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"
40 static int drm_notifier(void *priv
);
42 static int drm_lock_take(struct drm_lock_data
*lock_data
, unsigned int context
);
47 * \param inode device inode.
48 * \param file_priv DRM file private.
50 * \param arg user argument, pointing to a drm_lock structure.
51 * \return zero on success or negative number on failure.
53 * Add the current task to the lock wait queue, and attempt to take to lock.
55 int drm_lock(struct drm_device
*dev
, void *data
, struct drm_file
*file_priv
)
57 DECLARE_WAITQUEUE(entry
, current
);
58 struct drm_lock
*lock
= data
;
59 struct drm_master
*master
= file_priv
->master
;
62 ++file_priv
->lock_count
;
64 if (lock
->context
== DRM_KERNEL_CONTEXT
) {
65 DRM_ERROR("Process %d using kernel context %d\n",
66 task_pid_nr(current
), lock
->context
);
70 DRM_DEBUG("%d (pid %d) requests lock (0x%08x), flags = 0x%08x\n",
71 lock
->context
, task_pid_nr(current
),
72 master
->lock
.hw_lock
->lock
, lock
->flags
);
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
;
94 mutex_unlock(&drm_global_mutex
);
96 mutex_lock(&drm_global_mutex
);
97 if (signal_pending(current
)) {
102 spin_lock_bh(&master
->lock
.spinlock
);
103 master
->lock
.user_waiters
--;
104 spin_unlock_bh(&master
->lock
.spinlock
);
105 __set_current_state(TASK_RUNNING
);
106 remove_wait_queue(&master
->lock
.lock_queue
, &entry
);
108 DRM_DEBUG("%d %s\n", lock
->context
,
109 ret
? "interrupted" : "has lock");
112 /* don't set the block all signals on the master process for now
113 * really probably not the correct answer but lets us debug xkb
115 if (!file_priv
->is_master
) {
116 sigemptyset(&dev
->sigmask
);
117 sigaddset(&dev
->sigmask
, SIGSTOP
);
118 sigaddset(&dev
->sigmask
, SIGTSTP
);
119 sigaddset(&dev
->sigmask
, SIGTTIN
);
120 sigaddset(&dev
->sigmask
, SIGTTOU
);
121 dev
->sigdata
.context
= lock
->context
;
122 dev
->sigdata
.lock
= master
->lock
.hw_lock
;
123 block_all_signals(drm_notifier
, &dev
->sigdata
, &dev
->sigmask
);
126 if (dev
->driver
->dma_quiescent
&& (lock
->flags
& _DRM_LOCK_QUIESCENT
))
128 if (dev
->driver
->dma_quiescent(dev
)) {
129 DRM_DEBUG("%d waiting for DMA quiescent\n",
141 * \param inode device inode.
142 * \param file_priv DRM file private.
143 * \param cmd command.
144 * \param arg user argument, pointing to a drm_lock structure.
145 * \return zero on success or negative number on failure.
147 * Transfer and free the lock.
149 int drm_unlock(struct drm_device
*dev
, void *data
, struct drm_file
*file_priv
)
151 struct drm_lock
*lock
= data
;
152 struct drm_master
*master
= file_priv
->master
;
154 if (lock
->context
== DRM_KERNEL_CONTEXT
) {
155 DRM_ERROR("Process %d using kernel context %d\n",
156 task_pid_nr(current
), lock
->context
);
160 if (drm_lock_free(&master
->lock
, lock
->context
)) {
161 /* FIXME: Should really bail out here. */
164 unblock_all_signals();
169 * Take the heavyweight lock.
171 * \param lock lock pointer.
172 * \param context locking context.
173 * \return one if the lock is held, or zero otherwise.
175 * Attempt to mark the lock as held by the given context, via the \p cmpxchg instruction.
178 int drm_lock_take(struct drm_lock_data
*lock_data
,
179 unsigned int context
)
181 unsigned int old
, new, prev
;
182 volatile unsigned int *lock
= &lock_data
->hw_lock
->lock
;
184 spin_lock_bh(&lock_data
->spinlock
);
187 if (old
& _DRM_LOCK_HELD
)
188 new = old
| _DRM_LOCK_CONT
;
190 new = context
| _DRM_LOCK_HELD
|
191 ((lock_data
->user_waiters
+ lock_data
->kernel_waiters
> 1) ?
194 prev
= cmpxchg(lock
, old
, new);
195 } while (prev
!= old
);
196 spin_unlock_bh(&lock_data
->spinlock
);
198 if (_DRM_LOCKING_CONTEXT(old
) == context
) {
199 if (old
& _DRM_LOCK_HELD
) {
200 if (context
!= DRM_KERNEL_CONTEXT
) {
201 DRM_ERROR("%d holds heavyweight lock\n",
208 if ((_DRM_LOCKING_CONTEXT(new)) == context
&& (new & _DRM_LOCK_HELD
)) {
216 * This takes a lock forcibly and hands it to context. Should ONLY be used
217 * inside *_unlock to give lock to kernel before calling *_dma_schedule.
219 * \param dev DRM device.
220 * \param lock lock pointer.
221 * \param context locking context.
222 * \return always one.
224 * Resets the lock file pointer.
225 * Marks the lock as held by the given context, via the \p cmpxchg instruction.
227 static int drm_lock_transfer(struct drm_lock_data
*lock_data
,
228 unsigned int context
)
230 unsigned int old
, new, prev
;
231 volatile unsigned int *lock
= &lock_data
->hw_lock
->lock
;
233 lock_data
->file_priv
= NULL
;
236 new = context
| _DRM_LOCK_HELD
;
237 prev
= cmpxchg(lock
, old
, new);
238 } while (prev
!= old
);
245 * \param dev DRM device.
247 * \param context context.
249 * Resets the lock file pointer.
250 * Marks the lock as not held, via the \p cmpxchg instruction. Wakes any task
251 * waiting on the lock queue.
253 int drm_lock_free(struct drm_lock_data
*lock_data
, unsigned int context
)
255 unsigned int old
, new, prev
;
256 volatile unsigned int *lock
= &lock_data
->hw_lock
->lock
;
258 spin_lock_bh(&lock_data
->spinlock
);
259 if (lock_data
->kernel_waiters
!= 0) {
260 drm_lock_transfer(lock_data
, 0);
261 lock_data
->idle_has_lock
= 1;
262 spin_unlock_bh(&lock_data
->spinlock
);
265 spin_unlock_bh(&lock_data
->spinlock
);
269 new = _DRM_LOCKING_CONTEXT(old
);
270 prev
= cmpxchg(lock
, old
, new);
271 } while (prev
!= old
);
273 if (_DRM_LOCK_IS_HELD(old
) && _DRM_LOCKING_CONTEXT(old
) != context
) {
274 DRM_ERROR("%d freed heavyweight lock held by %d\n",
275 context
, _DRM_LOCKING_CONTEXT(old
));
278 wake_up_interruptible(&lock_data
->lock_queue
);
283 * If we get here, it means that the process has called DRM_IOCTL_LOCK
284 * without calling DRM_IOCTL_UNLOCK.
286 * If the lock is not held, then let the signal proceed as usual. If the lock
287 * is held, then set the contended flag and keep the signal blocked.
289 * \param priv pointer to a drm_sigdata structure.
290 * \return one if the signal should be delivered normally, or zero if the
291 * signal should be blocked.
293 static int drm_notifier(void *priv
)
295 struct drm_sigdata
*s
= (struct drm_sigdata
*) priv
;
296 unsigned int old
, new, prev
;
298 /* Allow signal delivery if lock isn't held */
299 if (!s
->lock
|| !_DRM_LOCK_IS_HELD(s
->lock
->lock
)
300 || _DRM_LOCKING_CONTEXT(s
->lock
->lock
) != s
->context
)
303 /* Otherwise, set flag to force call to
307 new = old
| _DRM_LOCK_CONT
;
308 prev
= cmpxchg(&s
->lock
->lock
, old
, new);
309 } while (prev
!= old
);
314 * This function returns immediately and takes the hw lock
315 * with the kernel context if it is free, otherwise it gets the highest priority when and if
316 * it is eventually released.
318 * This guarantees that the kernel will _eventually_ have the lock _unless_ it is held
319 * by a blocked process. (In the latter case an explicit wait for the hardware lock would cause
320 * a deadlock, which is why the "idlelock" was invented).
322 * This should be sufficient to wait for GPU idle without
323 * having to worry about starvation.
326 void drm_idlelock_take(struct drm_lock_data
*lock_data
)
330 spin_lock_bh(&lock_data
->spinlock
);
331 lock_data
->kernel_waiters
++;
332 if (!lock_data
->idle_has_lock
) {
334 spin_unlock_bh(&lock_data
->spinlock
);
335 ret
= drm_lock_take(lock_data
, DRM_KERNEL_CONTEXT
);
336 spin_lock_bh(&lock_data
->spinlock
);
339 lock_data
->idle_has_lock
= 1;
341 spin_unlock_bh(&lock_data
->spinlock
);
343 EXPORT_SYMBOL(drm_idlelock_take
);
345 void drm_idlelock_release(struct drm_lock_data
*lock_data
)
347 unsigned int old
, prev
;
348 volatile unsigned int *lock
= &lock_data
->hw_lock
->lock
;
350 spin_lock_bh(&lock_data
->spinlock
);
351 if (--lock_data
->kernel_waiters
== 0) {
352 if (lock_data
->idle_has_lock
) {
355 prev
= cmpxchg(lock
, old
, DRM_KERNEL_CONTEXT
);
356 } while (prev
!= old
);
357 wake_up_interruptible(&lock_data
->lock_queue
);
358 lock_data
->idle_has_lock
= 0;
361 spin_unlock_bh(&lock_data
->spinlock
);
363 EXPORT_SYMBOL(drm_idlelock_release
);
365 int drm_i_have_hw_lock(struct drm_device
*dev
, struct drm_file
*file_priv
)
367 struct drm_master
*master
= file_priv
->master
;
368 return (file_priv
->lock_count
&& master
->lock
.hw_lock
&&
369 _DRM_LOCK_IS_HELD(master
->lock
.hw_lock
->lock
) &&
370 master
->lock
.file_priv
== file_priv
);
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