> -----Original Message-----
> From: Will Deacon [mailto:[email protected]]
> Sent: 04 April 2019 16:47
> To: Shameerali Kolothum Thodi <[email protected]>
> Cc: [email protected]; [email protected];
> [email protected]; [email protected];
> [email protected]; Guohanjun (Hanjun Guo) <[email protected]>;
> John Garry <[email protected]>; [email protected];
> [email protected]; [email protected]; [email protected];
> [email protected]; [email protected]; Linuxarm
> <[email protected]>; [email protected]
> Subject: Re: [PATCH v7 4/4] perf/smmuv3: Enable HiSilicon Erratum 162001800
> quirk
>
> On Tue, Mar 26, 2019 at 03:17:53PM +0000, 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 <[email protected]>
> > Reviewed-by: Hanjun Guo <[email protected]>
> > Reviewed-by: Robin Murphy <[email protected]>
> > ---
> > 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(-)
> >
> > diff --git a/drivers/acpi/arm64/iort.c b/drivers/acpi/arm64/iort.c
> > index e2c9b26..4dc68de 100644
> > --- a/drivers/acpi/arm64/iort.c
> > +++ b/drivers/acpi/arm64/iort.c
> > @@ -1366,9 +1366,23 @@ static void __init
> arm_smmu_v3_pmcg_init_resources(struct resource *res,
> > ACPI_EDGE_SENSITIVE, &res[2]);
> > }
> >
> > +static struct acpi_platform_list pmcg_plat_info[] __initdata = {
> > + /* HiSilicon Hip08 Platform */
> > + {"HISI ", "HIP08 ", 0, ACPI_SIG_IORT, greater_than_or_equal, 0,
>
> Passing integer constant 0 for the reason feels wrong to me. I'm going to
> change it to "Erratum #162001800" and also add an entry to
> silicon-errata.txt.
>
> Please shout if that's not ok.
Thanks Will for taking a look at this series. The proposed changes are fine to
me.
Shameer
