USB OTG Controller Register Guide

= USB OTG = All Allwinner A-series SoCs come with one USB OTG controller. The controller has been identified as a Mentor Graphics Inventra HDRC (High-speed Dual Role Controller), which is supported by the "musb" driver.

The A20 manual lists the following features
 * Complies with USB 2.0 specification
 * Supports high-speed, full-speed, and low-speed in host mode
 * Supports high-speed and full-speed in device mode
 * 64 byte endpoint 0 for control transfer
 * Supports up to 5 user configurable endpoints for bulk, isochronous, control, and interrupt bi-directional transfers

The USB OTG controller is connected to a port controller. Only the data pins are exported from the SoC. The port controller is also used to control or tune the USB PHYs for the other USB host controllers.

Info

 * USB OTG Controller base address: 0x01c13000
 * USB Port Controller base address: 0x01c13400

ISCR
Default value: 0x40000000

Offset: 0x0

PHY_CTRL
Default value: 0x0000

Offset: 0x0