[PATCH v4 06/17] drm/mediatek: Support alpha blending in OVL

[Hsiao Chien Sung <shawn.sung@mediatek.com>]

Support premultiply and coverage alpha blending in
Overlay.

Signed-off-by: Hsiao Chien Sung <shawn.sung@mediatek.com>
---
 drivers/gpu/drm/mediatek/mtk_disp_ovl.c | 73 +++++++++++++++++--------
 1 file changed, 51 insertions(+), 22 deletions(-)

diff --git a/drivers/gpu/drm/mediatek/mtk_disp_ovl.c b/drivers/gpu/drm/mediatek/mtk_disp_ovl.c
index 5aaf4342cdbd..66074c2d917c 100644
--- a/drivers/gpu/drm/mediatek/mtk_disp_ovl.c
+++ b/drivers/gpu/drm/mediatek/mtk_disp_ovl.c
@@ -39,6 +39,7 @@
 #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
@@ -52,13 +53,16 @@
 #define GMC_THRESHOLD_HIGH	((1 << GMC_THRESHOLD_BITS) / 4)
 #define GMC_THRESHOLD_LOW	((1 << GMC_THRESHOLD_BITS) / 8)
 
-#define OVL_CON_BYTE_SWAP	BIT(24)
-#define OVL_CON_MTX_YUV_TO_RGB	(6 << 16)
-#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_CLRFMT_MAN		BIT(23)
+#define OVL_CON_BYTE_SWAP		BIT(24)
+#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_PARGB8888	(OVL_CON_CLRFMT_ARGB8888 | OVL_CON_CLRFMT_MAN)
+#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_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 ? \
@@ -208,14 +212,12 @@ void mtk_ovl_clk_disable(struct device *dev)
 void mtk_ovl_start(struct device *dev)
 {
 	struct mtk_disp_ovl *ovl = dev_get_drvdata(dev);
+	unsigned int reg = readl(ovl->regs + DISP_REG_OVL_DATAPATH_CON);
 
-	if (ovl->data->smi_id_en) {
-		unsigned int reg;
+	if (ovl->data->smi_id_en)
+		reg |= OVL_LAYER_SMI_ID_EN;
 
-		reg = readl(ovl->regs + DISP_REG_OVL_DATAPATH_CON);
-		reg = reg | OVL_LAYER_SMI_ID_EN;
-		writel_relaxed(reg, ovl->regs + DISP_REG_OVL_DATAPATH_CON);
-	}
+	writel_relaxed(reg, ovl->regs + DISP_REG_OVL_DATAPATH_CON);
 	writel_relaxed(0x1, ovl->regs + DISP_REG_OVL_EN);
 }
 
@@ -274,7 +276,13 @@ 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, 0xff000000, &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);
@@ -357,7 +365,8 @@ 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.
@@ -376,18 +385,30 @@ 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 OVL_CON_CLRFMT_ARGB8888;
+		return blend_mode == DRM_MODE_BLEND_COVERAGE ?
+		       OVL_CON_CLRFMT_ARGB8888 :
+		       OVL_CON_CLRFMT_PARGB8888;
 	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_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_ARGB2101010:
 		return OVL_CON_CLRFMT_RGBA8888;
 	case DRM_FORMAT_XBGR8888:
 	case DRM_FORMAT_ABGR8888:
-		return OVL_CON_CLRFMT_RGBA8888 | OVL_CON_BYTE_SWAP;
+		return OVL_CON_RGB_SWAP |
+		       (blend_mode == DRM_MODE_BLEND_COVERAGE ?
+		       OVL_CON_CLRFMT_RGBA8888 :
+		       OVL_CON_CLRFMT_PARGB8888);
 	case DRM_FORMAT_UYVY:
 		return OVL_CON_CLRFMT_UYVY | OVL_CON_MTX_YUV_TO_RGB;
 	case DRM_FORMAT_YUYV:
@@ -408,6 +429,8 @@ 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 {
@@ -425,9 +448,15 @@ 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 (blend_mode == DRM_MODE_BLEND_PIXEL_NONE ||
+	    (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;
@@ -444,8 +473,8 @@ 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