The LoongArch ISA is used on CPUs created by Loongson, who have internally created a ?loongarch64 port that they are aiming to turn into an architecture available from Debian.
References
Discussions: <b5a53692-592c-2e3d-a996-a8d6692f4eb1@loongson.cn> <12133b5.b049.182493b9628.Coremail.sangmeng@loongson.cn>
Mailing list request: 989125
Documentation: https://loongson.github.io/LoongArch-Documentation/
Unofficial FAQ: https://blog.xen0n.name/en/posts/tinkering/loongarch-faq/