commit e629bf37458a344e01a1e0d1f2da189fa3698104
author David Brown <david.brown@linaro.org> Mon Apr 24 13:37:33 2017 -0600
committer David Brown <david.brown@linaro.org> Thu Apr 27 16:31:12 2017 -0600
tree 89698d022a398bbbb0ff55ec01a2e6f5d4f9df51
parent d7e350df7d13b41e35aa0eda04152caf3b2cb157

Generalize SHA256 code to allow tinycrypt support

When building with ECDSA P-256 as the signature algorithm, we are still
bringing in SHA256 and some ASN.1 code from mbed TLS.  Fix part of this
by wrapping the hash functions with general routines (inline functions)
allowing to select between mbed TLS and Tinycrypt for the
implementation.

Update the Zephyr config files so that the Tinycrypt version is used
when building the ECDSA P-256 signing variant.

boot/zephyr/include/config-asn1.h

diff --git a/boot/zephyr/include/config-asn1.h b/boot/zephyr/include/config-asn1.h
index e772ceb..25d33fb 100644
--- a/boot/zephyr/include/config-asn1.h
+++ b/boot/zephyr/include/config-asn1.h
@@ -40,7 +40,7 @@
 // #define MBEDTLS_BIGNUM_C
 // #define MBEDTLS_MD_C
 // #define MBEDTLS_OID_C
-#define MBEDTLS_SHA256_C
+// #define MBEDTLS_SHA256_C
 
 #include "mbedtls/check_config.h"