hci_ldisc.c

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/*
 *
 *  Bluetooth HCI UART driver
 *
 *  Copyright (C) 2000-2001  Qualcomm Incorporated
 *  Copyright (C) 2002-2003  Maxim Krasnyansky <[email protected]>
 *  Copyright (C) 2004-2005  Marcel Holtmann <[email protected]>
 *
 *
 *  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)
{
    struct tty_struct *tty = hu->tty;
    struct hci_dev *hdev = hu->hdev;
    struct sk_buff *skb;

    if (test_and_set_bit(HCI_UART_SENDING, &hu->tx_state)) {
        set_bit(HCI_UART_TX_WAKEUP, &hu->tx_state);
        return 0;
    }

    BT_DBG("");

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);
    return 0;
}

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 sk_buff *skb)
{
    struct hci_dev* hdev = (struct hci_dev *) skb->dev;
    struct hci_uart *hu;

    if (!hdev) {
        BT_ERR("Frame for unknown device (hdev=NULL)");
        return -ENODEV;
    }

    if (!test_bit(HCI_RUNNING, &hdev->flags))
        return -EBUSY;

    hu = hci_get_drvdata(hdev);

    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 = (void *) tty->disc_data;

    BT_DBG("tty %p", tty);

    /* FIXME: This btw is bogus, nothing requires the old ldisc to clear
       the pointer */
    if (hu)
        return -EEXIST;

    /* 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);

    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);

    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);
    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 <[email protected]>");
MODULE_DESCRIPTION("Bluetooth HCI UART driver ver " VERSION);
MODULE_VERSION(VERSION);
MODULE_LICENSE("GPL");
MODULE_ALIAS_LDISC(N_HCI);