117 lines
3.2 KiB
ReStructuredText
117 lines
3.2 KiB
ReStructuredText
.. _littlefs-sample:
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littlefs File System Sample Application
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#######################################
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Overview
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********
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This sample app demonstrates use of Zephyr's :ref:`file system API
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<file_system_api>` over `littlefs`_, using file system with files that:
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* count the number of times the system has booted
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* holds binary pattern with properly incremented values in it
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Other information about the file system is also displayed.
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.. _littlefs:
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https://github.com/ARMmbed/littlefs
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Requirements
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************
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Flash memory device
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-------------------
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The partition labeled "storage" will be used for the file system; see
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:ref:`flash_map_api`. If that area does not already have a
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compatible littlefs file system its contents will be replaced by an
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empty file system. You will see diagnostics like this::
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[00:00:00.010,192] <inf> littlefs: LittleFS version 2.0, disk version 2.0
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[00:00:00.010,559] <err> littlefs: Corrupted dir pair at 0 1
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[00:00:00.010,559] <wrn> littlefs: can't mount (LFS -84); formatting
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The error and warning are normal for a new file system.
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After the file system is mounted you'll also see::
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[00:00:00.182,434] <inf> littlefs: filesystem mounted!
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[00:00:00.867,034] <err> fs: failed get file or dir stat (-2)
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This error is also normal for Zephyr not finding a file (the boot count,
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in this case).
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Block device (e.g. SD card)
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---------------------------
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One needs to prepare the SD card with littlefs file system on
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the host machine with the `lfs`_ program.
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.. _lfs:
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https://www.thevtool.com/mounting-littlefs-on-linux-machine/
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.. code-block:: console
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sudo chmod a+rw /dev/sda
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lfs -d -s -f --read_size=512 --prog_size=512 --block_size=512 --cache_size=512 --lookahead_size=8192 --format /dev/sda
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lfs -d -s -f --read_size=512 --prog_size=512 --block_size=512 --cache_size=512 --lookahead_size=8192 /dev/sda ./mnt_littlefs
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cd ./mnt_littlefs
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echo -en '\x01' > foo.txt
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cd -
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fusermount -u ./mnt_littlefs
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Building and Running
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********************
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Flash memory device
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-------------------
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This example should work on any board that provides a "storage"
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partition. Two tested board targets are described below.
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You can set ``CONFIG_APP_WIPE_STORAGE`` to force the file system to be
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recreated.
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Block device (e.g. SD card)
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---------------------------
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This example has been devised and initially tested on :ref:`Nucleo H743ZI <nucleo_h743zi_board>`
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board. It can be also run on any other board with SD card connected to it.
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To build the test:
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.. zephyr-app-commands::
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:zephyr-app: samples/subsys/fs/littlefs
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:board: nucleo_h743zi
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:goals: build flash
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:gen-args: -DCONF_FILE=prj_blk.conf
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:compact:
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One can also set ``CONFIG_SDMMC_VOLUME_NAME`` to provide the mount point name
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for `littlefs` file system block device.
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NRF52840 Development Kit
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========================
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On this device the file system will be placed in the SOC flash.
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.. zephyr-app-commands::
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:zephyr-app: samples/subsys/fs/littlefs
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:board: nrf52840dk_nrf52840
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:goals: build
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:compact:
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Particle Xenon
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==============
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On this device the file system will be placed on the external SPI NOR
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flash memory.
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.. zephyr-app-commands::
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:zephyr-app: samples/subsys/fs/littlefs
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:board: particle_xenon
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:goals: build
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:compact:
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