Bluetooth: AVRCP: implementation for subunit info command.

This patch alllows to acquire the subunit info from the remote device.

Signed-off-by: Zihao Gao <[email protected]>

Author: gzh-terry

include/zephyr/bluetooth/classic/avrcp.h

@@ -24,6 +24,13 @@ struct bt_avrcp_unit_info_rsp {
 	uint32_t company_id;
 };
 
+struct bt_avrcp_subunit_info_rsp {
+	uint8_t subunit_type;
+	uint8_t max_subunit_id;
+	const uint8_t *extended_subunit_type; /**< contains max_subunit_id items */
+	const uint8_t *extended_subunit_id; /**< contains max_subunit_id items */
+};
+
 struct bt_avrcp_cb {
 	/** @brief An AVRCP connection has been established.
 	 *
@@ -41,14 +48,22 @@ struct bt_avrcp_cb {
 	 *  @param avrcp AVRCP connection object.
 	 */
 	void (*disconnected)(struct bt_avrcp *avrcp);
-	/** @brief Callback function for bt_avrcp_get_unit_info()
+	/** @brief Callback function for bt_avrcp_get_unit_info().
 	 *
 	 *  Called when the get unit info process is completed.
 	 *
 	 *  @param avrcp AVRCP connection object.
 	 *  @param rsp The response for UNIT INFO command.
 	 */
 	void (*unit_info_rsp)(struct bt_avrcp *avrcp, struct bt_avrcp_unit_info_rsp *rsp);
+	/** @brief Callback function for bt_avrcp_get_subunit_info().
+	 *
+	 *  Called when the get subunit info process is completed.
+	 *
+	 *  @param avrcp AVRCP connection object.
+	 *  @param rsp The response for SUBUNIT INFO command.
+	 */
+	void (*subunit_info_rsp)(struct bt_avrcp *avrcp, struct bt_avrcp_subunit_info_rsp *rsp);
 };
 
 /** @brief Connect AVRCP.
@@ -86,14 +101,25 @@ int bt_avrcp_register_cb(const struct bt_avrcp_cb *cb);
 
 /** @brief Get AVRCP Unit Info.
  *
- *  This function obtains information that pertains to the unit as a whole.
+ *  This function obtains information that pertains to the AV/C unit as a whole.
  *
  *  @param avrcp The AVRCP instance.
  *
  *  @return 0 in case of success or error code in case of error.
  */
 int bt_avrcp_get_unit_info(struct bt_avrcp *avrcp);
 
+/** @brief Get AVRCP Subunit Info.
+ *
+ *  This function obtains information about the subunit(s) of an AV/C unit. A device with AVRCP
+ *  may support other subunits than the panel subunit if other profiles co-exist in the device.
+ *
+ *  @param avrcp The AVRCP instance.
+ *
+ *  @return 0 in case of success or error code in case of error.
+ */
+int bt_avrcp_get_subunit_info(struct bt_avrcp *avrcp);
+
 #ifdef __cplusplus
 }
 #endif

subsys/bluetooth/host/classic/avrcp.c

@@ -260,7 +260,7 @@ static void avrcp_unit_info_handler(struct bt_avrcp *avrcp, struct net_buf *buf,
 		if ((avrcp_cb != NULL) && (avrcp_cb->unit_info_rsp != NULL)) {
 			net_buf_pull(buf, sizeof(*avrcp_hdr));
 			net_buf_pull_u8(buf); /* Always 0x07 */
-			rsp.unit_type = (net_buf_pull_u8(buf) >> 3); /* Bit [8:4] Shall be 0x09 */
+			rsp.unit_type = FIELD_GET(GENMASK(7, 3), net_buf_pull_u8(buf));
 			rsp.company_id = net_buf_pull_be24(buf);
 			avrcp_cb->unit_info_rsp(avrcp, &rsp);
 		}
@@ -270,7 +270,28 @@ static void avrcp_unit_info_handler(struct bt_avrcp *avrcp, struct net_buf *buf,
 static void avrcp_subunit_info_handler(struct bt_avrcp *avrcp, struct net_buf *buf,
 					   bt_avctp_cr_t cr)
 {
-	/* ToDo */
+	struct bt_avrcp_header *avrcp_hdr;
+	struct bt_avrcp_subunit_info_rsp rsp;
+	uint8_t tmp;
+
+	if (cr == BT_AVCTP_CMD) {
+		/* ToDo */
+	} else { /* BT_AVCTP_RESPONSE */
+		if ((avrcp_cb != NULL) && (avrcp_cb->subunit_info_rsp != NULL)) {
+			net_buf_pull(buf, sizeof(*avrcp_hdr));
+			net_buf_pull_u8(buf); /* Always 0x07 */
+			tmp = net_buf_pull_u8(buf);
+			rsp.subunit_type = FIELD_GET(GENMASK(7, 3), tmp);
+			rsp.max_subunit_id = FIELD_GET(GENMASK(2, 0), tmp);
+			if (buf->len < (rsp.max_subunit_id << 1)) {
+				LOG_ERR("Invalid subunit info response");
+				return;
+			}
+			rsp.extended_subunit_type = buf->data;
+			rsp.extended_subunit_id = rsp.extended_subunit_type + rsp.max_subunit_id;
+			avrcp_cb->subunit_info_rsp(avrcp, &rsp);
+		}
+	}
 }
 
 static void avrcp_pass_through_handler(struct bt_avrcp *avrcp, struct net_buf *buf,
@@ -459,6 +480,27 @@ static struct net_buf *avrcp_create_unit_pdu(struct bt_avrcp *avrcp, bt_avctp_cr
 	return buf;
 }
 
+static struct net_buf *avrcp_create_subunit_pdu(struct bt_avrcp *avrcp, bt_avctp_cr_t cr)
+{
+	struct net_buf *buf;
+	struct bt_avrcp_unit_info_cmd *cmd;
+
+	buf = avrcp_create_pdu(avrcp, cr);
+	if (!buf) {
+		return buf;
+	}
+
+	cmd = net_buf_add(buf, sizeof(*cmd));
+	memset(cmd, 0, sizeof(*cmd));
+	BT_AVRCP_HDR_SET_CTYPE(&cmd->hdr, cr == BT_AVCTP_CMD ? BT_AVRCP_CTYPE_STATUS
+							     : BT_AVRCP_CTYPE_IMPLEMENTED_STABLE);
+	BT_AVRCP_HDR_SET_SUBUNIT_ID(&cmd->hdr, BT_AVRCP_SUBUNIT_ID_IGNORE);
+	BT_AVRCP_HDR_SET_SUBUNIT_TYPE(&cmd->hdr, BT_AVRCP_SUBUNIT_TYPE_UNIT);
+	cmd->hdr.opcode = BT_AVRCP_OPC_SUBUNIT_INFO;
+
+	return buf;
+}
+
 static int avrcp_send(struct bt_avrcp *avrcp, struct net_buf *buf)
 {
 	int err;
@@ -504,6 +546,24 @@ int bt_avrcp_get_unit_info(struct bt_avrcp *avrcp)
 	return avrcp_send(avrcp, buf);
 }
 
+int bt_avrcp_get_subunit_info(struct bt_avrcp *avrcp)
+{
+	struct net_buf *buf;
+	uint8_t param[5];
+
+	buf = avrcp_create_subunit_pdu(avrcp, BT_AVCTP_CMD);
+	if (!buf) {
+		return -ENOMEM;
+	}
+
+	memset(param, 0xFF, ARRAY_SIZE(param));
+	param[0] = FIELD_PREP(GENMASK(6, 4), AVRCP_SUBUNIT_PAGE) |
+		   FIELD_PREP(GENMASK(2, 0), AVRCP_SUBUNIT_EXTENSION_COED);
+	net_buf_add_mem(buf, param, sizeof(param));
+
+	return avrcp_send(avrcp, buf);
+}
+
 int bt_avrcp_register_cb(const struct bt_avrcp_cb *cb)
 {
 	avrcp_cb = cb;

subsys/bluetooth/host/classic/avrcp_internal.h

@@ -17,6 +17,9 @@
 #define AVRCP_CAT_3 BIT(2) /* Tuner */
 #define AVRCP_CAT_4 BIT(3) /* Menu */
 
+#define AVRCP_SUBUNIT_PAGE           (0) /* Fixed value according to AVRCP */
+#define AVRCP_SUBUNIT_EXTENSION_COED (7) /* Fixed value according to TA Document 2001012 */
+
 typedef enum __packed {
 	BT_AVRCP_CTYPE_CONTROL = 0x0,
 	BT_AVRCP_CTYPE_STATUS = 0x1,

subsys/bluetooth/host/classic/shell/avrcp.c

@@ -48,10 +48,24 @@ static void avrcp_unit_info_rsp(struct bt_avrcp *avrcp, struct bt_avrcp_unit_inf
 		    rsp->unit_type, rsp->company_id);
 }
 
+static void avrcp_subunit_info_rsp(struct bt_avrcp *avrcp, struct bt_avrcp_subunit_info_rsp *rsp)
+{
+	int i;
+
+	shell_print(ctx_shell,
+		    "AVRCP subunit info received, subunit type = 0x%02x, extended subunit = %d",
+		    rsp->subunit_type, rsp->max_subunit_id);
+	for (i = 0; i < rsp->max_subunit_id; i++) {
+		shell_print(ctx_shell, "extended subunit id = %d, subunit type = 0x%02x",
+			    rsp->extended_subunit_id[i], rsp->extended_subunit_type[i]);
+	}
+}
+
 static struct bt_avrcp_cb avrcp_cb = {
 	.connected = avrcp_connected,
 	.disconnected = avrcp_disconnected,
 	.unit_info_rsp = avrcp_unit_info_rsp,
+	.subunit_info_rsp = avrcp_subunit_info_rsp,
 };
 
 static int register_cb(const struct shell *sh)
@@ -141,12 +155,31 @@ static int cmd_get_unit_info(const struct shell *sh, int32_t argc, char *argv[])
 	return 0;
 }
 
+static int cmd_get_subunit_info(const struct shell *sh, int32_t argc, char *argv[])
+{
+	if (!avrcp_registered) {
+		if (register_cb(sh) != 0) {
+			return -ENOEXEC;
+		}
+	}
+
+	if (default_avrcp != NULL) {
+		bt_avrcp_get_subunit_info(default_avrcp);
+	} else {
+		shell_error(sh, "AVRCP is not connected");
+	}
+
+	return 0;
+}
+
 SHELL_STATIC_SUBCMD_SET_CREATE(avrcp_cmds,
 			       SHELL_CMD_ARG(register_cb, NULL, "register avrcp callbacks",
 					     cmd_register_cb, 1, 0),
 			       SHELL_CMD_ARG(connect, NULL, "<address>", cmd_connect, 2, 0),
 			       SHELL_CMD_ARG(disconnect, NULL, "<address>", cmd_disconnect, 2, 0),
 			       SHELL_CMD_ARG(get_unit, NULL, "<address>", cmd_get_unit_info, 2, 0),
+			       SHELL_CMD_ARG(get_subunit, NULL, "<address>", cmd_get_subunit_info,
+					     2, 0),
 			       SHELL_SUBCMD_SET_END);
 
 static int cmd_avrcp(const struct shell *sh, size_t argc, char **argv)