CTRL keyboard bootloader_jump support

Adds support for CTRL keyboards to enter bootloader via bootloader_jump()

lib/arm_atsam/packs/atmel/SAMD51_DFP/1.0.70/gcc/gcc/samd51j18a_flash.ld

@@ -51,6 +51,9 @@ HEAP_SIZE = DEFINED(HEAP_SIZE) ? HEAP_SIZE : DEFINED(__heap_size__) ? __heap_siz
 _srom = ORIGIN(rom);
 _lrom = LENGTH(rom);
 _erom = ORIGIN(rom) + LENGTH(rom);
+_sram = ORIGIN(ram);
+_lram = LENGTH(ram);
+_eram = ORIGIN(ram) + LENGTH(ram);
 
 /* Section Definitions */
 SECTIONS

tmk_core/common/arm_atsam/bootloader.c

@@ -16,25 +16,27 @@
 
 #include "bootloader.h"
 #include "samd51j18a.h"
+#include "md_bootloader.h"
 
 //Set watchdog timer to reset. Directs the bootloader to stay in programming mode.
-void bootloader_jump(void)
-{
-    //Keyboards released with certain bootloader can not enter bootloader from app until workaround is created
-    uint8_t ver_no_jump[] = "v2.18Jun 22 2018 17:28:08";
-    uint8_t *ver_check = ver_no_jump;
-    uint8_t *boot_check = (uint8_t *)0x21A0;
-    while (*ver_check && *boot_check == *ver_check)
-    {
-        ver_check++;
-        boot_check++;
+void bootloader_jump(void) {
+#ifdef KEYBOARD_massdrop_ctrl
+    //CTRL keyboards released with bootloader version below must use RAM method. Otherwise use WDT method.
+    uint8_t ver_ram_method[] = "v2.18Jun 22 2018 17:28:08";     //The version to match (NULL terminated by compiler)
+    uint8_t *ver_check = ver_ram_method;                        //Pointer to version match string for traversal
+    uint8_t *ver_rom = (uint8_t *)0x21A0;                       //Pointer to address in ROM where this specific bootloader version would exist
+
+    while (*ver_check && *ver_rom == *ver_check) {              //While there are check version characters to match and bootloader's version matches check's version
+        ver_check++;                                            //Move check version pointer to next character
+        ver_rom++;                                              //Move ROM version pointer to next character
     }
-    if (!*ver_check)
-    {
-        //Version match
-        //Software workaround would go here
-        return; //No software restart method implemented... must use hardware reset button
+
+    if (!*ver_check) {                                          //If check version pointer is NULL, all characters have matched
+        *MAGIC_ADDR = BOOTLOADER_MAGIC;                         //Set magic number into RAM
+        NVIC_SystemReset();                                     //Perform system reset
+        while (1) {}                                            //Won't get here
     }
+#endif
 
     WDT->CTRLA.bit.ENABLE = 0;
     while (WDT->SYNCBUSY.bit.ENABLE) {}

tmk_core/protocol/arm_atsam/md_bootloader.h

@@ -7,6 +7,13 @@ extern uint32_t _erom;
 
 #define BOOTLOADER_SERIAL_MAX_SIZE 20   //DO NOT MODIFY!
 
+#ifdef KEYBOARD_massdrop_ctrl
+//WARNING: These are only for CTRL bootloader release "v2.18Jun 22 2018 17:28:08" for bootloader_jump support
+extern uint32_t _eram;
+#define BOOTLOADER_MAGIC 0x3B9ACA00
+#define MAGIC_ADDR (uint32_t *)(&_eram - 4)
+#endif
+
 #ifdef MD_BOOTLOADER
 
 #define MCU_HZ 48000000

tmk_core/protocol/arm_atsam/startup.c

@@ -28,6 +28,7 @@
  */
 
 #include "samd51.h"
+#include "md_bootloader.h"
 
 /* Initialize segments */
 extern uint32_t _sfixed;
@@ -500,6 +501,16 @@ const DeviceVectors exception_table = {
  */
 void Reset_Handler(void)
 {
+#ifdef KEYBOARD_massdrop_ctrl
+        /* WARNING: This is only for CTRL bootloader release "v2.18Jun 22 2018 17:28:08" for bootloader_jump support */
+        if (*MAGIC_ADDR == BOOTLOADER_MAGIC) {
+                /* At this point, the bootloader's memory is initialized properly, so undo the jump to here, then jump back */
+                *MAGIC_ADDR = 0x00000000;           /* Change value to prevent potential bootloader entrance loop */
+                __set_MSP(0x20008818);              /* MSP according to bootloader */
+                SCB->VTOR = 0x00000000;             /* Vector table back to bootloader's */
+                asm("bx %0"::"r"(0x00001267));      /* Jump past bootloader RCAUSE check using THUMB */
+        }
+#endif
         uint32_t *pSrc, *pDest;
 
         /* Initialize the relocate segment */