Information about RTOS drivers

Simply put: are there any principles or guidelines in developing FreeRTOS (or just plain RTOS) drivers? I looked over the web but found no reference material. I’d like to know the “problem field”, I mean what things are to be kept in mind, what concerns there are, etc.
I’m developing a UART driver for LPC1768 as a case study. I’d like it to act as a router between several tasks and a generic peripheral, while avoiding priority inversion and supporting blocking and non-blocking I/O.
Is there somewhere I´d really profit from looking?