/*
   * interface to user space for the gigaset driver
   *
   * Copyright (c) 2004 by Hansjoerg Lipp <hjlipp@web.de>
   *
   * =====================================================================
   *    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
  ", __func__);
  		return -ENODEV;
  	}
  
  	*arg = 0;
  	return gigaset_enterconfigmode(cs);
  }
  
  /*** the terminal driver ***/
  
  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);
  		cs->port.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
  ", __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
  ");
  		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
  ", __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;
  
  	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
  ");
  		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
  ");
  	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
  ", __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
  ", __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);
  }
  
  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,
  };
  
  
  /* wakeup tasklet for the write operation */
  static void if_wake(unsigned long data)
  {
  	struct cardstate *cs = (struct cardstate *)data;
  
  	tty_port_tty_wakeup(&cs->port);
  }
  
  /*** 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
  ");
  		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);
  }
  
  /**
   * gigaset_if_receive() - pass a received block of data to the tty device
   * @cs:		device descriptor structure.
   * @buffer:	received data.
   * @len:	number of bytes received.
   *
   * Called by asyncdata/isocdata if a block of data received from the
   * device must be sent to userspace through the ttyG* device.
   */
  void gigaset_if_receive(struct cardstate *cs,
  			unsigned char *buffer, size_t len)
  {
  	tty_insert_flip_string(&cs->port, buffer, len);
  	tty_flip_buffer_push(&cs->port);
  }
  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
  ", ret);
  		goto error;
  	}
  	gig_dbg(DEBUG_IF, "tty driver initialized");
  	drv->have_tty = 1;
  	return;
  
  enomem:
  	pr_err("out of memory
  ");
  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);
  }