From: Nicolin Chen <nicoleotsuka@gmail.com>
To: Dmitry Osipenko <digetx@gmail.com>
Cc: linux-kernel@vger.kernel.org, iommu@lists.linux-foundation.org,
krzk@kernel.org, jonathanh@nvidia.com,
Thierry Reding <thierry.reding@gmail.com>,
linux-tegra@vger.kernel.org
Subject: Re: [PATCH v3 2/3] iommu/tegra-smmu: Rework .probe_device and .attach_dev
Date: Wed, 30 Sep 2020 18:26:30 -0700 [thread overview]
Message-ID: <20201001012630.GA28240@Asurada-Nvidia> (raw)
In-Reply-To: <5945a63e-79d8-e3ae-ab53-cee8c220ac7d@gmail.com>
On Thu, Oct 01, 2020 at 12:56:46AM +0300, Dmitry Osipenko wrote:
> 01.10.2020 00:32, Nicolin Chen пишет:
> > On Thu, Oct 01, 2020 at 12:24:25AM +0300, Dmitry Osipenko 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.
> >>>>
> >>>> Once we have that we can still iterate over the iommus property and do
> >>>> not need to rely on this global variable.
> >>>
> >>> I agree that it'd work. But I was hoping to simplify the code
> >>> here if it's possible. Looks like we have an argument on this
> >>> so I will choose to go with your suggestion above for now.
> >>
> >> This patch removed more lines than were added. If this will be opposite
> >> for the Thierry's suggestion, then it's probably not a great suggestion.
> >
> > Sorry, I don't quite understand this comments. Would you please
> > elaborate what's this "it" being "not a great suggestion"?
> >
>
> I meant that you should try to implement Thierry's solution, but if the
> end result will be worse than the current patch, then you shouldn't make
> a v4, but get back to this discussion in order to choose the best option
> and make everyone agree on it.
I see. Thanks for the reply. And here is a sample implementation:
@@ -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;
+}
+
static struct iommu_device *tegra_smmu_probe_device(struct device *dev)
{
struct device_node *np = dev->of_node;
@@ -843,11 +860,14 @@ static struct iommu_device *tegra_smmu_probe_device(struct device *dev)
unsigned int index = 0;
int err;
+ if (dev_is_pci(dev))
+ np = tegra_smmu_find_pci_np(to_pci_dev(dev));
+
while (of_parse_phandle_with_args(np, "iommus", "#iommu-cells", index,
&args) == 0) {
smmu = tegra_smmu_find(args.np);
if (smmu) {
- err = tegra_smmu_configure(smmu, dev, &args);
+ err = tegra_smmu_configure(smmu, dev, &args, &np->fwnode);
of_node_put(args.np);
if (err < 0)
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next prev parent reply other threads:[~2020-10-01 1:32 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 [this message]
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
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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