include/fdtdec.h

   1 /*
   2  * Copyright (c) 2011 The Chromium OS Authors.
   3  * SPDX-License-Identifier:     GPL-2.0+
   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 <libfdt.h>
  18
  19 /*
  20  * A typedef for a physical address. Note that fdt data is always big
  21  * endian even on a litle endian machine.
  22  */
  23 #ifdef CONFIG_PHYS_64BIT
  24 typedef u64 fdt_addr_t;
  25 typedef u64 fdt_size_t;
  26 #define FDT_ADDR_T_NONE (-1ULL)
  27 #define fdt_addr_to_cpu(reg) be64_to_cpu(reg)
  28 #define fdt_size_to_cpu(reg) be64_to_cpu(reg)
  29 #else
  30 typedef u32 fdt_addr_t;
  31 typedef u32 fdt_size_t;
  32 #define FDT_ADDR_T_NONE (-1U)
  33 #define fdt_addr_to_cpu(reg) be32_to_cpu(reg)
  34 #define fdt_size_to_cpu(reg) be32_to_cpu(reg)
  35 #endif
  36
  37 /* Information obtained about memory from the FDT */
  38 struct fdt_memory {
  39         fdt_addr_t start;
  40         fdt_addr_t end;
  41 };
  42
  43 /**
  44  * Compat types that we know about and for which we might have drivers.
  45  * Each is named COMPAT_<dir>_<filename> where <dir> is the directory
  46  * within drivers.
  47  */
  48 enum fdt_compat_id {
  49         COMPAT_UNKNOWN,
  50         COMPAT_NVIDIA_TEGRA20_USB,      /* Tegra20 USB port */
  51         COMPAT_NVIDIA_TEGRA30_USB,      /* Tegra30 USB port */
  52         COMPAT_NVIDIA_TEGRA114_USB,     /* Tegra114 USB port */
  53         COMPAT_NVIDIA_TEGRA114_I2C,     /* Tegra114 I2C w/single clock source */
  54         COMPAT_NVIDIA_TEGRA20_I2C,      /* Tegra20 i2c */
  55         COMPAT_NVIDIA_TEGRA20_DVC,      /* Tegra20 dvc (really just i2c) */
  56         COMPAT_NVIDIA_TEGRA20_EMC,      /* Tegra20 memory controller */
  57         COMPAT_NVIDIA_TEGRA20_EMC_TABLE, /* Tegra20 memory timing table */
  58         COMPAT_NVIDIA_TEGRA20_KBC,      /* Tegra20 Keyboard */
  59         COMPAT_NVIDIA_TEGRA20_NAND,     /* Tegra2 NAND controller */
  60         COMPAT_NVIDIA_TEGRA20_PWM,      /* Tegra 2 PWM controller */
  61         COMPAT_NVIDIA_TEGRA20_DC,       /* Tegra 2 Display controller */
  62         COMPAT_NVIDIA_TEGRA124_SDMMC,   /* Tegra124 SDMMC controller */
  63         COMPAT_NVIDIA_TEGRA30_SDMMC,    /* Tegra30 SDMMC controller */
  64         COMPAT_NVIDIA_TEGRA20_SDMMC,    /* Tegra20 SDMMC controller */
  65         COMPAT_NVIDIA_TEGRA20_SFLASH,   /* Tegra 2 SPI flash controller */
  66         COMPAT_NVIDIA_TEGRA20_SLINK,    /* Tegra 2 SPI SLINK controller */
  67         COMPAT_NVIDIA_TEGRA114_SPI,     /* Tegra 114 SPI controller */
  68         COMPAT_SMSC_LAN9215,            /* SMSC 10/100 Ethernet LAN9215 */
  69         COMPAT_SAMSUNG_EXYNOS5_SROMC,   /* Exynos5 SROMC */
  70         COMPAT_SAMSUNG_S3C2440_I2C,     /* Exynos I2C Controller */
  71         COMPAT_SAMSUNG_EXYNOS5_SOUND,   /* Exynos Sound */
  72         COMPAT_WOLFSON_WM8994_CODEC,    /* Wolfson WM8994 Sound Codec */
  73         COMPAT_SAMSUNG_EXYNOS_SPI,      /* Exynos SPI */
  74         COMPAT_GOOGLE_CROS_EC,          /* Google CROS_EC Protocol */
  75         COMPAT_GOOGLE_CROS_EC_KEYB,     /* Google CROS_EC Keyboard */
  76         COMPAT_SAMSUNG_EXYNOS_EHCI,     /* Exynos EHCI controller */
  77         COMPAT_SAMSUNG_EXYNOS5_XHCI,    /* Exynos5 XHCI controller */
  78         COMPAT_SAMSUNG_EXYNOS_USB_PHY,  /* Exynos phy controller for usb2.0 */
  79         COMPAT_SAMSUNG_EXYNOS5_USB3_PHY,/* Exynos phy controller for usb3.0 */
  80         COMPAT_SAMSUNG_EXYNOS_TMU,      /* Exynos TMU */
  81         COMPAT_SAMSUNG_EXYNOS_FIMD,     /* Exynos Display controller */
  82         COMPAT_SAMSUNG_EXYNOS_MIPI_DSI, /* Exynos mipi dsi */
  83         COMPAT_SAMSUNG_EXYNOS5_DP,      /* Exynos Display port controller */
  84         COMPAT_SAMSUNG_EXYNOS_DWMMC,    /* Exynos DWMMC controller */
  85         COMPAT_SAMSUNG_EXYNOS_MMC,      /* Exynos MMC controller */
  86         COMPAT_SAMSUNG_EXYNOS_SERIAL,   /* Exynos UART */
  87         COMPAT_MAXIM_MAX77686_PMIC,     /* MAX77686 PMIC */
  88         COMPAT_GENERIC_SPI_FLASH,       /* Generic SPI Flash chip */
  89         COMPAT_MAXIM_98095_CODEC,       /* MAX98095 Codec */
  90         COMPAT_INFINEON_SLB9635_TPM,    /* Infineon SLB9635 TPM */
  91         COMPAT_INFINEON_SLB9645_TPM,    /* Infineon SLB9645 TPM */
  92         COMPAT_SAMSUNG_EXYNOS5_I2C,     /* Exynos5 High Speed I2C Controller */
  93         COMPAT_SANDBOX_HOST_EMULATION,  /* Sandbox emulation of a function */
  94         COMPAT_SANDBOX_LCD_SDL,         /* Sandbox LCD emulation with SDL */
  95         COMPAT_TI_TPS65090,             /* Texas Instrument TPS65090 */
  96         COMPAT_NXP_PTN3460,             /* NXP PTN3460 DP/LVDS bridge */
  97         COMPAT_SAMSUNG_EXYNOS_SYSMMU,   /* Exynos sysmmu */
  98         COMPAT_PARADE_PS8625,           /* Parade PS8622 EDP->LVDS bridge */
  99
 100         COMPAT_COUNT,
 101 };
 102
 103 /* GPIOs are numbered from 0 */
 104 enum {
 105         FDT_GPIO_NONE = -1U,    /* an invalid GPIO used to end our list */
 106
 107         FDT_GPIO_ACTIVE_LOW = 1 << 0,   /* input is active low (else high) */
 108 };
 109
 110 /* This is the state of a GPIO pin as defined by the fdt */
 111 struct fdt_gpio_state {
 112         const char *name;       /* name of the fdt property defining this */
 113         uint gpio;              /* GPIO number, or FDT_GPIO_NONE if none */
 114         u8 flags;               /* FDT_GPIO_... flags */
 115 };
 116
 117 /* This tells us whether a fdt_gpio_state record is valid or not */
 118 #define fdt_gpio_isvalid(x) ((x)->gpio != FDT_GPIO_NONE)
 119
 120 /**
 121  * Read the GPIO taking into account the polarity of the pin.
 122  *
 123  * @param gpio          pointer to the decoded gpio
 124  * @return value of the gpio if successful, < 0 if unsuccessful
 125  */
 126 int fdtdec_get_gpio(struct fdt_gpio_state *gpio);
 127
 128 /**
 129  * Write the GPIO taking into account the polarity of the pin.
 130  *
 131  * @param gpio          pointer to the decoded gpio
 132  * @return 0 if successful
 133  */
 134 int fdtdec_set_gpio(struct fdt_gpio_state *gpio, int val);
 135
 136 /**
 137  * Find the next numbered alias for a peripheral. This is used to enumerate
 138  * all the peripherals of a certain type.
 139  *
 140  * Do the first call with *upto = 0. Assuming /aliases/<name>0 exists then
 141  * this function will return a pointer to the node the alias points to, and
 142  * then update *upto to 1. Next time you call this function, the next node
 143  * will be returned.
 144  *
 145  * All nodes returned will match the compatible ID, as it is assumed that
 146  * all peripherals use the same driver.
 147  *
 148  * @param blob          FDT blob to use
 149  * @param name          Root name of alias to search for
 150  * @param id            Compatible ID to look for
 151  * @return offset of next compatible node, or -FDT_ERR_NOTFOUND if no more
 152  */
 153 int fdtdec_next_alias(const void *blob, const char *name,
 154                 enum fdt_compat_id id, int *upto);
 155
 156 /**
 157  * Find the compatible ID for a given node.
 158  *
 159  * Generally each node has at least one compatible string attached to it.
 160  * This function looks through our list of known compatible strings and
 161  * returns the corresponding ID which matches the compatible string.
 162  *
 163  * @param blob          FDT blob to use
 164  * @param node          Node containing compatible string to find
 165  * @return compatible ID, or COMPAT_UNKNOWN if we cannot find a match
 166  */
 167 enum fdt_compat_id fdtdec_lookup(const void *blob, int node);
 168
 169 /**
 170  * Find the next compatible node for a peripheral.
 171  *
 172  * Do the first call with node = 0. This function will return a pointer to
 173  * the next compatible node. Next time you call this function, pass the
 174  * value returned, and the next node will be provided.
 175  *
 176  * @param blob          FDT blob to use
 177  * @param node          Start node for search
 178  * @param id            Compatible ID to look for (enum fdt_compat_id)
 179  * @return offset of next compatible node, or -FDT_ERR_NOTFOUND if no more
 180  */
 181 int fdtdec_next_compatible(const void *blob, int node,
 182                 enum fdt_compat_id id);
 183
 184 /**
 185  * Find the next compatible subnode for a peripheral.
 186  *
 187  * Do the first call with node set to the parent and depth = 0. This
 188  * function will return the offset of the next compatible node. Next time
 189  * you call this function, pass the node value returned last time, with
 190  * depth unchanged, and the next node will be provided.
 191  *
 192  * @param blob          FDT blob to use
 193  * @param node          Start node for search
 194  * @param id            Compatible ID to look for (enum fdt_compat_id)
 195  * @param depthp        Current depth (set to 0 before first call)
 196  * @return offset of next compatible node, or -FDT_ERR_NOTFOUND if no more
 197  */
 198 int fdtdec_next_compatible_subnode(const void *blob, int node,
 199                 enum fdt_compat_id id, int *depthp);
 200
 201 /**
 202  * Look up an address property in a node and return it as an address.
 203  * The property must hold either one address with no trailing data or
 204  * one address with a length. This is only tested on 32-bit machines.
 205  *
 206  * @param blob  FDT blob
 207  * @param node  node to examine
 208  * @param prop_name     name of property to find
 209  * @return address, if found, or FDT_ADDR_T_NONE if not
 210  */
 211 fdt_addr_t fdtdec_get_addr(const void *blob, int node,
 212                 const char *prop_name);
 213
 214 /**
 215  * Look up an address property in a node and return it as an address.
 216  * The property must hold one address with a length. This is only tested
 217  * on 32-bit machines.
 218  *
 219  * @param blob  FDT blob
 220  * @param node  node to examine
 221  * @param prop_name     name of property to find
 222  * @return address, if found, or FDT_ADDR_T_NONE if not
 223  */
 224 fdt_addr_t fdtdec_get_addr_size(const void *blob, int node,
 225                 const char *prop_name, fdt_size_t *sizep);
 226
 227 /**
 228  * Look up a 32-bit integer property in a node and return it. The property
 229  * must have at least 4 bytes of data. The value of the first cell is
 230  * returned.
 231  *
 232  * @param blob  FDT blob
 233  * @param node  node to examine
 234  * @param prop_name     name of property to find
 235  * @param default_val   default value to return if the property is not found
 236  * @return integer value, if found, or default_val if not
 237  */
 238 s32 fdtdec_get_int(const void *blob, int node, const char *prop_name,
 239                 s32 default_val);
 240
 241 /**
 242  * Look up a 64-bit integer property in a node and return it. The property
 243  * must have at least 8 bytes of data (2 cells). The first two cells are
 244  * concatenated to form a 8 bytes value, where the first cell is top half and
 245  * the second cell is bottom half.
 246  *
 247  * @param blob  FDT blob
 248  * @param node  node to examine
 249  * @param prop_name     name of property to find
 250  * @param default_val   default value to return if the property is not found
 251  * @return integer value, if found, or default_val if not
 252  */
 253 uint64_t fdtdec_get_uint64(const void *blob, int node, const char *prop_name,
 254                 uint64_t default_val);
 255
 256 /**
 257  * Checks whether a node is enabled.
 258  * This looks for a 'status' property. If this exists, then returns 1 if
 259  * the status is 'ok' and 0 otherwise. If there is no status property,
 260  * it returns 1 on the assumption that anything mentioned should be enabled
 261  * by default.
 262  *
 263  * @param blob  FDT blob
 264  * @param node  node to examine
 265  * @return integer value 0 (not enabled) or 1 (enabled)
 266  */
 267 int fdtdec_get_is_enabled(const void *blob, int node);
 268
 269 /**
 270  * Make sure we have a valid fdt available to control U-Boot.
 271  *
 272  * If not, a message is printed to the console if the console is ready.
 273  *
 274  * @return 0 if all ok, -1 if not
 275  */
 276 int fdtdec_prepare_fdt(void);
 277
 278 /**
 279  * Checks that we have a valid fdt available to control U-Boot.
 280
 281  * However, if not then for the moment nothing is done, since this function
 282  * is called too early to panic().
 283  *
 284  * @returns 0
 285  */
 286 int fdtdec_check_fdt(void);
 287
 288 /**
 289  * Find the nodes for a peripheral and return a list of them in the correct
 290  * order. This is used to enumerate all the peripherals of a certain type.
 291  *
 292  * To use this, optionally set up a /aliases node with alias properties for
 293  * a peripheral. For example, for usb you could have:
 294  *
 295  * aliases {
 296  *              usb0 = "/ehci@c5008000";
 297  *              usb1 = "/ehci@c5000000";
 298  * };
 299  *
 300  * Pass "usb" as the name to this function and will return a list of two
 301  * nodes offsets: /ehci@c5008000 and ehci@c5000000.
 302  *
 303  * All nodes returned will match the compatible ID, as it is assumed that
 304  * all peripherals use the same driver.
 305  *
 306  * If no alias node is found, then the node list will be returned in the
 307  * order found in the fdt. If the aliases mention a node which doesn't
 308  * exist, then this will be ignored. If nodes are found with no aliases,
 309  * they will be added in any order.
 310  *
 311  * If there is a gap in the aliases, then this function return a 0 node at
 312  * that position. The return value will also count these gaps.
 313  *
 314  * This function checks node properties and will not return nodes which are
 315  * marked disabled (status = "disabled").
 316  *
 317  * @param blob          FDT blob to use
 318  * @param name          Root name of alias to search for
 319  * @param id            Compatible ID to look for
 320  * @param node_list     Place to put list of found nodes
 321  * @param maxcount      Maximum number of nodes to find
 322  * @return number of nodes found on success, FTD_ERR_... on error
 323  */
 324 int fdtdec_find_aliases_for_id(const void *blob, const char *name,
 325                         enum fdt_compat_id id, int *node_list, int maxcount);
 326
 327 /*
 328  * This function is similar to fdtdec_find_aliases_for_id() except that it
 329  * adds to the node_list that is passed in. Any 0 elements are considered
 330  * available for allocation - others are considered already used and are
 331  * skipped.
 332  *
 333  * You can use this by calling fdtdec_find_aliases_for_id() with an
 334  * uninitialised array, then setting the elements that are returned to -1,
 335  * say, then calling this function, perhaps with a different compat id.
 336  * Any elements you get back that are >0 are new nodes added by the call
 337  * to this function.
 338  *
 339  * Note that if you have some nodes with aliases and some without, you are
 340  * sailing close to the wind. The call to fdtdec_find_aliases_for_id() with
 341  * one compat_id may fill in positions for which you have aliases defined
 342  * for another compat_id. When you later call *this* function with the second
 343  * compat_id, the alias positions may already be used. A debug warning may
 344  * be generated in this case, but it is safest to define aliases for all
 345  * nodes when you care about the ordering.
 346  */
 347 int fdtdec_add_aliases_for_id(const void *blob, const char *name,
 348                         enum fdt_compat_id id, int *node_list, int maxcount);
 349
 350 /**
 351  * Get the alias sequence number of a node
 352  *
 353  * This works out whether a node is pointed to by an alias, and if so, the
 354  * sequence number of that alias. Aliases are of the form <base><num> where
 355  * <num> is the sequence number. For example spi2 would be sequence number
 356  * 2.
 357  *
 358  * @param blob          Device tree blob (if NULL, then error is returned)
 359  * @param base          Base name for alias (before the underscore)
 360  * @param node          Node to look up
 361  * @param seqp          This is set to the sequence number if one is found,
 362  *                      but otherwise the value is left alone
 363  * @return 0 if a sequence was found, -ve if not
 364  */
 365 int fdtdec_get_alias_seq(const void *blob, const char *base, int node,
 366                          int *seqp);
 367
 368 /**
 369  * Get the offset of the given alias node
 370  *
 371  * This looks up an alias in /aliases then finds the offset of that node.
 372  *
 373  * @param blob          Device tree blob (if NULL, then error is returned)
 374  * @param name          Alias name, e.g. "console"
 375  * @return Node offset referred to by that alias, or -ve FDT_ERR_...
 376  */
 377 int fdtdec_get_alias_node(const void *blob, const char *name);
 378
 379 /**
 380  * Get the offset of the given chosen node
 381  *
 382  * This looks up a property in /chosen containing the path to another node,
 383  * then finds the offset of that node.
 384  *
 385  * @param blob          Device tree blob (if NULL, then error is returned)
 386  * @param name          Property name, e.g. "stdout-path"
 387  * @return Node offset referred to by that chosen node, or -ve FDT_ERR_...
 388  */
 389 int fdtdec_get_chosen_node(const void *blob, const char *name);
 390
 391 /*
 392  * Get the name for a compatible ID
 393  *
 394  * @param id            Compatible ID to look for
 395  * @return compatible string for that id
 396  */
 397 const char *fdtdec_get_compatible(enum fdt_compat_id id);
 398
 399 /* Look up a phandle and follow it to its node. Then return the offset
 400  * of that node.
 401  *
 402  * @param blob          FDT blob
 403  * @param node          node to examine
 404  * @param prop_name     name of property to find
 405  * @return node offset if found, -ve error code on error
 406  */
 407 int fdtdec_lookup_phandle(const void *blob, int node, const char *prop_name);
 408
 409 /**
 410  * Look up a property in a node and return its contents in an integer
 411  * array of given length. The property must have at least enough data for
 412  * the array (4*count bytes). It may have more, but this will be ignored.
 413  *
 414  * @param blob          FDT blob
 415  * @param node          node to examine
 416  * @param prop_name     name of property to find
 417  * @param array         array to fill with data
 418  * @param count         number of array elements
 419  * @return 0 if ok, or -FDT_ERR_NOTFOUND if the property is not found,
 420  *              or -FDT_ERR_BADLAYOUT if not enough data
 421  */
 422 int fdtdec_get_int_array(const void *blob, int node, const char *prop_name,
 423                 u32 *array, int count);
 424
 425 /**
 426  * Look up a property in a node and return a pointer to its contents as a
 427  * unsigned int array of given length. The property must have at least enough
 428  * data for the array ('count' cells). It may have more, but this will be
 429  * ignored. The data is not copied.
 430  *
 431  * Note that you must access elements of the array with fdt32_to_cpu(),
 432  * since the elements will be big endian even on a little endian machine.
 433  *
 434  * @param blob          FDT blob
 435  * @param node          node to examine
 436  * @param prop_name     name of property to find
 437  * @param count         number of array elements
 438  * @return pointer to array if found, or NULL if the property is not
 439  *              found or there is not enough data
 440  */
 441 const u32 *fdtdec_locate_array(const void *blob, int node,
 442                                const char *prop_name, int count);
 443
 444 /**
 445  * Look up a boolean property in a node and return it.
 446  *
 447  * A boolean properly is true if present in the device tree and false if not
 448  * present, regardless of its value.
 449  *
 450  * @param blob  FDT blob
 451  * @param node  node to examine
 452  * @param prop_name     name of property to find
 453  * @return 1 if the properly is present; 0 if it isn't present
 454  */
 455 int fdtdec_get_bool(const void *blob, int node, const char *prop_name);
 456
 457 /**
 458  * Decode a single GPIOs from an FDT.
 459  *
 460  * If the property is not found, then the GPIO structure will still be
 461  * initialised, with gpio set to FDT_GPIO_NONE. This makes it easy to
 462  * provide optional GPIOs.
 463  *
 464  * @param blob          FDT blob to use
 465  * @param node          Node to look at
 466  * @param prop_name     Node property name
 467  * @param gpio          gpio elements to fill from FDT
 468  * @return 0 if ok, -FDT_ERR_NOTFOUND if the property is missing.
 469  */
 470 int fdtdec_decode_gpio(const void *blob, int node, const char *prop_name,
 471                 struct fdt_gpio_state *gpio);
 472
 473 /**
 474  * Decode a list of GPIOs from an FDT. This creates a list of GPIOs with no
 475  * terminating item.
 476  *
 477  * @param blob         FDT blob to use
 478  * @param node         Node to look at
 479  * @param prop_name    Node property name
 480  * @param gpio         Array of gpio elements to fill from FDT. This will be
 481  *                     untouched if either 0 or an error is returned
 482  * @param max_count    Maximum number of elements allowed
 483  * @return number of GPIOs read if ok, -FDT_ERR_BADLAYOUT if max_count would
 484  * be exceeded, or -FDT_ERR_NOTFOUND if the property is missing.
 485  */
 486 int fdtdec_decode_gpios(const void *blob, int node, const char *prop_name,
 487                 struct fdt_gpio_state *gpio, int max_count);
 488
 489 /**
 490  * Set up a GPIO pin according to the provided gpio information. At present this
 491  * just requests the GPIO.
 492  *
 493  * If the gpio is FDT_GPIO_NONE, no action is taken. This makes it easy to
 494  * deal with optional GPIOs.
 495  *
 496  * @param gpio          GPIO info to use for set up
 497  * @return 0 if all ok or gpio was FDT_GPIO_NONE; -1 on error
 498  */
 499 int fdtdec_setup_gpio(struct fdt_gpio_state *gpio);
 500
 501 /**
 502  * Look in the FDT for a config item with the given name and return its value
 503  * as a 32-bit integer. The property must have at least 4 bytes of data. The
 504  * value of the first cell is returned.
 505  *
 506  * @param blob          FDT blob to use
 507  * @param prop_name     Node property name
 508  * @param default_val   default value to return if the property is not found
 509  * @return integer value, if found, or default_val if not
 510  */
 511 int fdtdec_get_config_int(const void *blob, const char *prop_name,
 512                 int default_val);
 513
 514 /**
 515  * Look in the FDT for a config item with the given name
 516  * and return whether it exists.
 517  *
 518  * @param blob          FDT blob
 519  * @param prop_name     property name to look up
 520  * @return 1, if it exists, or 0 if not
 521  */
 522 int fdtdec_get_config_bool(const void *blob, const char *prop_name);
 523
 524 /**
 525  * Look in the FDT for a config item with the given name and return its value
 526  * as a string.
 527  *
 528  * @param blob          FDT blob
 529  * @param prop_name     property name to look up
 530  * @returns property string, NULL on error.
 531  */
 532 char *fdtdec_get_config_string(const void *blob, const char *prop_name);
 533
 534 /*
 535  * Look up a property in a node and return its contents in a byte
 536  * array of given length. The property must have at least enough data for
 537  * the array (count bytes). It may have more, but this will be ignored.
 538  *
 539  * @param blob          FDT blob
 540  * @param node          node to examine
 541  * @param prop_name     name of property to find
 542  * @param array         array to fill with data
 543  * @param count         number of array elements
 544  * @return 0 if ok, or -FDT_ERR_MISSING if the property is not found,
 545  *              or -FDT_ERR_BADLAYOUT if not enough data
 546  */
 547 int fdtdec_get_byte_array(const void *blob, int node, const char *prop_name,
 548                 u8 *array, int count);
 549
 550 /**
 551  * Look up a property in a node and return a pointer to its contents as a
 552  * byte array of given length. The property must have at least enough data
 553  * for the array (count bytes). It may have more, but this will be ignored.
 554  * The data is not copied.
 555  *
 556  * @param blob          FDT blob
 557  * @param node          node to examine
 558  * @param prop_name     name of property to find
 559  * @param count         number of array elements
 560  * @return pointer to byte array if found, or NULL if the property is not
 561  *              found or there is not enough data
 562  */
 563 const u8 *fdtdec_locate_byte_array(const void *blob, int node,
 564                              const char *prop_name, int count);
 565
 566 /**
 567  * Look up a property in a node which contains a memory region address and
 568  * size. Then return a pointer to this address.
 569  *
 570  * The property must hold one address with a length. This is only tested on
 571  * 32-bit machines.
 572  *
 573  * @param blob          FDT blob
 574  * @param node          node to examine
 575  * @param prop_name     name of property to find
 576  * @param ptrp          returns pointer to region, or NULL if no address
 577  * @param size          returns size of region
 578  * @return 0 if ok, -1 on error (propery not found)
 579  */
 580 int fdtdec_decode_region(const void *blob, int node,
 581                 const char *prop_name, void **ptrp, size_t *size);
 582
 583 /* A flash map entry, containing an offset and length */
 584 struct fmap_entry {
 585         uint32_t offset;
 586         uint32_t length;
 587 };
 588
 589 /**
 590  * Read a flash entry from the fdt
 591  *
 592  * @param blob          FDT blob
 593  * @param node          Offset of node to read
 594  * @param name          Name of node being read
 595  * @param entry         Place to put offset and size of this node
 596  * @return 0 if ok, -ve on error
 597  */
 598 int fdtdec_read_fmap_entry(const void *blob, int node, const char *name,
 599                            struct fmap_entry *entry);
 600 #endif