platform_set_drvdata 和 platform_get_drvdata

    ndev是我们在probe函数中定义的局部变量，如果我想在其他地方使用它怎么办呢？ 这就需要把它保存起来。内核提供了这个方法，使用函数platform_set_drvdata()可以将ndev保存成平台总线设备的私有数据。以后再要使用它时只需调用platform_get_drvdata()就可以了。

 

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 */
        /*使用alloc_etherdev()来生成一个net_device结构体，并对其公有成员赋值*/
    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);
    memset(db, 0, sizeof(*db));

    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;
    }

    iosize = res_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 = res_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;
    }

    /* 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%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;
    }

    /* 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] = ior(db, i+DM9000_PAR);
    }

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

    //platform_set_drvdata()可以将ndev保存成平台总线设备的私有数据。以后再要使用它时只需调用
    //platform_get_drvdata()就可以了
    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;
}