I've been thinking some about how we create our disk images for aarch64
devices and how we'll eventually create images for riscv64 devices.
Currently we use u-boot to load extlinux to boot linux. I propose we use
u-boot with its EFI interface to load grub-efi to boot linux.

Major benefit of this is that we can create one generic aarch64 image
using raw-with-offset to create the image and then ship a separate
script to flash either the SD card or an SPI chip or whatever someone
wants. We also don't need to reflash u-boot at every reconfigure (I
couldn't follow the code well enough to see if that's currently the
case), just regenerate extlinux or grub-efi like we do on x86_64.

Currently here's the script to install u-boot on the disk image for a pine64:

(define install-allwinner64-u-boot
  #~(lambda (bootloader root-index image)
      (let ((spl (string-append bootloader "/libexec/u-boot-sunxi-with-spl.bin"))
            (u-boot (string-append bootloader "/libexec/u-boot-sunxi-with-spl.fit.itb")))
        (write-file-on-device spl (stat:size (stat spl))
                              image (* 8 1024))
        (write-file-on-device u-boot (stat:size (stat u-boot))
                              image (* 40 1024)))))

And in the OS config:

    (bootloader (bootloader-configuration
                 (bootloader u-boot-pine64-lts-bootloader)
                 (targets '("/dev/vda"))))

This would transition to (work in progress):

(define install-allwinner64-u-boot
  #~(lambda (bootloader root-index image)
      (let ((spl (string-append bootloader "/libexec/u-boot-sunxi-with-spl.bin"))
            (u-boot (string-append bootloader "/libexec/u-boot-sunxi-with-spl.fit.itb")))
        (write-file-on-device spl (stat:size (stat spl))
                              image (* 8 1024))
        (write-file-on-device u-boot (stat:size (stat u-boot))
                              image (* 40 1024)))))

;; This needs to be fixed up to actually work!!
;; To be run (as root): 'u-boot-installer-pine64-lts /dev/sda'
(define-public u-boot-installer-pine64-lts
  (program-file "u-boot-installer-pine64-lts"
    #~((let ((bootloader u-boot-pine64-lts)
             (image $1)))
       #$(install-allwinner-u-boot))))

(bootloader (bootloader-configuration
             (bootloader grub-efi)
             (targets '("/dev/vda"))))

(extra-special-file `(("/sbin/flash-u-boot" ,u-boot-installer-pine64-lts)))



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Efraim Flashner   <efraim@flashner.co.il>   אפרים פלשנר
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