Implement additional PMBus quirks in the kernel

This is the `cesnet/2024-10-25--01` branch. The TL;DR version is that
the it *seems* that VOUT_MODE is not implemented on many more devices,
and when that's the case, one is expected to fall back to the linear11
encoding (which is not allowed for output voltages, but hey, who cares
about standards).

This is not just on some older modules, but also on the most recent DC
one from 2023.

Also, page updates were sometimes ignored (the device would return, say,
a 5V value on a 12V page, and the other way round). Let's increase the
timeout to 50ms and hope for the best^H^H^Hkeep an eye on how this thing
behaves now.

Change-Id: I56e8cbf660306332ef0fe5c23a75528d8eeec6f4
2 files changed
tree: a3301e5db70a398d3b742a2e95dac11f32a58969
  1. .gitmodules
  2. .zuul.yaml
  3. Config.in
  4. README.md
  5. board/
  6. ci/
  7. configs/
  8. crypto/
  9. dev-setup-git.sh
  10. doc/
  11. external.desc
  12. external.mk
  13. package/
  14. submodules/
  15. tests/
README.md

How to use this

This repository contains CzechLight-specific bits for Buildroot. Buildroot is a tool which produces system images for flashing to embedded devices. They have a nice documentation which explains everything that one might need.

The system architecture is described in another document. This is a quick build HOWTO.

Quick Start

Everything is in Gerrit. One should not need to clone anything from anywhere else. The build will download source tarballs of various open source components, though.

By default, each change of this repo uploaded to Gerrit causes the CI system to produce a firmware update. On Gerrit, the change will get a comment from Zuul with a link to the CI log server. Next to the logs, a file named artifacts/update.raucb can be used for updating devices.

Behind the scenes, the system uses Zuul with a configuration tracked in git.

Developer Workflow

Here's how to reproduce the build on a developer's workstation:

git clone ssh://$YOUR_LOGIN@cesnet.cz@gerrit.cesnet.cz:29418/CzechLight/br2-external czechlight
pushd czechlight
git submodule update --init --recursive
popd
mkdir build-clearfog
cd build-clearfog
../czechlight/dev-setup-git.sh
make czechlight_clearfog_defconfig
make -j8

A full rebuild takes about half an hour on a modern laptop.

WARNING: Buildroot is fragile. It is not safe to perform incremental builds after changing an "important" setting. Please check their manual for details.

Installing

Updates via RAUC

Apart from the traditional way of re-flashing the SD card or the eMMC from scratch, it's also possible to use RAUC to update. This method preserves the U-Boot version and the U-Boot's environment. Apart from that, everything starting with the kernel and the DTB file and including the root FS is updated. Configuration stored in /cfg is brought along and preserved as well.

To install an update:

# build node
make
rsync -avP images/update.raucb somewhere.example.org:path/to/web/root

# target, perhaps via an USB console or over SSH
rauc install http://somewhere.example.org/update.raucb
reboot

Once the updated FW slot boots, the configuration in /cfg will be automatically upgraded ("migrated") to the newest layout. A downgrade to an incompatible OS version might therefore fail during the next reboot. Completely removing all data in the newly updated slot's cfg partition will restore functionality, but it is effectively a factory reset.

Initial installation

Clearfog

On a regular Clearfog Base with an eMMC, one has to bootstrap the device first. If recovering a totally bricked board (or one that is fresh from factory), use the kwboot command to upload the initial, new enough U-Boot via the console. Power the system down, and ensure that the jumpers are set to 0 1 0 0 1 (default for eMMC boot is 0 0 1 1 1):

DIP switch positins for ClearFog eMMC/UART booting

Prepare a USB flash disk with a raw bootable image, images/usb-flash.img. Use a tool such as dd to overwrite the raw block device, do not copy the image file. Plug the USB flash disk in. Then, use U-Boot's kwboot tool:

./host/bin/kwboot -b ./u-boot-spl.kwb -t -p /dev/ttyUSB0

...and turn the power on. Once in U-Boot, execute:

usb start; fatload usb 0:1 00800000 boot.scr; source 00800000

The system will boot and flash the eMMC from the USB drive. Once the status LED starts blinking in yellow, data are being transferred to the eMMC. The light changes to solid yellow in later phases of the flashing process. Once everything is done, the status LED shows a solid white light and the system reboots automatically.

Turn off power, remove the USB flash, re-jumper the board (0 0 1 1 1), power-cycle, and configure MAC addresses at the U-Boot prompt. The MAC addresses are found on the label at the front panel.

=> setenv eth1addr 00:11:17:01:XX:XX
=> setenv eth2addr 00:11:17:01:XX:YY
=> setenv eth3addr 00:11:17:01:XX:ZZ

Also set up the system type:

Modelczechlight variable value
ROADM Line Degreesdn-roadm-line-g2
ROADM Flex Add/Dropsdn-roadm-add-drop-g2
ROADM Hi-Res Add/Dropsdn-roadm-hires-add-drop-g2
ROADM Coherent Add/Dropsdn-roadm-coherent-a-d-g2
Inline Amplifiersdn-inline-g2
BiDi Amplifier C-Band + 1572nmsdn-bidi-cplus1572-g2
BiDi Amplifier C-Band + 1572nm with OCMsdn-bidi-cplus1572-ocm-g2
=> setenv czechlight sdn-roadm-line-g2
=> saveenv
Saving Environment to MMC... Writing to redundant MMC(0)... OK
=> boot

Once the system boots (which currently requires a reboot for some unknown reason -- fsck, perhaps?), configure hostname, plug in the network cable, and update SW:

# hostnamectl set-hostname line-XYZSERIALNO
# cp /etc/hostname /cfg/etc/
# rauc install http://somewhere.example.org/update.raucb
# reboot

Beaglebone Black

Obtain a reasonable Linux distro image for BBB and flash it to a µSD card. Unlock eMMC boot partitions (echo 0 > /sys/class/block/mmcblk1boot0/force_ro; echo 0 > /sys/class/block/mmcblk1boot1/force_ro). Clean the eMMC data (blkdiscard /dev/mmcblk1). Flash the content of images/emmc.img to device's /dev/mmcblk1. Flash what fits into /dev/mmcblk1boot0 and /dev/mmcblk1boot1. Fetching the image over web (python3 -m http.server and wget http://...:8000/emmc.img -O - | dd of=/dev/mmcblk1 conv=sparse) works well.