drm/i915/cnp: Add PCI ID for Cannonpoint LP PCH

The first two bytes of PCI ID for CNP_LP PCH are the same as that of
SPT_LP. We should really be looking at the first 9 bits instead of the
first 8 to identify platforms, although this seems to have not caused any
problems on earlier platforms. Introduce a 9 bit extended mask for SPT and
CNP while not touching the code for any of the other platforms.

v2: (Rodrigo) Make platform agnostic and fix commit message.

Signed-off-by: Dhinakaran Pandiyan <dhinakaran.pandiyan@intel.com>
Signed-off-by: Rodrigo Vivi <rodrigo.vivi@intel.com>
Reviewed-by: Anusha Srivatsa <anusha.srivatsa@intel.com>
Link: http://patchwork.freedesktop.org/patch/msgid/1496434004-29812-2-git-send-email-rodrigo.vivi@intel.com

drivers/gpu/drm/i915/i915_drv.c

@@ -170,6 +170,9 @@ static void intel_detect_pch(struct drm_i915_private *dev_priv)
 	while ((pch = pci_get_class(PCI_CLASS_BRIDGE_ISA << 8, pch))) {
 		if (pch->vendor == PCI_VENDOR_ID_INTEL) {
 			unsigned short id = pch->device & INTEL_PCH_DEVICE_ID_MASK;
+			unsigned short id_ext = pch->device &
+				INTEL_PCH_DEVICE_ID_MASK_EXT;
+
 			dev_priv->pch_id = id;
 
 			if (id == INTEL_PCH_IBX_DEVICE_ID_TYPE) {
@@ -206,7 +209,7 @@ static void intel_detect_pch(struct drm_i915_private *dev_priv)
 				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) {
+			} else if (id_ext == 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) &&
@@ -219,6 +222,9 @@ static void intel_detect_pch(struct drm_i915_private *dev_priv)
 			} else if (id == INTEL_PCH_CNP_DEVICE_ID_TYPE) {
 				dev_priv->pch_type = PCH_CNP;
 				DRM_DEBUG_KMS("Found CannonPoint PCH\n");
+			} else if (id_ext == INTEL_PCH_CNP_LP_DEVICE_ID_TYPE) {
+				dev_priv->pch_type = PCH_CNP;
+				DRM_DEBUG_KMS("Found CannonPoint LP PCH\n");
 			} else if ((id == INTEL_PCH_P2X_DEVICE_ID_TYPE) ||
 				   (id == INTEL_PCH_P3X_DEVICE_ID_TYPE) ||
 				   ((id == INTEL_PCH_QEMU_DEVICE_ID_TYPE) &&

drivers/gpu/drm/i915/i915_drv.h

@@ -2958,6 +2958,7 @@ intel_info(const struct drm_i915_private *dev_priv)
 #define HAS_POOLED_EU(dev_priv)	((dev_priv)->info.has_pooled_eu)
 
 #define INTEL_PCH_DEVICE_ID_MASK		0xff00
+#define INTEL_PCH_DEVICE_ID_MASK_EXT		0xff80
 #define INTEL_PCH_IBX_DEVICE_ID_TYPE		0x3b00
 #define INTEL_PCH_CPT_DEVICE_ID_TYPE		0x1c00
 #define INTEL_PCH_PPT_DEVICE_ID_TYPE		0x1e00
@@ -2967,12 +2968,15 @@ intel_info(const struct drm_i915_private *dev_priv)
 #define INTEL_PCH_SPT_LP_DEVICE_ID_TYPE		0x9D00
 #define INTEL_PCH_KBP_DEVICE_ID_TYPE		0xA200
 #define INTEL_PCH_CNP_DEVICE_ID_TYPE		0xA300
+#define INTEL_PCH_CNP_LP_DEVICE_ID_TYPE		0x9D80
 #define INTEL_PCH_P2X_DEVICE_ID_TYPE		0x7100
 #define INTEL_PCH_P3X_DEVICE_ID_TYPE		0x7000
 #define INTEL_PCH_QEMU_DEVICE_ID_TYPE		0x2900 /* qemu q35 has 2918 */
 
 #define INTEL_PCH_TYPE(dev_priv) ((dev_priv)->pch_type)
 #define HAS_PCH_CNP(dev_priv) (INTEL_PCH_TYPE(dev_priv) == PCH_CNP)
+#define HAS_PCH_CNP_LP(dev_priv) \
+	((dev_priv)->pch_id == INTEL_PCH_CNP_LP_DEVICE_ID_TYPE)
 #define HAS_PCH_KBP(dev_priv) (INTEL_PCH_TYPE(dev_priv) == PCH_KBP)
 #define HAS_PCH_SPT(dev_priv) (INTEL_PCH_TYPE(dev_priv) == PCH_SPT)
 #define HAS_PCH_LPT(dev_priv) (INTEL_PCH_TYPE(dev_priv) == PCH_LPT)