drm/vc4: Advertise supported modifiers for planes

The IN_FORMATS blob allows the kernel to advertise to userspace which
format/modifier combinations are supported, per plane. Use this to
advertise that we support both T_TILED and linear.

v2:
  - Only advertise T_TILED for RGB (Eric)
  - Actually turn on allow_fb_modifiers (Eric)
Signed-off-by: Daniel Stone <daniels@collabora.com>
Signed-off-by: Eric Anholt <eric@anholt.net>
Reviewed-by: Eric Anholt <eric@anholt.net>
Link: https://patchwork.freedesktop.org/patch/170828/

drivers/gpu/drm/vc4/vc4_kms.c

@@ -215,6 +215,7 @@ int vc4_kms_load(struct drm_device *dev)
 	dev->mode_config.funcs = &vc4_mode_funcs;
 	dev->mode_config.preferred_depth = 24;
 	dev->mode_config.async_page_flip = true;
+	dev->mode_config.allow_fb_modifiers = true;
 
 	drm_mode_config_reset(dev);
 

drivers/gpu/drm/vc4/vc4_plane.c

@@ -906,6 +906,32 @@ vc4_update_plane(struct drm_plane *plane,
 					      ctx);
 }
 
+static bool vc4_format_mod_supported(struct drm_plane *plane,
+				     uint32_t format,
+				     uint64_t modifier)
+{
+	/* Support T_TILING for RGB formats only. */
+	switch (format) {
+	case DRM_FORMAT_XRGB8888:
+	case DRM_FORMAT_ARGB8888:
+	case DRM_FORMAT_ABGR8888:
+	case DRM_FORMAT_XBGR8888:
+	case DRM_FORMAT_RGB565:
+	case DRM_FORMAT_BGR565:
+	case DRM_FORMAT_ARGB1555:
+	case DRM_FORMAT_XRGB1555:
+		return true;
+	case DRM_FORMAT_YUV422:
+	case DRM_FORMAT_YVU422:
+	case DRM_FORMAT_YUV420:
+	case DRM_FORMAT_YVU420:
+	case DRM_FORMAT_NV12:
+	case DRM_FORMAT_NV16:
+	default:
+		return (modifier == DRM_FORMAT_MOD_LINEAR);
+	}
+}
+
 static const struct drm_plane_funcs vc4_plane_funcs = {
 	.update_plane = vc4_update_plane,
 	.disable_plane = drm_atomic_helper_disable_plane,
@@ -914,6 +940,7 @@ static const struct drm_plane_funcs vc4_plane_funcs = {
 	.reset = vc4_plane_reset,
 	.atomic_duplicate_state = vc4_plane_duplicate_state,
 	.atomic_destroy_state = vc4_plane_destroy_state,
+	.format_mod_supported = vc4_format_mod_supported,
 };
 
 struct drm_plane *vc4_plane_init(struct drm_device *dev,
@@ -925,6 +952,11 @@ struct drm_plane *vc4_plane_init(struct drm_device *dev,
 	u32 num_formats = 0;
 	int ret = 0;
 	unsigned i;
+	static const uint64_t modifiers[] = {
+		DRM_FORMAT_MOD_BROADCOM_VC4_T_TILED,
+		DRM_FORMAT_MOD_LINEAR,
+		DRM_FORMAT_MOD_INVALID
+	};
 
 	vc4_plane = devm_kzalloc(dev->dev, sizeof(*vc4_plane),
 				 GFP_KERNEL);
@@ -945,7 +977,7 @@ struct drm_plane *vc4_plane_init(struct drm_device *dev,
 	ret = drm_universal_plane_init(dev, plane, 0,
 				       &vc4_plane_funcs,
 				       formats, num_formats,
-				       NULL, type, NULL);
+				       modifiers, type, NULL);
 
 	drm_plane_helper_add(plane, &vc4_plane_helper_funcs);