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From: will.deacon@arm•com (Will Deacon)
To: linux-arm-kernel@lists•infradead.org
Subject: [PATCH 3/6] iommu/arm-smmu: add support for iova_to_phys through ATS1PR
Date: Mon, 1 Sep 2014 17:15:09 +0100	[thread overview]
Message-ID: <20140901161509.GI24594@arm.com> (raw)
In-Reply-To: <20140826135451.GQ23445@arm.com>

On Tue, Aug 26, 2014 at 02:54:51PM +0100, Will Deacon wrote:
> On Tue, Aug 19, 2014 at 07:12:41PM +0100, Mitchel Humpherys wrote:
> > On Tue, Aug 19 2014 at 05:44:32 AM, Will Deacon <will.deacon@arm•com> wrote:
> > >> @@ -2005,6 +2073,11 @@ int arm_smmu_device_cfg_probe(struct arm_smmu_device *smmu)
> > >>  		return -ENODEV;
> > >>  	}
> > >>  
> > >> +	if (smmu->version == 1 || (!(id & ID0_ATOSNS) && (id & ID0_S1TS))) {
> > >
> > > Are you sure about this? The v2 spec says that is ATOSNS is clear then S1TS
> > > is also clear.
> > 
> > I was looking at Section 4.1.1 of ARM IHI 0062C ID091613 which states:
> > 
> >     In SMMUv2, the address translation registers are OPTIONAL. The
> >     address translation registers are implemented only when both:
> > 
> >         o The SMMU_IDR0.S1TS bit is set to 1.
> >         o The SMMU_IDR0.ATOSNS bit is set to 0.
> > 
> > I assume you're referring to section 9.6.1 of the same document:
> > 
> >     ATOSNS, bit[26]
> >     Address Translation Operations Not Supported. The possible values of
> >     this bit are:
> > 
> >         0 Address translation operations are supported. Stage 1
> >           translation is not supported, that is, the S1TS bit is set to 0.
> > 
> >         1 Address translation operations are not supported. Stage 1
> >           translation is supported, that is, the S1TS bit is set to 1.
> > 
> > If that really means that S1TS and ATOSNS always have the same value
> > then Section 4.1.1 doesn't make any sense. Or am I missing something?
> 
> I'll get this checked, as those two paragraphs don't make an awful lot of
> sense together.

Right, word from above says that ATOS is implemented iff:

  IDR0.S1TS == 1 && IDR0.ATOSNS == 0

Basically, ATOS only works for stage-1 when it's present, so that explains
the dependency. Looking at the piece of diff at the top of this mail, I
think that means your code is correct

Will

  reply	other threads:[~2014-09-01 16:15 UTC|newest]

Thread overview: 34+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2014-08-13  0:51 [PATCH 0/6] iommu/arm-smmu: misc features, new DT bindings Mitchel Humpherys
2014-08-13  0:51 ` [PATCH 1/6] iommu/arm-smmu: add support for specifying clocks Mitchel Humpherys
2014-08-13 21:07   ` Mitchel Humpherys
2014-08-19 12:58   ` Will Deacon
2014-08-19 19:03     ` Olav Haugan
2014-08-26 14:27       ` Will Deacon
2014-09-10  1:29         ` Mitchel Humpherys
2014-09-10 18:27           ` Will Deacon
2014-09-10 19:09             ` Mitchel Humpherys
2014-09-15 18:38               ` Mitchel Humpherys
2014-08-19 19:28     ` Mitchel Humpherys
2014-08-13  0:51 ` [PATCH 2/6] iommu/arm-smmu: add support for specifying regulators Mitchel Humpherys
2014-08-13 21:17   ` Mitchel Humpherys
2014-08-19 13:00   ` Will Deacon
2014-08-13  0:51 ` [PATCH 3/6] iommu/arm-smmu: add support for iova_to_phys through ATS1PR Mitchel Humpherys
2014-08-19 12:44   ` Will Deacon
2014-08-19 18:12     ` Mitchel Humpherys
2014-08-26 13:54       ` Will Deacon
2014-09-01 16:15         ` Will Deacon [this message]
2014-08-13  0:51 ` [PATCH 4/6] iommu/arm-smmu: implement generic DT bindings Mitchel Humpherys
2014-08-13 16:53   ` Mitchel Humpherys
2014-08-19 12:54   ` Will Deacon
2014-08-19 15:54     ` Hiroshi Doyu
2014-08-20  3:18     ` Arnd Bergmann
2014-08-13  0:51 ` [PATCH 5/6] iommu/arm-smmu: support buggy implementations with invalidate-on-map Mitchel Humpherys
2014-11-12 18:26   ` Will Deacon
2014-11-12 18:58     ` Mitchel Humpherys
2014-11-13  9:48       ` Will Deacon
2014-11-14 23:08         ` Mitchel Humpherys
2014-08-13  0:51 ` [PATCH 6/6] iommu/arm-smmu: add .domain_{set, get}_attr for coherent walk control Mitchel Humpherys
2014-08-19 12:48   ` [PATCH 6/6] iommu/arm-smmu: add .domain_{set,get}_attr " Will Deacon
2014-08-19 19:19     ` [PATCH 6/6] iommu/arm-smmu: add .domain_{set, get}_attr " Mitchel Humpherys
2014-08-13 17:22 ` [PATCH 0/6] iommu/arm-smmu: misc features, new DT bindings Mitchel Humpherys
2014-08-15 17:25   ` Will Deacon

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