Re: [PATCH v7 06/07] iommu/ipmmu-vmsa: ARM and ARM64 archdata access

From: Magnus Damm
Date: Wed Mar 08 2017 - 22:44:37 EST

Hi Robin,

On Wed, Mar 8, 2017 at 9:48 PM, Robin Murphy <robin.murphy@xxxxxxx> wrote:
> On 07/03/17 03:17, Magnus Damm wrote:
>> From: Magnus Damm <damm+renesas@xxxxxxxxxxxxx>
>> Not all architectures have an iommu member in their archdata, so
>> use #ifdefs support build with COMPILE_TEST on any architecture.
> I have a feeling I might be repeating myself, but ipmmu_vmsa_archdata
> looks to be trivially convertible to iommu_fwspec, which I strongly
> encourage, not least because it would obviate bodges like this.

Yeah, I think it should be possible to use iommu_fwspec for this
purpose. The question is when to do it. =)

I actually looked into it recently, but then realised that for this to
work then due to code sharing I need to make use of iommu_fwspec on
both 32-bit and 64-bit ARM. So it requires rework of the existing
IPMMU for 32-bit ARM (including hairy legacy CONFIG_IOMMU_DMA=n code).
I was actually thinking of doing some rework of 32-bit ARM IPMMU code
anyway (I suspect iommu_device_* conversion caused breakage) and it
probably has to happen on top of current -next. I would also like to
start reducing burden of forward porting all these patches, and
stirring up the ground does not really help much there...


/ magnus