From 07be559e9429a6ada5267510f89e6eaab2b971fe Mon Sep 17 00:00:00 2001
From: BlackMark <me@blackmark.me>
Date: Wed, 1 Apr 2020 19:04:27 +0200
Subject: [PATCH] Add tsb bootloader support

---
 fantemp/bootloader.cpp  | 46 +++++++++++++++++++++++++++++++++++++++++
 fantemp/bootloader.hpp  | 24 +++++++++++++++++++++
 fantemp/fantemp.cppproj |  6 ++++++
 fantemp/main.cpp        |  3 +++
 fantemp/terminal.hpp    | 27 ++++++++++++++++++++----
 5 files changed, 102 insertions(+), 4 deletions(-)
 create mode 100644 fantemp/bootloader.cpp
 create mode 100644 fantemp/bootloader.hpp

diff --git a/fantemp/bootloader.cpp b/fantemp/bootloader.cpp
new file mode 100644
index 0000000..b57b4c3
--- /dev/null
+++ b/fantemp/bootloader.cpp
@@ -0,0 +1,46 @@
+#include "bootloader.hpp"
+
+#include <avr/io.h>
+#include <avr/pgmspace.h>
+#include <avr/wdt.h>
+
+namespace {
+
+typedef void (*jmp_fn)() __attribute__((noreturn));
+
+jmp_fn boot = reinterpret_cast<jmp_fn>(0x0000);
+jmp_fn bootloader = reinterpret_cast<jmp_fn>(0x7E00 / 2);
+
+} // namespace
+
+bool Bootloader::handleReset()
+{
+	wdt_reset();
+	uint8_t mcuStatus = MCUSR;
+	MCUSR &= ~(1 << WDRF);
+	wdt_disable();
+	return (mcuStatus & (1 << WDRF));
+}
+
+void Bootloader::reset()
+{
+	wdt_enable(WDTO_15MS);
+	while (true)
+		;
+}
+
+bool Bootloader::check()
+{
+	if (pgm_read_byte(reinterpret_cast<uint16_t>(bootloader) * 2) == 0xF8)
+		return true;
+
+	return false;
+}
+
+void Bootloader::call()
+{
+	if (check())
+		bootloader();
+	else
+		boot();
+}
diff --git a/fantemp/bootloader.hpp b/fantemp/bootloader.hpp
new file mode 100644
index 0000000..8f7574d
--- /dev/null
+++ b/fantemp/bootloader.hpp
@@ -0,0 +1,24 @@
+#pragma once
+
+class Bootloader {
+  public:
+	template <typename Fn>
+	static inline void init(Fn callback)
+	{
+		if (handleReset()) {
+			callback();
+			call();
+		}
+	}
+
+	static inline void enter()
+	{
+		reset();
+	}
+
+  private:
+	static bool handleReset();
+	static void reset();
+	static bool check();
+	static void call();
+};
diff --git a/fantemp/fantemp.cppproj b/fantemp/fantemp.cppproj
index ae268db..7124ef1 100644
--- a/fantemp/fantemp.cppproj
+++ b/fantemp/fantemp.cppproj
@@ -200,6 +200,12 @@
     <Compile Include="adc\hardware.hpp">
       <SubType>compile</SubType>
     </Compile>
+    <Compile Include="bootloader.cpp">
+      <SubType>compile</SubType>
+    </Compile>
+    <Compile Include="bootloader.hpp">
+      <SubType>compile</SubType>
+    </Compile>
     <Compile Include="clock.hpp">
       <SubType>compile</SubType>
     </Compile>
diff --git a/fantemp/main.cpp b/fantemp/main.cpp
index d37fafa..43749c8 100644
--- a/fantemp/main.cpp
+++ b/fantemp/main.cpp
@@ -5,11 +5,14 @@
 #define UART0_INT_VECTORS
 #include "uart/hardware0.hpp"
 
+#include "bootloader.hpp"
 #include "controller.hpp"
 #include "terminal.hpp"
 
 int main()
 {
+	Bootloader::init([]() {});
+
 	using serial = uart::Uart0<uart::Config<115200>>;
 	Terminal<serial> terminal;
 	terminal.init();
diff --git a/fantemp/terminal.hpp b/fantemp/terminal.hpp
index 19739bc..87f6e24 100644
--- a/fantemp/terminal.hpp
+++ b/fantemp/terminal.hpp
@@ -15,6 +15,7 @@ GF(HELP_CMD, "help");
 GF(SHOW_CMD, "show");
 GF(CURVE_CMD, "curve");
 GF(MONITOR_CMD, "monitor");
+GF(BOOTLOADER_CMD, "bootloader");
 
 constexpr auto BACKSPACE = uint8_t{0x7f};
 constexpr auto CTRL_C = uint8_t{0x03};
@@ -109,6 +110,8 @@ class Terminal {
 				printCurve();
 			} else if (strncmp_P(m_inputBuffer, reinterpret_cast<const char *>(MONITOR_CMD), m_inputSize) == 0) {
 				m_state = State::MONITOR;
+			} else if (strncmp_P(m_inputBuffer, reinterpret_cast<const char *>(BOOTLOADER_CMD), m_inputSize) == 0) {
+				handleBootloader();
 			} else {
 				printUnknown();
 			}
@@ -124,10 +127,11 @@ class Terminal {
 	static void printHelp()
 	{
 		m_serial << F("FanTemp command overview: ") << ENDL;
-		m_serial << HELP_CMD << F(" ....: print this help message") << ENDL;
-		m_serial << SHOW_CMD << F(" ....: shows current temperature and fan speed") << ENDL;
-		m_serial << CURVE_CMD << F(" ...: shows the curve used to map temperature to fan speed") << ENDL;
-		m_serial << MONITOR_CMD << F(" .: loops the show command until Ctrl + C is pressed") << ENDL;
+		m_serial << HELP_CMD << F(" .......: print this help message") << ENDL;
+		m_serial << SHOW_CMD << F(" .......: shows current temperature and fan speed") << ENDL;
+		m_serial << CURVE_CMD << F(" ......: shows the curve used to map temperature to fan speed") << ENDL;
+		m_serial << MONITOR_CMD << F(" ....: loops the show command until Ctrl + C is pressed") << ENDL;
+		m_serial << BOOTLOADER_CMD << F(" .: enters the bootloader after 10 seconds") << ENDL;
 	}
 
 	static void showState()
@@ -156,6 +160,21 @@ class Terminal {
 		}
 	}
 
+	static void handleBootloader()
+	{
+		for (int8_t i = 10; i >= 0; --i) {
+			m_serial << i << ENDL;
+			_delay_ms(1000);
+		}
+
+		m_serial << F("Entering bootloader...") << ENDL;
+		m_serial.flushTx();
+
+		_delay_ms(1000);
+
+		Bootloader::enter();
+	}
+
 	static void printUnknown()
 	{
 		m_serial << F("Unknown command \"");