drm/i915/dg1: add support for the master unit interrupt

DG1 has master unit interrupt register which is used to indicate the
correct source of interrupt.

v2: fix coding style on register definition

Cc: Radhakrishna Sripada <radhakrishna.sripada@intel.com>
Cc: Daniele Spurio Ceraolo <daniele.ceraolospurio@intel.com>
Cc: Matt Roper <matthew.d.roper@intel.com>
Signed-off-by: Lucas De Marchi <lucas.demarchi@intel.com>
Reviewed-by: José Roberto de Souza <jose.souza@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20200713182321.12390-4-lucas.demarchi@intel.com

drivers/gpu/drm/i915/i915_debugfs.c

@@ -495,6 +495,10 @@ static int i915_interrupt_info(struct seq_file *m, void *data)
 		seq_printf(m, "PCU interrupt enable:\t%08x\n",
 			   I915_READ(GEN8_PCU_IER));
 	} else if (INTEL_GEN(dev_priv) >= 11) {
+		if (HAS_MASTER_UNIT_IRQ(dev_priv))
+			seq_printf(m, "Master Unit Interrupt Control:  %08x\n",
+				   I915_READ(DG1_MSTR_UNIT_INTR));
+
 		seq_printf(m, "Master Interrupt Control:  %08x\n",
 			   I915_READ(GEN11_GFX_MSTR_IRQ));
 

drivers/gpu/drm/i915/i915_irq.c

@@ -2584,6 +2584,46 @@ static irqreturn_t gen11_irq_handler(int irq, void *arg)
 				   gen11_master_intr_enable);
 }
 
+static u32 dg1_master_intr_disable_and_ack(void __iomem * const regs)
+{
+	u32 val;
+
+	/* First disable interrupts */
+	raw_reg_write(regs, DG1_MSTR_UNIT_INTR, 0);
+
+	/* Get the indication levels and ack the master unit */
+	val = raw_reg_read(regs, DG1_MSTR_UNIT_INTR);
+	if (unlikely(!val))
+		return 0;
+
+	raw_reg_write(regs, DG1_MSTR_UNIT_INTR, val);
+
+	/*
+	 * Now with master disabled, get a sample of level indications
+	 * for this interrupt and ack them right away - we keep GEN11_MASTER_IRQ
+	 * out as this bit doesn't exist anymore for DG1
+	 */
+	val = raw_reg_read(regs, GEN11_GFX_MSTR_IRQ) & ~GEN11_MASTER_IRQ;
+	if (unlikely(!val))
+		return 0;
+
+	raw_reg_write(regs, GEN11_GFX_MSTR_IRQ, val);
+
+	return val;
+}
+
+static inline void dg1_master_intr_enable(void __iomem * const regs)
+{
+	raw_reg_write(regs, DG1_MSTR_UNIT_INTR, DG1_MSTR_IRQ);
+}
+
+static irqreturn_t dg1_irq_handler(int irq, void *arg)
+{
+	return __gen11_irq_handler(arg,
+				   dg1_master_intr_disable_and_ack,
+				   dg1_master_intr_enable);
+}
+
 /* Called from drm generic code, passed 'crtc' which
  * we use as a pipe index
  */
@@ -2920,6 +2960,9 @@ static void gen11_irq_reset(struct drm_i915_private *dev_priv)
 {
 	struct intel_uncore *uncore = &dev_priv->uncore;
 
+	if (HAS_MASTER_UNIT_IRQ(dev_priv))
+		dg1_master_intr_disable_and_ack(dev_priv->uncore.regs);
+	else
 		gen11_master_intr_disable(dev_priv->uncore.regs);
 
 	gen11_gt_irq_reset(&dev_priv->gt);
@@ -3517,8 +3560,13 @@ static void gen11_irq_postinstall(struct drm_i915_private *dev_priv)
 
 	I915_WRITE(GEN11_DISPLAY_INT_CTL, GEN11_DISPLAY_IRQ_ENABLE);
 
+	if (HAS_MASTER_UNIT_IRQ(dev_priv)) {
+		dg1_master_intr_enable(uncore->regs);
+		POSTING_READ(DG1_MSTR_UNIT_INTR);
+	} else {
 		gen11_master_intr_enable(uncore->regs);
 		POSTING_READ(GEN11_GFX_MSTR_IRQ);
+	}
 }
 
 static void cherryview_irq_postinstall(struct drm_i915_private *dev_priv)
@@ -4043,6 +4091,8 @@ static irq_handler_t intel_irq_handler(struct drm_i915_private *dev_priv)
 		else
 			return i8xx_irq_handler;
 	} else {
+		if (HAS_MASTER_UNIT_IRQ(dev_priv))
+			return dg1_irq_handler;
 		if (INTEL_GEN(dev_priv) >= 11)
 			return gen11_irq_handler;
 		else if (INTEL_GEN(dev_priv) >= 8)

drivers/gpu/drm/i915/i915_reg.h

@@ -7733,6 +7733,10 @@ enum {
 #define  GEN11_GT_DW1_IRQ		(1 << 1)
 #define  GEN11_GT_DW0_IRQ		(1 << 0)
 
+#define DG1_MSTR_UNIT_INTR		_MMIO(0x190008)
+#define   DG1_MSTR_IRQ			REG_BIT(31)
+#define   DG1_MSTR_UNIT(u)		REG_BIT(u)
+
 #define GEN11_DISPLAY_INT_CTL		_MMIO(0x44200)
 #define  GEN11_DISPLAY_IRQ_ENABLE	(1 << 31)
 #define  GEN11_AUDIO_CODEC_IRQ		(1 << 24)