freertos tests: Extend preemption test cases to cross-core wakeup

components/freertos/test/test_preemption.c

@@ -14,23 +14,31 @@
 #include "unity.h"
 #include "soc/cpu.h"
 
-
+static volatile bool trigger;
 static volatile bool flag;
 
-static void task_yield(void *param)
+/* Task:
+   - Waits for 'trigger' variable to be set
+   - Reads the cycle count on this CPU
+   - Pushes it into a queue supplied as a param
+   - Busy-waits until the main task terminates it
+*/
+static void task_send_to_queue(void *param)
 {
     QueueHandle_t queue = (QueueHandle_t) param;
     uint32_t ccount;
+
+    while(!trigger) {}
+
     RSR(CCOUNT, ccount);
     flag = true;
     xQueueSendToBack(queue, &ccount, 0);
     /* This is to ensure that higher priority task
        won't wake anyhow, due to this task terminating.
+
+       The task runs until terminated by the main task.
     */
-    for (int i = 0; i < 1000; i++) {
+    while(1) {}
-        ets_delay_us(1000);
-    }
-    vTaskDelete(NULL);
 }
 
 TEST_CASE("Yield from lower priority task, same CPU", "[freertos]")
@@ -38,11 +46,16 @@ TEST_CASE("Yield from lower priority task, same CPU", "[freertos]")
     /* Do this 3 times, mostly for the benchmark value - the first
        run includes a cache miss so uses more cycles than it should. */
     for (int i = 0; i < 3; i++) {
+        TaskHandle_t sender_task;
         QueueHandle_t queue = xQueueCreate(1, sizeof(uint32_t));
         flag = false;
+        trigger = false;
 
         /* "yield" task sits on our CPU, lower priority to us */
-        xTaskCreatePinnedToCore(task_yield, "YIELD", 2048, (void *)queue, UNITY_FREERTOS_PRIORITY - 1, NULL, UNITY_FREERTOS_CPU);
+        xTaskCreatePinnedToCore(task_send_to_queue, "YIELD", 2048, (void *)queue, UNITY_FREERTOS_PRIORITY - 1, &sender_task, UNITY_FREERTOS_CPU);
+
+        vTaskDelay(1); /* make sure everything is set up */
+        trigger = true;
 
         uint32_t yield_ccount, now_ccount, delta;
         TEST_ASSERT( xQueueReceive(queue, &yield_ccount, 100 / portTICK_PERIOD_MS) );
@@ -54,5 +67,42 @@ TEST_CASE("Yield from lower priority task, same CPU", "[freertos]")
         TEST_ASSERT(delta < 10000);
 
         vQueueDelete(queue);
+        vTaskDelete(sender_task);
+    }
+}
+
+
+TEST_CASE("Yield from lower priority task, other CPU", "[freertos]")
+{
+    uint32_t trigger_ccount, yield_ccount, now_ccount, delta;
+
+    /* Do this 3 times, mostly for the benchmark value - the first
+       run includes a cache miss so uses more cycles than it should. */
+    for (int i = 0; i < 3; i++) {
+        TaskHandle_t sender_task;
+        QueueHandle_t queue = xQueueCreate(1, sizeof(uint32_t));
+        trigger = false;
+        flag = false;
+
+        /* "send_to_queue" task sits on the other CPU, lower priority to us */
+        xTaskCreatePinnedToCore(task_send_to_queue, "YIELD", 2048, (void *)queue, UNITY_FREERTOS_PRIORITY - 1,
+                                &sender_task, !UNITY_FREERTOS_CPU);
+
+        vTaskDelay(2); /* make sure everything is set up */
+        trigger = true;
+        RSR(CCOUNT, trigger_ccount);
+
+        // yield_ccount is not useful in this test as it's the other core's CCOUNT
+        // so we use trigger_ccount instead
+        TEST_ASSERT( xQueueReceive(queue, &yield_ccount, 100 / portTICK_PERIOD_MS) );
+        RSR(CCOUNT, now_ccount);
+        TEST_ASSERT( flag );
+
+        delta = now_ccount - trigger_ccount;
+        printf("Yielding from task on other core took %u cycles\n", delta);
+        TEST_ASSERT(delta < 10000);
+
+        vQueueDelete(queue);
+        vTaskDelete(sender_task);
     }
 }