systimer: support etm event

components/esp_timer/src/esp_timer_etm.c

@@ -0,0 +1,46 @@
+/*
+ * SPDX-FileCopyrightText: 2022 Espressif Systems (Shanghai) CO LTD
+ *
+ * SPDX-License-Identifier: Apache-2.0
+ */
+
+#include "esp_log.h"
+#include "esp_check.h"
+#include "esp_heap_caps.h"
+#include "esp_timer.h"
+#include "soc/soc_etm_source.h"
+#include "hal/systimer_ll.h"
+#include "esp_private/etm_interface.h"
+
+#define ETM_MEM_ALLOC_CAPS   MALLOC_CAP_DEFAULT
+
+static const char *TAG = "esptimer-etm";
+
+static esp_err_t esp_timer_etm_event_del(esp_etm_event_t *event)
+{
+    free(event);
+    return ESP_OK;
+}
+
+esp_err_t esp_timer_new_etm_alarm_event(esp_etm_event_handle_t *out_event)
+{
+    esp_etm_event_t *event = NULL;
+    esp_err_t ret = ESP_OK;
+    ESP_GOTO_ON_FALSE(out_event, ESP_ERR_INVALID_ARG, err, TAG, "invalid argument");
+    event = heap_caps_calloc(1, sizeof(esp_etm_event_t), ETM_MEM_ALLOC_CAPS);
+    ESP_GOTO_ON_FALSE(event, ESP_ERR_NO_MEM, err, TAG, "no memory for ETM event");
+
+    // fill the ETM event object
+    uint32_t event_id = SYSTIMER_EVT_CNT_CMP0 + SYSTIMER_LL_ALARM_CLOCK;
+    event->event_id = event_id;
+    event->trig_periph = ETM_TRIG_PERIPH_SYSTIMER;
+    event->del = esp_timer_etm_event_del;
+    *out_event = event;
+    return ESP_OK;
+
+err:
+    if (event) {
+        esp_timer_etm_event_del(event);
+    }
+    return ret;
+}