nrf5340 net core upgrade

[Jason]

Hi,

I just found that upgrade the net core need to set CONFIG_SERIAL=y and enable the UART in dts file, otherwise, it hangs on the network_core_pcd_cmdset function when upgrading the net core FW,  pcd_fw_copy_status_get() always returns 0.  Is this expected?  if yes, I would like to disable the net core's UART to save the current consumption, any workarounds?

static int network_core_pcd_cmdset(const void *src_addr, size_t len, bool wait)
{
	int err;
	/* Ensure that the network core is turned off */
	nrf_reset_network_force_off(NRF_RESET, true);

	err = pcd_cmd_write(src_addr, len, PCD_NET_CORE_APP_OFFSET);
	if (err != 0) {
		LOG_INF("Error while writing PCD cmd: %d", err);
		return err;
	}

	nrf_reset_network_force_off(NRF_RESET, false);
	LOG_INF("Turned on network core");

	if (!wait) {
		return 0;
	}

	do {
		/* Wait for 1 second to avoid issue where network core
		 * is unable to write to shared RAM.
		 */
		k_busy_wait(1 * USEC_PER_SEC);

		err = pcd_fw_copy_status_get();
	} while (err == PCD_STATUS_COPY);

	if (err == PCD_STATUS_COPY_FAILED) {
		LOG_ERR("Network core update failed");
		return err;
	}

	nrf_reset_network_force_off(NRF_RESET, true);
	LOG_INF("Turned off network core");
	network_core_pcd_tidy();
	return 0;
}

[Sigurd Hellesvik]

Hi,

I will look into this behaviour. But first, I will ask some questions for some context:

Which version of the SDK do you use?

How was the new netcore firmware transferred to the nRF5340?

Do you update the network core from the application or from MCUboot?

Regards,
Sigurd Hellesvik

[Jason]

Hi,

Sigurd Hellesvik said:

Which version of the SDK do you use?

 NCS 2.3.0

Sigurd Hellesvik said:

How was the new netcore firmware transferred to the nRF5340?

 I transfer the FW  via BLE(NCS standard SMP protocol) and USB CDC(Our own custom protocol ), and both of them have the same issue. By the way, when it hangs on the network core upgrade,  if I reset the nrf5340 via reset PIN, it can continue to upgrade the network core successfully.

Sigurd Hellesvik said:

Do you update the network core from the application or from MCUboot?

transfer the FW from the application, and do the image swap from MCUBoot .

in addition, I upgrade the application core and network core over the external flash at the same time (The simultaneous update of multiple images).

[Jason]

Hi,

I added hci_rpmsg.conf in the child_image folder and set CONFIG_SERIAL=n, your sample works.

And then I compared the difference with my project,  there was an extra Cmake attachment  -Dhci_rpmsg_b0n_OVERLAY_CONFIG:STRING="overlay-minimal-size.conf" in my project setting, because my project has ANT+ feature, the flash is not enough if without this argument.

I added the same argument in your sample, and I saw the same behavior, so it relates to the overlay-minimal-size.conf, but I have to build with this configuration.

[Sigurd Hellesvik]

The minimal overlay can be seen here: https://github.com/nrfconnect/sdk-nrf/blob/main/samples/nrf5340/netboot/overlay-minimal-size.conf

For testing, can you modify this temporarily to figure out which of the disabled features cause the issue?

Regards,
Sigurd Hellesvik

[Jason]

firstly  CONFIG_NETBOOT_MIN_PARTITION_SIZE should be enabled, and I tried to enable other features,  e.g. CONFIG_BOOT_BANNER=y, but got a build error that flash is overflow. so I can not figure out which of the disabled features causes the issue

[Sigurd Hellesvik]

CONFIG_NETBOOT_MIN_PARTITION_SIZE is just for the partition size, so I do not think this is what causes the issue.

I suggest that your test without this configuration to find which of the other configurations cause the issue.

Regards,
Sigurd Hellesvik

[Jason]

Hi,

this issue is caused by CONFIG_RESET_ON_FATAL_ERROR=n, and it was fixed after I set it to y in overlay-minimal-size.conf. 

one more question, is it possible to set up CONFIG_RESET_ON_FATAL_ERROR or overlay-minimal-size.conf in my project directory instead of modifying the overlay-minimal-size.conf in NCS directly?

[Sigurd Hellesvik]

Jason said:

this issue is caused by CONFIG_RESET_ON_FATAL_ERROR=n, and it was fixed after I set it to y in overlay-minimal-size.conf. 

Good job tracking this down!

It is a bit awkward, but think you can add "-Dhci_rpmsg_b0n_CONFIG_RESET_ON_FATAL_ERROR=y" after you include the minimal conf.

Alternatively, you can point -Dhci_rpmsg_b0n_OVERLAY_CONFIG:STRING to a local copy of your overlay-minimal-size.conf. For this you must use full path, or CMake for a relative path to project dir. See this sample for how to use Cmake to set Kconfig variables.

However, the issue could be cause by anomaly [161] RESET: Core is not fully reset after Force-OFF.
This should be handeled by our MDK, but there might be a bug there.
A possible solution is to add the following to the beginning of SystemInit() in the net core:

if (((NRF_RESET_NS->RESETREAS & RESET_RESETREAS_SREQ_Msk) || 

        (NRF_RESET_NS->RESETREAS & RESET_RESETREAS_LOCKUP_Msk)) &&

        !(NRF_RESET_NS->RESETREAS & RESET_RESETREAS_LSREQ_Msk)) 

    {

        NVIC_SystemReset();

    }

    

    /* Clear LSREQ bit to allow workaround to be applied on subsequent resets */   NRF_RESET_NS->RESETREAS = RESET_RESETREAS_LSREQ_Msk;

Regards,
Sigurd Hellesvik

[Jason]

Thanks, all of the workaround works. 

by the way, if CONFIG_RESET_ON_FATAL_ERROR=n, what will happen on the network core when a fatal error occurs, crash, or ...?

[Sigurd Hellesvik]

Jason said:

by the way, if CONFIG_RESET_ON_FATAL_ERROR=n, what will happen on the network core when a fatal error occurs, crash, or ...?

The network core will not reset on its own, and must be reset by other means.
For example, from nRF5340 RESET: "When the application core performs a soft reset, the network core is held in reset, see Network Force-OFF. A soft reset in the network core will only cause the network core to reset."

Depending a bit on your application, you might want the network core to reset automatically or not, so that would be up to you.

Regards,
Sigurd Hellesvik