[PATCH v8 11/16] drm/mediatek: Support "Pre-multiplied" blending in OVL

From: Shawn Sung
Date: Thu Jun 06 2024 - 05:45:54 EST


From: Hsiao Chien Sung <shawn.sung@xxxxxxxxxxxx>

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

Signed-off-by: Hsiao Chien Sung <shawn.sung@xxxxxxxxxxxx>
---
drivers/gpu/drm/mediatek/mtk_disp_ovl.c | 40 +++++++++++++++++++++----
1 file changed, 34 insertions(+), 6 deletions(-)

diff --git a/drivers/gpu/drm/mediatek/mtk_disp_ovl.c b/drivers/gpu/drm/mediatek/mtk_disp_ovl.c
index 54a6f11aa867..de1633988921 100644
--- a/drivers/gpu/drm/mediatek/mtk_disp_ovl.c
+++ b/drivers/gpu/drm/mediatek/mtk_disp_ovl.c
@@ -52,13 +52,16 @@
#define GMC_THRESHOLD_HIGH ((1 << GMC_THRESHOLD_BITS) / 4)
#define GMC_THRESHOLD_LOW ((1 << GMC_THRESHOLD_BITS) / 8)

+#define OVL_CON_CLRFMT_MAN BIT(23)
#define OVL_CON_BYTE_SWAP BIT(24)
-#define OVL_CON_MTX_YUV_TO_RGB (6 << 16)
+#define OVL_CON_RGB_SWAP BIT(25)
#define OVL_CON_CLRFMT_RGB (1 << 12)
#define OVL_CON_CLRFMT_RGBA8888 (2 << 12)
#define OVL_CON_CLRFMT_ARGB8888 (3 << 12)
#define OVL_CON_CLRFMT_UYVY (4 << 12)
#define OVL_CON_CLRFMT_YUYV (5 << 12)
+#define OVL_CON_MTX_YUV_TO_RGB (6 << 16)
+#define OVL_CON_CLRFMT_PARGB8888 (OVL_CON_CLRFMT_ARGB8888 | OVL_CON_CLRFMT_MAN)
#define OVL_CON_CLRFMT_RGB565(ovl) ((ovl)->data->fmt_rgb565_is_0 ? \
0 : OVL_CON_CLRFMT_RGB)
#define OVL_CON_CLRFMT_RGB888(ovl) ((ovl)->data->fmt_rgb565_is_0 ? \
@@ -72,6 +75,8 @@
#define OVL_CON_VIRT_FLIP BIT(9)
#define OVL_CON_HORZ_FLIP BIT(10)

+#define OVL_COLOR_ALPHA GENMASK(31, 24)
+
static inline bool is_10bit_rgb(u32 fmt)
{
switch (fmt) {
@@ -296,7 +301,13 @@ void mtk_ovl_config(struct device *dev, unsigned int w,
if (w != 0 && h != 0)
mtk_ddp_write_relaxed(cmdq_pkt, h << 16 | w, &ovl->cmdq_reg, ovl->regs,
DISP_REG_OVL_ROI_SIZE);
- mtk_ddp_write_relaxed(cmdq_pkt, 0x0, &ovl->cmdq_reg, ovl->regs, DISP_REG_OVL_ROI_BGCLR);
+
+ /*
+ * The background color must be opaque black (ARGB),
+ * otherwise the alpha blending will have no effect
+ */
+ mtk_ddp_write_relaxed(cmdq_pkt, OVL_COLOR_ALPHA, &ovl->cmdq_reg,
+ ovl->regs, DISP_REG_OVL_ROI_BGCLR);

mtk_ddp_write(cmdq_pkt, 0x1, &ovl->cmdq_reg, ovl->regs, DISP_REG_OVL_RST);
mtk_ddp_write(cmdq_pkt, 0x0, &ovl->cmdq_reg, ovl->regs, DISP_REG_OVL_RST);
@@ -372,7 +383,8 @@ void mtk_ovl_layer_off(struct device *dev, unsigned int idx,
DISP_REG_OVL_RDMA_CTRL(idx));
}

-static unsigned int ovl_fmt_convert(struct mtk_disp_ovl *ovl, unsigned int fmt)
+static unsigned int ovl_fmt_convert(struct mtk_disp_ovl *ovl, unsigned int fmt,
+ unsigned int blend_mode)
{
/* The return value in switch "MEM_MODE_INPUT_FORMAT_XXX"
* is defined in mediatek HW data sheet.
@@ -391,21 +403,35 @@ static unsigned int ovl_fmt_convert(struct mtk_disp_ovl *ovl, unsigned int fmt)
return OVL_CON_CLRFMT_RGB888(ovl) | OVL_CON_BYTE_SWAP;
case DRM_FORMAT_RGBX8888:
case DRM_FORMAT_RGBA8888:
+ return blend_mode == DRM_MODE_BLEND_COVERAGE ?
+ OVL_CON_CLRFMT_ARGB8888 :
+ OVL_CON_CLRFMT_PARGB8888;
case DRM_FORMAT_RGBX1010102:
case DRM_FORMAT_RGBA1010102:
return OVL_CON_CLRFMT_ARGB8888;
case DRM_FORMAT_BGRX8888:
case DRM_FORMAT_BGRA8888:
+ return OVL_CON_BYTE_SWAP |
+ (blend_mode == DRM_MODE_BLEND_COVERAGE ?
+ OVL_CON_CLRFMT_ARGB8888 :
+ OVL_CON_CLRFMT_PARGB8888);
case DRM_FORMAT_BGRX1010102:
case DRM_FORMAT_BGRA1010102:
return OVL_CON_CLRFMT_ARGB8888 | OVL_CON_BYTE_SWAP;
case DRM_FORMAT_XRGB8888:
case DRM_FORMAT_ARGB8888:
+ return blend_mode == DRM_MODE_BLEND_COVERAGE ?
+ OVL_CON_CLRFMT_RGBA8888 :
+ OVL_CON_CLRFMT_PARGB8888;
case DRM_FORMAT_XRGB2101010:
case DRM_FORMAT_ARGB2101010:
return OVL_CON_CLRFMT_RGBA8888;
case DRM_FORMAT_XBGR8888:
case DRM_FORMAT_ABGR8888:
+ return OVL_CON_RGB_SWAP |
+ (blend_mode == DRM_MODE_BLEND_COVERAGE ?
+ OVL_CON_CLRFMT_RGBA8888 :
+ OVL_CON_CLRFMT_PARGB8888);
case DRM_FORMAT_XBGR2101010:
case DRM_FORMAT_ABGR2101010:
return OVL_CON_CLRFMT_RGBA8888 | OVL_CON_BYTE_SWAP;
@@ -448,9 +474,11 @@ void mtk_ovl_layer_config(struct device *dev, unsigned int idx,
return;
}

- con = ovl_fmt_convert(ovl, fmt);
- if (state->base.fb && state->base.fb->format->has_alpha)
- con |= OVL_CON_AEN | OVL_CON_ALPHA;
+ con = ovl_fmt_convert(ovl, fmt, blend_mode);
+ if (state->base.fb) {
+ con |= OVL_CON_AEN;
+ con |= state->base.alpha & OVL_CON_ALPHA;
+ }

/* CONST_BLD must be enabled for XRGB formats although the alpha channel
* can be ignored, or OVL will still read the value from memory.
--
2.18.0