lib: Add crc4 module

Add a little helper for crc4 calculations. This works 4-bits-at-a-time,
using a simple table approach.

We will need this in the FSI core code, as well as any master
implementations that need to calculate CRCs in software.

Signed-off-by: Jeremy Kerr <jk@ozlabs.org>
Signed-off-by: Chris Bostic <cbostic@linux.vnet.ibm.com>
Signed-off-by: Joel Stanley <joel@jms.id.au>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

1 files changed, 8 insertions, 0 deletions

diff --git a/lib/Kconfig b/lib/Kconfig
index 0c8b78a9ae2e..d2fd2623721e 100644
--- a/lib/Kconfig
+++ b/lib/Kconfig
@@ -158,6 +158,14 @@ config CRC32_BIT
 
 endchoice
 
+config CRC4
+        tristate "CRC4 functions"
+        help
+          This option is provided for the case where no in-kernel-tree
+          modules require CRC4 functions, but a module built outside
+          the kernel tree does. Such modules that use library CRC4
+          functions require M here.
+
 config CRC7
         tristate "CRC7 functions"
         help