more cleanup

[openwrt/svn-archive/archive.git] / target / linux / atheros-2.6 / files / drivers / net / ar2313 / ar2313.c

/*
 * ar2313.c: Linux driver for the Atheros AR231x Ethernet device.
 *
 * Copyright (C) 2004 by Sameer Dekate <sdekate@arubanetworks.com>
 * Copyright (C) 2006 Imre Kaloz <kaloz@openwrt.org>
 * Copyright (C) 2006-2007 Felix Fietkau <nbd@openwrt.org>
 *
 * Thanks to Atheros for providing hardware and documentation
 * enabling me to write this driver.
 *
 * 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.
 *
 * Additional credits:
 *      This code is taken from John Taylor's Sibyte driver and then 
 *      modified for the AR2313.
 */

#include <linux/autoconf.h>
#include <linux/module.h>
#include <linux/version.h>
#include <linux/types.h>
#include <linux/errno.h>
#include <linux/ioport.h>
#include <linux/pci.h>
#include <linux/netdevice.h>
#include <linux/etherdevice.h>
#include <linux/skbuff.h>
#include <linux/init.h>
#include <linux/delay.h>
#include <linux/mm.h>
#include <linux/highmem.h>
#include <linux/sockios.h>
#include <linux/pkt_sched.h>
#include <linux/compile.h>
#include <linux/mii.h>
#include <linux/ethtool.h>
#include <linux/ctype.h>
#include <linux/platform_device.h>

#include <net/sock.h>
#include <net/ip.h>

#include <asm/system.h>
#include <asm/io.h>
#include <asm/irq.h>
#include <asm/byteorder.h>
#include <asm/uaccess.h>
#include <asm/bootinfo.h>

#define AR2313_MTU                     1692
#define AR2313_PRIOS                   1
#define AR2313_QUEUES                  (2*AR2313_PRIOS)
#define AR2313_DESCR_ENTRIES           64

#undef INDEX_DEBUG
#define DEBUG     0
#define DEBUG_TX  0
#define DEBUG_RX  0
#define DEBUG_INT 0
#define DEBUG_MC  0
#define DEBUG_ERR 1

#ifndef min
#define min(a,b)        (((a)<(b))?(a):(b))
#endif

#ifndef SMP_CACHE_BYTES
#define SMP_CACHE_BYTES L1_CACHE_BYTES
#endif

#define AR2313_MBOX_SET_BIT  0x8

#define BOARD_IDX_STATIC        0
#define BOARD_IDX_OVERFLOW      -1

#include "dma.h"
#include "ar2313.h"

/*
 * New interrupt handler strategy:
 *
 * An old interrupt handler worked using the traditional method of
 * replacing an skbuff with a new one when a packet arrives. However
 * the rx rings do not need to contain a static number of buffer
 * descriptors, thus it makes sense to move the memory allocation out
 * of the main interrupt handler and do it in a bottom half handler
 * and only allocate new buffers when the number of buffers in the
 * ring is below a certain threshold. In order to avoid starving the
 * NIC under heavy load it is however necessary to force allocation
 * when hitting a minimum threshold. The strategy for alloction is as
 * follows:
 *
 *     RX_LOW_BUF_THRES    - allocate buffers in the bottom half
 *     RX_PANIC_LOW_THRES  - we are very low on buffers, allocate
 *                           the buffers in the interrupt handler
 *     RX_RING_THRES       - maximum number of buffers in the rx ring
 *
 * One advantagous side effect of this allocation approach is that the
 * entire rx processing can be done without holding any spin lock
 * since the rx rings and registers are totally independent of the tx
 * ring and its registers.  This of course includes the kmalloc's of
 * new skb's. Thus start_xmit can run in parallel with rx processing
 * and the memory allocation on SMP systems.
 *
 * Note that running the skb reallocation in a bottom half opens up
 * another can of races which needs to be handled properly. In
 * particular it can happen that the interrupt handler tries to run
 * the reallocation while the bottom half is either running on another
 * CPU or was interrupted on the same CPU. To get around this the
 * driver uses bitops to prevent the reallocation routines from being
 * reentered.
 *
 * TX handling can also be done without holding any spin lock, wheee
 * this is fun! since tx_csm is only written to by the interrupt
 * handler.
 */

/*
 * Threshold values for RX buffer allocation - the low water marks for
 * when to start refilling the rings are set to 75% of the ring
 * sizes. It seems to make sense to refill the rings entirely from the
 * intrrupt handler once it gets below the panic threshold, that way
 * we don't risk that the refilling is moved to another CPU when the
 * one running the interrupt handler just got the slab code hot in its
 * cache.
 */
#define RX_RING_SIZE            AR2313_DESCR_ENTRIES
#define RX_PANIC_THRES          (RX_RING_SIZE/4)
#define RX_LOW_THRES            ((3*RX_RING_SIZE)/4)
#define CRC_LEN                 4
#define RX_OFFSET               2

#define AR2313_BUFSIZE          (AR2313_MTU + ETH_HLEN + CRC_LEN + RX_OFFSET)

#ifdef MODULE
MODULE_AUTHOR("Sameer Dekate <sdekate@arubanetworks.com>, Imre Kaloz <kaloz@openwrt.org>, Felix Fietkau <nbd@openwrt.org>");
MODULE_DESCRIPTION("AR2313 Ethernet driver");
#endif

#define virt_to_phys(x) ((u32)(x) & 0x1fffffff)

// prototypes
static short armiiread(struct net_device *dev, short phy, short reg);
static void armiiwrite(struct net_device *dev, short phy, short reg, short data);
#ifdef TX_TIMEOUT
static void ar2313_tx_timeout(struct net_device *dev);
#endif
static void ar2313_halt(struct net_device *dev);
static void rx_tasklet_func(unsigned long data);
static void ar2313_multicast_list(struct net_device *dev);

#ifndef ERR
#define ERR(fmt, args...) printk("%s: " fmt, __func__, ##args)
#endif


int __init ar2313_probe(struct platform_device *pdev)
{
        struct net_device *dev;
        struct ar2313_private *sp;
        struct resource *res;
        unsigned long ar_eth_base;
        char buf[64] ;

        dev = alloc_etherdev(sizeof(struct ar2313_private));

        if (dev == NULL) {
        printk(KERN_ERR "ar2313: Unable to allocate net_device structure!\n");
        return -ENOMEM;
        }

        SET_MODULE_OWNER(dev);
        platform_set_drvdata(pdev, dev);

        sp = dev->priv;
        sp->dev = dev;
        sp->cfg = pdev->dev.platform_data;

        sprintf(buf, "eth%d_membase", pdev->id);
        res = platform_get_resource_byname(pdev, IORESOURCE_MEM, buf);
        if (!res)
                return -ENODEV;
        
        sp->link = 0;
        ar_eth_base = res->start;
        sp->phy = sp->cfg->phy;

        sprintf(buf, "eth%d_irq", pdev->id);
        dev->irq = platform_get_irq_byname(pdev, buf);

        spin_lock_init(&sp->lock);

        /* initialize func pointers */
        dev->open = &ar2313_open;
        dev->stop = &ar2313_close;
        dev->hard_start_xmit = &ar2313_start_xmit;

        dev->get_stats = &ar2313_get_stats;
        dev->set_multicast_list = &ar2313_multicast_list;
#ifdef TX_TIMEOUT
        dev->tx_timeout = ar2313_tx_timeout;
        dev->watchdog_timeo = AR2313_TX_TIMEOUT;
#endif
        dev->do_ioctl = &ar2313_ioctl;

        // SAMEER: do we need this?
        dev->features |= NETIF_F_SG | NETIF_F_HIGHDMA;

        tasklet_init(&sp->rx_tasklet, rx_tasklet_func, (unsigned long) dev);
        tasklet_disable(&sp->rx_tasklet);

        sp->eth_regs = ioremap_nocache(virt_to_phys(ar_eth_base), sizeof(*sp->eth_regs));
        if (!sp->eth_regs) {
                printk("Can't remap eth registers\n");
                return(-ENXIO);
        }

        /* 
         * When there's only one MAC, PHY regs are typically on ENET0, 
         * even though the MAC might be on ENET1.
         * Needto remap PHY regs separately in this case
         */
        if (virt_to_phys(ar_eth_base) == virt_to_phys(sp->phy_regs))
                sp->phy_regs = sp->eth_regs;
        else {
                sp->phy_regs = ioremap_nocache(virt_to_phys(sp->cfg->phy_base), sizeof(*sp->phy_regs));
                if (!sp->phy_regs) {
                        printk("Can't remap phy registers\n");
                        return(-ENXIO);
                }
        }

        sp->dma_regs = ioremap_nocache(virt_to_phys(ar_eth_base + 0x1000), sizeof(*sp->dma_regs));
        dev->base_addr = (unsigned int) sp->dma_regs;
        if (!sp->dma_regs) {
                printk("Can't remap DMA registers\n");
                return(-ENXIO);
        }

        sp->int_regs = ioremap_nocache(virt_to_phys(sp->cfg->reset_base), 4);
        if (!sp->int_regs) {
                printk("Can't remap INTERRUPT registers\n");
                return(-ENXIO);
        }

        strncpy(sp->name, "Atheros AR231x", sizeof (sp->name) - 1);
        sp->name [sizeof (sp->name) - 1] = '\0';
        memcpy(dev->dev_addr, sp->cfg->macaddr, 6);
        sp->board_idx = BOARD_IDX_STATIC;

        if (ar2313_init(dev)) {
            /*
             * ar2313_init() calls ar2313_init_cleanup() on error.
             */
            kfree(dev);
            return -ENODEV;
        }

        if (register_netdev(dev)){
          printk("%s: register_netdev failed\n", __func__);
          return -1;
        }

        printk("%s: %s: %02x:%02x:%02x:%02x:%02x:%02x, irq %d\n",
               dev->name, sp->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],
               dev->irq);

        /* start link poll timer */
        ar2313_setup_timer(dev);

        return 0;
}

#if 0
static void ar2313_dump_regs(struct net_device *dev)
{
        unsigned int *ptr, i;
        struct ar2313_private *sp = (struct ar2313_private *)dev->priv;

        ptr = (unsigned int *)sp->eth_regs;
        for(i=0; i< (sizeof(ETHERNET_STRUCT)/ sizeof(unsigned int)); i++, ptr++) {
            printk("ENET: %08x = %08x\n", (int)ptr, *ptr);
        }

        ptr = (unsigned int *)sp->dma_regs;
        for(i=0; i< (sizeof(DMA)/ sizeof(unsigned int)); i++, ptr++) {
            printk("DMA: %08x = %08x\n", (int)ptr, *ptr);
        }

        ptr = (unsigned int *)sp->int_regs;
        for(i=0; i< (sizeof(INTERRUPT)/ sizeof(unsigned int)); i++, ptr++){
            printk("INT: %08x = %08x\n", (int)ptr, *ptr);
        }

        for (i = 0; i < AR2313_DESCR_ENTRIES; i++) {
        ar2313_descr_t *td = &sp->tx_ring[i];
            printk("Tx desc %2d: %08x %08x %08x %08x\n", i,
                   td->status, td->devcs, td->addr, td->descr);
        }
}
#endif

#ifdef TX_TIMEOUT
static void
ar2313_tx_timeout(struct net_device *dev)
{
        struct ar2313_private *sp = (struct ar2313_private *)dev->priv;
        unsigned long flags;
        
#if DEBUG_TX
        printk("Tx timeout\n");
#endif
        spin_lock_irqsave(&sp->lock, flags);
        ar2313_restart(dev);
        spin_unlock_irqrestore(&sp->lock, flags);
}
#endif

#if DEBUG_MC
static void
printMcList(struct net_device *dev)
{
        struct dev_mc_list *list = dev->mc_list;
        int num=0, i;
        while(list){
                printk("%d MC ADDR ", num);
                for(i=0;i<list->dmi_addrlen;i++) {
                    printk(":%02x", list->dmi_addr[i]);
                }
        list = list->next;
                printk("\n");
        }
}
#endif

/*
 * Set or clear the multicast filter for this adaptor.
 * THIS IS ABSOLUTE CRAP, disabled
 */
static void
ar2313_multicast_list(struct net_device *dev)
{   
        /* 
         * Always listen to broadcasts and 
         * treat IFF bits independently 
         */
        struct ar2313_private *sp = (struct ar2313_private *)dev->priv;
        unsigned int recognise;

        recognise = sp->eth_regs->mac_control;

        if (dev->flags & IFF_PROMISC) { /* set promiscuous mode */
                recognise |= MAC_CONTROL_PR;
        } else {
                recognise &= ~MAC_CONTROL_PR;
        }

        if ((dev->flags & IFF_ALLMULTI) || (dev->mc_count > 15)) {
#if DEBUG_MC
        printMcList(dev);
                printk("%s: all MULTICAST mc_count %d\n", __FUNCTION__, dev->mc_count);
#endif
                recognise |= MAC_CONTROL_PM;/* all multicast */
        } else if (dev->mc_count > 0) {
#if DEBUG_MC
        printMcList(dev);
                printk("%s: mc_count %d\n", __FUNCTION__, dev->mc_count);
#endif
                recognise |= MAC_CONTROL_PM; /* for the time being */
        }
#if DEBUG_MC
        printk("%s: setting %08x to %08x\n", __FUNCTION__, (int)sp->eth_regs, recognise);
#endif
        
        sp->eth_regs->mac_control = recognise;
}

static void rx_tasklet_cleanup(struct net_device *dev)
{
        struct ar2313_private *sp = dev->priv;

        /*
         * Tasklet may be scheduled. Need to get it removed from the list
         * since we're about to free the struct.
         */

        sp->unloading = 1;
        tasklet_enable(&sp->rx_tasklet);
        tasklet_kill(&sp->rx_tasklet);
}

static int __exit ar2313_remove(struct platform_device *pdev)
{
        struct net_device *dev = platform_get_drvdata(pdev);
        rx_tasklet_cleanup(dev);
        ar2313_init_cleanup(dev);
        unregister_netdev(dev);
        kfree(dev);
        return 0;
}


/*
 * Restart the AR2313 ethernet controller. 
 */
static int ar2313_restart(struct net_device *dev)
{
        /* disable interrupts */
        disable_irq(dev->irq);

        /* stop mac */
        ar2313_halt(dev);
        
        /* initialize */
        ar2313_init(dev);
        
        /* enable interrupts */
        enable_irq(dev->irq);
        
        return 0;
}

static struct platform_driver ar2313_driver = {
        .driver.name = "ar531x-eth",
        .probe = ar2313_probe,
        .remove = ar2313_remove,
};

int __init ar2313_module_init(void)
{
        return platform_driver_register(&ar2313_driver);
}

void __exit ar2313_module_cleanup(void)
{
        platform_driver_unregister(&ar2313_driver);
}

module_init(ar2313_module_init);
module_exit(ar2313_module_cleanup);


static void ar2313_free_descriptors(struct net_device *dev)
{
        struct ar2313_private *sp = dev->priv;
        if (sp->rx_ring != NULL) {
        kfree((void*)KSEG0ADDR(sp->rx_ring));
        sp->rx_ring = NULL;
        sp->tx_ring = NULL;
        }
}


static int ar2313_allocate_descriptors(struct net_device *dev)
{
        struct ar2313_private *sp = dev->priv;
        int size;
        int j;
        ar2313_descr_t *space;

        if(sp->rx_ring != NULL){
        printk("%s: already done.\n", __FUNCTION__);
        return 0;
        }

        size = (sizeof(ar2313_descr_t) * (AR2313_DESCR_ENTRIES * AR2313_QUEUES));
        space = kmalloc(size, GFP_KERNEL);
        if (space == NULL)
            return 1;

        /* invalidate caches */
        dma_cache_inv((unsigned int)space, size);

        /* now convert pointer to KSEG1 */
        space = (ar2313_descr_t *)KSEG1ADDR(space);

        memset((void *)space, 0, size);

        sp->rx_ring = space;
        space += AR2313_DESCR_ENTRIES;

        sp->tx_ring = space;
        space += AR2313_DESCR_ENTRIES;

        /* Initialize the transmit Descriptors */
        for (j = 0; j < AR2313_DESCR_ENTRIES; j++) {
        ar2313_descr_t *td = &sp->tx_ring[j];
        td->status = 0;
        td->devcs  = DMA_TX1_CHAINED;
        td->addr   = 0;
        td->descr  = virt_to_phys(&sp->tx_ring[(j+1) & (AR2313_DESCR_ENTRIES-1)]);
        }

        return 0;
}


/*
 * Generic cleanup handling data allocated during init. Used when the
 * module is unloaded or if an error occurs during initialization
 */
static void ar2313_init_cleanup(struct net_device *dev)
{
        struct ar2313_private *sp = dev->priv;
        struct sk_buff *skb;
        int j;

        ar2313_free_descriptors(dev);

        if (sp->eth_regs) iounmap((void*)sp->eth_regs);
        if (sp->dma_regs) iounmap((void*)sp->dma_regs);

        if (sp->rx_skb) {
        for (j = 0; j < AR2313_DESCR_ENTRIES; j++) {
            skb = sp->rx_skb[j];
            if (skb) {
                sp->rx_skb[j] = NULL;
                dev_kfree_skb(skb);
            }
        }
        kfree(sp->rx_skb);
        sp->rx_skb = NULL;
        }

        if (sp->tx_skb) {
        for (j = 0; j < AR2313_DESCR_ENTRIES; j++) {
            skb = sp->tx_skb[j];
            if (skb) {
                sp->tx_skb[j] = NULL;
                dev_kfree_skb(skb);
            }
        }
        kfree(sp->tx_skb);
        sp->tx_skb = NULL;
        }
}

static int ar2313_setup_timer(struct net_device *dev)
{
        struct ar2313_private *sp = dev->priv; 

        init_timer(&sp->link_timer);

        sp->link_timer.function = ar2313_link_timer_fn;
        sp->link_timer.data = (int) dev;
        sp->link_timer.expires = jiffies + HZ;

        add_timer(&sp->link_timer);
        return 0;

}

static void ar2313_link_timer_fn(unsigned long data)
{
        struct net_device *dev = (struct net_device *) data;
        struct ar2313_private *sp = dev->priv; 

        // see if the link status changed
        // This was needed to make sure we set the PHY to the
        // autonegotiated value of half or full duplex.
        ar2313_check_link(dev);
        
        // Loop faster when we don't have link. 
        // This was needed to speed up the AP bootstrap time.
        if(sp->link == 0) {
                mod_timer(&sp->link_timer, jiffies + HZ/2);
        } else {
                mod_timer(&sp->link_timer, jiffies + LINK_TIMER);
        }
}

static void ar2313_check_link(struct net_device *dev)
{
        struct ar2313_private *sp = dev->priv;
        u16 phyData;

        phyData = armiiread(dev, sp->phy, MII_BMSR);
        if (sp->phyData != phyData) {
        if (phyData & BMSR_LSTATUS) {
                /* link is present, ready link partner ability to deterine duplexity */
                int duplex = 0;
                u16 reg;

                sp->link = 1;
                reg = armiiread(dev, sp->phy, MII_BMCR);
                if (reg & BMCR_ANENABLE) {
                    /* auto neg enabled */
                    reg = armiiread(dev, sp->phy, MII_LPA);
                    duplex = (reg & (LPA_100FULL|LPA_10FULL))? 1:0;
                } else {
                    /* no auto neg, just read duplex config */
                    duplex = (reg & BMCR_FULLDPLX)? 1:0;
                }

                printk(KERN_INFO "%s: Configuring MAC for %s duplex\n", dev->name,
                       (duplex)? "full":"half");

                if (duplex) {
                    /* full duplex */
                    sp->eth_regs->mac_control = ((sp->eth_regs->mac_control | MAC_CONTROL_F) &
                                                 ~MAC_CONTROL_DRO);
                } else {
                    /* half duplex */
                    sp->eth_regs->mac_control = ((sp->eth_regs->mac_control | MAC_CONTROL_DRO) &
                                                 ~MAC_CONTROL_F);
                }
                } else {
                /* no link */
                sp->link = 0;
                }
            sp->phyData = phyData;
        }
}
  
static int
ar2313_reset_reg(struct net_device *dev)
{
        struct ar2313_private *sp = (struct ar2313_private *)dev->priv;
        unsigned int ethsal, ethsah;
        unsigned int flags;

        *sp->int_regs |= sp->cfg->reset_mac;
        mdelay(10);
        *sp->int_regs &= ~sp->cfg->reset_mac;
        mdelay(10);
        *sp->int_regs |= sp->cfg->reset_phy;
        mdelay(10);
        *sp->int_regs &= ~sp->cfg->reset_phy;
        mdelay(10);

        sp->dma_regs->bus_mode = (DMA_BUS_MODE_SWR);
        mdelay(10);
        sp->dma_regs->bus_mode = ((32 << DMA_BUS_MODE_PBL_SHIFT) | DMA_BUS_MODE_BLE);

        /* enable interrupts */
        sp->dma_regs->intr_ena = (DMA_STATUS_AIS |
                              DMA_STATUS_NIS |
                              DMA_STATUS_RI  |
                              DMA_STATUS_TI  |
                              DMA_STATUS_FBE);
        sp->dma_regs->xmt_base = virt_to_phys(sp->tx_ring);
        sp->dma_regs->rcv_base = virt_to_phys(sp->rx_ring);
        sp->dma_regs->control = (DMA_CONTROL_SR | DMA_CONTROL_ST | DMA_CONTROL_SF);
        
        sp->eth_regs->flow_control = (FLOW_CONTROL_FCE);
        sp->eth_regs->vlan_tag = (0x8100);

        /* Enable Ethernet Interface */
        flags = (MAC_CONTROL_TE  | /* transmit enable */
             MAC_CONTROL_PM  | /* pass mcast */
             MAC_CONTROL_F   | /* full duplex */
             MAC_CONTROL_HBD); /* heart beat disabled */

        if (dev->flags & IFF_PROMISC) { /* set promiscuous mode */
        flags |= MAC_CONTROL_PR;
        }
        sp->eth_regs->mac_control = flags;

        /* Set all Ethernet station address registers to their initial values */
        ethsah = ((((u_int)(dev->dev_addr[5]) << 8) & (u_int)0x0000FF00) |
              (((u_int)(dev->dev_addr[4]) << 0) & (u_int)0x000000FF));

        ethsal = ((((u_int)(dev->dev_addr[3]) << 24) & (u_int)0xFF000000) |
                  (((u_int)(dev->dev_addr[2]) << 16) & (u_int)0x00FF0000) |
                  (((u_int)(dev->dev_addr[1]) <<  8) & (u_int)0x0000FF00) |
                  (((u_int)(dev->dev_addr[0]) <<  0) & (u_int)0x000000FF) );

        sp->eth_regs->mac_addr[0] = ethsah;
        sp->eth_regs->mac_addr[1] = ethsal;

        mdelay(10);

        return(0);
}


static int ar2313_init(struct net_device *dev)
{
        struct ar2313_private *sp = dev->priv;
        int ecode=0;

        /*
         * Allocate descriptors
         */
        if (ar2313_allocate_descriptors(dev)) {
        printk("%s: %s: ar2313_allocate_descriptors failed\n", 
                        dev->name, __FUNCTION__);
        ecode = -EAGAIN;
            goto init_error;
        }

        /*
         * Get the memory for the skb rings.
         */
        if(sp->rx_skb == NULL) {
        sp->rx_skb = kmalloc(sizeof(struct sk_buff *) * AR2313_DESCR_ENTRIES, GFP_KERNEL);
        if (!(sp->rx_skb)) {
            printk("%s: %s: rx_skb kmalloc failed\n", 
                            dev->name, __FUNCTION__);
            ecode = -EAGAIN;
            goto init_error;
        }
        }
        memset(sp->rx_skb, 0, sizeof(struct sk_buff *) * AR2313_DESCR_ENTRIES);

        if(sp->tx_skb == NULL) {
        sp->tx_skb = kmalloc(sizeof(struct sk_buff *) * AR2313_DESCR_ENTRIES, GFP_KERNEL);
        if (!(sp->tx_skb)) {
            printk("%s: %s: tx_skb kmalloc failed\n", 
                            dev->name, __FUNCTION__);
            ecode = -EAGAIN;
            goto init_error;
        }
        }
        memset(sp->tx_skb, 0, sizeof(struct sk_buff *) * AR2313_DESCR_ENTRIES);

        /*
         * Set tx_csm before we start receiving interrupts, otherwise
         * the interrupt handler might think it is supposed to process
         * tx ints before we are up and running, which may cause a null
         * pointer access in the int handler.
         */
        sp->rx_skbprd = 0;
        sp->cur_rx = 0;
        sp->tx_prd = 0;
        sp->tx_csm = 0;

        /*
         * Zero the stats before starting the interface
         */
        memset(&sp->stats, 0, sizeof(sp->stats));

        /*
         * We load the ring here as there seem to be no way to tell the
         * firmware to wipe the ring without re-initializing it.
         */
        ar2313_load_rx_ring(dev, RX_RING_SIZE);

        /* 
         * Init hardware
         */
        ar2313_reset_reg(dev);

        /*
         * Get the IRQ
         */
        ecode = request_irq(dev->irq, &ar2313_interrupt, IRQF_SHARED | IRQF_DISABLED | IRQF_SAMPLE_RANDOM, dev->name, dev);
        if (ecode) {
            printk(KERN_WARNING "%s: %s: Requested IRQ %d is busy\n",
               dev->name, __FUNCTION__, dev->irq);
        goto init_error;
        }


        tasklet_enable(&sp->rx_tasklet);

        return 0;

 init_error:
        ar2313_init_cleanup(dev);
        return ecode;
}

/*
 * Load the rx ring.
 *
 * Loading rings is safe without holding the spin lock since this is
 * done only before the device is enabled, thus no interrupts are
 * generated and by the interrupt handler/tasklet handler.
 */
static void ar2313_load_rx_ring(struct net_device *dev, int nr_bufs)
{

        struct ar2313_private *sp = ((struct net_device *)dev)->priv;
        short i, idx;

        idx = sp->rx_skbprd;

        for (i = 0; i < nr_bufs; i++) {
            struct sk_buff *skb;
        ar2313_descr_t *rd;

        if (sp->rx_skb[idx]) {
#if DEBUG_RX
            printk(KERN_INFO "ar2313 rx refill full\n");
#endif /* DEBUG */
            break;
        }

            // partha: create additional room for the second GRE fragment
        skb = alloc_skb(AR2313_BUFSIZE+128, GFP_ATOMIC);
        if (!skb) {
            printk("\n\n\n\n %s: No memory in system\n\n\n\n", __FUNCTION__);
            break;
        }
            // partha: create additional room in the front for tx pkt capture
            skb_reserve(skb, 32);

        /*
         * Make sure IP header starts on a fresh cache line.
         */
        skb->dev = dev;
        skb_reserve(skb, RX_OFFSET);
        sp->rx_skb[idx] = skb;

        rd = (ar2313_descr_t *) &sp->rx_ring[idx];

        /* initialize dma descriptor */
        rd->devcs  = ((AR2313_BUFSIZE << DMA_RX1_BSIZE_SHIFT) |
                          DMA_RX1_CHAINED);
        rd->addr   = virt_to_phys(skb->data);
        rd->descr  = virt_to_phys(&sp->rx_ring[(idx+1) & (AR2313_DESCR_ENTRIES-1)]);
        rd->status = DMA_RX_OWN;

        idx = DSC_NEXT(idx);
        }

        if (!i) {
#if DEBUG_ERR
            printk(KERN_INFO "Out of memory when allocating standard receive buffers\n");
#endif /* DEBUG */
        } else {
        sp->rx_skbprd = idx;
        }

        return;
}

#define AR2313_MAX_PKTS_PER_CALL        64

static int ar2313_rx_int(struct net_device *dev)
{
        struct ar2313_private *sp = dev->priv;
        struct sk_buff *skb, *skb_new;
        ar2313_descr_t *rxdesc;
        unsigned int status;
        u32 idx;
        int pkts = 0;
        int rval;

        idx = sp->cur_rx;

        /* process at most the entire ring and then wait for another interrupt */
        while(1) {

        rxdesc = &sp->rx_ring[idx];
        status = rxdesc->status;
        if (status & DMA_RX_OWN) {
            /* SiByte owns descriptor or descr not yet filled in */
                rval = 0;
            break;
        }

            if (++pkts > AR2313_MAX_PKTS_PER_CALL) {
                rval = 1;
                break;
            }

#if DEBUG_RX
        printk("index %d\n", idx);
        printk("RX status %08x\n", rxdesc->status);
        printk("RX devcs  %08x\n", rxdesc->devcs );
        printk("RX addr   %08x\n", rxdesc->addr  );
        printk("RX descr  %08x\n", rxdesc->descr );
#endif

            if ((status & (DMA_RX_ERROR|DMA_RX_ERR_LENGTH)) &&
            (!(status & DMA_RX_LONG))){
#if DEBUG_RX
            printk("%s: rx ERROR %08x\n", __FUNCTION__, status);
#endif
            sp->stats.rx_errors++;
            sp->stats.rx_dropped++;

            /* add statistics counters */
            if (status & DMA_RX_ERR_CRC)    sp->stats.rx_crc_errors++;
            if (status & DMA_RX_ERR_COL)    sp->stats.rx_over_errors++;
            if (status & DMA_RX_ERR_LENGTH)
                    sp->stats.rx_length_errors++;
            if (status & DMA_RX_ERR_RUNT)   sp->stats.rx_over_errors++;
            if (status & DMA_RX_ERR_DESC)   sp->stats.rx_over_errors++;

        } else {
            /* alloc new buffer. */
            skb_new = dev_alloc_skb(AR2313_BUFSIZE + RX_OFFSET + 128);
            if (skb_new != NULL) {

                skb = sp->rx_skb[idx];
                /* set skb */
                skb_put(skb, ((status >> DMA_RX_LEN_SHIFT) & 0x3fff) - CRC_LEN);

                sp->stats.rx_bytes += skb->len;
                skb->protocol = eth_type_trans(skb, dev);
                /* pass the packet to upper layers */
                netif_rx(skb);

                skb_new->dev = dev;
                /* 16 bit align */
                skb_reserve(skb_new, RX_OFFSET+32);
                /* reset descriptor's curr_addr */
                rxdesc->addr = virt_to_phys(skb_new->data); 

                sp->stats.rx_packets++;
                sp->rx_skb[idx] = skb_new;
            } else {
                        sp->stats.rx_dropped++;
            }
        }

        rxdesc->devcs = ((AR2313_BUFSIZE << DMA_RX1_BSIZE_SHIFT) | 
                             DMA_RX1_CHAINED);
        rxdesc->status = DMA_RX_OWN;

        idx = DSC_NEXT(idx);
        }

        sp->cur_rx = idx;

        return rval;
}


static void ar2313_tx_int(struct net_device *dev)
{
        struct ar2313_private *sp = dev->priv;
        u32 idx;
        struct sk_buff *skb;
        ar2313_descr_t *txdesc;
        unsigned int status=0;

        idx = sp->tx_csm;

        while (idx != sp->tx_prd) {

        txdesc = &sp->tx_ring[idx];

#if DEBUG_TX
        printk("%s: TXINT: csm=%d idx=%d prd=%d status=%x devcs=%x addr=%08x descr=%x\n", 
                dev->name, sp->tx_csm, idx, sp->tx_prd,
                txdesc->status, txdesc->devcs, txdesc->addr, txdesc->descr);
#endif /* DEBUG */

        if ((status = txdesc->status) & DMA_TX_OWN) {
            /* ar2313 dma still owns descr */
            break;
        }
        /* done with this descriptor */
        dma_unmap_single(NULL, txdesc->addr, txdesc->devcs & DMA_TX1_BSIZE_MASK, DMA_TO_DEVICE);
        txdesc->status = 0;

        if (status & DMA_TX_ERROR){
                sp->stats.tx_errors++;
                sp->stats.tx_dropped++;
                if(status & DMA_TX_ERR_UNDER)
                        sp->stats.tx_fifo_errors++;
                if(status & DMA_TX_ERR_HB)
                        sp->stats.tx_heartbeat_errors++;
                if(status & (DMA_TX_ERR_LOSS |
                                 DMA_TX_ERR_LINK))
                        sp->stats.tx_carrier_errors++;
                    if (status & (DMA_TX_ERR_LATE|
                                  DMA_TX_ERR_COL |
                                  DMA_TX_ERR_JABBER |
                                  DMA_TX_ERR_DEFER))
                        sp->stats.tx_aborted_errors++;
        } else {
                /* transmit OK */
                sp->stats.tx_packets++;
        }

        skb = sp->tx_skb[idx];
        sp->tx_skb[idx] = NULL;
        idx = DSC_NEXT(idx);
        sp->stats.tx_bytes += skb->len;
        dev_kfree_skb_irq(skb);
        }

        sp->tx_csm = idx;

        return;
}


static void
rx_tasklet_func(unsigned long data)
{
        struct net_device *dev = (struct net_device *) data;
        struct ar2313_private *sp = dev->priv;

        if (sp->unloading) {
            return;
        }

            if (ar2313_rx_int(dev)) {
                tasklet_hi_schedule(&sp->rx_tasklet);
            }
            else {
                unsigned long flags;
                spin_lock_irqsave(&sp->lock, flags);
                sp->dma_regs->intr_ena |= DMA_STATUS_RI;
                spin_unlock_irqrestore(&sp->lock, flags);
            }
}

static void
rx_schedule(struct net_device *dev)
{
        struct ar2313_private *sp = dev->priv;

        sp->dma_regs->intr_ena &= ~DMA_STATUS_RI;

        tasklet_hi_schedule(&sp->rx_tasklet);
}

static irqreturn_t ar2313_interrupt(int irq, void *dev_id)
{
        struct net_device *dev = (struct net_device *)dev_id;
        struct ar2313_private *sp = dev->priv;
        unsigned int status, enabled;

        /* clear interrupt */
        /*
         * Don't clear RI bit if currently disabled.
         */
        status = sp->dma_regs->status;
        enabled = sp->dma_regs->intr_ena;
        sp->dma_regs->status = status & enabled;

        if (status & DMA_STATUS_NIS) {
        /* normal status */
            /*
             * Don't schedule rx processing if interrupt
             * is already disabled.
             */
        if (status & enabled & DMA_STATUS_RI) {
            /* receive interrupt */
            rx_schedule(dev);
        }
        if (status & DMA_STATUS_TI) {
           /* transmit interrupt */
            ar2313_tx_int(dev);
        }
        }

        if (status & DMA_STATUS_AIS) {
#if DEBUG_INT
            printk("%s: AIS set %08x & %x\n", __FUNCTION__,
                   status, (DMA_STATUS_FBE | DMA_STATUS_TPS));
#endif
        /* abnormal status */
        if (status & (DMA_STATUS_FBE | DMA_STATUS_TPS)) {
            ar2313_restart(dev);
        }
        }
        return IRQ_HANDLED;
}


static int ar2313_open(struct net_device *dev)
{
        struct ar2313_private *sp;

        sp = dev->priv;

        dev->mtu = 1500;
        netif_start_queue(dev);

        sp->eth_regs->mac_control |= MAC_CONTROL_RE;

        return 0;
}

static void ar2313_halt(struct net_device *dev)
{
        struct ar2313_private *sp = dev->priv;
        int j;

        tasklet_disable(&sp->rx_tasklet);

        /* kill the MAC */
        sp->eth_regs->mac_control &= ~(MAC_CONTROL_RE | /* disable Receives */
                                       MAC_CONTROL_TE); /* disable Transmits */
        /* stop dma */
        sp->dma_regs->control = 0;
        sp->dma_regs->bus_mode = DMA_BUS_MODE_SWR;

        /* place phy and MAC in reset */
        *sp->int_regs |= (sp->cfg->reset_mac | sp->cfg->reset_phy);

        /* free buffers on tx ring */
        for (j = 0; j < AR2313_DESCR_ENTRIES; j++) {
        struct sk_buff *skb;
        ar2313_descr_t *txdesc;

        txdesc = &sp->tx_ring[j];
        txdesc->descr = 0;

        skb = sp->tx_skb[j];
        if (skb) {
            dev_kfree_skb(skb);
            sp->tx_skb[j] = NULL;
        }
        }
}

/*
 * close should do nothing. Here's why. It's called when
 * 'ifconfig bond0 down' is run. If it calls free_irq then
 * the irq is gone forever ! When bond0 is made 'up' again,
 * the ar2313_open () does not call request_irq (). Worse,
 * the call to ar2313_halt() generates a WDOG reset due to
 * the write to 'sp->int_regs' and the box reboots.
 * Commenting this out is good since it allows the
 * system to resume when bond0 is made up again.
 */
static int ar2313_close(struct net_device *dev)
{
#if 0
        /*
         * Disable interrupts
         */
        disable_irq(dev->irq);
                
        /*
         * Without (or before) releasing irq and stopping hardware, this
         * is an absolute non-sense, by the way. It will be reset instantly
         * by the first irq.
         */
        netif_stop_queue(dev);

        /* stop the MAC and DMA engines */
        ar2313_halt(dev);

        /* release the interrupt */
        free_irq(dev->irq, dev);

#endif
        return 0;
}

static int ar2313_start_xmit(struct sk_buff *skb, struct net_device *dev)
{
        struct ar2313_private *sp = dev->priv;
        ar2313_descr_t *td;
        u32 idx;

        idx = sp->tx_prd;
        td = &sp->tx_ring[idx];

        if (td->status & DMA_TX_OWN) {
#if DEBUG_TX
        printk("%s: No space left to Tx\n", __FUNCTION__);
#endif
            /* free skbuf and lie to the caller that we sent it out */
            sp->stats.tx_dropped++;
        dev_kfree_skb(skb);

            /* restart transmitter in case locked */
            sp->dma_regs->xmt_poll = 0;
        return 0;
        }

        /* Setup the transmit descriptor. */
        td->devcs = ((skb->len << DMA_TX1_BSIZE_SHIFT) | 
                     (DMA_TX1_LS|DMA_TX1_IC|DMA_TX1_CHAINED));
        td->addr = dma_map_single(NULL, skb->data, skb->len, DMA_TO_DEVICE);
        td->status = DMA_TX_OWN;

        /* kick transmitter last */
        sp->dma_regs->xmt_poll = 0;

#if DEBUG_TX
        printk("index %d\n", idx);
        printk("TX status %08x\n", td->status);
        printk("TX devcs  %08x\n", td->devcs );
        printk("TX addr   %08x\n", td->addr  );
        printk("TX descr  %08x\n", td->descr );
#endif

        sp->tx_skb[idx] = skb;
        idx = DSC_NEXT(idx);
        sp->tx_prd = idx;

        return 0;
}

static int netdev_get_ecmd(struct net_device *dev, struct ethtool_cmd *ecmd)
{
        struct ar2313_private *np = dev->priv;
        u32 tmp;

        ecmd->supported = 
                (SUPPORTED_10baseT_Half | SUPPORTED_10baseT_Full |
                SUPPORTED_100baseT_Half | SUPPORTED_100baseT_Full |
                SUPPORTED_Autoneg | SUPPORTED_TP | SUPPORTED_MII);
        
            ecmd->port = PORT_TP;
        /* only supports internal transceiver */
        ecmd->transceiver = XCVR_INTERNAL;
        /* not sure what this is for */
        ecmd->phy_address = 1;

        ecmd->advertising = ADVERTISED_MII;
        tmp = armiiread(dev, np->phy, MII_ADVERTISE);
        if (tmp & ADVERTISE_10HALF)
                ecmd->advertising |= ADVERTISED_10baseT_Half;
        if (tmp & ADVERTISE_10FULL)
                ecmd->advertising |= ADVERTISED_10baseT_Full;
        if (tmp & ADVERTISE_100HALF)
                ecmd->advertising |= ADVERTISED_100baseT_Half;
        if (tmp & ADVERTISE_100FULL)
                ecmd->advertising |= ADVERTISED_100baseT_Full;

        tmp = armiiread(dev, np->phy, MII_BMCR);
        if (tmp & BMCR_ANENABLE) {
                ecmd->advertising |= ADVERTISED_Autoneg;
                ecmd->autoneg = AUTONEG_ENABLE;
        } else {
                ecmd->autoneg = AUTONEG_DISABLE;
        }

            if (ecmd->autoneg == AUTONEG_ENABLE) {
                tmp = armiiread(dev, np->phy, MII_LPA);
                if (tmp & (LPA_100FULL|LPA_10FULL)) {
                    ecmd->duplex = DUPLEX_FULL;
                } else {
                    ecmd->duplex = DUPLEX_HALF;
                }
                if (tmp & (LPA_100FULL|LPA_100HALF)) {
                ecmd->speed = SPEED_100;
                } else {
                ecmd->speed = SPEED_10;
                }
            } else {
                if (tmp & BMCR_FULLDPLX) {
                    ecmd->duplex = DUPLEX_FULL;
                } else {
                    ecmd->duplex = DUPLEX_HALF;
                }
                if (tmp & BMCR_SPEED100) {
                ecmd->speed = SPEED_100;
                } else {
                ecmd->speed = SPEED_10;
                }
        }

        /* ignore maxtxpkt, maxrxpkt for now */

        return 0;
}

static int netdev_set_ecmd(struct net_device *dev, struct ethtool_cmd *ecmd)
{
        struct ar2313_private *np = dev->priv;
        u32 tmp;

        if (ecmd->speed != SPEED_10 && ecmd->speed != SPEED_100)
                return -EINVAL;
        if (ecmd->duplex != DUPLEX_HALF && ecmd->duplex != DUPLEX_FULL)
                return -EINVAL;
        if (ecmd->port != PORT_TP)
                return -EINVAL;
        if (ecmd->transceiver != XCVR_INTERNAL)
                return -EINVAL;
        if (ecmd->autoneg != AUTONEG_DISABLE && ecmd->autoneg != AUTONEG_ENABLE)
                return -EINVAL;
        /* ignore phy_address, maxtxpkt, maxrxpkt for now */
        
        /* WHEW! now lets bang some bits */
        
        tmp = armiiread(dev, np->phy, MII_BMCR);
        if (ecmd->autoneg == AUTONEG_ENABLE) {
                /* turn on autonegotiation */
                tmp |= BMCR_ANENABLE;
                    printk("%s: Enabling auto-neg\n", dev->name);
        } else {
                /* turn off auto negotiation, set speed and duplexity */
                tmp &= ~(BMCR_ANENABLE | BMCR_SPEED100 | BMCR_FULLDPLX);
                if (ecmd->speed == SPEED_100)
                        tmp |= BMCR_SPEED100;
                if (ecmd->duplex == DUPLEX_FULL)
                        tmp |= BMCR_FULLDPLX;
                    printk("%s: Hard coding %d/%s\n", dev->name, 
                           (ecmd->speed == SPEED_100)? 100:10,
                           (ecmd->duplex == DUPLEX_FULL)? "full":"half");
        }
        armiiwrite(dev, np->phy, MII_BMCR, tmp);
            np->phyData = 0;
        return 0;
}

static int netdev_ethtool_ioctl(struct net_device *dev, void *useraddr)
{
        struct ar2313_private *np = dev->priv;
        u32 cmd;
        
        if (get_user(cmd, (u32 *)useraddr))
                return -EFAULT;

            switch (cmd) {
        /* get settings */
        case ETHTOOL_GSET: {
                struct ethtool_cmd ecmd = { ETHTOOL_GSET };
                spin_lock_irq(&np->lock);
                netdev_get_ecmd(dev, &ecmd);
                spin_unlock_irq(&np->lock);
                if (copy_to_user(useraddr, &ecmd, sizeof(ecmd)))
                        return -EFAULT;
                return 0;
        }
        /* set settings */
        case ETHTOOL_SSET: {
                struct ethtool_cmd ecmd;
                int r;
                if (copy_from_user(&ecmd, useraddr, sizeof(ecmd)))
                        return -EFAULT;
                spin_lock_irq(&np->lock);
                r = netdev_set_ecmd(dev, &ecmd);
                spin_unlock_irq(&np->lock);
                return r;
        }
        /* restart autonegotiation */
        case ETHTOOL_NWAY_RST: {
                int tmp;
                int r = -EINVAL;
                /* if autoneg is off, it's an error */
                tmp = armiiread(dev, np->phy, MII_BMCR);
                if (tmp & BMCR_ANENABLE) {
                        tmp |= (BMCR_ANRESTART);
                        armiiwrite(dev, np->phy, MII_BMCR, tmp);
                        r = 0;
                }
                return r;
        }
        /* get link status */
        case ETHTOOL_GLINK: {
                struct ethtool_value edata = {ETHTOOL_GLINK};
                edata.data = (armiiread(dev, np->phy, MII_BMSR)&BMSR_LSTATUS) ? 1:0;
                if (copy_to_user(useraddr, &edata, sizeof(edata)))
                        return -EFAULT;
                return 0;
        }
            }
        
        return -EOPNOTSUPP;
}

static int ar2313_ioctl(struct net_device *dev, struct ifreq *ifr, int cmd)
{
        struct mii_ioctl_data *data = (struct mii_ioctl_data *)&ifr->ifr_data;

        switch (cmd) {
          
        case SIOCETHTOOL:
            return netdev_ethtool_ioctl(dev, (void *) ifr->ifr_data);

        case SIOCGMIIPHY:               /* Get address of MII PHY in use. */
            data->phy_id = 1;
            /* Fall Through */

        case SIOCGMIIREG:               /* Read MII PHY register. */
            data->val_out = armiiread(dev, data->phy_id & 0x1f, 
                                      data->reg_num & 0x1f);
            return 0;
        case SIOCSMIIREG:               /* Write MII PHY register. */
            if (!capable(CAP_NET_ADMIN))
                return -EPERM;
            armiiwrite(dev, data->phy_id & 0x1f, 
                       data->reg_num & 0x1f, data->val_in);
            return 0;

        case SIOCSIFHWADDR:
            if (copy_from_user(dev->dev_addr, ifr->ifr_data, sizeof(dev->dev_addr)))
                return -EFAULT;
            return 0;

        case SIOCGIFHWADDR:
            if (copy_to_user(ifr->ifr_data, dev->dev_addr, sizeof(dev->dev_addr)))
                return -EFAULT;
            return 0;

        default:
            break;
        }

        return -EOPNOTSUPP;
}

static struct net_device_stats *ar2313_get_stats(struct net_device *dev)
{
  struct ar2313_private *sp = dev->priv;
        return &sp->stats;
}


#define MII_ADDR(phy, reg) \
        ((reg << MII_ADDR_REG_SHIFT) | (phy << MII_ADDR_PHY_SHIFT))

static short
armiiread(struct net_device *dev, short phy, short reg)
{
        struct ar2313_private *sp = (struct ar2313_private *)dev->priv;
        volatile ETHERNET_STRUCT *ethernet = sp->phy_regs;

        ethernet->mii_addr = MII_ADDR(phy, reg);
        while (ethernet->mii_addr & MII_ADDR_BUSY);
        return (ethernet->mii_data >> MII_DATA_SHIFT);
}

static void
armiiwrite(struct net_device *dev, short phy, short reg, short data)
{
        struct ar2313_private *sp = (struct ar2313_private *)dev->priv;
        volatile ETHERNET_STRUCT *ethernet = sp->phy_regs;

        while (ethernet->mii_addr & MII_ADDR_BUSY);
        ethernet->mii_data = data << MII_DATA_SHIFT;
        ethernet->mii_addr = MII_ADDR(phy, reg) | MII_ADDR_WRITE;
}