Flashdisk driver based on spidev

Jan.Sommer at dlr.de Jan.Sommer at dlr.de
Wed Mar 10 13:59:04 UTC 2021


We will probably at some point need support for Micron-based NOR-flash devices to store data which are connected via SPI.
I found the flashdisk API in RTEMS and was wondering if I understand everything correctly.
My idea would be to have the layers like this:
spidev-driver <-- micron-flashdisk-driver <-- (libblock?) <-- jffs2-filesystem <-- POSIX file operations

Another option would be to have the flashdisk-driver do the SPI transaction itself, but I am not sure if there is a lot performance to gain.
The bus setup will not change between consecutive read/write accesses to the memory (except for CS if multiple flash devices are present).
>From my work with the spidev drivers, which are currently in review, the overhead didn't seem very big to me for these conditions considering that writes will always be in the kB range due to the sector size.
Using the spidev API would have the benefit that the same flashdisk driver can be used with different SPI devices.

Are these assumptions reasonable or does someone have further suggestions to consider?

Best regards,


Deutsches Zentrum für Luft- und Raumfahrt e. V. (DLR)
German Aerospace Center
Institute for Software Technology | Software for Space Systems and Interactive Visualization | Lilienthalplatz 7 | 38108 Braunschweig | Germany

Jan Sommer

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