src/platform/APM32/persistent_apm32.c

   1 /*
   2  * This file is part of Betaflight.
   3  *
   4  * Betaflight is free software. You can redistribute this software
   5  * and/or modify this software under the terms of the GNU General
   6  * Public License as published by the Free Software Foundation,
   7  * either version 3 of the License, or (at your option) any later
   8  * version.
   9  *
  10  * Betaflight is distributed in the hope that it will be useful,
  11  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  12  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
  13  *
  14  * See the GNU General Public License for more details.
  15  *
  16  * You should have received a copy of the GNU General Public
  17  * License along with this software.
  18  *
  19  * If not, see <http://www.gnu.org/licenses/>.
  20  */
  21
  22 /*
  23  * An implementation of persistent data storage utilizing RTC backup data register.
  24  * Retains values written across software resets and boot loader activities.
  25  */
  26
  27 #include <stdint.h>
  28 #include "platform.h"
  29
  30 #include "drivers/persistent.h"
  31 #include "drivers/system.h"
  32
  33 #define PERSISTENT_OBJECT_MAGIC_VALUE (('B' << 24)|('e' << 16)|('f' << 8)|('1' << 0))
  34
  35 uint32_t persistentObjectRead(persistentObjectId_e id)
  36 {
  37     RTC_HandleTypeDef rtcHandle = { .Instance = RTC };
  38
  39     uint32_t value = DAL_RTCEx_BKUPRead(&rtcHandle, id);
  40
  41     return value;
  42 }
  43
  44 void persistentObjectWrite(persistentObjectId_e id, uint32_t value)
  45 {
  46     RTC_HandleTypeDef rtcHandle = { .Instance = RTC };
  47
  48     DAL_RTCEx_BKUPWrite(&rtcHandle, id, value);
  49
  50 #ifdef USE_SPRACING_PERSISTENT_RTC_WORKAROUND
  51     // Also write the persistent location used by the bootloader to support DFU etc.
  52     if (id == PERSISTENT_OBJECT_RESET_REASON) {
  53         // SPRACING firmware sometimes enters DFU mode when MSC mode is requested
  54         if (value == RESET_MSC_REQUEST) {
  55             value = RESET_NONE;
  56         }
  57         DAL_RTCEx_BKUPWrite(&rtcHandle, PERSISTENT_OBJECT_RESET_REASON_FWONLY, value);
  58     }
  59 #endif
  60 }
  61
  62 static void persistentObjectRTCEnable(void)
  63 {
  64     RTC_HandleTypeDef rtcHandle = { .Instance = RTC };
  65
  66     __DAL_RCM_PMU_CLK_ENABLE(); // Enable Access to PMU
  67
  68     DAL_PMU_EnableBkUpAccess(); // Disable backup domain protection
  69
  70     // We don't need a clock source for RTC itself. Skip it.
  71
  72     __DAL_RTC_WRITEPROTECTION_ENABLE(&rtcHandle);  // Reset sequence
  73     __DAL_RTC_WRITEPROTECTION_DISABLE(&rtcHandle); // Apply sequence
  74 }
  75
  76 void persistentObjectInit(void)
  77 {
  78     // Configure and enable RTC for backup register access
  79
  80     persistentObjectRTCEnable();
  81
  82     // XXX Magic value checking may be sufficient
  83
  84     uint32_t wasSoftReset;
  85
  86     wasSoftReset = RCM->CSTS & RCM_CSTS_SWRSTFLG;
  87
  88     if (!wasSoftReset || (persistentObjectRead(PERSISTENT_OBJECT_MAGIC) != PERSISTENT_OBJECT_MAGIC_VALUE)) {
  89         for (int i = 1; i < PERSISTENT_OBJECT_COUNT; i++) {
  90             persistentObjectWrite(i, 0);
  91         }
  92         persistentObjectWrite(PERSISTENT_OBJECT_MAGIC, PERSISTENT_OBJECT_MAGIC_VALUE);
  93     }
  94 }