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 */
  53unsigned int drm_debug = 0;
  54EXPORT_SYMBOL(drm_debug);
  55
  56MODULE_AUTHOR("Gareth Hughes, Leif Delgass, José Fonseca, Jon Smirl");
  57MODULE_DESCRIPTION("DRM shared core routines");
  58MODULE_LICENSE("GPL and additional rights");
  59MODULE_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)");
  68module_param_named(debug, drm_debug, int, 0600);
  69
  70static DEFINE_SPINLOCK(drm_minor_lock);
  71static 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 */
  80static bool drm_core_init_complete = false;
  81
  82static struct dentry *drm_debugfs_root;
  83
  84DEFINE_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
  99static 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
 112static 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
 149err_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);
 153err_free:
 154	kfree(minor);
 155	return r;
 156}
 157
 158static 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
 178static 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
 208err_debugfs:
 209	drm_debugfs_cleanup(minor);
 210	return ret;
 211}
 212
 213static 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 */
 241struct 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
 262void 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 */
 439void 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}
 451EXPORT_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 */
 465bool 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}
 476EXPORT_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 */
 485void drm_dev_exit(int idx)
 486{
 487	srcu_read_unlock(&drm_unplug_srcu, idx);
 488}
 489EXPORT_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 */
 501void 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}
 514EXPORT_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
 534static int drm_fs_cnt;
 535static struct vfsmount *drm_fs_mnt;
 536
 537static int drm_fs_init_fs_context(struct fs_context *fc)
 
 
 
 
 
 
 
 
 
 538{
 539	return init_pseudo(fc, 0x010203ff) ? 0 : -ENOMEM;
 
 
 
 
 540}
 541
 542static 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
 549static 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
 567static 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 */
 631int 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
 700err_setunique:
 701	if (drm_core_check_feature(dev, DRIVER_GEM))
 702		drm_gem_destroy(dev);
 703err_ctxbitmap:
 704	drm_legacy_ctxbitmap_cleanup(dev);
 705	drm_legacy_remove_map_hash(dev);
 706err_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);
 710err_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}
 719EXPORT_SYMBOL(drm_dev_init);
 720
 721static 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 */
 739int 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}
 758EXPORT_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 */
 772void 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}
 795EXPORT_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 */
 819struct 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}
 837EXPORT_SYMBOL(drm_dev_alloc);
 838
 839static 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 */
 863void drm_dev_get(struct drm_device *dev)
 864{
 865	if (dev)
 866		kref_get(&dev->ref);
 867}
 868EXPORT_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 */
 877void drm_dev_put(struct drm_device *dev)
 878{
 879	if (dev)
 880		kref_put(&dev->ref, drm_dev_release);
 881}
 882EXPORT_SYMBOL(drm_dev_put);
 883
 884static 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
 919static 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 */
 960int 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	dev->registered = true;
 980
 981	if (dev->driver->load) {
 982		ret = dev->driver->load(dev, flags);
 983		if (ret)
 984			goto err_minors;
 985	}
 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
1000err_minors:
1001	remove_compat_control_link(dev);
1002	drm_minor_unregister(dev, DRM_MINOR_PRIMARY);
1003	drm_minor_unregister(dev, DRM_MINOR_RENDER);
 
1004out_unlock:
1005	mutex_unlock(&drm_global_mutex);
1006	return ret;
1007}
1008EXPORT_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 */
1024void 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}
1048EXPORT_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 */
1061int 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}
1068EXPORT_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
1090static 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
1117out_release:
1118	drm_minor_release(minor);
1119out_unlock:
1120	mutex_unlock(&drm_global_mutex);
1121	return err;
1122}
1123
1124static const struct file_operations drm_stub_fops = {
1125	.owner = THIS_MODULE,
1126	.open = drm_stub_open,
1127	.llseek = noop_llseek,
1128};
1129
1130static 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
1139static 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
1163error:
1164	drm_core_exit();
1165	return ret;
1166}
1167
1168module_init(drm_core_init);
1169module_exit(drm_core_exit);