ODROID-C1 was a $35 quad-core SBC from Hardkernel. ODROID-C1 support was introduced in NetBSD 7.0. It has been succeeded by the ODROID-C1+, which is supported by the same NetBSD kernel.
Supported hardware
- CPU: Cortex-A5: Amlogic S805 (4-core) at 1.5GHz
- CPU frequency scaling is supported with machdep.cpu sysctl tree
- SMP supported
- PL310 L2 cache controller
- GIC
- A5 global timer
- Watchdog timer
- "SDHC" and "SDIO" SD/MMC controllers (DMA)
- Serial console
- Framebuffer console
- USB host (OTG)
- Gigabit Ethernet (GMAC)
- RTL8211F PHY
- Hardware random number generator
- RTC
- GPIO
TODO
- USB device mode
- IR receiver
- I2C
- Audio
Installation (NetBSD 8.0 and later)
- Start with an ARMv7 image from evbarm-earmv7hf/binary/gzimg/ such as armv7.img, the latest is here.
- Build U-Boot for ODROID-C1 https://github.com/jaredmcneill/u-boot-odroid
- Write the bootloader to the empty space at the start of the base image:
# dd if=bl1.bin.hardkernel of=armv7.img bs=1 count=442 conv=notrunc # dd if=bl1.bin.hardkernel of=armv7.img bs=512 skip=1 seek=1 conv=notrunc # dd if=u-boot.bin.odroidc1 of=armv7.img bs=512 seek=64 conv=notrunc
Write the image to an SD card.
Tested 2021-02-19 with NetBSD-current, christos
- serial fights with ucb keyboard. (avoid by short circuiting cngetc in meson_uart.c to return -1)
- awge0 does not work reliably (can't even get a dhcp address, stops receiving packets after less than a minute)
- machine crashes under load
Installation (NetBSD 7.0/7.1)
- Start with an ARMv7 image from evbarm-earmv7hf/binary/gzimg/ such as armv7.img
- Build U-Boot for ODROID-C1 https://github.com/jaredmcneill/u-boot-odroid
- Pre-built binaries here: https://ftp.netbsd.org/pub/NetBSD/arch/evbarm/odroid-c1/u-boot-odroidc-v2011.03-20220520.tar.gz
- Note the location and size of the FFS partition in the armv7.img disklabel:
# $TOOLDIR/bin/nbdisklabel -M evbarm -B le armv7.img ... 8 partitions: # size offset fstype [fsize bsize cpg/sgs] a: 1359312 385024 4.2BSD 0 0 0 # (Cyl. 188 - 851*) b: 262144 122880 swap # (Cyl. 60 - 187) c: 1744336 0 unused 0 0 # (Cyl. 0 - 851*) d: 1744336 0 unused 0 0 # (Cyl. 0 - 851*) e: 114688 8192 MSDOS # (Cyl. 4 - 59)
- Write the bootloader to the empty space at the start of the base image:
# dd if=bl1.bin.hardkernel of=armv7.img bs=1 count=442 conv=notrunc # dd if=bl1.bin.hardkernel of=armv7.img bs=512 skip=1 seek=1 conv=notrunc # dd if=u-boot.bin of=armv7.img bs=512 seek=64 conv=notrunc
- Since the bootloader has overwritten the disklabel, we need to re-add partition "a" from the disklabel to the MBR partition table:
# $TOOLDIR/bin/armv7--netbsdelf-eabihf-fdisk -u armv7.img ... Which partition do you want to change?: [none] 1 The data for partition 1 is: sysid: [0..255 default: 169] start: [0..109cyl default: 63, 0cyl, 0MB] 385024 size: [0..85cyl default: 1359312, 85cyl, 664MB] 1359312 ... Which partition do you want to change?: [none] ... Should we write new partition table? [n] y
- Write the image to an SD card.
- Edit boot.ini on the MS-DOS partition. Note that the default boot.ini has
console=fbinbootargs, which you should remove if you want serial console:
ODROIDC-UBOOT-CONFIG
setenv bootargs "root=ld0f awge0.mac-address=${ethaddr} console=fb"
setenv bootcmd "fatload mmc 0:1 0x21000000 netbsd.ub; bootm 0x21000000"
run bootcmd
- On first boot, it will stop because of the wrong device in /etc/fstab. Take this opportunity to grow the root file-system:
# fdisk -u ld0
...
Which partition do you want to change?: [none] 1
The data for partition 1 is:
NetBSD (sysid 169)
start 385024, size 1359312 (664 MB, Cyls 23/246/32-108/147/55)
PBR is not bootable: All bytes are identical (0x00)
sysid: [0..255 default: 169]
start: [0..966cyl default: 385024, 24cyl, 188MB]
size: [0..942cyl default: 1359312, 85cyl, 664MB] $
...
Which partition do you want to change?: [none]
...
Should we write new partition table? [n] y
# resize_ffs -y /dev/rld0f
# reboot
- Next boot, create a new /etc/fstab:
# mount -u -o rw /dev/ld0f / # cat > /etc/fstab << EOF /dev/ld0f / ffs rw 1 1 /dev/ld0e /boot msdos rw 1 1 kernfs /kern kernfs rw ptyfs /dev/pts ptyfs rw procfs /proc procfs rw tmpfs /var/shm tmpfs rw,-m1777,-sram%25 EOF # reboot
HDMI
Framebuffer console
Simply add console=fb to the bootargs variable in boot.ini.
Video mode
HDMI video mode can be selected in U-Boot with the video command, e.g.:
odroidc#video dev open 1080P
To make this change permanent, add it to the bootcmd variable in boot.ini:
setenv bootcmd "video dev open 1080P; fatload mmc 0:1 0x21000000 netbsd.ub; bootm 0x21000000"
16 or 24 bpp?
ODROID-C1 defaults to 16bpp. If you want to try 24bpp, add fb.depth=24 to the kernel cmdline options in boot.ini. There are some issues with 24bpp mode and Xorg; see http://gnats.netbsd.org/49812.
Overscan compensation
If you have ODROID-C1 plugged into a TV, the edges of the screen may not be visible. You can scale down the framebuffer console with the hw.genfb0.scale sysctl, e.g.:
# sysctl -w hw.genfb0.scale=95
Setting scale to 100 disables scaling, any other value enables the scaler. Values between 10 and 100 are allowed.
To set this value at boot, you can add fb.scale=95 to the kernel cmdline options in boot.ini.
SYS_LED
The blue SYS_LED on the board is wired to GPIOAO_13. To control the LED from userland, set gpio=YES in rc.conf and add this to /etc/gpio.conf:
gpio4 13 set out sys_led
After rebooting, the LED state can be controlled with gpioctl(8).
# turn the light on gpioctl gpio4 sys_led on # turn the light off gpioctl gpio4 sys_led off # toggle the light state gpioctl gpio4 sys_led toggle
U-Boot Environment
To read/write U-Boot environment variables from NetBSD, download and compile the following program: http://ftp.netbsd.org/pub/NetBSD/misc/jmcneill/odroidc1/uenv.c
Automatically booting a backup kernel
These instructions assume the kernels live on eMMC. Adjust devices accordingly for SD card setup.
To setup an ODROID-C1 to fall back to a recovery kernel in the event of a boot failure, install the recovery kernel as /boot/onetbsd.ub.
Create /boot/boot.ini as follows:
ODROIDC-UBOOT-CONFIG
setenv bootargs "root=ld0f awge0.mac-address=${ethaddr}"
fatload mmc 0:1 0x22000000 boot.scr
source 0x22000000
Create /boot/boot.txt:
# regenerate with:
# mkubootimage -A arm -C none -O netbsd -T script -a 0 -n "NetBSD/odroidc1 boot" boot.txt boot.scr
setenv rescue_kernel "onetbsd.ub"
setenv kernel "netbsd.ub"
if test ${boot_rescue} = false; then
setenv boot_rescue true
saveenv
fatload mmc 0:1 0x21000000 ${kernel}
mw.l c1109900 0f08ffff # arm watchdog
bootm 0x21000000
else
fatload mmc 0:1 0x21000000 ${rescue_kernel}
bootm 0x21000000
fi
Generate boot.scr from boot.txt:
mkubootimage -A arm -C none -O netbsd -T script -a 0 -n "NetBSD/odroidc1 boot" /boot/boot.txt /boot/boot.scr
Install the uenv tool from above and add the following to root's crontab:
@reboot /usr/local/sbin/uenv ld0 boot_rescue false
Documentation
Amlogic S805 datasheet: http://dn.odroid.com/S805/Datasheet/S805_Datasheet%20V0.8%2020150126.pdf
ODROID-C1 UART pins
From ODROID Forum:
___UART____ |Pin 4 - GND| |Pin 3 - RXD| |Pin 2 - TXD| |Pin 1 - VCC| \___________| 3.3V LVTTL