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SubjectRe: __LITTLE_ENDIAN vs. __LITTLE_ENDIAN_BITFIELD
Lennart Sorensen wrote:

>> You're talking about byte endian. I'm talking about bit endian -- the
>> order of bits within a byte. Software cannot know what the bit endian is,
>> but external devices that have memory-mapped registers can know.
>
> The guy wiring up the hardware should connect the wires correctly.

I'm sure they're correct, my problem is that how can my driver know what they are?

> Doesn't the bus usually have some definition of bit order which the
> device would have to adhere to? After all there must be address lines
> somewhere.

I was hoping that there would be some compile-time constant I could check that
would give me this information.

> Does this perhaps offer anything useful?
> http://www.linuxjournal.com/article/6788

Yeah, I read that article some time ago when trying to diagnose the problem I
was seeing. It does explain the point I'm trying to make. We have a device
that's used on two product lines: one ARM-based, and one PowerPC. The ARM is
little-endian, and the PowerPC is big-endian. The device can support
little-endian or big-endian data, as long as the bit-order matches the byte-order.

For now, I'm going to have to assume that they do match.

--
Timur Tabi
Linux Kernel Developer @ Freescale
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