Re: Using IO functions across ARM, PPC and Microblaze architectures

[Michal Simek]

On 12/08/2012 11:57 AM, Geert Uytterhoeven wrote:
> 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?


Do you have any link on that?

Thanks,
Michal



--
Michal Simek, Ing. (M.Eng)
w: www.monstr.eu p: +42-0-721842854
Maintainer of Linux kernel 2.6 Microblaze Linux - http://www.monstr.eu/fdt/
Microblaze U-BOOT custodian
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/