drm/bridge: synopsys: dw-hdmi: add bus format negociation

Add the atomic_get_output_bus_fmts, atomic_get_input_bus_fmts to negociate
the possible output and input formats for the current mode and monitor,
and use the negotiated formats in a basic atomic_check callback.
Signed-off-by: Neil Armstrong <narmstrong@baylibre.com>
Reviewed-by: Boris Brezillon <boris.brezillon@collabora.com>
Reviewed-by: Jernej Škrabec <jernej.skrabec@siol.net>
Link: https://patchwork.freedesktop.org/patch/msgid/20200304104052.17196-5-narmstrong@baylibre.com

drivers/gpu/drm/bridge/synopsys/dw-hdmi.c

@@ -2097,11 +2097,10 @@ static int dw_hdmi_setup(struct dw_hdmi *hdmi, struct drm_display_mode *mode)
 	hdmi->hdmi_data.video_mode.mpixelrepetitionoutput = 0;
 	hdmi->hdmi_data.video_mode.mpixelrepetitioninput = 0;
 
-	/* TOFIX: Get input format from plat data or fallback to RGB888 */
 	if (hdmi->plat_data->input_bus_format)
 		hdmi->hdmi_data.enc_in_bus_format =
 			hdmi->plat_data->input_bus_format;
-	else
+	else if (hdmi->hdmi_data.enc_in_bus_format == MEDIA_BUS_FMT_FIXED)
 		hdmi->hdmi_data.enc_in_bus_format = MEDIA_BUS_FMT_RGB888_1X24;
 
 	/* TOFIX: Get input encoding from plat data or fallback to none */
@@ -2111,8 +2110,8 @@ static int dw_hdmi_setup(struct dw_hdmi *hdmi, struct drm_display_mode *mode)
 	else
 		hdmi->hdmi_data.enc_in_encoding = V4L2_YCBCR_ENC_DEFAULT;
 
-	/* TOFIX: Default to RGB888 output format */
-	hdmi->hdmi_data.enc_out_bus_format = MEDIA_BUS_FMT_RGB888_1X24;
+	if (hdmi->hdmi_data.enc_out_bus_format == MEDIA_BUS_FMT_FIXED)
+		hdmi->hdmi_data.enc_out_bus_format = MEDIA_BUS_FMT_RGB888_1X24;
 
 	hdmi->hdmi_data.pix_repet_factor = 0;
 	hdmi->hdmi_data.hdcp_enable = 0;
@@ -2390,6 +2389,277 @@ static const struct drm_connector_helper_funcs dw_hdmi_connector_helper_funcs =
 	.atomic_check = dw_hdmi_connector_atomic_check,
 };
 
+/*
+ * Possible output formats :
+ * - MEDIA_BUS_FMT_UYYVYY16_0_5X48,
+ * - MEDIA_BUS_FMT_UYYVYY12_0_5X36,
+ * - MEDIA_BUS_FMT_UYYVYY10_0_5X30,
+ * - MEDIA_BUS_FMT_UYYVYY8_0_5X24,
+ * - MEDIA_BUS_FMT_YUV16_1X48,
+ * - MEDIA_BUS_FMT_RGB161616_1X48,
+ * - MEDIA_BUS_FMT_UYVY12_1X24,
+ * - MEDIA_BUS_FMT_YUV12_1X36,
+ * - MEDIA_BUS_FMT_RGB121212_1X36,
+ * - MEDIA_BUS_FMT_UYVY10_1X20,
+ * - MEDIA_BUS_FMT_YUV10_1X30,
+ * - MEDIA_BUS_FMT_RGB101010_1X30,
+ * - MEDIA_BUS_FMT_UYVY8_1X16,
+ * - MEDIA_BUS_FMT_YUV8_1X24,
+ * - MEDIA_BUS_FMT_RGB888_1X24,
+ */
+
+/* Can return a maximum of 11 possible output formats for a mode/connector */
+#define MAX_OUTPUT_SEL_FORMATS	11
+
+static u32 *dw_hdmi_bridge_atomic_get_output_bus_fmts(struct drm_bridge *bridge,
+					struct drm_bridge_state *bridge_state,
+					struct drm_crtc_state *crtc_state,
+					struct drm_connector_state *conn_state,
+					unsigned int *num_output_fmts)
+{
+	struct drm_connector *conn = conn_state->connector;
+	struct drm_display_info *info = &conn->display_info;
+	struct drm_display_mode *mode = &crtc_state->mode;
+	u8 max_bpc = conn_state->max_requested_bpc;
+	bool is_hdmi2_sink = info->hdmi.scdc.supported ||
+			     (info->color_formats & DRM_COLOR_FORMAT_YCRCB420);
+	u32 *output_fmts;
+	unsigned int i = 0;
+
+	*num_output_fmts = 0;
+
+	output_fmts = kcalloc(MAX_OUTPUT_SEL_FORMATS, sizeof(*output_fmts),
+			      GFP_KERNEL);
+	if (!output_fmts)
+		return NULL;
+
+	/* If dw-hdmi is the only bridge, avoid negociating with ourselves */
+	if (list_is_singular(&bridge->encoder->bridge_chain)) {
+		*num_output_fmts = 1;
+		output_fmts[0] = MEDIA_BUS_FMT_FIXED;
+
+		return output_fmts;
+	}
+
+	/*
+	 * If the current mode enforces 4:2:0, force the output but format
+	 * to 4:2:0 and do not add the YUV422/444/RGB formats
+	 */
+	if (conn->ycbcr_420_allowed &&
+	    (drm_mode_is_420_only(info, mode) ||
+	     (is_hdmi2_sink && drm_mode_is_420_also(info, mode)))) {
+
+		/* Order bus formats from 16bit to 8bit if supported */
+		if (max_bpc >= 16 && info->bpc == 16 &&
+		    (info->hdmi.y420_dc_modes & DRM_EDID_YCBCR420_DC_48))
+			output_fmts[i++] = MEDIA_BUS_FMT_UYYVYY16_0_5X48;
+
+		if (max_bpc >= 12 && info->bpc >= 12 &&
+		    (info->hdmi.y420_dc_modes & DRM_EDID_YCBCR420_DC_36))
+			output_fmts[i++] = MEDIA_BUS_FMT_UYYVYY12_0_5X36;
+
+		if (max_bpc >= 10 && info->bpc >= 10 &&
+		    (info->hdmi.y420_dc_modes & DRM_EDID_YCBCR420_DC_30))
+			output_fmts[i++] = MEDIA_BUS_FMT_UYYVYY10_0_5X30;
+
+		/* Default 8bit fallback */
+		output_fmts[i++] = MEDIA_BUS_FMT_UYYVYY8_0_5X24;
+
+		*num_output_fmts = i;
+
+		return output_fmts;
+	}
+
+	/*
+	 * Order bus formats from 16bit to 8bit and from YUV422 to RGB
+	 * if supported. In any case the default RGB888 format is added
+	 */
+
+	if (max_bpc >= 16 && info->bpc == 16) {
+		if (info->color_formats & DRM_COLOR_FORMAT_YCRCB444)
+			output_fmts[i++] = MEDIA_BUS_FMT_YUV16_1X48;
+
+		output_fmts[i++] = MEDIA_BUS_FMT_RGB161616_1X48;
+	}
+
+	if (max_bpc >= 12 && info->bpc >= 12) {
+		if (info->color_formats & DRM_COLOR_FORMAT_YCRCB422)
+			output_fmts[i++] = MEDIA_BUS_FMT_UYVY12_1X24;
+
+		if (info->color_formats & DRM_COLOR_FORMAT_YCRCB444)
+			output_fmts[i++] = MEDIA_BUS_FMT_YUV12_1X36;
+
+		output_fmts[i++] = MEDIA_BUS_FMT_RGB121212_1X36;
+	}
+
+	if (max_bpc >= 10 && info->bpc >= 10) {
+		if (info->color_formats & DRM_COLOR_FORMAT_YCRCB422)
+			output_fmts[i++] = MEDIA_BUS_FMT_UYVY10_1X20;
+
+		if (info->color_formats & DRM_COLOR_FORMAT_YCRCB444)
+			output_fmts[i++] = MEDIA_BUS_FMT_YUV10_1X30;
+
+		output_fmts[i++] = MEDIA_BUS_FMT_RGB101010_1X30;
+	}
+
+	if (info->color_formats & DRM_COLOR_FORMAT_YCRCB422)
+		output_fmts[i++] = MEDIA_BUS_FMT_UYVY8_1X16;
+
+	if (info->color_formats & DRM_COLOR_FORMAT_YCRCB444)
+		output_fmts[i++] = MEDIA_BUS_FMT_YUV8_1X24;
+
+	/* Default 8bit RGB fallback */
+	output_fmts[i++] = MEDIA_BUS_FMT_RGB888_1X24;
+
+	*num_output_fmts = i;
+
+	return output_fmts;
+}
+
+/*
+ * Possible input formats :
+ * - MEDIA_BUS_FMT_RGB888_1X24
+ * - MEDIA_BUS_FMT_YUV8_1X24
+ * - MEDIA_BUS_FMT_UYVY8_1X16
+ * - MEDIA_BUS_FMT_UYYVYY8_0_5X24
+ * - MEDIA_BUS_FMT_RGB101010_1X30
+ * - MEDIA_BUS_FMT_YUV10_1X30
+ * - MEDIA_BUS_FMT_UYVY10_1X20
+ * - MEDIA_BUS_FMT_UYYVYY10_0_5X30
+ * - MEDIA_BUS_FMT_RGB121212_1X36
+ * - MEDIA_BUS_FMT_YUV12_1X36
+ * - MEDIA_BUS_FMT_UYVY12_1X24
+ * - MEDIA_BUS_FMT_UYYVYY12_0_5X36
+ * - MEDIA_BUS_FMT_RGB161616_1X48
+ * - MEDIA_BUS_FMT_YUV16_1X48
+ * - MEDIA_BUS_FMT_UYYVYY16_0_5X48
+ */
+
+/* Can return a maximum of 3 possible input formats for an output format */
+#define MAX_INPUT_SEL_FORMATS	3
+
+static u32 *dw_hdmi_bridge_atomic_get_input_bus_fmts(struct drm_bridge *bridge,
+					struct drm_bridge_state *bridge_state,
+					struct drm_crtc_state *crtc_state,
+					struct drm_connector_state *conn_state,
+					u32 output_fmt,
+					unsigned int *num_input_fmts)
+{
+	u32 *input_fmts;
+	unsigned int i = 0;
+
+	*num_input_fmts = 0;
+
+	input_fmts = kcalloc(MAX_INPUT_SEL_FORMATS, sizeof(*input_fmts),
+			     GFP_KERNEL);
+	if (!input_fmts)
+		return NULL;
+
+	switch (output_fmt) {
+	/* If MEDIA_BUS_FMT_FIXED is tested, return default bus format */
+	case MEDIA_BUS_FMT_FIXED:
+		input_fmts[i++] = MEDIA_BUS_FMT_RGB888_1X24;
+		break;
+	/* 8bit */
+	case MEDIA_BUS_FMT_RGB888_1X24:
+		input_fmts[i++] = MEDIA_BUS_FMT_RGB888_1X24;
+		input_fmts[i++] = MEDIA_BUS_FMT_YUV8_1X24;
+		input_fmts[i++] = MEDIA_BUS_FMT_UYVY8_1X16;
+		break;
+	case MEDIA_BUS_FMT_YUV8_1X24:
+		input_fmts[i++] = MEDIA_BUS_FMT_YUV8_1X24;
+		input_fmts[i++] = MEDIA_BUS_FMT_UYVY8_1X16;
+		input_fmts[i++] = MEDIA_BUS_FMT_RGB888_1X24;
+		break;
+	case MEDIA_BUS_FMT_UYVY8_1X16:
+		input_fmts[i++] = MEDIA_BUS_FMT_UYVY8_1X16;
+		input_fmts[i++] = MEDIA_BUS_FMT_YUV8_1X24;
+		input_fmts[i++] = MEDIA_BUS_FMT_RGB888_1X24;
+		break;
+
+	/* 10bit */
+	case MEDIA_BUS_FMT_RGB101010_1X30:
+		input_fmts[i++] = MEDIA_BUS_FMT_RGB101010_1X30;
+		input_fmts[i++] = MEDIA_BUS_FMT_YUV10_1X30;
+		input_fmts[i++] = MEDIA_BUS_FMT_UYVY10_1X20;
+		break;
+	case MEDIA_BUS_FMT_YUV10_1X30:
+		input_fmts[i++] = MEDIA_BUS_FMT_YUV10_1X30;
+		input_fmts[i++] = MEDIA_BUS_FMT_UYVY10_1X20;
+		input_fmts[i++] = MEDIA_BUS_FMT_RGB101010_1X30;
+		break;
+	case MEDIA_BUS_FMT_UYVY10_1X20:
+		input_fmts[i++] = MEDIA_BUS_FMT_UYVY10_1X20;
+		input_fmts[i++] = MEDIA_BUS_FMT_YUV10_1X30;
+		input_fmts[i++] = MEDIA_BUS_FMT_RGB101010_1X30;
+		break;
+
+	/* 12bit */
+	case MEDIA_BUS_FMT_RGB121212_1X36:
+		input_fmts[i++] = MEDIA_BUS_FMT_RGB121212_1X36;
+		input_fmts[i++] = MEDIA_BUS_FMT_YUV12_1X36;
+		input_fmts[i++] = MEDIA_BUS_FMT_UYVY12_1X24;
+		break;
+	case MEDIA_BUS_FMT_YUV12_1X36:
+		input_fmts[i++] = MEDIA_BUS_FMT_YUV12_1X36;
+		input_fmts[i++] = MEDIA_BUS_FMT_UYVY12_1X24;
+		input_fmts[i++] = MEDIA_BUS_FMT_RGB121212_1X36;
+		break;
+	case MEDIA_BUS_FMT_UYVY12_1X24:
+		input_fmts[i++] = MEDIA_BUS_FMT_UYVY12_1X24;
+		input_fmts[i++] = MEDIA_BUS_FMT_YUV12_1X36;
+		input_fmts[i++] = MEDIA_BUS_FMT_RGB121212_1X36;
+		break;
+
+	/* 16bit */
+	case MEDIA_BUS_FMT_RGB161616_1X48:
+		input_fmts[i++] = MEDIA_BUS_FMT_RGB161616_1X48;
+		input_fmts[i++] = MEDIA_BUS_FMT_YUV16_1X48;
+		break;
+	case MEDIA_BUS_FMT_YUV16_1X48:
+		input_fmts[i++] = MEDIA_BUS_FMT_YUV16_1X48;
+		input_fmts[i++] = MEDIA_BUS_FMT_RGB161616_1X48;
+		break;
+
+	/*YUV 4:2:0 */
+	case MEDIA_BUS_FMT_UYYVYY8_0_5X24:
+	case MEDIA_BUS_FMT_UYYVYY10_0_5X30:
+	case MEDIA_BUS_FMT_UYYVYY12_0_5X36:
+	case MEDIA_BUS_FMT_UYYVYY16_0_5X48:
+		input_fmts[i++] = output_fmt;
+		break;
+	}
+
+	*num_input_fmts = i;
+
+	if (*num_input_fmts == 0) {
+		kfree(input_fmts);
+		input_fmts = NULL;
+	}
+
+	return input_fmts;
+}
+
+static int dw_hdmi_bridge_atomic_check(struct drm_bridge *bridge,
+				       struct drm_bridge_state *bridge_state,
+				       struct drm_crtc_state *crtc_state,
+				       struct drm_connector_state *conn_state)
+{
+	struct dw_hdmi *hdmi = bridge->driver_private;
+
+	hdmi->hdmi_data.enc_out_bus_format =
+			bridge_state->output_bus_cfg.format;
+
+	hdmi->hdmi_data.enc_in_bus_format =
+			bridge_state->input_bus_cfg.format;
+
+	dev_dbg(hdmi->dev, "input format 0x%04x, output format 0x%04x\n",
+		bridge_state->input_bus_cfg.format,
+		bridge_state->output_bus_cfg.format);
+
+	return 0;
+}
+
 static int dw_hdmi_bridge_attach(struct drm_bridge *bridge,
 				 enum drm_bridge_attach_flags flags)
 {
@@ -2511,6 +2781,9 @@ static const struct drm_bridge_funcs dw_hdmi_bridge_funcs = {
 	.atomic_reset = drm_atomic_helper_bridge_reset,
 	.attach = dw_hdmi_bridge_attach,
 	.detach = dw_hdmi_bridge_detach,
+	.atomic_check = dw_hdmi_bridge_atomic_check,
+	.atomic_get_output_bus_fmts = dw_hdmi_bridge_atomic_get_output_bus_fmts,
+	.atomic_get_input_bus_fmts = dw_hdmi_bridge_atomic_get_input_bus_fmts,
 	.enable = dw_hdmi_bridge_enable,
 	.disable = dw_hdmi_bridge_disable,
 	.mode_set = dw_hdmi_bridge_mode_set,