drm: rcar-du: Store the number of CRTCs per group in the group structure

The number of CRTCs in a group is only used to implement plane
initialization for now, but is also needed to implement pre-association
of planes to CRTCs. Store it in the group structure instead of computing
it on demand.
Signed-off-by: Laurent Pinchart <laurent.pinchart+renesas@ideasonboard.com>

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

@@ -25,6 +25,7 @@ struct rcar_du_device;
  * @dev: the DU device
  * @mmio_offset: registers offset in the device memory map
  * @index: group index
+ * @num_crtcs: number of CRTCs in this group (1 or 2)
  * @use_count: number of users of the group (rcar_du_group_(get|put))
  * @used_crtcs: number of CRTCs currently in use
  * @lock: protects the dptsr_planes field and the DPTSR register
@@ -36,6 +37,7 @@ struct rcar_du_group {
 	unsigned int mmio_offset;
 	unsigned int index;
 
+	unsigned int num_crtcs;
 	unsigned int use_count;
 	unsigned int used_crtcs;
 

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

@@ -763,6 +763,7 @@ int rcar_du_modeset_init(struct rcar_du_device *rcdu)
 		rgrp->dev = rcdu;
 		rgrp->mmio_offset = mmio_offsets[i];
 		rgrp->index = i;
+		rgrp->num_crtcs = min(rcdu->num_crtcs - 2 * i, 2U);
 
 		/* Pre-associate all hardware planes with the first CRTC in the
 		 * group.

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

@@ -391,7 +391,6 @@ int rcar_du_planes_init(struct rcar_du_group *rgrp)
 {
 	struct rcar_du_device *rcdu = rgrp->dev;
 	unsigned int num_planes;
-	unsigned int num_crtcs;
 	unsigned int crtcs;
 	unsigned int i;
 	int ret;
@@ -399,13 +398,12 @@ int rcar_du_planes_init(struct rcar_du_group *rgrp)
 	 /* Create one primary plane per CRTC in this group and seven overlay
 	  * planes.
 	  */
-	num_crtcs = min(rcdu->num_crtcs - 2 * rgrp->index, 2U);
-	num_planes = num_crtcs + 7;
+	num_planes = rgrp->num_crtcs + 7;
 
 	crtcs = ((1 << rcdu->num_crtcs) - 1) & (3 << (2 * rgrp->index));
 
 	for (i = 0; i < num_planes; ++i) {
-		enum drm_plane_type type = i < num_crtcs
+		enum drm_plane_type type = i < rgrp->num_crtcs
 					 ? DRM_PLANE_TYPE_PRIMARY
 					 : DRM_PLANE_TYPE_OVERLAY;
 		struct rcar_du_plane *plane = &rgrp->planes[i];