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