Stephen Rothwell | 97e873e | 2007-05-01 16:26:07 +1000 | [diff] [blame] | 1 | /* |
| 2 | * Procedures for creating, accessing and interpreting the device tree. |
| 3 | * |
| 4 | * Paul Mackerras August 1996. |
| 5 | * Copyright (C) 1996-2005 Paul Mackerras. |
| 6 | * |
| 7 | * Adapted for 64bit PowerPC by Dave Engebretsen and Peter Bergner. |
| 8 | * {engebret|bergner}@us.ibm.com |
| 9 | * |
| 10 | * Adapted for sparc and sparc64 by David S. Miller davem@davemloft.net |
| 11 | * |
| 12 | * Reconsolidated from arch/x/kernel/prom.c by Stephen Rothwell. |
| 13 | * |
| 14 | * This program is free software; you can redistribute it and/or |
| 15 | * modify it under the terms of the GNU General Public License |
| 16 | * as published by the Free Software Foundation; either version |
| 17 | * 2 of the License, or (at your option) any later version. |
| 18 | */ |
| 19 | #include <linux/module.h> |
| 20 | #include <linux/of.h> |
Stephen Rothwell | 581b605 | 2007-04-24 16:46:53 +1000 | [diff] [blame] | 21 | #include <linux/spinlock.h> |
| 22 | |
Stephen Rothwell | 1ef4d42 | 2007-04-24 17:57:33 +1000 | [diff] [blame] | 23 | struct device_node *allnodes; |
| 24 | |
Stephen Rothwell | 581b605 | 2007-04-24 16:46:53 +1000 | [diff] [blame] | 25 | /* use when traversing tree through the allnext, child, sibling, |
| 26 | * or parent members of struct device_node. |
| 27 | */ |
| 28 | DEFINE_RWLOCK(devtree_lock); |
Stephen Rothwell | 97e873e | 2007-05-01 16:26:07 +1000 | [diff] [blame] | 29 | |
| 30 | int of_n_addr_cells(struct device_node *np) |
| 31 | { |
| 32 | const int *ip; |
| 33 | |
| 34 | do { |
| 35 | if (np->parent) |
| 36 | np = np->parent; |
| 37 | ip = of_get_property(np, "#address-cells", NULL); |
| 38 | if (ip) |
| 39 | return *ip; |
| 40 | } while (np->parent); |
| 41 | /* No #address-cells property for the root node */ |
| 42 | return OF_ROOT_NODE_ADDR_CELLS_DEFAULT; |
| 43 | } |
| 44 | EXPORT_SYMBOL(of_n_addr_cells); |
| 45 | |
| 46 | int of_n_size_cells(struct device_node *np) |
| 47 | { |
| 48 | const int *ip; |
| 49 | |
| 50 | do { |
| 51 | if (np->parent) |
| 52 | np = np->parent; |
| 53 | ip = of_get_property(np, "#size-cells", NULL); |
| 54 | if (ip) |
| 55 | return *ip; |
| 56 | } while (np->parent); |
| 57 | /* No #size-cells property for the root node */ |
| 58 | return OF_ROOT_NODE_SIZE_CELLS_DEFAULT; |
| 59 | } |
| 60 | EXPORT_SYMBOL(of_n_size_cells); |
| 61 | |
Stephen Rothwell | 581b605 | 2007-04-24 16:46:53 +1000 | [diff] [blame] | 62 | struct property *of_find_property(const struct device_node *np, |
| 63 | const char *name, |
| 64 | int *lenp) |
| 65 | { |
| 66 | struct property *pp; |
| 67 | |
Timur Tabi | 64e4566 | 2008-05-08 05:19:59 +1000 | [diff] [blame] | 68 | if (!np) |
| 69 | return NULL; |
| 70 | |
Stephen Rothwell | 581b605 | 2007-04-24 16:46:53 +1000 | [diff] [blame] | 71 | read_lock(&devtree_lock); |
| 72 | for (pp = np->properties; pp != 0; pp = pp->next) { |
| 73 | if (of_prop_cmp(pp->name, name) == 0) { |
| 74 | if (lenp != 0) |
| 75 | *lenp = pp->length; |
| 76 | break; |
| 77 | } |
| 78 | } |
| 79 | read_unlock(&devtree_lock); |
| 80 | |
| 81 | return pp; |
| 82 | } |
| 83 | EXPORT_SYMBOL(of_find_property); |
| 84 | |
Stephen Rothwell | 97e873e | 2007-05-01 16:26:07 +1000 | [diff] [blame] | 85 | /* |
| 86 | * Find a property with a given name for a given node |
| 87 | * and return the value. |
| 88 | */ |
| 89 | const void *of_get_property(const struct device_node *np, const char *name, |
| 90 | int *lenp) |
| 91 | { |
| 92 | struct property *pp = of_find_property(np, name, lenp); |
| 93 | |
| 94 | return pp ? pp->value : NULL; |
| 95 | } |
| 96 | EXPORT_SYMBOL(of_get_property); |
Stephen Rothwell | 0081cbc | 2007-05-01 16:29:19 +1000 | [diff] [blame] | 97 | |
| 98 | /** Checks if the given "compat" string matches one of the strings in |
| 99 | * the device's "compatible" property |
| 100 | */ |
| 101 | int of_device_is_compatible(const struct device_node *device, |
| 102 | const char *compat) |
| 103 | { |
| 104 | const char* cp; |
| 105 | int cplen, l; |
| 106 | |
| 107 | cp = of_get_property(device, "compatible", &cplen); |
| 108 | if (cp == NULL) |
| 109 | return 0; |
| 110 | while (cplen > 0) { |
| 111 | if (of_compat_cmp(cp, compat, strlen(compat)) == 0) |
| 112 | return 1; |
| 113 | l = strlen(cp) + 1; |
| 114 | cp += l; |
| 115 | cplen -= l; |
| 116 | } |
| 117 | |
| 118 | return 0; |
| 119 | } |
| 120 | EXPORT_SYMBOL(of_device_is_compatible); |
Stephen Rothwell | e679c5f | 2007-04-24 17:16:16 +1000 | [diff] [blame] | 121 | |
| 122 | /** |
Josh Boyer | 834d97d | 2008-03-27 00:33:14 +1100 | [diff] [blame] | 123 | * of_device_is_available - check if a device is available for use |
| 124 | * |
| 125 | * @device: Node to check for availability |
| 126 | * |
| 127 | * Returns 1 if the status property is absent or set to "okay" or "ok", |
| 128 | * 0 otherwise |
| 129 | */ |
| 130 | int of_device_is_available(const struct device_node *device) |
| 131 | { |
| 132 | const char *status; |
| 133 | int statlen; |
| 134 | |
| 135 | status = of_get_property(device, "status", &statlen); |
| 136 | if (status == NULL) |
| 137 | return 1; |
| 138 | |
| 139 | if (statlen > 0) { |
| 140 | if (!strcmp(status, "okay") || !strcmp(status, "ok")) |
| 141 | return 1; |
| 142 | } |
| 143 | |
| 144 | return 0; |
| 145 | } |
| 146 | EXPORT_SYMBOL(of_device_is_available); |
| 147 | |
| 148 | /** |
Stephen Rothwell | e679c5f | 2007-04-24 17:16:16 +1000 | [diff] [blame] | 149 | * of_get_parent - Get a node's parent if any |
| 150 | * @node: Node to get parent |
| 151 | * |
| 152 | * Returns a node pointer with refcount incremented, use |
| 153 | * of_node_put() on it when done. |
| 154 | */ |
| 155 | struct device_node *of_get_parent(const struct device_node *node) |
| 156 | { |
| 157 | struct device_node *np; |
| 158 | |
| 159 | if (!node) |
| 160 | return NULL; |
| 161 | |
| 162 | read_lock(&devtree_lock); |
| 163 | np = of_node_get(node->parent); |
| 164 | read_unlock(&devtree_lock); |
| 165 | return np; |
| 166 | } |
| 167 | EXPORT_SYMBOL(of_get_parent); |
Stephen Rothwell | d1cd355 | 2007-04-24 17:21:29 +1000 | [diff] [blame] | 168 | |
| 169 | /** |
Michael Ellerman | f4eb010 | 2007-10-26 16:54:31 +1000 | [diff] [blame] | 170 | * of_get_next_parent - Iterate to a node's parent |
| 171 | * @node: Node to get parent of |
| 172 | * |
| 173 | * This is like of_get_parent() except that it drops the |
| 174 | * refcount on the passed node, making it suitable for iterating |
| 175 | * through a node's parents. |
| 176 | * |
| 177 | * Returns a node pointer with refcount incremented, use |
| 178 | * of_node_put() on it when done. |
| 179 | */ |
| 180 | struct device_node *of_get_next_parent(struct device_node *node) |
| 181 | { |
| 182 | struct device_node *parent; |
| 183 | |
| 184 | if (!node) |
| 185 | return NULL; |
| 186 | |
| 187 | read_lock(&devtree_lock); |
| 188 | parent = of_node_get(node->parent); |
| 189 | of_node_put(node); |
| 190 | read_unlock(&devtree_lock); |
| 191 | return parent; |
| 192 | } |
| 193 | |
| 194 | /** |
Stephen Rothwell | d1cd355 | 2007-04-24 17:21:29 +1000 | [diff] [blame] | 195 | * of_get_next_child - Iterate a node childs |
| 196 | * @node: parent node |
| 197 | * @prev: previous child of the parent node, or NULL to get first |
| 198 | * |
| 199 | * Returns a node pointer with refcount incremented, use |
| 200 | * of_node_put() on it when done. |
| 201 | */ |
| 202 | struct device_node *of_get_next_child(const struct device_node *node, |
| 203 | struct device_node *prev) |
| 204 | { |
| 205 | struct device_node *next; |
| 206 | |
| 207 | read_lock(&devtree_lock); |
| 208 | next = prev ? prev->sibling : node->child; |
| 209 | for (; next; next = next->sibling) |
| 210 | if (of_node_get(next)) |
| 211 | break; |
| 212 | of_node_put(prev); |
| 213 | read_unlock(&devtree_lock); |
| 214 | return next; |
| 215 | } |
| 216 | EXPORT_SYMBOL(of_get_next_child); |
Stephen Rothwell | 1ef4d42 | 2007-04-24 17:57:33 +1000 | [diff] [blame] | 217 | |
| 218 | /** |
| 219 | * of_find_node_by_path - Find a node matching a full OF path |
| 220 | * @path: The full path to match |
| 221 | * |
| 222 | * Returns a node pointer with refcount incremented, use |
| 223 | * of_node_put() on it when done. |
| 224 | */ |
| 225 | struct device_node *of_find_node_by_path(const char *path) |
| 226 | { |
| 227 | struct device_node *np = allnodes; |
| 228 | |
| 229 | read_lock(&devtree_lock); |
| 230 | for (; np; np = np->allnext) { |
| 231 | if (np->full_name && (of_node_cmp(np->full_name, path) == 0) |
| 232 | && of_node_get(np)) |
| 233 | break; |
| 234 | } |
| 235 | read_unlock(&devtree_lock); |
| 236 | return np; |
| 237 | } |
| 238 | EXPORT_SYMBOL(of_find_node_by_path); |
| 239 | |
| 240 | /** |
| 241 | * of_find_node_by_name - Find a node by its "name" property |
| 242 | * @from: The node to start searching from or NULL, the node |
| 243 | * you pass will not be searched, only the next one |
| 244 | * will; typically, you pass what the previous call |
| 245 | * returned. of_node_put() will be called on it |
| 246 | * @name: The name string to match against |
| 247 | * |
| 248 | * Returns a node pointer with refcount incremented, use |
| 249 | * of_node_put() on it when done. |
| 250 | */ |
| 251 | struct device_node *of_find_node_by_name(struct device_node *from, |
| 252 | const char *name) |
| 253 | { |
| 254 | struct device_node *np; |
| 255 | |
| 256 | read_lock(&devtree_lock); |
| 257 | np = from ? from->allnext : allnodes; |
| 258 | for (; np; np = np->allnext) |
| 259 | if (np->name && (of_node_cmp(np->name, name) == 0) |
| 260 | && of_node_get(np)) |
| 261 | break; |
| 262 | of_node_put(from); |
| 263 | read_unlock(&devtree_lock); |
| 264 | return np; |
| 265 | } |
| 266 | EXPORT_SYMBOL(of_find_node_by_name); |
| 267 | |
| 268 | /** |
| 269 | * of_find_node_by_type - Find a node by its "device_type" property |
| 270 | * @from: The node to start searching from, or NULL to start searching |
| 271 | * the entire device tree. The node you pass will not be |
| 272 | * searched, only the next one will; typically, you pass |
| 273 | * what the previous call returned. of_node_put() will be |
| 274 | * called on from for you. |
| 275 | * @type: The type string to match against |
| 276 | * |
| 277 | * Returns a node pointer with refcount incremented, use |
| 278 | * of_node_put() on it when done. |
| 279 | */ |
| 280 | struct device_node *of_find_node_by_type(struct device_node *from, |
| 281 | const char *type) |
| 282 | { |
| 283 | struct device_node *np; |
| 284 | |
| 285 | read_lock(&devtree_lock); |
| 286 | np = from ? from->allnext : allnodes; |
| 287 | for (; np; np = np->allnext) |
| 288 | if (np->type && (of_node_cmp(np->type, type) == 0) |
| 289 | && of_node_get(np)) |
| 290 | break; |
| 291 | of_node_put(from); |
| 292 | read_unlock(&devtree_lock); |
| 293 | return np; |
| 294 | } |
| 295 | EXPORT_SYMBOL(of_find_node_by_type); |
| 296 | |
| 297 | /** |
| 298 | * of_find_compatible_node - Find a node based on type and one of the |
| 299 | * tokens in its "compatible" property |
| 300 | * @from: The node to start searching from or NULL, the node |
| 301 | * you pass will not be searched, only the next one |
| 302 | * will; typically, you pass what the previous call |
| 303 | * returned. of_node_put() will be called on it |
| 304 | * @type: The type string to match "device_type" or NULL to ignore |
| 305 | * @compatible: The string to match to one of the tokens in the device |
| 306 | * "compatible" list. |
| 307 | * |
| 308 | * Returns a node pointer with refcount incremented, use |
| 309 | * of_node_put() on it when done. |
| 310 | */ |
| 311 | struct device_node *of_find_compatible_node(struct device_node *from, |
| 312 | const char *type, const char *compatible) |
| 313 | { |
| 314 | struct device_node *np; |
| 315 | |
| 316 | read_lock(&devtree_lock); |
| 317 | np = from ? from->allnext : allnodes; |
| 318 | for (; np; np = np->allnext) { |
| 319 | if (type |
| 320 | && !(np->type && (of_node_cmp(np->type, type) == 0))) |
| 321 | continue; |
| 322 | if (of_device_is_compatible(np, compatible) && of_node_get(np)) |
| 323 | break; |
| 324 | } |
| 325 | of_node_put(from); |
| 326 | read_unlock(&devtree_lock); |
| 327 | return np; |
| 328 | } |
| 329 | EXPORT_SYMBOL(of_find_compatible_node); |
Grant Likely | 283029d | 2008-01-09 06:20:40 +1100 | [diff] [blame] | 330 | |
| 331 | /** |
| 332 | * of_match_node - Tell if an device_node has a matching of_match structure |
| 333 | * @matches: array of of device match structures to search in |
| 334 | * @node: the of device structure to match against |
| 335 | * |
| 336 | * Low level utility function used by device matching. |
| 337 | */ |
| 338 | const struct of_device_id *of_match_node(const struct of_device_id *matches, |
| 339 | const struct device_node *node) |
| 340 | { |
| 341 | while (matches->name[0] || matches->type[0] || matches->compatible[0]) { |
| 342 | int match = 1; |
| 343 | if (matches->name[0]) |
| 344 | match &= node->name |
| 345 | && !strcmp(matches->name, node->name); |
| 346 | if (matches->type[0]) |
| 347 | match &= node->type |
| 348 | && !strcmp(matches->type, node->type); |
| 349 | if (matches->compatible[0]) |
| 350 | match &= of_device_is_compatible(node, |
| 351 | matches->compatible); |
| 352 | if (match) |
| 353 | return matches; |
| 354 | matches++; |
| 355 | } |
| 356 | return NULL; |
| 357 | } |
| 358 | EXPORT_SYMBOL(of_match_node); |
| 359 | |
| 360 | /** |
| 361 | * of_find_matching_node - Find a node based on an of_device_id match |
| 362 | * table. |
| 363 | * @from: The node to start searching from or NULL, the node |
| 364 | * you pass will not be searched, only the next one |
| 365 | * will; typically, you pass what the previous call |
| 366 | * returned. of_node_put() will be called on it |
| 367 | * @matches: array of of device match structures to search in |
| 368 | * |
| 369 | * Returns a node pointer with refcount incremented, use |
| 370 | * of_node_put() on it when done. |
| 371 | */ |
| 372 | struct device_node *of_find_matching_node(struct device_node *from, |
| 373 | const struct of_device_id *matches) |
| 374 | { |
| 375 | struct device_node *np; |
| 376 | |
| 377 | read_lock(&devtree_lock); |
| 378 | np = from ? from->allnext : allnodes; |
| 379 | for (; np; np = np->allnext) { |
| 380 | if (of_match_node(matches, np) && of_node_get(np)) |
| 381 | break; |
| 382 | } |
| 383 | of_node_put(from); |
| 384 | read_unlock(&devtree_lock); |
| 385 | return np; |
| 386 | } |
| 387 | EXPORT_SYMBOL(of_find_matching_node); |
Grant Likely | 3f07af4 | 2008-07-25 22:25:13 -0400 | [diff] [blame] | 388 | |
| 389 | /** |
| 390 | * of_modalias_table: Table of explicit compatible ==> modalias mappings |
| 391 | * |
| 392 | * This table allows particulare compatible property values to be mapped |
| 393 | * to modalias strings. This is useful for busses which do not directly |
| 394 | * understand the OF device tree but are populated based on data contained |
| 395 | * within the device tree. SPI and I2C are the two current users of this |
| 396 | * table. |
| 397 | * |
| 398 | * In most cases, devices do not need to be listed in this table because |
| 399 | * the modalias value can be derived directly from the compatible table. |
| 400 | * However, if for any reason a value cannot be derived, then this table |
| 401 | * provides a method to override the implicit derivation. |
| 402 | * |
| 403 | * At the moment, a single table is used for all bus types because it is |
| 404 | * assumed that the data size is small and that the compatible values |
| 405 | * should already be distinct enough to differentiate between SPI, I2C |
| 406 | * and other devices. |
| 407 | */ |
| 408 | struct of_modalias_table { |
| 409 | char *of_device; |
| 410 | char *modalias; |
| 411 | }; |
| 412 | static struct of_modalias_table of_modalias_table[] = { |
| 413 | /* Empty for now; add entries as needed */ |
| 414 | }; |
| 415 | |
| 416 | /** |
| 417 | * of_modalias_node - Lookup appropriate modalias for a device node |
| 418 | * @node: pointer to a device tree node |
| 419 | * @modalias: Pointer to buffer that modalias value will be copied into |
| 420 | * @len: Length of modalias value |
| 421 | * |
| 422 | * Based on the value of the compatible property, this routine will determine |
Grant Likely | 58f467c | 2008-10-08 05:05:29 +0000 | [diff] [blame^] | 423 | * an appropriate modalias value for a particular device tree node. Two |
| 424 | * separate methods are attempted to derive a modalias value. |
Grant Likely | 3f07af4 | 2008-07-25 22:25:13 -0400 | [diff] [blame] | 425 | * |
| 426 | * First method is to lookup the compatible value in of_modalias_table. |
Grant Likely | 58f467c | 2008-10-08 05:05:29 +0000 | [diff] [blame^] | 427 | * Second is to strip off the manufacturer prefix from the first |
| 428 | * compatible entry and use the remainder as modalias |
Grant Likely | 3f07af4 | 2008-07-25 22:25:13 -0400 | [diff] [blame] | 429 | * |
| 430 | * This routine returns 0 on success |
| 431 | */ |
| 432 | int of_modalias_node(struct device_node *node, char *modalias, int len) |
| 433 | { |
| 434 | int i, cplen; |
| 435 | const char *compatible; |
| 436 | const char *p; |
| 437 | |
| 438 | /* 1. search for exception list entry */ |
| 439 | for (i = 0; i < ARRAY_SIZE(of_modalias_table); i++) { |
| 440 | compatible = of_modalias_table[i].of_device; |
| 441 | if (!of_device_is_compatible(node, compatible)) |
| 442 | continue; |
| 443 | strlcpy(modalias, of_modalias_table[i].modalias, len); |
| 444 | return 0; |
| 445 | } |
| 446 | |
| 447 | compatible = of_get_property(node, "compatible", &cplen); |
| 448 | if (!compatible) |
| 449 | return -ENODEV; |
| 450 | |
Grant Likely | 58f467c | 2008-10-08 05:05:29 +0000 | [diff] [blame^] | 451 | /* 2. take first compatible entry and strip manufacturer */ |
Grant Likely | 3f07af4 | 2008-07-25 22:25:13 -0400 | [diff] [blame] | 452 | p = strchr(compatible, ','); |
| 453 | if (!p) |
| 454 | return -ENODEV; |
| 455 | p++; |
| 456 | strlcpy(modalias, p, len); |
| 457 | return 0; |
| 458 | } |
| 459 | EXPORT_SYMBOL_GPL(of_modalias_node); |
| 460 | |