drm/i915: Probe for PCH chipset type

PCH is the new name for south bridge from Ironlake/Sandybridge,
which contains most of the display outputs except eDP. This one
adds a probe function to detect current PCH type, and method to
detect Cougarpoint PCH.

Signed-off-by: Zhenyu Wang <zhenyuw@linux.intel.com>
Signed-off-by: Eric Anholt <eric@anholt.net>

1 files changed, 29 insertions, 0 deletions

diff --git a/drivers/gpu/drm/i915/i915_drv.c b/drivers/gpu/drm/i915/i915_drv.c
index 0af3dcc85ce9..01e91ea5bdea 100644
--- a/drivers/gpu/drm/i915/i915_drv.c
+++ b/drivers/gpu/drm/i915/i915_drv.c
@@ -187,6 +187,35 @@ const static struct pci_device_id pciidlist[] = {
 MODULE_DEVICE_TABLE(pci, pciidlist);
 #endif
 
+#define INTEL_PCH_DEVICE_ID_MASK	0xff00
+#define INTEL_PCH_CPT_DEVICE_ID_TYPE	0x1c00
+
+void intel_detect_pch (struct drm_device *dev)
+{
+	struct drm_i915_private *dev_priv = dev->dev_private;
+	struct pci_dev *pch;
+
+	/*
+	 * The reason to probe ISA bridge instead of Dev31:Fun0 is to
+	 * make graphics device passthrough work easy for VMM, that only
+	 * need to expose ISA bridge to let driver know the real hardware
+	 * underneath. This is a requirement from virtualization team.
+	 */
+	pch = pci_get_class(PCI_CLASS_BRIDGE_ISA << 8, NULL);
+	if (pch) {
+		if (pch->vendor == PCI_VENDOR_ID_INTEL) {
+			int id;
+			id = pch->device & INTEL_PCH_DEVICE_ID_MASK;
+
+			if (id == INTEL_PCH_CPT_DEVICE_ID_TYPE) {
+				dev_priv->pch_type = PCH_CPT;
+				DRM_DEBUG_KMS("Found CougarPoint PCH\n");
+			}
+		}
+		pci_dev_put(pch);
+	}
+}
+
 static int i915_drm_freeze(struct drm_device *dev)
 {
 	struct drm_i915_private *dev_priv = dev->dev_private;