DFU target API integration

[Jithin A]

Hi,

I am trying to integrate DFU into my application. Below is what I need to do.

I receive OTA application image over BLE (I can not use legacy DFU feature as we are using our own encryption for all the data exchange over BLE) and I need to write the application image.

I try using dfu_target APIs to do the work and I see undefined reference error for all the dfu_target APIs.

Please let me know what I need to do to include dfu_target APIs into my application.

Thank you in advance.

[Sigurd Hellesvik]

Hi,

See DFU target target library.

Our nRF9160: Full modem firmware update using SMP Server sample uses the dfu_target library, so you can get some inspiration from that as well.

Regards,
Sigurd Hellesvik

[Jithin A]

Hi Sigurd,

Thank you for your response

I am also referring the same library for integration but I do not see any details on how to enable the target library in any application.

Let me share my config so that you can point me if I am missing anything.

I included the below header file:

#include <dfu/dfu_target.h>

I also added below config in my prj.conf file

CONFIG_DFU_TARGET=y

CONFIG_DFU_TARGET_MCUBOOT=y

Still I see below error:

undefined reference to `dfu_target_done'
undefined reference to `dfu_target_offset_get'
undefined reference to `dfu_target_schedule_update'
undefined reference to `dfu_target_write'

 

[Sigurd Hellesvik]

Jithin A said:

functions inside secure

Can you specify what you mean by "inside secure", either of the following?

1. Build for nrf5340dk_nrf5340_cpuapp
2. Build for nrf5340dk_nrf5340_cpuapp_ns, but manually call functions from secure side

Jithin A said:

Also I see there are many output build images and I want to know which output build image is suitable for DFU over BLE. (NOTE: I have 2 images in my application non-secure and TF-M images).

I need to update both the images over DFU. I am confused which build image to write in the secondary slot so the MCUBoot can update both non-secure and secure in the next boot.

In the nRF Connect SDK, the dfu_application.zip is used when updating both cores simultaneously over Bluetooth Low Energy.
For an example see Simultaneous DFU for app and net core of nRF5340.

Regards,
Sigurd Hellesvik

[Jithin A]

Sigurd Hellesvik said:

In the nRF Connect SDK, the dfu_application.zip is used when updating both cores simultaneously over Bluetooth Low Energy.

Actually I need bin file.

The file will be transmitted over BLE from the App and my device will write the bin into secondary slot which is allotted ~400kb. 

No need of updating net core every time.

Please guide me to the respective file.

[Sigurd Hellesvik]

See https://developer.nordicsemi.com/nRF_Connect_SDK/doc/latest/nrf/app_build_system.html

Regards,
Sigurd Hellesvik

[Jithin A]

I mean if I call any dfu_target functions in secure_partition I see above mentioned error.

If I call the same functions in main.c (outside secure partition - non-secure) it is working fine.

But I need to call these functions in secure_partition.

[Sigurd Hellesvik]

Well, you can include it manually using CMake:

+++ b/samples/tfm/tfm_secure_peripheral/secure_peripheral_partition/CMakeLists.txt
@@ -21,6 +21,7 @@ target_sources(tfm_app_rot_partition_spp
     PRIVATE
         secure_peripheral_partition.c
         util.c
+        ${ZEPHYR_BASE}/../nrf/subsys/dfu/dfu_target/src/dfu_target.c
 )
 
 target_include_directories(tfm_app_rot_partition_spp
@@ -29,6 +30,7 @@ target_include_directories(tfm_app_rot_partition_spp
         ${HAL_NORDIC_PATH}/nrfx
         ${HAL_NORDIC_PATH}/nrfx/mdk
         ${HAL_NORDIC_PATH}/nrfx/drivers/include
+        ${ZEPHYR_BASE}/../nrf/include/dfu
 )

However, all the dependencies of this file are not included, so it does not build.

I do not think we have any "DEPENDENCY" for dfu_target in Secure yet.
Therefore I think you have to manually use CMakeLists.txt to include dependencies here.

Another alternative would be to add the .h and .c files from dfu_target to your project, and slim away other dependencies.

Regards,
Sigurd Hellesvik

[Sigurd Hellesvik]

Hi again,

I checked this with our developers.

TF-M is another environment than Zephyr.
Therefore you  can not use Zephyrs libraries from the secure partition.
You can not use dfu_target from the secure partition.

If you need to write files to the bootloader slots from the secure partition, you need to write this functionality yourself.

Regards,
Sigurd Hellesvik

[Jithin A]

Thank you for the response

Sigurd Hellesvik said:

If you need to write files to the bootloader slots from the secure partition, you need to write this functionality yourself.

I do not find any reference for writing files to bootloader slots from the secure partition.

Please point me to any if so. 

It would be good at least if there is any flash write function where we can give the destination address to write into.

Please share any reference if you have to do so.

Thank you once again.

[Sigurd Hellesvik]

You will have to use the nrfx driver for flash (NVMC) directly.

See how the Secure Peripheral partition sample uses the nrfx HAL.

See https://github.com/nrfconnect/sdk-hal_nordic/blob/main/nrfx/drivers/include/nrfx_nvmc.h

Regards,
Sigurd Hellesvik

[Jithin A]

Thank you Sigurd

Yes we can use nrfx driver inside secure partition and I see the functions are pretty much what I was looking for.

I will give it a try.

Thank you for all the response.

Will get back to you if any.