1 files changed, 94 insertions, 12 deletions

diff --git a/drivers/gpu/drm/sun4i/sun4i_backend.c b/drivers/gpu/drm/sun4i/sun4i_backend.c
index bf49c55b0f2c..9e9255ee59cd 100644
--- a/drivers/gpu/drm/sun4i/sun4i_backend.c
+++ b/drivers/gpu/drm/sun4i/sun4i_backend.c
@@ -48,8 +48,12 @@ static const u32 sunxi_rgb2yuv_coef[12] = {
 /*
  * These coefficients are taken from the A33 BSP from Allwinner.
  *
- * The formula is for each component, each coefficient being multiplied by
- * 1024 and each constant being multiplied by 16:
+ * The first three values of each row are coded as 13-bit signed fixed-point
+ * numbers, with 10 bits for the fractional part. The fourth value is a
+ * constant coded as a 14-bit signed fixed-point number with 4 bits for the
+ * fractional part.
+ *
+ * The values in table order give the following colorspace translation:
  * G = 1.164 * Y - 0.391 * U - 0.813 * V + 135
  * R = 1.164 * Y + 1.596 * V - 222
  * B = 1.164 * Y + 2.018 * U + 276
@@ -155,6 +159,36 @@ static int sun4i_backend_drm_format_to_layer(u32 format, u32 *mode)
 	return 0;
 }
 
+static const uint32_t sun4i_backend_formats[] = {
+	DRM_FORMAT_ARGB1555,
+	DRM_FORMAT_ARGB4444,
+	DRM_FORMAT_ARGB8888,
+	DRM_FORMAT_BGRX8888,
+	DRM_FORMAT_RGB565,
+	DRM_FORMAT_RGB888,
+	DRM_FORMAT_RGBA4444,
+	DRM_FORMAT_RGBA5551,
+	DRM_FORMAT_UYVY,
+	DRM_FORMAT_VYUY,
+	DRM_FORMAT_XRGB8888,
+	DRM_FORMAT_YUYV,
+	DRM_FORMAT_YVYU,
+};
+
+bool sun4i_backend_format_is_supported(uint32_t fmt, uint64_t modifier)
+{
+	unsigned int i;
+
+	if (modifier != DRM_FORMAT_MOD_LINEAR)
+		return false;
+
+	for (i = 0; i < ARRAY_SIZE(sun4i_backend_formats); i++)
+		if (sun4i_backend_formats[i] == fmt)
+			return true;
+
+	return false;
+}
+
 int sun4i_backend_update_layer_coord(struct sun4i_backend *backend,
 				     int layer, struct drm_plane *plane)
 {
@@ -395,6 +429,15 @@ int sun4i_backend_update_layer_zpos(struct sun4i_backend *backend, int layer,
 	return 0;
 }
 
+void sun4i_backend_cleanup_layer(struct sun4i_backend *backend,
+				 int layer)
+{
+	regmap_update_bits(backend->engine.regs,
+			   SUN4I_BACKEND_ATTCTL_REG0(layer),
+			   SUN4I_BACKEND_ATTCTL_REG0_LAY_VDOEN |
+			   SUN4I_BACKEND_ATTCTL_REG0_LAY_YUVEN, 0);
+}
+
 static bool sun4i_backend_plane_uses_scaler(struct drm_plane_state *state)
 {
 	u16 src_h = state->src_h >> 16;
@@ -413,11 +456,50 @@ static bool sun4i_backend_plane_uses_frontend(struct drm_plane_state *state)
 {
 	struct sun4i_layer *layer = plane_to_sun4i_layer(state->plane);
 	struct sun4i_backend *backend = layer->backend;
+	uint32_t format = state->fb->format->format;
+	uint64_t modifier = state->fb->modifier;
 
 	if (IS_ERR(backend->frontend))
 		return false;
 
-	return sun4i_backend_plane_uses_scaler(state);
+	if (!sun4i_frontend_format_is_supported(format, modifier))
+		return false;
+
+	if (!sun4i_backend_format_is_supported(format, modifier))
+		return true;
+
+	/*
+	 * TODO: The backend alone allows 2x and 4x integer scaling, including
+	 * support for an alpha component (which the frontend doesn't support).
+	 * Use the backend directly instead of the frontend in this case, with
+	 * another test to return false.
+	 */
+
+	if (sun4i_backend_plane_uses_scaler(state))
+		return true;
+
+	/*
+	 * Here the format is supported by both the frontend and the backend
+	 * and no frontend scaling is required, so use the backend directly.
+	 */
+	return false;
+}
+
+static bool sun4i_backend_plane_is_supported(struct drm_plane_state *state,
+					     bool *uses_frontend)
+{
+	if (sun4i_backend_plane_uses_frontend(state)) {
+		*uses_frontend = true;
+		return true;
+	}
+
+	*uses_frontend = false;
+
+	/* Scaling is not supported without the frontend. */
+	if (sun4i_backend_plane_uses_scaler(state))
+		return false;
+
+	return true;
 }
 
 static void sun4i_backend_atomic_begin(struct sunxi_engine *engine,
@@ -460,14 +542,19 @@ static int sun4i_backend_atomic_check(struct sunxi_engine *engine,
 		struct drm_framebuffer *fb = plane_state->fb;
 		struct drm_format_name_buf format_name;
 
-		if (sun4i_backend_plane_uses_frontend(plane_state)) {
+		if (!sun4i_backend_plane_is_supported(plane_state,
+						      &layer_state->uses_frontend))
+			return -EINVAL;
+
+		if (layer_state->uses_frontend) {
 			DRM_DEBUG_DRIVER("Using the frontend for plane %d\n",
 					 plane->index);
-
-			layer_state->uses_frontend = true;
 			num_frontend_planes++;
 		} else {
-			layer_state->uses_frontend = false;
+			if (fb->format->is_yuv) {
+				DRM_DEBUG_DRIVER("Plane FB format is YUV\n");
+				num_yuv_planes++;
+			}
 		}
 
 		DRM_DEBUG_DRIVER("Plane FB format is %s\n",
@@ -476,11 +563,6 @@ static int sun4i_backend_atomic_check(struct sunxi_engine *engine,
 		if (fb->format->has_alpha || (plane_state->alpha != DRM_BLEND_ALPHA_OPAQUE))
 			num_alpha_planes++;
 
-		if (fb->format->is_yuv) {
-			DRM_DEBUG_DRIVER("Plane FB format is YUV\n");
-			num_yuv_planes++;
-		}
-
 		DRM_DEBUG_DRIVER("Plane zpos is %d\n",
 				 plane_state->normalized_zpos);