--- /dev/null
+/*********************************************************************
+ *
+ * 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 */
+
+ /* 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);
+
+ 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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