drivers/gpu/drm/drm_stub.c

   1 /**
   2  * \file drm_stub.h
   3  * Stub support
   4  *
   5  * \author Rickard E. (Rik) Faith <faith@valinux.com>
   6  */
   7
   8 /*
   9  * Created: Fri Jan 19 10:48:35 2001 by faith@acm.org
  10  *
  11  * Copyright 2001 VA Linux Systems, Inc., Sunnyvale, California.
  12  * All Rights Reserved.
  13  *
  14  * Permission is hereby granted, free of charge, to any person obtaining a
  15  * copy of this software and associated documentation files (the "Software"),
  16  * to deal in the Software without restriction, including without limitation
  17  * the rights to use, copy, modify, merge, publish, distribute, sublicense,
  18  * and/or sell copies of the Software, and to permit persons to whom the
  19  * Software is furnished to do so, subject to the following conditions:
  20  *
  21  * The above copyright notice and this permission notice (including the next
  22  * paragraph) shall be included in all copies or substantial portions of the
  23  * Software.
  24  *
  25  * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
  26  * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
  27  * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.  IN NO EVENT SHALL
  28  * PRECISION INSIGHT AND/OR ITS SUPPLIERS BE LIABLE FOR ANY CLAIM, DAMAGES OR
  29  * OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE,
  30  * ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
  31  * DEALINGS IN THE SOFTWARE.
  32  */
  33
  34 #include <linux/fs.h>
  35 #include <linux/module.h>
  36 #include <linux/moduleparam.h>
  37 #include <linux/mount.h>
  38 #include <linux/slab.h>
  39 #include <drm/drmP.h>
  40 #include <drm/drm_core.h>
  41
  42 unsigned int drm_debug = 0;     /* 1 to enable debug output */
  43 EXPORT_SYMBOL(drm_debug);
  44
  45 unsigned int drm_rnodes = 0;    /* 1 to enable experimental render nodes API */
  46 EXPORT_SYMBOL(drm_rnodes);
  47
  48 unsigned int drm_vblank_offdelay = 5000;    /* Default to 5000 msecs. */
  49 EXPORT_SYMBOL(drm_vblank_offdelay);
  50
  51 unsigned int drm_timestamp_precision = 20;  /* Default to 20 usecs. */
  52 EXPORT_SYMBOL(drm_timestamp_precision);
  53
  54 /*
  55  * Default to use monotonic timestamps for wait-for-vblank and page-flip
  56  * complete events.
  57  */
  58 unsigned int drm_timestamp_monotonic = 1;
  59
  60 MODULE_AUTHOR(CORE_AUTHOR);
  61 MODULE_DESCRIPTION(CORE_DESC);
  62 MODULE_LICENSE("GPL and additional rights");
  63 MODULE_PARM_DESC(debug, "Enable debug output");
  64 MODULE_PARM_DESC(rnodes, "Enable experimental render nodes API");
  65 MODULE_PARM_DESC(vblankoffdelay, "Delay until vblank irq auto-disable [msecs]");
  66 MODULE_PARM_DESC(timestamp_precision_usec, "Max. error on timestamps [usecs]");
  67 MODULE_PARM_DESC(timestamp_monotonic, "Use monotonic timestamps");
  68
  69 module_param_named(debug, drm_debug, int, 0600);
  70 module_param_named(rnodes, drm_rnodes, int, 0600);
  71 module_param_named(vblankoffdelay, drm_vblank_offdelay, int, 0600);
  72 module_param_named(timestamp_precision_usec, drm_timestamp_precision, int, 0600);
  73 module_param_named(timestamp_monotonic, drm_timestamp_monotonic, int, 0600);
  74
  75 static DEFINE_SPINLOCK(drm_minor_lock);
  76 struct idr drm_minors_idr;
  77
  78 struct class *drm_class;
  79 struct dentry *drm_debugfs_root;
  80
  81 int drm_err(const char *func, const char *format, ...)
  82 {
  83         struct va_format vaf;
  84         va_list args;
  85         int r;
  86
  87         va_start(args, format);
  88
  89         vaf.fmt = format;
  90         vaf.va = &args;
  91
  92         r = printk(KERN_ERR "[" DRM_NAME ":%s] *ERROR* %pV", func, &vaf);
  93
  94         va_end(args);
  95
  96         return r;
  97 }
  98 EXPORT_SYMBOL(drm_err);
  99
 100 void drm_ut_debug_printk(unsigned int request_level,
 101                          const char *prefix,
 102                          const char *function_name,
 103                          const char *format, ...)
 104 {
 105         struct va_format vaf;
 106         va_list args;
 107
 108         if (drm_debug & request_level) {
 109                 va_start(args, format);
 110                 vaf.fmt = format;
 111                 vaf.va = &args;
 112
 113                 if (function_name)
 114                         printk(KERN_DEBUG "[%s:%s], %pV", prefix,
 115                                function_name, &vaf);
 116                 else
 117                         printk(KERN_DEBUG "%pV", &vaf);
 118                 va_end(args);
 119         }
 120 }
 121 EXPORT_SYMBOL(drm_ut_debug_printk);
 122
 123 struct drm_master *drm_master_create(struct drm_minor *minor)
 124 {
 125         struct drm_master *master;
 126
 127         master = kzalloc(sizeof(*master), GFP_KERNEL);
 128         if (!master)
 129                 return NULL;
 130
 131         kref_init(&master->refcount);
 132         spin_lock_init(&master->lock.spinlock);
 133         init_waitqueue_head(&master->lock.lock_queue);
 134         drm_ht_create(&master->magiclist, DRM_MAGIC_HASH_ORDER);
 135         INIT_LIST_HEAD(&master->magicfree);
 136         master->minor = minor;
 137
 138         list_add_tail(&master->head, &minor->master_list);
 139
 140         return master;
 141 }
 142
 143 struct drm_master *drm_master_get(struct drm_master *master)
 144 {
 145         kref_get(&master->refcount);
 146         return master;
 147 }
 148 EXPORT_SYMBOL(drm_master_get);
 149
 150 static void drm_master_destroy(struct kref *kref)
 151 {
 152         struct drm_master *master = container_of(kref, struct drm_master, refcount);
 153         struct drm_magic_entry *pt, *next;
 154         struct drm_device *dev = master->minor->dev;
 155         struct drm_map_list *r_list, *list_temp;
 156
 157         list_del(&master->head);
 158
 159         if (dev->driver->master_destroy)
 160                 dev->driver->master_destroy(dev, master);
 161
 162         list_for_each_entry_safe(r_list, list_temp, &dev->maplist, head) {
 163                 if (r_list->master == master) {
 164                         drm_rmmap_locked(dev, r_list->map);
 165                         r_list = NULL;
 166                 }
 167         }
 168
 169         if (master->unique) {
 170                 kfree(master->unique);
 171                 master->unique = NULL;
 172                 master->unique_len = 0;
 173         }
 174
 175         kfree(dev->devname);
 176         dev->devname = NULL;
 177
 178         list_for_each_entry_safe(pt, next, &master->magicfree, head) {
 179                 list_del(&pt->head);
 180                 drm_ht_remove_item(&master->magiclist, &pt->hash_item);
 181                 kfree(pt);
 182         }
 183
 184         drm_ht_remove(&master->magiclist);
 185
 186         kfree(master);
 187 }
 188
 189 void drm_master_put(struct drm_master **master)
 190 {
 191         kref_put(&(*master)->refcount, drm_master_destroy);
 192         *master = NULL;
 193 }
 194 EXPORT_SYMBOL(drm_master_put);
 195
 196 int drm_setmaster_ioctl(struct drm_device *dev, void *data,
 197                         struct drm_file *file_priv)
 198 {
 199         int ret = 0;
 200
 201         if (file_priv->is_master)
 202                 return 0;
 203
 204         if (file_priv->minor->master && file_priv->minor->master != file_priv->master)
 205                 return -EINVAL;
 206
 207         if (!file_priv->master)
 208                 return -EINVAL;
 209
 210         if (file_priv->minor->master)
 211                 return -EINVAL;
 212
 213         mutex_lock(&dev->struct_mutex);
 214         file_priv->minor->master = drm_master_get(file_priv->master);
 215         file_priv->is_master = 1;
 216         if (dev->driver->master_set) {
 217                 ret = dev->driver->master_set(dev, file_priv, false);
 218                 if (unlikely(ret != 0)) {
 219                         file_priv->is_master = 0;
 220                         drm_master_put(&file_priv->minor->master);
 221                 }
 222         }
 223         mutex_unlock(&dev->struct_mutex);
 224
 225         return ret;
 226 }
 227
 228 int drm_dropmaster_ioctl(struct drm_device *dev, void *data,
 229                          struct drm_file *file_priv)
 230 {
 231         if (!file_priv->is_master)
 232                 return -EINVAL;
 233
 234         if (!file_priv->minor->master)
 235                 return -EINVAL;
 236
 237         mutex_lock(&dev->struct_mutex);
 238         if (dev->driver->master_drop)
 239                 dev->driver->master_drop(dev, file_priv, false);
 240         drm_master_put(&file_priv->minor->master);
 241         file_priv->is_master = 0;
 242         mutex_unlock(&dev->struct_mutex);
 243         return 0;
 244 }
 245
 246 /*
 247  * DRM Minors
 248  * A DRM device can provide several char-dev interfaces on the DRM-Major. Each
 249  * of them is represented by a drm_minor object. Depending on the capabilities
 250  * of the device-driver, different interfaces are registered.
 251  *
 252  * Minors can be accessed via dev->$minor_name. This pointer is either
 253  * NULL or a valid drm_minor pointer and stays valid as long as the device is
 254  * valid. This means, DRM minors have the same life-time as the underlying
 255  * device. However, this doesn't mean that the minor is active. Minors are
 256  * registered and unregistered dynamically according to device-state.
 257  */
 258
 259 static struct drm_minor **drm_minor_get_slot(struct drm_device *dev,
 260                                              unsigned int type)
 261 {
 262         switch (type) {
 263         case DRM_MINOR_LEGACY:
 264                 return &dev->primary;
 265         case DRM_MINOR_RENDER:
 266                 return &dev->render;
 267         case DRM_MINOR_CONTROL:
 268                 return &dev->control;
 269         default:
 270                 return NULL;
 271         }
 272 }
 273
 274 static int drm_minor_alloc(struct drm_device *dev, unsigned int type)
 275 {
 276         struct drm_minor *minor;
 277
 278         minor = kzalloc(sizeof(*minor), GFP_KERNEL);
 279         if (!minor)
 280                 return -ENOMEM;
 281
 282         minor->type = type;
 283         minor->dev = dev;
 284         INIT_LIST_HEAD(&minor->master_list);
 285
 286         *drm_minor_get_slot(dev, type) = minor;
 287         return 0;
 288 }
 289
 290 static void drm_minor_free(struct drm_device *dev, unsigned int type)
 291 {
 292         struct drm_minor **slot;
 293
 294         slot = drm_minor_get_slot(dev, type);
 295         if (*slot) {
 296                 kfree(*slot);
 297                 *slot = NULL;
 298         }
 299 }
 300
 301 static int drm_minor_register(struct drm_device *dev, unsigned int type)
 302 {
 303         struct drm_minor *new_minor;
 304         unsigned long flags;
 305         int ret;
 306         int minor_id;
 307
 308         DRM_DEBUG("\n");
 309
 310         new_minor = *drm_minor_get_slot(dev, type);
 311         if (!new_minor)
 312                 return 0;
 313
 314         idr_preload(GFP_KERNEL);
 315         spin_lock_irqsave(&drm_minor_lock, flags);
 316         minor_id = idr_alloc(&drm_minors_idr,
 317                              NULL,
 318                              64 * type,
 319                              64 * (type + 1),
 320                              GFP_NOWAIT);
 321         spin_unlock_irqrestore(&drm_minor_lock, flags);
 322         idr_preload_end();
 323
 324         if (minor_id < 0)
 325                 return minor_id;
 326
 327         new_minor->index = minor_id;
 328
 329         ret = drm_debugfs_init(new_minor, minor_id, drm_debugfs_root);
 330         if (ret) {
 331                 DRM_ERROR("DRM: Failed to initialize /sys/kernel/debug/dri.\n");
 332                 goto err_id;
 333         }
 334
 335         ret = drm_sysfs_device_add(new_minor);
 336         if (ret) {
 337                 DRM_ERROR("DRM: Error sysfs_device_add.\n");
 338                 goto err_debugfs;
 339         }
 340
 341         /* replace NULL with @minor so lookups will succeed from now on */
 342         spin_lock_irqsave(&drm_minor_lock, flags);
 343         idr_replace(&drm_minors_idr, new_minor, new_minor->index);
 344         spin_unlock_irqrestore(&drm_minor_lock, flags);
 345
 346         DRM_DEBUG("new minor assigned %d\n", minor_id);
 347         return 0;
 348
 349 err_debugfs:
 350         drm_debugfs_cleanup(new_minor);
 351 err_id:
 352         spin_lock_irqsave(&drm_minor_lock, flags);
 353         idr_remove(&drm_minors_idr, minor_id);
 354         spin_unlock_irqrestore(&drm_minor_lock, flags);
 355         new_minor->index = 0;
 356         return ret;
 357 }
 358
 359 static void drm_minor_unregister(struct drm_device *dev, unsigned int type)
 360 {
 361         struct drm_minor *minor;
 362         unsigned long flags;
 363
 364         minor = *drm_minor_get_slot(dev, type);
 365         if (!minor || !minor->kdev)
 366                 return;
 367
 368         spin_lock_irqsave(&drm_minor_lock, flags);
 369         idr_remove(&drm_minors_idr, minor->index);
 370         spin_unlock_irqrestore(&drm_minor_lock, flags);
 371         minor->index = 0;
 372
 373         drm_debugfs_cleanup(minor);
 374         drm_sysfs_device_remove(minor);
 375 }
 376
 377 /**
 378  * drm_minor_acquire - Acquire a DRM minor
 379  * @minor_id: Minor ID of the DRM-minor
 380  *
 381  * Looks up the given minor-ID and returns the respective DRM-minor object. The
 382  * refence-count of the underlying device is increased so you must release this
 383  * object with drm_minor_release().
 384  *
 385  * As long as you hold this minor, it is guaranteed that the object and the
 386  * minor->dev pointer will stay valid! However, the device may get unplugged and
 387  * unregistered while you hold the minor.
 388  *
 389  * Returns:
 390  * Pointer to minor-object with increased device-refcount, or PTR_ERR on
 391  * failure.
 392  */
 393 struct drm_minor *drm_minor_acquire(unsigned int minor_id)
 394 {
 395         struct drm_minor *minor;
 396         unsigned long flags;
 397
 398         spin_lock_irqsave(&drm_minor_lock, flags);
 399         minor = idr_find(&drm_minors_idr, minor_id);
 400         if (minor)
 401                 drm_dev_ref(minor->dev);
 402         spin_unlock_irqrestore(&drm_minor_lock, flags);
 403
 404         if (!minor) {
 405                 return ERR_PTR(-ENODEV);
 406         } else if (drm_device_is_unplugged(minor->dev)) {
 407                 drm_dev_unref(minor->dev);
 408                 return ERR_PTR(-ENODEV);
 409         }
 410
 411         return minor;
 412 }
 413
 414 /**
 415  * drm_minor_release - Release DRM minor
 416  * @minor: Pointer to DRM minor object
 417  *
 418  * Release a minor that was previously acquired via drm_minor_acquire().
 419  */
 420 void drm_minor_release(struct drm_minor *minor)
 421 {
 422         drm_dev_unref(minor->dev);
 423 }
 424
 425 /**
 426  * Called via drm_exit() at module unload time or when pci device is
 427  * unplugged.
 428  *
 429  * Cleans up all DRM device, calling drm_lastclose().
 430  *
 431  */
 432 void drm_put_dev(struct drm_device *dev)
 433 {
 434         DRM_DEBUG("\n");
 435
 436         if (!dev) {
 437                 DRM_ERROR("cleanup called no dev\n");
 438                 return;
 439         }
 440
 441         drm_dev_unregister(dev);
 442         drm_dev_unref(dev);
 443 }
 444 EXPORT_SYMBOL(drm_put_dev);
 445
 446 void drm_unplug_dev(struct drm_device *dev)
 447 {
 448         /* for a USB device */
 449         drm_minor_unregister(dev, DRM_MINOR_LEGACY);
 450         drm_minor_unregister(dev, DRM_MINOR_RENDER);
 451         drm_minor_unregister(dev, DRM_MINOR_CONTROL);
 452
 453         mutex_lock(&drm_global_mutex);
 454
 455         drm_device_set_unplugged(dev);
 456
 457         if (dev->open_count == 0) {
 458                 drm_put_dev(dev);
 459         }
 460         mutex_unlock(&drm_global_mutex);
 461 }
 462 EXPORT_SYMBOL(drm_unplug_dev);
 463
 464 /*
 465  * DRM internal mount
 466  * We want to be able to allocate our own "struct address_space" to control
 467  * memory-mappings in VRAM (or stolen RAM, ...). However, core MM does not allow
 468  * stand-alone address_space objects, so we need an underlying inode. As there
 469  * is no way to allocate an independent inode easily, we need a fake internal
 470  * VFS mount-point.
 471  *
 472  * The drm_fs_inode_new() function allocates a new inode, drm_fs_inode_free()
 473  * frees it again. You are allowed to use iget() and iput() to get references to
 474  * the inode. But each drm_fs_inode_new() call must be paired with exactly one
 475  * drm_fs_inode_free() call (which does not have to be the last iput()).
 476  * We use drm_fs_inode_*() to manage our internal VFS mount-point and share it
 477  * between multiple inode-users. You could, technically, call
 478  * iget() + drm_fs_inode_free() directly after alloc and sometime later do an
 479  * iput(), but this way you'd end up with a new vfsmount for each inode.
 480  */
 481
 482 static int drm_fs_cnt;
 483 static struct vfsmount *drm_fs_mnt;
 484
 485 static const struct dentry_operations drm_fs_dops = {
 486         .d_dname        = simple_dname,
 487 };
 488
 489 static const struct super_operations drm_fs_sops = {
 490         .statfs         = simple_statfs,
 491 };
 492
 493 static struct dentry *drm_fs_mount(struct file_system_type *fs_type, int flags,
 494                                    const char *dev_name, void *data)
 495 {
 496         return mount_pseudo(fs_type,
 497                             "drm:",
 498                             &drm_fs_sops,
 499                             &drm_fs_dops,
 500                             0x010203ff);
 501 }
 502
 503 static struct file_system_type drm_fs_type = {
 504         .name           = "drm",
 505         .owner          = THIS_MODULE,
 506         .mount          = drm_fs_mount,
 507         .kill_sb        = kill_anon_super,
 508 };
 509
 510 static struct inode *drm_fs_inode_new(void)
 511 {
 512         struct inode *inode;
 513         int r;
 514
 515         r = simple_pin_fs(&drm_fs_type, &drm_fs_mnt, &drm_fs_cnt);
 516         if (r < 0) {
 517                 DRM_ERROR("Cannot mount pseudo fs: %d\n", r);
 518                 return ERR_PTR(r);
 519         }
 520
 521         inode = alloc_anon_inode(drm_fs_mnt->mnt_sb);
 522         if (IS_ERR(inode))
 523                 simple_release_fs(&drm_fs_mnt, &drm_fs_cnt);
 524
 525         return inode;
 526 }
 527
 528 static void drm_fs_inode_free(struct inode *inode)
 529 {
 530         if (inode) {
 531                 iput(inode);
 532                 simple_release_fs(&drm_fs_mnt, &drm_fs_cnt);
 533         }
 534 }
 535
 536 /**
 537  * drm_dev_alloc - Allocate new drm device
 538  * @driver: DRM driver to allocate device for
 539  * @parent: Parent device object
 540  *
 541  * Allocate and initialize a new DRM device. No device registration is done.
 542  * Call drm_dev_register() to advertice the device to user space and register it
 543  * with other core subsystems.
 544  *
 545  * The initial ref-count of the object is 1. Use drm_dev_ref() and
 546  * drm_dev_unref() to take and drop further ref-counts.
 547  *
 548  * RETURNS:
 549  * Pointer to new DRM device, or NULL if out of memory.
 550  */
 551 struct drm_device *drm_dev_alloc(struct drm_driver *driver,
 552                                  struct device *parent)
 553 {
 554         struct drm_device *dev;
 555         int ret;
 556
 557         dev = kzalloc(sizeof(*dev), GFP_KERNEL);
 558         if (!dev)
 559                 return NULL;
 560
 561         kref_init(&dev->ref);
 562         dev->dev = parent;
 563         dev->driver = driver;
 564
 565         INIT_LIST_HEAD(&dev->filelist);
 566         INIT_LIST_HEAD(&dev->ctxlist);
 567         INIT_LIST_HEAD(&dev->vmalist);
 568         INIT_LIST_HEAD(&dev->maplist);
 569         INIT_LIST_HEAD(&dev->vblank_event_list);
 570
 571         spin_lock_init(&dev->count_lock);
 572         spin_lock_init(&dev->event_lock);
 573         mutex_init(&dev->struct_mutex);
 574         mutex_init(&dev->ctxlist_mutex);
 575
 576         dev->anon_inode = drm_fs_inode_new();
 577         if (IS_ERR(dev->anon_inode)) {
 578                 ret = PTR_ERR(dev->anon_inode);
 579                 DRM_ERROR("Cannot allocate anonymous inode: %d\n", ret);
 580                 goto err_free;
 581         }
 582
 583         if (drm_core_check_feature(dev, DRIVER_MODESET)) {
 584                 ret = drm_minor_alloc(dev, DRM_MINOR_CONTROL);
 585                 if (ret)
 586                         goto err_minors;
 587         }
 588
 589         if (drm_core_check_feature(dev, DRIVER_RENDER) && drm_rnodes) {
 590                 ret = drm_minor_alloc(dev, DRM_MINOR_RENDER);
 591                 if (ret)
 592                         goto err_minors;
 593         }
 594
 595         ret = drm_minor_alloc(dev, DRM_MINOR_LEGACY);
 596         if (ret)
 597                 goto err_minors;
 598
 599         if (drm_ht_create(&dev->map_hash, 12))
 600                 goto err_minors;
 601
 602         ret = drm_ctxbitmap_init(dev);
 603         if (ret) {
 604                 DRM_ERROR("Cannot allocate memory for context bitmap.\n");
 605                 goto err_ht;
 606         }
 607
 608         if (driver->driver_features & DRIVER_GEM) {
 609                 ret = drm_gem_init(dev);
 610                 if (ret) {
 611                         DRM_ERROR("Cannot initialize graphics execution manager (GEM)\n");
 612                         goto err_ctxbitmap;
 613                 }
 614         }
 615
 616         return dev;
 617
 618 err_ctxbitmap:
 619         drm_ctxbitmap_cleanup(dev);
 620 err_ht:
 621         drm_ht_remove(&dev->map_hash);
 622 err_minors:
 623         drm_minor_free(dev, DRM_MINOR_LEGACY);
 624         drm_minor_free(dev, DRM_MINOR_RENDER);
 625         drm_minor_free(dev, DRM_MINOR_CONTROL);
 626         drm_fs_inode_free(dev->anon_inode);
 627 err_free:
 628         kfree(dev);
 629         return NULL;
 630 }
 631 EXPORT_SYMBOL(drm_dev_alloc);
 632
 633 static void drm_dev_release(struct kref *ref)
 634 {
 635         struct drm_device *dev = container_of(ref, struct drm_device, ref);
 636
 637         if (dev->driver->driver_features & DRIVER_GEM)
 638                 drm_gem_destroy(dev);
 639
 640         drm_ctxbitmap_cleanup(dev);
 641         drm_ht_remove(&dev->map_hash);
 642         drm_fs_inode_free(dev->anon_inode);
 643
 644         drm_minor_free(dev, DRM_MINOR_LEGACY);
 645         drm_minor_free(dev, DRM_MINOR_RENDER);
 646         drm_minor_free(dev, DRM_MINOR_CONTROL);
 647
 648         kfree(dev->devname);
 649         kfree(dev);
 650 }
 651
 652 /**
 653  * drm_dev_ref - Take reference of a DRM device
 654  * @dev: device to take reference of or NULL
 655  *
 656  * This increases the ref-count of @dev by one. You *must* already own a
 657  * reference when calling this. Use drm_dev_unref() to drop this reference
 658  * again.
 659  *
 660  * This function never fails. However, this function does not provide *any*
 661  * guarantee whether the device is alive or running. It only provides a
 662  * reference to the object and the memory associated with it.
 663  */
 664 void drm_dev_ref(struct drm_device *dev)
 665 {
 666         if (dev)
 667                 kref_get(&dev->ref);
 668 }
 669 EXPORT_SYMBOL(drm_dev_ref);
 670
 671 /**
 672  * drm_dev_unref - Drop reference of a DRM device
 673  * @dev: device to drop reference of or NULL
 674  *
 675  * This decreases the ref-count of @dev by one. The device is destroyed if the
 676  * ref-count drops to zero.
 677  */
 678 void drm_dev_unref(struct drm_device *dev)
 679 {
 680         if (dev)
 681                 kref_put(&dev->ref, drm_dev_release);
 682 }
 683 EXPORT_SYMBOL(drm_dev_unref);
 684
 685 /**
 686  * drm_dev_register - Register DRM device
 687  * @dev: Device to register
 688  *
 689  * Register the DRM device @dev with the system, advertise device to user-space
 690  * and start normal device operation. @dev must be allocated via drm_dev_alloc()
 691  * previously.
 692  *
 693  * Never call this twice on any device!
 694  *
 695  * RETURNS:
 696  * 0 on success, negative error code on failure.
 697  */
 698 int drm_dev_register(struct drm_device *dev, unsigned long flags)
 699 {
 700         int ret;
 701
 702         mutex_lock(&drm_global_mutex);
 703
 704         ret = drm_minor_register(dev, DRM_MINOR_CONTROL);
 705         if (ret)
 706                 goto err_minors;
 707
 708         ret = drm_minor_register(dev, DRM_MINOR_RENDER);
 709         if (ret)
 710                 goto err_minors;
 711
 712         ret = drm_minor_register(dev, DRM_MINOR_LEGACY);
 713         if (ret)
 714                 goto err_minors;
 715
 716         if (dev->driver->load) {
 717                 ret = dev->driver->load(dev, flags);
 718                 if (ret)
 719                         goto err_minors;
 720         }
 721
 722         /* setup grouping for legacy outputs */
 723         if (drm_core_check_feature(dev, DRIVER_MODESET)) {
 724                 ret = drm_mode_group_init_legacy_group(dev,
 725                                 &dev->primary->mode_group);
 726                 if (ret)
 727                         goto err_unload;
 728         }
 729
 730         ret = 0;
 731         goto out_unlock;
 732
 733 err_unload:
 734         if (dev->driver->unload)
 735                 dev->driver->unload(dev);
 736 err_minors:
 737         drm_minor_unregister(dev, DRM_MINOR_LEGACY);
 738         drm_minor_unregister(dev, DRM_MINOR_RENDER);
 739         drm_minor_unregister(dev, DRM_MINOR_CONTROL);
 740 out_unlock:
 741         mutex_unlock(&drm_global_mutex);
 742         return ret;
 743 }
 744 EXPORT_SYMBOL(drm_dev_register);
 745
 746 /**
 747  * drm_dev_unregister - Unregister DRM device
 748  * @dev: Device to unregister
 749  *
 750  * Unregister the DRM device from the system. This does the reverse of
 751  * drm_dev_register() but does not deallocate the device. The caller must call
 752  * drm_dev_unref() to drop their final reference.
 753  */
 754 void drm_dev_unregister(struct drm_device *dev)
 755 {
 756         struct drm_map_list *r_list, *list_temp;
 757
 758         drm_lastclose(dev);
 759
 760         if (dev->driver->unload)
 761                 dev->driver->unload(dev);
 762
 763         if (dev->agp)
 764                 drm_pci_agp_destroy(dev);
 765
 766         drm_vblank_cleanup(dev);
 767
 768         list_for_each_entry_safe(r_list, list_temp, &dev->maplist, head)
 769                 drm_rmmap(dev, r_list->map);
 770
 771         drm_minor_unregister(dev, DRM_MINOR_LEGACY);
 772         drm_minor_unregister(dev, DRM_MINOR_RENDER);
 773         drm_minor_unregister(dev, DRM_MINOR_CONTROL);
 774 }
 775 EXPORT_SYMBOL(drm_dev_unregister);