Call drm_mode_size_dumb() to compute dumb-buffer scanline pitch and
buffer size. Align the pitch according to hardware requirements.

Signed-off-by: Thomas Zimmermann <tzimmermann@suse.de>
Cc: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Cc: Kieran Bingham <kieran.bingham+renesas@ideasonboard.com>
---
 drivers/gpu/drm/renesas/rcar-du/rcar_du_kms.c | 7 +++++--
 1 file changed, 5 insertions(+), 2 deletions(-)

diff --git a/drivers/gpu/drm/renesas/rcar-du/rcar_du_kms.c b/drivers/gpu/drm/renesas/rcar-du/rcar_du_kms.c
index 4c8fe83dd610..dd353fb858ef 100644
--- a/drivers/gpu/drm/renesas/rcar-du/rcar_du_kms.c
+++ b/drivers/gpu/drm/renesas/rcar-du/rcar_du_kms.c

@@ -11,6 +11,7 @@
 #include <drm/drm_atomic_helper.h>
 #include <drm/drm_crtc.h>
 #include <drm/drm_device.h>
+#include <drm/drm_dumb_buffers.h>
 #include <drm/drm_framebuffer.h>
 #include <drm/drm_gem_dma_helper.h>
 #include <drm/drm_gem_framebuffer_helper.h>

@@ -407,8 +408,8 @@ int rcar_du_dumb_create(struct drm_file *file, struct drm_device *dev,
 			struct drm_mode_create_dumb *args)
 {
 	struct rcar_du_device *rcdu = to_rcar_du_device(dev);
-	unsigned int min_pitch = DIV_ROUND_UP(args->width * args->bpp, 8);
 	unsigned int align;
+	int ret;
 
 	/*
 	 * The R8A7779 DU requires a 16 pixels pitch alignment as documented,

@@ -419,7 +420,9 @@ int rcar_du_dumb_create(struct drm_file *file, struct drm_device *dev,
 	else
 		align = 16 * args->bpp / 8;
 
-	args->pitch = roundup(min_pitch, align);
+	ret = drm_mode_size_dumb(dev, args, align, 0);
+	if (ret)
+		return ret;
 
 	return drm_gem_dma_dumb_create_internal(file, dev, args);
 }