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;
57 ++file_priv->lock_count;
59 if (lock->context == DRM_KERNEL_CONTEXT) {
60 DRM_ERROR("Process %d using kernel context %d\n",
61 current->pid, lock->context);
65 DRM_DEBUG("%d (pid %d) requests lock (0x%08x), flags = 0x%08x\n",
66 lock->context, current->pid,
67 dev->lock.hw_lock->lock, lock->flags);
69 if (drm_core_check_feature(dev, DRIVER_DMA_QUEUE))
70 if (lock->context < 0)
73 add_wait_queue(&dev->lock.lock_queue, &entry);
74 spin_lock_bh(&dev->lock.spinlock);
75 dev->lock.user_waiters++;
76 spin_unlock_bh(&dev->lock.spinlock);
78 __set_current_state(TASK_INTERRUPTIBLE);
79 if (!dev->lock.hw_lock) {
80 /* Device has been unregistered */
84 if (drm_lock_take(&dev->lock, lock->context)) {
85 dev->lock.file_priv = file_priv;
86 dev->lock.lock_time = jiffies;
87 atomic_inc(&dev->counts[_DRM_STAT_LOCKS]);
93 if (signal_pending(current)) {
98 spin_lock_bh(&dev->lock.spinlock);
99 dev->lock.user_waiters--;
100 spin_unlock_bh(&dev->lock.spinlock);
101 __set_current_state(TASK_RUNNING);
102 remove_wait_queue(&dev->lock.lock_queue, &entry);
104 DRM_DEBUG("%d %s\n", lock->context,
105 ret ? "interrupted" : "has lock");
108 sigemptyset(&dev->sigmask);
109 sigaddset(&dev->sigmask, SIGSTOP);
110 sigaddset(&dev->sigmask, SIGTSTP);
111 sigaddset(&dev->sigmask, SIGTTIN);
112 sigaddset(&dev->sigmask, SIGTTOU);
113 dev->sigdata.context = lock->context;
114 dev->sigdata.lock = dev->lock.hw_lock;
115 block_all_signals(drm_notifier, &dev->sigdata, &dev->sigmask);
117 if (dev->driver->dma_ready && (lock->flags & _DRM_LOCK_READY))
118 dev->driver->dma_ready(dev);
120 if (dev->driver->dma_quiescent && (lock->flags & _DRM_LOCK_QUIESCENT))
122 if (dev->driver->dma_quiescent(dev)) {
123 DRM_DEBUG("%d waiting for DMA quiescent\n",
129 if (dev->driver->kernel_context_switch &&
130 dev->last_context != lock->context) {
131 dev->driver->kernel_context_switch(dev, dev->last_context,
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 unsigned long irqflags;
154 if (lock->context == DRM_KERNEL_CONTEXT) {
155 DRM_ERROR("Process %d using kernel context %d\n",
156 current->pid, lock->context);
160 spin_lock_irqsave(&dev->tasklet_lock, irqflags);
162 if (dev->locked_tasklet_func) {
163 dev->locked_tasklet_func(dev);
165 dev->locked_tasklet_func = NULL;
168 spin_unlock_irqrestore(&dev->tasklet_lock, irqflags);
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(&dev->lock,lock->context)) {
179 /* FIXME: Should really bail out here. */
183 unblock_all_signals();
188 * Take the heavyweight lock.
190 * \param lock lock pointer.
191 * \param context locking context.
192 * \return one if the lock is held, or zero otherwise.
194 * Attempt to mark the lock as held by the given context, via the \p cmpxchg instruction.
196 int drm_lock_take(struct drm_lock_data *lock_data,
197 unsigned int context)
199 unsigned int old, new, prev;
200 volatile unsigned int *lock = &lock_data->hw_lock->lock;
202 spin_lock_bh(&lock_data->spinlock);
205 if (old & _DRM_LOCK_HELD)
206 new = old | _DRM_LOCK_CONT;
208 new = context | _DRM_LOCK_HELD |
209 ((lock_data->user_waiters + lock_data->kernel_waiters > 1) ?
212 prev = cmpxchg(lock, old, new);
213 } while (prev != old);
214 spin_unlock_bh(&lock_data->spinlock);
216 /* Warn on recursive locking of user contexts. */
217 if (_DRM_LOCKING_CONTEXT(old) == context && _DRM_LOCK_IS_HELD(old)) {
218 if (context != DRM_KERNEL_CONTEXT) {
219 DRM_ERROR("%d holds heavyweight lock\n",
225 return !_DRM_LOCK_IS_HELD(old);
229 * This takes a lock forcibly and hands it to context. Should ONLY be used
230 * inside *_unlock to give lock to kernel before calling *_dma_schedule.
232 * \param dev DRM device.
233 * \param lock lock pointer.
234 * \param context locking context.
235 * \return always one.
237 * Resets the lock file pointer.
238 * Marks the lock as held by the given context, via the \p cmpxchg instruction.
240 static int drm_lock_transfer(struct drm_lock_data *lock_data,
241 unsigned int context)
243 unsigned int old, new, prev;
244 volatile unsigned int *lock = &lock_data->hw_lock->lock;
246 lock_data->file_priv = NULL;
249 new = context | _DRM_LOCK_HELD;
250 prev = cmpxchg(lock, old, new);
251 } while (prev != old);
258 * \param dev DRM device.
260 * \param context context.
262 * Resets the lock file pointer.
263 * Marks the lock as not held, via the \p cmpxchg instruction. Wakes any task
264 * waiting on the lock queue.
266 int drm_lock_free(struct drm_lock_data *lock_data, unsigned int context)
268 unsigned int old, new, prev;
269 volatile unsigned int *lock = &lock_data->hw_lock->lock;
271 spin_lock_bh(&lock_data->spinlock);
272 if (lock_data->kernel_waiters != 0) {
273 drm_lock_transfer(lock_data, 0);
274 lock_data->idle_has_lock = 1;
275 spin_unlock_bh(&lock_data->spinlock);
278 spin_unlock_bh(&lock_data->spinlock);
282 new = _DRM_LOCKING_CONTEXT(old);
283 prev = cmpxchg(lock, old, new);
284 } while (prev != old);
286 if (_DRM_LOCK_IS_HELD(old) && _DRM_LOCKING_CONTEXT(old) != context) {
287 DRM_ERROR("%d freed heavyweight lock held by %d\n",
288 context, _DRM_LOCKING_CONTEXT(old));
291 wake_up_interruptible(&lock_data->lock_queue);
296 * If we get here, it means that the process has called DRM_IOCTL_LOCK
297 * without calling DRM_IOCTL_UNLOCK.
299 * If the lock is not held, then let the signal proceed as usual. If the lock
300 * is held, then set the contended flag and keep the signal blocked.
302 * \param priv pointer to a drm_sigdata structure.
303 * \return one if the signal should be delivered normally, or zero if the
304 * signal should be blocked.
306 static int drm_notifier(void *priv)
308 struct drm_sigdata *s = (struct drm_sigdata *) priv;
309 unsigned int old, new, prev;
311 /* Allow signal delivery if lock isn't held */
312 if (!s->lock || !_DRM_LOCK_IS_HELD(s->lock->lock)
313 || _DRM_LOCKING_CONTEXT(s->lock->lock) != s->context)
316 /* Otherwise, set flag to force call to
320 new = old | _DRM_LOCK_CONT;
321 prev = cmpxchg(&s->lock->lock, old, new);
322 } while (prev != old);
327 * This function returns immediately and takes the hw lock
328 * with the kernel context if it is free, otherwise it gets the highest priority when and if
329 * it is eventually released.
331 * This guarantees that the kernel will _eventually_ have the lock _unless_ it is held
332 * by a blocked process. (In the latter case an explicit wait for the hardware lock would cause
333 * a deadlock, which is why the "idlelock" was invented).
335 * This should be sufficient to wait for GPU idle without
336 * having to worry about starvation.
339 void drm_idlelock_take(struct drm_lock_data *lock_data)
343 spin_lock_bh(&lock_data->spinlock);
344 lock_data->kernel_waiters++;
345 if (!lock_data->idle_has_lock) {
347 spin_unlock_bh(&lock_data->spinlock);
348 ret = drm_lock_take(lock_data, DRM_KERNEL_CONTEXT);
349 spin_lock_bh(&lock_data->spinlock);
352 lock_data->idle_has_lock = 1;
354 spin_unlock_bh(&lock_data->spinlock);
356 EXPORT_SYMBOL(drm_idlelock_take);
358 void drm_idlelock_release(struct drm_lock_data *lock_data)
360 unsigned int old, prev;
361 volatile unsigned int *lock = &lock_data->hw_lock->lock;
363 spin_lock_bh(&lock_data->spinlock);
364 if (--lock_data->kernel_waiters == 0) {
365 if (lock_data->idle_has_lock) {
368 prev = cmpxchg(lock, old, DRM_KERNEL_CONTEXT);
369 } while (prev != old);
370 wake_up_interruptible(&lock_data->lock_queue);
371 lock_data->idle_has_lock = 0;
374 spin_unlock_bh(&lock_data->spinlock);
376 EXPORT_SYMBOL(drm_idlelock_release);
378 int drm_i_have_hw_lock(struct drm_device *dev, struct drm_file *file_priv)
381 return (file_priv->lock_count && dev->lock.hw_lock &&
382 _DRM_LOCK_IS_HELD(dev->lock.hw_lock->lock) &&
383 dev->lock.file_priv == file_priv);
386 EXPORT_SYMBOL(drm_i_have_hw_lock);