Dose anyone tried DFFRAM or openRAM in gf180? If so, could I get the access time of the read/write operation of generated macros?

There is no OpenRAM for GF180 (that I'm aware of), but the GF180 PDK came with SRAM blocks from GF that can be trusted. There are DFFRAM blocks used in the management SoC that are part of the caravel-GF repository.