drm/vc4: plane: Move planes creation to its own function

The planes so far were created as part of the CRTC binding code with
each planes created associated only to one CRTC. However, the hardware
in the vc4 doesn't really have such constraint and can be used with any
CRTC.

In order to rework this, let's first move the overlay and cursor planes
creation to a function of its own.

Reviewed-by: Eric Anholt <eric@anholt.net>
Signed-off-by: Maxime Ripard <maxime@cerno.tech>
Link: https://patchwork.freedesktop.org/patch/msgid/a378ea56214179f1f25fcd36ecc69511edd1e790.1590594512.git-series.maxime@cerno.tech

1 files changed, 38 insertions, 0 deletions

diff --git a/drivers/gpu/drm/vc4/vc4_plane.c b/drivers/gpu/drm/vc4/vc4_plane.c
index 91e408f7a56e..ea559b3288f5 100644
--- a/drivers/gpu/drm/vc4/vc4_plane.c
+++ b/drivers/gpu/drm/vc4/vc4_plane.c
@@ -1267,3 +1267,41 @@ struct drm_plane *vc4_plane_init(struct drm_device *dev,
 
 	return plane;
 }
+
+int vc4_plane_create_additional_planes(struct drm_device *drm,
+				       struct drm_crtc *crtc)
+{
+	struct drm_plane *cursor_plane;
+	unsigned int i;
+
+	/* Set up some arbitrary number of planes.  We're not limited
+	 * by a set number of physical registers, just the space in
+	 * the HVS (16k) and how small an plane can be (28 bytes).
+	 * However, each plane we set up takes up some memory, and
+	 * increases the cost of looping over planes, which atomic
+	 * modesetting does quite a bit.  As a result, we pick a
+	 * modest number of planes to expose, that should hopefully
+	 * still cover any sane usecase.
+	 */
+	for (i = 0; i < 8; i++) {
+		struct drm_plane *plane =
+			vc4_plane_init(drm, DRM_PLANE_TYPE_OVERLAY);
+
+		if (IS_ERR(plane))
+			continue;
+
+		plane->possible_crtcs = drm_crtc_mask(crtc);
+	}
+
+	/* Set up the legacy cursor after overlay initialization,
+	 * since we overlay planes on the CRTC in the order they were
+	 * initialized.
+	 */
+	cursor_plane = vc4_plane_init(drm, DRM_PLANE_TYPE_CURSOR);
+	if (!IS_ERR(cursor_plane)) {
+		cursor_plane->possible_crtcs = drm_crtc_mask(crtc);
+		crtc->cursor = cursor_plane;
+	}
+
+	return 0;
+}