[PATCH v2] 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 power off. As
a result, the center 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, if a speaker is playing music and
is then turned off, it takes 20s before the music starts playing from
the center.

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..18a5a17eb218 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;
+} __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..866903a9b5c8 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;
 	__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..653184d0dfc7 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 = __le16_to_cpu(sent->timeout);
+		bt_dev_dbg(hdev, "handle 0x%4.4x timeout set to 0x%4.4x (%u ms)",
+			   handle, conn->link_supervision_timeout,
+			   conn->link_supervision_timeout * 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 = 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