samples/wifi/scan broken without programmed OTP

[JordanYates]

The WiFi scan sample is currently broken is several ways when the OTP isn't programmed:
https://github.com/nrfconnect/sdk-nrf/blob/ea31b211be92f0f837cec1a70be665ec6ff712c3/samples/wifi/scan/src/main.c#L297

* net_if_down() fails with -EAGAIN because it fails to come up in the first place without a MAC address

* NET_REQUEST_ETHERNET_SET_MAC_ADDRESS fails because it is trying to pass the MAC address as a string, instead of a struct ethernet_config

[Simonr]

Hi

Our devices are shipped with the OTP memory access in the disabled state, so some steps are necessary to enable write/read access of the OTP, and to let you I.E. write a MAC address onto the nRF7002. This is described in this application note under OTP memory programming.

The following steps are required:

1. Set the protection registers (REGION.PROTECT[0..3]) to 0x50FA50FA to enable read/write access of the remaining OTP memory locations with the Wi-Fi Radio test command wifi_radio_ficr_prog otp_write_params 0x100 0x50FA50FA.
2. Reboot the device to finish enabling read/write access to the OTP memory.
3. Update the OTP memory registers described in various steps in Production line operations.
4. Set the OTP memory to protected state with the Wi-Fi Radio test command wifi_radio_ficr_prog otp_write_params 0x100 0x00000000.

Best regards,

Simon

[JordanYates]

I am not asking how to configure the OTP, I am notifying you that the sample is incorrect when it is not programmed.

Explicitly because the sample is attempting to handle that case, and failing.

[Simonr]

Ah, okay. Sorry about the misunderstanding. I have reported this internally now, but if you want to set your MAC address manually without writing a MAC address onto the OTP memory, you can add the following to your main file (where the code snippet goes into the beginning of your main loop.

#include <zephyr/net/ethernet_mgmt.h>
#include <zephyr/net/ethernet.h>

		struct net_if *iface = net_if_get_default();
	char mac_addr_change[]={0x12, 0x34, 0x56, 0x78, 0x90, 0x12};
	struct ethernet_req_params params;
	int ret;

	memcpy(params.mac_address.addr, mac_addr_change, 6);
	net_if_down(iface);

	ret = net_mgmt(NET_REQUEST_ETHERNET_SET_MAC_ADDRESS, iface,
			&params, sizeof(struct ethernet_req_params));
	if(ret != 0) {
		LOG_ERR("unable to change mac address");
		return;
	}
	ret = memcmp(net_if_get_link_addr(iface)->addr, mac_addr_change,
			sizeof(mac_addr_change));
	if(ret != 0) {
		LOG_ERR("mac address change failed");
		return;
	}
	LOG_DBG("MAC changed to %x:%x:%x:%x:%x:%x\n", \
	mac_addr_change[0], mac_addr_change[1], mac_addr_change[2], \
	mac_addr_change[3], mac_addr_change[4], mac_addr_change[5]);
	net_if_up(iface);

Best regards,

Simon