Here is the link to the roadmap for Mbed TLS and PSA Crypto in the coming quarters. https://developer.trustedfirmware.org/w/mbed-tls/roadmap/
If you are interested in collaborating on any of the roadmap features or other features in the project, please let your interest known via. the mailing lists.
Note that the expected quarter when a feature will be completed is based on very rough estimates of the effort involved and therefore might change. Roadmap will be reviewed and updated at the start of every quarter depending on progress made in previous quarter.
Thanks, Shebu (Mbed TLS, PSA Crypto Technology Manager, Arm)