Bluetooth: Add support for specifying connection parameters

Applications may want fine-grained control of connection parameters.
The two APIs to provide this through are bt_le_set_auto_conn() as well
as bt_conn_create_le().

Change-Id: If5cddbbf017b868d768d18d2a09daf4af8aa00d8
Signed-off-by: Johan Hedberg <johan.hedberg@intel.com>

include/bluetooth/bluetooth.h

@@ -157,12 +157,13 @@ int bt_le_scan_stop(void);
  *  will be re-established if connectable advertisement from peer is received.
  *
  *  @param addr Remote Bluetooth address.
- *  @param auto_conn boolean value. If true, auto connect is enabled,
+ *  @param param If non-NULL, auto connect is enabled with the given
- *  if false, auto connect is disabled.
+ *  parameters. If NULL, auto connect is disabled.
  *
  *  @return Zero on success or error code otherwise.
  */
-int bt_le_set_auto_conn(bt_addr_le_t *addr, bool auto_conn);
+int bt_le_set_auto_conn(bt_addr_le_t *addr,
+			const struct bt_le_conn_param *param);
 
 #endif /* CONFIG_BLUETOOTH_CENTRAL */
 

include/bluetooth/conn.h

@@ -28,6 +28,17 @@
 /** Opaque type representing a connection to a remote device */
 struct bt_conn;
 
+/** Connection parameters for LE connections */
+struct bt_le_conn_param {
+	uint16_t interval_min;
+	uint16_t interval_max;
+};
+
+#define BT_LE_CONN_PARAM_DEFAULT (&(struct bt_le_conn_param) { \
+				.interval_min = BT_GAP_INIT_CONN_INT_MIN, \
+				.interval_max = BT_GAP_INIT_CONN_INT_MAX, \
+				})
+
 /** @brief Increment a connection's reference count.
  *
  *  Increment the reference count of a connection object.
@@ -125,11 +136,13 @@ int bt_conn_disconnect(struct bt_conn *conn, uint8_t reason);
  *  Allows initiate new LE link to remote peer using its address.
  *  Returns a new reference that the the caller is responsible for managing.
  *
- *  @param peer Remote address.
+ *  @param peer  Remote address.
+ *  @param param Initial connection parameters.
  *
  *  @return Valid connection object on success or NULL otherwise.
  */
-struct bt_conn *bt_conn_create_le(const bt_addr_le_t *peer);
+struct bt_conn *bt_conn_create_le(const bt_addr_le_t *peer,
+				  const struct bt_le_conn_param *param);
 #endif
 
 /** Security level. */

net/bluetooth/conn.c

@@ -527,6 +527,8 @@ struct bt_conn *bt_conn_add_le(const bt_addr_le_t *peer)
 	conn->required_sec_level = BT_SECURITY_LOW;
 #endif /* CONFIG_BLUETOOTH_SMP */
 	conn->type = BT_CONN_TYPE_LE;
+	conn->le.interval_min = BT_GAP_INIT_CONN_INT_MIN;
+	conn->le.interval_max = BT_GAP_INIT_CONN_INT_MAX;
 
 	return conn;
 }
@@ -824,7 +826,8 @@ int bt_conn_disconnect(struct bt_conn *conn, uint8_t reason)
 	}
 }
 
-struct bt_conn *bt_conn_create_le(const bt_addr_le_t *peer)
+struct bt_conn *bt_conn_create_le(const bt_addr_le_t *peer,
+				  const struct bt_le_conn_param *param)
 {
 	struct bt_conn *conn;
 
@@ -836,6 +839,9 @@ struct bt_conn *bt_conn_create_le(const bt_addr_le_t *peer)
 	if (conn) {
 		switch (conn->state) {
 		case BT_CONN_CONNECT_SCAN:
+			conn->le.interval_min = param->interval_min;
+			conn->le.interval_max = param->interval_max;
+			return conn;
 		case BT_CONN_CONNECT:
 		case BT_CONN_CONNECTED:
 			return conn;
@@ -850,6 +856,9 @@ struct bt_conn *bt_conn_create_le(const bt_addr_le_t *peer)
 		return NULL;
 	}
 
+	conn->le.interval_min = param->interval_min;
+	conn->le.interval_max = param->interval_max;
+
 	bt_conn_set_state(conn, BT_CONN_CONNECT_SCAN);
 
 	bt_le_scan_update(true);

net/bluetooth/conn_internal.h

@@ -37,7 +37,11 @@ struct bt_conn_le {
 
 	bt_addr_le_t		init_addr;
 	bt_addr_le_t		resp_addr;
-	uint16_t		conn_interval;
+
+	uint16_t		interval;
+	uint16_t		interval_min;
+	uint16_t		interval_max;
+
 	uint8_t			features[8];
 };
 

net/bluetooth/hci_core.c

@@ -392,7 +392,7 @@ static void hci_num_completed_packets(struct net_buf *buf)
 	}
 }
 
-static int hci_le_create_conn(const bt_addr_le_t *addr)
+static int hci_le_create_conn(const struct bt_conn *conn)
 {
 	struct net_buf *buf;
 	struct bt_hci_cp_le_create_conn *cp;
@@ -409,9 +409,9 @@ static int hci_le_create_conn(const bt_addr_le_t *addr)
 	cp->scan_interval = sys_cpu_to_le16(BT_GAP_SCAN_FAST_INTERVAL);
 	cp->scan_window = cp->scan_interval;
 
-	bt_addr_le_copy(&cp->peer_addr, addr);
+	bt_addr_le_copy(&cp->peer_addr, &conn->le.resp_addr);
-	cp->conn_interval_max = sys_cpu_to_le16(BT_GAP_INIT_CONN_INT_MAX);
+	cp->conn_interval_min = sys_cpu_to_le16(conn->le.interval_min);
-	cp->conn_interval_min = sys_cpu_to_le16(BT_GAP_INIT_CONN_INT_MIN);
+	cp->conn_interval_max = sys_cpu_to_le16(conn->le.interval_max);
 	cp->supervision_timeout = sys_cpu_to_le16(0x07D0);
 
 	return bt_hci_cmd_send_sync(BT_HCI_OP_LE_CREATE_CONN, buf, NULL);
@@ -489,8 +489,8 @@ static int update_conn_params(struct bt_conn *conn)
 	BT_DBG("conn %p features 0x%x", conn, conn->le.features[0]);
 
 	/* Check if there's a need to update conn params */
-	if (conn->le.conn_interval >= LE_CONN_MIN_INTERVAL &&
+	if (conn->le.interval >= conn->le.interval_min &&
-	    conn->le.conn_interval <= LE_CONN_MAX_INTERVAL) {
+	    conn->le.interval <= conn->le.interval_max) {
 		return -EALREADY;
 	}
 
@@ -501,9 +501,10 @@ static int update_conn_params(struct bt_conn *conn)
 
 	if ((conn->le.features[0] & BT_HCI_LE_CONN_PARAM_REQ_PROC) &&
 	    (bt_dev.le.features[0] & BT_HCI_LE_CONN_PARAM_REQ_PROC)) {
-		return bt_conn_le_conn_update(conn, LE_CONN_MIN_INTERVAL,
+		return bt_conn_le_conn_update(conn, conn->le.interval_min,
-					     LE_CONN_MAX_INTERVAL,
+					      conn->le.interval_max,
-					     LE_CONN_LATENCY, LE_CONN_TIMEOUT);
+					      LE_CONN_LATENCY,
+					      LE_CONN_TIMEOUT);
 	}
 
 	return -EBUSY;
@@ -555,7 +556,7 @@ static void le_conn_complete(struct net_buf *buf)
 
 	conn->handle   = handle;
 	bt_addr_le_copy(&conn->le.dst, id_addr);
-	conn->le.conn_interval = sys_le16_to_cpu(evt->interval);
+	conn->le.interval = sys_le16_to_cpu(evt->interval);
 	conn->role = evt->role;
 
 	src.type = BT_ADDR_LE_PUBLIC;
@@ -699,7 +700,7 @@ static void le_conn_update_complete(struct net_buf *buf)
 	}
 
 	if (!evt->status) {
-		conn->le.conn_interval = interval;
+		conn->le.interval = interval;
 	}
 
 	/* TODO Notify about connection */
@@ -731,7 +732,9 @@ static void check_pending_conn(const bt_addr_le_t *id_addr,
 		goto done;
 	}
 
-	if (hci_le_create_conn(addr)) {
+	bt_addr_le_copy(&conn->le.resp_addr, addr);
+
+	if (hci_le_create_conn(conn)) {
 		goto done;
 	}
 
@@ -1214,7 +1217,8 @@ int bt_le_scan_update(bool fast_scan)
 }
 
 #if defined(CONFIG_BLUETOOTH_CENTRAL)
-int bt_le_set_auto_conn(bt_addr_le_t *addr, bool auto_conn)
+int bt_le_set_auto_conn(bt_addr_le_t *addr,
+			const struct bt_le_conn_param *param)
 {
 	struct bt_conn *conn;
 
@@ -1226,7 +1230,10 @@ int bt_le_set_auto_conn(bt_addr_le_t *addr, bool auto_conn)
 		}
 	}
 
-	if (auto_conn) {
+	if (param) {
+		conn->le.interval_min = param->interval_min;
+		conn->le.interval_max = param->interval_max;
+
 		if (!atomic_test_and_set_bit(conn->flags,
 					     BT_CONN_AUTO_CONNECT)) {
 			bt_conn_ref(conn);
@@ -1243,7 +1250,7 @@ int bt_le_set_auto_conn(bt_addr_le_t *addr, bool auto_conn)
 
 	if (conn->state == BT_CONN_DISCONNECTED &&
 	    atomic_test_bit(bt_dev.flags, BT_DEV_READY)) {
-		if (auto_conn) {
+		if (param) {
 			bt_conn_set_state(conn, BT_CONN_CONNECT_SCAN);
 		}
 		bt_le_scan_update(false);

net/bluetooth/hci_core.h

@@ -33,8 +33,6 @@
 #define lmp_le_capable(dev)	((dev).features[4] & BT_LMP_LE)
 
 /* LL connection parameters */
-#define LE_CONN_MIN_INTERVAL	0x0028
-#define LE_CONN_MAX_INTERVAL	0x0038
 #define LE_CONN_LATENCY		0x0000
 #define LE_CONN_TIMEOUT		0x002a
 

net/bluetooth/l2cap.c

@@ -974,8 +974,8 @@ int bt_l2cap_update_conn_param(struct bt_conn *conn)
 	hdr->len = sys_cpu_to_le16(sizeof(*req));
 
 	req = net_buf_add(buf, sizeof(*req));
-	req->min_interval = sys_cpu_to_le16(LE_CONN_MIN_INTERVAL);
+	req->min_interval = sys_cpu_to_le16(conn->le.interval_min);
-	req->max_interval = sys_cpu_to_le16(LE_CONN_MAX_INTERVAL);
+	req->max_interval = sys_cpu_to_le16(conn->le.interval_max);
 	req->latency = sys_cpu_to_le16(LE_CONN_LATENCY);
 	req->timeout = sys_cpu_to_le16(LE_CONN_TIMEOUT);
 

samples/bluetooth/central/src/main.c

@@ -130,7 +130,6 @@ static void connected(struct bt_conn *conn)
 static bool eir_found(const struct bt_eir *eir, void *user_data)
 {
 	bt_addr_le_t *addr = user_data;
-	uint16_t u16;
 	int i;
 
 	printk("[AD]: %u len %u\n", eir->type, eir->len);
@@ -138,24 +137,29 @@ static bool eir_found(const struct bt_eir *eir, void *user_data)
 	switch (eir->type) {
 	case BT_EIR_UUID16_SOME:
 	case BT_EIR_UUID16_ALL:
-		if ((eir->len - sizeof(eir->type)) % sizeof(u16) != 0) {
+		if ((eir->len - sizeof(eir->type)) % sizeof(uint16_t) != 0) {
 			printk("AD malformed\n");
 			return true;
 		}
 
-		for (i = 0; i < eir->len; i += sizeof(u16)) {
+		for (i = 0; i < eir->len; i += sizeof(uint16_t)) {
+			uint16_t u16;
+			int err;
+
 			memcpy(&u16, &eir->data[i], sizeof(u16));
-			if (sys_le16_to_cpu(u16) == BT_UUID_HRS) {
+			if (sys_le16_to_cpu(u16) != BT_UUID_HRS) {
-				int err = bt_le_scan_stop();
+				continue;
-
-				if (err) {
-					printk("Stopping scanning failed"
-						" (err %d)\n", err);
-				}
-
-				default_conn = bt_conn_create_le(addr);
-				return false;
 			}
+
+			err = bt_le_scan_stop();
+			if (err) {
+				printk("Stop LE scan failed (err %d)\n", err);
+				continue;
+			}
+
+			default_conn = bt_conn_create_le(addr,
+							 BT_LE_CONN_PARAM_DEFAULT);
+			return false;
 		}
 	}
 

samples/bluetooth/shell/src/main.c

@@ -236,7 +236,7 @@ static void cmd_connect_le(int argc, char *argv[])
 		return;
 	}
 
-	conn = bt_conn_create_le(&addr);
+	conn = bt_conn_create_le(&addr, BT_LE_CONN_PARAM_DEFAULT);
 
 	if (!conn) {
 		printk("Connection failed\n");
@@ -294,7 +294,6 @@ static void cmd_disconnect(int argc, char *argv[])
 static void cmd_auto_conn(int argc, char *argv[])
 {
 	bt_addr_le_t addr;
-	bool enable;
 	int err;
 
 	if (argc < 2) {
@@ -314,17 +313,14 @@ static void cmd_auto_conn(int argc, char *argv[])
 	}
 
 	if (argc < 4) {
-		enable = true;
+		bt_le_set_auto_conn(&addr, BT_LE_CONN_PARAM_DEFAULT);
 	} else if (!strcmp(argv[3], "on")) {
-		enable = true;
+		bt_le_set_auto_conn(&addr, BT_LE_CONN_PARAM_DEFAULT);
 	} else if (!strcmp(argv[3], "off")) {
-		enable = false;
+		bt_le_set_auto_conn(&addr, NULL);
 	} else {
 		printk("Specify \"on\" or \"off\"\n");
-		return;
 	}
-
-	bt_le_set_auto_conn(&addr, enable);
 }
 
 static void cmd_select(int argc, char *argv[])

samples/bluetooth/tester/src/gap.c

@@ -326,7 +326,8 @@ static void connect(const uint8_t *data, uint16_t len)
 	struct bt_conn *conn;
 	uint8_t status;
 
-	conn = bt_conn_create_le((bt_addr_le_t *) data);
+	conn = bt_conn_create_le((bt_addr_le_t *) data,
+				 BT_LE_CONN_PARAM_DEFAULT);
 	if (!conn) {
 		status = BTP_STATUS_FAILED;
 		goto rsp;