[PATCH v6 08/14] drm/mediatek: Support "Pre-multiplied" alpha blending in OVL

[Shawn Sung <shawn.sung@mediatek.com>]

From: Hsiao Chien Sung <shawn.sung@mediatek.com>

Support "Pre-multiplied" blend mode on MediaTek's chips.
Before this patch, only the "coverage" mode is supported.

Please refer to the description of the commit
"drm/mediatek: Support alpha blending in display driver"
for more information.

Signed-off-by: Hsiao Chien Sung <shawn.sung@mediatek.com>
---
 drivers/gpu/drm/mediatek/mtk_disp_ovl.c | 84 +++++++++++++++++++++----
 1 file changed, 73 insertions(+), 11 deletions(-)

diff --git a/drivers/gpu/drm/mediatek/mtk_disp_ovl.c b/drivers/gpu/drm/mediatek/mtk_disp_ovl.c
index 2a767a823c83a..b1e5d453316cc 100644
--- a/drivers/gpu/drm/mediatek/mtk_disp_ovl.c
+++ b/drivers/gpu/drm/mediatek/mtk_disp_ovl.c
@@ -38,6 +38,7 @@
 #define DISP_REG_OVL_PITCH_MSB(n)		(0x0040 + 0x20 * (n))
 #define OVL_PITCH_MSB_2ND_SUBBUF			BIT(16)
 #define DISP_REG_OVL_PITCH(n)			(0x0044 + 0x20 * (n))
+#define OVL_CONST_BLEND					BIT(28)
 #define DISP_REG_OVL_RDMA_CTRL(n)		(0x00c0 + 0x20 * (n))
 #define DISP_REG_OVL_RDMA_GMC(n)		(0x00c8 + 0x20 * (n))
 #define DISP_REG_OVL_ADDR_MT2701		0x0040
@@ -51,13 +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 ? \
@@ -71,6 +75,24 @@
 #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) {
+	case DRM_FORMAT_XRGB2101010:
+	case DRM_FORMAT_ARGB2101010:
+	case DRM_FORMAT_RGBX1010102:
+	case DRM_FORMAT_RGBA1010102:
+	case DRM_FORMAT_XBGR2101010:
+	case DRM_FORMAT_ABGR2101010:
+	case DRM_FORMAT_BGRX1010102:
+	case DRM_FORMAT_BGRA1010102:
+		return true;
+	}
+	return false;
+}
+
 static const u32 mt8173_formats[] = {
 	DRM_FORMAT_XRGB8888,
 	DRM_FORMAT_ARGB8888,
@@ -88,12 +110,20 @@ static const u32 mt8173_formats[] = {
 static const u32 mt8195_formats[] = {
 	DRM_FORMAT_XRGB8888,
 	DRM_FORMAT_ARGB8888,
+	DRM_FORMAT_XRGB2101010,
 	DRM_FORMAT_ARGB2101010,
 	DRM_FORMAT_BGRX8888,
 	DRM_FORMAT_BGRA8888,
+	DRM_FORMAT_BGRX1010102,
 	DRM_FORMAT_BGRA1010102,
 	DRM_FORMAT_ABGR8888,
 	DRM_FORMAT_XBGR8888,
+	DRM_FORMAT_XBGR2101010,
+	DRM_FORMAT_ABGR2101010,
+	DRM_FORMAT_RGBX8888,
+	DRM_FORMAT_RGBA8888,
+	DRM_FORMAT_RGBX1010102,
+	DRM_FORMAT_RGBA1010102,
 	DRM_FORMAT_RGB888,
 	DRM_FORMAT_BGR888,
 	DRM_FORMAT_RGB565,
@@ -253,9 +283,7 @@ static void mtk_ovl_set_bit_depth(struct device *dev, int idx, u32 format,
 	reg = readl(ovl->regs + DISP_REG_OVL_CLRFMT_EXT);
 	reg &= ~OVL_CON_CLRFMT_BIT_DEPTH_MASK(idx);
 
-	if (format == DRM_FORMAT_RGBA1010102 ||
-	    format == DRM_FORMAT_BGRA1010102 ||
-	    format == DRM_FORMAT_ARGB2101010)
+	if (is_10bit_rgb(format))
 		bit_depth = OVL_CON_CLRFMT_10_BIT;
 
 	reg |= OVL_CON_CLRFMT_BIT_DEPTH(bit_depth, idx);
@@ -273,7 +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 should be opaque black (ARGB),
+	 * otherwise there will be no effect with alpha blend
+	 */
+	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);
@@ -353,7 +387,8 @@ 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.
@@ -372,17 +407,37 @@ 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;
 	case DRM_FORMAT_UYVY:
 		return OVL_CON_CLRFMT_UYVY | OVL_CON_MTX_YUV_TO_RGB;
@@ -404,6 +459,8 @@ void mtk_ovl_layer_config(struct device *dev, unsigned int idx,
 	unsigned int fmt = pending->format;
 	unsigned int offset = (pending->y << 16) | pending->x;
 	unsigned int src_size = (pending->height << 16) | pending->width;
+	unsigned int blend_mode = state->base.pixel_blend_mode;
+	unsigned int ignore_pixel_alpha = 0;
 	unsigned int con;
 	bool is_afbc = pending->modifier != DRM_FORMAT_MOD_LINEAR;
 	union overlay_pitch {
@@ -421,9 +478,14 @@ 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;
+	}
+
+	if (state->base.fb && !state->base.fb->format->has_alpha)
+		ignore_pixel_alpha = OVL_CONST_BLEND;
 
 	if (pending->rotation & DRM_MODE_REFLECT_Y) {
 		con |= OVL_CON_VIRT_FLIP;
@@ -440,8 +502,8 @@ void mtk_ovl_layer_config(struct device *dev, unsigned int idx,
 
 	mtk_ddp_write_relaxed(cmdq_pkt, con, &ovl->cmdq_reg, ovl->regs,
 			      DISP_REG_OVL_CON(idx));
-	mtk_ddp_write_relaxed(cmdq_pkt, overlay_pitch.split_pitch.lsb, &ovl->cmdq_reg, ovl->regs,
-			      DISP_REG_OVL_PITCH(idx));
+	mtk_ddp_write_relaxed(cmdq_pkt, overlay_pitch.split_pitch.lsb | ignore_pixel_alpha,
+			      &ovl->cmdq_reg, ovl->regs, DISP_REG_OVL_PITCH(idx));
 	mtk_ddp_write_relaxed(cmdq_pkt, src_size, &ovl->cmdq_reg, ovl->regs,
 			      DISP_REG_OVL_SRC_SIZE(idx));
 	mtk_ddp_write_relaxed(cmdq_pkt, offset, &ovl->cmdq_reg, ovl->regs,
-- 
2.18.0