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 current->pid, lock->context);
66 DRM_DEBUG("%d (pid %d) requests lock (0x%08x), flags = 0x%08x\n",
67 lock->context, current->pid,
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 */
86 if (drm_lock_take(&master->lock, lock->context)) {
87 master->lock.file_priv = file_priv;
88 master->lock.lock_time = jiffies;
89 atomic_inc(&dev->counts[_DRM_STAT_LOCKS]);
95 if (signal_pending(current)) {
100 spin_lock_bh(&master->lock.spinlock);
101 master->lock.user_waiters--;
102 spin_unlock_bh(&master->lock.spinlock);
103 __set_current_state(TASK_RUNNING);
104 remove_wait_queue(&master->lock.lock_queue, &entry);
106 DRM_DEBUG("%d %s\n", lock->context,
107 ret ? "interrupted" : "has lock");
110 /* don't set the block all signals on the master process for now
111 * really probably not the correct answer but lets us debug xkb
113 if (!file_priv->is_master) {
114 sigemptyset(&dev->sigmask);
115 sigaddset(&dev->sigmask, SIGSTOP);
116 sigaddset(&dev->sigmask, SIGTSTP);
117 sigaddset(&dev->sigmask, SIGTTIN);
118 sigaddset(&dev->sigmask, SIGTTOU);
119 dev->sigdata.context = lock->context;
120 dev->sigdata.lock = master->lock.hw_lock;
121 block_all_signals(drm_notifier, &dev->sigdata, &dev->sigmask);
124 if (dev->driver->dma_ready && (lock->flags & _DRM_LOCK_READY))
125 dev->driver->dma_ready(dev);
127 if (dev->driver->dma_quiescent && (lock->flags & _DRM_LOCK_QUIESCENT))
129 if (dev->driver->dma_quiescent(dev)) {
130 DRM_DEBUG("%d waiting for DMA quiescent\n",
136 if (dev->driver->kernel_context_switch &&
137 dev->last_context != lock->context) {
138 dev->driver->kernel_context_switch(dev, dev->last_context,
148 * \param inode device inode.
149 * \param file_priv DRM file private.
150 * \param cmd command.
151 * \param arg user argument, pointing to a drm_lock structure.
152 * \return zero on success or negative number on failure.
154 * Transfer and free the lock.
156 int drm_unlock(struct drm_device *dev, void *data, struct drm_file *file_priv)
158 struct drm_lock *lock = data;
159 struct drm_master *master = file_priv->master;
160 unsigned long irqflags;
162 if (lock->context == DRM_KERNEL_CONTEXT) {
163 DRM_ERROR("Process %d using kernel context %d\n",
164 current->pid, lock->context);
168 spin_lock_irqsave(&dev->tasklet_lock, irqflags);
170 if (dev->locked_tasklet_func) {
171 dev->locked_tasklet_func(dev);
173 dev->locked_tasklet_func = NULL;
176 spin_unlock_irqrestore(&dev->tasklet_lock, irqflags);
178 atomic_inc(&dev->counts[_DRM_STAT_UNLOCKS]);
180 /* kernel_context_switch isn't used by any of the x86 drm
181 * modules but is required by the Sparc driver.
183 if (dev->driver->kernel_context_switch_unlock)
184 dev->driver->kernel_context_switch_unlock(dev);
186 if (drm_lock_free(&master->lock,lock->context)) {
187 /* FIXME: Should really bail out here. */
191 unblock_all_signals();
196 * Take the heavyweight lock.
198 * \param lock lock pointer.
199 * \param context locking context.
200 * \return one if the lock is held, or zero otherwise.
202 * Attempt to mark the lock as held by the given context, via the \p cmpxchg instruction.
204 int drm_lock_take(struct drm_lock_data *lock_data,
205 unsigned int context)
207 unsigned int old, new, prev;
208 volatile unsigned int *lock = &lock_data->hw_lock->lock;
210 spin_lock_bh(&lock_data->spinlock);
213 if (old & _DRM_LOCK_HELD)
214 new = old | _DRM_LOCK_CONT;
216 new = context | _DRM_LOCK_HELD |
217 ((lock_data->user_waiters + lock_data->kernel_waiters > 1) ?
220 prev = cmpxchg(lock, old, new);
221 } while (prev != old);
222 spin_unlock_bh(&lock_data->spinlock);
224 if (_DRM_LOCKING_CONTEXT(old) == context) {
225 if (old & _DRM_LOCK_HELD) {
226 if (context != DRM_KERNEL_CONTEXT) {
227 DRM_ERROR("%d holds heavyweight lock\n",
234 if ((_DRM_LOCKING_CONTEXT(new)) == context && (new & _DRM_LOCK_HELD)) {
243 * This takes a lock forcibly and hands it to context. Should ONLY be used
244 * inside *_unlock to give lock to kernel before calling *_dma_schedule.
246 * \param dev DRM device.
247 * \param lock lock pointer.
248 * \param context locking context.
249 * \return always one.
251 * Resets the lock file pointer.
252 * Marks the lock as held by the given context, via the \p cmpxchg instruction.
254 static int drm_lock_transfer(struct drm_lock_data *lock_data,
255 unsigned int context)
257 unsigned int old, new, prev;
258 volatile unsigned int *lock = &lock_data->hw_lock->lock;
260 lock_data->file_priv = NULL;
263 new = context | _DRM_LOCK_HELD;
264 prev = cmpxchg(lock, old, new);
265 } while (prev != old);
272 * \param dev DRM device.
274 * \param context context.
276 * Resets the lock file pointer.
277 * Marks the lock as not held, via the \p cmpxchg instruction. Wakes any task
278 * waiting on the lock queue.
280 int drm_lock_free(struct drm_lock_data *lock_data, unsigned int context)
282 unsigned int old, new, prev;
283 volatile unsigned int *lock = &lock_data->hw_lock->lock;
285 spin_lock_bh(&lock_data->spinlock);
286 if (lock_data->kernel_waiters != 0) {
287 drm_lock_transfer(lock_data, 0);
288 lock_data->idle_has_lock = 1;
289 spin_unlock_bh(&lock_data->spinlock);
292 spin_unlock_bh(&lock_data->spinlock);
296 new = _DRM_LOCKING_CONTEXT(old);
297 prev = cmpxchg(lock, old, new);
298 } while (prev != old);
300 if (_DRM_LOCK_IS_HELD(old) && _DRM_LOCKING_CONTEXT(old) != context) {
301 DRM_ERROR("%d freed heavyweight lock held by %d\n",
302 context, _DRM_LOCKING_CONTEXT(old));
305 wake_up_interruptible(&lock_data->lock_queue);
310 * If we get here, it means that the process has called DRM_IOCTL_LOCK
311 * without calling DRM_IOCTL_UNLOCK.
313 * If the lock is not held, then let the signal proceed as usual. If the lock
314 * is held, then set the contended flag and keep the signal blocked.
316 * \param priv pointer to a drm_sigdata structure.
317 * \return one if the signal should be delivered normally, or zero if the
318 * signal should be blocked.
320 static int drm_notifier(void *priv)
322 struct drm_sigdata *s = (struct drm_sigdata *) priv;
323 unsigned int old, new, prev;
325 /* Allow signal delivery if lock isn't held */
326 if (!s->lock || !_DRM_LOCK_IS_HELD(s->lock->lock)
327 || _DRM_LOCKING_CONTEXT(s->lock->lock) != s->context)
330 /* Otherwise, set flag to force call to
334 new = old | _DRM_LOCK_CONT;
335 prev = cmpxchg(&s->lock->lock, old, new);
336 } while (prev != old);
341 * This function returns immediately and takes the hw lock
342 * with the kernel context if it is free, otherwise it gets the highest priority when and if
343 * it is eventually released.
345 * This guarantees that the kernel will _eventually_ have the lock _unless_ it is held
346 * by a blocked process. (In the latter case an explicit wait for the hardware lock would cause
347 * a deadlock, which is why the "idlelock" was invented).
349 * This should be sufficient to wait for GPU idle without
350 * having to worry about starvation.
353 void drm_idlelock_take(struct drm_lock_data *lock_data)
357 spin_lock_bh(&lock_data->spinlock);
358 lock_data->kernel_waiters++;
359 if (!lock_data->idle_has_lock) {
361 spin_unlock_bh(&lock_data->spinlock);
362 ret = drm_lock_take(lock_data, DRM_KERNEL_CONTEXT);
363 spin_lock_bh(&lock_data->spinlock);
366 lock_data->idle_has_lock = 1;
368 spin_unlock_bh(&lock_data->spinlock);
370 EXPORT_SYMBOL(drm_idlelock_take);
372 void drm_idlelock_release(struct drm_lock_data *lock_data)
374 unsigned int old, prev;
375 volatile unsigned int *lock = &lock_data->hw_lock->lock;
377 spin_lock_bh(&lock_data->spinlock);
378 if (--lock_data->kernel_waiters == 0) {
379 if (lock_data->idle_has_lock) {
382 prev = cmpxchg(lock, old, DRM_KERNEL_CONTEXT);
383 } while (prev != old);
384 wake_up_interruptible(&lock_data->lock_queue);
385 lock_data->idle_has_lock = 0;
388 spin_unlock_bh(&lock_data->spinlock);
390 EXPORT_SYMBOL(drm_idlelock_release);
392 int drm_i_have_hw_lock(struct drm_device *dev, struct drm_file *file_priv)
394 struct drm_master *master = file_priv->master;
395 return (file_priv->lock_count && master->lock.hw_lock &&
396 _DRM_LOCK_IS_HELD(master->lock.hw_lock->lock) &&
397 master->lock.file_priv == file_priv);
400 EXPORT_SYMBOL(drm_i_have_hw_lock);