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_lock_take(struct drm_lock_data
*lock_data
, unsigned int context
);
44 * Take the heavyweight lock.
46 * \param lock lock pointer.
47 * \param context locking context.
48 * \return one if the lock is held, or zero otherwise.
50 * Attempt to mark the lock as held by the given context, via the \p cmpxchg instruction.
53 int drm_lock_take(struct drm_lock_data
*lock_data
,
56 unsigned int old
, new, prev
;
57 volatile unsigned int *lock
= &lock_data
->hw_lock
->lock
;
59 spin_lock_bh(&lock_data
->spinlock
);
62 if (old
& _DRM_LOCK_HELD
)
63 new = old
| _DRM_LOCK_CONT
;
65 new = context
| _DRM_LOCK_HELD
|
66 ((lock_data
->user_waiters
+ lock_data
->kernel_waiters
> 1) ?
69 prev
= cmpxchg(lock
, old
, new);
70 } while (prev
!= old
);
71 spin_unlock_bh(&lock_data
->spinlock
);
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",
83 if ((_DRM_LOCKING_CONTEXT(new)) == context
&& (new & _DRM_LOCK_HELD
)) {
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.
94 * \param dev DRM device.
95 * \param lock lock pointer.
96 * \param context locking context.
99 * Resets the lock file pointer.
100 * Marks the lock as held by the given context, via the \p cmpxchg instruction.
102 static int drm_lock_transfer(struct drm_lock_data
*lock_data
,
103 unsigned int context
)
105 unsigned int old
, new, prev
;
106 volatile unsigned int *lock
= &lock_data
->hw_lock
->lock
;
108 lock_data
->file_priv
= NULL
;
111 new = context
| _DRM_LOCK_HELD
;
112 prev
= cmpxchg(lock
, old
, new);
113 } while (prev
!= old
);
117 static int drm_legacy_lock_free(struct drm_lock_data
*lock_data
,
118 unsigned int context
)
120 unsigned int old
, new, prev
;
121 volatile unsigned int *lock
= &lock_data
->hw_lock
->lock
;
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
);
130 spin_unlock_bh(&lock_data
->spinlock
);
134 new = _DRM_LOCKING_CONTEXT(old
);
135 prev
= cmpxchg(lock
, old
, new);
136 } while (prev
!= old
);
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
));
143 wake_up_interruptible(&lock_data
->lock_queue
);
150 * \param inode device inode.
151 * \param file_priv DRM file private.
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.
156 * Add the current task to the lock wait queue, and attempt to take to lock.
158 int drm_legacy_lock(struct drm_device
*dev
, void *data
,
159 struct drm_file
*file_priv
)
161 DECLARE_WAITQUEUE(entry
, current
);
162 struct drm_lock
*lock
= data
;
163 struct drm_master
*master
= file_priv
->master
;
166 if (!drm_core_check_feature(dev
, DRIVER_LEGACY
))
169 ++file_priv
->lock_count
;
171 if (lock
->context
== DRM_KERNEL_CONTEXT
) {
172 DRM_ERROR("Process %d using kernel context %d\n",
173 task_pid_nr(current
), lock
->context
);
177 DRM_DEBUG("%d (pid %d) requests lock (0x%08x), flags = 0x%08x\n",
178 lock
->context
, task_pid_nr(current
),
179 master
->lock
.hw_lock
? master
->lock
.hw_lock
->lock
: -1,
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
);
188 __set_current_state(TASK_INTERRUPTIBLE
);
189 if (!master
->lock
.hw_lock
) {
190 /* Device has been unregistered */
191 send_sig(SIGTERM
, current
, 0);
195 if (drm_lock_take(&master
->lock
, lock
->context
)) {
196 master
->lock
.file_priv
= file_priv
;
197 master
->lock
.lock_time
= jiffies
;
198 break; /* Got lock */
202 mutex_unlock(&drm_global_mutex
);
204 mutex_lock(&drm_global_mutex
);
205 if (signal_pending(current
)) {
210 spin_lock_bh(&master
->lock
.spinlock
);
211 master
->lock
.user_waiters
--;
212 spin_unlock_bh(&master
->lock
.spinlock
);
213 __set_current_state(TASK_RUNNING
);
214 remove_wait_queue(&master
->lock
.lock_queue
, &entry
);
216 DRM_DEBUG("%d %s\n", lock
->context
,
217 ret
? "interrupted" : "has lock");
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
223 if (!drm_is_current_master(file_priv
)) {
224 dev
->sigdata
.context
= lock
->context
;
225 dev
->sigdata
.lock
= master
->lock
.hw_lock
;
228 if (dev
->driver
->dma_quiescent
&& (lock
->flags
& _DRM_LOCK_QUIESCENT
))
230 if (dev
->driver
->dma_quiescent(dev
)) {
231 DRM_DEBUG("%d waiting for DMA quiescent\n",
243 * \param inode device inode.
244 * \param file_priv DRM file private.
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.
249 * Transfer and free the lock.
251 int drm_legacy_unlock(struct drm_device
*dev
, void *data
, struct drm_file
*file_priv
)
253 struct drm_lock
*lock
= data
;
254 struct drm_master
*master
= file_priv
->master
;
256 if (!drm_core_check_feature(dev
, DRIVER_LEGACY
))
259 if (lock
->context
== DRM_KERNEL_CONTEXT
) {
260 DRM_ERROR("Process %d using kernel context %d\n",
261 task_pid_nr(current
), lock
->context
);
265 if (drm_legacy_lock_free(&master
->lock
, lock
->context
)) {
266 /* FIXME: Should really bail out here. */
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.
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).
281 * This should be sufficient to wait for GPU idle without
282 * having to worry about starvation.
285 void drm_legacy_idlelock_take(struct drm_lock_data
*lock_data
)
289 spin_lock_bh(&lock_data
->spinlock
);
290 lock_data
->kernel_waiters
++;
291 if (!lock_data
->idle_has_lock
) {
293 spin_unlock_bh(&lock_data
->spinlock
);
294 ret
= drm_lock_take(lock_data
, DRM_KERNEL_CONTEXT
);
295 spin_lock_bh(&lock_data
->spinlock
);
298 lock_data
->idle_has_lock
= 1;
300 spin_unlock_bh(&lock_data
->spinlock
);
302 EXPORT_SYMBOL(drm_legacy_idlelock_take
);
304 void drm_legacy_idlelock_release(struct drm_lock_data
*lock_data
)
306 unsigned int old
, prev
;
307 volatile unsigned int *lock
= &lock_data
->hw_lock
->lock
;
309 spin_lock_bh(&lock_data
->spinlock
);
310 if (--lock_data
->kernel_waiters
== 0) {
311 if (lock_data
->idle_has_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;
320 spin_unlock_bh(&lock_data
->spinlock
);
322 EXPORT_SYMBOL(drm_legacy_idlelock_release
);
324 static int drm_legacy_i_have_hw_lock(struct drm_device
*dev
,
325 struct drm_file
*file_priv
)
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
);
333 void drm_legacy_lock_release(struct drm_device
*dev
, struct file
*filp
)
335 struct drm_file
*file_priv
= filp
->private_data
;
337 /* if the master has gone away we can't do anything with the lock */
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
));