Using the DFU Target Library

[fgeldenh]

We use a custom board implementation based on nrf52840 that makes use of a proprietary host transport protocol.

I am trying to implement  FOTA using our transport. We can successfully download the app_update.bin file that is created when using NCS to create the boot images.

I would like to confirm that by using the DFU Target Library I can update the image slot and reboot to the new image.

Is there anything special I need in order to do this?

Second question:

The app_update.bin image is downloaded to external flash. Could you possibly provide me with suggestions as to the external flash configuration should I wish to specify the secondary slot for DFU. We are using QSPI with an MX25R6435FM2IL0 flash chip. The image is downloaded to an offset of 0x300000.

Thank you

[Hung Bui]

Hi Francois, 
I would suggest to take a look at some of our example, for example \nrf\subsys\net\lib\fota_download, \nrf\subsys\zigbee\lib\zigbee_fota\src to see how dfu_target is used. 

But yes, this is correct:

I would like to confirm that by using the DFU Target Library I can update the image slot and reboot to the new image.

I did make an example on how to configure the board to receive image on external flash. Could you take a look at : https://devzone.nordicsemi.com/f/nordic-q-a/84025/changes-in-bootloader--saving-image-in-external-flash-and-transferring-in-internal-via-bootloader/352191#352191

[fgeldenh]

Thank you. I will investigate and verify.

[fgeldenh]

Hi - I have started this implementation. I have included the DFU TARGET in prj.conf. It seems that there is more require as CONFIG_DFU_TARGET_MCUBOOT does ot get set to 1, so the whole thing fails.

Can you tell me apart from CONFIG_DFU_TARGET=y, what else must be set for me to be able to use DFU Traget with my custom DFU implementation.

See attached prj.conf and my code for DFU.At the time I start the process, the latest image has already been downloaded into the external flash.

572725.prj.conf

Fullscreen mydfu.c Download

/********************************************************************
FileName:     	mydfu.c
Dependencies: 	See INCLUDES section
********************************************************************
File Description:

performs dfu update

Change History:
Rev   Date         Description
1.0   Aug 2023    Initial release

********************************************************************/
#include <zephyr/kernel.h>
#include <zephyr/drivers/flash.h>
#include <zephyr/device.h>
#include <zephyr/devicetree.h>
#include <stdio.h>
#include <string.h>
#include "besecure.h"
#include "storage.h"
#include "mydfu.h"
#include "statled.h"
#include "events.h"
#include "watchdog.h"
#include "dfu/dfu_target.h"
#include <zephyr/logging/log.h>
#include <dfu/dfu_target_mcuboot.h>

#define LOG_MODULE_NAME MyDFU
LOG_MODULE_REGISTER(LOG_MODULE_NAME);

#define CONFIG_DFU_TARGET_MCUBOOT

typedef enum
{
  d_init,
  d_loop,
  d_err,
  d_done
} dfuState;

/** V A R I A B L E S */

static enum dfu_target_image_type img_type;
dfuState dstate;
const struct device *flash_dv = DEVICE_DT_GET(DT_ALIAS(spi_flash0));
int rcod;
uint32_t dfuaddr;
uint32_t fragsiz;
int32_t dfutot;
char dfubuff[2048];

extern uint32_t FWTotal;         // total size of fw

static void dfu_target_callback_handler(enum dfu_target_evt_id evt)
{
	switch (evt) {
	case DFU_TARGET_EVT_TIMEOUT:
		break;
	case DFU_TARGET_EVT_ERASE_DONE:
		break;
	}
}

//
//	Main entry point for the user interface state machine
//
void dfuMac(void)
{
 	int err;
   
  switch (dstate)
  {
    case d_init:                  // we get here at startup
    {
      if (sysStat.rdSOFT == 1)
      {
        dfuaddr = 0x300000;
        // read in first block
        rcod = flash_read(flash_dv, dfuaddr, (char*)&dfubuff, (size_t)2048);
        dfuaddr = dfuaddr + 2048;
        if (rcod != 0)
        {
          dstate = d_err;
        }
        else
        {
          // get image type
          fragsiz = 2048;
          img_type = dfu_target_img_type((char*)&dfubuff,	fragsiz);
          // init
          err = dfu_target_init(img_type, 0, FWTotal, dfu_target_callback_handler);
          if (err == -EFBIG) {
            LOG_ERR("%s", "Image too big");
            dstate = d_err;
          } else if (err < 0) {
            LOG_ERR("dfu_target_init error %d", err);
            dstate = d_err;
          }
          dfutot = FWTotal;       // size we have to process
          fragsiz = 2048;         // first fragment is always 2K
          dstate = d_loop;
        }        
      }
      break;
    }

    case d_loop:        // process fragment
    {
      err = dfu_target_write(&dfubuff, fragsiz);
      if (err && err == -EINVAL) {
        LOG_INF("%s", "Image refused");
        dstate = d_err;
      } else if (err != 0) {
        LOG_ERR("dfu_target_write error %d", err);
        dstate = d_err;
      }
      // update our total
      dfutot = dfutot - fragsiz;

      // see if we are done
      if (dfutot == 0)
      {
        dstate = d_done;
      }
      else
      {
        if (dfutot <= 2048)
        {
          fragsiz = dfutot;
        }

        // read in next block
        rcod = flash_read(flash_dv, dfuaddr, (char*)&dfubuff, fragsiz);
        if (rcod != 0)
        {
          dstate = d_err;
        }
      }
      break;
    }

    case d_err:
    {
      err = dfu_target_reset();
      if (err != 0) {
        LOG_ERR("Unable to reset DFU target, err: %d", err);
      }      
      sysStat.rdSOFT = 0;
      break;
    }

   case d_done:
   {
		err = dfu_target_done(true);
		if (err == 0) {
			err = dfu_target_schedule_update(0);
      sysStat.rdSOFT = 0;
		}
    break;
   }

   
  }  // end switch
} // end dfumac

[Hung Bui]

Hi Francois, 
Which issue do you have when you set CONFIG_DFU_TARGET_MCUBOOT=y ?

I don't see that in your prj.conf. 

Normally I would double check in the \build\zephyr\include\generated\autoconfig.h to see if the configuration is set to 1 or 0. VSCode may give wrong interpretation. 

Could you try taking a look at the \modules\lib\memfault-firmware-sdk\examples\nrf-connect-sdk\nrf9160\memfault_demo_app sample ? 
The sample uses fota_download library (which in turn uses dfu_target) to receive image.