ARM-Linux驱动--DM9000网卡驱动分析（四）

 

1、接下来接着分析DM9000网卡驱动的数据接收函数

/*
 *  Received a packet and pass to upper layer
 *  接收数据包，将数据包传递给上层
 */
static void
dm9000_rx(struct net_device *dev)
{
    board_info_t *db = netdev_priv(dev);/* 得到网卡私有信息数据结构的首地址 */
    struct dm9000_rxhdr rxhdr;/* 该结构体封装了dm9000接收的数据包信息 */
    struct sk_buff *skb;
    u8 rxbyte, *rdptr;
    bool GoodPacket;
    int RxLen;

    /* Check packet ready or not */
    do {
        /* MRCMDX是内存数据预取读命令 */
        ior(db, DM9000_MRCMDX); /* Dummy read */
        /* Get most updated data */
        rxbyte = readb(db->io_data);

        /* Status check: this byte must be 0 or 1 */
        /* DM9000_PKT_ERR          0x02 ,表示接收出错 */
        if (rxbyte & DM9000_PKT_ERR) {
            dev_warn(db->dev, "status check fail: %d\n", rxbyte);/* 输出提示信息 */
            iow(db, DM9000_RCR, 0x00);  /* Stop Device 关闭设备 */
            iow(db, DM9000_ISR, IMR_PAR);   /* Stop INT request 停止中断请求*/
            return;
        }

        /* DM9000_PKT_RDY          0x01 没有准备好，直接返回*/
        if (!(rxbyte & DM9000_PKT_RDY))
            return;

        /* A packet ready now  & Get status/length */
        GoodPacket = true;
        writeb(DM9000_MRCMD, db->io_addr);/* MRCMD是地址增加的数据读取命令 */

        (db->inblk)(db->io_data, &rxhdr, sizeof(rxhdr));/* 读取数据，从RX_SRAM到 rxhdr结构体中*/

        RxLen = le16_to_cpu(rxhdr.RxLen);

        if (netif_msg_rx_status(db))
            dev_dbg(db->dev, "RX: status %02x, length %04x\n",
                rxhdr.RxStatus, RxLen);

        /* Packet Status check ，检查包的完整性*/
        if (RxLen < 0x40) {
            GoodPacket = false;
            if (netif_msg_rx_err(db))
                dev_dbg(db->dev, "RX: Bad Packet (runt)\n");
        }
        /* 如果数据长度大于DM9000_PKT_MAX ，即 1536 */
        if (RxLen > DM9000_PKT_MAX) {
            dev_dbg(db->dev, "RST: RX Len:%x\n", RxLen);
        }

        /* rxhdr.RxStatus is identical to RSR register. */
        /* 这里也是包的检查 */
        if (rxhdr.RxStatus & (RSR_FOE | RSR_CE | RSR_AE |
                      RSR_PLE | RSR_RWTO |
                      RSR_LCS | RSR_RF)) {
            GoodPacket = false;
            if (rxhdr.RxStatus & RSR_FOE) {
                if (netif_msg_rx_err(db))
                    dev_dbg(db->dev, "fifo error\n");
                dev->stats.rx_fifo_errors++;
            }
            if (rxhdr.RxStatus & RSR_CE) {
                if (netif_msg_rx_err(db))
                    dev_dbg(db->dev, "crc error\n");
                dev->stats.rx_crc_errors++;
            }
            if (rxhdr.RxStatus & RSR_RF) {
                if (netif_msg_rx_err(db))
                    dev_dbg(db->dev, "length error\n");
                dev->stats.rx_length_errors++;
            }
        }

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

            /* Read received packet from RX SRAM */
            /* 将RX SRAM中的数据读取到skbuff结构体 */
            (db->inblk)(db->io_data, rdptr, RxLen);
            dev->stats.rx_bytes += RxLen;

            /* Pass to upper layer */
            skb->protocol = eth_type_trans(skb, dev);
            if (db->rx_csum) {
                if ((((rxbyte & 0x1c) << 3) & rxbyte) == 0)
                    skb->ip_summed = CHECKSUM_UNNECESSARY;
                else
                    skb->ip_summed = CHECKSUM_NONE;
            }
            netif_rx(skb);/* 将skbuff结构体发送给上层 */
            dev->stats.rx_packets++;/* 计数增1 */

        } else {
            /* need to dump the packet's data */
            /* 坏包，丢弃 */
            (db->dumpblk)(db->io_data, RxLen);
        }
    } while (rxbyte & DM9000_PKT_RDY);
}

2、下面是完整的DM9000驱动代码，可以完整的查看

#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/ethtool.h>
#include <linux/dm9000.h>
#include <linux/delay.h>
#include <linux/platform_device.h>
#include <linux/irq.h>
#include <linux/slab.h>

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

#include "dm9000.h"

#include <mach/regs-gpio.h>
#include <mach/irqs.h>
#include <mach/hardware.h>

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

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

#define CARDNAME    "dm9000"
#define DRV_VERSION "1.31"

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

/* DM9000 register address locking.
 *
 * The DM9000 uses an address register to control where data written
 * to the data register goes. This means that the address register
 * must be preserved over interrupts or similar calls.
 *
 * During interrupt and other critical calls, a spinlock is used to
 * protect the system, but the calls themselves save the address
 * in the address register in case they are interrupting another
 * access to the device.
 *
 * For general accesses a lock is provided so that calls which are
 * allowed to sleep are serialised so that the address register does
 * not need to be saved. This lock also serves to serialise access
 * to the EEPROM and PHY access registers which are shared between
 * these two devices.
 */

/* The driver supports the original DM9000E, and now the two newer
 * devices, DM9000A and DM9000B.
 */

enum dm9000_type {
    TYPE_DM9000E,   /* original DM9000 */
    TYPE_DM9000A,
    TYPE_DM9000B
};

/* 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     queue_ip_summed;
    u16     dbug_cnt;
    u8      io_mode;        /* 0:word, 2:byte */
    u8      phy_addr;
    u8      imr_all;

    unsigned int    flags;
    unsigned int    in_suspend :1;
    unsigned int    wake_supported :1;
    int     debug_level;

    enum dm9000_type type;

    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 device   *dev;        /* parent device */

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

    int      irq_wake;

    struct mutex     addr_lock; /* phy and eeprom access lock */

    struct delayed_work phy_poll;
    struct net_device  *ndev;

    spinlock_t  lock;

    struct mii_if_info mii;
    u32     msg_enable;
    u32     wake_state;

    int     rx_csum;
    int     can_csum;
    int     ip_summed;
} board_info_t;

/* debug code */

#define dm9000_dbg(db, lev, msg...) do {        \
    if ((lev) < CONFIG_DM9000_DEBUGLEVEL &&      \
        (lev) < db->debug_level) {            \
        dev_dbg(db->dev, msg);           \
    }                       \
} while (0)

static inline board_info_t *to_dm9000_board(struct net_device *dev)
{
    return netdev_priv(dev);
}

/* DM9000 network board routine ---------------------------- */

static void
dm9000_reset(board_info_t * db)
{
    dev_dbg(db->dev, "resetting device\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 3:
        dev_dbg(db->dev, ": 3 byte IO, falling back to 16bit\n");
    case 2:
        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;
    }
}

static void dm9000_schedule_poll(board_info_t *db)
{
    if (db->type == TYPE_DM9000E)
        schedule_delayed_work(&db->phy_poll, HZ * 2);
}

static int dm9000_ioctl(struct net_device *dev, struct ifreq *req, int cmd)
{
    board_info_t *dm = to_dm9000_board(dev);

    if (!netif_running(dev))
        return -EINVAL;

    return generic_mii_ioctl(&dm->mii, if_mii(req), cmd, NULL);
}

static unsigned int
dm9000_read_locked(board_info_t *db, int reg)
{
    unsigned long flags;
    unsigned int ret;

    spin_lock_irqsave(&db->lock, flags);
    ret = ior(db, reg);
    spin_unlock_irqrestore(&db->lock, flags);

    return ret;
}

static int dm9000_wait_eeprom(board_info_t *db)
{
    unsigned int status;
    int timeout = 8;    /* wait max 8msec */

    /* The DM9000 data sheets say we should be able to
     * poll the ERRE bit in EPCR to wait for the EEPROM
     * operation. From testing several chips, this bit
     * does not seem to work.
     *
     * We attempt to use the bit, but fall back to the
     * timeout (which is why we do not return an error
     * on expiry) to say that the EEPROM operation has
     * completed.
     */

    while (1) {
        status = dm9000_read_locked(db, DM9000_EPCR);

        if ((status & EPCR_ERRE) == 0)
            break;

        msleep(1);

        if (timeout-- < 0) {
            dev_dbg(db->dev, "timeout waiting EEPROM\n");
            break;
        }
    }

    return 0;
}

/*
 *  Read a word data from EEPROM
 */
static void
dm9000_read_eeprom(board_info_t *db, int offset, u8 *to)
{
    unsigned long flags;

    if (db->flags & DM9000_PLATF_NO_EEPROM) {
        to[0] = 0xff;
        to[1] = 0xff;
        return;
    }

    mutex_lock(&db->addr_lock);

    spin_lock_irqsave(&db->lock, flags);

    iow(db, DM9000_EPAR, offset);
    iow(db, DM9000_EPCR, EPCR_ERPRR);

    spin_unlock_irqrestore(&db->lock, flags);

    dm9000_wait_eeprom(db);

    /* delay for at-least 150uS */
    msleep(1);

    spin_lock_irqsave(&db->lock, flags);

    iow(db, DM9000_EPCR, 0x0);

    to[0] = ior(db, DM9000_EPDRL);
    to[1] = ior(db, DM9000_EPDRH);

    spin_unlock_irqrestore(&db->lock, flags);

    mutex_unlock(&db->addr_lock);
}

/*
 * Write a word data to SROM
 */
static void
dm9000_write_eeprom(board_info_t *db, int offset, u8 *data)
{
    unsigned long flags;

    if (db->flags & DM9000_PLATF_NO_EEPROM)
        return;

    mutex_lock(&db->addr_lock);

    spin_lock_irqsave(&db->lock, flags);
    iow(db, DM9000_EPAR, offset);
    iow(db, DM9000_EPDRH, data[1]);
    iow(db, DM9000_EPDRL, data[0]);
    iow(db, DM9000_EPCR, EPCR_WEP | EPCR_ERPRW);
    spin_unlock_irqrestore(&db->lock, flags);

    dm9000_wait_eeprom(db);

    mdelay(1);  /* wait at least 150uS to clear */

    spin_lock_irqsave(&db->lock, flags);
    iow(db, DM9000_EPCR, 0);
    spin_unlock_irqrestore(&db->lock, flags);

    mutex_unlock(&db->addr_lock);
}

/* ethtool ops */

static void dm9000_get_drvinfo(struct net_device *dev,
                   struct ethtool_drvinfo *info)
{
    board_info_t *dm = to_dm9000_board(dev);

    strcpy(info->driver, CARDNAME);
    strcpy(info->version, DRV_VERSION);
    strcpy(info->bus_info, to_platform_device(dm->dev)->name);
}

static u32 dm9000_get_msglevel(struct net_device *dev)
{
    board_info_t *dm = to_dm9000_board(dev);

    return dm->msg_enable;
}

static void dm9000_set_msglevel(struct net_device *dev, u32 value)
{
    board_info_t *dm = to_dm9000_board(dev);

    dm->msg_enable = value;
}

static int dm9000_get_settings(struct net_device *dev, struct ethtool_cmd *cmd)
{
    board_info_t *dm = to_dm9000_board(dev);

    mii_ethtool_gset(&dm->mii, cmd);
    return 0;
}

static int dm9000_set_settings(struct net_device *dev, struct ethtool_cmd *cmd)
{
    board_info_t *dm = to_dm9000_board(dev);

    return mii_ethtool_sset(&dm->mii, cmd);
}

static int dm9000_nway_reset(struct net_device *dev)
{
    board_info_t *dm = to_dm9000_board(dev);
    return mii_nway_restart(&dm->mii);
}

static uint32_t dm9000_get_rx_csum(struct net_device *dev)
{
    board_info_t *dm = to_dm9000_board(dev);
    return dm->rx_csum;
}

static int dm9000_set_rx_csum_unlocked(struct net_device *dev, uint32_t data)
{
    board_info_t *dm = to_dm9000_board(dev);

    if (dm->can_csum) {
        dm->rx_csum = data;
        iow(dm, DM9000_RCSR, dm->rx_csum ? RCSR_CSUM : 0);

        return 0;
    }

    return -EOPNOTSUPP;
}

static int dm9000_set_rx_csum(struct net_device *dev, uint32_t data)
{
    board_info_t *dm = to_dm9000_board(dev);
    unsigned long flags;
    int ret;

    spin_lock_irqsave(&dm->lock, flags);
    ret = dm9000_set_rx_csum_unlocked(dev, data);
    spin_unlock_irqrestore(&dm->lock, flags);

    return ret;
}

static int dm9000_set_tx_csum(struct net_device *dev, uint32_t data)
{
    board_info_t *dm = to_dm9000_board(dev);
    int ret = -EOPNOTSUPP;

    if (dm->can_csum)
        ret = ethtool_op_set_tx_csum(dev, data);
    return ret;
}

static u32 dm9000_get_link(struct net_device *dev)
{
    board_info_t *dm = to_dm9000_board(dev);
    u32 ret;

    if (dm->flags & DM9000_PLATF_EXT_PHY)
        ret = mii_link_ok(&dm->mii);
    else
        ret = dm9000_read_locked(dm, DM9000_NSR) & NSR_LINKST ? 1 : 0;

    return ret;
}

#define DM_EEPROM_MAGIC     (0x444D394B)

static int dm9000_get_eeprom_len(struct net_device *dev)
{
    return 128;
}

static int dm9000_get_eeprom(struct net_device *dev,
                 struct ethtool_eeprom *ee, u8 *data)
{
    board_info_t *dm = to_dm9000_board(dev);
    int offset = ee->offset;
    int len = ee->len;
    int i;

    /* EEPROM access is aligned to two bytes */

    if ((len & 1) != 0 || (offset & 1) != 0)
        return -EINVAL;

    if (dm->flags & DM9000_PLATF_NO_EEPROM)
        return -ENOENT;

    ee->magic = DM_EEPROM_MAGIC;

    for (i = 0; i < len; i += 2)
        dm9000_read_eeprom(dm, (offset + i) / 2, data + i);

    return 0;
}

static int dm9000_set_eeprom(struct net_device *dev,
                 struct ethtool_eeprom *ee, u8 *data)
{
    board_info_t *dm = to_dm9000_board(dev);
    int offset = ee->offset;
    int len = ee->len;
    int i;

    /* EEPROM access is aligned to two bytes */

    if ((len & 1) != 0 || (offset & 1) != 0)
        return -EINVAL;

    if (dm->flags & DM9000_PLATF_NO_EEPROM)
        return -ENOENT;

    if (ee->magic != DM_EEPROM_MAGIC)
        return -EINVAL;

    for (i = 0; i < len; i += 2)
        dm9000_write_eeprom(dm, (offset + i) / 2, data + i);

    return 0;
}

static void dm9000_get_wol(struct net_device *dev, struct ethtool_wolinfo *w)
{
    board_info_t *dm = to_dm9000_board(dev);

    memset(w, 0, sizeof(struct ethtool_wolinfo));

    /* note, we could probably support wake-phy too */
    w->supported = dm->wake_supported ? WAKE_MAGIC : 0;
    w->wolopts = dm->wake_state;
}

static int dm9000_set_wol(struct net_device *dev, struct ethtool_wolinfo *w)
{
    board_info_t *dm = to_dm9000_board(dev);
    unsigned long flags;
    u32 opts = w->wolopts;
    u32 wcr = 0;

    if (!dm->wake_supported)
        return -EOPNOTSUPP;

    if (opts & ~WAKE_MAGIC)
        return -EINVAL;

    if (opts & WAKE_MAGIC)
        wcr |= WCR_MAGICEN;

    mutex_lock(&dm->addr_lock);

    spin_lock_irqsave(&dm->lock, flags);
    iow(dm, DM9000_WCR, wcr);
    spin_unlock_irqrestore(&dm->lock, flags);

    mutex_unlock(&dm->addr_lock);

    if (dm->wake_state != opts) {
        /* change in wol state, update IRQ state */

        if (!dm->wake_state)
            set_irq_wake(dm->irq_wake, 1);
        else if (dm->wake_state & !opts)
            set_irq_wake(dm->irq_wake, 0);
    }

    dm->wake_state = opts;
    return 0;
}

static const struct ethtool_ops dm9000_ethtool_ops = {
    .get_drvinfo        = dm9000_get_drvinfo,
    .get_settings       = dm9000_get_settings,
    .set_settings       = dm9000_set_settings,
    .get_msglevel       = dm9000_get_msglevel,
    .set_msglevel       = dm9000_set_msglevel,
    .nway_reset     = dm9000_nway_reset,
    .get_link       = dm9000_get_link,
    .get_wol        = dm9000_get_wol,
    .set_wol        = dm9000_set_wol,
    .get_eeprom_len     = dm9000_get_eeprom_len,
    .get_eeprom     = dm9000_get_eeprom,
    .set_eeprom     = dm9000_set_eeprom,
    .get_rx_csum        = dm9000_get_rx_csum,
    .set_rx_csum        = dm9000_set_rx_csum,
    .get_tx_csum        = ethtool_op_get_tx_csum,
    .set_tx_csum        = dm9000_set_tx_csum,
};

static void dm9000_show_carrier(board_info_t *db,
                unsigned carrier, unsigned nsr)
{
    struct net_device *ndev = db->ndev;
    unsigned ncr = dm9000_read_locked(db, DM9000_NCR);

    if (carrier)
        dev_info(db->dev, "%s: link up, %dMbps, %s-duplex, no LPA\n",
             ndev->name, (nsr & NSR_SPEED) ? 10 : 100,
             (ncr & NCR_FDX) ? "full" : "half");
    else
        dev_info(db->dev, "%s: link down\n", ndev->name);
}

static void
dm9000_poll_work(struct work_struct *w)
{
    struct delayed_work *dw = to_delayed_work(w);
    board_info_t *db = container_of(dw, board_info_t, phy_poll);
    struct net_device *ndev = db->ndev;

    if (db->flags & DM9000_PLATF_SIMPLE_PHY &&
        !(db->flags & DM9000_PLATF_EXT_PHY)) {
        unsigned nsr = dm9000_read_locked(db, DM9000_NSR);
        unsigned old_carrier = netif_carrier_ok(ndev) ? 1 : 0;
        unsigned new_carrier;

        new_carrier = (nsr & NSR_LINKST) ? 1 : 0;

        if (old_carrier != new_carrier) {
            if (netif_msg_link(db))
                dm9000_show_carrier(db, new_carrier, nsr);

            if (!new_carrier)
                netif_carrier_off(ndev);
            else
                netif_carrier_on(ndev);
        }
    } else
        mii_check_media(&db->mii, netif_msg_link(db), 0);

    if (netif_running(ndev))
        dm9000_schedule_poll(db);
}

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

static void
dm9000_release_board(struct platform_device *pdev, struct board_info *db)
{
    /* unmap our resources */

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

    /* release the resources */

    release_resource(db->data_req);
    kfree(db->data_req);

    release_resource(db->addr_req);
    kfree(db->addr_req);
}

static unsigned char dm9000_type_to_char(enum dm9000_type type)
{
    switch (type) {
    case TYPE_DM9000E: return 'e';
    case TYPE_DM9000A: return 'a';
    case TYPE_DM9000B: return 'b';
    }

    return '?';
}

/*
 *  Set DM9000 multicast address
 */
static void
dm9000_hash_table_unlocked(struct net_device *dev)
{
    board_info_t *db = netdev_priv(dev);
    struct netdev_hw_addr *ha;
    int i, oft;
    u32 hash_val;
    u16 hash_table[4];
    u8 rcr = RCR_DIS_LONG | RCR_DIS_CRC | RCR_RXEN;

    dm9000_dbg(db, 1, "entering %s\n", __func__);

    for (i = 0, oft = DM9000_PAR; 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;

    if (dev->flags & IFF_PROMISC)
        rcr |= RCR_PRMSC;

    if (dev->flags & IFF_ALLMULTI)
        rcr |= RCR_ALL;

    /* the multicast address in Hash Table : 64 bits */
    netdev_for_each_mc_addr(ha, dev) {
        hash_val = ether_crc_le(6, ha->addr) & 0x3f;
        hash_table[hash_val / 16] |= (u16) 1 << (hash_val % 16);
    }

    /* Write the hash table to MAC MD table */
    for (i = 0, oft = DM9000_MAR; i < 4; i++) {
        iow(db, oft++, hash_table[i]);
        iow(db, oft++, hash_table[i] >> 8);
    }

    iow(db, DM9000_RCR, rcr);
}

static void
dm9000_hash_table(struct net_device *dev)
{
    board_info_t *db = netdev_priv(dev);
    unsigned long flags;

    spin_lock_irqsave(&db->lock, flags);
    dm9000_hash_table_unlocked(dev);
    spin_unlock_irqrestore(&db->lock, flags);
}

/*
 * Initialize dm9000 board
 */
static void
dm9000_init_dm9000(struct net_device *dev)
{
    board_info_t *db = netdev_priv(dev);
    unsigned int imr;
    unsigned int ncr;

    dm9000_dbg(db, 1, "entering %s\n", __func__);

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

    /* Checksum mode */
    dm9000_set_rx_csum_unlocked(dev, db->rx_csum);

    /* 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 */

    ncr = (db->flags & DM9000_PLATF_EXT_PHY) ? NCR_EXT_PHY : 0;

    /* if wol is needed, then always set NCR_WAKEEN otherwise we end
     * up dumping the wake events if we disable this. There is already
     * a wake-mask in DM9000_WCR */
    if (db->wake_supported)
        ncr |= NCR_WAKEEN;

    iow(db, DM9000_NCR, ncr);

    /* 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_unlocked(dev);

    imr = IMR_PAR | IMR_PTM | IMR_PRM;
    if (db->type != TYPE_DM9000E)
        imr |= IMR_LNKCHNG;

    db->imr_all = imr;

    /* Enable TX/RX interrupt mask */
    iow(db, DM9000_IMR, imr);

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

/* Our watchdog timed out. Called by the networking layer */
static void dm9000_timeout(struct net_device *dev)
{
    board_info_t *db = netdev_priv(dev);
    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; /* prevent tx timeout */
    netif_wake_queue(dev);

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

static void dm9000_send_packet(struct net_device *dev,
                   int ip_summed,
                   u16 pkt_len)
{
    board_info_t *dm = to_dm9000_board(dev);

    /* The DM9000 is not smart enough to leave fragmented packets alone. */
    if (dm->ip_summed != ip_summed) {
        if (ip_summed == CHECKSUM_NONE)
            iow(dm, DM9000_TCCR, 0);
        else
            iow(dm, DM9000_TCCR, TCCR_IP | TCCR_UDP | TCCR_TCP);
        dm->ip_summed = ip_summed;
    }

    /* Set TX length to DM9000 */
    /* 设置TX数据的长度到寄存器TXPLL和TXPLH */
    iow(dm, DM9000_TXPLL, pkt_len);
    iow(dm, DM9000_TXPLH, pkt_len >> 8);

    /* Issue TX polling command */
    /* 设置发送控制寄存器的发送请求位 */
    iow(dm, DM9000_TCR, TCR_TXREQ); /* Cleared after TX complete */
}

/*
 *  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)
{
    unsigned long flags;
    board_info_t *db = netdev_priv(dev);/* 获取网卡虽有信息的存储结构信息的地址 */

    dm9000_dbg(db, 3, "%s:\n", __func__);

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

    spin_lock_irqsave(&db->lock, flags);/* 获得自旋锁 */

    /* Move data to DM9000 TX RAM */
    /*MWCMD 即 Memory data write command with address increment Register(F8H)
    * 根据 IO 操作模式(8-bit or 16-bit)来增加写指针 1 或 2
    */
    writeb(DM9000_MWCMD, db->io_addr);

    (db->outblk)(db->io_data, skb->data, skb->len);/* 将数据从sk_buff中copy到网卡的TX SRAM中 */

    dev->stats.tx_bytes += skb->len;/* 统计发送的字节数 */

    db->tx_pkt_cnt++;/* 待发送计数 */
    /* TX control: First packet immediately send, second packet queue */
    if (db->tx_pkt_cnt == 1) {
        dm9000_send_packet(dev, skb->ip_summed, skb->len);/* 如果计数为1，直接发送 */
    } else {/* 如果是第2个，则 */
        /* Second packet */
        db->queue_pkt_len = skb->len;
        db->queue_ip_summed = skb->ip_summed;
        netif_stop_queue(dev);/* 告诉上层停止发送 */
    }

    spin_unlock_irqrestore(&db->lock, flags);/* 解锁 */

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

    return NETDEV_TX_OK;
}

/*
 * 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)) {/* 第一个或第二个数据包发送完毕 */
        /* One packet sent complete */
        db->tx_pkt_cnt--;/* 待发送的数据包个数减1 */
        dev->stats.tx_packets++;/* 发送的数据包加1 */

        if (netif_msg_tx_done(db))
            dev_dbg(db->dev, "tx done, NSR %02x\n", tx_status);

        /* Queue packet check & send */
        if (db->tx_pkt_cnt > 0)/* 如果还有数据包 */
            dm9000_send_packet(dev, db->queue_ip_summed,
                       db->queue_pkt_len);
        netif_wake_queue(dev);/* 告诉内核，将数据包放入发生那个队列 */
    }
}

/* DM9000接收数据后的封装结构体，表示数据包的头4个字节 */
struct dm9000_rxhdr {
    u8  RxPktReady;
    u8  RxStatus;
    __le16  RxLen;
} __attribute__((__packed__));

/*
 *  Received a packet and pass to upper layer
 *  接收数据包，将数据包传递给上层
 */
static void
dm9000_rx(struct net_device *dev)
{
    board_info_t *db = netdev_priv(dev);/* 得到网卡私有信息数据结构的首地址 */
    struct dm9000_rxhdr rxhdr;/* 该结构体封装了dm9000接收的数据包信息 */
    struct sk_buff *skb;
    u8 rxbyte, *rdptr;
    bool GoodPacket;
    int RxLen;

    /* Check packet ready or not */
    do {
        /* MRCMDX是内存数据预取读命令 */
        ior(db, DM9000_MRCMDX); /* Dummy read */
        /* Get most updated data */
        rxbyte = readb(db->io_data);

        /* Status check: this byte must be 0 or 1 */
        /* DM9000_PKT_ERR          0x02 ,表示接收出错 */
        if (rxbyte & DM9000_PKT_ERR) {
            dev_warn(db->dev, "status check fail: %d\n", rxbyte);/* 输出提示信息 */
            iow(db, DM9000_RCR, 0x00);  /* Stop Device 关闭设备 */
            iow(db, DM9000_ISR, IMR_PAR);   /* Stop INT request 停止中断请求*/
            return;
        }

        /* DM9000_PKT_RDY          0x01 没有准备好，直接返回*/
        if (!(rxbyte & DM9000_PKT_RDY))
            return;

        /* A packet ready now  & Get status/length */
        GoodPacket = true;
        writeb(DM9000_MRCMD, db->io_addr);/* MRCMD是地址增加的数据读取命令 */

        (db->inblk)(db->io_data, &rxhdr, sizeof(rxhdr));/* 读取数据，从RX_SRAM到 rxhdr结构体中*/

        RxLen = le16_to_cpu(rxhdr.RxLen);

        if (netif_msg_rx_status(db))
            dev_dbg(db->dev, "RX: status %02x, length %04x\n",
                rxhdr.RxStatus, RxLen);

        /* Packet Status check ，检查包的完整性*/
        if (RxLen < 0x40) {
            GoodPacket = false;
            if (netif_msg_rx_err(db))
                dev_dbg(db->dev, "RX: Bad Packet (runt)\n");
        }
        /* 如果数据长度大于DM9000_PKT_MAX ，即 1536 */
        if (RxLen > DM9000_PKT_MAX) {
            dev_dbg(db->dev, "RST: RX Len:%x\n", RxLen);
        }

        /* rxhdr.RxStatus is identical to RSR register. */
        /* 这里也是包的检查 */
        if (rxhdr.RxStatus & (RSR_FOE | RSR_CE | RSR_AE |
                      RSR_PLE | RSR_RWTO |
                      RSR_LCS | RSR_RF)) {
            GoodPacket = false;
            if (rxhdr.RxStatus & RSR_FOE) {
                if (netif_msg_rx_err(db))
                    dev_dbg(db->dev, "fifo error\n");
                dev->stats.rx_fifo_errors++;
            }
            if (rxhdr.RxStatus & RSR_CE) {
                if (netif_msg_rx_err(db))
                    dev_dbg(db->dev, "crc error\n");
                dev->stats.rx_crc_errors++;
            }
            if (rxhdr.RxStatus & RSR_RF) {
                if (netif_msg_rx_err(db))
                    dev_dbg(db->dev, "length error\n");
                dev->stats.rx_length_errors++;
            }
        }

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

            /* Read received packet from RX SRAM */
            /* 将RX SRAM中的数据读取到skbuff结构体 */
            (db->inblk)(db->io_data, rdptr, RxLen);
            dev->stats.rx_bytes += RxLen;

            /* Pass to upper layer */
            skb->protocol = eth_type_trans(skb, dev);
            if (db->rx_csum) {
                if ((((rxbyte & 0x1c) << 3) & rxbyte) == 0)
                    skb->ip_summed = CHECKSUM_UNNECESSARY;
                else
                    skb->ip_summed = CHECKSUM_NONE;
            }
            netif_rx(skb);/* 将skbuff结构体发送给上层 */
            dev->stats.rx_packets++;/* 计数增1 */

        } else {
            /* need to dump the packet's data */
            /* 坏包，丢弃 */
            (db->dumpblk)(db->io_data, RxLen);
        }
    } while (rxbyte & DM9000_PKT_RDY);
}

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

    dm9000_dbg(db, 3, "entering %s\n", __func__);

    /* A real interrupt coming */

    /* holders of db->lock must always block IRQs */
    spin_lock_irqsave(&db->lock, flags);

    /* 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 */

    if (netif_msg_intr(db))
        dev_dbg(db->dev, "interrupt status %02x\n", int_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);

    if (db->type != TYPE_DM9000E) {
        if (int_status & ISR_LNKCHNG) {
            /* fire a link-change request */
            schedule_delayed_work(&db->phy_poll, 1);
        }
    }

    /* Re-enable interrupt mask */
    iow(db, DM9000_IMR, db->imr_all);

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

    spin_unlock_irqrestore(&db->lock, flags);

    return IRQ_HANDLED;
}

static irqreturn_t dm9000_wol_interrupt(int irq, void *dev_id)
{
    struct net_device *dev = dev_id;
    board_info_t *db = netdev_priv(dev);
    unsigned long flags;
    unsigned nsr, wcr;

    spin_lock_irqsave(&db->lock, flags);

    nsr = ior(db, DM9000_NSR);
    wcr = ior(db, DM9000_WCR);

    dev_dbg(db->dev, "%s: NSR=0x%02x, WCR=0x%02x\n", __func__, nsr, wcr);

    if (nsr & NSR_WAKEST) {
        /* clear, so we can avoid */
        iow(db, DM9000_NSR, NSR_WAKEST);

        if (wcr & WCR_LINKST)
            dev_info(db->dev, "wake by link status change\n");
        if (wcr & WCR_SAMPLEST)
            dev_info(db->dev, "wake by sample packet\n");
        if (wcr & WCR_MAGICST )
            dev_info(db->dev, "wake by magic packet\n");
        if (!(wcr & (WCR_LINKST | WCR_SAMPLEST | WCR_MAGICST)))
            dev_err(db->dev, "wake signalled with no reason? "
                "NSR=0x%02x, WSR=0x%02x\n", nsr, wcr);

    }

    spin_unlock_irqrestore(&db->lock, flags);

    return (nsr & NSR_WAKEST) ? IRQ_HANDLED : IRQ_NONE;
}

#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

/*
 *  Open the interface.
 *  The interface is opened whenever "ifconfig" actives it.
 */
static int
dm9000_open(struct net_device *dev)
{
    board_info_t *db = netdev_priv(dev);/* 返回board_info_t的地址 */
    unsigned long irqflags = db->irq_res->flags & IRQF_TRIGGER_MASK;

    if (netif_msg_ifup(db))
        dev_dbg(db->dev, "enabling %s\n", dev->name);

    /* If there is no IRQ type specified, default to something that
     * may work, and tell the user that this is a problem */

    if (irqflags == IRQF_TRIGGER_NONE)
        dev_warn(db->dev, "WARNING: no IRQ resource flags set.\n");

    irqflags |= IRQF_SHARED;

    /* 注册中断 */
    if (request_irq(dev->irq, dm9000_interrupt, irqflags, dev->name, dev))
        return -EAGAIN;

    /* Initialize DM9000 board */
    dm9000_reset(db);/* 复位DM9000 */
    dm9000_init_dm9000(dev);/* 根据net_device的数据初始化DM9000 */

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

    mii_check_media(&db->mii, netif_msg_link(db), 1);/* 检测mii接口的状态 */
    netif_start_queue(dev);/* 用来告诉上层网络协定这个驱动程序还有空的缓冲区可用，请把下 一个封包送进来。*/

    /*在probe函数中初始化的等待队列 INIT_DELAYED_WORK(&db->phy_poll, dm9000_poll_work);
    ＊初始化定时器，调用等待队列*/
    dm9000_schedule_poll(db);

    return 0;
}

/*
 * Sleep, either by using msleep() or if we are suspending, then
 * use mdelay() to sleep.
 */
static void dm9000_msleep(board_info_t *db, unsigned int ms)
{
    if (db->in_suspend)
        mdelay(ms);
    else
        msleep(ms);
}

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

    mutex_lock(&db->addr_lock);

    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, EPCR_ERPRR | EPCR_EPOS);   /* Issue phyxcer read command */

    writeb(reg_save, db->io_addr);
    spin_unlock_irqrestore(&db->lock,flags);

    dm9000_msleep(db, 1);       /* Wait read complete */

    spin_lock_irqsave(&db->lock,flags);
    reg_save = readb(db->io_addr);

    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);

    mutex_unlock(&db->addr_lock);

    dm9000_dbg(db, 5, "phy_read[%02x] -> %04x\n", reg, ret);
    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 = netdev_priv(dev);
    unsigned long flags;
    unsigned long reg_save;

    dm9000_dbg(db, 5, "phy_write[%02x] = %04x\n", reg, value);
    mutex_lock(&db->addr_lock);

    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);
    iow(db, DM9000_EPDRH, value >> 8);

    iow(db, DM9000_EPCR, EPCR_EPOS | EPCR_ERPRW);   /* Issue phyxcer write command */

    writeb(reg_save, db->io_addr);
    spin_unlock_irqrestore(&db->lock, flags);

    dm9000_msleep(db, 1);       /* Wait write complete */

    spin_lock_irqsave(&db->lock,flags);
    reg_save = readb(db->io_addr);

    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);
    mutex_unlock(&db->addr_lock);
}

/* 复位 phy，配置寄存器GPR位0为1，关闭dm9000电源，配置寄存器IMR位7为1，disable中断，配置寄存器RCR，disable接收 */
static void
dm9000_shutdown(struct net_device *dev)
{
    board_info_t *db = netdev_priv(dev);/* 获取网卡私有信息的地址 */

    /* RESET device */
    dm9000_phy_write(dev, 0, MII_BMCR, BMCR_RESET); /* PHY RESET ,复位PHY*/
    iow(db, DM9000_GPR, 0x01);  /* Power-Down PHY ，关闭PHY*/
    iow(db, DM9000_IMR, IMR_PAR);   /* Disable all interrupt ，关闭所有的中断*/
    iow(db, DM9000_RCR, 0x00);  /* Disable RX ,不再接受数据*/
}

/*
 * Stop the interface.
 * The interface is stopped when it is brought.
 */
static int
dm9000_stop(struct net_device *ndev)
{
    board_info_t *db = netdev_priv(ndev);/* 同上，获取网卡的私有结构信息的地址 */

    if (netif_msg_ifdown(db))
        dev_dbg(db->dev, "shutting down %s\n", ndev->name);

    cancel_delayed_work_sync(&db->phy_poll);/* 终止phy_poll队列中被延迟的任务 */

    netif_stop_queue(ndev);/* 关闭发送队列 */
    netif_carrier_off(ndev);/*通知该内核设备载波丢失,大部分涉及实际的物理连接的网络技术提供有一个载波状态,载波存在说明硬件存在并准备好*/

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

    dm9000_shutdown(ndev);/* 关闭DM9000网卡 */

    return 0;
}

static const struct net_device_ops dm9000_netdev_ops = {
    .ndo_open       = dm9000_open,/* 打开设备函数 */
    .ndo_stop       = dm9000_stop,/* 关闭设备函数 */
    .ndo_start_xmit     = dm9000_start_xmit,/* 开始发送数据 */
    .ndo_tx_timeout     = dm9000_timeout,/* 发送超时 */
    .ndo_set_multicast_list = dm9000_hash_table,/* 设定多播列表 */
    .ndo_do_ioctl       = dm9000_ioctl,/* io操作函数 */
    .ndo_change_mtu     = eth_change_mtu,/* 改变MTU */
    .ndo_validate_addr  = eth_validate_addr,
    .ndo_set_mac_address    = eth_mac_addr,
#ifdef CONFIG_NET_POLL_CONTROLLER
    .ndo_poll_controller    = dm9000_poll_controller,
#endif
};

/*
 * Search DM9000 board, allocate space and register it
 */
static int __devinit
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;/* 网络设备 */
    const unsigned char *mac_src;
    int ret = 0;
    int iosize;
    int i;
    u32 id_val;

    unsigned char ne_def_eth_mac_addr[]={0x00,0x12,0x34,0x56,0x80,0x49};/* 设定默认的mac地址 */
    static void *bwscon;/* 保存ioremap返回的寄存器的虚拟地址，下同 */
    static void *gpfcon;
    static void *extint0;
    static void *intmsk;
    /*Added by yan*/
    #define BWSCON           (0x48000000)
    #define GPFCON           (0x56000050)
    #define EXTINT0           (0x56000088)
    #define INTMSK           (0x4A000008)

    bwscon=ioremap_nocache(BWSCON,0x0000004);
    gpfcon=ioremap_nocache(GPFCON,0x0000004);
    extint0=ioremap_nocache(EXTINT0,0x0000004);
    intmsk=ioremap_nocache(INTMSK,0x0000004);

    writel( readl(bwscon)|0xc0000,bwscon);/* 将BWSCON寄存器[19:18]设置为11 */
    writel( (readl(gpfcon) & ~(0x3 << 14)) | (0x2 << 14), gpfcon); /* 设置GPF寄存器 */
    writel( readl(gpfcon) | (0x1 << 7), gpfcon); // Disable pull-up，不使能上拉
    writel( (readl(extint0) & ~(0xf << 28)) | (0x4 << 28), extint0); //rising edge，设置上升沿触发中断
    writel( (readl(intmsk))  & ~0x80, intmsk);/* 设置中断屏蔽寄存器 */

    /*End of add*/
    /* Init network device */
    /* 使用alloc_etherdev()函数分配一个网络设备的结构体，原型在include/linux/etherdevice.h */
    ndev = alloc_etherdev(sizeof(struct board_info));
    if (!ndev) {
        dev_err(&pdev->dev, "could not allocate device.\n");
        return -ENOMEM;
    }

/*通过SET_NETDEV_DEV(netdev, &pdev->dev)宏设置net_device.device->parent为当前的pci_device->device
*(这儿net_device包含的是device结构，而不是指针）。这样，就建立起了net_device到device的联系。
*/
    SET_NETDEV_DEV(ndev, &pdev->dev);

    dev_dbg(&pdev->dev, "dm9000_probe()\n");

    /* setup board info structure */
    /* 下面都是设置board_info结构体 */
    db = netdev_priv(ndev);/* 返回dev->priv的地址 */

    db->dev = &pdev->dev;
    db->ndev = ndev;

    spin_lock_init(&db->lock);
    mutex_init(&db->addr_lock);

    INIT_DELAYED_WORK(&db->phy_poll, dm9000_poll_work);

    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) {
        dev_err(db->dev, "insufficient resources\n");
        ret = -ENOENT;
        goto out;
    }

    db->irq_wake = platform_get_irq(pdev, 1);
    if (db->irq_wake >= 0) {
        dev_dbg(db->dev, "wakeup irq %d\n", db->irq_wake);

        ret = request_irq(db->irq_wake, dm9000_wol_interrupt,
                  IRQF_SHARED, dev_name(db->dev), ndev);
        if (ret) {
            dev_err(db->dev, "cannot get wakeup irq (%d)\n", ret);
        } else {

            /* test to see if irq is really wakeup capable */
            ret = set_irq_wake(db->irq_wake, 1);
            if (ret) {
                dev_err(db->dev, "irq %d cannot set wakeup (%d)\n",
                    db->irq_wake, ret);
                ret = 0;
            } else {
                set_irq_wake(db->irq_wake, 0);
                db->wake_supported = 1;
            }
        }
    }

    iosize = resource_size(db->addr_res);
    db->addr_req = request_mem_region(db->addr_res->start, iosize,
                      pdev->name);

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

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

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

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

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

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

    if (db->io_data == NULL) {
        dev_err(db->dev, "failed to ioremap data reg\n");
        ret = -EINVAL;
        goto out;
    }
    /* 设置结构体board_info结束 */

    /* fill in parameters for net-dev structure */
    ndev->base_addr = (unsigned long)db->io_addr;/* 设置网络设备的地址 */
    ndev->irq    = db->irq_res->start;/* 设置网络设备的中断资源地址 */

    /* 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 */

    /*根据pdev->dev.platform_data的信息判断IO的宽度并设置相应的宽度*/
    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;

        db->flags = pdata->flags;
    }

#ifdef CONFIG_DM9000_FORCE_SIMPLE_PHY_POLL
    db->flags |= DM9000_PLATF_SIMPLE_PHY;
#endif

    dm9000_reset(db);/* 复位 */

    /* try multiple times, DM9000 sometimes gets the read wrong */
    for (i = 0; i < 8; 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;
        dev_err(db->dev, "read wrong id 0x%08x\n", id_val);
    }

    if (id_val != DM9000_ID) {
        dev_err(db->dev, "wrong id: 0x%08x\n", id_val);
        ret = -ENODEV;
        goto out;
    }

    /* Identify what type of DM9000 we are working on */

    id_val = ior(db, DM9000_CHIPR);
    dev_dbg(db->dev, "dm9000 revision 0x%02x\n", id_val);

    switch (id_val) {
    case CHIPR_DM9000A:
        db->type = TYPE_DM9000A;
        break;
    case CHIPR_DM9000B:
        db->type = TYPE_DM9000B;
        break;
    default:
        dev_dbg(db->dev, "ID %02x => defaulting to DM9000E\n", id_val);
        db->type = TYPE_DM9000E;
    }

    /* dm9000a/b are capable of hardware checksum offload */
    if (db->type == TYPE_DM9000A || db->type == TYPE_DM9000B) {
        db->can_csum = 1;
        db->rx_csum = 1;
        ndev->features |= NETIF_F_IP_CSUM;
    }

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

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

    ndev->netdev_ops = &dm9000_netdev_ops;
    ndev->watchdog_timeo = msecs_to_jiffies(watchdog);
    ndev->ethtool_ops    = &dm9000_ethtool_ops;

    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;

    mac_src = "eeprom";

    /* try reading the node address from the attached EEPROM */
    for (i = 0; i < 6; i += 2)
        dm9000_read_eeprom(db, i / 2, ndev->dev_addr+i);

    if (!is_valid_ether_addr(ndev->dev_addr) && pdata != NULL) {
        mac_src = "platform data";
        memcpy(ndev->dev_addr, pdata->dev_addr, 6);
    }

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

        mac_src = "chip";
        for (i = 0; i < 6; i++)
            ndev->dev_addr[i] = ne_def_eth_mac_addr[i];
    }

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

    /* 设置pdev->dev->driver_data为ndev，保存成平台设备总线上的数据，以后使用只需platform_get_drvdata()即可*/
    platform_set_drvdata(pdev, ndev);

    /* 注册该网络设备 */
    ret = register_netdev(ndev);

    if (ret == 0)
        printk(KERN_INFO "%s: dm9000%c at %p,%p IRQ %d MAC: %pM (%s)\n",
               ndev->name, dm9000_type_to_char(db->type),
               db->io_addr, db->io_data, ndev->irq,
               ndev->dev_addr, mac_src);
    return 0;

/* 异常处理 */
out:
    dev_err(db->dev, "not found (%d).\n", ret);

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

    return ret;
}

/* 该函数是将设备从内核中移除，释放资源，在移除设备驱动时执行 */
static int __devexit
dm9000_drv_remove(struct platform_device *pdev)
{
    struct net_device *ndev = platform_get_drvdata(pdev);/* 从总线获取probe函数保存到总线的设备信息 */

    platform_set_drvdata(pdev, NULL);/* 释放pdev资源 */

    unregister_netdev(ndev);/* 解除网络设备 */
    dm9000_release_board(pdev, (board_info_t *) netdev_priv(ndev));/* 释放该设备申请的IO资源 */
    free_netdev(ndev);      /* free device structure */

    dev_dbg(&pdev->dev, "released and freed device\n");
    return 0;
}

/*平台设备驱动的结构体定义
*在该结构体中可以定义有关Power Management的管理函数
*该驱动中将其省略，侧重分析dm9000的基本原理
*/
static struct platform_driver dm9000_driver = {
    .driver = {
        .name    = "dm9000",/* 该名称和系统初始化中，平台设备的名称一致 */
        .owner   = THIS_MODULE,
    },
    .probe   = dm9000_probe,/* 资源探测函数 */
    .remove  = __devexit_p(dm9000_drv_remove),/* 设备移除函数 */
};

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

    return platform_driver_register(&dm9000_driver);
}

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

module_init(dm9000_init);
module_exit(dm9000_cleanup);

MODULE_AUTHOR("Modified by yan");
MODULE_DESCRIPTION("Davicom DM9000 network driver");
MODULE_LICENSE("GPL");
MODULE_ALIAS("platform:dm9000");