From 237ca864da1bde97969bb887362a2d5431e1c10b Mon Sep 17 00:00:00 2001
From: Martin Mares <mj@ucw.cz>
Date: Mon, 17 Feb 2020 21:48:46 +0100
Subject: [PATCH] Programming using serial boot loader

---
 bin/stm32flash      |  3 +++
 mk/bluepill.mk      | 17 ++++++++++++++++-
 test-blink/Makefile |  5 +++--
 test-blink/test.c   |  3 +++
 4 files changed, 25 insertions(+), 3 deletions(-)
 create mode 100755 bin/stm32flash

diff --git a/bin/stm32flash b/bin/stm32flash
new file mode 100755
index 0000000..d660f9c
--- /dev/null
+++ b/bin/stm32flash
@@ -0,0 +1,3 @@
+#!/bin/sh
+# Flashing via serial boot loader
+exec ~/stm/stm32flash/stm32flash "$@"
diff --git a/mk/bluepill.mk b/mk/bluepill.mk
index d6146ab..e762525 100644
--- a/mk/bluepill.mk
+++ b/mk/bluepill.mk
@@ -105,15 +105,30 @@ ifdef WITH_DFU_FLASH
 
 else
 
+ifdef WITH_SERIAL_FLASH
+
+BOOT_SERIAL ?= /dev/ttyUSB0
+
 %.flash: %.bin
 	@printf "  FLASH  $<\n"
-	$(Q)$(ROOT)/bin/st-flash write $(*).bin 0x8000000
+	$(Q)$(ROOT)/bin/stm32flash $(BOOT_SERIAL) -i 'dtr,-dtr' -w $< -g 0
 
 .PHONY: reset
 reset: all
+	$(Q)$(ROOT)/bin/stm32flash $(BOOT_SERIAL) -i 'dtr,-dtr' -g 0
+
+else
+
+%.flash: %.bin
+	@printf "  FLASH  $<\n"
+	$(Q)$(ROOT)/bin/st-flash write $(*).bin 0x8000000
+
+.PHONY: reset
+reset:
 	$(ROOT)/bin/st-flash reset
 
 endif
+endif
 
 .SECONDEXPANSION:
 .SECONDARY:
diff --git a/test-blink/Makefile b/test-blink/Makefile
index 81ed48b..953160a 100644
--- a/test-blink/Makefile
+++ b/test-blink/Makefile
@@ -3,7 +3,8 @@ BINARY=test
 OBJS=test.o
 LIB_OBJS=util-debug.o
 
-WITH_BOOT_LOADER=1
-WITH_DFU_FLASH=1
+# WITH_BOOT_LOADER=1
+# WITH_DFU_FLASH=1
+WITH_SERIAL_FLASH=1
 
 include $(ROOT)/mk/bluepill.mk
diff --git a/test-blink/test.c b/test-blink/test.c
index 50ca8ba..e56426c 100644
--- a/test-blink/test.c
+++ b/test-blink/test.c
@@ -2,6 +2,7 @@
 
 #include <libopencm3/cm3/cortex.h>
 #include <libopencm3/cm3/nvic.h>
+#include <libopencm3/cm3/scb.h>
 #include <libopencm3/cm3/systick.h>
 #include <libopencm3/stm32/rcc.h>
 #include <libopencm3/stm32/gpio.h>
@@ -48,6 +49,8 @@ int main(void)
 	clock_setup();
 	gpio_setup();
 	tick_setup();
+	// This is needed when programming via serial boot loader, harmless otherwise.
+	SCB_VTOR = 0x08000000;
 	cm_enable_interrupts();
 
 	for (;;) {
-- 
2.39.2