can dma_alloc_coherent & pci_alloc_consistent return a 64bit bus address ?

hi all:
can dma_alloc_coherent & pci_alloc_consistent return a 64bit bus address ?

shall we disable SMMU to achieve this?

when SMMU disabled, can we just feed the hardware with " virt_to_phys( __get_free_pages() )" ?

and will virt_to_phys( __get_free_pages() ) be a 64bit physical address ( also bus address in value, since SMMU disabled) ?

Discussed in https://devtalk.nvidia.com/default/topic/1026334/jetson-tx2/pcie-dma-problem-between-tx2-amp-fpga/post/5220805/#5220805