Trigger search in TW codemirror editor?

It’s been a loooong time since I worked with cm code. How would I trigger the search dialog in the codemirror editor from within a JavaScript macro/module? How do I get a handle on the specific instance?

From another tiddler I want to insert this macro:

<!-- code here opens the target tiddler for editing -->
<<codemirror-search "something">>

So, the target tiddler will already be open for editing, then I want to trigger the search dialog, stuff it with some text and start the search. Or…

If the search can be started without opening the search dialog, that’s fine too.