drm_lock.c revision 1450
98N/A/*
98N/A * Copyright (c) 2006, 2008, Oracle and/or its affiliates. All rights reserved.
1351N/A */
98N/A
98N/A/*
919N/A * lock.c -- IOCTLs for locking -*- linux-c -*-
919N/A * Created: Tue Feb 2 08:37:54 1999 by faith@valinux.com
919N/A */
919N/A/*
919N/A * Copyright 1999 Precision Insight, Inc., Cedar Park, Texas.
919N/A * Copyright 2000 VA Linux Systems, Inc., Sunnyvale, California.
919N/A * All Rights Reserved.
919N/A *
919N/A * Permission is hereby granted, free of charge, to any person obtaining a
919N/A * copy of this software and associated documentation files (the "Software"),
919N/A * to deal in the Software without restriction, including without limitation
919N/A * the rights to use, copy, modify, merge, publish, distribute, sublicense,
919N/A * and/or sell copies of the Software, and to permit persons to whom the
919N/A * Software is furnished to do so, subject to the following conditions:
919N/A *
919N/A * The above copyright notice and this permission notice (including the next
919N/A * paragraph) shall be included in all copies or substantial portions of the
98N/A * Software.
98N/A *
493N/A * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
1059N/A * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
98N/A * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
970N/A * VA LINUX SYSTEMS AND/OR ITS SUPPLIERS BE LIABLE FOR ANY CLAIM, DAMAGES OR
970N/A * OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE,
970N/A * ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR
970N/A * OTHER DEALINGS IN THE SOFTWARE.
1360N/A *
1360N/A * Authors:
970N/A * Rickard E. (Rik) Faith <faith@valinux.com>
970N/A * Gareth Hughes <gareth@valinux.com>
970N/A *
970N/A */
970N/A
98N/A#include "drmP.h"
1351N/A
493N/Aint
911N/Adrm_lock_take(drm_lock_data_t *lock_data, unsigned int context)
1351N/A{
1351N/A unsigned int old, new, prev;
98N/A volatile unsigned int *lock = &lock_data->hw_lock->lock;
98N/A
1059N/A do {
156N/A old = *lock;
98N/A if (old & _DRM_LOCK_HELD)
98N/A new = old | _DRM_LOCK_CONT;
1059N/A else
1059N/A new = context | _DRM_LOCK_HELD;
1059N/A prev = atomic_cas_uint(lock, old, new);
98N/A } while (prev != old);
1059N/A
1059N/A if (_DRM_LOCKING_CONTEXT(old) == context) {
1059N/A if (old & _DRM_LOCK_HELD) {
1059N/A if (context != DRM_KERNEL_CONTEXT) {
1059N/A DRM_ERROR("%d holds heavyweight lock\n",
98N/A context);
98N/A }
1097N/A return (0);
493N/A }
1262N/A }
1262N/A if ((_DRM_LOCKING_CONTEXT(new)) == context &&
231N/A _DRM_LOCK_IS_HELD(new)) {
231N/A /* Have lock */
1097N/A return (1);
493N/A }
98N/A return (0);
970N/A}
970N/A
970N/A/*
98N/A * This takes a lock forcibly and hands it to context. Should ONLY be used
493N/A * inside *_unlock to give lock to kernel before calling *_dma_schedule.
98N/A */
98N/Aint
98N/Adrm_lock_transfer(drm_device_t *dev, volatile unsigned int *lock,
98N/A unsigned int context)
851N/A{
1196N/A unsigned int old, new, prev;
659N/A
378N/A dev->lock.filp = NULL;
659N/A do {
378N/A old = *lock;
98N/A new = context | _DRM_LOCK_HELD;
493N/A prev = atomic_cas_uint(lock, old, new);
606N/A } while (prev != old);
606N/A
98N/A return (1);
493N/A}
606N/A
606N/Aint
98N/Adrm_lock_free(drm_device_t *dev, volatile unsigned int *lock,
98N/A unsigned int context)
493N/A{
606N/A unsigned int old, new, prev;
606N/A
98N/A mutex_enter(&(dev->lock.lock_mutex));
98N/A dev->lock.filp = NULL;
1097N/A do {
98N/A old = *lock;
606N/A new = 0;
606N/A prev = atomic_cas_uint(lock, old, new);
1097N/A } while (prev != old);
1097N/A
1262N/A if (_DRM_LOCK_IS_HELD(old) &&
231N/A (_DRM_LOCKING_CONTEXT(old) != context)) {
231N/A DRM_ERROR("%d freed heavyweight lock held by %d\n",
606N/A context, _DRM_LOCKING_CONTEXT(old));
606N/A mutex_exit(&(dev->lock.lock_mutex));
98N/A return (1);
98N/A }
cv_broadcast(&(dev->lock.lock_cv));
mutex_exit(&(dev->lock.lock_mutex));
return (0);
}
/*ARGSUSED*/
int
drm_lock(DRM_IOCTL_ARGS)
{
DRM_DEVICE;
drm_lock_t lock;
int ret = 0;
DRM_COPYFROM_WITH_RETURN(&lock, (void *)data, sizeof (lock));
if (lock.context == DRM_KERNEL_CONTEXT) {
return (EINVAL);
}
if (dev->driver->use_dma_queue && lock.context < 0)
return (EINVAL);
mutex_enter(&(dev->lock.lock_mutex));
for (;;) {
if (drm_lock_take(&dev->lock, lock.context)) {
dev->lock.filp = fpriv;
dev->lock.lock_time = jiffies;
break; /* Got lock */
}
ret = cv_wait_sig(&(dev->lock.lock_cv),
&(dev->lock.lock_mutex));
if (ret == 0) {
mutex_exit(&(dev->lock.lock_mutex));
return (EINTR);
}
}
mutex_exit(&(dev->lock.lock_mutex));
if (dev->driver->dma_quiescent != NULL &&
(lock.flags & _DRM_LOCK_QUIESCENT))
dev->driver->dma_quiescent(dev);
return (0);
}
/*ARGSUSED*/
int
drm_unlock(DRM_IOCTL_ARGS)
{
DRM_DEVICE;
drm_lock_t lock;
DRM_COPYFROM_WITH_RETURN(&lock, (void *)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_32(&dev->counts[_DRM_STAT_UNLOCKS]);
DRM_LOCK();
if (drm_lock_free(dev, &dev->lock.hw_lock->lock, lock.context)) {
DRM_ERROR("drm_unlock\n");
}
DRM_UNLOCK();
return (0);
}