[v6 02/13] drm: Parse HDR metadata info from EDID

[Uma Shankar]

HDR metadata block is introduced in CEA-861.3 spec.
Parsing the same to get the panel's HDR metadata.

v2: Rebase and added Ville's POC changes to the patch.

v3: No Change

v4: Addressed Shashank's review comments

Signed-off-by: Uma Shankar <uma.shankar at intel.com>
---
 drivers/gpu/drm/drm_edid.c | 49 ++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 49 insertions(+)

diff --git a/drivers/gpu/drm/drm_edid.c b/drivers/gpu/drm/drm_edid.c
index fa39592..fd8a621a 100644
--- a/drivers/gpu/drm/drm_edid.c
+++ b/drivers/gpu/drm/drm_edid.c
@@ -2840,6 +2840,7 @@ static int drm_cvt_modes(struct drm_connector *connector,
 #define VIDEO_BLOCK     0x02
 #define VENDOR_BLOCK    0x03
 #define SPEAKER_BLOCK	0x04
+#define HDR_STATIC_METADATA_BLOCK	0x6
 #define USE_EXTENDED_TAG 0x07
 #define EXT_VIDEO_CAPABILITY_BLOCK 0x00
 #define EXT_VIDEO_DATA_BLOCK_420	0x0E
@@ -3587,6 +3588,12 @@ static int add_3d_struct_modes(struct drm_connector *connector, u16 structure,
 }
 
 static int
+cea_db_payload_len_ext(const u8 *db)
+{
+	return (db[0] & 0x1f) - 1;
+}
+
+static int
 cea_db_extended_tag(const u8 *db)
 {
 	return db[1];
@@ -3822,6 +3829,46 @@ static void fixup_detailed_cea_mode_clock(struct drm_display_mode *mode)
 	mode->clock = clock;
 }
 
+static bool cea_db_is_hdmi_hdr_metadata_block(const u8 *db)
+{
+	if (cea_db_tag(db) != USE_EXTENDED_TAG)
+		return false;
+
+	if (db[1] != HDR_STATIC_METADATA_BLOCK)
+		return false;
+
+	return true;
+}
+
+static uint8_t eotf_supported(const u8 *edid_ext)
+{
+	return edid_ext[2] &
+		(BIT(HDMI_EOTF_TRADITIONAL_GAMMA_SDR) |
+		 BIT(HDMI_EOTF_TRADITIONAL_GAMMA_HDR) |
+		 BIT(HDMI_EOTF_SMPTE_ST2084));
+}
+
+static uint8_t hdr_metadata_type(const u8 *edid_ext)
+{
+	return edid_ext[3] &
+		BIT(HDMI_STATIC_METADATA_TYPE1);
+}
+
+static void
+drm_parse_hdr_metadata_block(struct drm_connector *connector, const u8 *db)
+{
+	u16 len;
+
+	len = cea_db_payload_len_ext(db);
+	connector->hdr_metadata.eotf = eotf_supported(db);
+	connector->hdr_metadata.metadata_type = hdr_metadata_type(db);
+
+	if (len >= 5)
+		connector->hdr_metadata.max_fall = db[5];
+	if (len >= 4)
+		connector->hdr_metadata.max_cll = db[4];
+}
+
 static void
 drm_parse_hdmi_vsdb_audio(struct drm_connector *connector, const u8 *db)
 {
@@ -4449,6 +4496,8 @@ static void drm_parse_cea_ext(struct drm_connector *connector,
 			drm_parse_y420cmdb_bitmap(connector, db);
 		if (cea_db_is_vcdb(db))
 			drm_parse_vcdb(connector, db);
+		if (cea_db_is_hdmi_hdr_metadata_block(db))
+			drm_parse_hdr_metadata_block(connector, db);
 	}
 }
 
-- 
1.9.1