drivers/bluetooth/hci_ldisc.c - SHIFTPHONES/mainline/linux - Gitiles

 // 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;
 	}

 	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);

 	percpu_init_rwsem(&hu->proto_lock);

 	/* 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);
	// 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;
	}

	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);

	percpu_init_rwsem(&hu->proto_lock);

	/* 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);