kbuild: document howto build external modules using several directories

[linux-2.6/verdex.git] / drivers / net / gianfar.c

/*
 * drivers/net/gianfar.c
 *
 * Gianfar Ethernet Driver
 * This driver is designed for the non-CPM ethernet controllers
 * on the 85xx and 83xx family of integrated processors
 * Based on 8260_io/fcc_enet.c
 *
 * Author: Andy Fleming
 * Maintainer: Kumar Gala
 *
 * Copyright (c) 2002-2004 Freescale Semiconductor, Inc.
 *
 * 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.
 *
 *  Gianfar:  AKA Lambda Draconis, "Dragon"
 *  RA 11 31 24.2
 *  Dec +69 19 52
 *  V 3.84
 *  B-V +1.62
 *
 *  Theory of operation
 *
 *  The driver is initialized through platform_device.  Structures which
 *  define the configuration needed by the board are defined in a
 *  board structure in arch/ppc/platforms (though I do not
 *  discount the possibility that other architectures could one
 *  day be supported.
 *
 *  The Gianfar Ethernet Controller uses a ring of buffer
 *  descriptors.  The beginning is indicated by a register
 *  pointing to the physical address of the start of the ring.
 *  The end is determined by a "wrap" bit being set in the
 *  last descriptor of the ring.
 *
 *  When a packet is received, the RXF bit in the
 *  IEVENT register is set, triggering an interrupt when the
 *  corresponding bit in the IMASK register is also set (if
 *  interrupt coalescing is active, then the interrupt may not
 *  happen immediately, but will wait until either a set number
 *  of frames or amount of time have passed).  In NAPI, the
 *  interrupt handler will signal there is work to be done, and
 *  exit.  Without NAPI, the packet(s) will be handled
 *  immediately.  Both methods will start at the last known empty
 *  descriptor, and process every subsequent descriptor until there
 *  are none left with data (NAPI will stop after a set number of
 *  packets to give time to other tasks, but will eventually
 *  process all the packets).  The data arrives inside a
 *  pre-allocated skb, and so after the skb is passed up to the
 *  stack, a new skb must be allocated, and the address field in
 *  the buffer descriptor must be updated to indicate this new
 *  skb.
 *
 *  When the kernel requests that a packet be transmitted, the
 *  driver starts where it left off last time, and points the
 *  descriptor at the buffer which was passed in.  The driver
 *  then informs the DMA engine that there are packets ready to
 *  be transmitted.  Once the controller is finished transmitting
 *  the packet, an interrupt may be triggered (under the same
 *  conditions as for reception, but depending on the TXF bit).
 *  The driver then cleans up the buffer.
 */

#include <linux/config.h>
#include <linux/kernel.h>
#include <linux/sched.h>
#include <linux/string.h>
#include <linux/errno.h>
#include <linux/unistd.h>
#include <linux/slab.h>
#include <linux/interrupt.h>
#include <linux/init.h>
#include <linux/delay.h>
#include <linux/netdevice.h>
#include <linux/etherdevice.h>
#include <linux/skbuff.h>
#include <linux/if_vlan.h>
#include <linux/spinlock.h>
#include <linux/mm.h>
#include <linux/platform_device.h>
#include <linux/ip.h>
#include <linux/tcp.h>
#include <linux/udp.h>

#include <asm/io.h>
#include <asm/irq.h>
#include <asm/uaccess.h>
#include <linux/module.h>
#include <linux/dma-mapping.h>
#include <linux/crc32.h>
#include <linux/mii.h>
#include <linux/phy.h>

#include "gianfar.h"
#include "gianfar_mii.h"

#define TX_TIMEOUT      (1*HZ)
#define SKB_ALLOC_TIMEOUT 1000000
#undef BRIEF_GFAR_ERRORS
#undef VERBOSE_GFAR_ERRORS

#ifdef CONFIG_GFAR_NAPI
#define RECEIVE(x) netif_receive_skb(x)
#else
#define RECEIVE(x) netif_rx(x)
#endif

const char gfar_driver_name[] = "Gianfar Ethernet";
const char gfar_driver_version[] = "1.3";

static int gfar_enet_open(struct net_device *dev);
static int gfar_start_xmit(struct sk_buff *skb, struct net_device *dev);
static void gfar_timeout(struct net_device *dev);
static int gfar_close(struct net_device *dev);
struct sk_buff *gfar_new_skb(struct net_device *dev, struct rxbd8 *bdp);
static struct net_device_stats *gfar_get_stats(struct net_device *dev);
static int gfar_set_mac_address(struct net_device *dev);
static int gfar_change_mtu(struct net_device *dev, int new_mtu);
static irqreturn_t gfar_error(int irq, void *dev_id, struct pt_regs *regs);
static irqreturn_t gfar_transmit(int irq, void *dev_id, struct pt_regs *regs);
static irqreturn_t gfar_interrupt(int irq, void *dev_id, struct pt_regs *regs);
static void adjust_link(struct net_device *dev);
static void init_registers(struct net_device *dev);
static int init_phy(struct net_device *dev);
static int gfar_probe(struct platform_device *pdev);
static int gfar_remove(struct platform_device *pdev);
static void free_skb_resources(struct gfar_private *priv);
static void gfar_set_multi(struct net_device *dev);
static void gfar_set_hash_for_addr(struct net_device *dev, u8 *addr);
#ifdef CONFIG_GFAR_NAPI
static int gfar_poll(struct net_device *dev, int *budget);
#endif
int gfar_clean_rx_ring(struct net_device *dev, int rx_work_limit);
static int gfar_process_frame(struct net_device *dev, struct sk_buff *skb, int length);
static void gfar_vlan_rx_register(struct net_device *netdev,
                                struct vlan_group *grp);
static void gfar_vlan_rx_kill_vid(struct net_device *netdev, uint16_t vid);
void gfar_halt(struct net_device *dev);
void gfar_start(struct net_device *dev);
static void gfar_clear_exact_match(struct net_device *dev);
static void gfar_set_mac_for_addr(struct net_device *dev, int num, u8 *addr);

extern struct ethtool_ops gfar_ethtool_ops;

MODULE_AUTHOR("Freescale Semiconductor, Inc");
MODULE_DESCRIPTION("Gianfar Ethernet Driver");
MODULE_LICENSE("GPL");

/* Returns 1 if incoming frames use an FCB */
static inline int gfar_uses_fcb(struct gfar_private *priv)
{
        return (priv->vlan_enable || priv->rx_csum_enable);
}

/* Set up the ethernet device structure, private data,
 * and anything else we need before we start */
static int gfar_probe(struct platform_device *pdev)
{
        u32 tempval;
        struct net_device *dev = NULL;
        struct gfar_private *priv = NULL;
        struct gianfar_platform_data *einfo;
        struct resource *r;
        int idx;
        int err = 0;

        einfo = (struct gianfar_platform_data *) pdev->dev.platform_data;

        if (NULL == einfo) {
                printk(KERN_ERR "gfar %d: Missing additional data!\n",
                       pdev->id);

                return -ENODEV;
        }

        /* Create an ethernet device instance */
        dev = alloc_etherdev(sizeof (*priv));

        if (NULL == dev)
                return -ENOMEM;

        priv = netdev_priv(dev);

        /* Set the info in the priv to the current info */
        priv->einfo = einfo;

        /* fill out IRQ fields */
        if (einfo->device_flags & FSL_GIANFAR_DEV_HAS_MULTI_INTR) {
                priv->interruptTransmit = platform_get_irq_byname(pdev, "tx");
                priv->interruptReceive = platform_get_irq_byname(pdev, "rx");
                priv->interruptError = platform_get_irq_byname(pdev, "error");
        } else {
                priv->interruptTransmit = platform_get_irq(pdev, 0);
        }

        /* get a pointer to the register memory */
        r = platform_get_resource(pdev, IORESOURCE_MEM, 0);
        priv->regs = (struct gfar *)
                ioremap(r->start, sizeof (struct gfar));

        if (NULL == priv->regs) {
                err = -ENOMEM;
                goto regs_fail;
        }

        spin_lock_init(&priv->lock);

        platform_set_drvdata(pdev, dev);

        /* Stop the DMA engine now, in case it was running before */
        /* (The firmware could have used it, and left it running). */
        /* To do this, we write Graceful Receive Stop and Graceful */
        /* Transmit Stop, and then wait until the corresponding bits */
        /* in IEVENT indicate the stops have completed. */
        tempval = gfar_read(&priv->regs->dmactrl);
        tempval &= ~(DMACTRL_GRS | DMACTRL_GTS);
        gfar_write(&priv->regs->dmactrl, tempval);

        tempval = gfar_read(&priv->regs->dmactrl);
        tempval |= (DMACTRL_GRS | DMACTRL_GTS);
        gfar_write(&priv->regs->dmactrl, tempval);

        while (!(gfar_read(&priv->regs->ievent) & (IEVENT_GRSC | IEVENT_GTSC)))
                cpu_relax();

        /* Reset MAC layer */
        gfar_write(&priv->regs->maccfg1, MACCFG1_SOFT_RESET);

        tempval = (MACCFG1_TX_FLOW | MACCFG1_RX_FLOW);
        gfar_write(&priv->regs->maccfg1, tempval);

        /* Initialize MACCFG2. */
        gfar_write(&priv->regs->maccfg2, MACCFG2_INIT_SETTINGS);

        /* Initialize ECNTRL */
        gfar_write(&priv->regs->ecntrl, ECNTRL_INIT_SETTINGS);

        /* Copy the station address into the dev structure, */
        memcpy(dev->dev_addr, einfo->mac_addr, MAC_ADDR_LEN);

        /* Set the dev->base_addr to the gfar reg region */
        dev->base_addr = (unsigned long) (priv->regs);

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

        /* Fill in the dev structure */
        dev->open = gfar_enet_open;
        dev->hard_start_xmit = gfar_start_xmit;
        dev->tx_timeout = gfar_timeout;
        dev->watchdog_timeo = TX_TIMEOUT;
#ifdef CONFIG_GFAR_NAPI
        dev->poll = gfar_poll;
        dev->weight = GFAR_DEV_WEIGHT;
#endif
        dev->stop = gfar_close;
        dev->get_stats = gfar_get_stats;
        dev->change_mtu = gfar_change_mtu;
        dev->mtu = 1500;
        dev->set_multicast_list = gfar_set_multi;

        dev->ethtool_ops = &gfar_ethtool_ops;

        if (priv->einfo->device_flags & FSL_GIANFAR_DEV_HAS_CSUM) {
                priv->rx_csum_enable = 1;
                dev->features |= NETIF_F_IP_CSUM;
        } else
                priv->rx_csum_enable = 0;

        priv->vlgrp = NULL;

        if (priv->einfo->device_flags & FSL_GIANFAR_DEV_HAS_VLAN) {
                dev->vlan_rx_register = gfar_vlan_rx_register;
                dev->vlan_rx_kill_vid = gfar_vlan_rx_kill_vid;

                dev->features |= NETIF_F_HW_VLAN_TX | NETIF_F_HW_VLAN_RX;

                priv->vlan_enable = 1;
        }

        if (priv->einfo->device_flags & FSL_GIANFAR_DEV_HAS_EXTENDED_HASH) {
                priv->extended_hash = 1;
                priv->hash_width = 9;

                priv->hash_regs[0] = &priv->regs->igaddr0;
                priv->hash_regs[1] = &priv->regs->igaddr1;
                priv->hash_regs[2] = &priv->regs->igaddr2;
                priv->hash_regs[3] = &priv->regs->igaddr3;
                priv->hash_regs[4] = &priv->regs->igaddr4;
                priv->hash_regs[5] = &priv->regs->igaddr5;
                priv->hash_regs[6] = &priv->regs->igaddr6;
                priv->hash_regs[7] = &priv->regs->igaddr7;
                priv->hash_regs[8] = &priv->regs->gaddr0;
                priv->hash_regs[9] = &priv->regs->gaddr1;
                priv->hash_regs[10] = &priv->regs->gaddr2;
                priv->hash_regs[11] = &priv->regs->gaddr3;
                priv->hash_regs[12] = &priv->regs->gaddr4;
                priv->hash_regs[13] = &priv->regs->gaddr5;
                priv->hash_regs[14] = &priv->regs->gaddr6;
                priv->hash_regs[15] = &priv->regs->gaddr7;

        } else {
                priv->extended_hash = 0;
                priv->hash_width = 8;

                priv->hash_regs[0] = &priv->regs->gaddr0;
                priv->hash_regs[1] = &priv->regs->gaddr1;
                priv->hash_regs[2] = &priv->regs->gaddr2;
                priv->hash_regs[3] = &priv->regs->gaddr3;
                priv->hash_regs[4] = &priv->regs->gaddr4;
                priv->hash_regs[5] = &priv->regs->gaddr5;
                priv->hash_regs[6] = &priv->regs->gaddr6;
                priv->hash_regs[7] = &priv->regs->gaddr7;
        }

        if (priv->einfo->device_flags & FSL_GIANFAR_DEV_HAS_PADDING)
                priv->padding = DEFAULT_PADDING;
        else
                priv->padding = 0;

        if (dev->features & NETIF_F_IP_CSUM)
                dev->hard_header_len += GMAC_FCB_LEN;

        priv->rx_buffer_size = DEFAULT_RX_BUFFER_SIZE;
        priv->tx_ring_size = DEFAULT_TX_RING_SIZE;
        priv->rx_ring_size = DEFAULT_RX_RING_SIZE;

        priv->txcoalescing = DEFAULT_TX_COALESCE;
        priv->txcount = DEFAULT_TXCOUNT;
        priv->txtime = DEFAULT_TXTIME;
        priv->rxcoalescing = DEFAULT_RX_COALESCE;
        priv->rxcount = DEFAULT_RXCOUNT;
        priv->rxtime = DEFAULT_RXTIME;

        /* Enable most messages by default */
        priv->msg_enable = (NETIF_MSG_IFUP << 1 ) - 1;

        err = register_netdev(dev);

        if (err) {
                printk(KERN_ERR "%s: Cannot register net device, aborting.\n",
                                dev->name);
                goto register_fail;
        }

        /* Create all the sysfs files */
        gfar_init_sysfs(dev);

        /* Print out the device info */
        printk(KERN_INFO DEVICE_NAME, dev->name);
        for (idx = 0; idx < 6; idx++)
                printk("%2.2x%c", dev->dev_addr[idx], idx == 5 ? ' ' : ':');
        printk("\n");

        /* Even more device info helps when determining which kernel */
        /* provided which set of benchmarks. */
#ifdef CONFIG_GFAR_NAPI
        printk(KERN_INFO "%s: Running with NAPI enabled\n", dev->name);
#else
        printk(KERN_INFO "%s: Running with NAPI disabled\n", dev->name);
#endif
        printk(KERN_INFO "%s: %d/%d RX/TX BD ring size\n",
               dev->name, priv->rx_ring_size, priv->tx_ring_size);

        return 0;

register_fail:
        iounmap((void *) priv->regs);
regs_fail:
        free_netdev(dev);
        return err;
}

static int gfar_remove(struct platform_device *pdev)
{
        struct net_device *dev = platform_get_drvdata(pdev);
        struct gfar_private *priv = netdev_priv(dev);

        platform_set_drvdata(pdev, NULL);

        iounmap((void *) priv->regs);
        free_netdev(dev);

        return 0;
}


/* Initializes driver's PHY state, and attaches to the PHY.
 * Returns 0 on success.
 */
static int init_phy(struct net_device *dev)
{
        struct gfar_private *priv = netdev_priv(dev);
        uint gigabit_support =
                priv->einfo->device_flags & FSL_GIANFAR_DEV_HAS_GIGABIT ?
                SUPPORTED_1000baseT_Full : 0;
        struct phy_device *phydev;

        priv->oldlink = 0;
        priv->oldspeed = 0;
        priv->oldduplex = -1;

        phydev = phy_connect(dev, priv->einfo->bus_id, &adjust_link, 0);

        if (IS_ERR(phydev)) {
                printk(KERN_ERR "%s: Could not attach to PHY\n", dev->name);
                return PTR_ERR(phydev);
        }

        /* Remove any features not supported by the controller */
        phydev->supported &= (GFAR_SUPPORTED | gigabit_support);
        phydev->advertising = phydev->supported;

        priv->phydev = phydev;

        return 0;
}

static void init_registers(struct net_device *dev)
{
        struct gfar_private *priv = netdev_priv(dev);

        /* Clear IEVENT */
        gfar_write(&priv->regs->ievent, IEVENT_INIT_CLEAR);

        /* Initialize IMASK */
        gfar_write(&priv->regs->imask, IMASK_INIT_CLEAR);

        /* Init hash registers to zero */
        gfar_write(&priv->regs->igaddr0, 0);
        gfar_write(&priv->regs->igaddr1, 0);
        gfar_write(&priv->regs->igaddr2, 0);
        gfar_write(&priv->regs->igaddr3, 0);
        gfar_write(&priv->regs->igaddr4, 0);
        gfar_write(&priv->regs->igaddr5, 0);
        gfar_write(&priv->regs->igaddr6, 0);
        gfar_write(&priv->regs->igaddr7, 0);

        gfar_write(&priv->regs->gaddr0, 0);
        gfar_write(&priv->regs->gaddr1, 0);
        gfar_write(&priv->regs->gaddr2, 0);
        gfar_write(&priv->regs->gaddr3, 0);
        gfar_write(&priv->regs->gaddr4, 0);
        gfar_write(&priv->regs->gaddr5, 0);
        gfar_write(&priv->regs->gaddr6, 0);
        gfar_write(&priv->regs->gaddr7, 0);

        /* Zero out the rmon mib registers if it has them */
        if (priv->einfo->device_flags & FSL_GIANFAR_DEV_HAS_RMON) {
                memset((void *) &(priv->regs->rmon), 0,
                       sizeof (struct rmon_mib));

                /* Mask off the CAM interrupts */
                gfar_write(&priv->regs->rmon.cam1, 0xffffffff);
                gfar_write(&priv->regs->rmon.cam2, 0xffffffff);
        }

        /* Initialize the max receive buffer length */
        gfar_write(&priv->regs->mrblr, priv->rx_buffer_size);

        /* Initialize the Minimum Frame Length Register */
        gfar_write(&priv->regs->minflr, MINFLR_INIT_SETTINGS);

        /* Assign the TBI an address which won't conflict with the PHYs */
        gfar_write(&priv->regs->tbipa, TBIPA_VALUE);
}


/* Halt the receive and transmit queues */
void gfar_halt(struct net_device *dev)
{
        struct gfar_private *priv = netdev_priv(dev);
        struct gfar *regs = priv->regs;
        u32 tempval;

        /* Mask all interrupts */
        gfar_write(&regs->imask, IMASK_INIT_CLEAR);

        /* Clear all interrupts */
        gfar_write(&regs->ievent, IEVENT_INIT_CLEAR);

        /* Stop the DMA, and wait for it to stop */
        tempval = gfar_read(&priv->regs->dmactrl);
        if ((tempval & (DMACTRL_GRS | DMACTRL_GTS))
            != (DMACTRL_GRS | DMACTRL_GTS)) {
                tempval |= (DMACTRL_GRS | DMACTRL_GTS);
                gfar_write(&priv->regs->dmactrl, tempval);

                while (!(gfar_read(&priv->regs->ievent) &
                         (IEVENT_GRSC | IEVENT_GTSC)))
                        cpu_relax();
        }

        /* Disable Rx and Tx */
        tempval = gfar_read(&regs->maccfg1);
        tempval &= ~(MACCFG1_RX_EN | MACCFG1_TX_EN);
        gfar_write(&regs->maccfg1, tempval);
}

void stop_gfar(struct net_device *dev)
{
        struct gfar_private *priv = netdev_priv(dev);
        struct gfar *regs = priv->regs;
        unsigned long flags;

        phy_stop(priv->phydev);

        /* Lock it down */
        spin_lock_irqsave(&priv->lock, flags);

        gfar_halt(dev);

        spin_unlock_irqrestore(&priv->lock, flags);

        /* Free the IRQs */
        if (priv->einfo->device_flags & FSL_GIANFAR_DEV_HAS_MULTI_INTR) {
                free_irq(priv->interruptError, dev);
                free_irq(priv->interruptTransmit, dev);
                free_irq(priv->interruptReceive, dev);
        } else {
                free_irq(priv->interruptTransmit, dev);
        }

        free_skb_resources(priv);

        dma_free_coherent(NULL,
                        sizeof(struct txbd8)*priv->tx_ring_size
                        + sizeof(struct rxbd8)*priv->rx_ring_size,
                        priv->tx_bd_base,
                        gfar_read(&regs->tbase0));
}

/* If there are any tx skbs or rx skbs still around, free them.
 * Then free tx_skbuff and rx_skbuff */
static void free_skb_resources(struct gfar_private *priv)
{
        struct rxbd8 *rxbdp;
        struct txbd8 *txbdp;
        int i;

        /* Go through all the buffer descriptors and free their data buffers */
        txbdp = priv->tx_bd_base;

        for (i = 0; i < priv->tx_ring_size; i++) {

                if (priv->tx_skbuff[i]) {
                        dma_unmap_single(NULL, txbdp->bufPtr,
                                        txbdp->length,
                                        DMA_TO_DEVICE);
                        dev_kfree_skb_any(priv->tx_skbuff[i]);
                        priv->tx_skbuff[i] = NULL;
                }
        }

        kfree(priv->tx_skbuff);

        rxbdp = priv->rx_bd_base;

        /* rx_skbuff is not guaranteed to be allocated, so only
         * free it and its contents if it is allocated */
        if(priv->rx_skbuff != NULL) {
                for (i = 0; i < priv->rx_ring_size; i++) {
                        if (priv->rx_skbuff[i]) {
                                dma_unmap_single(NULL, rxbdp->bufPtr,
                                                priv->rx_buffer_size,
                                                DMA_FROM_DEVICE);

                                dev_kfree_skb_any(priv->rx_skbuff[i]);
                                priv->rx_skbuff[i] = NULL;
                        }

                        rxbdp->status = 0;
                        rxbdp->length = 0;
                        rxbdp->bufPtr = 0;

                        rxbdp++;
                }

                kfree(priv->rx_skbuff);
        }
}

void gfar_start(struct net_device *dev)
{
        struct gfar_private *priv = netdev_priv(dev);
        struct gfar *regs = priv->regs;
        u32 tempval;

        /* Enable Rx and Tx in MACCFG1 */
        tempval = gfar_read(&regs->maccfg1);
        tempval |= (MACCFG1_RX_EN | MACCFG1_TX_EN);
        gfar_write(&regs->maccfg1, tempval);

        /* Initialize DMACTRL to have WWR and WOP */
        tempval = gfar_read(&priv->regs->dmactrl);
        tempval |= DMACTRL_INIT_SETTINGS;
        gfar_write(&priv->regs->dmactrl, tempval);

        /* Clear THLT, so that the DMA starts polling now */
        gfar_write(&regs->tstat, TSTAT_CLEAR_THALT);

        /* Make sure we aren't stopped */
        tempval = gfar_read(&priv->regs->dmactrl);
        tempval &= ~(DMACTRL_GRS | DMACTRL_GTS);
        gfar_write(&priv->regs->dmactrl, tempval);

        /* Unmask the interrupts we look for */
        gfar_write(&regs->imask, IMASK_DEFAULT);
}

/* Bring the controller up and running */
int startup_gfar(struct net_device *dev)
{
        struct txbd8 *txbdp;
        struct rxbd8 *rxbdp;
        dma_addr_t addr;
        unsigned long vaddr;
        int i;
        struct gfar_private *priv = netdev_priv(dev);
        struct gfar *regs = priv->regs;
        int err = 0;
        u32 rctrl = 0;
        u32 attrs = 0;

        gfar_write(&regs->imask, IMASK_INIT_CLEAR);

        /* Allocate memory for the buffer descriptors */
        vaddr = (unsigned long) dma_alloc_coherent(NULL,
                        sizeof (struct txbd8) * priv->tx_ring_size +
                        sizeof (struct rxbd8) * priv->rx_ring_size,
                        &addr, GFP_KERNEL);

        if (vaddr == 0) {
                if (netif_msg_ifup(priv))
                        printk(KERN_ERR "%s: Could not allocate buffer descriptors!\n",
                                        dev->name);
                return -ENOMEM;
        }

        priv->tx_bd_base = (struct txbd8 *) vaddr;

        /* enet DMA only understands physical addresses */
        gfar_write(&regs->tbase0, addr);

        /* Start the rx descriptor ring where the tx ring leaves off */
        addr = addr + sizeof (struct txbd8) * priv->tx_ring_size;
        vaddr = vaddr + sizeof (struct txbd8) * priv->tx_ring_size;
        priv->rx_bd_base = (struct rxbd8 *) vaddr;
        gfar_write(&regs->rbase0, addr);

        /* Setup the skbuff rings */
        priv->tx_skbuff =
            (struct sk_buff **) kmalloc(sizeof (struct sk_buff *) *
                                        priv->tx_ring_size, GFP_KERNEL);

        if (NULL == priv->tx_skbuff) {
                if (netif_msg_ifup(priv))
                        printk(KERN_ERR "%s: Could not allocate tx_skbuff\n",
                                        dev->name);
                err = -ENOMEM;
                goto tx_skb_fail;
        }

        for (i = 0; i < priv->tx_ring_size; i++)
                priv->tx_skbuff[i] = NULL;

        priv->rx_skbuff =
            (struct sk_buff **) kmalloc(sizeof (struct sk_buff *) *
                                        priv->rx_ring_size, GFP_KERNEL);

        if (NULL == priv->rx_skbuff) {
                if (netif_msg_ifup(priv))
                        printk(KERN_ERR "%s: Could not allocate rx_skbuff\n",
                                        dev->name);
                err = -ENOMEM;
                goto rx_skb_fail;
        }

        for (i = 0; i < priv->rx_ring_size; i++)
                priv->rx_skbuff[i] = NULL;

        /* Initialize some variables in our dev structure */
        priv->dirty_tx = priv->cur_tx = priv->tx_bd_base;
        priv->cur_rx = priv->rx_bd_base;
        priv->skb_curtx = priv->skb_dirtytx = 0;
        priv->skb_currx = 0;

        /* Initialize Transmit Descriptor Ring */
        txbdp = priv->tx_bd_base;
        for (i = 0; i < priv->tx_ring_size; i++) {
                txbdp->status = 0;
                txbdp->length = 0;
                txbdp->bufPtr = 0;
                txbdp++;
        }

        /* Set the last descriptor in the ring to indicate wrap */
        txbdp--;
        txbdp->status |= TXBD_WRAP;

        rxbdp = priv->rx_bd_base;
        for (i = 0; i < priv->rx_ring_size; i++) {
                struct sk_buff *skb = NULL;

                rxbdp->status = 0;

                skb = gfar_new_skb(dev, rxbdp);

                priv->rx_skbuff[i] = skb;

                rxbdp++;
        }

        /* Set the last descriptor in the ring to wrap */
        rxbdp--;
        rxbdp->status |= RXBD_WRAP;

        /* If the device has multiple interrupts, register for
         * them.  Otherwise, only register for the one */
        if (priv->einfo->device_flags & FSL_GIANFAR_DEV_HAS_MULTI_INTR) {
                /* Install our interrupt handlers for Error,
                 * Transmit, and Receive */
                if (request_irq(priv->interruptError, gfar_error,
                                0, "enet_error", dev) < 0) {
                        if (netif_msg_intr(priv))
                                printk(KERN_ERR "%s: Can't get IRQ %d\n",
                                        dev->name, priv->interruptError);

                        err = -1;
                        goto err_irq_fail;
                }

                if (request_irq(priv->interruptTransmit, gfar_transmit,
                                0, "enet_tx", dev) < 0) {
                        if (netif_msg_intr(priv))
                                printk(KERN_ERR "%s: Can't get IRQ %d\n",
                                        dev->name, priv->interruptTransmit);

                        err = -1;

                        goto tx_irq_fail;
                }

                if (request_irq(priv->interruptReceive, gfar_receive,
                                0, "enet_rx", dev) < 0) {
                        if (netif_msg_intr(priv))
                                printk(KERN_ERR "%s: Can't get IRQ %d (receive0)\n",
                                                dev->name, priv->interruptReceive);

                        err = -1;
                        goto rx_irq_fail;
                }
        } else {
                if (request_irq(priv->interruptTransmit, gfar_interrupt,
                                0, "gfar_interrupt", dev) < 0) {
                        if (netif_msg_intr(priv))
                                printk(KERN_ERR "%s: Can't get IRQ %d\n",
                                        dev->name, priv->interruptError);

                        err = -1;
                        goto err_irq_fail;
                }
        }

        phy_start(priv->phydev);

        /* Configure the coalescing support */
        if (priv->txcoalescing)
                gfar_write(&regs->txic,
                           mk_ic_value(priv->txcount, priv->txtime));
        else
                gfar_write(&regs->txic, 0);

        if (priv->rxcoalescing)
                gfar_write(&regs->rxic,
                           mk_ic_value(priv->rxcount, priv->rxtime));
        else
                gfar_write(&regs->rxic, 0);

        if (priv->rx_csum_enable)
                rctrl |= RCTRL_CHECKSUMMING;

        if (priv->extended_hash) {
                rctrl |= RCTRL_EXTHASH;

                gfar_clear_exact_match(dev);
                rctrl |= RCTRL_EMEN;
        }

        if (priv->vlan_enable)
                rctrl |= RCTRL_VLAN;

        if (priv->padding) {
                rctrl &= ~RCTRL_PAL_MASK;
                rctrl |= RCTRL_PADDING(priv->padding);
        }

        /* Init rctrl based on our settings */
        gfar_write(&priv->regs->rctrl, rctrl);

        if (dev->features & NETIF_F_IP_CSUM)
                gfar_write(&priv->regs->tctrl, TCTRL_INIT_CSUM);

        /* Set the extraction length and index */
        attrs = ATTRELI_EL(priv->rx_stash_size) |
                ATTRELI_EI(priv->rx_stash_index);

        gfar_write(&priv->regs->attreli, attrs);

        /* Start with defaults, and add stashing or locking
         * depending on the approprate variables */
        attrs = ATTR_INIT_SETTINGS;

        if (priv->bd_stash_en)
                attrs |= ATTR_BDSTASH;

        if (priv->rx_stash_size != 0)
                attrs |= ATTR_BUFSTASH;

        gfar_write(&priv->regs->attr, attrs);

        gfar_write(&priv->regs->fifo_tx_thr, priv->fifo_threshold);
        gfar_write(&priv->regs->fifo_tx_starve, priv->fifo_starve);
        gfar_write(&priv->regs->fifo_tx_starve_shutoff, priv->fifo_starve_off);

        /* Start the controller */
        gfar_start(dev);

        return 0;

rx_irq_fail:
        free_irq(priv->interruptTransmit, dev);
tx_irq_fail:
        free_irq(priv->interruptError, dev);
err_irq_fail:
rx_skb_fail:
        free_skb_resources(priv);
tx_skb_fail:
        dma_free_coherent(NULL,
                        sizeof(struct txbd8)*priv->tx_ring_size
                        + sizeof(struct rxbd8)*priv->rx_ring_size,
                        priv->tx_bd_base,
                        gfar_read(&regs->tbase0));

        return err;
}

/* Called when something needs to use the ethernet device */
/* Returns 0 for success. */
static int gfar_enet_open(struct net_device *dev)
{
        int err;

        /* Initialize a bunch of registers */
        init_registers(dev);

        gfar_set_mac_address(dev);

        err = init_phy(dev);

        if(err)
                return err;

        err = startup_gfar(dev);

        netif_start_queue(dev);

        return err;
}

static inline struct txfcb *gfar_add_fcb(struct sk_buff *skb, struct txbd8 *bdp)
{
        struct txfcb *fcb = (struct txfcb *)skb_push (skb, GMAC_FCB_LEN);

        memset(fcb, 0, GMAC_FCB_LEN);

        return fcb;
}

static inline void gfar_tx_checksum(struct sk_buff *skb, struct txfcb *fcb)
{
        u8 flags = 0;

        /* If we're here, it's a IP packet with a TCP or UDP
         * payload.  We set it to checksum, using a pseudo-header
         * we provide
         */
        flags = TXFCB_DEFAULT;

        /* Tell the controller what the protocol is */
        /* And provide the already calculated phcs */
        if (skb->nh.iph->protocol == IPPROTO_UDP) {
                flags |= TXFCB_UDP;
                fcb->phcs = skb->h.uh->check;
        } else
                fcb->phcs = skb->h.th->check;

        /* l3os is the distance between the start of the
         * frame (skb->data) and the start of the IP hdr.
         * l4os is the distance between the start of the
         * l3 hdr and the l4 hdr */
        fcb->l3os = (u16)(skb->nh.raw - skb->data - GMAC_FCB_LEN);
        fcb->l4os = (u16)(skb->h.raw - skb->nh.raw);

        fcb->flags = flags;
}

void inline gfar_tx_vlan(struct sk_buff *skb, struct txfcb *fcb)
{
        fcb->flags |= TXFCB_VLN;
        fcb->vlctl = vlan_tx_tag_get(skb);
}

/* This is called by the kernel when a frame is ready for transmission. */
/* It is pointed to by the dev->hard_start_xmit function pointer */
static int gfar_start_xmit(struct sk_buff *skb, struct net_device *dev)
{
        struct gfar_private *priv = netdev_priv(dev);
        struct txfcb *fcb = NULL;
        struct txbd8 *txbdp;
        u16 status;

        /* Update transmit stats */
        priv->stats.tx_bytes += skb->len;

        /* Lock priv now */
        spin_lock_irq(&priv->lock);

        /* Point at the first free tx descriptor */
        txbdp = priv->cur_tx;

        /* Clear all but the WRAP status flags */
        status = txbdp->status & TXBD_WRAP;

        /* Set up checksumming */
        if (likely((dev->features & NETIF_F_IP_CSUM)
                        && (CHECKSUM_HW == skb->ip_summed))) {
                fcb = gfar_add_fcb(skb, txbdp);
                status |= TXBD_TOE;
                gfar_tx_checksum(skb, fcb);
        }

        if (priv->vlan_enable &&
                        unlikely(priv->vlgrp && vlan_tx_tag_present(skb))) {
                if (unlikely(NULL == fcb)) {
                        fcb = gfar_add_fcb(skb, txbdp);
                        status |= TXBD_TOE;
                }

                gfar_tx_vlan(skb, fcb);
        }

        /* Set buffer length and pointer */
        txbdp->length = skb->len;
        txbdp->bufPtr = dma_map_single(NULL, skb->data,
                        skb->len, DMA_TO_DEVICE);

        /* Save the skb pointer so we can free it later */
        priv->tx_skbuff[priv->skb_curtx] = skb;

        /* Update the current skb pointer (wrapping if this was the last) */
        priv->skb_curtx =
            (priv->skb_curtx + 1) & TX_RING_MOD_MASK(priv->tx_ring_size);

        /* Flag the BD as interrupt-causing */
        status |= TXBD_INTERRUPT;

        /* Flag the BD as ready to go, last in frame, and  */
        /* in need of CRC */
        status |= (TXBD_READY | TXBD_LAST | TXBD_CRC);

        dev->trans_start = jiffies;

        txbdp->status = status;

        /* If this was the last BD in the ring, the next one */
        /* is at the beginning of the ring */
        if (txbdp->status & TXBD_WRAP)
                txbdp = priv->tx_bd_base;
        else
                txbdp++;

        /* If the next BD still needs to be cleaned up, then the bds
           are full.  We need to tell the kernel to stop sending us stuff. */
        if (txbdp == priv->dirty_tx) {
                netif_stop_queue(dev);

                priv->stats.tx_fifo_errors++;
        }

        /* Update the current txbd to the next one */
        priv->cur_tx = txbdp;

        /* Tell the DMA to go go go */
        gfar_write(&priv->regs->tstat, TSTAT_CLEAR_THALT);

        /* Unlock priv */
        spin_unlock_irq(&priv->lock);

        return 0;
}

/* Stops the kernel queue, and halts the controller */
static int gfar_close(struct net_device *dev)
{
        struct gfar_private *priv = netdev_priv(dev);
        stop_gfar(dev);

        /* Disconnect from the PHY */
        phy_disconnect(priv->phydev);
        priv->phydev = NULL;

        netif_stop_queue(dev);

        return 0;
}

/* returns a net_device_stats structure pointer */
static struct net_device_stats * gfar_get_stats(struct net_device *dev)
{
        struct gfar_private *priv = netdev_priv(dev);

        return &(priv->stats);
}

/* Changes the mac address if the controller is not running. */
int gfar_set_mac_address(struct net_device *dev)
{
        gfar_set_mac_for_addr(dev, 0, dev->dev_addr);

        return 0;
}


/* Enables and disables VLAN insertion/extraction */
static void gfar_vlan_rx_register(struct net_device *dev,
                struct vlan_group *grp)
{
        struct gfar_private *priv = netdev_priv(dev);
        unsigned long flags;
        u32 tempval;

        spin_lock_irqsave(&priv->lock, flags);

        priv->vlgrp = grp;

        if (grp) {
                /* Enable VLAN tag insertion */
                tempval = gfar_read(&priv->regs->tctrl);
                tempval |= TCTRL_VLINS;

                gfar_write(&priv->regs->tctrl, tempval);
                
                /* Enable VLAN tag extraction */
                tempval = gfar_read(&priv->regs->rctrl);
                tempval |= RCTRL_VLEX;
                gfar_write(&priv->regs->rctrl, tempval);
        } else {
                /* Disable VLAN tag insertion */
                tempval = gfar_read(&priv->regs->tctrl);
                tempval &= ~TCTRL_VLINS;
                gfar_write(&priv->regs->tctrl, tempval);

                /* Disable VLAN tag extraction */
                tempval = gfar_read(&priv->regs->rctrl);
                tempval &= ~RCTRL_VLEX;
                gfar_write(&priv->regs->rctrl, tempval);
        }

        spin_unlock_irqrestore(&priv->lock, flags);
}


static void gfar_vlan_rx_kill_vid(struct net_device *dev, uint16_t vid)
{
        struct gfar_private *priv = netdev_priv(dev);
        unsigned long flags;

        spin_lock_irqsave(&priv->lock, flags);

        if (priv->vlgrp)
                priv->vlgrp->vlan_devices[vid] = NULL;

        spin_unlock_irqrestore(&priv->lock, flags);
}


static int gfar_change_mtu(struct net_device *dev, int new_mtu)
{
        int tempsize, tempval;
        struct gfar_private *priv = netdev_priv(dev);
        int oldsize = priv->rx_buffer_size;
        int frame_size = new_mtu + ETH_HLEN;

        if (priv->vlan_enable)
                frame_size += VLAN_ETH_HLEN;

        if (gfar_uses_fcb(priv))
                frame_size += GMAC_FCB_LEN;

        frame_size += priv->padding;

        if ((frame_size < 64) || (frame_size > JUMBO_FRAME_SIZE)) {
                if (netif_msg_drv(priv))
                        printk(KERN_ERR "%s: Invalid MTU setting\n",
                                        dev->name);
                return -EINVAL;
        }

        tempsize =
            (frame_size & ~(INCREMENTAL_BUFFER_SIZE - 1)) +
            INCREMENTAL_BUFFER_SIZE;

        /* Only stop and start the controller if it isn't already
         * stopped, and we changed something */
        if ((oldsize != tempsize) && (dev->flags & IFF_UP))
                stop_gfar(dev);

        priv->rx_buffer_size = tempsize;

        dev->mtu = new_mtu;

        gfar_write(&priv->regs->mrblr, priv->rx_buffer_size);
        gfar_write(&priv->regs->maxfrm, priv->rx_buffer_size);

        /* If the mtu is larger than the max size for standard
         * ethernet frames (ie, a jumbo frame), then set maccfg2
         * to allow huge frames, and to check the length */
        tempval = gfar_read(&priv->regs->maccfg2);

        if (priv->rx_buffer_size > DEFAULT_RX_BUFFER_SIZE)
                tempval |= (MACCFG2_HUGEFRAME | MACCFG2_LENGTHCHECK);
        else
                tempval &= ~(MACCFG2_HUGEFRAME | MACCFG2_LENGTHCHECK);

        gfar_write(&priv->regs->maccfg2, tempval);

        if ((oldsize != tempsize) && (dev->flags & IFF_UP))
                startup_gfar(dev);

        return 0;
}

/* gfar_timeout gets called when a packet has not been
 * transmitted after a set amount of time.
 * For now, assume that clearing out all the structures, and
 * starting over will fix the problem. */
static void gfar_timeout(struct net_device *dev)
{
        struct gfar_private *priv = netdev_priv(dev);

        priv->stats.tx_errors++;

        if (dev->flags & IFF_UP) {
                stop_gfar(dev);
                startup_gfar(dev);
        }

        netif_schedule(dev);
}

/* Interrupt Handler for Transmit complete */
static irqreturn_t gfar_transmit(int irq, void *dev_id, struct pt_regs *regs)
{
        struct net_device *dev = (struct net_device *) dev_id;
        struct gfar_private *priv = netdev_priv(dev);
        struct txbd8 *bdp;

        /* Clear IEVENT */
        gfar_write(&priv->regs->ievent, IEVENT_TX_MASK);

        /* Lock priv */
        spin_lock(&priv->lock);
        bdp = priv->dirty_tx;
        while ((bdp->status & TXBD_READY) == 0) {
                /* If dirty_tx and cur_tx are the same, then either the */
                /* ring is empty or full now (it could only be full in the beginning, */
                /* obviously).  If it is empty, we are done. */
                if ((bdp == priv->cur_tx) && (netif_queue_stopped(dev) == 0))
                        break;

                priv->stats.tx_packets++;

                /* Deferred means some collisions occurred during transmit, */
                /* but we eventually sent the packet. */
                if (bdp->status & TXBD_DEF)
                        priv->stats.collisions++;

                /* Free the sk buffer associated with this TxBD */
                dev_kfree_skb_irq(priv->tx_skbuff[priv->skb_dirtytx]);
                priv->tx_skbuff[priv->skb_dirtytx] = NULL;
                priv->skb_dirtytx =
                    (priv->skb_dirtytx +
                     1) & TX_RING_MOD_MASK(priv->tx_ring_size);

                /* update bdp to point at next bd in the ring (wrapping if necessary) */
                if (bdp->status & TXBD_WRAP)
                        bdp = priv->tx_bd_base;
                else
                        bdp++;

                /* Move dirty_tx to be the next bd */
                priv->dirty_tx = bdp;

                /* We freed a buffer, so now we can restart transmission */
                if (netif_queue_stopped(dev))
                        netif_wake_queue(dev);
        } /* while ((bdp->status & TXBD_READY) == 0) */

        /* If we are coalescing the interrupts, reset the timer */
        /* Otherwise, clear it */
        if (priv->txcoalescing)
                gfar_write(&priv->regs->txic,
                           mk_ic_value(priv->txcount, priv->txtime));
        else
                gfar_write(&priv->regs->txic, 0);

        spin_unlock(&priv->lock);

        return IRQ_HANDLED;
}

struct sk_buff * gfar_new_skb(struct net_device *dev, struct rxbd8 *bdp)
{
        unsigned int alignamount;
        struct gfar_private *priv = netdev_priv(dev);
        struct sk_buff *skb = NULL;
        unsigned int timeout = SKB_ALLOC_TIMEOUT;

        /* We have to allocate the skb, so keep trying till we succeed */
        while ((!skb) && timeout--)
                skb = dev_alloc_skb(priv->rx_buffer_size + RXBUF_ALIGNMENT);

        if (NULL == skb)
                return NULL;

        alignamount = RXBUF_ALIGNMENT -
                (((unsigned) skb->data) & (RXBUF_ALIGNMENT - 1));

        /* We need the data buffer to be aligned properly.  We will reserve
         * as many bytes as needed to align the data properly
         */
        skb_reserve(skb, alignamount);

        skb->dev = dev;

        bdp->bufPtr = dma_map_single(NULL, skb->data,
                        priv->rx_buffer_size, DMA_FROM_DEVICE);

        bdp->length = 0;

        /* Mark the buffer empty */
        bdp->status |= (RXBD_EMPTY | RXBD_INTERRUPT);

        return skb;
}

static inline void count_errors(unsigned short status, struct gfar_private *priv)
{
        struct net_device_stats *stats = &priv->stats;
        struct gfar_extra_stats *estats = &priv->extra_stats;

        /* If the packet was truncated, none of the other errors
         * matter */
        if (status & RXBD_TRUNCATED) {
                stats->rx_length_errors++;

                estats->rx_trunc++;

                return;
        }
        /* Count the errors, if there were any */
        if (status & (RXBD_LARGE | RXBD_SHORT)) {
                stats->rx_length_errors++;

                if (status & RXBD_LARGE)
                        estats->rx_large++;
                else
                        estats->rx_short++;
        }
        if (status & RXBD_NONOCTET) {
                stats->rx_frame_errors++;
                estats->rx_nonoctet++;
        }
        if (status & RXBD_CRCERR) {
                estats->rx_crcerr++;
                stats->rx_crc_errors++;
        }
        if (status & RXBD_OVERRUN) {
                estats->rx_overrun++;
                stats->rx_crc_errors++;
        }
}

irqreturn_t gfar_receive(int irq, void *dev_id, struct pt_regs *regs)
{
        struct net_device *dev = (struct net_device *) dev_id;
        struct gfar_private *priv = netdev_priv(dev);

#ifdef CONFIG_GFAR_NAPI
        u32 tempval;
#endif

        /* Clear IEVENT, so rx interrupt isn't called again
         * because of this interrupt */
        gfar_write(&priv->regs->ievent, IEVENT_RX_MASK);

        /* support NAPI */
#ifdef CONFIG_GFAR_NAPI
        if (netif_rx_schedule_prep(dev)) {
                tempval = gfar_read(&priv->regs->imask);
                tempval &= IMASK_RX_DISABLED;
                gfar_write(&priv->regs->imask, tempval);

                __netif_rx_schedule(dev);
        } else {
                if (netif_msg_rx_err(priv))
                        printk(KERN_DEBUG "%s: receive called twice (%x)[%x]\n",
                                dev->name, gfar_read(&priv->regs->ievent),
                                gfar_read(&priv->regs->imask));
        }
#else

        spin_lock(&priv->lock);
        gfar_clean_rx_ring(dev, priv->rx_ring_size);

        /* If we are coalescing interrupts, update the timer */
        /* Otherwise, clear it */
        if (priv->rxcoalescing)
                gfar_write(&priv->regs->rxic,
                           mk_ic_value(priv->rxcount, priv->rxtime));
        else
                gfar_write(&priv->regs->rxic, 0);

        spin_unlock(&priv->lock);
#endif

        return IRQ_HANDLED;
}

static inline int gfar_rx_vlan(struct sk_buff *skb,
                struct vlan_group *vlgrp, unsigned short vlctl)
{
#ifdef CONFIG_GFAR_NAPI
        return vlan_hwaccel_receive_skb(skb, vlgrp, vlctl);
#else
        return vlan_hwaccel_rx(skb, vlgrp, vlctl);
#endif
}

static inline void gfar_rx_checksum(struct sk_buff *skb, struct rxfcb *fcb)
{
        /* If valid headers were found, and valid sums
         * were verified, then we tell the kernel that no
         * checksumming is necessary.  Otherwise, it is */
        if ((fcb->flags & RXFCB_CSUM_MASK) == (RXFCB_CIP | RXFCB_CTU))
                skb->ip_summed = CHECKSUM_UNNECESSARY;
        else
                skb->ip_summed = CHECKSUM_NONE;
}


static inline struct rxfcb *gfar_get_fcb(struct sk_buff *skb)
{
        struct rxfcb *fcb = (struct rxfcb *)skb->data;

        /* Remove the FCB from the skb */
        skb_pull(skb, GMAC_FCB_LEN);

        return fcb;
}

/* gfar_process_frame() -- handle one incoming packet if skb
 * isn't NULL.  */
static int gfar_process_frame(struct net_device *dev, struct sk_buff *skb,
                int length)
{
        struct gfar_private *priv = netdev_priv(dev);
        struct rxfcb *fcb = NULL;

        if (NULL == skb) {
                if (netif_msg_rx_err(priv))
                        printk(KERN_WARNING "%s: Missing skb!!.\n", dev->name);
                priv->stats.rx_dropped++;
                priv->extra_stats.rx_skbmissing++;
        } else {
                int ret;

                /* Prep the skb for the packet */
                skb_put(skb, length);

                /* Grab the FCB if there is one */
                if (gfar_uses_fcb(priv))
                        fcb = gfar_get_fcb(skb);

                /* Remove the padded bytes, if there are any */
                if (priv->padding)
                        skb_pull(skb, priv->padding);

                if (priv->rx_csum_enable)
                        gfar_rx_checksum(skb, fcb);

                /* Tell the skb what kind of packet this is */
                skb->protocol = eth_type_trans(skb, dev);

                /* Send the packet up the stack */
                if (unlikely(priv->vlgrp && (fcb->flags & RXFCB_VLN)))
                        ret = gfar_rx_vlan(skb, priv->vlgrp, fcb->vlctl);
                else
                        ret = RECEIVE(skb);

                if (NET_RX_DROP == ret)
                        priv->extra_stats.kernel_dropped++;
        }

        return 0;
}

/* gfar_clean_rx_ring() -- Processes each frame in the rx ring
 *   until the budget/quota has been reached. Returns the number
 *   of frames handled
 */
int gfar_clean_rx_ring(struct net_device *dev, int rx_work_limit)
{
        struct rxbd8 *bdp;
        struct sk_buff *skb;
        u16 pkt_len;
        int howmany = 0;
        struct gfar_private *priv = netdev_priv(dev);

        /* Get the first full descriptor */
        bdp = priv->cur_rx;

        while (!((bdp->status & RXBD_EMPTY) || (--rx_work_limit < 0))) {
                skb = priv->rx_skbuff[priv->skb_currx];

                if (!(bdp->status &
                      (RXBD_LARGE | RXBD_SHORT | RXBD_NONOCTET
                       | RXBD_CRCERR | RXBD_OVERRUN | RXBD_TRUNCATED))) {
                        /* Increment the number of packets */
                        priv->stats.rx_packets++;
                        howmany++;

                        /* Remove the FCS from the packet length */
                        pkt_len = bdp->length - 4;

                        gfar_process_frame(dev, skb, pkt_len);

                        priv->stats.rx_bytes += pkt_len;
                } else {
                        count_errors(bdp->status, priv);

                        if (skb)
                                dev_kfree_skb_any(skb);

                        priv->rx_skbuff[priv->skb_currx] = NULL;
                }

                dev->last_rx = jiffies;

                /* Clear the status flags for this buffer */
                bdp->status &= ~RXBD_STATS;

                /* Add another skb for the future */
                skb = gfar_new_skb(dev, bdp);
                priv->rx_skbuff[priv->skb_currx] = skb;

                /* Update to the next pointer */
                if (bdp->status & RXBD_WRAP)
                        bdp = priv->rx_bd_base;
                else
                        bdp++;

                /* update to point at the next skb */
                priv->skb_currx =
                    (priv->skb_currx +
                     1) & RX_RING_MOD_MASK(priv->rx_ring_size);

        }

        /* Update the current rxbd pointer to be the next one */
        priv->cur_rx = bdp;

        /* If no packets have arrived since the
         * last one we processed, clear the IEVENT RX and
         * BSY bits so that another interrupt won't be
         * generated when we set IMASK */
        if (bdp->status & RXBD_EMPTY)
                gfar_write(&priv->regs->ievent, IEVENT_RX_MASK);

        return howmany;
}

#ifdef CONFIG_GFAR_NAPI
static int gfar_poll(struct net_device *dev, int *budget)
{
        int howmany;
        struct gfar_private *priv = netdev_priv(dev);
        int rx_work_limit = *budget;

        if (rx_work_limit > dev->quota)
                rx_work_limit = dev->quota;

        howmany = gfar_clean_rx_ring(dev, rx_work_limit);

        dev->quota -= howmany;
        rx_work_limit -= howmany;
        *budget -= howmany;

        if (rx_work_limit >= 0) {
                netif_rx_complete(dev);

                /* Clear the halt bit in RSTAT */
                gfar_write(&priv->regs->rstat, RSTAT_CLEAR_RHALT);

                gfar_write(&priv->regs->imask, IMASK_DEFAULT);

                /* If we are coalescing interrupts, update the timer */
                /* Otherwise, clear it */
                if (priv->rxcoalescing)
                        gfar_write(&priv->regs->rxic,
                                   mk_ic_value(priv->rxcount, priv->rxtime));
                else
                        gfar_write(&priv->regs->rxic, 0);
        }

        return (rx_work_limit < 0) ? 1 : 0;
}
#endif

/* The interrupt handler for devices with one interrupt */
static irqreturn_t gfar_interrupt(int irq, void *dev_id, struct pt_regs *regs)
{
        struct net_device *dev = dev_id;
        struct gfar_private *priv = netdev_priv(dev);

        /* Save ievent for future reference */
        u32 events = gfar_read(&priv->regs->ievent);

        /* Clear IEVENT */
        gfar_write(&priv->regs->ievent, events);

        /* Check for reception */
        if ((events & IEVENT_RXF0) || (events & IEVENT_RXB0))
                gfar_receive(irq, dev_id, regs);

        /* Check for transmit completion */
        if ((events & IEVENT_TXF) || (events & IEVENT_TXB))
                gfar_transmit(irq, dev_id, regs);

        /* Update error statistics */
        if (events & IEVENT_TXE) {
                priv->stats.tx_errors++;

                if (events & IEVENT_LC)
                        priv->stats.tx_window_errors++;
                if (events & IEVENT_CRL)
                        priv->stats.tx_aborted_errors++;
                if (events & IEVENT_XFUN) {
                        if (netif_msg_tx_err(priv))
                                printk(KERN_WARNING "%s: tx underrun. dropped packet\n", dev->name);
                        priv->stats.tx_dropped++;
                        priv->extra_stats.tx_underrun++;

                        /* Reactivate the Tx Queues */
                        gfar_write(&priv->regs->tstat, TSTAT_CLEAR_THALT);
                }
        }
        if (events & IEVENT_BSY) {
                priv->stats.rx_errors++;
                priv->extra_stats.rx_bsy++;

                gfar_receive(irq, dev_id, regs);

#ifndef CONFIG_GFAR_NAPI
                /* Clear the halt bit in RSTAT */
                gfar_write(&priv->regs->rstat, RSTAT_CLEAR_RHALT);
#endif

                if (netif_msg_rx_err(priv))
                        printk(KERN_DEBUG "%s: busy error (rhalt: %x)\n",
                                        dev->name,
                                        gfar_read(&priv->regs->rstat));
        }
        if (events & IEVENT_BABR) {
                priv->stats.rx_errors++;
                priv->extra_stats.rx_babr++;

                if (netif_msg_rx_err(priv))
                        printk(KERN_DEBUG "%s: babbling error\n", dev->name);
        }
        if (events & IEVENT_EBERR) {
                priv->extra_stats.eberr++;
                if (netif_msg_rx_err(priv))
                        printk(KERN_DEBUG "%s: EBERR\n", dev->name);
        }
        if ((events & IEVENT_RXC) && (netif_msg_rx_err(priv)))
                        printk(KERN_DEBUG "%s: control frame\n", dev->name);

        if (events & IEVENT_BABT) {
                priv->extra_stats.tx_babt++;
                if (netif_msg_rx_err(priv))
                        printk(KERN_DEBUG "%s: babt error\n", dev->name);
        }

        return IRQ_HANDLED;
}

/* Called every time the controller might need to be made
 * aware of new link state.  The PHY code conveys this
 * information through variables in the phydev structure, and this
 * function converts those variables into the appropriate
 * register values, and can bring down the device if needed.
 */
static void adjust_link(struct net_device *dev)
{
        struct gfar_private *priv = netdev_priv(dev);
        struct gfar *regs = priv->regs;
        unsigned long flags;
        struct phy_device *phydev = priv->phydev;
        int new_state = 0;

        spin_lock_irqsave(&priv->lock, flags);
        if (phydev->link) {
                u32 tempval = gfar_read(&regs->maccfg2);
                u32 ecntrl = gfar_read(&regs->ecntrl);

                /* Now we make sure that we can be in full duplex mode.
                 * If not, we operate in half-duplex mode. */
                if (phydev->duplex != priv->oldduplex) {
                        new_state = 1;
                        if (!(phydev->duplex))
                                tempval &= ~(MACCFG2_FULL_DUPLEX);
                        else
                                tempval |= MACCFG2_FULL_DUPLEX;

                        priv->oldduplex = phydev->duplex;
                }

                if (phydev->speed != priv->oldspeed) {
                        new_state = 1;
                        switch (phydev->speed) {
                        case 1000:
                                tempval =
                                    ((tempval & ~(MACCFG2_IF)) | MACCFG2_GMII);
                                break;
                        case 100:
                        case 10:
                                tempval =
                                    ((tempval & ~(MACCFG2_IF)) | MACCFG2_MII);

                                /* Reduced mode distinguishes
                                 * between 10 and 100 */
                                if (phydev->speed == SPEED_100)
                                        ecntrl |= ECNTRL_R100;
                                else
                                        ecntrl &= ~(ECNTRL_R100);
                                break;
                        default:
                                if (netif_msg_link(priv))
                                        printk(KERN_WARNING
                                                "%s: Ack!  Speed (%d) is not 10/100/1000!\n",
                                                dev->name, phydev->speed);
                                break;
                        }

                        priv->oldspeed = phydev->speed;
                }

                gfar_write(&regs->maccfg2, tempval);
                gfar_write(&regs->ecntrl, ecntrl);

                if (!priv->oldlink) {
                        new_state = 1;
                        priv->oldlink = 1;
                        netif_schedule(dev);
                }
        } else if (priv->oldlink) {
                new_state = 1;
                priv->oldlink = 0;
                priv->oldspeed = 0;
                priv->oldduplex = -1;
        }

        if (new_state && netif_msg_link(priv))
                phy_print_status(phydev);

        spin_unlock_irqrestore(&priv->lock, flags);
}

/* Update the hash table based on the current list of multicast
 * addresses we subscribe to.  Also, change the promiscuity of
 * the device based on the flags (this function is called
 * whenever dev->flags is changed */
static void gfar_set_multi(struct net_device *dev)
{
        struct dev_mc_list *mc_ptr;
        struct gfar_private *priv = netdev_priv(dev);
        struct gfar *regs = priv->regs;
        u32 tempval;

        if(dev->flags & IFF_PROMISC) {
                if (netif_msg_drv(priv))
                        printk(KERN_INFO "%s: Entering promiscuous mode.\n",
                                        dev->name);
                /* Set RCTRL to PROM */
                tempval = gfar_read(&regs->rctrl);
                tempval |= RCTRL_PROM;
                gfar_write(&regs->rctrl, tempval);
        } else {
                /* Set RCTRL to not PROM */
                tempval = gfar_read(&regs->rctrl);
                tempval &= ~(RCTRL_PROM);
                gfar_write(&regs->rctrl, tempval);
        }
        
        if(dev->flags & IFF_ALLMULTI) {
                /* Set the hash to rx all multicast frames */
                gfar_write(&regs->igaddr0, 0xffffffff);
                gfar_write(&regs->igaddr1, 0xffffffff);
                gfar_write(&regs->igaddr2, 0xffffffff);
                gfar_write(&regs->igaddr3, 0xffffffff);
                gfar_write(&regs->igaddr4, 0xffffffff);
                gfar_write(&regs->igaddr5, 0xffffffff);
                gfar_write(&regs->igaddr6, 0xffffffff);
                gfar_write(&regs->igaddr7, 0xffffffff);
                gfar_write(&regs->gaddr0, 0xffffffff);
                gfar_write(&regs->gaddr1, 0xffffffff);
                gfar_write(&regs->gaddr2, 0xffffffff);
                gfar_write(&regs->gaddr3, 0xffffffff);
                gfar_write(&regs->gaddr4, 0xffffffff);
                gfar_write(&regs->gaddr5, 0xffffffff);
                gfar_write(&regs->gaddr6, 0xffffffff);
                gfar_write(&regs->gaddr7, 0xffffffff);
        } else {
                int em_num;
                int idx;

                /* zero out the hash */
                gfar_write(&regs->igaddr0, 0x0);
                gfar_write(&regs->igaddr1, 0x0);
                gfar_write(&regs->igaddr2, 0x0);
                gfar_write(&regs->igaddr3, 0x0);
                gfar_write(&regs->igaddr4, 0x0);
                gfar_write(&regs->igaddr5, 0x0);
                gfar_write(&regs->igaddr6, 0x0);
                gfar_write(&regs->igaddr7, 0x0);
                gfar_write(&regs->gaddr0, 0x0);
                gfar_write(&regs->gaddr1, 0x0);
                gfar_write(&regs->gaddr2, 0x0);
                gfar_write(&regs->gaddr3, 0x0);
                gfar_write(&regs->gaddr4, 0x0);
                gfar_write(&regs->gaddr5, 0x0);
                gfar_write(&regs->gaddr6, 0x0);
                gfar_write(&regs->gaddr7, 0x0);

                /* If we have extended hash tables, we need to
                 * clear the exact match registers to prepare for
                 * setting them */
                if (priv->extended_hash) {
                        em_num = GFAR_EM_NUM + 1;
                        gfar_clear_exact_match(dev);
                        idx = 1;
                } else {
                        idx = 0;
                        em_num = 0;
                }

                if(dev->mc_count == 0)
                        return;

                /* Parse the list, and set the appropriate bits */
                for(mc_ptr = dev->mc_list; mc_ptr; mc_ptr = mc_ptr->next) {
                        if (idx < em_num) {
                                gfar_set_mac_for_addr(dev, idx,
                                                mc_ptr->dmi_addr);
                                idx++;
                        } else
                                gfar_set_hash_for_addr(dev, mc_ptr->dmi_addr);
                }
        }

        return;
}


/* Clears each of the exact match registers to zero, so they
 * don't interfere with normal reception */
static void gfar_clear_exact_match(struct net_device *dev)
{
        int idx;
        u8 zero_arr[MAC_ADDR_LEN] = {0,0,0,0,0,0};

        for(idx = 1;idx < GFAR_EM_NUM + 1;idx++)
                gfar_set_mac_for_addr(dev, idx, (u8 *)zero_arr);
}

/* Set the appropriate hash bit for the given addr */
/* The algorithm works like so:
 * 1) Take the Destination Address (ie the multicast address), and
 * do a CRC on it (little endian), and reverse the bits of the
 * result.
 * 2) Use the 8 most significant bits as a hash into a 256-entry
 * table.  The table is controlled through 8 32-bit registers:
 * gaddr0-7.  gaddr0's MSB is entry 0, and gaddr7's LSB is
 * gaddr7.  This means that the 3 most significant bits in the
 * hash index which gaddr register to use, and the 5 other bits
 * indicate which bit (assuming an IBM numbering scheme, which
 * for PowerPC (tm) is usually the case) in the register holds
 * the entry. */
static void gfar_set_hash_for_addr(struct net_device *dev, u8 *addr)
{
        u32 tempval;
        struct gfar_private *priv = netdev_priv(dev);
        u32 result = ether_crc(MAC_ADDR_LEN, addr);
        int width = priv->hash_width;
        u8 whichbit = (result >> (32 - width)) & 0x1f;
        u8 whichreg = result >> (32 - width + 5);
        u32 value = (1 << (31-whichbit));

        tempval = gfar_read(priv->hash_regs[whichreg]);
        tempval |= value;
        gfar_write(priv->hash_regs[whichreg], tempval);

        return;
}


/* There are multiple MAC Address register pairs on some controllers
 * This function sets the numth pair to a given address
 */
static void gfar_set_mac_for_addr(struct net_device *dev, int num, u8 *addr)
{
        struct gfar_private *priv = netdev_priv(dev);
        int idx;
        char tmpbuf[MAC_ADDR_LEN];
        u32 tempval;
        u32 *macptr = &priv->regs->macstnaddr1;

        macptr += num*2;

        /* Now copy it into the mac registers backwards, cuz */
        /* little endian is silly */
        for (idx = 0; idx < MAC_ADDR_LEN; idx++)
                tmpbuf[MAC_ADDR_LEN - 1 - idx] = addr[idx];

        gfar_write(macptr, *((u32 *) (tmpbuf)));

        tempval = *((u32 *) (tmpbuf + 4));

        gfar_write(macptr+1, tempval);
}

/* GFAR error interrupt handler */
static irqreturn_t gfar_error(int irq, void *dev_id, struct pt_regs *regs)
{
        struct net_device *dev = dev_id;
        struct gfar_private *priv = netdev_priv(dev);

        /* Save ievent for future reference */
        u32 events = gfar_read(&priv->regs->ievent);

        /* Clear IEVENT */
        gfar_write(&priv->regs->ievent, IEVENT_ERR_MASK);

        /* Hmm... */
        if (netif_msg_rx_err(priv) || netif_msg_tx_err(priv))
                printk(KERN_DEBUG "%s: error interrupt (ievent=0x%08x imask=0x%08x)\n",
                                dev->name, events, gfar_read(&priv->regs->imask));

        /* Update the error counters */
        if (events & IEVENT_TXE) {
                priv->stats.tx_errors++;

                if (events & IEVENT_LC)
                        priv->stats.tx_window_errors++;
                if (events & IEVENT_CRL)
                        priv->stats.tx_aborted_errors++;
                if (events & IEVENT_XFUN) {
                        if (netif_msg_tx_err(priv))
                                printk(KERN_DEBUG "%s: underrun.  packet dropped.\n",
                                                dev->name);
                        priv->stats.tx_dropped++;
                        priv->extra_stats.tx_underrun++;

                        /* Reactivate the Tx Queues */
                        gfar_write(&priv->regs->tstat, TSTAT_CLEAR_THALT);
                }
                if (netif_msg_tx_err(priv))
                        printk(KERN_DEBUG "%s: Transmit Error\n", dev->name);
        }
        if (events & IEVENT_BSY) {
                priv->stats.rx_errors++;
                priv->extra_stats.rx_bsy++;

                gfar_receive(irq, dev_id, regs);

#ifndef CONFIG_GFAR_NAPI
                /* Clear the halt bit in RSTAT */
                gfar_write(&priv->regs->rstat, RSTAT_CLEAR_RHALT);
#endif

                if (netif_msg_rx_err(priv))
                        printk(KERN_DEBUG "%s: busy error (rhalt: %x)\n",
                                        dev->name,
                                        gfar_read(&priv->regs->rstat));
        }
        if (events & IEVENT_BABR) {
                priv->stats.rx_errors++;
                priv->extra_stats.rx_babr++;

                if (netif_msg_rx_err(priv))
                        printk(KERN_DEBUG "%s: babbling error\n", dev->name);
        }
        if (events & IEVENT_EBERR) {
                priv->extra_stats.eberr++;
                if (netif_msg_rx_err(priv))
                        printk(KERN_DEBUG "%s: EBERR\n", dev->name);
        }
        if ((events & IEVENT_RXC) && netif_msg_rx_status(priv))
                if (netif_msg_rx_status(priv))
                        printk(KERN_DEBUG "%s: control frame\n", dev->name);

        if (events & IEVENT_BABT) {
                priv->extra_stats.tx_babt++;
                if (netif_msg_tx_err(priv))
                        printk(KERN_DEBUG "%s: babt error\n", dev->name);
        }
        return IRQ_HANDLED;
}

/* Structure for a device driver */
static struct platform_driver gfar_driver = {
        .probe = gfar_probe,
        .remove = gfar_remove,
        .driver = {
                .name = "fsl-gianfar",
        },
};

static int __init gfar_init(void)
{
        int err = gfar_mdio_init();

        if (err)
                return err;

        err = platform_driver_register(&gfar_driver);

        if (err)
                gfar_mdio_exit();
        
        return err;
}

static void __exit gfar_exit(void)
{
        platform_driver_unregister(&gfar_driver);
        gfar_mdio_exit();
}

module_init(gfar_init);
module_exit(gfar_exit);