/*      $Id: com90xx.c,v 1.9 1998/03/21 18:02:51 alan Exp $

   Derived from the original arcnet.c,
   Written 1994-1996 by Avery Pennarun,
   which was in turn derived from skeleton.c by Donald Becker.

   **********************

   The original copyright of skeleton.c was as follows:

   skeleton.c Written 1993 by Donald Becker.
   Copyright 1993 United States Government as represented by the
   Director, National Security Agency.  This software may only be used
   and distributed according to the terms of the GNU Public License as
   modified by SRC, incorporated herein by reference.

   **********************

   For more details, see drivers/net/arcnet.c

   **********************
 */


#include <linux/module.h>
#include <linux/version.h>

#include <linux/kernel.h>
#include <linux/sched.h>
#include <linux/types.h>
#include <linux/fcntl.h>
#include <linux/interrupt.h>
#include <linux/ptrace.h>
#include <linux/ioport.h>
#include <linux/in.h>
#include <linux/malloc.h>
#include <linux/string.h>
#include <linux/timer.h>
#include <linux/errno.h>
#include <linux/delay.h>
#include <linux/netdevice.h>
#include <linux/if_arp.h>
#include <linux/etherdevice.h>
#include <linux/skbuff.h>
#include <linux/init.h>
#include <linux/if_arcnet.h>
#include <linux/arcdevice.h>

#include <asm/system.h>
#include <asm/bitops.h>
#include <asm/io.h>
#include <asm/dma.h>

#include <net/arp.h>

/**************************************************************************/

/* On a fast computer, the buffer copy from memory to the ARCnet card during
 * a transmit can hog the bus just a little too long.  SLOW_XMIT_COPY
 * replaces the fast memcpy() with a slower for() loop that seems to solve
 * my problems with ftape.
 *
 * Probably a better solution would be to use memcpy_toio (more portable
 * anyway) and modify that routine to support REALLY_SLOW_IO-style
 * defines; ARCnet probably is not the only driver that can screw up an
 * ftape DMA transfer.
 *
 * Turn this on if you have timing-sensitive DMA (ie. a tape drive) and
 * would like to sacrifice a little bit of network speed to reduce tape
 * write retries or some related problem.
 */
#undef SLOW_XMIT_COPY


/* Define this to speed up the autoprobe by assuming if only one io port and
 * shmem are left in the list at Stage 5, they must correspond to each
 * other.
 *
 * This is undefined by default because it might not always be true, and the
 * extra check makes the autoprobe even more careful.  Speed demons can turn
 * it on - I think it should be fine if you only have one ARCnet card
 * installed.
 *
 * If no ARCnet cards are installed, this delay never happens anyway and thus
 * the option has no effect.
 */
#undef FAST_PROBE


/* Internal function declarations */
#ifdef MODULE
static
#endif
int arc90xx_probe(struct device *dev);
static void arc90xx_rx(struct device *dev, int recbuf);
static int arc90xx_found(struct device *dev, int ioaddr, int airq, u_long shmem, int more);
static void arc90xx_inthandler(struct device *dev);
static int arc90xx_reset(struct device *dev, int reset_delay);
static void arc90xx_setmask(struct device *dev, u_char mask);
static void arc90xx_command(struct device *dev, u_char command);
static u_char arc90xx_status(struct device *dev);
static void arc90xx_prepare_tx(struct device *dev, u_char * hdr, int hdrlen,
	     char *data, int length, int daddr, int exceptA, int offset);
static void arc90xx_openclose(int open);


/* Module parameters */

#ifdef MODULE
static int io = 0x0;		/* <--- EDIT THESE LINES FOR YOUR CONFIGURATION */
static int irq = 0;		/* or use the insmod io= irq= shmem= options */
static int shmem = 0;
static char *device;		/* use eg. device="arc1" to change name */

MODULE_PARM(io, "i");
MODULE_PARM(irq, "i");
MODULE_PARM(shmem, "i");
MODULE_PARM(device, "s");
#else
__initfunc(void com90xx_setup(char *str, int *ints));
char __initdata com90xx_explicit = 0;

extern struct device arcnet_devs[];
extern char arcnet_dev_names[][10];
extern int arcnet_num_devs;
#endif


/* Handy defines for ARCnet specific stuff */

/* The number of low I/O ports used by the card. */
#define ARCNET_TOTAL_SIZE	16

/* COM 9026 controller chip --> ARCnet register addresses */
#define _INTMASK (ioaddr+0)	/* writable */
#define _STATUS  (ioaddr+0)	/* readable */
#define _COMMAND (ioaddr+1)	/* writable, returns random vals on read (?) */
#define _RESET  (ioaddr+8)	/* software reset (on read) */
#define _MEMDATA  (ioaddr+12)	/* Data port for IO-mapped memory */
#define _ADDR_HI  (ioaddr+15)	/* Control registers for said */
#define _ADDR_LO  (ioaddr+14)
#define _CONFIG  (ioaddr+2)	/* Configuration register */

#define RDDATAflag      0x00	/* Next access is a read/~write */

#define ARCSTATUS	inb(_STATUS)
#define ACOMMAND(cmd) 	outb((cmd),_COMMAND)
#define AINTMASK(msk)	outb((msk),_INTMASK)
#define SETCONF		outb(lp->config,_CONFIG)
#define ARCRESET	inb(_RESET)

static const char *version =
"com90xx.c: v3.00 97/11/09 Avery Pennarun <apenwarr@worldvisions.ca> et al.\n";


/****************************************************************************
 *                                                                          *
 * Probe and initialization                                                 *
 *                                                                          *
 ****************************************************************************/

/* Check for an ARCnet network adaptor, and return '0' if one exists.
 *  If dev->base_addr == 0, probe all likely locations.
 *  If dev->base_addr == 1, always return failure.
 *  If dev->base_addr == 2, allocate space for the device and return success
 *                          (detachable devices only).
 *
 * NOTE: the list of possible ports/shmems is static, so it is retained
 * across calls to arcnet_probe.  So, if more than one ARCnet probe is made,
 * values that were discarded once will not even be tried again.
 *
 * FIXME: grab all devices in one shot and eliminate the big static array.
 */

static int ports[(0x3f0 - 0x200) / 16 + 1] __initdata = {
	0
};
static u_long shmems[(0xFF800 - 0xA0000) / 2048 + 1] __initdata = {
	0
};

__initfunc(int arc90xx_probe(struct device *dev))
{
	static int init_once = 0;
	static int numports = sizeof(ports) / sizeof(ports[0]), numshmems = sizeof(shmems) / sizeof(shmems[0]);
	int count, status, delayval, ioaddr, numprint, airq, retval = -ENODEV,
	 openparen = 0;
	unsigned long airqmask;
	int *port;
	u_long *shmem;

	if (!init_once) {
		for (count = 0x200; count <= 0x3f0; count += 16)
			ports[(count - 0x200) / 16] = count;
		for (count = 0xA0000; count <= 0xFF800; count += 2048)
			shmems[(count - 0xA0000) / 2048] = count;
		BUGLVL(D_NORMAL) printk(version);
		BUGMSG(D_DURING, "space used for probe buffers: %d+%d=%d bytes\n",
		       sizeof(ports), sizeof(shmems),
		       sizeof(ports) + sizeof(shmems));
	}
	init_once++;

	BUGMSG(D_INIT, "given: base %lXh, IRQ %d, shmem %lXh\n",
	       dev->base_addr, dev->irq, dev->mem_start);

	if (dev->base_addr > 0x1ff) {	/* Check a single specified port */
		ports[0] = dev->base_addr;
		numports = 1;
	} else if (dev->base_addr > 0)	/* Don't probe at all. */
		return -ENXIO;

	if (dev->mem_start) {
		shmems[0] = dev->mem_start;
		numshmems = 1;
	}
	/* Stage 1: abandon any reserved ports, or ones with status==0xFF
	 * (empty), and reset any others by reading the reset port.
	 */
	BUGMSG(D_INIT, "Stage 1: ");
	numprint = 0;
	for (port = &ports[0]; port - ports < numports; port++) {
		numprint++;
		if (numprint > 8) {
			BUGMSG2(D_INIT, "\n");
			BUGMSG(D_INIT, "Stage 1: ");
			numprint = 1;
		}
		BUGMSG2(D_INIT, "%Xh ", *port);

		ioaddr = *port;

		if (check_region(*port, ARCNET_TOTAL_SIZE)) {
			BUGMSG2(D_INIT_REASONS, "(check_region)\n");
			BUGMSG(D_INIT_REASONS, "Stage 1: ");
			BUGLVL(D_INIT_REASONS) numprint = 0;
			*port = ports[numports - 1];
			numports--;
			port--;
			continue;
		}
		if (ARCSTATUS == 0xFF) {
			BUGMSG2(D_INIT_REASONS, "(empty)\n");
			BUGMSG(D_INIT_REASONS, "Stage 1: ");
			BUGLVL(D_INIT_REASONS) numprint = 0;
			*port = ports[numports - 1];
			numports--;
			port--;
			continue;
		}
		ARCRESET;	/* begin resetting card */

		BUGMSG2(D_INIT_REASONS, "\n");
		BUGMSG(D_INIT_REASONS, "Stage 1: ");
		BUGLVL(D_INIT_REASONS) numprint = 0;
	}
	BUGMSG2(D_INIT, "\n");

	if (!numports) {
		BUGMSG(D_NORMAL, "Stage 1: No ARCnet cards found.\n");
		return -ENODEV;
	}
	/* Stage 2: we have now reset any possible ARCnet cards, so we can't
	 * do anything until they finish.  If D_INIT, print the list of
	 * cards that are left.
	 */
	BUGMSG(D_INIT, "Stage 2: ");
	numprint = 0;
	for (port = &ports[0]; port - ports < numports; port++) {
		numprint++;
		if (numprint > 8) {
			BUGMSG2(D_INIT, "\n");
			BUGMSG(D_INIT, "Stage 2: ");
			numprint = 1;
		}
		BUGMSG2(D_INIT, "%Xh ", *port);
	}
	BUGMSG2(D_INIT, "\n");
	JIFFER(RESETtime);

	/* Stage 3: abandon any shmem addresses that don't have the signature
	 * 0xD1 byte in the right place, or are read-only.
	 */
	BUGMSG(D_INIT, "Stage 3: ");
	numprint = 0;
	for (shmem = &shmems[0]; shmem - shmems < numshmems; shmem++) {
		u_long ptr;

		numprint++;
		if (numprint > 8) {
			BUGMSG2(D_INIT, "\n");
			BUGMSG(D_INIT, "Stage 3: ");
			numprint = 1;
		}
		BUGMSG2(D_INIT, "%lXh ", *shmem);

		ptr = (u_long) (*shmem);

		if (readb(ptr) != TESTvalue) {
			BUGMSG2(D_INIT_REASONS, "(mem=%02Xh, not %02Xh)\n",
				readb(ptr), TESTvalue);
			BUGMSG(D_INIT_REASONS, "Stage 3: ");
			BUGLVL(D_INIT_REASONS) numprint = 0;
			*shmem = shmems[numshmems - 1];
			numshmems--;
			shmem--;
			continue;
		}
		/* By writing 0x42 to the TESTvalue location, we also make
		 * sure no "mirror" shmem areas show up - if they occur
		 * in another pass through this loop, they will be discarded
		 * because *cptr != TESTvalue.
		 */
		writeb(0x42, ptr);
		if (readb(ptr) != 0x42) {
			BUGMSG2(D_INIT_REASONS, "(read only)\n");
			BUGMSG(D_INIT_REASONS, "Stage 3: ");
			*shmem = shmems[numshmems - 1];
			numshmems--;
			shmem--;
			continue;
		}
		BUGMSG2(D_INIT_REASONS, "\n");
		BUGMSG(D_INIT_REASONS, "Stage 3: ");
		BUGLVL(D_INIT_REASONS) numprint = 0;
	}
	BUGMSG2(D_INIT, "\n");

	if (!numshmems) {
		BUGMSG(D_NORMAL, "Stage 3: No ARCnet cards found.\n");
		return -ENODEV;
	}
	/* Stage 4: something of a dummy, to report the shmems that are
	 * still possible after stage 3.
	 */
	BUGMSG(D_INIT, "Stage 4: ");
	numprint = 0;
	for (shmem = &shmems[0]; shmem - shmems < numshmems; shmem++) {
		numprint++;
		if (numprint > 8) {
			BUGMSG2(D_INIT, "\n");
			BUGMSG(D_INIT, "Stage 4: ");
			numprint = 1;
		}
		BUGMSG2(D_INIT, "%lXh ", *shmem);
	}
	BUGMSG2(D_INIT, "\n");

	/* Stage 5: for any ports that have the correct status, can disable
	 * the RESET flag, and (if no irq is given) generate an autoirq,
	 * register an ARCnet device.
	 *
	 * Currently, we can only register one device per probe, so quit
	 * after the first one is found.
	 */
	BUGMSG(D_INIT, "Stage 5: ");
	numprint = 0;
	for (port = &ports[0]; port - ports < numports; port++) {
		numprint++;
		if (numprint > 8) {
			BUGMSG2(D_INIT, "\n");
			BUGMSG(D_INIT, "Stage 5: ");
			numprint = 1;
		}
		BUGMSG2(D_INIT, "%Xh ", *port);

		ioaddr = *port;
		status = ARCSTATUS;

		if ((status & 0x9D)
		    != (NORXflag | RECONflag | TXFREEflag | RESETflag)) {
			BUGMSG2(D_INIT_REASONS, "(status=%Xh)\n", status);
			BUGMSG(D_INIT_REASONS, "Stage 5: ");
			BUGLVL(D_INIT_REASONS) numprint = 0;
			*port = ports[numports - 1];
			numports--;
			port--;
			continue;
		}
		ACOMMAND(CFLAGScmd | RESETclear | CONFIGclear);
		status = ARCSTATUS;
		if (status & RESETflag) {
			BUGMSG2(D_INIT_REASONS, " (eternal reset, status=%Xh)\n",
				status);
			BUGMSG(D_INIT_REASONS, "Stage 5: ");
			BUGLVL(D_INIT_REASONS) numprint = 0;
			*port = ports[numports - 1];
			numports--;
			port--;
			continue;
		}
		/* skip this completely if an IRQ was given, because maybe
		 * we're on a machine that locks during autoirq!
		 */
		if (!dev->irq) {
			/* if we do this, we're sure to get an IRQ since the
			 * card has just reset and the NORXflag is on until
			 * we tell it to start receiving.
			 */
			airqmask = probe_irq_on();
			AINTMASK(NORXflag);
			mdelay(1);
			AINTMASK(0);
			airq = probe_irq_off(airqmask);

			if (airq <= 0) {
				BUGMSG2(D_INIT_REASONS, "(airq=%d)\n", airq);
				BUGMSG(D_INIT_REASONS, "Stage 5: ");
				BUGLVL(D_INIT_REASONS) numprint = 0;
				*port = ports[numports - 1];
				numports--;
				port--;
				continue;
			}
		} else {
			airq = dev->irq;
		}

		BUGMSG2(D_INIT, "(%d,", airq);
		openparen = 1;

		/* Everything seems okay.  But which shmem, if any, puts
		 * back its signature byte when the card is reset?
		 *
		 * If there are multiple cards installed, there might be
		 * multiple shmems still in the list.
		 */
#ifdef FAST_PROBE
		if (numports > 1 || numshmems > 1) {
			ARCRESET;
			JIFFER(RESETtime);
		} else {
			/* just one shmem and port, assume they match */
			writeb(TESTvalue, shmems[0]);
		}
#else
		ARCRESET;
		JIFFER(RESETtime);
#endif

		for (shmem = &shmems[0]; shmem - shmems < numshmems; shmem++) {
			u_long ptr;
			ptr = (u_long) (*shmem);

			if (readb(ptr) == TESTvalue) {	/* found one */
				int probe_more;
				BUGMSG2(D_INIT, "%lXh)\n", *shmem);
				openparen = 0;

				/* register the card */
				if (init_once == 1 && numshmems > 1)
					probe_more = numshmems - 1;
				else
					probe_more = 0;
				retval = arc90xx_found(dev, *port, airq, *shmem, probe_more);
				if (retval)
					openparen = 0;

				/* remove shmem from the list */
				*shmem = shmems[numshmems - 1];
				numshmems--;

				break;
			} else {
				BUGMSG2(D_INIT_REASONS, "%Xh-", readb(ptr));
			}
		}

		if (openparen) {
			BUGMSG2(D_INIT, "no matching shmem)\n");
			BUGMSG(D_INIT_REASONS, "Stage 5: ");
			BUGLVL(D_INIT_REASONS) numprint = 0;
		}
		*port = ports[numports - 1];
		numports--;
		port--;

		if (!retval)
			break;
	}
	BUGMSG(D_INIT_REASONS, "\n");

	/* Now put back TESTvalue on all leftover shmems.
	 */
	for (shmem = &shmems[0]; shmem - shmems < numshmems; shmem++)
		writeb(TESTvalue, *shmem);

	if (retval)
		BUGMSG(D_NORMAL, "Stage 5: No ARCnet cards found.\n");
	return retval;
}

/* Set up the struct device associated with this card.  Called after
 * probing succeeds.
 */
__initfunc(static int arc90xx_found(struct device *dev, int ioaddr, int airq, u_long shmem, int more))
{
	struct arcnet_local *lp;
	u_long first_mirror, last_mirror;
	int mirror_size;

	/* reserve the irq */
	if (request_irq(airq, &arcnet_interrupt, 0, "arcnet (90xx)", dev)) {
		BUGMSG(D_NORMAL, "Can't get IRQ %d!\n", airq);
		return -ENODEV;
	}
	dev->irq = airq;

	/* reserve the I/O region - guaranteed to work by check_region */
	request_region(ioaddr, ARCNET_TOTAL_SIZE, "arcnet (90xx)");
	dev->base_addr = ioaddr;

	/* find the real shared memory start/end points, including mirrors */
#define BUFFER_SIZE (512)
#define MIRROR_SIZE (BUFFER_SIZE*4)

	/* guess the actual size of one "memory mirror" - the number of
	 * bytes between copies of the shared memory.  On most cards, it's
	 * 2k (or there are no mirrors at all) but on some, it's 4k.
	 */
	mirror_size = MIRROR_SIZE;
	if (readb(shmem) == TESTvalue
	    && readb(shmem - mirror_size) != TESTvalue
	    && readb(shmem - 2 * mirror_size) == TESTvalue)
		mirror_size *= 2;

	first_mirror = last_mirror = shmem;
	while (readb(first_mirror) == TESTvalue)
		first_mirror -= mirror_size;
	first_mirror += mirror_size;

	while (readb(last_mirror) == TESTvalue)
		last_mirror += mirror_size;
	last_mirror -= mirror_size;

	dev->mem_start = first_mirror;
	dev->mem_end = last_mirror + MIRROR_SIZE - 1;
	dev->rmem_start = dev->mem_start + BUFFER_SIZE * 0;
	dev->rmem_end = dev->mem_start + BUFFER_SIZE * 2 - 1;

	/* Initialize the rest of the device structure. */

	dev->priv = kmalloc(sizeof(struct arcnet_local), GFP_KERNEL);
	if (dev->priv == NULL) {
		free_irq(airq, dev);
		release_region(ioaddr, ARCNET_TOTAL_SIZE);
		return -ENOMEM;
	}
	memset(dev->priv, 0, sizeof(struct arcnet_local));
	lp = (struct arcnet_local *) (dev->priv);
	lp->card_type = ARC_90xx;
	lp->card_type_str = "COM 90xx";
	lp->arcnet_reset = arc90xx_reset;
	lp->asetmask = arc90xx_setmask;
	lp->astatus = arc90xx_status;
	lp->acommand = arc90xx_command;
	lp->openclose_device = arc90xx_openclose;
	lp->prepare_tx = arc90xx_prepare_tx;
	lp->inthandler = arc90xx_inthandler;

	/* Fill in the fields of the device structure with generic
	 * values.
	 */
	arcnet_setup(dev);

	/* And now fill particular fields with arcnet values */
	dev->mtu = 1500;	/* completely arbitrary - agrees with ether, though */
	dev->hard_header_len = sizeof(struct ClientData);
	lp->sequence = 1;
	lp->recbuf = 0;

	BUGMSG(D_DURING, "ClientData header size is %d.\n",
	       sizeof(struct ClientData));
	BUGMSG(D_DURING, "HardHeader size is %d.\n",
	       sizeof(struct archdr));

	/* get and check the station ID from offset 1 in shmem */
	lp->stationid = readb(first_mirror + 1);

	if (lp->stationid == 0)
		BUGMSG(D_NORMAL, "WARNING!  Station address 00 is reserved "
		       "for broadcasts!\n");
	else if (lp->stationid == 255)
		BUGMSG(D_NORMAL, "WARNING!  Station address FF may confuse "
		       "DOS networking programs!\n");
	dev->dev_addr[0] = lp->stationid;

	BUGMSG(D_NORMAL, "ARCnet COM90xx: station %02Xh found at %03lXh, IRQ %d, "
	       "ShMem %lXh (%ld*%xh).\n",
	       lp->stationid,
	       dev->base_addr, dev->irq, dev->mem_start,
	 (dev->mem_end - dev->mem_start + 1) / mirror_size, mirror_size);

	/* OK. We're finished. If there are probably other cards, add other
	 * COM90xx drivers to the device chain, so they get probed later.
	 */

#ifndef MODULE
	while (!com90xx_explicit && more--) {
		if (arcnet_num_devs < MAX_ARCNET_DEVS) {
			arcnet_devs[arcnet_num_devs].next = dev->next;
			dev->next = &arcnet_devs[arcnet_num_devs];
			dev = dev->next;
			dev->name = (char *) &arcnet_dev_names[arcnet_num_devs];
			arcnet_num_devs++;
		} else {
			BUGMSG(D_NORMAL, "Too many arcnet devices - no more will be probed for.\n");
			return 0;
		}
		arcnet_makename(dev->name);
		dev->init = arc90xx_probe;
	}
#endif

	return 0;
}


/* Do a hardware reset on the card, and set up necessary registers.

 * This should be called as little as possible, because it disrupts the
 * token on the network (causes a RECON) and requires a significant delay.
 *
 * However, it does make sure the card is in a defined state.
 */
int arc90xx_reset(struct device *dev, int reset_delay)
{
	struct arcnet_local *lp = (struct arcnet_local *) dev->priv;
	short ioaddr = dev->base_addr;
	int delayval, recbuf = lp->recbuf;

	if (reset_delay == 3) {
		ARCRESET;
		return 0;
	}
	/* no IRQ's, please! */
	lp->intmask = 0;
	SETMASK;

	BUGMSG(D_INIT, "Resetting %s (status=%Xh)\n",
	       dev->name, ARCSTATUS);

	if (reset_delay) {
		/* reset the card */
		ARCRESET;
		JIFFER(RESETtime);
	}
	ACOMMAND(CFLAGScmd | RESETclear);	/* clear flags & end reset */
	ACOMMAND(CFLAGScmd | CONFIGclear);

	/* verify that the ARCnet signature byte is present */
	if (readb(dev->mem_start) != TESTvalue) {
		BUGMSG(D_NORMAL, "reset failed: TESTvalue not present.\n");
		return 1;
	}
	/* clear out status variables */
	recbuf = lp->recbuf = 0;
	lp->txbuf = 2;

	/* enable extended (512-byte) packets */
	ACOMMAND(CONFIGcmd | EXTconf);

#ifndef SLOW_XMIT_COPY
	/* clean out all the memory to make debugging make more sense :) */
	BUGLVL(D_DURING)
	    memset_io(dev->mem_start, 0x42, 2048);
#endif

	/* and enable receive of our first packet to the first buffer */
	EnableReceiver();

	/* re-enable interrupts */
	lp->intmask |= NORXflag;
#ifdef DETECT_RECONFIGS
	lp->intmask |= RECONflag;
#endif
	SETMASK;

	/* done!  return success. */
	return 0;
}


static void arc90xx_openclose(int open)
{
	if (open)
		MOD_INC_USE_COUNT;
	else
		MOD_DEC_USE_COUNT;
}


static void arc90xx_setmask(struct device *dev, u_char mask)
{
	short ioaddr = dev->base_addr;

	AINTMASK(mask);
}


static u_char arc90xx_status(struct device *dev)
{
	short ioaddr = dev->base_addr;

	return ARCSTATUS;
}


static void arc90xx_command(struct device *dev, u_char cmd)
{
	short ioaddr = dev->base_addr;

	ACOMMAND(cmd);
}


/* The actual interrupt handler routine - handle various IRQ's generated
 * by the card.
 */
static void arc90xx_inthandler(struct device *dev)
{
	struct arcnet_local *lp = (struct arcnet_local *) dev->priv;
	int ioaddr = dev->base_addr, status, boguscount = 3, didsomething;

	AINTMASK(0);

	BUGMSG(D_DURING, "in arcnet_inthandler (status=%Xh, intmask=%Xh)\n",
	       ARCSTATUS, lp->intmask);

	do {
		status = ARCSTATUS;
		didsomething = 0;

		/* RESET flag was enabled - card is resetting and if RX
		 * is disabled, it's NOT because we just got a packet.
		 */
		if (status & RESETflag) {
			BUGMSG(D_NORMAL, "spurious reset (status=%Xh)\n",
			       status);
			arc90xx_reset(dev, 0);

			/* all other flag values are just garbage */
			break;
		}
		/* RX is inhibited - we must have received something. */
		if (status & lp->intmask & NORXflag) {
			int recbuf = lp->recbuf = !lp->recbuf;

			BUGMSG(D_DURING, "receive irq (status=%Xh)\n",
			       status);

			/* enable receive of our next packet */
			EnableReceiver();

			/* Got a packet. */
			arc90xx_rx(dev, !recbuf);

			didsomething++;
		}
		/* it can only be an xmit-done irq if we're xmitting :) */
		/*if (status&TXFREEflag && !lp->in_txhandler && lp->sending) */
		if (status & lp->intmask & TXFREEflag) {
			struct Outgoing *out = &(lp->outgoing);
			int was_sending = lp->sending;

			lp->intmask &= ~TXFREEflag;

			lp->in_txhandler++;
			if (was_sending)
				lp->sending--;

			BUGMSG(D_DURING, "TX IRQ (stat=%Xh, numsegs=%d, segnum=%d, skb=%ph)\n",
			    status, out->numsegs, out->segnum, out->skb);

			if (was_sending && !(status & TXACKflag)) {
				if (lp->lasttrans_dest != 0) {
					BUGMSG(D_EXTRA, "transmit was not acknowledged! (status=%Xh, dest=%02Xh)\n",
					     status, lp->lasttrans_dest);
					lp->stats.tx_errors++;
					lp->stats.tx_carrier_errors++;
				} else {
					BUGMSG(D_DURING, "broadcast was not acknowledged; that's normal (status=%Xh, dest=%02Xh)\n",
					       status,
					       lp->lasttrans_dest);
				}
			}
			/* send packet if there is one */
			arcnet_go_tx(dev, 0);
			didsomething++;

			if (lp->intx) {
				BUGMSG(D_DURING, "TXDONE while intx! (status=%Xh, intx=%d)\n",
				       ARCSTATUS, lp->intx);
				lp->in_txhandler--;
				continue;
			}
			if (!lp->outgoing.skb) {
				BUGMSG(D_DURING, "TX IRQ done: no split to continue.\n");

				/* inform upper layers */
				if (!lp->txready)
					arcnet_tx_done(dev, lp);
				lp->in_txhandler--;
				continue;
			}
			/* if more than one segment, and not all segments
			 * are done, then continue xmit.
			 */
			if (out->segnum < out->numsegs)
				arcnetA_continue_tx(dev);
			arcnet_go_tx(dev, 0);

			/* if segnum==numsegs, the transmission is finished;
			 * free the skb.
			 */
			if (out->segnum >= out->numsegs) {
				/* transmit completed */
				out->segnum++;
				if (out->skb) {
					lp->stats.tx_bytes += out->skb->len;
					dev_kfree_skb(out->skb);
				}
				out->skb = NULL;

				/* inform upper layers */
				if (!lp->txready)
					arcnet_tx_done(dev, lp);
			}
			didsomething++;

			lp->in_txhandler--;
		} else if (lp->txready && !lp->sending && !lp->intx) {
			BUGMSG(D_NORMAL, "recovery from silent TX (status=%Xh)\n",
			       status);
			arcnet_go_tx(dev, 0);
			didsomething++;
		}
#ifdef DETECT_RECONFIGS
		if (status & (lp->intmask) & RECONflag) {
			ACOMMAND(CFLAGScmd | CONFIGclear);
			lp->stats.tx_carrier_errors++;

#ifdef SHOW_RECONFIGS
			BUGMSG(D_NORMAL, "Network reconfiguration detected (status=%Xh)\n",
			       status);
#endif				/* SHOW_RECONFIGS */

#ifdef RECON_THRESHOLD
			/* is the RECON info empty or old? */
			if (!lp->first_recon || !lp->last_recon ||
			    jiffies - lp->last_recon > HZ * 10) {
				if (lp->network_down)
					BUGMSG(D_NORMAL, "reconfiguration detected: cabling restored?\n");
				lp->first_recon = lp->last_recon = jiffies;
				lp->num_recons = lp->network_down = 0;

				BUGMSG(D_DURING, "recon: clearing counters.\n");
			} else {	/* add to current RECON counter */
				lp->last_recon = jiffies;
				lp->num_recons++;

				BUGMSG(D_DURING, "recon: counter=%d, time=%lds, net=%d\n",
				       lp->num_recons,
				 (lp->last_recon - lp->first_recon) / HZ,
				       lp->network_down);

				/* if network is marked up;
				 * and first_recon and last_recon are 60+ sec
				 *   apart;
				 * and the average no. of recons counted is
				 *   > RECON_THRESHOLD/min;
				 * then print a warning message.
				 */
				if (!lp->network_down
				    && (lp->last_recon - lp->first_recon) <= HZ * 60
				  && lp->num_recons >= RECON_THRESHOLD) {
					lp->network_down = 1;
					BUGMSG(D_NORMAL, "many reconfigurations detected: cabling problem?\n");
				} else if (!lp->network_down
					   && lp->last_recon - lp->first_recon > HZ * 60) {
					/* reset counters if we've gone for
					 * over a minute.
					 */
					lp->first_recon = lp->last_recon;
					lp->num_recons = 1;
				}
			}
		} else if (lp->network_down && jiffies - lp->last_recon > HZ * 10) {
			if (lp->network_down)
				BUGMSG(D_NORMAL, "cabling restored?\n");
			lp->first_recon = lp->last_recon = 0;
			lp->num_recons = lp->network_down = 0;

			BUGMSG(D_DURING, "not recon: clearing counters anyway.\n");
#endif
		}
#endif				/* DETECT_RECONFIGS */
	} while (--boguscount && didsomething);

	BUGMSG(D_DURING, "net_interrupt complete (status=%Xh, count=%d)\n",
	       ARCSTATUS, boguscount);
	BUGMSG(D_DURING, "\n");

	SETMASK;		/* put back interrupt mask */
}


/* A packet has arrived; grab it from the buffers and pass it to the generic
 * arcnet_rx routing to deal with it.
 */

static void arc90xx_rx(struct device *dev, int recbuf)
{
	struct arcnet_local *lp = (struct arcnet_local *) dev->priv;
	int ioaddr = dev->base_addr;
	union ArcPacket *arcpacket =
	(union ArcPacket *) phys_to_virt(dev->mem_start + recbuf * 512);
	u_char *arcsoft;
	short length, offset;
	u_char daddr, saddr;

	lp->stats.rx_packets++;

	saddr = arcpacket->hardheader.source;

	/* if source is 0, it's a "used" packet! */
	if (saddr == 0) {
		BUGMSG(D_NORMAL, "discarding old packet. (status=%Xh)\n",
		       ARCSTATUS);
		lp->stats.rx_errors++;
		return;
	}
	/* Set source address to zero to mark it as old */

	arcpacket->hardheader.source = 0;

	daddr = arcpacket->hardheader.destination;

	if (arcpacket->hardheader.offset1) {	/* Normal Packet */
		offset = arcpacket->hardheader.offset1;
		arcsoft = &arcpacket->raw[offset];
		length = 256 - offset;
	} else {		/* ExtendedPacket or ExceptionPacket */
		offset = arcpacket->hardheader.offset2;
		arcsoft = &arcpacket->raw[offset];

		length = 512 - offset;
	}

	arcnet_rx(lp, arcsoft, length, saddr, daddr);

	BUGLVL(D_RX) arcnet_dump_packet(lp->adev, arcpacket->raw, length > 240, "rx");

#ifndef SLOW_XMIT_COPY
	/* clean out the page to make debugging make more sense :) */
	BUGLVL(D_DURING)
	    memset((void *) arcpacket->raw, 0x42, 512);
#endif
}


/* Given an skb, copy a packet into the ARCnet buffers for later transmission
 * by arcnet_go_tx.
 */
static void arc90xx_prepare_tx(struct device *dev, u_char * hdr, int hdrlen,
	      char *data, int length, int daddr, int exceptA, int offset)
{
	struct arcnet_local *lp = (struct arcnet_local *) dev->priv;
	union ArcPacket *arcpacket =
	(union ArcPacket *) phys_to_virt(dev->mem_start + 512 * (lp->txbuf ^ 1));

#ifdef SLOW_XMIT_COPY
	char *iptr, *iend, *optr;
#endif

	lp->txbuf = lp->txbuf ^ 1;	/* XOR with 1 to alternate between 2 and 3 */

	length += hdrlen;

	BUGMSG(D_TX, "arcnetAS_prep_tx: hdr:%ph, length:%d, data:%ph\n",
	       hdr, length, data);

#ifndef SLOW_XMIT_COPY
	/* clean out the page to make debugging make more sense :) */
	BUGLVL(D_DURING)
	    memset_io(dev->mem_start + lp->txbuf * 512, 0x42, 512);
#endif

	arcpacket->hardheader.destination = daddr;

	/* load packet into shared memory */
	if (length <= MTU)	/* Normal (256-byte) Packet */
		arcpacket->hardheader.offset1 = offset = offset ? offset : 256 - length;

	else if (length >= MinTU || offset) {	/* Extended (512-byte) Packet */
		arcpacket->hardheader.offset1 = 0;
		arcpacket->hardheader.offset2 = offset = offset ? offset : 512 - length;
	} else if (exceptA) {	/* RFC1201 Exception Packet */
		arcpacket->hardheader.offset1 = 0;
		arcpacket->hardheader.offset2 = offset = 512 - length - 4;

		/* exception-specific stuff - these four bytes
		 * make the packet long enough to fit in a 512-byte
		 * frame.
		 */

		arcpacket->raw[offset + 0] = hdr[0];
		arcpacket->raw[offset + 1] = 0xFF;	/* FF flag */
		arcpacket->raw[offset + 2] = 0xFF;	/* FF padding */
		arcpacket->raw[offset + 3] = 0xFF;	/* FF padding */
		offset += 4;
	} else {		/* "other" Exception packet */
		/* RFC1051 - set 4 trailing bytes to 0 */
		memset(&arcpacket->raw[508], 0, 4);

		/* now round up to MinTU */
		arcpacket->hardheader.offset1 = 0;
		arcpacket->hardheader.offset2 = offset = 512 - MinTU;
	}

	/* copy the packet into ARCnet shmem
	 *  - the first bytes of ClientData header are skipped
	 */

	memcpy((u_char *) arcpacket + offset, (u_char *) hdr, hdrlen);
#ifdef SLOW_XMIT_COPY
	for (iptr = data, iend = iptr + length - hdrlen, optr = (char *) arcpacket + offset + hdrlen;
	     iptr < iend; iptr++, optr++) {
		*optr = *iptr;
		/*udelay(5); */
	}
#else
	memcpy((u_char *) arcpacket + offset + hdrlen, data, length - hdrlen);
#endif

	BUGMSG(D_DURING, "transmitting packet to station %02Xh (%d bytes)\n",
	       daddr, length);

	BUGLVL(D_TX) arcnet_dump_packet(dev, arcpacket->raw, length > MTU, "tx");

	lp->lastload_dest = daddr;
	lp->txready = lp->txbuf;	/* packet is ready for sending */
}


/****************************************************************************
 *                                                                          *
 * Kernel Loadable Module Support                                           *
 *                                                                          *
 ****************************************************************************/


#ifdef MODULE

static char devicename[9] = "";
static struct device thiscard =
{
	devicename,		/* device name is inserted by linux/drivers/net/net_init.c */
	0, 0, 0, 0,
	0, 0,			/* I/O address, IRQ */
	0, 0, 0, NULL, arc90xx_probe
};


int init_module(void)
{
	struct device *dev = &thiscard;
	if (device)
		strcpy(dev->name, device);
	else
		arcnet_makename(dev->name);

	dev->base_addr = io;

	dev->irq = irq;
	if (dev->irq == 2)
		dev->irq = 9;

	if (shmem) {
		dev->mem_start = shmem;
		dev->mem_end = thiscard.mem_start + 512 * 4 - 1;
		dev->rmem_start = thiscard.mem_start + 512 * 0;
		dev->rmem_end = thiscard.mem_start + 512 * 2 - 1;
	}
	if (register_netdev(dev) != 0)
		return -EIO;
	arcnet_use_count(1);
	return 0;
}

void cleanup_module(void)
{
	struct device *dev = &thiscard;
	int ioaddr = dev->mem_start;

	if (dev->start)
		(*dev->stop) (dev);

	/* Flush TX and disable RX */
	if (ioaddr) {
		AINTMASK(0);	/* disable IRQ's */
		ACOMMAND(NOTXcmd);	/* stop transmit */
		ACOMMAND(NORXcmd);	/* disable receive */

#if defined(IO_MAPPED_BUFFERS) && !defined(COM20020)
		/* Set the thing back to MMAP mode, in case the old
		   driver is loaded later */
		outb((inb(_CONFIG) & ~IOMAPflag), _CONFIG);
#endif
	}
	if (dev->irq) {
		free_irq(dev->irq, dev);
	}
	if (dev->base_addr)
		release_region(dev->base_addr, ARCNET_TOTAL_SIZE);
	unregister_netdev(dev);
	kfree(dev->priv);
	dev->priv = NULL;
	arcnet_use_count(0);
}

#else

__initfunc(void com90xx_setup(char *str, int *ints))
{
	struct device *dev;

	if (arcnet_num_devs == MAX_ARCNET_DEVS) {
		printk("com90xx: Too many ARCnet devices registered (max %d).\n",
		       MAX_ARCNET_DEVS);
		return;
	}
	if (!ints[0] && (!str || !*str)) {
		printk("com90xx: Disabled.\n");
		com90xx_explicit++;
		return;
	}
	dev = &arcnet_devs[arcnet_num_devs];

	dev->dev_addr[3] = 3;
	dev->init = arc90xx_probe;

	switch (ints[0]) {
	case 4:		/* ERROR */
		printk("com20020: Too many arguments.\n");

	case 3:		/* Mem address */
		dev->mem_start = ints[3];

	case 2:		/* IRQ */
		dev->irq = ints[2];

	case 1:		/* IO address */
		dev->base_addr = ints[1];
	}

	dev->name = (char *) &arcnet_dev_names[arcnet_num_devs];

	if (str)
		strncpy(dev->name, str, 9);

	arcnet_num_devs++;
}
#endif				/* MODULE */
