1 files changed, 56 insertions, 18 deletions

diff --git a/tmk_core/common/chibios/bootloader.c b/tmk_core/common/chibios/bootloader.c
index 4cf5dae7e6..7b2cf5c435 100644
--- a/tmk_core/common/chibios/bootloader.c
+++ b/tmk_core/common/chibios/bootloader.c
@@ -2,29 +2,67 @@
 
 #include "ch.h"
 #include "hal.h"
-
-#ifdef STM32_BOOTLOADER_ADDRESS
-/* STM32 */
+#include "wait.h"
 
 /* This code should be checked whether it runs correctly on platforms */
-#    define SYMVAL(sym) (uint32_t)(((uint8_t *)&(sym)) - ((uint8_t *)0))
+#define SYMVAL(sym) (uint32_t)(((uint8_t *)&(sym)) - ((uint8_t *)0))
+#define BOOTLOADER_MAGIC 0xDEADBEEF
+#define MAGIC_ADDR (unsigned long *)(SYMVAL(__ram0_end__) - 4)
+
+#ifndef STM32_BOOTLOADER_DUAL_BANK
+#    define STM32_BOOTLOADER_DUAL_BANK FALSE
+#endif
+
+#if STM32_BOOTLOADER_DUAL_BANK
+
+// Need pin definitions
+#    include "config_common.h"
+
+#    ifndef STM32_BOOTLOADER_DUAL_BANK_GPIO
+#        error "No STM32_BOOTLOADER_DUAL_BANK_GPIO defined, don't know which pin to toggle"
+#    endif
+
+#    ifndef STM32_BOOTLOADER_DUAL_BANK_POLARITY
+#        define STM32_BOOTLOADER_DUAL_BANK_POLARITY 0
+#    endif
+
+#    ifndef STM32_BOOTLOADER_DUAL_BANK_DELAY
+#        define STM32_BOOTLOADER_DUAL_BANK_DELAY 100000
+#    endif
+
+extern uint32_t __ram0_end__;
+
+void bootloader_jump(void) {
+    // For STM32 MCUs with dual-bank flash, and we're incapable of jumping to the bootloader. The first valid flash
+    // bank is executed unconditionally after a reset, so it doesn't enter DFU unless BOOT0 is high. Instead, we do
+    // it with hardware...in this case, we pull a GPIO high/low depending on the configuration, connects 3.3V to
+    // BOOT0's RC charging circuit, lets it charge the capacitor, and issue a system reset. See the QMK discord
+    // #hardware channel pins for an example circuit.
+    palSetPadMode(PAL_PORT(STM32_BOOTLOADER_DUAL_BANK_GPIO), PAL_PAD(STM32_BOOTLOADER_DUAL_BANK_GPIO), PAL_MODE_OUTPUT_PUSHPULL);
+#    if STM32_BOOTLOADER_DUAL_BANK_POLARITY
+    palSetPad(PAL_PORT(STM32_BOOTLOADER_DUAL_BANK_GPIO), PAL_PAD(STM32_BOOTLOADER_DUAL_BANK_GPIO));
+#    else
+    palClearPad(PAL_PORT(STM32_BOOTLOADER_DUAL_BANK_GPIO), PAL_PAD(STM32_BOOTLOADER_DUAL_BANK_GPIO));
+#    endif
+
+    // Wait for a while for the capacitor to charge
+    wait_ms(100);
+
+    // Issue a system reset to get the ROM bootloader to execute, with BOOT0 high
+    NVIC_SystemReset();
+}
+
+void enter_bootloader_mode_if_requested(void) {}  // not needed at all, but if anybody attempts to invoke it....
+
+#elif defined(STM32_BOOTLOADER_ADDRESS)  // STM32_BOOTLOADER_DUAL_BANK
+
 extern uint32_t __ram0_end__;
-#    define BOOTLOADER_MAGIC 0xDEADBEEF
-#    define MAGIC_ADDR (unsigned long *)(SYMVAL(__ram0_end__) - 4)
 
-/** \brief Jump to the bootloader
- *
- * FIXME: needs doc
- */
 void bootloader_jump(void) {
     *MAGIC_ADDR = BOOTLOADER_MAGIC;  // set magic flag => reset handler will jump into boot loader
     NVIC_SystemReset();
 }
 
-/** \brief Enter bootloader mode if requested
- *
- * FIXME: needs doc
- */
 void enter_bootloader_mode_if_requested(void) {
     unsigned long *check = MAGIC_ADDR;
     if (*check == BOOTLOADER_MAGIC) {
@@ -41,10 +79,10 @@ void enter_bootloader_mode_if_requested(void) {
     }
 }
 
-#elif defined(KL2x) || defined(K20x) /* STM32_BOOTLOADER_ADDRESS */
+#elif defined(KL2x) || defined(K20x)  // STM32_BOOTLOADER_DUAL_BANK // STM32_BOOTLOADER_ADDRESS
 /* Kinetis */
 
-#    if defined(KIIBOHD_BOOTLOADER)
+#    if defined(BOOTLOADER_KIIBOHD)
 /* Kiibohd Bootloader (MCHCK and Infinity KB) */
 #        define SCB_AIRCR_VECTKEY_WRITEMAGIC 0x05FA0000
 const uint8_t sys_reset_to_loader_magic[] = "\xff\x00\x7fRESET TO LOADER\x7f\x00\xff";
@@ -54,14 +92,14 @@ void          bootloader_jump(void) {
     SCB->AIRCR = SCB_AIRCR_VECTKEY_WRITEMAGIC | SCB_AIRCR_SYSRESETREQ_Msk;
 }
 
-#    else /* defined(KIIBOHD_BOOTLOADER) */
+#    else /* defined(BOOTLOADER_KIIBOHD) */
 /* Default for Kinetis - expecting an ARM Teensy */
 #        include "wait.h"
 void bootloader_jump(void) {
     wait_ms(100);
     __BKPT(0);
 }
-#    endif /* defined(KIIBOHD_BOOTLOADER) */
+#    endif /* defined(BOOTLOADER_KIIBOHD) */
 
 #else /* neither STM32 nor KINETIS */
 __attribute__((weak)) void bootloader_jump(void) {}