drm/vc4: crtc: Add support for a custom background color

Since a previous patch introduced the BACKGROUND_COLOR CRTC property,
which defaults to solid black, take it into account when programming the
hardware.
The exact registers used varies between the hardware generations,
but is supported by all of them.

Signed-off-by: Dave Stevenson <dave.stevenson@raspberrypi.com>

Author: 6by9

drivers/gpu/drm/vc4/vc4_crtc.c

@@ -38,6 +38,7 @@
 #include <drm/drm_atomic.h>
 #include <drm/drm_atomic_helper.h>
 #include <drm/drm_atomic_uapi.h>
+#include <drm/drm_blend.h>
 #include <drm/drm_fb_dma_helper.h>
 #include <drm/drm_framebuffer.h>
 #include <drm/drm_drv.h>
@@ -1437,6 +1438,8 @@ int __vc4_crtc_init(struct drm_device *drm,
 	if (ret)
 		return ret;
 
+	drm_crtc_attach_background_color_property(crtc);
+
 	drm_crtc_helper_add(crtc, crtc_helper_funcs);
 
 	if (vc4->gen == VC4_GEN_4) {

drivers/gpu/drm/vc4/vc4_hvs.c

@@ -1256,6 +1256,7 @@ void vc4_hvs_atomic_flush(struct drm_crtc *crtc,
 	struct vc4_crtc *vc4_crtc = to_vc4_crtc(crtc);
 	struct vc4_crtc_state *vc4_state = to_vc4_crtc_state(crtc->state);
 	unsigned int channel = vc4_state->assigned_channel;
+	u64 bgcolor = crtc->state->background_color;
 	struct drm_plane *plane;
 	struct vc4_plane_state *vc4_plane_state;
 	bool debug_dump_regs = false;
@@ -1320,16 +1321,32 @@ void vc4_hvs_atomic_flush(struct drm_crtc *crtc,
 	WARN_ON_ONCE(dlist_next - dlist_start != vc4_state->mm->mm_node.size);
 
 	if (vc4->gen >= VC4_GEN_6_C) {
-		/* This sets a black background color fill, as is the case
+		/* This sets the background color fill, as is the case
 		 * with other DRM drivers.
 		 */
+		if (vc4->gen == VC4_GEN_6_C) {
+			HVS_WRITE(SCALER6_DISPX_BGND(channel),
+				  ((bgcolor & 0xFF0000000000) >> 24) |
+				  ((bgcolor & 0xFF000000) >> 16) |
+				  ((bgcolor & 0xFF00) >> 8));
+		} else {
+			/* GEN_6_D takes a 12bit background colour */
+			HVS_WRITE(SCALER6D_DISPX_BGND0(channel),
+				  bgcolor & 0xFFF0FFF0);
+			HVS_WRITE(SCALER6D_DISPX_BGND1(channel),
+				  (bgcolor >> 32) & 0xFFF0);
+		}
 		hvs->bg_fill[channel] = enable_bg_fill;
 	} else {
 		/* we can actually run with a lower core clock when background
 		 * fill is enabled on VC4_GEN_5 so leave it enabled always.
 		 */
 		HVS_WRITE(SCALER_DISPBKGNDX(channel),
-			  HVS_READ(SCALER_DISPBKGNDX(channel)) |
+			  (HVS_READ(SCALER_DISPBKGNDX(channel)) &
+						~SCALER_DISPBKGND_FILL_COLOUR) |
+			  ((bgcolor & 0xFF0000000000) >> 24) |
+			  ((bgcolor & 0xFF000000) >> 16) |
+			  ((bgcolor & 0xFF00) >> 8) |
 			  SCALER_DISPBKGND_FILL);
 	}
 

drivers/gpu/drm/vc4/vc4_regs.h

@@ -402,6 +402,7 @@
  * opaque display planes will cover everything.
  */
 # define SCALER_DISPBKGND_FILL			BIT(24)
+# define SCALER_DISPBKGND_FILL_COLOUR		VC4_MASK(23, 0)
 
 #define SCALER_DISPSTAT0                        0x00000048
 # define SCALER_DISPSTATX_MODE_MASK		VC4_MASK(31, 30)
@@ -580,9 +581,8 @@
 # define SCALER6_DISPX_CTRL1_INTLACE		BIT(0)
 
 #define SCALER6_DISP0_BGND			0x00000038
-#define SCALER6_DISPX_BGND(x)		((hvs->vc4->gen == VC4_GEN_6_C) ? \
-	(SCALER6_DISP0_BGND + ((x) * (SCALER6_DISP1_BGND - SCALER6_DISP0_BGND))) : \
-	(SCALER6D_DISP0_BGND + ((x) * (SCALER6D_DISP1_BGND - SCALER6D_DISP0_BGND))))
+#define SCALER6_DISPX_BGND(x)		\
+	(SCALER6_DISP0_BGND + ((x) * (SCALER6_DISP1_BGND - SCALER6_DISP0_BGND)))
 
 #define SCALER6_DISP0_LPTRS			0x0000003c
 #define SCALER6_DISPX_LPTRS(x)		((hvs->vc4->gen == VC4_GEN_6_C) ? \
@@ -707,7 +707,11 @@
 #define SCALER6D_DISP0_CTRL0			0x00000100
 #define SCALER6D_DISP0_CTRL1			0x00000104
 #define SCALER6D_DISP0_BGND0			0x00000108
+#define SCALER6D_DISPX_BGND0(x)		\
+	(SCALER6D_DISP0_BGND0 + ((x) * (SCALER6D_DISP1_BGND0 - SCALER6D_DISP0_BGND0)))
 #define SCALER6D_DISP0_BGND1			0x0000010c
+#define SCALER6D_DISPX_BGND1(x)		\
+	(SCALER6D_DISP0_BGND1 + ((x) * (SCALER6D_DISP1_BGND1 - SCALER6D_DISP0_BGND1)))
 #define SCALER6D_DISP0_LPTRS			0x00000110
 #define SCALER6D_DISP0_COB			0x00000114
 #define SCALER6D_DISP0_STATUS			0x00000118