[flashrom] [PATCH] Add support for SPARC (maybe).

[Carl-Daniel Hailfinger]

On 08.02.2015 22:16, Stefan Tauner wrote:
> On Sun, 08 Feb 2015 17:55:10 +0100
> Carl-Daniel Hailfinger <c-d.hailfinger.devel.2006 at gmx.net> wrote:
>
>> On 07.02.2015 19:49, Stefan Tauner wrote:
>>> Was implemented by SPARC newbies, does (cross-)compile but is not run-tested.
>>>
>>> Signed-off-by: Stefan Tauner <stefan.tauner at alumni.tuwien.ac.at>
>> Thanks!
>>
>> Quoting wikipedia:
>>> The endianness of the 32-bit SPARC V8 architecture is purely
>>> big-endian. The 64-bit SPARC V9 architecture uses big-endian
>>> instructions, but can access data in either big-endian or
>>> little-endian byte order, chosen either at the application instruction
>>> (load/store) level or at the memory page level (via an MMU setting).
>>> The latter is often used for accessing data from inherently
>>> little-endian devices, such as those on PCI buses.
>> If that is true, we are totally screwed. How can we even begin to
>> influence the instructions emitted by the compiler? And if the compiler
>> emits bigendian instructions by default, can that be overridden via MMU
>> setting? If yes, does Linux use the endianness manipulation via MMU for
>> PCI devices, in which case we'd have to treat the architecture as
>> littleendian from a flashrom POV?
>>
>> This is a nightmare.
>>
> Only if you make it one. :)
> Maybe this allows you to sleep better:
> https://gcc.gnu.org/ml/gcc-patches/2011-10/msg02240.html

Excellent, this means GCC won't try to screw us.


> I am not sure if that "MMU settings" in wikipedia is referring to the
> address space identifiers (ASIs), but it definitely screams [citation
> needed]. 
> In general the whole thing looks like a rather exotic if not esoteric
> feature added to make porting Windows easier... in any case I am very
> confident that it will not be encountered on real machines/OSes.

Yay!


> So... the only question is if you agree and we commit this before
> tagging 0.9.8-rc1 or not. I don't care too much about SPARC support,
> but I *do* care about getting the release out. Please respond in a
> timely manner.

With all this info and your excellent explanations on IRC, I want to say
Thank You!
Acked-by: Carl-Daniel Hailfinger <c-d.hailfinger.devel.2006 at gmx.net>

Regards,
Carl-Daniel