Linux 2.6.17.7

[linux/fpc-iii.git] / drivers / net / arm / at91_ether.c

/*
 * Ethernet driver for the Atmel AT91RM9200 (Thunder)
 *
 *  Copyright (C) 2003 SAN People (Pty) Ltd
 *
 * Based on an earlier Atmel EMAC macrocell driver by Atmel and Lineo Inc.
 * Initial version by Rick Bronson 01/11/2003
 *
 * Intel LXT971A PHY support by Christopher Bahns & David Knickerbocker
 *   (Polaroid Corporation)
 *
 * Realtek RTL8201(B)L PHY support by Roman Avramenko <roman@imsystems.ru>
 *
 * 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/config.h>
#include <linux/mii.h>
#include <linux/netdevice.h>
#include <linux/etherdevice.h>
#include <linux/skbuff.h>
#include <linux/dma-mapping.h>
#include <linux/ethtool.h>
#include <linux/platform_device.h>
#include <linux/clk.h>

#include <asm/io.h>
#include <asm/uaccess.h>
#include <asm/mach-types.h>

#include <asm/arch/at91rm9200_emac.h>
#include <asm/arch/gpio.h>
#include <asm/arch/board.h>

#include "at91_ether.h"

#define DRV_NAME        "at91_ether"
#define DRV_VERSION     "1.0"

static struct net_device *at91_dev;
static struct clk *ether_clk;

/* ..................................................................... */

/*
 * Read from a EMAC register.
 */
static inline unsigned long at91_emac_read(unsigned int reg)
{
        void __iomem *emac_base = (void __iomem *)AT91_VA_BASE_EMAC;

        return __raw_readl(emac_base + reg);
}

/*
 * Write to a EMAC register.
 */
static inline void at91_emac_write(unsigned int reg, unsigned long value)
{
        void __iomem *emac_base = (void __iomem *)AT91_VA_BASE_EMAC;

        __raw_writel(value, emac_base + reg);
}

/* ........................... PHY INTERFACE ........................... */

/*
 * Enable the MDIO bit in MAC control register
 * When not called from an interrupt-handler, access to the PHY must be
 *  protected by a spinlock.
 */
static void enable_mdi(void)
{
        unsigned long ctl;

        ctl = at91_emac_read(AT91_EMAC_CTL);
        at91_emac_write(AT91_EMAC_CTL, ctl | AT91_EMAC_MPE);    /* enable management port */
}

/*
 * Disable the MDIO bit in the MAC control register
 */
static void disable_mdi(void)
{
        unsigned long ctl;

        ctl = at91_emac_read(AT91_EMAC_CTL);
        at91_emac_write(AT91_EMAC_CTL, ctl & ~AT91_EMAC_MPE);   /* disable management port */
}

/*
 * Wait until the PHY operation is complete.
 */
static inline void at91_phy_wait(void) {
        unsigned long timeout = jiffies + 2;

        while (!(at91_emac_read(AT91_EMAC_SR) & AT91_EMAC_SR_IDLE)) {
                if (time_after(jiffies, timeout)) {
                        printk("at91_ether: MIO timeout\n");
                        break;
                }
                cpu_relax();
        }
}

/*
 * Write value to the a PHY register
 * Note: MDI interface is assumed to already have been enabled.
 */
static void write_phy(unsigned char phy_addr, unsigned char address, unsigned int value)
{
        at91_emac_write(AT91_EMAC_MAN, AT91_EMAC_MAN_802_3 | AT91_EMAC_RW_W
                | ((phy_addr & 0x1f) << 23) | (address << 18) | (value & AT91_EMAC_DATA));

        /* Wait until IDLE bit in Network Status register is cleared */
        at91_phy_wait();
}

/*
 * Read value stored in a PHY register.
 * Note: MDI interface is assumed to already have been enabled.
 */
static void read_phy(unsigned char phy_addr, unsigned char address, unsigned int *value)
{
        at91_emac_write(AT91_EMAC_MAN, AT91_EMAC_MAN_802_3 | AT91_EMAC_RW_R
                | ((phy_addr & 0x1f) << 23) | (address << 18));

        /* Wait until IDLE bit in Network Status register is cleared */
        at91_phy_wait();

        *value = at91_emac_read(AT91_EMAC_MAN) & AT91_EMAC_DATA;
}

/* ........................... PHY MANAGEMENT .......................... */

/*
 * Access the PHY to determine the current link speed and mode, and update the
 * MAC accordingly.
 * If no link or auto-negotiation is busy, then no changes are made.
 */
static void update_linkspeed(struct net_device *dev)
{
        struct at91_private *lp = (struct at91_private *) dev->priv;
        unsigned int bmsr, bmcr, lpa, mac_cfg;
        unsigned int speed, duplex;

        if (!mii_link_ok(&lp->mii)) {           /* no link */
                netif_carrier_off(dev);
                printk(KERN_INFO "%s: Link down.\n", dev->name);
                return;
        }

        /* Link up, or auto-negotiation still in progress */
        read_phy(lp->phy_address, MII_BMSR, &bmsr);
        read_phy(lp->phy_address, MII_BMCR, &bmcr);
        if (bmcr & BMCR_ANENABLE) {                             /* AutoNegotiation is enabled */
                if (!(bmsr & BMSR_ANEGCOMPLETE))
                        return;                 /* Do nothing - another interrupt generated when negotiation complete */

                read_phy(lp->phy_address, MII_LPA, &lpa);
                if ((lpa & LPA_100FULL) || (lpa & LPA_100HALF)) speed = SPEED_100;
                else speed = SPEED_10;
                if ((lpa & LPA_100FULL) || (lpa & LPA_10FULL)) duplex = DUPLEX_FULL;
                else duplex = DUPLEX_HALF;
        } else {
                speed = (bmcr & BMCR_SPEED100) ? SPEED_100 : SPEED_10;
                duplex = (bmcr & BMCR_FULLDPLX) ? DUPLEX_FULL : DUPLEX_HALF;
        }

        /* Update the MAC */
        mac_cfg = at91_emac_read(AT91_EMAC_CFG) & ~(AT91_EMAC_SPD | AT91_EMAC_FD);
        if (speed == SPEED_100) {
                if (duplex == DUPLEX_FULL)              /* 100 Full Duplex */
                        mac_cfg |= AT91_EMAC_SPD | AT91_EMAC_FD;
                else                                    /* 100 Half Duplex */
                        mac_cfg |= AT91_EMAC_SPD;
        } else {
                if (duplex == DUPLEX_FULL)              /* 10 Full Duplex */
                        mac_cfg |= AT91_EMAC_FD;
                else {}                                 /* 10 Half Duplex */
        }
        at91_emac_write(AT91_EMAC_CFG, mac_cfg);

        printk(KERN_INFO "%s: Link now %i-%s\n", dev->name, speed, (duplex == DUPLEX_FULL) ? "FullDuplex" : "HalfDuplex");
        netif_carrier_on(dev);
}

/*
 * Handle interrupts from the PHY
 */
static irqreturn_t at91ether_phy_interrupt(int irq, void *dev_id, struct pt_regs *regs)
{
        struct net_device *dev = (struct net_device *) dev_id;
        struct at91_private *lp = (struct at91_private *) dev->priv;
        unsigned int phy;

        /*
         * This hander is triggered on both edges, but the PHY chips expect
         * level-triggering.  We therefore have to check if the PHY actually has
         * an IRQ pending.
         */
        enable_mdi();
        if ((lp->phy_type == MII_DM9161_ID) || (lp->phy_type == MII_DM9161A_ID)) {
                read_phy(lp->phy_address, MII_DSINTR_REG, &phy);        /* ack interrupt in Davicom PHY */
                if (!(phy & (1 << 0)))
                        goto done;
        }
        else if (lp->phy_type == MII_LXT971A_ID) {
                read_phy(lp->phy_address, MII_ISINTS_REG, &phy);        /* ack interrupt in Intel PHY */
                if (!(phy & (1 << 2)))
                        goto done;
        }
        else if (lp->phy_type == MII_BCM5221_ID) {
                read_phy(lp->phy_address, MII_BCMINTR_REG, &phy);       /* ack interrupt in Broadcom PHY */
                if (!(phy & (1 << 0)))
                        goto done;
        }
        else if (lp->phy_type == MII_KS8721_ID) {
                read_phy(lp->phy_address, MII_TPISTATUS, &phy);         /* ack interrupt in Micrel PHY */
                if (!(phy & ((1 << 2) | 1)))
                        goto done;
        }

        update_linkspeed(dev);

done:
        disable_mdi();

        return IRQ_HANDLED;
}

/*
 * Initialize and enable the PHY interrupt for link-state changes
 */
static void enable_phyirq(struct net_device *dev)
{
        struct at91_private *lp = (struct at91_private *) dev->priv;
        unsigned int dsintr, irq_number;
        int status;

        if (lp->phy_type == MII_RTL8201_ID)     /* RTL8201 does not have an interrupt */
                return;
        if (lp->phy_type == MII_DP83847_ID)     /* DP83847 does not have an interrupt */
                return;
        if (lp->phy_type == MII_AC101L_ID)      /* AC101L interrupt not supported yet */
                return;

        irq_number = lp->board_data.phy_irq_pin;
        status = request_irq(irq_number, at91ether_phy_interrupt, 0, dev->name, dev);
        if (status) {
                printk(KERN_ERR "at91_ether: PHY IRQ %d request failed - status %d!\n", irq_number, status);
                return;
        }

        spin_lock_irq(&lp->lock);
        enable_mdi();

        if ((lp->phy_type == MII_DM9161_ID) || (lp->phy_type == MII_DM9161A_ID)) {      /* for Davicom PHY */
                read_phy(lp->phy_address, MII_DSINTR_REG, &dsintr);
                dsintr = dsintr & ~0xf00;               /* clear bits 8..11 */
                write_phy(lp->phy_address, MII_DSINTR_REG, dsintr);
        }
        else if (lp->phy_type == MII_LXT971A_ID) {      /* for Intel PHY */
                read_phy(lp->phy_address, MII_ISINTE_REG, &dsintr);
                dsintr = dsintr | 0xf2;                 /* set bits 1, 4..7 */
                write_phy(lp->phy_address, MII_ISINTE_REG, dsintr);
        }
        else if (lp->phy_type == MII_BCM5221_ID) {      /* for Broadcom PHY */
                dsintr = (1 << 15) | ( 1 << 14);
                write_phy(lp->phy_address, MII_BCMINTR_REG, dsintr);
        }
        else if (lp->phy_type == MII_KS8721_ID) {       /* for Micrel PHY */
                dsintr = (1 << 10) | ( 1 << 8);
                write_phy(lp->phy_address, MII_TPISTATUS, dsintr);
        }

        disable_mdi();
        spin_unlock_irq(&lp->lock);
}

/*
 * Disable the PHY interrupt
 */
static void disable_phyirq(struct net_device *dev)
{
        struct at91_private *lp = (struct at91_private *) dev->priv;
        unsigned int dsintr;
        unsigned int irq_number;

        if (lp->phy_type == MII_RTL8201_ID)     /* RTL8201 does not have an interrupt */
                return;
        if (lp->phy_type == MII_DP83847_ID)     /* DP83847 does not have an interrupt */
                return;
        if (lp->phy_type == MII_AC101L_ID)      /* AC101L interrupt not supported yet */
                return;

        spin_lock_irq(&lp->lock);
        enable_mdi();

        if ((lp->phy_type == MII_DM9161_ID) || (lp->phy_type == MII_DM9161A_ID)) {      /* for Davicom PHY */
                read_phy(lp->phy_address, MII_DSINTR_REG, &dsintr);
                dsintr = dsintr | 0xf00;                        /* set bits 8..11 */
                write_phy(lp->phy_address, MII_DSINTR_REG, dsintr);
        }
        else if (lp->phy_type == MII_LXT971A_ID) {      /* for Intel PHY */
                read_phy(lp->phy_address, MII_ISINTE_REG, &dsintr);
                dsintr = dsintr & ~0xf2;                        /* clear bits 1, 4..7 */
                write_phy(lp->phy_address, MII_ISINTE_REG, dsintr);
        }
        else if (lp->phy_type == MII_BCM5221_ID) {      /* for Broadcom PHY */
                read_phy(lp->phy_address, MII_BCMINTR_REG, &dsintr);
                dsintr = ~(1 << 14);
                write_phy(lp->phy_address, MII_BCMINTR_REG, dsintr);
        }
        else if (lp->phy_type == MII_KS8721_ID) {       /* for Micrel PHY */
                read_phy(lp->phy_address, MII_TPISTATUS, &dsintr);
                dsintr = ~((1 << 10) | (1 << 8));
                write_phy(lp->phy_address, MII_TPISTATUS, dsintr);
        }

        disable_mdi();
        spin_unlock_irq(&lp->lock);

        irq_number = lp->board_data.phy_irq_pin;
        free_irq(irq_number, dev);                      /* Free interrupt handler */
}

/*
 * Perform a software reset of the PHY.
 */
#if 0
static void reset_phy(struct net_device *dev)
{
        struct at91_private *lp = (struct at91_private *) dev->priv;
        unsigned int bmcr;

        spin_lock_irq(&lp->lock);
        enable_mdi();

        /* Perform PHY reset */
        write_phy(lp->phy_address, MII_BMCR, BMCR_RESET);

        /* Wait until PHY reset is complete */
        do {
                read_phy(lp->phy_address, MII_BMCR, &bmcr);
        } while (!(bmcr && BMCR_RESET));

        disable_mdi();
        spin_unlock_irq(&lp->lock);
}
#endif

/* ......................... ADDRESS MANAGEMENT ........................ */

/*
 * NOTE: Your bootloader must always set the MAC address correctly before
 * booting into Linux.
 *
 * - It must always set the MAC address after reset, even if it doesn't
 *   happen to access the Ethernet while it's booting.  Some versions of
 *   U-Boot on the AT91RM9200-DK do not do this.
 *
 * - Likewise it must store the addresses in the correct byte order.
 *   MicroMonitor (uMon) on the CSB337 does this incorrectly (and
 *   continues to do so, for bug-compatibility).
 */

static short __init unpack_mac_address(struct net_device *dev, unsigned int hi, unsigned int lo)
{
        char addr[6];

        if (machine_is_csb337()) {
                addr[5] = (lo & 0xff);                  /* The CSB337 bootloader stores the MAC the wrong-way around */
                addr[4] = (lo & 0xff00) >> 8;
                addr[3] = (lo & 0xff0000) >> 16;
                addr[2] = (lo & 0xff000000) >> 24;
                addr[1] = (hi & 0xff);
                addr[0] = (hi & 0xff00) >> 8;
        }
        else {
                addr[0] = (lo & 0xff);
                addr[1] = (lo & 0xff00) >> 8;
                addr[2] = (lo & 0xff0000) >> 16;
                addr[3] = (lo & 0xff000000) >> 24;
                addr[4] = (hi & 0xff);
                addr[5] = (hi & 0xff00) >> 8;
        }

        if (is_valid_ether_addr(addr)) {
                memcpy(dev->dev_addr, &addr, 6);
                return 1;
        }
        return 0;
}

/*
 * Set the ethernet MAC address in dev->dev_addr
 */
static void __init get_mac_address(struct net_device *dev)
{
        /* Check Specific-Address 1 */
        if (unpack_mac_address(dev, at91_emac_read(AT91_EMAC_SA1H), at91_emac_read(AT91_EMAC_SA1L)))
                return;
        /* Check Specific-Address 2 */
        if (unpack_mac_address(dev, at91_emac_read(AT91_EMAC_SA2H), at91_emac_read(AT91_EMAC_SA2L)))
                return;
        /* Check Specific-Address 3 */
        if (unpack_mac_address(dev, at91_emac_read(AT91_EMAC_SA3H), at91_emac_read(AT91_EMAC_SA3L)))
                return;
        /* Check Specific-Address 4 */
        if (unpack_mac_address(dev, at91_emac_read(AT91_EMAC_SA4H), at91_emac_read(AT91_EMAC_SA4L)))
                return;

        printk(KERN_ERR "at91_ether: Your bootloader did not configure a MAC address.\n");
}

/*
 * Program the hardware MAC address from dev->dev_addr.
 */
static void update_mac_address(struct net_device *dev)
{
        at91_emac_write(AT91_EMAC_SA1L, (dev->dev_addr[3] << 24) | (dev->dev_addr[2] << 16) | (dev->dev_addr[1] << 8) | (dev->dev_addr[0]));
        at91_emac_write(AT91_EMAC_SA1H, (dev->dev_addr[5] << 8) | (dev->dev_addr[4]));

        at91_emac_write(AT91_EMAC_SA2L, 0);
        at91_emac_write(AT91_EMAC_SA2H, 0);
}

/*
 * Store the new hardware address in dev->dev_addr, and update the MAC.
 */
static int set_mac_address(struct net_device *dev, void* addr)
{
        struct sockaddr *address = addr;

        if (!is_valid_ether_addr(address->sa_data))
                return -EADDRNOTAVAIL;

        memcpy(dev->dev_addr, address->sa_data, dev->addr_len);
        update_mac_address(dev);

        printk("%s: Setting MAC address to %02x:%02x:%02x:%02x:%02x:%02x\n", dev->name,
                dev->dev_addr[0], dev->dev_addr[1], dev->dev_addr[2],
                dev->dev_addr[3], dev->dev_addr[4], dev->dev_addr[5]);

        return 0;
}

static int inline hash_bit_value(int bitnr, __u8 *addr)
{
        if (addr[bitnr / 8] & (1 << (bitnr % 8)))
                return 1;
        return 0;
}

/*
 * The hash address register is 64 bits long and takes up two locations in the memory map.
 * The least significant bits are stored in EMAC_HSL and the most significant
 * bits in EMAC_HSH.
 *
 * The unicast hash enable and the multicast hash enable bits in the network configuration
 *  register enable the reception of hash matched frames. The destination address is
 *  reduced to a 6 bit index into the 64 bit hash register using the following hash function.
 * The hash function is an exclusive or of every sixth bit of the destination address.
 *   hash_index[5] = da[5] ^ da[11] ^ da[17] ^ da[23] ^ da[29] ^ da[35] ^ da[41] ^ da[47]
 *   hash_index[4] = da[4] ^ da[10] ^ da[16] ^ da[22] ^ da[28] ^ da[34] ^ da[40] ^ da[46]
 *   hash_index[3] = da[3] ^ da[09] ^ da[15] ^ da[21] ^ da[27] ^ da[33] ^ da[39] ^ da[45]
 *   hash_index[2] = da[2] ^ da[08] ^ da[14] ^ da[20] ^ da[26] ^ da[32] ^ da[38] ^ da[44]
 *   hash_index[1] = da[1] ^ da[07] ^ da[13] ^ da[19] ^ da[25] ^ da[31] ^ da[37] ^ da[43]
 *   hash_index[0] = da[0] ^ da[06] ^ da[12] ^ da[18] ^ da[24] ^ da[30] ^ da[36] ^ da[42]
 * da[0] represents the least significant bit of the first byte received, that is, the multicast/
 *  unicast indicator, and da[47] represents the most significant bit of the last byte
 *  received.
 * If the hash index points to a bit that is set in the hash register then the frame will be
 *  matched according to whether the frame is multicast or unicast.
 * A multicast match will be signalled if the multicast hash enable bit is set, da[0] is 1 and
 *  the hash index points to a bit set in the hash register.
 * A unicast match will be signalled if the unicast hash enable bit is set, da[0] is 0 and the
 *  hash index points to a bit set in the hash register.
 * To receive all multicast frames, the hash register should be set with all ones and the
 *  multicast hash enable bit should be set in the network configuration register.
 */

/*
 * Return the hash index value for the specified address.
 */
static int hash_get_index(__u8 *addr)
{
        int i, j, bitval;
        int hash_index = 0;

        for (j = 0; j < 6; j++) {
                for (i = 0, bitval = 0; i < 8; i++)
                        bitval ^= hash_bit_value(i*6 + j, addr);

                hash_index |= (bitval << j);
        }

        return hash_index;
}

/*
 * Add multicast addresses to the internal multicast-hash table.
 */
static void at91ether_sethashtable(struct net_device *dev)
{
        struct dev_mc_list *curr;
        unsigned long mc_filter[2];
        unsigned int i, bitnr;

        mc_filter[0] = mc_filter[1] = 0;

        curr = dev->mc_list;
        for (i = 0; i < dev->mc_count; i++, curr = curr->next) {
                if (!curr) break;       /* unexpected end of list */

                bitnr = hash_get_index(curr->dmi_addr);
                mc_filter[bitnr >> 5] |= 1 << (bitnr & 31);
        }

        at91_emac_write(AT91_EMAC_HSH, mc_filter[0]);
        at91_emac_write(AT91_EMAC_HSL, mc_filter[1]);
}

/*
 * Enable/Disable promiscuous and multicast modes.
 */
static void at91ether_set_rx_mode(struct net_device *dev)
{
        unsigned long cfg;

        cfg = at91_emac_read(AT91_EMAC_CFG);

        if (dev->flags & IFF_PROMISC)                   /* Enable promiscuous mode */
                cfg |= AT91_EMAC_CAF;
        else if (dev->flags & (~IFF_PROMISC))           /* Disable promiscuous mode */
                cfg &= ~AT91_EMAC_CAF;

        if (dev->flags & IFF_ALLMULTI) {                /* Enable all multicast mode */
                at91_emac_write(AT91_EMAC_HSH, -1);
                at91_emac_write(AT91_EMAC_HSL, -1);
                cfg |= AT91_EMAC_MTI;
        } else if (dev->mc_count > 0) {                 /* Enable specific multicasts */
                at91ether_sethashtable(dev);
                cfg |= AT91_EMAC_MTI;
        } else if (dev->flags & (~IFF_ALLMULTI)) {      /* Disable all multicast mode */
                at91_emac_write(AT91_EMAC_HSH, 0);
                at91_emac_write(AT91_EMAC_HSL, 0);
                cfg &= ~AT91_EMAC_MTI;
        }

        at91_emac_write(AT91_EMAC_CFG, cfg);
}


/* ......................... ETHTOOL SUPPORT ........................... */


static int mdio_read(struct net_device *dev, int phy_id, int location)
{
        unsigned int value;

        read_phy(phy_id, location, &value);
        return value;
}

static void mdio_write(struct net_device *dev, int phy_id, int location, int value)
{
        write_phy(phy_id, location, value);
}

static int at91ether_get_settings(struct net_device *dev, struct ethtool_cmd *cmd)
{
        struct at91_private *lp = (struct at91_private *) dev->priv;
        int ret;

        spin_lock_irq(&lp->lock);
        enable_mdi();

        ret = mii_ethtool_gset(&lp->mii, cmd);

        disable_mdi();
        spin_unlock_irq(&lp->lock);

        if (lp->phy_media == PORT_FIBRE) {              /* override media type since mii.c doesn't know */
                cmd->supported = SUPPORTED_FIBRE;
                cmd->port = PORT_FIBRE;
        }

        return ret;
}

static int at91ether_set_settings(struct net_device *dev, struct ethtool_cmd *cmd)
{
        struct at91_private *lp = (struct at91_private *) dev->priv;
        int ret;

        spin_lock_irq(&lp->lock);
        enable_mdi();

        ret = mii_ethtool_sset(&lp->mii, cmd);

        disable_mdi();
        spin_unlock_irq(&lp->lock);

        return ret;
}

static int at91ether_nwayreset(struct net_device *dev)
{
        struct at91_private *lp = (struct at91_private *) dev->priv;
        int ret;

        spin_lock_irq(&lp->lock);
        enable_mdi();

        ret = mii_nway_restart(&lp->mii);

        disable_mdi();
        spin_unlock_irq(&lp->lock);

        return ret;
}

static void at91ether_get_drvinfo(struct net_device *dev, struct ethtool_drvinfo *info)
{
        strlcpy(info->driver, DRV_NAME, sizeof(info->driver));
        strlcpy(info->version, DRV_VERSION, sizeof(info->version));
        strlcpy(info->bus_info, dev->class_dev.dev->bus_id, sizeof(info->bus_info));
}

static struct ethtool_ops at91ether_ethtool_ops = {
        .get_settings   = at91ether_get_settings,
        .set_settings   = at91ether_set_settings,
        .get_drvinfo    = at91ether_get_drvinfo,
        .nway_reset     = at91ether_nwayreset,
        .get_link       = ethtool_op_get_link,
};


/* ................................ MAC ................................ */

/*
 * Initialize and start the Receiver and Transmit subsystems
 */
static void at91ether_start(struct net_device *dev)
{
        struct at91_private *lp = (struct at91_private *) dev->priv;
        struct recv_desc_bufs *dlist, *dlist_phys;
        int i;
        unsigned long ctl;

        dlist = lp->dlist;
        dlist_phys = lp->dlist_phys;

        for (i = 0; i < MAX_RX_DESCR; i++) {
                dlist->descriptors[i].addr = (unsigned int) &dlist_phys->recv_buf[i][0];
                dlist->descriptors[i].size = 0;
        }

        /* Set the Wrap bit on the last descriptor */
        dlist->descriptors[i-1].addr |= EMAC_DESC_WRAP;

        /* Reset buffer index */
        lp->rxBuffIndex = 0;

        /* Program address of descriptor list in Rx Buffer Queue register */
        at91_emac_write(AT91_EMAC_RBQP, (unsigned long) dlist_phys);

        /* Enable Receive and Transmit */
        ctl = at91_emac_read(AT91_EMAC_CTL);
        at91_emac_write(AT91_EMAC_CTL, ctl | AT91_EMAC_RE | AT91_EMAC_TE);
}

/*
 * Open the ethernet interface
 */
static int at91ether_open(struct net_device *dev)
{
        struct at91_private *lp = (struct at91_private *) dev->priv;
        unsigned long ctl;

        if (!is_valid_ether_addr(dev->dev_addr))
                return -EADDRNOTAVAIL;

        clk_enable(ether_clk);                  /* Re-enable Peripheral clock */

        /* Clear internal statistics */
        ctl = at91_emac_read(AT91_EMAC_CTL);
        at91_emac_write(AT91_EMAC_CTL, ctl | AT91_EMAC_CSR);

        /* Update the MAC address (incase user has changed it) */
        update_mac_address(dev);

        /* Enable PHY interrupt */
        enable_phyirq(dev);

        /* Enable MAC interrupts */
        at91_emac_write(AT91_EMAC_IER, AT91_EMAC_RCOM | AT91_EMAC_RBNA
                                | AT91_EMAC_TUND | AT91_EMAC_RTRY | AT91_EMAC_TCOM
                                | AT91_EMAC_ROVR | AT91_EMAC_ABT);

        /* Determine current link speed */
        spin_lock_irq(&lp->lock);
        enable_mdi();
        update_linkspeed(dev);
        disable_mdi();
        spin_unlock_irq(&lp->lock);

        at91ether_start(dev);
        netif_start_queue(dev);
        return 0;
}

/*
 * Close the interface
 */
static int at91ether_close(struct net_device *dev)
{
        unsigned long ctl;

        /* Disable Receiver and Transmitter */
        ctl = at91_emac_read(AT91_EMAC_CTL);
        at91_emac_write(AT91_EMAC_CTL, ctl & ~(AT91_EMAC_TE | AT91_EMAC_RE));

        /* Disable PHY interrupt */
        disable_phyirq(dev);

        /* Disable MAC interrupts */
        at91_emac_write(AT91_EMAC_IDR, AT91_EMAC_RCOM | AT91_EMAC_RBNA
                                | AT91_EMAC_TUND | AT91_EMAC_RTRY | AT91_EMAC_TCOM
                                | AT91_EMAC_ROVR | AT91_EMAC_ABT);

        netif_stop_queue(dev);

        clk_disable(ether_clk);                 /* Disable Peripheral clock */

        return 0;
}

/*
 * Transmit packet.
 */
static int at91ether_tx(struct sk_buff *skb, struct net_device *dev)
{
        struct at91_private *lp = (struct at91_private *) dev->priv;

        if (at91_emac_read(AT91_EMAC_TSR) & AT91_EMAC_TSR_BNQ) {
                netif_stop_queue(dev);

                /* Store packet information (to free when Tx completed) */
                lp->skb = skb;
                lp->skb_length = skb->len;
                lp->skb_physaddr = dma_map_single(NULL, skb->data, skb->len, DMA_TO_DEVICE);
                lp->stats.tx_bytes += skb->len;

                /* Set address of the data in the Transmit Address register */
                at91_emac_write(AT91_EMAC_TAR, lp->skb_physaddr);
                /* Set length of the packet in the Transmit Control register */
                at91_emac_write(AT91_EMAC_TCR, skb->len);

                dev->trans_start = jiffies;
        } else {
                printk(KERN_ERR "at91_ether.c: at91ether_tx() called, but device is busy!\n");
                return 1;       /* if we return anything but zero, dev.c:1055 calls kfree_skb(skb)
                                on this skb, he also reports -ENETDOWN and printk's, so either
                                we free and return(0) or don't free and return 1 */
        }

        return 0;
}

/*
 * Update the current statistics from the internal statistics registers.
 */
static struct net_device_stats *at91ether_stats(struct net_device *dev)
{
        struct at91_private *lp = (struct at91_private *) dev->priv;
        int ale, lenerr, seqe, lcol, ecol;

        if (netif_running(dev)) {
                lp->stats.rx_packets += at91_emac_read(AT91_EMAC_OK);           /* Good frames received */
                ale = at91_emac_read(AT91_EMAC_ALE);
                lp->stats.rx_frame_errors += ale;                               /* Alignment errors */
                lenerr = at91_emac_read(AT91_EMAC_ELR) + at91_emac_read(AT91_EMAC_USF);
                lp->stats.rx_length_errors += lenerr;                           /* Excessive Length or Undersize Frame error */
                seqe = at91_emac_read(AT91_EMAC_SEQE);
                lp->stats.rx_crc_errors += seqe;                                /* CRC error */
                lp->stats.rx_fifo_errors += at91_emac_read(AT91_EMAC_DRFC);     /* Receive buffer not available */
                lp->stats.rx_errors += (ale + lenerr + seqe
                        + at91_emac_read(AT91_EMAC_CDE) + at91_emac_read(AT91_EMAC_RJB));

                lp->stats.tx_packets += at91_emac_read(AT91_EMAC_FRA);          /* Frames successfully transmitted */
                lp->stats.tx_fifo_errors += at91_emac_read(AT91_EMAC_TUE);      /* Transmit FIFO underruns */
                lp->stats.tx_carrier_errors += at91_emac_read(AT91_EMAC_CSE);   /* Carrier Sense errors */
                lp->stats.tx_heartbeat_errors += at91_emac_read(AT91_EMAC_SQEE);/* Heartbeat error */

                lcol = at91_emac_read(AT91_EMAC_LCOL);
                ecol = at91_emac_read(AT91_EMAC_ECOL);
                lp->stats.tx_window_errors += lcol;                     /* Late collisions */
                lp->stats.tx_aborted_errors += ecol;                    /* 16 collisions */

                lp->stats.collisions += (at91_emac_read(AT91_EMAC_SCOL) + at91_emac_read(AT91_EMAC_MCOL) + lcol + ecol);
        }
        return &lp->stats;
}

/*
 * Extract received frame from buffer descriptors and sent to upper layers.
 * (Called from interrupt context)
 */
static void at91ether_rx(struct net_device *dev)
{
        struct at91_private *lp = (struct at91_private *) dev->priv;
        struct recv_desc_bufs *dlist;
        unsigned char *p_recv;
        struct sk_buff *skb;
        unsigned int pktlen;

        dlist = lp->dlist;
        while (dlist->descriptors[lp->rxBuffIndex].addr & EMAC_DESC_DONE) {
                p_recv = dlist->recv_buf[lp->rxBuffIndex];
                pktlen = dlist->descriptors[lp->rxBuffIndex].size & 0x7ff;      /* Length of frame including FCS */
                skb = alloc_skb(pktlen + 2, GFP_ATOMIC);
                if (skb != NULL) {
                        skb_reserve(skb, 2);
                        memcpy(skb_put(skb, pktlen), p_recv, pktlen);

                        skb->dev = dev;
                        skb->protocol = eth_type_trans(skb, dev);
                        skb->len = pktlen;
                        dev->last_rx = jiffies;
                        lp->stats.rx_bytes += pktlen;
                        netif_rx(skb);
                }
                else {
                        lp->stats.rx_dropped += 1;
                        printk(KERN_NOTICE "%s: Memory squeeze, dropping packet.\n", dev->name);
                }

                if (dlist->descriptors[lp->rxBuffIndex].size & EMAC_MULTICAST)
                        lp->stats.multicast++;

                dlist->descriptors[lp->rxBuffIndex].addr &= ~EMAC_DESC_DONE;    /* reset ownership bit */
                if (lp->rxBuffIndex == MAX_RX_DESCR-1)                          /* wrap after last buffer */
                        lp->rxBuffIndex = 0;
                else
                        lp->rxBuffIndex++;
        }
}

/*
 * MAC interrupt handler
 */
static irqreturn_t at91ether_interrupt(int irq, void *dev_id, struct pt_regs *regs)
{
        struct net_device *dev = (struct net_device *) dev_id;
        struct at91_private *lp = (struct at91_private *) dev->priv;
        unsigned long intstatus, ctl;

        /* MAC Interrupt Status register indicates what interrupts are pending.
           It is automatically cleared once read. */
        intstatus = at91_emac_read(AT91_EMAC_ISR);

        if (intstatus & AT91_EMAC_RCOM)         /* Receive complete */
                at91ether_rx(dev);

        if (intstatus & AT91_EMAC_TCOM) {               /* Transmit complete */
                /* The TCOM bit is set even if the transmission failed. */
                if (intstatus & (AT91_EMAC_TUND | AT91_EMAC_RTRY))
                        lp->stats.tx_errors += 1;

                if (lp->skb) {
                        dev_kfree_skb_irq(lp->skb);
                        lp->skb = NULL;
                        dma_unmap_single(NULL, lp->skb_physaddr, lp->skb_length, DMA_TO_DEVICE);
                }
                netif_wake_queue(dev);
        }

        /* Work-around for Errata #11 */
        if (intstatus & AT91_EMAC_RBNA) {
                ctl = at91_emac_read(AT91_EMAC_CTL);
                at91_emac_write(AT91_EMAC_CTL, ctl & ~AT91_EMAC_RE);
                at91_emac_write(AT91_EMAC_CTL, ctl | AT91_EMAC_RE);
        }

        if (intstatus & AT91_EMAC_ROVR)
                printk("%s: ROVR error\n", dev->name);

        return IRQ_HANDLED;
}

/*
 * Initialize the ethernet interface
 */
static int __init at91ether_setup(unsigned long phy_type, unsigned short phy_address, struct platform_device *pdev)
{
        struct at91_eth_data *board_data = pdev->dev.platform_data;
        struct net_device *dev;
        struct at91_private *lp;
        unsigned int val;
        int res;

        if (at91_dev)                   /* already initialized */
                return 0;

        dev = alloc_etherdev(sizeof(struct at91_private));
        if (!dev)
                return -ENOMEM;

        dev->base_addr = AT91_VA_BASE_EMAC;
        dev->irq = AT91_ID_EMAC;
        SET_MODULE_OWNER(dev);

        /* Install the interrupt handler */
        if (request_irq(dev->irq, at91ether_interrupt, 0, dev->name, dev)) {
                free_netdev(dev);
                return -EBUSY;
        }

        /* Allocate memory for DMA Receive descriptors */
        lp = (struct at91_private *)dev->priv;
        lp->dlist = (struct recv_desc_bufs *) dma_alloc_coherent(NULL, sizeof(struct recv_desc_bufs), (dma_addr_t *) &lp->dlist_phys, GFP_KERNEL);
        if (lp->dlist == NULL) {
                free_irq(dev->irq, dev);
                free_netdev(dev);
                return -ENOMEM;
        }
        lp->board_data = *board_data;
        platform_set_drvdata(pdev, dev);

        spin_lock_init(&lp->lock);

        ether_setup(dev);
        dev->open = at91ether_open;
        dev->stop = at91ether_close;
        dev->hard_start_xmit = at91ether_tx;
        dev->get_stats = at91ether_stats;
        dev->set_multicast_list = at91ether_set_rx_mode;
        dev->set_mac_address = set_mac_address;
        dev->ethtool_ops = &at91ether_ethtool_ops;

        SET_NETDEV_DEV(dev, &pdev->dev);

        get_mac_address(dev);           /* Get ethernet address and store it in dev->dev_addr */
        update_mac_address(dev);        /* Program ethernet address into MAC */

        at91_emac_write(AT91_EMAC_CTL, 0);

        if (lp->board_data.is_rmii)
                at91_emac_write(AT91_EMAC_CFG, AT91_EMAC_CLK_DIV32 | AT91_EMAC_BIG | AT91_EMAC_RMII);
        else
                at91_emac_write(AT91_EMAC_CFG, AT91_EMAC_CLK_DIV32 | AT91_EMAC_BIG);

        /* Perform PHY-specific initialization */
        spin_lock_irq(&lp->lock);
        enable_mdi();
        if ((phy_type == MII_DM9161_ID) || (lp->phy_type == MII_DM9161A_ID)) {
                read_phy(phy_address, MII_DSCR_REG, &val);
                if ((val & (1 << 10)) == 0)                     /* DSCR bit 10 is 0 -- fiber mode */
                        lp->phy_media = PORT_FIBRE;
        } else if (machine_is_csb337()) {
                /* mix link activity status into LED2 link state */
                write_phy(phy_address, MII_LEDCTRL_REG, 0x0d22);
        }
        disable_mdi();
        spin_unlock_irq(&lp->lock);

        lp->mii.dev = dev;              /* Support for ethtool */
        lp->mii.mdio_read = mdio_read;
        lp->mii.mdio_write = mdio_write;

        lp->phy_type = phy_type;        /* Type of PHY connected */
        lp->phy_address = phy_address;  /* MDI address of PHY */

        /* Register the network interface */
        res = register_netdev(dev);
        if (res) {
                free_irq(dev->irq, dev);
                free_netdev(dev);
                dma_free_coherent(NULL, sizeof(struct recv_desc_bufs), lp->dlist, (dma_addr_t)lp->dlist_phys);
                return res;
        }
        at91_dev = dev;

        /* Determine current link speed */
        spin_lock_irq(&lp->lock);
        enable_mdi();
        update_linkspeed(dev);
        disable_mdi();
        spin_unlock_irq(&lp->lock);
        netif_carrier_off(dev);         /* will be enabled in open() */

        /* Display ethernet banner */
        printk(KERN_INFO "%s: AT91 ethernet at 0x%08x int=%d %s%s (%02x:%02x:%02x:%02x:%02x:%02x)\n",
                dev->name, (uint) dev->base_addr, dev->irq,
                at91_emac_read(AT91_EMAC_CFG) & AT91_EMAC_SPD ? "100-" : "10-",
                at91_emac_read(AT91_EMAC_CFG) & AT91_EMAC_FD ? "FullDuplex" : "HalfDuplex",
                dev->dev_addr[0], dev->dev_addr[1], dev->dev_addr[2],
                dev->dev_addr[3], dev->dev_addr[4], dev->dev_addr[5]);
        if ((phy_type == MII_DM9161_ID) || (lp->phy_type == MII_DM9161A_ID))
                printk(KERN_INFO "%s: Davicom 9196 PHY %s\n", dev->name, (lp->phy_media == PORT_FIBRE) ? "(Fiber)" : "(Copper)");
        else if (phy_type == MII_LXT971A_ID)
                printk(KERN_INFO "%s: Intel LXT971A PHY\n", dev->name);
        else if (phy_type == MII_RTL8201_ID)
                printk(KERN_INFO "%s: Realtek RTL8201(B)L PHY\n", dev->name);
        else if (phy_type == MII_BCM5221_ID)
                printk(KERN_INFO "%s: Broadcom BCM5221 PHY\n", dev->name);
        else if (phy_type == MII_DP83847_ID)
                printk(KERN_INFO "%s: National Semiconductor DP83847 PHY\n", dev->name);
        else if (phy_type == MII_AC101L_ID)
                printk(KERN_INFO "%s: Altima AC101L PHY\n", dev->name);
        else if (phy_type == MII_KS8721_ID)
                printk(KERN_INFO "%s: Micrel KS8721 PHY\n", dev->name);

        return 0;
}

/*
 * Detect MAC and PHY and perform initialization
 */
static int __init at91ether_probe(struct platform_device *pdev)
{
        unsigned int phyid1, phyid2;
        int detected = -1;
        unsigned long phy_id;
        unsigned short phy_address = 0;

        ether_clk = clk_get(&pdev->dev, "ether_clk");
        if (!ether_clk) {
                printk(KERN_ERR "at91_ether: no clock defined\n");
                return -ENODEV;
        }
        clk_enable(ether_clk);                                  /* Enable Peripheral clock */

        while ((detected != 0) && (phy_address < 32)) {
                /* Read the PHY ID registers */
                enable_mdi();
                read_phy(phy_address, MII_PHYSID1, &phyid1);
                read_phy(phy_address, MII_PHYSID2, &phyid2);
                disable_mdi();

                phy_id = (phyid1 << 16) | (phyid2 & 0xfff0);
                switch (phy_id) {
                        case MII_DM9161_ID:             /* Davicom 9161: PHY_ID1 = 0x181, PHY_ID2 = B881 */
                        case MII_DM9161A_ID:            /* Davicom 9161A: PHY_ID1 = 0x181, PHY_ID2 = B8A0 */
                        case MII_LXT971A_ID:            /* Intel LXT971A: PHY_ID1 = 0x13, PHY_ID2 = 78E0 */
                        case MII_RTL8201_ID:            /* Realtek RTL8201: PHY_ID1 = 0, PHY_ID2 = 0x8201 */
                        case MII_BCM5221_ID:            /* Broadcom BCM5221: PHY_ID1 = 0x40, PHY_ID2 = 0x61e0 */
                        case MII_DP83847_ID:            /* National Semiconductor DP83847:  */
                        case MII_AC101L_ID:             /* Altima AC101L: PHY_ID1 = 0x22, PHY_ID2 = 0x5520 */
                        case MII_KS8721_ID:             /* Micrel KS8721: PHY_ID1 = 0x22, PHY_ID2 = 0x1610 */
                                detected = at91ether_setup(phy_id, phy_address, pdev);
                                break;
                }

                phy_address++;
        }

        clk_disable(ether_clk);                                 /* Disable Peripheral clock */

        return detected;
}

static int __devexit at91ether_remove(struct platform_device *pdev)
{
        struct at91_private *lp = (struct at91_private *) at91_dev->priv;

        unregister_netdev(at91_dev);
        free_irq(at91_dev->irq, at91_dev);
        dma_free_coherent(NULL, sizeof(struct recv_desc_bufs), lp->dlist, (dma_addr_t)lp->dlist_phys);
        clk_put(ether_clk);

        free_netdev(at91_dev);
        at91_dev = NULL;
        return 0;
}

static struct platform_driver at91ether_driver = {
        .probe          = at91ether_probe,
        .remove         = __devexit_p(at91ether_remove),
        /* FIXME:  support suspend and resume */
        .driver         = {
                .name   = DRV_NAME,
                .owner  = THIS_MODULE,
        },
};

static int __init at91ether_init(void)
{
        return platform_driver_register(&at91ether_driver);
}

static void __exit at91ether_exit(void)
{
        platform_driver_unregister(&at91ether_driver);
}

module_init(at91ether_init)
module_exit(at91ether_exit)

MODULE_LICENSE("GPL");
MODULE_DESCRIPTION("AT91RM9200 EMAC Ethernet driver");
MODULE_AUTHOR("Andrew Victor");