2017-03-13 10:39:41

by Robert Richter

Subject: [PATCH] iommu/arm-smmu: Print message when Cavium erratum 27704 was detected

Firmware is responsible for properly enabling smmu workarounds. Print
a message for better diagnostics when Cavium erratum 27704 was
detected.

Signed-off-by: Robert Richter <[email protected]>
---
drivers/iommu/arm-smmu.c | 1 +
1 file changed, 1 insertion(+)

diff --git a/drivers/iommu/arm-smmu.c b/drivers/iommu/arm-smmu.c
index abf6496843a6..c88bf8deb958 100644
--- a/drivers/iommu/arm-smmu.c
+++ b/drivers/iommu/arm-smmu.c
@@ -1887,6 +1887,7 @@ static int arm_smmu_device_cfg_probe(struct arm_smmu_device *smmu)
atomic_add_return(smmu->num_context_banks,
&cavium_smmu_context_count);
smmu->cavium_id_base -= smmu->num_context_banks;
+ dev_notice(smmu->dev, "\tenabling workaround for Cavium erratum 27704\n");
}

/* ID2 */
--
2.11.0

2017-03-13 12:15:47

by Robin Murphy

Subject: Re: [PATCH] iommu/arm-smmu: Print message when Cavium erratum 27704 was detected

On 13/03/17 10:39, Robert Richter wrote:
> Firmware is responsible for properly enabling smmu workarounds. Print
> a message for better diagnostics when Cavium erratum 27704 was
> detected.

The wording there could possibly be misinterpreted as the firmware
actively having to do something to the hardware prior to handing it off
to Linux, as opposed to merely supplying a correct FDT or IORT table,
but I'm not sure it matters all that much, and the patch itself is fine:

Reviewed-by: Robin Murphy <[email protected]>

Thanks,
Robin.

> Signed-off-by: Robert Richter <[email protected]>
> ---
> drivers/iommu/arm-smmu.c | 1 +
> 1 file changed, 1 insertion(+)
>
> diff --git a/drivers/iommu/arm-smmu.c b/drivers/iommu/arm-smmu.c
> index abf6496843a6..c88bf8deb958 100644
> --- a/drivers/iommu/arm-smmu.c
> +++ b/drivers/iommu/arm-smmu.c
> @@ -1887,6 +1887,7 @@ static int arm_smmu_device_cfg_probe(struct arm_smmu_device *smmu)
> atomic_add_return(smmu->num_context_banks,
> &cavium_smmu_context_count);
> smmu->cavium_id_base -= smmu->num_context_banks;
> + dev_notice(smmu->dev, "\tenabling workaround for Cavium erratum 27704\n");
> }
>
> /* ID2 */
>