[PATCH v4] Bluetooth: hci_event: Add HCI_Write_Link_Supervision_Timeout command/event structures

[zhangchen200426@163.com]

From: Chen Zhang <zhangchen01@kylinos.cn>

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.

Changes in v4:
- Fix sparse warning: convert the timeout to little-endian with
  cpu_to_le16() when sending the command
- Use hci_rp_write_link_supervision_timeout instead of hci_ev_status in
  the command complete handler, matching the style of
  hci_cc_write_link_policy()
- Rename timeout_ms to timeout since the command parameter holds raw HCI
  slots (0.625 ms units), not milliseconds

Reported-by: kernel test robot <lkp@intel.com>
Closes: https://lore.kernel.org/oe-kbuild-all/202608080528.0kc5JCoL-lkp@intel.com/
Signed-off-by: Chen Zhang <zhangchen01@kylinos.cn>
---
 include/net/bluetooth/hci.h      | 10 ++++++++
 include/net/bluetooth/hci_core.h |  1 +
 net/bluetooth/hci_event.c        | 44 ++++++++++++++++++++++++++++++++
 3 files changed, 55 insertions(+)

diff --git a/include/net/bluetooth/hci.h b/include/net/bluetooth/hci.h
index 50f0eef71fb1..f3c91cc1fc45 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;	/* in units of 0.625 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..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 ea858391c789..0ee6d5922ca4 100644
--- a/net/bluetooth/hci_event.c
+++ b/net/bluetooth/hci_event.c
@@ -609,6 +609,37 @@ 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_rp_write_link_supervision_timeout *rp = data;
+	struct hci_cp_write_link_supervision_timeout *sent;
+	struct hci_conn *conn;
+
+	bt_dev_dbg(hdev, "status 0x%2.2x", rp->status);
+
+	if (rp->status)
+		return rp->status;
+
+	sent = hci_sent_cmd_data(hdev, HCI_OP_WRITE_LINK_SUPERVISION_TIMEOUT);
+	if (!sent)
+		return rp->status;
+
+	hci_dev_lock(hdev);
+
+	conn = hci_conn_hash_lookup_handle(hdev, __le16_to_cpu(rp->handle));
+	if (conn) {
+		conn->link_supervision_timeout = __le16_to_cpu(sent->timeout);
+		bt_dev_dbg(hdev, "handle 0x%4.4x timeout 0x%4.4x (%u ms)",
+			   __le16_to_cpu(rp->handle), conn->link_supervision_timeout,
+			   conn->link_supervision_timeout * 5 / 8);
+	}
+
+	hci_dev_unlock(hdev);
+
+	return rp->status;
+}
+
 static u8 hci_cc_read_num_supported_iac(struct hci_dev *hdev, void *data,
 					struct sk_buff *skb)
 {
@@ -3243,6 +3274,16 @@ 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 = cpu_to_le16(0x1F40);	/* 8000 * 0.625ms = 5000ms */
+			hci_send_cmd(hdev, HCI_OP_WRITE_LINK_SUPERVISION_TIMEOUT,
+				     sizeof(cp), &cp);
+		}
+
 	}
 
 	if (conn->type == ACL_LINK)
@@ -4100,6 +4141,9 @@ 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