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.

TIA!