Re: omap3isp device tree support

[Florian Vaussard <florian.vaussard@epfl.ch>]

Hi,

On 01/09/2014 09:49 PM, Laurent Pinchart wrote:
> Hi Florian,
> 
> On Thursday 09 January 2014 21:26:58 Florian Vaussard wrote:
>> On 01/07/2014 05:59 PM, Laurent Pinchart wrote:
>>> On Friday 03 January 2014 12:30:33 Enrico wrote:
>>>> On Wed, Dec 18, 2013 at 11:09 AM, Enrico wrote:
>>>>> On Tue, Dec 17, 2013 at 2:11 PM, Florian Vaussard wrote:
>>>>>> So I converted the iommu to DT (patches just sent),
>>>
>>> Florian, I've used your patches as a base for OMAP3 ISP DT work and they
>>> seem pretty good (although patch 1/7 will need to be reworked, but that's
>>> not a blocker). I've just had to fix a problem with the OMAP3 IOMMU,
>>> please see
>>>
>>> http://git.linuxtv.org/pinchartl/media.git/commit/d3abafde0277f168df0b2912
>>> b5d84550590d80b2
>>
>> According to the comments on the IOMMU/DT patches [1], some work is still
>> needed to merge these patches, mainly to support other IOMMUs (OMAP4,
>> OMAP5).
> 
> Sure, the code need to be reworked, but I believe it's going in the right 
> direction and shouldn't be too complex to fix.
> 
>> So the current base is probably ok. I will resume my work on this soon.
> 
> Great, thanks.
> 
>> What are your comments on patch 1?
> 
> I just agree with Suman that there can be multiple IOMMUs and that the 
> bus_set_iommu() call should thus be kept in the init function. The current 
> infrastructure allows multiple IOMMUs to coexist as long as they're of the 
> same type (I'm pretty sure we'll have to fix that at some point). I believe 
> the problem that patch 1/7 tries to fix is actually the right behaviour.
> 

Yes I agree also with Suman, even if I do not really like the current
"trick". With the move to DT, we can probably use something like
<phandle> <-> consumer relations to improve this.

>> I briefly looked at your fix, seems ok to me. I do not figure out how it
>> worked for me.
> 
> I was puzzled by that as well :-)
> 

Will dig into this next week as well.

Regards,

Florian