Adding upstream version 4.19.249.upstream/4.19.249

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

1 files changed, 1013 insertions, 0 deletions

diff --git a/drivers/gpu/drm/drm_drv.c b/drivers/gpu/drm/drm_drv.c
new file mode 100644
index 000000000..d8ae4ca12
--- /dev/null
+++ b/drivers/gpu/drm/drm_drv.c
@@ -0,0 +1,1013 @@
+/*
+ * Created: Fri Jan 19 10:48:35 2001 by faith@acm.org
+ *
+ * Copyright 2001 VA Linux Systems, Inc., Sunnyvale, California.
+ * All Rights Reserved.
+ *
+ * Author Rickard E. (Rik) Faith <faith@valinux.com>
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a
+ * copy of this software and associated documentation files (the "Software"),
+ * to deal in the Software without restriction, including without limitation
+ * the rights to use, copy, modify, merge, publish, distribute, sublicense,
+ * and/or sell copies of the Software, and to permit persons to whom the
+ * Software is furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice (including the next
+ * paragraph) shall be included in all copies or substantial portions of the
+ * Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.  IN NO EVENT SHALL
+ * PRECISION INSIGHT AND/OR ITS SUPPLIERS BE LIABLE FOR ANY CLAIM, DAMAGES OR
+ * OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE,
+ * ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
+ * DEALINGS IN THE SOFTWARE.
+ */
+
+#include <linux/debugfs.h>
+#include <linux/fs.h>
+#include <linux/module.h>
+#include <linux/moduleparam.h>
+#include <linux/mount.h>
+#include <linux/slab.h>
+#include <linux/srcu.h>
+
+#include <drm/drm_client.h>
+#include <drm/drm_drv.h>
+#include <drm/drmP.h>
+
+#include "drm_crtc_internal.h"
+#include "drm_legacy.h"
+#include "drm_internal.h"
+#include "drm_crtc_internal.h"
+
+/*
+ * drm_debug: Enable debug output.
+ * Bitmask of DRM_UT_x. See include/drm/drmP.h for details.
+ */
+unsigned int drm_debug = 0;
+EXPORT_SYMBOL(drm_debug);
+
+MODULE_AUTHOR("Gareth Hughes, Leif Delgass, José Fonseca, Jon Smirl");
+MODULE_DESCRIPTION("DRM shared core routines");
+MODULE_LICENSE("GPL and additional rights");
+MODULE_PARM_DESC(debug, "Enable debug output, where each bit enables a debug category.\n"
+"\t\tBit 0 (0x01)  will enable CORE messages (drm core code)\n"
+"\t\tBit 1 (0x02)  will enable DRIVER messages (drm controller code)\n"
+"\t\tBit 2 (0x04)  will enable KMS messages (modesetting code)\n"
+"\t\tBit 3 (0x08)  will enable PRIME messages (prime code)\n"
+"\t\tBit 4 (0x10)  will enable ATOMIC messages (atomic code)\n"
+"\t\tBit 5 (0x20)  will enable VBL messages (vblank code)\n"
+"\t\tBit 7 (0x80)  will enable LEASE messages (leasing code)\n"
+"\t\tBit 8 (0x100) will enable DP messages (displayport code)");
+module_param_named(debug, drm_debug, int, 0600);
+
+static DEFINE_SPINLOCK(drm_minor_lock);
+static struct idr drm_minors_idr;
+
+/*
+ * If the drm core fails to init for whatever reason,
+ * we should prevent any drivers from registering with it.
+ * It's best to check this at drm_dev_init(), as some drivers
+ * prefer to embed struct drm_device into their own device
+ * structure and call drm_dev_init() themselves.
+ */
+static bool drm_core_init_complete = false;
+
+static struct dentry *drm_debugfs_root;
+
+DEFINE_STATIC_SRCU(drm_unplug_srcu);
+
+/*
+ * DRM Minors
+ * A DRM device can provide several char-dev interfaces on the DRM-Major. Each
+ * of them is represented by a drm_minor object. Depending on the capabilities
+ * of the device-driver, different interfaces are registered.
+ *
+ * Minors can be accessed via dev->$minor_name. This pointer is either
+ * NULL or a valid drm_minor pointer and stays valid as long as the device is
+ * valid. This means, DRM minors have the same life-time as the underlying
+ * device. However, this doesn't mean that the minor is active. Minors are
+ * registered and unregistered dynamically according to device-state.
+ */
+
+static struct drm_minor **drm_minor_get_slot(struct drm_device *dev,
+					     unsigned int type)
+{
+	switch (type) {
+	case DRM_MINOR_PRIMARY:
+		return &dev->primary;
+	case DRM_MINOR_RENDER:
+		return &dev->render;
+	default:
+		BUG();
+	}
+}
+
+static int drm_minor_alloc(struct drm_device *dev, unsigned int type)
+{
+	struct drm_minor *minor;
+	unsigned long flags;
+	int r;
+
+	minor = kzalloc(sizeof(*minor), GFP_KERNEL);
+	if (!minor)
+		return -ENOMEM;
+
+	minor->type = type;
+	minor->dev = dev;
+
+	idr_preload(GFP_KERNEL);
+	spin_lock_irqsave(&drm_minor_lock, flags);
+	r = idr_alloc(&drm_minors_idr,
+		      NULL,
+		      64 * type,
+		      64 * (type + 1),
+		      GFP_NOWAIT);
+	spin_unlock_irqrestore(&drm_minor_lock, flags);
+	idr_preload_end();
+
+	if (r < 0)
+		goto err_free;
+
+	minor->index = r;
+
+	minor->kdev = drm_sysfs_minor_alloc(minor);
+	if (IS_ERR(minor->kdev)) {
+		r = PTR_ERR(minor->kdev);
+		goto err_index;
+	}
+
+	*drm_minor_get_slot(dev, type) = minor;
+	return 0;
+
+err_index:
+	spin_lock_irqsave(&drm_minor_lock, flags);
+	idr_remove(&drm_minors_idr, minor->index);
+	spin_unlock_irqrestore(&drm_minor_lock, flags);
+err_free:
+	kfree(minor);
+	return r;
+}
+
+static void drm_minor_free(struct drm_device *dev, unsigned int type)
+{
+	struct drm_minor **slot, *minor;
+	unsigned long flags;
+
+	slot = drm_minor_get_slot(dev, type);
+	minor = *slot;
+	if (!minor)
+		return;
+
+	put_device(minor->kdev);
+
+	spin_lock_irqsave(&drm_minor_lock, flags);
+	idr_remove(&drm_minors_idr, minor->index);
+	spin_unlock_irqrestore(&drm_minor_lock, flags);
+
+	kfree(minor);
+	*slot = NULL;
+}
+
+static int drm_minor_register(struct drm_device *dev, unsigned int type)
+{
+	struct drm_minor *minor;
+	unsigned long flags;
+	int ret;
+
+	DRM_DEBUG("\n");
+
+	minor = *drm_minor_get_slot(dev, type);
+	if (!minor)
+		return 0;
+
+	ret = drm_debugfs_init(minor, minor->index, drm_debugfs_root);
+	if (ret) {
+		DRM_ERROR("DRM: Failed to initialize /sys/kernel/debug/dri.\n");
+		goto err_debugfs;
+	}
+
+	ret = device_add(minor->kdev);
+	if (ret)
+		goto err_debugfs;
+
+	/* replace NULL with @minor so lookups will succeed from now on */
+	spin_lock_irqsave(&drm_minor_lock, flags);
+	idr_replace(&drm_minors_idr, minor, minor->index);
+	spin_unlock_irqrestore(&drm_minor_lock, flags);
+
+	DRM_DEBUG("new minor registered %d\n", minor->index);
+	return 0;
+
+err_debugfs:
+	drm_debugfs_cleanup(minor);
+	return ret;
+}
+
+static void drm_minor_unregister(struct drm_device *dev, unsigned int type)
+{
+	struct drm_minor *minor;
+	unsigned long flags;
+
+	minor = *drm_minor_get_slot(dev, type);
+	if (!minor || !device_is_registered(minor->kdev))
+		return;
+
+	/* replace @minor with NULL so lookups will fail from now on */
+	spin_lock_irqsave(&drm_minor_lock, flags);
+	idr_replace(&drm_minors_idr, NULL, minor->index);
+	spin_unlock_irqrestore(&drm_minor_lock, flags);
+
+	device_del(minor->kdev);
+	dev_set_drvdata(minor->kdev, NULL); /* safety belt */
+	drm_debugfs_cleanup(minor);
+}
+
+/*
+ * Looks up the given minor-ID and returns the respective DRM-minor object. The
+ * refence-count of the underlying device is increased so you must release this
+ * object with drm_minor_release().
+ *
+ * As long as you hold this minor, it is guaranteed that the object and the
+ * minor->dev pointer will stay valid! However, the device may get unplugged and
+ * unregistered while you hold the minor.
+ */
+struct drm_minor *drm_minor_acquire(unsigned int minor_id)
+{
+	struct drm_minor *minor;
+	unsigned long flags;
+
+	spin_lock_irqsave(&drm_minor_lock, flags);
+	minor = idr_find(&drm_minors_idr, minor_id);
+	if (minor)
+		drm_dev_get(minor->dev);
+	spin_unlock_irqrestore(&drm_minor_lock, flags);
+
+	if (!minor) {
+		return ERR_PTR(-ENODEV);
+	} else if (drm_dev_is_unplugged(minor->dev)) {
+		drm_dev_put(minor->dev);
+		return ERR_PTR(-ENODEV);
+	}
+
+	return minor;
+}
+
+void drm_minor_release(struct drm_minor *minor)
+{
+	drm_dev_put(minor->dev);
+}
+
+/**
+ * DOC: driver instance overview
+ *
+ * A device instance for a drm driver is represented by &struct drm_device. This
+ * is allocated with drm_dev_alloc(), usually from bus-specific ->probe()
+ * callbacks implemented by the driver. The driver then needs to initialize all
+ * the various subsystems for the drm device like memory management, vblank
+ * handling, modesetting support and intial output configuration plus obviously
+ * initialize all the corresponding hardware bits. An important part of this is
+ * also calling drm_dev_set_unique() to set the userspace-visible unique name of
+ * this device instance. Finally when everything is up and running and ready for
+ * userspace the device instance can be published using drm_dev_register().
+ *
+ * There is also deprecated support for initalizing device instances using
+ * bus-specific helpers and the &drm_driver.load callback. But due to
+ * backwards-compatibility needs the device instance have to be published too
+ * early, which requires unpretty global locking to make safe and is therefore
+ * only support for existing drivers not yet converted to the new scheme.
+ *
+ * When cleaning up a device instance everything needs to be done in reverse:
+ * First unpublish the device instance with drm_dev_unregister(). Then clean up
+ * any other resources allocated at device initialization and drop the driver's
+ * reference to &drm_device using drm_dev_put().
+ *
+ * Note that the lifetime rules for &drm_device instance has still a lot of
+ * historical baggage. Hence use the reference counting provided by
+ * drm_dev_get() and drm_dev_put() only carefully.
+ *
+ * It is recommended that drivers embed &struct drm_device into their own device
+ * structure, which is supported through drm_dev_init().
+ */
+
+/**
+ * drm_put_dev - Unregister and release a DRM device
+ * @dev: DRM device
+ *
+ * Called at module unload time or when a PCI device is unplugged.
+ *
+ * Cleans up all DRM device, calling drm_lastclose().
+ *
+ * Note: Use of this function is deprecated. It will eventually go away
+ * completely.  Please use drm_dev_unregister() and drm_dev_put() explicitly
+ * instead to make sure that the device isn't userspace accessible any more
+ * while teardown is in progress, ensuring that userspace can't access an
+ * inconsistent state.
+ */
+void drm_put_dev(struct drm_device *dev)
+{
+	DRM_DEBUG("\n");
+
+	if (!dev) {
+		DRM_ERROR("cleanup called no dev\n");
+		return;
+	}
+
+	drm_dev_unregister(dev);
+	drm_dev_put(dev);
+}
+EXPORT_SYMBOL(drm_put_dev);
+
+/**
+ * drm_dev_enter - Enter device critical section
+ * @dev: DRM device
+ * @idx: Pointer to index that will be passed to the matching drm_dev_exit()
+ *
+ * This function marks and protects the beginning of a section that should not
+ * be entered after the device has been unplugged. The section end is marked
+ * with drm_dev_exit(). Calls to this function can be nested.
+ *
+ * Returns:
+ * True if it is OK to enter the section, false otherwise.
+ */
+bool drm_dev_enter(struct drm_device *dev, int *idx)
+{
+	*idx = srcu_read_lock(&drm_unplug_srcu);
+
+	if (dev->unplugged) {
+		srcu_read_unlock(&drm_unplug_srcu, *idx);
+		return false;
+	}
+
+	return true;
+}
+EXPORT_SYMBOL(drm_dev_enter);
+
+/**
+ * drm_dev_exit - Exit device critical section
+ * @idx: index returned from drm_dev_enter()
+ *
+ * This function marks the end of a section that should not be entered after
+ * the device has been unplugged.
+ */
+void drm_dev_exit(int idx)
+{
+	srcu_read_unlock(&drm_unplug_srcu, idx);
+}
+EXPORT_SYMBOL(drm_dev_exit);
+
+/**
+ * drm_dev_unplug - unplug a DRM device
+ * @dev: DRM device
+ *
+ * This unplugs a hotpluggable DRM device, which makes it inaccessible to
+ * userspace operations. Entry-points can use drm_dev_enter() and
+ * drm_dev_exit() to protect device resources in a race free manner. This
+ * essentially unregisters the device like drm_dev_unregister(), but can be
+ * called while there are still open users of @dev.
+ */
+void drm_dev_unplug(struct drm_device *dev)
+{
+	/*
+	 * After synchronizing any critical read section is guaranteed to see
+	 * the new value of ->unplugged, and any critical section which might
+	 * still have seen the old value of ->unplugged is guaranteed to have
+	 * finished.
+	 */
+	dev->unplugged = true;
+	synchronize_srcu(&drm_unplug_srcu);
+
+	drm_dev_unregister(dev);
+	drm_dev_put(dev);
+}
+EXPORT_SYMBOL(drm_dev_unplug);
+
+/*
+ * DRM internal mount
+ * We want to be able to allocate our own "struct address_space" to control
+ * memory-mappings in VRAM (or stolen RAM, ...). However, core MM does not allow
+ * stand-alone address_space objects, so we need an underlying inode. As there
+ * is no way to allocate an independent inode easily, we need a fake internal
+ * VFS mount-point.
+ *
+ * The drm_fs_inode_new() function allocates a new inode, drm_fs_inode_free()
+ * frees it again. You are allowed to use iget() and iput() to get references to
+ * the inode. But each drm_fs_inode_new() call must be paired with exactly one
+ * drm_fs_inode_free() call (which does not have to be the last iput()).
+ * We use drm_fs_inode_*() to manage our internal VFS mount-point and share it
+ * between multiple inode-users. You could, technically, call
+ * iget() + drm_fs_inode_free() directly after alloc and sometime later do an
+ * iput(), but this way you'd end up with a new vfsmount for each inode.
+ */
+
+static int drm_fs_cnt;
+static struct vfsmount *drm_fs_mnt;
+
+static const struct dentry_operations drm_fs_dops = {
+	.d_dname	= simple_dname,
+};
+
+static const struct super_operations drm_fs_sops = {
+	.statfs		= simple_statfs,
+};
+
+static struct dentry *drm_fs_mount(struct file_system_type *fs_type, int flags,
+				   const char *dev_name, void *data)
+{
+	return mount_pseudo(fs_type,
+			    "drm:",
+			    &drm_fs_sops,
+			    &drm_fs_dops,
+			    0x010203ff);
+}
+
+static struct file_system_type drm_fs_type = {
+	.name		= "drm",
+	.owner		= THIS_MODULE,
+	.mount		= drm_fs_mount,
+	.kill_sb	= kill_anon_super,
+};
+
+static struct inode *drm_fs_inode_new(void)
+{
+	struct inode *inode;
+	int r;
+
+	r = simple_pin_fs(&drm_fs_type, &drm_fs_mnt, &drm_fs_cnt);
+	if (r < 0) {
+		DRM_ERROR("Cannot mount pseudo fs: %d\n", r);
+		return ERR_PTR(r);
+	}
+
+	inode = alloc_anon_inode(drm_fs_mnt->mnt_sb);
+	if (IS_ERR(inode))
+		simple_release_fs(&drm_fs_mnt, &drm_fs_cnt);
+
+	return inode;
+}
+
+static void drm_fs_inode_free(struct inode *inode)
+{
+	if (inode) {
+		iput(inode);
+		simple_release_fs(&drm_fs_mnt, &drm_fs_cnt);
+	}
+}
+
+/**
+ * drm_dev_init - Initialise new DRM device
+ * @dev: DRM device
+ * @driver: DRM driver
+ * @parent: Parent device object
+ *
+ * Initialize a new DRM device. No device registration is done.
+ * Call drm_dev_register() to advertice the device to user space and register it
+ * with other core subsystems. This should be done last in the device
+ * initialization sequence to make sure userspace can't access an inconsistent
+ * state.
+ *
+ * The initial ref-count of the object is 1. Use drm_dev_get() and
+ * drm_dev_put() to take and drop further ref-counts.
+ *
+ * Note that for purely virtual devices @parent can be NULL.
+ *
+ * Drivers that do not want to allocate their own device struct
+ * embedding &struct drm_device can call drm_dev_alloc() instead. For drivers
+ * that do embed &struct drm_device it must be placed first in the overall
+ * structure, and the overall structure must be allocated using kmalloc(): The
+ * drm core's release function unconditionally calls kfree() on the @dev pointer
+ * when the final reference is released. To override this behaviour, and so
+ * allow embedding of the drm_device inside the driver's device struct at an
+ * arbitrary offset, you must supply a &drm_driver.release callback and control
+ * the finalization explicitly.
+ *
+ * RETURNS:
+ * 0 on success, or error code on failure.
+ */
+int drm_dev_init(struct drm_device *dev,
+		 struct drm_driver *driver,
+		 struct device *parent)
+{
+	int ret;
+
+	if (!drm_core_init_complete) {
+		DRM_ERROR("DRM core is not initialized\n");
+		return -ENODEV;
+	}
+
+	kref_init(&dev->ref);
+	dev->dev = get_device(parent);
+	dev->driver = driver;
+
+	INIT_LIST_HEAD(&dev->filelist);
+	INIT_LIST_HEAD(&dev->filelist_internal);
+	INIT_LIST_HEAD(&dev->clientlist);
+	INIT_LIST_HEAD(&dev->ctxlist);
+	INIT_LIST_HEAD(&dev->vmalist);
+	INIT_LIST_HEAD(&dev->maplist);
+	INIT_LIST_HEAD(&dev->vblank_event_list);
+
+	spin_lock_init(&dev->buf_lock);
+	spin_lock_init(&dev->event_lock);
+	mutex_init(&dev->struct_mutex);
+	mutex_init(&dev->filelist_mutex);
+	mutex_init(&dev->clientlist_mutex);
+	mutex_init(&dev->ctxlist_mutex);
+	mutex_init(&dev->master_mutex);
+
+	dev->anon_inode = drm_fs_inode_new();
+	if (IS_ERR(dev->anon_inode)) {
+		ret = PTR_ERR(dev->anon_inode);
+		DRM_ERROR("Cannot allocate anonymous inode: %d\n", ret);
+		goto err_free;
+	}
+
+	if (drm_core_check_feature(dev, DRIVER_RENDER)) {
+		ret = drm_minor_alloc(dev, DRM_MINOR_RENDER);
+		if (ret)
+			goto err_minors;
+	}
+
+	ret = drm_minor_alloc(dev, DRM_MINOR_PRIMARY);
+	if (ret)
+		goto err_minors;
+
+	ret = drm_ht_create(&dev->map_hash, 12);
+	if (ret)
+		goto err_minors;
+
+	drm_legacy_ctxbitmap_init(dev);
+
+	if (drm_core_check_feature(dev, DRIVER_GEM)) {
+		ret = drm_gem_init(dev);
+		if (ret) {
+			DRM_ERROR("Cannot initialize graphics execution manager (GEM)\n");
+			goto err_ctxbitmap;
+		}
+	}
+
+	/* Use the parent device name as DRM device unique identifier, but fall
+	 * back to the driver name for virtual devices like vgem. */
+	ret = drm_dev_set_unique(dev, parent ? dev_name(parent) : driver->name);
+	if (ret)
+		goto err_setunique;
+
+	return 0;
+
+err_setunique:
+	if (drm_core_check_feature(dev, DRIVER_GEM))
+		drm_gem_destroy(dev);
+err_ctxbitmap:
+	drm_legacy_ctxbitmap_cleanup(dev);
+	drm_ht_remove(&dev->map_hash);
+err_minors:
+	drm_minor_free(dev, DRM_MINOR_PRIMARY);
+	drm_minor_free(dev, DRM_MINOR_RENDER);
+	drm_fs_inode_free(dev->anon_inode);
+err_free:
+	put_device(dev->dev);
+	mutex_destroy(&dev->master_mutex);
+	mutex_destroy(&dev->ctxlist_mutex);
+	mutex_destroy(&dev->clientlist_mutex);
+	mutex_destroy(&dev->filelist_mutex);
+	mutex_destroy(&dev->struct_mutex);
+	return ret;
+}
+EXPORT_SYMBOL(drm_dev_init);
+
+/**
+ * drm_dev_fini - Finalize a dead DRM device
+ * @dev: DRM device
+ *
+ * Finalize a dead DRM device. This is the converse to drm_dev_init() and
+ * frees up all data allocated by it. All driver private data should be
+ * finalized first. Note that this function does not free the @dev, that is
+ * left to the caller.
+ *
+ * The ref-count of @dev must be zero, and drm_dev_fini() should only be called
+ * from a &drm_driver.release callback.
+ */
+void drm_dev_fini(struct drm_device *dev)
+{
+	drm_vblank_cleanup(dev);
+
+	if (drm_core_check_feature(dev, DRIVER_GEM))
+		drm_gem_destroy(dev);
+
+	drm_legacy_ctxbitmap_cleanup(dev);
+	drm_ht_remove(&dev->map_hash);
+	drm_fs_inode_free(dev->anon_inode);
+
+	drm_minor_free(dev, DRM_MINOR_PRIMARY);
+	drm_minor_free(dev, DRM_MINOR_RENDER);
+
+	put_device(dev->dev);
+
+	mutex_destroy(&dev->master_mutex);
+	mutex_destroy(&dev->ctxlist_mutex);
+	mutex_destroy(&dev->clientlist_mutex);
+	mutex_destroy(&dev->filelist_mutex);
+	mutex_destroy(&dev->struct_mutex);
+	kfree(dev->unique);
+}
+EXPORT_SYMBOL(drm_dev_fini);
+
+/**
+ * drm_dev_alloc - Allocate new DRM device
+ * @driver: DRM driver to allocate device for
+ * @parent: Parent device object
+ *
+ * Allocate and initialize a new DRM device. No device registration is done.
+ * Call drm_dev_register() to advertice the device to user space and register it
+ * with other core subsystems. This should be done last in the device
+ * initialization sequence to make sure userspace can't access an inconsistent
+ * state.
+ *
+ * The initial ref-count of the object is 1. Use drm_dev_get() and
+ * drm_dev_put() to take and drop further ref-counts.
+ *
+ * Note that for purely virtual devices @parent can be NULL.
+ *
+ * Drivers that wish to subclass or embed &struct drm_device into their
+ * own struct should look at using drm_dev_init() instead.
+ *
+ * RETURNS:
+ * Pointer to new DRM device, or ERR_PTR on failure.
+ */
+struct drm_device *drm_dev_alloc(struct drm_driver *driver,
+				 struct device *parent)
+{
+	struct drm_device *dev;
+	int ret;
+
+	dev = kzalloc(sizeof(*dev), GFP_KERNEL);
+	if (!dev)
+		return ERR_PTR(-ENOMEM);
+
+	ret = drm_dev_init(dev, driver, parent);
+	if (ret) {
+		kfree(dev);
+		return ERR_PTR(ret);
+	}
+
+	return dev;
+}
+EXPORT_SYMBOL(drm_dev_alloc);
+
+static void drm_dev_release(struct kref *ref)
+{
+	struct drm_device *dev = container_of(ref, struct drm_device, ref);
+
+	if (dev->driver->release) {
+		dev->driver->release(dev);
+	} else {
+		drm_dev_fini(dev);
+		kfree(dev);
+	}
+}
+
+/**
+ * drm_dev_get - Take reference of a DRM device
+ * @dev: device to take reference of or NULL
+ *
+ * This increases the ref-count of @dev by one. You *must* already own a
+ * reference when calling this. Use drm_dev_put() to drop this reference
+ * again.
+ *
+ * This function never fails. However, this function does not provide *any*
+ * guarantee whether the device is alive or running. It only provides a
+ * reference to the object and the memory associated with it.
+ */
+void drm_dev_get(struct drm_device *dev)
+{
+	if (dev)
+		kref_get(&dev->ref);
+}
+EXPORT_SYMBOL(drm_dev_get);
+
+/**
+ * drm_dev_put - Drop reference of a DRM device
+ * @dev: device to drop reference of or NULL
+ *
+ * This decreases the ref-count of @dev by one. The device is destroyed if the
+ * ref-count drops to zero.
+ */
+void drm_dev_put(struct drm_device *dev)
+{
+	if (dev)
+		kref_put(&dev->ref, drm_dev_release);
+}
+EXPORT_SYMBOL(drm_dev_put);
+
+/**
+ * drm_dev_unref - Drop reference of a DRM device
+ * @dev: device to drop reference of or NULL
+ *
+ * This is a compatibility alias for drm_dev_put() and should not be used by new
+ * code.
+ */
+void drm_dev_unref(struct drm_device *dev)
+{
+	drm_dev_put(dev);
+}
+EXPORT_SYMBOL(drm_dev_unref);
+
+static int create_compat_control_link(struct drm_device *dev)
+{
+	struct drm_minor *minor;
+	char *name;
+	int ret;
+
+	if (!drm_core_check_feature(dev, DRIVER_MODESET))
+		return 0;
+
+	minor = *drm_minor_get_slot(dev, DRM_MINOR_PRIMARY);
+	if (!minor)
+		return 0;
+
+	/*
+	 * Some existing userspace out there uses the existing of the controlD*
+	 * sysfs files to figure out whether it's a modeset driver. It only does
+	 * readdir, hence a symlink is sufficient (and the least confusing
+	 * option). Otherwise controlD* is entirely unused.
+	 *
+	 * Old controlD chardev have been allocated in the range
+	 * 64-127.
+	 */
+	name = kasprintf(GFP_KERNEL, "controlD%d", minor->index + 64);
+	if (!name)
+		return -ENOMEM;
+
+	ret = sysfs_create_link(minor->kdev->kobj.parent,
+				&minor->kdev->kobj,
+				name);
+
+	kfree(name);
+
+	return ret;
+}
+
+static void remove_compat_control_link(struct drm_device *dev)
+{
+	struct drm_minor *minor;
+	char *name;
+
+	if (!drm_core_check_feature(dev, DRIVER_MODESET))
+		return;
+
+	minor = *drm_minor_get_slot(dev, DRM_MINOR_PRIMARY);
+	if (!minor)
+		return;
+
+	name = kasprintf(GFP_KERNEL, "controlD%d", minor->index + 64);
+	if (!name)
+		return;
+
+	sysfs_remove_link(minor->kdev->kobj.parent, name);
+
+	kfree(name);
+}
+
+/**
+ * drm_dev_register - Register DRM device
+ * @dev: Device to register
+ * @flags: Flags passed to the driver's .load() function
+ *
+ * Register the DRM device @dev with the system, advertise device to user-space
+ * and start normal device operation. @dev must be allocated via drm_dev_alloc()
+ * previously.
+ *
+ * Never call this twice on any device!
+ *
+ * NOTE: To ensure backward compatibility with existing drivers method this
+ * function calls the &drm_driver.load method after registering the device
+ * nodes, creating race conditions. Usage of the &drm_driver.load methods is
+ * therefore deprecated, drivers must perform all initialization before calling
+ * drm_dev_register().
+ *
+ * RETURNS:
+ * 0 on success, negative error code on failure.
+ */
+int drm_dev_register(struct drm_device *dev, unsigned long flags)
+{
+	struct drm_driver *driver = dev->driver;
+	int ret;
+
+	mutex_lock(&drm_global_mutex);
+
+	ret = drm_minor_register(dev, DRM_MINOR_RENDER);
+	if (ret)
+		goto err_minors;
+
+	ret = drm_minor_register(dev, DRM_MINOR_PRIMARY);
+	if (ret)
+		goto err_minors;
+
+	ret = create_compat_control_link(dev);
+	if (ret)
+		goto err_minors;
+
+	dev->registered = true;
+
+	if (dev->driver->load) {
+		ret = dev->driver->load(dev, flags);
+		if (ret)
+			goto err_minors;
+	}
+
+	if (drm_core_check_feature(dev, DRIVER_MODESET))
+		drm_modeset_register_all(dev);
+
+	ret = 0;
+
+	DRM_INFO("Initialized %s %d.%d.%d %s for %s on minor %d\n",
+		 driver->name, driver->major, driver->minor,
+		 driver->patchlevel, driver->date,
+		 dev->dev ? dev_name(dev->dev) : "virtual device",
+		 dev->primary->index);
+
+	goto out_unlock;
+
+err_minors:
+	remove_compat_control_link(dev);
+	drm_minor_unregister(dev, DRM_MINOR_PRIMARY);
+	drm_minor_unregister(dev, DRM_MINOR_RENDER);
+out_unlock:
+	mutex_unlock(&drm_global_mutex);
+	return ret;
+}
+EXPORT_SYMBOL(drm_dev_register);
+
+/**
+ * drm_dev_unregister - Unregister DRM device
+ * @dev: Device to unregister
+ *
+ * Unregister the DRM device from the system. This does the reverse of
+ * drm_dev_register() but does not deallocate the device. The caller must call
+ * drm_dev_put() to drop their final reference.
+ *
+ * A special form of unregistering for hotpluggable devices is drm_dev_unplug(),
+ * which can be called while there are still open users of @dev.
+ *
+ * This should be called first in the device teardown code to make sure
+ * userspace can't access the device instance any more.
+ */
+void drm_dev_unregister(struct drm_device *dev)
+{
+	struct drm_map_list *r_list, *list_temp;
+
+	if (drm_core_check_feature(dev, DRIVER_LEGACY))
+		drm_lastclose(dev);
+
+	dev->registered = false;
+
+	drm_client_dev_unregister(dev);
+
+	if (drm_core_check_feature(dev, DRIVER_MODESET))
+		drm_modeset_unregister_all(dev);
+
+	if (dev->driver->unload)
+		dev->driver->unload(dev);
+
+	if (dev->agp)
+		drm_pci_agp_destroy(dev);
+
+	list_for_each_entry_safe(r_list, list_temp, &dev->maplist, head)
+		drm_legacy_rmmap(dev, r_list->map);
+
+	remove_compat_control_link(dev);
+	drm_minor_unregister(dev, DRM_MINOR_PRIMARY);
+	drm_minor_unregister(dev, DRM_MINOR_RENDER);
+}
+EXPORT_SYMBOL(drm_dev_unregister);
+
+/**
+ * drm_dev_set_unique - Set the unique name of a DRM device
+ * @dev: device of which to set the unique name
+ * @name: unique name
+ *
+ * Sets the unique name of a DRM device using the specified string. Drivers
+ * can use this at driver probe time if the unique name of the devices they
+ * drive is static.
+ *
+ * Return: 0 on success or a negative error code on failure.
+ */
+int drm_dev_set_unique(struct drm_device *dev, const char *name)
+{
+	kfree(dev->unique);
+	dev->unique = kstrdup(name, GFP_KERNEL);
+
+	return dev->unique ? 0 : -ENOMEM;
+}
+EXPORT_SYMBOL(drm_dev_set_unique);
+
+/*
+ * DRM Core
+ * The DRM core module initializes all global DRM objects and makes them
+ * available to drivers. Once setup, drivers can probe their respective
+ * devices.
+ * Currently, core management includes:
+ *  - The "DRM-Global" key/value database
+ *  - Global ID management for connectors
+ *  - DRM major number allocation
+ *  - DRM minor management
+ *  - DRM sysfs class
+ *  - DRM debugfs root
+ *
+ * Furthermore, the DRM core provides dynamic char-dev lookups. For each
+ * interface registered on a DRM device, you can request minor numbers from DRM
+ * core. DRM core takes care of major-number management and char-dev
+ * registration. A stub ->open() callback forwards any open() requests to the
+ * registered minor.
+ */
+
+static int drm_stub_open(struct inode *inode, struct file *filp)
+{
+	const struct file_operations *new_fops;
+	struct drm_minor *minor;
+	int err;
+
+	DRM_DEBUG("\n");
+
+	mutex_lock(&drm_global_mutex);
+	minor = drm_minor_acquire(iminor(inode));
+	if (IS_ERR(minor)) {
+		err = PTR_ERR(minor);
+		goto out_unlock;
+	}
+
+	new_fops = fops_get(minor->dev->driver->fops);
+	if (!new_fops) {
+		err = -ENODEV;
+		goto out_release;
+	}
+
+	replace_fops(filp, new_fops);
+	if (filp->f_op->open)
+		err = filp->f_op->open(inode, filp);
+	else
+		err = 0;
+
+out_release:
+	drm_minor_release(minor);
+out_unlock:
+	mutex_unlock(&drm_global_mutex);
+	return err;
+}
+
+static const struct file_operations drm_stub_fops = {
+	.owner = THIS_MODULE,
+	.open = drm_stub_open,
+	.llseek = noop_llseek,
+};
+
+static void drm_core_exit(void)
+{
+	unregister_chrdev(DRM_MAJOR, "drm");
+	debugfs_remove(drm_debugfs_root);
+	drm_sysfs_destroy();
+	idr_destroy(&drm_minors_idr);
+	drm_connector_ida_destroy();
+	drm_global_release();
+}
+
+static int __init drm_core_init(void)
+{
+	int ret;
+
+	drm_global_init();
+	drm_connector_ida_init();
+	idr_init(&drm_minors_idr);
+
+	ret = drm_sysfs_init();
+	if (ret < 0) {
+		DRM_ERROR("Cannot create DRM class: %d\n", ret);
+		goto error;
+	}
+
+	drm_debugfs_root = debugfs_create_dir("dri", NULL);
+	if (!drm_debugfs_root) {
+		ret = -ENOMEM;
+		DRM_ERROR("Cannot create debugfs-root: %d\n", ret);
+		goto error;
+	}
+
+	ret = register_chrdev(DRM_MAJOR, "drm", &drm_stub_fops);
+	if (ret < 0)
+		goto error;
+
+	drm_core_init_complete = true;
+
+	DRM_DEBUG("Initialized\n");
+	return 0;
+
+error:
+	drm_core_exit();
+	return ret;
+}
+
+module_init(drm_core_init);
+module_exit(drm_core_exit);