What is UNIT-V Linux?
From https://docs.m5stack.com/#/en/unit/unitv
Introduction
I ran ** Linux ** on ** UNIT-V ** of size ** 4x2.5cm **.
M5Stack's UNIT-V (AI Camera) is small and nice (4g, 4x2.5x1.5cm). The memory is 8MB (by the way, ESP32 is 520KB, Raspberry Pi Zero W is 512MB). ** There is no LAN or WiFi. ** External connections are USB and ** 2 GPIOs ** only (UART or I 2 </ sup> C).
Linux and Tiny C Compiler seem to be in beta. Made by Shenzhen Sipeed Technology.
The UNIT-V SoC chip is the featured ** K210 **. Dual core 64 bit ** RISC-V ** CPU with ** Neural Network Processor **.
From https://kendryte.com/
UNIT-V comparison table
| UNIT-V | M5StickC | Raspberry Pi Zero W | Adafruit Feather nRF52840 Express | |
|---|---|---|---|---|
| concept | RISC-V-equipped AI chip | Batteries, screens and cases | General purpose Linux | Battery powered |
| SoC chip/Company | K210 /Kendryte |
ESP32 /Espressif Systems |
BCM2835 /Broadcom |
nRF52840 /Nordic |
| CPU | RISC-V | Xtensa LX6/Tensilica | ARM11 | ARM Cortex-M4 |
| CPU(Number of cores/bit) | 2/64 | 2/32 | 1/32 | 1/32 |
| clock(Mhz) | 400 | 240 | 1000 | 64 |
| memory(MB) | 8 | 520KB | 512 | 256KB |
| Flash(MB) | 16 | 4 | None | 1 |
| storage | Micro SD | None | microSD | None |
| WiFi/BT | None | ○ | ○ | ○ |
| USB | ○ | ○ | ○ | ○ |
| IF(The number of pins) | GROVE4pin | GROVE4pin, Extended 8pin |
GPIO 40pin | GPIO 21pin |
| Language / OS | MicroPython | MicroPython, Arduino | Raspbian | MicroPython, Arduino |
| Current(mA) | ？ | 100? | 150 | 25 |
| weight(g) | 4 | 15.1 | 9 | 6 |
| Remarks | Neural Network Processor(KPU) 0.8Tops, Camera、 RGB LED | 80 mAh Lipo, LCD(0.96),gyro, LED | HDMI | NFC, IEEE 802.15.4 |
Compile and execute C language (on UNIT-V)
/usr/local # uname -a
Linux k210 5.6.0-rc1-g9dbcd412b #16 SMP Sun Feb 16 01:45:41 CST 2020 riscv64 GNU/Linux
/usr/local # cat main.c
int _start()
{
for(int i = 0; i < 3; i++) {
printf("%d hello\n", i);
}
return 0;
}
/usr/local # tcc -run -nostdlib main.c
main.c:4: warning: implicit declaration of function 'printf'
0 hello
1 hello
2 hello
/usr/local #
Tiny C Compiler boot options
/usr/local # tcc -v
tcc version 0.9.27 ( Linux)
/usr/local # tcc
Tiny C Compiler 0.9.27 - Copyright (C) 2001-2006 Fabrice Bellard
Usage: tcc [options...] [-o outfile] [-c] infile(s)...
tcc [options...] -run infile [arguments...]
General options:
-c compile only - generate an object file
-o outfile set output filename
-run run compiled source
-fflag set or reset (with 'no-' prefix) 'flag' (see tcc -hh)
-std=c99 Conform to the ISO 1999 C standard (default).
-std=c11 Conform to the ISO 2011 C standard.
-Wwarning set or reset (with 'no-' prefix) 'warning' (see tcc -hh)
-w disable all warnings
-v -vv show version, show search paths or loaded files
-h -hh show this, show more help
-bench show compilation statistics
- use stdin pipe as infile
@listfile read arguments from listfile
Preprocessor options:
-Idir add include path 'dir'
-Dsym[=val] define 'sym' with value 'val'
-Usym undefine 'sym'
-E preprocess only
Linker options:
-Ldir add library path 'dir'
-llib link with dynamic or static library 'lib'
-r generate (relocatable) object file
-shared generate a shared library/dll
-rdynamic export all global symbols to dynamic linker
-soname set name for shared library to be used at runtime
-Wl,-opt[=val] set linker option (see tcc -hh)
Debugger options:
-g generate runtime debug info
-bt[N] link with backtrace (stack dump) support [show max N callers]
Misc. options:
-x[c|a|b|n] specify type of the next infile (C,ASM,BIN,NONE)
-nostdinc do not use standard system include paths
-nostdlib do not link with standard crt and libraries
-Bdir set tcc's private include/library dir
-MD generate dependency file for make
-MF file specify dependency file name
-m32/64 defer to i386/x86_64 cross compiler
Tools:
create library : tcc -ar [rcsv] lib.a files
/usr/local #
Linux boot message
[ 0.000000] Linux version 5.6.0-rc1-g9dbcd412b (vowstar@ryzen) (gcc version 9.2.0 (Buildroot 2020.02-git-g2ceb6f4a3f)) #16 SMP Sun Feb 16 01:45:41 CST 2020
[ 0.000000] earlycon: sifive0 at MMIO 0x0000000038000000 (options '')
[ 0.000000] printk: bootconsole [sifive0] enabled
[ 0.000000] initrd not found or empty - disabling initrd
[ 0.000000] Zone ranges:
[ 0.000000] DMA32 [mem 0x0000000080000000-0x00000000807fffff]
[ 0.000000] Normal empty
[ 0.000000] Movable zone start for each node
[ 0.000000] Early memory node ranges
[ 0.000000] node 0: [mem 0x0000000080000000-0x00000000807fffff]
[ 0.000000] Initmem setup node 0 [mem 0x0000000080000000-0x00000000807fffff]
[ 0.000000] elf_hwcap is 0x112d
[ 0.000000] percpu: max_distance=0x18000 too large for vmalloc space 0x0
[ 0.000000] percpu: Embedded 12 pages/cpu s18272 r0 d30880 u49152
[ 0.000000] Built 1 zonelists, mobility grouping off. Total pages: 2020
[ 0.000000] Kernel command line: earlycon console=ttySIF0
[ 0.000000] Dentry cache hash table entries: 1024 (order: 1, 8192 bytes, linear)
[ 0.000000] Inode-cache hash table entries: 512 (order: 0, 4096 bytes, linear)
[ 0.000000] Sorting __ex_table...
[ 0.000000] mem auto-init: stack:off, heap alloc:off, heap free:off
[ 0.000000] Memory: 4936K/8192K available (918K kernel code, 110K rwdata, 166K rodata, 1717K init, 91K bss, 3256K reserved, 0K cma-reserved)
[ 0.000000] rcu: Hierarchical RCU implementation.
[ 0.000000] rcu: RCU calculated value of scheduler-enlistment delay is 25 jiffies.
[ 0.000000] NR_IRQS: 0, nr_irqs: 0, preallocated irqs: 0
[ 0.000000] plic: mapped 65 interrupts with 2 handlers for 4 contexts.
[ 0.000000] riscv_timer_init_dt: Registering clocksource cpuid [0] hartid [0]
[ 0.000000] clocksource: riscv_clocksource: mask: 0xffffffffffffffff max_cycles: 0x3990be68b, max_idle_ns: 881590404272 ns
[ 0.000014] sched_clock: 64 bits at 7MHz, resolution 128ns, wraps every 4398046511054ns
[ 0.008238] Console: colour dummy device 80x25
[ 0.012472] Calibrating delay loop (skipped), value calculated using timer frequency.. 15.60 BogoMIPS (lpj=31200)
[ 0.022677] pid_max: default: 4096 minimum: 301
[ 0.027290] Mount-cache hash table entries: 512 (order: 0, 4096 bytes, linear)
[ 0.034415] Mountpoint-cache hash table entries: 512 (order: 0, 4096 bytes, linear)
[ 0.044822] rcu: Hierarchical SRCU implementation.
[ 0.049619] smp: Bringing up secondary CPUs ...
[ 0.054772] smp: Brought up 1 node, 2 CPUs
[ 0.059152] devtmpfs: initialized
[ 0.065758] clocksource: jiffies: mask: 0xffffffff max_cycles: 0xffffffff, max_idle_ns: 7645041785100000 ns
[ 0.074778] futex hash table entries: 16 (order: -2, 1024 bytes, linear)
[ 0.082792] Kendryte K210 SoC sysctl
[ 0.096502] clocksource: Switched to clocksource riscv_clocksource
[ 0.213963] workingset: timestamp_bits=62 max_order=11 bucket_order=0
[ 0.221326] 38000000.serial: ttySIF0 at MMIO 0x38000000 (irq = 1, base_baud = 0) is a SiFive UART v0
[ 0.229801] printk: console [ttySIF0] enabled
[ 0.229801] printk: console [ttySIF0] enabled
[ 0.238411] printk: bootconsole [sifive0] disabled
[ 0.238411] printk: bootconsole [sifive0] disabled
[ 0.250662] random: get_random_bytes called from 0x00000000801b2128 with crng_init=0
[ 0.259387] devtmpfs: mounted
[ 0.266032] Freeing unused kernel memory: 1716K
[ 0.269822] This architecture does not have kernel memory protection.
[ 0.276234] Run /sbin/init as init process
[ 0.280428] Run /etc/init as init process
[ 0.284708] Run /bin/init as init process
--------------------------------------
| Kendryte K210 Linux mod by vowstar |
--------------------------------------
Mounting /proc
Starting shell
BusyBox v1.32.0.git (2020-02-15 12:47:51 CST) hush - the humble shell
Enter 'help' for a list of built-in commands.
/ # help
Built-in commands:
------------------
. Run commands in file
bg Resume job in background
break Exit loop
cd Change directory
continue Start new loop iteration
eval Construct and run shell command
exec Execute command, don't return to shell
export Set environment variables
fg Bring job to foreground
history Show history
jobs List jobs
kill Send signals to processes
local Set local variables
read Input into variable
readonly Make variables read-only
return Return from function
set Set positional parameters
shift Shift positional parameters
trap Trap signals
type Show command type
ulimit Control resource limits
umask Set file creation mask
unset Unset variables
wait Wait for process to finish
/ #
Linux environment
The result of cat / proc / cpuinfo is a dual core 64 bit ** RISC-V ** CPU.
/ # uname -a
Linux k210 5.6.0-rc1-g9dbcd412b #16 SMP Sun Feb 16 01:45:41 CST 2020 riscv64 GNU/Linux
/ # cat /proc/cpuinfo
processor.: 0
hart..: 0
isa..: rv64imafdc
processor.: 1
hart..: 1
isa..: rv64imafdc
/ # env
HOME=/
TERM=linux
PWD=/
HUSH_VERSION=1.32.0.git
/ # ps -l
S UID PID PPID VSZ RSS TTY STIME TIME CMD
S 0 1 0 480 0 0:0 23:59 00:00:00 /bin/sh
S 0 2 0 0 0 0:0 23:59 00:00:00 [kthreadd]
I 0 3 2 0 0 0:0 23:59 00:00:00 [rcu_gp]
I 0 4 2 0 0 0:0 23:59 00:00:00 [rcu_par_gp]
I 0 5 2 0 0 0:0 23:59 00:00:00 [kworker/0:0-eve]
I 0 6 2 0 0 0:0 23:59 00:00:00 [kworker/0:0H]
I 0 7 2 0 0 0:0 23:59 00:00:00 [kworker/u4:0-ev]
I 0 8 2 0 0 0:0 23:59 00:00:00 [mm_percpu_wq]
S 0 9 2 0 0 0:0 23:59 00:00:00 [ksoftirqd/0]
I 0 10 2 0 0 0:0 23:59 00:00:00 [rcu_sched]
S 0 11 2 0 0 0:0 23:59 00:00:00 [migration/0]
S 0 12 2 0 0 0:0 23:59 00:00:00 [cpuhp/0]
S 0 13 2 0 0 0:0 23:59 00:00:00 [cpuhp/1]
S 0 14 2 0 0 0:0 23:59 00:00:00 [migration/1]
S 0 15 2 0 0 0:0 23:59 00:00:00 [ksoftirqd/1]
I 0 16 2 0 0 0:0 23:59 00:00:00 [kworker/1:0-eve]
I 0 17 2 0 0 0:0 23:59 00:00:00 [kworker/1:0H]
S 0 18 2 0 0 0:0 23:59 00:00:00 [kdevtmpfs]
I 0 19 2 0 0 0:0 23:59 00:00:00 [writeback]
I 0 20 2 0 0 0:0 23:59 00:00:00 [kworker/0:1-eve]
S 0 21 2 0 0 0:0 23:59 00:00:00 [kswapd0]
I 0 22 2 0 0 0:0 23:59 00:00:00 [kworker/1:1-mm_]
I 0 24 2 0 0 0:0 00:00 00:00:00 [kworker/u4:1]
R 0 38 1 316 0 0:0 00:03 00:00:00 ps -l
/ # ps -e
ps: invalid option -- e
ls / etc is empty.
# ls /
bin dev etc proc root sbin sys tmp usr
/ # ls /bin
arch chown grep ls printenv setserial umount
bash cp hush mkdir ps sh uname
busybox date init mknod pwd sleep usleep
cat dmesg kill more rm stty vi
chgrp echo link mount rmdir touch
chmod false ln mv sed true
/ # ls /dev
console tty20 tty4 tty59
cpu_dma_latency tty21 tty40 tty6
full tty22 tty41 tty60
kmsg tty23 tty42 tty61
null tty24 tty43 tty62
ptmx tty25 tty44 tty63
random tty26 tty45 tty7
tty tty27 tty46 tty8
tty0 tty28 tty47 tty9
tty1 tty29 tty48 ttySIF0
tty10 tty3 tty49 urandom
tty11 tty30 tty5 vcs
tty12 tty31 tty50 vcs1
tty13 tty32 tty51 vcsa
tty14 tty33 tty52 vcsa1
tty15 tty34 tty53 vcsu
tty16 tty35 tty54 vcsu1
tty17 tty36 tty55 zero
tty18 tty37 tty56
tty19 tty38 tty57
tty2 tty39 tty58
/ # ls /etc
/ # ls /proc
1 20 buddyinfo iomem softirqs
10 21 bus ioports stat
11 23 cmdline irq sys
12 24 consoles kmsg thread-self
13 3 cpuinfo loadavg timer_list
14 31 device-tree locks tty
15 4 devices maps uptime
16 5 driver meminfo version
17 6 execdomains misc vmstat
18 7 filesystems mounts zoneinfo
19 8 fs pagetypeinfo
2 9 interrupts self
/ # ls /root
/ # ls /sbin
runlevel
/ # ls /sys
/ # ls /tmp
/ # ls /usr
bin include lib sbin
/ # ls /usr/bin
[ env id seq tty wall
[[ expr last tail uniq wc
awk find printf tcc unlink who
basename head readlink tee users yes
dirname hostid realpath test w
/ # ls /usr/include
libtcc.h
/ # ls /usr/lib
crt1.o libtcc.a tcc
/ # ls /usr/sbin
chroot readahead
/ #
There is no df command.
/ # who
/ # df
sh: can't execute 'df': No such file or directory
/ # tty
/dev/console
/ #
Reference material
Try Maix Linux image with Tiny C Compiler: https://twitter.com/SipeedIO/status/1228881079236362240
MAIX/MaixLinux/Firmware http://dl.sipeed.com/MAIX/MaixLinux/Firmware Maix-linux-5.6-rc1_tcc.bin 3.1 MB Maix-linux-5.6-rc1_preview0.1.bin 1.7 MB
sipeed/kflash.py https://github.com/sipeed/kflash.py
Micom shop in Torinaki-ri (71) Kendryte K210, AI chip with RISC-V https://jhalfmoon.com/dbc/2019/10/23/鳥なき里のマイコン屋71-kendryte-k210、risc-v搭載aiチップ/
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