FDCAN in production mode is not working

[TArre.1]

Hi!

I am using a STM32MP157C-DK2 board to communicate via CAN. To do this, I have created a program in STM32CubeIDE and set the FDCAN parameters:

• Classic mode.
• 150KB/s nominal baud rate.
• HSE clock source (24MH)

 

I have been testing in engineering mode and I was able to receive and send CAN messages (I have connected to an IXXAT device).

My problem starts when I try to do it in production mode:

• I cannot send and receive messages

I do not know if I forgot to set a clock or something to enable FDCAN.

Can someone help me please?

Thanks!

[PatrickF]

Hi @TArre.1​ 

Root clocks (i.e. PLLs, mux) and power supplies are managed by uBoot/Linux.

In order to control them properly, the Device Tree should contain resources required by your Cortex-M4 FW. Also, the resource manager should be enabled.

These are usually configured within CubeMx.

See https://wiki.st.com/stm32mpu/wiki/How_to_configure_system_resources

and https://wiki.st.com/stm32mpu/wiki/Resource_manager_for_coprocessing

and https://wiki.st.com/stm32mpu/wiki/How_to_assign_an_internal_peripheral_to_a_runtime_context

Regards.

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[TArre.1]

Hi @PatrickF​ , thank you for your reply!

I have created the device tree in CubeMx. After reading all the wiki pages, i have verified in my program the following parameters (kernel .dts):

m4_fdcan1_pins_mx: m4_fdcan1_mx-0 {

pins {

pinmux = <STM32_PINMUX('A', 11, RSVD)>, /* FDCAN1_RX */

<STM32_PINMUX('A', 12, RSVD)>; /* FDCAN1_TX */

&m4_m_can1{

pinctrl-names = "default";

pinctrl-0 = <&m4_fdcan1_pins_mx>;

status = "okay";

&m4_rproc{

m4_system_resources{

status = "okay";

&m4_m_can1{

pinctrl-names = "default";

pinctrl-0 = <&m4_fdcan1_pins_mx>;

status = "okay";

I think I have all the parameters set correctly. Is there any other step I have to do?

Thanks!

[PatrickF]

Hi,

note that clocks should be defined in TF-A DT (as well as in uBoot and linux kernel DT).

Check if fdcan_k is from right source: cat /sys/kernel/debug/clk/clk_summary

If not, check if DT is what you expect for FDCAN_CK, e.g. https://github.com/STMicroelectronics/arm-trusted-firmware/blob/v2.6-stm32mp/fdts/stm32mp15xx-dkx.dtsi#L254

Check in your DT that you did not have status = "okay" on &m_can1 node.

Check in your M4 code that you skip the right init when in production mode but still have somewhere a code that enable the FDCAN clocks, e.g. __HAL_RCC_FDCAN_CLK_ENABLE().

Check in your M4 code that you still have GPIO mux for FDCAN pins.

Regards

[TArre.1]

hi @PatrickF​ 

In order to change the clocks, do I have to create my own machine?

I have checked the clocks with the command "cat /sys/kernel/debug/clk/clk_summary" and I have seen that the configuration is not the same as the one I have designed in the STM32CubeIDE:

• "cat /sys/kernel/debug/clk/clk_summary" shows the following:

 clock                        enable_cnt prepare_cnt       rate  accuracy  phase

----------------------------------------------------------------------------------------

clk-hse                                 1           1   24000000         0 0 

  ck_hse                               7           7   24000000         0 0 

     ck_hse_rtc                        0           0    1000000         0 0 

     stgen_k                           1           1   24000000         0 0 

     usbphy_k                          1           1   24000000         0 0 

     ck_per                            1           1   24000000         0 0 

        adc12_k                        1           1   24000000         0 0 

     ref4                              1           1   24000000         0 0 

        pll4                           1           1  594000000         0 0 

           pll4_r                      0           0   74250000         0 0 

           pll4_q                      1           1   31263158         0 0 

              ltdc_px                  1           1   31263158         0 0 

              dsi_px                   0           0   31263158         0 0 

              fdcan_k                  0           0   31263158         0 0 

• In my desing the FDCAN clock is connected to HSE as it can be seen above

I'm thinking that maybe the FDCAN clock is not activated when I turn on the board in production mode

Thanks!