drm/rcar-du: Fix buffer pitch alignment for R8A7790 DU

The R8A7790 DU seems to require a 128 bytes pitch alignment, even though
the documentation only mentions a 16 pixels alignement as for the
R8A7779 DU. Make this configurable through a device flag.
Signed-off-by: Laurent Pinchart <laurent.pinchart+renesas@ideasonboard.com>

drivers/gpu/drm/rcar-du/rcar_du_drv.c

@@ -221,7 +221,7 @@ static const struct rcar_du_device_info rcar_du_r8a7779_info = {
 };
 
 static const struct rcar_du_device_info rcar_du_r8a7790_info = {
-	.features = RCAR_DU_FEATURE_CRTC_IRQ_CLOCK,
+	.features = RCAR_DU_FEATURE_CRTC_IRQ_CLOCK | RCAR_DU_FEATURE_ALIGN_128B,
 };
 
 static const struct platform_device_id rcar_du_id_table[] = {

drivers/gpu/drm/rcar-du/rcar_du_drv.h

@@ -26,6 +26,7 @@ struct drm_device;
 struct rcar_du_device;
 
 #define RCAR_DU_FEATURE_CRTC_IRQ_CLOCK	(1 << 0)	/* Per-CRTC IRQ and clock */
+#define RCAR_DU_FEATURE_ALIGN_128B	(1 << 1)	/* Align pitches to 128 bytes */
 
 /*
  * struct rcar_du_device_info - DU model-specific information

drivers/gpu/drm/rcar-du/rcar_du_kms.c

@@ -111,11 +111,18 @@ const struct rcar_du_format_info *rcar_du_format_info(u32 fourcc)
 int rcar_du_dumb_create(struct drm_file *file, struct drm_device *dev,
 			struct drm_mode_create_dumb *args)
 {
+	struct rcar_du_device *rcdu = dev->dev_private;
 	unsigned int min_pitch = DIV_ROUND_UP(args->width * args->bpp, 8);
 	unsigned int align;
 
-	/* The pitch must be aligned to a 16 pixels boundary. */
+	/* The R8A7779 DU requires a 16 pixels pitch alignment as documented,
+	 * but the R8A7790 DU seems to require a 128 bytes pitch alignment.
+	 */
+	if (rcar_du_has(rcdu, RCAR_DU_FEATURE_ALIGN_128B))
+		align = 128;
+	else
 		align = 16 * args->bpp / 8;
+
 	args->pitch = roundup(max(args->pitch, min_pitch), align);
 
 	return drm_gem_cma_dumb_create(file, dev, args);
@@ -125,6 +132,7 @@ static struct drm_framebuffer *
 rcar_du_fb_create(struct drm_device *dev, struct drm_file *file_priv,
 		  struct drm_mode_fb_cmd2 *mode_cmd)
 {
+	struct rcar_du_device *rcdu = dev->dev_private;
 	const struct rcar_du_format_info *format;
 	unsigned int align;
 
@@ -135,6 +143,9 @@ rcar_du_fb_create(struct drm_device *dev, struct drm_file *file_priv,
 		return ERR_PTR(-EINVAL);
 	}
 
+	if (rcar_du_has(rcdu, RCAR_DU_FEATURE_ALIGN_128B))
+		align = 128;
+	else
 		align = 16 * format->bpp / 8;
 
 	if (mode_cmd->pitches[0] & (align - 1) ||