Messages in this thread Patch in this message | | | Subject | Re: [PATCH v9 4/5] iommu/arm-smmu: Add the device_link between masters and smmu | From | Robin Murphy <> | Date | Wed, 14 Mar 2018 17:50:42 +0000 |
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On 13/03/18 08:55, 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. > > Signed-off-by: Sricharan R <sricharan@codeaurora.org> > Signed-off-by: Vivek Gautam <vivek.gautam@codeaurora.org> > Reviewed-by: Tomasz Figa <tfiga@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) {
FWIW, given that we don't really care about link itself, I'd be quite happy to simplify that lot down to:
if (pm_runtime_enabled(smmu_dev) && !device_link_add(dev, smmu->dev, DL_FLAG_PM_RUNTIME)) {
> + dev_warn(smmu->dev, > + "Unable to add link to the consumer %s\n", > + dev_name(dev));
(side note: since device_link_add() already prints a message on success, maybe it could print its own failure message too?)
Robin.
> + 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; >
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