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

[Vivek Gautam]

Hi,


On 1/31/2018 6:39 PM, Robin Murphy wrote:
> On 19/01/18 11:43, Vivek Gautam wrote:
> > From: Sricharan R <sricharan@xxxxxxxxxxxxxx>
> >
> > 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@xxxxxxxxxxxxxx>
> > ---
> > Â drivers/iommu/arm-smmu.c | 11 +++++++++++
> > Â 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)
> > ÂÂÂÂÂ struct arm_smmu_device *smmu;
> > ÂÂÂÂÂ struct arm_smmu_master_cfg *cfg;
> > ÂÂÂÂÂ struct iommu_fwspec *fwspec = dev->iommu_fwspec;
> > +ÂÂÂ struct device_link *link;
> > ÂÂÂÂÂ int i, ret;
> > Â ÂÂÂÂÂ if (using_legacy_binding) {
> > @@ -1428,6 +1429,16 @@ static int arm_smmu_add_device(struct device 
> > *dev)
> > Â ÂÂÂÂÂ pm_runtime_put_sync(smmu->dev);
> > Â +ÂÂÂ /*
> > +ÂÂÂÂ * Establish the link between smmu and master, so that the
> > +ÂÂÂÂ * smmu gets runtime enabled/disabled as per the master's
> > +ÂÂÂÂ * needs.
> > +ÂÂÂÂ */
> > +ÂÂÂ link = device_link_add(dev, smmu->dev, DL_FLAG_PM_RUNTIME);
> > +ÂÂÂ if (!link)
> > +ÂÂÂÂÂÂÂ dev_warn(smmu->dev, "Unable to create device link between %s 
> > and %s\n",
> > +ÂÂÂÂÂÂÂÂÂÂÂÂ dev_name(smmu->dev), dev_name(dev));
> > +
> > ÂÂÂÂÂ return 0;
> > Â Â out_cfg_free: