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    SubjectRe: [PATCH v6 4/6] iommu/arm-smmu: Add the device_link between masters and smmu
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    Hi,


    On 1/31/2018 6:39 PM, Robin Murphy wrote:
    > On 19/01/18 11:43, Vivek Gautam wrote:
    >> 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.
    >
    > Don't we need to balance this with a device_link_del() in
    > .remove_device (like exynos-iommu does)?

    Right. Will add device_link_del() call. Thanks for pointing out.

    regards
    Vivek

    >
    > Robin.
    >
    >> 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;
    >>     out_cfg_free:
    >>

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