sys/auto_init: add auto_init_wdt_{event, thread} modules

drivers/include/periph/wdt.h

@@ -157,9 +157,42 @@
  * Makefile add:
  *
  * ~~~~~~~~~~~~~~~~~~~~~~~~ {.mk}
- *    MODULE += periph_wdt_cb
+ *    USEMODULE += periph_wdt_cb
  * ~~~~~~~~~~~~~~~~~~~~~~~~
  *
+ * WDT Auto-Start
+ * ==============
+ *
+ * It is possible to enable the Watchdog in early boot, before application startup:
+ *
+ * ~~~~~~~~~~~~~~~~~~~~~~~~ {.mk}
+ *    USEMODULE += periph_wdt_auto_start
+ * ~~~~~~~~~~~~~~~~~~~~~~~~
+ *
+ * The watchdog will automatically be initialized with the parameters
+ * @ref CONFIG_PERIPH_WDT_WIN_MIN_MS and @ref CONFIG_PERIPH_WDT_WIN_MAX_MS
+ *
+ * It is also possible to automatically kick the watchdog.
+ * This is a very non-invasive way of using the watchdog, but it is also very
+ * weak as it can only detect situations where low-priority threads are
+ * starved from execution and may even trigger wrongly in situations where the
+ * system just experiences high load, but would otherwise have recovered on it's own.
+ *
+ * If you want to enable it anyway, select this module:
+ *
+ * ~~~~~~~~~~~~~~~~~~~~~~~~ {.mk}
+ *    USEMODULE += auto_init_wdt_thread
+ * ~~~~~~~~~~~~~~~~~~~~~~~~
+ *
+ * If you are using an event thread, you can also use the watchdog to ensure that events
+ * are processed in time.
+ * To do so, add
+ *
+ * ~~~~~~~~~~~~~~~~~~~~~~~~ {.mk}
+ *    USEMODULE += auto_init_wdt_event
+ * ~~~~~~~~~~~~~~~~~~~~~~~~
+ *
+ *
  * @{
  *
  * @file        wdt.h

makefiles/pseudomodules.inc.mk

@@ -589,6 +589,8 @@ NO_PSEUDOMODULES += auto_init_multimedia
 NO_PSEUDOMODULES += auto_init_security
 NO_PSEUDOMODULES += auto_init_usbus
 NO_PSEUDOMODULES += auto_init_screen
+NO_PSEUDOMODULES += auto_init_wdt_event
+NO_PSEUDOMODULES += auto_init_wdt_thread
 
 # Packages and drivers may also add modules to PSEUDOMODULES in their `Makefile.include`.
 

sys/Makefile.dep

@@ -24,6 +24,23 @@ ifneq (,$(filter auto_init_gnrc_netif,$(USEMODULE)))
   USEMODULE += gnrc_netif_init_devs
 endif
 
+ifneq (,$(filter auto_init_wdt_thread,$(USEMODULE)))
+  USEMODULE += periph_wdt_auto_start
+  USEMODULE += ztimer_msec
+
+  # we can only have either auto_init_wdt_event or auto_init_wdt_thread
+  ifneq (,$(filter auto_init_wdt_event,$(USEMODULE)))
+    $(error auto_init_wdt_event and auto_init_wdt_thread are mutually exclusive)
+  endif
+endif
+
+ifneq (,$(filter auto_init_wdt_event,$(USEMODULE)))
+  USEMODULE += event_periodic_callback
+  USEMODULE += event_thread
+  USEMODULE += periph_wdt_auto_start
+  USEMODULE += ztimer_msec
+endif
+
 ifneq (,$(filter auto_init_sock_dns,$(USEMODULE)))
   ifneq (,$(filter ipv4,$(USEMODULE)))
     USEMODULE += ipv4_addr

sys/auto_init/Makefile

@@ -30,4 +30,12 @@ ifneq (,$(filter auto_init_screen,$(USEMODULE)))
   DIRS += screen
 endif
 
+ifneq (,$(filter auto_init_wdt_event,$(USEMODULE)))
+  DIRS += wdt_event
+endif
+
+ifneq (,$(filter auto_init_wdt_thread,$(USEMODULE)))
+  DIRS += wdt_thread
+endif
+
 include $(RIOTBASE)/Makefile.base

sys/auto_init/include/auto_init_priorities.h

@@ -41,6 +41,12 @@ extern "C" {
  */
 #define AUTO_INIT_PRIO_MOD_XTIMER                       1030
 #endif
+#ifndef AUTO_INIT_PRIO_WDT_THREAD
+/**
+ * @brief   WDT priority
+ */
+#define AUTO_INIT_PRIO_WDT_THREAD                       1035
+#endif
 #ifndef AUTO_INIT_PRIO_MOD_RANDOM
 /**
  * @brief   RNG priority
@@ -71,6 +77,12 @@ extern "C" {
  */
 #define AUTO_INIT_PRIO_MOD_EVENT_THREAD                 1080
 #endif
+#ifndef AUTO_INIT_PRIO_WDT_EVENT
+/**
+ * @brief   WDT event priority
+ */
+#define AUTO_INIT_PRIO_WDT_EVENT                        1085
+#endif
 #ifndef AUTO_INIT_PRIO_MOD_SYS_BUS
 /**
  * @brief   sys bus priority

sys/auto_init/wdt_event/Makefile

@@ -0,0 +1,3 @@
+MODULE = auto_init_wdt_event
+
+include $(RIOTBASE)/Makefile.base

sys/auto_init/wdt_event/wdt.c

@@ -0,0 +1,47 @@
+/*
+ * Copyright (C) 2022 ML!PA Consulting GmbH
+ *
+ * This file is subject to the terms and conditions of the GNU Lesser
+ * General Public License v2.1. See the file LICENSE in the top level
+ * directory for more details.
+ */
+
+/**
+ * @ingroup     sys_auto_init
+ * @{
+ *
+ * @file        wdt.c
+ * @brief       Watchdog Event
+ *
+ * @author      Benjamin Valentin <benjamin.valentin@ml-pa.com>
+ *
+ * @}
+ */
+
+#include "auto_init.h"
+#include "auto_init_utils.h"
+#include "auto_init_priorities.h"
+
+#include "architecture.h"
+#include "event/periodic_callback.h"
+#include "event/thread.h"
+#include "periph/wdt.h"
+#include "ztimer.h"
+
+static void _wdt_event_cb(void *ctx)
+{
+    (void)ctx;
+    wdt_kick();
+}
+
+static void auto_init_wdt_event(void)
+{
+    static event_periodic_callback_t wdt_event;
+    unsigned sleep_ms = (CONFIG_PERIPH_WDT_WIN_MIN_MS + CONFIG_PERIPH_WDT_WIN_MAX_MS)
+                      / 2;
+
+    event_periodic_callback_init(&wdt_event, ZTIMER_MSEC, EVENT_PRIO_LOWEST, _wdt_event_cb, NULL);
+    event_periodic_callback_start(&wdt_event, sleep_ms);
+}
+
+AUTO_INIT(auto_init_wdt_event, AUTO_INIT_PRIO_WDT_EVENT);

sys/auto_init/wdt_thread/Makefile

@@ -0,0 +1,3 @@
+MODULE = auto_init_wdt_thread
+
+include $(RIOTBASE)/Makefile.base

sys/auto_init/wdt_thread/wdt.c

@@ -0,0 +1,58 @@
+/*
+ * Copyright (C) 2022 ML!PA Consulting GmbH
+ *
+ * This file is subject to the terms and conditions of the GNU Lesser
+ * General Public License v2.1. See the file LICENSE in the top level
+ * directory for more details.
+ */
+
+/**
+ * @ingroup     sys_auto_init
+ * @{
+ *
+ * @file        wdt.c
+ * @brief       Watchdog Thread
+ *
+ * @author      Benjamin Valentin <benjamin.valentin@ml-pa.com>
+ *
+ * @}
+ */
+
+#include "auto_init.h"
+#include "auto_init_utils.h"
+#include "auto_init_priorities.h"
+
+#include "architecture.h"
+#include "periph/wdt.h"
+#include "ztimer.h"
+
+#ifndef WDT_THREAD_STACKSIZE
+#if DEVELHELP
+#define WDT_THREAD_STACKSIZE    THREAD_STACKSIZE_SMALL
+#else
+#define WDT_THREAD_STACKSIZE    THREAD_STACKSIZE_TINY
+#endif
+#endif
+
+static char WORD_ALIGNED wdt_stack[WDT_THREAD_STACKSIZE];
+
+static void *_wdt_thread(void *ctx)
+{
+    (void)ctx;
+    unsigned sleep_ms = (CONFIG_PERIPH_WDT_WIN_MIN_MS + CONFIG_PERIPH_WDT_WIN_MAX_MS)
+                      / 2;
+    while (1) {
+        ztimer_sleep(ZTIMER_MSEC, sleep_ms);
+        wdt_kick();
+    }
+
+    return NULL;
+}
+
+static void auto_init_wdt_thread(void)
+{
+    thread_create(wdt_stack, sizeof(wdt_stack), THREAD_PRIORITY_MIN,
+                  THREAD_CREATE_STACKTEST, _wdt_thread, NULL, "watchdog");
+}
+
+AUTO_INIT(auto_init_wdt_thread, AUTO_INIT_PRIO_WDT_THREAD);