On Sun, Feb 05, 2023 at 07:33:46PM +0100, Olliver Schinagl wrote: > > I always thought that SWAP_IO_SPACE is needed for big endian, but > > looking at arch/mips/Kconfig I see a lot of SWAP_IO_SPACE for pure > > little endian machines. I need to dig deeper to understand why. > Thank you! and the reason why this works is simple, CONFIG_SWAP_IO_SPACE is a nop for little endian. > > such a change would defeat the generic part of GENERIC_MIPS_KERNEL, > > because it will then only work on REALTEC_SOC and nothing else. > Ignoring the potential incorrect detail here, obviously I would prefer to > use the GENERIC_MIPS_KERNEL, but having to copy the whole config just to > leave out that one option also is kinda meh. So i'm hoping we can find a > solution of course :) what SOC is this exactly ? Do you have a programmers manual for it, which contains details about the PCI bridge ? Most of the PCI bridges used for MIPS contain a bit to select the endianess of the access to PCI spaces. If there is such a config just changing the current setting, should solve your problem. If this isn't possible you could use something similair to the INGENIC approach, which could use a generic kernel but also an customized kernel. And in such a customized kernel it should be possible to remove SWAP_IO_SPACE. Thomas. -- Crap can work. Given enough thrust pigs will fly, but it's not necessarily a good idea. [ RFC1925, 2.3 ]
