ARM_SMMU_CB_FAR
iova = readq_relaxed(cb_base + ARM_SMMU_CB_FAR);
info->far = arm_smmu_cb_readq(smmu, cfg->cbndx, ARM_SMMU_CB_FAR);
cfi->iova = arm_smmu_cb_readq(smmu, idx, ARM_SMMU_CB_FAR);
iova = iommu_readq(ctx, ARM_SMMU_CB_FAR);
iommu_writel(ctx, ARM_SMMU_CB_FAR, 0);