From d057e5157ed22508ce87f8fef113be52674ba209 Mon Sep 17 00:00:00 2001
From: flabbergast <s3+flabbergast@sdfeu.org>
Date: Tue, 8 Sep 2015 16:07:34 +0100
Subject: [PATCH] Implement jump-to-bootloader.

---
 tmk_core/common/chibios/bootloader.c          |  15 ++-
 .../tool/chibios/ch-bootloader-jump.patch     | 115 ++++++++++++++++++
 tmk_core/tool/chibios/common.mk               |   4 +
 3 files changed, 131 insertions(+), 3 deletions(-)
 create mode 100644 tmk_core/tool/chibios/ch-bootloader-jump.patch

diff --git a/tmk_core/common/chibios/bootloader.c b/tmk_core/common/chibios/bootloader.c
index 6c34e2e0..93f2e378 100644
--- a/tmk_core/common/chibios/bootloader.c
+++ b/tmk_core/common/chibios/bootloader.c
@@ -1,7 +1,16 @@
-/* TODO */
-/* ... chip dependent ... */
-
 #include "bootloader.h"
 
+#include "ch.h"
 
+#ifdef BOOTLOADER_ADDRESS
+#define SYMVAL(sym) (uint32_t)(((uint8_t *)&(sym)) - ((uint8_t *)0))
+extern uint32_t __ram0_end__;
+
+void bootloader_jump(void) {
+  *((unsigned long *)(SYMVAL(__ram0_end__) - 4)) = 0xDEADBEEF; // set magic flag => reset handler will jump into boot loader
+   NVIC_SystemReset();
+}
+#else /* BOOTLOADER_ADDRESS */
 void bootloader_jump(void) {}
+#endif /* BOOTLOADER_ADDRESS */
+
diff --git a/tmk_core/tool/chibios/ch-bootloader-jump.patch b/tmk_core/tool/chibios/ch-bootloader-jump.patch
new file mode 100644
index 00000000..7f33e8ac
--- /dev/null
+++ b/tmk_core/tool/chibios/ch-bootloader-jump.patch
@@ -0,0 +1,115 @@
+diff --git a/os/common/ports/ARMCMx/compilers/GCC/crt0_v6m.s b/os/common/ports/ARMCMx/compilers/GCC/crt0_v6m.s
+index 38b4513..12a3f39 100644
+--- a/os/common/ports/ARMCMx/compilers/GCC/crt0_v6m.s
++++ b/os/common/ports/ARMCMx/compilers/GCC/crt0_v6m.s
+@@ -98,6 +98,13 @@
+ #define CRT0_CALL_DESTRUCTORS               TRUE
+ #endif
+ 
++/**
++ * @brief   Magic number for jumping to bootloader.
++ */
++#if !defined(MAGIC_BOOTLOADER_NUMBER) || defined(__DOXYGEN__)
++#define MAGIC_BOOTLOADER_NUMBER 0xDEADBEEF
++#endif
++
+ /*===========================================================================*/
+ /* Code section.                                                             */
+ /*===========================================================================*/
+@@ -117,6 +124,17 @@
+                 .thumb_func
+                 .global Reset_Handler
+ Reset_Handler:
++
++#ifdef BOOTLOADER_ADDRESS
++                /* jump to bootloader code */
++                ldr        r0, =__ram0_end__-4
++                ldr        r1, =MAGIC_BOOTLOADER_NUMBER
++                ldr        r2, [r0, #0]
++                str        r0, [r0, #0] /* erase stored magic */
++                cmp        r2, r1
++                beq        Bootloader_Jump
++#endif /* BOOTLOADER_ADDRESS */
++
+                 /* Interrupts are globally masked initially.*/
+                 cpsid   i
+ 
+@@ -230,6 +248,21 @@ endfiniloop:
+                 ldr     r1, =__default_exit
+                 bx      r1
+ 
++#ifdef BOOTLOADER_ADDRESS
++/*
++ * Jump-to-bootloader function.
++ */
++
++                .align  2
++                .thumb_func
++Bootloader_Jump:
++                ldr     r0, =BOOTLOADER_ADDRESS
++                ldr     r1, [r0, #0]
++                mov     sp, r1
++                ldr     r0, [r0, #4]
++                bx      r0
++#endif /* BOOTLOADER_ADDRESS */
++
+ #endif
+ 
+ /** @} */
+diff --git a/os/common/ports/ARMCMx/compilers/GCC/crt0_v7m.s b/os/common/ports/ARMCMx/compilers/GCC/crt0_v7m.s
+index fcfa4de..2d560da 100644
+--- a/os/common/ports/ARMCMx/compilers/GCC/crt0_v7m.s
++++ b/os/common/ports/ARMCMx/compilers/GCC/crt0_v7m.s
+@@ -133,6 +133,13 @@
+ #define CRT0_CPACR_INIT                     0x00F00000
+ #endif
+ 
++/**
++ * @brief   Magic number for jumping to bootloader.
++ */
++#if !defined(MAGIC_BOOTLOADER_NUMBER) || defined(__DOXYGEN__)
++#define MAGIC_BOOTLOADER_NUMBER 0xDEADBEEF
++#endif
++
+ /*===========================================================================*/
+ /* Code section.                                                             */
+ /*===========================================================================*/
+@@ -157,6 +164,16 @@
+                 .thumb_func
+                 .global Reset_Handler
+ Reset_Handler:
++#ifdef BOOTLOADER_ADDRESS
++                /* jump to bootloader code */
++                ldr        r0, =__ram0_end__-4
++                ldr        r1, =MAGIC_BOOTLOADER_NUMBER
++                ldr        r2, [r0, #0]
++                str        r0, [r0, #0] /* erase stored magic */
++                cmp        r2, r1
++                beq        Bootloader_Jump
++#endif /* BOOTLOADER_ADDRESS */
++
+                 /* Interrupts are globally masked initially.*/
+                 cpsid   i
+ 
+@@ -289,6 +306,21 @@ endfiniloop:
+                 /* Branching to the defined exit handler.*/
+                 b       __default_exit
+ 
++#ifdef BOOTLOADER_ADDRESS
++/*
++ * Jump-to-bootloader function.
++ */
++
++                .align  2
++                .thumb_func
++Bootloader_Jump:
++                ldr     r0, =BOOTLOADER_ADDRESS
++                ldr     r1, [r0, #0]
++                mov     sp, r1
++                ldr     r0, [r0, #4]
++                bx      r0
++#endif /* BOOTLOADER_ADDRESS */
++
+ #endif /* !defined(__DOXYGEN__) */
+ 
+ /** @} */
diff --git a/tmk_core/tool/chibios/common.mk b/tmk_core/tool/chibios/common.mk
index 952ec493..0e9935dc 100644
--- a/tmk_core/tool/chibios/common.mk
+++ b/tmk_core/tool/chibios/common.mk
@@ -81,6 +81,10 @@ endif
 # Version string
 OPT_DEFS += -DVERSION=$(shell (git describe --always --dirty || echo 'unknown') 2> /dev/null)
 
+# Bootloader address
+ifdef BOOTLOADER_ADDRESS
+    OPT_DEFS += -DBOOTLOADER_ADDRESS=$(BOOTLOADER_ADDRESS)
+endif
 
 # Search Path
 VPATH += $(TMK_DIR)/common