xref: /openbmc/linux/drivers/gpu/drm/drm_drv.c (revision b8d312aa)
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_mode_object.h>
43 #include <drm/drm_print.h>
44 
45 #include "drm_crtc_internal.h"
46 #include "drm_internal.h"
47 #include "drm_legacy.h"
48 
49 /*
50  * drm_debug: Enable debug output.
51  * Bitmask of DRM_UT_x. See include/drm/drm_print.h for details.
52  */
53 unsigned int drm_debug = 0;
54 EXPORT_SYMBOL(drm_debug);
55 
56 MODULE_AUTHOR("Gareth Hughes, Leif Delgass, José Fonseca, Jon Smirl");
57 MODULE_DESCRIPTION("DRM shared core routines");
58 MODULE_LICENSE("GPL and additional rights");
59 MODULE_PARM_DESC(debug, "Enable debug output, where each bit enables a debug category.\n"
60 "\t\tBit 0 (0x01)  will enable CORE messages (drm core code)\n"
61 "\t\tBit 1 (0x02)  will enable DRIVER messages (drm controller code)\n"
62 "\t\tBit 2 (0x04)  will enable KMS messages (modesetting code)\n"
63 "\t\tBit 3 (0x08)  will enable PRIME messages (prime code)\n"
64 "\t\tBit 4 (0x10)  will enable ATOMIC messages (atomic code)\n"
65 "\t\tBit 5 (0x20)  will enable VBL messages (vblank code)\n"
66 "\t\tBit 7 (0x80)  will enable LEASE messages (leasing code)\n"
67 "\t\tBit 8 (0x100) will enable DP messages (displayport code)");
68 module_param_named(debug, drm_debug, int, 0600);
69 
70 static DEFINE_SPINLOCK(drm_minor_lock);
71 static struct idr drm_minors_idr;
72 
73 /*
74  * If the drm core fails to init for whatever reason,
75  * we should prevent any drivers from registering with it.
76  * It's best to check this at drm_dev_init(), as some drivers
77  * prefer to embed struct drm_device into their own device
78  * structure and call drm_dev_init() themselves.
79  */
80 static bool drm_core_init_complete = false;
81 
82 static struct dentry *drm_debugfs_root;
83 
84 DEFINE_STATIC_SRCU(drm_unplug_srcu);
85 
86 /*
87  * DRM Minors
88  * A DRM device can provide several char-dev interfaces on the DRM-Major. Each
89  * of them is represented by a drm_minor object. Depending on the capabilities
90  * of the device-driver, different interfaces are registered.
91  *
92  * Minors can be accessed via dev->$minor_name. This pointer is either
93  * NULL or a valid drm_minor pointer and stays valid as long as the device is
94  * valid. This means, DRM minors have the same life-time as the underlying
95  * device. However, this doesn't mean that the minor is active. Minors are
96  * registered and unregistered dynamically according to device-state.
97  */
98 
99 static struct drm_minor **drm_minor_get_slot(struct drm_device *dev,
100 					     unsigned int type)
101 {
102 	switch (type) {
103 	case DRM_MINOR_PRIMARY:
104 		return &dev->primary;
105 	case DRM_MINOR_RENDER:
106 		return &dev->render;
107 	default:
108 		BUG();
109 	}
110 }
111 
112 static int drm_minor_alloc(struct drm_device *dev, unsigned int type)
113 {
114 	struct drm_minor *minor;
115 	unsigned long flags;
116 	int r;
117 
118 	minor = kzalloc(sizeof(*minor), GFP_KERNEL);
119 	if (!minor)
120 		return -ENOMEM;
121 
122 	minor->type = type;
123 	minor->dev = dev;
124 
125 	idr_preload(GFP_KERNEL);
126 	spin_lock_irqsave(&drm_minor_lock, flags);
127 	r = idr_alloc(&drm_minors_idr,
128 		      NULL,
129 		      64 * type,
130 		      64 * (type + 1),
131 		      GFP_NOWAIT);
132 	spin_unlock_irqrestore(&drm_minor_lock, flags);
133 	idr_preload_end();
134 
135 	if (r < 0)
136 		goto err_free;
137 
138 	minor->index = r;
139 
140 	minor->kdev = drm_sysfs_minor_alloc(minor);
141 	if (IS_ERR(minor->kdev)) {
142 		r = PTR_ERR(minor->kdev);
143 		goto err_index;
144 	}
145 
146 	*drm_minor_get_slot(dev, type) = minor;
147 	return 0;
148 
149 err_index:
150 	spin_lock_irqsave(&drm_minor_lock, flags);
151 	idr_remove(&drm_minors_idr, minor->index);
152 	spin_unlock_irqrestore(&drm_minor_lock, flags);
153 err_free:
154 	kfree(minor);
155 	return r;
156 }
157 
158 static void drm_minor_free(struct drm_device *dev, unsigned int type)
159 {
160 	struct drm_minor **slot, *minor;
161 	unsigned long flags;
162 
163 	slot = drm_minor_get_slot(dev, type);
164 	minor = *slot;
165 	if (!minor)
166 		return;
167 
168 	put_device(minor->kdev);
169 
170 	spin_lock_irqsave(&drm_minor_lock, flags);
171 	idr_remove(&drm_minors_idr, minor->index);
172 	spin_unlock_irqrestore(&drm_minor_lock, flags);
173 
174 	kfree(minor);
175 	*slot = NULL;
176 }
177 
178 static int drm_minor_register(struct drm_device *dev, unsigned int type)
179 {
180 	struct drm_minor *minor;
181 	unsigned long flags;
182 	int ret;
183 
184 	DRM_DEBUG("\n");
185 
186 	minor = *drm_minor_get_slot(dev, type);
187 	if (!minor)
188 		return 0;
189 
190 	ret = drm_debugfs_init(minor, minor->index, drm_debugfs_root);
191 	if (ret) {
192 		DRM_ERROR("DRM: Failed to initialize /sys/kernel/debug/dri.\n");
193 		goto err_debugfs;
194 	}
195 
196 	ret = device_add(minor->kdev);
197 	if (ret)
198 		goto err_debugfs;
199 
200 	/* replace NULL with @minor so lookups will succeed from now on */
201 	spin_lock_irqsave(&drm_minor_lock, flags);
202 	idr_replace(&drm_minors_idr, minor, minor->index);
203 	spin_unlock_irqrestore(&drm_minor_lock, flags);
204 
205 	DRM_DEBUG("new minor registered %d\n", minor->index);
206 	return 0;
207 
208 err_debugfs:
209 	drm_debugfs_cleanup(minor);
210 	return ret;
211 }
212 
213 static void drm_minor_unregister(struct drm_device *dev, unsigned int type)
214 {
215 	struct drm_minor *minor;
216 	unsigned long flags;
217 
218 	minor = *drm_minor_get_slot(dev, type);
219 	if (!minor || !device_is_registered(minor->kdev))
220 		return;
221 
222 	/* replace @minor with NULL so lookups will fail from now on */
223 	spin_lock_irqsave(&drm_minor_lock, flags);
224 	idr_replace(&drm_minors_idr, NULL, minor->index);
225 	spin_unlock_irqrestore(&drm_minor_lock, flags);
226 
227 	device_del(minor->kdev);
228 	dev_set_drvdata(minor->kdev, NULL); /* safety belt */
229 	drm_debugfs_cleanup(minor);
230 }
231 
232 /*
233  * Looks up the given minor-ID and returns the respective DRM-minor object. The
234  * refence-count of the underlying device is increased so you must release this
235  * object with drm_minor_release().
236  *
237  * As long as you hold this minor, it is guaranteed that the object and the
238  * minor->dev pointer will stay valid! However, the device may get unplugged and
239  * unregistered while you hold the minor.
240  */
241 struct drm_minor *drm_minor_acquire(unsigned int minor_id)
242 {
243 	struct drm_minor *minor;
244 	unsigned long flags;
245 
246 	spin_lock_irqsave(&drm_minor_lock, flags);
247 	minor = idr_find(&drm_minors_idr, minor_id);
248 	if (minor)
249 		drm_dev_get(minor->dev);
250 	spin_unlock_irqrestore(&drm_minor_lock, flags);
251 
252 	if (!minor) {
253 		return ERR_PTR(-ENODEV);
254 	} else if (drm_dev_is_unplugged(minor->dev)) {
255 		drm_dev_put(minor->dev);
256 		return ERR_PTR(-ENODEV);
257 	}
258 
259 	return minor;
260 }
261 
262 void drm_minor_release(struct drm_minor *minor)
263 {
264 	drm_dev_put(minor->dev);
265 }
266 
267 /**
268  * DOC: driver instance overview
269  *
270  * A device instance for a drm driver is represented by &struct drm_device. This
271  * is initialized with drm_dev_init(), usually from bus-specific ->probe()
272  * callbacks implemented by the driver. The driver then needs to initialize all
273  * the various subsystems for the drm device like memory management, vblank
274  * handling, modesetting support and intial output configuration plus obviously
275  * initialize all the corresponding hardware bits. Finally when everything is up
276  * and running and ready for userspace the device instance can be published
277  * using drm_dev_register().
278  *
279  * There is also deprecated support for initalizing device instances using
280  * bus-specific helpers and the &drm_driver.load callback. But due to
281  * backwards-compatibility needs the device instance have to be published too
282  * early, which requires unpretty global locking to make safe and is therefore
283  * only support for existing drivers not yet converted to the new scheme.
284  *
285  * When cleaning up a device instance everything needs to be done in reverse:
286  * First unpublish the device instance with drm_dev_unregister(). Then clean up
287  * any other resources allocated at device initialization and drop the driver's
288  * reference to &drm_device using drm_dev_put().
289  *
290  * Note that the lifetime rules for &drm_device instance has still a lot of
291  * historical baggage. Hence use the reference counting provided by
292  * drm_dev_get() and drm_dev_put() only carefully.
293  *
294  * Display driver example
295  * ~~~~~~~~~~~~~~~~~~~~~~
296  *
297  * The following example shows a typical structure of a DRM display driver.
298  * The example focus on the probe() function and the other functions that is
299  * almost always present and serves as a demonstration of devm_drm_dev_init()
300  * usage with its accompanying drm_driver->release callback.
301  *
302  * .. code-block:: c
303  *
304  *	struct driver_device {
305  *		struct drm_device drm;
306  *		void *userspace_facing;
307  *		struct clk *pclk;
308  *	};
309  *
310  *	static void driver_drm_release(struct drm_device *drm)
311  *	{
312  *		struct driver_device *priv = container_of(...);
313  *
314  *		drm_mode_config_cleanup(drm);
315  *		drm_dev_fini(drm);
316  *		kfree(priv->userspace_facing);
317  *		kfree(priv);
318  *	}
319  *
320  *	static struct drm_driver driver_drm_driver = {
321  *		[...]
322  *		.release = driver_drm_release,
323  *	};
324  *
325  *	static int driver_probe(struct platform_device *pdev)
326  *	{
327  *		struct driver_device *priv;
328  *		struct drm_device *drm;
329  *		int ret;
330  *
331  *		// devm_kzalloc() can't be used here because the drm_device '
332  *		// lifetime can exceed the device lifetime if driver unbind
333  *		// happens when userspace still has open file descriptors.
334  *		priv = kzalloc(sizeof(*priv), GFP_KERNEL);
335  *		if (!priv)
336  *			return -ENOMEM;
337  *
338  *		drm = &priv->drm;
339  *
340  *		ret = devm_drm_dev_init(&pdev->dev, drm, &driver_drm_driver);
341  *		if (ret) {
342  *			kfree(drm);
343  *			return ret;
344  *		}
345  *
346  *		drm_mode_config_init(drm);
347  *
348  *		priv->userspace_facing = kzalloc(..., GFP_KERNEL);
349  *		if (!priv->userspace_facing)
350  *			return -ENOMEM;
351  *
352  *		priv->pclk = devm_clk_get(dev, "PCLK");
353  *		if (IS_ERR(priv->pclk))
354  *			return PTR_ERR(priv->pclk);
355  *
356  *		// Further setup, display pipeline etc
357  *
358  *		platform_set_drvdata(pdev, drm);
359  *
360  *		drm_mode_config_reset(drm);
361  *
362  *		ret = drm_dev_register(drm);
363  *		if (ret)
364  *			return ret;
365  *
366  *		drm_fbdev_generic_setup(drm, 32);
367  *
368  *		return 0;
369  *	}
370  *
371  *	// This function is called before the devm_ resources are released
372  *	static int driver_remove(struct platform_device *pdev)
373  *	{
374  *		struct drm_device *drm = platform_get_drvdata(pdev);
375  *
376  *		drm_dev_unregister(drm);
377  *		drm_atomic_helper_shutdown(drm)
378  *
379  *		return 0;
380  *	}
381  *
382  *	// This function is called on kernel restart and shutdown
383  *	static void driver_shutdown(struct platform_device *pdev)
384  *	{
385  *		drm_atomic_helper_shutdown(platform_get_drvdata(pdev));
386  *	}
387  *
388  *	static int __maybe_unused driver_pm_suspend(struct device *dev)
389  *	{
390  *		return drm_mode_config_helper_suspend(dev_get_drvdata(dev));
391  *	}
392  *
393  *	static int __maybe_unused driver_pm_resume(struct device *dev)
394  *	{
395  *		drm_mode_config_helper_resume(dev_get_drvdata(dev));
396  *
397  *		return 0;
398  *	}
399  *
400  *	static const struct dev_pm_ops driver_pm_ops = {
401  *		SET_SYSTEM_SLEEP_PM_OPS(driver_pm_suspend, driver_pm_resume)
402  *	};
403  *
404  *	static struct platform_driver driver_driver = {
405  *		.driver = {
406  *			[...]
407  *			.pm = &driver_pm_ops,
408  *		},
409  *		.probe = driver_probe,
410  *		.remove = driver_remove,
411  *		.shutdown = driver_shutdown,
412  *	};
413  *	module_platform_driver(driver_driver);
414  *
415  * Drivers that want to support device unplugging (USB, DT overlay unload) should
416  * use drm_dev_unplug() instead of drm_dev_unregister(). The driver must protect
417  * regions that is accessing device resources to prevent use after they're
418  * released. This is done using drm_dev_enter() and drm_dev_exit(). There is one
419  * shortcoming however, drm_dev_unplug() marks the drm_device as unplugged before
420  * drm_atomic_helper_shutdown() is called. This means that if the disable code
421  * paths are protected, they will not run on regular driver module unload,
422  * possibily leaving the hardware enabled.
423  */
424 
425 /**
426  * drm_put_dev - Unregister and release a DRM device
427  * @dev: DRM device
428  *
429  * Called at module unload time or when a PCI device is unplugged.
430  *
431  * Cleans up all DRM device, calling drm_lastclose().
432  *
433  * Note: Use of this function is deprecated. It will eventually go away
434  * completely.  Please use drm_dev_unregister() and drm_dev_put() explicitly
435  * instead to make sure that the device isn't userspace accessible any more
436  * while teardown is in progress, ensuring that userspace can't access an
437  * inconsistent state.
438  */
439 void drm_put_dev(struct drm_device *dev)
440 {
441 	DRM_DEBUG("\n");
442 
443 	if (!dev) {
444 		DRM_ERROR("cleanup called no dev\n");
445 		return;
446 	}
447 
448 	drm_dev_unregister(dev);
449 	drm_dev_put(dev);
450 }
451 EXPORT_SYMBOL(drm_put_dev);
452 
453 /**
454  * drm_dev_enter - Enter device critical section
455  * @dev: DRM device
456  * @idx: Pointer to index that will be passed to the matching drm_dev_exit()
457  *
458  * This function marks and protects the beginning of a section that should not
459  * be entered after the device has been unplugged. The section end is marked
460  * with drm_dev_exit(). Calls to this function can be nested.
461  *
462  * Returns:
463  * True if it is OK to enter the section, false otherwise.
464  */
465 bool drm_dev_enter(struct drm_device *dev, int *idx)
466 {
467 	*idx = srcu_read_lock(&drm_unplug_srcu);
468 
469 	if (dev->unplugged) {
470 		srcu_read_unlock(&drm_unplug_srcu, *idx);
471 		return false;
472 	}
473 
474 	return true;
475 }
476 EXPORT_SYMBOL(drm_dev_enter);
477 
478 /**
479  * drm_dev_exit - Exit device critical section
480  * @idx: index returned from drm_dev_enter()
481  *
482  * This function marks the end of a section that should not be entered after
483  * the device has been unplugged.
484  */
485 void drm_dev_exit(int idx)
486 {
487 	srcu_read_unlock(&drm_unplug_srcu, idx);
488 }
489 EXPORT_SYMBOL(drm_dev_exit);
490 
491 /**
492  * drm_dev_unplug - unplug a DRM device
493  * @dev: DRM device
494  *
495  * This unplugs a hotpluggable DRM device, which makes it inaccessible to
496  * userspace operations. Entry-points can use drm_dev_enter() and
497  * drm_dev_exit() to protect device resources in a race free manner. This
498  * essentially unregisters the device like drm_dev_unregister(), but can be
499  * called while there are still open users of @dev.
500  */
501 void drm_dev_unplug(struct drm_device *dev)
502 {
503 	/*
504 	 * After synchronizing any critical read section is guaranteed to see
505 	 * the new value of ->unplugged, and any critical section which might
506 	 * still have seen the old value of ->unplugged is guaranteed to have
507 	 * finished.
508 	 */
509 	dev->unplugged = true;
510 	synchronize_srcu(&drm_unplug_srcu);
511 
512 	drm_dev_unregister(dev);
513 }
514 EXPORT_SYMBOL(drm_dev_unplug);
515 
516 /*
517  * DRM internal mount
518  * We want to be able to allocate our own "struct address_space" to control
519  * memory-mappings in VRAM (or stolen RAM, ...). However, core MM does not allow
520  * stand-alone address_space objects, so we need an underlying inode. As there
521  * is no way to allocate an independent inode easily, we need a fake internal
522  * VFS mount-point.
523  *
524  * The drm_fs_inode_new() function allocates a new inode, drm_fs_inode_free()
525  * frees it again. You are allowed to use iget() and iput() to get references to
526  * the inode. But each drm_fs_inode_new() call must be paired with exactly one
527  * drm_fs_inode_free() call (which does not have to be the last iput()).
528  * We use drm_fs_inode_*() to manage our internal VFS mount-point and share it
529  * between multiple inode-users. You could, technically, call
530  * iget() + drm_fs_inode_free() directly after alloc and sometime later do an
531  * iput(), but this way you'd end up with a new vfsmount for each inode.
532  */
533 
534 static int drm_fs_cnt;
535 static struct vfsmount *drm_fs_mnt;
536 
537 static int drm_fs_init_fs_context(struct fs_context *fc)
538 {
539 	return init_pseudo(fc, 0x010203ff) ? 0 : -ENOMEM;
540 }
541 
542 static struct file_system_type drm_fs_type = {
543 	.name		= "drm",
544 	.owner		= THIS_MODULE,
545 	.init_fs_context = drm_fs_init_fs_context,
546 	.kill_sb	= kill_anon_super,
547 };
548 
549 static struct inode *drm_fs_inode_new(void)
550 {
551 	struct inode *inode;
552 	int r;
553 
554 	r = simple_pin_fs(&drm_fs_type, &drm_fs_mnt, &drm_fs_cnt);
555 	if (r < 0) {
556 		DRM_ERROR("Cannot mount pseudo fs: %d\n", r);
557 		return ERR_PTR(r);
558 	}
559 
560 	inode = alloc_anon_inode(drm_fs_mnt->mnt_sb);
561 	if (IS_ERR(inode))
562 		simple_release_fs(&drm_fs_mnt, &drm_fs_cnt);
563 
564 	return inode;
565 }
566 
567 static void drm_fs_inode_free(struct inode *inode)
568 {
569 	if (inode) {
570 		iput(inode);
571 		simple_release_fs(&drm_fs_mnt, &drm_fs_cnt);
572 	}
573 }
574 
575 /**
576  * DOC: component helper usage recommendations
577  *
578  * DRM drivers that drive hardware where a logical device consists of a pile of
579  * independent hardware blocks are recommended to use the :ref:`component helper
580  * library<component>`. For consistency and better options for code reuse the
581  * following guidelines apply:
582  *
583  *  - The entire device initialization procedure should be run from the
584  *    &component_master_ops.master_bind callback, starting with drm_dev_init(),
585  *    then binding all components with component_bind_all() and finishing with
586  *    drm_dev_register().
587  *
588  *  - The opaque pointer passed to all components through component_bind_all()
589  *    should point at &struct drm_device of the device instance, not some driver
590  *    specific private structure.
591  *
592  *  - The component helper fills the niche where further standardization of
593  *    interfaces is not practical. When there already is, or will be, a
594  *    standardized interface like &drm_bridge or &drm_panel, providing its own
595  *    functions to find such components at driver load time, like
596  *    drm_of_find_panel_or_bridge(), then the component helper should not be
597  *    used.
598  */
599 
600 /**
601  * drm_dev_init - Initialise new DRM device
602  * @dev: DRM device
603  * @driver: DRM driver
604  * @parent: Parent device object
605  *
606  * Initialize a new DRM device. No device registration is done.
607  * Call drm_dev_register() to advertice the device to user space and register it
608  * with other core subsystems. This should be done last in the device
609  * initialization sequence to make sure userspace can't access an inconsistent
610  * state.
611  *
612  * The initial ref-count of the object is 1. Use drm_dev_get() and
613  * drm_dev_put() to take and drop further ref-counts.
614  *
615  * It is recommended that drivers embed &struct drm_device into their own device
616  * structure.
617  *
618  * Drivers that do not want to allocate their own device struct
619  * embedding &struct drm_device can call drm_dev_alloc() instead. For drivers
620  * that do embed &struct drm_device it must be placed first in the overall
621  * structure, and the overall structure must be allocated using kmalloc(): The
622  * drm core's release function unconditionally calls kfree() on the @dev pointer
623  * when the final reference is released. To override this behaviour, and so
624  * allow embedding of the drm_device inside the driver's device struct at an
625  * arbitrary offset, you must supply a &drm_driver.release callback and control
626  * the finalization explicitly.
627  *
628  * RETURNS:
629  * 0 on success, or error code on failure.
630  */
631 int drm_dev_init(struct drm_device *dev,
632 		 struct drm_driver *driver,
633 		 struct device *parent)
634 {
635 	int ret;
636 
637 	if (!drm_core_init_complete) {
638 		DRM_ERROR("DRM core is not initialized\n");
639 		return -ENODEV;
640 	}
641 
642 	BUG_ON(!parent);
643 
644 	kref_init(&dev->ref);
645 	dev->dev = get_device(parent);
646 	dev->driver = driver;
647 
648 	/* no per-device feature limits by default */
649 	dev->driver_features = ~0u;
650 
651 	drm_legacy_init_members(dev);
652 	INIT_LIST_HEAD(&dev->filelist);
653 	INIT_LIST_HEAD(&dev->filelist_internal);
654 	INIT_LIST_HEAD(&dev->clientlist);
655 	INIT_LIST_HEAD(&dev->vblank_event_list);
656 
657 	spin_lock_init(&dev->event_lock);
658 	mutex_init(&dev->struct_mutex);
659 	mutex_init(&dev->filelist_mutex);
660 	mutex_init(&dev->clientlist_mutex);
661 	mutex_init(&dev->master_mutex);
662 
663 	dev->anon_inode = drm_fs_inode_new();
664 	if (IS_ERR(dev->anon_inode)) {
665 		ret = PTR_ERR(dev->anon_inode);
666 		DRM_ERROR("Cannot allocate anonymous inode: %d\n", ret);
667 		goto err_free;
668 	}
669 
670 	if (drm_core_check_feature(dev, DRIVER_RENDER)) {
671 		ret = drm_minor_alloc(dev, DRM_MINOR_RENDER);
672 		if (ret)
673 			goto err_minors;
674 	}
675 
676 	ret = drm_minor_alloc(dev, DRM_MINOR_PRIMARY);
677 	if (ret)
678 		goto err_minors;
679 
680 	ret = drm_legacy_create_map_hash(dev);
681 	if (ret)
682 		goto err_minors;
683 
684 	drm_legacy_ctxbitmap_init(dev);
685 
686 	if (drm_core_check_feature(dev, DRIVER_GEM)) {
687 		ret = drm_gem_init(dev);
688 		if (ret) {
689 			DRM_ERROR("Cannot initialize graphics execution manager (GEM)\n");
690 			goto err_ctxbitmap;
691 		}
692 	}
693 
694 	ret = drm_dev_set_unique(dev, dev_name(parent));
695 	if (ret)
696 		goto err_setunique;
697 
698 	return 0;
699 
700 err_setunique:
701 	if (drm_core_check_feature(dev, DRIVER_GEM))
702 		drm_gem_destroy(dev);
703 err_ctxbitmap:
704 	drm_legacy_ctxbitmap_cleanup(dev);
705 	drm_legacy_remove_map_hash(dev);
706 err_minors:
707 	drm_minor_free(dev, DRM_MINOR_PRIMARY);
708 	drm_minor_free(dev, DRM_MINOR_RENDER);
709 	drm_fs_inode_free(dev->anon_inode);
710 err_free:
711 	put_device(dev->dev);
712 	mutex_destroy(&dev->master_mutex);
713 	mutex_destroy(&dev->clientlist_mutex);
714 	mutex_destroy(&dev->filelist_mutex);
715 	mutex_destroy(&dev->struct_mutex);
716 	drm_legacy_destroy_members(dev);
717 	return ret;
718 }
719 EXPORT_SYMBOL(drm_dev_init);
720 
721 static void devm_drm_dev_init_release(void *data)
722 {
723 	drm_dev_put(data);
724 }
725 
726 /**
727  * devm_drm_dev_init - Resource managed drm_dev_init()
728  * @parent: Parent device object
729  * @dev: DRM device
730  * @driver: DRM driver
731  *
732  * Managed drm_dev_init(). The DRM device initialized with this function is
733  * automatically put on driver detach using drm_dev_put(). You must supply a
734  * &drm_driver.release callback to control the finalization explicitly.
735  *
736  * RETURNS:
737  * 0 on success, or error code on failure.
738  */
739 int devm_drm_dev_init(struct device *parent,
740 		      struct drm_device *dev,
741 		      struct drm_driver *driver)
742 {
743 	int ret;
744 
745 	if (WARN_ON(!parent || !driver->release))
746 		return -EINVAL;
747 
748 	ret = drm_dev_init(dev, driver, parent);
749 	if (ret)
750 		return ret;
751 
752 	ret = devm_add_action(parent, devm_drm_dev_init_release, dev);
753 	if (ret)
754 		devm_drm_dev_init_release(dev);
755 
756 	return ret;
757 }
758 EXPORT_SYMBOL(devm_drm_dev_init);
759 
760 /**
761  * drm_dev_fini - Finalize a dead DRM device
762  * @dev: DRM device
763  *
764  * Finalize a dead DRM device. This is the converse to drm_dev_init() and
765  * frees up all data allocated by it. All driver private data should be
766  * finalized first. Note that this function does not free the @dev, that is
767  * left to the caller.
768  *
769  * The ref-count of @dev must be zero, and drm_dev_fini() should only be called
770  * from a &drm_driver.release callback.
771  */
772 void drm_dev_fini(struct drm_device *dev)
773 {
774 	drm_vblank_cleanup(dev);
775 
776 	if (drm_core_check_feature(dev, DRIVER_GEM))
777 		drm_gem_destroy(dev);
778 
779 	drm_legacy_ctxbitmap_cleanup(dev);
780 	drm_legacy_remove_map_hash(dev);
781 	drm_fs_inode_free(dev->anon_inode);
782 
783 	drm_minor_free(dev, DRM_MINOR_PRIMARY);
784 	drm_minor_free(dev, DRM_MINOR_RENDER);
785 
786 	put_device(dev->dev);
787 
788 	mutex_destroy(&dev->master_mutex);
789 	mutex_destroy(&dev->clientlist_mutex);
790 	mutex_destroy(&dev->filelist_mutex);
791 	mutex_destroy(&dev->struct_mutex);
792 	drm_legacy_destroy_members(dev);
793 	kfree(dev->unique);
794 }
795 EXPORT_SYMBOL(drm_dev_fini);
796 
797 /**
798  * drm_dev_alloc - Allocate new DRM device
799  * @driver: DRM driver to allocate device for
800  * @parent: Parent device object
801  *
802  * Allocate and initialize a new DRM device. No device registration is done.
803  * Call drm_dev_register() to advertice the device to user space and register it
804  * with other core subsystems. This should be done last in the device
805  * initialization sequence to make sure userspace can't access an inconsistent
806  * state.
807  *
808  * The initial ref-count of the object is 1. Use drm_dev_get() and
809  * drm_dev_put() to take and drop further ref-counts.
810  *
811  * Note that for purely virtual devices @parent can be NULL.
812  *
813  * Drivers that wish to subclass or embed &struct drm_device into their
814  * own struct should look at using drm_dev_init() instead.
815  *
816  * RETURNS:
817  * Pointer to new DRM device, or ERR_PTR on failure.
818  */
819 struct drm_device *drm_dev_alloc(struct drm_driver *driver,
820 				 struct device *parent)
821 {
822 	struct drm_device *dev;
823 	int ret;
824 
825 	dev = kzalloc(sizeof(*dev), GFP_KERNEL);
826 	if (!dev)
827 		return ERR_PTR(-ENOMEM);
828 
829 	ret = drm_dev_init(dev, driver, parent);
830 	if (ret) {
831 		kfree(dev);
832 		return ERR_PTR(ret);
833 	}
834 
835 	return dev;
836 }
837 EXPORT_SYMBOL(drm_dev_alloc);
838 
839 static void drm_dev_release(struct kref *ref)
840 {
841 	struct drm_device *dev = container_of(ref, struct drm_device, ref);
842 
843 	if (dev->driver->release) {
844 		dev->driver->release(dev);
845 	} else {
846 		drm_dev_fini(dev);
847 		kfree(dev);
848 	}
849 }
850 
851 /**
852  * drm_dev_get - Take reference of a DRM device
853  * @dev: device to take reference of or NULL
854  *
855  * This increases the ref-count of @dev by one. You *must* already own a
856  * reference when calling this. Use drm_dev_put() to drop this reference
857  * again.
858  *
859  * This function never fails. However, this function does not provide *any*
860  * guarantee whether the device is alive or running. It only provides a
861  * reference to the object and the memory associated with it.
862  */
863 void drm_dev_get(struct drm_device *dev)
864 {
865 	if (dev)
866 		kref_get(&dev->ref);
867 }
868 EXPORT_SYMBOL(drm_dev_get);
869 
870 /**
871  * drm_dev_put - Drop reference of a DRM device
872  * @dev: device to drop reference of or NULL
873  *
874  * This decreases the ref-count of @dev by one. The device is destroyed if the
875  * ref-count drops to zero.
876  */
877 void drm_dev_put(struct drm_device *dev)
878 {
879 	if (dev)
880 		kref_put(&dev->ref, drm_dev_release);
881 }
882 EXPORT_SYMBOL(drm_dev_put);
883 
884 static int create_compat_control_link(struct drm_device *dev)
885 {
886 	struct drm_minor *minor;
887 	char *name;
888 	int ret;
889 
890 	if (!drm_core_check_feature(dev, DRIVER_MODESET))
891 		return 0;
892 
893 	minor = *drm_minor_get_slot(dev, DRM_MINOR_PRIMARY);
894 	if (!minor)
895 		return 0;
896 
897 	/*
898 	 * Some existing userspace out there uses the existing of the controlD*
899 	 * sysfs files to figure out whether it's a modeset driver. It only does
900 	 * readdir, hence a symlink is sufficient (and the least confusing
901 	 * option). Otherwise controlD* is entirely unused.
902 	 *
903 	 * Old controlD chardev have been allocated in the range
904 	 * 64-127.
905 	 */
906 	name = kasprintf(GFP_KERNEL, "controlD%d", minor->index + 64);
907 	if (!name)
908 		return -ENOMEM;
909 
910 	ret = sysfs_create_link(minor->kdev->kobj.parent,
911 				&minor->kdev->kobj,
912 				name);
913 
914 	kfree(name);
915 
916 	return ret;
917 }
918 
919 static void remove_compat_control_link(struct drm_device *dev)
920 {
921 	struct drm_minor *minor;
922 	char *name;
923 
924 	if (!drm_core_check_feature(dev, DRIVER_MODESET))
925 		return;
926 
927 	minor = *drm_minor_get_slot(dev, DRM_MINOR_PRIMARY);
928 	if (!minor)
929 		return;
930 
931 	name = kasprintf(GFP_KERNEL, "controlD%d", minor->index + 64);
932 	if (!name)
933 		return;
934 
935 	sysfs_remove_link(minor->kdev->kobj.parent, name);
936 
937 	kfree(name);
938 }
939 
940 /**
941  * drm_dev_register - Register DRM device
942  * @dev: Device to register
943  * @flags: Flags passed to the driver's .load() function
944  *
945  * Register the DRM device @dev with the system, advertise device to user-space
946  * and start normal device operation. @dev must be initialized via drm_dev_init()
947  * previously.
948  *
949  * Never call this twice on any device!
950  *
951  * NOTE: To ensure backward compatibility with existing drivers method this
952  * function calls the &drm_driver.load method after registering the device
953  * nodes, creating race conditions. Usage of the &drm_driver.load methods is
954  * therefore deprecated, drivers must perform all initialization before calling
955  * drm_dev_register().
956  *
957  * RETURNS:
958  * 0 on success, negative error code on failure.
959  */
960 int drm_dev_register(struct drm_device *dev, unsigned long flags)
961 {
962 	struct drm_driver *driver = dev->driver;
963 	int ret;
964 
965 	mutex_lock(&drm_global_mutex);
966 
967 	ret = drm_minor_register(dev, DRM_MINOR_RENDER);
968 	if (ret)
969 		goto err_minors;
970 
971 	ret = drm_minor_register(dev, DRM_MINOR_PRIMARY);
972 	if (ret)
973 		goto err_minors;
974 
975 	ret = create_compat_control_link(dev);
976 	if (ret)
977 		goto err_minors;
978 
979 	if (dev->driver->load) {
980 		ret = dev->driver->load(dev, flags);
981 		if (ret)
982 			goto err_minors;
983 	}
984 
985 	dev->registered = true;
986 
987 	if (drm_core_check_feature(dev, DRIVER_MODESET))
988 		drm_modeset_register_all(dev);
989 
990 	ret = 0;
991 
992 	DRM_INFO("Initialized %s %d.%d.%d %s for %s on minor %d\n",
993 		 driver->name, driver->major, driver->minor,
994 		 driver->patchlevel, driver->date,
995 		 dev->dev ? dev_name(dev->dev) : "virtual device",
996 		 dev->primary->index);
997 
998 	goto out_unlock;
999 
1000 err_minors:
1001 	remove_compat_control_link(dev);
1002 	drm_minor_unregister(dev, DRM_MINOR_PRIMARY);
1003 	drm_minor_unregister(dev, DRM_MINOR_RENDER);
1004 out_unlock:
1005 	mutex_unlock(&drm_global_mutex);
1006 	return ret;
1007 }
1008 EXPORT_SYMBOL(drm_dev_register);
1009 
1010 /**
1011  * drm_dev_unregister - Unregister DRM device
1012  * @dev: Device to unregister
1013  *
1014  * Unregister the DRM device from the system. This does the reverse of
1015  * drm_dev_register() but does not deallocate the device. The caller must call
1016  * drm_dev_put() to drop their final reference.
1017  *
1018  * A special form of unregistering for hotpluggable devices is drm_dev_unplug(),
1019  * which can be called while there are still open users of @dev.
1020  *
1021  * This should be called first in the device teardown code to make sure
1022  * userspace can't access the device instance any more.
1023  */
1024 void drm_dev_unregister(struct drm_device *dev)
1025 {
1026 	if (drm_core_check_feature(dev, DRIVER_LEGACY))
1027 		drm_lastclose(dev);
1028 
1029 	dev->registered = false;
1030 
1031 	drm_client_dev_unregister(dev);
1032 
1033 	if (drm_core_check_feature(dev, DRIVER_MODESET))
1034 		drm_modeset_unregister_all(dev);
1035 
1036 	if (dev->driver->unload)
1037 		dev->driver->unload(dev);
1038 
1039 	if (dev->agp)
1040 		drm_pci_agp_destroy(dev);
1041 
1042 	drm_legacy_rmmaps(dev);
1043 
1044 	remove_compat_control_link(dev);
1045 	drm_minor_unregister(dev, DRM_MINOR_PRIMARY);
1046 	drm_minor_unregister(dev, DRM_MINOR_RENDER);
1047 }
1048 EXPORT_SYMBOL(drm_dev_unregister);
1049 
1050 /**
1051  * drm_dev_set_unique - Set the unique name of a DRM device
1052  * @dev: device of which to set the unique name
1053  * @name: unique name
1054  *
1055  * Sets the unique name of a DRM device using the specified string. This is
1056  * already done by drm_dev_init(), drivers should only override the default
1057  * unique name for backwards compatibility reasons.
1058  *
1059  * Return: 0 on success or a negative error code on failure.
1060  */
1061 int drm_dev_set_unique(struct drm_device *dev, const char *name)
1062 {
1063 	kfree(dev->unique);
1064 	dev->unique = kstrdup(name, GFP_KERNEL);
1065 
1066 	return dev->unique ? 0 : -ENOMEM;
1067 }
1068 EXPORT_SYMBOL(drm_dev_set_unique);
1069 
1070 /*
1071  * DRM Core
1072  * The DRM core module initializes all global DRM objects and makes them
1073  * available to drivers. Once setup, drivers can probe their respective
1074  * devices.
1075  * Currently, core management includes:
1076  *  - The "DRM-Global" key/value database
1077  *  - Global ID management for connectors
1078  *  - DRM major number allocation
1079  *  - DRM minor management
1080  *  - DRM sysfs class
1081  *  - DRM debugfs root
1082  *
1083  * Furthermore, the DRM core provides dynamic char-dev lookups. For each
1084  * interface registered on a DRM device, you can request minor numbers from DRM
1085  * core. DRM core takes care of major-number management and char-dev
1086  * registration. A stub ->open() callback forwards any open() requests to the
1087  * registered minor.
1088  */
1089 
1090 static int drm_stub_open(struct inode *inode, struct file *filp)
1091 {
1092 	const struct file_operations *new_fops;
1093 	struct drm_minor *minor;
1094 	int err;
1095 
1096 	DRM_DEBUG("\n");
1097 
1098 	mutex_lock(&drm_global_mutex);
1099 	minor = drm_minor_acquire(iminor(inode));
1100 	if (IS_ERR(minor)) {
1101 		err = PTR_ERR(minor);
1102 		goto out_unlock;
1103 	}
1104 
1105 	new_fops = fops_get(minor->dev->driver->fops);
1106 	if (!new_fops) {
1107 		err = -ENODEV;
1108 		goto out_release;
1109 	}
1110 
1111 	replace_fops(filp, new_fops);
1112 	if (filp->f_op->open)
1113 		err = filp->f_op->open(inode, filp);
1114 	else
1115 		err = 0;
1116 
1117 out_release:
1118 	drm_minor_release(minor);
1119 out_unlock:
1120 	mutex_unlock(&drm_global_mutex);
1121 	return err;
1122 }
1123 
1124 static const struct file_operations drm_stub_fops = {
1125 	.owner = THIS_MODULE,
1126 	.open = drm_stub_open,
1127 	.llseek = noop_llseek,
1128 };
1129 
1130 static void drm_core_exit(void)
1131 {
1132 	unregister_chrdev(DRM_MAJOR, "drm");
1133 	debugfs_remove(drm_debugfs_root);
1134 	drm_sysfs_destroy();
1135 	idr_destroy(&drm_minors_idr);
1136 	drm_connector_ida_destroy();
1137 }
1138 
1139 static int __init drm_core_init(void)
1140 {
1141 	int ret;
1142 
1143 	drm_connector_ida_init();
1144 	idr_init(&drm_minors_idr);
1145 
1146 	ret = drm_sysfs_init();
1147 	if (ret < 0) {
1148 		DRM_ERROR("Cannot create DRM class: %d\n", ret);
1149 		goto error;
1150 	}
1151 
1152 	drm_debugfs_root = debugfs_create_dir("dri", NULL);
1153 
1154 	ret = register_chrdev(DRM_MAJOR, "drm", &drm_stub_fops);
1155 	if (ret < 0)
1156 		goto error;
1157 
1158 	drm_core_init_complete = true;
1159 
1160 	DRM_DEBUG("Initialized\n");
1161 	return 0;
1162 
1163 error:
1164 	drm_core_exit();
1165 	return ret;
1166 }
1167 
1168 module_init(drm_core_init);
1169 module_exit(drm_core_exit);
1170