fix: ArduinoOTA init, reporter mutex, BLE lock scope, NVS type

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

firmware/src/ble_scanner.cpp

@@ -5,11 +5,12 @@
 #include <NimBLEAdvertisedDevice.h>
 #include "mbedtls/md.h"
 #include <map>
+#include <mutex>
 
 #define RSSI_NEAR -65
 #define RSSI_MID  -80
 
-static portMUX_TYPE s_mux = portMUX_INITIALIZER_UNLOCKED;
+static std::mutex s_mutex;
 
 struct DeviceObs {
     int rssi_sum;
@@ -47,7 +48,7 @@ class ScanCallback : public NimBLEAdvertisedDeviceCallbacks {
         String hash = sha256_prefix(mac);
         int    rssi = dev->getRSSI();
 
-        portENTER_CRITICAL(&s_mux);
+        std::lock_guard<std::mutex> lock(s_mutex);
         auto it = s_seen.find(hash);
         if (it == s_seen.end()) {
             s_seen[hash] = {rssi, 1};
@@ -57,7 +58,6 @@ class ScanCallback : public NimBLEAdvertisedDeviceCallbacks {
         }
         int concurrent = (int)s_seen.size();
         if (concurrent > s_max_concurrent) s_max_concurrent = concurrent;
-        portEXIT_CRITICAL(&s_mux);
     }
 };
 
@@ -79,26 +79,30 @@ void ble_scanner_pause() { if (s_scan) s_scan->stop(); }
 void ble_scanner_resume() { if (s_scan) s_scan->start(0, nullptr, false); }
 
 BLEHourlyRecord ble_scanner_collect(uint32_t period_start, uint32_t period_end) {
-    portENTER_CRITICAL(&s_mux);
+    // Swap accumulators under lock — minimise time with lock held
+    std::map<String, DeviceObs> local_seen;
+    int local_max = 0;
+    {
+        std::lock_guard<std::mutex> lock(s_mutex);
+        std::swap(local_seen, s_seen);
+        local_max = s_max_concurrent;
+        s_max_concurrent = 0;
+    }
 
+    // Process outside the lock — heap allocation safe here
     BLEHourlyRecord rec;
     rec.period_start    = period_start;
     rec.period_end      = period_end;
-    rec.unique_devices = (int)s_seen.size();
+    rec.unique_devices  = (int)local_seen.size();
-    rec.max_concurrent = s_max_concurrent;
+    rec.max_concurrent  = local_max;
     rec.near_count = 0; rec.mid_count = 0; rec.far_count = 0;
 
-    for (auto& kv : s_seen) {
+    for (auto& kv : local_seen) {
-        float avg = kv.second.rssi_sum / (float)kv.second.count;
+        float avg_rssi = kv.second.rssi_sum / (float)kv.second.count;
-        if      (avg > RSSI_NEAR) rec.near_count++;
+        if (avg_rssi > RSSI_NEAR)      rec.near_count++;
-        else if (avg > RSSI_MID)  rec.mid_count++;
+        else if (avg_rssi > RSSI_MID)  rec.mid_count++;
         else                           rec.far_count++;
         rec.device_hashes.push_back(kv.first);
     }
-
-    s_seen.clear();
-    s_max_concurrent = 0;
-
-    portEXIT_CRITICAL(&s_mux);
     return rec;
 }

firmware/src/main.cpp

@@ -1,6 +1,7 @@
 // firmware/src/main.cpp
 #include <Arduino.h>
 #include <WiFi.h>
+#include <ArduinoOTA.h>
 #include "config.h"
 #include "provisioning.h"
 #include "camera.h"
@@ -139,8 +140,17 @@ void setup() {
         while (true) delay(1000);
     }
 
+    reporter_init();
+
     ble_scanner_start();
 
+    // OTA update support
+    ArduinoOTA.setHostname(g_cfg.device_id.c_str());
+    ArduinoOTA.onStart([]() { ble_scanner_pause(); });
+    ArduinoOTA.onEnd([]()   { ble_scanner_resume(); ESP.restart(); });
+    ArduinoOTA.onError([](ota_error_t e) { ble_scanner_resume(); });
+    ArduinoOTA.begin();
+
     s_cv_mutex = xSemaphoreCreateMutex();
 
     xTaskCreatePinnedToCore(task_camera,   "cam",  4096, nullptr, 2, nullptr, 1);
@@ -148,6 +158,7 @@ void setup() {
 }
 
 void loop() {
+    ArduinoOTA.handle();
     check_factory_reset();
 
     if (WiFi.status() != WL_CONNECTED) {

firmware/src/reporter.cpp

@@ -6,9 +6,15 @@
 #include <WiFi.h>
 #include <vector>
 #include <time.h>
+#include <freertos/semphr.h>
 
 static std::vector<CameraHourlyRecord> s_cam_buf;
 static std::vector<BLEHourlyRecord>    s_ble_buf;
+static SemaphoreHandle_t s_buf_mutex = nullptr;
+
+void reporter_init() {
+    s_buf_mutex = xSemaphoreCreateMutex();
+}
 
 // Returns current Unix timestamp (NTP-synced via configTime in main.cpp).
 static uint32_t now_ts() {
@@ -86,12 +92,19 @@ static void buf_add_ble(const BLEHourlyRecord& r) {
 }
 
 void reporter_submit_camera(const DeviceConfig& cfg, const CameraHourlyRecord& rec) {
-    if (WiFi.status() != WL_CONNECTED) { buf_add_cam(rec); return; }
+    if (WiFi.status() != WL_CONNECTED) {
+        xSemaphoreTake(s_buf_mutex, portMAX_DELAY);
+        buf_add_cam(rec);
+        xSemaphoreGive(s_buf_mutex);
+        return;
+    }
 
+    xSemaphoreTake(s_buf_mutex, portMAX_DELAY);
     std::vector<CameraHourlyRecord> batch;
     batch.insert(batch.end(), s_cam_buf.begin(), s_cam_buf.end());
     batch.push_back(rec);
     s_cam_buf.clear();
+    xSemaphoreGive(s_buf_mutex);
 
     // Cap to MAX_BUFFER: drop oldest to make room for newest
     if ((int)batch.size() > REPORTER_MAX_BUFFER) {
@@ -101,17 +114,26 @@ void reporter_submit_camera(const DeviceConfig& cfg, const CameraHourlyRecord& r
 
     String body = build_camera_batch(cfg, batch);
     if (!post_json(cfg, "/api/v1/camera/events/batch", body)) {
+        xSemaphoreTake(s_buf_mutex, portMAX_DELAY);
         s_cam_buf = batch; // re-buffer the whole capped batch
+        xSemaphoreGive(s_buf_mutex);
     }
 }
 
 void reporter_submit_ble(const DeviceConfig& cfg, const BLEHourlyRecord& rec) {
-    if (WiFi.status() != WL_CONNECTED) { buf_add_ble(rec); return; }
+    if (WiFi.status() != WL_CONNECTED) {
+        xSemaphoreTake(s_buf_mutex, portMAX_DELAY);
+        buf_add_ble(rec);
+        xSemaphoreGive(s_buf_mutex);
+        return;
+    }
 
+    xSemaphoreTake(s_buf_mutex, portMAX_DELAY);
     std::vector<BLEHourlyRecord> batch;
     batch.insert(batch.end(), s_ble_buf.begin(), s_ble_buf.end());
     batch.push_back(rec);
     s_ble_buf.clear();
+    xSemaphoreGive(s_buf_mutex);
 
     // Cap to MAX_BUFFER: drop oldest to make room for newest
     if ((int)batch.size() > REPORTER_MAX_BUFFER) {
@@ -121,7 +143,9 @@ void reporter_submit_ble(const DeviceConfig& cfg, const BLEHourlyRecord& rec) {
 
     String body = build_ble_batch(cfg, batch);
     if (!post_json(cfg, "/api/v1/events/batch", body)) {
+        xSemaphoreTake(s_buf_mutex, portMAX_DELAY);
         s_ble_buf = batch; // re-buffer the whole capped batch
+        xSemaphoreGive(s_buf_mutex);
     }
 }
 
@@ -137,12 +161,25 @@ void reporter_heartbeat(const DeviceConfig& cfg, uint32_t uptime_s, int wifi_rss
 }
 
 void reporter_flush(const DeviceConfig& cfg) {
-    if (!s_cam_buf.empty()) {
+    xSemaphoreTake(s_buf_mutex, portMAX_DELAY);
-        String body = build_camera_batch(cfg, s_cam_buf);
+    std::vector<CameraHourlyRecord> cam_snap = s_cam_buf;
-        if (post_json(cfg, "/api/v1/camera/events/batch", body)) s_cam_buf.clear();
+    std::vector<BLEHourlyRecord>    ble_snap = s_ble_buf;
+    xSemaphoreGive(s_buf_mutex);
+
+    if (!cam_snap.empty()) {
+        String body = build_camera_batch(cfg, cam_snap);
+        if (post_json(cfg, "/api/v1/camera/events/batch", body)) {
+            xSemaphoreTake(s_buf_mutex, portMAX_DELAY);
+            s_cam_buf.clear();
+            xSemaphoreGive(s_buf_mutex);
+        }
+    }
+    if (!ble_snap.empty()) {
+        String body = build_ble_batch(cfg, ble_snap);
+        if (post_json(cfg, "/api/v1/events/batch", body)) {
+            xSemaphoreTake(s_buf_mutex, portMAX_DELAY);
+            s_ble_buf.clear();
+            xSemaphoreGive(s_buf_mutex);
         }
-    if (!s_ble_buf.empty()) {
-        String body = build_ble_batch(cfg, s_ble_buf);
-        if (post_json(cfg, "/api/v1/events/batch", body)) s_ble_buf.clear();
     }
 }

firmware/src/reporter.h

@@ -14,6 +14,7 @@ struct CameraHourlyRecord {
 static const int    REPORTER_MAX_BUFFER = 24;
 static const char*  REPORTER_API_HOST   = "https://logs.research.bike";
 
+void reporter_init();
 void reporter_submit_camera(const DeviceConfig& cfg, const CameraHourlyRecord& rec);
 void reporter_submit_ble(const DeviceConfig& cfg, const BLEHourlyRecord& rec);
 void reporter_heartbeat(const DeviceConfig& cfg, uint32_t uptime_s, int wifi_rssi);

tools/flash_device.py

@@ -34,7 +34,7 @@ def build_nvs_csv(device_id, location_id, hmac_secret,
         f"device_id,data,string,{device_id}",
         f"location_id,data,string,{location_id}",
         f"hmac_secret,data,string,{hmac_secret}",
-        f"line_offset,data,u8,{line_offset}",
+        f"line_offset,data,u32,{line_offset}",
     ]
     if wifi_ssid is not None:
         rows.append(f"wifi_ssid,data,string,{wifi_ssid}")