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"
39 #include "drm_internal.h"
42 static int drm_lock_take(struct drm_lock_data *lock_data, unsigned int context);
48 * \param inode device inode.
49 * \param file_priv DRM file private.
51 * \param arg user argument, pointing to a drm_lock structure.
52 * \return zero on success or negative number on failure.
54 * Add the current task to the lock wait queue, and attempt to take to lock.
56 int drm_legacy_lock(struct drm_device *dev, void *data,
57 struct drm_file *file_priv)
60 DECLARE_WAITQUEUE(entry, current);
61 struct drm_lock *lock = data;
62 struct drm_master *master = file_priv->master;
65 if (drm_core_check_feature(dev, DRIVER_MODESET))
68 ++file_priv->lock_count;
70 if (lock->context == DRM_KERNEL_CONTEXT) {
71 DRM_ERROR("Process %d using kernel context %d\n",
72 task_pid_nr(current), lock->context);
76 DRM_DEBUG("%d (pid %d) requests lock (0x%08x), flags = 0x%08x\n",
77 lock->context, task_pid_nr(current),
78 master->lock.hw_lock->lock, lock->flags);
80 add_wait_queue(&master->lock.lock_queue, &entry);
81 spin_lock_bh(&master->lock.spinlock);
82 master->lock.user_waiters++;
83 spin_unlock_bh(&master->lock.spinlock);
86 __set_current_state(TASK_INTERRUPTIBLE);
87 if (!master->lock.hw_lock) {
88 /* Device has been unregistered */
89 send_sig(SIGTERM, current, 0);
93 if (drm_lock_take(&master->lock, lock->context)) {
94 master->lock.file_priv = file_priv;
95 master->lock.lock_time = jiffies;
100 mutex_unlock(&drm_global_mutex);
102 mutex_lock(&drm_global_mutex);
103 if (signal_pending(current)) {
108 spin_lock_bh(&master->lock.spinlock);
109 master->lock.user_waiters--;
110 spin_unlock_bh(&master->lock.spinlock);
111 __set_current_state(TASK_RUNNING);
112 remove_wait_queue(&master->lock.lock_queue, &entry);
114 DRM_DEBUG("%d %s\n", lock->context,
115 ret ? "interrupted" : "has lock");
118 /* don't set the block all signals on the master process for now
119 * really probably not the correct answer but lets us debug xkb
121 if (!file_priv->is_master) {
122 dev->sigdata.context = lock->context;
123 dev->sigdata.lock = master->lock.hw_lock;
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",
142 * \param inode device inode.
143 * \param file_priv DRM file private.
144 * \param cmd command.
145 * \param arg user argument, pointing to a drm_lock structure.
146 * \return zero on success or negative number on failure.
148 * Transfer and free the lock.
150 int drm_legacy_unlock(struct drm_device *dev, void *data, struct drm_file *file_priv)
153 struct drm_lock *lock = data;
154 struct drm_master *master = file_priv->master;
156 if (drm_core_check_feature(dev, DRIVER_MODESET))
159 if (lock->context == DRM_KERNEL_CONTEXT) {
160 DRM_ERROR("Process %d using kernel context %d\n",
161 task_pid_nr(current), lock->context);
165 if (drm_legacy_lock_free(&master->lock, lock->context)) {
166 /* FIXME: Should really bail out here. */
169 unblock_all_signals();
176 * Take the heavyweight lock.
178 * \param lock lock pointer.
179 * \param context locking context.
180 * \return one if the lock is held, or zero otherwise.
182 * Attempt to mark the lock as held by the given context, via the \p cmpxchg instruction.
185 int drm_lock_take(struct drm_lock_data *lock_data,
186 unsigned int context)
188 unsigned int old, new, prev;
189 volatile unsigned int *lock = &lock_data->hw_lock->lock;
191 spin_lock_bh(&lock_data->spinlock);
194 if (old & _DRM_LOCK_HELD)
195 new = old | _DRM_LOCK_CONT;
197 new = context | _DRM_LOCK_HELD |
198 ((lock_data->user_waiters + lock_data->kernel_waiters > 1) ?
201 prev = cmpxchg(lock, old, new);
202 } while (prev != old);
203 spin_unlock_bh(&lock_data->spinlock);
205 if (_DRM_LOCKING_CONTEXT(old) == context) {
206 if (old & _DRM_LOCK_HELD) {
207 if (context != DRM_KERNEL_CONTEXT) {
208 DRM_ERROR("%d holds heavyweight lock\n",
215 if ((_DRM_LOCKING_CONTEXT(new)) == context && (new & _DRM_LOCK_HELD)) {
223 * This takes a lock forcibly and hands it to context. Should ONLY be used
224 * inside *_unlock to give lock to kernel before calling *_dma_schedule.
226 * \param dev DRM device.
227 * \param lock lock pointer.
228 * \param context locking context.
229 * \return always one.
231 * Resets the lock file pointer.
232 * Marks the lock as held by the given context, via the \p cmpxchg instruction.
234 static int drm_lock_transfer(struct drm_lock_data *lock_data,
235 unsigned int context)
237 unsigned int old, new, prev;
238 volatile unsigned int *lock = &lock_data->hw_lock->lock;
240 lock_data->file_priv = NULL;
243 new = context | _DRM_LOCK_HELD;
244 prev = cmpxchg(lock, old, new);
245 } while (prev != old);
253 * \param dev DRM device.
255 * \param context context.
257 * Resets the lock file pointer.
258 * Marks the lock as not held, via the \p cmpxchg instruction. Wakes any task
259 * waiting on the lock queue.
261 int drm_legacy_lock_free(struct drm_lock_data *lock_data, unsigned int context)
264 unsigned int old, new, prev;
265 volatile unsigned int *lock = &lock_data->hw_lock->lock;
267 spin_lock_bh(&lock_data->spinlock);
268 if (lock_data->kernel_waiters != 0) {
269 drm_lock_transfer(lock_data, 0);
270 lock_data->idle_has_lock = 1;
271 spin_unlock_bh(&lock_data->spinlock);
274 spin_unlock_bh(&lock_data->spinlock);
278 new = _DRM_LOCKING_CONTEXT(old);
279 prev = cmpxchg(lock, old, new);
280 } while (prev != old);
282 if (_DRM_LOCK_IS_HELD(old) && _DRM_LOCKING_CONTEXT(old) != context) {
283 DRM_ERROR("%d freed heavyweight lock held by %d\n",
284 context, _DRM_LOCKING_CONTEXT(old));
287 wake_up_interruptible(&lock_data->lock_queue);
293 * This function returns immediately and takes the hw lock
294 * with the kernel context if it is free, otherwise it gets the highest priority when and if
295 * it is eventually released.
297 * This guarantees that the kernel will _eventually_ have the lock _unless_ it is held
298 * by a blocked process. (In the latter case an explicit wait for the hardware lock would cause
299 * a deadlock, which is why the "idlelock" was invented).
301 * This should be sufficient to wait for GPU idle without
302 * having to worry about starvation.
305 void drm_legacy_idlelock_take(struct drm_lock_data *lock_data)
310 spin_lock_bh(&lock_data->spinlock);
311 lock_data->kernel_waiters++;
312 if (!lock_data->idle_has_lock) {
314 spin_unlock_bh(&lock_data->spinlock);
315 ret = drm_lock_take(lock_data, DRM_KERNEL_CONTEXT);
316 spin_lock_bh(&lock_data->spinlock);
319 lock_data->idle_has_lock = 1;
321 spin_unlock_bh(&lock_data->spinlock);
324 EXPORT_SYMBOL(drm_legacy_idlelock_take);
326 void drm_legacy_idlelock_release(struct drm_lock_data *lock_data)
329 unsigned int old, prev;
330 volatile unsigned int *lock = &lock_data->hw_lock->lock;
332 spin_lock_bh(&lock_data->spinlock);
333 if (--lock_data->kernel_waiters == 0) {
334 if (lock_data->idle_has_lock) {
337 prev = cmpxchg(lock, old, DRM_KERNEL_CONTEXT);
338 } while (prev != old);
339 wake_up_interruptible(&lock_data->lock_queue);
340 lock_data->idle_has_lock = 0;
343 spin_unlock_bh(&lock_data->spinlock);
346 EXPORT_SYMBOL(drm_legacy_idlelock_release);
348 int drm_legacy_i_have_hw_lock(struct drm_device *dev,
349 struct drm_file *file_priv)
352 struct drm_master *master = file_priv->master;
353 return (file_priv->lock_count && master->lock.hw_lock &&
354 _DRM_LOCK_IS_HELD(master->lock.hw_lock->lock) &&
355 master->lock.file_priv == file_priv);