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[4/5] iommu/tegra-smmu: Add PCI support

Message ID 20200926080719.6822-5-nicoleotsuka@gmail.com
State New
Headers show
Series iommu/tegra-smmu: Adding PCI support and mappings debugfs node | expand

Commit Message

Nicolin Chen Sept. 26, 2020, 8:07 a.m. UTC
This patch simply adds support for PCI devices.

Signed-off-by: Nicolin Chen <nicoleotsuka@gmail.com>
---
 drivers/iommu/tegra-smmu.c | 17 ++++++++++++++++-
 1 file changed, 16 insertions(+), 1 deletion(-)

Comments

Dmitry Osipenko Sept. 26, 2020, 10:18 p.m. UTC | #1
26.09.2020 11:07, Nicolin Chen пишет:
...
> +#ifdef CONFIG_PCI
> +	if (!iommu_present(&pci_bus_type)) {

Is this iommu_present() check really needed?

> +		pci_request_acs();

Shouldn't pci_request_acs() be invoked *after* bus_set_iommu() succeeds?

> +		err = bus_set_iommu(&pci_bus_type, &tegra_smmu_ops);
> +		if (err < 0) {
> +			bus_set_iommu(&platform_bus_type, NULL);
> +			iommu_device_unregister(&smmu->iommu);
> +			iommu_device_sysfs_remove(&smmu->iommu);
> +			return ERR_PTR(err);
> +		}
> +	}
> +#endif
> +
>  	if (IS_ENABLED(CONFIG_DEBUG_FS))
>  		tegra_smmu_debugfs_init(smmu);
>  
>
Thierry Reding Sept. 28, 2020, 7:55 a.m. UTC | #2
On Sat, Sep 26, 2020 at 01:07:18AM -0700, Nicolin Chen wrote:
> This patch simply adds support for PCI devices.
> 
> Signed-off-by: Nicolin Chen <nicoleotsuka@gmail.com>
> ---
>  drivers/iommu/tegra-smmu.c | 17 ++++++++++++++++-
>  1 file changed, 16 insertions(+), 1 deletion(-)
> 
> diff --git a/drivers/iommu/tegra-smmu.c b/drivers/iommu/tegra-smmu.c
> index 97a7185b4578..9dbc5d7183cc 100644
> --- a/drivers/iommu/tegra-smmu.c
> +++ b/drivers/iommu/tegra-smmu.c
> @@ -15,6 +15,7 @@
>  #include <linux/spinlock.h>
>  #include <linux/dma-iommu.h>
>  #include <linux/dma-mapping.h>
> +#include <linux/pci.h>
>  
>  #include <soc/tegra/ahb.h>
>  #include <soc/tegra/mc.h>
> @@ -935,6 +936,7 @@ static struct iommu_group *tegra_smmu_device_group(struct device *dev)
>  	const struct tegra_smmu_group_soc *soc;
>  	struct tegra_smmu_group *group;
>  	int swgroup = fwspec->ids[0];
> +	bool pci = dev_is_pci(dev);
>  	struct iommu_group *grp;
>  
>  	/* Find group_soc associating with swgroup */
> @@ -961,7 +963,7 @@ static struct iommu_group *tegra_smmu_device_group(struct device *dev)
>  	group->smmu = smmu;
>  	group->soc = soc;
>  
> -	group->group = iommu_group_alloc();
> +	group->group = pci ? pci_device_group(dev) : iommu_group_alloc();
>  	if (IS_ERR(group->group)) {
>  		devm_kfree(smmu->dev, group);
>  		mutex_unlock(&smmu->lock);
> @@ -1180,6 +1182,19 @@ struct tegra_smmu *tegra_smmu_probe(struct device *dev,
>  		return ERR_PTR(err);
>  	}
>  
> +#ifdef CONFIG_PCI
> +	if (!iommu_present(&pci_bus_type)) {
> +		pci_request_acs();
> +		err = bus_set_iommu(&pci_bus_type, &tegra_smmu_ops);
> +		if (err < 0) {
> +			bus_set_iommu(&platform_bus_type, NULL);
> +			iommu_device_unregister(&smmu->iommu);
> +			iommu_device_sysfs_remove(&smmu->iommu);
> +			return ERR_PTR(err);

It might be worth factoring out the cleanup code now that there are
multiple failures from which we may need to clean up.

Also, it'd be great if somehow we could do this without the #ifdef,
but I guess since we're using the pci_bus_type global variable directly,
there isn't much we can do here?

Thierry
Nicolin Chen Sept. 28, 2020, 10:31 p.m. UTC | #3
On Sun, Sep 27, 2020 at 01:18:15AM +0300, Dmitry Osipenko wrote:
> 26.09.2020 11:07, Nicolin Chen пишет:
> ...
> > +#ifdef CONFIG_PCI
> > +	if (!iommu_present(&pci_bus_type)) {
> 
> Is this iommu_present() check really needed?
> 
> > +		pci_request_acs();
> 
> Shouldn't pci_request_acs() be invoked *after* bus_set_iommu() succeeds?

Will move it after that. Thanks!
Nicolin Chen Sept. 28, 2020, 10:33 p.m. UTC | #4
On Mon, Sep 28, 2020 at 09:55:45AM +0200, Thierry Reding wrote:
> On Sat, Sep 26, 2020 at 01:07:18AM -0700, Nicolin Chen wrote:
> > +#ifdef CONFIG_PCI
> > +	if (!iommu_present(&pci_bus_type)) {
> > +		pci_request_acs();
> > +		err = bus_set_iommu(&pci_bus_type, &tegra_smmu_ops);
> > +		if (err < 0) {
> > +			bus_set_iommu(&platform_bus_type, NULL);
> > +			iommu_device_unregister(&smmu->iommu);
> > +			iommu_device_sysfs_remove(&smmu->iommu);
> > +			return ERR_PTR(err);
> 
> It might be worth factoring out the cleanup code now that there are
> multiple failures from which we may need to clean up.

Will do.

> Also, it'd be great if somehow we could do this without the #ifdef,
> but I guess since we're using the pci_bus_type global variable directly,
> there isn't much we can do here?

Probably no -- both pci_bus_type and pci_request_acs seem to depend
on it.
diff mbox series

Patch

diff --git a/drivers/iommu/tegra-smmu.c b/drivers/iommu/tegra-smmu.c
index 97a7185b4578..9dbc5d7183cc 100644
--- a/drivers/iommu/tegra-smmu.c
+++ b/drivers/iommu/tegra-smmu.c
@@ -15,6 +15,7 @@ 
 #include <linux/spinlock.h>
 #include <linux/dma-iommu.h>
 #include <linux/dma-mapping.h>
+#include <linux/pci.h>
 
 #include <soc/tegra/ahb.h>
 #include <soc/tegra/mc.h>
@@ -935,6 +936,7 @@  static struct iommu_group *tegra_smmu_device_group(struct device *dev)
 	const struct tegra_smmu_group_soc *soc;
 	struct tegra_smmu_group *group;
 	int swgroup = fwspec->ids[0];
+	bool pci = dev_is_pci(dev);
 	struct iommu_group *grp;
 
 	/* Find group_soc associating with swgroup */
@@ -961,7 +963,7 @@  static struct iommu_group *tegra_smmu_device_group(struct device *dev)
 	group->smmu = smmu;
 	group->soc = soc;
 
-	group->group = iommu_group_alloc();
+	group->group = pci ? pci_device_group(dev) : iommu_group_alloc();
 	if (IS_ERR(group->group)) {
 		devm_kfree(smmu->dev, group);
 		mutex_unlock(&smmu->lock);
@@ -1180,6 +1182,19 @@  struct tegra_smmu *tegra_smmu_probe(struct device *dev,
 		return ERR_PTR(err);
 	}
 
+#ifdef CONFIG_PCI
+	if (!iommu_present(&pci_bus_type)) {
+		pci_request_acs();
+		err = bus_set_iommu(&pci_bus_type, &tegra_smmu_ops);
+		if (err < 0) {
+			bus_set_iommu(&platform_bus_type, NULL);
+			iommu_device_unregister(&smmu->iommu);
+			iommu_device_sysfs_remove(&smmu->iommu);
+			return ERR_PTR(err);
+		}
+	}
+#endif
+
 	if (IS_ENABLED(CONFIG_DEBUG_FS))
 		tegra_smmu_debugfs_init(smmu);