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