difference between this config and OpenWRT18.06

[DanielRIOT]

Hi, what are the differences between this repo and the one from Openwrt ( LEDE ) 18.06 in terms of the Yun's configuration, especially the serial console interface ?

I've built an image form 18.06 and it boots but seems to reconfigure the baudrate at some stage during the kernel boot ( it starts at 250000 baud and one can see kernel messages then after about 2 seconds it goes to 9600 baud )

stty reports that 250000 is an invaid baudrate, but this can be set by manually running

reset-serial /dev/ttyATH0

after boot ( from SSH ) or in rc.local.

How is the console configured in this version vs what is done in the mainstream Openwrt one so that the serial console works from this image , but not from the other one ?

-Ive also included the yun-config and yun-scripts in that build and built them into the kernel [*] and not as modules.

a forum post on is here, but no luck with Yun specific information from their side : https://forum.openwrt.org/t/arduino-yun-uart-console-baudrate-issue/19002/5
-Daniel

[facchinm]

Hi @DanielRIOT ,
choosing 250000bps as baud rate was an unfortunate decision at the time but we have to live with that; there's a ugly patch that needs to be backported every time that enables that baudrate (https://github.com/arduino/lede-yun/blob/master/target/linux/ar71xx/patches-4.9/821-serial-core-add-support-for-boot-console-with-arbitr.patch) .
The reconfiguration to 9600 happens because bootargs request 250000 but fails (without that patch) and falls back to the minimum supported speed (9600).
I'd love to be able at some point to adopt mainline openwrt, so any advice or code could really help in this!

[DanielRIOT]

Hi @facchinm

that makes sense,
a workaround I had is :
serial-reset /dev/ttyATH0 in rc.local so it comes up later.

Thank you for pointing me to the patch, I updated it and did a test compile on 18.06 ( this repo ) and it seems to build happily- will test it when i get to a Yun tomorrow...

I also added these feeds to my feeds.conf so I can pull in yun-scripts[] and yun-config[] and yun-bridge[m].
src-git arduino https://github.com/arduino/openwrt-arduino-packages.git;for-lede-next
after that one can follow the "regular" openwrt build process and all seems well ( I have gotten some "invalid image type" messages when doing sysupgrade, and will hunt those down soon too.

I'm using the uBoot from your Go-updater for all of these and it works without issue.

I also found we can set the kernel serial port to 115200, and then only u-boot needs to be set to match
find Yun in /target/linux/ar71xx/image/generic.mk and set CONSOLE := ttyATH0,115200

115200 will probably break the yun-bridge as it expects the higher baudrate between the AVR and the AR9331

The updated patch for the new kernel is here...
821-serial-core-add-support-for-boot-console-with-arbitr.zip

[DanielRIOT]

I tested the ported patch on my Yun and it seems to work as expected ( baudrate at 250000 )

I've also tested loading sketches to the AVR via the network upload and it runs fine,
I haven't added the JuCI "desktop" interface yet as I prefer the Openwrt configuration panel for my current project.

[satmandu]

Could someone upload an 18.06.x image for the Yun? Or will there be an official one?

[DanielRIOT]

hi @satmandu , you can get a pre-built image from openWRT/LEDE here :
https://downloads.openwrt.org/releases/18.06.1/targets/ar71xx/generic/openwrt-18.06.1-ar71xx-generic-arduino-yun-squashfs-sysupgrade.bin

it doesn't have the baudrate patch applied, so it might be better to build your image from source using the openWRT build tools so you can apply the patch - at least until the patch is integrated into their current release

[satmandu]

@DanielRIOT Any chance you'd be willing to put up a diff to the 18.06.x tree on github showing the changes you had to get a minimal working build for the yun?

The 18.06.1 release sysupgrade file is missing enough yun specific stuff (such as required kernel patches to get avrdude to work) to not connect easily to the arduino side.

[DanielRIOT]

@satmandu will try and put up a repo later this week - You'll have to build it yourself to get the yun specific stuff in there ( fixed baudrate, AVRdude, Yun conf and Yun scripts)

• I have not tried getting JUCi ( The "desktop" new Yuns present) or the Arduino web frontend ( classic arduino one ) up as I use the standard Openwrt frontend and I dont use the REST interface to control the AVR, but network programming works OK

[satmandu]

Thanks. The Yun specific stuff in the tree aside from JUCi and the Arduino frontend area really all that I am looking for.

[DanielRIOT]

@satmandu ,

• I cloned the master repo from openwrt ( https://github.com/openwrt/openwrt/tree/master ) and set up my build as this instructs )

• Then added the arduino packages to feeds.conf.default ( https://github.com/arduino/openwrt-arduino-packages ) ( you can use this as an example )

• called ./scripts/feeds update -a and ./scripts/feeds install -a to get them into my "packages" directory and so they show up in menuconfig.

• also needed to add the serial baudrate patch to the new kernel ( 4.14 ) in /target/linux/ar71xx/patches-4.14
  951-MIPS-serial-core-add-support-for-arb-baudrates.zip if you don't do this the Yun will have a console at 9600 baudrate and bridge will also not work as expected at al times. - you can update the yunserial Arduino sketch to have 9600 as an option :D )

• run make menuconfig

• In menuconfig select the target system Atheros ar7xxx/ar9xxx , Subtarget : Generic , target profile as Arduino Yun

• select yun-scripts and yun-conf and luci-app-arduino-webpanel and any other things you think might be useful

You might have to update u-boot ( using the go-updater - it works really well ), and then load your new image with ssh ( scp runs if you have ssh open, so you can use winSCP in windows or the regular linux scp to copy it to /tmp)

• to flash : run sysupgrade -v -F /tmp/openwrt-ar71xx-generic-arduino-yun.bin from terminal ( for some reason the magic number and "board name" doesn't get included or is calculated wrong and then the regular sysupgrade and web upgrade do not accept the new image and thus you need the Force -F flag

you might need to see compare which packages to include in your build to get the same behavior as Arduino's Yun build (
I haven't focused on recreating the Yun build completely - Yun is a convenient ar71xx platform for me to experiment on with OpenWrt specific stuff

all of this might brick your Yun during any stage (happened to me lots of times and its recoverable as long as you don't wipe out u-boot or ART partition on the flash, but you can always use something like Flashrom , or a arduino due/zero / any 3v3 device to read out or reprogram the flash on the Yun to put u-boot and ART back assuming you backed it up beforehand - you can do that from terminal - check out this wiki )

The "Sysupgrade" image that is built by the regular build can be uploaded to the flash from u-boot via tftp directly to the boot memory location ( 0x9f050000 ) - check the u-boot bootargs to get the correct location - it also has a lot of other things set up in there that give a useful insight into the system as it differs from the "regular" ar71xx targets

also keep mindful that there are some bugs in the newer kernel that may pop up as lots of things have changed ( i get occasional restarts when I change wifi channel on the ar71xx platforms )

I built this image :
Uploading openwrt-ar71xx-generic-arduino-yun-squashfs-sysupgrade.zip…

[satmandu]

Thanks. That parallels much of what I was doing. It is reassuring to hear that you did much of the same, and yes I noted that annoyance with having to run sysupgrade -v -F too.

Now that 18.06.2 is rolling out I'm tempted to just use https://github.com/openwrt/openwrt/tree/openwrt-18.06 as a base repo to work off of.

[satmandu]

@DanielRIOT You mean ./scripts/feeds install -a not ./scripts/feeds/install -a .

[satmandu]

@DanielRIOT Did you ever run into this error?

 * check_data_file_clashes: Package yunbridge wants to install file openwrt/build_dir/target-mips_24kc_musl/root-ar71xx/usr/bin/pretty-wifi-info.lua
        But that file is already provided by package  * yun-scripts
 * opkg_install_cmd: Cannot install package yunbridge.