Deduplicate NRF52 startOTAUpdate()

The startOTAUpdate() is the same for all NRF52 boards. Use a common
implementation for all boards that currently have a specific
implementation.

The following boards currently have an empty startOTAUpdate() for
whatever reasons and therefore are not inheriting NRF52BoardOTA to
keep the same state: Nano G2 Ultra, Seeed SenseCAP T1000-E,
Wio WM1110.

Signed-off-by: Frieder Schrempf <frieder@fris.de>

src/helpers/NRF52Board.cpp

@@ -1,6 +1,22 @@
 #if defined(NRF52_PLATFORM)
 #include "NRF52Board.h"
 
+#include <bluefruit.h>
+
+static BLEDfu bledfu;
+
+static void connect_callback(uint16_t conn_handle) {
+  (void)conn_handle;
+  MESH_DEBUG_PRINTLN("BLE client connected");
+}
+
+static void disconnect_callback(uint16_t conn_handle, uint8_t reason) {
+  (void)conn_handle;
+  (void)reason;
+
+  MESH_DEBUG_PRINTLN("BLE client disconnected");
+}
+
 void NRF52Board::begin() {
   startup_reason = BD_STARTUP_NORMAL;
 }
@@ -37,4 +53,52 @@ float NRF52Board::getMCUTemperature() {
 
   return temp * 0.25f; // Convert to *C
 }
+
+bool NRF52BoardOTA::startOTAUpdate(const char *id, char reply[]) {
+  // Config the peripheral connection with maximum bandwidth
+  // more SRAM required by SoftDevice
+  // Note: All config***() function must be called before begin()
+  Bluefruit.configPrphBandwidth(BANDWIDTH_MAX);
+  Bluefruit.configPrphConn(92, BLE_GAP_EVENT_LENGTH_MIN, 16, 16);
+
+  Bluefruit.begin(1, 0);
+  // Set max power. Accepted values are: -40, -30, -20, -16, -12, -8, -4, 0, 4
+  Bluefruit.setTxPower(4);
+  // Set the BLE device name
+  Bluefruit.setName(ota_name);
+
+  Bluefruit.Periph.setConnectCallback(connect_callback);
+  Bluefruit.Periph.setDisconnectCallback(disconnect_callback);
+
+  // To be consistent OTA DFU should be added first if it exists
+  bledfu.begin();
+
+  // Set up and start advertising
+  // Advertising packet
+  Bluefruit.Advertising.addFlags(BLE_GAP_ADV_FLAGS_LE_ONLY_GENERAL_DISC_MODE);
+  Bluefruit.Advertising.addTxPower();
+  Bluefruit.Advertising.addName();
+
+  /* Start Advertising
+    - Enable auto advertising if disconnected
+    - Interval:  fast mode = 20 ms, slow mode = 152.5 ms
+    - Timeout for fast mode is 30 seconds
+    - Start(timeout) with timeout = 0 will advertise forever (until connected)
+
+    For recommended advertising interval
+    https://developer.apple.com/library/content/qa/qa1931/_index.html
+  */
+  Bluefruit.Advertising.restartOnDisconnect(true);
+  Bluefruit.Advertising.setInterval(32, 244); // in unit of 0.625 ms
+  Bluefruit.Advertising.setFastTimeout(30);   // number of seconds in fast mode
+  Bluefruit.Advertising.start(0);             // 0 = Don't stop advertising after n seconds
+
+  uint8_t mac_addr[6];
+  memset(mac_addr, 0, sizeof(mac_addr));
+  Bluefruit.getAddr(mac_addr);
+  sprintf(reply, "OK - mac: %02X:%02X:%02X:%02X:%02X:%02X", mac_addr[5], mac_addr[4], mac_addr[3],
+          mac_addr[2], mac_addr[1], mac_addr[0]);
+
+  return true;
+}
 #endif

src/helpers/NRF52Board.h

@@ -27,4 +27,13 @@ class NRF52BoardDCDC : virtual public NRF52Board {
 public:
   virtual void begin() override;
 };
+
+class NRF52BoardOTA : virtual public NRF52Board {
+private:
+  char *ota_name;
+
+public:
+  NRF52BoardOTA(char *name) : ota_name(name) {}
+  virtual bool startOTAUpdate(const char *id, char reply[]) override;
+};
 #endif