nrf52: add watchdog (#8485)

* nrf52: add watchdog

Main thread only for now.

* bump framework-arduinoadafruitnrf52 to pick up new wdt support

* clang-format the new parts of main-nrf52.cpp

---------

Co-authored-by: Ben Meadors <[email protected]>

Author: SebKuzminsky

arch/nrf52/nrf52.ini

@@ -7,7 +7,7 @@ extends = arduino_base
 platform_packages =
   ; our custom Git version until they merge our PR
   # TODO renovate
-  platformio/framework-arduinoadafruitnrf52 @ https://github.com/meshtastic/Adafruit_nRF52_Arduino#e13f5820002a4fb2a5e6754b42ace185277e5adf
+  platformio/framework-arduinoadafruitnrf52 @ https://github.com/meshtastic/Adafruit_nRF52_Arduino#c770c8a16a351b55b86e347a3d9d7b74ad0bbf39
   ; Don't renovate toolchain-gccarmnoneeabi
   platformio/toolchain-gccarmnoneeabi@~1.90301.0
 

src/platform/nrf52/main-nrf52.cpp

@@ -4,6 +4,13 @@
 #include <InternalFileSystem.h>
 #include <SPI.h>
 #include <Wire.h>
+
+#define NRFX_WDT_ENABLED 1
+#define NRFX_WDT0_ENABLED 1
+#define NRFX_WDT_CONFIG_NO_IRQ 1
+#include <nrfx_wdt.c>
+#include <nrfx_wdt.h>
+
 #include <assert.h>
 #include <ble_gap.h>
 #include <memory.h>
@@ -19,6 +26,9 @@
 #include "BQ25713.h"
 #endif
 
+static nrfx_wdt_t nrfx_wdt = NRFX_WDT_INSTANCE(0);
+static nrfx_wdt_channel_id nrfx_wdt_channel_id_nrf52_main;
+
 static inline void debugger_break(void)
 {
     __asm volatile("bkpt #0x01\n\t"
@@ -202,6 +212,15 @@ void checkSDEvents()
 
 void nrf52Loop()
 {
+    {
+        static bool watchdog_running = false;
+        if (!watchdog_running) {
+            nrfx_wdt_enable(&nrfx_wdt);
+            watchdog_running = true;
+        }
+    }
+    nrfx_wdt_channel_feed(&nrfx_wdt, nrfx_wdt_channel_id_nrf52_main);
+
     checkSDEvents();
     reportLittleFSCorruptionOnce();
 }
@@ -269,6 +288,20 @@ void nrf52Setup()
     LOG_DEBUG("Set random seed %u", seed.seed32);
     randomSeed(seed.seed32);
     nRFCrypto.end();
+
+    // Set up nrfx watchdog. Do not enable the watchdog yet (we do that
+    // the first time through the main loop), so that other threads can
+    // allocate their own wdt channel to protect themselves from hangs.
+    nrfx_wdt_config_t wdt0_config = {
+        .behaviour = NRF_WDT_BEHAVIOUR_RUN_SLEEP, .reload_value = 2000,
+        // Note: Not using wdt interrupts.
+        // .interrupt_priority = NRFX_WDT_DEFAULT_CONFIG_IRQ_PRIORITY
+    };
+    nrfx_err_t r = nrfx_wdt_init(&nrfx_wdt, &wdt0_config,
+                                 nullptr // Watchdog event handler, not used, we just reset.
+    );
+
+    r = nrfx_wdt_channel_alloc(&nrfx_wdt, &nrfx_wdt_channel_id_nrf52_main);
 }
 
 void cpuDeepSleep(uint32_t msecToWake)