Adding upstream version 6.1.76.upstream/6.1.76

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

1 files changed, 848 insertions, 0 deletions

diff --git a/drivers/net/ethernet/seeq/sgiseeq.c b/drivers/net/ethernet/seeq/sgiseeq.c
new file mode 100644
index 000000000..96065dfc7
--- /dev/null
+++ b/drivers/net/ethernet/seeq/sgiseeq.c
@@ -0,0 +1,848 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * sgiseeq.c: Seeq8003 ethernet driver for SGI machines.
+ *
+ * Copyright (C) 1996 David S. Miller (davem@davemloft.net)
+ */
+
+#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/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)
+{
+	struct sgiseeq_private *sp = netdev_priv(dev);
+
+	dma_sync_single_for_cpu(dev->dev.parent, VIRT_TO_DMA(sp, addr),
+			sizeof(struct sgiseeq_rx_desc), DMA_BIDIRECTIONAL);
+}
+
+static inline void dma_sync_desc_dev(struct net_device *dev, void *addr)
+{
+	struct sgiseeq_private *sp = netdev_priv(dev);
+
+	dma_sync_single_for_device(dev->dev.parent, VIRT_TO_DMA(sp, addr),
+			sizeof(struct sgiseeq_rx_desc), DMA_BIDIRECTIONAL);
+}
+
+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;
+
+	eth_hw_addr_set(dev, sa->sa_data);
+
+	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 (!ether_addr_equal(rd->skb->data + 6, dev->dev_addr)) {
+				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 {
+					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_dev(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) {
+		dma_sync_desc_dev(dev, td);
+		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))) {
+			dma_sync_desc_dev(dev, td);
+			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;
+
+	netif_trans_update(dev); /* prevent tx timeout */
+	netif_wake_queue(dev);
+
+	return 0;
+}
+
+static netdev_tx_t
+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, unsigned int txqueue)
+{
+	printk(KERN_NOTICE "%s: transmit timed out, resetting\n", dev->name);
+	sgiseeq_reset(dev);
+
+	netif_trans_update(dev); /* 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_validate_addr	= eth_validate_addr,
+};
+
+static int sgiseeq_probe(struct platform_device *pdev)
+{
+	struct sgiseeq_platform_data *pd = dev_get_platdata(&pdev->dev);
+	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);
+	SET_NETDEV_DEV(dev, &pdev->dev);
+	sp = netdev_priv(dev);
+
+	/* Make private data page aligned */
+	sr = dma_alloc_noncoherent(&pdev->dev, sizeof(*sp->srings),
+			&sp->srings_dma, DMA_BIDIRECTIONAL, 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);
+
+	eth_hw_addr_set(dev, pd->mac);
+
+#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_attrs;
+	}
+
+	printk(KERN_INFO "%s: %s %pM\n", dev->name, sgiseeqstr, dev->dev_addr);
+
+	return 0;
+
+err_out_free_attrs:
+	dma_free_noncoherent(&pdev->dev, sizeof(*sp->srings), sp->srings,
+		       sp->srings_dma, DMA_BIDIRECTIONAL);
+err_out_free_dev:
+	free_netdev(dev);
+
+err_out:
+	return err;
+}
+
+static int 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, DMA_BIDIRECTIONAL);
+	free_netdev(dev);
+
+	return 0;
+}
+
+static struct platform_driver sgiseeq_driver = {
+	.probe	= sgiseeq_probe,
+	.remove	= sgiseeq_remove,
+	.driver = {
+		.name	= "sgiseeq",
+	}
+};
+
+module_platform_driver(sgiseeq_driver);
+
+MODULE_DESCRIPTION("SGI Seeq 8003 driver");
+MODULE_AUTHOR("Linux/MIPS Mailing List <linux-mips@linux-mips.org>");
+MODULE_LICENSE("GPL");
+MODULE_ALIAS("platform:sgiseeq");