I just did...
This phrase conveys that the speaker's action was limited in scope, without any deep implications; it is often used in spoken language.
Examples
その意見を言ったまでだ。
I just expressed that opinion.
彼を手伝ったまでだ。
I just helped him out.
勉強したまでだが、結果はどうなるかわからない。
I just studied, but I don't know what the result will be.
Quick check
彼を手伝っ___までだ。