By placing this code into a distinct header, we can easily reuse it for benchmarking purposes.
The new SD card driver at 'os/src/drivers/sd_card/omap4' allows the use of an SD card with the Pandaboard as block service. Currently, the driver is using PIO, no DMA, and no IRQs. The driver can be tested using the 'os/run/sd_card.run' script.