/*
   *
   *  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>
   *
   *
   *  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>
  
  #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 <net/bluetooth/bluetooth.h>
  #include <net/bluetooth/hci_core.h>
  
  #include "hci_uart.h"
  
  #define VERSION "2.2"
  
  static struct hci_uart_proto *hup[HCI_UART_MAX_PROTO];
  
  int hci_uart_register_proto(struct hci_uart_proto *p)
  {
  	if (p->id >= HCI_UART_MAX_PROTO)
  		return -EINVAL;
  
  	if (hup[p->id])
  		return -EEXIST;
  
  	hup[p->id] = p;
  
  	return 0;
  }
  
  int hci_uart_unregister_proto(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 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)
  		skb = hu->proto->dequeue(hu);
  	else
  		hu->tx_skb = NULL;
  
  	return skb;
  }
  
  int hci_uart_tx_wakeup(struct hci_uart *hu)
  {
  	if (test_and_set_bit(HCI_UART_SENDING, &hu->tx_state)) {
  		set_bit(HCI_UART_TX_WAKEUP, &hu->tx_state);
  		return 0;
  	}
  
  	BT_DBG("");
  
  	schedule_work(&hu->write_work);
  
  	return 0;
  }
  
  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, bt_cb(skb)->pkt_type);
  		kfree_skb(skb);
  	}
  
  	if (test_bit(HCI_UART_TX_WAKEUP, &hu->tx_state))
  		goto restart;
  
  	clear_bit(HCI_UART_SENDING, &hu->tx_state);
  }
  
  static void hci_uart_init_work(struct work_struct *work)
  {
  	struct hci_uart *hu = container_of(work, struct hci_uart, init_ready);
  	int err;
  
  	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");
  		hci_free_dev(hu->hdev);
  		hu->hdev = NULL;
  		hu->proto->close(hu);
  	}
  
  	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;
  }
  
  /* ------- Interface to HCI layer ------ */
  /* Initialize device */
  static int hci_uart_open(struct hci_dev *hdev)
  {
  	BT_DBG("%s %p", hdev->name, hdev);
  
  	/* Nothing to do for UART driver */
  
  	set_bit(HCI_RUNNING, &hdev->flags);
  
  	return 0;
  }
  
  /* 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);
  
  	if (test_bit(HCI_UART_PROTO_SET, &hu->flags))
  		hu->proto->flush(hu);
  
  	return 0;
  }
  
  /* Close device */
  static int hci_uart_close(struct hci_dev *hdev)
  {
  	BT_DBG("hdev %p", hdev);
  
  	if (!test_and_clear_bit(HCI_RUNNING, &hdev->flags))
  		return 0;
  
  	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);
  
  	if (!test_bit(HCI_RUNNING, &hdev->flags))
  		return -EBUSY;
  
  	BT_DBG("%s: type %d len %d", hdev->name, bt_cb(skb)->pkt_type, skb->len);
  
  	hu->proto->enqueue(hu, skb);
  
  	hci_uart_tx_wakeup(hu);
  
  	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);
  
  	/* Error if the tty has no write op instead of leaving an exploitable
  	   hole */
  	if (tty->ops->write == NULL)
  		return -EOPNOTSUPP;
  
  	if (!(hu = kzalloc(sizeof(struct hci_uart), GFP_KERNEL))) {
  		BT_ERR("Can't allocate control structure");
  		return -ENFILE;
  	}
  
  	tty->disc_data = hu;
  	hu->tty = tty;
  	tty->receive_room = 65536;
  
  	INIT_WORK(&hu->init_ready, hci_uart_init_work);
  	INIT_WORK(&hu->write_work, hci_uart_write_work);
  
  	spin_lock_init(&hu->rx_lock);
  
  	/* Flush any pending characters in the driver and line discipline. */
  
  	/* FIXME: why is this needed. Note don't use ldisc_ref here as the
  	   open path is before the ldisc is referencable */
  
  	if (tty->ldisc->ops->flush_buffer)
  		tty->ldisc->ops->flush_buffer(tty);
  	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 = (void *)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);
  
  	cancel_work_sync(&hu->write_work);
  
  	if (test_and_clear_bit(HCI_UART_PROTO_SET, &hu->flags)) {
  		if (hdev) {
  			if (test_bit(HCI_UART_REGISTERED, &hu->flags))
  				hci_unregister_dev(hdev);
  			hci_free_dev(hdev);
  		}
  		hu->proto->close(hu);
  	}
  
  	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 = (void *)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_SET, &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, char *flags, int count)
  {
  	struct hci_uart *hu = (void *)tty->disc_data;
  
  	if (!hu || tty != hu->tty)
  		return;
  
  	if (!test_bit(HCI_UART_PROTO_SET, &hu->flags))
  		return;
  
  	spin_lock(&hu->rx_lock);
  	hu->proto->recv(hu, (void *) data, count);
  
  	if (hu->hdev)
  		hu->hdev->stat.byte_rx += count;
  
  	spin_unlock(&hu->rx_lock);
  
  	tty_unthrottle(tty);
  }
  
  static int hci_uart_register_dev(struct hci_uart *hu)
  {
  	struct hci_dev *hdev;
  
  	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);
  
  	hdev->open  = hci_uart_open;
  	hdev->close = hci_uart_close;
  	hdev->flush = hci_uart_flush;
  	hdev->send  = hci_uart_send_frame;
  	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_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_BREDR;
  
  	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");
  		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)
  {
  	struct hci_uart_proto *p;
  	int err;
  
  	p = hci_uart_get_proto(id);
  	if (!p)
  		return -EPROTONOSUPPORT;
  
  	err = p->open(hu);
  	if (err)
  		return err;
  
  	hu->proto = p;
  
  	err = hci_uart_register_dev(hu);
  	if (err) {
  		p->close(hu);
  		return err;
  	}
  
  	return 0;
  }
  
  /* hci_uart_tty_ioctl()
   *
   *    Process IOCTL system call for the tty device.
   *
   * Arguments:
   *
   *    tty        pointer to tty instance data
   *    file       pointer to open file object for device
   *    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, struct file * file,
  					unsigned int cmd, unsigned long arg)
  {
  	struct hci_uart *hu = (void *)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);
  				return err;
  			}
  		} else
  			return -EBUSY;
  		break;
  
  	case HCIUARTGETPROTO:
  		if (test_bit(HCI_UART_PROTO_SET, &hu->flags))
  			return hu->proto->id;
  		return -EUNATCH;
  
  	case HCIUARTGETDEVICE:
  		if (test_bit(HCI_UART_PROTO_SET, &hu->flags))
  			return hu->hdev->id;
  		return -EUNATCH;
  
  	case HCIUARTSETFLAGS:
  		if (test_bit(HCI_UART_PROTO_SET, &hu->flags))
  			return -EBUSY;
  		hu->hdev_flags = arg;
  		break;
  
  	case HCIUARTGETFLAGS:
  		return hu->hdev_flags;
  
  	default:
  		err = n_tty_ioctl_helper(tty, file, 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 __user *buf, size_t nr)
  {
  	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 unsigned int hci_uart_tty_poll(struct tty_struct *tty,
  					struct file *filp, poll_table *wait)
  {
  	return 0;
  }
  
  static int __init hci_uart_init(void)
  {
  	static struct tty_ldisc_ops hci_uart_ldisc;
  	int err;
  
  	BT_INFO("HCI UART driver ver %s", VERSION);
  
  	/* Register the tty discipline */
  
  	memset(&hci_uart_ldisc, 0, sizeof (hci_uart_ldisc));
  	hci_uart_ldisc.magic		= TTY_LDISC_MAGIC;
  	hci_uart_ldisc.name		= "n_hci";
  	hci_uart_ldisc.open		= hci_uart_tty_open;
  	hci_uart_ldisc.close		= hci_uart_tty_close;
  	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.poll		= hci_uart_tty_poll;
  	hci_uart_ldisc.receive_buf	= hci_uart_tty_receive;
  	hci_uart_ldisc.write_wakeup	= hci_uart_tty_wakeup;
  	hci_uart_ldisc.owner		= THIS_MODULE;
  
  	if ((err = tty_register_ldisc(N_HCI, &hci_uart_ldisc))) {
  		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
  
  	return 0;
  }
  
  static void __exit hci_uart_exit(void)
  {
  	int err;
  
  #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
  
  	/* Release tty registration of line discipline */
  	if ((err = tty_unregister_ldisc(N_HCI)))
  		BT_ERR("Can't unregister HCI line discipline (%d)", err);
  }
  
  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);