From: Arnd Bergmann <arnd@arndb.de>
To: Jiri Slaby <jirislaby@gmail.com>
Subject: Re: Do cpu-endian MMIO accessors exist?
Date: Wed, 22 Jul 2009 00:05:27 +0200
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Cc: Pekka Paalanen <pq@iki.fi>, linux-kernel@vger.kernel.org,
       Christoph Hellwig <hch@infradead.org>
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On Tuesday 21 July 2009, Jiri Slaby wrote:
> On 07/21/2009 11:15 PM, Arnd Bergmann wrote:
> > __raw_readl is not a replacement for real accessors like
> > ioread32 or in_be32, because it does not synchronize with the
> > instruction stream.
> 
> Aha, I see now. I guess it's a bug that ioread/write* on sh are not with
> barriers?

That depends on how that architecture defines its bus interface.
On many simple architectures, you do not need any synchronization
operations.

	Arnd <><
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