CC2674R10: CAN_open() ignores params->userArg

Wolfgang R.

Prodigy 211 points

Part Number: CC2674R10

Tool/software:

Hi all,

using simplelink_cc13xx_cc26xx_sdk_7_40_00_77 CAN driver for TCAN455X via SPI

CAN_open() is passed a CAN_Params struct:

typedef struct
{
    const CAN_MsgRAMConfig *msgRAMConfig;  /*!< Pointer to message RAM configuration */
    const CAN_BitRateTimingRaw *bitTiming; /*!< Pointer to raw bit timing values */
    CAN_EventCbk eventCbk;                 /*!< Pointer to event callback function */
    uint32_t eventMask;                    /*!< Mask of events to call event callback function for */
    void *userArg;                         /*!< User supplied arg for callback */
} CAN_Params;

Observation: the provided 'eventCbk' function get called as configured, but its 'userArg' parameter is always NULL, that is, params->userArg passed to CAN_open() does not get passed on to the callback as expected:

 *  @param[in]  userArg       A user supplied argument specified
 *                            in CAN_Params.
 */
typedef void (*CAN_EventCbk)(CAN_Handle handle, uint32_t event, uint32_t data, void *userArg);

CAN_open() does not transfer member 'userArg' to the CAN_Object - here's the code snippet out of CAN_open() in source/TI/drivers/CAN.c where one would expect his to happen:

'params' is also passed to CAN_initDevice() in source/TI/drivers/can/TCAN455X.c, but struct member 'userArg' is ignored there as well.

Is this a known limitation that will be fixed soon? I wanted to use 'userArg' and now have to resort to a global variable to work around this.

Regards,

Wolfgang

2 months ago

0 Toby P 2 months ago

TI__Mastermind 31110 points

Hi Wolfgang,

I see what you're saying. To me also it seems the CAN_Params.userArg is not actually referenced.

A workaround could be:

    /* Open CAN driver with default configuration */
    CAN_Params_init(&canParams);
    canParams.eventCbk  = eventCallback;
    canParams.eventMask = CAN_EVENT_MASK;
    canParams.userArg   = (void *) yourArg; // toby added

    canHandle = CAN_open(CONFIG_CAN_0, &canParams);
    if (canHandle == NULL)
    {
        /* CAN_open() failed */
        while (1) {}
    }

    // toby added
    canHandle->object->userArg = canParams.userArg;
    // end added

I'll check with the driver team if this is a known issue, though I suspect it should be.

Thanks,
Toby

0 Toby P 2 months ago in reply to Toby P

TI__Mastermind 31110 points

A ticket is now filed to address this issue.

Thanks for reporting it!

I cannot provide an exact timeline for it, but my initial estimate would be end of Q3 or Q4.

0 Wolfgang R. 2 months ago in reply to Toby P

Prodigy 211 points

Hi Toby,

I also came up with this workaround, but it should be noted that it bears the (very small) risk of still getting userArg==NULL in early callbacks during initialization, depending on event mask and bus traffic. So userArg should be checked in the callback and not blindly dereferenced (good practice anyway).

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CC2674R10: CAN_open() ignores params->userArg