[PATCH v3] Bluetooth: hci_event: Add HCI_Write_Link_Supervision_Timeout command/event structures

From: Chen Zhang <[email protected]>

Some speakers do not actively initiate disconnection when powering off. As
a result, the central device can only wait for a timeout to disconnect,
with the default timeout being 20s. In certain scenarios, this can
significantly impact user experience. For example, a phone actively
connects to a speaker, the phone acts as the central device and the speaker
is the peripheral device. If the speaker is playing music and is then
turned off, it takes 20s before the music starts playing from the phone.

Define HCI_Write_Link_Supervision_Timeout command, event structure, and
corresponding event handler function, set the timeout to 5s after ACL
link is established.

Signed-off-by: Chen Zhang <[email protected]>
---
 include/net/bluetooth/hci.h      | 10 +++++++
 include/net/bluetooth/hci_core.h |  1 +
 net/bluetooth/hci_event.c        | 50 ++++++++++++++++++++++++++++++++
 3 files changed, 61 insertions(+)

diff --git a/include/net/bluetooth/hci.h b/include/net/bluetooth/hci.h
index 50f0eef71fb1..b82e219b286d 100644
--- a/include/net/bluetooth/hci.h
+++ b/include/net/bluetooth/hci.h
@@ -1239,6 +1239,16 @@ struct hci_cp_host_buffer_size {
 	__le16   sco_max_pkt;
 } __packed;
 
+#define HCI_OP_WRITE_LINK_SUPERVISION_TIMEOUT	0x0c37
+struct hci_cp_write_link_supervision_timeout {
+	__le16	 handle;
+	__le16	 timeout_ms;
+} __packed;
+struct hci_rp_write_link_supervision_timeout {
+	__u8	 status;
+	__le16	 handle;
+} __packed;
+
 #define HCI_OP_READ_NUM_SUPPORTED_IAC	0x0c38
 struct hci_rp_read_num_supported_iac {
 	__u8	status;
diff --git a/include/net/bluetooth/hci_core.h b/include/net/bluetooth/hci_core.h
index e7133ff87fbf..cfba8410a2a6 100644
--- a/include/net/bluetooth/hci_core.h
+++ b/include/net/bluetooth/hci_core.h
@@ -702,6 +702,7 @@ struct hci_conn {
 	__u8		le_features[248];
 	__u16		pkt_type;
 	__u16		link_policy;
+	__u16		link_supervision_timeout_ms;
 	__u8		key_type;
 	__u8		auth_type;
 	__u8		sec_level;
diff --git a/net/bluetooth/hci_event.c b/net/bluetooth/hci_event.c
index 741d658e9630..c4de1dda9979 100644
--- a/net/bluetooth/hci_event.c
+++ b/net/bluetooth/hci_event.c
@@ -606,6 +606,44 @@ static u8 hci_cc_write_voice_setting(struct hci_dev *hdev, void *data,
 	return rp->status;
 }
 
+static u8 hci_cc_write_link_supervision_timeout(struct hci_dev *hdev, void *data,
+						struct sk_buff *skb)
+{
+	struct hci_ev_status *rp = data;
+	struct hci_cp_write_link_supervision_timeout *sent;
+	struct hci_conn *conn;
+	u16 handle;
+	u8 status = rp->status;
+
+	bt_dev_dbg(hdev, "status 0x%2.2x", status);
+
+	sent = hci_sent_cmd_data(hdev, HCI_OP_WRITE_LINK_SUPERVISION_TIMEOUT);
+	if (!sent)
+		return status;
+
+	handle = le16_to_cpu(sent->handle);
+
+	hci_dev_lock(hdev);
+
+	conn = hci_conn_hash_lookup_handle(hdev, handle);
+	if (!conn) {
+		status = 0xFF;
+		goto done;
+	}
+
+	if (!status) {
+		conn->link_supervision_timeout_ms = __le16_to_cpu(sent->timeout_ms);
+		bt_dev_dbg(hdev, "handle 0x%4.4x timeout set to 0x%4.4x (%u ms)",
+			   handle, conn->link_supervision_timeout_ms,
+			   conn->link_supervision_timeout_ms * 5 / 8);
+	}
+
+done:
+	hci_dev_unlock(hdev);
+
+	return status;
+}
+
 static u8 hci_cc_read_num_supported_iac(struct hci_dev *hdev, void *data,
 					struct sk_buff *skb)
 {
@@ -3240,6 +3278,16 @@ static void hci_conn_complete_evt(struct hci_dev *hdev, void *data,
 			hci_send_cmd(hdev, HCI_OP_CHANGE_CONN_PTYPE, sizeof(cp),
 				     &cp);
 		}
+
+		if (conn->type == ACL_LINK && conn->role == HCI_ROLE_MASTER) {
+			struct hci_cp_write_link_supervision_timeout cp;
+
+			cp.handle = ev->handle;
+			cp.timeout_ms = 0x1F40;	/* 8000 * 0.625ms = 5000ms */
+			hci_send_cmd(hdev, HCI_OP_WRITE_LINK_SUPERVISION_TIMEOUT,
+				     sizeof(cp), &cp);
+		}
+
 	}
 
 	if (conn->type == ACL_LINK)
@@ -4097,6 +4145,8 @@ static const struct hci_cc {
 	HCI_CC_STATUS(HCI_OP_WRITE_CLASS_OF_DEV, hci_cc_write_class_of_dev),
 	HCI_CC(HCI_OP_READ_VOICE_SETTING, hci_cc_read_voice_setting,
 	       sizeof(struct hci_rp_read_voice_setting)),
+	HCI_CC(HCI_OP_WRITE_LINK_SUPERVISION_TIMEOUT, hci_cc_write_link_supervision_timeout,
+	       sizeof(struct hci_rp_write_link_supervision_timeout)),
 	HCI_CC_STATUS(HCI_OP_WRITE_VOICE_SETTING, hci_cc_write_voice_setting),
 	HCI_CC(HCI_OP_READ_NUM_SUPPORTED_IAC, hci_cc_read_num_supported_iac,
 	       sizeof(struct hci_rp_read_num_supported_iac)),
-- 
2.25.1