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

From: "Guzman Lugo, Fernando" <fernando.lugo@ti.com>
To: Felipe Contreras <felipe.contreras@gmail.com>
Cc: "Kanigeri, Hari" <h-kanigeri2@ti.com>,
	"linux-omap@vger.kernel.org" <linux-omap@vger.kernel.org>,
	"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
	"ohad@wizery.com" <ohad@wizery.com>,
	"hiroshi.doyu@nokia.com" <hiroshi.doyu@nokia.com>,
	"ameya.palande@nokia.com" <ameya.palande@nokia.com>,
	"felipe.contreras@nokia.com" <felipe.contreras@nokia.com>
Subject: RE: [PATCH 8/9] dspbridge: add map support for big buffers
Date: Tue, 24 Aug 2010 13:44:27 -0500	[thread overview]
Message-ID: <496565EC904933469F292DDA3F1663E602F0FA397F@dlee06.ent.ti.com> (raw)
In-Reply-To: <AANLkTi=NuPu6bvv6KF7sXRp02bvfz7oRkG1SG1PstA-H@mail.gmail.com>

> -----Original Message-----
> From: Felipe Contreras [mailto:felipe.contreras@gmail.com] 
> Sent: Tuesday, August 24, 2010 12:46 PM
> To: Guzman Lugo, Fernando
> Cc: Kanigeri, Hari; linux-omap@vger.kernel.org; 
> linux-kernel@vger.kernel.org; ohad@wizery.com; 
> hiroshi.doyu@nokia.com; ameya.palande@nokia.com; 
> felipe.contreras@nokia.com
> Subject: Re: [PATCH 8/9] dspbridge: add map support for big buffers
> 
> On Tue, Aug 24, 2010 at 7:31 PM, Guzman Lugo, Fernando 
> <fernando.lugo@ti.com> wrote:
> >
> >
> >> -----Original Message-----
> >> From: Felipe Contreras [mailto:felipe.contreras@gmail.com]
> >> Sent: Tuesday, August 24, 2010 5:09 AM
> >> To: Guzman Lugo, Fernando
> >> Cc: Kanigeri, Hari; linux-omap@vger.kernel.org; 
> >> linux-kernel@vger.kernel.org; ohad@wizery.com; 
> >> hiroshi.doyu@nokia.com; ameya.palande@nokia.com; 
> >> felipe.contreras@nokia.com
> >> 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@ti.com> 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.

Yeah, DMM removal does not depend on iommu migration. However,
After the changes for iommu migration the DMM module is not
Needed anymore, so it is better to remove it too.

Regards,
Fernando.

> 
> --
> Felipe Contreras
> 