de620.c

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		dev->name,
		"network cable problem"
		);
	/* Restart the adapter. */
	if (!adapter_init(dev)) /* maybe close it */
		netif_wake_queue(dev);
}

/*******************************************************
 *
 * Copy a buffer to the adapter transmit page memory.
 * Start sending.
 */
static int de620_start_xmit(struct sk_buff *skb, struct net_device *dev)
{
	unsigned long flags;
	int len;
	byte *buffer = skb->data;
	byte using_txbuf;

	using_txbuf = de620_tx_buffs(dev); /* Peek at the adapter */
	
	netif_stop_queue(dev);
	

	if ((len = skb->len) < RUNT)
		len = RUNT;
	if (len & 1) /* send an even number of bytes */
		++len;

	/* Start real output */
	save_flags(flags);
	cli();

	PRINTK(("de620_start_xmit: len=%d, bufs 0x%02x\n",
		(int)skb->len, using_txbuf));

	/* select a free tx buffer. if there is one... */
	switch (using_txbuf) {
	default: /* both are free: use TXBF0 */
	case TXBF1: /* use TXBF0 */
		de620_send_command(dev,W_CR | RW0);
		using_txbuf |= TXBF0;
		break;

	case TXBF0: /* use TXBF1 */
		de620_send_command(dev,W_CR | RW1);
		using_txbuf |= TXBF1;
		break;

	case (TXBF0 | TXBF1): /* NONE!!! */
		printk(KERN_WARNING "%s: No tx-buffer available!\n", dev->name);
		restore_flags(flags);
		return 1;
		break;
	}
	de620_write_block(dev, buffer, len);

	dev->trans_start = jiffies;
	if(!(using_txbuf == (TXBF0 | TXBF1)))
		netif_wake_queue(dev);

	((struct net_device_stats *)(dev->priv))->tx_packets++;
	restore_flags(flags); /* interrupts maybe back on */
	dev_kfree_skb (skb);
	return 0;
}

/*****************************************************
 *
 * Handle the network interface interrupts.
 *
 */
static void de620_interrupt(int irq_in, void *dev_id, struct pt_regs *regs)
{
	struct net_device *dev = dev_id;
	byte irq_status;
	int bogus_count = 0;
	int again = 0;

	/* This might be deleted now, no crummy drivers present :-) Or..? */
	if ((dev == NULL) || (irq != irq_in)) {
		printk("%s: bogus interrupt %d\n", dev?dev->name:"de620", irq_in);
		return;
	}

	/* Read the status register (_not_ the status port) */
	irq_status = de620_get_register(dev, R_STS);

	PRINTK(("de620_interrupt (%2.2X)\n", irq_status));

	if (irq_status & RXGOOD) {
		do {
			again = de620_rx_intr(dev);
			PRINTK(("again=%d\n", again));
		}
		while (again && (++bogus_count < 100));
	}

	if(de620_tx_buffs(dev) != (TXBF0 | TXBF1))
		netif_wake_queue(dev);
}

/**************************************
 *
 * Get a packet from the adapter
 *
 * Send it "upstairs"
 *
 */
static int de620_rx_intr(struct net_device *dev)
{
	struct header_buf {
		byte		status;
		byte		Rx_NextPage;
		unsigned short	Rx_ByteCount;
	} header_buf;
	struct sk_buff *skb;
	int size;
	byte *buffer;
	byte pagelink;
	byte curr_page;

	PRINTK(("de620_rx_intr: next_rx_page = %d\n", next_rx_page));

	/* Tell the adapter that we are going to read data, and from where */
	de620_send_command(dev, W_CR | RRN);
	de620_set_register(dev, W_RSA1, next_rx_page);
	de620_set_register(dev, W_RSA0, 0);

	/* Deep breath, and away we goooooo */
	de620_read_block(dev, (byte *)&header_buf, sizeof(struct header_buf));
	PRINTK(("page status=0x%02x, nextpage=%d, packetsize=%d\n",
	header_buf.status, header_buf.Rx_NextPage, header_buf.Rx_ByteCount));

	/* Plausible page header? */
	pagelink = header_buf.Rx_NextPage;
	if ((pagelink < first_rx_page) || (last_rx_page < pagelink)) {
		/* Ouch... Forget it! Skip all and start afresh... */
		printk(KERN_WARNING "%s: Ring overrun? Restoring...\n", dev->name);
		/* You win some, you lose some. And sometimes plenty... */
		adapter_init(dev);
		netif_wake_queue(dev);
		((struct net_device_stats *)(dev->priv))->rx_over_errors++;
		return 0;
	}

	/* OK, this look good, so far. Let's see if it's consistent... */
	/* Let's compute the start of the next packet, based on where we are */
	pagelink = next_rx_page +
		((header_buf.Rx_ByteCount + (4 - 1 + 0x100)) >> 8);

	/* Are we going to wrap around the page counter? */
	if (pagelink > last_rx_page)
		pagelink -= (last_rx_page - first_rx_page + 1);

	/* Is the _computed_ next page number equal to what the adapter says? */
	if (pagelink != header_buf.Rx_NextPage) {
		/* Naah, we'll skip this packet. Probably bogus data as well */
		printk(KERN_WARNING "%s: Page link out of sync! Restoring...\n", dev->name);
		next_rx_page = header_buf.Rx_NextPage; /* at least a try... */
		de620_send_command(dev, W_DUMMY);
		de620_set_register(dev, W_NPRF, next_rx_page);
		((struct net_device_stats *)(dev->priv))->rx_over_errors++;
		return 0;
	}
	next_rx_page = pagelink;

	size = header_buf.Rx_ByteCount - 4;
	if ((size < RUNT) || (GIANT < size)) {
		printk(KERN_WARNING "%s: Illegal packet size: %d!\n", dev->name, size);
	}
	else { /* Good packet? */
		skb = dev_alloc_skb(size+2);
		if (skb == NULL) { /* Yeah, but no place to put it... */
			printk(KERN_WARNING "%s: Couldn't allocate a sk_buff of size %d.\n",
				dev->name, size);
			((struct net_device_stats *)(dev->priv))->rx_dropped++;
		}
		else { /* Yep! Go get it! */
			skb_reserve(skb,2);	/* Align */
			skb->dev = dev;
			skb->used = 0;
			/* skb->data points to the start of sk_buff data area */
			buffer = skb_put(skb,size);
			/* copy the packet into the buffer */
			de620_read_block(dev, buffer, size);
			PRINTK(("Read %d bytes\n", size));
			skb->protocol=eth_type_trans(skb,dev);
			netif_rx(skb); /* deliver it "upstairs" */
			/* count all receives */
			((struct net_device_stats *)(dev->priv))->rx_packets++;
		}
	}

	/* Let's peek ahead to see if we have read the last current packet */
	/* NOTE! We're _not_ checking the 'EMPTY'-flag! This seems better... */
	curr_page = de620_get_register(dev, R_CPR);
	de620_set_register(dev, W_NPRF, next_rx_page);
	PRINTK(("next_rx_page=%d CPR=%d\n", next_rx_page, curr_page));

	return (next_rx_page != curr_page); /* That was slightly tricky... */
}

/*********************************************
 *
 * Reset the adapter to a known state
 *
 */
static int adapter_init(struct net_device *dev)
{
	int i;
	static int was_down = 0;

	if ((nic_data.Model == 3) || (nic_data.Model == 0)) { /* CT */
		EIPRegister = NCTL0;
		if (nic_data.Media != 1)
			EIPRegister |= NIS0;	/* not BNC */
	}
	else if (nic_data.Model == 2) { /* UTP */
		EIPRegister = NCTL0 | NIS0;
	}

	if (utp)
		EIPRegister = NCTL0 | NIS0;
	if (bnc)
		EIPRegister = NCTL0;

	de620_send_command(dev, W_CR | RNOP | CLEAR);
	de620_send_command(dev, W_CR | RNOP);

	de620_set_register(dev, W_SCR, SCR_DEF);
	/* disable recv to wait init */
	de620_set_register(dev, W_TCR, RXOFF);

	/* Set the node ID in the adapter */
	for (i = 0; i < 6; ++i) { /* W_PARn = 0xaa + n */
		de620_set_register(dev, W_PAR0 + i, dev->dev_addr[i]);
	}

	de620_set_register(dev, W_EIP, EIPRegister);

	next_rx_page = first_rx_page = DE620_RX_START_PAGE;
	if (nic_data.RAM_Size)
		last_rx_page = nic_data.RAM_Size - 1;
	else /* 64k RAM */
		last_rx_page = 255;

	de620_set_register(dev, W_SPR, first_rx_page); /* Start Page Register*/
	de620_set_register(dev, W_EPR, last_rx_page);  /* End Page Register */
	de620_set_register(dev, W_CPR, first_rx_page);/*Current Page Register*/
	de620_send_command(dev, W_NPR | first_rx_page); /* Next Page Register*/
	de620_send_command(dev, W_DUMMY);
	de620_set_delay(dev);

	/* Final sanity check: Anybody out there? */
	/* Let's hope some bits from the statusregister make a good check */
#define CHECK_MASK (  0 | TXSUC |  T16  |  0  | RXCRC | RXSHORT |  0  |  0  )
#define CHECK_OK   (  0 |   0   |  0    |  0  |   0   |   0     |  0  |  0  )
        /* success:   X     0      0       X      0       0        X     X  */
        /* ignore:   EEDI                RXGOOD                   COLS  LNKS*/

	if (((i = de620_get_register(dev, R_STS)) & CHECK_MASK) != CHECK_OK) {
		printk(KERN_ERR "%s: Something has happened to the DE-620!  Please check it"
#ifdef SHUTDOWN_WHEN_LOST
			" and do a new ifconfig"
#endif
			"! (%02x)\n", dev->name, i);
#ifdef SHUTDOWN_WHEN_LOST
		/* Goodbye, cruel world... */
		dev->flags &= ~IFF_UP;
		de620_close(dev);
#endif
		was_down = 1;
		return 1; /* failed */
	}
	if (was_down) {
		printk(KERN_WARNING "%s: Thanks, I feel much better now!\n", dev->name);
		was_down = 0;
	}

	/* All OK, go ahead... */
	de620_set_register(dev, W_TCR, TCR_DEF);

	return 0; /* all ok */
}

/******************************************************************************
 *
 * Only start-up code below
 *
 */
/****************************************
 *
 * Check if there is a DE-620 connected
 */
int __init de620_probe(struct net_device *dev)
{
	static struct net_device_stats de620_netstats;
	int i;
	byte checkbyte = 0xa5;

	SET_MODULE_OWNER(dev);

	/*
	 * This is where the base_addr and irq gets set.
	 * Tunable at compile-time and insmod-time
	 */
	dev->base_addr = io;
	dev->irq       = irq;

	if (de620_debug)
		printk(version);

	printk(KERN_INFO "D-Link DE-620 pocket adapter");

	/* Initially, configure basic nibble mode, so we can read the EEPROM */
	NIC_Cmd = DEF_NIC_CMD;
	de620_set_register(dev, W_EIP, EIPRegister);

	/* Anybody out there? */
	de620_set_register(dev, W_CPR, checkbyte);
	checkbyte = de620_get_register(dev, R_CPR);

	if ((checkbyte != 0xa5) || (read_eeprom(dev) != 0)) {
		printk(" not identified in the printer port\n");
		return -ENODEV;
	}

#if 0 /* Not yet */
	if (check_region(dev->base_addr, 3)) {
		printk(", port 0x%x busy\n", dev->base_addr);
		return -EBUSY;
	}
#endif
	request_region(dev->base_addr, 3, "de620");

	/* else, got it! */
	printk(", Ethernet Address: %2.2X",
		dev->dev_addr[0] = nic_data.NodeID[0]);
	for (i = 1; i < ETH_ALEN; i++) {
		printk(":%2.2X", dev->dev_addr[i] = nic_data.NodeID[i]);
		dev->broadcast[i] = 0xff;
	}

	printk(" (%dk RAM,",
		(nic_data.RAM_Size) ? (nic_data.RAM_Size >> 2) : 64);

	if (nic_data.Media == 1)
		printk(" BNC)\n");
	else
		printk(" UTP)\n");

	/* Initialize the device structure. */
	dev->priv = &de620_netstats;

	memset(dev->priv, 0, sizeof(struct net_device_stats));
	dev->get_stats 		= get_stats;
	dev->open 		= de620_open;
	dev->stop 		= de620_close;
	dev->hard_start_xmit 	= de620_start_xmit;
	dev->tx_timeout 	= de620_timeout;
	dev->watchdog_timeo	= HZ*2;
	dev->set_multicast_list = de620_set_multicast_list;
	
	/* base_addr and irq are already set, see above! */

	ether_setup(dev);

	/* dump eeprom */
	if (de620_debug) {
		printk("\nEEPROM contents:\n");
		printk("RAM_Size = 0x%02X\n", nic_data.RAM_Size);
		printk("NodeID = %02X:%02X:%02X:%02X:%02X:%02X\n",
			nic_data.NodeID[0], nic_data.NodeID[1],
			nic_data.NodeID[2], nic_data.NodeID[3],
			nic_data.NodeID[4], nic_data.NodeID[5]);
		printk("Model = %d\n", nic_data.Model);
		printk("Media = %d\n", nic_data.Media);
		printk("SCR = 0x%02x\n", nic_data.SCR);
	}

	return 0;
}

/**********************************
 *
 * Read info from on-board EEPROM
 *
 * Note: Bitwise serial I/O to/from the EEPROM vi the status _register_!
 */
#define sendit(dev,data) de620_set_register(dev, W_EIP, data | EIPRegister);

static unsigned short __init ReadAWord(struct net_device *dev, int from)
{
	unsigned short data;
	int nbits;

	/* cs   [__~~] SET SEND STATE */
	/* di   [____]                */
	/* sck  [_~~_]                */
	sendit(dev, 0); sendit(dev, 1); sendit(dev, 5); sendit(dev, 4);

	/* Send the 9-bit address from where we want to read the 16-bit word */
	for (nbits = 9; nbits > 0; --nbits, from <<= 1) {
		if (from & 0x0100) { /* bit set? */
			/* cs    [~~~~] SEND 1 */
			/* di    [~~~~]        */
			/* sck   [_~~_]        */
			sendit(dev, 6); sendit(dev, 7); sendit(dev, 7); sendit(dev, 6);
		}
		else {
			/* cs    [~~~~] SEND 0 */
			/* di    [____]        */
			/* sck   [_~~_]        */
			sendit(dev, 4); sendit(dev, 5); sendit(dev, 5); sendit(dev, 4);
		}
	}

	/* Shift in the 16-bit word. The bits appear serially in EEDI (=0x80) */
	for (data = 0, nbits = 16; nbits > 0; --nbits) {
		/* cs    [~~~~] SEND 0 */
		/* di    [____]        */
		/* sck   [_~~_]        */
		sendit(dev, 4); sendit(dev, 5); sendit(dev, 5); sendit(dev, 4);
		data = (data << 1) | ((de620_get_register(dev, R_STS) & EEDI) >> 7);
	}
	/* cs    [____] RESET SEND STATE */
	/* di    [____]                  */
	/* sck   [_~~_]                  */
	sendit(dev, 0); sendit(dev, 1); sendit(dev, 1); sendit(dev, 0);

	return data;
}

static int __init read_eeprom(struct net_device *dev)
{
	unsigned short wrd;

	/* D-Link Ethernet addresses are in the series  00:80:c8:7X:XX:XX:XX */
	wrd = ReadAWord(dev, 0x1aa);	/* bytes 0 + 1 of NodeID */
	if (!clone && (wrd != htons(0x0080))) /* Valid D-Link ether sequence? */
		return -1; /* Nope, not a DE-620 */
	nic_data.NodeID[0] = wrd & 0xff;
	nic_data.NodeID[1] = wrd >> 8;

	wrd = ReadAWord(dev, 0x1ab);	/* bytes 2 + 3 of NodeID */
	if (!clone && ((wrd & 0xff) != 0xc8)) /* Valid D-Link ether sequence? */
		return -1; /* Nope, not a DE-620 */
	nic_data.NodeID[2] = wrd & 0xff;
	nic_data.NodeID[3] = wrd >> 8;

	wrd = ReadAWord(dev, 0x1ac);	/* bytes 4 + 5 of NodeID */
	nic_data.NodeID[4] = wrd & 0xff;
	nic_data.NodeID[5] = wrd >> 8;

	wrd = ReadAWord(dev, 0x1ad);	/* RAM size in pages (256 bytes). 0 = 64k */
	nic_data.RAM_Size = (wrd >> 8);

	wrd = ReadAWord(dev, 0x1ae);	/* hardware model (CT = 3) */
	nic_data.Model = (wrd & 0xff);

	wrd = ReadAWord(dev, 0x1af); /* media (indicates BNC/UTP) */
	nic_data.Media = (wrd & 0xff);

	wrd = ReadAWord(dev, 0x1a8); /* System Configuration Register */
	nic_data.SCR = (wrd >> 8);

	return 0; /* no errors */
}

/******************************************************************************
 *
 * Loadable module skeleton
 *
 */
#ifdef MODULE
static struct net_device de620_dev;

int init_module(void)
{
	de620_dev.init = de620_probe;
	if (register_netdev(&de620_dev) != 0)
		return -EIO;
	return 0;
}

void cleanup_module(void)
{
	unregister_netdev(&de620_dev);
	release_region(de620_dev.base_addr, 3);
}
#endif /* MODULE */

/*
 * (add '-DMODULE' when compiling as loadable module)
 *
 * compile-command:
 *	gcc -D__KERNEL__ -Wall -Wstrict-prototypes -O2 \
 *	 -fomit-frame-pointer -m486 \
 *	-I/usr/src/linux/include -I../../net/inet -c de620.c
*/
/*
 * Local variables:
 *  kernel-compile-command: "gcc -D__KERNEL__ -Ilinux/include -I../../net/inet -Wall -Wstrict-prototypes -O2 -m486 -c de620.c"
 *  module-compile-command: "gcc -D__KERNEL__ -DMODULE -Ilinux/include -I../../net/inet -Wall -Wstrict-prototypes -O2 -m486 -c de620.c"
 *  compile-command: "gcc -D__KERNEL__ -DMODULE -Ilinux/include -I../../net/inet -Wall -Wstrict-prototypes -O2 -m486 -c de620.c"
 * End:
 */