drm/i915/icl: Use hw engine class, instance to find irq handler

Interrupt identity register we already read from hardware
contains engine class and instance fields. Leverage
these fields to find correct engine to handle the interrupt.

v3: rebase on top of rps intr
    use correct class / instance limits (Michel)
v4: split engine/other handling
v5: empty iir is not err (Daniele, Michel)

Suggested-by: Daniele Ceraolo Spurio <daniele.ceraolospurio@intel.com>
Cc: Daniele Ceraolo Spurio <daniele.ceraolospurio@intel.com>
Cc: Chris Wilson <chris@chris-wilson.co.uk>
Cc: Tvrtko Ursulin <tvrtko.ursulin@intel.com>
Cc: Michel Thierry <michel.thierry@intel.com>
Signed-off-by: Mika Kuoppala <mika.kuoppala@linux.intel.com>
Reviewed-by: Daniele Ceraolo Spurio <daniele.ceraolospurio@intel.com>
Reviewed-by: Michel Thierry <michel.thierry@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20180406093145.14389-1-mika.kuoppala@linux.intel.com

drivers/gpu/drm/i915/i915_irq.c

@@ -2732,47 +2732,9 @@ static void __fini_wedge(struct wedge_me *w)
 	     (W)->i915;							\
 	     __fini_wedge((W)))
 
-static void
-gen11_gt_engine_irq_handler(struct drm_i915_private * const i915,
-			    const unsigned int bank,
-			    const unsigned int engine_n,
-			    const u16 iir)
-{
-	struct intel_engine_cs ** const engine = i915->engine;
-
-	switch (bank) {
-	case 0:
-		switch (engine_n) {
-
-		case GEN11_RCS0:
-			return gen8_cs_irq_handler(engine[RCS], iir);
-
-		case GEN11_BCS:
-			return gen8_cs_irq_handler(engine[BCS], iir);
-		}
-	case 1:
-		switch (engine_n) {
-
-		case GEN11_VCS(0):
-			return gen8_cs_irq_handler(engine[_VCS(0)], iir);
-		case GEN11_VCS(1):
-			return gen8_cs_irq_handler(engine[_VCS(1)], iir);
-		case GEN11_VCS(2):
-			return gen8_cs_irq_handler(engine[_VCS(2)], iir);
-		case GEN11_VCS(3):
-			return gen8_cs_irq_handler(engine[_VCS(3)], iir);
-
-		case GEN11_VECS(0):
-			return gen8_cs_irq_handler(engine[_VECS(0)], iir);
-		case GEN11_VECS(1):
-			return gen8_cs_irq_handler(engine[_VECS(1)], iir);
-		}
-	}
-}
-
 static u32
-gen11_gt_engine_intr(struct drm_i915_private * const i915,
-		     const unsigned int bank, const unsigned int bit)
+gen11_gt_engine_identity(struct drm_i915_private * const i915,
+			 const unsigned int bank, const unsigned int bit)
 {
 	void __iomem * const regs = i915->regs;
 	u32 timeout_ts;
@@ -2799,7 +2761,54 @@ gen11_gt_engine_intr(struct drm_i915_private * const i915,
 	raw_reg_write(regs, GEN11_INTR_IDENTITY_REG(bank),
 		      GEN11_INTR_DATA_VALID);
 
-	return ident & GEN11_INTR_ENGINE_MASK;
+	return ident;
+}
+
+static void
+gen11_other_irq_handler(struct drm_i915_private * const i915,
+			const u8 instance, const u16 iir)
+{
+	WARN_ONCE(1, "unhandled other interrupt instance=0x%x, iir=0x%x\n",
+		  instance, iir);
+}
+
+static void
+gen11_engine_irq_handler(struct drm_i915_private * const i915,
+			 const u8 class, const u8 instance, const u16 iir)
+{
+	struct intel_engine_cs *engine;
+
+	if (instance <= MAX_ENGINE_INSTANCE)
+		engine = i915->engine_class[class][instance];
+	else
+		engine = NULL;
+
+	if (likely(engine))
+		return gen8_cs_irq_handler(engine, iir);
+
+	WARN_ONCE(1, "unhandled engine interrupt class=0x%x, instance=0x%x\n",
+		  class, instance);
+}
+
+static void
+gen11_gt_identity_handler(struct drm_i915_private * const i915,
+			  const u32 identity)
+{
+	const u8 class = GEN11_INTR_ENGINE_CLASS(identity);
+	const u8 instance = GEN11_INTR_ENGINE_INSTANCE(identity);
+	const u16 intr = GEN11_INTR_ENGINE_INTR(identity);
+
+	if (unlikely(!intr))
+		return;
+
+	if (class <= COPY_ENGINE_CLASS)
+		return gen11_engine_irq_handler(i915, class, instance, intr);
+
+	if (class == OTHER_CLASS)
+		return gen11_other_irq_handler(i915, instance, intr);
+
+	WARN_ONCE(1, "unknown interrupt class=0x%x, instance=0x%x, intr=0x%x\n",
+		  class, instance, intr);
 }
 
 static void
@@ -2824,12 +2833,10 @@ gen11_gt_irq_handler(struct drm_i915_private * const i915,
 		}
 
 		for_each_set_bit(bit, &intr_dw, 32) {
-			const u16 iir = gen11_gt_engine_intr(i915, bank, bit);
+			const u32 ident = gen11_gt_engine_identity(i915,
+								   bank, bit);
 
-			if (unlikely(!iir))
-				continue;
-
-			gen11_gt_engine_irq_handler(i915, bank, bit, iir);
+			gen11_gt_identity_handler(i915, ident);
 		}
 
 		/* Clear must be after shared has been served for engine */