[PATCH 25/49] drm/i915/bxt: Add DDI hpd handler

Imre Deak
2015-03-17T09:40:41Z

From: Shashank Sharma <shashank.sharma@intel.com>

This patch adds a hot plug interrupt handler function for BXT.
What this function typically does is:
1. Check if hot plug is enabled from hot plug control register.
2. Call hpd_irq_handler with appropriate trigger to detect a
plug storm and schedule a bottom half.
3. Clear sticky status bits in hot plug control register..

Reviewed-by: Satheeshakrishna M <satheeshakrishna.m@intel.com>
Signed-off-by: Damien Lespiau <damien.lespiau@intel.com>
Signed-off-by: Shashank Sharma <shashank.sharma@intel.com>
---
drivers/gpu/drm/i915/i915_irq.c | 45 +++++++++++++++++++++++++++++++++++++++--
1 file changed, 43 insertions(+), 2 deletions(-)

diff --git a/drivers/gpu/drm/i915/i915_irq.c b/drivers/gpu/drm/i915/i915_irq.c
index a51c00e..4a2f85b 100644
--- a/drivers/gpu/drm/i915/i915_irq.c
+++ b/drivers/gpu/drm/i915/i915_irq.c
@@ -2227,6 +2227,38 @@ static irqreturn_t ironlake_irq_handler(int irq, void *arg)
return ret;
}

+static void bxt_hpd_handler(struct drm_device *dev, uint32_t iir_status)
+{
+ struct drm_i915_private *dev_priv = dev->dev_private;
+ uint32_t hp_control;
+ uint32_t hp_trigger;
+
+ /* Get the status */
+ hp_trigger = iir_status & BXT_DE_PORT_HOTPLUG_MASK;
+ hp_control = I915_READ(BXT_HOTPLUG_CTL);
+
+ /* Hotplug not enabled ? */
+ if (unlikely(!(hp_control & BXT_HOTPLUG_CTL_MASK))) {
+ DRM_ERROR("Interrupt when HPD disabled\n");
+ return;
+ }
+
+ DRM_DEBUG_DRIVER("hotplug event received, stat 0x%08x\n",
+ hp_control & BXT_HOTPLUG_CTL_MASK);
+
+ /* Check for HPD storm and schedule bottom half */
+ intel_hpd_irq_handler(dev, hp_trigger, hp_control, hpd_bxt);
+
+ /*
+ * Todo: Save the hot plug status for bottom half before
+ * clearing the sticky status bits, else the status will be
+ * lost.
+ */
+
+ /* Clear sticky bits in hpd status */
+ I915_WRITE(BXT_HOTPLUG_CTL, hp_control);
+}
+
static irqreturn_t gen8_irq_handler(int irq, void *arg)
{
struct drm_device *dev = arg;
@@ -2236,6 +2268,7 @@ static irqreturn_t gen8_irq_handler(int irq, void *arg)
uint32_t tmp = 0;
enum pipe pipe;
u32 aux_mask = GEN8_AUX_CHANNEL_A;
+ bool found = false;

if (!intel_irqs_enabled(dev_priv))
return IRQ_NONE;
@@ -2276,9 +2309,17 @@ static irqreturn_t gen8_irq_handler(int irq, void *arg)
I915_WRITE(GEN8_DE_PORT_IIR, tmp);
ret = IRQ_HANDLED;

- if (tmp & aux_mask)
+ if (tmp & aux_mask) {
dp_aux_irq_handler(dev);
- else
+ found = true;
+ }
+
+ if (tmp & BXT_DE_PORT_HOTPLUG_MASK) {
+ bxt_hpd_handler(dev, tmp);
+ found = true;
+ }
+
+ if (!found)
DRM_ERROR("Unexpected DE Port interrupt\n");
}
else
--
2.1.0