xref: /openbmc/linux/drivers/gpu/drm/drm_drv.c (revision d623f60d)
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/slab.h>
35 #include <linux/srcu.h>
36 
37 #include <drm/drm_drv.h>
38 #include <drm/drmP.h>
39 
40 #include "drm_crtc_internal.h"
41 #include "drm_legacy.h"
42 #include "drm_internal.h"
43 #include "drm_crtc_internal.h"
44 
45 /*
46  * drm_debug: Enable debug output.
47  * Bitmask of DRM_UT_x. See include/drm/drmP.h for details.
48  */
49 unsigned int drm_debug = 0;
50 EXPORT_SYMBOL(drm_debug);
51 
52 MODULE_AUTHOR("Gareth Hughes, Leif Delgass, José Fonseca, Jon Smirl");
53 MODULE_DESCRIPTION("DRM shared core routines");
54 MODULE_LICENSE("GPL and additional rights");
55 MODULE_PARM_DESC(debug, "Enable debug output, where each bit enables a debug category.\n"
56 "\t\tBit 0 (0x01) will enable CORE messages (drm core code)\n"
57 "\t\tBit 1 (0x02) will enable DRIVER messages (drm controller code)\n"
58 "\t\tBit 2 (0x04) will enable KMS messages (modesetting code)\n"
59 "\t\tBit 3 (0x08) will enable PRIME messages (prime code)\n"
60 "\t\tBit 4 (0x10) will enable ATOMIC messages (atomic code)\n"
61 "\t\tBit 5 (0x20) will enable VBL messages (vblank code)\n"
62 "\t\tBit 7 (0x80) will enable LEASE messages (leasing code)");
63 module_param_named(debug, drm_debug, int, 0600);
64 
65 static DEFINE_SPINLOCK(drm_minor_lock);
66 static struct idr drm_minors_idr;
67 
68 /*
69  * If the drm core fails to init for whatever reason,
70  * we should prevent any drivers from registering with it.
71  * It's best to check this at drm_dev_init(), as some drivers
72  * prefer to embed struct drm_device into their own device
73  * structure and call drm_dev_init() themselves.
74  */
75 static bool drm_core_init_complete = false;
76 
77 static struct dentry *drm_debugfs_root;
78 
79 DEFINE_STATIC_SRCU(drm_unplug_srcu);
80 
81 /*
82  * DRM Minors
83  * A DRM device can provide several char-dev interfaces on the DRM-Major. Each
84  * of them is represented by a drm_minor object. Depending on the capabilities
85  * of the device-driver, different interfaces are registered.
86  *
87  * Minors can be accessed via dev->$minor_name. This pointer is either
88  * NULL or a valid drm_minor pointer and stays valid as long as the device is
89  * valid. This means, DRM minors have the same life-time as the underlying
90  * device. However, this doesn't mean that the minor is active. Minors are
91  * registered and unregistered dynamically according to device-state.
92  */
93 
94 static struct drm_minor **drm_minor_get_slot(struct drm_device *dev,
95 					     unsigned int type)
96 {
97 	switch (type) {
98 	case DRM_MINOR_PRIMARY:
99 		return &dev->primary;
100 	case DRM_MINOR_RENDER:
101 		return &dev->render;
102 	default:
103 		BUG();
104 	}
105 }
106 
107 static int drm_minor_alloc(struct drm_device *dev, unsigned int type)
108 {
109 	struct drm_minor *minor;
110 	unsigned long flags;
111 	int r;
112 
113 	minor = kzalloc(sizeof(*minor), GFP_KERNEL);
114 	if (!minor)
115 		return -ENOMEM;
116 
117 	minor->type = type;
118 	minor->dev = dev;
119 
120 	idr_preload(GFP_KERNEL);
121 	spin_lock_irqsave(&drm_minor_lock, flags);
122 	r = idr_alloc(&drm_minors_idr,
123 		      NULL,
124 		      64 * type,
125 		      64 * (type + 1),
126 		      GFP_NOWAIT);
127 	spin_unlock_irqrestore(&drm_minor_lock, flags);
128 	idr_preload_end();
129 
130 	if (r < 0)
131 		goto err_free;
132 
133 	minor->index = r;
134 
135 	minor->kdev = drm_sysfs_minor_alloc(minor);
136 	if (IS_ERR(minor->kdev)) {
137 		r = PTR_ERR(minor->kdev);
138 		goto err_index;
139 	}
140 
141 	*drm_minor_get_slot(dev, type) = minor;
142 	return 0;
143 
144 err_index:
145 	spin_lock_irqsave(&drm_minor_lock, flags);
146 	idr_remove(&drm_minors_idr, minor->index);
147 	spin_unlock_irqrestore(&drm_minor_lock, flags);
148 err_free:
149 	kfree(minor);
150 	return r;
151 }
152 
153 static void drm_minor_free(struct drm_device *dev, unsigned int type)
154 {
155 	struct drm_minor **slot, *minor;
156 	unsigned long flags;
157 
158 	slot = drm_minor_get_slot(dev, type);
159 	minor = *slot;
160 	if (!minor)
161 		return;
162 
163 	put_device(minor->kdev);
164 
165 	spin_lock_irqsave(&drm_minor_lock, flags);
166 	idr_remove(&drm_minors_idr, minor->index);
167 	spin_unlock_irqrestore(&drm_minor_lock, flags);
168 
169 	kfree(minor);
170 	*slot = NULL;
171 }
172 
173 static int drm_minor_register(struct drm_device *dev, unsigned int type)
174 {
175 	struct drm_minor *minor;
176 	unsigned long flags;
177 	int ret;
178 
179 	DRM_DEBUG("\n");
180 
181 	minor = *drm_minor_get_slot(dev, type);
182 	if (!minor)
183 		return 0;
184 
185 	ret = drm_debugfs_init(minor, minor->index, drm_debugfs_root);
186 	if (ret) {
187 		DRM_ERROR("DRM: Failed to initialize /sys/kernel/debug/dri.\n");
188 		goto err_debugfs;
189 	}
190 
191 	ret = device_add(minor->kdev);
192 	if (ret)
193 		goto err_debugfs;
194 
195 	/* replace NULL with @minor so lookups will succeed from now on */
196 	spin_lock_irqsave(&drm_minor_lock, flags);
197 	idr_replace(&drm_minors_idr, minor, minor->index);
198 	spin_unlock_irqrestore(&drm_minor_lock, flags);
199 
200 	DRM_DEBUG("new minor registered %d\n", minor->index);
201 	return 0;
202 
203 err_debugfs:
204 	drm_debugfs_cleanup(minor);
205 	return ret;
206 }
207 
208 static void drm_minor_unregister(struct drm_device *dev, unsigned int type)
209 {
210 	struct drm_minor *minor;
211 	unsigned long flags;
212 
213 	minor = *drm_minor_get_slot(dev, type);
214 	if (!minor || !device_is_registered(minor->kdev))
215 		return;
216 
217 	/* replace @minor with NULL so lookups will fail from now on */
218 	spin_lock_irqsave(&drm_minor_lock, flags);
219 	idr_replace(&drm_minors_idr, NULL, minor->index);
220 	spin_unlock_irqrestore(&drm_minor_lock, flags);
221 
222 	device_del(minor->kdev);
223 	dev_set_drvdata(minor->kdev, NULL); /* safety belt */
224 	drm_debugfs_cleanup(minor);
225 }
226 
227 /*
228  * Looks up the given minor-ID and returns the respective DRM-minor object. The
229  * refence-count of the underlying device is increased so you must release this
230  * object with drm_minor_release().
231  *
232  * As long as you hold this minor, it is guaranteed that the object and the
233  * minor->dev pointer will stay valid! However, the device may get unplugged and
234  * unregistered while you hold the minor.
235  */
236 struct drm_minor *drm_minor_acquire(unsigned int minor_id)
237 {
238 	struct drm_minor *minor;
239 	unsigned long flags;
240 
241 	spin_lock_irqsave(&drm_minor_lock, flags);
242 	minor = idr_find(&drm_minors_idr, minor_id);
243 	if (minor)
244 		drm_dev_get(minor->dev);
245 	spin_unlock_irqrestore(&drm_minor_lock, flags);
246 
247 	if (!minor) {
248 		return ERR_PTR(-ENODEV);
249 	} else if (drm_dev_is_unplugged(minor->dev)) {
250 		drm_dev_put(minor->dev);
251 		return ERR_PTR(-ENODEV);
252 	}
253 
254 	return minor;
255 }
256 
257 void drm_minor_release(struct drm_minor *minor)
258 {
259 	drm_dev_put(minor->dev);
260 }
261 
262 /**
263  * DOC: driver instance overview
264  *
265  * A device instance for a drm driver is represented by &struct drm_device. This
266  * is allocated with drm_dev_alloc(), usually from bus-specific ->probe()
267  * callbacks implemented by the driver. The driver then needs to initialize all
268  * the various subsystems for the drm device like memory management, vblank
269  * handling, modesetting support and intial output configuration plus obviously
270  * initialize all the corresponding hardware bits. An important part of this is
271  * also calling drm_dev_set_unique() to set the userspace-visible unique name of
272  * this device instance. Finally when everything is up and running and ready for
273  * userspace the device instance can be published using drm_dev_register().
274  *
275  * There is also deprecated support for initalizing device instances using
276  * bus-specific helpers and the &drm_driver.load callback. But due to
277  * backwards-compatibility needs the device instance have to be published too
278  * early, which requires unpretty global locking to make safe and is therefore
279  * only support for existing drivers not yet converted to the new scheme.
280  *
281  * When cleaning up a device instance everything needs to be done in reverse:
282  * First unpublish the device instance with drm_dev_unregister(). Then clean up
283  * any other resources allocated at device initialization and drop the driver's
284  * reference to &drm_device using drm_dev_put().
285  *
286  * Note that the lifetime rules for &drm_device instance has still a lot of
287  * historical baggage. Hence use the reference counting provided by
288  * drm_dev_get() and drm_dev_put() only carefully.
289  *
290  * It is recommended that drivers embed &struct drm_device into their own device
291  * structure, which is supported through drm_dev_init().
292  */
293 
294 /**
295  * drm_put_dev - Unregister and release a DRM device
296  * @dev: DRM device
297  *
298  * Called at module unload time or when a PCI device is unplugged.
299  *
300  * Cleans up all DRM device, calling drm_lastclose().
301  *
302  * Note: Use of this function is deprecated. It will eventually go away
303  * completely.  Please use drm_dev_unregister() and drm_dev_put() explicitly
304  * instead to make sure that the device isn't userspace accessible any more
305  * while teardown is in progress, ensuring that userspace can't access an
306  * inconsistent state.
307  */
308 void drm_put_dev(struct drm_device *dev)
309 {
310 	DRM_DEBUG("\n");
311 
312 	if (!dev) {
313 		DRM_ERROR("cleanup called no dev\n");
314 		return;
315 	}
316 
317 	drm_dev_unregister(dev);
318 	drm_dev_put(dev);
319 }
320 EXPORT_SYMBOL(drm_put_dev);
321 
322 /**
323  * drm_dev_enter - Enter device critical section
324  * @dev: DRM device
325  * @idx: Pointer to index that will be passed to the matching drm_dev_exit()
326  *
327  * This function marks and protects the beginning of a section that should not
328  * be entered after the device has been unplugged. The section end is marked
329  * with drm_dev_exit(). Calls to this function can be nested.
330  *
331  * Returns:
332  * True if it is OK to enter the section, false otherwise.
333  */
334 bool drm_dev_enter(struct drm_device *dev, int *idx)
335 {
336 	*idx = srcu_read_lock(&drm_unplug_srcu);
337 
338 	if (dev->unplugged) {
339 		srcu_read_unlock(&drm_unplug_srcu, *idx);
340 		return false;
341 	}
342 
343 	return true;
344 }
345 EXPORT_SYMBOL(drm_dev_enter);
346 
347 /**
348  * drm_dev_exit - Exit device critical section
349  * @idx: index returned from drm_dev_enter()
350  *
351  * This function marks the end of a section that should not be entered after
352  * the device has been unplugged.
353  */
354 void drm_dev_exit(int idx)
355 {
356 	srcu_read_unlock(&drm_unplug_srcu, idx);
357 }
358 EXPORT_SYMBOL(drm_dev_exit);
359 
360 /**
361  * drm_dev_unplug - unplug a DRM device
362  * @dev: DRM device
363  *
364  * This unplugs a hotpluggable DRM device, which makes it inaccessible to
365  * userspace operations. Entry-points can use drm_dev_enter() and
366  * drm_dev_exit() to protect device resources in a race free manner. This
367  * essentially unregisters the device like drm_dev_unregister(), but can be
368  * called while there are still open users of @dev.
369  */
370 void drm_dev_unplug(struct drm_device *dev)
371 {
372 	/*
373 	 * After synchronizing any critical read section is guaranteed to see
374 	 * the new value of ->unplugged, and any critical section which might
375 	 * still have seen the old value of ->unplugged is guaranteed to have
376 	 * finished.
377 	 */
378 	dev->unplugged = true;
379 	synchronize_srcu(&drm_unplug_srcu);
380 
381 	drm_dev_unregister(dev);
382 
383 	mutex_lock(&drm_global_mutex);
384 	if (dev->open_count == 0)
385 		drm_dev_put(dev);
386 	mutex_unlock(&drm_global_mutex);
387 }
388 EXPORT_SYMBOL(drm_dev_unplug);
389 
390 /*
391  * DRM internal mount
392  * We want to be able to allocate our own "struct address_space" to control
393  * memory-mappings in VRAM (or stolen RAM, ...). However, core MM does not allow
394  * stand-alone address_space objects, so we need an underlying inode. As there
395  * is no way to allocate an independent inode easily, we need a fake internal
396  * VFS mount-point.
397  *
398  * The drm_fs_inode_new() function allocates a new inode, drm_fs_inode_free()
399  * frees it again. You are allowed to use iget() and iput() to get references to
400  * the inode. But each drm_fs_inode_new() call must be paired with exactly one
401  * drm_fs_inode_free() call (which does not have to be the last iput()).
402  * We use drm_fs_inode_*() to manage our internal VFS mount-point and share it
403  * between multiple inode-users. You could, technically, call
404  * iget() + drm_fs_inode_free() directly after alloc and sometime later do an
405  * iput(), but this way you'd end up with a new vfsmount for each inode.
406  */
407 
408 static int drm_fs_cnt;
409 static struct vfsmount *drm_fs_mnt;
410 
411 static const struct dentry_operations drm_fs_dops = {
412 	.d_dname	= simple_dname,
413 };
414 
415 static const struct super_operations drm_fs_sops = {
416 	.statfs		= simple_statfs,
417 };
418 
419 static struct dentry *drm_fs_mount(struct file_system_type *fs_type, int flags,
420 				   const char *dev_name, void *data)
421 {
422 	return mount_pseudo(fs_type,
423 			    "drm:",
424 			    &drm_fs_sops,
425 			    &drm_fs_dops,
426 			    0x010203ff);
427 }
428 
429 static struct file_system_type drm_fs_type = {
430 	.name		= "drm",
431 	.owner		= THIS_MODULE,
432 	.mount		= drm_fs_mount,
433 	.kill_sb	= kill_anon_super,
434 };
435 
436 static struct inode *drm_fs_inode_new(void)
437 {
438 	struct inode *inode;
439 	int r;
440 
441 	r = simple_pin_fs(&drm_fs_type, &drm_fs_mnt, &drm_fs_cnt);
442 	if (r < 0) {
443 		DRM_ERROR("Cannot mount pseudo fs: %d\n", r);
444 		return ERR_PTR(r);
445 	}
446 
447 	inode = alloc_anon_inode(drm_fs_mnt->mnt_sb);
448 	if (IS_ERR(inode))
449 		simple_release_fs(&drm_fs_mnt, &drm_fs_cnt);
450 
451 	return inode;
452 }
453 
454 static void drm_fs_inode_free(struct inode *inode)
455 {
456 	if (inode) {
457 		iput(inode);
458 		simple_release_fs(&drm_fs_mnt, &drm_fs_cnt);
459 	}
460 }
461 
462 /**
463  * drm_dev_init - Initialise new DRM device
464  * @dev: DRM device
465  * @driver: DRM driver
466  * @parent: Parent device object
467  *
468  * Initialize a new DRM device. No device registration is done.
469  * Call drm_dev_register() to advertice the device to user space and register it
470  * with other core subsystems. This should be done last in the device
471  * initialization sequence to make sure userspace can't access an inconsistent
472  * state.
473  *
474  * The initial ref-count of the object is 1. Use drm_dev_get() and
475  * drm_dev_put() to take and drop further ref-counts.
476  *
477  * Note that for purely virtual devices @parent can be NULL.
478  *
479  * Drivers that do not want to allocate their own device struct
480  * embedding &struct drm_device can call drm_dev_alloc() instead. For drivers
481  * that do embed &struct drm_device it must be placed first in the overall
482  * structure, and the overall structure must be allocated using kmalloc(): The
483  * drm core's release function unconditionally calls kfree() on the @dev pointer
484  * when the final reference is released. To override this behaviour, and so
485  * allow embedding of the drm_device inside the driver's device struct at an
486  * arbitrary offset, you must supply a &drm_driver.release callback and control
487  * the finalization explicitly.
488  *
489  * RETURNS:
490  * 0 on success, or error code on failure.
491  */
492 int drm_dev_init(struct drm_device *dev,
493 		 struct drm_driver *driver,
494 		 struct device *parent)
495 {
496 	int ret;
497 
498 	if (!drm_core_init_complete) {
499 		DRM_ERROR("DRM core is not initialized\n");
500 		return -ENODEV;
501 	}
502 
503 	kref_init(&dev->ref);
504 	dev->dev = parent;
505 	dev->driver = driver;
506 
507 	INIT_LIST_HEAD(&dev->filelist);
508 	INIT_LIST_HEAD(&dev->ctxlist);
509 	INIT_LIST_HEAD(&dev->vmalist);
510 	INIT_LIST_HEAD(&dev->maplist);
511 	INIT_LIST_HEAD(&dev->vblank_event_list);
512 
513 	spin_lock_init(&dev->buf_lock);
514 	spin_lock_init(&dev->event_lock);
515 	mutex_init(&dev->struct_mutex);
516 	mutex_init(&dev->filelist_mutex);
517 	mutex_init(&dev->ctxlist_mutex);
518 	mutex_init(&dev->master_mutex);
519 
520 	dev->anon_inode = drm_fs_inode_new();
521 	if (IS_ERR(dev->anon_inode)) {
522 		ret = PTR_ERR(dev->anon_inode);
523 		DRM_ERROR("Cannot allocate anonymous inode: %d\n", ret);
524 		goto err_free;
525 	}
526 
527 	if (drm_core_check_feature(dev, DRIVER_RENDER)) {
528 		ret = drm_minor_alloc(dev, DRM_MINOR_RENDER);
529 		if (ret)
530 			goto err_minors;
531 	}
532 
533 	ret = drm_minor_alloc(dev, DRM_MINOR_PRIMARY);
534 	if (ret)
535 		goto err_minors;
536 
537 	ret = drm_ht_create(&dev->map_hash, 12);
538 	if (ret)
539 		goto err_minors;
540 
541 	drm_legacy_ctxbitmap_init(dev);
542 
543 	if (drm_core_check_feature(dev, DRIVER_GEM)) {
544 		ret = drm_gem_init(dev);
545 		if (ret) {
546 			DRM_ERROR("Cannot initialize graphics execution manager (GEM)\n");
547 			goto err_ctxbitmap;
548 		}
549 	}
550 
551 	/* Use the parent device name as DRM device unique identifier, but fall
552 	 * back to the driver name for virtual devices like vgem. */
553 	ret = drm_dev_set_unique(dev, parent ? dev_name(parent) : driver->name);
554 	if (ret)
555 		goto err_setunique;
556 
557 	return 0;
558 
559 err_setunique:
560 	if (drm_core_check_feature(dev, DRIVER_GEM))
561 		drm_gem_destroy(dev);
562 err_ctxbitmap:
563 	drm_legacy_ctxbitmap_cleanup(dev);
564 	drm_ht_remove(&dev->map_hash);
565 err_minors:
566 	drm_minor_free(dev, DRM_MINOR_PRIMARY);
567 	drm_minor_free(dev, DRM_MINOR_RENDER);
568 	drm_fs_inode_free(dev->anon_inode);
569 err_free:
570 	mutex_destroy(&dev->master_mutex);
571 	mutex_destroy(&dev->ctxlist_mutex);
572 	mutex_destroy(&dev->filelist_mutex);
573 	mutex_destroy(&dev->struct_mutex);
574 	return ret;
575 }
576 EXPORT_SYMBOL(drm_dev_init);
577 
578 /**
579  * drm_dev_fini - Finalize a dead DRM device
580  * @dev: DRM device
581  *
582  * Finalize a dead DRM device. This is the converse to drm_dev_init() and
583  * frees up all data allocated by it. All driver private data should be
584  * finalized first. Note that this function does not free the @dev, that is
585  * left to the caller.
586  *
587  * The ref-count of @dev must be zero, and drm_dev_fini() should only be called
588  * from a &drm_driver.release callback.
589  */
590 void drm_dev_fini(struct drm_device *dev)
591 {
592 	drm_vblank_cleanup(dev);
593 
594 	if (drm_core_check_feature(dev, DRIVER_GEM))
595 		drm_gem_destroy(dev);
596 
597 	drm_legacy_ctxbitmap_cleanup(dev);
598 	drm_ht_remove(&dev->map_hash);
599 	drm_fs_inode_free(dev->anon_inode);
600 
601 	drm_minor_free(dev, DRM_MINOR_PRIMARY);
602 	drm_minor_free(dev, DRM_MINOR_RENDER);
603 
604 	mutex_destroy(&dev->master_mutex);
605 	mutex_destroy(&dev->ctxlist_mutex);
606 	mutex_destroy(&dev->filelist_mutex);
607 	mutex_destroy(&dev->struct_mutex);
608 	kfree(dev->unique);
609 }
610 EXPORT_SYMBOL(drm_dev_fini);
611 
612 /**
613  * drm_dev_alloc - Allocate new DRM device
614  * @driver: DRM driver to allocate device for
615  * @parent: Parent device object
616  *
617  * Allocate and initialize a new DRM device. No device registration is done.
618  * Call drm_dev_register() to advertice the device to user space and register it
619  * with other core subsystems. This should be done last in the device
620  * initialization sequence to make sure userspace can't access an inconsistent
621  * state.
622  *
623  * The initial ref-count of the object is 1. Use drm_dev_get() and
624  * drm_dev_put() to take and drop further ref-counts.
625  *
626  * Note that for purely virtual devices @parent can be NULL.
627  *
628  * Drivers that wish to subclass or embed &struct drm_device into their
629  * own struct should look at using drm_dev_init() instead.
630  *
631  * RETURNS:
632  * Pointer to new DRM device, or ERR_PTR on failure.
633  */
634 struct drm_device *drm_dev_alloc(struct drm_driver *driver,
635 				 struct device *parent)
636 {
637 	struct drm_device *dev;
638 	int ret;
639 
640 	dev = kzalloc(sizeof(*dev), GFP_KERNEL);
641 	if (!dev)
642 		return ERR_PTR(-ENOMEM);
643 
644 	ret = drm_dev_init(dev, driver, parent);
645 	if (ret) {
646 		kfree(dev);
647 		return ERR_PTR(ret);
648 	}
649 
650 	return dev;
651 }
652 EXPORT_SYMBOL(drm_dev_alloc);
653 
654 static void drm_dev_release(struct kref *ref)
655 {
656 	struct drm_device *dev = container_of(ref, struct drm_device, ref);
657 
658 	if (dev->driver->release) {
659 		dev->driver->release(dev);
660 	} else {
661 		drm_dev_fini(dev);
662 		kfree(dev);
663 	}
664 }
665 
666 /**
667  * drm_dev_get - Take reference of a DRM device
668  * @dev: device to take reference of or NULL
669  *
670  * This increases the ref-count of @dev by one. You *must* already own a
671  * reference when calling this. Use drm_dev_put() to drop this reference
672  * again.
673  *
674  * This function never fails. However, this function does not provide *any*
675  * guarantee whether the device is alive or running. It only provides a
676  * reference to the object and the memory associated with it.
677  */
678 void drm_dev_get(struct drm_device *dev)
679 {
680 	if (dev)
681 		kref_get(&dev->ref);
682 }
683 EXPORT_SYMBOL(drm_dev_get);
684 
685 /**
686  * drm_dev_put - Drop reference of a DRM device
687  * @dev: device to drop reference of or NULL
688  *
689  * This decreases the ref-count of @dev by one. The device is destroyed if the
690  * ref-count drops to zero.
691  */
692 void drm_dev_put(struct drm_device *dev)
693 {
694 	if (dev)
695 		kref_put(&dev->ref, drm_dev_release);
696 }
697 EXPORT_SYMBOL(drm_dev_put);
698 
699 /**
700  * drm_dev_unref - Drop reference of a DRM device
701  * @dev: device to drop reference of or NULL
702  *
703  * This is a compatibility alias for drm_dev_put() and should not be used by new
704  * code.
705  */
706 void drm_dev_unref(struct drm_device *dev)
707 {
708 	drm_dev_put(dev);
709 }
710 EXPORT_SYMBOL(drm_dev_unref);
711 
712 static int create_compat_control_link(struct drm_device *dev)
713 {
714 	struct drm_minor *minor;
715 	char *name;
716 	int ret;
717 
718 	if (!drm_core_check_feature(dev, DRIVER_MODESET))
719 		return 0;
720 
721 	minor = *drm_minor_get_slot(dev, DRM_MINOR_PRIMARY);
722 	if (!minor)
723 		return 0;
724 
725 	/*
726 	 * Some existing userspace out there uses the existing of the controlD*
727 	 * sysfs files to figure out whether it's a modeset driver. It only does
728 	 * readdir, hence a symlink is sufficient (and the least confusing
729 	 * option). Otherwise controlD* is entirely unused.
730 	 *
731 	 * Old controlD chardev have been allocated in the range
732 	 * 64-127.
733 	 */
734 	name = kasprintf(GFP_KERNEL, "controlD%d", minor->index + 64);
735 	if (!name)
736 		return -ENOMEM;
737 
738 	ret = sysfs_create_link(minor->kdev->kobj.parent,
739 				&minor->kdev->kobj,
740 				name);
741 
742 	kfree(name);
743 
744 	return ret;
745 }
746 
747 static void remove_compat_control_link(struct drm_device *dev)
748 {
749 	struct drm_minor *minor;
750 	char *name;
751 
752 	if (!drm_core_check_feature(dev, DRIVER_MODESET))
753 		return;
754 
755 	minor = *drm_minor_get_slot(dev, DRM_MINOR_PRIMARY);
756 	if (!minor)
757 		return;
758 
759 	name = kasprintf(GFP_KERNEL, "controlD%d", minor->index + 64);
760 	if (!name)
761 		return;
762 
763 	sysfs_remove_link(minor->kdev->kobj.parent, name);
764 
765 	kfree(name);
766 }
767 
768 /**
769  * drm_dev_register - Register DRM device
770  * @dev: Device to register
771  * @flags: Flags passed to the driver's .load() function
772  *
773  * Register the DRM device @dev with the system, advertise device to user-space
774  * and start normal device operation. @dev must be allocated via drm_dev_alloc()
775  * previously.
776  *
777  * Never call this twice on any device!
778  *
779  * NOTE: To ensure backward compatibility with existing drivers method this
780  * function calls the &drm_driver.load method after registering the device
781  * nodes, creating race conditions. Usage of the &drm_driver.load methods is
782  * therefore deprecated, drivers must perform all initialization before calling
783  * drm_dev_register().
784  *
785  * RETURNS:
786  * 0 on success, negative error code on failure.
787  */
788 int drm_dev_register(struct drm_device *dev, unsigned long flags)
789 {
790 	struct drm_driver *driver = dev->driver;
791 	int ret;
792 
793 	mutex_lock(&drm_global_mutex);
794 
795 	ret = drm_minor_register(dev, DRM_MINOR_RENDER);
796 	if (ret)
797 		goto err_minors;
798 
799 	ret = drm_minor_register(dev, DRM_MINOR_PRIMARY);
800 	if (ret)
801 		goto err_minors;
802 
803 	ret = create_compat_control_link(dev);
804 	if (ret)
805 		goto err_minors;
806 
807 	dev->registered = true;
808 
809 	if (dev->driver->load) {
810 		ret = dev->driver->load(dev, flags);
811 		if (ret)
812 			goto err_minors;
813 	}
814 
815 	if (drm_core_check_feature(dev, DRIVER_MODESET))
816 		drm_modeset_register_all(dev);
817 
818 	ret = 0;
819 
820 	DRM_INFO("Initialized %s %d.%d.%d %s for %s on minor %d\n",
821 		 driver->name, driver->major, driver->minor,
822 		 driver->patchlevel, driver->date,
823 		 dev->dev ? dev_name(dev->dev) : "virtual device",
824 		 dev->primary->index);
825 
826 	goto out_unlock;
827 
828 err_minors:
829 	remove_compat_control_link(dev);
830 	drm_minor_unregister(dev, DRM_MINOR_PRIMARY);
831 	drm_minor_unregister(dev, DRM_MINOR_RENDER);
832 out_unlock:
833 	mutex_unlock(&drm_global_mutex);
834 	return ret;
835 }
836 EXPORT_SYMBOL(drm_dev_register);
837 
838 /**
839  * drm_dev_unregister - Unregister DRM device
840  * @dev: Device to unregister
841  *
842  * Unregister the DRM device from the system. This does the reverse of
843  * drm_dev_register() but does not deallocate the device. The caller must call
844  * drm_dev_put() to drop their final reference.
845  *
846  * A special form of unregistering for hotpluggable devices is drm_dev_unplug(),
847  * which can be called while there are still open users of @dev.
848  *
849  * This should be called first in the device teardown code to make sure
850  * userspace can't access the device instance any more.
851  */
852 void drm_dev_unregister(struct drm_device *dev)
853 {
854 	struct drm_map_list *r_list, *list_temp;
855 
856 	if (drm_core_check_feature(dev, DRIVER_LEGACY))
857 		drm_lastclose(dev);
858 
859 	dev->registered = false;
860 
861 	if (drm_core_check_feature(dev, DRIVER_MODESET))
862 		drm_modeset_unregister_all(dev);
863 
864 	if (dev->driver->unload)
865 		dev->driver->unload(dev);
866 
867 	if (dev->agp)
868 		drm_pci_agp_destroy(dev);
869 
870 	list_for_each_entry_safe(r_list, list_temp, &dev->maplist, head)
871 		drm_legacy_rmmap(dev, r_list->map);
872 
873 	remove_compat_control_link(dev);
874 	drm_minor_unregister(dev, DRM_MINOR_PRIMARY);
875 	drm_minor_unregister(dev, DRM_MINOR_RENDER);
876 }
877 EXPORT_SYMBOL(drm_dev_unregister);
878 
879 /**
880  * drm_dev_set_unique - Set the unique name of a DRM device
881  * @dev: device of which to set the unique name
882  * @name: unique name
883  *
884  * Sets the unique name of a DRM device using the specified string. Drivers
885  * can use this at driver probe time if the unique name of the devices they
886  * drive is static.
887  *
888  * Return: 0 on success or a negative error code on failure.
889  */
890 int drm_dev_set_unique(struct drm_device *dev, const char *name)
891 {
892 	kfree(dev->unique);
893 	dev->unique = kstrdup(name, GFP_KERNEL);
894 
895 	return dev->unique ? 0 : -ENOMEM;
896 }
897 EXPORT_SYMBOL(drm_dev_set_unique);
898 
899 /*
900  * DRM Core
901  * The DRM core module initializes all global DRM objects and makes them
902  * available to drivers. Once setup, drivers can probe their respective
903  * devices.
904  * Currently, core management includes:
905  *  - The "DRM-Global" key/value database
906  *  - Global ID management for connectors
907  *  - DRM major number allocation
908  *  - DRM minor management
909  *  - DRM sysfs class
910  *  - DRM debugfs root
911  *
912  * Furthermore, the DRM core provides dynamic char-dev lookups. For each
913  * interface registered on a DRM device, you can request minor numbers from DRM
914  * core. DRM core takes care of major-number management and char-dev
915  * registration. A stub ->open() callback forwards any open() requests to the
916  * registered minor.
917  */
918 
919 static int drm_stub_open(struct inode *inode, struct file *filp)
920 {
921 	const struct file_operations *new_fops;
922 	struct drm_minor *minor;
923 	int err;
924 
925 	DRM_DEBUG("\n");
926 
927 	mutex_lock(&drm_global_mutex);
928 	minor = drm_minor_acquire(iminor(inode));
929 	if (IS_ERR(minor)) {
930 		err = PTR_ERR(minor);
931 		goto out_unlock;
932 	}
933 
934 	new_fops = fops_get(minor->dev->driver->fops);
935 	if (!new_fops) {
936 		err = -ENODEV;
937 		goto out_release;
938 	}
939 
940 	replace_fops(filp, new_fops);
941 	if (filp->f_op->open)
942 		err = filp->f_op->open(inode, filp);
943 	else
944 		err = 0;
945 
946 out_release:
947 	drm_minor_release(minor);
948 out_unlock:
949 	mutex_unlock(&drm_global_mutex);
950 	return err;
951 }
952 
953 static const struct file_operations drm_stub_fops = {
954 	.owner = THIS_MODULE,
955 	.open = drm_stub_open,
956 	.llseek = noop_llseek,
957 };
958 
959 static void drm_core_exit(void)
960 {
961 	unregister_chrdev(DRM_MAJOR, "drm");
962 	debugfs_remove(drm_debugfs_root);
963 	drm_sysfs_destroy();
964 	idr_destroy(&drm_minors_idr);
965 	drm_connector_ida_destroy();
966 	drm_global_release();
967 }
968 
969 static int __init drm_core_init(void)
970 {
971 	int ret;
972 
973 	drm_global_init();
974 	drm_connector_ida_init();
975 	idr_init(&drm_minors_idr);
976 
977 	ret = drm_sysfs_init();
978 	if (ret < 0) {
979 		DRM_ERROR("Cannot create DRM class: %d\n", ret);
980 		goto error;
981 	}
982 
983 	drm_debugfs_root = debugfs_create_dir("dri", NULL);
984 	if (!drm_debugfs_root) {
985 		ret = -ENOMEM;
986 		DRM_ERROR("Cannot create debugfs-root: %d\n", ret);
987 		goto error;
988 	}
989 
990 	ret = register_chrdev(DRM_MAJOR, "drm", &drm_stub_fops);
991 	if (ret < 0)
992 		goto error;
993 
994 	drm_core_init_complete = true;
995 
996 	DRM_DEBUG("Initialized\n");
997 	return 0;
998 
999 error:
1000 	drm_core_exit();
1001 	return ret;
1002 }
1003 
1004 module_init(drm_core_init);
1005 module_exit(drm_core_exit);
1006