Re: [PATCH 6/6] atmel_serial: Add DMA support

From: Marc Pignat
Date: Wed Jan 23 2008 - 08:53:00 EST


On Wednesday 23 January 2008, Haavard Skinnemoen wrote:
> On Wed, 23 Jan 2008 14:18:38 +0100
...
> GFP_DMA doesn't have anything to do with alignment, AFAIK.
I don't even know if it does something for at91 or avr32, but there is a flag
for dma memory, so we should use it.

...
> No, please don't. If you're thinking of dma_alloc_coherent(), it means
> that the cache will be bypassed when accessing the buffer (slower), and
> that the size will be rounded up to the next multiple of the page size
> (larger). If the sole purpose of doing that is to get properly aligned
> buffers, we might as well use the page allocator directly.
ok.

Marc


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