From ba865a4ae0a2cc02ba4bcc6bc685ae3c74fd3b19 Mon Sep 17 00:00:00 2001
From: Konrad Kosmatka <kkonrad92@gmail.com>
Date: Sun, 28 Jul 2024 01:42:19 +0200
Subject: [PATCH] Add runtime bootloader switch for STM32

---
 src/Platform/Stm32/Bootloader.cpp   | 78 +++++++++++++++++++++++++++++
 src/Platform/Stm32/Bootloader.hpp   | 27 ++++++++++
 src/Platform/Stm32/UsbCdcStream.cpp | 46 +++++++++++++++--
 3 files changed, 148 insertions(+), 3 deletions(-)
 create mode 100644 src/Platform/Stm32/Bootloader.cpp
 create mode 100644 src/Platform/Stm32/Bootloader.hpp

diff --git a/src/Platform/Stm32/Bootloader.cpp b/src/Platform/Stm32/Bootloader.cpp
new file mode 100644
index 0000000..e742460
--- /dev/null
+++ b/src/Platform/Stm32/Bootloader.cpp
@@ -0,0 +1,78 @@
+/*  SPDX-License-Identifier: GPL-3.0-or-later
+ *
+ *  FM-DX Tuner
+ *  Copyright (C) 2024  Konrad Kosmatka
+ *
+ *  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.
+ */
+
+#ifdef ARDUINO_ARCH_STM32
+#include <tusb.h>
+#include <stm32f0xx_hal.h>
+
+void
+Platform_Stm32_Bootloader(void)
+{
+    tud_disconnect();
+
+    HAL_NVIC_DisableIRQ(PendSV_IRQn);
+    HAL_NVIC_DisableIRQ(USB_IRQn);
+    __HAL_RCC_USB_CLK_DISABLE();
+
+    HAL_NVIC_DisableIRQ(DMA1_Channel1_IRQn);
+    HAL_NVIC_DisableIRQ(DMA1_Channel2_3_IRQn);
+    HAL_NVIC_DisableIRQ(DMA1_Channel4_5_6_7_IRQn);
+    __HAL_RCC_DMA1_CLK_DISABLE();
+
+    HAL_NVIC_DisableIRQ(SPI1_IRQn);
+    __HAL_RCC_SPI1_CLK_DISABLE();
+
+    HAL_NVIC_DisableIRQ(I2C1_IRQn);
+    __HAL_RCC_I2C1_CLK_DISABLE();
+
+    HAL_NVIC_DisableIRQ(USART1_IRQn);
+    HAL_NVIC_DisableIRQ(USART2_IRQn);
+    __HAL_RCC_USART1_CLK_DISABLE();
+    __HAL_RCC_USART2_CLK_DISABLE();
+
+    HAL_NVIC_DisableIRQ(EXTI0_1_IRQn);
+    HAL_NVIC_DisableIRQ(EXTI2_3_IRQn);
+    HAL_NVIC_DisableIRQ(EXTI4_15_IRQn);
+    __HAL_RCC_GPIOA_CLK_DISABLE();
+    __HAL_RCC_GPIOB_CLK_DISABLE();
+    __HAL_RCC_GPIOC_CLK_DISABLE();
+    __HAL_RCC_GPIOD_CLK_DISABLE();
+    __HAL_RCC_GPIOE_CLK_DISABLE();
+    __HAL_RCC_GPIOF_CLK_DISABLE();
+
+    HAL_GPIO_DeInit(GPIOA, 0xFF);
+    HAL_GPIO_DeInit(GPIOB, 0xFF);
+    HAL_GPIO_DeInit(GPIOC, 0xFF);
+    HAL_GPIO_DeInit(GPIOD, 0xFF);
+
+    HAL_RCC_DeInit();
+
+    SysTick->CTRL = 0;
+    SysTick->LOAD = 0;
+    SysTick->VAL = 0;
+
+    __HAL_SYSCFG_REMAPMEMORY_SYSTEMFLASH();
+
+    const uint32_t addr = 0x1FFFC800;
+    __set_MSP(*(uint32_t *)addr);
+
+    /* Jump to System Memory */
+    void (*bootloader)(void) = (void (*)(void)) (*((uint32_t *)(addr + 4)));
+    bootloader();
+    while(1);
+}
+
+#endif /* ARDUINO_ARCH_STM32 */
diff --git a/src/Platform/Stm32/Bootloader.hpp b/src/Platform/Stm32/Bootloader.hpp
new file mode 100644
index 0000000..e4b467b
--- /dev/null
+++ b/src/Platform/Stm32/Bootloader.hpp
@@ -0,0 +1,27 @@
+/*  SPDX-License-Identifier: GPL-3.0-or-later
+ *
+ *  FM-DX Tuner
+ *  Copyright (C) 2024  Konrad Kosmatka
+ *
+ *  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.
+ */
+
+#ifndef FMDX_TUNER_PLATFORM_STM32_BOOTLOADER_H
+#define FMDX_TUNER_PLATFORM_STM32_BOOTLOADER_H
+#ifdef ARDUINO_ARCH_STM32
+
+#include <stddef.h>
+
+void Platform_Stm32_Bootloader(void);
+
+#endif /* ARDUINO_ARCH_STM32 */
+
+#endif /* FMDX_TUNER_PLATFORM_STM32_BOOTLOADER_H */
diff --git a/src/Platform/Stm32/UsbCdcStream.cpp b/src/Platform/Stm32/UsbCdcStream.cpp
index 1f12066..51790fa 100644
--- a/src/Platform/Stm32/UsbCdcStream.cpp
+++ b/src/Platform/Stm32/UsbCdcStream.cpp
@@ -16,8 +16,9 @@
 
 #ifdef ARDUINO_ARCH_STM32
 #include <Arduino.h>
+#include <tusb.h>
 #include "UsbCdcStream.hpp"
-#include "tusb.h"
+#include "Bootloader.hpp"
 
 #define BUFF_SIZE 64
 uint8_t rxBuff[BUFF_SIZE];
@@ -101,8 +102,8 @@ UsbCdcStream::readTx(void)
     return value;
 }
 
-extern "C"
-void tud_cdc_rx_cb(uint8_t itf)
+extern "C" void
+tud_cdc_rx_cb(uint8_t itf)
 {
     uint8_t value;
     while (tud_cdc_n_available(itf))
@@ -116,6 +117,45 @@ void tud_cdc_rx_cb(uint8_t itf)
     }
 }
 
+extern "C" void
+tud_cdc_line_state_cb(uint8_t itf,
+                      bool    dtr,
+                      bool    rts)
+{
+    constexpr unsigned long timeout = 500;
+    constexpr uint8_t count = 5;
+
+    static unsigned long timer = 0;
+    static uint8_t state = 0;
+
+    if (state == 0)
+    {
+        if (dtr == 1 &&
+            rts == 0)
+        {
+            state = 1;
+            timer = millis();
+        }
+        return;
+    }
+
+    if ((millis() - timer) > timeout)
+    {
+        state = 0;
+        return;
+    }
+
+    if ((dtr == 1 && rts == 0 && state % 2 == 0) ||
+        (dtr == 0 && rts == 1 && state % 2 == 1))
+    {
+        state++;
+    }
+
+    if (state == count)
+    {
+        Platform_Stm32_Bootloader();
+    }
+}
 
 UsbCdcStream UsbCdcSerial;