Add sha256_alt to use sha256 hardware in RP2350.

Other boards and SHA224 use mbedtls implementation.

Signed-off-by: Pol Henarejos <pol.henarejos@cttc.es>

config/rp2350/alt/sha256_alt.h

@@ -0,0 +1,36 @@
+/*
+ * This file is part of the Pico Keys SDK distribution (https://github.com/polhenarejos/pico-keys-sdk).
+ * Copyright (c) 2022 Pol Henarejos.
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation, version 3.
+ *
+ * This program is distributed in the hope that it will be useful, but
+ * WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
+ * General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program. If not, see <http://www.gnu.org/licenses/>.
+ */
+
+#ifndef _SHA256_ALT_H_
+#define _SHA256_ALT_H_
+
+#include "pico_keys.h"
+#include "pico/sha256.h"
+
+typedef struct mbedtls_sha256_context {
+    pico_sha256_state_t MBEDTLS_PRIVATE(pico_state);
+#if defined(MBEDTLS_SHA224_C)
+    unsigned char MBEDTLS_PRIVATE(buffer)[64];   /*!< The data block being processed. */
+    uint32_t MBEDTLS_PRIVATE(total)[2];          /*!< The number of Bytes processed.  */
+    uint32_t MBEDTLS_PRIVATE(state)[8];          /*!< The intermediate digest state.  */
+    int MBEDTLS_PRIVATE(is224);                  /*!< Determines which function to use:
+                                                    0: Use SHA-256, or 1: Use SHA-224. */
+#endif
+}
+mbedtls_sha256_context;
+
+#endif /* _SHA256_ALT_H_ */