I tried:
git clone git://git.buildroot.net/buildroot
cd buildroot
git checkout 2019.08
make qemu_aarch64_virt_defconfig
make menuconfig
In menuconfig, I set:
Bootloaders
U-Boot configuration (Using an in-tree board defconfig file)
qemu_arm64
Kernel
Install kernel image to /boot in target
and finally:
make BR2_JLEVEL="$nproc"
Now, I can boot fine without U-Boot with the command line mentioned at: How to download the Torvalds Linux Kernel master, (re)compile it, and boot it with QEMU?
./output/host/usr/bin/qemu-system-aarch64 -M virt -cpu cortex-a57 -nographic -smp 1 -kernel output/images/Image -append "root=/dev/vda console=ttyAMA0" -netdev user,id=eth0 -device virtio-net-device,netdev=eth0 -drive file=output/images/rootfs.ext4,if=none,format=raw,id=hd0 -device virtio-blk-device,drive=hd0
but that is not using U-Boot.
When I do:
ls -l output/images/
it contains:
-rw-r--r-- 1 ciro ciro 6.5M 2019-09-20_13:36:23 Image
-rw-r--r-- 1 ciro ciro 60M 2019-09-20_13:39:02 rootfs.ext2
lrwxrwxrwx 1 ciro ciro 11 2019-09-20_13:36:25 rootfs.ext4 -> rootfs.ext2
-rw-r--r-- 1 ciro ciro 583K 2019-09-20_13:34:15 u-boot.bin
so there is a U-Boot binary there: u-boot.bin, but how do I use that with QEMU?
I tried as mentioned at: Can ARM qemu system emulator boot from card image without kernel param? to remove -kernel and -append and add -bios u-boot.bin:
./output/host/usr/bin/qemu-system-aarch64 -M virt -cpu cortex-a57 -nographic -smp 1 -bios output/images/u-boot.bin -netdev user,id=eth0 -device virtio-net-device,netdev=eth0 -drive file=output/images/rootfs.ext4,if=none,format=raw,id=hd0 -device virtio-blk-device,drive=hd0
Now I do get the U-Boot shell, but boot fails and leaves me no the U-Boot prompt:
U-Boot 2019.07 (Sep 20 2019 - 13:34:10 +0100)
DRAM: 128 MiB
Flash: 128 MiB
*** Warning - bad CRC, using default environment
In: pl011#9000000
Out: pl011#9000000
Err: pl011#9000000
Net:
Warning: virtio-net#31 using MAC address from ROM
eth0: virtio-net#31
Hit any key to stop autoboot: 0
starting USB...
No working controllers found
USB is stopped. Please issue 'usb start' first.
scanning bus for devices...
Device 0: unknown device
Device 0: QEMU VirtIO Block Device
Type: Hard Disk
Capacity: 60.0 MB = 0.0 GB (122880 x 512)
... is now current device
** No partition table - virtio 0 **
starting USB...
No working controllers found
BOOTP broadcast 1
DHCP client bound to address 10.0.2.15 (2 ms)
Using virtio-net#31 device
TFTP from server 10.0.2.2; our IP address is 10.0.2.15
Filename 'boot.scr.uimg'.
Load address: 0x40200000
Loading: *
TFTP error: 'Access violation' (2)
Not retrying...
BOOTP broadcast 1
DHCP client bound to address 10.0.2.15 (0 ms)
Using virtio-net#31 device
TFTP from server 10.0.2.2; our IP address is 10.0.2.15
Filename 'boot.scr.uimg'.
Load address: 0x40400000
Loading: *
TFTP error: 'Access violation' (2)
Not retrying...
=>
so it appears that U-Boot cannot handle the VirtIO device? Or according to Peter, I have to create a partition table. I couldn't find that automatically in Buildroot, but I could do it manually, here is one approach: https://unix.stackexchange.com/questions/209566/how-to-format-a-partition-inside-of-an-img-file/527132#527132
Another approach would be to keep -kernel -append and let QEMU put the kernel into memory as done without U-Boot, and then use the booti U-Boot command I've found on help:
booti - boot Linux kernel 'Image' format from memory
so I just need to find out its address. But that is kind of cheating since I want U-boot to do the hard work rather than cheat with QEMU.
My goal is to reach a good setup to develop U-Boot and QEMU's early boot stuff.
Given that u-boot correctly detects the virtio block device, I think it is unlikely that it cannot handle it. The error printed is "** No partition table - virtio 0 **", which is correct, because you've set up the block device to contain just rootfs.ext4, which will be a filesystem image. That suggests that you'll have more luck if you create a disk image with a partition table and write the rootfs to a partition within the disk image.
I followed Peter's advice and put it into a partitioned image with the sfdisk-fs-to-img command from https://unix.stackexchange.com/questions/209566/how-to-format-a-partition-inside-of-an-img-file/527132#527132
I am now able to read the root filesystem with:
ls virtio 0 /boot
and that contains Image file.
Now I think there are only some U-Boot specifics to resolve, which I'm not very familiar with:
load /boot/Image into memory with something like load virtio 0 0x100000 /boot/Image. TODO which address is valid? This arbitrary choice gave ** Reading file would overwrite reserved memory **
find out how to load the DTB and kernel CLI arguments. The DTB would need to be auto-generated with QEMU with qemu-system-aarch64 -machine dumpdtb=dtb.dtb
boot it with something like: booti 0x100000
I was hoping Buildroot would have automated things a bit more for me sadface.
I have an embedded Linux system that uses ramdisk boot so it has run time no persistent storage available (it does have Flash to store kernel and ramdisk).
The only connectivity is RS-232 serial login console. So I am limited by what is provided by its built in busybox. I want to retrieve the ramdisk, modify it, and rewrite the ramdisk. The kernel does not have Flash filesystem support built-in. The ramdisk partition size is about 10 MBytes. When all files in the user directory are deleted, the free ramdisk size is about 14 MBytes.
The command dd is available so I can copy the ramdisk partition to the ramdisk, and can write to the flash from a ramdisk file. flashcp is also available.
So my problem is now how to receive and send binary files through the RS-232 serial console?
I research the followings and none is useful for me:
Linux command to send binary file to serial port with HW flow control? on stackoverflow
Binary data over serial terminal on stackoverflow
Transferring files using serial console on k.japko.eu
File transfer over a serial line on superuser.com
How to get file to a host when all you have is a serial console? on stackexchange
Mostly because x/y/zmodem are not available in the busybox.
Any idea? Thanks!
Per the request, here's what I should have included in the first place.
Available u-boot commands:
U-Boot >?
? - alias for 'help'
askenv - get environment variables from stdin
base - print or set address offset
bdinfo - print Board Info structure
boot - boot default, i.e., run 'bootcmd'
bootd - boot default, i.e., run 'bootcmd'
bootm - boot application image from memory
cmp - memory compare
coninfo - print console devices and information
cp - memory copy
crc32 - checksum calculation
crc32_chk_uimage- checksum calculation of an image for u-boot
echo - echo args to console
editenv - edit environment variable
env - environment handling commands
exit - exit script
false - do nothing, unsuccessfully
fatinfo - print information about filesystem
fatload - load binary file from a dos filesystem
fatls - list files in a directory (default /)
fatwrite- write file into a dos filesystem
go - start application at address 'addr'
gpio - input/set/clear/toggle gpio pins
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
loady - load binary file over serial line (ymodem mode)
loop - infinite loop on address range
md - memory display
mdc - memory display cyclic
mm - memory modify (auto-incrementing address)
mw - memory write (fill)
mwc - memory write cyclic
nm - memory modify (constant address)
printenv- print environment variables
reset - Perform RESET of the CPU
run - run commands in an environment variable
saveenv - save environment variables to persistent storage
saves - save S-Record file over serial line
setenv - set environment variables
sf - SPI flash sub-system
showvar - print local hushshell variables
sleep - delay execution for some time
source - run script from memory
sspi - SPI utility command
test - minimal test like /bin/sh
true - do nothing, successfully
usb - USB sub-system
usbboot - boot from USB device
version - print monitor, compiler and linker version
U-Boot >
Available busybox commands:
BusyBox v1.13.2 (2015-03-16 10:50:56 EDT) multi-call binary
Copyright (C) 1998-2008 Erik Andersen, Rob Landley, Denys Vlasenko
and others. Licensed under GPLv2.
See source distribution for full notice.
Usage: busybox [function] [arguments]...
or: function [arguments]...
BusyBox is a multi-call binary that combines many common Unix
utilities into a single executable. Most people will create a
link to busybox for each function they wish to use and BusyBox
will act like whatever it was invoked as!
Currently defined functions:
[, [[, addgroup, adduser, ar, ash, awk, basename, blkid,
bunzip2, bzcat, cat, chattr, chgrp, chmod, chown, chpasswd,
chroot, chvt, clear, cmp, cp, cpio, cryptpw, cut, date,
dc, dd, deallocvt, delgroup, deluser, df, dhcprelay, diff,
dirname, dmesg, du, dumpkmap, dumpleases, echo, egrep, env,
expr, false, fbset, fbsplash, fdisk, fgrep, find, free,
freeramdisk, fsck, fsck.minix, fuser, getopt, getty, grep,
gunzip, gzip, halt, head, hexdump, hostname, httpd, hwclock,
id, ifconfig, ifdown, ifup, inetd, init, insmod, ip, kill,
killall, klogd, last, less, linuxrc, ln, loadfont, loadkmap,
logger, login, logname, logread, losetup, ls, lsmod, makedevs,
md5sum, mdev, microcom, mkdir, mkfifo, mkfs.minix, mknod,
mkswap, mktemp, modprobe, more, mount, mv, nc, netstat,
nice, nohup, nslookup, od, openvt, passwd, patch, pidof,
ping, ping6, pivot_root, poweroff, printf, ps, pwd, rdate,
rdev, readahead, readlink, readprofile, realpath, reboot,
renice, reset, rm, rmdir, rmmod, route, rtcwake, run-parts,
sed, seq, setconsole, setfont, sh, showkey, sleep, sort,
start-stop-daemon, strings, stty, su, sulogin, swapoff,
swapon, switch_root, sync, sysctl, syslogd, tail, tar, tcpsvd,
tee, telnet, telnetd, test, tftp, tftpd, time, top, touch,
tr, traceroute, true, tty, udhcpc, udhcpd, udpsvd, umount,
uname, uniq, unzip, uptime, usleep, vconfig, vi, vlock,
watch, wc, wget, which, who, whoami, xargs, yes, zcat
In uboot you could use loady/loadx to get file from pc via uart.I usually use teraterm to send file.
The process should be this:
run loady in uboot
use teraterm send data
the file is transfer to you device's memory located in 0x01000000.
Independently I found a way to upload binary files through the Linux console and I'll document the steps here in case others find it useful since I had a hard time looking for this information on the net.
Here's the theory: change the console mode to raw so all the binary traffic are't interpretted as console command, e.g. ctrl-C. Turn off echo so it doesn't add extra serial traffic. Run tar to accept input from the stdin. Since ctrl-C won't work, and tar won't know when to terminate, use a background task to kill the login shell so you can login again to do your staff.
Steps:
Create a script to run in the background. Change myvar variable so it kills the login shell after the transfer is complete. Currently 120 corresponds to 1200 seconds, sufficient for a 10 MBytes file. In addition edit the 808 to match your login shell PID:
create bg file:
myvar=120
while [ $myvar -gt 0 ]
do
myvar=$(( $myvar-1 ))
echo -e " $myvar \n"
ls -l
sleep 10
done
kill -9 808
Launch the script in the background:
in console type:
source ./bg &
Use stty to change console to raw mode and do not echo
in console type:
stty raw -echo
Start tar to untar stdin. Note: I have to use ctrl-J since no longer work after the stty command
in console type and ends with ctrl-j, not :
tar zx -f - 1> 1.log 2> 2.log
Start Teraterm to send binary file
Wait for completion and the new login prompt
I forgot I asked this question. I figured out how to make ssh connection which in turn allows many more things to be done more easily. Of course it requires sshd in addition to nc and stty so you are out of luck if these are not available on your embedded Linux. I have tried it several times and it seems to work well, allowing multiple ssh sessions to be established, and mc to transfer files.
You will need two shell sessions on the host computer, one to loop the serial port to socket, and the other for the ssh, and more if you want to establish more ssh sessions.
First you need to setup the serial port. The '--noreset' option for picocom does this:
sudo picocom --noreset -b 115200 -e b /dev/ttyUSB3
Quit picocom once this is done (^B^X to exit).
Next we need to verify that the line endings are not translated or else ssh won't work. In the first shell run:
cat /dev/ttyUSB3 | hexdump -C
In the second shell run:
echo "echo -e \"LFLF\\n\\nCRCR\\r\\rEND\"" > /dev/ttyUSB3
You may see that \n (0x0A) is translated to \r\n (0x0D0x0A)
Use stty to set raw mode without echo and you should see no more translation:
echo "stty raw -echo" > /dev/ttyUSB3
echo "echo -e \"LFLF\\n\\nCRCR\\r\\rEND\"" > /dev/ttyUSB3
Finally in the first shell run nc to funnel local traffic between the serial port and ssh socket:
cat /dev/ttyUSB3 | nc -l -p 2222 > /dev/ttyUSB3
and funnel remote serial traffic to sshd:
echo "while true ; do nc localhost 22 ; done" > /dev/ttyUSB3
and connect ssh with port forwarding:
ssh -vvv root#localhost -p 2222 -L 0.0.0.0:22022:localhost:22
you can make more ssh connections simultaneously:
ssh -vvv root#localhost -p 22022
if you use mc, you can connect to it so you can easily browse the remote file system and copy files:
sh://root#localhost:22022
Last words: nc strips the TCP headers so the ssh packets are no checksumed and are not retried. If there were data error, the connection will break. If you remember your login shell PID, you can kill it and login again, otherwise you have to reboot. The '-vvv' flag for the ssh is for debugging.