5 * \author Rickard E. (Rik) Faith <faith@valinux.com>
6 * \author Gareth Hughes <gareth@valinux.com>
10 * Created: Tue Feb 2 08:37:54 1999 by faith@valinux.com
12 * Copyright 1999 Precision Insight, Inc., Cedar Park, Texas.
13 * Copyright 2000 VA Linux Systems, Inc., Sunnyvale, California.
14 * All Rights Reserved.
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:
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
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.
38 static int drm_notifier(void *priv
);
43 * \param inode device inode.
44 * \param file_priv DRM file private.
46 * \param arg user argument, pointing to a drm_lock structure.
47 * \return zero on success or negative number on failure.
49 * Add the current task to the lock wait queue, and attempt to take to lock.
51 int drm_lock(struct drm_device
*dev
, void *data
, struct drm_file
*file_priv
)
53 DECLARE_WAITQUEUE(entry
, current
);
54 struct drm_lock
*lock
= data
;
57 ++file_priv
->lock_count
;
59 if (lock
->context
== DRM_KERNEL_CONTEXT
) {
60 DRM_ERROR("Process %d using kernel context %d\n",
61 task_pid_nr(current
), lock
->context
);
65 DRM_DEBUG("%d (pid %d) requests lock (0x%08x), flags = 0x%08x\n",
66 lock
->context
, task_pid_nr(current
),
67 dev
->lock
.hw_lock
->lock
, lock
->flags
);
69 if (drm_core_check_feature(dev
, DRIVER_DMA_QUEUE
))
70 if (lock
->context
< 0)
73 add_wait_queue(&dev
->lock
.lock_queue
, &entry
);
74 spin_lock_bh(&dev
->lock
.spinlock
);
75 dev
->lock
.user_waiters
++;
76 spin_unlock_bh(&dev
->lock
.spinlock
);
78 __set_current_state(TASK_INTERRUPTIBLE
);
79 if (!dev
->lock
.hw_lock
) {
80 /* Device has been unregistered */
84 if (drm_lock_take(&dev
->lock
, lock
->context
)) {
85 dev
->lock
.file_priv
= file_priv
;
86 dev
->lock
.lock_time
= jiffies
;
87 atomic_inc(&dev
->counts
[_DRM_STAT_LOCKS
]);
93 if (signal_pending(current
)) {
98 spin_lock_bh(&dev
->lock
.spinlock
);
99 dev
->lock
.user_waiters
--;
100 spin_unlock_bh(&dev
->lock
.spinlock
);
101 __set_current_state(TASK_RUNNING
);
102 remove_wait_queue(&dev
->lock
.lock_queue
, &entry
);
104 DRM_DEBUG("%d %s\n", lock
->context
,
105 ret
? "interrupted" : "has lock");
108 /* don't set the block all signals on the master process for now
109 * really probably not the correct answer but lets us debug xkb
111 if (!file_priv
->master
) {
112 sigemptyset(&dev
->sigmask
);
113 sigaddset(&dev
->sigmask
, SIGSTOP
);
114 sigaddset(&dev
->sigmask
, SIGTSTP
);
115 sigaddset(&dev
->sigmask
, SIGTTIN
);
116 sigaddset(&dev
->sigmask
, SIGTTOU
);
117 dev
->sigdata
.context
= lock
->context
;
118 dev
->sigdata
.lock
= dev
->lock
.hw_lock
;
119 block_all_signals(drm_notifier
, &dev
->sigdata
, &dev
->sigmask
);
122 if (dev
->driver
->dma_ready
&& (lock
->flags
& _DRM_LOCK_READY
))
123 dev
->driver
->dma_ready(dev
);
125 if (dev
->driver
->dma_quiescent
&& (lock
->flags
& _DRM_LOCK_QUIESCENT
))
127 if (dev
->driver
->dma_quiescent(dev
)) {
128 DRM_DEBUG("%d waiting for DMA quiescent\n",
134 if (dev
->driver
->kernel_context_switch
&&
135 dev
->last_context
!= lock
->context
) {
136 dev
->driver
->kernel_context_switch(dev
, dev
->last_context
,
146 * \param inode device inode.
147 * \param file_priv DRM file private.
148 * \param cmd command.
149 * \param arg user argument, pointing to a drm_lock structure.
150 * \return zero on success or negative number on failure.
152 * Transfer and free the lock.
154 int drm_unlock(struct drm_device
*dev
, void *data
, struct drm_file
*file_priv
)
156 struct drm_lock
*lock
= data
;
157 unsigned long irqflags
;
158 void (*tasklet_func
)(struct drm_device
*);
160 if (lock
->context
== DRM_KERNEL_CONTEXT
) {
161 DRM_ERROR("Process %d using kernel context %d\n",
162 task_pid_nr(current
), lock
->context
);
166 spin_lock_irqsave(&dev
->tasklet_lock
, irqflags
);
167 tasklet_func
= dev
->locked_tasklet_func
;
168 dev
->locked_tasklet_func
= NULL
;
169 spin_unlock_irqrestore(&dev
->tasklet_lock
, irqflags
);
170 if (tasklet_func
!= NULL
)
173 atomic_inc(&dev
->counts
[_DRM_STAT_UNLOCKS
]);
175 /* kernel_context_switch isn't used by any of the x86 drm
176 * modules but is required by the Sparc driver.
178 if (dev
->driver
->kernel_context_switch_unlock
)
179 dev
->driver
->kernel_context_switch_unlock(dev
);
181 if (drm_lock_free(&dev
->lock
,lock
->context
)) {
182 /* FIXME: Should really bail out here. */
186 unblock_all_signals();
191 * Take the heavyweight lock.
193 * \param lock lock pointer.
194 * \param context locking context.
195 * \return one if the lock is held, or zero otherwise.
197 * Attempt to mark the lock as held by the given context, via the \p cmpxchg instruction.
199 int drm_lock_take(struct drm_lock_data
*lock_data
,
200 unsigned int context
)
202 unsigned int old
, new, prev
;
203 volatile unsigned int *lock
= &lock_data
->hw_lock
->lock
;
205 spin_lock_bh(&lock_data
->spinlock
);
208 if (old
& _DRM_LOCK_HELD
)
209 new = old
| _DRM_LOCK_CONT
;
211 new = context
| _DRM_LOCK_HELD
|
212 ((lock_data
->user_waiters
+ lock_data
->kernel_waiters
> 1) ?
215 prev
= cmpxchg(lock
, old
, new);
216 } while (prev
!= old
);
217 spin_unlock_bh(&lock_data
->spinlock
);
219 if (_DRM_LOCKING_CONTEXT(old
) == context
) {
220 if (old
& _DRM_LOCK_HELD
) {
221 if (context
!= DRM_KERNEL_CONTEXT
) {
222 DRM_ERROR("%d holds heavyweight lock\n",
229 if ((_DRM_LOCKING_CONTEXT(new)) == context
&& (new & _DRM_LOCK_HELD
)) {
235 EXPORT_SYMBOL(drm_lock_take
);
238 * This takes a lock forcibly and hands it to context. Should ONLY be used
239 * inside *_unlock to give lock to kernel before calling *_dma_schedule.
241 * \param dev DRM device.
242 * \param lock lock pointer.
243 * \param context locking context.
244 * \return always one.
246 * Resets the lock file pointer.
247 * Marks the lock as held by the given context, via the \p cmpxchg instruction.
249 static int drm_lock_transfer(struct drm_lock_data
*lock_data
,
250 unsigned int context
)
252 unsigned int old
, new, prev
;
253 volatile unsigned int *lock
= &lock_data
->hw_lock
->lock
;
255 lock_data
->file_priv
= NULL
;
258 new = context
| _DRM_LOCK_HELD
;
259 prev
= cmpxchg(lock
, old
, new);
260 } while (prev
!= old
);
267 * \param dev DRM device.
269 * \param context context.
271 * Resets the lock file pointer.
272 * Marks the lock as not held, via the \p cmpxchg instruction. Wakes any task
273 * waiting on the lock queue.
275 int drm_lock_free(struct drm_lock_data
*lock_data
, unsigned int context
)
277 unsigned int old
, new, prev
;
278 volatile unsigned int *lock
= &lock_data
->hw_lock
->lock
;
280 spin_lock_bh(&lock_data
->spinlock
);
281 if (lock_data
->kernel_waiters
!= 0) {
282 drm_lock_transfer(lock_data
, 0);
283 lock_data
->idle_has_lock
= 1;
284 spin_unlock_bh(&lock_data
->spinlock
);
287 spin_unlock_bh(&lock_data
->spinlock
);
291 new = _DRM_LOCKING_CONTEXT(old
);
292 prev
= cmpxchg(lock
, old
, new);
293 } while (prev
!= old
);
295 if (_DRM_LOCK_IS_HELD(old
) && _DRM_LOCKING_CONTEXT(old
) != context
) {
296 DRM_ERROR("%d freed heavyweight lock held by %d\n",
297 context
, _DRM_LOCKING_CONTEXT(old
));
300 wake_up_interruptible(&lock_data
->lock_queue
);
303 EXPORT_SYMBOL(drm_lock_free
);
306 * If we get here, it means that the process has called DRM_IOCTL_LOCK
307 * without calling DRM_IOCTL_UNLOCK.
309 * If the lock is not held, then let the signal proceed as usual. If the lock
310 * is held, then set the contended flag and keep the signal blocked.
312 * \param priv pointer to a drm_sigdata structure.
313 * \return one if the signal should be delivered normally, or zero if the
314 * signal should be blocked.
316 static int drm_notifier(void *priv
)
318 struct drm_sigdata
*s
= (struct drm_sigdata
*) priv
;
319 unsigned int old
, new, prev
;
321 /* Allow signal delivery if lock isn't held */
322 if (!s
->lock
|| !_DRM_LOCK_IS_HELD(s
->lock
->lock
)
323 || _DRM_LOCKING_CONTEXT(s
->lock
->lock
) != s
->context
)
326 /* Otherwise, set flag to force call to
330 new = old
| _DRM_LOCK_CONT
;
331 prev
= cmpxchg(&s
->lock
->lock
, old
, new);
332 } while (prev
!= old
);
337 * This function returns immediately and takes the hw lock
338 * with the kernel context if it is free, otherwise it gets the highest priority when and if
339 * it is eventually released.
341 * This guarantees that the kernel will _eventually_ have the lock _unless_ it is held
342 * by a blocked process. (In the latter case an explicit wait for the hardware lock would cause
343 * a deadlock, which is why the "idlelock" was invented).
345 * This should be sufficient to wait for GPU idle without
346 * having to worry about starvation.
349 void drm_idlelock_take(struct drm_lock_data
*lock_data
)
353 spin_lock_bh(&lock_data
->spinlock
);
354 lock_data
->kernel_waiters
++;
355 if (!lock_data
->idle_has_lock
) {
357 spin_unlock_bh(&lock_data
->spinlock
);
358 ret
= drm_lock_take(lock_data
, DRM_KERNEL_CONTEXT
);
359 spin_lock_bh(&lock_data
->spinlock
);
362 lock_data
->idle_has_lock
= 1;
364 spin_unlock_bh(&lock_data
->spinlock
);
366 EXPORT_SYMBOL(drm_idlelock_take
);
368 void drm_idlelock_release(struct drm_lock_data
*lock_data
)
370 unsigned int old
, prev
;
371 volatile unsigned int *lock
= &lock_data
->hw_lock
->lock
;
373 spin_lock_bh(&lock_data
->spinlock
);
374 if (--lock_data
->kernel_waiters
== 0) {
375 if (lock_data
->idle_has_lock
) {
378 prev
= cmpxchg(lock
, old
, DRM_KERNEL_CONTEXT
);
379 } while (prev
!= old
);
380 wake_up_interruptible(&lock_data
->lock_queue
);
381 lock_data
->idle_has_lock
= 0;
384 spin_unlock_bh(&lock_data
->spinlock
);
386 EXPORT_SYMBOL(drm_idlelock_release
);
389 int drm_i_have_hw_lock(struct drm_device
*dev
, struct drm_file
*file_priv
)
391 return (file_priv
->lock_count
&& dev
->lock
.hw_lock
&&
392 _DRM_LOCK_IS_HELD(dev
->lock
.hw_lock
->lock
) &&
393 dev
->lock
.file_priv
== file_priv
);
396 EXPORT_SYMBOL(drm_i_have_hw_lock
);