NUVOTON NUC970 NUC980系列微控制器基于系统设计的应用指南说明书

2024年10月25日发(作者：乐正绿海)

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OTA Update on U-Boot

Application Note for NUC970/NUC980 Series

Document Information

Abstract

Apply to

The information described in this document is the exclusive intellectual property of

Nuvoton Technology Corporation and shall not be reproduced without permission from Nuvoton.

Nuvoton is providing this document only for reference purposes of NuMicro microcontroller based system design.

Nuvoton assumes no responsibility for errors or omissions.

All data and specifications are subject to change without notice.

For additional information or questions, please contact: Nuvoton Technology Corporation.

This application note introduces how to do OTA firmware update on

u-boot.

NUC970/NUC980 series.

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Table of Contents

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OVERVIEW .............................................................................................................................. 3

NUWRITER .............................................................................................................................. 5

2.1

Related Resources ...................................................................................................................... 5

3 FIRMWARE UPDATE APPLICATION - FWUPDATE ............................................... 6

3.1

Compile and Program fwupdate ............................................................................................... 6

3.2

Use fwupdate to Write Image on Flash .................................................................................... 6

4 OTA_UPDATE COMMAND 8

4.1

Create ota_update.c .................................................................................................................... 8

4.2

Create check_crc.h and check_crc.c ..................................................................................... 11

4.2.1

Create check_crc.h ........................................................................................................................ 11

4.2.2

Create check_crc.c ........................................................................................................................ 11

4.3

Create crc_checksum.h and crc_checksum.c ...................................................................... 12

4.3.1

Create crc_checksum.h ................................................................................................................ 12

4.3.2

Create crc_checksum.c ................................................................................................................ 12

4.4

Compile u-boot and Linux Kernel ........................................................................................... 13

4.5

Modify ............................................................................................................................. 13

CONCLUSION ...................................................................................................................... 15

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1 Overview

This application note introduces how to do OTA firmware update on u-boot space. In the past,

everyone usually updates firmware on user space. If a device is powered off during updating,

it will cause damage to the device kernel. Therefore, Nuvoton provides a method to keep the

original Linux kernel complete, and checks whether the new firmware update is completed or

not.

This method separates Flash into four mtdpartitions: u-boot, original Linux kernel, new Linux

kernel, and root filesystem, as shown in Figure 1-1. You need to pack the new Linux kernel into

package by NuWriter and download the package to the root filesystem. Then use fwupdate to

write the package to Flash and use ota_update to update the Linux kernel. After ota_update

in u-boot environment variable is set up, it will be executed and do OTA firmware update.

Figure 1-1 Flash Partition

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The OTA update flowchart is shown in Figure1-2. First, you need to pack the new Linux kernel

by NuWriter. When NuWriter packs the Linux kernel, it will attach a header file such that the

fwupdate writes the package to a specified Flash address.

ota_update reads and compares Img1’s and Img2’s image header file to decide if firmware will

be updated or not. If Img1 and Img2 are the same, system will not be updated and will boot

from Img1. If Img1 is damaged or system needs to be updated, ota_update will check Img2

checksum to ensure Img2 is completed. If Img2 is completed, ota_update will copy Img2 to

Img1’s Flash address and reboot. However, if the Img1 and Img2 are all damaged, system will

not boot up, then stop booting at u-boot to avoid rebooting repeatedly, and send a warning

message.



fwupdate: A Linux command to write package to Flash

ota_update: A u-boot command to update the Linux kernel

Img1: The original Linux kernel image

Img2: The new Linux kernel image

CRC checksum: Used to check the image completeness

Figure1-2 ota_update Flowchart

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2 NuWriter

The NuWriter is a programing tool provided by Nuvoton. The NuWriter application and firmware

code are open sourced, and user can add new features or develop new user interfaces per

user’s application. The NuWriter tool uses chip’s USB ISP mode with windows application on

the PC by USB device for data transmission to program the image file to different storage

devices. On-board ROM device includes NAND Flash, SPI Flash, eMMC/SD, and SPI NAND

Flash.

2.1 Related Resources

Refer to Pack mode section in NuWriter User Manual for how to pack Linux kernel. You can

download the NuWriter User Manual from Nuvoton’s official website:

 NuWriter for NUC970 User Manual can be found in N9H30_emWin_Non-

OS_BSP_v1.04: /resource-

?tp_GUID=SW1827

 NuWriter source code for NUC970 series:

/OpenNuvoton/NUC970_NuWriter

 NuWriter for NUC980 User Manual can be found in NUC980_Linux-

4.4_BSP_: /resource-

?tp_GUID=SW1824

 NuWriter source code for NUC980 series:

/OpenNuvoton/NUC980_NuWriter

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3 Firmware Update Application - fwupdate

Nuvoton provides fwupdate to write package generated by NuWriter to Flash. The package

can include uboot, Linux kernel, and .

However, only Linux kernel is included here.

Refer to Nuvoton NUC970/NUC980 Application Note “Create Root Filesystem on Flash” for

how to create root filesystem on Flash.

3.1 Compile and Program fwupdate

The fwupdate can be found in the nuc980bsp:

~/NUC970_Buildroot/nuc980bsp/application/demos/fwupdate

Compile fwupdate through make command.

~/NUC970_Buildroot/nuc980bsp/application/demos/fwupdate$ make

It will generate an fwupdate binary file, and copy it to the target folder.

~/NUC970_Buildroot/nuc980bsp/application/demos/fwupdate$ cp fwupdate

/home/user/Buildroot/NUC980_IIOT/NUC970_Buildroot/output/target/usr/bin/

Compile and program Linux kernel to device, and use fwupdate command.

3.2 Use fwupdate to Write Image on Flash

fwupdate application usage:

-p, --pack, path of pack file

-w, --whole, name of MTD partition and this partition must contain whole Flash address

-h, --help, help

Use fwupdate command in the device terminal to write “New_Pack_Image” package to Flash.

The Flash address can be defined in NuWriter. “New_Pack_Image” package file is created by

NuWriter pack mode. Refer to the “Modify ” section. The name “WHOLE” is one of MTD

partition can be defined in u-boot environment variable.

$fwupdate –p New_Pack_Image –w WHOLE

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Figure 3-1 NuWriter Pack Mode

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4 ota_update Command on U-Boot

ota_update checks the two image’s CRC number. If the two CRC numbers are not the same,

ota_update will check new Linux kernel completeness for firmware update. ota_update

consists of five C language files in the u-boot.



ota_update.c

check_crc.c

check_crc.h

crc_checksum.c

crc_checksum.h

Add the following text in Makefile to compiling function above.

Open the Makefile in common folder.

~/NUC970_Buildroot/output/build/uboot-master/common$ gedit Makefile

Add the following code:

obj-y += ota_update.o

obj-y += check_crc.o

obj-y += crc_checksum.o

4.1 Create ota_update.c

Go to the /Buildroot/NUC980_IIOT/NUC970_Buildroot/output/build/uboot-master/common

folder and create a file named The code is shown below:

#include

#include "check_crc.h"

#include "crc_checksum.h"

#include

#define SPI_MODE_0

extern int check_crc(char* addr1, char* addr2);

extern int crc_checksum(char* image_number, char* image_addr);

extern int do_reset(cmd_tbl_t *cmdtp, int flag, int argc, char * const argv[]);

(0|0)

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extern int do_bootm(cmd_tbl_t *cmdtp, int flag, int argc, char * const argv[]);

//argv[0]=ota_update argv[1]=image1_ram_offset argv[2]=image2_ram_offset

argv[3]=image1_flash_offset argv[4]=image2_flash_offset argv[5]=image_size

static int ota_update(cmd_tbl_t *cmdtp, int flag, int argc, char * const argv[]){

int check_crc_flag = 0;

char* bootm[]={"bootm",argv[1]};

int otaupdate_flag=0;//0 boot from image1; 1 image 1 and 2 are damaged;

if(argc!=6)

check_crc_flag=check_crc(argv[1],argv[2]);

if(check_crc_flag==1)

{

}

else

{

printf("image 1's crc and 2's crc are different, check image 2 ...n");

if(crc_checksum("2",argv[2]))

{

printf("CRC check is the same, check image 1 ...n");

if(crc_checksum("1",argv[1]))

{

}

else

{

}

printf("Image 1 is damaged, check image 2 ...n");

if(crc_checksum("2",argv[2]))

{

}

else

{

}

printf("Image 1 and 2 are damagedn");

otaupdate_flag=1;

printf("Prepare copy image 2 to 1n");

otaupdate_flag=0;

printf("Boot from Image 1n");

do_bootm(cmdtp,0,2,bootm);

return CMD_RET_USAGE;

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}

else

{

}

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}

printf("Prepare copy image 2 to 1n");

otaupdate_flag=0;

printf("Image 2 is damaged, check Image 1n");

if(crc_checksum("1",argv[1]))

{

}

else

{

}

printf("Image 1 and 2 are damagedn");

otaupdate_flag=1;

printf("Boot from Image 1n");

do_bootm(cmdtp,0,2,bootm);

return otaupdate_flag;

U_BOOT_CMD(

ota_update,6,0,ota_update,"Check two image if update the kernel or not",

"ota_update [addr1] [addr2]n"

" addr1 is original kernel ram addressn"

" addr2 is new kernel ram addressn"

);

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4.2 Create check_crc.h and check_crc.c

4.2.1 Create check_crc.h

Go to the /Buildroot/NUC980_IIOT/NUC970_Buildroot/output/build/uboot-master/common

folder and create a file named as check_crc.h. The code is shown below:

int check_crc(char* addr1, char* addr2);

4.2.2 Create check_crc.c

check_crc will read two image’s header to check CRC number if they are the same or not. This

function need to input two RAM address, then it will return CRC number the same or not.

Go to the /Buildroot/NUC980_IIOT/NUC970_Buildroot/output/build/uboot-master/common

folder and create a file named as

The code is shown below:

#include

#include "crc_checksum.h"

#include "check_crc.h"

int do_spi_flash_probe(int argc, char * const argv[]);

int do_spi_flash_read_write(int argc, char * const argv[]);

int check_crc(char* addr1, char* addr2)

{

}

ulong addr;

addr = simple_strtoul(addr1, NULL, 16);

void *hdr = (void *)map_sysmem(addr, 0);

ulong Image1crc=image_get_hcrc(hdr);

printf("Image 1 crc=%ldn",Image1crc);

addr = simple_strtoul(addr2, NULL, 16);

hdr = (void *)map_sysmem(addr, 0);

ulong Image2crc=image_get_hcrc(hdr);

printf("Image 2 crc=%ldn",Image2crc);

if(Image1crc==Image2crc)

return 1;

return 0;

else

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4.3 Create crc_checksum.h and crc_checksum.c

4.3.1 Create crc_checksum.h

Go to the /Buildroot/NUC980_IIOT/NUC970_Buildroot/output/build/uboot-master/common

folder and create a file named as crc_checksum.h. The code is shown below:

int crc_checksum(char* image_number, char* image_addr);

4.3.2 Create crc_checksum.c

crc_checksum will use CRC32 to check the whole image. crc_checksum needs to input image

number and RAM address, and then it will return the image is complete or not.

Go to the /Buildroot/NUC980_IIOT/NUC970_Buildroot/output/build/uboot-master/common

folder and create a file named as The code is shown below:

#include

#include "crc_checksum.h"

int crc_checksum(char* image_number, char* image_addr)

{

}

ulong addr;

addr = simple_strtoul(image_addr, NULL, 16);

void *hdr = (void *)map_sysmem(addr, 0);

int hcrc_flag=image_check_hcrc(hdr);

if(hcrc_flag==0){

}

int dcrc_flag=image_check_dcrc(hdr);

printf("Image %s Header Check =%dn",image_number,hcrc_flag);

printf("Image %s Data Check =%dn",image_number,dcrc_flag);

if((hcrc_flag+dcrc_flag)==2){

}

else{

}

printf("Image %s Check Failn",image_number);

return 0;

printf("Image %s Check Okn",image_number);

return 1;

printf("Image %s Check Failn",image_number);

return 0;

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4.4 Compile u-boot and Linux Kernel

Compile u-boot under uboot-master folder and program it to device.

~/NUC970_Buildroot/output/build/uboot-master$ make

Compile Linux kernel under Buildroot folder and program it to device.

~/NUC970_Buildroot$ make

4.5 Modify

Please refer to the Application Note “Create Root Filesystem on Flash” for how the u-boot

environment variable is set up. You can modify shown below to execute ota_update.

Besides, there is a difference between NOR Flash and NAND Flash. NAND Flash needs to use

nand command and NOR Flash needs to use sf command.



image1_flash_offset: Img1 Flash offset

image2_flash_offset: Img2 Flash offset

image_size: kernel image’s size

image1_ram_offset: the RAM address offset which is put Img1

image2_ram_offset: the RAM address offset which is put Img2

loadkernel1, loadkernel2: read Flash to RAM

eraseflash: erase Img1 Flash

copykernel: copy Img2 to Img1 on Flash

NAND Flash is shown below:

baudrate=115200

bootdelay=1

stderr=serial

stdin=serial

stdout=serial

image1_flash_offset=0x200000

image2_flash_offset=0x800000

image_size=0x600000

image1_ram_offset=0x7fc0

image2_ram_offset=0x800000

loadkernel1=nand read ${image1_ram_offset} ${image1_flash_offset} ${image_size}

loadkernel2=nand read ${image2_ram_offset} ${image2_flash_offset} ${image_size}

eraseflash=nand erase ${image1_flash_offset} ${image_size}

copykernel=nand write ${image2_ram_offset} ${image1_flash_offset} ${image_size}

bootcmd=run loadkernel1;run loadkernel2;if ota_update ${image1_ram_offset}

${image2_ram_offset} ${image1_flash_offset} ${image2_flash_offset} ${image_size};then run

eraseflash;run copykernel;reset;fi;

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bootargs=noinitrd root=/dev/mtdblock4 rootfstype=yaffs2 rootflags=inband-tags

console=ttyS0 rdinit=/sbin/init mem=64M

mtdparts=nand0:0x2000000@0x0(WHOLE),0x200000@0x0(u-

boot),0x600000@0x200000(kernel1),0x600000@0x800000(kernel2),-(user) ignore_loglevel

NOR Flash is shown below:

baudrate=115200

bootdelay=1

stderr=serial

stdin=serial

stdout=serial

image1_flash_offset=0x200000

image2_flash_offset=0x800000

image_size=0x600000

image1_ram_offset=0x7fc0

image2_ram_offset=0x800000

setspi=sf probe 0 30000000

loadkernel1=sf read ${image1_ram_offset} ${image1_flash_offset} ${image_size}

loadkernel2=sf read ${image2_ram_offset} ${image2_flash_offset} ${image_size}

eraseflash=sf erase ${image1_flash_offset} ${image_size}

copykernel=sf write ${image2_ram_offset} ${image1_flash_offset} ${image_size}

bootcmd=run setspi;run loadkernel1;run loadkernel2;if ota_update ${image1_ram_offset}

${image2_ram_offset} ${image1_flash_offset} ${image2_flash_offset} ${image_size};then run

eraseflash;run copykernel;reset;fi;

bootargs=noinitrd root=/dev/mtdblock4 rw rootfstype=jffs2 console=ttyS0 rdinit=/sbin/init

mem=64M mtdparts=m25p80:0x2000000@0x0(WHOLE),0x200000@0x0(u-

boot),0x600000@0x200000(kernel1),0x600000@0x800000(kernel2),-(user) ignore_loglevel

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5 Conclusion

The ota_update function updates Linux kernel on u-boot to keep the original kernel work

normally until the new kernel is verified completely. This can avoid copying the damaged kernel

to original kernel. If the original kernel is damaged because of updating failed, ota_update will

retry updating the new kernel until update is successful. If you want to update the whole image

including u-boot, u-boot environment, Linux kernel, and root filesystem, you still can use

NuWriter and fwupdate to update. You can pack u-boot, u-boot environment, Linux kernel, root

filesystem as a package, and use fwupdate command to write the package into Flash. Updating

the whole kernel must be performed carefully because it may damage the original image.

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Revision History

Date Revision

2021.07.18 1.00

2023.04.25 1.01

May 25, 2021

Description

1. Initially issued.

2. Add more descriptions in section 3

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Important Notice

Nuvoton Products are neither intended nor warranted for usage in systems or equipment, any malfunction

or failure of which may cause loss of human life, bodily injury or severe property damage. Such

applications are deemed, “Insecure Usage”.

Insecure usage includes, but is not limited to: equipment for surgical implementation, atomic energy

control instruments, airplane or spaceship instruments, the control or operation of dynamic, brake or

safety systems designed for vehicular use, traffic signal instruments, all types of safety devices, and other

applications intended to support or sustain life.

All Insecure Usage shall be made at customer’s risk, and in the event that third parties lay claims to

Nuvoton as a result of customer’s Insecure Usage, customer shall indemnify the damages and liabilities

thus incurred by Nuvoton.

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