S32G2 Linux LLCE debugfs interface

[m_bez]

I'm trying to set up LLCE filters to route some messages on can10 to can11, and route other messages to the host.

First, I would like to ask where the documentation for the debugfs interface is. There is an example in the S32G2_LinuxBSP_42.0_User_Manual.pdf, and modifying this allows the creation of filters between interfaces. However, I'm not sure how to create a filter that uses a mask or ID to send some traffic to the Linux host.

The file /sys/kernel/debug/llce_can_core/can_destinations/add/README refers to the LLCE Firmware User Guide. Where can I find this document, or perhaps some more examples of LLCE filter configurations?

[m_bez]

I've looked at the firmware user guide, but I can't see any reference to the debugfs interface. Specifically, I'm having trouble creating a filter that sends traffic to the host, based on a mask, without forwarding that traffic to a different interface. This should be possible, since such filters are the ones set up by default:

```
oot@s32g274a-n4c0a53:~# cat /sys/kernel/debug/llce_can_core/can_filters/list
hw_ctrl status can_mask_id msg_id tag mb_count addr rx_intf entry mb_type | opt_auth opt_host
logging opt_custom can_dest
0 enabled 0x00000000 0x00000000 0x0000 0x0010 512 15 mask long |
1 enabled 0x00000000 0x00000000 0x0001 0x0010 513 14 mask long |
2 enabled 0x00000000 0x00000000 0x0002 0x0010 514 13 mask long |
3 enabled 0x00000000 0x00000000 0x0003 0x0010 515 12 mask long |
4 enabled 0x00000000 0x00000000 0x0004 0x0010 516 11 mask long |
5 enabled 0x00000000 0x00000000 0x0005 0x0010 517 10 mask long |
6 enabled 0x00000000 0x00000000 0x0006 0x0010 518 9 mask long |
7 enabled 0x00000000 0x00000000 0x0007 0x0010 519 8 mask long |
8 enabled 0x00000000 0x00000000 0x0008 0x0010 520 7 mask long |
9 enabled 0x00000000 0x00000000 0x0009 0x0010 521 6 mask long |
10 enabled 0x00000000 0x00000000 0x010a 0x0010 522 5 mask short |
11 enabled 0x00000000 0x00000000 0x010b 0x0010 523 4 mask short |
```

But I need to create a filter similar to these, only with a mask other than 0x00000000

[carlos_o]

Hi @m_bez,

Please refer to the chapter 12.3.5.1 CAN2CAN demo of the BSP User Manual.

There is an example adding a filter with a custom msg_id.

Screenshot 2025-02-06 135518.png

[Page 104, Linux BSP 42.0 User Manual for S32G2 platforms] 

[m_bez]

Yes, this is the interface I'm having trouble with. I have some questions about that example

First, how do I set up the filter to communicate with the host linux system? How do I configure the lice_can_destination to not use a different CAN interface?

Second, if I were to use another channel to achieve the same, and I set opt_host to I, then the first message behaves as expected, but then no messages get forwarded, and I start getting bus errors after 16 messages

[carlos_o]

Hi @m_bez,

I found the following information used as example for this:

"

# llcecan link up
ip link set up llcecan14 type can bitrate 500000 dbitrate 5000000 fd on
ip link set up llcecan15 type can bitrate 500000 dbitrate 5000000 fd on

# disable current basic filter
echo disabled > /sys/kernel/debug/llce_can_core/can_filters/set_status/status
echo 512 > /sys/kernel/debug/llce_can_core/can_filters/set_status/addr
echo 1 > /sys/kernel/debug/llce_can_core/can_filters/set_status/execute
echo 513 > /sys/kernel/debug/llce_can_core/can_filters/set_status/addr
echo 1 > /sys/kernel/debug/llce_can_core/can_filters/set_status/execute

# llcecan14 basic filter

echo 0xFF > /sys/kernel/debug/llce_can_core/can_filters/add/can_dest
echo 0x7F0 > /sys/kernel/debug/llce_can_core/can_filters/add/can_mask_id
echo mask > /sys/kernel/debug/llce_can_core/can_filters/add/entry
echo 14 > /sys/kernel/debug/llce_can_core/can_filters/add/hw_ctrl
echo 0xe > /sys/kernel/debug/llce_can_core/can_filters/add/tag
echo 0x10 > /sys/kernel/debug/llce_can_core/can_filters/add/mb_count
echo long > /sys/kernel/debug/llce_can_core/can_filters/add/mb_type
echo 0x543 > /sys/kernel/debug/llce_can_core/can_filters/add/msg_id
echo enabled > /sys/kernel/debug/llce_can_core/can_filters/add/status
echo disabled > /sys/kernel/debug/llce_can_core/can_filters/add/opt_auth
echo disabled > /sys/kernel/debug/llce_can_core/can_filters/add/opt_custom
echo disabled > /sys/kernel/debug/llce_can_core/can_filters/add/opt_host
echo disabled > /sys/kernel/debug/llce_can_core/can_filters/add/logging
echo 1 > /sys/kernel/debug/llce_can_core/can_filters/add/execute

candump any,0:0,#FFFFFFFF >log &

# accepted
cansend llcecan15 546#22335566

#discarded
cansend llcecan15 556#22335566

"

About your first questions. Do you want the filter only to communicate with the host? or communicate with the host and simultaneously send it to another llce_can?

Could you explain in more detail the behavior of your second question?

[m_bez]

Hey @carlos_o , thanks for the help.

> I found the following information used as example for this:
I'll work through the example, but it looks like OPT_HOST is disabled, and the previeous example you gave indicates that this disables host communication

> Do you want the filter only to communicate with the host
Some Addresses need to be sent to the host

> or communicate with the host and simultaneously send it to another llce_can?
All other traffic not sent to the host should be sent to another interface.

> Could you explain in more detail the behavior of your second question?
The filter and host are set up as follows:
```
hw_ctrl status can_mask_id msg_id tag mb_count addr rx_intf entry mb_type | opt_auth opt_host logging opt_custom can_dest
10 disabled 0x00000000 0x00000000 0x0000 0x0010 524 5 mask short | disabled enabled disabled disabled 0
id routing_opts can_id_remap ch_list
0 0x00000000 0x00000000 11
```
If I send a single message to can10, it gets routed to can 11, as well as the host. Messages after that do not get routed. After I've sent 16 messages without one being delivered, the can interface on the host starts reporting a bus error every time I send a message.

[carlos_o]

Hi @m_bez,

The example only is for reference to how to configure the filters.

Thanks for clarifying your goal with the filters, let me know the results you get and if it solves the problem with the bus error msg. 

[m_bez]

> The example only is for reference
Tee example doesn't include the creation of destinations, does this still need to happen? or is destination 0xFF created by default?
> let me know the results
The value of the mask_id (0x7F) doesn't make sense to me. How does it relate to the addresses being filtered? All other parameters in the example make sense to me, and are already how I configure the filters, but it has no host communication.

[carlos_o]

Hi @m_bez,

Q: Tee example doesn't include the creation of destinations, does this still need to happen? or is destination 0xFF created by default?

A: Yes, you still need to create a destination.

Q: The value of the mask_id (0x7F) doesn't make sense to me. How does it relate to the addresses being filtered? All other parameters in the example make sense to me, and are already how I configure the filters, but it has no host communication.

A: This mask_id is only an example and work as if you put a mask id in a CAN communication to take some action when a msg arrive with some id that pass the mask. 

Also, to enable the communication with the host you only need to set the opt_host config to "enable" 

All the subdirectories at the /sys/kernel/debug/llce_can_core/ have a README file that explain the possible configurations. 

[m_bez]

Thanks for your response. However, setting opt_host to "enabled" causes unexpected behavior as described earlier. Specifically, when opt_host is enabled, the first message behaves as expected, but subsequent messages do not get forwarded, and after 16 messages, the CAN interface on the host starts reporting bus errors.

Could you provide more detailed guidance on how to configure the filter to communicate with the host without causing these issues?

[carlos_o]

Hi @m_bez, 

It seems like the filter status of your filter is disable. Could you please enable it with "echo enabled > /sys/kernel/debug/llce_can_core/can_filters/add/status"?

Retry to send the data after that and let me know the results. 

[m_bez]

hey @carlos_o, if I set the filter explicitly to enabled before executing, I get a permission error trying to write to the file
`/sys/kernel/debug/llce_can_core/can_filters/add/set_status: Permission denied`
If I list the filters after, they seem to be enumerated as enabled in any case
```
root@s32g274a-n4c0a53:~# cat /sys/kernel/debug/llce_can_core/can_filters/list
hw_ctrl status can_mask_id msg_id tag mb_count addr rx_intf entry mb_type | opt_auth opt_host
logging opt_custom can_dest
0 enabled 0x00000000 0x00000000 0x0000 0x0010 512 15 mask long |

1 enabled 0x00000000 0x00000000 0x0001 0x0010 513 14 mask long |

2 enabled 0x00000000 0x00000000 0x0002 0x0010 514 13 mask long |
3 enabled 0x00000000 0x00000000 0x0003 0x0010 515 12 mask long |
4 enabled 0x00000000 0x00000000 0x0004 0x0010 516 11 mask long |
5 enabled 0x00000000 0x00000000 0x0005 0x0010 517 10 mask long |
6 enabled 0x00000000 0x00000000 0x0006 0x0010 518 9 mask long |
7 enabled 0x00000000 0x00000000 0x0007 0x0010 519 8 mask long |
8 enabled 0x00000000 0x00000000 0x0008 0x0010 520 7 mask long |
9 enabled 0x00000000 0x00000000 0x0009 0x0010 521 6 mask long |
10 disabled 0x00000000 0x00000000 0x010a 0x0010 522 5 mask short |
11 disabled 0x00000000 0x00000000 0x010b 0x0010 523 4 mask short |
10 enabled 0x00000000 0x00000000 0x0000 0x0010 524 5 mask short | disabled enabled disabled disabled 0
11 enabled 0x00000000 0x00000000 0x0000 0x0010 525 4 mask short | disabled enabled disabled disabled 1

```

Setting the status works, if I write, the address, "disabled" and execute into the respective files in `/sys/kernel/debug/llce_can_core/can_filters/set_status`, then the status visibly changes form 'enabled' to 'disabled' when I list the filters.

Enabling and disabling the filter doesn't seem to affect the behvior initially. It still only forwards a single message and reports bus errors after 16 messages. Once it starts reporting bus errors, disabling and enabling the filter doesn't make it forward a single message again. That only happens if I reboot and reconfigure the filter.

[m_bez]

Some more info that might be of use, the errors that get generated increment the values in
/sys/class/net/llcecan10/statistics/rx_dropped
and
/sys/class/net/llcecan10/statistics/rx_errors

For the two llcecan interfaces in question.

[carlos_o]

Hi @m_bez,

The Internal team shares the following example of the complete configuration of a filter:

# llcecan link up
ip link set up llcecan14 type can bitrate 500000 dbitrate 5000000 fd on
ip link set up llcecan15 type can bitrate 500000 dbitrate 5000000 fd on

# disable current basic filter
echo disabled > /sys/kernel/debug/llce_can_core/can_filters/set_status/status
echo 512 > /sys/kernel/debug/llce_can_core/can_filters/set_status/addr
echo 1 > /sys/kernel/debug/llce_can_core/can_filters/set_status/execute
echo 513 > /sys/kernel/debug/llce_can_core/can_filters/set_status/addr
echo 1 > /sys/kernel/debug/llce_can_core/can_filters/set_status/execute

# llcecan14 basic filte

echo 0xFF >  /sys/kernel/debug/llce_can_core/can_filters/add/can_dest
echo 0x7F0 > /sys/kernel/debug/llce_can_core/can_filters/add/can_mask_id
echo mask > /sys/kernel/debug/llce_can_core/can_filters/add/entry
echo 14 > /sys/kernel/debug/llce_can_core/can_filters/add/hw_ctrl
echo 0xe > /sys/kernel/debug/llce_can_core/can_filters/add/tag
echo 0x10 > /sys/kernel/debug/llce_can_core/can_filters/add/mb_count
echo long > /sys/kernel/debug/llce_can_core/can_filters/add/mb_type
echo 0x540 > /sys/kernel/debug/llce_can_core/can_filters/add/msg_id
echo enabled > /sys/kernel/debug/llce_can_core/can_filters/add/status
echo 1 > /sys/kernel/debug/llce_can_core/can_filters/add/execute

After executing the above command, a filter as shown below will be created.

carlos_o_0-1739988050013.png

# Create a destination to be used for LLCE CAN14→LLCE CAN15 route.
echo 0x0 > /sys/kernel/debug/llce_can_core/can_destinations/add/can_id_remap
echo 15 > /sys/kernel/debug/llce_can_core/can_destinations/add/ch_list
echo 0x1 > /sys/kernel/debug/llce_can_core/can_destinations/add/routing_opts
echo 1 > /sys/kernel/debug/llce_can_core/can_destinations/add/execute
cat /sys/kernel/debug/llce_can_core/can_destinations/add/execute > \
/sys/kernel/debug/llce_can_core/can_filters/add/can_dest
echo 0x7F0 > /sys/kernel/debug/llce_can_core/can_filters/add/can_mask_id
echo mask > /sys/kernel/debug/llce_can_core/can_filters/add/entry
echo 14 > /sys/kernel/debug/llce_can_core/can_filters/add/hw_ctrl
echo 0xe > /sys/kernel/debug/llce_can_core/can_filters/add/tag
echo 0x10 > /sys/kernel/debug/llce_can_core/can_filters/add/mb_count
echo long > /sys/kernel/debug/llce_can_core/can_filters/add/mb_type
echo 0x530 > /sys/kernel/debug/llce_can_core/can_filters/add/msg_id
echo enabled > /sys/kernel/debug/llce_can_core/can_filters/add/status
echo disabled > /sys/kernel/debug/llce_can_core/can_filters/add/opt_auth
echo disabled > /sys/kernel/debug/llce_can_core/can_filters/add/opt_custom
echo disabled > /sys/kernel/debug/llce_can_core/can_filters/add/opt_host
echo disabled > /sys/kernel/debug/llce_can_core/can_filters/add/logging
echo 1 > /sys/kernel/debug/llce_can_core/can_filters/add/execute

After executing the above command, an additional filter will be created as shown in the figure below.

carlos_o_1-1739988082656.png

You need to disable the unused filters in the filter list to prevent interference between filters. After testing, the first filter will receive IDs between 0x540~0x54F to the host, and route IDs between 0x530~0x53F to llcecan15. If you need a CAN frame to be received by the host and routed to another channel at the same time, opt_host enable of the corresponding filter is required.

[m_bez]

Hey @carlos_o 

Thank you very much, this is very helpful, I'm happy to report that the filter is added to the list as expected. However, the filter doesn't work. As a sanity check, I've created a filter that exactly replicates the default one, with a mask of 0x000000. When I do this, I get traffic on the interface before I recreate the filter, but nothing after. I don't see any values increasing in `/sys/class/net/llcecan10/statistics/` that would indicate an error.
Due to hardware constraints, I'm using different interfaces (llcecan10 and llcecan11), and normal CAN in stead of canFD, so I've needed to change the example slightly. I'm attaching the script I'm using to test this. Could you please check if I'm making some mistake, or if the behavior is indeed unexpected.

I also tried to create an exact matching filter, for address 0x77, from the example in the documentation, but the interface just stops receiving communication.

the interface is up when I check `ip link show`, and if I do `cansend 000#AABBCCDD` the interface is able to send frames correctly. It just stops receiving frames once I create the basic filter that is exactly the same as the default filter:

```

root@s32g274a-n4c0a53:~# cat /sys/kernel/debug/llce_can_core/can_filters/list
hw_ctrl status can_mask_id msg_id tag mb_count addr rx_intf entry mb_type | opt_auth opt_host logging opt_custom can_dest
0 enabled 0x00000000 0x00000000 0x0000 0x0010 512 15 mask long |
[...]
8 enabled 0x00000000 0x00000000 0x0008 0x0010 520 7 mask long |
9 enabled 0x00000000 0x00000000 0x0009 0x0010 521 6 mask long |
10 enabled 0x00000000 0x00000000 0x010a 0x0010 522 5 mask short |
11 disabled 0x00000000 0x00000000 0x010b 0x0010 523 4 mask short |
11 enabled 0x00000000 0x00000000 0x000e 0x0010 524 4 mask short |

```

Another question about the example, could you please explain the 0x7F0 values that get written to /sys/kernel/debug/llce_can_core/can_filters/add/can_mask_id for both filters?

[carlos_o]

Hi @m_bez,

great to hear that you were able to configure the filter. 

Could you please share a log file with an example of the error you are getting? 

[m_bez]

Hey @carlos_o ,

I'm not getting an error per sé, the llececan interface just stops receiving packets after I've created the filter. The script I've attached runs fine without any errors, but then the output of
"candump any,0:0,#FFFFFFFF" gives no output, whereas before running the script it was printing whatever was on the bus.
I specifically checked for network errors in `/sys/class/net/llcecan10/statistics/`, but there are none.

[carlos_o]

Hi @m_bez,

Could you please help me with a step-by-step to reproduce the issue?

This to the objective to reproduce the issue at my end. 

[m_bez]

Hey @carlos_o, sure thing!

1) modify the llcecan11 line in `/etc/llce_config/llce_init.sh` to be `ip link set up llcecan11 type can bitrate 500000`
2) With another CAN device, connect to llce11. I'm using a laptop with ubuntu 24.04 and a PEAK-USB device.
3) From the other device, send some can traffic to the S32 device. In my case, the commands on the laptop are:
`sudo ip link set up can1 up type can bitrate 500000`
`cansend can0 000#deadbeef`
4) on the S32, confirm that the can messages are being received using `candump any,0:0,#FFFFFFFF`
5) on the S32, run the script called `setup_llce_NXP_Example.sh`. It's the same as one attached to an earlier post in this discussion
6) inspect `/sys/kernel/debug/llce_can_core/can_filters/list` to see that the original filter on llcecan11 was disabled, and a new, identical filter was created by the script.
7) After running the script, do ``candump any,0:0,#FFFFFFFF`` again.
from the laptop, send some more CAN traffic
9) On my device the CAN traffic is not received after running the script, while I expect it to be.
I'm attaching the script again, as well as a screenshot of the two terminal sessions, for clarity. The top terminal is the laptop, and the bottom one is an SSH session to the S32 device.

[carlos_o]

Hi @m_bez, 

I notice as you say in this thread that the filter that you are setting does not have another destination, why you did not put HIF (host interface) as destination?

Screenshot 2025-02-27 181100.png

In this case the error can be because the can destination you are setting is not initialized. Another option can be initializing another llce can interface and put it as destination of the filter. 

[m_bez]

Hey @carlos_o 

I've described the behavior when I use a different destination already:

> The filter and host are set up as follows:
```
hw_ctrl status can_mask_id msg_id tag mb_count addr rx_intf entry mb_type | opt_auth opt_host logging opt_custom can_dest
10 disabled 0x00000000 0x00000000 0x0000 0x0010 524 5 mask short | disabled enabled disabled disabled 0
id routing_opts can_id_remap ch_list
0 0x00000000 0x00000000 11
```
>If I send a single message to can10, it gets routed to can 11, as well as the host. Messages after that do not get routed. After I've sent 16 messages without one being delivered, the can interface on the host starts reporting a bus error every time I send a message.

To put 'HIF' as destination is unclear to me. I'm unable to write `HIF` into /sys/kernel/debug/llce_can_core/can_filters/add/can_dest
-sh: echo: write error: Invalid argument