drm/i915: Add frame buffer compression on Sandybridge

Add frame buffer compression on Sandybridge. The method is similar to
Ironlake, except that two new registers of type GTTMMADR must be written
with the right fence info.

Signed-off-by: Yuanhan Liu <yuanhan.liu@linux.intel.com>
Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
diff --git a/drivers/gpu/drm/i915/i915_dma.c b/drivers/gpu/drm/i915/i915_dma.c
index e9fb895..3f7b203 100644
--- a/drivers/gpu/drm/i915/i915_dma.c
+++ b/drivers/gpu/drm/i915/i915_dma.c
@@ -1078,7 +1078,7 @@
 	if (!cfb_base)
 		goto err_fb;
 
-	if (!(IS_GM45(dev) || IS_IRONLAKE_M(dev))) {
+	if (!(IS_GM45(dev) || HAS_PCH_SPLIT(dev))) {
 		compressed_llb = drm_mm_search_free(&dev_priv->mm.stolen,
 						    4096, 4096, 0);
 		if (compressed_llb)
@@ -1096,7 +1096,7 @@
 
 	intel_disable_fbc(dev);
 	dev_priv->compressed_fb = compressed_fb;
-	if (IS_IRONLAKE_M(dev))
+	if (HAS_PCH_SPLIT(dev))
 		I915_WRITE(ILK_DPFC_CB_BASE, compressed_fb->start);
 	else if (IS_GM45(dev)) {
 		I915_WRITE(DPFC_CB_BASE, compressed_fb->start);
diff --git a/drivers/gpu/drm/i915/i915_drv.c b/drivers/gpu/drm/i915/i915_drv.c
index 5f20cd9..bdb29b2 100644
--- a/drivers/gpu/drm/i915/i915_drv.c
+++ b/drivers/gpu/drm/i915/i915_drv.c
@@ -165,6 +165,7 @@
 static const struct intel_device_info intel_sandybridge_m_info = {
 	.gen = 6, .is_mobile = 1,
 	.need_gfx_hws = 1, .has_hotplug = 1,
+	.has_fbc = 1,
 	.has_bsd_ring = 1,
 	.has_blt_ring = 1,
 };
diff --git a/drivers/gpu/drm/i915/i915_reg.h b/drivers/gpu/drm/i915/i915_reg.h
index 61ef98d..820e9df 100644
--- a/drivers/gpu/drm/i915/i915_reg.h
+++ b/drivers/gpu/drm/i915/i915_reg.h
@@ -600,6 +600,16 @@
 
 
 /*
+ * Framebuffer compression for Sandybridge
+ *
+ * The following two registers are of type GTTMMADR
+ */
+#define SNB_DPFC_CTL_SA		0x100100
+#define   SNB_CPU_FENCE_ENABLE	(1<<29)
+#define DPFC_CPU_FENCE_OFFSET	0x100104
+
+
+/*
  * GPIO regs
  */
 #define GPIOA			0x5010
diff --git a/drivers/gpu/drm/i915/intel_display.c b/drivers/gpu/drm/i915/intel_display.c
index eaf2bc6..8645a97 100644
--- a/drivers/gpu/drm/i915/intel_display.c
+++ b/drivers/gpu/drm/i915/intel_display.c
@@ -1262,6 +1262,12 @@
 	/* enable it... */
 	I915_WRITE(ILK_DPFC_CONTROL, dpfc_ctl | DPFC_CTL_EN);
 
+	if (IS_GEN6(dev)) {
+		I915_WRITE(SNB_DPFC_CTL_SA,
+			   SNB_CPU_FENCE_ENABLE | dev_priv->cfb_fence);
+		I915_WRITE(DPFC_CPU_FENCE_OFFSET, crtc->y);
+	}
+
 	DRM_DEBUG_KMS("enabled fbc on plane %d\n", intel_crtc->plane);
 }
 
@@ -6395,7 +6401,7 @@
 		dev_priv->display.dpms = i9xx_crtc_dpms;
 
 	if (I915_HAS_FBC(dev)) {
-		if (IS_IRONLAKE_M(dev)) {
+		if (HAS_PCH_SPLIT(dev)) {
 			dev_priv->display.fbc_enabled = ironlake_fbc_enabled;
 			dev_priv->display.enable_fbc = ironlake_enable_fbc;
 			dev_priv->display.disable_fbc = ironlake_disable_fbc;