[PATCH 3/8] iommu/qcom: Check pm_runtime_resume_and_get() return in probe

[Mukesh Ojha]

The SMMU_INTR_SEL_NS register write in qcom_iommu_device_probe() uses
pm_runtime_get_sync() without checking the return value. If runtime
resume fails the subsequent writel_relaxed() would access hardware with
clocks potentially disabled.

Switch to pm_runtime_resume_and_get() which handles the usage-count
cleanup on failure, check the return value, and unwind the already
registered iommu device on error.

Signed-off-by: Mukesh Ojha <mukesh.ojha at oss.qualcomm.com>
---
 drivers/iommu/arm/arm-smmu/qcom_iommu.c | 6 +++++-
 1 file changed, 5 insertions(+), 1 deletion(-)

diff --git a/drivers/iommu/arm/arm-smmu/qcom_iommu.c b/drivers/iommu/arm/arm-smmu/qcom_iommu.c
index cb43276f4a39..4e714a8e1fac 100644
--- a/drivers/iommu/arm/arm-smmu/qcom_iommu.c
+++ b/drivers/iommu/arm/arm-smmu/qcom_iommu.c
@@ -859,13 +859,17 @@ static int qcom_iommu_device_probe(struct platform_device *pdev)
 	}
 
 	if (qcom_iommu->local_base) {
-		pm_runtime_get_sync(dev);
+		ret = pm_runtime_resume_and_get(dev);
+		if (ret)
+			goto err_iommu_unregister;
 		writel_relaxed(0xffffffff, qcom_iommu->local_base + SMMU_INTR_SEL_NS);
 		pm_runtime_put_sync(dev);
 	}
 
 	return 0;
 
+err_iommu_unregister:
+	iommu_device_unregister(&qcom_iommu->iommu);
 err_sysfs_remove:
 	iommu_device_sysfs_remove(&qcom_iommu->iommu);
 err_pm_disable:
-- 
2.53.0