linux-kernel - Re: [PATCH V4 3/6] iommu/arm-smmu: Invoke pm_runtime during probe, add/remove device

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Message-ID: <5ee0bacd-e557-a6c4-a897-844fb12ea6ae@codeaurora.org>
Date:   Thu, 13 Jul 2017 10:43:59 +0530
From:   Vivek Gautam <vivek.gautam@...eaurora.org>
To:     Stephen Boyd <sboyd@...eaurora.org>
Cc:     joro@...tes.org, robin.murphy@....com, robh+dt@...nel.org,
        mark.rutland@....com, will.deacon@....com,
        m.szyprowski@...sung.com, robdclark@...il.com,
        iommu@...ts.linux-foundation.org, devicetree@...r.kernel.org,
        linux-kernel@...r.kernel.org, linux-clk@...r.kernel.org,
        linux-arm-msm@...r.kernel.org, sricharan@...eaurora.org,
        stanimir.varbanov@...aro.org, architt@...eaurora.org,
        linux-arm-kernel@...ts.infradead.org
Subject: Re: [PATCH V4 3/6] iommu/arm-smmu: Invoke pm_runtime during probe,
 add/remove device

Hi Stephen,


On 07/13/2017 04:24 AM, Stephen Boyd wrote:
> On 07/06, Vivek Gautam wrote:
>> @@ -1231,12 +1237,18 @@ static int arm_smmu_map(struct iommu_domain *domain, unsigned long iova,
>>   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 io_pgtable_ops *ops = smmu_domain->pgtbl_ops;
>> +	size_t ret;
>>   
>>   	if (!ops)
>>   		return 0;
>>   
>> -	return ops->unmap(ops, iova, size);
>> +	pm_runtime_get_sync(smmu_domain->smmu->dev);
> Can these map/unmap ops be called from an atomic context? I seem
> to recall that being a problem before.

That's something which was dropped in the following patch merged in master:
523d7423e21b iommu/arm-smmu: Remove io-pgtable spinlock

Looks like we don't  need locks here anymore?

Best Regards
Vivek

>
>
>> +	ret = ops->unmap(ops, iova, size);
>> +	pm_runtime_put_sync(smmu_domain->smmu->dev);
>> +
>> +	return ret;
>>   }
>>   
>>   static phys_addr_t arm_smmu_iova_to_phys_hard(struct iommu_domain *domain,

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