bootloaders/riotboot: add serial bootloader

bootloaders/riotboot_serial/Makefile

@@ -0,0 +1,14 @@
+# Default RIOT bootloader
+APPLICATION = riotboot_serial
+
+# Include serial bootloader functionality
+USEMODULE += riotboot_serial
+
+# RIOT codebase
+RIOTBASE ?= $(CURDIR)/../../
+
+include $(RIOTBASE)/Makefile.include
+
+# limit riotboot bootloader size
+RIOTBOOT_SERIAL_LEN ?= $(RIOTBOOT_LEN)
+ROM_LEN := $(RIOTBOOT_SERIAL_LEN)

bootloaders/riotboot_serial/Makefile.ci

@@ -0,0 +1,3 @@
+BOARD_INSUFFICIENT_MEMORY := \
+    phynode-kw41z \
+    #

bootloaders/riotboot_serial/main.c

@@ -0,0 +1,93 @@
+/*
+ * Copyright (C) 2017 Kaspar Schleiser <kaspar@schleiser.de>
+ *                    Inria
+ *
+ * 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     bootloaders
+ * @{
+ *
+ * @file
+ * @brief      Serial UART riot-based bootloader
+ *
+ * @author     Kaspar Schleiser <kaspar@schleiser.de>
+ * @author     Francisco Acosta <francisco.acosta@inria.fr>
+ * @author     Benjamin Valentin <benjamin.valentin@ml-pa.com>
+ *
+ * @}
+ */
+
+#include "cpu.h"
+#include "panic.h"
+#include "riotboot/slot.h"
+#include "riotboot/serial.h"
+
+static int _get_slot(void)
+{
+    uint32_t version = 0;
+    int slot = -1;
+
+    if (!IS_USED(MODULE_RIOTBOOT_SLOT)) {
+        return -1;
+    }
+
+    for (unsigned i = 0; i < riotboot_slot_numof; i++) {
+        const riotboot_hdr_t *riot_hdr = riotboot_slot_get_hdr(i);
+        if (riotboot_slot_validate(i)) {
+            /* skip slot if metadata broken */
+            continue;
+        }
+        if (riot_hdr->start_addr != riotboot_slot_get_image_startaddr(i)) {
+            continue;
+        }
+        if (slot == -1 || riot_hdr->version > version) {
+            version = riot_hdr->version;
+            slot = i;
+        }
+    }
+
+    return slot;
+}
+
+static void _boot_default(int slot)
+{
+    if (!IS_USED(MODULE_RIOTBOOT_SLOT)) {
+        /* boot 'raw' firmware image */
+        cpu_jump_to_image(SLOT0_OFFSET);
+        return;
+    }
+
+    if (slot == -1) {
+        slot = _get_slot();
+    }
+
+    if (slot != -1) {
+        riotboot_slot_jump(slot);
+    }
+}
+
+void kernel_init(void)
+{
+    int slot = -1;
+
+    if (IS_USED(MODULE_RIOTBOOT_SERIAL)) {
+        slot = riotboot_serial_loader();
+    }
+
+    irq_disable();
+    _boot_default(slot);
+
+    /* serious trouble! nothing to boot */
+    while (1) {}
+}
+
+NORETURN void core_panic(core_panic_t crash_code, const char *message)
+{
+    (void)crash_code;
+    (void)message;
+    while (1) {}
+}