WRTNode(MT7620n)USB启动总结

一.改动mt7620.dtsi，去掉默认的bootargs，kernel_menuconfig取消buildin的command line

二.kernel_menuconfig增加scsi驱动。USB Storage，Ext4文件系统，设置USB驱动有个关键的地方，要打开：

<*>     Generic EHCI driver for a platform device

三.set bootargs root=8:2 rootdelay=5 rootfstype=ext4 rw console=ttyS0,57600注意：rootdelay非常关键

四.全然关闭MTD驱动。须要改动两处：

1.从MTD中获取MAC地址

代码位于drivers/of/of_net.c

int of_get_mac_address_mtd(struct device_node *np, void *mac)

{

    struct device_node *mtd_np = NULL;

    size_t retlen;

    int size, ret;

    struct mtd_info *mtd;

    const char *part;

    const __be32 *list;

    phandle phandle;

    list = of_get_property(np, "mtd-mac-address", &size);

    if (!list || (size != (2 * sizeof(*list))))

        return -ENOENT;

    phandle = be32_to_cpup(list++);

    if (phandle)

        mtd_np = of_find_node_by_phandle(phandle);

    if (!mtd_np)

        return -ENOENT;

    part = of_get_property(mtd_np, "label", NULL);

    if (!part)

        part = mtd_np->name;

    mtd = get_mtd_device_nm(part);

    if (IS_ERR(mtd))

        return PTR_ERR(mtd);

    ret = mtd_read(mtd, be32_to_cpup(list), 6, &retlen, (u_char *) mac);

    put_mtd_device(mtd);

    return ret;

}

当中MTD中的mac地址位置定义在WRTNode.dts文件里

ethernet@10100000 {

    mtd-mac-address = <&factory 0x4>;

    ralink,port-map = "wllll";

};

factory区（mtdblock3）内容例如以下：

我们能够看到。factory偏移4的mac地址是00:0C:43:76:20:A0

因为关闭了MTD驱动，如今的思路：通过bootargs来传递mac地址。

改动of_net.c代码为：

#ifdef CONFIG_MTD

int of_get_mac_address_mtd(struct device_node *np, void *mac)

{

    // 原始代码，从factory偏移4中获取mac地址 

}

#else // #not define CONFIG_MTD

// manfeel , mod to support cmdline mac address

char mac_addr[ETH_ALEN];

static int __init eth_addr_setup(char *str)

{

    int i;

    if(str == NULL)

        return 0;

    for(i = 0; i < ETH_ALEN; i++)

        mac_addr[i] = simple_strtol(&str[i*3], (char **)NULL, 16);

    return 1;

}

/* Get MAC address from kernel boot parameter eth=AA:BB:CC:DD:EE:FF */

__setup("eth=", eth_addr_setup);

int of_get_mac_address_mtd(struct device_node *np, void *mac)

{

    int i;

    for(i = 0; i < ETH_ALEN; i++)

        ((u_char *) mac)[i] = mac_addr[i];

    return 1;

}

#endif

于是，bootargs变成了：root=8:2 rootdelay=5 rootfstype=ext4 rw eth=${ethaddr} console=ttyS0,57600

2.从MTD中获取wifi參数

因为WRTNode使用了lintel编译好的ko格式的wifi驱动。无法改动。所以找到了“大茶园丁”大侠的代码，感谢他;)

“大茶”採取的是kernelPackage的方式。故rt2860的代码位于：build_dir/target-mipsel_24kec+dsp_uClibc-0.9.33.2/linux-ramips_mt7620n/rt2860v2-r2714

读取MTD中的wifi配置的代码位于：rt2860v2/os/linux/rt_flash.c中。改动例如以下：

#include <linux/module.h>

#include <linux/types.h>

#include <linux/init.h>

#include <linux/kernel.h>

#include <linux/version.h>

#include <linux/err.h>

#include <linux/slab.h>

#include <linux/delay.h>

#include <linux/sched.h>

#include <linux/backing-dev.h>

#include <linux/compat.h>

#include <linux/mount.h>

//#include <linux/mtd/mtd.h>

//#include <linux/mtd/map.h>

//#include <linux/mtd/concat.h>

//#include <linux/mtd/partitions.h>

#include <linux/fs.h>

#include <linux/string.h>

#include <linux/mm.h>

#include <linux/syscalls.h>

#include <asm/unistd.h>

#include <asm/uaccess.h>

#define MY_FILE "/etc/config/eeprom"

struct proc_dir_entry *procRegDir;

/*

 * Flash API: ra_mtd_read, ra_mtd_write

 * Arguments:

 *   - num: specific the mtd number

 *   - to/from: the offset to read from or written to

 *   - len: length

 *   - buf: data to be read/written

 * Returns:

 *   - return -errno if failed

 *   - return the number of bytes read/written if successed

 */

int ra_mtd_write_nm(char *name, loff_t to, size_t len, const u_char *buf)

{

    int ret = -1;

    pr_info("NOT implement : mtd_write to %X len = %X\n", to , len);

    return ret;

}

int ra_mtd_read_nm(char *name, loff_t from, size_t len, u_char *buf)

{

    int ret;

    size_t rdlen = 0;

    struct mtd_info *mtd;

    pr_info("<=-=- mtd_read(%s,in file!) from %d len = %d\n", name, from , len);

    pr_info("begin to read factory file\n");

    struct file *file = NULL;

    mm_segment_t old_fs;    

    if(file == NULL)

        file = filp_open(MY_FILE, O_RDWR, 0644);

        if (IS_ERR(file)) {

            printk("error occured while opening file %s, exiting...\n", MY_FILE);

            return 0;

        }

     old_fs = get_fs();

     set_fs(KERNEL_DS);

     file->f_pos = from;

     rdlen = file->f_op->read(file, (char *)buf, len == 0 ?

0x400 : len, &file->f_pos);

     set_fs(old_fs);

     filp_close(file, NULL);  

     file = NULL;

     ret = 1;

    pr_info("mtd_read rdlen = %X\n",rdlen);

    if (rdlen != len)

        printk("warning: ra_mtd_read_nm: rdlen is not equal to len\n");

    return ret;

}

EXPORT_SYMBOL(ra_mtd_write_nm);

EXPORT_SYMBOL(ra_mtd_read_nm);

EXPORT_SYMBOL(procRegDir);

MODULE_AUTHOR("Manfeel <manfeel@foxmail.com>");

MODULE_DESCRIPTION("Ralink APSoC Flash Map");

MODULE_LICENSE("GPL");

内核驱动中读取/etc/config/eeprom文件的方式来实现，不符合kernel工作组的规范。后期想改成module parameter的方式。在insmod中，将eeprom内容通过数组參数的方式传递到内核驱动。