drm/vc4: txp: Add horizontal and vertical size offset toggle bit

The new writeback controllers that can be found on the BCM2712 require to have their horizontal and vertical size reduced by one. Let's tie that behaviour to the compatible so we can support both the new and old controllers. Signed-off-by: Maxime Ripard <mripard@kernel.org> Link: https://patchwork.freedesktop.org/patch/msgid/20241025-drm-vc4-2712-support-v2-16-35efa83c8fc0@raspberrypi.com Signed-off-by: Dave Stevenson <dave.stevenson@raspberrypi.com>
raspberrypi · 6by9 · Sep 19, 2024 · Nov 11, 2024 · Nov 14, 2024 · Nov 14, 2024
commit b0bfdc007262a13b6a167556b681a5e6c4cba66c
diff --git a/drivers/gpu/drm/vc4/vc4_drv.h b/drivers/gpu/drm/vc4/vc4_drv.h
@@ -539,6 +539,7 @@ struct vc4_crtc_data {
 struct vc4_txp_data {
 	struct vc4_crtc_data	base;
 	unsigned int has_byte_enable:1;
+	unsigned int size_minus_one:1;
 };
 
 extern const struct vc4_txp_data bcm2835_txp_data;

diff --git a/drivers/gpu/drm/vc4/vc4_txp.c b/drivers/gpu/drm/vc4/vc4_txp.c
@@ -291,6 +291,8 @@ static void vc4_txp_connector_atomic_commit(struct drm_connector *conn,
 	struct drm_gem_dma_object *gem;
 	struct drm_display_mode *mode;
 	struct drm_framebuffer *fb;
+	unsigned int hdisplay;
+	unsigned int vdisplay;
 	u32 ctrl;
 	int idx;
 	int i;
@@ -330,9 +332,17 @@ static void vc4_txp_connector_atomic_commit(struct drm_connector *conn,
 	gem = drm_fb_dma_get_gem_obj(fb, 0);
 	TXP_WRITE(TXP_DST_PTR, gem->dma_addr + fb->offsets[0]);
 	TXP_WRITE(TXP_DST_PITCH, fb->pitches[0]);
+
+	hdisplay = mode->hdisplay ?: 1;
+	vdisplay = mode->vdisplay ?: 1;
+	if (txp_data->size_minus_one) {
+		hdisplay -= 1;
+		vdisplay -= 1;
+	}
+
 	TXP_WRITE(TXP_DIM,
-		  VC4_SET_FIELD(mode->hdisplay, TXP_WIDTH) |
-		  VC4_SET_FIELD(mode->vdisplay, TXP_HEIGHT));
+		  VC4_SET_FIELD(hdisplay, TXP_WIDTH) |
+		  VC4_SET_FIELD(vdisplay, TXP_HEIGHT));
 
 	TXP_WRITE(TXP_DST_CTRL, ctrl);