三、网络设备驱动分析
我们先看看dm9000.c驱动的模块加载函数
| static struct platform_driver dm9000_driver = { .driver = { .name = "dm9000", //驱动名 .owner = THIS_MODULE, .pm = &dm9000_drv_pm_ops, //电源相关操作 }, .probe = dm9000_probe, //探测函数 .remove = __devexit_p(dm9000_drv_remove), }; static int __init dm9000_init(void) { #if defined(CONFIG_ARCH_S3C2410) //调整DM9000所用的位宽寄存器 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%s\n", CARDNAME, DRV_VERSION); return platform_driver_register(&dm9000_driver); //注册驱动 } |
下面我们重点关注下probe探测函数
| static int __devinit dm9000_probe(struct platform_device *pdev) { struct dm9000_plat_data *pdata = pdev->dev.platform_data; //获取平台数据 struct board_info *db; //网卡私有数据 struct net_device *ndev; //网络设备结构体 const unsigned char *mac_src; int ret = 0; int iosize; int i; u32 id_val; //分配并初始化net_device，把board_info作为net_device的私有数据 ndev = alloc_etherdev(sizeof(struct board_info)); if (!ndev) { dev_err(&pdev->dev, "could not allocate device.\n"); return -ENOMEM; } //设置继承关系，使pdev->dev作为ndev的parent SET_NETDEV_DEV(ndev, &pdev->dev); dev_dbg(&pdev->dev, "dm9000_probe()\n"); db = netdev_priv(ndev); //获取私有数据 db->dev = &pdev->dev; //设置父设备 db->ndev = ndev; spin_lock_init(&db->lock); //初始化锁 mutex_init(&db->addr_lock); //初始化互斥锁 INIT_DELAYED_WORK(&db->phy_poll, dm9000_poll_work); //初始化工作队列 db->addr_res = platform_get_resource(pdev, IORESOURCE_MEM, 0); //获取地址寄存器 db->data_res = platform_get_resource(pdev, IORESOURCE_MEM, 1); //获取数据寄存器 db->irq_res = platform_get_resource(pdev, IORESOURCE_IRQ, 0); //获取中断号 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 = resource_size(db->addr_res); //地址寄存器大小 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); //物理地址映射为虚拟地址 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); //数据寄存器 if (db->io_data == NULL) { dev_err(db->dev, "failed to ioremap data reg\n"); ret = -EINVAL; goto out; } ndev->base_addr = (unsigned long)db->io_addr; //地址寄存器 ndev->irq = db->irq_res->start; //中断号 dm9000_set_io(db, iosize); //根据DM9000数据位宽设置读写数据帧的函数指针 if (pdata != NULL) { if (pdata->flags & DM9000_PLATF_8BITONLY) dm9000_set_io(db, 1); if (pdata->flags & DM9000_PLATF_16BITONLY) //根据平台数据重新设置数据位宽 dm9000_set_io(db, 2); if (pdata->flags & DM9000_PLATF_32BITONLY) dm9000_set_io(db, 4); if (pdata->inblk != NULL) //如果平台数据定义了这些函数，则优先使用这些函数 db->inblk = pdata->inblk; //输入 if (pdata->outblk != NULL) db->outblk = pdata->outblk; //输出 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); //对DM9000进行复位 for (i = 0; i < 8; i++) { //读芯片ID号 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) { //判断是否为0x90000A46 dev_err(db->dev, "wrong id: 0x%08x\n", id_val); ret = -ENODEV; goto out; } id_val = ior(db, DM9000_CHIPR); dev_dbg(db->dev, "dm9000 revision 0x%02x\n", id_val); switch (id_val) { //设置DM000的具体类型 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; } 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); //对net_device中部分成员进行初始化 ndev->netdev_ops = &dm9000_netdev_ops; // 网络操作方法 ndev->watchdog_timeo = msecs_to_jiffies(watchdog); //看门狗时间 ndev->ethtool_ops = &dm9000_ethtool_ops; //使用户空间支持ethtool这一工具 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) //从E2PROM中读取MAC地址 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); //从平台数据中读取MAC地址 } if (!is_valid_ether_addr(ndev->dev_addr)) { mac_src = "chip"; for (i = 0; i < 6; i++) ndev->dev_addr[i] = ior(db, i+DM9000_PAR); } memcpy(ndev->dev_addr, "\x08\x90\x90\x90\x90\x90", 6); //直接给软MAC地址 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(pdev, ndev); //将net_device作为平台数据 ret = register_netdev(ndev); //注册net_device 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; } |
