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. Will
