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SubjectRe: [PATCH v2 04/14] iommu/io-pgtable-arm-v7s: Add paddr_to_iopte and iopte_to_paddr helpers
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Hi Robin,

Thanks very much for your review.

On Thu, 2018-11-01 at 16:34 +0000, Robin Murphy wrote:
> [ apologies if anyone gets this twice, looks like our email's eaten
> itself again... ]
>
> On 24/09/2018 09:58, Yong Wu wrote:
> > Add two helper functions: paddr_to_iopte and iopte_to_paddr.
>
> Nice and tidy! (although it will need rebasing now, but I think that's
> just context conflicts)
>
> > Signed-off-by: Yong Wu <yong.wu@mediatek.com>
> > ---
> > drivers/iommu/io-pgtable-arm-v7s.c | 45 ++++++++++++++++++++++++++++----------
> > 1 file changed, 33 insertions(+), 12 deletions(-)
> >
> > diff --git a/drivers/iommu/io-pgtable-arm-v7s.c b/drivers/iommu/io-pgtable-arm-v7s.c
> > index b5948ba..fa3b9ec 100644
> > --- a/drivers/iommu/io-pgtable-arm-v7s.c
> > +++ b/drivers/iommu/io-pgtable-arm-v7s.c
> > @@ -173,18 +173,38 @@ struct arm_v7s_io_pgtable {
> > spinlock_t split_lock;
> > };
> >
> > +static bool arm_v7s_pte_is_cont(arm_v7s_iopte pte, int lvl);
> > +
> > static dma_addr_t __arm_v7s_dma_addr(void *pages)
> > {
> > return (dma_addr_t)virt_to_phys(pages);
> > }
> >
> > -static arm_v7s_iopte *iopte_deref(arm_v7s_iopte pte, int lvl)
> > +static arm_v7s_iopte paddr_to_iopte(phys_addr_t paddr, int lvl,
> > + struct arm_v7s_io_pgtable *data)
>
> Nit: it seems to work out a little cleaner if we pass the io_pgtable_cfg
> to these helpers directly, rather than re-deriving it from data each time.

I will use "io_pgtable_cfg" instead of "arm_v7s_io_pgtable" in the next
version. This is a minor change and I will keep your R-b.

>
> Otherwise, though,
>
> Reviewed-by: Robin Murphy <robin.murphy@arm.com>
>
> > {
> > + return paddr & ARM_V7S_LVL_MASK(lvl);
> > +}
> > +
> > +static phys_addr_t iopte_to_paddr(arm_v7s_iopte pte, int lvl,
> > + struct arm_v7s_io_pgtable *data)
> > +{
> > + arm_v7s_iopte mask;
> > +
> > if (ARM_V7S_PTE_IS_TABLE(pte, lvl))
> > - pte &= ARM_V7S_TABLE_MASK;
> > + mask = ARM_V7S_TABLE_MASK;
> > + else if (arm_v7s_pte_is_cont(pte, lvl))
> > + mask = ARM_V7S_LVL_MASK(lvl) * ARM_V7S_CONT_PAGES;
> > else
> > - pte &= ARM_V7S_LVL_MASK(lvl);
> > - return phys_to_virt(pte);
> > + mask = ARM_V7S_LVL_MASK(lvl);
> > +
> > + return pte & mask;
> > +}
> > +
> > +static arm_v7s_iopte *iopte_deref(arm_v7s_iopte pte, int lvl,
> > + struct arm_v7s_io_pgtable *data)
> > +{
> > + return phys_to_virt(iopte_to_paddr(pte, lvl, data));
> > }
> >
> > static void *__arm_v7s_alloc_table(int lvl, gfp_t gfp,
> > @@ -396,7 +416,7 @@ static int arm_v7s_init_pte(struct arm_v7s_io_pgtable *data,
> > if (num_entries > 1)
> > pte = arm_v7s_pte_to_cont(pte, lvl);
> >
> > - pte |= paddr & ARM_V7S_LVL_MASK(lvl);
> > + pte |= paddr_to_iopte(paddr, lvl, data);
> >
> > __arm_v7s_set_pte(ptep, pte, num_entries, cfg);
> > return 0;
> > @@ -462,7 +482,7 @@ static int __arm_v7s_map(struct arm_v7s_io_pgtable *data, unsigned long iova,
> > }
> >
> > if (ARM_V7S_PTE_IS_TABLE(pte, lvl)) {
> > - cptep = iopte_deref(pte, lvl);
> > + cptep = iopte_deref(pte, lvl, data);
> > } else if (pte) {
> > /* We require an unmap first */
> > WARN_ON(!selftest_running);
> > @@ -512,7 +532,8 @@ static void arm_v7s_free_pgtable(struct io_pgtable *iop)
> > arm_v7s_iopte pte = data->pgd[i];
> >
> > if (ARM_V7S_PTE_IS_TABLE(pte, 1))
> > - __arm_v7s_free_table(iopte_deref(pte, 1), 2, data);
> > + __arm_v7s_free_table(iopte_deref(pte, 1, data),
> > + 2, data);
> > }
> > __arm_v7s_free_table(data->pgd, 1, data);
> > kmem_cache_destroy(data->l2_tables);
> > @@ -582,7 +603,7 @@ static size_t arm_v7s_split_blk_unmap(struct arm_v7s_io_pgtable *data,
> > if (!ARM_V7S_PTE_IS_TABLE(pte, 1))
> > return 0;
> >
> > - tablep = iopte_deref(pte, 1);
> > + tablep = iopte_deref(pte, 1, data);
> > return __arm_v7s_unmap(data, iova, size, 2, tablep);
> > }
> >
> > @@ -640,7 +661,7 @@ static size_t __arm_v7s_unmap(struct arm_v7s_io_pgtable *data,
> > io_pgtable_tlb_add_flush(iop, iova, blk_size,
> > ARM_V7S_BLOCK_SIZE(lvl + 1), false);
> > io_pgtable_tlb_sync(iop);
> > - ptep = iopte_deref(pte[i], lvl);
> > + ptep = iopte_deref(pte[i], lvl, data);
> > __arm_v7s_free_table(ptep, lvl + 1, data);
> > } else {
> > io_pgtable_tlb_add_flush(iop, iova, blk_size,
> > @@ -658,7 +679,7 @@ static size_t __arm_v7s_unmap(struct arm_v7s_io_pgtable *data,
> > }
> >
> > /* Keep on walkin' */
> > - ptep = iopte_deref(pte[0], lvl);
> > + ptep = iopte_deref(pte[0], lvl, data);
> > return __arm_v7s_unmap(data, iova, size, lvl + 1, ptep);
> > }
> >
> > @@ -684,7 +705,7 @@ static phys_addr_t arm_v7s_iova_to_phys(struct io_pgtable_ops *ops,
> > do {
> > ptep += ARM_V7S_LVL_IDX(iova, ++lvl);
> > pte = READ_ONCE(*ptep);
> > - ptep = iopte_deref(pte, lvl);
> > + ptep = iopte_deref(pte, lvl, data);
> > } while (ARM_V7S_PTE_IS_TABLE(pte, lvl));
> >
> > if (!ARM_V7S_PTE_IS_VALID(pte))
> > @@ -693,7 +714,7 @@ static phys_addr_t arm_v7s_iova_to_phys(struct io_pgtable_ops *ops,
> > mask = ARM_V7S_LVL_MASK(lvl);
> > if (arm_v7s_pte_is_cont(pte, lvl))
> > mask *= ARM_V7S_CONT_PAGES;
> > - return (pte & mask) | (iova & ~mask);
> > + return iopte_to_paddr(pte, lvl, data) | (iova & ~mask);
> > }
> >
> > static struct io_pgtable *arm_v7s_alloc_pgtable(struct io_pgtable_cfg *cfg,
> >
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