From: Arnd Bergmann <arnd@arndb.de>
To: Jonas Bonn <jonas@southpole.se>
Subject: Re: [PATCH 07/19] OpenRISC: DMA
Date: Sun, 19 Jun 2011 21:02:30 +0200
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On Sunday 19 June 2011 13:43:33 Jonas Bonn wrote:
> 
> Simple DMA implementation.  There's some work to do here, but
> this allows for allocation of coherent memory (simply uncached) for DMA
> operations.
> 
> Signed-off-by: Jonas Bonn <jonas@southpole.se>
> ---
>  arch/openrisc/include/asm/dma-mapping.h |  129 ++++++++++++++++++++++++++
>  arch/openrisc/kernel/dma.c              |  152 +++++++++++++++++++++++++++++++
>  2 files changed, 281 insertions(+), 0 deletions(-)
>  create mode 100644 arch/openrisc/include/asm/dma-mapping.h
>  create mode 100644 arch/openrisc/kernel/dma.c

If you don't have an IOMMU or the need for swiotlb, you can probably eliminate
the use of dma_map_ops and just provide the simple implementation.

For the operations that you have not implemented properly, I would leave
a forward-declaration but remove the implementation that causes a runtime
error, so you turn that into a link time error.

	Arnd
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