Bluetooth: Check for default address of Intel USB controllers

Some Intel Bluetooth controllers come with a default address. If this
address is found, print an error to warn the user about it.

The controller is fully operational, but the danger of duplicate
Bluetooth addresses might causes issues. At least with a clear
error it becomes easier to debug these cases.
Signed-off-by: Marcel Holtmann <marcel@holtmann.org>
Signed-off-by: Johan Hedberg <johan.hedberg@intel.com>

drivers/bluetooth/btusb.c

@@ -1182,6 +1182,49 @@ static int btusb_setup_intel_patching(struct hci_dev *hdev,
 	return 0;
 }
 
+#define BDADDR_INTEL (&(bdaddr_t) {{0x00, 0x8b, 0x9e, 0x19, 0x03, 0x00}})
+
+static int btusb_check_bdaddr_intel(struct hci_dev *hdev)
+{
+	struct sk_buff *skb;
+	struct hci_rp_read_bd_addr *rp;
+
+	skb = __hci_cmd_sync(hdev, HCI_OP_READ_BD_ADDR, 0, NULL,
+			     HCI_INIT_TIMEOUT);
+	if (IS_ERR(skb)) {
+		BT_ERR("%s reading Intel device address failed (%ld)",
+		       hdev->name, PTR_ERR(skb));
+		return PTR_ERR(skb);
+	}
+
+	if (skb->len != sizeof(*rp)) {
+		BT_ERR("%s Intel device address length mismatch", hdev->name);
+		kfree_skb(skb);
+		return -EIO;
+	}
+
+	rp = (struct hci_rp_read_bd_addr *) skb->data;
+	if (rp->status) {
+		BT_ERR("%s Intel device address result failed (%02x)",
+		       hdev->name, rp->status);
+		kfree_skb(skb);
+		return -bt_to_errno(rp->status);
+	}
+
+	/* For some Intel based controllers, the default Bluetooth device
+	 * address 00:03:19:9E:8B:00 can be found. These controllers are
+	 * fully operational, but have the danger of duplicate addresses
+	 * and that in turn can cause problems with Bluetooth operation.
+	 */
+	if (!bacmp(&rp->bdaddr, BDADDR_INTEL))
+		BT_ERR("%s found Intel default device address (%pMR)",
+		       hdev->name, &rp->bdaddr);
+
+	kfree_skb(skb);
+
+	return 0;
+}
+
 static int btusb_setup_intel(struct hci_dev *hdev)
 {
 	struct sk_buff *skb;
@@ -1254,6 +1297,7 @@ static int btusb_setup_intel(struct hci_dev *hdev)
 		BT_INFO("%s: Intel device is already patched. patch num: %02x",
 			hdev->name, ver->fw_patch_num);
 		kfree_skb(skb);
+		btusb_check_bdaddr_intel(hdev);
 		return 0;
 	}
 
@@ -1266,6 +1310,7 @@ static int btusb_setup_intel(struct hci_dev *hdev)
 	fw = btusb_setup_intel_get_fw(hdev, ver);
 	if (!fw) {
 		kfree_skb(skb);
+		btusb_check_bdaddr_intel(hdev);
 		return 0;
 	}
 	fw_ptr = fw->data;
@@ -1345,6 +1390,7 @@ static int btusb_setup_intel(struct hci_dev *hdev)
 	BT_INFO("%s: Intel Bluetooth firmware patch completed and activated",
 		hdev->name);
 
+	btusb_check_bdaddr_intel(hdev);
 	return 0;
 
 exit_mfg_disable:
@@ -1359,6 +1405,8 @@ static int btusb_setup_intel(struct hci_dev *hdev)
 	kfree_skb(skb);
 
 	BT_INFO("%s: Intel Bluetooth firmware patch completed", hdev->name);
+
+	btusb_check_bdaddr_intel(hdev);
 	return 0;
 
 exit_mfg_deactivate:
@@ -1379,6 +1427,7 @@ static int btusb_setup_intel(struct hci_dev *hdev)
 	BT_INFO("%s: Intel Bluetooth firmware patch completed and deactivated",
 		hdev->name);
 
+	btusb_check_bdaddr_intel(hdev);
 	return 0;
 }