Modify the MCUboot's booting process

RE: Modify the MCUboot's booting process

user15146 — Wed, 15 Jun 2022 11:21:01 GMT

[quote user="Erasmo"] Is there a way to stop the device from continuing when there is an error (the button is released) in the board_init() function?[/quote]

You could e.g. call k_panic() when you detect an error. https://docs.zephyrproject.org/3.0.0/reference/kernel/other/fatal.html#kernel-panic

[quote user="Erasmo"]Or is there a way in which I can create a new main.c file that can be used by the MCUboot without modifying the one in the NCS?[/quote]

I don't think so. If you are sure can't do this in your application when it boots, and don't want to change the MCUBoot main.c in NCS, you could always create a PR to the MCUBoot with your changes. https://github.com/zephyrproject-rtos/mcuboot

RE: Modify the MCUboot's booting process

user114965 — Fri, 10 Jun 2022 00:41:40 GMT

Hi,

I created the board.c file in the board folder and was able to set the PIN on High before the bootloader started, although I needed to define the PIN on the bootloader's overlay file to use it in the board.c file.
I have a condition that verifies the device and in case that the condition is met I would like the device to stop every thing and don't turn on, right now I set the PIN back to Low and the device turn off over time, the problem is that in that interval the MCUboot starts its executions. Is there a way to stop the device from continuing when there is an error (the button is released) in the board_init() function? I already tried using a return codes 1 and -1.

Also, I would like to modify the MCUboot to implement points 2 (battery and charger verification) and 3 (change upgrade strategy) from the original ticket I submitted. Will I have to modify the MCUboot's main.c file directly on the NCS? Or is there a way in which I can create a new main.c file that can be used by the MCUboot without modifying the one in the NCS?

RE: Modify the MCUboot's booting process

user15146 — Thu, 09 Jun 2022 19:13:16 GMT

[quote user="Erasmo"]I would like to keep the modifications in the git repository and avoid modifying the NCS directly (if possible).[/quote]

I found a different way. Create a file named CMakeLists.txt with this content:

if(CONFIG_GPIO AND DEFINED CONFIG_MCUBOOT)
	zephyr_library()
	zephyr_library_sources(board.c)
endif()

place it in in your board folder, e.g. for the nRF52840DK board it would be: zephyr\boards\arm\nrf52840dk_nrf52840\

Then in the board folder create a file board.c , with something like this:

/*
 * Copyright (c) 2022 Nordic Semiconductor ASA
 *
 * SPDX-License-Identifier: LicenseRef-Nordic-5-Clause
 */

#include <init.h>
#include <drivers/gpio.h>
#include <sys/printk.h>

/* The devicetree node identifier for the "led0" alias. */
#define LED0_NODE DT_ALIAS(led1)

#if DT_NODE_HAS_STATUS(LED0_NODE, okay)
#define LED0	DT_GPIO_LABEL(LED0_NODE, gpios)
#define PIN	DT_GPIO_PIN(LED0_NODE, gpios)
#define FLAGS	DT_GPIO_FLAGS(LED0_NODE, gpios)
#else
/* A build error here means your board isn't set up to blink an LED. */
#error "Unsupported board: led0 devicetree alias is not defined"
#define LED0	""
#define PIN	0
#define FLAGS	0
#endif

static int board_init(const struct device *dev)
{
	int err;
	printk("board_init\n");
	printk("PIN %d\n",PIN);

	static const struct device *led;

	led = device_get_binding(DT_GPIO_LABEL(LED0_NODE, gpios));

	bool led_is_on = false;

	err = gpio_pin_configure(led, PIN, GPIO_OUTPUT_ACTIVE);
	printk("gpio_pin_configure() returned: %d \n",err);
	if (err < 0) {
		return 1;
	}

	err = gpio_pin_set(led, PIN, (int)led_is_on);
	printk("gpio_pin_set() returned: %d \n",err);
	return 0;
}

SYS_INIT(board_init, APPLICATION, CONFIG_APPLICATION_INIT_PRIORITY);

This board_init() function will then be called before the bootloader starts.

We do something similar here, but this is before the main application starts:

https://github.com/nrfconnect/sdk-nrf/blob/v2.0.0/boards/arm/thingy91_nrf9160/adp5360_init.c

https://github.com/nrfconnect/sdk-nrf/blob/v2.0.0/boards/arm/thingy91_nrf9160/CMakeLists.txt

RE: Modify the MCUboot's booting process

user114965 — Wed, 08 Jun 2022 19:59:58 GMT

Hi,

[quote userid="15146" url="~/f/nordic-q-a/88643/modify-the-mcuboot-s-booting-process/371307#371307"]the SYS_INIT can be used. (e.g. placed at the bottom of main.c of MCUBoot, assuming it's too late for your device to do it in your own application).[/quote]

Does the main.c file that you mention is the one located on the NCS' path bootloader/mcuboot/boot/zephyr?

If that is the file, is there a way to create a copy (with my modifications) inside my application's project and just change the file that is going to be used?

I would like to keep the modifications in the git repository and avoid modifying the NCS directly (if possible).

RE: Modify the MCUboot's booting process

user15146 — Wed, 08 Jun 2022 08:13:15 GMT

Hi,

[quote user=""]I would like to know the best way to make this modifications and in the case of the third point if there is a configuration option or example.[/quote]

If you need to run a function at boot, then the SYS_INIT can be used. (e.g. placed at the bottom of main.c of MCUBoot, assuming it's too late for your device to do it in your own application).

[quote user=""]Change the upgrade strategy from swapping the images in the memory slots to just changing the address of the image that it will boot.[/quote]

I'm not seeing any such configs. You can read about the upgrade strategies e.g. here