Re: [PATCH 1/1] iommu/arm-smmu: Log CBFRSYNRA register on context fault

[Vivek Gautam]

On Fri, Apr 19, 2019 at 5:55 AM Bjorn Andersson
<bjorn.andersson@xxxxxxxxxx> wrote:
>
> On Mon 15 Apr 10:37 PDT 2019, Vivek Gautam wrote:
>
> > Bits[15:0] in CBFRSYNRA register contain information about
> > StreamID of the incoming transaction that generated the
> > fault. Dump CBFRSYNRA register to get this info.
> > This is specially useful in a distributed SMMU architecture
> > where multiple masters are connected to the SMMU.
> > SID information helps to quickly identify the faulting
> > master device.
> >
> > Signed-off-by: Vivek Gautam <vivek.gautam@xxxxxxxxxxxxxx>
> > ---
> >
> > V1 of the patch available @
> > https://lore.kernel.org/patchwork/patch/1061615/
> >
> > Changes from v1:
> >  - Dump the raw register value of CBFRSYNRA register in the
> >    context fault log rather than extracting the SID inforamtion
> >    and dumping that.
> >
> >  drivers/iommu/arm-smmu-regs.h | 2 ++
> >  drivers/iommu/arm-smmu.c      | 8 ++++++--
> >  2 files changed, 8 insertions(+), 2 deletions(-)
> >
> > diff --git a/drivers/iommu/arm-smmu-regs.h b/drivers/iommu/arm-smmu-regs.h
> > index a1226e4ab5f8..e9132a926761 100644
> > --- a/drivers/iommu/arm-smmu-regs.h
> > +++ b/drivers/iommu/arm-smmu-regs.h
> > @@ -147,6 +147,8 @@ enum arm_smmu_s2cr_privcfg {
> >  #define CBAR_IRPTNDX_SHIFT           24
> >  #define CBAR_IRPTNDX_MASK            0xff
> >
> > +#define ARM_SMMU_GR1_CBFRSYNRA(n)    (0x400 + ((n) << 2))
> > +
> >  #define ARM_SMMU_GR1_CBA2R(n)                (0x800 + ((n) << 2))
> >  #define CBA2R_RW64_32BIT             (0 << 0)
> >  #define CBA2R_RW64_64BIT             (1 << 0)
> > diff --git a/drivers/iommu/arm-smmu.c b/drivers/iommu/arm-smmu.c
> > index 045d93884164..a4773e8c6b0e 100644
> > --- a/drivers/iommu/arm-smmu.c
> > +++ b/drivers/iommu/arm-smmu.c
> > @@ -575,7 +575,9 @@ static irqreturn_t arm_smmu_context_fault(int irq, void *dev)
> >       struct arm_smmu_domain *smmu_domain = to_smmu_domain(domain);
> >       struct arm_smmu_cfg *cfg = &smmu_domain->cfg;
> >       struct arm_smmu_device *smmu = smmu_domain->smmu;
> > +     void __iomem *gr1_base = ARM_SMMU_GR1(smmu);
> >       void __iomem *cb_base;
> > +     u32 cbfrsynra;
> >
> >       cb_base = ARM_SMMU_CB(smmu, cfg->cbndx);
> >       fsr = readl_relaxed(cb_base + ARM_SMMU_CB_FSR);
> > @@ -585,10 +587,12 @@ static irqreturn_t arm_smmu_context_fault(int irq, void *dev)
> >
> >       fsynr = readl_relaxed(cb_base + ARM_SMMU_CB_FSYNR0);
> >       iova = readq_relaxed(cb_base + ARM_SMMU_CB_FAR);
> > +     cbfrsynra = readl_relaxed(gr1_base +
> > +                               ARM_SMMU_GR1_CBFRSYNRA(cfg->cbndx));
>
> The 80 char limit is more like a guideline anyways...please don't wrap
> this.
>
> >
> >       dev_err_ratelimited(smmu->dev,
> > -     "Unhandled context fault: fsr=0x%x, iova=0x%08lx, fsynr=0x%x, cb=%d\n",
> > -                         fsr, iova, fsynr, cfg->cbndx);
> > +     "Unhandled context fault: fsr=0x%x, iova=0x%08lx, fsynr=0x%x, cbfrsynra = 0x%x, cb=%d\n",
>
> Drop the spaces around '='.
>
> With those addressed, you have my
>
> Reviewed-by: Bjorn Andersson <bjorn.andersson@xxxxxxxxxx>

Thanks for the review Bjorn. Will address above comments and respin.

Best regards
Vivek

>
> Regards,
> Bjorn
>
> > +                         fsr, iova, fsynr, cbfrsynra, cfg->cbndx);
> >
> >       writel(fsr, cb_base + ARM_SMMU_CB_FSR);
> >       return IRQ_HANDLED;
> > --
> > QUALCOMM INDIA, on behalf of Qualcomm Innovation Center, Inc. is a member
> > of Code Aurora Forum, hosted by The Linux Foundation
> >
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