From 2b7b499c634820c9882494adba03a048fc0725d0 Mon Sep 17 00:00:00 2001
From: Andrew Tridgell <andrew@tridgell.net>
Date: Wed, 27 Jun 2018 18:46:34 +1000
Subject: [PATCH] HAL_ChibiOS: added support for RTC sig for fast boot

---
 libraries/AP_HAL_ChibiOS/Scheduler.cpp        |  5 ++-
 .../AP_HAL_ChibiOS/hwdef/common/stm32_util.c  | 33 +++++++++++++++++++
 .../AP_HAL_ChibiOS/hwdef/common/stm32_util.h  | 12 +++++++
 3 files changed, 49 insertions(+), 1 deletion(-)

diff --git a/libraries/AP_HAL_ChibiOS/Scheduler.cpp b/libraries/AP_HAL_ChibiOS/Scheduler.cpp
index 36e65333ff..a0d67e7f1d 100644
--- a/libraries/AP_HAL_ChibiOS/Scheduler.cpp
+++ b/libraries/AP_HAL_ChibiOS/Scheduler.cpp
@@ -32,6 +32,7 @@
 #include <DataFlash/DataFlash.h>
 #include <AP_Scheduler/AP_Scheduler.h>
 #include <AP_BoardConfig/AP_BoardConfig.h>
+#include "hwdef/common/stm32_util.h"
 #include "shared_dma.h"
 #include "sdcard.h"
 
@@ -232,7 +233,6 @@ void Scheduler::register_timer_failsafe(AP_HAL::Proc failsafe, uint32_t period_u
     _failsafe = failsafe;
 }
 
-extern void Reset_Handler();
 void Scheduler::reboot(bool hold_in_bootloader)
 {
     // disarm motors to ensure they are off during a bootloader upload
@@ -245,6 +245,9 @@ void Scheduler::reboot(bool hold_in_bootloader)
     // stop sdcard driver, if active
     sdcard_stop();
 
+    // setup RTC for fast reboot
+    set_fast_reboot(hold_in_bootloader?RTC_BOOT_HOLD:RTC_BOOT_FAST);
+
     // disable all interrupt sources
     port_disable();
     
diff --git a/libraries/AP_HAL_ChibiOS/hwdef/common/stm32_util.c b/libraries/AP_HAL_ChibiOS/hwdef/common/stm32_util.c
index bf64dcde54..1ba5c1ef07 100644
--- a/libraries/AP_HAL_ChibiOS/hwdef/common/stm32_util.c
+++ b/libraries/AP_HAL_ChibiOS/hwdef/common/stm32_util.c
@@ -218,3 +218,36 @@ uint32_t get_fattime()
     
     return fattime;
 }
+
+// get RTC backup register 0
+static uint32_t get_rtc_backup0(void)
+{
+	return RTC->BKP0R;
+}
+
+// set RTC backup register 0
+static void set_rtc_backup0(uint32_t v)
+{
+    if ((RCC->BDCR & RCC_BDCR_RTCEN) == 0) {
+        RCC->BDCR |= STM32_RTCSEL;
+        RCC->BDCR |= RCC_BDCR_RTCEN;
+    }
+#ifdef PWR_CR_DBP
+    PWR->CR |= PWR_CR_DBP;
+#else
+    PWR->CR1 |= PWR_CR1_DBP;
+#endif
+    RTC->BKP0R = v;
+}
+
+// see if RTC registers is setup for a fast reboot
+enum rtc_boot_magic check_fast_reboot(void)
+{
+    return (enum rtc_boot_magic)get_rtc_backup0();
+}
+
+// set RTC register for a fast reboot
+void set_fast_reboot(enum rtc_boot_magic v)
+{
+    set_rtc_backup0(v);
+}
diff --git a/libraries/AP_HAL_ChibiOS/hwdef/common/stm32_util.h b/libraries/AP_HAL_ChibiOS/hwdef/common/stm32_util.h
index 96bda180ca..2caa4c4d4d 100644
--- a/libraries/AP_HAL_ChibiOS/hwdef/common/stm32_util.h
+++ b/libraries/AP_HAL_ChibiOS/hwdef/common/stm32_util.h
@@ -52,6 +52,18 @@ uint32_t get_fattime(void);
 #define OTP_BASE 0x1ff0f000
 #define OTP_SIZE 1024
 #endif
+
+enum rtc_boot_magic {
+    RTC_BOOT_OFF  = 0,
+    RTC_BOOT_HOLD = 0xb0070001,
+    RTC_BOOT_FAST = 0xb0070002
+};
+    
+// see if RTC registers is setup for a fast reboot
+enum rtc_boot_magic check_fast_reboot(void);
+
+// set RTC register for a fast reboot
+void set_fast_reboot(enum rtc_boot_magic v);
     
 #ifdef __cplusplus
 }