Petalinux boot commands uboot and kernel

[peterjohn]

Hi, 

I just have a look at the command line reference guide UG 1157. I guess both the following commands download the respective image on the physical board using JTAG. What is the difference between downloading u-boot image and kernel image ? 

$ petalinux-boot --jtag --u-boot
$ petalinux-boot --jtag --kernel

[patocarr]

Hi @peterjohn 

  The --u-boot version only downloads the bootloader, leaving it up to you to load the kernel through other means (i.e. TFTP or from flash). The --kernel switch loads both, the bootloader and the kernel over JTAG, and then runs them.

Thanks,

-Pat

[stephenm]

@patocarr is correct. if you want to see the difference just use the --tcl script.tcl and you will see the difference

[peterjohn]

Hi, 

This command "$ petalinux-boot --jtag --u-boot" downloads the following in ZYNQ. 

- fsbl images/linux/zynq_fsbl.elf
- U-Boot images/linux/u-boot.elf

Similarly this command "$ $ petalinux-boot --jtag --kernel" downloads the following in ZYNQ. 

- fsbl images/linux/zynq_fsbl.elf
- DTB images/linux/system.dtb
- kernel images/linux/zImage

I am wondering what is included in these files ? I mean which file contains bit file ? and what is included in zImage ? 

[patocarr]

Hi @peterjohn 

  It doesn't look like the --kernel option is loading the U-Boot as I pointed out above. Perhaps for Zynq is different than for ZynqMP. The zImage contains the kernel image and rootfs. The bitstream is loaded through the "fpga" command; you didn't see it in the .tcl output?

Thanks,

-Pat

[peterjohn]

@patocarr 

Thanks for reply. This is what I was wondering that --kernel does not download u-boot for ZYNQ. If we need to download u-boot that it has to be loaded through --u-boot. Both commands --kernel and --u-boot does not download FPGA bitstream. The FPGA bitstream has to be loaded through --fpga command. 

I also have looked at level 2 and level 3 prebuilt commands for ZYNQ. They actually does all what we need to run an application physically on the board.  

$ petalinux-boot --jtag --prebuilt 2

The level 2 command downloads FPGA bitstream, FSBL and U-boot. 

$ petalinux-boot --jtag --prebuilt 3

The level 3 command downloads FPGA bitstream, FSBL, U-boot and Kernel on target board.