要内核支持USB设备，首先要在内核中使能USB相关选项，然后要在设备树中添加USB设备，然后就可以使用板卡上的USB接口读取优盘或者是UVC摄像头了。

• 配置内核

由于USB相关内核配置较多，因此不使用menuconfig在图形界面中逐个配置，直接在kernel config文件中改动
在project-spec/meta-user/recipes-kernel/linux/linux-xlnx/*.cfg中添加

CONFIG_MEDIA_USB_SUPPORT=y
CONFIG_USB_VIDEO_CLASS=y
CONFIG_USB_VIDEO_CLASS_INPUT_EVDEV=y
CONFIG_USB_GSPCA=m
CONFIG_V4L_PLATFORM_DRIVERS=y
CONFIG_VIDEO_ADV7604=y
CONFIG_USB_HID=y
CONFIG_USB_OHCI_LITTLE_ENDIAN=y
CONFIG_USB_SUPPORT=y
CONFIG_USB_COMMON=y
CONFIG_USB_ARCH_HAS_HCD=y
CONFIG_USB=y
CONFIG_USB_ANNOUNCE_NEW_DEVICES=y
CONFIG_USB_DEFAULT_PERSIST=y
CONFIG_USB_EHCI_HCD=y
CONFIG_USB_EHCI_ROOT_HUB_TT=y
CONFIG_USB_EHCI_PCI=y
CONFIG_USB_EHCI_HCD_PLATFORM=y
CONFIG_USB_ACM=m
CONFIG_USB_PRINTER=m
CONFIG_USB_WDM=m
CONFIG_USB_TMC=m
CONFIG_USB_STORAGE=y
CONFIG_USB_CHIPIDEA=y
CONFIG_USB_CHIPIDEA_OF=y
CONFIG_USB_CHIPIDEA_PCI=y
CONFIG_USB_CHIPIDEA_HOST=y
CONFIG_USB_PHY=y
CONFIG_NOP_USB_XCEIV=y
CONFIG_AM335X_CONTROL_USB=y
CONFIG_AM335X_PHY_USB=y
CONFIG_USB_GPIO_VBUS=y
CONFIG_USB_ULPI=y
CONFIG_USB_ULPI_VIEWPORT=y

如果没有project-spec/meta-user/recipes-kernel/linux/linux-xlnx/*.cfg文件，可以使用

$ petalinux-config -c kernel

随便修改一个选项就可以生成kernel config文件。

• 配置设备树

project-spec/meta-user/recipes-bsp/device-tree/files/system-user.dtsi中添加

/{
 usb_phy0: usb_phy@0 {
  compatible = "ulpi-phy";
  #phy-cells = <0>;
  reg = <0xe0002000 0x1000>;
  view-port = <0x0170>;
  drv-vbus;
 };
};
&usb0 {
 dr_mode = "host";
 usb-phy = <&usb_phy0>;
};

• 编译工程

$ petalinux-build