Re: How do I access ioports from userspace?

Peter Chubb
2003-09-28T23:08:08Z

>>>>> "Jes" == Jes Sorensen <jes@trained-monkey.org> writes:

>>>>> "Ben" == Benjamin Herrenschmidt <benh@kernel.crashing.org> writes:
Ben> On Fri, 2003-09-26 at 09:34, Frank v Waveren wrote:
>>> in[bwl]/out[bwl] are available on a lot more than just x86. Mind
>>> you, the mechanisms are subtly different. Then again, if you're
>>> using direct hardware access you're not going for portability
>>> anyway.

Ben> Are they from userland ? I doubt it...

Jes> Actually yes on some architectures, ia64 emulates it the ia32
Jes> API. That said, it's certainly not something one should be
Jes> encouraged to do, using MMIO is a far better approach.

They're available at least in i386, alpha, ia64.
However they allow access only to the first 64k of IO address space.
So you may not be able to access you device if it's in the wrong PCI
slot...

--
Dr Peter Chubb http://www.gelato.unsw.edu.au peterc AT gelato.unsw.edu.au
You are lost in a maze of BitKeeper repositories, all slightly different.