uboot/include/fdtdec.h
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   1/* SPDX-License-Identifier: GPL-2.0+ */
   2/*
   3 * Copyright (c) 2011 The Chromium OS Authors.
   4 */
   5
   6#ifndef __fdtdec_h
   7#define __fdtdec_h
   8
   9/*
  10 * This file contains convenience functions for decoding useful and
  11 * enlightening information from FDTs. It is intended to be used by device
  12 * drivers and board-specific code within U-Boot. It aims to reduce the
  13 * amount of FDT munging required within U-Boot itself, so that driver code
  14 * changes to support FDT are minimized.
  15 */
  16
  17#include <linux/libfdt.h>
  18#include <pci.h>
  19
  20/*
  21 * A typedef for a physical address. Note that fdt data is always big
  22 * endian even on a litle endian machine.
  23 */
  24typedef phys_addr_t fdt_addr_t;
  25typedef phys_size_t fdt_size_t;
  26
  27#define FDT_ADDR_T_NONE (-1U)
  28#define FDT_SIZE_T_NONE (-1U)
  29
  30#ifdef CONFIG_PHYS_64BIT
  31#define fdt_addr_to_cpu(reg) be64_to_cpu(reg)
  32#define fdt_size_to_cpu(reg) be64_to_cpu(reg)
  33#define cpu_to_fdt_addr(reg) cpu_to_be64(reg)
  34#define cpu_to_fdt_size(reg) cpu_to_be64(reg)
  35typedef fdt64_t fdt_val_t;
  36#else
  37#define fdt_addr_to_cpu(reg) be32_to_cpu(reg)
  38#define fdt_size_to_cpu(reg) be32_to_cpu(reg)
  39#define cpu_to_fdt_addr(reg) cpu_to_be32(reg)
  40#define cpu_to_fdt_size(reg) cpu_to_be32(reg)
  41typedef fdt32_t fdt_val_t;
  42#endif
  43
  44/* Information obtained about memory from the FDT */
  45struct fdt_memory {
  46        fdt_addr_t start;
  47        fdt_addr_t end;
  48};
  49
  50struct bd_info;
  51
  52#ifdef CONFIG_SPL_BUILD
  53#define SPL_BUILD       1
  54#else
  55#define SPL_BUILD       0
  56#endif
  57
  58/*
  59 * Information about a resource. start is the first address of the resource
  60 * and end is the last address (inclusive). The length of the resource will
  61 * be equal to: end - start + 1.
  62 */
  63struct fdt_resource {
  64        fdt_addr_t start;
  65        fdt_addr_t end;
  66};
  67
  68enum fdt_pci_space {
  69        FDT_PCI_SPACE_CONFIG = 0,
  70        FDT_PCI_SPACE_IO = 0x01000000,
  71        FDT_PCI_SPACE_MEM32 = 0x02000000,
  72        FDT_PCI_SPACE_MEM64 = 0x03000000,
  73        FDT_PCI_SPACE_MEM32_PREF = 0x42000000,
  74        FDT_PCI_SPACE_MEM64_PREF = 0x43000000,
  75};
  76
  77#define FDT_PCI_ADDR_CELLS      3
  78#define FDT_PCI_SIZE_CELLS      2
  79#define FDT_PCI_REG_SIZE        \
  80        ((FDT_PCI_ADDR_CELLS + FDT_PCI_SIZE_CELLS) * sizeof(u32))
  81
  82/*
  83 * The Open Firmware spec defines PCI physical address as follows:
  84 *
  85 *          bits# 31 .... 24 23 .... 16 15 .... 08 07 .... 00
  86 *
  87 * phys.hi  cell:  npt000ss   bbbbbbbb   dddddfff   rrrrrrrr
  88 * phys.mid cell:  hhhhhhhh   hhhhhhhh   hhhhhhhh   hhhhhhhh
  89 * phys.lo  cell:  llllllll   llllllll   llllllll   llllllll
  90 *
  91 * where:
  92 *
  93 * n:        is 0 if the address is relocatable, 1 otherwise
  94 * p:        is 1 if addressable region is prefetchable, 0 otherwise
  95 * t:        is 1 if the address is aliased (for non-relocatable I/O) below 1MB
  96 *           (for Memory), or below 64KB (for relocatable I/O)
  97 * ss:       is the space code, denoting the address space
  98 * bbbbbbbb: is the 8-bit Bus Number
  99 * ddddd:    is the 5-bit Device Number
 100 * fff:      is the 3-bit Function Number
 101 * rrrrrrrr: is the 8-bit Register Number
 102 * hhhhhhhh: is a 32-bit unsigned number
 103 * llllllll: is a 32-bit unsigned number
 104 */
 105struct fdt_pci_addr {
 106        u32     phys_hi;
 107        u32     phys_mid;
 108        u32     phys_lo;
 109};
 110
 111extern u8 __dtb_dt_begin[];     /* embedded device tree blob */
 112extern u8 __dtb_dt_spl_begin[]; /* embedded device tree blob for SPL/TPL */
 113
 114/**
 115 * Compute the size of a resource.
 116 *
 117 * @param res   the resource to operate on
 118 * @return the size of the resource
 119 */
 120static inline fdt_size_t fdt_resource_size(const struct fdt_resource *res)
 121{
 122        return res->end - res->start + 1;
 123}
 124
 125/**
 126 * Compat types that we know about and for which we might have drivers.
 127 * Each is named COMPAT_<dir>_<filename> where <dir> is the directory
 128 * within drivers.
 129 */
 130enum fdt_compat_id {
 131        COMPAT_UNKNOWN,
 132        COMPAT_NVIDIA_TEGRA20_EMC,      /* Tegra20 memory controller */
 133        COMPAT_NVIDIA_TEGRA20_EMC_TABLE, /* Tegra20 memory timing table */
 134        COMPAT_NVIDIA_TEGRA20_NAND,     /* Tegra2 NAND controller */
 135        COMPAT_NVIDIA_TEGRA124_XUSB_PADCTL,
 136                                        /* Tegra124 XUSB pad controller */
 137        COMPAT_NVIDIA_TEGRA210_XUSB_PADCTL,
 138                                        /* Tegra210 XUSB pad controller */
 139        COMPAT_SAMSUNG_EXYNOS_USB_PHY,  /* Exynos phy controller for usb2.0 */
 140        COMPAT_SAMSUNG_EXYNOS5_USB3_PHY,/* Exynos phy controller for usb3.0 */
 141        COMPAT_SAMSUNG_EXYNOS_TMU,      /* Exynos TMU */
 142        COMPAT_SAMSUNG_EXYNOS_MIPI_DSI, /* Exynos mipi dsi */
 143        COMPAT_SAMSUNG_EXYNOS_DWMMC,    /* Exynos DWMMC controller */
 144        COMPAT_GENERIC_SPI_FLASH,       /* Generic SPI Flash chip */
 145        COMPAT_SAMSUNG_EXYNOS_SYSMMU,   /* Exynos sysmmu */
 146        COMPAT_INTEL_MICROCODE,         /* Intel microcode update */
 147        COMPAT_INTEL_QRK_MRC,           /* Intel Quark MRC */
 148        COMPAT_ALTERA_SOCFPGA_DWMAC,    /* SoCFPGA Ethernet controller */
 149        COMPAT_ALTERA_SOCFPGA_DWMMC,    /* SoCFPGA DWMMC controller */
 150        COMPAT_ALTERA_SOCFPGA_DWC2USB,  /* SoCFPGA DWC2 USB controller */
 151        COMPAT_INTEL_BAYTRAIL_FSP,      /* Intel Bay Trail FSP */
 152        COMPAT_INTEL_BAYTRAIL_FSP_MDP,  /* Intel FSP memory-down params */
 153        COMPAT_INTEL_IVYBRIDGE_FSP,     /* Intel Ivy Bridge FSP */
 154        COMPAT_SUNXI_NAND,              /* SUNXI NAND controller */
 155        COMPAT_ALTERA_SOCFPGA_CLK,      /* SoCFPGA Clock initialization */
 156        COMPAT_ALTERA_SOCFPGA_PINCTRL_SINGLE,   /* SoCFPGA pinctrl-single */
 157        COMPAT_ALTERA_SOCFPGA_H2F_BRG,          /* SoCFPGA hps2fpga bridge */
 158        COMPAT_ALTERA_SOCFPGA_LWH2F_BRG,        /* SoCFPGA lwhps2fpga bridge */
 159        COMPAT_ALTERA_SOCFPGA_F2H_BRG,          /* SoCFPGA fpga2hps bridge */
 160        COMPAT_ALTERA_SOCFPGA_F2SDR0,           /* SoCFPGA fpga2SDRAM0 bridge */
 161        COMPAT_ALTERA_SOCFPGA_F2SDR1,           /* SoCFPGA fpga2SDRAM1 bridge */
 162        COMPAT_ALTERA_SOCFPGA_F2SDR2,           /* SoCFPGA fpga2SDRAM2 bridge */
 163        COMPAT_ALTERA_SOCFPGA_FPGA0,            /* SOCFPGA FPGA manager */
 164        COMPAT_ALTERA_SOCFPGA_NOC,              /* SOCFPGA Arria 10 NOC */
 165        COMPAT_ALTERA_SOCFPGA_CLK_INIT,         /* SOCFPGA Arria 10 clk init */
 166
 167        COMPAT_COUNT,
 168};
 169
 170#define MAX_PHANDLE_ARGS 16
 171struct fdtdec_phandle_args {
 172        int node;
 173        int args_count;
 174        uint32_t args[MAX_PHANDLE_ARGS];
 175};
 176
 177/**
 178 * fdtdec_parse_phandle_with_args() - Find a node pointed by phandle in a list
 179 *
 180 * This function is useful to parse lists of phandles and their arguments.
 181 *
 182 * Example:
 183 *
 184 * phandle1: node1 {
 185 *      #list-cells = <2>;
 186 * }
 187 *
 188 * phandle2: node2 {
 189 *      #list-cells = <1>;
 190 * }
 191 *
 192 * node3 {
 193 *      list = <&phandle1 1 2 &phandle2 3>;
 194 * }
 195 *
 196 * To get a device_node of the `node2' node you may call this:
 197 * fdtdec_parse_phandle_with_args(blob, node3, "list", "#list-cells", 0, 1,
 198 *                                &args);
 199 *
 200 * (This function is a modified version of __of_parse_phandle_with_args() from
 201 * Linux 3.18)
 202 *
 203 * @blob:       Pointer to device tree
 204 * @src_node:   Offset of device tree node containing a list
 205 * @list_name:  property name that contains a list
 206 * @cells_name: property name that specifies the phandles' arguments count,
 207 *              or NULL to use @cells_count
 208 * @cells_count: Cell count to use if @cells_name is NULL
 209 * @index:      index of a phandle to parse out
 210 * @out_args:   optional pointer to output arguments structure (will be filled)
 211 * @return 0 on success (with @out_args filled out if not NULL), -ENOENT if
 212 *      @list_name does not exist, a phandle was not found, @cells_name
 213 *      could not be found, the arguments were truncated or there were too
 214 *      many arguments.
 215 *
 216 */
 217int fdtdec_parse_phandle_with_args(const void *blob, int src_node,
 218                                   const char *list_name,
 219                                   const char *cells_name,
 220                                   int cell_count, int index,
 221                                   struct fdtdec_phandle_args *out_args);
 222
 223/**
 224 * Find the next numbered alias for a peripheral. This is used to enumerate
 225 * all the peripherals of a certain type.
 226 *
 227 * Do the first call with *upto = 0. Assuming /aliases/<name>0 exists then
 228 * this function will return a pointer to the node the alias points to, and
 229 * then update *upto to 1. Next time you call this function, the next node
 230 * will be returned.
 231 *
 232 * All nodes returned will match the compatible ID, as it is assumed that
 233 * all peripherals use the same driver.
 234 *
 235 * @param blob          FDT blob to use
 236 * @param name          Root name of alias to search for
 237 * @param id            Compatible ID to look for
 238 * @return offset of next compatible node, or -FDT_ERR_NOTFOUND if no more
 239 */
 240int fdtdec_next_alias(const void *blob, const char *name,
 241                enum fdt_compat_id id, int *upto);
 242
 243/**
 244 * Find the compatible ID for a given node.
 245 *
 246 * Generally each node has at least one compatible string attached to it.
 247 * This function looks through our list of known compatible strings and
 248 * returns the corresponding ID which matches the compatible string.
 249 *
 250 * @param blob          FDT blob to use
 251 * @param node          Node containing compatible string to find
 252 * @return compatible ID, or COMPAT_UNKNOWN if we cannot find a match
 253 */
 254enum fdt_compat_id fdtdec_lookup(const void *blob, int node);
 255
 256/**
 257 * Find the next compatible node for a peripheral.
 258 *
 259 * Do the first call with node = 0. This function will return a pointer to
 260 * the next compatible node. Next time you call this function, pass the
 261 * value returned, and the next node will be provided.
 262 *
 263 * @param blob          FDT blob to use
 264 * @param node          Start node for search
 265 * @param id            Compatible ID to look for (enum fdt_compat_id)
 266 * @return offset of next compatible node, or -FDT_ERR_NOTFOUND if no more
 267 */
 268int fdtdec_next_compatible(const void *blob, int node,
 269                enum fdt_compat_id id);
 270
 271/**
 272 * Find the next compatible subnode for a peripheral.
 273 *
 274 * Do the first call with node set to the parent and depth = 0. This
 275 * function will return the offset of the next compatible node. Next time
 276 * you call this function, pass the node value returned last time, with
 277 * depth unchanged, and the next node will be provided.
 278 *
 279 * @param blob          FDT blob to use
 280 * @param node          Start node for search
 281 * @param id            Compatible ID to look for (enum fdt_compat_id)
 282 * @param depthp        Current depth (set to 0 before first call)
 283 * @return offset of next compatible node, or -FDT_ERR_NOTFOUND if no more
 284 */
 285int fdtdec_next_compatible_subnode(const void *blob, int node,
 286                enum fdt_compat_id id, int *depthp);
 287
 288/*
 289 * Look up an address property in a node and return the parsed address, and
 290 * optionally the parsed size.
 291 *
 292 * This variant assumes a known and fixed number of cells are used to
 293 * represent the address and size.
 294 *
 295 * You probably don't want to use this function directly except to parse
 296 * non-standard properties, and never to parse the "reg" property. Instead,
 297 * use one of the "auto" variants below, which automatically honor the
 298 * #address-cells and #size-cells properties in the parent node.
 299 *
 300 * @param blob  FDT blob
 301 * @param node  node to examine
 302 * @param prop_name     name of property to find
 303 * @param index which address to retrieve from a list of addresses. Often 0.
 304 * @param na    the number of cells used to represent an address
 305 * @param ns    the number of cells used to represent a size
 306 * @param sizep a pointer to store the size into. Use NULL if not required
 307 * @param translate     Indicates whether to translate the returned value
 308 *                      using the parent node's ranges property.
 309 * @return address, if found, or FDT_ADDR_T_NONE if not
 310 */
 311fdt_addr_t fdtdec_get_addr_size_fixed(const void *blob, int node,
 312                const char *prop_name, int index, int na, int ns,
 313                fdt_size_t *sizep, bool translate);
 314
 315/*
 316 * Look up an address property in a node and return the parsed address, and
 317 * optionally the parsed size.
 318 *
 319 * This variant automatically determines the number of cells used to represent
 320 * the address and size by parsing the provided parent node's #address-cells
 321 * and #size-cells properties.
 322 *
 323 * @param blob  FDT blob
 324 * @param parent        parent node of @node
 325 * @param node  node to examine
 326 * @param prop_name     name of property to find
 327 * @param index which address to retrieve from a list of addresses. Often 0.
 328 * @param sizep a pointer to store the size into. Use NULL if not required
 329 * @param translate     Indicates whether to translate the returned value
 330 *                      using the parent node's ranges property.
 331 * @return address, if found, or FDT_ADDR_T_NONE if not
 332 */
 333fdt_addr_t fdtdec_get_addr_size_auto_parent(const void *blob, int parent,
 334                int node, const char *prop_name, int index, fdt_size_t *sizep,
 335                bool translate);
 336
 337/*
 338 * Look up an address property in a node and return the parsed address, and
 339 * optionally the parsed size.
 340 *
 341 * This variant automatically determines the number of cells used to represent
 342 * the address and size by parsing the parent node's #address-cells
 343 * and #size-cells properties. The parent node is automatically found.
 344 *
 345 * The automatic parent lookup implemented by this function is slow.
 346 * Consequently, fdtdec_get_addr_size_auto_parent() should be used where
 347 * possible.
 348 *
 349 * @param blob  FDT blob
 350 * @param parent        parent node of @node
 351 * @param node  node to examine
 352 * @param prop_name     name of property to find
 353 * @param index which address to retrieve from a list of addresses. Often 0.
 354 * @param sizep a pointer to store the size into. Use NULL if not required
 355 * @param translate     Indicates whether to translate the returned value
 356 *                      using the parent node's ranges property.
 357 * @return address, if found, or FDT_ADDR_T_NONE if not
 358 */
 359fdt_addr_t fdtdec_get_addr_size_auto_noparent(const void *blob, int node,
 360                const char *prop_name, int index, fdt_size_t *sizep,
 361                bool translate);
 362
 363/*
 364 * Look up an address property in a node and return the parsed address.
 365 *
 366 * This variant hard-codes the number of cells used to represent the address
 367 * and size based on sizeof(fdt_addr_t) and sizeof(fdt_size_t). It also
 368 * always returns the first address value in the property (index 0).
 369 *
 370 * Use of this function is not recommended due to the hard-coding of cell
 371 * counts. There is no programmatic validation that these hard-coded values
 372 * actually match the device tree content in any way at all. This assumption
 373 * can be satisfied by manually ensuring CONFIG_PHYS_64BIT is appropriately
 374 * set in the U-Boot build and exercising strict control over DT content to
 375 * ensure use of matching #address-cells/#size-cells properties. However, this
 376 * approach is error-prone; those familiar with DT will not expect the
 377 * assumption to exist, and could easily invalidate it. If the assumption is
 378 * invalidated, this function will not report the issue, and debugging will
 379 * be required. Instead, use fdtdec_get_addr_size_auto_parent().
 380 *
 381 * @param blob  FDT blob
 382 * @param node  node to examine
 383 * @param prop_name     name of property to find
 384 * @return address, if found, or FDT_ADDR_T_NONE if not
 385 */
 386fdt_addr_t fdtdec_get_addr(const void *blob, int node,
 387                const char *prop_name);
 388
 389/*
 390 * Look up an address property in a node and return the parsed address, and
 391 * optionally the parsed size.
 392 *
 393 * This variant hard-codes the number of cells used to represent the address
 394 * and size based on sizeof(fdt_addr_t) and sizeof(fdt_size_t). It also
 395 * always returns the first address value in the property (index 0).
 396 *
 397 * Use of this function is not recommended due to the hard-coding of cell
 398 * counts. There is no programmatic validation that these hard-coded values
 399 * actually match the device tree content in any way at all. This assumption
 400 * can be satisfied by manually ensuring CONFIG_PHYS_64BIT is appropriately
 401 * set in the U-Boot build and exercising strict control over DT content to
 402 * ensure use of matching #address-cells/#size-cells properties. However, this
 403 * approach is error-prone; those familiar with DT will not expect the
 404 * assumption to exist, and could easily invalidate it. If the assumption is
 405 * invalidated, this function will not report the issue, and debugging will
 406 * be required. Instead, use fdtdec_get_addr_size_auto_parent().
 407 *
 408 * @param blob  FDT blob
 409 * @param node  node to examine
 410 * @param prop_name     name of property to find
 411 * @param sizep a pointer to store the size into. Use NULL if not required
 412 * @return address, if found, or FDT_ADDR_T_NONE if not
 413 */
 414fdt_addr_t fdtdec_get_addr_size(const void *blob, int node,
 415                const char *prop_name, fdt_size_t *sizep);
 416
 417/**
 418 * Look at the compatible property of a device node that represents a PCI
 419 * device and extract pci vendor id and device id from it.
 420 *
 421 * @param blob          FDT blob
 422 * @param node          node to examine
 423 * @param vendor        vendor id of the pci device
 424 * @param device        device id of the pci device
 425 * @return 0 if ok, negative on error
 426 */
 427int fdtdec_get_pci_vendev(const void *blob, int node,
 428                u16 *vendor, u16 *device);
 429
 430/**
 431 * Look at the pci address of a device node that represents a PCI device
 432 * and return base address of the pci device's registers.
 433 *
 434 * @param dev           device to examine
 435 * @param addr          pci address in the form of fdt_pci_addr
 436 * @param bar           returns base address of the pci device's registers
 437 * @return 0 if ok, negative on error
 438 */
 439int fdtdec_get_pci_bar32(const struct udevice *dev, struct fdt_pci_addr *addr,
 440                         u32 *bar);
 441
 442/**
 443 * Look at the bus range property of a device node and return the pci bus
 444 * range for this node.
 445 * The property must hold one fdt_pci_addr with a length.
 446 * @param blob          FDT blob
 447 * @param node          node to examine
 448 * @param res           the resource structure to return the bus range
 449 * @return 0 if ok, negative on error
 450 */
 451
 452int fdtdec_get_pci_bus_range(const void *blob, int node,
 453                             struct fdt_resource *res);
 454
 455/**
 456 * Look up a 32-bit integer property in a node and return it. The property
 457 * must have at least 4 bytes of data. The value of the first cell is
 458 * returned.
 459 *
 460 * @param blob  FDT blob
 461 * @param node  node to examine
 462 * @param prop_name     name of property to find
 463 * @param default_val   default value to return if the property is not found
 464 * @return integer value, if found, or default_val if not
 465 */
 466s32 fdtdec_get_int(const void *blob, int node, const char *prop_name,
 467                s32 default_val);
 468
 469/**
 470 * Unsigned version of fdtdec_get_int. The property must have at least
 471 * 4 bytes of data. The value of the first cell is returned.
 472 *
 473 * @param blob  FDT blob
 474 * @param node  node to examine
 475 * @param prop_name     name of property to find
 476 * @param default_val   default value to return if the property is not found
 477 * @return unsigned integer value, if found, or default_val if not
 478 */
 479unsigned int fdtdec_get_uint(const void *blob, int node, const char *prop_name,
 480                        unsigned int default_val);
 481
 482/**
 483 * Get a variable-sized number from a property
 484 *
 485 * This reads a number from one or more cells.
 486 *
 487 * @param ptr   Pointer to property
 488 * @param cells Number of cells containing the number
 489 * @return the value in the cells
 490 */
 491u64 fdtdec_get_number(const fdt32_t *ptr, unsigned int cells);
 492
 493/**
 494 * Look up a 64-bit integer property in a node and return it. The property
 495 * must have at least 8 bytes of data (2 cells). The first two cells are
 496 * concatenated to form a 8 bytes value, where the first cell is top half and
 497 * the second cell is bottom half.
 498 *
 499 * @param blob  FDT blob
 500 * @param node  node to examine
 501 * @param prop_name     name of property to find
 502 * @param default_val   default value to return if the property is not found
 503 * @return integer value, if found, or default_val if not
 504 */
 505uint64_t fdtdec_get_uint64(const void *blob, int node, const char *prop_name,
 506                uint64_t default_val);
 507
 508/**
 509 * Checks whether a node is enabled.
 510 * This looks for a 'status' property. If this exists, then returns 1 if
 511 * the status is 'ok' and 0 otherwise. If there is no status property,
 512 * it returns 1 on the assumption that anything mentioned should be enabled
 513 * by default.
 514 *
 515 * @param blob  FDT blob
 516 * @param node  node to examine
 517 * @return integer value 0 (not enabled) or 1 (enabled)
 518 */
 519int fdtdec_get_is_enabled(const void *blob, int node);
 520
 521/**
 522 * Make sure we have a valid fdt available to control U-Boot.
 523 *
 524 * If not, a message is printed to the console if the console is ready.
 525 *
 526 * @return 0 if all ok, -1 if not
 527 */
 528int fdtdec_prepare_fdt(void);
 529
 530/**
 531 * Checks that we have a valid fdt available to control U-Boot.
 532
 533 * However, if not then for the moment nothing is done, since this function
 534 * is called too early to panic().
 535 *
 536 * @returns 0
 537 */
 538int fdtdec_check_fdt(void);
 539
 540/**
 541 * Find the nodes for a peripheral and return a list of them in the correct
 542 * order. This is used to enumerate all the peripherals of a certain type.
 543 *
 544 * To use this, optionally set up a /aliases node with alias properties for
 545 * a peripheral. For example, for usb you could have:
 546 *
 547 * aliases {
 548 *              usb0 = "/ehci@c5008000";
 549 *              usb1 = "/ehci@c5000000";
 550 * };
 551 *
 552 * Pass "usb" as the name to this function and will return a list of two
 553 * nodes offsets: /ehci@c5008000 and ehci@c5000000.
 554 *
 555 * All nodes returned will match the compatible ID, as it is assumed that
 556 * all peripherals use the same driver.
 557 *
 558 * If no alias node is found, then the node list will be returned in the
 559 * order found in the fdt. If the aliases mention a node which doesn't
 560 * exist, then this will be ignored. If nodes are found with no aliases,
 561 * they will be added in any order.
 562 *
 563 * If there is a gap in the aliases, then this function return a 0 node at
 564 * that position. The return value will also count these gaps.
 565 *
 566 * This function checks node properties and will not return nodes which are
 567 * marked disabled (status = "disabled").
 568 *
 569 * @param blob          FDT blob to use
 570 * @param name          Root name of alias to search for
 571 * @param id            Compatible ID to look for
 572 * @param node_list     Place to put list of found nodes
 573 * @param maxcount      Maximum number of nodes to find
 574 * @return number of nodes found on success, FDT_ERR_... on error
 575 */
 576int fdtdec_find_aliases_for_id(const void *blob, const char *name,
 577                        enum fdt_compat_id id, int *node_list, int maxcount);
 578
 579/*
 580 * This function is similar to fdtdec_find_aliases_for_id() except that it
 581 * adds to the node_list that is passed in. Any 0 elements are considered
 582 * available for allocation - others are considered already used and are
 583 * skipped.
 584 *
 585 * You can use this by calling fdtdec_find_aliases_for_id() with an
 586 * uninitialised array, then setting the elements that are returned to -1,
 587 * say, then calling this function, perhaps with a different compat id.
 588 * Any elements you get back that are >0 are new nodes added by the call
 589 * to this function.
 590 *
 591 * Note that if you have some nodes with aliases and some without, you are
 592 * sailing close to the wind. The call to fdtdec_find_aliases_for_id() with
 593 * one compat_id may fill in positions for which you have aliases defined
 594 * for another compat_id. When you later call *this* function with the second
 595 * compat_id, the alias positions may already be used. A debug warning may
 596 * be generated in this case, but it is safest to define aliases for all
 597 * nodes when you care about the ordering.
 598 */
 599int fdtdec_add_aliases_for_id(const void *blob, const char *name,
 600                        enum fdt_compat_id id, int *node_list, int maxcount);
 601
 602/**
 603 * Get the alias sequence number of a node
 604 *
 605 * This works out whether a node is pointed to by an alias, and if so, the
 606 * sequence number of that alias. Aliases are of the form <base><num> where
 607 * <num> is the sequence number. For example spi2 would be sequence number
 608 * 2.
 609 *
 610 * @param blob          Device tree blob (if NULL, then error is returned)
 611 * @param base          Base name for alias (before the underscore)
 612 * @param node          Node to look up
 613 * @param seqp          This is set to the sequence number if one is found,
 614 *                      but otherwise the value is left alone
 615 * @return 0 if a sequence was found, -ve if not
 616 */
 617int fdtdec_get_alias_seq(const void *blob, const char *base, int node,
 618                         int *seqp);
 619
 620/**
 621 * Get the highest alias number for susbystem.
 622 *
 623 * It parses all aliases and find out highest recorded alias for subsystem.
 624 * Aliases are of the form <base><num> where <num> is the sequence number.
 625 *
 626 * @param blob          Device tree blob (if NULL, then error is returned)
 627 * @param base          Base name for alias susbystem (before the number)
 628 *
 629 * @return 0 highest alias ID, -1 if not found
 630 */
 631int fdtdec_get_alias_highest_id(const void *blob, const char *base);
 632
 633/**
 634 * Get a property from the /chosen node
 635 *
 636 * @param blob          Device tree blob (if NULL, then NULL is returned)
 637 * @param name          Property name to look up
 638 * @return Value of property, or NULL if it does not exist
 639 */
 640const char *fdtdec_get_chosen_prop(const void *blob, const char *name);
 641
 642/**
 643 * Get the offset of the given /chosen node
 644 *
 645 * This looks up a property in /chosen containing the path to another node,
 646 * then finds the offset of that node.
 647 *
 648 * @param blob          Device tree blob (if NULL, then error is returned)
 649 * @param name          Property name, e.g. "stdout-path"
 650 * @return Node offset referred to by that chosen node, or -ve FDT_ERR_...
 651 */
 652int fdtdec_get_chosen_node(const void *blob, const char *name);
 653
 654/*
 655 * Get the name for a compatible ID
 656 *
 657 * @param id            Compatible ID to look for
 658 * @return compatible string for that id
 659 */
 660const char *fdtdec_get_compatible(enum fdt_compat_id id);
 661
 662/* Look up a phandle and follow it to its node. Then return the offset
 663 * of that node.
 664 *
 665 * @param blob          FDT blob
 666 * @param node          node to examine
 667 * @param prop_name     name of property to find
 668 * @return node offset if found, -ve error code on error
 669 */
 670int fdtdec_lookup_phandle(const void *blob, int node, const char *prop_name);
 671
 672/**
 673 * Look up a property in a node and return its contents in an integer
 674 * array of given length. The property must have at least enough data for
 675 * the array (4*count bytes). It may have more, but this will be ignored.
 676 *
 677 * @param blob          FDT blob
 678 * @param node          node to examine
 679 * @param prop_name     name of property to find
 680 * @param array         array to fill with data
 681 * @param count         number of array elements
 682 * @return 0 if ok, or -FDT_ERR_NOTFOUND if the property is not found,
 683 *              or -FDT_ERR_BADLAYOUT if not enough data
 684 */
 685int fdtdec_get_int_array(const void *blob, int node, const char *prop_name,
 686                u32 *array, int count);
 687
 688/**
 689 * Look up a property in a node and return its contents in an integer
 690 * array of given length. The property must exist but may have less data that
 691 * expected (4*count bytes). It may have more, but this will be ignored.
 692 *
 693 * @param blob          FDT blob
 694 * @param node          node to examine
 695 * @param prop_name     name of property to find
 696 * @param array         array to fill with data
 697 * @param count         number of array elements
 698 * @return number of array elements if ok, or -FDT_ERR_NOTFOUND if the
 699 *              property is not found
 700 */
 701int fdtdec_get_int_array_count(const void *blob, int node,
 702                               const char *prop_name, u32 *array, int count);
 703
 704/**
 705 * Look up a property in a node and return a pointer to its contents as a
 706 * unsigned int array of given length. The property must have at least enough
 707 * data for the array ('count' cells). It may have more, but this will be
 708 * ignored. The data is not copied.
 709 *
 710 * Note that you must access elements of the array with fdt32_to_cpu(),
 711 * since the elements will be big endian even on a little endian machine.
 712 *
 713 * @param blob          FDT blob
 714 * @param node          node to examine
 715 * @param prop_name     name of property to find
 716 * @param count         number of array elements
 717 * @return pointer to array if found, or NULL if the property is not
 718 *              found or there is not enough data
 719 */
 720const u32 *fdtdec_locate_array(const void *blob, int node,
 721                               const char *prop_name, int count);
 722
 723/**
 724 * Look up a boolean property in a node and return it.
 725 *
 726 * A boolean properly is true if present in the device tree and false if not
 727 * present, regardless of its value.
 728 *
 729 * @param blob  FDT blob
 730 * @param node  node to examine
 731 * @param prop_name     name of property to find
 732 * @return 1 if the properly is present; 0 if it isn't present
 733 */
 734int fdtdec_get_bool(const void *blob, int node, const char *prop_name);
 735
 736/*
 737 * Count child nodes of one parent node.
 738 *
 739 * @param blob  FDT blob
 740 * @param node  parent node
 741 * @return number of child node; 0 if there is not child node
 742 */
 743int fdtdec_get_child_count(const void *blob, int node);
 744
 745/*
 746 * Look up a property in a node and return its contents in a byte
 747 * array of given length. The property must have at least enough data for
 748 * the array (count bytes). It may have more, but this will be ignored.
 749 *
 750 * @param blob          FDT blob
 751 * @param node          node to examine
 752 * @param prop_name     name of property to find
 753 * @param array         array to fill with data
 754 * @param count         number of array elements
 755 * @return 0 if ok, or -FDT_ERR_MISSING if the property is not found,
 756 *              or -FDT_ERR_BADLAYOUT if not enough data
 757 */
 758int fdtdec_get_byte_array(const void *blob, int node, const char *prop_name,
 759                u8 *array, int count);
 760
 761/**
 762 * Look up a property in a node and return a pointer to its contents as a
 763 * byte array of given length. The property must have at least enough data
 764 * for the array (count bytes). It may have more, but this will be ignored.
 765 * The data is not copied.
 766 *
 767 * @param blob          FDT blob
 768 * @param node          node to examine
 769 * @param prop_name     name of property to find
 770 * @param count         number of array elements
 771 * @return pointer to byte array if found, or NULL if the property is not
 772 *              found or there is not enough data
 773 */
 774const u8 *fdtdec_locate_byte_array(const void *blob, int node,
 775                             const char *prop_name, int count);
 776
 777/**
 778 * Obtain an indexed resource from a device property.
 779 *
 780 * @param fdt           FDT blob
 781 * @param node          node to examine
 782 * @param property      name of the property to parse
 783 * @param index         index of the resource to retrieve
 784 * @param res           returns the resource
 785 * @return 0 if ok, negative on error
 786 */
 787int fdt_get_resource(const void *fdt, int node, const char *property,
 788                     unsigned int index, struct fdt_resource *res);
 789
 790/**
 791 * Obtain a named resource from a device property.
 792 *
 793 * Look up the index of the name in a list of strings and return the resource
 794 * at that index.
 795 *
 796 * @param fdt           FDT blob
 797 * @param node          node to examine
 798 * @param property      name of the property to parse
 799 * @param prop_names    name of the property containing the list of names
 800 * @param name          the name of the entry to look up
 801 * @param res           returns the resource
 802 */
 803int fdt_get_named_resource(const void *fdt, int node, const char *property,
 804                           const char *prop_names, const char *name,
 805                           struct fdt_resource *res);
 806
 807/* Display timings from linux include/video/display_timing.h */
 808enum display_flags {
 809        DISPLAY_FLAGS_HSYNC_LOW         = 1 << 0,
 810        DISPLAY_FLAGS_HSYNC_HIGH        = 1 << 1,
 811        DISPLAY_FLAGS_VSYNC_LOW         = 1 << 2,
 812        DISPLAY_FLAGS_VSYNC_HIGH        = 1 << 3,
 813
 814        /* data enable flag */
 815        DISPLAY_FLAGS_DE_LOW            = 1 << 4,
 816        DISPLAY_FLAGS_DE_HIGH           = 1 << 5,
 817        /* drive data on pos. edge */
 818        DISPLAY_FLAGS_PIXDATA_POSEDGE   = 1 << 6,
 819        /* drive data on neg. edge */
 820        DISPLAY_FLAGS_PIXDATA_NEGEDGE   = 1 << 7,
 821        DISPLAY_FLAGS_INTERLACED        = 1 << 8,
 822        DISPLAY_FLAGS_DOUBLESCAN        = 1 << 9,
 823        DISPLAY_FLAGS_DOUBLECLK         = 1 << 10,
 824};
 825
 826/*
 827 * A single signal can be specified via a range of minimal and maximal values
 828 * with a typical value, that lies somewhere inbetween.
 829 */
 830struct timing_entry {
 831        u32 min;
 832        u32 typ;
 833        u32 max;
 834};
 835
 836/*
 837 * Single "mode" entry. This describes one set of signal timings a display can
 838 * have in one setting. This struct can later be converted to struct videomode
 839 * (see include/video/videomode.h). As each timing_entry can be defined as a
 840 * range, one struct display_timing may become multiple struct videomodes.
 841 *
 842 * Example: hsync active high, vsync active low
 843 *
 844 *                                  Active Video
 845 * Video  ______________________XXXXXXXXXXXXXXXXXXXXXX_____________________
 846 *        |<- sync ->|<- back ->|<----- active ----->|<- front ->|<- sync..
 847 *        |          |   porch  |                    |   porch   |
 848 *
 849 * HSync _|¯¯¯¯¯¯¯¯¯¯|___________________________________________|¯¯¯¯¯¯¯¯¯
 850 *
 851 * VSync ¯|__________|¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯|_________
 852 */
 853struct display_timing {
 854        struct timing_entry pixelclock;
 855
 856        struct timing_entry hactive;            /* hor. active video */
 857        struct timing_entry hfront_porch;       /* hor. front porch */
 858        struct timing_entry hback_porch;        /* hor. back porch */
 859        struct timing_entry hsync_len;          /* hor. sync len */
 860
 861        struct timing_entry vactive;            /* ver. active video */
 862        struct timing_entry vfront_porch;       /* ver. front porch */
 863        struct timing_entry vback_porch;        /* ver. back porch */
 864        struct timing_entry vsync_len;          /* ver. sync len */
 865
 866        enum display_flags flags;               /* display flags */
 867        bool hdmi_monitor;                      /* is hdmi monitor? */
 868};
 869
 870/**
 871 * fdtdec_decode_display_timing() - decode display timings
 872 *
 873 * Decode display timings from the supplied 'display-timings' node.
 874 * See doc/device-tree-bindings/video/display-timing.txt for binding
 875 * information.
 876 *
 877 * @param blob          FDT blob
 878 * @param node          'display-timing' node containing the timing subnodes
 879 * @param index         Index number to read (0=first timing subnode)
 880 * @param config        Place to put timings
 881 * @return 0 if OK, -FDT_ERR_NOTFOUND if not found
 882 */
 883int fdtdec_decode_display_timing(const void *blob, int node, int index,
 884                                 struct display_timing *config);
 885
 886/**
 887 * fdtdec_setup_mem_size_base() - decode and setup gd->ram_size and
 888 * gd->ram_start
 889 *
 890 * Decode the /memory 'reg' property to determine the size and start of the
 891 * first memory bank, populate the global data with the size and start of the
 892 * first bank of memory.
 893 *
 894 * This function should be called from a boards dram_init(). This helper
 895 * function allows for boards to query the device tree for DRAM size and start
 896 * address instead of hard coding the value in the case where the memory size
 897 * and start address cannot be detected automatically.
 898 *
 899 * @return 0 if OK, -EINVAL if the /memory node or reg property is missing or
 900 * invalid
 901 */
 902int fdtdec_setup_mem_size_base(void);
 903
 904/**
 905 * fdtdec_setup_mem_size_base_lowest() - decode and setup gd->ram_size and
 906 * gd->ram_start by lowest available memory base
 907 *
 908 * Decode the /memory 'reg' property to determine the lowest start of the memory
 909 * bank bank and populate the global data with it.
 910 *
 911 * This function should be called from a boards dram_init(). This helper
 912 * function allows for boards to query the device tree for DRAM size and start
 913 * address instead of hard coding the value in the case where the memory size
 914 * and start address cannot be detected automatically.
 915 *
 916 * @return 0 if OK, -EINVAL if the /memory node or reg property is missing or
 917 * invalid
 918 */
 919int fdtdec_setup_mem_size_base_lowest(void);
 920
 921/**
 922 * fdtdec_setup_memory_banksize() - decode and populate gd->bd->bi_dram
 923 *
 924 * Decode the /memory 'reg' property to determine the address and size of the
 925 * memory banks. Use this data to populate the global data board info with the
 926 * phys address and size of memory banks.
 927 *
 928 * This function should be called from a boards dram_init_banksize(). This
 929 * helper function allows for boards to query the device tree for memory bank
 930 * information instead of hard coding the information in cases where it cannot
 931 * be detected automatically.
 932 *
 933 * @return 0 if OK, -EINVAL if the /memory node or reg property is missing or
 934 * invalid
 935 */
 936int fdtdec_setup_memory_banksize(void);
 937
 938/**
 939 * fdtdec_set_ethernet_mac_address() - set MAC address for default interface
 940 *
 941 * Looks up the default interface via the "ethernet" alias (in the /aliases
 942 * node) and stores the given MAC in its "local-mac-address" property. This
 943 * is useful on platforms that store the MAC address in a custom location.
 944 * Board code can call this in the late init stage to make sure that the
 945 * interface device tree node has the right MAC address configured for the
 946 * Ethernet uclass to pick it up.
 947 *
 948 * Typically the FDT passed into this function will be U-Boot's control DTB.
 949 * Given that a lot of code may be holding offsets to various nodes in that
 950 * tree, this code will only set the "local-mac-address" property in-place,
 951 * which means that it needs to exist and have space for the 6-byte address.
 952 * This ensures that the operation is non-destructive and does not invalidate
 953 * offsets that other drivers may be using.
 954 *
 955 * @param fdt FDT blob
 956 * @param mac buffer containing the MAC address to set
 957 * @param size size of MAC address
 958 * @return 0 on success or a negative error code on failure
 959 */
 960int fdtdec_set_ethernet_mac_address(void *fdt, const u8 *mac, size_t size);
 961
 962/**
 963 * fdtdec_set_phandle() - sets the phandle of a given node
 964 *
 965 * @param blob          FDT blob
 966 * @param node          offset in the FDT blob of the node whose phandle is to
 967 *                      be set
 968 * @param phandle       phandle to set for the given node
 969 * @return 0 on success or a negative error code on failure
 970 */
 971static inline int fdtdec_set_phandle(void *blob, int node, uint32_t phandle)
 972{
 973        return fdt_setprop_u32(blob, node, "phandle", phandle);
 974}
 975
 976/* add "no-map" property */
 977#define FDTDEC_RESERVED_MEMORY_NO_MAP (1 << 0)
 978
 979/**
 980 * fdtdec_add_reserved_memory() - add or find a reserved-memory node
 981 *
 982 * If a reserved-memory node already exists for the given carveout, a phandle
 983 * for that node will be returned. Otherwise a new node will be created and a
 984 * phandle corresponding to it will be returned.
 985 *
 986 * See Documentation/devicetree/bindings/reserved-memory/reserved-memory.txt
 987 * for details on how to use reserved memory regions.
 988 *
 989 * As an example, consider the following code snippet:
 990 *
 991 *     struct fdt_memory fb = {
 992 *         .start = 0x92cb3000,
 993 *         .end = 0x934b2fff,
 994 *     };
 995 *     uint32_t phandle;
 996 *
 997 *     fdtdec_add_reserved_memory(fdt, "framebuffer", &fb, NULL, 0, &phandle,
 998 *                                0);
 999 *
1000 * This results in the following subnode being added to the top-level
1001 * /reserved-memory node:
1002 *
1003 *     reserved-memory {
1004 *         #address-cells = <0x00000002>;
1005 *         #size-cells = <0x00000002>;
1006 *         ranges;
1007 *
1008 *         framebuffer@92cb3000 {
1009 *             reg = <0x00000000 0x92cb3000 0x00000000 0x00800000>;
1010 *             phandle = <0x0000004d>;
1011 *         };
1012 *     };
1013 *
1014 * If the top-level /reserved-memory node does not exist, it will be created.
1015 * The phandle returned from the function call can be used to reference this
1016 * reserved memory region from other nodes.
1017 *
1018 * See fdtdec_set_carveout() for a more elaborate example.
1019 *
1020 * @param blob          FDT blob
1021 * @param basename      base name of the node to create
1022 * @param carveout      information about the carveout region
1023 * @param compatibles   list of compatible strings for the carveout region
1024 * @param count         number of compatible strings for the carveout region
1025 * @param phandlep      return location for the phandle of the carveout region
1026 *                      can be NULL if no phandle should be added
1027 * @param flags         bitmask of flags to set for the carveout region
1028 * @return 0 on success or a negative error code on failure
1029 */
1030int fdtdec_add_reserved_memory(void *blob, const char *basename,
1031                               const struct fdt_memory *carveout,
1032                               const char **compatibles, unsigned int count,
1033                               uint32_t *phandlep, unsigned long flags);
1034
1035/**
1036 * fdtdec_get_carveout() - reads a carveout from an FDT
1037 *
1038 * Reads information about a carveout region from an FDT. The carveout is a
1039 * referenced by its phandle that is read from a given property in a given
1040 * node.
1041 *
1042 * @param blob          FDT blob
1043 * @param node          name of a node
1044 * @param prop_name     name of the property in the given node that contains
1045 *                      the phandle for the carveout
1046 * @param index         index of the phandle for which to read the carveout
1047 * @param carveout      return location for the carveout information
1048 * @param name          return location for the carveout name
1049 * @param compatiblesp  return location for compatible strings
1050 * @param countp        return location for the number of compatible strings
1051 * @param flags         return location for the flags of the carveout
1052 * @return 0 on success or a negative error code on failure
1053 */
1054int fdtdec_get_carveout(const void *blob, const char *node,
1055                        const char *prop_name, unsigned int index,
1056                        struct fdt_memory *carveout, const char **name,
1057                        const char ***compatiblesp, unsigned int *countp,
1058                        unsigned long *flags);
1059
1060/**
1061 * fdtdec_set_carveout() - sets a carveout region for a given node
1062 *
1063 * Sets a carveout region for a given node. If a reserved-memory node already
1064 * exists for the carveout, the phandle for that node will be reused. If no
1065 * such node exists, a new one will be created and a phandle to it stored in
1066 * a specified property of the given node.
1067 *
1068 * As an example, consider the following code snippet:
1069 *
1070 *     const char *node = "/host1x@50000000/dc@54240000";
1071 *     struct fdt_memory fb = {
1072 *         .start = 0x92cb3000,
1073 *         .end = 0x934b2fff,
1074 *     };
1075 *
1076 *     fdtdec_set_carveout(fdt, node, "memory-region", 0, "framebuffer", NULL,
1077 *                         0, &fb, 0);
1078 *
1079 * dc@54200000 is a display controller and was set up by the bootloader to
1080 * scan out the framebuffer specified by "fb". This would cause the following
1081 * reserved memory region to be added:
1082 *
1083 *     reserved-memory {
1084 *         #address-cells = <0x00000002>;
1085 *         #size-cells = <0x00000002>;
1086 *         ranges;
1087 *
1088 *         framebuffer@92cb3000 {
1089 *             reg = <0x00000000 0x92cb3000 0x00000000 0x00800000>;
1090 *             phandle = <0x0000004d>;
1091 *         };
1092 *     };
1093 *
1094 * A "memory-region" property will also be added to the node referenced by the
1095 * offset parameter.
1096 *
1097 *     host1x@50000000 {
1098 *         ...
1099 *
1100 *         dc@54240000 {
1101 *             ...
1102 *             memory-region = <0x0000004d>;
1103 *             ...
1104 *         };
1105 *
1106 *         ...
1107 *     };
1108 *
1109 * @param blob          FDT blob
1110 * @param node          name of the node to add the carveout to
1111 * @param prop_name     name of the property in which to store the phandle of
1112 *                      the carveout
1113 * @param index         index of the phandle to store
1114 * @param carveout      information about the carveout to add
1115 * @param name          base name of the reserved-memory node to create
1116 * @param compatibles   compatible strings to set for the carveout
1117 * @param count         number of compatible strings
1118 * @param flags         bitmask of flags to set for the carveout
1119 * @return 0 on success or a negative error code on failure
1120 */
1121int fdtdec_set_carveout(void *blob, const char *node, const char *prop_name,
1122                        unsigned int index, const struct fdt_memory *carveout,
1123                        const char *name, const char **compatibles,
1124                        unsigned int count, unsigned long flags);
1125
1126/**
1127 * Set up the device tree ready for use
1128 */
1129int fdtdec_setup(void);
1130
1131/**
1132 * Perform board-specific early DT adjustments
1133 */
1134int fdtdec_board_setup(const void *fdt_blob);
1135
1136#if CONFIG_IS_ENABLED(MULTI_DTB_FIT)
1137/**
1138 * fdtdec_resetup()  - Set up the device tree again
1139 *
1140 * The main difference with fdtdec_setup() is that it returns if the fdt has
1141 * changed because a better match has been found.
1142 * This is typically used for boards that rely on a DM driver to detect the
1143 * board type. This function sould be called by the board code after the stuff
1144 * needed by board_fit_config_name_match() to operate porperly is available.
1145 * If this functions signals that a rescan is necessary, the board code must
1146 * unbind all the drivers using dm_uninit() and then rescan the DT with
1147 * dm_init_and_scan().
1148 *
1149 * @param rescan Returns a flag indicating that fdt has changed and rescanning
1150 *               the fdt is required
1151 *
1152 * @return 0 if OK, -ve on error
1153 */
1154int fdtdec_resetup(int *rescan);
1155#endif
1156
1157/**
1158 * Board-specific FDT initialization. Returns the address to a device tree blob.
1159 * Called when CONFIG_OF_BOARD is defined, or if CONFIG_OF_SEPARATE is defined
1160 * and the board implements it.
1161 *
1162 * @err internal error code if we fail to setup a DTB
1163 */
1164void *board_fdt_blob_setup(int *err);
1165
1166/*
1167 * Decode the size of memory
1168 *
1169 * RAM size is normally set in a /memory node and consists of a list of
1170 * (base, size) cells in the 'reg' property. This information is used to
1171 * determine the total available memory as well as the address and size
1172 * of each bank.
1173 *
1174 * Optionally the memory configuration can vary depending on a board id,
1175 * typically read from strapping resistors or an EEPROM on the board.
1176 *
1177 * Finally, memory size can be detected (within certain limits) by probing
1178 * the available memory. It is safe to do so within the limits provides by
1179 * the board's device tree information. This makes it possible to produce
1180 * boards with different memory sizes, where the device tree specifies the
1181 * maximum memory configuration, and the smaller memory configuration is
1182 * probed.
1183 *
1184 * This function decodes that information, returning the memory base address,
1185 * size and bank information. See the memory.txt binding for full
1186 * documentation.
1187 *
1188 * @param blob          Device tree blob
1189 * @param area          Name of node to check (NULL means "/memory")
1190 * @param board_id      Board ID to look up
1191 * @param basep         Returns base address of first memory bank (NULL to
1192 *                      ignore)
1193 * @param sizep         Returns total memory size (NULL to ignore)
1194 * @param bd            Updated with the memory bank information (NULL to skip)
1195 * @return 0 if OK, -ve on error
1196 */
1197int fdtdec_decode_ram_size(const void *blob, const char *area, int board_id,
1198                           phys_addr_t *basep, phys_size_t *sizep,
1199                           struct bd_info *bd);
1200
1201#endif
1202