[Bluetooth] Update inquiry cache from clock offset event

The HCI clock offset event contains the actual clock offset for the
connection. It is the same value that is received from an inquiry
response and it can be used to make further reconnections faster.
Signed-off-by: Marcel Holtmann <marcel@holtmann.org>

include/net/bluetooth/hci.h

@@ -576,6 +576,13 @@ struct hci_ev_rmt_version {
 	__u16    lmp_subver;
 } __attribute__ ((packed));
 
+#define HCI_EV_CLOCK_OFFSET	0x01C
+struct hci_ev_clock_offset {
+	__u8     status;
+	__u16    handle;
+	__u16    clock_offset;
+} __attribute__ ((packed));
+
 /* Internal events generated by Bluetooth stack */
 #define HCI_EV_STACK_INTERNAL	0xFD
 struct hci_ev_stack_internal {

net/bluetooth/hci_event.c

@@ -818,6 +818,30 @@ static inline void hci_link_key_notify_evt(struct hci_dev *hdev, struct sk_buff
 {
 }
 
+/* Clock Offset */
+static inline void hci_clock_offset_evt(struct hci_dev *hdev, struct sk_buff *skb)
+{
+	struct hci_ev_clock_offset *ev = (struct hci_ev_clock_offset *) skb->data;
+	struct hci_conn *conn = NULL;
+	__u16 handle = __le16_to_cpu(ev->handle);
+
+	BT_DBG("%s status %d", hdev->name, ev->status);
+
+	hci_dev_lock(hdev);
+
+	conn = hci_conn_hash_lookup_handle(hdev, handle);
+	if (conn && !ev->status) {
+		struct inquiry_entry *ie;
+
+		if ((ie = hci_inquiry_cache_lookup(hdev, &conn->dst))) {
+			ie->data.clock_offset = ev->clock_offset;
+			ie->timestamp = jiffies;
+		}
+	}
+
+	hci_dev_unlock(hdev);
+}
+
 void hci_event_packet(struct hci_dev *hdev, struct sk_buff *skb)
 {
 	struct hci_event_hdr *hdr = (struct hci_event_hdr *) skb->data;
@@ -886,6 +910,10 @@ void hci_event_packet(struct hci_dev *hdev, struct sk_buff *skb)
 		hci_link_key_notify_evt(hdev, skb);
 		break;
 
+	case HCI_EV_CLOCK_OFFSET:
+		hci_clock_offset_evt(hdev, skb);
+		break;
+
 	case HCI_EV_CMD_STATUS:
 		cs = (struct hci_ev_cmd_status *) skb->data;
 		skb_pull(skb, sizeof(cs));