Add crypto_deinit function for crypto_backend module

Bootloader needs to have a mechanism to de-initialize crypto, in case some HW accelerator
is being used. This adds the needed function for it

Signed-off-by: Jukka Laitinen <jukkax@ssrc.tii.ae>

platforms/common/include/px4_platform_common/crypto_backend.h

@@ -93,6 +93,13 @@ bool keystore_put_key(keystore_session_handle_t handle, uint8_t idx, uint8_t *ke
 
 void crypto_init(void);
 
+/*
+ * De-initialize hw level crypto
+ * This may be called to shut down hw level crypto
+ */
+
+void crypto_deinit(void);
+
 /*
  * Open a session for performing crypto functions
  * algorithm: The crypto algorithm to be used in this session

platforms/nuttx/src/bootloader/common/bl.c

@@ -392,6 +392,10 @@ jump_to_app()
 
 #endif
 
+#ifdef BOOTLOADER_USE_SECURITY
+	crypto_deinit();
+#endif
+
 	/* just for paranoia's sake */
 	arch_flash_lock();
 

src/drivers/sw_crypto/crypto.c

@@ -151,6 +151,10 @@ void crypto_init()
 	clear_key_cache();
 }
 
+void crypto_deinit()
+{
+}
+
 crypto_session_handle_t crypto_open(px4_crypto_algorithm_t algorithm)
 {
 	crypto_session_handle_t ret;