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/boot Support for images and booting 148/cmd U-Boot commands functions 149/common Misc architecture-independent functions 150/configs Board default configuration files 151/disk Code for disk drive partition handling 152/doc Documentation (a mix of ReST and READMEs) 153/drivers Device drivers 154/dts Makefile for building internal U-Boot fdt. 155/env Environment support 156/examples Example code for standalone applications, etc. 157/fs Filesystem code (cramfs, ext2, jffs2, etc.) 158/include Header Files 159/lib Library routines generic to all architectures 160/Licenses Various license files 161/net Networking code 162/post Power On Self Test 163/scripts Various build scripts and Makefiles 164/test Various unit test files 165/tools Tools to build and sign FIT images, etc. 166 167Software Configuration: 168======================= 169 170Configuration is usually done using C preprocessor defines; the 171rationale behind that is to avoid dead code whenever possible. 172 173There are two classes of configuration variables: 174 175* Configuration _OPTIONS_: 176 These are selectable by the user and have names beginning with 177 "CONFIG_". 178 179* Configuration _SETTINGS_: 180 These depend on the hardware etc. and should not be meddled with if 181 you don't know what you're doing; they have names beginning with 182 "CONFIG_SYS_". 183 184Previously, all configuration was done by hand, which involved creating 185symbolic links and editing configuration files manually. More recently, 186U-Boot has added the Kbuild infrastructure used by the Linux kernel, 187allowing you to use the "make menuconfig" command to configure your 188build. 189 190 191Selection of Processor Architecture and Board Type: 192--------------------------------------------------- 193 194For all supported boards there are ready-to-use default 195configurations available; just type "make <board_name>_defconfig". 196 197Example: For a TQM823L module type: 198 199 cd u-boot 200 make TQM823L_defconfig 201 202Note: If you're looking for the default configuration file for a board 203you're sure used to be there but is now missing, check the file 204doc/README.scrapyard for a list of no longer supported boards. 205 206Sandbox Environment: 207-------------------- 208 209U-Boot can be built natively to run on a Linux host using the 'sandbox' 210board. This allows feature development which is not board- or architecture- 211specific to be undertaken on a native platform. The sandbox is also used to 212run some of U-Boot's tests. 213 214See doc/arch/sandbox.rst for more details. 215 216 217Board Initialisation Flow: 218-------------------------- 219 220This is the intended start-up flow for boards. This should apply for both 221SPL and U-Boot proper (i.e. they both follow the same rules). 222 223Note: "SPL" stands for "Secondary Program Loader," which is explained in 224more detail later in this file. 225 226At present, SPL mostly uses a separate code path, but the function names 227and roles of each function are the same. Some boards or architectures 228may not conform to this. At least most ARM boards which use 229CONFIG_SPL_FRAMEWORK conform to this. 230 231Execution typically starts with an architecture-specific (and possibly 232CPU-specific) start.S file, such as: 233 234 - arch/arm/cpu/armv7/start.S 235 - arch/powerpc/cpu/mpc83xx/start.S 236 - arch/mips/cpu/start.S 237 238and so on. From there, three functions are called; the purpose and 239limitations of each of these functions are described below. 240 241lowlevel_init(): 242 - purpose: essential init to permit execution to reach board_init_f() 243 - no global_data or BSS 244 - there is no stack (ARMv7 may have one but it will soon be removed) 245 - must not set up SDRAM or use console 246 - must only do the bare minimum to allow execution to continue to 247 board_init_f() 248 - this is almost never needed 249 - return normally from this function 250 251board_init_f(): 252 - purpose: set up the machine ready for running board_init_r(): 253 i.e. SDRAM and serial UART 254 - global_data is available 255 - stack is in SRAM 256 - BSS is not available, so you cannot use global/static variables, 257 only stack variables and global_data 258 259 Non-SPL-specific notes: 260 - dram_init() is called to set up DRAM. If already done in SPL this 261 can do nothing 262 263 SPL-specific notes: 264 - you can override the entire board_init_f() function with your own 265 version as needed. 266 - preloader_console_init() can be called here in extremis 267 - should set up SDRAM, and anything needed to make the UART work 268 - there is no need to clear BSS, it will be done by crt0.S 269 - for specific scenarios on certain architectures an early BSS *can* 270 be made available (via CONFIG_SPL_EARLY_BSS by moving the clearing 271 of BSS prior to entering board_init_f()) but doing so is discouraged. 272 Instead it is strongly recommended to architect any code changes 273 or additions such to not depend on the availability of BSS during 274 board_init_f() as indicated in other sections of this README to 275 maintain compatibility and consistency across the entire code base. 276 - must return normally from this function (don't call board_init_r() 277 directly) 278 279Here the BSS is cleared. For SPL, if CONFIG_SPL_STACK_R is defined, then at 280this point the stack and global_data are relocated to below 281CONFIG_SPL_STACK_R_ADDR. For non-SPL, U-Boot is relocated to run at the top of 282memory. 283 284board_init_r(): 285 - purpose: main execution, common code 286 - global_data is available 287 - SDRAM is available 288 - BSS is available, all static/global variables can be used 289 - execution eventually continues to main_loop() 290 291 Non-SPL-specific notes: 292 - U-Boot is relocated to the top of memory and is now running from 293 there. 294 295 SPL-specific notes: 296 - stack is optionally in SDRAM, if CONFIG_SPL_STACK_R is defined and 297 CONFIG_SPL_STACK_R_ADDR points into SDRAM 298 - preloader_console_init() can be called here - typically this is 299 done by selecting CONFIG_SPL_BOARD_INIT and then supplying a 300 spl_board_init() function containing this call 301 - loads U-Boot or (in falcon mode) Linux 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_IFC_BE 469 Defines the IFC controller register space as Big Endian 470 471 CONFIG_SYS_FSL_IFC_LE 472 Defines the IFC controller register space as Little Endian 473 474 CONFIG_SYS_FSL_IFC_CLK_DIV 475 Defines divider of platform clock(clock input to IFC controller). 476 477 CONFIG_SYS_FSL_LBC_CLK_DIV 478 Defines divider of platform clock(clock input to eLBC controller). 479 480 CONFIG_SYS_FSL_DDR_BE 481 Defines the DDR controller register space as Big Endian 482 483 CONFIG_SYS_FSL_DDR_LE 484 Defines the DDR controller register space as Little Endian 485 486 CONFIG_SYS_FSL_DDR_SDRAM_BASE_PHY 487 Physical address from the view of DDR controllers. It is the 488 same as CONFIG_SYS_DDR_SDRAM_BASE for all Power SoCs. But 489 it could be different for ARM SoCs. 490 491 CONFIG_SYS_FSL_DDR_INTLV_256B 492 DDR controller interleaving on 256-byte. This is a special 493 interleaving mode, handled by Dickens for Freescale layerscape 494 SoCs with ARM core. 495 496 CONFIG_SYS_FSL_DDR_MAIN_NUM_CTRLS 497 Number of controllers used as main memory. 498 499 CONFIG_SYS_FSL_OTHER_DDR_NUM_CTRLS 500 Number of controllers used for other than main memory. 501 502 CONFIG_SYS_FSL_HAS_DP_DDR 503 Defines the SoC has DP-DDR used for DPAA. 504 505 CONFIG_SYS_FSL_SEC_BE 506 Defines the SEC controller register space as Big Endian 507 508 CONFIG_SYS_FSL_SEC_LE 509 Defines the SEC controller register space as Little Endian 510 511- MIPS CPU options: 512 CONFIG_SYS_INIT_SP_OFFSET 513 514 Offset relative to CONFIG_SYS_SDRAM_BASE for initial stack 515 pointer. This is needed for the temporary stack before 516 relocation. 517 518 CONFIG_XWAY_SWAP_BYTES 519 520 Enable compilation of tools/xway-swap-bytes needed for Lantiq 521 XWAY SoCs for booting from NOR flash. The U-Boot image needs to 522 be swapped if a flash programmer is used. 523 524- ARM options: 525 CONFIG_SYS_EXCEPTION_VECTORS_HIGH 526 527 Select high exception vectors of the ARM core, e.g., do not 528 clear the V bit of the c1 register of CP15. 529 530 COUNTER_FREQUENCY 531 Generic timer clock source frequency. 532 533 COUNTER_FREQUENCY_REAL 534 Generic timer clock source frequency if the real clock is 535 different from COUNTER_FREQUENCY, and can only be determined 536 at run time. 537 538- Tegra SoC options: 539 CONFIG_TEGRA_SUPPORT_NON_SECURE 540 541 Support executing U-Boot in non-secure (NS) mode. Certain 542 impossible actions will be skipped if the CPU is in NS mode, 543 such as ARM architectural timer initialization. 544 545- Linux Kernel Interface: 546 CONFIG_MEMSIZE_IN_BYTES [relevant for MIPS only] 547 548 When transferring memsize parameter to Linux, some versions 549 expect it to be in bytes, others in MB. 550 Define CONFIG_MEMSIZE_IN_BYTES to make it in bytes. 551 552 CONFIG_OF_LIBFDT 553 554 New kernel versions are expecting firmware settings to be 555 passed using flattened device trees (based on open firmware 556 concepts). 557 558 CONFIG_OF_LIBFDT 559 * New libfdt-based support 560 * Adds the "fdt" command 561 * The bootm command automatically updates the fdt 562 563 OF_TBCLK - The timebase frequency. 564 565 boards with QUICC Engines require OF_QE to set UCC MAC 566 addresses 567 568 CONFIG_OF_SYSTEM_SETUP 569 570 Other code has addition modification that it wants to make 571 to the flat device tree before handing it off to the kernel. 572 This causes ft_system_setup() to be called before booting 573 the kernel. 574 575 CONFIG_OF_IDE_FIXUP 576 577 U-Boot can detect if an IDE device is present or not. 578 If not, and this new config option is activated, U-Boot 579 removes the ATA node from the DTS before booting Linux, 580 so the Linux IDE driver does not probe the device and 581 crash. This is needed for buggy hardware (uc101) where 582 no pull down resistor is connected to the signal IDE5V_DD7. 583 584- vxWorks boot parameters: 585 586 bootvx constructs a valid bootline using the following 587 environments variables: bootdev, bootfile, ipaddr, netmask, 588 serverip, gatewayip, hostname, othbootargs. 589 It loads the vxWorks image pointed bootfile. 590 591 Note: If a "bootargs" environment is defined, it will override 592 the defaults discussed just above. 593 594- Cache Configuration for ARM: 595 CONFIG_SYS_L2_PL310 - Enable support for ARM PL310 L2 cache 596 controller 597 CONFIG_SYS_PL310_BASE - Physical base address of PL310 598 controller register space 599 600- Serial Ports: 601 CONFIG_PL011_CLOCK 602 603 If you have Amba PrimeCell PL011 UARTs, set this variable to 604 the clock speed of the UARTs. 605 606 CONFIG_PL01x_PORTS 607 608 If you have Amba PrimeCell PL010 or PL011 UARTs on your board, 609 define this to a list of base addresses for each (supported) 610 port. See e.g. include/configs/versatile.h 611 612 CONFIG_SERIAL_HW_FLOW_CONTROL 613 614 Define this variable to enable hw flow control in serial driver. 615 Current user of this option is drivers/serial/nsl16550.c driver 616 617- Serial Download Echo Mode: 618 CONFIG_LOADS_ECHO 619 If defined to 1, all characters received during a 620 serial download (using the "loads" command) are 621 echoed back. This might be needed by some terminal 622 emulations (like "cu"), but may as well just take 623 time on others. This setting #define's the initial 624 value of the "loads_echo" environment variable. 625 626- Removal of commands 627 If no commands are needed to boot, you can disable 628 CONFIG_CMDLINE to remove them. In this case, the command line 629 will not be available, and when U-Boot wants to execute the 630 boot command (on start-up) it will call board_run_command() 631 instead. This can reduce image size significantly for very 632 simple boot procedures. 633 634- Regular expression support: 635 CONFIG_REGEX 636 If this variable is defined, U-Boot is linked against 637 the SLRE (Super Light Regular Expression) library, 638 which adds regex support to some commands, as for 639 example "env grep" and "setexpr". 640 641- Watchdog: 642 CONFIG_SYS_WATCHDOG_FREQ 643 Some platforms automatically call WATCHDOG_RESET() 644 from the timer interrupt handler every 645 CONFIG_SYS_WATCHDOG_FREQ interrupts. If not set by the 646 board configuration file, a default of CONFIG_SYS_HZ/2 647 (i.e. 500) is used. Setting CONFIG_SYS_WATCHDOG_FREQ 648 to 0 disables calling WATCHDOG_RESET() from the timer 649 interrupt. 650 651- Real-Time Clock: 652 653 When CONFIG_CMD_DATE is selected, the type of the RTC 654 has to be selected, too. Define exactly one of the 655 following options: 656 657 CONFIG_RTC_PCF8563 - use Philips PCF8563 RTC 658 CONFIG_RTC_MC13XXX - use MC13783 or MC13892 RTC 659 CONFIG_RTC_MC146818 - use MC146818 RTC 660 CONFIG_RTC_DS1307 - use Maxim, Inc. DS1307 RTC 661 CONFIG_RTC_DS1337 - use Maxim, Inc. DS1337 RTC 662 CONFIG_RTC_DS1338 - use Maxim, Inc. DS1338 RTC 663 CONFIG_RTC_DS1339 - use Maxim, Inc. DS1339 RTC 664 CONFIG_RTC_DS164x - use Dallas DS164x RTC 665 CONFIG_RTC_ISL1208 - use Intersil ISL1208 RTC 666 CONFIG_RTC_MAX6900 - use Maxim, Inc. MAX6900 RTC 667 CONFIG_RTC_DS1337_NOOSC - Turn off the OSC output for DS1337 668 CONFIG_SYS_RV3029_TCR - enable trickle charger on 669 RV3029 RTC. 670 671 Note that if the RTC uses I2C, then the I2C interface 672 must also be configured. See I2C Support, below. 673 674- GPIO Support: 675 CONFIG_PCA953X - use NXP's PCA953X series I2C GPIO 676 677 The CONFIG_SYS_I2C_PCA953X_WIDTH option specifies a list of 678 chip-ngpio pairs that tell the PCA953X driver the number of 679 pins supported by a particular chip. 680 681 Note that if the GPIO device uses I2C, then the I2C interface 682 must also be configured. See I2C Support, below. 683 684- I/O tracing: 685 When CONFIG_IO_TRACE is selected, U-Boot intercepts all I/O 686 accesses and can checksum them or write a list of them out 687 to memory. See the 'iotrace' command for details. This is 688 useful for testing device drivers since it can confirm that 689 the driver behaves the same way before and after a code 690 change. Currently this is supported on sandbox and arm. To 691 add support for your architecture, add '#include <iotrace.h>' 692 to the bottom of arch/<arch>/include/asm/io.h and test. 693 694 Example output from the 'iotrace stats' command is below. 695 Note that if the trace buffer is exhausted, the checksum will 696 still continue to operate. 697 698 iotrace is enabled 699 Start: 10000000 (buffer start address) 700 Size: 00010000 (buffer size) 701 Offset: 00000120 (current buffer offset) 702 Output: 10000120 (start + offset) 703 Count: 00000018 (number of trace records) 704 CRC32: 9526fb66 (CRC32 of all trace records) 705 706- Timestamp Support: 707 708 When CONFIG_TIMESTAMP is selected, the timestamp 709 (date and time) of an image is printed by image 710 commands like bootm or iminfo. This option is 711 automatically enabled when you select CONFIG_CMD_DATE . 712 713- Partition Labels (disklabels) Supported: 714 Zero or more of the following: 715 CONFIG_MAC_PARTITION Apple's MacOS partition table. 716 CONFIG_ISO_PARTITION ISO partition table, used on CDROM etc. 717 CONFIG_EFI_PARTITION GPT partition table, common when EFI is the 718 bootloader. Note 2TB partition limit; see 719 disk/part_efi.c 720 CONFIG_SCSI) you must configure support for at 721 least one non-MTD partition type as well. 722 723- LBA48 Support 724 CONFIG_LBA48 725 726 Set this to enable support for disks larger than 137GB 727 Also look at CONFIG_SYS_64BIT_LBA. 728 Whithout these , LBA48 support uses 32bit variables and will 'only' 729 support disks up to 2.1TB. 730 731 CONFIG_SYS_64BIT_LBA: 732 When enabled, makes the IDE subsystem use 64bit sector addresses. 733 Default is 32bit. 734 735- NETWORK Support (PCI): 736 CONFIG_E1000_SPI 737 Utility code for direct access to the SPI bus on Intel 8257x. 738 This does not do anything useful unless you set at least one 739 of CONFIG_CMD_E1000 or CONFIG_E1000_SPI_GENERIC. 740 741 CONFIG_NATSEMI 742 Support for National dp83815 chips. 743 744 CONFIG_NS8382X 745 Support for National dp8382[01] gigabit chips. 746 747- NETWORK Support (other): 748 CONFIG_CALXEDA_XGMAC 749 Support for the Calxeda XGMAC device 750 751 CONFIG_LAN91C96 752 Support for SMSC's LAN91C96 chips. 753 754 CONFIG_LAN91C96_USE_32_BIT 755 Define this to enable 32 bit addressing 756 757 CONFIG_SMC91111 758 Support for SMSC's LAN91C111 chip 759 760 CONFIG_SMC91111_BASE 761 Define this to hold the physical address 762 of the device (I/O space) 763 764 CONFIG_SMC_USE_32_BIT 765 Define this if data bus is 32 bits 766 767 CONFIG_SMC_USE_IOFUNCS 768 Define this to use i/o functions instead of macros 769 (some hardware wont work with macros) 770 771 CONFIG_SYS_DAVINCI_EMAC_PHY_COUNT 772 Define this if you have more then 3 PHYs. 773 774 CONFIG_FTGMAC100 775 Support for Faraday's FTGMAC100 Gigabit SoC Ethernet 776 777 CONFIG_FTGMAC100_EGIGA 778 Define this to use GE link update with gigabit PHY. 779 Define this if FTGMAC100 is connected to gigabit PHY. 780 If your system has 10/100 PHY only, it might not occur 781 wrong behavior. Because PHY usually return timeout or 782 useless data when polling gigabit status and gigabit 783 control registers. This behavior won't affect the 784 correctnessof 10/100 link speed update. 785 786 CONFIG_SH_ETHER 787 Support for Renesas on-chip Ethernet controller 788 789 CONFIG_SH_ETHER_USE_PORT 790 Define the number of ports to be used 791 792 CONFIG_SH_ETHER_PHY_ADDR 793 Define the ETH PHY's address 794 795 CONFIG_SH_ETHER_CACHE_WRITEBACK 796 If this option is set, the driver enables cache flush. 797 798- TPM Support: 799 CONFIG_TPM 800 Support TPM devices. 801 802 CONFIG_TPM_TIS_INFINEON 803 Support for Infineon i2c bus TPM devices. Only one device 804 per system is supported at this time. 805 806 CONFIG_TPM_TIS_I2C_BURST_LIMITATION 807 Define the burst count bytes upper limit 808 809 CONFIG_TPM_ST33ZP24 810 Support for STMicroelectronics TPM devices. Requires DM_TPM support. 811 812 CONFIG_TPM_ST33ZP24_I2C 813 Support for STMicroelectronics ST33ZP24 I2C devices. 814 Requires TPM_ST33ZP24 and I2C. 815 816 CONFIG_TPM_ST33ZP24_SPI 817 Support for STMicroelectronics ST33ZP24 SPI devices. 818 Requires TPM_ST33ZP24 and SPI. 819 820 CONFIG_TPM_ATMEL_TWI 821 Support for Atmel TWI TPM device. Requires I2C support. 822 823 CONFIG_TPM_TIS_LPC 824 Support for generic parallel port TPM devices. Only one device 825 per system is supported at this time. 826 827 CONFIG_TPM_TIS_BASE_ADDRESS 828 Base address where the generic TPM device is mapped 829 to. Contemporary x86 systems usually map it at 830 0xfed40000. 831 832 CONFIG_TPM 833 Define this to enable the TPM support library which provides 834 functional interfaces to some TPM commands. 835 Requires support for a TPM device. 836 837 CONFIG_TPM_AUTH_SESSIONS 838 Define this to enable authorized functions in the TPM library. 839 Requires CONFIG_TPM and CONFIG_SHA1. 840 841- USB Support: 842 At the moment only the UHCI host controller is 843 supported (PIP405, MIP405); define 844 CONFIG_USB_UHCI to enable it. 845 define CONFIG_USB_KEYBOARD to enable the USB Keyboard 846 and define CONFIG_USB_STORAGE to enable the USB 847 storage devices. 848 Note: 849 Supported are USB Keyboards and USB Floppy drives 850 (TEAC FD-05PUB). 851 852 CONFIG_USB_EHCI_TXFIFO_THRESH enables setting of the 853 txfilltuning field in the EHCI controller on reset. 854 855 CONFIG_USB_DWC2_REG_ADDR the physical CPU address of the DWC2 856 HW module registers. 857 858- USB Device: 859 Define the below if you wish to use the USB console. 860 Once firmware is rebuilt from a serial console issue the 861 command "setenv stdin usbtty; setenv stdout usbtty" and 862 attach your USB cable. The Unix command "dmesg" should print 863 it has found a new device. The environment variable usbtty 864 can be set to gserial or cdc_acm to enable your device to 865 appear to a USB host as a Linux gserial device or a 866 Common Device Class Abstract Control Model serial device. 867 If you select usbtty = gserial you should be able to enumerate 868 a Linux host by 869 # modprobe usbserial vendor=0xVendorID product=0xProductID 870 else if using cdc_acm, simply setting the environment 871 variable usbtty to be cdc_acm should suffice. The following 872 might be defined in YourBoardName.h 873 874 CONFIG_USB_DEVICE 875 Define this to build a UDC device 876 877 CONFIG_USB_TTY 878 Define this to have a tty type of device available to 879 talk to the UDC device 880 881 CONFIG_USBD_HS 882 Define this to enable the high speed support for usb 883 device and usbtty. If this feature is enabled, a routine 884 int is_usbd_high_speed(void) 885 also needs to be defined by the driver to dynamically poll 886 whether the enumeration has succeded at high speed or full 887 speed. 888 889 If you have a USB-IF assigned VendorID then you may wish to 890 define your own vendor specific values either in BoardName.h 891 or directly in usbd_vendor_info.h. If you don't define 892 CONFIG_USBD_MANUFACTURER, CONFIG_USBD_PRODUCT_NAME, 893 CONFIG_USBD_VENDORID and CONFIG_USBD_PRODUCTID, then U-Boot 894 should pretend to be a Linux device to it's target host. 895 896 CONFIG_USBD_MANUFACTURER 897 Define this string as the name of your company for 898 - CONFIG_USBD_MANUFACTURER "my company" 899 900 CONFIG_USBD_PRODUCT_NAME 901 Define this string as the name of your product 902 - CONFIG_USBD_PRODUCT_NAME "acme usb device" 903 904 CONFIG_USBD_VENDORID 905 Define this as your assigned Vendor ID from the USB 906 Implementors Forum. This *must* be a genuine Vendor ID 907 to avoid polluting the USB namespace. 908 - CONFIG_USBD_VENDORID 0xFFFF 909 910 CONFIG_USBD_PRODUCTID 911 Define this as the unique Product ID 912 for your device 913 - CONFIG_USBD_PRODUCTID 0xFFFF 914 915- ULPI Layer Support: 916 The ULPI (UTMI Low Pin (count) Interface) PHYs are supported via 917 the generic ULPI layer. The generic layer accesses the ULPI PHY 918 via the platform viewport, so you need both the genric layer and 919 the viewport enabled. Currently only Chipidea/ARC based 920 viewport is supported. 921 To enable the ULPI layer support, define CONFIG_USB_ULPI and 922 CONFIG_USB_ULPI_VIEWPORT in your board configuration file. 923 If your ULPI phy needs a different reference clock than the 924 standard 24 MHz then you have to define CONFIG_ULPI_REF_CLK to 925 the appropriate value in Hz. 926 927- MMC Support: 928 The MMC controller on the Intel PXA is supported. To 929 enable this define CONFIG_MMC. The MMC can be 930 accessed from the boot prompt by mapping the device 931 to physical memory similar to flash. Command line is 932 enabled with CONFIG_CMD_MMC. The MMC driver also works with 933 the FAT fs. This is enabled with CONFIG_CMD_FAT. 934 935 CONFIG_SH_MMCIF 936 Support for Renesas on-chip MMCIF controller 937 938 CONFIG_SH_MMCIF_ADDR 939 Define the base address of MMCIF registers 940 941 CONFIG_SH_MMCIF_CLK 942 Define the clock frequency for MMCIF 943 944- USB Device Firmware Update (DFU) class support: 945 CONFIG_DFU_OVER_USB 946 This enables the USB portion of the DFU USB class 947 948 CONFIG_DFU_NAND 949 This enables support for exposing NAND devices via DFU. 950 951 CONFIG_DFU_RAM 952 This enables support for exposing RAM via DFU. 953 Note: DFU spec refer to non-volatile memory usage, but 954 allow usages beyond the scope of spec - here RAM usage, 955 one that would help mostly the developer. 956 957 CONFIG_SYS_DFU_DATA_BUF_SIZE 958 Dfu transfer uses a buffer before writing data to the 959 raw storage device. Make the size (in bytes) of this buffer 960 configurable. The size of this buffer is also configurable 961 through the "dfu_bufsiz" environment variable. 962 963 CONFIG_SYS_DFU_MAX_FILE_SIZE 964 When updating files rather than the raw storage device, 965 we use a static buffer to copy the file into and then write 966 the buffer once we've been given the whole file. Define 967 this to the maximum filesize (in bytes) for the buffer. 968 Default is 4 MiB if undefined. 969 970 DFU_DEFAULT_POLL_TIMEOUT 971 Poll timeout [ms], is the timeout a device can send to the 972 host. The host must wait for this timeout before sending 973 a subsequent DFU_GET_STATUS request to the device. 974 975 DFU_MANIFEST_POLL_TIMEOUT 976 Poll timeout [ms], which the device sends to the host when 977 entering dfuMANIFEST state. Host waits this timeout, before 978 sending again an USB request to the device. 979 980- Journaling Flash filesystem support: 981 CONFIG_SYS_JFFS2_FIRST_SECTOR, 982 CONFIG_SYS_JFFS2_FIRST_BANK, CONFIG_SYS_JFFS2_NUM_BANKS 983 Define these for a default partition on a NOR device 984 985- Keyboard Support: 986 See Kconfig help for available keyboard drivers. 987 988- Video support: 989 CONFIG_FSL_DIU_FB 990 Enable the Freescale DIU video driver. Reference boards for 991 SOCs that have a DIU should define this macro to enable DIU 992 support, and should also define these other macros: 993 994 CONFIG_SYS_DIU_ADDR 995 CONFIG_VIDEO 996 CONFIG_CFB_CONSOLE 997 CONFIG_VIDEO_SW_CURSOR 998 CONFIG_VGA_AS_SINGLE_DEVICE 999 CONFIG_VIDEO_BMP_LOGO 1000
1001 The DIU driver will look for the 'video-mode' environment 1002 variable, and if defined, enable the DIU as a console during 1003 boot. See the documentation file doc/README.video for a 1004 description of this variable. 1005 1006- LCD Support: CONFIG_LCD 1007 1008 Define this to enable LCD support (for output to LCD 1009 display); also select one of the supported displays 1010 by defining one of these: 1011 1012 CONFIG_ATMEL_LCD: 1013 1014 HITACHI TX09D70VM1CCA, 3.5", 240x320. 1015 1016 CONFIG_NEC_NL6448AC33: 1017 1018 NEC NL6448AC33-18. Active, color, single scan. 1019 1020 CONFIG_NEC_NL6448BC20 1021 1022 NEC NL6448BC20-08. 6.5", 640x480. 1023 Active, color, single scan. 1024 1025 CONFIG_NEC_NL6448BC33_54 1026 1027 NEC NL6448BC33-54. 10.4", 640x480. 1028 Active, color, single scan. 1029 1030 CONFIG_SHARP_16x9 1031 1032 Sharp 320x240. Active, color, single scan. 1033 It isn't 16x9, and I am not sure what it is. 1034 1035 CONFIG_SHARP_LQ64D341 1036 1037 Sharp LQ64D341 display, 640x480. 1038 Active, color, single scan. 1039 1040 CONFIG_HLD1045 1041 1042 HLD1045 display, 640x480. 1043 Active, color, single scan. 1044 1045 CONFIG_OPTREX_BW 1046 1047 Optrex CBL50840-2 NF-FW 99 22 M5 1048 or 1049 Hitachi LMG6912RPFC-00T 1050 or 1051 Hitachi SP14Q002 1052 1053 320x240. Black & white. 1054 1055 CONFIG_LCD_ALIGNMENT 1056 1057 Normally the LCD is page-aligned (typically 4KB). If this is 1058 defined then the LCD will be aligned to this value instead. 1059 For ARM it is sometimes useful to use MMU_SECTION_SIZE 1060 here, since it is cheaper to change data cache settings on 1061 a per-section basis. 1062 1063 1064 CONFIG_LCD_ROTATION 1065 1066 Sometimes, for example if the display is mounted in portrait 1067 mode or even if it's mounted landscape but rotated by 180degree, 1068 we need to rotate our content of the display relative to the 1069 framebuffer, so that user can read the messages which are 1070 printed out. 1071 Once CONFIG_LCD_ROTATION is defined, the lcd_console will be 1072 initialized with a given rotation from "vl_rot" out of 1073 "vidinfo_t" which is provided by the board specific code. 1074 The value for vl_rot is coded as following (matching to 1075 fbcon=rotate:<n> linux-kernel commandline): 1076 0 = no rotation respectively 0 degree 1077 1 = 90 degree rotation 1078 2 = 180 degree rotation 1079 3 = 270 degree rotation 1080 1081 If CONFIG_LCD_ROTATION is not defined, the console will be 1082 initialized with 0degree rotation. 1083 1084 CONFIG_LCD_BMP_RLE8 1085 1086 Support drawing of RLE8-compressed bitmaps on the LCD. 1087 1088- MII/PHY support: 1089 CONFIG_PHY_CLOCK_FREQ (ppc4xx) 1090 1091 The clock frequency of the MII bus 1092 1093 CONFIG_PHY_RESET_DELAY 1094 1095 Some PHY like Intel LXT971A need extra delay after 1096 reset before any MII register access is possible. 1097 For such PHY, set this option to the usec delay 1098 required. (minimum 300usec for LXT971A) 1099 1100 CONFIG_PHY_CMD_DELAY (ppc4xx) 1101 1102 Some PHY like Intel LXT971A need extra delay after 1103 command issued before MII status register can be read 1104 1105- IP address: 1106 CONFIG_IPADDR 1107 1108 Define a default value for the IP address to use for 1109 the default Ethernet interface, in case this is not 1110 determined through e.g. bootp. 1111 (Environment variable "ipaddr") 1112 1113- Server IP address: 1114 CONFIG_SERVERIP 1115 1116 Defines a default value for the IP address of a TFTP 1117 server to contact when using the "tftboot" command. 1118 (Environment variable "serverip") 1119 1120- Gateway IP address: 1121 CONFIG_GATEWAYIP 1122 1123 Defines a default value for the IP address of the 1124 default router where packets to other networks are 1125 sent to. 1126 (Environment variable "gatewayip") 1127 1128- Subnet mask: 1129 CONFIG_NETMASK 1130 1131 Defines a default value for the subnet mask (or 1132 routing prefix) which is used to determine if an IP 1133 address belongs to the local subnet or needs to be 1134 forwarded through a router. 1135 (Environment variable "netmask") 1136 1137- BOOTP Recovery Mode: 1138 CONFIG_BOOTP_RANDOM_DELAY 1139 1140 If you have many targets in a network that try to 1141 boot using BOOTP, you may want to avoid that all 1142 systems send out BOOTP requests at precisely the same 1143 moment (which would happen for instance at recovery 1144 from a power failure, when all systems will try to 1145 boot, thus flooding the BOOTP server. Defining 1146 CONFIG_BOOTP_RANDOM_DELAY causes a random delay to be 1147 inserted before sending out BOOTP requests. The 1148 following delays are inserted then: 1149 1150 1st BOOTP request: delay 0 ... 1 sec 1151 2nd BOOTP request: delay 0 ... 2 sec 1152 3rd BOOTP request: delay 0 ... 4 sec 1153 4th and following 1154 BOOTP requests: delay 0 ... 8 sec 1155 1156 CONFIG_BOOTP_ID_CACHE_SIZE 1157 1158 BOOTP packets are uniquely identified using a 32-bit ID. The 1159 server will copy the ID from client requests to responses and 1160 U-Boot will use this to determine if it is the destination of 1161 an incoming response. Some servers will check that addresses 1162 aren't in use before handing them out (usually using an ARP 1163 ping) and therefore take up to a few hundred milliseconds to 1164 respond. Network congestion may also influence the time it 1165 takes for a response to make it back to the client. If that 1166 time is too long, U-Boot will retransmit requests. In order 1167 to allow earlier responses to still be accepted after these 1168 retransmissions, U-Boot's BOOTP client keeps a small cache of 1169 IDs. The CONFIG_BOOTP_ID_CACHE_SIZE controls the size of this 1170 cache. The default is to keep IDs for up to four outstanding 1171 requests. Increasing this will allow U-Boot to accept offers 1172 from a BOOTP client in networks with unusually high latency. 1173 1174- DHCP Advanced Options: 1175 You can fine tune the DHCP functionality by defining 1176 CONFIG_BOOTP_* symbols: 1177 1178 CONFIG_BOOTP_NISDOMAIN 1179 CONFIG_BOOTP_BOOTFILESIZE 1180 CONFIG_BOOTP_NTPSERVER 1181 CONFIG_BOOTP_TIMEOFFSET 1182 CONFIG_BOOTP_VENDOREX 1183 CONFIG_BOOTP_MAY_FAIL 1184 1185 CONFIG_BOOTP_MAY_FAIL - If the DHCP server is not found 1186 after the configured retry count, the call will fail 1187 instead of starting over. This can be used to fail over 1188 to Link-local IP address configuration if the DHCP server 1189 is not available. 1190 1191 CONFIG_BOOTP_DHCP_REQUEST_DELAY 1192 1193 A 32bit value in microseconds for a delay between 1194 receiving a "DHCP Offer" and sending the "DHCP Request". 1195 This fixes a problem with certain DHCP servers that don't 1196 respond 100% of the time to a "DHCP request". E.g. On an 1197 AT91RM9200 processor running at 180MHz, this delay needed 1198 to be *at least* 15,000 usec before a Windows Server 2003 1199 DHCP server would reply 100% of the time. I recommend at 1200 least 50,000 usec to be safe. The alternative is to hope 1201 that one of the retries will be successful but note that 1202 the DHCP timeout and retry process takes a longer than 1203 this delay. 1204 1205 - Link-local IP address negotiation: 1206 Negotiate with other link-local clients on the local network 1207 for an address that doesn't require explicit configuration. 1208 This is especially useful if a DHCP server cannot be guaranteed 1209 to exist in all environments that the device must operate. 1210 1211 See doc/README.link-local for more information. 1212 1213 - MAC address from environment variables 1214 1215 FDT_SEQ_MACADDR_FROM_ENV 1216 1217 Fix-up device tree with MAC addresses fetched sequentially from 1218 environment variables. This config work on assumption that 1219 non-usable ethernet node of device-tree are either not present 1220 or their status has been marked as "disabled". 1221 1222 - CDP Options: 1223 CONFIG_CDP_DEVICE_ID 1224 1225 The device id used in CDP trigger frames. 1226 1227 CONFIG_CDP_DEVICE_ID_PREFIX 1228 1229 A two character string which is prefixed to the MAC address 1230 of the device. 1231 1232 CONFIG_CDP_PORT_ID 1233 1234 A printf format string which contains the ascii name of 1235 the port. Normally is set to "eth%d" which sets 1236 eth0 for the first Ethernet, eth1 for the second etc. 1237 1238 CONFIG_CDP_CAPABILITIES 1239 1240 A 32bit integer which indicates the device capabilities; 1241 0x00000010 for a normal host which does not forwards. 1242 1243 CONFIG_CDP_VERSION 1244 1245 An ascii string containing the version of the software. 1246 1247 CONFIG_CDP_PLATFORM 1248 1249 An ascii string containing the name of the platform. 1250 1251 CONFIG_CDP_TRIGGER 1252 1253 A 32bit integer sent on the trigger. 1254 1255 CONFIG_CDP_POWER_CONSUMPTION 1256 1257 A 16bit integer containing the power consumption of the 1258 device in .1 of milliwatts. 1259 1260 CONFIG_CDP_APPLIANCE_VLAN_TYPE 1261 1262 A byte containing the id of the VLAN. 1263 1264- Status LED: CONFIG_LED_STATUS 1265 1266 Several configurations allow to display the current 1267 status using a LED. For instance, the LED will blink 1268 fast while running U-Boot code, stop blinking as 1269 soon as a reply to a BOOTP request was received, and 1270 start blinking slow once the Linux kernel is running 1271 (supported by a status LED driver in the Linux 1272 kernel). Defining CONFIG_LED_STATUS enables this 1273 feature in U-Boot. 1274 1275 Additional options: 1276 1277 CONFIG_LED_STATUS_GPIO 1278 The status LED can be connected to a GPIO pin. 1279 In such cases, the gpio_led driver can be used as a 1280 status LED backend implementation. Define CONFIG_LED_STATUS_GPIO 1281 to include the gpio_led driver in the U-Boot binary. 1282 1283 CONFIG_GPIO_LED_INVERTED_TABLE 1284 Some GPIO connected LEDs may have inverted polarity in which 1285 case the GPIO high value corresponds to LED off state and 1286 GPIO low value corresponds to LED on state. 1287 In such cases CONFIG_GPIO_LED_INVERTED_TABLE may be defined 1288 with a list of GPIO LEDs that have inverted polarity. 1289 1290- I2C Support: 1291 CONFIG_SYS_NUM_I2C_BUSES 1292 Hold the number of i2c buses you want to use. 1293 1294 CONFIG_SYS_I2C_DIRECT_BUS 1295 define this, if you don't use i2c muxes on your hardware. 1296 if CONFIG_SYS_I2C_MAX_HOPS is not defined or == 0 you can 1297 omit this define. 1298 1299 CONFIG_SYS_I2C_MAX_HOPS 1300 define how many muxes are maximal consecutively connected 1301 on one i2c bus. If you not use i2c muxes, omit this 1302 define. 1303 1304 CONFIG_SYS_I2C_BUSES 1305 hold a list of buses you want to use, only used if 1306 CONFIG_SYS_I2C_DIRECT_BUS is not defined, for example 1307 a board with CONFIG_SYS_I2C_MAX_HOPS = 1 and 1308 CONFIG_SYS_NUM_I2C_BUSES = 9: 1309 1310 CONFIG_SYS_I2C_BUSES {{0, {I2C_NULL_HOP}}, \ 1311 {0, {{I2C_MUX_PCA9547, 0x70, 1}}}, \ 1312 {0, {{I2C_MUX_PCA9547, 0x70, 2}}}, \ 1313 {0, {{I2C_MUX_PCA9547, 0x70, 3}}}, \ 1314 {0, {{I2C_MUX_PCA9547, 0x70, 4}}}, \ 1315 {0, {{I2C_MUX_PCA9547, 0x70, 5}}}, \ 1316 {1, {I2C_NULL_HOP}}, \ 1317 {1, {{I2C_MUX_PCA9544, 0x72, 1}}}, \ 1318 {1, {{I2C_MUX_PCA9544, 0x72, 2}}}, \ 1319 } 1320 1321 which defines 1322 bus 0 on adapter 0 without a mux 1323 bus 1 on adapter 0 with a PCA9547 on address 0x70 port 1 1324 bus 2 on adapter 0 with a PCA9547 on address 0x70 port 2 1325 bus 3 on adapter 0 with a PCA9547 on address 0x70 port 3 1326 bus 4 on adapter 0 with a PCA9547 on address 0x70 port 4 1327 bus 5 on adapter 0 with a PCA9547 on address 0x70 port 5 1328 bus 6 on adapter 1 without a mux 1329 bus 7 on adapter 1 with a PCA9544 on address 0x72 port 1 1330 bus 8 on adapter 1 with a PCA9544 on address 0x72 port 2 1331 1332 If you do not have i2c muxes on your board, omit this define. 1333 1334- Legacy I2C Support: 1335 If you use the software i2c interface (CONFIG_SYS_I2C_SOFT) 1336 then the following macros need to be defined (examples are 1337 from include/configs/lwmon.h): 1338 1339 I2C_INIT 1340 1341 (Optional). Any commands necessary to enable the I2C 1342 controller or configure ports. 1343 1344 eg: #define I2C_INIT (immr->im_cpm.cp_pbdir |= PB_SCL) 1345 1346 I2C_ACTIVE 1347 1348 The code necessary to make the I2C data line active 1349 (driven). If the data line is open collector, this 1350 define can be null. 1351 1352 eg: #define I2C_ACTIVE (immr->im_cpm.cp_pbdir |= PB_SDA) 1353 1354 I2C_TRISTATE 1355 1356 The code necessary to make the I2C data line tri-stated 1357 (inactive). If the data line is open collector, this 1358 define can be null. 1359 1360 eg: #define I2C_TRISTATE (immr->im_cpm.cp_pbdir &= ~PB_SDA) 1361 1362 I2C_READ 1363 1364 Code that returns true if the I2C data line is high, 1365 false if it is low. 1366 1367 eg: #define I2C_READ ((immr->im_cpm.cp_pbdat & PB_SDA) != 0) 1368 1369 I2C_SDA(bit) 1370 1371 If <bit> is true, sets the I2C data line high. If it 1372 is false, it clears it (low). 1373 1374 eg: #define I2C_SDA(bit) \ 1375 if(bit) immr->im_cpm.cp_pbdat |= PB_SDA; \ 1376 else immr->im_cpm.cp_pbdat &= ~PB_SDA 1377 1378 I2C_SCL(bit) 1379 1380 If <bit> is true, sets the I2C clock line high. If it 1381 is false, it clears it (low). 1382 1383 eg: #define I2C_SCL(bit) \ 1384 if(bit) immr->im_cpm.cp_pbdat |= PB_SCL; \ 1385 else immr->im_cpm.cp_pbdat &= ~PB_SCL 1386 1387 I2C_DELAY 1388 1389 This delay is invoked four times per clock cycle so this 1390 controls the rate of data transfer. The data rate thus 1391 is 1 / (I2C_DELAY * 4). Often defined to be something 1392 like: 1393 1394 #define I2C_DELAY udelay(2) 1395 1396 CONFIG_SOFT_I2C_GPIO_SCL / CONFIG_SOFT_I2C_GPIO_SDA 1397 1398 If your arch supports the generic GPIO framework (asm/gpio.h), 1399 then you may alternatively define the two GPIOs that are to be 1400 used as SCL / SDA. Any of the previous I2C_xxx macros will 1401 have GPIO-based defaults assigned to them as appropriate. 1402 1403 You should define these to the GPIO value as given directly to 1404 the generic GPIO functions. 1405 1406 CONFIG_SYS_I2C_INIT_BOARD 1407 1408 When a board is reset during an i2c bus transfer 1409 chips might think that the current transfer is still 1410 in progress. On some boards it is possible to access 1411 the i2c SCLK line directly, either by using the 1412 processor pin as a GPIO or by having a second pin 1413 connected to the bus. If this option is defined a 1414 custom i2c_init_board() routine in boards/xxx/board.c 1415 is run early in the boot sequence. 1416 1417 CONFIG_I2C_MULTI_BUS 1418 1419 This option allows the use of multiple I2C buses, each of which 1420 must have a controller. At any point in time, only one bus is 1421 active. To switch to a different bus, use the 'i2c dev' command. 1422 Note that bus numbering is zero-based. 1423 1424 CONFIG_SYS_I2C_NOPROBES 1425 1426 This option specifies a list of I2C devices that will be skipped 1427 when the 'i2c probe' command is issued. If CONFIG_I2C_MULTI_BUS 1428 is set, specify a list of bus-device pairs. Otherwise, specify 1429 a 1D array of device addresses 1430 1431 e.g. 1432 #undef CONFIG_I2C_MULTI_BUS 1433 #define CONFIG_SYS_I2C_NOPROBES {0x50,0x68} 1434 1435 will skip addresses 0x50 and 0x68 on a board with one I2C bus 1436 1437 #define CONFIG_I2C_MULTI_BUS 1438 #define CONFIG_SYS_I2C_NOPROBES {{0,0x50},{0,0x68},{1,0x54}} 1439 1440 will skip addresses 0x50 and 0x68 on bus 0 and address 0x54 on bus 1 1441 1442 CONFIG_SYS_SPD_BUS_NUM 1443 1444 If defined, then this indicates the I2C bus number for DDR SPD. 1445 If not defined, then U-Boot assumes that SPD is on I2C bus 0. 1446 1447 CONFIG_SYS_RTC_BUS_NUM 1448 1449 If defined, then this indicates the I2C bus number for the RTC. 1450 If not defined, then U-Boot assumes that RTC is on I2C bus 0. 1451 1452 CONFIG_SOFT_I2C_READ_REPEATED_START 1453 1454 defining this will force the i2c_read() function in 1455 the soft_i2c driver to perform an I2C repeated start 1456 between writing the address pointer and reading the 1457 data. If this define is omitted the default behaviour 1458 of doing a stop-start sequence will be used. Most I2C 1459 devices can use either method, but some require one or 1460 the other. 1461 1462- SPI Support: CONFIG_SPI 1463 1464 Enables SPI driver (so far only tested with 1465 SPI EEPROM, also an instance works with Crystal A/D and 1466 D/As on the SACSng board) 1467 1468 CONFIG_SYS_SPI_MXC_WAIT 1469 Timeout for waiting until spi transfer completed. 1470 default: (CONFIG_SYS_HZ/100) /* 10 ms */ 1471 1472- FPGA Support: CONFIG_FPGA 1473 1474 Enables FPGA subsystem. 1475 1476 CONFIG_FPGA_<vendor> 1477 1478 Enables support for specific chip vendors. 1479 (ALTERA, XILINX) 1480 1481 CONFIG_FPGA_<family> 1482 1483 Enables support for FPGA family. 1484 (SPARTAN2, SPARTAN3, VIRTEX2, CYCLONE2, ACEX1K, ACEX) 1485 1486 CONFIG_FPGA_COUNT 1487 1488 Specify the number of FPGA devices to support. 1489 1490 CONFIG_SYS_FPGA_PROG_FEEDBACK 1491 1492 Enable printing of hash marks during FPGA configuration. 1493 1494 CONFIG_SYS_FPGA_CHECK_BUSY 1495 1496 Enable checks on FPGA configuration interface busy 1497 status by the configuration function. This option 1498 will require a board or device specific function to 1499 be written. 1500 1501 CONFIG_FPGA_DELAY 1502 1503 If defined, a function that provides delays in the FPGA 1504 configuration driver. 1505 1506 CONFIG_SYS_FPGA_CHECK_CTRLC 1507 Allow Control-C to interrupt FPGA configuration 1508 1509 CONFIG_SYS_FPGA_CHECK_ERROR 1510 1511 Check for configuration errors during FPGA bitfile 1512 loading. For example, abort during Virtex II 1513 configuration if the INIT_B line goes low (which 1514 indicated a CRC error). 1515 1516 CONFIG_SYS_FPGA_WAIT_INIT 1517 1518 Maximum time to wait for the INIT_B line to de-assert 1519 after PROB_B has been de-asserted during a Virtex II 1520 FPGA configuration sequence. The default time is 500 1521 ms. 1522 1523 CONFIG_SYS_FPGA_WAIT_BUSY 1524 1525 Maximum time to wait for BUSY to de-assert during 1526 Virtex II FPGA configuration. The default is 5 ms. 1527 1528 CONFIG_SYS_FPGA_WAIT_CONFIG 1529 1530 Time to wait after FPGA configuration. The default is 1531 200 ms. 1532 1533- Vendor Parameter Protection: 1534 1535 U-Boot considers the values of the environment 1536 variables "serial#" (Board Serial Number) and 1537 "ethaddr" (Ethernet Address) to be parameters that 1538 are set once by the board vendor / manufacturer, and 1539 protects these variables from casual modification by 1540 the user. Once set, these variables are read-only, 1541 and write or delete attempts are rejected. You can 1542 change this behaviour: 1543 1544 If CONFIG_ENV_OVERWRITE is #defined in your config 1545 file, the write protection for vendor parameters is 1546 completely disabled. Anybody can change or delete 1547 these parameters. 1548 1549 Alternatively, if you define _both_ an ethaddr in the 1550 default env _and_ CONFIG_OVERWRITE_ETHADDR_ONCE, a default 1551 Ethernet address is installed in the environment, 1552 which can be changed exactly ONCE by the user. [The 1553 serial# is unaffected by this, i. e. it remains 1554 read-only.] 1555 1556 The same can be accomplished in a more flexible way 1557 for any variable by configuring the type of access 1558 to allow for those variables in the ".flags" variable 1559 or define CONFIG_ENV_FLAGS_LIST_STATIC. 1560 1561- Protected RAM: 1562 CONFIG_PRAM 1563 1564 Define this variable to enable the reservation of 1565 "protected RAM", i. e. RAM which is not overwritten 1566 by U-Boot. Define CONFIG_PRAM to hold the number of 1567 kB you want to reserve for pRAM. You can overwrite 1568 this default value by defining an environment 1569 variable "pram" to the number of kB you want to 1570 reserve. Note that the board info structure will 1571 still show the full amount of RAM. If pRAM is 1572 reserved, a new environment variable "mem" will 1573 automatically be defined to hold the amount of 1574 remaining RAM in a form that can be passed as boot 1575 argument to Linux, for instance like that: 1576 1577 setenv bootargs ... mem=\${mem} 1578 saveenv 1579 1580 This way you can tell Linux not to use this memory, 1581 either, which results in a memory region that will 1582 not be affected by reboots. 1583 1584 *WARNING* If your board configuration uses automatic 1585 detection of the RAM size, you must make sure that 1586 this memory test is non-destructive. So far, the 1587 following board configurations are known to be 1588 "pRAM-clean": 1589 1590 IVMS8, IVML24, SPD8xx, 1591 HERMES, IP860, RPXlite, LWMON, 1592 FLAGADM 1593 1594- Error Recovery: 1595 CONFIG_NET_RETRY_COUNT 1596 1597 This variable defines the number of retries for 1598 network operations like ARP, RARP, TFTP, or BOOTP 1599 before giving up the operation. If not defined, a 1600 default value of 5 is used. 1601 1602 CONFIG_ARP_TIMEOUT 1603 1604 Timeout waiting for an ARP reply in milliseconds. 1605 1606 CONFIG_NFS_TIMEOUT 1607 1608 Timeout in milliseconds used in NFS protocol. 1609 If you encounter "ERROR: Cannot umount" in nfs command, 1610 try longer timeout such as 1611 #define CONFIG_NFS_TIMEOUT 10000UL 1612 1613 Note: 1614 1615 In the current implementation, the local variables 1616 space and global environment variables space are 1617 separated. Local variables are those you define by 1618 simply typing `name=value'. To access a local 1619 variable later on, you have write `$name' or 1620 `${name}'; to execute the contents of a variable 1621 directly type `$name' at the command prompt. 1622 1623 Global environment variables are those you use 1624 setenv/printenv to work with. To run a command stored 1625 in such a variable, you need to use the run command, 1626 and you must not use the '$' sign to access them. 1627 1628 To store commands and special characters in a 1629 variable, please use double quotation marks 1630 surrounding the whole text of the variable, instead 1631 of the backslashes before semicolons and special 1632 symbols. 1633 1634- Command Line Editing and History: 1635 CONFIG_CMDLINE_PS_SUPPORT 1636 1637 Enable support for changing the command prompt string 1638 at run-time. Only static string is supported so far. 1639 The string is obtained from environment variables PS1 1640 and PS2. 1641 1642- Default Environment: 1643 CONFIG_EXTRA_ENV_SETTINGS 1644 1645 Define this to contain any number of null terminated 1646 strings (variable = value pairs) that will be part of 1647 the default environment compiled into the boot image. 1648 1649 For example, place something like this in your 1650 board's config file: 1651 1652 #define CONFIG_EXTRA_ENV_SETTINGS \ 1653 "myvar1=value1\0" \ 1654 "myvar2=value2\0" 1655 1656 Warning: This method is based on knowledge about the 1657 internal format how the environment is stored by the 1658 U-Boot code. This is NOT an official, exported 1659 interface! Although it is unlikely that this format 1660 will change soon, there is no guarantee either. 1661 You better know what you are doing here. 1662 1663 Note: overly (ab)use of the default environment is 1664 discouraged. Make sure to check other ways to preset 1665 the environment like the "source" command or the 1666 boot command first. 1667 1668 CONFIG_DELAY_ENVIRONMENT 1669 1670 Normally the environment is loaded when the board is 1671 initialised so that it is available to U-Boot. This inhibits 1672 that so that the environment is not available until 1673 explicitly loaded later by U-Boot code. With CONFIG_OF_CONTROL 1674 this is instead controlled by the value of 1675 /config/load-environment. 1676 1677- TFTP Fixed UDP Port: 1678 CONFIG_TFTP_PORT 1679 1680 If this is defined, the environment variable tftpsrcp 1681 is used to supply the TFTP UDP source port value. 1682 If tftpsrcp isn't defined, the normal pseudo-random port 1683 number generator is used. 1684 1685 Also, the environment variable tftpdstp is used to supply 1686 the TFTP UDP destination port value. If tftpdstp isn't 1687 defined, the normal port 69 is used. 1688 1689 The purpose for tftpsrcp is to allow a TFTP server to 1690 blindly start the TFTP transfer using the pre-configured 1691 target IP address and UDP port. This has the effect of 1692 "punching through" the (Windows XP) firewall, allowing 1693 the remainder of the TFTP transfer to proceed normally. 1694 A better solution is to properly configure the firewall, 1695 but sometimes that is not allowed. 1696 1697 CONFIG_STANDALONE_LOAD_ADDR 1698 1699 This option defines a board specific value for the 1700 address where standalone program gets loaded, thus 1701 overwriting the architecture dependent default 1702 settings. 1703 1704- Frame Buffer Address: 1705 CONFIG_FB_ADDR 1706 1707 Define CONFIG_FB_ADDR if you want to use specific 1708 address for frame buffer. This is typically the case 1709 when using a graphics controller has separate video 1710 memory. U-Boot will then place the frame buffer at 1711 the given address instead of dynamically reserving it 1712 in system RAM by calling lcd_setmem(), which grabs 1713 the memory for the frame buffer depending on the 1714 configured panel size. 1715 1716 Please see board_init_f function. 1717 1718- Automatic software updates via TFTP server 1719 CONFIG_UPDATE_TFTP 1720 CONFIG_UPDATE_TFTP_CNT_MAX 1721 CONFIG_UPDATE_TFTP_MSEC_MAX 1722 1723 These options enable and control the auto-update feature; 1724 for a more detailed description refer to doc/README.update. 1725 1726- MTD Support (mtdparts command, UBI support) 1727 CONFIG_MTD_UBI_WL_THRESHOLD 1728 This parameter defines the maximum difference between the highest 1729 erase counter value and the lowest erase counter value of eraseblocks 1730 of UBI devices. When this threshold is exceeded, UBI starts performing 1731 wear leveling by means of moving data from eraseblock with low erase 1732 counter to eraseblocks with high erase counter. 1733 1734 The default value should be OK for SLC NAND flashes, NOR flashes and 1735 other flashes which have eraseblock life-cycle 100000 or more. 1736 However, in case of MLC NAND flashes which typically have eraseblock 1737 life-cycle less than 10000, the threshold should be lessened (e.g., 1738 to 128 or 256, although it does not have to be power of 2). 1739 1740 default: 4096 1741 1742 CONFIG_MTD_UBI_BEB_LIMIT 1743 This option specifies the maximum bad physical eraseblocks UBI 1744 expects on the MTD device (per 1024 eraseblocks). If the 1745 underlying flash does not admit of bad eraseblocks (e.g. NOR 1746 flash), this value is ignored. 1747 1748 NAND datasheets often specify the minimum and maximum NVM 1749 (Number of Valid Blocks) for the flashes' endurance lifetime. 1750 The maximum expected bad eraseblocks per 1024 eraseblocks 1751 then can be calculated as "1024 * (1 - MinNVB / MaxNVB)", 1752 which gives 20 for most NANDs (MaxNVB is basically the total 1753 count of eraseblocks on the chip). 1754 1755 To put it differently, if this value is 20, UBI will try to 1756 reserve about 1.9% of physical eraseblocks for bad blocks 1757 handling. And that will be 1.9% of eraseblocks on the entire 1758 NAND chip, not just the MTD partition UBI attaches. This means 1759 that if you have, say, a NAND flash chip admits maximum 40 bad 1760 eraseblocks, and it is split on two MTD partitions of the same 1761 size, UBI will reserve 40 eraseblocks when attaching a 1762 partition. 1763 1764 default: 20 1765 1766 CONFIG_MTD_UBI_FASTMAP 1767 Fastmap is a mechanism which allows attaching an UBI device 1768 in nearly constant time. Instead of scanning the whole MTD device it 1769 only has to locate a checkpoint (called fastmap) on the device. 1770 The on-flash fastmap contains all information needed to attach 1771 the device. Using fastmap makes only sense on large devices where 1772 attaching by scanning takes long. UBI will not automatically install 1773 a fastmap on old images, but you can set the UBI parameter 1774 CONFIG_MTD_UBI_FASTMAP_AUTOCONVERT to 1 if you want so. Please note 1775 that fastmap-enabled images are still usable with UBI implementations 1776 without fastmap support. On typical flash devices the whole fastmap 1777 fits into one PEB. UBI will reserve PEBs to hold two fastmaps. 1778 1779 CONFIG_MTD_UBI_FASTMAP_AUTOCONVERT 1780 Set this parameter to enable fastmap automatically on images 1781 without a fastmap. 1782 default: 0 1783 1784 CONFIG_MTD_UBI_FM_DEBUG 1785 Enable UBI fastmap debug 1786 default: 0 1787 1788- SPL framework 1789 CONFIG_SPL 1790 Enable building of SPL globally. 1791 1792 CONFIG_SPL_MAX_FOOTPRINT 1793 Maximum size in memory allocated to the SPL, BSS included. 1794 When defined, the linker checks that the actual memory 1795 used by SPL from _start to __bss_end does not exceed it. 1796 CONFIG_SPL_MAX_FOOTPRINT and CONFIG_SPL_BSS_MAX_SIZE 1797 must not be both defined at the same time. 1798 1799 CONFIG_SPL_MAX_SIZE 1800 Maximum size of the SPL image (text, data, rodata, and 1801 linker lists sections), BSS excluded. 1802 When defined, the linker checks that the actual size does 1803 not exceed it. 1804 1805 CONFIG_SPL_RELOC_TEXT_BASE 1806 Address to relocate to. If unspecified, this is equal to 1807 CONFIG_SPL_TEXT_BASE (i.e. no relocation is done). 1808 1809 CONFIG_SPL_BSS_START_ADDR 1810 Link address for the BSS within the SPL binary. 1811 1812 CONFIG_SPL_BSS_MAX_SIZE 1813 Maximum size in memory allocated to the SPL BSS. 1814 When defined, the linker checks that the actual memory used 1815 by SPL from __bss_start to __bss_end does not exceed it. 1816 CONFIG_SPL_MAX_FOOTPRINT and CONFIG_SPL_BSS_MAX_SIZE 1817 must not be both defined at the same time. 1818 1819 CONFIG_SPL_STACK 1820 Adress of the start of the stack SPL will use 1821 1822 CONFIG_SPL_PANIC_ON_RAW_IMAGE 1823 When defined, SPL will panic() if the image it has 1824 loaded does not have a signature. 1825 Defining this is useful when code which loads images 1826 in SPL cannot guarantee that absolutely all read errors 1827 will be caught. 1828 An example is the LPC32XX MLC NAND driver, which will 1829 consider that a completely unreadable NAND block is bad, 1830 and thus should be skipped silently. 1831 1832 CONFIG_SPL_RELOC_STACK 1833 Adress of the start of the stack SPL will use after 1834 relocation. If unspecified, this is equal to 1835 CONFIG_SPL_STACK. 1836 1837 CONFIG_SYS_SPL_MALLOC_START 1838 Starting address of the malloc pool used in SPL. 1839 When this option is set the full malloc is used in SPL and 1840 it is set up by spl_init() and before that, the simple malloc() 1841 can be used if CONFIG_SYS_MALLOC_F is defined. 1842 1843 CONFIG_SYS_SPL_MALLOC_SIZE 1844 The size of the malloc pool used in SPL. 1845 1846 CONFIG_SPL_DISPLAY_PRINT 1847 For ARM, enable an optional function to print more information 1848 about the running system. 1849 1850 CONFIG_SPL_INIT_MINIMAL 1851 Arch init code should be built for a very small image 1852 1853 CONFIG_SYS_MMCSD_RAW_MODE_ARGS_SECTOR, 1854 CONFIG_SYS_MMCSD_RAW_MODE_ARGS_SECTORS 1855 Sector and number of sectors to load kernel argument 1856 parameters from when MMC is being used in raw mode 1857 (for falcon mode) 1858 1859 CONFIG_SPL_FS_LOAD_PAYLOAD_NAME 1860 Filename to read to load U-Boot when reading from filesystem 1861 1862 CONFIG_SPL_FS_LOAD_KERNEL_NAME 1863 Filename to read to load kernel uImage when reading 1864 from filesystem (for Falcon mode) 1865 1866 CONFIG_SPL_FS_LOAD_ARGS_NAME 1867 Filename to read to load kernel argument parameters 1868 when reading from filesystem (for Falcon mode) 1869 1870 CONFIG_SPL_MPC83XX_WAIT_FOR_NAND 1871 Set this for NAND SPL on PPC mpc83xx targets, so that 1872 start.S waits for the rest of the SPL to load before 1873 continuing (the hardware starts execution after just 1874 loading the first page rather than the full 4K). 1875 1876 CONFIG_SPL_SKIP_RELOCATE 1877 Avoid SPL relocation 1878 1879 CONFIG_SPL_NAND_IDENT 1880 SPL uses the chip ID list to identify the NAND flash. 1881 Requires CONFIG_SPL_NAND_BASE. 1882 1883 CONFIG_SPL_UBI 1884 Support for a lightweight UBI (fastmap) scanner and 1885 loader 1886 1887 CONFIG_SPL_NAND_RAW_ONLY 1888 Support to boot only raw u-boot.bin images. Use this only 1889 if you need to save space. 1890 1891 CONFIG_SPL_COMMON_INIT_DDR 1892 Set for common ddr init with serial presence detect in 1893 SPL binary. 1894 1895 CONFIG_SYS_NAND_5_ADDR_CYCLE, CONFIG_SYS_NAND_PAGE_COUNT, 1896 CONFIG_SYS_NAND_PAGE_SIZE, CONFIG_SYS_NAND_OOBSIZE, 1897 CONFIG_SYS_NAND_BLOCK_SIZE, CONFIG_SYS_NAND_BAD_BLOCK_POS, 1898 CONFIG_SYS_NAND_ECCPOS, CONFIG_SYS_NAND_ECCSIZE, 1899 CONFIG_SYS_NAND_ECCBYTES 1900 Defines the size and behavior of the NAND that SPL uses 1901 to read U-Boot 1902 1903 CONFIG_SYS_NAND_U_BOOT_DST 1904 Location in memory to load U-Boot to 1905 1906 CONFIG_SYS_NAND_U_BOOT_SIZE 1907 Size of image to load 1908 1909 CONFIG_SYS_NAND_U_BOOT_START 1910 Entry point in loaded image to jump to 1911 1912 CONFIG_SYS_NAND_HW_ECC_OOBFIRST 1913 Define this if you need to first read the OOB and then the 1914 data. This is used, for example, on davinci platforms. 1915 1916 CONFIG_SPL_RAM_DEVICE 1917 Support for running image already present in ram, in SPL binary 1918 1919 CONFIG_SPL_PAD_TO 1920 Image offset to which the SPL should be padded before appending 1921 the SPL payload. By default, this is defined as 1922 CONFIG_SPL_MAX_SIZE, or 0 if CONFIG_SPL_MAX_SIZE is undefined. 1923 CONFIG_SPL_PAD_TO must be either 0, meaning to append the SPL 1924 payload without any padding, or >= CONFIG_SPL_MAX_SIZE. 1925 1926 CONFIG_SPL_TARGET 1927 Final target image containing SPL and payload. Some SPLs 1928 use an arch-specific makefile fragment instead, for 1929 example if more than one image needs to be produced. 1930 1931 CONFIG_SPL_FIT_PRINT 1932 Printing information about a FIT image adds quite a bit of 1933 code to SPL. So this is normally disabled in SPL. Use this 1934 option to re-enable it. This will affect the output of the 1935 bootm command when booting a FIT image. 1936 1937- TPL framework 1938 CONFIG_TPL 1939 Enable building of TPL globally. 1940 1941 CONFIG_TPL_PAD_TO 1942 Image offset to which the TPL should be padded before appending 1943 the TPL payload. By default, this is defined as 1944 CONFIG_SPL_MAX_SIZE, or 0 if CONFIG_SPL_MAX_SIZE is undefined. 1945 CONFIG_SPL_PAD_TO must be either 0, meaning to append the SPL 1946 payload without any padding, or >= CONFIG_SPL_MAX_SIZE. 1947 1948- Interrupt support (PPC): 1949 1950 There are common interrupt_init() and timer_interrupt() 1951 for all PPC archs. interrupt_init() calls interrupt_init_cpu() 1952 for CPU specific initialization. interrupt_init_cpu() 1953 should set decrementer_count to appropriate value. If 1954 CPU resets decrementer automatically after interrupt 1955 (ppc4xx) it should set decrementer_count to zero. 1956 timer_interrupt() calls timer_interrupt_cpu() for CPU 1957 specific handling. If board has watchdog / status_led 1958 / other_activity_monitor it works automatically from 1959 general timer_interrupt(). 1960 1961 1962Board initialization settings: 1963------------------------------ 1964 1965During Initialization u-boot calls a number of board specific functions 1966to allow the preparation of board specific prerequisites, e.g. pin setup 1967before drivers are initialized. To enable these callbacks the 1968following configuration macros have to be defined. Currently this is 1969architecture specific, so please check arch/your_architecture/lib/board.c 1970typically in board_init_f() and board_init_r(). 1971 1972- CONFIG_BOARD_EARLY_INIT_F: Call board_early_init_f() 1973- CONFIG_BOARD_EARLY_INIT_R: Call board_early_init_r() 1974- CONFIG_BOARD_LATE_INIT: Call board_late_init() 1975- CONFIG_BOARD_POSTCLK_INIT: Call board_postclk_init() 1976 1977Configuration Settings: 1978----------------------- 1979 1980- MEM_SUPPORT_64BIT_DATA: Defined automatically if compiled as 64-bit. 1981 Optionally it can be defined to support 64-bit memory commands. 1982 1983- CONFIG_SYS_LONGHELP: Defined when you want long help messages included; 1984 undefine this when you're short of memory. 1985 1986- CONFIG_SYS_HELP_CMD_WIDTH: Defined when you want to override the default 1987 width of the commands listed in the 'help' command output. 1988 1989- CONFIG_SYS_PROMPT: This is what U-Boot prints on the console to 1990 prompt for user input. 1991 1992- CONFIG_SYS_CBSIZE: Buffer size for input from the Console 1993 1994- CONFIG_SYS_PBSIZE: Buffer size for Console output 1995 1996- CONFIG_SYS_MAXARGS: max. Number of arguments accepted for monitor commands 1997 1998- CONFIG_SYS_BARGSIZE: Buffer size for Boot Arguments which are passed to 1999 the application (usually a Linux kernel) when it is 2000 booted
2001 2002- CONFIG_SYS_BAUDRATE_TABLE: 2003 List of legal baudrate settings for this board. 2004 2005- CONFIG_SYS_MEM_RESERVE_SECURE 2006 Only implemented for ARMv8 for now. 2007 If defined, the size of CONFIG_SYS_MEM_RESERVE_SECURE memory 2008 is substracted from total RAM and won't be reported to OS. 2009 This memory can be used as secure memory. A variable 2010 gd->arch.secure_ram is used to track the location. In systems 2011 the RAM base is not zero, or RAM is divided into banks, 2012 this variable needs to be recalcuated to get the address. 2013 2014- CONFIG_SYS_MEM_TOP_HIDE: 2015 If CONFIG_SYS_MEM_TOP_HIDE is defined in the board config header, 2016 this specified memory area will get subtracted from the top 2017 (end) of RAM and won't get "touched" at all by U-Boot. By 2018 fixing up gd->ram_size the Linux kernel should gets passed 2019 the now "corrected" memory size and won't touch it either. 2020 This should work for arch/ppc and arch/powerpc. Only Linux 2021 board ports in arch/powerpc with bootwrapper support that 2022 recalculate the memory size from the SDRAM controller setup 2023 will have to get fixed in Linux additionally. 2024 2025 This option can be used as a workaround for the 440EPx/GRx 2026 CHIP 11 errata where the last 256 bytes in SDRAM shouldn't 2027 be touched. 2028 2029 WARNING: Please make sure that this value is a multiple of 2030 the Linux page size (normally 4k). If this is not the case, 2031 then the end address of the Linux memory will be located at a 2032 non page size aligned address and this could cause major 2033 problems. 2034 2035- CONFIG_SYS_LOADS_BAUD_CHANGE: 2036 Enable temporary baudrate change while serial download 2037 2038- CONFIG_SYS_SDRAM_BASE: 2039 Physical start address of SDRAM. _Must_ be 0 here. 2040 2041- CONFIG_SYS_FLASH_BASE: 2042 Physical start address of Flash memory. 2043 2044- CONFIG_SYS_MONITOR_BASE: 2045 Physical start address of boot monitor code (set by 2046 make config files to be same as the text base address 2047 (CONFIG_SYS_TEXT_BASE) used when linking) - same as 2048 CONFIG_SYS_FLASH_BASE when booting from flash. 2049 2050- CONFIG_SYS_MONITOR_LEN: 2051 Size of memory reserved for monitor code, used to 2052 determine _at_compile_time_ (!) if the environment is 2053 embedded within the U-Boot image, or in a separate 2054 flash sector. 2055 2056- CONFIG_SYS_MALLOC_LEN: 2057 Size of DRAM reserved for malloc() use. 2058 2059- CONFIG_SYS_MALLOC_F_LEN 2060 Size of the malloc() pool for use before relocation. If 2061 this is defined, then a very simple malloc() implementation 2062 will become available before relocation. The address is just 2063 below the global data, and the stack is moved down to make 2064 space. 2065 2066 This feature allocates regions with increasing addresses 2067 within the region. calloc() is supported, but realloc() 2068 is not available. free() is supported but does nothing. 2069 The memory will be freed (or in fact just forgotten) when 2070 U-Boot relocates itself. 2071 2072- CONFIG_SYS_MALLOC_SIMPLE 2073 Provides a simple and small malloc() and calloc() for those 2074 boards which do not use the full malloc in SPL (which is 2075 enabled with CONFIG_SYS_SPL_MALLOC_START). 2076 2077- CONFIG_SYS_NONCACHED_MEMORY: 2078 Size of non-cached memory area. This area of memory will be 2079 typically located right below the malloc() area and mapped 2080 uncached in the MMU. This is useful for drivers that would 2081 otherwise require a lot of explicit cache maintenance. For 2082 some drivers it's also impossible to properly maintain the 2083 cache. For example if the regions that need to be flushed 2084 are not a multiple of the cache-line size, *and* padding 2085 cannot be allocated between the regions to align them (i.e. 2086 if the HW requires a contiguous array of regions, and the 2087 size of each region is not cache-aligned), then a flush of 2088 one region may result in overwriting data that hardware has 2089 written to another region in the same cache-line. This can 2090 happen for example in network drivers where descriptors for 2091 buffers are typically smaller than the CPU cache-line (e.g. 2092 16 bytes vs. 32 or 64 bytes). 2093 2094 Non-cached memory is only supported on 32-bit ARM at present. 2095 2096- CONFIG_SYS_BOOTM_LEN: 2097 Normally compressed uImages are limited to an 2098 uncompressed size of 8 MBytes. If this is not enough, 2099 you can define CONFIG_SYS_BOOTM_LEN in your board config file 2100 to adjust this setting to your needs. 2101 2102- CONFIG_SYS_BOOTMAPSZ: 2103 Maximum size of memory mapped by the startup code of 2104 the Linux kernel; all data that must be processed by 2105 the Linux kernel (bd_info, boot arguments, FDT blob if 2106 used) must be put below this limit, unless "bootm_low" 2107 environment variable is defined and non-zero. In such case 2108 all data for the Linux kernel must be between "bootm_low" 2109 and "bootm_low" + CONFIG_SYS_BOOTMAPSZ. The environment 2110 variable "bootm_mapsize" will override the value of 2111 CONFIG_SYS_BOOTMAPSZ. If CONFIG_SYS_BOOTMAPSZ is undefined, 2112 then the value in "bootm_size" will be used instead. 2113 2114- CONFIG_SYS_BOOT_RAMDISK_HIGH: 2115 Enable initrd_high functionality. If defined then the 2116 initrd_high feature is enabled and the bootm ramdisk subcommand 2117 is enabled. 2118 2119- CONFIG_SYS_BOOT_GET_CMDLINE: 2120 Enables allocating and saving kernel cmdline in space between 2121 "bootm_low" and "bootm_low" + BOOTMAPSZ. 2122 2123- CONFIG_SYS_BOOT_GET_KBD: 2124 Enables allocating and saving a kernel copy of the bd_info in 2125 space between "bootm_low" and "bootm_low" + BOOTMAPSZ. 2126 2127- CONFIG_SYS_MAX_FLASH_SECT: 2128 Max number of sectors on a Flash chip 2129 2130- CONFIG_SYS_FLASH_ERASE_TOUT: 2131 Timeout for Flash erase operations (in ms) 2132 2133- CONFIG_SYS_FLASH_WRITE_TOUT: 2134 Timeout for Flash write operations (in ms) 2135 2136- CONFIG_SYS_FLASH_LOCK_TOUT 2137 Timeout for Flash set sector lock bit operation (in ms) 2138 2139- CONFIG_SYS_FLASH_UNLOCK_TOUT 2140 Timeout for Flash clear lock bits operation (in ms) 2141 2142- CONFIG_SYS_FLASH_PROTECTION 2143 If defined, hardware flash sectors protection is used 2144 instead of U-Boot software protection. 2145 2146- CONFIG_SYS_DIRECT_FLASH_TFTP: 2147 2148 Enable TFTP transfers directly to flash memory; 2149 without this option such a download has to be 2150 performed in two steps: (1) download to RAM, and (2) 2151 copy from RAM to flash. 2152 2153 The two-step approach is usually more reliable, since 2154 you can check if the download worked before you erase 2155 the flash, but in some situations (when system RAM is 2156 too limited to allow for a temporary copy of the 2157 downloaded image) this option may be very useful. 2158 2159- CONFIG_SYS_FLASH_CFI: 2160 Define if the flash driver uses extra elements in the 2161 common flash structure for storing flash geometry. 2162 2163- CONFIG_FLASH_CFI_DRIVER 2164 This option also enables the building of the cfi_flash driver 2165 in the drivers directory 2166 2167- CONFIG_FLASH_CFI_MTD 2168 This option enables the building of the cfi_mtd driver 2169 in the drivers directory. The driver exports CFI flash 2170 to the MTD layer. 2171 2172- CONFIG_SYS_FLASH_USE_BUFFER_WRITE 2173 Use buffered writes to flash. 2174 2175- CONFIG_FLASH_SPANSION_S29WS_N 2176 s29ws-n MirrorBit flash has non-standard addresses for buffered 2177 write commands. 2178 2179- CONFIG_SYS_FLASH_QUIET_TEST 2180 If this option is defined, the common CFI flash doesn't 2181 print it's warning upon not recognized FLASH banks. This 2182 is useful, if some of the configured banks are only 2183 optionally available. 2184 2185- CONFIG_FLASH_SHOW_PROGRESS 2186 If defined (must be an integer), print out countdown 2187 digits and dots. Recommended value: 45 (9..1) for 80 2188 column displays, 15 (3..1) for 40 column displays. 2189 2190- CONFIG_FLASH_VERIFY 2191 If defined, the content of the flash (destination) is compared 2192 against the source after the write operation. An error message 2193 will be printed when the contents are not identical. 2194 Please note that this option is useless in nearly all cases, 2195 since such flash programming errors usually are detected earlier 2196 while unprotecting/erasing/programming. Please only enable 2197 this option if you really know what you are doing. 2198 2199- CONFIG_SYS_RX_ETH_BUFFER: 2200 Defines the number of Ethernet receive buffers. On some 2201 Ethernet controllers it is recommended to set this value 2202 to 8 or even higher (EEPRO100 or 405 EMAC), since all 2203 buffers can be full shortly after enabling the interface 2204 on high Ethernet traffic. 2205 Defaults to 4 if not defined. 2206 2207- CONFIG_ENV_MAX_ENTRIES 2208 2209 Maximum number of entries in the hash table that is used 2210 internally to store the environment settings. The default 2211 setting is supposed to be generous and should work in most 2212 cases. This setting can be used to tune behaviour; see 2213 lib/hashtable.c for details. 2214 2215- CONFIG_ENV_FLAGS_LIST_DEFAULT 2216- CONFIG_ENV_FLAGS_LIST_STATIC 2217 Enable validation of the values given to environment variables when 2218 calling env set. Variables can be restricted to only decimal, 2219 hexadecimal, or boolean. If CONFIG_CMD_NET is also defined, 2220 the variables can also be restricted to IP address or MAC address. 2221 2222 The format of the list is: 2223 type_attribute = [s|d|x|b|i|m] 2224 access_attribute = [a|r|o|c] 2225 attributes = type_attribute[access_attribute] 2226 entry = variable_name[:attributes] 2227 list = entry[,list] 2228 2229 The type attributes are: 2230 s - String (default) 2231 d - Decimal 2232 x - Hexadecimal 2233 b - Boolean ([1yYtT|0nNfF]) 2234 i - IP address 2235 m - MAC address 2236 2237 The access attributes are: 2238 a - Any (default) 2239 r - Read-only 2240 o - Write-once 2241 c - Change-default 2242 2243 - CONFIG_ENV_FLAGS_LIST_DEFAULT 2244 Define this to a list (string) to define the ".flags" 2245 environment variable in the default or embedded environment. 2246 2247 - CONFIG_ENV_FLAGS_LIST_STATIC 2248 Define this to a list (string) to define validation that 2249 should be done if an entry is not found in the ".flags" 2250 environment variable. To override a setting in the static 2251 list, simply add an entry for the same variable name to the 2252 ".flags" variable. 2253 2254 If CONFIG_REGEX is defined, the variable_name above is evaluated as a 2255 regular expression. This allows multiple variables to define the same 2256 flags without explicitly listing them for each variable. 2257 2258The following definitions that deal with the placement and management 2259of environment data (variable area); in general, we support the 2260following configurations: 2261 2262- CONFIG_BUILD_ENVCRC: 2263 2264 Builds up envcrc with the target environment so that external utils 2265 may easily extract it and embed it in final U-Boot images. 2266 2267BE CAREFUL! The first access to the environment happens quite early 2268in U-Boot initialization (when we try to get the setting of for the 2269console baudrate). You *MUST* have mapped your NVRAM area then, or 2270U-Boot will hang. 2271 2272Please note that even with NVRAM we still use a copy of the 2273environment in RAM: we could work on NVRAM directly, but we want to 2274keep settings there always unmodified except somebody uses "saveenv" 2275to save the current settings. 2276 2277BE CAREFUL! For some special cases, the local device can not use 2278"saveenv" command. For example, the local device will get the 2279environment stored in a remote NOR flash by SRIO or PCIE link, 2280but it can not erase, write this NOR flash by SRIO or PCIE interface. 2281 2282- CONFIG_NAND_ENV_DST 2283 2284 Defines address in RAM to which the nand_spl code should copy the 2285 environment. If redundant environment is used, it will be copied to 2286 CONFIG_NAND_ENV_DST + CONFIG_ENV_SIZE. 2287 2288Please note that the environment is read-only until the monitor 2289has been relocated to RAM and a RAM copy of the environment has been 2290created; also, when using EEPROM you will have to use env_get_f() 2291until then to read environment variables. 2292 2293The environment is protected by a CRC32 checksum. Before the monitor 2294is relocated into RAM, as a result of a bad CRC you will be working 2295with the compiled-in default environment - *silently*!!! [This is 2296necessary, because the first environment variable we need is the 2297"baudrate" setting for the console - if we have a bad CRC, we don't 2298have any device yet where we could complain.] 2299 2300Note: once the monitor has been relocated, then it will complain if 2301the default environment is used; a new CRC is computed as soon as you 2302use the "saveenv" command to store a valid environment. 2303 2304- CONFIG_SYS_FAULT_ECHO_LINK_DOWN: 2305 Echo the inverted Ethernet link state to the fault LED. 2306 2307 Note: If this option is active, then CONFIG_SYS_FAULT_MII_ADDR 2308 also needs to be defined. 2309 2310- CONFIG_SYS_FAULT_MII_ADDR: 2311 MII address of the PHY to check for the Ethernet link state. 2312 2313- CONFIG_NS16550_MIN_FUNCTIONS: 2314 Define this if you desire to only have use of the NS16550_init 2315 and NS16550_putc functions for the serial driver located at 2316 drivers/serial/ns16550.c. This option is useful for saving 2317 space for already greatly restricted images, including but not 2318 limited to NAND_SPL configurations. 2319 2320- CONFIG_DISPLAY_BOARDINFO 2321 Display information about the board that U-Boot is running on 2322 when U-Boot starts up. The board function checkboard() is called 2323 to do this. 2324 2325- CONFIG_DISPLAY_BOARDINFO_LATE 2326 Similar to the previous option, but display this information 2327 later, once stdio is running and output goes to the LCD, if 2328 present. 2329 2330- CONFIG_BOARD_SIZE_LIMIT: 2331 Maximum size of the U-Boot image. When defined, the 2332 build system checks that the actual size does not 2333 exceed it. 2334 2335Low Level (hardware related) configuration options: 2336--------------------------------------------------- 2337 2338- CONFIG_SYS_CACHELINE_SIZE: 2339 Cache Line Size of the CPU. 2340 2341- CONFIG_SYS_CCSRBAR_DEFAULT: 2342 Default (power-on reset) physical address of CCSR on Freescale 2343 PowerPC SOCs. 2344 2345- CONFIG_SYS_CCSRBAR: 2346 Virtual address of CCSR. On a 32-bit build, this is typically 2347 the same value as CONFIG_SYS_CCSRBAR_DEFAULT. 2348 2349- CONFIG_SYS_CCSRBAR_PHYS: 2350 Physical address of CCSR. CCSR can be relocated to a new 2351 physical address, if desired. In this case, this macro should 2352 be set to that address. Otherwise, it should be set to the 2353 same value as CONFIG_SYS_CCSRBAR_DEFAULT. For example, CCSR 2354 is typically relocated on 36-bit builds. It is recommended 2355 that this macro be defined via the _HIGH and _LOW macros: 2356 2357 #define CONFIG_SYS_CCSRBAR_PHYS ((CONFIG_SYS_CCSRBAR_PHYS_HIGH 2358 * 1ull) << 32 | CONFIG_SYS_CCSRBAR_PHYS_LOW) 2359 2360- CONFIG_SYS_CCSRBAR_PHYS_HIGH: 2361 Bits 33-36 of CONFIG_SYS_CCSRBAR_PHYS. This value is typically 2362 either 0 (32-bit build) or 0xF (36-bit build). This macro is 2363 used in assembly code, so it must not contain typecasts or 2364 integer size suffixes (e.g. "ULL"). 2365 2366- CONFIG_SYS_CCSRBAR_PHYS_LOW: 2367 Lower 32-bits of CONFIG_SYS_CCSRBAR_PHYS. This macro is 2368 used in assembly code, so it must not contain typecasts or 2369 integer size suffixes (e.g. "ULL"). 2370 2371- CONFIG_SYS_CCSR_DO_NOT_RELOCATE: 2372 If this macro is defined, then CONFIG_SYS_CCSRBAR_PHYS will be 2373 forced to a value that ensures that CCSR is not relocated. 2374 2375- CONFIG_SYS_IMMR: Physical address of the Internal Memory. 2376 DO NOT CHANGE unless you know exactly what you're 2377 doing! (11-4) [MPC8xx systems only] 2378 2379- CONFIG_SYS_INIT_RAM_ADDR: 2380 2381 Start address of memory area that can be used for 2382 initial data and stack; please note that this must be 2383 writable memory that is working WITHOUT special 2384 initialization, i. e. you CANNOT use normal RAM which 2385 will become available only after programming the 2386 memory controller and running certain initialization 2387 sequences. 2388 2389 U-Boot uses the following memory types: 2390 - MPC8xx: IMMR (internal memory of the CPU) 2391 2392- CONFIG_SYS_GBL_DATA_OFFSET: 2393 2394 Offset of the initial data structure in the memory 2395 area defined by CONFIG_SYS_INIT_RAM_ADDR. Usually 2396 CONFIG_SYS_GBL_DATA_OFFSET is chosen such that the initial 2397 data is located at the end of the available space 2398 (sometimes written as (CONFIG_SYS_INIT_RAM_SIZE - 2399 GENERATED_GBL_DATA_SIZE), and the initial stack is just 2400 below that area (growing from (CONFIG_SYS_INIT_RAM_ADDR + 2401 CONFIG_SYS_GBL_DATA_OFFSET) downward. 2402 2403 Note: 2404 On the MPC824X (or other systems that use the data 2405 cache for initial memory) the address chosen for 2406 CONFIG_SYS_INIT_RAM_ADDR is basically arbitrary - it must 2407 point to an otherwise UNUSED address space between 2408 the top of RAM and the start of the PCI space. 2409 2410- CONFIG_SYS_SCCR: System Clock and reset Control Register (15-27) 2411 2412- CONFIG_SYS_OR_TIMING_SDRAM: 2413 SDRAM timing 2414 2415- CONFIG_SYS_MAMR_PTA: 2416 periodic timer for refresh 2417 2418- CONFIG_SYS_SRIO: 2419 Chip has SRIO or not 2420 2421- CONFIG_SRIO1: 2422 Board has SRIO 1 port available 2423 2424- CONFIG_SRIO2: 2425 Board has SRIO 2 port available 2426 2427- CONFIG_SRIO_PCIE_BOOT_MASTER 2428 Board can support master function for Boot from SRIO and PCIE 2429 2430- CONFIG_SYS_SRIOn_MEM_VIRT: 2431 Virtual Address of SRIO port 'n' memory region 2432 2433- CONFIG_SYS_SRIOn_MEM_PHYxS: 2434 Physical Address of SRIO port 'n' memory region 2435 2436- CONFIG_SYS_SRIOn_MEM_SIZE: 2437 Size of SRIO port 'n' memory region 2438 2439- CONFIG_SYS_NAND_BUSWIDTH_16BIT 2440 Defined to tell the NAND controller that the NAND chip is using 2441 a 16 bit bus. 2442 Not all NAND drivers use this symbol. 2443 Example of drivers that use it: 2444 - drivers/mtd/nand/raw/ndfc.c 2445 - drivers/mtd/nand/raw/mxc_nand.c 2446 2447- CONFIG_SYS_NDFC_EBC0_CFG 2448 Sets the EBC0_CFG register for the NDFC. If not defined 2449 a default value will be used. 2450 2451- CONFIG_SPD_EEPROM 2452 Get DDR timing information from an I2C EEPROM. Common 2453 with pluggable memory modules such as SODIMMs 2454 2455 SPD_EEPROM_ADDRESS 2456 I2C address of the SPD EEPROM 2457 2458- CONFIG_SYS_SPD_BUS_NUM 2459 If SPD EEPROM is on an I2C bus other than the first 2460 one, specify here. Note that the value must resolve 2461 to something your driver can deal with. 2462 2463- CONFIG_SYS_DDR_RAW_TIMING 2464 Get DDR timing information from other than SPD. Common with 2465 soldered DDR chips onboard without SPD. DDR raw timing 2466 parameters are extracted from datasheet and hard-coded into 2467 header files or board specific files. 2468 2469- CONFIG_FSL_DDR_INTERACTIVE 2470 Enable interactive DDR debugging. See doc/README.fsl-ddr. 2471 2472- CONFIG_FSL_DDR_SYNC_REFRESH 2473 Enable sync of refresh for multiple controllers. 2474 2475- CONFIG_FSL_DDR_BIST 2476 Enable built-in memory test for Freescale DDR controllers. 2477 2478- CONFIG_SYS_83XX_DDR_USES_CS0 2479 Only for 83xx systems. If specified, then DDR should 2480 be configured using CS0 and CS1 instead of CS2 and CS3. 2481 2482- CONFIG_RMII 2483 Enable RMII mode for all FECs. 2484 Note that this is a global option, we can't 2485 have one FEC in standard MII mode and another in RMII mode. 2486 2487- CONFIG_CRC32_VERIFY 2488 Add a verify option to the crc32 command. 2489 The syntax is: 2490 2491 => crc32 -v <address> <count> <crc32> 2492 2493 Where address/count indicate a memory area 2494 and crc32 is the correct crc32 which the 2495 area should have. 2496 2497- CONFIG_LOOPW 2498 Add the "loopw" memory command. This only takes effect if 2499 the memory commands are activated globally (CONFIG_CMD_MEMORY). 2500 2501- CONFIG_CMD_MX_CYCLIC 2502 Add the "mdc" and "mwc" memory commands. These are cyclic 2503 "md/mw" commands. 2504 Examples: 2505 2506 => mdc.b 10 4 500 2507 This command will print 4 bytes (10,11,12,13) each 500 ms. 2508 2509 => mwc.l 100 12345678 10 2510 This command will write 12345678 to address 100 all 10 ms. 2511 2512 This only takes effect if the memory commands are activated 2513 globally (CONFIG_CMD_MEMORY). 2514 2515- CONFIG_SPL_BUILD 2516 Set when the currently-running compilation is for an artifact 2517 that will end up in the SPL (as opposed to the TPL or U-Boot 2518 proper). Code that needs stage-specific behavior should check 2519 this. 2520 2521- CONFIG_TPL_BUILD 2522 Set when the currently-running compilation is for an artifact 2523 that will end up in the TPL (as opposed to the SPL or U-Boot 2524 proper). Code that needs stage-specific behavior should check 2525 this. 2526 2527- CONFIG_SYS_MPC85XX_NO_RESETVEC 2528 Only for 85xx systems. If this variable is specified, the section 2529 .resetvec is not kept and the section .bootpg is placed in the 2530 previous 4k of the .text section. 2531 2532- CONFIG_ARCH_MAP_SYSMEM 2533 Generally U-Boot (and in particular the md command) uses 2534 effective address. It is therefore not necessary to regard 2535 U-Boot address as virtual addresses that need to be translated 2536 to physical addresses. However, sandbox requires this, since 2537 it maintains its own little RAM buffer which contains all 2538 addressable memory. This option causes some memory accesses 2539 to be mapped through map_sysmem() / unmap_sysmem(). 2540 2541- CONFIG_X86_RESET_VECTOR 2542 If defined, the x86 reset vector code is included. This is not 2543 needed when U-Boot is running from Coreboot. 2544 2545- CONFIG_SYS_NAND_NO_SUBPAGE_WRITE 2546 Option to disable subpage write in NAND driver 2547 driver that uses this: 2548 drivers/mtd/nand/raw/davinci_nand.c 2549 2550Freescale QE/FMAN Firmware Support: 2551----------------------------------- 2552 2553The Freescale QUICCEngine (QE) and Frame Manager (FMAN) both support the 2554loading of "firmware", which is encoded in the QE firmware binary format. 2555This firmware often needs to be loaded during U-Boot booting, so macros 2556are used to identify the storage device (NOR flash, SPI, etc) and the address 2557within that device. 2558 2559- CONFIG_SYS_FMAN_FW_ADDR 2560 The address in the storage device where the FMAN microcode is located. The 2561 meaning of this address depends on which CONFIG_SYS_QE_FMAN_FW_IN_xxx macro 2562 is also specified. 2563 2564- CONFIG_SYS_QE_FW_ADDR 2565 The address in the storage device where the QE microcode is located. The 2566 meaning of this address depends on which CONFIG_SYS_QE_FMAN_FW_IN_xxx macro 2567 is also specified. 2568 2569- CONFIG_SYS_QE_FMAN_FW_LENGTH 2570 The maximum possible size of the firmware. The firmware binary format 2571 has a field that specifies the actual size of the firmware, but it 2572 might not be possible to read any part of the firmware unless some 2573 local storage is allocated to hold the entire firmware first. 2574 2575- CONFIG_SYS_QE_FMAN_FW_IN_NOR 2576 Specifies that QE/FMAN firmware is located in NOR flash, mapped as 2577 normal addressable memory via the LBC. CONFIG_SYS_FMAN_FW_ADDR is the 2578 virtual address in NOR flash. 2579 2580- CONFIG_SYS_QE_FMAN_FW_IN_NAND 2581 Specifies that QE/FMAN firmware is located in NAND flash. 2582 CONFIG_SYS_FMAN_FW_ADDR is the offset within NAND flash. 2583 2584- CONFIG_SYS_QE_FMAN_FW_IN_MMC 2585 Specifies that QE/FMAN firmware is located on the primary SD/MMC 2586 device. CONFIG_SYS_FMAN_FW_ADDR is the byte offset on that device. 2587 2588- CONFIG_SYS_QE_FMAN_FW_IN_REMOTE 2589 Specifies that QE/FMAN firmware is located in the remote (master) 2590 memory space. CONFIG_SYS_FMAN_FW_ADDR is a virtual address which 2591 can be mapped from slave TLB->slave LAW->slave SRIO or PCIE outbound 2592 window->master inbound window->master LAW->the ucode address in 2593 master's memory space. 2594 2595Freescale Layerscape Management Complex Firmware Support: 2596--------------------------------------------------------- 2597The Freescale Layerscape Management Complex (MC) supports the loading of 2598"firmware". 2599This firmware often needs to be loaded during U-Boot booting, so macros 2600are used to identify the storage device (NOR flash, SPI, etc) and the address 2601within that device. 2602 2603- CONFIG_FSL_MC_ENET 2604 Enable the MC driver for Layerscape SoCs. 2605 2606Freescale Layerscape Debug Server Support: 2607------------------------------------------- 2608The Freescale Layerscape Debug Server Support supports the loading of 2609"Debug Server firmware" and triggering SP boot-rom. 2610This firmware often needs to be loaded during U-Boot booting. 2611 2612- CONFIG_SYS_MC_RSV_MEM_ALIGN 2613 Define alignment of reserved memory MC requires 2614 2615Reproducible builds 2616------------------- 2617 2618In order to achieve reproducible builds, timestamps used in the U-Boot build 2619process have to be set to a fixed value. 2620 2621This is done using the SOURCE_DATE_EPOCH environment variable. 2622SOURCE_DATE_EPOCH is to be set on the build host's shell, not as a configuration 2623option for U-Boot or an environment variable in U-Boot. 2624 2625SOURCE_DATE_EPOCH should be set to a number of seconds since the epoch, in UTC. 2626 2627Building the Software: 2628====================== 2629 2630Building U-Boot has been tested in several native build environments 2631and in many different cross environments. Of course we cannot support 2632all possibly existing versions of cross development tools in all 2633(potentially obsolete) versions. In case of tool chain problems we 2634recommend to use the ELDK (see https://www.denx.de/wiki/DULG/ELDK) 2635which is extensively used to build and test U-Boot. 2636 2637If you are not using a native environment, it is assumed that you 2638have GNU cross compiling tools available in your path. In this case, 2639you must set the environment variable CROSS_COMPILE in your shell. 2640Note that no changes to the Makefile or any other source files are 2641necessary. For example using the ELDK on a 4xx CPU, please enter: 2642 2643 $ CROSS_COMPILE=ppc_4xx- 2644 $ export CROSS_COMPILE 2645 2646U-Boot is intended to be simple to build. After installing the 2647sources you must configure U-Boot for one specific board type. This 2648is done by typing: 2649 2650 make NAME_defconfig 2651 2652where "NAME_defconfig" is the name of one of the existing configu- 2653rations; see configs/*_defconfig for supported names. 2654 2655Note: for some boards special configuration names may exist; check if 2656 additional information is available from the board vendor; for 2657 instance, the TQM823L systems are available without (standard) 2658 or with LCD support. You can select such additional "features" 2659 when choosing the configuration, i. e. 2660 2661 make TQM823L_defconfig 2662 - will configure for a plain TQM823L, i. e. no LCD support 2663 2664 make TQM823L_LCD_defconfig 2665 - will configure for a TQM823L with U-Boot console on LCD 2666 2667 etc. 2668 2669 2670Finally, type "make all", and you should get some working U-Boot 2671images ready for download to / installation on your system: 2672 2673- "u-boot.bin" is a raw binary image 2674- "u-boot" is an image in ELF binary format 2675- "u-boot.srec" is in Motorola S-Record format 2676 2677By default the build is performed locally and the objects are saved 2678in the source directory. One of the two methods can be used to change 2679this behavior and build U-Boot to some external directory: 2680 26811. Add O= to the make command line invocations: 2682 2683 make O=/tmp/build distclean 2684 make O=/tmp/build NAME_defconfig 2685 make O=/tmp/build all 2686 26872. Set environment variable KBUILD_OUTPUT to point to the desired location: 2688 2689 export KBUILD_OUTPUT=/tmp/build 2690 make distclean 2691 make NAME_defconfig 2692 make all 2693 2694Note that the command line "O=" setting overrides the KBUILD_OUTPUT environment 2695variable. 2696 2697User specific CPPFLAGS, AFLAGS and CFLAGS can be passed to the compiler by 2698setting the according environment variables KCPPFLAGS, KAFLAGS and KCFLAGS. 2699For example to treat all compiler warnings as errors: 2700 2701 make KCFLAGS=-Werror 2702 2703Please be aware that the Makefiles assume you are using GNU make, so 2704for instance on NetBSD you might need to use "gmake" instead of 2705native "make". 2706 2707 2708If the system board that you have is not listed, then you will need 2709to port U-Boot to your hardware platform. To do this, follow these 2710steps: 2711 27121. Create a new directory to hold your board specific code. Add any 2713 files you need. In your board directory, you will need at least 2714 the "Makefile" and a "<board>.c". 27152. Create a new configuration file "include/configs/<board>.h" for 2716 your board. 27173. If you're porting U-Boot to a new CPU, then also create a new 2718 directory to hold your CPU specific code. Add any files you need. 27194. Run "make <board>_defconfig" with your new name. 27205. Type "make", and you should get a working "u-boot.srec" file 2721 to be installed on your target system. 27226. Debug and solve any problems that might arise. 2723 [Of course, this last step is much harder than it sounds.] 2724 2725 2726Testing of U-Boot Modifications, Ports to New Hardware, etc.: 2727============================================================== 2728 2729If you have modified U-Boot sources (for instance added a new board 2730or support for new devices, a new CPU, etc.) you are expected to 2731provide feedback to the other developers. The feedback normally takes 2732the form of a "patch", i.e. a context diff against a certain (latest 2733official or latest in the git repository) version of U-Boot sources. 2734 2735But before you submit such a patch, please verify that your modifi- 2736cation did not break existing code. At least make sure that *ALL* of 2737the supported boards compile WITHOUT ANY compiler warnings. To do so, 2738just run the buildman script (tools/buildman/buildman), which will 2739configure and build U-Boot for ALL supported system. Be warned, this 2740will take a while. Please see the buildman README, or run 'buildman -H' 2741for documentation. 2742 2743 2744See also "U-Boot Porting Guide" below. 2745 2746 2747Monitor Commands - Overview: 2748============================ 2749 2750go - start application at address 'addr' 2751run - run commands in an environment variable 2752bootm - boot application image from memory 2753bootp - boot image via network using BootP/TFTP protocol 2754bootz - boot zImage from memory 2755tftpboot- boot image via network using TFTP protocol 2756 and env variables "ipaddr" and "serverip" 2757 (and eventually "gatewayip") 2758tftpput - upload a file via network using TFTP protocol 2759rarpboot- boot image via network using RARP/TFTP protocol 2760diskboot- boot from IDE devicebootd - boot default, i.e., run 'bootcmd' 2761loads - load S-Record file over serial line 2762loadb - load binary file over serial line (kermit mode) 2763md - memory display 2764mm - memory modify (auto-incrementing) 2765nm - memory modify (constant address) 2766mw - memory write (fill) 2767ms - memory search 2768cp - memory copy 2769cmp - memory compare 2770crc32 - checksum calculation 2771i2c - I2C sub-system 2772sspi - SPI utility commands 2773base - print or set address offset 2774printenv- print environment variables 2775pwm - control pwm channels 2776setenv - set environment variables 2777saveenv - save environment variables to persistent storage 2778protect - enable or disable FLASH write protection 2779erase - erase FLASH memory 2780flinfo - print FLASH memory information 2781nand - NAND memory operations (see doc/README.nand) 2782bdinfo - print Board Info structure 2783iminfo - print header information for application image 2784coninfo - print console devices and informations 2785ide - IDE sub-system 2786loop - infinite loop on address range 2787loopw - infinite write loop on address range 2788mtest - simple RAM test 2789icache - enable or disable instruction cache 2790dcache - enable or disable data cache 2791reset - Perform RESET of the CPU 2792echo - echo args to console 2793version - print monitor version 2794help - print online help 2795? - alias for 'help' 2796 2797 2798Monitor Commands - Detailed Description: 2799======================================== 2800 2801TODO. 2802 2803For now: just type "help <command>". 2804 2805 2806Note for Redundant Ethernet Interfaces: 2807======================================= 2808 2809Some boards come with redundant Ethernet interfaces; U-Boot supports 2810such configurations and is capable of automatic selection of a 2811"working" interface when needed. MAC assignment works as follows: 2812 2813Network interfaces are numbered eth0, eth1, eth2, ... Corresponding 2814MAC addresses can be stored in the environment as "ethaddr" (=>eth0), 2815"eth1addr" (=>eth1), "eth2addr", ... 2816 2817If the network interface stores some valid MAC address (for instance 2818in SROM), this is used as default address if there is NO correspon- 2819ding setting in the environment; if the corresponding environment 2820variable is set, this overrides the settings in the card; that means: 2821 2822o If the SROM has a valid MAC address, and there is no address in the 2823 environment, the SROM's address is used. 2824 2825o If there is no valid address in the SROM, and a definition in the 2826 environment exists, then the value from the environment variable is 2827 used. 2828 2829o If both the SROM and the environment contain a MAC address, and 2830 both addresses are the same, this MAC address is used. 2831 2832o If both the SROM and the environment contain a MAC address, and the 2833 addresses differ, the value from the environment is used and a 2834 warning is printed. 2835 2836o If neither SROM nor the environment contain a MAC address, an error 2837 is raised. If CONFIG_NET_RANDOM_ETHADDR is defined, then in this case 2838 a random, locally-assigned MAC is used. 2839 2840If Ethernet drivers implement the 'write_hwaddr' function, valid MAC addresses 2841will be programmed into hardware as part of the initialization process. This 2842may be skipped by setting the appropriate 'ethmacskip' environment variable. 2843The naming convention is as follows: 2844"ethmacskip" (=>eth0), "eth1macskip" (=>eth1) etc. 2845 2846Image Formats: 2847============== 2848 2849U-Boot is capable of booting (and performing other auxiliary operations on) 2850images in two formats: 2851 2852New uImage format (FIT) 2853----------------------- 2854 2855Flexible and powerful format based on Flattened Image Tree -- FIT (similar 2856to Flattened Device Tree). It allows the use of images with multiple 2857components (several kernels, ramdisks, etc.), with contents protected by 2858SHA1, MD5 or CRC32. More details are found in the doc/uImage.FIT directory. 2859 2860 2861Old uImage format 2862----------------- 2863 2864Old image format is based on binary files which can be basically anything, 2865preceded by a special header; see the definitions in include/image.h for 2866details; basically, the header defines the following image properties: 2867 2868* Target Operating System (Provisions for OpenBSD, NetBSD, FreeBSD, 2869 4.4BSD, Linux, SVR4, Esix, Solaris, Irix, SCO, Dell, NCR, VxWorks, 2870 LynxOS, pSOS, QNX, RTEMS, INTEGRITY; 2871 Currently supported: Linux, NetBSD, VxWorks, QNX, RTEMS, INTEGRITY). 2872* Target CPU Architecture (Provisions for Alpha, ARM, Intel x86, 2873 IA64, MIPS, NDS32, Nios II, PowerPC, IBM S390, SuperH, Sparc, Sparc 64 Bit; 2874 Currently supported: ARM, Intel x86, MIPS, NDS32, Nios II, PowerPC). 2875* Compression Type (uncompressed, gzip, bzip2) 2876* Load Address 2877* Entry Point 2878* Image Name 2879* Image Timestamp 2880 2881The header is marked by a special Magic Number, and both the header 2882and the data portions of the image are secured against corruption by 2883CRC32 checksums. 2884 2885 2886Linux Support: 2887============== 2888 2889Although U-Boot should support any OS or standalone application 2890easily, the main focus has always been on Linux during the design of 2891U-Boot. 2892 2893U-Boot includes many features that so far have been part of some 2894special "boot loader" code within the Linux kernel. Also, any 2895"initrd" images to be used are no longer part of one big Linux image; 2896instead, kernel and "initrd" are separate images. This implementation 2897serves several purposes: 2898 2899- the same features can be used for other OS or standalone 2900 applications (for instance: using compressed images to reduce the 2901 Flash memory footprint) 2902 2903- it becomes much easier to port new Linux kernel versions because 2904 lots of low-level, hardware dependent stuff are done by U-Boot 2905 2906- the same Linux kernel image can now be used with different "initrd" 2907 images; of course this also means that different kernel images can 2908 be run with the same "initrd". This makes testing easier (you don't 2909 have to build a new "zImage.initrd" Linux image when you just 2910 change a file in your "initrd"). Also, a field-upgrade of the 2911 software is easier now. 2912 2913 2914Linux HOWTO: 2915============ 2916 2917Porting Linux to U-Boot based systems: 2918--------------------------------------- 2919 2920U-Boot cannot save you from doing all the necessary modifications to 2921configure the Linux device drivers for use with your target hardware 2922(no, we don't intend to provide a full virtual machine interface to 2923Linux :-). 2924 2925But now you can ignore ALL boot loader code (in arch/powerpc/mbxboot). 2926 2927Just make sure your machine specific header file (for instance 2928include/asm-ppc/tqm8xx.h) includes the same definition of the Board 2929Information structure as we define in include/asm-<arch>/u-boot.h, 2930and make sure that your definition of IMAP_ADDR uses the same value 2931as your U-Boot configuration in CONFIG_SYS_IMMR. 2932 2933Note that U-Boot now has a driver model, a unified model for drivers. 2934If you are adding a new driver, plumb it into driver model. If there 2935is no uclass available, you are encouraged to create one. See 2936doc/driver-model. 2937 2938 2939Configuring the Linux kernel: 2940----------------------------- 2941 2942No specific requirements for U-Boot. Make sure you have some root 2943device (initial ramdisk, NFS) for your target system. 2944 2945 2946Building a Linux Image: 2947----------------------- 2948 2949With U-Boot, "normal" build targets like "zImage" or "bzImage" are 2950not used. If you use recent kernel source, a new build target 2951"uImage" will exist which automatically builds an image usable by 2952U-Boot. Most older kernels also have support for a "pImage" target, 2953which was introduced for our predecessor project PPCBoot and uses a 2954100% compatible format. 2955 2956Example: 2957 2958 make TQM850L_defconfig 2959 make oldconfig 2960 make dep 2961 make uImage 2962 2963The "uImage" build target uses a special tool (in 'tools/mkimage') to 2964encapsulate a compressed Linux kernel image with header information, 2965CRC32 checksum etc. for use with U-Boot. This is what we are doing: 2966 2967* build a standard "vmlinux" kernel image (in ELF binary format): 2968 2969* convert the kernel into a raw binary image: 2970 2971 ${CROSS_COMPILE}-objcopy -O binary \ 2972 -R .note -R .comment \ 2973 -S vmlinux linux.bin 2974 2975* compress the binary image: 2976 2977 gzip -9 linux.bin 2978 2979* package compressed binary image for U-Boot: 2980 2981 mkimage -A ppc -O linux -T kernel -C gzip \ 2982 -a 0 -e 0 -n "Linux Kernel Image" \ 2983 -d linux.bin.gz uImage 2984 2985 2986The "mkimage" tool can also be used to create ramdisk images for use 2987with U-Boot, either separated from the Linux kernel image, or 2988combined into one file. "mkimage" encapsulates the images with a 64 2989byte header containing information about target architecture, 2990operating system, image type, compression method, entry points, time 2991stamp, CRC32 checksums, etc. 2992 2993"mkimage" can be called in two ways: to verify existing images and 2994print the header information, or to build new images. 2995 2996In the first form (with "-l" option) mkimage lists the information 2997contained in the header of an existing U-Boot image; this includes 2998checksum verification: 2999 3000 tools/mkimage -l image
3001 -l ==> list image header information 3002 3003The second form (with "-d" option) is used to build a U-Boot image 3004from a "data file" which is used as image payload: 3005 3006 tools/mkimage -A arch -O os -T type -C comp -a addr -e ep \ 3007 -n name -d data_file image 3008 -A ==> set architecture to 'arch' 3009 -O ==> set operating system to 'os' 3010 -T ==> set image type to 'type' 3011 -C ==> set compression type 'comp' 3012 -a ==> set load address to 'addr' (hex) 3013 -e ==> set entry point to 'ep' (hex) 3014 -n ==> set image name to 'name' 3015 -d ==> use image data from 'datafile' 3016 3017Right now, all Linux kernels for PowerPC systems use the same load 3018address (0x00000000), but the entry point address depends on the 3019kernel version: 3020 3021- 2.2.x kernels have the entry point at 0x0000000C, 3022- 2.3.x and later kernels have the entry point at 0x00000000. 3023 3024So a typical call to build a U-Boot image would read: 3025 3026 -> tools/mkimage -n '2.4.4 kernel for TQM850L' \ 3027 > -A ppc -O linux -T kernel -C gzip -a 0 -e 0 \ 3028 > -d /opt/elsk/ppc_8xx/usr/src/linux-2.4.4/arch/powerpc/coffboot/vmlinux.gz \ 3029 > examples/uImage.TQM850L 3030 Image Name: 2.4.4 kernel for TQM850L 3031 Created: Wed Jul 19 02:34:59 2000 3032 Image Type: PowerPC Linux Kernel Image (gzip compressed) 3033 Data Size: 335725 Bytes = 327.86 kB = 0.32 MB 3034 Load Address: 0x00000000 3035 Entry Point: 0x00000000 3036 3037To verify the contents of the image (or check for corruption): 3038 3039 -> tools/mkimage -l examples/uImage.TQM850L 3040 Image Name: 2.4.4 kernel for TQM850L 3041 Created: Wed Jul 19 02:34:59 2000 3042 Image Type: PowerPC Linux Kernel Image (gzip compressed) 3043 Data Size: 335725 Bytes = 327.86 kB = 0.32 MB 3044 Load Address: 0x00000000 3045 Entry Point: 0x00000000 3046 3047NOTE: for embedded systems where boot time is critical you can trade 3048speed for memory and install an UNCOMPRESSED image instead: this 3049needs more space in Flash, but boots much faster since it does not 3050need to be uncompressed: 3051 3052 -> gunzip /opt/elsk/ppc_8xx/usr/src/linux-2.4.4/arch/powerpc/coffboot/vmlinux.gz 3053 -> tools/mkimage -n '2.4.4 kernel for TQM850L' \ 3054 > -A ppc -O linux -T kernel -C none -a 0 -e 0 \ 3055 > -d /opt/elsk/ppc_8xx/usr/src/linux-2.4.4/arch/powerpc/coffboot/vmlinux \ 3056 > examples/uImage.TQM850L-uncompressed 3057 Image Name: 2.4.4 kernel for TQM850L 3058 Created: Wed Jul 19 02:34:59 2000 3059 Image Type: PowerPC Linux Kernel Image (uncompressed) 3060 Data Size: 792160 Bytes = 773.59 kB = 0.76 MB 3061 Load Address: 0x00000000 3062 Entry Point: 0x00000000 3063 3064 3065Similar you can build U-Boot images from a 'ramdisk.image.gz' file 3066when your kernel is intended to use an initial ramdisk: 3067 3068 -> tools/mkimage -n 'Simple Ramdisk Image' \ 3069 > -A ppc -O linux -T ramdisk -C gzip \ 3070 > -d /LinuxPPC/images/SIMPLE-ramdisk.image.gz examples/simple-initrd 3071 Image Name: Simple Ramdisk Image 3072 Created: Wed Jan 12 14:01:50 2000 3073 Image Type: PowerPC Linux RAMDisk Image (gzip compressed) 3074 Data Size: 566530 Bytes = 553.25 kB = 0.54 MB 3075 Load Address: 0x00000000 3076 Entry Point: 0x00000000 3077 3078The "dumpimage" tool can be used to disassemble or list the contents of images 3079built by mkimage. See dumpimage's help output (-h) for details. 3080 3081Installing a Linux Image: 3082------------------------- 3083 3084To downloading a U-Boot image over the serial (console) interface, 3085you must convert the image to S-Record format: 3086 3087 objcopy -I binary -O srec examples/image examples/image.srec 3088 3089The 'objcopy' does not understand the information in the U-Boot 3090image header, so the resulting S-Record file will be relative to 3091address 0x00000000. To load it to a given address, you need to 3092specify the target address as 'offset' parameter with the 'loads' 3093command. 3094 3095Example: install the image to address 0x40100000 (which on the 3096TQM8xxL is in the first Flash bank): 3097 3098 => erase 40100000 401FFFFF 3099 3100 .......... done 3101 Erased 8 sectors 3102 3103 => loads 40100000 3104 ## Ready for S-Record download ... 3105 ~>examples/image.srec 3106 1 2 3 4 5 6 7 8 9 10 11 12 13 ... 3107 ... 3108 15989 15990 15991 15992 3109 [file transfer complete] 3110 [connected] 3111 ## Start Addr = 0x00000000 3112 3113 3114You can check the success of the download using the 'iminfo' command; 3115this includes a checksum verification so you can be sure no data 3116corruption happened: 3117 3118 => imi 40100000 3119 3120 ## Checking Image at 40100000 ... 3121 Image Name: 2.2.13 for initrd on TQM850L 3122 Image Type: PowerPC Linux Kernel Image (gzip compressed) 3123 Data Size: 335725 Bytes = 327 kB = 0 MB 3124 Load Address: 00000000 3125 Entry Point: 0000000c 3126 Verifying Checksum ... OK 3127 3128 3129Boot Linux: 3130----------- 3131 3132The "bootm" command is used to boot an application that is stored in 3133memory (RAM or Flash). In case of a Linux kernel image, the contents 3134of the "bootargs" environment variable is passed to the kernel as 3135parameters. You can check and modify this variable using the 3136"printenv" and "setenv" commands: 3137 3138 3139 => printenv bootargs 3140 bootargs=root=/dev/ram 3141 3142 => setenv bootargs root=/dev/nfs rw nfsroot=10.0.0.2:/LinuxPPC nfsaddrs=10.0.0.99:10.0.0.2 3143 3144 => printenv bootargs 3145 bootargs=root=/dev/nfs rw nfsroot=10.0.0.2:/LinuxPPC nfsaddrs=10.0.0.99:10.0.0.2 3146 3147 => bootm 40020000 3148 ## Booting Linux kernel at 40020000 ... 3149 Image Name: 2.2.13 for NFS on TQM850L 3150 Image Type: PowerPC Linux Kernel Image (gzip compressed) 3151 Data Size: 381681 Bytes = 372 kB = 0 MB 3152 Load Address: 00000000 3153 Entry Point: 0000000c 3154 Verifying Checksum ... OK 3155 Uncompressing Kernel Image ... OK 3156 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 3157 Boot arguments: root=/dev/nfs rw nfsroot=10.0.0.2:/LinuxPPC nfsaddrs=10.0.0.99:10.0.0.2 3158 time_init: decrementer frequency = 187500000/60 3159 Calibrating delay loop... 49.77 BogoMIPS 3160 Memory: 15208k available (700k kernel code, 444k data, 32k init) [c0000000,c1000000] 3161 ... 3162 3163If you want to boot a Linux kernel with initial RAM disk, you pass 3164the memory addresses of both the kernel and the initrd image (PPBCOOT 3165format!) to the "bootm" command: 3166 3167 => imi 40100000 40200000 3168 3169 ## Checking Image at 40100000 ... 3170 Image Name: 2.2.13 for initrd on TQM850L 3171 Image Type: PowerPC Linux Kernel Image (gzip compressed) 3172 Data Size: 335725 Bytes = 327 kB = 0 MB 3173 Load Address: 00000000 3174 Entry Point: 0000000c 3175 Verifying Checksum ... OK 3176 3177 ## Checking Image at 40200000 ... 3178 Image Name: Simple Ramdisk Image 3179 Image Type: PowerPC Linux RAMDisk Image (gzip compressed) 3180 Data Size: 566530 Bytes = 553 kB = 0 MB 3181 Load Address: 00000000 3182 Entry Point: 00000000 3183 Verifying Checksum ... OK 3184 3185 => bootm 40100000 40200000 3186 ## Booting Linux kernel at 40100000 ... 3187 Image Name: 2.2.13 for initrd on TQM850L 3188 Image Type: PowerPC Linux Kernel Image (gzip compressed) 3189 Data Size: 335725 Bytes = 327 kB = 0 MB 3190 Load Address: 00000000 3191 Entry Point: 0000000c 3192 Verifying Checksum ... OK 3193 Uncompressing Kernel Image ... OK 3194 ## Loading RAMDisk Image at 40200000 ... 3195 Image Name: Simple Ramdisk Image 3196 Image Type: PowerPC Linux RAMDisk Image (gzip compressed) 3197 Data Size: 566530 Bytes = 553 kB = 0 MB 3198 Load Address: 00000000 3199 Entry Point: 00000000 3200 Verifying Checksum ... OK 3201 Loading Ramdisk ... OK 3202 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 3203 Boot arguments: root=/dev/ram 3204 time_init: decrementer frequency = 187500000/60 3205 Calibrating delay loop... 49.77 BogoMIPS 3206 ... 3207 RAMDISK: Compressed image found at block 0 3208 VFS: Mounted root (ext2 filesystem). 3209 3210 bash# 3211 3212Boot Linux and pass a flat device tree: 3213----------- 3214 3215First, U-Boot must be compiled with the appropriate defines. See the section 3216titled "Linux Kernel Interface" above for a more in depth explanation. The 3217following is an example of how to start a kernel and pass an updated 3218flat device tree: 3219 3220=> print oftaddr 3221oftaddr=0x300000 3222=> print oft 3223oft=oftrees/mpc8540ads.dtb 3224=> tftp $oftaddr $oft 3225Speed: 1000, full duplex 3226Using TSEC0 device 3227TFTP from server 192.168.1.1; our IP address is 192.168.1.101 3228Filename 'oftrees/mpc8540ads.dtb'. 3229Load address: 0x300000 3230Loading: # 3231done 3232Bytes transferred = 4106 (100a hex) 3233=> tftp $loadaddr $bootfile 3234Speed: 1000, full duplex 3235Using TSEC0 device 3236TFTP from server 192.168.1.1; our IP address is 192.168.1.2 3237Filename 'uImage'. 3238Load address: 0x200000 3239Loading:############ 3240done 3241Bytes transferred = 1029407 (fb51f hex) 3242=> print loadaddr 3243loadaddr=200000 3244=> print oftaddr 3245oftaddr=0x300000 3246=> bootm $loadaddr - $oftaddr 3247## Booting image at 00200000 ... 3248 Image Name: Linux-2.6.17-dirty 3249 Image Type: PowerPC Linux Kernel Image (gzip compressed) 3250 Data Size: 1029343 Bytes = 1005.2 kB 3251 Load Address: 00000000 3252 Entry Point: 00000000 3253 Verifying Checksum ... OK 3254 Uncompressing Kernel Image ... OK 3255Booting using flat device tree at 0x300000 3256Using MPC85xx ADS machine description 3257Memory CAM mapping: CAM0=256Mb, CAM1=256Mb, CAM2=0Mb residual: 0Mb 3258[snip] 3259 3260 3261More About U-Boot Image Types: 3262------------------------------ 3263 3264U-Boot supports the following image types: 3265 3266 "Standalone Programs" are directly runnable in the environment 3267 provided by U-Boot; it is expected that (if they behave 3268 well) you can continue to work in U-Boot after return from 3269 the Standalone Program. 3270 "OS Kernel Images" are usually images of some Embedded OS which 3271 will take over control completely. Usually these programs 3272 will install their own set of exception handlers, device 3273 drivers, set up the MMU, etc. - this means, that you cannot 3274 expect to re-enter U-Boot except by resetting the CPU. 3275 "RAMDisk Images" are more or less just data blocks, and their 3276 parameters (address, size) are passed to an OS kernel that is 3277 being started. 3278 "Multi-File Images" contain several images, typically an OS 3279 (Linux) kernel image and one or more data images like 3280 RAMDisks. This construct is useful for instance when you want 3281 to boot over the network using BOOTP etc., where the boot 3282 server provides just a single image file, but you want to get 3283 for instance an OS kernel and a RAMDisk image. 3284 3285 "Multi-File Images" start with a list of image sizes, each 3286 image size (in bytes) specified by an "uint32_t" in network 3287 byte order. This list is terminated by an "(uint32_t)0". 3288 Immediately after the terminating 0 follow the images, one by 3289 one, all aligned on "uint32_t" boundaries (size rounded up to 3290 a multiple of 4 bytes). 3291 3292 "Firmware Images" are binary images containing firmware (like 3293 U-Boot or FPGA images) which usually will be programmed to 3294 flash memory. 3295 3296 "Script files" are command sequences that will be executed by 3297 U-Boot's command interpreter; this feature is especially 3298 useful when you configure U-Boot to use a real shell (hush) 3299 as command interpreter. 3300 3301Booting the Linux zImage: 3302------------------------- 3303 3304On some platforms, it's possible to boot Linux zImage. This is done 3305using the "bootz" command. The syntax of "bootz" command is the same 3306as the syntax of "bootm" command. 3307 3308Note, defining the CONFIG_SUPPORT_RAW_INITRD allows user to supply 3309kernel with raw initrd images. The syntax is slightly different, the 3310address of the initrd must be augmented by it's size, in the following 3311format: "<initrd addres>:<initrd size>". 3312 3313 3314Standalone HOWTO: 3315================= 3316 3317One of the features of U-Boot is that you can dynamically load and 3318run "standalone" applications, which can use some resources of 3319U-Boot like console I/O functions or interrupt services. 3320 3321Two simple examples are included with the sources: 3322 3323"Hello World" Demo: 3324------------------- 3325 3326'examples/hello_world.c' contains a small "Hello World" Demo 3327application; it is automatically compiled when you build U-Boot. 3328It's configured to run at address 0x00040004, so you can play with it 3329like that: 3330 3331 => loads 3332 ## Ready for S-Record download ... 3333 ~>examples/hello_world.srec 3334 1 2 3 4 5 6 7 8 9 10 11 ... 3335 [file transfer complete] 3336 [connected] 3337 ## Start Addr = 0x00040004 3338 3339 => go 40004 Hello World! This is a test. 3340 ## Starting application at 0x00040004 ... 3341 Hello World 3342 argc = 7 3343 argv[0] = "40004" 3344 argv[1] = "Hello" 3345 argv[2] = "World!" 3346 argv[3] = "This" 3347 argv[4] = "is" 3348 argv[5] = "a" 3349 argv[6] = "test." 3350 argv[7] = "<NULL>" 3351 Hit any key to exit ... 3352 3353 ## Application terminated, rc = 0x0 3354 3355Another example, which demonstrates how to register a CPM interrupt 3356handler with the U-Boot code, can be found in 'examples/timer.c'. 3357Here, a CPM timer is set up to generate an interrupt every second. 3358The interrupt service routine is trivial, just printing a '.' 3359character, but this is just a demo program. The application can be 3360controlled by the following keys: 3361 3362 ? - print current values og the CPM Timer registers 3363 b - enable interrupts and start timer 3364 e - stop timer and disable interrupts 3365 q - quit application 3366 3367 => loads 3368 ## Ready for S-Record download ... 3369 ~>examples/timer.srec 3370 1 2 3 4 5 6 7 8 9 10 11 ... 3371 [file transfer complete] 3372 [connected] 3373 ## Start Addr = 0x00040004 3374 3375 => go 40004 3376 ## Starting application at 0x00040004 ... 3377 TIMERS=0xfff00980 3378 Using timer 1 3379 tgcr @ 0xfff00980, tmr @ 0xfff00990, trr @ 0xfff00994, tcr @ 0xfff00998, tcn @ 0xfff0099c, ter @ 0xfff009b0 3380 3381Hit 'b': 3382 [q, b, e, ?] Set interval 1000000 us 3383 Enabling timer 3384Hit '?': 3385 [q, b, e, ?] ........ 3386 tgcr=0x1, tmr=0xff1c, trr=0x3d09, tcr=0x0, tcn=0xef6, ter=0x0 3387Hit '?': 3388 [q, b, e, ?] . 3389 tgcr=0x1, tmr=0xff1c, trr=0x3d09, tcr=0x0, tcn=0x2ad4, ter=0x0 3390Hit '?': 3391 [q, b, e, ?] . 3392 tgcr=0x1, tmr=0xff1c, trr=0x3d09, tcr=0x0, tcn=0x1efc, ter=0x0 3393Hit '?': 3394 [q, b, e, ?] . 3395 tgcr=0x1, tmr=0xff1c, trr=0x3d09, tcr=0x0, tcn=0x169d, ter=0x0 3396Hit 'e': 3397 [q, b, e, ?] ...Stopping timer 3398Hit 'q': 3399 [q, b, e, ?] ## Application terminated, rc = 0x0 3400 3401 3402Minicom warning: 3403================ 3404 3405Over time, many people have reported problems when trying to use the 3406"minicom" terminal emulation program for serial download. I (wd) 3407consider minicom to be broken, and recommend not to use it. Under 3408Unix, I recommend to use C-Kermit for general purpose use (and 3409especially for kermit binary protocol download ("loadb" command), and 3410use "cu" for S-Record download ("loads" command). See 3411https://www.denx.de/wiki/view/DULG/SystemSetup#Section_4.3. 3412for help with kermit. 3413 3414 3415Nevertheless, if you absolutely want to use it try adding this 3416configuration to your "File transfer protocols" section: 3417 3418 Name Program Name U/D FullScr IO-Red. Multi 3419 X kermit /usr/bin/kermit -i -l %l -s Y U Y N N 3420 Y kermit /usr/bin/kermit -i -l %l -r N D Y N N 3421 3422 3423NetBSD Notes: 3424============= 3425 3426Starting at version 0.9.2, U-Boot supports NetBSD both as host 3427(build U-Boot) and target system (boots NetBSD/mpc8xx). 3428 3429Building requires a cross environment; it is known to work on 3430NetBSD/i386 with the cross-powerpc-netbsd-1.3 package (you will also 3431need gmake since the Makefiles are not compatible with BSD make). 3432Note that the cross-powerpc package does not install include files; 3433attempting to build U-Boot will fail because <machine/ansi.h> is 3434missing. This file has to be installed and patched manually: 3435 3436 # cd /usr/pkg/cross/powerpc-netbsd/include 3437 # mkdir powerpc 3438 # ln -s powerpc machine 3439 # cp /usr/src/sys/arch/powerpc/include/ansi.h powerpc/ansi.h 3440 # ${EDIT} powerpc/ansi.h ## must remove __va_list, _BSD_VA_LIST 3441 3442Native builds *don't* work due to incompatibilities between native 3443and U-Boot include files. 3444 3445Booting assumes that (the first part of) the image booted is a 3446stage-2 loader which in turn loads and then invokes the kernel 3447proper. Loader sources will eventually appear in the NetBSD source 3448tree (probably in sys/arc/mpc8xx/stand/u-boot_stage2/); in the 3449meantime, see ftp://ftp.denx.de/pub/u-boot/ppcboot_stage2.tar.gz 3450 3451 3452Implementation Internals: 3453========================= 3454 3455The following is not intended to be a complete description of every 3456implementation detail. However, it should help to understand the 3457inner workings of U-Boot and make it easier to port it to custom 3458hardware. 3459 3460 3461Initial Stack, Global Data: 3462--------------------------- 3463 3464The implementation of U-Boot is complicated by the fact that U-Boot 3465starts running out of ROM (flash memory), usually without access to 3466system RAM (because the memory controller is not initialized yet). 3467This means that we don't have writable Data or BSS segments, and BSS 3468is not initialized as zero. To be able to get a C environment working 3469at all, we have to allocate at least a minimal stack. Implementation 3470options for this are defined and restricted by the CPU used: Some CPU 3471models provide on-chip memory (like the IMMR area on MPC8xx and 3472MPC826x processors), on others (parts of) the data cache can be 3473locked as (mis-) used as memory, etc. 3474 3475 Chris Hallinan posted a good summary of these issues to the 3476 U-Boot mailing list: 3477 3478 Subject: RE: [U-Boot-Users] RE: More On Memory Bank x (nothingness)? 3479 From: "Chris Hallinan" <clh@net1plus.com> 3480 Date: Mon, 10 Feb 2003 16:43:46 -0500 (22:43 MET) 3481 ... 3482 3483 Correct me if I'm wrong, folks, but the way I understand it 3484 is this: Using DCACHE as initial RAM for Stack, etc, does not 3485 require any physical RAM backing up the cache. The cleverness 3486 is that the cache is being used as a temporary supply of 3487 necessary storage before the SDRAM controller is setup. It's 3488 beyond the scope of this list to explain the details, but you 3489 can see how this works by studying the cache architecture and 3490 operation in the architecture and processor-specific manuals. 3491 3492 OCM is On Chip Memory, which I believe the 405GP has 4K. It 3493 is another option for the system designer to use as an 3494 initial stack/RAM area prior to SDRAM being available. Either 3495 option should work for you. Using CS 4 should be fine if your 3496 board designers haven't used it for something that would 3497 cause you grief during the initial boot! It is frequently not 3498 used. 3499 3500 CONFIG_SYS_INIT_RAM_ADDR should be somewhere that won't interfere 3501 with your processor/board/system design. The default value 3502 you will find in any recent u-boot distribution in 3503 walnut.h should work for you. I'd set it to a value larger 3504 than your SDRAM module. If you have a 64MB SDRAM module, set 3505 it above 400_0000. Just make sure your board has no resources 3506 that are supposed to respond to that address! That code in 3507 start.S has been around a while and should work as is when 3508 you get the config right. 3509 3510 -Chris Hallinan 3511 DS4.COM, Inc. 3512 3513It is essential to remember this, since it has some impact on the C 3514code for the initialization procedures: 3515 3516* Initialized global data (data segment) is read-only. Do not attempt 3517 to write it. 3518 3519* Do not use any uninitialized global data (or implicitly initialized 3520 as zero data - BSS segment) at all - this is undefined, initiali- 3521 zation is performed later (when relocating to RAM). 3522 3523* Stack space is very limited. Avoid big data buffers or things like 3524 that. 3525 3526Having only the stack as writable memory limits means we cannot use 3527normal global data to share information between the code. But it 3528turned out that the implementation of U-Boot can be greatly 3529simplified by making a global data structure (gd_t) available to all 3530functions. We could pass a pointer to this data as argument to _all_ 3531functions, but this would bloat the code. Instead we use a feature of 3532the GCC compiler (Global Register Variables) to share the data: we 3533place a pointer (gd) to the global data into a register which we 3534reserve for this purpose. 3535 3536When choosing a register for such a purpose we are restricted by the 3537relevant (E)ABI specifications for the current architecture, and by 3538GCC's implementation. 3539 3540For PowerPC, the following registers have specific use: 3541 R1: stack pointer 3542 R2: reserved for system use 3543 R3-R4: parameter passing and return values 3544 R5-R10: parameter passing 3545 R13: small data area pointer 3546 R30: GOT pointer 3547 R31: frame pointer 3548 3549 (U-Boot also uses R12 as internal GOT pointer. r12 3550 is a volatile register so r12 needs to be reset when 3551 going back and forth between asm and C) 3552 3553 ==> U-Boot will use R2 to hold a pointer to the global data 3554 3555 Note: on PPC, we could use a static initializer (since the 3556 address of the global data structure is known at compile time), 3557 but it turned out that reserving a register results in somewhat 3558 smaller code - although the code savings are not that big (on 3559 average for all boards 752 bytes for the whole U-Boot image, 3560 624 text + 127 data). 3561 3562On ARM, the following registers are used: 3563 3564 R0: function argument word/integer result 3565 R1-R3: function argument word 3566 R9: platform specific 3567 R10: stack limit (used only if stack checking is enabled) 3568 R11: argument (frame) pointer 3569 R12: temporary workspace 3570 R13: stack pointer 3571 R14: link register 3572 R15: program counter 3573 3574 ==> U-Boot will use R9 to hold a pointer to the global data 3575 3576 Note: on ARM, only R_ARM_RELATIVE relocations are supported. 3577 3578On Nios II, the ABI is documented here: 3579 https://www.altera.com/literature/hb/nios2/n2cpu_nii51016.pdf 3580 3581 ==> U-Boot will use gp to hold a pointer to the global data 3582 3583 Note: on Nios II, we give "-G0" option to gcc and don't use gp 3584 to access small data sections, so gp is free. 3585 3586On NDS32, the following registers are used: 3587 3588 R0-R1: argument/return 3589 R2-R5: argument 3590 R15: temporary register for assembler 3591 R16: trampoline register 3592 R28: frame pointer (FP) 3593 R29: global pointer (GP) 3594 R30: link register (LP) 3595 R31: stack pointer (SP) 3596 PC: program counter (PC) 3597 3598 ==> U-Boot will use R10 to hold a pointer to the global data 3599 3600NOTE: DECLARE_GLOBAL_DATA_PTR must be used with file-global scope, 3601or current versions of GCC may "optimize" the code too much. 3602 3603On RISC-V, the following registers are used: 3604 3605 x0: hard-wired zero (zero) 3606 x1: return address (ra) 3607 x2: stack pointer (sp) 3608 x3: global pointer (gp) 3609 x4: thread pointer (tp) 3610 x5: link register (t0) 3611 x8: frame pointer (fp) 3612 x10-x11: arguments/return values (a0-1) 3613 x12-x17: arguments (a2-7) 3614 x28-31: temporaries (t3-6) 3615 pc: program counter (pc) 3616 3617 ==> U-Boot will use gp to hold a pointer to the global data 3618 3619Memory Management: 3620------------------ 3621 3622U-Boot runs in system state and uses physical addresses, i.e. the 3623MMU is not used either for address mapping nor for memory protection. 3624 3625The available memory is mapped to fixed addresses using the memory 3626controller. In this process, a contiguous block is formed for each 3627memory type (Flash, SDRAM, SRAM), even when it consists of several 3628physical memory banks. 3629 3630U-Boot is installed in the first 128 kB of the first Flash bank (on 3631TQM8xxL modules this is the range 0x40000000 ... 0x4001FFFF). After 3632booting and sizing and initializing DRAM, the code relocates itself 3633to the upper end of DRAM. Immediately below the U-Boot code some 3634memory is reserved for use by malloc() [see CONFIG_SYS_MALLOC_LEN 3635configuration setting]. Below that, a structure with global Board 3636Info data is placed, followed by the stack (growing downward). 3637 3638Additionally, some exception handler code is copied to the low 8 kB 3639of DRAM (0x00000000 ... 0x00001FFF). 3640 3641So a typical memory configuration with 16 MB of DRAM could look like 3642this: 3643 3644 0x0000 0000 Exception Vector code 3645 : 3646 0x0000 1FFF 3647 0x0000 2000 Free for Application Use 3648 : 3649 : 3650 3651 : 3652 : 3653 0x00FB FF20 Monitor Stack (Growing downward) 3654 0x00FB FFAC Board Info Data and permanent copy of global data 3655 0x00FC 0000 Malloc Arena 3656 : 3657 0x00FD FFFF 3658 0x00FE 0000 RAM Copy of Monitor Code 3659 ... eventually: LCD or video framebuffer 3660 ... eventually: pRAM (Protected RAM - unchanged by reset) 3661 0x00FF FFFF [End of RAM] 3662 3663 3664System Initialization: 3665---------------------- 3666 3667In the reset configuration, U-Boot starts at the reset entry point 3668(on most PowerPC systems at address 0x00000100). Because of the reset 3669configuration for CS0# this is a mirror of the on board Flash memory. 3670To be able to re-map memory U-Boot then jumps to its link address. 3671To be able to implement the initialization code in C, a (small!) 3672initial stack is set up in the internal Dual Ported RAM (in case CPUs 3673which provide such a feature like), or in a locked part of the data 3674cache. After that, U-Boot initializes the CPU core, the caches and 3675the SIU. 3676 3677Next, all (potentially) available memory banks are mapped using a 3678preliminary mapping. For example, we put them on 512 MB boundaries 3679(multiples of 0x20000000: SDRAM on 0x00000000 and 0x20000000, Flash 3680on 0x40000000 and 0x60000000, SRAM on 0x80000000). Then UPM A is 3681programmed for SDRAM access. Using the temporary configuration, a 3682simple memory test is run that determines the size of the SDRAM 3683banks. 3684 3685When there is more than one SDRAM bank, and the banks are of 3686different size, the largest is mapped first. For equal size, the first 3687bank (CS2#) is mapped first. The first mapping is always for address 36880x00000000, with any additional banks following immediately to create 3689contiguous memory starting from 0. 3690 3691Then, the monitor installs itself at the upper end of the SDRAM area 3692and allocates memory for use by malloc() and for the global Board 3693Info data; also, the exception vector code is copied to the low RAM 3694pages, and the final stack is set up. 3695 3696Only after this relocation will you have a "normal" C environment; 3697until that you are restricted in several ways, mostly because you are 3698running from ROM, and because the code will have to be relocated to a 3699new address in RAM. 3700 3701 3702U-Boot Porting Guide: 3703---------------------- 3704 3705[Based on messages by Jerry Van Baren in the U-Boot-Users mailing 3706list, October 2002] 3707 3708 3709int main(int argc, char *argv[]) 3710{ 3711 sighandler_t no_more_time; 3712 3713 signal(SIGALRM, no_more_time); 3714 alarm(PROJECT_DEADLINE - toSec (3 * WEEK)); 3715 3716 if (available_money > available_manpower) { 3717 Pay consultant to port U-Boot; 3718 return 0; 3719 } 3720 3721 Download latest U-Boot source; 3722 3723 Subscribe to u-boot mailing list; 3724 3725 if (clueless) 3726 email("Hi, I am new to U-Boot, how do I get started?"); 3727 3728 while (learning) { 3729 Read the README file in the top level directory; 3730 Read https://www.denx.de/wiki/bin/view/DULG/Manual; 3731 Read applicable doc/README.*; 3732 Read the source, Luke; 3733 /* find . -name "*.[chS]" | xargs grep -i <keyword> */ 3734 } 3735 3736 if (available_money > toLocalCurrency ($2500)) 3737 Buy a BDI3000; 3738 else 3739 Add a lot of aggravation and time; 3740 3741 if (a similar board exists) { /* hopefully... */ 3742 cp -a board/<similar> board/<myboard> 3743 cp include/configs/<similar>.h include/configs/<myboard>.h 3744 } else { 3745 Create your own board support subdirectory; 3746 Create your own board include/configs/<myboard>.h file; 3747 } 3748 Edit new board/<myboard> files 3749 Edit new include/configs/<myboard>.h 3750 3751 while (!accepted) { 3752 while (!running) { 3753 do { 3754 Add / modify source code; 3755 } until (compiles); 3756 Debug; 3757 if (clueless) 3758 email("Hi, I am having problems..."); 3759 } 3760 Send patch file to the U-Boot email list; 3761 if (reasonable critiques) 3762 Incorporate improvements from email list code review; 3763 else 3764 Defend code as written; 3765 } 3766 3767 return 0; 3768} 3769 3770void no_more_time (int sig) 3771{ 3772 hire_a_guru(); 3773} 3774 3775 3776Coding Standards: 3777----------------- 3778 3779All contributions to U-Boot should conform to the Linux kernel 3780coding style; see the kernel coding style guide at 3781https://www.kernel.org/doc/html/latest/process/coding-style.html, and the 3782script "scripts/Lindent" in your Linux kernel source directory. 3783 3784Source files originating from a different project (for example the 3785MTD subsystem) are generally exempt from these guidelines and are not 3786reformatted to ease subsequent migration to newer versions of those 3787sources. 3788 3789Please note that U-Boot is implemented in C (and to some small parts in 3790Assembler); no C++ is used, so please do not use C++ style comments (//) 3791in your code. 3792 3793Please also stick to the following formatting rules: 3794- remove any trailing white space 3795- use TAB characters for indentation and vertical alignment, not spaces 3796- make sure NOT to use DOS '\r\n' line feeds 3797- do not add more than 2 consecutive empty lines to source files 3798- do not add trailing empty lines to source files 3799 3800Submissions which do not conform to the standards may be returned 3801with a request to reformat the changes. 3802 3803 3804Submitting Patches: 3805------------------- 3806 3807Since the number of patches for U-Boot is growing, we need to 3808establish some rules. Submissions which do not conform to these rules 3809may be rejected, even when they contain important and valuable stuff. 3810 3811Please see https://www.denx.de/wiki/U-Boot/Patches for details. 3812 3813Patches shall be sent to the u-boot mailing list <u-boot@lists.denx.de>; 3814see https://lists.denx.de/listinfo/u-boot 3815 3816When you send a patch, please include the following information with 3817it: 3818 3819* For bug fixes: a description of the bug and how your patch fixes 3820 this bug. Please try to include a way of demonstrating that the 3821 patch actually fixes something. 3822 3823* For new features: a description of the feature and your 3824 implementation. 3825 3826* For major contributions, add a MAINTAINERS file with your 3827 information and associated file and directory references. 3828 3829* When you add support for a new board, don't forget to add a 3830 maintainer e-mail address to the boards.cfg file, too. 3831 3832* If your patch adds new configuration options, don't forget to 3833 document these in the README file. 3834 3835* The patch itself. If you are using git (which is *strongly* 3836 recommended) you can easily generate the patch using the 3837 "git format-patch". If you then use "git send-email" to send it to 3838 the U-Boot mailing list, you will avoid most of the common problems 3839 with some other mail clients. 3840 3841 If you cannot use git, use "diff -purN OLD NEW". If your version of 3842 diff does not support these options, then get the latest version of 3843 GNU diff. 3844 3845 The current directory when running this command shall be the parent 3846 directory of the U-Boot source tree (i. e. please make sure that 3847 your patch includes sufficient directory information for the 3848 affected files). 3849 3850 We prefer patches as plain text. MIME attachments are discouraged, 3851 and compressed attachments must not be used. 3852 3853* If one logical set of modifications affects or creates several 3854 files, all these changes shall be submitted in a SINGLE patch file. 3855 3856* Changesets that contain different, unrelated modifications shall be 3857 submitted as SEPARATE patches, one patch per changeset. 3858 3859 3860Notes: 3861 3862* Before sending the patch, run the buildman script on your patched 3863 source tree and make sure that no errors or warnings are reported 3864 for any of the boards. 3865 3866* Keep your modifications to the necessary minimum: A patch 3867 containing several unrelated changes or arbitrary reformats will be 3868 returned with a request to re-formatting / split it. 3869 3870* If you modify existing code, make sure that your new code does not 3871 add to the memory footprint of the code ;-) Small is beautiful! 3872 When adding new features, these should compile conditionally only 3873 (using #ifdef), and the resulting code with the new feature 3874 disabled must not need more memory than the old code without your 3875 modification. 3876 3877* Remember that there is a size limit of 100 kB per message on the 3878 u-boot mailing list. Bigger patches will be moderated. If they are 3879 reasonable and not too big, they will be acknowledged. But patches 3880 bigger than the size limit should be avoided. 3881