HAL_ChibiOS: implement scheduler->expect_delay_ms()

# Conflicts:
#	libraries/AP_HAL_ChibiOS/HAL_ChibiOS_Class.cpp
#	libraries/AP_HAL_ChibiOS/Scheduler.h

libraries/AP_HAL_ChibiOS/HAL_ChibiOS_Class.cpp

@@ -190,8 +190,7 @@ static THD_FUNCTION(main_loop,arg)
     chThdSetPriority(APM_MAIN_PRIORITY);
 
     // setup watchdog to reset if main loop stops
-    bool using_watchdog = AP_BoardConfig::watchdog_enabled();
-    if (using_watchdog) {
+    if (AP_BoardConfig::watchdog_enabled()) {
         stm32_watchdog_init();
     }
 
@@ -209,9 +208,7 @@ static THD_FUNCTION(main_loop,arg)
         if (!schedulerInstance.check_called_boost()) {
             hal.scheduler->delay_microseconds(250);
         }
-        if (using_watchdog) {
-            stm32_watchdog_pat();
-        }
+        stm32_watchdog_pat();
 
 #if 0
         // simple method to test watchdog functionality

libraries/AP_HAL_ChibiOS/Scheduler.cpp

@@ -33,6 +33,7 @@
 #include <AP_Scheduler/AP_Scheduler.h>
 #include <AP_BoardConfig/AP_BoardConfig.h>
 #include "hwdef/common/stm32_util.h"
+#include "hwdef/common/watchdog.h"
 #include "shared_dma.h"
 #include "sdcard.h"
 
@@ -289,6 +290,13 @@ void Scheduler::_timer_thread(void *arg)
 
         // process any pending RC output requests
         hal.rcout->timer_tick();
+
+        if (sched->expect_delay_start != 0) {
+            uint32_t now = AP_HAL::millis();
+            if (now - sched->expect_delay_start <= sched->expect_delay_length) {
+                stm32_watchdog_pat();
+            }
+        }
     }
 }
 #if HAL_WITH_UAVCAN
@@ -473,4 +481,24 @@ bool Scheduler::thread_create(AP_HAL::MemberProc proc, const char *name, uint32_
     return true;
 }
 
+/*
+  inform the scheduler that we are calling an operation from the
+  main thread that may take an extended amount of time. This can
+  be used to prevent watchdog reset during expected long delays
+  A value of zero cancels the previous expected delay
+*/
+void Scheduler::expect_delay_ms(uint32_t ms)
+{
+    if (!in_main_thread()) {
+        // only for main thread
+        return;
+    }
+    if (ms == 0) {
+        expect_delay_start = 0;
+    } else {
+        expect_delay_start = AP_HAL::millis();
+        expect_delay_length = ms;
+    }
+}
+
 #endif // CH_CFG_USE_DYNAMIC

libraries/AP_HAL_ChibiOS/Scheduler.h

@@ -80,6 +80,14 @@ public:
 
     bool     check_called_boost(void);
 
+    /*
+      inform the scheduler that we are calling an operation from the
+      main thread that may take an extended amount of time. This can
+      be used to prevent watchdog reset during expected long delays
+      A value of zero cancels the previous expected delay
+     */
+    void     expect_delay_ms(uint32_t ms) override;
+    
     /*
       disable interrupts and return a context that can be used to
       restore the interrupt state. This can be used to protect
@@ -103,7 +111,8 @@ private:
     AP_HAL::Proc _failsafe;
     bool _called_boost;
     bool _priority_boosted;
-    
+    uint32_t expect_delay_start;
+    uint32_t expect_delay_length;
 
     AP_HAL::MemberProc _timer_proc[CHIBIOS_SCHEDULER_MAX_TIMER_PROCS];
     uint8_t _num_timer_procs;

libraries/AP_HAL_ChibiOS/hwdef/common/board.c

@@ -67,6 +67,9 @@ void __late_init(void) {
   halInit();
   chSysInit();
   stm32_watchdog_save_reason();
+#ifndef HAL_BOOTLOADER_BUILD
+  stm32_watchdog_clear_reason();
+#endif
 #if CH_CFG_USE_HEAP == TRUE
   malloc_init();
 #endif

libraries/AP_HAL_ChibiOS/hwdef/common/watchdog.c

@@ -51,6 +51,9 @@ typedef struct
 
 #define IWDGD (*(IWDG_Regs *)(IWDG_BASE))
 
+static bool was_watchdog_reset;
+static bool watchdog_enabled;
+
 /*
   setup the watchdog
  */
@@ -61,6 +64,7 @@ void stm32_watchdog_init(void)
     IWDGD.PR = 8;
     IWDGD.RLR = 0xFFF;
     IWDGD.KR = 0xCCCC;
+    watchdog_enabled = true;
 }
 
 /*
@@ -69,11 +73,11 @@ void stm32_watchdog_init(void)
  */
 void stm32_watchdog_pat(void)
 {
-    IWDGD.KR = 0xAAAA;
+    if (watchdog_enabled) {
+        IWDGD.KR = 0xAAAA;
+    }
 }
 
-static bool was_watchdog_reset;
-
 /*
   save reason code for reset
  */
@@ -82,6 +86,13 @@ void stm32_watchdog_save_reason(void)
     if (WDG_RESET_STATUS & WDG_RESET_IS_IWDG) {
         was_watchdog_reset = true;
     }
+}
+
+/*
+  clear reason code for reset
+ */
+void stm32_watchdog_clear_reason(void)
+{
     WDG_RESET_STATUS = WDG_RESET_CLEAR;
 }
 

libraries/AP_HAL_ChibiOS/hwdef/common/watchdog.h

@@ -23,6 +23,11 @@ bool stm32_was_watchdog_reset(void);
   save the reset reason code
  */
 void stm32_watchdog_save_reason(void);
+
+/*
+  clear reset reason code
+ */
+void stm32_watchdog_clear_reason(void);
     
 #ifdef __cplusplus
 }