Re: [PATCH v7 3/3] iommu/tegra-smmu: Add PCI support

Robin Murphy
2020-10-14T17:42:41Z

On 2020-10-09 17:19, Nicolin Chen wrote:
> This patch simply adds support for PCI devices.
>
> Reviewed-by: Dmitry Osipenko <digetx@gmail.com>
> Tested-by: Dmitry Osipenko <digetx@gmail.com>
> Signed-off-by: Nicolin Chen <nicoleotsuka@gmail.com>
> ---
>
> Changelog
> v6->v7
> * Renamed goto labels, suggested by Thierry.
> v5->v6
> * Added Dmitry's Reviewed-by and Tested-by.
> v4->v5
> * Added Dmitry's Reviewed-by
> v3->v4
> * Dropped !iommu_present() check
> * Added CONFIG_PCI check in the exit path
> v2->v3
> * Replaced ternary conditional operator with if-else in .device_group()
> * Dropped change in tegra_smmu_remove()
> v1->v2
> * Added error-out labels in tegra_smmu_probe()
> * Dropped pci_request_acs() since IOMMU core would call it.
>
> drivers/iommu/tegra-smmu.c | 35 +++++++++++++++++++++++++----------
> 1 file changed, 25 insertions(+), 10 deletions(-)
>
> diff --git a/drivers/iommu/tegra-smmu.c b/drivers/iommu/tegra-smmu.c
> index be29f5977145..2941d6459076 100644
> --- a/drivers/iommu/tegra-smmu.c
> +++ b/drivers/iommu/tegra-smmu.c
> @@ -10,6 +10,7 @@
> #include <linux/kernel.h>
> #include <linux/of.h>
> #include <linux/of_device.h>
> +#include <linux/pci.h>
> #include <linux/platform_device.h>
> #include <linux/slab.h>
> #include <linux/spinlock.h>
> @@ -865,7 +866,11 @@ static struct iommu_group *tegra_smmu_device_group(struct device *dev)
> group->smmu = smmu;
> group->soc = soc;
>
> - group->group = iommu_group_alloc();
> + if (dev_is_pci(dev))
> + group->group = pci_device_group(dev);

Just to check, is it OK to have two or more swgroups "owning" the same
iommu_group if an existing one gets returned here? It looks like that
might not play nice with the use of iommu_group_set_iommudata().

Robin.

> + else
> + group->group = generic_device_group(dev);
> +
> if (IS_ERR(group->group)) {
> devm_kfree(smmu->dev, group);
> mutex_unlock(&smmu->lock);
> @@ -1075,22 +1080,32 @@ struct tegra_smmu *tegra_smmu_probe(struct device *dev,
> iommu_device_set_fwnode(&smmu->iommu, dev->fwnode);
>
> err = iommu_device_register(&smmu->iommu);
> - if (err) {
> - iommu_device_sysfs_remove(&smmu->iommu);
> - return ERR_PTR(err);
> - }
> + if (err)
> + goto remove_sysfs;
>
> err = bus_set_iommu(&platform_bus_type, &tegra_smmu_ops);
> - if (err < 0) {
> - iommu_device_unregister(&smmu->iommu);
> - iommu_device_sysfs_remove(&smmu->iommu);
> - return ERR_PTR(err);
> - }
> + if (err < 0)
> + goto unregister;
> +
> +#ifdef CONFIG_PCI
> + err = bus_set_iommu(&pci_bus_type, &tegra_smmu_ops);
> + if (err < 0)
> + goto unset_platform_bus;
> +#endif
>
> if (IS_ENABLED(CONFIG_DEBUG_FS))
> tegra_smmu_debugfs_init(smmu);
>
> return smmu;
> +
> +unset_platform_bus: __maybe_unused;
> + bus_set_iommu(&platform_bus_type, NULL);
> +unregister:
> + iommu_device_unregister(&smmu->iommu);
> +remove_sysfs:
> + iommu_device_sysfs_remove(&smmu->iommu);
> +
> + return ERR_PTR(err);
> }
>
> void tegra_smmu_remove(struct tegra_smmu *smmu)
>