Hi Robin, On Wed, Mar 14, 2018 at 11:20 PM, Robin Murphy <robin.murphy@xxxxxxx> wrote: > On 13/03/18 08:55, 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. >> >> Signed-off-by: Sricharan R <sricharan@xxxxxxxxxxxxxx> >> Signed-off-by: Vivek Gautam <vivek.gautam@xxxxxxxxxxxxxx> >> Reviewed-by: Tomasz Figa <tfiga@xxxxxxxxxxxx> >> --- >> 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)) { Sure, will update this. > >> + 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?) Should we make device_link that verbose - to print failure messages at each step (there are atleast a couple where we return link as NULL), or we can let the users handle printing the message? regards Vivek > > 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; >> > -- QUALCOMM INDIA, on behalf of Qualcomm Innovation Center, Inc. is a member of Code Aurora Forum, hosted by The Linux Foundation -- To unsubscribe from this list: send the line "unsubscribe devicetree" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html