Re: [PATCH 1/3] iommu/arm-smmu: Move to bitmap for arm_smmu_domain atrributes

[Vivek Gautam]

On Mon, Jan 21, 2019 at 7:23 PM Robin Murphy <robin.murphy@xxxxxxx> wrote:
>
> On 21/01/2019 05:53, Vivek Gautam wrote:
> > A number of arm_smmu_domain's attributes can be assigned based
> > on the iommu domains's attributes. These local attributes better
> > be managed by a bitmap.
> > So remove boolean flags and move to a 32-bit bitmap, and enable
> > each bits separtely.
> >
> > Signed-off-by: Vivek Gautam <vivek.gautam@xxxxxxxxxxxxxx>
> > ---
> >   drivers/iommu/arm-smmu.c | 10 ++++++----
> >   1 file changed, 6 insertions(+), 4 deletions(-)
> >
> > diff --git a/drivers/iommu/arm-smmu.c b/drivers/iommu/arm-smmu.c
> > index 7ebbcf1b2eb3..52b300dfc096 100644
> > --- a/drivers/iommu/arm-smmu.c
> > +++ b/drivers/iommu/arm-smmu.c
> > @@ -257,10 +257,11 @@ struct arm_smmu_domain {
> >       const struct iommu_gather_ops   *tlb_ops;
> >       struct arm_smmu_cfg             cfg;
> >       enum arm_smmu_domain_stage      stage;
> > -     bool                            non_strict;
> >       struct mutex                    init_mutex; /* Protects smmu pointer */
> >       spinlock_t                      cb_lock; /* Serialises ATS1* ops and TLB syncs */
> >       struct iommu_domain             domain;
> > +#define ARM_SMMU_DOMAIN_ATTR_NON_STRICT      BIT(0)
> > +     unsigned int                    attr;
> >   };
> >
> >   struct arm_smmu_option_prop {
> > @@ -901,7 +902,7 @@ static int arm_smmu_init_domain_context(struct iommu_domain *domain,
> >       if (smmu->features & ARM_SMMU_FEAT_COHERENT_WALK)
> >               pgtbl_cfg.quirks = IO_PGTABLE_QUIRK_NO_DMA;
> >
> > -     if (smmu_domain->non_strict)
> > +     if (smmu_domain->attr & ARM_SMMU_DOMAIN_ATTR_NON_STRICT)
> >               pgtbl_cfg.quirks |= IO_PGTABLE_QUIRK_NON_STRICT;
> >
> >       /* Non coherent page table mappings only for Stage-1 */
> > @@ -1598,7 +1599,8 @@ static int arm_smmu_domain_get_attr(struct iommu_domain *domain,
> >       case IOMMU_DOMAIN_DMA:
> >               switch (attr) {
> >               case DOMAIN_ATTR_DMA_USE_FLUSH_QUEUE:
> > -                     *(int *)data = smmu_domain->non_strict;
> > +                     *(int *)data = !!(smmu_domain->attr &
> > +                                       ARM_SMMU_DOMAIN_ATTR_NON_STRICT);
> >                       return 0;
> >               default:
> >                       return -ENODEV;
> > @@ -1638,7 +1640,7 @@ static int arm_smmu_domain_set_attr(struct iommu_domain *domain,
> >       case IOMMU_DOMAIN_DMA:
> >               switch (attr) {
> >               case DOMAIN_ATTR_DMA_USE_FLUSH_QUEUE:
> > -                     smmu_domain->non_strict = *(int *)data;
> > +                     smmu_domain->attr |= ARM_SMMU_DOMAIN_ATTR_NON_STRICT;
>
> But what if *data == 0?

Right, a check for data here also similar to what we are doing for
QCOM_SYS_CACHE [1].

[1] https://lore.kernel.org/patchwork/patch/1033796/

Regards
Vivek

>
> Robin.
>
> >                       break;
> >               default:
> >                       ret = -ENODEV;
> >
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