From 82a94ea1bd4d930aebb15f7a3316836a0488421d Mon Sep 17 00:00:00 2001
From: Joel Challis <git@zvecr.com>
Date: Wed, 18 Jan 2023 22:36:58 +0000
Subject: [PATCH] Add f303 to tinyuf2 bootloader support (#19620)

---
 builddefs/mcu_selection.mk                    |  6 +-
 docs/flashing.md                              |  4 +-
 .../boards/common/ld/STM32F303xC_tinyuf2.ld   | 88 +++++++++++++++++++
 3 files changed, 95 insertions(+), 3 deletions(-)
 create mode 100644 platforms/chibios/boards/common/ld/STM32F303xC_tinyuf2.ld

diff --git a/builddefs/mcu_selection.mk b/builddefs/mcu_selection.mk
index b566b1b5ac..1d05902fab 100644
--- a/builddefs/mcu_selection.mk
+++ b/builddefs/mcu_selection.mk
@@ -313,7 +313,11 @@ ifneq ($(findstring STM32F303, $(MCU)),)
   # Linker script to use
   # - it should exist either in <chibios>/os/common/startup/ARMCMx/compilers/GCC/ld/
   #   or <keyboard_dir>/ld/
-  MCU_LDSCRIPT ?= STM32F303xC
+  ifeq ($(strip $(BOOTLOADER)), tinyuf2)
+    MCU_LDSCRIPT ?= STM32F303xC_tinyuf2
+  else
+    MCU_LDSCRIPT ?= STM32F303xC
+  endif
 
   # Startup code to use
   #  - it should exist in <chibios>/os/common/startup/ARMCMx/compilers/GCC/mk/
diff --git a/docs/flashing.md b/docs/flashing.md
index a636f19c72..443fa3123e 100644
--- a/docs/flashing.md
+++ b/docs/flashing.md
@@ -324,7 +324,7 @@ Flashing sequence:
 
 ## tinyuf2
 
-Keyboards may opt into supporting the tinyuf2 bootloader. This is currently only supported on the F401/F411 blackpill.
+Keyboards may opt into supporting the tinyuf2 bootloader. This is currently only supported on F303/F401/F411.
 
 The `rules.mk` setting for this bootloader is `tinyuf2`, and can be specified at the keymap or user level.
 
@@ -365,7 +365,7 @@ CLI Flashing sequence:
 
 ## uf2boot
 
-Keyboards may opt into supporting the uf2boot bootloader. This is currently only supported on the F103 bluepill.
+Keyboards may opt into supporting the uf2boot bootloader. This is currently only supported on F103.
 
 The `rules.mk` setting for this bootloader is `uf2boot`, and can be specified at the keymap or user level.
 
diff --git a/platforms/chibios/boards/common/ld/STM32F303xC_tinyuf2.ld b/platforms/chibios/boards/common/ld/STM32F303xC_tinyuf2.ld
new file mode 100644
index 0000000000..809c53cba4
--- /dev/null
+++ b/platforms/chibios/boards/common/ld/STM32F303xC_tinyuf2.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.
+*/
+
+/*
+ * STM32F303xC memory setup.
+ */
+MEMORY
+{
+    flash0 (rx) : org = 0x08000000 + 16k, len = 256k - 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 = 40k
+    ram1   (wx) : org = 0x00000000, len = 0
+    ram2   (wx) : org = 0x00000000, len = 0
+    ram3   (wx) : org = 0x00000000, len = 0
+    ram4   (wx) : org = 0x10000000, len = 8k
+    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
+
+/* TinyUF2 bootloader reset support */
+_board_dfu_dbl_tap = ORIGIN(ram0) + 40k - 4; /* this is based off the linker file for tinyuf2 */