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
;
55 struct drm_master
*master
= file_priv
->master
;
58 ++file_priv
->lock_count
;
60 if (lock
->context
== DRM_KERNEL_CONTEXT
) {
61 DRM_ERROR("Process %d using kernel context %d\n",
62 task_pid_nr(current
), lock
->context
);
66 DRM_DEBUG("%d (pid %d) requests lock (0x%08x), flags = 0x%08x\n",
67 lock
->context
, task_pid_nr(current
),
68 master
->lock
.hw_lock
->lock
, lock
->flags
);
70 if (drm_core_check_feature(dev
, DRIVER_DMA_QUEUE
))
71 if (lock
->context
< 0)
74 add_wait_queue(&master
->lock
.lock_queue
, &entry
);
75 spin_lock_bh(&master
->lock
.spinlock
);
76 master
->lock
.user_waiters
++;
77 spin_unlock_bh(&master
->lock
.spinlock
);
80 __set_current_state(TASK_INTERRUPTIBLE
);
81 if (!master
->lock
.hw_lock
) {
82 /* Device has been unregistered */
86 if (drm_lock_take(&master
->lock
, lock
->context
)) {
87 master
->lock
.file_priv
= file_priv
;
88 master
->lock
.lock_time
= jiffies
;
89 atomic_inc(&dev
->counts
[_DRM_STAT_LOCKS
]);
95 if (signal_pending(current
)) {
100 spin_lock_bh(&master
->lock
.spinlock
);
101 master
->lock
.user_waiters
--;
102 spin_unlock_bh(&master
->lock
.spinlock
);
103 __set_current_state(TASK_RUNNING
);
104 remove_wait_queue(&master
->lock
.lock_queue
, &entry
);
106 DRM_DEBUG("%d %s\n", lock
->context
,
107 ret
? "interrupted" : "has lock");
110 /* don't set the block all signals on the master process for now
111 * really probably not the correct answer but lets us debug xkb
113 if (!file_priv
->is_master
) {
114 sigemptyset(&dev
->sigmask
);
115 sigaddset(&dev
->sigmask
, SIGSTOP
);
116 sigaddset(&dev
->sigmask
, SIGTSTP
);
117 sigaddset(&dev
->sigmask
, SIGTTIN
);
118 sigaddset(&dev
->sigmask
, SIGTTOU
);
119 dev
->sigdata
.context
= lock
->context
;
120 dev
->sigdata
.lock
= master
->lock
.hw_lock
;
121 block_all_signals(drm_notifier
, &dev
->sigdata
, &dev
->sigmask
);
124 if (dev
->driver
->dma_ready
&& (lock
->flags
& _DRM_LOCK_READY
))
125 dev
->driver
->dma_ready(dev
);
127 if (dev
->driver
->dma_quiescent
&& (lock
->flags
& _DRM_LOCK_QUIESCENT
))
129 if (dev
->driver
->dma_quiescent(dev
)) {
130 DRM_DEBUG("%d waiting for DMA quiescent\n",
136 if (dev
->driver
->kernel_context_switch
&&
137 dev
->last_context
!= lock
->context
) {
138 dev
->driver
->kernel_context_switch(dev
, dev
->last_context
,
148 * \param inode device inode.
149 * \param file_priv DRM file private.
150 * \param cmd command.
151 * \param arg user argument, pointing to a drm_lock structure.
152 * \return zero on success or negative number on failure.
154 * Transfer and free the lock.
156 int drm_unlock(struct drm_device
*dev
, void *data
, struct drm_file
*file_priv
)
158 struct drm_lock
*lock
= data
;
159 struct drm_master
*master
= file_priv
->master
;
161 if (lock
->context
== DRM_KERNEL_CONTEXT
) {
162 DRM_ERROR("Process %d using kernel context %d\n",
163 task_pid_nr(current
), lock
->context
);
167 atomic_inc(&dev
->counts
[_DRM_STAT_UNLOCKS
]);
169 /* kernel_context_switch isn't used by any of the x86 drm
170 * modules but is required by the Sparc driver.
172 if (dev
->driver
->kernel_context_switch_unlock
)
173 dev
->driver
->kernel_context_switch_unlock(dev
);
175 if (drm_lock_free(&master
->lock
, lock
->context
)) {
176 /* FIXME: Should really bail out here. */
180 unblock_all_signals();
185 * Take the heavyweight lock.
187 * \param lock lock pointer.
188 * \param context locking context.
189 * \return one if the lock is held, or zero otherwise.
191 * Attempt to mark the lock as held by the given context, via the \p cmpxchg instruction.
193 int drm_lock_take(struct drm_lock_data
*lock_data
,
194 unsigned int context
)
196 unsigned int old
, new, prev
;
197 volatile unsigned int *lock
= &lock_data
->hw_lock
->lock
;
199 spin_lock_bh(&lock_data
->spinlock
);
202 if (old
& _DRM_LOCK_HELD
)
203 new = old
| _DRM_LOCK_CONT
;
205 new = context
| _DRM_LOCK_HELD
|
206 ((lock_data
->user_waiters
+ lock_data
->kernel_waiters
> 1) ?
209 prev
= cmpxchg(lock
, old
, new);
210 } while (prev
!= old
);
211 spin_unlock_bh(&lock_data
->spinlock
);
213 if (_DRM_LOCKING_CONTEXT(old
) == context
) {
214 if (old
& _DRM_LOCK_HELD
) {
215 if (context
!= DRM_KERNEL_CONTEXT
) {
216 DRM_ERROR("%d holds heavyweight lock\n",
223 if ((_DRM_LOCKING_CONTEXT(new)) == context
&& (new & _DRM_LOCK_HELD
)) {
229 EXPORT_SYMBOL(drm_lock_take
);
232 * This takes a lock forcibly and hands it to context. Should ONLY be used
233 * inside *_unlock to give lock to kernel before calling *_dma_schedule.
235 * \param dev DRM device.
236 * \param lock lock pointer.
237 * \param context locking context.
238 * \return always one.
240 * Resets the lock file pointer.
241 * Marks the lock as held by the given context, via the \p cmpxchg instruction.
243 static int drm_lock_transfer(struct drm_lock_data
*lock_data
,
244 unsigned int context
)
246 unsigned int old
, new, prev
;
247 volatile unsigned int *lock
= &lock_data
->hw_lock
->lock
;
249 lock_data
->file_priv
= NULL
;
252 new = context
| _DRM_LOCK_HELD
;
253 prev
= cmpxchg(lock
, old
, new);
254 } while (prev
!= old
);
261 * \param dev DRM device.
263 * \param context context.
265 * Resets the lock file pointer.
266 * Marks the lock as not held, via the \p cmpxchg instruction. Wakes any task
267 * waiting on the lock queue.
269 int drm_lock_free(struct drm_lock_data
*lock_data
, unsigned int context
)
271 unsigned int old
, new, prev
;
272 volatile unsigned int *lock
= &lock_data
->hw_lock
->lock
;
274 spin_lock_bh(&lock_data
->spinlock
);
275 if (lock_data
->kernel_waiters
!= 0) {
276 drm_lock_transfer(lock_data
, 0);
277 lock_data
->idle_has_lock
= 1;
278 spin_unlock_bh(&lock_data
->spinlock
);
281 spin_unlock_bh(&lock_data
->spinlock
);
285 new = _DRM_LOCKING_CONTEXT(old
);
286 prev
= cmpxchg(lock
, old
, new);
287 } while (prev
!= old
);
289 if (_DRM_LOCK_IS_HELD(old
) && _DRM_LOCKING_CONTEXT(old
) != context
) {
290 DRM_ERROR("%d freed heavyweight lock held by %d\n",
291 context
, _DRM_LOCKING_CONTEXT(old
));
294 wake_up_interruptible(&lock_data
->lock_queue
);
297 EXPORT_SYMBOL(drm_lock_free
);
300 * If we get here, it means that the process has called DRM_IOCTL_LOCK
301 * without calling DRM_IOCTL_UNLOCK.
303 * If the lock is not held, then let the signal proceed as usual. If the lock
304 * is held, then set the contended flag and keep the signal blocked.
306 * \param priv pointer to a drm_sigdata structure.
307 * \return one if the signal should be delivered normally, or zero if the
308 * signal should be blocked.
310 static int drm_notifier(void *priv
)
312 struct drm_sigdata
*s
= (struct drm_sigdata
*) priv
;
313 unsigned int old
, new, prev
;
315 /* Allow signal delivery if lock isn't held */
316 if (!s
->lock
|| !_DRM_LOCK_IS_HELD(s
->lock
->lock
)
317 || _DRM_LOCKING_CONTEXT(s
->lock
->lock
) != s
->context
)
320 /* Otherwise, set flag to force call to
324 new = old
| _DRM_LOCK_CONT
;
325 prev
= cmpxchg(&s
->lock
->lock
, old
, new);
326 } while (prev
!= old
);
331 * This function returns immediately and takes the hw lock
332 * with the kernel context if it is free, otherwise it gets the highest priority when and if
333 * it is eventually released.
335 * This guarantees that the kernel will _eventually_ have the lock _unless_ it is held
336 * by a blocked process. (In the latter case an explicit wait for the hardware lock would cause
337 * a deadlock, which is why the "idlelock" was invented).
339 * This should be sufficient to wait for GPU idle without
340 * having to worry about starvation.
343 void drm_idlelock_take(struct drm_lock_data
*lock_data
)
347 spin_lock_bh(&lock_data
->spinlock
);
348 lock_data
->kernel_waiters
++;
349 if (!lock_data
->idle_has_lock
) {
351 spin_unlock_bh(&lock_data
->spinlock
);
352 ret
= drm_lock_take(lock_data
, DRM_KERNEL_CONTEXT
);
353 spin_lock_bh(&lock_data
->spinlock
);
356 lock_data
->idle_has_lock
= 1;
358 spin_unlock_bh(&lock_data
->spinlock
);
360 EXPORT_SYMBOL(drm_idlelock_take
);
362 void drm_idlelock_release(struct drm_lock_data
*lock_data
)
364 unsigned int old
, prev
;
365 volatile unsigned int *lock
= &lock_data
->hw_lock
->lock
;
367 spin_lock_bh(&lock_data
->spinlock
);
368 if (--lock_data
->kernel_waiters
== 0) {
369 if (lock_data
->idle_has_lock
) {
372 prev
= cmpxchg(lock
, old
, DRM_KERNEL_CONTEXT
);
373 } while (prev
!= old
);
374 wake_up_interruptible(&lock_data
->lock_queue
);
375 lock_data
->idle_has_lock
= 0;
378 spin_unlock_bh(&lock_data
->spinlock
);
380 EXPORT_SYMBOL(drm_idlelock_release
);
383 int drm_i_have_hw_lock(struct drm_device
*dev
, struct drm_file
*file_priv
)
385 struct drm_master
*master
= file_priv
->master
;
386 return (file_priv
->lock_count
&& master
->lock
.hw_lock
&&
387 _DRM_LOCK_IS_HELD(master
->lock
.hw_lock
->lock
) &&
388 master
->lock
.file_priv
== file_priv
);
391 EXPORT_SYMBOL(drm_i_have_hw_lock
);