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Message-ID: <CANHdaiaw4sB+bMY8LcyQGXbnAfKNk5zX6_893M0gqKrVNmeFuQ@mail.gmail.com>
Date: Mon, 8 May 2017 17:32:34 +0530
From: Geetha Akula <geethasowjanya.akula@...il.com>
To: Robin Murphy <robin.murphy@....com>
Cc: Geetha sowjanya <gakula@...iumnetworks.com>,
Will Deacon <will.deacon@....com>, lorenzo.pieralisi@....com,
Hanjun Guo <hanjun.guo@...aro.org>, sudeep.holla@....com,
iommu@...ts.linux-foundation.org, jcm@...hat.com,
linux-kernel@...r.kernel.org,
Robert Richter <robert.richter@...ium.com>,
catalin.marinas@....com, Sunil Goutham <sgoutham@...ium.com>,
linux-arm-kernel@...ts.infradead.org, linux-acpi@...r.kernel.org,
Linu Cherian <linu.cherian@...ium.com>,
Geetha Sowjanya <geethasowjanya.akula@...ium.com>
Subject: Re: [PATCH v3 6/7] iommu/arm-smmu-v3: Add workaround for Cavium
ThunderX2 erratum #126
On Mon, May 8, 2017 at 4:51 PM, Robin Murphy <robin.murphy@....com> wrote:
> On 05/05/17 13:08, Geetha sowjanya wrote:
>> From: Geetha Sowjanya <geethasowjanya.akula@...ium.com>
>>
>> Cavium ThunderX2 SMMU doesn't support MSI and also doesn't have unique irq
>> lines for gerror, eventq and cmdq-sync.
>>
>> This patch addresses the issue by checking if any interrupt sources are
>> using same irq number, then they are registered as shared irqs.
>>
>> Signed-off-by: Geetha Sowjanya <geethasowjanya.akula@...ium.com>
>> ---
>> drivers/iommu/arm-smmu-v3.c | 32 ++++++++++++++++++++++++++++----
>> 1 file changed, 28 insertions(+), 4 deletions(-)
>>
>> diff --git a/drivers/iommu/arm-smmu-v3.c b/drivers/iommu/arm-smmu-v3.c
>> index 016b702..46428e7 100644
>> --- a/drivers/iommu/arm-smmu-v3.c
>> +++ b/drivers/iommu/arm-smmu-v3.c
>> @@ -2236,10 +2236,30 @@ static void arm_smmu_setup_msis(struct arm_smmu_device *smmu)
>> devm_add_action(dev, arm_smmu_free_msis, dev);
>> }
>>
>> +static int get_irq_flags(struct arm_smmu_device *smmu, int irq)
>> +{
>> + int match_count = 0;
>> +
>> + if (irq == smmu->evtq.q.irq)
>> + match_count++;
>> + if (irq == smmu->cmdq.q.irq)
>> + match_count++;
>> + if (irq == smmu->gerr_irq)
>> + match_count++;
>> + if (irq == smmu->priq.q.irq)
>> + match_count++;
>> +
>> + if (match_count > 1)
>> + return IRQF_SHARED | IRQF_ONESHOT;
>> +
>> + return 0;
>
> I'd say just have this return IRQF_ONESHOT in the non-shared case...
>
>> +}
>> +
>> static int arm_smmu_setup_irqs(struct arm_smmu_device *smmu)
>> {
>> int ret, irq;
>> u32 irqen_flags = IRQ_CTRL_EVTQ_IRQEN | IRQ_CTRL_GERROR_IRQEN;
>> + u32 irqflags = 0;
>>
>> /* Disable IRQs first */
>> ret = arm_smmu_write_reg_sync(smmu, 0, ARM_SMMU_IRQ_CTRL,
>> @@ -2254,9 +2274,10 @@ static int arm_smmu_setup_irqs(struct arm_smmu_device *smmu)
>> /* Request interrupt lines */
>> irq = smmu->evtq.q.irq;
>> if (irq) {
>> + irqflags = get_irq_flags(smmu, irq);
>> ret = devm_request_threaded_irq(smmu->dev, irq, NULL,
>> arm_smmu_evtq_thread,
>> - IRQF_ONESHOT,
>> + IRQF_ONESHOT | irqflags,
>
> ...and pass get_irq_flags(smmu, irq) directly as the argument here.
>
> The local variable and intermediate logic only seem to add unnecessary
> complexity, given that the two cases we actually end up with are:
>
> IRQF_ONESHOT | 0
>
> vs.
>
> IRQF_ONESHOT | IRQF_SHARED | IRQF_ONESHOT
>
> neither of which looks particularly sensible.
>
> Robin.
>
I will resubmit the patch with suggested changes.
Thank you,
Geetha.
>> "arm-smmu-v3-evtq", smmu);
>> if (ret < 0)
>> dev_warn(smmu->dev, "failed to enable evtq irq\n");
>> @@ -2264,8 +2285,9 @@ static int arm_smmu_setup_irqs(struct arm_smmu_device *smmu)
>>
>> irq = smmu->cmdq.q.irq;
>> if (irq) {
>> + irqflags = get_irq_flags(smmu, irq);
>> ret = devm_request_irq(smmu->dev, irq,
>> - arm_smmu_cmdq_sync_handler, 0,
>> + arm_smmu_cmdq_sync_handler, irqflags,
>> "arm-smmu-v3-cmdq-sync", smmu);
>> if (ret < 0)
>> dev_warn(smmu->dev, "failed to enable cmdq-sync irq\n");
>> @@ -2273,8 +2295,9 @@ static int arm_smmu_setup_irqs(struct arm_smmu_device *smmu)
>>
>> irq = smmu->gerr_irq;
>> if (irq) {
>> + irqflags = get_irq_flags(smmu, irq);
>> ret = devm_request_irq(smmu->dev, irq, arm_smmu_gerror_handler,
>> - 0, "arm-smmu-v3-gerror", smmu);
>> + irqflags, "arm-smmu-v3-gerror", smmu);
>> if (ret < 0)
>> dev_warn(smmu->dev, "failed to enable gerror irq\n");
>> }
>> @@ -2282,9 +2305,10 @@ static int arm_smmu_setup_irqs(struct arm_smmu_device *smmu)
>> if (smmu->features & ARM_SMMU_FEAT_PRI) {
>> irq = smmu->priq.q.irq;
>> if (irq) {
>> + irqflags = get_irq_flags(smmu, irq);
>> ret = devm_request_threaded_irq(smmu->dev, irq, NULL,
>> arm_smmu_priq_thread,
>> - IRQF_ONESHOT,
>> + IRQF_ONESHOT | irqflags,
>> "arm-smmu-v3-priq",
>> smmu);
>> if (ret < 0)
>>
>
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