Remove MBEDTLS_SHA256_PROCESS_ALT

Signed-off-by: Thomas Daubney <thomas.daubney@arm.com>
diff --git a/include/mbedtls/check_config.h b/include/mbedtls/check_config.h
index 2673229..090d0b4 100644
--- a/include/mbedtls/check_config.h
+++ b/include/mbedtls/check_config.h
@@ -750,9 +750,6 @@
 #if !defined(MBEDTLS_SHA256_C)
 #error "MBEDTLS_SHA256_USE_ARMV8_A_CRYPTO_* defined without MBEDTLS_SHA256_C"
 #endif
-#if defined(MBEDTLS_SHA256_PROCESS_ALT)
-#error "MBEDTLS_SHA256_PROCESS_ALT can't be used with MBEDTLS_SHA256_USE_ARMV8_A_CRYPTO_*"
-#endif
 
 #endif
 
diff --git a/include/mbedtls/mbedtls_config.h b/include/mbedtls/mbedtls_config.h
index e43c12d..add765d 100644
--- a/include/mbedtls/mbedtls_config.h
+++ b/include/mbedtls/mbedtls_config.h
@@ -350,44 +350,6 @@
  */
 //#define MBEDTLS_TIMING_ALT
 
-/**
- * \def MBEDTLS_SHA256_PROCESS_ALT
- *
- * MBEDTLS__FUNCTION_NAME__ALT: Uncomment a macro to let Mbed TLS use you
- * alternate core implementation of symmetric crypto or hash function. Keep in
- * mind that function prototypes should remain the same.
- *
- * This replaces only one function. The header file from Mbed TLS is still
- * used, in contrast to the MBEDTLS__MODULE_NAME__ALT flags.
- *
- * Example: In case you uncomment MBEDTLS_SHA256_PROCESS_ALT, Mbed TLS will
- * no longer provide the mbedtls_sha1_process() function, but it will still provide
- * the other function (using your mbedtls_sha1_process() function) and the definition
- * of mbedtls_sha1_context, so your implementation of mbedtls_sha1_process must be compatible
- * with this definition.
- *
- * \note If you use the AES_xxx_ALT macros, then it is recommended to also set
- *       MBEDTLS_AES_ROM_TABLES in order to help the linker garbage-collect the AES
- *       tables.
- *
- * Uncomment a macro to enable alternate implementation of the corresponding
- * function.
- *
- * \warning   MD5, DES and SHA-1 are considered weak and their use
- *            constitutes a security risk. If possible, we recommend avoiding
- *            dependencies on them, and considering stronger message digests
- *            and ciphers instead.
- *
- * \warning   If both MBEDTLS_ECDSA_SIGN_ALT and MBEDTLS_ECDSA_DETERMINISTIC are
- *            enabled, then the deterministic ECDH signature functions pass the
- *            the static HMAC-DRBG as RNG to mbedtls_ecdsa_sign(). Therefore
- *            alternative implementations should use the RNG only for generating
- *            the ephemeral key and nothing else. If this is not possible, then
- *            MBEDTLS_ECDSA_DETERMINISTIC should be disabled and an alternative
- *            implementation should be provided for mbedtls_ecdsa_sign_det_ext().
- *
- */
-//#define MBEDTLS_SHA256_PROCESS_ALT
 //#define MBEDTLS_SHA512_PROCESS_ALT
 //#define MBEDTLS_DES_SETKEY_ALT
 //#define MBEDTLS_DES_CRYPT_ECB_ALT
diff --git a/tf-psa-crypto/drivers/builtin/src/sha256.c b/tf-psa-crypto/drivers/builtin/src/sha256.c
index ec1e969..1bfb701 100644
--- a/tf-psa-crypto/drivers/builtin/src/sha256.c
+++ b/tf-psa-crypto/drivers/builtin/src/sha256.c
@@ -291,7 +291,6 @@
     return 0;
 }
 
-#if !defined(MBEDTLS_SHA256_PROCESS_ALT)
 static const uint32_t K[] =
 {
     0x428A2F98, 0x71374491, 0xB5C0FBCF, 0xE9B5DBA5,
@@ -312,8 +311,6 @@
     0x90BEFFFA, 0xA4506CEB, 0xBEF9A3F7, 0xC67178F2,
 };
 
-#endif
-
 #if defined(MBEDTLS_SHA256_USE_ARMV8_A_CRYPTO_IF_PRESENT) || \
     defined(MBEDTLS_SHA256_USE_ARMV8_A_CRYPTO_ONLY)
 
@@ -449,8 +446,7 @@
 #endif
 
 
-#if !defined(MBEDTLS_SHA256_PROCESS_ALT) && \
-    !defined(MBEDTLS_SHA256_USE_ARMV8_A_CRYPTO_ONLY)
+#if !defined(MBEDTLS_SHA256_USE_ARMV8_A_CRYPTO_ONLY)
 
 #define  SHR(x, n) (((x) & 0xFFFFFFFF) >> (n))
 #define ROTR(x, n) (SHR(x, n) | ((x) << (32 - (n))))
@@ -570,8 +566,7 @@
     return 0;
 }
 
-#endif /* !MBEDTLS_SHA256_PROCESS_ALT && !MBEDTLS_SHA256_USE_ARMV8_A_CRYPTO_ONLY */
-
+#endif /* !MBEDTLS_SHA256_USE_ARMV8_A_CRYPTO_ONLY */
 
 #if !defined(MBEDTLS_SHA256_USE_ARMV8_A_CRYPTO_ONLY)