/* atp.c: Attached (pocket) ethernet adapter driver for linux. */
/*
	This is a driver for a commonly OEMed pocket (parallel port)
	ethernet adapter.  

	Written 1993,1994,1995 by Donald Becker.

	Copyright 1993 United States Government as represented by the
	Director, National Security Agency.

	This software may be used and distributed according to the terms
	of the GNU Public License, incorporated herein by reference.

	The author may be reached as becker@CESDIS.gsfc.nasa.gov, or C/O
	Center of Excellence in Space Data and Information Sciences
		Code 930.5, Goddard Space Flight Center, Greenbelt MD 20771

	The timer-based reset code was written by Bill Carlson, wwc@super.org.
*/

static const char *version =
	"atp.c:v1.01 1/18/95 Donald Becker (becker@cesdis.gsfc.nasa.gov)\n";

/*
	This file is a device driver for the RealTek (aka AT-Lan-Tec) pocket
	ethernet adapter.  This is a common low-cost OEM pocket ethernet
	adapter, sold under many names.

  Sources:
	This driver was written from the packet driver assembly code provided by
	Vincent Bono of AT-Lan-Tec.	 Ever try to figure out how a complicated
	device works just from the assembly code?  It ain't pretty.  The following
	description is written based on guesses and writing lots of special-purpose
	code to test my theorized operation.

					Theory of Operation
	
	The RTL8002 adapter seems to be built around a custom spin of the SEEQ
	controller core.  It probably has a 16K or 64K internal packet buffer, of
	which the first 4K is devoted to transmit and the rest to receive.
	The controller maintains the queue of received packet and the packet buffer
	access pointer internally, with only 'reset to beginning' and 'skip to next
	packet' commands visible.  The transmit packet queue holds two (or more?)
	packets: both 'retransmit this packet' (due to collision) and 'transmit next
	packet' commands must be started by hand.

	The station address is stored in a standard bit-serial EEPROM which must be
	read (ughh) by the device driver.  (Provisions have been made for
	substituting a 74S288 PROM, but I haven't gotten reports of any models
	using it.)  Unlike built-in devices, a pocket adapter can temporarily lose
	power without indication to the device driver.  The major effect is that
	the station address, receive filter (promiscuous, etc.) and transceiver
	must be reset.

	The controller itself has 16 registers, some of which use only the lower
	bits.  The registers are read and written 4 bits at a time.  The four bit
	register address is presented on the data lines along with a few additional
	timing and control bits.  The data is then read from status port or written
	to the data port.

	Since the bulk data transfer of the actual packets through the slow
	parallel port dominates the driver's running time, four distinct data
	(non-register) transfer modes are provided by the adapter, two in each
	direction.  In the first mode timing for the nibble transfers is
	provided through the data port.  In the second mode the same timing is
	provided through the control port.  In either case the data is read from
	the status port and written to the data port, just as it is accessing
	registers.

	In addition to the basic data transfer methods, several more are modes are
	created by adding some delay by doing multiple reads of the data to allow
	it to stabilize.  This delay seems to be needed on most machines.

	The data transfer mode is stored in the 'dev->if_port' field.  Its default
	value is '4'.  It may be overridden at boot-time using the third parameter
	to the "ether=..." initialization.

	The header file <atp.h> provides inline functions that encapsulate the
	register and data access methods.  These functions are hand-tuned to
	generate reasonable object code.  This header file also documents my
	interpretations of the device registers.
*/

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

#include <linux/netdevice.h>
#include <linux/etherdevice.h>
#include <linux/skbuff.h>

#include "atp.h"

/* use 0 for production, 1 for verification, >2 for debug */
#ifndef NET_DEBUG
#define NET_DEBUG 1
#endif
static unsigned int net_debug = NET_DEBUG;

/* The number of low I/O ports used by the ethercard. */
#define ETHERCARD_TOTAL_SIZE	3

/* This code, written by wwc@super.org, resets the adapter every
   TIMED_CHECKER ticks.  This recovers from an unknown error which
   hangs the device. */
#define TIMED_CHECKER (HZ/4)
#ifdef TIMED_CHECKER
#include <linux/timer.h>
static void atp_timed_checker(unsigned long ignored);
static struct device *atp_timed_dev;
static struct timer_list atp_timer = {NULL, NULL, 0, 0, atp_timed_checker};
#endif

/* Index to functions, as function prototypes. */

extern int atp_probe(struct device *dev);

static int atp_probe1(struct device *dev, short ioaddr);
static void get_node_ID(struct device *dev);
static unsigned short eeprom_op(short ioaddr, unsigned int cmd);
static int net_open(struct device *dev);
static void hardware_init(struct device *dev);
static void write_packet(short ioaddr, int length, unsigned char *packet, int mode);
static void trigger_send(short ioaddr, int length);
static int	net_send_packet(struct sk_buff *skb, struct device *dev);
static void net_interrupt(int irq, void *dev_id, struct pt_regs *regs);
static void net_rx(struct device *dev);
static void read_block(short ioaddr, int length, unsigned char *buffer, int data_mode);
static int net_close(struct device *dev);
static struct net_device_stats *net_get_stats(struct device *dev);
static void set_multicast_list(struct device *dev);


/* Check for a network adapter of this type, and return '0' iff 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).
   */
__initfunc(int
atp_init(struct device *dev))
{
	int *port, ports[] = {0x378, 0x278, 0x3bc, 0};
	int base_addr = dev->base_addr;

	if (base_addr > 0x1ff)		/* Check a single specified location. */
		return atp_probe1(dev, base_addr);
	else if (base_addr == 1)	/* Don't probe at all. */
		return ENXIO;

	for (port = ports; *port; port++) {
		int ioaddr = *port;
		outb(0x57, ioaddr + PAR_DATA);
		if (inb(ioaddr + PAR_DATA) != 0x57)
			continue;
		if (atp_probe1(dev, ioaddr) == 0)
			return 0;
	}

	return ENODEV;
}

__initfunc(static int atp_probe1(struct device *dev, short ioaddr))
{
	int saved_ctrl_reg, status;

	outb(0xff, ioaddr + PAR_DATA);
	/* Save the original value of the Control register, in case we guessed
	   wrong. */
	saved_ctrl_reg = inb(ioaddr + PAR_CONTROL);
	/* IRQEN=0, SLCTB=high INITB=high, AUTOFDB=high, STBB=high. */
	outb(0x04, ioaddr + PAR_CONTROL);
	write_reg_high(ioaddr, CMR1, CMR1h_RESET);
	eeprom_delay(2048);
	status = read_nibble(ioaddr, CMR1);

	if ((status & 0x78) != 0x08) {
		/* The pocket adapter probe failed, restore the control register. */
		outb(saved_ctrl_reg, ioaddr + PAR_CONTROL);
		return 1;
	}
	status = read_nibble(ioaddr, CMR2_h);
	if ((status & 0x78) != 0x10) {
		outb(saved_ctrl_reg, ioaddr + PAR_CONTROL);
		return 1;
	}
	/* Find the IRQ used by triggering an interrupt. */
	write_reg_byte(ioaddr, CMR2, 0x01);			/* No accept mode, IRQ out. */
	write_reg_high(ioaddr, CMR1, CMR1h_RxENABLE | CMR1h_TxENABLE);	/* Enable Tx and Rx. */

	/* Omit autoIRQ routine for now. Use "table lookup" instead.  Uhgggh. */
	if (ioaddr == 0x378)
		dev->irq = 7;
	else
		dev->irq = 5;
	write_reg_high(ioaddr, CMR1, CMR1h_TxRxOFF); /* Disable Tx and Rx units. */
	write_reg(ioaddr, CMR2, CMR2_NULL);

	dev->base_addr = ioaddr;

	/* Read the station address PROM.  */
	get_node_ID(dev);

	printk("%s: Pocket adapter found at %#3lx, IRQ %d, SAPROM "
		   "%02X:%02X:%02X:%02X:%02X:%02X.\n", dev->name, dev->base_addr,
		   dev->irq, dev->dev_addr[0], dev->dev_addr[1], dev->dev_addr[2],
		   dev->dev_addr[3], dev->dev_addr[4], dev->dev_addr[5]);

	/* Leave the hardware in a reset state. */
    write_reg_high(ioaddr, CMR1, CMR1h_RESET);

	if (net_debug)
		printk(version);

	/* Initialize the device structure. */
	ether_setup(dev);
	dev->priv = kmalloc(sizeof(struct net_local), GFP_KERNEL);
	if (dev->priv == NULL)
		return -ENOMEM;
	memset(dev->priv, 0, sizeof(struct net_local));


	{
		struct net_local *lp = (struct net_local *)dev->priv;
		lp->addr_mode = CMR2h_Normal;
	}

	/* For the ATP adapter the "if_port" is really the data transfer mode. */
	dev->if_port = (dev->mem_start & 0xf) ? dev->mem_start & 0x7 : 4;
	if (dev->mem_end & 0xf)
		net_debug = dev->mem_end & 7;

	dev->open		= net_open;
	dev->stop		= net_close;
	dev->hard_start_xmit = net_send_packet;
	dev->get_stats	= net_get_stats;
	dev->set_multicast_list = &set_multicast_list;

#ifdef TIMED_CHECKER
	del_timer(&atp_timer);
	atp_timer.expires = jiffies + TIMED_CHECKER;
	atp_timed_dev = dev;
	add_timer(&atp_timer);
#endif
	return 0;
}

/* Read the station address PROM, usually a word-wide EEPROM. */
__initfunc(static void get_node_ID(struct device *dev))
{
	short ioaddr = dev->base_addr;
	int sa_offset = 0;
	int i;
	
	write_reg(ioaddr, CMR2, CMR2_EEPROM);	  /* Point to the EEPROM control registers. */
	
	/* Some adapters have the station address at offset 15 instead of offset
	   zero.  Check for it, and fix it if needed. */
	if (eeprom_op(ioaddr, EE_READ(0)) == 0xffff)
		sa_offset = 15;
	
	for (i = 0; i < 3; i++)
		((unsigned short *)dev->dev_addr)[i] =
			ntohs(eeprom_op(ioaddr, EE_READ(sa_offset + i)));
	
	write_reg(ioaddr, CMR2, CMR2_NULL);
}

/*
  An EEPROM read command starts by shifting out 0x60+address, and then
  shifting in the serial data. See the NatSemi databook for details.
 *		   ________________
 * CS : __|
 *			   ___	   ___
 * CLK: ______|	  |___|	  |
 *		 __ _______ _______
 * DI :	 __X_______X_______X
 * DO :	 _________X_______X
 */

__initfunc(static unsigned short eeprom_op(short ioaddr, unsigned int cmd))
{
	unsigned eedata_out = 0;
	int num_bits = EE_CMD_SIZE;
	
	while (--num_bits >= 0) {
		char outval = test_bit(num_bits, &cmd) ? EE_DATA_WRITE : 0;
		write_reg_high(ioaddr, PROM_CMD, outval | EE_CLK_LOW);
		eeprom_delay(5);
		write_reg_high(ioaddr, PROM_CMD, outval | EE_CLK_HIGH);
		eedata_out <<= 1;
		if (read_nibble(ioaddr, PROM_DATA) & EE_DATA_READ)
			eedata_out++;
		eeprom_delay(5);
	}
	write_reg_high(ioaddr, PROM_CMD, EE_CLK_LOW & ~EE_CS);
	return eedata_out;
}


/* Open/initialize the board.  This is called (in the current kernel)
   sometime after booting when the 'ifconfig' program is run.

   This routine sets everything up anew at each open, even
   registers that "should" only need to be set once at boot, so that
   there is non-reboot way to recover if something goes wrong.

   This is an attachable device: if there is no dev->priv entry then it wasn't
   probed for at boot-time, and we need to probe for it again.
   */
static int net_open(struct device *dev)
{

	/* The interrupt line is turned off (tri-stated) when the device isn't in
	   use.  That's especially important for "attached" interfaces where the
	   port or interrupt may be shared. */
	if (request_irq(dev->irq, &net_interrupt, 0, "ATP", dev)) {
		return -EAGAIN;
	}

	hardware_init(dev);
	dev->start = 1;
	return 0;
}

/* This routine resets the hardware.  We initialize everything, assuming that
   the hardware may have been temporarily detached. */
static void hardware_init(struct device *dev)
{
	struct net_local *lp = (struct net_local *)dev->priv;
	int ioaddr = dev->base_addr;
    int i;

	write_reg_high(ioaddr, CMR1, CMR1h_RESET);
	
    for (i = 0; i < 6; i++)
		write_reg_byte(ioaddr, PAR0 + i, dev->dev_addr[i]);

	write_reg_high(ioaddr, CMR2, lp->addr_mode);

	if (net_debug > 2) {
		printk("%s: Reset: current Rx mode %d.\n", dev->name,
			   (read_nibble(ioaddr, CMR2_h) >> 3) & 0x0f);
	}

    write_reg(ioaddr, CMR2, CMR2_IRQOUT);
    write_reg_high(ioaddr, CMR1, CMR1h_RxENABLE | CMR1h_TxENABLE);

	/* Enable the interrupt line from the serial port. */
	outb(Ctrl_SelData + Ctrl_IRQEN, ioaddr + PAR_CONTROL);

	/* Unmask the interesting interrupts. */
    write_reg(ioaddr, IMR, ISR_RxOK | ISR_TxErr | ISR_TxOK);
    write_reg_high(ioaddr, IMR, ISRh_RxErr);

	lp->tx_unit_busy = 0;
    lp->pac_cnt_in_tx_buf = 0;
	lp->saved_tx_size = 0;

	dev->tbusy = 0;
	dev->interrupt = 0;
}

static void trigger_send(short ioaddr, int length)
{
	write_reg_byte(ioaddr, TxCNT0, length & 0xff);
	write_reg(ioaddr, TxCNT1, length >> 8);
	write_reg(ioaddr, CMR1, CMR1_Xmit);
}

static void write_packet(short ioaddr, int length, unsigned char *packet, int data_mode)
{
    length = (length + 1) & ~1;		/* Round up to word length. */
    outb(EOC+MAR, ioaddr + PAR_DATA);
    if ((data_mode & 1) == 0) {
		/* Write the packet out, starting with the write addr. */
		outb(WrAddr+MAR, ioaddr + PAR_DATA);
		do {
			write_byte_mode0(ioaddr, *packet++);
		} while (--length > 0) ;
    } else {
		/* Write the packet out in slow mode. */
		unsigned char outbyte = *packet++;

		outb(Ctrl_LNibWrite + Ctrl_IRQEN, ioaddr + PAR_CONTROL);
		outb(WrAddr+MAR, ioaddr + PAR_DATA);

		outb((outbyte & 0x0f)|0x40, ioaddr + PAR_DATA);
		outb(outbyte & 0x0f, ioaddr + PAR_DATA);
		outbyte >>= 4;
		outb(outbyte & 0x0f, ioaddr + PAR_DATA);
		outb(Ctrl_HNibWrite + Ctrl_IRQEN, ioaddr + PAR_CONTROL);
		while (--length > 0)
			write_byte_mode1(ioaddr, *packet++);
    }
    /* Terminate the Tx frame.  End of write: ECB. */
    outb(0xff, ioaddr + PAR_DATA);
    outb(Ctrl_HNibWrite | Ctrl_SelData | Ctrl_IRQEN, ioaddr + PAR_CONTROL);
}

static int
net_send_packet(struct sk_buff *skb, struct device *dev)
{
	struct net_local *lp = (struct net_local *)dev->priv;
	int ioaddr = dev->base_addr;

	if (dev->tbusy) {
		/* If we get here, some higher level has decided we are broken.
		   There should really be a "kick me" function call instead. */
		int tickssofar = jiffies - dev->trans_start;
		if (tickssofar < 5)
			return 1;
		printk("%s: transmit timed out, %s?\n", dev->name,
			   inb(ioaddr + PAR_CONTROL) & 0x10 ? "network cable problem"
			   :  "IRQ conflict");
		lp->stats.tx_errors++;
		/* Try to restart the adapter. */
		hardware_init(dev);
		dev->tbusy=0;
		dev->trans_start = jiffies;
	}

	/* Block a timer-based transmit from overlapping.  This could better be
	   done with atomic_swap(1, dev->tbusy), but set_bit() works as well. */
	if (test_and_set_bit(0, (void*)&dev->tbusy) != 0)
		printk("%s: Transmitter access conflict.\n", dev->name);
	else {
		short length = ETH_ZLEN < skb->len ? skb->len : ETH_ZLEN;
		unsigned char *buf = skb->data;
		int flags;

		/* Disable interrupts by writing 0x00 to the Interrupt Mask Register.
		   This sequence must not be interrupted by an incoming packet. */
		save_flags(flags);
		cli();
		write_reg(ioaddr, IMR, 0);
		write_reg_high(ioaddr, IMR, 0);
		restore_flags(flags);

		write_packet(ioaddr, length, buf, dev->if_port);

		lp->pac_cnt_in_tx_buf++;
		if (lp->tx_unit_busy == 0) {
			trigger_send(ioaddr, length);
			lp->saved_tx_size = 0; 				/* Redundant */
			lp->re_tx = 0;
			lp->tx_unit_busy = 1;
		} else
			lp->saved_tx_size = length;

		dev->trans_start = jiffies;
		/* Re-enable the LPT interrupts. */
		write_reg(ioaddr, IMR, ISR_RxOK | ISR_TxErr | ISR_TxOK);
		write_reg_high(ioaddr, IMR, ISRh_RxErr);
	}

	dev_kfree_skb (skb);

	return 0;
}

/* The typical workload of the driver:
   Handle the network interface interrupts. */
static void
net_interrupt(int irq, void *dev_id, struct pt_regs * regs)
{
	struct device *dev = dev_id;
	struct net_local *lp;
	int ioaddr, status, boguscount = 20;
	static int num_tx_since_rx = 0;

	if (dev == NULL) {
		printk ("ATP_interrupt(): irq %d for unknown device.\n", irq);
		return;
	}
	dev->interrupt = 1;

	ioaddr = dev->base_addr;
	lp = (struct net_local *)dev->priv;

	/* Disable additional spurious interrupts. */
	outb(Ctrl_SelData, ioaddr + PAR_CONTROL);

	/* The adapter's output is currently the IRQ line, switch it to data. */
	write_reg(ioaddr, CMR2, CMR2_NULL);
	write_reg(ioaddr, IMR, 0);

	if (net_debug > 5) printk("%s: In interrupt ", dev->name);
    while (--boguscount > 0) {
		status = read_nibble(ioaddr, ISR);
		if (net_debug > 5) printk("loop status %02x..", status);

		if (status & (ISR_RxOK<<3)) {
			write_reg(ioaddr, ISR, ISR_RxOK); /* Clear the Rx interrupt. */
			do {
				int read_status = read_nibble(ioaddr, CMR1);
				if (net_debug > 6)
					printk("handling Rx packet %02x..", read_status);
				/* We acknowledged the normal Rx interrupt, so if the interrupt
				   is still outstanding we must have a Rx error. */
				if (read_status & (CMR1_IRQ << 3)) { /* Overrun. */
					lp->stats.rx_over_errors++;
					/* Set to no-accept mode long enough to remove a packet. */
					write_reg_high(ioaddr, CMR2, CMR2h_OFF);
					net_rx(dev);
					/* Clear the interrupt and return to normal Rx mode. */
					write_reg_high(ioaddr, ISR, ISRh_RxErr);
					write_reg_high(ioaddr, CMR2, lp->addr_mode);
				} else if ((read_status & (CMR1_BufEnb << 3)) == 0) {
					net_rx(dev);
					dev->last_rx = jiffies;
					num_tx_since_rx = 0;
				} else
					break;
			} while (--boguscount > 0);
		} else if (status & ((ISR_TxErr + ISR_TxOK)<<3)) {
			if (net_debug > 6)  printk("handling Tx done..");
			/* Clear the Tx interrupt.  We should check for too many failures
			   and reinitialize the adapter. */
			write_reg(ioaddr, ISR, ISR_TxErr + ISR_TxOK);
			if (status & (ISR_TxErr<<3)) {
				lp->stats.collisions++;
				if (++lp->re_tx > 15) {
					lp->stats.tx_aborted_errors++;
					hardware_init(dev);
					break;
				}
				/* Attempt to retransmit. */
				if (net_debug > 6)  printk("attempting to ReTx");
				write_reg(ioaddr, CMR1, CMR1_ReXmit + CMR1_Xmit);
			} else {
				/* Finish up the transmit. */
				lp->stats.tx_packets++;
				lp->pac_cnt_in_tx_buf--;
				if ( lp->saved_tx_size) {
					trigger_send(ioaddr, lp->saved_tx_size);
					lp->saved_tx_size = 0;
					lp->re_tx = 0;
				} else
					lp->tx_unit_busy = 0;
				dev->tbusy = 0;
				mark_bh(NET_BH);	/* Inform upper layers. */
			}
			num_tx_since_rx++;
		} else if (num_tx_since_rx > 8
				   && jiffies > dev->last_rx + 100) {
			if (net_debug > 2)
				printk("%s: Missed packet? No Rx after %d Tx and %ld jiffies"
					   " status %02x  CMR1 %02x.\n", dev->name,
					   num_tx_since_rx, jiffies - dev->last_rx, status,
					   (read_nibble(ioaddr, CMR1) >> 3) & 15);
			lp->stats.rx_missed_errors++;
			hardware_init(dev);
			num_tx_since_rx = 0;
			break;
		} else
			break;
    }

	/* This following code fixes a rare (and very difficult to track down)
	   problem where the adapter forgets its ethernet address. */
	{
		int i;
		for (i = 0; i < 6; i++)
			write_reg_byte(ioaddr, PAR0 + i, dev->dev_addr[i]);
#ifdef TIMED_CHECKER
		del_timer(&atp_timer);
		atp_timer.expires = jiffies + TIMED_CHECKER;
		add_timer(&atp_timer);
#endif
	}

	/* Tell the adapter that it can go back to using the output line as IRQ. */
    write_reg(ioaddr, CMR2, CMR2_IRQOUT);
	/* Enable the physical interrupt line, which is sure to be low until.. */
	outb(Ctrl_SelData + Ctrl_IRQEN, ioaddr + PAR_CONTROL);
	/* .. we enable the interrupt sources. */
	write_reg(ioaddr, IMR, ISR_RxOK | ISR_TxErr | ISR_TxOK);
	write_reg_high(ioaddr, IMR, ISRh_RxErr); 			/* Hmmm, really needed? */

	if (net_debug > 5) printk("exiting interrupt.\n");

	dev->interrupt = 0;

	return;
}

#ifdef TIMED_CHECKER
/* This following code fixes a rare (and very difficult to track down)
   problem where the adapter forgets its ethernet address. */
static void atp_timed_checker(unsigned long ignored)
{
  int i;
  int ioaddr = atp_timed_dev->base_addr;

  if (!atp_timed_dev->interrupt)
	{
	  for (i = 0; i < 6; i++)
#if 0
		if (read_cmd_byte(ioaddr, PAR0 + i) != atp_timed_dev->dev_addr[i])
		  {
			struct net_local *lp = (struct net_local *)atp_timed_dev->priv;
			write_reg_byte(ioaddr, PAR0 + i, atp_timed_dev->dev_addr[i]);
			if (i == 2)
			  lp->stats.tx_errors++;
			else if (i == 3)
			  lp->stats.tx_dropped++;
			else if (i == 4)
			  lp->stats.collisions++;
			else
			  lp->stats.rx_errors++;
		  }
#else
	  write_reg_byte(ioaddr, PAR0 + i, atp_timed_dev->dev_addr[i]);
#endif
	}
  del_timer(&atp_timer);
  atp_timer.expires = jiffies + TIMED_CHECKER;
  add_timer(&atp_timer);
}
#endif

/* We have a good packet(s), get it/them out of the buffers. */
static void net_rx(struct device *dev)
{
	struct net_local *lp = (struct net_local *)dev->priv;
	int ioaddr = dev->base_addr;
#ifdef notdef
	ushort header[4];
#else
	struct rx_header rx_head;
#endif

	/* Process the received packet. */
	outb(EOC+MAR, ioaddr + PAR_DATA);
	read_block(ioaddr, 8, (unsigned char*)&rx_head, dev->if_port);
	if (net_debug > 5)
		printk(" rx_count %04x %04x %04x %04x..", rx_head.pad,
			   rx_head.rx_count, rx_head.rx_status, rx_head.cur_addr);
	if ((rx_head.rx_status & 0x77) != 0x01) {
		lp->stats.rx_errors++;
		/* Ackkk!  I don't have any documentation on what the error bits mean!
		   The best I can do is slap the device around a bit. */
		if (net_debug > 3) printk("%s: Unknown ATP Rx error %04x.\n",
								  dev->name, rx_head.rx_status);
		hardware_init(dev);
		return;
	} else {
		/* Malloc up new buffer. */
		int pkt_len = (rx_head.rx_count & 0x7ff) - 4; 		/* The "-4" is omits the FCS (CRC). */
		struct sk_buff *skb;
		
		skb = dev_alloc_skb(pkt_len);
		if (skb == NULL) {
			printk("%s: Memory squeeze, dropping packet.\n", dev->name);
			lp->stats.rx_dropped++;
			goto done;
		}
		skb->dev = dev;
		
		read_block(ioaddr, pkt_len, skb_put(skb,pkt_len), dev->if_port);

		if (net_debug > 6) {
			unsigned char *data = skb->data;
			printk(" data %02x%02x%02x %02x%02x%02x %02x%02x%02x"
				   "%02x%02x%02x %02x%02x..",
				   data[0], data[1], data[2], data[3], data[4], data[5],
				   data[6], data[7], data[8], data[9], data[10], data[11],
				   data[12], data[13]);
		}
		
		skb->protocol=eth_type_trans(skb,dev);
		netif_rx(skb);
		lp->stats.rx_packets++;
	}
 done:
	write_reg(ioaddr, CMR1, CMR1_NextPkt);
	return;
}

static void read_block(short ioaddr, int length, unsigned char *p, int data_mode)
{

	if (data_mode <= 3) { /* Mode 0 or 1 */
		outb(Ctrl_LNibRead, ioaddr + PAR_CONTROL);
		outb(length == 8  ?  RdAddr | HNib | MAR  :  RdAddr | MAR,
			 ioaddr + PAR_DATA);
		if (data_mode <= 1) { /* Mode 0 or 1 */
			do  *p++ = read_byte_mode0(ioaddr);  while (--length > 0);
		} else	/* Mode 2 or 3 */
			do  *p++ = read_byte_mode2(ioaddr);  while (--length > 0);
	} else if (data_mode <= 5)
		do      *p++ = read_byte_mode4(ioaddr);  while (--length > 0);
	else
		do      *p++ = read_byte_mode6(ioaddr);  while (--length > 0);

    outb(EOC+HNib+MAR, ioaddr + PAR_DATA);
	outb(Ctrl_SelData, ioaddr + PAR_CONTROL);
}

/* The inverse routine to net_open(). */
static int
net_close(struct device *dev)
{
	struct net_local *lp = (struct net_local *)dev->priv;
	int ioaddr = dev->base_addr;

	dev->tbusy = 1;
	dev->start = 0;

	/* Flush the Tx and disable Rx here. */
	lp->addr_mode = CMR2h_OFF;
	write_reg_high(ioaddr, CMR2, CMR2h_OFF);

	/* Free the IRQ line. */
	outb(0x00, ioaddr + PAR_CONTROL);
	free_irq(dev->irq, dev);

	/* Leave the hardware in a reset state. */
    write_reg_high(ioaddr, CMR1, CMR1h_RESET);

	return 0;
}

/* Get the current statistics.	This may be called with the card open or
   closed. */
static struct net_device_stats *net_get_stats(struct device *dev)
{
	struct net_local *lp = (struct net_local *)dev->priv;
	return &lp->stats;
}

/*
 *	Set or clear the multicast filter for this adapter.
 */
 
static void set_multicast_list(struct device *dev)
{
	struct net_local *lp = (struct net_local *)dev->priv;
	short ioaddr = dev->base_addr;
	int num_addrs=dev->mc_count;
	
	if(dev->flags&(IFF_ALLMULTI|IFF_PROMISC))
		num_addrs=1;
	/*
	 *	We must make the kernel realise we had to move
	 *	into promisc mode or we start all out war on
	 *	the cable. - AC
	 */
	if(num_addrs)
		dev->flags|=IFF_PROMISC;		
	lp->addr_mode = num_addrs ? CMR2h_PROMISC : CMR2h_Normal;
	write_reg_high(ioaddr, CMR2, lp->addr_mode);
}

/*
 * Local variables:
 *  compile-command: "gcc -D__KERNEL__ -I/usr/src/linux/net/inet -Wall -Wstrict-prototypes -O6 -m486 -c atp.c"
 *  version-control: t
 *  kept-new-versions: 5
 *  tab-width: 4
 * End:
 */