void alloc586(struct net_device *dev)
{
	struct priv *p = (struct priv *) dev->priv;

	elmc_id_reset586();
	DELAY(2);

	p->scp = (struct scp_struct *) (p->base + SCP_DEFAULT_ADDRESS);
	p->scb = (struct scb_struct *) bus_to_virt(dev->mem_start);
	p->iscp = (struct iscp_struct *) ((char *) p->scp - sizeof(struct iscp_struct));

	memset((char *) p->iscp, 0, sizeof(struct iscp_struct));
	memset((char *) p->scp, 0, sizeof(struct scp_struct));

	p->scp->iscp = make24(p->iscp);
	p->scp->sysbus = SYSBUSVAL;
	p->iscp->scb_offset = make16(p->scb);

	p->iscp->busy = 1;
	elmc_id_reset586();
	elmc_id_attn586();

	DELAY(2);

	if (p->iscp->busy) {
		printk(KERN_ERR "%s: Init-Problems (alloc).\n", dev->name);
	}
	memset((char *) p->scb, 0, sizeof(struct scb_struct));
}

static int elmc_close(struct net_device *dev)
{
	netif_stop_queue(dev);
	elmc_id_reset586();	/* the hard way to stop the receiver */
	free_irq(dev->irq, dev);
	return 0;
}

void cleanup_module(void)
{
	int this_dev;
	for(this_dev=0; this_dev<MAX_3C523_CARDS; this_dev++) {

		struct net_device *dev = &dev_elmc[this_dev];
		if(dev->priv) {
			/* shutdown interrupts on the card */
			elmc_id_reset586();
			if (dev->irq != 0) {
				/* this should be done by close, but if we failed to
				   initialize properly something may have gotten hosed. */
				free_irq(dev->irq, dev);
				dev->irq = 0;
			}
			if (dev->base_addr != 0) {
				release_region(dev->base_addr, ELMC_IO_EXTENT);
				dev->base_addr = 0;
			}
			irq[this_dev] = 0;
			io[this_dev] = 0;
			unregister_netdev(dev);

			mca_set_adapter_procfn(((struct priv *) (dev->priv))->slot,
			       NULL, NULL);

			kfree(dev->priv);
			dev->priv = NULL;
		}
	}
}

static int elmc_open(struct net_device *dev)
{
	int ret;

	elmc_id_attn586();	/* disable interrupts */

	ret = request_irq(dev->irq, &elmc_interrupt, SA_SHIRQ | SA_SAMPLE_RANDOM,
			  dev->name, dev);
	if (ret) {
		printk(KERN_ERR "%s: couldn't get irq %d\n", dev->name, dev->irq);
		elmc_id_reset586();
		return ret;
	}
	alloc586(dev);
	init586(dev);
	startrecv586(dev);
	netif_start_queue(dev);
	return 0;		/* most done by init */
}

static int elmc_open(struct net_device *dev)
{
	int ret;

	elmc_id_attn586();	/* disable interrupts */

	ret = request_irq(dev->irq, elmc_interrupt, IRQF_SHARED,
			  dev->name, dev);
	if (ret) {
		pr_err("%s: couldn't get irq %d\n", dev->name, dev->irq);
		elmc_id_reset586();
		return ret;
	}
	alloc586(dev);
	init586(dev);
	startrecv586(dev);
	netif_start_queue(dev);
	return 0;		/* most done by init */
}

static int __init check586(struct net_device *dev, unsigned long where, unsigned size)
{
	struct priv *p = (struct priv *) dev->priv;
	char *iscp_addrs[2];
	int i = 0;

	p->base = (unsigned long) bus_to_virt((unsigned long)where) + size - 0x01000000;
	p->memtop = bus_to_virt((unsigned long)where) + size;
	p->scp = (struct scp_struct *)(p->base + SCP_DEFAULT_ADDRESS);
	memset((char *) p->scp, 0, sizeof(struct scp_struct));
	p->scp->sysbus = SYSBUSVAL;	/* 1 = 8Bit-Bus, 0 = 16 Bit */

	iscp_addrs[0] = bus_to_virt((unsigned long)where);
	iscp_addrs[1] = (char *) p->scp - sizeof(struct iscp_struct);

	for (i = 0; i < 2; i++) {
		p->iscp = (struct iscp_struct *) iscp_addrs[i];
		memset((char *) p->iscp, 0, sizeof(struct iscp_struct));

		p->scp->iscp = make24(p->iscp);
		p->iscp->busy = 1;

		elmc_id_reset586();

		/* reset586 does an implicit CA */

		/* apparently, you sometimes have to kick the 82586 twice... */
		elmc_id_attn586();
		DELAY(1);

		if (p->iscp->busy) {	/* i82586 clears 'busy' after successful init */
			return 0;
		}
	}
	return 1;
}

//.........这里部分代码省略.........
		break;
	case 9:
		mca_write_pos(slot, 3, 0x08);
		break;
	case 12:
		mca_write_pos(slot, 3, 0x01);
		break;
	}

	pr = dev->priv = kmalloc(sizeof(struct priv), GFP_KERNEL);
	if (dev->priv == NULL) {
		retval = -ENOMEM;
		goto err_out;
	}
	memset(pr, 0, sizeof(struct priv));

	pr->slot = slot;

	printk(KERN_INFO "%s: 3Com 3c523 Rev 0x%x at %#lx\n", dev->name, (int) revision,
	       dev->base_addr);

	/* Determine if we're using the on-board transceiver (i.e. coax) or
	   an external one.  The information is pretty much useless, but I
	   guess it's worth brownie points. */
	dev->if_port = (status & ELMC_STATUS_DISABLE_THIN);

	/* The 3c523 has a 24K chunk of memory.  The first 16K is the
	   shared memory, while the last 8K is for the EtherStart BIOS ROM.
	   Which we don't care much about here.  We'll just tell Linux that
	   we're using 16K.  MCA won't permit address space conflicts caused
	   by not mapping the other 8K. */
	dev->mem_start = shm_table[(status & ELMC_STATUS_MEMORY_SELECT) >> 3];

	/* We're using MCA, so it's a given that the information about memory
	   size is correct.  The Crynwr drivers do something like this. */

	elmc_id_reset586();	/* seems like a good idea before checking it... */

	size = 0x4000;		/* check for 16K mem */
	if (!check586(dev, dev->mem_start, size)) {
		printk(KERN_ERR "%s: memprobe, Can't find memory at 0x%lx!\n", dev->name,
		       dev->mem_start);
		kfree(dev->priv);
		dev->priv = NULL;
		retval = -ENODEV;
		goto err_out;
	}
	dev->mem_end = dev->mem_start + size;	/* set mem_end showed by 'ifconfig' */

	pr->memtop = bus_to_virt(dev->mem_start) + size;
	pr->base = (unsigned long) bus_to_virt(dev->mem_start) + size - 0x01000000;
	alloc586(dev);

	elmc_id_reset586();	/* make sure it doesn't generate spurious ints */

	/* set number of receive-buffs according to memsize */
	pr->num_recv_buffs = NUM_RECV_BUFFS_16;

	/* dump all the assorted information */
	printk(KERN_INFO "%s: IRQ %d, %sternal xcvr, memory %#lx-%#lx.\n", dev->name,
	       dev->irq, dev->if_port ? "ex" : "in", 
	       dev->mem_start, dev->mem_end - 1);

	/* The hardware address for the 3c523 is stored in the first six
	   bytes of the IO address. */
	printk(KERN_INFO "%s: hardware address ", dev->name);
	for (i = 0; i < 6; i++) {
		dev->dev_addr[i] = inb(dev->base_addr + i);
		printk(" %02x", dev->dev_addr[i]);
	}
	printk("\n");

	dev->open = &elmc_open;
	dev->stop = &elmc_close;
	dev->get_stats = &elmc_get_stats;
	dev->hard_start_xmit = &elmc_send_packet;
	dev->tx_timeout = &elmc_timeout;
	dev->watchdog_timeo = HZ;
#ifdef ELMC_MULTICAST
	dev->set_multicast_list = &set_multicast_list;
#else
	dev->set_multicast_list = NULL;
#endif
	dev->ethtool_ops = &netdev_ethtool_ops;
	
	ether_setup(dev);

	/* note that we haven't actually requested the IRQ from the kernel.
	   That gets done in elmc_open().  I'm not sure that's such a good idea,
	   but it works, so I'll go with it. */

#ifndef ELMC_MULTICAST
        dev->flags&=~IFF_MULTICAST;     /* Multicast doesn't work */
#endif

	return 0;
err_out:
	release_region(dev->base_addr, ELMC_IO_EXTENT);
	return retval;
}