Re: [PATCH] asm-generic: add dma-mapping-linear.h

FUJITA Tomonori
2009-06-01T09:17:09Z

On Mon, 1 Jun 2009 09:29:43 +0100
Russell King <rmk+lkml@arm.linux.org.uk> wrote:

> On Mon, Jun 01, 2009 at 05:08:09PM +0900, FUJITA Tomonori wrote:
> > This adds a version of the dma-mapping API to asm-generic that can be
> > used by most architectures that only need a linear mapping.
>
> It depends what is meant by "linear mapping".
>
> If that's just a way of saying "all that needs to be done for the
> DMA streaming APIs is to flush the cache" then the vast majority of
> ARMs fall into that category.

I guess that his definition is 'no dynamic remapping'.

> The DMA bounce code is a broken design concept that really needs to
> be put to death.

You are talking about arch/arm/common/dmabounce.c? If so, it sounds
more interesting (to me at least). It's kinda swiotlb per device,
right? What you want to do for arch/arm/common/dmabounce.c?