Make the component compatible with IDFv4.1, v4.2, v4.3

components/esp_modem/examples/ap_to_pppos/README.md

@@ -15,3 +15,7 @@ By default, this example simply connects to the PPP server using a supported dev
 This example however, doesn't rely on sending specific AT commands, just the bare minimum to setup the cellular network.
 Thus, if the `EXAMPLE_USE_MINIMAL_DCE` option is enabled, we directly inherit from the `ModuleIf` and implement only the basic commands.
 Also, to demonstrate the dce_factory functionality, a new `NetDCE_Factory` is implemented for creating the network module and the DCE.
+
+### Supported IDF versions
+
+This example is only supported from `v4.2`, since is uses NAPT feature. 

components/esp_modem/examples/linux_modem/README.md

@@ -17,3 +17,7 @@ over PPPoS, i.e. over the modem serial line.
 * Experiment with the network, after getting the IP from the modem device
     - directly in the code
     - in the system (need to set `tun` interface IP, dns servers, and routing the desired traffic over the tun interface)
+
+### Supported IDF versions
+
+This example (using the default CMake IDF build system) is only supported from `v4.4`, since is uses `idf.py`'s linux target.  

components/esp_modem/examples/modem_console/README.md

@@ -15,3 +15,7 @@ To demonstrate creating custom modem devices, this example creates a DCE object
 that sets up the DCE based on a custom module implemented in the `my_module_dce.hpp` file. The module class only overrides
 `get_module_name()` method supplying a user defined name, but keeps all other commands the same as defined in the `GenericModule`
 class.
+
+### Supported IDF versions
+
+This example is only supported from `v4.2`, due to support of the console repl mode. 

components/esp_modem/examples/pppos_client/README.md

@@ -8,3 +8,7 @@ This example shows how to act as a MQTT client after the PPPoS channel created b
 ## How to use this example
 
 See the README.md file in the upper level `pppos` directory for more information about the PPPoS examples.
+
+### Supported IDF versions
+
+This example is only supported from `v4.1`, as this is the default dependency of `esp-modem` component. 

components/esp_modem/examples/simple_cmux_client/README.md

@@ -15,3 +15,7 @@ The example uses the following configuration options to demonstrate basic esp-mo
 ## About the esp_modem
 
 Please check the component [README](../../README.md)
+
+### Supported IDF versions
+
+This example is only supported from `v4.3`, since is uses an experimental `esp_event_cxx` component.

components/esp_modem/include/cxx_include/esp_modem_primitives.hpp

@@ -14,6 +14,8 @@
 
 #ifndef _ESP_MODEM_PRIMITIVES_HPP_
 #define _ESP_MODEM_PRIMITIVES_HPP_
+
+#include "esp_event.h"
 #include "esp_modem_exception.hpp"
 
 #if defined(CONFIG_IDF_TARGET_LINUX)
@@ -34,7 +36,7 @@ namespace esp_modem {
 using TaskFunction_t = void (*)(void*);
 #if !defined(CONFIG_IDF_TARGET_LINUX)
 struct Lock {
-    using MutexT = QueueDefinition*;
+    using MutexT = QueueHandle_t;
     explicit Lock();
     ~Lock();
     void lock();

components/esp_modem/port/linux/esp_event_mock/include/esp_event.h

@@ -38,4 +38,6 @@ esp_err_t esp_event_handler_register(const char * event_base, int32_t event_id,
 
 esp_err_t esp_event_handler_unregister(const char * event_base, int32_t event_id, void* event_handler);
 
+typedef void * QueueHandle_t;
+
 #endif //MDNS_HOST_ESP_EVENT_H

components/esp_modem/private_include/uart_compat.h

@@ -0,0 +1,35 @@
+// Copyright 2021 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.
+
+#include "esp_log.h"
+#include "driver/uart.h"
+
+#ifndef _UART_COMPAT_H_
+#define _UART_COMPAT_H_
+
+/**
+ * @brief This is a compatible header, which just takes care of different data ptr type
+ * across different IDF version in driver/uart
+ */
+static inline int uart_write_bytes_compat(uart_port_t uart_num, const void* src, size_t size)
+{
+#if ESP_IDF_VERSION_MAJOR >= 4 && ESP_IDF_VERSION_MINOR >= 3
+    const void *data = src;
+#else
+    auto *data = reinterpret_cast<const char*>(src);
+#endif
+    return uart_write_bytes(uart_num, data, size);
+}
+
+#endif //_UART_COMPAT_H_

components/esp_modem/private_include/uart_resource.hpp

@@ -26,8 +26,10 @@ namespace esp_modem {
  * @brief Uart Resource is a platform specific struct which is implemented separately for ESP_PLATFORM and linux target
  */
 struct uart_resource {
-    explicit uart_resource(const esp_modem_dte_config *config, struct QueueDefinition** event_queue, int fd);
+    explicit uart_resource(const esp_modem_dte_config *config, QueueHandle_t* event_queue, int fd);
+
     ~uart_resource();
+
     uart_port_t port{};
 };
 

components/esp_modem/src/esp_modem_term_uart.cpp

@@ -25,7 +25,7 @@ uart_resource::~uart_resource()
     }
 }
 
-uart_resource::uart_resource(const esp_modem_dte_config *config, struct QueueDefinition** event_queue, int fd)
+uart_resource::uart_resource(const esp_modem_dte_config *config, QueueHandle_t* event_queue, int fd)
     :port(-1)
 {
     esp_err_t res;

components/esp_modem/src/esp_modem_uart.cpp

@@ -17,6 +17,7 @@
 #include "freertos/semphr.h"
 #include "esp_log.h"
 #include "driver/uart.h"
+#include "uart_compat.h"
 #include "esp_modem_config.h"
 #include "exception_stub.hpp"
 #include "cxx_include/esp_modem_dte.hpp"
@@ -163,7 +164,8 @@ void UartTerminal::task() {
     }
 }
 
-int UartTerminal::read(uint8_t *data, size_t len) {
+int UartTerminal::read(uint8_t *data, size_t len)
+{
     size_t length = 0;
     uart_get_buffered_data_len(uart.port, &length);
     length = std::min(len, length);
@@ -173,8 +175,9 @@ int UartTerminal::read(uint8_t *data, size_t len) {
     return 0;
 }
 
-int UartTerminal::write(uint8_t *data, size_t len) {
+int UartTerminal::write(uint8_t *data, size_t len)
-    return uart_write_bytes(uart.port, data, len);
+{
+    return uart_write_bytes_compat(uart.port, data, len);
 }
 
 } // namespace esp_modem

components/esp_modem/src/esp_modem_uart_linux.cpp

@@ -23,7 +23,7 @@ namespace esp_modem {
 
 constexpr const char *TAG = "uart_resource";
 
-uart_resource::uart_resource(const esp_modem_dte_config *config, struct QueueDefinition** event_queue, int fd): port(-1)
+uart_resource::uart_resource(const esp_modem_dte_config *config, QueueHandle_t* event_queue, int fd): port(-1)
 {
     ESP_LOGD(TAG, "Creating uart resource" );
     struct termios tty = {};