mkiss.c

powerpc内核mpc8241linux系统下net驱动程序

		actual = ax->mkiss->tty->driver.write(ax->mkiss->tty, 0, ax->mkiss->xbuff, count);
		ax->tx_packets++;
		ax->mkiss->dev->trans_start = jiffies;
		ax->mkiss->xleft = count - actual;
		ax->mkiss->xhead = ax->mkiss->xbuff + actual;
	}
}

/*
 * Called by the driver when there's room for more data.  If we have
 * more packets to send, we send them here.
 */
static void ax25_write_wakeup(struct tty_struct *tty)
{
	int actual;
	struct ax_disp *ax = (struct ax_disp *)tty->disc_data;
	struct mkiss_channel *mkiss;

	/* First make sure we're connected. */
	if (ax == NULL || ax->magic != AX25_MAGIC || !ax->dev->start)
		return;
	if (ax->xleft <= 0)  {
		/* Now serial buffer is almost free & we can start
		 * transmission of another packet
		 */
		tty->flags &= ~(1 << TTY_DO_WRITE_WAKEUP);

		if (ax->mkiss != NULL) {
			mkiss= ax->mkiss->tty->driver_data;
	        	if (mkiss->magic  == MKISS_DRIVER_MAGIC)
				ax_unlock(ax->mkiss);
	        }

		ax_unlock(ax);
		mark_bh(NET_BH);
		return;
	}

	actual = tty->driver.write(tty, 0, ax->xhead, ax->xleft);
	ax->xleft -= actual;
	ax->xhead += actual;
}

/* Encapsulate an AX.25 packet and kick it into a TTY queue. */
static int ax_xmit(struct sk_buff *skb, struct device *dev)
{
	struct ax_disp *ax = (struct ax_disp*)dev->priv;
	struct mkiss_channel *mkiss = ax->tty->driver_data;
	struct ax_disp *tmp_ax;

	tmp_ax = NULL;

	if (mkiss->magic  == MKISS_DRIVER_MAGIC) {
		if (skb->data[0] < 0x10)
			skb->data[0] = skb->data[0] + 0x10;
		tmp_ax = ax->mkiss;
	}

	if (!dev->start)  {
		printk(KERN_ERR "mkiss: %s: xmit call when iface is down\n", dev->name);
		return 1;
	}

	if (tmp_ax != NULL)
		if (tmp_ax->dev->tbusy)
			return 1;

	if (tmp_ax != NULL)
		if (dev->tbusy) {
			printk(KERN_ERR "mkiss: dev busy while serial dev is free\n");
			ax_unlock(ax);
	        }

	if (dev->tbusy) {
		/*
		 * May be we must check transmitter timeout here ?
		 *      14 Oct 1994 Dmitry Gorodchanin.
		 */
		if (jiffies - dev->trans_start  < 20 * HZ) {
			/* 20 sec timeout not reached */
			return 1;
		}

		printk(KERN_ERR "mkiss: %s: transmit timed out, %s?\n", dev->name,
		       (ax->tty->driver.chars_in_buffer(ax->tty) || ax->xleft) ?
		       "bad line quality" : "driver error");

		ax->xleft = 0;
		ax->tty->flags &= ~(1 << TTY_DO_WRITE_WAKEUP);
		ax_unlock(ax);
	}

	/* We were not busy, so we are now... :-) */
	if (skb != NULL) {
		ax_lock(ax);
		if (tmp_ax != NULL)
			ax_lock(tmp_ax);
		ax_encaps(ax, skb->data, skb->len);
		kfree_skb(skb);
	}

	return 0;
}

#if defined(CONFIG_AX25) || defined(CONFIG_AX25_MODULE)

/* Return the frame type ID */
static int ax_header(struct sk_buff *skb, struct device *dev, unsigned short type,
	  void *daddr, void *saddr, unsigned len)
{
#ifdef CONFIG_INET
	if (type != htons(ETH_P_AX25))
		return ax25_encapsulate(skb, dev, type, daddr, saddr, len);
#endif
	return 0;
}


static int ax_rebuild_header(struct sk_buff *skb)
{
#ifdef CONFIG_INET
	return ax25_rebuild_header(skb);
#else
	return 0;
#endif
}

#endif	/* CONFIG_{AX25,AX25_MODULE} */

/* Open the low-level part of the AX25 channel. Easy! */
static int ax_open(struct device *dev)
{
	struct ax_disp *ax = (struct ax_disp*)dev->priv;
	unsigned long len;

	if (ax->tty == NULL)
		return -ENODEV;

	/*
	 * Allocate the frame buffers:
	 *
	 * rbuff	Receive buffer.
	 * xbuff	Transmit buffer.
	 * cbuff        Temporary compression buffer.
	 */
	len = dev->mtu * 2;

	/*
	 * allow for arrival of larger UDP packets, even if we say not to
	 * also fixes a bug in which SunOS sends 512-byte packets even with
	 * an MSS of 128
	 */
	if (len < 576 * 2)
		len = 576 * 2;

	if ((ax->rbuff = kmalloc(len + 4, GFP_KERNEL)) == NULL)
		goto norbuff;

	if ((ax->xbuff = kmalloc(len + 4, GFP_KERNEL)) == NULL)
		goto noxbuff;

	ax->mtu	     = dev->mtu + 73;
	ax->buffsize = len;
	ax->rcount   = 0;
	ax->xleft    = 0;

	ax->flags   &= (1 << AXF_INUSE);      /* Clear ESCAPE & ERROR flags */
	dev->tbusy  = 0;
	dev->start  = 1;

	return 0;

	/* Cleanup */
	kfree(ax->xbuff);

noxbuff:
	kfree(ax->rbuff);

norbuff:
	return -ENOMEM;
}


/* Close the low-level part of the AX25 channel. Easy! */
static int ax_close(struct device *dev)
{
	struct ax_disp *ax = (struct ax_disp*)dev->priv;

	if (ax->tty == NULL)
		return -EBUSY;

	ax->tty->flags &= ~(1 << TTY_DO_WRITE_WAKEUP);

	dev->tbusy = 1;
	dev->start = 0;

	return 0;
}

static int ax25_receive_room(struct tty_struct *tty)
{
	return 65536;  /* We can handle an infinite amount of data. :-) */
}

/*
 * Handle the 'receiver data ready' interrupt.
 * This function is called by the 'tty_io' module in the kernel when
 * a block of data has been received, which can now be decapsulated
 * and sent on to the AX.25 layer for further processing.
 */
static void ax25_receive_buf(struct tty_struct *tty, const unsigned char *cp, char *fp, int count)
{
	struct ax_disp *ax = (struct ax_disp *)tty->disc_data;

	if (ax == NULL || ax->magic != AX25_MAGIC || !ax->dev->start)
		return;

	/*
	 * Argh! mtu change time! - costs us the packet part received
	 * at the change
	 */
	if (ax->mtu != ax->dev->mtu + 73)
		ax_changedmtu(ax);

	/* Read the characters out of the buffer */
	while (count--) {
		if (fp != NULL && *fp++) {
			if (!test_and_set_bit(AXF_ERROR, &ax->flags))
				ax->rx_errors++;
			cp++;
			continue;
		}

		kiss_unesc(ax, *cp++);
	}
}

static int ax25_open(struct tty_struct *tty)
{
	struct ax_disp *ax = (struct ax_disp *)tty->disc_data;
	struct ax_disp *tmp_ax;
	struct mkiss_channel *mkiss;
	int err, cnt;

	/* First make sure we're not already connected. */
	if (ax && ax->magic == AX25_MAGIC)
		return -EEXIST;

	/* OK.  Find a free AX25 channel to use. */
	if ((ax = ax_alloc()) == NULL)
		return -ENFILE;

	ax->tty = tty;
	tty->disc_data = ax;

	ax->mkiss = NULL;
	tmp_ax    = NULL;

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

	/* Restore default settings */
	ax->dev->type = ARPHRD_AX25;

	/* Perform the low-level AX25 initialization. */
	if ((err = ax_open(ax->dev)))
		return err;

	mkiss= ax->tty->driver_data;

	if (mkiss->magic  == MKISS_DRIVER_MAGIC) {
		for (cnt = 1; cnt < ax25_maxdev; cnt++) {
			if (ax25_ctrls[cnt]) {
				if (ax25_ctrls[cnt]->dev.start) {
					if (ax == &ax25_ctrls[cnt]->ctrl) {
						cnt--;
						tmp_ax = &ax25_ctrls[cnt]->ctrl;
						break;
					}
				}
			}
		}
	}

	if (tmp_ax != NULL) {
		ax->mkiss     = tmp_ax;
		tmp_ax->mkiss = ax;
	}

	MOD_INC_USE_COUNT;

	/* Done.  We have linked the TTY line to a channel. */
	return ax->dev->base_addr;
}

static void ax25_close(struct tty_struct *tty)
{
	struct ax_disp *ax = (struct ax_disp *)tty->disc_data;
	int mkiss ;

	/* First make sure we're connected. */
	if (ax == NULL || ax->magic != AX25_MAGIC)
		return;

	mkiss = ax->mode;

	dev_close(ax->dev);

	tty->disc_data = 0;
	ax->tty        = NULL;

	/* VSV = very important to remove timers */
	ax_free(ax);
	unregister_netdev(ax->dev);

	MOD_DEC_USE_COUNT;
}


static struct net_device_stats *ax_get_stats(struct device *dev)
{
	static struct net_device_stats stats;
	struct ax_disp *ax = (struct ax_disp*)dev->priv;

	memset(&stats, 0, sizeof(struct net_device_stats));

	stats.rx_packets     = ax->rx_packets;
	stats.tx_packets     = ax->tx_packets;
	stats.rx_dropped     = ax->rx_dropped;
	stats.tx_dropped     = ax->tx_dropped;
	stats.tx_errors      = ax->tx_errors;
	stats.rx_errors      = ax->rx_errors;
	stats.rx_over_errors = ax->rx_over_errors;

	return &stats;
}


/************************************************************************
 *			   STANDARD ENCAPSULATION	        	 *
 ************************************************************************/

int kiss_esc(unsigned char *s, unsigned char *d, int len)
{
	unsigned char *ptr = d;
	unsigned char c;

	/*
	 * Send an initial END character to flush out any
	 * data that may have accumulated in the receiver
	 * due to line noise.
	 */

	*ptr++ = END;

	while (len-- > 0) {
		switch (c = *s++) {
			case END:
				*ptr++ = ESC;
				*ptr++ = ESC_END;
				break;
			case ESC:
				*ptr++ = ESC;
				*ptr++ = ESC_ESC;
				break;
			default:
				*ptr++ = c;
				break;
		}
	}

	*ptr++ = END;

	return ptr - d;
}

/*
 * MW:
 * OK its ugly, but tell me a better solution without copying the
 * packet to a temporary buffer :-)
 */
static int kiss_esc_crc(unsigned char *s, unsigned char *d, unsigned short crc, int len)
{
	unsigned char *ptr = d;
	unsigned char c;

	*ptr++ = END;
	while (len > 0) {
		if (len > 2) 
			c = *s++;
		else if (len > 1)
			c = crc >> 8;
		else if (len > 0)
			c = crc & 0xff;

		len--;

		switch (c) {
                        case END:
                                *ptr++ = ESC;
                                *ptr++ = ESC_END;
                                break;
                        case ESC:
                                *ptr++ = ESC;
                                *ptr++ = ESC_ESC;
                                break;
                        default:
                                *ptr++ = c;
                                break;
		}
	}
	*ptr++ = END;
	return ptr - d;		
}

static void kiss_unesc(struct ax_disp *ax, unsigned char s)