Existing conversion tools for HL7v2, v3, ... to FHIR?

Not looked at HL7v3/CDA.

I use Apache Camel plus HAPI HL7 v2+FHIR to do the conversions. It is not automated but HL7 have produced mapping guidance v2-to-FHIR Map Inventory - جداول بيانات Google
I’ve used this.