On 11/14/2013 03:31 AM, Graham Whaley wrote: [...]
Hi David, out of interest, do you know if there are any commercially (ideally easily and cheaply ;-) available boards out there that can run Octeon little endian?
I don't know...
afaik things like the CN5020 based boards like the Erlite-3 and CAM-0100 only do big, and afaik there is no (documented) way to jumper them differently.
On OCTEON, the endianess is under software control, it is *not* a hardware strapping option. With a suitable bootloader, we still start the system in big endian mode, but if a little-endian ELF image is loaded, we note the endianness, and switch to little endian mode as control is passed to the program entry point.
It has only really been validated on OCTEON II and OCTEON III devices (cn6xxx and cn7xxx). Certianly the CPU cores on the cn5020 are capable of little endian operation. The I/O blocks on the other hand have not been validated for little endian operation on that part.
It is known that the bootbus (where the NOR boot flash is connected) has problems in little endian mode on cn5020, so you probably wouldn't be able to use that from Linux. Also the USB controller on cn5020 has not been adapted and validated for little endian use, so there would be work there.
My presumption is that the Cavium Octeon devboards from Cavium themselves (available I believe, but not too cheap) can do both?
As I said above, it is under software control, so any board should be able to do it (given the proper software).
David Daney