[Intel-gfx] [PATCH] drm/i915/bxt: WA for swapped HPD pins in A stepping

[Sonika Jindal]

As per bspec, on BXT A0/A1, sw needs to activate DDIA HPD logic
and interrupts to check the external panel connection.
And remove the redundant comment.

v2: Remove redundant IS_BROXTON check, Add comment about port C not
connected, and rephrase the commit message to include only what we
are doing here (Imre)

Signed-off-by: Sonika Jindal <sonika.jindal at intel.com>
---
 drivers/gpu/drm/i915/i915_irq.c |   38 +++++++++++++++++++++++++++++---------
 1 file changed, 29 insertions(+), 9 deletions(-)

diff --git a/drivers/gpu/drm/i915/i915_irq.c b/drivers/gpu/drm/i915/i915_irq.c
index eb52a03..760539c 100644
--- a/drivers/gpu/drm/i915/i915_irq.c
+++ b/drivers/gpu/drm/i915/i915_irq.c
@@ -88,7 +88,11 @@ static const u32 hpd_status_i915[HPD_NUM_PINS] = {
 	[HPD_PORT_D] = PORTD_HOTPLUG_INT_STATUS
 };
 
-/* BXT hpd list */
+/* Port C is not connected on bxt A0/A1 */
+static const u32 hpd_bxt_a0[HPD_NUM_PINS] = {
+	[HPD_PORT_B] = BXT_DE_PORT_HP_DDIA
+};
+
 static const u32 hpd_bxt[HPD_NUM_PINS] = {
 	[HPD_PORT_B] = BXT_DE_PORT_HP_DDIB,
 	[HPD_PORT_C] = BXT_DE_PORT_HP_DDIC
@@ -2257,6 +2261,7 @@ static void bxt_hpd_handler(struct drm_device *dev, uint32_t iir_status)
 	struct drm_i915_private *dev_priv = dev->dev_private;
 	u32 hp_control, hp_trigger;
 	u32 pin_mask, long_mask;
+	const u32 *hpd;
 
 	/* Get the status */
 	hp_trigger = iir_status & BXT_DE_PORT_HOTPLUG_MASK;
@@ -2271,7 +2276,12 @@ static void bxt_hpd_handler(struct drm_device *dev, uint32_t iir_status)
 	/* Clear sticky bits in hpd status */
 	I915_WRITE(BXT_HOTPLUG_CTL, hp_control);
 
-	pch_get_hpd_pins(&pin_mask, &long_mask, hp_trigger, hp_control, hpd_bxt);
+	if (INTEL_REVID(dev) < BXT_REVID_B0)
+		hpd = hpd_bxt_a0;
+	else
+		hpd = hpd_bxt;
+
+	pch_get_hpd_pins(&pin_mask, &long_mask, hp_trigger, hp_control, hpd);
 	intel_hpd_irq_handler(dev, pin_mask, long_mask);
 }
 
@@ -3315,8 +3325,15 @@ static void bxt_hpd_irq_setup(struct drm_device *dev)
 	/* Now, enable HPD */
 	for_each_intel_encoder(dev, intel_encoder) {
 		if (dev_priv->hotplug.stats[intel_encoder->hpd_pin].state
-				== HPD_ENABLED)
-			hotplug_port |= hpd_bxt[intel_encoder->hpd_pin];
+				== HPD_ENABLED) {
+			const u32 *hpd;
+
+			if (INTEL_REVID(dev) < BXT_REVID_B0)
+				hpd = hpd_bxt_a0;
+			else
+				hpd = hpd_bxt;
+			hotplug_port |= hpd[intel_encoder->hpd_pin];
+		}
 	}
 
 	/* Mask all HPD control bits */
@@ -3324,11 +3341,14 @@ static void bxt_hpd_irq_setup(struct drm_device *dev)
 
 	/* Enable requested port in hotplug control */
 	/* TODO: implement (short) HPD support on port A */
-	WARN_ON_ONCE(hotplug_port & BXT_DE_PORT_HP_DDIA);
-	if (hotplug_port & BXT_DE_PORT_HP_DDIB)
-		hotplug_ctrl |= BXT_DDIB_HPD_ENABLE;
-	if (hotplug_port & BXT_DE_PORT_HP_DDIC)
-		hotplug_ctrl |= BXT_DDIC_HPD_ENABLE;
+	if (INTEL_REVID(dev) < BXT_REVID_B0 && (hotplug_port & BXT_DE_PORT_HP_DDIA))
+			hotplug_ctrl |= BXT_DDIA_HPD_ENABLE;
+	else {
+		if (hotplug_port & BXT_DE_PORT_HP_DDIB)
+			hotplug_ctrl |= BXT_DDIB_HPD_ENABLE;
+		if (hotplug_port & BXT_DE_PORT_HP_DDIC)
+			hotplug_ctrl |= BXT_DDIC_HPD_ENABLE;
+	}
 	I915_WRITE(BXT_HOTPLUG_CTL, hotplug_ctrl);
 
 	/* Unmask DDI hotplug in IMR */
-- 
1.7.10.4