Problem on pl to ps interrupt with freertos on vitis ide 2024.2

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Hi everyone,

I’m working with Zynq7020 (ZC702 Board). I created a Vivado project where i generate interrupts from PL to PS. The following image shows that two debounced pushbuttons are connected to the line IRQ_F2P of Zynq7 Processing System.

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I generated the bitstream, and created the platform in VITIS IDE 2024.2

Firstly I worked with a BAREMETAL platform, where I demonstrated that interrupts work. (So I figured out that the problem is not hardware!). The two interrupts line have the ID 61 and 62 respectively.

Then I generated a FREERTOS platform, but Interrupt doesn’t work anymore!

This is my code (to simplify, I’m only using interrupt from just one pushbutton).

/* ============================================================
 *  main.c  —  FreeRTOS + AXI GPIO interrupt  —  ZC702
 * ============================================================ */
 
#include "FreeRTOS.h"
#include "task.h"
#include "xgpio.h"
#include "xil_printf.h"
#include "xparameters.h"
#include "portmacro.h"
#include "xstatus.h"
#include "xil_exception.h"
#include "xil_types.h"
 
#define LED_BASE_ADDR   XPAR_LED_19_BASEADDR
#define BTN1_BASE_ADDR  XPAR_BUTTON_1_BASEADDR
#define BTN_1_INT_ID    XPS_FPGA0_INT_ID  //61
#define BTN_INT_MASK    XGPIO_IR_CH1_MASK
#define GPIO_CHANNEL    1
 
XGpio LED_Inst;
XGpio BTN1_Inst;
 
static TaskHandle_t TaskLed  = NULL;
static TaskHandle_t TaskHand = NULL;
static TaskHandle_t xHandle  = NULL;
 
static void Task_Led  (void *pvParameters);
static void Task_HAND (void *pvParameters);
static void BTN1_ISR  (void *CallBackRef);
static void BTN1_Init (void);
 
 
 
//pushbutton 1 ISR
static void BTN1_ISR(void *CallBackRef)
{
    BaseType_t xHigherPriorityTaskWoken = pdFALSE;
    XGpio *GpioPtr = (XGpio *)CallBackRef;
 
    XGpio_InterruptClear(GpioPtr, BTN_INT_MASK);
 
    if (xHandle != NULL)
        vTaskNotifyGiveFromISR(xHandle, &xHigherPriorityTaskWoken);
 
    portYIELD_FROM_ISR(xHigherPriorityTaskWoken);
}
 
 
 
 //pushbutton 1 initializiation
 
static void BTN1_Init(void)
{
    XGpio_SetDataDirection(&BTN1_Inst, GPIO_CHANNEL, 0xFF);
    XGpio_InterruptEnable(&BTN1_Inst, BTN_INT_MASK);
    XGpio_InterruptGlobalEnable(&BTN1_Inst);
 
    xPortInstallInterruptHandler(BTN_1_INT_ID,
        (Xil_ExceptionHandler)BTN1_ISR,
        (void *)&BTN1_Inst);
 
    vPortEnableInterrupt(BTN_1_INT_ID);
}
 
 
 
int main(void)
{
    int status;
 
    status = XGpio_Initialize(&LED_Inst, LED_BASE_ADDR);
    if (status != XST_SUCCESS) { xil_printf("LED INIT FAILED\n\r"); return XST_FAILURE; }
    XGpio_SetDataDirection(&LED_Inst, GPIO_CHANNEL, 0x00);
    xil_printf("LED INIT OK\n\r");
 
    status = XGpio_Initialize(&BTN1_Inst, BTN1_BASE_ADDR);
    if (status != XST_SUCCESS) { xil_printf("BTN1 INIT FAILED\n\r"); return XST_FAILURE; }
    xil_printf("BTN1 INIT OK\n\r");
 
    xTaskCreate(Task_Led,  "Led",  configMINIMAL_STACK_SIZE,     NULL, tskIDLE_PRIORITY + 1, &TaskLed);
    xTaskCreate(Task_HAND, "HAND", configMINIMAL_STACK_SIZE * 2, NULL, tskIDLE_PRIORITY + 2, &TaskHand);
 
    vTaskStartScheduler();
    for (;;);
    return 0;
}
 
 
 
 //  TASK LED
 
static void Task_Led(void *pvParameters)
{
    const TickType_t x1second = pdMS_TO_TICKS(1000);
    uint8_t ledState = 0;
    for (;;) {
        ledState = (ledState == 0) ? 0x7F : 0x00;
        XGpio_DiscreteWrite(&LED_Inst, GPIO_CHANNEL, ledState);
        vTaskDelay(x1second);
    }
}
 
 
// TASK HANDLER
 
static void Task_HAND(void *pvParameters)
{
    xHandle = xTaskGetCurrentTaskHandle();
    BTN1_Init();
    xil_printf("Ready!, push BTN1\n\r");
    for (;;) {
        ulTaskNotifyTake(pdTRUE, portMAX_DELAY);
        xil_printf("BTN1 pushed!\n\r");
    }
}

VITIS 2024.2 IDE has the following parameters:

XPAR_XILTIMER_ENABLED = 1

SDT = 1

Moreover, I made another trying, where I handle an interrupt generated from the TTC 0, (using xPortInstallInterruptHandler) and it works.

But the xPortInstallInterruptHandler doesn’t work with interrupt from PL!!!

PS: before trying this code, I tried to use the function “XScuGic_Connect”, but it doesn’t work witth FREERTOS because the operating system itself initiliases the GIC.

Thank you in advance!

2

This question is very Xilinx specific. Please reach out to Xilinx as well.

Meanwhile, does this help: Zynq 7020 interrupts under FreeRTOS v10.1.1 - #3 by Steve?

3

I can’t really share specific examples but I have notes to myself about just this topic:

//Zynq is finicky about setting up the FPGA interrupts
//Initialization is done before starting the scheduler
//But connection and enable are done after starting the scheduler

Basically, XScuGic_Connect and XScuGic_Enable should be called after the scheduler is started. All the other init code can be done before the scheduler. There might be a cleaner solution but this has worked for me.

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