//__devinit 内核优化宏，编译器通过这些宏把代码优化放到合适的内存空间，宏__devinit标志设备初始化代码
static int __devinit
dm9000_probe(struct platform_device *pdev)
{
//这个platform_data是在板级配置文件中设置的
struct dm9000_plat_data *pdata = pdev->dev.platform_data;
struct board_info *db; /* Point a board information structure */
//网络设备驱动中两个重要结构体之一，另一个大名鼎鼎的结构体是skbuff
struct net_device *ndev;
const unsigned char *mac_src;
int ret = 0;
int iosize;
int i;
u32 id_val;
/* Init network device */
//初始化网络设备结构体net_device，最终是调用了函数alloc_netdev_mq，有时间我想好好分析下这个函数
ndev = alloc_etherdev(sizeof(struct board_info));
if (!ndev)
{
//实际上就是printk啦,我忍不住想说linux的一大特点，就是喜欢用满天飞的define给别人起新名字
dev_err(&pdev->dev, "could not allocate device.\n");
return -ENOMEM;
}
SET_NETDEV_DEV(ndev, &pdev->dev);
//最后还是printk。。。
dev_dbg(&pdev->dev, "dm9000_probe()\n");
/* setup board info structure */
//让结构体指针指向结构体ndev内的的某个xx(xx还没搞懂是哪个变量或者结构体)
db = netdev_priv(ndev);
db->dev = &pdev->dev;
db->ndev = ndev;
//初始化自旋锁
spin_lock_init(&db->lock);
//初始化互斥锁
mutex_init(&db->addr_lock);
INIT_DELAYED_WORK(&db->phy_poll, dm9000_poll_work);
//调用platform_get_resource获取资源填充结构体db,这个resource就是在板级配置
//文件中填充的那个struct resouce.
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;
}
//继续填充结构体db中....,获取一个设备irq，这个irq也是板级配置文件中设置的
//我的板上的两个dm9000分别分配了190,191.
db->irq_wake = platform_get_irq(pdev, 1);
if (db->irq_wake >= 0) {
dev_dbg(db->dev, "wakeup irq %d\n", db->irq_wake);
//注册中断函数dm9000_wol_interrupt，中断号为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;
}
}
}
//计算即将申请内存大小，这个大小是板级配置文件中struct resouce 中.end减去.tart再加1
//为什么要再加1?
iosize = resource_size(db->addr_res);
//我原来的理解是申请该大小内存区域，这个理解有偏差。
//该函数的任务是检查申请的资源是否可用，如果可用则申请成功，
//并标志为已经使用，其他驱动想再申请该资源时就会失败?
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;
}
//把db->addr_res->start开始，大小iosize，物理空间映射到虚拟地址空间
//这段虚拟地址空间开始地址是db->io_addr
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;
}
//以下这段程序操作与上类似，因为dm9000提供了地址和数据两个访问口，所以映射了两个。
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;
}
/* fill in parameters for net-dev structure */
ndev->base_addr = (unsigned long)db->io_addr;
ndev->irq = db->irq_res->start;
//设置dm9000位宽，根据板级配置文件中struct platform_data设置而定
//由此可见，linux内核移植很大一部分工作是驱动移植，是必须要在读懂驱动的前提上进行的
/* 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 */
//以下三个参数很少设置
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
//软件复位dm9000,实际上就是往dm9000寄存器NCR上写1
dm9000_reset(db);
//读dm9000id。如果读写时序正确，基本就能读到id.如果读id错误，
//要么是时序错了，要么就是硬件存在问题，我就遇到过这个坑爹的问题，
//如果硬件存在故障，这是驱动调试最痛苦痛苦的事情。
/* 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 */
//读dm9000寄存器CHIPR确定类型
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] = 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);
////把ndev保存为平台设备pdev的私有数据，并可以调用platform_get_drvdata获取该数据
platform_set_drvdata(pdev, ndev);
//注册一个网络设备
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;
out:
dev_err(db->dev, "not found (%d).\n", ret);
dm9000_release_board(pdev, db);
free_netdev(ndev);
return ret;
}