Bluetooth: Add SCO connection fallback

When initiating a transparent eSCO connection, make use of T2 settings at first try. T2 is the recommended settings from HFP 1.6 WideBand Speech. Upon connection failure, try T1 settings. When CVSD is requested and eSCO is supported, try to establish eSCO connection using S3 settings. If it fails, fallback in sequence to S2, S1, D1, D0 settings. To know which setting should be used, conn->attempt is used. It indicates the currently ongoing SCO connection attempt and can be used as the index for the fallback settings table. These setting and the fallback order are described in Bluetooth HFP 1.6 specification p. 101. Signed-off-by: Frédéric Dalleau <frederic.dalleau@linux.intel.com> Signed-off-by: Johan Hedberg <johan.hedberg@intel.com> Signed-off-by: Gustavo Padovan <gustavo.padovan@collabora.co.uk>

Bluetooth: Add SCO connection fallback
When initiating a transparent eSCO connection, make use of T2 settings at first try. T2 is the recommended settings from HFP 1.6 WideBand Speech. Upon connection failure, try T1 settings. When CVSD is requested and eSCO is supported, try to establish eSCO connection using S3 settings. If it fails, fallback in sequence to S2, S1, D1, D0 settings. To know which setting should be used, conn->attempt is used. It indicates the currently ongoing SCO connection attempt and can be used as the index for the fallback settings table. These setting and the fallback order are described in Bluetooth HFP 1.6 specification p. 101. Signed-off-by: Frédéric Dalleau <frederic.dalleau@linux.intel.com> Signed-off-by: Johan Hedberg <johan.hedberg@intel.com> Signed-off-by: Gustavo Padovan <gustavo.padovan@collabora.co.uk>
Frédéric Dalleau · Gustavo Padovan
1 parent 1a4c958cf9
Showing 3 changed files with 40 additions and 12 deletions Side-by-side Diff
include/net/bluetooth/hci_core.h
net/bluetooth/hci_conn.c
net/bluetooth/hci_event.c
@@ -570,7 +570,7 @@
 }
  
 void hci_disconnect(struct hci_conn *conn, __u8 reason);
-void hci_setup_sync(struct hci_conn *conn, __u16 handle);
+bool hci_setup_sync(struct hci_conn *conn, __u16 handle);
 void hci_sco_setup(struct hci_conn *conn, __u8 status);
  
 struct hci_conn *hci_conn_add(struct hci_dev *hdev, int type, bdaddr_t *dst);
@@ -31,6 +31,24 @@
 #include <net/bluetooth/a2mp.h>
 #include <net/bluetooth/smp.h>
  
+struct sco_param {
+	u16 pkt_type;
+	u16 max_latency;
+};
+
+static const struct sco_param sco_param_cvsd[] = {
+	{ EDR_ESCO_MASK & ~ESCO_2EV3, 0x000a }, /* S3 */
+	{ EDR_ESCO_MASK & ~ESCO_2EV3, 0x0007 }, /* S2 */
+	{ EDR_ESCO_MASK | ESCO_EV3,   0x0007 }, /* S1 */
+	{ EDR_ESCO_MASK | ESCO_HV3,   0xffff }, /* D1 */
+	{ EDR_ESCO_MASK | ESCO_HV1,   0xffff }, /* D0 */
+};
+
+static const struct sco_param sco_param_wideband[] = {
+	{ EDR_ESCO_MASK & ~ESCO_2EV3, 0x000d }, /* T2 */
+	{ EDR_ESCO_MASK | ESCO_EV3,   0x0008 }, /* T1 */
+};
+
 static void hci_le_create_connection(struct hci_conn *conn)
 {
 	struct hci_dev *hdev = conn->hdev;
  
@@ -172,10 +190,11 @@
 	hci_send_cmd(hdev, HCI_OP_ADD_SCO, sizeof(cp), &cp);
 }
  
-void hci_setup_sync(struct hci_conn *conn, __u16 handle)
+bool hci_setup_sync(struct hci_conn *conn, __u16 handle)
 {
 	struct hci_dev *hdev = conn->hdev;
 	struct hci_cp_setup_sync_conn cp;
+	const struct sco_param *param;
  
 	BT_DBG("hcon %p", conn);
  
  
  
  
  
@@ -192,19 +211,28 @@
  
 	switch (conn->setting & SCO_AIRMODE_MASK) {
 	case SCO_AIRMODE_TRANSP:
-		cp.pkt_type = __constant_cpu_to_le16(EDR_ESCO_MASK &
-						     ~ESCO_2EV3);
-		cp.max_latency = __constant_cpu_to_le16(0x000d);
+		if (conn->attempt > ARRAY_SIZE(sco_param_wideband))
+			return false;
 		cp.retrans_effort = 0x02;
+		param = &sco_param_wideband[conn->attempt - 1];
 		break;
 	case SCO_AIRMODE_CVSD:
-		cp.pkt_type = cpu_to_le16(conn->pkt_type);
-		cp.max_latency = __constant_cpu_to_le16(0xffff);
-		cp.retrans_effort = 0xff;
+		if (conn->attempt > ARRAY_SIZE(sco_param_cvsd))
+			return false;
+		cp.retrans_effort = 0x01;
+		param = &sco_param_cvsd[conn->attempt - 1];
 		break;
+	default:
+		return false;
 	}
  
-	hci_send_cmd(hdev, HCI_OP_SETUP_SYNC_CONN, sizeof(cp), &cp);
+	cp.pkt_type = __cpu_to_le16(param->pkt_type);
+	cp.max_latency = __cpu_to_le16(param->max_latency);
+
+	if (hci_send_cmd(hdev, HCI_OP_SETUP_SYNC_CONN, sizeof(cp), &cp) < 0)
+		return false;
+
+	return true;
 }
  
 void hci_le_conn_update(struct hci_conn *conn, u16 min, u16 max,
@@ -2909,11 +2909,11 @@
 	case 0x1c:	/* SCO interval rejected */
 	case 0x1a:	/* Unsupported Remote Feature */
 	case 0x1f:	/* Unspecified error */
-		if (conn->out && conn->attempt < 2) {
+		if (conn->out) {
 			conn->pkt_type = (hdev->esco_type & SCO_ESCO_MASK) |
 					(hdev->esco_type & EDR_ESCO_MASK);
-			hci_setup_sync(conn, conn->link->handle);
-			goto unlock;
+			if (hci_setup_sync(conn, conn->link->handle))
+				goto unlock;
 		}
 		/* fall through */
...	...	@@ -570,7 +570,7 @@
570	570	}
571	571
572	572	void hci_disconnect(struct hci_conn *conn, __u8 reason);
573		-void hci_setup_sync(struct hci_conn *conn, __u16 handle);
	573	+bool hci_setup_sync(struct hci_conn *conn, __u16 handle);
574	574	void hci_sco_setup(struct hci_conn *conn, __u8 status);
575	575
576	576	struct hci_conn hci_conn_add(struct hci_dev hdev, int type, bdaddr_t *dst);
...	...	@@ -31,6 +31,24 @@
31	31	#include <net/bluetooth/a2mp.h>
32	32	#include <net/bluetooth/smp.h>
33	33
	34	+struct sco_param {
	35	+ u16 pkt_type;
	36	+ u16 max_latency;
	37	+};
	38	+
	39	+static const struct sco_param sco_param_cvsd[] = {
	40	+ { EDR_ESCO_MASK & ~ESCO_2EV3, 0x000a }, /* S3 */
	41	+ { EDR_ESCO_MASK & ~ESCO_2EV3, 0x0007 }, /* S2 */
	42	+ { EDR_ESCO_MASK \| ESCO_EV3, 0x0007 }, /* S1 */
	43	+ { EDR_ESCO_MASK \| ESCO_HV3, 0xffff }, /* D1 */
	44	+ { EDR_ESCO_MASK \| ESCO_HV1, 0xffff }, /* D0 */
	45	+};
	46	+
	47	+static const struct sco_param sco_param_wideband[] = {
	48	+ { EDR_ESCO_MASK & ~ESCO_2EV3, 0x000d }, /* T2 */
	49	+ { EDR_ESCO_MASK \| ESCO_EV3, 0x0008 }, /* T1 */
	50	+};
	51	+
34	52	static void hci_le_create_connection(struct hci_conn *conn)
35	53	{
36	54	struct hci_dev *hdev = conn->hdev;
37	55
...	...	@@ -172,10 +190,11 @@
172	190	hci_send_cmd(hdev, HCI_OP_ADD_SCO, sizeof(cp), &cp);
173	191	}
174	192
175		-void hci_setup_sync(struct hci_conn *conn, __u16 handle)
	193	+bool hci_setup_sync(struct hci_conn *conn, __u16 handle)
176	194	{
177	195	struct hci_dev *hdev = conn->hdev;
178	196	struct hci_cp_setup_sync_conn cp;
	197	+ const struct sco_param *param;
179	198
180	199	BT_DBG("hcon %p", conn);
181	200
182	201
183	202
184	203
185	204
...	...	@@ -192,19 +211,28 @@
192	211
193	212	switch (conn->setting & SCO_AIRMODE_MASK) {
194	213	case SCO_AIRMODE_TRANSP:
195		- cp.pkt_type = __constant_cpu_to_le16(EDR_ESCO_MASK &
196		- ~ESCO_2EV3);
197		- cp.max_latency = __constant_cpu_to_le16(0x000d);
	214	+ if (conn->attempt > ARRAY_SIZE(sco_param_wideband))
	215	+ return false;
198	216	cp.retrans_effort = 0x02;
	217	+ param = &sco_param_wideband[conn->attempt - 1];
199	218	break;
200	219	case SCO_AIRMODE_CVSD:
201		- cp.pkt_type = cpu_to_le16(conn->pkt_type);
202		- cp.max_latency = __constant_cpu_to_le16(0xffff);
203		- cp.retrans_effort = 0xff;
	220	+ if (conn->attempt > ARRAY_SIZE(sco_param_cvsd))
	221	+ return false;
	222	+ cp.retrans_effort = 0x01;
	223	+ param = &sco_param_cvsd[conn->attempt - 1];
204	224	break;
	225	+ default:
	226	+ return false;
205	227	}
206	228
207		- hci_send_cmd(hdev, HCI_OP_SETUP_SYNC_CONN, sizeof(cp), &cp);
	229	+ cp.pkt_type = __cpu_to_le16(param->pkt_type);
	230	+ cp.max_latency = __cpu_to_le16(param->max_latency);
	231	+
	232	+ if (hci_send_cmd(hdev, HCI_OP_SETUP_SYNC_CONN, sizeof(cp), &cp) < 0)
	233	+ return false;
	234	+
	235	+ return true;
208	236	}
209	237
210	238	void hci_le_conn_update(struct hci_conn *conn, u16 min, u16 max,
...	...	@@ -2909,11 +2909,11 @@
2909	2909	case 0x1c: /* SCO interval rejected */
2910	2910	case 0x1a: /* Unsupported Remote Feature */
2911	2911	case 0x1f: /* Unspecified error */
2912		- if (conn->out && conn->attempt < 2) {
	2912	+ if (conn->out) {
2913	2913	conn->pkt_type = (hdev->esco_type & SCO_ESCO_MASK) \|
2914	2914	(hdev->esco_type & EDR_ESCO_MASK);
2915		- hci_setup_sync(conn, conn->link->handle);
2916		- goto unlock;
	2915	+ if (hci_setup_sync(conn, conn->link->handle))
	2916	+ goto unlock;
2917	2917	}
2918	2918	/* fall through */
2919	2919