esp_modem: Dual DTE support

Modems can expose 2 terminals, which can be used simultaneously.
One for AT commands, the other one for data.

components/esp_modem/idf_component.yml

@@ -1,4 +1,4 @@
-version: "0.1.27"
+version: "0.1.28"
 description: esp modem
 url: https://github.com/espressif/esp-protocols/tree/master/components/esp_modem
 dependencies:

components/esp_modem/include/cxx_include/esp_modem_dte.hpp

@@ -39,9 +39,12 @@ public:
      * @brief Creates a DTE instance from the terminal
      * @param config DTE config structure
      * @param t unique-ptr to Terminal
+     * @param s unique-ptr to secondary Terminal
      */
     explicit DTE(const esp_modem_dte_config *config, std::unique_ptr<Terminal> t);
     explicit DTE(std::unique_ptr<Terminal> t);
+    explicit DTE(const esp_modem_dte_config *config, std::unique_ptr<Terminal> t, std::unique_ptr<Terminal> s);
+    explicit DTE(std::unique_ptr<Terminal> t, std::unique_ptr<Terminal> s);
 
     ~DTE() = default;
 

components/esp_modem/include/cxx_include/esp_modem_types.hpp

@@ -27,8 +27,9 @@ namespace esp_modem {
  */
 enum class modem_mode {
     UNDEF,
-    COMMAND_MODE, /*!< Command mode -- the modem is supposed to send AT commands in this mode  */
+    COMMAND_MODE, /*!< Command mode -- the modem is supposed to send AT commands in this mode */
     DATA_MODE,    /*!< Data mode -- the modem communicates with network interface on PPP protocol */
+    DUAL_MODE,    /*!< Dual mode -- the modem has two real terminals. Data and commands work at the same time */
     CMUX_MODE,    /*!< CMUX (Multiplex mode) -- Simplified CMUX mode, which creates two virtual terminals,
                    *  assigning one solely to command interface and the other  to the data mode */
     CMUX_MANUAL_MODE,    /*!< Enter CMUX mode manually -- just creates two virtual terminals */

components/esp_modem/src/esp_modem_dce.cpp

@@ -88,6 +88,7 @@ bool DCE_Mode::set_unsafe(DTE *dte, ModuleIf *device, Netif &netif, modem_mode m
 {
     switch (m) {
     case modem_mode::UNDEF:
+    case modem_mode::DUAL_MODE: // Only DTE can be in Dual mode
         break;
     case modem_mode::COMMAND_MODE:
         if (mode == modem_mode::COMMAND_MODE || mode >= modem_mode::CMUX_MANUAL_MODE) {

components/esp_modem/src/esp_modem_dte.cpp

@@ -24,6 +24,16 @@ DTE::DTE(std::unique_ptr<Terminal> terminal):
     cmux_term(nullptr), primary_term(std::move(terminal)), secondary_term(primary_term),
     mode(modem_mode::UNDEF) {}
 
+DTE::DTE(const esp_modem_dte_config *config, std::unique_ptr<Terminal> t, std::unique_ptr<Terminal> s):
+    buffer(config->dte_buffer_size),
+    cmux_term(nullptr), primary_term(std::move(t)), secondary_term(std::move(s)),
+    mode(modem_mode::DUAL_MODE) {}
+
+DTE::DTE(std::unique_ptr<Terminal> t, std::unique_ptr<Terminal> s):
+    buffer(dte_default_buffer_size),
+    cmux_term(nullptr), primary_term(std::move(t)), secondary_term(std::move(s)),
+    mode(modem_mode::DUAL_MODE) {}
+
 command_result DTE::command(const std::string &command, got_line_cb got_line, uint32_t time_ms, const char separator)
 {
     Scoped<Lock> l(internal_lock);
@@ -104,9 +114,9 @@ bool DTE::set_mode(modem_mode m)
             return false;
         }
     }
-    // transitions (COMMAND|CMUX|UNDEF) -> DATA
+    // transitions (COMMAND|DUAL|CMUX|UNDEF) -> DATA
     if (m == modem_mode::DATA_MODE) {
-        if (mode == modem_mode::CMUX_MODE || mode == modem_mode::CMUX_MANUAL_MODE) {
+        if (mode == modem_mode::CMUX_MODE || mode == modem_mode::CMUX_MANUAL_MODE || mode == modem_mode::DUAL_MODE) {
             // mode stays the same, but need to swap terminals (as command has been switched)
             secondary_term.swap(primary_term);
         } else {
@@ -114,7 +124,7 @@ bool DTE::set_mode(modem_mode m)
         }
         return true;
     }
-    // transitions (DATA|CMUX|UNDEF) -> COMMAND
+    // transitions (DATA|DUAL|CMUX|UNDEF) -> COMMAND
     if (m == modem_mode::COMMAND_MODE) {
         if (mode == modem_mode::CMUX_MODE) {
             if (exit_cmux()) {
@@ -123,7 +133,7 @@ bool DTE::set_mode(modem_mode m)
             }
             mode = modem_mode::UNDEF;
             return false;
-        } if (mode == modem_mode::CMUX_MANUAL_MODE) {
+        } if (mode == modem_mode::CMUX_MANUAL_MODE || mode == modem_mode::DUAL_MODE) {
             return true;
         } else {
             mode = m;