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_TEGRA20_I2C, /* Tegra20 i2c */ 66 COMPAT_NVIDIA_TEGRA20_DVC, /* Tegra20 dvc (really just i2c) */ 67 COMPAT_NVIDIA_TEGRA20_EMC, /* Tegra20 memory controller */ 68 COMPAT_NVIDIA_TEGRA20_EMC_TABLE, /* Tegra20 memory timing table */ 69 COMPAT_NVIDIA_TEGRA20_KBC, /* Tegra20 Keyboard */ 70 COMPAT_NVIDIA_TEGRA20_NAND, /* Tegra2 NAND controller */ 71 COMPAT_NVIDIA_TEGRA20_PWM, /* Tegra 2 PWM controller */ 72 COMPAT_NVIDIA_TEGRA20_DC, /* Tegra 2 Display controller */ 73 COMPAT_SMSC_LAN9215, /* SMSC 10/100 Ethernet LAN9215 */ 74 COMPAT_SAMSUNG_EXYNOS5_SROMC, /* Exynos5 SROMC */ 75 COMPAT_SAMSUNG_S3C2440_I2C, /* Exynos I2C Controller */ 76 COMPAT_SAMSUNG_EXYNOS5_SOUND, /* Exynos Sound */ 77 COMPAT_WOLFSON_WM8994_CODEC, /* Wolfson WM8994 Sound Codec */ 78 79 COMPAT_COUNT, 80 }; 81 82 /* GPIOs are numbered from 0 */ 83 enum { 84 FDT_GPIO_NONE = -1U, /* an invalid GPIO used to end our list */ 85 86 FDT_GPIO_ACTIVE_LOW = 1 << 0, /* input is active low (else high) */ 87 }; 88 89 /* This is the state of a GPIO pin as defined by the fdt */ 90 struct fdt_gpio_state { 91 const char *name; /* name of the fdt property defining this */ 92 uint gpio; /* GPIO number, or FDT_GPIO_NONE if none */ 93 u8 flags; /* FDT_GPIO_... flags */ 94 }; 95 96 /* This tells us whether a fdt_gpio_state record is valid or not */ 97 #define fdt_gpio_isvalid(x) ((x)->gpio != FDT_GPIO_NONE) 98 99 /** 100 * Read the GPIO taking into account the polarity of the pin. 101 * 102 * @param gpio pointer to the decoded gpio 103 * @return value of the gpio if successful, < 0 if unsuccessful 104 */ 105 int fdtdec_get_gpio(struct fdt_gpio_state *gpio); 106 107 /** 108 * Write the GPIO taking into account the polarity of the pin. 109 * 110 * @param gpio pointer to the decoded gpio 111 * @return 0 if successful 112 */ 113 int fdtdec_set_gpio(struct fdt_gpio_state *gpio, int val); 114 115 /** 116 * Find the next numbered alias for a peripheral. This is used to enumerate 117 * all the peripherals of a certain type. 118 * 119 * Do the first call with *upto = 0. Assuming /aliases/<name>0 exists then 120 * this function will return a pointer to the node the alias points to, and 121 * then update *upto to 1. Next time you call this function, the next node 122 * will be returned. 123 * 124 * All nodes returned will match the compatible ID, as it is assumed that 125 * all peripherals use the same driver. 126 * 127 * @param blob FDT blob to use 128 * @param name Root name of alias to search for 129 * @param id Compatible ID to look for 130 * @return offset of next compatible node, or -FDT_ERR_NOTFOUND if no more 131 */ 132 int fdtdec_next_alias(const void *blob, const char *name, 133 enum fdt_compat_id id, int *upto); 134 135 /** 136 * Find the compatible ID for a given node. 137 * 138 * Generally each node has at least one compatible string attached to it. 139 * This function looks through our list of known compatible strings and 140 * returns the corresponding ID which matches the compatible string. 141 * 142 * @param blob FDT blob to use 143 * @param node Node containing compatible string to find 144 * @return compatible ID, or COMPAT_UNKNOWN if we cannot find a match 145 */ 146 enum fdt_compat_id fdtdec_lookup(const void *blob, int node); 147 148 /** 149 * Find the next compatible node for a peripheral. 150 * 151 * Do the first call with node = 0. This function will return a pointer to 152 * the next compatible node. Next time you call this function, pass the 153 * value returned, and the next node will be provided. 154 * 155 * @param blob FDT blob to use 156 * @param node Start node for search 157 * @param id Compatible ID to look for (enum fdt_compat_id) 158 * @return offset of next compatible node, or -FDT_ERR_NOTFOUND if no more 159 */ 160 int fdtdec_next_compatible(const void *blob, int node, 161 enum fdt_compat_id id); 162 163 /** 164 * Find the next compatible subnode for a peripheral. 165 * 166 * Do the first call with node set to the parent and depth = 0. This 167 * function will return the offset of the next compatible node. Next time 168 * you call this function, pass the node value returned last time, with 169 * depth unchanged, and the next node will be provided. 170 * 171 * @param blob FDT blob to use 172 * @param node Start node for search 173 * @param id Compatible ID to look for (enum fdt_compat_id) 174 * @param depthp Current depth (set to 0 before first call) 175 * @return offset of next compatible node, or -FDT_ERR_NOTFOUND if no more 176 */ 177 int fdtdec_next_compatible_subnode(const void *blob, int node, 178 enum fdt_compat_id id, int *depthp); 179 180 /** 181 * Look up an address property in a node and return it as an address. 182 * The property must hold either one address with no trailing data or 183 * one address with a length. This is only tested on 32-bit machines. 184 * 185 * @param blob FDT blob 186 * @param node node to examine 187 * @param prop_name name of property to find 188 * @return address, if found, or FDT_ADDR_T_NONE if not 189 */ 190 fdt_addr_t fdtdec_get_addr(const void *blob, int node, 191 const char *prop_name); 192 193 /** 194 * Look up a 32-bit integer property in a node and return it. The property 195 * must have at least 4 bytes of data. The value of the first cell is 196 * returned. 197 * 198 * @param blob FDT blob 199 * @param node node to examine 200 * @param prop_name name of property to find 201 * @param default_val default value to return if the property is not found 202 * @return integer value, if found, or default_val if not 203 */ 204 s32 fdtdec_get_int(const void *blob, int node, const char *prop_name, 205 s32 default_val); 206 207 /** 208 * Look up a 64-bit integer property in a node and return it. The property 209 * must have at least 8 bytes of data (2 cells). The first two cells are 210 * concatenated to form a 8 bytes value, where the first cell is top half and 211 * the second cell is bottom half. 212 * 213 * @param blob FDT blob 214 * @param node node to examine 215 * @param prop_name name of property to find 216 * @param default_val default value to return if the property is not found 217 * @return integer value, if found, or default_val if not 218 */ 219 uint64_t fdtdec_get_uint64(const void *blob, int node, const char *prop_name, 220 uint64_t default_val); 221 222 /** 223 * Checks whether a node is enabled. 224 * This looks for a 'status' property. If this exists, then returns 1 if 225 * the status is 'ok' and 0 otherwise. If there is no status property, 226 * it returns 1 on the assumption that anything mentioned should be enabled 227 * by default. 228 * 229 * @param blob FDT blob 230 * @param node node to examine 231 * @return integer value 0 (not enabled) or 1 (enabled) 232 */ 233 int fdtdec_get_is_enabled(const void *blob, int node); 234 235 /** 236 * Make sure we have a valid fdt available to control U-Boot. 237 * 238 * If not, a message is printed to the console if the console is ready. 239 * 240 * @return 0 if all ok, -1 if not 241 */ 242 int fdtdec_prepare_fdt(void); 243 244 /** 245 * Checks that we have a valid fdt available to control U-Boot. 246 247 * However, if not then for the moment nothing is done, since this function 248 * is called too early to panic(). 249 * 250 * @returns 0 251 */ 252 int fdtdec_check_fdt(void); 253 254 /** 255 * Find the nodes for a peripheral and return a list of them in the correct 256 * order. This is used to enumerate all the peripherals of a certain type. 257 * 258 * To use this, optionally set up a /aliases node with alias properties for 259 * a peripheral. For example, for usb you could have: 260 * 261 * aliases { 262 * usb0 = "/ehci@c5008000"; 263 * usb1 = "/ehci@c5000000"; 264 * }; 265 * 266 * Pass "usb" as the name to this function and will return a list of two 267 * nodes offsets: /ehci@c5008000 and ehci@c5000000. 268 * 269 * All nodes returned will match the compatible ID, as it is assumed that 270 * all peripherals use the same driver. 271 * 272 * If no alias node is found, then the node list will be returned in the 273 * order found in the fdt. If the aliases mention a node which doesn't 274 * exist, then this will be ignored. If nodes are found with no aliases, 275 * they will be added in any order. 276 * 277 * If there is a gap in the aliases, then this function return a 0 node at 278 * that position. The return value will also count these gaps. 279 * 280 * This function checks node properties and will not return nodes which are 281 * marked disabled (status = "disabled"). 282 * 283 * @param blob FDT blob to use 284 * @param name Root name of alias to search for 285 * @param id Compatible ID to look for 286 * @param node_list Place to put list of found nodes 287 * @param maxcount Maximum number of nodes to find 288 * @return number of nodes found on success, FTD_ERR_... on error 289 */ 290 int fdtdec_find_aliases_for_id(const void *blob, const char *name, 291 enum fdt_compat_id id, int *node_list, int maxcount); 292 293 /* 294 * This function is similar to fdtdec_find_aliases_for_id() except that it 295 * adds to the node_list that is passed in. Any 0 elements are considered 296 * available for allocation - others are considered already used and are 297 * skipped. 298 * 299 * You can use this by calling fdtdec_find_aliases_for_id() with an 300 * uninitialised array, then setting the elements that are returned to -1, 301 * say, then calling this function, perhaps with a different compat id. 302 * Any elements you get back that are >0 are new nodes added by the call 303 * to this function. 304 * 305 * Note that if you have some nodes with aliases and some without, you are 306 * sailing close to the wind. The call to fdtdec_find_aliases_for_id() with 307 * one compat_id may fill in positions for which you have aliases defined 308 * for another compat_id. When you later call *this* function with the second 309 * compat_id, the alias positions may already be used. A debug warning may 310 * be generated in this case, but it is safest to define aliases for all 311 * nodes when you care about the ordering. 312 */ 313 int fdtdec_add_aliases_for_id(const void *blob, const char *name, 314 enum fdt_compat_id id, int *node_list, int maxcount); 315 316 /* 317 * Get the name for a compatible ID 318 * 319 * @param id Compatible ID to look for 320 * @return compatible string for that id 321 */ 322 const char *fdtdec_get_compatible(enum fdt_compat_id id); 323 324 /* Look up a phandle and follow it to its node. Then return the offset 325 * of that node. 326 * 327 * @param blob FDT blob 328 * @param node node to examine 329 * @param prop_name name of property to find 330 * @return node offset if found, -ve error code on error 331 */ 332 int fdtdec_lookup_phandle(const void *blob, int node, const char *prop_name); 333 334 /** 335 * Look up a property in a node and return its contents in an integer 336 * array of given length. The property must have at least enough data for 337 * the array (4*count bytes). It may have more, but this will be ignored. 338 * 339 * @param blob FDT blob 340 * @param node node to examine 341 * @param prop_name name of property to find 342 * @param array array to fill with data 343 * @param count number of array elements 344 * @return 0 if ok, or -FDT_ERR_NOTFOUND if the property is not found, 345 * or -FDT_ERR_BADLAYOUT if not enough data 346 */ 347 int fdtdec_get_int_array(const void *blob, int node, const char *prop_name, 348 u32 *array, int count); 349 350 /** 351 * Look up a property in a node and return a pointer to its contents as a 352 * unsigned int array of given length. The property must have at least enough 353 * data for the array ('count' cells). It may have more, but this will be 354 * ignored. The data is not copied. 355 * 356 * Note that you must access elements of the array with fdt32_to_cpu(), 357 * since the elements will be big endian even on a little endian machine. 358 * 359 * @param blob FDT blob 360 * @param node node to examine 361 * @param prop_name name of property to find 362 * @param count number of array elements 363 * @return pointer to array if found, or NULL if the property is not 364 * found or there is not enough data 365 */ 366 const u32 *fdtdec_locate_array(const void *blob, int node, 367 const char *prop_name, int count); 368 369 /** 370 * Look up a boolean property in a node and return it. 371 * 372 * A boolean properly is true if present in the device tree and false if not 373 * present, regardless of its value. 374 * 375 * @param blob FDT blob 376 * @param node node to examine 377 * @param prop_name name of property to find 378 * @return 1 if the properly is present; 0 if it isn't present 379 */ 380 int fdtdec_get_bool(const void *blob, int node, const char *prop_name); 381 382 /** 383 * Decode a single GPIOs from an FDT. 384 * 385 * If the property is not found, then the GPIO structure will still be 386 * initialised, with gpio set to FDT_GPIO_NONE. This makes it easy to 387 * provide optional GPIOs. 388 * 389 * @param blob FDT blob to use 390 * @param node Node to look at 391 * @param prop_name Node property name 392 * @param gpio gpio elements to fill from FDT 393 * @return 0 if ok, -FDT_ERR_NOTFOUND if the property is missing. 394 */ 395 int fdtdec_decode_gpio(const void *blob, int node, const char *prop_name, 396 struct fdt_gpio_state *gpio); 397 398 /** 399 * Decode a list of GPIOs from an FDT. This creates a list of GPIOs with no 400 * terminating item. 401 * 402 * @param blob FDT blob to use 403 * @param node Node to look at 404 * @param prop_name Node property name 405 * @param gpio Array of gpio elements to fill from FDT. This will be 406 * untouched if either 0 or an error is returned 407 * @param max_count Maximum number of elements allowed 408 * @return number of GPIOs read if ok, -FDT_ERR_BADLAYOUT if max_count would 409 * be exceeded, or -FDT_ERR_NOTFOUND if the property is missing. 410 */ 411 int fdtdec_decode_gpios(const void *blob, int node, const char *prop_name, 412 struct fdt_gpio_state *gpio, int max_count); 413 414 /** 415 * Set up a GPIO pin according to the provided gpio information. At present this 416 * just requests the GPIO. 417 * 418 * If the gpio is FDT_GPIO_NONE, no action is taken. This makes it easy to 419 * deal with optional GPIOs. 420 * 421 * @param gpio GPIO info to use for set up 422 * @return 0 if all ok or gpio was FDT_GPIO_NONE; -1 on error 423 */ 424 int fdtdec_setup_gpio(struct fdt_gpio_state *gpio); 425 426 /** 427 * Look in the FDT for a config item with the given name and return its value 428 * as a 32-bit integer. The property must have at least 4 bytes of data. The 429 * value of the first cell is returned. 430 * 431 * @param blob FDT blob to use 432 * @param prop_name Node property name 433 * @param default_val default value to return if the property is not found 434 * @return integer value, if found, or default_val if not 435 */ 436 int fdtdec_get_config_int(const void *blob, const char *prop_name, 437 int default_val); 438 439 /** 440 * Look in the FDT for a config item with the given name 441 * and return whether it exists. 442 * 443 * @param blob FDT blob 444 * @param prop_name property name to look up 445 * @return 1, if it exists, or 0 if not 446 */ 447 int fdtdec_get_config_bool(const void *blob, const char *prop_name); 448 449 /** 450 * Look in the FDT for a config item with the given name and return its value 451 * as a string. 452 * 453 * @param blob FDT blob 454 * @param prop_name property name to look up 455 * @returns property string, NULL on error. 456 */ 457 char *fdtdec_get_config_string(const void *blob, const char *prop_name); 458 459 /* 460 * Look up a property in a node and return its contents in a byte 461 * array of given length. The property must have at least enough data for 462 * the array (count bytes). It may have more, but this will be ignored. 463 * 464 * @param blob FDT blob 465 * @param node node to examine 466 * @param prop_name name of property to find 467 * @param array array to fill with data 468 * @param count number of array elements 469 * @return 0 if ok, or -FDT_ERR_MISSING if the property is not found, 470 * or -FDT_ERR_BADLAYOUT if not enough data 471 */ 472 int fdtdec_get_byte_array(const void *blob, int node, const char *prop_name, 473 u8 *array, int count); 474 475 /** 476 * Look up a property in a node and return a pointer to its contents as a 477 * byte array of given length. The property must have at least enough data 478 * for the array (count bytes). It may have more, but this will be ignored. 479 * The data is not copied. 480 * 481 * @param blob FDT blob 482 * @param node node to examine 483 * @param prop_name name of property to find 484 * @param count number of array elements 485 * @return pointer to byte array if found, or NULL if the property is not 486 * found or there is not enough data 487 */ 488 const u8 *fdtdec_locate_byte_array(const void *blob, int node, 489 const char *prop_name, int count); 490 491 /** 492 * Look up a property in a node which contains a memory region address and 493 * size. Then return a pointer to this address. 494 * 495 * The property must hold one address with a length. This is only tested on 496 * 32-bit machines. 497 * 498 * @param blob FDT blob 499 * @param node node to examine 500 * @param prop_name name of property to find 501 * @param ptrp returns pointer to region, or NULL if no address 502 * @param size returns size of region 503 * @return 0 if ok, -1 on error (propery not found) 504 */ 505 int fdtdec_decode_region(const void *blob, int node, 506 const char *prop_name, void **ptrp, size_t *size); 507 #endif 508