[External] [RFC PATCH v2 02/10] iommu/riscv: support HPM and interrupt handling

[yunhui cui]

Add Luxu in the loop.

On Fri, Jun 14, 2024 at 10:22 PM Zong Li <zong.li at sifive.com> wrote:
>
> This patch initialize the pmu stuff and uninitialize it when driver
> removing. The interrupt handling is also provided, this handler need to
> be primary handler instead of thread function, because pt_regs is empty
> when threading the IRQ, but pt_regs is necessary by perf_event_overflow.
>
> Signed-off-by: Zong Li <zong.li at sifive.com>
> ---
>  drivers/iommu/riscv/iommu.c | 65 +++++++++++++++++++++++++++++++++++++
>  1 file changed, 65 insertions(+)
>
> diff --git a/drivers/iommu/riscv/iommu.c b/drivers/iommu/riscv/iommu.c
> index 8b6a64c1ad8d..1716b2251f38 100644
> --- a/drivers/iommu/riscv/iommu.c
> +++ b/drivers/iommu/riscv/iommu.c
> @@ -540,6 +540,62 @@ static irqreturn_t riscv_iommu_fltq_process(int irq, void *data)
>         return IRQ_HANDLED;
>  }
>
> +/*
> + * IOMMU Hardware performance monitor
> + */
> +
> +/* HPM interrupt primary handler */
> +static irqreturn_t riscv_iommu_hpm_irq_handler(int irq, void *dev_id)
> +{
> +       struct riscv_iommu_device *iommu = (struct riscv_iommu_device *)dev_id;
> +
> +       /* Process pmu irq */
> +       riscv_iommu_pmu_handle_irq(&iommu->pmu);
> +
> +       /* Clear performance monitoring interrupt pending */
> +       riscv_iommu_writel(iommu, RISCV_IOMMU_REG_IPSR, RISCV_IOMMU_IPSR_PMIP);
> +
> +       return IRQ_HANDLED;
> +}
> +
> +/* HPM initialization */
> +static int riscv_iommu_hpm_enable(struct riscv_iommu_device *iommu)
> +{
> +       int rc;
> +
> +       if (!(iommu->caps & RISCV_IOMMU_CAPABILITIES_HPM))
> +               return 0;
> +
> +       /*
> +        * pt_regs is empty when threading the IRQ, but pt_regs is necessary
> +        * by perf_event_overflow. Use primary handler instead of thread
> +        * function for PM IRQ.
> +        *
> +        * Set the IRQF_ONESHOT flag because this IRQ might be shared with
> +        * other threaded IRQs by other queues.
> +        */
> +       rc = devm_request_irq(iommu->dev,
> +                             iommu->irqs[riscv_iommu_queue_vec(iommu, RISCV_IOMMU_IPSR_PMIP)],
> +                             riscv_iommu_hpm_irq_handler, IRQF_ONESHOT | IRQF_SHARED, NULL, iommu);
> +       if (rc)
> +               return rc;
> +
> +       return riscv_iommu_pmu_init(&iommu->pmu, iommu->reg, dev_name(iommu->dev));
> +}
> +
> +/* HPM uninitialization */
> +static void riscv_iommu_hpm_disable(struct riscv_iommu_device *iommu)
> +{
> +       if (!(iommu->caps & RISCV_IOMMU_CAPABILITIES_HPM))
> +               return;
> +
> +       devm_free_irq(iommu->dev,
> +                     iommu->irqs[riscv_iommu_queue_vec(iommu, RISCV_IOMMU_IPSR_PMIP)],
> +                     iommu);
> +
> +       riscv_iommu_pmu_uninit(&iommu->pmu);
> +}
> +
>  /* Lookup and initialize device context info structure. */
>  static struct riscv_iommu_dc *riscv_iommu_get_dc(struct riscv_iommu_device *iommu,
>                                                  unsigned int devid)
> @@ -1612,6 +1668,9 @@ void riscv_iommu_remove(struct riscv_iommu_device *iommu)
>         riscv_iommu_iodir_set_mode(iommu, RISCV_IOMMU_DDTP_IOMMU_MODE_OFF);
>         riscv_iommu_queue_disable(&iommu->cmdq);
>         riscv_iommu_queue_disable(&iommu->fltq);
> +
> +       if (iommu->caps & RISCV_IOMMU_CAPABILITIES_HPM)
> +               riscv_iommu_pmu_uninit(&iommu->pmu);
>  }
>
>  int riscv_iommu_init(struct riscv_iommu_device *iommu)
> @@ -1651,6 +1710,10 @@ int riscv_iommu_init(struct riscv_iommu_device *iommu)
>         if (rc)
>                 goto err_queue_disable;
>
> +       rc = riscv_iommu_hpm_enable(iommu);
> +       if (rc)
> +               goto err_hpm_disable;
> +
>         rc = iommu_device_sysfs_add(&iommu->iommu, NULL, NULL, "riscv-iommu@%s",
>                                     dev_name(iommu->dev));
>         if (rc) {
> @@ -1669,6 +1732,8 @@ int riscv_iommu_init(struct riscv_iommu_device *iommu)
>  err_remove_sysfs:
>         iommu_device_sysfs_remove(&iommu->iommu);
>  err_iodir_off:
> +       riscv_iommu_hpm_disable(iommu);
> +err_hpm_disable:
>         riscv_iommu_iodir_set_mode(iommu, RISCV_IOMMU_DDTP_IOMMU_MODE_OFF);
>  err_queue_disable:
>         riscv_iommu_queue_disable(&iommu->fltq);
> --
> 2.17.1
>
>

Thanks,
Yunhui