Introdce BOOTLOADER_MAGIC_FORCE; add press-game-on-boot-to-abort.

Author: BrianPugh

Core/Src/main.c

@@ -15,12 +15,15 @@
 #define BANK_2_ADDRESS 0x08100000
 #define SD_BOOTLOADER_ADDRESS 0x08032000
 
+// Other software (like retro-go) should set this value
 #define BOOTLOADER_MAGIC 0x544F4F42  // "BOOT"
+
+// Intended for internal-use only; bypasses other checks
+#define BOOTLOADER_MAGIC_FORCE 0x45435246  // "FRCE"
+
 #define BOOTLOADER_MAGIC_ADDRESS ((uint32_t *)0x2001FFF8)
 #define BOOTLOADER_JUMP_ADDRESS ((uint32_t **)0x2001FFFC)
 
-static void MX_RTC_Init(RTC_HandleTypeDef *hrtc);
-
 static void  __attribute__((naked)) start_app(void (* const pc)(void), uint32_t sp) {
     __asm("           \n\
           msr msp, r1 /* load r1 into MSP */\n\
@@ -29,7 +32,7 @@ static void  __attribute__((naked)) start_app(void (* const pc)(void), uint32_t
 }
 
 static inline void set_bootloader(uint32_t address){
-    *BOOTLOADER_MAGIC_ADDRESS = BOOTLOADER_MAGIC;
+    *BOOTLOADER_MAGIC_ADDRESS = BOOTLOADER_MAGIC_FORCE;
     *BOOTLOADER_JUMP_ADDRESS = (uint32_t *)address;
 }
 
@@ -41,20 +44,46 @@ static inline void set_bootloader(uint32_t address){
  * So to run that app, set those values and execute a reset.
  */
 void bootloader(){
-    if(*BOOTLOADER_MAGIC_ADDRESS == BOOTLOADER_MAGIC) {
+    if(*BOOTLOADER_MAGIC_ADDRESS == BOOTLOADER_MAGIC_FORCE) {
         *BOOTLOADER_MAGIC_ADDRESS = 0;
         uint32_t sp = (*BOOTLOADER_JUMP_ADDRESS)[0];
         uint32_t pc = (*BOOTLOADER_JUMP_ADDRESS)[1];
         start_app((void (* const)(void)) pc, (uint32_t) sp);
     }
+
     HAL_Init();
-    __HAL_RCC_CRS_CLK_ENABLE();
-    HAL_PWR_EnableBkUpAccess();   // Enable backup domain access
-    __HAL_RCC_RTC_ENABLE();       // Enable RTC clock
-    RTC_HandleTypeDef hrtc;
-    MX_RTC_Init(&hrtc);
-    uint32_t rtc_backup_value = HAL_RTCEx_BKUPRead(&hrtc, RTC_BKP_DR0);
-    if(rtc_backup_value == BOOTLOADER_MAGIC){
+
+    HAL_PWR_EnableBkUpAccess();
+    __HAL_RCC_RTC_ENABLE();
+    __HAL_RCC_GPIOC_CLK_ENABLE();
+
+    RTC_HandleTypeDef hrtc = {0};
+    hrtc.Instance = RTC;
+    // Note: Don't need to call HAL_RTC_Init() since we're just reading backup register
+
+    GPIO_InitTypeDef GPIO_InitStruct = {0};
+    GPIO_InitStruct.Pin = BTN_GAME_Pin;
+    GPIO_InitStruct.Mode = GPIO_MODE_INPUT;
+    GPIO_InitStruct.Pull = GPIO_PULLUP;  // Button connects to GND.
+    GPIO_InitStruct.Speed = GPIO_SPEED_FREQ_LOW;
+
+    HAL_GPIO_Init(BTN_GAME_GPIO_Port, &GPIO_InitStruct);
+
+    if(HAL_GPIO_ReadPin(BTN_GAME_GPIO_Port, BTN_GAME_Pin) == GPIO_PIN_RESET) {
+        // If GAME is pressed: reset all triggers that might cause us to dual-boot.
+        *BOOTLOADER_MAGIC_ADDRESS = 0;
+        HAL_RTCEx_BKUPWrite(&hrtc, RTC_BKP_DR0, 0);
+    }
+
+    if(*BOOTLOADER_MAGIC_ADDRESS == BOOTLOADER_MAGIC) {
+        *BOOTLOADER_MAGIC_ADDRESS = 0;
+        uint32_t sp = (*BOOTLOADER_JUMP_ADDRESS)[0];
+        uint32_t pc = (*BOOTLOADER_JUMP_ADDRESS)[1];
+        start_app((void (* const)(void)) pc, (uint32_t) sp);
+    }
+
+
+    if(HAL_RTCEx_BKUPRead(&hrtc, RTC_BKP_DR0) == BOOTLOADER_MAGIC){
 #if SD_BOOTLOADER
         uint32_t sp = *((uint32_t*)SD_BOOTLOADER_ADDRESS);
         uint32_t pc = *((uint32_t*)SD_BOOTLOADER_ADDRESS + 1);
@@ -122,16 +151,19 @@ gamepad_t read_buttons() {
         NVIC_SystemReset();
     }
 #endif
+
 #if CLOCK_ONLY
     if(gamepad & GAMEPAD_GAME){
 #else
     if((gamepad & GAMEPAD_LEFT) && (gamepad & GAMEPAD_GAME)){
 #endif
+
 #if SD_BOOTLOADER
         set_bootloader(SD_BOOTLOADER_ADDRESS);
 #else
         set_bootloader(BANK_2_ADDRESS);
 #endif
+
         NVIC_SystemReset();
     }
 
@@ -229,38 +261,6 @@ gnw_mode_t get_gnw_mode(){
 }
 #endif
 
-/**
-  * @brief RTC Initialization Function
-  * @param None
-  * @retval None
-  */
-static void MX_RTC_Init(RTC_HandleTypeDef *hrtc)
-{
-
-  /* USER CODE BEGIN RTC_Init 0 */
-
-  /* USER CODE END RTC_Init 0 */
-
-  /* USER CODE BEGIN RTC_Init 1 */
-
-  /* USER CODE END RTC_Init 1 */
-  /** Initialize RTC Only
-  */
-  hrtc->Instance = RTC;
-  hrtc->Init.HourFormat = RTC_HOURFORMAT_24;
-  hrtc->Init.AsynchPrediv = 127; // Recommended value from application note for LSE, the higher the value the better the accuracy and power consumption
-  hrtc->Init.SynchPrediv = 255; // Recommended value from application note for LSE
-  hrtc->Init.OutPut = RTC_OUTPUT_DISABLE;
-  hrtc->Init.OutPutPolarity = RTC_OUTPUT_POLARITY_HIGH;
-  hrtc->Init.OutPutType = RTC_OUTPUT_TYPE_OPENDRAIN;
-  hrtc->Init.OutPutRemap = RTC_OUTPUT_REMAP_NONE;
-  HAL_RTC_Init(hrtc);
-
-  /* USER CODE BEGIN Check_RTC_BKUP */
-  return; // Retain RTC values on boot
-}
-
-
 void NMI_Handler(void) {
     __BKPT(0);
 }

Makefile

@@ -20,12 +20,13 @@ Core/Src/main.c \
 Core/Src/system_stm32h7xx.c \
 Core/lzma/LzmaDec.c \
 Drivers/STM32H7xx_HAL_Driver/Src/stm32h7xx_hal.c \
-Drivers/STM32H7xx_HAL_Driver/Src/stm32h7xx_hal_rtc_ex.c \
-Drivers/STM32H7xx_HAL_Driver/Src/stm32h7xx_hal_rtc.c \
-Drivers/STM32H7xx_HAL_Driver/Src/stm32h7xx_hal_rcc_ex.c \
-Drivers/STM32H7xx_HAL_Driver/Src/stm32h7xx_hal_rcc.c \
 Drivers/STM32H7xx_HAL_Driver/Src/stm32h7xx_hal_cortex.c \
+Drivers/STM32H7xx_HAL_Driver/Src/stm32h7xx_hal_gpio.c \
 Drivers/STM32H7xx_HAL_Driver/Src/stm32h7xx_hal_pwr.c \
+Drivers/STM32H7xx_HAL_Driver/Src/stm32h7xx_hal_rcc.c \
+Drivers/STM32H7xx_HAL_Driver/Src/stm32h7xx_hal_rcc_ex.c \
+Drivers/STM32H7xx_HAL_Driver/Src/stm32h7xx_hal_rtc.c \
+Drivers/STM32H7xx_HAL_Driver/Src/stm32h7xx_hal_rtc_ex.c \
 
 
 # ASM sources