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