ircomm_tty.c

linux-2.6.15.6

		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) {
		IRDA_DEBUG(2, 
		      "%s(), returning after block_til_ready with %d\n", __FUNCTION__ ,
		      ret);

		return ret;
	}
	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, "%s()\n", __FUNCTION__ );

	if (!tty)
		return;

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

	spin_lock_irqsave(&self->spinlock, flags);

	if (tty_hung_up_p(filp)) {
		spin_unlock_irqrestore(&self->spinlock, flags);

		IRDA_DEBUG(0, "%s(), returning 1\n", __FUNCTION__ );
		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, "%s(), bad serial port count; "
			   "tty->count is 1, state->count is %d\n", __FUNCTION__ , 
			   self->open_count);
		self->open_count = 1;
	}

	if (--self->open_count < 0) {
		IRDA_ERROR("%s(), bad serial port count for ttys%d: %d\n",
			   __FUNCTION__, self->line, self->open_count);
		self->open_count = 0;
	}
	if (self->open_count) {
		spin_unlock_irqrestore(&self->spinlock, flags);

		IRDA_DEBUG(0, "%s(), open count > 0\n", __FUNCTION__ );
		return;
	}

	/* Hum... Should be test_and_set_bit ??? - Jean II */
	set_bit(ASYNC_B_CLOSING, &self->flags);

	/* We need to unlock here (we were unlocking at the end of this
	 * function), because tty_wait_until_sent() may schedule.
	 * I don't know if the rest should be protected somehow,
	 * so someone should check. - Jean II */
	spin_unlock_irqrestore(&self->spinlock, flags);

	/*
	 * 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 = NULL;

	if (self->blocked_open) {
		if (self->close_delay)
			schedule_timeout_interruptible(self->close_delay);
		wake_up_interruptible(&self->open_wait);
	}

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

/*
 * 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;

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

	/* 
	 * Let do_softint() do this to avoid race condition with 
	 * do_softint() ;-) 
	 */
	schedule_work(&self->tqueue);
}

/*
 * 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, "%s()\n", __FUNCTION__ );

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

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

	/* Unlink control buffer */
	spin_lock_irqsave(&self->spinlock, flags);

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

	spin_unlock_irqrestore(&self->spinlock, flags);

	/* Flush control buffer if any */
	if(ctrl_skb) {
		if(self->flow == FLOW_START)
			ircomm_control_request(self->ircomm, ctrl_skb);
		/* Drop reference count - see ircomm_ttp_data_request(). */
		dev_kfree_skb(ctrl_skb);
	}

	if (tty->hw_stopped)
		return;

	/* Unlink transmit buffer */
	spin_lock_irqsave(&self->spinlock, flags);
	
	skb = self->tx_skb;
	self->tx_skb = NULL;

	spin_unlock_irqrestore(&self->spinlock, flags);

	/* Flush transmit buffer if any */
	if (skb) {
		ircomm_tty_do_event(self, IRCOMM_TTY_DATA_REQUEST, skb, NULL);
		/* Drop reference count - see ircomm_ttp_data_request(). */
		dev_kfree_skb(skb);
	}
		
	/* 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, 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,
			    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, "%s(), count=%d, hw_stopped=%d\n", __FUNCTION__ , count,
		   tty->hw_stopped);

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

	/* We may receive packets from the TTY even before we have finished
	 * our setup. Not cool.
	 * The problem is that we don't know the final header and data size
	 * to create the proper skb, so any skb we would create would have
	 * bogus header and data size, so need care.
	 * We use a bogus header size to safely detect this condition.
	 * Another problem is that hw_stopped was set to 0 way before it
	 * should be, so we would drop this skb. It should now be fixed.
	 * One option is to not accept data until we are properly setup.
	 * But, I suspect that when it happens, the ppp line discipline
	 * just "drops" the data, which might screw up connect scripts.
	 * The second option is to create a "safe skb", with large header
	 * and small size (see ircomm_tty_open() for values).
	 * We just need to make sure that when the real values get filled,
	 * we don't mess up the original "safe skb" (see tx_data_size).
	 * Jean II */
	if (self->max_header_size == IRCOMM_TTY_HDR_UNINITIALISED) {
		IRDA_DEBUG(1, "%s() : not initialised\n", __FUNCTION__);
#ifdef IRCOMM_NO_TX_BEFORE_INIT
		/* We didn't consume anything, TTY will retry */
		return 0;
#endif
	}

	if (count < 1)
		return 0;

	/* Protect our manipulation of self->tx_skb and related */
	spin_lock_irqsave(&self->spinlock, flags);

	/* 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
			 * Note : use tx_data_size, because max_data_size
			 * may have changed and we don't want to overwrite
			 * the skb. - Jean II
			 */
			if ((tailroom = (self->tx_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) {
				spin_unlock_irqrestore(&self->spinlock, flags);
				return -ENOBUFS;
			}
			skb_reserve(skb, self->max_header_size);
			self->tx_skb = skb;
			/* Remember skb size because max_data_size may
			 * change later on - Jean II */
			self->tx_data_size = self->max_data_size;
		}

		/* Copy data */
		memcpy(skb_put(skb,size), buf + len, size);

		count -= size;
		len += size;
	}

	spin_unlock_irqrestore(&self->spinlock, 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.  
	 */
	schedule_work(&self->tqueue);
	
	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;

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

#ifdef IRCOMM_NO_TX_BEFORE_INIT
	/* max_header_size tells us if the channel is initialised or not. */
	if (self->max_header_size == IRCOMM_TTY_HDR_UNINITIALISED)
		/* Don't bother us yet */
		return 0;
#endif

	/* Check if we are allowed to transmit any data.
	 * hw_stopped is the regular flow control.
	 * Jean II */
	if (tty->hw_stopped)
		ret = 0;
	else {
		spin_lock_irqsave(&self->spinlock, flags);
		if (self->tx_skb)
			ret = self->tx_data_size - self->tx_skb->len;
		else
			ret = self->max_data_size;
		spin_unlock_irqrestore(&self->spinlock, flags);
	}
	IRDA_DEBUG(2, "%s(), ret=%d\n", __FUNCTION__ , 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;
	unsigned long flags;
	
	IRDA_DEBUG(2, "%s()\n", __FUNCTION__ );

	IRDA_ASSERT(self != NULL, return;);
	IRDA_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));

	spin_lock_irqsave(&self->spinlock, flags);
	while (self->tx_skb && self->tx_skb->len) {
		spin_unlock_irqrestore(&self->spinlock, flags);
		schedule_timeout_interruptible(poll_time);
		spin_lock_irqsave(&self->spinlock, flags);
		if (signal_pending(current))
			break;
		if (timeout && time_after(jiffies, orig_jiffies + timeout))
			break;
	}
	spin_unlock_irqrestore(&self->spinlock, flags);
	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, "%s()\n", __FUNCTION__ );

	IRDA_ASSERT(self != NULL, return;);
	IRDA_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, "%s()\n", __FUNCTION__ );

	IRDA_ASSERT(self != NULL, return;);
	IRDA_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, "%s(), FLOW_START\n", __FUNCTION__ );
	}
        ircomm_flow_request(self->ircomm, FLOW_START);
}