ARM-Linux驱动--DM9000网卡驱动分析（二）

硬件平台：FL2440（s3c2440）

内核版本：2.6.35

主机平台：Ubuntu 11.04

内核版本：2.6.39

原创作品，转载请标明出处http://blog.csdn.net/yming0221/article/details/6612623

下面开始分析具体的代码，这里由于使DM9000驱动更容易理解，在不影响基本的功能的前提下，这里将尽可能的简化该驱动（如：去掉该驱动中支持电源管理的功能）

分析该驱动

1、首先看一下该驱动的平台设备驱动的结构体定义

/*平台设备驱动的结构体定义 *在该结构体中可以定义有关Power Management的管理函数 *该驱动中将其省略，侧重分析dm9000的基本原理 */ static struct platform_driver dm9000_driver = { .driver = { .name = "dm9000",/* 该名称和系统初始化中，平台设备的名称一致 */ .owner = THIS_MODULE, }, .probe = dm9000_probe,/* 资源探测函数 */ .remove = __devexit_p(dm9000_drv_remove),/* 设备移除函数 */ }; 在执行insmod后内核自动那个执行下面的函数
static int __init dm9000_init(void) { printk(KERN_INFO "%s Ethernet Driver, V%s\n", CARDNAME, DRV_VERSION); return platform_driver_register(&dm9000_driver); }

调用函数platform_driver_register()函数注册驱动。

3、自动执行驱动的probe函数，进行资源的探测和申请资源。

其中BWSCON为总线宽度 等待控制寄存器

其中第[19:18]位的作用如下

下面函数中将两位设置为11，也就是WAIT使能，bank4使用UB/LB。

alloc_etherdev()函数分配一个网络设备的结构体，原型在include/linux/etherdevice.h

原型如下：

extern struct net_device *alloc_etherdev_mq(int sizeof_priv, unsigned int queue_count); #define alloc_etherdev(sizeof_priv) alloc_etherdev_mq(sizeof_priv, 1) 该函数中需要将获得的资源信息存储在一个结构体中，定义如下：

/* Structure/enum declaration ------------------------------- */ typedef struct board_info { void __iomem *io_addr; /* Register I/O base address */ void __iomem *io_data; /* Data I/O address */ u16 irq; /* IRQ */ u16 tx_pkt_cnt; u16 queue_pkt_len; u16 queue_start_addr; u16 queue_ip_summed; u16 dbug_cnt; u8 io_mode; /* 0:word, 2:byte */ u8 phy_addr; u8 imr_all; unsigned int flags; unsigned int in_suspend :1; unsigned int wake_supported :1; int debug_level; enum dm9000_type type; void (*inblk)(void __iomem *port, void *data, int length); void (*outblk)(void __iomem *port, void *data, int length); void (*dumpblk)(void __iomem *port, int length); struct device *dev; /* parent device */ struct resource *addr_res; /* resources found */ struct resource *data_res; struct resource *addr_req; /* resources requested */ struct resource *data_req; struct resource *irq_res; int irq_wake; struct mutex addr_lock; /* phy and eeprom access lock */ struct delayed_work phy_poll; struct net_device *ndev; spinlock_t lock; struct mii_if_info mii; u32 msg_enable; u32 wake_state; int rx_csum; int can_csum; int ip_summed; } board_info_t;

下面是probe函数，

其中有个函数db = netdev_priv(ndev)

该函数实际上是返回网卡私有成员的数据结构地址

函数如下，定义在include/linux/net_device.h中

static inline void *netdev_priv(const struct net_device *dev) { return (char *)dev + ALIGN(sizeof(struct net_device), NETDEV_ALIGN); }

/* * 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;/* 网络设备 */ 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};/* 设定默认的mac地址 */ static void *bwscon;/* 保存ioremap返回的寄存器的虚拟地址，下同 */ static void *gpfcon; static void *extint0; static void *intmsk; /*Added by yan*/ #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);/* 将BWSCON寄存器[19:18]设置为11 */ writel( (readl(gpfcon) & ~(0x3 << 14)) | (0x2 << 14), gpfcon); /* 设置GPF寄存器 */ writel( readl(gpfcon) | (0x1 << 7), gpfcon); // Disable pull-up，不使能上拉 writel( (readl(extint0) & ~(0xf << 28)) | (0x4 << 28), extint0); //rising edge，设置上升沿触发中断 writel( (readl(intmsk)) & ~0x80, intmsk);/* 设置中断屏蔽寄存器 */ /*End of add*/ /* Init network device */ /* 使用alloc_etherdev()函数分配一个网络设备的结构体，原型在include/linux/etherdevice.h */ ndev = alloc_etherdev(sizeof(struct board_info)); if (!ndev) { dev_err(&pdev->dev, "could not allocate device.\n"); return -ENOMEM; } /*通过SET_NETDEV_DEV(netdev, &pdev->dev)宏设置net_device.device->parent为当前的pci_device->device *(这儿net_device包含的是device结构，而不是指针）。这样，就建立起了net_device到device的联系。 */ SET_NETDEV_DEV(ndev, &pdev->dev); dev_dbg(&pdev->dev, "dm9000_probe()\n"); /* setup board info structure */ /* 下面都是设置board_info结构体 */ db = netdev_priv(ndev);/* 返回dev->priv的地址 */ 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; } db->irq_wake = platform_get_irq(pdev, 1); if (db->irq_wake >= 0) { dev_dbg(db->dev, "wakeup irq %d\n", db->irq_wake); ret = request_irq(db->irq_wake, dm9000_wol_interrupt, IRQF_SHARED, dev_name(db->dev), ndev); if (ret) { dev_err(db->dev, "cannot get wakeup irq (%d)\n", ret); } else { /* test to see if irq is really wakeup capable */ ret = set_irq_wake(db->irq_wake, 1); if (ret) { dev_err(db->dev, "irq %d cannot set wakeup (%d)\n", db->irq_wake, ret); ret = 0; } else { set_irq_wake(db->irq_wake, 0); db->wake_supported = 1; } } } 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; } 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 = 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); if (db->io_data == NULL) { dev_err(db->dev, "failed to ioremap data reg\n"); ret = -EINVAL; goto out; } /* 设置结构体board_info结束 */ /* fill in parameters for net-dev structure */ ndev->base_addr = (unsigned long)db->io_addr;/* 设置网络设备的地址 */ ndev->irq = db->irq_res->start;/* 设置网络设备的中断资源地址 */ /* 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 */ /*根据pdev->dev.platform_data的信息判断IO的宽度并设置相应的宽度*/ 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);/* 复位 */ /* 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; } /* 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->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] = ne_def_eth_mac_addr[i]; } 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pdev->dev->driver_data为ndev，保存成平台设备总线上的数据，以后使用只需platform_get_drvdata()即可*/ platform_set_drvdata(pdev, ndev); /* 注册该网络设备 */ 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; /* 异常处理 */ out: dev_err(db->dev, "not found (%d).\n", ret); dm9000_release_board(pdev, db); free_netdev(ndev); return ret; } 这样，最后完成了网络设备的数据保存到总线上，将网络设备注册到内核。

4、设备的移除函数

/* 该函数是将设备从内核中移除，释放资源，在移除设备驱动时执行 */ static int __devexit dm9000_drv_remove(struct platform_device *pdev) { struct net_device *ndev = platform_get_drvdata(pdev);/* 从总线获取probe函数保存到总线的设备信息 */ platform_set_drvdata(pdev, NULL);/* 释放pdev资源 */ unregister_netdev(ndev);/* 解除网络设备 */ dm9000_release_board(pdev, (board_info_t *) netdev_priv(ndev));/* 释放该设备申请的IO资源 */ free_netdev(ndev); /* free device structure */ dev_dbg(&pdev->dev, "released and freed device\n"); return 0; }

更多见ARM-Linux驱动--DM9000网卡驱动分析（一）

ARM-Linux驱动--DM9000网卡驱动分析（三）