drm/i915: Clean up fbc vs. plane checks

Let's record the information whether a plane can do fbc or not under
struct inte_plane.

v2: Rebase due to i9xx_plane_id
    Handle BDW/HSW correctly
v3: Move inte_fbc_init() back since we depend on it happening
    even with i915.disable_display, and populate
    fbc->possible_framebuffer_bits directly from the
    plane init code instead
v4: Add note about plane A being tied to pipe A on HSW+

Cc: Chris Wilson <chris@chris-wilson.co.uk>
Signed-off-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20180221173101.19385-1-ville.syrjala@linux.intel.com
Reviewed-by: Chris Wilson <chris@chris-wilson.co.uk>
Link: https://patchwork.freedesktop.org/patch/msgid/20180221160235.11134-5-ville.syrjala@linux.intel.com

drivers/gpu/drm/i915/intel_display.c

@@ -13215,6 +13215,32 @@ static const struct drm_plane_funcs intel_cursor_plane_funcs = {
 	.format_mod_supported = intel_cursor_plane_format_mod_supported,
 };
 
+static bool i9xx_plane_has_fbc(struct drm_i915_private *dev_priv,
+			       enum i9xx_plane_id i9xx_plane)
+{
+	if (!HAS_FBC(dev_priv))
+		return false;
+
+	if (IS_BROADWELL(dev_priv) || IS_HASWELL(dev_priv))
+		return i9xx_plane == PLANE_A; /* tied to pipe A */
+	else if (IS_IVYBRIDGE(dev_priv))
+		return i9xx_plane == PLANE_A || i9xx_plane == PLANE_B ||
+			i9xx_plane == PLANE_C;
+	else if (INTEL_GEN(dev_priv) >= 4)
+		return i9xx_plane == PLANE_A || i9xx_plane == PLANE_B;
+	else
+		return i9xx_plane == PLANE_A;
+}
+
+static bool skl_plane_has_fbc(struct drm_i915_private *dev_priv,
+			      enum pipe pipe, enum plane_id plane_id)
+{
+	if (!HAS_FBC(dev_priv))
+		return false;
+
+	return pipe == PIPE_A && plane_id == PLANE_PRIMARY;
+}
+
 static struct intel_plane *
 intel_primary_plane_create(struct drm_i915_private *dev_priv, enum pipe pipe)
 {
@@ -13257,6 +13283,21 @@ intel_primary_plane_create(struct drm_i915_private *dev_priv, enum pipe pipe)
 		primary->i9xx_plane = (enum i9xx_plane_id) pipe;
 	primary->id = PLANE_PRIMARY;
 	primary->frontbuffer_bit = INTEL_FRONTBUFFER(pipe, primary->id);
+
+	if (INTEL_GEN(dev_priv) >= 9)
+		primary->has_fbc = skl_plane_has_fbc(dev_priv,
+						     primary->pipe,
+						     primary->id);
+	else
+		primary->has_fbc = i9xx_plane_has_fbc(dev_priv,
+						      primary->i9xx_plane);
+
+	if (primary->has_fbc) {
+		struct intel_fbc *fbc = &dev_priv->fbc;
+
+		fbc->possible_framebuffer_bits |= primary->frontbuffer_bit;
+	}
+
 	primary->check_plane = intel_check_primary_plane;
 
 	if (INTEL_GEN(dev_priv) >= 9) {

drivers/gpu/drm/i915/intel_drv.h

@@ -853,6 +853,7 @@ struct intel_plane {
 	enum plane_id id;
 	enum pipe pipe;
 	bool can_scale;
+	bool has_fbc;
 	int max_downscale;
 	uint32_t frontbuffer_bit;
 

drivers/gpu/drm/i915/intel_fbc.c

@@ -46,16 +46,6 @@ static inline bool fbc_supported(struct drm_i915_private *dev_priv)
 	return HAS_FBC(dev_priv);
 }
 
-static inline bool fbc_on_pipe_a_only(struct drm_i915_private *dev_priv)
-{
-	return IS_HASWELL(dev_priv) || INTEL_GEN(dev_priv) >= 8;
-}
-
-static inline bool fbc_on_plane_a_only(struct drm_i915_private *dev_priv)
-{
-	return INTEL_GEN(dev_priv) < 4;
-}
-
 static inline bool no_fbc_on_multiple_pipes(struct drm_i915_private *dev_priv)
 {
 	return INTEL_GEN(dev_priv) <= 3;
@@ -1095,15 +1085,12 @@ void intel_fbc_choose_crtc(struct drm_i915_private *dev_priv,
 		struct intel_crtc_state *crtc_state;
 		struct intel_crtc *crtc = to_intel_crtc(plane_state->base.crtc);
 
+		if (!plane->has_fbc)
+			continue;
+
 		if (!plane_state->base.visible)
 			continue;
 
-		if (fbc_on_pipe_a_only(dev_priv) && crtc->pipe != PIPE_A)
-			continue;
-
-		if (fbc_on_plane_a_only(dev_priv) && plane->i9xx_plane != PLANE_A)
-			continue;
-
 		crtc_state = intel_atomic_get_new_crtc_state(state, crtc);
 
 		crtc_state->enable_fbc = true;
@@ -1358,7 +1345,6 @@ static bool need_fbc_vtd_wa(struct drm_i915_private *dev_priv)
 void intel_fbc_init(struct drm_i915_private *dev_priv)
 {
 	struct intel_fbc *fbc = &dev_priv->fbc;
-	enum pipe pipe;
 
 	INIT_WORK(&fbc->work.work, intel_fbc_work_fn);
 	INIT_WORK(&fbc->underrun_work, intel_fbc_underrun_work_fn);
@@ -1379,14 +1365,6 @@ void intel_fbc_init(struct drm_i915_private *dev_priv)
 		return;
 	}
 
-	for_each_pipe(dev_priv, pipe) {
-		fbc->possible_framebuffer_bits |=
-			INTEL_FRONTBUFFER(pipe, PLANE_PRIMARY);
-
-		if (fbc_on_pipe_a_only(dev_priv))
-			break;
-	}
-
 	/* This value was pulled out of someone's hat */
 	if (INTEL_GEN(dev_priv) <= 4 && !IS_GM45(dev_priv))
 		I915_WRITE(FBC_CONTROL, 500 << FBC_CTL_INTERVAL_SHIFT);