backend-drm: Bind the Nth primary and cursor plane to the Nth CRTC

Some hardwares, e.g. Rockchip RK3588, allows planes to bind with other
CRTCs, but we wouldn't want to do that for primary and cursor planes.

Signed-off-by: Jeffy Chen <jeffy.chen@rock-chips.com>

libweston/backend-drm/drm-internal.h

@@ -629,6 +629,9 @@ struct drm_crtc {
 	uint32_t crtc_id; /* object ID to pass to DRM functions */
 	int pipe; /* index of CRTC in resource array / bitmasks */
 
+	uint32_t primary_plane_id; /* ID of the corresponding primary plane */
+	uint32_t cursor_plane_id; /* ID of the corresponding cursor plane */
+
 	/* Holds the properties for the CRTC */
 	struct drm_property_info props_crtc[WDRM_CRTC__COUNT];
 };

libweston/backend-drm/drm.c

@@ -187,6 +187,16 @@ drm_plane_is_available(struct drm_plane *plane, struct drm_output *output)
 	if (plane->state_cur->output && plane->state_cur->output != output)
 		return false;
 
+	/* The plane is not the primary plane for this CRTC. */
+	if (plane->type == WDRM_PLANE_TYPE_PRIMARY &&
+	    plane->plane_id != output->crtc->primary_plane_id)
+		return false;
+
+	/* The plane is not the cursor plane for this CRTC. */
+	if (plane->type == WDRM_PLANE_TYPE_CURSOR &&
+	    plane->plane_id != output->crtc->cursor_plane_id)
+		return false;
+
 	/* Check whether the plane can be used with this CRTC; possible_crtcs
 	 * is a bitmask of CRTC indices (pipe), rather than CRTC object ID. */
 	return !!(plane->possible_crtcs & (1 << output->crtc->pipe));
@@ -1253,14 +1263,16 @@ drm_plane_destroy(struct drm_plane *plane)
  * @param device DRM device
  */
 static void
-create_sprites(struct drm_device *device)
+create_sprites(struct drm_device *device, drmModeRes *resources)
 {
 	struct drm_backend *b = device->backend;
 	drmModePlaneRes *kplane_res;
 	drmModePlane *kplane;
 	struct drm_plane *drm_plane;
+	struct drm_crtc *drm_crtc;
 	uint32_t i;
 	uint32_t next_plane_idx = 0;
+	uint32_t num_primary = 0, num_cursor = 0, crtc_pipe;
 	kplane_res = drmModeGetPlaneResources(device->drm.fd);
 
 	if (!kplane_res) {
@@ -1279,10 +1291,30 @@ create_sprites(struct drm_device *device)
 		if (!drm_plane)
 			continue;
 
-		if (drm_plane->type == WDRM_PLANE_TYPE_OVERLAY)
+		/**
+		 * Assuming the Nth primary or cursor plane is for the Nth CRTC.
+		 * See:
+		 * https://lore.kernel.org/dri-devel/20200807090706.GA2352366@phenom.ffwll.local/
+		 */
+		if (drm_plane->type == WDRM_PLANE_TYPE_PRIMARY) {
+			num_primary++;
+			crtc_pipe = num_primary - 1;
+			drm_crtc = drm_crtc_find(device,
+						 resources->crtcs[crtc_pipe]);
+			assert(drm_crtc);
+			drm_crtc->primary_plane_id = drm_plane->plane_id;
+		} else if (drm_plane->type == WDRM_PLANE_TYPE_CURSOR) {
+			num_cursor++;
+			crtc_pipe = num_cursor - 1;
+			drm_crtc = drm_crtc_find(device,
+						 resources->crtcs[crtc_pipe]);
+			assert(drm_crtc);
+			drm_crtc->cursor_plane_id = drm_plane->plane_id;
+		} else if (drm_plane->type == WDRM_PLANE_TYPE_OVERLAY) {
 			weston_compositor_stack_plane(b->compositor,
 						      &drm_plane->base,
 						      NULL);
+		}
 	}
 
 	wl_list_for_each (drm_plane, &device->plane_list, link)
@@ -3786,7 +3818,7 @@ drm_device_create(struct drm_backend *backend, const char *name)
 			     WL_EVENT_READABLE, on_drm_input, device);
 
 	wl_list_init(&device->plane_list);
-	create_sprites(device);
+	create_sprites(device, res);
 
 	wl_list_init(&device->writeback_connector_list);
 	if (drm_backend_discover_connectors(device, udev_device, res) < 0) {
@@ -3973,7 +4005,7 @@ drm_backend_create(struct weston_compositor *compositor,
 	}
 
 	wl_list_init(&device->plane_list);
-	create_sprites(b->drm);
+	create_sprites(b->drm, res);
 
 	if (udev_input_init(&b->input,
 			    compositor, b->udev, seat_id,