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generic_serial.c

/*
 *  generic_serial.c
 *
 *  Copyright (C) 1998/1999 R.E.Wolff@BitWizard.nl
 *
 *  written for the SX serial driver.
 *     Contains the code that should be shared over all the serial drivers.
 *
 *  Credit for the idea to do it this way might go to Alan Cox. 
 *
 *
 *  Version 0.1 -- December, 1998. Initial version.
 *  Version 0.2 -- March, 1999.    Some more routines. Bugfixes. Etc.
 *  Version 0.5 -- August, 1999.   Some more fixes. Reformat for Linus.
 *
 *  BitWizard is actively maintaining this file. We sometimes find
 *  that someone submitted changes to this file. We really appreciate
 *  your help, but please submit changes through us. We're doing our
 *  best to be responsive.  -- REW
 * */

#include <linux/module.h>
#include <linux/kernel.h>
#include <linux/tty.h>
#include <linux/serial.h>
#include <linux/mm.h>
#include <linux/generic_serial.h>
#include <linux/interrupt.h>
#include <linux/tty_flip.h>
#include <linux/delay.h>
#include <asm/semaphore.h>
#include <asm/uaccess.h>

#define DEBUG 

static int gs_debug;

#ifdef DEBUG
#define gs_dprintk(f, str...) if (gs_debug & f) printk (str)
#else
#define gs_dprintk(f, str...) /* nothing */
#endif

#define func_enter() gs_dprintk (GS_DEBUG_FLOW, "gs: enter %s\n", __FUNCTION__)
#define func_exit()  gs_dprintk (GS_DEBUG_FLOW, "gs: exit  %s\n", __FUNCTION__)

#define RS_EVENT_WRITE_WAKEUP 1

module_param(gs_debug, int, 0644);


void gs_put_char(struct tty_struct * tty, unsigned char ch)
{
      struct gs_port *port;

      func_enter (); 

      if (!tty) return;

      port = tty->driver_data;

      if (!port) return;

      if (! (port->flags & ASYNC_INITIALIZED)) return;

      /* Take a lock on the serial tranmit buffer! */
      mutex_lock(& port->port_write_mutex);

      if (port->xmit_cnt >= SERIAL_XMIT_SIZE - 1) {
            /* Sorry, buffer is full, drop character. Update statistics???? -- REW */
            mutex_unlock(&port->port_write_mutex);
            return;
      }

      port->xmit_buf[port->xmit_head++] = ch;
      port->xmit_head &= SERIAL_XMIT_SIZE - 1;
      port->xmit_cnt++;  /* Characters in buffer */

      mutex_unlock(&port->port_write_mutex);
      func_exit ();
}


/*
> Problems to take into account are:
>       -1- Interrupts that empty part of the buffer.
>       -2- page faults on the access to userspace. 
>       -3- Other processes that are also trying to do a "write". 
*/

int gs_write(struct tty_struct * tty, 
                    const unsigned char *buf, int count)
{
      struct gs_port *port;
      int c, total = 0;
      int t;

      func_enter ();

      if (!tty) return 0;

      port = tty->driver_data;

      if (!port) return 0;

      if (! (port->flags & ASYNC_INITIALIZED))
            return 0;

      /* get exclusive "write" access to this port (problem 3) */
      /* This is not a spinlock because we can have a disk access (page 
             fault) in copy_from_user */
      mutex_lock(& port->port_write_mutex);

      while (1) {

            c = count;
 
            /* This is safe because we "OWN" the "head". Noone else can 
               change the "head": we own the port_write_mutex. */
            /* Don't overrun the end of the buffer */
            t = SERIAL_XMIT_SIZE - port->xmit_head;
            if (t < c) c = t;
 
            /* This is safe because the xmit_cnt can only decrease. This 
               would increase "t", so we might copy too little chars. */
            /* Don't copy past the "head" of the buffer */
            t = SERIAL_XMIT_SIZE - 1 - port->xmit_cnt;
            if (t < c) c = t;
 
            /* Can't copy more? break out! */
            if (c <= 0) break;

            memcpy (port->xmit_buf + port->xmit_head, buf, c);

            port -> xmit_cnt += c;
            port -> xmit_head = (port->xmit_head + c) & (SERIAL_XMIT_SIZE -1);
            buf += c;
            count -= c;
            total += c;
      }
      mutex_unlock(& port->port_write_mutex);

      gs_dprintk (GS_DEBUG_WRITE, "write: interrupts are %s\n", 
                  (port->flags & GS_TX_INTEN)?"enabled": "disabled"); 

      if (port->xmit_cnt && 
          !tty->stopped && 
          !tty->hw_stopped &&
          !(port->flags & GS_TX_INTEN)) {
            port->flags |= GS_TX_INTEN;
            port->rd->enable_tx_interrupts (port);
      }
      func_exit ();
      return total;
}



int gs_write_room(struct tty_struct * tty)
{
      struct gs_port *port = tty->driver_data;
      int ret;

      func_enter ();
      ret = SERIAL_XMIT_SIZE - port->xmit_cnt - 1;
      if (ret < 0)
            ret = 0;
      func_exit ();
      return ret;
}


int gs_chars_in_buffer(struct tty_struct *tty)
{
      struct gs_port *port = tty->driver_data;
      func_enter ();

      func_exit ();
      return port->xmit_cnt;
}


static int gs_real_chars_in_buffer(struct tty_struct *tty)
{
      struct gs_port *port;
      func_enter ();

      if (!tty) return 0;
      port = tty->driver_data;

      if (!port->rd) return 0;
      if (!port->rd->chars_in_buffer) return 0;

      func_exit ();
      return port->xmit_cnt + port->rd->chars_in_buffer (port);
}


static int gs_wait_tx_flushed (void * ptr, unsigned long timeout) 
{
      struct gs_port *port = ptr;
      unsigned long end_jiffies;
      int jiffies_to_transmit, charsleft = 0, rv = 0;
      int rcib;

      func_enter();

      gs_dprintk (GS_DEBUG_FLUSH, "port=%p.\n", port);
      if (port) {
            gs_dprintk (GS_DEBUG_FLUSH, "xmit_cnt=%x, xmit_buf=%p, tty=%p.\n", 
            port->xmit_cnt, port->xmit_buf, port->tty);
      }

      if (!port || port->xmit_cnt < 0 || !port->xmit_buf) {
            gs_dprintk (GS_DEBUG_FLUSH, "ERROR: !port, !port->xmit_buf or prot->xmit_cnt < 0.\n");
            func_exit();
            return -EINVAL;  /* This is an error which we don't know how to handle. */
      }

      rcib = gs_real_chars_in_buffer(port->tty);

      if(rcib <= 0) {
            gs_dprintk (GS_DEBUG_FLUSH, "nothing to wait for.\n");
            func_exit();
            return rv;
      }
      /* stop trying: now + twice the time it would normally take +  seconds */
      if (timeout == 0) timeout = MAX_SCHEDULE_TIMEOUT;
      end_jiffies  = jiffies; 
      if (timeout !=  MAX_SCHEDULE_TIMEOUT)
            end_jiffies += port->baud?(2 * rcib * 10 * HZ / port->baud):0;
      end_jiffies += timeout;

      gs_dprintk (GS_DEBUG_FLUSH, "now=%lx, end=%lx (%ld).\n", 
                jiffies, end_jiffies, end_jiffies-jiffies); 

      /* the expression is actually jiffies < end_jiffies, but that won't
         work around the wraparound. Tricky eh? */
      while ((charsleft = gs_real_chars_in_buffer (port->tty)) &&
              time_after (end_jiffies, jiffies)) {
            /* Units check: 
               chars * (bits/char) * (jiffies /sec) / (bits/sec) = jiffies!
               check! */

            charsleft += 16; /* Allow 16 chars more to be transmitted ... */
            jiffies_to_transmit = port->baud?(1 + charsleft * 10 * HZ / port->baud):0;
            /*                                ^^^ Round up.... */
            if (jiffies_to_transmit <= 0) jiffies_to_transmit = 1;

            gs_dprintk (GS_DEBUG_FLUSH, "Expect to finish in %d jiffies "
                      "(%d chars).\n", jiffies_to_transmit, charsleft); 

            msleep_interruptible(jiffies_to_msecs(jiffies_to_transmit));
            if (signal_pending (current)) {
                  gs_dprintk (GS_DEBUG_FLUSH, "Signal pending. Bombing out: "); 
                  rv = -EINTR;
                  break;
            }
      }

      gs_dprintk (GS_DEBUG_FLUSH, "charsleft = %d.\n", charsleft); 
      set_current_state (TASK_RUNNING);

      func_exit();
      return rv;
}



void gs_flush_buffer(struct tty_struct *tty)
{
      struct gs_port *port;
      unsigned long flags;

      func_enter ();

      if (!tty) return;

      port = tty->driver_data;

      if (!port) return;

      /* XXX Would the write semaphore do? */
      spin_lock_irqsave (&port->driver_lock, flags);
      port->xmit_cnt = port->xmit_head = port->xmit_tail = 0;
      spin_unlock_irqrestore (&port->driver_lock, flags);

      tty_wakeup(tty);
      func_exit ();
}


void gs_flush_chars(struct tty_struct * tty)
{
      struct gs_port *port;

      func_enter ();

      if (!tty) return;

      port = tty->driver_data;

      if (!port) return;

      if (port->xmit_cnt <= 0 || tty->stopped || tty->hw_stopped ||
          !port->xmit_buf) {
            func_exit ();
            return;
      }

      /* Beats me -- REW */
      port->flags |= GS_TX_INTEN;
      port->rd->enable_tx_interrupts (port);
      func_exit ();
}


void gs_stop(struct tty_struct * tty)
{
      struct gs_port *port;

      func_enter ();

      if (!tty) return;

      port = tty->driver_data;

      if (!port) return;

      if (port->xmit_cnt && 
          port->xmit_buf && 
          (port->flags & GS_TX_INTEN) ) {
            port->flags &= ~GS_TX_INTEN;
            port->rd->disable_tx_interrupts (port);
      }
      func_exit ();
}


void gs_start(struct tty_struct * tty)
{
      struct gs_port *port;

      if (!tty) return;

      port = tty->driver_data;

      if (!port) return;

      if (port->xmit_cnt && 
          port->xmit_buf && 
          !(port->flags & GS_TX_INTEN) ) {
            port->flags |= GS_TX_INTEN;
            port->rd->enable_tx_interrupts (port);
      }
      func_exit ();
}


static void gs_shutdown_port (struct gs_port *port)
{
      unsigned long flags;

      func_enter();
      
      if (!port) return;
      
      if (!(port->flags & ASYNC_INITIALIZED))
            return;

      spin_lock_irqsave(&port->driver_lock, flags);

      if (port->xmit_buf) {
            free_page((unsigned long) port->xmit_buf);
            port->xmit_buf = NULL;
      }

      if (port->tty)
            set_bit(TTY_IO_ERROR, &port->tty->flags);

      port->rd->shutdown_port (port);

      port->flags &= ~ASYNC_INITIALIZED;
      spin_unlock_irqrestore(&port->driver_lock, flags);

      func_exit();
}


void gs_hangup(struct tty_struct *tty)
{
      struct gs_port   *port;

      func_enter ();

      if (!tty) return;

      port = tty->driver_data;
      tty = port->tty;
      if (!tty) 
            return;

      gs_shutdown_port (port);
      port->flags &= ~(ASYNC_NORMAL_ACTIVE|GS_ACTIVE);
      port->tty = NULL;
      port->count = 0;

      wake_up_interruptible(&port->open_wait);
      func_exit ();
}


int gs_block_til_ready(void *port_, struct file * filp)
{
      struct gs_port *port = port_;
      DECLARE_WAITQUEUE(wait, current);
      int    retval;
      int    do_clocal = 0;
      int    CD;
      struct tty_struct *tty;
      unsigned long flags;

      func_enter ();

      if (!port) return 0;

      tty = port->tty;

      if (!tty) return 0;

      gs_dprintk (GS_DEBUG_BTR, "Entering gs_block_till_ready.\n"); 
      /*
       * If the device is in the middle of being closed, then block
       * until it's done, and then try again.
       */
      if (tty_hung_up_p(filp) || port->flags & ASYNC_CLOSING) {
            interruptible_sleep_on(&port->close_wait);
            if (port->flags & ASYNC_HUP_NOTIFY)
                  return -EAGAIN;
            else
                  return -ERESTARTSYS;
      }

      gs_dprintk (GS_DEBUG_BTR, "after hung up\n"); 

      /*
       * 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))) {
            port->flags |= ASYNC_NORMAL_ACTIVE;
            return 0;
      }

      gs_dprintk (GS_DEBUG_BTR, "after nonblock\n"); 
 
      if (C_CLOCAL(tty))
            do_clocal = 1;

      /*
       * Block waiting for the carrier detect and the line to become
       * free (i.e., not in use by the callout).  While we are in
       * this loop, port->count is dropped by one, so that
       * rs_close() knows when to free things.  We restore it upon
       * exit, either normal or abnormal.
       */
      retval = 0;

      add_wait_queue(&port->open_wait, &wait);

      gs_dprintk (GS_DEBUG_BTR, "after add waitq.\n"); 
      spin_lock_irqsave(&port->driver_lock, flags);
      if (!tty_hung_up_p(filp)) {
            port->count--;
      }
      spin_unlock_irqrestore(&port->driver_lock, flags);
      port->blocked_open++;
      while (1) {
            CD = port->rd->get_CD (port);
            gs_dprintk (GS_DEBUG_BTR, "CD is now %d.\n", CD);
            set_current_state (TASK_INTERRUPTIBLE);
            if (tty_hung_up_p(filp) ||
                !(port->flags & ASYNC_INITIALIZED)) {
                  if (port->flags & ASYNC_HUP_NOTIFY)
                        retval = -EAGAIN;
                  else
                        retval = -ERESTARTSYS;
                  break;
            }
            if (!(port->flags & ASYNC_CLOSING) &&
                (do_clocal || CD))
                  break;
            gs_dprintk (GS_DEBUG_BTR, "signal_pending is now: %d (%lx)\n", 
            (int)signal_pending (current), *(long*)(&current->blocked)); 
            if (signal_pending(current)) {
                  retval = -ERESTARTSYS;
                  break;
            }
            schedule();
      }
      gs_dprintk (GS_DEBUG_BTR, "Got out of the loop. (%d)\n",
                port->blocked_open);
      set_current_state (TASK_RUNNING);
      remove_wait_queue(&port->open_wait, &wait);
      if (!tty_hung_up_p(filp)) {
            port->count++;
      }
      port->blocked_open--;
      if (retval)
            return retval;

      port->flags |= ASYNC_NORMAL_ACTIVE;
      func_exit ();
      return 0;
}                  


void gs_close(struct tty_struct * tty, struct file * filp)
{
      unsigned long flags;
      struct gs_port *port;
      
      func_enter ();

      if (!tty) return;

      port = (struct gs_port *) tty->driver_data;

      if (!port) return;

      if (!port->tty) {
            /* This seems to happen when this is called from vhangup. */
            gs_dprintk (GS_DEBUG_CLOSE, "gs: Odd: port->tty is NULL\n");
            port->tty = tty;
      }

      spin_lock_irqsave(&port->driver_lock, flags);

      if (tty_hung_up_p(filp)) {
            spin_unlock_irqrestore(&port->driver_lock, flags);
            if (port->rd->hungup)
                  port->rd->hungup (port);
            func_exit ();
            return;
      }

      if ((tty->count == 1) && (port->count != 1)) {
            printk(KERN_ERR "gs: gs_close port %p: bad port count;"
                   " tty->count is 1, port count is %d\n", port, port->count);
            port->count = 1;
      }
      if (--port->count < 0) {
            printk(KERN_ERR "gs: gs_close port %p: bad port count: %d\n", port, port->count);
            port->count = 0;
      }

      if (port->count) {
            gs_dprintk(GS_DEBUG_CLOSE, "gs_close port %p: count: %d\n", port, port->count);
            spin_unlock_irqrestore(&port->driver_lock, flags);
            func_exit ();
            return;
      }
      port->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 (port->closing_wait != ASYNC_CLOSING_WAIT_NONE)
         tty_wait_until_sent(tty, port->closing_wait); */

      /*
       * At this point we stop accepting input.  To do this, we
       * disable the receive line status interrupts, and tell the
       * interrupt driver to stop checking the data ready bit in the
       * line status register.
       */

      port->rd->disable_rx_interrupts (port);
      spin_unlock_irqrestore(&port->driver_lock, flags);

      /* close has no way of returning "EINTR", so discard return value */
      if (port->closing_wait != ASYNC_CLOSING_WAIT_NONE)
            gs_wait_tx_flushed (port, port->closing_wait);

      port->flags &= ~GS_ACTIVE;

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

      tty_ldisc_flush(tty);
      tty->closing = 0;

      port->event = 0;
      port->rd->close (port);
      port->rd->shutdown_port (port);
      port->tty = NULL;

      if (port->blocked_open) {
            if (port->close_delay) {
                  spin_unlock_irqrestore(&port->driver_lock, flags);
                  msleep_interruptible(jiffies_to_msecs(port->close_delay));
                  spin_lock_irqsave(&port->driver_lock, flags);
            }
            wake_up_interruptible(&port->open_wait);
      }
      port->flags &= ~(ASYNC_NORMAL_ACTIVE|ASYNC_CLOSING | ASYNC_INITIALIZED);
      wake_up_interruptible(&port->close_wait);

      func_exit ();
}


void gs_set_termios (struct tty_struct * tty, 
                     struct ktermios * old_termios)
{
      struct gs_port *port;
      int baudrate, tmp, rv;
      struct ktermios *tiosp;

      func_enter();

      if (!tty) return;

      port = tty->driver_data;

      if (!port) return;
      if (!port->tty) {
            /* This seems to happen when this is called after gs_close. */
            gs_dprintk (GS_DEBUG_TERMIOS, "gs: Odd: port->tty is NULL\n");
            port->tty = tty;
      }


      tiosp = tty->termios;

      if (gs_debug & GS_DEBUG_TERMIOS) {
            gs_dprintk (GS_DEBUG_TERMIOS, "termios structure (%p):\n", tiosp);
      }

      if(old_termios && (gs_debug & GS_DEBUG_TERMIOS)) {
            if(tiosp->c_iflag != old_termios->c_iflag)  printk("c_iflag changed\n");
            if(tiosp->c_oflag != old_termios->c_oflag)  printk("c_oflag changed\n");
            if(tiosp->c_cflag != old_termios->c_cflag)  printk("c_cflag changed\n");
            if(tiosp->c_lflag != old_termios->c_lflag)  printk("c_lflag changed\n");
            if(tiosp->c_line  != old_termios->c_line)   printk("c_line changed\n");
            if(!memcmp(tiosp->c_cc, old_termios->c_cc, NCC)) printk("c_cc changed\n");
      }

      baudrate = tty_get_baud_rate(tty);

      if ((tiosp->c_cflag & CBAUD) == B38400) {
            if (     (port->flags & ASYNC_SPD_MASK) == ASYNC_SPD_HI)
                  baudrate = 57600;
            else if ((port->flags & ASYNC_SPD_MASK) == ASYNC_SPD_VHI)
                  baudrate = 115200;
            else if ((port->flags & ASYNC_SPD_MASK) == ASYNC_SPD_SHI)
                  baudrate = 230400;
            else if ((port->flags & ASYNC_SPD_MASK) == ASYNC_SPD_WARP)
                  baudrate = 460800;
            else if ((port->flags & ASYNC_SPD_MASK) == ASYNC_SPD_CUST)
                  baudrate = (port->baud_base / port->custom_divisor);
      }

      /* I recommend using THIS instead of the mess in termios (and
         duplicating the above code). Next we should create a clean
         interface towards this variable. If your card supports arbitrary
         baud rates, (e.g. CD1400 or 16550 based cards) then everything
         will be very easy..... */
      port->baud = baudrate;

      /* Two timer ticks seems enough to wakeup something like SLIP driver */
      /* Baudrate/10 is cps. Divide by HZ to get chars per tick. */
      tmp = (baudrate / 10 / HZ) * 2;                  

      if (tmp <                 0) tmp = 0;
      if (tmp >= SERIAL_XMIT_SIZE) tmp = SERIAL_XMIT_SIZE-1;

      port->wakeup_chars = tmp;

      /* We should really wait for the characters to be all sent before
         changing the settings. -- CAL */
      rv = gs_wait_tx_flushed (port, MAX_SCHEDULE_TIMEOUT);
      if (rv < 0) return /* rv */;

      rv = port->rd->set_real_termios(port);
      if (rv < 0) return /* rv */;

      if ((!old_termios || 
           (old_termios->c_cflag & CRTSCTS)) &&
          !(      tiosp->c_cflag & CRTSCTS)) {
            tty->stopped = 0;
            gs_start(tty);
      }

#ifdef tytso_patch_94Nov25_1726
      /* This "makes sense", Why is it commented out? */

      if (!(old_termios->c_cflag & CLOCAL) &&
          (tty->termios->c_cflag & CLOCAL))
            wake_up_interruptible(&port->gs.open_wait);
#endif

      func_exit();
      return /* 0 */;
}



/* Must be called with interrupts enabled */
int gs_init_port(struct gs_port *port)
{
      unsigned long flags;

      func_enter ();

      if (port->flags & ASYNC_INITIALIZED) {
            func_exit ();
            return 0;
      }
      if (!port->xmit_buf) {
            /* We may sleep in get_zeroed_page() */
            unsigned long tmp;

            tmp = get_zeroed_page(GFP_KERNEL);
            spin_lock_irqsave (&port->driver_lock, flags);
            if (port->xmit_buf) 
                  free_page (tmp);
            else
                  port->xmit_buf = (unsigned char *) tmp;
            spin_unlock_irqrestore(&port->driver_lock, flags);
            if (!port->xmit_buf) {
                  func_exit ();
                  return -ENOMEM;
            }
      }

      spin_lock_irqsave (&port->driver_lock, flags);
      if (port->tty) 
            clear_bit(TTY_IO_ERROR, &port->tty->flags);
      mutex_init(&port->port_write_mutex);
      port->xmit_cnt = port->xmit_head = port->xmit_tail = 0;
      spin_unlock_irqrestore(&port->driver_lock, flags);
      gs_set_termios(port->tty, NULL);
      spin_lock_irqsave (&port->driver_lock, flags);
      port->flags |= ASYNC_INITIALIZED;
      port->flags &= ~GS_TX_INTEN;

      spin_unlock_irqrestore(&port->driver_lock, flags);
      func_exit ();
      return 0;
}


int gs_setserial(struct gs_port *port, struct serial_struct __user *sp)
{
      struct serial_struct sio;

      if (copy_from_user(&sio, sp, sizeof(struct serial_struct)))
            return(-EFAULT);

      if (!capable(CAP_SYS_ADMIN)) {
            if ((sio.baud_base != port->baud_base) ||
                (sio.close_delay != port->close_delay) ||
                ((sio.flags & ~ASYNC_USR_MASK) !=
                 (port->flags & ~ASYNC_USR_MASK)))
                  return(-EPERM);
      } 

      port->flags = (port->flags & ~ASYNC_USR_MASK) |
            (sio.flags & ASYNC_USR_MASK);
  
      port->baud_base = sio.baud_base;
      port->close_delay = sio.close_delay;
      port->closing_wait = sio.closing_wait;
      port->custom_divisor = sio.custom_divisor;

      gs_set_termios (port->tty, NULL);

      return 0;
}


/*****************************************************************************/

/*
 *      Generate the serial struct info.
 */

int gs_getserial(struct gs_port *port, struct serial_struct __user *sp)
{
      struct serial_struct    sio;

      memset(&sio, 0, sizeof(struct serial_struct));
      sio.flags = port->flags;
      sio.baud_base = port->baud_base;
      sio.close_delay = port->close_delay;
      sio.closing_wait = port->closing_wait;
      sio.custom_divisor = port->custom_divisor;
      sio.hub6 = 0;

      /* If you want you can override these. */
      sio.type = PORT_UNKNOWN;
      sio.xmit_fifo_size = -1;
      sio.line = -1;
      sio.port = -1;
      sio.irq = -1;

      if (port->rd->getserial)
            port->rd->getserial (port, &sio);

      if (copy_to_user(sp, &sio, sizeof(struct serial_struct)))
            return -EFAULT;
      return 0;

}


void gs_got_break(struct gs_port *port)
{
      func_enter ();

      tty_insert_flip_char(port->tty, 0, TTY_BREAK);
      tty_schedule_flip(port->tty);
      if (port->flags & ASYNC_SAK) {
            do_SAK (port->tty);
      }

      func_exit ();
}


EXPORT_SYMBOL(gs_put_char);
EXPORT_SYMBOL(gs_write);
EXPORT_SYMBOL(gs_write_room);
EXPORT_SYMBOL(gs_chars_in_buffer);
EXPORT_SYMBOL(gs_flush_buffer);
EXPORT_SYMBOL(gs_flush_chars);
EXPORT_SYMBOL(gs_stop);
EXPORT_SYMBOL(gs_start);
EXPORT_SYMBOL(gs_hangup);
EXPORT_SYMBOL(gs_block_til_ready);
EXPORT_SYMBOL(gs_close);
EXPORT_SYMBOL(gs_set_termios);
EXPORT_SYMBOL(gs_init_port);
EXPORT_SYMBOL(gs_setserial);
EXPORT_SYMBOL(gs_getserial);
EXPORT_SYMBOL(gs_got_break);

MODULE_LICENSE("GPL");

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