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 COMPAT_SAMSUNG_EXYNOS_SPI, /* Exynos SPI */ 79 80 COMPAT_COUNT, 81 }; 82 83 /* GPIOs are numbered from 0 */ 84 enum { 85 FDT_GPIO_NONE = -1U, /* an invalid GPIO used to end our list */ 86 87 FDT_GPIO_ACTIVE_LOW = 1 << 0, /* input is active low (else high) */ 88 }; 89 90 /* This is the state of a GPIO pin as defined by the fdt */ 91 struct fdt_gpio_state { 92 const char *name; /* name of the fdt property defining this */ 93 uint gpio; /* GPIO number, or FDT_GPIO_NONE if none */ 94 u8 flags; /* FDT_GPIO_... flags */ 95 }; 96 97 /* This tells us whether a fdt_gpio_state record is valid or not */ 98 #define fdt_gpio_isvalid(x) ((x)->gpio != FDT_GPIO_NONE) 99 100 /** 101 * Read the GPIO taking into account the polarity of the pin. 102 * 103 * @param gpio pointer to the decoded gpio 104 * @return value of the gpio if successful, < 0 if unsuccessful 105 */ 106 int fdtdec_get_gpio(struct fdt_gpio_state *gpio); 107 108 /** 109 * Write the GPIO taking into account the polarity of the pin. 110 * 111 * @param gpio pointer to the decoded gpio 112 * @return 0 if successful 113 */ 114 int fdtdec_set_gpio(struct fdt_gpio_state *gpio, int val); 115 116 /** 117 * Find the next numbered alias for a peripheral. This is used to enumerate 118 * all the peripherals of a certain type. 119 * 120 * Do the first call with *upto = 0. Assuming /aliases/<name>0 exists then 121 * this function will return a pointer to the node the alias points to, and 122 * then update *upto to 1. Next time you call this function, the next node 123 * will be returned. 124 * 125 * All nodes returned will match the compatible ID, as it is assumed that 126 * all peripherals use the same driver. 127 * 128 * @param blob FDT blob to use 129 * @param name Root name of alias to search for 130 * @param id Compatible ID to look for 131 * @return offset of next compatible node, or -FDT_ERR_NOTFOUND if no more 132 */ 133 int fdtdec_next_alias(const void *blob, const char *name, 134 enum fdt_compat_id id, int *upto); 135 136 /** 137 * Find the compatible ID for a given node. 138 * 139 * Generally each node has at least one compatible string attached to it. 140 * This function looks through our list of known compatible strings and 141 * returns the corresponding ID which matches the compatible string. 142 * 143 * @param blob FDT blob to use 144 * @param node Node containing compatible string to find 145 * @return compatible ID, or COMPAT_UNKNOWN if we cannot find a match 146 */ 147 enum fdt_compat_id fdtdec_lookup(const void *blob, int node); 148 149 /** 150 * Find the next compatible node for a peripheral. 151 * 152 * Do the first call with node = 0. This function will return a pointer to 153 * the next compatible node. Next time you call this function, pass the 154 * value returned, and the next node will be provided. 155 * 156 * @param blob FDT blob to use 157 * @param node Start node for search 158 * @param id Compatible ID to look for (enum fdt_compat_id) 159 * @return offset of next compatible node, or -FDT_ERR_NOTFOUND if no more 160 */ 161 int fdtdec_next_compatible(const void *blob, int node, 162 enum fdt_compat_id id); 163 164 /** 165 * Find the next compatible subnode for a peripheral. 166 * 167 * Do the first call with node set to the parent and depth = 0. This 168 * function will return the offset of the next compatible node. Next time 169 * you call this function, pass the node value returned last time, with 170 * depth unchanged, and the next node will be provided. 171 * 172 * @param blob FDT blob to use 173 * @param node Start node for search 174 * @param id Compatible ID to look for (enum fdt_compat_id) 175 * @param depthp Current depth (set to 0 before first call) 176 * @return offset of next compatible node, or -FDT_ERR_NOTFOUND if no more 177 */ 178 int fdtdec_next_compatible_subnode(const void *blob, int node, 179 enum fdt_compat_id id, int *depthp); 180 181 /** 182 * Look up an address property in a node and return it as an address. 183 * The property must hold either one address with no trailing data or 184 * one address with a length. This is only tested on 32-bit machines. 185 * 186 * @param blob FDT blob 187 * @param node node to examine 188 * @param prop_name name of property to find 189 * @return address, if found, or FDT_ADDR_T_NONE if not 190 */ 191 fdt_addr_t fdtdec_get_addr(const void *blob, int node, 192 const char *prop_name); 193 194 /** 195 * Look up a 32-bit integer property in a node and return it. The property 196 * must have at least 4 bytes of data. The value of the first cell is 197 * returned. 198 * 199 * @param blob FDT blob 200 * @param node node to examine 201 * @param prop_name name of property to find 202 * @param default_val default value to return if the property is not found 203 * @return integer value, if found, or default_val if not 204 */ 205 s32 fdtdec_get_int(const void *blob, int node, const char *prop_name, 206 s32 default_val); 207 208 /** 209 * Look up a 64-bit integer property in a node and return it. The property 210 * must have at least 8 bytes of data (2 cells). The first two cells are 211 * concatenated to form a 8 bytes value, where the first cell is top half and 212 * the second cell is bottom half. 213 * 214 * @param blob FDT blob 215 * @param node node to examine 216 * @param prop_name name of property to find 217 * @param default_val default value to return if the property is not found 218 * @return integer value, if found, or default_val if not 219 */ 220 uint64_t fdtdec_get_uint64(const void *blob, int node, const char *prop_name, 221 uint64_t default_val); 222 223 /** 224 * Checks whether a node is enabled. 225 * This looks for a 'status' property. If this exists, then returns 1 if 226 * the status is 'ok' and 0 otherwise. If there is no status property, 227 * it returns 1 on the assumption that anything mentioned should be enabled 228 * by default. 229 * 230 * @param blob FDT blob 231 * @param node node to examine 232 * @return integer value 0 (not enabled) or 1 (enabled) 233 */ 234 int fdtdec_get_is_enabled(const void *blob, int node); 235 236 /** 237 * Make sure we have a valid fdt available to control U-Boot. 238 * 239 * If not, a message is printed to the console if the console is ready. 240 * 241 * @return 0 if all ok, -1 if not 242 */ 243 int fdtdec_prepare_fdt(void); 244 245 /** 246 * Checks that we have a valid fdt available to control U-Boot. 247 248 * However, if not then for the moment nothing is done, since this function 249 * is called too early to panic(). 250 * 251 * @returns 0 252 */ 253 int fdtdec_check_fdt(void); 254 255 /** 256 * Find the nodes for a peripheral and return a list of them in the correct 257 * order. This is used to enumerate all the peripherals of a certain type. 258 * 259 * To use this, optionally set up a /aliases node with alias properties for 260 * a peripheral. For example, for usb you could have: 261 * 262 * aliases { 263 * usb0 = "/ehci@c5008000"; 264 * usb1 = "/ehci@c5000000"; 265 * }; 266 * 267 * Pass "usb" as the name to this function and will return a list of two 268 * nodes offsets: /ehci@c5008000 and ehci@c5000000. 269 * 270 * All nodes returned will match the compatible ID, as it is assumed that 271 * all peripherals use the same driver. 272 * 273 * If no alias node is found, then the node list will be returned in the 274 * order found in the fdt. If the aliases mention a node which doesn't 275 * exist, then this will be ignored. If nodes are found with no aliases, 276 * they will be added in any order. 277 * 278 * If there is a gap in the aliases, then this function return a 0 node at 279 * that position. The return value will also count these gaps. 280 * 281 * This function checks node properties and will not return nodes which are 282 * marked disabled (status = "disabled"). 283 * 284 * @param blob FDT blob to use 285 * @param name Root name of alias to search for 286 * @param id Compatible ID to look for 287 * @param node_list Place to put list of found nodes 288 * @param maxcount Maximum number of nodes to find 289 * @return number of nodes found on success, FTD_ERR_... on error 290 */ 291 int fdtdec_find_aliases_for_id(const void *blob, const char *name, 292 enum fdt_compat_id id, int *node_list, int maxcount); 293 294 /* 295 * This function is similar to fdtdec_find_aliases_for_id() except that it 296 * adds to the node_list that is passed in. Any 0 elements are considered 297 * available for allocation - others are considered already used and are 298 * skipped. 299 * 300 * You can use this by calling fdtdec_find_aliases_for_id() with an 301 * uninitialised array, then setting the elements that are returned to -1, 302 * say, then calling this function, perhaps with a different compat id. 303 * Any elements you get back that are >0 are new nodes added by the call 304 * to this function. 305 * 306 * Note that if you have some nodes with aliases and some without, you are 307 * sailing close to the wind. The call to fdtdec_find_aliases_for_id() with 308 * one compat_id may fill in positions for which you have aliases defined 309 * for another compat_id. When you later call *this* function with the second 310 * compat_id, the alias positions may already be used. A debug warning may 311 * be generated in this case, but it is safest to define aliases for all 312 * nodes when you care about the ordering. 313 */ 314 int fdtdec_add_aliases_for_id(const void *blob, const char *name, 315 enum fdt_compat_id id, int *node_list, int maxcount); 316 317 /* 318 * Get the name for a compatible ID 319 * 320 * @param id Compatible ID to look for 321 * @return compatible string for that id 322 */ 323 const char *fdtdec_get_compatible(enum fdt_compat_id id); 324 325 /* Look up a phandle and follow it to its node. Then return the offset 326 * of that node. 327 * 328 * @param blob FDT blob 329 * @param node node to examine 330 * @param prop_name name of property to find 331 * @return node offset if found, -ve error code on error 332 */ 333 int fdtdec_lookup_phandle(const void *blob, int node, const char *prop_name); 334 335 /** 336 * Look up a property in a node and return its contents in an integer 337 * array of given length. The property must have at least enough data for 338 * the array (4*count bytes). It may have more, but this will be ignored. 339 * 340 * @param blob FDT blob 341 * @param node node to examine 342 * @param prop_name name of property to find 343 * @param array array to fill with data 344 * @param count number of array elements 345 * @return 0 if ok, or -FDT_ERR_NOTFOUND if the property is not found, 346 * or -FDT_ERR_BADLAYOUT if not enough data 347 */ 348 int fdtdec_get_int_array(const void *blob, int node, const char *prop_name, 349 u32 *array, int count); 350 351 /** 352 * Look up a property in a node and return a pointer to its contents as a 353 * unsigned int array of given length. The property must have at least enough 354 * data for the array ('count' cells). It may have more, but this will be 355 * ignored. The data is not copied. 356 * 357 * Note that you must access elements of the array with fdt32_to_cpu(), 358 * since the elements will be big endian even on a little endian machine. 359 * 360 * @param blob FDT blob 361 * @param node node to examine 362 * @param prop_name name of property to find 363 * @param count number of array elements 364 * @return pointer to array if found, or NULL if the property is not 365 * found or there is not enough data 366 */ 367 const u32 *fdtdec_locate_array(const void *blob, int node, 368 const char *prop_name, int count); 369 370 /** 371 * Look up a boolean property in a node and return it. 372 * 373 * A boolean properly is true if present in the device tree and false if not 374 * present, regardless of its value. 375 * 376 * @param blob FDT blob 377 * @param node node to examine 378 * @param prop_name name of property to find 379 * @return 1 if the properly is present; 0 if it isn't present 380 */ 381 int fdtdec_get_bool(const void *blob, int node, const char *prop_name); 382 383 /** 384 * Decode a single GPIOs from an FDT. 385 * 386 * If the property is not found, then the GPIO structure will still be 387 * initialised, with gpio set to FDT_GPIO_NONE. This makes it easy to 388 * provide optional GPIOs. 389 * 390 * @param blob FDT blob to use 391 * @param node Node to look at 392 * @param prop_name Node property name 393 * @param gpio gpio elements to fill from FDT 394 * @return 0 if ok, -FDT_ERR_NOTFOUND if the property is missing. 395 */ 396 int fdtdec_decode_gpio(const void *blob, int node, const char *prop_name, 397 struct fdt_gpio_state *gpio); 398 399 /** 400 * Decode a list of GPIOs from an FDT. This creates a list of GPIOs with no 401 * terminating item. 402 * 403 * @param blob FDT blob to use 404 * @param node Node to look at 405 * @param prop_name Node property name 406 * @param gpio Array of gpio elements to fill from FDT. This will be 407 * untouched if either 0 or an error is returned 408 * @param max_count Maximum number of elements allowed 409 * @return number of GPIOs read if ok, -FDT_ERR_BADLAYOUT if max_count would 410 * be exceeded, or -FDT_ERR_NOTFOUND if the property is missing. 411 */ 412 int fdtdec_decode_gpios(const void *blob, int node, const char *prop_name, 413 struct fdt_gpio_state *gpio, int max_count); 414 415 /** 416 * Set up a GPIO pin according to the provided gpio information. At present this 417 * just requests the GPIO. 418 * 419 * If the gpio is FDT_GPIO_NONE, no action is taken. This makes it easy to 420 * deal with optional GPIOs. 421 * 422 * @param gpio GPIO info to use for set up 423 * @return 0 if all ok or gpio was FDT_GPIO_NONE; -1 on error 424 */ 425 int fdtdec_setup_gpio(struct fdt_gpio_state *gpio); 426 427 /** 428 * Look in the FDT for a config item with the given name and return its value 429 * as a 32-bit integer. The property must have at least 4 bytes of data. The 430 * value of the first cell is returned. 431 * 432 * @param blob FDT blob to use 433 * @param prop_name Node property name 434 * @param default_val default value to return if the property is not found 435 * @return integer value, if found, or default_val if not 436 */ 437 int fdtdec_get_config_int(const void *blob, const char *prop_name, 438 int default_val); 439 440 /** 441 * Look in the FDT for a config item with the given name 442 * and return whether it exists. 443 * 444 * @param blob FDT blob 445 * @param prop_name property name to look up 446 * @return 1, if it exists, or 0 if not 447 */ 448 int fdtdec_get_config_bool(const void *blob, const char *prop_name); 449 450 /** 451 * Look in the FDT for a config item with the given name and return its value 452 * as a string. 453 * 454 * @param blob FDT blob 455 * @param prop_name property name to look up 456 * @returns property string, NULL on error. 457 */ 458 char *fdtdec_get_config_string(const void *blob, const char *prop_name); 459 460 /* 461 * Look up a property in a node and return its contents in a byte 462 * array of given length. The property must have at least enough data for 463 * the array (count bytes). It may have more, but this will be ignored. 464 * 465 * @param blob FDT blob 466 * @param node node to examine 467 * @param prop_name name of property to find 468 * @param array array to fill with data 469 * @param count number of array elements 470 * @return 0 if ok, or -FDT_ERR_MISSING if the property is not found, 471 * or -FDT_ERR_BADLAYOUT if not enough data 472 */ 473 int fdtdec_get_byte_array(const void *blob, int node, const char *prop_name, 474 u8 *array, int count); 475 476 /** 477 * Look up a property in a node and return a pointer to its contents as a 478 * byte array of given length. The property must have at least enough data 479 * for the array (count bytes). It may have more, but this will be ignored. 480 * The data is not copied. 481 * 482 * @param blob FDT blob 483 * @param node node to examine 484 * @param prop_name name of property to find 485 * @param count number of array elements 486 * @return pointer to byte array if found, or NULL if the property is not 487 * found or there is not enough data 488 */ 489 const u8 *fdtdec_locate_byte_array(const void *blob, int node, 490 const char *prop_name, int count); 491 492 /** 493 * Look up a property in a node which contains a memory region address and 494 * size. Then return a pointer to this address. 495 * 496 * The property must hold one address with a length. This is only tested on 497 * 32-bit machines. 498 * 499 * @param blob FDT blob 500 * @param node node to examine 501 * @param prop_name name of property to find 502 * @param ptrp returns pointer to region, or NULL if no address 503 * @param size returns size of region 504 * @return 0 if ok, -1 on error (propery not found) 505 */ 506 int fdtdec_decode_region(const void *blob, int node, 507 const char *prop_name, void **ptrp, size_t *size); 508 #endif 509