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;
}