RE: DIY bootloader for nRF5340

Frog — Wed, 09 Oct 2024 20:49:58 GMT

I believe I've resolved this - it seems that there are two vector tables, one in the secure area of the application and one in the non-secure area. The solution is to jump to the reset vector in the secure partition. I copied a few lines from bl_boot.c, resulting in this

__STATIC_INLINE void app_start(uint32_t vector_table_addr)
{
    struct arm_vector_table *vt = (void *)vector_table_addr;
	printk("Inspect vector table at %08x\n", vector_table_addr);
	printk("Stack pointer %08x\n", vt->msp);
	printk("Reset vector %08x\n", (uint32_t)vt->reset);

	// Shut down hardware as needed
	//nrfx_qspi_uninit();
	nrf_clock_int_disable(NRF_CLOCK, 0xFFFFFFFF);

    irq_lock();

	/* Allow any pending interrupts to be recognized */
	__ISB();
	__disable_irq();

	NVIC_Type *nvic = NVIC;

	/* Disable NVIC interrupts */
	for (uint8_t i = 0; i < ARRAY_SIZE(nvic->ICER); i++) 
	{
		nvic->ICER[i] = 0xFFFFFFFF;
	}

	/* Clear pending NVIC interrupts */
	for (uint8_t i = 0; i < ARRAY_SIZE(nvic->ICPR); i++) 
	{
		nvic->ICPR[i] = 0xFFFFFFFF;
	}

	SysTick->CTRL = 0;

	/* Disable fault handlers used by the bootloader */
	SCB->ICSR |= SCB_ICSR_PENDSTCLR_Msk;

	/* Activate the MSP if the core is currently running with the PSP */
	if (CONTROL_SPSEL_Msk & __get_CONTROL()) 
	{
		__set_CONTROL(__get_CONTROL() & ~CONTROL_SPSEL_Msk);
	}

	__DSB(); /* Force Memory Write before continuing */
	__ISB(); /* Flush and refill pipeline with updated permissions */

	__set_PSPLIM(0);
	__set_MSPLIM(0);

	__set_MSP(vt->msp);
	__set_PSP(0);

	vt->reset();
}

Although at the time of writing I'm still having an issue that appears to be to do with timers, k_sleep seems to return almost immediately and I think that's causing spurious timeouts elsewhere in the application code. I'll investigate further and may raise that as a new ticket if appropriate.

RE: DIY bootloader for nRF5340

Einar Thorsrud — Mon, 07 Oct 2024 12:15:05 GMT

Hi,

I am not able to pinpoint the issue in your implementation. However, I wonder if you could just use the implementation from the nRF Immutable bootlaoder, particularily the bl_boot() implementation from bl_boot.c?