Delay autoreset to bootloader

This waits for 250ms, just like the Arduino SAM and SAMD cores do (AVR
waits only 120ms), to allow the USB host and application a bit more time
to close the port and clean up.

Author: matthijskooijman

cores/arduino/stm32/bootloader.h

@@ -14,6 +14,10 @@
 extern "C" {
 #endif /* __cplusplus */
 
+void scheduleBootloaderReset();
+void cancelBootloaderReset();
+void bootloaderSystickHandler();
+
 /* Request to jump to system memory boot */
 void jumpToBootloaderRequested(void);
 

cores/arduino/stm32/usb/cdc/usbd_cdc_if.c

@@ -33,6 +33,9 @@
   #define CDC_MAX_PACKET_SIZE USB_MAX_EP0_SIZE
 #endif
 
+// TODO: Put this elsewhere
+#define BOOTLOADER_RESET_1200_BAUD
+
 /*
  * The value USB_CDC_TRANSMIT_TIMEOUT is defined in terms of HAL_GetTick() units.
  * Typically it is 1ms value. The timeout determines when we would consider the
@@ -169,9 +172,6 @@ static int8_t USBD_CDC_Control(uint8_t cmd, uint8_t *pbuf, uint16_t length)
       linecoding.format     = pbuf[4];
       linecoding.paritytype = pbuf[5];
       linecoding.datatype   = pbuf[6];
-      if (linecoding.bitrate == 1200) {
-        jumpToBootloaderRequested();
-      }
       break;
 
     case CDC_GET_LINE_CODING:
@@ -203,6 +203,19 @@ static int8_t USBD_CDC_Control(uint8_t cmd, uint8_t *pbuf, uint16_t length)
       break;
   }
 
+#ifdef BOOTLOADER_RESET_1200_BAUD
+  if (cmd == CDC_SET_LINE_CODING || cmd == CDC_SET_CONTROL_LINE_STATE) {
+    // Auto-reset into the bootloader is triggered when the port, already
+    // open at 1200 bps, is closed. Cancel the reset when the port is
+    // opened again.
+    if (linecoding.bitrate == 1200 && !lineState) {
+      scheduleBootloaderReset();
+    } else {
+      cancelBootloaderReset();
+    }
+  }
+#endif /* BOOTLOADER_RESET_1200_BAUD */
+
   return ((int8_t)USBD_OK);
 }
 

libraries/SrcWrapper/src/stm32/bootloader.c

@@ -11,7 +11,10 @@
  * STM32 built-in bootloader in system memory support
  */
 
+static const uint32_t BOOTLOADER_DELAY_MS = 250;
 static bool BootIntoBootloaderAfterReset;
+static uint32_t countdown = 0;
+
 
 /* Request to jump to system memory boot */
 WEAK void jumpToBootloaderRequested(void)
@@ -116,6 +119,32 @@ WEAK void jumpToBootloaderIfRequested(void)
   }
 }
 
+/**
+  * Scheduler a reset into the bootloader after a delay.
+  */
+void scheduleBootloaderReset()
+{
+  countdown = BOOTLOADER_DELAY_MS;
+}
+
+/**
+  * Cancel a previously scheduled bootloader reset.
+  */
+void cancelBootloaderReset()
+{
+  countdown = 0;
+}
+
+/**
+  * Bootloader systick handler, should be called every ms
+  */
+void bootloaderSystickHandler()
+{
+  if (countdown && --countdown == 0) {
+    jumpToBootloaderRequested();
+  }
+}
+
 /*
  * Legacy maple bootloader support
  */

libraries/SrcWrapper/src/stm32/clock.c

@@ -37,6 +37,7 @@
   */
 #include "backup.h"
 #include "clock.h"
+#include "bootloader.h"
 #include "stm32yyxx_ll_cortex.h"
 
 #ifdef __cplusplus
@@ -88,6 +89,7 @@ void SysTick_Handler(void)
   HAL_IncTick();
   HAL_SYSTICK_IRQHandler();
   osSystickHandler();
+  bootloaderSystickHandler();
 }
 
 /**