VULCAN Quickstart
Arcom Embedded Linux
Hardware configuration
PCI
The IXP425 has a 64MB PCI memory window, formed from four consecutive 16MB
windows, and located at the physical address 0x48000000. The PCI controller performs
byte-lane swapping from the big-endian processor side to the little-endian PCI side.
The IXP425 is not capable of producing byte or word (2 byte) PCI read cycles. Attempts
to do such a read result in an lword (4 byte) read. This is not an issue with any of the
on-board PCI devices but may be an issue for PC/104 boards.
PC/104 bus
The PC/104 bus on the VULCAN is accessed via the second socket of the PCI1520 PC
card controller on the PCI bus.
The Linux kernel configures the PCI1520 to map regions of PCI memory and I/O space
to ISA memory and I/O as follows:
PCI ISA
Memory
0x49000000 – 0x49FFFFFF
0x000000 – 0xFFFFFF
Memory (16-bit)
0x4a000000 – 0x4AFFFFFF
0x000000 – 0xFFFFFF
I/O
1
0x0000 – 0x0FFF
0x0000 – 0x0FFF
I/O (16-bit)
0x1000 – 0x1FFF
0x0000 – 0x0FFF
1
0xF000 - 0xFFFF is reserved for CF+ cards.
The PC card controller does not handle the IOIS16# or MEMIS16# PC/104 bus signal
and accesses are split into 8-bit accesses by default. The 16-bit memory and I/O
windows listed above can be used for 16-bit accesses.
PCI I/O cannot be mapped to the processor's address space, so PCI I/O must be done
via the IXP425 PCI controller's registers. The standard Linux kernel I/O functions (inb,
outb, inw, outw, etc.) are provided for this purpose.
© 2005 Arcom Issue D
20
