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内核版本：2.6.35

主机平台：Ubuntu 11.04

内核版本：2.6.39

原创作品，转载请标明出处http://blog.csdn.net/yming0221/article/details/6612623

下面开始分析具体的代码，这里由于使DM9000驱动更容易理解，在不影响基本的功能的前提下，这里将尽可能的简化该驱动（如：去掉该驱动中支持电源管理的功能）

分析该驱动

1、首先看一下该驱动的平台设备驱动的结构体定义

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static struct platform_driver dm9000_driver = {

.driver = {

.name = "dm9000",

.owner = THIS_MODULE,

},

.probe = dm9000_probe,

.remove = __devexit_p(dm9000_drv_remove),

};

在执行insmod后内核自动那个执行下面的函数

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static int __init

dm9000_init(void)

{

printk(KERN_INFO "%s Ethernet Driver, V%sn", CARDNAME, DRV_VERSION);

return platform_driver_register(&dm9000_driver);

}

调用函数platform_driver_register()函数注册驱动。

3、自动执行驱动的probe函数，进行资源的探测和申请资源。

其中BWSCON为总线宽度 等待控制寄存器

其中第[19:18]位的作用如下

下面函数中将两位设置为11，也就是WAIT使能，bank4使用UB/LB。

alloc_etherdev()函数分配一个网络设备的结构体，原型在include/linux/etherdevice.h

原型如下：

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extern struct net_device *alloc_etherdev_mq(int sizeof_priv, unsigned int queue_count);

#define alloc_etherdev(sizeof_priv) alloc_etherdev_mq(sizeof_priv, 1)

该函数中需要将获得的资源信息存储在一个结构体中，定义如下：

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typedef struct board_info {

void __iomem *io_addr;

void __iomem *io_data;

u16 irq;

u16 tx_pkt_cnt;

u16 queue_pkt_len;

u16 queue_start_addr;

u16 queue_ip_summed;

u16 dbug_cnt;

u8 io_mode;

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;

struct resource *addr_res;

struct resource *data_res;

struct resource *addr_req;

struct resource *data_req;

struct resource *irq_res;

int irq_wake;

struct mutex addr_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;

下面是probe函数，

其中有个函数db = netdev_priv(ndev)

该函数实际上是返回网卡私有成员的数据结构地址

函数如下，定义在include/linux/net_device.h中

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static inline void *netdev_priv(const struct net_device *dev)

{

return (char *)dev + ALIGN(sizeof(struct net_device), NETDEV_ALIGN);

}

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static int __devinit

dm9000_probe(struct platform_device *pdev)

{

struct dm9000_plat_data *pdata = pdev->dev.platform_data;

struct board_info *db;

struct net_device *ndev;

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};

static void *bwscon;

static void *gpfcon;

static void *extint0;

static void *intmsk;

#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);

writel( (readl(gpfcon) & ~(0x3 << 14)) | (0x2 << 14), gpfcon);

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);

ndev = alloc_etherdev(sizeof(struct board_info));

if (!ndev) {

dev_err(&pdev->dev, "could not allocate device.n");

return -ENOMEM;

}

SET_NETDEV_DEV(ndev, &pdev->dev);

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

db = netdev_priv(ndev);

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 resourcesn");

ret = -ENOENT;

goto out;

}

db->irq_wake = platform_get_irq(pdev, 1);

if (db->irq_wake >= 0) {

dev_dbg(db->dev, "wakeup irq %dn", 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 {

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 arean");

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 regn");

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 arean");

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 regn");

ret = -EINVAL;

goto out;

}

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

ndev->irq = db->irq_res->start;

dm9000_set_io(db, iosize);

if (pdata != NULL) {

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);

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);

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 0xxn", id_val);

}

if (id_val != DM9000_ID) {

dev_err(db->dev, "wrong id: 0xxn", id_val);

ret = -ENODEV;

goto out;

}

id_val = ior(db, DM9000_CHIPR);

dev_dbg(db->dev, "dm9000 revision 0xxn", 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 x => defaulting to DM9000En", id_val);

db->type = TYPE_DM9000E;

}

if (db->type == TYPE_DM9000A || db->type == TYPE_DM9000B) {

db->can_csum = 1;

db->rx_csum = 1;

ndev->features |= NETIF_F_IP_CSUM;

}

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";

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)) {

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 ifconfign", ndev->name);

platform_set_drvdata(pdev, ndev);

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;

out:

dev_err(db->dev, "not found (%d).n", ret);

dm9000_release_board(pdev, db);

free_netdev(ndev);

return ret;

}

这样，最后完成了网络设备的数据保存到总线上，将网络设备注册到内核。

4、设备的移除函数

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static int __devexit

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 *) netdev_priv(ndev));

free_netdev(ndev);

dev_dbg(&pdev->dev, "released and freed devicen");

return 0;

}