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From: Grant Grundler <grundler@parisc-linux.org>
To: Matthew Wilcox <matthew@wil.cx>
Cc: parisc-linux@parisc-linux.org
Subject: Re: [parisc-linux] readb/__raw_readb/gsc_readb and ioremap
Date: Sat, 30 Oct 2004 22:37:16 -0600	[thread overview]
Message-ID: <20041031043716.GD5050@colo.lackof.org> (raw)
In-Reply-To: <20041031033950.GN8958@parcelfarce.linux.theplanet.co.uk>

On Sun, Oct 31, 2004 at 03:39:50AM +0000, Matthew Wilcox wrote:
> __raw_read/writeX:
>  - Don't byteswap
>  - Should be used on ioremap'ed address
> read/writeX:
>  - Byteswap
>  - Should be used on ioremap'ed address

Willy confirmed there is another subtle difference between the
two sets of functions:
	__raw_read/writeX relax PCI ordering requirements.
	read/writeX enforce PCI Ordering requirements.

Willy correctly ignored this topic since parisc machines are strongly
ordered for IO as well (so far at least).
But I didn't want folks to think byte swapping was the only difference.

Be VERY careful of using __raw_XXX forms outside of parisc specific code.

grant
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      reply	other threads:[~2004-10-31  4:37 UTC|newest]

Thread overview: 2+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2004-10-31  3:39 [parisc-linux] readb/__raw_readb/gsc_readb and ioremap Matthew Wilcox
2004-10-31  4:37 ` Grant Grundler [this message]

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