Soft 468 jumping back to bootloader

libraries/ms-bootloader/README.md

@@ -0,0 +1,18 @@
+<!--
+    General guidelines
+    These are just guidelines, not strict rules - document however seems best.
+    A README for a firmware-only project (e.g. Babydriver, MU, bootloader, CAN explorer) should answer the following questions:
+        - What is it?
+        - What problem does it solve?
+        - How do I use it? (with usage examples / example commands, etc)
+        - How does it work? (architectural overview)
+    A README for a board project (powering a hardware board, e.g. power distribution, centre console, charger, BMS carrier) should answer the following questions:
+        - What is the purpose of the board?
+        - What are all the things that the firmware needs to do?
+        - How does it fit into the overall system?
+        - How does it work? (architectural overview, e.g. what each module's purpose is or how data flows through the firmware)
+-->
+
+# ms-bootloader
+
+ms-bootloader currently contains the jump_to_bootloader project, which allows an application to jump back to the bootloader on command

libraries/ms-bootloader/inc/jump.h

@@ -0,0 +1,8 @@
+#pragma once
+// This library allows client to jump to an arbitrary memory address
+#include <stdint.h>
+#include <stdnoreturn.h>
+#include <string.h>
+
+// Reset main stack pointer to main stack pointer, and jump to program counter
+noreturn void perform_jump(uint32_t sp, uint32_t pc);

libraries/ms-bootloader/inc/jump_to_bootloader.h

@@ -0,0 +1,4 @@
+#pragma once
+
+// Jump to the bootloade at the beginning of flash memory
+void jump_to_bootloader(void);

projects/bootloader/inc/stm32f0xx/bootloader_mcu.h → libraries/ms-bootloader/inc/stm32f0xx/bootloader_mcu.h

@@ -4,8 +4,7 @@
 
 #include <stdint.h>
 
-// TODO(SOFT-416): Move this to ms-bootloader.
-
+#ifdef BOOTLOADER_APPLICATION
 // The addresses of these values are defined in the bootloader linker script (memory_spaces.ld).
 // If there's an undefined reference linker error from here, you're using the wrong linker script!
 extern uint32_t _config_page1_start;
@@ -15,6 +14,8 @@ extern uint32_t _application_size;
 extern uint32_t _ram_start;
 extern uint32_t _ram_size;
 extern uint32_t _vector_table_size;
+extern uint32_t _bootloader_start;
+extern uint32_t _bootloader_size;
 
 #define BOOTLOADER_CONFIG_PAGE_1_START ((void *)&_config_page1_start)
 #define BOOTLOADER_CONFIG_PAGE_2_START ((void *)&_config_page2_start)
@@ -23,3 +24,13 @@ extern uint32_t _vector_table_size;
 #define BOOTLOADER_RAM_START ((void *)&_ram_start)
 #define BOOTLOADER_RAM_SIZE ((size_t)&_ram_size)
 #define BOOTLOADER_VECTOR_TABLE_SIZE ((size_t)&_vector_table_size)
+#define BOOTLOADER_START ((void *)&_bootloader_start)
+#define BOOTLOADER_SIZE ((size_t)&_bootloader_size)
+#else
+// If we're not in the bootloader or the application, we shouldn't use this!
+#define BOOTLOADER_CONFIG_PAGE_1_START ((void *)0)
+#define BOOTLOADER_CONFIG_PAGE_2_START ((void *)0)
+#define BOOTLOADER_APPLICATION_START ((void *)0)
+#define BOOTLOADER_APPLICATION_SIZE (((size_t)0))
+#define BOOTLOADER_VECTOR_TABLE_SIZE ((size_t)0)
+#endif

libraries/ms-bootloader/rules.mk

@@ -0,0 +1,9 @@
+# Defines $(T)_SRC, $(T)_INC, $(T)_DEPS, and $(T)_CFLAGS for the build makefile.
+# Tests can be excluded by defining $(T)_EXCLUDE_TESTS.
+# Pre-defined:
+# $(T)_SRC_ROOT: $(T)_DIR/src
+# $(T)_INC_DIRS: $(T)_DIR/inc{/$(PLATFORM)}
+# $(T)_SRC: $(T)_DIR/src{/$(PLATFORM)}/*.{c,s}
+
+# Specify the libraries you want to include
+$(T)_DEPS := 

libraries/ms-bootloader/src/jump.c

@@ -0,0 +1,12 @@
+#include "jump.h"
+
+__attribute__((naked)) noreturn void prv_perform_jump(uint32_t sp, uint32_t pc) {
+  __asm(
+      "msr msp, %[sp] \n"  // reset the main stack pointer (msp) to sp
+      "bx %[pc] \n"        // jump to pc
+
+      // this bizarre syntax associates the "sp" and "pc" in asm with the sp and pc parameters
+      // see http://www.ethernut.de/en/documents/arm-inline-asm.html
+      :
+      : [sp] "r"(sp), [pc] "r"(pc));
+}

libraries/ms-bootloader/src/jump_to_bootloader.c

@@ -0,0 +1,32 @@
+#include "jump_to_bootloader.h"
+
+#include <stdint.h>
+#include <stdnoreturn.h>
+#include <string.h>
+
+#include "bootloader_mcu.h"
+#include "jump.h"
+#include "stm32f0xx_misc.h"
+#include "stm32f0xx_syscfg.h"
+
+void jump_to_bootloader(void) {
+#ifdef BOOTLOADER_APPLICATION // don't do anything if we're not in the bootloader/application
+  // Disable all interrupts so their is no interference when working with vector tables
+  __disable_irq();
+
+  // Reset the vector table to bootloader's vector table
+  SYSCFG_MemoryRemapConfig(
+      SYSCFG_MemoryRemap_Flash);  // change where the vector table is stored to beginning of flash
+
+  // story memory location of bootloader starting point at the beginning of flash?
+  uint32_t *bootloader_in_flash = BOOTLOADER_START;
+  // setting the stack pointer to the bootloader location now
+  uint32_t initial_sp = bootloader_in_flash[0];
+  uint32_t reset_handler_pc = bootloader_in_flash[1];
+
+  // re-enable interrupts
+  __enable_irq();
+  // jump to bootloader
+  perform_jump(initial_sp, reset_handler_pc);
+#endif // BOOTLOADER_APPLICATION
+}

libraries/ms-common/rules.mk

@@ -10,6 +10,8 @@ ifneq (,$(IS_MU))
 $(T)_DEPS += mu-gen mu-store
 endif
 
+$(T)_DEPS += ms-bootloader
+
 ifeq (x86,$(PLATFORM))
 $(T)_EXCLUDE_TESTS := pwm pwm_input
 $(T)_CFLAGS += -DX86

libraries/ms-common/src/can_fsm.c

@@ -1,9 +1,11 @@
 #include "can_fsm.h"
+
 #include "bootloader_can.h"
 #include "can.h"
 #include "can_hw.h"
 #include "can_msg_defs.h"
 #include "can_rx.h"
+#include "jump_to_bootloader.h"
 
 FSM_DECLARE_STATE(can_rx_fsm_handle);
 FSM_DECLARE_STATE(can_tx_fsm_handle);
@@ -57,6 +59,10 @@ static void prv_handle_rx(Fsm *fsm, const Event *e, void *context) {
 
   // Process bootloader messages
   if (rx_msg.source_id == SYSTEM_CAN_DEVICE_BOOTLOADER) {
+#ifdef BOOTLOADER_APPLICATION  // *NOTE: jump to bootloader does not actually return
+    jump_to_bootloader();
+    return;
+#endif
     result = bootloader_can_receive(&rx_msg);
     return;
   }

platform/stm32f0xx/platform.mk

@@ -44,6 +44,7 @@ endif
 DEFAULT_LINKER_SCRIPT ?= stm32f0_default.ld
 ifeq ($(MAKECMDGOALS),temp-bootloader-write)
 DEFAULT_LINKER_SCRIPT := stm32f0_application.ld
+CFLAGS += -DBOOTLOADER_APPLICATION
 endif
 
 # Device openocd config file

projects/bootloader/rules.mk

@@ -13,7 +13,7 @@ $(T)_SRC := $(wildcard $($(T)_SRC_ROOT)/src/*.c) \
 
 $(T)_INC_DIRS += $($(T)_DIR)/protogen
 
-$(T)_DEPS := ms-common ms-helper nanopb
+$(T)_DEPS := ms-common ms-helper nanopb ms-bootloader
 
 $(T)_LINKER_SCRIPT := stm32f0_bootloader.ld
 $(T)_test_config_MOCKS := persist_init

projects/bootloader/src/main.c

@@ -8,6 +8,7 @@
 #include "flash.h"
 #include "interrupt.h"
 #include "jump_to_application.h"
+#include "jump_to_bootloader.h"
 #include "log.h"
 #include "ping.h"
 #include "query.h"