drm/sun4i: wait on implicit fence before display

Render like lima will attach a fence to the framebuffer
dma_buf, display like sun4i should wait it finish before
show the framebuffer. Otherwise tearing will be observed.

Signed-off-by: Qiang Yu <[e-mail]>
Signed-off-by: Daniel Vetter <[e-mail]>
Link: https://patchwork.freedesktop.org/patch/msgid/[e-mail]

drivers/gpu/drm/sun4i/sun4i_layer.c

···
 
 #include <drm/drm_atomic_helper.h>
 #include <drm/drm_plane_helper.h>
+#include <drm/drm_gem_framebuffer_helper.h>
 #include <drm/drmP.h>
 
 #include "sun4i_backend.h"
···
 }
 
 static const struct drm_plane_helper_funcs sun4i_backend_layer_helper_funcs = {
+	.prepare_fb	= drm_gem_fb_prepare_fb,
 	.atomic_disable	= sun4i_backend_layer_atomic_disable,
 	.atomic_update	= sun4i_backend_layer_atomic_update,
 };

drivers/gpu/drm/sun4i/sun8i_ui_layer.c

···
 #include <drm/drm_crtc_helper.h>
 #include <drm/drm_fb_cma_helper.h>
 #include <drm/drm_gem_cma_helper.h>
+#include <drm/drm_gem_framebuffer_helper.h>
 #include <drm/drm_plane_helper.h>
 #include <drm/drmP.h>
 
···
 }
 
 static struct drm_plane_helper_funcs sun8i_ui_layer_helper_funcs = {
+	.prepare_fb	= drm_gem_fb_prepare_fb,
 	.atomic_check	= sun8i_ui_layer_atomic_check,
 	.atomic_disable	= sun8i_ui_layer_atomic_disable,
 	.atomic_update	= sun8i_ui_layer_atomic_update,

drivers/gpu/drm/sun4i/sun8i_vi_layer.c

···
 #include <drm/drm_crtc_helper.h>
 #include <drm/drm_fb_cma_helper.h>
 #include <drm/drm_gem_cma_helper.h>
+#include <drm/drm_gem_framebuffer_helper.h>
 #include <drm/drm_plane_helper.h>
 #include <drm/drmP.h>
 
···
 }
 
 static struct drm_plane_helper_funcs sun8i_vi_layer_helper_funcs = {
+	.prepare_fb	= drm_gem_fb_prepare_fb,
 	.atomic_check	= sun8i_vi_layer_atomic_check,
 	.atomic_disable	= sun8i_vi_layer_atomic_disable,
 	.atomic_update	= sun8i_vi_layer_atomic_update,