Re: [PATCH 8/9] dspbridge: add map support for big buffers

From: Felipe Contreras
Date: Tue Aug 24 2010 - 13:46:33 EST


On Tue, Aug 24, 2010 at 7:31 PM, Guzman Lugo, Fernando
<fernando.lugo@xxxxxx> wrote:
>
>
>> -----Original Message-----
>> From: Felipe Contreras [mailto:felipe.contreras@xxxxxxxxx]
>> Sent: Tuesday, August 24, 2010 5:09 AM
>> To: Guzman Lugo, Fernando
>> Cc: Kanigeri, Hari; linux-omap@xxxxxxxxxxxxxxx;
>> linux-kernel@xxxxxxxxxxxxxxx; ohad@xxxxxxxxxx;
>> hiroshi.doyu@xxxxxxxxx; ameya.palande@xxxxxxxxx;
>> felipe.contreras@xxxxxxxxx
>> Subject: Re: [PATCH 8/9] dspbridge: add map support for big buffers
>>
>> On Fri, Jul 2, 2010 at 9:39 PM, Guzman Lugo, Fernando
>> <fernando.lugo@xxxxxx> wrote:
>> > I think, it would be good if we get rid of DMMPOOL size, if
>> the liked list grow up as it is needed, there is no memory
>> penalty of have all the possible iommu addresses valid
>> (11000000 - FFFFFFFF). The reservation will only fail when
>> there is no memory. If a software restriction is needed we
>> could define a start and end addresses for iommu module
>> (maybe as a parameter when the iommu handle for iva2 is got)
>> and that boundaries can be taking in account at the moment of
>> reserve the memory.
>>
>> What happened to this?
>>
>> IIUC what you are proposing is to remove the DMM pool
>> completely, that makes sense to me. However, is it really
>> needed to finish the iommu migration to do this?
>>
>> > I think the reserve/unreserved dspbridge api can disappear
>> and just return the da address in the map function.
>>
>> This is something I've proposed before, so I agree :)
>
> Yeah, that is how it will be. I have been busy with other stuffs, but now
> I have finish a version with all dmm module removed and reserve/unreserve
> Api removed as well. But because a the big # of patches merge in dspbrdge
> I have to rebase them to the latest, I hope finish this week and send
> Them again next week.

Awesome :)

However, I still have the question about the dependency on iommu;
AFAICS the DMM removal doesn't depend on the migration to iommu, which
AFAIK has been stalled for some time.

--
Felipe Contreras
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