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