drm/edid: Parse DSC1.2 cap fields from HFVSDB block

This patch parses HFVSDB fields for DSC1.2 capabilities of an
HDMI2.1 sink. These fields are required by a source to understand the
DSC capability of the sink, to set appropriate PPS parameters,
before transmitting compressed data stream.

v2: Addressed following issues as suggested by Uma Shankar:
-Added a new struct for hdmi dsc cap
-Fixed bugs in macros usage.
Signed-off-by: Ankit Nautiyal <ankit.k.nautiyal@intel.com>
Reviewed-by: Uma Shankar <uma.shankar@intel.com>
[Jani: Fixed checkpatch PARENTHESIS_ALIGNMENT.]
Signed-off-by: Jani Nikula <jani.nikula@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20201218103723.30844-4-ankit.k.nautiyal@intel.com

drivers/gpu/drm/drm_edid.c

@@ -4939,11 +4939,70 @@ static void drm_parse_hdmi_forum_vsdb(struct drm_connector *connector,
 
 	if (hf_vsdb[7]) {
 		u8 max_frl_rate;
+		u8 dsc_max_frl_rate;
+		u8 dsc_max_slices;
+		struct drm_hdmi_dsc_cap *hdmi_dsc = &hdmi->dsc_cap;
 
 		DRM_DEBUG_KMS("hdmi_21 sink detected. parsing edid\n");
 		max_frl_rate = (hf_vsdb[7] & DRM_EDID_MAX_FRL_RATE_MASK) >> 4;
 		drm_get_max_frl_rate(max_frl_rate, &hdmi->max_lanes,
 				     &hdmi->max_frl_rate_per_lane);
+		hdmi_dsc->v_1p2 = hf_vsdb[11] & DRM_EDID_DSC_1P2;
+
+		if (hdmi_dsc->v_1p2) {
+			hdmi_dsc->native_420 = hf_vsdb[11] & DRM_EDID_DSC_NATIVE_420;
+			hdmi_dsc->all_bpp = hf_vsdb[11] & DRM_EDID_DSC_ALL_BPP;
+
+			if (hf_vsdb[11] & DRM_EDID_DSC_16BPC)
+				hdmi_dsc->bpc_supported = 16;
+			else if (hf_vsdb[11] & DRM_EDID_DSC_12BPC)
+				hdmi_dsc->bpc_supported = 12;
+			else if (hf_vsdb[11] & DRM_EDID_DSC_10BPC)
+				hdmi_dsc->bpc_supported = 10;
+			else
+				hdmi_dsc->bpc_supported = 0;
+
+			dsc_max_frl_rate = (hf_vsdb[12] & DRM_EDID_DSC_MAX_FRL_RATE_MASK) >> 4;
+			drm_get_max_frl_rate(dsc_max_frl_rate, &hdmi_dsc->max_lanes,
+					     &hdmi_dsc->max_frl_rate_per_lane);
+			hdmi_dsc->total_chunk_kbytes = hf_vsdb[13] & DRM_EDID_DSC_TOTAL_CHUNK_KBYTES;
+
+			dsc_max_slices = hf_vsdb[12] & DRM_EDID_DSC_MAX_SLICES;
+			switch (dsc_max_slices) {
+			case 1:
+				hdmi_dsc->max_slices = 1;
+				hdmi_dsc->clk_per_slice = 340;
+				break;
+			case 2:
+				hdmi_dsc->max_slices = 2;
+				hdmi_dsc->clk_per_slice = 340;
+				break;
+			case 3:
+				hdmi_dsc->max_slices = 4;
+				hdmi_dsc->clk_per_slice = 340;
+				break;
+			case 4:
+				hdmi_dsc->max_slices = 8;
+				hdmi_dsc->clk_per_slice = 340;
+				break;
+			case 5:
+				hdmi_dsc->max_slices = 8;
+				hdmi_dsc->clk_per_slice = 400;
+				break;
+			case 6:
+				hdmi_dsc->max_slices = 12;
+				hdmi_dsc->clk_per_slice = 400;
+				break;
+			case 7:
+				hdmi_dsc->max_slices = 16;
+				hdmi_dsc->clk_per_slice = 400;
+				break;
+			case 0:
+			default:
+				hdmi_dsc->max_slices = 0;
+				hdmi_dsc->clk_per_slice = 0;
+			}
+		}
 	}
 
 	drm_parse_ycbcr420_deep_color_info(connector, hf_vsdb);

include/drm/drm_connector.h

@@ -175,6 +175,46 @@ struct drm_scdc {
 	struct drm_scrambling scrambling;
 };
 
+/**
+ * struct drm_hdmi_dsc_cap - DSC capabilities of HDMI sink
+ *
+ * Describes the DSC support provided by HDMI 2.1 sink.
+ * The information is fetched fom additional HFVSDB blocks defined
+ * for HDMI 2.1.
+ */
+struct drm_hdmi_dsc_cap {
+	/** @v_1p2: flag for dsc1.2 version support by sink */
+	bool v_1p2;
+
+	/** @native_420: Does sink support DSC with 4:2:0 compression */
+	bool native_420;
+
+	/**
+	 * @all_bpp: Does sink support all bpp with 4:4:4: or 4:2:2
+	 * compressed formats
+	 */
+	bool all_bpp;
+
+	/**
+	 * @bpc_supported: compressed bpc supported by sink : 10, 12 or 16 bpc
+	 */
+	u8 bpc_supported;
+
+	/** @max_slices: maximum number of Horizontal slices supported by */
+	u8 max_slices;
+
+	/** @clk_per_slice : max pixel clock in MHz supported per slice */
+	int clk_per_slice;
+
+	/** @max_lanes : dsc max lanes supported for Fixed rate Link training */
+	u8 max_lanes;
+
+	/** @max_frl_rate_per_lane : maximum frl rate with DSC per lane */
+	u8 max_frl_rate_per_lane;
+
+	/** @total_chunk_kbytes: max size of chunks in KBs supported per line*/
+	u8 total_chunk_kbytes;
+};
 
 /**
  * struct drm_hdmi_info - runtime information about the connected HDMI sink
@@ -213,6 +253,9 @@ struct drm_hdmi_info {
 
 	/** @max_lanes: supported by sink */
 	u8 max_lanes;
+
+	/** @dsc_cap: DSC capabilities of the sink */
+	struct drm_hdmi_dsc_cap dsc_cap;
 };
 
 /**