Hi Marc,
On Tue, Oct 06, 2015 at 07:15:26PM +0100, Marc Zyngier wrote:
> Despite being a platform device, the SMMUv3 is capable of signaling
> interrupts using MSIs. Hook it into the platform MSI framework and
> enjoy faults being reported in a new and exciting way.
>
> Signed-off-by: Marc Zyngier <[email protected]>
> ---
> Now rebased on top of Will's iommu/devel branch, which leads to
> a slightly different patch.
>
> drivers/iommu/arm-smmu-v3.c | 82
> ++++++++++++++++++++++++++++++++++++++++++---
> 1 file changed, 78 insertions(+), 4 deletions(-)
>
> diff --git a/drivers/iommu/arm-smmu-v3.c b/drivers/iommu/arm-smmu-v3.c
> index 5b11b77..3ccc8ed 100644
> --- a/drivers/iommu/arm-smmu-v3.c
> +++ b/drivers/iommu/arm-smmu-v3.c
> @@ -26,6 +26,7 @@
> #include <linux/iommu.h>
> #include <linux/iopoll.h>
> #include <linux/module.h>
> +#include <linux/msi.h>
> #include <linux/of.h>
> #include <linux/of_address.h>
> #include <linux/of_platform.h>
> @@ -2176,6 +2177,63 @@ static int arm_smmu_write_reg_sync(struct
> arm_smmu_device *smmu, u32 val,
> 1, ARM_SMMU_POLL_TIMEOUT_US);
> }
>
> +static void arm_smmu_write_msi_msg(struct msi_desc *desc, struct msi_msg
> *msg)
> +{
> + struct device *dev = msi_desc_to_dev(desc);
> + struct arm_smmu_device *smmu = dev_get_drvdata(dev);
> + phys_addr_t cfg0_offset, cfg1_offset, cfg2_offset;
> + phys_addr_t doorbell;
> +
> + switch (desc->platform.msi_index) {
> + case 0: /* EVTQ */
> + cfg0_offset = ARM_SMMU_EVTQ_IRQ_CFG0;
> + cfg1_offset = ARM_SMMU_EVTQ_IRQ_CFG1;
> + cfg2_offset = ARM_SMMU_EVTQ_IRQ_CFG2;
> + break;
> + case 1: /* GERROR */
> + cfg0_offset = ARM_SMMU_GERROR_IRQ_CFG0;
> + cfg1_offset = ARM_SMMU_GERROR_IRQ_CFG1;
> + cfg2_offset = ARM_SMMU_GERROR_IRQ_CFG2;
> + break;
> + case 2: /* PRIQ */
> + cfg0_offset = ARM_SMMU_PRIQ_IRQ_CFG0;
> + cfg1_offset = ARM_SMMU_PRIQ_IRQ_CFG1;
> + cfg2_offset = ARM_SMMU_PRIQ_IRQ_CFG2;
> + break;
Can we have some #defines or an enum for these indices please?
> + default: /* Unknown */
> + return;
> + }
> +
> + doorbell = (((u64)msg->address_hi) << 32) | msg->address_lo;
> + doorbell &= MSI_CFG0_ADDR_MASK << MSI_CFG0_ADDR_SHIFT;
> +
> + writeq_relaxed(doorbell, smmu->base + cfg0_offset);
> + writew_relaxed(msg->data, smmu->base + cfg1_offset);
> + writew_relaxed(MSI_CFG2_MEMATTR_DEVICE_nGnRE,
> + smmu->base + cfg2_offset);
writel_relaxed?
> +}
> +
> +static void arm_smmu_msi_override_irqs(struct arm_smmu_device *smmu)
> +{
> + struct msi_desc *desc;
> +
> + for_each_msi_entry(desc, smmu->dev) {
> + switch (desc->platform.msi_index) {
> + case 0: /* EVTQ */
> + smmu->evtq.q.irq = desc->irq;
> + break;
> + case 1: /* GERROR */
> + smmu->gerr_irq = desc->irq;
> + break;
> + case 2: /* PRIQ */
> + smmu->priq.q.irq = desc->irq;
> + break;
> + default: /* Unknown */
> + continue;
> + }
> + }
> +}
> +
> static int arm_smmu_setup_irqs(struct arm_smmu_device *smmu)
> {
> int ret, irq;
> @@ -2192,6 +2250,23 @@ static int arm_smmu_setup_irqs(struct arm_smmu_device
> *smmu)
> /* Clear the MSI address regs */
> writeq_relaxed(0, smmu->base + ARM_SMMU_GERROR_IRQ_CFG0);
> writeq_relaxed(0, smmu->base + ARM_SMMU_EVTQ_IRQ_CFG0);
> + if (smmu->features & ARM_SMMU_FEAT_PRI)
> + writeq_relaxed(0, smmu->base + ARM_SMMU_PRIQ_IRQ_CFG0);
> +
> + /* Allocate MSIs for evtq, gerror and priq. Ignore cmdq */
> + if (smmu->features & ARM_SMMU_FEAT_MSI) {
We should probably add an IS_ENABLED(CONFIG_MSI) to the feature setting
in arm_smmu_device_probe too.
> + int nvecs = 2;
> +
> + if (smmu->features & ARM_SMMU_FEAT_PRI)
> + nvecs++;
> +
> + ret = platform_msi_domain_alloc_irqs(smmu->dev, nvecs,
> + arm_smmu_write_msi_msg);
Since this is doing kzallocs and stuff we're going to need some extra code
on the failure and teardown paths, methinks. Or you could write a devm_
interface like we have for wired interrupts.
> + if (ret)
> + dev_warn(smmu->dev, "failed to allocate MSIs\n");
> + else
> + arm_smmu_msi_override_irqs(smmu);
> + }
Let's just move all this out into arm_smmu_setup_msi_vecs, which can do
the MSI feature check and zero or configure the MSI cfg register
accordingly.
>
> /* Request wired interrupt lines */
We should probably remove "wired" from this comment now that we could
be overriding the irqs using the MSI descriptors.
Will
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