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Subject[PATCH v10 4/5] iommu/arm-smmu: Add the device_link between masters and smmu
Date
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>
Signed-off-by: Vivek Gautam <vivek.gautam@codeaurora.org>
Reviewed-by: Tomasz Figa <tfiga@chromium.org>
---

Changes since v9:
- Using device_link_del_dev() to delete the device link, instead of
doing it in two steps - device_link_find() to first find the link, and
then calling device_link_del().

drivers/iommu/arm-smmu.c | 24 ++++++++++++++++++++++++
1 file changed, 24 insertions(+)

diff --git a/drivers/iommu/arm-smmu.c b/drivers/iommu/arm-smmu.c
index 56a04ae80bf3..4cf270ffd449 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 +1507,9 @@ static void arm_smmu_remove_device(struct device *dev)
cfg = fwspec->iommu_priv;
smmu = cfg->smmu;

+ if (pm_runtime_enabled(smmu->dev))
+ device_link_del_dev(dev, smmu->dev);
+
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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