Soft 468 jumping back to bootloader by vaaranan-y · Pull Request #459 · uw-midsun/firmware_xiv

vaaranan-y · 2021-10-02T15:33:58Z

No description provided.

…s://github.com/uw-midsun/firmware_xiv into soft_468_jumping_back_to_bootloader

ryandancy

Looks pretty good, I'll test this in a bit, and I've left some action items in the comments.

ryandancy · 2021-10-02T17:20:46Z

+
+  // Reset the vector table to bootloader's vector table
+  SYSCFG_MemoryRemapConfig(
+      SYSCFG_MemoryRemap_SRAM);  // change where the vector table is stored to beginning of flash


This will set the vector table to the beginning of SRAM (which is where it is already since we're in the application) - you'll need to use SYSCFG_MemoryRemap_Flash instead (see stm32f0xx_syscfg.h).

ryandancy · 2021-10-02T17:24:48Z

+static noreturn __attribute__((naked)) 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));
+}


We might want to factor this function out from this and jump_to_application.c into an ms-common (or ms-bootloader) library called jump.h since it just jumps to a particular location.

ryandancy · 2021-10-02T17:55:35Z

 #include "flash.h"
 #include "interrupt.h"
 #include "jump_to_application.h"
+#include "jump_to_bootloader.h"


So the next steps for this module is that we want to jump from the bootloader to the application when we receive a datagram message while in an application. This will be in can_fsm.c, in the if (rx_msg.source_id == SYSTEM_CAN_DEVICE_BOOTLOADER) if statement. Essentially, when that if statement is reached:

if we're in an application running on the bootloader, in which case we should jump to the bootloader so that the bootloader can receive subsequent datagram messages

oherwise, we should call bootloader_can_receive there like we do now so that the bootloader can process the message (if necessary)

So there are a couple of parts to doing this:

We'll need to move jump_to_bootloader to a library, perhaps called ms-bootloader, so can_fsm.c can reach it. Perhaps move bootloader_mcu.h to that library too.

We'll need a way to determine which of the three scenarios above we're in. This is a bit tricky: we'll need a preprocessor symbol that's defined when we're compiling for an application running on the bootloader. You can do this by adding a -D<symbolname> argument to the C compiler flags when compiling for the application, which currently you can do in platform/stm32f0xx/platform.mk by adding CFLAGS += -D<symbolname> to the ifeq ($(MAKECMDGOALS),temp-bootloader-write) if statement (replace <symbolname> with the symbol you want defined when on the application only). Then you can test with #ifdef in can_fsm.c.

…pps on bootloader

…s://github.com/uw-midsun/firmware_xiv into soft_468_jumping_back_to_bootloader

ryandancy · 2021-11-13T03:03:30Z

 #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_DEFAULT_LOCATION ((void *)&_bootloader_start)


I think BOOTLOADER_START might be a clearer name for this, especially since we'll likely never have the bootloader at a different location (so not "default").

ryandancy · 2021-11-13T03:05:56Z

@@ -0,0 +1,30 @@
+#include "jump_to_bootloader.h"


jump_to_application, jump_to_bootloader, and jump shouldn't be duplicated between the bootloader project and the ms-bootloader libraries, they should only appear in ms-bootloader. So remove the copies in the bootloader project / move all the functionality to ms-bootloader.

ryandancy · 2021-11-13T03:07:31Z

 DEFAULT_LINKER_SCRIPT ?= stm32f0_default.ld
 ifeq ($(MAKECMDGOALS),temp-bootloader-write)
 DEFAULT_LINKER_SCRIPT := stm32f0_application.ld
+CFLAGS += -DAPP_COMP_ON_BOOT


What does APP_COMP_ON_BOOT stand for? BOOTLOADER_APPLICATION might be clearer.

ryandancy · 2021-11-13T03:13:07Z

@@ -0,0 +1,12 @@
+#include "jump.h"
+
+noreturn void prv_perform_jump(uint32_t sp, uint32_t pc) {


You'll need to add back the __attribute__((naked)) here - it tells the compiler not to generate the standard entry/exit code for functions and just to use the raw assembly. It also will stop CI from complaining about noreturn.

Also, this is STM32-specific - you'll need to move it to an stm32f0xx folder and add a (no-op) x86 implementation.

ryandancy · 2021-11-13T03:13:36Z

+        - 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


You should write a brief description of what goes in ms-bootloader here.

…s://github.com/uw-midsun/firmware_xiv into soft_468_jumping_back_to_bootloader

ryandancy

Looks good (barring tiny changes)! I'll approve once you validate it onsite :)

The big thing to validate is if we can successful jump back to the bootloader from an application a) on demand (i.e. using a test project) and b) when we receive a bootloader CAN message. Use make temp-bootloader-write as described in #476 to flash (you'll need that PR on your branch). Mitchell can show you how to use cansend to send a bootloader CAN message manually.

ryandancy · 2021-11-16T02:46:56Z

+<!--
+    ms-bootloader currently contains the jump_to_bootloader project, which allows an application to jump back to the bootloader on command
+>


Don't comment it out!  is the syntax for a comment in Markdown (and also HTML), just write it in plain text.

ryandancy · 2021-11-16T02:51:41Z

  // Process bootloader messages
  if (rx_msg.source_id == SYSTEM_CAN_DEVICE_BOOTLOADER) {
+#ifdef APP_COMP_ON_BOOT
+    jump_to_bootloader();


Nitpick: you'll want to add a comment saying that jump_to_bootloader doesn't return since that's important for anyone reading the code. You also might want to add a return; afterwards even though it technically doesn't do anything, just so it doesn't read like you're then going to call bootloader_can_receive.

ryandancy · 2021-11-16T02:52:42Z


  // Process bootloader messages
  if (rx_msg.source_id == SYSTEM_CAN_DEVICE_BOOTLOADER) {
+#ifdef APP_COMP_ON_BOOT


You'll need to change this to BOOTLOADER_APPLICATION too.

ryandancy · 2021-11-16T02:53:51Z

 #include "can_hw.h"
 #include "can_msg_defs.h"
 #include "can_rx.h"
+#include "jump_to_bootloader.h"


You'll get a linker error here when the jump_to_bootloader call actually gets compiled - you'll need to add ms-bootloader to the $(T)_DEPS list in ms-common's rules.mk to tell the build system to link the ms-bootloader object files along with the ms-common ones.

ryandancy · 2021-11-16T02:54:33Z

@@ -0,0 +1,8 @@
+#pragma once
+


Nitpick: add a comment here saying what the library is used for, i.e. it lets you jump to an arbitrary memory address.

vaaranan-y and others added 7 commits August 25, 2021 21:28

Replaced old NTC curve with new experimental curve

cab2401

modified appropriate test(s)

f1ce7d0

implemented jump to bootloader, follow comments

6d48397

updated main in bootloader

b0a8848

Fixed macro typecast error

069f19b

Merge branch 'master' into soft_468_jumping_back_to_bootloader

d52dd55

[SOFT-468] Merge branch 'soft_468_jumping_back_to_bootloader' of http…

2f6df6a

…s://github.com/uw-midsun/firmware_xiv into soft_468_jumping_back_to_bootloader

vaaranan-y requested a review from ryandancy October 2, 2021 16:31

ryandancy suggested changes Oct 2, 2021

View reviewed changes

vaaranan-y and others added 17 commits October 9, 2021 04:11

[SOFT-468] Fixed memory configuration to flash, not SRAM

d7782c6

[SOFT-468] Modularized jump function

4ec7d10

[SOFT-468] Added ms-bootloader library

8b21f0d

[SOFT-468] Implemented preprocessorconditional upon compilation for a…

0687368

…pps on bootloader

[SOFT-468] fixed jump function implementation

b582454

Merge branch 'master' into soft_468_jumping_back_to_bootloader

3be0a3a

[SOFT-468] moved jump.c

a91053c

[SOFT-468] made perform_jump non-static/public

3837dd3

[SOFT-468] fixing merge issues

adf3c2c

[SOFT-468] included string library to jump header

718f7f8

[SOFT-468] Removed naked attribute from jump function

d3d5bd5

Merge branch 'master' into soft_468_jumping_back_to_bootloader

8289d59

[SOFT-468] Removed naked attribute from jump function in project itself

ad43709

[SOFT-468] Merge branch 'soft_468_jumping_back_to_bootloader' of http…

6b5dbae

…s://github.com/uw-midsun/firmware_xiv into soft_468_jumping_back_to_bootloader

[SOFT-468] Moved implementation to STM32F0XX

f3a9b4b

[SOFT-468] removed noreturn from perform jump

4be0005

Merge branch 'master' into soft_468_jumping_back_to_bootloader

b502b92

ryandancy suggested changes Nov 13, 2021

View reviewed changes

vaaranan-y added 3 commits November 13, 2021 17:41

[SOFT-468] moved implementation from bootloader project to ms-bootloader

f379df3

[SOFT-468] changes APP_COMP_ON_BOOT to BOOTLOADER_APPLICATION

450b243

[SOFT-468] changed BOOTLOADER_DEFAULT_LOCATION to BOOTLOADER_START

426d9e3

vaaranan-y added 2 commits November 13, 2021 17:51

[SOFT-468] Added description for ms-bootloader

d75fa56

[SOFT-468] Merge branch 'soft_468_jumping_back_to_bootloader' of http…

eaf6cd0

…s://github.com/uw-midsun/firmware_xiv into soft_468_jumping_back_to_bootloader

vaaranan-y requested a review from ryandancy November 13, 2021 18:42

ryandancy suggested changes Nov 16, 2021

View reviewed changes

vaaranan-y and others added 4 commits January 21, 2022 23:57

Merge branch 'master' into soft_468_jumping_back_to_bootloader

3a84088

[SOFT-468] changed APP_ON_COMP to BOOTLOADER_APPLICATION

47f14b9

[SOFT-468] merged

fa7f236

[SOFT-468] Fix bootloader_mcu include issues

f0c9869

		@@ -0,0 +1,12 @@
		#include "jump.h"

		noreturn void prv_perform_jump(uint32_t sp, uint32_t pc) {

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