linux-kernel - Re: [PATCH] iommu/arm-smmu: Fix 16bit ASID configuration

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Message-ID: <20170403174911.GJ5706@arm.com>
Date:   Mon, 3 Apr 2017 18:49:11 +0100
From:   Will Deacon <will.deacon@....com>
To:     Sunil Kovvuri <sunil.kovvuri@...il.com>
Cc:     Robin Murphy <robin.murphy@....com>,
        iommu@...ts.linux-foundation.org,
        LAKML <linux-arm-kernel@...ts.infradead.org>,
        LKML <linux-kernel@...r.kernel.org>,
        Sunil Goutham <sgoutham@...ium.com>
Subject: Re: [PATCH] iommu/arm-smmu: Fix 16bit ASID configuration

On Mon, Apr 03, 2017 at 11:16:33PM +0530, Sunil Kovvuri wrote:
> On Tue, Mar 28, 2017 at 4:11 PM,  <sunil.kovvuri@...il.com> wrote:
> > From: Sunil Goutham <sgoutham@...ium.com>
> >
> > 16bit ASID should be enabled before initializing TTBR0/1,
> > otherwise only LSB 8bit ASID will be considered. Hence
> > moving configuration of TTBCR register ahead of TTBR0/1
> > while initializing context bank.
> >
> > Signed-off-by: Sunil Goutham <sgoutham@...ium.com>
> > ---
> >  drivers/iommu/arm-smmu.c | 41 ++++++++++++++++++++++-------------------
> >  1 file changed, 22 insertions(+), 19 deletions(-)
> >
> > diff --git a/drivers/iommu/arm-smmu.c b/drivers/iommu/arm-smmu.c
> > index 9b33700..2845d73 100644
> > --- a/drivers/iommu/arm-smmu.c
> > +++ b/drivers/iommu/arm-smmu.c
> > @@ -758,6 +758,28 @@ static void arm_smmu_init_context_bank(struct arm_smmu_domain *smmu_domain,
> >         }
> >         writel_relaxed(reg, gr1_base + ARM_SMMU_GR1_CBAR(cfg->cbndx));
> >
> > +       /* TTBCR */
> > +       if (stage1) {
> > +               if (cfg->fmt == ARM_SMMU_CTX_FMT_AARCH32_S) {
> > +                       reg = pgtbl_cfg->arm_v7s_cfg.tcr;
> > +                       reg2 = 0;
> > +               } else {
> > +                       reg = pgtbl_cfg->arm_lpae_s1_cfg.tcr;
> > +                       reg2 = pgtbl_cfg->arm_lpae_s1_cfg.tcr >> 32;
> > +                       reg2 |= TTBCR2_SEP_UPSTREAM;
> > +                       /* 16bit ASID should be enabled before write to TTBR,
> > +                        * otherwise only LSB 8bit will be considered.
> > +                        */
> > +                       if (cfg->fmt == ARM_SMMU_CTX_FMT_AARCH64)
> > +                               reg2 |= TTBCR2_AS;
> > +               }
> > +               if (smmu->version > ARM_SMMU_V1)
> > +                       writel_relaxed(reg2, cb_base + ARM_SMMU_CB_TTBCR2);
> > +       } else {
> > +               reg = pgtbl_cfg->arm_lpae_s2_cfg.vtcr;
> > +       }
> > +       writel_relaxed(reg, cb_base + ARM_SMMU_CB_TTBCR);
> > +
> >         /* TTBRs */
> >         if (stage1) {
> >                 u16 asid = ARM_SMMU_CB_ASID(smmu, cfg);
> > @@ -781,25 +803,6 @@ static void arm_smmu_init_context_bank(struct arm_smmu_domain *smmu_domain,
> >                 writeq_relaxed(reg64, cb_base + ARM_SMMU_CB_TTBR0);
> >         }
> >
> > -       /* TTBCR */
> > -       if (stage1) {
> > -               if (cfg->fmt == ARM_SMMU_CTX_FMT_AARCH32_S) {
> > -                       reg = pgtbl_cfg->arm_v7s_cfg.tcr;
> > -                       reg2 = 0;
> > -               } else {
> > -                       reg = pgtbl_cfg->arm_lpae_s1_cfg.tcr;
> > -                       reg2 = pgtbl_cfg->arm_lpae_s1_cfg.tcr >> 32;
> > -                       reg2 |= TTBCR2_SEP_UPSTREAM;
> > -                       if (cfg->fmt == ARM_SMMU_CTX_FMT_AARCH64)
> > -                               reg2 |= TTBCR2_AS;
> > -               }
> > -               if (smmu->version > ARM_SMMU_V1)
> > -                       writel_relaxed(reg2, cb_base + ARM_SMMU_CB_TTBCR2);
> > -       } else {
> > -               reg = pgtbl_cfg->arm_lpae_s2_cfg.vtcr;
> > -       }
> > -       writel_relaxed(reg, cb_base + ARM_SMMU_CB_TTBCR);
> > -
> >         /* MAIRs (stage-1 only) */
> >         if (stage1) {
> >                 if (cfg->fmt == ARM_SMMU_CTX_FMT_AARCH32_S) {
> > --
> > 2.7.4
> >
> 
> Any comments or feedback on this patch ?

I've picked it up.

Will