feat(esp_trace): extend encoder interface

Add esp_trace_flush, esp_trace_start and esp_trace_stop APIs

components/esp_trace/README.md

@@ -33,11 +33,12 @@ end
 %% =======================
 subgraph PRIMARY["🔌 PUBLIC INTERFACE"]
     api["- esp_trace.h 
-    - esp_trace_init()
-    - esp_trace_record()
     - esp_trace_write()
+    - esp_trace_start()
+    - esp_trace_stop()
     - esp_trace_flush()
-    - esp_trace_print()"]
+    - esp_trace_is_host_connected()
+    - esp_trace_get_link_type()"]
 end
 
 %% wiring: App uses API (labels land on the short pre-edges to api_in)
@@ -203,7 +204,7 @@ idf_component_register(
 )
 ```
 
-This means you can directly use both the trace library APIs (e.g., SystemView) and `esp_trace` APIs (like `esp_trace_get_user_params()`, `esp_trace_is_host_connected()`, etc.) without explicitly declaring the dependency.
+This means you can directly use both the trace library APIs (e.g., SystemView) and `esp_trace` APIs (like `esp_trace_get_user_params()`, `esp_trace_is_host_connected()`, `esp_trace_start()` / `esp_trace_stop()` / `esp_trace_flush()`, etc.) without explicitly declaring the dependency.
 
 ### When Using Standalone Apptrace
 

components/esp_trace/include/esp_trace.h

@@ -1,5 +1,5 @@
 /*
- * SPDX-FileCopyrightText: 2025 Espressif Systems (Shanghai) CO LTD
+ * SPDX-FileCopyrightText: 2025-2026 Espressif Systems (Shanghai) CO LTD
  *
  * SPDX-License-Identifier: Apache-2.0
  */
@@ -100,6 +100,27 @@ esp_trace_handle_t esp_trace_get_active_handle(void);
  */
 esp_err_t esp_trace_write(esp_trace_handle_t handle, const void *data, size_t size, unsigned long tmo);
 
+/**
+ * @brief Resume trace event emission on the active session.
+ *
+ * @return ESP_OK on success, otherwise see esp_err_t
+ */
+esp_err_t esp_trace_start(void);
+
+/**
+ * @brief Pause trace event emission on the active session.
+ *
+ * @return ESP_OK on success, otherwise see esp_err_t
+ */
+esp_err_t esp_trace_stop(void);
+
+/**
+ * @brief Flush pending trace data through the encoder
+ *
+ * @return ESP_OK on success, otherwise see esp_err_t
+ */
+esp_err_t esp_trace_flush(void);
+
 /**
  * @brief Check if the host is connected
  *

components/esp_trace/include/esp_trace_port_encoder.h

@@ -1,5 +1,5 @@
 /*
- * SPDX-FileCopyrightText: 2025 Espressif Systems (Shanghai) CO LTD
+ * SPDX-FileCopyrightText: 2025-2026 Espressif Systems (Shanghai) CO LTD
  *
  * SPDX-License-Identifier: Apache-2.0
  */
@@ -49,8 +49,20 @@ typedef struct {
      */
     void (*panic_handler)(esp_trace_encoder_t *enc, const void *info);
 
+    /** @brief Resume trace event emission */
+    esp_err_t (*start)(esp_trace_encoder_t *enc);
+
+    /** @brief Pause trace event emission */
+    esp_err_t (*stop)(esp_trace_encoder_t *enc);
+
+    /** @brief Flush pending trace data through the encoder */
+    esp_err_t (*flush)(esp_trace_encoder_t *enc);
+
     /**
-     * @brief Take encoder lock
+     * @brief Take encoder lock.
+     *        Callers should pass ESP_TRACE_TMO_INFINITE unless they explicitly
+     *        check the return value — pairing a failed take with give_lock()
+     *        causes a spinlock owner-mismatch assert.
      * @param enc Encoder instance
      * @param tmo Timeout in microseconds
      * @return Lock state (for recursive locking) or 0 on failure

components/esp_trace/src/core/esp_trace_core.c

@@ -151,6 +151,48 @@ esp_err_t esp_trace_write(esp_trace_handle_t h, const void *data, size_t size, u
     return h->encoder.vt->write(&h->encoder, data, size, tmo);
 }
 
+esp_err_t esp_trace_start(void)
+{
+    esp_trace_handle_t h = s_active_handle;
+    if (!h) {
+        return ESP_ERR_INVALID_STATE;
+    }
+
+    if (!h->encoder.vt->start) {
+        return ESP_ERR_NOT_SUPPORTED;
+    }
+
+    return h->encoder.vt->start(&h->encoder);
+}
+
+esp_err_t esp_trace_stop(void)
+{
+    esp_trace_handle_t h = s_active_handle;
+    if (!h) {
+        return ESP_ERR_INVALID_STATE;
+    }
+
+    if (!h->encoder.vt->stop) {
+        return ESP_ERR_NOT_SUPPORTED;
+    }
+
+    return h->encoder.vt->stop(&h->encoder);
+}
+
+esp_err_t esp_trace_flush(void)
+{
+    esp_trace_handle_t h = s_active_handle;
+    if (!h) {
+        return ESP_ERR_INVALID_STATE;
+    }
+
+    if (!h->encoder.vt->flush) {
+        return ESP_ERR_NOT_SUPPORTED;
+    }
+
+    return h->encoder.vt->flush(&h->encoder);
+}
+
 bool esp_trace_is_host_connected(esp_trace_handle_t h)
 {
     if (!h || !h->transport.vt || !h->transport.vt->is_host_connected) {