converted atheros ethernet driver to phy layer

[openwrt/svn-archive/archive.git] / target / linux / atheros / 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/phy.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_LICENSE("GPL");
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
#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 rx_tasklet_cleanup(struct net_device *dev);
static void ar2313_multicast_list(struct net_device *dev);

static int mdiobus_read(struct mii_bus *bus, int phy_addr, int regnum);
static int mdiobus_write(struct mii_bus *bus, int phy_addr, int regnum, u16 value);
static int mdiobus_reset(struct mii_bus *bus);
static int mdiobus_probe (struct net_device *dev);
static void ar2313_adjust_link(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);

        sp->mii_bus.priv = dev;
        sp->mii_bus.read = mdiobus_read;
        sp->mii_bus.write = mdiobus_write;
        sp->mii_bus.reset = mdiobus_reset;
        sp->mii_bus.name = "ar2313_eth_mii";
        sp->mii_bus.id = 0;
        sp->mii_bus.irq = kmalloc(sizeof(int), GFP_KERNEL);
        *sp->mii_bus.irq = PHY_POLL;
        
        mdiobus_register(&sp->mii_bus);

        if (mdiobus_probe(dev) != 0) {
                printk(KERN_ERR "ar2313: mdiobus_probe failed");
                rx_tasklet_cleanup(dev);
                ar2313_init_cleanup(dev);
                unregister_netdev(dev);
                kfree(dev);
        } else {
                /* 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 = mdiobus_read(&sp->mii_bus, 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 = mdiobus_read(&sp->mii_bus, sp->phy, MII_BMCR);
                        if (reg & BMCR_ANENABLE) {
                                /* auto neg enabled */
                                reg = mdiobus_read(&sp->mii_bus, 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 ar2313_ioctl(struct net_device *dev, struct ifreq *ifr, int cmd)
{
        struct mii_ioctl_data *data = (struct mii_ioctl_data *) &ifr->ifr_data;
        struct ar2313_private *sp = dev->priv;
        int ret;
        
        switch (cmd) {

        case SIOCETHTOOL:
                spin_lock_irq(&sp->lock);
                ret = phy_ethtool_ioctl(sp->phy_dev, (void *) ifr->ifr_data);
                spin_unlock_irq(&sp->lock);
                return ret;

        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;
        
        case SIOCGMIIPHY:
        case SIOCGMIIREG:
        case SIOCSMIIREG:
                return phy_mii_ioctl(sp->phy_dev, data, cmd);
        
        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;
}


static void ar2313_adjust_link(struct net_device *dev)
{
        printk(KERN_ERR " ar2313_adjust_link implementation missing\n");
}

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

static int 
mdiobus_read(struct mii_bus *bus, int phy_addr, int regnum)
{
        struct net_device *const dev = bus->priv;
        struct ar2313_private *sp = (struct ar2313_private *) dev->priv;
        volatile ETHERNET_STRUCT *ethernet = sp->phy_regs;

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

static int 
mdiobus_write(struct mii_bus *bus, int phy_addr, int regnum,
             u16 value)
{
        struct net_device *const dev = bus->priv;
        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 = value << MII_DATA_SHIFT;
        ethernet->mii_addr = MII_ADDR(phy_addr, regnum) | MII_ADDR_WRITE;

        return 0;
}

static int mdiobus_reset(struct mii_bus *bus)
{
        struct net_device *const dev = bus->priv;

        ar2313_reset_reg(dev);
        
        return 0;
}

static int mdiobus_probe (struct net_device *dev)
{
        struct ar2313_private *const sp = (struct ar2313_private *) dev->priv;
        struct phy_device *phydev = NULL;
        int phy_addr;

        /* find the first (lowest address) PHY on the current MAC's MII bus */
        for (phy_addr = 0; phy_addr < PHY_MAX_ADDR; phy_addr++)
                if (sp->mii_bus.phy_map[phy_addr]) {
                        phydev = sp->mii_bus.phy_map[phy_addr];
                        break; /* break out with first one found */
                }
        
        if (!phydev) {
                printk (KERN_ERR "ar2313:%s: no PHY found\n", dev->name);
                return -1;
        }
        
        /* now we are supposed to have a proper phydev, to attach to... */
        BUG_ON(!phydev);
        BUG_ON(phydev->attached_dev);
        
        phydev = phy_connect(dev, phydev->dev.bus_id, &ar2313_adjust_link, 0,
                PHY_INTERFACE_MODE_MII);
        
        if (IS_ERR(phydev)) {
                printk(KERN_ERR "%s: Could not attach to PHY\n", dev->name);
                return PTR_ERR(phydev);
        }

        /* mask with MAC supported features */
        phydev->supported &= (SUPPORTED_10baseT_Half
                | SUPPORTED_10baseT_Full
                | SUPPORTED_100baseT_Half
                | SUPPORTED_100baseT_Full
                | SUPPORTED_Autoneg
                /* | SUPPORTED_Pause | SUPPORTED_Asym_Pause */
                | SUPPORTED_MII
                | SUPPORTED_TP);
        
        phydev->advertising = phydev->supported;
        
        //sp->old_link = 0;
        //sp->old_speed = 0;
        //sp->old_duplex = -1;
        sp->phy_dev = phydev;
        
        printk(KERN_INFO "%s: attached PHY driver [%s] "
                "(mii_bus:phy_addr=%s)\n",
                dev->name, phydev->drv->name, phydev->dev.bus_id);
        
        return 0;
}