topic Re: FreeRTOS Message Buffer Core to Core Bus-Fault Error in i.MX RT Crossover MCUs

FreeRTOS Message Buffer Core to Core Bus-Fault Error

Flo1989 — Fri, 30 Jun 2023 09:40:28 GMT

Hello,

we are using the freertos_message_buffer from the example provided in the sdk on a imxrt1176 device.

We extended the memory to send and receive blocks with a length of 1024bytes. So our config looks like this:

#define APP_TASK_STACK_SIZE (configMINIMAL_STACK_SIZE + 100) #define APP_READY_EVENT_DATA (1U) #define APP_MESSAGE_BUFFER_EVENT_DATA (1U) #define APP_MAX_MESSAGE_LENGTH (0x400U) #define APP_MESSAGE_BUFFER_SIZE (0x800U) #define APP_SH_MEM_PRIMARY_TO_SECONDARY_MB_OFFSET (0x0u) #define APP_SH_MEM_SECONDARY_TO_PRIMARY_MB_OFFSET (0x4u) #define APP_SH_MEM_PRIMARY_TO_SECONDARY_MB_STRUCT_OFFSET (0x50u) #define APP_SH_MEM_SECONDARY_TO_PRIMARY_MB_STRUCT_OFFSET (0xA0u) #define APP_SH_MEM_PRIMARY_TO_SECONDARY_BUF_STORAGE_OFFSET (0x100u) #define APP_SH_MEM_SECONDARY_TO_PRIMARY_BUF_STORAGE_OFFSET (0x900u) #define SH_MEM_TOTAL_SIZE (6144U)

It seems the cm7 core tries to notify a task on the cm4 core wich results in a bus-fault error. Normaly the cm7 core should not notify the task, becaouse in the xStreamBuffer struct the xTaskWaitingToSend pointer is NULL.

But if the sbRECEIVE_COMPLETE macro is called the xTaskGenericNotify() fuction is called with the task address from the cm4 task. This results in a BusFault Address Register (BFAR) valid flag.

The rpmsh_sh_mem is located at address 0x202c0000 and looks like this. Here i can see the address of the slave task (0x1FFF6394) which is wrong called from the cm7 in the xSecondaryToPrimaryMessageBufferStruct at address 0x202C0060.

From the call hirarchy the sbRECEIVE_COMPLETE Macro should not call xTaskNotify because the xStreamBuffers xTaskWaitingToReceive is NULL.

Has anyone an idea what is happening here?

Thank you,

Florian

Re: FreeRTOS Message Buffer Core to Core Bus-Fault Error

jingpan — Tue, 04 Jul 2023 10:04:00 GMT

Hi @Flo1989 ,

I modified freertos_message_buffers_cm7 and freertos_message_buffers_cm4 project using your code. But I don't see any problem. What else do you modified?

Regards,

Jing

Re: FreeRTOS Message Buffer Core to Core Bus-Fault Error

Flo1989 — Thu, 06 Jul 2023 06:27:20 GMT

Hi Jing,

we are using the message buffers in a bigger software that i can not share with you. The problem occures not immediately. The sofware is running for 10h with much traffic through the message buffer.

I now overwrote the sbRECEIVE_COMPLETE like the sbSEND_COMPLETED macro is overwritten. But i do nothing in the sbRECEIVE_COMPLETED macro function now. With this change the software is running well. But i would like to understand whats the reason for this behaviour.

Thanks,

Florian

Re: FreeRTOS Message Buffer Core to Core Bus-Fault Error

jingpan — Fri, 07 Jul 2023 03:39:10 GMT

Hi @Flo1989 ,

Sometimes busfault will not happened immediately after the wrong instruction.

Regards,

Jing