[PATCH 08/18] drm/i915: Create a more generic pm handler for hsw+

Ben Widawsky
2012-11-06T16:26:17Z

HSW has some special requirements for the VEBOX. Splitting out the
interrupt handler will make the code a bit nicer and less error prone
when we begin to handle those.

The slight functional change in this patch (queueing work while holding
the spinlock) is intentional as it makes a subsequent patch a bit nicer.
The change should also only effect HSW platforms.

Based on patches from:
CC: Haihao Xiang <haihao.xiang@intel.com>
Signed-off-by: Ben Widawsky <ben@bwidawsk.net>
---
drivers/gpu/drm/i915/i915_irq.c | 30 +++++++++++++++++++++++++++++-
1 file changed, 29 insertions(+), 1 deletion(-)

diff --git a/drivers/gpu/drm/i915/i915_irq.c b/drivers/gpu/drm/i915/i915_irq.c
index 2604867..d5aef6c 100644
--- a/drivers/gpu/drm/i915/i915_irq.c
+++ b/drivers/gpu/drm/i915/i915_irq.c
@@ -500,6 +500,7 @@ static void snb_gt_irq_handler(struct drm_device *dev,
ivybridge_handle_parity_error(dev);
}

+/* Legacy way of handling PM interrupts */
static void gen6_queue_rps_work(struct drm_i915_private *dev_priv,
u32 pm_iir)
{
@@ -524,6 +525,31 @@ static void gen6_queue_rps_work(struct drm_i915_private *dev_priv,
queue_work(dev_priv->wq, &dev_priv->rps.work);
}

+/* Unlike gen6_queue_rps_work() from which this function is originally derived,
+ * we must be able to deal with other PM interrupts. This is complicated because
+ * of the way in which we use the masks to defer the RPS work (which for
+ * posterity is necessary because of forcewake).
+ */
+static void hsw_pm_irq_handler(struct drm_i915_private *dev_priv,
+ u32 pm_iir)
+{
+ unsigned long flags;
+
+ spin_lock_irqsave(&dev_priv->rps.lock, flags);
+ dev_priv->rps.pm_iir |= pm_iir & GEN6_PM_DEFERRED_EVENTS;
+ if (dev_priv->rps.pm_iir) {
+ I915_WRITE(GEN6_PMIMR, dev_priv->rps.pm_iir);
+ /* We never want to mask useful interrupts. (also posting read) */
+ WARN_ON(I915_READ_NOTRACE(GEN6_PMIMR) & ~GEN6_PM_DEFERRED_EVENTS);
+ /* TODO: if queue_work is slow, move it out of the spinlock */
+ queue_work(dev_priv->wq, &dev_priv->rps.work);
+ }
+ spin_unlock_irqrestore(&dev_priv->rps.lock, flags);
+
+ if (pm_iir & ~GEN6_PM_DEFERRED_EVENTS)
+ DRM_ERROR("Unexpected PM interrupted\n");
+}
+
static irqreturn_t valleyview_irq_handler(int irq, void *arg)
{
struct drm_device *dev = (struct drm_device *) arg;
@@ -731,7 +757,9 @@ static irqreturn_t ivybridge_irq_handler(int irq, void *arg)

pm_iir = I915_READ(GEN6_PMIIR);
if (pm_iir) {
- if (pm_iir & GEN6_PM_DEFERRED_EVENTS)
+ if (IS_HASWELL(dev))
+ hsw_pm_irq_handler(dev_priv, pm_iir);
+ else if (pm_iir & GEN6_PM_DEFERRED_EVENTS)
gen6_queue_rps_work(dev_priv, pm_iir);
I915_WRITE(GEN6_PMIIR, pm_iir);
ret = IRQ_HANDLED;
--
1.8.0