1 /*
2 * Created: Fri Jan 19 10:48:35 2001 by faith@acm.org
3 *
4 * Copyright 2001 VA Linux Systems, Inc., Sunnyvale, California.
5 * All Rights Reserved.
6 *
7 * Author Rickard E. (Rik) Faith <faith@valinux.com>
8 *
9 * Permission is hereby granted, free of charge, to any person obtaining a
10 * copy of this software and associated documentation files (the "Software"),
11 * to deal in the Software without restriction, including without limitation
12 * the rights to use, copy, modify, merge, publish, distribute, sublicense,
13 * and/or sell copies of the Software, and to permit persons to whom the
14 * Software is furnished to do so, subject to the following conditions:
15 *
16 * The above copyright notice and this permission notice (including the next
17 * paragraph) shall be included in all copies or substantial portions of the
18 * Software.
19 *
20 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
21 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
22 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
23 * PRECISION INSIGHT AND/OR ITS SUPPLIERS BE LIABLE FOR ANY CLAIM, DAMAGES OR
24 * OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE,
25 * ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
26 * DEALINGS IN THE SOFTWARE.
27 */
28
29 #include <linux/debugfs.h>
30 #include <linux/fs.h>
31 #include <linux/module.h>
32 #include <linux/moduleparam.h>
33 #include <linux/mount.h>
34 #include <linux/pseudo_fs.h>
35 #include <linux/slab.h>
36 #include <linux/srcu.h>
37
38 #include <drm/drm_client.h>
39 #include <drm/drm_color_mgmt.h>
40 #include <drm/drm_drv.h>
41 #include <drm/drm_file.h>
42 #include <drm/drm_managed.h>
43 #include <drm/drm_mode_object.h>
44 #include <drm/drm_print.h>
45
46 #include "drm_crtc_internal.h"
47 #include "drm_internal.h"
48 #include "drm_legacy.h"
49
50 MODULE_AUTHOR("Gareth Hughes, Leif Delgass, José Fonseca, Jon Smirl");
51 MODULE_DESCRIPTION("DRM shared core routines");
52 MODULE_LICENSE("GPL and additional rights");
53
54 static DEFINE_SPINLOCK(drm_minor_lock);
55 static struct idr drm_minors_idr;
56
57 /*
58 * If the drm core fails to init for whatever reason,
59 * we should prevent any drivers from registering with it.
60 * It's best to check this at drm_dev_init(), as some drivers
61 * prefer to embed struct drm_device into their own device
62 * structure and call drm_dev_init() themselves.
63 */
64 static bool drm_core_init_complete;
65
66 static struct dentry *drm_debugfs_root;
67
68 DEFINE_STATIC_SRCU(drm_unplug_srcu);
69
70 /*
71 * DRM Minors
72 * A DRM device can provide several char-dev interfaces on the DRM-Major. Each
73 * of them is represented by a drm_minor object. Depending on the capabilities
74 * of the device-driver, different interfaces are registered.
75 *
76 * Minors can be accessed via dev->$minor_name. This pointer is either
77 * NULL or a valid drm_minor pointer and stays valid as long as the device is
78 * valid. This means, DRM minors have the same life-time as the underlying
79 * device. However, this doesn't mean that the minor is active. Minors are
80 * registered and unregistered dynamically according to device-state.
81 */
82
drm_minor_get_slot(struct drm_device * dev,unsigned int type)83 static struct drm_minor **drm_minor_get_slot(struct drm_device *dev,
84 unsigned int type)
85 {
86 switch (type) {
87 case DRM_MINOR_PRIMARY:
88 return &dev->primary;
89 case DRM_MINOR_RENDER:
90 return &dev->render;
91 default:
92 BUG();
93 }
94 }
95
drm_minor_alloc_release(struct drm_device * dev,void * data)96 static void drm_minor_alloc_release(struct drm_device *dev, void *data)
97 {
98 struct drm_minor *minor = data;
99 unsigned long flags;
100
101 WARN_ON(dev != minor->dev);
102
103 put_device(minor->kdev);
104
105 spin_lock_irqsave(&drm_minor_lock, flags);
106 idr_remove(&drm_minors_idr, minor->index);
107 spin_unlock_irqrestore(&drm_minor_lock, flags);
108 }
109
drm_minor_alloc(struct drm_device * dev,unsigned int type)110 static int drm_minor_alloc(struct drm_device *dev, unsigned int type)
111 {
112 struct drm_minor *minor;
113 unsigned long flags;
114 int r;
115
116 minor = drmm_kzalloc(dev, sizeof(*minor), GFP_KERNEL);
117 if (!minor)
118 return -ENOMEM;
119
120 minor->type = type;
121 minor->dev = dev;
122
123 idr_preload(GFP_KERNEL);
124 spin_lock_irqsave(&drm_minor_lock, flags);
125 r = idr_alloc(&drm_minors_idr,
126 NULL,
127 64 * type,
128 64 * (type + 1),
129 GFP_NOWAIT);
130 spin_unlock_irqrestore(&drm_minor_lock, flags);
131 idr_preload_end();
132
133 if (r < 0)
134 return r;
135
136 minor->index = r;
137
138 r = drmm_add_action_or_reset(dev, drm_minor_alloc_release, minor);
139 if (r)
140 return r;
141
142 minor->kdev = drm_sysfs_minor_alloc(minor);
143 if (IS_ERR(minor->kdev))
144 return PTR_ERR(minor->kdev);
145
146 *drm_minor_get_slot(dev, type) = minor;
147 return 0;
148 }
149
drm_minor_register(struct drm_device * dev,unsigned int type)150 static int drm_minor_register(struct drm_device *dev, unsigned int type)
151 {
152 struct drm_minor *minor;
153 unsigned long flags;
154 int ret;
155
156 DRM_DEBUG("\n");
157
158 minor = *drm_minor_get_slot(dev, type);
159 if (!minor)
160 return 0;
161
162 ret = drm_debugfs_init(minor, minor->index, drm_debugfs_root);
163 if (ret) {
164 DRM_ERROR("DRM: Failed to initialize /sys/kernel/debug/dri.\n");
165 goto err_debugfs;
166 }
167
168 ret = device_add(minor->kdev);
169 if (ret)
170 goto err_debugfs;
171
172 /* replace NULL with @minor so lookups will succeed from now on */
173 spin_lock_irqsave(&drm_minor_lock, flags);
174 idr_replace(&drm_minors_idr, minor, minor->index);
175 spin_unlock_irqrestore(&drm_minor_lock, flags);
176
177 DRM_DEBUG("new minor registered %d\n", minor->index);
178 return 0;
179
180 err_debugfs:
181 drm_debugfs_cleanup(minor);
182 return ret;
183 }
184
drm_minor_unregister(struct drm_device * dev,unsigned int type)185 static void drm_minor_unregister(struct drm_device *dev, unsigned int type)
186 {
187 struct drm_minor *minor;
188 unsigned long flags;
189
190 minor = *drm_minor_get_slot(dev, type);
191 if (!minor || !device_is_registered(minor->kdev))
192 return;
193
194 /* replace @minor with NULL so lookups will fail from now on */
195 spin_lock_irqsave(&drm_minor_lock, flags);
196 idr_replace(&drm_minors_idr, NULL, minor->index);
197 spin_unlock_irqrestore(&drm_minor_lock, flags);
198
199 device_del(minor->kdev);
200 dev_set_drvdata(minor->kdev, NULL); /* safety belt */
201 drm_debugfs_cleanup(minor);
202 }
203
204 /*
205 * Looks up the given minor-ID and returns the respective DRM-minor object. The
206 * refence-count of the underlying device is increased so you must release this
207 * object with drm_minor_release().
208 *
209 * As long as you hold this minor, it is guaranteed that the object and the
210 * minor->dev pointer will stay valid! However, the device may get unplugged and
211 * unregistered while you hold the minor.
212 */
drm_minor_acquire(unsigned int minor_id)213 struct drm_minor *drm_minor_acquire(unsigned int minor_id)
214 {
215 struct drm_minor *minor;
216 unsigned long flags;
217
218 spin_lock_irqsave(&drm_minor_lock, flags);
219 minor = idr_find(&drm_minors_idr, minor_id);
220 if (minor)
221 drm_dev_get(minor->dev);
222 spin_unlock_irqrestore(&drm_minor_lock, flags);
223
224 if (!minor) {
225 return ERR_PTR(-ENODEV);
226 } else if (drm_dev_is_unplugged(minor->dev)) {
227 drm_dev_put(minor->dev);
228 return ERR_PTR(-ENODEV);
229 }
230
231 return minor;
232 }
233
drm_minor_release(struct drm_minor * minor)234 void drm_minor_release(struct drm_minor *minor)
235 {
236 drm_dev_put(minor->dev);
237 }
238
239 /**
240 * DOC: driver instance overview
241 *
242 * A device instance for a drm driver is represented by &struct drm_device. This
243 * is allocated and initialized with devm_drm_dev_alloc(), usually from
244 * bus-specific ->probe() callbacks implemented by the driver. The driver then
245 * needs to initialize all the various subsystems for the drm device like memory
246 * management, vblank handling, modesetting support and initial output
247 * configuration plus obviously initialize all the corresponding hardware bits.
248 * Finally when everything is up and running and ready for userspace the device
249 * instance can be published using drm_dev_register().
250 *
251 * There is also deprecated support for initalizing device instances using
252 * bus-specific helpers and the &drm_driver.load callback. But due to
253 * backwards-compatibility needs the device instance have to be published too
254 * early, which requires unpretty global locking to make safe and is therefore
255 * only support for existing drivers not yet converted to the new scheme.
256 *
257 * When cleaning up a device instance everything needs to be done in reverse:
258 * First unpublish the device instance with drm_dev_unregister(). Then clean up
259 * any other resources allocated at device initialization and drop the driver's
260 * reference to &drm_device using drm_dev_put().
261 *
262 * Note that any allocation or resource which is visible to userspace must be
263 * released only when the final drm_dev_put() is called, and not when the
264 * driver is unbound from the underlying physical struct &device. Best to use
265 * &drm_device managed resources with drmm_add_action(), drmm_kmalloc() and
266 * related functions.
267 *
268 * devres managed resources like devm_kmalloc() can only be used for resources
269 * directly related to the underlying hardware device, and only used in code
270 * paths fully protected by drm_dev_enter() and drm_dev_exit().
271 *
272 * Display driver example
273 * ~~~~~~~~~~~~~~~~~~~~~~
274 *
275 * The following example shows a typical structure of a DRM display driver.
276 * The example focus on the probe() function and the other functions that is
277 * almost always present and serves as a demonstration of devm_drm_dev_alloc().
278 *
279 * .. code-block:: c
280 *
281 * struct driver_device {
282 * struct drm_device drm;
283 * void *userspace_facing;
284 * struct clk *pclk;
285 * };
286 *
287 * static const struct drm_driver driver_drm_driver = {
288 * [...]
289 * };
290 *
291 * static int driver_probe(struct platform_device *pdev)
292 * {
293 * struct driver_device *priv;
294 * struct drm_device *drm;
295 * int ret;
296 *
297 * priv = devm_drm_dev_alloc(&pdev->dev, &driver_drm_driver,
298 * struct driver_device, drm);
299 * if (IS_ERR(priv))
300 * return PTR_ERR(priv);
301 * drm = &priv->drm;
302 *
303 * ret = drmm_mode_config_init(drm);
304 * if (ret)
305 * return ret;
306 *
307 * priv->userspace_facing = drmm_kzalloc(..., GFP_KERNEL);
308 * if (!priv->userspace_facing)
309 * return -ENOMEM;
310 *
311 * priv->pclk = devm_clk_get(dev, "PCLK");
312 * if (IS_ERR(priv->pclk))
313 * return PTR_ERR(priv->pclk);
314 *
315 * // Further setup, display pipeline etc
316 *
317 * platform_set_drvdata(pdev, drm);
318 *
319 * drm_mode_config_reset(drm);
320 *
321 * ret = drm_dev_register(drm);
322 * if (ret)
323 * return ret;
324 *
325 * drm_fbdev_generic_setup(drm, 32);
326 *
327 * return 0;
328 * }
329 *
330 * // This function is called before the devm_ resources are released
331 * static int driver_remove(struct platform_device *pdev)
332 * {
333 * struct drm_device *drm = platform_get_drvdata(pdev);
334 *
335 * drm_dev_unregister(drm);
336 * drm_atomic_helper_shutdown(drm)
337 *
338 * return 0;
339 * }
340 *
341 * // This function is called on kernel restart and shutdown
342 * static void driver_shutdown(struct platform_device *pdev)
343 * {
344 * drm_atomic_helper_shutdown(platform_get_drvdata(pdev));
345 * }
346 *
347 * static int __maybe_unused driver_pm_suspend(struct device *dev)
348 * {
349 * return drm_mode_config_helper_suspend(dev_get_drvdata(dev));
350 * }
351 *
352 * static int __maybe_unused driver_pm_resume(struct device *dev)
353 * {
354 * drm_mode_config_helper_resume(dev_get_drvdata(dev));
355 *
356 * return 0;
357 * }
358 *
359 * static const struct dev_pm_ops driver_pm_ops = {
360 * SET_SYSTEM_SLEEP_PM_OPS(driver_pm_suspend, driver_pm_resume)
361 * };
362 *
363 * static struct platform_driver driver_driver = {
364 * .driver = {
365 * [...]
366 * .pm = &driver_pm_ops,
367 * },
368 * .probe = driver_probe,
369 * .remove = driver_remove,
370 * .shutdown = driver_shutdown,
371 * };
372 * module_platform_driver(driver_driver);
373 *
374 * Drivers that want to support device unplugging (USB, DT overlay unload) should
375 * use drm_dev_unplug() instead of drm_dev_unregister(). The driver must protect
376 * regions that is accessing device resources to prevent use after they're
377 * released. This is done using drm_dev_enter() and drm_dev_exit(). There is one
378 * shortcoming however, drm_dev_unplug() marks the drm_device as unplugged before
379 * drm_atomic_helper_shutdown() is called. This means that if the disable code
380 * paths are protected, they will not run on regular driver module unload,
381 * possibily leaving the hardware enabled.
382 */
383
384 /**
385 * drm_put_dev - Unregister and release a DRM device
386 * @dev: DRM device
387 *
388 * Called at module unload time or when a PCI device is unplugged.
389 *
390 * Cleans up all DRM device, calling drm_lastclose().
391 *
392 * Note: Use of this function is deprecated. It will eventually go away
393 * completely. Please use drm_dev_unregister() and drm_dev_put() explicitly
394 * instead to make sure that the device isn't userspace accessible any more
395 * while teardown is in progress, ensuring that userspace can't access an
396 * inconsistent state.
397 */
drm_put_dev(struct drm_device * dev)398 void drm_put_dev(struct drm_device *dev)
399 {
400 DRM_DEBUG("\n");
401
402 if (!dev) {
403 DRM_ERROR("cleanup called no dev\n");
404 return;
405 }
406
407 drm_dev_unregister(dev);
408 drm_dev_put(dev);
409 }
410 EXPORT_SYMBOL(drm_put_dev);
411
412 /**
413 * drm_dev_enter - Enter device critical section
414 * @dev: DRM device
415 * @idx: Pointer to index that will be passed to the matching drm_dev_exit()
416 *
417 * This function marks and protects the beginning of a section that should not
418 * be entered after the device has been unplugged. The section end is marked
419 * with drm_dev_exit(). Calls to this function can be nested.
420 *
421 * Returns:
422 * True if it is OK to enter the section, false otherwise.
423 */
drm_dev_enter(struct drm_device * dev,int * idx)424 bool drm_dev_enter(struct drm_device *dev, int *idx)
425 {
426 *idx = srcu_read_lock(&drm_unplug_srcu);
427
428 if (dev->unplugged) {
429 srcu_read_unlock(&drm_unplug_srcu, *idx);
430 return false;
431 }
432
433 return true;
434 }
435 EXPORT_SYMBOL(drm_dev_enter);
436
437 /**
438 * drm_dev_exit - Exit device critical section
439 * @idx: index returned from drm_dev_enter()
440 *
441 * This function marks the end of a section that should not be entered after
442 * the device has been unplugged.
443 */
drm_dev_exit(int idx)444 void drm_dev_exit(int idx)
445 {
446 srcu_read_unlock(&drm_unplug_srcu, idx);
447 }
448 EXPORT_SYMBOL(drm_dev_exit);
449
450 /**
451 * drm_dev_unplug - unplug a DRM device
452 * @dev: DRM device
453 *
454 * This unplugs a hotpluggable DRM device, which makes it inaccessible to
455 * userspace operations. Entry-points can use drm_dev_enter() and
456 * drm_dev_exit() to protect device resources in a race free manner. This
457 * essentially unregisters the device like drm_dev_unregister(), but can be
458 * called while there are still open users of @dev.
459 */
drm_dev_unplug(struct drm_device * dev)460 void drm_dev_unplug(struct drm_device *dev)
461 {
462 /*
463 * After synchronizing any critical read section is guaranteed to see
464 * the new value of ->unplugged, and any critical section which might
465 * still have seen the old value of ->unplugged is guaranteed to have
466 * finished.
467 */
468 dev->unplugged = true;
469 synchronize_srcu(&drm_unplug_srcu);
470
471 drm_dev_unregister(dev);
472
473 /* Clear all CPU mappings pointing to this device */
474 unmap_mapping_range(dev->anon_inode->i_mapping, 0, 0, 1);
475 }
476 EXPORT_SYMBOL(drm_dev_unplug);
477
478 /*
479 * DRM internal mount
480 * We want to be able to allocate our own "struct address_space" to control
481 * memory-mappings in VRAM (or stolen RAM, ...). However, core MM does not allow
482 * stand-alone address_space objects, so we need an underlying inode. As there
483 * is no way to allocate an independent inode easily, we need a fake internal
484 * VFS mount-point.
485 *
486 * The drm_fs_inode_new() function allocates a new inode, drm_fs_inode_free()
487 * frees it again. You are allowed to use iget() and iput() to get references to
488 * the inode. But each drm_fs_inode_new() call must be paired with exactly one
489 * drm_fs_inode_free() call (which does not have to be the last iput()).
490 * We use drm_fs_inode_*() to manage our internal VFS mount-point and share it
491 * between multiple inode-users. You could, technically, call
492 * iget() + drm_fs_inode_free() directly after alloc and sometime later do an
493 * iput(), but this way you'd end up with a new vfsmount for each inode.
494 */
495
496 static int drm_fs_cnt;
497 static struct vfsmount *drm_fs_mnt;
498
drm_fs_init_fs_context(struct fs_context * fc)499 static int drm_fs_init_fs_context(struct fs_context *fc)
500 {
501 return init_pseudo(fc, 0x010203ff) ? 0 : -ENOMEM;
502 }
503
504 static struct file_system_type drm_fs_type = {
505 .name = "drm",
506 .owner = THIS_MODULE,
507 .init_fs_context = drm_fs_init_fs_context,
508 .kill_sb = kill_anon_super,
509 };
510
drm_fs_inode_new(void)511 static struct inode *drm_fs_inode_new(void)
512 {
513 struct inode *inode;
514 int r;
515
516 r = simple_pin_fs(&drm_fs_type, &drm_fs_mnt, &drm_fs_cnt);
517 if (r < 0) {
518 DRM_ERROR("Cannot mount pseudo fs: %d\n", r);
519 return ERR_PTR(r);
520 }
521
522 inode = alloc_anon_inode(drm_fs_mnt->mnt_sb);
523 if (IS_ERR(inode))
524 simple_release_fs(&drm_fs_mnt, &drm_fs_cnt);
525
526 return inode;
527 }
528
drm_fs_inode_free(struct inode * inode)529 static void drm_fs_inode_free(struct inode *inode)
530 {
531 if (inode) {
532 iput(inode);
533 simple_release_fs(&drm_fs_mnt, &drm_fs_cnt);
534 }
535 }
536
537 /**
538 * DOC: component helper usage recommendations
539 *
540 * DRM drivers that drive hardware where a logical device consists of a pile of
541 * independent hardware blocks are recommended to use the :ref:`component helper
542 * library<component>`. For consistency and better options for code reuse the
543 * following guidelines apply:
544 *
545 * - The entire device initialization procedure should be run from the
546 * &component_master_ops.master_bind callback, starting with
547 * devm_drm_dev_alloc(), then binding all components with
548 * component_bind_all() and finishing with drm_dev_register().
549 *
550 * - The opaque pointer passed to all components through component_bind_all()
551 * should point at &struct drm_device of the device instance, not some driver
552 * specific private structure.
553 *
554 * - The component helper fills the niche where further standardization of
555 * interfaces is not practical. When there already is, or will be, a
556 * standardized interface like &drm_bridge or &drm_panel, providing its own
557 * functions to find such components at driver load time, like
558 * drm_of_find_panel_or_bridge(), then the component helper should not be
559 * used.
560 */
561
drm_dev_init_release(struct drm_device * dev,void * res)562 static void drm_dev_init_release(struct drm_device *dev, void *res)
563 {
564 drm_legacy_ctxbitmap_cleanup(dev);
565 drm_legacy_remove_map_hash(dev);
566 drm_fs_inode_free(dev->anon_inode);
567
568 put_device(dev->dev);
569 /* Prevent use-after-free in drm_managed_release when debugging is
570 * enabled. Slightly awkward, but can't really be helped. */
571 dev->dev = NULL;
572 mutex_destroy(&dev->master_mutex);
573 mutex_destroy(&dev->clientlist_mutex);
574 mutex_destroy(&dev->filelist_mutex);
575 mutex_destroy(&dev->struct_mutex);
576 drm_legacy_destroy_members(dev);
577 }
578
drm_dev_init(struct drm_device * dev,const struct drm_driver * driver,struct device * parent)579 static int drm_dev_init(struct drm_device *dev,
580 const struct drm_driver *driver,
581 struct device *parent)
582 {
583 int ret;
584
585 if (!drm_core_init_complete) {
586 DRM_ERROR("DRM core is not initialized\n");
587 return -ENODEV;
588 }
589
590 if (WARN_ON(!parent))
591 return -EINVAL;
592
593 kref_init(&dev->ref);
594 dev->dev = get_device(parent);
595 dev->driver = driver;
596
597 INIT_LIST_HEAD(&dev->managed.resources);
598 spin_lock_init(&dev->managed.lock);
599
600 /* no per-device feature limits by default */
601 dev->driver_features = ~0u;
602
603 drm_legacy_init_members(dev);
604 INIT_LIST_HEAD(&dev->filelist);
605 INIT_LIST_HEAD(&dev->filelist_internal);
606 INIT_LIST_HEAD(&dev->clientlist);
607 INIT_LIST_HEAD(&dev->vblank_event_list);
608
609 spin_lock_init(&dev->event_lock);
610 mutex_init(&dev->struct_mutex);
611 mutex_init(&dev->filelist_mutex);
612 mutex_init(&dev->clientlist_mutex);
613 mutex_init(&dev->master_mutex);
614
615 ret = drmm_add_action(dev, drm_dev_init_release, NULL);
616 if (ret)
617 return ret;
618
619 dev->anon_inode = drm_fs_inode_new();
620 if (IS_ERR(dev->anon_inode)) {
621 ret = PTR_ERR(dev->anon_inode);
622 DRM_ERROR("Cannot allocate anonymous inode: %d\n", ret);
623 goto err;
624 }
625
626 if (drm_core_check_feature(dev, DRIVER_RENDER)) {
627 ret = drm_minor_alloc(dev, DRM_MINOR_RENDER);
628 if (ret)
629 goto err;
630 }
631
632 ret = drm_minor_alloc(dev, DRM_MINOR_PRIMARY);
633 if (ret)
634 goto err;
635
636 ret = drm_legacy_create_map_hash(dev);
637 if (ret)
638 goto err;
639
640 drm_legacy_ctxbitmap_init(dev);
641
642 if (drm_core_check_feature(dev, DRIVER_GEM)) {
643 ret = drm_gem_init(dev);
644 if (ret) {
645 DRM_ERROR("Cannot initialize graphics execution manager (GEM)\n");
646 goto err;
647 }
648 }
649
650 ret = drm_dev_set_unique(dev, dev_name(parent));
651 if (ret)
652 goto err;
653
654 return 0;
655
656 err:
657 drm_managed_release(dev);
658
659 return ret;
660 }
661
devm_drm_dev_init_release(void * data)662 static void devm_drm_dev_init_release(void *data)
663 {
664 drm_dev_put(data);
665 }
666
devm_drm_dev_init(struct device * parent,struct drm_device * dev,const struct drm_driver * driver)667 static int devm_drm_dev_init(struct device *parent,
668 struct drm_device *dev,
669 const struct drm_driver *driver)
670 {
671 int ret;
672
673 ret = drm_dev_init(dev, driver, parent);
674 if (ret)
675 return ret;
676
677 return devm_add_action_or_reset(parent,
678 devm_drm_dev_init_release, dev);
679 }
680
__devm_drm_dev_alloc(struct device * parent,const struct drm_driver * driver,size_t size,size_t offset)681 void *__devm_drm_dev_alloc(struct device *parent,
682 const struct drm_driver *driver,
683 size_t size, size_t offset)
684 {
685 void *container;
686 struct drm_device *drm;
687 int ret;
688
689 container = kzalloc(size, GFP_KERNEL);
690 if (!container)
691 return ERR_PTR(-ENOMEM);
692
693 drm = container + offset;
694 ret = devm_drm_dev_init(parent, drm, driver);
695 if (ret) {
696 kfree(container);
697 return ERR_PTR(ret);
698 }
699 drmm_add_final_kfree(drm, container);
700
701 return container;
702 }
703 EXPORT_SYMBOL(__devm_drm_dev_alloc);
704
705 /**
706 * drm_dev_alloc - Allocate new DRM device
707 * @driver: DRM driver to allocate device for
708 * @parent: Parent device object
709 *
710 * This is the deprecated version of devm_drm_dev_alloc(), which does not support
711 * subclassing through embedding the struct &drm_device in a driver private
712 * structure, and which does not support automatic cleanup through devres.
713 *
714 * RETURNS:
715 * Pointer to new DRM device, or ERR_PTR on failure.
716 */
drm_dev_alloc(const struct drm_driver * driver,struct device * parent)717 struct drm_device *drm_dev_alloc(const struct drm_driver *driver,
718 struct device *parent)
719 {
720 struct drm_device *dev;
721 int ret;
722
723 dev = kzalloc(sizeof(*dev), GFP_KERNEL);
724 if (!dev)
725 return ERR_PTR(-ENOMEM);
726
727 ret = drm_dev_init(dev, driver, parent);
728 if (ret) {
729 kfree(dev);
730 return ERR_PTR(ret);
731 }
732
733 drmm_add_final_kfree(dev, dev);
734
735 return dev;
736 }
737 EXPORT_SYMBOL(drm_dev_alloc);
738
drm_dev_release(struct kref * ref)739 static void drm_dev_release(struct kref *ref)
740 {
741 struct drm_device *dev = container_of(ref, struct drm_device, ref);
742
743 if (dev->driver->release)
744 dev->driver->release(dev);
745
746 drm_managed_release(dev);
747
748 kfree(dev->managed.final_kfree);
749 }
750
751 /**
752 * drm_dev_get - Take reference of a DRM device
753 * @dev: device to take reference of or NULL
754 *
755 * This increases the ref-count of @dev by one. You *must* already own a
756 * reference when calling this. Use drm_dev_put() to drop this reference
757 * again.
758 *
759 * This function never fails. However, this function does not provide *any*
760 * guarantee whether the device is alive or running. It only provides a
761 * reference to the object and the memory associated with it.
762 */
drm_dev_get(struct drm_device * dev)763 void drm_dev_get(struct drm_device *dev)
764 {
765 if (dev)
766 kref_get(&dev->ref);
767 }
768 EXPORT_SYMBOL(drm_dev_get);
769
770 /**
771 * drm_dev_put - Drop reference of a DRM device
772 * @dev: device to drop reference of or NULL
773 *
774 * This decreases the ref-count of @dev by one. The device is destroyed if the
775 * ref-count drops to zero.
776 */
drm_dev_put(struct drm_device * dev)777 void drm_dev_put(struct drm_device *dev)
778 {
779 if (dev)
780 kref_put(&dev->ref, drm_dev_release);
781 }
782 EXPORT_SYMBOL(drm_dev_put);
783
create_compat_control_link(struct drm_device * dev)784 static int create_compat_control_link(struct drm_device *dev)
785 {
786 struct drm_minor *minor;
787 char *name;
788 int ret;
789
790 if (!drm_core_check_feature(dev, DRIVER_MODESET))
791 return 0;
792
793 minor = *drm_minor_get_slot(dev, DRM_MINOR_PRIMARY);
794 if (!minor)
795 return 0;
796
797 /*
798 * Some existing userspace out there uses the existing of the controlD*
799 * sysfs files to figure out whether it's a modeset driver. It only does
800 * readdir, hence a symlink is sufficient (and the least confusing
801 * option). Otherwise controlD* is entirely unused.
802 *
803 * Old controlD chardev have been allocated in the range
804 * 64-127.
805 */
806 name = kasprintf(GFP_KERNEL, "controlD%d", minor->index + 64);
807 if (!name)
808 return -ENOMEM;
809
810 ret = sysfs_create_link(minor->kdev->kobj.parent,
811 &minor->kdev->kobj,
812 name);
813
814 kfree(name);
815
816 return ret;
817 }
818
remove_compat_control_link(struct drm_device * dev)819 static void remove_compat_control_link(struct drm_device *dev)
820 {
821 struct drm_minor *minor;
822 char *name;
823
824 if (!drm_core_check_feature(dev, DRIVER_MODESET))
825 return;
826
827 minor = *drm_minor_get_slot(dev, DRM_MINOR_PRIMARY);
828 if (!minor)
829 return;
830
831 name = kasprintf(GFP_KERNEL, "controlD%d", minor->index + 64);
832 if (!name)
833 return;
834
835 sysfs_remove_link(minor->kdev->kobj.parent, name);
836
837 kfree(name);
838 }
839
840 /**
841 * drm_dev_register - Register DRM device
842 * @dev: Device to register
843 * @flags: Flags passed to the driver's .load() function
844 *
845 * Register the DRM device @dev with the system, advertise device to user-space
846 * and start normal device operation. @dev must be initialized via drm_dev_init()
847 * previously.
848 *
849 * Never call this twice on any device!
850 *
851 * NOTE: To ensure backward compatibility with existing drivers method this
852 * function calls the &drm_driver.load method after registering the device
853 * nodes, creating race conditions. Usage of the &drm_driver.load methods is
854 * therefore deprecated, drivers must perform all initialization before calling
855 * drm_dev_register().
856 *
857 * RETURNS:
858 * 0 on success, negative error code on failure.
859 */
drm_dev_register(struct drm_device * dev,unsigned long flags)860 int drm_dev_register(struct drm_device *dev, unsigned long flags)
861 {
862 const struct drm_driver *driver = dev->driver;
863 int ret;
864
865 if (!driver->load)
866 drm_mode_config_validate(dev);
867
868 WARN_ON(!dev->managed.final_kfree);
869
870 if (drm_dev_needs_global_mutex(dev))
871 mutex_lock(&drm_global_mutex);
872
873 ret = drm_minor_register(dev, DRM_MINOR_RENDER);
874 if (ret)
875 goto err_minors;
876
877 ret = drm_minor_register(dev, DRM_MINOR_PRIMARY);
878 if (ret)
879 goto err_minors;
880
881 ret = create_compat_control_link(dev);
882 if (ret)
883 goto err_minors;
884
885 dev->registered = true;
886
887 if (dev->driver->load) {
888 ret = dev->driver->load(dev, flags);
889 if (ret)
890 goto err_minors;
891 }
892
893 if (drm_core_check_feature(dev, DRIVER_MODESET))
894 drm_modeset_register_all(dev);
895
896 DRM_INFO("Initialized %s %d.%d.%d %s for %s on minor %d\n",
897 driver->name, driver->major, driver->minor,
898 driver->patchlevel, driver->date,
899 dev->dev ? dev_name(dev->dev) : "virtual device",
900 dev->primary->index);
901
902 goto out_unlock;
903
904 err_minors:
905 remove_compat_control_link(dev);
906 drm_minor_unregister(dev, DRM_MINOR_PRIMARY);
907 drm_minor_unregister(dev, DRM_MINOR_RENDER);
908 out_unlock:
909 if (drm_dev_needs_global_mutex(dev))
910 mutex_unlock(&drm_global_mutex);
911 return ret;
912 }
913 EXPORT_SYMBOL(drm_dev_register);
914
915 /**
916 * drm_dev_unregister - Unregister DRM device
917 * @dev: Device to unregister
918 *
919 * Unregister the DRM device from the system. This does the reverse of
920 * drm_dev_register() but does not deallocate the device. The caller must call
921 * drm_dev_put() to drop their final reference.
922 *
923 * A special form of unregistering for hotpluggable devices is drm_dev_unplug(),
924 * which can be called while there are still open users of @dev.
925 *
926 * This should be called first in the device teardown code to make sure
927 * userspace can't access the device instance any more.
928 */
drm_dev_unregister(struct drm_device * dev)929 void drm_dev_unregister(struct drm_device *dev)
930 {
931 if (drm_core_check_feature(dev, DRIVER_LEGACY))
932 drm_lastclose(dev);
933
934 dev->registered = false;
935
936 drm_client_dev_unregister(dev);
937
938 if (drm_core_check_feature(dev, DRIVER_MODESET))
939 drm_modeset_unregister_all(dev);
940
941 if (dev->driver->unload)
942 dev->driver->unload(dev);
943
944 if (dev->agp)
945 drm_pci_agp_destroy(dev);
946
947 drm_legacy_rmmaps(dev);
948
949 remove_compat_control_link(dev);
950 drm_minor_unregister(dev, DRM_MINOR_PRIMARY);
951 drm_minor_unregister(dev, DRM_MINOR_RENDER);
952 }
953 EXPORT_SYMBOL(drm_dev_unregister);
954
955 /**
956 * drm_dev_set_unique - Set the unique name of a DRM device
957 * @dev: device of which to set the unique name
958 * @name: unique name
959 *
960 * Sets the unique name of a DRM device using the specified string. This is
961 * already done by drm_dev_init(), drivers should only override the default
962 * unique name for backwards compatibility reasons.
963 *
964 * Return: 0 on success or a negative error code on failure.
965 */
drm_dev_set_unique(struct drm_device * dev,const char * name)966 int drm_dev_set_unique(struct drm_device *dev, const char *name)
967 {
968 drmm_kfree(dev, dev->unique);
969 dev->unique = drmm_kstrdup(dev, name, GFP_KERNEL);
970
971 return dev->unique ? 0 : -ENOMEM;
972 }
973 EXPORT_SYMBOL(drm_dev_set_unique);
974
975 /*
976 * DRM Core
977 * The DRM core module initializes all global DRM objects and makes them
978 * available to drivers. Once setup, drivers can probe their respective
979 * devices.
980 * Currently, core management includes:
981 * - The "DRM-Global" key/value database
982 * - Global ID management for connectors
983 * - DRM major number allocation
984 * - DRM minor management
985 * - DRM sysfs class
986 * - DRM debugfs root
987 *
988 * Furthermore, the DRM core provides dynamic char-dev lookups. For each
989 * interface registered on a DRM device, you can request minor numbers from DRM
990 * core. DRM core takes care of major-number management and char-dev
991 * registration. A stub ->open() callback forwards any open() requests to the
992 * registered minor.
993 */
994
drm_stub_open(struct inode * inode,struct file * filp)995 static int drm_stub_open(struct inode *inode, struct file *filp)
996 {
997 const struct file_operations *new_fops;
998 struct drm_minor *minor;
999 int err;
1000
1001 DRM_DEBUG("\n");
1002
1003 minor = drm_minor_acquire(iminor(inode));
1004 if (IS_ERR(minor))
1005 return PTR_ERR(minor);
1006
1007 new_fops = fops_get(minor->dev->driver->fops);
1008 if (!new_fops) {
1009 err = -ENODEV;
1010 goto out;
1011 }
1012
1013 replace_fops(filp, new_fops);
1014 if (filp->f_op->open)
1015 err = filp->f_op->open(inode, filp);
1016 else
1017 err = 0;
1018
1019 out:
1020 drm_minor_release(minor);
1021
1022 return err;
1023 }
1024
1025 static const struct file_operations drm_stub_fops = {
1026 .owner = THIS_MODULE,
1027 .open = drm_stub_open,
1028 .llseek = noop_llseek,
1029 };
1030
drm_core_exit(void)1031 static void drm_core_exit(void)
1032 {
1033 unregister_chrdev(DRM_MAJOR, "drm");
1034 debugfs_remove(drm_debugfs_root);
1035 drm_sysfs_destroy();
1036 idr_destroy(&drm_minors_idr);
1037 drm_connector_ida_destroy();
1038 }
1039
drm_core_init(void)1040 static int __init drm_core_init(void)
1041 {
1042 int ret;
1043
1044 drm_connector_ida_init();
1045 idr_init(&drm_minors_idr);
1046
1047 ret = drm_sysfs_init();
1048 if (ret < 0) {
1049 DRM_ERROR("Cannot create DRM class: %d\n", ret);
1050 goto error;
1051 }
1052
1053 drm_debugfs_root = debugfs_create_dir("dri", NULL);
1054
1055 ret = register_chrdev(DRM_MAJOR, "drm", &drm_stub_fops);
1056 if (ret < 0)
1057 goto error;
1058
1059 drm_core_init_complete = true;
1060
1061 DRM_DEBUG("Initialized\n");
1062 return 0;
1063
1064 error:
1065 drm_core_exit();
1066 return ret;
1067 }
1068
1069 module_init(drm_core_init);
1070 module_exit(drm_core_exit);
1071