From 7a5752a7489f6be1c7307455b33119888392a09d Mon Sep 17 00:00:00 2001
From: Maureen Helm <maureen.helm@nxp.com>
Date: Mon, 30 Dec 2019 17:46:17 -0600
Subject: [PATCH] zephyr: Enable littlefs.

Enables the littlefs (v1 and v2) filesystems in the zephyr port.

Example usage with the internal flash on the reel_board or the
rv32m1_vega_ri5cy board:

import os
from zephyr import FlashArea
bdev = FlashArea(FlashArea.STORAGE, 4096)
os.VfsLfs2.mkfs(bdev)
os.mount(bdev, '/flash')
with open('/flash/hello.txt','w') as f:
    f.write('Hello world')
print(open('/flash/hello.txt').read())

Things get a little trickier with the frdm_k64f due to the micropython
application spilling into the default flash storage partition defined
for this board. The zephyr build system doesn't enforce the flash
partitioning when mcuboot is not enabled (which it is not for
micropython). For now we can demonstrate that the littlefs filesystem
works on frdm_k64f by constructing the FlashArea block device on the
mcuboot scratch partition instead of the storage partition. Do this by
replacing the FlashArea.STORAGE constant above with the value 4.
---
 ports/zephyr/Makefile |  2 ++
 ports/zephyr/moduos.c | 10 ++++++++++
 2 files changed, 12 insertions(+)

diff --git a/ports/zephyr/Makefile b/ports/zephyr/Makefile
index 4357786110..0d62e5a7ac 100644
--- a/ports/zephyr/Makefile
+++ b/ports/zephyr/Makefile
@@ -18,6 +18,8 @@ MICROPY_HEAP_SIZE = 16384
 FROZEN_DIR = scripts
 
 MICROPY_VFS_FAT ?= 1
+MICROPY_VFS_LFS1 ?= 0
+MICROPY_VFS_LFS2 ?= 1
 
 # Default target
 all:
diff --git a/ports/zephyr/moduos.c b/ports/zephyr/moduos.c
index d33c317ce6..46745e656a 100644
--- a/ports/zephyr/moduos.c
+++ b/ports/zephyr/moduos.c
@@ -32,6 +32,10 @@
 #include "extmod/vfs_fat.h"
 #endif
 
+#if MICROPY_VFS_LFS1 || MICROPY_VFS_LFS2
+#include "extmod/vfs_lfs.h"
+#endif
+
 #if MICROPY_PY_UOS
 
 STATIC const mp_rom_map_elem_t uos_module_globals_table[] = {
@@ -54,6 +58,12 @@ STATIC const mp_rom_map_elem_t uos_module_globals_table[] = {
     #if MICROPY_VFS_FAT
     { MP_ROM_QSTR(MP_QSTR_VfsFat), MP_ROM_PTR(&mp_fat_vfs_type) },
     #endif
+    #if MICROPY_VFS_LFS1
+    { MP_ROM_QSTR(MP_QSTR_VfsLfs1), MP_ROM_PTR(&mp_type_vfs_lfs1) },
+    #endif
+    #if MICROPY_VFS_LFS2
+    { MP_ROM_QSTR(MP_QSTR_VfsLfs2), MP_ROM_PTR(&mp_type_vfs_lfs2) },
+    #endif
 };
 STATIC MP_DEFINE_CONST_DICT(uos_module_globals, uos_module_globals_table);