libpayload: Implement reading from CBMEM console

To support showing CBMEM logs on recovery screen, add a function
cbmem_console_snapshot() to copy the CBMEM console to an allocated
buffer. Non-printable characters are automatically replaced with '?' to
ensure the returned string is printable.

BRANCH=none
BUG=b:146105976
TEST=emerge-nami libpayload

Change-Id: Ie324055f5fd8276f1d833fc9d04f60a792dbb9f6
Signed-off-by: Yu-Ping Wu <yupingso@chromium.org>
Reviewed-on: https://review.coreboot.org/c/coreboot/+/37667
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
Reviewed-by: Hung-Te Lin <hungte@chromium.org>

0 files changed, 0 insertions, 0 deletions