/* pcnet32.c: An AMD PCnet32 ethernet driver for linux. */
/*
 *      Copyright 1996,97 Thomas Bogendoerfer
 * 
 * 	Derived from the lance driver 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.
 *
 * 	This driver is for PCnet32 and PCnetPCI based ethercards
 */

static const char *version = "pcnet32.c:v0.23 8.2.97 tsbogend@alpha.franken.de\n";

#include <linux/config.h>
#include <linux/kernel.h>
#include <linux/sched.h>
#include <linux/string.h>
#include <linux/ptrace.h>
#include <linux/errno.h>
#include <linux/ioport.h>
#include <linux/malloc.h>
#include <linux/interrupt.h>
#include <linux/pci.h>
#include <linux/bios32.h>
#include <linux/init.h>
#include <asm/bitops.h>
#ifdef __mips__
#include <asm/bootinfo.h>
#include <asm/pgtable.h>
#include <asm/sni.h>
#endif /* __mips__ */
#include <asm/io.h>
#include <asm/dma.h>

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

static unsigned int pcnet32_portlist[] __initdata = {0x300, 0x320, 0x340, 0x360, 0};

#ifdef PCNET32_DEBUG
static int pcnet32_debug = PCNET32_DEBUG;
#else
static int pcnet32_debug = 1;
#endif

/*
 * 				Theory of Operation
 * 
 * This driver uses the same software structure as the normal lance
 * driver. So look for a verbose description in lance.c. The differences
 * to the normal lance driver is the use of the 32bit mode of PCnet32
 * and PCnetPCI chips. Because these chips are 32bit chips, there is no
 * 16MB limitation and we don't need bounce buffers.
 */
 
/*
 * History:
 * v0.01:  Initial version
 *         only tested on Alpha Noname Board
 * v0.02:  changed IRQ handling for new interrupt scheme (dev_id)
 *         tested on a ASUS SP3G
 * v0.10:  fixed an odd problem with the 79C794 in a Compaq Deskpro XL
 *         looks like the 974 doesn't like stopping and restarting in a
 *         short period of time; now we do a reinit of the lance; the
 *         bug was triggered by doing ifconfig eth0 <ip> broadcast <addr>
 *         and hangs the machine (thanks to Klaus Liedl for debugging)
 * v0.12:  by suggestion from Donald Becker: Renamed driver to pcnet32,
 *         made it standalone (no need for lance.c)
 * v0.13:  added additional PCI detecting for special PCI devices (Compaq)
 * v0.14:  stripped down additional PCI probe (thanks to David C Niemi
 *         and sveneric@xs4all.nl for testing this on their Compaq boxes)
 * v0.15:  added 79C965 (VLB) probe
 *         added interrupt sharing for PCI chips
 * v0.16:  fixed set_multicast_list on Alpha machines
 * v0.17:  removed hack from dev.c; now pcnet32 uses ethif_probe in Space.c
 * v0.19:  changed setting of autoselect bit
 * v0.20:  removed additional Compaq PCI probe; there is now a working one
 *	   in arch/i386/bios32.c
 * v0.21:  added endian conversion for ppc, from work by cort@cs.nmt.edu
 * v0.22:  added printing of status to ring dump
 * v0.23:  changed enet_statistics to net_devive_stats
 */


/*
 * Set the number of Tx and Rx buffers, using Log_2(# buffers).
 * Reasonable default values are 4 Tx buffers, and 16 Rx buffers.
 * That translates to 2 (4 == 2^^2) and 4 (16 == 2^^4).
 */
#ifndef PCNET32_LOG_TX_BUFFERS
#define PCNET32_LOG_TX_BUFFERS 4
#define PCNET32_LOG_RX_BUFFERS 4
#endif

#define TX_RING_SIZE			(1 << (PCNET32_LOG_TX_BUFFERS))
#define TX_RING_MOD_MASK		(TX_RING_SIZE - 1)
#define TX_RING_LEN_BITS		((PCNET32_LOG_TX_BUFFERS) << 12)

#define RX_RING_SIZE			(1 << (PCNET32_LOG_RX_BUFFERS))
#define RX_RING_MOD_MASK		(RX_RING_SIZE - 1)
#define RX_RING_LEN_BITS		((PCNET32_LOG_RX_BUFFERS) << 4)

#define PKT_BUF_SZ		1544

/* Offsets from base I/O address. */
#define PCNET32_DATA 0x10
#define PCNET32_ADDR 0x12
#define PCNET32_RESET 0x14
#define PCNET32_BUS_IF 0x16
#define PCNET32_TOTAL_SIZE 0x18

/* The PCNET32 Rx and Tx ring descriptors. */
struct pcnet32_rx_head {
	u32 base;
	s16 buf_length;
        s16 status;    
	u32 msg_length;
	u32 reserved;
};
	
struct pcnet32_tx_head {
	u32 base;
	s16 length;
        s16 status;
	u32 misc;
	u32 reserved;
};


/* The PCNET32 32-Bit initialization block, described in databook. */
struct pcnet32_init_block {
	u16 mode;
	u16 tlen_rlen;
	u8  phys_addr[6];
	u16 reserved;
	u32 filter[2];
	/* Receive and transmit ring base, along with extra bits. */    
	u32 rx_ring;
	u32 tx_ring;
};

struct pcnet32_private {
	/* The Tx and Rx ring entries must be aligned on 16-byte boundaries in 32bit mode. */
	struct pcnet32_rx_head   rx_ring[RX_RING_SIZE];
	struct pcnet32_tx_head   tx_ring[TX_RING_SIZE];
	struct pcnet32_init_block	init_block;
	const char *name;
	/* The saved address of a sent-in-place packet/buffer, for skfree(). */
	struct sk_buff* tx_skbuff[TX_RING_SIZE];
	unsigned long rx_buffs;			/* Address of Rx and Tx buffers. */
	int cur_rx, cur_tx;			/* The next free ring entry */
	int dirty_rx, dirty_tx;		        /* The ring entries to be free()ed. */
	struct net_device_stats stats;
	char tx_full;
	unsigned long lock;
        char shared_irq;                         /* shared irq possible */
};

int  pcnet32_probe(struct device *dev);
static int  pcnet32_probe1(struct device *dev, unsigned int ioaddr, unsigned char irq_line, int shared);
static int  pcnet32_open(struct device *dev);
static void pcnet32_init_ring(struct device *dev);
static int  pcnet32_start_xmit(struct sk_buff *skb, struct device *dev);
static int  pcnet32_rx(struct device *dev);
static void pcnet32_interrupt(int irq, void *dev_id, struct pt_regs *regs);
static int  pcnet32_close(struct device *dev);
static struct net_device_stats *pcnet32_get_stats(struct device *dev);
static void pcnet32_set_multicast_list(struct device *dev);



__initfunc(int pcnet32_probe (struct device *dev))
{
    unsigned int  ioaddr = dev ? dev->base_addr: 0;
    unsigned char irq_line = dev ? dev->irq : 0;
    int *port;
    
    if (ioaddr > 0x1ff)
      return pcnet32_probe1(dev, ioaddr, irq_line, 0);
    else if(ioaddr != 0)
      return ENXIO;
    
#if defined(CONFIG_PCI)
    if (pcibios_present()) {
	int pci_index;
	
	printk("pcnet32.c: PCI bios is present, checking for devices...\n");
	for (pci_index = 0; pci_index < 8; pci_index++) {
	    unsigned char pci_bus, pci_device_fn;
	    unsigned short pci_command;

	    if (pcibios_find_device (PCI_VENDOR_ID_AMD,
				     PCI_DEVICE_ID_AMD_LANCE, pci_index,
				     &pci_bus, &pci_device_fn) != 0)
	      break;
	    pcibios_read_config_byte(pci_bus, pci_device_fn,
				     PCI_INTERRUPT_LINE, &irq_line);
	    pcibios_read_config_dword(pci_bus, pci_device_fn,
				      PCI_BASE_ADDRESS_0, &ioaddr);
	    /* Remove I/O space marker in bit 0. */
	    ioaddr &= ~3;
	    /* PCI Spec 2.1 states that it is either the driver or PCI card's
	     * responsibility to set the PCI Master Enable Bit if needed.
	     *	(From Mark Stockton <marks@schooner.sys.hou.compaq.com>)
	     */
	    pcibios_read_config_word(pci_bus, pci_device_fn,
				     PCI_COMMAND, &pci_command);
	    
	    /* Avoid already found cards from previous pcnet32_probe() calls */
	    if (check_region(ioaddr, PCNET32_TOTAL_SIZE))
	      continue;

	    if ( ! (pci_command & PCI_COMMAND_MASTER)) {
		printk("PCI Master Bit has not been set. Setting...\n");
		pci_command |= PCI_COMMAND_MASTER|PCI_COMMAND_IO;
		pcibios_write_config_word(pci_bus, pci_device_fn,
					  PCI_COMMAND, pci_command);
	    }
#ifdef __powerpc__
	    irq_line = 15;
#endif
#ifdef CONFIG_SNI_RM200_PCI
	    if (mips_machgroup == MACH_GROUP_SNI_RM
                && mips_machtype == MACH_SNI_RM200_PCI)
	        irq_line = PCIMT_IRQ_ETHERNET;
#endif
	    
	    printk("Found PCnet/PCI at %#x, irq %d.\n",
		   ioaddr, irq_line);
	    
	    if (pcnet32_probe1(dev, ioaddr, irq_line, 1) != 0) {	/* Shouldn't happen. */
		printk(KERN_ERR "pcnet32.c: Probe of PCI card at %#x failed.\n", ioaddr);
		break;
	    }
	    return 0;
	}
    } else 
#endif  /* defined(CONFIG_PCI) */
    
    /* now look for PCnet32 VLB cards */
    for (port = pcnet32_portlist; *port; port++) {
	unsigned int ioaddr = *port;
	
	if ( check_region(ioaddr, PCNET32_TOTAL_SIZE) == 0) {
	    if (pcnet32_probe1(dev, ioaddr, 0, 0) == 0)
	      return 0;
	}
    }
    
    return ENODEV;
}


/* pcnet32_probe1 */
__initfunc(static int pcnet32_probe1(struct device *dev, unsigned int ioaddr, unsigned char irq_line, int shared))
{
    struct pcnet32_private *lp;
    int i;
    char *chipname;

    /* check if there is really a pcnet chip on that ioaddr */
    if ((inb(ioaddr + 14) != 0x57) || (inb(ioaddr + 15) != 0x57))
      return ENODEV; 
    
    inw(ioaddr+PCNET32_RESET); /* Reset the PCNET32 */

    outw(0x0000, ioaddr+PCNET32_ADDR); /* Switch to window 0 */
    if (inw(ioaddr+PCNET32_DATA) != 0x0004)
      return ENODEV;

    /* Get the version of the chip. */
    outw(88, ioaddr+PCNET32_ADDR);
    if (inw(ioaddr+PCNET32_ADDR) != 88) {
	/* should never happen */
	return ENODEV;
    } else {			/* Good, it's a newer chip. */
	int chip_version = inw(ioaddr+PCNET32_DATA);
	outw(89, ioaddr+PCNET32_ADDR);
	chip_version |= inw(ioaddr+PCNET32_DATA) << 16;
	if (pcnet32_debug > 2)
	  printk("  PCnet chip version is %#x.\n", chip_version);
	if ((chip_version & 0xfff) != 0x003)
	  return ENODEV;
	chip_version = (chip_version >> 12) & 0xffff;
	switch (chip_version) {
	 case 0x2420:
	    chipname = "PCnet/PCI 79C970";
	    break;
	 case 0x2430:
	    chipname = "PCnet32";
	    break;
	 case 0x2621:
	    chipname = "PCnet/PCI II 79C970A";
	    break;
	 default:
	    printk("pcnet32: PCnet version %#x, no PCnet32 chip.\n",chip_version);
	    return ENODEV;
	}
    }
    
    /* We should have a "dev" from Space.c or the static module table. */
    if (dev == NULL) {
	printk(KERN_ERR "pcnet32.c: Passed a NULL device.\n");
	dev = init_etherdev(0, 0);
    }

    printk("%s: %s at %#3x,", dev->name, chipname, ioaddr);

    /* There is a 16 byte station address PROM at the base address.
     The first six bytes are the station address. */
    for (i = 0; i < 6; i++)
      printk(" %2.2x", dev->dev_addr[i] = inb(ioaddr + i));

    dev->base_addr = ioaddr;
    request_region(ioaddr, PCNET32_TOTAL_SIZE, chipname);
    
    /* Make certain the data structures used by the PCnet32 are 16byte aligned and DMAble. */
    lp = (struct pcnet32_private *) (((unsigned long)kmalloc(sizeof(*lp)+15, GFP_DMA | GFP_KERNEL)+15) & ~15);
#ifdef __mips__
    /* XXX Maybe modify kmalloc() to return KSEG1 memory?  This would
     * make lots of modifications to drivers unnecessary but possibly
     * have negative impact on the performance due to drivers not being
     * aware of the CPU performance impact of GFP_DMA memory ...
     */
    flush_cache_range(current->mm, lp, sizeof(*lp)+15);
    lp = KSEG1ADDR(lp);
#endif
      
    memset(lp, 0, sizeof(*lp));
    dev->priv = lp;
    lp->name = chipname;
    lp->shared_irq = shared;
    lp->rx_buffs = (unsigned long) kmalloc(PKT_BUF_SZ*RX_RING_SIZE, GFP_DMA | GFP_KERNEL);

    lp->init_block.mode = le16_to_cpu(0x0003);	/* Disable Rx and Tx. */
    lp->init_block.tlen_rlen = le16_to_cpu(TX_RING_LEN_BITS | RX_RING_LEN_BITS); 
    for (i = 0; i < 6; i++)
      lp->init_block.phys_addr[i] = dev->dev_addr[i];
    lp->init_block.filter[0] = 0x00000000;
    lp->init_block.filter[1] = 0x00000000;
    lp->init_block.rx_ring = (u32)le32_to_cpu(virt_to_bus(lp->rx_ring));
    lp->init_block.tx_ring = (u32)le32_to_cpu(virt_to_bus(lp->tx_ring));
    
    /* switch pcnet32 to 32bit mode */
    outw(0x0014, ioaddr+PCNET32_ADDR);
    outw(0x0002, ioaddr+PCNET32_BUS_IF);

    outw(0x0001, ioaddr+PCNET32_ADDR);
    inw(ioaddr+PCNET32_ADDR);
    outw(virt_to_bus(&lp->init_block) & 0xffff, ioaddr+PCNET32_DATA);
    outw(0x0002, ioaddr+PCNET32_ADDR);
    inw(ioaddr+PCNET32_ADDR);
    outw(virt_to_bus(&lp->init_block) >> 16, ioaddr+PCNET32_DATA);
    outw(0x0000, ioaddr+PCNET32_ADDR);
    inw(ioaddr+PCNET32_ADDR);
    
    if (irq_line) {
	dev->irq = irq_line;
    }
    
    if (dev->irq >= 2)
      printk(" assigned IRQ %d.\n", dev->irq);
    else {
	/*
	 * To auto-IRQ we enable the initialization-done and DMA error
	 * interrupts. For ISA boards we get a DMA error, but VLB and PCI
	 * boards will work.
	 */
	autoirq_setup(0);
	
	/* Trigger an initialization just for the interrupt. */
	outw(0x0041, ioaddr+PCNET32_DATA);

	dev->irq = autoirq_report(1);
	if (dev->irq)
	  printk(", probed IRQ %d.\n", dev->irq);
	else {
	    printk(", failed to detect IRQ line.\n");
	    return ENODEV;
	}
    }

    outw(0x0002, ioaddr+PCNET32_ADDR);
    /* only touch autoselect bit */
    outw(inw(ioaddr+PCNET32_BUS_IF) | 0x0002, ioaddr+PCNET32_BUS_IF);


    if (pcnet32_debug > 0)
      printk(version);
    
    /* The PCNET32-specific entries in the device structure. */
    dev->open = &pcnet32_open;
    dev->hard_start_xmit = &pcnet32_start_xmit;
    dev->stop = &pcnet32_close;
    dev->get_stats = &pcnet32_get_stats;
    dev->set_multicast_list = &pcnet32_set_multicast_list;

    /* Fill in the generic fields of the device structure. */
    ether_setup(dev);
    return 0;
}


static int
pcnet32_open(struct device *dev)
{
	struct pcnet32_private *lp = (struct pcnet32_private *)dev->priv;
	unsigned int ioaddr = dev->base_addr;
	int i;

	if (dev->irq == 0 ||
		request_irq(dev->irq, &pcnet32_interrupt,
			    lp->shared_irq ? SA_SHIRQ : 0, lp->name, (void *)dev)) {
		return -EAGAIN;
	}

	/* Reset the PCNET32 */
	inw(ioaddr+PCNET32_RESET);

	/* switch pcnet32 to 32bit mode */
	outw(0x0014, ioaddr+PCNET32_ADDR);
	outw(0x0002, ioaddr+PCNET32_BUS_IF);

	/* Turn on auto-select of media (AUI, BNC). */
	outw(0x0002, ioaddr+PCNET32_ADDR);
	/* only touch autoselect bit */
	outw(inw(ioaddr+PCNET32_BUS_IF) | 0x0002, ioaddr+PCNET32_BUS_IF);

	if (pcnet32_debug > 1)
		printk("%s: pcnet32_open() irq %d tx/rx rings %#x/%#x init %#x.\n",
			   dev->name, dev->irq,
		           (u32) virt_to_bus(lp->tx_ring),
		           (u32) virt_to_bus(lp->rx_ring),
			   (u32) virt_to_bus(&lp->init_block));

	lp->init_block.mode = 0x0000;
	lp->init_block.filter[0] = 0x00000000;
	lp->init_block.filter[1] = 0x00000000;
	pcnet32_init_ring(dev);
    
	/* Re-initialize the PCNET32, and start it when done. */
	outw(0x0001, ioaddr+PCNET32_ADDR);
	outw(virt_to_bus(&lp->init_block) &0xffff, ioaddr+PCNET32_DATA);
	outw(0x0002, ioaddr+PCNET32_ADDR);
	outw(virt_to_bus(&lp->init_block) >> 16, ioaddr+PCNET32_DATA);

	outw(0x0004, ioaddr+PCNET32_ADDR);
	outw(0x0915, ioaddr+PCNET32_DATA);

	outw(0x0000, ioaddr+PCNET32_ADDR);
	outw(0x0001, ioaddr+PCNET32_DATA);

	dev->tbusy = 0;
	dev->interrupt = 0;
	dev->start = 1;
	i = 0;
	while (i++ < 100)
		if (inw(ioaddr+PCNET32_DATA) & 0x0100)
			break;
	/* 
	 * We used to clear the InitDone bit, 0x0100, here but Mark Stockton
	 * reports that doing so triggers a bug in the '974.
	 */
 	outw(0x0042, ioaddr+PCNET32_DATA);

	if (pcnet32_debug > 2)
		printk("%s: PCNET32 open after %d ticks, init block %#x csr0 %4.4x.\n",
			   dev->name, i, (u32) virt_to_bus(&lp->init_block), inw(ioaddr+PCNET32_DATA));

	return 0;					/* Always succeed */
}

/*
 * The LANCE has been halted for one reason or another (busmaster memory
 * arbitration error, Tx FIFO underflow, driver stopped it to reconfigure,
 * etc.).  Modern LANCE variants always reload their ring-buffer
 * configuration when restarted, so we must reinitialize our ring
 * context before restarting.  As part of this reinitialization,
 * find all packets still on the Tx ring and pretend that they had been
 * sent (in effect, drop the packets on the floor) - the higher-level
 * protocols will time out and retransmit.  It'd be better to shuffle
 * these skbs to a temp list and then actually re-Tx them after
 * restarting the chip, but I'm too lazy to do so right now.  dplatt@3do.com
 */

static void 
pcnet32_purge_tx_ring(struct device *dev)
{
	struct pcnet32_private *lp = (struct pcnet32_private *)dev->priv;
	int i;

	for (i = 0; i < TX_RING_SIZE; i++) {
		if (lp->tx_skbuff[i]) {
			dev_kfree_skb(lp->tx_skbuff[i],FREE_WRITE);
			lp->tx_skbuff[i] = NULL;
		}
	}
}


/* Initialize the PCNET32 Rx and Tx rings. */
static void
pcnet32_init_ring(struct device *dev)
{
	struct pcnet32_private *lp = (struct pcnet32_private *)dev->priv;
	int i;

	lp->lock = 0, lp->tx_full = 0;
	lp->cur_rx = lp->cur_tx = 0;
	lp->dirty_rx = lp->dirty_tx = 0;

	for (i = 0; i < RX_RING_SIZE; i++) {
		lp->rx_ring[i].base = (u32)le32_to_cpu(virt_to_bus((char *)lp->rx_buffs + i*PKT_BUF_SZ));
		lp->rx_ring[i].buf_length = le16_to_cpu(-PKT_BUF_SZ);
	        lp->rx_ring[i].status = le16_to_cpu(0x8000);	    
	}
	/* The Tx buffer address is filled in as needed, but we do need to clear
	   the upper ownership bit. */
	for (i = 0; i < TX_RING_SIZE; i++) {
	        lp->tx_ring[i].base = 0;
	        lp->tx_ring[i].status = 0;
	}

        lp->init_block.tlen_rlen = TX_RING_LEN_BITS | RX_RING_LEN_BITS;
	for (i = 0; i < 6; i++)
		lp->init_block.phys_addr[i] = dev->dev_addr[i];
	lp->init_block.rx_ring = (u32)le32_to_cpu(virt_to_bus(lp->rx_ring));
	lp->init_block.tx_ring = (u32)le32_to_cpu(virt_to_bus(lp->tx_ring));
}

static void
pcnet32_restart(struct device *dev, unsigned int csr0_bits, int must_reinit)
{
        int i;
	unsigned int ioaddr = dev->base_addr;
    
	pcnet32_purge_tx_ring(dev);
	pcnet32_init_ring(dev);
    
	outw(0x0000, ioaddr + PCNET32_ADDR);
        /* ReInit Ring */
        outw(0x0001, ioaddr + PCNET32_DATA);
	i = 0;
	while (i++ < 100)
		if (inw(ioaddr+PCNET32_DATA) & 0x0100)
			break;

	outw(csr0_bits, ioaddr + PCNET32_DATA);
}

static int
pcnet32_start_xmit(struct sk_buff *skb, struct device *dev)
{
	struct pcnet32_private *lp = (struct pcnet32_private *)dev->priv;
	unsigned int ioaddr = dev->base_addr;
	int entry;
	unsigned long flags;

	/* Transmitter timeout, serious problems. */
	if (dev->tbusy) {
		int tickssofar = jiffies - dev->trans_start;
		if (tickssofar < 20)
			return 1;
		outw(0, ioaddr+PCNET32_ADDR);
		printk("%s: transmit timed out, status %4.4x, resetting.\n",
			   dev->name, inw(ioaddr+PCNET32_DATA));
		outw(0x0004, ioaddr+PCNET32_DATA);
		lp->stats.tx_errors++;
#ifndef final_version
		{
			int i;
			printk(" Ring data dump: dirty_tx %d cur_tx %d%s cur_rx %d.",
				   lp->dirty_tx, lp->cur_tx, lp->tx_full ? " (full)" : "",
				   lp->cur_rx);
			for (i = 0 ; i < RX_RING_SIZE; i++)
				printk("%s %08x %04x %08x %04x", i & 1 ? "" : "\n ",
					   lp->rx_ring[i].base, -lp->rx_ring[i].buf_length,
					   lp->rx_ring[i].msg_length, (unsigned)lp->rx_ring[i].status);
			for (i = 0 ; i < TX_RING_SIZE; i++)
				printk("%s %08x %04x %08x %04x", i & 1 ? "" : "\n ",
					   lp->tx_ring[i].base, -lp->tx_ring[i].length,
					   lp->tx_ring[i].misc, (unsigned)lp->tx_ring[i].status);
			printk("\n");
		}
#endif
		pcnet32_restart(dev, 0x0042, 1);

		dev->tbusy=0;
		dev->trans_start = jiffies;

		return 0;
	}

	if (skb == NULL) {
		dev_tint(dev);
		return 0;
	}

	if (skb->len <= 0)
		return 0;

	if (pcnet32_debug > 3) {
		outw(0x0000, ioaddr+PCNET32_ADDR);
		printk("%s: pcnet32_start_xmit() called, csr0 %4.4x.\n", dev->name,
			   inw(ioaddr+PCNET32_DATA));
		outw(0x0000, ioaddr+PCNET32_DATA);
	}

	/* 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);
		return 1;
	}

	if (test_and_set_bit(0, (void*)&lp->lock) != 0) {
		if (pcnet32_debug > 0)
			printk("%s: tx queue lock!.\n", dev->name);
		/* don't clear dev->tbusy flag. */
		return 1;
	}

	/* Fill in a Tx ring entry */

	/* Mask to ring buffer boundary. */
	entry = lp->cur_tx & TX_RING_MOD_MASK;

	/* Caution: the write order is important here, set the base address
	   with the "ownership" bits last. */

	lp->tx_ring[entry].length = le16_to_cpu(-skb->len);

	lp->tx_ring[entry].misc = 0x00000000;

	lp->tx_skbuff[entry] = skb;
	lp->tx_ring[entry].base = (u32)le32_to_cpu(virt_to_bus(skb->data));
        lp->tx_ring[entry].status = le16_to_cpu(0x8300);

#ifdef __mips__
	flush_cache_range(current->mm, (void *)skb->data,
	                  (skb->len < ETH_ZLEN) ? ETH_ZLEN : skb->len);
#endif

	lp->cur_tx++;

	/* Trigger an immediate send poll. */
	outw(0x0000, ioaddr+PCNET32_ADDR);
	outw(0x0048, ioaddr+PCNET32_DATA);

	dev->trans_start = jiffies;

	save_flags(flags);
	cli();
	lp->lock = 0;
	if (lp->tx_ring[(entry+1) & TX_RING_MOD_MASK].base == 0)
		dev->tbusy=0;
	else
		lp->tx_full = 1;
	restore_flags(flags);

	return 0;
}

/* The PCNET32 interrupt handler. */
static void
pcnet32_interrupt(int irq, void *dev_id, struct pt_regs * regs)
{
	struct device *dev = (struct device *)dev_id;
	struct pcnet32_private *lp;
	unsigned int csr0, ioaddr;
	int boguscnt=10;
	int must_restart;

	if (dev == NULL) {
		printk ("pcnet32_interrupt(): irq %d for unknown device.\n", irq);
		return;
	}

	ioaddr = dev->base_addr;
	lp = (struct pcnet32_private *)dev->priv;
	if (dev->interrupt)
		printk("%s: Re-entering the interrupt handler.\n", dev->name);

	dev->interrupt = 1;

	outw(0x00, dev->base_addr + PCNET32_ADDR);
	while ((csr0 = inw(dev->base_addr + PCNET32_DATA)) & 0x8600
		   && --boguscnt >= 0) {
		/* Acknowledge all of the current interrupt sources ASAP. */
		outw(csr0 & ~0x004f, dev->base_addr + PCNET32_DATA);

		must_restart = 0;

		if (pcnet32_debug > 5)
			printk("%s: interrupt  csr0=%#2.2x new csr=%#2.2x.\n",
				   dev->name, csr0, inw(dev->base_addr + PCNET32_DATA));

		if (csr0 & 0x0400)			/* Rx interrupt */
			pcnet32_rx(dev);

		if (csr0 & 0x0200) {		/* Tx-done interrupt */
			int dirty_tx = lp->dirty_tx;

			while (dirty_tx < lp->cur_tx) {
				int entry = dirty_tx & TX_RING_MOD_MASK;
				int status = (short)le16_to_cpu(lp->tx_ring[entry].status);
			
				if (status < 0)
					break;			/* It still hasn't been Txed */

				lp->tx_ring[entry].base = 0;

				if (status & 0x4000) {
					/* There was an major error, log it. */
					int err_status = le16_to_cpu(lp->tx_ring[entry].misc);
					lp->stats.tx_errors++;
					if (err_status & 0x04000000) lp->stats.tx_aborted_errors++;
					if (err_status & 0x08000000) lp->stats.tx_carrier_errors++;
					if (err_status & 0x10000000) lp->stats.tx_window_errors++;
					if (err_status & 0x40000000) {
						/* Ackk!  On FIFO errors the Tx unit is turned off! */
						lp->stats.tx_fifo_errors++;
						/* Remove this verbosity later! */
						printk("%s: Tx FIFO error! Status %4.4x.\n",
							   dev->name, csr0);
						/* Restart the chip. */
						must_restart = 1;
					}
				} else {
					if (status & 0x1800)
						lp->stats.collisions++;
					lp->stats.tx_packets++;
				}

				/* We must free the original skb */
				if (lp->tx_skbuff[entry]) {
					dev_kfree_skb(lp->tx_skbuff[entry],FREE_WRITE);
					lp->tx_skbuff[entry] = 0;
				}
				dirty_tx++;
			}

#ifndef final_version
			if (lp->cur_tx - dirty_tx >= TX_RING_SIZE) {
				printk("out-of-sync dirty pointer, %d vs. %d, full=%d.\n",
					   dirty_tx, lp->cur_tx, lp->tx_full);
				dirty_tx += TX_RING_SIZE;
			}
#endif

			if (lp->tx_full && dev->tbusy
				&& dirty_tx > lp->cur_tx - TX_RING_SIZE + 2) {
				/* The ring is no longer full, clear tbusy. */
				lp->tx_full = 0;
				dev->tbusy = 0;
				mark_bh(NET_BH);
			}

			lp->dirty_tx = dirty_tx;
		}

		/* Log misc errors. */
		if (csr0 & 0x4000) lp->stats.tx_errors++; /* Tx babble. */
		if (csr0 & 0x1000) lp->stats.rx_errors++; /* Missed a Rx frame. */
		if (csr0 & 0x0800) {
			printk("%s: Bus master arbitration failure, status %4.4x.\n",
				   dev->name, csr0);
			/* Restart the chip. */
			must_restart = 1;
		}

		if (must_restart) {
			/* stop the chip to clear the error condition, then restart */
			outw(0x0000, dev->base_addr + PCNET32_ADDR);
			outw(0x0004, dev->base_addr + PCNET32_DATA);
			pcnet32_restart(dev, 0x0002, 0);
		}
	}

    /* Clear any other interrupt, and set interrupt enable. */
    outw(0x0000, dev->base_addr + PCNET32_ADDR);
    outw(0x7940, dev->base_addr + PCNET32_DATA);

	if (pcnet32_debug > 4)
		printk("%s: exiting interrupt, csr%d=%#4.4x.\n",
			   dev->name, inw(ioaddr + PCNET32_ADDR),
			   inw(dev->base_addr + PCNET32_DATA));

	dev->interrupt = 0;
	return;
}

static int
pcnet32_rx(struct device *dev)
{
	struct pcnet32_private *lp = (struct pcnet32_private *)dev->priv;
	int entry = lp->cur_rx & RX_RING_MOD_MASK;
	int i;
		
	/* If we own the next entry, it's a new packet. Send it up. */
	while ((short)le16_to_cpu(lp->rx_ring[entry].status) >= 0) {
		int status = (short)le16_to_cpu(lp->rx_ring[entry].status) >> 8;

		if (status != 0x03) {			/* There was an error. */
			/* There is a tricky error noted by John Murphy,
			   <murf@perftech.com> to Russ Nelson: Even with full-sized
			   buffers it's possible for a jabber packet to use two
			   buffers, with only the last correctly noting the error. */
			if (status & 0x01)	/* Only count a general error at the */
				lp->stats.rx_errors++; /* end of a packet.*/
			if (status & 0x20) lp->stats.rx_frame_errors++;
			if (status & 0x10) lp->stats.rx_over_errors++;
			if (status & 0x08) lp->stats.rx_crc_errors++;
			if (status & 0x04) lp->stats.rx_fifo_errors++;
			lp->rx_ring[entry].status &= le16_to_cpu(0x03ff);
		}
		else 
		{
			/* Malloc up new buffer, compatible with net-2e. */
			short pkt_len = (le32_to_cpu(lp->rx_ring[entry].msg_length) & 0xfff)-4;
			struct sk_buff *skb;
			
			if(pkt_len<60)
			{
				printk("%s: Runt packet!\n",dev->name);
				lp->stats.rx_errors++;
			}
			else
			{
				skb = dev_alloc_skb(pkt_len+2);
				if (skb == NULL) 
				{
					printk("%s: Memory squeeze, deferring packet.\n", dev->name);
					for (i=0; i < RX_RING_SIZE; i++)
						if ((short)le16_to_cpu(lp->rx_ring[(entry+i) & RX_RING_MOD_MASK].status) < 0)
							break;

					if (i > RX_RING_SIZE -2) 
					{
						lp->stats.rx_dropped++;
						lp->rx_ring[entry].status |= le16_to_cpu(0x8000);
						lp->cur_rx++;
					}
					break;
				}
				skb->dev = dev;
				skb_reserve(skb,2);	/* 16 byte align */
				skb_put(skb,pkt_len);	/* Make room */
				eth_copy_and_sum(skb,
					(unsigned char *)bus_to_virt(le32_to_cpu(lp->rx_ring[entry].base)),
					pkt_len,0);
				skb->protocol=eth_type_trans(skb,dev);
				netif_rx(skb);
				lp->stats.rx_packets++;
			}
		}
		/* The docs say that the buffer length isn't touched, but Andrew Boyd
		   of QNX reports that some revs of the 79C965 clear it. */
		lp->rx_ring[entry].buf_length = le16_to_cpu(-PKT_BUF_SZ);
		lp->rx_ring[entry].status |= le16_to_cpu(0x8000);
		entry = (++lp->cur_rx) & RX_RING_MOD_MASK;
	}

	/* We should check that at least two ring entries are free.	 If not,
	   we should free one and mark stats->rx_dropped++. */

	return 0;
}

static int
pcnet32_close(struct device *dev)
{
	unsigned int ioaddr = dev->base_addr;
	struct pcnet32_private *lp = (struct pcnet32_private *)dev->priv;

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

	outw(112, ioaddr+PCNET32_ADDR);
	lp->stats.rx_missed_errors = inw(ioaddr+PCNET32_DATA);

	outw(0, ioaddr+PCNET32_ADDR);

	if (pcnet32_debug > 1)
		printk("%s: Shutting down ethercard, status was %2.2x.\n",
			   dev->name, inw(ioaddr+PCNET32_DATA));

	/* We stop the PCNET32 here -- it occasionally polls
	   memory if we don't. */
	outw(0x0004, ioaddr+PCNET32_DATA);

	free_irq(dev->irq, dev);

	return 0;
}

static struct net_device_stats *
pcnet32_get_stats(struct device *dev)
{
	struct pcnet32_private *lp = (struct pcnet32_private *)dev->priv;
	unsigned int ioaddr = dev->base_addr;
	unsigned short saved_addr;
	unsigned long flags;

	save_flags(flags);
	cli();
	saved_addr = inw(ioaddr+PCNET32_ADDR);
	outw(112, ioaddr+PCNET32_ADDR);
	lp->stats.rx_missed_errors = inw(ioaddr+PCNET32_DATA);
	outw(saved_addr, ioaddr+PCNET32_ADDR);
	restore_flags(flags);

	return &lp->stats;
}

/* Set or clear the multicast filter for this adaptor.
 */

static void pcnet32_set_multicast_list(struct device *dev)
{
	unsigned int ioaddr = dev->base_addr;
	struct pcnet32_private *lp = (struct pcnet32_private *)dev->priv;    

	if (dev->flags&IFF_PROMISC) {
		/* Log any net taps. */
		printk("%s: Promiscuous mode enabled.\n", dev->name);
	        lp->init_block.mode = 0x8000;
	} else {
		int num_addrs=dev->mc_count;
		if(dev->flags&IFF_ALLMULTI)
			num_addrs=1;
		/* FIXIT: We don't use the multicast table, but rely on upper-layer filtering. */
		memset(lp->init_block.filter , (num_addrs == 0) ? 0 : -1, sizeof(lp->init_block.filter));
	        lp->init_block.mode = 0x0000;	        
	}
    
	outw(0, ioaddr+PCNET32_ADDR);
	outw(0x0004, ioaddr+PCNET32_DATA); /* Temporarily stop the lance.	 */

	pcnet32_restart(dev, 0x0042, 0); /*  Resume normal operation */

}


/*
 * Local variables:
 *  compile-command: "gcc -D__KERNEL__ -I/usr/src/linux/net/inet -Wall -Wstrict-prototypes -O6 -m486 -c pcnet32.c"
 *  c-indent-level: 4
 *  tab-width: 4
 * End:
 */