drivers/gpu/drm/vmwgfx/vmwgfx_irq.c - third_party/linux - Git at Google

 /**************************************************************************
  *
  * Copyright © 2009-2015 VMware, Inc., Palo Alto, CA., USA
  * 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, sub license, 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 NON-INFRINGEMENT. IN NO EVENT SHALL
  * THE COPYRIGHT HOLDERS, AUTHORS 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.
  *
  **************************************************************************/

 #include <drm/drmP.h>
 #include "vmwgfx_drv.h"

 #define VMW_FENCE_WRAP (1 << 24)

 /**
  * vmw_thread_fn - Deferred (process context) irq handler
  *
  * @irq: irq number
  * @arg: Closure argument. Pointer to a struct drm_device cast to void *
  *
  * This function implements the deferred part of irq processing.
  * The function is guaranteed to run at least once after the
  * vmw_irq_handler has returned with IRQ_WAKE_THREAD.
  *
  */
 static irqreturn_t vmw_thread_fn(int irq, void *arg)
 {
 	struct drm_device *dev = (struct drm_device *)arg;
 	struct vmw_private *dev_priv = vmw_priv(dev);
 	irqreturn_t ret = IRQ_NONE;

 	if (test_and_clear_bit(VMW_IRQTHREAD_FENCE,
 			       dev_priv->irqthread_pending)) {
 		vmw_fences_update(dev_priv->fman);
 		wake_up_all(&dev_priv->fence_queue);
 		ret = IRQ_HANDLED;
 	}

 	if (test_and_clear_bit(VMW_IRQTHREAD_CMDBUF,
 			       dev_priv->irqthread_pending)) {
 		vmw_cmdbuf_irqthread(dev_priv->cman);
 		ret = IRQ_HANDLED;
 	}

 	return ret;
 }

 /**
  * vmw_irq_handler irq handler
  *
  * @irq: irq number
  * @arg: Closure argument. Pointer to a struct drm_device cast to void *
  *
  * This function implements the quick part of irq processing.
  * The function performs fast actions like clearing the device interrupt
  * flags and also reasonably quick actions like waking processes waiting for
  * FIFO space. Other IRQ actions are deferred to the IRQ thread.
  */
 static irqreturn_t vmw_irq_handler(int irq, void *arg)
 {
 	struct drm_device *dev = (struct drm_device *)arg;
 	struct vmw_private *dev_priv = vmw_priv(dev);
 	uint32_t status, masked_status;
 	irqreturn_t ret = IRQ_HANDLED;

 	status = inl(dev_priv->io_start + VMWGFX_IRQSTATUS_PORT);
 	masked_status = status & READ_ONCE(dev_priv->irq_mask);

 	if (likely(status))
 		outl(status, dev_priv->io_start + VMWGFX_IRQSTATUS_PORT);

 	if (!status)
 		return IRQ_NONE;

 	if (masked_status & SVGA_IRQFLAG_FIFO_PROGRESS)
 		wake_up_all(&dev_priv->fifo_queue);

 	if ((masked_status & (SVGA_IRQFLAG_ANY_FENCE |
 			      SVGA_IRQFLAG_FENCE_GOAL)) &&
 	    !test_and_set_bit(VMW_IRQTHREAD_FENCE, dev_priv->irqthread_pending))
 		ret = IRQ_WAKE_THREAD;

 	if ((masked_status & (SVGA_IRQFLAG_COMMAND_BUFFER |
 			      SVGA_IRQFLAG_ERROR)) &&
 	    !test_and_set_bit(VMW_IRQTHREAD_CMDBUF,
 			      dev_priv->irqthread_pending))
 		ret = IRQ_WAKE_THREAD;

 	return ret;
 }

 static bool vmw_fifo_idle(struct vmw_private *dev_priv, uint32_t seqno)
 {

 	return (vmw_read(dev_priv, SVGA_REG_BUSY) == 0);
 }

 void vmw_update_seqno(struct vmw_private *dev_priv,
 			 struct vmw_fifo_state *fifo_state)
 {
 	u32 *fifo_mem = dev_priv->mmio_virt;
 	uint32_t seqno = vmw_mmio_read(fifo_mem + SVGA_FIFO_FENCE);

 	if (dev_priv->last_read_seqno != seqno) {
 		dev_priv->last_read_seqno = seqno;
 		vmw_marker_pull(&fifo_state->marker_queue, seqno);
 		vmw_fences_update(dev_priv->fman);
 	}
 }

 bool vmw_seqno_passed(struct vmw_private *dev_priv,
 			 uint32_t seqno)
 {
 	struct vmw_fifo_state *fifo_state;
 	bool ret;

 	if (likely(dev_priv->last_read_seqno - seqno < VMW_FENCE_WRAP))
 		return true;

 	fifo_state = &dev_priv->fifo;
 	vmw_update_seqno(dev_priv, fifo_state);
 	if (likely(dev_priv->last_read_seqno - seqno < VMW_FENCE_WRAP))
 		return true;

 	if (!(fifo_state->capabilities & SVGA_FIFO_CAP_FENCE) &&
 	    vmw_fifo_idle(dev_priv, seqno))
 		return true;

 	/**
 	 * Then check if the seqno is higher than what we've actually
 	 * emitted. Then the fence is stale and signaled.
 	 */

 	ret = ((atomic_read(&dev_priv->marker_seq) - seqno)
 	       > VMW_FENCE_WRAP);

 	return ret;
 }

 int vmw_fallback_wait(struct vmw_private *dev_priv,
 		      bool lazy,
 		      bool fifo_idle,
 		      uint32_t seqno,
 		      bool interruptible,
 		      unsigned long timeout)
 {
 	struct vmw_fifo_state *fifo_state = &dev_priv->fifo;

 	uint32_t count = 0;
 	uint32_t signal_seq;
 	int ret;
 	unsigned long end_jiffies = jiffies + timeout;
 	bool (*wait_condition)(struct vmw_private *, uint32_t);
 	DEFINE_WAIT(__wait);

 	wait_condition = (fifo_idle) ? &vmw_fifo_idle :
 		&vmw_seqno_passed;

 	/**
 	 * Block command submission while waiting for idle.
 	 */

 	if (fifo_idle) {
 		down_read(&fifo_state->rwsem);
 		if (dev_priv->cman) {
 			ret = vmw_cmdbuf_idle(dev_priv->cman, interruptible,
 					      10*HZ);
 			if (ret)
 				goto out_err;
 		}
 	}

 	signal_seq = atomic_read(&dev_priv->marker_seq);
 	ret = 0;

 	for (;;) {
 		prepare_to_wait(&dev_priv->fence_queue, &__wait,
 				(interruptible) ?
 				TASK_INTERRUPTIBLE : TASK_UNINTERRUPTIBLE);
 		if (wait_condition(dev_priv, seqno))
 			break;
 		if (time_after_eq(jiffies, end_jiffies)) {
 			DRM_ERROR("SVGA device lockup.\n");
 			break;
 		}
 		if (lazy)
 			schedule_timeout(1);
 		else if ((++count & 0x0F) == 0) {
 			/**
 			 * FIXME: Use schedule_hr_timeout here for
 			 * newer kernels and lower CPU utilization.
 			 */

 			__set_current_state(TASK_RUNNING);
 			schedule();
 			__set_current_state((interruptible) ?
 					    TASK_INTERRUPTIBLE :
 					    TASK_UNINTERRUPTIBLE);
 		}
 		if (interruptible && signal_pending(current)) {
 			ret = -ERESTARTSYS;
 			break;
 		}
 	}
 	finish_wait(&dev_priv->fence_queue, &__wait);
 	if (ret == 0 && fifo_idle) {
 		u32 *fifo_mem = dev_priv->mmio_virt;

 		vmw_mmio_write(signal_seq, fifo_mem + SVGA_FIFO_FENCE);
 	}
 	wake_up_all(&dev_priv->fence_queue);
 out_err:
 	if (fifo_idle)
 		up_read(&fifo_state->rwsem);

 	return ret;
 }

 void vmw_generic_waiter_add(struct vmw_private *dev_priv,
 			    u32 flag, int *waiter_count)
 {
 	spin_lock_bh(&dev_priv->waiter_lock);
 	if ((*waiter_count)++ == 0) {
 		outl(flag, dev_priv->io_start + VMWGFX_IRQSTATUS_PORT);
 		dev_priv->irq_mask |= flag;
 		vmw_write(dev_priv, SVGA_REG_IRQMASK, dev_priv->irq_mask);
 	}
 	spin_unlock_bh(&dev_priv->waiter_lock);
 }

 void vmw_generic_waiter_remove(struct vmw_private *dev_priv,
 			       u32 flag, int *waiter_count)
 {
 	spin_lock_bh(&dev_priv->waiter_lock);
 	if (--(*waiter_count) == 0) {
 		dev_priv->irq_mask &= ~flag;
 		vmw_write(dev_priv, SVGA_REG_IRQMASK, dev_priv->irq_mask);
 	}
 	spin_unlock_bh(&dev_priv->waiter_lock);
 }

 void vmw_seqno_waiter_add(struct vmw_private *dev_priv)
 {
 	vmw_generic_waiter_add(dev_priv, SVGA_IRQFLAG_ANY_FENCE,
 			       &dev_priv->fence_queue_waiters);
 }

 void vmw_seqno_waiter_remove(struct vmw_private *dev_priv)
 {
 	vmw_generic_waiter_remove(dev_priv, SVGA_IRQFLAG_ANY_FENCE,
 				  &dev_priv->fence_queue_waiters);
 }

 void vmw_goal_waiter_add(struct vmw_private *dev_priv)
 {
 	vmw_generic_waiter_add(dev_priv, SVGA_IRQFLAG_FENCE_GOAL,
 			       &dev_priv->goal_queue_waiters);
 }

 void vmw_goal_waiter_remove(struct vmw_private *dev_priv)
 {
 	vmw_generic_waiter_remove(dev_priv, SVGA_IRQFLAG_FENCE_GOAL,
 				  &dev_priv->goal_queue_waiters);
 }

 int vmw_wait_seqno(struct vmw_private *dev_priv,
 		      bool lazy, uint32_t seqno,
 		      bool interruptible, unsigned long timeout)
 {
 	long ret;
 	struct vmw_fifo_state *fifo = &dev_priv->fifo;

 	if (likely(dev_priv->last_read_seqno - seqno < VMW_FENCE_WRAP))
 		return 0;

 	if (likely(vmw_seqno_passed(dev_priv, seqno)))
 		return 0;

 	vmw_fifo_ping_host(dev_priv, SVGA_SYNC_GENERIC);

 	if (!(fifo->capabilities & SVGA_FIFO_CAP_FENCE))
 		return vmw_fallback_wait(dev_priv, lazy, true, seqno,
 					 interruptible, timeout);

 	if (!(dev_priv->capabilities & SVGA_CAP_IRQMASK))
 		return vmw_fallback_wait(dev_priv, lazy, false, seqno,
 					 interruptible, timeout);

 	vmw_seqno_waiter_add(dev_priv);

 	if (interruptible)
 		ret = wait_event_interruptible_timeout
 		    (dev_priv->fence_queue,
 		     vmw_seqno_passed(dev_priv, seqno),
 		     timeout);
 	else
 		ret = wait_event_timeout
 		    (dev_priv->fence_queue,
 		     vmw_seqno_passed(dev_priv, seqno),
 		     timeout);

 	vmw_seqno_waiter_remove(dev_priv);

 	if (unlikely(ret == 0))
 		ret = -EBUSY;
 	else if (likely(ret > 0))
 		ret = 0;

 	return ret;
 }

 static void vmw_irq_preinstall(struct drm_device *dev)
 {
 	struct vmw_private *dev_priv = vmw_priv(dev);
 	uint32_t status;

 	status = inl(dev_priv->io_start + VMWGFX_IRQSTATUS_PORT);
 	outl(status, dev_priv->io_start + VMWGFX_IRQSTATUS_PORT);
 }

 void vmw_irq_uninstall(struct drm_device *dev)
 {
 	struct vmw_private *dev_priv = vmw_priv(dev);
 	uint32_t status;

 	if (!(dev_priv->capabilities & SVGA_CAP_IRQMASK))
 		return;

 	if (!dev->irq_enabled)
 		return;

 	vmw_write(dev_priv, SVGA_REG_IRQMASK, 0);

 	status = inl(dev_priv->io_start + VMWGFX_IRQSTATUS_PORT);
 	outl(status, dev_priv->io_start + VMWGFX_IRQSTATUS_PORT);

 	dev->irq_enabled = false;
 	free_irq(dev->irq, dev);
 }

 /**
  * vmw_irq_install - Install the irq handlers
  *
  * @dev:  Pointer to the drm device.
  * @irq:  The irq number.
  * Return:  Zero if successful. Negative number otherwise.
  */
 int vmw_irq_install(struct drm_device *dev, int irq)
 {
 	int ret;

 	if (dev->irq_enabled)
 		return -EBUSY;

 	vmw_irq_preinstall(dev);

 	ret = request_threaded_irq(irq, vmw_irq_handler, vmw_thread_fn,
 				   IRQF_SHARED, VMWGFX_DRIVER_NAME, dev);
 	if (ret < 0)
 		return ret;

 	dev->irq_enabled = true;
 	dev->irq = irq;

 	return ret;
 }
	/**************************************************************************
	*
	* Copyright © 2009-2015 VMware, Inc., Palo Alto, CA., USA
	* 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, sub license, 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 NON-INFRINGEMENT. IN NO EVENT SHALL
	* THE COPYRIGHT HOLDERS, AUTHORS 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.
	*
	**************************************************************************/

	#include <drm/drmP.h>
	#include "vmwgfx_drv.h"

	#define VMW_FENCE_WRAP (1 << 24)

	/**
	* vmw_thread_fn - Deferred (process context) irq handler
	*
	* @irq: irq number
	* @arg: Closure argument. Pointer to a struct drm_device cast to void *
	*
	* This function implements the deferred part of irq processing.
	* The function is guaranteed to run at least once after the
	* vmw_irq_handler has returned with IRQ_WAKE_THREAD.
	*
	*/
	static irqreturn_t vmw_thread_fn(int irq, void *arg)
	{
	struct drm_device dev = (struct drm_device )arg;
	struct vmw_private *dev_priv = vmw_priv(dev);
	irqreturn_t ret = IRQ_NONE;

	if (test_and_clear_bit(VMW_IRQTHREAD_FENCE,
	dev_priv->irqthread_pending)) {
	vmw_fences_update(dev_priv->fman);
	wake_up_all(&dev_priv->fence_queue);
	ret = IRQ_HANDLED;
	}

	if (test_and_clear_bit(VMW_IRQTHREAD_CMDBUF,
	dev_priv->irqthread_pending)) {
	vmw_cmdbuf_irqthread(dev_priv->cman);
	ret = IRQ_HANDLED;
	}

	return ret;
	}

	/**
	* vmw_irq_handler irq handler
	*
	* @irq: irq number
	* @arg: Closure argument. Pointer to a struct drm_device cast to void *
	*
	* This function implements the quick part of irq processing.
	* The function performs fast actions like clearing the device interrupt
	* flags and also reasonably quick actions like waking processes waiting for
	* FIFO space. Other IRQ actions are deferred to the IRQ thread.
	*/
	static irqreturn_t vmw_irq_handler(int irq, void *arg)
	{
	struct drm_device dev = (struct drm_device )arg;
	struct vmw_private *dev_priv = vmw_priv(dev);
	uint32_t status, masked_status;
	irqreturn_t ret = IRQ_HANDLED;

	status = inl(dev_priv->io_start + VMWGFX_IRQSTATUS_PORT);
	masked_status = status & READ_ONCE(dev_priv->irq_mask);

	if (likely(status))
	outl(status, dev_priv->io_start + VMWGFX_IRQSTATUS_PORT);

	if (!status)
	return IRQ_NONE;

	if (masked_status & SVGA_IRQFLAG_FIFO_PROGRESS)
	wake_up_all(&dev_priv->fifo_queue);

	if ((masked_status & (SVGA_IRQFLAG_ANY_FENCE \|
	SVGA_IRQFLAG_FENCE_GOAL)) &&
	!test_and_set_bit(VMW_IRQTHREAD_FENCE, dev_priv->irqthread_pending))
	ret = IRQ_WAKE_THREAD;

	if ((masked_status & (SVGA_IRQFLAG_COMMAND_BUFFER \|
	SVGA_IRQFLAG_ERROR)) &&
	!test_and_set_bit(VMW_IRQTHREAD_CMDBUF,
	dev_priv->irqthread_pending))
	ret = IRQ_WAKE_THREAD;

	return ret;
	}

	static bool vmw_fifo_idle(struct vmw_private *dev_priv, uint32_t seqno)
	{

	return (vmw_read(dev_priv, SVGA_REG_BUSY) == 0);
	}

	void vmw_update_seqno(struct vmw_private *dev_priv,
	struct vmw_fifo_state *fifo_state)
	{
	u32 *fifo_mem = dev_priv->mmio_virt;
	uint32_t seqno = vmw_mmio_read(fifo_mem + SVGA_FIFO_FENCE);

	if (dev_priv->last_read_seqno != seqno) {
	dev_priv->last_read_seqno = seqno;
	vmw_marker_pull(&fifo_state->marker_queue, seqno);
	vmw_fences_update(dev_priv->fman);
	}
	}

	bool vmw_seqno_passed(struct vmw_private *dev_priv,
	uint32_t seqno)
	{
	struct vmw_fifo_state *fifo_state;
	bool ret;

	if (likely(dev_priv->last_read_seqno - seqno < VMW_FENCE_WRAP))
	return true;

	fifo_state = &dev_priv->fifo;
	vmw_update_seqno(dev_priv, fifo_state);
	if (likely(dev_priv->last_read_seqno - seqno < VMW_FENCE_WRAP))
	return true;

	if (!(fifo_state->capabilities & SVGA_FIFO_CAP_FENCE) &&
	vmw_fifo_idle(dev_priv, seqno))
	return true;

	/**
	* Then check if the seqno is higher than what we've actually
	* emitted. Then the fence is stale and signaled.
	*/

	ret = ((atomic_read(&dev_priv->marker_seq) - seqno)
	> VMW_FENCE_WRAP);

	return ret;
	}

	int vmw_fallback_wait(struct vmw_private *dev_priv,
	bool lazy,
	bool fifo_idle,
	uint32_t seqno,
	bool interruptible,
	unsigned long timeout)
	{
	struct vmw_fifo_state *fifo_state = &dev_priv->fifo;

	uint32_t count = 0;
	uint32_t signal_seq;
	int ret;
	unsigned long end_jiffies = jiffies + timeout;
	bool (wait_condition)(struct vmw_private , uint32_t);
	DEFINE_WAIT(__wait);

	wait_condition = (fifo_idle) ? &vmw_fifo_idle :
	&vmw_seqno_passed;

	/**
	* Block command submission while waiting for idle.
	*/

	if (fifo_idle) {
	down_read(&fifo_state->rwsem);
	if (dev_priv->cman) {
	ret = vmw_cmdbuf_idle(dev_priv->cman, interruptible,
	10*HZ);
	if (ret)
	goto out_err;
	}
	}

	signal_seq = atomic_read(&dev_priv->marker_seq);
	ret = 0;

	for (;;) {
	prepare_to_wait(&dev_priv->fence_queue, &__wait,
	(interruptible) ?
	TASK_INTERRUPTIBLE : TASK_UNINTERRUPTIBLE);
	if (wait_condition(dev_priv, seqno))
	break;
	if (time_after_eq(jiffies, end_jiffies)) {
	DRM_ERROR("SVGA device lockup.\n");
	break;
	}
	if (lazy)
	schedule_timeout(1);
	else if ((++count & 0x0F) == 0) {
	/**
	* FIXME: Use schedule_hr_timeout here for
	* newer kernels and lower CPU utilization.
	*/

	__set_current_state(TASK_RUNNING);
	schedule();
	__set_current_state((interruptible) ?
	TASK_INTERRUPTIBLE :
	TASK_UNINTERRUPTIBLE);
	}
	if (interruptible && signal_pending(current)) {
	ret = -ERESTARTSYS;
	break;
	}
	}
	finish_wait(&dev_priv->fence_queue, &__wait);
	if (ret == 0 && fifo_idle) {
	u32 *fifo_mem = dev_priv->mmio_virt;

	vmw_mmio_write(signal_seq, fifo_mem + SVGA_FIFO_FENCE);
	}
	wake_up_all(&dev_priv->fence_queue);
	out_err:
	if (fifo_idle)
	up_read(&fifo_state->rwsem);

	return ret;
	}

	void vmw_generic_waiter_add(struct vmw_private *dev_priv,
	u32 flag, int *waiter_count)
	{
	spin_lock_bh(&dev_priv->waiter_lock);
	if ((*waiter_count)++ == 0) {
	outl(flag, dev_priv->io_start + VMWGFX_IRQSTATUS_PORT);
	dev_priv->irq_mask \|= flag;
	vmw_write(dev_priv, SVGA_REG_IRQMASK, dev_priv->irq_mask);
	}
	spin_unlock_bh(&dev_priv->waiter_lock);
	}

	void vmw_generic_waiter_remove(struct vmw_private *dev_priv,
	u32 flag, int *waiter_count)
	{
	spin_lock_bh(&dev_priv->waiter_lock);
	if (--(*waiter_count) == 0) {
	dev_priv->irq_mask &= ~flag;
	vmw_write(dev_priv, SVGA_REG_IRQMASK, dev_priv->irq_mask);
	}
	spin_unlock_bh(&dev_priv->waiter_lock);
	}

	void vmw_seqno_waiter_add(struct vmw_private *dev_priv)
	{
	vmw_generic_waiter_add(dev_priv, SVGA_IRQFLAG_ANY_FENCE,
	&dev_priv->fence_queue_waiters);
	}

	void vmw_seqno_waiter_remove(struct vmw_private *dev_priv)
	{
	vmw_generic_waiter_remove(dev_priv, SVGA_IRQFLAG_ANY_FENCE,
	&dev_priv->fence_queue_waiters);
	}

	void vmw_goal_waiter_add(struct vmw_private *dev_priv)
	{
	vmw_generic_waiter_add(dev_priv, SVGA_IRQFLAG_FENCE_GOAL,
	&dev_priv->goal_queue_waiters);
	}

	void vmw_goal_waiter_remove(struct vmw_private *dev_priv)
	{
	vmw_generic_waiter_remove(dev_priv, SVGA_IRQFLAG_FENCE_GOAL,
	&dev_priv->goal_queue_waiters);
	}

	int vmw_wait_seqno(struct vmw_private *dev_priv,
	bool lazy, uint32_t seqno,
	bool interruptible, unsigned long timeout)
	{
	long ret;
	struct vmw_fifo_state *fifo = &dev_priv->fifo;

	if (likely(dev_priv->last_read_seqno - seqno < VMW_FENCE_WRAP))
	return 0;

	if (likely(vmw_seqno_passed(dev_priv, seqno)))
	return 0;

	vmw_fifo_ping_host(dev_priv, SVGA_SYNC_GENERIC);

	if (!(fifo->capabilities & SVGA_FIFO_CAP_FENCE))
	return vmw_fallback_wait(dev_priv, lazy, true, seqno,
	interruptible, timeout);

	if (!(dev_priv->capabilities & SVGA_CAP_IRQMASK))
	return vmw_fallback_wait(dev_priv, lazy, false, seqno,
	interruptible, timeout);

	vmw_seqno_waiter_add(dev_priv);

	if (interruptible)
	ret = wait_event_interruptible_timeout
	(dev_priv->fence_queue,
	vmw_seqno_passed(dev_priv, seqno),
	timeout);
	else
	ret = wait_event_timeout
	(dev_priv->fence_queue,
	vmw_seqno_passed(dev_priv, seqno),
	timeout);

	vmw_seqno_waiter_remove(dev_priv);

	if (unlikely(ret == 0))
	ret = -EBUSY;
	else if (likely(ret > 0))
	ret = 0;

	return ret;
	}

	static void vmw_irq_preinstall(struct drm_device *dev)
	{
	struct vmw_private *dev_priv = vmw_priv(dev);
	uint32_t status;

	status = inl(dev_priv->io_start + VMWGFX_IRQSTATUS_PORT);
	outl(status, dev_priv->io_start + VMWGFX_IRQSTATUS_PORT);
	}

	void vmw_irq_uninstall(struct drm_device *dev)
	{
	struct vmw_private *dev_priv = vmw_priv(dev);
	uint32_t status;

	if (!(dev_priv->capabilities & SVGA_CAP_IRQMASK))
	return;

	if (!dev->irq_enabled)
	return;

	vmw_write(dev_priv, SVGA_REG_IRQMASK, 0);

	status = inl(dev_priv->io_start + VMWGFX_IRQSTATUS_PORT);
	outl(status, dev_priv->io_start + VMWGFX_IRQSTATUS_PORT);

	dev->irq_enabled = false;
	free_irq(dev->irq, dev);
	}

	/**
	* vmw_irq_install - Install the irq handlers
	*
	* @dev: Pointer to the drm device.
	* @irq: The irq number.
	* Return: Zero if successful. Negative number otherwise.
	*/
	int vmw_irq_install(struct drm_device *dev, int irq)
	{
	int ret;

	if (dev->irq_enabled)
	return -EBUSY;

	vmw_irq_preinstall(dev);

	ret = request_threaded_irq(irq, vmw_irq_handler, vmw_thread_fn,
	IRQF_SHARED, VMWGFX_DRIVER_NAME, dev);
	if (ret < 0)
	return ret;

	dev->irq_enabled = true;
	dev->irq = irq;

	return ret;
	}