interface.c

linux 内核源代码

	if (!cs->open_count)
		warn("%s: device not opened", __func__);
	else if (atomic_read(&cs->mstate) != MS_LOCKED) {
		warn("can't write to unlocked device");
		retval = -EBUSY;
	} else if (!cs->connected) {
		gig_dbg(DEBUG_ANY, "can't write to unplugged device");
		retval = -EBUSY; //FIXME
	} else {
		retval = cs->ops->write_cmd(cs, buf, count,
					    &cs->if_wake_tasklet);
	}

	mutex_unlock(&cs->mutex);

	return retval;
}

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

	cs = (struct cardstate *) tty->driver_data;
	if (!cs) {
		err("cs==NULL in %s", __func__);
		return -ENODEV;
	}

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

	if (mutex_lock_interruptible(&cs->mutex))
		return -ERESTARTSYS; // FIXME -EINTR?

	if (!cs->open_count)
		warn("%s: device not opened", __func__);
	else if (atomic_read(&cs->mstate) != MS_LOCKED) {
		warn("can't write to unlocked device");
		retval = -EBUSY; //FIXME
	} else if (!cs->connected) {
		gig_dbg(DEBUG_ANY, "can't write to unplugged device");
		retval = -EBUSY; //FIXME
	} 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;
	int retval = -ENODEV;

	cs = (struct cardstate *) tty->driver_data;
	if (!cs) {
		err("cs==NULL in %s", __func__);
		return -ENODEV;
	}

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

	if (mutex_lock_interruptible(&cs->mutex))
		return -ERESTARTSYS; // FIXME -EINTR?

	if (!cs->open_count)
		warn("%s: device not opened", __func__);
	else if (atomic_read(&cs->mstate) != MS_LOCKED) {
		warn("can't write to unlocked device");
		retval = -EBUSY;
	} else if (!cs->connected) {
		gig_dbg(DEBUG_ANY, "can't write to unplugged device");
		retval = -EBUSY; //FIXME
	} 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;

	cs = (struct cardstate *) tty->driver_data;
	if (!cs) {
		err("cs==NULL in %s", __func__);
		return;
	}

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

	mutex_lock(&cs->mutex);

	if (!cs->open_count)
		warn("%s: device not opened", __func__);
	else {
		//FIXME
	}

	mutex_unlock(&cs->mutex);
}

static void if_unthrottle(struct tty_struct *tty)
{
	struct cardstate *cs;

	cs = (struct cardstate *) tty->driver_data;
	if (!cs) {
		err("cs==NULL in %s", __func__);
		return;
	}

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

	mutex_lock(&cs->mutex);

	if (!cs->open_count)
		warn("%s: device not opened", __func__);
	else {
		//FIXME
	}

	mutex_unlock(&cs->mutex);
}

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

	cs = (struct cardstate *) tty->driver_data;
	if (!cs) {
		err("cs==NULL in %s", __func__);
		return;
	}

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

	mutex_lock(&cs->mutex);

	if (!cs->open_count) {
		warn("%s: device not opened", __func__);
		goto out;
	}

	if (!cs->connected) {
		gig_dbg(DEBUG_ANY, "can't communicate with unplugged device");
		goto out;
	}

	// stolen from mct_u232.c
	iflag = tty->termios->c_iflag;
	cflag = tty->termios->c_cflag;
	old_cflag = old ? old->c_cflag : cflag; //FIXME?
	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);

#if 0
	//FIXME this hangs M101 [ts 2005-03-09]
	//FIXME do we need this?
	/*
	 * Set flow control: well, I do not really now how to handle DTR/RTS.
	 * Just do what we have seen with SniffUSB on Win98.
	 */
	/* Drop DTR/RTS if no flow control otherwise assert */
	gig_dbg(DEBUG_IF, "%u: control_state %x",
		cs->minor_index, control_state);
	new_state = control_state;
	if ((iflag & IXOFF) || (iflag & IXON) || (cflag & CRTSCTS))
		new_state |= TIOCM_DTR | TIOCM_RTS;
	else
		new_state &= ~(TIOCM_DTR | TIOCM_RTS);
	if (new_state != control_state) {
		gig_dbg(DEBUG_IF, "%u: new_state %x",
			cs->minor_index, new_state);
		gigaset_set_modem_ctrl(cs, control_state, new_state);
		control_state = new_state;
	}
#endif

	/* 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;

	if (cs->tty)
		tty_wakeup(cs->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_register_device(drv->tty, cs->minor_index, NULL);

	if (!IS_ERR(cs->tty_dev))
		dev_set_drvdata(cs->tty_dev, cs);
	else {
		warn("could not register device to the tty subsystem");
		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)
{
	unsigned long flags;
	struct tty_struct *tty;

	spin_lock_irqsave(&cs->lock, flags);
	if ((tty = cs->tty) == NULL)
		gig_dbg(DEBUG_ANY, "receive on closed device");
	else {
		tty_buffer_request_room(tty, len);
		tty_insert_flip_string(tty, buffer, len);
		tty_flip_buffer_push(tty);
	}
	spin_unlock_irqrestore(&cs->lock, flags);
}
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)
{
	unsigned minors = drv->minors;
	int ret;
	struct tty_driver *tty;

	drv->have_tty = 0;

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

	tty->magic =		TTY_DRIVER_MAGIC,
	tty->major =		GIG_MAJOR,
	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->num =		drv->minors;

	tty->owner =		THIS_MODULE;

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

	ret = tty_register_driver(tty);
	if (ret < 0) {
		warn("failed to register tty driver (error %d)", ret);
		goto error;
	}
	gig_dbg(DEBUG_IF, "tty driver initialized");
	drv->have_tty = 1;
	return;

enomem:
	warn("could not allocate tty structures");
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);
}