diff options
Diffstat (limited to 'linux/lock.c')
| -rw-r--r-- | linux/lock.c | 231 |
1 files changed, 231 insertions, 0 deletions
diff --git a/linux/lock.c b/linux/lock.c new file mode 100644 index 00000000..ab1c0742 --- /dev/null +++ b/linux/lock.c @@ -0,0 +1,231 @@ +/* lock.c -- IOCTLs for locking -*- linux-c -*- + * Created: Tue Feb 2 08:37:54 1999 by faith@precisioninsight.com + * Revised: Tue Oct 12 08:51:06 1999 by faith@precisioninsight.com + * + * Copyright 1999 Precision Insight, Inc., Cedar Park, Texas. + * 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 + * PRECISION INSIGHT 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. + * + * $PI: xc/programs/Xserver/hw/xfree86/os-support/linux/drm/kernel/lock.c,v 1.5 1999/08/30 13:05:00 faith Exp $ + * $XFree86: xc/programs/Xserver/hw/xfree86/os-support/linux/drm/kernel/lock.c,v 1.1 1999/09/25 14:38:01 dawes Exp $ + * + */ + +#define __NO_VERSION__ +#include "drmP.h" + +int drm_block(struct inode *inode, struct file *filp, unsigned int cmd, + unsigned long arg) +{ + DRM_DEBUG("\n"); + return 0; +} + +int drm_unblock(struct inode *inode, struct file *filp, unsigned int cmd, + unsigned long arg) +{ + DRM_DEBUG("\n"); + return 0; +} + +int drm_lock_take(__volatile__ unsigned int *lock, unsigned int context) +{ + unsigned int old; + unsigned int new; + char failed; + + DRM_DEBUG("%d attempts\n", context); + do { + old = *lock; + if (old & _DRM_LOCK_HELD) new = old | _DRM_LOCK_CONT; + else new = context | _DRM_LOCK_HELD; + _DRM_CAS(lock, old, new, failed); + } while (failed); + 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 */ + DRM_DEBUG("%d\n", context); + return 1; + } + DRM_DEBUG("%d unable to get lock held by %d\n", + context, _DRM_LOCKING_CONTEXT(old)); + 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; + unsigned int new; + char failed; + + dev->lock.pid = 0; + do { + old = *lock; + new = context | _DRM_LOCK_HELD; + _DRM_CAS(lock, old, new, failed); + } while (failed); + DRM_DEBUG("%d => %d\n", _DRM_LOCKING_CONTEXT(old), context); + return 1; +} + +int drm_lock_free(drm_device_t *dev, + __volatile__ unsigned int *lock, unsigned int context) +{ + unsigned int old; + unsigned int new; + char failed; + pid_t pid = dev->lock.pid; + + DRM_DEBUG("%d\n", context); + dev->lock.pid = 0; + do { + old = *lock; + new = 0; + _DRM_CAS(lock, old, new, failed); + } while (failed); + if (_DRM_LOCK_IS_HELD(old) && _DRM_LOCKING_CONTEXT(old) != context) { + DRM_ERROR("%d freed heavyweight lock held by %d (pid %d)\n", + context, + _DRM_LOCKING_CONTEXT(old), + pid); + return 1; + } + wake_up_interruptible(&dev->lock.lock_queue); + return 0; +} + +static int drm_flush_queue(drm_device_t *dev, int context) +{ + DECLARE_WAITQUEUE(entry, current); + int ret = 0; + drm_queue_t *q = dev->queuelist[context]; + + DRM_DEBUG("\n"); + + atomic_inc(&q->use_count); + if (atomic_read(&q->use_count) > 1) { + atomic_inc(&q->block_write); + current->state = TASK_INTERRUPTIBLE; + add_wait_queue(&q->flush_queue, &entry); + atomic_inc(&q->block_count); + for (;;) { + if (!DRM_BUFCOUNT(&q->waitlist)) break; + schedule(); + if (signal_pending(current)) { + ret = -EINTR; /* Can't restart */ + break; + } + } + atomic_dec(&q->block_count); + current->state = TASK_RUNNING; + remove_wait_queue(&q->flush_queue, &entry); + } + atomic_dec(&q->use_count); + atomic_inc(&q->total_flushed); + + /* NOTE: block_write is still incremented! + Use drm_flush_unlock_queue to decrement. */ + return ret; +} + +static int drm_flush_unblock_queue(drm_device_t *dev, int context) +{ + drm_queue_t *q = dev->queuelist[context]; + + DRM_DEBUG("\n"); + + atomic_inc(&q->use_count); + if (atomic_read(&q->use_count) > 1) { + if (atomic_read(&q->block_write)) { + atomic_dec(&q->block_write); + wake_up_interruptible(&q->write_queue); + } + } + atomic_dec(&q->use_count); + return 0; +} + +int drm_flush_block_and_flush(drm_device_t *dev, int context, + drm_lock_flags_t flags) +{ + int ret = 0; + int i; + + DRM_DEBUG("\n"); + + if (flags & _DRM_LOCK_FLUSH) { + ret = drm_flush_queue(dev, DRM_KERNEL_CONTEXT); + if (!ret) ret = drm_flush_queue(dev, context); + } + if (flags & _DRM_LOCK_FLUSH_ALL) { + for (i = 0; !ret && i < dev->queue_count; i++) { + ret = drm_flush_queue(dev, i); + } + } + return ret; +} + +int drm_flush_unblock(drm_device_t *dev, int context, drm_lock_flags_t flags) +{ + int ret = 0; + int i; + + DRM_DEBUG("\n"); + + if (flags & _DRM_LOCK_FLUSH) { + ret = drm_flush_unblock_queue(dev, DRM_KERNEL_CONTEXT); + if (!ret) ret = drm_flush_unblock_queue(dev, context); + } + if (flags & _DRM_LOCK_FLUSH_ALL) { + for (i = 0; !ret && i < dev->queue_count; i++) { + ret = drm_flush_unblock_queue(dev, i); + } + } + + return ret; +} + +int drm_finish(struct inode *inode, struct file *filp, unsigned int cmd, + unsigned long arg) +{ + drm_file_t *priv = filp->private_data; + drm_device_t *dev = priv->dev; + int ret = 0; + drm_lock_t lock; + + DRM_DEBUG("\n"); + + copy_from_user_ret(&lock, (drm_lock_t *)arg, sizeof(lock), -EFAULT); + ret = drm_flush_block_and_flush(dev, lock.context, lock.flags); + drm_flush_unblock(dev, lock.context, lock.flags); + return ret; +} |