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

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Date:   Mon, 3 Apr 2017 23:16:33 +0530
From:   Sunil Kovvuri <sunil.kovvuri@...il.com>
To:     Will Deacon <will.deacon@....com>,
        Robin Murphy <robin.murphy@....com>
Cc:     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 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 ?

Thanks,
Sunil.