+int mucse_read_mbx(struct mucse_hw *hw, u32 *msg, u16 size)
+{
+	struct mucse_mbx_info *mbx = &hw->mbx;
+
+	/* limit read size */
+	min(size, mbx->size);
+	return mbx->ops->read(hw, msg, size);

As well as the obvious bug pointed out by others, isn't this condition
actually indicating a bug somewhere else? If size is bigger than
mbx->size, the caller is broken. You probably want a dev_err() here,
and return -EINVAL, so you get a hint something else is broken
somewhere.

	Andrew