drm: Add support for interrupt triggered driver callback with lock held to DRM core. (2e54a007) · Commits · e / devices / android_kernel_fairphone_FP4

drivers/char/drm/drmP.h

+3 −0

Original line number	Diff line number	Diff line
		@@ -715,6 +715,8 @@ typedef struct drm_device {
		drm_vbl_sig_t vbl_sigs; /*< signal list to send on VBLANK /
		drm_vbl_sig_t vbl_sigs2; /*< signals to send on secondary VBLANK /
		unsigned int vbl_pending;
		spinlock_t tasklet_lock; /*< For drm_locked_tasklet /
		void (locked_tasklet_func)(struct drm_device dev);

		/@} /
		cycles_t ctx_start;
		@@ -966,6 +968,7 @@ extern int drm_wait_vblank(struct inode inode, struct file filp,
		unsigned int cmd, unsigned long arg);
		extern int drm_vblank_wait(drm_device_t * dev, unsigned int *vbl_seq);
		extern void drm_vbl_send_signals(drm_device_t * dev);
		extern void drm_locked_tasklet(drm_device_t dev, void(func)(drm_device_t*));

		/* AGP/GART support (drm_agpsupport.h) */
		extern drm_agp_head_t drm_agp_init(drm_device_t dev);

drivers/char/drm/drm_irq.c

+76 −0

Original line number	Diff line number	Diff line
		@@ -119,6 +119,7 @@ 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);
		@@ -176,6 +177,8 @@ int drm_irq_uninstall(drm_device_t * dev)

		free_irq(dev->irq, dev);

		dev->locked_tasklet_func = NULL;

		return 0;
		}

		@@ -399,3 +402,76 @@ void drm_vbl_send_signals(drm_device_t * dev)
		}

		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 long 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 long 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);

drivers/char/drm/drm_lock.c

+11 −0

Original line number	Diff line number	Diff line
		@@ -155,6 +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 int irqflags;

		if (copy_from_user(&lock, (drm_lock_t __user *) arg, sizeof(lock)))
		return -EFAULT;
		@@ -165,6 +166,16 @@ 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