Subject: [PATCH v2 3/4] Bluetooth: qca: fix device-address endianness

From: Johan Hovold <[email-masked]>
Date: Mon, 18 Mar 2024 12:08:54 +0100

The WCN6855 firmware on the Lenovo ThinkPad X13s expects the Bluetooth
device address in big-endian order when setting it using the
EDL_WRITE_BD_ADDR_OPCODE command.

Presumably, this is the case for all non-ROME devices which all use the
EDL_WRITE_BD_ADDR_OPCODE command for this (unlike the ROME devices which
use a different command and expect the address in little-endian order).

Reverse the little-endian address before setting it to make sure that
the address can be configured using tools like btmgmt or using the
'local-bd-address' devicetree property.

Note that this can potentially break systems with boot firmware which
has started relying on the broken behaviour and is incorrectly passing
the address via devicetree in big-endian order.

Fixes: 5c0a1001c8be ("Bluetooth: hci_qca: Add helper to set device address")
Cc: [email-masked]      # 5.1
Cc: Balakrishna Godavarthi <[email-masked]>
Cc: Matthias Kaehlcke <[email-masked]>
Tested-by: Nikita Travkin <[email-masked]> # sc7180
Signed-off-by: Johan Hovold <[email-masked]>
---
 drivers/bluetooth/btqca.c | 8 ++++++--
 1 file changed, 6 insertions(+), 2 deletions(-)

diff --git a/drivers/bluetooth/btqca.c b/drivers/bluetooth/btqca.c
index b40b32fa7f1c..19cfc342fc7b 100644
--- a/drivers/bluetooth/btqca.c
+++ b/drivers/bluetooth/btqca.c
@@ -826,11 +826,15 @@ EXPORT_SYMBOL_GPL(qca_uart_setup);
 
 int qca_set_bdaddr(struct hci_dev *hdev, const bdaddr_t *bdaddr)
 {
+	bdaddr_t bdaddr_swapped;
 	struct sk_buff *skb;
 	int err;
 
-	skb = __hci_cmd_sync_ev(hdev, EDL_WRITE_BD_ADDR_OPCODE, 6, bdaddr,
-				HCI_EV_VENDOR, HCI_INIT_TIMEOUT);
+	baswap(&bdaddr_swapped, bdaddr);
+
+	skb = __hci_cmd_sync_ev(hdev, EDL_WRITE_BD_ADDR_OPCODE, 6,
+				&bdaddr_swapped, HCI_EV_VENDOR,
+				HCI_INIT_TIMEOUT);
 	if (IS_ERR(skb)) {
 		err = PTR_ERR(skb);
 		bt_dev_err(hdev, "QCA Change address cmd failed (%d)", err);
-- 
2.43.2