/*
* Copyright (c) 2006, 2008, Oracle and/or its affiliates. All rights reserved.
*/
/*
* 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(drm_lock_data_t *lock_data, unsigned int context)
{
unsigned int old, new, prev;
volatile unsigned int *lock = &lock_data->hw_lock->lock;
do {
old = *lock;
if (old & _DRM_LOCK_HELD)
new = old | _DRM_LOCK_CONT;
else
new = context | _DRM_LOCK_HELD;
prev = atomic_cas_uint(lock, old, new);
} while (prev != old);
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 ((_DRM_LOCKING_CONTEXT(new)) == context &&
_DRM_LOCK_IS_HELD(new)) {
/* 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, prev;
dev->lock.filp = NULL;
do {
old = *lock;
new = context | _DRM_LOCK_HELD;
prev = atomic_cas_uint(lock, old, new);
} while (prev != old);
return (1);
}
int
drm_lock_free(drm_device_t *dev, volatile unsigned int *lock,
unsigned int context)
{
unsigned int old, new, prev;
mutex_enter(&(dev->lock.lock_mutex));
dev->lock.filp = NULL;
do {
old = *lock;
new = 0;
prev = atomic_cas_uint(lock, old, new);
} while (prev != old);
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));
mutex_exit(&(dev->lock.lock_mutex));
return (1);
}
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);
}