From 3f06d8b5cfb1aeac287af771448ddaa7e166a901 Mon Sep 17 00:00:00 2001
From: Hubert Denkmair <hubert@denkmair.de>
Date: Fri, 22 Apr 2016 11:47:25 +0200
Subject: [PATCH] USB DFU run-time support

---
 include/dfu.h         | 29 +++++++++++++++++++++++
 include/usbd_gs_can.h |  2 ++
 src/dfu.c             | 54 +++++++++++++++++++++++++++++++++++++++++++
 src/main.c            |  5 ++++
 src/usbd_gs_can.c     |  6 +++++
 5 files changed, 96 insertions(+)
 create mode 100644 include/dfu.h
 create mode 100644 src/dfu.c

diff --git a/include/dfu.h b/include/dfu.h
new file mode 100644
index 0000000..a018266
--- /dev/null
+++ b/include/dfu.h
@@ -0,0 +1,29 @@
+/*
+
+The MIT License (MIT)
+
+Copyright (c) 2016 Hubert Denkmair
+
+Permission is hereby granted, free of charge, to any person obtaining a copy
+of this software and associated documentation files (the "Software"), to deal
+in the Software without restriction, including without limitation the rights
+to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+copies of the Software, and to permit persons to whom the Software is
+furnished to do so, subject to the following conditions:
+
+The above copyright notice and this permission notice shall be included in
+all copies or substantial portions of the Software.
+
+THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+THE SOFTWARE.
+
+*/
+
+#pragma once
+
+void dfu_run_bootloader();
diff --git a/include/usbd_gs_can.h b/include/usbd_gs_can.h
index efdad62..78bd66c 100644
--- a/include/usbd_gs_can.h
+++ b/include/usbd_gs_can.h
@@ -41,3 +41,5 @@ uint8_t USBD_GS_CAN_Transmit(USBD_HandleTypeDef *pdev, uint8_t *buf, uint16_t le
 uint8_t USBD_GS_CAN_PrepareReceive(USBD_HandleTypeDef *pdev);
 bool USBD_GS_CAN_CustomDeviceRequest(USBD_HandleTypeDef *pdev, USBD_SetupReqTypedef *req);
 bool USBD_GS_CAN_CustomInterfaceRequest(USBD_HandleTypeDef *pdev, USBD_SetupReqTypedef *req);
+
+bool USBD_GS_CAN_DfuDetachRequested(USBD_HandleTypeDef *pdev);
diff --git a/src/dfu.c b/src/dfu.c
new file mode 100644
index 0000000..5e18f91
--- /dev/null
+++ b/src/dfu.c
@@ -0,0 +1,54 @@
+/*
+
+The MIT License (MIT)
+
+Copyright (c) 2016 Hubert Denkmair
+
+Permission is hereby granted, free of charge, to any person obtaining a copy
+of this software and associated documentation files (the "Software"), to deal
+in the Software without restriction, including without limitation the rights
+to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+copies of the Software, and to permit persons to whom the Software is
+furnished to do so, subject to the following conditions:
+
+The above copyright notice and this permission notice shall be included in
+all copies or substantial portions of the Software.
+
+THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+THE SOFTWARE.
+
+*/
+
+#include "dfu.h"
+#include <stdint.h>
+#include "stm32f0xx_hal.h"
+
+#define SYSMEM_RESET_VECTOR            0x1fffC804
+#define RESET_TO_BOOTLOADER_MAGIC_CODE 0xDEADBEEF
+#define BOOTLOADER_STACK_POINTER       0x20002250
+
+uint32_t dfu_reset_to_bootloader_magic;
+
+void __initialize_hardware_early(void)
+{
+	if (dfu_reset_to_bootloader_magic == RESET_TO_BOOTLOADER_MAGIC_CODE) {
+		void (*bootloader)(void) = (void (*)(void)) (*((uint32_t *) SYSMEM_RESET_VECTOR)); // system memory reset vector
+		dfu_reset_to_bootloader_magic = 0;
+		__set_MSP(BOOTLOADER_STACK_POINTER);
+		bootloader();
+		while (42);
+	} else {
+		SystemInit();
+	}
+}
+
+void dfu_run_bootloader()
+{
+	dfu_reset_to_bootloader_magic = RESET_TO_BOOTLOADER_MAGIC_CODE;
+	NVIC_SystemReset();
+}
diff --git a/src/main.c b/src/main.c
index 7087a53..63e067a 100644
--- a/src/main.c
+++ b/src/main.c
@@ -37,6 +37,7 @@ THE SOFTWARE.
 #include "gs_usb.h"
 #include "can.h"
 #include "led.h"
+#include "dfu.h"
 
 void HAL_MspInit(void);
 void SystemClock_Config(void);
@@ -144,6 +145,10 @@ int main(void)
 
 		led_update(&hLED);
 
+		if (USBD_GS_CAN_DfuDetachRequested(&hUSB)) {
+			dfu_run_bootloader();
+		}
+
 	}
 
 }
diff --git a/src/usbd_gs_can.c b/src/usbd_gs_can.c
index c2ec2ce..eb234ef 100644
--- a/src/usbd_gs_can.c
+++ b/src/usbd_gs_can.c
@@ -595,3 +595,9 @@ uint8_t *USBD_GS_CAN_GetStrDesc(USBD_HandleTypeDef *pdev, uint8_t index, uint16_
 			return 0;
 	}
 }
+
+bool USBD_GS_CAN_DfuDetachRequested(USBD_HandleTypeDef *pdev)
+{
+	USBD_GS_CAN_HandleTypeDef *hcan = (USBD_GS_CAN_HandleTypeDef*)pdev->pClassData;
+	return hcan->dfu_detach_requested;
+}