Bluetooth: btusb: Improve stability for QCA devices

WCN6855 2.1 will reset to apply firmware downloaded, so wait
a moment for reset done then go ahead to improve stability.

Signed-off-by: Zijun Hu <quic_zijuhu@quicinc.com>
Signed-off-by: Marcel Holtmann <marcel@holtmann.org>

drivers/bluetooth/btusb.c

@@ -2999,6 +2999,7 @@ static int btusb_set_bdaddr_wcn6855(struct hci_dev *hdev,
 #define QCA_PATCH_UPDATED	0x80
 #define QCA_DFU_TIMEOUT		3000
 #define QCA_FLAG_MULTI_NVM      0x80
+#define QCA_BT_RESET_WAIT_MS    100
 
 #define WCN6855_2_0_RAM_VERSION_GF 0x400c1200
 #define WCN6855_2_1_RAM_VERSION_GF 0x400c1211
@@ -3325,6 +3326,13 @@ static int btusb_setup_qca(struct hci_dev *hdev)
 		err = btusb_setup_qca_load_nvm(hdev, &ver, info);
 		if (err < 0)
 			return err;
+
+		/* WCN6855 2.1 will reset to apply firmware downloaded here, so
+		 * wait ~100ms for reset Done then go ahead, otherwise, it maybe
+		 * cause potential enable failure.
+		 */
+		if (info->rom_version == 0x00130201)
+			msleep(QCA_BT_RESET_WAIT_MS);
 	}
 
 	return 0;