u-boot/doc/README.generic_usb_ohci

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Notes on the the generic USB-OHCI driver
========================================
This driver (drivers/usb_ohci.[ch]) is the result of the merge of
various existing OHCI drivers that were basically identical beside
cpu/board dependant initalization. This initalization has been moved
into cpu/board directories and are called via the hooks below.
Configuration options
----------------------
CONFIG_USB_OHCI_NEW: enable the new OHCI driver
CFG_USB_OHCI_BOARD_INIT: call the board dependant hooks:
- extern int usb_board_init(void);
- extern int usb_board_stop(void);
- extern int usb_cpu_init_fail(void);
CFG_USB_OHCI_CPU_INIT: call the cpu dependant hooks:
- extern int usb_cpu_init(void);
- extern int usb_cpu_stop(void);
- extern int usb_cpu_init_fail(void);
CFG_USB_OHCI_REGS_BASE: defines the base address of the OHCI registers
CFG_USB_OHCI_SLOT_NAME: slot name
CFG_USB_OHCI_MAX_ROOT_PORTS: maximal number of ports of the root hub.
Endianness issues
------------------
The LITTLEENDIAN #define determines if the 'swap_16' and 'swap_32'
macros do byte swapping or not. But some cpus OHCI-controllers such as
ppc4xx and mpc5xxx operate in little endian mode, so some extra ifdefs
were necessary to make this work.