Hippie history? Seeking info on 1970's SF restaurant where no talking was allowed!

In the mid 1970's there was a very simple SF restaurant, maybe in the South of Market area or the Mission. There was no menu, and the food was served cafeteria style. The food was always the same... a vegetarian curry, rice, dal, chutney and chai. Delicious, and cheap... maybe $1.50 or $2 for the meal. I think the interior walls were pale green, and talking was completely prohibited. Does anyone remember that place? I would love to know the name and what the story was behind it!