1 files changed, 94 insertions, 0 deletions
diff --git a/platforms/chibios/bootloaders/stm32_dfu.c b/platforms/chibios/bootloaders/stm32_dfu.c
new file mode 100644
index 0000000000..0a113570f7
--- /dev/null
+++ b/platforms/chibios/bootloaders/stm32_dfu.c
@@ -0,0 +1,94 @@
+/* Copyright 2021 QMK
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program.  If not, see <http://www.gnu.org/licenses/>.
+ */
+
+#include "bootloader.h"
+
+#include <ch.h>
+#include <hal.h>
+#include "wait.h"
+
+extern uint32_t __ram0_end__;
+
+#ifndef STM32_BOOTLOADER_DUAL_BANK
+#    define STM32_BOOTLOADER_DUAL_BANK FALSE
+#endif
+
+#if STM32_BOOTLOADER_DUAL_BANK
+#    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
+
+__attribute__((weak)) 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();
+}
+
+// not needed at all, but if anybody attempts to invoke it....
+void enter_bootloader_mode_if_requested(void) {}
+
+#else
+
+/* This code should be checked whether it runs correctly on platforms */
+#    define SYMVAL(sym) (uint32_t)(((uint8_t *)&(sym)) - ((uint8_t *)0))
+#    define BOOTLOADER_MAGIC 0xDEADBEEF
+#    define MAGIC_ADDR (unsigned long *)(SYMVAL(__ram0_end__) - 4)
+
+__attribute__((weak)) void bootloader_jump(void) {
+    *MAGIC_ADDR = BOOTLOADER_MAGIC;  // set magic flag => reset handler will jump into boot loader
+    NVIC_SystemReset();
+}
+
+void enter_bootloader_mode_if_requested(void) {
+    unsigned long *check = MAGIC_ADDR;
+    if (*check == BOOTLOADER_MAGIC) {
+        *check = 0;
+        __set_CONTROL(0);
+        __set_MSP(*(__IO uint32_t *)STM32_BOOTLOADER_ADDRESS);
+        __enable_irq();
+
+        typedef void (*BootJump_t)(void);
+        BootJump_t boot_jump = *(BootJump_t *)(STM32_BOOTLOADER_ADDRESS + 4);
+        boot_jump();
+        while (1)
+            ;
+    }
+}
+#endif