CPU Cache and busdma usage in USB

[Hans Petter Selasky]

On Wednesday 08 July 2009 10:58:17 Rafal Jaworowski wrote:
> On 2009-07-07, at 18:46, Hans Petter Selasky wrote:
> >> I had Checked USB behaviour on PowerPC without hardware cache
> >> coherency.
> >> The problem also exists here and patch helps.
> >
> > In my source code view the busdma sync function is empty for power-
> > pc. Your
> > patch should have no effect at all for sync operations?
>
> This was about the PPC4xx PowerPC port, not committed to the tree yet.
> Unlike most PowerPC this system has a de-coherent DMA and therefore
> its busdma sync is non empty, but needs to enforce coherency by
> software.
>
> The point is this is another platform on which USB stack (usb_pc_cpu_*
> functions) shows similar issues as reported for ARM and MIPS.

And what about my patch suggestion in my previous e-mail having the same 
subject. Does it work?

Regarding my testing on the AT91RM9200 I was short of time yesterday and will 
try to get it done today.

--HPS