drm/i915/vgpu: Neuter forcewakes for VGPU more thoroughly

If we avoid initializing forcewake domains when running as
a guest, and also use gen2 mmio accessors in that case, we
can avoid the timer traffic and any looping through the
forcewake code which is currently just so it can end up in
the no-op forcewake implementation.

Signed-off-by: Tvrtko Ursulin <tvrtko.ursulin@intel.com>
Cc: Weinan Li <weinan.z.li@intel.com>
Cc: Chris Wilson <chris@chris-wilson.co.uk>
Reviewed-by: Chris Wilson <chris@chris-wilson.co.uk>
Tested-by: Terrence Xu <terrence.xu@intel.com>
Link: http://patchwork.freedesktop.org/patch/msgid/20170310095747.12258-1-tvrtko.ursulin@linux.intel.com
[tursulin: commit spelling fix]

drivers/gpu/drm/i915/intel_uncore.c

@@ -137,13 +137,6 @@ fw_domains_put(struct drm_i915_private *dev_priv, enum forcewake_domains fw_doma
 	dev_priv->uncore.fw_domains_active &= ~fw_domains;
 }
 
-static void
-vgpu_fw_domains_nop(struct drm_i915_private *dev_priv,
-		    enum forcewake_domains fw_domains)
-{
-	/* Guest driver doesn't need to takes care forcewake. */
-}
-
 static void
 fw_domains_posting_read(struct drm_i915_private *dev_priv)
 {
@@ -1187,7 +1180,7 @@ static void fw_domain_init(struct drm_i915_private *dev_priv,
 
 static void intel_uncore_fw_domains_init(struct drm_i915_private *dev_priv)
 {
-	if (INTEL_INFO(dev_priv)->gen <= 5)
+	if (INTEL_GEN(dev_priv) <= 5 || intel_vgpu_active(dev_priv))
 		return;
 
 	if (IS_GEN9(dev_priv)) {
@@ -1273,11 +1266,6 @@ static void intel_uncore_fw_domains_init(struct drm_i915_private *dev_priv)
 			       FORCEWAKE, FORCEWAKE_ACK);
 	}
 
-	if (intel_vgpu_active(dev_priv)) {
-		dev_priv->uncore.funcs.force_wake_get = vgpu_fw_domains_nop;
-		dev_priv->uncore.funcs.force_wake_put = vgpu_fw_domains_nop;
-	}
-
 	/* All future platforms are expected to require complex power gating */
 	WARN_ON(dev_priv->uncore.fw_domains == 0);
 }
@@ -1327,22 +1315,22 @@ void intel_uncore_init(struct drm_i915_private *dev_priv)
 	dev_priv->uncore.pmic_bus_access_nb.notifier_call =
 		i915_pmic_bus_access_notifier;
 
-	switch (INTEL_INFO(dev_priv)->gen) {
-	default:
-	case 9:
-		ASSIGN_FW_DOMAINS_TABLE(__gen9_fw_ranges);
-		ASSIGN_WRITE_MMIO_VFUNCS(fwtable);
-		ASSIGN_READ_MMIO_VFUNCS(fwtable);
-		if (HAS_DECOUPLED_MMIO(dev_priv)) {
-			dev_priv->uncore.funcs.mmio_readl =
-						gen9_decoupled_read32;
-			dev_priv->uncore.funcs.mmio_readq =
-						gen9_decoupled_read64;
-			dev_priv->uncore.funcs.mmio_writel =
-						gen9_decoupled_write32;
+	if (IS_GEN(dev_priv, 2, 4) || intel_vgpu_active(dev_priv)) {
+		ASSIGN_WRITE_MMIO_VFUNCS(gen2);
+		ASSIGN_READ_MMIO_VFUNCS(gen2);
+	} else if (IS_GEN5(dev_priv)) {
+		ASSIGN_WRITE_MMIO_VFUNCS(gen5);
+		ASSIGN_READ_MMIO_VFUNCS(gen5);
+	} else if (IS_GEN(dev_priv, 6, 7)) {
+		ASSIGN_WRITE_MMIO_VFUNCS(gen6);
+
+		if (IS_VALLEYVIEW(dev_priv)) {
+			ASSIGN_FW_DOMAINS_TABLE(__vlv_fw_ranges);
+			ASSIGN_READ_MMIO_VFUNCS(fwtable);
+		} else {
+			ASSIGN_READ_MMIO_VFUNCS(gen6);
 		}
-		break;
-	case 8:
+	} else if (IS_GEN8(dev_priv)) {
 		if (IS_CHERRYVIEW(dev_priv)) {
 			ASSIGN_FW_DOMAINS_TABLE(__chv_fw_ranges);
 			ASSIGN_WRITE_MMIO_VFUNCS(fwtable);
@@ -1352,28 +1340,18 @@ void intel_uncore_init(struct drm_i915_private *dev_priv)
 			ASSIGN_WRITE_MMIO_VFUNCS(gen8);
 			ASSIGN_READ_MMIO_VFUNCS(gen6);
 		}
-		break;
-	case 7:
-	case 6:
-		ASSIGN_WRITE_MMIO_VFUNCS(gen6);
-
-		if (IS_VALLEYVIEW(dev_priv)) {
-			ASSIGN_FW_DOMAINS_TABLE(__vlv_fw_ranges);
-			ASSIGN_READ_MMIO_VFUNCS(fwtable);
-		} else {
-			ASSIGN_READ_MMIO_VFUNCS(gen6);
+	} else {
+		ASSIGN_FW_DOMAINS_TABLE(__gen9_fw_ranges);
+		ASSIGN_WRITE_MMIO_VFUNCS(fwtable);
+		ASSIGN_READ_MMIO_VFUNCS(fwtable);
+		if (HAS_DECOUPLED_MMIO(dev_priv)) {
+			dev_priv->uncore.funcs.mmio_readl =
+						gen9_decoupled_read32;
+			dev_priv->uncore.funcs.mmio_readq =
+						gen9_decoupled_read64;
+			dev_priv->uncore.funcs.mmio_writel =
+						gen9_decoupled_write32;
 		}
-		break;
-	case 5:
-		ASSIGN_WRITE_MMIO_VFUNCS(gen5);
-		ASSIGN_READ_MMIO_VFUNCS(gen5);
-		break;
-	case 4:
-	case 3:
-	case 2:
-		ASSIGN_WRITE_MMIO_VFUNCS(gen2);
-		ASSIGN_READ_MMIO_VFUNCS(gen2);
-		break;
 	}
 
 	iosf_mbi_register_pmic_bus_access_notifier(