How can I read the UICR register of 9160?

[xinjiang]

The current project needs to save the ID in the programmable register and use the ID in the application image.

So I save the ID number in the URCI->OTP[0] register. When I read the ID in URCI->OTP[0] in the main function of the application image, a fatal error occurred.

uint32_t get_id_from_uicr(){
        uint32_t id;
        id = (NRF_UICR_S->OTP[0]);
        return id;
}

As far as I know, UICR can only be read in secure code.

So I execute this code in the main function of spm and get the ID normally. How can I pass the ID to the application image(not via flash)?

Or is there any other better way to store this ID?

spm.c:

uint32_t get_id_from_uicr(){
        uint32_t id;
        id = (NRF_UICR_S->OTP[0]);
        return id;
}

void main(void)
{
    uint32_t id;
    id = get_imei_from_uicr();
	spm_config();
	spm_jump();
}

[Sigurd]

Hi,

How can I pass the ID to the application image(not via flash)?

If you want to read the UICR (or FICR) from the application, you need to use secure services.

See this sample:

https://github.com/nrfconnect/sdk-nrf/blob/master/samples/nrf9160/secure_services/src/main.c

https://developer.nordicsemi.com/nRF_Connect_SDK/doc/1.7.0/nrf/samples/nrf9160/secure_services/README.html

[xinjiang]

I imitated the method of reading the FICR register in secure services to read the UICR register. The spm_request_read() function returns error code -1. How can I solve this problem?

static int read_uicr_word(uint32_t *result, const volatile uint32_t *addr)
{
	printk("Read UICR (address 0x%08x):\n", (uint32_t)addr);
	int ret = spm_request_read(result, (uint32_t)addr, sizeof(uint32_t));

	if (ret != 0) {
		printk("Could not read UICR (err: %d)\n", ret);
	}
	return ret;
}
void main(void)
{
    uint32_t uicr_info;
    if(read_uicr_word(&ficr_info, &NRF_UICR_S->OTP[0]) == 0) {
	    printk("UICR = 0x%08X\n\n", uicr_info);        
    }
    
	printk("Reboot in %d seconds.\n", sleep_time_s);
	k_sleep(K_SECONDS(5));

	sys_reboot(0); /* Argument is ignored. */    
}

Log:

Read UICR (address 0x00ff8108):
Could not read UICR (err: -1)
Reboot in 5 seconds.

[Sigurd]

xinjiang said:

How can I solve this problem?

I see now that UICR is not in the allowed read range:

https://github.com/nrfconnect/sdk-nrf/blob/v1.7.0/subsys/spm/secure_services.c#L73

So you need to append some this like this to the ranges array, so it looks something like this:

	static const struct read_range ranges[] = {
#ifdef PM_MCUBOOT_ADDRESS
		/* Allow reads of mcuboot metadata */
		{.start = PM_MCUBOOT_PAD_ADDRESS,
		 .size = PM_MCUBOOT_PAD_SIZE},
#endif
		{.start = FICR_PUBLIC_ADDR,
		 .size = FICR_PUBLIC_SIZE},
		{.start = FICR_RESTRICTED_ADDR,
		 .size = FICR_RESTRICTED_SIZE},
		{.start = NRF_UICR_S_BASE+0x108, //OTP[0] address
		 .size = 0x4},
	};

[xinjiang]

I did not find secure_services.c under the secure_services demo. According to the macro configuration, the file should be imported, but the actual situation is the opposite.

secure_services demo:

nrf/subsys/spm/Kconfig:

nrf/subsys/spm/CMakeLists.txt:

When I tried to add CONFIG_SPM to spm, a fatal error occurred: CONFIG_SPM and CONFIG_IS_SPM conflict. Do I modify secure_services.c in spm image or modify it in app image?

[Sigurd]

Just modify the file in found in subsys/spm/secure_services.c

[xinjiang]

Thank you very much for your method, I can already read the UICR register, but getting the value of UICR->OTP[0] is wrong. I write 0x12345678 to UICR->OTP[0], but it reads 0xDEADDEAD. The specification says that the register is readable. What is the problem?

[Sigurd]

xinjiang said:

0xDEADDEAD

This indicates that you don't have permission to read it.

See these links:

https://infocenter.nordicsemi.com/topic/ps_nrf9160/uicr.html#register.KEYSLOT.CONFIG.PERM

infocenter.nordicsemi.com/.../kmu.html