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

[Michal Simek <monstr@monstr.eu>]

On 12/08/2012 11:57 AM, Geert Uytterhoeven wrote:
> On Fri, Dec 7, 2012 at 10:16 PM, Alan Cox <alan@lxorguk.ukuu.org.uk> 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