sgiseeq.c

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/*
 * sgiseeq.c: Seeq8003 ethernet driver for SGI machines.
 *
 * Copyright (C) 1996 David S. Miller ([email protected])
 */

#undef DEBUG

#include <linux/dma-mapping.h>
#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/slab.h>
#include <linux/errno.h>
#include <linux/init.h>
#include <linux/types.h>
#include <linux/interrupt.h>
#include <linux/string.h>
#include <linux/delay.h>
#include <linux/netdevice.h>
#include <linux/platform_device.h>
#include <linux/etherdevice.h>
#include <linux/skbuff.h>

#include <asm/sgi/hpc3.h>
#include <asm/sgi/ip22.h>
#include <asm/sgi/seeq.h>

#include "sgiseeq.h"

static char *sgiseeqstr = "SGI Seeq8003";

/*
 * If you want speed, you do something silly, it always has worked for me.  So,
 * with that in mind, I've decided to make this driver look completely like a
 * stupid Lance from a driver architecture perspective.  Only difference is that
 * here our "ring buffer" looks and acts like a real Lance one does but is
 * laid out like how the HPC DMA and the Seeq want it to.  You'd be surprised
 * how a stupid idea like this can pay off in performance, not to mention
 * making this driver 2,000 times easier to write. ;-)
 */

/* Tune these if we tend to run out often etc. */
#define SEEQ_RX_BUFFERS  16
#define SEEQ_TX_BUFFERS  16

#define PKT_BUF_SZ       1584

#define NEXT_RX(i)  (((i) + 1) & (SEEQ_RX_BUFFERS - 1))
#define NEXT_TX(i)  (((i) + 1) & (SEEQ_TX_BUFFERS - 1))
#define PREV_RX(i)  (((i) - 1) & (SEEQ_RX_BUFFERS - 1))
#define PREV_TX(i)  (((i) - 1) & (SEEQ_TX_BUFFERS - 1))

#define TX_BUFFS_AVAIL(sp) ((sp->tx_old <= sp->tx_new) ? \
                sp->tx_old + (SEEQ_TX_BUFFERS - 1) - sp->tx_new : \
                sp->tx_old - sp->tx_new - 1)

#define VIRT_TO_DMA(sp, v) ((sp)->srings_dma +                                 \
                  (dma_addr_t)((unsigned long)(v) -            \
                           (unsigned long)((sp)->rx_desc)))

/* Copy frames shorter than rx_copybreak, otherwise pass on up in
 * a full sized sk_buff.  Value of 100 stolen from tulip.c (!alpha).
 */
static int rx_copybreak = 100;

#define PAD_SIZE    (128 - sizeof(struct hpc_dma_desc) - sizeof(void *))

struct sgiseeq_rx_desc {
    volatile struct hpc_dma_desc rdma;
    u8 padding[PAD_SIZE];
    struct sk_buff *skb;
};

struct sgiseeq_tx_desc {
    volatile struct hpc_dma_desc tdma;
    u8 padding[PAD_SIZE];
    struct sk_buff *skb;
};

/*
 * Warning: This structure is laid out in a certain way because HPC dma
 *          descriptors must be 8-byte aligned.  So don't touch this without
 *          some care.
 */
struct sgiseeq_init_block { /* Note the name ;-) */
    struct sgiseeq_rx_desc rxvector[SEEQ_RX_BUFFERS];
    struct sgiseeq_tx_desc txvector[SEEQ_TX_BUFFERS];
};

struct sgiseeq_private {
    struct sgiseeq_init_block *srings;
    dma_addr_t srings_dma;

    /* Ptrs to the descriptors in uncached space. */
    struct sgiseeq_rx_desc *rx_desc;
    struct sgiseeq_tx_desc *tx_desc;

    char *name;
    struct hpc3_ethregs *hregs;
    struct sgiseeq_regs *sregs;

    /* Ring entry counters. */
    unsigned int rx_new, tx_new;
    unsigned int rx_old, tx_old;

    int is_edlc;
    unsigned char control;
    unsigned char mode;

    spinlock_t tx_lock;
};

static inline void dma_sync_desc_cpu(struct net_device *dev, void *addr)
{
    dma_cache_sync(dev->dev.parent, addr, sizeof(struct sgiseeq_rx_desc),
               DMA_FROM_DEVICE);
}

static inline void dma_sync_desc_dev(struct net_device *dev, void *addr)
{
    dma_cache_sync(dev->dev.parent, addr, sizeof(struct sgiseeq_rx_desc),
               DMA_TO_DEVICE);
}

static inline void hpc3_eth_reset(struct hpc3_ethregs *hregs)
{
    hregs->reset = HPC3_ERST_CRESET | HPC3_ERST_CLRIRQ;
    udelay(20);
    hregs->reset = 0;
}

static inline void reset_hpc3_and_seeq(struct hpc3_ethregs *hregs,
                       struct sgiseeq_regs *sregs)
{
    hregs->rx_ctrl = hregs->tx_ctrl = 0;
    hpc3_eth_reset(hregs);
}

#define RSTAT_GO_BITS (SEEQ_RCMD_IGOOD | SEEQ_RCMD_IEOF | SEEQ_RCMD_ISHORT | \
               SEEQ_RCMD_IDRIB | SEEQ_RCMD_ICRC)

static inline void seeq_go(struct sgiseeq_private *sp,
               struct hpc3_ethregs *hregs,
               struct sgiseeq_regs *sregs)
{
    sregs->rstat = sp->mode | RSTAT_GO_BITS;
    hregs->rx_ctrl = HPC3_ERXCTRL_ACTIVE;
}

static inline void __sgiseeq_set_mac_address(struct net_device *dev)
{
    struct sgiseeq_private *sp = netdev_priv(dev);
    struct sgiseeq_regs *sregs = sp->sregs;
    int i;

    sregs->tstat = SEEQ_TCMD_RB0;
    for (i = 0; i < 6; i++)
        sregs->rw.eth_addr[i] = dev->dev_addr[i];
}

static int sgiseeq_set_mac_address(struct net_device *dev, void *addr)
{
    struct sgiseeq_private *sp = netdev_priv(dev);
    struct sockaddr *sa = addr;

    memcpy(dev->dev_addr, sa->sa_data, dev->addr_len);

    spin_lock_irq(&sp->tx_lock);
    __sgiseeq_set_mac_address(dev);
    spin_unlock_irq(&sp->tx_lock);

    return 0;
}

#define TCNTINFO_INIT (HPCDMA_EOX | HPCDMA_ETXD)
#define RCNTCFG_INIT  (HPCDMA_OWN | HPCDMA_EORP | HPCDMA_XIE)
#define RCNTINFO_INIT (RCNTCFG_INIT | (PKT_BUF_SZ & HPCDMA_BCNT))

static int seeq_init_ring(struct net_device *dev)
{
    struct sgiseeq_private *sp = netdev_priv(dev);
    int i;

    netif_stop_queue(dev);
    sp->rx_new = sp->tx_new = 0;
    sp->rx_old = sp->tx_old = 0;

    __sgiseeq_set_mac_address(dev);

    /* Setup tx ring. */
    for(i = 0; i < SEEQ_TX_BUFFERS; i++) {
        sp->tx_desc[i].tdma.cntinfo = TCNTINFO_INIT;
        dma_sync_desc_dev(dev, &sp->tx_desc[i]);
    }

    /* And now the rx ring. */
    for (i = 0; i < SEEQ_RX_BUFFERS; i++) {
        if (!sp->rx_desc[i].skb) {
            dma_addr_t dma_addr;
            struct sk_buff *skb = netdev_alloc_skb(dev, PKT_BUF_SZ);

            if (skb == NULL)
                return -ENOMEM;
            skb_reserve(skb, 2);
            dma_addr = dma_map_single(dev->dev.parent,
                          skb->data - 2,
                          PKT_BUF_SZ, DMA_FROM_DEVICE);
            sp->rx_desc[i].skb = skb;
            sp->rx_desc[i].rdma.pbuf = dma_addr;
        }
        sp->rx_desc[i].rdma.cntinfo = RCNTINFO_INIT;
        dma_sync_desc_dev(dev, &sp->rx_desc[i]);
    }
    sp->rx_desc[i - 1].rdma.cntinfo |= HPCDMA_EOR;
    dma_sync_desc_dev(dev, &sp->rx_desc[i - 1]);
    return 0;
}

static void seeq_purge_ring(struct net_device *dev)
{
    struct sgiseeq_private *sp = netdev_priv(dev);
    int i;

    /* clear tx ring. */
    for (i = 0; i < SEEQ_TX_BUFFERS; i++) {
        if (sp->tx_desc[i].skb) {
            dev_kfree_skb(sp->tx_desc[i].skb);
            sp->tx_desc[i].skb = NULL;
        }
    }

    /* And now the rx ring. */
    for (i = 0; i < SEEQ_RX_BUFFERS; i++) {
        if (sp->rx_desc[i].skb) {
            dev_kfree_skb(sp->rx_desc[i].skb);
            sp->rx_desc[i].skb = NULL;
        }
    }
}

#ifdef DEBUG
static struct sgiseeq_private *gpriv;
static struct net_device *gdev;

static void sgiseeq_dump_rings(void)
{
    static int once;
    struct sgiseeq_rx_desc *r = gpriv->rx_desc;
    struct sgiseeq_tx_desc *t = gpriv->tx_desc;
    struct hpc3_ethregs *hregs = gpriv->hregs;
    int i;

    if (once)
        return;
    once++;
    printk("RING DUMP:\n");
    for (i = 0; i < SEEQ_RX_BUFFERS; i++) {
        printk("RX [%d]: @(%p) [%08x,%08x,%08x] ",
               i, (&r[i]), r[i].rdma.pbuf, r[i].rdma.cntinfo,
               r[i].rdma.pnext);
        i += 1;
        printk("-- [%d]: @(%p) [%08x,%08x,%08x]\n",
               i, (&r[i]), r[i].rdma.pbuf, r[i].rdma.cntinfo,
               r[i].rdma.pnext);
    }
    for (i = 0; i < SEEQ_TX_BUFFERS; i++) {
        printk("TX [%d]: @(%p) [%08x,%08x,%08x] ",
               i, (&t[i]), t[i].tdma.pbuf, t[i].tdma.cntinfo,
               t[i].tdma.pnext);
        i += 1;
        printk("-- [%d]: @(%p) [%08x,%08x,%08x]\n",
               i, (&t[i]), t[i].tdma.pbuf, t[i].tdma.cntinfo,
               t[i].tdma.pnext);
    }
    printk("INFO: [rx_new = %d rx_old=%d] [tx_new = %d tx_old = %d]\n",
           gpriv->rx_new, gpriv->rx_old, gpriv->tx_new, gpriv->tx_old);
    printk("RREGS: rx_cbptr[%08x] rx_ndptr[%08x] rx_ctrl[%08x]\n",
           hregs->rx_cbptr, hregs->rx_ndptr, hregs->rx_ctrl);
    printk("TREGS: tx_cbptr[%08x] tx_ndptr[%08x] tx_ctrl[%08x]\n",
           hregs->tx_cbptr, hregs->tx_ndptr, hregs->tx_ctrl);
}
#endif

#define TSTAT_INIT_SEEQ (SEEQ_TCMD_IPT|SEEQ_TCMD_I16|SEEQ_TCMD_IC|SEEQ_TCMD_IUF)
#define TSTAT_INIT_EDLC ((TSTAT_INIT_SEEQ) | SEEQ_TCMD_RB2)

static int init_seeq(struct net_device *dev, struct sgiseeq_private *sp,
             struct sgiseeq_regs *sregs)
{
    struct hpc3_ethregs *hregs = sp->hregs;
    int err;

    reset_hpc3_and_seeq(hregs, sregs);
    err = seeq_init_ring(dev);
    if (err)
        return err;

    /* Setup to field the proper interrupt types. */
    if (sp->is_edlc) {
        sregs->tstat = TSTAT_INIT_EDLC;
        sregs->rw.wregs.control = sp->control;
        sregs->rw.wregs.frame_gap = 0;
    } else {
        sregs->tstat = TSTAT_INIT_SEEQ;
    }

    hregs->rx_ndptr = VIRT_TO_DMA(sp, sp->rx_desc);
    hregs->tx_ndptr = VIRT_TO_DMA(sp, sp->tx_desc);

    seeq_go(sp, hregs, sregs);
    return 0;
}

static void record_rx_errors(struct net_device *dev, unsigned char status)
{
    if (status & SEEQ_RSTAT_OVERF ||
        status & SEEQ_RSTAT_SFRAME)
        dev->stats.rx_over_errors++;
    if (status & SEEQ_RSTAT_CERROR)
        dev->stats.rx_crc_errors++;
    if (status & SEEQ_RSTAT_DERROR)
        dev->stats.rx_frame_errors++;
    if (status & SEEQ_RSTAT_REOF)
        dev->stats.rx_errors++;
}

static inline void rx_maybe_restart(struct sgiseeq_private *sp,
                    struct hpc3_ethregs *hregs,
                    struct sgiseeq_regs *sregs)
{
    if (!(hregs->rx_ctrl & HPC3_ERXCTRL_ACTIVE)) {
        hregs->rx_ndptr = VIRT_TO_DMA(sp, sp->rx_desc + sp->rx_new);
        seeq_go(sp, hregs, sregs);
    }
}

static inline void sgiseeq_rx(struct net_device *dev, struct sgiseeq_private *sp,
                  struct hpc3_ethregs *hregs,
                  struct sgiseeq_regs *sregs)
{
    struct sgiseeq_rx_desc *rd;
    struct sk_buff *skb = NULL;
    struct sk_buff *newskb;
    unsigned char pkt_status;
    int len = 0;
    unsigned int orig_end = PREV_RX(sp->rx_new);

    /* Service every received packet. */
    rd = &sp->rx_desc[sp->rx_new];
    dma_sync_desc_cpu(dev, rd);
    while (!(rd->rdma.cntinfo & HPCDMA_OWN)) {
        len = PKT_BUF_SZ - (rd->rdma.cntinfo & HPCDMA_BCNT) - 3;
        dma_unmap_single(dev->dev.parent, rd->rdma.pbuf,
                 PKT_BUF_SZ, DMA_FROM_DEVICE);
        pkt_status = rd->skb->data[len];
        if (pkt_status & SEEQ_RSTAT_FIG) {
            /* Packet is OK. */
            /* We don't want to receive our own packets */
            if (memcmp(rd->skb->data + 6, dev->dev_addr, ETH_ALEN)) {
                if (len > rx_copybreak) {
                    skb = rd->skb;
                    newskb = netdev_alloc_skb(dev, PKT_BUF_SZ);
                    if (!newskb) {
                        newskb = skb;
                        skb = NULL;
                        goto memory_squeeze;
                    }
                    skb_reserve(newskb, 2);
                } else {
                    skb = netdev_alloc_skb_ip_align(dev, len);
                    if (skb)
                        skb_copy_to_linear_data(skb, rd->skb->data, len);

                    newskb = rd->skb;
                }
memory_squeeze:
                if (skb) {
                    skb_put(skb, len);
                    skb->protocol = eth_type_trans(skb, dev);
                    netif_rx(skb);
                    dev->stats.rx_packets++;
                    dev->stats.rx_bytes += len;
                } else {
                    printk(KERN_NOTICE "%s: Memory squeeze, deferring packet.\n",
                        dev->name);
                    dev->stats.rx_dropped++;
                }
            } else {
                /* Silently drop my own packets */
                newskb = rd->skb;
            }
        } else {
            record_rx_errors(dev, pkt_status);
            newskb = rd->skb;
        }
        rd->skb = newskb;
        rd->rdma.pbuf = dma_map_single(dev->dev.parent,
                           newskb->data - 2,
                           PKT_BUF_SZ, DMA_FROM_DEVICE);

        /* Return the entry to the ring pool. */
        rd->rdma.cntinfo = RCNTINFO_INIT;
        sp->rx_new = NEXT_RX(sp->rx_new);
        dma_sync_desc_dev(dev, rd);
        rd = &sp->rx_desc[sp->rx_new];
        dma_sync_desc_cpu(dev, rd);
    }
    dma_sync_desc_cpu(dev, &sp->rx_desc[orig_end]);
    sp->rx_desc[orig_end].rdma.cntinfo &= ~(HPCDMA_EOR);
    dma_sync_desc_dev(dev, &sp->rx_desc[orig_end]);
    dma_sync_desc_cpu(dev, &sp->rx_desc[PREV_RX(sp->rx_new)]);
    sp->rx_desc[PREV_RX(sp->rx_new)].rdma.cntinfo |= HPCDMA_EOR;
    dma_sync_desc_dev(dev, &sp->rx_desc[PREV_RX(sp->rx_new)]);
    rx_maybe_restart(sp, hregs, sregs);
}

static inline void tx_maybe_reset_collisions(struct sgiseeq_private *sp,
                         struct sgiseeq_regs *sregs)
{
    if (sp->is_edlc) {
        sregs->rw.wregs.control = sp->control & ~(SEEQ_CTRL_XCNT);
        sregs->rw.wregs.control = sp->control;
    }
}

static inline void kick_tx(struct net_device *dev,
               struct sgiseeq_private *sp,
               struct hpc3_ethregs *hregs)
{
    struct sgiseeq_tx_desc *td;
    int i = sp->tx_old;

    /* If the HPC aint doin nothin, and there are more packets
     * with ETXD cleared and XIU set we must make very certain
     * that we restart the HPC else we risk locking up the
     * adapter.  The following code is only safe iff the HPCDMA
     * is not active!
     */
    td = &sp->tx_desc[i];
    dma_sync_desc_cpu(dev, td);
    while ((td->tdma.cntinfo & (HPCDMA_XIU | HPCDMA_ETXD)) ==
          (HPCDMA_XIU | HPCDMA_ETXD)) {
        i = NEXT_TX(i);
        td = &sp->tx_desc[i];
        dma_sync_desc_cpu(dev, td);
    }
    if (td->tdma.cntinfo & HPCDMA_XIU) {
        hregs->tx_ndptr = VIRT_TO_DMA(sp, td);
        hregs->tx_ctrl = HPC3_ETXCTRL_ACTIVE;
    }
}

static inline void sgiseeq_tx(struct net_device *dev, struct sgiseeq_private *sp,
                  struct hpc3_ethregs *hregs,
                  struct sgiseeq_regs *sregs)
{
    struct sgiseeq_tx_desc *td;
    unsigned long status = hregs->tx_ctrl;
    int j;

    tx_maybe_reset_collisions(sp, sregs);

    if (!(status & (HPC3_ETXCTRL_ACTIVE | SEEQ_TSTAT_PTRANS))) {
        /* Oops, HPC detected some sort of error. */
        if (status & SEEQ_TSTAT_R16)
            dev->stats.tx_aborted_errors++;
        if (status & SEEQ_TSTAT_UFLOW)
            dev->stats.tx_fifo_errors++;
        if (status & SEEQ_TSTAT_LCLS)
            dev->stats.collisions++;
    }

    /* Ack 'em... */
    for (j = sp->tx_old; j != sp->tx_new; j = NEXT_TX(j)) {
        td = &sp->tx_desc[j];

        dma_sync_desc_cpu(dev, td);
        if (!(td->tdma.cntinfo & (HPCDMA_XIU)))
            break;
        if (!(td->tdma.cntinfo & (HPCDMA_ETXD))) {
            if (!(status & HPC3_ETXCTRL_ACTIVE)) {
                hregs->tx_ndptr = VIRT_TO_DMA(sp, td);
                hregs->tx_ctrl = HPC3_ETXCTRL_ACTIVE;
            }
            break;
        }
        dev->stats.tx_packets++;
        sp->tx_old = NEXT_TX(sp->tx_old);
        td->tdma.cntinfo &= ~(HPCDMA_XIU | HPCDMA_XIE);
        td->tdma.cntinfo |= HPCDMA_EOX;
        if (td->skb) {
            dev_kfree_skb_any(td->skb);
            td->skb = NULL;
        }
        dma_sync_desc_dev(dev, td);
    }
}

static irqreturn_t sgiseeq_interrupt(int irq, void *dev_id)
{
    struct net_device *dev = (struct net_device *) dev_id;
    struct sgiseeq_private *sp = netdev_priv(dev);
    struct hpc3_ethregs *hregs = sp->hregs;
    struct sgiseeq_regs *sregs = sp->sregs;

    spin_lock(&sp->tx_lock);

    /* Ack the IRQ and set software state. */
    hregs->reset = HPC3_ERST_CLRIRQ;

    /* Always check for received packets. */
    sgiseeq_rx(dev, sp, hregs, sregs);

    /* Only check for tx acks if we have something queued. */
    if (sp->tx_old != sp->tx_new)
        sgiseeq_tx(dev, sp, hregs, sregs);

    if ((TX_BUFFS_AVAIL(sp) > 0) && netif_queue_stopped(dev)) {
        netif_wake_queue(dev);
    }
    spin_unlock(&sp->tx_lock);

    return IRQ_HANDLED;
}

static int sgiseeq_open(struct net_device *dev)
{
    struct sgiseeq_private *sp = netdev_priv(dev);
    struct sgiseeq_regs *sregs = sp->sregs;
    unsigned int irq = dev->irq;
    int err;

    if (request_irq(irq, sgiseeq_interrupt, 0, sgiseeqstr, dev)) {
        printk(KERN_ERR "Seeq8003: Can't get irq %d\n", dev->irq);
        return -EAGAIN;
    }

    err = init_seeq(dev, sp, sregs);
    if (err)
        goto out_free_irq;

    netif_start_queue(dev);

    return 0;

out_free_irq:
    free_irq(irq, dev);

    return err;
}

static int sgiseeq_close(struct net_device *dev)
{
    struct sgiseeq_private *sp = netdev_priv(dev);
    struct sgiseeq_regs *sregs = sp->sregs;
    unsigned int irq = dev->irq;

    netif_stop_queue(dev);

    /* Shutdown the Seeq. */
    reset_hpc3_and_seeq(sp->hregs, sregs);
    free_irq(irq, dev);
    seeq_purge_ring(dev);

    return 0;
}

static inline int sgiseeq_reset(struct net_device *dev)
{
    struct sgiseeq_private *sp = netdev_priv(dev);
    struct sgiseeq_regs *sregs = sp->sregs;
    int err;

    err = init_seeq(dev, sp, sregs);
    if (err)
        return err;

    dev->trans_start = jiffies; /* prevent tx timeout */
    netif_wake_queue(dev);

    return 0;
}

static int sgiseeq_start_xmit(struct sk_buff *skb, struct net_device *dev)
{
    struct sgiseeq_private *sp = netdev_priv(dev);
    struct hpc3_ethregs *hregs = sp->hregs;
    unsigned long flags;
    struct sgiseeq_tx_desc *td;
    int len, entry;

    spin_lock_irqsave(&sp->tx_lock, flags);

    /* Setup... */
    len = skb->len;
    if (len < ETH_ZLEN) {
        if (skb_padto(skb, ETH_ZLEN)) {
            spin_unlock_irqrestore(&sp->tx_lock, flags);
            return NETDEV_TX_OK;
        }
        len = ETH_ZLEN;
    }

    dev->stats.tx_bytes += len;
    entry = sp->tx_new;
    td = &sp->tx_desc[entry];
    dma_sync_desc_cpu(dev, td);

    /* Create entry.  There are so many races with adding a new
     * descriptor to the chain:
     * 1) Assume that the HPC is off processing a DMA chain while
     *    we are changing all of the following.
     * 2) Do no allow the HPC to look at a new descriptor until
     *    we have completely set up it's state.  This means, do
     *    not clear HPCDMA_EOX in the current last descritptor
     *    until the one we are adding looks consistent and could
     *    be processes right now.
     * 3) The tx interrupt code must notice when we've added a new
     *    entry and the HPC got to the end of the chain before we
     *    added this new entry and restarted it.
     */
    td->skb = skb;
    td->tdma.pbuf = dma_map_single(dev->dev.parent, skb->data,
                       len, DMA_TO_DEVICE);
    td->tdma.cntinfo = (len & HPCDMA_BCNT) |
                       HPCDMA_XIU | HPCDMA_EOXP | HPCDMA_XIE | HPCDMA_EOX;
    dma_sync_desc_dev(dev, td);
    if (sp->tx_old != sp->tx_new) {
        struct sgiseeq_tx_desc *backend;

        backend = &sp->tx_desc[PREV_TX(sp->tx_new)];
        dma_sync_desc_cpu(dev, backend);
        backend->tdma.cntinfo &= ~HPCDMA_EOX;
        dma_sync_desc_dev(dev, backend);
    }
    sp->tx_new = NEXT_TX(sp->tx_new); /* Advance. */

    /* Maybe kick the HPC back into motion. */
    if (!(hregs->tx_ctrl & HPC3_ETXCTRL_ACTIVE))
        kick_tx(dev, sp, hregs);

    if (!TX_BUFFS_AVAIL(sp))
        netif_stop_queue(dev);
    spin_unlock_irqrestore(&sp->tx_lock, flags);

    return NETDEV_TX_OK;
}

static void timeout(struct net_device *dev)
{
    printk(KERN_NOTICE "%s: transmit timed out, resetting\n", dev->name);
    sgiseeq_reset(dev);

    dev->trans_start = jiffies; /* prevent tx timeout */
    netif_wake_queue(dev);
}

static void sgiseeq_set_multicast(struct net_device *dev)
{
    struct sgiseeq_private *sp = netdev_priv(dev);
    unsigned char oldmode = sp->mode;

    if(dev->flags & IFF_PROMISC)
        sp->mode = SEEQ_RCMD_RANY;
    else if ((dev->flags & IFF_ALLMULTI) || !netdev_mc_empty(dev))
        sp->mode = SEEQ_RCMD_RBMCAST;
    else
        sp->mode = SEEQ_RCMD_RBCAST;

    /* XXX I know this sucks, but is there a better way to reprogram
     * XXX the receiver? At least, this shouldn't happen too often.
     */

    if (oldmode != sp->mode)
        sgiseeq_reset(dev);
}

static inline void setup_tx_ring(struct net_device *dev,
                 struct sgiseeq_tx_desc *buf,
                 int nbufs)
{
    struct sgiseeq_private *sp = netdev_priv(dev);
    int i = 0;

    while (i < (nbufs - 1)) {
        buf[i].tdma.pnext = VIRT_TO_DMA(sp, buf + i + 1);
        buf[i].tdma.pbuf = 0;
        dma_sync_desc_dev(dev, &buf[i]);
        i++;
    }
    buf[i].tdma.pnext = VIRT_TO_DMA(sp, buf);
    dma_sync_desc_dev(dev, &buf[i]);
}

static inline void setup_rx_ring(struct net_device *dev,
                 struct sgiseeq_rx_desc *buf,
                 int nbufs)
{
    struct sgiseeq_private *sp = netdev_priv(dev);
    int i = 0;

    while (i < (nbufs - 1)) {
        buf[i].rdma.pnext = VIRT_TO_DMA(sp, buf + i + 1);
        buf[i].rdma.pbuf = 0;
        dma_sync_desc_dev(dev, &buf[i]);
        i++;
    }
    buf[i].rdma.pbuf = 0;
    buf[i].rdma.pnext = VIRT_TO_DMA(sp, buf);
    dma_sync_desc_dev(dev, &buf[i]);
}

static const struct net_device_ops sgiseeq_netdev_ops = {
    .ndo_open       = sgiseeq_open,
    .ndo_stop       = sgiseeq_close,
    .ndo_start_xmit     = sgiseeq_start_xmit,
    .ndo_tx_timeout     = timeout,
    .ndo_set_rx_mode    = sgiseeq_set_multicast,
    .ndo_set_mac_address    = sgiseeq_set_mac_address,
    .ndo_change_mtu     = eth_change_mtu,
    .ndo_validate_addr  = eth_validate_addr,
};

static int __devinit sgiseeq_probe(struct platform_device *pdev)
{
    struct sgiseeq_platform_data *pd = pdev->dev.platform_data;
    struct hpc3_regs *hpcregs = pd->hpc;
    struct sgiseeq_init_block *sr;
    unsigned int irq = pd->irq;
    struct sgiseeq_private *sp;
    struct net_device *dev;
    int err;

    dev = alloc_etherdev(sizeof (struct sgiseeq_private));
    if (!dev) {
        err = -ENOMEM;
        goto err_out;
    }

    platform_set_drvdata(pdev, dev);
    sp = netdev_priv(dev);

    /* Make private data page aligned */
    sr = dma_alloc_noncoherent(&pdev->dev, sizeof(*sp->srings),
                &sp->srings_dma, GFP_KERNEL);
    if (!sr) {
        printk(KERN_ERR "Sgiseeq: Page alloc failed, aborting.\n");
        err = -ENOMEM;
        goto err_out_free_dev;
    }
    sp->srings = sr;
    sp->rx_desc = sp->srings->rxvector;
    sp->tx_desc = sp->srings->txvector;
    spin_lock_init(&sp->tx_lock);

    /* A couple calculations now, saves many cycles later. */
    setup_rx_ring(dev, sp->rx_desc, SEEQ_RX_BUFFERS);
    setup_tx_ring(dev, sp->tx_desc, SEEQ_TX_BUFFERS);

    memcpy(dev->dev_addr, pd->mac, ETH_ALEN);

#ifdef DEBUG
    gpriv = sp;
    gdev = dev;
#endif
    sp->sregs = (struct sgiseeq_regs *) &hpcregs->eth_ext[0];
    sp->hregs = &hpcregs->ethregs;
    sp->name = sgiseeqstr;
    sp->mode = SEEQ_RCMD_RBCAST;

    /* Setup PIO and DMA transfer timing */
    sp->hregs->pconfig = 0x161;
    sp->hregs->dconfig = HPC3_EDCFG_FIRQ | HPC3_EDCFG_FEOP |
                 HPC3_EDCFG_FRXDC | HPC3_EDCFG_PTO | 0x026;

    /* Setup PIO and DMA transfer timing */
    sp->hregs->pconfig = 0x161;
    sp->hregs->dconfig = HPC3_EDCFG_FIRQ | HPC3_EDCFG_FEOP |
                 HPC3_EDCFG_FRXDC | HPC3_EDCFG_PTO | 0x026;

    /* Reset the chip. */
    hpc3_eth_reset(sp->hregs);

    sp->is_edlc = !(sp->sregs->rw.rregs.collision_tx[0] & 0xff);
    if (sp->is_edlc)
        sp->control = SEEQ_CTRL_XCNT | SEEQ_CTRL_ACCNT |
                  SEEQ_CTRL_SFLAG | SEEQ_CTRL_ESHORT |
                  SEEQ_CTRL_ENCARR;

    dev->netdev_ops     = &sgiseeq_netdev_ops;
    dev->watchdog_timeo = (200 * HZ) / 1000;
    dev->irq        = irq;

    if (register_netdev(dev)) {
        printk(KERN_ERR "Sgiseeq: Cannot register net device, "
               "aborting.\n");
        err = -ENODEV;
        goto err_out_free_page;
    }

    printk(KERN_INFO "%s: %s %pM\n", dev->name, sgiseeqstr, dev->dev_addr);

    return 0;

err_out_free_page:
    free_page((unsigned long) sp->srings);
err_out_free_dev:
    free_netdev(dev);

err_out:
    return err;
}

static int __exit sgiseeq_remove(struct platform_device *pdev)
{
    struct net_device *dev = platform_get_drvdata(pdev);
    struct sgiseeq_private *sp = netdev_priv(dev);

    unregister_netdev(dev);
    dma_free_noncoherent(&pdev->dev, sizeof(*sp->srings), sp->srings,
                 sp->srings_dma);
    free_netdev(dev);
    platform_set_drvdata(pdev, NULL);

    return 0;
}

static struct platform_driver sgiseeq_driver = {
    .probe  = sgiseeq_probe,
    .remove = __exit_p(sgiseeq_remove),
    .driver = {
        .name   = "sgiseeq",
        .owner  = THIS_MODULE,
    }
};

module_platform_driver(sgiseeq_driver);

MODULE_DESCRIPTION("SGI Seeq 8003 driver");
MODULE_AUTHOR("Linux/MIPS Mailing List <[email protected]>");
MODULE_LICENSE("GPL");
MODULE_ALIAS("platform:sgiseeq");