STM32H723 enable icache and dcache disable mpu: hardfault occurs with one piece among 100.

[zxc]

When we were working on a small batch, we encountered a situation where one of about 100 pcbs would frequently trigger a hardfault. We found that the problem would recur when the cache was enabled. When the mpu was enabled and configured correctly, it would run normally. Only this one MCU had this problem. We determined that this was an individual, low-probability problem. Through experiments, we felt that the default memory attribute of its peripherals was normal, not device, which caused the error when accessing a reserved address during cache.

[Ozone]

Software, as a sequence of instructions, is consistent, and does behave the same every time.

I suspect you have a problem with your power supply, the core clock frequency is at the limit, or both.
Or your PCB has EMI issues.

[zxc]

If it is a hardware problem, after I reconfigure the MPU, it will return to normal. The default MPU or not turning on the MPU (this is the default) will not work properly and the gpio initialization will hang.

[mƎALLEm]

Hello,

1- 100 boards are the same?

2- Same application?

3- What do you mean by configuring the MPU? give more details about that config.

4- Did you enable the MPU background config preventing the speculative access?:

void MPU_Config(void)
{
  MPU_Region_InitTypeDef MPU_InitStruct;

  /* Disable the MPU */
  HAL_MPU_Disable();

  /* Configure the MPU as Strongly ordered for not defined regions */
  MPU_InitStruct.Enable = MPU_REGION_ENABLE;
  MPU_InitStruct.BaseAddress = 0x00;
  MPU_InitStruct.Size = MPU_REGION_SIZE_4GB;
  MPU_InitStruct.AccessPermission = MPU_REGION_NO_ACCESS;
  MPU_InitStruct.IsBufferable = MPU_ACCESS_NOT_BUFFERABLE;
  MPU_InitStruct.IsCacheable = MPU_ACCESS_NOT_CACHEABLE;
  MPU_InitStruct.IsShareable = MPU_ACCESS_SHAREABLE;
  MPU_InitStruct.Number = MPU_REGION_NUMBER0;
  MPU_InitStruct.TypeExtField = MPU_TEX_LEVEL0;
  MPU_InitStruct.SubRegionDisable = 0x87;
  MPU_InitStruct.DisableExec = MPU_INSTRUCTION_ACCESS_DISABLE;

  HAL_MPU_ConfigRegion(&MPU_InitStruct);

  /* Enable the MPU */
  HAL_MPU_Enable(MPU_PRIVILEGED_DEFAULT);
}

[zxc]

1-> yes, all the same, 2->yes,all the same, 

3 use mpu_config or not config mpu, enable icache or dcache will hardfault when call mx_gpio_init()

int main(void)
{

/* USER CODE BEGIN 1 */

/* USER CODE END 1 */

/* MPU Configuration--------------------------------------------------------*/
MPU_Config();

/* Enable the CPU Cache */

/* Enable I-Cache---------------------------------------------------------*/
SCB_EnableICache();

/* Enable D-Cache---------------------------------------------------------*/
SCB_EnableDCache();

/* MCU Configuration--------------------------------------------------------*/

/* Reset of all peripherals, Initializes the Flash interface and the Systick. */
HAL_Init();

/* USER CODE BEGIN Init */

/* USER CODE END Init */

/* Configure the system clock */
SystemClock_Config();

/* Configure the peripherals common clocks */
PeriphCommonClock_Config();

/* USER CODE BEGIN SysInit */
//
// SCB_InvalidateICache();
// SCB_InvalidateDCache();
// __DSB();
// __ISB();
/* USER CODE END SysInit */

/* Initialize all configured peripherals */
MX_GPIO_Init();
MX_DMA_Init();
MX_USART1_UART_Init();
MX_RAMECC_Init();
/* USER CODE BEGIN 2 */

printf("\033[2J\033[H");
//uart5_testcase0();
//imu_testcase1();
/* USER CODE END 2 */

/* Init scheduler */
osKernelInitialize(); /* Call init function for freertos objects (in cmsis_os2.c) */
MX_FREERTOS_Init();

/* Start scheduler */
osKernelStart();

/* We should never get here as control is now taken by the scheduler */

/* Infinite loop */
/* USER CODE BEGIN WHILE */
while (1)
{
/* USER CODE END WHILE */

/* USER CODE BEGIN 3 */
}
/* USER CODE END 3 */
}

void MPU_Config(void)
{
  MPU_Region_InitTypeDef MPU_InitStruct = {0};

  /* Disables the MPU */
  HAL_MPU_Disable();

  /** Initializes and configures the Region and the memory to be protected
  */
  MPU_InitStruct.Enable = MPU_REGION_ENABLE;
  MPU_InitStruct.Number = MPU_REGION_NUMBER0;
  MPU_InitStruct.BaseAddress = 0x0;
  MPU_InitStruct.Size = MPU_REGION_SIZE_4GB;
  MPU_InitStruct.SubRegionDisable = 0x87;
  MPU_InitStruct.TypeExtField = MPU_TEX_LEVEL0;
  MPU_InitStruct.AccessPermission = MPU_REGION_NO_ACCESS;
  MPU_InitStruct.DisableExec = MPU_INSTRUCTION_ACCESS_DISABLE;
  MPU_InitStruct.IsShareable = MPU_ACCESS_SHAREABLE;
  MPU_InitStruct.IsCacheable = MPU_ACCESS_NOT_CACHEABLE;
  MPU_InitStruct.IsBufferable = MPU_ACCESS_NOT_BUFFERABLE;

  HAL_MPU_ConfigRegion(&MPU_InitStruct);
  /* Enables the MPU */
  HAL_MPU_Enable(MPU_PRIVILEGED_DEFAULT);

}

[zxc]

mpu config like this,it will work ok

void MPU_Config(void)
{
  MPU_Region_InitTypeDef MPU_InitStruct = {0};

  /* Disables the MPU */
  HAL_MPU_Disable();

  /** Initializes and configures the Region and the memory to be protected
  */
  MPU_InitStruct.Enable = MPU_REGION_ENABLE;
  MPU_InitStruct.Number = MPU_REGION_NUMBER0;
  MPU_InitStruct.BaseAddress = 0x0;
  MPU_InitStruct.Size = MPU_REGION_SIZE_4GB;
  MPU_InitStruct.SubRegionDisable = 0x00;
  MPU_InitStruct.TypeExtField = MPU_TEX_LEVEL1;
  MPU_InitStruct.AccessPermission = MPU_REGION_FULL_ACCESS;
  MPU_InitStruct.DisableExec = MPU_INSTRUCTION_ACCESS_ENABLE;
  MPU_InitStruct.IsShareable = MPU_ACCESS_NOT_SHAREABLE;
  MPU_InitStruct.IsCacheable = MPU_ACCESS_CACHEABLE;
  MPU_InitStruct.IsBufferable = MPU_ACCESS_NOT_BUFFERABLE;

  HAL_MPU_ConfigRegion(&MPU_InitStruct);

  /** Initializes and configures the Region and the memory to be protected
  */
  MPU_InitStruct.Number = MPU_REGION_NUMBER1;
  MPU_InitStruct.BaseAddress = 0x40000000;
  MPU_InitStruct.Size = MPU_REGION_SIZE_512MB;
  MPU_InitStruct.SubRegionDisable = 0x0;
  MPU_InitStruct.TypeExtField = MPU_TEX_LEVEL0;
  MPU_InitStruct.DisableExec = MPU_INSTRUCTION_ACCESS_DISABLE;
  MPU_InitStruct.IsShareable = MPU_ACCESS_SHAREABLE;
  MPU_InitStruct.IsCacheable = MPU_ACCESS_NOT_CACHEABLE;

  HAL_MPU_ConfigRegion(&MPU_InitStruct);
  /* Enables the MPU */
  HAL_MPU_Enable(MPU_HFNMI_PRIVDEF_NONE);

}

[mƎALLEm]

Hello,

As it's showing an issue in one piece among 100 boards, I don't think we can help you efficiently as it could be a quality issue or could be an issue in the PCB or the soldering. So, I invite you to contact your local FAE, or open a request over this online support link.

[zxc]

I think this problem is a yield rate problem, and it seems to be very serious. I encountered the same problem in another batch of 5 samples.

[Pavel A.]

When you set up the MPU and enable it as in your latter MPU_Config() snippet - do all the boards "work well" ?

> 3 use mpu_config or not config mpu, enable icache or dcache will hardfault when call mx_gpio_init()

Of course this will fault. Your code runs in the range of 0x08000000 - which you've just disabled with MPU_REGION_NO_ACCESS. (I don't understand how the program gets to mx_gpio_init ).

Power glitches or too small number of flash wait states can cause errors in fetching instructions, and caching can mask or delay these errors.

[zxc]

Edited by ST moderator to follow the community rules especially for the code sharing. So in next time, please use </> button to paste a code.

mpu config same as C:\Users\xxxx\STM32Cube\Repository\STM32Cube_FW_H7_V1.12.1\Projects\NUCLEO-H723ZG\Examples\DMA\DMAMUX_RequestGen\MDK-ARM,

static void MPU_Config(void)
{
MPU_Region_InitTypeDef MPU_InitStruct;

/* Disable the MPU */
HAL_MPU_Disable();

/* Configure the MPU as Strongly ordered for not defined regions */
MPU_InitStruct.Enable = MPU_REGION_ENABLE;
MPU_InitStruct.BaseAddress = 0x00;
MPU_InitStruct.Size = MPU_REGION_SIZE_4GB;
MPU_InitStruct.AccessPermission = MPU_REGION_NO_ACCESS;
MPU_InitStruct.IsBufferable = MPU_ACCESS_NOT_BUFFERABLE;
MPU_InitStruct.IsCacheable = MPU_ACCESS_NOT_CACHEABLE;
MPU_InitStruct.IsShareable = MPU_ACCESS_SHAREABLE;
MPU_InitStruct.Number = MPU_REGION_NUMBER0;
MPU_InitStruct.TypeExtField = MPU_TEX_LEVEL0;
MPU_InitStruct.SubRegionDisable = 0x87;
MPU_InitStruct.DisableExec = MPU_INSTRUCTION_ACCESS_DISABLE;

HAL_MPU_ConfigRegion(&MPU_InitStruct);

/* Enable the MPU */
HAL_MPU_Enable(MPU_PRIVILEGED_DEFAULT);
}

I have found that several pcba are prone to abnormalities on dcache, but the performance is not exactly the same. One of them does not abnormally when the mpu is not configured by default, but only when dcache and icache are enabled. The other one will abnormally when dcahce and icache are enabled, regardless of whether the mpu is configured or not (according to the example method).

But most boards run the same code without any problems.