drm/msm/dpu: revise timing engine programming to support widebus feature

Widebus feature will transmit two pixel data per pixel clock to interface.
Timing engine provides driving force for this purpose. This patch base
on HPG (Hardware Programming Guide) to revise timing engine register
setting to accommodate both widebus and non widebus application. Also
horizontal width parameters need to be reduced by half since two pixel
data are clocked out per pixel clock when widebus feature enabled.

Widebus can be enabled individually at DP. However at DSI, widebus have
to be enabled along with DSC to achieve pixel clock rate be scaled down
with same ratio as compression ratio when 10 bits per source component.
Therefore this patch add no supports of DSI related widebus and compression.

Changes in v2:
-- remove compression related code from timing
-- remove op_info from  struct msm_drm_private
-- remove unnecessary wide_bus_en variables
-- pass wide_bus_en into timing configuration by struct msm_dp

Changes in v3:
-- split patch into 3 patches

Changes in v4:
-- rework timing engine to not interfere with dsi/hdmi
-- cover both widebus and compression

Changes in v5:
-- remove supports of DSI widebus and compression

Changes in v7:
-- split this patch into 3 patches
-- add Tested-by

Changes in v8:
-- move new registers writes under DATA_HCTL_EN features check.

Changes in v10:
-- add const inside dpu_encoder_is_widebus_enabled()
-- drop useless parenthesis please

Signed-off-by: Kuogee Hsieh <quic_khsieh@quicinc.com>
Tested-by: Bjorn Andersson <bjorn.andersson@linaro.org>
Reviewed-by: Dmitry Baryshkov <dmitry.baryshkov@linaro.org>
Reviewed-by: Stephen Boyd <swboyd@chromium.org>
Patchwork: https://patchwork.freedesktop.org/patch/476281/
Link: https://lore.kernel.org/r/1645824192-29670-4-git-send-email-quic_khsieh@quicinc.com
Signed-off-by: Dmitry Baryshkov <dmitry.baryshkov@linaro.org>

drivers/gpu/drm/msm/disp/dpu1/dpu_encoder.c

@@ -206,6 +206,8 @@ struct dpu_encoder_virt {
 	struct msm_display_topology topology;
 
 	u32 idle_timeout;
+
+	bool wide_bus_en;
 };
 
 #define to_dpu_encoder_virt(x) container_of(x, struct dpu_encoder_virt, base)
@@ -214,6 +216,14 @@ static u32 dither_matrix[DITHER_MATRIX_SZ] = {
 	15, 7, 13, 5, 3, 11, 1, 9, 12, 4, 14, 6, 0, 8, 2, 10
 };
 
+
+bool dpu_encoder_is_widebus_enabled(const struct drm_encoder *drm_enc)
+{
+	const struct dpu_encoder_virt *dpu_enc = to_dpu_encoder_virt(drm_enc);
+
+	return dpu_enc->wide_bus_en;
+}
+
 static void _dpu_encoder_setup_dither(struct dpu_hw_pingpong *hw_pp, unsigned bpc)
 {
 	struct dpu_hw_dither_cfg dither_cfg = { 0 };

drivers/gpu/drm/msm/disp/dpu1/dpu_encoder.h

@@ -170,4 +170,6 @@ int dpu_encoder_get_linecount(struct drm_encoder *drm_enc);
  */
 int dpu_encoder_get_vsync_count(struct drm_encoder *drm_enc);
 
+bool dpu_encoder_is_widebus_enabled(const struct drm_encoder *drm_enc);
+
 #endif /* __DPU_ENCODER_H__ */

drivers/gpu/drm/msm/disp/dpu1/dpu_encoder_phys_vid.c

@@ -110,6 +110,20 @@ static void drm_mode_to_intf_timing_params(
 		timing->v_back_porch += timing->v_front_porch;
 		timing->v_front_porch = 0;
 	}
+
+	timing->wide_bus_en = dpu_encoder_is_widebus_enabled(phys_enc->parent);
+
+	/*
+	 * for DP, divide the horizonal parameters by 2 when
+	 * widebus is enabled
+	 */
+	if (phys_enc->hw_intf->cap->type == INTF_DP && timing->wide_bus_en) {
+		timing->width = timing->width >> 1;
+		timing->xres = timing->xres >> 1;
+		timing->h_back_porch = timing->h_back_porch >> 1;
+		timing->h_front_porch = timing->h_front_porch >> 1;
+		timing->hsync_pulse_width = timing->hsync_pulse_width >> 1;
+	}
 }
 
 static u32 get_horizontal_total(const struct intf_timing_params *timing)

drivers/gpu/drm/msm/disp/dpu1/dpu_hw_intf.c

@@ -33,6 +33,7 @@
 #define INTF_TP_COLOR1                  0x05C
 #define INTF_CONFIG2                    0x060
 #define INTF_DISPLAY_DATA_HCTL          0x064
+#define INTF_ACTIVE_DATA_HCTL           0x068
 #define INTF_FRAME_LINE_COUNT_EN        0x0A8
 #define INTF_FRAME_COUNT                0x0AC
 #define   INTF_LINE_COUNT               0x0B0
@@ -96,15 +97,23 @@ static void dpu_hw_intf_setup_timing_engine(struct dpu_hw_intf *ctx,
 	u32 hsync_period, vsync_period;
 	u32 display_v_start, display_v_end;
 	u32 hsync_start_x, hsync_end_x;
+	u32 hsync_data_start_x, hsync_data_end_x;
 	u32 active_h_start, active_h_end;
 	u32 active_v_start, active_v_end;
 	u32 active_hctl, display_hctl, hsync_ctl;
 	u32 polarity_ctl, den_polarity, hsync_polarity, vsync_polarity;
 	u32 panel_format;
-	u32 intf_cfg, intf_cfg2 = 0, display_data_hctl = 0;
+	u32 intf_cfg, intf_cfg2 = 0;
+	u32 display_data_hctl = 0, active_data_hctl = 0;
+	u32 data_width;
+	bool dp_intf = false;
 
 	/* read interface_cfg */
 	intf_cfg = DPU_REG_READ(c, INTF_CONFIG);
+
+	if (ctx->cap->type == INTF_EDP || ctx->cap->type == INTF_DP)
+		dp_intf = true;
+
 	hsync_period = p->hsync_pulse_width + p->h_back_porch + p->width +
 	p->h_front_porch;
 	vsync_period = p->vsync_pulse_width + p->v_back_porch + p->height +
@@ -118,7 +127,7 @@ static void dpu_hw_intf_setup_timing_engine(struct dpu_hw_intf *ctx,
 	hsync_start_x = p->h_back_porch + p->hsync_pulse_width;
 	hsync_end_x = hsync_period - p->h_front_porch - 1;
 
-	if (p->width != p->xres) {
+	if (p->width != p->xres) { /* border fill added */
 		active_h_start = hsync_start_x;
 		active_h_end = active_h_start + p->xres - 1;
 	} else {
@@ -126,7 +135,7 @@ static void dpu_hw_intf_setup_timing_engine(struct dpu_hw_intf *ctx,
 		active_h_end = 0;
 	}
 
-	if (p->height != p->yres) {
+	if (p->height != p->yres) { /* border fill added */
 		active_v_start = display_v_start;
 		active_v_end = active_v_start + (p->yres * hsync_period) - 1;
 	} else {
@@ -147,17 +156,35 @@ static void dpu_hw_intf_setup_timing_engine(struct dpu_hw_intf *ctx,
 	hsync_ctl = (hsync_period << 16) | p->hsync_pulse_width;
 	display_hctl = (hsync_end_x << 16) | hsync_start_x;
 
-	if (ctx->cap->type == INTF_EDP || ctx->cap->type == INTF_DP) {
+	/*
+	 * DATA_HCTL_EN controls data timing which can be different from
+	 * video timing. It is recommended to enable it for all cases, except
+	 * if compression is enabled in 1 pixel per clock mode
+	 */
+	if (p->wide_bus_en)
+		intf_cfg2 |= INTF_CFG2_DATABUS_WIDEN | INTF_CFG2_DATA_HCTL_EN;
+
+	data_width = p->width;
+
+	hsync_data_start_x = hsync_start_x;
+	hsync_data_end_x =  hsync_start_x + data_width - 1;
+
+	display_data_hctl = (hsync_data_end_x << 16) | hsync_data_start_x;
+
+	if (dp_intf) {
+		/* DP timing adjustment */
+		display_v_start += p->hsync_pulse_width + p->h_back_porch;
+		display_v_end   -= p->h_front_porch;
+
 		active_h_start = hsync_start_x;
 		active_h_end = active_h_start + p->xres - 1;
 		active_v_start = display_v_start;
 		active_v_end = active_v_start + (p->yres * hsync_period) - 1;
 
-		display_v_start += p->hsync_pulse_width + p->h_back_porch;
-		display_v_end   -= p->h_front_porch; 
-
 		active_hctl = (active_h_end << 16) | active_h_start;
 		display_hctl = active_hctl;
+
+		intf_cfg |= INTF_CFG_ACTIVE_H_EN | INTF_CFG_ACTIVE_V_EN;
 	}
 
 	den_polarity = 0;
@@ -187,13 +214,6 @@ static void dpu_hw_intf_setup_timing_engine(struct dpu_hw_intf *ctx,
 				(COLOR_8BIT << 4) |
 				(0x21 << 8));
 
-	if (ctx->cap->features & BIT(DPU_DATA_HCTL_EN)) {
-		intf_cfg2 |= INTF_CFG2_DATA_HCTL_EN;
-		display_data_hctl = display_hctl;
-		DPU_REG_WRITE(c, INTF_CONFIG2, intf_cfg2);
-		DPU_REG_WRITE(c, INTF_DISPLAY_DATA_HCTL, display_data_hctl);
-	}
-
 	DPU_REG_WRITE(c, INTF_HSYNC_CTL, hsync_ctl);
 	DPU_REG_WRITE(c, INTF_VSYNC_PERIOD_F0, vsync_period * hsync_period);
 	DPU_REG_WRITE(c, INTF_VSYNC_PULSE_WIDTH_F0,
@@ -211,6 +231,11 @@ static void dpu_hw_intf_setup_timing_engine(struct dpu_hw_intf *ctx,
 	DPU_REG_WRITE(c, INTF_FRAME_LINE_COUNT_EN, 0x3);
 	DPU_REG_WRITE(c, INTF_CONFIG, intf_cfg);
 	DPU_REG_WRITE(c, INTF_PANEL_FORMAT, panel_format);
+	if (ctx->cap->features & BIT(DPU_DATA_HCTL_EN)) {
+		DPU_REG_WRITE(c, INTF_CONFIG2, intf_cfg2);
+		DPU_REG_WRITE(c, INTF_DISPLAY_DATA_HCTL, display_data_hctl);
+		DPU_REG_WRITE(c, INTF_ACTIVE_DATA_HCTL, active_data_hctl);
+	}
 }
 
 static void dpu_hw_intf_enable_timing_engine(

drivers/gpu/drm/msm/disp/dpu1/dpu_hw_intf.h

@@ -30,6 +30,8 @@ struct intf_timing_params {
 	u32 border_clr;
 	u32 underflow_clr;
 	u32 hsync_skew;
+
+	bool wide_bus_en;
 };
 
 struct intf_prog_fetch {