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Message-ID: <3e25955c-c6a6-9ca0-3c77-ae5c133d3c10@codeaurora.org>
Date: Tue, 20 Mar 2018 15:19:10 +0530
From: Vivek Gautam <vivek.gautam@...eaurora.org>
To: Robin Murphy <robin.murphy@....com>, joro@...tes.org,
robh+dt@...nel.org, iommu@...ts.linux-foundation.org,
devicetree@...r.kernel.org, linux-kernel@...r.kernel.org
Cc: mark.rutland@....com, will.deacon@....com, robdclark@...il.com,
tfiga@...omium.org, sricharan@...eaurora.org,
m.szyprowski@...sung.com, architt@...eaurora.org,
linux-arm-msm@...r.kernel.org
Subject: Re: [PATCH v9 3/5] iommu/arm-smmu: Invoke pm_runtime during probe,
add/remove device
Hi Robin,
On 3/14/2018 11:16 PM, Robin Murphy wrote:
> On 13/03/18 08:55, Vivek Gautam wrote:
>> From: Sricharan R <sricharan@...eaurora.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@...eaurora.org>
>> [vivek: Cleanup pm runtime calls]
>> Signed-off-by: Vivek Gautam <vivek.gautam@...eaurora.org>
>> Reviewed-by: Tomasz Figa <tfiga@...omium.org>
>> ---
>> drivers/iommu/arm-smmu.c | 95
>> ++++++++++++++++++++++++++++++++++++++++++++----
>> 1 file changed, 87 insertions(+), 8 deletions(-)
>>
>> diff --git a/drivers/iommu/arm-smmu.c b/drivers/iommu/arm-smmu.c
>> index d5873d545024..56a04ae80bf3 100644
>> --- a/drivers/iommu/arm-smmu.c
>> +++ b/drivers/iommu/arm-smmu.c
>> @@ -268,6 +268,20 @@ static struct arm_smmu_option_prop
>> arm_smmu_options[] = {
>> { 0, NULL},
>> };
>> +static inline int arm_smmu_rpm_get(struct arm_smmu_device *smmu)
>> +{
>> + if (pm_runtime_enabled(smmu->dev))
>> + return pm_runtime_get_sync(smmu->dev);
>> +
>> + return 0;
>> +}
>> +
>> +static inline void arm_smmu_rpm_put(struct arm_smmu_device *smmu)
>> +{
>> + if (pm_runtime_enabled(smmu->dev))
>> + pm_runtime_put(smmu->dev);
>> +}
>> +
>> static struct arm_smmu_domain *to_smmu_domain(struct iommu_domain
>> *dom)
>> {
>> return container_of(dom, struct arm_smmu_domain, domain);
>> @@ -913,11 +927,15 @@ 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 = arm_smmu_rpm_get(smmu);
>> + if (ret < 0)
>> + return;
>> +
>> /*
>> * Disable the context bank and free the page tables before
>> freeing
>> * it.
>> @@ -932,6 +950,8 @@ 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);
>> +
>> + arm_smmu_rpm_put(smmu);
>> }
>> static struct iommu_domain *arm_smmu_domain_alloc(unsigned type)
>> @@ -1213,10 +1233,15 @@ static int arm_smmu_attach_dev(struct
>> iommu_domain *domain, struct device *dev)
>> return -ENODEV;
>> smmu = fwspec_smmu(fwspec);
>> +
>> + ret = arm_smmu_rpm_get(smmu);
>> + if (ret < 0)
>> + return ret;
>> +
>> /* Ensure that the domain is finalised */
>> ret = arm_smmu_init_domain_context(domain, smmu);
>> if (ret < 0)
>> - return ret;
>> + goto rpm_put;
>> /*
>> * Sanity check the domain. We don't support domains across
>> @@ -1230,29 +1255,47 @@ static int arm_smmu_attach_dev(struct
>> iommu_domain *domain, struct device *dev)
>> }
>> /* Looks ok, so add the device to the domain */
>> - return arm_smmu_domain_add_master(smmu_domain, fwspec);
>> + ret = arm_smmu_domain_add_master(smmu_domain, fwspec);
>> +
>> +rpm_put:
>> + arm_smmu_rpm_put(smmu);
>> + return ret;
>> }
>> static int arm_smmu_map(struct iommu_domain *domain, unsigned
>> long iova,
>> phys_addr_t paddr, size_t size, int prot)
>> {
>> struct io_pgtable_ops *ops = to_smmu_domain(domain)->pgtbl_ops;
>> + struct arm_smmu_domain *smmu_domain = to_smmu_domain(domain);
>> + struct arm_smmu_device *smmu = smmu_domain->smmu;
>
> Nit: please use arm_smmu_domain for ops as well (as it was before
> 523d7423e21b), or consistently elide it for smmu - the mixture of both
> methods is just a horrible mess (here and in unmap).
Sure, will make it consistent for arm_smmu_device (in both places -
map/unmap)
struct arm_smmu_device *smmu = to_smmu_domain(domain)->smmu;
>
>> + int ret;
>> if (!ops)
>> return -ENODEV;
>> - return ops->map(ops, iova, paddr, size, prot);
>> + arm_smmu_rpm_get(smmu);
>> + ret = ops->map(ops, iova, paddr, size, prot);
>> + arm_smmu_rpm_put(smmu);
>> +
>> + return ret;
>> }
>> static size_t arm_smmu_unmap(struct iommu_domain *domain,
>> unsigned long iova,
>> size_t size)
>> {
>> struct io_pgtable_ops *ops = to_smmu_domain(domain)->pgtbl_ops;
>> + struct arm_smmu_domain *smmu_domain = to_smmu_domain(domain);
>> + struct arm_smmu_device *smmu = smmu_domain->smmu;
>> + size_t ret;
>> if (!ops)
>> return 0;
>> - return ops->unmap(ops, iova, size);
>> + arm_smmu_rpm_get(smmu);
>> + ret = ops->unmap(ops, iova, size);
>> + arm_smmu_rpm_put(smmu);
>> +
>> + return ret;
>> }
>> static void arm_smmu_iotlb_sync(struct iommu_domain *domain)
>> @@ -1407,14 +1450,22 @@ static int arm_smmu_add_device(struct device
>> *dev)
>> while (i--)
>> cfg->smendx[i] = INVALID_SMENDX;
>> + ret = arm_smmu_rpm_get(smmu);
>> + if (ret < 0)
>> + goto out_cfg_free;
>> +
>> ret = arm_smmu_master_alloc_smes(dev);
>
> Nit: it would be easier to just do the rpm_put here; then you don't
> need to mess with the cleanup path.
Sure, will do that. It will be cleaner.
>
>> if (ret)
>> - goto out_cfg_free;
>> + goto out_rpm_put;
>> iommu_device_link(&smmu->iommu, dev);
>> + arm_smmu_rpm_put(smmu);
>> +
>> return 0;
>> +out_rpm_put:
>> + arm_smmu_rpm_put(smmu);
>> out_cfg_free:
>> kfree(cfg);
>> out_free:
>> @@ -1427,7 +1478,7 @@ 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;
>> @@ -1435,8 +1486,15 @@ static void arm_smmu_remove_device(struct
>> device *dev)
>> cfg = fwspec->iommu_priv;
>> smmu = cfg->smmu;
>> + ret = arm_smmu_rpm_get(smmu);
>> + if (ret < 0)
>> + return;
>> +
>> iommu_device_unlink(&smmu->iommu, dev);
>> arm_smmu_master_free_smes(fwspec);
>> +
>> + arm_smmu_rpm_put(smmu);
>> +
>> iommu_group_remove_device(dev);
>> kfree(fwspec->iommu_priv);
>> iommu_fwspec_free(dev);
>> @@ -2124,6 +2182,8 @@ static int arm_smmu_device_probe(struct
>> platform_device *pdev)
>> smmu->irqs[i] = irq;
>> }
>> + platform_set_drvdata(pdev, smmu);
>> +
>> err = devm_clk_bulk_get(smmu->dev, smmu->num_clks, smmu->clks);
>> if (err)
>> return err;
>> @@ -2132,6 +2192,19 @@ static int arm_smmu_device_probe(struct
>> platform_device *pdev)
>> if (err)
>> return err;
>> + /*
>> + * We want to avoid touching dev->power.lock in fastpaths unless
>> + * it's really going to do something useful - pm_runtime_enabled()
>> + * can serve as an ideal proxy for that decision. So, conditionally
>> + * enable pm_runtime.
>> + */
>> + if (dev->pm_domain)
>> + pm_runtime_enable(dev);
>> +
>> + err = arm_smmu_rpm_get(smmu);
>> + if (err < 0)
>> + return err;
>> +
>> err = arm_smmu_device_cfg_probe(smmu);
>> if (err)
>> return err;
>> @@ -2173,10 +2246,11 @@ 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);
>> + arm_smmu_rpm_put(smmu);
>> +
>> /*
>> * For ACPI and generic DT bindings, an SMMU will be probed before
>> * any device which might need it, so we want the bus ops in place
>> @@ -2212,8 +2286,13 @@ static int arm_smmu_device_remove(struct
>> platform_device *pdev)
>> if (!bitmap_empty(smmu->context_map, ARM_SMMU_MAX_CBS))
>> dev_err(&pdev->dev, "removing device with active domains!\n");
>> + arm_smmu_rpm_get(smmu);
>> /* Turn the thing off */
>> writel(sCR0_CLIENTPD, ARM_SMMU_GR0_NS(smmu) + ARM_SMMU_GR0_sCR0);
>> + arm_smmu_rpm_put(smmu);
>> +
>> + if (pm_runtime_enabled(smmu->dev))
>> + pm_runtime_disable(smmu->dev);
>> clk_bulk_unprepare(smmu->num_clks, smmu->clks);
>
> I don't know how runtime and system PM interact - does the reset in
> arm_smmu_pm_resume need special treatment as well, or is the device
> guaranteed to be powered up at that point by other means?
So, as Tomasz wrote, we should be okay with this.
Thanks.
regards
Vivek
>
> Robin.
> --
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