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[linux-2.6.9-moxart.git] / drivers / net / ioc3-eth.c

/*
 * This file is subject to the terms and conditions of the GNU General Public
 * License.  See the file "COPYING" in the main directory of this archive
 * for more details.
 *
 * Driver for SGI's IOC3 based Ethernet cards as found in the PCI card.
 *
 * Copyright (C) 1999, 2000, 2001, 2003 Ralf Baechle
 * Copyright (C) 1995, 1999, 2000, 2001 by Silicon Graphics, Inc.
 *
 * References:
 *  o IOC3 ASIC specification 4.51, 1996-04-18
 *  o IEEE 802.3 specification, 2000 edition
 *  o DP38840A Specification, National Semiconductor, March 1997
 *
 * To do:
 *
 *  o Handle allocation failures in ioc3_alloc_skb() more gracefully.
 *  o Handle allocation failures in ioc3_init_rings().
 *  o Use prefetching for large packets.  What is a good lower limit for
 *    prefetching?
 *  o We're probably allocating a bit too much memory.
 *  o Use hardware checksums.
 *  o Convert to using a IOC3 meta driver.
 *  o Which PHYs might possibly be attached to the IOC3 in real live,
 *    which workarounds are required for them?  Do we ever have Lucent's?
 *  o For the 2.5 branch kill the mii-tool ioctls.
 */

#define IOC3_NAME       "ioc3-eth"
#define IOC3_VERSION    "2.6.3-3"

#include <linux/config.h>
#include <linux/init.h>
#include <linux/delay.h>
#include <linux/kernel.h>
#include <linux/mm.h>
#include <linux/errno.h>
#include <linux/module.h>
#include <linux/pci.h>
#include <linux/crc32.h>
#include <linux/mii.h>
#include <linux/in.h>
#include <linux/ip.h>
#include <linux/tcp.h>
#include <linux/udp.h>

#ifdef CONFIG_SERIAL_8250
#include <linux/serial.h>
#include <asm/serial.h>
#define IOC3_BAUD (22000000 / (3*16))
#define IOC3_COM_FLAGS (ASYNC_BOOT_AUTOCONF | ASYNC_SKIP_TEST)
#endif

#include <linux/netdevice.h>
#include <linux/etherdevice.h>
#include <linux/ethtool.h>
#include <linux/skbuff.h>
#include <linux/dp83840.h>
#include <net/ip.h>

#include <asm/byteorder.h>
#include <asm/checksum.h>
#include <asm/io.h>
#include <asm/pgtable.h>
#include <asm/uaccess.h>
#include <asm/sn/types.h>
#include <asm/sn/sn0/addrs.h>
#include <asm/sn/sn0/hubni.h>
#include <asm/sn/sn0/hubio.h>
#include <asm/sn/klconfig.h>
#include <asm/sn/ioc3.h>
#include <asm/sn/sn0/ip27.h>
#include <asm/pci/bridge.h>

/*
 * 64 RX buffers.  This is tunable in the range of 16 <= x < 512.  The
 * value must be a power of two.
 */
#define RX_BUFFS 64

#define ETCSR_FD        ((17<<ETCSR_IPGR2_SHIFT) | (11<<ETCSR_IPGR1_SHIFT) | 21)
#define ETCSR_HD        ((21<<ETCSR_IPGR2_SHIFT) | (21<<ETCSR_IPGR1_SHIFT) | 21)

/* Private per NIC data of the driver.  */
struct ioc3_private {
        struct ioc3 *regs;
        unsigned long *rxr;             /* pointer to receiver ring */
        struct ioc3_etxd *txr;
        struct sk_buff *rx_skbs[512];
        struct sk_buff *tx_skbs[128];
        struct net_device_stats stats;
        int rx_ci;                      /* RX consumer index */
        int rx_pi;                      /* RX producer index */
        int tx_ci;                      /* TX consumer index */
        int tx_pi;                      /* TX producer index */
        int txqlen;
        u32 emcr, ehar_h, ehar_l;
        spinlock_t ioc3_lock;
        struct mii_if_info mii;
        struct pci_dev *pdev;

        /* Members used by autonegotiation  */
        struct timer_list ioc3_timer;
};

static inline struct net_device *priv_netdev(struct ioc3_private *dev)
{
        return (void *)dev - ((sizeof(struct net_device) + 31) & ~31);
}

static int ioc3_ioctl(struct net_device *dev, struct ifreq *rq, int cmd);
static void ioc3_set_multicast_list(struct net_device *dev);
static int ioc3_start_xmit(struct sk_buff *skb, struct net_device *dev);
static void ioc3_timeout(struct net_device *dev);
static inline unsigned int ioc3_hash(const unsigned char *addr);
static inline void ioc3_stop(struct ioc3_private *ip);
static void ioc3_init(struct net_device *dev);

static const char ioc3_str[] = "IOC3 Ethernet";
static struct ethtool_ops ioc3_ethtool_ops;

/* We use this to acquire receive skb's that we can DMA directly into. */

#define IOC3_CACHELINE  128UL

static inline unsigned long aligned_rx_skb_addr(unsigned long addr)
{
        return (~addr + 1) & (IOC3_CACHELINE - 1UL);
}

static inline struct sk_buff * ioc3_alloc_skb(unsigned long length,
        unsigned int gfp_mask)
{
        struct sk_buff *skb;

        skb = alloc_skb(length + IOC3_CACHELINE - 1, gfp_mask);
        if (likely(skb)) {
                int offset = aligned_rx_skb_addr((unsigned long) skb->data);
                if (offset)
                        skb_reserve(skb, offset);
        }

        return skb;
}

static inline unsigned long ioc3_map(void *ptr, unsigned long vdev)
{
#ifdef CONFIG_SGI_IP27
        vdev <<= 58;   /* Shift to PCI64_ATTR_VIRTUAL */

        return vdev | (0xaUL << PCI64_ATTR_TARG_SHFT) | PCI64_ATTR_PREF |
               ((unsigned long)ptr & TO_PHYS_MASK);
#else
        return virt_to_bus(ptr);
#endif
}

/* BEWARE: The IOC3 documentation documents the size of rx buffers as
   1644 while it's actually 1664.  This one was nasty to track down ...  */
#define RX_OFFSET               10
#define RX_BUF_ALLOC_SIZE       (1664 + RX_OFFSET + IOC3_CACHELINE)

/* DMA barrier to separate cached and uncached accesses.  */
#define BARRIER()                                                       \
        __asm__("sync" ::: "memory")


#define IOC3_SIZE 0x100000

/*
 * IOC3 is a big endian device
 *
 * Unorthodox but makes the users of these macros more readable - the pointer
 * to the IOC3's memory mapped registers is expected as struct ioc3 * ioc3
 * in the environment.
 */
#define ioc3_r_mcr()            be32_to_cpu(ioc3->mcr)
#define ioc3_w_mcr(v)           do { ioc3->mcr = cpu_to_be32(v); } while (0)
#define ioc3_w_gpcr_s(v)        do { ioc3->gpcr_s = cpu_to_be32(v); } while (0)
#define ioc3_r_emcr()           be32_to_cpu(ioc3->emcr)
#define ioc3_w_emcr(v)          do { ioc3->emcr = cpu_to_be32(v); } while (0)
#define ioc3_r_eisr()           be32_to_cpu(ioc3->eisr)
#define ioc3_w_eisr(v)          do { ioc3->eisr = cpu_to_be32(v); } while (0)
#define ioc3_r_eier()           be32_to_cpu(ioc3->eier)
#define ioc3_w_eier(v)          do { ioc3->eier = cpu_to_be32(v); } while (0)
#define ioc3_r_ercsr()          be32_to_cpu(ioc3->ercsr)
#define ioc3_w_ercsr(v)         do { ioc3->ercsr = cpu_to_be32(v); } while (0)
#define ioc3_r_erbr_h()         be32_to_cpu(ioc3->erbr_h)
#define ioc3_w_erbr_h(v)        do { ioc3->erbr_h = cpu_to_be32(v); } while (0)
#define ioc3_r_erbr_l()         be32_to_cpu(ioc3->erbr_l)
#define ioc3_w_erbr_l(v)        do { ioc3->erbr_l = cpu_to_be32(v); } while (0)
#define ioc3_r_erbar()          be32_to_cpu(ioc3->erbar)
#define ioc3_w_erbar(v)         do { ioc3->erbar = cpu_to_be32(v); } while (0)
#define ioc3_r_ercir()          be32_to_cpu(ioc3->ercir)
#define ioc3_w_ercir(v)         do { ioc3->ercir = cpu_to_be32(v); } while (0)
#define ioc3_r_erpir()          be32_to_cpu(ioc3->erpir)
#define ioc3_w_erpir(v)         do { ioc3->erpir = cpu_to_be32(v); } while (0)
#define ioc3_r_ertr()           be32_to_cpu(ioc3->ertr)
#define ioc3_w_ertr(v)          do { ioc3->ertr = cpu_to_be32(v); } while (0)
#define ioc3_r_etcsr()          be32_to_cpu(ioc3->etcsr)
#define ioc3_w_etcsr(v)         do { ioc3->etcsr = cpu_to_be32(v); } while (0)
#define ioc3_r_ersr()           be32_to_cpu(ioc3->ersr)
#define ioc3_w_ersr(v)          do { ioc3->ersr = cpu_to_be32(v); } while (0)
#define ioc3_r_etcdc()          be32_to_cpu(ioc3->etcdc)
#define ioc3_w_etcdc(v)         do { ioc3->etcdc = cpu_to_be32(v); } while (0)
#define ioc3_r_ebir()           be32_to_cpu(ioc3->ebir)
#define ioc3_w_ebir(v)          do { ioc3->ebir = cpu_to_be32(v); } while (0)
#define ioc3_r_etbr_h()         be32_to_cpu(ioc3->etbr_h)
#define ioc3_w_etbr_h(v)        do { ioc3->etbr_h = cpu_to_be32(v); } while (0)
#define ioc3_r_etbr_l()         be32_to_cpu(ioc3->etbr_l)
#define ioc3_w_etbr_l(v)        do { ioc3->etbr_l = cpu_to_be32(v); } while (0)
#define ioc3_r_etcir()          be32_to_cpu(ioc3->etcir)
#define ioc3_w_etcir(v)         do { ioc3->etcir = cpu_to_be32(v); } while (0)
#define ioc3_r_etpir()          be32_to_cpu(ioc3->etpir)
#define ioc3_w_etpir(v)         do { ioc3->etpir = cpu_to_be32(v); } while (0)
#define ioc3_r_emar_h()         be32_to_cpu(ioc3->emar_h)
#define ioc3_w_emar_h(v)        do { ioc3->emar_h = cpu_to_be32(v); } while (0)
#define ioc3_r_emar_l()         be32_to_cpu(ioc3->emar_l)
#define ioc3_w_emar_l(v)        do { ioc3->emar_l = cpu_to_be32(v); } while (0)
#define ioc3_r_ehar_h()         be32_to_cpu(ioc3->ehar_h)
#define ioc3_w_ehar_h(v)        do { ioc3->ehar_h = cpu_to_be32(v); } while (0)
#define ioc3_r_ehar_l()         be32_to_cpu(ioc3->ehar_l)
#define ioc3_w_ehar_l(v)        do { ioc3->ehar_l = cpu_to_be32(v); } while (0)
#define ioc3_r_micr()           be32_to_cpu(ioc3->micr)
#define ioc3_w_micr(v)          do { ioc3->micr = cpu_to_be32(v); } while (0)
#define ioc3_r_midr_r()         be32_to_cpu(ioc3->midr_r)
#define ioc3_w_midr_r(v)        do { ioc3->midr_r = cpu_to_be32(v); } while (0)
#define ioc3_r_midr_w()         be32_to_cpu(ioc3->midr_w)
#define ioc3_w_midr_w(v)        do { ioc3->midr_w = cpu_to_be32(v); } while (0)

static inline u32 mcr_pack(u32 pulse, u32 sample)
{
        return (pulse << 10) | (sample << 2);
}

static int nic_wait(struct ioc3 *ioc3)
{
        u32 mcr;

        do {
                mcr = ioc3_r_mcr();
        } while (!(mcr & 2));

        return mcr & 1;
}

static int nic_reset(struct ioc3 *ioc3)
{
        int presence;

        ioc3_w_mcr(mcr_pack(500, 65));
        presence = nic_wait(ioc3);

        ioc3_w_mcr(mcr_pack(0, 500));
        nic_wait(ioc3);

        return presence;
}

static inline int nic_read_bit(struct ioc3 *ioc3)
{
        int result;

        ioc3_w_mcr(mcr_pack(6, 13));
        result = nic_wait(ioc3);
        ioc3_w_mcr(mcr_pack(0, 100));
        nic_wait(ioc3);

        return result;
}

static inline void nic_write_bit(struct ioc3 *ioc3, int bit)
{
        if (bit)
                ioc3_w_mcr(mcr_pack(6, 110));
        else
                ioc3_w_mcr(mcr_pack(80, 30));

        nic_wait(ioc3);
}

/*
 * Read a byte from an iButton device
 */
static u32 nic_read_byte(struct ioc3 *ioc3)
{
        u32 result = 0;
        int i;

        for (i = 0; i < 8; i++)
                result = (result >> 1) | (nic_read_bit(ioc3) << 7);

        return result;
}

/*
 * Write a byte to an iButton device
 */
static void nic_write_byte(struct ioc3 *ioc3, int byte)
{
        int i, bit;

        for (i = 8; i; i--) {
                bit = byte & 1;
                byte >>= 1;

                nic_write_bit(ioc3, bit);
        }
}

static u64 nic_find(struct ioc3 *ioc3, int *last)
{
        int a, b, index, disc;
        u64 address = 0;

        nic_reset(ioc3);
        /* Search ROM.  */
        nic_write_byte(ioc3, 0xf0);

        /* Algorithm from ``Book of iButton Standards''.  */
        for (index = 0, disc = 0; index < 64; index++) {
                a = nic_read_bit(ioc3);
                b = nic_read_bit(ioc3);

                if (a && b) {
                        printk("NIC search failed (not fatal).\n");
                        *last = 0;
                        return 0;
                }

                if (!a && !b) {
                        if (index == *last) {
                                address |= 1UL << index;
                        } else if (index > *last) {
                                address &= ~(1UL << index);
                                disc = index;
                        } else if ((address & (1UL << index)) == 0)
                                disc = index;
                        nic_write_bit(ioc3, address & (1UL << index));
                        continue;
                } else {
                        if (a)
                                address |= 1UL << index;
                        else
                                address &= ~(1UL << index);
                        nic_write_bit(ioc3, a);
                        continue;
                }
        }

        *last = disc;

        return address;
}

static int nic_init(struct ioc3 *ioc3)
{
        const char *type;
        u8 crc;
        u8 serial[6];
        int save = 0, i;

        type = "unknown";

        while (1) {
                u64 reg;
                reg = nic_find(ioc3, &save);

                switch (reg & 0xff) {
                case 0x91:
                        type = "DS1981U";
                        break;
                default:
                        if (save == 0) {
                                /* Let the caller try again.  */
                                return -1;
                        }
                        continue;
                }

                nic_reset(ioc3);

                /* Match ROM.  */
                nic_write_byte(ioc3, 0x55);
                for (i = 0; i < 8; i++)
                        nic_write_byte(ioc3, (reg >> (i << 3)) & 0xff);

                reg >>= 8; /* Shift out type.  */
                for (i = 0; i < 6; i++) {
                        serial[i] = reg & 0xff;
                        reg >>= 8;
                }
                crc = reg & 0xff;
                break;
        }

        printk("Found %s NIC", type);
        if (type != "unknown") {
                printk (" registration number %02x:%02x:%02x:%02x:%02x:%02x,"
                        " CRC %02x", serial[0], serial[1], serial[2],
                        serial[3], serial[4], serial[5], crc);
        }
        printk(".\n");

        return 0;
}

/*
 * Read the NIC (Number-In-a-Can) device used to store the MAC address on
 * SN0 / SN00 nodeboards and PCI cards.
 */
static void ioc3_get_eaddr_nic(struct ioc3_private *ip)
{
        struct ioc3 *ioc3 = ip->regs;
        u8 nic[14];
        int tries = 2; /* There may be some problem with the battery?  */
        int i;

        ioc3_w_gpcr_s(1 << 21);

        while (tries--) {
                if (!nic_init(ioc3))
                        break;
                udelay(500);
        }

        if (tries < 0) {
                printk("Failed to read MAC address\n");
                return;
        }

        /* Read Memory.  */
        nic_write_byte(ioc3, 0xf0);
        nic_write_byte(ioc3, 0x00);
        nic_write_byte(ioc3, 0x00);

        for (i = 13; i >= 0; i--)
                nic[i] = nic_read_byte(ioc3);

        for (i = 2; i < 8; i++)
                priv_netdev(ip)->dev_addr[i - 2] = nic[i];
}

/*
 * Ok, this is hosed by design.  It's necessary to know what machine the
 * NIC is in in order to know how to read the NIC address.  We also have
 * to know if it's a PCI card or a NIC in on the node board ...
 */
static void ioc3_get_eaddr(struct ioc3_private *ip)
{
        int i;


        ioc3_get_eaddr_nic(ip);

        printk("Ethernet address is ");
        for (i = 0; i < 6; i++) {
                printk("%02x", priv_netdev(ip)->dev_addr[i]);
                if (i < 5)
                        printk(":");
        }
        printk(".\n");
}


/*
 * Caller must hold the ioc3_lock ever for MII readers.  This is also
 * used to protect the transmitter side but it's low contention.
 */
static int ioc3_mdio_read(struct net_device *dev, int phy, int reg)
{
        struct ioc3_private *ip = netdev_priv(dev);
        struct ioc3 *ioc3 = ip->regs;

        while (ioc3_r_micr() & MICR_BUSY);
        ioc3_w_micr((phy << MICR_PHYADDR_SHIFT) | reg | MICR_READTRIG);
        while (ioc3_r_micr() & MICR_BUSY);

        return ioc3_r_micr() & MIDR_DATA_MASK;
}

static void ioc3_mdio_write(struct net_device *dev, int phy, int reg, int data)
{
        struct ioc3_private *ip = netdev_priv(dev);
        struct ioc3 *ioc3 = ip->regs;

        while (ioc3_r_micr() & MICR_BUSY);
        ioc3_w_midr_w(data);
        ioc3_w_micr((phy << MICR_PHYADDR_SHIFT) | reg);
        while (ioc3_r_micr() & MICR_BUSY);
}

static int ioc3_mii_init(struct ioc3_private *ip);

static struct net_device_stats *ioc3_get_stats(struct net_device *dev)
{
        struct ioc3_private *ip = netdev_priv(dev);
        struct ioc3 *ioc3 = ip->regs;

        ip->stats.collisions += (ioc3_r_etcdc() & ETCDC_COLLCNT_MASK);
        return &ip->stats;
}

#ifdef CONFIG_SGI_IOC3_ETH_HW_RX_CSUM

static void ioc3_tcpudp_checksum(struct sk_buff *skb, uint32_t hwsum, int len)
{
        struct ethhdr *eh = eth_hdr(skb);
        uint32_t csum, ehsum;
        unsigned int proto;
        struct iphdr *ih;
        uint16_t *ew;
        unsigned char *cp;

        /*
         * Did hardware handle the checksum at all?  The cases we can handle
         * are:
         *
         * - TCP and UDP checksums of IPv4 only.
         * - IPv6 would be doable but we keep that for later ...
         * - Only unfragmented packets.  Did somebody already tell you
         *   fragmentation is evil?
         * - don't care about packet size.  Worst case when processing a
         *   malformed packet we'll try to access the packet at ip header +
         *   64 bytes which is still inside the skb.  Even in the unlikely
         *   case where the checksum is right the higher layers will still
         *   drop the packet as appropriate.
         */
        if (eh->h_proto != ntohs(ETH_P_IP))
                return;

        ih = (struct iphdr *) ((char *)eh + ETH_HLEN);
        if (ih->frag_off & htons(IP_MF | IP_OFFSET))
                return;

        proto = ih->protocol;
        if (proto != IPPROTO_TCP && proto != IPPROTO_UDP)
                return;

        /* Same as tx - compute csum of pseudo header  */
        csum = hwsum +
               (ih->tot_len - (ih->ihl << 2)) +
               htons((uint16_t)ih->protocol) +
               (ih->saddr >> 16) + (ih->saddr & 0xffff) +
               (ih->daddr >> 16) + (ih->daddr & 0xffff);

        /* Sum up ethernet dest addr, src addr and protocol  */
        ew = (uint16_t *) eh;
        ehsum = ew[0] + ew[1] + ew[2] + ew[3] + ew[4] + ew[5] + ew[6];

        ehsum = (ehsum & 0xffff) + (ehsum >> 16);
        ehsum = (ehsum & 0xffff) + (ehsum >> 16);

        csum += 0xffff ^ ehsum;

        /* In the next step we also subtract the 1's complement
           checksum of the trailing ethernet CRC.  */
        cp = (char *)eh + len;  /* points at trailing CRC */
        if (len & 1) {
                csum += 0xffff ^ (uint16_t) ((cp[1] << 8) | cp[0]);
                csum += 0xffff ^ (uint16_t) ((cp[3] << 8) | cp[2]);
        } else {
                csum += 0xffff ^ (uint16_t) ((cp[0] << 8) | cp[1]);
                csum += 0xffff ^ (uint16_t) ((cp[2] << 8) | cp[3]);
        }

        csum = (csum & 0xffff) + (csum >> 16);
        csum = (csum & 0xffff) + (csum >> 16);

        if (csum == 0xffff)
                skb->ip_summed = CHECKSUM_UNNECESSARY;
}
#endif /* CONFIG_SGI_IOC3_ETH_HW_RX_CSUM */

static inline void ioc3_rx(struct ioc3_private *ip)
{
        struct sk_buff *skb, *new_skb;
        struct ioc3 *ioc3 = ip->regs;
        int rx_entry, n_entry, len;
        struct ioc3_erxbuf *rxb;
        unsigned long *rxr;
        u32 w0, err;

        rxr = (unsigned long *) ip->rxr;                /* Ring base */
        rx_entry = ip->rx_ci;                           /* RX consume index */
        n_entry = ip->rx_pi;

        skb = ip->rx_skbs[rx_entry];
        rxb = (struct ioc3_erxbuf *) (skb->data - RX_OFFSET);
        w0 = be32_to_cpu(rxb->w0);

        while (w0 & ERXBUF_V) {
                err = be32_to_cpu(rxb->err);            /* It's valid ...  */
                if (err & ERXBUF_GOODPKT) {
                        len = ((w0 >> ERXBUF_BYTECNT_SHIFT) & 0x7ff) - 4;
                        skb_trim(skb, len);
                        skb->protocol = eth_type_trans(skb, priv_netdev(ip));

                        new_skb = ioc3_alloc_skb(RX_BUF_ALLOC_SIZE, GFP_ATOMIC);
                        if (!new_skb) {
                                /* Ouch, drop packet and just recycle packet
                                   to keep the ring filled.  */
                                ip->stats.rx_dropped++;
                                new_skb = skb;
                                goto next;
                        }

#ifdef CONFIG_SGI_IOC3_ETH_HW_RX_CSUM
                        ioc3_tcpudp_checksum(skb, w0 & ERXBUF_IPCKSUM_MASK,len);
#endif

                        netif_rx(skb);

                        ip->rx_skbs[rx_entry] = NULL;   /* Poison  */

                        new_skb->dev = priv_netdev(ip);

                        /* Because we reserve afterwards. */
                        skb_put(new_skb, (1664 + RX_OFFSET));
                        rxb = (struct ioc3_erxbuf *) new_skb->data;
                        skb_reserve(new_skb, RX_OFFSET);

                        priv_netdev(ip)->last_rx = jiffies;
                        ip->stats.rx_packets++;         /* Statistics */
                        ip->stats.rx_bytes += len;
                } else {
                        /* The frame is invalid and the skb never
                           reached the network layer so we can just
                           recycle it.  */
                        new_skb = skb;
                        ip->stats.rx_errors++;
                }
                if (err & ERXBUF_CRCERR)        /* Statistics */
                        ip->stats.rx_crc_errors++;
                if (err & ERXBUF_FRAMERR)
                        ip->stats.rx_frame_errors++;
next:
                ip->rx_skbs[n_entry] = new_skb;
                rxr[n_entry] = cpu_to_be64(ioc3_map(rxb, 1));
                rxb->w0 = 0;                            /* Clear valid flag */
                n_entry = (n_entry + 1) & 511;          /* Update erpir */

                /* Now go on to the next ring entry.  */
                rx_entry = (rx_entry + 1) & 511;
                skb = ip->rx_skbs[rx_entry];
                rxb = (struct ioc3_erxbuf *) (skb->data - RX_OFFSET);
                w0 = be32_to_cpu(rxb->w0);
        }
        ioc3_w_erpir((n_entry << 3) | ERPIR_ARM);
        ip->rx_pi = n_entry;
        ip->rx_ci = rx_entry;
}

static inline void ioc3_tx(struct ioc3_private *ip)
{
        unsigned long packets, bytes;
        struct ioc3 *ioc3 = ip->regs;
        int tx_entry, o_entry;
        struct sk_buff *skb;
        u32 etcir;

        spin_lock(&ip->ioc3_lock);
        etcir = ioc3_r_etcir();

        tx_entry = (etcir >> 7) & 127;
        o_entry = ip->tx_ci;
        packets = 0;
        bytes = 0;

        while (o_entry != tx_entry) {
                packets++;
                skb = ip->tx_skbs[o_entry];
                bytes += skb->len;
                dev_kfree_skb_irq(skb);
                ip->tx_skbs[o_entry] = NULL;

                o_entry = (o_entry + 1) & 127;          /* Next */

                etcir = ioc3_r_etcir();                 /* More pkts sent?  */
                tx_entry = (etcir >> 7) & 127;
        }

        ip->stats.tx_packets += packets;
        ip->stats.tx_bytes += bytes;
        ip->txqlen -= packets;

        if (ip->txqlen < 128)
                netif_wake_queue(priv_netdev(ip));

        ip->tx_ci = o_entry;
        spin_unlock(&ip->ioc3_lock);
}

/*
 * Deal with fatal IOC3 errors.  This condition might be caused by a hard or
 * software problems, so we should try to recover
 * more gracefully if this ever happens.  In theory we might be flooded
 * with such error interrupts if something really goes wrong, so we might
 * also consider to take the interface down.
 */
static void ioc3_error(struct ioc3_private *ip, u32 eisr)
{
        struct net_device *dev = priv_netdev(ip);
        unsigned char *iface = dev->name;

        spin_lock(&ip->ioc3_lock);

        if (eisr & EISR_RXOFLO)
                printk(KERN_ERR "%s: RX overflow.\n", iface);
        if (eisr & EISR_RXBUFOFLO)
                printk(KERN_ERR "%s: RX buffer overflow.\n", iface);
        if (eisr & EISR_RXMEMERR)
                printk(KERN_ERR "%s: RX PCI error.\n", iface);
        if (eisr & EISR_RXPARERR)
                printk(KERN_ERR "%s: RX SSRAM parity error.\n", iface);
        if (eisr & EISR_TXBUFUFLO)
                printk(KERN_ERR "%s: TX buffer underflow.\n", iface);
        if (eisr & EISR_TXMEMERR)
                printk(KERN_ERR "%s: TX PCI error.\n", iface);

        ioc3_stop(ip);
        ioc3_init(dev);
        ioc3_mii_init(ip);

        netif_wake_queue(dev);

        spin_unlock(&ip->ioc3_lock);
}

/* The interrupt handler does all of the Rx thread work and cleans up
   after the Tx thread.  */
static irqreturn_t ioc3_interrupt(int irq, void *_dev, struct pt_regs *regs)
{
        struct net_device *dev = (struct net_device *)_dev;
        struct ioc3_private *ip = netdev_priv(dev);
        struct ioc3 *ioc3 = ip->regs;
        const u32 enabled = EISR_RXTIMERINT | EISR_RXOFLO | EISR_RXBUFOFLO |
                            EISR_RXMEMERR | EISR_RXPARERR | EISR_TXBUFUFLO |
                            EISR_TXEXPLICIT | EISR_TXMEMERR;
        u32 eisr;

        eisr = ioc3_r_eisr() & enabled;

        ioc3_w_eisr(eisr);
        (void) ioc3_r_eisr();                           /* Flush */

        if (eisr & (EISR_RXOFLO | EISR_RXBUFOFLO | EISR_RXMEMERR |
                    EISR_RXPARERR | EISR_TXBUFUFLO | EISR_TXMEMERR))
                ioc3_error(ip, eisr);
        if (eisr & EISR_RXTIMERINT)
                ioc3_rx(ip);
        if (eisr & EISR_TXEXPLICIT)
                ioc3_tx(ip);

        return IRQ_HANDLED;
}

static inline void ioc3_setup_duplex(struct ioc3_private *ip)
{
        struct ioc3 *ioc3 = ip->regs;

        if (ip->mii.full_duplex) {
                ioc3_w_etcsr(ETCSR_FD);
                ip->emcr |= EMCR_DUPLEX;
        } else {
                ioc3_w_etcsr(ETCSR_HD);
                ip->emcr &= ~EMCR_DUPLEX;
        }
        ioc3_w_emcr(ip->emcr);
}

static void ioc3_timer(unsigned long data)
{
        struct ioc3_private *ip = (struct ioc3_private *) data;

        /* Print the link status if it has changed */
        mii_check_media(&ip->mii, 1, 0);
        ioc3_setup_duplex(ip);

        ip->ioc3_timer.expires = jiffies + ((12 * HZ)/10); /* 1.2s */
        add_timer(&ip->ioc3_timer);
}

/*
 * Try to find a PHY.  There is no apparent relation between the MII addresses
 * in the SGI documentation and what we find in reality, so we simply probe
 * for the PHY.  It seems IOC3 PHYs usually live on address 31.  One of my
 * onboard IOC3s has the special oddity that probing doesn't seem to find it
 * yet the interface seems to work fine, so if probing fails we for now will
 * simply default to PHY 31 instead of bailing out.
 */
static int ioc3_mii_init(struct ioc3_private *ip)
{
        struct net_device *dev = priv_netdev(ip);
        int i, found = 0, res = 0;
        int ioc3_phy_workaround = 1;
        u16 word;

        for (i = 0; i < 32; i++) {
                word = ioc3_mdio_read(dev, i, MII_PHYSID1);

                if (word != 0xffff && word != 0x0000) {
                        found = 1;
                        break;                  /* Found a PHY          */
                }
        }

        if (!found) {
                if (ioc3_phy_workaround)
                        i = 31;
                else {
                        ip->mii.phy_id = -1;
                        res = -ENODEV;
                        goto out;
                }
        }

        ip->mii.phy_id = i;
        ip->ioc3_timer.expires = jiffies + (12 * HZ)/10;  /* 1.2 sec. */
        ip->ioc3_timer.data = (unsigned long) ip;
        ip->ioc3_timer.function = &ioc3_timer;
        add_timer(&ip->ioc3_timer);

out:
        return res;
}

static inline void ioc3_clean_rx_ring(struct ioc3_private *ip)
{
        struct sk_buff *skb;
        int i;

        for (i = ip->rx_ci; i & 15; i++) {
                ip->rx_skbs[ip->rx_pi] = ip->rx_skbs[ip->rx_ci];
                ip->rxr[ip->rx_pi++] = ip->rxr[ip->rx_ci++];
        }
        ip->rx_pi &= 511;
        ip->rx_ci &= 511;

        for (i = ip->rx_ci; i != ip->rx_pi; i = (i+1) & 511) {
                struct ioc3_erxbuf *rxb;
                skb = ip->rx_skbs[i];
                rxb = (struct ioc3_erxbuf *) (skb->data - RX_OFFSET);
                rxb->w0 = 0;
        }
}

static inline void ioc3_clean_tx_ring(struct ioc3_private *ip)
{
        struct sk_buff *skb;
        int i;

        for (i=0; i < 128; i++) {
                skb = ip->tx_skbs[i];
                if (skb) {
                        ip->tx_skbs[i] = NULL;
                        dev_kfree_skb_any(skb);
                }
                ip->txr[i].cmd = 0;
        }
        ip->tx_pi = 0;
        ip->tx_ci = 0;
}

static void ioc3_free_rings(struct ioc3_private *ip)
{
        struct sk_buff *skb;
        int rx_entry, n_entry;

        if (ip->txr) {
                ioc3_clean_tx_ring(ip);
                free_pages((unsigned long)ip->txr, 2);
                ip->txr = NULL;
        }

        if (ip->rxr) {
                n_entry = ip->rx_ci;
                rx_entry = ip->rx_pi;

                while (n_entry != rx_entry) {
                        skb = ip->rx_skbs[n_entry];
                        if (skb)
                                dev_kfree_skb_any(skb);

                        n_entry = (n_entry + 1) & 511;
                }
                free_page((unsigned long)ip->rxr);
                ip->rxr = NULL;
        }
}

static void ioc3_alloc_rings(struct net_device *dev)
{
        struct ioc3_private *ip = netdev_priv(dev);
        struct ioc3_erxbuf *rxb;
        unsigned long *rxr;
        int i;

        if (ip->rxr == NULL) {
                /* Allocate and initialize rx ring.  4kb = 512 entries  */
                ip->rxr = (unsigned long *) get_zeroed_page(GFP_ATOMIC);
                rxr = (unsigned long *) ip->rxr;
                if (!rxr)
                        printk("ioc3_alloc_rings(): get_zeroed_page() failed!\n");

                /* Now the rx buffers.  The RX ring may be larger but
                   we only allocate 16 buffers for now.  Need to tune
                   this for performance and memory later.  */
                for (i = 0; i < RX_BUFFS; i++) {
                        struct sk_buff *skb;

                        skb = ioc3_alloc_skb(RX_BUF_ALLOC_SIZE, GFP_ATOMIC);
                        if (!skb) {
                                show_free_areas();
                                continue;
                        }

                        ip->rx_skbs[i] = skb;
                        skb->dev = dev;

                        /* Because we reserve afterwards. */
                        skb_put(skb, (1664 + RX_OFFSET));
                        rxb = (struct ioc3_erxbuf *) skb->data;
                        rxr[i] = cpu_to_be64(ioc3_map(rxb, 1));
                        skb_reserve(skb, RX_OFFSET);
                }
                ip->rx_ci = 0;
                ip->rx_pi = RX_BUFFS;
        }

        if (ip->txr == NULL) {
                /* Allocate and initialize tx rings.  16kb = 128 bufs.  */
                ip->txr = (struct ioc3_etxd *)__get_free_pages(GFP_KERNEL, 2);
                if (!ip->txr)
                        printk("ioc3_alloc_rings(): __get_free_pages() failed!\n");
                ip->tx_pi = 0;
                ip->tx_ci = 0;
        }
}

static void ioc3_init_rings(struct net_device *dev)
{
        struct ioc3_private *ip = netdev_priv(dev);
        struct ioc3 *ioc3 = ip->regs;
        unsigned long ring;

        ioc3_free_rings(ip);
        ioc3_alloc_rings(dev);

        ioc3_clean_rx_ring(ip);
        ioc3_clean_tx_ring(ip);

        /* Now the rx ring base, consume & produce registers.  */
        ring = ioc3_map(ip->rxr, 0);
        ioc3_w_erbr_h(ring >> 32);
        ioc3_w_erbr_l(ring & 0xffffffff);
        ioc3_w_ercir(ip->rx_ci << 3);
        ioc3_w_erpir((ip->rx_pi << 3) | ERPIR_ARM);

        ring = ioc3_map(ip->txr, 0);

        ip->txqlen = 0;                                 /* nothing queued  */

        /* Now the tx ring base, consume & produce registers.  */
        ioc3_w_etbr_h(ring >> 32);
        ioc3_w_etbr_l(ring & 0xffffffff);
        ioc3_w_etpir(ip->tx_pi << 7);
        ioc3_w_etcir(ip->tx_ci << 7);
        (void) ioc3_r_etcir();                          /* Flush */
}

static inline void ioc3_ssram_disc(struct ioc3_private *ip)
{
        struct ioc3 *ioc3 = ip->regs;
        volatile u32 *ssram0 = &ioc3->ssram[0x0000];
        volatile u32 *ssram1 = &ioc3->ssram[0x4000];
        unsigned int pattern = 0x5555;

        /* Assume the larger size SSRAM and enable parity checking */
        ioc3_w_emcr(ioc3_r_emcr() | (EMCR_BUFSIZ | EMCR_RAMPAR));

        *ssram0 = pattern;
        *ssram1 = ~pattern & IOC3_SSRAM_DM;

        if ((*ssram0 & IOC3_SSRAM_DM) != pattern ||
            (*ssram1 & IOC3_SSRAM_DM) != (~pattern & IOC3_SSRAM_DM)) {
                /* set ssram size to 64 KB */
                ip->emcr = EMCR_RAMPAR;
                ioc3_w_emcr(ioc3_r_emcr() & ~EMCR_BUFSIZ);
        } else
                ip->emcr = EMCR_BUFSIZ | EMCR_RAMPAR;
}

static void ioc3_init(struct net_device *dev)
{
        struct ioc3_private *ip = netdev_priv(dev);
        struct ioc3 *ioc3 = ip->regs;

        del_timer(&ip->ioc3_timer);             /* Kill if running      */

        ioc3_w_emcr(EMCR_RST);                  /* Reset                */
        (void) ioc3_r_emcr();                   /* Flush WB             */
        udelay(4);                              /* Give it time ...     */
        ioc3_w_emcr(0);
        (void) ioc3_r_emcr();

        /* Misc registers  */
#ifdef CONFIG_SGI_IP27
        ioc3_w_erbar(PCI64_ATTR_BAR >> 32);     /* Barrier on last store */
#else
        ioc3_w_erbar(0);                        /* Let PCI API get it right */
#endif
        (void) ioc3_r_etcdc();                  /* Clear on read */
        ioc3_w_ercsr(15);                       /* RX low watermark  */
        ioc3_w_ertr(0);                         /* Interrupt immediately */
        ioc3_w_emar_h((dev->dev_addr[5] <<  8) | dev->dev_addr[4]);
        ioc3_w_emar_l((dev->dev_addr[3] << 24) | (dev->dev_addr[2] << 16) |
                      (dev->dev_addr[1] <<  8) | dev->dev_addr[0]);
        ioc3_w_ehar_h(ip->ehar_h);
        ioc3_w_ehar_l(ip->ehar_l);
        ioc3_w_ersr(42);                        /* XXX should be random */

        ioc3_init_rings(dev);

        ip->emcr |= ((RX_OFFSET / 2) << EMCR_RXOFF_SHIFT) | EMCR_TXDMAEN |
                     EMCR_TXEN | EMCR_RXDMAEN | EMCR_RXEN | EMCR_PADEN;
        ioc3_w_emcr(ip->emcr);
        ioc3_w_eier(EISR_RXTIMERINT | EISR_RXOFLO | EISR_RXBUFOFLO |
                    EISR_RXMEMERR | EISR_RXPARERR | EISR_TXBUFUFLO |
                    EISR_TXEXPLICIT | EISR_TXMEMERR);
        (void) ioc3_r_eier();
}

static inline void ioc3_stop(struct ioc3_private *ip)
{
        struct ioc3 *ioc3 = ip->regs;

        ioc3_w_emcr(0);                         /* Shutup */
        ioc3_w_eier(0);                         /* Disable interrupts */
        (void) ioc3_r_eier();                   /* Flush */
}

static int ioc3_open(struct net_device *dev)
{
        struct ioc3_private *ip = netdev_priv(dev);

        if (request_irq(dev->irq, ioc3_interrupt, SA_SHIRQ, ioc3_str, dev)) {
                printk(KERN_ERR "%s: Can't get irq %d\n", dev->name, dev->irq);

                return -EAGAIN;
        }

        ip->ehar_h = 0;
        ip->ehar_l = 0;
        ioc3_init(dev);

        netif_start_queue(dev);
        return 0;
}

static int ioc3_close(struct net_device *dev)
{
        struct ioc3_private *ip = netdev_priv(dev);

        del_timer(&ip->ioc3_timer);

        netif_stop_queue(dev);

        ioc3_stop(ip);
        free_irq(dev->irq, dev);

        ioc3_free_rings(ip);
        return 0;
}

/*
 * MENET cards have four IOC3 chips, which are attached to two sets of
 * PCI slot resources each: the primary connections are on slots
 * 0..3 and the secondaries are on 4..7
 *
 * All four ethernets are brought out to connectors; six serial ports
 * (a pair from each of the first three IOC3s) are brought out to
 * MiniDINs; all other subdevices are left swinging in the wind, leave
 * them disabled.
 */
static inline int ioc3_is_menet(struct pci_dev *pdev)
{
        struct pci_dev *dev;

        return pdev->bus->parent == NULL
               && (dev = pci_find_slot(pdev->bus->number, PCI_DEVFN(0, 0)))
               && dev->vendor == PCI_VENDOR_ID_SGI
               && dev->device == PCI_DEVICE_ID_SGI_IOC3
               && (dev = pci_find_slot(pdev->bus->number, PCI_DEVFN(1, 0)))
               && dev->vendor == PCI_VENDOR_ID_SGI
               && dev->device == PCI_DEVICE_ID_SGI_IOC3
               && (dev = pci_find_slot(pdev->bus->number, PCI_DEVFN(2, 0)))
               && dev->vendor == PCI_VENDOR_ID_SGI
               && dev->device == PCI_DEVICE_ID_SGI_IOC3;
}

/*
 * Note about serial ports and consoles:
 * For console output, everyone uses the IOC3 UARTA (offset 0x178)
 * connected to the master node (look in ip27_setup_console() and
 * ip27prom_console_write()).
 *
 * For serial (/dev/ttyS0 etc), we can not have hardcoded serial port
 * addresses on a partitioned machine. Since we currently use the ioc3
 * serial ports, we use dynamic serial port discovery that the serial.c
 * driver uses for pci/pnp ports (there is an entry for the SGI ioc3
 * boards in pci_boards[]). Unfortunately, UARTA's pio address is greater
 * than UARTB's, although UARTA on o200s has traditionally been known as
 * port 0. So, we just use one serial port from each ioc3 (since the
 * serial driver adds addresses to get to higher ports).
 *
 * The first one to do a register_console becomes the preferred console
 * (if there is no kernel command line console= directive). /dev/console
 * (ie 5, 1) is then "aliased" into the device number returned by the
 * "device" routine referred to in this console structure
 * (ip27prom_console_dev).
 *
 * Also look in ip27-pci.c:pci_fixuop_ioc3() for some comments on working
 * around ioc3 oddities in this respect.
 *
 * The IOC3 serials use a 22MHz clock rate with an additional divider by 3.
 * (IOC3_BAUD = (22000000 / (3*16)))
 */

static inline void ioc3_serial_probe(struct pci_dev *pdev,
                                struct ioc3 *ioc3)
{
        struct serial_struct req;

        /*
         * We need to recognice and treat the fourth MENET serial as it
         * does not have an SuperIO chip attached to it, therefore attempting
         * to access it will result in bus errors.  We call something an
         * MENET if PCI slot 0, 1, 2 and 3 of a master PCI bus all have an IOC3
         * in it.  This is paranoid but we want to avoid blowing up on a
         * showhorn PCI box that happens to have 4 IOC3 cards in it so it's
         * not paranoid enough ...
         */
        if (ioc3_is_menet(pdev) && PCI_SLOT(pdev->devfn) == 3)
                return;

        /* Register to interrupt zero because we share the interrupt with
           the serial driver which we don't properly support yet.  */
        memset(&req, 0, sizeof(req));
        req.irq             = 0;
        req.flags           = IOC3_COM_FLAGS;
        req.io_type         = SERIAL_IO_MEM;
        req.iomem_reg_shift = 0;
        req.baud_base       = IOC3_BAUD;

        req.iomem_base      = (unsigned char *) &ioc3->sregs.uarta;
        register_serial(&req);

        req.iomem_base      = (unsigned char *) &ioc3->sregs.uartb;
        register_serial(&req);
}

static int __devinit ioc3_probe(struct pci_dev *pdev,
                                const struct pci_device_id *ent)
{
        unsigned int sw_physid1, sw_physid2;
        struct net_device *dev = NULL;
        struct ioc3_private *ip;
        struct ioc3 *ioc3;
        unsigned long ioc3_base, ioc3_size;
        u32 vendor, model, rev;
        int err;

        dev = alloc_etherdev(sizeof(struct ioc3_private));
        if (!dev)
                return -ENOMEM;

        err = pci_request_regions(pdev, "ioc3");
        if (err)
                goto out_free;

        SET_MODULE_OWNER(dev);
        SET_NETDEV_DEV(dev, &pdev->dev);

        ip = netdev_priv(dev);

        dev->irq = pdev->irq;

        ioc3_base = pci_resource_start(pdev, 0);
        ioc3_size = pci_resource_len(pdev, 0);
        ioc3 = (struct ioc3 *) ioremap(ioc3_base, ioc3_size);
        if (!ioc3) {
                printk(KERN_CRIT "ioc3eth(%s): ioremap failed, goodbye.\n",
                       pci_name(pdev));
                err = -ENOMEM;
                goto out_res;
        }
        ip->regs = ioc3;

#ifdef CONFIG_SERIAL_8250
        ioc3_serial_probe(pdev, ioc3);
#endif

        spin_lock_init(&ip->ioc3_lock);
        init_timer(&ip->ioc3_timer);

        ioc3_stop(ip);
        ioc3_init(dev);

        ip->pdev = pdev;

        ip->mii.phy_id_mask = 0x1f;
        ip->mii.reg_num_mask = 0x1f;
        ip->mii.dev = dev;
        ip->mii.mdio_read = ioc3_mdio_read;
        ip->mii.mdio_write = ioc3_mdio_write;

        ioc3_mii_init(ip);

        if (ip->mii.phy_id == -1) {
                printk(KERN_CRIT "ioc3-eth(%s): Didn't find a PHY, goodbye.\n",
                       pci_name(pdev));
                err = -ENODEV;
                goto out_stop;
        }

        ioc3_ssram_disc(ip);
        ioc3_get_eaddr(ip);

        /* The IOC3-specific entries in the device structure. */
        dev->open               = ioc3_open;
        dev->hard_start_xmit    = ioc3_start_xmit;
        dev->tx_timeout         = ioc3_timeout;
        dev->watchdog_timeo     = 5 * HZ;
        dev->stop               = ioc3_close;
        dev->get_stats          = ioc3_get_stats;
        dev->do_ioctl           = ioc3_ioctl;
        dev->set_multicast_list = ioc3_set_multicast_list;
        dev->ethtool_ops        = &ioc3_ethtool_ops;
#ifdef CONFIG_SGI_IOC3_ETH_HW_TX_CSUM
        dev->features           = NETIF_F_IP_CSUM;
#endif

        ioc3_setup_duplex(ip);
        sw_physid1 = ioc3_mdio_read(dev, ip->mii.phy_id, MII_PHYSID1);
        sw_physid2 = ioc3_mdio_read(dev, ip->mii.phy_id, MII_PHYSID2);

        err = register_netdev(dev);
        if (err)
                goto out_stop;

        mii_check_media(&ip->mii, 1, 1);

        vendor = (sw_physid1 << 12) | (sw_physid2 >> 4);
        model  = (sw_physid2 >> 4) & 0x3f;
        rev    = sw_physid2 & 0xf;
        printk(KERN_INFO "%s: Using PHY %d, vendor 0x%x, model %d, "
               "rev %d.\n", dev->name, ip->mii.phy_id, vendor, model, rev);
        printk(KERN_INFO "%s: IOC3 SSRAM has %d kbyte.\n", dev->name,
               ip->emcr & EMCR_BUFSIZ ? 128 : 64);

        return 0;

out_stop:
        ioc3_stop(ip);
        ioc3_free_rings(ip);
out_res:
        pci_release_regions(pdev);
out_free:
        free_netdev(dev);
        return err;
}

static void __devexit ioc3_remove_one (struct pci_dev *pdev)
{
        struct net_device *dev = pci_get_drvdata(pdev);
        struct ioc3_private *ip = netdev_priv(dev);
        struct ioc3 *ioc3 = ip->regs;

        unregister_netdev(dev);
        iounmap(ioc3);
        pci_release_regions(pdev);
        free_netdev(dev);
}

static struct pci_device_id ioc3_pci_tbl[] = {
        { PCI_VENDOR_ID_SGI, PCI_DEVICE_ID_SGI_IOC3, PCI_ANY_ID, PCI_ANY_ID },
        { 0 }
};
MODULE_DEVICE_TABLE(pci, ioc3_pci_tbl);

static struct pci_driver ioc3_driver = {
        .name           = "ioc3-eth",
        .id_table       = ioc3_pci_tbl,
        .probe          = ioc3_probe,
        .remove         = __devexit_p(ioc3_remove_one),
};

static int __init ioc3_init_module(void)
{
        return pci_module_init(&ioc3_driver);
}

static void __exit ioc3_cleanup_module(void)
{
        pci_unregister_driver(&ioc3_driver);
}

static int ioc3_start_xmit(struct sk_buff *skb, struct net_device *dev)
{
        unsigned long data;
        struct ioc3_private *ip = netdev_priv(dev);
        struct ioc3 *ioc3 = ip->regs;
        unsigned int len;
        struct ioc3_etxd *desc;
        uint32_t w0 = 0;
        int produce;

#ifdef CONFIG_SGI_IOC3_ETH_HW_TX_CSUM
        /*
         * IOC3 has a fairly simple minded checksumming hardware which simply
         * adds up the 1's complement checksum for the entire packet and
         * inserts it at an offset which can be specified in the descriptor
         * into the transmit packet.  This means we have to compensate for the
         * MAC header which should not be summed and the TCP/UDP pseudo headers
         * manually.
         */
        if (skb->ip_summed == CHECKSUM_HW) {
                int proto = ntohs(skb->nh.iph->protocol);
                unsigned int csoff;
                struct iphdr *ih = skb->nh.iph;
                uint32_t csum, ehsum;
                uint16_t *eh;

                /* The MAC header.  skb->mac seem the logic approach
                   to find the MAC header - except it's a NULL pointer ...  */
                eh = (uint16_t *) skb->data;

                /* Sum up dest addr, src addr and protocol  */
                ehsum = eh[0] + eh[1] + eh[2] + eh[3] + eh[4] + eh[5] + eh[6];

                /* Fold ehsum.  can't use csum_fold which negates also ...  */
                ehsum = (ehsum & 0xffff) + (ehsum >> 16);
                ehsum = (ehsum & 0xffff) + (ehsum >> 16);

                /* Skip IP header; it's sum is always zero and was
                   already filled in by ip_output.c */
                csum = csum_tcpudp_nofold(ih->saddr, ih->daddr,
                                          ih->tot_len - (ih->ihl << 2),
                                          proto, 0xffff ^ ehsum);

                csum = (csum & 0xffff) + (csum >> 16);  /* Fold again */
                csum = (csum & 0xffff) + (csum >> 16);

                csoff = ETH_HLEN + (ih->ihl << 2);
                if (proto == IPPROTO_UDP) {
                        csoff += offsetof(struct udphdr, check);
                        skb->h.uh->check = csum;
                }
                if (proto == IPPROTO_TCP) {
                        csoff += offsetof(struct tcphdr, check);
                        skb->h.th->check = csum;
                }

                w0 = ETXD_DOCHECKSUM | (csoff << ETXD_CHKOFF_SHIFT);
        }
#endif /* CONFIG_SGI_IOC3_ETH_HW_TX_CSUM */

        spin_lock_irq(&ip->ioc3_lock);

        data = (unsigned long) skb->data;
        len = skb->len;

        produce = ip->tx_pi;
        desc = &ip->txr[produce];

        if (len <= 104) {
                /* Short packet, let's copy it directly into the ring.  */
                memcpy(desc->data, skb->data, skb->len);
                if (len < ETH_ZLEN) {
                        /* Very short packet, pad with zeros at the end. */
                        memset(desc->data + len, 0, ETH_ZLEN - len);
                        len = ETH_ZLEN;
                }
                desc->cmd = cpu_to_be32(len | ETXD_INTWHENDONE | ETXD_D0V | w0);
                desc->bufcnt = cpu_to_be32(len);
        } else if ((data ^ (data + len - 1)) & 0x4000) {
                unsigned long b2 = (data | 0x3fffUL) + 1UL;
                unsigned long s1 = b2 - data;
                unsigned long s2 = data + len - b2;

                desc->cmd    = cpu_to_be32(len | ETXD_INTWHENDONE |
                                           ETXD_B1V | ETXD_B2V | w0);
                desc->bufcnt = cpu_to_be32((s1 << ETXD_B1CNT_SHIFT) |
                                           (s2 << ETXD_B2CNT_SHIFT));
                desc->p1     = cpu_to_be64(ioc3_map(skb->data, 1));
                desc->p2     = cpu_to_be64(ioc3_map((void *) b2, 1));
        } else {
                /* Normal sized packet that doesn't cross a page boundary. */
                desc->cmd = cpu_to_be32(len | ETXD_INTWHENDONE | ETXD_B1V | w0);
                desc->bufcnt = cpu_to_be32(len << ETXD_B1CNT_SHIFT);
                desc->p1     = cpu_to_be64(ioc3_map(skb->data, 1));
        }

        BARRIER();

        dev->trans_start = jiffies;
        ip->tx_skbs[produce] = skb;                     /* Remember skb */
        produce = (produce + 1) & 127;
        ip->tx_pi = produce;
        ioc3_w_etpir(produce << 7);                     /* Fire ... */

        ip->txqlen++;

        if (ip->txqlen >= 127)
                netif_stop_queue(dev);

        spin_unlock_irq(&ip->ioc3_lock);

        return 0;
}

static void ioc3_timeout(struct net_device *dev)
{
        struct ioc3_private *ip = netdev_priv(dev);

        printk(KERN_ERR "%s: transmit timed out, resetting\n", dev->name);

        spin_lock_irq(&ip->ioc3_lock);

        ioc3_stop(ip);
        ioc3_init(dev);
        ioc3_mii_init(ip);

        spin_unlock_irq(&ip->ioc3_lock);

        netif_wake_queue(dev);
}

/*
 * Given a multicast ethernet address, this routine calculates the
 * address's bit index in the logical address filter mask
 */

static inline unsigned int ioc3_hash(const unsigned char *addr)
{
        unsigned int temp = 0;
        u32 crc;
        int bits;

        crc = ether_crc_le(ETH_ALEN, addr);

        crc &= 0x3f;    /* bit reverse lowest 6 bits for hash index */
        for (bits = 6; --bits >= 0; ) {
                temp <<= 1;
                temp |= (crc & 0x1);
                crc >>= 1;
        }

        return temp;
}

static void ioc3_get_drvinfo (struct net_device *dev,
        struct ethtool_drvinfo *info)
{
        struct ioc3_private *ip = netdev_priv(dev);
                                                                                
        strcpy (info->driver, IOC3_NAME);
        strcpy (info->version, IOC3_VERSION);
        strcpy (info->bus_info, pci_name(ip->pdev));
}

static int ioc3_get_settings(struct net_device *dev, struct ethtool_cmd *cmd)
{
        struct ioc3_private *ip = netdev_priv(dev);
        int rc;

        spin_lock_irq(&ip->ioc3_lock);
        rc = mii_ethtool_gset(&ip->mii, cmd);
        spin_unlock_irq(&ip->ioc3_lock);

        return rc;
}

static int ioc3_set_settings(struct net_device *dev, struct ethtool_cmd *cmd)
{
        struct ioc3_private *ip = netdev_priv(dev);
        int rc;

        spin_lock_irq(&ip->ioc3_lock);
        rc = mii_ethtool_sset(&ip->mii, cmd);
        spin_unlock_irq(&ip->ioc3_lock);
                                                                        
        return rc;
}

static int ioc3_nway_reset(struct net_device *dev)
{
        struct ioc3_private *ip = netdev_priv(dev);
        int rc;

        spin_lock_irq(&ip->ioc3_lock);
        rc = mii_nway_restart(&ip->mii);
        spin_unlock_irq(&ip->ioc3_lock);

        return rc;
}

static u32 ioc3_get_link(struct net_device *dev)
{
        struct ioc3_private *ip = netdev_priv(dev);
        int rc;

        spin_lock_irq(&ip->ioc3_lock);
        rc = mii_link_ok(&ip->mii);
        spin_unlock_irq(&ip->ioc3_lock);

        return rc;
}

static struct ethtool_ops ioc3_ethtool_ops = {
        .get_drvinfo            = ioc3_get_drvinfo,
        .get_settings           = ioc3_get_settings,
        .set_settings           = ioc3_set_settings,
        .nway_reset             = ioc3_nway_reset,
        .get_link               = ioc3_get_link,
};

static int ioc3_ioctl(struct net_device *dev, struct ifreq *rq, int cmd)
{
        struct ioc3_private *ip = netdev_priv(dev);
        int rc;

        spin_lock_irq(&ip->ioc3_lock);
        rc = generic_mii_ioctl(&ip->mii, if_mii(rq), cmd, NULL);
        spin_unlock_irq(&ip->ioc3_lock);

        return rc;
}

static void ioc3_set_multicast_list(struct net_device *dev)
{
        struct dev_mc_list *dmi = dev->mc_list;
        struct ioc3_private *ip = netdev_priv(dev);
        struct ioc3 *ioc3 = ip->regs;
        u64 ehar = 0;
        int i;

        netif_stop_queue(dev);                          /* Lock out others. */

        if (dev->flags & IFF_PROMISC) {                 /* Set promiscuous.  */
                /* Unconditionally log net taps.  */
                printk(KERN_INFO "%s: Promiscuous mode enabled.\n", dev->name);
                ip->emcr |= EMCR_PROMISC;
                ioc3_w_emcr(ip->emcr);
                (void) ioc3_r_emcr();
        } else {
                ip->emcr &= ~EMCR_PROMISC;
                ioc3_w_emcr(ip->emcr);                  /* Clear promiscuous. */
                (void) ioc3_r_emcr();

                if ((dev->flags & IFF_ALLMULTI) || (dev->mc_count > 64)) {
                        /* Too many for hashing to make sense or we want all
                           multicast packets anyway,  so skip computing all the
                           hashes and just accept all packets.  */
                        ip->ehar_h = 0xffffffff;
                        ip->ehar_l = 0xffffffff;
                } else {
                        for (i = 0; i < dev->mc_count; i++) {
                                char *addr = dmi->dmi_addr;
                                dmi = dmi->next;

                                if (!(*addr & 1))
                                        continue;

                                ehar |= (1UL << ioc3_hash(addr));
                        }
                        ip->ehar_h = ehar >> 32;
                        ip->ehar_l = ehar & 0xffffffff;
                }
                ioc3_w_ehar_h(ip->ehar_h);
                ioc3_w_ehar_l(ip->ehar_l);
        }

        netif_wake_queue(dev);                  /* Let us get going again. */
}

MODULE_AUTHOR("Ralf Baechle <ralf@linux-mips.org>");
MODULE_DESCRIPTION("SGI IOC3 Ethernet driver");
MODULE_LICENSE("GPL");

module_init(ioc3_init_module);
module_exit(ioc3_cleanup_module);