[PATCH v5 4/6] iommu/arm-smmu: Add the device_link between masters and smmu

Vivek Gautam
2018-01-09T10:02:35Z

From: Sricharan R <sricharan@codeaurora.org>

Finally add the device link between the master device and
smmu, so that the smmu gets runtime enabled/disabled only when the
master needs it. This is done from add_device callback which gets
called once when the master is added to the smmu.

Signed-off-by: Sricharan R <sricharan@codeaurora.org>
---
drivers/iommu/arm-smmu.c | 11 +++++++++++
1 file changed, 11 insertions(+)

diff --git a/drivers/iommu/arm-smmu.c b/drivers/iommu/arm-smmu.c
index 95478bfb182c..33bbcfedb896 100644
--- a/drivers/iommu/arm-smmu.c
+++ b/drivers/iommu/arm-smmu.c
@@ -1367,6 +1367,7 @@ static int arm_smmu_add_device(struct device *dev)
struct arm_smmu_device *smmu;
struct arm_smmu_master_cfg *cfg;
struct iommu_fwspec *fwspec = dev->iommu_fwspec;
+ struct device_link *link;
int i, ret;

if (using_legacy_binding) {
@@ -1428,6 +1429,16 @@ static int arm_smmu_add_device(struct device *dev)

pm_runtime_put_sync(smmu->dev);

+ /*
+ * Establish the link between smmu and master, so that the
+ * smmu gets runtime enabled/disabled as per the master's
+ * needs.
+ */
+ link = device_link_add(dev, smmu->dev, DL_FLAG_PM_RUNTIME);
+ if (!link)
+ dev_warn(smmu->dev, "Unable to create device link between %s and %s\n",
+ dev_name(smmu->dev), dev_name(dev));
+
return 0;