[PATCH v1] Bluetooth: btmtk: add event filter to filter specific event

[Chris Lu <chris.lu@mediatek.com>]

Due to some Bluetooth hosts have mechanism to detect invalid events,
causing abnormal behavior. Add a event filter to prevent debugging
events from being sent to host.

Signed-off-by: Chris Lu <chris.lu@mediatek.com>
---
 drivers/bluetooth/btmtk.c | 22 ++++++++++++++++++++++
 drivers/bluetooth/btmtk.h |  7 +++++++
 drivers/bluetooth/btusb.c |  2 ++
 3 files changed, 31 insertions(+)

diff --git a/drivers/bluetooth/btmtk.c b/drivers/bluetooth/btmtk.c
index 55516b4602db..302d6ddf9062 100644
--- a/drivers/bluetooth/btmtk.c
+++ b/drivers/bluetooth/btmtk.c
@@ -1503,6 +1503,28 @@ int btmtk_usb_shutdown(struct hci_dev *hdev)
 	return 0;
 }
 EXPORT_SYMBOL_GPL(btmtk_usb_shutdown);
+
+int btmtk_recv_event(struct hci_dev *hdev, struct sk_buff *skb)
+{
+	struct hci_event_hdr *hdr = (void *)skb->data;
+
+	if (hdr->evt == HCI_EV_CMD_COMPLETE) {
+		struct hci_ev_cmd_complete *ec;
+		u16 opcode;
+
+		ec = (void *)(skb->data + HCI_EVENT_HDR_SIZE);
+		opcode = __le16_to_cpu(ec->opcode);
+
+		/* Filter vendor opcode */
+		if (opcode == 0xfc5d) {
+			kfree_skb(skb);
+			return 0;
+		}
+	}
+
+	return hci_recv_frame(hdev, skb);
+}
+EXPORT_SYMBOL_GPL(btmtk_recv_event);
 #endif
 
 MODULE_AUTHOR("Sean Wang <sean.wang@mediatek.com>");
diff --git a/drivers/bluetooth/btmtk.h b/drivers/bluetooth/btmtk.h
index adaf385626ee..08b73927c8f3 100644
--- a/drivers/bluetooth/btmtk.h
+++ b/drivers/bluetooth/btmtk.h
@@ -218,6 +218,8 @@ int btmtk_usb_suspend(struct hci_dev *hdev);
 int btmtk_usb_setup(struct hci_dev *hdev);
 
 int btmtk_usb_shutdown(struct hci_dev *hdev);
+
+int btmtk_recv_event(struct hci_dev *hdev, struct sk_buff *skb);
 #else
 
 static inline int btmtk_set_bdaddr(struct hci_dev *hdev,
@@ -296,4 +298,9 @@ static inline int btmtk_usb_shutdown(struct hci_dev *hdev)
 {
 	return -EOPNOTSUPP;
 }
+
+static inline int btmtk_recv_event(struct hci_dev *hdev, struct sk_buff *skb)
+{
+	return -EOPNOTSUPP;
+}
 #endif
diff --git a/drivers/bluetooth/btusb.c b/drivers/bluetooth/btusb.c
index f9d515ee9124..daf8a387e660 100644
--- a/drivers/bluetooth/btusb.c
+++ b/drivers/bluetooth/btusb.c
@@ -4150,6 +4150,8 @@ static int btusb_probe(struct usb_interface *intf,
 	} else if (id->driver_info & BTUSB_MEDIATEK) {
 		/* Allocate extra space for Mediatek device */
 		priv_size += sizeof(struct btmtk_data);
+
+		data->recv_event = btmtk_recv_event;
 	}
 
 	data->recv_acl = hci_recv_frame;
-- 
2.45.2