基于mini2440的DM9000网卡驱动分析probe函数部分

此为源代码，是基于mini2440开发板的DM9000网卡驱动程序，内核版本为Linux2.6.32.2

以下是对内核源码的拷贝，并对源码进行了个人的分析，如有错误之处，请指正，万分感谢。

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;

const unsigned char *mac_src;

int ret = 0;

int iosize;

int i;

u32 id_val;

/*初始化一个网络设备alloc_etherdev函数为alloc_netdev针对以太网的“快捷”函数，用于分配一个net_device结构体并对其成员赋值*/

/* Init network device */

ndev = alloc_etherdev(sizeof(struct board_info));

if (!ndev) {

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

return -ENOMEM;

}

/* Set the sysfs physical device reference for the network logical device

* if set prior to registration will cause a symlink during initialization.

*/

SET_NETDEV_DEV(ndev, &pdev->dev);

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

/*设置板信息结构体，填充board_info结构*/

/* setup board info structure */

/*得到网络设备私有数据，并初始化它*/

db = netdev_priv(ndev);

/*初始化设备私有数据*/

db->dev = &pdev->dev;

db->ndev = ndev;

/*初始化自旋锁和互斥锁*/

spin_lock_init(&db->lock);

mutex_init(&db->addr_lock);

/*初始化延时工作队列，phy_poll为一个延时的工作队列，dm_poll_work为一个时间到了的处理函数*/

INIT_DELAYED_WORK(&db->phy_poll, dm9000_poll_work);

/*获得平台资源，dm9000地址、数据、中断，在mach-mini2440.c中有定义*/

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;

}

/*为dm9000地址资源申请内存*/

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;

}

/*映射*/

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;

}

/*为dm9000的数据资源申请内存*/

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;

}

/*映射*/

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;

}

/*为net_device填充参数*/

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

ndev->base_addr = (unsigned long)db->io_addr; //数据地址

ndev->irq = db->irq_res->start; //中断起始地址

/* ensure at least we have a default set of IO routines */

dm9000_set_io(db, iosize); //设置IO操作的默认位宽

/*检查是否有设置dm9000的IO操作位宽，若果有，则进行设置新的位宽*/

/* 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 */

/*检查是否有对IO模式的设置操作*/

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复位，对dm9000内部寄存器的网络控制寄存器NCR第0位置1进行软件复位*/

dm9000_reset(db);

/*读取生产厂家序列号VID和产品序列号PID，为0x90000A46，多次读取确保不会发生错误*/

/* 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;

/*识别dm9000的ID*/

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 */

/*获得DM9000芯片修订版本，以证实是DM9000A还是DM9000B缺省为DM9000E*/

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;

}

/*无论是哪种修订版本都能够进行硬件的检验和*/

/* dm9000a/b are capable of hardware checksum offload */

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

db->can_csum = 1; //校验和标志

db->rx_csum = 1; //校验和标志

ndev->features |= NETIF_F_IP_CSUM; /* Can checksum TCP/UDP over IPv4.能通过IPV4来进行TCP/UDP协议的校验和检测
*/

}

/*在这里我们可以确保我们找到了一个DM9000设备*/

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

/* driver system function */

/*初始化以太网设备的公用成员，主要是对以太网设备的一些公用的操作进行设定，是固定的一些设置，如：设置对以太网头的操作，以太网数据发送类型10Mbps，以太网头部字节数14个字节，以太网最大传输字节数1500字节，以太网地址字节数6字节，以太网发送队列1000，以太网设备标识——广播地址有效和支持多点传送，设置6个字节广播地址都为0xFF,使用ether_setup(ndev)函数*/

ether_setup(ndev);

/*设置设备的成员函数指针*/

ndev->netdev_ops = &dm9000_netdev_ops; //dm9000网络设备操作

ndev->watchdog_timeo = msecs_to_jiffies(watchdog); //看门狗定时器

ndev->ethtool_ops = &dm9000_ethtool_ops; /*以太网协议操作，用来查询和设置网卡参数*/

/*以下是对MII进行初始化，MII（媒体独立接口）用来连接MAC和PHY的一个接口，它是IEEE-802.3定义的以太网行业标准，包括一个数据接口和一个MAC和PHY之间的管理接口。数据接口包括分别用于发送和接受的两条独立信道，每条信道都有自己的数据、时钟和控制信号，MII数据接口总共需要16个信号。MII管理接口包含两个信号，一个是时钟信号，另一个是数据信号。通过管理接口上层能监视和控制PHY。

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";

/*读取节点地址从附带的EEPROM中，在mini2440中没有外界eeprom，所以读出来的都是0xff*/

/* 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);

/*检查以太网地址是否有效FF：FF：FF：FF：FF：FF是一个多点播放地址，我们不需要去明确的去检查它*/

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 */

/*尝试读取MAC地址*/

mac_src = "chip";

for (i = 0; i < 6; i++)

ndev->dev_addr[i] = ior(db, i+DM9000_PAR);

}

/*设置MAC地址为08:90:90:90:90:90*/

memcpy(ndev->dev_addr, "\x08\x90\x90\x90\x90\x90", 6);

if (!is_valid_ether_addr(ndev->dev_addr))

dev_warn(db->dev, "%s: Invalid ethernet MAC address. Please "

"set using ifconfig\n", ndev->name);

/*设置平台数据*/

platform_set_drvdata(pdev, ndev);

/*注册驱动*/

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;

//错误处理

out:

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

dm9000_release_board(pdev, db); //释放板资源

free_netdev(ndev); //释放网络设备

return ret;

}

static int

dm9000_drv_suspend(struct device *dev)

{

struct platform_device *pdev = to_platform_device(dev);

struct net_device *ndev = platform_get_drvdata(pdev);

board_info_t *db;

if (ndev) {

db = netdev_priv(ndev);//获得设备私有数据

db->in_suspend = 1; //挂载标志设置

if (netif_running(ndev)) {

netif_device_detach(ndev); //设置device为为连接状态

dm9000_shutdown(ndev); //关电源

}

}

return 0;

}

static int

dm9000_drv_resume(struct device *dev)

{

struct platform_device *pdev = to_platform_device(dev);

struct net_device *ndev = platform_get_drvdata(pdev);

board_info_t *db = netdev_priv(ndev);

if (ndev) {

if (netif_running(ndev)) {

dm9000_reset(db); //复位

dm9000_init_dm9000(ndev); //重新初始化

netif_device_attach(ndev); //设置device为连接状态

}

db->in_suspend = 0; //挂载标志

}

return 0;

}

/*驱动电源管理操作*/

static struct dev_pm_ops dm9000_drv_pm_ops = {

.suspend = dm9000_drv_suspend, //挂载

.resume = dm9000_drv_resume, //恢复

};

static int __devexit

dm9000_drv_remove(struct platform_device *pdev)

{

struct net_device *ndev = platform_get_drvdata(pdev); //得到平台数据

/*设置平台数据为空*/

platform_set_drvdata(pdev, NULL);

/*注销驱动*/

unregister_netdev(ndev);

/*释放板资源*/

dm9000_release_board(pdev, (board_info_t *) netdev_priv(ndev));

/*释放网络设备结构体*/

free_netdev(ndev); /* free device structure */

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

return 0;

}

static struct platform_driver dm9000_driver = {

.driver = {

.name = "dm9000",

.owner = THIS_MODULE,

.pm = &dm9000_drv_pm_ops, //驱动电源管理操作

},

.probe = dm9000_probe,

.remove = __devexit_p(dm9000_drv_remove), /*__devexit_p宏为告知内核如果此驱动被编译成模块或者有热插拔事件时，此成员应被加载，否则此成员为NULL*/

};

static int __init

dm9000_init(void)

{

/*mini2440的dm9000网卡是接在bank4上的，所以要bank4进行时序设置*/

#if defined(CONFIG_ARCH_S3C2410)

/*获得总线宽度和等待控制寄存器地址*/

unsigned int oldval_bwscon = *(volatile unsigned int *)S3C2410_BWSCON;

/*获得bank4控制寄存器地址*/

unsigned int oldval_bankcon4 = *(volatile unsigned int *)S3C2410_BANKCON4;

/* 先清除BWSCON上的DW4为0，然后设置数据总线宽度为16位，启用BANK4的WAIT状态，启用BANK4的SRAM的写高低字节使能*/

*((volatile unsigned int *)S3C2410_BWSCON) =

(oldval_bwscon & ~(3<<16)) | S3C2410_BWSCON_DW4_16 | S3C2410_BWSCON_WS4 | S3C2410_BWSCON_ST4;

/* 设置PMC
– 页模式配置 为normal（ 1 data）

Tacp
– 页模式下的访问周期为 6 clocks

Tcah
– nGCSn后的地址保持时间为 4 clocks

Tcoh
– nOE后的片选保持时间为 1 clock

Tacc
– 访问周期为 14 clocks

Tcos
– nOE前的片选建立时间为 4 clocks

Tacs
– nGCSn前的地址建立时间为 0 clock

0 00 11 111 01 11 11 00

Tacs Tcos Tacc Tcoh Tcah Tacp PMC */

*((volatile unsigned int *)S3C2410_BANKCON4) = 0x1f7c;

#endif

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

/*注册平台驱动*/

return platform_driver_register(&dm9000_driver);

}

static void __exit

dm9000_cleanup(void)

{

/*注销平台驱动，将struct platform_driver dm9000_driver结构体注册到平台设备进行match匹配，匹配成功会调用probe函数往下进行*/

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");

MODULE_ALIAS("platform:dm9000");