Jump to system memory boot from user application

Fixes stm32duino#706 Signed-off-by: Frederic Pillon <[email protected]>
fpistm · Oct 17, 2019 · 1f9772e · 1f9772e
1 parent e1f9868
commit 1f9772e
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Showing 6 changed files with 79 additions and 3 deletions.
diff --git a/cores/arduino/main.cpp b/cores/arduino/main.cpp
@@ -20,7 +20,6 @@
 #define ARDUINO_MAIN
 #include "Arduino.h"
 
-
 // Weak empty variant initialization function.
 // May be redefined by variant files.
 void initVariant() __attribute__((weak));
@@ -30,7 +29,6 @@ void initVariant() { }
 // Otherwise, statically allocated objects that need HAL may fail.
 __attribute__((constructor(101))) void premain()
 {
-
  // Required by FreeRTOS, see http:https://www.freertos.org/RTOS-Cortex-M3-M4.html
 #ifdef NVIC_PRIORITYGROUP_4
  HAL_NVIC_SetPriorityGrouping(NVIC_PRIORITYGROUP_4);

diff --git a/cores/arduino/stm32/backup.h b/cores/arduino/stm32/backup.h
@@ -58,6 +58,13 @@ extern "C" {
 #endif /* HID_MAGIC_NUMBER_BKP_VALUE */
 #endif /* BL_HID */
 
+#if !defined(SYSBL_MAGIC_NUMBER_BKP_INDEX)
+#define SYSBL_MAGIC_NUMBER_BKP_INDEX LL_RTC_BKP_DR2
+#endif /* SYSBL_MAGIC_NUMBER_BKP_INDEX */
+#ifndef SYSBL_MAGIC_NUMBER_BKP_VALUE
+#define SYSBL_MAGIC_NUMBER_BKP_VALUE 0x515B
+#endif /* SYSBL_MAGIC_NUMBER_BKP_VALUE */
+
 /* Exported functions ------------------------------------------------------- */
 static inline void resetBackupDomain(void)
 {

diff --git a/cores/arduino/stm32/bootloader.c b/cores/arduino/stm32/bootloader.c
@@ -2,6 +2,7 @@
 
 #include "stm32_def.h"
 #include "backup.h"
+#include "usbd_if.h"
 
 #ifdef BL_LEGACY_LEAF
 void dtr_togglingHook(uint8_t *buf, uint32_t *len)
@@ -37,3 +38,60 @@ void dtr_togglingHook(uint8_t *buf, uint32_t *len)
  }
 }
 #endif /* BL_HID */
+
+/* Request to jump to system memory boot */
+void jumpToBootloaderRequested(void)
+{
+ enableBackupDomain();
+ setBackupRegister(SYSBL_MAGIC_NUMBER_BKP_INDEX, SYSBL_MAGIC_NUMBER_BKP_VALUE);
+ NVIC_SystemReset();
+}
+
+/* Jump to system memory boot from user application */
+void jumpToBootloader(void)
+{
+ enableBackupDomain();
+ if (getBackupRegister(SYSBL_MAGIC_NUMBER_BKP_INDEX) == SYSBL_MAGIC_NUMBER_BKP_VALUE) {
+ setBackupRegister(SYSBL_MAGIC_NUMBER_BKP_INDEX, 0);
+
+#ifdef USBCON
+ USBD_reenumerate();
+#endif
+ void (*sysMemBootJump)(void);
+
+ /**
+ * Get system memory address
+ *
+ * Available in AN2606 document:
+ * Table 116. Bootloader device-dependent parameters
+ */
+ volatile uint32_t sysMem_addr = 0x1FFF0000;
+
+ /* Remap system Flash memory at address 0x00000000 */
+ __HAL_SYSCFG_REMAPMEMORY_SYSTEMFLASH();
+
+ /**
+ * Set jump memory location for system memory
+ * Use address with 4 bytes offset which specifies jump location
+ * where program starts
+ */
+ sysMemBootJump = (void (*)(void))(*((uint32_t *)(sysMem_addr + 4)));
+
+ /**
+ * Set main stack pointer.
+ * This step must be done last otherwise local variables in this function
+ * don't have proper value since stack pointer is located on different position
+ *
+ * Set direct address location which specifies stack pointer in SRAM location
+ */
+ __set_MSP(*(uint32_t *)sysMem_addr);
+
+ /**
+ * Jump to set location
+ * This will start system memory execution
+ */
+ sysMemBootJump();
+
+ while (1);
+ }
+}
diff --git a/cores/arduino/stm32/bootloader.h b/cores/arduino/stm32/bootloader.h
@@ -20,6 +20,12 @@ extern "C" {
 void dtr_togglingHook(uint8_t *buf, uint32_t *len);
 #endif
 
+/* Request to jump to system memory boot */
+void jumpToBootloaderRequested(void);
+
+/* Jump to system memory boot from user application */
+void jumpToBootloader(void);
+
 #ifdef __cplusplus
 }
 #endif /* __cplusplus */

diff --git a/cores/arduino/stm32/hw_config.c b/cores/arduino/stm32/hw_config.c
@@ -37,8 +37,9 @@
  */
 #include "stm32_def.h"
 #include "hw_config.h"
-#include "usbd_if.h"
 #include "dwt.h"
+#include "bootloader.h"
+#include "usbd_if.h"
 
 #ifdef __cplusplus
 extern "C" {
@@ -59,6 +60,9 @@ void hw_config_init(void)
  /* Initialize the HAL */
  HAL_Init();
 
+ /* Check if a jump to system memory boot requested */
+ jumpToBootloader();
+
  /* Configure the system clock */
  SystemClock_Config();
 

diff --git a/cores/arduino/stm32/usb/cdc/usbd_cdc_if.c b/cores/arduino/stm32/usb/cdc/usbd_cdc_if.c
@@ -168,6 +168,9 @@ 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: