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author | Sascha Hauer <s.hauer@pengutronix.de> | 2016-07-11 07:58:34 +0200 |
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committer | Sascha Hauer <s.hauer@pengutronix.de> | 2016-07-11 07:58:34 +0200 |
commit | e77acea709fb64b64ab884f5e946738d326df970 (patch) | |
tree | 5ffae8d7af61072d94c170c82e317a502d7cd681 /Documentation/user | |
parent | 4daa7a20c949e45ab9a93fd6ca7cb63bcebfb2ca (diff) | |
parent | e703d1ed730df92011f37692780b40fef110dd07 (diff) | |
download | barebox-e77acea709fb64b64ab884f5e946738d326df970.tar.gz barebox-e77acea709fb64b64ab884f5e946738d326df970.tar.xz |
Merge branch 'for-next/state'
Diffstat (limited to 'Documentation/user')
-rw-r--r-- | Documentation/user/state.rst | 46 | ||||
-rw-r--r-- | Documentation/user/user-manual.rst | 1 |
2 files changed, 47 insertions, 0 deletions
diff --git a/Documentation/user/state.rst b/Documentation/user/state.rst new file mode 100644 index 0000000000..c401f105bd --- /dev/null +++ b/Documentation/user/state.rst @@ -0,0 +1,46 @@ +Barebox State Framework +======================= + +The state framework is build to exchange data between Barebox and Linux +userspace using a non-volatile storage. There are several components involved. +Barebox has a state driver to access the variables. For the Linux Userspace +there is a userspace tool. + +Devicetree +---------- + +Currently the devicetree defines the layout of the variables and data. +Variables are fixed size. Several types are supported, see the binding +documentation for details. + +Data Formats +------------ + +The state data can be stored in different ways. Currently two formats are +available, ``raw`` and ``dtb``. Both format the state data differently. +Basically these are serializers. The raw serializer additionally supports a +HMAC algorithm to detect manipulations. + +Storage Backends +---------------- + +The serialized data can be stored to different backends which are automatically +selected depending on the defined backend in the devicetree. Currently two +implementations exist, ``circular`` and ``direct``. ``circular`` writes the +data sequentially on the backend storage device. Each save is appended until +the storage area is full. It then erases the block and starts from offset 0. +``circular`` is used for MTD devices with erase functionality. ``direct`` +writes the data directly to the file without erasing. + +For all backends multiple copies are written to handle read errors. + +Commands +-------- + +The ``state`` command can be used to store and manipulate the state. Using +``state`` without argument lists you all available states with their name. +``devinfo STATE_NAME`` shows you all variables and their values. ``state -s`` +stores the state. + +Starting Barebox will automatically load the last written state. If loading the +state fails the defaults are used. diff --git a/Documentation/user/user-manual.rst b/Documentation/user/user-manual.rst index be44f0d645..5841ea625c 100644 --- a/Documentation/user/user-manual.rst +++ b/Documentation/user/user-manual.rst @@ -31,6 +31,7 @@ Contents: system-setup reset-reason system-reset + state * :ref:`search` * :ref:`genindex` |