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Introduction

Expand

title	Starting with Petalinux Version 2020.1...

, the industry standard "distro boot" boot flow for U-boot has been implemented as default by Xilinx. (see xilinx-wiki.atlassian "Using Distro Boot With Xilinx U-Boot")

The distro boot functionality is implemented as an extension of the existing U-Boot bootcmd functionality in U-Boot. It extends its functionality by redirecting the call to bootcmd to a call to the distro_bootcmd variable.

Code Block

language	bash
theme	Midnight

bootcmd=run distro_bootcmd

The distro_bootcmd variable typically contains a sequence of commands that scans a pre-defined list of potential boot targets in search of boot collateral as shown below.

Code Block

language	bash
theme	Midnight

scriptaddr=0x3000000
script_offset_f=fc0000
script_size_f=0x40000

boot_targets=qspi jtag mmc0 mmc1 qspi nand nor usb0 usb1 pxe dhcp
distro_bootcmd=for target in ${boot_targets}; do run bootcmd_${target}; done

bootcmd_qspi=sf probe 0 0 0 && sf read ${scriptaddr} ${script_offset_f} ${script_size_f} && echo QSPI: Trying to boot script at ${scriptaddr} && source ${scriptaddr}; echo QSPI: SCRIPT FAILED: continuing...;
bootcmd_mmc0=devnum=0; run mmc_boot
mmc_boot=if mmc dev ${devnum}; then devtype=mmc; run scan_dev_for_boot_part; fi

The boot_targets list is defined in the platform definition in the U-The boot_targets list is defined in the platform definition in the U-Boot source tree.

Depending on the specifics of the target platform, the distro boot infrastructure can either use the boot_targets list to explicitly find specific boot collateral (eg. hard-coded loading once a valid boot target is located) or it can be used to locate some kind of decoupled configuration information.

Boot Method Precedence

The order of precedence for searching for boot components is as follows

extlinux.conf file (located in /extlinux/ or /boot/extlinux/)
boot.scr file + image.ub file
boot.scr file + individual files (Image, system.dtb, etc.)

In absence of a valid extlinux.conf file, U-Boot will scan the boot_targets list looking for a file named boot.scr.uimg or boot.scr (in that order) and run any commands located in the script file. If your environment requires a different sequence of commands or behaviour, you can edit the boot.scr file to suit your needs.

Using the boot.src method

Install u-boot-tools on Linux OS

Before using the mkimage function, the u-boot-tools needs to be installed.

Code Block

language	bash
theme	Midnight

sudo apt-get update
sudo apt install u-boot-tools

Modifying an existing

Generate boot.script file from boot.scr file

For the modification of the boot.scr file convert the existing boot.scr file into an boot.script file:

Code Block

language	bash
theme	Midnight

dd if=boot.scr of=boot.script bs=72 skip=1

Modifying boot.script file

Modify Than modify the boot.script file based on your needs. For example, when booting image.ub from SD card, USB or QSPI flash, the following boot.script file should work after conversion into an boot.scr file. The boot.scr file could be located on all working boot_targets.

Code Block

language

Code Block

language	bash
theme	Midnight
title	example boot.script file

# This is a boot script for U-Boot
# Generate boot.scr:
# mkimage -c none -A arm -T script -d boot.script boot.scr
#
# Generate boot.script (for modifications in boot.scr):
# dd if=boot.scr of=boot.script bs=72 skip=1
#
################
imageub_addr=0x10000000
# 
imageub_flash_addr=0x200000
imageub_flash_size=0xD90000

echo [TE_BOOT-01] Trenz Boot-file version 1.0 (development);
echo [TE_BOOT-10] Found boot.scr in device: ${target}
echo [TE_BOOT-11] Chosen Bootmode is ${modeboot} from boot_targets=${boot_targets};
echo [TE_BOOT-11] Use RAM Address ${imageub_addr} for linux image;


for boot_target in ${boot_targets};
do

	#echo [TE_BOOT-11] currently trying to load from ${target};
	#echo [TE_BOOT-12] boot_target = ${boot_target};
	#echo [TE_BOOT-13] devtype = ${devtype}; 
	#echo [TE_BOOT-14] devnum = ${devnum}; 
	#echo [TE_BOOT-15] distro_bootpart = ${distro_bootpart}; 
	#echo [TE_BOOT-16] boot_prefixes = ${boot_prefixes}; 
	#echo [TE_BOOT-17] source =  ${prefix}${script};
	
	# Boot target is mmc0 or usb0: image.ub on mmc0 or usb0
	if test "${boot_target}" = "${devtype}0"; then
		if test -e ${devtype} 0:${distro_bootpart} /image.ub; then
			echo [TE_BOOT-20] boot_target is ${boot_target}. Found image.ub on ${devtype}0:${distro_bootpart} ;
			fatload ${devtype} 0:${distro_bootpart} ${imageub_addr} image.ub;
			bootm ${imageub_addr};
		fi
	fi
	# Boot target is mmc1 or usb1: image.ub on mmc1 or usb1
	if test "${boot_target}" = "${devtype}1"; then
		if test -e ${devtype} 1:${distro_bootpart} /image.ub; then
			echo [TE_BOOT-21] boot_target is ${boot_target}. Found image.ub on ${devtype}1:${distro_bootpart};
			fatload ${devtype} 1:${distro_bootpart} ${imageub_addr} image.ub;
			bootm ${imageub_addr};
		fi
	fi
	# Boot target is qspi: image.ub on qspi; image.ub is included in BOOT.bin
	if test "${boot_target}" = "qspi"; then
		echo [TE_BOOT-30] Try to use image.ub from ${boot_target}, load image.ub from qspi-flash address ${imageub_flash_addr}; 
		echo [TE_BOOT-30] max. image.ub size is ${imageub_flash_size} ;
		sf probe 0 0 0;
		sf read ${imageub_addr} ${imageub_flash_addr} ${imageub_flash_size};
		bootm ${imageub_addr};
	fi
done

Info

title	Note

The alias name ${devnum}, used in Xilinx default files, does not work in all variants tested, therefore the ${devtype} boot_targets were split up

Generate boot.scr file from boot.script file

Please remember that the boot.script file needs to be converted back into the boot.scr file after the edits are complete

Code Block

language	bash
theme	Midnight

mkimage -c none -A arm -T script -d boot.script boot.scr

Distro Boot in SD-Boot mode

bootcmd_mmc0=devnum=0; run mmc_boot mmc_boot=if mmc dev ${devnum}; then devtype=mmc; run scan_dev_for_boot_part; fi

Variant 2 (Boot.bin on SD card, image.ub and boot.scr on USB):

Copy image.ub on SD-Card.
- use files from (<project folder>/_binaries_<Article Name>)/boot_linux from generated binary folder,see: Get prebuilt boot binaries
- or use prebuilt file location, see <design_name>/prebuilt/readme_file_location.txt
Copy boot.scr and Boot.bin on USB Stick
Set Boot Mode to SD-Boot.
- Depends on Carrier, see carrier TRM.
Insert SD-Card in SD-Slot.
Insert USB-Stick in USB-Slot

Expand

title	Tested Boot combinations with example boot script file for TE0715

Scroll Title

title-position	top
title	Table of possible boot variants in SD-Boot mode

Boot Variants	SD-Card (mmc0)	USB-Stick (usb0)	QSPI-Flash	Comments
Variant 1	BOOT.

bin^1

bin¹

image.ub

boot.scr

Init.sh

--

recommended workflow

Variant 2

BOOT.

bin^1

bin¹

image.ub

Init.sh

BOOT.

bin^2

bin²	used boot.scr from QSPI-Flash and image.ub from SD card
Variant 3	BOOT.

bin^1

bin¹

boot.scr

Init.sh

BOOT.

bin^2

bin²	used boot.scr from SD card and image.ub from QSPI-Flash
Variant 4	BOOT.

bin^1

bin¹

image.ub

Init.sh

BOOT.

bin^3

bin³	used boot.scr from QSPI-Flash and image.ub from SD card

Scroll Title

title-position	top
anchor	BOOT.bin in SD-Boot
title	Possible content of BOOT.bin files for qspi flash or sd/usb devices

File name	BOOT.

bin^1

bin¹	BOOT.

bin^2

bin²	BOOT.

bin^3

bin³	QSPI Flash Offset Address	RAM Load Address
fsbl.elf	x	x	x	--	NA
test_board.bit	x	x	x	--	NA
u-boot.elf	x	x	x	--	NA
image.ub		x		0x200000	0x10000000
boot.scr		x	x	0xfc0000	0x3000000

Info

title	Note

When booting from a QSPI device, care must be taken to maintain a very specific scheme for where files are located both in the nonvolatile flash device as well as where they are loaded into DDR prior to hand-off to the robust operating system.

Booting from SD card as described in

Variant 1

Copy

(Boot.bin, image.ub

,

and boot.scr on SD card):

Copy image.ub, boot.scr and Boot.bin on SD-Card.
- use files from (<project folder>/_binaries_<Article Name>)/boot_linux from generated binary folder,see: Get prebuilt boot binaries
- or use prebuilt file location, see <design_name>/prebuilt/readme_file_location.txt
Set Boot Mode to SD-Boot.
- Depends on Carrier, see carrier TRM.
Insert SD-Card in SD-Slot.

Code Block

language	bash
theme	Midnight
title	example: u-boot printenv for TE0715

Distro Boot in QSPI-Boot mode

USB-

Expand

title	Tested Boot combinations with example boot script file for TE0715

Scroll Title

title-position	top
title	Table of possible boot variants in QSPI-Boot mode

Boot Variants	SD-Card (mmc0)	USB-

SD-Card (mmc0)

Stick (usb0)

QSPI-Flash

Comments

Variant 1

--

BOOT.bin²

zynq_fsbl_flash

Boot only from QSPI flash

Variant 2

image.ub

boot.scr

BOOT.bin¹

zynq_fsbl_flash

used boot.scr and image.ub from SD card

Variant 3

BOOT.bin¹

image.ub

BOOT.bin³

zynq_fsbl_flash

used boot.scr from QSPI-Flash and image.ub from SD card

Scroll Title

title-position	top
anchor	BOOT.bin in QSPI-Boot
title	Possible content of BOOT.bin files for qspi flash or sd/usb devices

File name	BOOT.bin¹	BOOT.bin²	BOOT.bin³	QSPI Flash Offset Address	RAM Load Address
fsbl.elf	x	x	x	--	NA
test_board.bit	x	x	x	--	NA
u-boot.elf	x	x	x	--	NA
image.ub		x		0x200000	0x10000000
boot.scr		x	x	0xfc0000	0x3000000

Info

title	Note

When booting from a QSPI device, care must be taken to maintain a very specific scheme for where files are located both in the nonvolatile flash device as well as where they are loaded into DDR prior to hand-off to the robust operating system.

Booting from SD card as described in Variant 1

Variant 1 (Boot.bin on QSPI Flash and image.ub and boot.scr on SD):

Connect JTAG and power on carrier with module (boot mode set to SD boot and no SD card is inserted)
Open Vivado Project with "vivado_open_existing_project_guimode.cmd" or if not created, create with "vivado_create_project_guimode.cmd"
Type on Vivado TCL Console: TE::pr_program_flash -swapp u-boot
Note: To program with SDK/Vivado GUI, use special FSBL (zynq_fsbl_flash) on setup
optional "TE::pr_program_flash -swapp hello_te0715" possible
Copy boot.scr and image.ub on SD-Card
- use files from (<project folder>/_binaries_<Article Name>)/boot_linux from generated binary folder,see: Get prebuilt boot binaries
- or use prebuilt file location, see <design_name>/prebuilt/readme_file_location.txt
Set boot mode to QSPI-Boot mode and insert SD card.
- Depends on Carrier, see carrier TRM.

Variant 2 (Boot.bin

with

, image.ub and boot.scr on QSPI Flash):

Connect JTAG and power on carrier with module (boot mode set to SD boot and no SD card is inserted)
Open Vivado Project with "vivado_open_existing_project_guimode.cmd" or if not created, create with "vivado_create_project_guimode.cmd"
Type on Vivado TCL Console: TE::pr_program_flash -swapp u-boot
Note: To program with SDK/Vivado GUI, use special FSBL (zynq_fsbl_flash) on setup
optional "TE::pr_program_flash -swapp hello_te0715" possible
Set boot mode to QSPI-Boot mode and start the board.
- Depends on Carrier, see carrier TRM.

Note: When booting from a QSPI device, care must be taken to maintain a very specific scheme for where files are located both in the nonvolatile flash device as well as where they are loaded into DDR prior to hand-off to the robust operating system.

ComponentFlash AddressLoad AddressU-Boot combined image file (image.ub)0x200000

0x10000000

Boot.scr0xfc00000x3000000

Code Snippets for Boot.scr file

Expand

title	image.ub on sd card

Code Block

title
language	bash
theme	Midnight

example: u-boot printenv for TE0715

scriptaddr=0x3000000
script_offset_f=fc0000
script_size_f=0x40000
bootcmd_qspi=sf probe 0 0 0 && sf read ${scriptaddr} ${script_offset_f} ${script_size_f} && echo QSPI: Trying to boot script at ${scriptaddr} && source ${scriptaddr}; echo QSPI: SCRIPT FAILED: continuing...;

Code Snippets for Boot.scr file

image.ub on sd card

	# Boot target is mmc0: image.ub on mmc0
	if test "${boot_target}" = "mmc0"; then
		mmc dev 0
		if test -e mmc 0:${distro_bootpart} /image.ub; then
			echo [TE_BOOT-20] boot_target is ${boot_target}. Found image.ub on mmc0:${distro_bootpart} ;
			fatload mmc 0:${distro_bootpart} ${imageub_addr} image.ub;
			bootm ${imageub_addr};
		fi
	fi
	# Boot target is mmc1: image.ub on mmc1

Expand

title	boot.scr and image.ub on sd card

Code Block

language	bash
theme	Midnight
title	image.ub on sd card

	if test "${boot_target}" = "mmc0mmc1"; then
		mmc dev 01
		if test -e ${devtype} 0mmc 1:${distro_bootpart} /image.ub; then
			#fatloadecho [TE_BOOT-21] boot_target is ${devtypeboot_target} 0. Found image.ub on mmc1:${distro_bootpart} ${imageub_addr} image.ub;
			fatload mmc 0;
			fatload mmc 1:${distro_bootpart} ${imageub_addr} image.ub;
			bootm ${imageub_addr};
		fi
	fi
	if test "${boot_target}" = "mmc1"; then
		mmc dev 1
		if test -e ${devtype} 1:${distro_bootpart} /image.ub; then
			#fatload ${devtype} 0:${distro_bootpart} ${imageub_addr} image.ub;
			fatload mmc 1:${distro_bootpart} ${imageub_addr} image.ub;
			bootm ${imageub_addr};
		fi
	fi

Info

title	Note

The alias name ${devnum}, used in Xilinx default files, does not work in all variants tested, therefore the ${devtype} boot_targets were split up

Expand

title	image.ub on sd card or usb

Code Block

language	bash
theme	Midnight
title	image.ub on sd card

	# Boot target is mmc0 or usb0: image.ub on mmc0 or usb0
	if test "${boot_target}" = "${devtype}0"; then
		if test -e ${devtype} 0:${distro_bootpart} /image.ub; then
			echo [TE_BOOT-20] boot_target is ${boot_target}. Found image.ub on ${devtype}

Expand

title	boot.scr and image.ub on sd card or usb

Code Block

language	bash
theme	Midnight
title	image.ub on sd card

	if test "${boot_target}" = "mmc0"; then
		mmc dev 0
		if test -e ${devtype} 0:${distro_bootpart} /image.ub; then
			#fatloadfatload ${devtype} 0:${distro_bootpart} ${imageub_addr} image.ub;
			fatload mmc 0:${distro_bootpart} ${imageub_addr} image.ub;
			bootm ${imageub_addr};
		fi
	fi
	if# testBoot "${boot_targettarget is mmc1 or usb1: image.ub on mmc1 or usb1
	if test "${boot_target}" = "mmc1${devtype}1"; then
		mmc dev 1
		if test -e ${devtype} 1:${distro_bootpart} /image.ub; then
			#fatloadecho [TE_BOOT-21] boot_target is ${devtypeboot_target} 0. Found image.ub on ${devtype}1:${distro_bootpart} ${imageub_addr} image.ub;
			fatload mmc${devtype} 1:${distro_bootpart} ${imageub_addr} image.ub;
			bootm ${imageub_addr};
		fi
	fi

Expandinfo

title	boot.scr and image.ub on sd card

Image Removed

Expand

title	boot.scr and image.ub on usb0

Image Removed

Note

The alias name ${devnum}, used in Xilinx default files, does not work in all variants tested, therefore the ${devtype} boot_targets were split up

Expand

title

Expand

title	boot.scr and image.ub on usb0

Code Block

language	bash
theme	Midnight
title	image.ub on usb0

	if test "${boot_target}" = "usb0"; then
		echo [TE_BOOT-40] Try to use: image.ub from ${boot_target};
		usb start
		#fatload ${devtype} 0:${distro_bootpart} ${imageub_addr} image.ub;
		fatload usb 0:1 ${imageub_addr} image.ub;
		bootm ${imageub_addr};
	fi

boot.scr and image.ub on mmc0

usb0

	# image.ub on usb0
	if test "${boot_target}" = "usb0"; then
		if test -e usb 0:${distro_bootpart} /image.ub

Code Block

language	bash
theme	Midnight
title	example boot.script file

# This is a boot script for U-Boot # Generate boot.scr: # mkimage -c none -A arm -T script -d boot.script boot.scr # ################ imageub_addr=0x10000000 # imageub_flash_addr=0x200000 imageub_flash_size=0xD90000 echo [TE_BOOT-01] Trenz Boot-file version 0.1 (development); echo [TE_BOOT-10] Chosen Bootmode is ${modeboot} from boot_targets=${boot_targets}; echo [TE_BOOT-11] Found boot.scr in device: ${target} for boot_target in ${boot_targets}; do # Boot target is sd card: image.ub on mmc0 if test "${boot_target}" = "mmc0"

; then
			echo [TE_BOOT-20]

Try to use: image.ub from

boot_target is ${boot_target}

; mmc dev 0 if test -e ${devtype} 0

. Found image.ub on usb0:${distro_bootpart}

/image.ub

then


			fatload

${devtype}

usb 0:${distro_bootpart} ${imageub_addr} image.ub;
			bootm ${imageub_addr};
		fi
	fi
	# image.ub on usb1
	if test "${boot_target}" = "

mmc1

usb1"; then

echo [TE_BOOT-21] Try to use:

if test -e usb 1:${distro_bootpart} /image.ub

from ${boot_target};

; then

mmc dev 1 if test -e ${devtype} 1

	echo [TE_BOOT-21] boot_target is ${boot_target}. Found image.ub on usb1:${distro_bootpart}

/image.ub

then


			fatload

${devtype}

usb 1:${distro_bootpart} ${imageub_addr} image.ub;
			bootm ${imageub_addr};
		fi

fi

fi

Expand

title	image.ub on qspi flash

Code Block

language	bash
theme	Midnight
title	image.ub on usb0

	# Boot target is qspi: image.ub on qspi; image.ub is included in BOOT.bin
	if test "${boot_target}" = "qspi"; then
		echo [TE_BOOT-30] Try to use

:

 image.ub from ${boot_target}, load image.ub from qspi-flash address ${imageub_flash_addr}; 
		echo [TE_BOOT-30] max. image.ub size is ${imageub_flash_size} ;
		sf probe 0 0 0;
		sf read ${imageub_addr} ${imageub_flash_addr} ${imageub_flash_size};
		bootm ${imageub_addr};
	fi

done

References

https://xilinx-wiki.atlassian.net/wiki/spaces/A/pages/749142017/Using+Distro+Boot+With+Xilinx+U-Boot#UsingDistroBootWithXilinxU-Boot-BootTargets

https://wiki.ubuntu.com/ARM/EditBootscr

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Table of Contents

Trenz Electronic Documentation

Versions Compared

Old Version 6

New Version 7

Key

Introduction

Using the boot.src method

Install u-boot-tools on Linux OS

Generate boot.script file from boot.scr file

Modifying boot.script file

Generate boot.scr file from boot.script file

Distro Boot in SD-Boot mode

Variant 2 (Boot.bin on SD card, image.ub and boot.scr on USB):

Variant 1

(Boot.bin, image.ub

and boot.scr on SD card):

Distro Boot in QSPI-Boot mode

Variant 1 (Boot.bin on QSPI Flash and image.ub and boot.scr on SD):

Variant 2 (Boot.bin

, image.ub and boot.scr on QSPI Flash):

Code Snippets for Boot.scr file

Code Snippets for Boot.scr file

References