May I ask a question about how to configure USB for the kernel?

I would like to ask a question about Kernel configuration USB-general Linux technology-Linux programming and kernel information. The following is a detailed description. My Development Board is Omap5912 (TI arm9-+ DSP), and the embedded system uses the free MontaVista linux. There is a serial port and a USB port on the board. During kernel compilation, the USB port is compiled into the kernel (some of the main USB configuration items are selected, which is different here ), you can see the following items during the U-Boot startup process:
Usb. c: registered new driver usbdevfs;
Usb. c: registered new driver hub;
Usb. c: registered new driver serial;
USB Serial. c: USB Serial support registered for Generic;
USB Serial. c: USB Serial support Driver core v1.4;
After the system is started, run the dmesg command to view the driver information again.
In the root file system, we can see that there is an empty/usb directory in the/dev directory, and there is no
/Dev/sda1 directory (when using the usb flash drive function of the PC, directly tap "mount-t vfat/dev/sda1/mnt/usb ")
The following is the Problem description:

1. Connect a USB flash drive to the USB port of the Development Board. Is there no enumeration process? Or didn't the Board provide power to the U port? Or do I need to set the system to power or the connected device to power itself during kernel compilation?

2. According to the above mount command, press mount-t vfat/dev/usb/mnt/usb. The result is as follows:
Mount: Mounting/dev/usb on/mnt failed: Block device required

3. when you tap mount-t usbdevfs none/proc/bus/usb, it is found that the/devices and/drivers directories are missing in the original/usb directory, the/drivers directory contains three files: usbdevfs, hub, and serial, while the/devices directory is empty.

I would like to ask a brother with similar experience. How can I explain the above question? Is the USB driver not mounted? How should we test and verify the USB FUNCTION OF THE DEVELOPMENT BOARD step by step to ensure the correctness of the USB function.

In addition, the default make menuconfig configuration of the system kernel compiles USB in the module mode. You can see some information about usb under/kernel/drivers *. o Driver file, but the system's busybox command does not provide the insmode command. What is the use of these drivers?