ESP8266: handles reset ready as OOB

Makes possible to recover from spurious resets addiotionally to planned
ones.

Author: Veijo Pesonen

components/wifi/esp8266-driver/ESP8266/ESP8266.cpp

@@ -25,6 +25,7 @@
 #include "PinNames.h"
 #include "platform/Callback.h"
 #include "platform/mbed_error.h"
+#include "rtos/Kernel.h"
 
 #define TRACE_GROUP  "ESPA" // ESP8266 AT layer
 
@@ -51,6 +52,8 @@ ESP8266::ESP8266(PinName tx, PinName rx, bool debug, PinName rts, PinName cts)
       _sock_already(false),
       _closed(false),
       _busy(false),
+      _reset_check(_rmutex),
+      _reset_done(false),
       _conn_status(NSAPI_STATUS_DISCONNECTED)
 {
     _serial.set_baud(ESP8266_DEFAULT_BAUD_RATE);
@@ -71,6 +74,7 @@ ESP8266::ESP8266(PinName tx, PinName rx, bool debug, PinName rts, PinName cts)
     _parser.oob("UNLINK", callback(this, &ESP8266::_oob_socket_close_err));
     _parser.oob("ALREADY CONNECTED", callback(this, &ESP8266::_oob_conn_already));
     _parser.oob("ERROR", callback(this, &ESP8266::_oob_err));
+    _parser.oob("ready", callback(this, &ESP8266::_oob_reset));
     // Don't expect to find anything about the watchdog reset in official documentation
     //https://techtutorialsx.com/2017/01/21/esp8266-watchdog-functions/
     _parser.oob("wdt reset", callback(this, &ESP8266::_oob_watchdog_reset));
@@ -234,20 +238,31 @@ bool ESP8266::startup(int mode)
 
 bool ESP8266::reset(void)
 {
+    static const int ESP8266_BOOTTIME = 10000; // [ms]
     bool done = false;
 
     _smutex.lock();
-    set_timeout(ESP8266_CONNECT_TIMEOUT);
 
-    for (int i = 0; i < 2; i++) {
-        if (_parser.send("AT+RST")
-                && _parser.recv("OK\n")
-                && _parser.recv("ready")) {
-            done = true;
-            break;
-        }
+    unsigned long int start_time = rtos::Kernel::get_ms_count();
+    _reset_done = false;
+    set_timeout(ESP8266_RECV_TIMEOUT);
+    if (!_parser.send("AT+RST") || !_parser.recv("OK\n")) {
+        tr_debug("reset(): AT+RST failed or no response");
+        goto EXIT;
     }
 
+    _rmutex.lock();
+    while ((rtos::Kernel::get_ms_count() - start_time < ESP8266_BOOTTIME) && !_reset_done) {
+        _process_oob(ESP8266_RECV_TIMEOUT, true); // UART mutex claimed -> need to check for OOBs ourselves
+        _reset_check.wait_for(100); // Arbitrary relatively short delay
+    }
+
+    done = _reset_done;
+    _rmutex.unlock();
+
+    tr_debug("reset(): done: %s", done ? "OK" : "FAIL");
+
+EXIT:
     _clear_socket_packets(ESP8266_ALL_SOCKET_IDS);
     set_timeout();
     _smutex.unlock();
@@ -963,6 +978,25 @@ void ESP8266::_oob_watchdog_reset()
                "_oob_watchdog_reset() modem watchdog reset triggered\n");
 }
 
+void ESP8266::_oob_reset()
+{
+
+    _rmutex.lock();
+    _reset_done = true;
+    _reset_check.notify_all();
+    _rmutex.unlock();
+
+    for (int i = 0; i < SOCKET_COUNT; i++) {
+        _sock_i[i].open = false;
+    }
+
+    // Makes possible to reinitialize
+    _conn_status = NSAPI_STATUS_ERROR_UNSUPPORTED;
+    _conn_stat_cb();
+
+    tr_debug("_oob_reset(): reset detected");
+}
+
 void ESP8266::_oob_busy()
 {
     char status[5];

components/wifi/esp8266-driver/ESP8266/ESP8266.h

@@ -27,6 +27,7 @@
 #include "platform/ATCmdParser.h"
 #include "platform/Callback.h"
 #include "platform/mbed_error.h"
+#include "rtos/ConditionVariable.h"
 #include "rtos/Mutex.h"
 
 // Various timeouts for different ESP8266 operations
@@ -396,6 +397,7 @@ class ESP8266 {
     PinName _serial_rts;
     PinName _serial_cts;
     rtos::Mutex _smutex; // Protect serial port access
+    rtos::Mutex _rmutex; // Reset protection
 
     // AT Command Parser
     mbed::ATCmdParser _parser;
@@ -435,6 +437,7 @@ class ESP8266 {
     void _oob_watchdog_reset();
     void _oob_busy();
     void _oob_tcp_data_hdlr();
+    void _oob_reset();
 
     // OOB state variables
     int _connect_error;
@@ -444,6 +447,8 @@ class ESP8266 {
     bool _closed;
     bool _error;
     bool _busy;
+    rtos::ConditionVariable _reset_check;
+    bool _reset_done;
 
     // Modem's address info
     char _ip_buffer[16];

components/wifi/esp8266-driver/ESP8266Interface.cpp

@@ -577,6 +577,10 @@ int ESP8266Interface::socket_send(void *handle, const void *data, unsigned size)
         return NSAPI_ERROR_NO_SOCKET;
     }
 
+    if (!_sock_i[socket->id].open) {
+        return NSAPI_ERROR_CONNECTION_LOST;
+    }
+
     if (!size) {
         // Firmware limitation
         return socket->proto == NSAPI_TCP ? 0 : NSAPI_ERROR_UNSUPPORTED;
@@ -604,6 +608,10 @@ int ESP8266Interface::socket_recv(void *handle, void *data, unsigned size)
         return NSAPI_ERROR_NO_SOCKET;
     }
 
+    if (!_sock_i[socket->id].open) {
+        return NSAPI_ERROR_CONNECTION_LOST;
+    }
+
     int32_t recv;
     if (socket->proto == NSAPI_TCP) {
         recv = _esp.recv_tcp(socket->id, data, size);
@@ -791,6 +799,10 @@ void ESP8266Interface::update_conn_state_cb()
         default:
             _initialized = false;
             _conn_stat = NSAPI_STATUS_DISCONNECTED;
+            for (int i = 0; i < ESP8266_SOCKET_COUNT; i++) {
+                _sock_i[i].open = false;
+                _sock_i[i].sport = 0;
+            }
     }
 
     // Inform upper layers