#include <linux/kernel.h>
#include <linux/string.h>
#include <linux/errno.h>
#include <linux/ioport.h>
#include <linux/slab.h>
#include <linux/interrupt.h>
#include <linux/delay.h>
#include <linux/time.h>
#include <linux/mca-legacy.h>
#include <linux/module.h>
#include <linux/netdevice.h>
#include <linux/etherdevice.h>
#include <linux/skbuff.h>
#include <linux/bitops.h>

#include <asm/processor.h>
#include <asm/io.h>

#define _IBM_LANA_DRIVER_
#include "ibmlana.h"

#undef DEBUG

#define DRV_NAME "ibmlana"

/* ------------------------------------------------------------------------
 * global static data - not more since we can handle multiple boards and
 * have to pack all state info into the device struct!
 * ------------------------------------------------------------------------ */

static char *MediaNames[Media_Count] = {
	"10BaseT", "10Base5", "Unknown", "10Base2"
};

/* ------------------------------------------------------------------------
 * private subfunctions
 * ------------------------------------------------------------------------ */

#ifdef DEBUG
  /* dump all registers */

static void dumpregs(struct net_device *dev)
{
	int z;

	for (z = 0; z < 160; z += 2) {
		if (!(z & 15))
			printk("REGS: %04x:", z);
		printk(" %04x", inw(dev->base_addr + z));
		if ((z & 15) == 14)
			printk("\n");
	}
}

/* dump parts of shared memory - only needed during debugging */

static void dumpmem(struct net_device *dev, u32 start, u32 len)
{
	ibmlana_priv *priv = netdev_priv(dev);
	int z;

	printk("Address %04x:\n", start);
	for (z = 0; z < len; z++) {
		if ((z & 15) == 0)
			printk("%04x:", z);
		printk(" %02x", readb(priv->base + start + z));
		if ((z & 15) == 15)
			printk("\n");
	}
	if ((z & 15) != 0)
		printk("\n");
}

/* print exact time - ditto */

static void PrTime(void)
{
	struct timeval tv;

	do_gettimeofday(&tv);
	printk("%9d:%06d: ", (int) tv.tv_sec, (int) tv.tv_usec);
}
#endif				/* DEBUG */

/* deduce resources out of POS registers */

static void getaddrs(int slot, int *base, int *memlen, int *iobase,
		     int *irq, ibmlana_medium * medium)
{
	u_char pos0, pos1;

	pos0 = mca_read_stored_pos(slot, 2);
	pos1 = mca_read_stored_pos(slot, 3);

	*base = 0xc0000 + ((pos1 & 0xf0) << 9);
	*memlen = (pos1 & 0x01) ? 0x8000 : 0x4000;
	*iobase = (pos0 & 0xe0) << 7;
	switch (pos0 & 0x06) {
	case 0:
		*irq = 5;
		break;
	case 2:
		*irq = 15;
		break;
	case 4:
		*irq = 10;
		break;
	case 6:
		*irq = 11;
		break;
	}
	*medium = (pos0 & 0x18) >> 3;
}

/* wait on register value with mask and timeout */

static int wait_timeout(struct net_device *dev, int regoffs, u16 mask,
			u16 value, int timeout)
{
	unsigned long fin = jiffies + timeout;

	while (time_before(jiffies,fin))
		if ((inw(dev->base_addr + regoffs) & mask) == value)
			return 1;

	return 0;
}


/* reset the whole board */

static void ResetBoard(struct net_device *dev)
{
	unsigned char bcmval;

	/* read original board control value */

	bcmval = inb(dev->base_addr + BCMREG);

	/* set reset bit for a while */

	bcmval |= BCMREG_RESET;
	outb(bcmval, dev->base_addr + BCMREG);
	udelay(10);
	bcmval &= ~BCMREG_RESET;
	outb(bcmval, dev->base_addr + BCMREG);

	/* switch over to RAM again */

	bcmval |= BCMREG_RAMEN | BCMREG_RAMWIN;
	outb(bcmval, dev->base_addr + BCMREG);
}

/* calculate RAM layout & set up descriptors in RAM */

static void InitDscrs(struct net_device *dev)
{
	ibmlana_priv *priv = netdev_priv(dev);
	u32 addr, baddr, raddr;
	int z;
	tda_t tda;
	rda_t rda;
	rra_t rra;

	/* initialize RAM */

	memset_io(priv->base, 0xaa,
		      dev->mem_start - dev->mem_start);

	/* setup n TX descriptors - independent of RAM size */

	priv->tdastart = addr = 0;
	priv->txbufstart = baddr = sizeof(tda_t) * TXBUFCNT;
	for (z = 0; z < TXBUFCNT; z++) {
		tda.status = 0;
		tda.config = 0;
		tda.length = 0;
		tda.fragcount = 1;
		tda.startlo = baddr;
		tda.starthi = 0;
		tda.fraglength = 0;
		if (z == TXBUFCNT - 1)
			tda.link = priv->tdastart;
		else
			tda.link = addr + sizeof(tda_t);
		tda.link |= 1;
		memcpy_toio(priv->base + addr, &tda, sizeof(tda_t));
		addr += sizeof(tda_t);
		baddr += PKTSIZE;
	}

	/* calculate how many receive buffers fit into remaining memory */

	priv->rxbufcnt = (dev->mem_end - dev->mem_start - baddr) / (sizeof(rra_t) + sizeof(rda_t) + PKTSIZE);

	/* calculate receive addresses */

	priv->rrastart = raddr = priv->txbufstart + (TXBUFCNT * PKTSIZE);
	priv->rdastart = addr = priv->rrastart + (priv->rxbufcnt * sizeof(rra_t));
	priv->rxbufstart = baddr = priv->rdastart + (priv->rxbufcnt * sizeof(rda_t));

	for (z = 0; z < priv->rxbufcnt; z++) {
		rra.startlo = baddr;
		rra.starthi = 0;
		rra.cntlo = PKTSIZE >> 1;
		rra.cnthi = 0;
		memcpy_toio(priv->base + raddr, &rra, sizeof(rra_t));

		rda.status = 0;
		rda.length = 0;
		rda.startlo = 0;
		rda.starthi = 0;
		rda.seqno = 0;
		if (z < priv->rxbufcnt - 1)
			rda.link = addr + sizeof(rda_t);
		else
			rda.link = 1;
		rda.inuse = 1;
		memcpy_toio(priv->base + addr, &rda, sizeof(rda_t));

		baddr += PKTSIZE;
		raddr += sizeof(rra_t);
		addr += sizeof(rda_t);
	}

	/* initialize current pointers */

	priv->nextrxdescr = 0;
	priv->lastrxdescr = priv->rxbufcnt - 1;
	priv->nexttxdescr = 0;
	priv->currtxdescr = 0;
	priv->txusedcnt = 0;
	memset(priv->txused, 0, sizeof(priv->txused));
}

/* set up Rx + Tx descriptors in SONIC */

static int InitSONIC(struct net_device *dev)
{
	ibmlana_priv *priv = netdev_priv(dev);

	/* set up start & end of resource area */

	outw(0, SONIC_URRA);
	outw(priv->rrastart, dev->base_addr + SONIC_RSA);
	outw(priv->rrastart + (priv->rxbufcnt * sizeof(rra_t)), dev->base_addr + SONIC_REA);
	outw(priv->rrastart, dev->base_addr + SONIC_RRP);
	outw(priv->rrastart, dev->base_addr + SONIC_RWP);

	/* set EOBC so that only one packet goes into one buffer */

	outw((PKTSIZE - 4) >> 1, dev->base_addr + SONIC_EOBC);

	/* let SONIC read the first RRA descriptor */

	outw(CMDREG_RRRA, dev->base_addr + SONIC_CMDREG);
	if (!wait_timeout(dev, SONIC_CMDREG, CMDREG_RRRA, 0, 2)) {
		printk(KERN_ERR "%s: SONIC did not respond on RRRA command - giving up.", dev->name);
		return 0;
	}

	/* point SONIC to the first RDA */

	outw(0, dev->base_addr + SONIC_URDA);
	outw(priv->rdastart, dev->base_addr + SONIC_CRDA);

	/* set upper half of TDA address */

	outw(0, dev->base_addr + SONIC_UTDA);

	return 1;
}

/* stop SONIC so we can reinitialize it */

static void StopSONIC(struct net_device *dev)
{
	/* disable interrupts */

	outb(inb(dev->base_addr + BCMREG) & (~BCMREG_IEN), dev->base_addr + BCMREG);
	outb(0, dev->base_addr + SONIC_IMREG);

	/* reset the SONIC */

	outw(CMDREG_RST, dev->base_addr + SONIC_CMDREG);
	udelay(10);
	outw(CMDREG_RST, dev->base_addr + SONIC_CMDREG);
}

/* initialize card and SONIC for proper operation */

static void putcam(camentry_t * cams, int *camcnt, char *addr)
{
	camentry_t *pcam = cams + (*camcnt);
	u8 *uaddr = (u8 *) addr;

	pcam->index = *camcnt;
	pcam->addr0 = (((u16) uaddr[1]) << 8) | uaddr[0];
	pcam->addr1 = (((u16) uaddr[3]) << 8) | uaddr[2];
	pcam->addr2 = (((u16) uaddr[5]) << 8) | uaddr[4];
	(*camcnt)++;
}

static void InitBoard(struct net_device *dev)
{
	ibmlana_priv *priv = netdev_priv(dev);
	int camcnt;
	camentry_t cams[16];
	u32 cammask;
	struct dev_mc_list *mcptr;
	u16 rcrval;

	/* reset the SONIC */

	outw(CMDREG_RST, dev->base_addr + SONIC_CMDREG);
	udelay(10);

	/* clear all spurious interrupts */

	outw(inw(dev->base_addr + SONIC_ISREG), dev->base_addr + SONIC_ISREG);

	/* set up the SONIC's bus interface - constant for this adapter -
	   must be done while the SONIC is in reset */

	outw(DCREG_USR1 | DCREG_USR0 | DCREG_WC1 | DCREG_DW32, dev->base_addr + SONIC_DCREG);
	outw(0, dev->base_addr + SONIC_DCREG2);

	/* remove reset form the SONIC */

	outw(0, dev->base_addr + SONIC_CMDREG);
	udelay(10);

	/* data sheet requires URRA to be programmed before setting up the CAM contents */

	outw(0, dev->base_addr + SONIC_URRA);

	/* program the CAM entry 0 to the device address */

	camcnt = 0;
	putcam(cams, &camcnt, dev->dev_addr);

	/* start putting the multicast addresses into the CAM list.  Stop if
	   it is full. */

	for (mcptr = dev->mc_list; mcptr != NULL; mcptr = mcptr->next) {
		putcam(cams, &camcnt, mcptr->dmi_addr);
		if (camcnt == 16)
			break;
	}

	/* calculate CAM mask */

	cammask = (1 << camcnt) - 1;

	/* feed CDA into SONIC, initialize RCR value (always get broadcasts) */

	memcpy_toio(priv->base, cams, sizeof(camentry_t) * camcnt);
	memcpy_toio(priv->base + (sizeof(camentry_t) * camcnt), &cammask, sizeof(cammask));

#ifdef DEBUG
	printk("CAM setup:\n");
	dumpmem(dev, 0, sizeof(camentry_t) * camcnt + sizeof(cammask));
#endif

	outw(0, dev->base_addr + SONIC_CAMPTR);
	outw(camcnt, dev->base_addr + SONIC_CAMCNT);
	outw(CMDREG_LCAM, dev->base_addr + SONIC_CMDREG);
	if (!wait_timeout(dev, SONIC_CMDREG, CMDREG_LCAM, 0, 2)) {
		printk(KERN_ERR "%s:SONIC did not respond on LCAM command - giving up.", dev->name);
		return;
	} else {
		/* clear interrupt condition */

		outw(ISREG_LCD, dev->base_addr + SONIC_ISREG);

#ifdef DEBUG
		printk("Loading CAM done, address pointers %04x:%04x\n",
		       inw(dev->base_addr + SONIC_URRA),
		       inw(dev->base_addr + SONIC_CAMPTR));
		{
			int z;

			printk("\n-->CAM: PTR %04x CNT %04x\n",
			       inw(dev->base_addr + SONIC_CAMPTR),
			       inw(dev->base_addr + SONIC_CAMCNT));
			outw(CMDREG_RST, dev->base_addr + SONIC_CMDREG);
			for (z = 0; z < camcnt; z++) {
				outw(z, dev->base_addr + SONIC_CAMEPTR);
				printk("Entry %d: %04x %04x %04x\n", z,
				       inw(dev->base_addr + SONIC_CAMADDR0),
				       inw(dev->base_addr + SONIC_CAMADDR1),
				       inw(dev->base_addr + SONIC_CAMADDR2));
			}
			outw(0, dev->base_addr + SONIC_CMDREG);
		}
#endif
	}

	rcrval = RCREG_BRD | RCREG_LB_NONE;

	/* if still multicast addresses left or ALLMULTI is set, set the multicast
	   enable bit */

	if ((dev->flags & IFF_ALLMULTI) || (mcptr != NULL))
		rcrval |= RCREG_AMC;

	/* promiscous mode ? */

	if (dev->flags & IFF_PROMISC)
		rcrval |= RCREG_PRO;

	/* program receive mode */

	outw(rcrval, dev->base_addr + SONIC_RCREG);
#ifdef DEBUG
	printk("\nRCRVAL: %04x\n", rcrval);
#endif

	/* set up descriptors in shared memory + feed them into SONIC registers */

	InitDscrs(dev);
	if (!InitSONIC(dev))
		return;

	/* reset all pending interrupts */

	outw(0xffff, dev->base_addr + SONIC_ISREG);

	/* enable transmitter + receiver interrupts */

	outw(CMDREG_RXEN, dev->base_addr + SONIC_CMDREG);
	outw(IMREG_PRXEN | IMREG_RBEEN | IMREG_PTXEN | IMREG_TXEREN, dev->base_addr + SONIC_IMREG);

	/* turn on card interrupts */

	outb(inb(dev->base_addr + BCMREG) | BCMREG_IEN, dev->base_addr + BCMREG);

#ifdef DEBUG
	printk("Register dump after initialization:\n");
	dumpregs(dev);
#endif
}

/* start transmission of a descriptor */

static void StartTx(struct net_device *dev, int descr)
{
	ibmlana_priv *priv = netdev_priv(dev);
	int addr;

	addr = priv->tdastart + (descr * sizeof(tda_t));

	/* put descriptor address into SONIC */

	outw(addr, dev->base_addr + SONIC_CTDA);

	/* trigger transmitter */

	priv->currtxdescr = descr;
	outw(CMDREG_TXP, dev->base_addr + SONIC_CMDREG);
}

/* ------------------------------------------------------------------------
 * interrupt handler(s)
 * ------------------------------------------------------------------------ */

/* receive buffer area exhausted */

static void irqrbe_handler(struct net_device *dev)
{
	ibmlana_priv *priv = netdev_priv(dev);

	/* point the SONIC back to the RRA start */

	outw(priv->rrastart, dev->base_addr + SONIC_RRP);
	outw(priv->rrastart, dev->base_addr + SONIC_RWP);
}

/* receive interrupt */

static void irqrx_handler(struct net_device *dev)
{
	ibmlana_priv *priv = netdev_priv(dev);
	rda_t rda;
	u32 rdaaddr, lrdaaddr;

	/* loop until ... */

	while (1) {
		/* read descriptor that was next to be filled by SONIC */

		rdaaddr = priv->rdastart + (priv->nextrxdescr * sizeof(rda_t));
		lrdaaddr = priv->rdastart + (priv->lastrxdescr * sizeof(rda_t));
		memcpy_fromio(&rda, priv->base + rdaaddr, sizeof(rda_t));

		/* iron out upper word halves of fields we use - SONIC will duplicate
		   bits 0..15 to 16..31 */

		rda.status &= 0xffff;
		rda.length &= 0xffff;
		rda.startlo &= 0xffff;

		/* stop if the SONIC still owns it, i.e. there is no data for us */

		if (rda.inuse)
			break;

		/* good packet? */

		else if (rda.status & RCREG_PRX) {
			struct sk_buff *skb;

			/* fetch buffer */

			skb = dev_alloc_skb(rda.length + 2);
			if (skb == NULL)
				priv->stat.rx_dropped++;
			else {
				/* copy out data */

				memcpy_fromio(skb_put(skb, rda.length),
					       priv->base +
					       rda.startlo, rda.length);

				/* set up skb fields */

				skb->protocol = eth_type_trans(skb, dev);
				skb->ip_summed = CHECKSUM_NONE;

				/* bookkeeping */
				dev->last_rx = jiffies;
				priv->stat.rx_packets++;
				priv->stat.rx_bytes += rda.length;

				/* pass to the upper layers */
				netif_rx(skb);
			}
		}

		/* otherwise check error status bits and increase statistics */

		else {
			priv->stat.rx_errors++;
			if (rda.status & RCREG_FAER)
				priv->stat.rx_frame_errors++;
			if (rda.status & RCREG_CRCR)
				priv->stat.rx_crc_errors++;
		}

		/* descriptor processed, will become new last descriptor in queue */

		rda.link = 1;
		rda.inuse = 1;
		memcpy_toio(priv->base + rdaaddr, &rda,
			     sizeof(rda_t));

		/* set up link and EOL = 0 in currently last descriptor. Only write
		   the link field since the SONIC may currently already access the
		   other fields. */

		memcpy_toio(priv->base + lrdaaddr + 20, &rdaaddr, 4);

		/* advance indices */

		priv->lastrxdescr = priv->nextrxdescr;
		if ((++priv->nextrxdescr) >= priv->rxbufcnt)
			priv->nextrxdescr = 0;
	}
}

/* transmit interrupt */

static void irqtx_handler(struct net_device *dev)
{
	ibmlana_priv *priv = netdev_priv(dev);
	tda_t tda;

	/* fetch descriptor (we forgot the size ;-) */
	memcpy_fromio(&tda, priv->base + priv->tdastart + (priv->currtxdescr * sizeof(tda_t)), sizeof(tda_t));

	/* update statistics */
	priv->stat.tx_packets++;
	priv->stat.tx_bytes += tda.length;

	/* update our pointers */
	priv->txused[priv->currtxdescr] = 0;
	priv->txusedcnt--;

	/* if there are more descriptors present in RAM, start them */
	if (priv->txusedcnt > 0)
		StartTx(dev, (priv->currtxdescr + 1) % TXBUFCNT);

	/* tell the upper layer we can go on transmitting */
	netif_wake_queue(dev);
}

static void irqtxerr_handler(struct net_device *dev)
{
	ibmlana_priv *priv = netdev_priv(dev);
	tda_t tda;

	/* fetch descriptor to check status */
	memcpy_fromio(&tda, priv->base + priv->tdastart + (priv->currtxdescr * sizeof(tda_t)), sizeof(tda_t));

	/* update statistics */
	priv->stat.tx_errors++;
	if (tda.status & (TCREG_NCRS | TCREG_CRSL))
		priv->stat.tx_carrier_errors++;
	if (tda.status & TCREG_EXC)
		priv->stat.tx_aborted_errors++;
	if (tda.status & TCREG_OWC)
		priv->stat.tx_window_errors++;
	if (tda.status & TCREG_FU)
		priv->stat.tx_fifo_errors++;

	/* update our pointers */
	priv->txused[priv->currtxdescr] = 0;
	priv->txusedcnt--;

	/* if there are more descriptors present in RAM, start them */
	if (priv->txusedcnt > 0)
		StartTx(dev, (priv->currtxdescr + 1) % TXBUFCNT);

	/* tell the upper layer we can go on transmitting */
	netif_wake_queue(dev);
}

/* general interrupt entry */

static irqreturn_t irq_handler(int irq, void *device)
{
	struct net_device *dev = (struct net_device *) device;
	u16 ival;

	/* in case we're not meant... */
	if (!(inb(dev->base_addr + BCMREG) & BCMREG_IPEND))
		return IRQ_NONE;

	/* loop through the interrupt bits until everything is clear */
	while (1) {
		ival = inw(dev->base_addr + SONIC_ISREG);

		if (ival & ISREG_RBE) {
			irqrbe_handler(dev);
			outw(ISREG_RBE, dev->base_addr + SONIC_ISREG);
		}
		if (ival & ISREG_PKTRX) {
			irqrx_handler(dev);
			outw(ISREG_PKTRX, dev->base_addr + SONIC_ISREG);
		}
		if (ival & ISREG_TXDN) {
			irqtx_handler(dev);
			outw(ISREG_TXDN, dev->base_addr + SONIC_ISREG);
		}
		if (ival & ISREG_TXER) {
			irqtxerr_handler(dev);
			outw(ISREG_TXER, dev->base_addr + SONIC_ISREG);
		}
		break;
	}
	return IRQ_HANDLED;
}

/* ------------------------------------------------------------------------
 * driver methods
 * ------------------------------------------------------------------------ */

/* MCA info */

static int ibmlana_getinfo(char *buf, int slot, void *d)
{
	int len = 0, i;
	struct net_device *dev = (struct net_device *) d;
	ibmlana_priv *priv;

	/* can't say anything about an uninitialized device... */

	if (dev == NULL)
		return len;
	priv = netdev_priv(dev);

	/* print info */

	len += sprintf(buf + len, "IRQ: %d\n", priv->realirq);
	len += sprintf(buf + len, "I/O: %#lx\n", dev->base_addr);
	len += sprintf(buf + len, "Memory: %#lx-%#lx\n", dev->mem_start, dev->mem_end - 1);
	len += sprintf(buf + len, "Transceiver: %s\n", MediaNames[priv->medium]);
	len += sprintf(buf + len, "Device: %s\n", dev->name);
	len += sprintf(buf + len, "MAC address:");
	for (i = 0; i < 6; i++)
		len += sprintf(buf + len, " %02x", dev->dev_addr[i]);
	buf[len++] = '\n';
	buf[len] = 0;

	return len;
}

/* open driver.  Means also initialization and start of LANCE */

static int ibmlana_open(struct net_device *dev)
{
	int result;
	ibmlana_priv *priv = netdev_priv(dev);

	/* register resources - only necessary for IRQ */

	result = request_irq(priv->realirq, irq_handler, IRQF_SHARED | IRQF_SAMPLE_RANDOM, dev->name, dev);
	if (result != 0) {
		printk(KERN_ERR "%s: failed to register irq %d\n", dev->name, dev->irq);
		return result;
	}
	dev->irq = priv->realirq;

	/* set up the card and SONIC */
	InitBoard(dev);

	/* initialize operational flags */
	netif_start_queue(dev);
	return 0;
}

/* close driver.  Shut down board and free allocated resources */

static int ibmlana_close(struct net_device *dev)
{
	/* turn off board */

	/* release resources */
	if (dev->irq != 0)
		free_irq(dev->irq, dev);
	dev->irq = 0;
	return 0;
}

/* transmit a block. */

static int ibmlana_tx(struct sk_buff *skb, struct net_device *dev)
{
	ibmlana_priv *priv = netdev_priv(dev);
	int retval = 0, tmplen, addr;
	unsigned long flags;
	tda_t tda;
	int baddr;

	/* find out if there are free slots for a frame to transmit. If not,
	   the upper layer is in deep desperation and we simply ignore the frame. */

	if (priv->txusedcnt >= TXBUFCNT) {
		retval = -EIO;
		priv->stat.tx_dropped++;
		goto tx_done;
	}

	/* copy the frame data into the next free transmit buffer - fillup missing */
	tmplen = skb->len;
	if (tmplen < 60)
		tmplen = 60;
	baddr = priv->txbufstart + (priv->nexttxdescr * PKTSIZE);
	memcpy_toio(priv->base + baddr, skb->data, skb->len);

	/* copy filler into RAM - in case we're filling up...
	   we're filling a bit more than necessary, but that doesn't harm
	   since the buffer is far larger...
	   Sorry Linus for the filler string but I couldn't resist ;-) */

	if (tmplen > skb->len) {
		char *fill = "NetBSD is a nice OS too! ";
		unsigned int destoffs = skb->len, l = strlen(fill);

		while (destoffs < tmplen) {
			memcpy_toio(priv->base + baddr + destoffs, fill, l);
			destoffs += l;
		}
	}

	/* set up the new frame descriptor */
	addr = priv->tdastart + (priv->nexttxdescr * sizeof(tda_t));
	memcpy_fromio(&tda, priv->base + addr, sizeof(tda_t));
	tda.length = tda.fraglength = tmplen;
	memcpy_toio(priv->base + addr, &tda, sizeof(tda_t));

	/* if there were no active descriptors, trigger the SONIC */
	spin_lock_irqsave(&priv->lock, flags);

	priv->txusedcnt++;
	priv->txused[priv->nexttxdescr] = 1;

	/* are all transmission slots used up ? */
	if (priv->txusedcnt >= TXBUFCNT)
		netif_stop_queue(dev);

	if (priv->txusedcnt == 1)
		StartTx(dev, priv->nexttxdescr);
	priv->nexttxdescr = (priv->nexttxdescr + 1) % TXBUFCNT;

	spin_unlock_irqrestore(&priv->lock, flags);
tx_done:
	dev_kfree_skb(skb);
	return retval;
}

/* return pointer to Ethernet statistics */

static struct net_device_stats *ibmlana_stats(struct net_device *dev)
{
	ibmlana_priv *priv = netdev_priv(dev);
	return &priv->stat;
}

/* switch receiver mode. */

static void ibmlana_set_multicast_list(struct net_device *dev)
{
	/* first stop the SONIC... */
	StopSONIC(dev);
	/* ...then reinit it with the new flags */
	InitBoard(dev);
}

/* ------------------------------------------------------------------------
 * hardware check
 * ------------------------------------------------------------------------ */

static int startslot;		/* counts through slots when probing multiple devices */

static int ibmlana_probe(struct net_device *dev)
{
	int slot, z;
	int base = 0, irq = 0, iobase = 0, memlen = 0;
	ibmlana_priv *priv;
	ibmlana_medium medium;

	SET_MODULE_OWNER(dev);

	/* can't work without an MCA bus ;-) */
	if (MCA_bus == 0)
		return -ENODEV;

	base = dev->mem_start;
	irq = dev->irq;

	for (slot = startslot; (slot = mca_find_adapter(IBM_LANA_ID, slot)) != -1; slot++) {
		/* deduce card addresses */
		getaddrs(slot, &base, &memlen, &iobase, &irq, &medium);

		/* slot already in use ? */
		if (mca_is_adapter_used(slot))
			continue;
		/* were we looking for something different ? */
		if (dev->irq && dev->irq != irq)
			continue;
		if (dev->mem_start && dev->mem_start != base)
			continue;
		/* found something that matches */
		break;
	}

	/* nothing found ? */
	if (slot == -1)
		return (base != 0 || irq != 0) ? -ENXIO : -ENODEV;

	/* announce success */
	printk(KERN_INFO "%s: IBM LAN Adapter/A found in slot %d\n", dev->name, slot + 1);

	/* try to obtain I/O range */
	if (!request_region(iobase, IBM_LANA_IORANGE, DRV_NAME)) {
		printk(KERN_ERR "%s: cannot allocate I/O range at %#x!\n", DRV_NAME, iobase);
		startslot = slot + 1;
		return -EBUSY;
	}

	priv = netdev_priv(dev);
	priv->slot = slot;
	priv->realirq = irq;
	priv->medium = medium;
	spin_lock_init(&priv->lock);


	/* set base + irq for this device (irq not allocated so far) */

	dev->irq = 0;
	dev->mem_start = base;
	dev->mem_end = base + memlen;
	dev->base_addr = iobase;

	priv->base = ioremap(base, memlen);
	if (!priv->base) {
		printk(KERN_ERR "%s: cannot remap memory!\n", DRV_NAME);
		startslot = slot + 1;
		release_region(iobase, IBM_LANA_IORANGE);
		return -EBUSY;
	}

	/* make procfs entries */
	mca_set_adapter_name(slot, "IBM LAN Adapter/A");
	mca_set_adapter_procfn(slot, (MCA_ProcFn) ibmlana_getinfo, dev);

	mca_mark_as_used(slot);

	/* set methods */

	dev->open = ibmlana_open;
	dev->stop = ibmlana_close;
	dev->hard_start_xmit = ibmlana_tx;
	dev->do_ioctl = NULL;
	dev->get_stats = ibmlana_stats;
	dev->set_multicast_list = ibmlana_set_multicast_list;
	dev->flags |= IFF_MULTICAST;

	/* copy out MAC address */

	for (z = 0; z < sizeof(dev->dev_addr); z++)
		dev->dev_addr[z] = inb(dev->base_addr + MACADDRPROM + z);

	/* print config */

	printk(KERN_INFO "%s: IRQ %d, I/O %#lx, memory %#lx-%#lx, "
	       "MAC address %02x:%02x:%02x:%02x:%02x:%02x.\n",
	       dev->name, priv->realirq, dev->base_addr,
	       dev->mem_start, dev->mem_end - 1,
	       dev->dev_addr[0], dev->dev_addr[1], dev->dev_addr[2],
	       dev->dev_addr[3], dev->dev_addr[4], dev->dev_addr[5]);
	printk(KERN_INFO "%s: %s medium\n", dev->name, MediaNames[priv->medium]);

	/* reset board */

	ResetBoard(dev);

	/* next probe will start at next slot */

	startslot = slot + 1;

	return 0;
}

/* ------------------------------------------------------------------------
 * modularization support
 * ------------------------------------------------------------------------ */

#ifdef MODULE

#define DEVMAX 5

static struct net_device *moddevs[DEVMAX];
static int irq;
static int io;

module_param(irq, int, 0);
module_param(io, int, 0);
MODULE_PARM_DESC(irq, "IBM LAN/A IRQ number");
MODULE_PARM_DESC(io, "IBM LAN/A I/O base address");
MODULE_LICENSE("GPL");

int init_module(void)
{
	int z;

	startslot = 0;
	for (z = 0; z < DEVMAX; z++) {
		struct net_device *dev = alloc_etherdev(sizeof(ibmlana_priv));
		if (!dev)
			break;
		dev->irq = irq;
		dev->base_addr = io;
		if (ibmlana_probe(dev)) {
			free_netdev(dev);
			break;
		}
		if (register_netdev(dev)) {
			ibmlana_priv *priv = netdev_priv(dev);
			release_region(dev->base_addr, IBM_LANA_IORANGE);
			mca_mark_as_unused(priv->slot);
			mca_set_adapter_name(priv->slot, "");
			mca_set_adapter_procfn(priv->slot, NULL, NULL);
			iounmap(priv->base);
			free_netdev(dev);
			break;
		}
		moddevs[z] = dev;
	}
	return (z > 0) ? 0 : -EIO;
}

void cleanup_module(void)
{
	int z;
	for (z = 0; z < DEVMAX; z++) {
		struct net_device *dev = moddevs[z];
		if (dev) {
			ibmlana_priv *priv = netdev_priv(dev);
			unregister_netdev(dev);
			/*DeinitBoard(dev); */
			release_region(dev->base_addr, IBM_LANA_IORANGE);
			mca_mark_as_unused(priv->slot);
			mca_set_adapter_name(priv->slot, "");
			mca_set_adapter_procfn(priv->slot, NULL, NULL);
			iounmap(priv->base);
			free_netdev(dev);
		}
	}
}
#endif				/* MODULE */