summaryrefslogtreecommitdiff
path: root/doc/README.generic_usb_ohci
diff options
context:
space:
mode:
Diffstat (limited to 'doc/README.generic_usb_ohci')
-rw-r--r--doc/README.generic_usb_ohci57
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 0000000..494dd1f
--- /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