bootloaders/riotboot_vfs: add VFS based bootloader

bootloaders/riotboot_common.mk

@@ -12,7 +12,9 @@ CFLAGS += -DRIOTBOOT
 # Disable unused modules
 CFLAGS += -DNDEBUG -DLOG_LEVEL=LOG_NONE
 DISABLE_MODULE += core_init core_msg core_panic
-DISABLE_MODULE += auto_init auto_init_%
+ifeq (,$(filter auto_init,$(USEMODULE)))
+  DISABLE_MODULE += auto_init auto_init_%
+endif
 DISABLE_MODULE += pm_layered
 
 # avoid using stdio

bootloaders/riotboot_vfs/Makefile

@@ -0,0 +1,12 @@
+# Default RIOT bootloader
+APPLICATION = riotboot_vfs
+
+USEMODULE += auto_init
+USEMODULE += riotboot_vfs
+USEMODULE += vfs_default
+
+# In riotboot we do everything on the ISR stack
+DISABLE_MODULE += core_thread
+CFLAGS += -DISR_STACKSIZE=2048
+
+include ../riotboot_common.mk

bootloaders/riotboot_vfs/main.c

@@ -0,0 +1,110 @@
+/*
+ * Copyright (C) 2021 ML!PA Consulting GmbH
+ *
+ * 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       Bootloader to load firmware from external storage via VFS
+ *
+ * @author      Benjamin Valentin <benjamin.valentin@ml-pa.com>
+ *
+ * @}
+ */
+
+#include <fcntl.h>
+#include "cpu.h"
+#include "panic.h"
+#include "riotboot/slot.h"
+#include "riotboot/vfs.h"
+#include "vfs.h"
+#include "vfs_util.h"
+#include "periph/flashpage.h"
+
+#define ENABLE_DEBUG 0
+#include "debug.h"
+
+#ifndef FLASHPAGE_SIZE
+#define FLASHPAGE_SIZE  1024
+#endif
+
+static void _flash_image(const char *file)
+{
+    static uint8_t buffer[FLASHPAGE_SIZE];
+    uint8_t *dst = (void *)(uintptr_t)SLOT0_OFFSET;
+    int res, fd = vfs_open(file, O_RDONLY, 0);
+
+    DEBUG("flashing %s…\n", file);
+
+    if (fd < 0) {
+        DEBUG("can't open: %d\n", fd);
+        return;
+    }
+
+    /* get image size */
+    off_t size = vfs_lseek(fd, 0, SEEK_END);
+    unsigned last_page = flashpage_page((void *)(uintptr_t)(SLOT0_OFFSET + size));
+
+    /* backup old image, close new image to conserve fds */
+    vfs_close(fd);
+    if (riotboot_vfs_dump_rom(RIOTBOOT_VFS_BACKUP_FILE) <= 0) {
+        DEBUG("can't backup current ROM");
+        return;
+    }
+
+    /* new firmware has to remove the update file */
+    vfs_file_from_buffer(RIOTBOOT_VFS_UPDATE_FILE,
+                         RIOTBOOT_VFS_BACKUP_FILE, sizeof(RIOTBOOT_VFS_BACKUP_FILE));
+
+    /* clear pages */
+    for (unsigned i = flashpage_page((void *)(uintptr_t)SLOT0_OFFSET); i <= last_page; ++i) {
+        DEBUG("erase page %u\n", i);
+        flashpage_erase(i);
+    }
+
+    DEBUG("write %lu bytes\n", size);
+    fd = vfs_open(file, O_RDONLY, 0);
+
+    /* flash image */
+    do {
+        res = vfs_read(fd, buffer, sizeof(buffer));
+        flashpage_write(dst, buffer, res);
+        dst += res;
+    } while (res > 0);
+
+    DEBUG_PUTS("done.");
+
+    vfs_close(fd);
+}
+
+void kernel_init(void)
+{
+    DEBUG_PUTS("riotboot VFS");
+
+    extern void auto_init(void);
+    auto_init();
+
+    /* get file to flash */
+    char update_file[64];
+    if (vfs_file_to_buffer(RIOTBOOT_VFS_UPDATE_FILE, update_file, sizeof(update_file)) > 0) {
+        _flash_image(update_file);
+    }
+    DEBUG("jump to 0x%x\n", SLOT0_OFFSET);
+    cpu_jump_to_image(SLOT0_OFFSET);
+
+    /* 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) {}
+}

sys/Makefile.dep

@@ -787,6 +787,19 @@ ifneq (,$(filter riotboot_serial, $(USEMODULE)))
   USEMODULE += checksum
 endif
 
+ifneq (,$(filter riotboot_vfs, $(USEMODULE)))
+  USEMODULE += riotboot
+  USEMODULE += vfs
+  USEMODULE += vfs_util
+  FEATURES_REQUIRED += periph_flashpage
+  # cpu_get_image_baseaddr() only implemented on Cortex-M
+  FEATURES_REQUIRED += cpu_core_cortexm
+
+  ifneq (1, $(RIOTBOOT_BUILD))
+    ROM_OFFSET = $(RIOTBOOT_LEN)
+  endif
+endif
+
 ifneq (,$(filter riotboot_reset, $(USEMODULE)))
   USEMODULE += riotboot
   USEMODULE += usb_board_reset

sys/Makefile.include

@@ -102,6 +102,10 @@ ifneq (,$(filter riotboot,$(FEATURES_USED)))
   include $(RIOTBASE)/sys/riotboot/Makefile.include
 endif
 
+ifneq (,$(filter riotboot_vfs,$(USEMODULE)))
+  include $(RIOTBASE)/sys/riotboot/Makefile.include
+endif
+
 ifneq (,$(filter skald, $(USEMODULE)))
   include $(RIOTBASE)/sys/net/ble/skald/Makefile.include
 endif