X-Git-Url: http://pilppa.org/gitweb/gitweb.cgi?a=blobdiff_plain;f=drivers%2Fchar%2Fdrm%2Fdrm_lock.c;h=befd1af19dfe0962ff7915c7cd0e1573bf7270e6;hb=9462544fdfe06c1d0d535876fedb4b886c861c73;hp=b48a595d54eca0e9c13b0cb269b88fba6dc49f56;hpb=a880b11a95fab4618da412d99fc7365d723e702d;p=linux-2.6-omap-h63xx.git diff --git a/drivers/char/drm/drm_lock.c b/drivers/char/drm/drm_lock.c index b48a595d54e..befd1af19df 100644 --- a/drivers/char/drm/drm_lock.c +++ b/drivers/char/drm/drm_lock.c @@ -35,9 +35,6 @@ #include "drmP.h" -static int drm_lock_transfer(drm_device_t * dev, - __volatile__ unsigned int *lock, - unsigned int context); static int drm_notifier(void *priv); /** @@ -80,6 +77,9 @@ int drm_lock(struct inode *inode, struct file *filp, return -EINVAL; add_wait_queue(&dev->lock.lock_queue, &entry); + spin_lock(&dev->lock.spinlock); + dev->lock.user_waiters++; + spin_unlock(&dev->lock.spinlock); for (;;) { __set_current_state(TASK_INTERRUPTIBLE); if (!dev->lock.hw_lock) { @@ -87,7 +87,7 @@ int drm_lock(struct inode *inode, struct file *filp, ret = -EINTR; break; } - if (drm_lock_take(&dev->lock.hw_lock->lock, lock.context)) { + if (drm_lock_take(&dev->lock, lock.context)) { dev->lock.filp = filp; dev->lock.lock_time = jiffies; atomic_inc(&dev->counts[_DRM_STAT_LOCKS]); @@ -101,12 +101,14 @@ int drm_lock(struct inode *inode, struct file *filp, break; } } + spin_lock(&dev->lock.spinlock); + dev->lock.user_waiters--; + spin_unlock(&dev->lock.spinlock); __set_current_state(TASK_RUNNING); remove_wait_queue(&dev->lock.lock_queue, &entry); - DRM_DEBUG("%d %s\n", lock.context, ret ? "interrupted" : "has lock"); - if (ret) - return ret; + DRM_DEBUG( "%d %s\n", lock.context, ret ? "interrupted" : "has lock" ); + if (ret) return ret; sigemptyset(&dev->sigmask); sigaddset(&dev->sigmask, SIGSTOP); @@ -127,15 +129,12 @@ int drm_lock(struct inode *inode, struct file *filp, } } - /* dev->driver->kernel_context_switch isn't used by any of the x86 - * drivers but is used by the Sparc driver. - */ - if (dev->driver->kernel_context_switch && dev->last_context != lock.context) { dev->driver->kernel_context_switch(dev, dev->last_context, lock.context); } + return 0; } @@ -156,6 +155,7 @@ int drm_unlock(struct inode *inode, struct file *filp, drm_file_t *priv = filp->private_data; drm_device_t *dev = priv->head->dev; drm_lock_t lock; + unsigned long irqflags; if (copy_from_user(&lock, (drm_lock_t __user *) arg, sizeof(lock))) return -EFAULT; @@ -166,20 +166,26 @@ int drm_unlock(struct inode *inode, struct file *filp, return -EINVAL; } + spin_lock_irqsave(&dev->tasklet_lock, irqflags); + + if (dev->locked_tasklet_func) { + dev->locked_tasklet_func(dev); + + dev->locked_tasklet_func = NULL; + } + + spin_unlock_irqrestore(&dev->tasklet_lock, irqflags); + atomic_inc(&dev->counts[_DRM_STAT_UNLOCKS]); /* kernel_context_switch isn't used by any of the x86 drm * modules but is required by the Sparc driver. */ if (dev->driver->kernel_context_switch_unlock) - dev->driver->kernel_context_switch_unlock(dev, &lock); + dev->driver->kernel_context_switch_unlock(dev); else { - 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"); + if (drm_lock_free(&dev->lock,lock.context)) { + /* FIXME: Should really bail out here. */ } } @@ -196,18 +202,26 @@ int drm_unlock(struct inode *inode, struct file *filp, * * Attempt to mark the lock as held by the given context, via the \p cmpxchg instruction. */ -int drm_lock_take(__volatile__ unsigned int *lock, unsigned int context) +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; + spin_lock(&lock_data->spinlock); do { old = *lock; if (old & _DRM_LOCK_HELD) new = old | _DRM_LOCK_CONT; - else - new = context | _DRM_LOCK_HELD; + else { + new = context | _DRM_LOCK_HELD | + ((lock_data->user_waiters + lock_data->kernel_waiters > 1) ? + _DRM_LOCK_CONT : 0); + } prev = cmpxchg(lock, old, new); } while (prev != old); + spin_unlock(&lock_data->spinlock); + if (_DRM_LOCKING_CONTEXT(old) == context) { if (old & _DRM_LOCK_HELD) { if (context != DRM_KERNEL_CONTEXT) { @@ -217,7 +231,8 @@ int drm_lock_take(__volatile__ unsigned int *lock, unsigned int context) return 0; } } - if (new == (context | _DRM_LOCK_HELD)) { + + if ((_DRM_LOCKING_CONTEXT(new)) == context && (new & _DRM_LOCK_HELD)) { /* Have lock */ return 1; } @@ -236,13 +251,13 @@ int drm_lock_take(__volatile__ unsigned int *lock, unsigned int context) * Resets the lock file pointer. * Marks the lock as held by the given context, via the \p cmpxchg instruction. */ -static int drm_lock_transfer(drm_device_t * dev, - __volatile__ unsigned int *lock, +static int drm_lock_transfer(drm_lock_data_t *lock_data, unsigned int context) { unsigned int old, new, prev; + volatile unsigned int *lock = &lock_data->hw_lock->lock; - dev->lock.filp = NULL; + lock_data->filp = NULL; do { old = *lock; new = context | _DRM_LOCK_HELD; @@ -262,23 +277,32 @@ static int drm_lock_transfer(drm_device_t * dev, * Marks the lock as not held, via the \p cmpxchg instruction. Wakes any task * waiting on the lock queue. */ -int drm_lock_free(drm_device_t * dev, - __volatile__ unsigned int *lock, unsigned int context) +int drm_lock_free(drm_lock_data_t *lock_data, unsigned int context) { unsigned int old, new, prev; + volatile unsigned int *lock = &lock_data->hw_lock->lock; + + spin_lock(&lock_data->spinlock); + if (lock_data->kernel_waiters != 0) { + drm_lock_transfer(lock_data, 0); + lock_data->idle_has_lock = 1; + spin_unlock(&lock_data->spinlock); + return 1; + } + spin_unlock(&lock_data->spinlock); - dev->lock.filp = NULL; do { old = *lock; - new = 0; + new = _DRM_LOCKING_CONTEXT(old); prev = cmpxchg(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)); return 1; } - wake_up_interruptible(&dev->lock.lock_queue); + wake_up_interruptible(&lock_data->lock_queue); return 0; } @@ -312,3 +336,67 @@ static int drm_notifier(void *priv) } while (prev != old); return 0; } + +/** + * This function returns immediately and takes the hw lock + * with the kernel context if it is free, otherwise it gets the highest priority when and if + * it is eventually released. + * + * This guarantees that the kernel will _eventually_ have the lock _unless_ it is held + * by a blocked process. (In the latter case an explicit wait for the hardware lock would cause + * a deadlock, which is why the "idlelock" was invented). + * + * This should be sufficient to wait for GPU idle without + * having to worry about starvation. + */ + +void drm_idlelock_take(drm_lock_data_t *lock_data) +{ + int ret = 0; + + spin_lock(&lock_data->spinlock); + lock_data->kernel_waiters++; + if (!lock_data->idle_has_lock) { + + spin_unlock(&lock_data->spinlock); + ret = drm_lock_take(lock_data, DRM_KERNEL_CONTEXT); + spin_lock(&lock_data->spinlock); + + if (ret == 1) + lock_data->idle_has_lock = 1; + } + spin_unlock(&lock_data->spinlock); +} +EXPORT_SYMBOL(drm_idlelock_take); + +void drm_idlelock_release(drm_lock_data_t *lock_data) +{ + unsigned int old, prev; + volatile unsigned int *lock = &lock_data->hw_lock->lock; + + spin_lock(&lock_data->spinlock); + if (--lock_data->kernel_waiters == 0) { + if (lock_data->idle_has_lock) { + do { + old = *lock; + prev = cmpxchg(lock, old, DRM_KERNEL_CONTEXT); + } while (prev != old); + wake_up_interruptible(&lock_data->lock_queue); + lock_data->idle_has_lock = 0; + } + } + spin_unlock(&lock_data->spinlock); +} +EXPORT_SYMBOL(drm_idlelock_release); + + +int drm_i_have_hw_lock(struct file *filp) +{ + DRM_DEVICE; + + return (priv->lock_count && dev->lock.hw_lock && + _DRM_LOCK_IS_HELD(dev->lock.hw_lock->lock) && + dev->lock.filp == filp); +} + +EXPORT_SYMBOL(drm_i_have_hw_lock);