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;
161 void (*tasklet_func)(struct drm_device *);
163 if (lock->context == DRM_KERNEL_CONTEXT) {
164 DRM_ERROR("Process %d using kernel context %d\n",
165 current->pid, lock->context);
169 spin_lock_irqsave(&dev->tasklet_lock, irqflags);
170 tasklet_func = dev->locked_tasklet_func;
171 dev->locked_tasklet_func = NULL;
172 spin_unlock_irqrestore(&dev->tasklet_lock, irqflags);
173 if (tasklet_func != NULL)
176 atomic_inc(&dev->counts[_DRM_STAT_UNLOCKS]);
178 /* kernel_context_switch isn't used by any of the x86 drm
179 * modules but is required by the Sparc driver.
181 if (dev->driver->kernel_context_switch_unlock)
182 dev->driver->kernel_context_switch_unlock(dev);
184 if (drm_lock_free(&master->lock,lock->context)) {
185 /* FIXME: Should really bail out here. */
189 unblock_all_signals();
194 * Take the heavyweight lock.
196 * \param lock lock pointer.
197 * \param context locking context.
198 * \return one if the lock is held, or zero otherwise.
200 * Attempt to mark the lock as held by the given context, via the \p cmpxchg instruction.
202 int drm_lock_take(struct drm_lock_data *lock_data,
203 unsigned int context)
205 unsigned int old, new, prev;
206 volatile unsigned int *lock = &lock_data->hw_lock->lock;
208 spin_lock_bh(&lock_data->spinlock);
211 if (old & _DRM_LOCK_HELD)
212 new = old | _DRM_LOCK_CONT;
214 new = context | _DRM_LOCK_HELD |
215 ((lock_data->user_waiters + lock_data->kernel_waiters > 1) ?
218 prev = cmpxchg(lock, old, new);
219 } while (prev != old);
220 spin_unlock_bh(&lock_data->spinlock);
222 if (_DRM_LOCKING_CONTEXT(old) == context) {
223 if (old & _DRM_LOCK_HELD) {
224 if (context != DRM_KERNEL_CONTEXT) {
225 DRM_ERROR("%d holds heavyweight lock\n",
232 if ((_DRM_LOCKING_CONTEXT(new)) == context && (new & _DRM_LOCK_HELD)) {
241 * This takes a lock forcibly and hands it to context. Should ONLY be used
242 * inside *_unlock to give lock to kernel before calling *_dma_schedule.
244 * \param dev DRM device.
245 * \param lock lock pointer.
246 * \param context locking context.
247 * \return always one.
249 * Resets the lock file pointer.
250 * Marks the lock as held by the given context, via the \p cmpxchg instruction.
252 static int drm_lock_transfer(struct drm_lock_data *lock_data,
253 unsigned int context)
255 unsigned int old, new, prev;
256 volatile unsigned int *lock = &lock_data->hw_lock->lock;
258 lock_data->file_priv = NULL;
261 new = context | _DRM_LOCK_HELD;
262 prev = cmpxchg(lock, old, new);
263 } while (prev != old);
270 * \param dev DRM device.
272 * \param context context.
274 * Resets the lock file pointer.
275 * Marks the lock as not held, via the \p cmpxchg instruction. Wakes any task
276 * waiting on the lock queue.
278 int drm_lock_free(struct drm_lock_data *lock_data, unsigned int context)
280 unsigned int old, new, prev;
281 volatile unsigned int *lock = &lock_data->hw_lock->lock;
283 spin_lock_bh(&lock_data->spinlock);
284 if (lock_data->kernel_waiters != 0) {
285 drm_lock_transfer(lock_data, 0);
286 lock_data->idle_has_lock = 1;
287 spin_unlock_bh(&lock_data->spinlock);
290 spin_unlock_bh(&lock_data->spinlock);
294 new = _DRM_LOCKING_CONTEXT(old);
295 prev = cmpxchg(lock, old, new);
296 } while (prev != old);
298 if (_DRM_LOCK_IS_HELD(old) && _DRM_LOCKING_CONTEXT(old) != context) {
299 DRM_ERROR("%d freed heavyweight lock held by %d\n",
300 context, _DRM_LOCKING_CONTEXT(old));
303 wake_up_interruptible(&lock_data->lock_queue);
308 * If we get here, it means that the process has called DRM_IOCTL_LOCK
309 * without calling DRM_IOCTL_UNLOCK.
311 * If the lock is not held, then let the signal proceed as usual. If the lock
312 * is held, then set the contended flag and keep the signal blocked.
314 * \param priv pointer to a drm_sigdata structure.
315 * \return one if the signal should be delivered normally, or zero if the
316 * signal should be blocked.
318 static int drm_notifier(void *priv)
320 struct drm_sigdata *s = (struct drm_sigdata *) priv;
321 unsigned int old, new, prev;
323 /* Allow signal delivery if lock isn't held */
324 if (!s->lock || !_DRM_LOCK_IS_HELD(s->lock->lock)
325 || _DRM_LOCKING_CONTEXT(s->lock->lock) != s->context)
328 /* Otherwise, set flag to force call to
332 new = old | _DRM_LOCK_CONT;
333 prev = cmpxchg(&s->lock->lock, old, new);
334 } while (prev != old);
339 * This function returns immediately and takes the hw lock
340 * with the kernel context if it is free, otherwise it gets the highest priority when and if
341 * it is eventually released.
343 * This guarantees that the kernel will _eventually_ have the lock _unless_ it is held
344 * by a blocked process. (In the latter case an explicit wait for the hardware lock would cause
345 * a deadlock, which is why the "idlelock" was invented).
347 * This should be sufficient to wait for GPU idle without
348 * having to worry about starvation.
351 void drm_idlelock_take(struct drm_lock_data *lock_data)
355 spin_lock_bh(&lock_data->spinlock);
356 lock_data->kernel_waiters++;
357 if (!lock_data->idle_has_lock) {
359 spin_unlock_bh(&lock_data->spinlock);
360 ret = drm_lock_take(lock_data, DRM_KERNEL_CONTEXT);
361 spin_lock_bh(&lock_data->spinlock);
364 lock_data->idle_has_lock = 1;
366 spin_unlock_bh(&lock_data->spinlock);
368 EXPORT_SYMBOL(drm_idlelock_take);
370 void drm_idlelock_release(struct drm_lock_data *lock_data)
372 unsigned int old, prev;
373 volatile unsigned int *lock = &lock_data->hw_lock->lock;
375 spin_lock_bh(&lock_data->spinlock);
376 if (--lock_data->kernel_waiters == 0) {
377 if (lock_data->idle_has_lock) {
380 prev = cmpxchg(lock, old, DRM_KERNEL_CONTEXT);
381 } while (prev != old);
382 wake_up_interruptible(&lock_data->lock_queue);
383 lock_data->idle_has_lock = 0;
386 spin_unlock_bh(&lock_data->spinlock);
388 EXPORT_SYMBOL(drm_idlelock_release);
390 int drm_i_have_hw_lock(struct drm_device *dev, struct drm_file *file_priv)
392 struct drm_master *master = file_priv->master;
393 return (file_priv->lock_count && master->lock.hw_lock &&
394 _DRM_LOCK_IS_HELD(master->lock.hw_lock->lock) &&
395 master->lock.file_priv == file_priv);
398 EXPORT_SYMBOL(drm_i_have_hw_lock);