Subject: [PATCH 3/6] ARM: OMAP2+: Move plat/iovmm.h to include/linux/omap-iommu.h

From: [email-masked] (Tony Lindgren)
Date: Thu, 25 Oct 2012 14:39:35 -0700

* Laurent Pinchart <[email-masked]> [121025 13:23]:
> Hi Tony,
> 
> On Thursday 25 October 2012 09:56:44 Tony Lindgren wrote:
> > * Laurent Pinchart <[email-masked]> [121025 01:39]:
> > > I still think you should split this in two files, omap-iommu.h and omap-
> > > iovmm.h. The later would just be arch/arm/plat-omap/include/plat/iovmm.h
> > > moved to include/linux.h.
> > 
> > Can you please explain a bit more why you're thinking a separate
> > omap-iovmm.h is needed in addtion to omap-iommu.h?
> 
> The IOVMM API is layered top of the IOMMU API. It's really a separate API, so 
> two header files make sense. This patch creates a hybrid omap-iommu.h header 
> with mixed definitions, it just doesn't feel right :-) I won't insist for a 
> split though, if you think it's better to have a single header we can keep it 
> that way.

Yes it's true it's a separate layer. But it's still iommu
specific. The functions exported by omap-iovmm.c have iommu_
prefix in the name except for one:

drivers/iommu/omap-iovmm.c:EXPORT_SYMBOL_GPL(omap_find_iovm_area);
drivers/iommu/omap-iovmm.c:EXPORT_SYMBOL_GPL(omap_da_to_va);
drivers/iommu/omap-iovmm.c:EXPORT_SYMBOL_GPL(omap_iommu_vmap);
drivers/iommu/omap-iovmm.c:EXPORT_SYMBOL_GPL(omap_iommu_vunmap);
drivers/iommu/omap-iovmm.c:EXPORT_SYMBOL_GPL(omap_iommu_vmalloc);
drivers/iommu/omap-iovmm.c:EXPORT_SYMBOL_GPL(omap_iommu_vfree);

So it should be OK to keep it all in omap-iommu.h file. Let's 
see hear what..

> > My reasoning for not adding it is that neither intel nor amd needs
> > more than intel-iommu.h and amd-iommu.h. And hopefully the iommu
> > framework will eventually provide the API needed. And I'd rather
> > not be the person introducing this second new file into
> > include/linux :)
> > 
> > Joerg and Ohad, do you have any opinions on this?

..Joerg and Ohad say.

Regards,

Tony