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[hh.org.git] / drivers / net / dm9000.c

/*
 *   dm9000.c: Version 1.2 03/18/2003
 *
 *         A Davicom DM9000 ISA NIC fast Ethernet driver for Linux.
 *      Copyright (C) 1997  Sten Wang
 *
 *      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.
 *
 *      This program is distributed in the hope that it will be useful,
 *      but WITHOUT ANY WARRANTY; without even the implied warranty of
 *      MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 *      GNU General Public License for more details.
 *
 *   (C)Copyright 1997-1998 DAVICOM Semiconductor,Inc. All Rights Reserved.
 *
 * V0.11        06/20/2001      REG_0A bit3=1, default enable BP with DA match
 *      06/22/2001      Support DM9801 progrmming
 *                      E3: R25 = ((R24 + NF) & 0x00ff) | 0xf000
 *                      E4: R25 = ((R24 + NF) & 0x00ff) | 0xc200
 *                              R17 = (R17 & 0xfff0) | NF + 3
 *                      E5: R25 = ((R24 + NF - 3) & 0x00ff) | 0xc200
 *                              R17 = (R17 & 0xfff0) | NF
 *
 * v1.00                modify by simon 2001.9.5
 *                         change for kernel 2.4.x
 *
 * v1.1   11/09/2001            fix force mode bug
 *
 * v1.2   03/18/2003       Weilun Huang <weilun_huang@davicom.com.tw>:
 *                      Fixed phy reset.
 *                      Added tx/rx 32 bit mode.
 *                      Cleaned up for kernel merge.
 *
 *        03/03/2004    Sascha Hauer <s.hauer@pengutronix.de>
 *                      Port to 2.6 kernel
 *
 *        24-Sep-2004   Ben Dooks <ben@simtec.co.uk>
 *                      Cleanup of code to remove ifdefs
 *                      Allowed platform device data to influence access width
 *                      Reformatting areas of code
 *
 *        17-Mar-2005   Sascha Hauer <s.hauer@pengutronix.de>
 *                      * removed 2.4 style module parameters
 *                      * removed removed unused stat counter and fixed
 *                        net_device_stats
 *                      * introduced tx_timeout function
 *                      * reworked locking
 *
 *        01-Jul-2005   Ben Dooks <ben@simtec.co.uk>
 *                      * fixed spinlock call without pointer
 *                      * ensure spinlock is initialised
 */

#include <linux/module.h>
#include <linux/ioport.h>
#include <linux/netdevice.h>
#include <linux/etherdevice.h>
#include <linux/init.h>
#include <linux/skbuff.h>
#include <linux/spinlock.h>
#include <linux/crc32.h>
#include <linux/mii.h>
#include <linux/dm9000.h>
#include <linux/delay.h>
#include <linux/platform_device.h>

#include <asm/delay.h>
#include <asm/irq.h>
#include <asm/io.h>

#include "dm9000.h"

/* Board/System/Debug information/definition ---------------- */

#define DM9000_PHY              0x40    /* PHY address 0x01 */

#define TRUE                    1
#define FALSE                   0

#define CARDNAME "dm9000"
#define PFX CARDNAME ": "

#define DM9000_TIMER_WUT  jiffies+(HZ*2)        /* timer wakeup time : 2 second */

#define DM9000_DEBUG 0

#if DM9000_DEBUG > 2
#define PRINTK3(args...)  printk(CARDNAME ": " args)
#else
#define PRINTK3(args...)  do { } while(0)
#endif

#if DM9000_DEBUG > 1
#define PRINTK2(args...)  printk(CARDNAME ": " args)
#else
#define PRINTK2(args...)  do { } while(0)
#endif

#if DM9000_DEBUG > 0
#define PRINTK1(args...)  printk(CARDNAME ": " args)
#define PRINTK(args...)   printk(CARDNAME ": " args)
#else
#define PRINTK1(args...)  do { } while(0)
#define PRINTK(args...)   printk(KERN_DEBUG args)
#endif

/*
 * Transmit timeout, default 5 seconds.
 */
static int watchdog = 5000;
module_param(watchdog, int, 0400);
MODULE_PARM_DESC(watchdog, "transmit timeout in milliseconds");

/* Structure/enum declaration ------------------------------- */
typedef struct board_info {

        void __iomem *io_addr;  /* Register I/O base address */
        void __iomem *io_data;  /* Data I/O address */
        u16 irq;                /* IRQ */

        u16 tx_pkt_cnt;
        u16 queue_pkt_len;
        u16 queue_start_addr;
        u16 dbug_cnt;
        u8 io_mode;             /* 0:word, 2:byte */
        u8 phy_addr;

        void (*inblk)(void __iomem *port, void *data, int length);
        void (*outblk)(void __iomem *port, void *data, int length);
        void (*dumpblk)(void __iomem *port, int length);

        struct resource *addr_res;   /* resources found */
        struct resource *data_res;
        struct resource *addr_req;   /* resources requested */
        struct resource *data_req;
        struct resource *irq_res;

        struct timer_list timer;
        struct net_device_stats stats;
        unsigned char srom[128];
        spinlock_t lock;

        struct mii_if_info mii;
        u32 msg_enable;
} board_info_t;

/* function declaration ------------------------------------- */
static int dm9000_probe(struct platform_device *);
static int dm9000_open(struct net_device *);
static int dm9000_start_xmit(struct sk_buff *, struct net_device *);
static int dm9000_stop(struct net_device *);


static void dm9000_timer(unsigned long);
static void dm9000_init_dm9000(struct net_device *);

static struct net_device_stats *dm9000_get_stats(struct net_device *);

static irqreturn_t dm9000_interrupt(int, void *);

static int dm9000_phy_read(struct net_device *dev, int phyaddr_unsused, int reg);
static void dm9000_phy_write(struct net_device *dev, int phyaddr_unused, int reg,
                           int value);
static u16 read_srom_word(board_info_t *, int);
static void dm9000_rx(struct net_device *);
static void dm9000_hash_table(struct net_device *);

//#define DM9000_PROGRAM_EEPROM
#ifdef DM9000_PROGRAM_EEPROM
static void program_eeprom(board_info_t * db);
#endif
/* DM9000 network board routine ---------------------------- */

static void
dm9000_reset(board_info_t * db)
{
        PRINTK1("dm9000x: resetting\n");
        /* RESET device */
        writeb(DM9000_NCR, db->io_addr);
        udelay(200);
        writeb(NCR_RST, db->io_data);
        udelay(200);
}

/*
 *   Read a byte from I/O port
 */
static u8
ior(board_info_t * db, int reg)
{
        writeb(reg, db->io_addr);
        return readb(db->io_data);
}

/*
 *   Write a byte to I/O port
 */

static void
iow(board_info_t * db, int reg, int value)
{
        writeb(reg, db->io_addr);
        writeb(value, db->io_data);
}

/* routines for sending block to chip */

static void dm9000_outblk_8bit(void __iomem *reg, void *data, int count)
{
        writesb(reg, data, count);
}

static void dm9000_outblk_16bit(void __iomem *reg, void *data, int count)
{
        writesw(reg, data, (count+1) >> 1);
}

static void dm9000_outblk_32bit(void __iomem *reg, void *data, int count)
{
        writesl(reg, data, (count+3) >> 2);
}

/* input block from chip to memory */

static void dm9000_inblk_8bit(void __iomem *reg, void *data, int count)
{
        readsb(reg, data, count);
}


static void dm9000_inblk_16bit(void __iomem *reg, void *data, int count)
{
        readsw(reg, data, (count+1) >> 1);
}

static void dm9000_inblk_32bit(void __iomem *reg, void *data, int count)
{
        readsl(reg, data, (count+3) >> 2);
}

/* dump block from chip to null */

static void dm9000_dumpblk_8bit(void __iomem *reg, int count)
{
        int i;
        int tmp;

        for (i = 0; i < count; i++)
                tmp = readb(reg);
}

static void dm9000_dumpblk_16bit(void __iomem *reg, int count)
{
        int i;
        int tmp;

        count = (count + 1) >> 1;

        for (i = 0; i < count; i++)
                tmp = readw(reg);
}

static void dm9000_dumpblk_32bit(void __iomem *reg, int count)
{
        int i;
        int tmp;

        count = (count + 3) >> 2;

        for (i = 0; i < count; i++)
                tmp = readl(reg);
}

/* dm9000_set_io
 *
 * select the specified set of io routines to use with the
 * device
 */

static void dm9000_set_io(struct board_info *db, int byte_width)
{
        /* use the size of the data resource to work out what IO
         * routines we want to use
         */

        switch (byte_width) {
        case 1:
                db->dumpblk = dm9000_dumpblk_8bit;
                db->outblk  = dm9000_outblk_8bit;
                db->inblk   = dm9000_inblk_8bit;
                break;

        case 2:
                db->dumpblk = dm9000_dumpblk_16bit;
                db->outblk  = dm9000_outblk_16bit;
                db->inblk   = dm9000_inblk_16bit;
                break;

        case 3:
                printk(KERN_ERR PFX ": 3 byte IO, falling back to 16bit\n");
                db->dumpblk = dm9000_dumpblk_16bit;
                db->outblk  = dm9000_outblk_16bit;
                db->inblk   = dm9000_inblk_16bit;
                break;

        case 4:
        default:
                db->dumpblk = dm9000_dumpblk_32bit;
                db->outblk  = dm9000_outblk_32bit;
                db->inblk   = dm9000_inblk_32bit;
                break;
        }
}


/* Our watchdog timed out. Called by the networking layer */
static void dm9000_timeout(struct net_device *dev)
{
        board_info_t *db = (board_info_t *) dev->priv;
        u8 reg_save;
        unsigned long flags;

        /* Save previous register address */
        reg_save = readb(db->io_addr);
        spin_lock_irqsave(&db->lock,flags);

        netif_stop_queue(dev);
        dm9000_reset(db);
        dm9000_init_dm9000(dev);
        /* We can accept TX packets again */
        dev->trans_start = jiffies;
        netif_wake_queue(dev);

        /* Restore previous register address */
        writeb(reg_save, db->io_addr);
        spin_unlock_irqrestore(&db->lock,flags);
}

#ifdef CONFIG_NET_POLL_CONTROLLER
/*
 *Used by netconsole
 */
static void dm9000_poll_controller(struct net_device *dev)
{
        disable_irq(dev->irq);
        dm9000_interrupt(dev->irq,dev);
        enable_irq(dev->irq);
}
#endif

/* dm9000_release_board
 *
 * release a board, and any mapped resources
 */

static void
dm9000_release_board(struct platform_device *pdev, struct board_info *db)
{
        if (db->data_res == NULL) {
                if (db->addr_res != NULL)
                        release_mem_region((unsigned long)db->io_addr, 4);
                return;
        }

        /* unmap our resources */

        iounmap(db->io_addr);
        iounmap(db->io_data);

        /* release the resources */

        if (db->data_req != NULL) {
                release_resource(db->data_req);
                kfree(db->data_req);
        }

        if (db->addr_req != NULL) {
                release_resource(db->addr_req);
                kfree(db->addr_req);
        }
}

#define res_size(_r) (((_r)->end - (_r)->start) + 1)

/*
 * Search DM9000 board, allocate space and register it
 */
static int
dm9000_probe(struct platform_device *pdev)
{
        struct dm9000_plat_data *pdata = pdev->dev.platform_data;
        struct board_info *db;  /* Point a board information structure */
        struct net_device *ndev;
        unsigned long base;
        int ret = 0;
        int iosize;
        int i;
        u32 id_val;

        /* Init network device */
        ndev = alloc_etherdev(sizeof (struct board_info));
        if (!ndev) {
                printk("%s: could not allocate device.\n", CARDNAME);
                return -ENOMEM;
        }

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

        PRINTK2("dm9000_probe()");

        /* setup board info structure */
        db = (struct board_info *) ndev->priv;
        memset(db, 0, sizeof (*db));

        spin_lock_init(&db->lock);

        if (pdev->num_resources < 2) {
                ret = -ENODEV;
                goto out;
        } else if (pdev->num_resources == 2) {
                base = pdev->resource[0].start;

                if (!request_mem_region(base, 4, ndev->name)) {
                        ret = -EBUSY;
                        goto out;
                }

                ndev->base_addr = base;
                ndev->irq = pdev->resource[1].start;
                db->io_addr = (void __iomem *)base;
                db->io_data = (void __iomem *)(base + 4);

        } else {
                db->addr_res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
                db->data_res = platform_get_resource(pdev, IORESOURCE_MEM, 1);
                db->irq_res  = platform_get_resource(pdev, IORESOURCE_IRQ, 0);

                if (db->addr_res == NULL || db->data_res == NULL ||
                    db->irq_res == NULL) {
                        printk(KERN_ERR PFX "insufficient resources\n");
                        ret = -ENOENT;
                        goto out;
                }

                i = res_size(db->addr_res);
                db->addr_req = request_mem_region(db->addr_res->start, i,
                                                  pdev->name);

                if (db->addr_req == NULL) {
                        printk(KERN_ERR PFX "cannot claim address reg area\n");
                        ret = -EIO;
                        goto out;
                }

                db->io_addr = ioremap(db->addr_res->start, i);

                if (db->io_addr == NULL) {
                        printk(KERN_ERR "failed to ioremap address reg\n");
                        ret = -EINVAL;
                        goto out;
                }

                iosize = res_size(db->data_res);
                db->data_req = request_mem_region(db->data_res->start, iosize,
                                                  pdev->name);

                if (db->data_req == NULL) {
                        printk(KERN_ERR PFX "cannot claim data reg area\n");
                        ret = -EIO;
                        goto out;
                }

                db->io_data = ioremap(db->data_res->start, iosize);

                if (db->io_data == NULL) {
                        printk(KERN_ERR "failed to ioremap data reg\n");
                        ret = -EINVAL;
                        goto out;
                }

                /* fill in parameters for net-dev structure */

                ndev->base_addr = (unsigned long)db->io_addr;
                ndev->irq       = db->irq_res->start;

                /* ensure at least we have a default set of IO routines */
                dm9000_set_io(db, iosize);
        }

        /* check to see if anything is being over-ridden */
        if (pdata != NULL) {
                /* check to see if the driver wants to over-ride the
                 * default IO width */

                if (pdata->flags & DM9000_PLATF_8BITONLY)
                        dm9000_set_io(db, 1);

                if (pdata->flags & DM9000_PLATF_16BITONLY)
                        dm9000_set_io(db, 2);

                if (pdata->flags & DM9000_PLATF_32BITONLY)
                        dm9000_set_io(db, 4);

                /* check to see if there are any IO routine
                 * over-rides */

                if (pdata->inblk != NULL)
                        db->inblk = pdata->inblk;

                if (pdata->outblk != NULL)
                        db->outblk = pdata->outblk;

                if (pdata->dumpblk != NULL)
                        db->dumpblk = pdata->dumpblk;
        }

        dm9000_reset(db);

        /* try two times, DM9000 sometimes gets the first read wrong */
        for (i = 0; i < 2; i++) {
                id_val  = ior(db, DM9000_VIDL);
                id_val |= (u32)ior(db, DM9000_VIDH) << 8;
                id_val |= (u32)ior(db, DM9000_PIDL) << 16;
                id_val |= (u32)ior(db, DM9000_PIDH) << 24;

                if (id_val == DM9000_ID)
                        break;
                printk("%s: read wrong id 0x%08x\n", CARDNAME, id_val);
        }

        if (id_val != DM9000_ID) {
                printk("%s: wrong id: 0x%08x\n", CARDNAME, id_val);
                goto release;
        }

        /* from this point we assume that we have found a DM9000 */

        /* driver system function */
        ether_setup(ndev);

        ndev->open               = &dm9000_open;
        ndev->hard_start_xmit    = &dm9000_start_xmit;
        ndev->tx_timeout         = &dm9000_timeout;
        ndev->watchdog_timeo = msecs_to_jiffies(watchdog);
        ndev->stop               = &dm9000_stop;
        ndev->get_stats          = &dm9000_get_stats;
        ndev->set_multicast_list = &dm9000_hash_table;
#ifdef CONFIG_NET_POLL_CONTROLLER
        ndev->poll_controller    = &dm9000_poll_controller;
#endif

#ifdef DM9000_PROGRAM_EEPROM
        program_eeprom(db);
#endif
        db->msg_enable       = NETIF_MSG_LINK;
        db->mii.phy_id_mask  = 0x1f;
        db->mii.reg_num_mask = 0x1f;
        db->mii.force_media  = 0;
        db->mii.full_duplex  = 0;
        db->mii.dev          = ndev;
        db->mii.mdio_read    = dm9000_phy_read;
        db->mii.mdio_write   = dm9000_phy_write;

        /* Read SROM content */
        for (i = 0; i < 64; i++)
                ((u16 *) db->srom)[i] = read_srom_word(db, i);

        /* Set Node Address */
        for (i = 0; i < 6; i++)
                ndev->dev_addr[i] = db->srom[i];

        if (!is_valid_ether_addr(ndev->dev_addr)) {
                /* try reading from mac */

                for (i = 0; i < 6; i++)
                        ndev->dev_addr[i] = ior(db, i+DM9000_PAR);
        }

        if (!is_valid_ether_addr(ndev->dev_addr))
                printk("%s: Invalid ethernet MAC address.  Please "
                       "set using ifconfig\n", ndev->name);

        platform_set_drvdata(pdev, ndev);
        ret = register_netdev(ndev);

        if (ret == 0) {
                printk("%s: dm9000 at %p,%p IRQ %d MAC: ",
                       ndev->name,  db->io_addr, db->io_data, ndev->irq);
                for (i = 0; i < 5; i++)
                        printk("%02x:", ndev->dev_addr[i]);
                printk("%02x\n", ndev->dev_addr[5]);
        }
        return 0;

 release:
 out:
        printk("%s: not found (%d).\n", CARDNAME, ret);

        dm9000_release_board(pdev, db);
        kfree(ndev);

        return ret;
}

/*
 *  Open the interface.
 *  The interface is opened whenever "ifconfig" actives it.
 */
static int
dm9000_open(struct net_device *dev)
{
        board_info_t *db = (board_info_t *) dev->priv;

        PRINTK2("entering dm9000_open\n");

        if (request_irq(dev->irq, &dm9000_interrupt, IRQF_SHARED, dev->name, dev))
                return -EAGAIN;

        /* Initialize DM9000 board */
        dm9000_reset(db);
        dm9000_init_dm9000(dev);

        /* Init driver variable */
        db->dbug_cnt = 0;

        /* set and active a timer process */
        init_timer(&db->timer);
        db->timer.expires  = DM9000_TIMER_WUT;
        db->timer.data     = (unsigned long) dev;
        db->timer.function = &dm9000_timer;
        add_timer(&db->timer);

        mii_check_media(&db->mii, netif_msg_link(db), 1);
        netif_start_queue(dev);

        return 0;
}

/*
 * Initilize dm9000 board
 */
static void
dm9000_init_dm9000(struct net_device *dev)
{
        board_info_t *db = (board_info_t *) dev->priv;

        PRINTK1("entering %s\n",__FUNCTION__);

        /* I/O mode */
        db->io_mode = ior(db, DM9000_ISR) >> 6; /* ISR bit7:6 keeps I/O mode */

        /* GPIO0 on pre-activate PHY */
        iow(db, DM9000_GPR, 0); /* REG_1F bit0 activate phyxcer */
        iow(db, DM9000_GPCR, GPCR_GEP_CNTL);    /* Let GPIO0 output */
        iow(db, DM9000_GPR, 0); /* Enable PHY */

        /* Program operating register */
        iow(db, DM9000_TCR, 0);         /* TX Polling clear */
        iow(db, DM9000_BPTR, 0x3f);     /* Less 3Kb, 200us */
        iow(db, DM9000_FCR, 0xff);      /* Flow Control */
        iow(db, DM9000_SMCR, 0);        /* Special Mode */
        /* clear TX status */
        iow(db, DM9000_NSR, NSR_WAKEST | NSR_TX2END | NSR_TX1END);
        iow(db, DM9000_ISR, ISR_CLR_STATUS); /* Clear interrupt status */

        /* Set address filter table */
        dm9000_hash_table(dev);

        /* Activate DM9000 */
        iow(db, DM9000_RCR, RCR_DIS_LONG | RCR_DIS_CRC | RCR_RXEN);
        /* Enable TX/RX interrupt mask */
        iow(db, DM9000_IMR, IMR_PAR | IMR_PTM | IMR_PRM);

        /* Init Driver variable */
        db->tx_pkt_cnt = 0;
        db->queue_pkt_len = 0;
        dev->trans_start = 0;
}

/*
 *  Hardware start transmission.
 *  Send a packet to media from the upper layer.
 */
static int
dm9000_start_xmit(struct sk_buff *skb, struct net_device *dev)
{
        board_info_t *db = (board_info_t *) dev->priv;

        PRINTK3("dm9000_start_xmit\n");

        if (db->tx_pkt_cnt > 1)
                return 1;

        netif_stop_queue(dev);

        /* Disable all interrupts */
        iow(db, DM9000_IMR, IMR_PAR);

        /* Move data to DM9000 TX RAM */
        writeb(DM9000_MWCMD, db->io_addr);

        (db->outblk)(db->io_data, skb->data, skb->len);
        db->stats.tx_bytes += skb->len;

        /* TX control: First packet immediately send, second packet queue */
        if (db->tx_pkt_cnt == 0) {

                /* First Packet */
                db->tx_pkt_cnt++;

                /* Set TX length to DM9000 */
                iow(db, DM9000_TXPLL, skb->len & 0xff);
                iow(db, DM9000_TXPLH, (skb->len >> 8) & 0xff);

                /* Issue TX polling command */
                iow(db, DM9000_TCR, TCR_TXREQ); /* Cleared after TX complete */

                dev->trans_start = jiffies;     /* save the time stamp */

        } else {
                /* Second packet */
                db->tx_pkt_cnt++;
                db->queue_pkt_len = skb->len;
        }

        /* free this SKB */
        dev_kfree_skb(skb);

        /* Re-enable resource check */
        if (db->tx_pkt_cnt == 1)
                netif_wake_queue(dev);

        /* Re-enable interrupt */
        iow(db, DM9000_IMR, IMR_PAR | IMR_PTM | IMR_PRM);

        return 0;
}

static void
dm9000_shutdown(struct net_device *dev)
{
        board_info_t *db = (board_info_t *) dev->priv;

        /* RESET device */
        dm9000_phy_write(dev, 0, MII_BMCR, BMCR_RESET); /* PHY RESET */
        iow(db, DM9000_GPR, 0x01);      /* Power-Down PHY */
        iow(db, DM9000_IMR, IMR_PAR);   /* Disable all interrupt */
        iow(db, DM9000_RCR, 0x00);      /* Disable RX */
}

/*
 * Stop the interface.
 * The interface is stopped when it is brought.
 */
static int
dm9000_stop(struct net_device *ndev)
{
        board_info_t *db = (board_info_t *) ndev->priv;

        PRINTK1("entering %s\n",__FUNCTION__);

        /* deleted timer */
        del_timer(&db->timer);

        netif_stop_queue(ndev);
        netif_carrier_off(ndev);

        /* free interrupt */
        free_irq(ndev->irq, ndev);

        dm9000_shutdown(ndev);

        return 0;
}

/*
 * DM9000 interrupt handler
 * receive the packet to upper layer, free the transmitted packet
 */

static void
dm9000_tx_done(struct net_device *dev, board_info_t * db)
{
        int tx_status = ior(db, DM9000_NSR);    /* Got TX status */

        if (tx_status & (NSR_TX2END | NSR_TX1END)) {
                /* One packet sent complete */
                db->tx_pkt_cnt--;
                db->stats.tx_packets++;

                /* Queue packet check & send */
                if (db->tx_pkt_cnt > 0) {
                        iow(db, DM9000_TXPLL, db->queue_pkt_len & 0xff);
                        iow(db, DM9000_TXPLH, (db->queue_pkt_len >> 8) & 0xff);
                        iow(db, DM9000_TCR, TCR_TXREQ);
                        dev->trans_start = jiffies;
                }
                netif_wake_queue(dev);
        }
}

static irqreturn_t
dm9000_interrupt(int irq, void *dev_id)
{
        struct net_device *dev = dev_id;
        board_info_t *db;
        int int_status;
        u8 reg_save;

        PRINTK3("entering %s\n",__FUNCTION__);

        if (!dev) {
                PRINTK1("dm9000_interrupt() without DEVICE arg\n");
                return IRQ_HANDLED;
        }

        /* A real interrupt coming */
        db = (board_info_t *) dev->priv;
        spin_lock(&db->lock);

        /* Save previous register address */
        reg_save = readb(db->io_addr);

        /* Disable all interrupts */
        iow(db, DM9000_IMR, IMR_PAR);

        /* Got DM9000 interrupt status */
        int_status = ior(db, DM9000_ISR);       /* Got ISR */
        iow(db, DM9000_ISR, int_status);        /* Clear ISR status */

        /* Received the coming packet */
        if (int_status & ISR_PRS)
                dm9000_rx(dev);

        /* Trnasmit Interrupt check */
        if (int_status & ISR_PTS)
                dm9000_tx_done(dev, db);

        /* Re-enable interrupt mask */
        iow(db, DM9000_IMR, IMR_PAR | IMR_PTM | IMR_PRM);

        /* Restore previous register address */
        writeb(reg_save, db->io_addr);

        spin_unlock(&db->lock);

        return IRQ_HANDLED;
}

/*
 *  Get statistics from driver.
 */
static struct net_device_stats *
dm9000_get_stats(struct net_device *dev)
{
        board_info_t *db = (board_info_t *) dev->priv;
        return &db->stats;
}


/*
 *  A periodic timer routine
 *  Dynamic media sense, allocated Rx buffer...
 */
static void
dm9000_timer(unsigned long data)
{
        struct net_device *dev = (struct net_device *) data;
        board_info_t *db = (board_info_t *) dev->priv;

        PRINTK3("dm9000_timer()\n");

        mii_check_media(&db->mii, netif_msg_link(db), 0);

        /* Set timer again */
        db->timer.expires = DM9000_TIMER_WUT;
        add_timer(&db->timer);
}

struct dm9000_rxhdr {
        u16     RxStatus;
        u16     RxLen;
} __attribute__((__packed__));

/*
 *  Received a packet and pass to upper layer
 */
static void
dm9000_rx(struct net_device *dev)
{
        board_info_t *db = (board_info_t *) dev->priv;
        struct dm9000_rxhdr rxhdr;
        struct sk_buff *skb;
        u8 rxbyte, *rdptr;
        int GoodPacket;
        int RxLen;

        /* Check packet ready or not */
        do {
                ior(db, DM9000_MRCMDX); /* Dummy read */

                /* Get most updated data */
                rxbyte = readb(db->io_data);

                /* Status check: this byte must be 0 or 1 */
                if (rxbyte > DM9000_PKT_RDY) {
                        printk("status check failed: %d\n", rxbyte);
                        iow(db, DM9000_RCR, 0x00);      /* Stop Device */
                        iow(db, DM9000_ISR, IMR_PAR);   /* Stop INT request */
                        return;
                }

                if (rxbyte != DM9000_PKT_RDY)
                        return;

                /* A packet ready now  & Get status/length */
                GoodPacket = TRUE;
                writeb(DM9000_MRCMD, db->io_addr);

                (db->inblk)(db->io_data, &rxhdr, sizeof(rxhdr));

                RxLen = rxhdr.RxLen;

                /* Packet Status check */
                if (RxLen < 0x40) {
                        GoodPacket = FALSE;
                        PRINTK1("Bad Packet received (runt)\n");
                }

                if (RxLen > DM9000_PKT_MAX) {
                        PRINTK1("RST: RX Len:%x\n", RxLen);
                }

                if (rxhdr.RxStatus & 0xbf00) {
                        GoodPacket = FALSE;
                        if (rxhdr.RxStatus & 0x100) {
                                PRINTK1("fifo error\n");
                                db->stats.rx_fifo_errors++;
                        }
                        if (rxhdr.RxStatus & 0x200) {
                                PRINTK1("crc error\n");
                                db->stats.rx_crc_errors++;
                        }
                        if (rxhdr.RxStatus & 0x8000) {
                                PRINTK1("length error\n");
                                db->stats.rx_length_errors++;
                        }
                }

                /* Move data from DM9000 */
                if (GoodPacket
                    && ((skb = dev_alloc_skb(RxLen + 4)) != NULL)) {
                        skb->dev = dev;
                        skb_reserve(skb, 2);
                        rdptr = (u8 *) skb_put(skb, RxLen - 4);

                        /* Read received packet from RX SRAM */

                        (db->inblk)(db->io_data, rdptr, RxLen);
                        db->stats.rx_bytes += RxLen;

                        /* Pass to upper layer */
                        skb->protocol = eth_type_trans(skb, dev);
                        netif_rx(skb);
                        db->stats.rx_packets++;

                } else {
                        /* need to dump the packet's data */

                        (db->dumpblk)(db->io_data, RxLen);
                }
        } while (rxbyte == DM9000_PKT_RDY);
}

/*
 *  Read a word data from SROM
 */
static u16
read_srom_word(board_info_t * db, int offset)
{
        iow(db, DM9000_EPAR, offset);
        iow(db, DM9000_EPCR, EPCR_ERPRR);
        mdelay(8);              /* according to the datasheet 200us should be enough,
                                   but it doesn't work */
        iow(db, DM9000_EPCR, 0x0);
        return (ior(db, DM9000_EPDRL) + (ior(db, DM9000_EPDRH) << 8));
}

#ifdef DM9000_PROGRAM_EEPROM
/*
 * Write a word data to SROM
 */
static void
write_srom_word(board_info_t * db, int offset, u16 val)
{
        iow(db, DM9000_EPAR, offset);
        iow(db, DM9000_EPDRH, ((val >> 8) & 0xff));
        iow(db, DM9000_EPDRL, (val & 0xff));
        iow(db, DM9000_EPCR, EPCR_WEP | EPCR_ERPRW);
        mdelay(8);              /* same shit */
        iow(db, DM9000_EPCR, 0);
}

/*
 * Only for development:
 * Here we write static data to the eeprom in case
 * we don't have valid content on a new board
 */
static void
program_eeprom(board_info_t * db)
{
        u16 eeprom[] = { 0x0c00, 0x007f, 0x1300,        /* MAC Address */
                0x0000,         /* Autoload: accept nothing */
                0x0a46, 0x9000, /* Vendor / Product ID */
                0x0000,         /* pin control */
                0x0000,
        };                      /* Wake-up mode control */
        int i;
        for (i = 0; i < 8; i++)
                write_srom_word(db, i, eeprom[i]);
}
#endif


/*
 *  Calculate the CRC valude of the Rx packet
 *  flag = 1 : return the reverse CRC (for the received packet CRC)
 *         0 : return the normal CRC (for Hash Table index)
 */

static unsigned long
cal_CRC(unsigned char *Data, unsigned int Len, u8 flag)
{

       u32 crc = ether_crc_le(Len, Data);

       if (flag)
               return ~crc;

       return crc;
}

/*
 *  Set DM9000 multicast address
 */
static void
dm9000_hash_table(struct net_device *dev)
{
        board_info_t *db = (board_info_t *) dev->priv;
        struct dev_mc_list *mcptr = dev->mc_list;
        int mc_cnt = dev->mc_count;
        u32 hash_val;
        u16 i, oft, hash_table[4];
        unsigned long flags;

        PRINTK2("dm9000_hash_table()\n");

        spin_lock_irqsave(&db->lock,flags);

        for (i = 0, oft = 0x10; i < 6; i++, oft++)
                iow(db, oft, dev->dev_addr[i]);

        /* Clear Hash Table */
        for (i = 0; i < 4; i++)
                hash_table[i] = 0x0;

        /* broadcast address */
        hash_table[3] = 0x8000;

        /* the multicast address in Hash Table : 64 bits */
        for (i = 0; i < mc_cnt; i++, mcptr = mcptr->next) {
                hash_val = cal_CRC((char *) mcptr->dmi_addr, 6, 0) & 0x3f;
                hash_table[hash_val / 16] |= (u16) 1 << (hash_val % 16);
        }

        /* Write the hash table to MAC MD table */
        for (i = 0, oft = 0x16; i < 4; i++) {
                iow(db, oft++, hash_table[i] & 0xff);
                iow(db, oft++, (hash_table[i] >> 8) & 0xff);
        }

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


/*
 *   Read a word from phyxcer
 */
static int
dm9000_phy_read(struct net_device *dev, int phy_reg_unused, int reg)
{
        board_info_t *db = (board_info_t *) dev->priv;
        unsigned long flags;
        unsigned int reg_save;
        int ret;

        spin_lock_irqsave(&db->lock,flags);

        /* Save previous register address */
        reg_save = readb(db->io_addr);

        /* Fill the phyxcer register into REG_0C */
        iow(db, DM9000_EPAR, DM9000_PHY | reg);

        iow(db, DM9000_EPCR, 0xc);      /* Issue phyxcer read command */
        udelay(100);            /* Wait read complete */
        iow(db, DM9000_EPCR, 0x0);      /* Clear phyxcer read command */

        /* The read data keeps on REG_0D & REG_0E */
        ret = (ior(db, DM9000_EPDRH) << 8) | ior(db, DM9000_EPDRL);

        /* restore the previous address */
        writeb(reg_save, db->io_addr);

        spin_unlock_irqrestore(&db->lock,flags);

        return ret;
}

/*
 *   Write a word to phyxcer
 */
static void
dm9000_phy_write(struct net_device *dev, int phyaddr_unused, int reg, int value)
{
        board_info_t *db = (board_info_t *) dev->priv;
        unsigned long flags;
        unsigned long reg_save;

        spin_lock_irqsave(&db->lock,flags);

        /* Save previous register address */
        reg_save = readb(db->io_addr);

        /* Fill the phyxcer register into REG_0C */
        iow(db, DM9000_EPAR, DM9000_PHY | reg);

        /* Fill the written data into REG_0D & REG_0E */
        iow(db, DM9000_EPDRL, (value & 0xff));
        iow(db, DM9000_EPDRH, ((value >> 8) & 0xff));

        iow(db, DM9000_EPCR, 0xa);      /* Issue phyxcer write command */
        udelay(500);            /* Wait write complete */
        iow(db, DM9000_EPCR, 0x0);      /* Clear phyxcer write command */

        /* restore the previous address */
        writeb(reg_save, db->io_addr);

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

static int
dm9000_drv_suspend(struct platform_device *dev, pm_message_t state)
{
        struct net_device *ndev = platform_get_drvdata(dev);

        if (ndev) {
                if (netif_running(ndev)) {
                        netif_device_detach(ndev);
                        dm9000_shutdown(ndev);
                }
        }
        return 0;
}

static int
dm9000_drv_resume(struct platform_device *dev)
{
        struct net_device *ndev = platform_get_drvdata(dev);
        board_info_t *db = (board_info_t *) ndev->priv;

        if (ndev) {

                if (netif_running(ndev)) {
                        dm9000_reset(db);
                        dm9000_init_dm9000(ndev);

                        netif_device_attach(ndev);
                }
        }
        return 0;
}

static int
dm9000_drv_remove(struct platform_device *pdev)
{
        struct net_device *ndev = platform_get_drvdata(pdev);

        platform_set_drvdata(pdev, NULL);

        unregister_netdev(ndev);
        dm9000_release_board(pdev, (board_info_t *) ndev->priv);
        kfree(ndev);            /* free device structure */

        PRINTK1("clean_module() exit\n");

        return 0;
}

static struct platform_driver dm9000_driver = {
        .driver = {
                .name    = "dm9000",
                .owner   = THIS_MODULE,
        },
        .probe   = dm9000_probe,
        .remove  = dm9000_drv_remove,
        .suspend = dm9000_drv_suspend,
        .resume  = dm9000_drv_resume,
};

static int __init
dm9000_init(void)
{
        printk(KERN_INFO "%s Ethernet Driver\n", CARDNAME);

        return platform_driver_register(&dm9000_driver);        /* search board and register */
}

static void __exit
dm9000_cleanup(void)
{
        platform_driver_unregister(&dm9000_driver);
}

module_init(dm9000_init);
module_exit(dm9000_cleanup);

MODULE_AUTHOR("Sascha Hauer, Ben Dooks");
MODULE_DESCRIPTION("Davicom DM9000 network driver");
MODULE_LICENSE("GPL");