2018-01-20 18:09:16

by Nate Watterson

Subject: [PATCH v2] iommu/arm-smmu-v3: limit reporting of MSI allocation failures

Currently, the arm-smmu-v3 driver expects to allocate MSIs for all SMMUs
with FEAT_MSI set. This results in unwarranted "failed to allocate MSIs"
warnings being printed on systems where FW was either deliberately
configured to force the use of SMMU wired interrupts -or- is altogether
incapable of describing SMMU MSI topology (ACPI IORT prior to rev.C).

Remedy this by checking msi_domain before attempting to allocate SMMU
MSIs.

Signed-off-by: Nate Watterson <[email protected]>
Signed-off-by: Sinan Kaya <[email protected]>
---
drivers/iommu/arm-smmu-v3.c | 7 ++++++-
1 file changed, 6 insertions(+), 1 deletion(-)

diff --git a/drivers/iommu/arm-smmu-v3.c b/drivers/iommu/arm-smmu-v3.c
index 744592d..00de028 100644
--- a/drivers/iommu/arm-smmu-v3.c
+++ b/drivers/iommu/arm-smmu-v3.c
@@ -2328,10 +2328,15 @@ static void arm_smmu_setup_msis(struct arm_smmu_device *smmu)
if (!(smmu->features & ARM_SMMU_FEAT_MSI))
return;

+ if (!dev->msi_domain) {
+ dev_info(smmu->dev, "msi_domain absent - falling back to wired irqs\n");
+ return;
+ }
+
/* Allocate MSIs for evtq, gerror and priq. Ignore cmdq */
ret = platform_msi_domain_alloc_irqs(dev, nvec, arm_smmu_write_msi_msg);
if (ret) {
- dev_warn(dev, "failed to allocate MSIs\n");
+ dev_warn(dev, "failed to allocate MSIs - falling back to wired irqs\n");
return;
}

--
Qualcomm Datacenter Technologies, Inc. on behalf of Qualcomm Technologies, Inc.
Qualcomm Technologies, Inc. is a member of the Code Aurora Forum, a Linux
Foundation Collaborative Project.

2018-01-22 11:45:54

by Marc Zyngier

Subject: Re: [PATCH v2] iommu/arm-smmu-v3: limit reporting of MSI allocation failures

On 20/01/18 18:08, Nate Watterson wrote:
> Currently, the arm-smmu-v3 driver expects to allocate MSIs for all SMMUs
> with FEAT_MSI set. This results in unwarranted "failed to allocate MSIs"
> warnings being printed on systems where FW was either deliberately
> configured to force the use of SMMU wired interrupts -or- is altogether
> incapable of describing SMMU MSI topology (ACPI IORT prior to rev.C).
>
> Remedy this by checking msi_domain before attempting to allocate SMMU
> MSIs.
>
> Signed-off-by: Nate Watterson <[email protected]>
> Signed-off-by: Sinan Kaya <[email protected]>
> ---
> drivers/iommu/arm-smmu-v3.c | 7 ++++++-
> 1 file changed, 6 insertions(+), 1 deletion(-)
>
> diff --git a/drivers/iommu/arm-smmu-v3.c b/drivers/iommu/arm-smmu-v3.c
> index 744592d..00de028 100644
> --- a/drivers/iommu/arm-smmu-v3.c
> +++ b/drivers/iommu/arm-smmu-v3.c
> @@ -2328,10 +2328,15 @@ static void arm_smmu_setup_msis(struct arm_smmu_device *smmu)
> if (!(smmu->features & ARM_SMMU_FEAT_MSI))
> return;
>
> + if (!dev->msi_domain) {
> + dev_info(smmu->dev, "msi_domain absent - falling back to wired irqs\n");
> + return;
> + }
> +
> /* Allocate MSIs for evtq, gerror and priq. Ignore cmdq */
> ret = platform_msi_domain_alloc_irqs(dev, nvec, arm_smmu_write_msi_msg);
> if (ret) {
> - dev_warn(dev, "failed to allocate MSIs\n");
> + dev_warn(dev, "failed to allocate MSIs - falling back to wired irqs\n");
> return;
> }
>
>

Acked-by: Marc Zyngier <[email protected]>

M.
--
Jazz is not dead. It just smells funny...