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Diffstat (limited to 'doc/README.generic_usb_ohci')
| -rw-r--r-- | doc/README.generic_usb_ohci | 57 |
1 files changed, 57 insertions, 0 deletions
diff --git a/doc/README.generic_usb_ohci b/doc/README.generic_usb_ohci new file mode 100644 index 000000000..494dd1f5d --- /dev/null +++ b/doc/README.generic_usb_ohci @@ -0,0 +1,57 @@ +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 USB bus operates in little endian, but unfortunately there are +OHCI controllers that operate in big endian such as ppc4xx and +mpc5xxx. For these the config option + + CFG_OHCI_BE_CONTROLLER + +needs to be defined. + + +PCI Controllers +---------------- + +You'll need to define + + CONFIG_PCI_OHCI + +PCI Controllers need to do byte swapping on register accesses, so they +should to define: + + CFG_OHCI_SWAP_REG_ACCESS |