Re: [PATCH 7/7] OF: set dma_mask for ARM

Grant,

On 11/16/2010 11:24 PM, Grant Likely wrote:

On Tue, Nov 16, 2010 at 02:33:55PM -0600, Rob Herring wrote:

quoted

From: Rob Herring<rob.herring-bsGFqQB8/DxBDgjK7y7TUQ@public.gmane.org>

Various drivers require dma_mask to be valid, so it needs to be setup
when doing OF probing on ARM.

Signed-off-by: Rob Herring<rob.herring-bsGFqQB8/DxBDgjK7y7TUQ@public.gmane.org>

I'll let patches 6&  7 lay fallow for the moment.  I'm not hugely fond
of the powerpc approach (which microblaze copies), but I haven't had a
chance to look for a better solution.

Looking at this some more, there's a couple of options I see.

Other buses (ISA, PCI, EISA) have a dma_mask in their struct. So perhaps 
platform_device should just have a dma_mask field.

There are several examples of setting dma_mask = &coherent_dma_mask. I'm 
not sure if this is considered correct. At least on ARM, I don't think 
these would need to be different.

Another option would be using bus notifiers to set the dma_mask like 
platform_data. But that doesn't seem like a good long term solution.

Rob