Update Linux to v5.4.2

Change-Id: Idf6911045d9d382da2cfe01b1edff026404ac8fd
diff --git a/drivers/bluetooth/hci_ldisc.c b/drivers/bluetooth/hci_ldisc.c
index ea6238e..85a30fb 100644
--- a/drivers/bluetooth/hci_ldisc.c
+++ b/drivers/bluetooth/hci_ldisc.c
@@ -1,3 +1,4 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
 /*
  *
  *  Bluetooth HCI UART driver
@@ -5,22 +6,6 @@
  *  Copyright (C) 2000-2001  Qualcomm Incorporated
  *  Copyright (C) 2002-2003  Maxim Krasnyansky <maxk@qualcomm.com>
  *  Copyright (C) 2004-2005  Marcel Holtmann <marcel@holtmann.org>
- *
- *
- *  This program is free software; you can redistribute it and/or modify
- *  it under the terms of the GNU General Public License as published by
- *  the Free Software Foundation; either version 2 of the License, or
- *  (at your option) any later version.
- *
- *  This program is distributed in the hope that it will be useful,
- *  but WITHOUT ANY WARRANTY; without even the implied warranty of
- *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
- *  GNU General Public License for more details.
- *
- *  You should have received a copy of the GNU General Public License
- *  along with this program; if not, write to the Free Software
- *  Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
- *
  */
 
 #include <linux/module.h>
@@ -193,6 +178,7 @@
 		goto restart;
 
 	clear_bit(HCI_UART_SENDING, &hu->tx_state);
+	wake_up_bit(&hu->tx_state, HCI_UART_SENDING);
 }
 
 void hci_uart_init_work(struct work_struct *work)
@@ -207,11 +193,11 @@
 	err = hci_register_dev(hu->hdev);
 	if (err < 0) {
 		BT_ERR("Can't register HCI device");
+		clear_bit(HCI_UART_PROTO_READY, &hu->flags);
+		hu->proto->close(hu);
 		hdev = hu->hdev;
 		hu->hdev = NULL;
 		hci_free_dev(hdev);
-		clear_bit(HCI_UART_PROTO_READY, &hu->flags);
-		hu->proto->close(hu);
 		return;
 	}
 
@@ -228,6 +214,13 @@
 	return 0;
 }
 
+int hci_uart_wait_until_sent(struct hci_uart *hu)
+{
+	return wait_on_bit_timeout(&hu->tx_state, HCI_UART_SENDING,
+				   TASK_INTERRUPTIBLE,
+				   msecs_to_jiffies(2000));
+}
+
 /* ------- Interface to HCI layer ------ */
 /* Reset device */
 static int hci_uart_flush(struct hci_dev *hdev)
@@ -299,6 +292,19 @@
 	return 0;
 }
 
+/* Check the underlying device or tty has flow control support */
+bool hci_uart_has_flow_control(struct hci_uart *hu)
+{
+	/* serdev nodes check if the needed operations are present */
+	if (hu->serdev)
+		return true;
+
+	if (hu->tty->driver->ops->tiocmget && hu->tty->driver->ops->tiocmset)
+		return true;
+
+	return false;
+}
+
 /* Flow control or un-flow control the device */
 void hci_uart_set_flow_control(struct hci_uart *hu, bool enable)
 {
@@ -616,6 +622,7 @@
 static int hci_uart_register_dev(struct hci_uart *hu)
 {
 	struct hci_dev *hdev;
+	int err;
 
 	BT_DBG("");
 
@@ -659,11 +666,22 @@
 	else
 		hdev->dev_type = HCI_PRIMARY;
 
+	/* Only call open() for the protocol after hdev is fully initialized as
+	 * open() (or a timer/workqueue it starts) may attempt to reference it.
+	 */
+	err = hu->proto->open(hu);
+	if (err) {
+		hu->hdev = NULL;
+		hci_free_dev(hdev);
+		return err;
+	}
+
 	if (test_bit(HCI_UART_INIT_PENDING, &hu->hdev_flags))
 		return 0;
 
 	if (hci_register_dev(hdev) < 0) {
 		BT_ERR("Can't register HCI device");
+		hu->proto->close(hu);
 		hu->hdev = NULL;
 		hci_free_dev(hdev);
 		return -ENODEV;
@@ -683,20 +701,14 @@
 	if (!p)
 		return -EPROTONOSUPPORT;
 
-	err = p->open(hu);
-	if (err)
-		return err;
-
 	hu->proto = p;
-	set_bit(HCI_UART_PROTO_READY, &hu->flags);
 
 	err = hci_uart_register_dev(hu);
 	if (err) {
-		clear_bit(HCI_UART_PROTO_READY, &hu->flags);
-		p->close(hu);
 		return err;
 	}
 
+	set_bit(HCI_UART_PROTO_READY, &hu->flags);
 	return 0;
 }
 
@@ -823,6 +835,7 @@
 	hci_uart_ldisc.read		= hci_uart_tty_read;
 	hci_uart_ldisc.write		= hci_uart_tty_write;
 	hci_uart_ldisc.ioctl		= hci_uart_tty_ioctl;
+	hci_uart_ldisc.compat_ioctl	= hci_uart_tty_ioctl;
 	hci_uart_ldisc.poll		= hci_uart_tty_poll;
 	hci_uart_ldisc.receive_buf	= hci_uart_tty_receive;
 	hci_uart_ldisc.write_wakeup	= hci_uart_tty_wakeup;