drm/i915/bxt: Add DDI hpd handler

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..

v2: (jani)
- drop redundant unlikely()
- s/Todo/FIXME:/ in code comment
- declare 'found' var in the scope where it's used
- check for IS_BROXTON before handling BXT_DE_PORT_HOTPLUG_MASK

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> (v1)
Signed-off-by: Imre Deak <imre.deak@intel.com>
Reviewed-by: Jani Nikula <jani.nikula@intel.com>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>

diff --git a/drivers/gpu/drm/i915/i915_irq.c b/drivers/gpu/drm/i915/i915_irq.c
index 7f73f71741ae12487959bfc5feedf6a96bdfff7f..ac68b5bd8f1503a1a90ce5dc319b181148f77740 100644 (file)
--- a/drivers/gpu/drm/i915/i915_irq.c
+++ b/drivers/gpu/drm/i915/i915_irq.c
@@ -2152,6 +2152,38 @@ 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 (!(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);
+
+       /*
+        * FIXME: 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;
@@ -2197,12 +2229,22 @@ static irqreturn_t gen8_irq_handler(int irq, void *arg)
        if (master_ctl & GEN8_DE_PORT_IRQ) {
                tmp = I915_READ(GEN8_DE_PORT_IIR);
                if (tmp) {
+                       bool found = false;
+
                        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 (IS_BROXTON(dev) && tmp & BXT_DE_PORT_HOTPLUG_MASK) {
+                               bxt_hpd_handler(dev, tmp);
+                               found = true;
+                       }
+
+                       if (!found)
                                DRM_ERROR("Unexpected DE Port interrupt\n");
                }
                else