Add SPIFFS Component to IDF

docs/api-reference/storage/index.rst

@@ -10,6 +10,7 @@ Storage API
    Virtual Filesystem <vfs>
    FAT Filesystem <fatfs>
    Wear Levelling <wear-levelling>
+   SPIFFS Filesystem <spiffs>
 
 
 Example code for this API section is provided in :example:`storage` directory of ESP-IDF examples.

docs/api-reference/storage/spiffs.rst

@@ -0,0 +1,53 @@
+SPIFFS Filesystem
+=================
+
+Overview
+--------
+
+SPIFFS is a file system intended for SPI NOR flash devices on embedded targets.
+It supports wear leveling, file system consistency checks and more.
+
+Notes
+-----
+
+ - Presently, spiffs does not support directories. It produces a flat structure. If SPIFFS is mounted under ``/spiffs`` creating a file with path ``/spiffs/tmp/myfile.txt`` will create a file called ``/tmp/myfile.txt`` in SPIFFS, instead of ``myfile.txt`` under directory ``/spiffs/tmp``. 
+ - It is not a realtime stack. One write operation might last much longer than another.
+ - Presently, it does not detect or handle bad blocks.
+
+Tools
+-----
+
+Host-Side tools for creating SPIFS partition images exist and one such tool is `mkspiffs <https://github.com/igrr/mkspiffs>`_.
+You can use it to create image from a given folder and then flash that image with ``esptool.py``
+
+To do that you need to obtain some parameters:
+
+- Block Size: 4096 (standard for SPI Flash)
+- Page Size: 256 (standard for SPI Flash)
+- Image Size: Size of the partition in bytes (can be obtained from partition table)
+- Partition Offset: Starting address of the partition (can be obtained from partition table)
+
+To pack a folder into 1 Megabyte image::
+
+    mkspiffs -c [src_folder] -b 4096 -p 256 -s 0x100000 spiffs.bin
+
+To flash the image to ESP32 at offset 0x110000::
+
+    python esptool.py --chip esp32 --port [port] --baud [baud] write_flash -z 0x110000 spiffs.bin
+
+See also
+--------
+
+- :doc:`Partition Table documentation <../../api-guides/partition-tables>`
+
+Application Example
+-------------------
+
+An example for using SPIFFS is provided in :example:`storage/spiffs` directory. This example initializes and mounts SPIFFS partition, and writes and reads data from it using POSIX and C library APIs. See README.md file in the example directory for more information.
+
+High level API Reference
+------------------------
+
+* :component_file:`spiffs/include/esp_spiffs.h`
+
+.. include:: /_build/inc/esp_spiffs.inc