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 #include "base.h"
  14
  15 struct devres_node {
  16         struct list_head                entry;
  17         dr_release_t                    release;
  18 #ifdef CONFIG_DEBUG_DEVRES
  19         const char                      *name;
  20         size_t                          size;
  21 #endif
  22 };
  23
  24 struct devres {
  25         struct devres_node              node;
  26         /* -- 3 pointers */
  27         unsigned long long              data[]; /* guarantee ull alignment */
  28 };
  29
  30 struct devres_group {
  31         struct devres_node              node[2];
  32         void                            *id;
  33         int                             color;
  34         /* -- 8 pointers */
  35 };
  36
  37 #ifdef CONFIG_DEBUG_DEVRES
  38 static int log_devres = 0;
  39 module_param_named(log, log_devres, int, S_IRUGO | S_IWUSR);
  40
  41 static void set_node_dbginfo(struct devres_node *node, const char *name,
  42                              size_t size)
  43 {
  44         node->name = name;
  45         node->size = size;
  46 }
  47
  48 static void devres_log(struct device *dev, struct devres_node *node,
  49                        const char *op)
  50 {
  51         if (unlikely(log_devres))
  52                 dev_printk(KERN_ERR, dev, "DEVRES %3s %p %s (%lu bytes)\n",
  53                            op, node, node->name, (unsigned long)node->size);
  54 }
  55 #else /* CONFIG_DEBUG_DEVRES */
  56 #define set_node_dbginfo(node, n, s)    do {} while (0)
  57 #define devres_log(dev, node, op)       do {} while (0)
  58 #endif /* CONFIG_DEBUG_DEVRES */
  59
  60 /*
  61  * Release functions for devres group.  These callbacks are used only
  62  * for identification.
  63  */
  64 static void group_open_release(struct device *dev, void *res)
  65 {
  66         /* noop */
  67 }
  68
  69 static void group_close_release(struct device *dev, void *res)
  70 {
  71         /* noop */
  72 }
  73
  74 static struct devres_group * node_to_group(struct devres_node *node)
  75 {
  76         if (node->release == &group_open_release)
  77                 return container_of(node, struct devres_group, node[0]);
  78         if (node->release == &group_close_release)
  79                 return container_of(node, struct devres_group, node[1]);
  80         return NULL;
  81 }
  82
  83 static __always_inline struct devres * alloc_dr(dr_release_t release,
  84                                                 size_t size, gfp_t gfp)
  85 {
  86         size_t tot_size = sizeof(struct devres) + size;
  87         struct devres *dr;
  88
  89         dr = kmalloc_track_caller(tot_size, gfp);
  90         if (unlikely(!dr))
  91                 return NULL;
  92
  93         memset(dr, 0, tot_size);
  94         INIT_LIST_HEAD(&dr->node.entry);
  95         dr->node.release = release;
  96         return dr;
  97 }
  98
  99 static void add_dr(struct device *dev, struct devres_node *node)
 100 {
 101         devres_log(dev, node, "ADD");
 102         BUG_ON(!list_empty(&node->entry));
 103         list_add_tail(&node->entry, &dev->devres_head);
 104 }
 105
 106 #ifdef CONFIG_DEBUG_DEVRES
 107 void * __devres_alloc(dr_release_t release, size_t size, gfp_t gfp,
 108                       const char *name)
 109 {
 110         struct devres *dr;
 111
 112         dr = alloc_dr(release, size, gfp);
 113         if (unlikely(!dr))
 114                 return NULL;
 115         set_node_dbginfo(&dr->node, name, size);
 116         return dr->data;
 117 }
 118 EXPORT_SYMBOL_GPL(__devres_alloc);
 119 #else
 120 /**
 121  * devres_alloc - Allocate device resource data
 122  * @release: Release function devres will be associated with
 123  * @size: Allocation size
 124  * @gfp: Allocation flags
 125  *
 126  * Allocate devres of @size bytes.  The allocated area is zeroed, then
 127  * associated with @release.  The returned pointer can be passed to
 128  * other devres_*() functions.
 129  *
 130  * RETURNS:
 131  * Pointer to allocated devres on success, NULL on failure.
 132  */
 133 void * devres_alloc(dr_release_t release, size_t size, gfp_t gfp)
 134 {
 135         struct devres *dr;
 136
 137         dr = alloc_dr(release, size, gfp);
 138         if (unlikely(!dr))
 139                 return NULL;
 140         return dr->data;
 141 }
 142 EXPORT_SYMBOL_GPL(devres_alloc);
 143 #endif
 144
 145 /**
 146  * devres_free - Free device resource data
 147  * @res: Pointer to devres data to free
 148  *
 149  * Free devres created with devres_alloc().
 150  */
 151 void devres_free(void *res)
 152 {
 153         if (res) {
 154                 struct devres *dr = container_of(res, struct devres, data);
 155
 156                 BUG_ON(!list_empty(&dr->node.entry));
 157                 kfree(dr);
 158         }
 159 }
 160 EXPORT_SYMBOL_GPL(devres_free);
 161
 162 /**
 163  * devres_add - Register device resource
 164  * @dev: Device to add resource to
 165  * @res: Resource to register
 166  *
 167  * Register devres @res to @dev.  @res should have been allocated
 168  * using devres_alloc().  On driver detach, the associated release
 169  * function will be invoked and devres will be freed automatically.
 170  */
 171 void devres_add(struct device *dev, void *res)
 172 {
 173         struct devres *dr = container_of(res, struct devres, data);
 174         unsigned long flags;
 175
 176         spin_lock_irqsave(&dev->devres_lock, flags);
 177         add_dr(dev, &dr->node);
 178         spin_unlock_irqrestore(&dev->devres_lock, flags);
 179 }
 180 EXPORT_SYMBOL_GPL(devres_add);
 181
 182 static struct devres *find_dr(struct device *dev, dr_release_t release,
 183                               dr_match_t match, void *match_data)
 184 {
 185         struct devres_node *node;
 186
 187         list_for_each_entry_reverse(node, &dev->devres_head, entry) {
 188                 struct devres *dr = container_of(node, struct devres, node);
 189
 190                 if (node->release != release)
 191                         continue;
 192                 if (match && !match(dev, dr->data, match_data))
 193                         continue;
 194                 return dr;
 195         }
 196
 197         return NULL;
 198 }
 199
 200 /**
 201  * devres_find - Find device resource
 202  * @dev: Device to lookup resource from
 203  * @release: Look for resources associated with this release function
 204  * @match: Match function (optional)
 205  * @match_data: Data for the match function
 206  *
 207  * Find the latest devres of @dev which is associated with @release
 208  * and for which @match returns 1.  If @match is NULL, it's considered
 209  * to match all.
 210  *
 211  * RETURNS:
 212  * Pointer to found devres, NULL if not found.
 213  */
 214 void * devres_find(struct device *dev, dr_release_t release,
 215                    dr_match_t match, void *match_data)
 216 {
 217         struct devres *dr;
 218         unsigned long flags;
 219
 220         spin_lock_irqsave(&dev->devres_lock, flags);
 221         dr = find_dr(dev, release, match, match_data);
 222         spin_unlock_irqrestore(&dev->devres_lock, flags);
 223
 224         if (dr)
 225                 return dr->data;
 226         return NULL;
 227 }
 228 EXPORT_SYMBOL_GPL(devres_find);
 229
 230 /**
 231  * devres_get - Find devres, if non-existent, add one atomically
 232  * @dev: Device to lookup or add devres for
 233  * @new_res: Pointer to new initialized devres to add if not found
 234  * @match: Match function (optional)
 235  * @match_data: Data for the match function
 236  *
 237  * Find the latest devres of @dev which has the same release function
 238  * as @new_res and for which @match return 1.  If found, @new_res is
 239  * freed; otherwise, @new_res is added atomically.
 240  *
 241  * RETURNS:
 242  * Pointer to found or added devres.
 243  */
 244 void * devres_get(struct device *dev, void *new_res,
 245                   dr_match_t match, void *match_data)
 246 {
 247         struct devres *new_dr = container_of(new_res, struct devres, data);
 248         struct devres *dr;
 249         unsigned long flags;
 250
 251         spin_lock_irqsave(&dev->devres_lock, flags);
 252         dr = find_dr(dev, new_dr->node.release, match, match_data);
 253         if (!dr) {
 254                 add_dr(dev, &new_dr->node);
 255                 dr = new_dr;
 256                 new_dr = NULL;
 257         }
 258         spin_unlock_irqrestore(&dev->devres_lock, flags);
 259         devres_free(new_dr);
 260
 261         return dr->data;
 262 }
 263 EXPORT_SYMBOL_GPL(devres_get);
 264
 265 /**
 266  * devres_remove - Find a device resource and remove it
 267  * @dev: Device to find resource from
 268  * @release: Look for resources associated with this release function
 269  * @match: Match function (optional)
 270  * @match_data: Data for the match function
 271  *
 272  * Find the latest devres of @dev associated with @release and for
 273  * which @match returns 1.  If @match is NULL, it's considered to
 274  * match all.  If found, the resource is removed atomically and
 275  * returned.
 276  *
 277  * RETURNS:
 278  * Pointer to removed devres on success, NULL if not found.
 279  */
 280 void * devres_remove(struct device *dev, dr_release_t release,
 281                      dr_match_t match, void *match_data)
 282 {
 283         struct devres *dr;
 284         unsigned long flags;
 285
 286         spin_lock_irqsave(&dev->devres_lock, flags);
 287         dr = find_dr(dev, release, match, match_data);
 288         if (dr) {
 289                 list_del_init(&dr->node.entry);
 290                 devres_log(dev, &dr->node, "REM");
 291         }
 292         spin_unlock_irqrestore(&dev->devres_lock, flags);
 293
 294         if (dr)
 295                 return dr->data;
 296         return NULL;
 297 }
 298 EXPORT_SYMBOL_GPL(devres_remove);
 299
 300 /**
 301  * devres_destroy - Find a device resource and destroy it
 302  * @dev: Device to find resource from
 303  * @release: Look for resources associated with this release function
 304  * @match: Match function (optional)
 305  * @match_data: Data for the match function
 306  *
 307  * Find the latest devres of @dev associated with @release and for
 308  * which @match returns 1.  If @match is NULL, it's considered to
 309  * match all.  If found, the resource is removed atomically and freed.
 310  *
 311  * RETURNS:
 312  * 0 if devres is found and freed, -ENOENT if not found.
 313  */
 314 int devres_destroy(struct device *dev, dr_release_t release,
 315                    dr_match_t match, void *match_data)
 316 {
 317         void *res;
 318
 319         res = devres_remove(dev, release, match, match_data);
 320         if (unlikely(!res))
 321                 return -ENOENT;
 322
 323         devres_free(res);
 324         return 0;
 325 }
 326 EXPORT_SYMBOL_GPL(devres_destroy);
 327
 328 static int remove_nodes(struct device *dev,
 329                         struct list_head *first, struct list_head *end,
 330                         struct list_head *todo)
 331 {
 332         int cnt = 0, nr_groups = 0;
 333         struct list_head *cur;
 334
 335         /* First pass - move normal devres entries to @todo and clear
 336          * devres_group colors.
 337          */
 338         cur = first;
 339         while (cur != end) {
 340                 struct devres_node *node;
 341                 struct devres_group *grp;
 342
 343                 node = list_entry(cur, struct devres_node, entry);
 344                 cur = cur->next;
 345
 346                 grp = node_to_group(node);
 347                 if (grp) {
 348                         /* clear color of group markers in the first pass */
 349                         grp->color = 0;
 350                         nr_groups++;
 351                 } else {
 352                         /* regular devres entry */
 353                         if (&node->entry == first)
 354                                 first = first->next;
 355                         list_move_tail(&node->entry, todo);
 356                         cnt++;
 357                 }
 358         }
 359
 360         if (!nr_groups)
 361                 return cnt;
 362
 363         /* Second pass - Scan groups and color them.  A group gets
 364          * color value of two iff the group is wholly contained in
 365          * [cur, end).  That is, for a closed group, both opening and
 366          * closing markers should be in the range, while just the
 367          * opening marker is enough for an open group.
 368          */
 369         cur = first;
 370         while (cur != end) {
 371                 struct devres_node *node;
 372                 struct devres_group *grp;
 373
 374                 node = list_entry(cur, struct devres_node, entry);
 375                 cur = cur->next;
 376
 377                 grp = node_to_group(node);
 378                 BUG_ON(!grp || list_empty(&grp->node[0].entry));
 379
 380                 grp->color++;
 381                 if (list_empty(&grp->node[1].entry))
 382                         grp->color++;
 383
 384                 BUG_ON(grp->color <= 0 || grp->color > 2);
 385                 if (grp->color == 2) {
 386                         /* No need to update cur or end.  The removed
 387                          * nodes are always before both.
 388                          */
 389                         list_move_tail(&grp->node[0].entry, todo);
 390                         list_del_init(&grp->node[1].entry);
 391                 }
 392         }
 393
 394         return cnt;
 395 }
 396
 397 static int release_nodes(struct device *dev, struct list_head *first,
 398                          struct list_head *end, unsigned long flags)
 399 {
 400         LIST_HEAD(todo);
 401         int cnt;
 402         struct devres *dr, *tmp;
 403
 404         cnt = remove_nodes(dev, first, end, &todo);
 405
 406         spin_unlock_irqrestore(&dev->devres_lock, flags);
 407
 408         /* Release.  Note that both devres and devres_group are
 409          * handled as devres in the following loop.  This is safe.
 410          */
 411         list_for_each_entry_safe_reverse(dr, tmp, &todo, node.entry) {
 412                 devres_log(dev, &dr->node, "REL");
 413                 dr->node.release(dev, dr->data);
 414                 kfree(dr);
 415         }
 416
 417         return cnt;
 418 }
 419
 420 /**
 421  * devres_release_all - Release all managed resources
 422  * @dev: Device to release resources for
 423  *
 424  * Release all resources associated with @dev.  This function is
 425  * called on driver detach.
 426  */
 427 int devres_release_all(struct device *dev)
 428 {
 429         unsigned long flags;
 430
 431         /* Looks like an uninitialized device structure */
 432         if (WARN_ON(dev->devres_head.next == NULL))
 433                 return -ENODEV;
 434         spin_lock_irqsave(&dev->devres_lock, flags);
 435         return release_nodes(dev, dev->devres_head.next, &dev->devres_head,
 436                              flags);
 437 }
 438
 439 /**
 440  * devres_open_group - Open a new devres group
 441  * @dev: Device to open devres group for
 442  * @id: Separator ID
 443  * @gfp: Allocation flags
 444  *
 445  * Open a new devres group for @dev with @id.  For @id, using a
 446  * pointer to an object which won't be used for another group is
 447  * recommended.  If @id is NULL, address-wise unique ID is created.
 448  *
 449  * RETURNS:
 450  * ID of the new group, NULL on failure.
 451  */
 452 void * devres_open_group(struct device *dev, void *id, gfp_t gfp)
 453 {
 454         struct devres_group *grp;
 455         unsigned long flags;
 456
 457         grp = kmalloc(sizeof(*grp), gfp);
 458         if (unlikely(!grp))
 459                 return NULL;
 460
 461         grp->node[0].release = &group_open_release;
 462         grp->node[1].release = &group_close_release;
 463         INIT_LIST_HEAD(&grp->node[0].entry);
 464         INIT_LIST_HEAD(&grp->node[1].entry);
 465         set_node_dbginfo(&grp->node[0], "grp<", 0);
 466         set_node_dbginfo(&grp->node[1], "grp>", 0);
 467         grp->id = grp;
 468         if (id)
 469                 grp->id = id;
 470
 471         spin_lock_irqsave(&dev->devres_lock, flags);
 472         add_dr(dev, &grp->node[0]);
 473         spin_unlock_irqrestore(&dev->devres_lock, flags);
 474         return grp->id;
 475 }
 476 EXPORT_SYMBOL_GPL(devres_open_group);
 477
 478 /* Find devres group with ID @id.  If @id is NULL, look for the latest. */
 479 static struct devres_group * find_group(struct device *dev, void *id)
 480 {
 481         struct devres_node *node;
 482
 483         list_for_each_entry_reverse(node, &dev->devres_head, entry) {
 484                 struct devres_group *grp;
 485
 486                 if (node->release != &group_open_release)
 487                         continue;
 488
 489                 grp = container_of(node, struct devres_group, node[0]);
 490
 491                 if (id) {
 492                         if (grp->id == id)
 493                                 return grp;
 494                 } else if (list_empty(&grp->node[1].entry))
 495                         return grp;
 496         }
 497
 498         return NULL;
 499 }
 500
 501 /**
 502  * devres_close_group - Close a devres group
 503  * @dev: Device to close devres group for
 504  * @id: ID of target group, can be NULL
 505  *
 506  * Close the group identified by @id.  If @id is NULL, the latest open
 507  * group is selected.
 508  */
 509 void devres_close_group(struct device *dev, void *id)
 510 {
 511         struct devres_group *grp;
 512         unsigned long flags;
 513
 514         spin_lock_irqsave(&dev->devres_lock, flags);
 515
 516         grp = find_group(dev, id);
 517         if (grp)
 518                 add_dr(dev, &grp->node[1]);
 519         else
 520                 WARN_ON(1);
 521
 522         spin_unlock_irqrestore(&dev->devres_lock, flags);
 523 }
 524 EXPORT_SYMBOL_GPL(devres_close_group);
 525
 526 /**
 527  * devres_remove_group - Remove a devres group
 528  * @dev: Device to remove group for
 529  * @id: ID of target group, can be NULL
 530  *
 531  * Remove the group identified by @id.  If @id is NULL, the latest
 532  * open group is selected.  Note that removing a group doesn't affect
 533  * any other resources.
 534  */
 535 void devres_remove_group(struct device *dev, void *id)
 536 {
 537         struct devres_group *grp;
 538         unsigned long flags;
 539
 540         spin_lock_irqsave(&dev->devres_lock, flags);
 541
 542         grp = find_group(dev, id);
 543         if (grp) {
 544                 list_del_init(&grp->node[0].entry);
 545                 list_del_init(&grp->node[1].entry);
 546                 devres_log(dev, &grp->node[0], "REM");
 547         } else
 548                 WARN_ON(1);
 549
 550         spin_unlock_irqrestore(&dev->devres_lock, flags);
 551
 552         kfree(grp);
 553 }
 554 EXPORT_SYMBOL_GPL(devres_remove_group);
 555
 556 /**
 557  * devres_release_group - Release resources in a devres group
 558  * @dev: Device to release group for
 559  * @id: ID of target group, can be NULL
 560  *
 561  * Release all resources in the group identified by @id.  If @id is
 562  * NULL, the latest open group is selected.  The selected group and
 563  * groups properly nested inside the selected group are removed.
 564  *
 565  * RETURNS:
 566  * The number of released non-group resources.
 567  */
 568 int devres_release_group(struct device *dev, void *id)
 569 {
 570         struct devres_group *grp;
 571         unsigned long flags;
 572         int cnt = 0;
 573
 574         spin_lock_irqsave(&dev->devres_lock, flags);
 575
 576         grp = find_group(dev, id);
 577         if (grp) {
 578                 struct list_head *first = &grp->node[0].entry;
 579                 struct list_head *end = &dev->devres_head;
 580
 581                 if (!list_empty(&grp->node[1].entry))
 582                         end = grp->node[1].entry.next;
 583
 584                 cnt = release_nodes(dev, first, end, flags);
 585         } else {
 586                 WARN_ON(1);
 587                 spin_unlock_irqrestore(&dev->devres_lock, flags);
 588         }
 589
 590         return cnt;
 591 }
 592 EXPORT_SYMBOL_GPL(devres_release_group);
 593
 594 /*
 595  * Managed kzalloc/kfree
 596  */
 597 static void devm_kzalloc_release(struct device *dev, void *res)
 598 {
 599         /* noop */
 600 }
 601
 602 static int devm_kzalloc_match(struct device *dev, void *res, void *data)
 603 {
 604         return res == data;
 605 }
 606
 607 /**
 608  * devm_kzalloc - Resource-managed kzalloc
 609  * @dev: Device to allocate memory for
 610  * @size: Allocation size
 611  * @gfp: Allocation gfp flags
 612  *
 613  * Managed kzalloc.  Memory allocated with this function is
 614  * automatically freed on driver detach.  Like all other devres
 615  * resources, guaranteed alignment is unsigned long long.
 616  *
 617  * RETURNS:
 618  * Pointer to allocated memory on success, NULL on failure.
 619  */
 620 void * devm_kzalloc(struct device *dev, size_t size, gfp_t gfp)
 621 {
 622         struct devres *dr;
 623
 624         /* use raw alloc_dr for kmalloc caller tracing */
 625         dr = alloc_dr(devm_kzalloc_release, size, gfp);
 626         if (unlikely(!dr))
 627                 return NULL;
 628
 629         set_node_dbginfo(&dr->node, "devm_kzalloc_release", size);
 630         devres_add(dev, dr->data);
 631         return dr->data;
 632 }
 633 EXPORT_SYMBOL_GPL(devm_kzalloc);
 634
 635 /**
 636  * devm_kfree - Resource-managed kfree
 637  * @dev: Device this memory belongs to
 638  * @p: Memory to free
 639  *
 640  * Free memory allocated with dev_kzalloc().
 641  */
 642 void devm_kfree(struct device *dev, void *p)
 643 {
 644         int rc;
 645
 646         rc = devres_destroy(dev, devm_kzalloc_release, devm_kzalloc_match, p);
 647         WARN_ON(rc);
 648 }
 649 EXPORT_SYMBOL_GPL(devm_kfree);