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>

drivers/gpu/drm/i915/i915_dma.c

@@ -1078,7 +1078,7 @@ static void i915_setup_compression(struct drm_device *dev, int size)
 	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 @@ static void i915_setup_compression(struct drm_device *dev, int size)
 
 	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);

drivers/gpu/drm/i915/i915_drv.c

@@ -165,6 +165,7 @@ static const struct intel_device_info intel_sandybridge_d_info = {
 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,
 };

drivers/gpu/drm/i915/i915_reg.h

@@ -599,6 +599,16 @@
 #define   ILK_PABSTRETCH_DIS 	(1<<21)
 
 
+/*
+ * 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
  */

drivers/gpu/drm/i915/intel_display.c

@@ -1262,6 +1262,12 @@ static void ironlake_enable_fbc(struct drm_crtc *crtc, unsigned long interval)
 	/* 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 @@ static void intel_init_display(struct drm_device *dev)
 		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;