AM2634: CAN-FD Rx FIFO always crashes on second frame (null pointer in rxMapping[])

Hi Justin,

Thanks for reaching out and providing a detailed description of your current test results.

I am looking into this issue and will provide a response before the end of the week. Thank you for your patience.

Best Regards,

Zackary Fleenor

Great thank you. Please let me know if I can provide additional context. This is quite urgent for our needs.

Hi Zackary, thanks for getting back to me.

1) I've stepped through the function, running the `canfd_external_read_write_am263x-cc_r5fss0-0_nortos_ti-arm-clang` imported example unchanged. Looks like even the first call to `SetupI2CTransfer` from `mcanEnableTransceiver` is causing the failure, receiving the error `Cortex_R5_0: ASSERT: 0.181s: ../canfd_transceiver.c:SetupI2CTransfer:103: SystemP_SUCCESS == status failed !!!` on the terminal.

https://github.com/TexasInstruments/mcupsdk-core/blob/next/examples/drivers/mcan/canfd_external_read_write/am263x-cc/canfd_transceiver.c#L71

2) Initially I have not modified the example from its original state (besides commenting out mcanEnableTransceiver). So the syscfg can be found here

https://github.com/TexasInstruments/mcupsdk-core/blob/next/examples/drivers/mcan/canfd_external_read_write/am263x-cc/r5fss0-0_nortos/example.syscfg

However, when I try to change the syscfg with the following, it still halts and fails when the interrupt status `MCAN_INTR_SRC_RX_FIFO0_NEW_MSG` is found (instead of the `MCAN_INTR_SRC_DEDICATED_RX_BUFF_MSG` for a buffer interrupt).

That being said, I can configure this example program to successfully send TX messages from whatever CAN ID, and still receive RX messages with CAN ID 0x0, just not accepting any RX with a different CAN ID.

From modifying the `canfd_external_read_write_am263x-cc_r5fss0-0_nortos_ti-arm-clang` imported example, here is my configuration in syscfg when I try to disable the filter and enable the rx fifo. This has the same failure in which it will receive one message in the RX FIFO, and hard fault the program upon the second received message in the RX FIFO (due to the null pointer deref).

mcan1.$name = "CONFIG_MCAN0";
mcan1.sdkInfra = "HLD";
mcan1.transferMode = "CALLBACK";
mcan1.transferCallbackFxn = "App_CANFDTransferCallback";
mcan1.errorCallbackFxn = "App_CANFDErrorCallback";
mcan1.darEnable = true;
mcan1.autoWkupEnable = true;
mcan1.wkupReqEnable = true;
mcan1.additionalCoreConfig = true;
mcan1.enableLoopback = false;
mcan1.loopbackMode = "EXTERNAL";
mcan1.nomPseg1 = 8;
mcan1.nomPseg2 = 2;
mcan1.tdcEnable = true;
mcan1.rxMemType = "FIFO";
mcan1.extendedFilterEleConfig = "MCAN_EXT_FILT_ELEM_DISABLE";
mcan1.standardFilterEleConfig = "MCAN_STD_FILT_ELEM_DISABLE";
mcan1.MCAN.$assign = "MCAN1";

And here is a modified `canfd_external_read_write_main`

#include <string.h>
#include <kernel/dpl/SemaphoreP.h>
#include <kernel/dpl/ClockP.h>
#include "ti_drivers_config.h"
#include "ti_drivers_open_close.h"
#include "ti_board_open_close.h"

/** \brief Maximum data size for CAN FD frames */
#define MCAN_APP_MAX_DATA_SIZE 64U

CANFD_MessageObject rxMsgObject;
static SemaphoreP_Object gMcanRxDoneSem;
uint8_t rxData[MCAN_APP_MAX_DATA_SIZE] = {0};
volatile uint32_t totalMessagesReceived = 0U;

void mcanEnableTransceiver(void);

void canfd_external_read_write_main(void *args)
{
CANFD_MsgObjHandle rxMsgObjHandle;
int32_t status = SystemP_SUCCESS;

/* Open drivers to open the UART driver for console */
Drivers_open();
Board_driversOpen();

// mcanEnableTransceiver();

status = SemaphoreP_constructBinary(&gMcanRxDoneSem, 0);
DebugP_assert(SystemP_SUCCESS == status);

DebugP_log("\r\n[MCAN] CAN RX FIFO Monitor Started...\r\n");
DebugP_log("Waiting for CAN messages (press CTRL+C to stop)...\r\n\r\n");

/* Setup the receive message object for FIFO operation */
rxMsgObject.direction = CANFD_Direction_RX;
rxMsgObject.msgIdType = CANFD_MCANXidType_29_BIT; /* Accept both 11-bit and 29-bit IDs */
rxMsgObject.startMsgId = 0x0; /* Start ID (not used for FIFO) */
rxMsgObject.endMsgId = 0x1FFFFFFF; /* End ID (accept all) */
rxMsgObject.args = (uint8_t *)rxData;
rxMsgObject.dataLength = MCAN_APP_MAX_DATA_SIZE;
status = CANFD_createMsgObject(gCanfdHandle[CONFIG_MCAN0], &rxMsgObject);
if (status != SystemP_SUCCESS)
{
DebugP_log("Error: CANFD create Rx message object failed\r\n");
return;
}
rxMsgObjHandle = &rxMsgObject;

/* Main reception loop */
while (1)
{
/* Read from FIFO (non-blocking) */
status = CANFD_read(rxMsgObjHandle, 1, &rxData[0]);
if (status == SystemP_SUCCESS)
{
/* Wait for RX completion */
SemaphoreP_pend(&gMcanRxDoneSem, SystemP_WAIT_FOREVER);

totalMessagesReceived++;

/* Print first 8 bytes of data */
DebugP_log("MSG #%u: Data: ", totalMessagesReceived);
uint32_t bytesToPrint = (rxMsgObject.dataLength > 8) ? 8 : rxMsgObject.dataLength;
for (uint32_t i = 0; i < bytesToPrint; i++)
{
DebugP_log("%02X ", rxData[i]);
}
if (rxMsgObject.dataLength > 8)
{
DebugP_log("... (+%u more)", rxMsgObject.dataLength - 8);
}
DebugP_log("\r\n");
}
else
{
/* Small delay to prevent busy waiting */
ClockP_usleep(1000); /* 1ms delay */
}
}

/* Cleanup (this code will never be reached in the infinite loop) */
SemaphoreP_destruct(&gMcanRxDoneSem);
status = CANFD_deleteMsgObject(rxMsgObjHandle);

Board_driversClose();
Drivers_close();

return;
}

void App_CANFDTransferCallback(void *args, CANFD_Reason reason)
{
if (reason == CANFD_Reason_RX)
{
SemaphoreP_post((SemaphoreP_Object *)&gMcanRxDoneSem);
}
}

void App_CANFDErrorCallback(void *args, CANFD_Reason reason)
{
DebugP_log("CAN Error: Reason code 0x%x\r\n", reason);
}

Please let me know if I should be doing anything differently.

Is there an example that will run on the AM2634 dev board that has CAN FD rx FIFO enabled I can use as a reference? This would be the most helpful. 

Hey Justin,

I am assigning this thread to our SW expert to provide additional guidance and possible timeline for CAN-FD RX FIFO example.

Please allow some time for review and additional feedback.

Best Regards,

Zackary Fleenor

Great thanks Zackary. Just bumping this thread.

Hey Justin,

I have received this thread, please give me some time, probably until mid of next week to replicate it on my end and check further. It will be helpful if you could attach your modified project as a zip file here.

Meantime you can refer to this example "mcan_loopback_polling" that demonstrates Tx and Rx used in FIFO mode, although it is an HLD example and not LLD one like the canfd example you're referring to. So in this case the configurations will be found within the source code itself, instead of in sysconfig.

Best Regards,
Aswathi 

Hi Aswathi,

Here is a zipped file of my modified code. I attempted to view the mcan_loopback_polling example but could not correlate it to using fdcan FIFO mode. Again, every time the board receives not a message with CAN ID 0x0, the fifo pointer is nullified and the second message causes a hard crash.

Is there anything you have been able to test for this? A working FIFO with CAN FD example, that would be able to send messages on any can id and receive messages on any can id would be ideal.

Thank you.

canfd_external_read_write_am263x-cc_r5fss0-0_nortos_ti-arm-clang.zip

Hi Justin,

Thanks for sharing the program. 

1. Paste the below file in this path: {SDK}/source/drivers/mcan/v0/

canfd.c

2. Import this project to CCS

2604.canfd_external_read_write_am263x-cc_r5fss0-0_nortos_ti-arm-clang.zip

It should fix the transceiver issue and the crashing issue. But both Tx and Rx is in Buffer mode. I do not have the hardware to test for FIFO mode currently. Let me know if FIFO selection via sysconfig is still not working with this updated project. I will try it on my end on Tuesday. 

Best Regards,
Aswathi

Hi Aswathi, I'm having trouble running your package with MCU_PLUS_SDK_AMXXX v7.3.0.01. Could you please provide me with details about what should be changed in my syscfg and the main function as provided in my previous zip file.

There also seems to be a massive diff between the `canfd.c` you send and the one I have in mcu_plus_sdk_am263x_10_01_00_31.

Can this not be supported on a more recent version of the sdk like v10.01.00.31 I am using?

Thanks for looking into the fifo option, this is ultimately what we need working.

Hi Aswathi, any update here? Thanks

Hi Justin,
Apologies for the delay, I am not keeping well. I will get someone in the team to help you with the migration of the files I sent. Thanks for your patience.

Thanks,
Aswathi