linux-kernel - Re: [RESEND PATCH v17 2/5] iommu/arm-smmu: Invoke pm

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Date:   Mon, 26 Nov 2018 11:33:15 +0530
From:   Vivek Gautam <vivek.gautam@...eaurora.org>
To:     Will Deacon <will.deacon@....com>
Cc:     Mark Rutland <mark.rutland@....com>,
        "open list:OPEN FIRMWARE AND FLATTENED DEVICE TREE BINDINGS" 
        <devicetree@...r.kernel.org>, alex.williamson@...hat.com,
        Linux PM <linux-pm@...r.kernel.org>, sboyd@...nel.org,
        freedreno <freedreno@...ts.freedesktop.org>,
        "Rafael J. Wysocki" <rjw@...ysocki.net>,
        open list <linux-kernel@...r.kernel.org>,
        "list@....net:IOMMU DRIVERS" <iommu@...ts.linux-foundation.org>,
        Joerg Roedel <joro@...tes.org>,
        iommu@...ts.linux-foundation.org, robh+dt <robh+dt@...nel.org>,
        linux-arm-msm <linux-arm-msm@...r.kernel.org>,
        Robin Murphy <robin.murphy@....com>
Subject: Re: [RESEND PATCH v17 2/5] iommu/arm-smmu: Invoke pm_runtime during
 probe, add/remove device



On 11/24/2018 12:06 AM, Will Deacon wrote:
> On Thu, Nov 22, 2018 at 05:32:24PM +0530, Vivek Gautam wrote:
>> Hi Will,
>>
>> On Wed, Nov 21, 2018 at 11:09 PM Will Deacon <will.deacon@....com> wrote:
>>> On Fri, Nov 16, 2018 at 04:54:27PM +0530, 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.
>>>> Global locks are also initialized before enabling runtime pm as the
>>>> runtime_resume() calls device_reset() which does tlb_sync_global()
>>>> that ultimately requires locks to be initialized.
>>>>
>>>> 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>
>>>> Tested-by: Srinivas Kandagatla <srinivas.kandagatla@...aro.org>
>>>> Reviewed-by: Robin Murphy <robin.murphy@....com>
>>>> ---
>>>>   drivers/iommu/arm-smmu.c | 101 ++++++++++++++++++++++++++++++++++++++++++-----
>>>>   1 file changed, 91 insertions(+), 10 deletions(-)
>>> Given that you're doing the get/put in the TLBI ops unconditionally:
>>>
>>>>   static void arm_smmu_flush_iotlb_all(struct iommu_domain *domain)
>>>>   {
>>>>        struct arm_smmu_domain *smmu_domain = to_smmu_domain(domain);
>>>> +     struct arm_smmu_device *smmu = smmu_domain->smmu;
>>>>
>>>> -     if (smmu_domain->tlb_ops)
>>>> +     if (smmu_domain->tlb_ops) {
>>>> +             arm_smmu_rpm_get(smmu);
>>>>                smmu_domain->tlb_ops->tlb_flush_all(smmu_domain);
>>>> +             arm_smmu_rpm_put(smmu);
>>>> +     }
>>>>   }
>>>>
>>>>   static void arm_smmu_iotlb_sync(struct iommu_domain *domain)
>>>>   {
>>>>        struct arm_smmu_domain *smmu_domain = to_smmu_domain(domain);
>>>> +     struct arm_smmu_device *smmu = smmu_domain->smmu;
>>>>
>>>> -     if (smmu_domain->tlb_ops)
>>>> +     if (smmu_domain->tlb_ops) {
>>>> +             arm_smmu_rpm_get(smmu);
>>>>                smmu_domain->tlb_ops->tlb_sync(smmu_domain);
>>>> +             arm_smmu_rpm_put(smmu);
>>>> +     }
>>> Why do you need them around the map/unmap calls as well?
>> We still have .tlb_add_flush path?
> Ok, so we could add the ops around that as well. Right now, we've got
> the runtime pm hooks crossing two parts of the API.

Sure, will do that then, and remove the runtime pm hooks from map/unmap.

Thanks
Vivek
>
> Will