From: Hiroshi Doyu <hdoyu@nvidia.com>
To: "joro@8bytes.org" <joro@8bytes.org>
Cc: "iommu@lists.linux-foundation.org"
<iommu@lists.linux-foundation.org>,
"linux-arm-kernel@lists.infradead.org"
<linux-arm-kernel@lists.infradead.org>,
"linux-tegra@vger.kernel.org" <linux-tegra@vger.kernel.org>,
"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
"linaro-mm-sig-bounces@lists.linaro.org"
<linaro-mm-sig-bounces@lists.linaro.org>
Subject: Re: [PATCH 2/2] ARM: IOMMU: Tegra30: Add iommu_ops for SMMU driver
Date: Tue, 24 Jan 2012 14:41:21 +0100 [thread overview]
Message-ID: <20120124.154121.1062920821192552748.hdoyu@nvidia.com> (raw)
In-Reply-To: <20120123154310.GC6269@8bytes.org>
From: Joerg Roedel <joro@8bytes.org>
Subject: Re: [PATCH 2/2] ARM: IOMMU: Tegra30: Add iommu_ops for SMMU driver
Date: Mon, 23 Jan 2012 16:43:10 +0100
Message-ID: <20120123154310.GC6269@8bytes.org>
> > + }
> > +
> > + spin_unlock_irqrestore(&as->lock, flags);
> > +
> > + domain->priv = NULL;
> > + dev_dbg(smmu->dev, "smmu_as@%p\n", as);
> > +}
> > +
> > +static int smmu_iommu_attach_dev(struct iommu_domain *domain,
> > + struct device *dev)
> > +{
> > + struct smmu_as *as = domain->priv;
> > + struct smmu_device *smmu = as->smmu;
>
> Hmm, this looks like there is a 1-1 mapping between hardware SMMU
> devices and domains. This is not consistent with IOMMU-API semantics
> where a domain can contain devices behind different SMMUs. Please fix
> that.
Actually I really like the concept of this "domain" now, which hides
the H/W hierarchy from users.
But in Tegra SMMU/GART case, there's a single one IOMMU device in the
system. Keeping a iommu device list in a domain and iterating iommu
device list in each iommu_ops seem to be so nice, but I'm afraid that
this may be a bit too much when one already knows that there's only
one IOMMU device in the system.
If there's no actual problem for 1-1 mapping between IOMMU H/Ws and
domains, I think that it may not so bad to keep the original code(1-1)
for GART and SMMU. What do you think?
next prev parent reply other threads:[~2012-01-24 13:41 UTC|newest]
Thread overview: 25+ messages / expand[flat|nested] mbox.gz Atom feed top
2012-01-05 7:11 [PATCH v3 0/2] ARM: IOMMU: tegra: Add iommu_ops for GART/SMMU driver Hiroshi DOYU
2012-01-05 7:11 ` [PATCH 1/2] ARM: IOMMU: Tegra20: Add iommu_ops for GART driver Hiroshi DOYU
2012-01-23 15:00 ` Joerg Roedel
2012-01-25 7:40 ` Hiroshi Doyu
2012-01-26 11:58 ` joro
2012-01-26 14:45 ` Hiroshi Doyu
2012-01-05 7:11 ` [PATCH 2/2] ARM: IOMMU: Tegra30: Add iommu_ops for SMMU driver Hiroshi DOYU
2012-01-23 15:43 ` Joerg Roedel
2012-01-24 9:57 ` Hiroshi Doyu
2012-01-24 11:04 ` Joerg Roedel
2012-01-24 11:36 ` Hiroshi Doyu
2012-01-24 11:57 ` joerg.roedel
2012-01-24 12:07 ` Hiroshi Doyu
2012-01-24 13:41 ` Hiroshi Doyu [this message]
2012-01-24 13:46 ` Felipe Balbi
2012-01-24 14:25 ` joro
2012-01-25 7:39 ` Hiroshi Doyu
2012-01-26 14:59 ` joro
2012-01-05 7:17 ` [PATCH v3 0/2] ARM: IOMMU: tegra: Add iommu_ops for GART/SMMU driver Hiroshi Doyu
2012-01-05 12:53 ` Russell King - ARM Linux
2012-01-05 14:29 ` Hiroshi Doyu
2012-01-05 14:46 ` Russell King - ARM Linux
2012-01-11 14:24 ` Hiroshi Doyu
2012-01-09 0:39 ` KyongHo Cho
2012-01-09 11:45 ` Russell King - ARM Linux
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