drm/vc4: Add support for a custom background colour

.github/workflows/kernel-build.yml

@@ -67,7 +67,7 @@ jobs:
         else
           sudo apt-get install gcc-arm-linux-gnueabihf;
         fi
-      timeout-minutes: 5
+      timeout-minutes: 10
 
     - uses: actions/checkout@v4
       with:

drivers/gpu/drm/drm_atomic_state_helper.c

@@ -74,6 +74,7 @@ __drm_atomic_helper_crtc_state_reset(struct drm_crtc_state *crtc_state,
 				     struct drm_crtc *crtc)
 {
 	crtc_state->crtc = crtc;
+	crtc_state->background_color = drm_argb64(0xffff, 0, 0, 0);
 }
 EXPORT_SYMBOL(__drm_atomic_helper_crtc_state_reset);
 

drivers/gpu/drm/drm_atomic_uapi.c

@@ -405,6 +405,8 @@ static int drm_atomic_crtc_set_property(struct drm_crtc *crtc,
 					&replaced);
 		state->color_mgmt_changed |= replaced;
 		return ret;
+	} else if (property == config->background_color_property) {
+		state->background_color = val;
 	} else if (property == config->prop_out_fence_ptr) {
 		s32 __user *fence_ptr = u64_to_user_ptr(val);
 
@@ -450,6 +452,8 @@ drm_atomic_crtc_get_property(struct drm_crtc *crtc,
 		*val = (state->ctm) ? state->ctm->base.id : 0;
 	else if (property == config->gamma_lut_property)
 		*val = (state->gamma_lut) ? state->gamma_lut->base.id : 0;
+	else if (property == config->background_color_property)
+		*val = state->background_color;
 	else if (property == config->prop_out_fence_ptr)
 		*val = 0;
 	else if (property == crtc->scaling_filter_property)

drivers/gpu/drm/drm_blend.c

@@ -185,10 +185,6 @@
  *		 plane does not expose the "alpha" property, then this is
  *		 assumed to be 1.0
  *
- * Note that all the property extensions described here apply either to the
- * plane or the CRTC (e.g. for the background color, which currently is not
- * exposed and assumed to be black).
- *
  * SCALING_FILTER:
  *     Indicates scaling filter to be used for plane scaler
  *
@@ -201,6 +197,23 @@
  *
  * Drivers can set up this property for a plane by calling
  * drm_plane_create_scaling_filter_property
+ *
+ * The property extensions described above all apply to the plane.  Drivers
+ * may also expose the following crtc property extension:
+ *
+ * BACKGROUND_COLOR:
+ *	Background color is set via drm_crtc_attach_background_color_property().
+ *	It controls the ARGB color of a full-screen layer that exists below all
+ *	planes.  This color will be used for pixels not covered by any plane and
+ *	may also be blended with plane contents as allowed by a plane's alpha
+ *	values.  The background color defaults to black, and is assumed to be
+ *	black for drivers that do not expose this property.  Although background
+ *	color isn't a plane, it is assumed that the color provided here
+ *	undergoes the same pipe-level degamma/CSC/gamma transformations that
+ *	planes undergo.  Note that the color value provided here includes an
+ *	alpha channel, hence non-opaque background color values are allowed, but
+ *	are generally only honored in special cases (e.g. when a memory
+ *	writeback connector is in use).
  */
 
 /**
@@ -648,3 +661,19 @@ int drm_plane_create_blend_mode_property(struct drm_plane *plane,
 	return 0;
 }
 EXPORT_SYMBOL(drm_plane_create_blend_mode_property);
+
+/**
+ * drm_crtc_attach_background_color_property - attach background color property
+ * @crtc: drm crtc
+ *
+ * Attaches the background color property to @crtc.  The property defaults to
+ * solid black and will accept 64-bit ARGB values in the format generated by
+ * drm_argb64().
+ */
+void drm_crtc_attach_background_color_property(struct drm_crtc *crtc)
+{
+	drm_object_attach_property(&crtc->base,
+				   crtc->dev->mode_config.background_color_property,
+				   drm_argb64(0xffff, 0, 0, 0));
+}
+EXPORT_SYMBOL(drm_crtc_attach_background_color_property);

drivers/gpu/drm/drm_mode_config.c

@@ -365,6 +365,12 @@ static int drm_mode_create_standard_properties(struct drm_device *dev)
 		return -ENOMEM;
 	dev->mode_config.gamma_lut_size_property = prop;
 
+	prop = drm_property_create_range(dev, 0,
+					 "BACKGROUND_COLOR", 0, U64_MAX);
+	if (!prop)
+		return -ENOMEM;
+	dev->mode_config.background_color_property = prop;
+
 	prop = drm_property_create(dev,
 				   DRM_MODE_PROP_IMMUTABLE | DRM_MODE_PROP_BLOB,
 				   "IN_FORMATS", 0);

drivers/gpu/drm/rockchip/rockchip_drm_vop2.c

@@ -1544,6 +1544,7 @@ static void vop2_post_config(struct drm_crtc *crtc)
 {
 	struct vop2_video_port *vp = to_vop2_video_port(crtc);
 	struct drm_display_mode *mode = &crtc->state->adjusted_mode;
+	u64 bgcolor = crtc->state->background_color;
 	u16 vtotal = mode->crtc_vtotal;
 	u16 hdisplay = mode->crtc_hdisplay;
 	u16 hact_st = mode->crtc_htotal - mode->crtc_hsync_start;
@@ -1597,7 +1598,11 @@ static void vop2_post_config(struct drm_crtc *crtc)
 		vop2_vp_write(vp, RK3568_VP_POST_DSP_VACT_INFO_F1, val);
 	}
 
-	vop2_vp_write(vp, RK3568_VP_DSP_BG, 0);
+	/* Background color is programmed with 10 bits of precision */
+	val = FIELD_PREP(RK3568_VP_DSP_BG__DSP_BG_RED, DRM_ARGB64_RED(bgcolor));
+	val |= FIELD_PREP(RK3568_VP_DSP_BG__DSP_BG_GREEN, DRM_ARGB64_GREEN(bgcolor));
+	val |= FIELD_PREP(RK3568_VP_DSP_BG__DSP_BG_BLUE, DRM_ARGB64_BLUE(bgcolor));
+	vop2_vp_write(vp, RK3568_VP_DSP_BG, val);
 }
 
 static unsigned long rk3568_set_intf_mux(struct vop2_video_port *vp, int id, u32 polflags)
@@ -2884,6 +2889,8 @@ static int vop2_create_crtcs(struct vop2 *vop2)
 			return ret;
 		}
 
+		drm_crtc_attach_background_color_property(&vp->crtc);
+
 		drm_crtc_helper_add(&vp->crtc, &vop2_crtc_helper_funcs);
 
 		init_completion(&vp->dsp_hold_completion);

drivers/gpu/drm/rockchip/rockchip_drm_vop2.h

@@ -421,6 +421,10 @@ enum dst_factor_mode {
 #define RK3588_VP_CLK_CTRL__DCLK_OUT_DIV		GENMASK(3, 2)
 #define RK3588_VP_CLK_CTRL__DCLK_CORE_DIV		GENMASK(1, 0)
 
+#define RK3568_VP_DSP_BG__DSP_BG_RED			GENMASK(29, 20)
+#define RK3568_VP_DSP_BG__DSP_BG_GREEN			GENMASK(19, 10)
+#define RK3568_VP_DSP_BG__DSP_BG_BLUE			GENMASK(9, 0)
+
 #define RK3568_VP_POST_SCL_CTRL__VSCALEDOWN		BIT(1)
 #define RK3568_VP_POST_SCL_CTRL__HSCALEDOWN		BIT(0)
 

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) ? \
@@ -698,16 +698,14 @@
 #define SCALER6D_HISTBIN7			0x000000f0
 #define SCALER6D_HVS_ID				0x000000fc
 
-#define SCALER6D_DISP0_CTRL0			0x00000100
-#define SCALER6D_DISP0_CTRL1			0x00000104
-#define SCALER6D_DISP0_BGND			0x00000108
-#define SCALER6D_DISP0_LPTRS			0x00000110
-#define SCALER6D_DISP0_COB			0x00000114
-#define SCALER6D_DISP0_STATUS			0x00000118
 #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

include/drm/drm_blend.h

@@ -31,8 +31,9 @@
 #define DRM_MODE_BLEND_COVERAGE		1
 #define DRM_MODE_BLEND_PIXEL_NONE	2
 
-struct drm_device;
 struct drm_atomic_state;
+struct drm_crtc;
+struct drm_device;
 struct drm_plane;
 struct drm_connector;
 
@@ -59,7 +60,7 @@ int drm_atomic_normalize_zpos(struct drm_device *dev,
 			      struct drm_atomic_state *state);
 int drm_plane_create_blend_mode_property(struct drm_plane *plane,
 					 unsigned int supported_modes);
-
+void drm_crtc_attach_background_color_property(struct drm_crtc *crtc);
 int drm_connector_create_rotation_property(struct drm_connector *conn,
 					   unsigned int rotation,
 					   unsigned int supported_rotations);

include/drm/drm_crtc.h

@@ -274,6 +274,18 @@ struct drm_crtc_state {
 	 */
 	struct drm_property_blob *gamma_lut;
 
+	/**
+	 * @background_color:
+	 *
+	 * RGB value representing the pipe's background color.  The background
+	 * color (aka "canvas color") of a pipe is the color that will be used
+	 * for pixels not covered by a plane, or covered by transparent pixels
+	 * of a plane.  The value here should be built using drm_argb64(), while
+	 * the individual color components can be extracted with desired
+	 * precision via the DRM_ARGB64_*() macros.
+	 */
+	u64 background_color;
+
 	/**
 	 * @target_vblank:
 	 *

include/drm/drm_mode_config.h

@@ -813,6 +813,11 @@ struct drm_mode_config {
 	 * gamma LUT as supported by the driver (read-only).
 	 */
 	struct drm_property *gamma_lut_size_property;
+	/**
+	 * @background_color_property: Optional CRTC property to set the
+	 * background color.
+	 */
+	struct drm_property *background_color_property;
 
 	/**
 	 * @suggested_x_property: Optional connector property with a hint for

include/uapi/drm/drm_mode.h

@@ -1356,6 +1356,36 @@ struct drm_mode_closefb {
 	__u32 pad;
 };
 
+/*
+ * Put 16-bit ARGB values into a standard 64-bit representation that
+ * can be used for ioctl parameters, inter-driver communication, etc.
+ */
+static inline __u64
+drm_argb64(__u16 alpha, __u16 red, __u16 green, __u16 blue)
+{
+	return (__u64)alpha << 48 | (__u64)red << 32 | (__u64)green << 16 | blue;
+}
+
+/*
+ * Extract the specified number of least-significant bits of a specific
+ * color component from a standard 64-bit ARGB value.
+ */
+#define DRM_ARGB64_COMP(c, shift, numlsb) \
+	((__u16)(((c) >> (shift)) & ((1UL << (numlsb) % 17) - 1)))
+#define DRM_ARGB64_ALPHA_LSB(c, numlsb) DRM_ARGB64_COMP(c, 48, numlsb)
+#define DRM_ARGB64_RED_LSB(c, numlsb)   DRM_ARGB64_COMP(c, 32, numlsb)
+#define DRM_ARGB64_GREEN_LSB(c, numlsb) DRM_ARGB64_COMP(c, 16, numlsb)
+#define DRM_ARGB64_BLUE_LSB(c, numlsb)  DRM_ARGB64_COMP(c, 0, numlsb)
+
+/*
+ * Convenience wrappers to extract all 16 bits of a specific color
+ * component from a standard 64-bit ARGB value.
+ */
+#define DRM_ARGB64_ALPHA(c)		DRM_ARGB64_ALPHA_LSB(c, 16)
+#define DRM_ARGB64_RED(c)		DRM_ARGB64_RED_LSB(c, 16)
+#define DRM_ARGB64_GREEN(c)		DRM_ARGB64_GREEN_LSB(c, 16)
+#define DRM_ARGB64_BLUE(c)		DRM_ARGB64_BLUE_LSB(c, 16)
+
 #if defined(__cplusplus)
 }
 #endif