Re:[PATCH v2 2/2] drm/rockchip: vop2: Add YUV support to background color

[Andy Yan]

Hello,

At 2026-06-02 02:00:04, "Cristian Ciocaltea" <cristian.ciocaltea@xxxxxxxxxxxxx> wrote:
>The VOP2 background color must be programmed with 10-bit precision,
>using YUV format when the overlay operates in YUV mode, and RGB
>otherwise.
>
>Add the required RGB-to-YCbCr conversion logic, covering all color
>spaces supported by the display controller: BT601L, BT601F, BT709L and
>BT2020L.
>
>Since the color is currently programmed to hardware on every atomic
>commit, minimize the computation cost by splitting the work across the
>two paths: in atomic_enable(), perform the conversion unconditionally
>(the hardware state is unknown after power-on), while in atomic_flush(),
>perform it only when the DRM property has actually changed.
>
>Signed-off-by: Cristian Ciocaltea <cristian.ciocaltea@xxxxxxxxxxxxx>


    Acked-by: Andy Yan <andyshrk@xxxxxxx>

    Thanks.

>---
> drivers/gpu/drm/rockchip/rockchip_drm_vop2.c | 153 ++++++++++++++++++++++++---
> 1 file changed, 138 insertions(+), 15 deletions(-)
>
>diff --git a/drivers/gpu/drm/rockchip/rockchip_drm_vop2.c b/drivers/gpu/drm/rockchip/rockchip_drm_vop2.c
>index 64ac07cb1b0d..9b261f0c7eec 100644
>--- a/drivers/gpu/drm/rockchip/rockchip_drm_vop2.c
>+++ b/drivers/gpu/drm/rockchip/rockchip_drm_vop2.c
>@@ -728,6 +728,89 @@ static void vop2_setup_csc_mode(struct vop2_video_port *vp,
> 	vop2_win_write(win, VOP2_WIN_CSC_MODE, csc_mode);
> }
> 
>+/*
>+ * RGB-to-YCbCr conversion based on color_to_ycbcr() and rgb2ycbcr() from
>+ * drivers/media/common/v4l2-tpg/v4l2-tpg-core.c.
>+ *
>+ * Limited-range Y offset & chroma midpoint are expressed in 16-bit space.
>+ */
>+#define RGB2YUV_LIMITED_Y_OFFSET	(16 << 8)
>+#define RGB2YUV_CHROMA_OFFSET		(128 << 8)
>+#define COEFF(v, r)			((s32)(0.5 + (v) * (r) * 256.0))
>+
>+struct rgb2yuv_matrix {
>+	s32 y_r,  y_g,  y_b;
>+	s32 cb_r, cb_g, cb_b;
>+	s32 cr_r, cr_g, cr_b;
>+	s32 y_offset;
>+};
>+
>+/* BT.601 Limited range */
>+static const struct rgb2yuv_matrix rgb2yuv_bt601l = {
>+	.y_r  = COEFF(0.299, 219),   .y_g  = COEFF(0.587, 219),   .y_b  = COEFF(0.114, 219),
>+	.cb_r = COEFF(-0.1687, 224), .cb_g = COEFF(-0.3313, 224), .cb_b = COEFF(0.5, 224),
>+	.cr_r = COEFF(0.5, 224),     .cr_g = COEFF(-0.4187, 224), .cr_b = COEFF(-0.0813, 224),
>+	.y_offset = RGB2YUV_LIMITED_Y_OFFSET,
>+};
>+
>+/* BT.601 Full range */
>+static const struct rgb2yuv_matrix rgb2yuv_bt601f = {
>+	.y_r  = COEFF(0.299, 255),   .y_g  = COEFF(0.587, 255),   .y_b  = COEFF(0.114, 255),
>+	.cb_r = COEFF(-0.1687, 255), .cb_g = COEFF(-0.3313, 255), .cb_b = COEFF(0.5, 255),
>+	.cr_r = COEFF(0.5, 255),     .cr_g = COEFF(-0.4187, 255), .cr_b = COEFF(-0.0813, 255),
>+	.y_offset = 0,
>+};
>+
>+/* BT.709 Limited range */
>+static const struct rgb2yuv_matrix rgb2yuv_bt709l = {
>+	.y_r  = COEFF(0.2126, 219),  .y_g  = COEFF(0.7152, 219),  .y_b  = COEFF(0.0722, 219),
>+	.cb_r = COEFF(-0.1146, 224), .cb_g = COEFF(-0.3854, 224), .cb_b = COEFF(0.5, 224),
>+	.cr_r = COEFF(0.5, 224),     .cr_g = COEFF(-0.4542, 224), .cr_b = COEFF(-0.0458, 224),
>+	.y_offset = RGB2YUV_LIMITED_Y_OFFSET,
>+};
>+
>+/* BT.2020 Limited range */
>+static const struct rgb2yuv_matrix rgb2yuv_bt2020l = {
>+	.y_r  = COEFF(0.2627, 219),  .y_g  = COEFF(0.6780, 219),  .y_b  = COEFF(0.0593, 219),
>+	.cb_r = COEFF(-0.1396, 224), .cb_g = COEFF(-0.3604, 224), .cb_b = COEFF(0.5, 224),
>+	.cr_r = COEFF(0.5, 224),     .cr_g = COEFF(-0.4598, 224), .cr_b = COEFF(-0.0402, 224),
>+	.y_offset = RGB2YUV_LIMITED_Y_OFFSET,
>+};
>+
>+static const struct rgb2yuv_matrix *
>+vop2_rgb2yuv_get_matrix(enum vop_csc_format csc)
>+{
>+	switch (csc) {
>+	case CSC_BT601L:
>+		return &rgb2yuv_bt601l;
>+	case CSC_BT601F:
>+		return &rgb2yuv_bt601f;
>+	case CSC_BT2020L:
>+		return &rgb2yuv_bt2020l;
>+	case CSC_BT709L:
>+	default:
>+		return &rgb2yuv_bt709l;
>+	}
>+}
>+
>+/* Convert an RGB (16bpc) to YUV444 (16bpc). */
>+static void vop2_rgb16_to_yuv16(int v4l2_cs, u16 r, u16 g, u16 b,
>+				u16 *y, u16 *cb, u16 *cr)
>+{
>+	enum vop_csc_format csc = vop2_convert_csc_mode(v4l2_cs);
>+	const struct rgb2yuv_matrix *m = vop2_rgb2yuv_get_matrix(csc);
>+	s64 rs = r, gs = g, bs = b;
>+	s64 ys, cbs, crs;
>+
>+	ys  = m->y_r  * rs + m->y_g  * gs + m->y_b  * bs;
>+	cbs = m->cb_r * rs + m->cb_g * gs + m->cb_b * bs;
>+	crs = m->cr_r * rs + m->cr_g * gs + m->cr_b * bs;
>+
>+	*y  = (ys  >> 16) + m->y_offset;
>+	*cb = (cbs >> 16) + RGB2YUV_CHROMA_OFFSET;
>+	*cr = (crs >> 16) + RGB2YUV_CHROMA_OFFSET;
>+}
>+
> static void vop2_crtc_enable_irq(struct vop2_video_port *vp, u32 irq)
> {
> 	struct vop2 *vop2 = vp->vop2;
>@@ -1554,12 +1637,58 @@ static void vop2_dither_setup(struct drm_crtc *crtc, u32 *dsp_ctrl)
> 				DITHER_DOWN_ALLEGRO);
> }
> 
>-static void vop2_post_config(struct drm_crtc *crtc)
>+static void vop2_bgcolor_setup(struct drm_crtc *crtc, bool force,
>+			       struct drm_crtc_state *new_crtc_state,
>+			       struct drm_crtc_state *old_crtc_state)
>+{
>+	struct rockchip_crtc_state *new_vcstate = to_rockchip_crtc_state(new_crtc_state);
>+	struct rockchip_crtc_state *old_vcstate = to_rockchip_crtc_state(old_crtc_state);
>+	struct vop2_video_port *vp = to_vop2_video_port(crtc);
>+	u64 bgcolor = new_crtc_state->background_color;
>+	u16 y, cb, cr;
>+	u32 val;
>+
>+	if (!force && old_crtc_state->background_color == bgcolor &&
>+	    old_vcstate->color_space == new_vcstate->color_space)
>+		return;
>+
>+	/*
>+	 * Background color is programmed with 10 bits of precision, using YUV
>+	 * format when operating in YUV overlay mode, and RGB otherwise.
>+	 */
>+	if (new_vcstate->yuv_overlay) {
>+		vop2_rgb16_to_yuv16(new_vcstate->color_space,
>+				    DRM_ARGB64_GETR(bgcolor),
>+				    DRM_ARGB64_GETG(bgcolor),
>+				    DRM_ARGB64_GETB(bgcolor),
>+				    &y, &cb, &cr);
>+
>+		val = FIELD_PREP(RK3568_VP_DSP_BG__DSP_BG_RED, cr >> 6);
>+		FIELD_MODIFY(RK3568_VP_DSP_BG__DSP_BG_GREEN, &val, y >> 6);
>+		FIELD_MODIFY(RK3568_VP_DSP_BG__DSP_BG_BLUE, &val, cb >> 6);
>+	} else {
>+		/*
>+		 * Since performance is more important than accuracy here, make
>+		 * use of the DRM_ARGB64_GET*_BPCS() helpers.
>+		 */
>+		val = FIELD_PREP(RK3568_VP_DSP_BG__DSP_BG_RED,
>+				 DRM_ARGB64_GETR_BPCS(bgcolor, 10));
>+		FIELD_MODIFY(RK3568_VP_DSP_BG__DSP_BG_GREEN, &val,
>+			     DRM_ARGB64_GETG_BPCS(bgcolor, 10));
>+		FIELD_MODIFY(RK3568_VP_DSP_BG__DSP_BG_BLUE, &val,
>+			     DRM_ARGB64_GETB_BPCS(bgcolor, 10));
>+	}
>+
>+	vop2_vp_write(vp, RK3568_VP_DSP_BG, val);
>+}
>+
>+static void vop2_post_config(struct drm_crtc *crtc, bool force,
>+			     struct drm_crtc_state *new_crtc_state,
>+			     struct drm_crtc_state *old_crtc_state)
> {
> 	struct vop2_video_port *vp = to_vop2_video_port(crtc);
> 	struct vop2 *vop2 = vp->vop2;
>-	struct drm_display_mode *mode = &crtc->state->adjusted_mode;
>-	u64 bgcolor = crtc->state->background_color;
>+	struct drm_display_mode *mode = &new_crtc_state->adjusted_mode;
> 	u16 vtotal = mode->crtc_vtotal;
> 	u16 hdisplay = mode->crtc_hdisplay;
> 	u16 hact_st = mode->crtc_htotal - mode->crtc_hsync_start;
>@@ -1605,15 +1734,7 @@ static void vop2_post_config(struct drm_crtc *crtc)
> 		vop2_vp_write(vp, RK3568_VP_POST_DSP_VACT_INFO_F1, val);
> 	}
> 
>-	/*
>-	 * Background color is programmed with 10 bits of precision.
>-	 * Since performance is more important than accuracy here,
>-	 * make use of the DRM_ARGB64_GET*_BPCS() helpers.
>-	 */
>-	val = FIELD_PREP(RK3568_VP_DSP_BG__DSP_BG_RED, DRM_ARGB64_GETR_BPCS(bgcolor, 10));
>-	FIELD_MODIFY(RK3568_VP_DSP_BG__DSP_BG_GREEN, &val, DRM_ARGB64_GETG_BPCS(bgcolor, 10));
>-	FIELD_MODIFY(RK3568_VP_DSP_BG__DSP_BG_BLUE, &val, DRM_ARGB64_GETB_BPCS(bgcolor, 10));
>-	vop2_vp_write(vp, RK3568_VP_DSP_BG, val);
>+	vop2_bgcolor_setup(crtc, force, new_crtc_state, old_crtc_state);
> }
> 
> static int us_to_vertical_line(struct drm_display_mode *mode, int us)
>@@ -1628,8 +1749,9 @@ static void vop2_crtc_atomic_enable(struct drm_crtc *crtc,
> 	struct vop2 *vop2 = vp->vop2;
> 	const struct vop2_data *vop2_data = vop2->data;
> 	const struct vop2_video_port_data *vp_data = &vop2_data->vp[vp->id];
>+	struct drm_crtc_state *old_crtc_state = drm_atomic_get_old_crtc_state(state, crtc);
> 	struct drm_crtc_state *crtc_state = drm_atomic_get_new_crtc_state(state, crtc);
>-	struct rockchip_crtc_state *vcstate = to_rockchip_crtc_state(crtc->state);
>+	struct rockchip_crtc_state *vcstate = to_rockchip_crtc_state(crtc_state);
> 	struct drm_display_mode *mode = &crtc->state->adjusted_mode;
> 	unsigned long clock = mode->crtc_clock * 1000;
> 	u16 hsync_len = mode->crtc_hsync_end - mode->crtc_hsync_start;
>@@ -1799,7 +1921,7 @@ static void vop2_crtc_atomic_enable(struct drm_crtc *crtc,
> 
> 	clk_set_rate(vp->dclk, clock);
> 
>-	vop2_post_config(crtc);
>+	vop2_post_config(crtc, true, crtc_state, old_crtc_state);
> 
> 	vop2_cfg_done(vp);
> 
>@@ -1874,6 +1996,7 @@ static void vop2_crtc_atomic_flush(struct drm_crtc *crtc,
> 				   struct drm_atomic_commit *state)
> {
> 	struct drm_crtc_state *crtc_state = drm_atomic_get_new_crtc_state(state, crtc);
>+	struct drm_crtc_state *old_crtc_state = drm_atomic_get_old_crtc_state(state, crtc);
> 	struct vop2_video_port *vp = to_vop2_video_port(crtc);
> 	struct vop2 *vop2 = vp->vop2;
> 
>@@ -1881,7 +2004,7 @@ static void vop2_crtc_atomic_flush(struct drm_crtc *crtc,
> 	if (!drm_atomic_crtc_needs_modeset(crtc_state) && crtc_state->color_mgmt_changed)
> 		vop2_crtc_atomic_try_set_gamma_locked(vop2, vp, crtc, crtc_state);
> 
>-	vop2_post_config(crtc);
>+	vop2_post_config(crtc, false, crtc_state, old_crtc_state);
> 
> 	vop2_cfg_done(vp);
> 
>
>-- 
>2.54.0