dm9000a驱动源码分析（一）

dm9000a框架原理图:

EEPROM Interface接口用于存放mac地址，InternalSRAM用于存放收发数据，MII部分把MAC部分与PHY部分连接起来通信，AUTO-MDIX用于自适应10/100M网络,在物理层上,MAC在PHY之下。 

由dm9000a驱动可知，dm9000a驱动是用platform模型编写的，分析一个驱动源码都是从模块加载函数module_init()开始，而dm9000a加载函数是module_init(dm9000_init).

继而调用：

static int __initdm9000_init(void){printk(KERN_INFO "%s Ethernet Driver, V%s\n", CARDNAME, DRV_VERSION);return platform_driver_register(&dm9000_driver);}

dm9000_driver结构体：

static struct platform_driver dm9000_driver = {.driver= {.name    = "dm9000",//名字.owner = THIS_MODULE,},.probe   = dm9000_probe,//模块加载后，调用probe函数.remove  = __devexit_p(dm9000_drv_remove),.suspend = dm9000_drv_suspend,.resume  = dm9000_drv_resume,};

模块加载之后，调用probe函数，如下：

/* * Search DM9000 board, allocate space and register it */static int __devinitdm9000_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;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-upwritel( (readl(extint0) & ~(0xf << 28)) | (0x4 << 28), extint0); //rising edgewritel( (readl(intmsk))  & ~0x80, intmsk);    /* ------------------------------------------------------------------------ *//* Init network device *//* 分配eth网卡资源，私有数据区保存board_info*/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 初始化为0*/db = ndev->priv;memset(db, 0, sizeof(*db));db->dev = &pdev->dev;db->ndev = ndev;/*初始化spinlock*/spin_lock_init(&db->lock);mutex_init(&db->addr_lock);/*提交一个任务给一个工作队列，你需要填充一个work_struct结构db->phy_poll*/ INIT_DELAYED_WORK(&db->phy_poll, dm9000_poll_work);/*获取IO内存和中断资源*/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;}/*映射到内核，并获得IO内存的虚拟地址，ioremap完成页表的建立，不同于vmalloc，但是，它实际上不分配内存*/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 *//*获得网络设备的基地址*/ndev->base_addr = (unsigned long)db->io_addr;/*获得网络设备的中断号*/ndev->irq= db->irq_res->start;/* ensure at least we have a default set of IO routines *//*设置默认的IO函数*/ dm9000_set_io(db, iosize);/*如果平台数据不为空 */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_POLLdb->flags |= DM9000_PLATF_SIMPLE_PHY;#endif/*根据board info信息，复位DM9000芯片*/dm9000_reset(db);/*读取Vendor ID Register,Product ID Register中的值，与0x90000A46比较，如果相等，则说明是DM9000*//* 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);} /*芯片的ID获取失败，驱动不匹配*/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 *//*读取Chip Revision Register中的值*/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 *//*设置部分net_device字段*/ether_setup(ndev);ndev->open = &dm9000_open;ndev->hard_start_xmit    = &dm9000_start_xmit;ndev->tx_timeout         = &dm9000_timeout;ndev->watchdog_timeo = msecs_to_jiffies(watchdog);ndev->stop = &dm9000_stop;ndev->set_multicast_list = &dm9000_hash_table;/*对ethtool支持的相关声明可在<linux/ethtool.h>中找到。它的核心是一个ethtool_ops类型的结构，里边包含一个全部的24个不同的方法来支持ethtool*/ndev->ethtool_ops = &dm9000_ethtool_ops;ndev->do_ioctl = &dm9000_ioctl;#ifdef CONFIG_NET_POLL_CONTROLLERndev->poll_controller = &dm9000_poll_controller;#endifdb->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地址的源是eeprom*/ 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);/*如果从eeprom中读取的地址无效，并且私有数据不为空，从platform_device的私有数据中获取dev_addr*/ if (!is_valid_ether_addr(ndev->dev_addr) && pdata != NULL) {mac_src = "platform data";memcpy(ndev->dev_addr, pdata->dev_addr, 6);}/*如果地址依然无效，从PAR:物理地址(MAC)寄存器(Physical Address Register)中读取*/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);   // by baindev->dev_addr[i] = ne_def_eth_mac_addr[i];}/*查看以太网网卡设备地址是否有效*/if (!is_valid_ether_addr(ndev->dev_addr))dev_warn(db->dev, "%s: Invalid ethernet MAC address. Please " "set using ifconfig\n", ndev->name);/*将ndev保存到pdev->dev->driver_data中*/platform_set_drvdata(pdev, ndev); /*一切都初始化好后，注册网络设备*/ret = register_netdev(ndev);if (ret == 0) {DECLARE_MAC_BUF(mac);printk(KERN_INFO "%s: dm9000%c at %p,%p IRQ %d MAC: %s (%s)\n",       ndev->name, dm9000_type_to_char(db->type),       db->io_addr, db->io_data, ndev->irq,       print_mac(mac, ndev->dev_addr), mac_src);}return 0;out:dev_err(db->dev, "not found (%d).\n", ret);/*失败时,释放资源*/dm9000_release_board(pdev, db);free_netdev(ndev);return ret;}