include/fdtdec.h

   1 /*
   2  * Copyright (c) 2011 The Chromium OS Authors.
   3  * See file CREDITS for list of people who contributed to this
   4  * project.
   5  *
   6  * This program is free software; you can redistribute it and/or
   7  * modify it under the terms of the GNU General Public License as
   8  * published by the Free Software Foundation; either version 2 of
   9  * the License, or (at your option) any later version.
  10  *
  11  * This program is distributed in the hope that it will be useful,
  12  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  13  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  14  * GNU General Public License for more details.
  15  *
  16  * You should have received a copy of the GNU General Public License
  17  * along with this program; if not, write to the Free Software
  18  * Foundation, Inc., 59 Temple Place, Suite 330, Boston,
  19  * MA 02111-1307 USA
  20  */
  21
  22 #ifndef __fdtdec_h
  23 #define __fdtdec_h
  24
  25 /*
  26  * This file contains convenience functions for decoding useful and
  27  * enlightening information from FDTs. It is intended to be used by device
  28  * drivers and board-specific code within U-Boot. It aims to reduce the
  29  * amount of FDT munging required within U-Boot itself, so that driver code
  30  * changes to support FDT are minimized.
  31  */
  32
  33 #include <libfdt.h>
  34
  35 /*
  36  * A typedef for a physical address. Note that fdt data is always big
  37  * endian even on a litle endian machine.
  38  */
  39 #ifdef CONFIG_PHYS_64BIT
  40 typedef u64 fdt_addr_t;
  41 #define FDT_ADDR_T_NONE (-1ULL)
  42 #define fdt_addr_to_cpu(reg) be64_to_cpu(reg)
  43 #define fdt_size_to_cpu(reg) be64_to_cpu(reg)
  44 #else
  45 typedef u32 fdt_addr_t;
  46 #define FDT_ADDR_T_NONE (-1U)
  47 #define fdt_addr_to_cpu(reg) be32_to_cpu(reg)
  48 #define fdt_size_to_cpu(reg) be32_to_cpu(reg)
  49 #endif
  50
  51 /* Information obtained about memory from the FDT */
  52 struct fdt_memory {
  53         fdt_addr_t start;
  54         fdt_addr_t end;
  55 };
  56
  57 /**
  58  * Compat types that we know about and for which we might have drivers.
  59  * Each is named COMPAT_<dir>_<filename> where <dir> is the directory
  60  * within drivers.
  61  */
  62 enum fdt_compat_id {
  63         COMPAT_UNKNOWN,
  64         COMPAT_NVIDIA_TEGRA20_USB,      /* Tegra20 USB port */
  65         COMPAT_NVIDIA_TEGRA114_I2C,     /* Tegra114 I2C w/single clock source */
  66         COMPAT_NVIDIA_TEGRA20_I2C,      /* Tegra20 i2c */
  67         COMPAT_NVIDIA_TEGRA20_DVC,      /* Tegra20 dvc (really just i2c) */
  68         COMPAT_NVIDIA_TEGRA20_EMC,      /* Tegra20 memory controller */
  69         COMPAT_NVIDIA_TEGRA20_EMC_TABLE, /* Tegra20 memory timing table */
  70         COMPAT_NVIDIA_TEGRA20_KBC,      /* Tegra20 Keyboard */
  71         COMPAT_NVIDIA_TEGRA20_NAND,     /* Tegra2 NAND controller */
  72         COMPAT_NVIDIA_TEGRA20_PWM,      /* Tegra 2 PWM controller */
  73         COMPAT_NVIDIA_TEGRA20_DC,       /* Tegra 2 Display controller */
  74         COMPAT_NVIDIA_TEGRA30_SDMMC,    /* Tegra30 SDMMC controller */
  75         COMPAT_NVIDIA_TEGRA20_SDMMC,    /* Tegra20 SDMMC controller */
  76         COMPAT_NVIDIA_TEGRA20_SFLASH,   /* Tegra 2 SPI flash controller */
  77         COMPAT_NVIDIA_TEGRA20_SLINK,    /* Tegra 2 SPI SLINK controller */
  78         COMPAT_NVIDIA_TEGRA114_SPI,     /* Tegra 114 SPI controller */
  79         COMPAT_SMSC_LAN9215,            /* SMSC 10/100 Ethernet LAN9215 */
  80         COMPAT_SAMSUNG_EXYNOS5_SROMC,   /* Exynos5 SROMC */
  81         COMPAT_SAMSUNG_S3C2440_I2C,     /* Exynos I2C Controller */
  82         COMPAT_SAMSUNG_EXYNOS5_SOUND,   /* Exynos Sound */
  83         COMPAT_WOLFSON_WM8994_CODEC,    /* Wolfson WM8994 Sound Codec */
  84         COMPAT_SAMSUNG_EXYNOS_SPI,      /* Exynos SPI */
  85         COMPAT_SAMSUNG_EXYNOS_EHCI,     /* Exynos EHCI controller */
  86         COMPAT_SAMSUNG_EXYNOS_USB_PHY,  /* Exynos phy controller for usb2.0 */
  87         COMPAT_MAXIM_MAX77686_PMIC,     /* MAX77686 PMIC */
  88
  89         COMPAT_COUNT,
  90 };
  91
  92 /* GPIOs are numbered from 0 */
  93 enum {
  94         FDT_GPIO_NONE = -1U,    /* an invalid GPIO used to end our list */
  95
  96         FDT_GPIO_ACTIVE_LOW = 1 << 0,   /* input is active low (else high) */
  97 };
  98
  99 /* This is the state of a GPIO pin as defined by the fdt */
 100 struct fdt_gpio_state {
 101         const char *name;       /* name of the fdt property defining this */
 102         uint gpio;              /* GPIO number, or FDT_GPIO_NONE if none */
 103         u8 flags;               /* FDT_GPIO_... flags */
 104 };
 105
 106 /* This tells us whether a fdt_gpio_state record is valid or not */
 107 #define fdt_gpio_isvalid(x) ((x)->gpio != FDT_GPIO_NONE)
 108
 109 /**
 110  * Read the GPIO taking into account the polarity of the pin.
 111  *
 112  * @param gpio          pointer to the decoded gpio
 113  * @return value of the gpio if successful, < 0 if unsuccessful
 114  */
 115 int fdtdec_get_gpio(struct fdt_gpio_state *gpio);
 116
 117 /**
 118  * Write the GPIO taking into account the polarity of the pin.
 119  *
 120  * @param gpio          pointer to the decoded gpio
 121  * @return 0 if successful
 122  */
 123 int fdtdec_set_gpio(struct fdt_gpio_state *gpio, int val);
 124
 125 /**
 126  * Find the next numbered alias for a peripheral. This is used to enumerate
 127  * all the peripherals of a certain type.
 128  *
 129  * Do the first call with *upto = 0. Assuming /aliases/<name>0 exists then
 130  * this function will return a pointer to the node the alias points to, and
 131  * then update *upto to 1. Next time you call this function, the next node
 132  * will be returned.
 133  *
 134  * All nodes returned will match the compatible ID, as it is assumed that
 135  * all peripherals use the same driver.
 136  *
 137  * @param blob          FDT blob to use
 138  * @param name          Root name of alias to search for
 139  * @param id            Compatible ID to look for
 140  * @return offset of next compatible node, or -FDT_ERR_NOTFOUND if no more
 141  */
 142 int fdtdec_next_alias(const void *blob, const char *name,
 143                 enum fdt_compat_id id, int *upto);
 144
 145 /**
 146  * Find the compatible ID for a given node.
 147  *
 148  * Generally each node has at least one compatible string attached to it.
 149  * This function looks through our list of known compatible strings and
 150  * returns the corresponding ID which matches the compatible string.
 151  *
 152  * @param blob          FDT blob to use
 153  * @param node          Node containing compatible string to find
 154  * @return compatible ID, or COMPAT_UNKNOWN if we cannot find a match
 155  */
 156 enum fdt_compat_id fdtdec_lookup(const void *blob, int node);
 157
 158 /**
 159  * Find the next compatible node for a peripheral.
 160  *
 161  * Do the first call with node = 0. This function will return a pointer to
 162  * the next compatible node. Next time you call this function, pass the
 163  * value returned, and the next node will be provided.
 164  *
 165  * @param blob          FDT blob to use
 166  * @param node          Start node for search
 167  * @param id            Compatible ID to look for (enum fdt_compat_id)
 168  * @return offset of next compatible node, or -FDT_ERR_NOTFOUND if no more
 169  */
 170 int fdtdec_next_compatible(const void *blob, int node,
 171                 enum fdt_compat_id id);
 172
 173 /**
 174  * Find the next compatible subnode for a peripheral.
 175  *
 176  * Do the first call with node set to the parent and depth = 0. This
 177  * function will return the offset of the next compatible node. Next time
 178  * you call this function, pass the node value returned last time, with
 179  * depth unchanged, and the next node will be provided.
 180  *
 181  * @param blob          FDT blob to use
 182  * @param node          Start node for search
 183  * @param id            Compatible ID to look for (enum fdt_compat_id)
 184  * @param depthp        Current depth (set to 0 before first call)
 185  * @return offset of next compatible node, or -FDT_ERR_NOTFOUND if no more
 186  */
 187 int fdtdec_next_compatible_subnode(const void *blob, int node,
 188                 enum fdt_compat_id id, int *depthp);
 189
 190 /**
 191  * Look up an address property in a node and return it as an address.
 192  * The property must hold either one address with no trailing data or
 193  * one address with a length. This is only tested on 32-bit machines.
 194  *
 195  * @param blob  FDT blob
 196  * @param node  node to examine
 197  * @param prop_name     name of property to find
 198  * @return address, if found, or FDT_ADDR_T_NONE if not
 199  */
 200 fdt_addr_t fdtdec_get_addr(const void *blob, int node,
 201                 const char *prop_name);
 202
 203 /**
 204  * Look up a 32-bit integer property in a node and return it. The property
 205  * must have at least 4 bytes of data. The value of the first cell is
 206  * returned.
 207  *
 208  * @param blob  FDT blob
 209  * @param node  node to examine
 210  * @param prop_name     name of property to find
 211  * @param default_val   default value to return if the property is not found
 212  * @return integer value, if found, or default_val if not
 213  */
 214 s32 fdtdec_get_int(const void *blob, int node, const char *prop_name,
 215                 s32 default_val);
 216
 217 /**
 218  * Look up a 64-bit integer property in a node and return it. The property
 219  * must have at least 8 bytes of data (2 cells). The first two cells are
 220  * concatenated to form a 8 bytes value, where the first cell is top half and
 221  * the second cell is bottom half.
 222  *
 223  * @param blob  FDT blob
 224  * @param node  node to examine
 225  * @param prop_name     name of property to find
 226  * @param default_val   default value to return if the property is not found
 227  * @return integer value, if found, or default_val if not
 228  */
 229 uint64_t fdtdec_get_uint64(const void *blob, int node, const char *prop_name,
 230                 uint64_t default_val);
 231
 232 /**
 233  * Checks whether a node is enabled.
 234  * This looks for a 'status' property. If this exists, then returns 1 if
 235  * the status is 'ok' and 0 otherwise. If there is no status property,
 236  * it returns 1 on the assumption that anything mentioned should be enabled
 237  * by default.
 238  *
 239  * @param blob  FDT blob
 240  * @param node  node to examine
 241  * @return integer value 0 (not enabled) or 1 (enabled)
 242  */
 243 int fdtdec_get_is_enabled(const void *blob, int node);
 244
 245 /**
 246  * Make sure we have a valid fdt available to control U-Boot.
 247  *
 248  * If not, a message is printed to the console if the console is ready.
 249  *
 250  * @return 0 if all ok, -1 if not
 251  */
 252 int fdtdec_prepare_fdt(void);
 253
 254 /**
 255  * Checks that we have a valid fdt available to control U-Boot.
 256
 257  * However, if not then for the moment nothing is done, since this function
 258  * is called too early to panic().
 259  *
 260  * @returns 0
 261  */
 262 int fdtdec_check_fdt(void);
 263
 264 /**
 265  * Find the nodes for a peripheral and return a list of them in the correct
 266  * order. This is used to enumerate all the peripherals of a certain type.
 267  *
 268  * To use this, optionally set up a /aliases node with alias properties for
 269  * a peripheral. For example, for usb you could have:
 270  *
 271  * aliases {
 272  *              usb0 = "/ehci@c5008000";
 273  *              usb1 = "/ehci@c5000000";
 274  * };
 275  *
 276  * Pass "usb" as the name to this function and will return a list of two
 277  * nodes offsets: /ehci@c5008000 and ehci@c5000000.
 278  *
 279  * All nodes returned will match the compatible ID, as it is assumed that
 280  * all peripherals use the same driver.
 281  *
 282  * If no alias node is found, then the node list will be returned in the
 283  * order found in the fdt. If the aliases mention a node which doesn't
 284  * exist, then this will be ignored. If nodes are found with no aliases,
 285  * they will be added in any order.
 286  *
 287  * If there is a gap in the aliases, then this function return a 0 node at
 288  * that position. The return value will also count these gaps.
 289  *
 290  * This function checks node properties and will not return nodes which are
 291  * marked disabled (status = "disabled").
 292  *
 293  * @param blob          FDT blob to use
 294  * @param name          Root name of alias to search for
 295  * @param id            Compatible ID to look for
 296  * @param node_list     Place to put list of found nodes
 297  * @param maxcount      Maximum number of nodes to find
 298  * @return number of nodes found on success, FTD_ERR_... on error
 299  */
 300 int fdtdec_find_aliases_for_id(const void *blob, const char *name,
 301                         enum fdt_compat_id id, int *node_list, int maxcount);
 302
 303 /*
 304  * This function is similar to fdtdec_find_aliases_for_id() except that it
 305  * adds to the node_list that is passed in. Any 0 elements are considered
 306  * available for allocation - others are considered already used and are
 307  * skipped.
 308  *
 309  * You can use this by calling fdtdec_find_aliases_for_id() with an
 310  * uninitialised array, then setting the elements that are returned to -1,
 311  * say, then calling this function, perhaps with a different compat id.
 312  * Any elements you get back that are >0 are new nodes added by the call
 313  * to this function.
 314  *
 315  * Note that if you have some nodes with aliases and some without, you are
 316  * sailing close to the wind. The call to fdtdec_find_aliases_for_id() with
 317  * one compat_id may fill in positions for which you have aliases defined
 318  * for another compat_id. When you later call *this* function with the second
 319  * compat_id, the alias positions may already be used. A debug warning may
 320  * be generated in this case, but it is safest to define aliases for all
 321  * nodes when you care about the ordering.
 322  */
 323 int fdtdec_add_aliases_for_id(const void *blob, const char *name,
 324                         enum fdt_compat_id id, int *node_list, int maxcount);
 325
 326 /*
 327  * Get the name for a compatible ID
 328  *
 329  * @param id            Compatible ID to look for
 330  * @return compatible string for that id
 331  */
 332 const char *fdtdec_get_compatible(enum fdt_compat_id id);
 333
 334 /* Look up a phandle and follow it to its node. Then return the offset
 335  * of that node.
 336  *
 337  * @param blob          FDT blob
 338  * @param node          node to examine
 339  * @param prop_name     name of property to find
 340  * @return node offset if found, -ve error code on error
 341  */
 342 int fdtdec_lookup_phandle(const void *blob, int node, const char *prop_name);
 343
 344 /**
 345  * Look up a property in a node and return its contents in an integer
 346  * array of given length. The property must have at least enough data for
 347  * the array (4*count bytes). It may have more, but this will be ignored.
 348  *
 349  * @param blob          FDT blob
 350  * @param node          node to examine
 351  * @param prop_name     name of property to find
 352  * @param array         array to fill with data
 353  * @param count         number of array elements
 354  * @return 0 if ok, or -FDT_ERR_NOTFOUND if the property is not found,
 355  *              or -FDT_ERR_BADLAYOUT if not enough data
 356  */
 357 int fdtdec_get_int_array(const void *blob, int node, const char *prop_name,
 358                 u32 *array, int count);
 359
 360 /**
 361  * Look up a property in a node and return a pointer to its contents as a
 362  * unsigned int array of given length. The property must have at least enough
 363  * data for the array ('count' cells). It may have more, but this will be
 364  * ignored. The data is not copied.
 365  *
 366  * Note that you must access elements of the array with fdt32_to_cpu(),
 367  * since the elements will be big endian even on a little endian machine.
 368  *
 369  * @param blob          FDT blob
 370  * @param node          node to examine
 371  * @param prop_name     name of property to find
 372  * @param count         number of array elements
 373  * @return pointer to array if found, or NULL if the property is not
 374  *              found or there is not enough data
 375  */
 376 const u32 *fdtdec_locate_array(const void *blob, int node,
 377                                const char *prop_name, int count);
 378
 379 /**
 380  * Look up a boolean property in a node and return it.
 381  *
 382  * A boolean properly is true if present in the device tree and false if not
 383  * present, regardless of its value.
 384  *
 385  * @param blob  FDT blob
 386  * @param node  node to examine
 387  * @param prop_name     name of property to find
 388  * @return 1 if the properly is present; 0 if it isn't present
 389  */
 390 int fdtdec_get_bool(const void *blob, int node, const char *prop_name);
 391
 392 /**
 393  * Decode a single GPIOs from an FDT.
 394  *
 395  * If the property is not found, then the GPIO structure will still be
 396  * initialised, with gpio set to FDT_GPIO_NONE. This makes it easy to
 397  * provide optional GPIOs.
 398  *
 399  * @param blob          FDT blob to use
 400  * @param node          Node to look at
 401  * @param prop_name     Node property name
 402  * @param gpio          gpio elements to fill from FDT
 403  * @return 0 if ok, -FDT_ERR_NOTFOUND if the property is missing.
 404  */
 405 int fdtdec_decode_gpio(const void *blob, int node, const char *prop_name,
 406                 struct fdt_gpio_state *gpio);
 407
 408 /**
 409  * Decode a list of GPIOs from an FDT. This creates a list of GPIOs with no
 410  * terminating item.
 411  *
 412  * @param blob         FDT blob to use
 413  * @param node         Node to look at
 414  * @param prop_name    Node property name
 415  * @param gpio         Array of gpio elements to fill from FDT. This will be
 416  *                     untouched if either 0 or an error is returned
 417  * @param max_count    Maximum number of elements allowed
 418  * @return number of GPIOs read if ok, -FDT_ERR_BADLAYOUT if max_count would
 419  * be exceeded, or -FDT_ERR_NOTFOUND if the property is missing.
 420  */
 421 int fdtdec_decode_gpios(const void *blob, int node, const char *prop_name,
 422                 struct fdt_gpio_state *gpio, int max_count);
 423
 424 /**
 425  * Set up a GPIO pin according to the provided gpio information. At present this
 426  * just requests the GPIO.
 427  *
 428  * If the gpio is FDT_GPIO_NONE, no action is taken. This makes it easy to
 429  * deal with optional GPIOs.
 430  *
 431  * @param gpio          GPIO info to use for set up
 432  * @return 0 if all ok or gpio was FDT_GPIO_NONE; -1 on error
 433  */
 434 int fdtdec_setup_gpio(struct fdt_gpio_state *gpio);
 435
 436 /**
 437  * Look in the FDT for a config item with the given name and return its value
 438  * as a 32-bit integer. The property must have at least 4 bytes of data. The
 439  * value of the first cell is returned.
 440  *
 441  * @param blob          FDT blob to use
 442  * @param prop_name     Node property name
 443  * @param default_val   default value to return if the property is not found
 444  * @return integer value, if found, or default_val if not
 445  */
 446 int fdtdec_get_config_int(const void *blob, const char *prop_name,
 447                 int default_val);
 448
 449 /**
 450  * Look in the FDT for a config item with the given name
 451  * and return whether it exists.
 452  *
 453  * @param blob          FDT blob
 454  * @param prop_name     property name to look up
 455  * @return 1, if it exists, or 0 if not
 456  */
 457 int fdtdec_get_config_bool(const void *blob, const char *prop_name);
 458
 459 /**
 460  * Look in the FDT for a config item with the given name and return its value
 461  * as a string.
 462  *
 463  * @param blob          FDT blob
 464  * @param prop_name     property name to look up
 465  * @returns property string, NULL on error.
 466  */
 467 char *fdtdec_get_config_string(const void *blob, const char *prop_name);
 468
 469 /*
 470  * Look up a property in a node and return its contents in a byte
 471  * array of given length. The property must have at least enough data for
 472  * the array (count bytes). It may have more, but this will be ignored.
 473  *
 474  * @param blob          FDT blob
 475  * @param node          node to examine
 476  * @param prop_name     name of property to find
 477  * @param array         array to fill with data
 478  * @param count         number of array elements
 479  * @return 0 if ok, or -FDT_ERR_MISSING if the property is not found,
 480  *              or -FDT_ERR_BADLAYOUT if not enough data
 481  */
 482 int fdtdec_get_byte_array(const void *blob, int node, const char *prop_name,
 483                 u8 *array, int count);
 484
 485 /**
 486  * Look up a property in a node and return a pointer to its contents as a
 487  * byte array of given length. The property must have at least enough data
 488  * for the array (count bytes). It may have more, but this will be ignored.
 489  * The data is not copied.
 490  *
 491  * @param blob          FDT blob
 492  * @param node          node to examine
 493  * @param prop_name     name of property to find
 494  * @param count         number of array elements
 495  * @return pointer to byte array if found, or NULL if the property is not
 496  *              found or there is not enough data
 497  */
 498 const u8 *fdtdec_locate_byte_array(const void *blob, int node,
 499                              const char *prop_name, int count);
 500
 501 /**
 502  * Look up a property in a node which contains a memory region address and
 503  * size. Then return a pointer to this address.
 504  *
 505  * The property must hold one address with a length. This is only tested on
 506  * 32-bit machines.
 507  *
 508  * @param blob          FDT blob
 509  * @param node          node to examine
 510  * @param prop_name     name of property to find
 511  * @param ptrp          returns pointer to region, or NULL if no address
 512  * @param size          returns size of region
 513  * @return 0 if ok, -1 on error (propery not found)
 514  */
 515 int fdtdec_decode_region(const void *blob, int node,
 516                 const char *prop_name, void **ptrp, size_t *size);
 517 #endif