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- /*********************************************************************
- *
- * Filename: irtty-sir.c
- * Version: 2.0
- * Description: IrDA line discipline implementation
- * Status: Experimental.
- * Author: Dag Brattli <dagb@cs.uit.no>
- * Created at: Tue Dec 9 21:18:38 1997
- * Modified at: Sun Oct 27 22:13:30 2002
- * Modified by: Martin Diehl <mad@mdiehl.de>
- * Sources: slip.c by Laurence Culhane, <loz@holmes.demon.co.uk>
- * Fred N. van Kempen, <waltje@uwalt.nl.mugnet.org>
- *
- * Copyright (c) 1998-2000 Dag Brattli,
- * Copyright (c) 2002 Martin Diehl,
- * All Rights Reserved.
- *
- * 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.
- *
- * Neither Dag Brattli nor University of Tromsø admit liability nor
- * provide warranty for any of this software. This material is
- * provided "AS-IS" and at no charge.
- *
- ********************************************************************/
- #include <linux/module.h>
- #include <linux/kernel.h>
- #include <linux/slab.h>
- #include <linux/tty.h>
- #include <linux/init.h>
- #include <asm/uaccess.h>
- #include <linux/delay.h>
- #include <linux/mutex.h>
- #include <net/irda/irda.h>
- #include <net/irda/irda_device.h>
- #include "sir-dev.h"
- #include "irtty-sir.h"
- static int qos_mtt_bits = 0x03; /* 5 ms or more */
- module_param(qos_mtt_bits, int, 0);
- MODULE_PARM_DESC(qos_mtt_bits, "Minimum Turn Time");
- /* ------------------------------------------------------- */
- /* device configuration callbacks always invoked with irda-thread context */
- /* find out, how many chars we have in buffers below us
- * this is allowed to lie, i.e. return less chars than we
- * actually have. The returned value is used to determine
- * how long the irdathread should wait before doing the
- * real blocking wait_until_sent()
- */
- static int irtty_chars_in_buffer(struct sir_dev *dev)
- {
- struct sirtty_cb *priv = dev->priv;
- IRDA_ASSERT(priv != NULL, return -1;);
- IRDA_ASSERT(priv->magic == IRTTY_MAGIC, return -1;);
- return tty_chars_in_buffer(priv->tty);
- }
- /* Wait (sleep) until underlaying hardware finished transmission
- * i.e. hardware buffers are drained
- * this must block and not return before all characters are really sent
- *
- * If the tty sits on top of a 16550A-like uart, there are typically
- * up to 16 bytes in the fifo - f.e. 9600 bps 8N1 needs 16.7 msec
- *
- * With usbserial the uart-fifo is basically replaced by the converter's
- * outgoing endpoint buffer, which can usually hold 64 bytes (at least).
- * With pl2303 it appears we are safe with 60msec here.
- *
- * I really wish all serial drivers would provide
- * correct implementation of wait_until_sent()
- */
- #define USBSERIAL_TX_DONE_DELAY 60
- static void irtty_wait_until_sent(struct sir_dev *dev)
- {
- struct sirtty_cb *priv = dev->priv;
- struct tty_struct *tty;
- IRDA_ASSERT(priv != NULL, return;);
- IRDA_ASSERT(priv->magic == IRTTY_MAGIC, return;);
- tty = priv->tty;
- if (tty->ops->wait_until_sent) {
- tty->ops->wait_until_sent(tty, msecs_to_jiffies(100));
- }
- else {
- msleep(USBSERIAL_TX_DONE_DELAY);
- }
- }
- /*
- * Function irtty_change_speed (dev, speed)
- *
- * Change the speed of the serial port.
- *
- * This may sleep in set_termios (usbserial driver f.e.) and must
- * not be called from interrupt/timer/tasklet therefore.
- * All such invocations are deferred to kIrDAd now so we can sleep there.
- */
- static int irtty_change_speed(struct sir_dev *dev, unsigned speed)
- {
- struct sirtty_cb *priv = dev->priv;
- struct tty_struct *tty;
- struct ktermios old_termios;
- int cflag;
- IRDA_ASSERT(priv != NULL, return -1;);
- IRDA_ASSERT(priv->magic == IRTTY_MAGIC, return -1;);
- tty = priv->tty;
- down_write(&tty->termios_rwsem);
- old_termios = tty->termios;
- cflag = tty->termios.c_cflag;
- tty_encode_baud_rate(tty, speed, speed);
- if (tty->ops->set_termios)
- tty->ops->set_termios(tty, &old_termios);
- priv->io.speed = speed;
- up_write(&tty->termios_rwsem);
- return 0;
- }
- /*
- * Function irtty_set_dtr_rts (dev, dtr, rts)
- *
- * This function can be used by dongles etc. to set or reset the status
- * of the dtr and rts lines
- */
- static int irtty_set_dtr_rts(struct sir_dev *dev, int dtr, int rts)
- {
- struct sirtty_cb *priv = dev->priv;
- int set = 0;
- int clear = 0;
- IRDA_ASSERT(priv != NULL, return -1;);
- IRDA_ASSERT(priv->magic == IRTTY_MAGIC, return -1;);
- if (rts)
- set |= TIOCM_RTS;
- else
- clear |= TIOCM_RTS;
- if (dtr)
- set |= TIOCM_DTR;
- else
- clear |= TIOCM_DTR;
- /*
- * We can't use ioctl() because it expects a non-null file structure,
- * and we don't have that here.
- * This function is not yet defined for all tty driver, so
- * let's be careful... Jean II
- */
- IRDA_ASSERT(priv->tty->ops->tiocmset != NULL, return -1;);
- priv->tty->ops->tiocmset(priv->tty, set, clear);
- return 0;
- }
- /* ------------------------------------------------------- */
- /* called from sir_dev when there is more data to send
- * context is either netdev->hard_xmit or some transmit-completion bh
- * i.e. we are under spinlock here and must not sleep.
- */
- static int irtty_do_write(struct sir_dev *dev, const unsigned char *ptr, size_t len)
- {
- struct sirtty_cb *priv = dev->priv;
- struct tty_struct *tty;
- int writelen;
- IRDA_ASSERT(priv != NULL, return -1;);
- IRDA_ASSERT(priv->magic == IRTTY_MAGIC, return -1;);
- tty = priv->tty;
- if (!tty->ops->write)
- return 0;
- set_bit(TTY_DO_WRITE_WAKEUP, &tty->flags);
- writelen = tty_write_room(tty);
- if (writelen > len)
- writelen = len;
- return tty->ops->write(tty, ptr, writelen);
- }
- /* ------------------------------------------------------- */
- /* irda line discipline callbacks */
- /*
- * Function irtty_receive_buf( tty, cp, count)
- *
- * Handle the 'receiver data ready' interrupt. This function is called
- * by the 'tty_io' module in the kernel when a block of IrDA data has
- * been received, which can now be decapsulated and delivered for
- * further processing
- *
- * calling context depends on underlying driver and tty->port->low_latency!
- * for example (low_latency: 1 / 0):
- * serial.c: uart-interrupt / softint
- * usbserial: urb-complete-interrupt / softint
- */
- static void irtty_receive_buf(struct tty_struct *tty, const unsigned char *cp,
- char *fp, int count)
- {
- struct sir_dev *dev;
- struct sirtty_cb *priv = tty->disc_data;
- int i;
- IRDA_ASSERT(priv != NULL, return;);
- IRDA_ASSERT(priv->magic == IRTTY_MAGIC, return;);
- if (unlikely(count==0)) /* yes, this happens */
- return;
- dev = priv->dev;
- if (!dev) {
- net_warn_ratelimited("%s(), not ready yet!\n", __func__);
- return;
- }
- for (i = 0; i < count; i++) {
- /*
- * Characters received with a parity error, etc?
- */
- if (fp && *fp++) {
- pr_debug("Framing or parity error!\n");
- sirdev_receive(dev, NULL, 0); /* notify sir_dev (updating stats) */
- return;
- }
- }
- sirdev_receive(dev, cp, count);
- }
- /*
- * Function irtty_write_wakeup (tty)
- *
- * Called by the driver when there's room for more data. If we have
- * more packets to send, we send them here.
- *
- */
- static void irtty_write_wakeup(struct tty_struct *tty)
- {
- struct sirtty_cb *priv = tty->disc_data;
- IRDA_ASSERT(priv != NULL, return;);
- IRDA_ASSERT(priv->magic == IRTTY_MAGIC, return;);
- clear_bit(TTY_DO_WRITE_WAKEUP, &tty->flags);
- if (priv->dev)
- sirdev_write_complete(priv->dev);
- }
- /* ------------------------------------------------------- */
- /*
- * Function irtty_stop_receiver (tty, stop)
- *
- */
- static inline void irtty_stop_receiver(struct tty_struct *tty, int stop)
- {
- struct ktermios old_termios;
- int cflag;
- down_write(&tty->termios_rwsem);
- old_termios = tty->termios;
- cflag = tty->termios.c_cflag;
-
- if (stop)
- cflag &= ~CREAD;
- else
- cflag |= CREAD;
- tty->termios.c_cflag = cflag;
- if (tty->ops->set_termios)
- tty->ops->set_termios(tty, &old_termios);
- up_write(&tty->termios_rwsem);
- }
- /*****************************************************************/
- /* serialize ldisc open/close with sir_dev */
- static DEFINE_MUTEX(irtty_mutex);
- /* notifier from sir_dev when irda% device gets opened (ifup) */
- static int irtty_start_dev(struct sir_dev *dev)
- {
- struct sirtty_cb *priv;
- struct tty_struct *tty;
- /* serialize with ldisc open/close */
- mutex_lock(&irtty_mutex);
- priv = dev->priv;
- if (unlikely(!priv || priv->magic!=IRTTY_MAGIC)) {
- mutex_unlock(&irtty_mutex);
- return -ESTALE;
- }
- tty = priv->tty;
- if (tty->ops->start)
- tty->ops->start(tty);
- /* Make sure we can receive more data */
- irtty_stop_receiver(tty, FALSE);
- mutex_unlock(&irtty_mutex);
- return 0;
- }
- /* notifier from sir_dev when irda% device gets closed (ifdown) */
- static int irtty_stop_dev(struct sir_dev *dev)
- {
- struct sirtty_cb *priv;
- struct tty_struct *tty;
- /* serialize with ldisc open/close */
- mutex_lock(&irtty_mutex);
- priv = dev->priv;
- if (unlikely(!priv || priv->magic!=IRTTY_MAGIC)) {
- mutex_unlock(&irtty_mutex);
- return -ESTALE;
- }
- tty = priv->tty;
- /* Make sure we don't receive more data */
- irtty_stop_receiver(tty, TRUE);
- if (tty->ops->stop)
- tty->ops->stop(tty);
- mutex_unlock(&irtty_mutex);
- return 0;
- }
- /* ------------------------------------------------------- */
- static struct sir_driver sir_tty_drv = {
- .owner = THIS_MODULE,
- .driver_name = "sir_tty",
- .start_dev = irtty_start_dev,
- .stop_dev = irtty_stop_dev,
- .do_write = irtty_do_write,
- .chars_in_buffer = irtty_chars_in_buffer,
- .wait_until_sent = irtty_wait_until_sent,
- .set_speed = irtty_change_speed,
- .set_dtr_rts = irtty_set_dtr_rts,
- };
- /* ------------------------------------------------------- */
- /*
- * Function irtty_ioctl (tty, file, cmd, arg)
- *
- * The Swiss army knife of system calls :-)
- *
- */
- static int irtty_ioctl(struct tty_struct *tty, struct file *file, unsigned int cmd, unsigned long arg)
- {
- struct irtty_info { char name[6]; } info;
- struct sir_dev *dev;
- struct sirtty_cb *priv = tty->disc_data;
- int err = 0;
- IRDA_ASSERT(priv != NULL, return -ENODEV;);
- IRDA_ASSERT(priv->magic == IRTTY_MAGIC, return -EBADR;);
- pr_debug("%s(cmd=0x%X)\n", __func__, cmd);
- dev = priv->dev;
- IRDA_ASSERT(dev != NULL, return -1;);
- switch (cmd) {
- case IRTTY_IOCTDONGLE:
- /* this call blocks for completion */
- err = sirdev_set_dongle(dev, (IRDA_DONGLE) arg);
- break;
- case IRTTY_IOCGET:
- IRDA_ASSERT(dev->netdev != NULL, return -1;);
- memset(&info, 0, sizeof(info));
- strncpy(info.name, dev->netdev->name, sizeof(info.name)-1);
- if (copy_to_user((void __user *)arg, &info, sizeof(info)))
- err = -EFAULT;
- break;
- default:
- err = tty_mode_ioctl(tty, file, cmd, arg);
- break;
- }
- return err;
- }
- /*
- * Function irtty_open(tty)
- *
- * This function is called by the TTY module when the IrDA line
- * discipline is called for. Because we are sure the tty line exists,
- * we only have to link it to a free IrDA channel.
- */
- static int irtty_open(struct tty_struct *tty)
- {
- struct sir_dev *dev;
- struct sirtty_cb *priv;
- int ret = 0;
- /* Module stuff handled via irda_ldisc.owner - Jean II */
- /* stop the underlying driver */
- irtty_stop_receiver(tty, TRUE);
- if (tty->ops->stop)
- tty->ops->stop(tty);
- tty_driver_flush_buffer(tty);
-
- /* apply mtt override */
- sir_tty_drv.qos_mtt_bits = qos_mtt_bits;
- /* get a sir device instance for this driver */
- dev = sirdev_get_instance(&sir_tty_drv, tty->name);
- if (!dev) {
- ret = -ENODEV;
- goto out;
- }
- /* allocate private device info block */
- priv = kzalloc(sizeof(*priv), GFP_KERNEL);
- if (!priv) {
- ret = -ENOMEM;
- goto out_put;
- }
- priv->magic = IRTTY_MAGIC;
- priv->tty = tty;
- priv->dev = dev;
- /* serialize with start_dev - in case we were racing with ifup */
- mutex_lock(&irtty_mutex);
- dev->priv = priv;
- tty->disc_data = priv;
- tty->receive_room = 65536;
- mutex_unlock(&irtty_mutex);
- pr_debug("%s - %s: irda line discipline opened\n", __func__, tty->name);
- return 0;
- out_put:
- sirdev_put_instance(dev);
- out:
- return ret;
- }
- /*
- * Function irtty_close (tty)
- *
- * Close down a IrDA channel. This means flushing out any pending queues,
- * and then restoring the TTY line discipline to what it was before it got
- * hooked to IrDA (which usually is TTY again).
- */
- static void irtty_close(struct tty_struct *tty)
- {
- struct sirtty_cb *priv = tty->disc_data;
- IRDA_ASSERT(priv != NULL, return;);
- IRDA_ASSERT(priv->magic == IRTTY_MAGIC, return;);
- /* Hm, with a dongle attached the dongle driver wants
- * to close the dongle - which requires the use of
- * some tty write and/or termios or ioctl operations.
- * Are we allowed to call those when already requested
- * to shutdown the ldisc?
- * If not, we should somehow mark the dev being staled.
- * Question remains, how to close the dongle in this case...
- * For now let's assume we are granted to issue tty driver calls
- * until we return here from the ldisc close. I'm just wondering
- * how this behaves with hotpluggable serial hardware like
- * rs232-pcmcia card or usb-serial...
- *
- * priv->tty = NULL?;
- */
- /* we are dead now */
- tty->disc_data = NULL;
- sirdev_put_instance(priv->dev);
- /* Stop tty */
- clear_bit(TTY_DO_WRITE_WAKEUP, &tty->flags);
- if (tty->ops->stop)
- tty->ops->stop(tty);
- kfree(priv);
- pr_debug("%s - %s: irda line discipline closed\n", __func__, tty->name);
- }
- /* ------------------------------------------------------- */
- static struct tty_ldisc_ops irda_ldisc = {
- .magic = TTY_LDISC_MAGIC,
- .name = "irda",
- .flags = 0,
- .open = irtty_open,
- .close = irtty_close,
- .read = NULL,
- .write = NULL,
- .ioctl = irtty_ioctl,
- .poll = NULL,
- .receive_buf = irtty_receive_buf,
- .write_wakeup = irtty_write_wakeup,
- .owner = THIS_MODULE,
- };
- /* ------------------------------------------------------- */
- static int __init irtty_sir_init(void)
- {
- int err;
- if ((err = tty_register_ldisc(N_IRDA, &irda_ldisc)) != 0)
- net_err_ratelimited("IrDA: can't register line discipline (err = %d)\n",
- err);
- return err;
- }
- static void __exit irtty_sir_cleanup(void)
- {
- int err;
- if ((err = tty_unregister_ldisc(N_IRDA))) {
- net_err_ratelimited("%s(), can't unregister line discipline (err = %d)\n",
- __func__, err);
- }
- }
- module_init(irtty_sir_init);
- module_exit(irtty_sir_cleanup);
- MODULE_AUTHOR("Dag Brattli <dagb@cs.uit.no>");
- MODULE_DESCRIPTION("IrDA TTY device driver");
- MODULE_ALIAS_LDISC(N_IRDA);
- MODULE_LICENSE("GPL");
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