drm/mediatek: Support "Pre-multiplied" blending in Mixer

Support "Pre-multiplied" alpha blending mode in Mixer.
Before this patch, only the coverage mode is supported.

To replace the default setting that is set in mtk_ethdr_config(),
we change mtk_ddp_write_mask() to mtk_ddp_write(), and this change will
also reset the NON_PREMULTI_SOURCE bit that was assigned in
mtk_ethdr_config(). Therefore, we must still set NON_PREMULTI_SOURCE bit
if the blend mode is not DRM_MODE_BLEND_PREMULTI.

Reviewed-by: AngeloGioacchino Del Regno <angelogioacchino.delregno@collabora.com>
Signed-off-by: Hsiao Chien Sung <shawn.sung@mediatek.com>
Reviewed-by: CK Hu <ck.hu@mediatek.com>
Link: https://patchwork.kernel.org/project/dri-devel/patch/20240717-alpha-blending-v4-4-4b1c806c0749@mediatek.com/
Signed-off-by: Chun-Kuang Hu <chunkuang.hu@kernel.org>

diff --git a/drivers/gpu/drm/mediatek/mtk_ethdr.c b/drivers/gpu/drm/mediatek/mtk_ethdr.c
index 80ccdad3741bdbe09a650dbc743b623d71e79ff4..d1d9cf8b10e16d0b4db8a9e7e79592128735863e 100644 (file)
--- a/drivers/gpu/drm/mediatek/mtk_ethdr.c
+++ b/drivers/gpu/drm/mediatek/mtk_ethdr.c
@@ -36,6 +36,7 @@
 #define MIX_SRC_L0_EN                          BIT(0)
 #define MIX_L_SRC_CON(n)               (0x28 + 0x18 * (n))
 #define NON_PREMULTI_SOURCE                    (2 << 12)
+#define PREMULTI_SOURCE                                (3 << 12)
 #define MIX_L_SRC_SIZE(n)              (0x30 + 0x18 * (n))
 #define MIX_L_SRC_OFFSET(n)            (0x34 + 0x18 * (n))
 #define MIX_FUNC_DCM0                  0x120
@@ -176,6 +177,11 @@ void mtk_ethdr_layer_config(struct device *dev, unsigned int idx,
                alpha_con |= state->base.alpha & MIXER_ALPHA;
        }
 
+       if (state->base.pixel_blend_mode == DRM_MODE_BLEND_PREMULTI)
+               alpha_con |= PREMULTI_SOURCE;
+       else
+               alpha_con |= NON_PREMULTI_SOURCE;
+
        if ((state->base.fb && !state->base.fb->format->has_alpha) ||
            state->base.pixel_blend_mode == DRM_MODE_BLEND_PIXEL_NONE) {
                /*
@@ -193,8 +199,7 @@ void mtk_ethdr_layer_config(struct device *dev, unsigned int idx,
        mtk_ddp_write(cmdq_pkt, pending->height << 16 | align_width, &mixer->cmdq_base,
                      mixer->regs, MIX_L_SRC_SIZE(idx));
        mtk_ddp_write(cmdq_pkt, offset, &mixer->cmdq_base, mixer->regs, MIX_L_SRC_OFFSET(idx));
-       mtk_ddp_write_mask(cmdq_pkt, alpha_con, &mixer->cmdq_base, mixer->regs, MIX_L_SRC_CON(idx),
-                          0x1ff);
+       mtk_ddp_write(cmdq_pkt, alpha_con, &mixer->cmdq_base, mixer->regs, MIX_L_SRC_CON(idx));
        mtk_ddp_write_mask(cmdq_pkt, BIT(idx), &mixer->cmdq_base, mixer->regs, MIX_SRC_CON,
                           BIT(idx));
 }