drivers/gpu/drm/drm_debugfs.c - third_party/linux - Git at Google

 /*
  * Created: Sun Dec 21 13:08:50 2008 by bgamari@gmail.com
  *
  * Copyright 2008 Ben Gamari <bgamari@gmail.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
  * VA LINUX SYSTEMS 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/seq_file.h>
 #include <linux/slab.h>
 #include <linux/export.h>

 #include <drm/drm_debugfs.h>
 #include <drm/drm_edid.h>
 #include <drm/drm_atomic.h>
 #include <drm/drmP.h>

 #include "drm_internal.h"
 #include "drm_crtc_internal.h"

 #if defined(CONFIG_DEBUG_FS)

 /***************************************************
  * Initialization, etc.
  **************************************************/

 static const struct drm_info_list drm_debugfs_list[] = {
 	{"name", drm_name_info, 0},
 	{"clients", drm_clients_info, 0},
 	{"gem_names", drm_gem_name_info, DRIVER_GEM},
 };
 #define DRM_DEBUGFS_ENTRIES ARRAY_SIZE(drm_debugfs_list)


 static int drm_debugfs_open(struct inode *inode, struct file *file)
 {
 	struct drm_info_node *node = inode->i_private;

 	return single_open(file, node->info_ent->show, node);
 }


 static const struct file_operations drm_debugfs_fops = {
 	.owner = THIS_MODULE,
 	.open = drm_debugfs_open,
 	.read = seq_read,
 	.llseek = seq_lseek,
 	.release = single_release,
 };


 /**
  * drm_debugfs_create_files - Initialize a given set of debugfs files for DRM
  * 			minor
  * @files: The array of files to create
  * @count: The number of files given
  * @root: DRI debugfs dir entry.
  * @minor: device minor number
  *
  * Create a given set of debugfs files represented by an array of
  * &struct drm_info_list in the given root directory. These files will be removed
  * automatically on drm_debugfs_cleanup().
  */
 int drm_debugfs_create_files(const struct drm_info_list *files, int count,
 			     struct dentry *root, struct drm_minor *minor)
 {
 	struct drm_device *dev = minor->dev;
 	struct dentry *ent;
 	struct drm_info_node *tmp;
 	int i, ret;

 	for (i = 0; i < count; i++) {
 		u32 features = files[i].driver_features;

 		if (features != 0 &&
 		    (dev->driver->driver_features & features) != features)
 			continue;

 		tmp = kmalloc(sizeof(struct drm_info_node), GFP_KERNEL);
 		if (tmp == NULL) {
 			ret = -1;
 			goto fail;
 		}
 		ent = debugfs_create_file(files[i].name, S_IFREG | S_IRUGO,
 					  root, tmp, &drm_debugfs_fops);
 		if (!ent) {
 			DRM_ERROR("Cannot create /sys/kernel/debug/dri/%pd/%s\n",
 				  root, files[i].name);
 			kfree(tmp);
 			ret = -1;
 			goto fail;
 		}

 		tmp->minor = minor;
 		tmp->dent = ent;
 		tmp->info_ent = &files[i];

 		mutex_lock(&minor->debugfs_lock);
 		list_add(&tmp->list, &minor->debugfs_list);
 		mutex_unlock(&minor->debugfs_lock);
 	}
 	return 0;

 fail:
 	drm_debugfs_remove_files(files, count, minor);
 	return ret;
 }
 EXPORT_SYMBOL(drm_debugfs_create_files);

 int drm_debugfs_init(struct drm_minor *minor, int minor_id,
 		     struct dentry *root)
 {
 	struct drm_device *dev = minor->dev;
 	char name[64];
 	int ret;

 	INIT_LIST_HEAD(&minor->debugfs_list);
 	mutex_init(&minor->debugfs_lock);
 	sprintf(name, "%d", minor_id);
 	minor->debugfs_root = debugfs_create_dir(name, root);
 	if (!minor->debugfs_root) {
 		DRM_ERROR("Cannot create /sys/kernel/debug/dri/%s\n", name);
 		return -1;
 	}

 	ret = drm_debugfs_create_files(drm_debugfs_list, DRM_DEBUGFS_ENTRIES,
 				       minor->debugfs_root, minor);
 	if (ret) {
 		debugfs_remove(minor->debugfs_root);
 		minor->debugfs_root = NULL;
 		DRM_ERROR("Failed to create core drm debugfs files\n");
 		return ret;
 	}

 	if (drm_core_check_feature(dev, DRIVER_ATOMIC)) {
 		ret = drm_atomic_debugfs_init(minor);
 		if (ret) {
 			DRM_ERROR("Failed to create atomic debugfs files\n");
 			return ret;
 		}
 	}

 	if (drm_core_check_feature(dev, DRIVER_MODESET)) {
 		ret = drm_framebuffer_debugfs_init(minor);
 		if (ret) {
 			DRM_ERROR("Failed to create framebuffer debugfs file\n");
 			return ret;
 		}
 	}

 	if (dev->driver->debugfs_init) {
 		ret = dev->driver->debugfs_init(minor);
 		if (ret) {
 			DRM_ERROR("DRM: Driver failed to initialize "
 				  "/sys/kernel/debug/dri.\n");
 			return ret;
 		}
 	}
 	return 0;
 }


 int drm_debugfs_remove_files(const struct drm_info_list *files, int count,
 			     struct drm_minor *minor)
 {
 	struct list_head *pos, *q;
 	struct drm_info_node *tmp;
 	int i;

 	mutex_lock(&minor->debugfs_lock);
 	for (i = 0; i < count; i++) {
 		list_for_each_safe(pos, q, &minor->debugfs_list) {
 			tmp = list_entry(pos, struct drm_info_node, list);
 			if (tmp->info_ent == &files[i]) {
 				debugfs_remove(tmp->dent);
 				list_del(pos);
 				kfree(tmp);
 			}
 		}
 	}
 	mutex_unlock(&minor->debugfs_lock);
 	return 0;
 }
 EXPORT_SYMBOL(drm_debugfs_remove_files);

 static void drm_debugfs_remove_all_files(struct drm_minor *minor)
 {
 	struct drm_info_node *node, *tmp;

 	mutex_lock(&minor->debugfs_lock);
 	list_for_each_entry_safe(node, tmp, &minor->debugfs_list, list) {
 		debugfs_remove(node->dent);
 		list_del(&node->list);
 		kfree(node);
 	}
 	mutex_unlock(&minor->debugfs_lock);
 }

 int drm_debugfs_cleanup(struct drm_minor *minor)
 {
 	if (!minor->debugfs_root)
 		return 0;

 	drm_debugfs_remove_all_files(minor);

 	debugfs_remove_recursive(minor->debugfs_root);
 	minor->debugfs_root = NULL;

 	return 0;
 }

 static int connector_show(struct seq_file *m, void *data)
 {
 	struct drm_connector *connector = m->private;

 	seq_printf(m, "%s\n", drm_get_connector_force_name(connector->force));

 	return 0;
 }

 static int connector_open(struct inode *inode, struct file *file)
 {
 	struct drm_connector *dev = inode->i_private;

 	return single_open(file, connector_show, dev);
 }

 static ssize_t connector_write(struct file *file, const char __user *ubuf,
 			       size_t len, loff_t *offp)
 {
 	struct seq_file *m = file->private_data;
 	struct drm_connector *connector = m->private;
 	char buf[12];

 	if (len > sizeof(buf) - 1)
 		return -EINVAL;

 	if (copy_from_user(buf, ubuf, len))
 		return -EFAULT;

 	buf[len] = '\0';

 	if (!strcmp(buf, "on"))
 		connector->force = DRM_FORCE_ON;
 	else if (!strcmp(buf, "digital"))
 		connector->force = DRM_FORCE_ON_DIGITAL;
 	else if (!strcmp(buf, "off"))
 		connector->force = DRM_FORCE_OFF;
 	else if (!strcmp(buf, "unspecified"))
 		connector->force = DRM_FORCE_UNSPECIFIED;
 	else
 		return -EINVAL;

 	return len;
 }

 static int edid_show(struct seq_file *m, void *data)
 {
 	struct drm_connector *connector = m->private;
 	struct drm_property_blob *edid = connector->edid_blob_ptr;

 	if (connector->override_edid && edid)
 		seq_write(m, edid->data, edid->length);

 	return 0;
 }

 static int edid_open(struct inode *inode, struct file *file)
 {
 	struct drm_connector *dev = inode->i_private;

 	return single_open(file, edid_show, dev);
 }

 static ssize_t edid_write(struct file *file, const char __user *ubuf,
 			  size_t len, loff_t *offp)
 {
 	struct seq_file *m = file->private_data;
 	struct drm_connector *connector = m->private;
 	char *buf;
 	struct edid *edid;
 	int ret;

 	buf = memdup_user(ubuf, len);
 	if (IS_ERR(buf))
 		return PTR_ERR(buf);

 	edid = (struct edid *) buf;

 	if (len == 5 && !strncmp(buf, "reset", 5)) {
 		connector->override_edid = false;
 		ret = drm_mode_connector_update_edid_property(connector, NULL);
 	} else if (len < EDID_LENGTH ||
 		   EDID_LENGTH * (1 + edid->extensions) > len)
 		ret = -EINVAL;
 	else {
 		connector->override_edid = false;
 		ret = drm_mode_connector_update_edid_property(connector, edid);
 		if (!ret)
 			connector->override_edid = true;
 	}

 	kfree(buf);

 	return (ret) ? ret : len;
 }

 static const struct file_operations drm_edid_fops = {
 	.owner = THIS_MODULE,
 	.open = edid_open,
 	.read = seq_read,
 	.llseek = seq_lseek,
 	.release = single_release,
 	.write = edid_write
 };


 static const struct file_operations drm_connector_fops = {
 	.owner = THIS_MODULE,
 	.open = connector_open,
 	.read = seq_read,
 	.llseek = seq_lseek,
 	.release = single_release,
 	.write = connector_write
 };

 int drm_debugfs_connector_add(struct drm_connector *connector)
 {
 	struct drm_minor *minor = connector->dev->primary;
 	struct dentry *root, *ent;

 	if (!minor->debugfs_root)
 		return -1;

 	root = debugfs_create_dir(connector->name, minor->debugfs_root);
 	if (!root)
 		return -ENOMEM;

 	connector->debugfs_entry = root;

 	/* force */
 	ent = debugfs_create_file("force", S_IRUGO | S_IWUSR, root, connector,
 				  &drm_connector_fops);
 	if (!ent)
 		goto error;

 	/* edid */
 	ent = debugfs_create_file("edid_override", S_IRUGO | S_IWUSR, root,
 				  connector, &drm_edid_fops);
 	if (!ent)
 		goto error;

 	return 0;

 error:
 	debugfs_remove_recursive(connector->debugfs_entry);
 	connector->debugfs_entry = NULL;
 	return -ENOMEM;
 }

 void drm_debugfs_connector_remove(struct drm_connector *connector)
 {
 	if (!connector->debugfs_entry)
 		return;

 	debugfs_remove_recursive(connector->debugfs_entry);

 	connector->debugfs_entry = NULL;
 }

 int drm_debugfs_crtc_add(struct drm_crtc *crtc)
 {
 	struct drm_minor *minor = crtc->dev->primary;
 	struct dentry *root;
 	char *name;

 	name = kasprintf(GFP_KERNEL, "crtc-%d", crtc->index);
 	if (!name)
 		return -ENOMEM;

 	root = debugfs_create_dir(name, minor->debugfs_root);
 	kfree(name);
 	if (!root)
 		return -ENOMEM;

 	crtc->debugfs_entry = root;

 	if (drm_debugfs_crtc_crc_add(crtc))
 		goto error;

 	return 0;

 error:
 	drm_debugfs_crtc_remove(crtc);
 	return -ENOMEM;
 }

 void drm_debugfs_crtc_remove(struct drm_crtc *crtc)
 {
 	debugfs_remove_recursive(crtc->debugfs_entry);
 	crtc->debugfs_entry = NULL;
 }

 #endif /* CONFIG_DEBUG_FS */
	/*
	* Created: Sun Dec 21 13:08:50 2008 by bgamari@gmail.com
	*
	* Copyright 2008 Ben Gamari <bgamari@gmail.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
	* VA LINUX SYSTEMS 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/seq_file.h>
	#include <linux/slab.h>
	#include <linux/export.h>

	#include <drm/drm_debugfs.h>
	#include <drm/drm_edid.h>
	#include <drm/drm_atomic.h>
	#include <drm/drmP.h>

	#include "drm_internal.h"
	#include "drm_crtc_internal.h"

	#if defined(CONFIG_DEBUG_FS)

	/***************************************************
	* Initialization, etc.
	**************************************************/

	static const struct drm_info_list drm_debugfs_list[] = {
	{"name", drm_name_info, 0},
	{"clients", drm_clients_info, 0},
	{"gem_names", drm_gem_name_info, DRIVER_GEM},
	};
	#define DRM_DEBUGFS_ENTRIES ARRAY_SIZE(drm_debugfs_list)


	static int drm_debugfs_open(struct inode inode, struct file file)
	{
	struct drm_info_node *node = inode->i_private;

	return single_open(file, node->info_ent->show, node);
	}


	static const struct file_operations drm_debugfs_fops = {
	.owner = THIS_MODULE,
	.open = drm_debugfs_open,
	.read = seq_read,
	.llseek = seq_lseek,
	.release = single_release,
	};


	/**
	* drm_debugfs_create_files - Initialize a given set of debugfs files for DRM
	* minor
	* @files: The array of files to create
	* @count: The number of files given
	* @root: DRI debugfs dir entry.
	* @minor: device minor number
	*
	* Create a given set of debugfs files represented by an array of
	* &struct drm_info_list in the given root directory. These files will be removed
	* automatically on drm_debugfs_cleanup().
	*/
	int drm_debugfs_create_files(const struct drm_info_list *files, int count,
	struct dentry root, struct drm_minor minor)
	{
	struct drm_device *dev = minor->dev;
	struct dentry *ent;
	struct drm_info_node *tmp;
	int i, ret;

	for (i = 0; i < count; i++) {
	u32 features = files[i].driver_features;

	if (features != 0 &&
	(dev->driver->driver_features & features) != features)
	continue;

	tmp = kmalloc(sizeof(struct drm_info_node), GFP_KERNEL);
	if (tmp == NULL) {
	ret = -1;
	goto fail;
	}
	ent = debugfs_create_file(files[i].name, S_IFREG \| S_IRUGO,
	root, tmp, &drm_debugfs_fops);
	if (!ent) {
	DRM_ERROR("Cannot create /sys/kernel/debug/dri/%pd/%s\n",
	root, files[i].name);
	kfree(tmp);
	ret = -1;
	goto fail;
	}

	tmp->minor = minor;
	tmp->dent = ent;
	tmp->info_ent = &files[i];

	mutex_lock(&minor->debugfs_lock);
	list_add(&tmp->list, &minor->debugfs_list);
	mutex_unlock(&minor->debugfs_lock);
	}
	return 0;

	fail:
	drm_debugfs_remove_files(files, count, minor);
	return ret;
	}
	EXPORT_SYMBOL(drm_debugfs_create_files);

	int drm_debugfs_init(struct drm_minor *minor, int minor_id,
	struct dentry *root)
	{
	struct drm_device *dev = minor->dev;
	char name[64];
	int ret;

	INIT_LIST_HEAD(&minor->debugfs_list);
	mutex_init(&minor->debugfs_lock);
	sprintf(name, "%d", minor_id);
	minor->debugfs_root = debugfs_create_dir(name, root);
	if (!minor->debugfs_root) {
	DRM_ERROR("Cannot create /sys/kernel/debug/dri/%s\n", name);
	return -1;
	}

	ret = drm_debugfs_create_files(drm_debugfs_list, DRM_DEBUGFS_ENTRIES,
	minor->debugfs_root, minor);
	if (ret) {
	debugfs_remove(minor->debugfs_root);
	minor->debugfs_root = NULL;
	DRM_ERROR("Failed to create core drm debugfs files\n");
	return ret;
	}

	if (drm_core_check_feature(dev, DRIVER_ATOMIC)) {
	ret = drm_atomic_debugfs_init(minor);
	if (ret) {
	DRM_ERROR("Failed to create atomic debugfs files\n");
	return ret;
	}
	}

	if (drm_core_check_feature(dev, DRIVER_MODESET)) {
	ret = drm_framebuffer_debugfs_init(minor);
	if (ret) {
	DRM_ERROR("Failed to create framebuffer debugfs file\n");
	return ret;
	}
	}

	if (dev->driver->debugfs_init) {
	ret = dev->driver->debugfs_init(minor);
	if (ret) {
	DRM_ERROR("DRM: Driver failed to initialize "
	"/sys/kernel/debug/dri.\n");
	return ret;
	}
	}
	return 0;
	}


	int drm_debugfs_remove_files(const struct drm_info_list *files, int count,
	struct drm_minor *minor)
	{
	struct list_head pos, q;
	struct drm_info_node *tmp;
	int i;

	mutex_lock(&minor->debugfs_lock);
	for (i = 0; i < count; i++) {
	list_for_each_safe(pos, q, &minor->debugfs_list) {
	tmp = list_entry(pos, struct drm_info_node, list);
	if (tmp->info_ent == &files[i]) {
	debugfs_remove(tmp->dent);
	list_del(pos);
	kfree(tmp);
	}
	}
	}
	mutex_unlock(&minor->debugfs_lock);
	return 0;
	}
	EXPORT_SYMBOL(drm_debugfs_remove_files);

	static void drm_debugfs_remove_all_files(struct drm_minor *minor)
	{
	struct drm_info_node node, tmp;

	mutex_lock(&minor->debugfs_lock);
	list_for_each_entry_safe(node, tmp, &minor->debugfs_list, list) {
	debugfs_remove(node->dent);
	list_del(&node->list);
	kfree(node);
	}
	mutex_unlock(&minor->debugfs_lock);
	}

	int drm_debugfs_cleanup(struct drm_minor *minor)
	{
	if (!minor->debugfs_root)
	return 0;

	drm_debugfs_remove_all_files(minor);

	debugfs_remove_recursive(minor->debugfs_root);
	minor->debugfs_root = NULL;

	return 0;
	}

	static int connector_show(struct seq_file m, void data)
	{
	struct drm_connector *connector = m->private;

	seq_printf(m, "%s\n", drm_get_connector_force_name(connector->force));

	return 0;
	}

	static int connector_open(struct inode inode, struct file file)
	{
	struct drm_connector *dev = inode->i_private;

	return single_open(file, connector_show, dev);
	}

	static ssize_t connector_write(struct file file, const char __user ubuf,
	size_t len, loff_t *offp)
	{
	struct seq_file *m = file->private_data;
	struct drm_connector *connector = m->private;
	char buf[12];

	if (len > sizeof(buf) - 1)
	return -EINVAL;

	if (copy_from_user(buf, ubuf, len))
	return -EFAULT;

	buf[len] = '\0';

	if (!strcmp(buf, "on"))
	connector->force = DRM_FORCE_ON;
	else if (!strcmp(buf, "digital"))
	connector->force = DRM_FORCE_ON_DIGITAL;
	else if (!strcmp(buf, "off"))
	connector->force = DRM_FORCE_OFF;
	else if (!strcmp(buf, "unspecified"))
	connector->force = DRM_FORCE_UNSPECIFIED;
	else
	return -EINVAL;

	return len;
	}

	static int edid_show(struct seq_file m, void data)
	{
	struct drm_connector *connector = m->private;
	struct drm_property_blob *edid = connector->edid_blob_ptr;

	if (connector->override_edid && edid)
	seq_write(m, edid->data, edid->length);

	return 0;
	}

	static int edid_open(struct inode inode, struct file file)
	{
	struct drm_connector *dev = inode->i_private;

	return single_open(file, edid_show, dev);
	}

	static ssize_t edid_write(struct file file, const char __user ubuf,
	size_t len, loff_t *offp)
	{
	struct seq_file *m = file->private_data;
	struct drm_connector *connector = m->private;
	char *buf;
	struct edid *edid;
	int ret;

	buf = memdup_user(ubuf, len);
	if (IS_ERR(buf))
	return PTR_ERR(buf);

	edid = (struct edid *) buf;

	if (len == 5 && !strncmp(buf, "reset", 5)) {
	connector->override_edid = false;
	ret = drm_mode_connector_update_edid_property(connector, NULL);
	} else if (len < EDID_LENGTH \|\|
	EDID_LENGTH * (1 + edid->extensions) > len)
	ret = -EINVAL;
	else {
	connector->override_edid = false;
	ret = drm_mode_connector_update_edid_property(connector, edid);
	if (!ret)
	connector->override_edid = true;
	}

	kfree(buf);

	return (ret) ? ret : len;
	}

	static const struct file_operations drm_edid_fops = {
	.owner = THIS_MODULE,
	.open = edid_open,
	.read = seq_read,
	.llseek = seq_lseek,
	.release = single_release,
	.write = edid_write
	};


	static const struct file_operations drm_connector_fops = {
	.owner = THIS_MODULE,
	.open = connector_open,
	.read = seq_read,
	.llseek = seq_lseek,
	.release = single_release,
	.write = connector_write
	};

	int drm_debugfs_connector_add(struct drm_connector *connector)
	{
	struct drm_minor *minor = connector->dev->primary;
	struct dentry root, ent;

	if (!minor->debugfs_root)
	return -1;

	root = debugfs_create_dir(connector->name, minor->debugfs_root);
	if (!root)
	return -ENOMEM;

	connector->debugfs_entry = root;

	/* force */
	ent = debugfs_create_file("force", S_IRUGO \| S_IWUSR, root, connector,
	&drm_connector_fops);
	if (!ent)
	goto error;

	/* edid */
	ent = debugfs_create_file("edid_override", S_IRUGO \| S_IWUSR, root,
	connector, &drm_edid_fops);
	if (!ent)
	goto error;

	return 0;

	error:
	debugfs_remove_recursive(connector->debugfs_entry);
	connector->debugfs_entry = NULL;
	return -ENOMEM;
	}

	void drm_debugfs_connector_remove(struct drm_connector *connector)
	{
	if (!connector->debugfs_entry)
	return;

	debugfs_remove_recursive(connector->debugfs_entry);

	connector->debugfs_entry = NULL;
	}

	int drm_debugfs_crtc_add(struct drm_crtc *crtc)
	{
	struct drm_minor *minor = crtc->dev->primary;
	struct dentry *root;
	char *name;

	name = kasprintf(GFP_KERNEL, "crtc-%d", crtc->index);
	if (!name)
	return -ENOMEM;

	root = debugfs_create_dir(name, minor->debugfs_root);
	kfree(name);
	if (!root)
	return -ENOMEM;

	crtc->debugfs_entry = root;

	if (drm_debugfs_crtc_crc_add(crtc))
	goto error;

	return 0;

	error:
	drm_debugfs_crtc_remove(crtc);
	return -ENOMEM;
	}

	void drm_debugfs_crtc_remove(struct drm_crtc *crtc)
	{
	debugfs_remove_recursive(crtc->debugfs_entry);
	crtc->debugfs_entry = NULL;
	}

	#endif /* CONFIG_DEBUG_FS */