[PATCH v3 5/5] drm/i915: Enable HPD interrupts with master ctl interrupt

[Animesh Manna]

While suspending the device hpd related interrupts are enabled
to get the interrupt when device is in suspend state.

Though display is in DC9 but system can be in S0 or S0i3 state.
Hot plug during S0 state will generate de_port_interrupt but if
system is in S0i3 state then display driver will get hotplug
interrupt as pcu_hpd_interrupt which will come via pmc. So
added the interrupt handling for pcu hpd interrupt.

v1: Initial version as RFC.

v2: Based on review comments from Imre, Ville,
    - separate hpd_bxt_pcu structure added.
    - pcu_irq_ack/pcu_irq_handler pair added to handle pcu interrupt.
    - sequence for enabling pcu interrupt is modified.
    - Removed the definition of pcu interrupt mask bit as it is matching
    with enable bit.

Cc: Imre Deak <imre.deak at intel.com>
Cc: Ville Syrjälä <ville.syrjala at linux.intel.com>
Signed-off-by: Animesh Manna <animesh.manna at intel.com>
Signed-off-by: A.Sunil Kamath <sunil.kamath at intel.com>
---
 drivers/gpu/drm/i915/i915_irq.c | 73 +++++++++++++++++++++++++++++++++++++++++
 drivers/gpu/drm/i915/i915_reg.h |  8 +++++
 2 files changed, 81 insertions(+)

diff --git a/drivers/gpu/drm/i915/i915_irq.c b/drivers/gpu/drm/i915/i915_irq.c
index a0e70f5..2028140 100644
--- a/drivers/gpu/drm/i915/i915_irq.c
+++ b/drivers/gpu/drm/i915/i915_irq.c
@@ -115,6 +115,12 @@ static const u32 hpd_bxt[HPD_NUM_PINS] = {
 	[HPD_PORT_C] = BXT_DE_PORT_HP_DDIC
 };
 
+static const u32 hpd_bxt_pcu[HPD_NUM_PINS] = {
+	[HPD_PORT_A] = BXT_PCU_DC9_HP_DDIA,
+	[HPD_PORT_B] = BXT_PCU_DC9_HP_DDIB,
+	[HPD_PORT_C] = BXT_PCU_DC9_HP_DDIC
+};
+
 /* IIR can theoretically queue up two events. Be paranoid. */
 #define GEN8_IRQ_RESET_NDX(type, which) do { \
 	I915_WRITE(GEN8_##type##_IMR(which), 0xffffffff); \
@@ -2537,12 +2543,49 @@ gen8_de_irq_handler(struct drm_i915_private *dev_priv, u32 master_ctl)
 	return ret;
 }
 
+static irqreturn_t
+gen8_pcu_irq_ack(struct drm_i915_private *dev_priv,
+		 u32 master_ctl, u32 *pcu_iir)
+{
+	irqreturn_t ret = IRQ_NONE;
+
+	if (master_ctl & GEN8_PCU_IRQ) {
+		*pcu_iir = I915_READ(GEN8_PCU_IIR);
+
+		if (*pcu_iir) {
+			I915_WRITE(GEN8_PCU_IIR, *pcu_iir);
+			ret = IRQ_HANDLED;
+		} else {
+			DRM_ERROR("The master control interrupt lied (PCU)!\n");
+		}
+	}
+
+	return ret;
+}
+
+static void
+gen8_pcu_irq_handler(struct drm_i915_private *dev_priv, u32 pcu_iir)
+{
+	bool found = false;
+
+	if (IS_BROXTON(dev_priv) && (pcu_iir & BXT_PCU_DC9_HOTPLUG_MASK)) {
+		u32 tmp_mask = pcu_iir & BXT_PCU_DC9_HOTPLUG_MASK;
+
+		bxt_hpd_irq_handler(dev_priv, tmp_mask,	hpd_bxt_pcu);
+		found = true;
+	}
+
+	if (!found)
+		DRM_ERROR("Unexpected PCU interrupt 0x%x\n", pcu_iir);
+}
+
 static irqreturn_t gen8_irq_handler(int irq, void *arg)
 {
 	struct drm_device *dev = arg;
 	struct drm_i915_private *dev_priv = to_i915(dev);
 	u32 master_ctl;
 	u32 gt_iir[4] = {};
+	u32 pcu_iir = 0;
 	irqreturn_t ret;
 
 	if (!intel_irqs_enabled(dev_priv))
@@ -2560,7 +2603,9 @@ static irqreturn_t gen8_irq_handler(int irq, void *arg)
 
 	/* Find, clear, then process each source of interrupt */
 	ret = gen8_gt_irq_ack(dev_priv, master_ctl, gt_iir);
+	ret |= gen8_pcu_irq_ack(dev_priv, master_ctl, &pcu_iir);
 	gen8_gt_irq_handler(dev_priv, gt_iir);
+	gen8_pcu_irq_handler(dev_priv, pcu_iir);
 	ret |= gen8_de_irq_handler(dev_priv, master_ctl);
 
 	I915_WRITE_FW(GEN8_MASTER_IRQ, GEN8_MASTER_IRQ_CONTROL);
@@ -4290,6 +4335,17 @@ void intel_irq_uninstall(struct drm_i915_private *dev_priv)
 	dev_priv->pm.irqs_enabled = false;
 }
 
+static void bxt_enable_pcu_interrupt(struct drm_i915_private *dev_priv)
+{
+	u32 de_pcu_hpd_enable_mask, de_pcu_imr, de_pcu_ier;
+
+	de_pcu_hpd_enable_mask = BXT_PCU_DC9_HOTPLUG_MASK;
+
+	de_pcu_imr = (I915_READ(GEN8_PCU_IMR) & ~de_pcu_hpd_enable_mask);
+	de_pcu_ier = (I915_READ(GEN8_PCU_IER) | de_pcu_hpd_enable_mask);
+	GEN5_IRQ_INIT(GEN8_PCU_, de_pcu_imr, de_pcu_ier);
+}
+
 /**
  * intel_runtime_pm_disable_interrupts - runtime interrupt disabling
  * @dev_priv: i915 device instance
@@ -4302,6 +4358,23 @@ void intel_runtime_pm_disable_interrupts(struct drm_i915_private *dev_priv)
 	dev_priv->drm.driver->irq_uninstall(&dev_priv->drm);
 	dev_priv->pm.irqs_enabled = false;
 	synchronize_irq(dev_priv->drm.irq);
+
+	if (IS_BROXTON(dev_priv) && dev_priv->vbt.hpd_wakeup_enabled) {
+		unsigned long flags = 0;
+
+		/* Enable HPD related interrupts during DC9 for HPD wakeup */
+		spin_lock_irqsave(&dev_priv->irq_lock, flags);
+		if (dev_priv->display.hpd_irq_setup)
+			dev_priv->display.hpd_irq_setup(dev_priv);
+		spin_unlock_irqrestore(&dev_priv->irq_lock, flags);
+
+		bxt_enable_pcu_interrupt(dev_priv);
+
+		dev_priv->pm.irqs_enabled = true;
+		I915_WRITE(GEN8_MASTER_IRQ, GEN8_MASTER_IRQ_CONTROL);
+		POSTING_READ(GEN8_MASTER_IRQ);
+
+	}
 }
 
 /**
diff --git a/drivers/gpu/drm/i915/i915_reg.h b/drivers/gpu/drm/i915/i915_reg.h
index 8e47b59..19717c0 100644
--- a/drivers/gpu/drm/i915/i915_reg.h
+++ b/drivers/gpu/drm/i915/i915_reg.h
@@ -6402,6 +6402,14 @@ enum {
 #define GEN8_PCU_IIR _MMIO(0x444e8)
 #define GEN8_PCU_IER _MMIO(0x444ec)
 
+/* BXT PCU DC9 hotplug control */
+#define BXT_PCU_DC9_HP_DDIA		(1<<31)
+#define BXT_PCU_DC9_HP_DDIB		(1<<30)
+#define BXT_PCU_DC9_HP_DDIC		(1<<29)
+#define BXT_PCU_DC9_HOTPLUG_MASK	(BXT_PCU_DC9_HP_DDIA | \
+					 BXT_PCU_DC9_HP_DDIB | \
+					 BXT_PCU_DC9_HP_DDIC)
+
 #define ILK_DISPLAY_CHICKEN2	_MMIO(0x42004)
 /* Required on all Ironlake and Sandybridge according to the B-Spec. */
 #define  ILK_ELPIN_409_SELECT	(1 << 25)
-- 
2.7.4