bootutil: Add prototypes for crypto backend initialization API

Adds prototypes for:
 bootutil_crypto_backend_init
 bootutil_crypto_backend_deinit
that will be expected to be provided by crypto backend in case
when MCUBOOT_CRYPTO_BACKEND_HAS_INIT is enabled.

Signed-off-by: Dominik Ermel <[email protected]>

Author: de-nordic

boot/bootutil/include/bootutil/crypto/backend.h

@@ -0,0 +1,33 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * Copyright (c) 2025 Nordic Semiconductor ASA
+ */
+
+#ifndef __BOOTUTIL_CRYPTO_BACKEND_H__
+#define __BOOTUTIL_CRYPTO_BACKEND_H__
+
+#if defined(MCUBOOT_CRYPTO_BACKEND_HAS_INIT)
+/* Backend specific implementation for crypto subsystem
+ * initialization.
+ * MCUboot is supposed to call this function before
+ * any crypto operation, including sha functions,
+ * is executed.
+ * Returns true on success. The function can also just fault
+ * and topple entire boot process.
+ */
+bool bootutil_crypto_backend_init(void);
+
+/* Backend specific implementation for crypto subsystem
+ * deinitialization.
+ * No more cryptographic operations are expected to be
+ * invoked by MCUboot after this founction is called.
+ * Returns true on success.
+ */
+bool bootutil_crypto_backend_deinit(void);
+#else
+#define bootutil_crypto_backend_init() (true)
+#define bootutil_crypto_backend_deinit() (true)
+#endif
+
+#endif /* __BOOTUTIL_CRYPTO_BACKEND_H__ */