From d817cc1f30060fcc4a85a05b2de8a2a1687421b5 Mon Sep 17 00:00:00 2001 From: =?UTF-8?q?Michel=20D=C3=A4nzer?= Date: Wed, 16 Aug 2006 15:47:22 +0200 Subject: Add support for interrupt triggered driver callback with lock held to DRM core. --- linux-core/drm_irq.c | 74 ++++++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 74 insertions(+) (limited to 'linux-core/drm_irq.c') diff --git a/linux-core/drm_irq.c b/linux-core/drm_irq.c index d4e5fbd5..b57fffb0 100644 --- a/linux-core/drm_irq.c +++ b/linux-core/drm_irq.c @@ -118,6 +118,7 @@ static int drm_irq_install(drm_device_t * dev) init_waitqueue_head(&dev->vbl_queue); spin_lock_init(&dev->vbl_lock); + spin_lock_init(&dev->tasklet_lock); INIT_LIST_HEAD(&dev->vbl_sigs.head); INIT_LIST_HEAD(&dev->vbl_sigs2.head); @@ -396,3 +397,76 @@ void drm_vbl_send_signals(drm_device_t * dev) spin_unlock_irqrestore(&dev->vbl_lock, flags); } EXPORT_SYMBOL(drm_vbl_send_signals); + +/** + * Tasklet wrapper function. + * + * \param data DRM device in disguise. + * + * Attempts to grab the HW lock and calls the driver callback on success. On + * failure, leave the lock marked as contended so the callback can be called + * from drm_unlock(). + */ +static void drm_locked_tasklet_func(unsigned long data) +{ + drm_device_t *dev = (drm_device_t*)data; + unsigned int irqflags; + + spin_lock_irqsave(&dev->tasklet_lock, irqflags); + + if (!dev->locked_tasklet_func || + !drm_lock_take(&dev->lock.hw_lock->lock, + DRM_KERNEL_CONTEXT)) { + spin_unlock_irqrestore(&dev->tasklet_lock, irqflags); + return; + } + + dev->lock.lock_time = jiffies; + atomic_inc(&dev->counts[_DRM_STAT_LOCKS]); + + dev->locked_tasklet_func(dev); + + drm_lock_free(dev, &dev->lock.hw_lock->lock, + DRM_KERNEL_CONTEXT); + + dev->locked_tasklet_func = NULL; + + spin_unlock_irqrestore(&dev->tasklet_lock, irqflags); +} + +/** + * Schedule a tasklet to call back a driver hook with the HW lock held. + * + * \param dev DRM device. + * \param func Driver callback. + * + * This is intended for triggering actions that require the HW lock from an + * interrupt handler. The lock will be grabbed ASAP after the interrupt handler + * completes. Note that the callback may be called from interrupt or process + * context, it must not make any assumptions about this. Also, the HW lock will + * be held with the kernel context or any client context. + */ +void drm_locked_tasklet(drm_device_t *dev, void (*func)(drm_device_t*)) +{ + unsigned int irqflags; + static DECLARE_TASKLET(drm_tasklet, drm_locked_tasklet_func, 0); + + if (test_bit(TASKLET_STATE_SCHED, &drm_tasklet.state)) + return; + + spin_lock_irqsave(&dev->tasklet_lock, irqflags); + + if (dev->locked_tasklet_func) { + spin_unlock_irqrestore(&dev->tasklet_lock, irqflags); + return; + } + + dev->locked_tasklet_func = func; + + spin_unlock_irqrestore(&dev->tasklet_lock, irqflags); + + drm_tasklet.data = (unsigned long)dev; + + tasklet_hi_schedule(&drm_tasklet); +} +EXPORT_SYMBOL(drm_locked_tasklet); -- cgit v1.2.3