Re: [PATCH v6 4/4] perf/smmuv3_pmu: Enable HiSilicon Erratum 162001800 quirk

From: Hanjun Guo
Date: Thu Feb 14 2019 - 02:30:12 EST


On 2019/2/4 20:13, Shameer Kolothum wrote:
> HiSilicon erratum 162001800 describes the limitation of
> SMMUv3 PMCG implementation on HiSilicon Hip08 platforms.
>
> On these platforms, the PMCG event counter registers
> (SMMU_PMCG_EVCNTRn) are read only and as a result it
> is not possible to set the initial counter period value
> on event monitor start.
>
> To work around this, the current value of the counter
> is read and used for delta calculations. OEM information
> from ACPI header is used to identify the affected hardware
> platforms.
>
> Signed-off-by: Shameer Kolothum <shameerali.kolothum.thodi@xxxxxxxxxx>
> ---
> drivers/acpi/arm64/iort.c | 16 ++++++++++++++-
> drivers/perf/arm_smmuv3_pmu.c | 48 ++++++++++++++++++++++++++++++++++++-------
> include/linux/acpi_iort.h | 1 +
> 3 files changed, 57 insertions(+), 8 deletions(-)

For this patch,

Reviewed-by: Hanjun Guo <hanjun.guo@xxxxxxxxxx>

Thanks
Hanjun