Re: More DMA API junk

[James Bottomley <James.Bottomley@steeleye.com>]

On Mon, 2004-03-15 at 19:53, Benjamin Herrenschmidt wrote:
>  - dma_is_consistent(dma_addr_t address) : Did somebody actually expect
> anything useful out of this function ? AFAIK, it makes no sense. There
> is simply no way an arch like ppc that use per-page cache-inhibit
> mappings to do consistent memory will be able to tell you if a given
> _DMA_ address is consistent... that makes no sense.

>  - dma_cache_sync(): What is that function supposed to do ? It's a
> duplicate of the other sync() functions and David didn't even bother
> turning it into _for_device/for_cpu... which is fine since it doesn't
> even takes a struct device argument.

They are both used.  Look at section II of DMA-API.txt.cd ..

They have to do with incoherent platforms which I assume you don't have,
but just leave them alone for those of use who are so burdened.

Actually, I was planning to update dma_cache_sync to take a device and
to conform to the new style (except I was thinking of an ownership flag
rather than introducing two more APIs).  The lack of device to
dma_cache_sync is probably irrelevant since they only apply to older
arch's which don't have bus caches.

James