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, &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_device 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_device *dev = priv;
296 struct drm_hw_lock *lock = dev->sigdata.lock;
297 unsigned int old, new, prev;
299 /* Allow signal delivery if lock isn't held */
300 if (!lock || !_DRM_LOCK_IS_HELD(lock->lock)
301 || _DRM_LOCKING_CONTEXT(lock->lock) != dev->sigdata.context)
304 /* Otherwise, set flag to force call to
308 new = old | _DRM_LOCK_CONT;
309 prev = cmpxchg(&lock->lock, old, new);
310 } while (prev != old);
315 * This function returns immediately and takes the hw lock
316 * with the kernel context if it is free, otherwise it gets the highest priority when and if
317 * it is eventually released.
319 * This guarantees that the kernel will _eventually_ have the lock _unless_ it is held
320 * by a blocked process. (In the latter case an explicit wait for the hardware lock would cause
321 * a deadlock, which is why the "idlelock" was invented).
323 * This should be sufficient to wait for GPU idle without
324 * having to worry about starvation.
327 void drm_idlelock_take(struct drm_lock_data *lock_data)
331 spin_lock_bh(&lock_data->spinlock);
332 lock_data->kernel_waiters++;
333 if (!lock_data->idle_has_lock) {
335 spin_unlock_bh(&lock_data->spinlock);
336 ret = drm_lock_take(lock_data, DRM_KERNEL_CONTEXT);
337 spin_lock_bh(&lock_data->spinlock);
340 lock_data->idle_has_lock = 1;
342 spin_unlock_bh(&lock_data->spinlock);
344 EXPORT_SYMBOL(drm_idlelock_take);
346 void drm_idlelock_release(struct drm_lock_data *lock_data)
348 unsigned int old, prev;
349 volatile unsigned int *lock = &lock_data->hw_lock->lock;
351 spin_lock_bh(&lock_data->spinlock);
352 if (--lock_data->kernel_waiters == 0) {
353 if (lock_data->idle_has_lock) {
356 prev = cmpxchg(lock, old, DRM_KERNEL_CONTEXT);
357 } while (prev != old);
358 wake_up_interruptible(&lock_data->lock_queue);
359 lock_data->idle_has_lock = 0;
362 spin_unlock_bh(&lock_data->spinlock);
364 EXPORT_SYMBOL(drm_idlelock_release);
366 int drm_i_have_hw_lock(struct drm_device *dev, struct drm_file *file_priv)
368 struct drm_master *master = file_priv->master;
369 return (file_priv->lock_count && master->lock.hw_lock &&
370 _DRM_LOCK_IS_HELD(master->lock.hw_lock->lock) &&
371 master->lock.file_priv == file_priv);