drm/mediatek: Add plumbing for layer_check hook

This allows components to implement a .layer_check callback for their
layers which is called during atomic_check.

Signed-off-by: Sean Paul <seanpaul@chromium.org>
Signed-off-by: CK Hu <ck.hu@mediatek.com>

drivers/gpu/drm/mediatek/mtk_drm_crtc.c

@@ -394,6 +394,16 @@ static void mtk_crtc_ddp_config(struct drm_crtc *crtc)
 	}
 }
 
+int mtk_drm_crtc_plane_check(struct drm_crtc *crtc, struct drm_plane *plane,
+			     struct mtk_plane_state *state)
+{
+	unsigned int local_layer;
+	struct mtk_ddp_comp *comp;
+
+	comp = mtk_drm_ddp_comp_for_plane(crtc, plane, &local_layer);
+	return mtk_ddp_comp_layer_check(comp, local_layer, state);
+}
+
 static void mtk_drm_crtc_atomic_enable(struct drm_crtc *crtc,
 				       struct drm_crtc_state *old_state)
 {

drivers/gpu/drm/mediatek/mtk_drm_crtc.h

@@ -19,5 +19,7 @@ void mtk_crtc_ddp_irq(struct drm_crtc *crtc, struct mtk_ddp_comp *comp);
 int mtk_drm_crtc_create(struct drm_device *drm_dev,
 			const enum mtk_ddp_comp_id *path,
 			unsigned int path_len);
+int mtk_drm_crtc_plane_check(struct drm_crtc *crtc, struct drm_plane *plane,
+			     struct mtk_plane_state *state);
 
 #endif /* MTK_DRM_CRTC_H */

drivers/gpu/drm/mediatek/mtk_drm_ddp_comp.h

@@ -80,6 +80,9 @@ struct mtk_ddp_comp_funcs {
 	unsigned int (*layer_nr)(struct mtk_ddp_comp *comp);
 	void (*layer_on)(struct mtk_ddp_comp *comp, unsigned int idx);
 	void (*layer_off)(struct mtk_ddp_comp *comp, unsigned int idx);
+	int (*layer_check)(struct mtk_ddp_comp *comp,
+			   unsigned int idx,
+			   struct mtk_plane_state *state);
 	void (*layer_config)(struct mtk_ddp_comp *comp, unsigned int idx,
 			     struct mtk_plane_state *state);
 	void (*gamma_set)(struct mtk_ddp_comp *comp,
@@ -152,6 +155,15 @@ static inline void mtk_ddp_comp_layer_off(struct mtk_ddp_comp *comp,
 		comp->funcs->layer_off(comp, idx);
 }
 
+static inline int mtk_ddp_comp_layer_check(struct mtk_ddp_comp *comp,
+					   unsigned int idx,
+					   struct mtk_plane_state *state)
+{
+	if (comp->funcs && comp->funcs->layer_check)
+		return comp->funcs->layer_check(comp, idx, state);
+	return 0;
+}
+
 static inline void mtk_ddp_comp_layer_config(struct mtk_ddp_comp *comp,
 					     unsigned int idx,
 					     struct mtk_plane_state *state)

drivers/gpu/drm/mediatek/mtk_drm_plane.c

@@ -90,13 +90,19 @@ static int mtk_plane_atomic_check(struct drm_plane *plane,
 {
 	struct drm_framebuffer *fb = state->fb;
 	struct drm_crtc_state *crtc_state;
+	int ret;
 
 	if (!fb)
 		return 0;
 
 	if (!state->crtc)
 		return 0;
 
+	ret = mtk_drm_crtc_plane_check(state->crtc, plane,
+				       to_mtk_plane_state(state));
+	if (ret)
+		return ret;
+
 	crtc_state = drm_atomic_get_crtc_state(state->state, state->crtc);
 	if (IS_ERR(crtc_state))
 		return PTR_ERR(crtc_state);