Re: Raspberry Pi POE+ hat overlay

From: Mark Millard <marklmi_at_yahoo.com>
Date: Fri, 12 May 2023 17:11:06 UTC
On May 12, 2023, at 09:38, Doug Rabson <dfr@rabson.org> wrote:

> On Fri, 12 May 2023 at 17:27, Mark Millard <marklmi@yahoo.com> wrote:
> On May 12, 2023, at 08:43, Doug Rabson <dfr@rabson.org> wrote:
> 
> > I have a pi4 with the official POE+ hat which I want to run FreeBSD on. One thing I noticed is that the fan doesn't run in FreeBSD so I decided to try and write a little driver for it. First step seems to be to load the corresponding devicetree overlay by adding something like this to /boot/msdos/config.txt:
> > 
> > dtoverlay=rpi-poe-plus
> > dtparam=poe_fan_temp0=45000,dtparam=poe_fan_temp0_hyst=3000
> > dtparam=poe_fan_temp1=50000,dtparam=poe_fan_temp1_hyst=3000
> > dtparam=poe_fan_temp2=62000,dtparam=poe_fan_temp2_hyst=4000
> > dtparam=poe_fan_temp3=70000,dtparam=poe_fan_temp3_hyst=5000
> > 
> > Unfortunately this is where I'm stuck - the overlay is not present in the final DTB given to the kernel so there isn't anything to hook a driver to. Are dtoverlays supposed to work on FreeBSD?
> 
> The RPi* firwmare version that FreeBSD has in ports and uses
> in making snapshots and other images does not have that overlay:
> 
> # ls -Tld /usr/local/share/rpi-firmware/overlays/rpi*
> -rw-r--r--  1 root  wheel   489 Mar  3 05:29:57 2021 /usr/local/share/rpi-firmware/overlays/rpi-backlight.dtbo
> -rw-r--r--  1 root  wheel  4081 Mar  3 05:29:57 2021 /usr/local/share/rpi-firmware/overlays/rpi-cirrus-wm5102.dtbo
> -rw-r--r--  1 root  wheel   643 Mar  3 05:29:57 2021 /usr/local/share/rpi-firmware/overlays/rpi-dac.dtbo
> -rw-r--r--  1 root  wheel  2574 Mar  3 05:29:57 2021 /usr/local/share/rpi-firmware/overlays/rpi-display.dtbo
> -rw-r--r--  1 root  wheel   842 Mar  3 05:29:57 2021 /usr/local/share/rpi-firmware/overlays/rpi-ft5406.dtbo
> -rw-r--r--  1 root  wheel  2937 Mar  3 05:29:57 2021 /usr/local/share/rpi-firmware/overlays/rpi-poe.dtbo
> -rw-r--r--  1 root  wheel   771 Mar  3 05:29:57 2021 /usr/local/share/rpi-firmware/overlays/rpi-proto.dtbo
> -rw-r--r--  1 root  wheel   893 Mar  3 05:29:57 2021 /usr/local/share/rpi-firmware/overlays/rpi-sense.dtbo
> -rw-r--r--  1 root  wheel   567 Mar  3 05:29:57 2021 /usr/local/share/rpi-firmware/overlays/rpi-tv.dtbo
> -rw-r--r--  1 root  wheel  1226 Mar  3 05:29:57 2021 /usr/local/share/rpi-firmware/overlays/rpivid-v4l2.dtbo
> 
> You do not mention establishing a copy of overlays/rpi-poe-plus.dtbo .
> 
> I copied the file from a rasbian install I had for another project. Perhaps I should find the corresponding source for it and build it with the device tree source from FreeBSD.
>   
> You also do not mention what version of FreeBSD you are using
> on the RPi4B. The output of the command:
> 
> I'm running 13.2-RELEASE-p0

That limits the range of firmware you can experiment with
but the following tagged vintages should be compatible and
also have an overlays/rpi-poe-plus.dtbo present:

1.20210527/boot/overlays/rpi-poe-plus.dtbo
1.20210727/boot/overlays/rpi-poe-plus.dtbo
1.20210805/boot/overlays/rpi-poe-plus.dtbo

So extracting a consistent/full set of firmware and trying
it is a possibility.

The first 3 tags links on:

https://github.com/raspberrypi/linux/tags?after=1.20210831

are for the above 3 firmware versions.

Anything newer will lead to a FreeBSD kernel crash for
13.2-RELEASE-p0 due to mishandling the .dtb file that
would be used.

As an example of what is in . . ./boot/ from one of those 3:

# ls -Tld firmware-1.20210805/boot/*
-rw-rw-r--  1 root  wheel    18693 Aug  5 04:11:18 2021 firmware-1.20210805/boot/COPYING.linux
-rw-rw-r--  1 root  wheel     1594 Aug  5 04:11:18 2021 firmware-1.20210805/boot/LICENCE.broadcom
-rw-rw-r--  1 root  wheel    26401 Aug  5 04:11:18 2021 firmware-1.20210805/boot/bcm2708-rpi-b-plus.dtb
-rw-rw-r--  1 root  wheel    25749 Aug  5 04:11:18 2021 firmware-1.20210805/boot/bcm2708-rpi-b-rev1.dtb
-rw-rw-r--  1 root  wheel    26138 Aug  5 04:11:18 2021 firmware-1.20210805/boot/bcm2708-rpi-b.dtb
-rw-rw-r--  1 root  wheel    26060 Aug  5 04:11:18 2021 firmware-1.20210805/boot/bcm2708-rpi-cm.dtb
-rw-rw-r--  1 root  wheel    27076 Aug  5 04:11:18 2021 firmware-1.20210805/boot/bcm2708-rpi-zero-w.dtb
-rw-rw-r--  1 root  wheel    25883 Aug  5 04:11:18 2021 firmware-1.20210805/boot/bcm2708-rpi-zero.dtb
-rw-rw-r--  1 root  wheel    27276 Aug  5 04:11:18 2021 firmware-1.20210805/boot/bcm2709-rpi-2-b.dtb
-rw-rw-r--  1 root  wheel    27425 Aug  5 04:11:18 2021 firmware-1.20210805/boot/bcm2710-rpi-2-b.dtb
-rw-rw-r--  1 root  wheel    29542 Aug  5 04:11:18 2021 firmware-1.20210805/boot/bcm2710-rpi-3-b-plus.dtb
-rw-rw-r--  1 root  wheel    28923 Aug  5 04:11:18 2021 firmware-1.20210805/boot/bcm2710-rpi-3-b.dtb
-rw-rw-r--  1 root  wheel    27421 Aug  5 04:11:18 2021 firmware-1.20210805/boot/bcm2710-rpi-cm3.dtb
-rw-rw-r--  1 root  wheel    49825 Aug  5 04:11:18 2021 firmware-1.20210805/boot/bcm2711-rpi-4-b.dtb
-rw-rw-r--  1 root  wheel    49821 Aug  5 04:11:18 2021 firmware-1.20210805/boot/bcm2711-rpi-400.dtb
-rw-rw-r--  1 root  wheel    50499 Aug  5 04:11:18 2021 firmware-1.20210805/boot/bcm2711-rpi-cm4.dtb
-rw-rw-r--  1 root  wheel    52456 Aug  5 04:11:18 2021 firmware-1.20210805/boot/bootcode.bin
-rw-rw-r--  1 root  wheel     7278 Aug  5 04:11:18 2021 firmware-1.20210805/boot/fixup.dat
-rw-rw-r--  1 root  wheel     5407 Aug  5 04:11:18 2021 firmware-1.20210805/boot/fixup4.dat
-rw-rw-r--  1 root  wheel     3211 Aug  5 04:11:18 2021 firmware-1.20210805/boot/fixup4cd.dat
-rw-rw-r--  1 root  wheel     8416 Aug  5 04:11:18 2021 firmware-1.20210805/boot/fixup4db.dat
-rw-rw-r--  1 root  wheel     8418 Aug  5 04:11:18 2021 firmware-1.20210805/boot/fixup4x.dat
-rw-rw-r--  1 root  wheel     3211 Aug  5 04:11:18 2021 firmware-1.20210805/boot/fixup_cd.dat
-rw-rw-r--  1 root  wheel    10262 Aug  5 04:11:18 2021 firmware-1.20210805/boot/fixup_db.dat
-rw-rw-r--  1 root  wheel    10262 Aug  5 04:11:18 2021 firmware-1.20210805/boot/fixup_x.dat
drwxrwxr-x  2 root  wheel      236 Aug  5 04:11:18 2021 firmware-1.20210805/boot/overlays
-rw-rw-r--  1 root  wheel  2959904 Aug  5 04:11:18 2021 firmware-1.20210805/boot/start.elf
-rw-rw-r--  1 root  wheel  2235712 Aug  5 04:11:18 2021 firmware-1.20210805/boot/start4.elf
-rw-rw-r--  1 root  wheel   799964 Aug  5 04:11:18 2021 firmware-1.20210805/boot/start4cd.elf
-rw-rw-r--  1 root  wheel  3731528 Aug  5 04:11:18 2021 firmware-1.20210805/boot/start4db.elf
-rw-rw-r--  1 root  wheel  2987720 Aug  5 04:11:18 2021 firmware-1.20210805/boot/start4x.elf
-rw-rw-r--  1 root  wheel   799964 Aug  5 04:11:18 2021 firmware-1.20210805/boot/start_cd.elf
-rw-rw-r--  1 root  wheel  4803496 Aug  5 04:11:18 2021 firmware-1.20210805/boot/start_db.elf
-rw-rw-r--  1 root  wheel  3711432 Aug  5 04:11:18 2021 firmware-1.20210805/boot/start_x.elf

(I'll not list the overlays/* .)

I've no clue to the consequences of mixing and matching
materials from different vintages of the firmware. It
does appear that:

1.20210727/boot/overlays/rpi-poe-plus.dtbo
1.20210805/boot/overlays/rpi-poe-plus.dtbo

(the newer 2 of th3 3) are the same by content but that:

1.20210527/boot/overlays/rpi-poe-plus.dtbo

is distinct in its older content.

===
Mark Millard
marklmi at yahoo.com