2021年10月25日 | mini2440上dm9000驱动分析（一）

先提个问题：看到有的网卡是连在ISA总线或者是PCI总线上的，那在mini2440上dm9000和CPU是直接相连的，这个算是什么总线？ 没弄明白这个问题

首先是平台设备的register和unregister. 

static int __init

dm9000_init(void)

{

#if defined(CONFIG_ARCH_S3C2410)

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

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

*((volatile unsigned int *)S3C2410_BWSCON) =

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

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

#endif

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

return platform_driver_register(&dm9000_driver);

}

static void __exit

dm9000_cleanup(void)

{

platform_driver_unregister(&dm9000_driver);

}

dm9000_init中，#if defined 中间的内容是什么意思我不清楚。以上两个函数就是平台设备的注册和取消。

一、下面分析dm9000_probe函数，这个是平台设备主要的初始化函数

/*

 * 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;

const unsigned char *mac_src;

int ret = 0;

int iosize;

int i;

u32 id_val;

/* Init network device */

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");

/* setup board info structure */

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;

}

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;

}

/* 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;

db->flags = pdata->flags;

}

#ifdef CONFIG_DM9000_FORCE_SIMPLE_PHY_POLL

db->flags |= DM9000_PLATF_SIMPLE_PHY;

#endif

dm9000_reset(db);

/* 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%08xn", id_val);

}

if (id_val != DM9000_ID) {

dev_err(db->dev, "wrong id: 0x%08xn", 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%02xn", 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 DM9000En", 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->msg_enable       = 0xffff;

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] = ior(db, i+DM9000_PAR);

}

memcpy(ndev->dev_addr, "x08x90x90x90x90x90", 6);

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;

}

上面这段代码中， 有几个地方说明一下：

1.  struct dm9000_plat_data *pdata = pdev->dev.platform_data;这个 pdata得到的内容是在文件   arch/arm/mach-s3c2440/mach-mini2440.c 中定义的，定义如下

/* DM9000AEP 10/100 ethernet controller */

#define MACH_MINI2440_DM9K_BASE (S3C2410_CS4 + 0x300)

static struct resource mini2440_dm9k_resource[] = {

        [0] = {

                .start = MACH_MINI2440_DM9K_BASE,

                .end   = MACH_MINI2440_DM9K_BASE + 3,

                .flags = IORESOURCE_MEM

        },

        [1] = {

                .start = MACH_MINI2440_DM9K_BASE + 4,

                .end   = MACH_MINI2440_DM9K_BASE + 7,

                .flags = IORESOURCE_MEM

        },

        [2] = {

                .start = IRQ_EINT7,

                .end   = IRQ_EINT7,

                .flags = IORESOURCE_IRQ | IORESOURCE_IRQ_HIGHEDGE,

        }

};

/*

 *  * The DM9000 has no eeprom, and it's MAC address is set by

 *   * the bootloader before starting the kernel.

 *    */

static struct dm9000_plat_data mini2440_dm9k_pdata = {

        .flags          = (DM9000_PLATF_16BITONLY | DM9000_PLATF_NO_EEPROM),

};

static struct platform_device mini2440_device_eth = {

        .name           = "dm9000",

        .id             = -1,

        .num_resources  = ARRAY_SIZE(mini2440_dm9k_resource),

        .resource       = mini2440_dm9k_resource,

        .dev            = {

                .platform_data  = &mini2440_dm9k_pdata,

        },

};

从上面的27行，就可以知道pdata的值是什么。驱动移植时，一般就是修改mach-mini2440.c这个文件，当然也有些版本将dm9000的resource包含在文件 archarmplat-s3c24xx这个文件中，我觉得这两个文件应该是特殊与一般的关系，最通用的resource就定义在plat-s3c24xx文件中，而因开发板各异的resource就包含在mach-mini2440.c文件中。

2.  probe函数第23行中， SET_NETDEV_DEV(ndev, &pdev->dev)  这个宏展开之后， /* Set the sysfs physical device reference for the network logical device * if set prior to registration will cause a symlink during initialization. */#define SET_NETDEV_DEV(net, pdev) ((net)->dev.parent = (pdev))应该是与sysfs有关，但是目前不是很理解这句话的作用。当把这句话去掉之后，驱动是可以正常运行的，唯一的区别是去掉之后，目录/sys/devices/platform/dm9000/net 将不存在。sysfs的用法还没有彻底弄明白。