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SubjectRe: [PATCH v9 3/5] iommu/arm-smmu: Invoke pm_runtime during probe, add/remove device
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On 13/03/18 08:55, 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>
> Reviewed-by: Tomasz Figa <tfiga@chromium.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).

> + 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.

> 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?

Robin.

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