This is based around the SMBIOS event log specification but
expanded with OEM event types to support more specific and
relevant system events.
It requires flash storage and a minimum 4K block (or flash block
size) that should be allocated in the FMAP.
A copy of the event log is maintained in memory for convenience
and speed and the in-memory copy is written to flash at specific
points.
The log is automatically shunk when it reaches a configurable
full threshold in order to not get stuck with a full log that
needs OS help to clear.
ELOG implements the specification published here:
http://code.google.com/p/firmware-event-log/wiki/FirmwareEventLogDesign
And is similar to what we use in other firmware at Google.
This implementation does not support double-buffered flash
regions. This is done because speed is valued over the log
reliability and it keeps the code simpler for the first version.
This is a large commit and by itself it just provides a new
driver that is made available to coreboot. Without additional
patches it is not very useful, but the end result is an event
log that will contain entries like this:
171 | 2012-06-23 16:02:55 | System boot | 285
172 | 2012-06-23 16:02:55 | EC Event | Power Button
173 | 2012-06-23 16:02:55 | SUS Power Fail
174 | 2012-06-23 16:02:55 | System Reset
175 | 2012-06-23 16:02:55 | ACPI Wake | S5
Change-Id: I985524c67f525c8a268eccbd856c1a4c2a426889
Signed-off-by: Duncan Laurie <dlaurie@chromium.org>
Reviewed-on: http://review.coreboot.org/1311
Tested-by: build bot (Jenkins)
Reviewed-by: Ronald G. Minnich <rminnich@gmail.com>
