x86: Add console command to display CBMEM console buffer

This command is useful to allow to observe messages generated by
coreboot and u-boot until present. In particular it is handy when
u-boot is instrumented to fall through into console mode on startup
errors.

BRANCH=none
BUG=chrome-os-partner:13819
TEST=manual

  . USE=pcserial emerge-link chromeos-coreboot-link chromeos-u-boot \
     chromeos-bootimage
  . boot a Link device using generated nv_image-link.bin
  . at the 'boot >' prompt enter cbc_dump, observe the console
    contents dumped on the screen

Change-Id: Ib59f5edfd549880c593f85830fef07313df36e44
Signed-off-by: Vadim Bendebury <vbendeb@chromium.org>
Reviewed-on: https://gerrit.chromium.org/gerrit/33545
Reviewed-by: Simon Glass <sjg@chromium.org>
1 file changed