LinuxCNC on Raspberry Pi 4

tjmarch wrote:

Was just wondering if you were able to update cpuinfo.c 

The problem is more complicated than I thought and it's not just about cpuinfo.c and I think it's due to the new kernel you use:

kernel-vers -v: # 1 SMP PREEMPT_RT Debian 6.0.5-1 (2022-10-28)

In fact, to temporarily overcome the problem I copied the file / proc / cpuinfo in / tmp with the following command
cp /proc/cpuinfo /tmp/cpuinfo.txt

I added the following string at the end of the file

Revision: c03112

and then I used the following command

mount --bind /tmp/cpuinfo.txt /proc/cpuinfo

At this point, however, the error has changed and is related to the hal_pi_gpio.c module

pi@raspberrypi:~ $ halrun -I
halcmd: loadrt hal_pi_gpio
Note: Using POSIX realtime
HAL_PI_GPIO: can't open /dev/gpiomem: 2 - No such file or directory
If the error is 'permission denied' then try adding the user who runs
LinuxCNC to the gpio group: sudo gpasswd -a username gpio
HAL_PI_GPIO: can't open /dev/mem: 13 - Permission denied
hal_pi_gpio: rtapi_app_main: Operation not permitted (-1)
<stdin>:1: waitpid failed /usr/bin/rtapi_app hal_pi_gpio
<stdin>:1: /usr/bin/rtapi_app exited without becoming ready
<stdin>:1: insmod for hal_pi_gpio failed, returned -1
halcmd: exit
Note: Using POSIX realtime

I tried as superuser but again a new error occurred

pi@raspberrypi:~ $ sudo halrun -I
halcmd: loadrt hal_pi_pio
Refusing to run as root without fallback UID specified
To run under a debugger with I/O, use e.g.,
sudo env RTAPI_UID=`id -u` RTAPI_FIFO_PATH=$HOME/.rtapi_fifo gdb /usr/bin/rtapi_app
<stdin>:1: waitpid failed /usr/bin/rtapi_app hal_pi_pio
<stdin>:1: /usr/bin/rtapi_app exited without becoming ready
<stdin>:1: insmod for hal_pi_pio failed, returned -1
halcmd: exit
Refusing to run as root without fallback UID specified
To run under a debugger with I/O, use e.g.,
sudo env RTAPI_UID=`id -u` RTAPI_FIFO_PATH=$HOME/.rtapi_fifo gdb /usr/bin/rtapi_app
pi@raspberrypi:~ $

I am therefore trying to figure out how to deal with the problem which I hope will be solved by a kernel update

To elovalvo,
Made a little progress was able to downgrade kernel to 5.15.65-rt49-v8+
from github.com/kdoren/linux/releases.
To do this I installed deb files then I copied initrd.img-5.15.65-rt49-v8+ and vmlinuz-5.15.65-rt49-v8+ from /boot to /boot/firmware.
Then made appropriate changes to /boot/firmware/config.txt
This eliminated  original problem of not recognizing rpi board.
After reading this at roboticsbackend.com/raspberry-pi-hardware-permissions/
Then I added file /etc/udev/rules.d/local.rules with the following;
ACTION=="add", KERNEL=="mem", MODE="0666"
This got ride of permission problem for memory.
Now linuxcnc will start but still with error which I think goose back to
HAL_PI_GPIO: can't open /dev/gpiomem: 2 - No such file or directory

If you open terminal then
cd /dev
ls -l | more

you will see that there is no /dev/gpiomem
just gpiochip0 and gpiochip1

 

To elovalvo,
After closer inspection of HAL  pins that were created gpio pins were created correctly

 

tjmarch wrote:

To elovalvo,
Made a little progress was able to downgrade kernel to 5.15.65-rt49-v8+
from github.com/kdoren/linux/releases.
To do this I installed deb files then I copied initrd.img-5.15.65-rt49-v8+ and vmlinuz-5.15.65-rt49-v8+ from /boot to /boot/firmware.
Then made appropriate changes to /boot/firmware/config.txt
This eliminated  original problem of not recognizing rpi board.
After reading this at roboticsbackend.com/raspberry-pi-hardware-permissions/
Then I added file /etc/udev/rules.d/local.rules with the following;
ACTION=="add", KERNEL=="mem", MODE="0666"
This got ride of permission problem for memory.
Now linuxcnc will start but still with error which I think goose back to
HAL_PI_GPIO: can't open /dev/gpiomem: 2 - No such file or directory

If you open terminal then
cd /dev
ls -l | more

you will see that there is no /dev/gpiomem
just gpiochip0 and gpiochip1

Unfortunately, despite many attempts, I have not been able to solve the problem.
I believe this is due to the new kernel version 6.0.5-1 (2022-10-28) that you are using.

As the full working version (5.15.65-rt49-v8+), based on Raspbian rather than Debian, is available here
forum.linuxcnc.org/9-installing-linuxcnc...cnc?start=150#253623
why do you want to use Debian? To switch to Bookworm?

tjmarch wrote:

To elovalvo,
...........
This got ride of permission problem for memory.
Now linuxcnc will start but still with error which I think goose back to
HAL_PI_GPIO: can't open /dev/gpiomem: 2 - No such file or directory

If you open terminal then
cd /dev
ls -l | more

you will see that there is no /dev/gpiomem
just gpiochip0 and gpiochip1

Going to sift through my notes, I found that, as reported in this link (forum.linuxcnc.org/9-installing-linuxcnc...-debian-64bit#178472), in this link (forum.linuxcnc.org/9-installing-linuxcnc...-debian-64bit#158905 that you modified on 17/4/2021) there was a file (services or linuxcnc-mem-services.zip) that would solve the problem you indicated

In particular, I found these instructions


Do you have a chance to recover this file?

To elovalvo,
I deleted that post along with the files I had a long time ago, sorry. But those file would not have gotten rid of the problem of /dev/gpiomem because /dev/gpiomem dose not exsist on the version of debian that is in development for raspberry pi now. But Rasbian still uses /dev/gpiomem. The probem with reconizing the board can be overcome with using the kernel from   github.com/kdoren/linux/releases  . I also came up with a fix for /dev/mem useage from this artical   roboticsbackend.com/raspberry-pi-hardware-permissions/
Then I added file /etc/udev/rules.d/local.rules with the following;
ACTION=="add", KERNEL=="mem", MODE="0666"
This got ride of permission problem for /dev/mem. What I think needs to happen is the Hal_pi_gpio driver needs to be updated to not use /dev/gpiomem when used with pure Debian OS. 

Regards
Tim

So, where is this at? Is there a version of LinucCNC that works on the new rev of RPi 4?

dannym wrote:

So, where is this at? Is there a version of LinucCNC that works on the new rev of RPi 4?

If you are looking for a ready-made image, tested with Rasperry Pi 4B (2GB and 4GB) and Pi400, you can find:

- the Buster-based 32bit version with LinuxCNC 2.8.4 here
forum.linuxcnc.org/9-installing-linuxcnc...erry-pi-3b-pi#260915

- the Buster-based 64bit version with LinuxCNC 2.8.2 here
forum.linuxcnc.org/9-installing-linuxcnc...-4-8gb-2gb?start=50# 255092

- the 64bit version based on Bullseye with LinuxCNC 2.9.0pre here
forum.linuxcnc.org/9-installing-linuxcnc...cnc?start=150#253623

Also there are numerous links on the forum describing how to create your own image on different distributions (Raspi OS, Debian, Ubuntu, etc):

forum.linuxcnc.org/9-installing-linuxcnc...c-2-9-on-rpi4#260565
forum.linuxcnc.org/9-installing-linuxcnc...mpt-rt-kernel#259347
forum.linuxcnc.org/9-installing-linuxcnc...ethercat-xfce#243060
forum.linuxcnc.org/9-installing-linuxcnc...-bit-linuxcnc#230690

If you wait a few days, I'm preparing an experimental one with 64 bit, with Debian 11 (Linux 6.0.09-rt14) and LinuxCNC 2.10.0pre

>- the Buster-based 64bit version with LinuxCNC 2.8.2 here

But that's the one that just says "this board requires newer software" and won't boot with the current rev of RPI 4 board.

>- the 64bit version based on Bullseye with LinuxCNC 2.9.0pre here
forum.linuxcnc.org/9-installing-linuxcnc...cnc?start=150#253623

And this one says "Welcome to Raspberry Pi Desktop" splash screen, but then the monitor says the HDMI signal is lost and it never recovers. Hitting the keyboard had no effect.