Hi all,

I'd like to propose to add sub-folders under docs/design_documents to collect the documents on the same topic. Currently, there are already 21 documents in total under docs/design_documents and the number may grow rapidly. It can be more clear if we can organize the documents on the same topic into a dedicated sub-folder under docs/design_documents.

Please help review the patch set https://review.trustedfirmware.org/q/topic:%22design-doc-subdir%22+(status:o...) if the proposal sound interesting. I move dual-cpu and TF-M Profiles related documents to their dedicated folder respectively in the patches. Any comment is welcome!

In current patches, the html pages are still put in the same level during Sphinx build. It is because design documents are grouped by document status, instead of document hierarchy. The html pages can be further organized as well if we switch to group html according to folder structures.

Best regards, Hu Ziji