/*
 * meth.c -- O2 Builtin 10/100 Ethernet driver
 *
 * Copyright (C) 2001 Ilya Volynets
 *
 *	This program is free software; you can redistribute it and/or
 *	modify it under the terms of the GNU General Public License
 *	as published by the Free Software Foundation; either version
 *	2 of the License, or (at your option) any later version.
 */
#include <linux/module.h>
#include <linux/init.h>

#include <linux/sched.h>
#include <linux/kernel.h> /* printk() */
#include <linux/delay.h>
#include <linux/slab.h>
#include <linux/errno.h>  /* error codes */
#include <linux/types.h>  /* size_t */
#include <linux/interrupt.h> /* mark_bh */
#include <linux/pci.h>

#include <linux/in.h>
#include <linux/netdevice.h>   /* struct device, and other headers */
#include <linux/etherdevice.h> /* eth_type_trans */
#include <linux/ip.h>          /* struct iphdr */
#include <linux/tcp.h>         /* struct tcphdr */
#include <linux/skbuff.h>
#include <linux/mii.h> /*MII definitions */

#include <asm/ip32/crime.h>
#include <asm/ip32/mace.h>
#include <asm/ip32/ip32_ints.h>

#include "meth.h"

#include <linux/in6.h>
#include <asm/checksum.h>

#ifndef MFE_DEBUG
#define MFE_DEBUG 0
#endif

#if MFE_DEBUG>=1
#define DPRINTK(str,args...) printk (KERN_DEBUG "meth(%ld): %s: " str, jiffies, __FUNCTION__ , ## args)
#define MFE_RX_DEBUG 2
#else
#define DPRINTK(str,args...)
#define MFE_RX_DEBUG 0
#endif


static const char *version="meth.c: Ilya Volynets (ilya@theIlya.com)";
static const char *meth_str="SGI O2 Fast Ethernet";
MODULE_AUTHOR("Ilya Volynets");
MODULE_DESCRIPTION("SGI O2 Builtin Fast Ethernet driver");

/* This is a load-time options */
/*static int eth = 0;
MODULE_PARM(eth, "i");*/

#define HAVE_TX_TIMEOUT
/* The maximum time waited (in jiffies) before assuming a Tx failed. (400ms) */
#define TX_TIMEOUT (400*HZ/1000)

#ifdef HAVE_TX_TIMEOUT
static int timeout = TX_TIMEOUT;
MODULE_PARM(timeout, "i");
#endif

int meth_eth;


/*
 * This structure is private to each device. It is used to pass
 * packets in and out, so there is place for a packet
 */

typedef struct meth_private {
    struct net_device_stats stats;
	volatile struct meth_regs *regs;
	u64 mode; /* in-memory copy of MAC control register */
	int  phy_addr; /* address of phy, used by mdio_* functions, initialized in mdio_probe*/
	tx_packet *tx_ring;
	dma_addr_t tx_ring_dma;
	int free_space;
	struct sk_buff *tx_skbs[TX_RING_ENTRIES];
	dma_addr_t      tx_skb_dmas[TX_RING_ENTRIES];
	int tx_read,tx_write;
	int tx_count;

	rx_packet *rx_ring[RX_RING_ENTRIES];
	dma_addr_t rx_ring_dmas[RX_RING_ENTRIES];
	int rx_write;

    spinlock_t meth_lock;
} meth_private;

extern struct net_device meth_devs[];
void meth_tx_timeout (struct net_device *dev);
void meth_interrupt(int irq, void *dev_id, struct pt_regs *pregs);
        
/* global, initialized in ip32-setup.c */
char o2meth_eaddr[8]={0,0,0,0,0,0,0,0};

static inline void load_eaddr(struct net_device *dev,
			      volatile struct meth_regs *regs)
{
	int i;
	DPRINTK("Loading MAC Address: %02x:%02x:%02x:%02x:%02x:%02x\n",
		(int)o2meth_eaddr[0]&0xFF,(int)o2meth_eaddr[1]&0xFF,(int)o2meth_eaddr[2]&0xFF,
		(int)o2meth_eaddr[3]&0xFF,(int)o2meth_eaddr[4]&0xFF,(int)o2meth_eaddr[5]&0xFF);
	//memcpy(dev->dev_addr,o2meth_eaddr+2,6);
	for (i=0; i<6; i++)
		dev->dev_addr[i]=o2meth_eaddr[i];
	regs->mac_addr= //dev->dev_addr[0]|(dev->dev_addr[1]<<8)|
					//dev->dev_addr[2]<<16|(dev->dev_addr[3]<<24)|
					//dev->dev_addr[4]<<32|(dev->dev_addr[5]<<40);
	(*(u64*)o2meth_eaddr)>>16;
	DPRINTK("MAC, finally is %0lx\n",regs->mac_addr);
}

/*
 *Waits for BUSY status of mdio bus to clear
 */
#define WAIT_FOR_PHY(___regs, ___rval)			\
	while((___rval=___regs->phy_data)&MDIO_BUSY){	\
		udelay(25);								\
	}
/*read phy register, return value read */
static int mdio_read(meth_private *priv,int phyreg)
{
	volatile meth_regs* regs=priv->regs;
	volatile u32 rval;
	WAIT_FOR_PHY(regs,rval)
	regs->phy_registers=(priv->phy_addr<<5)|(phyreg&0x1f);
	udelay(25);
	regs->phy_trans_go=1;
	udelay(25);
	WAIT_FOR_PHY(regs,rval)
	return rval&MDIO_DATA_MASK;
}

/*write phy register */
static void mdio_write(meth_private* priv,int pfyreg,int val)
{
	volatile meth_regs* regs=priv->regs;
	int rval;
///	DPRINTK("Trying to write value %i to reguster %i\n",val, pfyreg);
	spin_lock_irq(&priv->meth_lock);
	WAIT_FOR_PHY(regs,rval)
	regs->phy_registers=(priv->phy_addr<<5)|(pfyreg&0x1f);
	regs->phy_data=val;
	udelay(25);
	WAIT_FOR_PHY(regs,rval)
	spin_unlock_irq(&priv->meth_lock);
}

/* Modify phy register using given mask and value */
static void mdio_update(meth_private* priv,int phyreg, int val, int mask)
{
	int rval;
	DPRINTK("RMW value %i to PHY register %i with mask %i\n",val,phyreg,mask);
	rval=mdio_read(priv,phyreg);
	rval=(rval&~mask)|(val&mask);
	mdio_write(priv,phyreg,rval);
}

/* handle errata data on MDIO bus */
//static void mdio_errata(meth_private *priv)
//{
	/* Hmmm... what the hell is phyerrata? does it come from sys init parameters in IRIX */
//}
static int mdio_probe(meth_private *priv)
{
	int i, p2, p3;
	DPRINTK("Detecting PHY kind\n");
	/* check if phy is detected already */
	if(priv->phy_addr>=0&&priv->phy_addr<32)
		return 0;
	spin_lock_irq(&priv->meth_lock);
	for (i=0;i<32;++i){
		priv->phy_addr=(char)i;
		p2=mdio_read(priv,2);
#ifdef MFE_DEBUG
		p3=mdio_read(priv,3);
		switch ((p2<<12)|(p3>>4)){
			case PHY_QS6612X:
				DPRINTK("PHY is QS6612X\n");
				break;
			case PHY_ICS1889:
				DPRINTK("PHY is ICS1889\n");
				break;
			case PHY_ICS1890:
				DPRINTK("PHY is ICS1890\n");
				break;
			case PHY_DP83840:
				DPRINTK("PHY is DP83840\n");
				break;
		}
#endif
		if(p2!=0xffff&&p2!=0x0000){
			DPRINTK("PHY code: %x\n",(p2<<12)|(p3>>4));
			break;
		}
	}
	spin_unlock_irq(&priv->meth_lock);
	if(priv->phy_addr<32) {
		return 0;
	}
	DPRINTK("Oopsie! PHY is not known!\n");
	priv->phy_addr=-1;
	return -ENODEV;
}

static void meth_check_link(struct net_device *dev)
{
	struct meth_private *priv = (struct meth_private *) dev->priv;
	int mii_partner = mdio_read(priv, 5);
	int mii_advertising = mdio_read(priv, 4);
	int negotiated = mii_advertising & mii_partner;
	int duplex, speed;

	if (mii_partner == 0xffff)
		return;

	duplex = ((negotiated & 0x0100) || (negotiated & 0x01C0) == 0x0040)?METH_PHY_FDX:0;
	speed = (negotiated & 0x0380)?METH_100MBIT:0;

	if ((priv->mode & METH_PHY_FDX) ^ duplex)
	{
		DPRINTK("Setting %s-duplex\n", duplex ? "full" : "half");
		if (duplex)
			priv->mode |= METH_PHY_FDX;
		else
			priv->mode &= ~METH_PHY_FDX;
		priv->regs->mac_ctrl = priv->mode;
	}

	if ((priv->mode & METH_100MBIT) ^ speed)
	{
		DPRINTK("Setting %dMbs mode\n", speed ? 100 : 10);
		if (duplex)
			priv->mode |= METH_100MBIT;
		else
			priv->mode &= ~METH_100MBIT;
		priv->regs->mac_ctrl = priv->mode;
	}
}


static int meth_init_tx_ring(meth_private *priv)
{
	/* Init TX ring */
	DPRINTK("Initializing TX ring\n");
	priv->tx_ring = (tx_packet *) pci_alloc_consistent(NULL,TX_RING_BUFFER_SIZE,&(priv->tx_ring_dma));
	if(!priv->tx_ring)
		return -ENOMEM;
	memset(priv->tx_ring, 0, TX_RING_BUFFER_SIZE);
	priv->tx_count = priv->tx_read = priv->tx_write = 0;
	priv->regs->tx_ring_base = priv->tx_ring_dma;
	priv->free_space = TX_RING_ENTRIES;
	/* Now init skb save area */
	memset(priv->tx_skbs,0,sizeof(priv->tx_skbs));
	memset(priv->tx_skb_dmas,0,sizeof(priv->tx_skb_dmas));
	DPRINTK("Done with TX ring init\n");
	return 0;
}

static int meth_init_rx_ring(meth_private *priv)
{
	int i;
	DPRINTK("Initializing RX ring\n");
	for(i=0;i<RX_RING_ENTRIES;i++){
		DPRINTK("\t1:\t%i\t",i);
		/*if(!(priv->rx_ring[i]=get_free_page(GFP_KERNEL)))
			return -ENOMEM;
		DPRINTK("\t2:\t%i\n",i);*/
		priv->rx_ring[i]=(rx_packet*)pci_alloc_consistent(NULL,METH_RX_BUFF_SIZE,&(priv->rx_ring_dmas[i]));
		/* I'll need to re-sync it after each RX */
		DPRINTK("\t%p\n",priv->rx_ring[i]);
		priv->regs->rx_fifo=priv->rx_ring_dmas[i];
	}
	priv->rx_write = 0;
	DPRINTK("Done with RX ring\n");
	return 0;
}
static void meth_free_tx_ring(meth_private *priv)
{
	int i;

	/* Remove any pending skb */
	for (i = 0; i < TX_RING_ENTRIES; i++) {
	  if (priv->tx_skbs[i])
		dev_kfree_skb(priv->tx_skbs[i]);
		priv->tx_skbs[i] = NULL;
	}
	pci_free_consistent(NULL,
			    TX_RING_BUFFER_SIZE,
			    priv->tx_ring,
			    priv->tx_ring_dma);
}
static void meth_free_rx_ring(meth_private *priv)
{
	int i;

	for(i=0;i<RX_RING_ENTRIES;i++)
		pci_free_consistent(NULL,
				    METH_RX_BUFF_SIZE,
				    priv->rx_ring[i],
				    priv->rx_ring_dmas[i]);
}

int meth_reset(struct net_device *dev)
{
	struct meth_private *priv = (struct meth_private *) dev->priv;

	/* Reset card */
	priv->regs->mac_ctrl = SGI_MAC_RESET;
	priv->regs->mac_ctrl = 0;
	udelay(25);
	DPRINTK("MAC control after reset: %016lx\n", priv->regs->mac_ctrl);

	/* Load ethernet address */
	load_eaddr(dev, priv->regs);
	/* Should load some "errata", but later */
	
	/* Check for device */
	if(mdio_probe(priv) < 0) {
		DPRINTK("Unable to find PHY\n");
		return -ENODEV;
	}

	/* Initial mode -- 10|Half-duplex|Accept normal packets */
	priv->mode=METH_ACCEPT_MCAST|METH_DEFAULT_IPG;
	if(dev->flags | IFF_PROMISC)
		priv->mode |= METH_PROMISC;
	priv->regs->mac_ctrl = priv->mode;

	/* Autonegociate speed and duplex mode */
	meth_check_link(dev);

	/* Now set dma control, but don't enable DMA, yet */
	priv->regs->dma_ctrl= (4 << METH_RX_OFFSET_SHIFT) |
		              (RX_RING_ENTRIES << METH_RX_DEPTH_SHIFT);

	return(0);
}

/*============End Helper Routines=====================*/

/*
 * Open and close
 */

int meth_open(struct net_device *dev)
{
	meth_private *priv=dev->priv;
	volatile meth_regs *regs=priv->regs;

	MOD_INC_USE_COUNT;

	/* Start DMA */
	regs->dma_ctrl|=
	        METH_DMA_TX_EN|/*METH_DMA_TX_INT_EN|*/
		METH_DMA_RX_EN|METH_DMA_RX_INT_EN;

	if(request_irq(dev->irq,meth_interrupt,SA_SHIRQ,meth_str,dev)){
		printk(KERN_ERR "%s: Can't get irq %d\n", dev->name, dev->irq);
		return -EAGAIN;
	}
	netif_start_queue(dev);
	DPRINTK("Opened... DMA control=0x%08lx\n", regs->dma_ctrl);
	return 0;
}

int meth_release(struct net_device *dev)
{
    netif_stop_queue(dev); /* can't transmit any more */
	/* shut down dma */
	((meth_private*)(dev->priv))->regs->dma_ctrl&=
		~(METH_DMA_TX_EN|METH_DMA_TX_INT_EN|
		METH_DMA_RX_EN|METH_DMA_RX_INT_EN);
	free_irq(dev->irq, dev);
    MOD_DEC_USE_COUNT;
    return 0;
}

/*
 * Configuration changes (passed on by ifconfig)
 */
int meth_config(struct net_device *dev, struct ifmap *map)
{
    if (dev->flags & IFF_UP) /* can't act on a running interface */
        return -EBUSY;

    /* Don't allow changing the I/O address */
    if (map->base_addr != dev->base_addr) {
        printk(KERN_WARNING "meth: Can't change I/O address\n");
        return -EOPNOTSUPP;
    }

    /* Allow changing the IRQ */
    if (map->irq != dev->irq) {
        printk(KERN_WARNING "meth: Can't change IRQ\n");
        return -EOPNOTSUPP;
    }
	DPRINTK("Configured\n");

    /* ignore other fields */
    return 0;
}

/*
 * Receive a packet: retrieve, encapsulate and pass over to upper levels
 */
void meth_rx(struct net_device* dev)
{
    struct sk_buff *skb;
    struct meth_private *priv = (struct meth_private *) dev->priv;
	rx_packet *rxb;
	DPRINTK("RX...\n");
	// TEMP	while((rxb=priv->rx_ring[priv->rx_write])->status.raw&0x8000000000000000){
	while((rxb=priv->rx_ring[priv->rx_write])->status.raw&0x8000000000000000){
	        int len=rxb->status.parsed.rx_len - 4; /* omit CRC */
		DPRINTK("(%i)\n",priv->rx_write);
		/* length sanity check */
		if(len < 60 || len > 1518) {
		  printk(KERN_DEBUG "%s: bogus packet size: %d, status=%#2x.\n",
			 dev->name, priv->rx_write, rxb->status.raw);
		  priv->stats.rx_errors++;
		  priv->stats.rx_length_errors++;
		}
		if(!(rxb->status.raw&METH_RX_STATUS_ERRORS)){
			skb=alloc_skb(len+2,GFP_ATOMIC);/* Should be atomic -- we are in interrupt */
			if(!skb){
				/* Ouch! No memory! Drop packet on the floor */
				DPRINTK("!!!>>>Ouch! Not enough Memory for RX buffer!\n");
				priv->stats.rx_dropped++;
			} else {
				skb_reserve(skb, 2); /* align IP on 16B boundary */  
    			memcpy(skb_put(skb, len), rxb->buf, len);
			    /* Write metadata, and then pass to the receive level */
			    skb->dev = dev;
			    skb->protocol = eth_type_trans(skb, dev);
				//skb->ip_summed = CHECKSUM_UNNECESSARY; /* don't check it */
			   
				DPRINTK("passing packet\n");
				DPRINTK("len = %d rxb->status = %x\n",
					len, rxb->status.raw);
				netif_rx(skb);
				dev->last_rx = jiffies;
				priv->stats.rx_packets++;
				priv->stats.rx_bytes+=len;
				DPRINTK("There we go... Whew...\n");
			}
		}
		priv->regs->rx_fifo=priv->rx_ring_dmas[priv->rx_write];
		rxb->status.raw=0;		
		priv->rx_write=(priv->rx_write+1)&(RX_RING_ENTRIES-1);
	}
}

static int meth_tx_full(struct net_device *dev)
{
	struct meth_private *priv = (struct meth_private *) dev->priv;

	return(priv->tx_count >= TX_RING_ENTRIES-1);
}

void meth_tx_cleanup(struct net_device* dev, int rptr)
{
	meth_private *priv=dev->priv;
	tx_packet* status;
	struct sk_buff *skb;

	spin_lock(&priv->meth_lock);

	/* Stop DMA */
	priv->regs->dma_ctrl &= ~(METH_DMA_TX_INT_EN);

	while(priv->tx_read != rptr){
		skb = priv->tx_skbs[priv->tx_read];
		status = &priv->tx_ring[priv->tx_read];
		if(!status->header.res.sent)
			break;
		if(status->header.raw & METH_TX_STATUS_DONE) {
			priv->stats.tx_packets++;
			priv->stats.tx_bytes += skb->len;
		}
		dev_kfree_skb_irq(skb);
		priv->tx_skbs[priv->tx_read] = NULL;
		status->header.raw = 0;
		priv->tx_read = (priv->tx_read+1)&(TX_RING_ENTRIES-1);
		priv->tx_count --;
	}

	/* wake up queue if it was stopped */
	if (netif_queue_stopped(dev) && ! meth_tx_full(dev)) {
		netif_wake_queue(dev);
	}

	spin_unlock(priv->meth_lock);
}

/*
 * The typical interrupt entry point
 */
void meth_interrupt(int irq, void *dev_id, struct pt_regs *pregs)
{
	struct meth_private *priv;
	union {
		u32	reg; /*Whole status register */
		struct {
			u32			:	2,
				rx_seq	:	5,
				tx_read	:	9,
				
				rx_read	:	8,
				int_mask:	8;
		} parsed;
	} status;
	/*
	 * As usual, check the "device" pointer for shared handlers.
	 * Then assign "struct device *dev"
	 */
	struct net_device *dev = (struct net_device *)dev_id;
	/* ... and check with hw if it's really ours */

	if (!dev /*paranoid*/ ) return;

	/* Lock the device */
	priv = (struct meth_private *) dev->priv;

	status.reg = priv->regs->int_flags;
    
	DPRINTK("Interrupt, status %08x...\n",status.reg);
	if (status.parsed.int_mask & METH_INT_RX_THRESHOLD) {
		/* send it to meth_rx for handling */
		meth_rx(dev);
	}

	if (status.parsed.int_mask & (METH_INT_TX_EMPTY|METH_INT_TX_PKT)) {
		/* a transmission is over: free the skb */
		meth_tx_cleanup(dev, status.parsed.tx_read);
	}
	/* check for errors too... */
	if (status.parsed.int_mask & (METH_INT_TX_LINK_FAIL))
		printk(KERN_WARNING "meth: link failure\n");
	if (status.parsed.int_mask & (METH_INT_MEM_ERROR))
		printk(KERN_WARNING "meth: memory error\n");
	if (status.parsed.int_mask & (METH_INT_TX_ABORT))
		printk(KERN_WARNING "meth: aborted\n");
	DPRINTK("Interrupt handling done...\n");
	
	priv->regs->int_flags=status.reg&0xff; /* clear interrupts */
}

/*
 * Transmits packets that fit into TX descriptor (are <=120B)
 */
static void meth_tx_short_prepare(meth_private* priv, struct sk_buff* skb)
{
	tx_packet *desc=&priv->tx_ring[priv->tx_write];
	int len = (skb->len<ETH_ZLEN)?ETH_ZLEN:skb->len;

	DPRINTK("preparing short packet\n");
	/* maybe I should set whole thing to 0 first... */
	memcpy(desc->data.dt+(120-len),skb->data,skb->len);
	if(skb->len < len)
		memset(desc->data.dt+120-len+skb->len,0,len-skb->len);
	desc->header.raw=METH_TX_CMD_INT_EN|(len-1)|((128-len)<<16);
	DPRINTK("desc=%016lx\n",desc->header.raw);
}
#define TX_CATBUF1 BIT(25)
static void meth_tx_1page_prepare(meth_private* priv, struct sk_buff* skb)
{
	tx_packet *desc=&priv->tx_ring[priv->tx_write];
	void *buffer_data = (void *)(((u64)skb->data + 7ULL) & (~7ULL));
	int unaligned_len = (int)((u64)buffer_data - (u64)skb->data);
	int buffer_len = skb->len - unaligned_len;
	dma_addr_t catbuf;

	DPRINTK("preparing 1 page...\n");
	DPRINTK("length=%d data=%p\n", skb->len, skb->data);
	DPRINTK("unaligned_len=%d\n", unaligned_len);
	DPRINTK("buffer_data=%p buffer_len=%d\n",
	       buffer_data,
	       buffer_len);

	desc->header.raw=METH_TX_CMD_INT_EN|TX_CATBUF1|(skb->len-1);

	/* unaligned part */
	if(unaligned_len){
		memcpy(desc->data.dt+(120-unaligned_len),
		       skb->data, unaligned_len);
		desc->header.raw |= (128-unaligned_len) << 16;
	}

	/* first page */
	catbuf = pci_map_single(NULL,
				buffer_data,
				buffer_len,
				PCI_DMA_TODEVICE);
	DPRINTK("catbuf=%x\n", catbuf);
	desc->data.cat_buf[0].form.start_addr = catbuf >> 3;
	desc->data.cat_buf[0].form.len = buffer_len-1;
	DPRINTK("desc=%016lx\n",desc->header.raw);
	DPRINTK("cat_buf[0].raw=%016lx\n",desc->data.cat_buf[0].raw);
}
#define TX_CATBUF2 BIT(26)
static void meth_tx_2page_prepare(meth_private* priv, struct sk_buff* skb)
{
	tx_packet *desc=&priv->tx_ring[priv->tx_write];
	void *buffer1_data = (void *)(((u64)skb->data + 7ULL) & (~7ULL));
	void *buffer2_data = (void *)PAGE_ALIGN((u64)skb->data);
	int unaligned_len = (int)((u64)buffer1_data - (u64)skb->data);
	int buffer1_len = (int)((u64)buffer2_data - (u64)buffer1_data);
	int buffer2_len = skb->len - buffer1_len - unaligned_len;
	dma_addr_t catbuf1, catbuf2;

	DPRINTK("preparing 2 pages... \n");
	DPRINTK("length=%d data=%p\n", skb->len, skb->data);
	DPRINTK("unaligned_len=%d\n", unaligned_len);
	DPRINTK("buffer1_data=%p buffer1_len=%d\n",
	       buffer1_data,
	       buffer1_len);
	DPRINTK("buffer2_data=%p buffer2_len=%d\n",
	       buffer2_data,
	       buffer2_len);

	desc->header.raw=METH_TX_CMD_INT_EN|TX_CATBUF1|TX_CATBUF2|(skb->len-1);
	/* unaligned part */
	if(unaligned_len){
		memcpy(desc->data.dt+(120-unaligned_len),
		       skb->data, unaligned_len);
		desc->header.raw |= (128-unaligned_len) << 16;
	}

	/* first page */
	catbuf1 = pci_map_single(NULL,
				 buffer1_data,
				 buffer1_len,
				 PCI_DMA_TODEVICE);
	DPRINTK("catbuf1=%x\n", catbuf1);
	desc->data.cat_buf[0].form.start_addr = catbuf1 >> 3;
	desc->data.cat_buf[0].form.len = buffer1_len-1;
	/* second page */
	catbuf2 = pci_map_single(NULL,
				 buffer2_data,
				 buffer2_len,
				 PCI_DMA_TODEVICE);
	DPRINTK("catbuf2=%x\n", catbuf2);
	desc->data.cat_buf[1].form.start_addr = catbuf2 >> 3;
	desc->data.cat_buf[1].form.len = buffer2_len-1;
	DPRINTK("desc=%016lx\n",desc->header.raw);
	DPRINTK("cat_buf[0].raw=%016lx\n",desc->data.cat_buf[0].raw);
	DPRINTK("cat_buf[1].raw=%016lx\n",desc->data.cat_buf[1].raw);
}


void meth_add_to_tx_ring(meth_private *priv, struct sk_buff* skb)
{
	DPRINTK("Transmitting data...\n");
	if(skb->len <= 120) {
		/* Whole packet fits into descriptor */
		meth_tx_short_prepare(priv,skb);
	} else if(PAGE_ALIGN((u64)skb->data) !=
		  PAGE_ALIGN((u64)skb->data+skb->len-1)) {
		/* Packet crosses page boundary */
		meth_tx_2page_prepare(priv,skb);
	} else {
		/* Packet is in one page */
		meth_tx_1page_prepare(priv,skb);
	}

	/* Remember the skb, so we can free it at interrupt time */
	priv->tx_skbs[priv->tx_write] = skb;
	priv->tx_write = (priv->tx_write+1) & (TX_RING_ENTRIES-1);
	priv->regs->tx_info.wptr = priv->tx_write;
	priv->tx_count ++;
	/* Enable DMA transfer */
	priv->regs->dma_ctrl |= METH_DMA_TX_INT_EN;
}

/*
 * Transmit a packet (called by the kernel)
 */
int meth_tx(struct sk_buff *skb, struct net_device *dev)
{
	struct meth_private *priv = (struct meth_private *) dev->priv;

	spin_lock_irq(&priv->meth_lock);

	meth_add_to_tx_ring(priv, skb);
	dev->trans_start = jiffies; /* save the timestamp */

	/* If TX ring is full, tell the upper layer to stop sending packets */
	if (meth_tx_full(dev)) {
	        DPRINTK("TX full: stopping\n");
		netif_stop_queue(dev);
	}

	spin_unlock_irq(&priv->meth_lock);

	return 0;
}

/*
 * Deal with a transmit timeout.
 */

void meth_tx_timeout (struct net_device *dev)
{
	struct meth_private *priv = (struct meth_private *) dev->priv;
	
	printk(KERN_WARNING "%s: transmit timed out\n", dev->name);

	/* Protect against concurrent rx interrupts */
	spin_lock_irq(&priv->meth_lock);

	/* Try to reset the adaptor. */
	meth_reset(dev);

	priv->stats.tx_errors++;

	/* Clear all rings */
	meth_free_tx_ring(priv);
	meth_free_rx_ring(priv);
	meth_init_tx_ring(priv);
	meth_init_rx_ring(priv);

	/* Restart dma */
	priv->regs->dma_ctrl|=METH_DMA_TX_EN|METH_DMA_RX_EN|METH_DMA_RX_INT_EN;

	/* Enable interrupt */
	spin_unlock_irq(&priv->meth_lock);

	dev->trans_start = jiffies;
	netif_wake_queue(dev);

	return;
}

/*
 * Ioctl commands 
 */
int meth_ioctl(struct net_device *dev, struct ifreq *rq, int cmd)
{
 
    DPRINTK("ioctl\n");
    return 0;
}

/*
 * Return statistics to the caller
 */
struct net_device_stats *meth_stats(struct net_device *dev)
{
    struct meth_private *priv = (struct meth_private *) dev->priv;
    return &priv->stats;
}

/*
 * The init function (sometimes called probe).
 * It is invoked by register_netdev()
 */
int meth_init(struct net_device *dev)
{
	meth_private *priv;
	int ret;
	/* 
	 * Then, assign other fields in dev, using ether_setup() and some
	 * hand assignments
	 */
	ether_setup(dev); /* assign some of the fields */

	dev->open            = meth_open;
	dev->stop            = meth_release;
	dev->set_config      = meth_config;
	dev->hard_start_xmit = meth_tx;
	dev->do_ioctl        = meth_ioctl;
	dev->get_stats       = meth_stats;
#ifdef HAVE_TX_TIMEOUT
	dev->tx_timeout      = meth_tx_timeout;
	dev->watchdog_timeo  = timeout;
#endif
	dev->irq		 = MACE_ETHERNET_IRQ;
	SET_MODULE_OWNER(dev);

	/*
	 * Then, allocate the priv field. This encloses the statistics
	 * and a few private fields.
	 */
	priv = kmalloc(sizeof(struct meth_private), GFP_KERNEL);
	if (priv == NULL)
		return -ENOMEM;
	dev->priv=priv;
	memset(priv, 0, sizeof(struct meth_private));
	spin_lock_init(&((struct meth_private *) dev->priv)->meth_lock);
	/*
	 * Make the usual checks: check_region(), probe irq, ...  -ENODEV
	 * should be returned if no device found.  No resource should be
	 * grabbed: this is done on open(). 
	 */
	priv->regs=(meth_regs*)SGI_MFE;
	dev->base_addr=SGI_MFE;
	priv->phy_addr = -1; /* No phy is known yet... */

	/* Initialize the hardware */
	if((ret=meth_reset(dev)) < 0)
	        return ret;

	/* Allocate the ring buffers */
	if((ret=meth_init_tx_ring(priv))<0||(ret=meth_init_rx_ring(priv))<0){
		meth_free_tx_ring(priv);
		meth_free_rx_ring(priv);
		return ret;
	}

	printk("SGI O2 Fast Ethernet rev. %ld\n", priv->regs->mac_ctrl >> 29);

    return 0;
}

/*
 * The devices
 */

struct net_device meth_devs[1] = {
    { init: meth_init, }  /* init, nothing more */
};

/*
 * Finally, the module stuff
 */

int meth_init_module(void)
{
	int result, device_present = 0;

	strcpy(meth_devs[0].name, "eth%d");

	if ( (result = register_netdev(meth_devs)) )
		printk("meth: error %i registering device \"%s\"\n",
		       result, meth_devs->name);
	else device_present++;
#ifndef METH_DEBUG
	EXPORT_NO_SYMBOLS;
#endif
	
	return device_present ? 0 : -ENODEV;
}

void meth_cleanup(void)
{
    kfree(meth_devs->priv);
    unregister_netdev(meth_devs);
    return;
}

module_init(meth_init_module);
module_exit(meth_cleanup);
