[PATCH v1 07/20] iommu/qcom_iommu: Implement test_dev callbacks to domain ops

Nicolin Chen
2025-10-13T00:07:01Z

Move sanity and compatibility tests from the attach_dev callbacks to the
new test_dev callback functions. The IOMMU core makes sure an attach_dev
call must be invoked after a successful test_dev call.

Following the test_dev guideline, replace dev_err with dev_dbg.

Signed-off-by: Nicolin Chen <nicolinc@nvidia.com>
---
drivers/iommu/arm/arm-smmu/qcom_iommu.c | 46 ++++++++++++++++++-------
1 file changed, 34 insertions(+), 12 deletions(-)

diff --git a/drivers/iommu/arm/arm-smmu/qcom_iommu.c b/drivers/iommu/arm/arm-smmu/qcom_iommu.c
index 9222a4a48bb33..53b1c279563ba 100644
--- a/drivers/iommu/arm/arm-smmu/qcom_iommu.c
+++ b/drivers/iommu/arm/arm-smmu/qcom_iommu.c
@@ -359,18 +359,36 @@ static void qcom_iommu_domain_free(struct iommu_domain *domain)
kfree(qcom_domain);
}

-static int qcom_iommu_attach_dev(struct iommu_domain *domain,
- struct device *dev, struct iommu_domain *old)
+static int qcom_iommu_domain_test_dev(struct iommu_domain *domain,
+ struct device *dev, ioasid_t pasid,
+ struct iommu_domain *old)
{
struct qcom_iommu_dev *qcom_iommu = dev_iommu_priv_get(dev);
struct qcom_iommu_domain *qcom_domain = to_qcom_iommu_domain(domain);
- int ret;

if (!qcom_iommu) {
- dev_err(dev, "cannot attach to IOMMU, is it on the same bus?\n");
+ dev_dbg(dev, "cannot attach to IOMMU, is it on the same bus?\n");
return -ENXIO;
}

+ scoped_guard(mutex, &qcom_domain->init_mutex) {
+ /*
+ * Sanity check the domain. We don't support domains across
+ * different IOMMUs.
+ */
+ if (qcom_domain->iommu && qcom_domain->iommu != qcom_iommu)
+ return -EINVAL;
+ }
+
+ return 0;
+}
+
+static int qcom_iommu_attach_dev(struct iommu_domain *domain,
+ struct device *dev, struct iommu_domain *old)
+{
+ struct qcom_iommu_dev *qcom_iommu = dev_iommu_priv_get(dev);
+ int ret;
+
/* Ensure that the domain is finalized */
pm_runtime_get_sync(qcom_iommu->dev);
ret = qcom_iommu_init_domain(domain, qcom_iommu, dev);
@@ -378,13 +396,17 @@ static int qcom_iommu_attach_dev(struct iommu_domain *domain,
if (ret < 0)
return ret;

- /*
- * Sanity check the domain. We don't support domains across
- * different IOMMUs.
- */
- if (qcom_domain->iommu != qcom_iommu)
- return -EINVAL;
+ return 0;
+}

+static int qcom_iommu_identity_test(struct iommu_domain *identity_domain,
+ struct device *dev, ioasid_t pasid,
+ struct iommu_domain *old)
+{
+ if (old == identity_domain || !old)
+ return 0;
+ if (WARN_ON(!to_qcom_iommu_domain(old)->iommu))
+ return -EINVAL;
return 0;
}

@@ -401,8 +423,6 @@ static int qcom_iommu_identity_attach(struct iommu_domain *identity_domain,
return 0;

qcom_domain = to_qcom_iommu_domain(old);
- if (WARN_ON(!qcom_domain->iommu))
- return -EINVAL;

pm_runtime_get_sync(qcom_iommu->dev);
for (i = 0; i < fwspec->num_ids; i++) {
@@ -418,6 +438,7 @@ static int qcom_iommu_identity_attach(struct iommu_domain *identity_domain,
}

static struct iommu_domain_ops qcom_iommu_identity_ops = {
+ .test_dev = qcom_iommu_identity_test,
.attach_dev = qcom_iommu_identity_attach,
};

@@ -599,6 +620,7 @@ static const struct iommu_ops qcom_iommu_ops = {
.device_group = generic_device_group,
.of_xlate = qcom_iommu_of_xlate,
.default_domain_ops = &(const struct iommu_domain_ops) {
+ .test_dev = qcom_iommu_domain_test_dev,
.attach_dev = qcom_iommu_attach_dev,
.map_pages = qcom_iommu_map,
.unmap_pages = qcom_iommu_unmap,
--
2.43.0