tree 820385d24400bf155449ce22a2f49f2e365ae08d
parent ef9361fca08e09efb10656b9f23220db77d0e5d9
author Michael Hope <mlhx@google.com> 1518368859 +0100
committer Anas Nashif <anas.nashif@intel.com> 1546205050 -0500

lib: add crc7.

Used as a checksum on command messages when talking with MMC cards.

Implemented using the unwound bytewise implementation from
https://en.wikipedia.org/wiki/Computation_of_cyclic_redundancy_checks
which is a good mix of size and speed.

The API and naming matches lib/crc7.c in Linux.

Signed-off-by: Michael Hope <mlhx@google.com>