Date:   Wed, 7 Mar 2018 12:38:08 +0000
From:   Robin Murphy <robin.murphy@....com>
To:     Vivek Gautam <vivek.gautam@...eaurora.org>, joro@...tes.org,
        robh+dt@...nel.org, mark.rutland@....com, rjw@...ysocki.net,
        will.deacon@....com, robdclark@...il.com,
        iommu@...ts.linux-foundation.org, devicetree@...r.kernel.org,
        linux-kernel@...r.kernel.org
Cc:     tfiga@...omium.org, jcrouse@...eaurora.org, sboyd@...eaurora.org,
        sricharan@...eaurora.org, m.szyprowski@...sung.com,
        architt@...eaurora.org, linux-arm-msm@...r.kernel.org
Subject: Re: [PATCH v8 3/5] iommu/arm-smmu: Invoke pm_runtime during probe,
 add/remove device

On 02/03/18 10:10, 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>
> ---
>   drivers/iommu/arm-smmu.c | 96 ++++++++++++++++++++++++++++++++++++++++++++----
>   1 file changed, 88 insertions(+), 8 deletions(-)
> 
> diff --git a/drivers/iommu/arm-smmu.c b/drivers/iommu/arm-smmu.c
> index c8b16f53f597..3d6a1875431f 100644
> --- a/drivers/iommu/arm-smmu.c
> +++ b/drivers/iommu/arm-smmu.c
> @@ -209,6 +209,8 @@ struct arm_smmu_device {
>   	struct clk_bulk_data		*clks;
>   	int				num_clks;
>   
> +	bool				rpm_supported;
> +

Can we not automatically infer this from whether clocks and/or power 
domains are specified or not, then just use pm_runtime_enabled() as the 
fast-path check as Tomasz originally proposed?

I worry that relying on statically-defined matchdata is just going to 
blow up the driver and DT binding into a maintenance nightmare; I really 
don't want to start needing separate definitions for e.g. 
"arm,juno-etr-mmu-401" and "arm,juno-hdlcd-mmu-401" just because one 
otherwise-identical instance within the SoC is in a separate 
controllable power domain while the others aren't.

Robin.

>   	u32				cavium_id_base; /* Specific to Cavium */
>   
>   	spinlock_t			global_sync_lock;
> @@ -268,6 +270,20 @@ static struct arm_smmu_option_prop arm_smmu_options[] = {
>   	{ 0, NULL},
>   };
>   
> +static inline int arm_smmu_rpm_get(struct arm_smmu_device *smmu)
> +{
> +	if (smmu->rpm_supported)
> +		return pm_runtime_get_sync(smmu->dev);
> +
> +	return 0;
> +}
> +
> +static inline void arm_smmu_rpm_put(struct arm_smmu_device *smmu)
> +{
> +	if (smmu->rpm_supported)
> +		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 +929,15 @@ 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 +952,8 @@ 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 +1235,15 @@ 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
> @@ -1231,10 +1258,17 @@ 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);
> +
> +	arm_smmu_rpm_put(smmu);
> +
> +	return ret;
>   
>   destroy_domain:
>   	arm_smmu_destroy_domain_context(domain);
> +rpm_put:
> +	arm_smmu_rpm_put(smmu);
> +
>   	return ret;
>   }
>   
> @@ -1242,22 +1276,36 @@ 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;
> +	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)
> @@ -1412,14 +1460,22 @@ 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);
>   	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:
> @@ -1432,7 +1488,7 @@ 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;
> @@ -1440,8 +1496,15 @@ 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);
> @@ -1907,6 +1970,7 @@ struct arm_smmu_match_data {
>   	enum arm_smmu_implementation model;
>   	const char * const *clks;
>   	int num_clks;
> +	bool rpm_supported;
>   };
>   
>   #define ARM_SMMU_MATCH_DATA(name, ver, imp)	\
> @@ -2029,6 +2093,7 @@ static int arm_smmu_device_dt_probe(struct platform_device *pdev,
>   	smmu->version = data->version;
>   	smmu->model = data->model;
>   	smmu->num_clks = data->num_clks;
> +	smmu->rpm_supported = data->rpm_supported;
>   
>   	arm_smmu_fill_clk_data(smmu, data->clks);
>   
> @@ -2129,6 +2194,8 @@ 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;
> @@ -2137,6 +2204,13 @@ static int arm_smmu_device_probe(struct platform_device *pdev)
>   	if (err)
>   		return err;
>   
> +	if (smmu->rpm_supported)
> +		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;
> @@ -2178,10 +2252,11 @@ 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
> @@ -2217,9 +2292,14 @@ 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 (smmu->rpm_supported)
> +		pm_runtime_disable(smmu->dev);
> +
>   	clk_bulk_unprepare(smmu->num_clks, smmu->clks);
>   
>   	return 0;
> 

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