- Linus: drop support for old-style Makefiles entirely. Big.

[davej-history.git] / net / irda / ircomm / ircomm_tty.c

/*********************************************************************
 *                
 * Filename:      ircomm_tty.c
 * Version:       1.0
 * Description:   IrCOMM serial TTY driver
 * Status:        Experimental.
 * Author:        Dag Brattli <dagb@cs.uit.no>
 * Created at:    Sun Jun  6 21:00:56 1999
 * Modified at:   Wed Feb 23 00:09:02 2000
 * Modified by:   Dag Brattli <dagb@cs.uit.no>
 * Sources:       serial.c and previous IrCOMM work by Takahide Higuchi
 * 
 *     Copyright (c) 1999-2000 Dag Brattli, 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.
 * 
 *     This program is distributed in the hope that it will be useful,
 *     but WITHOUT ANY WARRANTY; without even the implied warranty of
 *     MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
 *     GNU General Public License for more details.
 * 
 *     You should have received a copy of the GNU General Public License 
 *     along with this program; if not, write to the Free Software 
 *     Foundation, Inc., 59 Temple Place, Suite 330, Boston, 
 *     MA 02111-1307 USA
 *     
 ********************************************************************/

#include <linux/config.h>
#include <linux/init.h>
#include <linux/module.h>
#include <linux/fs.h>
#include <linux/sched.h>
#include <linux/termios.h>
#include <linux/tty.h>
#include <linux/interrupt.h>

#include <asm/segment.h>
#include <asm/uaccess.h>

#include <net/irda/irda.h>
#include <net/irda/irmod.h>

#include <net/irda/ircomm_core.h>
#include <net/irda/ircomm_param.h>
#include <net/irda/ircomm_tty_attach.h>
#include <net/irda/ircomm_tty.h>

static int  ircomm_tty_open(struct tty_struct *tty, struct file *filp);
static void ircomm_tty_close(struct tty_struct * tty, struct file *filp);
static int  ircomm_tty_write(struct tty_struct * tty, int from_user,
                             const unsigned char *buf, int count);
static int  ircomm_tty_write_room(struct tty_struct *tty);
static void ircomm_tty_throttle(struct tty_struct *tty);
static void ircomm_tty_unthrottle(struct tty_struct *tty);
static int  ircomm_tty_chars_in_buffer(struct tty_struct *tty);
static void ircomm_tty_flush_buffer(struct tty_struct *tty);
static void ircomm_tty_send_xchar(struct tty_struct *tty, char ch);
static void ircomm_tty_wait_until_sent(struct tty_struct *tty, int timeout);
static void ircomm_tty_hangup(struct tty_struct *tty);
static void ircomm_tty_do_softint(void *private_);
static void ircomm_tty_shutdown(struct ircomm_tty_cb *self);

static int ircomm_tty_data_indication(void *instance, void *sap,
                                      struct sk_buff *skb);
static int ircomm_tty_control_indication(void *instance, void *sap,
                                         struct sk_buff *skb);
static void ircomm_tty_flow_indication(void *instance, void *sap, 
                                       LOCAL_FLOW cmd);
#ifdef CONFIG_PROC_FS
static int ircomm_tty_read_proc(char *buf, char **start, off_t offset, int len,
                                int *eof, void *unused);
#endif /* CONFIG_PROC_FS */
static struct tty_driver driver;
static int ircomm_tty_refcount;       /* If we manage several devices */

static struct tty_struct *ircomm_tty_table[NR_PTYS];
static struct termios *ircomm_tty_termios[NR_PTYS];
static struct termios *ircomm_tty_termios_locked[NR_PTYS];

hashbin_t *ircomm_tty = NULL;

/*
 * Function ircomm_tty_init()
 *
 *    Init IrCOMM TTY layer/driver
 *
 */
int __init ircomm_tty_init(void)
{       
        ircomm_tty = hashbin_new(HB_LOCAL); 
        if (ircomm_tty == NULL) {
                ERROR(__FUNCTION__ "(), can't allocate hashbin!\n");
                return -ENOMEM;
        }

        memset(&driver, 0, sizeof(struct tty_driver));
        driver.magic           = TTY_DRIVER_MAGIC;
        driver.driver_name     = "ircomm";
#ifdef CONFIG_DEVFS_FS
        driver.name            = "ircomm%d";
#else
        driver.name            = "ircomm";
#endif
        driver.major           = IRCOMM_TTY_MAJOR;
        driver.minor_start     = IRCOMM_TTY_MINOR;
        driver.num             = IRCOMM_TTY_PORTS;
        driver.type            = TTY_DRIVER_TYPE_SERIAL;
        driver.subtype         = SERIAL_TYPE_NORMAL;
        driver.init_termios    = tty_std_termios;
        driver.init_termios.c_cflag = B9600 | CS8 | CREAD | HUPCL | CLOCAL;
        driver.flags           = TTY_DRIVER_REAL_RAW;
        driver.refcount        = &ircomm_tty_refcount;
        driver.table           = ircomm_tty_table;
        driver.termios         = ircomm_tty_termios;
        driver.termios_locked  = ircomm_tty_termios_locked;
        driver.open            = ircomm_tty_open;
        driver.close           = ircomm_tty_close;
        driver.write           = ircomm_tty_write;
        driver.write_room      = ircomm_tty_write_room;
        driver.chars_in_buffer = ircomm_tty_chars_in_buffer;
        driver.flush_buffer    = ircomm_tty_flush_buffer;
        driver.ioctl           = ircomm_tty_ioctl;
        driver.throttle        = ircomm_tty_throttle;
        driver.unthrottle      = ircomm_tty_unthrottle;
        driver.send_xchar      = ircomm_tty_send_xchar;
        driver.set_termios     = ircomm_tty_set_termios;
        driver.stop            = ircomm_tty_stop;
        driver.start           = ircomm_tty_start;
        driver.hangup          = ircomm_tty_hangup;
        driver.wait_until_sent = ircomm_tty_wait_until_sent;
#ifdef CONFIG_PROC_FS
        driver.read_proc       = ircomm_tty_read_proc;
#endif /* CONFIG_PROC_FS */
        if (tty_register_driver(&driver)) {
                ERROR(__FUNCTION__ "Couldn't register serial driver\n");
                return -1;
        }
        return 0;
}

#ifdef MODULE
static void __ircomm_tty_cleanup(struct ircomm_tty_cb *self)
{
        IRDA_DEBUG(0, __FUNCTION__ "()\n");

        ASSERT(self != NULL, return;);
        ASSERT(self->magic == IRCOMM_TTY_MAGIC, return;);

        ircomm_tty_shutdown(self);

        self->magic = 0;
        kfree(self);
}

/*
 * Function ircomm_tty_cleanup ()
 *
 *    Remove IrCOMM TTY layer/driver
 *
 */
void ircomm_tty_cleanup(void)
{
        int ret;

        IRDA_DEBUG(4, __FUNCTION__"()\n");      

        ret = tty_unregister_driver(&driver);
        if (ret) {
                ERROR(__FUNCTION__ "(), failed to unregister driver\n");
                return;
        }

        hashbin_delete(ircomm_tty, (FREE_FUNC) __ircomm_tty_cleanup);
}
#endif /* MODULE */

/*
 * Function ircomm_startup (self)
 *
 *    
 *
 */
static int ircomm_tty_startup(struct ircomm_tty_cb *self)
{
        notify_t notify;
        int ret;

        IRDA_DEBUG(2, __FUNCTION__ "()\n");

        ASSERT(self != NULL, return -1;);
        ASSERT(self->magic == IRCOMM_TTY_MAGIC, return -1;);

        /* Already open */
        if (self->flags & ASYNC_INITIALIZED) {
                IRDA_DEBUG(2, __FUNCTION__ "(), already open so break out!\n");
                return 0;
        }

        /* Register with IrCOMM */
        irda_notify_init(&notify);
        /* These callbacks we must handle ourselves */
        notify.data_indication       = ircomm_tty_data_indication;
        notify.udata_indication      = ircomm_tty_control_indication;
        notify.flow_indication       = ircomm_tty_flow_indication;

        /* Use the ircomm_tty interface for these ones */
        notify.disconnect_indication = ircomm_tty_disconnect_indication;
        notify.connect_confirm       = ircomm_tty_connect_confirm;
        notify.connect_indication    = ircomm_tty_connect_indication;
        strncpy(notify.name, "ircomm_tty", NOTIFY_MAX_NAME);
        notify.instance = self;

        if (!self->ircomm) {
                self->ircomm = ircomm_open(&notify, self->service_type, 
                                           self->line);
        }
        if (!self->ircomm)
                return -ENODEV;

        self->slsap_sel = self->ircomm->slsap_sel;

        /* Connect IrCOMM link with remote device */
        ret = ircomm_tty_attach_cable(self);
        if (ret < 0) {
                ERROR(__FUNCTION__ "(), error attaching cable!\n");
                return ret;
        }

        self->flags |= ASYNC_INITIALIZED;

        return 0;
}

/*
 * Function ircomm_block_til_ready (self, filp)
 *
 *    
 *
 */
static int ircomm_tty_block_til_ready(struct ircomm_tty_cb *self, 
                                      struct file *filp)
{
        DECLARE_WAITQUEUE(wait, current);
        int             retval;
        int             do_clocal = 0, extra_count = 0;
        unsigned long   flags;
        struct tty_struct *tty;
        
        IRDA_DEBUG(2, __FUNCTION__ "()\n");

        tty = self->tty;

        if (tty->driver.subtype == SERIAL_TYPE_CALLOUT) {
                /* this is a callout device */
                /* just verify that normal device is not in use */
                if (self->flags & ASYNC_NORMAL_ACTIVE)
                        return -EBUSY;
                if ((self->flags & ASYNC_CALLOUT_ACTIVE) &&
                    (self->flags & ASYNC_SESSION_LOCKOUT) &&
                    (self->session != current->session))
                        return -EBUSY;
                if ((self->flags & ASYNC_CALLOUT_ACTIVE) &&
                    (self->flags & ASYNC_PGRP_LOCKOUT) &&
                    (self->pgrp != current->pgrp))
                        return -EBUSY;
                self->flags |= ASYNC_CALLOUT_ACTIVE;
                return 0;
        }
        
        /*
         * If non-blocking mode is set, or the port is not enabled,
         * then make the check up front and then exit.
         */     
        if (filp->f_flags & O_NONBLOCK || tty->flags & (1 << TTY_IO_ERROR)){
                /* nonblock mode is set or port is not enabled */
                /* just verify that callout device is not active */
                if (self->flags & ASYNC_CALLOUT_ACTIVE)
                        return -EBUSY;
                self->flags |= ASYNC_NORMAL_ACTIVE;

                IRDA_DEBUG(1, __FUNCTION__ "(), O_NONBLOCK requested!\n");
                return 0;
        }

        if (self->flags & ASYNC_CALLOUT_ACTIVE) {
                if (self->normal_termios.c_cflag & CLOCAL) {
                        IRDA_DEBUG(1, __FUNCTION__ "(), doing CLOCAL!\n");
                        do_clocal = 1;
                }
        } else {
                if (tty->termios->c_cflag & CLOCAL) {
                        IRDA_DEBUG(1, __FUNCTION__ "(), doing CLOCAL!\n");
                        do_clocal = 1;
                }
        }
        
        /* Wait for carrier detect and the line to become
         * free (i.e., not in use by the callout).  While we are in
         * this loop, self->open_count is dropped by one, so that
         * mgsl_close() knows when to free things.  We restore it upon
         * exit, either normal or abnormal.
         */
         
        retval = 0;
        add_wait_queue(&self->open_wait, &wait);
        
        IRDA_DEBUG(2, "%s(%d):block_til_ready before block on %s open_count=%d\n",
              __FILE__,__LINE__, tty->driver.name, self->open_count );

        save_flags(flags); cli();
        if (!tty_hung_up_p(filp)) {
                extra_count = 1;
                self->open_count--;
        }
        restore_flags(flags);
        self->blocked_open++;
        
        while (1) {
                if (!(self->flags & ASYNC_CALLOUT_ACTIVE) &&
                    (tty->termios->c_cflag & CBAUD)) {
                        save_flags(flags); cli();
                        self->settings.dte |= IRCOMM_RTS + IRCOMM_DTR;
                        
                        ircomm_param_request(self, IRCOMM_DTE, TRUE);
                        restore_flags(flags);
                }
                
                current->state = TASK_INTERRUPTIBLE;
                
                if (tty_hung_up_p(filp) || !(self->flags & ASYNC_INITIALIZED)){
                        retval = (self->flags & ASYNC_HUP_NOTIFY) ?
                                        -EAGAIN : -ERESTARTSYS;
                        break;
                }
                
                /*  
                 * Check if link is ready now. Even if CLOCAL is
                 * specified, we cannot return before the IrCOMM link is
                 * ready 
                 */
                if (!(self->flags & ASYNC_CALLOUT_ACTIVE) &&
                    !(self->flags & ASYNC_CLOSING) &&
                    (do_clocal || (self->settings.dce & IRCOMM_CD)) &&
                    self->state == IRCOMM_TTY_READY)
                {
                        break;
                }
                        
                if (signal_pending(current)) {
                        retval = -ERESTARTSYS;
                        break;
                }
                
                IRDA_DEBUG(1, "%s(%d):block_til_ready blocking on %s open_count=%d\n",
                      __FILE__,__LINE__, tty->driver.name, self->open_count );
                
                schedule();
        }
        
        __set_current_state(TASK_RUNNING);
        remove_wait_queue(&self->open_wait, &wait);
        
        if (extra_count)
                self->open_count++;
        self->blocked_open--;
        
        IRDA_DEBUG(1, "%s(%d):block_til_ready after blocking on %s open_count=%d\n",
              __FILE__,__LINE__, tty->driver.name, self->open_count);
                         
        if (!retval)
                self->flags |= ASYNC_NORMAL_ACTIVE;
                
        return retval;  
}

/*
 * Function ircomm_tty_open (tty, filp)
 *
 *    This routine is called when a particular tty device is opened. This
 *    routine is mandatory; if this routine is not filled in, the attempted
 *    open will fail with ENODEV.
 */
static int ircomm_tty_open(struct tty_struct *tty, struct file *filp)
{
        struct ircomm_tty_cb *self;
        int line;
        int ret;

        IRDA_DEBUG(2, __FUNCTION__ "()\n");

        MOD_INC_USE_COUNT;
        line = MINOR(tty->device) - tty->driver.minor_start;
        if ((line < 0) || (line >= IRCOMM_TTY_PORTS)) {
                MOD_DEC_USE_COUNT;
                return -ENODEV;
        }

        /* Check if instance already exists */
        self = hashbin_find(ircomm_tty, line, NULL);
        if (!self) {
                /* No, so make new instance */
                self = kmalloc(sizeof(struct ircomm_tty_cb), GFP_KERNEL);
                if (self == NULL) {
                        ERROR(__FUNCTION__"(), kmalloc failed!\n");
                        MOD_DEC_USE_COUNT;
                        return -ENOMEM;
                }
                memset(self, 0, sizeof(struct ircomm_tty_cb));
                
                self->magic = IRCOMM_TTY_MAGIC;
                self->flow = FLOW_STOP;

                self->line = line;
                self->tqueue.routine = ircomm_tty_do_softint;
                self->tqueue.data = self;
                self->max_header_size = 5;
                self->max_data_size = 64-self->max_header_size;
                self->close_delay = 5*HZ/10;
                self->closing_wait = 30*HZ;

                /* Init some important stuff */
                init_timer(&self->watchdog_timer);
                init_waitqueue_head(&self->open_wait);
                init_waitqueue_head(&self->close_wait);

                /* 
                 * Force TTY into raw mode by default which is usually what
                 * we want for IrCOMM and IrLPT. This way applications will
                 * not have to twiddle with printcap etc.  
                 */
                tty->termios->c_iflag = 0;
                tty->termios->c_oflag = 0;

                /* Insert into hash */
                hashbin_insert(ircomm_tty, (irda_queue_t *) self, line, NULL);
        }
        self->open_count++;

        tty->driver_data = self;
        self->tty = tty;

        IRDA_DEBUG(1, __FUNCTION__"(), %s%d, count = %d\n", tty->driver.name, 
                   self->line, self->open_count);

        /* Not really used by us, but lets do it anyway */
        self->tty->low_latency = (self->flags & ASYNC_LOW_LATENCY) ? 1 : 0;

        /*
         * If the port is the middle of closing, bail out now
         */
        if (tty_hung_up_p(filp) ||
            (self->flags & ASYNC_CLOSING)) {
                if (self->flags & ASYNC_CLOSING)
                        interruptible_sleep_on(&self->close_wait);
                /* MOD_DEC_USE_COUNT; "info->tty" will cause this? */
#ifdef SERIAL_DO_RESTART
                return ((self->flags & ASYNC_HUP_NOTIFY) ?
                        -EAGAIN : -ERESTARTSYS);
#else
                return -EAGAIN;
#endif
        }

        /* Check if this is a "normal" ircomm device, or an irlpt device */
        if (line < 0x10) {
                self->service_type = IRCOMM_3_WIRE | IRCOMM_9_WIRE;
                self->settings.service_type = IRCOMM_9_WIRE; /* Default */
                IRDA_DEBUG(2, __FUNCTION__ "(), IrCOMM device\n");
        } else {
                IRDA_DEBUG(2, __FUNCTION__ "(), IrLPT device\n");
                self->service_type = IRCOMM_3_WIRE_RAW;
                self->settings.service_type = IRCOMM_3_WIRE_RAW; /* Default */
        }

        ret = ircomm_tty_startup(self);
        if (ret)
                return ret;

        ret = ircomm_tty_block_til_ready(self, filp);
        if (ret) {
                /* MOD_DEC_USE_COUNT; "info->tty" will cause this? */
                IRDA_DEBUG(2, __FUNCTION__ 
                      "(), returning after block_til_ready with %d\n",
                      ret);

                return ret;
        }

        self->session = current->session;
        self->pgrp = current->pgrp;

        return 0;
}

/*
 * Function ircomm_tty_close (tty, filp)
 *
 *    This routine is called when a particular tty device is closed.
 *
 */
static void ircomm_tty_close(struct tty_struct *tty, struct file *filp)
{
        struct ircomm_tty_cb *self = (struct ircomm_tty_cb *) tty->driver_data;
        unsigned long flags;

        IRDA_DEBUG(0, __FUNCTION__ "()\n");

        if (!tty)
                return;

        save_flags(flags); 
        cli();

        if (tty_hung_up_p(filp)) {
                MOD_DEC_USE_COUNT;
                restore_flags(flags);

                IRDA_DEBUG(0, __FUNCTION__ "(), returning 1\n");
                return;
        }

        ASSERT(self != NULL, return;);
        ASSERT(self->magic == IRCOMM_TTY_MAGIC, return;);

        if ((tty->count == 1) && (self->open_count != 1)) {
                /*
                 * Uh, oh.  tty->count is 1, which means that the tty
                 * structure will be freed.  state->count should always
                 * be one in these conditions.  If it's greater than
                 * one, we've got real problems, since it means the
                 * serial port won't be shutdown.
                 */
                IRDA_DEBUG(0, __FUNCTION__ "(), bad serial port count; "
                           "tty->count is 1, state->count is %d\n", 
                           self->open_count);
                self->open_count = 1;
        }

        if (--self->open_count < 0) {
                ERROR(__FUNCTION__ 
                      "(), bad serial port count for ttys%d: %d\n",
                      self->line, self->open_count);
                self->open_count = 0;
        }
        if (self->open_count) {
                MOD_DEC_USE_COUNT;
                restore_flags(flags);

                IRDA_DEBUG(0, __FUNCTION__ "(), open count > 0\n");
                return;
        }
        self->flags |= ASYNC_CLOSING;

        /*
         * Now we wait for the transmit buffer to clear; and we notify 
         * the line discipline to only process XON/XOFF characters.
         */
        tty->closing = 1;
        if (self->closing_wait != ASYNC_CLOSING_WAIT_NONE)
                tty_wait_until_sent(tty, self->closing_wait);

        ircomm_tty_shutdown(self);

        if (tty->driver.flush_buffer)
                tty->driver.flush_buffer(tty);
        if (tty->ldisc.flush_buffer)
                tty->ldisc.flush_buffer(tty);

        tty->closing = 0;
        self->tty = 0;

        if (self->blocked_open) {
                if (self->close_delay) {
                        current->state = TASK_INTERRUPTIBLE;
                        schedule_timeout(self->close_delay);
                }
                wake_up_interruptible(&self->open_wait);
        }

        self->flags &= ~(ASYNC_NORMAL_ACTIVE|ASYNC_CALLOUT_ACTIVE|
                         ASYNC_CLOSING);
        wake_up_interruptible(&self->close_wait);

        MOD_DEC_USE_COUNT;
        restore_flags(flags);
}

/*
 * Function ircomm_tty_flush_buffer (tty)
 *
 *    
 *
 */
static void ircomm_tty_flush_buffer(struct tty_struct *tty)
{
        struct ircomm_tty_cb *self = (struct ircomm_tty_cb *) tty->driver_data;

        ASSERT(self != NULL, return;);
        ASSERT(self->magic == IRCOMM_TTY_MAGIC, return;);

        /* 
         * Let do_softint() do this to avoid race condition with 
         * do_softint() ;-) 
         */
        queue_task(&self->tqueue, &tq_immediate);
        mark_bh(IMMEDIATE_BH);
}

/*
 * Function ircomm_tty_do_softint (private_)
 *
 *    We use this routine to give the write wakeup to the user at at a
 *    safe time (as fast as possible after write have completed). This 
 *    can be compared to the Tx interrupt.
 */
static void ircomm_tty_do_softint(void *private_)
{
        struct ircomm_tty_cb *self = (struct ircomm_tty_cb *) private_;
        struct tty_struct *tty;
        unsigned long flags;
        struct sk_buff *skb, *ctrl_skb;

        IRDA_DEBUG(2, __FUNCTION__ "()\n");

        if (!self || self->magic != IRCOMM_TTY_MAGIC)
                return;

        tty = self->tty;
        if (!tty)
                return;

        /* Unlink control buffer */
        save_flags(flags);
        cli();

        ctrl_skb = self->ctrl_skb;
        self->ctrl_skb = NULL;

        restore_flags(flags);

        /* Flush control buffer if any */
        if (ctrl_skb && self->flow == FLOW_START)
                ircomm_control_request(self->ircomm, ctrl_skb);

        if (tty->hw_stopped)
                return;

        /* Unlink transmit buffer */
        save_flags(flags);
        cli();
        
        skb = self->tx_skb;
        self->tx_skb = NULL;

        restore_flags(flags);   

        /* Flush transmit buffer if any */
        if (skb)
                ircomm_tty_do_event(self, IRCOMM_TTY_DATA_REQUEST, skb, NULL);
                
        /* Check if user (still) wants to be waken up */
        if ((tty->flags & (1 << TTY_DO_WRITE_WAKEUP)) && 
            tty->ldisc.write_wakeup)
        {
                (tty->ldisc.write_wakeup)(tty);
        }
        wake_up_interruptible(&tty->write_wait);
}

/*
 * Function ircomm_tty_write (tty, from_user, buf, count)
 *
 *    This routine is called by the kernel to write a series of characters
 *    to the tty device. The characters may come from user space or kernel
 *    space. This routine will return the number of characters actually
 *    accepted for writing. This routine is mandatory.
 */
static int ircomm_tty_write(struct tty_struct *tty, int from_user,
                            const unsigned char *buf, int count)
{
        struct ircomm_tty_cb *self = (struct ircomm_tty_cb *) tty->driver_data;
        unsigned long flags;
        struct sk_buff *skb;
        int tailroom = 0;
        int len = 0;
        int size;

        IRDA_DEBUG(2, __FUNCTION__ "(), count=%d, hw_stopped=%d\n", count,
                   tty->hw_stopped);

        ASSERT(self != NULL, return -1;);
        ASSERT(self->magic == IRCOMM_TTY_MAGIC, return -1;);

        save_flags(flags);
        cli();

        /* Fetch current transmit buffer */
        skb = self->tx_skb;

        /*  
         * Send out all the data we get, possibly as multiple fragmented
         * frames, but this will only happen if the data is larger than the
         * max data size. The normal case however is just the opposite, and
         * this function may be called multiple times, and will then actually
         * defragment the data and send it out as one packet as soon as 
         * possible, but at a safer point in time
         */
        while (count) {
                size = count;

                /* Adjust data size to the max data size */
                if (size > self->max_data_size)
                        size = self->max_data_size;
                
                /* 
                 * Do we already have a buffer ready for transmit, or do
                 * we need to allocate a new frame 
                 */
                if (skb) {                      
                        /* 
                         * Any room for more data at the end of the current 
                         * transmit buffer? Cannot use skb_tailroom, since
                         * dev_alloc_skb gives us a larger skb than we 
                         * requested
                         */
                        if ((tailroom = (self->max_data_size-skb->len)) > 0) {
                                /* Adjust data to tailroom */
                                if (size > tailroom)
                                        size = tailroom;
                        } else {
                                /* 
                                 * Current transmit frame is full, so break 
                                 * out, so we can send it as soon as possible
                                 */
                                break;
                        }
                } else {
                        /* Prepare a full sized frame */
                        skb = dev_alloc_skb(self->max_data_size+
                                            self->max_header_size);
                        if (!skb) {
                                restore_flags(flags);
                                return -ENOBUFS;
                        }
                        skb_reserve(skb, self->max_header_size);
                        self->tx_skb = skb;
                }
                
                /* Copy data */
                if (from_user)
                        copy_from_user(skb_put(skb,size), buf+len, size);
                else
                        memcpy(skb_put(skb,size), buf+len, size);
                
                count -= size;
                len += size;
        }

        restore_flags(flags);

        /*     
         * Schedule a new thread which will transmit the frame as soon
         * as possible, but at a safe point in time. We do this so the
         * "user" can give us data multiple times, as PPP does (because of
         * its 256 byte tx buffer). We will then defragment and send out
         * all this data as one single packet.  
         */
        queue_task(&self->tqueue, &tq_immediate);
        mark_bh(IMMEDIATE_BH);
        
        return len;
}

/*
 * Function ircomm_tty_write_room (tty)
 *
 *    This routine returns the numbers of characters the tty driver will
 *    accept for queuing to be written. This number is subject to change as
 *    output buffers get emptied, or if the output flow control is acted.
 */
static int ircomm_tty_write_room(struct tty_struct *tty)
{
        struct ircomm_tty_cb *self = (struct ircomm_tty_cb *) tty->driver_data;
        unsigned long flags;
        int ret;

        ASSERT(self != NULL, return -1;);
        ASSERT(self->magic == IRCOMM_TTY_MAGIC, return -1;);

        /* Check if we are allowed to transmit any data */
        if (tty->hw_stopped)
                ret = 0;
        else {
                save_flags(flags);
                cli();
                if (self->tx_skb)
                        ret = self->max_data_size - self->tx_skb->len;
                else
                        ret = self->max_data_size;
                restore_flags(flags);
        }
        IRDA_DEBUG(2, __FUNCTION__ "(), ret=%d\n", ret);

        return ret;
}

/*
 * Function ircomm_tty_wait_until_sent (tty, timeout)
 *
 *    This routine waits until the device has written out all of the
 *    characters in its transmitter FIFO.
 */
static void ircomm_tty_wait_until_sent(struct tty_struct *tty, int timeout)
{
        struct ircomm_tty_cb *self = (struct ircomm_tty_cb *) tty->driver_data;
        unsigned long orig_jiffies, poll_time;
        
        IRDA_DEBUG(2, __FUNCTION__ "()\n");

        ASSERT(self != NULL, return;);
        ASSERT(self->magic == IRCOMM_TTY_MAGIC, return;);

        orig_jiffies = jiffies;

        /* Set poll time to 200 ms */
        poll_time = IRDA_MIN(timeout, MSECS_TO_JIFFIES(200));

        while (self->tx_skb && self->tx_skb->len) {
                current->state = TASK_INTERRUPTIBLE;
                schedule_timeout(poll_time);
                if (signal_pending(current))
                        break;
                if (timeout && time_after(jiffies, orig_jiffies + timeout))
                        break;
        }
        current->state = TASK_RUNNING;
}

/*
 * Function ircomm_tty_throttle (tty)
 *
 *    This routine notifies the tty driver that input buffers for the line
 *    discipline are close to full, and it should somehow signal that no
 *    more characters should be sent to the tty.  
 */
static void ircomm_tty_throttle(struct tty_struct *tty)
{
        struct ircomm_tty_cb *self = (struct ircomm_tty_cb *) tty->driver_data;

        IRDA_DEBUG(2, __FUNCTION__ "()\n");

        ASSERT(self != NULL, return;);
        ASSERT(self->magic == IRCOMM_TTY_MAGIC, return;);

        /* Software flow control? */
        if (I_IXOFF(tty))
                ircomm_tty_send_xchar(tty, STOP_CHAR(tty));
        
        /* Hardware flow control? */
        if (tty->termios->c_cflag & CRTSCTS) {
                self->settings.dte &= ~IRCOMM_RTS;
                self->settings.dte |= IRCOMM_DELTA_RTS;
        
                ircomm_param_request(self, IRCOMM_DTE, TRUE);
        }

        ircomm_flow_request(self->ircomm, FLOW_STOP);
}

/*
 * Function ircomm_tty_unthrottle (tty)
 *
 *    This routine notifies the tty drivers that it should signals that
 *    characters can now be sent to the tty without fear of overrunning the
 *    input buffers of the line disciplines.
 */
static void ircomm_tty_unthrottle(struct tty_struct *tty)
{
        struct ircomm_tty_cb *self = (struct ircomm_tty_cb *) tty->driver_data;

        IRDA_DEBUG(2, __FUNCTION__ "()\n");

        ASSERT(self != NULL, return;);
        ASSERT(self->magic == IRCOMM_TTY_MAGIC, return;);

        /* Using software flow control? */
        if (I_IXOFF(tty)) {
                ircomm_tty_send_xchar(tty, START_CHAR(tty));
        }

        /* Using hardware flow control? */
        if (tty->termios->c_cflag & CRTSCTS) {
                self->settings.dte |= (IRCOMM_RTS|IRCOMM_DELTA_RTS);

                ircomm_param_request(self, IRCOMM_DTE, TRUE);
                IRDA_DEBUG(1, __FUNCTION__"(), FLOW_START\n");
        }
        ircomm_flow_request(self->ircomm, FLOW_START);
}

/*
 * Function ircomm_tty_chars_in_buffer (tty)
 *
 *    Indicates if there are any data in the buffer
 *
 */
static int ircomm_tty_chars_in_buffer(struct tty_struct *tty)
{
        struct ircomm_tty_cb *self = (struct ircomm_tty_cb *) tty->driver_data;
        unsigned long flags;
        int len = 0;

        ASSERT(self != NULL, return -1;);
        ASSERT(self->magic == IRCOMM_TTY_MAGIC, return -1;);

        save_flags(flags);
        cli();

        if (self->tx_skb)
                len = self->tx_skb->len;

        restore_flags(flags);

        return len;
}

static void ircomm_tty_shutdown(struct ircomm_tty_cb *self)
{
        unsigned long flags;

        ASSERT(self != NULL, return;);
        ASSERT(self->magic == IRCOMM_TTY_MAGIC, return;);

        IRDA_DEBUG(0, __FUNCTION__ "()\n");
        
        if (!(self->flags & ASYNC_INITIALIZED))
                return;

        save_flags(flags);
        cli();

        del_timer(&self->watchdog_timer);
        
        /* Free parameter buffer */
        if (self->ctrl_skb) {
                dev_kfree_skb(self->ctrl_skb);
                self->ctrl_skb = NULL;
        }

        /* Free transmit buffer */
        if (self->tx_skb) {
                dev_kfree_skb(self->tx_skb);
                self->tx_skb = NULL;
        }

        ircomm_tty_detach_cable(self);

        if (self->ircomm) {
                ircomm_close(self->ircomm);
                self->ircomm = NULL;
        }
        self->flags &= ~ASYNC_INITIALIZED;

        restore_flags(flags);
}

/*
 * Function ircomm_tty_hangup (tty)
 *
 *    This routine notifies the tty driver that it should hangup the tty
 *    device.
 * 
 */
static void ircomm_tty_hangup(struct tty_struct *tty)
{
        struct ircomm_tty_cb *self = (struct ircomm_tty_cb *) tty->driver_data;

        IRDA_DEBUG(0, __FUNCTION__"()\n");

        ASSERT(self != NULL, return;);
        ASSERT(self->magic == IRCOMM_TTY_MAGIC, return;);

        if (!tty)
                return;

        /* ircomm_tty_flush_buffer(tty); */
        ircomm_tty_shutdown(self);

        self->flags &= ~(ASYNC_NORMAL_ACTIVE|ASYNC_CALLOUT_ACTIVE);
        self->tty = 0;
        self->open_count = 0;
        wake_up_interruptible(&self->open_wait);
}

/*
 * Function ircomm_tty_send_xchar (tty, ch)
 *
 *    This routine is used to send a high-priority XON/XOFF character to
 *    the device.
 */
static void ircomm_tty_send_xchar(struct tty_struct *tty, char ch)
{
        IRDA_DEBUG(0, __FUNCTION__"(), not impl\n");
}

/*
 * Function ircomm_tty_start (tty)
 *
 *    This routine notifies the tty driver that it resume sending
 *    characters to the tty device.  
 */
void ircomm_tty_start(struct tty_struct *tty)
{
        struct ircomm_tty_cb *self = (struct ircomm_tty_cb *) tty->driver_data;

        ircomm_flow_request(self->ircomm, FLOW_START);
}

/*
 * Function ircomm_tty_stop (tty)
 *
 *     This routine notifies the tty driver that it should stop outputting
 *     characters to the tty device. 
 */
void ircomm_tty_stop(struct tty_struct *tty) 
{
        struct ircomm_tty_cb *self = (struct ircomm_tty_cb *) tty->driver_data;

        ASSERT(self != NULL, return;);
        ASSERT(self->magic == IRCOMM_TTY_MAGIC, return;);

        ircomm_flow_request(self->ircomm, FLOW_STOP);
}

/*
 * Function ircomm_check_modem_status (self)
 *
 *    Check for any changes in the DCE's line settings. This function should
 *    be called whenever the dce parameter settings changes, to update the
 *    flow control settings and other things
 */
void ircomm_tty_check_modem_status(struct ircomm_tty_cb *self)
{
        struct tty_struct *tty;
        int status;

        IRDA_DEBUG(0, __FUNCTION__ "()\n");

        ASSERT(self != NULL, return;);
        ASSERT(self->magic == IRCOMM_TTY_MAGIC, return;);

        tty = self->tty;

        status = self->settings.dce;

        if (status & IRCOMM_DCE_DELTA_ANY) {
                /*wake_up_interruptible(&self->delta_msr_wait);*/
        }
        if ((self->flags & ASYNC_CHECK_CD) && (status & IRCOMM_DELTA_CD)) {
                IRDA_DEBUG(2, __FUNCTION__ 
                           "(), ircomm%d CD now %s...\n", self->line,
                           (status & IRCOMM_CD) ? "on" : "off");

                if (status & IRCOMM_CD) {
                        wake_up_interruptible(&self->open_wait);
                } else if (!((self->flags & ASYNC_CALLOUT_ACTIVE) &&
                           (self->flags & ASYNC_CALLOUT_NOHUP))) 
                {
                        IRDA_DEBUG(2, __FUNCTION__ 
                                   "(), Doing serial hangup..\n");
                        if (tty)
                                tty_hangup(tty);

                        /* Hangup will remote the tty, so better break out */
                        return;
                }
        }
        if (self->flags & ASYNC_CTS_FLOW) {
                if (tty->hw_stopped) {
                        if (status & IRCOMM_CTS) {
                                IRDA_DEBUG(2, __FUNCTION__ 
                                           "(), CTS tx start...\n");
                                tty->hw_stopped = 0;
                                
                                /* Wake up processes blocked on open */
                                wake_up_interruptible(&self->open_wait);

                                queue_task(&self->tqueue, &tq_immediate);
                                mark_bh(IMMEDIATE_BH);
                                return;
                        }
                } else {
                        if (!(status & IRCOMM_CTS)) {
                                IRDA_DEBUG(2, __FUNCTION__ 
                                           "(), CTS tx stop...\n");
                                tty->hw_stopped = 1;
                        }
                }
        }
}

/*
 * Function ircomm_tty_data_indication (instance, sap, skb)
 *
 *    Handle incomming data, and deliver it to the line discipline
 *
 */
static int ircomm_tty_data_indication(void *instance, void *sap,
                                      struct sk_buff *skb)
{
        struct ircomm_tty_cb *self = (struct ircomm_tty_cb *) instance;

        IRDA_DEBUG(2, __FUNCTION__"()\n");
        
        ASSERT(self != NULL, return -1;);
        ASSERT(self->magic == IRCOMM_TTY_MAGIC, return -1;);
        ASSERT(skb != NULL, return -1;);

        if (!self->tty) {
                IRDA_DEBUG(0, __FUNCTION__ "(), no tty!\n");
                dev_kfree_skb(skb);
                return 0;
        }

        /* 
         * If we receive data when hardware is stopped then something is wrong.
         * We try to poll the peers line settings to check if we are up todate.
         * Devices like WinCE can do this, and since they don't send any 
         * params, we can just as well declare the hardware for running.
         */
        if (self->tty->hw_stopped && (self->flow == FLOW_START)) {
                IRDA_DEBUG(0, __FUNCTION__ "(), polling for line settings!\n");
                ircomm_param_request(self, IRCOMM_POLL, TRUE);

                /* We can just as well declare the hardware for running */
                ircomm_tty_send_initial_parameters(self);
                ircomm_tty_link_established(self);
        }

        /* 
         * Just give it over to the line discipline. There is no need to
         * involve the flip buffers, since we are not running in an interrupt 
         * handler
         */
        self->tty->ldisc.receive_buf(self->tty, skb->data, NULL, skb->len);
        dev_kfree_skb(skb);

        return 0;
}

/*
 * Function ircomm_tty_control_indication (instance, sap, skb)
 *
 *    Parse all incomming parameters (easy!)
 *
 */
static int ircomm_tty_control_indication(void *instance, void *sap,
                                         struct sk_buff *skb)
{
        struct ircomm_tty_cb *self = (struct ircomm_tty_cb *) instance;
        int clen;

        IRDA_DEBUG(4, __FUNCTION__"()\n");
        
        ASSERT(self != NULL, return -1;);
        ASSERT(self->magic == IRCOMM_TTY_MAGIC, return -1;);
        ASSERT(skb != NULL, return -1;);

        clen = skb->data[0];

        irda_param_extract_all(self, skb->data+1, IRDA_MIN(skb->len-1, clen), 
                               &ircomm_param_info);
        dev_kfree_skb(skb);

        return 0;
}

/*
 * Function ircomm_tty_flow_indication (instance, sap, cmd)
 *
 *    This function is called by IrTTP when it wants us to slow down the
 *    transmission of data. We just mark the hardware as stopped, and wait
 *    for IrTTP to notify us that things are OK again.
 */
static void ircomm_tty_flow_indication(void *instance, void *sap, 
                                       LOCAL_FLOW cmd)
{
        struct ircomm_tty_cb *self = (struct ircomm_tty_cb *) instance;
        struct tty_struct *tty;

        ASSERT(self != NULL, return;);
        ASSERT(self->magic == IRCOMM_TTY_MAGIC, return;);

        tty = self->tty;

        switch (cmd) {
        case FLOW_START:
                IRDA_DEBUG(2, __FUNCTION__ "(), hw start!\n");
                tty->hw_stopped = 0;

                /* ircomm_tty_do_softint will take care of the rest */
                queue_task(&self->tqueue, &tq_immediate);
                mark_bh(IMMEDIATE_BH);
                break;
        default:  /* If we get here, something is very wrong, better stop */
        case FLOW_STOP:
                IRDA_DEBUG(2, __FUNCTION__ "(), hw stopped!\n");
                tty->hw_stopped = 1;
                break;
        }
        self->flow = cmd;
}

static int ircomm_tty_line_info(struct ircomm_tty_cb *self, char *buf)
{
        int  ret=0;

        ret += sprintf(buf+ret, "State: %s\n", ircomm_tty_state[self->state]);

        ret += sprintf(buf+ret, "Service type: ");
        if (self->service_type & IRCOMM_9_WIRE)
                ret += sprintf(buf+ret, "9_WIRE");
        else if (self->service_type & IRCOMM_3_WIRE)
                ret += sprintf(buf+ret, "3_WIRE");
        else if (self->service_type & IRCOMM_3_WIRE_RAW)
                ret += sprintf(buf+ret, "3_WIRE_RAW");
        else
                ret += sprintf(buf+ret, "No common service type!\n");
        ret += sprintf(buf+ret, "\n");

        ret += sprintf(buf+ret, "Port name: %s\n", self->settings.port_name);

        ret += sprintf(buf+ret, "DTE status: ");        
        if (self->settings.dte & IRCOMM_RTS)
                ret += sprintf(buf+ret, "RTS|");
        if (self->settings.dte & IRCOMM_DTR)
                ret += sprintf(buf+ret, "DTR|");
        if (self->settings.dte)
                ret--; /* remove the last | */
        ret += sprintf(buf+ret, "\n");

        ret += sprintf(buf+ret, "DCE status: ");
        if (self->settings.dce & IRCOMM_CTS)
                ret += sprintf(buf+ret, "CTS|");
        if (self->settings.dce & IRCOMM_DSR)
                ret += sprintf(buf+ret, "DSR|");
        if (self->settings.dce & IRCOMM_CD)
                ret += sprintf(buf+ret, "CD|");
        if (self->settings.dce & IRCOMM_RI) 
                ret += sprintf(buf+ret, "RI|");
        if (self->settings.dce)
                ret--; /* remove the last | */
        ret += sprintf(buf+ret, "\n");

        ret += sprintf(buf+ret, "Configuration: ");
        if (!self->settings.null_modem)
                ret += sprintf(buf+ret, "DTE <-> DCE\n");
        else
                ret += sprintf(buf+ret, 
                               "DTE <-> DTE (null modem emulation)\n");

        ret += sprintf(buf+ret, "Data rate: %d\n", self->settings.data_rate);

        ret += sprintf(buf+ret, "Flow control: ");
        if (self->settings.flow_control & IRCOMM_XON_XOFF_IN)
                ret += sprintf(buf+ret, "XON_XOFF_IN|");
        if (self->settings.flow_control & IRCOMM_XON_XOFF_OUT)
                ret += sprintf(buf+ret, "XON_XOFF_OUT|");
        if (self->settings.flow_control & IRCOMM_RTS_CTS_IN)
                ret += sprintf(buf+ret, "RTS_CTS_IN|");
        if (self->settings.flow_control & IRCOMM_RTS_CTS_OUT)
                ret += sprintf(buf+ret, "RTS_CTS_OUT|");
        if (self->settings.flow_control & IRCOMM_DSR_DTR_IN)
                ret += sprintf(buf+ret, "DSR_DTR_IN|");
        if (self->settings.flow_control & IRCOMM_DSR_DTR_OUT)
                ret += sprintf(buf+ret, "DSR_DTR_OUT|");
        if (self->settings.flow_control & IRCOMM_ENQ_ACK_IN)
                ret += sprintf(buf+ret, "ENQ_ACK_IN|");
        if (self->settings.flow_control & IRCOMM_ENQ_ACK_OUT)
                ret += sprintf(buf+ret, "ENQ_ACK_OUT|");
        if (self->settings.flow_control)
                ret--; /* remove the last | */
        ret += sprintf(buf+ret, "\n");

        ret += sprintf(buf+ret, "Flags: ");
        if (self->flags & ASYNC_CTS_FLOW)
                ret += sprintf(buf+ret, "ASYNC_CTS_FLOW|");
        if (self->flags & ASYNC_CHECK_CD)
                ret += sprintf(buf+ret, "ASYNC_CHECK_CD|");
        if (self->flags & ASYNC_INITIALIZED)
                ret += sprintf(buf+ret, "ASYNC_INITIALIZED|");
        if (self->flags & ASYNC_LOW_LATENCY)
                ret += sprintf(buf+ret, "ASYNC_LOW_LATENCY|");
        if (self->flags & ASYNC_CLOSING)
                ret += sprintf(buf+ret, "ASYNC_CLOSING|");
        if (self->flags & ASYNC_NORMAL_ACTIVE)
                ret += sprintf(buf+ret, "ASYNC_NORMAL_ACTIVE|");
        if (self->flags & ASYNC_CALLOUT_ACTIVE)
                ret += sprintf(buf+ret, "ASYNC_CALLOUT_ACTIVE|");
        if (self->flags)
                ret--; /* remove the last | */
        ret += sprintf(buf+ret, "\n");

        ret += sprintf(buf+ret, "Role: %s\n", self->client ? 
                       "client" : "server");
        ret += sprintf(buf+ret, "Open count: %d\n", self->open_count);
        ret += sprintf(buf+ret, "Max data size: %d\n", self->max_data_size);
        ret += sprintf(buf+ret, "Max header size: %d\n", self->max_header_size);
                
        if (self->tty)
                ret += sprintf(buf+ret, "Hardware: %s\n", 
                               self->tty->hw_stopped ? "Stopped" : "Running");

        ret += sprintf(buf+ret, "\n");
        return ret;
}


/*
 * Function ircomm_tty_read_proc (buf, start, offset, len, eof, unused)
 *
 *    
 *
 */
#ifdef CONFIG_PROC_FS
static int ircomm_tty_read_proc(char *buf, char **start, off_t offset, int len,
                                int *eof, void *unused)
{
        struct ircomm_tty_cb *self;
        int count = 0, l;
        off_t begin = 0;

        self = (struct ircomm_tty_cb *) hashbin_get_first(ircomm_tty);
        while ((self != NULL) && (count < 4000)) {
                if (self->magic != IRCOMM_TTY_MAGIC)
                        return 0;

                l = ircomm_tty_line_info(self, buf + count);
                count += l;
                if (count+begin > offset+len)
                        goto done;
                if (count+begin < offset) {
                        begin += count;
                        count = 0;
                }
                                
                self = (struct ircomm_tty_cb *) hashbin_get_next(ircomm_tty);
        }
        *eof = 1;
done:
        if (offset >= count+begin)
                return 0;
        *start = buf + (offset-begin);
        return ((len < begin+count-offset) ? len : begin+count-offset);
}
#endif /* CONFIG_PROC_FS */

#ifdef MODULE
MODULE_AUTHOR("Dag Brattli <dagb@cs.uit.no>");
MODULE_DESCRIPTION("IrCOMM serial TTY driver");

int init_module(void) 
{
        return ircomm_tty_init();
}

void cleanup_module(void)
{
        ircomm_tty_cleanup();
}

#endif /* MODULE */