added watchdog

platform/plat_init.c

@@ -15,6 +15,7 @@
 #include "debug_uart.h"
 #include "irq_dispatcher.h"
 #include "timebase.h"
+#include "watchdog.h"
 
 void plat_init(void)
 {
@@ -39,4 +40,6 @@ void plat_init(void)
     settings_load(); // XXX maybe this should be moved to the main task
 
     comm_init();
+
+    wd_init();
 }

platform/watchdog.c

@@ -0,0 +1,57 @@
+//
+// Created by MightyPork on 2018/02/27.
+//
+
+#include "platform.h"
+#include "watchdog.h"
+
+static volatile uint16_t suspend_depth = 0;
+static volatile bool restart_pending = false;
+
+void wd_init(void)
+{
+    dbg("IWDG init, time 2s");
+
+    LL_IWDG_Enable(IWDG);
+    LL_IWDG_EnableWriteAccess(IWDG);
+    LL_IWDG_SetPrescaler(IWDG, LL_IWDG_PRESCALER_32); // 0.8 ms
+    LL_IWDG_SetReloadCounter(IWDG, 2500); // 2s.  max 4095
+    while (!LL_IWDG_IsReady(IWDG));
+
+    // reload
+    LL_IWDG_ReloadCounter(IWDG);
+}
+
+void wd_suspend(void)
+{
+    vPortEnterCritical();
+    if (suspend_depth < 0xFFFF) {
+        suspend_depth++;
+    }
+    vPortExitCritical();
+}
+
+void wd_resume(void)
+{
+    vPortEnterCritical();
+    if (suspend_depth > 0) {
+        suspend_depth--;
+
+        if (suspend_depth == 0 && restart_pending) {
+            restart_pending = false;
+            LL_IWDG_ReloadCounter(IWDG);
+        }
+    }
+    vPortExitCritical();
+}
+
+void wd_restart(void)
+{
+    vPortEnterCritical();
+    if (suspend_depth == 0) {
+        LL_IWDG_ReloadCounter(IWDG);
+    } else {
+        restart_pending = true;
+    }
+    vPortExitCritical();
+}

platform/watchdog.h

@@ -0,0 +1,32 @@
+//
+// Created by MightyPork on 2018/02/27.
+//
+
+#ifndef GEX_F072_WATCHDOG_H
+#define GEX_F072_WATCHDOG_H
+
+/**
+ * Initialize the application watchdog
+ */
+void wd_init(void);
+
+/**
+ * Suspend watchdog restarts until resumed
+ * (used in other tasks to prevent the main task clearing the wd if the other task is locked up)
+ *
+ * The suspend/resume calls can be stacked.
+ */
+void wd_suspend(void);
+
+/**
+ * Resume restarts
+ */
+void wd_resume(void);
+
+/**
+ * Restart the wd. If restarts are suspended, postpone the restart until resumed
+ * and then restart immediately.
+ */
+void wd_restart(void);
+
+#endif //GEX_F072_WATCHDOG_H