app: add Room Server (BBS) role

Add the MeshCore Room Server role to ZephCore — a store-and-forward shared message room. Clients log in with an admin or guest password and post messages; the server pushes each new post to all other logged-in clients (round-robin, per-client sync cursor, ACK + retry, 3-strike eviction). Ported from upstream MeshCore's simple_room_server, structured as a near-clone of RepeaterMesh so it reuses the proven ACL, region filtering, CLI, adverts and telemetry; the post buffer + push engine are the only net-new pieces: - RoomServerMesh: PostInfo ring (MAX_UNSYNCED_POSTS=32), addPost, pushPostToClient, getUnsyncedCount, processAck, onAckRecv, the loop() push driver; room login (onAnonDataRecv parses the sync_since cursor); posts/admin-CLI/keep-alive (onPeerDataRecv); ADV_TYPE_ROOM advert; ServerStats wire layout; disable_fwd=1. - main_room_server.cpp: event-loop entry (USB serial CLI, no BLE). - Kconfig: ZEPHCORE_ROLE_ROOM_SERVER + ZEPHCORE_MAX_UNSYNCED_POSTS. - CMakeLists role gating; boards/common/room_server.conf. Post frame, SHA-256 ACK and login-reply layouts match upstream for MeshCore app compatibility. Builds for gat562_30s (FLASH 30.95% / RAM 32.46%). Not yet hardware-tested.
2026-09-17 02:54:22 +00:00 · 2026-06-02 13:02:57 -05:00
parent 568d311ab0
commit bb6d9c60e1
7 changed files with 2806 additions and 4 deletions
@@ -0,0 +1,555 @@
+/*
+ * SPDX-License-Identifier: Apache-2.0
+ * ZephCore - Room Server (USB CLI, Event-Driven)
+ *
+ * This is the main entry point for the room server (shared BBS) role.
+ * Room servers use USB serial CLI for configuration (no BLE).
+ */
+
+#include <stdio.h>
+#include <string.h>
+#include <zephyr/kernel.h>
+#include <zephyr/sys/util.h>
+
+#include <zephyr/logging/log.h>
+LOG_MODULE_REGISTER(zephcore_room_main, CONFIG_ZEPHCORE_MAIN_LOG_LEVEL);
+
+#include <zephyr/device.h>
+#include <zephyr/devicetree.h>
+#include <zephyr/drivers/gpio.h>
+#include <zephyr/drivers/uart.h>
+#include <zephyr/sys/ring_buffer.h>
+#include <zephyr/drivers/hwinfo.h>
+#include <zephyr/sys/reboot.h>
+#include "oled_power.h"
+
+/* BLE controller assert handler — BT is compiled even for repeater (via zephcore_common.conf) */
+#if IS_ENABLED(CONFIG_BT_CTLR_ASSERT_HANDLER)
+extern "C" void bt_ctlr_assert_handle(char *file, uint32_t line)
+{
+	LOG_ERR("!!! BLE CONTROLLER ASSERT: %s:%u !!!", file ? file : "?", line);
+	k_sleep(K_MSEC(100));
+	sys_reboot(SYS_REBOOT_COLD);
+}
+#endif
+
+/* USB CDC ACM init + 1200-baud DFU + DTR callbacks (shared with companion) */
+#if !IS_ENABLED(CONFIG_CDC_ACM_SERIAL_INITIALIZE_AT_BOOT)
+#include <ZephyrUSBCDC.h>
+#endif
+
+#include <app/RepeaterDataStore.h>
+#include <app/RoomServerMesh.h>
+#include <adapters/clock/ZephyrRTCClock.h>
+#include <ZephyrSensorManager.h>
+
+/* UI subsystem (display, buttons, buzzer) */
+#include "ui_task.h"
+
+/* Radio + mesh includes (shared header selects LR1110 or SX126x) */
+#include <mesh/RadioIncludes.h>
+
+#if IS_ENABLED(CONFIG_ZEPHCORE_WIFI_OTA)
+#include "wifi_ota.h"
+#endif
+
+/* LED configuration */
+#if DT_NODE_HAS_PROP(DT_ALIAS(led0), gpios)
+#define LED0_NODE DT_ALIAS(led0)
+static const struct gpio_dt_spec led0 = GPIO_DT_SPEC_GET(LED0_NODE, gpios);
+#endif
+#if DT_NODE_HAS_PROP(DT_ALIAS(led1), gpios)
+#define LED1_NODE DT_ALIAS(led1)
+static const struct gpio_dt_spec led1 = GPIO_DT_SPEC_GET(LED1_NODE, gpios);
+#endif
+
+/* USB CLI configuration */
+#define USB_RING_BUF_SIZE 512
+#define CLI_LINE_BUF_SIZE 256
+
+/*
+ * Event-driven mesh loop - replaces 50ms polling with true event signaling.
+ * Events are signaled from ISR/callbacks, mesh loop wakes immediately.
+ */
+#define MESH_EVENT_LORA_RX       BIT(0)  /* LoRa packet received */
+#define MESH_EVENT_LORA_TX_DONE  BIT(1)  /* LoRa TX complete */
+#define MESH_EVENT_CLI_RX        BIT(2)  /* CLI command received */
+#define MESH_EVENT_HOUSEKEEPING  BIT(3)  /* Periodic housekeeping (noise floor, etc.) */
+#define MESH_EVENT_GPS_ACTION    BIT(4)  /* GPS state change (must run on main thread!) */
+#define MESH_EVENT_TX_DRAIN      BIT(5)  /* Outbound packet delay expired, run checkSend */
+#define MESH_EVENT_ALL           (MESH_EVENT_LORA_RX | MESH_EVENT_LORA_TX_DONE | MESH_EVENT_CLI_RX | MESH_EVENT_HOUSEKEEPING | MESH_EVENT_GPS_ACTION | MESH_EVENT_TX_DRAIN)
+
+/* Housekeeping interval - infrequent to preserve power savings */
+#define HOUSEKEEPING_INTERVAL_MS CONFIG_ZEPHCORE_HOUSEKEEPING_INTERVAL_MS
+
+/* Event object for mesh loop */
+static struct k_event mesh_events;
+
+/* USB CDC state */
+static const struct device *usb_dev;
+static uint8_t usb_ring_buf_data[USB_RING_BUF_SIZE];
+static struct ring_buf usb_ring_buf;
+static char cli_line_buf[CLI_LINE_BUF_SIZE];
+static char cli_reply_buf[256];
+static uint16_t cli_line_idx;
+
+/* Work items for event-driven processing */
+static void cli_rx_work_fn(struct k_work *work);
+static void housekeeping_timer_fn(struct k_timer *timer);
+static void tx_drain_work_fn(struct k_work *work);
+static void initial_advert_work_fn(struct k_work *work);
+K_WORK_DEFINE(cli_rx_work, cli_rx_work_fn);
+K_WORK_DELAYABLE_DEFINE(tx_drain_work, tx_drain_work_fn);
+K_WORK_DELAYABLE_DEFINE(initial_advert_work, initial_advert_work_fn);
+
+/* Housekeeping timer for periodic tasks (noise floor calibration, etc.) */
+K_TIMER_DEFINE(housekeeping_timer, housekeeping_timer_fn, NULL);
+
+/* Forward declarations */
+#ifdef ZEPHCORE_LORA
+static RoomServerMesh *room_mesh_ptr;
+#endif
+
+/* Print string to USB serial */
+static void cli_print(const char *str)
+{
+	if (!usb_dev) return;
+	while (*str) {
+		uart_poll_out(usb_dev, *str++);
+	}
+}
+
+/* USB CDC UART interrupt callback */
+static void cli_uart_isr(const struct device *dev, void *user_data)
+{
+	ARG_UNUSED(user_data);
+
+	while (uart_irq_update(dev) && uart_irq_is_pending(dev)) {
+		if (uart_irq_rx_ready(dev)) {
+			uint8_t buf[64];
+			int recv_len = uart_fifo_read(dev, buf, sizeof(buf));
+			if (recv_len > 0) {
+				ring_buf_put(&usb_ring_buf, buf, recv_len);
+				k_work_submit(&cli_rx_work);
+			}
+		}
+	}
+}
+
+/* CLI RX work - processes line-based CLI commands
+ * Matches Arduino behavior: echo each char, then "  -> reply" on enter
+ */
+static void cli_rx_work_fn(struct k_work *work)
+{
+	ARG_UNUSED(work);
+	uint8_t byte;
+
+	while (ring_buf_get(&usb_ring_buf, &byte, 1) == 1) {
+		/* Process command on \r OR \n (support echo from Linux) */
+		if (byte == '\r' || byte == '\n') {
+			if (cli_line_idx > 0) {
+				cli_line_buf[cli_line_idx] = '\0';
+
+				/* Debug: log received command */
+				LOG_INF("CLI cmd len=%d: %.40s%s", cli_line_idx,
+					cli_line_buf, cli_line_idx > 40 ? "..." : "");
+
+				/* Process CLI command */
+#ifdef ZEPHCORE_LORA
+				if (room_mesh_ptr) {
+					cli_reply_buf[0] = '\0';
+					room_mesh_ptr->handleCommand(0, cli_line_buf, cli_reply_buf);
+					if (cli_reply_buf[0] != '\0') {
+						/* Arduino format: newline, then "  -> reply" */
+						cli_print("\r\n  -> ");
+						cli_print(cli_reply_buf);
+					}
+				}
+#endif
+				cli_line_idx = 0;
+			}
+			/* New line for next command */
+			cli_print("\r\n");
+		} else if (byte == 0x7F || byte == 0x08) {
+			/* Backspace - echo backspace sequence */
+			if (cli_line_idx > 0) {
+				cli_line_idx--;
+				if (usb_dev) {
+					uart_poll_out(usb_dev, '\b');
+					uart_poll_out(usb_dev, ' ');
+					uart_poll_out(usb_dev, '\b');
+				}
+			}
+		} else if (cli_line_idx < sizeof(cli_line_buf) - 1) {
+			/* Echo character back (like Arduino) */
+			if (usb_dev) {
+				uart_poll_out(usb_dev, byte);
+			}
+			cli_line_buf[cli_line_idx++] = (char)byte;
+		}
+	}
+}
+
+/* Housekeeping timer callback - signals event to wake mesh loop periodically */
+static void housekeeping_timer_fn(struct k_timer *timer)
+{
+	ARG_UNUSED(timer);
+	k_event_post(&mesh_events, MESH_EVENT_HOUSEKEEPING);
+}
+
+#ifdef ZEPHCORE_LORA
+/* LoRa RX callback - called from ISR context when packet received */
+static void lora_rx_callback(void *user_data)
+{
+	ARG_UNUSED(user_data);
+	k_event_post(&mesh_events, MESH_EVENT_LORA_RX);
+}
+
+/* LoRa TX complete callback */
+static void lora_tx_done_callback(void *user_data)
+{
+	ARG_UNUSED(user_data);
+	k_event_post(&mesh_events, MESH_EVENT_LORA_TX_DONE);
+}
+
+/* TX drain — Dispatcher queued a packet with a delay.
+ * Schedule a precise wake so checkSend runs when the delay expires. */
+static void tx_drain_work_fn(struct k_work *work)
+{
+	ARG_UNUSED(work);
+	k_event_post(&mesh_events, MESH_EVENT_TX_DRAIN);
+}
+
+/* Deferred initial advertisement — gives GPS time to get a fix at boot */
+static void initial_advert_work_fn(struct k_work *work)
+{
+	ARG_UNUSED(work);
+#ifdef ZEPHCORE_LORA
+	if (room_mesh_ptr) {
+		LOG_INF("Sending deferred initial advertisement");
+		room_mesh_ptr->sendSelfAdvertisement(500, false);
+	}
+#endif
+}
+
+static void tx_queued_callback(uint32_t delay_ms, void *user_data)
+{
+	ARG_UNUSED(user_data);
+	k_work_reschedule(&tx_drain_work, K_MSEC(delay_ms));
+}
+#endif
+
+/* Global instances */
+static mesh::ZephyrRTCClock rtc_clock;
+
+/* GPS event callback - called when GPS work handlers need the main thread
+ * to process a state transition (wake from standby, fix done, timeout).
+ * Runs from system work queue context — just posts an event, no blocking. */
+static void gps_event_callback(void)
+{
+	k_event_post(&mesh_events, MESH_EVENT_GPS_ACTION);
+}
+
+static RepeaterDataStore data_store;
+
+/* GPS fix callback - syncs RTC from GPS time.
+ * Repeaters do NOT update prefs lat/lon from GPS — prefs coordinates are the
+ * user's manually-set position used for adverts.  Precise GPS position is
+ * served only via telemetry requests (gps_get_last_known_position). */
+static void gps_fix_callback(double lat, double lon, int64_t utc_time)
+{
+	if (utc_time > 0) {
+		LOG_INF("GPS fix: RTC sync time=%lld", utc_time);
+		rtc_clock.setCurrentTime((uint32_t)utc_time);
+	}
+
+	int lat_deg = (int)lat;
+	int lon_deg = (int)lon;
+	int lat_frac = (int)((lat - lat_deg) * 1000000);
+	int lon_frac = (int)((lon - lon_deg) * 1000000);
+	if (lat_frac < 0) lat_frac = -lat_frac;
+	if (lon_frac < 0) lon_frac = -lon_frac;
+	LOG_INF("GPS fix: lat=%d.%06d lon=%d.%06d (telemetry only)",
+		lat_deg, lat_frac, lon_deg, lon_frac);
+}
+
+#ifdef ZEPHCORE_LORA
+static mesh::ZephyrBoard zephyr_board;
+
+static uint16_t get_battery_mv(void)
+{
+	return zephyr_board.getBattMilliVolts();
+}
+
+/* Radio is constructed with no prefs pointer; main() binds it to
+ * room_mesh._prefs via setPrefs() before room_mesh.begin(). */
+
+#if IS_ENABLED(CONFIG_ZEPHCORE_RADIO_LR1110)
+/* LR1110 via Zephyr LoRa driver */
+static const struct device *const lora_dev = DEVICE_DT_GET(DT_ALIAS(lora0));
+static mesh::LR1110Radio lora_radio(lora_dev, zephyr_board);
+#elif IS_ENABLED(CONFIG_ZEPHCORE_RADIO_SX127X)
+/* SX127x via Zephyr loramac-node driver */
+static const struct device *const lora_dev = DEVICE_DT_GET(DT_ALIAS(lora0));
+static mesh::SX127xRadio lora_radio(lora_dev, zephyr_board);
+#else
+/* SX126x via Zephyr LoRa driver */
+static const struct device *const lora_dev = DEVICE_DT_GET(DT_ALIAS(lora0));
+static mesh::SX126xRadio lora_radio(lora_dev, zephyr_board);
+#endif
+
+static mesh::ZephyrMillisecondClock ms_clock;
+static mesh::ZephyrRNG zephyr_rng;
+static mesh::SimpleMeshTables mesh_tables;
+
+/* RoomServerMesh requires: board, radio, ms_clock, rng, rtc, tables */
+static RoomServerMesh room_mesh(zephyr_board, lora_radio, ms_clock, zephyr_rng, rtc_clock, mesh_tables);
+#endif
+
+/* Repeater event loop */
+static void room_event_loop(void)
+{
+	LOG_INF("starting event-driven loop");
+
+	/* Print startup banner (no prompt - Arduino style) */
+	cli_print("\r\n=== ZephCore Room Server ===\r\n");
+
+	/* Start housekeeping timer for periodic maintenance tasks */
+	k_timer_start(&housekeeping_timer, K_MSEC(HOUSEKEEPING_INTERVAL_MS),
+		      K_MSEC(HOUSEKEEPING_INTERVAL_MS));
+
+	for (;;) {
+		/* Wait for any mesh event - blocks until signaled */
+		uint32_t events = k_event_wait(&mesh_events, MESH_EVENT_ALL, false, K_FOREVER);
+		k_event_clear(&mesh_events, events);
+
+		/* GPS state transitions must run on main thread (GNSS driver
+		 * modem_chat blocks on system work queue semaphore). */
+		if (events & MESH_EVENT_GPS_ACTION) {
+			gps_process_event();
+		}
+
+#ifdef ZEPHCORE_LORA
+		/* Packet processing — only on radio/CLI/TX events */
+		if (room_mesh_ptr &&
+		    (events & (MESH_EVENT_LORA_RX | MESH_EVENT_LORA_TX_DONE |
+			       MESH_EVENT_CLI_RX | MESH_EVENT_TX_DRAIN))) {
+			room_mesh_ptr->loop();
+		}
+#endif
+
+		/* Periodic housekeeping — maintenance + display refresh */
+		if (events & MESH_EVENT_HOUSEKEEPING) {
+#ifdef ZEPHCORE_LORA
+			/* Radio maintenance: noise floor calibration, AGC reset,
+			 * RX watchdog.  Separated from loop() so these never run
+			 * on packet-driven events. */
+			if (room_mesh_ptr) {
+				room_mesh_ptr->maintenanceLoop();
+				/* Also drive loop() so time-based actions (advert
+				 * timers, tempradio set/revert, contacts flush,
+				 * uplink status) still fire when no LoRa/CLI
+				 * traffic wakes the event loop. */
+				room_mesh_ptr->loop();
+			}
+#endif
+
+			ui_set_clock(rtc_clock.getCurrentTime());
+
+#ifdef ZEPHCORE_LORA
+			/* Refresh radio params (noise floor changes from calibration) */
+			if (room_mesh_ptr) {
+				NodePrefs *p = room_mesh_ptr->getNodePrefs();
+				ui_set_radio_params(
+					(uint32_t)(p->freq * 1000000.0f + 0.5f),
+					p->sf,
+					(uint16_t)(p->bw * 10.0f + 0.5f),
+					p->cr,
+					p->tx_power_dbm,
+					lora_radio.getNoiseFloor());
+			}
+
+			/* Battery is now refreshed lazily from ui_pages_render() with
+			 * a 30 s freshness guard — no periodic ADC fire here. */
+#endif
+		}
+	}
+}
+
+int main(void)
+{
+#ifdef ZEPHCORE_LORA
+	/* Clear any stale bootloader magic from previous sessions.
+	 * Prevents nRF52 boards from re-entering bootloader after reboot. */
+	zephyr_board.clearBootloaderMagic();
+#endif
+
+	/* USB CDC init up front so the host can enumerate, then wait for the
+	 * host to open the port (DTR asserted) — event-driven via the usbd
+	 * message callback.  Unplugged → 2 s timeout, no banner; attached →
+	 * banner reaches the user the moment the port opens. */
+#if !IS_ENABLED(CONFIG_CDC_ACM_SERIAL_INITIALIZE_AT_BOOT) && DT_HAS_COMPAT_STATUS_OKAY(zephyr_cdc_acm_uart)
+	zephcore_usbd_init();
+#endif
+#if DT_HAS_COMPAT_STATUS_OKAY(zephyr_cdc_acm_uart)
+	zephcore_usbd_wait_dtr(2000);
+#endif
+	LOG_INF("=== ZephCore Room Server starting ===");
+
+#if IS_ENABLED(CONFIG_ZEPHCORE_WIFI_OTA)
+	/* Confirm MCUboot image early — if we just booted after OTA,
+	 * this marks the image as good so MCUboot keeps it. */
+	wifi_ota_confirm_image();
+#endif
+
+	/* Configure LEDs */
+#if DT_NODE_HAS_PROP(DT_ALIAS(led0), gpios)
+	if (gpio_is_ready_dt(&led0)) {
+		gpio_pin_configure_dt(&led0, GPIO_OUTPUT_INACTIVE);
+	}
+#endif
+#if DT_NODE_HAS_PROP(DT_ALIAS(led1), gpios)
+	if (gpio_is_ready_dt(&led1)) {
+		gpio_pin_configure_dt(&led1, GPIO_OUTPUT_INACTIVE);
+	}
+#endif
+
+	/* Initialize repeater data store */
+	if (!data_store.begin()) {
+		LOG_ERR("RepeaterDataStore init failed");
+	}
+
+	/* Initialize sensor manager */
+	sensor_manager_init();
+
+	/* Set GPS to repeater mode: power off now, wake every 48h for time sync only.
+	 * This prevents GPS from draining power on boards that have it (e.g., Wio Tracker). */
+	if (gps_is_available()) {
+		gps_set_fix_callback(gps_fix_callback);
+		gps_set_event_callback(gps_event_callback);
+		gps_set_repeater_mode(true);
+	}
+
+	/* Initialize UI (display + buttons).  Shows splash screen, then auto-
+	 * transitions to STATUS page.  Display sleeps after auto-off timeout;
+	 * user button is the only wake source for repeater. */
+	ui_init();
+#if !IS_ENABLED(CONFIG_ZEPHCORE_UI_DISPLAY)
+	oled_sleep();
+#endif
+
+	/* Log environment sensor availability */
+	if (env_sensors_available()) {
+		LOG_INF("Environment sensors available");
+	}
+
+#ifdef ZEPHCORE_LORA
+	room_mesh_ptr = &room_mesh;
+
+	/* Initialize mesh event object BEFORE begin() — radio callbacks post events */
+	k_event_init(&mesh_events);
+
+	/* Set LoRa callbacks for event-driven packet processing */
+	lora_radio.setRxCallback(lora_rx_callback, nullptr);
+	lora_radio.setTxDoneCallback(lora_tx_done_callback, nullptr);
+	room_mesh.setTxQueuedCallback(tx_queued_callback, nullptr);
+
+	/* Load or generate identity BEFORE begin(). First-boot keygen runs
+	 * the layered entropy mixer + Ed25519 derive + reserved-prefix
+	 * guard inside ZephyrRNG::generateFirstBootIdentity. */
+	mesh::LocalIdentity self_identity;
+	if (!data_store.loadIdentity(self_identity)) {
+		LOG_INF("No identity found, generating new keypair...");
+		mesh::ZephyrRNG::generateFirstBootIdentity(self_identity);
+		data_store.saveIdentity(self_identity);
+		LOG_INF("New identity saved");
+	}
+	room_mesh.self_id = self_identity;
+
+	/* Log repeater ID (first 8 bytes of public key) */
+	LOG_INF("Room ID: %02x%02x%02x%02x%02x%02x%02x%02x...",
+		self_identity.pub_key[0], self_identity.pub_key[1],
+		self_identity.pub_key[2], self_identity.pub_key[3],
+		self_identity.pub_key[4], self_identity.pub_key[5],
+		self_identity.pub_key[6], self_identity.pub_key[7]);
+
+	/* Load persisted prefs and bind the radio to _prefs BEFORE begin() — the
+	 * radio reads freq/bw/sf/cr through this pointer during Mesh::begin() →
+	 * Dispatcher::begin() → Radio::begin().  Without this, the radio would
+	 * configure on NodePrefs defaults (869.618 MHz) regardless of saved
+	 * settings: CLI readback looked correct but the hardware stayed on EU.
+	 * Mirrors the temp_prefs pattern in main_companion.cpp. */
+	data_store.loadPrefs(*room_mesh.getNodePrefs());
+	lora_radio.setPrefs(room_mesh.getNodePrefs());
+
+	/* Start mesh with data store - loads ACL, regions */
+	room_mesh.begin(&data_store);
+
+	/* Generate default node name from hardware device ID if not set */
+	NodePrefs* prefs = room_mesh.getNodePrefs();
+	if (strlen(prefs->node_name) == 0 || strcmp(prefs->node_name, "Room") == 0) {
+		uint8_t dev_id[8];
+		ssize_t id_len = hwinfo_get_device_id(dev_id, sizeof(dev_id));
+		if (id_len >= 4) {
+			snprintf(prefs->node_name, sizeof(prefs->node_name),
+				 "Room-%02X%02X%02X%02X", dev_id[0], dev_id[1], dev_id[2], dev_id[3]);
+		}
+	}
+
+	/* Apply RX boost and duty cycle from prefs */
+	lora_radio.setRxBoost(prefs->rx_boost != 0);
+	lora_radio.enableRxDutyCycle(prefs->rx_duty_cycle != 0);
+
+	/* Feed initial UI state from loaded prefs */
+	ui_set_node_name(prefs->node_name);
+	ui_set_radio_params(
+		(uint32_t)(prefs->freq * 1000000.0f + 0.5f),  /* MHz → Hz */
+		prefs->sf,
+		(uint16_t)(prefs->bw * 10.0f + 0.5f),         /* kHz → 0.1 kHz */
+		prefs->cr,
+		prefs->tx_power_dbm,
+		lora_radio.getNoiseFloor());
+	ui_set_battery_provider(get_battery_mv);
+	ui_set_battery(zephyr_board.getBattMilliVolts(), 0);
+	ui_set_gps_available(gps_is_available());
+
+	/* Defer initial advertisement by 10s — gives GPS time for a quick fix.
+	 * Advert payload (including coords) is built when the work fires. */
+	LOG_INF("Initial advertisement scheduled in 10s");
+	k_work_schedule(&initial_advert_work, K_SECONDS(10));
+#endif
+
+	/* USB CDC was initialized earlier (right after clearBootloaderMagic).
+	 * Just acquire the device handle for the CLI's UART IRQ binding below. */
+#if DT_HAS_COMPAT_STATUS_OKAY(zephyr_cdc_acm_uart)
+	usb_dev = DEVICE_DT_GET_ONE(zephyr_cdc_acm_uart);
+#else
+	/* No CDC ACM (e.g. ESP32 usb_serial) — use chosen console UART */
+	usb_dev = DEVICE_DT_GET(DT_CHOSEN(zephyr_console));
+#endif
+	if (device_is_ready(usb_dev)) {
+		LOG_INF("USB CDC device ready: %s", usb_dev->name);
+		ring_buf_init(&usb_ring_buf, sizeof(usb_ring_buf_data), usb_ring_buf_data);
+
+		/* Set up UART interrupt callback */
+		uart_irq_callback_set(usb_dev, cli_uart_isr);
+		uart_irq_rx_enable(usb_dev);
+	} else {
+		LOG_ERR("USB CDC device not ready");
+		usb_dev = NULL;
+	}
+
+	/*
+	 * Event-driven architecture: main thread runs repeater event loop.
+	 * No BLE - all configuration via USB serial CLI.
+	 */
+#ifdef ZEPHCORE_LORA
+	room_event_loop();  /* Never returns */
+#else
+	for (;;) {
+		k_sleep(K_FOREVER);
+	}
+#endif
+
+	return 0;
+}