Re: [PATCH v6 5/6] iommu/tegra-smmu: Attach as pointer to tegra_smmu_group

[Thierry Reding]

On Mon, Sep 13, 2021 at 06:38:57PM -0700, Nicolin Chen wrote:
> This could ease driver to access corresponding as pointer
> when having tegra_smmu_group pointer only, which can help
> new mappings debugfs nodes.
> 
> Also moving tegra_smmu_find_group_soc() upward, for using
> it in new tegra_smmu_attach_as(); and it's better to have
> all tegra_smmu_find_* functions together.
> 
> Signed-off-by: Nicolin Chen 
> ---
>  drivers/iommu/tegra-smmu.c | 94 +++---
>  1 file changed, 78 insertions(+), 16 deletions(-)

Acked-by: Thierry Reding 


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[PATCH v6 5/6] iommu/tegra-smmu: Attach as pointer to tegra_smmu_group

[Nicolin Chen]

This could ease driver to access corresponding as pointer
when having tegra_smmu_group pointer only, which can help
new mappings debugfs nodes.

Also moving tegra_smmu_find_group_soc() upward, for using
it in new tegra_smmu_attach_as(); and it's better to have
all tegra_smmu_find_* functions together.

Signed-off-by: Nicolin Chen 
---
 drivers/iommu/tegra-smmu.c | 94 +++---
 1 file changed, 78 insertions(+), 16 deletions(-)

diff --git a/drivers/iommu/tegra-smmu.c b/drivers/iommu/tegra-smmu.c
index 8fd4985ac91e..68c34a4a0ecc 100644
--- a/drivers/iommu/tegra-smmu.c
+++ b/drivers/iommu/tegra-smmu.c
@@ -24,6 +24,7 @@ struct tegra_smmu_group {
struct tegra_smmu *smmu;
const struct tegra_smmu_group_soc *group_soc;
const struct tegra_smmu_swgroup *swgrp;
+   struct tegra_smmu_as *as;
struct iommu_group *grp;
 };
 
@@ -349,6 +350,19 @@ tegra_smmu_find_swgrp(struct tegra_smmu *smmu, unsigned 
int swgroup)
return swgrp;
 }
 
+static const struct tegra_smmu_group_soc *
+tegra_smmu_find_group_soc(struct tegra_smmu *smmu, unsigned int swgroup)
+{
+   unsigned int i, j;
+
+   for (i = 0; i < smmu->soc->num_groups; i++)
+   for (j = 0; j < smmu->soc->groups[i].num_swgroups; j++)
+   if (smmu->soc->groups[i].swgroups[j] == swgroup)
+   return >soc->groups[i];
+
+   return NULL;
+}
+
 static void tegra_smmu_enable(struct tegra_smmu *smmu, unsigned int swgroup,
  unsigned int asid)
 {
@@ -482,6 +496,57 @@ static void tegra_smmu_as_unprepare(struct tegra_smmu 
*smmu,
mutex_unlock(>lock);
 }
 
+static void tegra_smmu_attach_as(struct tegra_smmu *smmu,
+struct tegra_smmu_as *as,
+unsigned int swgroup)
+{
+   const struct tegra_smmu_swgroup *swgrp;
+   struct tegra_smmu_group *group;
+
+   /* Find swgrp according to the swgroup id */
+   swgrp = tegra_smmu_find_swgrp(smmu, swgroup);
+   if (!swgrp)
+   return;
+
+   mutex_lock(>lock);
+
+   list_for_each_entry(group, >groups, list) {
+   if (group->swgrp != swgrp)
+   continue;
+   if (group->as)
+   dev_warn(smmu->dev,
+"overwriting group->as for swgroup: %s\n", 
swgrp->name);
+   group->as = as;
+   break;
+   }
+
+   mutex_unlock(>lock);
+}
+
+static void tegra_smmu_detach_as(struct tegra_smmu *smmu,
+unsigned int swgroup)
+{
+   const struct tegra_smmu_swgroup *swgrp;
+   struct tegra_smmu_group *group;
+   struct dentry *d;
+
+   /* Find swgrp according to the swgroup id */
+   swgrp = tegra_smmu_find_swgrp(smmu, swgroup);
+   if (!swgrp)
+   return;
+
+   mutex_lock(>lock);
+
+   list_for_each_entry(group, >groups, list) {
+   if (group->swgrp != swgrp)
+   continue;
+   group->as = NULL;
+   break;
+   }
+
+   mutex_unlock(>lock);
+}
+
 static int tegra_smmu_attach_dev(struct iommu_domain *domain,
 struct device *dev)
 {
@@ -495,11 +560,15 @@ static int tegra_smmu_attach_dev(struct iommu_domain 
*domain,
return -ENOENT;
 
for (index = 0; index < fwspec->num_ids; index++) {
+   unsigned int swgroup = fwspec->ids[index];
+
err = tegra_smmu_as_prepare(smmu, as);
if (err)
goto disable;
 
-   tegra_smmu_enable(smmu, fwspec->ids[index], as->id);
+   tegra_smmu_attach_as(smmu, as, swgroup);
+
+   tegra_smmu_enable(smmu, swgroup, as->id);
}
 
if (index == 0)
@@ -509,7 +578,10 @@ static int tegra_smmu_attach_dev(struct iommu_domain 
*domain,
 
 disable:
while (index--) {
-   tegra_smmu_disable(smmu, fwspec->ids[index], as->id);
+   unsigned int swgroup = fwspec->ids[index];
+
+   tegra_smmu_disable(smmu, swgroup, as->id);
+   tegra_smmu_detach_as(smmu, swgroup);
tegra_smmu_as_unprepare(smmu, as);
}
 
@@ -527,7 +599,10 @@ static void tegra_smmu_detach_dev(struct iommu_domain 
*domain, struct device *de
return;
 
for (index = 0; index < fwspec->num_ids; index++) {
-   tegra_smmu_disable(smmu, fwspec->ids[index], as->id);
+   unsigned int swgroup = fwspec->ids[index];
+
+   tegra_smmu_disable(smmu, swgroup, as->id);
+   tegra_smmu_detach_as(smmu, swgroup);
tegra_smmu_as_unprepare(smmu, as);
}
 }
@@ -869,19 +944,6 @@ static struct iommu_device *tegra_smmu_probe_device(struct 
device *dev)
 
 static void tegra_smmu_release_device(struct device *dev) {}
 
-static const struct