Minimal OpenSTLinux

[PGE]

We are building a custom embedded system based on STM32MP1 using customised OpenSTLinux. We are currently using the st-image-core as a starting point but we found it already heavy.

Is there any option or other images providing a smaller image ?

Also how can we merge the output images in a single fs. Currently there is bootfs, rootfs, userfs and vendorfs ?

Is there any documentation ressources about this topics ?

Thanks in advance

[Eldam]

Hello,

Maybe you could use:

https://wiki.st.com/stm32mpu/wiki/How_to_create_your_own_distribution

part 3.5 ?

[PGE]

Ok thank you !

What about the multiple fs ? This is specific to OpenSTLinux or generic to Yocto ?

[Eldam]

Hello,

Well i don't think its tied to Yocto.

I think Its tied to STµ way of doing OpenSTlinux distribution

By multiple fs:

you're thinking about one big (ext4/raw/iso) file to write to µSD card / emmc

or your thinking about worrying about multiple partitions "schématics"

By using multpiple partitions, its easier to modify the software concerned in "the good place" (sorry for my crappy english)

/boot --> boot related thing

/rootfs --> Main linux related thing

/userfs --> (maps to /usr/local) your "personnals" software

/vendorfs --> µST things

We use these way, and we are almost happy with it.

Nb: by using st-image-core you could have better support from STµ

Another link, sorry it's in french, but rather cool to ease yocto maze:

https://www.blaess.fr/christophe/yocto-lab/index.html

[PGE]

Thanks Eldam for the feedback,

About the big (ext4/raw/iso) file to write to µSD card I think I can use the FlashLayout_sdcard_stm32mp157c-*.raw file so this not worry me that much (expected the size of this file).

I am more worrying about multiple partitions "schematics" for maintenance and update of the devices in the field. I am used of having one read only fs with all the systems (boot, vendor and rootfs) and one RW fs with /var for log and data storage. So when we perform target update we update only the first partition.

I am used to buildroot with a single rootfs less than 100MB, here we are speaking multiple fs with a size almost in GB

You said you "are almost happy with it" why only "almost" ? May I ask you how do you perform update on the field ?

Thanks for the link I will read it (le français n'est pas un problème pour moi)

[Eldam]

Hello.

Update on the fields:

Our custom board have USB (host) connector, and button (µSD(initial debug) +emmc (boot on emmc).

So i've made another very simple rootfs (readonly). If we push the button at startup (uboot.scr monitoring this gpio event ) we boot to recover partition,

a script will monitor USB plug-in event, if detected , we launch another copy script for copying usbkey to filesystem (can copy ext4 partition or single files)

It work, i'm happy with it.

Its a home made update system, i know there is another (Linux,professional and so on) ways to do , but my linux experience is (unfortunately)limited.

almost happy with it: bad expression, don' mind.

Have a nice weekend!

[PatrickF]

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[PGE]

I found In st-machine-common-stm32mp.inc the following definition which seems to be perfectly what I needed. I tried to define them all 3 to "0" in my own config. This resulted in the generation of a single root image. Unfortunately this single image do not contain files from BOOTFS, VENDORFS and USERFS.

Any idea how I can redirect these files in root partition ?

# Enable use of extra partition(s)
ST_BOOTFS   ?= "1"
ST_VENDORFS ?= "1"
ST_USERFS   ?= "1"

More generally speaking is there any documentation about all the ST layer on top of Yocto ? There is a lot of ST_* variable and other customization which are completely different than "normal" yocto.

Thanks in advance

[Eldam]

Hello,

No real idea, we don't use "create your own machine part" (doc too confusing for me)

No more hint for this subject,

désolé!