Barebox as alternative to uBoot

[schulz-alexander]

Maybe usefull for bringing up hardware and bootup linux or whatever:

https://www.barebox.org/

[xn--nding-jua]

This is looking promising, especially because U-Boot has dropped the support for the i.MX25. Barebox seems to have devicetree-support for the i.MX25, but the dtsi-file is very short. So this needs more investigation but could be the bootloader for the final system.

[schulz-alexander]

Repo/Branch: https://github.com/OpenMixerProject/barebox/tree/openx32

• load barebox using u-boot, to check the basics
• if this works, then replace u-boot with barebox
• if this works, get the rest working (mmc read, ...)
• get MMU working -> barebox should be faster with MMU
• boot linux
• get USB working -> to enable others to boot the full stack using imx-usb-loader and a prepared USB drive without the need to modify their console
• (optional) implement a driver to get up/down/left/right key working (for menutree)

[schulz-alexander]

current state:

• barebox builds as u-boot bootable image in kernel format (using bootz command)
• u-boot loads barebox ("Starting Kernel ..."), but nothing happens after this ;-)
• need to sort out the serial3 port

[schulz-alexander]

🚀

[schulz-alexander]

Upload via imx-usb-loader works and the lamp turns on via DCD-Table (https://github.com/xn--nding-jua/OpenX32/wiki/Booting)

Next step is to get barebox booting without chainloading via u-boot

[schulz-alexander]

successfully bootet barebox standalone on the X32 🚀

[xn--nding-jua]

Congratulations! How many changes did you make on the barebox-repository. Is it necessary to keep the individual fork or can we take the regular barebox-repository with minimum changes like on U-Boot?

[schulz-alexander]

It's just the serial downloader which works, currently I debug the load from sd card.

I would keep the fork and try to push it upstream some time.

[schulz-alexander]

bootet barebox, mounted sd card, tried to boot the linux kernel

[schulz-alexander]

Current state:

• sd card can be mount
• usb is somewhat working
• framebuffer driver is loaded

Error: Cannot request SDRAM region for stack
imx-esdhc 53fb4000.mmc@53fb4000.of: registered as mmc0
mmc0: detected SD card version 2.0
mmc0: registered mmc0
gpiolib: _gpio_request: gpio-120 (mculed) status -16
gpiolib: _gpio_request: gpio-26 (lamp) status -16
gpiolib: _gpio_request: gpio-124 (reset_surface) status -16
imx-di-rtc 53ffc000.dryice@53ffc000.of: Unlocked unit detected
imxfb imxfb: i.MX Framebuffer driver
fb0: framebuffer console 100x30 activated
fbconsole: registered as fbconsole0-1
fb1: framebuffer console 100x30 activated
fbconsole: registered as fbconsole1-1
malloc space: 0x8de00000 -> 0x8fdfffff (size 32 MiB)
environment load /dev/env0: No such file or directory
Maybe you have to create the partition.

Hit any to stop autoboot:    1
boot: No such file or directory
barebox:/ 

[xn--nding-jua]

Cool. Would be great to have a bootmenu to select between OpenX32 and the original Firmware. Should be possible to create a fifth Partition on a larger SD Card. Or we could place our barebox at 0x400 of the SD Card and move the DCP Loader to a later position.

Your progress looks promising 👍

[schulz-alexander]

First boot from sd card worked!

The trick was to use just allowed ranges in the DCD-Table, as mentioned in the reference manual ;-)
Setting the GPIO-PINs was not allowed.

[schulz-alexander]