The current caching layer only has a single buffer for
writing and reading. The FAT driver often accesses the
fat and then data again, which currently can't be cached.
Reimplement this with a list of cached chunks. The number
of chunks and their sizes are currently hardcoded, but
that could be easily made configurable.
Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de>
This adds a simple block layer to barebox. Reading and writing
to block devices can be painfully slow without caching, so
add a simple caching layer here.
Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de>