sdla_x25.c

powerpc内核mpc8241linux系统下net驱动程序

 */
static int del_if (wan_device_t* wandev, struct device* dev)
{
	if (dev->priv)
	{
		kfree(dev->priv);
		dev->priv = NULL;
	}
	return 0;
}

/****** WANPIPE-specific entry points ***************************************/

/*============================================================================
 * Execute adapter interface command.
 */

static int wpx_exec (struct sdla* card, void* u_cmd, void* u_data)
{
	TX25Mbox* mbox = card->mbox;
	int retry = MAX_CMD_RETRY;
	int err, len;
	TX25Cmd cmd;

	if(copy_from_user((void*)&cmd, u_cmd, sizeof(cmd)))
		return -EFAULT;
		
	/* execute command */

	do
	{
		memcpy(&mbox->cmd, &cmd, sizeof(cmd));
		if (cmd.length)
		{
			if(copy_from_user((void*)&mbox->data, u_data, cmd.length))
				return-EFAULT;
		}
		if (sdla_exec(mbox))
			err = mbox->cmd.result
		;
		else return -EIO;
	}
	while (err && retry-- && x25_error(card, err, cmd.command, cmd.lcn));

	/* return result */
	if(copy_to_user(u_cmd, (void*)&mbox->cmd, sizeof(TX25Cmd)))
		return -EFAULT;
	len = mbox->cmd.length;
	if (len && u_data && copy_to_user(u_data, (void*)&mbox->data, len))
		return -EFAULT;
	return 0;
}

/****** Network Device Interface ********************************************/

/*============================================================================
 * Initialize Linux network interface.
 *
 * This routine is called only once for each interface, during Linux network
 * interface registration.  Returning anything but zero will fail interface
 * registration.
 */
static int if_init (struct device* dev)
{
	x25_channel_t* chan = dev->priv;
	sdla_t* card = chan->card;
	wan_device_t* wandev = &card->wandev;

	/* Initialize device driver entry points */
	dev->open		= &if_open;
	dev->stop		= &if_close;
	dev->hard_header	= &if_header;
	dev->rebuild_header	= &if_rebuild_hdr;
	dev->hard_start_xmit	= &if_send;
	dev->get_stats		= &if_stats;

	/* Initialize media-specific parameters */
	dev->type		= 30;		/* ARP h/w type */
	dev->mtu		= X25_CHAN_MTU;
	dev->hard_header_len	= X25_HRDHDR_SZ; /* media header length */
	dev->addr_len		= 2;		/* hardware address length */
	if (!chan->svc)
		*(unsigned short*)dev->dev_addr = htons(chan->lcn);

	/* Initialize hardware parameters (just for reference) */
	dev->irq	= wandev->irq;
	dev->dma	= wandev->dma;
	dev->base_addr	= wandev->ioport;
	dev->mem_start	= (unsigned long)wandev->maddr;
	dev->mem_end	= dev->mem_end + wandev->msize - 1;

        /* Set transmit buffer queue length */
        dev->tx_queue_len = 10;

	/* Initialize socket buffers */
	
	dev_init_buffers(dev);
	set_chan_state(dev, WAN_DISCONNECTED);
	return 0;
}

/*============================================================================
 * Open network interface.
 * o prevent module from unloading by incrementing use count
 * o if link is disconnected then initiate connection
 *
 * Return 0 if O.k. or errno.
 */
static int if_open (struct device* dev)
{
	x25_channel_t* chan = dev->priv;
	sdla_t* card = chan->card;

	if (dev->start)
		return -EBUSY;		/* only one open is allowed */
	
	if (test_and_set_bit(0, (void*)&card->wandev.critical))
		return -EAGAIN;

	dev->interrupt = 0;
	dev->tbusy = 0;
	dev->start = 1;
	wanpipe_open(card);

	/* If this is the first open, initiate physical connection */
	if (card->open_cnt == 1)
		connect(card);
	card->wandev.critical = 0;
	return 0;
}

/*============================================================================
 * Close network interface.
 * o reset flags.
 * o if there's no more open channels then disconnect physical link.
 */
static int if_close (struct device* dev)
{
	x25_channel_t* chan = dev->priv;
	sdla_t* card = chan->card;

	if (test_and_set_bit(0, (void*)&card->wandev.critical))
		return -EAGAIN;

	dev->start = 0;
	if ((chan->state == WAN_CONNECTED) || (chan->state == WAN_CONNECTING))
		chan_disc(dev);
		
	wanpipe_close(card);

	/* If this is the last close, disconnect physical link */
	if (!card->open_cnt)
		disconnect(card);
		
	card->wandev.critical = 0;
	return 0;
}

/*============================================================================
 * Build media header.
 * o encapsulate packet according to encapsulation type.
 *
 * The trick here is to put packet type (Ethertype) into 'protocol' field of
 * the socket buffer, so that we don't forget it.  If encapsulation fails,
 * set skb->protocol to 0 and discard packet later.
 *
 * Return:	media header length.
 */
static int if_header (struct sk_buff* skb, struct device* dev,
	unsigned short type, void* daddr, void* saddr, unsigned len)
{
	x25_channel_t* chan = dev->priv;
	int hdr_len = dev->hard_header_len;

	skb->protocol = type;
	if (!chan->protocol)
	{
		hdr_len = wanrouter_encapsulate(skb, dev);
		if (hdr_len < 0)
		{
			hdr_len = 0;
			skb->protocol = 0;
		}
	}
	return hdr_len;
}

/*============================================================================
 * Re-build media header.
 *
 * Return:	1	physical address resolved.
 *		0	physical address not resolved
 */
 
static int if_rebuild_hdr (struct sk_buff* skb)
{
	struct device *dev=skb->dev;
	x25_channel_t* chan = dev->priv;
	sdla_t* card = chan->card;

	printk(KERN_INFO "%s: rebuild_header() called for interface %s!\n",
		card->devname, dev->name);
	return 1;
}

/*============================================================================
 * Send a packet on a network interface.
 * o set tbusy flag (marks start of the transmission).
 * o check link state. If link is not up, then drop the packet.
 * o check channel status. If it's down then initiate a call.
 * o pass a packet to corresponding WAN device.
 * o free socket buffer
 *
 * Return:	0	complete (socket buffer must be freed)
 *		non-0	packet may be re-transmitted (tbusy must be set)
 *
 * Notes:
 * 1. This routine is called either by the protocol stack or by the "net
 *    bottom half" (with interrupts enabled).
 * 2. Setting tbusy flag will inhibit further transmit requests from the
 *    protocol stack and can be used for flow control with protocol layer.
 */

static int if_send (struct sk_buff* skb, struct device* dev)
{
	x25_channel_t* chan = dev->priv;
	sdla_t* card = chan->card;
	struct device *dev2;
	TX25Status* status = card->flags;
	unsigned long host_cpu_flags;

	if (dev->tbusy)
	{
		++chan->ifstats.rx_dropped;	
		if ((jiffies - chan->tick_counter) < (5*HZ))
		{
			return dev->tbusy;
		}
		printk(KERN_INFO "%s: Transmit time out %s!\n",
			card->devname, dev->name)
		;
		for( dev2 = card->wandev.dev; dev2; dev2 = dev2->slave)
		{
	        	dev2->tbusy = 0;
		}
	}
	chan->tick_counter = jiffies;

	disable_irq(card->hw.irq);
	++card->irq_dis_if_send_count;

	if (test_and_set_bit(0, (void*)&card->wandev.critical)) 
	{
		printk(KERN_INFO "Hit critical in if_send()!\n");
		if (card->wandev.critical == CRITICAL_IN_ISR) 
		{
			card->wandev.enable_tx_int = 1;
			dev->tbusy = 1;
			
			save_flags(host_cpu_flags);
                        cli();
                        if ((!(--card->irq_dis_if_send_count)) &&
                                        (!card->irq_dis_poll_count))
                                enable_irq(card->hw.irq);
                        restore_flags(host_cpu_flags);
			
			return dev->tbusy;
		}
		dev_kfree_skb(skb);
		
		save_flags(host_cpu_flags);
                cli();
                if ((!(--card->irq_dis_if_send_count)) &&
                                         (!card->irq_dis_poll_count))
                        enable_irq(card->hw.irq);
                restore_flags(host_cpu_flags);

		return dev->tbusy;
	}

	/* Below is only until we have per-channel IPX going.... */
	if(!(chan->svc))
		chan->protocol = skb->protocol;

	if (card->wandev.state != WAN_CONNECTED)
		++chan->ifstats.tx_dropped;

	/* Below is only until we have per-channel IPX going.... */
	else if ( (chan->svc) && (chan->protocol && (chan->protocol != skb->protocol)))
	{
		printk(KERN_INFO
			"%s: unsupported Ethertype 0x%04X on interface %s!\n",
			card->devname, skb->protocol, dev->name);
		++chan->ifstats.tx_errors;
	}
	else switch (chan->state)
	{
		case WAN_DISCONNECTED:
			/* Try to establish connection. If succeded, then start
			 * transmission, else drop a packet.
			 */
			if (chan_connect(dev) != 0)
			{
				++chan->ifstats.tx_dropped;
				++card->wandev.stats.tx_dropped;
				break;
			}
			/* fall through */

		case WAN_CONNECTED:
			if( skb->protocol == ETH_P_IPX ) 
			{
				if(card->wandev.enable_IPX) 
				{
					switch_net_numbers( skb->data, 
						card->wandev.network_number, 0);
				}
				else 
				{
					++card->wandev.stats.tx_dropped;
					++chan->ifstats.tx_dropped;
					goto tx_done;
				}
			}
			dev->trans_start = jiffies;
			if(chan_send(dev, skb))
			{
				dev->tbusy = 1;
				status->imask |= 0x2;
			}
			break;

		default:
			++chan->ifstats.tx_dropped;	
			++card->wandev.stats.tx_dropped;
	}
tx_done:
	if (!dev->tbusy)
		dev_kfree_skb(skb);

	card->wandev.critical = 0;
	save_flags(host_cpu_flags);
        cli();
        if ((!(--card->irq_dis_if_send_count)) && (!card->irq_dis_poll_count))
                enable_irq(card->hw.irq);
        restore_flags(host_cpu_flags);
	return dev->tbusy;
}

/*============================================================================
 * Get Ethernet-style interface statistics.
 * Return a pointer to struct net_device_stats
 */
 
static struct net_device_stats* if_stats (struct device* dev)
{
	x25_channel_t* chan = dev->priv;
	if(chan==NULL)
		return NULL;
	return &chan->ifstats;
}

/****** Interrupt Handlers **************************************************/

/*============================================================================
 * X.25 Interrupt Service Routine.
 */
 
static void wpx_isr (sdla_t* card)
{
	TX25Status* status = card->flags;
	struct device *dev;
	unsigned long host_cpu_flags;

	card->in_isr = 1;
	card->buff_int_mode_unbusy = 0;

	if (test_and_set_bit(0, (void*)&card->wandev.critical)) 
	{

 		printk(KERN_INFO "wpx_isr: %s, wandev.critical set to 0x%02X, int type = 0x%02X\n", card->devname, card->wandev.critical, status->iflags);
		card->in_isr = 0;
		return;
	}

	/* For all interrupts set the critical flag to CRITICAL_RX_INTR.
         * If the if_send routine is called with this flag set it will set
         * the enable transmit flag to 1. (for a delayed interrupt)
         */
	card->wandev.critical = CRITICAL_IN_ISR;

	switch (status->iflags)
	{
		case 0x01:		/* receive interrupt */
			rx_intr(card);
			break;

		case 0x02:		/* transmit interrupt */
			tx_intr(card);
			card->buff_int_mode_unbusy = 1;
			status->imask &= ~0x2;
			break;

		case 0x04:		/* modem status interrupt */
			status_intr(card);
			break;

		case 0x10:		/* network event interrupt */
			event_intr(card);
			break;

		default:		/* unwanted interrupt */
			spur_intr(card);
	}
	card->wandev.critical = CRITICAL_INTR_HANDLED;
	if( card->wandev.enable_tx_int)
	{
		card->wandev.enable_tx_int = 0;
		status->imask |= 0x2;
	}
	save_flags(host_cpu_flags);
	cli();
	card->in_isr = 0;
	status->iflags = 0;	/* clear interrupt condition */
	card->wandev.critical = 0;
	restore_flags(host_cpu_flags);

	if(card->buff_int_mode_unbusy)
	{
		for(dev = card->wandev.dev; dev; dev = dev->slave)
		{
			if(((x25_channel_t*)dev->priv)->devtint)
			{
				mark_bh(NET_BH);
				return;
			}	
		}
	}
}

/*============================================================================
 * Receive interrupt handler.
 * This routine handles fragmented IP packets using M-bit according to the
 * RFC1356.
 * o map ligical channel number to network interface.
 * o allocate socket buffer or append received packet to the existing one.
 * o if M-bit is reset (i.e. it's the last packet in a sequence) then 
 *   decapsulate packet and pass socket buffer to the protocol stack.
 *
 * Notes:
 * 1. When allocating a socket buffer, if M-bit is set then more data is
 *    comming and we have to allocate buffer for the maximum IP packet size
 *    expected on this channel.
 * 2. If something goes wrong and X.25 packet has to be dropped (e.g. no
 *    socket buffers available) the whole packet sequence must be discarded.
 */

static void rx_intr (sdla_t* card)
{
	TX25Mbox* rxmb = card->rxmb;
	unsigned lcn = rxmb->cmd.lcn;		/* logical channel number */
	unsigned len = rxmb->cmd.length;	/* packet length */
	unsigned qdm = rxmb->cmd.qdm;		/* Q,D and M bits */
	wan_device_t* wandev = &card->wandev;
	struct device* dev = get_dev_by_lcn(wandev, lcn);
	x25_channel_t* chan;
	struct sk_buff* skb;
	void* bufptr;

	if (dev == NULL)
	{