1# SPDX-License-Identifier: GPL-2.0+ 2# 3# (C) Copyright 2000 - 2013 4# Wolfgang Denk, DENX Software Engineering, wd@denx.de. 5 6Summary: 7======== 8 9This directory contains the source code for U-Boot, a boot loader for 10Embedded boards based on PowerPC, ARM, MIPS and several other 11processors, which can be installed in a boot ROM and used to 12initialize and test the hardware or to download and run application 13code. 14 15The development of U-Boot is closely related to Linux: some parts of 16the source code originate in the Linux source tree, we have some 17header files in common, and special provision has been made to 18support booting of Linux images. 19 20Some attention has been paid to make this software easily 21configurable and extendable. For instance, all monitor commands are 22implemented with the same call interface, so that it's very easy to 23add new commands. Also, instead of permanently adding rarely used 24code (for instance hardware test utilities) to the monitor, you can 25load and run it dynamically. 26 27 28Status: 29======= 30 31In general, all boards for which a configuration option exists in the 32Makefile have been tested to some extent and can be considered 33"working". In fact, many of them are used in production systems. 34 35In case of problems see the CHANGELOG file to find out who contributed 36the specific port. In addition, there are various MAINTAINERS files 37scattered throughout the U-Boot source identifying the people or 38companies responsible for various boards and subsystems. 39 40Note: As of August, 2010, there is no longer a CHANGELOG file in the 41actual U-Boot source tree; however, it can be created dynamically 42from the Git log using: 43 44 make CHANGELOG 45 46 47Where to get help: 48================== 49 50In case you have questions about, problems with or contributions for 51U-Boot, you should send a message to the U-Boot mailing list at 52<u-boot@lists.denx.de>. There is also an archive of previous traffic 53on the mailing list - please search the archive before asking FAQ's. 54Please see https://lists.denx.de/pipermail/u-boot and 55https://marc.info/?l=u-boot 56 57Where to get source code: 58========================= 59 60The U-Boot source code is maintained in the Git repository at 61https://source.denx.de/u-boot/u-boot.git ; you can browse it online at 62https://source.denx.de/u-boot/u-boot 63 64The "Tags" links on this page allow you to download tarballs of 65any version you might be interested in. Official releases are also 66available from the DENX file server through HTTPS or FTP. 67https://ftp.denx.de/pub/u-boot/ 68ftp://ftp.denx.de/pub/u-boot/ 69 70 71Where we come from: 72=================== 73 74- start from 8xxrom sources 75- create PPCBoot project (https://sourceforge.net/projects/ppcboot) 76- clean up code 77- make it easier to add custom boards 78- make it possible to add other [PowerPC] CPUs 79- extend functions, especially: 80 * Provide extended interface to Linux boot loader 81 * S-Record download 82 * network boot 83 * ATA disk / SCSI ... boot 84- create ARMBoot project (https://sourceforge.net/projects/armboot) 85- add other CPU families (starting with ARM) 86- create U-Boot project (https://sourceforge.net/projects/u-boot) 87- current project page: see https://www.denx.de/wiki/U-Boot 88 89 90Names and Spelling: 91=================== 92 93The "official" name of this project is "Das U-Boot". The spelling 94"U-Boot" shall be used in all written text (documentation, comments 95in source files etc.). Example: 96 97 This is the README file for the U-Boot project. 98 99File names etc. shall be based on the string "u-boot". Examples: 100 101 include/asm-ppc/u-boot.h 102 103 #include <asm/u-boot.h> 104 105Variable names, preprocessor constants etc. shall be either based on 106the string "u_boot" or on "U_BOOT". Example: 107 108 U_BOOT_VERSION u_boot_logo 109 IH_OS_U_BOOT u_boot_hush_start 110 111 112Versioning: 113=========== 114 115Starting with the release in October 2008, the names of the releases 116were changed from numerical release numbers without deeper meaning 117into a time stamp based numbering. Regular releases are identified by 118names consisting of the calendar year and month of the release date. 119Additional fields (if present) indicate release candidates or bug fix 120releases in "stable" maintenance trees. 121 122Examples: 123 U-Boot v2009.11 - Release November 2009 124 U-Boot v2009.11.1 - Release 1 in version November 2009 stable tree 125 U-Boot v2010.09-rc1 - Release candidate 1 for September 2010 release 126 127 128Directory Hierarchy: 129==================== 130 131/arch Architecture-specific files 132 /arc Files generic to ARC architecture 133 /arm Files generic to ARM architecture 134 /m68k Files generic to m68k architecture 135 /microblaze Files generic to microblaze architecture 136 /mips Files generic to MIPS architecture 137 /nds32 Files generic to NDS32 architecture 138 /nios2 Files generic to Altera NIOS2 architecture 139 /powerpc Files generic to PowerPC architecture 140 /riscv Files generic to RISC-V architecture 141 /sandbox Files generic to HW-independent "sandbox" 142 /sh Files generic to SH architecture 143 /x86 Files generic to x86 architecture 144 /xtensa Files generic to Xtensa architecture 145/api Machine/arch-independent API for external apps 146/board Board-dependent files 147/cmd U-Boot commands functions 148/common Misc architecture-independent functions 149/configs Board default configuration files 150/disk Code for disk drive partition handling 151/doc Documentation (a mix of ReST and READMEs) 152/drivers Device drivers 153/dts Makefile for building internal U-Boot fdt. 154/env Environment support 155/examples Example code for standalone applications, etc. 156/fs Filesystem code (cramfs, ext2, jffs2, etc.) 157/include Header Files 158/lib Library routines generic to all architectures 159/Licenses Various license files 160/net Networking code 161/post Power On Self Test 162/scripts Various build scripts and Makefiles 163/test Various unit test files 164/tools Tools to build and sign FIT images, etc. 165 166Software Configuration: 167======================= 168 169Configuration is usually done using C preprocessor defines; the 170rationale behind that is to avoid dead code whenever possible. 171 172There are two classes of configuration variables: 173 174* Configuration _OPTIONS_: 175 These are selectable by the user and have names beginning with 176 "CONFIG_". 177 178* Configuration _SETTINGS_: 179 These depend on the hardware etc. and should not be meddled with if 180 you don't know what you're doing; they have names beginning with 181 "CONFIG_SYS_". 182 183Previously, all configuration was done by hand, which involved creating 184symbolic links and editing configuration files manually. More recently, 185U-Boot has added the Kbuild infrastructure used by the Linux kernel, 186allowing you to use the "make menuconfig" command to configure your 187build. 188 189 190Selection of Processor Architecture and Board Type: 191--------------------------------------------------- 192 193For all supported boards there are ready-to-use default 194configurations available; just type "make <board_name>_defconfig". 195 196Example: For a TQM823L module type: 197 198 cd u-boot 199 make TQM823L_defconfig 200 201Note: If you're looking for the default configuration file for a board 202you're sure used to be there but is now missing, check the file 203doc/README.scrapyard for a list of no longer supported boards. 204 205Sandbox Environment: 206-------------------- 207 208U-Boot can be built natively to run on a Linux host using the 'sandbox' 209board. This allows feature development which is not board- or architecture- 210specific to be undertaken on a native platform. The sandbox is also used to 211run some of U-Boot's tests. 212 213See doc/arch/sandbox.rst for more details. 214 215 216Board Initialisation Flow: 217-------------------------- 218 219This is the intended start-up flow for boards. This should apply for both 220SPL and U-Boot proper (i.e. they both follow the same rules). 221 222Note: "SPL" stands for "Secondary Program Loader," which is explained in 223more detail later in this file. 224 225At present, SPL mostly uses a separate code path, but the function names 226and roles of each function are the same. Some boards or architectures 227may not conform to this. At least most ARM boards which use 228CONFIG_SPL_FRAMEWORK conform to this. 229 230Execution typically starts with an architecture-specific (and possibly 231CPU-specific) start.S file, such as: 232 233 - arch/arm/cpu/armv7/start.S 234 - arch/powerpc/cpu/mpc83xx/start.S 235 - arch/mips/cpu/start.S 236 237and so on. From there, three functions are called; the purpose and 238limitations of each of these functions are described below. 239 240lowlevel_init(): 241 - purpose: essential init to permit execution to reach board_init_f() 242 - no global_data or BSS 243 - there is no stack (ARMv7 may have one but it will soon be removed) 244 - must not set up SDRAM or use console 245 - must only do the bare minimum to allow execution to continue to 246 board_init_f() 247 - this is almost never needed 248 - return normally from this function 249 250board_init_f(): 251 - purpose: set up the machine ready for running board_init_r(): 252 i.e. SDRAM and serial UART 253 - global_data is available 254 - stack is in SRAM 255 - BSS is not available, so you cannot use global/static variables, 256 only stack variables and global_data 257 258 Non-SPL-specific notes: 259 - dram_init() is called to set up DRAM. If already done in SPL this 260 can do nothing 261 262 SPL-specific notes: 263 - you can override the entire board_init_f() function with your own 264 version as needed. 265 - preloader_console_init() can be called here in extremis 266 - should set up SDRAM, and anything needed to make the UART work 267 - there is no need to clear BSS, it will be done by crt0.S 268 - for specific scenarios on certain architectures an early BSS *can* 269 be made available (via CONFIG_SPL_EARLY_BSS by moving the clearing 270 of BSS prior to entering board_init_f()) but doing so is discouraged. 271 Instead it is strongly recommended to architect any code changes 272 or additions such to not depend on the availability of BSS during 273 board_init_f() as indicated in other sections of this README to 274 maintain compatibility and consistency across the entire code base. 275 - must return normally from this function (don't call board_init_r() 276 directly) 277 278Here the BSS is cleared. For SPL, if CONFIG_SPL_STACK_R is defined, then at 279this point the stack and global_data are relocated to below 280CONFIG_SPL_STACK_R_ADDR. For non-SPL, U-Boot is relocated to run at the top of 281memory. 282 283board_init_r(): 284 - purpose: main execution, common code 285 - global_data is available 286 - SDRAM is available 287 - BSS is available, all static/global variables can be used 288 - execution eventually continues to main_loop() 289 290 Non-SPL-specific notes: 291 - U-Boot is relocated to the top of memory and is now running from 292 there. 293 294 SPL-specific notes: 295 - stack is optionally in SDRAM, if CONFIG_SPL_STACK_R is defined and 296 CONFIG_SPL_STACK_R_ADDR points into SDRAM 297 - preloader_console_init() can be called here - typically this is 298 done by selecting CONFIG_SPL_BOARD_INIT and then supplying a 299 spl_board_init() function containing this call 300 - loads U-Boot or (in falcon mode) Linux 301 302 303 304Configuration Options: 305---------------------- 306 307Configuration depends on the combination of board and CPU type; all 308such information is kept in a configuration file 309"include/configs/<board_name>.h". 310 311Example: For a TQM823L module, all configuration settings are in 312"include/configs/TQM823L.h". 313 314 315Many of the options are named exactly as the corresponding Linux 316kernel configuration options. The intention is to make it easier to 317build a config tool - later. 318 319- ARM Platform Bus Type(CCI): 320 CoreLink Cache Coherent Interconnect (CCI) is ARM BUS which 321 provides full cache coherency between two clusters of multi-core 322 CPUs and I/O coherency for devices and I/O masters 323 324 CONFIG_SYS_FSL_HAS_CCI400 325 326 Defined For SoC that has cache coherent interconnect 327 CCN-400 328 329 CONFIG_SYS_FSL_HAS_CCN504 330 331 Defined for SoC that has cache coherent interconnect CCN-504 332 333The following options need to be configured: 334 335- CPU Type: Define exactly one, e.g. CONFIG_MPC85XX. 336 337- Board Type: Define exactly one, e.g. CONFIG_MPC8540ADS. 338 339- 85xx CPU Options: 340 CONFIG_SYS_PPC64 341 342 Specifies that the core is a 64-bit PowerPC implementation (implements 343 the "64" category of the Power ISA). This is necessary for ePAPR 344 compliance, among other possible reasons. 345 346 CONFIG_SYS_FSL_TBCLK_DIV 347 348 Defines the core time base clock divider ratio compared to the 349 system clock. On most PQ3 devices this is 8, on newer QorIQ 350 devices it can be 16 or 32. The ratio varies from SoC to Soc. 351 352 CONFIG_SYS_FSL_PCIE_COMPAT 353 354 Defines the string to utilize when trying to match PCIe device 355 tree nodes for the given platform. 356 357 CONFIG_SYS_FSL_ERRATUM_A004510 358 359 Enables a workaround for erratum A004510. If set, 360 then CONFIG_SYS_FSL_ERRATUM_A004510_SVR_REV and 361 CONFIG_SYS_FSL_CORENET_SNOOPVEC_COREONLY must be set. 362 363 CONFIG_SYS_FSL_ERRATUM_A004510_SVR_REV 364 CONFIG_SYS_FSL_ERRATUM_A004510_SVR_REV2 (optional) 365 366 Defines one or two SoC revisions (low 8 bits of SVR) 367 for which the A004510 workaround should be applied. 368 369 The rest of SVR is either not relevant to the decision 370 of whether the erratum is present (e.g. p2040 versus 371 p2041) or is implied by the build target, which controls 372 whether CONFIG_SYS_FSL_ERRATUM_A004510 is set. 373 374 See Freescale App Note 4493 for more information about 375 this erratum. 376 377 CONFIG_A003399_NOR_WORKAROUND 378 Enables a workaround for IFC erratum A003399. It is only 379 required during NOR boot. 380 381 CONFIG_A008044_WORKAROUND 382 Enables a workaround for T1040/T1042 erratum A008044. It is only 383 required during NAND boot and valid for Rev 1.0 SoC revision 384 385 CONFIG_SYS_FSL_CORENET_SNOOPVEC_COREONLY 386 387 This is the value to write into CCSR offset 0x18600 388 according to the A004510 workaround. 389 390 CONFIG_SYS_FSL_DSP_DDR_ADDR 391 This value denotes start offset of DDR memory which is 392 connected exclusively to the DSP cores. 393 394 CONFIG_SYS_FSL_DSP_M2_RAM_ADDR 395 This value denotes start offset of M2 memory 396 which is directly connected to the DSP core. 397 398 CONFIG_SYS_FSL_DSP_M3_RAM_ADDR 399 This value denotes start offset of M3 memory which is directly 400 connected to the DSP core. 401 402 CONFIG_SYS_FSL_DSP_CCSRBAR_DEFAULT 403 This value denotes start offset of DSP CCSR space. 404 405 CONFIG_SYS_FSL_SINGLE_SOURCE_CLK 406 Single Source Clock is clocking mode present in some of FSL SoC's. 407 In this mode, a single differential clock is used to supply 408 clocks to the sysclock, ddrclock and usbclock. 409 410 CONFIG_SYS_CPC_REINIT_F 411 This CONFIG is defined when the CPC is configured as SRAM at the 412 time of U-Boot entry and is required to be re-initialized. 413 414 CONFIG_DEEP_SLEEP 415 Indicates this SoC supports deep sleep feature. If deep sleep is 416 supported, core will start to execute uboot when wakes up. 417 418- Generic CPU options: 419 CONFIG_SYS_BIG_ENDIAN, CONFIG_SYS_LITTLE_ENDIAN 420 421 Defines the endianess of the CPU. Implementation of those 422 values is arch specific. 423 424 CONFIG_SYS_FSL_DDR 425 Freescale DDR driver in use. This type of DDR controller is 426 found in mpc83xx, mpc85xx as well as some ARM core SoCs. 427 428 CONFIG_SYS_FSL_DDR_ADDR 429 Freescale DDR memory-mapped register base. 430 431 CONFIG_SYS_FSL_DDR_EMU 432 Specify emulator support for DDR. Some DDR features such as 433 deskew training are not available. 434 435 CONFIG_SYS_FSL_DDRC_GEN1 436 Freescale DDR1 controller. 437 438 CONFIG_SYS_FSL_DDRC_GEN2 439 Freescale DDR2 controller. 440 441 CONFIG_SYS_FSL_DDRC_GEN3 442 Freescale DDR3 controller. 443 444 CONFIG_SYS_FSL_DDRC_GEN4 445 Freescale DDR4 controller. 446 447 CONFIG_SYS_FSL_DDRC_ARM_GEN3 448 Freescale DDR3 controller for ARM-based SoCs. 449 450 CONFIG_SYS_FSL_DDR1 451 Board config to use DDR1. It can be enabled for SoCs with 452 Freescale DDR1 or DDR2 controllers, depending on the board 453 implemetation. 454 455 CONFIG_SYS_FSL_DDR2 456 Board config to use DDR2. It can be enabled for SoCs with 457 Freescale DDR2 or DDR3 controllers, depending on the board 458 implementation. 459 460 CONFIG_SYS_FSL_DDR3 461 Board config to use DDR3. It can be enabled for SoCs with 462 Freescale DDR3 or DDR3L controllers. 463 464 CONFIG_SYS_FSL_DDR3L 465 Board config to use DDR3L. It can be enabled for SoCs with 466 DDR3L controllers. 467 468 CONFIG_SYS_FSL_DDR4 469 Board config to use DDR4. It can be enabled for SoCs with 470 DDR4 controllers. 471 472 CONFIG_SYS_FSL_IFC_BE 473 Defines the IFC controller register space as Big Endian 474 475 CONFIG_SYS_FSL_IFC_LE 476 Defines the IFC controller register space as Little Endian 477 478 CONFIG_SYS_FSL_IFC_CLK_DIV 479 Defines divider of platform clock(clock input to IFC controller). 480 481 CONFIG_SYS_FSL_LBC_CLK_DIV 482 Defines divider of platform clock(clock input to eLBC controller). 483 484 CONFIG_SYS_FSL_PBL_PBI 485 It enables addition of RCW (Power on reset configuration) in built image. 486 Please refer doc/README.pblimage for more details 487 488 CONFIG_SYS_FSL_PBL_RCW 489 It adds PBI(pre-boot instructions) commands in u-boot build image. 490 PBI commands can be used to configure SoC before it starts the execution. 491 Please refer doc/README.pblimage for more details 492 493 CONFIG_SYS_FSL_DDR_BE 494 Defines the DDR controller register space as Big Endian 495 496 CONFIG_SYS_FSL_DDR_LE 497 Defines the DDR controller register space as Little Endian 498 499 CONFIG_SYS_FSL_DDR_SDRAM_BASE_PHY 500 Physical address from the view of DDR controllers. It is the 501 same as CONFIG_SYS_DDR_SDRAM_BASE for all Power SoCs. But 502 it could be different for ARM SoCs. 503 504 CONFIG_SYS_FSL_DDR_INTLV_256B 505 DDR controller interleaving on 256-byte. This is a special 506 interleaving mode, handled by Dickens for Freescale layerscape 507 SoCs with ARM core. 508 509 CONFIG_SYS_FSL_DDR_MAIN_NUM_CTRLS 510 Number of controllers used as main memory. 511 512 CONFIG_SYS_FSL_OTHER_DDR_NUM_CTRLS 513 Number of controllers used for other than main memory. 514 515 CONFIG_SYS_FSL_HAS_DP_DDR 516 Defines the SoC has DP-DDR used for DPAA. 517 518 CONFIG_SYS_FSL_SEC_BE 519 Defines the SEC controller register space as Big Endian 520 521 CONFIG_SYS_FSL_SEC_LE 522 Defines the SEC controller register space as Little Endian 523 524- MIPS CPU options: 525 CONFIG_SYS_INIT_SP_OFFSET 526 527 Offset relative to CONFIG_SYS_SDRAM_BASE for initial stack 528 pointer. This is needed for the temporary stack before 529 relocation. 530 531 CONFIG_XWAY_SWAP_BYTES 532 533 Enable compilation of tools/xway-swap-bytes needed for Lantiq 534 XWAY SoCs for booting from NOR flash. The U-Boot image needs to 535 be swapped if a flash programmer is used. 536 537- ARM options: 538 CONFIG_SYS_EXCEPTION_VECTORS_HIGH 539 540 Select high exception vectors of the ARM core, e.g., do not 541 clear the V bit of the c1 register of CP15. 542 543 COUNTER_FREQUENCY 544 Generic timer clock source frequency. 545 546 COUNTER_FREQUENCY_REAL 547 Generic timer clock source frequency if the real clock is 548 different from COUNTER_FREQUENCY, and can only be determined 549 at run time. 550 551- Tegra SoC options: 552 CONFIG_TEGRA_SUPPORT_NON_SECURE 553 554 Support executing U-Boot in non-secure (NS) mode. Certain 555 impossible actions will be skipped if the CPU is in NS mode, 556 such as ARM architectural timer initialization. 557 558- Linux Kernel Interface: 559 CONFIG_MEMSIZE_IN_BYTES [relevant for MIPS only] 560 561 When transferring memsize parameter to Linux, some versions 562 expect it to be in bytes, others in MB. 563 Define CONFIG_MEMSIZE_IN_BYTES to make it in bytes. 564 565 CONFIG_OF_LIBFDT 566 567 New kernel versions are expecting firmware settings to be 568 passed using flattened device trees (based on open firmware 569 concepts). 570 571 CONFIG_OF_LIBFDT 572 * New libfdt-based support 573 * Adds the "fdt" command 574 * The bootm command automatically updates the fdt 575 576 OF_TBCLK - The timebase frequency. 577 578 boards with QUICC Engines require OF_QE to set UCC MAC 579 addresses 580 581 CONFIG_OF_BOARD_SETUP 582 583 Board code has addition modification that it wants to make 584 to the flat device tree before handing it off to the kernel 585 586 CONFIG_OF_SYSTEM_SETUP 587 588 Other code has addition modification that it wants to make 589 to the flat device tree before handing it off to the kernel. 590 This causes ft_system_setup() to be called before booting 591 the kernel. 592 593 CONFIG_OF_IDE_FIXUP 594 595 U-Boot can detect if an IDE device is present or not. 596 If not, and this new config option is activated, U-Boot 597 removes the ATA node from the DTS before booting Linux, 598 so the Linux IDE driver does not probe the device and 599 crash. This is needed for buggy hardware (uc101) where 600 no pull down resistor is connected to the signal IDE5V_DD7. 601 602 CONFIG_MACH_TYPE [relevant for ARM only][mandatory] 603 604 This setting is mandatory for all boards that have only one 605 machine type and must be used to specify the machine type 606 number as it appears in the ARM machine registry 607 (see https://www.arm.linux.org.uk/developer/machines/). 608 Only boards that have multiple machine types supported 609 in a single configuration file and the machine type is 610 runtime discoverable, do not have to use this setting. 611 612- vxWorks boot parameters: 613 614 bootvx constructs a valid bootline using the following 615 environments variables: bootdev, bootfile, ipaddr, netmask, 616 serverip, gatewayip, hostname, othbootargs. 617 It loads the vxWorks image pointed bootfile. 618 619 Note: If a "bootargs" environment is defined, it will override 620 the defaults discussed just above. 621 622- Cache Configuration: 623 CONFIG_SYS_L2CACHE_OFF- Do not enable L2 cache in U-Boot 624 625- Cache Configuration for ARM: 626 CONFIG_SYS_L2_PL310 - Enable support for ARM PL310 L2 cache 627 controller 628 CONFIG_SYS_PL310_BASE - Physical base address of PL310 629 controller register space 630 631- Serial Ports: 632 CONFIG_PL011_SERIAL 633 634 Define this if you want support for Amba PrimeCell PL011 UARTs. 635 636 CONFIG_PL011_CLOCK 637 638 If you have Amba PrimeCell PL011 UARTs, set this variable to 639 the clock speed of the UARTs. 640 641 CONFIG_PL01x_PORTS 642 643 If you have Amba PrimeCell PL010 or PL011 UARTs on your board, 644 define this to a list of base addresses for each (supported) 645 port. See e.g. include/configs/versatile.h 646 647 CONFIG_SERIAL_HW_FLOW_CONTROL 648 649 Define this variable to enable hw flow control in serial driver. 650 Current user of this option is drivers/serial/nsl16550.c driver 651 652- Autoboot Command: 653 CONFIG_BOOTCOMMAND 654 Only needed when CONFIG_BOOTDELAY is enabled; 655 define a command string that is automatically executed 656 when no character is read on the console interface 657 within "Boot Delay" after reset. 658 659 CONFIG_RAMBOOT and CONFIG_NFSBOOT 660 The value of these goes into the environment as 661 "ramboot" and "nfsboot" respectively, and can be used 662 as a convenience, when switching between booting from 663 RAM and NFS. 664 665- Serial Download Echo Mode: 666 CONFIG_LOADS_ECHO 667 If defined to 1, all characters received during a 668 serial download (using the "loads" command) are 669 echoed back. This might be needed by some terminal 670 emulations (like "cu"), but may as well just take 671 time on others. This setting #define's the initial 672 value of the "loads_echo" environment variable. 673 674- Kgdb Serial Baudrate: (if CONFIG_CMD_KGDB is defined) 675 CONFIG_KGDB_BAUDRATE 676 Select one of the baudrates listed in 677 CONFIG_SYS_BAUDRATE_TABLE, see below. 678 679- Removal of commands 680 If no commands are needed to boot, you can disable 681 CONFIG_CMDLINE to remove them. In this case, the command line 682 will not be available, and when U-Boot wants to execute the 683 boot command (on start-up) it will call board_run_command() 684 instead. This can reduce image size significantly for very 685 simple boot procedures. 686 687- Regular expression support: 688 CONFIG_REGEX 689 If this variable is defined, U-Boot is linked against 690 the SLRE (Super Light Regular Expression) library, 691 which adds regex support to some commands, as for 692 example "env grep" and "setexpr". 693 694- Device tree: 695 CONFIG_OF_CONTROL 696 If this variable is defined, U-Boot will use a device tree 697 to configure its devices, instead of relying on statically 698 compiled #defines in the board file. This option is 699 experimental and only available on a few boards. The device 700 tree is available in the global data as gd->fdt_blob. 701 702 U-Boot needs to get its device tree from somewhere. This can 703 be done using one of the three options below: 704 705 CONFIG_OF_EMBED 706 If this variable is defined, U-Boot will embed a device tree 707 binary in its image. This device tree file should be in the 708 board directory and called <soc>-<board>.dts. The binary file 709 is then picked up in board_init_f() and made available through 710 the global data structure as gd->fdt_blob. 711 712 CONFIG_OF_SEPARATE 713 If this variable is defined, U-Boot will build a device tree 714 binary. It will be called u-boot.dtb. Architecture-specific 715 code will locate it at run-time. Generally this works by: 716 717 cat u-boot.bin u-boot.dtb >image.bin 718 719 and in fact, U-Boot does this for you, creating a file called 720 u-boot-dtb.bin which is useful in the common case. You can 721 still use the individual files if you need something more 722 exotic. 723 724 CONFIG_OF_BOARD 725 If this variable is defined, U-Boot will use the device tree 726 provided by the board at runtime instead of embedding one with 727 the image. Only boards defining board_fdt_blob_setup() support 728 this option (see include/fdtdec.h file). 729 730- Watchdog: 731 CONFIG_WATCHDOG 732 If this variable is defined, it enables watchdog 733 support for the SoC. There must be support in the SoC 734 specific code for a watchdog. For the 8xx 735 CPUs, the SIU Watchdog feature is enabled in the SYPCR 736 register. When supported for a specific SoC is 737 available, then no further board specific code should 738 be needed to use it. 739 740 CONFIG_HW_WATCHDOG 741 When using a watchdog circuitry external to the used 742 SoC, then define this variable and provide board 743 specific code for the "hw_watchdog_reset" function. 744 745 CONFIG_SYS_WATCHDOG_FREQ 746 Some platforms automatically call WATCHDOG_RESET() 747 from the timer interrupt handler every 748 CONFIG_SYS_WATCHDOG_FREQ interrupts. If not set by the 749 board configuration file, a default of CONFIG_SYS_HZ/2 750 (i.e. 500) is used. Setting CONFIG_SYS_WATCHDOG_FREQ 751 to 0 disables calling WATCHDOG_RESET() from the timer 752 interrupt. 753 754- Real-Time Clock: 755 756 When CONFIG_CMD_DATE is selected, the type of the RTC 757 has to be selected, too. Define exactly one of the 758 following options: 759 760 CONFIG_RTC_PCF8563 - use Philips PCF8563 RTC 761 CONFIG_RTC_MC13XXX - use MC13783 or MC13892 RTC 762 CONFIG_RTC_MC146818 - use MC146818 RTC 763 CONFIG_RTC_DS1307 - use Maxim, Inc. DS1307 RTC 764 CONFIG_RTC_DS1337 - use Maxim, Inc. DS1337 RTC 765 CONFIG_RTC_DS1338 - use Maxim, Inc. DS1338 RTC 766 CONFIG_RTC_DS1339 - use Maxim, Inc. DS1339 RTC 767 CONFIG_RTC_DS164x - use Dallas DS164x RTC 768 CONFIG_RTC_ISL1208 - use Intersil ISL1208 RTC 769 CONFIG_RTC_MAX6900 - use Maxim, Inc. MAX6900 RTC 770 CONFIG_RTC_DS1337_NOOSC - Turn off the OSC output for DS1337 771 CONFIG_SYS_RV3029_TCR - enable trickle charger on 772 RV3029 RTC. 773 774 Note that if the RTC uses I2C, then the I2C interface 775 must also be configured. See I2C Support, below. 776 777- GPIO Support: 778 CONFIG_PCA953X - use NXP's PCA953X series I2C GPIO 779 780 The CONFIG_SYS_I2C_PCA953X_WIDTH option specifies a list of 781 chip-ngpio pairs that tell the PCA953X driver the number of 782 pins supported by a particular chip. 783 784 Note that if the GPIO device uses I2C, then the I2C interface 785 must also be configured. See I2C Support, below. 786 787- I/O tracing: 788 When CONFIG_IO_TRACE is selected, U-Boot intercepts all I/O 789 accesses and can checksum them or write a list of them out 790 to memory. See the 'iotrace' command for details. This is 791 useful for testing device drivers since it can confirm that 792 the driver behaves the same way before and after a code 793 change. Currently this is supported on sandbox and arm. To 794 add support for your architecture, add '#include <iotrace.h>' 795 to the bottom of arch/<arch>/include/asm/io.h and test. 796 797 Example output from the 'iotrace stats' command is below. 798 Note that if the trace buffer is exhausted, the checksum will 799 still continue to operate. 800 801 iotrace is enabled 802 Start: 10000000 (buffer start address) 803 Size: 00010000 (buffer size) 804 Offset: 00000120 (current buffer offset) 805 Output: 10000120 (start + offset) 806 Count: 00000018 (number of trace records) 807 CRC32: 9526fb66 (CRC32 of all trace records) 808 809- Timestamp Support: 810 811 When CONFIG_TIMESTAMP is selected, the timestamp 812 (date and time) of an image is printed by image 813 commands like bootm or iminfo. This option is 814 automatically enabled when you select CONFIG_CMD_DATE . 815 816- Partition Labels (disklabels) Supported: 817 Zero or more of the following: 818 CONFIG_MAC_PARTITION Apple's MacOS partition table. 819 CONFIG_ISO_PARTITION ISO partition table, used on CDROM etc. 820 CONFIG_EFI_PARTITION GPT partition table, common when EFI is the 821 bootloader. Note 2TB partition limit; see 822 disk/part_efi.c 823 CONFIG_SCSI) you must configure support for at 824 least one non-MTD partition type as well. 825 826- IDE Reset method: 827 CONFIG_IDE_RESET_ROUTINE - this is defined in several 828 board configurations files but used nowhere! 829 830 CONFIG_IDE_RESET - is this is defined, IDE Reset will 831 be performed by calling the function 832 ide_set_reset(int reset) 833 which has to be defined in a board specific file 834 835- ATAPI Support: 836 CONFIG_ATAPI 837 838 Set this to enable ATAPI support. 839 840- LBA48 Support 841 CONFIG_LBA48 842 843 Set this to enable support for disks larger than 137GB 844 Also look at CONFIG_SYS_64BIT_LBA. 845 Whithout these , LBA48 support uses 32bit variables and will 'only' 846 support disks up to 2.1TB. 847 848 CONFIG_SYS_64BIT_LBA: 849 When enabled, makes the IDE subsystem use 64bit sector addresses. 850 Default is 32bit. 851 852- SCSI Support: 853 CONFIG_SYS_SCSI_MAX_LUN [8], CONFIG_SYS_SCSI_MAX_SCSI_ID [7] and 854 CONFIG_SYS_SCSI_MAX_DEVICE [CONFIG_SYS_SCSI_MAX_SCSI_ID * 855 CONFIG_SYS_SCSI_MAX_LUN] can be adjusted to define the 856 maximum numbers of LUNs, SCSI ID's and target 857 devices. 858 859 The environment variable 'scsidevs' is set to the number of 860 SCSI devices found during the last scan. 861 862- NETWORK Support (PCI): 863 CONFIG_E1000 864 Support for Intel 8254x/8257x gigabit chips. 865 866 CONFIG_E1000_SPI 867 Utility code for direct access to the SPI bus on Intel 8257x. 868 This does not do anything useful unless you set at least one 869 of CONFIG_CMD_E1000 or CONFIG_E1000_SPI_GENERIC. 870 871 CONFIG_E1000_SPI_GENERIC 872 Allow generic access to the SPI bus on the Intel 8257x, for 873 example with the "sspi" command. 874 875 CONFIG_NATSEMI 876 Support for National dp83815 chips. 877 878 CONFIG_NS8382X 879 Support for National dp8382[01] gigabit chips. 880 881- NETWORK Support (other): 882 883 CONFIG_DRIVER_AT91EMAC 884 Support for AT91RM9200 EMAC. 885 886 CONFIG_RMII 887 Define this to use reduced MII inteface 888 889 CONFIG_DRIVER_AT91EMAC_QUIET 890 If this defined, the driver is quiet. 891 The driver doen't show link status messages. 892 893 CONFIG_CALXEDA_XGMAC 894 Support for the Calxeda XGMAC device 895 896 CONFIG_LAN91C96 897 Support for SMSC's LAN91C96 chips. 898 899 CONFIG_LAN91C96_USE_32_BIT 900 Define this to enable 32 bit addressing 901 902 CONFIG_SMC91111 903 Support for SMSC's LAN91C111 chip 904 905 CONFIG_SMC91111_BASE 906 Define this to hold the physical address 907 of the device (I/O space) 908 909 CONFIG_SMC_USE_32_BIT 910 Define this if data bus is 32 bits 911 912 CONFIG_SMC_USE_IOFUNCS 913 Define this to use i/o functions instead of macros 914 (some hardware wont work with macros) 915 916 CONFIG_SYS_DAVINCI_EMAC_PHY_COUNT 917 Define this if you have more then 3 PHYs. 918 919 CONFIG_FTGMAC100 920 Support for Faraday's FTGMAC100 Gigabit SoC Ethernet 921 922 CONFIG_FTGMAC100_EGIGA 923 Define this to use GE link update with gigabit PHY. 924 Define this if FTGMAC100 is connected to gigabit PHY. 925 If your system has 10/100 PHY only, it might not occur 926 wrong behavior. Because PHY usually return timeout or 927 useless data when polling gigabit status and gigabit 928 control registers. This behavior won't affect the 929 correctnessof 10/100 link speed update. 930 931 CONFIG_SH_ETHER 932 Support for Renesas on-chip Ethernet controller 933 934 CONFIG_SH_ETHER_USE_PORT 935 Define the number of ports to be used 936 937 CONFIG_SH_ETHER_PHY_ADDR 938 Define the ETH PHY's address 939 940 CONFIG_SH_ETHER_CACHE_WRITEBACK 941 If this option is set, the driver enables cache flush. 942 943- TPM Support: 944 CONFIG_TPM 945 Support TPM devices. 946 947 CONFIG_TPM_TIS_INFINEON 948 Support for Infineon i2c bus TPM devices. Only one device 949 per system is supported at this time. 950 951 CONFIG_TPM_TIS_I2C_BURST_LIMITATION 952 Define the burst count bytes upper limit 953 954 CONFIG_TPM_ST33ZP24 955 Support for STMicroelectronics TPM devices. Requires DM_TPM support. 956 957 CONFIG_TPM_ST33ZP24_I2C 958 Support for STMicroelectronics ST33ZP24 I2C devices. 959 Requires TPM_ST33ZP24 and I2C. 960 961 CONFIG_TPM_ST33ZP24_SPI 962 Support for STMicroelectronics ST33ZP24 SPI devices. 963 Requires TPM_ST33ZP24 and SPI. 964 965 CONFIG_TPM_ATMEL_TWI 966 Support for Atmel TWI TPM device. Requires I2C support. 967 968 CONFIG_TPM_TIS_LPC 969 Support for generic parallel port TPM devices. Only one device 970 per system is supported at this time. 971 972 CONFIG_TPM_TIS_BASE_ADDRESS 973 Base address where the generic TPM device is mapped 974 to. Contemporary x86 systems usually map it at 975 0xfed40000. 976 977 CONFIG_TPM 978 Define this to enable the TPM support library which provides 979 functional interfaces to some TPM commands. 980 Requires support for a TPM device. 981 982 CONFIG_TPM_AUTH_SESSIONS 983 Define this to enable authorized functions in the TPM library. 984 Requires CONFIG_TPM and CONFIG_SHA1. 985 986- USB Support: 987 At the moment only the UHCI host controller is 988 supported (PIP405, MIP405); define 989 CONFIG_USB_UHCI to enable it. 990 define CONFIG_USB_KEYBOARD to enable the USB Keyboard 991 and define CONFIG_USB_STORAGE to enable the USB 992 storage devices. 993 Note: 994 Supported are USB Keyboards and USB Floppy drives 995 (TEAC FD-05PUB). 996 997 CONFIG_USB_EHCI_TXFIFO_THRESH enables setting of the 998 txfilltuning field in the EHCI controller on reset. 999 1000 CONFIG_USB_DWC2_REG_ADDR the physical CPU address of the DWC2
1001 HW module registers. 1002 1003- USB Device: 1004 Define the below if you wish to use the USB console. 1005 Once firmware is rebuilt from a serial console issue the 1006 command "setenv stdin usbtty; setenv stdout usbtty" and 1007 attach your USB cable. The Unix command "dmesg" should print 1008 it has found a new device. The environment variable usbtty 1009 can be set to gserial or cdc_acm to enable your device to 1010 appear to a USB host as a Linux gserial device or a 1011 Common Device Class Abstract Control Model serial device. 1012 If you select usbtty = gserial you should be able to enumerate 1013 a Linux host by 1014 # modprobe usbserial vendor=0xVendorID product=0xProductID 1015 else if using cdc_acm, simply setting the environment 1016 variable usbtty to be cdc_acm should suffice. The following 1017 might be defined in YourBoardName.h 1018 1019 CONFIG_USB_DEVICE 1020 Define this to build a UDC device 1021 1022 CONFIG_USB_TTY 1023 Define this to have a tty type of device available to 1024 talk to the UDC device 1025 1026 CONFIG_USBD_HS 1027 Define this to enable the high speed support for usb 1028 device and usbtty. If this feature is enabled, a routine 1029 int is_usbd_high_speed(void) 1030 also needs to be defined by the driver to dynamically poll 1031 whether the enumeration has succeded at high speed or full 1032 speed. 1033 1034 CONFIG_SYS_CONSOLE_IS_IN_ENV 1035 Define this if you want stdin, stdout &/or stderr to 1036 be set to usbtty. 1037 1038 If you have a USB-IF assigned VendorID then you may wish to 1039 define your own vendor specific values either in BoardName.h 1040 or directly in usbd_vendor_info.h. If you don't define 1041 CONFIG_USBD_MANUFACTURER, CONFIG_USBD_PRODUCT_NAME, 1042 CONFIG_USBD_VENDORID and CONFIG_USBD_PRODUCTID, then U-Boot 1043 should pretend to be a Linux device to it's target host. 1044 1045 CONFIG_USBD_MANUFACTURER 1046 Define this string as the name of your company for 1047 - CONFIG_USBD_MANUFACTURER "my company" 1048 1049 CONFIG_USBD_PRODUCT_NAME 1050 Define this string as the name of your product 1051 - CONFIG_USBD_PRODUCT_NAME "acme usb device" 1052 1053 CONFIG_USBD_VENDORID 1054 Define this as your assigned Vendor ID from the USB 1055 Implementors Forum. This *must* be a genuine Vendor ID 1056 to avoid polluting the USB namespace. 1057 - CONFIG_USBD_VENDORID 0xFFFF 1058 1059 CONFIG_USBD_PRODUCTID 1060 Define this as the unique Product ID 1061 for your device 1062 - CONFIG_USBD_PRODUCTID 0xFFFF 1063 1064- ULPI Layer Support: 1065 The ULPI (UTMI Low Pin (count) Interface) PHYs are supported via 1066 the generic ULPI layer. The generic layer accesses the ULPI PHY 1067 via the platform viewport, so you need both the genric layer and 1068 the viewport enabled. Currently only Chipidea/ARC based 1069 viewport is supported. 1070 To enable the ULPI layer support, define CONFIG_USB_ULPI and 1071 CONFIG_USB_ULPI_VIEWPORT in your board configuration file. 1072 If your ULPI phy needs a different reference clock than the 1073 standard 24 MHz then you have to define CONFIG_ULPI_REF_CLK to 1074 the appropriate value in Hz. 1075 1076- MMC Support: 1077 The MMC controller on the Intel PXA is supported. To 1078 enable this define CONFIG_MMC. The MMC can be 1079 accessed from the boot prompt by mapping the device 1080 to physical memory similar to flash. Command line is 1081 enabled with CONFIG_CMD_MMC. The MMC driver also works with 1082 the FAT fs. This is enabled with CONFIG_CMD_FAT. 1083 1084 CONFIG_SH_MMCIF 1085 Support for Renesas on-chip MMCIF controller 1086 1087 CONFIG_SH_MMCIF_ADDR 1088 Define the base address of MMCIF registers 1089 1090 CONFIG_SH_MMCIF_CLK 1091 Define the clock frequency for MMCIF 1092 1093- USB Device Firmware Update (DFU) class support: 1094 CONFIG_DFU_OVER_USB 1095 This enables the USB portion of the DFU USB class 1096 1097 CONFIG_DFU_NAND 1098 This enables support for exposing NAND devices via DFU. 1099 1100 CONFIG_DFU_RAM 1101 This enables support for exposing RAM via DFU. 1102 Note: DFU spec refer to non-volatile memory usage, but 1103 allow usages beyond the scope of spec - here RAM usage, 1104 one that would help mostly the developer. 1105 1106 CONFIG_SYS_DFU_DATA_BUF_SIZE 1107 Dfu transfer uses a buffer before writing data to the 1108 raw storage device. Make the size (in bytes) of this buffer 1109 configurable. The size of this buffer is also configurable 1110 through the "dfu_bufsiz" environment variable. 1111 1112 CONFIG_SYS_DFU_MAX_FILE_SIZE 1113 When updating files rather than the raw storage device, 1114 we use a static buffer to copy the file into and then write 1115 the buffer once we've been given the whole file. Define 1116 this to the maximum filesize (in bytes) for the buffer. 1117 Default is 4 MiB if undefined. 1118 1119 DFU_DEFAULT_POLL_TIMEOUT 1120 Poll timeout [ms], is the timeout a device can send to the 1121 host. The host must wait for this timeout before sending 1122 a subsequent DFU_GET_STATUS request to the device. 1123 1124 DFU_MANIFEST_POLL_TIMEOUT 1125 Poll timeout [ms], which the device sends to the host when 1126 entering dfuMANIFEST state. Host waits this timeout, before 1127 sending again an USB request to the device. 1128 1129- Journaling Flash filesystem support: 1130 CONFIG_JFFS2_NAND 1131 Define these for a default partition on a NAND device 1132 1133 CONFIG_SYS_JFFS2_FIRST_SECTOR, 1134 CONFIG_SYS_JFFS2_FIRST_BANK, CONFIG_SYS_JFFS2_NUM_BANKS 1135 Define these for a default partition on a NOR device 1136 1137- Keyboard Support: 1138 See Kconfig help for available keyboard drivers. 1139 1140 CONFIG_KEYBOARD 1141 1142 Define this to enable a custom keyboard support. 1143 This simply calls drv_keyboard_init() which must be 1144 defined in your board-specific files. This option is deprecated 1145 and is only used by novena. For new boards, use driver model 1146 instead. 1147 1148- Video support: 1149 CONFIG_FSL_DIU_FB 1150 Enable the Freescale DIU video driver. Reference boards for 1151 SOCs that have a DIU should define this macro to enable DIU 1152 support, and should also define these other macros: 1153 1154 CONFIG_SYS_DIU_ADDR 1155 CONFIG_VIDEO 1156 CONFIG_CFB_CONSOLE 1157 CONFIG_VIDEO_SW_CURSOR 1158 CONFIG_VGA_AS_SINGLE_DEVICE 1159 CONFIG_VIDEO_LOGO 1160 CONFIG_VIDEO_BMP_LOGO 1161 1162 The DIU driver will look for the 'video-mode' environment 1163 variable, and if defined, enable the DIU as a console during 1164 boot. See the documentation file doc/README.video for a 1165 description of this variable. 1166 1167- LCD Support: CONFIG_LCD 1168 1169 Define this to enable LCD support (for output to LCD 1170 display); also select one of the supported displays 1171 by defining one of these: 1172 1173 CONFIG_ATMEL_LCD: 1174 1175 HITACHI TX09D70VM1CCA, 3.5", 240x320. 1176 1177 CONFIG_NEC_NL6448AC33: 1178 1179 NEC NL6448AC33-18. Active, color, single scan. 1180 1181 CONFIG_NEC_NL6448BC20 1182 1183 NEC NL6448BC20-08. 6.5", 640x480. 1184 Active, color, single scan. 1185 1186 CONFIG_NEC_NL6448BC33_54 1187 1188 NEC NL6448BC33-54. 10.4", 640x480. 1189 Active, color, single scan. 1190 1191 CONFIG_SHARP_16x9 1192 1193 Sharp 320x240. Active, color, single scan. 1194 It isn't 16x9, and I am not sure what it is. 1195 1196 CONFIG_SHARP_LQ64D341 1197 1198 Sharp LQ64D341 display, 640x480. 1199 Active, color, single scan. 1200 1201 CONFIG_HLD1045 1202 1203 HLD1045 display, 640x480. 1204 Active, color, single scan. 1205 1206 CONFIG_OPTREX_BW 1207 1208 Optrex CBL50840-2 NF-FW 99 22 M5 1209 or 1210 Hitachi LMG6912RPFC-00T 1211 or 1212 Hitachi SP14Q002 1213 1214 320x240. Black & white. 1215 1216 CONFIG_LCD_ALIGNMENT 1217 1218 Normally the LCD is page-aligned (typically 4KB). If this is 1219 defined then the LCD will be aligned to this value instead. 1220 For ARM it is sometimes useful to use MMU_SECTION_SIZE 1221 here, since it is cheaper to change data cache settings on 1222 a per-section basis. 1223 1224 1225 CONFIG_LCD_ROTATION 1226 1227 Sometimes, for example if the display is mounted in portrait 1228 mode or even if it's mounted landscape but rotated by 180degree, 1229 we need to rotate our content of the display relative to the 1230 framebuffer, so that user can read the messages which are 1231 printed out. 1232 Once CONFIG_LCD_ROTATION is defined, the lcd_console will be 1233 initialized with a given rotation from "vl_rot" out of 1234 "vidinfo_t" which is provided by the board specific code. 1235 The value for vl_rot is coded as following (matching to 1236 fbcon=rotate:<n> linux-kernel commandline): 1237 0 = no rotation respectively 0 degree 1238 1 = 90 degree rotation 1239 2 = 180 degree rotation 1240 3 = 270 degree rotation 1241 1242 If CONFIG_LCD_ROTATION is not defined, the console will be 1243 initialized with 0degree rotation. 1244 1245 CONFIG_LCD_BMP_RLE8 1246 1247 Support drawing of RLE8-compressed bitmaps on the LCD. 1248 1249 CONFIG_I2C_EDID 1250 1251 Enables an 'i2c edid' command which can read EDID 1252 information over I2C from an attached LCD display. 1253 1254- MII/PHY support: 1255 CONFIG_PHY_CLOCK_FREQ (ppc4xx) 1256 1257 The clock frequency of the MII bus 1258 1259 CONFIG_PHY_RESET_DELAY 1260 1261 Some PHY like Intel LXT971A need extra delay after 1262 reset before any MII register access is possible. 1263 For such PHY, set this option to the usec delay 1264 required. (minimum 300usec for LXT971A) 1265 1266 CONFIG_PHY_CMD_DELAY (ppc4xx) 1267 1268 Some PHY like Intel LXT971A need extra delay after 1269 command issued before MII status register can be read 1270 1271- IP address: 1272 CONFIG_IPADDR 1273 1274 Define a default value for the IP address to use for 1275 the default Ethernet interface, in case this is not 1276 determined through e.g. bootp. 1277 (Environment variable "ipaddr") 1278 1279- Server IP address: 1280 CONFIG_SERVERIP 1281 1282 Defines a default value for the IP address of a TFTP 1283 server to contact when using the "tftboot" command. 1284 (Environment variable "serverip") 1285 1286 CONFIG_KEEP_SERVERADDR 1287 1288 Keeps the server's MAC address, in the env 'serveraddr' 1289 for passing to bootargs (like Linux's netconsole option) 1290 1291- Gateway IP address: 1292 CONFIG_GATEWAYIP 1293 1294 Defines a default value for the IP address of the 1295 default router where packets to other networks are 1296 sent to. 1297 (Environment variable "gatewayip") 1298 1299- Subnet mask: 1300 CONFIG_NETMASK 1301 1302 Defines a default value for the subnet mask (or 1303 routing prefix) which is used to determine if an IP 1304 address belongs to the local subnet or needs to be 1305 forwarded through a router. 1306 (Environment variable "netmask") 1307 1308- BOOTP Recovery Mode: 1309 CONFIG_BOOTP_RANDOM_DELAY 1310 1311 If you have many targets in a network that try to 1312 boot using BOOTP, you may want to avoid that all 1313 systems send out BOOTP requests at precisely the same 1314 moment (which would happen for instance at recovery 1315 from a power failure, when all systems will try to 1316 boot, thus flooding the BOOTP server. Defining 1317 CONFIG_BOOTP_RANDOM_DELAY causes a random delay to be 1318 inserted before sending out BOOTP requests. The 1319 following delays are inserted then: 1320 1321 1st BOOTP request: delay 0 ... 1 sec 1322 2nd BOOTP request: delay 0 ... 2 sec 1323 3rd BOOTP request: delay 0 ... 4 sec 1324 4th and following 1325 BOOTP requests: delay 0 ... 8 sec 1326 1327 CONFIG_BOOTP_ID_CACHE_SIZE 1328 1329 BOOTP packets are uniquely identified using a 32-bit ID. The 1330 server will copy the ID from client requests to responses and 1331 U-Boot will use this to determine if it is the destination of 1332 an incoming response. Some servers will check that addresses 1333 aren't in use before handing them out (usually using an ARP 1334 ping) and therefore take up to a few hundred milliseconds to 1335 respond. Network congestion may also influence the time it 1336 takes for a response to make it back to the client. If that 1337 time is too long, U-Boot will retransmit requests. In order 1338 to allow earlier responses to still be accepted after these 1339 retransmissions, U-Boot's BOOTP client keeps a small cache of 1340 IDs. The CONFIG_BOOTP_ID_CACHE_SIZE controls the size of this 1341 cache. The default is to keep IDs for up to four outstanding 1342 requests. Increasing this will allow U-Boot to accept offers 1343 from a BOOTP client in networks with unusually high latency. 1344 1345- DHCP Advanced Options: 1346 You can fine tune the DHCP functionality by defining 1347 CONFIG_BOOTP_* symbols: 1348 1349 CONFIG_BOOTP_NISDOMAIN 1350 CONFIG_BOOTP_BOOTFILESIZE 1351 CONFIG_BOOTP_NTPSERVER 1352 CONFIG_BOOTP_TIMEOFFSET 1353 CONFIG_BOOTP_VENDOREX 1354 CONFIG_BOOTP_MAY_FAIL 1355 1356 CONFIG_BOOTP_SERVERIP - TFTP server will be the serverip 1357 environment variable, not the BOOTP server. 1358 1359 CONFIG_BOOTP_MAY_FAIL - If the DHCP server is not found 1360 after the configured retry count, the call will fail 1361 instead of starting over. This can be used to fail over 1362 to Link-local IP address configuration if the DHCP server 1363 is not available. 1364 1365 CONFIG_BOOTP_DHCP_REQUEST_DELAY 1366 1367 A 32bit value in microseconds for a delay between 1368 receiving a "DHCP Offer" and sending the "DHCP Request". 1369 This fixes a problem with certain DHCP servers that don't 1370 respond 100% of the time to a "DHCP request". E.g. On an 1371 AT91RM9200 processor running at 180MHz, this delay needed 1372 to be *at least* 15,000 usec before a Windows Server 2003 1373 DHCP server would reply 100% of the time. I recommend at 1374 least 50,000 usec to be safe. The alternative is to hope 1375 that one of the retries will be successful but note that 1376 the DHCP timeout and retry process takes a longer than 1377 this delay. 1378 1379 - Link-local IP address negotiation: 1380 Negotiate with other link-local clients on the local network 1381 for an address that doesn't require explicit configuration. 1382 This is especially useful if a DHCP server cannot be guaranteed 1383 to exist in all environments that the device must operate. 1384 1385 See doc/README.link-local for more information. 1386 1387 - MAC address from environment variables 1388 1389 FDT_SEQ_MACADDR_FROM_ENV 1390 1391 Fix-up device tree with MAC addresses fetched sequentially from 1392 environment variables. This config work on assumption that 1393 non-usable ethernet node of device-tree are either not present 1394 or their status has been marked as "disabled". 1395 1396 - CDP Options: 1397 CONFIG_CDP_DEVICE_ID 1398 1399 The device id used in CDP trigger frames. 1400 1401 CONFIG_CDP_DEVICE_ID_PREFIX 1402 1403 A two character string which is prefixed to the MAC address 1404 of the device. 1405 1406 CONFIG_CDP_PORT_ID 1407 1408 A printf format string which contains the ascii name of 1409 the port. Normally is set to "eth%d" which sets 1410 eth0 for the first Ethernet, eth1 for the second etc. 1411 1412 CONFIG_CDP_CAPABILITIES 1413 1414 A 32bit integer which indicates the device capabilities; 1415 0x00000010 for a normal host which does not forwards. 1416 1417 CONFIG_CDP_VERSION 1418 1419 An ascii string containing the version of the software. 1420 1421 CONFIG_CDP_PLATFORM 1422 1423 An ascii string containing the name of the platform. 1424 1425 CONFIG_CDP_TRIGGER 1426 1427 A 32bit integer sent on the trigger. 1428 1429 CONFIG_CDP_POWER_CONSUMPTION 1430 1431 A 16bit integer containing the power consumption of the 1432 device in .1 of milliwatts. 1433 1434 CONFIG_CDP_APPLIANCE_VLAN_TYPE 1435 1436 A byte containing the id of the VLAN. 1437 1438- Status LED: CONFIG_LED_STATUS 1439 1440 Several configurations allow to display the current 1441 status using a LED. For instance, the LED will blink 1442 fast while running U-Boot code, stop blinking as 1443 soon as a reply to a BOOTP request was received, and 1444 start blinking slow once the Linux kernel is running 1445 (supported by a status LED driver in the Linux 1446 kernel). Defining CONFIG_LED_STATUS enables this 1447 feature in U-Boot. 1448 1449 Additional options: 1450 1451 CONFIG_LED_STATUS_GPIO 1452 The status LED can be connected to a GPIO pin. 1453 In such cases, the gpio_led driver can be used as a 1454 status LED backend implementation. Define CONFIG_LED_STATUS_GPIO 1455 to include the gpio_led driver in the U-Boot binary. 1456 1457 CONFIG_GPIO_LED_INVERTED_TABLE 1458 Some GPIO connected LEDs may have inverted polarity in which 1459 case the GPIO high value corresponds to LED off state and 1460 GPIO low value corresponds to LED on state. 1461 In such cases CONFIG_GPIO_LED_INVERTED_TABLE may be defined 1462 with a list of GPIO LEDs that have inverted polarity. 1463 1464- I2C Support: CONFIG_SYS_I2C_LEGACY 1465 1466 Note: This is deprecated in favour of driver model. Use 1467 CONFIG_DM_I2C instead. 1468 1469 This enable the legacy i2c subsystem, and will allow you to use 1470 i2c commands at the u-boot command line (as long as you set 1471 CONFIG_SYS_I2C_SOFT_SPEED and CONFIG_SYS_I2C_SOFT_SLAVE 1472 for defining speed and slave address 1473 - activate second bus with I2C_SOFT_DECLARATIONS2 define 1474 CONFIG_SYS_I2C_SOFT_SPEED_2 and CONFIG_SYS_I2C_SOFT_SLAVE_2 1475 for defining speed and slave address 1476 - activate third bus with I2C_SOFT_DECLARATIONS3 define 1477 CONFIG_SYS_I2C_SOFT_SPEED_3 and CONFIG_SYS_I2C_SOFT_SLAVE_3 1478 for defining speed and slave address 1479 - activate fourth bus with I2C_SOFT_DECLARATIONS4 define 1480 CONFIG_SYS_I2C_SOFT_SPEED_4 and CONFIG_SYS_I2C_SOFT_SLAVE_4 1481 for defining speed and slave address 1482 1483 - drivers/i2c/fsl_i2c.c: 1484 - activate i2c driver with CONFIG_SYS_I2C_FSL 1485 define CONFIG_SYS_FSL_I2C_OFFSET for setting the register 1486 offset CONFIG_SYS_FSL_I2C_SPEED for the i2c speed and 1487 CONFIG_SYS_FSL_I2C_SLAVE for the slave addr of the first 1488 bus. 1489 - If your board supports a second fsl i2c bus, define 1490 CONFIG_SYS_FSL_I2C2_OFFSET for the register offset 1491 CONFIG_SYS_FSL_I2C2_SPEED for the speed and 1492 CONFIG_SYS_FSL_I2C2_SLAVE for the slave address of the 1493 second bus. 1494 1495 - drivers/i2c/tegra_i2c.c: 1496 - activate this driver with CONFIG_SYS_I2C_TEGRA 1497 - This driver adds 4 i2c buses with a fix speed from 1498 100000 and the slave addr 0! 1499 1500 - drivers/i2c/ppc4xx_i2c.c 1501 - activate this driver with CONFIG_SYS_I2C_PPC4XX 1502 - CONFIG_SYS_I2C_PPC4XX_CH0 activate hardware channel 0 1503 - CONFIG_SYS_I2C_PPC4XX_CH1 activate hardware channel 1 1504 1505 - drivers/i2c/i2c_mxc.c 1506 - activate this driver with CONFIG_SYS_I2C_MXC 1507 - enable bus 1 with CONFIG_SYS_I2C_MXC_I2C1 1508 - enable bus 2 with CONFIG_SYS_I2C_MXC_I2C2 1509 - enable bus 3 with CONFIG_SYS_I2C_MXC_I2C3 1510 - enable bus 4 with CONFIG_SYS_I2C_MXC_I2C4 1511 - define speed for bus 1 with CONFIG_SYS_MXC_I2C1_SPEED 1512 - define slave for bus 1 with CONFIG_SYS_MXC_I2C1_SLAVE 1513 - define speed for bus 2 with CONFIG_SYS_MXC_I2C2_SPEED 1514 - define slave for bus 2 with CONFIG_SYS_MXC_I2C2_SLAVE 1515 - define speed for bus 3 with CONFIG_SYS_MXC_I2C3_SPEED 1516 - define slave for bus 3 with CONFIG_SYS_MXC_I2C3_SLAVE 1517 - define speed for bus 4 with CONFIG_SYS_MXC_I2C4_SPEED 1518 - define slave for bus 4 with CONFIG_SYS_MXC_I2C4_SLAVE 1519 If those defines are not set, default value is 100000 1520 for speed, and 0 for slave. 1521 1522 - drivers/i2c/rcar_i2c.c: 1523 - activate this driver with CONFIG_SYS_I2C_RCAR 1524 - This driver adds 4 i2c buses 1525 1526 - drivers/i2c/sh_i2c.c: 1527 - activate this driver with CONFIG_SYS_I2C_SH 1528 - This driver adds from 2 to 5 i2c buses 1529 1530 - CONFIG_SYS_I2C_SH_BASE0 for setting the register channel 0 1531 - CONFIG_SYS_I2C_SH_SPEED0 for for the speed channel 0 1532 - CONFIG_SYS_I2C_SH_BASE1 for setting the register channel 1 1533 - CONFIG_SYS_I2C_SH_SPEED1 for for the speed channel 1 1534 - CONFIG_SYS_I2C_SH_BASE2 for setting the register channel 2 1535 - CONFIG_SYS_I2C_SH_SPEED2 for for the speed channel 2 1536 - CONFIG_SYS_I2C_SH_BASE3 for setting the register channel 3 1537 - CONFIG_SYS_I2C_SH_SPEED3 for for the speed channel 3 1538 - CONFIG_SYS_I2C_SH_BASE4 for setting the register channel 4 1539 - CONFIG_SYS_I2C_SH_SPEED4 for for the speed channel 4 1540 - CONFIG_SYS_I2C_SH_NUM_CONTROLLERS for number of i2c buses 1541 1542 - drivers/i2c/omap24xx_i2c.c 1543 - activate this driver with CONFIG_SYS_I2C_OMAP24XX 1544 - CONFIG_SYS_OMAP24_I2C_SPEED speed channel 0 1545 - CONFIG_SYS_OMAP24_I2C_SLAVE slave addr channel 0 1546 - CONFIG_SYS_OMAP24_I2C_SPEED1 speed channel 1 1547 - CONFIG_SYS_OMAP24_I2C_SLAVE1 slave addr channel 1 1548 - CONFIG_SYS_OMAP24_I2C_SPEED2 speed channel 2 1549 - CONFIG_SYS_OMAP24_I2C_SLAVE2 slave addr channel 2 1550 - CONFIG_SYS_OMAP24_I2C_SPEED3 speed channel 3 1551 - CONFIG_SYS_OMAP24_I2C_SLAVE3 slave addr channel 3 1552 - CONFIG_SYS_OMAP24_I2C_SPEED4 speed channel 4 1553 - CONFIG_SYS_OMAP24_I2C_SLAVE4 slave addr channel 4 1554 1555 - drivers/i2c/s3c24x0_i2c.c: 1556 - activate this driver with CONFIG_SYS_I2C_S3C24X0 1557 - This driver adds i2c buses (11 for Exynos5250, Exynos5420 1558 9 i2c buses for Exynos4 and 1 for S3C24X0 SoCs from Samsung) 1559 with a fix speed from 100000 and the slave addr 0! 1560 1561 - drivers/i2c/ihs_i2c.c 1562 - activate this driver with CONFIG_SYS_I2C_IHS 1563 - CONFIG_SYS_I2C_IHS_CH0 activate hardware channel 0 1564 - CONFIG_SYS_I2C_IHS_SPEED_0 speed channel 0 1565 - CONFIG_SYS_I2C_IHS_SLAVE_0 slave addr channel 0 1566 - CONFIG_SYS_I2C_IHS_CH1 activate hardware channel 1 1567 - CONFIG_SYS_I2C_IHS_SPEED_1 speed channel 1 1568 - CONFIG_SYS_I2C_IHS_SLAVE_1 slave addr channel 1 1569 - CONFIG_SYS_I2C_IHS_CH2 activate hardware channel 2 1570 - CONFIG_SYS_I2C_IHS_SPEED_2 speed channel 2 1571 - CONFIG_SYS_I2C_IHS_SLAVE_2 slave addr channel 2 1572 - CONFIG_SYS_I2C_IHS_CH3 activate hardware channel 3 1573 - CONFIG_SYS_I2C_IHS_SPEED_3 speed channel 3 1574 - CONFIG_SYS_I2C_IHS_SLAVE_3 slave addr channel 3 1575 - activate dual channel with CONFIG_SYS_I2C_IHS_DUAL 1576 - CONFIG_SYS_I2C_IHS_SPEED_0_1 speed channel 0_1 1577 - CONFIG_SYS_I2C_IHS_SLAVE_0_1 slave addr channel 0_1 1578 - CONFIG_SYS_I2C_IHS_SPEED_1_1 speed channel 1_1 1579 - CONFIG_SYS_I2C_IHS_SLAVE_1_1 slave addr channel 1_1 1580 - CONFIG_SYS_I2C_IHS_SPEED_2_1 speed channel 2_1 1581 - CONFIG_SYS_I2C_IHS_SLAVE_2_1 slave addr channel 2_1 1582 - CONFIG_SYS_I2C_IHS_SPEED_3_1 speed channel 3_1 1583 - CONFIG_SYS_I2C_IHS_SLAVE_3_1 slave addr channel 3_1 1584 1585 additional defines: 1586 1587 CONFIG_SYS_NUM_I2C_BUSES 1588 Hold the number of i2c buses you want to use. 1589 1590 CONFIG_SYS_I2C_DIRECT_BUS 1591 define this, if you don't use i2c muxes on your hardware. 1592 if CONFIG_SYS_I2C_MAX_HOPS is not defined or == 0 you can 1593 omit this define. 1594 1595 CONFIG_SYS_I2C_MAX_HOPS 1596 define how many muxes are maximal consecutively connected 1597 on one i2c bus. If you not use i2c muxes, omit this 1598 define. 1599 1600 CONFIG_SYS_I2C_BUSES 1601 hold a list of buses you want to use, only used if 1602 CONFIG_SYS_I2C_DIRECT_BUS is not defined, for example 1603 a board with CONFIG_SYS_I2C_MAX_HOPS = 1 and 1604 CONFIG_SYS_NUM_I2C_BUSES = 9: 1605 1606 CONFIG_SYS_I2C_BUSES {{0, {I2C_NULL_HOP}}, \ 1607 {0, {{I2C_MUX_PCA9547, 0x70, 1}}}, \ 1608 {0, {{I2C_MUX_PCA9547, 0x70, 2}}}, \ 1609 {0, {{I2C_MUX_PCA9547, 0x70, 3}}}, \ 1610 {0, {{I2C_MUX_PCA9547, 0x70, 4}}}, \ 1611 {0, {{I2C_MUX_PCA9547, 0x70, 5}}}, \ 1612 {1, {I2C_NULL_HOP}}, \ 1613 {1, {{I2C_MUX_PCA9544, 0x72, 1}}}, \ 1614 {1, {{I2C_MUX_PCA9544, 0x72, 2}}}, \ 1615 } 1616 1617 which defines 1618 bus 0 on adapter 0 without a mux 1619 bus 1 on adapter 0 with a PCA9547 on address 0x70 port 1 1620 bus 2 on adapter 0 with a PCA9547 on address 0x70 port 2 1621 bus 3 on adapter 0 with a PCA9547 on address 0x70 port 3 1622 bus 4 on adapter 0 with a PCA9547 on address 0x70 port 4 1623 bus 5 on adapter 0 with a PCA9547 on address 0x70 port 5 1624 bus 6 on adapter 1 without a mux 1625 bus 7 on adapter 1 with a PCA9544 on address 0x72 port 1 1626 bus 8 on adapter 1 with a PCA9544 on address 0x72 port 2 1627 1628 If you do not have i2c muxes on your board, omit this define. 1629 1630- Legacy I2C Support: 1631 If you use the software i2c interface (CONFIG_SYS_I2C_SOFT) 1632 then the following macros need to be defined (examples are 1633 from include/configs/lwmon.h): 1634 1635 I2C_INIT 1636 1637 (Optional). Any commands necessary to enable the I2C 1638 controller or configure ports. 1639 1640 eg: #define I2C_INIT (immr->im_cpm.cp_pbdir |= PB_SCL) 1641 1642 I2C_ACTIVE 1643 1644 The code necessary to make the I2C data line active 1645 (driven). If the data line is open collector, this 1646 define can be null. 1647 1648 eg: #define I2C_ACTIVE (immr->im_cpm.cp_pbdir |= PB_SDA) 1649 1650 I2C_TRISTATE 1651 1652 The code necessary to make the I2C data line tri-stated 1653 (inactive). If the data line is open collector, this 1654 define can be null. 1655 1656 eg: #define I2C_TRISTATE (immr->im_cpm.cp_pbdir &= ~PB_SDA) 1657 1658 I2C_READ 1659 1660 Code that returns true if the I2C data line is high, 1661 false if it is low. 1662 1663 eg: #define I2C_READ ((immr->im_cpm.cp_pbdat & PB_SDA) != 0) 1664 1665 I2C_SDA(bit) 1666 1667 If <bit> is true, sets the I2C data line high. If it 1668 is false, it clears it (low). 1669 1670 eg: #define I2C_SDA(bit) \ 1671 if(bit) immr->im_cpm.cp_pbdat |= PB_SDA; \ 1672 else immr->im_cpm.cp_pbdat &= ~PB_SDA 1673 1674 I2C_SCL(bit) 1675 1676 If <bit> is true, sets the I2C clock line high. If it 1677 is false, it clears it (low). 1678 1679 eg: #define I2C_SCL(bit) \ 1680 if(bit) immr->im_cpm.cp_pbdat |= PB_SCL; \ 1681 else immr->im_cpm.cp_pbdat &= ~PB_SCL 1682 1683 I2C_DELAY 1684 1685 This delay is invoked four times per clock cycle so this 1686 controls the rate of data transfer. The data rate thus 1687 is 1 / (I2C_DELAY * 4). Often defined to be something 1688 like: 1689 1690 #define I2C_DELAY udelay(2) 1691 1692 CONFIG_SOFT_I2C_GPIO_SCL / CONFIG_SOFT_I2C_GPIO_SDA 1693 1694 If your arch supports the generic GPIO framework (asm/gpio.h), 1695 then you may alternatively define the two GPIOs that are to be 1696 used as SCL / SDA. Any of the previous I2C_xxx macros will 1697 have GPIO-based defaults assigned to them as appropriate. 1698 1699 You should define these to the GPIO value as given directly to 1700 the generic GPIO functions. 1701 1702 CONFIG_SYS_I2C_INIT_BOARD 1703 1704 When a board is reset during an i2c bus transfer 1705 chips might think that the current transfer is still 1706 in progress. On some boards it is possible to access 1707 the i2c SCLK line directly, either by using the 1708 processor pin as a GPIO or by having a second pin 1709 connected to the bus. If this option is defined a 1710 custom i2c_init_board() routine in boards/xxx/board.c 1711 is run early in the boot sequence. 1712 1713 CONFIG_I2C_MULTI_BUS 1714 1715 This option allows the use of multiple I2C buses, each of which 1716 must have a controller. At any point in time, only one bus is 1717 active. To switch to a different bus, use the 'i2c dev' command. 1718 Note that bus numbering is zero-based. 1719 1720 CONFIG_SYS_I2C_NOPROBES 1721 1722 This option specifies a list of I2C devices that will be skipped 1723 when the 'i2c probe' command is issued. If CONFIG_I2C_MULTI_BUS 1724 is set, specify a list of bus-device pairs. Otherwise, specify 1725 a 1D array of device addresses 1726 1727 e.g. 1728 #undef CONFIG_I2C_MULTI_BUS 1729 #define CONFIG_SYS_I2C_NOPROBES {0x50,0x68} 1730 1731 will skip addresses 0x50 and 0x68 on a board with one I2C bus 1732 1733 #define CONFIG_I2C_MULTI_BUS 1734 #define CONFIG_SYS_I2C_NOPROBES {{0,0x50},{0,0x68},{1,0x54}} 1735 1736 will skip addresses 0x50 and 0x68 on bus 0 and address 0x54 on bus 1 1737 1738 CONFIG_SYS_SPD_BUS_NUM 1739 1740 If defined, then this indicates the I2C bus number for DDR SPD. 1741 If not defined, then U-Boot assumes that SPD is on I2C bus 0. 1742 1743 CONFIG_SYS_RTC_BUS_NUM 1744 1745 If defined, then this indicates the I2C bus number for the RTC. 1746 If not defined, then U-Boot assumes that RTC is on I2C bus 0. 1747 1748 CONFIG_SOFT_I2C_READ_REPEATED_START 1749 1750 defining this will force the i2c_read() function in 1751 the soft_i2c driver to perform an I2C repeated start 1752 between writing the address pointer and reading the 1753 data. If this define is omitted the default behaviour 1754 of doing a stop-start sequence will be used. Most I2C 1755 devices can use either method, but some require one or 1756 the other. 1757 1758- SPI Support: CONFIG_SPI 1759 1760 Enables SPI driver (so far only tested with 1761 SPI EEPROM, also an instance works with Crystal A/D and 1762 D/As on the SACSng board) 1763 1764 CONFIG_SOFT_SPI 1765 1766 Enables a software (bit-bang) SPI driver rather than 1767 using hardware support. This is a general purpose 1768 driver that only requires three general I/O port pins 1769 (two outputs, one input) to function. If this is 1770 defined, the board configuration must define several 1771 SPI configuration items (port pins to use, etc). For 1772 an example, see include/configs/sacsng.h. 1773 1774 CONFIG_SYS_SPI_MXC_WAIT 1775 Timeout for waiting until spi transfer completed. 1776 default: (CONFIG_SYS_HZ/100) /* 10 ms */ 1777 1778- FPGA Support: CONFIG_FPGA 1779 1780 Enables FPGA subsystem. 1781 1782 CONFIG_FPGA_<vendor> 1783 1784 Enables support for specific chip vendors. 1785 (ALTERA, XILINX) 1786 1787 CONFIG_FPGA_<family> 1788 1789 Enables support for FPGA family. 1790 (SPARTAN2, SPARTAN3, VIRTEX2, CYCLONE2, ACEX1K, ACEX) 1791 1792 CONFIG_FPGA_COUNT 1793 1794 Specify the number of FPGA devices to support. 1795 1796 CONFIG_SYS_FPGA_PROG_FEEDBACK 1797 1798 Enable printing of hash marks during FPGA configuration. 1799 1800 CONFIG_SYS_FPGA_CHECK_BUSY 1801 1802 Enable checks on FPGA configuration interface busy 1803 status by the configuration function. This option 1804 will require a board or device specific function to 1805 be written. 1806 1807 CONFIG_FPGA_DELAY 1808 1809 If defined, a function that provides delays in the FPGA 1810 configuration driver. 1811 1812 CONFIG_SYS_FPGA_CHECK_CTRLC 1813 Allow Control-C to interrupt FPGA configuration 1814 1815 CONFIG_SYS_FPGA_CHECK_ERROR 1816 1817 Check for configuration errors during FPGA bitfile 1818 loading. For example, abort during Virtex II 1819 configuration if the INIT_B line goes low (which 1820 indicated a CRC error). 1821 1822 CONFIG_SYS_FPGA_WAIT_INIT 1823 1824 Maximum time to wait for the INIT_B line to de-assert 1825 after PROB_B has been de-asserted during a Virtex II 1826 FPGA configuration sequence. The default time is 500 1827 ms. 1828 1829 CONFIG_SYS_FPGA_WAIT_BUSY 1830 1831 Maximum time to wait for BUSY to de-assert during 1832 Virtex II FPGA configuration. The default is 5 ms. 1833 1834 CONFIG_SYS_FPGA_WAIT_CONFIG 1835 1836 Time to wait after FPGA configuration. The default is 1837 200 ms. 1838 1839- Configuration Management: 1840 1841 CONFIG_IDENT_STRING 1842 1843 If defined, this string will be added to the U-Boot 1844 version information (U_BOOT_VERSION) 1845 1846- Vendor Parameter Protection: 1847 1848 U-Boot considers the values of the environment 1849 variables "serial#" (Board Serial Number) and 1850 "ethaddr" (Ethernet Address) to be parameters that 1851 are set once by the board vendor / manufacturer, and 1852 protects these variables from casual modification by 1853 the user. Once set, these variables are read-only, 1854 and write or delete attempts are rejected. You can 1855 change this behaviour: 1856 1857 If CONFIG_ENV_OVERWRITE is #defined in your config 1858 file, the write protection for vendor parameters is 1859 completely disabled. Anybody can change or delete 1860 these parameters. 1861 1862 Alternatively, if you define _both_ an ethaddr in the 1863 default env _and_ CONFIG_OVERWRITE_ETHADDR_ONCE, a default 1864 Ethernet address is installed in the environment, 1865 which can be changed exactly ONCE by the user. [The 1866 serial# is unaffected by this, i. e. it remains 1867 read-only.] 1868 1869 The same can be accomplished in a more flexible way 1870 for any variable by configuring the type of access 1871 to allow for those variables in the ".flags" variable 1872 or define CONFIG_ENV_FLAGS_LIST_STATIC. 1873 1874- Protected RAM: 1875 CONFIG_PRAM 1876 1877 Define this variable to enable the reservation of 1878 "protected RAM", i. e. RAM which is not overwritten 1879 by U-Boot. Define CONFIG_PRAM to hold the number of 1880 kB you want to reserve for pRAM. You can overwrite 1881 this default value by defining an environment 1882 variable "pram" to the number of kB you want to 1883 reserve. Note that the board info structure will 1884 still show the full amount of RAM. If pRAM is 1885 reserved, a new environment variable "mem" will 1886 automatically be defined to hold the amount of 1887 remaining RAM in a form that can be passed as boot 1888 argument to Linux, for instance like that: 1889 1890 setenv bootargs ... mem=\${mem} 1891 saveenv 1892 1893 This way you can tell Linux not to use this memory, 1894 either, which results in a memory region that will 1895 not be affected by reboots. 1896 1897 *WARNING* If your board configuration uses automatic 1898 detection of the RAM size, you must make sure that 1899 this memory test is non-destructive. So far, the 1900 following board configurations are known to be 1901 "pRAM-clean": 1902 1903 IVMS8, IVML24, SPD8xx, 1904 HERMES, IP860, RPXlite, LWMON, 1905 FLAGADM 1906 1907- Access to physical memory region (> 4GB) 1908 Some basic support is provided for operations on memory not 1909 normally accessible to U-Boot - e.g. some architectures 1910 support access to more than 4GB of memory on 32-bit 1911 machines using physical address extension or similar. 1912 Define CONFIG_PHYSMEM to access this basic support, which 1913 currently only supports clearing the memory. 1914 1915- Error Recovery: 1916 CONFIG_NET_RETRY_COUNT 1917 1918 This variable defines the number of retries for 1919 network operations like ARP, RARP, TFTP, or BOOTP 1920 before giving up the operation. If not defined, a 1921 default value of 5 is used. 1922 1923 CONFIG_ARP_TIMEOUT 1924 1925 Timeout waiting for an ARP reply in milliseconds. 1926 1927 CONFIG_NFS_TIMEOUT 1928 1929 Timeout in milliseconds used in NFS protocol. 1930 If you encounter "ERROR: Cannot umount" in nfs command, 1931 try longer timeout such as 1932 #define CONFIG_NFS_TIMEOUT 10000UL 1933 1934 Note: 1935 1936 In the current implementation, the local variables 1937 space and global environment variables space are 1938 separated. Local variables are those you define by 1939 simply typing `name=value'. To access a local 1940 variable later on, you have write `$name' or 1941 `${name}'; to execute the contents of a variable 1942 directly type `$name' at the command prompt. 1943 1944 Global environment variables are those you use 1945 setenv/printenv to work with. To run a command stored 1946 in such a variable, you need to use the run command, 1947 and you must not use the '$' sign to access them. 1948 1949 To store commands and special characters in a 1950 variable, please use double quotation marks 1951 surrounding the whole text of the variable, instead 1952 of the backslashes before semicolons and special 1953 symbols. 1954 1955- Command Line Editing and History: 1956 CONFIG_CMDLINE_PS_SUPPORT 1957 1958 Enable support for changing the command prompt string 1959 at run-time. Only static string is supported so far. 1960 The string is obtained from environment variables PS1 1961 and PS2. 1962 1963- Default Environment: 1964 CONFIG_EXTRA_ENV_SETTINGS 1965 1966 Define this to contain any number of null terminated 1967 strings (variable = value pairs) that will be part of 1968 the default environment compiled into the boot image. 1969 1970 For example, place something like this in your 1971 board's config file: 1972 1973 #define CONFIG_EXTRA_ENV_SETTINGS \ 1974 "myvar1=value1\0" \ 1975 "myvar2=value2\0" 1976 1977 Warning: This method is based on knowledge about the 1978 internal format how the environment is stored by the 1979 U-Boot code. This is NOT an official, exported 1980 interface! Although it is unlikely that this format 1981 will change soon, there is no guarantee either. 1982 You better know what you are doing here. 1983 1984 Note: overly (ab)use of the default environment is 1985 discouraged. Make sure to check other ways to preset 1986 the environment like the "source" command or the 1987 boot command first. 1988 1989 CONFIG_DELAY_ENVIRONMENT 1990 1991 Normally the environment is loaded when the board is 1992 initialised so that it is available to U-Boot. This inhibits 1993 that so that the environment is not available until 1994 explicitly loaded later by U-Boot code. With CONFIG_OF_CONTROL 1995 this is instead controlled by the value of 1996 /config/load-environment. 1997 1998- TFTP Fixed UDP Port: 1999 CONFIG_TFTP_PORT 2000
2001 If this is defined, the environment variable tftpsrcp 2002 is used to supply the TFTP UDP source port value. 2003 If tftpsrcp isn't defined, the normal pseudo-random port 2004 number generator is used. 2005 2006 Also, the environment variable tftpdstp is used to supply 2007 the TFTP UDP destination port value. If tftpdstp isn't 2008 defined, the normal port 69 is used. 2009 2010 The purpose for tftpsrcp is to allow a TFTP server to 2011 blindly start the TFTP transfer using the pre-configured 2012 target IP address and UDP port. This has the effect of 2013 "punching through" the (Windows XP) firewall, allowing 2014 the remainder of the TFTP transfer to proceed normally. 2015 A better solution is to properly configure the firewall, 2016 but sometimes that is not allowed. 2017 2018 CONFIG_STANDALONE_LOAD_ADDR 2019 2020 This option defines a board specific value for the 2021 address where standalone program gets loaded, thus 2022 overwriting the architecture dependent default 2023 settings. 2024 2025- Frame Buffer Address: 2026 CONFIG_FB_ADDR 2027 2028 Define CONFIG_FB_ADDR if you want to use specific 2029 address for frame buffer. This is typically the case 2030 when using a graphics controller has separate video 2031 memory. U-Boot will then place the frame buffer at 2032 the given address instead of dynamically reserving it 2033 in system RAM by calling lcd_setmem(), which grabs 2034 the memory for the frame buffer depending on the 2035 configured panel size. 2036 2037 Please see board_init_f function. 2038 2039- Automatic software updates via TFTP server 2040 CONFIG_UPDATE_TFTP 2041 CONFIG_UPDATE_TFTP_CNT_MAX 2042 CONFIG_UPDATE_TFTP_MSEC_MAX 2043 2044 These options enable and control the auto-update feature; 2045 for a more detailed description refer to doc/README.update. 2046 2047- MTD Support (mtdparts command, UBI support) 2048 CONFIG_MTD_UBI_WL_THRESHOLD 2049 This parameter defines the maximum difference between the highest 2050 erase counter value and the lowest erase counter value of eraseblocks 2051 of UBI devices. When this threshold is exceeded, UBI starts performing 2052 wear leveling by means of moving data from eraseblock with low erase 2053 counter to eraseblocks with high erase counter. 2054 2055 The default value should be OK for SLC NAND flashes, NOR flashes and 2056 other flashes which have eraseblock life-cycle 100000 or more. 2057 However, in case of MLC NAND flashes which typically have eraseblock 2058 life-cycle less than 10000, the threshold should be lessened (e.g., 2059 to 128 or 256, although it does not have to be power of 2). 2060 2061 default: 4096 2062 2063 CONFIG_MTD_UBI_BEB_LIMIT 2064 This option specifies the maximum bad physical eraseblocks UBI 2065 expects on the MTD device (per 1024 eraseblocks). If the 2066 underlying flash does not admit of bad eraseblocks (e.g. NOR 2067 flash), this value is ignored. 2068 2069 NAND datasheets often specify the minimum and maximum NVM 2070 (Number of Valid Blocks) for the flashes' endurance lifetime. 2071 The maximum expected bad eraseblocks per 1024 eraseblocks 2072 then can be calculated as "1024 * (1 - MinNVB / MaxNVB)", 2073 which gives 20 for most NANDs (MaxNVB is basically the total 2074 count of eraseblocks on the chip). 2075 2076 To put it differently, if this value is 20, UBI will try to 2077 reserve about 1.9% of physical eraseblocks for bad blocks 2078 handling. And that will be 1.9% of eraseblocks on the entire 2079 NAND chip, not just the MTD partition UBI attaches. This means 2080 that if you have, say, a NAND flash chip admits maximum 40 bad 2081 eraseblocks, and it is split on two MTD partitions of the same 2082 size, UBI will reserve 40 eraseblocks when attaching a 2083 partition. 2084 2085 default: 20 2086 2087 CONFIG_MTD_UBI_FASTMAP 2088 Fastmap is a mechanism which allows attaching an UBI device 2089 in nearly constant time. Instead of scanning the whole MTD device it 2090 only has to locate a checkpoint (called fastmap) on the device. 2091 The on-flash fastmap contains all information needed to attach 2092 the device. Using fastmap makes only sense on large devices where 2093 attaching by scanning takes long. UBI will not automatically install 2094 a fastmap on old images, but you can set the UBI parameter 2095 CONFIG_MTD_UBI_FASTMAP_AUTOCONVERT to 1 if you want so. Please note 2096 that fastmap-enabled images are still usable with UBI implementations 2097 without fastmap support. On typical flash devices the whole fastmap 2098 fits into one PEB. UBI will reserve PEBs to hold two fastmaps. 2099 2100 CONFIG_MTD_UBI_FASTMAP_AUTOCONVERT 2101 Set this parameter to enable fastmap automatically on images 2102 without a fastmap. 2103 default: 0 2104 2105 CONFIG_MTD_UBI_FM_DEBUG 2106 Enable UBI fastmap debug 2107 default: 0 2108 2109- SPL framework 2110 CONFIG_SPL 2111 Enable building of SPL globally. 2112 2113 CONFIG_SPL_LDSCRIPT 2114 LDSCRIPT for linking the SPL binary. 2115 2116 CONFIG_SPL_MAX_FOOTPRINT 2117 Maximum size in memory allocated to the SPL, BSS included. 2118 When defined, the linker checks that the actual memory 2119 used by SPL from _start to __bss_end does not exceed it. 2120 CONFIG_SPL_MAX_FOOTPRINT and CONFIG_SPL_BSS_MAX_SIZE 2121 must not be both defined at the same time. 2122 2123 CONFIG_SPL_MAX_SIZE 2124 Maximum size of the SPL image (text, data, rodata, and 2125 linker lists sections), BSS excluded. 2126 When defined, the linker checks that the actual size does 2127 not exceed it. 2128 2129 CONFIG_SPL_RELOC_TEXT_BASE 2130 Address to relocate to. If unspecified, this is equal to 2131 CONFIG_SPL_TEXT_BASE (i.e. no relocation is done). 2132 2133 CONFIG_SPL_BSS_START_ADDR 2134 Link address for the BSS within the SPL binary. 2135 2136 CONFIG_SPL_BSS_MAX_SIZE 2137 Maximum size in memory allocated to the SPL BSS. 2138 When defined, the linker checks that the actual memory used 2139 by SPL from __bss_start to __bss_end does not exceed it. 2140 CONFIG_SPL_MAX_FOOTPRINT and CONFIG_SPL_BSS_MAX_SIZE 2141 must not be both defined at the same time. 2142 2143 CONFIG_SPL_STACK 2144 Adress of the start of the stack SPL will use 2145 2146 CONFIG_SPL_PANIC_ON_RAW_IMAGE 2147 When defined, SPL will panic() if the image it has 2148 loaded does not have a signature. 2149 Defining this is useful when code which loads images 2150 in SPL cannot guarantee that absolutely all read errors 2151 will be caught. 2152 An example is the LPC32XX MLC NAND driver, which will 2153 consider that a completely unreadable NAND block is bad, 2154 and thus should be skipped silently. 2155 2156 CONFIG_SPL_RELOC_STACK 2157 Adress of the start of the stack SPL will use after 2158 relocation. If unspecified, this is equal to 2159 CONFIG_SPL_STACK. 2160 2161 CONFIG_SYS_SPL_MALLOC_START 2162 Starting address of the malloc pool used in SPL. 2163 When this option is set the full malloc is used in SPL and 2164 it is set up by spl_init() and before that, the simple malloc() 2165 can be used if CONFIG_SYS_MALLOC_F is defined. 2166 2167 CONFIG_SYS_SPL_MALLOC_SIZE 2168 The size of the malloc pool used in SPL. 2169 2170 CONFIG_SPL_OS_BOOT 2171 Enable booting directly to an OS from SPL. 2172 See also: doc/README.falcon 2173 2174 CONFIG_SPL_DISPLAY_PRINT 2175 For ARM, enable an optional function to print more information 2176 about the running system. 2177 2178 CONFIG_SPL_INIT_MINIMAL 2179 Arch init code should be built for a very small image 2180 2181 CONFIG_SYS_MMCSD_RAW_MODE_U_BOOT_PARTITION 2182 Partition on the MMC to load U-Boot from when the MMC is being 2183 used in raw mode 2184 2185 CONFIG_SYS_MMCSD_RAW_MODE_KERNEL_SECTOR 2186 Sector to load kernel uImage from when MMC is being 2187 used in raw mode (for Falcon mode) 2188 2189 CONFIG_SYS_MMCSD_RAW_MODE_ARGS_SECTOR, 2190 CONFIG_SYS_MMCSD_RAW_MODE_ARGS_SECTORS 2191 Sector and number of sectors to load kernel argument 2192 parameters from when MMC is being used in raw mode 2193 (for falcon mode) 2194 2195 CONFIG_SPL_FS_LOAD_PAYLOAD_NAME 2196 Filename to read to load U-Boot when reading from filesystem 2197 2198 CONFIG_SPL_FS_LOAD_KERNEL_NAME 2199 Filename to read to load kernel uImage when reading 2200 from filesystem (for Falcon mode) 2201 2202 CONFIG_SPL_FS_LOAD_ARGS_NAME 2203 Filename to read to load kernel argument parameters 2204 when reading from filesystem (for Falcon mode) 2205 2206 CONFIG_SPL_MPC83XX_WAIT_FOR_NAND 2207 Set this for NAND SPL on PPC mpc83xx targets, so that 2208 start.S waits for the rest of the SPL to load before 2209 continuing (the hardware starts execution after just 2210 loading the first page rather than the full 4K). 2211 2212 CONFIG_SPL_SKIP_RELOCATE 2213 Avoid SPL relocation 2214 2215 CONFIG_SPL_NAND_IDENT 2216 SPL uses the chip ID list to identify the NAND flash. 2217 Requires CONFIG_SPL_NAND_BASE. 2218 2219 CONFIG_SPL_UBI 2220 Support for a lightweight UBI (fastmap) scanner and 2221 loader 2222 2223 CONFIG_SPL_NAND_RAW_ONLY 2224 Support to boot only raw u-boot.bin images. Use this only 2225 if you need to save space. 2226 2227 CONFIG_SPL_COMMON_INIT_DDR 2228 Set for common ddr init with serial presence detect in 2229 SPL binary. 2230 2231 CONFIG_SYS_NAND_5_ADDR_CYCLE, CONFIG_SYS_NAND_PAGE_COUNT, 2232 CONFIG_SYS_NAND_PAGE_SIZE, CONFIG_SYS_NAND_OOBSIZE, 2233 CONFIG_SYS_NAND_BLOCK_SIZE, CONFIG_SYS_NAND_BAD_BLOCK_POS, 2234 CONFIG_SYS_NAND_ECCPOS, CONFIG_SYS_NAND_ECCSIZE, 2235 CONFIG_SYS_NAND_ECCBYTES 2236 Defines the size and behavior of the NAND that SPL uses 2237 to read U-Boot 2238 2239 CONFIG_SYS_NAND_U_BOOT_OFFS 2240 Location in NAND to read U-Boot from 2241 2242 CONFIG_SYS_NAND_U_BOOT_DST 2243 Location in memory to load U-Boot to 2244 2245 CONFIG_SYS_NAND_U_BOOT_SIZE 2246 Size of image to load 2247 2248 CONFIG_SYS_NAND_U_BOOT_START 2249 Entry point in loaded image to jump to 2250 2251 CONFIG_SYS_NAND_HW_ECC_OOBFIRST 2252 Define this if you need to first read the OOB and then the 2253 data. This is used, for example, on davinci platforms. 2254 2255 CONFIG_SPL_RAM_DEVICE 2256 Support for running image already present in ram, in SPL binary 2257 2258 CONFIG_SPL_PAD_TO 2259 Image offset to which the SPL should be padded before appending 2260 the SPL payload. By default, this is defined as 2261 CONFIG_SPL_MAX_SIZE, or 0 if CONFIG_SPL_MAX_SIZE is undefined. 2262 CONFIG_SPL_PAD_TO must be either 0, meaning to append the SPL 2263 payload without any padding, or >= CONFIG_SPL_MAX_SIZE. 2264 2265 CONFIG_SPL_TARGET 2266 Final target image containing SPL and payload. Some SPLs 2267 use an arch-specific makefile fragment instead, for 2268 example if more than one image needs to be produced. 2269 2270 CONFIG_SPL_FIT_PRINT 2271 Printing information about a FIT image adds quite a bit of 2272 code to SPL. So this is normally disabled in SPL. Use this 2273 option to re-enable it. This will affect the output of the 2274 bootm command when booting a FIT image. 2275 2276- TPL framework 2277 CONFIG_TPL 2278 Enable building of TPL globally. 2279 2280 CONFIG_TPL_PAD_TO 2281 Image offset to which the TPL should be padded before appending 2282 the TPL payload. By default, this is defined as 2283 CONFIG_SPL_MAX_SIZE, or 0 if CONFIG_SPL_MAX_SIZE is undefined. 2284 CONFIG_SPL_PAD_TO must be either 0, meaning to append the SPL 2285 payload without any padding, or >= CONFIG_SPL_MAX_SIZE. 2286 2287- Interrupt support (PPC): 2288 2289 There are common interrupt_init() and timer_interrupt() 2290 for all PPC archs. interrupt_init() calls interrupt_init_cpu() 2291 for CPU specific initialization. interrupt_init_cpu() 2292 should set decrementer_count to appropriate value. If 2293 CPU resets decrementer automatically after interrupt 2294 (ppc4xx) it should set decrementer_count to zero. 2295 timer_interrupt() calls timer_interrupt_cpu() for CPU 2296 specific handling. If board has watchdog / status_led 2297 / other_activity_monitor it works automatically from 2298 general timer_interrupt(). 2299 2300 2301Board initialization settings: 2302------------------------------ 2303 2304During Initialization u-boot calls a number of board specific functions 2305to allow the preparation of board specific prerequisites, e.g. pin setup 2306before drivers are initialized. To enable these callbacks the 2307following configuration macros have to be defined. Currently this is 2308architecture specific, so please check arch/your_architecture/lib/board.c 2309typically in board_init_f() and board_init_r(). 2310 2311- CONFIG_BOARD_EARLY_INIT_F: Call board_early_init_f() 2312- CONFIG_BOARD_EARLY_INIT_R: Call board_early_init_r() 2313- CONFIG_BOARD_LATE_INIT: Call board_late_init() 2314- CONFIG_BOARD_POSTCLK_INIT: Call board_postclk_init() 2315 2316Configuration Settings: 2317----------------------- 2318 2319- MEM_SUPPORT_64BIT_DATA: Defined automatically if compiled as 64-bit. 2320 Optionally it can be defined to support 64-bit memory commands. 2321 2322- CONFIG_SYS_LONGHELP: Defined when you want long help messages included; 2323 undefine this when you're short of memory. 2324 2325- CONFIG_SYS_HELP_CMD_WIDTH: Defined when you want to override the default 2326 width of the commands listed in the 'help' command output. 2327 2328- CONFIG_SYS_PROMPT: This is what U-Boot prints on the console to 2329 prompt for user input. 2330 2331- CONFIG_SYS_CBSIZE: Buffer size for input from the Console 2332 2333- CONFIG_SYS_PBSIZE: Buffer size for Console output 2334 2335- CONFIG_SYS_MAXARGS: max. Number of arguments accepted for monitor commands 2336 2337- CONFIG_SYS_BARGSIZE: Buffer size for Boot Arguments which are passed to 2338 the application (usually a Linux kernel) when it is 2339 booted 2340 2341- CONFIG_SYS_BAUDRATE_TABLE: 2342 List of legal baudrate settings for this board. 2343 2344- CONFIG_SYS_MEM_RESERVE_SECURE 2345 Only implemented for ARMv8 for now. 2346 If defined, the size of CONFIG_SYS_MEM_RESERVE_SECURE memory 2347 is substracted from total RAM and won't be reported to OS. 2348 This memory can be used as secure memory. A variable 2349 gd->arch.secure_ram is used to track the location. In systems 2350 the RAM base is not zero, or RAM is divided into banks, 2351 this variable needs to be recalcuated to get the address. 2352 2353- CONFIG_SYS_MEM_TOP_HIDE: 2354 If CONFIG_SYS_MEM_TOP_HIDE is defined in the board config header, 2355 this specified memory area will get subtracted from the top 2356 (end) of RAM and won't get "touched" at all by U-Boot. By 2357 fixing up gd->ram_size the Linux kernel should gets passed 2358 the now "corrected" memory size and won't touch it either. 2359 This should work for arch/ppc and arch/powerpc. Only Linux 2360 board ports in arch/powerpc with bootwrapper support that 2361 recalculate the memory size from the SDRAM controller setup 2362 will have to get fixed in Linux additionally. 2363 2364 This option can be used as a workaround for the 440EPx/GRx 2365 CHIP 11 errata where the last 256 bytes in SDRAM shouldn't 2366 be touched. 2367 2368 WARNING: Please make sure that this value is a multiple of 2369 the Linux page size (normally 4k). If this is not the case, 2370 then the end address of the Linux memory will be located at a 2371 non page size aligned address and this could cause major 2372 problems. 2373 2374- CONFIG_SYS_LOADS_BAUD_CHANGE: 2375 Enable temporary baudrate change while serial download 2376 2377- CONFIG_SYS_SDRAM_BASE: 2378 Physical start address of SDRAM. _Must_ be 0 here. 2379 2380- CONFIG_SYS_FLASH_BASE: 2381 Physical start address of Flash memory. 2382 2383- CONFIG_SYS_MONITOR_BASE: 2384 Physical start address of boot monitor code (set by 2385 make config files to be same as the text base address 2386 (CONFIG_SYS_TEXT_BASE) used when linking) - same as 2387 CONFIG_SYS_FLASH_BASE when booting from flash. 2388 2389- CONFIG_SYS_MONITOR_LEN: 2390 Size of memory reserved for monitor code, used to 2391 determine _at_compile_time_ (!) if the environment is 2392 embedded within the U-Boot image, or in a separate 2393 flash sector. 2394 2395- CONFIG_SYS_MALLOC_LEN: 2396 Size of DRAM reserved for malloc() use. 2397 2398- CONFIG_SYS_MALLOC_F_LEN 2399 Size of the malloc() pool for use before relocation. If 2400 this is defined, then a very simple malloc() implementation 2401 will become available before relocation. The address is just 2402 below the global data, and the stack is moved down to make 2403 space. 2404 2405 This feature allocates regions with increasing addresses 2406 within the region. calloc() is supported, but realloc() 2407 is not available. free() is supported but does nothing. 2408 The memory will be freed (or in fact just forgotten) when 2409 U-Boot relocates itself. 2410 2411- CONFIG_SYS_MALLOC_SIMPLE 2412 Provides a simple and small malloc() and calloc() for those 2413 boards which do not use the full malloc in SPL (which is 2414 enabled with CONFIG_SYS_SPL_MALLOC_START). 2415 2416- CONFIG_SYS_NONCACHED_MEMORY: 2417 Size of non-cached memory area. This area of memory will be 2418 typically located right below the malloc() area and mapped 2419 uncached in the MMU. This is useful for drivers that would 2420 otherwise require a lot of explicit cache maintenance. For 2421 some drivers it's also impossible to properly maintain the 2422 cache. For example if the regions that need to be flushed 2423 are not a multiple of the cache-line size, *and* padding 2424 cannot be allocated between the regions to align them (i.e. 2425 if the HW requires a contiguous array of regions, and the 2426 size of each region is not cache-aligned), then a flush of 2427 one region may result in overwriting data that hardware has 2428 written to another region in the same cache-line. This can 2429 happen for example in network drivers where descriptors for 2430 buffers are typically smaller than the CPU cache-line (e.g. 2431 16 bytes vs. 32 or 64 bytes). 2432 2433 Non-cached memory is only supported on 32-bit ARM at present. 2434 2435- CONFIG_SYS_BOOTM_LEN: 2436 Normally compressed uImages are limited to an 2437 uncompressed size of 8 MBytes. If this is not enough, 2438 you can define CONFIG_SYS_BOOTM_LEN in your board config file 2439 to adjust this setting to your needs. 2440 2441- CONFIG_SYS_BOOTMAPSZ: 2442 Maximum size of memory mapped by the startup code of 2443 the Linux kernel; all data that must be processed by 2444 the Linux kernel (bd_info, boot arguments, FDT blob if 2445 used) must be put below this limit, unless "bootm_low" 2446 environment variable is defined and non-zero. In such case 2447 all data for the Linux kernel must be between "bootm_low" 2448 and "bootm_low" + CONFIG_SYS_BOOTMAPSZ. The environment 2449 variable "bootm_mapsize" will override the value of 2450 CONFIG_SYS_BOOTMAPSZ. If CONFIG_SYS_BOOTMAPSZ is undefined, 2451 then the value in "bootm_size" will be used instead. 2452 2453- CONFIG_SYS_BOOT_RAMDISK_HIGH: 2454 Enable initrd_high functionality. If defined then the 2455 initrd_high feature is enabled and the bootm ramdisk subcommand 2456 is enabled. 2457 2458- CONFIG_SYS_BOOT_GET_CMDLINE: 2459 Enables allocating and saving kernel cmdline in space between 2460 "bootm_low" and "bootm_low" + BOOTMAPSZ. 2461 2462- CONFIG_SYS_BOOT_GET_KBD: 2463 Enables allocating and saving a kernel copy of the bd_info in 2464 space between "bootm_low" and "bootm_low" + BOOTMAPSZ. 2465 2466- CONFIG_SYS_MAX_FLASH_BANKS: 2467 Max number of Flash memory banks 2468 2469- CONFIG_SYS_MAX_FLASH_SECT: 2470 Max number of sectors on a Flash chip 2471 2472- CONFIG_SYS_FLASH_ERASE_TOUT: 2473 Timeout for Flash erase operations (in ms) 2474 2475- CONFIG_SYS_FLASH_WRITE_TOUT: 2476 Timeout for Flash write operations (in ms) 2477 2478- CONFIG_SYS_FLASH_LOCK_TOUT 2479 Timeout for Flash set sector lock bit operation (in ms) 2480 2481- CONFIG_SYS_FLASH_UNLOCK_TOUT 2482 Timeout for Flash clear lock bits operation (in ms) 2483 2484- CONFIG_SYS_FLASH_PROTECTION 2485 If defined, hardware flash sectors protection is used 2486 instead of U-Boot software protection. 2487 2488- CONFIG_SYS_DIRECT_FLASH_TFTP: 2489 2490 Enable TFTP transfers directly to flash memory; 2491 without this option such a download has to be 2492 performed in two steps: (1) download to RAM, and (2) 2493 copy from RAM to flash. 2494 2495 The two-step approach is usually more reliable, since 2496 you can check if the download worked before you erase 2497 the flash, but in some situations (when system RAM is 2498 too limited to allow for a temporary copy of the 2499 downloaded image) this option may be very useful. 2500 2501- CONFIG_SYS_FLASH_CFI: 2502 Define if the flash driver uses extra elements in the 2503 common flash structure for storing flash geometry. 2504 2505- CONFIG_FLASH_CFI_DRIVER 2506 This option also enables the building of the cfi_flash driver 2507 in the drivers directory 2508 2509- CONFIG_FLASH_CFI_MTD 2510 This option enables the building of the cfi_mtd driver 2511 in the drivers directory. The driver exports CFI flash 2512 to the MTD layer. 2513 2514- CONFIG_SYS_FLASH_USE_BUFFER_WRITE 2515 Use buffered writes to flash. 2516 2517- CONFIG_FLASH_SPANSION_S29WS_N 2518 s29ws-n MirrorBit flash has non-standard addresses for buffered 2519 write commands. 2520 2521- CONFIG_SYS_FLASH_QUIET_TEST 2522 If this option is defined, the common CFI flash doesn't 2523 print it's warning upon not recognized FLASH banks. This 2524 is useful, if some of the configured banks are only 2525 optionally available. 2526 2527- CONFIG_FLASH_SHOW_PROGRESS 2528 If defined (must be an integer), print out countdown 2529 digits and dots. Recommended value: 45 (9..1) for 80 2530 column displays, 15 (3..1) for 40 column displays. 2531 2532- CONFIG_FLASH_VERIFY 2533 If defined, the content of the flash (destination) is compared 2534 against the source after the write operation. An error message 2535 will be printed when the contents are not identical. 2536 Please note that this option is useless in nearly all cases, 2537 since such flash programming errors usually are detected earlier 2538 while unprotecting/erasing/programming. Please only enable 2539 this option if you really know what you are doing. 2540 2541- CONFIG_SYS_RX_ETH_BUFFER: 2542 Defines the number of Ethernet receive buffers. On some 2543 Ethernet controllers it is recommended to set this value 2544 to 8 or even higher (EEPRO100 or 405 EMAC), since all 2545 buffers can be full shortly after enabling the interface 2546 on high Ethernet traffic. 2547 Defaults to 4 if not defined. 2548 2549- CONFIG_ENV_MAX_ENTRIES 2550 2551 Maximum number of entries in the hash table that is used 2552 internally to store the environment settings. The default 2553 setting is supposed to be generous and should work in most 2554 cases. This setting can be used to tune behaviour; see 2555 lib/hashtable.c for details. 2556 2557- CONFIG_ENV_FLAGS_LIST_DEFAULT 2558- CONFIG_ENV_FLAGS_LIST_STATIC 2559 Enable validation of the values given to environment variables when 2560 calling env set. Variables can be restricted to only decimal, 2561 hexadecimal, or boolean. If CONFIG_CMD_NET is also defined, 2562 the variables can also be restricted to IP address or MAC address. 2563 2564 The format of the list is: 2565 type_attribute = [s|d|x|b|i|m] 2566 access_attribute = [a|r|o|c] 2567 attributes = type_attribute[access_attribute] 2568 entry = variable_name[:attributes] 2569 list = entry[,list] 2570 2571 The type attributes are: 2572 s - String (default) 2573 d - Decimal 2574 x - Hexadecimal 2575 b - Boolean ([1yYtT|0nNfF]) 2576 i - IP address 2577 m - MAC address 2578 2579 The access attributes are: 2580 a - Any (default) 2581 r - Read-only 2582 o - Write-once 2583 c - Change-default 2584 2585 - CONFIG_ENV_FLAGS_LIST_DEFAULT 2586 Define this to a list (string) to define the ".flags" 2587 environment variable in the default or embedded environment. 2588 2589 - CONFIG_ENV_FLAGS_LIST_STATIC 2590 Define this to a list (string) to define validation that 2591 should be done if an entry is not found in the ".flags" 2592 environment variable. To override a setting in the static 2593 list, simply add an entry for the same variable name to the 2594 ".flags" variable. 2595 2596 If CONFIG_REGEX is defined, the variable_name above is evaluated as a 2597 regular expression. This allows multiple variables to define the same 2598 flags without explicitly listing them for each variable. 2599 2600The following definitions that deal with the placement and management 2601of environment data (variable area); in general, we support the 2602following configurations: 2603 2604- CONFIG_BUILD_ENVCRC: 2605 2606 Builds up envcrc with the target environment so that external utils 2607 may easily extract it and embed it in final U-Boot images. 2608 2609BE CAREFUL! The first access to the environment happens quite early 2610in U-Boot initialization (when we try to get the setting of for the 2611console baudrate). You *MUST* have mapped your NVRAM area then, or 2612U-Boot will hang. 2613 2614Please note that even with NVRAM we still use a copy of the 2615environment in RAM: we could work on NVRAM directly, but we want to 2616keep settings there always unmodified except somebody uses "saveenv" 2617to save the current settings. 2618 2619BE CAREFUL! For some special cases, the local device can not use 2620"saveenv" command. For example, the local device will get the 2621environment stored in a remote NOR flash by SRIO or PCIE link, 2622but it can not erase, write this NOR flash by SRIO or PCIE interface. 2623 2624- CONFIG_NAND_ENV_DST 2625 2626 Defines address in RAM to which the nand_spl code should copy the 2627 environment. If redundant environment is used, it will be copied to 2628 CONFIG_NAND_ENV_DST + CONFIG_ENV_SIZE. 2629 2630Please note that the environment is read-only until the monitor 2631has been relocated to RAM and a RAM copy of the environment has been 2632created; also, when using EEPROM you will have to use env_get_f() 2633until then to read environment variables. 2634 2635The environment is protected by a CRC32 checksum. Before the monitor 2636is relocated into RAM, as a result of a bad CRC you will be working 2637with the compiled-in default environment - *silently*!!! [This is 2638necessary, because the first environment variable we need is the 2639"baudrate" setting for the console - if we have a bad CRC, we don't 2640have any device yet where we could complain.] 2641 2642Note: once the monitor has been relocated, then it will complain if 2643the default environment is used; a new CRC is computed as soon as you 2644use the "saveenv" command to store a valid environment. 2645 2646- CONFIG_SYS_FAULT_ECHO_LINK_DOWN: 2647 Echo the inverted Ethernet link state to the fault LED. 2648 2649 Note: If this option is active, then CONFIG_SYS_FAULT_MII_ADDR 2650 also needs to be defined. 2651 2652- CONFIG_SYS_FAULT_MII_ADDR: 2653 MII address of the PHY to check for the Ethernet link state. 2654 2655- CONFIG_NS16550_MIN_FUNCTIONS: 2656 Define this if you desire to only have use of the NS16550_init 2657 and NS16550_putc functions for the serial driver located at 2658 drivers/serial/ns16550.c. This option is useful for saving 2659 space for already greatly restricted images, including but not 2660 limited to NAND_SPL configurations. 2661 2662- CONFIG_DISPLAY_BOARDINFO 2663 Display information about the board that U-Boot is running on 2664 when U-Boot starts up. The board function checkboard() is called 2665 to do this. 2666 2667- CONFIG_DISPLAY_BOARDINFO_LATE 2668 Similar to the previous option, but display this information 2669 later, once stdio is running and output goes to the LCD, if 2670 present. 2671 2672- CONFIG_BOARD_SIZE_LIMIT: 2673 Maximum size of the U-Boot image. When defined, the 2674 build system checks that the actual size does not 2675 exceed it. 2676 2677Low Level (hardware related) configuration options: 2678--------------------------------------------------- 2679 2680- CONFIG_SYS_CACHELINE_SIZE: 2681 Cache Line Size of the CPU. 2682 2683- CONFIG_SYS_CCSRBAR_DEFAULT: 2684 Default (power-on reset) physical address of CCSR on Freescale 2685 PowerPC SOCs. 2686 2687- CONFIG_SYS_CCSRBAR: 2688 Virtual address of CCSR. On a 32-bit build, this is typically 2689 the same value as CONFIG_SYS_CCSRBAR_DEFAULT. 2690 2691- CONFIG_SYS_CCSRBAR_PHYS: 2692 Physical address of CCSR. CCSR can be relocated to a new 2693 physical address, if desired. In this case, this macro should 2694 be set to that address. Otherwise, it should be set to the 2695 same value as CONFIG_SYS_CCSRBAR_DEFAULT. For example, CCSR 2696 is typically relocated on 36-bit builds. It is recommended 2697 that this macro be defined via the _HIGH and _LOW macros: 2698 2699 #define CONFIG_SYS_CCSRBAR_PHYS ((CONFIG_SYS_CCSRBAR_PHYS_HIGH 2700 * 1ull) << 32 | CONFIG_SYS_CCSRBAR_PHYS_LOW) 2701 2702- CONFIG_SYS_CCSRBAR_PHYS_HIGH: 2703 Bits 33-36 of CONFIG_SYS_CCSRBAR_PHYS. This value is typically 2704 either 0 (32-bit build) or 0xF (36-bit build). This macro is 2705 used in assembly code, so it must not contain typecasts or 2706 integer size suffixes (e.g. "ULL"). 2707 2708- CONFIG_SYS_CCSRBAR_PHYS_LOW: 2709 Lower 32-bits of CONFIG_SYS_CCSRBAR_PHYS. This macro is 2710 used in assembly code, so it must not contain typecasts or 2711 integer size suffixes (e.g. "ULL"). 2712 2713- CONFIG_SYS_CCSR_DO_NOT_RELOCATE: 2714 If this macro is defined, then CONFIG_SYS_CCSRBAR_PHYS will be 2715 forced to a value that ensures that CCSR is not relocated. 2716 2717- CONFIG_IDE_AHB: 2718 Most IDE controllers were designed to be connected with PCI 2719 interface. Only few of them were designed for AHB interface. 2720 When software is doing ATA command and data transfer to 2721 IDE devices through IDE-AHB controller, some additional 2722 registers accessing to these kind of IDE-AHB controller 2723 is required. 2724 2725- CONFIG_SYS_IMMR: Physical address of the Internal Memory. 2726 DO NOT CHANGE unless you know exactly what you're 2727 doing! (11-4) [MPC8xx systems only] 2728 2729- CONFIG_SYS_INIT_RAM_ADDR: 2730 2731 Start address of memory area that can be used for 2732 initial data and stack; please note that this must be 2733 writable memory that is working WITHOUT special 2734 initialization, i. e. you CANNOT use normal RAM which 2735 will become available only after programming the 2736 memory controller and running certain initialization 2737 sequences. 2738 2739 U-Boot uses the following memory types: 2740 - MPC8xx: IMMR (internal memory of the CPU) 2741 2742- CONFIG_SYS_GBL_DATA_OFFSET: 2743 2744 Offset of the initial data structure in the memory 2745 area defined by CONFIG_SYS_INIT_RAM_ADDR. Usually 2746 CONFIG_SYS_GBL_DATA_OFFSET is chosen such that the initial 2747 data is located at the end of the available space 2748 (sometimes written as (CONFIG_SYS_INIT_RAM_SIZE - 2749 GENERATED_GBL_DATA_SIZE), and the initial stack is just 2750 below that area (growing from (CONFIG_SYS_INIT_RAM_ADDR + 2751 CONFIG_SYS_GBL_DATA_OFFSET) downward. 2752 2753 Note: 2754 On the MPC824X (or other systems that use the data 2755 cache for initial memory) the address chosen for 2756 CONFIG_SYS_INIT_RAM_ADDR is basically arbitrary - it must 2757 point to an otherwise UNUSED address space between 2758 the top of RAM and the start of the PCI space. 2759 2760- CONFIG_SYS_SCCR: System Clock and reset Control Register (15-27) 2761 2762- CONFIG_SYS_OR_TIMING_SDRAM: 2763 SDRAM timing 2764 2765- CONFIG_SYS_MAMR_PTA: 2766 periodic timer for refresh 2767 2768- FLASH_BASE0_PRELIM, FLASH_BASE1_PRELIM, CONFIG_SYS_REMAP_OR_AM, 2769 CONFIG_SYS_PRELIM_OR_AM, CONFIG_SYS_OR_TIMING_FLASH, CONFIG_SYS_OR0_REMAP, 2770 CONFIG_SYS_OR0_PRELIM, CONFIG_SYS_BR0_PRELIM, CONFIG_SYS_OR1_REMAP, CONFIG_SYS_OR1_PRELIM, 2771 CONFIG_SYS_BR1_PRELIM: 2772 Memory Controller Definitions: BR0/1 and OR0/1 (FLASH) 2773 2774- SDRAM_BASE2_PRELIM, SDRAM_BASE3_PRELIM, SDRAM_MAX_SIZE, 2775 CONFIG_SYS_OR_TIMING_SDRAM, CONFIG_SYS_OR2_PRELIM, CONFIG_SYS_BR2_PRELIM, 2776 CONFIG_SYS_OR3_PRELIM, CONFIG_SYS_BR3_PRELIM: 2777 Memory Controller Definitions: BR2/3 and OR2/3 (SDRAM) 2778 2779- CONFIG_SYS_SRIO: 2780 Chip has SRIO or not 2781 2782- CONFIG_SRIO1: 2783 Board has SRIO 1 port available 2784 2785- CONFIG_SRIO2: 2786 Board has SRIO 2 port available 2787 2788- CONFIG_SRIO_PCIE_BOOT_MASTER 2789 Board can support master function for Boot from SRIO and PCIE 2790 2791- CONFIG_SYS_SRIOn_MEM_VIRT: 2792 Virtual Address of SRIO port 'n' memory region 2793 2794- CONFIG_SYS_SRIOn_MEM_PHYxS: 2795 Physical Address of SRIO port 'n' memory region 2796 2797- CONFIG_SYS_SRIOn_MEM_SIZE: 2798 Size of SRIO port 'n' memory region 2799 2800- CONFIG_SYS_NAND_BUSWIDTH_16BIT 2801 Defined to tell the NAND controller that the NAND chip is using 2802 a 16 bit bus. 2803 Not all NAND drivers use this symbol. 2804 Example of drivers that use it: 2805 - drivers/mtd/nand/raw/ndfc.c 2806 - drivers/mtd/nand/raw/mxc_nand.c 2807 2808- CONFIG_SYS_NDFC_EBC0_CFG 2809 Sets the EBC0_CFG register for the NDFC. If not defined 2810 a default value will be used. 2811 2812- CONFIG_SPD_EEPROM 2813 Get DDR timing information from an I2C EEPROM. Common 2814 with pluggable memory modules such as SODIMMs 2815 2816 SPD_EEPROM_ADDRESS 2817 I2C address of the SPD EEPROM 2818 2819- CONFIG_SYS_SPD_BUS_NUM 2820 If SPD EEPROM is on an I2C bus other than the first 2821 one, specify here. Note that the value must resolve 2822 to something your driver can deal with. 2823 2824- CONFIG_SYS_DDR_RAW_TIMING 2825 Get DDR timing information from other than SPD. Common with 2826 soldered DDR chips onboard without SPD. DDR raw timing 2827 parameters are extracted from datasheet and hard-coded into 2828 header files or board specific files. 2829 2830- CONFIG_FSL_DDR_INTERACTIVE 2831 Enable interactive DDR debugging. See doc/README.fsl-ddr. 2832 2833- CONFIG_FSL_DDR_SYNC_REFRESH 2834 Enable sync of refresh for multiple controllers. 2835 2836- CONFIG_FSL_DDR_BIST 2837 Enable built-in memory test for Freescale DDR controllers. 2838 2839- CONFIG_SYS_83XX_DDR_USES_CS0 2840 Only for 83xx systems. If specified, then DDR should 2841 be configured using CS0 and CS1 instead of CS2 and CS3. 2842 2843- CONFIG_RMII 2844 Enable RMII mode for all FECs. 2845 Note that this is a global option, we can't 2846 have one FEC in standard MII mode and another in RMII mode. 2847 2848- CONFIG_CRC32_VERIFY 2849 Add a verify option to the crc32 command. 2850 The syntax is: 2851 2852 => crc32 -v <address> <count> <crc32> 2853 2854 Where address/count indicate a memory area 2855 and crc32 is the correct crc32 which the 2856 area should have. 2857 2858- CONFIG_LOOPW 2859 Add the "loopw" memory command. This only takes effect if 2860 the memory commands are activated globally (CONFIG_CMD_MEMORY). 2861 2862- CONFIG_CMD_MX_CYCLIC 2863 Add the "mdc" and "mwc" memory commands. These are cyclic 2864 "md/mw" commands. 2865 Examples: 2866 2867 => mdc.b 10 4 500 2868 This command will print 4 bytes (10,11,12,13) each 500 ms. 2869 2870 => mwc.l 100 12345678 10 2871 This command will write 12345678 to address 100 all 10 ms. 2872 2873 This only takes effect if the memory commands are activated 2874 globally (CONFIG_CMD_MEMORY). 2875 2876- CONFIG_SKIP_LOWLEVEL_INIT 2877 [ARM, NDS32, MIPS, RISC-V only] If this variable is defined, then certain 2878 low level initializations (like setting up the memory 2879 controller) are omitted and/or U-Boot does not 2880 relocate itself into RAM. 2881 2882 Normally this variable MUST NOT be defined. The only 2883 exception is when U-Boot is loaded (to RAM) by some 2884 other boot loader or by a debugger which performs 2885 these initializations itself. 2886 2887- CONFIG_SKIP_LOWLEVEL_INIT_ONLY 2888 [ARM926EJ-S only] This allows just the call to lowlevel_init() 2889 to be skipped. The normal CP15 init (such as enabling the 2890 instruction cache) is still performed. 2891 2892- CONFIG_SPL_BUILD 2893 Set when the currently-running compilation is for an artifact 2894 that will end up in the SPL (as opposed to the TPL or U-Boot 2895 proper). Code that needs stage-specific behavior should check 2896 this. 2897 2898- CONFIG_TPL_BUILD 2899 Set when the currently-running compilation is for an artifact 2900 that will end up in the TPL (as opposed to the SPL or U-Boot 2901 proper). Code that needs stage-specific behavior should check 2902 this. 2903 2904- CONFIG_SYS_MPC85XX_NO_RESETVEC 2905 Only for 85xx systems. If this variable is specified, the section 2906 .resetvec is not kept and the section .bootpg is placed in the 2907 previous 4k of the .text section. 2908 2909- CONFIG_ARCH_MAP_SYSMEM 2910 Generally U-Boot (and in particular the md command) uses 2911 effective address. It is therefore not necessary to regard 2912 U-Boot address as virtual addresses that need to be translated 2913 to physical addresses. However, sandbox requires this, since 2914 it maintains its own little RAM buffer which contains all 2915 addressable memory. This option causes some memory accesses 2916 to be mapped through map_sysmem() / unmap_sysmem(). 2917 2918- CONFIG_X86_RESET_VECTOR 2919 If defined, the x86 reset vector code is included. This is not 2920 needed when U-Boot is running from Coreboot. 2921 2922- CONFIG_SYS_NAND_NO_SUBPAGE_WRITE 2923 Option to disable subpage write in NAND driver 2924 driver that uses this: 2925 drivers/mtd/nand/raw/davinci_nand.c 2926 2927Freescale QE/FMAN Firmware Support: 2928----------------------------------- 2929 2930The Freescale QUICCEngine (QE) and Frame Manager (FMAN) both support the 2931loading of "firmware", which is encoded in the QE firmware binary format. 2932This firmware often needs to be loaded during U-Boot booting, so macros 2933are used to identify the storage device (NOR flash, SPI, etc) and the address 2934within that device. 2935 2936- CONFIG_SYS_FMAN_FW_ADDR 2937 The address in the storage device where the FMAN microcode is located. The 2938 meaning of this address depends on which CONFIG_SYS_QE_FMAN_FW_IN_xxx macro 2939 is also specified. 2940 2941- CONFIG_SYS_QE_FW_ADDR 2942 The address in the storage device where the QE microcode is located. The 2943 meaning of this address depends on which CONFIG_SYS_QE_FMAN_FW_IN_xxx macro 2944 is also specified. 2945 2946- CONFIG_SYS_QE_FMAN_FW_LENGTH 2947 The maximum possible size of the firmware. The firmware binary format 2948 has a field that specifies the actual size of the firmware, but it 2949 might not be possible to read any part of the firmware unless some 2950 local storage is allocated to hold the entire firmware first. 2951 2952- CONFIG_SYS_QE_FMAN_FW_IN_NOR 2953 Specifies that QE/FMAN firmware is located in NOR flash, mapped as 2954 normal addressable memory via the LBC. CONFIG_SYS_FMAN_FW_ADDR is the 2955 virtual address in NOR flash. 2956 2957- CONFIG_SYS_QE_FMAN_FW_IN_NAND 2958 Specifies that QE/FMAN firmware is located in NAND flash. 2959 CONFIG_SYS_FMAN_FW_ADDR is the offset within NAND flash. 2960 2961- CONFIG_SYS_QE_FMAN_FW_IN_MMC 2962 Specifies that QE/FMAN firmware is located on the primary SD/MMC 2963 device. CONFIG_SYS_FMAN_FW_ADDR is the byte offset on that device. 2964 2965- CONFIG_SYS_QE_FMAN_FW_IN_REMOTE 2966 Specifies that QE/FMAN firmware is located in the remote (master) 2967 memory space. CONFIG_SYS_FMAN_FW_ADDR is a virtual address which 2968 can be mapped from slave TLB->slave LAW->slave SRIO or PCIE outbound 2969 window->master inbound window->master LAW->the ucode address in 2970 master's memory space. 2971 2972Freescale Layerscape Management Complex Firmware Support: 2973--------------------------------------------------------- 2974The Freescale Layerscape Management Complex (MC) supports the loading of 2975"firmware". 2976This firmware often needs to be loaded during U-Boot booting, so macros 2977are used to identify the storage device (NOR flash, SPI, etc) and the address 2978within that device. 2979 2980- CONFIG_FSL_MC_ENET 2981 Enable the MC driver for Layerscape SoCs. 2982 2983Freescale Layerscape Debug Server Support: 2984------------------------------------------- 2985The Freescale Layerscape Debug Server Support supports the loading of 2986"Debug Server firmware" and triggering SP boot-rom. 2987This firmware often needs to be loaded during U-Boot booting. 2988 2989- CONFIG_SYS_MC_RSV_MEM_ALIGN 2990 Define alignment of reserved memory MC requires 2991 2992Reproducible builds 2993------------------- 2994 2995In order to achieve reproducible builds, timestamps used in the U-Boot build 2996process have to be set to a fixed value. 2997 2998This is done using the SOURCE_DATE_EPOCH environment variable. 2999SOURCE_DATE_EPOCH is to be set on the build host's shell, not as a configuration 3000option for U-Boot or an environment variable in U-Boot.
3001 3002SOURCE_DATE_EPOCH should be set to a number of seconds since the epoch, in UTC. 3003 3004Building the Software: 3005====================== 3006 3007Building U-Boot has been tested in several native build environments 3008and in many different cross environments. Of course we cannot support 3009all possibly existing versions of cross development tools in all 3010(potentially obsolete) versions. In case of tool chain problems we 3011recommend to use the ELDK (see https://www.denx.de/wiki/DULG/ELDK) 3012which is extensively used to build and test U-Boot. 3013 3014If you are not using a native environment, it is assumed that you 3015have GNU cross compiling tools available in your path. In this case, 3016you must set the environment variable CROSS_COMPILE in your shell. 3017Note that no changes to the Makefile or any other source files are 3018necessary. For example using the ELDK on a 4xx CPU, please enter: 3019 3020 $ CROSS_COMPILE=ppc_4xx- 3021 $ export CROSS_COMPILE 3022 3023U-Boot is intended to be simple to build. After installing the 3024sources you must configure U-Boot for one specific board type. This 3025is done by typing: 3026 3027 make NAME_defconfig 3028 3029where "NAME_defconfig" is the name of one of the existing configu- 3030rations; see configs/*_defconfig for supported names. 3031 3032Note: for some boards special configuration names may exist; check if 3033 additional information is available from the board vendor; for 3034 instance, the TQM823L systems are available without (standard) 3035 or with LCD support. You can select such additional "features" 3036 when choosing the configuration, i. e. 3037 3038 make TQM823L_defconfig 3039 - will configure for a plain TQM823L, i. e. no LCD support 3040 3041 make TQM823L_LCD_defconfig 3042 - will configure for a TQM823L with U-Boot console on LCD 3043 3044 etc. 3045 3046 3047Finally, type "make all", and you should get some working U-Boot 3048images ready for download to / installation on your system: 3049 3050- "u-boot.bin" is a raw binary image 3051- "u-boot" is an image in ELF binary format 3052- "u-boot.srec" is in Motorola S-Record format 3053 3054By default the build is performed locally and the objects are saved 3055in the source directory. One of the two methods can be used to change 3056this behavior and build U-Boot to some external directory: 3057 30581. Add O= to the make command line invocations: 3059 3060 make O=/tmp/build distclean 3061 make O=/tmp/build NAME_defconfig 3062 make O=/tmp/build all 3063 30642. Set environment variable KBUILD_OUTPUT to point to the desired location: 3065 3066 export KBUILD_OUTPUT=/tmp/build 3067 make distclean 3068 make NAME_defconfig 3069 make all 3070 3071Note that the command line "O=" setting overrides the KBUILD_OUTPUT environment 3072variable. 3073 3074User specific CPPFLAGS, AFLAGS and CFLAGS can be passed to the compiler by 3075setting the according environment variables KCPPFLAGS, KAFLAGS and KCFLAGS. 3076For example to treat all compiler warnings as errors: 3077 3078 make KCFLAGS=-Werror 3079 3080Please be aware that the Makefiles assume you are using GNU make, so 3081for instance on NetBSD you might need to use "gmake" instead of 3082native "make". 3083 3084 3085If the system board that you have is not listed, then you will need 3086to port U-Boot to your hardware platform. To do this, follow these 3087steps: 3088 30891. Create a new directory to hold your board specific code. Add any 3090 files you need. In your board directory, you will need at least 3091 the "Makefile" and a "<board>.c". 30922. Create a new configuration file "include/configs/<board>.h" for 3093 your board. 30943. If you're porting U-Boot to a new CPU, then also create a new 3095 directory to hold your CPU specific code. Add any files you need. 30964. Run "make <board>_defconfig" with your new name. 30975. Type "make", and you should get a working "u-boot.srec" file 3098 to be installed on your target system. 30996. Debug and solve any problems that might arise. 3100 [Of course, this last step is much harder than it sounds.] 3101 3102 3103Testing of U-Boot Modifications, Ports to New Hardware, etc.: 3104============================================================== 3105 3106If you have modified U-Boot sources (for instance added a new board 3107or support for new devices, a new CPU, etc.) you are expected to 3108provide feedback to the other developers. The feedback normally takes 3109the form of a "patch", i.e. a context diff against a certain (latest 3110official or latest in the git repository) version of U-Boot sources. 3111 3112But before you submit such a patch, please verify that your modifi- 3113cation did not break existing code. At least make sure that *ALL* of 3114the supported boards compile WITHOUT ANY compiler warnings. To do so, 3115just run the buildman script (tools/buildman/buildman), which will 3116configure and build U-Boot for ALL supported system. Be warned, this 3117will take a while. Please see the buildman README, or run 'buildman -H' 3118for documentation. 3119 3120 3121See also "U-Boot Porting Guide" below. 3122 3123 3124Monitor Commands - Overview: 3125============================ 3126 3127go - start application at address 'addr' 3128run - run commands in an environment variable 3129bootm - boot application image from memory 3130bootp - boot image via network using BootP/TFTP protocol 3131bootz - boot zImage from memory 3132tftpboot- boot image via network using TFTP protocol 3133 and env variables "ipaddr" and "serverip" 3134 (and eventually "gatewayip") 3135tftpput - upload a file via network using TFTP protocol 3136rarpboot- boot image via network using RARP/TFTP protocol 3137diskboot- boot from IDE devicebootd - boot default, i.e., run 'bootcmd' 3138loads - load S-Record file over serial line 3139loadb - load binary file over serial line (kermit mode) 3140md - memory display 3141mm - memory modify (auto-incrementing) 3142nm - memory modify (constant address) 3143mw - memory write (fill) 3144ms - memory search 3145cp - memory copy 3146cmp - memory compare 3147crc32 - checksum calculation 3148i2c - I2C sub-system 3149sspi - SPI utility commands 3150base - print or set address offset 3151printenv- print environment variables 3152pwm - control pwm channels 3153setenv - set environment variables 3154saveenv - save environment variables to persistent storage 3155protect - enable or disable FLASH write protection 3156erase - erase FLASH memory 3157flinfo - print FLASH memory information 3158nand - NAND memory operations (see doc/README.nand) 3159bdinfo - print Board Info structure 3160iminfo - print header information for application image 3161coninfo - print console devices and informations 3162ide - IDE sub-system 3163loop - infinite loop on address range 3164loopw - infinite write loop on address range 3165mtest - simple RAM test 3166icache - enable or disable instruction cache 3167dcache - enable or disable data cache 3168reset - Perform RESET of the CPU 3169echo - echo args to console 3170version - print monitor version 3171help - print online help 3172? - alias for 'help' 3173 3174 3175Monitor Commands - Detailed Description: 3176======================================== 3177 3178TODO. 3179 3180For now: just type "help <command>". 3181 3182 3183Environment Variables: 3184====================== 3185 3186U-Boot supports user configuration using Environment Variables which 3187can be made persistent by saving to Flash memory. 3188 3189Environment Variables are set using "setenv", printed using 3190"printenv", and saved to Flash using "saveenv". Using "setenv" 3191without a value can be used to delete a variable from the 3192environment. As long as you don't save the environment you are 3193working with an in-memory copy. In case the Flash area containing the 3194environment is erased by accident, a default environment is provided. 3195 3196Some configuration options can be set using Environment Variables. 3197 3198List of environment variables (most likely not complete): 3199 3200 baudrate - see CONFIG_BAUDRATE 3201 3202 bootdelay - see CONFIG_BOOTDELAY 3203 3204 bootcmd - see CONFIG_BOOTCOMMAND 3205 3206 bootargs - Boot arguments when booting an RTOS image 3207 3208 bootfile - Name of the image to load with TFTP 3209 3210 bootm_low - Memory range available for image processing in the bootm 3211 command can be restricted. This variable is given as 3212 a hexadecimal number and defines lowest address allowed 3213 for use by the bootm command. See also "bootm_size" 3214 environment variable. Address defined by "bootm_low" is 3215 also the base of the initial memory mapping for the Linux 3216 kernel -- see the description of CONFIG_SYS_BOOTMAPSZ and 3217 bootm_mapsize. 3218 3219 bootm_mapsize - Size of the initial memory mapping for the Linux kernel. 3220 This variable is given as a hexadecimal number and it 3221 defines the size of the memory region starting at base 3222 address bootm_low that is accessible by the Linux kernel 3223 during early boot. If unset, CONFIG_SYS_BOOTMAPSZ is used 3224 as the default value if it is defined, and bootm_size is 3225 used otherwise. 3226 3227 bootm_size - Memory range available for image processing in the bootm 3228 command can be restricted. This variable is given as 3229 a hexadecimal number and defines the size of the region 3230 allowed for use by the bootm command. See also "bootm_low" 3231 environment variable. 3232 3233 bootstopkeysha256, bootdelaykey, bootstopkey - See README.autoboot 3234 3235 updatefile - Location of the software update file on a TFTP server, used 3236 by the automatic software update feature. Please refer to 3237 documentation in doc/README.update for more details. 3238 3239 autoload - if set to "no" (any string beginning with 'n'), 3240 "bootp" will just load perform a lookup of the 3241 configuration from the BOOTP server, but not try to 3242 load any image using TFTP 3243 3244 autostart - if set to "yes", an image loaded using the "bootp", 3245 "rarpboot", "tftpboot" or "diskboot" commands will 3246 be automatically started (by internally calling 3247 "bootm") 3248 3249 If set to "no", a standalone image passed to the 3250 "bootm" command will be copied to the load address 3251 (and eventually uncompressed), but NOT be started. 3252 This can be used to load and uncompress arbitrary 3253 data. 3254 3255 fdt_high - if set this restricts the maximum address that the 3256 flattened device tree will be copied into upon boot. 3257 For example, if you have a system with 1 GB memory 3258 at physical address 0x10000000, while Linux kernel 3259 only recognizes the first 704 MB as low memory, you 3260 may need to set fdt_high as 0x3C000000 to have the 3261 device tree blob be copied to the maximum address 3262 of the 704 MB low memory, so that Linux kernel can 3263 access it during the boot procedure. 3264 3265 If this is set to the special value 0xFFFFFFFF then 3266 the fdt will not be copied at all on boot. For this 3267 to work it must reside in writable memory, have 3268 sufficient padding on the end of it for u-boot to 3269 add the information it needs into it, and the memory 3270 must be accessible by the kernel. 3271 3272 fdtcontroladdr- if set this is the address of the control flattened 3273 device tree used by U-Boot when CONFIG_OF_CONTROL is 3274 defined. 3275 3276 i2cfast - (PPC405GP|PPC405EP only) 3277 if set to 'y' configures Linux I2C driver for fast 3278 mode (400kHZ). This environment variable is used in 3279 initialization code. So, for changes to be effective 3280 it must be saved and board must be reset. 3281 3282 initrd_high - restrict positioning of initrd images: 3283 If this variable is not set, initrd images will be 3284 copied to the highest possible address in RAM; this 3285 is usually what you want since it allows for 3286 maximum initrd size. If for some reason you want to 3287 make sure that the initrd image is loaded below the 3288 CONFIG_SYS_BOOTMAPSZ limit, you can set this environment 3289 variable to a value of "no" or "off" or "0". 3290 Alternatively, you can set it to a maximum upper 3291 address to use (U-Boot will still check that it 3292 does not overwrite the U-Boot stack and data). 3293 3294 For instance, when you have a system with 16 MB 3295 RAM, and want to reserve 4 MB from use by Linux, 3296 you can do this by adding "mem=12M" to the value of 3297 the "bootargs" variable. However, now you must make 3298 sure that the initrd image is placed in the first 3299 12 MB as well - this can be done with 3300 3301 setenv initrd_high 00c00000 3302 3303 If you set initrd_high to 0xFFFFFFFF, this is an 3304 indication to U-Boot that all addresses are legal 3305 for the Linux kernel, including addresses in flash 3306 memory. In this case U-Boot will NOT COPY the 3307 ramdisk at all. This may be useful to reduce the 3308 boot time on your system, but requires that this 3309 feature is supported by your Linux kernel. 3310 3311 ipaddr - IP address; needed for tftpboot command 3312 3313 loadaddr - Default load address for commands like "bootp", 3314 "rarpboot", "tftpboot", "loadb" or "diskboot" 3315 3316 loads_echo - see CONFIG_LOADS_ECHO 3317 3318 serverip - TFTP server IP address; needed for tftpboot command 3319 3320 bootretry - see CONFIG_BOOT_RETRY_TIME 3321 3322 bootdelaykey - see CONFIG_AUTOBOOT_DELAY_STR 3323 3324 bootstopkey - see CONFIG_AUTOBOOT_STOP_STR 3325 3326 ethprime - controls which interface is used first. 3327 3328 ethact - controls which interface is currently active. 3329 For example you can do the following 3330 3331 => setenv ethact FEC 3332 => ping 192.168.0.1 # traffic sent on FEC 3333 => setenv ethact SCC 3334 => ping 10.0.0.1 # traffic sent on SCC 3335 3336 ethrotate - When set to "no" U-Boot does not go through all 3337 available network interfaces. 3338 It just stays at the currently selected interface. 3339 3340 netretry - When set to "no" each network operation will 3341 either succeed or fail without retrying. 3342 When set to "once" the network operation will 3343 fail when all the available network interfaces 3344 are tried once without success. 3345 Useful on scripts which control the retry operation 3346 themselves. 3347 3348 npe_ucode - set load address for the NPE microcode 3349 3350 silent_linux - If set then Linux will be told to boot silently, by 3351 changing the console to be empty. If "yes" it will be 3352 made silent. If "no" it will not be made silent. If 3353 unset, then it will be made silent if the U-Boot console 3354 is silent. 3355 3356 tftpsrcp - If this is set, the value is used for TFTP's 3357 UDP source port. 3358 3359 tftpdstp - If this is set, the value is used for TFTP's UDP 3360 destination port instead of the Well Know Port 69. 3361 3362 tftpblocksize - Block size to use for TFTP transfers; if not set, 3363 we use the TFTP server's default block size 3364 3365 tftptimeout - Retransmission timeout for TFTP packets (in milli- 3366 seconds, minimum value is 1000 = 1 second). Defines 3367 when a packet is considered to be lost so it has to 3368 be retransmitted. The default is 5000 = 5 seconds. 3369 Lowering this value may make downloads succeed 3370 faster in networks with high packet loss rates or 3371 with unreliable TFTP servers. 3372 3373 tftptimeoutcountmax - maximum count of TFTP timeouts (no 3374 unit, minimum value = 0). Defines how many timeouts 3375 can happen during a single file transfer before that 3376 transfer is aborted. The default is 10, and 0 means 3377 'no timeouts allowed'. Increasing this value may help 3378 downloads succeed with high packet loss rates, or with 3379 unreliable TFTP servers or client hardware. 3380 3381 tftpwindowsize - if this is set, the value is used for TFTP's 3382 window size as described by RFC 7440. 3383 This means the count of blocks we can receive before 3384 sending ack to server. 3385 3386 vlan - When set to a value < 4095 the traffic over 3387 Ethernet is encapsulated/received over 802.1q 3388 VLAN tagged frames. 3389 3390 bootpretryperiod - Period during which BOOTP/DHCP sends retries. 3391 Unsigned value, in milliseconds. If not set, the period will 3392 be either the default (28000), or a value based on 3393 CONFIG_NET_RETRY_COUNT, if defined. This value has 3394 precedence over the valu based on CONFIG_NET_RETRY_COUNT. 3395 3396 memmatches - Number of matches found by the last 'ms' command, in hex 3397 3398 memaddr - Address of the last match found by the 'ms' command, in hex, 3399 or 0 if none 3400 3401 mempos - Index position of the last match found by the 'ms' command, 3402 in units of the size (.b, .w, .l) of the search 3403 3404 zbootbase - (x86 only) Base address of the bzImage 'setup' block 3405 3406 zbootaddr - (x86 only) Address of the loaded bzImage, typically 3407 BZIMAGE_LOAD_ADDR which is 0x100000 3408 3409The following image location variables contain the location of images 3410used in booting. The "Image" column gives the role of the image and is 3411not an environment variable name. The other columns are environment 3412variable names. "File Name" gives the name of the file on a TFTP 3413server, "RAM Address" gives the location in RAM the image will be 3414loaded to, and "Flash Location" gives the image's address in NOR 3415flash or offset in NAND flash. 3416 3417*Note* - these variables don't have to be defined for all boards, some 3418boards currently use other variables for these purposes, and some 3419boards use these variables for other purposes. 3420 3421Image File Name RAM Address Flash Location 3422----- --------- ----------- -------------- 3423u-boot u-boot u-boot_addr_r u-boot_addr 3424Linux kernel bootfile kernel_addr_r kernel_addr 3425device tree blob fdtfile fdt_addr_r fdt_addr 3426ramdisk ramdiskfile ramdisk_addr_r ramdisk_addr 3427 3428The following environment variables may be used and automatically 3429updated by the network boot commands ("bootp" and "rarpboot"), 3430depending the information provided by your boot server: 3431 3432 bootfile - see above 3433 dnsip - IP address of your Domain Name Server 3434 dnsip2 - IP address of your secondary Domain Name Server 3435 gatewayip - IP address of the Gateway (Router) to use 3436 hostname - Target hostname 3437 ipaddr - see above 3438 netmask - Subnet Mask 3439 rootpath - Pathname of the root filesystem on the NFS server 3440 serverip - see above 3441 3442 3443There are two special Environment Variables: 3444 3445 serial# - contains hardware identification information such 3446 as type string and/or serial number 3447 ethaddr - Ethernet address 3448 3449These variables can be set only once (usually during manufacturing of 3450the board). U-Boot refuses to delete or overwrite these variables 3451once they have been set once. 3452 3453 3454Further special Environment Variables: 3455 3456 ver - Contains the U-Boot version string as printed 3457 with the "version" command. This variable is 3458 readonly (see CONFIG_VERSION_VARIABLE). 3459 3460 3461Please note that changes to some configuration parameters may take 3462only effect after the next boot (yes, that's just like Windoze :-). 3463 3464 3465Callback functions for environment variables: 3466--------------------------------------------- 3467 3468For some environment variables, the behavior of u-boot needs to change 3469when their values are changed. This functionality allows functions to 3470be associated with arbitrary variables. On creation, overwrite, or 3471deletion, the callback will provide the opportunity for some side 3472effect to happen or for the change to be rejected. 3473 3474The callbacks are named and associated with a function using the 3475U_BOOT_ENV_CALLBACK macro in your board or driver code. 3476 3477These callbacks are associated with variables in one of two ways. The 3478static list can be added to by defining CONFIG_ENV_CALLBACK_LIST_STATIC 3479in the board configuration to a string that defines a list of 3480associations. The list must be in the following format: 3481 3482 entry = variable_name[:callback_name] 3483 list = entry[,list] 3484 3485If the callback name is not specified, then the callback is deleted. 3486Spaces are also allowed anywhere in the list. 3487 3488Callbacks can also be associated by defining the ".callbacks" variable 3489with the same list format above. Any association in ".callbacks" will 3490override any association in the static list. You can define 3491CONFIG_ENV_CALLBACK_LIST_DEFAULT to a list (string) to define the 3492".callbacks" environment variable in the default or embedded environment. 3493 3494If CONFIG_REGEX is defined, the variable_name above is evaluated as a 3495regular expression. This allows multiple variables to be connected to 3496the same callback without explicitly listing them all out. 3497 3498The signature of the callback functions is: 3499 3500 int callback(const char *name, const char *value, enum env_op op, int flags) 3501 3502* name - changed environment variable 3503* value - new value of the environment variable 3504* op - operation (create, overwrite, or delete) 3505* flags - attributes of the environment variable change, see flags H_* in 3506 include/search.h 3507 3508The return value is 0 if the variable change is accepted and 1 otherwise. 3509 3510 3511Note for Redundant Ethernet Interfaces: 3512======================================= 3513 3514Some boards come with redundant Ethernet interfaces; U-Boot supports 3515such configurations and is capable of automatic selection of a 3516"working" interface when needed. MAC assignment works as follows: 3517 3518Network interfaces are numbered eth0, eth1, eth2, ... Corresponding 3519MAC addresses can be stored in the environment as "ethaddr" (=>eth0), 3520"eth1addr" (=>eth1), "eth2addr", ... 3521 3522If the network interface stores some valid MAC address (for instance 3523in SROM), this is used as default address if there is NO correspon- 3524ding setting in the environment; if the corresponding environment 3525variable is set, this overrides the settings in the card; that means: 3526 3527o If the SROM has a valid MAC address, and there is no address in the 3528 environment, the SROM's address is used. 3529 3530o If there is no valid address in the SROM, and a definition in the 3531 environment exists, then the value from the environment variable is 3532 used. 3533 3534o If both the SROM and the environment contain a MAC address, and 3535 both addresses are the same, this MAC address is used. 3536 3537o If both the SROM and the environment contain a MAC address, and the 3538 addresses differ, the value from the environment is used and a 3539 warning is printed. 3540 3541o If neither SROM nor the environment contain a MAC address, an error 3542 is raised. If CONFIG_NET_RANDOM_ETHADDR is defined, then in this case 3543 a random, locally-assigned MAC is used. 3544 3545If Ethernet drivers implement the 'write_hwaddr' function, valid MAC addresses 3546will be programmed into hardware as part of the initialization process. This 3547may be skipped by setting the appropriate 'ethmacskip' environment variable. 3548The naming convention is as follows: 3549"ethmacskip" (=>eth0), "eth1macskip" (=>eth1) etc. 3550 3551Image Formats: 3552============== 3553 3554U-Boot is capable of booting (and performing other auxiliary operations on) 3555images in two formats: 3556 3557New uImage format (FIT) 3558----------------------- 3559 3560Flexible and powerful format based on Flattened Image Tree -- FIT (similar 3561to Flattened Device Tree). It allows the use of images with multiple 3562components (several kernels, ramdisks, etc.), with contents protected by 3563SHA1, MD5 or CRC32. More details are found in the doc/uImage.FIT directory. 3564 3565 3566Old uImage format 3567----------------- 3568 3569Old image format is based on binary files which can be basically anything, 3570preceded by a special header; see the definitions in include/image.h for 3571details; basically, the header defines the following image properties: 3572 3573* Target Operating System (Provisions for OpenBSD, NetBSD, FreeBSD, 3574 4.4BSD, Linux, SVR4, Esix, Solaris, Irix, SCO, Dell, NCR, VxWorks, 3575 LynxOS, pSOS, QNX, RTEMS, INTEGRITY; 3576 Currently supported: Linux, NetBSD, VxWorks, QNX, RTEMS, LynxOS, 3577 INTEGRITY). 3578* Target CPU Architecture (Provisions for Alpha, ARM, Intel x86, 3579 IA64, MIPS, NDS32, Nios II, PowerPC, IBM S390, SuperH, Sparc, Sparc 64 Bit; 3580 Currently supported: ARM, Intel x86, MIPS, NDS32, Nios II, PowerPC). 3581* Compression Type (uncompressed, gzip, bzip2) 3582* Load Address 3583* Entry Point 3584* Image Name 3585* Image Timestamp 3586 3587The header is marked by a special Magic Number, and both the header 3588and the data portions of the image are secured against corruption by 3589CRC32 checksums. 3590 3591 3592Linux Support: 3593============== 3594 3595Although U-Boot should support any OS or standalone application 3596easily, the main focus has always been on Linux during the design of 3597U-Boot. 3598 3599U-Boot includes many features that so far have been part of some 3600special "boot loader" code within the Linux kernel. Also, any 3601"initrd" images to be used are no longer part of one big Linux image; 3602instead, kernel and "initrd" are separate images. This implementation 3603serves several purposes: 3604 3605- the same features can be used for other OS or standalone 3606 applications (for instance: using compressed images to reduce the 3607 Flash memory footprint) 3608 3609- it becomes much easier to port new Linux kernel versions because 3610 lots of low-level, hardware dependent stuff are done by U-Boot 3611 3612- the same Linux kernel image can now be used with different "initrd" 3613 images; of course this also means that different kernel images can 3614 be run with the same "initrd". This makes testing easier (you don't 3615 have to build a new "zImage.initrd" Linux image when you just 3616 change a file in your "initrd"). Also, a field-upgrade of the 3617 software is easier now. 3618 3619 3620Linux HOWTO: 3621============ 3622 3623Porting Linux to U-Boot based systems: 3624--------------------------------------- 3625 3626U-Boot cannot save you from doing all the necessary modifications to 3627configure the Linux device drivers for use with your target hardware 3628(no, we don't intend to provide a full virtual machine interface to 3629Linux :-). 3630 3631But now you can ignore ALL boot loader code (in arch/powerpc/mbxboot). 3632 3633Just make sure your machine specific header file (for instance 3634include/asm-ppc/tqm8xx.h) includes the same definition of the Board 3635Information structure as we define in include/asm-<arch>/u-boot.h, 3636and make sure that your definition of IMAP_ADDR uses the same value 3637as your U-Boot configuration in CONFIG_SYS_IMMR. 3638 3639Note that U-Boot now has a driver model, a unified model for drivers. 3640If you are adding a new driver, plumb it into driver model. If there 3641is no uclass available, you are encouraged to create one. See 3642doc/driver-model. 3643 3644 3645Configuring the Linux kernel: 3646----------------------------- 3647 3648No specific requirements for U-Boot. Make sure you have some root 3649device (initial ramdisk, NFS) for your target system. 3650 3651 3652Building a Linux Image: 3653----------------------- 3654 3655With U-Boot, "normal" build targets like "zImage" or "bzImage" are 3656not used. If you use recent kernel source, a new build target 3657"uImage" will exist which automatically builds an image usable by 3658U-Boot. Most older kernels also have support for a "pImage" target, 3659which was introduced for our predecessor project PPCBoot and uses a 3660100% compatible format. 3661 3662Example: 3663 3664 make TQM850L_defconfig 3665 make oldconfig 3666 make dep 3667 make uImage 3668 3669The "uImage" build target uses a special tool (in 'tools/mkimage') to 3670encapsulate a compressed Linux kernel image with header information, 3671CRC32 checksum etc. for use with U-Boot. This is what we are doing: 3672 3673* build a standard "vmlinux" kernel image (in ELF binary format): 3674 3675* convert the kernel into a raw binary image: 3676 3677 ${CROSS_COMPILE}-objcopy -O binary \ 3678 -R .note -R .comment \ 3679 -S vmlinux linux.bin 3680 3681* compress the binary image: 3682 3683 gzip -9 linux.bin 3684 3685* package compressed binary image for U-Boot: 3686 3687 mkimage -A ppc -O linux -T kernel -C gzip \ 3688 -a 0 -e 0 -n "Linux Kernel Image" \ 3689 -d linux.bin.gz uImage 3690 3691 3692The "mkimage" tool can also be used to create ramdisk images for use 3693with U-Boot, either separated from the Linux kernel image, or 3694combined into one file. "mkimage" encapsulates the images with a 64 3695byte header containing information about target architecture, 3696operating system, image type, compression method, entry points, time 3697stamp, CRC32 checksums, etc. 3698 3699"mkimage" can be called in two ways: to verify existing images and 3700print the header information, or to build new images. 3701 3702In the first form (with "-l" option) mkimage lists the information 3703contained in the header of an existing U-Boot image; this includes 3704checksum verification: 3705 3706 tools/mkimage -l image 3707 -l ==> list image header information 3708 3709The second form (with "-d" option) is used to build a U-Boot image 3710from a "data file" which is used as image payload: 3711 3712 tools/mkimage -A arch -O os -T type -C comp -a addr -e ep \ 3713 -n name -d data_file image 3714 -A ==> set architecture to 'arch' 3715 -O ==> set operating system to 'os' 3716 -T ==> set image type to 'type' 3717 -C ==> set compression type 'comp' 3718 -a ==> set load address to 'addr' (hex) 3719 -e ==> set entry point to 'ep' (hex) 3720 -n ==> set image name to 'name' 3721 -d ==> use image data from 'datafile' 3722 3723Right now, all Linux kernels for PowerPC systems use the same load 3724address (0x00000000), but the entry point address depends on the 3725kernel version: 3726 3727- 2.2.x kernels have the entry point at 0x0000000C, 3728- 2.3.x and later kernels have the entry point at 0x00000000. 3729 3730So a typical call to build a U-Boot image would read: 3731 3732 -> tools/mkimage -n '2.4.4 kernel for TQM850L' \ 3733 > -A ppc -O linux -T kernel -C gzip -a 0 -e 0 \ 3734 > -d /opt/elsk/ppc_8xx/usr/src/linux-2.4.4/arch/powerpc/coffboot/vmlinux.gz \ 3735 > examples/uImage.TQM850L 3736 Image Name: 2.4.4 kernel for TQM850L 3737 Created: Wed Jul 19 02:34:59 2000 3738 Image Type: PowerPC Linux Kernel Image (gzip compressed) 3739 Data Size: 335725 Bytes = 327.86 kB = 0.32 MB 3740 Load Address: 0x00000000 3741 Entry Point: 0x00000000 3742 3743To verify the contents of the image (or check for corruption): 3744 3745 -> tools/mkimage -l examples/uImage.TQM850L 3746 Image Name: 2.4.4 kernel for TQM850L 3747 Created: Wed Jul 19 02:34:59 2000 3748 Image Type: PowerPC Linux Kernel Image (gzip compressed) 3749 Data Size: 335725 Bytes = 327.86 kB = 0.32 MB 3750 Load Address: 0x00000000 3751 Entry Point: 0x00000000 3752 3753NOTE: for embedded systems where boot time is critical you can trade 3754speed for memory and install an UNCOMPRESSED image instead: this 3755needs more space in Flash, but boots much faster since it does not 3756need to be uncompressed: 3757 3758 -> gunzip /opt/elsk/ppc_8xx/usr/src/linux-2.4.4/arch/powerpc/coffboot/vmlinux.gz 3759 -> tools/mkimage -n '2.4.4 kernel for TQM850L' \ 3760 > -A ppc -O linux -T kernel -C none -a 0 -e 0 \ 3761 > -d /opt/elsk/ppc_8xx/usr/src/linux-2.4.4/arch/powerpc/coffboot/vmlinux \ 3762 > examples/uImage.TQM850L-uncompressed 3763 Image Name: 2.4.4 kernel for TQM850L 3764 Created: Wed Jul 19 02:34:59 2000 3765 Image Type: PowerPC Linux Kernel Image (uncompressed) 3766 Data Size: 792160 Bytes = 773.59 kB = 0.76 MB 3767 Load Address: 0x00000000 3768 Entry Point: 0x00000000 3769 3770 3771Similar you can build U-Boot images from a 'ramdisk.image.gz' file 3772when your kernel is intended to use an initial ramdisk: 3773 3774 -> tools/mkimage -n 'Simple Ramdisk Image' \ 3775 > -A ppc -O linux -T ramdisk -C gzip \ 3776 > -d /LinuxPPC/images/SIMPLE-ramdisk.image.gz examples/simple-initrd 3777 Image Name: Simple Ramdisk Image 3778 Created: Wed Jan 12 14:01:50 2000 3779 Image Type: PowerPC Linux RAMDisk Image (gzip compressed) 3780 Data Size: 566530 Bytes = 553.25 kB = 0.54 MB 3781 Load Address: 0x00000000 3782 Entry Point: 0x00000000 3783 3784The "dumpimage" tool can be used to disassemble or list the contents of images 3785built by mkimage. See dumpimage's help output (-h) for details. 3786 3787Installing a Linux Image: 3788------------------------- 3789 3790To downloading a U-Boot image over the serial (console) interface, 3791you must convert the image to S-Record format: 3792 3793 objcopy -I binary -O srec examples/image examples/image.srec 3794 3795The 'objcopy' does not understand the information in the U-Boot 3796image header, so the resulting S-Record file will be relative to 3797address 0x00000000. To load it to a given address, you need to 3798specify the target address as 'offset' parameter with the 'loads' 3799command. 3800 3801Example: install the image to address 0x40100000 (which on the 3802TQM8xxL is in the first Flash bank): 3803 3804 => erase 40100000 401FFFFF 3805 3806 .......... done 3807 Erased 8 sectors 3808 3809 => loads 40100000 3810 ## Ready for S-Record download ... 3811 ~>examples/image.srec 3812 1 2 3 4 5 6 7 8 9 10 11 12 13 ... 3813 ... 3814 15989 15990 15991 15992 3815 [file transfer complete] 3816 [connected] 3817 ## Start Addr = 0x00000000 3818 3819 3820You can check the success of the download using the 'iminfo' command; 3821this includes a checksum verification so you can be sure no data 3822corruption happened: 3823 3824 => imi 40100000 3825 3826 ## Checking Image at 40100000 ... 3827 Image Name: 2.2.13 for initrd on TQM850L 3828 Image Type: PowerPC Linux Kernel Image (gzip compressed) 3829 Data Size: 335725 Bytes = 327 kB = 0 MB 3830 Load Address: 00000000 3831 Entry Point: 0000000c 3832 Verifying Checksum ... OK 3833 3834 3835Boot Linux: 3836----------- 3837 3838The "bootm" command is used to boot an application that is stored in 3839memory (RAM or Flash). In case of a Linux kernel image, the contents 3840of the "bootargs" environment variable is passed to the kernel as 3841parameters. You can check and modify this variable using the 3842"printenv" and "setenv" commands: 3843 3844 3845 => printenv bootargs 3846 bootargs=root=/dev/ram 3847 3848 => setenv bootargs root=/dev/nfs rw nfsroot=10.0.0.2:/LinuxPPC nfsaddrs=10.0.0.99:10.0.0.2 3849 3850 => printenv bootargs 3851 bootargs=root=/dev/nfs rw nfsroot=10.0.0.2:/LinuxPPC nfsaddrs=10.0.0.99:10.0.0.2 3852 3853 => bootm 40020000 3854 ## Booting Linux kernel at 40020000 ... 3855 Image Name: 2.2.13 for NFS on TQM850L 3856 Image Type: PowerPC Linux Kernel Image (gzip compressed) 3857 Data Size: 381681 Bytes = 372 kB = 0 MB 3858 Load Address: 00000000 3859 Entry Point: 0000000c 3860 Verifying Checksum ... OK 3861 Uncompressing Kernel Image ... OK 3862 Linux version 2.2.13 (wd@denx.local.net) (gcc version 2.95.2 19991024 (release)) #1 Wed Jul 19 02:35:17 MEST 2000 3863 Boot arguments: root=/dev/nfs rw nfsroot=10.0.0.2:/LinuxPPC nfsaddrs=10.0.0.99:10.0.0.2 3864 time_init: decrementer frequency = 187500000/60 3865 Calibrating delay loop... 49.77 BogoMIPS 3866 Memory: 15208k available (700k kernel code, 444k data, 32k init) [c0000000,c1000000] 3867 ... 3868 3869If you want to boot a Linux kernel with initial RAM disk, you pass 3870the memory addresses of both the kernel and the initrd image (PPBCOOT 3871format!) to the "bootm" command: 3872 3873 => imi 40100000 40200000 3874 3875 ## Checking Image at 40100000 ... 3876 Image Name: 2.2.13 for initrd on TQM850L 3877 Image Type: PowerPC Linux Kernel Image (gzip compressed) 3878 Data Size: 335725 Bytes = 327 kB = 0 MB 3879 Load Address: 00000000 3880 Entry Point: 0000000c 3881 Verifying Checksum ... OK 3882 3883 ## Checking Image at 40200000 ... 3884 Image Name: Simple Ramdisk Image 3885 Image Type: PowerPC Linux RAMDisk Image (gzip compressed) 3886 Data Size: 566530 Bytes = 553 kB = 0 MB 3887 Load Address: 00000000 3888 Entry Point: 00000000 3889 Verifying Checksum ... OK 3890 3891 => bootm 40100000 40200000 3892 ## Booting Linux kernel at 40100000 ... 3893 Image Name: 2.2.13 for initrd on TQM850L 3894 Image Type: PowerPC Linux Kernel Image (gzip compressed) 3895 Data Size: 335725 Bytes = 327 kB = 0 MB 3896 Load Address: 00000000 3897 Entry Point: 0000000c 3898 Verifying Checksum ... OK 3899 Uncompressing Kernel Image ... OK 3900 ## Loading RAMDisk Image at 40200000 ... 3901 Image Name: Simple Ramdisk Image 3902 Image Type: PowerPC Linux RAMDisk Image (gzip compressed) 3903 Data Size: 566530 Bytes = 553 kB = 0 MB 3904 Load Address: 00000000 3905 Entry Point: 00000000 3906 Verifying Checksum ... OK 3907 Loading Ramdisk ... OK 3908 Linux version 2.2.13 (wd@denx.local.net) (gcc version 2.95.2 19991024 (release)) #1 Wed Jul 19 02:32:08 MEST 2000 3909 Boot arguments: root=/dev/ram 3910 time_init: decrementer frequency = 187500000/60 3911 Calibrating delay loop... 49.77 BogoMIPS 3912 ... 3913 RAMDISK: Compressed image found at block 0 3914 VFS: Mounted root (ext2 filesystem). 3915 3916 bash# 3917 3918Boot Linux and pass a flat device tree: 3919----------- 3920 3921First, U-Boot must be compiled with the appropriate defines. See the section 3922titled "Linux Kernel Interface" above for a more in depth explanation. The 3923following is an example of how to start a kernel and pass an updated 3924flat device tree: 3925 3926=> print oftaddr 3927oftaddr=0x300000 3928=> print oft 3929oft=oftrees/mpc8540ads.dtb 3930=> tftp $oftaddr $oft 3931Speed: 1000, full duplex 3932Using TSEC0 device 3933TFTP from server 192.168.1.1; our IP address is 192.168.1.101 3934Filename 'oftrees/mpc8540ads.dtb'. 3935Load address: 0x300000 3936Loading: # 3937done 3938Bytes transferred = 4106 (100a hex) 3939=> tftp $loadaddr $bootfile 3940Speed: 1000, full duplex 3941Using TSEC0 device 3942TFTP from server 192.168.1.1; our IP address is 192.168.1.2 3943Filename 'uImage'. 3944Load address: 0x200000 3945Loading:############ 3946done 3947Bytes transferred = 1029407 (fb51f hex) 3948=> print loadaddr 3949loadaddr=200000 3950=> print oftaddr 3951oftaddr=0x300000 3952=> bootm $loadaddr - $oftaddr 3953## Booting image at 00200000 ... 3954 Image Name: Linux-2.6.17-dirty 3955 Image Type: PowerPC Linux Kernel Image (gzip compressed) 3956 Data Size: 1029343 Bytes = 1005.2 kB 3957 Load Address: 00000000 3958 Entry Point: 00000000 3959 Verifying Checksum ... OK 3960 Uncompressing Kernel Image ... OK 3961Booting using flat device tree at 0x300000 3962Using MPC85xx ADS machine description 3963Memory CAM mapping: CAM0=256Mb, CAM1=256Mb, CAM2=0Mb residual: 0Mb 3964[snip] 3965 3966 3967More About U-Boot Image Types: 3968------------------------------ 3969 3970U-Boot supports the following image types: 3971 3972 "Standalone Programs" are directly runnable in the environment 3973 provided by U-Boot; it is expected that (if they behave 3974 well) you can continue to work in U-Boot after return from 3975 the Standalone Program. 3976 "OS Kernel Images" are usually images of some Embedded OS which 3977 will take over control completely. Usually these programs 3978 will install their own set of exception handlers, device 3979 drivers, set up the MMU, etc. - this means, that you cannot 3980 expect to re-enter U-Boot except by resetting the CPU. 3981 "RAMDisk Images" are more or less just data blocks, and their 3982 parameters (address, size) are passed to an OS kernel that is 3983 being started. 3984 "Multi-File Images" contain several images, typically an OS 3985 (Linux) kernel image and one or more data images like 3986 RAMDisks. This construct is useful for instance when you want 3987 to boot over the network using BOOTP etc., where the boot 3988 server provides just a single image file, but you want to get 3989 for instance an OS kernel and a RAMDisk image. 3990 3991 "Multi-File Images" start with a list of image sizes, each 3992 image size (in bytes) specified by an "uint32_t" in network 3993 byte order. This list is terminated by an "(uint32_t)0". 3994 Immediately after the terminating 0 follow the images, one by 3995 one, all aligned on "uint32_t" boundaries (size rounded up to 3996 a multiple of 4 bytes). 3997 3998 "Firmware Images" are binary images containing firmware (like 3999 U-Boot or FPGA images) which usually will be programmed to 4000 flash memory.
4001 4002 "Script files" are command sequences that will be executed by 4003 U-Boot's command interpreter; this feature is especially 4004 useful when you configure U-Boot to use a real shell (hush) 4005 as command interpreter. 4006 4007Booting the Linux zImage: 4008------------------------- 4009 4010On some platforms, it's possible to boot Linux zImage. This is done 4011using the "bootz" command. The syntax of "bootz" command is the same 4012as the syntax of "bootm" command. 4013 4014Note, defining the CONFIG_SUPPORT_RAW_INITRD allows user to supply 4015kernel with raw initrd images. The syntax is slightly different, the 4016address of the initrd must be augmented by it's size, in the following 4017format: "<initrd addres>:<initrd size>". 4018 4019 4020Standalone HOWTO: 4021================= 4022 4023One of the features of U-Boot is that you can dynamically load and 4024run "standalone" applications, which can use some resources of 4025U-Boot like console I/O functions or interrupt services. 4026 4027Two simple examples are included with the sources: 4028 4029"Hello World" Demo: 4030------------------- 4031 4032'examples/hello_world.c' contains a small "Hello World" Demo 4033application; it is automatically compiled when you build U-Boot. 4034It's configured to run at address 0x00040004, so you can play with it 4035like that: 4036 4037 => loads 4038 ## Ready for S-Record download ... 4039 ~>examples/hello_world.srec 4040 1 2 3 4 5 6 7 8 9 10 11 ... 4041 [file transfer complete] 4042 [connected] 4043 ## Start Addr = 0x00040004 4044 4045 => go 40004 Hello World! This is a test. 4046 ## Starting application at 0x00040004 ... 4047 Hello World 4048 argc = 7 4049 argv[0] = "40004" 4050 argv[1] = "Hello" 4051 argv[2] = "World!" 4052 argv[3] = "This" 4053 argv[4] = "is" 4054 argv[5] = "a" 4055 argv[6] = "test." 4056 argv[7] = "<NULL>" 4057 Hit any key to exit ... 4058 4059 ## Application terminated, rc = 0x0 4060 4061Another example, which demonstrates how to register a CPM interrupt 4062handler with the U-Boot code, can be found in 'examples/timer.c'. 4063Here, a CPM timer is set up to generate an interrupt every second. 4064The interrupt service routine is trivial, just printing a '.' 4065character, but this is just a demo program. The application can be 4066controlled by the following keys: 4067 4068 ? - print current values og the CPM Timer registers 4069 b - enable interrupts and start timer 4070 e - stop timer and disable interrupts 4071 q - quit application 4072 4073 => loads 4074 ## Ready for S-Record download ... 4075 ~>examples/timer.srec 4076 1 2 3 4 5 6 7 8 9 10 11 ... 4077 [file transfer complete] 4078 [connected] 4079 ## Start Addr = 0x00040004 4080 4081 => go 40004 4082 ## Starting application at 0x00040004 ... 4083 TIMERS=0xfff00980 4084 Using timer 1 4085 tgcr @ 0xfff00980, tmr @ 0xfff00990, trr @ 0xfff00994, tcr @ 0xfff00998, tcn @ 0xfff0099c, ter @ 0xfff009b0 4086 4087Hit 'b': 4088 [q, b, e, ?] Set interval 1000000 us 4089 Enabling timer 4090Hit '?': 4091 [q, b, e, ?] ........ 4092 tgcr=0x1, tmr=0xff1c, trr=0x3d09, tcr=0x0, tcn=0xef6, ter=0x0 4093Hit '?': 4094 [q, b, e, ?] . 4095 tgcr=0x1, tmr=0xff1c, trr=0x3d09, tcr=0x0, tcn=0x2ad4, ter=0x0 4096Hit '?': 4097 [q, b, e, ?] . 4098 tgcr=0x1, tmr=0xff1c, trr=0x3d09, tcr=0x0, tcn=0x1efc, ter=0x0 4099Hit '?': 4100 [q, b, e, ?] . 4101 tgcr=0x1, tmr=0xff1c, trr=0x3d09, tcr=0x0, tcn=0x169d, ter=0x0 4102Hit 'e': 4103 [q, b, e, ?] ...Stopping timer 4104Hit 'q': 4105 [q, b, e, ?] ## Application terminated, rc = 0x0 4106 4107 4108Minicom warning: 4109================ 4110 4111Over time, many people have reported problems when trying to use the 4112"minicom" terminal emulation program for serial download. I (wd) 4113consider minicom to be broken, and recommend not to use it. Under 4114Unix, I recommend to use C-Kermit for general purpose use (and 4115especially for kermit binary protocol download ("loadb" command), and 4116use "cu" for S-Record download ("loads" command). See 4117https://www.denx.de/wiki/view/DULG/SystemSetup#Section_4.3. 4118for help with kermit. 4119 4120 4121Nevertheless, if you absolutely want to use it try adding this 4122configuration to your "File transfer protocols" section: 4123 4124 Name Program Name U/D FullScr IO-Red. Multi 4125 X kermit /usr/bin/kermit -i -l %l -s Y U Y N N 4126 Y kermit /usr/bin/kermit -i -l %l -r N D Y N N 4127 4128 4129NetBSD Notes: 4130============= 4131 4132Starting at version 0.9.2, U-Boot supports NetBSD both as host 4133(build U-Boot) and target system (boots NetBSD/mpc8xx). 4134 4135Building requires a cross environment; it is known to work on 4136NetBSD/i386 with the cross-powerpc-netbsd-1.3 package (you will also 4137need gmake since the Makefiles are not compatible with BSD make). 4138Note that the cross-powerpc package does not install include files; 4139attempting to build U-Boot will fail because <machine/ansi.h> is 4140missing. This file has to be installed and patched manually: 4141 4142 # cd /usr/pkg/cross/powerpc-netbsd/include 4143 # mkdir powerpc 4144 # ln -s powerpc machine 4145 # cp /usr/src/sys/arch/powerpc/include/ansi.h powerpc/ansi.h 4146 # ${EDIT} powerpc/ansi.h ## must remove __va_list, _BSD_VA_LIST 4147 4148Native builds *don't* work due to incompatibilities between native 4149and U-Boot include files. 4150 4151Booting assumes that (the first part of) the image booted is a 4152stage-2 loader which in turn loads and then invokes the kernel 4153proper. Loader sources will eventually appear in the NetBSD source 4154tree (probably in sys/arc/mpc8xx/stand/u-boot_stage2/); in the 4155meantime, see ftp://ftp.denx.de/pub/u-boot/ppcboot_stage2.tar.gz 4156 4157 4158Implementation Internals: 4159========================= 4160 4161The following is not intended to be a complete description of every 4162implementation detail. However, it should help to understand the 4163inner workings of U-Boot and make it easier to port it to custom 4164hardware. 4165 4166 4167Initial Stack, Global Data: 4168--------------------------- 4169 4170The implementation of U-Boot is complicated by the fact that U-Boot 4171starts running out of ROM (flash memory), usually without access to 4172system RAM (because the memory controller is not initialized yet). 4173This means that we don't have writable Data or BSS segments, and BSS 4174is not initialized as zero. To be able to get a C environment working 4175at all, we have to allocate at least a minimal stack. Implementation 4176options for this are defined and restricted by the CPU used: Some CPU 4177models provide on-chip memory (like the IMMR area on MPC8xx and 4178MPC826x processors), on others (parts of) the data cache can be 4179locked as (mis-) used as memory, etc. 4180 4181 Chris Hallinan posted a good summary of these issues to the 4182 U-Boot mailing list: 4183 4184 Subject: RE: [U-Boot-Users] RE: More On Memory Bank x (nothingness)? 4185 From: "Chris Hallinan" <clh@net1plus.com> 4186 Date: Mon, 10 Feb 2003 16:43:46 -0500 (22:43 MET) 4187 ... 4188 4189 Correct me if I'm wrong, folks, but the way I understand it 4190 is this: Using DCACHE as initial RAM for Stack, etc, does not 4191 require any physical RAM backing up the cache. The cleverness 4192 is that the cache is being used as a temporary supply of 4193 necessary storage before the SDRAM controller is setup. It's 4194 beyond the scope of this list to explain the details, but you 4195 can see how this works by studying the cache architecture and 4196 operation in the architecture and processor-specific manuals. 4197 4198 OCM is On Chip Memory, which I believe the 405GP has 4K. It 4199 is another option for the system designer to use as an 4200 initial stack/RAM area prior to SDRAM being available. Either 4201 option should work for you. Using CS 4 should be fine if your 4202 board designers haven't used it for something that would 4203 cause you grief during the initial boot! It is frequently not 4204 used. 4205 4206 CONFIG_SYS_INIT_RAM_ADDR should be somewhere that won't interfere 4207 with your processor/board/system design. The default value 4208 you will find in any recent u-boot distribution in 4209 walnut.h should work for you. I'd set it to a value larger 4210 than your SDRAM module. If you have a 64MB SDRAM module, set 4211 it above 400_0000. Just make sure your board has no resources 4212 that are supposed to respond to that address! That code in 4213 start.S has been around a while and should work as is when 4214 you get the config right. 4215 4216 -Chris Hallinan 4217 DS4.COM, Inc. 4218 4219It is essential to remember this, since it has some impact on the C 4220code for the initialization procedures: 4221 4222* Initialized global data (data segment) is read-only. Do not attempt 4223 to write it. 4224 4225* Do not use any uninitialized global data (or implicitly initialized 4226 as zero data - BSS segment) at all - this is undefined, initiali- 4227 zation is performed later (when relocating to RAM). 4228 4229* Stack space is very limited. Avoid big data buffers or things like 4230 that. 4231 4232Having only the stack as writable memory limits means we cannot use 4233normal global data to share information between the code. But it 4234turned out that the implementation of U-Boot can be greatly 4235simplified by making a global data structure (gd_t) available to all 4236functions. We could pass a pointer to this data as argument to _all_ 4237functions, but this would bloat the code. Instead we use a feature of 4238the GCC compiler (Global Register Variables) to share the data: we 4239place a pointer (gd) to the global data into a register which we 4240reserve for this purpose. 4241 4242When choosing a register for such a purpose we are restricted by the 4243relevant (E)ABI specifications for the current architecture, and by 4244GCC's implementation. 4245 4246For PowerPC, the following registers have specific use: 4247 R1: stack pointer 4248 R2: reserved for system use 4249 R3-R4: parameter passing and return values 4250 R5-R10: parameter passing 4251 R13: small data area pointer 4252 R30: GOT pointer 4253 R31: frame pointer 4254 4255 (U-Boot also uses R12 as internal GOT pointer. r12 4256 is a volatile register so r12 needs to be reset when 4257 going back and forth between asm and C) 4258 4259 ==> U-Boot will use R2 to hold a pointer to the global data 4260 4261 Note: on PPC, we could use a static initializer (since the 4262 address of the global data structure is known at compile time), 4263 but it turned out that reserving a register results in somewhat 4264 smaller code - although the code savings are not that big (on 4265 average for all boards 752 bytes for the whole U-Boot image, 4266 624 text + 127 data). 4267 4268On ARM, the following registers are used: 4269 4270 R0: function argument word/integer result 4271 R1-R3: function argument word 4272 R9: platform specific 4273 R10: stack limit (used only if stack checking is enabled) 4274 R11: argument (frame) pointer 4275 R12: temporary workspace 4276 R13: stack pointer 4277 R14: link register 4278 R15: program counter 4279 4280 ==> U-Boot will use R9 to hold a pointer to the global data 4281 4282 Note: on ARM, only R_ARM_RELATIVE relocations are supported. 4283 4284On Nios II, the ABI is documented here: 4285 https://www.altera.com/literature/hb/nios2/n2cpu_nii51016.pdf 4286 4287 ==> U-Boot will use gp to hold a pointer to the global data 4288 4289 Note: on Nios II, we give "-G0" option to gcc and don't use gp 4290 to access small data sections, so gp is free. 4291 4292On NDS32, the following registers are used: 4293 4294 R0-R1: argument/return 4295 R2-R5: argument 4296 R15: temporary register for assembler 4297 R16: trampoline register 4298 R28: frame pointer (FP) 4299 R29: global pointer (GP) 4300 R30: link register (LP) 4301 R31: stack pointer (SP) 4302 PC: program counter (PC) 4303 4304 ==> U-Boot will use R10 to hold a pointer to the global data 4305 4306NOTE: DECLARE_GLOBAL_DATA_PTR must be used with file-global scope, 4307or current versions of GCC may "optimize" the code too much. 4308 4309On RISC-V, the following registers are used: 4310 4311 x0: hard-wired zero (zero) 4312 x1: return address (ra) 4313 x2: stack pointer (sp) 4314 x3: global pointer (gp) 4315 x4: thread pointer (tp) 4316 x5: link register (t0) 4317 x8: frame pointer (fp) 4318 x10-x11: arguments/return values (a0-1) 4319 x12-x17: arguments (a2-7) 4320 x28-31: temporaries (t3-6) 4321 pc: program counter (pc) 4322 4323 ==> U-Boot will use gp to hold a pointer to the global data 4324 4325Memory Management: 4326------------------ 4327 4328U-Boot runs in system state and uses physical addresses, i.e. the 4329MMU is not used either for address mapping nor for memory protection. 4330 4331The available memory is mapped to fixed addresses using the memory 4332controller. In this process, a contiguous block is formed for each 4333memory type (Flash, SDRAM, SRAM), even when it consists of several 4334physical memory banks. 4335 4336U-Boot is installed in the first 128 kB of the first Flash bank (on 4337TQM8xxL modules this is the range 0x40000000 ... 0x4001FFFF). After 4338booting and sizing and initializing DRAM, the code relocates itself 4339to the upper end of DRAM. Immediately below the U-Boot code some 4340memory is reserved for use by malloc() [see CONFIG_SYS_MALLOC_LEN 4341configuration setting]. Below that, a structure with global Board 4342Info data is placed, followed by the stack (growing downward). 4343 4344Additionally, some exception handler code is copied to the low 8 kB 4345of DRAM (0x00000000 ... 0x00001FFF). 4346 4347So a typical memory configuration with 16 MB of DRAM could look like 4348this: 4349 4350 0x0000 0000 Exception Vector code 4351 : 4352 0x0000 1FFF 4353 0x0000 2000 Free for Application Use 4354 : 4355 : 4356 4357 : 4358 : 4359 0x00FB FF20 Monitor Stack (Growing downward) 4360 0x00FB FFAC Board Info Data and permanent copy of global data 4361 0x00FC 0000 Malloc Arena 4362 : 4363 0x00FD FFFF 4364 0x00FE 0000 RAM Copy of Monitor Code 4365 ... eventually: LCD or video framebuffer 4366 ... eventually: pRAM (Protected RAM - unchanged by reset) 4367 0x00FF FFFF [End of RAM] 4368 4369 4370System Initialization: 4371---------------------- 4372 4373In the reset configuration, U-Boot starts at the reset entry point 4374(on most PowerPC systems at address 0x00000100). Because of the reset 4375configuration for CS0# this is a mirror of the on board Flash memory. 4376To be able to re-map memory U-Boot then jumps to its link address. 4377To be able to implement the initialization code in C, a (small!) 4378initial stack is set up in the internal Dual Ported RAM (in case CPUs 4379which provide such a feature like), or in a locked part of the data 4380cache. After that, U-Boot initializes the CPU core, the caches and 4381the SIU. 4382 4383Next, all (potentially) available memory banks are mapped using a 4384preliminary mapping. For example, we put them on 512 MB boundaries 4385(multiples of 0x20000000: SDRAM on 0x00000000 and 0x20000000, Flash 4386on 0x40000000 and 0x60000000, SRAM on 0x80000000). Then UPM A is 4387programmed for SDRAM access. Using the temporary configuration, a 4388simple memory test is run that determines the size of the SDRAM 4389banks. 4390 4391When there is more than one SDRAM bank, and the banks are of 4392different size, the largest is mapped first. For equal size, the first 4393bank (CS2#) is mapped first. The first mapping is always for address 43940x00000000, with any additional banks following immediately to create 4395contiguous memory starting from 0. 4396 4397Then, the monitor installs itself at the upper end of the SDRAM area 4398and allocates memory for use by malloc() and for the global Board 4399Info data; also, the exception vector code is copied to the low RAM 4400pages, and the final stack is set up. 4401 4402Only after this relocation will you have a "normal" C environment; 4403until that you are restricted in several ways, mostly because you are 4404running from ROM, and because the code will have to be relocated to a 4405new address in RAM. 4406 4407 4408U-Boot Porting Guide: 4409---------------------- 4410 4411[Based on messages by Jerry Van Baren in the U-Boot-Users mailing 4412list, October 2002] 4413 4414 4415int main(int argc, char *argv[]) 4416{ 4417 sighandler_t no_more_time; 4418 4419 signal(SIGALRM, no_more_time); 4420 alarm(PROJECT_DEADLINE - toSec (3 * WEEK)); 4421 4422 if (available_money > available_manpower) { 4423 Pay consultant to port U-Boot; 4424 return 0; 4425 } 4426 4427 Download latest U-Boot source; 4428 4429 Subscribe to u-boot mailing list; 4430 4431 if (clueless) 4432 email("Hi, I am new to U-Boot, how do I get started?"); 4433 4434 while (learning) { 4435 Read the README file in the top level directory; 4436 Read https://www.denx.de/wiki/bin/view/DULG/Manual; 4437 Read applicable doc/README.*; 4438 Read the source, Luke; 4439 /* find . -name "*.[chS]" | xargs grep -i <keyword> */ 4440 } 4441 4442 if (available_money > toLocalCurrency ($2500)) 4443 Buy a BDI3000; 4444 else 4445 Add a lot of aggravation and time; 4446 4447 if (a similar board exists) { /* hopefully... */ 4448 cp -a board/<similar> board/<myboard> 4449 cp include/configs/<similar>.h include/configs/<myboard>.h 4450 } else { 4451 Create your own board support subdirectory; 4452 Create your own board include/configs/<myboard>.h file; 4453 } 4454 Edit new board/<myboard> files 4455 Edit new include/configs/<myboard>.h 4456 4457 while (!accepted) { 4458 while (!running) { 4459 do { 4460 Add / modify source code; 4461 } until (compiles); 4462 Debug; 4463 if (clueless) 4464 email("Hi, I am having problems..."); 4465 } 4466 Send patch file to the U-Boot email list; 4467 if (reasonable critiques) 4468 Incorporate improvements from email list code review; 4469 else 4470 Defend code as written; 4471 } 4472 4473 return 0; 4474} 4475 4476void no_more_time (int sig) 4477{ 4478 hire_a_guru(); 4479} 4480 4481 4482Coding Standards: 4483----------------- 4484 4485All contributions to U-Boot should conform to the Linux kernel 4486coding style; see the kernel coding style guide at 4487https://www.kernel.org/doc/html/latest/process/coding-style.html, and the 4488script "scripts/Lindent" in your Linux kernel source directory. 4489 4490Source files originating from a different project (for example the 4491MTD subsystem) are generally exempt from these guidelines and are not 4492reformatted to ease subsequent migration to newer versions of those 4493sources. 4494 4495Please note that U-Boot is implemented in C (and to some small parts in 4496Assembler); no C++ is used, so please do not use C++ style comments (//) 4497in your code. 4498 4499Please also stick to the following formatting rules: 4500- remove any trailing white space 4501- use TAB characters for indentation and vertical alignment, not spaces 4502- make sure NOT to use DOS '\r\n' line feeds 4503- do not add more than 2 consecutive empty lines to source files 4504- do not add trailing empty lines to source files 4505 4506Submissions which do not conform to the standards may be returned 4507with a request to reformat the changes. 4508 4509 4510Submitting Patches: 4511------------------- 4512 4513Since the number of patches for U-Boot is growing, we need to 4514establish some rules. Submissions which do not conform to these rules 4515may be rejected, even when they contain important and valuable stuff. 4516 4517Please see https://www.denx.de/wiki/U-Boot/Patches for details. 4518 4519Patches shall be sent to the u-boot mailing list <u-boot@lists.denx.de>; 4520see https://lists.denx.de/listinfo/u-boot 4521 4522When you send a patch, please include the following information with 4523it: 4524 4525* For bug fixes: a description of the bug and how your patch fixes 4526 this bug. Please try to include a way of demonstrating that the 4527 patch actually fixes something. 4528 4529* For new features: a description of the feature and your 4530 implementation. 4531 4532* For major contributions, add a MAINTAINERS file with your 4533 information and associated file and directory references. 4534 4535* When you add support for a new board, don't forget to add a 4536 maintainer e-mail address to the boards.cfg file, too. 4537 4538* If your patch adds new configuration options, don't forget to 4539 document these in the README file. 4540 4541* The patch itself. If you are using git (which is *strongly* 4542 recommended) you can easily generate the patch using the 4543 "git format-patch". If you then use "git send-email" to send it to 4544 the U-Boot mailing list, you will avoid most of the common problems 4545 with some other mail clients. 4546 4547 If you cannot use git, use "diff -purN OLD NEW". If your version of 4548 diff does not support these options, then get the latest version of 4549 GNU diff. 4550 4551 The current directory when running this command shall be the parent 4552 directory of the U-Boot source tree (i. e. please make sure that 4553 your patch includes sufficient directory information for the 4554 affected files). 4555 4556 We prefer patches as plain text. MIME attachments are discouraged, 4557 and compressed attachments must not be used. 4558 4559* If one logical set of modifications affects or creates several 4560 files, all these changes shall be submitted in a SINGLE patch file. 4561 4562* Changesets that contain different, unrelated modifications shall be 4563 submitted as SEPARATE patches, one patch per changeset. 4564 4565 4566Notes: 4567 4568* Before sending the patch, run the buildman script on your patched 4569 source tree and make sure that no errors or warnings are reported 4570 for any of the boards. 4571 4572* Keep your modifications to the necessary minimum: A patch 4573 containing several unrelated changes or arbitrary reformats will be 4574 returned with a request to re-formatting / split it. 4575 4576* If you modify existing code, make sure that your new code does not 4577 add to the memory footprint of the code ;-) Small is beautiful! 4578 When adding new features, these should compile conditionally only 4579 (using #ifdef), and the resulting code with the new feature 4580 disabled must not need more memory than the old code without your 4581 modification. 4582 4583* Remember that there is a size limit of 100 kB per message on the 4584 u-boot mailing list. Bigger patches will be moderated. If they are 4585 reasonable and not too big, they will be acknowledged. But patches 4586 bigger than the size limit should be avoided. 4587