To do the bare metal stuff I want to do (and eventually do a diskless boot of my Kyu operating system) I need to fiddle with U-Boot. I have an SD card that is booting linux, so with a serial console hooked up, it is a simple matter (if you are quick) to type anything on the keyboard and have U-Boot drop to a command line. Interestingly the U-Boot prompt is "nanopi3#". U-Boot fiddling is all about changing environment variables, which are like so:
baudrate=115200
board_rev=05
bootargs=console=ttySAC0,115200n8 root=/dev/mmcblk0p2 rootfstype=ext4 rootwait init=/sbin/init loglevel=7 printk.time=1 consoleblank=0 lcd=HDMI720P60 bootdev=2
bootcmd=run mmcboot
bootdelay=1
bootpart=1
dtb_addr=0x49000000
dtb_name=s5p6818-nanopi3-rev05.dtb
dtb_reserve=if test -n "$dtb_addr"; then fdt addr $dtb_addr; fi
ethaddr=d2:a5:61:c9:2e:e4
fb_addr=0x46000000
fdt_high=0xffffffffffffffff
fdtcontroladdr=7daa2df0
firstboot=0
initrd_addr=0x48000000
initrd_high=0xffffffffffffffff
initrd_name=ramdisk.img
initrd_size=0x600000
kernel=Image
load_dtb=ext4load mmc ${rootdev}:${bootpart} ${dtb_addr} ${dtb_name}; run dtb_reserve
load_initrd=ext4load mmc ${rootdev}:${bootpart} ${initrd_addr} ${initrd_name}; setenv initrd_size 0x${filesize}
load_kernel=ext4load mmc ${rootdev}:${bootpart} ${loadaddr} ${kernel}
loadaddr=0x40080000
mmcboot=run load_kernel; run load_initrd; run load_dtb; booti ${loadaddr} ${initrd_addr}:${initrd_size} ${dtb_addr}
rootdev=1
rootpart=2
splashfile=logo.bmp
splashimage=0x47000000
splashpos=m,m
Environment size: 1113/16380 bytes
Page 15-5 on the user manual shows that DDR ram lives in a 2G region starting at 0x40000000
(of course we only have 1G), so ram is at 0x40000000 - 0x7fffffff.
So something like this ought to do (exactly the same as for the Orange Pi):
setenv bootaddr 0x40000000
setenv boot_kyu "echo Booting Kyu via dhcp ; dhcp ${bootaddr}; go ${bootaddr}"
setenv bootcmd "run boot_kyu"
saveenv
Doing this and then typing reset gives me the following error.
It looks like this U-boot was built without the dhcp command, which is unfortunate.
I type on the keyboard to get to the U-Boot prompt, and type help as advised.
It looks like there are no network related commands at all.
Maybe nobody even wrote a network driver for U-Boot for this chip.
That would create a lot of work for me.
Unknown command 'dhcp' - try 'help' nanopi3# help ? - alias for 'help' base - print or set address offset bdinfo - print Board Info structure bmp - manipulate BMP image data boot - boot default, i.e., run 'bootcmd' bootd - boot default, i.e., run 'bootcmd' bootelf - Boot from an ELF image in memory booti - boot arm64 Linux Image image from memory bootm - boot application image from memory bootvx - Boot vxWorks from an ELF image clrlogo - fill the boot logo area with black cmp - memory compare coninfo - print console devices and information cp - memory copy crc32 - checksum calculation dm - Driver model low level access echo - echo args to console editenv - edit environment variable env - environment handling commands exit - exit script ext4_img_write- Compressed ext4 image write. ext4load- load binary file from a Ext4 filesystem ext4ls - list files in a directory (default /) ext4size- determine a file's size ext4write- create a file in the root directory false - do nothing, unsuccessfully fastboot- use USB Fastboot protocol fatinfo - print information about filesystem fatload - load binary file from a dos filesystem fatls - list files in a directory (default /) fatsize - determine a file's size fatwrite- write file into a dos filesystem fdisk - mmc list or create ms-dos partition tables (MAX TABLE 7) fdt - flattened device tree utility commands go - start application at address 'addr' gpio - query and control gpio pins gpt - GUID Partition Table help - print command description/usage i2c - I2C sub-system iminfo - print header information for application image imxtract- extract a part of a multi-image itest - return true/false on integer compare loadb - load binary file over serial line (kermit mode) loads - load S-Record file over serial line loadx - load binary file over serial line (xmodem mode) loady - load binary file over serial line (ymodem mode) loop - infinite loop on address range md - memory display mm - memory modify (auto-incrementing address) mmc - MMC sub system mmcinfo - display MMC info mtest - simple RAM read/write test mw - memory write (fill) nm - memory modify (constant address) pmic - operations printenv- print environment variables regulator- uclass operations reset - Perform RESET of the CPU run - run commands in an environment variable saveenv - save environment variables to persistent storage sd_recovery- Image Update from SD Card setenv - set environment variables showvar - print local hushshell variables sleep - delay execution for some time source - run script from memory test - minimal test like /bin/sh true - do nothing, successfully udown - Download USB usb - USB sub-system usbboot - boot from USB device version - print monitor, compiler and linker version nanopi3# version U-Boot 2016.01-00025-gb5566ab172 (May 09 2018 - 13:52:47 +0800) aarch64-linux-gcc (ctng-1.23.0-150g-FA) 6.4.0 GNU ld (ctng-1.23.0-150g-FA) 2.28
Tom's electronics pages / tom@mmto.org