esp-idf/components/freertos/test/test_suspend_scheduler.c

/* Tests for FreeRTOS scheduler suspend & resume all tasks */
#include <stdio.h>

#include "freertos/FreeRTOS.h"
#include "freertos/task.h"
#include "freertos/semphr.h"
#include "freertos/queue.h"
#include "freertos/xtensa_api.h"
#include "unity.h"
#include "soc/cpu.h"

#include "driver/timer.h"

static SemaphoreHandle_t isr_semaphore;
static volatile unsigned isr_count;

/* Timer ISR increments an ISR counter, and signals a
   mutex semaphore to wake up another counter task */
static void timer_group0_isr(void *vp_arg)
{
    TIMERG0.int_clr_timers.t0 = 1;
    TIMERG0.hw_timer[TIMER_0].update = 1;
    TIMERG0.hw_timer[TIMER_0].config.alarm_en = 1;
    portBASE_TYPE higher_awoken = pdFALSE;
    isr_count++;
    xSemaphoreGiveFromISR(isr_semaphore, &higher_awoken);
    if (higher_awoken == pdTRUE) {
        portYIELD_FROM_ISR();
    }
}

typedef struct {
    SemaphoreHandle_t trigger_sem;
    volatile unsigned counter;
} counter_config_t;

static void counter_task_fn(void *vp_config)
{
    counter_config_t *config = (counter_config_t *)vp_config;
    printf("counter_task running...\n");
    while(1) {
        xSemaphoreTake(config->trigger_sem, portMAX_DELAY);
        config->counter++;
    }
}


/* This test verifies that an interrupt can wake up a task while the scheduler is disabled.

   In the FreeRTOS implementation, this exercises the xPendingReadyList for that core.
 */
TEST_CASE("Handle pending context switch while scheduler disabled", "[freertos]")
{
    isr_count = 0;
    isr_semaphore = xSemaphoreCreateMutex();
    TaskHandle_t counter_task;
    intr_handle_t isr_handle = NULL;

    counter_config_t count_config = {
        .trigger_sem = isr_semaphore,
        .counter = 0,
    };
    xTaskCreatePinnedToCore(counter_task_fn, "counter", 2048,
                            &count_config, UNITY_FREERTOS_PRIORITY + 1,
                            &counter_task, UNITY_FREERTOS_CPU);

    /* Configure timer ISR */
    const timer_config_t timer_config = {
        .alarm_en = 1,
        .auto_reload = 1,
        .counter_dir = TIMER_COUNT_UP,
        .divider = 1,
        .intr_type = TIMER_INTR_LEVEL,
        .counter_en = TIMER_PAUSE,
    };
    /* Configure timer */
    timer_init(TIMER_GROUP_0, TIMER_0, &timer_config);
    timer_pause(TIMER_GROUP_0, TIMER_0);
    timer_set_counter_value(TIMER_GROUP_0, TIMER_0, 0);
    timer_set_alarm_value(TIMER_GROUP_0, TIMER_0, 1000);
    timer_enable_intr(TIMER_GROUP_0, TIMER_0);
    timer_isr_register(TIMER_GROUP_0, TIMER_0, timer_group0_isr, NULL, 0, &isr_handle);
    timer_start(TIMER_GROUP_0, TIMER_0);

    vTaskDelay(5);

    // Check some counts have been triggered via the ISR
    TEST_ASSERT(count_config.counter > 10);
    TEST_ASSERT(isr_count > 10);

    for (int i = 0; i < 20; i++) {
        vTaskSuspendAll();
        esp_intr_noniram_disable();

        unsigned no_sched_task = count_config.counter;

        // scheduler off on this CPU...
        ets_delay_us(20 * 1000);

        //TEST_ASSERT_NOT_EQUAL(no_sched_isr, isr_count);
        TEST_ASSERT_EQUAL(count_config.counter, no_sched_task);

        // disable timer interrupts
        timer_disable_intr(TIMER_GROUP_0, TIMER_0);

        // When we resume scheduler, we expect the counter task
        // will preempt and count at least one more item
        esp_intr_noniram_enable();
        xTaskResumeAll();

        TEST_ASSERT_NOT_EQUAL(count_config.counter, no_sched_task);
    }

    esp_intr_free(isr_handle);
    timer_disable_intr(TIMER_GROUP_0, TIMER_0);

    vTaskDelete(counter_task);
    vSemaphoreDelete(isr_semaphore);
}

/* Multiple tasks on different cores can be added to the pending ready list
   while scheduler is suspended, and should be started once the scheduler
   resumes.
*/
TEST_CASE("Handle waking multiple tasks while scheduler suspended", "[freertos]")
{
    #define TASKS_PER_PROC 4
    TaskHandle_t tasks[portNUM_PROCESSORS][TASKS_PER_PROC] = { 0 };
    counter_config_t counters[portNUM_PROCESSORS][TASKS_PER_PROC] = { 0 };

    /* Start all the tasks, they will block on isr_semaphore */
    for (int p = 0; p < portNUM_PROCESSORS; p++) {
        for (int t = 0; t < TASKS_PER_PROC; t++) {
            counters[p][t].trigger_sem = xSemaphoreCreateMutex();
            TEST_ASSERT_NOT_NULL( counters[p][t].trigger_sem );
            TEST_ASSERT( xSemaphoreTake(counters[p][t].trigger_sem, 0) );
            xTaskCreatePinnedToCore(counter_task_fn, "counter", 2048,
                                    &counters[p][t], UNITY_FREERTOS_PRIORITY + 1,
                                    &tasks[p][t], p);
            TEST_ASSERT_NOT_NULL( tasks[p][t] );
        }
    }

    /* takes a while to initialize tasks on both cores, sometimes... */
    vTaskDelay(TASKS_PER_PROC * portNUM_PROCESSORS * 3);

    /* Check nothing is counting, each counter should be blocked on its trigger_sem */
    for (int p = 0; p < portNUM_PROCESSORS; p++) {
        for (int t = 0; t < TASKS_PER_PROC; t++) {
            TEST_ASSERT_EQUAL(0, counters[p][t].counter);
        }
    }

    /* Suspend scheduler on this CPU */
    vTaskSuspendAll();

    /* Give all the semaphores once. You might expect this will wake up tasks on the other
       CPU (where the scheduler is not suspended) but it doesn't do this in the current implementation
       - all tasks are added to xPendingReadyList and woken up later. See note in the freertos-smp docs.
     */
    for (int p = 0; p < portNUM_PROCESSORS; p++) {
        for (int t = 0; t < TASKS_PER_PROC; t++) {
            xSemaphoreGive(counters[p][t].trigger_sem);
        }
   }

    ets_delay_us(2 * 1000); /* Can't vTaskDelay() while scheduler is suspended, but let other CPU do some things */

    for (int p = 0; p < portNUM_PROCESSORS; p++) {
        for (int t = 0; t < TASKS_PER_PROC; t++) {
            /* You might expect that this is '1' for the other CPU, but it's not (see comment above) */
            ets_printf("Checking CPU %d task %d (expected 0 actual %d)\n", p, t, counters[p][t].counter);
            TEST_ASSERT_EQUAL(0, counters[p][t].counter);
        }
    }

    /* Resume scheduler */
    xTaskResumeAll();

    vTaskDelay(TASKS_PER_PROC * 2);

    /* Now the tasks on both CPUs should have been woken once and counted once. */
    for (int p = 0; p < portNUM_PROCESSORS; p++) {
        for (int t = 0; t < TASKS_PER_PROC; t++) {
            ets_printf("Checking CPU %d task %d (expected 1 actual %d)\n", p, t, counters[p][t].counter);
            TEST_ASSERT_EQUAL(1, counters[p][t].counter);
        }
    }

    /* Clean up */
    for (int p = 0; p < portNUM_PROCESSORS; p++) {
        for (int t = 0; t < TASKS_PER_PROC; t++) {
            vTaskDelete(tasks[p][t]);
            vSemaphoreDelete(counters[p][t].trigger_sem);
        }
    }
}