drm/i915/icl: track dbuf slice-2 status

This patch adds support to start tracking status of DBUF slices.
This is foundation to introduce support for enabling/disabling second
DBUF slice dynamically for ICL.

Changes Since V1:
 - use kernel type u8 over uint8_t

Signed-off-by: Mahesh Kumar <mahesh1.kumar@intel.com>
Reviewed-by: James Ausmus <james.ausmus@intel.com>
Signed-off-by: Rodrigo Vivi <rodrigo.vivi@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20180426142517.16643-2-mahesh1.kumar@intel.com

drivers/gpu/drm/i915/i915_drv.h

@@ -1189,6 +1189,7 @@ struct skl_ddb_allocation {
 	/* packed/y */
 	struct skl_ddb_entry plane[I915_MAX_PIPES][I915_MAX_PLANES];
 	struct skl_ddb_entry uv_plane[I915_MAX_PIPES][I915_MAX_PLANES];
+	u8 enabled_slices; /* GEN11 has configurable 2 slices */
 };
 
 struct skl_ddb_values {

drivers/gpu/drm/i915/intel_display.c

@@ -11447,6 +11447,11 @@ static void verify_wm_state(struct drm_crtc *crtc,
 	skl_ddb_get_hw_state(dev_priv, &hw_ddb);
 	sw_ddb = &dev_priv->wm.skl_hw.ddb;
 
+	if (INTEL_GEN(dev_priv) >= 11)
+		if (hw_ddb.enabled_slices != sw_ddb->enabled_slices)
+			DRM_ERROR("mismatch in DBUF Slices (expected %u, got %u)\n",
+				  sw_ddb->enabled_slices,
+				  hw_ddb.enabled_slices);
 	/* planes */
 	for_each_universal_plane(dev_priv, pipe, plane) {
 		hw_plane_wm = &hw_wm.planes[plane];

drivers/gpu/drm/i915/intel_pm.c

@@ -3567,6 +3567,23 @@ bool ilk_disable_lp_wm(struct drm_device *dev)
 	return _ilk_disable_lp_wm(dev_priv, WM_DIRTY_LP_ALL);
 }
 
+static u8 intel_enabled_dbuf_slices_num(struct drm_i915_private *dev_priv)
+{
+	u8 enabled_slices;
+
+	/* Slice 1 will always be enabled */
+	enabled_slices = 1;
+
+	/* Gen prior to GEN11 have only one DBuf slice */
+	if (INTEL_GEN(dev_priv) < 11)
+		return enabled_slices;
+
+	if (I915_READ(DBUF_CTL_S2) & DBUF_POWER_STATE)
+		enabled_slices++;
+
+	return enabled_slices;
+}
+
 /*
  * FIXME: We still don't have the proper code detect if we need to apply the WA,
  * so assume we'll always need it in order to avoid underruns.
@@ -3870,6 +3887,8 @@ void skl_ddb_get_hw_state(struct drm_i915_private *dev_priv,
 
 	memset(ddb, 0, sizeof(*ddb));
 
+	ddb->enabled_slices = intel_enabled_dbuf_slices_num(dev_priv);
+
 	for_each_intel_crtc(&dev_priv->drm, crtc) {
 		enum intel_display_power_domain power_domain;
 		enum plane_id plane_id;
@@ -5088,6 +5107,7 @@ skl_copy_ddb_for_pipe(struct skl_ddb_values *dst,
 	       sizeof(dst->ddb.uv_plane[pipe]));
 	memcpy(dst->ddb.plane[pipe], src->ddb.plane[pipe],
 	       sizeof(dst->ddb.plane[pipe]));
+	dst->ddb.enabled_slices = src->ddb.enabled_slices;
 }
 
 static void

drivers/gpu/drm/i915/intel_runtime_pm.c

@@ -2656,6 +2656,8 @@ static void icl_dbuf_enable(struct drm_i915_private *dev_priv)
 	if (!(I915_READ(DBUF_CTL_S1) & DBUF_POWER_STATE) ||
 	    !(I915_READ(DBUF_CTL_S2) & DBUF_POWER_STATE))
 		DRM_ERROR("DBuf power enable timeout\n");
+	else
+		dev_priv->wm.skl_hw.ddb.enabled_slices = 2;
 }
 
 static void icl_dbuf_disable(struct drm_i915_private *dev_priv)
@@ -2669,6 +2671,8 @@ static void icl_dbuf_disable(struct drm_i915_private *dev_priv)
 	if ((I915_READ(DBUF_CTL_S1) & DBUF_POWER_STATE) ||
 	    (I915_READ(DBUF_CTL_S2) & DBUF_POWER_STATE))
 		DRM_ERROR("DBuf power disable timeout!\n");
+	else
+		dev_priv->wm.skl_hw.ddb.enabled_slices = 0;
 }
 
 static void icl_mbus_init(struct drm_i915_private *dev_priv)