sir_dev.c

h内核

/*********************************************************************
 *
 *	sir_dev.c:	irda sir network device
 * 
 *	Copyright (c) 2002 Martin Diehl
 * 
 *	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.
 *
 ********************************************************************/    

#include <linux/module.h>
#include <linux/kernel.h>
#include <linux/init.h>
#include <linux/smp_lock.h>

#include <net/irda/irda.h>
#include <net/irda/wrapper.h>
#include <net/irda/irda_device.h>

#include "sir-dev.h"

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

void sirdev_enable_rx(struct sir_dev *dev)
{
	if (unlikely(atomic_read(&dev->enable_rx)))
		return;

	/* flush rx-buffer - should also help in case of problems with echo cancelation */
	dev->rx_buff.data = dev->rx_buff.head;
	dev->rx_buff.len = 0;
	dev->rx_buff.in_frame = FALSE;
	dev->rx_buff.state = OUTSIDE_FRAME;
	atomic_set(&dev->enable_rx, 1);
}

static int sirdev_is_receiving(struct sir_dev *dev)
{
	if (!atomic_read(&dev->enable_rx))
		return 0;

	return (dev->rx_buff.state != OUTSIDE_FRAME);
}

int sirdev_set_dongle(struct sir_dev *dev, IRDA_DONGLE type)
{
	int err;

	IRDA_DEBUG(3, "%s : requesting dongle %d.\n", __FUNCTION__, type);

	err = sirdev_schedule_dongle_open(dev, type);
	if (unlikely(err))
		return err;
	down(&dev->fsm.sem);		/* block until config change completed */
	err = dev->fsm.result;
	up(&dev->fsm.sem);
	return err;
}

/* used by dongle drivers for dongle programming */

int sirdev_raw_write(struct sir_dev *dev, const char *buf, int len)
{
	unsigned long flags;
	int ret;

	if (unlikely(len > dev->tx_buff.truesize))
		return -ENOSPC;

	spin_lock_irqsave(&dev->tx_lock, flags);	/* serialize with other tx operations */
	while (dev->tx_buff.len > 0) {			/* wait until tx idle */
		spin_unlock_irqrestore(&dev->tx_lock, flags);
		set_current_state(TASK_UNINTERRUPTIBLE);
		schedule_timeout(msecs_to_jiffies(10));
		spin_lock_irqsave(&dev->tx_lock, flags);
	}

	dev->tx_buff.data = dev->tx_buff.head;
	memcpy(dev->tx_buff.data, buf, len);	
	dev->tx_buff.len = len;

	ret = dev->drv->do_write(dev, dev->tx_buff.data, dev->tx_buff.len);
	if (ret > 0) {
		IRDA_DEBUG(3, "%s(), raw-tx started\n", __FUNCTION__);

		dev->tx_buff.data += ret;
		dev->tx_buff.len -= ret;
		dev->raw_tx = 1;
		ret = len;		/* all data is going to be sent */
	}
	spin_unlock_irqrestore(&dev->tx_lock, flags);
	return ret;
}

/* seems some dongle drivers may need this */

int sirdev_raw_read(struct sir_dev *dev, char *buf, int len)
{
	int count;

	if (atomic_read(&dev->enable_rx))
		return -EIO;		/* fail if we expect irda-frames */

	count = (len < dev->rx_buff.len) ? len : dev->rx_buff.len;

	if (count > 0) {
		memcpy(buf, dev->rx_buff.data, count);
		dev->rx_buff.data += count;
		dev->rx_buff.len -= count;
	}

	/* remaining stuff gets flushed when re-enabling normal rx */

	return count;
}

int sirdev_set_dtr_rts(struct sir_dev *dev, int dtr, int rts)
{
	int ret = -ENXIO;
	if (dev->drv->set_dtr_rts != 0)
		ret =  dev->drv->set_dtr_rts(dev, dtr, rts);
	return ret;
}
	
/**********************************************************************/

/* called from client driver - likely with bh-context - to indicate
 * it made some progress with transmission. Hence we send the next
 * chunk, if any, or complete the skb otherwise
 */

void sirdev_write_complete(struct sir_dev *dev)
{
	unsigned long flags;
	struct sk_buff *skb;
	int actual = 0;
	int err;
	
	spin_lock_irqsave(&dev->tx_lock, flags);

	IRDA_DEBUG(3, "%s() - dev->tx_buff.len = %d\n",
		   __FUNCTION__, dev->tx_buff.len);

	if (likely(dev->tx_buff.len > 0))  {
		/* Write data left in transmit buffer */
		actual = dev->drv->do_write(dev, dev->tx_buff.data, dev->tx_buff.len);

		if (likely(actual>0)) {
			dev->tx_buff.data += actual;
			dev->tx_buff.len  -= actual;
		}
		else if (unlikely(actual<0)) {
			/* could be dropped later when we have tx_timeout to recover */
			ERROR("%s: drv->do_write failed (%d)\n", __FUNCTION__, actual);
			if ((skb=dev->tx_skb) != NULL) {
				dev->tx_skb = NULL;
				dev_kfree_skb_any(skb);
				dev->stats.tx_errors++;		      
				dev->stats.tx_dropped++;		      
			}
			dev->tx_buff.len = 0;
		}
		if (dev->tx_buff.len > 0)
			goto done;	/* more data to send later */
	}

	if (unlikely(dev->raw_tx != 0)) {
		/* in raw mode we are just done now after the buffer was sent
		 * completely. Since this was requested by some dongle driver
		 * running under the control of the irda-thread we must take
		 * care here not to re-enable the queue. The queue will be
		 * restarted when the irda-thread has completed the request.
		 */

		IRDA_DEBUG(3, "%s(), raw-tx done\n", __FUNCTION__);
		dev->raw_tx = 0;
		goto done;	/* no post-frame handling in raw mode */
	}

	/* we have finished now sending this skb.
	 * update statistics and free the skb.
	 * finally we check and trigger a pending speed change, if any.
	 * if not we switch to rx mode and wake the queue for further
	 * packets.
	 * note the scheduled speed request blocks until the lower
	 * client driver and the corresponding hardware has really
	 * finished sending all data (xmit fifo drained f.e.)
	 * before the speed change gets finally done and the queue
	 * re-activated.
	 */

	IRDA_DEBUG(5, "%s(), finished with frame!\n", __FUNCTION__);
		
	if ((skb=dev->tx_skb) != NULL) {
		dev->tx_skb = NULL;
		dev->stats.tx_packets++;		      
		dev->stats.tx_bytes += skb->len;
		dev_kfree_skb_any(skb);
	}

	if (unlikely(dev->new_speed > 0)) {
		IRDA_DEBUG(5, "%s(), Changing speed!\n", __FUNCTION__);
		err = sirdev_schedule_speed(dev, dev->new_speed);
		if (unlikely(err)) {
			/* should never happen
			 * forget the speed change and hope the stack recovers
			 */
			ERROR("%s - schedule speed change failed: %d\n", __FUNCTION__, err);
			netif_wake_queue(dev->netdev);
		}
		/* else: success
		 *	speed change in progress now
		 *	on completion dev->new_speed gets cleared,
		 *	rx-reenabled and the queue restarted
		 */
	}
	else {
		sirdev_enable_rx(dev);
		netif_wake_queue(dev->netdev);
	}

done:
	spin_unlock_irqrestore(&dev->tx_lock, flags);
}

/* called from client driver - likely with bh-context - to give us
 * some more received bytes. We put them into the rx-buffer,
 * normally unwrapping and building LAP-skb's (unless rx disabled)
 */

int sirdev_receive(struct sir_dev *dev, const unsigned char *cp, size_t count) 
{
	if (!dev || !dev->netdev) {
		WARNING("%s(), not ready yet!\n", __FUNCTION__);
		return -1;
	}

	if (!dev->irlap) {
		WARNING("%s - too early: %p / %zd!\n",
			__FUNCTION__, cp, count);
		return -1;
	}

	if (cp==NULL) {
		/* error already at lower level receive
		 * just update stats and set media busy
		 */
		irda_device_set_media_busy(dev->netdev, TRUE);
		dev->stats.rx_dropped++;
		IRDA_DEBUG(0, "%s; rx-drop: %zd\n", __FUNCTION__, count);
		return 0;
	}

	/* Read the characters into the buffer */
	if (likely(atomic_read(&dev->enable_rx))) {
		while (count--)
			/* Unwrap and destuff one byte */
			async_unwrap_char(dev->netdev, &dev->stats, 
					  &dev->rx_buff, *cp++);
	} else {
		while (count--) {
			/* rx not enabled: save the raw bytes and never
			 * trigger any netif_rx. The received bytes are flushed
			 * later when we re-enable rx but might be read meanwhile
			 * by the dongle driver.
			 */
			dev->rx_buff.data[dev->rx_buff.len++] = *cp++;

			/* What should we do when the buffer is full? */
			if (unlikely(dev->rx_buff.len == dev->rx_buff.truesize))
				dev->rx_buff.len = 0;
		}
	}

	return 0;
}

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

/* callbacks from network layer */

static struct net_device_stats *sirdev_get_stats(struct net_device *ndev)
{
	struct sir_dev *dev = ndev->priv;

	return (dev) ? &dev->stats : NULL;
}

static int sirdev_hard_xmit(struct sk_buff *skb, struct net_device *ndev)
{
	struct sir_dev *dev = ndev->priv;
	unsigned long flags;
	int actual = 0;
	int err;
	s32 speed;

	ASSERT(dev != NULL, return 0;);

	netif_stop_queue(ndev);

	IRDA_DEBUG(3, "%s(), skb->len = %d\n", __FUNCTION__, skb->len);

	speed = irda_get_next_speed(skb);
	if ((speed != dev->speed) && (speed != -1)) {
		if (!skb->len) {
			err = sirdev_schedule_speed(dev, speed);
			if (unlikely(err == -EWOULDBLOCK)) {
				/* Failed to initiate the speed change, likely the fsm
				 * is still busy (pretty unlikely, but...)
				 * We refuse to accept the skb and return with the queue
				 * stopped so the network layer will retry after the
				 * fsm completes and wakes the queue.
				 */
				 return 1;
			}
			else if (unlikely(err)) {
				/* other fatal error - forget the speed change and
				 * hope the stack will recover somehow
				 */
				 netif_start_queue(ndev);
			}
			/* else: success
			 *	speed change in progress now
			 *	on completion the queue gets restarted
			 */

			dev_kfree_skb_any(skb);
			return 0;
		} else
			dev->new_speed = speed;
	}

	/* Init tx buffer*/
	dev->tx_buff.data = dev->tx_buff.head;