The file <cyg/hal/hal_ixp425.h> can be included from application and eCos package sources to provide definitions related to IXP4xx subsystems. These include register definitions for the PCI bus controller, SDRAM controller, DDR controller for IXP46x, expansion bus controller, I²C® controller for IXP46x, General purpose I/O (GPIO), interrupt controller, general-purpose timers and watchdog timer.
The file <cyg/hal/var_io.h> contains definitions used by the PCI support, as well as memory mapping details and macros to read and write the I/O space (including the PCI I/O space) at a variety of widths. If PCI IDE support has been enabled, it also provides the relevant support macros.