modem: support modem facility and PPPoS

1. add support for ESP32 DTE
2. add support for SIM800/BG96 DCE
3. add PPPoS setup procedure
4. add support for SMS
5. add mqtt example after PPP connection established

examples/protocols/pppos_client/components/modem/include/esp_modem.h

@@ -0,0 +1,137 @@
+// Copyright 2015-2018 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.
+#pragma once
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+#include "esp_modem_dce.h"
+#include "esp_modem_dte.h"
+#include "esp_event.h"
+#include "driver/uart.h"
+
+/**
+ * @brief Declare Event Base for ESP Modem
+ *
+ */
+ESP_EVENT_DECLARE_BASE(ESP_MODEM_EVENT);
+
+/**
+ * @brief ESP Modem Event
+ *
+ */
+typedef enum {
+    MODEM_EVENT_PPP_START,      /*!< ESP Modem Start PPP Session */
+    MODEM_EVENT_PPP_CONNECT,    /*!< ESP Modem Connect to PPP Server */
+    MODEM_EVENT_PPP_DISCONNECT, /*!< ESP Modem Disconnect from PPP Server */
+    MODEM_EVENT_PPP_STOP,       /*!< ESP Modem Stop PPP Session*/
+    MODEM_EVENT_UNKNOWN         /*!< ESP Modem Unknown Response */
+} esp_modem_event_t;
+
+/**
+ * @brief ESP Modem DTE Configuration
+ *
+ */
+typedef struct {
+    uart_port_t port_num;           /*!< UART port number */
+    uart_word_length_t data_bits;   /*!< Data bits of UART */
+    uart_stop_bits_t stop_bits;     /*!< Stop bits of UART */
+    uart_parity_t parity;           /*!< Parity type */
+    modem_flow_ctrl_t flow_control; /*!< Flow control type */
+    uint32_t baud_rate;             /*!< Communication baud rate */
+} esp_modem_dte_config_t;
+
+/**
+ * @brief ESP Modem DTE Default Configuration
+ *
+ */
+#define ESP_MODEM_DTE_DEFAULT_CONFIG()          \
+    {                                           \
+        .port_num = UART_NUM_1,                 \
+        .data_bits = UART_DATA_8_BITS,          \
+        .stop_bits = UART_STOP_BITS_1,          \
+        .parity = UART_PARITY_DISABLE,          \
+        .baud_rate = 115200,                    \
+        .flow_control = MODEM_FLOW_CONTROL_NONE \
+    }
+
+/**
+ * @brief Create and initialize Modem DTE object
+ *
+ * @param config configuration of ESP Modem DTE object
+ * @return modem_dte_t*
+ *      - Modem DTE object
+ */
+modem_dte_t *esp_modem_dte_init(const esp_modem_dte_config_t *config);
+
+/**
+ * @brief Register event handler for ESP Modem event loop
+ *
+ * @param dte modem_dte_t type object
+ * @param handler event handler to register
+ * @param handler_args arguments for registered handler
+ * @return esp_err_t
+ *      - ESP_OK on success
+ *      - ESP_ERR_NO_MEM on allocating memory for the handler failed
+ *      - ESP_ERR_INVALID_ARG on invalid combination of event base and event id
+ */
+esp_err_t esp_modem_add_event_handler(modem_dte_t *dte, esp_event_handler_t handler, void *handler_args);
+
+/**
+ * @brief Unregister event handler for ESP Modem event loop
+ *
+ * @param dte modem_dte_t type object
+ * @param handler event handler to unregister
+ * @return esp_err_t
+ *      - ESP_OK on success
+ *      - ESP_ERR_INVALID_ARG on invalid combination of event base and event id
+ */
+esp_err_t esp_modem_remove_event_handler(modem_dte_t *dte, esp_event_handler_t handler);
+
+/**
+ * @brief PPPoS Client IP Information
+ *
+ */
+typedef struct {
+    ip4_addr_t ip;      /*!< IP Address */
+    ip4_addr_t netmask; /*!< Net Mask */
+    ip4_addr_t gw;      /*!< Gateway */
+    ip4_addr_t ns1;     /*!< Name Server1 */
+    ip4_addr_t ns2;     /*!< Name Server2 */
+} ppp_client_ip_info_t;
+
+/**
+ * @brief Setup PPP Session
+ *
+ * @param dte Modem DTE object
+ * @return esp_err_t
+ *      - ESP_OK on success
+ *      - ESP_FAIL on error
+ */
+esp_err_t esp_modem_setup_ppp(modem_dte_t *dte);
+
+/**
+ * @brief Exit PPP Session
+ *
+ * @param dte Modem DTE Object
+ * @return esp_err_t
+ *      - ESP_OK on success
+ *      - ESP_FAIL on error
+ */
+esp_err_t esp_modem_exit_ppp(modem_dte_t *dte);
+
+#ifdef __cplusplus
+}
+#endif