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.
36 #include <linux/export.h>
38 #include "drm_legacy.h"
39 #include "drm_internal.h"
41 static int drm_notifier(void *priv
);
43 static int drm_lock_take(struct drm_lock_data
*lock_data
, unsigned int context
);
48 * \param inode device inode.
49 * \param file_priv DRM file private.
51 * \param arg user argument, pointing to a drm_lock structure.
52 * \return zero on success or negative number on failure.
54 * Add the current task to the lock wait queue, and attempt to take to lock.
56 int drm_legacy_lock(struct drm_device
*dev
, void *data
,
57 struct drm_file
*file_priv
)
59 DECLARE_WAITQUEUE(entry
, current
);
60 struct drm_lock
*lock
= data
;
61 struct drm_master
*master
= file_priv
->master
;
64 if (drm_core_check_feature(dev
, DRIVER_MODESET
))
67 ++file_priv
->lock_count
;
69 if (lock
->context
== DRM_KERNEL_CONTEXT
) {
70 DRM_ERROR("Process %d using kernel context %d\n",
71 task_pid_nr(current
), lock
->context
);
75 DRM_DEBUG("%d (pid %d) requests lock (0x%08x), flags = 0x%08x\n",
76 lock
->context
, task_pid_nr(current
),
77 master
->lock
.hw_lock
->lock
, lock
->flags
);
79 add_wait_queue(&master
->lock
.lock_queue
, &entry
);
80 spin_lock_bh(&master
->lock
.spinlock
);
81 master
->lock
.user_waiters
++;
82 spin_unlock_bh(&master
->lock
.spinlock
);
85 __set_current_state(TASK_INTERRUPTIBLE
);
86 if (!master
->lock
.hw_lock
) {
87 /* Device has been unregistered */
88 send_sig(SIGTERM
, current
, 0);
92 if (drm_lock_take(&master
->lock
, lock
->context
)) {
93 master
->lock
.file_priv
= file_priv
;
94 master
->lock
.lock_time
= jiffies
;
99 mutex_unlock(&drm_global_mutex
);
101 mutex_lock(&drm_global_mutex
);
102 if (signal_pending(current
)) {
107 spin_lock_bh(&master
->lock
.spinlock
);
108 master
->lock
.user_waiters
--;
109 spin_unlock_bh(&master
->lock
.spinlock
);
110 __set_current_state(TASK_RUNNING
);
111 remove_wait_queue(&master
->lock
.lock_queue
, &entry
);
113 DRM_DEBUG("%d %s\n", lock
->context
,
114 ret
? "interrupted" : "has lock");
117 /* don't set the block all signals on the master process for now
118 * really probably not the correct answer but lets us debug xkb
120 if (!file_priv
->is_master
) {
121 sigemptyset(&dev
->sigmask
);
122 sigaddset(&dev
->sigmask
, SIGSTOP
);
123 sigaddset(&dev
->sigmask
, SIGTSTP
);
124 sigaddset(&dev
->sigmask
, SIGTTIN
);
125 sigaddset(&dev
->sigmask
, SIGTTOU
);
126 dev
->sigdata
.context
= lock
->context
;
127 dev
->sigdata
.lock
= master
->lock
.hw_lock
;
128 block_all_signals(drm_notifier
, dev
, &dev
->sigmask
);
131 if (dev
->driver
->dma_quiescent
&& (lock
->flags
& _DRM_LOCK_QUIESCENT
))
133 if (dev
->driver
->dma_quiescent(dev
)) {
134 DRM_DEBUG("%d waiting for DMA quiescent\n",
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_legacy_unlock(struct drm_device
*dev
, void *data
, struct drm_file
*file_priv
)
156 struct drm_lock
*lock
= data
;
157 struct drm_master
*master
= file_priv
->master
;
159 if (drm_core_check_feature(dev
, DRIVER_MODESET
))
162 if (lock
->context
== DRM_KERNEL_CONTEXT
) {
163 DRM_ERROR("Process %d using kernel context %d\n",
164 task_pid_nr(current
), lock
->context
);
168 if (drm_legacy_lock_free(&master
->lock
, lock
->context
)) {
169 /* FIXME: Should really bail out here. */
172 unblock_all_signals();
177 * Take the heavyweight lock.
179 * \param lock lock pointer.
180 * \param context locking context.
181 * \return one if the lock is held, or zero otherwise.
183 * Attempt to mark the lock as held by the given context, via the \p cmpxchg instruction.
186 int drm_lock_take(struct drm_lock_data
*lock_data
,
187 unsigned int context
)
189 unsigned int old
, new, prev
;
190 volatile unsigned int *lock
= &lock_data
->hw_lock
->lock
;
192 spin_lock_bh(&lock_data
->spinlock
);
195 if (old
& _DRM_LOCK_HELD
)
196 new = old
| _DRM_LOCK_CONT
;
198 new = context
| _DRM_LOCK_HELD
|
199 ((lock_data
->user_waiters
+ lock_data
->kernel_waiters
> 1) ?
202 prev
= cmpxchg(lock
, old
, new);
203 } while (prev
!= old
);
204 spin_unlock_bh(&lock_data
->spinlock
);
206 if (_DRM_LOCKING_CONTEXT(old
) == context
) {
207 if (old
& _DRM_LOCK_HELD
) {
208 if (context
!= DRM_KERNEL_CONTEXT
) {
209 DRM_ERROR("%d holds heavyweight lock\n",
216 if ((_DRM_LOCKING_CONTEXT(new)) == context
&& (new & _DRM_LOCK_HELD
)) {
224 * This takes a lock forcibly and hands it to context. Should ONLY be used
225 * inside *_unlock to give lock to kernel before calling *_dma_schedule.
227 * \param dev DRM device.
228 * \param lock lock pointer.
229 * \param context locking context.
230 * \return always one.
232 * Resets the lock file pointer.
233 * Marks the lock as held by the given context, via the \p cmpxchg instruction.
235 static int drm_lock_transfer(struct drm_lock_data
*lock_data
,
236 unsigned int context
)
238 unsigned int old
, new, prev
;
239 volatile unsigned int *lock
= &lock_data
->hw_lock
->lock
;
241 lock_data
->file_priv
= NULL
;
244 new = context
| _DRM_LOCK_HELD
;
245 prev
= cmpxchg(lock
, old
, new);
246 } while (prev
!= old
);
253 * \param dev DRM device.
255 * \param context context.
257 * Resets the lock file pointer.
258 * Marks the lock as not held, via the \p cmpxchg instruction. Wakes any task
259 * waiting on the lock queue.
261 int drm_legacy_lock_free(struct drm_lock_data
*lock_data
, unsigned int context
)
263 unsigned int old
, new, prev
;
264 volatile unsigned int *lock
= &lock_data
->hw_lock
->lock
;
266 spin_lock_bh(&lock_data
->spinlock
);
267 if (lock_data
->kernel_waiters
!= 0) {
268 drm_lock_transfer(lock_data
, 0);
269 lock_data
->idle_has_lock
= 1;
270 spin_unlock_bh(&lock_data
->spinlock
);
273 spin_unlock_bh(&lock_data
->spinlock
);
277 new = _DRM_LOCKING_CONTEXT(old
);
278 prev
= cmpxchg(lock
, old
, new);
279 } while (prev
!= old
);
281 if (_DRM_LOCK_IS_HELD(old
) && _DRM_LOCKING_CONTEXT(old
) != context
) {
282 DRM_ERROR("%d freed heavyweight lock held by %d\n",
283 context
, _DRM_LOCKING_CONTEXT(old
));
286 wake_up_interruptible(&lock_data
->lock_queue
);
291 * If we get here, it means that the process has called DRM_IOCTL_LOCK
292 * without calling DRM_IOCTL_UNLOCK.
294 * If the lock is not held, then let the signal proceed as usual. If the lock
295 * is held, then set the contended flag and keep the signal blocked.
297 * \param priv pointer to a drm_device structure.
298 * \return one if the signal should be delivered normally, or zero if the
299 * signal should be blocked.
301 static int drm_notifier(void *priv
)
303 struct drm_device
*dev
= priv
;
304 struct drm_hw_lock
*lock
= dev
->sigdata
.lock
;
305 unsigned int old
, new, prev
;
307 /* Allow signal delivery if lock isn't held */
308 if (!lock
|| !_DRM_LOCK_IS_HELD(lock
->lock
)
309 || _DRM_LOCKING_CONTEXT(lock
->lock
) != dev
->sigdata
.context
)
312 /* Otherwise, set flag to force call to
316 new = old
| _DRM_LOCK_CONT
;
317 prev
= cmpxchg(&lock
->lock
, old
, new);
318 } while (prev
!= old
);
323 * This function returns immediately and takes the hw lock
324 * with the kernel context if it is free, otherwise it gets the highest priority when and if
325 * it is eventually released.
327 * This guarantees that the kernel will _eventually_ have the lock _unless_ it is held
328 * by a blocked process. (In the latter case an explicit wait for the hardware lock would cause
329 * a deadlock, which is why the "idlelock" was invented).
331 * This should be sufficient to wait for GPU idle without
332 * having to worry about starvation.
335 void drm_legacy_idlelock_take(struct drm_lock_data
*lock_data
)
339 spin_lock_bh(&lock_data
->spinlock
);
340 lock_data
->kernel_waiters
++;
341 if (!lock_data
->idle_has_lock
) {
343 spin_unlock_bh(&lock_data
->spinlock
);
344 ret
= drm_lock_take(lock_data
, DRM_KERNEL_CONTEXT
);
345 spin_lock_bh(&lock_data
->spinlock
);
348 lock_data
->idle_has_lock
= 1;
350 spin_unlock_bh(&lock_data
->spinlock
);
352 EXPORT_SYMBOL(drm_legacy_idlelock_take
);
354 void drm_legacy_idlelock_release(struct drm_lock_data
*lock_data
)
356 unsigned int old
, prev
;
357 volatile unsigned int *lock
= &lock_data
->hw_lock
->lock
;
359 spin_lock_bh(&lock_data
->spinlock
);
360 if (--lock_data
->kernel_waiters
== 0) {
361 if (lock_data
->idle_has_lock
) {
364 prev
= cmpxchg(lock
, old
, DRM_KERNEL_CONTEXT
);
365 } while (prev
!= old
);
366 wake_up_interruptible(&lock_data
->lock_queue
);
367 lock_data
->idle_has_lock
= 0;
370 spin_unlock_bh(&lock_data
->spinlock
);
372 EXPORT_SYMBOL(drm_legacy_idlelock_release
);
374 int drm_legacy_i_have_hw_lock(struct drm_device
*dev
,
375 struct drm_file
*file_priv
)
377 struct drm_master
*master
= file_priv
->master
;
378 return (file_priv
->lock_count
&& master
->lock
.hw_lock
&&
379 _DRM_LOCK_IS_HELD(master
->lock
.hw_lock
->lock
) &&
380 master
->lock
.file_priv
== file_priv
);