Adding upstream version 6.1.76.upstream/6.1.76

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

1 files changed, 932 insertions, 0 deletions

diff --git a/drivers/bluetooth/hci_ldisc.c b/drivers/bluetooth/hci_ldisc.c
new file mode 100644
index 000000000..865112e96
--- /dev/null
+++ b/drivers/bluetooth/hci_ldisc.c
@@ -0,0 +1,932 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+/*
+ *
+ *  Bluetooth HCI UART driver
+ *
+ *  Copyright (C) 2000-2001  Qualcomm Incorporated
+ *  Copyright (C) 2002-2003  Maxim Krasnyansky <maxk@qualcomm.com>
+ *  Copyright (C) 2004-2005  Marcel Holtmann <marcel@holtmann.org>
+ */
+
+#include <linux/module.h>
+
+#include <linux/kernel.h>
+#include <linux/init.h>
+#include <linux/types.h>
+#include <linux/fcntl.h>
+#include <linux/interrupt.h>
+#include <linux/ptrace.h>
+#include <linux/poll.h>
+
+#include <linux/slab.h>
+#include <linux/tty.h>
+#include <linux/errno.h>
+#include <linux/string.h>
+#include <linux/signal.h>
+#include <linux/ioctl.h>
+#include <linux/skbuff.h>
+#include <linux/firmware.h>
+#include <linux/serdev.h>
+
+#include <net/bluetooth/bluetooth.h>
+#include <net/bluetooth/hci_core.h>
+
+#include "btintel.h"
+#include "btbcm.h"
+#include "hci_uart.h"
+
+#define VERSION "2.3"
+
+static const struct hci_uart_proto *hup[HCI_UART_MAX_PROTO];
+
+int hci_uart_register_proto(const struct hci_uart_proto *p)
+{
+	if (p->id >= HCI_UART_MAX_PROTO)
+		return -EINVAL;
+
+	if (hup[p->id])
+		return -EEXIST;
+
+	hup[p->id] = p;
+
+	BT_INFO("HCI UART protocol %s registered", p->name);
+
+	return 0;
+}
+
+int hci_uart_unregister_proto(const struct hci_uart_proto *p)
+{
+	if (p->id >= HCI_UART_MAX_PROTO)
+		return -EINVAL;
+
+	if (!hup[p->id])
+		return -EINVAL;
+
+	hup[p->id] = NULL;
+
+	return 0;
+}
+
+static const struct hci_uart_proto *hci_uart_get_proto(unsigned int id)
+{
+	if (id >= HCI_UART_MAX_PROTO)
+		return NULL;
+
+	return hup[id];
+}
+
+static inline void hci_uart_tx_complete(struct hci_uart *hu, int pkt_type)
+{
+	struct hci_dev *hdev = hu->hdev;
+
+	/* Update HCI stat counters */
+	switch (pkt_type) {
+	case HCI_COMMAND_PKT:
+		hdev->stat.cmd_tx++;
+		break;
+
+	case HCI_ACLDATA_PKT:
+		hdev->stat.acl_tx++;
+		break;
+
+	case HCI_SCODATA_PKT:
+		hdev->stat.sco_tx++;
+		break;
+	}
+}
+
+static inline struct sk_buff *hci_uart_dequeue(struct hci_uart *hu)
+{
+	struct sk_buff *skb = hu->tx_skb;
+
+	if (!skb) {
+		percpu_down_read(&hu->proto_lock);
+
+		if (test_bit(HCI_UART_PROTO_READY, &hu->flags))
+			skb = hu->proto->dequeue(hu);
+
+		percpu_up_read(&hu->proto_lock);
+	} else {
+		hu->tx_skb = NULL;
+	}
+
+	return skb;
+}
+
+int hci_uart_tx_wakeup(struct hci_uart *hu)
+{
+	/* This may be called in an IRQ context, so we can't sleep. Therefore
+	 * we try to acquire the lock only, and if that fails we assume the
+	 * tty is being closed because that is the only time the write lock is
+	 * acquired. If, however, at some point in the future the write lock
+	 * is also acquired in other situations, then this must be revisited.
+	 */
+	if (!percpu_down_read_trylock(&hu->proto_lock))
+		return 0;
+
+	if (!test_bit(HCI_UART_PROTO_READY, &hu->flags))
+		goto no_schedule;
+
+	set_bit(HCI_UART_TX_WAKEUP, &hu->tx_state);
+	if (test_and_set_bit(HCI_UART_SENDING, &hu->tx_state))
+		goto no_schedule;
+
+	BT_DBG("");
+
+	schedule_work(&hu->write_work);
+
+no_schedule:
+	percpu_up_read(&hu->proto_lock);
+
+	return 0;
+}
+EXPORT_SYMBOL_GPL(hci_uart_tx_wakeup);
+
+static void hci_uart_write_work(struct work_struct *work)
+{
+	struct hci_uart *hu = container_of(work, struct hci_uart, write_work);
+	struct tty_struct *tty = hu->tty;
+	struct hci_dev *hdev = hu->hdev;
+	struct sk_buff *skb;
+
+	/* REVISIT: should we cope with bad skbs or ->write() returning
+	 * and error value ?
+	 */
+
+restart:
+	clear_bit(HCI_UART_TX_WAKEUP, &hu->tx_state);
+
+	while ((skb = hci_uart_dequeue(hu))) {
+		int len;
+
+		set_bit(TTY_DO_WRITE_WAKEUP, &tty->flags);
+		len = tty->ops->write(tty, skb->data, skb->len);
+		hdev->stat.byte_tx += len;
+
+		skb_pull(skb, len);
+		if (skb->len) {
+			hu->tx_skb = skb;
+			break;
+		}
+
+		hci_uart_tx_complete(hu, hci_skb_pkt_type(skb));
+		kfree_skb(skb);
+	}
+
+	clear_bit(HCI_UART_SENDING, &hu->tx_state);
+	if (test_bit(HCI_UART_TX_WAKEUP, &hu->tx_state))
+		goto restart;
+
+	wake_up_bit(&hu->tx_state, HCI_UART_SENDING);
+}
+
+void hci_uart_init_work(struct work_struct *work)
+{
+	struct hci_uart *hu = container_of(work, struct hci_uart, init_ready);
+	int err;
+	struct hci_dev *hdev;
+
+	if (!test_and_clear_bit(HCI_UART_INIT_PENDING, &hu->hdev_flags))
+		return;
+
+	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);
+		return;
+	}
+
+	set_bit(HCI_UART_REGISTERED, &hu->flags);
+}
+
+int hci_uart_init_ready(struct hci_uart *hu)
+{
+	if (!test_bit(HCI_UART_INIT_PENDING, &hu->hdev_flags))
+		return -EALREADY;
+
+	schedule_work(&hu->init_ready);
+
+	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)
+{
+	struct hci_uart *hu  = hci_get_drvdata(hdev);
+	struct tty_struct *tty = hu->tty;
+
+	BT_DBG("hdev %p tty %p", hdev, tty);
+
+	if (hu->tx_skb) {
+		kfree_skb(hu->tx_skb); hu->tx_skb = NULL;
+	}
+
+	/* Flush any pending characters in the driver and discipline. */
+	tty_ldisc_flush(tty);
+	tty_driver_flush_buffer(tty);
+
+	percpu_down_read(&hu->proto_lock);
+
+	if (test_bit(HCI_UART_PROTO_READY, &hu->flags))
+		hu->proto->flush(hu);
+
+	percpu_up_read(&hu->proto_lock);
+
+	return 0;
+}
+
+/* Initialize device */
+static int hci_uart_open(struct hci_dev *hdev)
+{
+	BT_DBG("%s %p", hdev->name, hdev);
+
+	/* Undo clearing this from hci_uart_close() */
+	hdev->flush = hci_uart_flush;
+
+	return 0;
+}
+
+/* Close device */
+static int hci_uart_close(struct hci_dev *hdev)
+{
+	BT_DBG("hdev %p", hdev);
+
+	hci_uart_flush(hdev);
+	hdev->flush = NULL;
+	return 0;
+}
+
+/* Send frames from HCI layer */
+static int hci_uart_send_frame(struct hci_dev *hdev, struct sk_buff *skb)
+{
+	struct hci_uart *hu = hci_get_drvdata(hdev);
+
+	BT_DBG("%s: type %d len %d", hdev->name, hci_skb_pkt_type(skb),
+	       skb->len);
+
+	percpu_down_read(&hu->proto_lock);
+
+	if (!test_bit(HCI_UART_PROTO_READY, &hu->flags)) {
+		percpu_up_read(&hu->proto_lock);
+		return -EUNATCH;
+	}
+
+	hu->proto->enqueue(hu, skb);
+	percpu_up_read(&hu->proto_lock);
+
+	hci_uart_tx_wakeup(hu);
+
+	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)
+{
+	struct tty_struct *tty = hu->tty;
+	struct ktermios ktermios;
+	int status;
+	unsigned int set = 0;
+	unsigned int clear = 0;
+
+	if (hu->serdev) {
+		serdev_device_set_flow_control(hu->serdev, !enable);
+		serdev_device_set_rts(hu->serdev, !enable);
+		return;
+	}
+
+	if (enable) {
+		/* Disable hardware flow control */
+		ktermios = tty->termios;
+		ktermios.c_cflag &= ~CRTSCTS;
+		status = tty_set_termios(tty, &ktermios);
+		BT_DBG("Disabling hardware flow control: %s",
+		       status ? "failed" : "success");
+
+		/* Clear RTS to prevent the device from sending */
+		/* Most UARTs need OUT2 to enable interrupts */
+		status = tty->driver->ops->tiocmget(tty);
+		BT_DBG("Current tiocm 0x%x", status);
+
+		set &= ~(TIOCM_OUT2 | TIOCM_RTS);
+		clear = ~set;
+		set &= TIOCM_DTR | TIOCM_RTS | TIOCM_OUT1 |
+		       TIOCM_OUT2 | TIOCM_LOOP;
+		clear &= TIOCM_DTR | TIOCM_RTS | TIOCM_OUT1 |
+			 TIOCM_OUT2 | TIOCM_LOOP;
+		status = tty->driver->ops->tiocmset(tty, set, clear);
+		BT_DBG("Clearing RTS: %s", status ? "failed" : "success");
+	} else {
+		/* Set RTS to allow the device to send again */
+		status = tty->driver->ops->tiocmget(tty);
+		BT_DBG("Current tiocm 0x%x", status);
+
+		set |= (TIOCM_OUT2 | TIOCM_RTS);
+		clear = ~set;
+		set &= TIOCM_DTR | TIOCM_RTS | TIOCM_OUT1 |
+		       TIOCM_OUT2 | TIOCM_LOOP;
+		clear &= TIOCM_DTR | TIOCM_RTS | TIOCM_OUT1 |
+			 TIOCM_OUT2 | TIOCM_LOOP;
+		status = tty->driver->ops->tiocmset(tty, set, clear);
+		BT_DBG("Setting RTS: %s", status ? "failed" : "success");
+
+		/* Re-enable hardware flow control */
+		ktermios = tty->termios;
+		ktermios.c_cflag |= CRTSCTS;
+		status = tty_set_termios(tty, &ktermios);
+		BT_DBG("Enabling hardware flow control: %s",
+		       status ? "failed" : "success");
+	}
+}
+
+void hci_uart_set_speeds(struct hci_uart *hu, unsigned int init_speed,
+			 unsigned int oper_speed)
+{
+	hu->init_speed = init_speed;
+	hu->oper_speed = oper_speed;
+}
+
+void hci_uart_set_baudrate(struct hci_uart *hu, unsigned int speed)
+{
+	struct tty_struct *tty = hu->tty;
+	struct ktermios ktermios;
+
+	ktermios = tty->termios;
+	ktermios.c_cflag &= ~CBAUD;
+	tty_termios_encode_baud_rate(&ktermios, speed, speed);
+
+	/* tty_set_termios() return not checked as it is always 0 */
+	tty_set_termios(tty, &ktermios);
+
+	BT_DBG("%s: New tty speeds: %d/%d", hu->hdev->name,
+	       tty->termios.c_ispeed, tty->termios.c_ospeed);
+}
+
+static int hci_uart_setup(struct hci_dev *hdev)
+{
+	struct hci_uart *hu = hci_get_drvdata(hdev);
+	struct hci_rp_read_local_version *ver;
+	struct sk_buff *skb;
+	unsigned int speed;
+	int err;
+
+	/* Init speed if any */
+	if (hu->init_speed)
+		speed = hu->init_speed;
+	else if (hu->proto->init_speed)
+		speed = hu->proto->init_speed;
+	else
+		speed = 0;
+
+	if (speed)
+		hci_uart_set_baudrate(hu, speed);
+
+	/* Operational speed if any */
+	if (hu->oper_speed)
+		speed = hu->oper_speed;
+	else if (hu->proto->oper_speed)
+		speed = hu->proto->oper_speed;
+	else
+		speed = 0;
+
+	if (hu->proto->set_baudrate && speed) {
+		err = hu->proto->set_baudrate(hu, speed);
+		if (!err)
+			hci_uart_set_baudrate(hu, speed);
+	}
+
+	if (hu->proto->setup)
+		return hu->proto->setup(hu);
+
+	if (!test_bit(HCI_UART_VND_DETECT, &hu->hdev_flags))
+		return 0;
+
+	skb = __hci_cmd_sync(hdev, HCI_OP_READ_LOCAL_VERSION, 0, NULL,
+			     HCI_INIT_TIMEOUT);
+	if (IS_ERR(skb)) {
+		BT_ERR("%s: Reading local version information failed (%ld)",
+		       hdev->name, PTR_ERR(skb));
+		return 0;
+	}
+
+	if (skb->len != sizeof(*ver)) {
+		BT_ERR("%s: Event length mismatch for version information",
+		       hdev->name);
+		goto done;
+	}
+
+	ver = (struct hci_rp_read_local_version *)skb->data;
+
+	switch (le16_to_cpu(ver->manufacturer)) {
+#ifdef CONFIG_BT_HCIUART_INTEL
+	case 2:
+		hdev->set_bdaddr = btintel_set_bdaddr;
+		btintel_check_bdaddr(hdev);
+		break;
+#endif
+#ifdef CONFIG_BT_HCIUART_BCM
+	case 15:
+		hdev->set_bdaddr = btbcm_set_bdaddr;
+		btbcm_check_bdaddr(hdev);
+		break;
+#endif
+	default:
+		break;
+	}
+
+done:
+	kfree_skb(skb);
+	return 0;
+}
+
+/* ------ LDISC part ------ */
+/* hci_uart_tty_open
+ *
+ *     Called when line discipline changed to HCI_UART.
+ *
+ * Arguments:
+ *     tty    pointer to tty info structure
+ * Return Value:
+ *     0 if success, otherwise error code
+ */
+static int hci_uart_tty_open(struct tty_struct *tty)
+{
+	struct hci_uart *hu;
+
+	BT_DBG("tty %p", tty);
+
+	if (!capable(CAP_NET_ADMIN))
+		return -EPERM;
+
+	/* Error if the tty has no write op instead of leaving an exploitable
+	 * hole
+	 */
+	if (tty->ops->write == NULL)
+		return -EOPNOTSUPP;
+
+	hu = kzalloc(sizeof(struct hci_uart), GFP_KERNEL);
+	if (!hu) {
+		BT_ERR("Can't allocate control structure");
+		return -ENFILE;
+	}
+	if (percpu_init_rwsem(&hu->proto_lock)) {
+		BT_ERR("Can't allocate semaphore structure");
+		kfree(hu);
+		return -ENOMEM;
+	}
+
+	tty->disc_data = hu;
+	hu->tty = tty;
+	tty->receive_room = 65536;
+
+	/* disable alignment support by default */
+	hu->alignment = 1;
+	hu->padding = 0;
+
+	INIT_WORK(&hu->init_ready, hci_uart_init_work);
+	INIT_WORK(&hu->write_work, hci_uart_write_work);
+
+	/* Flush any pending characters in the driver */
+	tty_driver_flush_buffer(tty);
+
+	return 0;
+}
+
+/* hci_uart_tty_close()
+ *
+ *    Called when the line discipline is changed to something
+ *    else, the tty is closed, or the tty detects a hangup.
+ */
+static void hci_uart_tty_close(struct tty_struct *tty)
+{
+	struct hci_uart *hu = tty->disc_data;
+	struct hci_dev *hdev;
+
+	BT_DBG("tty %p", tty);
+
+	/* Detach from the tty */
+	tty->disc_data = NULL;
+
+	if (!hu)
+		return;
+
+	hdev = hu->hdev;
+	if (hdev)
+		hci_uart_close(hdev);
+
+	if (test_bit(HCI_UART_PROTO_READY, &hu->flags)) {
+		percpu_down_write(&hu->proto_lock);
+		clear_bit(HCI_UART_PROTO_READY, &hu->flags);
+		percpu_up_write(&hu->proto_lock);
+
+		cancel_work_sync(&hu->init_ready);
+		cancel_work_sync(&hu->write_work);
+
+		if (hdev) {
+			if (test_bit(HCI_UART_REGISTERED, &hu->flags))
+				hci_unregister_dev(hdev);
+			hci_free_dev(hdev);
+		}
+		hu->proto->close(hu);
+	}
+	clear_bit(HCI_UART_PROTO_SET, &hu->flags);
+
+	percpu_free_rwsem(&hu->proto_lock);
+
+	kfree(hu);
+}
+
+/* hci_uart_tty_wakeup()
+ *
+ *    Callback for transmit wakeup. Called when low level
+ *    device driver can accept more send data.
+ *
+ * Arguments:        tty    pointer to associated tty instance data
+ * Return Value:    None
+ */
+static void hci_uart_tty_wakeup(struct tty_struct *tty)
+{
+	struct hci_uart *hu = tty->disc_data;
+
+	BT_DBG("");
+
+	if (!hu)
+		return;
+
+	clear_bit(TTY_DO_WRITE_WAKEUP, &tty->flags);
+
+	if (tty != hu->tty)
+		return;
+
+	if (test_bit(HCI_UART_PROTO_READY, &hu->flags))
+		hci_uart_tx_wakeup(hu);
+}
+
+/* hci_uart_tty_receive()
+ *
+ *     Called by tty low level driver when receive data is
+ *     available.
+ *
+ * Arguments:  tty          pointer to tty isntance data
+ *             data         pointer to received data
+ *             flags        pointer to flags for data
+ *             count        count of received data in bytes
+ *
+ * Return Value:    None
+ */
+static void hci_uart_tty_receive(struct tty_struct *tty, const u8 *data,
+				 const char *flags, int count)
+{
+	struct hci_uart *hu = tty->disc_data;
+
+	if (!hu || tty != hu->tty)
+		return;
+
+	percpu_down_read(&hu->proto_lock);
+
+	if (!test_bit(HCI_UART_PROTO_READY, &hu->flags)) {
+		percpu_up_read(&hu->proto_lock);
+		return;
+	}
+
+	/* It does not need a lock here as it is already protected by a mutex in
+	 * tty caller
+	 */
+	hu->proto->recv(hu, data, count);
+	percpu_up_read(&hu->proto_lock);
+
+	if (hu->hdev)
+		hu->hdev->stat.byte_rx += count;
+
+	tty_unthrottle(tty);
+}
+
+static int hci_uart_register_dev(struct hci_uart *hu)
+{
+	struct hci_dev *hdev;
+	int err;
+
+	BT_DBG("");
+
+	/* Initialize and register HCI device */
+	hdev = hci_alloc_dev();
+	if (!hdev) {
+		BT_ERR("Can't allocate HCI device");
+		return -ENOMEM;
+	}
+
+	hu->hdev = hdev;
+
+	hdev->bus = HCI_UART;
+	hci_set_drvdata(hdev, hu);
+
+	/* Only when vendor specific setup callback is provided, consider
+	 * the manufacturer information valid. This avoids filling in the
+	 * value for Ericsson when nothing is specified.
+	 */
+	if (hu->proto->setup)
+		hdev->manufacturer = hu->proto->manufacturer;
+
+	hdev->open  = hci_uart_open;
+	hdev->close = hci_uart_close;
+	hdev->flush = hci_uart_flush;
+	hdev->send  = hci_uart_send_frame;
+	hdev->setup = hci_uart_setup;
+	SET_HCIDEV_DEV(hdev, hu->tty->dev);
+
+	if (test_bit(HCI_UART_RAW_DEVICE, &hu->hdev_flags))
+		set_bit(HCI_QUIRK_RAW_DEVICE, &hdev->quirks);
+
+	if (test_bit(HCI_UART_EXT_CONFIG, &hu->hdev_flags))
+		set_bit(HCI_QUIRK_EXTERNAL_CONFIG, &hdev->quirks);
+
+	if (!test_bit(HCI_UART_RESET_ON_INIT, &hu->hdev_flags))
+		set_bit(HCI_QUIRK_RESET_ON_CLOSE, &hdev->quirks);
+
+	if (test_bit(HCI_UART_CREATE_AMP, &hu->hdev_flags))
+		hdev->dev_type = HCI_AMP;
+	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;
+	}
+
+	set_bit(HCI_UART_REGISTERED, &hu->flags);
+
+	return 0;
+}
+
+static int hci_uart_set_proto(struct hci_uart *hu, int id)
+{
+	const struct hci_uart_proto *p;
+	int err;
+
+	p = hci_uart_get_proto(id);
+	if (!p)
+		return -EPROTONOSUPPORT;
+
+	hu->proto = p;
+
+	err = hci_uart_register_dev(hu);
+	if (err) {
+		return err;
+	}
+
+	set_bit(HCI_UART_PROTO_READY, &hu->flags);
+	return 0;
+}
+
+static int hci_uart_set_flags(struct hci_uart *hu, unsigned long flags)
+{
+	unsigned long valid_flags = BIT(HCI_UART_RAW_DEVICE) |
+				    BIT(HCI_UART_RESET_ON_INIT) |
+				    BIT(HCI_UART_CREATE_AMP) |
+				    BIT(HCI_UART_INIT_PENDING) |
+				    BIT(HCI_UART_EXT_CONFIG) |
+				    BIT(HCI_UART_VND_DETECT);
+
+	if (flags & ~valid_flags)
+		return -EINVAL;
+
+	hu->hdev_flags = flags;
+
+	return 0;
+}
+
+/* hci_uart_tty_ioctl()
+ *
+ *    Process IOCTL system call for the tty device.
+ *
+ * Arguments:
+ *
+ *    tty        pointer to tty instance data
+ *    cmd        IOCTL command code
+ *    arg        argument for IOCTL call (cmd dependent)
+ *
+ * Return Value:    Command dependent
+ */
+static int hci_uart_tty_ioctl(struct tty_struct *tty, unsigned int cmd,
+			      unsigned long arg)
+{
+	struct hci_uart *hu = tty->disc_data;
+	int err = 0;
+
+	BT_DBG("");
+
+	/* Verify the status of the device */
+	if (!hu)
+		return -EBADF;
+
+	switch (cmd) {
+	case HCIUARTSETPROTO:
+		if (!test_and_set_bit(HCI_UART_PROTO_SET, &hu->flags)) {
+			err = hci_uart_set_proto(hu, arg);
+			if (err)
+				clear_bit(HCI_UART_PROTO_SET, &hu->flags);
+		} else
+			err = -EBUSY;
+		break;
+
+	case HCIUARTGETPROTO:
+		if (test_bit(HCI_UART_PROTO_SET, &hu->flags))
+			err = hu->proto->id;
+		else
+			err = -EUNATCH;
+		break;
+
+	case HCIUARTGETDEVICE:
+		if (test_bit(HCI_UART_REGISTERED, &hu->flags))
+			err = hu->hdev->id;
+		else
+			err = -EUNATCH;
+		break;
+
+	case HCIUARTSETFLAGS:
+		if (test_bit(HCI_UART_PROTO_SET, &hu->flags))
+			err = -EBUSY;
+		else
+			err = hci_uart_set_flags(hu, arg);
+		break;
+
+	case HCIUARTGETFLAGS:
+		err = hu->hdev_flags;
+		break;
+
+	default:
+		err = n_tty_ioctl_helper(tty, cmd, arg);
+		break;
+	}
+
+	return err;
+}
+
+/*
+ * We don't provide read/write/poll interface for user space.
+ */
+static ssize_t hci_uart_tty_read(struct tty_struct *tty, struct file *file,
+				 unsigned char *buf, size_t nr,
+				 void **cookie, unsigned long offset)
+{
+	return 0;
+}
+
+static ssize_t hci_uart_tty_write(struct tty_struct *tty, struct file *file,
+				  const unsigned char *data, size_t count)
+{
+	return 0;
+}
+
+static __poll_t hci_uart_tty_poll(struct tty_struct *tty,
+				      struct file *filp, poll_table *wait)
+{
+	return 0;
+}
+
+static struct tty_ldisc_ops hci_uart_ldisc = {
+	.owner		= THIS_MODULE,
+	.num		= N_HCI,
+	.name		= "n_hci",
+	.open		= hci_uart_tty_open,
+	.close		= hci_uart_tty_close,
+	.read		= hci_uart_tty_read,
+	.write		= hci_uart_tty_write,
+	.ioctl		= hci_uart_tty_ioctl,
+	.compat_ioctl	= hci_uart_tty_ioctl,
+	.poll		= hci_uart_tty_poll,
+	.receive_buf	= hci_uart_tty_receive,
+	.write_wakeup	= hci_uart_tty_wakeup,
+};
+
+static int __init hci_uart_init(void)
+{
+	int err;
+
+	BT_INFO("HCI UART driver ver %s", VERSION);
+
+	/* Register the tty discipline */
+	err = tty_register_ldisc(&hci_uart_ldisc);
+	if (err) {
+		BT_ERR("HCI line discipline registration failed. (%d)", err);
+		return err;
+	}
+
+#ifdef CONFIG_BT_HCIUART_H4
+	h4_init();
+#endif
+#ifdef CONFIG_BT_HCIUART_BCSP
+	bcsp_init();
+#endif
+#ifdef CONFIG_BT_HCIUART_LL
+	ll_init();
+#endif
+#ifdef CONFIG_BT_HCIUART_ATH3K
+	ath_init();
+#endif
+#ifdef CONFIG_BT_HCIUART_3WIRE
+	h5_init();
+#endif
+#ifdef CONFIG_BT_HCIUART_INTEL
+	intel_init();
+#endif
+#ifdef CONFIG_BT_HCIUART_BCM
+	bcm_init();
+#endif
+#ifdef CONFIG_BT_HCIUART_QCA
+	qca_init();
+#endif
+#ifdef CONFIG_BT_HCIUART_AG6XX
+	ag6xx_init();
+#endif
+#ifdef CONFIG_BT_HCIUART_MRVL
+	mrvl_init();
+#endif
+
+	return 0;
+}
+
+static void __exit hci_uart_exit(void)
+{
+#ifdef CONFIG_BT_HCIUART_H4
+	h4_deinit();
+#endif
+#ifdef CONFIG_BT_HCIUART_BCSP
+	bcsp_deinit();
+#endif
+#ifdef CONFIG_BT_HCIUART_LL
+	ll_deinit();
+#endif
+#ifdef CONFIG_BT_HCIUART_ATH3K
+	ath_deinit();
+#endif
+#ifdef CONFIG_BT_HCIUART_3WIRE
+	h5_deinit();
+#endif
+#ifdef CONFIG_BT_HCIUART_INTEL
+	intel_deinit();
+#endif
+#ifdef CONFIG_BT_HCIUART_BCM
+	bcm_deinit();
+#endif
+#ifdef CONFIG_BT_HCIUART_QCA
+	qca_deinit();
+#endif
+#ifdef CONFIG_BT_HCIUART_AG6XX
+	ag6xx_deinit();
+#endif
+#ifdef CONFIG_BT_HCIUART_MRVL
+	mrvl_deinit();
+#endif
+
+	tty_unregister_ldisc(&hci_uart_ldisc);
+}
+
+module_init(hci_uart_init);
+module_exit(hci_uart_exit);
+
+MODULE_AUTHOR("Marcel Holtmann <marcel@holtmann.org>");
+MODULE_DESCRIPTION("Bluetooth HCI UART driver ver " VERSION);
+MODULE_VERSION(VERSION);
+MODULE_LICENSE("GPL");
+MODULE_ALIAS_LDISC(N_HCI);