sys/uart fdt Here is pointers to the code we should be using Hope this helps, John. FreeBSD, UART and Raspberry Pi 3 B+
Fred Finster <[email protected]>
| Newsgroups | gmane.os.freebsd.devel.arm |
|---|---|
| Message-ID | <[email protected]> |
https://blackdot.be/2018/08/freebsd-uart-and-raspberry-pi-3-b/ FreeBSD, UART and Raspberry Pi 3 B+ He also wanted to hook up a GPS input to a serial port 0. Fred If you are reading this because you, like me were lost and frustrated… I feel your pain. But let me try and help! A few weeks ago I added a POE HAT to a Raspberry Pi 3B+ and installed FreeBSD to so I could build a remote access server. I also bough another Raspberry Pi 3B+ to replace by OrangePi Zero + USB uBlox 5 NTP server. Unlike Raspbian it is surprisingly hard to stop FreeBSD’s kernel from grabbing uart0 for it’s console. Lets start with why you are probably here… how do I stop the kernel from doing this? |echo 'hw.fdt.console="NO"' >> /boot/loader.conf.local | Easy right? It took me more than 24 hours to find this. Most of which was one long Saturday. I could not find much (any) documentation on this parameter. So how did I find it? One of the embedded device devs from FreeBSD recommended to remove /chosen/stdout-path from the fdt tree. This did not work. After a few hours of messing around with building kernels without baked in uart support and other dead-ends I went back to looking at the fdt stuff. |/usr/src/sys/gnu/dts/arm/bcm2837-rpi-3-b-plus.dts /usr/src/sys/gnu/dts/arm/bcm2835-rpi.dtsi /usr/src/sys/gnu/dts/arm/bcm2837.dts | These dtsi and dts files are what eventually end up in the fdt…*bcm2837-rpi-3-b-plus.dts*holds the /chosen/stdout-path for the rPI 3B+. -- Fred Finster [email protected] +1 971-718-9144 https://GhostBSD-ARM64.blogspot.com https://ghostbsd.org