From: Nicolin Chen <nicoleotsuka@gmail.com>
To: Thierry Reding <thierry.reding@gmail.com>
Cc: linux-kernel@vger.kernel.org, iommu@lists.linux-foundation.org,
krzk@kernel.org, jonathanh@nvidia.com,
linux-tegra@vger.kernel.org, Dmitry Osipenko <digetx@gmail.com>
Subject: Re: [PATCH v3 2/3] iommu/tegra-smmu: Rework .probe_device and .attach_dev
Date: Thu, 1 Oct 2020 03:33:19 -0700 [thread overview]
Message-ID: <20201001103318.GA1272@Asurada> (raw)
In-Reply-To: <20201001095152.GD3919720@ulmo>
On Thu, Oct 01, 2020 at 11:51:52AM +0200, Thierry Reding wrote:
> > > >> ...
> > > >>>> It looks to me like the only reason why you need this new global API is
> > > >>>> because PCI devices may not have a device tree node with a phandle to
> > > >>>> the IOMMU. However, SMMU support for PCI will only be enabled if the
> > > >>>> root complex has an iommus property, right? In that case, can't we
> > > >>>> simply do something like this:
> > > >>>>
> > > >>>> if (dev_is_pci(dev))
> > > >>>> np = find_host_bridge(dev)->of_node;
> > > >>>> else
> > > >>>> np = dev->of_node;
> > > >>>>
> > > >>>> ? I'm not sure exactly what find_host_bridge() is called, but I'm pretty
> > > >>>> sure that exists.
> > @@ -814,12 +815,15 @@ static struct tegra_smmu *tegra_smmu_find(struct device_node *np)
> > }
> >
> > static int tegra_smmu_configure(struct tegra_smmu *smmu, struct device *dev,
> > - struct of_phandle_args *args)
> > + struct of_phandle_args *args, struct fwnode_handle *fwnode)
> > {
> > const struct iommu_ops *ops = smmu->iommu.ops;
> > int err;
> >
> > - err = iommu_fwspec_init(dev, &dev->of_node->fwnode, ops);
> > + if (!fwnode)
> > + return -ENOENT;
> > +
> > + err = iommu_fwspec_init(dev, fwnode, ops);
> > if (err < 0) {
> > dev_err(dev, "failed to initialize fwspec: %d\n", err);
> > return err;
> > @@ -835,6 +839,19 @@ static int tegra_smmu_configure(struct tegra_smmu *smmu, struct device *dev,
> > return 0;
> > }
> >
> > +static struct device_node *tegra_smmu_find_pci_np(struct pci_dev *pci_dev)
> > +{
> > + struct pci_bus *bus = pci_dev->bus;
> > + struct device *dev = &bus->dev;
> > +
> > + while (!of_property_read_bool(dev->of_node, "iommus") && bus->parent) {
> > + dev = &bus->parent->dev;
> > + bus = bus->parent;
> > + }
> > +
> > + return dev->of_node;
> > +}
>
> This seems like it's the equivalent of pci_get_host_bridge_device(). Can
> you use that instead? I think you might use the parent of the host
> bridge that's returned from that function, though.
I noticed that one when looking up one of the of_ functions, yet
also found that this pci_get_host_bridge_device() is privated by
https://git.kernel.org/pub/scm/linux/kernel/git/next/linux-next.git/commit/drivers/pci/pci.h?id=975e1ac173058b8710e5979e97fc1397233301f3
Would PCI folks be that willing to (allow to) revert it?
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next prev parent reply other threads:[~2020-10-01 10:33 UTC|newest]
Thread overview: 66+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-09-30 8:42 [PATCH v3 0/3] iommu/tegra-smmu: Add PCI support Nicolin Chen
2020-09-30 8:42 ` [PATCH v3 1/3] memory: tegra: Add devm_tegra_get_memory_controller() Nicolin Chen
2020-09-30 9:07 ` Krzysztof Kozlowski
2020-09-30 9:41 ` Nicolin Chen
2020-09-30 10:27 ` Krzysztof Kozlowski
2020-09-30 14:41 ` Dmitry Osipenko
2020-09-30 14:45 ` Krzysztof Kozlowski
2020-09-30 15:22 ` Dmitry Osipenko
2020-09-30 15:23 ` Thierry Reding
2020-09-30 15:27 ` Dmitry Osipenko
2020-09-30 15:53 ` Dmitry Osipenko
2020-09-30 16:03 ` Thierry Reding
2020-09-30 16:06 ` Dmitry Osipenko
2020-09-30 16:15 ` Thierry Reding
2020-09-30 16:26 ` Dmitry Osipenko
2020-09-30 16:38 ` Thierry Reding
2020-09-30 17:32 ` Dmitry Osipenko
2020-09-30 8:42 ` [PATCH v3 2/3] iommu/tegra-smmu: Rework .probe_device and .attach_dev Nicolin Chen
2020-09-30 9:21 ` Krzysztof Kozlowski
2020-09-30 9:40 ` Nicolin Chen
2020-09-30 10:19 ` Krzysztof Kozlowski
2020-09-30 14:41 ` Dmitry Osipenko
2020-09-30 15:09 ` Dmitry Osipenko
2020-09-30 20:51 ` Nicolin Chen
2020-09-30 15:31 ` Thierry Reding
2020-09-30 15:36 ` Dmitry Osipenko
2020-09-30 16:06 ` Thierry Reding
2020-09-30 16:25 ` Dmitry Osipenko
2020-09-30 16:47 ` Thierry Reding
2020-10-01 2:11 ` Dmitry Osipenko
2020-10-01 7:58 ` Thierry Reding
2020-10-01 19:04 ` Dmitry Osipenko
2020-10-05 9:16 ` Thierry Reding
2020-10-05 9:38 ` Dmitry Osipenko
2020-10-05 10:27 ` Thierry Reding
2020-09-30 16:10 ` Thierry Reding
2020-09-30 16:29 ` Dmitry Osipenko
2020-10-01 7:59 ` Thierry Reding
2020-09-30 20:36 ` Nicolin Chen
2020-09-30 21:24 ` Dmitry Osipenko
2020-09-30 21:32 ` Nicolin Chen
2020-09-30 21:56 ` Dmitry Osipenko
2020-10-01 1:26 ` Nicolin Chen
2020-10-01 2:06 ` Dmitry Osipenko
2020-10-01 2:48 ` Nicolin Chen
2020-10-01 4:04 ` Dmitry Osipenko
2020-10-01 10:23 ` Thierry Reding
2020-10-01 11:04 ` Nicolin Chen
2020-10-01 20:33 ` Dmitry Osipenko
2020-10-02 1:07 ` Nicolin Chen
2020-10-02 1:55 ` Dmitry Osipenko
2020-10-02 2:54 ` Nicolin Chen
2020-10-05 7:24 ` Thierry Reding
2020-10-05 7:13 ` Thierry Reding
2020-10-05 8:14 ` Dmitry Osipenko
2020-10-05 9:31 ` Thierry Reding
2020-10-01 9:54 ` Thierry Reding
2020-10-01 9:51 ` Thierry Reding
2020-10-01 10:33 ` Nicolin Chen [this message]
2020-10-01 10:42 ` Thierry Reding
2020-10-01 9:47 ` Thierry Reding
2020-10-01 10:46 ` Thierry Reding
2020-10-02 1:29 ` Nicolin Chen
2020-09-30 8:42 ` [PATCH v3 3/3] iommu/tegra-smmu: Add PCI support Nicolin Chen
2020-09-30 14:53 ` Dmitry Osipenko
2020-09-30 20:03 ` Nicolin Chen
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