Re: [PATCH v7 1/5] iommu/arm-smmu: re-enable context caching in smmu reset operation

[Bibek Kumar Patro]

On 1/10/2024 4:30 PM, Konrad Dybcio wrote:
> On 1/9/24 12:42, Bibek Kumar Patro wrote:
> > Default MMU-500 reset operation disables context caching in
> > prefetch buffer. It is however expected for context banks using
> > the ACTLR register to retain their prefetch value during reset
> > and runtime suspend.
> >
> > Replace default MMU-500 reset operation with Qualcomm specific reset
> > operation which envelope the default reset operation and re-enables
> > context caching in prefetch buffer for Qualcomm SoCs.
> >
> > Signed-off-by: Bibek Kumar Patro <quic_bibekkum@xxxxxxxxxxx>
> > ---
> >   drivers/iommu/arm/arm-smmu/arm-smmu-qcom.c | 37 ++++++++++++++++++++--
> >   1 file changed, 34 insertions(+), 3 deletions(-)
> >
> > diff --git a/drivers/iommu/arm/arm-smmu/arm-smmu-qcom.c 
> > b/drivers/iommu/arm/arm-smmu/arm-smmu-qcom.c
> > index 549ae4dba3a6..000e207346af 100644
> > --- a/drivers/iommu/arm/arm-smmu/arm-smmu-qcom.c
> > +++ b/drivers/iommu/arm/arm-smmu/arm-smmu-qcom.c
> > @@ -14,6 +14,16 @@
> >
> >   #define QCOM_DUMMY_VAL    -1
> >
> > +/*
> > + * SMMU-500 TRM defines BIT(0) as CMTLB (Enable context caching in the
> > + * macro TLB) and BIT(1) as CPRE (Enable context caching in the prefetch
> > + * buffer). The remaining bits are implementation defined and vary 
> > across
> > + * SoCs.
> > + */
> > +
> > +#define CPRE            (1 << 1)
> > +#define CMTLB            (1 << 0)
> > +
> >   static struct qcom_smmu *to_qcom_smmu(struct arm_smmu_device *smmu)
> >   {
> >       return container_of(smmu, struct qcom_smmu, smmu);
> > @@ -376,11 +386,32 @@ static int qcom_smmu_def_domain_type(struct 
> > device *dev)
> >       return match ? IOMMU_DOMAIN_IDENTITY : 0;
> >   }
> >
> > +static int qcom_smmu500_reset(struct arm_smmu_device *smmu)
> > +{
> > +    int ret;
> > +    u32 val;
> > +    int i;
> > +
> > +    ret = arm_mmu500_reset(smmu);
> > +
> > +    if (ret)
> Weird empty line.. Please remove it in the next revision since you're
> already going to send a new one..
>
> Reviewed-by: Konrad Dybcio <konrad.dybcio@xxxxxxxxxx>

Ack, thanks for pointing this out.
Will remove this while sending out the new patch.

Thanks & regards,
Bibek

> Konrad