[PATCH 0/5] iommu/tegra-smmu: Adding PCI support and mappings debugfs node

[PATCH 0/5] iommu/tegra-smmu: Adding PCI support and mappings debugfs node

[Nicolin Chen]

This series of patches are some followup patches for tegra-smmu.

There are four parts:
1, PATCH-1 is a clean-up patch for the recently applied SWGROUP change.
2, PATCH-2 fixes a potential race condition
3, PATCH-3/4 adds PCI device support
4, PATCH-5 adds a debugfs node for phys<=>iova mappings

Each of the four parts is sort of functional independent, so we may
apply them separately or incrementally depending on the reviews.

Nicolin Chen (5):
  iommu/tegra-smmu: Unwrap tegra_smmu_group_get
  iommu/tegra-smmu: Expend mutex protection range
  iommu/tegra-smmu: Use iommu_fwspec in .probe_/.attach_device()
  iommu/tegra-smmu: Add PCI support
  iommu/tegra-smmu: Add pagetable mappings to debugfs

 drivers/iommu/tegra-smmu.c | 287 ++++++++++++++++++++++++++++---------
 drivers/memory/tegra/mc.c  |   2 +-
 include/soc/tegra/mc.h     |   2 +
 3 files changed, 221 insertions(+), 70 deletions(-)

-- 
2.17.1

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[PATCH 1/5] iommu/tegra-smmu: Unwrap tegra_smmu_group_get

[Nicolin Chen]

The tegra_smmu_group_get was added to group devices in different
SWGROUPs and it'd return a NULL group pointer upon a mismatch at
tegra_smmu_find_group(), so for most of clients/devices, it very
likely would mismatch and need a fallback generic_device_group().

But now tegra_smmu_group_get handles devices in same SWGROUP too,
which means that it would allocate a group for every new SWGROUP
or would directly return an existing one upon matching a SWGROUP,
i.e. any device will go through this function.

So possibility of having a NULL group pointer in device_group()
is upon failure of either devm_kzalloc() or iommu_group_alloc().
In either case, calling generic_device_group() no longer makes a
sense. Especially for devm_kzalloc() failing case, it'd cause a
problem if it fails at devm_kzalloc() yet succeeds at a fallback
generic_device_group(), because it does not create a group->list
for other devices to match.

This patch simply unwraps the function to clean it up.

Signed-off-by: Nicolin Chen <nicoleotsuka@gmail.com>
---
 drivers/iommu/tegra-smmu.c | 19 ++++---------------
 1 file changed, 4 insertions(+), 15 deletions(-)

diff --git a/drivers/iommu/tegra-smmu.c b/drivers/iommu/tegra-smmu.c
index 0becdbfea306..6335285dc373 100644
--- a/drivers/iommu/tegra-smmu.c
+++ b/drivers/iommu/tegra-smmu.c
@@ -903,11 +903,13 @@ static void tegra_smmu_group_release(void *iommu_data)
 	mutex_unlock(&smmu->lock);
 }
 
-static struct iommu_group *tegra_smmu_group_get(struct tegra_smmu *smmu,
-						unsigned int swgroup)
+static struct iommu_group *tegra_smmu_device_group(struct device *dev)
 {
+	struct iommu_fwspec *fwspec = dev_iommu_fwspec_get(dev);
+	struct tegra_smmu *smmu = dev_iommu_priv_get(dev);
 	const struct tegra_smmu_group_soc *soc;
 	struct tegra_smmu_group *group;
+	int swgroup = fwspec->ids[0];
 	struct iommu_group *grp;
 
 	/* Find group_soc associating with swgroup */
@@ -950,19 +952,6 @@ static struct iommu_group *tegra_smmu_group_get(struct tegra_smmu *smmu,
 	return group->group;
 }
 
-static struct iommu_group *tegra_smmu_device_group(struct device *dev)
-{
-	struct iommu_fwspec *fwspec = dev_iommu_fwspec_get(dev);
-	struct tegra_smmu *smmu = dev_iommu_priv_get(dev);
-	struct iommu_group *group;
-
-	group = tegra_smmu_group_get(smmu, fwspec->ids[0]);
-	if (!group)
-		group = generic_device_group(dev);
-
-	return group;
-}
-
 static int tegra_smmu_of_xlate(struct device *dev,
 			       struct of_phandle_args *args)
 {
-- 
2.17.1

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Re: [PATCH 1/5] iommu/tegra-smmu: Unwrap tegra_smmu_group_get

[Thierry Reding]

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On Sat, Sep 26, 2020 at 01:07:15AM -0700, Nicolin Chen wrote:
> The tegra_smmu_group_get was added to group devices in different
> SWGROUPs and it'd return a NULL group pointer upon a mismatch at
> tegra_smmu_find_group(), so for most of clients/devices, it very
> likely would mismatch and need a fallback generic_device_group().
> 
> But now tegra_smmu_group_get handles devices in same SWGROUP too,
> which means that it would allocate a group for every new SWGROUP
> or would directly return an existing one upon matching a SWGROUP,
> i.e. any device will go through this function.
> 
> So possibility of having a NULL group pointer in device_group()
> is upon failure of either devm_kzalloc() or iommu_group_alloc().
> In either case, calling generic_device_group() no longer makes a
> sense. Especially for devm_kzalloc() failing case, it'd cause a
> problem if it fails at devm_kzalloc() yet succeeds at a fallback
> generic_device_group(), because it does not create a group->list
> for other devices to match.
> 
> This patch simply unwraps the function to clean it up.
> 
> Signed-off-by: Nicolin Chen <nicoleotsuka@gmail.com>
> ---
>  drivers/iommu/tegra-smmu.c | 19 ++++---------------
>  1 file changed, 4 insertions(+), 15 deletions(-)
> 
> diff --git a/drivers/iommu/tegra-smmu.c b/drivers/iommu/tegra-smmu.c
> index 0becdbfea306..6335285dc373 100644
> --- a/drivers/iommu/tegra-smmu.c
> +++ b/drivers/iommu/tegra-smmu.c
> @@ -903,11 +903,13 @@ static void tegra_smmu_group_release(void *iommu_data)
>  	mutex_unlock(&smmu->lock);
>  }
>  
> -static struct iommu_group *tegra_smmu_group_get(struct tegra_smmu *smmu,
> -						unsigned int swgroup)
> +static struct iommu_group *tegra_smmu_device_group(struct device *dev)
>  {
> +	struct iommu_fwspec *fwspec = dev_iommu_fwspec_get(dev);
> +	struct tegra_smmu *smmu = dev_iommu_priv_get(dev);
>  	const struct tegra_smmu_group_soc *soc;
>  	struct tegra_smmu_group *group;
> +	int swgroup = fwspec->ids[0];

This should be unsigned int to match the type of swgroup elsewhere.
Also, it might not be worth having an extra local variable for this
since it's only used once.

Thierry

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Re: [PATCH 1/5] iommu/tegra-smmu: Unwrap tegra_smmu_group_get

[Nicolin Chen]

Hi Thierry,

Thanks for the review.

On Mon, Sep 28, 2020 at 09:13:56AM +0200, Thierry Reding wrote:
> > -static struct iommu_group *tegra_smmu_group_get(struct tegra_smmu *smmu,
> > -						unsigned int swgroup)
> > +static struct iommu_group *tegra_smmu_device_group(struct device *dev)
> >  {
> > +	struct iommu_fwspec *fwspec = dev_iommu_fwspec_get(dev);
> > +	struct tegra_smmu *smmu = dev_iommu_priv_get(dev);
> >  	const struct tegra_smmu_group_soc *soc;
> >  	struct tegra_smmu_group *group;
> > +	int swgroup = fwspec->ids[0];
> 
> This should be unsigned int to match the type of swgroup elsewhere.
> Also, it might not be worth having an extra local variable for this
> since it's only used once.

Will change to unsigned int. There are actually a few places using
it in this function, previously tegra_smmu_group_get().
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[PATCH 2/5] iommu/tegra-smmu: Expend mutex protection range

[Nicolin Chen]

This is used to protect potential race condition at use_count.
since probes of client drivers, calling attach_dev(), may run
concurrently.

Signed-off-by: Nicolin Chen <nicoleotsuka@gmail.com>
---
 drivers/iommu/tegra-smmu.c | 34 +++++++++++++++++++++-------------
 1 file changed, 21 insertions(+), 13 deletions(-)

diff --git a/drivers/iommu/tegra-smmu.c b/drivers/iommu/tegra-smmu.c
index 6335285dc373..b10e02073610 100644
--- a/drivers/iommu/tegra-smmu.c
+++ b/drivers/iommu/tegra-smmu.c
@@ -256,26 +256,19 @@ static int tegra_smmu_alloc_asid(struct tegra_smmu *smmu, unsigned int *idp)
 {
 	unsigned long id;
 
-	mutex_lock(&smmu->lock);
-
 	id = find_first_zero_bit(smmu->asids, smmu->soc->num_asids);
-	if (id >= smmu->soc->num_asids) {
-		mutex_unlock(&smmu->lock);
+	if (id >= smmu->soc->num_asids)
 		return -ENOSPC;
-	}
 
 	set_bit(id, smmu->asids);
 	*idp = id;
 
-	mutex_unlock(&smmu->lock);
 	return 0;
 }
 
 static void tegra_smmu_free_asid(struct tegra_smmu *smmu, unsigned int id)
 {
-	mutex_lock(&smmu->lock);
 	clear_bit(id, smmu->asids);
-	mutex_unlock(&smmu->lock);
 }
 
 static bool tegra_smmu_capable(enum iommu_cap cap)
@@ -420,17 +413,21 @@ static int tegra_smmu_as_prepare(struct tegra_smmu *smmu,
 				 struct tegra_smmu_as *as)
 {
 	u32 value;
-	int err;
+	int err = 0;
+
+	mutex_lock(&smmu->lock);
 
 	if (as->use_count > 0) {
 		as->use_count++;
-		return 0;
+		goto err_unlock;
 	}
 
 	as->pd_dma = dma_map_page(smmu->dev, as->pd, 0, SMMU_SIZE_PD,
 				  DMA_TO_DEVICE);
-	if (dma_mapping_error(smmu->dev, as->pd_dma))
-		return -ENOMEM;
+	if (dma_mapping_error(smmu->dev, as->pd_dma)) {
+		err = -ENOMEM;
+		goto err_unlock;
+	}
 
 	/* We can't handle 64-bit DMA addresses */
 	if (!smmu_dma_addr_valid(smmu, as->pd_dma)) {
@@ -453,24 +450,35 @@ static int tegra_smmu_as_prepare(struct tegra_smmu *smmu,
 	as->smmu = smmu;
 	as->use_count++;
 
+	mutex_unlock(&smmu->lock);
+
 	return 0;
 
 err_unmap:
 	dma_unmap_page(smmu->dev, as->pd_dma, SMMU_SIZE_PD, DMA_TO_DEVICE);
+err_unlock:
+	mutex_unlock(&smmu->lock);
+
 	return err;
 }
 
 static void tegra_smmu_as_unprepare(struct tegra_smmu *smmu,
 				    struct tegra_smmu_as *as)
 {
-	if (--as->use_count > 0)
+	mutex_lock(&smmu->lock);
+
+	if (--as->use_count > 0) {
+		mutex_unlock(&smmu->lock);
 		return;
+	}
 
 	tegra_smmu_free_asid(smmu, as->id);
 
 	dma_unmap_page(smmu->dev, as->pd_dma, SMMU_SIZE_PD, DMA_TO_DEVICE);
 
 	as->smmu = NULL;
+
+	mutex_unlock(&smmu->lock);
 }
 
 static int tegra_smmu_attach_dev(struct iommu_domain *domain,
-- 
2.17.1

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[PATCH 3/5] iommu/tegra-smmu: Use iommu_fwspec in .probe_/.attach_device()

[Nicolin Chen]

The tegra_smmu_probe_device() function searches in DT for the iommu
phandler to get "smmu" pointer. This works for most of SMMU clients
that exist in the DTB. But a PCI device will not be added to iommu,
since it doesn't have a DT node.

Fortunately, for a client with a DT node, tegra_smmu_probe_device()
calls tegra_smmu_of_xlate() via tegra_smmu_configure(), while for a
PCI device, of_pci_iommu_init() in the IOMMU core calls .of_xlate()
as well, even before running tegra_smmu_probe_device(). And in both
cases, tegra_smmu_of_xlate() prepares a valid iommu_fwspec pointer
that allows us to get the mc->smmu pointer via dev_get_drvdata() by
calling driver_find_device_by_fwnode().

So this patch uses iommu_fwspec in .probe_device() and related code
for a client that does not exist in the DTB, especially a PCI one.

Signed-off-by: Nicolin Chen <nicoleotsuka@gmail.com>
---
 drivers/iommu/tegra-smmu.c | 89 +++++++++++++++++++++++---------------
 drivers/memory/tegra/mc.c  |  2 +-
 include/soc/tegra/mc.h     |  2 +
 3 files changed, 56 insertions(+), 37 deletions(-)

diff --git a/drivers/iommu/tegra-smmu.c b/drivers/iommu/tegra-smmu.c
index b10e02073610..97a7185b4578 100644
--- a/drivers/iommu/tegra-smmu.c
+++ b/drivers/iommu/tegra-smmu.c
@@ -13,6 +13,7 @@
 #include <linux/platform_device.h>
 #include <linux/slab.h>
 #include <linux/spinlock.h>
+#include <linux/dma-iommu.h>
 #include <linux/dma-mapping.h>
 
 #include <soc/tegra/ahb.h>
@@ -61,6 +62,8 @@ struct tegra_smmu_as {
 	u32 attr;
 };
 
+static const struct iommu_ops tegra_smmu_ops;
+
 static struct tegra_smmu_as *to_smmu_as(struct iommu_domain *dom)
 {
 	return container_of(dom, struct tegra_smmu_as, domain);
@@ -484,60 +487,49 @@ static void tegra_smmu_as_unprepare(struct tegra_smmu *smmu,
 static int tegra_smmu_attach_dev(struct iommu_domain *domain,
 				 struct device *dev)
 {
+	struct iommu_fwspec *fwspec = dev_iommu_fwspec_get(dev);
 	struct tegra_smmu *smmu = dev_iommu_priv_get(dev);
 	struct tegra_smmu_as *as = to_smmu_as(domain);
-	struct device_node *np = dev->of_node;
-	struct of_phandle_args args;
-	unsigned int index = 0;
-	int err = 0;
-
-	while (!of_parse_phandle_with_args(np, "iommus", "#iommu-cells", index,
-					   &args)) {
-		unsigned int swgroup = args.args[0];
-
-		if (args.np != smmu->dev->of_node) {
-			of_node_put(args.np);
-			continue;
-		}
+	int index, err = 0;
 
-		of_node_put(args.np);
+	if (!fwspec || fwspec->ops != &tegra_smmu_ops)
+		return -ENOENT;
 
+	for (index = 0; index < fwspec->num_ids; index++) {
 		err = tegra_smmu_as_prepare(smmu, as);
-		if (err < 0)
-			return err;
+		if (err)
+			goto err_disable;
 
-		tegra_smmu_enable(smmu, swgroup, as->id);
-		index++;
+		tegra_smmu_enable(smmu, fwspec->ids[index], as->id);
 	}
 
 	if (index == 0)
 		return -ENODEV;
 
 	return 0;
+
+err_disable:
+	for (index--; index >= 0; index--) {
+		tegra_smmu_disable(smmu, fwspec->ids[index], as->id);
+		tegra_smmu_as_unprepare(smmu, as);
+	}
+
+	return err;
 }
 
 static void tegra_smmu_detach_dev(struct iommu_domain *domain, struct device *dev)
 {
+	struct iommu_fwspec *fwspec = dev_iommu_fwspec_get(dev);
 	struct tegra_smmu_as *as = to_smmu_as(domain);
-	struct device_node *np = dev->of_node;
 	struct tegra_smmu *smmu = as->smmu;
-	struct of_phandle_args args;
 	unsigned int index = 0;
 
-	while (!of_parse_phandle_with_args(np, "iommus", "#iommu-cells", index,
-					   &args)) {
-		unsigned int swgroup = args.args[0];
-
-		if (args.np != smmu->dev->of_node) {
-			of_node_put(args.np);
-			continue;
-		}
-
-		of_node_put(args.np);
+	if (!fwspec || fwspec->ops != &tegra_smmu_ops)
+		return;
 
-		tegra_smmu_disable(smmu, swgroup, as->id);
+	for (index = 0; index < fwspec->num_ids; index++) {
+		tegra_smmu_disable(smmu, fwspec->ids[index], as->id);
 		tegra_smmu_as_unprepare(smmu, as);
-		index++;
 	}
 }
 
@@ -845,10 +837,25 @@ static int tegra_smmu_configure(struct tegra_smmu *smmu, struct device *dev,
 	return 0;
 }
 
+static struct tegra_smmu *tegra_smmu_get_by_fwnode(struct fwnode_handle *fwnode)
+{
+	struct device *dev = driver_find_device_by_fwnode(&tegra_mc_driver.driver, fwnode);
+	struct tegra_mc *mc;
+
+	if (!dev)
+		return NULL;
+
+	put_device(dev);
+	mc = dev_get_drvdata(dev);
+
+	return mc->smmu;
+}
+
 static struct iommu_device *tegra_smmu_probe_device(struct device *dev)
 {
 	struct device_node *np = dev->of_node;
 	struct tegra_smmu *smmu = NULL;
+	struct iommu_fwspec *fwspec;
 	struct of_phandle_args args;
 	unsigned int index = 0;
 	int err;
@@ -868,8 +875,6 @@ static struct iommu_device *tegra_smmu_probe_device(struct device *dev)
 			 * supported by the Linux kernel, so abort after the
 			 * first match.
 			 */
-			dev_iommu_priv_set(dev, smmu);
-
 			break;
 		}
 
@@ -877,8 +882,20 @@ static struct iommu_device *tegra_smmu_probe_device(struct device *dev)
 		index++;
 	}
 
-	if (!smmu)
-		return ERR_PTR(-ENODEV);
+	/* Any device should be able to get smmu pointer using fwspec */
+	if (!smmu) {
+		fwspec = dev_iommu_fwspec_get(dev);
+		if (!fwspec || fwspec->ops != &tegra_smmu_ops)
+			return ERR_PTR(-ENODEV);
+
+		smmu = tegra_smmu_get_by_fwnode(fwspec->iommu_fwnode);
+	}
+
+	/* NULL smmu pointer means that SMMU driver is not probed yet */
+	if (unlikely(!smmu))
+		return ERR_PTR(-EPROBE_DEFER);
+
+	dev_iommu_priv_set(dev, smmu);
 
 	return &smmu->iommu;
 }
diff --git a/drivers/memory/tegra/mc.c b/drivers/memory/tegra/mc.c
index ec8403557ed4..4e23fd8d8433 100644
--- a/drivers/memory/tegra/mc.c
+++ b/drivers/memory/tegra/mc.c
@@ -735,7 +735,7 @@ static const struct dev_pm_ops tegra_mc_pm_ops = {
 	.resume = tegra_mc_resume,
 };
 
-static struct platform_driver tegra_mc_driver = {
+struct platform_driver tegra_mc_driver = {
 	.driver = {
 		.name = "tegra-mc",
 		.of_match_table = tegra_mc_of_match,
diff --git a/include/soc/tegra/mc.h b/include/soc/tegra/mc.h
index 1238e35653d1..49a4cf64c4b9 100644
--- a/include/soc/tegra/mc.h
+++ b/include/soc/tegra/mc.h
@@ -184,4 +184,6 @@ struct tegra_mc {
 int tegra_mc_write_emem_configuration(struct tegra_mc *mc, unsigned long rate);
 unsigned int tegra_mc_get_emem_device_count(struct tegra_mc *mc);
 
+extern struct platform_driver tegra_mc_driver;
+
 #endif /* __SOC_TEGRA_MC_H__ */
-- 
2.17.1

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Re: [PATCH 3/5] iommu/tegra-smmu: Use iommu_fwspec in .probe_/.attach_device()

[Dmitry Osipenko]

26.09.2020 11:07, Nicolin Chen пишет:
...
> +	/* NULL smmu pointer means that SMMU driver is not probed yet */
> +	if (unlikely(!smmu))
> +		return ERR_PTR(-EPROBE_DEFER);

Hello, Nicolin!

Please don't pollute code with likely/unlikely. This is not a
performance-critical code.

...
> -static struct platform_driver tegra_mc_driver = {
> +struct platform_driver tegra_mc_driver = {
>  	.driver = {
>  		.name = "tegra-mc",
>  		.of_match_table = tegra_mc_of_match,
> diff --git a/include/soc/tegra/mc.h b/include/soc/tegra/mc.h
> index 1238e35653d1..49a4cf64c4b9 100644
> --- a/include/soc/tegra/mc.h
> +++ b/include/soc/tegra/mc.h
> @@ -184,4 +184,6 @@ struct tegra_mc {
>  int tegra_mc_write_emem_configuration(struct tegra_mc *mc, unsigned long rate);
>  unsigned int tegra_mc_get_emem_device_count(struct tegra_mc *mc);
>  
> +extern struct platform_driver tegra_mc_driver;

No global variables, please. See for the example:

https://elixir.bootlin.com/linux/v5.9-rc6/source/drivers/devfreq/tegra20-devfreq.c#L100

The tegra_get_memory_controller() is now needed by multiple Tegra
drivers, I think it should be good to have it added into the MC driver
and then make it globally available for all drivers by making use of
of_find_matching_node_and_match().

diff --git a/drivers/memory/tegra/mc.c b/drivers/memory/tegra/mc.c
index e1db209fd2ea..ed1bd6d00aaf 100644
--- a/drivers/memory/tegra/mc.c
+++ b/drivers/memory/tegra/mc.c
@@ -43,6 +43,29 @@ static const struct of_device_id tegra_mc_of_match[] = {
 };
 MODULE_DEVICE_TABLE(of, tegra_mc_of_match);

+struct tegra_mc *tegra_get_memory_controller(void)
+{
+	struct platform_device *pdev;
+	struct device_node *np;
+	struct tegra_mc *mc;
+
+	np = of_find_matching_node_and_match(NULL, tegra_mc_of_match, NULL);
+	if (!np)
+		return ERR_PTR(-ENOENT);
+
+	pdev = of_find_device_by_node(np);
+	of_node_put(np);
+	if (!pdev)
+		return ERR_PTR(-ENODEV);
+
+	mc = platform_get_drvdata(pdev);
+	if (!mc)
+		return ERR_PTR(-EPROBE_DEFER);
+
+	return mc;
+}
+EXPORT_SYMBOL_GPL(tegra_get_memory_controller);
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Re: [PATCH 3/5] iommu/tegra-smmu: Use iommu_fwspec in .probe_/.attach_device()

[Nicolin Chen]

Hi Dmitry,

Thank you for the review and comments!

On Sat, Sep 26, 2020 at 05:48:17PM +0300, Dmitry Osipenko wrote:
> 26.09.2020 11:07, Nicolin Chen пишет:
> ...
> > +	/* NULL smmu pointer means that SMMU driver is not probed yet */
> > +	if (unlikely(!smmu))
> > +		return ERR_PTR(-EPROBE_DEFER);
> 
> Hello, Nicolin!
> 
> Please don't pollute code with likely/unlikely. This is not a
> performance-critical code.

Will drop it. Thanks.

> ...
> > -static struct platform_driver tegra_mc_driver = {
> > +struct platform_driver tegra_mc_driver = {
> >  	.driver = {
> >  		.name = "tegra-mc",
> >  		.of_match_table = tegra_mc_of_match,
> > diff --git a/include/soc/tegra/mc.h b/include/soc/tegra/mc.h
> > index 1238e35653d1..49a4cf64c4b9 100644
> > --- a/include/soc/tegra/mc.h
> > +++ b/include/soc/tegra/mc.h
> > @@ -184,4 +184,6 @@ struct tegra_mc {
> >  int tegra_mc_write_emem_configuration(struct tegra_mc *mc, unsigned long rate);
> >  unsigned int tegra_mc_get_emem_device_count(struct tegra_mc *mc);
> >  
> > +extern struct platform_driver tegra_mc_driver;
> 
> No global variables, please. See for the example:
> 
> https://elixir.bootlin.com/linux/v5.9-rc6/source/drivers/devfreq/tegra20-devfreq.c#L100

Will fix it. Thanks for the example.

> 
> The tegra_get_memory_controller() is now needed by multiple Tegra
> drivers, I think it should be good to have it added into the MC driver
> and then make it globally available for all drivers by making use of
> of_find_matching_node_and_match().
> 
> diff --git a/drivers/memory/tegra/mc.c b/drivers/memory/tegra/mc.c
> index e1db209fd2ea..ed1bd6d00aaf 100644
> --- a/drivers/memory/tegra/mc.c
> +++ b/drivers/memory/tegra/mc.c
> @@ -43,6 +43,29 @@ static const struct of_device_id tegra_mc_of_match[] = {
>  };
>  MODULE_DEVICE_TABLE(of, tegra_mc_of_match);
> 
> +struct tegra_mc *tegra_get_memory_controller(void)
> +{
> +	struct platform_device *pdev;
> +	struct device_node *np;
> +	struct tegra_mc *mc;
> +
> +	np = of_find_matching_node_and_match(NULL, tegra_mc_of_match, NULL);
> +	if (!np)
> +		return ERR_PTR(-ENOENT);
> +
> +	pdev = of_find_device_by_node(np);
> +	of_node_put(np);
> +	if (!pdev)
> +		return ERR_PTR(-ENODEV);
> +
> +	mc = platform_get_drvdata(pdev);
> +	if (!mc)
> +		return ERR_PTR(-EPROBE_DEFER);
> +
> +	return mc;
> +}
> +EXPORT_SYMBOL_GPL(tegra_get_memory_controller);

Will try this one and integrate into my next version.

Thanks
Nic
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Re: [PATCH 3/5] iommu/tegra-smmu: Use iommu_fwspec in .probe_/.attach_device()

[Thierry Reding]

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On Sat, Sep 26, 2020 at 05:48:17PM +0300, Dmitry Osipenko wrote:
> 26.09.2020 11:07, Nicolin Chen пишет:
> ...
> > +	/* NULL smmu pointer means that SMMU driver is not probed yet */
> > +	if (unlikely(!smmu))
> > +		return ERR_PTR(-EPROBE_DEFER);
> 
> Hello, Nicolin!
> 
> Please don't pollute code with likely/unlikely. This is not a
> performance-critical code.
> 
> ...
> > -static struct platform_driver tegra_mc_driver = {
> > +struct platform_driver tegra_mc_driver = {
> >  	.driver = {
> >  		.name = "tegra-mc",
> >  		.of_match_table = tegra_mc_of_match,
> > diff --git a/include/soc/tegra/mc.h b/include/soc/tegra/mc.h
> > index 1238e35653d1..49a4cf64c4b9 100644
> > --- a/include/soc/tegra/mc.h
> > +++ b/include/soc/tegra/mc.h
> > @@ -184,4 +184,6 @@ struct tegra_mc {
> >  int tegra_mc_write_emem_configuration(struct tegra_mc *mc, unsigned long rate);
> >  unsigned int tegra_mc_get_emem_device_count(struct tegra_mc *mc);
> >  
> > +extern struct platform_driver tegra_mc_driver;
> 
> No global variables, please. See for the example:
> 
> https://elixir.bootlin.com/linux/v5.9-rc6/source/drivers/devfreq/tegra20-devfreq.c#L100
> 
> The tegra_get_memory_controller() is now needed by multiple Tegra
> drivers, I think it should be good to have it added into the MC driver
> and then make it globally available for all drivers by making use of
> of_find_matching_node_and_match().
> 
> diff --git a/drivers/memory/tegra/mc.c b/drivers/memory/tegra/mc.c
> index e1db209fd2ea..ed1bd6d00aaf 100644
> --- a/drivers/memory/tegra/mc.c
> +++ b/drivers/memory/tegra/mc.c
> @@ -43,6 +43,29 @@ static const struct of_device_id tegra_mc_of_match[] = {
>  };
>  MODULE_DEVICE_TABLE(of, tegra_mc_of_match);
> 
> +struct tegra_mc *tegra_get_memory_controller(void)
> +{
> +	struct platform_device *pdev;
> +	struct device_node *np;
> +	struct tegra_mc *mc;
> +
> +	np = of_find_matching_node_and_match(NULL, tegra_mc_of_match, NULL);
> +	if (!np)
> +		return ERR_PTR(-ENOENT);
> +
> +	pdev = of_find_device_by_node(np);
> +	of_node_put(np);
> +	if (!pdev)
> +		return ERR_PTR(-ENODEV);
> +
> +	mc = platform_get_drvdata(pdev);
> +	if (!mc)
> +		return ERR_PTR(-EPROBE_DEFER);
> +
> +	return mc;
> +}
> +EXPORT_SYMBOL_GPL(tegra_get_memory_controller);

We already have tegra_smmu_find(), which should be enough for this
particular use-case.

Thierry

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Re: [PATCH 3/5] iommu/tegra-smmu: Use iommu_fwspec in .probe_/.attach_device()

[Thierry Reding]

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On Sat, Sep 26, 2020 at 01:07:17AM -0700, Nicolin Chen wrote:
> The tegra_smmu_probe_device() function searches in DT for the iommu
> phandler to get "smmu" pointer. This works for most of SMMU clients
> that exist in the DTB. But a PCI device will not be added to iommu,
> since it doesn't have a DT node.
> 
> Fortunately, for a client with a DT node, tegra_smmu_probe_device()
> calls tegra_smmu_of_xlate() via tegra_smmu_configure(), while for a
> PCI device, of_pci_iommu_init() in the IOMMU core calls .of_xlate()
> as well, even before running tegra_smmu_probe_device(). And in both
> cases, tegra_smmu_of_xlate() prepares a valid iommu_fwspec pointer
> that allows us to get the mc->smmu pointer via dev_get_drvdata() by
> calling driver_find_device_by_fwnode().
> 
> So this patch uses iommu_fwspec in .probe_device() and related code
> for a client that does not exist in the DTB, especially a PCI one.
> 
> Signed-off-by: Nicolin Chen <nicoleotsuka@gmail.com>
> ---
>  drivers/iommu/tegra-smmu.c | 89 +++++++++++++++++++++++---------------
>  drivers/memory/tegra/mc.c  |  2 +-
>  include/soc/tegra/mc.h     |  2 +
>  3 files changed, 56 insertions(+), 37 deletions(-)
> 
> diff --git a/drivers/iommu/tegra-smmu.c b/drivers/iommu/tegra-smmu.c
> index b10e02073610..97a7185b4578 100644
> --- a/drivers/iommu/tegra-smmu.c
> +++ b/drivers/iommu/tegra-smmu.c
> @@ -13,6 +13,7 @@
>  #include <linux/platform_device.h>
>  #include <linux/slab.h>
>  #include <linux/spinlock.h>
> +#include <linux/dma-iommu.h>

Why is this needed? I don't see any of the symbols declared in that file
used here.

>  #include <linux/dma-mapping.h>
>  
>  #include <soc/tegra/ahb.h>
> @@ -61,6 +62,8 @@ struct tegra_smmu_as {
>  	u32 attr;
>  };
>  
> +static const struct iommu_ops tegra_smmu_ops;
> +
>  static struct tegra_smmu_as *to_smmu_as(struct iommu_domain *dom)
>  {
>  	return container_of(dom, struct tegra_smmu_as, domain);
> @@ -484,60 +487,49 @@ static void tegra_smmu_as_unprepare(struct tegra_smmu *smmu,
>  static int tegra_smmu_attach_dev(struct iommu_domain *domain,
>  				 struct device *dev)
>  {
> +	struct iommu_fwspec *fwspec = dev_iommu_fwspec_get(dev);
>  	struct tegra_smmu *smmu = dev_iommu_priv_get(dev);
>  	struct tegra_smmu_as *as = to_smmu_as(domain);
> -	struct device_node *np = dev->of_node;
> -	struct of_phandle_args args;
> -	unsigned int index = 0;
> -	int err = 0;
> -
> -	while (!of_parse_phandle_with_args(np, "iommus", "#iommu-cells", index,
> -					   &args)) {
> -		unsigned int swgroup = args.args[0];
> -
> -		if (args.np != smmu->dev->of_node) {
> -			of_node_put(args.np);
> -			continue;
> -		}
> +	int index, err = 0;
>  
> -		of_node_put(args.np);
> +	if (!fwspec || fwspec->ops != &tegra_smmu_ops)
> +		return -ENOENT;
>  
> +	for (index = 0; index < fwspec->num_ids; index++) {
>  		err = tegra_smmu_as_prepare(smmu, as);
> -		if (err < 0)
> -			return err;
> +		if (err)
> +			goto err_disable;

I'd personally drop the err_ prefix here because it's pretty obvious
that we're going to do this as a result of an error happening.

>  
> -		tegra_smmu_enable(smmu, swgroup, as->id);
> -		index++;
> +		tegra_smmu_enable(smmu, fwspec->ids[index], as->id);
>  	}
>  
>  	if (index == 0)
>  		return -ENODEV;
>  
>  	return 0;
> +
> +err_disable:
> +	for (index--; index >= 0; index--) {
> +		tegra_smmu_disable(smmu, fwspec->ids[index], as->id);
> +		tegra_smmu_as_unprepare(smmu, as);
> +	}

I think a more idiomatic version of doing this would be:

	while (index--) {
		...
	}

> +
> +	return err;
>  }
>  
>  static void tegra_smmu_detach_dev(struct iommu_domain *domain, struct device *dev)
>  {
> +	struct iommu_fwspec *fwspec = dev_iommu_fwspec_get(dev);
>  	struct tegra_smmu_as *as = to_smmu_as(domain);
> -	struct device_node *np = dev->of_node;
>  	struct tegra_smmu *smmu = as->smmu;
> -	struct of_phandle_args args;
>  	unsigned int index = 0;
>  
> -	while (!of_parse_phandle_with_args(np, "iommus", "#iommu-cells", index,
> -					   &args)) {
> -		unsigned int swgroup = args.args[0];
> -
> -		if (args.np != smmu->dev->of_node) {
> -			of_node_put(args.np);
> -			continue;
> -		}
> -
> -		of_node_put(args.np);
> +	if (!fwspec || fwspec->ops != &tegra_smmu_ops)
> +		return;
>  
> -		tegra_smmu_disable(smmu, swgroup, as->id);
> +	for (index = 0; index < fwspec->num_ids; index++) {
> +		tegra_smmu_disable(smmu, fwspec->ids[index], as->id);
>  		tegra_smmu_as_unprepare(smmu, as);
> -		index++;
>  	}
>  }
>  
> @@ -845,10 +837,25 @@ static int tegra_smmu_configure(struct tegra_smmu *smmu, struct device *dev,
>  	return 0;
>  }
>  
> +static struct tegra_smmu *tegra_smmu_get_by_fwnode(struct fwnode_handle *fwnode)
> +{
> +	struct device *dev = driver_find_device_by_fwnode(&tegra_mc_driver.driver, fwnode);
> +	struct tegra_mc *mc;
> +
> +	if (!dev)
> +		return NULL;
> +
> +	put_device(dev);
> +	mc = dev_get_drvdata(dev);
> +
> +	return mc->smmu;
> +}
> +

As I mentioned in another reply, I think tegra_smmu_find() should be all
you need in this case.

>  static struct iommu_device *tegra_smmu_probe_device(struct device *dev)
>  {
>  	struct device_node *np = dev->of_node;
>  	struct tegra_smmu *smmu = NULL;
> +	struct iommu_fwspec *fwspec;
>  	struct of_phandle_args args;
>  	unsigned int index = 0;
>  	int err;
> @@ -868,8 +875,6 @@ static struct iommu_device *tegra_smmu_probe_device(struct device *dev)
>  			 * supported by the Linux kernel, so abort after the
>  			 * first match.
>  			 */
> -			dev_iommu_priv_set(dev, smmu);
> -
>  			break;
>  		}
>  
> @@ -877,8 +882,20 @@ static struct iommu_device *tegra_smmu_probe_device(struct device *dev)
>  		index++;
>  	}
>  
> -	if (!smmu)
> -		return ERR_PTR(-ENODEV);
> +	/* Any device should be able to get smmu pointer using fwspec */
> +	if (!smmu) {
> +		fwspec = dev_iommu_fwspec_get(dev);
> +		if (!fwspec || fwspec->ops != &tegra_smmu_ops)
> +			return ERR_PTR(-ENODEV);
> +
> +		smmu = tegra_smmu_get_by_fwnode(fwspec->iommu_fwnode);
> +	}
> +
> +	/* NULL smmu pointer means that SMMU driver is not probed yet */
> +	if (unlikely(!smmu))
> +		return ERR_PTR(-EPROBE_DEFER);
> +
> +	dev_iommu_priv_set(dev, smmu);

Can this not be unified with the OF code above? Basically in all cases
where we use Tegra SMMU, a fwnode_node should correspond 1:1 to a struct
device_node, which makes the code you added here effectively the same as
what's already there.

Thierry

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Re: [PATCH 3/5] iommu/tegra-smmu: Use iommu_fwspec in .probe_/.attach_device()

[Nicolin Chen]

On Mon, Sep 28, 2020 at 09:52:12AM +0200, Thierry Reding wrote:
> On Sat, Sep 26, 2020 at 01:07:17AM -0700, Nicolin Chen wrote:
> > @@ -13,6 +13,7 @@
> >  #include <linux/platform_device.h>
> >  #include <linux/slab.h>
> >  #include <linux/spinlock.h>
> > +#include <linux/dma-iommu.h>
> 
> Why is this needed? I don't see any of the symbols declared in that file
> used here.

Hmm..I think I mixed with some other change that needs this header
file. Removing it....

> >  #include <linux/dma-mapping.h>
> >  
> >  #include <soc/tegra/ahb.h>
> > @@ -61,6 +62,8 @@ struct tegra_smmu_as {
> >  	u32 attr;
> >  };
> >  
> > +static const struct iommu_ops tegra_smmu_ops;
> > +
> >  static struct tegra_smmu_as *to_smmu_as(struct iommu_domain *dom)
> >  {
> >  	return container_of(dom, struct tegra_smmu_as, domain);
> > @@ -484,60 +487,49 @@ static void tegra_smmu_as_unprepare(struct tegra_smmu *smmu,
> >  static int tegra_smmu_attach_dev(struct iommu_domain *domain,
> >  				 struct device *dev)
> >  {
> > +	struct iommu_fwspec *fwspec = dev_iommu_fwspec_get(dev);
> >  	struct tegra_smmu *smmu = dev_iommu_priv_get(dev);
> >  	struct tegra_smmu_as *as = to_smmu_as(domain);
> > -	struct device_node *np = dev->of_node;
> > -	struct of_phandle_args args;
> > -	unsigned int index = 0;
> > -	int err = 0;
> > -
> > -	while (!of_parse_phandle_with_args(np, "iommus", "#iommu-cells", index,
> > -					   &args)) {
> > -		unsigned int swgroup = args.args[0];
> > -
> > -		if (args.np != smmu->dev->of_node) {
> > -			of_node_put(args.np);
> > -			continue;
> > -		}
> > +	int index, err = 0;
> >  
> > -		of_node_put(args.np);
> > +	if (!fwspec || fwspec->ops != &tegra_smmu_ops)
> > +		return -ENOENT;
> >  
> > +	for (index = 0; index < fwspec->num_ids; index++) {
> >  		err = tegra_smmu_as_prepare(smmu, as);
> > -		if (err < 0)
> > -			return err;
> > +		if (err)
> > +			goto err_disable;
> 
> I'd personally drop the err_ prefix here because it's pretty obvious
> that we're going to do this as a result of an error happening.

Changing to "goto disable".

> > @@ -845,10 +837,25 @@ static int tegra_smmu_configure(struct tegra_smmu *smmu, struct device *dev,
> >  	return 0;
> >  }
> >  
> > +static struct tegra_smmu *tegra_smmu_get_by_fwnode(struct fwnode_handle *fwnode)
> > +{
> > +	struct device *dev = driver_find_device_by_fwnode(&tegra_mc_driver.driver, fwnode);
> > +	struct tegra_mc *mc;
> > +
> > +	if (!dev)
> > +		return NULL;
> > +
> > +	put_device(dev);
> > +	mc = dev_get_drvdata(dev);
> > +
> > +	return mc->smmu;
> > +}
> > +
> 
> As I mentioned in another reply, I think tegra_smmu_find() should be all
> you need in this case.

This function is used by .probe_device() where its dev pointer is
an SMMU client. IIUC, tegra_smmu_find() needs np pointer of "mc".
For a PCI device that doesn't have a DT node with iommus property,
not sure how we can use tegra_smmu_find().
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Re: [PATCH 3/5] iommu/tegra-smmu: Use iommu_fwspec in .probe_/.attach_device()

[Dmitry Osipenko]

...
>> As I mentioned in another reply, I think tegra_smmu_find() should be all
>> you need in this case.
> 
> This function is used by .probe_device() where its dev pointer is
> an SMMU client. IIUC, tegra_smmu_find() needs np pointer of "mc".
> For a PCI device that doesn't have a DT node with iommus property,
> not sure how we can use tegra_smmu_find().

Perhaps you could get np from struct pci_dev.bus?
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Re: [PATCH 3/5] iommu/tegra-smmu: Use iommu_fwspec in .probe_/.attach_device()

[Nicolin Chen]

On Tue, Sep 29, 2020 at 07:06:37AM +0300, Dmitry Osipenko wrote:
> ...
> >> As I mentioned in another reply, I think tegra_smmu_find() should be all
> >> you need in this case.
> > 
> > This function is used by .probe_device() where its dev pointer is
> > an SMMU client. IIUC, tegra_smmu_find() needs np pointer of "mc".
> > For a PCI device that doesn't have a DT node with iommus property,
> > not sure how we can use tegra_smmu_find().
> 
> Perhaps you could get np from struct pci_dev.bus?

Possibly yes...but I was hoping the solution would be potentially
reused by other devices that don't have DT nodes, USB for example,
though I haven't tested with current version.
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[PATCH 4/5] iommu/tegra-smmu: Add PCI support

[Nicolin Chen]

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);
+		}
+	}
+#endif
+
 	if (IS_ENABLED(CONFIG_DEBUG_FS))
 		tegra_smmu_debugfs_init(smmu);
 
-- 
2.17.1

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

[Dmitry Osipenko]

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);
>  
> 

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

[Nicolin Chen]

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

[Thierry Reding]

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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

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

[Nicolin Chen]

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.
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[PATCH 5/5] iommu/tegra-smmu: Add pagetable mappings to debugfs

[Nicolin Chen]

This patch dumps all active mapping entries from pagetable
to a debugfs directory named "mappings".

Ataching an example:

SWGROUP: hc
ASID: 0
reg: 0x250
PTB_ASID: 0xe00bb880
as->pd_dma: 0xbb880000
{
        [1023] 0xf00bb882 (1)
        {
                PDE   ATTR         PHYS         IOVA
                #1023 0x5    0x159f5d000    0xfffff000
        }
}
Total PDE count: 1
Total PTE count: 1

Signed-off-by: Nicolin Chen <nicoleotsuka@gmail.com>
---
 drivers/iommu/tegra-smmu.c | 130 +++++++++++++++++++++++++++++++++++--
 1 file changed, 125 insertions(+), 5 deletions(-)

diff --git a/drivers/iommu/tegra-smmu.c b/drivers/iommu/tegra-smmu.c
index 9dbc5d7183cc..53160d1ca086 100644
--- a/drivers/iommu/tegra-smmu.c
+++ b/drivers/iommu/tegra-smmu.c
@@ -20,6 +20,11 @@
 #include <soc/tegra/ahb.h>
 #include <soc/tegra/mc.h>
 
+struct tegra_smmu_group_debug {
+	const struct tegra_smmu_swgroup *group;
+	void *priv;
+};
+
 struct tegra_smmu_group {
 	struct list_head list;
 	struct tegra_smmu *smmu;
@@ -48,6 +53,8 @@ struct tegra_smmu {
 	struct dentry *debugfs;
 
 	struct iommu_device iommu;	/* IOMMU Core code handle */
+
+	struct tegra_smmu_group_debug *group_debug;
 };
 
 struct tegra_smmu_as {
@@ -155,6 +162,9 @@ static inline u32 smmu_readl(struct tegra_smmu *smmu, unsigned long offset)
 
 #define SMMU_PDE_ATTR		(SMMU_PDE_READABLE | SMMU_PDE_WRITABLE | \
 				 SMMU_PDE_NONSECURE)
+#define SMMU_PTE_ATTR		(SMMU_PTE_READABLE | SMMU_PTE_WRITABLE | \
+				 SMMU_PTE_NONSECURE)
+#define SMMU_PTE_ATTR_SHIFT	(29)
 
 static unsigned int iova_pd_index(unsigned long iova)
 {
@@ -337,7 +347,7 @@ static void tegra_smmu_domain_free(struct iommu_domain *domain)
 }
 
 static const struct tegra_smmu_swgroup *
-tegra_smmu_find_swgroup(struct tegra_smmu *smmu, unsigned int swgroup)
+tegra_smmu_find_swgroup(struct tegra_smmu *smmu, unsigned int swgroup, int *index)
 {
 	const struct tegra_smmu_swgroup *group = NULL;
 	unsigned int i;
@@ -345,6 +355,8 @@ tegra_smmu_find_swgroup(struct tegra_smmu *smmu, unsigned int swgroup)
 	for (i = 0; i < smmu->soc->num_swgroups; i++) {
 		if (smmu->soc->swgroups[i].swgroup == swgroup) {
 			group = &smmu->soc->swgroups[i];
+			if (index)
+				*index = i;
 			break;
 		}
 	}
@@ -353,19 +365,22 @@ tegra_smmu_find_swgroup(struct tegra_smmu *smmu, unsigned int swgroup)
 }
 
 static void tegra_smmu_enable(struct tegra_smmu *smmu, unsigned int swgroup,
-			      unsigned int asid)
+			      struct tegra_smmu_as *as)
 {
 	const struct tegra_smmu_swgroup *group;
+	unsigned int asid = as->id;
 	unsigned int i;
 	u32 value;
 
-	group = tegra_smmu_find_swgroup(smmu, swgroup);
+	group = tegra_smmu_find_swgroup(smmu, swgroup, &i);
 	if (group) {
 		value = smmu_readl(smmu, group->reg);
 		value &= ~SMMU_ASID_MASK;
 		value |= SMMU_ASID_VALUE(asid);
 		value |= SMMU_ASID_ENABLE;
 		smmu_writel(smmu, value, group->reg);
+		if (smmu->group_debug)
+			smmu->group_debug[i].priv = as;
 	} else {
 		pr_warn("%s group from swgroup %u not found\n", __func__,
 				swgroup);
@@ -392,13 +407,15 @@ static void tegra_smmu_disable(struct tegra_smmu *smmu, unsigned int swgroup,
 	unsigned int i;
 	u32 value;
 
-	group = tegra_smmu_find_swgroup(smmu, swgroup);
+	group = tegra_smmu_find_swgroup(smmu, swgroup, &i);
 	if (group) {
 		value = smmu_readl(smmu, group->reg);
 		value &= ~SMMU_ASID_MASK;
 		value |= SMMU_ASID_VALUE(asid);
 		value &= ~SMMU_ASID_ENABLE;
 		smmu_writel(smmu, value, group->reg);
+		if (smmu->group_debug)
+			smmu->group_debug[i].priv = NULL;
 	}
 
 	for (i = 0; i < smmu->soc->num_clients; i++) {
@@ -501,7 +518,7 @@ static int tegra_smmu_attach_dev(struct iommu_domain *domain,
 		if (err)
 			goto err_disable;
 
-		tegra_smmu_enable(smmu, fwspec->ids[index], as->id);
+		tegra_smmu_enable(smmu, fwspec->ids[index], as);
 	}
 
 	if (index == 0)
@@ -1078,8 +1095,96 @@ static int tegra_smmu_clients_show(struct seq_file *s, void *data)
 
 DEFINE_SHOW_ATTRIBUTE(tegra_smmu_clients);
 
+static int tegra_smmu_mappings_show(struct seq_file *s, void *data)
+{
+	struct tegra_smmu_group_debug *group_debug = s->private;
+	const struct tegra_smmu_swgroup *group;
+	struct tegra_smmu_as *as;
+	struct tegra_smmu *smmu;
+	int pd_index, pt_index;
+	u64 pte_count = 0;
+	u32 pde_count = 0;
+	u32 val, ptb_reg;
+	u32 *pd;
+
+	if (!group_debug || !group_debug->priv || !group_debug->group)
+		return 0;
+
+	group = group_debug->group;
+	as = group_debug->priv;
+	smmu = as->smmu;
+
+	val = smmu_readl(smmu, group->reg) & SMMU_ASID_ENABLE;
+	if (!val)
+		return 0;
+
+	pd = page_address(as->pd);
+	if (!pd)
+		return 0;
+
+	seq_printf(s, "\nSWGROUP: %s\nASID: %d\nreg: 0x%x\n", group->name,
+			as->id, group->reg);
+
+	mutex_lock(&smmu->lock);
+	smmu_writel(smmu, as->id & 0x7f, SMMU_PTB_ASID);
+	ptb_reg = smmu_readl(smmu, SMMU_PTB_DATA);
+	mutex_unlock(&smmu->lock);
+
+	seq_printf(s, "PTB_ASID: 0x%x\nas->pd_dma: 0x%llx\n", ptb_reg, as->pd_dma);
+	seq_puts(s, "{\n");
+
+	for (pd_index = 0; pd_index < SMMU_NUM_PDE; pd_index++) {
+		struct page *pt;
+		u32 *addr;
+
+		if (!as->count[pd_index] || !pd[pd_index])
+			continue;
+
+		pde_count++;
+		pte_count += as->count[pd_index];
+		seq_printf(s, "\t[%d] 0x%x (%d)\n",
+			   pd_index, pd[pd_index], as->count[pd_index]);
+		pt = as->pts[pd_index];
+		addr = page_address(pt);
+
+		seq_puts(s, "\t{\n");
+		seq_printf(s, "\t\t%-5s %-4s %12s %12s\n", "PDE", "ATTR", "PHYS", "IOVA");
+		for (pt_index = 0; pt_index < SMMU_NUM_PTE; pt_index++) {
+			u64 iova;
+
+			if (!addr[pt_index])
+				continue;
+
+			iova = ((dma_addr_t)pd_index & (SMMU_NUM_PDE - 1)) << SMMU_PDE_SHIFT;
+			iova |= ((dma_addr_t)pt_index & (SMMU_NUM_PTE - 1)) << SMMU_PTE_SHIFT;
+
+			seq_printf(s, "\t\t#%-4d 0x%-4x 0x%-12llx 0x%-12llx\n",
+				   pt_index, addr[pt_index] >> SMMU_PTE_ATTR_SHIFT,
+				   SMMU_PFN_PHYS(addr[pt_index] & ~SMMU_PTE_ATTR), iova);
+		}
+		seq_puts(s, "\t}\n");
+	}
+	seq_puts(s, "}\n");
+	seq_printf(s, "Total PDE count: %d\n", pde_count);
+	seq_printf(s, "Total PTE count: %lld\n", pte_count);
+
+	return 0;
+}
+
+DEFINE_SHOW_ATTRIBUTE(tegra_smmu_mappings);
+
 static void tegra_smmu_debugfs_init(struct tegra_smmu *smmu)
 {
+	const struct tegra_smmu_soc *soc = smmu->soc;
+	struct tegra_smmu_group_debug *group_debug;
+	struct device *dev = smmu->dev;
+	struct dentry *d;
+	int i;
+
+	group_debug = devm_kzalloc(dev, sizeof(*group_debug) * soc->num_swgroups, GFP_KERNEL);
+	if (!group_debug)
+		return;
+
 	smmu->debugfs = debugfs_create_dir("smmu", NULL);
 	if (!smmu->debugfs)
 		return;
@@ -1088,6 +1193,21 @@ static void tegra_smmu_debugfs_init(struct tegra_smmu *smmu)
 			    &tegra_smmu_swgroups_fops);
 	debugfs_create_file("clients", S_IRUGO, smmu->debugfs, smmu,
 			    &tegra_smmu_clients_fops);
+	d = debugfs_create_dir("mappings", smmu->debugfs);
+
+	for (i = 0; i < soc->num_swgroups; i++) {
+		const struct tegra_smmu_swgroup *group = &soc->swgroups[i];
+
+		if (!group->name)
+			continue;
+
+		group_debug[i].group = group;
+
+		debugfs_create_file(group->name, 0444, d, &group_debug[i],
+				    &tegra_smmu_mappings_fops);
+	}
+
+	smmu->group_debug = group_debug;
 }
 
 static void tegra_smmu_debugfs_exit(struct tegra_smmu *smmu)
-- 
2.17.1

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Re: [PATCH 5/5] iommu/tegra-smmu: Add pagetable mappings to debugfs

[Dmitry Osipenko]

26.09.2020 11:07, Nicolin Chen пишет:
...
> +static int tegra_smmu_mappings_show(struct seq_file *s, void *data)
> +{
> +	struct tegra_smmu_group_debug *group_debug = s->private;
> +	const struct tegra_smmu_swgroup *group;
> +	struct tegra_smmu_as *as;
> +	struct tegra_smmu *smmu;
> +	int pd_index, pt_index;
> +	u64 pte_count = 0;
> +	u32 pde_count = 0;
> +	u32 val, ptb_reg;
> +	u32 *pd;
> +
> +	if (!group_debug || !group_debug->priv || !group_debug->group)
> +		return 0;
> +
> +	group = group_debug->group;
> +	as = group_debug->priv;
> +	smmu = as->smmu;
> +
> +	val = smmu_readl(smmu, group->reg) & SMMU_ASID_ENABLE;
> +	if (!val)
> +		return 0;
> +
> +	pd = page_address(as->pd);
> +	if (!pd)
> +		return 0;
> +
> +	seq_printf(s, "\nSWGROUP: %s\nASID: %d\nreg: 0x%x\n", group->name,
> +			as->id, group->reg);
> +
> +	mutex_lock(&smmu->lock);
> +	smmu_writel(smmu, as->id & 0x7f, SMMU_PTB_ASID);
> +	ptb_reg = smmu_readl(smmu, SMMU_PTB_DATA);

I think the whole traverse needs a locking protection, doesn't it?

> +	mutex_unlock(&smmu->lock);
> +
> +	seq_printf(s, "PTB_ASID: 0x%x\nas->pd_dma: 0x%llx\n", ptb_reg, as->pd_dma);
> +	seq_puts(s, "{\n");
> +
> +	for (pd_index = 0; pd_index < SMMU_NUM_PDE; pd_index++) {
> +		struct page *pt;
> +		u32 *addr;
> +
> +		if (!as->count[pd_index] || !pd[pd_index])
> +			continue;
> +
> +		pde_count++;
> +		pte_count += as->count[pd_index];
> +		seq_printf(s, "\t[%d] 0x%x (%d)\n",
> +			   pd_index, pd[pd_index], as->count[pd_index]);
> +		pt = as->pts[pd_index];
> +		addr = page_address(pt);

This needs as->lock protection.

> +		seq_puts(s, "\t{\n");
> +		seq_printf(s, "\t\t%-5s %-4s %12s %12s\n", "PDE", "ATTR", "PHYS", "IOVA");
> +		for (pt_index = 0; pt_index < SMMU_NUM_PTE; pt_index++) {
> +			u64 iova;
> +
> +			if (!addr[pt_index])
> +				continue;
> +
> +			iova = ((dma_addr_t)pd_index & (SMMU_NUM_PDE - 1)) << SMMU_PDE_SHIFT;
> +			iova |= ((dma_addr_t)pt_index & (SMMU_NUM_PTE - 1)) << SMMU_PTE_SHIFT;
> +
> +			seq_printf(s, "\t\t#%-4d 0x%-4x 0x%-12llx 0x%-12llx\n",
> +				   pt_index, addr[pt_index] >> SMMU_PTE_ATTR_SHIFT,
> +				   SMMU_PFN_PHYS(addr[pt_index] & ~SMMU_PTE_ATTR), iova);
> +		}
> +		seq_puts(s, "\t}\n");
> +	}
> +	seq_puts(s, "}\n");
> +	seq_printf(s, "Total PDE count: %d\n", pde_count);
> +	seq_printf(s, "Total PTE count: %lld\n", pte_count);
> +
> +	return 0;
> +}
> +
> +DEFINE_SHOW_ATTRIBUTE(tegra_smmu_mappings);
> +
>  static void tegra_smmu_debugfs_init(struct tegra_smmu *smmu)
>  {
> +	const struct tegra_smmu_soc *soc = smmu->soc;
> +	struct tegra_smmu_group_debug *group_debug;
> +	struct device *dev = smmu->dev;
> +	struct dentry *d;
> +	int i;
> +
> +	group_debug = devm_kzalloc(dev, sizeof(*group_debug) * soc->num_swgroups, GFP_KERNEL);

devm_kcalloc()
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Re: [PATCH 5/5] iommu/tegra-smmu: Add pagetable mappings to debugfs

[Nicolin Chen]

Hi Dmitry,

Thank you for the review.

On Sat, Sep 26, 2020 at 05:48:54PM +0300, Dmitry Osipenko wrote:
> 26.09.2020 11:07, Nicolin Chen пишет:
> ...
> > +static int tegra_smmu_mappings_show(struct seq_file *s, void *data)
> > +{
> > +	struct tegra_smmu_group_debug *group_debug = s->private;
> > +	const struct tegra_smmu_swgroup *group;
> > +	struct tegra_smmu_as *as;
> > +	struct tegra_smmu *smmu;
> > +	int pd_index, pt_index;
> > +	u64 pte_count = 0;
> > +	u32 pde_count = 0;
> > +	u32 val, ptb_reg;
> > +	u32 *pd;
> > +
> > +	if (!group_debug || !group_debug->priv || !group_debug->group)
> > +		return 0;
> > +
> > +	group = group_debug->group;
> > +	as = group_debug->priv;
> > +	smmu = as->smmu;
> > +
> > +	val = smmu_readl(smmu, group->reg) & SMMU_ASID_ENABLE;
> > +	if (!val)
> > +		return 0;
> > +
> > +	pd = page_address(as->pd);
> > +	if (!pd)
> > +		return 0;
> > +
> > +	seq_printf(s, "\nSWGROUP: %s\nASID: %d\nreg: 0x%x\n", group->name,
> > +			as->id, group->reg);
> > +
> > +	mutex_lock(&smmu->lock);
> > +	smmu_writel(smmu, as->id & 0x7f, SMMU_PTB_ASID);
> > +	ptb_reg = smmu_readl(smmu, SMMU_PTB_DATA);
> 
> I think the whole traverse needs a locking protection, doesn't it?

Hmm..probably would be nicer. Will move the mutex to the top.

> > +	mutex_unlock(&smmu->lock);
> > +
> > +	seq_printf(s, "PTB_ASID: 0x%x\nas->pd_dma: 0x%llx\n", ptb_reg, as->pd_dma);
> > +	seq_puts(s, "{\n");
> > +
> > +	for (pd_index = 0; pd_index < SMMU_NUM_PDE; pd_index++) {
> > +		struct page *pt;
> > +		u32 *addr;
> > +
> > +		if (!as->count[pd_index] || !pd[pd_index])
> > +			continue;
> > +
> > +		pde_count++;
> > +		pte_count += as->count[pd_index];
> > +		seq_printf(s, "\t[%d] 0x%x (%d)\n",
> > +			   pd_index, pd[pd_index], as->count[pd_index]);
> > +		pt = as->pts[pd_index];
> > +		addr = page_address(pt);
> 
> This needs as->lock protection.

Will add that.

> > +		seq_puts(s, "\t{\n");
> > +		seq_printf(s, "\t\t%-5s %-4s %12s %12s\n", "PDE", "ATTR", "PHYS", "IOVA");
> > +		for (pt_index = 0; pt_index < SMMU_NUM_PTE; pt_index++) {
> > +			u64 iova;
> > +
> > +			if (!addr[pt_index])
> > +				continue;
> > +
> > +			iova = ((dma_addr_t)pd_index & (SMMU_NUM_PDE - 1)) << SMMU_PDE_SHIFT;
> > +			iova |= ((dma_addr_t)pt_index & (SMMU_NUM_PTE - 1)) << SMMU_PTE_SHIFT;
> > +
> > +			seq_printf(s, "\t\t#%-4d 0x%-4x 0x%-12llx 0x%-12llx\n",
> > +				   pt_index, addr[pt_index] >> SMMU_PTE_ATTR_SHIFT,
> > +				   SMMU_PFN_PHYS(addr[pt_index] & ~SMMU_PTE_ATTR), iova);
> > +		}
> > +		seq_puts(s, "\t}\n");
> > +	}
> > +	seq_puts(s, "}\n");
> > +	seq_printf(s, "Total PDE count: %d\n", pde_count);
> > +	seq_printf(s, "Total PTE count: %lld\n", pte_count);
> > +
> > +	return 0;
> > +}
> > +
> > +DEFINE_SHOW_ATTRIBUTE(tegra_smmu_mappings);
> > +
> >  static void tegra_smmu_debugfs_init(struct tegra_smmu *smmu)
> >  {
> > +	const struct tegra_smmu_soc *soc = smmu->soc;
> > +	struct tegra_smmu_group_debug *group_debug;
> > +	struct device *dev = smmu->dev;
> > +	struct dentry *d;
> > +	int i;
> > +
> > +	group_debug = devm_kzalloc(dev, sizeof(*group_debug) * soc->num_swgroups, GFP_KERNEL);
> 
> devm_kcalloc()

Will change it.

Thanks
Nic
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Re: [PATCH 5/5] iommu/tegra-smmu: Add pagetable mappings to debugfs

[Dmitry Osipenko]

26.09.2020 23:47, Nicolin Chen пишет:
...
>>> +	for (pd_index = 0; pd_index < SMMU_NUM_PDE; pd_index++) {
>>> +		struct page *pt;
>>> +		u32 *addr;
>>> +
>>> +		if (!as->count[pd_index] || !pd[pd_index])
>>> +			continue;
>>> +
>>> +		pde_count++;
>>> +		pte_count += as->count[pd_index];
>>> +		seq_printf(s, "\t[%d] 0x%x (%d)\n",
>>> +			   pd_index, pd[pd_index], as->count[pd_index]);
>>> +		pt = as->pts[pd_index];
>>> +		addr = page_address(pt);
>>
>> This needs as->lock protection.
> 
> Will add that.
> 
>>> +		seq_puts(s, "\t{\n");
>>> +		seq_printf(s, "\t\t%-5s %-4s %12s %12s\n", "PDE", "ATTR", "PHYS", "IOVA");
>>> +		for (pt_index = 0; pt_index < SMMU_NUM_PTE; pt_index++) {
>>> +			u64 iova;
>>> +
>>> +			if (!addr[pt_index])
>>> +				continue;
>>> +
>>> +			iova = ((dma_addr_t)pd_index & (SMMU_NUM_PDE - 1)) << SMMU_PDE_SHIFT;
>>> +			iova |= ((dma_addr_t)pt_index & (SMMU_NUM_PTE - 1)) << SMMU_PTE_SHIFT;
>>> +
>>> +			seq_printf(s, "\t\t#%-4d 0x%-4x 0x%-12llx 0x%-12llx\n",
>>> +				   pt_index, addr[pt_index] >> SMMU_PTE_ATTR_SHIFT,
>>> +				   SMMU_PFN_PHYS(addr[pt_index] & ~SMMU_PTE_ATTR), iova);

Please also note that the addr[pt_index] needs to be protected as well.
Perhaps you could temporally bump the as->count.
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Re: [PATCH 5/5] iommu/tegra-smmu: Add pagetable mappings to debugfs

[Dmitry Osipenko]

26.09.2020 11:07, Nicolin Chen пишет:
...
> +	for (pd_index = 0; pd_index < SMMU_NUM_PDE; pd_index++) {
> +		struct page *pt;
> +		u32 *addr;
> +
> +		if (!as->count[pd_index] || !pd[pd_index])
> +			continue;

I guess the idea of this patch is to print out the hardware state, isn't
it? Hence the as->count shouldn't be checked here.

> +		pde_count++;
> +		pte_count += as->count[pd_index];
> +		seq_printf(s, "\t[%d] 0x%x (%d)\n",
> +			   pd_index, pd[pd_index], as->count[pd_index]);
> +		pt = as->pts[pd_index];
> +		addr = page_address(pt);
> +
> +		seq_puts(s, "\t{\n");
> +		seq_printf(s, "\t\t%-5s %-4s %12s %12s\n", "PDE", "ATTR", "PHYS", "IOVA");
> +		for (pt_index = 0; pt_index < SMMU_NUM_PTE; pt_index++) {
> +			u64 iova;
> +
> +			if (!addr[pt_index])
> +				continue;
> +
> +			iova = ((dma_addr_t)pd_index & (SMMU_NUM_PDE - 1)) << SMMU_PDE_SHIFT;
> +			iova |= ((dma_addr_t)pt_index & (SMMU_NUM_PTE - 1)) << SMMU_PTE_SHIFT;
> +
> +			seq_printf(s, "\t\t#%-4d 0x%-4x 0x%-12llx 0x%-12llx\n",
> +				   pt_index, addr[pt_index] >> SMMU_PTE_ATTR_SHIFT,
> +				   SMMU_PFN_PHYS(addr[pt_index] & ~SMMU_PTE_ATTR), iova);
>

Would be nice if you could improve the output formatting by printing out
contiguous ranges that have the same ATTRs, otherwise it could be a bit
too large and unpractical output in a case if lots of pages are mapped.
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Re: [PATCH 5/5] iommu/tegra-smmu: Add pagetable mappings to debugfs

[Dmitry Osipenko]

27.09.2020 00:24, Dmitry Osipenko пишет:
> 26.09.2020 11:07, Nicolin Chen пишет:
> ...
>> +	for (pd_index = 0; pd_index < SMMU_NUM_PDE; pd_index++) {
>> +		struct page *pt;
>> +		u32 *addr;
>> +
>> +		if (!as->count[pd_index] || !pd[pd_index])
>> +			continue;
> 
> I guess the idea of this patch is to print out the hardware state, isn't
> it? Hence the as->count shouldn't be checked here.

Perhaps also will be good to check whether the state of
!as->count[pd_index] matches state of !pd[pd_index].

WARN_ON_ONCE(!as->count[pd_index] ^ !pd[pd_index])
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