Messages in this thread | | | Subject | Re: [PATCH v6 3/6] iommu/arm-smmu: Invoke pm_runtime during probe, add/remove device | From | Vivek Gautam <> | Date | Thu, 1 Feb 2018 18:01:54 +0530 |
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On 2/1/2018 5:03 PM, Sricharan R wrote: > Hi Robin, > > On 1/31/2018 6:36 PM, Robin Murphy wrote: >> On 19/01/18 11:43, Vivek Gautam wrote: >>> From: Sricharan R <sricharan@codeaurora.org> >>> >>> The smmu device probe/remove and add/remove master device callbacks >>> gets called when the smmu is not linked to its master, that is without >>> the context of the master device. So calling runtime apis in those places >>> separately. >>> >>> Signed-off-by: Sricharan R <sricharan@codeaurora.org> >>> [vivek: Cleanup pm runtime calls] >>> Signed-off-by: Vivek Gautam <vivek.gautam@codeaurora.org> >>> --- >>> drivers/iommu/arm-smmu.c | 45 +++++++++++++++++++++++++++++++++++++++++---- >>> 1 file changed, 41 insertions(+), 4 deletions(-) >>> >>> diff --git a/drivers/iommu/arm-smmu.c b/drivers/iommu/arm-smmu.c >>> index 21acffe91a1c..95478bfb182c 100644 >>> --- a/drivers/iommu/arm-smmu.c >>> +++ b/drivers/iommu/arm-smmu.c >>> @@ -914,11 +914,15 @@ static void arm_smmu_destroy_domain_context(struct iommu_domain *domain) >>> struct arm_smmu_domain *smmu_domain = to_smmu_domain(domain); >>> struct arm_smmu_device *smmu = smmu_domain->smmu; >>> struct arm_smmu_cfg *cfg = &smmu_domain->cfg; >>> - int irq; >>> + int ret, irq; >>> if (!smmu || domain->type == IOMMU_DOMAIN_IDENTITY) >>> return; >>> + ret = pm_runtime_get_sync(smmu->dev); >>> + if (ret) >>> + return; >>> + >>> /* >>> * Disable the context bank and free the page tables before freeing >>> * it. >>> @@ -933,6 +937,8 @@ static void arm_smmu_destroy_domain_context(struct iommu_domain *domain) >>> free_io_pgtable_ops(smmu_domain->pgtbl_ops); >>> __arm_smmu_free_bitmap(smmu->context_map, cfg->cbndx); >>> + >>> + pm_runtime_put_sync(smmu->dev); >>> } >>> static struct iommu_domain *arm_smmu_domain_alloc(unsigned type) >>> @@ -1408,12 +1414,20 @@ static int arm_smmu_add_device(struct device *dev) >>> while (i--) >>> cfg->smendx[i] = INVALID_SMENDX; >>> - ret = arm_smmu_master_alloc_smes(dev); >>> + ret = pm_runtime_get_sync(smmu->dev); >>> if (ret) >>> goto out_cfg_free; >>> + ret = arm_smmu_master_alloc_smes(dev); >>> + if (ret) { >>> + pm_runtime_put_sync(smmu->dev); >>> + goto out_cfg_free; >> Please keep to the existing pattern and put this on the cleanup path with a new label, rather than inline. > ok. > >>> + } >>> + >>> iommu_device_link(&smmu->iommu, dev); >>> + pm_runtime_put_sync(smmu->dev); >>> + >>> return 0; >>> out_cfg_free: >>> @@ -1428,7 +1442,7 @@ static void arm_smmu_remove_device(struct device *dev) >>> struct iommu_fwspec *fwspec = dev->iommu_fwspec; >>> struct arm_smmu_master_cfg *cfg; >>> struct arm_smmu_device *smmu; >>> - >>> + int ret; >>> if (!fwspec || fwspec->ops != &arm_smmu_ops) >>> return; >>> @@ -1436,8 +1450,21 @@ static void arm_smmu_remove_device(struct device *dev) >>> cfg = fwspec->iommu_priv; >>> smmu = cfg->smmu; >>> + /* >>> + * The device link between the master device and >>> + * smmu is already purged at this point. >>> + * So enable the power to smmu explicitly. >>> + */ >> I don't understand this comment, especially since we don't even introduce device links until the following patch... :/ >> > This is because the core device_del callback, does a device_links_purge for that device, > before calling the remove_device notifier. As a result, have to explicitly turn on the > power to iommu. Probably the comment should be removed, rest of the places we don't > explain why we are turning on explicitly.
Yes, will remove the comment here.
> >>> + >>> + ret = pm_runtime_get_sync(smmu->dev); >>> + if (ret) >>> + return; >>> + >>> iommu_device_unlink(&smmu->iommu, dev); >>> arm_smmu_master_free_smes(fwspec); >>> + >>> + pm_runtime_put_sync(smmu->dev); >>> + >>> iommu_group_remove_device(dev); >>> kfree(fwspec->iommu_priv); >>> iommu_fwspec_free(dev); >>> @@ -2130,6 +2157,14 @@ static int arm_smmu_device_probe(struct platform_device *pdev) >>> if (err) >>> return err; >>> + platform_set_drvdata(pdev, smmu); >>> + >>> + pm_runtime_enable(dev); >>> + >>> + err = pm_runtime_get_sync(dev); >>> + if (err) >>> + return err; >>> + >>> err = arm_smmu_device_cfg_probe(smmu); >>> if (err) >>> return err; >>> @@ -2171,9 +2206,9 @@ static int arm_smmu_device_probe(struct platform_device *pdev) >>> return err; >>> } >>> - platform_set_drvdata(pdev, smmu); >>> arm_smmu_device_reset(smmu); >>> arm_smmu_test_smr_masks(smmu); >>> + pm_runtime_put_sync(dev); >>> /* >>> * For ACPI and generic DT bindings, an SMMU will be probed before >>> @@ -2212,6 +2247,8 @@ static int arm_smmu_device_remove(struct platform_device *pdev) >>> /* Turn the thing off */ >>> writel(sCR0_CLIENTPD, ARM_SMMU_GR0_NS(smmu) + ARM_SMMU_GR0_sCR0); >>> + pm_runtime_force_suspend(smmu->dev); >> Why do we need this? I guess it might be a Qualcomm-ism as I don't see anyone else calling it from .remove other than a couple of other qcom_* drivers. Given that we only get here during system shutdown (or the root user intentionally pissing about with driver unbinding), it doesn't seem like a point where power saving really matters all that much. >> >> I'd also naively expect that anything this device was the last consumer off would get turned off by core code anyway once it's removed, but maybe things aren't that slick; I dunno :/ > hmm, that should not be needed. with turning of all consumers taken care by device_link code before > the supplier (iommu) remove gets called should ensure that. So the above force_suspend should > not be needed/can be removed. But one more thing is, we do touch the register in the above code. > So that should require a additional get/put sync around that writel.
Possibly we can replace the force_suspend() with a pm_runtime_disable() to complement pm_runtime_enable in the probe. I will test the scenario where we are writing the SMMU register in .remove path.
regards Vivek
> > Regards, > Sricharan >
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