drm/i915/fbc: Split plane stride checks per-platform

Carve up stride_is_valid() into per-platform variants to
make it easier to see what limits are actually being imposed.

TODO: maybe go for vfuncs later
Reviewed-by: Juha-Pekka Heikkila <juhapekka.heikkila@gmail.com>
Reviewed-by: Vinod Govindapillai <vinod.govindapillai@intel.com>
Signed-off-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20231003194256.28569-2-ville.syrjala@linux.intel.com

drivers/gpu/drm/i915/display/intel_fbc.c

@@ -853,36 +853,70 @@ void intel_fbc_cleanup(struct drm_i915_private *i915)
 	}
 }
 
-static bool stride_is_valid(const struct intel_plane_state *plane_state)
+static bool i8xx_fbc_stride_is_valid(const struct intel_plane_state *plane_state)
 {
-	struct drm_i915_private *i915 = to_i915(plane_state->uapi.plane->dev);
 	const struct drm_framebuffer *fb = plane_state->hw.fb;
 	unsigned int stride = intel_fbc_plane_stride(plane_state) *
 		fb->format->cpp[0];
 
-	/* This should have been caught earlier. */
-	if (drm_WARN_ON_ONCE(&i915->drm, (stride & (64 - 1)) != 0))
-		return false;
+	return stride == 4096 || stride == 8192;
+}
 
-	/* Below are the additional FBC restrictions. */
-	if (stride < 512)
-		return false;
+static bool i965_fbc_stride_is_valid(const struct intel_plane_state *plane_state)
+{
+	const struct drm_framebuffer *fb = plane_state->hw.fb;
+	unsigned int stride = intel_fbc_plane_stride(plane_state) *
+		fb->format->cpp[0];
 
-	if (DISPLAY_VER(i915) == 2 || DISPLAY_VER(i915) == 3)
-		return stride == 4096 || stride == 8192;
+	return stride >= 2048 && stride <= 16384;
+}
 
-	if (DISPLAY_VER(i915) == 4 && !IS_G4X(i915) &&
-	    (stride < 2048 || stride > 16384))
-		return false;
+static bool g4x_fbc_stride_is_valid(const struct intel_plane_state *plane_state)
+{
+	return true;
+}
+
+static bool skl_fbc_stride_is_valid(const struct intel_plane_state *plane_state)
+{
+	const struct drm_framebuffer *fb = plane_state->hw.fb;
+	unsigned int stride = intel_fbc_plane_stride(plane_state) *
+		fb->format->cpp[0];
 
 	/* Display WA #1105: skl,bxt,kbl,cfl,glk */
-	if ((DISPLAY_VER(i915) == 9 || IS_GEMINILAKE(i915)) &&
-	    fb->modifier == DRM_FORMAT_MOD_LINEAR && stride & 511)
+	if (fb->modifier == DRM_FORMAT_MOD_LINEAR && stride & 511)
 		return false;
 
 	return true;
 }
 
+static bool icl_fbc_stride_is_valid(const struct intel_plane_state *plane_state)
+{
+	return true;
+}
+
+static bool stride_is_valid(const struct intel_plane_state *plane_state)
+{
+	struct drm_i915_private *i915 = to_i915(plane_state->uapi.plane->dev);
+	const struct drm_framebuffer *fb = plane_state->hw.fb;
+	unsigned int stride = intel_fbc_plane_stride(plane_state) *
+		fb->format->cpp[0];
+
+	/* This should have been caught earlier. */
+	if (drm_WARN_ON_ONCE(&i915->drm, (stride & (64 - 1)) != 0))
+		return false;
+
+	if (DISPLAY_VER(i915) >= 11)
+		return icl_fbc_stride_is_valid(plane_state);
+	else if (DISPLAY_VER(i915) >= 9)
+		return skl_fbc_stride_is_valid(plane_state);
+	else if (DISPLAY_VER(i915) >= 5 || IS_G4X(i915))
+		return g4x_fbc_stride_is_valid(plane_state);
+	else if (DISPLAY_VER(i915) == 4)
+		return i965_fbc_stride_is_valid(plane_state);
+	else
+		return i8xx_fbc_stride_is_valid(plane_state);
+}
+
 static bool pixel_format_is_valid(const struct intel_plane_state *plane_state)
 {
 	struct drm_i915_private *i915 = to_i915(plane_state->uapi.plane->dev);