drivers/base/devres.c

   1 /*
   2  * drivers/base/devres.c - device resource management
   3  *
   4  * Copyright (c) 2006  SUSE Linux Products GmbH
   5  * Copyright (c) 2006  Tejun Heo <teheo@suse.de>
   6  *
   7  * This file is released under the GPLv2.
   8  */
   9
  10 #include <linux/device.h>
  11 #include <linux/module.h>
  12
  13 struct devres_node {
  14         struct list_head                entry;
  15         dr_release_t                    release;
  16 #ifdef CONFIG_DEBUG_DEVRES
  17         const char                      *name;
  18         size_t                          size;
  19 #endif
  20 };
  21
  22 struct devres {
  23         struct devres_node              node;
  24         /* -- 3 pointers */
  25         unsigned long long              data[]; /* guarantee ull alignment */
  26 };
  27
  28 struct devres_group {
  29         struct devres_node              node[2];
  30         void                            *id;
  31         int                             color;
  32         /* -- 8 pointers */
  33 };
  34
  35 #ifdef CONFIG_DEBUG_DEVRES
  36 static int log_devres = 0;
  37 module_param_named(log, log_devres, int, S_IRUGO | S_IWUSR);
  38
  39 static void set_node_dbginfo(struct devres_node *node, const char *name,
  40                              size_t size)
  41 {
  42         node->name = name;
  43         node->size = size;
  44 }
  45
  46 static void devres_log(struct device *dev, struct devres_node *node,
  47                        const char *op)
  48 {
  49         if (unlikely(log_devres))
  50                 dev_printk(KERN_ERR, dev, "DEVRES %3s %p %s (%lu bytes)\n",
  51                            op, node, node->name, (unsigned long)node->size);
  52 }
  53 #else /* CONFIG_DEBUG_DEVRES */
  54 #define set_node_dbginfo(node, n, s)    do {} while (0)
  55 #define devres_log(dev, node, op)       do {} while (0)
  56 #endif /* CONFIG_DEBUG_DEVRES */
  57
  58 /*
  59  * Release functions for devres group.  These callbacks are used only
  60  * for identification.
  61  */
  62 static void group_open_release(struct device *dev, void *res)
  63 {
  64         /* noop */
  65 }
  66
  67 static void group_close_release(struct device *dev, void *res)
  68 {
  69         /* noop */
  70 }
  71
  72 static struct devres_group * node_to_group(struct devres_node *node)
  73 {
  74         if (node->release == &group_open_release)
  75                 return container_of(node, struct devres_group, node[0]);
  76         if (node->release == &group_close_release)
  77                 return container_of(node, struct devres_group, node[1]);
  78         return NULL;
  79 }
  80
  81 static __always_inline struct devres * alloc_dr(dr_release_t release,
  82                                                 size_t size, gfp_t gfp)
  83 {
  84         size_t tot_size = sizeof(struct devres) + size;
  85         struct devres *dr;
  86
  87         dr = kmalloc_track_caller(tot_size, gfp);
  88         if (unlikely(!dr))
  89                 return NULL;
  90
  91         memset(dr, 0, tot_size);
  92         INIT_LIST_HEAD(&dr->node.entry);
  93         dr->node.release = release;
  94         return dr;
  95 }
  96
  97 static void add_dr(struct device *dev, struct devres_node *node)
  98 {
  99         devres_log(dev, node, "ADD");
 100         BUG_ON(!list_empty(&node->entry));
 101         list_add_tail(&node->entry, &dev->devres_head);
 102 }
 103
 104 /**
 105  * devres_alloc - Allocate device resource data
 106  * @release: Release function devres will be associated with
 107  * @size: Allocation size
 108  * @gfp: Allocation flags
 109  *
 110  * allocate devres of @size bytes.  The allocated area is zeroed, then
 111  * associated with @release.  The returned pointer can be passed to
 112  * other devres_*() functions.
 113  *
 114  * RETURNS:
 115  * Pointer to allocated devres on success, NULL on failure.
 116  */
 117 #ifdef CONFIG_DEBUG_DEVRES
 118 void * __devres_alloc(dr_release_t release, size_t size, gfp_t gfp,
 119                       const char *name)
 120 {
 121         struct devres *dr;
 122
 123         dr = alloc_dr(release, size, gfp);
 124         if (unlikely(!dr))
 125                 return NULL;
 126         set_node_dbginfo(&dr->node, name, size);
 127         return dr->data;
 128 }
 129 EXPORT_SYMBOL_GPL(__devres_alloc);
 130 #else
 131 void * devres_alloc(dr_release_t release, size_t size, gfp_t gfp)
 132 {
 133         struct devres *dr;
 134
 135         dr = alloc_dr(release, size, gfp);
 136         if (unlikely(!dr))
 137                 return NULL;
 138         return dr->data;
 139 }
 140 EXPORT_SYMBOL_GPL(devres_alloc);
 141 #endif
 142
 143 /**
 144  * devres_free - Free device resource data
 145  * @res: Pointer to devres data to free
 146  *
 147  * Free devres created with devres_alloc().
 148  */
 149 void devres_free(void *res)
 150 {
 151         if (res) {
 152                 struct devres *dr = container_of(res, struct devres, data);
 153
 154                 BUG_ON(!list_empty(&dr->node.entry));
 155                 kfree(dr);
 156         }
 157 }
 158 EXPORT_SYMBOL_GPL(devres_free);
 159
 160 /**
 161  * devres_add - Register device resource
 162  * @dev: Device to add resource to
 163  * @res: Resource to register
 164  *
 165  * Register devres @res to @dev.  @res should have been allocated
 166  * using devres_alloc().  On driver detach, the associated release
 167  * function will be invoked and devres will be freed automatically.
 168  */
 169 void devres_add(struct device *dev, void *res)
 170 {
 171         struct devres *dr = container_of(res, struct devres, data);
 172         unsigned long flags;
 173
 174         spin_lock_irqsave(&dev->devres_lock, flags);
 175         add_dr(dev, &dr->node);
 176         spin_unlock_irqrestore(&dev->devres_lock, flags);
 177 }
 178 EXPORT_SYMBOL_GPL(devres_add);
 179
 180 static struct devres *find_dr(struct device *dev, dr_release_t release,
 181                               dr_match_t match, void *match_data)
 182 {
 183         struct devres_node *node;
 184
 185         list_for_each_entry_reverse(node, &dev->devres_head, entry) {
 186                 struct devres *dr = container_of(node, struct devres, node);
 187
 188                 if (node->release != release)
 189                         continue;
 190                 if (match && !match(dev, dr->data, match_data))
 191                         continue;
 192                 return dr;
 193         }
 194
 195         return NULL;
 196 }
 197
 198 /**
 199  * devres_find - Find device resource
 200  * @dev: Device to lookup resource from
 201  * @release: Look for resources associated with this release function
 202  * @match: Match function (optional)
 203  * @match_data: Data for the match function
 204  *
 205  * Find the latest devres of @dev which is associated with @release
 206  * and for which @match returns 1.  If @match is NULL, it's considered
 207  * to match all.
 208  *
 209  * RETURNS:
 210  * Pointer to found devres, NULL if not found.
 211  */
 212 void * devres_find(struct device *dev, dr_release_t release,
 213                    dr_match_t match, void *match_data)
 214 {
 215         struct devres *dr;
 216         unsigned long flags;
 217
 218         spin_lock_irqsave(&dev->devres_lock, flags);
 219         dr = find_dr(dev, release, match, match_data);
 220         spin_unlock_irqrestore(&dev->devres_lock, flags);
 221
 222         if (dr)
 223                 return dr->data;
 224         return NULL;
 225 }
 226 EXPORT_SYMBOL_GPL(devres_find);
 227
 228 /**
 229  * devres_get - Find devres, if non-existent, add one atomically
 230  * @dev: Device to lookup or add devres for
 231  * @new_res: Pointer to new initialized devres to add if not found
 232  * @match: Match function (optional)
 233  * @match_data: Data for the match function
 234  *
 235  * Find the latest devres of @dev which has the same release function
 236  * as @new_res and for which @match return 1.  If found, @new_res is
 237  * freed; otherwise, @new_res is added atomically.
 238  *
 239  * RETURNS:
 240  * Pointer to found or added devres.
 241  */
 242 void * devres_get(struct device *dev, void *new_res,
 243                   dr_match_t match, void *match_data)
 244 {
 245         struct devres *new_dr = container_of(new_res, struct devres, data);
 246         struct devres *dr;
 247         unsigned long flags;
 248
 249         spin_lock_irqsave(&dev->devres_lock, flags);
 250         dr = find_dr(dev, new_dr->node.release, match, match_data);
 251         if (!dr) {
 252                 add_dr(dev, &new_dr->node);
 253                 dr = new_dr;
 254                 new_dr = NULL;
 255         }
 256         spin_unlock_irqrestore(&dev->devres_lock, flags);
 257         devres_free(new_dr);
 258
 259         return dr->data;
 260 }
 261 EXPORT_SYMBOL_GPL(devres_get);
 262
 263 /**
 264  * devres_remove - Find a device resource and remove it
 265  * @dev: Device to find resource from
 266  * @release: Look for resources associated with this release function
 267  * @match: Match function (optional)
 268  * @match_data: Data for the match function
 269  *
 270  * Find the latest devres of @dev associated with @release and for
 271  * which @match returns 1.  If @match is NULL, it's considered to
 272  * match all.  If found, the resource is removed atomically and
 273  * returned.
 274  *
 275  * RETURNS:
 276  * Pointer to removed devres on success, NULL if not found.
 277  */
 278 void * devres_remove(struct device *dev, dr_release_t release,
 279                      dr_match_t match, void *match_data)
 280 {
 281         struct devres *dr;
 282         unsigned long flags;
 283
 284         spin_lock_irqsave(&dev->devres_lock, flags);
 285         dr = find_dr(dev, release, match, match_data);
 286         if (dr) {
 287                 list_del_init(&dr->node.entry);
 288                 devres_log(dev, &dr->node, "REM");
 289         }
 290         spin_unlock_irqrestore(&dev->devres_lock, flags);
 291
 292         if (dr)
 293                 return dr->data;
 294         return NULL;
 295 }
 296 EXPORT_SYMBOL_GPL(devres_remove);
 297
 298 /**
 299  * devres_destroy - Find a device resource and destroy it
 300  * @dev: Device to find resource from
 301  * @release: Look for resources associated with this release function
 302  * @match: Match function (optional)
 303  * @match_data: Data for the match function
 304  *
 305  * Find the latest devres of @dev associated with @release and for
 306  * which @match returns 1.  If @match is NULL, it's considered to
 307  * match all.  If found, the resource is removed atomically and freed.
 308  *
 309  * RETURNS:
 310  * 0 if devres is found and freed, -ENOENT if not found.
 311  */
 312 int devres_destroy(struct device *dev, dr_release_t release,
 313                    dr_match_t match, void *match_data)
 314 {
 315         void *res;
 316
 317         res = devres_remove(dev, release, match, match_data);
 318         if (unlikely(!res))
 319                 return -ENOENT;
 320
 321         devres_free(res);
 322         return 0;
 323 }
 324 EXPORT_SYMBOL_GPL(devres_destroy);
 325
 326 static int remove_nodes(struct device *dev,
 327                         struct list_head *first, struct list_head *end,
 328                         struct list_head *todo)
 329 {
 330         int cnt = 0, nr_groups = 0;
 331         struct list_head *cur;
 332
 333         /* First pass - move normal devres entries to @todo and clear
 334          * devres_group colors.
 335          */
 336         cur = first;
 337         while (cur != end) {
 338                 struct devres_node *node;
 339                 struct devres_group *grp;
 340
 341                 node = list_entry(cur, struct devres_node, entry);
 342                 cur = cur->next;
 343
 344                 grp = node_to_group(node);
 345                 if (grp) {
 346                         /* clear color of group markers in the first pass */
 347                         grp->color = 0;
 348                         nr_groups++;
 349                 } else {
 350                         /* regular devres entry */
 351                         if (&node->entry == first)
 352                                 first = first->next;
 353                         list_move_tail(&node->entry, todo);
 354                         cnt++;
 355                 }
 356         }
 357
 358         if (!nr_groups)
 359                 return cnt;
 360
 361         /* Second pass - Scan groups and color them.  A group gets
 362          * color value of two iff the group is wholly contained in
 363          * [cur, end).  That is, for a closed group, both opening and
 364          * closing markers should be in the range, while just the
 365          * opening marker is enough for an open group.
 366          */
 367         cur = first;
 368         while (cur != end) {
 369                 struct devres_node *node;
 370                 struct devres_group *grp;
 371
 372                 node = list_entry(cur, struct devres_node, entry);
 373                 cur = cur->next;
 374
 375                 grp = node_to_group(node);
 376                 BUG_ON(!grp || list_empty(&grp->node[0].entry));
 377
 378                 grp->color++;
 379                 if (list_empty(&grp->node[1].entry))
 380                         grp->color++;
 381
 382                 BUG_ON(grp->color <= 0 || grp->color > 2);
 383                 if (grp->color == 2) {
 384                         /* No need to update cur or end.  The removed
 385                          * nodes are always before both.
 386                          */
 387                         list_move_tail(&grp->node[0].entry, todo);
 388                         list_del_init(&grp->node[1].entry);
 389                 }
 390         }
 391
 392         return cnt;
 393 }
 394
 395 static int release_nodes(struct device *dev, struct list_head *first,
 396                          struct list_head *end, unsigned long flags)
 397 {
 398         LIST_HEAD(todo);
 399         int cnt;
 400         struct devres *dr, *tmp;
 401
 402         cnt = remove_nodes(dev, first, end, &todo);
 403
 404         spin_unlock_irqrestore(&dev->devres_lock, flags);
 405
 406         /* Release.  Note that both devres and devres_group are
 407          * handled as devres in the following loop.  This is safe.
 408          */
 409         list_for_each_entry_safe_reverse(dr, tmp, &todo, node.entry) {
 410                 devres_log(dev, &dr->node, "REL");
 411                 dr->node.release(dev, dr->data);
 412                 kfree(dr);
 413         }
 414
 415         return cnt;
 416 }
 417
 418 /**
 419  * devres_release_all - Release all resources
 420  * @dev: Device to release resources for
 421  *
 422  * Release all resources associated with @dev.  This function is
 423  * called on driver detach.
 424  */
 425 int devres_release_all(struct device *dev)
 426 {
 427         unsigned long flags;
 428
 429         spin_lock_irqsave(&dev->devres_lock, flags);
 430         return release_nodes(dev, dev->devres_head.next, &dev->devres_head,
 431                              flags);
 432 }
 433
 434 /**
 435  * devres_open_group - Open a new devres group
 436  * @dev: Device to open devres group for
 437  * @id: Separator ID
 438  * @gfp: Allocation flags
 439  *
 440  * Open a new devres group for @dev with @id.  For @id, using a
 441  * pointer to an object which won't be used for another group is
 442  * recommended.  If @id is NULL, address-wise unique ID is created.
 443  *
 444  * RETURNS:
 445  * ID of the new group, NULL on failure.
 446  */
 447 void * devres_open_group(struct device *dev, void *id, gfp_t gfp)
 448 {
 449         struct devres_group *grp;
 450         unsigned long flags;
 451
 452         grp = kmalloc(sizeof(*grp), gfp);
 453         if (unlikely(!grp))
 454                 return NULL;
 455
 456         grp->node[0].release = &group_open_release;
 457         grp->node[1].release = &group_close_release;
 458         INIT_LIST_HEAD(&grp->node[0].entry);
 459         INIT_LIST_HEAD(&grp->node[1].entry);
 460         set_node_dbginfo(&grp->node[0], "grp<", 0);
 461         set_node_dbginfo(&grp->node[1], "grp>", 0);
 462         grp->id = grp;
 463         if (id)
 464                 grp->id = id;
 465
 466         spin_lock_irqsave(&dev->devres_lock, flags);
 467         add_dr(dev, &grp->node[0]);
 468         spin_unlock_irqrestore(&dev->devres_lock, flags);
 469         return grp->id;
 470 }
 471 EXPORT_SYMBOL_GPL(devres_open_group);
 472
 473 /* Find devres group with ID @id.  If @id is NULL, look for the latest. */
 474 static struct devres_group * find_group(struct device *dev, void *id)
 475 {
 476         struct devres_node *node;
 477
 478         list_for_each_entry_reverse(node, &dev->devres_head, entry) {
 479                 struct devres_group *grp;
 480
 481                 if (node->release != &group_open_release)
 482                         continue;
 483
 484                 grp = container_of(node, struct devres_group, node[0]);
 485
 486                 if (id) {
 487                         if (grp->id == id)
 488                                 return grp;
 489                 } else if (list_empty(&grp->node[1].entry))
 490                         return grp;
 491         }
 492
 493         return NULL;
 494 }
 495
 496 /**
 497  * devres_close_group - Close a devres group
 498  * @dev: Device to close devres group for
 499  * @id: ID of target group, can be NULL
 500  *
 501  * Close the group identified by @id.  If @id is NULL, the latest open
 502  * group is selected.
 503  */
 504 void devres_close_group(struct device *dev, void *id)
 505 {
 506         struct devres_group *grp;
 507         unsigned long flags;
 508
 509         spin_lock_irqsave(&dev->devres_lock, flags);
 510
 511         grp = find_group(dev, id);
 512         if (grp)
 513                 add_dr(dev, &grp->node[1]);
 514         else
 515                 WARN_ON(1);
 516
 517         spin_unlock_irqrestore(&dev->devres_lock, flags);
 518 }
 519 EXPORT_SYMBOL_GPL(devres_close_group);
 520
 521 /**
 522  * devres_remove_group - Remove a devres group
 523  * @dev: Device to remove group for
 524  * @id: ID of target group, can be NULL
 525  *
 526  * Remove the group identified by @id.  If @id is NULL, the latest
 527  * open group is selected.  Note that removing a group doesn't affect
 528  * any other resources.
 529  */
 530 void devres_remove_group(struct device *dev, void *id)
 531 {
 532         struct devres_group *grp;
 533         unsigned long flags;
 534
 535         spin_lock_irqsave(&dev->devres_lock, flags);
 536
 537         grp = find_group(dev, id);
 538         if (grp) {
 539                 list_del_init(&grp->node[0].entry);
 540                 list_del_init(&grp->node[1].entry);
 541                 devres_log(dev, &grp->node[0], "REM");
 542         } else
 543                 WARN_ON(1);
 544
 545         spin_unlock_irqrestore(&dev->devres_lock, flags);
 546
 547         kfree(grp);
 548 }
 549 EXPORT_SYMBOL_GPL(devres_remove_group);
 550
 551 /**
 552  * devres_release_group - Release resources in a devres group
 553  * @dev: Device to release group for
 554  * @id: ID of target group, can be NULL
 555  *
 556  * Release all resources in the group identified by @id.  If @id is
 557  * NULL, the latest open group is selected.  The selected group and
 558  * groups properly nested inside the selected group are removed.
 559  *
 560  * RETURNS:
 561  * The number of released non-group resources.
 562  */
 563 int devres_release_group(struct device *dev, void *id)
 564 {
 565         struct devres_group *grp;
 566         unsigned long flags;
 567         int cnt = 0;
 568
 569         spin_lock_irqsave(&dev->devres_lock, flags);
 570
 571         grp = find_group(dev, id);
 572         if (grp) {
 573                 struct list_head *first = &grp->node[0].entry;
 574                 struct list_head *end = &dev->devres_head;
 575
 576                 if (!list_empty(&grp->node[1].entry))
 577                         end = grp->node[1].entry.next;
 578
 579                 cnt = release_nodes(dev, first, end, flags);
 580         } else {
 581                 WARN_ON(1);
 582                 spin_unlock_irqrestore(&dev->devres_lock, flags);
 583         }
 584
 585         return cnt;
 586 }
 587 EXPORT_SYMBOL_GPL(devres_release_group);
 588
 589 /*
 590  * Managed kzalloc/kfree
 591  */
 592 static void devm_kzalloc_release(struct device *dev, void *res)
 593 {
 594         /* noop */
 595 }
 596
 597 static int devm_kzalloc_match(struct device *dev, void *res, void *data)
 598 {
 599         return res == data;
 600 }
 601
 602 /**
 603  * devm_kzalloc - Managed kzalloc
 604  * @dev: Device to allocate memory for
 605  * @size: Allocation size
 606  * @gfp: Allocation gfp flags
 607  *
 608  * Managed kzalloc.  Memory allocated with this function is
 609  * automatically freed on driver detach.  Like all other devres
 610  * resources, guaranteed alignment is unsigned long long.
 611  *
 612  * RETURNS:
 613  * Pointer to allocated memory on success, NULL on failure.
 614  */
 615 void * devm_kzalloc(struct device *dev, size_t size, gfp_t gfp)
 616 {
 617         struct devres *dr;
 618
 619         /* use raw alloc_dr for kmalloc caller tracing */
 620         dr = alloc_dr(devm_kzalloc_release, size, gfp);
 621         if (unlikely(!dr))
 622                 return NULL;
 623
 624         set_node_dbginfo(&dr->node, "devm_kzalloc_release", size);
 625         devres_add(dev, dr->data);
 626         return dr->data;
 627 }
 628 EXPORT_SYMBOL_GPL(devm_kzalloc);
 629
 630 /**
 631  * devm_kfree - Managed kfree
 632  * @dev: Device this memory belongs to
 633  * @p: Memory to free
 634  *
 635  * Free memory allocated with dev_kzalloc().
 636  */
 637 void devm_kfree(struct device *dev, void *p)
 638 {
 639         int rc;
 640
 641         rc = devres_destroy(dev, devm_kzalloc_release, devm_kzalloc_match, p);
 642         WARN_ON(rc);
 643 }
 644 EXPORT_SYMBOL_GPL(devm_kfree);