drm/amd/display: Create overlay planes

[Why]
Raven has support for combining pipes for DRM_PLANE_TYPE_OVERLAY use
but no overlays are exposed to userspace.

[How]
Expose overlay planes based on DC plane caps.

If all the pipes are in use then the atomic commits can fail, but this
is expected behavior for userspace.

Only support RGB on overlays for now.
Signed-off-by: Nicholas Kazlauskas <nicholas.kazlauskas@amd.com>
Reviewed-by: Tony Cheng <Tony.Cheng@amd.com>
Acked-by: Bhawanpreet Lakha <Bhawanpreet.Lakha@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>

drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c

@@ -1891,7 +1891,7 @@ static int amdgpu_dm_initialize_drm_device(struct amdgpu_device *adev)
 	struct amdgpu_encoder *aencoder = NULL;
 	struct amdgpu_mode_info *mode_info = &adev->mode_info;
 	uint32_t link_cnt;
-	int32_t primary_planes;
+	int32_t overlay_planes, primary_planes, total_planes;
 	enum dc_connection_type new_connection_type = dc_connection_none;
 
 	link_cnt = dm->dc->caps.max_links;
@@ -1900,9 +1900,29 @@ static int amdgpu_dm_initialize_drm_device(struct amdgpu_device *adev)
 		return -EINVAL;
 	}
 
+	/*
+	 * Determine the number of overlay planes supported.
+	 * Only support DCN for now, and cap so we don't encourage
+	 * userspace to use up all the planes.
+	 */
+	overlay_planes = 0;
+
+	for (i = 0; i < dm->dc->caps.max_planes; ++i) {
+		struct dc_plane_cap *plane = &dm->dc->caps.planes[i];
+
+		if (plane->type == DC_PLANE_TYPE_DCN_UNIVERSAL &&
+		    plane->blends_with_above && plane->blends_with_below &&
+		    plane->supports_argb8888)
+			overlay_planes += 1;
+	}
+
+	overlay_planes = min(overlay_planes, 1);
+
 	/* There is one primary plane per CRTC */
 	primary_planes = dm->dc->caps.max_streams;
-	ASSERT(primary_planes < AMDGPU_MAX_PLANES);
+
+	total_planes = primary_planes + overlay_planes;
+	ASSERT(total_planes < AMDGPU_MAX_PLANES);
 
 	/*
 	 * Initialize primary planes, implicit planes for legacy IOCTLS.
@@ -1916,6 +1936,20 @@ static int amdgpu_dm_initialize_drm_device(struct amdgpu_device *adev)
 		}
 	}
 
+	/*
+	 * Initialize overlay planes, index starting after primary planes.
+	 * These planes have a higher DRM index than the primary planes since
+	 * they should be considered as having a higher z-order.
+	 * Order is reversed to match iteration order in atomic check.
+	 */
+	for (i = (overlay_planes - 1); i >= 0; i--) {
+		if (initialize_plane(dm, mode_info, primary_planes + i,
+				     DRM_PLANE_TYPE_OVERLAY)) {
+			DRM_ERROR("KMS: Failed to initialize overlay plane\n");
+			goto fail;
+		}
+	}
+
 	for (i = 0; i < dm->dc->caps.max_streams; i++)
 		if (amdgpu_dm_crtc_init(dm, mode_info->planes[i], i)) {
 			DRM_ERROR("KMS: Failed to initialize crtc\n");
@@ -3789,9 +3823,12 @@ static const uint32_t rgb_formats[] = {
 	DRM_FORMAT_ABGR8888,
 };
 
-static const uint32_t yuv_formats[] = {
-	DRM_FORMAT_NV12,
-	DRM_FORMAT_NV21,
+static const uint32_t overlay_formats[] = {
+	DRM_FORMAT_XRGB8888,
+	DRM_FORMAT_ARGB8888,
+	DRM_FORMAT_RGBA8888,
+	DRM_FORMAT_XBGR8888,
+	DRM_FORMAT_ABGR8888,
 };
 
 static const u32 cursor_formats[] = {
@@ -3821,8 +3858,8 @@ static int amdgpu_dm_plane_init(struct amdgpu_display_manager *dm,
 				plane,
 				possible_crtcs,
 				&dm_plane_funcs,
-				yuv_formats,
-				ARRAY_SIZE(yuv_formats),
+				overlay_formats,
+				ARRAY_SIZE(overlay_formats),
 				NULL, plane->type, NULL);
 		break;
 	case DRM_PLANE_TYPE_CURSOR: