Marcus Folkesson

Embedded Linux Artist

TIL - strace and capabilites

TIL - strace and capabilities 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 strace [1] is a terrific tool to trace system calls and signals for a specific command. The fact that programs using the setuid bit do not have the effective user ID priviliges when being traced was something I already knew, but that the same was true to capabilites [2] was new to me.

Posted by Marcus Folkesson on Sunday, September 8, 2024

TIL - interactive shell script

TIL - interactive shell script 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 Tody I saw this line in a script: 1INTERACTIVE="" && [[ -t 0 ]] && INTERACTIVE="-it" that later on started a container: 1docker run --rm ${INTERACTIVE} -v "${PWD}":/home/br-user \ 2 --user "$(id -u)":"$(id -g)" \ 3 myproject/docker "${@}" It tests if STDIN is opened on a terminal and in that case set $INTERACTIVE to -ti to start the container with an interactive shell.

Posted by Marcus Folkesson on Thursday, August 29, 2024

Board bring-up part 4: Wrap it up

Board bring-up part 4: Wrap it up I'm currently working with a board bring up for a custom hardware based on a OMAPL138 from Texas Instruments. It is fun to work with "real" bring-ups. Most of my customers use System On Modules (SoM:s) these days. You get a lot for free with those modules but a lot of the fun is stripped away. This post is not intended to be guide, it is more of a follow-me-through-my-work-post divided into three parts.

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Posted by Marcus Folkesson on Saturday, August 17, 2024

Board bring-up part 3: Other peripherals

Board bring-up part 3: Other peripherals I'm currently working with a board bring up for a custom hardware based on a OMAPL138 from Texas Instruments. It is fun to work with "real" bring-ups. Most of my customers use System On Modules (SoM:s) these days. You get a lot for free with those modules but a lot of the fun is stripped away. This post is not intended to be guide, it is more of a follow-me-through-my-work-post divided into three parts.

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Posted by Marcus Folkesson on Friday, August 16, 2024

Board bring-up part 2: NAND flash

Board bring-up part 2: NAND flash I'm currently working with a board bring up for a custom hardware based on a OMAPL138 from Texas Instruments. It is fun to work with "real" bring-ups. Most of my customers use System On Modules (SoM:s) these days. You get a lot for free with those modules but a lot of the fun is stripped away. This post is not intended to be guide, it is more of a follow-me-through-my-work-post divided into three parts.

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Posted by Marcus Folkesson on Thursday, August 15, 2024

Board bring-up part 1: Memory hassle

Board bring-up part 1: Memory hassle I'm currently working with a board bring up for a custom hardware based on a OMAPL138 from Texas Instruments. It is fun to work with "real" bring-ups. Most of my customers use System On Modules (SoM:s) these days. You get a lot for free with those modules but a lot of the fun is stripped away. This post is not intended to be guide, it is more of a follow-me-through-my-work-post divided into three parts.

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Posted by Marcus Folkesson on Wednesday, August 14, 2024

Forge a kitchen knife

Forge a kitchen knife Another attempt to forge a knife. The metal I use for this project is part of a feather harrow that I collected from my father farm. I cut out a ~8x4cm long piece from the springs of the feather harrow: Bosse (the dog) never leaves me, so I got him a sack to snuggle down on at the outside of the garage. I used the gas forge for the entire project.

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Posted by Marcus Folkesson on Thursday, August 1, 2024

--build, --host and --target explained

--build, --host and --target explained Too often I see abuse of the --host, --build and --target options during (cross-)compilation of code using autotools. The feeling is more that people try different values until it seems to produce what they want without knowing what they are actually doing. But who can blame them. What these parameters do it not obvious and very few people compile their own crosscompiler nowadays - or ever did.

Posted by Marcus Folkesson on Wednesday, July 17, 2024

Forge a knife blade from a car spring

Forge a knife blade from a car spring I helped my friend to change springs on his car, so I kept the broken spring as forging material. The carbon content of spring steel is aroundd 0.6 to 0.8% which works well for hardening - so lets forge a knife! I cut out a ~10cm long piece from the car spring. I use the induction heater to straight it out and flatten it a little.

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Posted by Marcus Folkesson on Sunday, July 14, 2024

OMAPL138 AIS generator

OMAPL138 AIS Generator I'm currently working on an old platform based on OMAPL138 from Texas Instruments. The OMAPL138 SoC is cool in itself, it is a ARM9 core with a C674x DSP coprocessor. My project scope is to modernize the platform to a more recent kernel/bootloader and add support for a few more interfaces due to a new HW revision. The OMAPL138 is from 2009 but still active. The latest revision for the chip (Rev.

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Posted by Marcus Folkesson on Saturday, July 13, 2024