drm/i915: abstract PCH type detection from PCH id

Make the logic in intel_detect_pch() easier to follow, and make the PCH
id to type mapping reusable. No functional changes.
Reviewed-by: Rodrigo Vivi <rodrigo.vivi@intel.com>
Signed-off-by: Jani Nikula <jani.nikula@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/3bd4ffcd284cdbd4e8dc77ab02d97ded422e0c21.1517851783.git.jani.nikula@intel.com

drivers/gpu/drm/i915/i915_drv.c

@@ -122,6 +122,75 @@ static bool i915_error_injected(struct drm_i915_private *dev_priv)
 		      i915_error_injected(dev_priv) ? KERN_DEBUG : KERN_ERR, \
 		      fmt, ##__VA_ARGS__)
 
+/* Map PCH device id to PCH type, or PCH_NONE if unknown. */
+static enum intel_pch
+intel_pch_type(const struct drm_i915_private *dev_priv, unsigned short id)
+{
+	switch (id) {
+	case INTEL_PCH_IBX_DEVICE_ID_TYPE:
+		DRM_DEBUG_KMS("Found Ibex Peak PCH\n");
+		WARN_ON(!IS_GEN5(dev_priv));
+		return PCH_IBX;
+	case INTEL_PCH_CPT_DEVICE_ID_TYPE:
+		DRM_DEBUG_KMS("Found CougarPoint PCH\n");
+		WARN_ON(!IS_GEN6(dev_priv) && !IS_IVYBRIDGE(dev_priv));
+		return PCH_CPT;
+	case INTEL_PCH_PPT_DEVICE_ID_TYPE:
+		DRM_DEBUG_KMS("Found PantherPoint PCH\n");
+		WARN_ON(!IS_GEN6(dev_priv) && !IS_IVYBRIDGE(dev_priv));
+		/* PantherPoint is CPT compatible */
+		return PCH_CPT;
+	case INTEL_PCH_LPT_DEVICE_ID_TYPE:
+		DRM_DEBUG_KMS("Found LynxPoint PCH\n");
+		WARN_ON(!IS_HASWELL(dev_priv) && !IS_BROADWELL(dev_priv));
+		WARN_ON(IS_HSW_ULT(dev_priv) || IS_BDW_ULT(dev_priv));
+		return PCH_LPT;
+	case INTEL_PCH_LPT_LP_DEVICE_ID_TYPE:
+		DRM_DEBUG_KMS("Found LynxPoint LP PCH\n");
+		WARN_ON(!IS_HASWELL(dev_priv) && !IS_BROADWELL(dev_priv));
+		WARN_ON(!IS_HSW_ULT(dev_priv) && !IS_BDW_ULT(dev_priv));
+		return PCH_LPT;
+	case INTEL_PCH_WPT_DEVICE_ID_TYPE:
+		DRM_DEBUG_KMS("Found WildcatPoint PCH\n");
+		WARN_ON(!IS_HASWELL(dev_priv) && !IS_BROADWELL(dev_priv));
+		WARN_ON(IS_HSW_ULT(dev_priv) || IS_BDW_ULT(dev_priv));
+		/* WildcatPoint is LPT compatible */
+		return PCH_LPT;
+	case INTEL_PCH_WPT_LP_DEVICE_ID_TYPE:
+		DRM_DEBUG_KMS("Found WildcatPoint LP PCH\n");
+		WARN_ON(!IS_HASWELL(dev_priv) && !IS_BROADWELL(dev_priv));
+		WARN_ON(!IS_HSW_ULT(dev_priv) && !IS_BDW_ULT(dev_priv));
+		/* WildcatPoint is LPT compatible */
+		return PCH_LPT;
+	case INTEL_PCH_SPT_DEVICE_ID_TYPE:
+		DRM_DEBUG_KMS("Found SunrisePoint PCH\n");
+		WARN_ON(!IS_SKYLAKE(dev_priv) && !IS_KABYLAKE(dev_priv));
+		return PCH_SPT;
+	case INTEL_PCH_SPT_LP_DEVICE_ID_TYPE:
+		DRM_DEBUG_KMS("Found SunrisePoint LP PCH\n");
+		WARN_ON(!IS_SKYLAKE(dev_priv) && !IS_KABYLAKE(dev_priv));
+		return PCH_SPT;
+	case INTEL_PCH_KBP_DEVICE_ID_TYPE:
+		DRM_DEBUG_KMS("Found Kaby Lake PCH (KBP)\n");
+		WARN_ON(!IS_SKYLAKE(dev_priv) && !IS_KABYLAKE(dev_priv) &&
+			!IS_COFFEELAKE(dev_priv));
+		return PCH_KBP;
+	case INTEL_PCH_CNP_DEVICE_ID_TYPE:
+		DRM_DEBUG_KMS("Found Cannon Lake PCH (CNP)\n");
+		WARN_ON(!IS_CANNONLAKE(dev_priv) && !IS_COFFEELAKE(dev_priv));
+		return PCH_CNP;
+	case INTEL_PCH_CNP_LP_DEVICE_ID_TYPE:
+		DRM_DEBUG_KMS("Found Cannon Lake LP PCH (CNP-LP)\n");
+		WARN_ON(!IS_CANNONLAKE(dev_priv) && !IS_COFFEELAKE(dev_priv));
+		return PCH_CNP;
+	case INTEL_PCH_ICP_DEVICE_ID_TYPE:
+		DRM_DEBUG_KMS("Found Ice Lake PCH\n");
+		WARN_ON(!IS_ICELAKE(dev_priv));
+		return PCH_ICP;
+	default:
+		return PCH_NONE;
+	}
+}
 
 static enum intel_pch intel_virt_detect_pch(struct drm_i915_private *dev_priv)
 {
@@ -183,6 +252,7 @@ static void intel_detect_pch(struct drm_i915_private *dev_priv)
 	 */
 	while ((pch = pci_get_class(PCI_CLASS_BRIDGE_ISA << 8, pch))) {
 		unsigned short id;
+		enum intel_pch pch_type;
 
 		if (pch->vendor != PCI_VENDOR_ID_INTEL)
 			continue;
@@ -191,81 +261,9 @@ static void intel_detect_pch(struct drm_i915_private *dev_priv)
 
 		dev_priv->pch_id = id;
 
-		if (id == INTEL_PCH_IBX_DEVICE_ID_TYPE) {
-			dev_priv->pch_type = PCH_IBX;
-			DRM_DEBUG_KMS("Found Ibex Peak PCH\n");
-			WARN_ON(!IS_GEN5(dev_priv));
-		} else if (id == INTEL_PCH_CPT_DEVICE_ID_TYPE) {
-			dev_priv->pch_type = PCH_CPT;
-			DRM_DEBUG_KMS("Found CougarPoint PCH\n");
-			WARN_ON(!IS_GEN6(dev_priv) &&
-				!IS_IVYBRIDGE(dev_priv));
-		} else if (id == INTEL_PCH_PPT_DEVICE_ID_TYPE) {
-			/* PantherPoint is CPT compatible */
-			dev_priv->pch_type = PCH_CPT;
-			DRM_DEBUG_KMS("Found PantherPoint PCH\n");
-			WARN_ON(!IS_GEN6(dev_priv) &&
-				!IS_IVYBRIDGE(dev_priv));
-		} else if (id == INTEL_PCH_LPT_DEVICE_ID_TYPE) {
-			dev_priv->pch_type = PCH_LPT;
-			DRM_DEBUG_KMS("Found LynxPoint PCH\n");
-			WARN_ON(!IS_HASWELL(dev_priv) &&
-				!IS_BROADWELL(dev_priv));
-			WARN_ON(IS_HSW_ULT(dev_priv) ||
-				IS_BDW_ULT(dev_priv));
-		} else if (id == INTEL_PCH_LPT_LP_DEVICE_ID_TYPE) {
-			dev_priv->pch_type = PCH_LPT;
-			DRM_DEBUG_KMS("Found LynxPoint LP PCH\n");
-			WARN_ON(!IS_HASWELL(dev_priv) &&
-				!IS_BROADWELL(dev_priv));
-			WARN_ON(!IS_HSW_ULT(dev_priv) &&
-				!IS_BDW_ULT(dev_priv));
-		} else if (id == INTEL_PCH_WPT_DEVICE_ID_TYPE) {
-			/* WildcatPoint is LPT compatible */
-			dev_priv->pch_type = PCH_LPT;
-			DRM_DEBUG_KMS("Found WildcatPoint PCH\n");
-			WARN_ON(!IS_HASWELL(dev_priv) &&
-				!IS_BROADWELL(dev_priv));
-			WARN_ON(IS_HSW_ULT(dev_priv) ||
-				IS_BDW_ULT(dev_priv));
-		} else if (id == INTEL_PCH_WPT_LP_DEVICE_ID_TYPE) {
-			/* WildcatPoint is LPT compatible */
-			dev_priv->pch_type = PCH_LPT;
-			DRM_DEBUG_KMS("Found WildcatPoint LP PCH\n");
-			WARN_ON(!IS_HASWELL(dev_priv) &&
-				!IS_BROADWELL(dev_priv));
-			WARN_ON(!IS_HSW_ULT(dev_priv) &&
-				!IS_BDW_ULT(dev_priv));
-		} else if (id == INTEL_PCH_SPT_DEVICE_ID_TYPE) {
-			dev_priv->pch_type = PCH_SPT;
-			DRM_DEBUG_KMS("Found SunrisePoint PCH\n");
-			WARN_ON(!IS_SKYLAKE(dev_priv) &&
-				!IS_KABYLAKE(dev_priv));
-		} else if (id == INTEL_PCH_SPT_LP_DEVICE_ID_TYPE) {
-			dev_priv->pch_type = PCH_SPT;
-			DRM_DEBUG_KMS("Found SunrisePoint LP PCH\n");
-			WARN_ON(!IS_SKYLAKE(dev_priv) &&
-				!IS_KABYLAKE(dev_priv));
-		} else if (id == INTEL_PCH_KBP_DEVICE_ID_TYPE) {
-			dev_priv->pch_type = PCH_KBP;
-			DRM_DEBUG_KMS("Found Kaby Lake PCH (KBP)\n");
-			WARN_ON(!IS_SKYLAKE(dev_priv) &&
-				!IS_KABYLAKE(dev_priv) &&
-				!IS_COFFEELAKE(dev_priv));
-		} else if (id == INTEL_PCH_CNP_DEVICE_ID_TYPE) {
-			dev_priv->pch_type = PCH_CNP;
-			DRM_DEBUG_KMS("Found Cannon Lake PCH (CNP)\n");
-			WARN_ON(!IS_CANNONLAKE(dev_priv) &&
-				!IS_COFFEELAKE(dev_priv));
-		} else if (id == INTEL_PCH_CNP_LP_DEVICE_ID_TYPE) {
-			dev_priv->pch_type = PCH_CNP;
-			DRM_DEBUG_KMS("Found Cannon Lake LP PCH (CNP-LP)\n");
-			WARN_ON(!IS_CANNONLAKE(dev_priv) &&
-				!IS_COFFEELAKE(dev_priv));
-		} else if (id == INTEL_PCH_ICP_DEVICE_ID_TYPE) {
-			dev_priv->pch_type = PCH_ICP;
-			DRM_DEBUG_KMS("Found Ice Lake PCH\n");
-			WARN_ON(!IS_ICELAKE(dev_priv));
+		pch_type = intel_pch_type(dev_priv, id);
+		if (pch_type != PCH_NONE) {
+			dev_priv->pch_type = pch_type;
 		} else if (id == INTEL_PCH_P2X_DEVICE_ID_TYPE ||
 			   id == INTEL_PCH_P3X_DEVICE_ID_TYPE ||
 			   (id == INTEL_PCH_QEMU_DEVICE_ID_TYPE &&