Re: [PATCH v3 11/24] iommu/io-pgtable-arm-v7s: Quad lvl1 pgtable for MediaTek

Robin Murphy
2020-10-23T14:10:43Z

On 2020-09-30 08:06, Yong Wu wrote:
> The standard input iova bits is 32. MediaTek quad the lvl1 pagetable
> (4 * lvl1). No change for lvl2 pagetable. Then the iova bits can reach
> 34bit.
>
> Signed-off-by: Yong Wu <yong.wu@mediatek.com>
> ---
> drivers/iommu/io-pgtable-arm-v7s.c | 13 ++++++++++---
> drivers/iommu/mtk_iommu.c | 2 +-
> 2 files changed, 11 insertions(+), 4 deletions(-)
>
> diff --git a/drivers/iommu/io-pgtable-arm-v7s.c b/drivers/iommu/io-pgtable-arm-v7s.c
> index 8362fdf76657..306bae2755ed 100644
> --- a/drivers/iommu/io-pgtable-arm-v7s.c
> +++ b/drivers/iommu/io-pgtable-arm-v7s.c
> @@ -50,10 +50,17 @@
> */
> #define ARM_V7S_ADDR_BITS 32
> #define _ARM_V7S_LVL_BITS(lvl) (16 - (lvl) * 4)
> +/* MediaTek: totally 34bits, 14bits at lvl1 and 8bits at lvl2. */
> +#define _ARM_V7S_LVL_BITS_MTK(lvl) (20 - (lvl) * 6)

This should defined in terms of both lvl and cfg->ias. The formula here
is nothing more than a disgusting trick I made up since a linear
interpolation happened to fit the required numbers. That said, all of
these bits pretending that short-descriptor is a well-defined recursive
format only served to allow the rest of the code to look more like the
LPAE code - IIRC they've already diverged a fair bit since then, so
frankly a lot of this could stand to be unpicked and made considerably
clearer by simply accepting that level 1 and level 2 are different from
each other.

Robin.

> #define ARM_V7S_LVL_SHIFT(lvl) (ARM_V7S_ADDR_BITS - (4 + 8 * (lvl)))
> #define ARM_V7S_TABLE_SHIFT 10
>
> -#define ARM_V7S_PTES_PER_LVL(lvl, cfg) (1 << _ARM_V7S_LVL_BITS(lvl))
> +#define ARM_V7S_PTES_PER_LVL(lvl, cfg) ({ \
> + int _lvl = lvl; \
> + !arm_v7s_is_mtk_enabled(cfg) ? \
> + (1 << _ARM_V7S_LVL_BITS(_lvl)) : (1 << _ARM_V7S_LVL_BITS_MTK(_lvl));\
> +})
> +
> #define ARM_V7S_TABLE_SIZE(lvl, cfg) \
> (ARM_V7S_PTES_PER_LVL(lvl, cfg) * sizeof(arm_v7s_iopte))
>
> @@ -63,7 +70,7 @@
> #define _ARM_V7S_IDX_MASK(lvl, cfg) (ARM_V7S_PTES_PER_LVL(lvl, cfg) - 1)
> #define ARM_V7S_LVL_IDX(addr, lvl, cfg) ({ \
> int _l = lvl; \
> - ((u32)(addr) >> ARM_V7S_LVL_SHIFT(_l)) & _ARM_V7S_IDX_MASK(_l, cfg); \
> + ((addr) >> ARM_V7S_LVL_SHIFT(_l)) & _ARM_V7S_IDX_MASK(_l, cfg); \
> })
>
> /*
> @@ -755,7 +762,7 @@ static struct io_pgtable *arm_v7s_alloc_pgtable(struct io_pgtable_cfg *cfg,
> {
> struct arm_v7s_io_pgtable *data;
>
> - if (cfg->ias > ARM_V7S_ADDR_BITS)
> + if (cfg->ias > (arm_v7s_is_mtk_enabled(cfg) ? 34 : ARM_V7S_ADDR_BITS))
> return NULL;
>
> if (cfg->oas > (arm_v7s_is_mtk_enabled(cfg) ? 35 : ARM_V7S_ADDR_BITS))
> diff --git a/drivers/iommu/mtk_iommu.c b/drivers/iommu/mtk_iommu.c
> index f6a2e3eb59d2..6e85c9976a33 100644
> --- a/drivers/iommu/mtk_iommu.c
> +++ b/drivers/iommu/mtk_iommu.c
> @@ -316,7 +316,7 @@ static int mtk_iommu_domain_finalise(struct mtk_iommu_domain *dom)
> IO_PGTABLE_QUIRK_TLBI_ON_MAP |
> IO_PGTABLE_QUIRK_ARM_MTK_EXT,
> .pgsize_bitmap = mtk_iommu_ops.pgsize_bitmap,
> - .ias = 32,
> + .ias = 34,
> .oas = 35,
> .tlb = &mtk_iommu_flush_ops,
> .iommu_dev = data->dev,