In case a RESET command is received in the middle of a OTA DFU, reboot to bootloader to allow the DFU app to recover previously interrupted transfers, instead of reverting to the last working firmware and launching it

lib/sdk11/components/libraries/bootloader_dfu/bootloader.c

@@ -44,7 +44,8 @@ typedef enum
     BOOTLOADER_SETTINGS_SAVING,                         /**< Bootloader status for indicating that saving of bootloader settings is in progress. */
     BOOTLOADER_COMPLETE,                                /**< Bootloader status for indicating that all operations for the update procedure has completed and it is safe to reset the system. */
     BOOTLOADER_TIMEOUT,                                 /**< Bootloader status field for indicating that a timeout has occured and current update process should be aborted. */
-    BOOTLOADER_RESET,                                   /**< Bootloader status field for indicating that a reset has been requested and current update process should be aborted. */
+    BOOTLOADER_SYS_RESET,                               /**< Bootloader status field for indicating that a reset has been requested and current update process should be aborted. */
+    BOOTLOADER_RESET_TO_SELF,                           /**< Bootloader status field for indicating that a reset has been requested and current update process should be aborted and the bootloader must be reentered. */
 } bootloader_status_t;
 
 static pstorage_handle_t        m_bootsettings_handle;  /**< Pstorage handle to use for registration and identifying the bootloader module on subsequent calls to the pstorage module for load and store of bootloader setting in flash. */
@@ -136,7 +137,8 @@ static void wait_for_events(void)
 
     if ((m_update_status == BOOTLOADER_COMPLETE) ||
         (m_update_status == BOOTLOADER_TIMEOUT) ||
-        (m_update_status == BOOTLOADER_RESET) )
+        (m_update_status == BOOTLOADER_SYS_RESET) ||
+        (m_update_status == BOOTLOADER_RESET_TO_SELF))
     {
       // When update has completed or a timeout/reset occured we will return.
       return;
@@ -320,7 +322,9 @@ void bootloader_dfu_update_process(dfu_update_status_t update_status)
   }
   else if (update_status.status_code == DFU_RESET)
   {
-    m_update_status = BOOTLOADER_RESET;
+    m_update_status = update_status.restart_into_bootloader == false
+      ? BOOTLOADER_SYS_RESET 
+      : BOOTLOADER_RESET_TO_SELF;
   }
   else
   {
@@ -328,6 +332,10 @@ void bootloader_dfu_update_process(dfu_update_status_t update_status)
   }
 }
 
+bool bootloader_must_reset_to_self(void)
+{
+  return m_update_status == BOOTLOADER_RESET_TO_SELF;
+}
 
 uint32_t bootloader_init(void)
 {

lib/sdk11/components/libraries/bootloader_dfu/bootloader.h

@@ -32,6 +32,13 @@
  */
 uint32_t bootloader_init(void);
 
+/**@brief Function to check if bootloader must be reentered after a reset
+ * @details: This function can only be called after bootloader_dfu_start returns
+ * @retval     true          If device must reboot to the bootloader
+ * @retval     false         If device must reboot to the application, if possible
+ */
+bool bootloader_must_reset_to_self(void);
+
 /**@brief Function for validating application region in flash.
  * @retval     true          If Application region is valid.
  * @retval     false         If Application region is not valid.

lib/sdk11/components/libraries/bootloader_dfu/dfu_dual_bank.c

@@ -82,6 +82,7 @@ static void pstorage_callback_handler(pstorage_handle_t * p_handle,
     APP_ERROR_CHECK(result);
 }
 
+
 /**@brief Function for handling the DFU timeout.
  *
  * @param[in] p_context The timeout context.
@@ -710,6 +711,14 @@ void dfu_reset(void)
 
     update_status.status_code = DFU_RESET;
 
+    // If we are still receiving packets, and we are expecting more of them,
+    //  and we receive the RESET command, this means the DFU app is trying
+    //  to interrupt and recover a failed previous attempt of FLASHing a new
+    //  application. Make sure to reboot into DFU mode instead of starting 
+    //  a previously stored application (specially valid for double bank 
+    //  bootloaders
+    update_status.restart_into_bootloader = (m_dfu_state == DFU_STATE_RX_DATA_PKT && m_data_received != m_image_size);
+
     bootloader_dfu_update_process(update_status);
 }
 

lib/sdk11/components/libraries/bootloader_dfu/dfu_single_bank.c

@@ -607,6 +607,14 @@ void dfu_reset(void)
 
     update_status.status_code = DFU_RESET;
 
+    // If we are still receiving packets, and we are expecting more of them,
+    //  and we receive the RESET command, this means the DFU app is trying
+    //  to interrupt and recover a failed previous attempt of FLASHing a new
+    //  application. Make sure to reboot into DFU mode instead of starting 
+    //  a previously stored application (specially valid for double bank 
+    //  bootloaders
+    update_status.restart_into_bootloader = (m_dfu_state == DFU_STATE_RX_DATA_PKT && m_data_received != m_image_size);
+
     bootloader_dfu_update_process(update_status);
 }
 

lib/sdk11/components/libraries/bootloader_dfu/dfu_types.h

@@ -24,6 +24,7 @@
 #define DFU_TYPES_H__
 
 #include <stdint.h>
+#include <stdbool.h>
 #include "nrf_sdm.h"
 #include "nrf_mbr.h"
 #include "nrf.h"
@@ -154,6 +155,7 @@ typedef struct
     uint32_t                 bl_size;                                                                   /**< Size of the recieved BootLoader. */
     uint32_t                 app_size;                                                                  /**< Size of the recieved Application. */
     uint32_t                 sd_image_start;                                                            /**< Location in flash where the received SoftDevice image is stored. */
+    bool                     restart_into_bootloader;                                                   /**< If the chip must be reset and must reenter bootloader mode. */
 } dfu_update_status_t;
 
 /**@brief Update complete handler type. */

src/main.c

@@ -134,6 +134,7 @@ uint32_t* dbl_reset_mem = ((uint32_t*) DFU_DBL_RESET_MEM);
 // true if ble, false if serial
 bool _ota_dfu = false;
 bool _ota_connected = false;
+bool _ota_was_active = false;
 bool _sd_inited = false;
 
 bool is_ota(void) {
@@ -192,6 +193,10 @@ int main(void) {
   // Return when DFU process is complete (or not entered at all)
   check_dfu_mode();
 
+  // Check if we must reenter the bootloader after reset, instead of 
+  // launching the user application
+  bool bootloader_must_be_reentered = bootloader_must_reset_to_self();
+
   // Reset peripherals
   board_teardown();
 
@@ -202,7 +207,9 @@ int main(void) {
    * - sd_softdevice_vector_table_base_set(APP_ADDR)
    * - jump to App reset
    */
-  if (bootloader_app_is_valid() && !bootloader_dfu_sd_in_progress()) {
+  if (!bootloader_must_be_reentered && 
+       bootloader_app_is_valid() && 
+      !bootloader_dfu_sd_in_progress()) {
     PRINTF("App is valid\r\n");
     if (is_sd_existed()) {
       // MBR forward IRQ to SD (if not already)
@@ -220,9 +227,14 @@ int main(void) {
     bootloader_app_start();
   }
 
-  // No application was loaded, reset the system with the OTA DFU update
-  NRF_POWER->GPREGRET = DFU_MAGIC_OTA_RESET;
-
+  // No application was loaded or we need to reenter the bootloader
+  
+  // Reset the system with the OTA DFU update in case we were in it, 
+  // to allow completion of FLASHING, otherwise, default to normal reset
+  if (_ota_was_active) {
+    NRF_POWER->GPREGRET = DFU_MAGIC_OTA_RESET;
+  }
+  
   NVIC_SystemReset();
 }
 
@@ -440,6 +452,9 @@ uint32_t proc_ble(void) {
         sd_ble_gap_phy_update(evt->evt.gap_evt.conn_handle, &phys);
 
         _ota_connected = true;
+
+        // Remember someone connected to BLE        
+        _ota_was_active = true;
         led_state(STATE_BLE_CONNECTED);
         break;
       }

src/usb/msc_uf2.c

@@ -171,6 +171,7 @@ void tud_msc_write10_complete_cb(uint8_t lun)
     dfu_update_status_t update_status;
     memset(&update_status, 0, sizeof(dfu_update_status_t ));
     update_status.status_code = DFU_RESET;
+    update_status.restart_into_bootloader = false;
 
     bootloader_dfu_update_process(update_status);
 
@@ -195,9 +196,10 @@ void tud_msc_write10_complete_cb(uint8_t lun)
       {
         // update bootloader always end with reset
         update_status.status_code = DFU_RESET;
+        update_status.restart_into_bootloader = false;
 
         // Location of current stored new bootloader
-        uint32_t * new_bootloader = (uint32_t *) BOOTLOADER_ADDR_NEW_RECIEVED;
+        uint32_t * new_bootloader = (uint32_t *) BOOTLOADER_ADDR_NEW_RECEIVED;
 
         PRINT_HEX(new_bootloader);
 

src/usb/uf2/uf2cfg.h

@@ -32,4 +32,4 @@
 #define BOOTLOADER_ADDR_END           BOOTLOADER_MBR_PARAMS_PAGE_ADDRESS
 
 // Address where new bootloader is written before activation (skip application data)
-#define BOOTLOADER_ADDR_NEW_RECIEVED  (USER_FLASH_END-DFU_BL_IMAGE_MAX_SIZE)
+#define BOOTLOADER_ADDR_NEW_RECEIVED  (USER_FLASH_END-DFU_BL_IMAGE_MAX_SIZE)