ecmd_submit_sync
int ecmd_submit_sync(struct intel_iommu *iommu, u8 ecmd, u64 oa, u64 ob);
ecmd_submit_sync(iommu, DMA_ECMD_ENABLE, hwc->idx, 0);
ecmd_submit_sync(iommu, DMA_ECMD_DISABLE, hwc->idx, 0);
ecmd_submit_sync(iommu, DMA_ECMD_UNFREEZE, 0, 0);
ecmd_submit_sync(iommu, DMA_ECMD_FREEZE, 0, 0);