A group of developers going by the name of PSP Code, have created an API for PSP game developers called PSPGE.
PSPGE stands for PlayStation Portable Game Environment and lets you create PSP games.
Everything is quite new with this team and I normally wouldn’t write news so early on from a group or developers that are unknown, but what they are offering looks quite promising, anyhow to read all about their work, check their GitHub page:
They also have a Discord server:
Both the GitHub and Discord look impressive.