[PATCH 1/3] Bluetooth: btmtk: Route firmware debug event to the diag channel

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

MediaTek controllers may emit a firmware debug event on the ACL channel
using the reserved handle 0x0efd, which shows up in the ACL header as
0x2efd once the start fragment flag is included.

Neither btmtk_usb_recv_acl() nor btmtksdio_recv_acl() recognizes it, so
the packet is passed to the HCI core, which has no connection with that
handle and complains:

  Bluetooth: hci0: ACL packet for unknown connection handle 3837

Handle it the same way as the existing firmware debug logging packets and
forward it to the diagnostic channel instead.

Verified on MT7922: under the condition that triggers this firmware
debug event, it is now routed to the diag channel instead of reaching
the host as an unknown ACL packet.

Signed-off-by: Chris Lu <chris.lu@mediatek.com>
---
 drivers/bluetooth/btmtk.c     | 1 +
 drivers/bluetooth/btmtksdio.c | 1 +
 2 files changed, 2 insertions(+)

diff --git a/drivers/bluetooth/btmtk.c b/drivers/bluetooth/btmtk.c
index 660ed5b02841..5b0a131bc9d2 100644
--- a/drivers/bluetooth/btmtk.c
+++ b/drivers/bluetooth/btmtk.c
@@ -1076,6 +1076,7 @@ int btmtk_usb_recv_acl(struct hci_dev *hdev, struct sk_buff *skb)
 		fallthrough;
 	case 0x05ff:		/* Firmware debug logging 1 */
 	case 0x05fe:		/* Firmware debug logging 2 */
+	case 0x2efd:		/* Firmware debug event */
 		return hci_recv_diag(hdev, skb);
 	}

diff --git a/drivers/bluetooth/btmtksdio.c b/drivers/bluetooth/btmtksdio.c
index fe4ca9395aa3..9a1b6f9b0872 100644
--- a/drivers/bluetooth/btmtksdio.c
+++ b/drivers/bluetooth/btmtksdio.c
@@ -460,6 +460,7 @@ static int btmtksdio_recv_acl(struct hci_dev *hdev, struct sk_buff *skb)
 		fallthrough;
 	case 0x05ff:
 	case 0x05fe:
+	case 0x2efd:		/* Firmware debug event */
 		/* Firmware debug logging */
 		return hci_recv_diag(hdev, skb);
 	}
--
2.45.2