Subject: Re: powerpc: DMA coherent allocations broken for CONFIG_NOT_COHERENT_CACHE

From: Benjamin Herrenschmidt <[email-masked]>
Date: Thu, 28 May 2009 13:52:29 +1000

On Wed, 2009-05-27 at 23:34 -0400, Sean MacLennan wrote:
> On Mon, 25 May 2009 14:33:43 +1000

  ../..

You can just make it a platform device I suppose. In the meantime...

> Maybe set ISA_DMA_THRESHOLD somewhere? Some platforms seem to set it:
> 
> ./platforms/52xx/efika.c:       ISA_DMA_THRESHOLD = ~0L;
> ./platforms/amigaone/setup.c:           ISA_DMA_THRESHOLD = 0x00ffffff;
> ./platforms/chrp/setup.c:       ISA_DMA_THRESHOLD = ~0L;
> ./platforms/powermac/setup.c:   ISA_DMA_THRESHOLD = ~0L;
> 
> So if anybody knows another way around this? The driver is basically
> allocating a scatter gather list that is passed to a DMA engine in the
> FPGA.
> 
> This isn't a showstopper.... we are not planning to move to 2.6.30 in
> the near future.

Can't you set ISA_DMA_THRESHOLD = ~0L from your warp.c platform file ?

Cheers,
Ben.