使用USB gadget驱动测试USB芯片驱动功能

1. 在内核中使能Mass Storage Gadget ，如下图，配置路径是Linux/arm64 4.14.0 Kernel Configuration
   → Device Drivers → USB support → USB Gadget Support ->Mass Storage Gadget
   
2. 使能Pseudo文件系统，如图
   
3. 配置Device Tree

&dwc3_0 {
	status = "okay";
	dr_mode = "peripheral";
	snps,usb3_lpm_capable;
	phy-names = "usb3-phy";
	phys = <&lane2 4 0 2 26000000>;
	maximum-speed = "super-speed";
};

4. dd if=/dev/zero of=/tmp/test.img bs=1M count=256
5. insmod g_mass_storage.ko file=/tmp/test.img removable=1
   运行结果：