The goal is to avoid anyone entering the same information twice, so the work order in SAP or Maximo should be the starting point that the permit and procedure build on. Equipment, location and job details can come from the work order, and status updates and completion information can go back to it.
Each system should own what it is best at, with the CMMS owning work orders and maintenance history and the field tool owning permits and procedure execution. Agreeing on that split and on the few fields that move between them is usually more important than the technical details of the integration.