cta: add support for Room Configuration data blocks

Signed-off-by: Sebastian Wick <sebastian.wick@redhat.com>

cta.c

@@ -1226,6 +1226,81 @@ parse_infoframe_block(struct di_edid_cta *cta,
 	return true;
 }
 
+static double
+decode_coord(unsigned char x)
+{
+	signed char s = (signed char)x;
+
+	return s / 64.0;
+}
+
+static bool
+parse_room_config_block(struct di_edid_cta *cta,
+			struct di_cta_room_configuration *rc,
+			const uint8_t *data, size_t size)
+{
+	bool has_display_coords;
+	bool has_speaker_count;
+
+	if (size < 4) {
+		add_failure(cta, "Room Configuration Data Block: Empty Data Block with length %u.",
+			    size);
+		return false;
+	}
+
+	has_display_coords = has_bit(data[0], 7);
+	has_speaker_count = has_bit(data[0], 6);
+	rc->has_speaker_location_descriptors = has_bit(data[0], 5);
+
+	if (has_speaker_count) {
+		rc->speaker_count = get_bit_range(data[0], 4, 0) + 1;
+	} else {
+		if (get_bit_range(data[0], 4, 0) != 0) {
+			add_failure(cta, "Room Configuration Data Block: "
+					 "'Speaker' flag is 0, but the Speaker Count is not 0.");
+		}
+
+		if (rc->has_speaker_location_descriptors) {
+			add_failure(cta, "Room Configuration Data Block: "
+					 "'Speaker' flag is 0, but there are "
+					 "Speaker Location Descriptors.");
+		}
+	}
+
+	parse_speaker_alloc(cta, &rc->speakers, &data[1], "Room Configuration Data Block");
+
+	rc->max_x = 16;
+	rc->max_y = 16;
+	rc->max_z = 8;
+	rc->display_x = 0.0;
+	rc->display_y = 1.0;
+	rc->display_z = 0.0;
+
+	if (size < 7) {
+		if (has_display_coords)
+			add_failure(cta, "Room Configuration Data Block: "
+					 "'Display' flag is 1, but the Display and Maximum coordinates are not present.");
+		return true;
+	}
+
+	rc->max_x = data[4];
+	rc->max_y = data[5];
+	rc->max_z = data[6];
+
+	if (size < 10) {
+		if (has_display_coords)
+			add_failure(cta, "Room Configuration Data Block: "
+					 "'Display' flag is 1, but the Display coordinates are not present.");
+		return true;
+	}
+
+	rc->display_x = decode_coord(data[7]);
+	rc->display_y = decode_coord(data[8]);
+	rc->display_z = decode_coord(data[9]);
+
+	return true;
+}
+
 static void
 destroy_data_block(struct di_cta_data_block *data_block)
 {
@@ -1373,6 +1448,10 @@ parse_data_block(struct di_edid_cta *cta, uint8_t raw_tag, const uint8_t *data,
 			break;
 		case 19:
 			tag = DI_CTA_DATA_BLOCK_ROOM_CONFIG;
+			if (!parse_room_config_block(cta,
+						     &data_block->room_config,
+						     data, size))
+				goto skip;
 			break;
 		case 20:
 			tag = DI_CTA_DATA_BLOCK_SPEAKER_LOCATION;
@@ -1688,3 +1767,12 @@ di_cta_data_block_get_vesa_transfer_characteristics(const struct di_cta_data_blo
 	}
 	return &block->vesa_transfer_characteristics;
 }
+
+const struct di_cta_room_configuration *
+di_cta_data_block_get_room_configuration(const struct di_cta_data_block *block)
+{
+	if (block->tag != DI_CTA_DATA_BLOCK_ROOM_CONFIG) {
+		return NULL;
+	}
+	return &block->room_config;
+}

include/cta.h

@@ -155,6 +155,8 @@ struct di_cta_data_block {
 	struct di_cta_ycbcr420_cap_map ycbcr420_cap_map;
 	/* Used for DI_CTA_DATA_BLOCK_INFOFRAME */
 	struct di_cta_infoframe_block_priv infoframe;
+	/* Used for DI_CTA_DATA_BLOCK_ROOM_CONFIG */
+	struct di_cta_room_configuration room_config;
 };
 
 extern const struct di_cta_video_format _di_cta_video_formats[];

include/libdisplay-info/cta.h

@@ -930,6 +930,38 @@ struct di_cta_infoframe_block {
 const struct di_cta_infoframe_block *
 di_cta_data_block_get_infoframe(const struct di_cta_data_block *block);
 
+/**
+ * Room Configuration Data Block, defined in section 7.5.15.
+ */
+struct di_cta_room_configuration {
+	/* Present speakers */
+	struct di_cta_speaker_allocation speakers;
+	/* Total number of L-PCM channels */
+	int speaker_count;
+	/* All speakers are defined by Speaker Location Descriptors */
+	bool has_speaker_location_descriptors;
+	/* Rectangular box that contains all of the components of interest
+	 * centered on the Primary Listening Position.
+	 * See 7.5.16.1 Room Coordinate System
+	 * Only valid if any Speaker Location Descriptor has coordinates set. */
+	int max_x; /* in dm */
+	int max_y; /* in dm */
+	int max_z; /* in dm */
+	/* The position of the center of the display in normalized coordinates.
+	 * Only valid if any Speaker Location Descriptor has coordinates set. */
+	double display_x; /* normalized to max_x */
+	double display_y; /* normalized to max_y */
+	double display_z; /* normalized to max_z */
+};
+
+/**
+ * Get the Room Configuration from a CTA data block.
+ *
+ * Returns NULL if the data block tag is not DI_CTA_DATA_BLOCK_ROOM_CONFIG.
+ */
+const struct di_cta_room_configuration *
+di_cta_data_block_get_room_configuration(const struct di_cta_data_block *block);
+
 /**
  * Get a list of EDID detailed timing definitions.
  *