Bluetooth: Add support for tracking transmitted packets

Protocols/profiles may want to know when exactly their PDU has been
transmitted over the air. To make this possible, introduce support for
a callback that will get called when the controller reports that a
packet has been transmitted (through the Number of Completed Packets
HCI event).

Change-Id: Ia3a19b93c5b2111f144bfabe5861187c41525f30
Signed-off-by: Johan Hedberg <johan.hedberg@intel.com>

subsys/bluetooth/host/Kconfig

@@ -161,6 +161,15 @@ config BLUETOOTH_L2CAP_TX_MTU
 	help
 	  Maximum L2CAP MTU for L2CAP TX buffers.
 
+config BLUETOOTH_CONN_TX_MAX
+	int "Maximum number of pending TX buffers"
+	default 7
+	default BLUETOOTH_CONTROLLER_TX_BUFFERS if BLUETOOTH_CONTROLLER
+	range 1 128
+	help
+	  Maximum number of pending TX buffers that have not yet
+	  been acknowledged by the controller.
+
 config BLUETOOTH_L2CAP_TX_USER_DATA_SIZE
 	int "Maximum supported user data size for L2CAP TX buffers"
 	default 4

subsys/bluetooth/host/conn.c

@@ -13,6 +13,7 @@
 #include <atomic.h>
 #include <misc/byteorder.h>
 #include <misc/util.h>
+#include <misc/slist.h>
 #include <misc/stack.h>
 #include <misc/__assert.h>
 
@@ -44,6 +45,16 @@ const struct bt_conn_auth_cb *bt_auth;
 
 static struct bt_conn conns[CONFIG_BLUETOOTH_MAX_CONN];
 static struct bt_conn_cb *callback_list;
+
+struct conn_tx_cb {
+	bt_conn_tx_cb_t cb;
+};
+
+#define conn_tx(buf) ((struct conn_tx_cb *)net_buf_user_data(buf))
+
+static struct bt_conn_tx conn_tx[CONFIG_BLUETOOTH_CONN_TX_MAX];
+static sys_slist_t free_tx = SYS_SLIST_STATIC_INIT(&free_tx);
+
 #if defined(CONFIG_BLUETOOTH_BREDR)
 static struct bt_conn sco_conns[CONFIG_BLUETOOTH_MAX_SCO_CONN];
 
@@ -1040,9 +1051,10 @@ void bt_conn_recv(struct bt_conn *conn, struct net_buf *buf, uint8_t flags)
 	bt_l2cap_recv(conn, buf);
 }
 
-int bt_conn_send(struct bt_conn *conn, struct net_buf *buf)
+int bt_conn_send_cb(struct bt_conn *conn, struct net_buf *buf,
+		    bt_conn_tx_cb_t cb)
 {
-	BT_DBG("conn handle %u buf len %u", conn->handle, buf->len);
+	BT_DBG("conn handle %u buf len %u cb %p", conn->handle, buf->len, cb);
 
 	if (buf->pool->user_data_size < BT_BUF_USER_DATA_MIN) {
 		BT_ERR("Too small user data size");
@@ -1056,14 +1068,55 @@ int bt_conn_send(struct bt_conn *conn, struct net_buf *buf)
 		return -ENOTCONN;
 	}
 
+	conn_tx(buf)->cb = cb;
+
 	net_buf_put(&conn->tx_queue, buf);
 	return 0;
 }
 
+static void tx_free(struct bt_conn_tx *tx)
+{
+	tx->cb = NULL;
+	sys_slist_prepend(&free_tx, &tx->node);
+}
+
+void bt_conn_notify_tx(struct bt_conn *conn)
+{
+	struct bt_conn_tx *tx;
+
+	BT_DBG("conn %p", conn);
+
+	while ((tx = k_fifo_get(&conn->tx_notify, K_NO_WAIT))) {
+		if (tx->cb) {
+			tx->cb(conn);
+		}
+
+		tx_free(tx);
+	}
+}
+
+static void add_pending_tx(struct bt_conn *conn, bt_conn_tx_cb_t cb)
+{
+	sys_snode_t *node;
+	unsigned int key;
+
+	BT_DBG("conn %p cb %p", conn, cb);
+
+	__ASSERT(!sys_slist_is_empty(&free_tx), "No free conn TX contexts");
+
+	node = sys_slist_get_not_empty(&free_tx);
+	CONTAINER_OF(node, struct bt_conn_tx, node)->cb = cb;
+
+	key = irq_lock();
+	sys_slist_append(&conn->tx_pending, node);
+	irq_unlock(key);
+}
+
 static bool send_frag(struct bt_conn *conn, struct net_buf *buf, uint8_t flags,
 		      bool always_consume)
 {
 	struct bt_hci_acl_hdr *hdr;
+	bt_conn_tx_cb_t cb;
 	int err;
 
 	BT_DBG("conn %p buf %p len %u flags 0x%02x", conn, buf, buf->len,
@@ -1072,6 +1125,9 @@ static bool send_frag(struct bt_conn *conn, struct net_buf *buf, uint8_t flags,
 	/* Wait until the controller can accept ACL packets */
 	k_sem_take(bt_conn_get_pkts(conn), K_FOREVER);
 
+	/* Make sure we notify and free up any pending tx contexts */
+	bt_conn_notify_tx(conn);
+
 	/* Check for disconnection while waiting for pkts_sem */
 	if (conn->state != BT_CONN_CONNECTED) {
 		goto fail;
@@ -1081,6 +1137,7 @@ static bool send_frag(struct bt_conn *conn, struct net_buf *buf, uint8_t flags,
 	hdr->handle = sys_cpu_to_le16(bt_acl_handle_pack(conn->handle, flags));
 	hdr->len = sys_cpu_to_le16(buf->len - sizeof(*hdr));
 
+	cb = conn_tx(buf)->cb;
 	bt_buf_set_type(buf, BT_BUF_ACL_OUT);
 
 	err = bt_send(buf);
@@ -1089,7 +1146,7 @@ static bool send_frag(struct bt_conn *conn, struct net_buf *buf, uint8_t flags,
 		goto fail;
 	}
 
-	conn->pending_pkts++;
+	add_pending_tx(conn, cb);
 	return true;
 
 fail:
@@ -1123,6 +1180,9 @@ static struct net_buf *create_frag(struct bt_conn *conn, struct net_buf *buf)
 		return NULL;
 	}
 
+	/* Fragments never have a TX completion callback */
+	conn_tx(frag)->cb = NULL;
+
 	frag_len = min(conn_mtu(conn), net_buf_tailroom(frag));
 
 	net_buf_add_mem(frag, buf->data, frag_len);
@@ -1181,7 +1241,7 @@ static void conn_cleanup(struct bt_conn *conn)
 		net_buf_unref(buf);
 	}
 
-	BT_ASSERT(!conn->pending_pkts);
+	__ASSERT(sys_slist_is_empty(&conn->tx_pending), "Pending TX packets");
 
 	bt_conn_reset_rx_state(conn);
 
@@ -1224,7 +1284,13 @@ int bt_conn_prepare_events(struct k_poll_event events[])
 				  K_POLL_TYPE_FIFO_DATA_AVAILABLE,
 				  K_POLL_MODE_NOTIFY_ONLY,
 				  &conn->tx_queue);
-		events[ev_count++].tag = BT_EVENT_CONN_TX;
+		events[ev_count++].tag = BT_EVENT_CONN_TX_QUEUE;
+
+		k_poll_event_init(&events[ev_count],
+				  K_POLL_TYPE_FIFO_DATA_AVAILABLE,
+				  K_POLL_MODE_NOTIFY_ONLY,
+				  &conn->tx_notify);
+		events[ev_count++].tag = BT_EVENT_CONN_TX_NOTIFY;
 	}
 
 	return ev_count;
@@ -1272,6 +1338,27 @@ struct bt_conn *bt_conn_add_le(const bt_addr_le_t *peer)
 	return conn;
 }
 
+static void process_unack_tx(struct bt_conn *conn)
+{
+	/* Return any unacknowledged packets */
+	while (1) {
+		sys_snode_t *node;
+		unsigned int key;
+
+		key = irq_lock();
+		node = sys_slist_get(&conn->tx_pending);
+		irq_unlock(key);
+
+		if (!node) {
+			break;
+		}
+
+		tx_free(CONTAINER_OF(node, struct bt_conn_tx, node));
+
+		k_sem_give(bt_conn_get_pkts(conn));
+	}
+}
+
 void bt_conn_set_state(struct bt_conn *conn, bt_conn_state_t state)
 {
 	bt_conn_state_t old_state;
@@ -1313,6 +1400,7 @@ void bt_conn_set_state(struct bt_conn *conn, bt_conn_state_t state)
 			break;
 		}
 		k_fifo_init(&conn->tx_queue);
+		k_fifo_init(&conn->tx_notify);
 		k_poll_signal(&conn_change, 0);
 
 		sys_slist_init(&conn->channels);
@@ -1334,12 +1422,7 @@ void bt_conn_set_state(struct bt_conn *conn, bt_conn_state_t state)
 		    old_state == BT_CONN_DISCONNECT) {
 			bt_l2cap_disconnected(conn);
 			notify_disconnected(conn);
-
-			/* Return any unacknowledged packets */
-			while (conn->pending_pkts) {
-				k_sem_give(bt_conn_get_pkts(conn));
-				conn->pending_pkts--;
-			}
+			process_unack_tx(conn);
 
 			/* Cancel Connection Update if it is pending */
 			if (conn->type == BT_CONN_TYPE_LE) {
@@ -1944,7 +2027,11 @@ int bt_conn_auth_pairing_confirm(struct bt_conn *conn)
 
 int bt_conn_init(void)
 {
-	int err;
+	int err, i;
+
+	for (i = 0; i < ARRAY_SIZE(conn_tx); i++) {
+		sys_slist_prepend(&free_tx, &conn_tx[i].node);
+	}
 
 	bt_att_init();
 

subsys/bluetooth/host/conn_internal.h

@@ -72,6 +72,13 @@ struct bt_conn_sco {
 };
 #endif
 
+typedef void (*bt_conn_tx_cb_t)(struct bt_conn *conn);
+
+struct bt_conn_tx {
+	sys_snode_t node;
+	bt_conn_tx_cb_t cb;
+};
+
 struct bt_conn {
 	uint16_t		handle;
 	uint8_t			type;
@@ -85,11 +92,14 @@ struct bt_conn {
 	uint8_t			encrypt;
 #endif /* CONFIG_BLUETOOTH_SMP || CONFIG_BLUETOOTH_BREDR */
 
-	uint8_t			pending_pkts;
-
 	uint16_t		rx_len;
 	struct net_buf		*rx;
 
+	/* Sent but not acknowledged TX packets */
+	sys_slist_t		tx_pending;
+	/* Acknowledged but not yet notified TX packets */
+	struct k_fifo		tx_notify;
+
 	/* Queue for outgoing ACL data */
 	struct k_fifo		tx_queue;
 
@@ -116,7 +126,13 @@ struct bt_conn {
 void bt_conn_recv(struct bt_conn *conn, struct net_buf *buf, uint8_t flags);
 
 /* Send data over a connection */
-int bt_conn_send(struct bt_conn *conn, struct net_buf *buf);
+int bt_conn_send_cb(struct bt_conn *conn, struct net_buf *buf,
+		    bt_conn_tx_cb_t cb);
+
+static inline int bt_conn_send(struct bt_conn *conn, struct net_buf *buf)
+{
+	return bt_conn_send_cb(conn, buf, NULL);
+}
 
 /* Add a new LE connection */
 struct bt_conn *bt_conn_add_le(const bt_addr_le_t *peer);
@@ -191,3 +207,4 @@ struct k_sem *bt_conn_get_pkts(struct bt_conn *conn);
 /* k_poll related helpers for the TX thread */
 int bt_conn_prepare_events(struct k_poll_event events[]);
 void bt_conn_process_tx(struct bt_conn *conn);
+void bt_conn_notify_tx(struct bt_conn *conn);

subsys/bluetooth/host/hci_core.c

@@ -13,6 +13,7 @@
 #include <errno.h>
 #include <atomic.h>
 #include <misc/util.h>
+#include <misc/slist.h>
 #include <misc/byteorder.h>
 #include <misc/stack.h>
 #include <misc/__assert.h>
@@ -489,17 +490,21 @@ static void hci_num_completed_packets(struct net_buf *buf)
 			continue;
 		}
 
-		if (conn->pending_pkts >= count) {
-			conn->pending_pkts -= count;
-		} else {
-			BT_ERR("completed packets mismatch: %u > %u",
-			       count, conn->pending_pkts);
-			conn->pending_pkts = 0;
-		}
-
 		irq_unlock(key);
 
 		while (count--) {
+			sys_snode_t *node;
+
+			key = irq_lock();
+			node = sys_slist_get(&conn->tx_pending);
+			irq_unlock(key);
+
+			if (!node) {
+				BT_ERR("packets count mismatch");
+				break;
+			}
+
+			k_fifo_put(&conn->tx_notify, node);
 			k_sem_give(bt_conn_get_pkts(conn));
 		}
 
@@ -2727,14 +2732,21 @@ static void process_events(struct k_poll_event *ev, int count)
 		case K_POLL_STATE_FIFO_DATA_AVAILABLE:
 			if (ev->tag == BT_EVENT_CMD_TX) {
 				send_cmd();
-			} else if (IS_ENABLED(CONFIG_BLUETOOTH_CONN) &&
-				   ev->tag == BT_EVENT_CONN_TX) {
+			} else if (IS_ENABLED(CONFIG_BLUETOOTH_CONN)) {
 				struct bt_conn *conn;
 
-				conn = CONTAINER_OF(ev->fifo, struct bt_conn,
+				if (ev->tag == BT_EVENT_CONN_TX_NOTIFY) {
+					conn = CONTAINER_OF(ev->fifo,
+							    struct bt_conn,
+							    tx_notify);
+					bt_conn_notify_tx(conn);
+				} else if (ev->tag == BT_EVENT_CONN_TX_QUEUE) {
+					conn = CONTAINER_OF(ev->fifo,
+							    struct bt_conn,
 							    tx_queue);
 					bt_conn_process_tx(conn);
 				}
+			}
 			break;
 		case K_POLL_STATE_NOT_READY:
 			break;
@@ -2746,8 +2758,8 @@ static void process_events(struct k_poll_event *ev, int count)
 }
 
 #if defined(CONFIG_BLUETOOTH_CONN)
-/* command FIFO + conn_change signal + MAX_CONN */
-#define EV_COUNT (2 + CONFIG_BLUETOOTH_MAX_CONN)
+/* command FIFO + conn_change signal + MAX_CONN * 2 (tx & tx_notify) */
+#define EV_COUNT (2 + (CONFIG_BLUETOOTH_MAX_CONN * 2))
 #else
 /* command FIFO */
 #define EV_COUNT 1
@@ -2854,6 +2866,8 @@ static void read_buffer_size_complete(struct net_buf *buf)
 
 	BT_DBG("ACL BR/EDR buffers: pkts %u mtu %u", pkts, bt_dev.le.mtu);
 
+	pkts = min(pkts, CONFIG_BLUETOOTH_CONN_TX_MAX);
+
 	k_sem_init(&bt_dev.le.pkts, pkts, pkts);
 }
 #endif
@@ -2862,16 +2876,19 @@ static void read_buffer_size_complete(struct net_buf *buf)
 static void le_read_buffer_size_complete(struct net_buf *buf)
 {
 	struct bt_hci_rp_le_read_buffer_size *rp = (void *)buf->data;
+	uint8_t le_max_num;
 
 	BT_DBG("status %u", rp->status);
 
 	bt_dev.le.mtu = sys_le16_to_cpu(rp->le_max_len);
-
-	if (bt_dev.le.mtu) {
-		k_sem_init(&bt_dev.le.pkts, rp->le_max_num, rp->le_max_num);
-		BT_DBG("ACL LE buffers: pkts %u mtu %u", rp->le_max_num,
-		       bt_dev.le.mtu);
+	if (!bt_dev.le.mtu) {
+		return;
 	}
+
+	BT_DBG("ACL LE buffers: pkts %u mtu %u", rp->le_max_num, bt_dev.le.mtu);
+
+	le_max_num = min(rp->le_max_num, CONFIG_BLUETOOTH_CONN_TX_MAX);
+	k_sem_init(&bt_dev.le.pkts, le_max_num, le_max_num);
 }
 #endif
 

subsys/bluetooth/host/hci_core.h

@@ -22,7 +22,8 @@
 /* k_poll event tags */
 enum {
 	BT_EVENT_CMD_TX,
-	BT_EVENT_CONN_TX,
+	BT_EVENT_CONN_TX_NOTIFY,
+	BT_EVENT_CONN_TX_QUEUE,
 };
 
 /* bt_dev flags: the flags defined here represent BT controller state */

subsys/bluetooth/host/hfp_hf.c

@@ -18,6 +18,8 @@
 #include <bluetooth/rfcomm.h>
 #include <bluetooth/hfp_hf.h>
 
+#include "hci_core.h"
+#include "conn_internal.h"
 #include "l2cap_internal.h"
 #include "rfcomm_internal.h"
 #include "at.h"

subsys/bluetooth/host/l2cap.c

@@ -464,7 +464,8 @@ struct net_buf *bt_l2cap_create_pdu(struct net_buf_pool *pool, size_t reserve)
 	return bt_conn_create_pdu(pool, sizeof(struct bt_l2cap_hdr) + reserve);
 }
 
-void bt_l2cap_send(struct bt_conn *conn, uint16_t cid, struct net_buf *buf)
+void bt_l2cap_send_cb(struct bt_conn *conn, uint16_t cid, struct net_buf *buf,
+		      bt_conn_tx_cb_t cb)
 {
 	struct bt_l2cap_hdr *hdr;
 
@@ -474,7 +475,7 @@ void bt_l2cap_send(struct bt_conn *conn, uint16_t cid, struct net_buf *buf)
 	hdr->len = sys_cpu_to_le16(buf->len - sizeof(*hdr));
 	hdr->cid = sys_cpu_to_le16(cid);
 
-	bt_conn_send(conn, buf);
+	bt_conn_send_cb(conn, buf, cb);
 }
 
 static void l2cap_send_reject(struct bt_conn *conn, uint8_t ident,

subsys/bluetooth/host/l2cap_internal.h

@@ -247,7 +247,14 @@ struct net_buf *bt_l2cap_create_pdu(struct net_buf_pool *pool, size_t reserve);
 struct net_buf *bt_l2cap_create_rsp(struct net_buf *buf, size_t reserve);
 
 /* Send L2CAP PDU over a connection */
-void bt_l2cap_send(struct bt_conn *conn, uint16_t cid, struct net_buf *buf);
+void bt_l2cap_send_cb(struct bt_conn *conn, uint16_t cid, struct net_buf *buf,
+		      bt_conn_tx_cb_t cb);
+
+static inline void bt_l2cap_send(struct bt_conn *conn, uint16_t cid,
+				 struct net_buf *buf)
+{
+	bt_l2cap_send_cb(conn, cid, buf, NULL);
+}
 
 /* Receive a new L2CAP PDU from a connection */
 void bt_l2cap_recv(struct bt_conn *conn, struct net_buf *buf);

subsys/bluetooth/host/sdp.c

@@ -17,6 +17,8 @@
 #include <bluetooth/log.h>
 #include <bluetooth/sdp.h>
 
+#include "hci_core.h"
+#include "conn_internal.h"
 #include "l2cap_internal.h"
 #include "sdp_internal.h"