Booting meta-xilinx boards

Contents

Loading via JTAG

This boot flow requires the use of the Xilinx tools, specifically XSDB and the associated JTAG device drivers. This also requires access to the JTAG interface on the board, a number of Xilinx and third-party boards come with on-board JTAG modules.

XSDB

Start xsdb and connect. Ensure that the target chip is visible.

$ xsdb
xsdb% connect
xsdb% targets

Load Bitstream

(Note: This step is only required for platforms which have a bitstream e.g. MicroBlaze.)

Download the bitstream for the system using XSDB with the fpga -f command. If a bitstream is available from meta-xilinx is will be located in the deploy/images/<machine-name>/ directory.

xsdb% fpga -f download.bit

Load U-Boot (MicroBlaze)

Download u-boot.elf to the target CPU via the use of XSDB.

xsdb% targets -set -filter {name =~ "MicroBlaze*"}
xsdb% rst
xsdb% dow u-boot.elf
xsdb% con

Load U-Boot (Zynq)

Ensure the board is configured to boot from JTAG. The Zynq platform requires the loading of SPL first, this can be done by loading the u-boot-spl.bin and executing it at location 0x0. u-boot-spl.bin is not output to the deploy directory by default, it can be obtained from the work directory for U-Boot (git/spl/u-boot-spl.bin) or can be extracted from boot.bin using dd if=boot.bin of=u-boot-spl.bin bs=1 skip=2240.

xsdb% targets -set -filter {name =~ "ARM*#0"}
xsdb% dow -data u-boot-spl.bin 0x0
xsdb% rwr pc 0x0
xsdb% con

On the UART console the following should appear, indicating SPL was loaded.

U-Boot SPL 2016.01
Trying to boot from unknown boot device
SPL: Unsupported Boot Device!
SPL: failed to boot from all boot devices
### ERROR ### Please RESET the board ###

Once SPL has loaded U-Boot can now be loaded into memory and executed. Download u-boot.elf to the target.

xsdb% stop
xsdb% dow u-boot.elf
xsdb% con

U-Boot Console

U-Boot will load and the console will be available on the UART interface.

...
Hit any key to stop autoboot: 0
U-Boot>

Kernel, Root Filesystem and Device Tree

Whilst it is possible to load the images via JTAG this connection is slow and this process can take a long time to execute (more than 10 minutes). If your system has ethernet it is recommended that you use TFTP to load these images using U-Boot.

Once U-Boot has been loaded, pause the execution using XSDB and use the dow command to load the images into the targets memory. Once the images are loaded continue the execution and return to the U-Boot console.

MicroBlaze (kc705-microblazeel):

xsdb% stop
xsdb% dow -data linux.bin.ub 0x85000000
xsdb% dow -data core-image-minimal-kc705-microblazeel.cpio.gz.u-boot 0x86000000
xsdb% dow -data kc705-microblazeel.dtb 0x84000000
xsdb% con

Zynq:

xsdb% stop
xsdb% dow -data uImage 0x2000000
xsdb% dow -data core-image-minimal-<machine name>.cpio.gz.u-boot 0x3000000
xsdb% dow -data <machine name>.dtb 0x2A00000
xsdb% con

Booting via U-Boot

At the U-Boot console use the bootm command to execute the kernel.

MicroBlaze (kc705-microblazeel):

U-Boot> bootm 0x85000000 0x86000000 0x84000000

Zynq:

U-Boot> bootm 0x2000000 0x3000000 0x2A00000

Loading via SD

(Note: This section only applies to Zynq and ZynqMP.)

Preparing SD/MMC

Setup the card with the first partition formatted as FAT16. If you intend to boot with the root filesystem located on the SD card, also create a second partition formatted as EXT4.

It is recommended that the first partition be at least 64MB in size, however this value will depend on whether using a ramdisk for the root filesystem and how large the ramdisk is.

This section describes how to manually prepare and populate an SD card image. There are automation tools in OpenEmbedded that can generate disk images already formatted and prepared such that they can be written directly to a disk. Refer to the Yocto Project Development Manual for more details: http://www.yoctoproject.org/docs/current/dev-manual/dev-manual.html#creating-partitioned-images

Installing U-Boot (Zynq)

Add the following files to the first partition:

  • boot.bin
  • u-boot.img

Installing U-Boot (ZynqMP)

Add the following files to the first partition:

  • boot.bin
  • u-boot.bin

Installing Kernel and Device Tree (Zynq)

Add the following files to the first partition:

  • uImage
  • <machine name>.dtb

Installing Kernel and Device Tree (ZynqMP)

Add the following files to the first partition:

  • Image
  • <machine name>.dtb

Install ARM Trusted Firmware (ZynqMP)

Add the following file to the first partition:

  • atf-uboot.ub

Install U-boot environment file (ZynqMP)

Add the following file to the first partition:

  • uEnv.txt

Installing Root Filesystem

If using a ramdisk also add the .cpio.gz.u-boot type of root filesystem image to the first partition.

  • core-image-minimal-<machine name>.cpio.gz.u-boot

If using the SD card as the root filesystem, populate the second partition with the content of the root filesystem. To install the root filesystem extract the corresponding tarball into the root of the second partition (the following command assumes that the second partition is mounted at /media/root).

tar x -C /media/root -f core-image-minimal-<machine name>.tar.gz

U-Boot Configuration File

Also create the file uEnv.txt on the first partition of the SD card partition, with the following contents. Replacing the names of files where appropriate.

kernel_image=uImage
devicetree_image=<machine name>.dtb

If using a ramdisk root filesystem setup the ramdisk_image variable.

ramdisk_image=core-image-minimal-<machine name>.cpio.gz.u-boot

If using the SD card as the root filesystem setup the kernel boot args, and uenvcmd variable.

bootargs=root=/dev/mmcblk0p2 rw rootwait
uenvcmd=fatload mmc 0 0x3000000 ${kernel_image} && fatload mmc 0 0x2A00000 ${devicetree_image} && bootm 0x3000000 - 0x2A00000

Booting

Insert the SD card and connect UART to a terminal program and power on the board. (For boards that have configurable boot jumper/switches ensure the board is configured for SD).

Initially U-Boot SPL will load, which will in turn load U-Boot. U-Boot will use the uEnv.txt to automatically load and execute the kernel.

Loading via TFTP

(Note: This boot flow requires ethernet on the baord and a TFTP server)

Boot your system into U-Boot, using one of boot methods (e.g. JTAG, SD, QSPI).

Kernel, Root Filesystem and Device Tree

Place the following images into the root of the TFTP server directory:

  • core-image-minimal-<machine name>.cpio.gz.u-boot
  • uImage (Zynq) or linux.bin.ub (MicroBlaze)
  • <machine name>.dtb

Booting via U-Boot

The serial console of the target board will display the U-Boot console. Configure the ipaddr and serverip of the U-Boot environment.

U-Boot> set serverip <server ip>
U-Boot> set ipaddr <board ip>

Using the U-Boot console; load the Kernel, root filesystem and the DTB into memory. And then boot Linux using the bootm command. (Note the load addresses will be dependant on machine used)

MicroBlaze (kc705-microblazeel):

U-Boot> tftpboot 0x85000000 linux.bin.ub
U-Boot> tftpboot 0x86000000 core-image-minimal-kc705-microblazeel.cpio.gz.u-boot
U-Boot> tftpboot 0x84000000 kc705-microblazeel.dtb
U-Boot> bootm 0x85000000 0x86000000 0x84000000

Zynq:

U-Boot> tftpboot 0x2000000 uImage
U-Boot> tftpboot 0x3000000 core-image-minimal-<machine name>.cpio.gz.u-boot
U-Boot> tftpboot 0x2A00000 <machine name>.dtb
U-Boot> bootm 0x2000000 0x3000000 0x2A00000

U-Boot will prepare the Kernel for boot and then it will being to execute.

...
Starting kernel...