Apache NuttX RTOS for Pine64 Star64 64-bit RISC-V SBC (StarFive JH7110)

Read the articles...

• "64-bit RISC-V with Apache NuttX Real-Time Operating System"

• "Rolling to RISC-V"

Linux Images for Star64

Let's examine the Linux Images for Star64 SBC, to see how U-Boot Bootloader is configured. (We'll boot NuttX later with U-Boot)

According to Software Releases for Star64, we have...

• Yocto Images at pine64.my-ho.st

  Let's inspect star64-image-minimal

• Armbian Images

  Let's inspect Armbian 23.8 Lunar (Minimal)

Armbian Image for Star64

Let's inspect the Armbian Image for Star64: Armbian 23.8 Lunar (Minimal)

Uncompress the .xz, mount the .img file on Linux / macOS / Windows as an ISO Volume.

The image contains 1 used partition: armbi_root (642 MB) that contains the Linux Root Filesystem.

We see the U-Boot Bootloader Configuration at armbi_root/boot/uEnv.txt...

fdt_high=0xffffffffffffffff
initrd_high=0xffffffffffffffff

kernel_addr_r=0x44000000
kernel_comp_addr_r=0x90000000
kernel_comp_size=0x10000000

fdt_addr_r=0x48000000
ramdisk_addr_r=0x48100000

# Move distro to first boot to speed up booting
boot_targets=distro mmc1 dhcp 

distro_bootpart=1

# Fix missing bootcmd
bootcmd=run bootcmd_distro

Yocto Image for Star64

Let's inspect the Yocto Image for Star64: star64-image-minimal

Uncompress the .bz2, rename as .img. Balena Etcher won't work with .bz2 files!

Write the .img to a microSD Card with Balena Etcher. Insert the microSD Card into a Linux Machine. (Like Pinebook Pro)

We'll see 4 used partitions...

• spl (2 MB): ???

• uboot (4 MB): U-Boot Bootloader

• boot (380 MB): Boot Configuration for U-Boot

• root (686 MB): Linux Root Filesystem

Plus 2 unused partitions. (Why?)

boot partition has 2 files...

$ ls -l /run/media/luppy/boot
total 14808
-rw-r--r-- 1 luppy luppy 15151064 Apr  6  2011 fitImage
-rw-r--r-- 1 luppy luppy     1562 Apr  6  2011 vf2_uEnv.txt

boot/vf2_uEnv.txt contains the U-Boot Bootloader Configuration...

# This is the sample jh7110_uEnv.txt file for starfive visionfive U-boot
# The current convention (SUBJECT TO CHANGE) is that this file
# will be loaded from the third partition on the
# MMC card.
#devnum=1
partnum=3

# The FIT file to boot from
fitfile=fitImage

# for debugging boot
bootargs_ext=if test ${devnum} = 0; then setenv bootargs "earlyprintk console=tty1 console=ttyS0,115200 rootwait earlycon=sbi root=/dev/mmcblk0p4"; else setenv bootargs "earlyprintk console=tty1 console=ttyS0,115200 rootwait earlycon=sbi root=/dev/mmcblk1p4"; fi;
#bootargs=earlyprintk console=ttyS0,115200 debug rootwait earlycon=sbi root=/dev/mmcblk1p4

# for addr info
fileaddr=0xa0000000
fdtaddr=0x46000000
# boot Linux flat or compressed 'Image' stored at 'kernel_addr_r'
kernel_addr_r=0x40200000
irdaddr=46100000
irdsize=5f00000

# Use the FDT in the FIT image..
setupfdt1=fdt addr ${fdtaddr}; fdt resize;

setupird=setexpr irdend ${irdaddr} + ${irdsize}; fdt set /chosen linux,initrd-start <0x0 0x${irdaddr}>; fdt set /chosen linux,initrd-end <0x0 0x${irdend}>

setupfdt2=fdt set /chosen bootargs "${bootargs}";

bootwait=setenv _delay ${bootdelay}; echo ${_delay}; while test ${_delay} > 0; do sleep 1; setexpr _delay ${_delay} - 1; echo ${_delay}; done

boot2=run bootargs_ext; mmc dev ${devnum}; fatload mmc ${devnum}:${partnum} ${fileaddr} ${fitfile}; bootm start ${fileaddr}; run setupfdt1;run setupird;run setupfdt2; bootm loados ${fileaddr}; run chipa_set_linux; run cpu_vol_set; echo "Booting kernel in"; booti ${kernel_addr_r} ${irdaddr}:${filesize} ${fdtaddr}

TODO: Yocto boots from FIT File fitImage? Is this a Linux Flat Image?

TODO