Convert F7s to use RTC backup register based persistent memory

make/mcu/STM32F7.mk

@@ -41,8 +41,6 @@ EXCLUDES        = stm32f7xx_hal_can.c \
                   stm32f7xx_hal_nor.c \
                   stm32f7xx_hal_qspi.c \
                   stm32f7xx_hal_rng.c \
-                  stm32f7xx_hal_rtc.c \
-                  stm32f7xx_hal_rtc_ex.c \
                   stm32f7xx_hal_sai.c \
                   stm32f7xx_hal_sai_ex.c \
                   stm32f7xx_hal_sd.c \
@@ -179,6 +177,7 @@ MCU_COMMON_SRC = \
             drivers/light_ws2811strip_hal.c \
             drivers/transponder_ir_io_hal.c \
             drivers/bus_spi_ll.c \
+            drivers/persistent.c \
             drivers/pwm_output_dshot_hal.c \
             drivers/timer_hal.c \
             drivers/timer_stm32f7xx.c \

src/main/drivers/system_stm32f7xx.c

@@ -29,6 +29,7 @@
 #include "drivers/exti.h"
 #include "drivers/nvic.h"
 #include "drivers/system.h"
+#include "drivers/persistent.h"
 
 #include "stm32f7xx_ll_cortex.h"
 
@@ -44,8 +45,7 @@ void systemReset(void)
 
 void systemResetToBootloader(void)
 {
-    (*(__IO uint32_t *) (BKPSRAM_BASE + 4)) = 0xDEADBEEF;   // flag that will be readable after reboot
-
+    persistentObjectWrite(PERSISTENT_OBJECT_BOOTLOADER_REQUEST, 0xDEADBEEF);
     __disable_irq();
     NVIC_SystemReset();
 }
@@ -154,8 +154,6 @@ bool isMPUSoftReset(void)
 
 void systemInit(void)
 {
-    checkForBootLoaderRequest();
-
     //  Mark ITCM-RAM as read-only
     LL_MPU_ConfigRegion(LL_MPU_REGION_NUMBER0, 0, RAMITCM_BASE, LL_MPU_REGION_SIZE_16KB | LL_MPU_REGION_PRIV_RO_URO);
     LL_MPU_Enable(LL_MPU_CTRL_PRIVILEGED_DEFAULT);
@@ -188,27 +186,23 @@ void systemInit(void)
 }
 
 void(*bootJump)(void);
+
 void checkForBootLoaderRequest(void)
 {
-    uint32_t bt;
-    __PWR_CLK_ENABLE();
-    __BKPSRAM_CLK_ENABLE();
-    HAL_PWR_EnableBkUpAccess();
+    uint32_t bootloaderRequest = persistentObjectRead(PERSISTENT_OBJECT_BOOTLOADER_REQUEST);
 
-    bt = (*(__IO uint32_t *) (BKPSRAM_BASE + 4)) ;
-    if ( bt == 0xDEADBEEF ) {
-        (*(__IO uint32_t *) (BKPSRAM_BASE + 4)) =  0xCAFEFEED; // Reset our trigger
-        // Backup SRAM is write-back by default, ensure value actually reaches memory
-        // Another solution would be marking BKPSRAM as write-through in Memory Protection Unit settings
-        SCB_CleanDCache_by_Addr((uint32_t *) (BKPSRAM_BASE + 4), sizeof(uint32_t));
+    persistentObjectWrite(PERSISTENT_OBJECT_BOOTLOADER_REQUEST, 0xCAFEFEED);
 
-        void (*SysMemBootJump)(void);
-        __SYSCFG_CLK_ENABLE();
-        SYSCFG->MEMRMP |= SYSCFG_MEM_BOOT_ADD0 ;
-        uint32_t p =  (*((uint32_t *) 0x1ff00000));
-        __set_MSP(p); //Set the main stack pointer to its defualt values
-        SysMemBootJump = (void (*)(void)) (*((uint32_t *) 0x1ff00004)); // Point the PC to the System Memory reset vector (+4)
-        SysMemBootJump();
-        while (1);
+    if (bootloaderRequest != 0xDEADBEEF) {
+        return;
     }
+
+    void (*SysMemBootJump)(void);
+    __SYSCFG_CLK_ENABLE();
+    SYSCFG->MEMRMP |= SYSCFG_MEM_BOOT_ADD0 ;
+    uint32_t p =  (*((uint32_t *) 0x1ff00000));
+    __set_MSP(p); //Set the main stack pointer to its defualt values
+    SysMemBootJump = (void (*)(void)) (*((uint32_t *) 0x1ff00004)); // Point the PC to the System Memory reset vector (+4)
+    SysMemBootJump();
+    while (1);
 }

src/main/startup/startup_stm32f722xx.s

@@ -83,6 +83,9 @@ defined in linker script */
 Reset_Handler:  
   ldr   sp, =_estack      /* set stack pointer */
 
+  bl persistentObjectInit
+  bl checkForBootLoaderRequest
+
 /* Copy the data segment initializers from flash to SRAM */  
   movs  r1, #0
   b  LoopCopyDataInit

src/main/startup/startup_stm32f745xx.s

@@ -83,6 +83,9 @@ defined in linker script */
 Reset_Handler:  
   ldr   sp, =_estack      /* set stack pointer */
 
+  bl persistentObjectInit
+  bl checkForBootLoaderRequest
+
 /* Copy the data segment initializers from flash to SRAM */  
   movs  r1, #0
   b  LoopCopyDataInit

src/main/startup/startup_stm32f746xx.s

@@ -83,6 +83,9 @@ defined in linker script */
 Reset_Handler:  
   ldr   sp, =_estack      /* set stack pointer */
 
+  bl persistentObjectInit
+  bl checkForBootLoaderRequest
+
 /* Copy the data segment initializers from flash to SRAM */  
   movs  r1, #0
   b  LoopCopyDataInit

src/main/startup/startup_stm32f765xx.s

@@ -83,6 +83,9 @@ defined in linker script */
 Reset_Handler:  
   ldr   sp, =_estack      /* set stack pointer */
 
+  bl persistentObjectInit
+  bl checkForBootLoaderRequest
+
 /* Copy the data segment initializers from flash to SRAM */  
   movs  r1, #0
   b  LoopCopyDataInit

src/main/target/stm32f7xx_hal_conf.h

@@ -69,7 +69,7 @@
 /* #define HAL_LTDC_MODULE_ENABLED   */
 /* #define HAL_QSPI_MODULE_ENABLED   */
 /* #define HAL_RNG_MODULE_ENABLED   */
-/* #define HAL_RTC_MODULE_ENABLED   */
+#define HAL_RTC_MODULE_ENABLED
 /* #define HAL_SAI_MODULE_ENABLED   */
 /* #define HAL_SD_MODULE_ENABLED   */
 /* #define HAL_MMC_MODULE_ENABLED   */

src/main/target/system_stm32f7xx.c

@@ -66,6 +66,7 @@
 #include "stm32f7xx.h"
 #include "system_stm32f7xx.h"
 #include "platform.h"
+#include "drivers/persistent.h"
 
 #if !defined  (HSE_VALUE)
   #define HSE_VALUE    ((uint32_t)8000000) /*!< Default value of the External oscillator in Hz */
@@ -259,30 +260,32 @@ static const pllConfig_t overclockLevels[] = {
   { 480, RCC_PLLP_DIV2, 10 }, // 240 MHz
 };
 
+#if 0
 // 8 bytes of memory located at the very end of RAM, expected to be unoccupied
 #define REQUEST_OVERCLOCK               (*(__IO uint32_t *) (BKPSRAM_BASE + 8))
 #define CURRENT_OVERCLOCK_LEVEL         (*(__IO uint32_t *) (BKPSRAM_BASE + 12))
 #define REQUEST_OVERCLOCK_MAGIC_COOKIE  0xBABEFACE
+#endif
 
 void SystemInitOC(void) {
+#if 0
     __PWR_CLK_ENABLE();
     __BKPSRAM_CLK_ENABLE();
     HAL_PWR_EnableBkUpAccess();
+#endif
 
-    if (REQUEST_OVERCLOCK_MAGIC_COOKIE == REQUEST_OVERCLOCK) {
-      const uint32_t overclockLevel = CURRENT_OVERCLOCK_LEVEL;
+    uint32_t currentOverclockLevel = persistentObjectRead(PERSISTENT_OBJECT_OVERCLOCK_LEVEL);
 
-      /* PLL setting for overclocking */
-      if (overclockLevel < ARRAYLEN(overclockLevels)) {
-        const pllConfig_t * const pll = overclockLevels + overclockLevel;
-
-        pll_n = pll->n;
-        pll_p = pll->p;
-        pll_q = pll->q;
-      }
-
-      REQUEST_OVERCLOCK = 0;
+    if (currentOverclockLevel >= ARRAYLEN(overclockLevels)) {
+      return;
     }
+
+    /* PLL setting for overclocking */
+    const pllConfig_t * const pll = overclockLevels + currentOverclockLevel;
+
+    pll_n = pll->n;
+    pll_p = pll->p;
+    pll_q = pll->q;
 }
 
 void OverclockRebootIfNecessary(uint32_t overclockLevel)
@@ -295,8 +298,7 @@ void OverclockRebootIfNecessary(uint32_t overclockLevel)
 
     // Reboot to adjust overclock frequency
     if (SystemCoreClock != (pll->n / pll->p) * 1000000U) {
-        REQUEST_OVERCLOCK = REQUEST_OVERCLOCK_MAGIC_COOKIE;
-        CURRENT_OVERCLOCK_LEVEL = overclockLevel;
+        persistentObjectWrite(PERSISTENT_OBJECT_OVERCLOCK_LEVEL, overclockLevel);
         __disable_irq();
         NVIC_SystemReset();
     }