What is the Difference between initial Peripheral initialisation[For Boot process] and peripheral initialised with device drivers.

Dear All,


             I have been working with x-loaders and u-boot loaders for some time...when a bare metal processor boots has firmware which has minimal drivers for making the peripherals [UART,USB,EMAC,NAND] initialisation and can fetch some data to RAM Location...in this case the Peripheral is UP and hence why i Need to write or Load drivers integrated in the OS.


Please Post some Links where i can read the difference between minimal driver requirement and complete driver initialisation...Please help me out in understanding this concept.


Hrishikesh A Choudhary.