EHCI,OHCI,UHCI Concepts and differences

Basic concepts of UHCI EHCI OHCI

UHCI (Universal Host Controller Interface): Hardware interface of the USB 1.1 Master controller (host controller) used by Intel on its own chipset
The EHCI (Enhanced host Controller Interface) Enhanced Host Controller Interface specification describes a register-level interface for a Universal serial Bus (USB) version 2.0 host controller. The specification includes a description of the hardware/software interface between the system software and the host controller hardware. The purpose of this specification is to develop hardware component design, system integrators, and device drivers (software).
OHCI (Open Host controller Inferface): A host Controller interface standard that is not just for USB. Mainly follow the CSR (Configuration Space register) standard. is the standard that other vendors follow when designing USB host controller, such as Via, NEC, Ali, including Nvidia, and so on.
EHCI is a hardware design that meets the requirements for USB host controller (high speed) in USB 2.0 specification.

Differences between UHCI and OHCI
    hardware, USB host controller must be available in addition to the peripherals themselves. In general, a computer has a USB host Controller on it, it can control a lot of devices, such as U disk, USB keyboard, USB mouse. All peripherals submit their requests to the USB host controller. Then let the USB host controller Unified Dispatch.
   now General USB bridge modules are available in two types, UHCI and OHCI. When deciding which bridge module to insert, you can view the/proc/pci file to determine ... In general, the UHCI type of the bridge its plug-in module is UHCI or USB-UHCI (determined by the kernel version), and for OHCI type of bridge its plug-in module is OHCI or USB-OHCI. The
       "EHCI" Driver design is supported by a chip that implements the new high-speed USB 2.0 protocol. The "OHCI" driver is used to support USB chips on non-PC systems (and on PC motherboards with SiS and ali  chipsets). The "UHCI" driver is used to support USB implementations on most other pc  motherboards, including Intel and Via. Simply select the type of USB support you want to enable. HCI driver.