Re: [PATCH v9 3/3] iommu/arm-smmu-v3: Add workaround for Cavium ThunderX2 erratum #126

Lorenzo Pieralisi
2017-06-23T11:38:05Z

On Fri, Jun 23, 2017 at 11:28:05AM +0530, Geetha sowjanya wrote:

[...]

> --- a/drivers/acpi/arm64/iort.c
> +++ b/drivers/acpi/arm64/iort.c
> @@ -828,6 +828,18 @@ static int __init arm_smmu_v3_count_resources(struct acpi_iort_node *node)
> return num_res;
> }
>
> +static bool arm_smmu_v3_is_combined_irq(struct acpi_iort_smmu_v3 *smmu)
> +{
> + /*
> + * Cavium ThunderX2 implementation doesn't not support unique
> + * irq line. Use single irq line for all the SMMUv3 interrupts.
> + */
> + if (smmu->model == ACPI_IORT_SMMU_V3_CAVIUM_CN99XX)
> + return true;
> +
> + return false;
> +}
> +
> static unsigned long arm_smmu_v3_resource_size(struct acpi_iort_smmu_v3 *smmu)
> {
> /*
> @@ -855,26 +867,32 @@ static void __init arm_smmu_v3_init_resources(struct resource *res,
> res[num_res].flags = IORESOURCE_MEM;
>
> num_res++;
> -
> - if (smmu->event_gsiv)
> - acpi_iort_register_irq(smmu->event_gsiv, "eventq",
> - ACPI_EDGE_SENSITIVE,
> - &res[num_res++]);
> -
> - if (smmu->pri_gsiv)
> - acpi_iort_register_irq(smmu->pri_gsiv, "priq",
> - ACPI_EDGE_SENSITIVE,
> - &res[num_res++]);
> -
> - if (smmu->gerr_gsiv)
> - acpi_iort_register_irq(smmu->gerr_gsiv, "gerror",
> - ACPI_EDGE_SENSITIVE,
> - &res[num_res++]);
> -
> - if (smmu->sync_gsiv)
> - acpi_iort_register_irq(smmu->sync_gsiv, "cmdq-sync",
> + if (arm_smmu_v3_is_combined_irq(smmu))
> + acpi_iort_register_irq(smmu->event_gsiv, "combined",
> ACPI_EDGE_SENSITIVE,
> &res[num_res++]);

I think you should add a check to make sure ALL gsiv are the same
in the IORT table, if they are not the combined IRQ must not be
registered.

Ideally we should add a patch that adds a return value to the
iommu_init_resource callback (ie so that we can prevent allocating
the platform device on error return value) but we are late -rc6
and I won't be able to read mailing lists next week so it is a bit
tight, adding the check above should be quick to do.

Lorenzo

> + else {
> +
> + if (smmu->event_gsiv)
> + acpi_iort_register_irq(smmu->event_gsiv, "eventq",
> + ACPI_EDGE_SENSITIVE,
> + &res[num_res++]);
> +
> + if (smmu->pri_gsiv)
> + acpi_iort_register_irq(smmu->pri_gsiv, "priq",
> + ACPI_EDGE_SENSITIVE,
> + &res[num_res++]);
> +
> + if (smmu->gerr_gsiv)
> + acpi_iort_register_irq(smmu->gerr_gsiv, "gerror",
> + ACPI_EDGE_SENSITIVE,
> + &res[num_res++]);
> +
> + if (smmu->sync_gsiv)
> + acpi_iort_register_irq(smmu->sync_gsiv, "cmdq-sync",
> + ACPI_EDGE_SENSITIVE,
> + &res[num_res++]);
> + }
> }
>
> static bool __init arm_smmu_v3_is_coherent(struct acpi_iort_node *node)
> diff --git a/drivers/iommu/arm-smmu-v3.c b/drivers/iommu/arm-smmu-v3.c
> index 2dea4a9..fd5a48c 100644
> --- a/drivers/iommu/arm-smmu-v3.c
> +++ b/drivers/iommu/arm-smmu-v3.c
> @@ -605,6 +605,7 @@ struct arm_smmu_device {
> struct arm_smmu_priq priq;
>
> int gerr_irq;
> + int combined_irq;
>
> unsigned long ias; /* IPA */
> unsigned long oas; /* PA */
> @@ -1314,6 +1315,24 @@ static irqreturn_t arm_smmu_gerror_handler(int irq, void *dev)
> return IRQ_HANDLED;
> }
>
> +static irqreturn_t arm_smmu_combined_irq_thread(int irq, void *dev)
> +{
> + struct arm_smmu_device *smmu = dev;
> +
> + arm_smmu_evtq_thread(irq, dev);
> + if (smmu->features & ARM_SMMU_FEAT_PRI)
> + arm_smmu_priq_thread(irq, dev);
> +
> + return IRQ_HANDLED;
> +}
> +
> +static irqreturn_t arm_smmu_combined_irq_handler(int irq, void *dev)
> +{
> + arm_smmu_gerror_handler(irq, dev);
> + arm_smmu_cmdq_sync_handler(irq, dev);
> + return IRQ_WAKE_THREAD;
> +}
> +
> /* IO_PGTABLE API */
> static void __arm_smmu_tlb_sync(struct arm_smmu_device *smmu)
> {
> @@ -2230,18 +2249,9 @@ static void arm_smmu_setup_msis(struct arm_smmu_device *smmu)
> devm_add_action(dev, arm_smmu_free_msis, dev);
> }
>
> -static int arm_smmu_setup_irqs(struct arm_smmu_device *smmu)
> +static void arm_smmu_setup_unique_irqs(struct arm_smmu_device *smmu)
> {
> - int ret, irq;
> - u32 irqen_flags = IRQ_CTRL_EVTQ_IRQEN | IRQ_CTRL_GERROR_IRQEN;
> -
> - /* Disable IRQs first */
> - ret = arm_smmu_write_reg_sync(smmu, 0, ARM_SMMU_IRQ_CTRL,
> - ARM_SMMU_IRQ_CTRLACK);
> - if (ret) {
> - dev_err(smmu->dev, "failed to disable irqs\n");
> - return ret;
> - }
> + int irq, ret;
>
> arm_smmu_setup_msis(smmu);
>
> @@ -2284,10 +2294,41 @@ static int arm_smmu_setup_irqs(struct arm_smmu_device *smmu)
> if (ret < 0)
> dev_warn(smmu->dev,
> "failed to enable priq irq\n");
> - else
> - irqen_flags |= IRQ_CTRL_PRIQ_IRQEN;
> }
> }
> +}
> +
> +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;
> +
> + /* Disable IRQs first */
> + ret = arm_smmu_write_reg_sync(smmu, 0, ARM_SMMU_IRQ_CTRL,
> + ARM_SMMU_IRQ_CTRLACK);
> + if (ret) {
> + dev_err(smmu->dev, "failed to disable irqs\n");
> + return ret;
> + }
> +
> + irq = smmu->combined_irq;
> + if (irq) {
> + /*
> + * Cavium ThunderX2 implementation doesn't not support unique
> + * irq lines. Use single irq line for all the SMMUv3 interrupts.
> + */
> + ret = devm_request_threaded_irq(smmu->dev, irq,
> + arm_smmu_combined_irq_handler,
> + arm_smmu_combined_irq_thread,
> + IRQF_ONESHOT,
> + "arm-smmu-v3-combined-irq", smmu);
> + if (ret < 0)
> + dev_warn(smmu->dev, "failed to enable combined irq\n");
> + } else
> + arm_smmu_setup_unique_irqs(smmu);
> +
> + if (smmu->features & ARM_SMMU_FEAT_PRI)
> + irqen_flags |= IRQ_CTRL_PRIQ_IRQEN;
>
> /* Enable interrupt generation on the SMMU */
> ret = arm_smmu_write_reg_sync(smmu, irqen_flags,
> @@ -2724,22 +2765,27 @@ static int arm_smmu_device_probe(struct platform_device *pdev)
> return PTR_ERR(smmu->base);
>
> /* Interrupt lines */
> - irq = platform_get_irq_byname(pdev, "eventq");
> - if (irq > 0)
> - smmu->evtq.q.irq = irq;
>
> - irq = platform_get_irq_byname(pdev, "priq");
> + irq = platform_get_irq_byname(pdev, "combined");
> if (irq > 0)
> - smmu->priq.q.irq = irq;
> + smmu->combined_irq = irq;
> + else {
> + irq = platform_get_irq_byname(pdev, "eventq");
> + if (irq > 0)
> + smmu->evtq.q.irq = irq;
>
> - irq = platform_get_irq_byname(pdev, "cmdq-sync");
> - if (irq > 0)
> - smmu->cmdq.q.irq = irq;
> + irq = platform_get_irq_byname(pdev, "priq");
> + if (irq > 0)
> + smmu->priq.q.irq = irq;
>
> - irq = platform_get_irq_byname(pdev, "gerror");
> - if (irq > 0)
> - smmu->gerr_irq = irq;
> + irq = platform_get_irq_byname(pdev, "cmdq-sync");
> + if (irq > 0)
> + smmu->cmdq.q.irq = irq;
>
> + irq = platform_get_irq_byname(pdev, "gerror");
> + if (irq > 0)
> + smmu->gerr_irq = irq;
> + }
> /* Probe the h/w */
> ret = arm_smmu_device_hw_probe(smmu);
> if (ret)
> --
> 1.7.1
>