Add bootloader for A/B update support

CMakeLists.txt

@@ -16,9 +16,21 @@ set(CMAKE_CXX_FLAGS "${COMMON_FLAGS}")
 set(CMAKE_C_STANDARD 11)
 set(CMAKE_CXX_STANDARD 20)
 
-set(COMMON_LINKER_FLAGS "-specs=nosys.specs -T${CMAKE_SOURCE_DIR}/STM32F103RCTx_FLASH.ld -lc -lm -lnosys -lstdc++ -Wl,--gc-sections -Wl,-Map=${CMAKE_BINARY_DIR}/hover.map,--cref")
+set(A_FIRMWARE_LINKER_FLAGS "-T${CMAKE_SOURCE_DIR}/STM32F103RCTx_FLASH_a.ld")
-set(CMAKE_EXE_LINKER_FLAGS "${COMMON_LINKER_FLAGS}")
+set(B_FIRMWARE_LINKER_FLAGS "-T${CMAKE_SOURCE_DIR}/STM32F103RCTx_FLASH_b.ld")
-set(CMAKE_SHARED_LINKER_FLAGS "${COMMON_LINKER_FLAGS}")
+set(AB_BOOT_FIRMWARE_LINKER_FLAGS "-T${CMAKE_SOURCE_DIR}/ab_boot/STM32F103RCTx_FLASH_boot.ld")
+set(COMMON_LINKER_FLAGS -specs=nosys.specs -lc -lm -lnosys -lstdc++ -Wl,--gc-sections "-Wl,-Map=${CMAKE_BINARY_DIR}/hover.map,--cref")
+
+set(A_FIRMWARE_APP_BASE 0x08002000)
+set(B_FIRMWARE_APP_BASE 0x08020800)
+
+get_property(IS_IN_TRY_COMPILE GLOBAL PROPERTY IN_TRY_COMPILE)
+if(IS_IN_TRY_COMPILE)
+    set(CMAKE_EXE_LINKER_FLAGS ${COMMON_LINKER_FLAGS} ${A_FIRMWARE_LINKER_FLAGS})
+    list(JOIN CMAKE_EXE_LINKER_FLAGS " " CMAKE_EXE_LINKER_FLAGS)
+    set(CMAKE_SHARED_LINKER_FLAGS ${COMMON_LINKER_FLAGS} ${A_FIRMWARE_LINKER_FLAGS})
+    list(JOIN CMAKE_SHARED_LINKER_FLAGS " " CMAKE_SHARED_LINKER_FLAGS)
+endif(IS_IN_TRY_COMPILE)
 
 project(bobbycar-controller-firmware ASM C CXX)
 
@@ -52,7 +64,6 @@ add_library(stm32_hal STATIC
     STM32CubeF1/Drivers/STM32F1xx_HAL_Driver/Src/stm32f1xx_hal_dma.c
     STM32CubeF1/Drivers/STM32F1xx_HAL_Driver/Src/stm32f1xx_hal_can.c
     startup_stm32f103xe.s
-    system_stm32f1xx.c
 )
 
 add_library(emanuel_foc_model STATIC
@@ -66,12 +77,18 @@ add_library(bobbycar-protocol INTERFACE
 )
 
 
-
+set(COMMON_SOURCES
+    config.h
+    defines.h
+    main.cpp
+    system_stm32f1xx.c
+)
 
 #
 # motor test
 #
-add_executable(motortest.elf config.h defines.h main.cpp)
+add_executable(motortest.elf ${COMMON_SOURCES})
+target_link_options(motortest.elf PRIVATE ${COMMON_LINKER_FLAGS} ${A_FIRMWARE_LINKER_FLAGS})
 target_link_libraries(motortest.elf stm32_hal emanuel_foc_model bobbycar-protocol)
 target_compile_options(motortest.elf PRIVATE
     -DMOTOR_TEST
@@ -88,16 +105,19 @@ target_compile_options(motortest.elf PRIVATE
 #    -DFEATURE_CAN
 #    -DCAN_LOG_UNKNOWN_ADDR
 #    -DIS_BACK
+
+    -DVECT_TAB_OFFSET=${A_FIRMWARE_APP_BASE}
 )
 add_custom_command(OUTPUT motortest.hex COMMAND arm-none-eabi-objcopy -O ihex motortest.elf motortest.hex DEPENDS motortest.elf)
 add_custom_command(OUTPUT motortest.bin COMMAND arm-none-eabi-objcopy -O binary -S motortest.elf motortest.bin DEPENDS motortest.elf)
 add_custom_target(motortest ALL SOURCES motortest.hex motortest.bin)
-add_custom_target(flash-motortest COMMAND st-flash --reset write motortest.bin 0x8000000 SOURCES motortest.bin DEPENDS motortest.bin)
+add_custom_target(flash-motortest COMMAND st-flash --reset write motortest.bin ${A_FIRMWARE_APP_BASE} SOURCES motortest.bin DEPENDS motortest.bin)
 
 #
 # motor test peter
 #
-add_executable(motortest_peter.elf config.h defines.h main.cpp)
+add_executable(motortest_peter.elf ${COMMON_SOURCES})
+target_link_options(motortest_peter.elf PRIVATE ${COMMON_LINKER_FLAGS} ${A_FIRMWARE_LINKER_FLAGS})
 target_link_libraries(motortest_peter.elf stm32_hal emanuel_foc_model bobbycar-protocol)
 target_compile_options(motortest_peter.elf PRIVATE
     #-DMOTOR_TEST
@@ -115,17 +135,20 @@ target_compile_options(motortest_peter.elf PRIVATE
         -DFEATURE_CAN
     #    -DCAN_LOG_UNKNOWN_ADDR
         -DIS_BACK
+
+    -DVECT_TAB_OFFSET=${A_FIRMWARE_APP_BASE}
 )
 add_custom_command(OUTPUT motortest_peter.hex COMMAND arm-none-eabi-objcopy -O ihex motortest_peter.elf motortest_peter.hex DEPENDS motortest_peter.elf)
 add_custom_command(OUTPUT motortest_peter.bin COMMAND arm-none-eabi-objcopy -O binary -S motortest_peter.elf motortest_peter.bin DEPENDS motortest_peter.elf)
 add_custom_target(motortest_peter ALL SOURCES motortest_peter.hex motortest_peter.bin)
-add_custom_target(flash-motortest_peter COMMAND st-flash --reset write motortest_peter.bin 0x8000000 SOURCES motortest_peter.bin DEPENDS motortest_peter.bin)
+add_custom_target(flash-motortest_peter COMMAND st-flash --reset write motortest_peter.bin ${A_FIRMWARE_APP_BASE} SOURCES motortest_peter.bin DEPENDS motortest_peter.bin)
 
 
 #
 # feedc0de front
 #
-add_executable(feedcode-front.elf config.h defines.h main.cpp)
+add_executable(feedcode-front.elf ${COMMON_SOURCES})
+target_link_options(feedcode-front.elf PRIVATE ${COMMON_LINKER_FLAGS} ${A_FIRMWARE_LINKER_FLAGS})
 target_link_libraries(feedcode-front.elf stm32_hal emanuel_foc_model bobbycar-protocol)
 target_compile_options(feedcode-front.elf PRIVATE
 #    -DMOTOR_TEST
@@ -142,16 +165,19 @@ target_compile_options(feedcode-front.elf PRIVATE
     -DFEATURE_CAN
 #    -DCAN_LOG_UNKNOWN_ADDR
 #    -DIS_BACK
+
+    -DVECT_TAB_OFFSET=${A_FIRMWARE_APP_BASE}
 )
 add_custom_command(OUTPUT feedcode-front.hex COMMAND arm-none-eabi-objcopy -O ihex feedcode-front.elf feedcode-front.hex DEPENDS feedcode-front.elf)
 add_custom_command(OUTPUT feedcode-front.bin COMMAND arm-none-eabi-objcopy -O binary -S feedcode-front.elf feedcode-front.bin DEPENDS feedcode-front.elf)
 add_custom_target(feedcode-front ALL SOURCES feedcode-front.hex feedcode-front.bin)
-add_custom_target(flash-feedcode-front COMMAND st-flash --reset write feedcode-front.bin 0x8000000 SOURCES feedcode-front.bin DEPENDS feedcode-front.bin)
+add_custom_target(flash-feedcode-front COMMAND st-flash --reset write feedcode-front.bin ${A_FIRMWARE_APP_BASE} SOURCES feedcode-front.bin DEPENDS feedcode-front.bin)
 
 #
 # feedc0de back
 #
-add_executable(feedcode-back.elf config.h defines.h main.cpp)
+add_executable(feedcode-back.elf ${COMMON_SOURCES})
+target_link_options(feedcode-back.elf PRIVATE ${COMMON_LINKER_FLAGS} ${A_FIRMWARE_LINKER_FLAGS})
 target_link_libraries(feedcode-back.elf stm32_hal emanuel_foc_model bobbycar-protocol)
 target_compile_options(feedcode-back.elf PRIVATE
 #    -DMOTOR_TEST
@@ -168,16 +194,19 @@ target_compile_options(feedcode-back.elf PRIVATE
     -DFEATURE_CAN
 #    -DCAN_LOG_UNKNOWN_ADDR
     -DIS_BACK
+
+    -DVECT_TAB_OFFSET=${A_FIRMWARE_APP_BASE}
 )
 add_custom_command(OUTPUT feedcode-back.hex COMMAND arm-none-eabi-objcopy -O ihex feedcode-back.elf feedcode-back.hex DEPENDS feedcode-back.elf)
 add_custom_command(OUTPUT feedcode-back.bin COMMAND arm-none-eabi-objcopy -O binary -S feedcode-back.elf feedcode-back.bin DEPENDS feedcode-back.elf)
 add_custom_target(feedcode-back ALL SOURCES feedcode-back.hex feedcode-back.bin)
-add_custom_target(flash-feedcode-back COMMAND st-flash --reset write feedcode-back.bin 0x8000000 SOURCES feedcode-back.bin DEPENDS feedcode-back.bin)
+add_custom_target(flash-feedcode-back COMMAND st-flash --reset write feedcode-back.bin ${A_FIRMWARE_APP_BASE} SOURCES feedcode-back.bin DEPENDS feedcode-back.bin)
 
 #
 # greyhash
 #
-add_executable(greyhash.elf config.h defines.h main.cpp)
+add_executable(greyhash.elf ${COMMON_SOURCES})
+target_link_options(greyhash.elf PRIVATE ${COMMON_LINKER_FLAGS} ${A_FIRMWARE_LINKER_FLAGS})
 target_link_libraries(greyhash.elf stm32_hal emanuel_foc_model bobbycar-protocol)
 target_compile_options(greyhash.elf PRIVATE
 #    -DMOTOR_TEST
@@ -194,14 +223,25 @@ target_compile_options(greyhash.elf PRIVATE
 #    -DFEATURE_CAN
 #    -DCAN_LOG_UNKNOWN_ADDR
 #    -DIS_BACK
+
+    -DVECT_TAB_OFFSET=${A_FIRMWARE_APP_BASE}
 )
 add_custom_command(OUTPUT greyhash.hex COMMAND arm-none-eabi-objcopy -O ihex greyhash.elf greyhash.hex DEPENDS greyhash.elf)
 add_custom_command(OUTPUT greyhash.bin COMMAND arm-none-eabi-objcopy -O binary -S greyhash.elf greyhash.bin DEPENDS greyhash.elf)
 add_custom_target(greyhash ALL SOURCES greyhash.hex greyhash.bin)
-add_custom_target(flash-greyhash COMMAND st-flash --reset write greyhash.bin 0x8000000 SOURCES greyhash.bin DEPENDS greyhash.bin)
+add_custom_target(flash-greyhash COMMAND st-flash --reset write greyhash.bin ${A_FIRMWARE_APP_BASE} SOURCES greyhash.bin DEPENDS greyhash.bin)
-
 
 
+add_executable(ab_boot.elf ab_boot/ab_boot.c system_stm32f1xx.c)
+target_link_options(ab_boot.elf PRIVATE ${COMMON_LINKER_FLAGS} ${AB_BOOT_FIRMWARE_LINKER_FLAGS})
+target_link_libraries(ab_boot.elf stm32_hal)
+target_compile_options(ab_boot.elf PRIVATE
+    -DVECT_TAB_OFFSET=0x00000000
+)
+add_custom_command(OUTPUT ab_boot.hex COMMAND arm-none-eabi-objcopy -O ihex ab_boot.elf ab_boot.hex DEPENDS ab_boot.elf)
+add_custom_command(OUTPUT ab_boot.bin COMMAND arm-none-eabi-objcopy -O binary -S ab_boot.elf ab_boot.bin DEPENDS ab_boot.elf)
+add_custom_target(ab_boot ALL SOURCES ab_boot.hex ab_boot.bin)
+add_custom_target(flash-boot COMMAND st-flash --reset write ab_boot.bin 0x08000000 SOURCES ab_boot.bin DEPENDS ab_boot.bin)
 
 
 # util targets

STM32F103RCTx_FLASH_a.ld

@@ -0,0 +1,168 @@
+/*
+*****************************************************************************
+**
+
+**  File        : LinkerScript.ld
+**
+**  Abstract    : Linker script for STM32F103RCTx Device with
+**                256KByte FLASH, 48KByte RAM
+**
+**                Set heap size, stack size and stack location according
+**                to application requirements.
+**
+**                Set memory bank area and size if external memory is used.
+**
+**  Target      : STMicroelectronics STM32
+**
+**
+**  Distribution: The file is distributed as is, without any warranty
+**                of any kind.
+**
+**  (c)Copyright Ac6.
+**  You may use this file as-is or modify it according to the needs of your
+**  project. Distribution of this file (unmodified or modified) is not
+**  permitted. Ac6 permit registered System Workbench for MCU users the
+**  rights to distribute the assembled, compiled & linked contents of this
+**  file as part of an application binary file, provided that it is built
+**  using the System Workbench for MCU toolchain.
+**
+*****************************************************************************
+*/
+
+/* Entry Point */
+ENTRY(Reset_Handler)
+
+/* Highest address of the user mode stack */
+_estack = 0x2000C000;    /* end of RAM */
+/* Generate a link error if heap and stack don't fit into RAM */
+_Min_Heap_Size = 0x200;      /* required amount of heap  */
+_Min_Stack_Size = 0x400; /* required amount of stack */
+
+/* Specify the memory areas */
+MEMORY
+{
+RAM (xrw)      : ORIGIN = 0x20000000, LENGTH =  48K
+FLASH (rx)     : ORIGIN = 0x08002000, LENGTH = 122K
+CONFIG (r)     : ORIGIN = 0x0803f800, LENGTH =   2K
+}
+
+/* Define output sections */
+SECTIONS
+{
+  /* The startup code goes first into FLASH */
+  .isr_vector :
+  {
+    . = ALIGN(4);
+    KEEP(*(.isr_vector)) /* Startup code */
+    . = ALIGN(4);
+  } >FLASH
+
+  /* The program code and other data goes into FLASH */
+  .text :
+  {
+    . = ALIGN(4);
+    *(.text)           /* .text sections (code) */
+    *(.text*)          /* .text* sections (code) */
+    *(.glue_7)         /* glue arm to thumb code */
+    *(.glue_7t)        /* glue thumb to arm code */
+    *(.eh_frame)
+
+    KEEP (*(.init))
+    KEEP (*(.fini))
+
+    . = ALIGN(4);
+    _etext = .;        /* define a global symbols at end of code */
+  } >FLASH
+
+  /* Constant data goes into FLASH */
+  .rodata :
+  {
+    . = ALIGN(4);
+    *(.rodata)         /* .rodata sections (constants, strings, etc.) */
+    *(.rodata*)        /* .rodata* sections (constants, strings, etc.) */
+    . = ALIGN(4);
+  } >FLASH
+
+  .ARM.extab   : { *(.ARM.extab* .gnu.linkonce.armextab.*) } >FLASH
+  .ARM : {
+    __exidx_start = .;
+    *(.ARM.exidx*)
+    __exidx_end = .;
+  } >FLASH
+
+  .preinit_array     :
+  {
+    PROVIDE_HIDDEN (__preinit_array_start = .);
+    KEEP (*(.preinit_array*))
+    PROVIDE_HIDDEN (__preinit_array_end = .);
+  } >FLASH
+  .init_array :
+  {
+    PROVIDE_HIDDEN (__init_array_start = .);
+    KEEP (*(SORT(.init_array.*)))
+    KEEP (*(.init_array*))
+    PROVIDE_HIDDEN (__init_array_end = .);
+  } >FLASH
+  .fini_array :
+  {
+    PROVIDE_HIDDEN (__fini_array_start = .);
+    KEEP (*(SORT(.fini_array.*)))
+    KEEP (*(.fini_array*))
+    PROVIDE_HIDDEN (__fini_array_end = .);
+  } >FLASH
+
+  /* used by the startup to initialize data */
+  _sidata = LOADADDR(.data);
+
+  /* Initialized data sections goes into RAM, load LMA copy after code */
+  .data :
+  {
+    . = ALIGN(4);
+    _sdata = .;        /* create a global symbol at data start */
+    *(.data)           /* .data sections */
+    *(.data*)          /* .data* sections */
+
+    . = ALIGN(4);
+    _edata = .;        /* define a global symbol at data end */
+  } >RAM AT> FLASH
+
+
+  /* Uninitialized data section */
+  . = ALIGN(4);
+  .bss :
+  {
+    /* This is used by the startup in order to initialize the .bss secion */
+    _sbss = .;         /* define a global symbol at bss start */
+    __bss_start__ = _sbss;
+    *(.bss)
+    *(.bss*)
+    *(COMMON)
+
+    . = ALIGN(4);
+    _ebss = .;         /* define a global symbol at bss end */
+    __bss_end__ = _ebss;
+  } >RAM
+
+  /* User_heap_stack section, used to check that there is enough RAM left */
+  ._user_heap_stack :
+  {
+    . = ALIGN(8);
+    PROVIDE ( end = . );
+    PROVIDE ( _end = . );
+    . = . + _Min_Heap_Size;
+    . = . + _Min_Stack_Size;
+    . = ALIGN(8);
+  } >RAM
+
+
+
+  /* Remove information from the standard libraries */
+  /DISCARD/ :
+  {
+    libc.a ( * )
+    libm.a ( * )
+    libgcc.a ( * )
+  }
+
+  .ARM.attributes 0 : { *(.ARM.attributes) }
+}

STM32F103RCTx_FLASH_b.ld

@@ -0,0 +1,168 @@
+/*
+*****************************************************************************
+**
+
+**  File        : LinkerScript.ld
+**
+**  Abstract    : Linker script for STM32F103RCTx Device with
+**                256KByte FLASH, 48KByte RAM
+**
+**                Set heap size, stack size and stack location according
+**                to application requirements.
+**
+**                Set memory bank area and size if external memory is used.
+**
+**  Target      : STMicroelectronics STM32
+**
+**
+**  Distribution: The file is distributed as is, without any warranty
+**                of any kind.
+**
+**  (c)Copyright Ac6.
+**  You may use this file as-is or modify it according to the needs of your
+**  project. Distribution of this file (unmodified or modified) is not
+**  permitted. Ac6 permit registered System Workbench for MCU users the
+**  rights to distribute the assembled, compiled & linked contents of this
+**  file as part of an application binary file, provided that it is built
+**  using the System Workbench for MCU toolchain.
+**
+*****************************************************************************
+*/
+
+/* Entry Point */
+ENTRY(Reset_Handler)
+
+/* Highest address of the user mode stack */
+_estack = 0x2000C000;    /* end of RAM */
+/* Generate a link error if heap and stack don't fit into RAM */
+_Min_Heap_Size = 0x200;      /* required amount of heap  */
+_Min_Stack_Size = 0x400; /* required amount of stack */
+
+/* Specify the memory areas */
+MEMORY
+{
+RAM (xrw)      : ORIGIN = 0x20000000, LENGTH =  48K
+FLASH (rx)     : ORIGIN = 0x08020800, LENGTH = 122K
+CONFIG (r)     : ORIGIN = 0x0803f800, LENGTH =   2K
+}
+
+/* Define output sections */
+SECTIONS
+{
+  /* The startup code goes first into FLASH */
+  .isr_vector :
+  {
+    . = ALIGN(4);
+    KEEP(*(.isr_vector)) /* Startup code */
+    . = ALIGN(4);
+  } >FLASH
+
+  /* The program code and other data goes into FLASH */
+  .text :
+  {
+    . = ALIGN(4);
+    *(.text)           /* .text sections (code) */
+    *(.text*)          /* .text* sections (code) */
+    *(.glue_7)         /* glue arm to thumb code */
+    *(.glue_7t)        /* glue thumb to arm code */
+    *(.eh_frame)
+
+    KEEP (*(.init))
+    KEEP (*(.fini))
+
+    . = ALIGN(4);
+    _etext = .;        /* define a global symbols at end of code */
+  } >FLASH
+
+  /* Constant data goes into FLASH */
+  .rodata :
+  {
+    . = ALIGN(4);
+    *(.rodata)         /* .rodata sections (constants, strings, etc.) */
+    *(.rodata*)        /* .rodata* sections (constants, strings, etc.) */
+    . = ALIGN(4);
+  } >FLASH
+
+  .ARM.extab   : { *(.ARM.extab* .gnu.linkonce.armextab.*) } >FLASH
+  .ARM : {
+    __exidx_start = .;
+    *(.ARM.exidx*)
+    __exidx_end = .;
+  } >FLASH
+
+  .preinit_array     :
+  {
+    PROVIDE_HIDDEN (__preinit_array_start = .);
+    KEEP (*(.preinit_array*))
+    PROVIDE_HIDDEN (__preinit_array_end = .);
+  } >FLASH
+  .init_array :
+  {
+    PROVIDE_HIDDEN (__init_array_start = .);
+    KEEP (*(SORT(.init_array.*)))
+    KEEP (*(.init_array*))
+    PROVIDE_HIDDEN (__init_array_end = .);
+  } >FLASH
+  .fini_array :
+  {
+    PROVIDE_HIDDEN (__fini_array_start = .);
+    KEEP (*(SORT(.fini_array.*)))
+    KEEP (*(.fini_array*))
+    PROVIDE_HIDDEN (__fini_array_end = .);
+  } >FLASH
+
+  /* used by the startup to initialize data */
+  _sidata = LOADADDR(.data);
+
+  /* Initialized data sections goes into RAM, load LMA copy after code */
+  .data :
+  {
+    . = ALIGN(4);
+    _sdata = .;        /* create a global symbol at data start */
+    *(.data)           /* .data sections */
+    *(.data*)          /* .data* sections */
+
+    . = ALIGN(4);
+    _edata = .;        /* define a global symbol at data end */
+  } >RAM AT> FLASH
+
+
+  /* Uninitialized data section */
+  . = ALIGN(4);
+  .bss :
+  {
+    /* This is used by the startup in order to initialize the .bss secion */
+    _sbss = .;         /* define a global symbol at bss start */
+    __bss_start__ = _sbss;
+    *(.bss)
+    *(.bss*)
+    *(COMMON)
+
+    . = ALIGN(4);
+    _ebss = .;         /* define a global symbol at bss end */
+    __bss_end__ = _ebss;
+  } >RAM
+
+  /* User_heap_stack section, used to check that there is enough RAM left */
+  ._user_heap_stack :
+  {
+    . = ALIGN(8);
+    PROVIDE ( end = . );
+    PROVIDE ( _end = . );
+    . = . + _Min_Heap_Size;
+    . = . + _Min_Stack_Size;
+    . = ALIGN(8);
+  } >RAM
+
+
+
+  /* Remove information from the standard libraries */
+  /DISCARD/ :
+  {
+    libc.a ( * )
+    libm.a ( * )
+    libgcc.a ( * )
+  }
+
+  .ARM.attributes 0 : { *(.ARM.attributes) }
+}

ab_boot/STM32F103RCTx_FLASH_boot.ld

@@ -42,7 +42,8 @@ _Min_Stack_Size = 0x400; /* required amount of stack */
 MEMORY
 {
 RAM (xrw)      : ORIGIN = 0x20000000, LENGTH = 48K
-FLASH (rx)      : ORIGIN = 0x8000000, LENGTH = 256K
+FLASH (rx)     : ORIGIN = 0x08000000, LENGTH =  8K
+CONFIG(r)      : ORIGIN = 0x0803f800, LENGTH =  2K
 }
 
 /* Define output sections */
@@ -114,7 +115,7 @@ SECTIONS
   _sidata = LOADADDR(.data);
 
   /* Initialized data sections goes into RAM, load LMA copy after code */
-  .data : 
+  .data :
   {
     . = ALIGN(4);
     _sdata = .;        /* create a global symbol at data start */
@@ -125,7 +126,7 @@ SECTIONS
     _edata = .;        /* define a global symbol at data end */
   } >RAM AT> FLASH
 
-  
+
   /* Uninitialized data section */
   . = ALIGN(4);
   .bss :
@@ -153,7 +154,7 @@ SECTIONS
     . = ALIGN(8);
   } >RAM
 
-  
+
 
   /* Remove information from the standard libraries */
   /DISCARD/ :
@@ -165,5 +166,3 @@ SECTIONS
 
   .ARM.attributes 0 : { *(.ARM.attributes) }
 }
-
-

ab_boot/ab_boot.c

@@ -0,0 +1,31 @@
+#include <stdint.h>
+
+#include "stm32f1xx_hal.h"
+#include "ab_boot.h"
+
+int main()
+{
+    struct ab_boot_config *config = (struct ab_boot_config *)CONFIG_START;
+
+    uint32_t *bootp;
+    if (config->boot_partition >= FLASH_START &&
+        config->boot_partition < FLASH_END &&
+        (config->boot_partition & 3) == 0)
+    {
+        bootp = (uint32_t *)config->boot_partition;
+    }
+    else
+    {
+        bootp = (uint32_t *)APP_A_START;
+    }
+
+    uint32_t sp = bootp[0];
+    uint32_t entry = bootp[1];
+    asm volatile(
+        "   mov sp, %0    \n"
+        "   bx  %1        \n"
+        "1: b   1b        \n"
+        :
+        : "r" (sp), "r" (entry)
+    );
+}

ab_boot/ab_boot.h

@@ -0,0 +1,15 @@
+#pragma once
+
+#include <stdint.h>
+
+#define CONFIG_START 0x0803f800
+#define FLASH_START  0x08000000
+#define FLASH_END    0x08040000
+
+#define APP_A_START  0x08002000
+#define APP_B_START  0x08020800
+
+struct ab_boot_config
+{
+    uint32_t boot_partition;
+};

system_stm32f1xx.c

@@ -110,9 +110,11 @@
 /*!< Uncomment the following line if you need to relocate your vector Table in
      Internal SRAM. */
 /* #define VECT_TAB_SRAM */
+#if !defined(VECT_TAB_OFFSET)
+#warning VECT_TAB_OFFSET is not defined, using default of 0x00000000U
 #define VECT_TAB_OFFSET 0x00000000U /*!< Vector Table base offset field. \
                                  This value must be a multiple of 0x200. */
-
+#endif /* VECT_TAB_OFFSET */
 
 /**
   * @}