> Does exists an ecquivalent NetBSD function of the bus_dma_tag_create()
> FreeBSD function?

You can use "pa_dmat" member of "struct pci_attach_args" on NetBSD,
instead of bus_dma_tag_create().
For example, please look at NetBSD's sys/dev/pci/ahc_pci.c for detail.

BTW, every occurrence of vtophys() should be converted to use bus_dma
function on NetBSD, but current FreeBSD's advansys driver doesn't seem 
to follow this manner. (and interface of bus_dmamap_load() is different
between NetBSD and FreeBSD, as currently discussed on this mailing-list.)
--
soda