Canfd cannot reach 5Mbps

[1031150349]

I used jetpack5.1.2 to test the communication transmission of canfd. I used a self-made onboard, but when I tested it, I found that the rate could not reach 5Mbps. I measured the waveform with an oscilloscope and the maximum rate was 2.5MHz. Our hardware can support a rate of up to 5Mbps. Our software settings are as follows. I don’t know if there are other settings that are overlooked.

busybox devmem 0x0c303018 w 0xc458
busybox devmem 0x0c303010 w 0xc400  

modprobe can
modprobe can_raw
modprobe mttcan

echo 0x600 > /sys/devices/platform/c310000.mttcan/net/can0/tdc_offset

Next, I use socket can to test the sending and receiving.

[KevinFFF]

Hi 1031150349

Have you also verify on the devkit board?

How did you configure the CAN interface? Could you share the commands how did you configure it?

Is there any error showing in dmesg if you configure it with 5MHz?

[1031150349]

There is no CAN transceiver on the devkit, but our board is almost the same as the devkit.
My configuration process：

busybox devmem 0x0c303018 w 0xc458
busybox devmem 0x0c303010 w 0xc400 


modprobe can
modprobe can_raw
modprobe mttcan

echo 0x600 > /sys/devices/platform/c310000.mttcan/net/can0/tdc_offset
ip link set can0 down
ip link set can0 up type can bitrate 500000 dbitrate 5000000 berr-reporting on fd on
sudo ifconfig can0 txqueuelen 1000

ip -s -d link show can0

Then I used socketcan to test the sending and receiving speed.

I think my dmesg is normal, I captured the dmesg log after setting up can.

[   17.080367] Adding 993480k swap on /dev/zram5.  Priority:5 extents:1 across:993480k SS
[   17.081921] zram6: detected capacity change from 0 to 1017327616
[   17.112339] Adding 993480k swap on /dev/zram6.  Priority:5 extents:1 across:993480k SS
[   17.113881] zram7: detected capacity change from 0 to 1017327616
[   17.144543] Adding 993480k swap on /dev/zram7.  Priority:5 extents:1 across:993480k SS
[   19.231962] IPv6: ADDRCONF(NETDEV_CHANGE): wlan0: link becomes ready
[  135.366866] Bridge firewalling registered
[  135.882893] nvidia-modeset: Loading NVIDIA UNIX Open Kernel Mode Setting Driver for aarch64  35.4.1  Release Build  (buildbrain@mobile-u64-6422-d7000)  Tue Aug  1 12:45:42 PDT 2023
[  136.136083] NVRM rpcRmApiControl_dce: NVRM_RPC_DCE: Failed RM ctrl call cmd:0x731341 result 0xffff:
[  136.154864] cpufreq: cpu4,cur:2140000,set:1984000,set ndiv:155
[  734.502407] usb 1-2.3: USB disconnect, device number 4
[  734.502420] usb 1-2.3.1: USB disconnect, device number 5
[  734.503438] usb 1-2.3.3: USB disconnect, device number 6
[ 3395.900354] can: controller area network core
[ 3395.900420] NET: Registered protocol family 29
[ 3395.909828] can: raw protocol
[ 3395.920275] CAN device driver interface
[ 3395.927727]   Message RAM Configuration
                | base addr   |0x0c312000|
                | sidfc_flssa |0x00000000|
                | xidfc_flesa |0x00000040|
                | rxf0c_f0sa  |0x000000c0|
                | rxf1c_f1sa  |0x000009c0|
                | rxbc_rbsa   |0x000009c0|
                | txefc_efsa  |0x000009c0|
                | txbc_tbsa   |0x00000a40|
                | tmc_tmsa    |0x00000ec0|
                | mram size   |0x00001000|
[ 3395.929055] Release 3.2.3 from 09.06.2018
[ 3395.929485] net can0: mttcan device registered (regs=00000000fd2c00a9, irq=110)
[ 3395.936534] mttcan c310000.mttcan can0: Bitrate set
[ 3395.936667] mttcan_controller_config: ctrlmode 30
[ 3395.936688] mttcan c310000.mttcan can0: Bitrate set
[ 3395.936796] IPv6: ADDRCONF(NETDEV_CHANGE): can0: link becomes ready

This is my canfd test code.
canfd_.zip (2.1 KB)

[KevinFFF]

CAN transceiver is necessary for CAN communication.

Please refer to Jetson/L4T/peripheral/ - eLinux.org for how we verify CAN.