From: Benjamin Herrenschmidt <benh@kernel.crashing.org>
To: "David S. Miller" <davem@redhat.com>
Cc: Olaf Hering <olh@suse.de>,
Linux Kernel list <linux-kernel@vger.kernel.org>
Subject: Re: consistent_sync_for_cpu() and friends on ppc32
Date: Tue, 16 Mar 2004 08:59:16 +1100 [thread overview]
Message-ID: <1079387955.1966.177.camel@gaston> (raw)
In-Reply-To: <20040315123647.4ce943b7.davem@redhat.com>
> Ben, can you work this out? I can make it compile by just making the
> _for_cpu and _for_device routines behave identically to what the
> consisten_sync{,_page}() stuff does now. But I'd much rather a ppc32
> person implement it correctly and optimally.
>
> In short, the _for_device routines should make sure cacheable data in
> the cpu is fully visible to the DMA device, and _for_cpu should make
> sure all device DMA is visible to the processor.
Yup, it depends for what CPU the kernel is compiled, normal desktop
CPUs are completely coherent, so this will be a no-op, but 4xx/8xx
embedded CPUs will need something better. I'll have a look today
Ben.
next prev parent reply other threads:[~2004-03-15 22:07 UTC|newest]
Thread overview: 8+ messages / expand[flat|nested] mbox.gz Atom feed top
2004-03-15 20:16 consistent_sync_for_cpu() and friends on ppc32 Olaf Hering
2004-03-15 20:36 ` David S. Miller
2004-03-15 21:59 ` Benjamin Herrenschmidt [this message]
2004-03-16 0:23 ` Benjamin Herrenschmidt
2004-03-16 0:49 ` David S. Miller
2004-03-16 1:36 ` Benjamin Herrenschmidt
2004-03-16 18:46 ` David S. Miller
2004-03-16 21:54 ` Benjamin Herrenschmidt
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