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 filp file pointer.
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 inode *inode, struct file *filp,
52 unsigned int cmd, unsigned long arg)
54 drm_file_t *priv = filp->private_data;
55 drm_device_t *dev = priv->head->dev;
56 DECLARE_WAITQUEUE(entry, current);
62 if (copy_from_user(&lock, (drm_lock_t __user *) arg, sizeof(lock)))
65 if (lock.context == DRM_KERNEL_CONTEXT) {
66 DRM_ERROR("Process %d using kernel context %d\n",
67 current->pid, lock.context);
71 DRM_DEBUG("%d (pid %d) requests lock (0x%08x), flags = 0x%08x\n",
72 lock.context, current->pid,
73 dev->lock.hw_lock->lock, lock.flags);
75 if (drm_core_check_feature(dev, DRIVER_DMA_QUEUE))
79 add_wait_queue(&dev->lock.lock_queue, &entry);
80 spin_lock(&dev->lock.spinlock);
81 dev->lock.user_waiters++;
82 spin_unlock(&dev->lock.spinlock);
84 __set_current_state(TASK_INTERRUPTIBLE);
85 if (!dev->lock.hw_lock) {
86 /* Device has been unregistered */
90 if (drm_lock_take(&dev->lock, lock.context)) {
91 dev->lock.filp = filp;
92 dev->lock.lock_time = jiffies;
93 atomic_inc(&dev->counts[_DRM_STAT_LOCKS]);
99 if (signal_pending(current)) {
104 spin_lock(&dev->lock.spinlock);
105 dev->lock.user_waiters--;
106 spin_unlock(&dev->lock.spinlock);
107 __set_current_state(TASK_RUNNING);
108 remove_wait_queue(&dev->lock.lock_queue, &entry);
110 DRM_DEBUG( "%d %s\n", lock.context, ret ? "interrupted" : "has lock" );
113 sigemptyset(&dev->sigmask);
114 sigaddset(&dev->sigmask, SIGSTOP);
115 sigaddset(&dev->sigmask, SIGTSTP);
116 sigaddset(&dev->sigmask, SIGTTIN);
117 sigaddset(&dev->sigmask, SIGTTOU);
118 dev->sigdata.context = lock.context;
119 dev->sigdata.lock = dev->lock.hw_lock;
120 block_all_signals(drm_notifier, &dev->sigdata, &dev->sigmask);
122 if (dev->driver->dma_ready && (lock.flags & _DRM_LOCK_READY))
123 dev->driver->dma_ready(dev);
125 if (dev->driver->dma_quiescent && (lock.flags & _DRM_LOCK_QUIESCENT)) {
126 if (dev->driver->dma_quiescent(dev)) {
127 DRM_DEBUG( "%d waiting for DMA quiescent\n", lock.context);
128 return DRM_ERR(EBUSY);
132 if (dev->driver->kernel_context_switch &&
133 dev->last_context != lock.context) {
134 dev->driver->kernel_context_switch(dev, dev->last_context,
144 * \param inode device inode.
145 * \param filp file pointer.
146 * \param cmd command.
147 * \param arg user argument, pointing to a drm_lock structure.
148 * \return zero on success or negative number on failure.
150 * Transfer and free the lock.
152 int drm_unlock(struct inode *inode, struct file *filp,
153 unsigned int cmd, unsigned long arg)
155 drm_file_t *priv = filp->private_data;
156 drm_device_t *dev = priv->head->dev;
158 unsigned long irqflags;
160 if (copy_from_user(&lock, (drm_lock_t __user *) arg, sizeof(lock)))
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);
171 if (dev->locked_tasklet_func) {
172 dev->locked_tasklet_func(dev);
174 dev->locked_tasklet_func = NULL;
177 spin_unlock_irqrestore(&dev->tasklet_lock, irqflags);
179 atomic_inc(&dev->counts[_DRM_STAT_UNLOCKS]);
181 /* kernel_context_switch isn't used by any of the x86 drm
182 * modules but is required by the Sparc driver.
184 if (dev->driver->kernel_context_switch_unlock)
185 dev->driver->kernel_context_switch_unlock(dev);
187 if (drm_lock_free(&dev->lock,lock.context)) {
188 /* FIXME: Should really bail out here. */
192 unblock_all_signals();
197 * Take the heavyweight lock.
199 * \param lock lock pointer.
200 * \param context locking context.
201 * \return one if the lock is held, or zero otherwise.
203 * Attempt to mark the lock as held by the given context, via the \p cmpxchg instruction.
205 int drm_lock_take(drm_lock_data_t *lock_data,
206 unsigned int context)
208 unsigned int old, new, prev;
209 volatile unsigned int *lock = &lock_data->hw_lock->lock;
211 spin_lock(&lock_data->spinlock);
214 if (old & _DRM_LOCK_HELD)
215 new = old | _DRM_LOCK_CONT;
217 new = context | _DRM_LOCK_HELD |
218 ((lock_data->user_waiters + lock_data->kernel_waiters > 1) ?
221 prev = cmpxchg(lock, old, new);
222 } while (prev != old);
223 spin_unlock(&lock_data->spinlock);
225 if (_DRM_LOCKING_CONTEXT(old) == context) {
226 if (old & _DRM_LOCK_HELD) {
227 if (context != DRM_KERNEL_CONTEXT) {
228 DRM_ERROR("%d holds heavyweight lock\n",
235 if ((_DRM_LOCKING_CONTEXT(new)) == context && (new & _DRM_LOCK_HELD)) {
244 * This takes a lock forcibly and hands it to context. Should ONLY be used
245 * inside *_unlock to give lock to kernel before calling *_dma_schedule.
247 * \param dev DRM device.
248 * \param lock lock pointer.
249 * \param context locking context.
250 * \return always one.
252 * Resets the lock file pointer.
253 * Marks the lock as held by the given context, via the \p cmpxchg instruction.
255 static int drm_lock_transfer(drm_lock_data_t *lock_data,
256 unsigned int context)
258 unsigned int old, new, prev;
259 volatile unsigned int *lock = &lock_data->hw_lock->lock;
261 lock_data->filp = NULL;
264 new = context | _DRM_LOCK_HELD;
265 prev = cmpxchg(lock, old, new);
266 } while (prev != old);
273 * \param dev DRM device.
275 * \param context context.
277 * Resets the lock file pointer.
278 * Marks the lock as not held, via the \p cmpxchg instruction. Wakes any task
279 * waiting on the lock queue.
281 int drm_lock_free(drm_lock_data_t *lock_data, unsigned int context)
283 unsigned int old, new, prev;
284 volatile unsigned int *lock = &lock_data->hw_lock->lock;
286 spin_lock(&lock_data->spinlock);
287 if (lock_data->kernel_waiters != 0) {
288 drm_lock_transfer(lock_data, 0);
289 lock_data->idle_has_lock = 1;
290 spin_unlock(&lock_data->spinlock);
293 spin_unlock(&lock_data->spinlock);
297 new = _DRM_LOCKING_CONTEXT(old);
298 prev = cmpxchg(lock, old, new);
299 } while (prev != old);
301 if (_DRM_LOCK_IS_HELD(old) && _DRM_LOCKING_CONTEXT(old) != context) {
302 DRM_ERROR("%d freed heavyweight lock held by %d\n",
303 context, _DRM_LOCKING_CONTEXT(old));
306 wake_up_interruptible(&lock_data->lock_queue);
311 * If we get here, it means that the process has called DRM_IOCTL_LOCK
312 * without calling DRM_IOCTL_UNLOCK.
314 * If the lock is not held, then let the signal proceed as usual. If the lock
315 * is held, then set the contended flag and keep the signal blocked.
317 * \param priv pointer to a drm_sigdata structure.
318 * \return one if the signal should be delivered normally, or zero if the
319 * signal should be blocked.
321 static int drm_notifier(void *priv)
323 drm_sigdata_t *s = (drm_sigdata_t *) priv;
324 unsigned int old, new, prev;
326 /* Allow signal delivery if lock isn't held */
327 if (!s->lock || !_DRM_LOCK_IS_HELD(s->lock->lock)
328 || _DRM_LOCKING_CONTEXT(s->lock->lock) != s->context)
331 /* Otherwise, set flag to force call to
335 new = old | _DRM_LOCK_CONT;
336 prev = cmpxchg(&s->lock->lock, old, new);
337 } while (prev != old);
342 * This function returns immediately and takes the hw lock
343 * with the kernel context if it is free, otherwise it gets the highest priority when and if
344 * it is eventually released.
346 * This guarantees that the kernel will _eventually_ have the lock _unless_ it is held
347 * by a blocked process. (In the latter case an explicit wait for the hardware lock would cause
348 * a deadlock, which is why the "idlelock" was invented).
350 * This should be sufficient to wait for GPU idle without
351 * having to worry about starvation.
354 void drm_idlelock_take(drm_lock_data_t *lock_data)
358 spin_lock(&lock_data->spinlock);
359 lock_data->kernel_waiters++;
360 if (!lock_data->idle_has_lock) {
362 spin_unlock(&lock_data->spinlock);
363 ret = drm_lock_take(lock_data, DRM_KERNEL_CONTEXT);
364 spin_lock(&lock_data->spinlock);
367 lock_data->idle_has_lock = 1;
369 spin_unlock(&lock_data->spinlock);
371 EXPORT_SYMBOL(drm_idlelock_take);
373 void drm_idlelock_release(drm_lock_data_t *lock_data)
375 unsigned int old, prev;
376 volatile unsigned int *lock = &lock_data->hw_lock->lock;
378 spin_lock(&lock_data->spinlock);
379 if (--lock_data->kernel_waiters == 0) {
380 if (lock_data->idle_has_lock) {
383 prev = cmpxchg(lock, old, DRM_KERNEL_CONTEXT);
384 } while (prev != old);
385 wake_up_interruptible(&lock_data->lock_queue);
386 lock_data->idle_has_lock = 0;
389 spin_unlock(&lock_data->spinlock);
391 EXPORT_SYMBOL(drm_idlelock_release);
394 int drm_i_have_hw_lock(struct file *filp)
398 return (priv->lock_count && dev->lock.hw_lock &&
399 _DRM_LOCK_IS_HELD(dev->lock.hw_lock->lock) &&
400 dev->lock.filp == filp);
403 EXPORT_SYMBOL(drm_i_have_hw_lock);