在学习Mini2440裸机程序时，我们介绍过关于DM9000网卡的相关知识，包括电路图、以及DM9000寄存器等信息。具体可以参考Mini2440裸机开发之DM9000。
本节对之前已经介绍过的知识不会再进行重复介绍。这一节我们将直入主题，介绍如何移植DM9000网卡驱动。
一、platform设备注册(dm9000)
在刚学习驱动移植的时候，我们为了使用nfs作为根文件系统，我们在linux驱动移植-DM9000网卡驱动小节介绍了DM9000网卡驱动的移植，但是那时候我们仅仅是移植，并为对源码进行深入研究。
DM9000网卡设备驱动，其采用的也是platform设备驱动模型。
1.1 smdk2440_device_eth
我们定位到arch/arm/mach-s3c24xx/mach-smdk2440.c文件，在该文件中我们引入了dm9000.h头文件：
#include <linux/dm9000.h>
定义了DM9000网卡设备的物理基地址：
#define MACH_SMDK2440_DM9K_BASE (S3C2410_CS4 + 0x300) # S3C2410_CS4 = 0X20000000
定义了网卡platform设备smdk2440_device_eth：
/* DM9000AEP 10/100 ethernet controller */
static struct resource smdk2440_dm9k_resource[] = {
[0] = DEFINE_RES_MEM(MACH_SMDK2440_DM9K_BASE, 4),
[1] = DEFINE_RES_MEM(MACH_SMDK2440_DM9K_BASE + 4, 4),
[2] = DEFINE_RES_NAMED(IRQ_EINT7, 1, NULL, IORESOURCE_IRQ
| IORESOURCE_IRQ_HIGHEDGE),
};
/*
* The DM9000 has no eeprom, and it's MAC address is set by
* the bootloader before starting the kernel.
*/
static struct dm9000_plat_data smdk2440_dm9k_pdata = {
.flags = (DM9000_PLATF_16BITONLY | DM9000_PLATF_NO_EEPROM),
};
static struct platform_device smdk2440_device_eth = {
.name = "dm9000",
.id = -1,
.num_resources = ARRAY_SIZE(smdk2440_dm9k_resource),
.resource = smdk2440_dm9k_resource,
.dev = {
.platform_data = &smdk2440_dm9k_pdata,
},
};
1.2 smdk2440_machine_init
linux内核启动的时候会根据uboot中设置的机器id执行相应的初始化工作，比如.init_machine、.init_irq，我们首先定位到arch/arm/mach-s3c24xx/mach-smdk2440.c：
MACHINE_START(S3C2440, "SMDK2440")
/* Maintainer: Ben Dooks <[email protected]> */
.atag_offset = 0x100,
.init_irq = s3c2440_init_irq,
.map_io = smdk2440_map_io,
.init_machine = smdk2440_machine_init,
.init_time = smdk2440_init_time,
MACHINE_END
重点关注init_machine，init_machine中保存的是开发板资源注册的初始化代码。
static void __init smdk2440_machine_init(void)
{
s3c24xx_fb_set_platdata(&smdk2440_fb_info);
s3c_i2c0_set_platdata(NULL);
platform_add_devices(smdk2440_devices, ARRAY_SIZE(smdk2440_devices)); // s3c2440若干个platform设备注册 usb host controller、lcd、wdt等
smdk_machine_init(); // s3c24x0系列若干个platform设备注册（通用）
}
这里利用platform_add_devices进行若干个platform设备的注册，该函数还是通过调用platform_device_register实现platform设备注册.
static struct platform_device *smdk2440_devices[] __initdata = {
&s3c_device_ohci,
&s3c_device_lcd,
&s3c_device_wdt,
&s3c_device_i2c0,
&s3c_device_iis,
&smdk2440_device_eth,
};
二、platform驱动注册dm9000)
我们需要配置内核支持DM9000网卡驱动：
Device Drivers --->
[*] Network device support -->
[*] Ethernet driver support -->
[*] DM9000 support
这样我们内核才会支持DM9000网卡驱动。配置了DM9000 support之后，配置文件.config中会包含如下项：
# CONFIG_GEMINI_ETHERNET is not set CONFIG_DM9000=y
当我们使用make uImage编译内核时会将dm9000.o编译进内核：
drivers/net/ethernet/davicom/Makefile:6:obj-$(CONFIG_DM9000) += dm9000.o
dm9000.c文件位于drivers/net/ethernet/davicom目录下。
2.1 入口和出口函数
我们在dm9000.c文件定位到驱动模块的入口和出口：
module_platform_driver(dm9000_driver);
module_platform_driver宏展开后本质上就是：
module_init(dm9000_driver_init);
module_exit(dm9000_driver_exit);
static int __init dm9000_driver_init(void)
{
platform_driver_register(dm9000_driver);
}
static void __exit dm9000_driver_exit(void)
{
platform_driver_unregister(dm9000_driver);
}
看到这里是不是有点意外，这里是通过platform_driver_register函数注册了一个platform驱动。
在plaftrom总线设备驱动模型中，我们知道当内核中有platform设备platform驱动匹配，会调用到platform_driver里的成员.probe，在这里就是dm9000_probe函数。
static struct platform_driver dm9000_driver = {
.driver = {
.name = "dm9000",
.pm = &dm9000_drv_pm_ops,
.of_match_table = of_match_ptr(dm9000_of_matches),
},
.probe = dm9000_probe,
.remove = dm9000_drv_remove,
};
2.2 dm9000_probe
/*
* Search DM9000 board, allocate space and register it
*/
static int
dm9000_probe(struct platform_device *pdev)
{
struct dm9000_plat_data *pdata = dev_get_platdata(&pdev->dev); // pdev->dev.platform_data
struct board_info *db; /* Point a board information structure */
struct net_device *ndev;
struct device *dev = &pdev->dev;
const unsigned char *mac_src;
int ret = 0;
int iosize;
int i;
u32 id_val;
int reset_gpios;
enum of_gpio_flags flags;
struct regulator *power;
bool inv_mac_addr = false;
power = devm_regulator_get(dev, "vcc");
if (IS_ERR(power)) {
if (PTR_ERR(power) == -EPROBE_DEFER)
return -EPROBE_DEFER;
dev_dbg(dev, "no regulator provided\n");
} else {
ret = regulator_enable(power);
if (ret != 0) {
dev_err(dev,
"Failed to enable power regulator: %d\n", ret);
return ret;
}
dev_dbg(dev, "regulator enabled\n");
}
reset_gpios = of_get_named_gpio_flags(dev->of_node, "reset-gpios", 0,
&flags);
if (gpio_is_valid(reset_gpios)) {
ret = devm_gpio_request_one(dev, reset_gpios, flags,
"dm9000_reset");
if (ret) {
dev_err(dev, "failed to request reset gpio %d: %d\n",
reset_gpios, ret);
return -ENODEV;
}
/* According to manual PWRST# Low Period Min 1ms */
msleep(2);
gpio_set_value(reset_gpios, 1);
/* Needs 3ms to read eeprom when PWRST is deasserted */
msleep(4);
}
if (!pdata) {
pdata = dm9000_parse_dt(&pdev->dev);
if (IS_ERR(pdata))
return PTR_ERR(pdata);
}
/* Init network device */
ndev = alloc_etherdev(sizeof(struct board_info));
if (!ndev)
return -ENOMEM;
SET_NETDEV_DEV(ndev, &pdev->dev);
dev_dbg(&pdev->dev, "dm9000_probe()\n");
/* setup board info structure */
db = netdev_priv(ndev);
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);
if (!db->addr_res || !db->data_res) {
dev_err(db->dev, "insufficient resources addr=%p data=%p\n",
db->addr_res, db->data_res);
ret = -ENOENT;
goto out;
}
ndev->irq = platform_get_irq(pdev, 0);
if (ndev->irq < 0) {
dev_err(db->dev, "interrupt resource unavailable: %d\n",
ndev->irq);
ret = ndev->irq;
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 = irq_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 {
irq_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;
}
/* fill in parameters for net-dev structure */
ndev->base_addr = (unsigned long)db->io_addr;
/* 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 */
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);
/* 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) {
ndev->hw_features = NETIF_F_RXCSUM | NETIF_F_IP_CSUM;
ndev->features |= ndev->hw_features;
}
/* from this point we assume that we have found a DM9000 */
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, ETH_ALEN);
}
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)) {
inv_mac_addr = true;
eth_hw_addr_random(ndev);
mac_src = "random";
}
platform_set_drvdata(pdev, ndev);
ret = register_netdev(ndev);
if (ret == 0) {
if (inv_mac_addr)
dev_warn(db->dev, "%s: Invalid ethernet MAC address. Please set using ip\n",
ndev->name);
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;
}
这段代码属实有点长了，让人一眼看过去，就有点想放弃去读的想法，既然都学习到了这一步，我们还是耐着性去分析吧。
三、代码下载
Young / s3c2440_project[drivers]
参考文章：
[1] 移植DM900C网卡驱动
[2]二十、Linux驱动之移植DM9000C网卡驱动（上）
[3]二十一、Linux驱动之移植DM9000C网卡驱动（下）
标签：platform,DM9000,db,dev,网卡,dm9000,驱动,ndev From： https://www.cnblogs.com/zyly/p/17087631.html