drm/vmwgfx: Relax irq locking somewhat

[linux-2.6-block.git] / drivers / gpu / drm / vmwgfx / vmwgfx_irq.c

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 * Copyright © 2009-2015 VMware, Inc., Palo Alto, CA., USA
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#include <drm/drmP.h>
#include "vmwgfx_drv.h"

#define VMW_FENCE_WRAP (1 << 24)

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;

	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_ANY_FENCE |
			     SVGA_IRQFLAG_FENCE_GOAL)) {
		vmw_fences_update(dev_priv->fman);
		wake_up_all(&dev_priv->fence_queue);
	}

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

	if (masked_status & (SVGA_IRQFLAG_COMMAND_BUFFER |
			     SVGA_IRQFLAG_ERROR))
		vmw_cmdbuf_tasklet_schedule(dev_priv->cman);

	return IRQ_HANDLED;
}

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;
}

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

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

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

int vmw_irq_postinstall(struct drm_device *dev)
{
	return 0;
}

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;

	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);
}