Re: drivers/usb/musb/musb_io.h

[Russell King <rmk-lFZ/pmaqli7XmaaqVzeoHQ@public.gmane.org>]

On Fri, Aug 15, 2008 at 02:11:31AM -0700, Andrew Morton wrote:
> On Fri, 15 Aug 2008 11:52:48 +0300 Felipe Balbi <me-uiRdBs8odbtmTBlB0Cgj/Q@public.gmane.org> wrote:
> 
> > Wonder if it's possible to have the above patch applied so I can get rid
> > of those stubs in musb_io.h
> 
> Someone would need to take care of it and document it and repair all
> those driver which broke because they went and created private copies.
> 
> I could do some of that but I'm stuck at step #1.  What the heck _are_
> these things?  Why do they exist?  What are their semantics?
> 
> The arm implementation says
> 
>  * Generic IO read/write.  These perform native-endian accesses.  Note
>  * that some architectures will want to re-define __raw_{read,write}w.
> 
> which is somewhat clear as mud.  I'd guess that these are the MMIO
> partners to insl and friends?

Yes.

> And then it has
> 
> extern void __raw_writesb(void __iomem *addr, const void *data, int bytelen);
> extern void __raw_writesw(void __iomem *addr, const void *data, int wordlen);
> extern void __raw_writesl(void __iomem *addr, const void *data, int longlen);
> 
> which is a bit odd.

Shrug.  Everything is not a PC.  I don't see anything odd about the above.

We basically implement a standard set of IO macros (the __raw_*) stuff
which is used to implement the standard set of IO support (inl, insl)
and provide a set of extensions for our platforms (readsl to complement
insl - named precisely the same way because that's what they are) because
the generic stuff doesn't cover all our needs.

> I assume that "bytelen" should have been "bytecount" or similar.

bytelen and bytecount mean the same thing to me.

-- 
Russell King
 Linux kernel    2.6 ARM Linux   - http://www.arm.linux.org.uk/
 maintainer of:
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