1. 内核配置

内核启用USB Gadget，使用fs配置usb device信息。

Device Drivers  ---> 
     [*]   USB support  --->
         <*>   USB Gadget Support  --->
    		  <*>   USB Gadget functions configurable through configfs 
              [*]     HID function
              <*>   USB Gadget precomposed configurations (Function Filesystem)  --->

2. 设备配置

HID设备配置如下，需要将该shell函数添加到启动脚本中，其中的相关描述符配置自行根据USB 协议配置，然后调用该脚本。

shell 复制代码

usb_hid_device_config()
{
    if [ -d /sys/kernel/config/usb_gadget/ ] ; then
        ######USB HID Device config######
        cd /sys/kernel/config/usb_gadget/
        mkdir -p isticktoit
        cd isticktoit
        echo 0x0483 > idVendor
        echo 0x5710 > idProduct # STM32
        echo 0x0215 > bcdDevice # v1.0.0
        echo 0x0200 > bcdUSB # USB2
        mkdir -p strings/0x409
        echo "xxxxxx" > strings/0x409/serialnumber
        echo "xxxxxx" > strings/0x409/manufacturer
        echo "xxxxxx" > strings/0x409/product
        mkdir -p configs/c.1/strings/0x409
        echo "HID_CONFIGUE" > configs/c.1/strings/0x409/configuration
        echo 2 > configs/c.1/MaxPower
        
        # Add functions here
        mkdir -p functions/hid.usb0
        echo 0 > functions/hid.usb0/protocol
        echo 0 > functions/hid.usb0/subclass
        echo 64 > functions/hid.usb0/report_length
         # Set HID in/out desc
        echo -ne \\x05\\x81\\x09\\x82\\xa1\\x01\\x09\\x83\\x09\\x84\\x15\\x00\\x26\\xff\\x00\\x75\\x08\\x95\\x40\\x81\\x02\\x09\\x84\\x15\\x00\\x26\\xff\\x00\\x75\\x08\\x95\\x40\\x91\\x02\\xc0 > functions/hid.usb0/report_desc
        ln -s functions/hid.usb0 configs/c.1/
        # End functions

        ls /sys/class/udc > UDC
        ######USB HID Device end######
    else
        errlog "usb_gadget not found!"
        return 1
    fi
}

示例demo
usb设备节点为/dev/hidg0，以下为应用层USB收发示例；

c 复制代码

/* hid_gadget_test */

#include <pthread.h>
#include <string.h>
#include <stdio.h>
#include <ctype.h>
#include <fcntl.h>
#include <errno.h>
#include <stdio.h>
#include <stdlib.h>
#include <unistd.h>

#define BUF_LEN 512
struct options {
    const char    *opt;
    unsigned char val;
};

#define __is_print(ch)                ((unsigned int)((ch) - ' ') < 127u - ' ')
#define HEXDUMP_WIDTH                 16

void debug_hexdump(unsigned char *data, unsigned long size, unsigned char *headinfo)
{
    unsigned long i, j;
    unsigned long addr;

    printf("%s 0x%08X, size is %ld. The data is:\n", headinfo, addr,
           size);
    printf("Offset (h) 00 01 02 03 04 05 06 07 08 09 0A 0B 0C 0D 0E 0F\n");
    for (i = 0; i < size; i += HEXDUMP_WIDTH)
    {
        printf("[%08X] ", addr + i);
        /* dump hex */
        for (j = 0; j < HEXDUMP_WIDTH; j++)
        {
            if (i + j < size)
            {
                printf("%02X ", data[i + j]);
            }
            else
            {
                printf("   ");
            }
        }
        /* dump char for hex */
        for (j = 0; j < HEXDUMP_WIDTH; j++)
        {
            if (i + j < size)
            {
                printf("%c", __is_print(data[i + j]) ? data[i + j] : '.');
            }
        }
        printf("\n");
    }
    printf("\n");
}

int main(int argc, const char *argv[])
{
    const char *filename = NULL;
    int fd = 0;
    char buf[BUF_LEN];
    int cmd_len;
    char report[64] = {0};
    int to_send = 8;
    int hold = 0;
    fd_set rfds;
    int retval, i;

    if (argc < 2) {
        fprintf(stderr, "Usage: %s devname\n",
                argv[0]);
        return 1;
    }

    filename = argv[1];

    if ((fd = open(filename, O_RDWR|O_DSYNC, 0666)) == -1) {
        perror(filename);
        return 3;
    }

    while (1) {
        FD_ZERO(&rfds);
        FD_SET(fd, &rfds);

        retval = select(fd + 1, &rfds, NULL, NULL, NULL);
        if (retval == -1 && errno == EINTR)
            continue;
        if (retval < 0) {
            perror("select()");
            return 4;
        }

        if (FD_ISSET(fd, &rfds)) {
            cmd_len = read(fd, buf, BUF_LEN - 1);
#ifdef HEX_DEBUG
            debug_hexdump(buf, cmd_len, "recv report");
#endif
        }
    }

    close(fd);
    return 0;
}

附 wireshark USB抓包配置

安装wireshark 时同时安装USB抓包工具usbpcap后，打开wireshark有两个USB捕获接口

我们可以设置其中一个只抓取新接入的设备

USBPcap1 作用可指定抓取未接入的USB设备
USBPcap2 作用是抓取所有已接入的USB设备及新设备

linux模拟HID USB设备及wireshark USB抓包配置

1. 内核配置

2. 设备配置

附 wireshark USB抓包配置