interface.c

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/*
 * interface to user space for the gigaset driver
 *
 * Copyright (c) 2004 by Hansjoerg Lipp <[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.
 * =====================================================================
 */

#include "gigaset.h"
#include <linux/gigaset_dev.h>
#include <linux/tty_flip.h>
#include <linux/module.h>

/*** our ioctls ***/

static int if_lock(struct cardstate *cs, int *arg)
{
    int cmd = *arg;

    gig_dbg(DEBUG_IF, "%u: if_lock (%d)", cs->minor_index, cmd);

    if (cmd > 1)
        return -EINVAL;

    if (cmd < 0) {
        *arg = cs->mstate == MS_LOCKED;
        return 0;
    }

    if (!cmd && cs->mstate == MS_LOCKED && cs->connected) {
        cs->ops->set_modem_ctrl(cs, 0, TIOCM_DTR | TIOCM_RTS);
        cs->ops->baud_rate(cs, B115200);
        cs->ops->set_line_ctrl(cs, CS8);
        cs->control_state = TIOCM_DTR | TIOCM_RTS;
    }

    cs->waiting = 1;
    if (!gigaset_add_event(cs, &cs->at_state, EV_IF_LOCK,
                   NULL, cmd, NULL)) {
        cs->waiting = 0;
        return -ENOMEM;
    }
    gigaset_schedule_event(cs);

    wait_event(cs->waitqueue, !cs->waiting);

    if (cs->cmd_result >= 0) {
        *arg = cs->cmd_result;
        return 0;
    }

    return cs->cmd_result;
}

static int if_version(struct cardstate *cs, unsigned arg[4])
{
    static const unsigned version[4] = GIG_VERSION;
    static const unsigned compat[4] = GIG_COMPAT;
    unsigned cmd = arg[0];

    gig_dbg(DEBUG_IF, "%u: if_version (%d)", cs->minor_index, cmd);

    switch (cmd) {
    case GIGVER_DRIVER:
        memcpy(arg, version, sizeof version);
        return 0;
    case GIGVER_COMPAT:
        memcpy(arg, compat, sizeof compat);
        return 0;
    case GIGVER_FWBASE:
        cs->waiting = 1;
        if (!gigaset_add_event(cs, &cs->at_state, EV_IF_VER,
                       NULL, 0, arg)) {
            cs->waiting = 0;
            return -ENOMEM;
        }
        gigaset_schedule_event(cs);

        wait_event(cs->waitqueue, !cs->waiting);

        if (cs->cmd_result >= 0)
            return 0;

        return cs->cmd_result;
    default:
        return -EINVAL;
    }
}

static int if_config(struct cardstate *cs, int *arg)
{
    gig_dbg(DEBUG_IF, "%u: if_config (%d)", cs->minor_index, *arg);

    if (*arg != 1)
        return -EINVAL;

    if (cs->mstate != MS_LOCKED)
        return -EBUSY;

    if (!cs->connected) {
        pr_err("%s: not connected\n", __func__);
        return -ENODEV;
    }

    *arg = 0;
    return gigaset_enterconfigmode(cs);
}

/*** the terminal driver ***/
/* stolen from usbserial and some other tty drivers */

static int  if_open(struct tty_struct *tty, struct file *filp);
static void if_close(struct tty_struct *tty, struct file *filp);
static int  if_ioctl(struct tty_struct *tty,
             unsigned int cmd, unsigned long arg);
static int  if_write_room(struct tty_struct *tty);
static int  if_chars_in_buffer(struct tty_struct *tty);
static void if_throttle(struct tty_struct *tty);
static void if_unthrottle(struct tty_struct *tty);
static void if_set_termios(struct tty_struct *tty, struct ktermios *old);
static int  if_tiocmget(struct tty_struct *tty);
static int  if_tiocmset(struct tty_struct *tty,
            unsigned int set, unsigned int clear);
static int  if_write(struct tty_struct *tty,
             const unsigned char *buf, int count);

static const struct tty_operations if_ops = {
    .open =         if_open,
    .close =        if_close,
    .ioctl =        if_ioctl,
    .write =        if_write,
    .write_room =       if_write_room,
    .chars_in_buffer =  if_chars_in_buffer,
    .set_termios =      if_set_termios,
    .throttle =     if_throttle,
    .unthrottle =       if_unthrottle,
    .tiocmget =     if_tiocmget,
    .tiocmset =     if_tiocmset,
};

static int if_open(struct tty_struct *tty, struct file *filp)
{
    struct cardstate *cs;

    gig_dbg(DEBUG_IF, "%d+%d: %s()",
        tty->driver->minor_start, tty->index, __func__);

    cs = gigaset_get_cs_by_tty(tty);
    if (!cs || !try_module_get(cs->driver->owner))
        return -ENODEV;

    if (mutex_lock_interruptible(&cs->mutex)) {
        module_put(cs->driver->owner);
        return -ERESTARTSYS;
    }
    tty->driver_data = cs;

    ++cs->port.count;

    if (cs->port.count == 1) {
        tty_port_tty_set(&cs->port, tty);
        tty->low_latency = 1;
    }

    mutex_unlock(&cs->mutex);
    return 0;
}

static void if_close(struct tty_struct *tty, struct file *filp)
{
    struct cardstate *cs = tty->driver_data;

    if (!cs) { /* happens if we didn't find cs in open */
        gig_dbg(DEBUG_IF, "%s: no cardstate", __func__);
        return;
    }

    gig_dbg(DEBUG_IF, "%u: %s()", cs->minor_index, __func__);

    mutex_lock(&cs->mutex);

    if (!cs->connected)
        gig_dbg(DEBUG_IF, "not connected"); /* nothing to do */
    else if (!cs->port.count)
        dev_warn(cs->dev, "%s: device not opened\n", __func__);
    else if (!--cs->port.count)
        tty_port_tty_set(&cs->port, NULL);

    mutex_unlock(&cs->mutex);

    module_put(cs->driver->owner);
}

static int if_ioctl(struct tty_struct *tty,
            unsigned int cmd, unsigned long arg)
{
    struct cardstate *cs = tty->driver_data;
    int retval = -ENODEV;
    int int_arg;
    unsigned char buf[6];
    unsigned version[4];

    gig_dbg(DEBUG_IF, "%u: %s(0x%x)", cs->minor_index, __func__, cmd);

    if (mutex_lock_interruptible(&cs->mutex))
        return -ERESTARTSYS;

    if (!cs->connected) {
        gig_dbg(DEBUG_IF, "not connected");
        retval = -ENODEV;
    } else {
        retval = 0;
        switch (cmd) {
        case GIGASET_REDIR:
            retval = get_user(int_arg, (int __user *) arg);
            if (retval >= 0)
                retval = if_lock(cs, &int_arg);
            if (retval >= 0)
                retval = put_user(int_arg, (int __user *) arg);
            break;
        case GIGASET_CONFIG:
            retval = get_user(int_arg, (int __user *) arg);
            if (retval >= 0)
                retval = if_config(cs, &int_arg);
            if (retval >= 0)
                retval = put_user(int_arg, (int __user *) arg);
            break;
        case GIGASET_BRKCHARS:
            retval = copy_from_user(&buf,
                        (const unsigned char __user *) arg, 6)
                ? -EFAULT : 0;
            if (retval >= 0) {
                gigaset_dbg_buffer(DEBUG_IF, "GIGASET_BRKCHARS",
                           6, (const unsigned char *) arg);
                retval = cs->ops->brkchars(cs, buf);
            }
            break;
        case GIGASET_VERSION:
            retval = copy_from_user(version,
                        (unsigned __user *) arg, sizeof version)
                ? -EFAULT : 0;
            if (retval >= 0)
                retval = if_version(cs, version);
            if (retval >= 0)
                retval = copy_to_user((unsigned __user *) arg,
                              version, sizeof version)
                    ? -EFAULT : 0;
            break;
        default:
            gig_dbg(DEBUG_IF, "%s: arg not supported - 0x%04x",
                __func__, cmd);
            retval = -ENOIOCTLCMD;
        }
    }

    mutex_unlock(&cs->mutex);

    return retval;
}

static int if_tiocmget(struct tty_struct *tty)
{
    struct cardstate *cs = tty->driver_data;
    int retval;

    gig_dbg(DEBUG_IF, "%u: %s()", cs->minor_index, __func__);

    if (mutex_lock_interruptible(&cs->mutex))
        return -ERESTARTSYS;

    retval = cs->control_state & (TIOCM_RTS | TIOCM_DTR);

    mutex_unlock(&cs->mutex);

    return retval;
}

static int if_tiocmset(struct tty_struct *tty,
               unsigned int set, unsigned int clear)
{
    struct cardstate *cs = tty->driver_data;
    int retval;
    unsigned mc;

    gig_dbg(DEBUG_IF, "%u: %s(0x%x, 0x%x)",
        cs->minor_index, __func__, set, clear);

    if (mutex_lock_interruptible(&cs->mutex))
        return -ERESTARTSYS;

    if (!cs->connected) {
        gig_dbg(DEBUG_IF, "not connected");
        retval = -ENODEV;
    } else {
        mc = (cs->control_state | set) & ~clear & (TIOCM_RTS | TIOCM_DTR);
        retval = cs->ops->set_modem_ctrl(cs, cs->control_state, mc);
        cs->control_state = mc;
    }

    mutex_unlock(&cs->mutex);

    return retval;
}

static int if_write(struct tty_struct *tty, const unsigned char *buf, int count)
{
    struct cardstate *cs = tty->driver_data;
    struct cmdbuf_t *cb;
    int retval;

    gig_dbg(DEBUG_IF, "%u: %s()", cs->minor_index, __func__);

    if (mutex_lock_interruptible(&cs->mutex))
        return -ERESTARTSYS;

    if (!cs->connected) {
        gig_dbg(DEBUG_IF, "not connected");
        retval = -ENODEV;
        goto done;
    }
    if (cs->mstate != MS_LOCKED) {
        dev_warn(cs->dev, "can't write to unlocked device\n");
        retval = -EBUSY;
        goto done;
    }
    if (count <= 0) {
        /* nothing to do */
        retval = 0;
        goto done;
    }

    cb = kmalloc(sizeof(struct cmdbuf_t) + count, GFP_KERNEL);
    if (!cb) {
        dev_err(cs->dev, "%s: out of memory\n", __func__);
        retval = -ENOMEM;
        goto done;
    }

    memcpy(cb->buf, buf, count);
    cb->len = count;
    cb->offset = 0;
    cb->next = NULL;
    cb->wake_tasklet = &cs->if_wake_tasklet;
    retval = cs->ops->write_cmd(cs, cb);
done:
    mutex_unlock(&cs->mutex);
    return retval;
}

static int if_write_room(struct tty_struct *tty)
{
    struct cardstate *cs = tty->driver_data;
    int retval = -ENODEV;

    gig_dbg(DEBUG_IF, "%u: %s()", cs->minor_index, __func__);

    if (mutex_lock_interruptible(&cs->mutex))
        return -ERESTARTSYS;

    if (!cs->connected) {
        gig_dbg(DEBUG_IF, "not connected");
        retval = -ENODEV;
    } else if (cs->mstate != MS_LOCKED) {
        dev_warn(cs->dev, "can't write to unlocked device\n");
        retval = -EBUSY;
    } else
        retval = cs->ops->write_room(cs);

    mutex_unlock(&cs->mutex);

    return retval;
}

static int if_chars_in_buffer(struct tty_struct *tty)
{
    struct cardstate *cs = tty->driver_data;
    int retval = 0;

    gig_dbg(DEBUG_IF, "%u: %s()", cs->minor_index, __func__);

    mutex_lock(&cs->mutex);

    if (!cs->connected)
        gig_dbg(DEBUG_IF, "not connected");
    else if (cs->mstate != MS_LOCKED)
        dev_warn(cs->dev, "can't write to unlocked device\n");
    else
        retval = cs->ops->chars_in_buffer(cs);

    mutex_unlock(&cs->mutex);

    return retval;
}

static void if_throttle(struct tty_struct *tty)
{
    struct cardstate *cs = tty->driver_data;

    gig_dbg(DEBUG_IF, "%u: %s()", cs->minor_index, __func__);

    mutex_lock(&cs->mutex);

    if (!cs->connected)
        gig_dbg(DEBUG_IF, "not connected"); /* nothing to do */
    else
        gig_dbg(DEBUG_IF, "%s: not implemented\n", __func__);

    mutex_unlock(&cs->mutex);
}

static void if_unthrottle(struct tty_struct *tty)
{
    struct cardstate *cs = tty->driver_data;

    gig_dbg(DEBUG_IF, "%u: %s()", cs->minor_index, __func__);

    mutex_lock(&cs->mutex);

    if (!cs->connected)
        gig_dbg(DEBUG_IF, "not connected"); /* nothing to do */
    else
        gig_dbg(DEBUG_IF, "%s: not implemented\n", __func__);

    mutex_unlock(&cs->mutex);
}

static void if_set_termios(struct tty_struct *tty, struct ktermios *old)
{
    struct cardstate *cs = tty->driver_data;
    unsigned int iflag;
    unsigned int cflag;
    unsigned int old_cflag;
    unsigned int control_state, new_state;

    gig_dbg(DEBUG_IF, "%u: %s()", cs->minor_index, __func__);

    mutex_lock(&cs->mutex);

    if (!cs->connected) {
        gig_dbg(DEBUG_IF, "not connected");
        goto out;
    }

    iflag = tty->termios.c_iflag;
    cflag = tty->termios.c_cflag;
    old_cflag = old ? old->c_cflag : cflag;
    gig_dbg(DEBUG_IF, "%u: iflag %x cflag %x old %x",
        cs->minor_index, iflag, cflag, old_cflag);

    /* get a local copy of the current port settings */
    control_state = cs->control_state;

    /*
     * Update baud rate.
     * Do not attempt to cache old rates and skip settings,
     * disconnects screw such tricks up completely.
     * Premature optimization is the root of all evil.
     */

    /* reassert DTR and (maybe) RTS on transition from B0 */
    if ((old_cflag & CBAUD) == B0) {
        new_state = control_state | TIOCM_DTR;
        /* don't set RTS if using hardware flow control */
        if (!(old_cflag & CRTSCTS))
            new_state |= TIOCM_RTS;
        gig_dbg(DEBUG_IF, "%u: from B0 - set DTR%s",
            cs->minor_index,
            (new_state & TIOCM_RTS) ? " only" : "/RTS");
        cs->ops->set_modem_ctrl(cs, control_state, new_state);
        control_state = new_state;
    }

    cs->ops->baud_rate(cs, cflag & CBAUD);

    if ((cflag & CBAUD) == B0) {
        /* Drop RTS and DTR */
        gig_dbg(DEBUG_IF, "%u: to B0 - drop DTR/RTS", cs->minor_index);
        new_state = control_state & ~(TIOCM_DTR | TIOCM_RTS);
        cs->ops->set_modem_ctrl(cs, control_state, new_state);
        control_state = new_state;
    }

    /*
     * Update line control register (LCR)
     */

    cs->ops->set_line_ctrl(cs, cflag);

    /* save off the modified port settings */
    cs->control_state = control_state;

out:
    mutex_unlock(&cs->mutex);
}


/* wakeup tasklet for the write operation */
static void if_wake(unsigned long data)
{
    struct cardstate *cs = (struct cardstate *)data;
    struct tty_struct *tty = tty_port_tty_get(&cs->port);

    if (tty) {
        tty_wakeup(tty);
        tty_kref_put(tty);
    }
}

/*** interface to common ***/

void gigaset_if_init(struct cardstate *cs)
{
    struct gigaset_driver *drv;

    drv = cs->driver;
    if (!drv->have_tty)
        return;

    tasklet_init(&cs->if_wake_tasklet, if_wake, (unsigned long) cs);

    mutex_lock(&cs->mutex);
    cs->tty_dev = tty_port_register_device(&cs->port, drv->tty,
            cs->minor_index, NULL);

    if (!IS_ERR(cs->tty_dev))
        dev_set_drvdata(cs->tty_dev, cs);
    else {
        pr_warning("could not register device to the tty subsystem\n");
        cs->tty_dev = NULL;
    }
    mutex_unlock(&cs->mutex);
}

void gigaset_if_free(struct cardstate *cs)
{
    struct gigaset_driver *drv;

    drv = cs->driver;
    if (!drv->have_tty)
        return;

    tasklet_disable(&cs->if_wake_tasklet);
    tasklet_kill(&cs->if_wake_tasklet);
    cs->tty_dev = NULL;
    tty_unregister_device(drv->tty, cs->minor_index);
}

void gigaset_if_receive(struct cardstate *cs,
            unsigned char *buffer, size_t len)
{
    struct tty_struct *tty = tty_port_tty_get(&cs->port);

    if (tty == NULL) {
        gig_dbg(DEBUG_IF, "receive on closed device");
        return;
    }

    tty_insert_flip_string(tty, buffer, len);
    tty_flip_buffer_push(tty);
    tty_kref_put(tty);
}
EXPORT_SYMBOL_GPL(gigaset_if_receive);

/* gigaset_if_initdriver
 * Initialize tty interface.
 * parameters:
 *  drv     Driver
 *  procname    Name of the driver (e.g. for /proc/tty/drivers)
 *  devname     Name of the device files (prefix without minor number)
 */
void gigaset_if_initdriver(struct gigaset_driver *drv, const char *procname,
               const char *devname)
{
    int ret;
    struct tty_driver *tty;

    drv->have_tty = 0;

    drv->tty = tty = alloc_tty_driver(drv->minors);
    if (tty == NULL)
        goto enomem;

    tty->type =     TTY_DRIVER_TYPE_SERIAL;
    tty->subtype =      SERIAL_TYPE_NORMAL;
    tty->flags =        TTY_DRIVER_REAL_RAW | TTY_DRIVER_DYNAMIC_DEV;

    tty->driver_name =  procname;
    tty->name =     devname;
    tty->minor_start =  drv->minor;

    tty->init_termios          = tty_std_termios;
    tty->init_termios.c_cflag  = B9600 | CS8 | CREAD | HUPCL | CLOCAL;
    tty_set_operations(tty, &if_ops);

    ret = tty_register_driver(tty);
    if (ret < 0) {
        pr_err("error %d registering tty driver\n", ret);
        goto error;
    }
    gig_dbg(DEBUG_IF, "tty driver initialized");
    drv->have_tty = 1;
    return;

enomem:
    pr_err("out of memory\n");
error:
    if (drv->tty)
        put_tty_driver(drv->tty);
}

void gigaset_if_freedriver(struct gigaset_driver *drv)
{
    if (!drv->have_tty)
        return;

    drv->have_tty = 0;
    tty_unregister_driver(drv->tty);
    put_tty_driver(drv->tty);
}