Subject: [PATCH v8 10/12] iommu/arm-smmu-v3: Enable pm_runtime and setup devlinks

From: Pranjal Shrivastava <[email-masked]>
Date: Mon, 1 Jun 2026 21:59:07 +0000

Enable PM runtime for SMMUs having a power-domain during smmu probe.
Add a devlink between the clients and SMMU device. The absence of a
power domain effectively disables runtime power management.

Reviewed-by: Mostafa Saleh <[email-masked]>
Reviewed-by: Nicolin Chen <[email-masked]>
Signed-off-by: Pranjal Shrivastava <[email-masked]>
---
 drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.c | 10 ++++++++++
 1 file changed, 10 insertions(+)

diff --git a/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.c b/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.c
index 542de3a3173a..24a1bcc8974f 100644
--- a/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.c
+++ b/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.c
@@ -4243,6 +4243,9 @@ static struct iommu_device *arm_smmu_probe_device(struct device *dev)
 		pci_prepare_ats(to_pci_dev(dev), stu);
 	}
 
+	device_link_add(dev, smmu->dev,
+			DL_FLAG_PM_RUNTIME | DL_FLAG_AUTOREMOVE_SUPPLIER);
+
 	return &smmu->iommu;
 
 err_free_master:
@@ -5607,6 +5610,13 @@ static int arm_smmu_device_probe(struct platform_device *pdev)
 		goto err_free_sysfs;
 	}
 
+	if (dev->pm_domain) {
+		pm_runtime_set_active(dev);
+		pm_runtime_use_autosuspend(dev);
+		pm_runtime_set_autosuspend_delay(dev, RPM_AUTOSUSPEND_DELAY_MS);
+		pm_runtime_enable(dev);
+	}
+
 	return 0;
 
 err_free_sysfs:
-- 
2.54.0.1013.g208068f2d8-goog