sys/riotboot: add tinyUSB DFU support

sys/riotboot/tinyusb_dfu.c

@@ -0,0 +1,38 @@
+/*
+ * Copyright (C) 2022 Gunar Schorcht
+ *
+ * This file is subject to the terms and conditions of the GNU Lesser
+ * General Public License v2.1. See the file LICENSE in the top level
+ * directory for more details.
+ */
+
+/**
+ * @ingroup sys_riotboot_usb_dfu
+ * @ingroup pkg_tinyusb_dfu
+ * @{
+ * @file    tinyUSB Device Firmware Upgrade initialization for riotboot
+ *
+ * @author  Gunar Schorcht <gunar@schorcht.net>
+ * @}
+ */
+
+#include "riotboot/magic.h"
+
+#include "tinyusb.h"
+#include "tinyusb_dfu.h"
+
+#define ENABLE_DEBUG    0
+#include "debug.h"
+
+extern void tinyusb_dfu_init(void);
+
+void riotboot_usb_dfu_init(unsigned forced)
+{
+    uint32_t *reset_addr = (uint32_t *)RIOTBOOT_MAGIC_ADDR;
+
+    if (forced == 1 || *reset_addr == RIOTBOOT_MAGIC_NUMBER) {
+        *reset_addr = 0;
+        tinyusb_setup();
+        tinyusb_dfu_init();
+    }
+}