Bluetooth: Classic: HGP_AG: change get_ongoing_call() to async mode

Change the callback `get_ongoing_call()` of the AG from synchronous to
asynchronous mode. It will help to avoid the Bluetooth host stack be
blocked in the context of callback `get_ongoing_call()`.

Add a function `bt_hfp_ag_ongoing_calls()` to set the ongoing calls and
reply the AT command `AT+CIND?` after the callback `get_ongoing_call()`
has been notified.

Add a delayable worker to avoid the AT command `AT+CIND?` never being
replied. After the time exceeds
@kconfig{CONFIG_BT_HFP_AG_GET_ONGOING_CALL_TIMEOUT}, the response of
the AT command `AT+CIND?` will be replied.

Signed-off-by: Lyle Zhu <lyle.zhu@nxp.com>

Author: lylezhu2012

include/zephyr/bluetooth/classic/hfp_ag.h

@@ -149,19 +149,23 @@ struct bt_hfp_ag_cb {
 
 	/** Get ongoing call information Callback
 	 *
-	 *  If this callback is provided it will be called whenever the response
-	 *  of the AT command `AT+CIND=?` from HF has been sent. It is used to get all
-	 *  ongoing calls one bye one from the upper layer.
-	 *  Then set the `Call`, `Call Setup`, and `Held Call` indicators and report the
-	 *  values int the response of AT command `AT+CIND?`. Then report all ongoing
-	 *  calls in the `+CLCC` response.
+	 *  If this callback is provided it will be called whenever the AT command `AT+CIND?` is
+	 *  received from HF has been sent.
+	 *  After the callback notified, the ongoing calls should be set via function
+	 *  `bt_hfp_ag_ongoing_calls()` within the timeout
+	 *  @kconfig{CONFIG_BT_HFP_AG_GET_ONGOING_CALL_TIMEOUT}.
 	 *
 	 *  @param ag HFP AG object.
-	 *  @param call Pointer to store the ongoing call information.
 	 *
-	 *  @return 0 in case of success and will get next one or negative value in case of error.
+	 *  @note The AG is in SLC establishment phase. The AG callback `connected()` is not
+	 *        notified at this time.
+	 *
+	 *  @return 0 in case of success. The response `+CIND` will be sent after the function
+	 *          `bt_hfp_ag_ongoing_calls()` called or after the time exceeds
+	 *          @kconfig{CONFIG_BT_HFP_AG_GET_ONGOING_CALL_TIMEOUT}. Or negative value in case
+	 *          of error. The response `+CIND` will be replied immediately.
 	 */
-	int (*get_ongoing_call)(struct bt_hfp_ag *ag, struct bt_hfp_ag_ongoing_call *call);
+	int (*get_ongoing_call)(struct bt_hfp_ag *ag);
 
 	/** HF memory dialing request Callback
 	 *
@@ -838,6 +842,19 @@ int bt_hfp_ag_service_availability(struct bt_hfp_ag *ag, bool available);
  */
 int bt_hfp_ag_hf_indicator(struct bt_hfp_ag *ag, enum hfp_ag_hf_indicators indicator, bool enable);
 
+/** @brief Set the ongoing calls
+ *
+ *  It is used to set the ongoing calls when AT command `AT+CIND?` is received.
+ *
+ *  @param ag HFP AG object.
+ *  @param calls Ongoing calls.
+ *  @param count Ongoing call count.
+ *
+ *  @return 0 in case of success or negative value in case of error.
+ */
+int bt_hfp_ag_ongoing_calls(struct bt_hfp_ag *ag, struct bt_hfp_ag_ongoing_call *calls,
+			    size_t count);
+
 #ifdef __cplusplus
 }
 #endif

subsys/bluetooth/host/classic/Kconfig

@@ -419,6 +419,13 @@ config BT_HFP_AG_REJECT_CALL
 	help
 	  This option enables ability to reject a call for HFP AG
 
+config BT_HFP_AG_GET_ONGOING_CALL_TIMEOUT
+	int "Timeout after the get ongoing calls callback notified (milliseconds) [EXPERIMENTAL]"
+	default 3000
+	range 1000 10000
+	help
+	  This option sets the timeout after the get ongoing calls callback notified
+
 endif # BT_HFP_AG
 
 config BT_AVDTP

subsys/bluetooth/host/classic/hfp_ag.c

@@ -1016,77 +1016,28 @@ static int bt_hfp_ag_bac_handler(struct bt_hfp_ag *ag, struct net_buf *buf)
 	return 0;
 }
 
-static void bt_hfp_ag_get_ongoing_calls(struct bt_hfp_ag *ag)
+static int bt_hfp_ag_get_ongoing_calls(struct bt_hfp_ag *ag)
 {
-	struct bt_hfp_ag_ongoing_call *call;
 	int err;
-	bool valid;
-	size_t len;
 
 	ag->ongoing_call_count = 0;
 
 	if ((bt_ag == NULL) || (bt_ag->get_ongoing_call == NULL)) {
 		LOG_DBG("No ongoing call retrieval method available");
-		return;
+		return -EINVAL;
 	}
 
-	do {
-		call = &ag->ongoing_calls[ag->ongoing_call_count];
-		memset(call, 0, sizeof(*call));
-
-		valid = true;
-
-		err = bt_ag->get_ongoing_call(ag, call);
-		if (err != 0) {
-			LOG_DBG("No ongoing call retrieved");
-			break;
-		}
-
-		len = strlen(call->number);
-		if ((len == 0) || (len >= ARRAY_SIZE(call->number))) {
-			LOG_WRN("Invalid call number");
-			break;
-		}
-
-		switch (call->status) {
-		case BT_HFP_AG_CALL_STATUS_DIALING:
-		case BT_HFP_AG_CALL_STATUS_ALERTING:
-			if (call->dir == BT_HFP_AG_CALL_DIR_INCOMING) {
-				LOG_ERR("Dialing call cannot be incoming");
-				valid = false;
-			}
-			break;
-		case BT_HFP_AG_CALL_STATUS_INCOMING:
-		case BT_HFP_AG_CALL_STATUS_WAITING:
-		case BT_HFP_AG_CALL_STATUS_INCOMING_HELD:
-			if (call->dir == BT_HFP_AG_CALL_DIR_OUTGOING) {
-				LOG_ERR("Incoming call cannot be outgoing");
-				valid = false;
-			}
-			break;
-		default:
-			break;
-		}
-
-		if (!valid) {
-			continue;
-		}
-
-		ag->ongoing_call_count++;
-	} while (ag->ongoing_call_count < ARRAY_SIZE(ag->ongoing_calls));
+	if (ag->state == BT_HFP_CONNECTED) {
+		LOG_ERR("Only works during SLC establishment phase");
+		return -EINVAL;
+	}
 
-	if (ag->ongoing_call_count > 1) {
-		switch (ag->ongoing_calls[0].status) {
-		case BT_HFP_AG_CALL_STATUS_ACTIVE:
-		case BT_HFP_AG_CALL_STATUS_HELD:
-		case BT_HFP_AG_CALL_STATUS_INCOMING_HELD:
-			break;
-		default:
-			LOG_ERR("Unexpected call status for multiple calls");
-			ag->ongoing_call_count = 1;
-			break;
-		}
+	err = bt_ag->get_ongoing_call(ag);
+	if (err != 0) {
+		LOG_DBG("No ongoing call retrieved");
 	}
+
+	return err;
 }
 
 static int bt_hfp_ag_notify_cind_value(struct bt_hfp_ag *ag)
@@ -1195,10 +1146,16 @@ static int bt_hfp_ag_cind_handler(struct bt_hfp_ag *ag, struct net_buf *buf)
 			ag_ind[BT_HFP_AG_ROAM_IND].max, ag_ind[BT_HFP_AG_BATTERY_IND].name,
 			ag_ind[BT_HFP_AG_BATTERY_IND].min, ag_ind[BT_HFP_AG_BATTERY_IND].connector,
 			ag_ind[BT_HFP_AG_BATTERY_IND].max);
-
-		bt_hfp_ag_get_ongoing_calls(ag);
 	} else {
-		err = bt_hfp_ag_notify_cind_value(ag);
+		err = bt_hfp_ag_get_ongoing_calls(ag);
+		if (err != 0) {
+			err = bt_hfp_ag_notify_cind_value(ag);
+		} else {
+			err = -EINPROGRESS;
+			atomic_set_bit(ag->flags, BT_HGP_AG_ONGOING_CALLS);
+			k_work_reschedule(&ag->ongoing_call_work,
+					  K_MSEC(CONFIG_BT_HFP_AG_GET_ONGOING_CALL_TIMEOUT));
+		}
 	}
 
 	return err;
@@ -3534,6 +3491,11 @@ static void hfp_ag_recv(struct bt_rfcomm_dlc *dlc, struct net_buf *buf)
 		}
 	}
 
+	if (err == -EINPROGRESS) {
+		LOG_DBG("OK code will be replied later");
+		return;
+	}
+
 	if ((err != 0) && atomic_test_bit(ag->flags, BT_HFP_AG_CMEE_ENABLE)) {
 		cme_err = bt_hfp_ag_get_cme_err(err);
 		err = hfp_ag_send_data(ag, NULL, NULL, "\r\n+CME ERROR:%d\r\n", (uint32_t)cme_err);
@@ -3784,6 +3746,29 @@ static void bt_ag_ringing_work(struct k_work *work)
 	(void)hfp_ag_next_step(call->ag, bt_ag_ringing_work_cb, call);
 }
 
+static void bt_ag_send_ok_code(struct bt_hfp_ag *ag)
+{
+	if (hfp_ag_send_data(ag, NULL, NULL, "\r\nOK\r\n") != 0) {
+		LOG_ERR("Failed to send OK code");
+	}
+}
+
+static void bt_ag_ongoing_call_work(struct k_work *work)
+{
+	struct k_work_delayable *dwork = k_work_delayable_from_work(work);
+	struct bt_hfp_ag *ag = CONTAINER_OF(dwork, struct bt_hfp_ag, ongoing_call_work);
+
+	LOG_DBG("");
+
+	if (!atomic_test_and_clear_bit(ag->flags, BT_HGP_AG_ONGOING_CALLS)) {
+		return;
+	}
+
+	ag->ongoing_call_count = 0;
+	bt_hfp_ag_notify_cind_value(ag);
+	bt_ag_send_ok_code(ag);
+}
+
 static K_KERNEL_STACK_MEMBER(ag_thread_stack, CONFIG_BT_HFP_AG_THREAD_STACK_SIZE);
 
 static struct bt_hfp_ag *hfp_ag_create(struct bt_conn *conn)
@@ -3881,6 +3866,8 @@ static struct bt_hfp_ag *hfp_ag_create(struct bt_conn *conn)
 
 	/* Init delay work */
 	k_work_init_delayable(&ag->tx_work, bt_ag_tx_work);
+	/* Init delay work */
+	k_work_init_delayable(&ag->ongoing_call_work, bt_ag_ongoing_call_work);
 
 	return ag;
 }
@@ -5204,3 +5191,94 @@ int bt_hfp_ag_hf_indicator(struct bt_hfp_ag *ag, enum hfp_ag_hf_indicators indic
 	return -ENOTSUP;
 #endif /* CONFIG_BT_HFP_HF_HF_INDICATORS */
 }
+
+int bt_hfp_ag_ongoing_calls(struct bt_hfp_ag *ag, struct bt_hfp_ag_ongoing_call *calls,
+			    size_t count)
+{
+	struct bt_hfp_ag_ongoing_call *call;
+	bool valid;
+	size_t len;
+	int err = -EINVAL;
+
+	LOG_DBG("");
+
+	if (ag == NULL) {
+		return -EINVAL;
+	}
+
+	if (count > ARRAY_SIZE(ag->ongoing_calls)) {
+		LOG_ERR("Out of buffer (%u > %u)", count, ARRAY_SIZE(ag->ongoing_calls));
+		return -ENOMEM;
+	}
+
+	if (!atomic_test_and_clear_bit(ag->flags, BT_HGP_AG_ONGOING_CALLS)) {
+		LOG_ERR("Cannot set ongoing calls");
+		return -ESRCH;
+	}
+
+	for (ag->ongoing_call_count = 0; ag->ongoing_call_count < count; ag->ongoing_call_count++) {
+		call = &calls[ag->ongoing_call_count];
+		valid = true;
+
+		len = strlen(call->number);
+		if ((len == 0) || (len >= ARRAY_SIZE(call->number))) {
+			LOG_WRN("Invalid call number");
+			/* Clear all calls */
+			ag->ongoing_call_count = 0;
+			goto failed;
+		}
+
+		switch (call->status) {
+		case BT_HFP_AG_CALL_STATUS_DIALING:
+		case BT_HFP_AG_CALL_STATUS_ALERTING:
+			if (call->dir == BT_HFP_AG_CALL_DIR_INCOMING) {
+				LOG_ERR("Dialing call cannot be incoming");
+				valid = false;
+			}
+			break;
+		case BT_HFP_AG_CALL_STATUS_INCOMING:
+		case BT_HFP_AG_CALL_STATUS_WAITING:
+		case BT_HFP_AG_CALL_STATUS_INCOMING_HELD:
+			if (call->dir == BT_HFP_AG_CALL_DIR_OUTGOING) {
+				LOG_ERR("Incoming call cannot be outgoing");
+				valid = false;
+			}
+			break;
+		default:
+			LOG_ERR("Invalid status");
+			valid = false;
+			break;
+		}
+
+		if (!valid) {
+			/* Clear all calls */
+			ag->ongoing_call_count = 0;
+			goto failed;
+		}
+
+		memcpy(&ag->ongoing_calls[ag->ongoing_call_count], call,
+		       sizeof(ag->ongoing_calls[ag->ongoing_call_count]));
+	}
+
+	if (ag->ongoing_call_count > 1) {
+		switch (ag->ongoing_calls[0].status) {
+		case BT_HFP_AG_CALL_STATUS_ACTIVE:
+		case BT_HFP_AG_CALL_STATUS_HELD:
+		case BT_HFP_AG_CALL_STATUS_INCOMING_HELD:
+			break;
+		default:
+			LOG_ERR("Unexpected call status for multiple calls");
+			/* Clear all calls */
+			ag->ongoing_call_count = 0;
+			goto failed;
+		}
+	}
+
+	err = 0;
+
+failed:
+	k_work_cancel_delayable(&ag->ongoing_call_work);
+	bt_hfp_ag_notify_cind_value(ag);
+	bt_ag_send_ok_code(ag);
+	return err;
+}

subsys/bluetooth/host/classic/hfp_ag_internal.h

@@ -136,6 +136,7 @@ enum {
 	BT_HFP_AG_CREATING_SCO,  /* SCO is creating */
 	BT_HFP_AG_VRE_ACTIVATE,  /* VRE is activated */
 	BT_HFP_AG_VRE_R2A,       /* HF is ready to accept audio */
+	BT_HGP_AG_ONGOING_CALLS, /* Waiting ongoing calls */
 
 	/* Total number of flags - must be at the end of the enum */
 	BT_HFP_AG_NUM_FLAGS,
@@ -239,6 +240,8 @@ struct bt_hfp_ag {
 	/* ongoing calls */
 	struct bt_hfp_ag_ongoing_call ongoing_calls[CONFIG_BT_HFP_AG_MAX_CALLS];
 	size_t ongoing_call_count;
+	/* ongoing calls work */
+	struct k_work_delayable ongoing_call_work;
 
 	/* last dialing number and type */
 	char last_number[CONFIG_BT_HFP_AG_PHONE_NUMBER_MAX_LEN + 1];