This is a platform driver for Versatile Express' "system
register" block. It's a random collection of registers providing
the following functionality:
- low level platform functions like board ID access; in order to
use those, the driver must be initialized early, either statically
or based on the DT
- config bus bridge via "system control" interface; as the response
from the controller does not generate interrupt (yet), the status
register is periodically polled using a timer
- pseudo GPIO lines providing MMC card status and Flash WP#
signal control
- LED interface for a set of 8 LEDs on the motherboard, with
"heartbeat", "mmc0" and "cpu0" to "cpu5" as default triggers
Signed-off-by: Pawel Moll <pawel.moll@arm.com>