Add mmoskal/uf2-stm32f103 bootloader support (#19594)

4 files changed, 118 insertions, 0 deletions

diff --git a/platforms/chibios/boards/common/ld/STM32F103xB_uf2boot.ld b/platforms/chibios/boards/common/ld/STM32F103xB_uf2boot.ld
new file mode 100644
index 0000000000..98d0f3ea75
--- /dev/null
+++ b/platforms/chibios/boards/common/ld/STM32F103xB_uf2boot.ld
@@ -0,0 +1,88 @@
+/*
+    ChibiOS - Copyright (C) 2006..2018 Giovanni Di Sirio
+
+    Licensed under the Apache License, Version 2.0 (the "License");
+    you may not use this file except in compliance with the License.
+    You may obtain a copy of the License at
+
+        http://www.apache.org/licenses/LICENSE-2.0
+
+    Unless required by applicable law or agreed to in writing, software
+    distributed under the License is distributed on an "AS IS" BASIS,
+    WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+    See the License for the specific language governing permissions and
+    limitations under the License.
+*/
+
+/*
+ * ST32F103xB memory setup.
+ */
+MEMORY
+{
+    flash0 (rx) : org = 0x08000000 + 16K, len = 128k - 16K
+    flash1 (rx) : org = 0x00000000, len = 0
+    flash2 (rx) : org = 0x00000000, len = 0
+    flash3 (rx) : org = 0x00000000, len = 0
+    flash4 (rx) : org = 0x00000000, len = 0
+    flash5 (rx) : org = 0x00000000, len = 0
+    flash6 (rx) : org = 0x00000000, len = 0
+    flash7 (rx) : org = 0x00000000, len = 0
+    ram0   (wx) : org = 0x20000000, len = 20k
+    ram1   (wx) : org = 0x00000000, len = 0
+    ram2   (wx) : org = 0x00000000, len = 0
+    ram3   (wx) : org = 0x00000000, len = 0
+    ram4   (wx) : org = 0x00000000, len = 0
+    ram5   (wx) : org = 0x00000000, len = 0
+    ram6   (wx) : org = 0x00000000, len = 0
+    ram7   (wx) : org = 0x00000000, len = 0
+}
+
+/* For each data/text section two region are defined, a virtual region
+   and a load region (_LMA suffix).*/
+
+/* Flash region to be used for exception vectors.*/
+REGION_ALIAS("VECTORS_FLASH", flash0);
+REGION_ALIAS("VECTORS_FLASH_LMA", flash0);
+
+/* Flash region to be used for constructors and destructors.*/
+REGION_ALIAS("XTORS_FLASH", flash0);
+REGION_ALIAS("XTORS_FLASH_LMA", flash0);
+
+/* Flash region to be used for code text.*/
+REGION_ALIAS("TEXT_FLASH", flash0);
+REGION_ALIAS("TEXT_FLASH_LMA", flash0);
+
+/* Flash region to be used for read only data.*/
+REGION_ALIAS("RODATA_FLASH", flash0);
+REGION_ALIAS("RODATA_FLASH_LMA", flash0);
+
+/* Flash region to be used for various.*/
+REGION_ALIAS("VARIOUS_FLASH", flash0);
+REGION_ALIAS("VARIOUS_FLASH_LMA", flash0);
+
+/* Flash region to be used for RAM(n) initialization data.*/
+REGION_ALIAS("RAM_INIT_FLASH_LMA", flash0);
+
+/* RAM region to be used for Main stack. This stack accommodates the processing
+   of all exceptions and interrupts.*/
+REGION_ALIAS("MAIN_STACK_RAM", ram0);
+
+/* RAM region to be used for the process stack. This is the stack used by
+   the main() function.*/
+REGION_ALIAS("PROCESS_STACK_RAM", ram0);
+
+/* RAM region to be used for data segment.*/
+REGION_ALIAS("DATA_RAM", ram0);
+REGION_ALIAS("DATA_RAM_LMA", flash0);
+
+/* RAM region to be used for BSS segment.*/
+REGION_ALIAS("BSS_RAM", ram0);
+
+/* RAM region to be used for the default heap.*/
+REGION_ALIAS("HEAP_RAM", ram0);
+
+/* Generic rules inclusion.*/
+INCLUDE rules.ld
+
+/* Bootloader reset support */
+_board_magic_reg = ORIGIN(ram0) + 16k; /* this is based off the code within backup.c */
diff --git a/platforms/chibios/bootloader.mk b/platforms/chibios/bootloader.mk
index 0568d35321..85f1866062 100644
--- a/platforms/chibios/bootloader.mk
+++ b/platforms/chibios/bootloader.mk
@@ -104,6 +104,11 @@ ifeq ($(strip $(BOOTLOADER)), tinyuf2)
     BOOTLOADER_TYPE = tinyuf2
     FIRMWARE_FORMAT = uf2
 endif
+ifeq ($(strip $(BOOTLOADER)), uf2boot)
+    OPT_DEFS += -DBOOTLOADER_UF2BOOT
+    BOOTLOADER_TYPE = uf2boot
+    FIRMWARE_FORMAT = uf2
+endif
 ifeq ($(strip $(BOOTLOADER)), rp2040)
     OPT_DEFS += -DBOOTLOADER_RP2040
     BOOTLOADER_TYPE = rp2040
diff --git a/platforms/chibios/bootloaders/uf2boot.c b/platforms/chibios/bootloaders/uf2boot.c
new file mode 100644
index 0000000000..f5b1a64334
--- /dev/null
+++ b/platforms/chibios/bootloaders/uf2boot.c
@@ -0,0 +1,23 @@
+// Copyright 2023 QMK
+// SPDX-License-Identifier: GPL-2.0-or-later
+
+#include "bootloader.h"
+
+// From mmoskal/uf2-stm32f103's backup.c
+#define MAGIC_BOOT 0x544F4F42UL
+
+// defined by linker script
+extern uint32_t _board_magic_reg[];
+#define MAGIC_REG _board_magic_reg[0]
+
+void bootloader_jump(void) {
+    MAGIC_REG = MAGIC_BOOT;
+    NVIC_SystemReset();
+}
+
+void mcu_reset(void) {
+    NVIC_SystemReset();
+}
+
+/* not needed, no two-stage reset */
+void enter_bootloader_mode_if_requested(void) {}
diff --git a/platforms/chibios/flash.mk b/platforms/chibios/flash.mk
index 6e23d96e1c..ac842e8d62 100644
--- a/platforms/chibios/flash.mk
+++ b/platforms/chibios/flash.mk
@@ -109,6 +109,8 @@ else ifeq ($(strip $(BOOTLOADER)),kiibohd)
 	$(UNSYNC_OUTPUT_CMD) && $(call EXEC_DFU_UTIL)
 else ifeq ($(strip $(BOOTLOADER)),tinyuf2)
 	$(UNSYNC_OUTPUT_CMD) && $(call EXEC_UF2_UTIL_DEPLOY)
+else ifeq ($(strip $(BOOTLOADER)),uf2boot)
+	$(UNSYNC_OUTPUT_CMD) && $(call EXEC_UF2_UTIL_DEPLOY)
 else ifeq ($(strip $(BOOTLOADER)),rp2040)
 	$(UNSYNC_OUTPUT_CMD) && $(call EXEC_UF2_UTIL_DEPLOY)
 else ifeq ($(strip $(MCU_FAMILY)),KINETIS)