STM32F4 SPI interrupts stop firing with FreeRTOS - stm32

Question

I'm trying to make an SPI communication between a F410 MCU and a RPi using SPI.
I post below the code that currently works (without FreeRTOS usage):
main.c
volatile int tx_done = 0;
volatile int rx_done = 0;
void HAL_SPI_TxCpltCallback(SPI_HandleTypeDef *hspi)
{
tx_done = 1;
}
void HAL_SPI_RxCpltCallback(SPI_HandleTypeDef *hspi)
{
rx_done = 1;
}
int main(void)
{
HAL_Init();
SystemClock_Config();
MX_GPIO_Init();
MX_SPI5_Init();
MX_USART2_UART_Init();
const uint8_t BUF_SIZE = 16 * sizeof(uint8_t);
uint8_t buf[16];
// For UART debug
uint8_t dbg_buffer[64];
while (1) {
memset(buf, 0, BUF_SIZE);
HAL_StatusTypeDef ret = HAL_SPI_Receive_IT(&hspi5, (uint8_t*)&buf, BUF_SIZE);
while (rx_done == 0) {};
rx_done = 0;
sprintf((char*) dbg_buffer, "%d %d %d %d %d %d %d %d %d %d %d %d %d %d %d %d]\r\n",
buf[0], buf[1], buf[2], buf[3], buf[4], buf[5], buf[6],
buf[7], buf[8], buf[9], buf[10], buf[11], buf[12],
buf[13], buf[14], buf[15]);
HAL_UART_Transmit(&huart2, dbg_buffer, strlen((char const*) dbg_buffer), 50);
HAL_SPI_Transmit_IT(&hspi5, (uint8_t*) &buf, BUF_SIZE);
while (tx_done == 0) {};
tx_done = 0;
}
}
stm32f4xx_it.c
/**
* #brief This function handles TIM1 trigger and commutation interrupts and TIM11 global interrupt.
*/
void TIM1_TRG_COM_TIM11_IRQHandler(void)
{
HAL_TIM_IRQHandler(&htim11);
}
/**
* #brief This function handles SPI5 global interrupt.
*/
void SPI5_IRQHandler(void)
{
HAL_SPI_IRQHandler(&hspi5);
}
spi.c
/* SPI5 init function */
void MX_SPI5_Init(void)
{
hspi5.Instance = SPI5;
hspi5.Init.Mode = SPI_MODE_SLAVE;
hspi5.Init.Direction = SPI_DIRECTION_2LINES;
hspi5.Init.DataSize = SPI_DATASIZE_8BIT;
hspi5.Init.CLKPolarity = SPI_POLARITY_LOW;
hspi5.Init.CLKPhase = SPI_PHASE_1EDGE;
hspi5.Init.NSS = SPI_NSS_HARD_INPUT;
hspi5.Init.FirstBit = SPI_FIRSTBIT_MSB;
hspi5.Init.TIMode = SPI_TIMODE_DISABLE;
hspi5.Init.CRCCalculation = SPI_CRCCALCULATION_DISABLE;
hspi5.Init.CRCPolynomial = 15;
if (HAL_SPI_Init(&hspi5) != HAL_OK)
{
_Error_Handler(__FILE__, __LINE__);
}
}
void HAL_SPI_MspInit(SPI_HandleTypeDef* spiHandle)
{
[...]
HAL_NVIC_SetPriority(SPI5_IRQn, 5, 0);
HAL_NVIC_EnableIRQ(SPI5_IRQn);
}
This working fine with my test code on the other (raspberry pi) side, sending a SPI frame every second, waiting 100ms and reading the answer from the F410.
Now, when I activate FreeRTOS, I move the while(1) loop content to a task, and creates it with
BaseType_t task1 = xTaskCreate(task_1, "task_1", 512, NULL, tskIDLE_PRIORITY, &xHandle);
and osKernelStart(). I also use the TIM11 as Timebase Source (under SYS tab on CubeMX as advised by the software itself)
Then I have the following behavior: If I place breakpoints inside both Tx/Rx SPI interrupt, I found that a couple (3-4 ?) of them are fired, then never again. If I stop my code I see I'm stucked in the
while (rx_done == 0) {};
loop, confirming that I don't get SPI RX interrupts anymore whereas there is still frame coming on the SPI bus.
To dig a little into that theory, I made another test with this in my task:
while(1) {
memset(buf, 0, 16);
HAL_StatusTypeDef ret = HAL_SPI_Receive_IT(&hspi5, (uint8_t*)&buf, 16);
HAL_GPIO_WritePin(GPIOA, GPIO_PIN_5, GPIO_PIN_SET);
// Wait for RX interrupt, task is suspended to give processing time to (incoming) others tasks
vTaskSuspend(NULL);
HAL_GPIO_WritePin(GPIOA, GPIO_PIN_5, GPIO_PIN_RESET);
}
and in my Rx interrupt, I simply call
xTaskResumeFromISR(task1Handle);
With this code, the first packet sent is read correctly by the STM32F4, and task print it on USART2 and suspend itself again. From then, (checked with a breakpoint inside), the Rx interrupt is never called again, so the task resume inside neither, and my code is frozen...
It really looks like there is a messing between FreeRTOS and STM32 HAL SPI/interrupt handling ?
Any help will be gladly accepted !

Answer 1

Do you call NVIC_PriorityGroupConfig( NVIC_PriorityGroup_4 ); as described in the red text on this page: https://www.freertos.org/RTOS-Cortex-M3-M4.html ?
If you are using an STM32 with the STM32 driver library then ensure all the priority bits are assigned to be preempt priority bits by calling NVIC_PriorityGroupConfig( NVIC_PriorityGroup_4 ); before the RTOS is started.