Re: [Ocf-linux-users] OCF Talitos driver - DMA alignment

[Kim P. <kim...@fr...>]

On Tue, 11 May 2010 13:22:38 +0300
avital sela <avi...@gm...> wrote:

> Hi Kim,

Hi Avital,

> I'm working on an ocf driver for a custom made hw that does AES and SHA, and
> uses DMA.
> I've noticed that in your talitos driver you also used DMA but you never
> checked for alignment, whereas in David's Safenet code he did check for
> alignments.
> My questions are:
> 1. are you using a 1-byte aligned DMA, therefore you don't need alignment?

correct, talitos drives h/w that doesn't have alignment restrictions.

> 2. or alternatively, is there some way to guarantee that buffers are 32bit
> aligned beforehand?

In OCF-linux, both safe and hifn drivers look like they copy data to
ensure alignment.

In the upstream kernel's crypto API, it looks like a crypto
drivers' .cra_alignmask setting is used for this purpose.

[cc:ing ocf list in case there's something I'm missing.]

Kim