From: Sricharan R <sricha...@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 <sricha...@codeaurora.org>
Signed-off-by: Vivek Gautam <vivek.gau...@codeaurora.org>
Reviewed-by: Tomasz Figa <tf...@chromium.org>
---
 drivers/iommu/arm-smmu.c | 29 +++++++++++++++++++++++++++++
 1 file changed, 29 insertions(+)

diff --git a/drivers/iommu/arm-smmu.c b/drivers/iommu/arm-smmu.c
index 56a04ae80bf3..64953ff2281f 100644
--- a/drivers/iommu/arm-smmu.c
+++ b/drivers/iommu/arm-smmu.c
@@ -1460,10 +1460,31 @@ static int arm_smmu_add_device(struct device *dev)
 
        iommu_device_link(&smmu->iommu, dev);
 
+       if (pm_runtime_enabled(smmu->dev)) {
+               struct device_link *link;
+
+               /*
+                * 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 add link to the consumer %s\n",
+                                dev_name(dev));
+                       ret = -ENODEV;
+                       goto out_unlink;
+               }
+       }
+
        arm_smmu_rpm_put(smmu);
 
        return 0;
 
+out_unlink:
+       iommu_device_unlink(&smmu->iommu, dev);
+       arm_smmu_master_free_smes(fwspec);
 out_rpm_put:
        arm_smmu_rpm_put(smmu);
 out_cfg_free:
@@ -1486,6 +1507,14 @@ static void arm_smmu_remove_device(struct device *dev)
        cfg  = fwspec->iommu_priv;
        smmu = cfg->smmu;
 
+       if (pm_runtime_enabled(smmu->dev)) {
+               struct device_link *link;
+
+               link = device_link_find(dev, smmu->dev);
+               if (link)
+                       device_link_del(link);
+       }
+
        ret = arm_smmu_rpm_get(smmu);
        if (ret < 0)
                return;
-- 
QUALCOMM INDIA, on behalf of Qualcomm Innovation Center, Inc. is a member
of Code Aurora Forum, hosted by The Linux Foundation

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