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 */
83 send_sig(SIGTERM
, current
, 0);
87 if (drm_lock_take(&master
->lock
, lock
->context
)) {
88 master
->lock
.file_priv
= file_priv
;
89 master
->lock
.lock_time
= jiffies
;
90 atomic_inc(&dev
->counts
[_DRM_STAT_LOCKS
]);
95 mutex_unlock(&drm_global_mutex
);
97 mutex_lock(&drm_global_mutex
);
98 if (signal_pending(current
)) {
103 spin_lock_bh(&master
->lock
.spinlock
);
104 master
->lock
.user_waiters
--;
105 spin_unlock_bh(&master
->lock
.spinlock
);
106 __set_current_state(TASK_RUNNING
);
107 remove_wait_queue(&master
->lock
.lock_queue
, &entry
);
109 DRM_DEBUG("%d %s\n", lock
->context
,
110 ret
? "interrupted" : "has lock");
113 /* don't set the block all signals on the master process for now
114 * really probably not the correct answer but lets us debug xkb
116 if (!file_priv
->is_master
) {
117 sigemptyset(&dev
->sigmask
);
118 sigaddset(&dev
->sigmask
, SIGSTOP
);
119 sigaddset(&dev
->sigmask
, SIGTSTP
);
120 sigaddset(&dev
->sigmask
, SIGTTIN
);
121 sigaddset(&dev
->sigmask
, SIGTTOU
);
122 dev
->sigdata
.context
= lock
->context
;
123 dev
->sigdata
.lock
= master
->lock
.hw_lock
;
124 block_all_signals(drm_notifier
, &dev
->sigdata
, &dev
->sigmask
);
127 if (dev
->driver
->dma_ready
&& (lock
->flags
& _DRM_LOCK_READY
))
128 dev
->driver
->dma_ready(dev
);
130 if (dev
->driver
->dma_quiescent
&& (lock
->flags
& _DRM_LOCK_QUIESCENT
))
132 if (dev
->driver
->dma_quiescent(dev
)) {
133 DRM_DEBUG("%d waiting for DMA quiescent\n",
139 if (dev
->driver
->kernel_context_switch
&&
140 dev
->last_context
!= lock
->context
) {
141 dev
->driver
->kernel_context_switch(dev
, dev
->last_context
,
151 * \param inode device inode.
152 * \param file_priv DRM file private.
153 * \param cmd command.
154 * \param arg user argument, pointing to a drm_lock structure.
155 * \return zero on success or negative number on failure.
157 * Transfer and free the lock.
159 int drm_unlock(struct drm_device
*dev
, void *data
, struct drm_file
*file_priv
)
161 struct drm_lock
*lock
= data
;
162 struct drm_master
*master
= file_priv
->master
;
164 if (lock
->context
== DRM_KERNEL_CONTEXT
) {
165 DRM_ERROR("Process %d using kernel context %d\n",
166 task_pid_nr(current
), lock
->context
);
170 atomic_inc(&dev
->counts
[_DRM_STAT_UNLOCKS
]);
172 /* kernel_context_switch isn't used by any of the x86 drm
173 * modules but is required by the Sparc driver.
175 if (dev
->driver
->kernel_context_switch_unlock
)
176 dev
->driver
->kernel_context_switch_unlock(dev
);
178 if (drm_lock_free(&master
->lock
, lock
->context
)) {
182 unblock_all_signals();
187 * Take the heavyweight lock.
189 * \param lock lock pointer.
190 * \param context locking context.
191 * \return one if the lock is held, or zero otherwise.
193 * Attempt to mark the lock as held by the given context, via the \p cmpxchg instruction.
195 int drm_lock_take(struct drm_lock_data
*lock_data
,
196 unsigned int context
)
198 unsigned int old
, new, prev
;
199 volatile unsigned int *lock
= &lock_data
->hw_lock
->lock
;
201 spin_lock_bh(&lock_data
->spinlock
);
204 if (old
& _DRM_LOCK_HELD
)
205 new = old
| _DRM_LOCK_CONT
;
207 new = context
| _DRM_LOCK_HELD
|
208 ((lock_data
->user_waiters
+ lock_data
->kernel_waiters
> 1) ?
211 prev
= cmpxchg(lock
, old
, new);
212 } while (prev
!= old
);
213 spin_unlock_bh(&lock_data
->spinlock
);
215 if (_DRM_LOCKING_CONTEXT(old
) == context
) {
216 if (old
& _DRM_LOCK_HELD
) {
217 if (context
!= DRM_KERNEL_CONTEXT
) {
218 DRM_ERROR("%d holds heavyweight lock\n",
225 if ((_DRM_LOCKING_CONTEXT(new)) == context
&& (new & _DRM_LOCK_HELD
)) {
231 EXPORT_SYMBOL(drm_lock_take
);
234 * This takes a lock forcibly and hands it to context. Should ONLY be used
235 * inside *_unlock to give lock to kernel before calling *_dma_schedule.
237 * \param dev DRM device.
238 * \param lock lock pointer.
239 * \param context locking context.
240 * \return always one.
242 * Resets the lock file pointer.
243 * Marks the lock as held by the given context, via the \p cmpxchg instruction.
245 static int drm_lock_transfer(struct drm_lock_data
*lock_data
,
246 unsigned int context
)
248 unsigned int old
, new, prev
;
249 volatile unsigned int *lock
= &lock_data
->hw_lock
->lock
;
251 lock_data
->file_priv
= NULL
;
254 new = context
| _DRM_LOCK_HELD
;
255 prev
= cmpxchg(lock
, old
, new);
256 } while (prev
!= old
);
263 * \param dev DRM device.
265 * \param context context.
267 * Resets the lock file pointer.
268 * Marks the lock as not held, via the \p cmpxchg instruction. Wakes any task
269 * waiting on the lock queue.
271 int drm_lock_free(struct drm_lock_data
*lock_data
, unsigned int context
)
273 unsigned int old
, new, prev
;
274 volatile unsigned int *lock
= &lock_data
->hw_lock
->lock
;
276 spin_lock_bh(&lock_data
->spinlock
);
277 if (lock_data
->kernel_waiters
!= 0) {
278 drm_lock_transfer(lock_data
, 0);
279 lock_data
->idle_has_lock
= 1;
280 spin_unlock_bh(&lock_data
->spinlock
);
283 spin_unlock_bh(&lock_data
->spinlock
);
287 new = _DRM_LOCKING_CONTEXT(old
);
288 prev
= cmpxchg(lock
, old
, new);
289 } while (prev
!= old
);
291 if (_DRM_LOCK_IS_HELD(old
) && _DRM_LOCKING_CONTEXT(old
) != context
) {
292 DRM_ERROR("%d freed heavyweight lock held by %d\n",
293 context
, _DRM_LOCKING_CONTEXT(old
));
296 wake_up_interruptible(&lock_data
->lock_queue
);
299 EXPORT_SYMBOL(drm_lock_free
);
302 * If we get here, it means that the process has called DRM_IOCTL_LOCK
303 * without calling DRM_IOCTL_UNLOCK.
305 * If the lock is not held, then let the signal proceed as usual. If the lock
306 * is held, then set the contended flag and keep the signal blocked.
308 * \param priv pointer to a drm_sigdata structure.
309 * \return one if the signal should be delivered normally, or zero if the
310 * signal should be blocked.
312 static int drm_notifier(void *priv
)
314 struct drm_sigdata
*s
= (struct drm_sigdata
*) priv
;
315 unsigned int old
, new, prev
;
317 /* Allow signal delivery if lock isn't held */
318 if (!s
->lock
|| !_DRM_LOCK_IS_HELD(s
->lock
->lock
)
319 || _DRM_LOCKING_CONTEXT(s
->lock
->lock
) != s
->context
)
322 /* Otherwise, set flag to force call to
326 new = old
| _DRM_LOCK_CONT
;
327 prev
= cmpxchg(&s
->lock
->lock
, old
, new);
328 } while (prev
!= old
);
333 * This function returns immediately and takes the hw lock
334 * with the kernel context if it is free, otherwise it gets the highest priority when and if
335 * it is eventually released.
337 * This guarantees that the kernel will _eventually_ have the lock _unless_ it is held
338 * by a blocked process. (In the latter case an explicit wait for the hardware lock would cause
339 * a deadlock, which is why the "idlelock" was invented).
341 * This should be sufficient to wait for GPU idle without
342 * having to worry about starvation.
345 void drm_idlelock_take(struct drm_lock_data
*lock_data
)
349 spin_lock_bh(&lock_data
->spinlock
);
350 lock_data
->kernel_waiters
++;
351 if (!lock_data
->idle_has_lock
) {
353 spin_unlock_bh(&lock_data
->spinlock
);
354 ret
= drm_lock_take(lock_data
, DRM_KERNEL_CONTEXT
);
355 spin_lock_bh(&lock_data
->spinlock
);
358 lock_data
->idle_has_lock
= 1;
360 spin_unlock_bh(&lock_data
->spinlock
);
362 EXPORT_SYMBOL(drm_idlelock_take
);
364 void drm_idlelock_release(struct drm_lock_data
*lock_data
)
366 unsigned int old
, prev
;
367 volatile unsigned int *lock
= &lock_data
->hw_lock
->lock
;
369 spin_lock_bh(&lock_data
->spinlock
);
370 if (--lock_data
->kernel_waiters
== 0) {
371 if (lock_data
->idle_has_lock
) {
374 prev
= cmpxchg(lock
, old
, DRM_KERNEL_CONTEXT
);
375 } while (prev
!= old
);
376 wake_up_interruptible(&lock_data
->lock_queue
);
377 lock_data
->idle_has_lock
= 0;
380 spin_unlock_bh(&lock_data
->spinlock
);
382 EXPORT_SYMBOL(drm_idlelock_release
);
385 int drm_i_have_hw_lock(struct drm_device
*dev
, struct drm_file
*file_priv
)
387 struct drm_master
*master
= file_priv
->master
;
388 return (file_priv
->lock_count
&& master
->lock
.hw_lock
&&
389 _DRM_LOCK_IS_HELD(master
->lock
.hw_lock
->lock
) &&
390 master
->lock
.file_priv
== file_priv
);
393 EXPORT_SYMBOL(drm_i_have_hw_lock
);