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