drm/meson: overlay: setup overlay for Amlogic FBC Memory Saving mode

Setup the Amlogic FBC decoder for the VD1 video overlay plane to use
a different superblock size for the Memory Saving mode.
Signed-off-by: Neil Armstrong <narmstrong@baylibre.com>
Tested-by: Kevin Hilman <khilman@baylibre.com>
Reviewed-by: Kevin Hilman <khilman@baylibre.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20200703080728.25207-5-narmstrong@baylibre.com

drivers/gpu/drm/meson/meson_overlay.c

@@ -486,6 +486,10 @@ static void meson_overlay_atomic_update(struct drm_plane *plane,
 					  AFBC_HOLD_LINE_NUM(8) |
 					  AFBC_BURST_LEN(2);
 
+		if (fb->modifier & DRM_FORMAT_MOD_AMLOGIC_FBC(0,
+						AMLOGIC_FBC_OPTION_MEM_SAVING))
+			priv->viu.vd1_afbc_mode |= AFBC_BLK_MEM_MODE;
+
 		priv->viu.vd1_afbc_en = 0x1600 | AFBC_DEC_ENABLE;
 
 		priv->viu.vd1_afbc_conv_ctrl = AFBC_CONV_LBUF_LEN(256);
@@ -671,12 +675,17 @@ static void meson_overlay_atomic_update(struct drm_plane *plane,
 	}
 
 	if (priv->viu.vd1_afbc) {
+		/* Default mode is 4k per superblock */
+		unsigned long block_size = 4096;
 		unsigned long body_size;
 
-		/* Default mode is 4k per superblock */
+		/* 8bit mem saving mode is 3072bytes per superblock */
+		if (priv->viu.vd1_afbc_mode & AFBC_BLK_MEM_MODE)
+			block_size = 3072;
+
 		body_size = (ALIGN(priv->viu.vd1_stride0, 64) / 64) *
 			    (ALIGN(priv->viu.vd1_height0, 32) / 32) *
-			    4096;
+			    block_size;
 
 		priv->viu.vd1_afbc_body_addr = priv->viu.vd1_addr0 >> 4;
 
@@ -734,6 +743,9 @@ static bool meson_overlay_format_mod_supported(struct drm_plane *plane,
 		unsigned int layout = modifier &
 			DRM_FORMAT_MOD_AMLOGIC_FBC(
 				__fourcc_mod_amlogic_layout_mask, 0);
+		unsigned int options =
+			(modifier >> __fourcc_mod_amlogic_options_shift) &
+			__fourcc_mod_amlogic_options_mask;
 
 		if (format != DRM_FORMAT_YUV420_8BIT &&
 		    format != DRM_FORMAT_YUV420_10BIT) {
@@ -748,6 +760,13 @@ static bool meson_overlay_format_mod_supported(struct drm_plane *plane,
 			return false;
 		}
 
+		if (options &&
+		    options != AMLOGIC_FBC_OPTION_MEM_SAVING) {
+			DRM_DEBUG_KMS("%llx invalid layout %x\n",
+				      modifier, layout);
+			return false;
+		}
+
 		return true;
 	}
 
@@ -781,6 +800,8 @@ static const uint32_t supported_drm_formats[] = {
 };
 
 static const uint64_t format_modifiers[] = {
+	DRM_FORMAT_MOD_AMLOGIC_FBC(AMLOGIC_FBC_LAYOUT_BASIC,
+				   AMLOGIC_FBC_OPTION_MEM_SAVING),
 	DRM_FORMAT_MOD_AMLOGIC_FBC(AMLOGIC_FBC_LAYOUT_BASIC, 0),
 	DRM_FORMAT_MOD_LINEAR,
 	DRM_FORMAT_MOD_INVALID,