Fixed ESP32 EMAC driver insufficient TX buffer size which could followed esp_eth_stop and esp_eth_start sequence

components/hal/esp32/include/hal/emac.h

@@ -1,16 +1,8 @@
-// Copyright 2019 Espressif Systems (Shanghai) PTE LTD
-//
-// Licensed under the Apache License, Version 2.0 (the "License");
-// you may not use this file except in compliance with the License.
-// You may obtain a copy of the License at
-//
-//     http://www.apache.org/licenses/LICENSE-2.0
-//
-// Unless required by applicable law or agreed to in writing, software
-// distributed under the License is distributed on an "AS IS" BASIS,
-// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
-// See the License for the specific language governing permissions and
-// limitations under the License.
+/*
+ * SPDX-FileCopyrightText: 2021 Espressif Systems (Shanghai) CO LTD
+ *
+ * SPDX-License-Identifier: Apache-2.0
+ */
 
 #pragma once
 
@@ -381,9 +373,24 @@ uint32_t emac_hal_get_phy_data(emac_hal_context_t *hal);
 
 void emac_hal_set_address(emac_hal_context_t *hal, uint8_t *mac_addr);
 
+
+/**
+ * @brief Starts EMAC Transmission & Reception
+ *
+ * @param hal EMAC HAL context infostructure
+ */
 void emac_hal_start(emac_hal_context_t *hal);
 
-void emac_hal_stop(emac_hal_context_t *hal);
+/**
+ * @brief Stops EMAC Transmission & Reception
+ *
+ * @param hal EMAC HAL context infostructure
+ * @return
+ *     - ESP_OK: succeed
+  *    - ESP_ERR_INVALID_STATE: previous frame transmission is not completed. When this error occurs,
+  *      wait and reapeat the EMAC stop again.
+ */
+esp_err_t emac_hal_stop(emac_hal_context_t *hal);
 
 uint32_t emac_hal_get_tx_desc_owner(emac_hal_context_t *hal);