drm/imx: Switch to drm_fb_cma_prepare_fb() helper

Remove the common code from the driver and use the
drm_fb_cma_prepare_fb() helper instead.
Moveover, call the helper from prepare_fb() plane hook .
Signed-off-by: Marek Vasut <marex@denx.de>
Cc: Daniel Vetter <daniel.vetter@ffwll.ch>
Cc: Lucas Stach <l.stach@pengutronix.de>
Reviewed-by: Lucas Stach <l.stach@pengutronix.de>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Link: http://patchwork.freedesktop.org/patch/msgid/20161114100732.3446-2-marex@denx.de
Link: http://patchwork.freedesktop.org/patch/msgid/1476451342-146510-1-git-send-email-dvyukov@google.com

drivers/gpu/drm/imx/imx-drm-core.c

@@ -18,7 +18,6 @@
 #include <linux/dma-buf.h>
 #include <linux/module.h>
 #include <linux/platform_device.h>
-#include <linux/reservation.h>
 #include <drm/drmP.h>
 #include <drm/drm_atomic.h>
 #include <drm/drm_atomic_helper.h>
@@ -151,40 +150,11 @@ static int imx_drm_atomic_check(struct drm_device *dev,
 	return ret;
 }
 
-static int imx_drm_atomic_commit(struct drm_device *dev,
-				 struct drm_atomic_state *state,
-				 bool nonblock)
-{
-	struct drm_plane_state *plane_state;
-	struct drm_plane *plane;
-	struct dma_buf *dma_buf;
-	struct dma_fence *fence;
-	int i;
-
-	/*
-	 * If the plane fb has an dma-buf attached, fish out the exclusive
-	 * fence for the atomic helper to wait on.
-	 */
-	for_each_plane_in_state(state, plane, plane_state, i) {
-		if ((plane->state->fb != plane_state->fb) && plane_state->fb) {
-			dma_buf = drm_fb_cma_get_gem_obj(plane_state->fb,
-							 0)->base.dma_buf;
-			if (!dma_buf)
-				continue;
-			fence = reservation_object_get_excl_rcu(dma_buf->resv);
-
-			drm_atomic_set_fence_for_plane(plane_state, fence);
-		}
-	}
-
-	return drm_atomic_helper_commit(dev, state, nonblock);
-}
-
 static const struct drm_mode_config_funcs imx_drm_mode_config_funcs = {
 	.fb_create = drm_fb_cma_create,
 	.output_poll_changed = imx_drm_output_poll_changed,
 	.atomic_check = imx_drm_atomic_check,
-	.atomic_commit = imx_drm_atomic_commit,
+	.atomic_commit = drm_atomic_helper_commit,
 };
 
 static void imx_drm_atomic_commit_tail(struct drm_atomic_state *state)

drivers/gpu/drm/imx/ipuv3-plane.c

@@ -468,6 +468,7 @@ static void ipu_plane_atomic_update(struct drm_plane *plane,
 }
 
 static const struct drm_plane_helper_funcs ipu_plane_helper_funcs = {
+	.prepare_fb = drm_fb_cma_prepare_fb,
 	.atomic_check = ipu_plane_atomic_check,
 	.atomic_disable = ipu_plane_atomic_disable,
 	.atomic_update = ipu_plane_atomic_update,