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Date:   Tue, 31 Aug 2010 08:59:43 -0700
From:   David Daney <ddaney@caviumnetworks.com>
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To:     Ralf Baechle <ralf@linux-mips.org>
CC:     loody <miloody@gmail.com>,
        "Maciej W. Rozycki" <macro@linux-mips.org>,
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Subject: Re: some question about wmb in mips
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On 08/31/2010 07:33 AM, Ralf Baechle wrote:
> On Mon, Aug 30, 2010 at 09:58:27PM +0800, loody wrote:
>
>> after reading the DMA api document and check the source code.
>> I found mips seems not implement "dma map ops", but x86 has implemented it.
>> What are they used for and why mips don't implement it?
>
> This is useful for multiple sets of methods on more complicated systems.
> Right now we just don't need that.
>

That said, I am preparing a set of patches that converts MIPS to use 
struct dma_map_ops.  They turn out to be useful in systems where PCI 
devices need different treatment than on-chip devices, and when bounce 
buffers are needed form some devices, but not others.

David Daney