Enable OTP to store a permanent secret key.

It can be used by HSM or Fido to protect the keys and use it as MKEK.

src/fs/otp.h

@@ -0,0 +1,32 @@
+/*
+ * 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 _OTP_H_
+#define _OTP_H_
+
+#ifdef PICO_RP2350
+
+#define OTP_TEST_ROW 0xEF0
+
+#define OTP_KEY_1    OTP_TEST_ROW
+
+#endif
+
+extern const uint8_t *otp_key_1;
+
+#endif // _OTP_H_