Re: [PATCH] Clarify pci_iomap() usage for MMIO-only devices
From: Linus Torvalds
Date: Tue Sep 18 2007 - 15:04:25 EST
On Tue, 18 Sep 2007, Luis R. Rodriguez wrote:
>
> Alright, here is the same patch inline with s/recommended/required/ language:
Well, the thing is, I'm not at all sure that I agree with this.
If you use ioport_map/unmap, then you really *should* access them with the
proper iomem accessors (ioread/iowrite). The fact that it may happen to
work (when using the default lib/iomap.c implementation, at least) on
some architectures and with the current implementation still doesn't mean
that you should necessarily use readb/writeb.
After all, you cannot use "inb/outb" on it, even if would happen to be an
IO address.
So what is this usage that wants to use the bogus accessor? Why not fix
that instead of adding documentation for something that is very arguably
something we want to *avoid* having people do!
Linus
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