[PATCH 01/19] iommu/arm-smmu-v3: Add a type for the STE

[Will Deacon]

On Tue, Oct 10, 2023 at 09:33:07PM -0300, Jason Gunthorpe wrote:
> Instead of passing a naked __le16 * around to represent a STE wrap it in a
> "struct arm_smmu_ste" with an array of the correct size. This makes it
> much clearer which functions will comprise the "STE API".
> 
> Signed-off-by: Jason Gunthorpe <jgg at nvidia.com>
> ---
>  drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.c | 54 ++++++++++-----------
>  drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.h |  7 ++-
>  2 files changed, 32 insertions(+), 29 deletions(-)

[...]

> @@ -2209,26 +2210,22 @@ static int arm_smmu_domain_finalise(struct iommu_domain *domain)
>  	return 0;
>  }
>  
> -static __le64 *arm_smmu_get_step_for_sid(struct arm_smmu_device *smmu, u32 sid)
> +static struct arm_smmu_ste *
> +arm_smmu_get_step_for_sid(struct arm_smmu_device *smmu, u32 sid)
>  {
> -	__le64 *step;
>  	struct arm_smmu_strtab_cfg *cfg = &smmu->strtab_cfg;
>  
>  	if (smmu->features & ARM_SMMU_FEAT_2_LVL_STRTAB) {
> -		struct arm_smmu_strtab_l1_desc *l1_desc;
>  		int idx;
>  
>  		/* Two-level walk */
>  		idx = (sid >> STRTAB_SPLIT) * STRTAB_L1_DESC_DWORDS;
> -		l1_desc = &cfg->l1_desc[idx];
> -		idx = (sid & ((1 << STRTAB_SPLIT) - 1)) * STRTAB_STE_DWORDS;
> -		step = &l1_desc->l2ptr[idx];
> +		return &cfg->l1_desc[idx].l2ptr[sid & ((1 << STRTAB_SPLIT) - 1)];
>  	} else {
>  		/* Simple linear lookup */
> -		step = &cfg->strtab[sid * STRTAB_STE_DWORDS];
> +		return (struct arm_smmu_ste *)&cfg
> +			       ->strtab[sid * STRTAB_STE_DWORDS];

Why not change the type of 'struct arm_smmu_strtab_cfg::strtab' at the same
time?

Will