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/* lock.c -- IOCTLs for locking -*- linux-c -*-
* Created: Tue Feb 2 08:37:54 1999 by faith@valinux.com
*/
/*-
* Copyright 1999 Precision Insight, Inc., Cedar Park, Texas.
* Copyright 2000 VA Linux Systems, Inc., Sunnyvale, California.
* All Rights Reserved.
*
* Permission is hereby granted, free of charge, to any person obtaining a
* copy of this software and associated documentation files (the "Software"),
* to deal in the Software without restriction, including without limitation
* the rights to use, copy, modify, merge, publish, distribute, sublicense,
* and/or sell copies of the Software, and to permit persons to whom the
* Software is furnished to do so, subject to the following conditions:
*
* The above copyright notice and this permission notice (including the next
* paragraph) shall be included in all copies or substantial portions of the
* Software.
*
* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
* FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
* VA LINUX SYSTEMS AND/OR ITS SUPPLIERS BE LIABLE FOR ANY CLAIM, DAMAGES OR
* OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE,
* ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR
* OTHER DEALINGS IN THE SOFTWARE.
*
* Authors:
* Rickard E. (Rik) Faith <faith@valinux.com>
* Gareth Hughes <gareth@valinux.com>
*
*/
#include "drmP.h"
int drm_lock_take(__volatile__ unsigned int *lock, unsigned int context)
{
unsigned int old, new;
do {
old = *lock;
if (old & _DRM_LOCK_HELD) new = old | _DRM_LOCK_CONT;
else new = context | _DRM_LOCK_HELD;
} while (!atomic_cmpset_int(lock, old, new));
if (_DRM_LOCKING_CONTEXT(old) == context) {
if (old & _DRM_LOCK_HELD) {
if (context != DRM_KERNEL_CONTEXT) {
DRM_ERROR("%d holds heavyweight lock\n",
context);
}
return 0;
}
}
if (new == (context | _DRM_LOCK_HELD)) {
/* Have lock */
return 1;
}
return 0;
}
/* This takes a lock forcibly and hands it to context. Should ONLY be used
inside *_unlock to give lock to kernel before calling *_dma_schedule. */
int drm_lock_transfer(drm_device_t *dev,
__volatile__ unsigned int *lock, unsigned int context)
{
unsigned int old, new;
dev->lock.filp = NULL;
do {
old = *lock;
new = context | _DRM_LOCK_HELD;
} while (!atomic_cmpset_int(lock, old, new));
return 1;
}
int drm_lock_free(drm_device_t *dev,
__volatile__ unsigned int *lock, unsigned int context)
{
unsigned int old, new;
dev->lock.filp = NULL;
do {
old = *lock;
new = 0;
} while (!atomic_cmpset_int(lock, old, new));
if (_DRM_LOCK_IS_HELD(old) && _DRM_LOCKING_CONTEXT(old) != context) {
DRM_ERROR("%d freed heavyweight lock held by %d\n",
context, _DRM_LOCKING_CONTEXT(old));
return 1;
}
DRM_WAKEUP_INT((void *)&dev->lock.lock_queue);
return 0;
}
int drm_lock(DRM_IOCTL_ARGS)
{
DRM_DEVICE;
drm_lock_t lock;
int ret = 0;
DRM_COPY_FROM_USER_IOCTL(lock, (drm_lock_t *)data, sizeof(lock));
if (lock.context == DRM_KERNEL_CONTEXT) {
DRM_ERROR("Process %d using kernel context %d\n",
DRM_CURRENTPID, lock.context);
return EINVAL;
}
DRM_DEBUG("%d (pid %d) requests lock (0x%08x), flags = 0x%08x\n",
lock.context, DRM_CURRENTPID, dev->lock.hw_lock->lock, lock.flags);
if (dev->driver.use_dma_queue && lock.context < 0)
return EINVAL;
DRM_LOCK();
for (;;) {
if (drm_lock_take(&dev->lock.hw_lock->lock, lock.context)) {
dev->lock.filp = (void *)(uintptr_t)DRM_CURRENTPID;
dev->lock.lock_time = jiffies;
atomic_inc(&dev->counts[_DRM_STAT_LOCKS]);
break; /* Got lock */
}
/* Contention */
#if defined(__FreeBSD__) && __FreeBSD_version > 500000
ret = msleep((void *)&dev->lock.lock_queue, &dev->dev_lock,
PZERO | PCATCH, "drmlk2", 0);
#else
ret = tsleep((void *)&dev->lock.lock_queue, PZERO | PCATCH,
"drmlk2", 0);
#endif
if (ret != 0)
break;
}
DRM_UNLOCK();
DRM_DEBUG("%d %s\n", lock.context, ret ? "interrupted" : "has lock");
if (ret != 0)
return ret;
/* XXX: Add signal blocking here */
if (dev->driver.dma_quiescent != NULL &&
(lock.flags & _DRM_LOCK_QUIESCENT))
dev->driver.dma_quiescent(dev);
return 0;
}
int drm_unlock(DRM_IOCTL_ARGS)
{
DRM_DEVICE;
drm_lock_t lock;
DRM_COPY_FROM_USER_IOCTL(lock, (drm_lock_t *)data, sizeof(lock));
if (lock.context == DRM_KERNEL_CONTEXT) {
DRM_ERROR("Process %d using kernel context %d\n",
DRM_CURRENTPID, lock.context);
return EINVAL;
}
atomic_inc(&dev->counts[_DRM_STAT_UNLOCKS]);
DRM_LOCK();
drm_lock_transfer(dev, &dev->lock.hw_lock->lock, DRM_KERNEL_CONTEXT);
if (drm_lock_free(dev, &dev->lock.hw_lock->lock, DRM_KERNEL_CONTEXT)) {
DRM_ERROR("\n");
}
DRM_UNLOCK();
return 0;
}
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