From a5309b3afa30287797d81ed00e5c36295bde09c0 Mon Sep 17 00:00:00 2001
From: Andrew Tridgell <andrew@tridgell.net>
Date: Thu, 11 Apr 2019 19:50:46 +1000
Subject: [PATCH] HAL_ChibiOS: record reason for reset

allows us to tell if reset was due to watchdog
---
 libraries/AP_HAL_ChibiOS/hwdef/common/board.c |  2 +
 .../AP_HAL_ChibiOS/hwdef/common/watchdog.c    | 51 ++++++++++++++++++-
 .../AP_HAL_ChibiOS/hwdef/common/watchdog.h    | 10 ++++
 3 files changed, 61 insertions(+), 2 deletions(-)

diff --git a/libraries/AP_HAL_ChibiOS/hwdef/common/board.c b/libraries/AP_HAL_ChibiOS/hwdef/common/board.c
index 6d535e5921..7effb5a26b 100644
--- a/libraries/AP_HAL_ChibiOS/hwdef/common/board.c
+++ b/libraries/AP_HAL_ChibiOS/hwdef/common/board.c
@@ -18,6 +18,7 @@
 #include "hal.h"
 #include "usbcfg.h"
 #include "stm32_util.h"
+#include "watchdog.h"
 
 
 /*===========================================================================*/
@@ -233,6 +234,7 @@ void __early_init(void) {
 void __late_init(void) {
   halInit();
   chSysInit();
+  stm32_watchdog_save_reason();
 #if CH_CFG_USE_HEAP == TRUE
   malloc_init();
 #endif
diff --git a/libraries/AP_HAL_ChibiOS/hwdef/common/watchdog.c b/libraries/AP_HAL_ChibiOS/hwdef/common/watchdog.c
index a7275edd2f..10583fc7b3 100644
--- a/libraries/AP_HAL_ChibiOS/hwdef/common/watchdog.c
+++ b/libraries/AP_HAL_ChibiOS/hwdef/common/watchdog.c
@@ -8,13 +8,38 @@
 #ifndef IWDG_BASE
 #if defined(STM32H7)
 #define IWDG_BASE             0x58004800
-#elif defined(STM32F7) || defined(STM32F4) || defined(STM32F1)
+#elif defined(STM32F7) || defined(STM32F4)
+#define IWDG_BASE             0x40003000
+#elif defined(STM32F1)
 #define IWDG_BASE             0x40003000
 #else
-#error "Unknown IWDG_BASE"
+#error "Unsupported IWDG MCU config"
 #endif
 #endif
 
+#ifndef RCC_BASE
+#error "Unsupported IWDG RCC MCU config"
+#endif
+
+/*
+  defines for working out if the reset was from the watchdog
+ */
+#if defined(STM32H7)
+#define WDG_RESET_STATUS (*(__IO uint32_t *)(RCC_BASE + ))
+#define WDG_RESET_CLEAR (1U<<16)
+#define WDG_RESET_IS_IWDG (1U<<26)
+#elif defined(STM32F7) || defined(STM32F4)
+#define WDG_RESET_STATUS (*(__IO uint32_t *)(RCC_BASE + 0x74))
+#define WDG_RESET_CLEAR (1U<<24)
+#define WDG_RESET_IS_IWDG (1U<<29)
+#elif defined(STM32F1)
+#define WDG_RESET_STATUS (*(__IO uint32_t *)(RCC_BASE + 0x24))
+#define WDG_RESET_CLEAR (1U<<24)
+#define WDG_RESET_IS_IWDG (1U<<29)
+#else
+#error "Unsupported IWDG MCU config"
+#endif
+
 typedef struct
 {
   __IO uint32_t KR;   /*!< IWDG Key register,       Address offset: 0x00 */
@@ -46,3 +71,25 @@ void stm32_watchdog_pat(void)
 {
     IWDGD.KR = 0xAAAA;
 }
+
+static bool was_watchdog_reset;
+
+/*
+  save reason code for reset
+ */
+void stm32_watchdog_save_reason(void)
+{
+    if (WDG_RESET_STATUS & WDG_RESET_IS_IWDG) {
+        was_watchdog_reset = true;
+    }
+    WDG_RESET_STATUS = WDG_RESET_CLEAR;
+}
+
+/*
+  return true if reboot was from a watchdog reset
+ */
+bool stm32_was_watchdog_reset(void)
+{
+    return was_watchdog_reset;
+}
+
diff --git a/libraries/AP_HAL_ChibiOS/hwdef/common/watchdog.h b/libraries/AP_HAL_ChibiOS/hwdef/common/watchdog.h
index 9f1dc8417e..3310959626 100644
--- a/libraries/AP_HAL_ChibiOS/hwdef/common/watchdog.h
+++ b/libraries/AP_HAL_ChibiOS/hwdef/common/watchdog.h
@@ -14,6 +14,16 @@ void stm32_watchdog_init(void);
  */
 void stm32_watchdog_pat(void);
 
+/*
+  return true if reboot was from a watchdog reset
+ */
+bool stm32_was_watchdog_reset(void);
+
+/*
+  save the reset reason code
+ */
+void stm32_watchdog_save_reason(void);
+    
 #ifdef __cplusplus
 }
 #endif