Implement XAP 'secure' core requirements (#16843)

Co-authored-by: Drashna Jaelre <drashna@live.com>
Co-authored-by: Stefan Kerkmann <karlk90@pm.me>

quantum/secure.h

@@ -0,0 +1,67 @@
+// Copyright 2022 QMK
+// SPDX-License-Identifier: GPL-2.0-or-later
+
+#pragma once
+
+/** \file
+ *
+ * Exposes a set of functionality to act as a virtual padlock for your device
+ * ... As long as that padlock is made of paper and its currently raining.
+ */
+
+#include <stdint.h>
+#include <stdbool.h>
+
+/** \brief Available secure states
+ */
+typedef enum {
+    SECURE_LOCKED,
+    SECURE_PENDING,
+    SECURE_UNLOCKED,
+} secure_status_t;
+
+/** \brief Query current secure state
+ */
+secure_status_t secure_get_status(void);
+
+/** \brief Helper to check if unlocking is currently locked
+ */
+#define secure_is_locked() (secure_get_status() == SECURE_LOCKED)
+
+/** \brief Helper to check if unlocking is currently in progress
+ */
+#define secure_is_unlocking() (secure_get_status() == SECURE_PENDING)
+
+/** \brief Helper to check if unlocking is currently unlocked
+ */
+#define secure_is_unlocked() (secure_get_status() == SECURE_UNLOCKED)
+
+/** \brief Lock down the device
+ */
+void secure_lock(void);
+
+/** \brief Force unlock the device
+ *
+ * \warning bypasses user unlock sequence
+ */
+void secure_unlock(void);
+
+/** \brief Begin listening for an unlock sequence
+ */
+void secure_request_unlock(void);
+
+/** \brief Flag to the secure subsystem that user activity has happened
+ *
+ * Call when some user activity has happened and the device should remain unlocked
+ */
+void secure_activity_event(void);
+
+/** \brief Flag to the secure subsystem that user has triggered a keypress
+ *
+ * Call to trigger processing of the unlock sequence
+ */
+void secure_keypress_event(uint8_t row, uint8_t col);
+
+/** \brief Handle various secure subsystem background tasks
+ */
+void secure_task(void);