On Fri, Dec 7, 2012 at 10:16 PM, Alan Cox <alan@xxxxxxxxxxxxxxxxxxx> wrote: >> Because I need to use IO functions which will behave >> on arm as little endian and on powerpc as big endian >> and on microblaze depends on endian setting. >> I haven't found any IO function which I could use by 3 architectures >> without using preprocessor macros or runtime detection > > Its a rather weird mix. We can do "always big" and "always little" > >> 1. Using helper function + preprocessor macros >> (using static inline function also possible) > > Then someone comes along and sticks a daughterboard into the system with > the same device the other way around and there are years > >> 2. Using function pointers > > Probably smarter. 8250.c works this way and it has to handle some > extremely bizarre mappings. > >> b) Runtime initialization - here is the question if there is >> any standard function which I could use. > > Set the pointers up and pass them as data with your platform device, that > way the function definitions are buried in your platform code where they > depend. Or embed a struct io_ops * in struct device, to be set up by the bus driver? Wasn't David Hinds working on something like this in the context of PCMCIA a few decades ago? Gr{oetje,eeting}s, Geert -- Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- geert@xxxxxxxxxxxxxx In personal conversations with technical people, I call myself a hacker. But when I'm talking to journalists I just say "programmer" or something like that. -- Linus Torvalds -- To unsubscribe from this list: send the line "unsubscribe linux-arch" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html