Yosemite/440EP why are readl()/ioread32() setup toreadlittle-endian?

Jenkins, Clive Clive.Jenkins at xerox.com
Thu Feb 2 21:28:05 EST 2006


> > On Thu, Feb 02, 2006 at 09:35:56AM -0000, Jenkins, Clive wrote:
> > A driver for some device that could be connected to (or plugged
into)
> > a variety of different platforms of different architecture.
> > A driver for a core that could be implemented within an FPGA on
> > multiple platforms.

> Well, this is all nice but I was wondering about _real_ examples.
> When you are talking about "connecting" or "plugging" you have to keep

> in mind actual bus interconnect. So far AFAIK PCI (and derivatives) 
> are the only cross-arch bus.

Yes, I do realise that in most cases PCI is used for cross-arch
interconnect. But without knowing about all the relevant hardware in the
world, I couldn't say that there are no other cross-arch buses.
And what about direct connection to the local bus of the processor chip?
 
> So basically, you have no _real_ life examples, so I'm wondering why 
> people need this "arch-independent" non-PCI I/O accessors for 
> something which doesn't exist.

I could draft a design of such an example, and I could realise that
design
by building it. But I don't want to spend the time and money doing it.
Neither do I want to spend time researching _real_ examples.
It is much easier to allow for obvious possibilities that _could_ exist
and probably will exist if they don't already, than searching the world.

Why be PCI-centric now, when we have experienced no end of problems
because Linux was x86-centric in the past?

> I think the reason why Linux doesn't have this stuff follows from the 
> previous paragraph.

Clive



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