- 根目录:
- drivers
- net
- irda
- irtty-sir.c
/*********************************************************************
*
* 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) {
IRDA_WARNING("%s(), not ready yet!\n", __func__);
return;
}
for (i = 0; i < count; i++) {
/*
* Characters received with a parity error, etc?
*/
if (fp && *fp++) {
IRDA_DEBUG(0, "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;);
IRDA_DEBUG(3, "%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 */
/* First make sure we're not already connected. */
if (tty->disc_data != NULL) {
priv = tty->disc_data;
if (priv && priv->magic == IRTTY_MAGIC) {
ret = -EEXIST;
goto out;
}
tty->disc_data = NULL; /* ### */
}
/* 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);
IRDA_DEBUG(0, "%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);
IRDA_DEBUG(0, "%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)
IRDA_ERROR("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))) {
IRDA_ERROR("%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");