vfs: add example for eventfd

examples/system/eventfd/main/eventfd_example.c

@@ -0,0 +1,168 @@
+/* eventfd example
+
+   This example code is in the Public Domain (or CC0 licensed, at your option.)
+
+   Unless required by applicable law or agreed to in writing, this
+   software is distributed on an "AS IS" BASIS, WITHOUT WARRANTIES OR
+   CONDITIONS OF ANY KIND, either express or implied.
+*/
+
+#include <stdio.h>
+#include <sys/select.h>
+
+#include "driver/timer.h"
+#include "esp_err.h"
+#include "esp_log.h"
+#include "esp_vfs.h"
+#include "esp_vfs_dev.h"
+#include "esp_vfs_eventfd.h"
+#include "freertos/FreeRTOS.h"
+#include "freertos/task.h"
+#include "hal/timer_types.h"
+
+#define TIMER_DIVIDER         16
+#define TIMER_SCALE           (TIMER_BASE_CLK / TIMER_DIVIDER)
+#define MS_PER_S              1000
+#define TIMER_INTERVAL_SEC    2.5
+#define TEST_WITHOUT_RELOAD   0
+#define PROGRESS_INTERVAL_MS  3500
+#define TIMER_SIGNAL          1
+#define PROGRESS_SIGNAL       2
+
+static const char *TAG = "eventfd_example";
+
+int s_timer_fd;
+int s_progress_fd;
+
+static void IRAM_ATTR eventfd_timer_group0_isr(void *para)
+{
+    timer_spinlock_take(TIMER_GROUP_0);
+    int timer_idx = (int) para;
+
+    uint32_t timer_intr = timer_group_get_intr_status_in_isr(TIMER_GROUP_0);
+    uint64_t timer_counter_value = timer_group_get_counter_value_in_isr(TIMER_GROUP_0, timer_idx);
+
+    if (timer_intr & TIMER_INTR_T0) {
+        timer_group_clr_intr_status_in_isr(TIMER_GROUP_0, TIMER_0);
+        timer_counter_value += (uint64_t) (TIMER_INTERVAL_SEC * TIMER_SCALE);
+        timer_group_set_alarm_value_in_isr(TIMER_GROUP_0, timer_idx, timer_counter_value);
+    }
+
+    timer_group_enable_alarm_in_isr(TIMER_GROUP_0, timer_idx);
+
+    uint64_t signal = TIMER_SIGNAL;
+    ssize_t val = write(s_timer_fd, &signal, sizeof(signal));
+    assert(val == sizeof(signal));
+    timer_spinlock_give(TIMER_GROUP_0);
+}
+
+static void eventfd_timer_init(int timer_idx, double timer_interval_sec)
+{
+    timer_config_t config = {
+        .divider = TIMER_DIVIDER,
+        .counter_dir = TIMER_COUNT_UP,
+        .counter_en = TIMER_PAUSE,
+        .alarm_en = TIMER_ALARM_EN,
+        .auto_reload = false,
+    };
+    ESP_ERROR_CHECK(timer_init(TIMER_GROUP_0, timer_idx, &config));
+
+    ESP_ERROR_CHECK(timer_set_counter_value(TIMER_GROUP_0, timer_idx, 0x00000000ULL));
+
+    ESP_ERROR_CHECK(timer_set_alarm_value(TIMER_GROUP_0, timer_idx, timer_interval_sec * TIMER_SCALE));
+    ESP_ERROR_CHECK(timer_enable_intr(TIMER_GROUP_0, timer_idx));
+    ESP_ERROR_CHECK(timer_isr_register(TIMER_GROUP_0, timer_idx, eventfd_timer_group0_isr,
+                                       NULL, ESP_INTR_FLAG_IRAM, NULL));
+
+    ESP_ERROR_CHECK(timer_start(TIMER_GROUP_0, timer_idx));
+}
+
+static void worker_task(void *arg)
+{
+    while (true) {
+        vTaskDelay(pdMS_TO_TICKS(PROGRESS_INTERVAL_MS));
+        uint64_t signal = PROGRESS_SIGNAL;
+        ssize_t val = write(s_progress_fd, &signal, sizeof(signal));
+        assert(val == sizeof(signal));
+    }
+    vTaskDelete(NULL);
+}
+
+static void collector_task(void *arg)
+{
+    esp_vfs_eventfd_config_t config = {
+        .eventfd_max_num = 2,
+    };
+    ESP_ERROR_CHECK(esp_vfs_eventfd_register(&config));
+
+    s_timer_fd = eventfd(0, EFD_SUPPORT_ISR);
+    s_progress_fd = eventfd(0, 0);
+    assert(s_timer_fd > 0);
+    assert(s_progress_fd > 0);
+
+    int maxFd = s_progress_fd > s_timer_fd ? s_progress_fd : s_timer_fd;
+    int select_timeout_count = 0;
+    int timer_trigger_count = 0;
+    int progress_trigger_count = 0;
+
+    for (size_t i = 0; ; i++) {
+        struct timeval timeout;
+        uint64_t signal;
+
+        timeout.tv_sec = 2;
+        timeout.tv_usec = 0;
+
+        fd_set readfds;
+        FD_ZERO(&readfds);
+        FD_SET(s_timer_fd, &readfds);
+        FD_SET(s_progress_fd, &readfds);
+
+        int num_triggered = select(maxFd + 1, &readfds, NULL, NULL, &timeout);
+        assert(num_triggered >= 0);
+
+        uint64_t task_counter_value;
+        timer_get_counter_value(TIMER_GROUP_0, TIMER_0, &task_counter_value);
+        ESP_LOGI(TAG, "Time: %.2fs", (double)task_counter_value / TIMER_SCALE);
+
+        if (FD_ISSET(s_progress_fd, &readfds)) {
+            ssize_t ret = read(s_progress_fd, &signal, sizeof(signal));
+            assert(ret == sizeof(signal));
+            assert(signal == PROGRESS_SIGNAL);
+            progress_trigger_count++;
+            ESP_LOGI(TAG, "Progress fd event triggered");
+        }
+        if (FD_ISSET(s_timer_fd, &readfds)) {
+            ssize_t ret = read(s_timer_fd, &signal, sizeof(signal));
+            assert(ret == sizeof(signal));
+            assert(signal == TIMER_SIGNAL);
+            timer_trigger_count++;
+            ESP_LOGI(TAG, "TimerEvent fd event triggered");
+        }
+        if (num_triggered == 0) {
+            select_timeout_count++;
+            ESP_LOGI(TAG, "Select timeout");
+        }
+
+        if (i % 10 == 0) {
+            ESP_LOGI(TAG, "=================================");
+            ESP_LOGI(TAG, "Select timeouted for %d times", select_timeout_count);
+            ESP_LOGI(TAG, "Timer triggerred for %d times", timer_trigger_count);
+            ESP_LOGI(TAG, "Progress triggerred for %d times", progress_trigger_count);
+            ESP_LOGI(TAG, "=================================");
+
+        }
+    }
+
+    timer_deinit(TIMER_GROUP_0, TIMER_0);
+    close(s_timer_fd);
+    close(s_progress_fd);
+    esp_vfs_eventfd_unregister();
+    vTaskDelete(NULL);
+}
+
+void app_main(void)
+{
+    eventfd_timer_init(TIMER_0, TIMER_INTERVAL_SEC);
+    xTaskCreate(worker_task, "worker_task", 4 * 1024, NULL, 5, NULL);
+    xTaskCreate(collector_task, "collector_task", 4 * 1024, NULL, 5, NULL);
+}