[mirror_ubuntu-artful-kernel.git] / drivers / gpu / drm / drm_lock.c

/**
 * \file drm_lock.c
 * IOCTLs for locking
 *
 * \author Rickard E. (Rik) Faith <faith@valinux.com>
 * \author Gareth Hughes <gareth@valinux.com>
 */

/*
 * Created: Tue Feb  2 08:37:54 1999 by faith@valinux.com
 *
 * Copyright 1999 Precision Insight, Inc., Cedar Park, Texas.
 * Copyright 2000 VA Linux Systems, Inc., Sunnyvale, California.
 * All Rights Reserved.
 *
 * 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/export.h>
#include <drm/drmP.h>
#include "drm_legacy.h"
#include "drm_internal.h"

static int drm_lock_take(struct drm_lock_data *lock_data, unsigned int context);

/**
 * Take the heavyweight lock.
 *
 * \param lock lock pointer.
 * \param context locking context.
 * \return one if the lock is held, or zero otherwise.
 *
 * Attempt to mark the lock as held by the given context, via the \p cmpxchg instruction.
 */
static
int drm_lock_take(struct drm_lock_data *lock_data,
		  unsigned int context)
{
	unsigned int old, new, prev;
	volatile unsigned int *lock = &lock_data->hw_lock->lock;

	spin_lock_bh(&lock_data->spinlock);
	do {
		old = *lock;
		if (old & _DRM_LOCK_HELD)
			new = old | _DRM_LOCK_CONT;
		else {
			new = context | _DRM_LOCK_HELD |
				((lock_data->user_waiters + lock_data->kernel_waiters > 1) ?
				 _DRM_LOCK_CONT : 0);
		}
		prev = cmpxchg(lock, old, new);
	} while (prev != old);
	spin_unlock_bh(&lock_data->spinlock);

	if (_DRM_LOCKING_CONTEXT(old) == context) {
		if (old & _DRM_LOCK_HELD) {
			if (context != DRM_KERNEL_CONTEXT) {
				DRM_ERROR("%d holds heavyweight lock\n",
					  context);
			}
			return 0;
		}
	}

	if ((_DRM_LOCKING_CONTEXT(new)) == context && (new & _DRM_LOCK_HELD)) {
		/* Have lock */
		return 1;
	}
	return 0;
}

/**
 * This takes a lock forcibly and hands it to context.	Should ONLY be used
 * inside *_unlock to give lock to kernel before calling *_dma_schedule.
 *
 * \param dev DRM device.
 * \param lock lock pointer.
 * \param context locking context.
 * \return always one.
 *
 * Resets the lock file pointer.
 * Marks the lock as held by the given context, via the \p cmpxchg instruction.
 */
static int drm_lock_transfer(struct drm_lock_data *lock_data,
			     unsigned int context)
{
	unsigned int old, new, prev;
	volatile unsigned int *lock = &lock_data->hw_lock->lock;

	lock_data->file_priv = NULL;
	do {
		old = *lock;
		new = context | _DRM_LOCK_HELD;
		prev = cmpxchg(lock, old, new);
	} while (prev != old);
	return 1;
}

static int drm_legacy_lock_free(struct drm_lock_data *lock_data,
				unsigned int context)
{
	unsigned int old, new, prev;
	volatile unsigned int *lock = &lock_data->hw_lock->lock;

	spin_lock_bh(&lock_data->spinlock);
	if (lock_data->kernel_waiters != 0) {
		drm_lock_transfer(lock_data, 0);
		lock_data->idle_has_lock = 1;
		spin_unlock_bh(&lock_data->spinlock);
		return 1;
	}
	spin_unlock_bh(&lock_data->spinlock);

	do {
		old = *lock;
		new = _DRM_LOCKING_CONTEXT(old);
		prev = cmpxchg(lock, old, new);
	} while (prev != old);

	if (_DRM_LOCK_IS_HELD(old) && _DRM_LOCKING_CONTEXT(old) != context) {
		DRM_ERROR("%d freed heavyweight lock held by %d\n",
			  context, _DRM_LOCKING_CONTEXT(old));
		return 1;
	}
	wake_up_interruptible(&lock_data->lock_queue);
	return 0;
}

/**
 * Lock ioctl.
 *
 * \param inode device inode.
 * \param file_priv DRM file private.
 * \param cmd command.
 * \param arg user argument, pointing to a drm_lock structure.
 * \return zero on success or negative number on failure.
 *
 * Add the current task to the lock wait queue, and attempt to take to lock.
 */
int drm_legacy_lock(struct drm_device *dev, void *data,
		    struct drm_file *file_priv)
{
	DECLARE_WAITQUEUE(entry, current);
	struct drm_lock *lock = data;
	struct drm_master *master = file_priv->master;
	int ret = 0;

	if (!drm_core_check_feature(dev, DRIVER_LEGACY))
		return -EINVAL;

	++file_priv->lock_count;

	if (lock->context == DRM_KERNEL_CONTEXT) {
		DRM_ERROR("Process %d using kernel context %d\n",
			  task_pid_nr(current), lock->context);
		return -EINVAL;
	}

	DRM_DEBUG("%d (pid %d) requests lock (0x%08x), flags = 0x%08x\n",
		  lock->context, task_pid_nr(current),
		  master->lock.hw_lock ? master->lock.hw_lock->lock : -1,
		  lock->flags);

	add_wait_queue(&master->lock.lock_queue, &entry);
	spin_lock_bh(&master->lock.spinlock);
	master->lock.user_waiters++;
	spin_unlock_bh(&master->lock.spinlock);

	for (;;) {
		__set_current_state(TASK_INTERRUPTIBLE);
		if (!master->lock.hw_lock) {
			/* Device has been unregistered */
			send_sig(SIGTERM, current, 0);
			ret = -EINTR;
			break;
		}
		if (drm_lock_take(&master->lock, lock->context)) {
			master->lock.file_priv = file_priv;
			master->lock.lock_time = jiffies;
			break;	/* Got lock */
		}

		/* Contention */
		mutex_unlock(&drm_global_mutex);
		schedule();
		mutex_lock(&drm_global_mutex);
		if (signal_pending(current)) {
			ret = -EINTR;
			break;
		}
	}
	spin_lock_bh(&master->lock.spinlock);
	master->lock.user_waiters--;
	spin_unlock_bh(&master->lock.spinlock);
	__set_current_state(TASK_RUNNING);
	remove_wait_queue(&master->lock.lock_queue, &entry);

	DRM_DEBUG("%d %s\n", lock->context,
		  ret ? "interrupted" : "has lock");
	if (ret) return ret;

	/* don't set the block all signals on the master process for now 
	 * really probably not the correct answer but lets us debug xkb
 	 * xserver for now */
	if (!drm_is_current_master(file_priv)) {
		dev->sigdata.context = lock->context;
		dev->sigdata.lock = master->lock.hw_lock;
	}

	if (dev->driver->dma_quiescent && (lock->flags & _DRM_LOCK_QUIESCENT))
	{
		if (dev->driver->dma_quiescent(dev)) {
			DRM_DEBUG("%d waiting for DMA quiescent\n",
				  lock->context);
			return -EBUSY;
		}
	}

	return 0;
}

/**
 * Unlock ioctl.
 *
 * \param inode device inode.
 * \param file_priv DRM file private.
 * \param cmd command.
 * \param arg user argument, pointing to a drm_lock structure.
 * \return zero on success or negative number on failure.
 *
 * Transfer and free the lock.
 */
int drm_legacy_unlock(struct drm_device *dev, void *data, struct drm_file *file_priv)
{
	struct drm_lock *lock = data;
	struct drm_master *master = file_priv->master;

	if (!drm_core_check_feature(dev, DRIVER_LEGACY))
		return -EINVAL;

	if (lock->context == DRM_KERNEL_CONTEXT) {
		DRM_ERROR("Process %d using kernel context %d\n",
			  task_pid_nr(current), lock->context);
		return -EINVAL;
	}

	if (drm_legacy_lock_free(&master->lock, lock->context)) {
		/* FIXME: Should really bail out here. */
	}

	return 0;
}

/**
 * This function returns immediately and takes the hw lock
 * with the kernel context if it is free, otherwise it gets the highest priority when and if
 * it is eventually released.
 *
 * This guarantees that the kernel will _eventually_ have the lock _unless_ it is held
 * by a blocked process. (In the latter case an explicit wait for the hardware lock would cause
 * a deadlock, which is why the "idlelock" was invented).
 *
 * This should be sufficient to wait for GPU idle without
 * having to worry about starvation.
 */

void drm_legacy_idlelock_take(struct drm_lock_data *lock_data)
{
	int ret;

	spin_lock_bh(&lock_data->spinlock);
	lock_data->kernel_waiters++;
	if (!lock_data->idle_has_lock) {

		spin_unlock_bh(&lock_data->spinlock);
		ret = drm_lock_take(lock_data, DRM_KERNEL_CONTEXT);
		spin_lock_bh(&lock_data->spinlock);

		if (ret == 1)
			lock_data->idle_has_lock = 1;
	}
	spin_unlock_bh(&lock_data->spinlock);
}
EXPORT_SYMBOL(drm_legacy_idlelock_take);

void drm_legacy_idlelock_release(struct drm_lock_data *lock_data)
{
	unsigned int old, prev;
	volatile unsigned int *lock = &lock_data->hw_lock->lock;

	spin_lock_bh(&lock_data->spinlock);
	if (--lock_data->kernel_waiters == 0) {
		if (lock_data->idle_has_lock) {
			do {
				old = *lock;
				prev = cmpxchg(lock, old, DRM_KERNEL_CONTEXT);
			} while (prev != old);
			wake_up_interruptible(&lock_data->lock_queue);
			lock_data->idle_has_lock = 0;
		}
	}
	spin_unlock_bh(&lock_data->spinlock);
}
EXPORT_SYMBOL(drm_legacy_idlelock_release);

static int drm_legacy_i_have_hw_lock(struct drm_device *dev,
				     struct drm_file *file_priv)
{
	struct drm_master *master = file_priv->master;
	return (file_priv->lock_count && master->lock.hw_lock &&
		_DRM_LOCK_IS_HELD(master->lock.hw_lock->lock) &&
		master->lock.file_priv == file_priv);
}

void drm_legacy_lock_release(struct drm_device *dev, struct file *filp)
{
	struct drm_file *file_priv = filp->private_data;

	/* if the master has gone away we can't do anything with the lock */
	if (!dev->master)
		return;

	if (drm_legacy_i_have_hw_lock(dev, file_priv)) {
		DRM_DEBUG("File %p released, freeing lock for context %d\n",
			  filp, _DRM_LOCKING_CONTEXT(file_priv->master->lock.hw_lock->lock));
		drm_legacy_lock_free(&file_priv->master->lock,
				     _DRM_LOCKING_CONTEXT(file_priv->master->lock.hw_lock->lock));
	}
}
Commit	Line	Data
1da177e4	1	/**
b5e89ed5	2	* \file drm_lock.c
1da177e4	3	* IOCTLs for locking
b5e89ed5	4	*
1da177e4 LT	5	* \author Rickard E. (Rik) Faith <faith@valinux.com>
	6	* \author Gareth Hughes <gareth@valinux.com>
	7	*/
	8
	9	/*
	10	* Created: Tue Feb 2 08:37:54 1999 by faith@valinux.com
	11	*
	12	* Copyright 1999 Precision Insight, Inc., Cedar Park, Texas.
	13	* Copyright 2000 VA Linux Systems, Inc., Sunnyvale, California.
	14	* All Rights Reserved.
	15	*
	16	* Permission is hereby granted, free of charge, to any person obtaining a
	17	* copy of this software and associated documentation files (the "Software"),
	18	* to deal in the Software without restriction, including without limitation
	19	* the rights to use, copy, modify, merge, publish, distribute, sublicense,
	20	* and/or sell copies of the Software, and to permit persons to whom the
	21	* Software is furnished to do so, subject to the following conditions:
	22	*
	23	* The above copyright notice and this permission notice (including the next
	24	* paragraph) shall be included in all copies or substantial portions of the
	25	* Software.
	26	*
	27	* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
	28	* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
	29	* FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
	30	* VA LINUX SYSTEMS AND/OR ITS SUPPLIERS BE LIABLE FOR ANY CLAIM, DAMAGES OR
	31	* OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE,
	32	* ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR
	33	* OTHER DEALINGS IN THE SOFTWARE.
	34	*/
	35
5c2a5ce6	36	#include <linux/export.h>
760285e7	37	#include <drm/drmP.h>
e7b96070	38	#include "drm_legacy.h"
44af3f5c	39	#include "drm_internal.h"
1da177e4	40
4ac5ec40 DV	41	static int drm_lock_take(struct drm_lock_data *lock_data, unsigned int context);
4ac5ec40 DV	42
1a75a222 DV	43	/**
	44	* Take the heavyweight lock.
	45	*
	46	* \param lock lock pointer.
	47	* \param context locking context.
	48	* \return one if the lock is held, or zero otherwise.
	49	*
	50	* Attempt to mark the lock as held by the given context, via the \p cmpxchg instruction.
	51	*/
	52	static
	53	int drm_lock_take(struct drm_lock_data *lock_data,
	54	unsigned int context)
	55	{
	56	unsigned int old, new, prev;
	57	volatile unsigned int *lock = &lock_data->hw_lock->lock;
	58
	59	spin_lock_bh(&lock_data->spinlock);
	60	do {
	61	old = *lock;
	62	if (old & _DRM_LOCK_HELD)
	63	new = old \| _DRM_LOCK_CONT;
	64	else {
	65	new = context \| _DRM_LOCK_HELD \|
	66	((lock_data->user_waiters + lock_data->kernel_waiters > 1) ?
	67	_DRM_LOCK_CONT : 0);
	68	}
	69	prev = cmpxchg(lock, old, new);
	70	} while (prev != old);
	71	spin_unlock_bh(&lock_data->spinlock);
	72
	73	if (_DRM_LOCKING_CONTEXT(old) == context) {
	74	if (old & _DRM_LOCK_HELD) {
	75	if (context != DRM_KERNEL_CONTEXT) {
	76	DRM_ERROR("%d holds heavyweight lock\n",
	77	context);
	78	}
	79	return 0;
	80	}
	81	}
	82
	83	if ((_DRM_LOCKING_CONTEXT(new)) == context && (new & _DRM_LOCK_HELD)) {
	84	/* Have lock */
	85	return 1;
	86	}
	87	return 0;
	88	}
	89
	90	/**
	91	* This takes a lock forcibly and hands it to context. Should ONLY be used
	92	* inside _unlock to give lock to kernel before calling _dma_schedule.
	93	*
	94	* \param dev DRM device.
	95	* \param lock lock pointer.
	96	* \param context locking context.
	97	* \return always one.
	98	*
	99	* Resets the lock file pointer.
	100	* Marks the lock as held by the given context, via the \p cmpxchg instruction.
	101	*/
	102	static int drm_lock_transfer(struct drm_lock_data *lock_data,
	103	unsigned int context)
	104	{
	105	unsigned int old, new, prev;
	106	volatile unsigned int *lock = &lock_data->hw_lock->lock;
107
108	lock_data->file_priv = NULL;
109	do {
110	old = *lock;
111	new = context \| _DRM_LOCK_HELD;
112	prev = cmpxchg(lock, old, new);
113	} while (prev != old);
114	return 1;
115	}
116
117	static int drm_legacy_lock_free(struct drm_lock_data *lock_data,
118	unsigned int context)
119	{
120	unsigned int old, new, prev;
121	volatile unsigned int *lock = &lock_data->hw_lock->lock;
122
123	spin_lock_bh(&lock_data->spinlock);
124	if (lock_data->kernel_waiters != 0) {
125	drm_lock_transfer(lock_data, 0);
126	lock_data->idle_has_lock = 1;
127	spin_unlock_bh(&lock_data->spinlock);
128	return 1;
129	}
130	spin_unlock_bh(&lock_data->spinlock);
131
132	do {
133	old = *lock;
134	new = _DRM_LOCKING_CONTEXT(old);
135	prev = cmpxchg(lock, old, new);
136	} while (prev != old);
137
138	if (_DRM_LOCK_IS_HELD(old) && _DRM_LOCKING_CONTEXT(old) != context) {
139	DRM_ERROR("%d freed heavyweight lock held by %d\n",
140	context, _DRM_LOCKING_CONTEXT(old));
141	return 1;
142	}
143	wake_up_interruptible(&lock_data->lock_queue);
144	return 0;
145	}
146
b5e89ed5	147	/**
1da177e4 LT	148	* Lock ioctl.
	149	*
	150	* \param inode device inode.
6c340eac	151	* \param file_priv DRM file private.
1da177e4 LT	152	* \param cmd command.
	153	* \param arg user argument, pointing to a drm_lock structure.
	154	* \return zero on success or negative number on failure.
	155	*
	156	* Add the current task to the lock wait queue, and attempt to take to lock.
	157	*/
bb6d822e DH	158	int drm_legacy_lock(struct drm_device dev, void data,
bb6d822e DH	159	struct drm_file *file_priv)
1da177e4	160	{
b5e89ed5	161	DECLARE_WAITQUEUE(entry, current);
c153f45f	162	struct drm_lock *lock = data;
7c1c2871	163	struct drm_master *master = file_priv->master;
b5e89ed5	164	int ret = 0;
1da177e4	165
fa538645	166	if (!drm_core_check_feature(dev, DRIVER_LEGACY))
da168d81 DV	167	return -EINVAL;
da168d81 DV	168
6c340eac	169	++file_priv->lock_count;
1da177e4	170
c153f45f	171	if (lock->context == DRM_KERNEL_CONTEXT) {
b5e89ed5	172	DRM_ERROR("Process %d using kernel context %d\n",
ba25f9dc	173	task_pid_nr(current), lock->context);
b5e89ed5 DA	174	return -EINVAL;
b5e89ed5 DA	175	}
1da177e4	176
b5e89ed5	177	DRM_DEBUG("%d (pid %d) requests lock (0x%08x), flags = 0x%08x\n",
ba25f9dc	178	lock->context, task_pid_nr(current),
a2ec1c13 CW	179	master->lock.hw_lock ? master->lock.hw_lock->lock : -1,
a2ec1c13 CW	180	lock->flags);
1da177e4	181
7c1c2871 DA	182	add_wait_queue(&master->lock.lock_queue, &entry);
	183	spin_lock_bh(&master->lock.spinlock);
	184	master->lock.user_waiters++;
	185	spin_unlock_bh(&master->lock.spinlock);
	186
1da177e4 LT	187	for (;;) {
1da177e4 LT	188	__set_current_state(TASK_INTERRUPTIBLE);
7c1c2871	189	if (!master->lock.hw_lock) {
1da177e4	190	/* Device has been unregistered */
fda714c2	191	send_sig(SIGTERM, current, 0);
1da177e4 LT	192	ret = -EINTR;
	193	break;
	194	}
7c1c2871 DA	195	if (drm_lock_take(&master->lock, lock->context)) {
	196	master->lock.file_priv = file_priv;
	197	master->lock.lock_time = jiffies;
b5e89ed5	198	break; /* Got lock */
1da177e4	199	}
b5e89ed5	200
1da177e4	201	/* Contention */
08f2e669	202	mutex_unlock(&drm_global_mutex);
1da177e4	203	schedule();
08f2e669	204	mutex_lock(&drm_global_mutex);
b5e89ed5	205	if (signal_pending(current)) {
4d77c88e	206	ret = -EINTR;
1da177e4 LT	207	break;
	208	}
	209	}
7c1c2871 DA	210	spin_lock_bh(&master->lock.spinlock);
	211	master->lock.user_waiters--;
	212	spin_unlock_bh(&master->lock.spinlock);
1da177e4	213	__set_current_state(TASK_RUNNING);
7c1c2871	214	remove_wait_queue(&master->lock.lock_queue, &entry);
1da177e4	215
c153f45f EA	216	DRM_DEBUG("%d %s\n", lock->context,
c153f45f EA	217	ret ? "interrupted" : "has lock");
040ac320	218	if (ret) return ret;
d985c108	219
3e5fc80a DA	220	/* don't set the block all signals on the master process for now
	221	* really probably not the correct answer but lets us debug xkb
	222	* xserver for now */
b3ac9f25	223	if (!drm_is_current_master(file_priv)) {
3e5fc80a	224	dev->sigdata.context = lock->context;
7c1c2871	225	dev->sigdata.lock = master->lock.hw_lock;
3e5fc80a	226	}
b5e89ed5	227
c153f45f EA	228	if (dev->driver->dma_quiescent && (lock->flags & _DRM_LOCK_QUIESCENT))
c153f45f EA	229	{
d985c108	230	if (dev->driver->dma_quiescent(dev)) {
c153f45f EA	231	DRM_DEBUG("%d waiting for DMA quiescent\n",
c153f45f EA	232	lock->context);
20caafa6	233	return -EBUSY;
d985c108 DA	234	}
d985c108 DA	235	}
b5e89ed5	236
d985c108	237	return 0;
1da177e4 LT	238	}
1da177e4 LT	239
b5e89ed5	240	/**
1da177e4 LT	241	* Unlock ioctl.
	242	*
	243	* \param inode device inode.
6c340eac	244	* \param file_priv DRM file private.
1da177e4 LT	245	* \param cmd command.
	246	* \param arg user argument, pointing to a drm_lock structure.
	247	* \return zero on success or negative number on failure.
	248	*
	249	* Transfer and free the lock.
	250	*/
bb6d822e	251	int drm_legacy_unlock(struct drm_device dev, void data, struct drm_file *file_priv)
1da177e4	252	{
c153f45f	253	struct drm_lock *lock = data;
45ff46c5	254	struct drm_master *master = file_priv->master;
1da177e4	255
fa538645	256	if (!drm_core_check_feature(dev, DRIVER_LEGACY))
da168d81 DV	257	return -EINVAL;
da168d81 DV	258
c153f45f	259	if (lock->context == DRM_KERNEL_CONTEXT) {
b5e89ed5	260	DRM_ERROR("Process %d using kernel context %d\n",
ba25f9dc	261	task_pid_nr(current), lock->context);
1da177e4 LT	262	return -EINVAL;
	263	}
	264
bb6d822e	265	if (drm_legacy_lock_free(&master->lock, lock->context)) {
45ff46c5 DV	266	/* FIXME: Should really bail out here. */
	267	}
	268
1da177e4 LT	269	return 0;
	270	}
	271
040ac320 TH	272	/**
	273	* This function returns immediately and takes the hw lock
	274	* with the kernel context if it is free, otherwise it gets the highest priority when and if
	275	* it is eventually released.
	276	*
	277	* This guarantees that the kernel will _eventually_ have the lock _unless_ it is held
	278	* by a blocked process. (In the latter case an explicit wait for the hardware lock would cause
	279	* a deadlock, which is why the "idlelock" was invented).
	280	*
	281	* This should be sufficient to wait for GPU idle without
	282	* having to worry about starvation.
	283	*/
	284
bb6d822e	285	void drm_legacy_idlelock_take(struct drm_lock_data *lock_data)
040ac320	286	{
4a1b0714	287	int ret;
040ac320	288
f116cc56	289	spin_lock_bh(&lock_data->spinlock);
040ac320 TH	290	lock_data->kernel_waiters++;
	291	if (!lock_data->idle_has_lock) {
	292
f116cc56	293	spin_unlock_bh(&lock_data->spinlock);
040ac320	294	ret = drm_lock_take(lock_data, DRM_KERNEL_CONTEXT);
f116cc56	295	spin_lock_bh(&lock_data->spinlock);
040ac320 TH	296
	297	if (ret == 1)
	298	lock_data->idle_has_lock = 1;
	299	}
f116cc56	300	spin_unlock_bh(&lock_data->spinlock);
040ac320	301	}
bb6d822e	302	EXPORT_SYMBOL(drm_legacy_idlelock_take);
040ac320	303
bb6d822e	304	void drm_legacy_idlelock_release(struct drm_lock_data *lock_data)
040ac320 TH	305	{
	306	unsigned int old, prev;
	307	volatile unsigned int *lock = &lock_data->hw_lock->lock;
	308
f116cc56	309	spin_lock_bh(&lock_data->spinlock);
040ac320 TH	310	if (--lock_data->kernel_waiters == 0) {
	311	if (lock_data->idle_has_lock) {
	312	do {
	313	old = *lock;
	314	prev = cmpxchg(lock, old, DRM_KERNEL_CONTEXT);
	315	} while (prev != old);
	316	wake_up_interruptible(&lock_data->lock_queue);
	317	lock_data->idle_has_lock = 0;
	318	}
	319	}
f116cc56	320	spin_unlock_bh(&lock_data->spinlock);
040ac320	321	}
bb6d822e	322	EXPORT_SYMBOL(drm_legacy_idlelock_release);
040ac320	323
1a75a222 DV	324	static int drm_legacy_i_have_hw_lock(struct drm_device *dev,
1a75a222 DV	325	struct drm_file *file_priv)
040ac320	326	{
7c1c2871 DA	327	struct drm_master *master = file_priv->master;
	328	return (file_priv->lock_count && master->lock.hw_lock &&
	329	_DRM_LOCK_IS_HELD(master->lock.hw_lock->lock) &&
	330	master->lock.file_priv == file_priv);
040ac320	331	}
1a75a222 DV	332
	333	void drm_legacy_lock_release(struct drm_device dev, struct file filp)
	334	{
	335	struct drm_file *file_priv = filp->private_data;
	336
	337	/* if the master has gone away we can't do anything with the lock */
95c081c1	338	if (!dev->master)
1a75a222 DV	339	return;
	340
	341	if (drm_legacy_i_have_hw_lock(dev, file_priv)) {
	342	DRM_DEBUG("File %p released, freeing lock for context %d\n",
	343	filp, _DRM_LOCKING_CONTEXT(file_priv->master->lock.hw_lock->lock));
	344	drm_legacy_lock_free(&file_priv->master->lock,
	345	_DRM_LOCKING_CONTEXT(file_priv->master->lock.hw_lock->lock));
	346	}
	347	}