Marcus Folkesson

Embedded Linux Artist

Git version in cmake

Git version in CMake All applications have versions. The version should somehow be exposed in the application to make it possible to determine which application we are actually running. I've seen a plenty of variants on how this is achieved, some are good and some are really bad. Since it's such a common thing, I thought I'd show how I usually do it. I use to let CMake determine the version based on git describe and tags, the benefit's that it is part of the build process (i.

Posted by Marcus Folkesson on Tuesday, November 14, 2023

TIL - sort in vim

TIL - Sort in VIM TIL, Today I Learned, is more of a "I just figured this out: here are my notes, you may find them useful too" rather than a full blog post After 15+ years of daily VIM usage I just discovered the :sort function. Quite embarassing. It is also possible to sort in revese ( :sort!) and remove duplicate lines ( :sort u).

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Posted by Marcus Folkesson on Thursday, November 2, 2023

Burn eFuses for MAC address on iMX8MP

Burn eFuses for MAC address on iMX8MP The iMX (iMX6, iMX7, iMX8) has a similiar OCOTP (On-Chip One Time Programmable) module that store, for example the MAC addresses for the internal ethernet controllers. The reference manual is not clear either on the byte order or which bytes belong to which MAC address when there are several. In fact, I had to look at the U-boot implementation [1] to know for sure how these fuses is used:

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Posted by Marcus Folkesson on Saturday, October 28, 2023

Loopback with two (physical) ethernet interfaces

Loopback with two (physical) ethernet interfaces Imagine that you have an embedded device with two physical ethernet ports. You want to verify the functionality of both these ports in the manufacturing process, so you connect an ethernet cable between the ports, setup IP addresses and now what? As Linux (actually the default network namespace) is aware of the both adapters and their IP/MAC-addresses, the system see no reason to send any traffic out.

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Posted by Marcus Folkesson on Saturday, October 21, 2023

TIL - notmuch-lore

TIL - notmuch-lore TIL, Today I Learned, is more of a "I just figured this out: here are my notes, you may find them useful too" rather than a full blog post Notmuch [1] is an mail indexer and is a great tool to search in high-volume mailboxes (e.g. mailing lists). Being subscribed to all these mailing lists and retreiving all mails over IMAP daily could be quite annoying and harm your mail quota.

Posted by Marcus Folkesson on Saturday, October 21, 2023

kas-container and QEMU

kas-container and QEMU KAS KAS [1] is a setup tool for bitbake based projects such as Yocto. There are many similiar alternatives out there and I've tried most of them, but my absolute favorite is KAS. In order to use KAS, you have to setup a YAML file to contain information about your machine, distribution, meta layers and local configuration. Here is a small example configuration copied from the KAS documentation:

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Posted by Marcus Folkesson on Wednesday, October 18, 2023

TIL - git man-pages

TIL - git man-pages TIL, Today I Learned, is more of a "I just figured this out: here are my notes, you may find them useful too" rather than a full blog post I'm a big user of man-pages. Today I found a set of pages that I've not noticed before when I was reading man git: SEE ALSO gittutorial(7), gittutorial-2(7), giteveryday(7), gitcvs-migration(7), gitglossary(7), gitcore-tutorial(7), gitcli(7), The Git User’s Manual[1], gitworkflows(7) Especially

Posted by Marcus Folkesson on Monday, October 2, 2023

Support for CRIU in Buildroot

Support for CRIU in Buildroot A couple of months ago I started to evaluate [1] CRIU [2] for a project I'm working on. The project itself is using Buildroot to build and generate the root filesystem. Unfortunately, Buildroot lacks support for CRIU so there were some work to do. To write the package was not straight forward. The package is only supported on certain architectures and the utils/test-pkg script failed for a few toolchains.

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Posted by Marcus Folkesson on Sunday, October 1, 2023

TIL - Git --color-moved

TIL - Git --color-moved TIL, Today I Learned, is more of a "I just figured this out: here are my notes, you may find them useful too" rather than a full blog post Did you know that Git is able to detect moved blocks and use different colors from the usual added/removed lines? Me neither until now. The paremeter is --color-moved and has been around since v0.4.0, so there is no new feature.

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Posted by Marcus Folkesson on Saturday, September 23, 2023

TIL - Buildroot and LIBFOO_LINUX_CONFIG_FIXUPS

TIL - Buildroot and LIBFOO_LINUX_CONFIG_FIXUPS TIL, Today I Learned, is more of a "I just figured this out: here are my notes, you may find them useful too" rather than a full blog post Some applications in a Linux system depends on certain kernel features to work properly. I'm currently working on adding support for CRIU [1] in Buildroot [2] which has such requirements. That's when I stumble upon the LIBFOO_LINUX_CONFIG_FIXUP variable.

Posted by Marcus Folkesson on Tuesday, September 12, 2023