=熟悉《Linux设备驱动开发详解：基于最新的Linux4.0内核_宋宝华》的LINUX QEMU虚拟开发板
单板原型
基于的QEMU模拟的vexpress ARM Cortex-A9四核开发板
编译内核
Linux内核在/home/baohua/develop/linux目录中，在该目录下面，包含内核编译脚本：
export ARCH=arm
export CROSS_COMPILE=arm-linux-gnueabi-
make LDDD3_vexpress_defconfig
make zImage -j8
make modules -j8
make dtbs
cp arch/arm/boot/zImage extra/
cp arch/arm/boot/dts/*ca9.dtb extra/
cp .config extra/
由此可见，我们用的默认内核配置文件是LDDD3_vexpress_defconfig。
在源代码的根目录下会得到未压缩的内核映像vmlinux和内核符号表文件System.map， 在arch/arm/boot/目录下会得到压缩的内核映像zImage， 在内核各对应目录内得到选中的内核模块。
上述脚本也会自动将编译好的zImage和dtbs复制到extra目录中,即：
baohua@baohua-VirtualBox:~/develop$ find . -name zImage |xargs ls -al
-rwxrwxr-x 1 baohua baohua 3436008 2月 5 2020 ./linux/arch/arm/boot/zImage
-rwxrwxr-x 1 baohua baohua 3436008 2月 5 2020 ./linux/extra/zImage
baohua@baohua-VirtualBox:~/develop$ find . -name vexpress-v2p-ca9.dtb|xargs ls -al
-rw-rw-r-- 1 baohua baohua 14112 2月 5 2020 ./linux/arch/arm/boot/dts/vexpress-v2p-ca9.dtb
-rw-rw-r-- 1 baohua baohua 14112 2月 5 2020 ./linux/extra/vexpress-v2p-ca9.dtb
文件系统
extra目录下的vexpress.img是一张虚拟的SD卡，将作为根文件系统的存放介质。它能以loop的形式被挂载（mount）.
sudo mount -o loop,offset=$((2048*512)) extra/vexpress.img extra/img
编译内核模块
/home/baohua/develop/linux/module.sh编译模块的脚本，它会自动编译内核模块并安装到vexpress.img中，其内容如下：
make ARCH=arm CROSS_COMPILE=arm-linux-gnueabi- modules
sudo mount -o loop,offset=$((2048*512)) extra/vexpress.img extra/img
sudo make ARCH=arm modules_install INSTALL_MOD_PATH=extra/img
sudo umount extra/img
单板的启动
运行extra下面的 run-nolcd.sh :
cd /home/baohua/develop/linux/extra
./run-nolcd.sh
其内容如下,可以启动一个不含LCD的ARM Linux。run-nolcd.sh的内容为
qemu-system-arm -nographic -sd vexpress.img -M vexpress-a9 -m 512M -kernel zImage -dtb vexpress-v2p-ca9.dtb -smp 4 -append "init=/linuxrc root=/dev/mmcblk0p1 rw rootwait earlyprintk console=ttyAMA0" 2>/dev/null
qemu单板和vmware之间传递文件
单板的基本信息
# lsmod
Module Size Used by Not tainted
# cat cpuinfo
processor : 0
model name : ARMv7 Processor rev 0 (v7l)
BogoMIPS : 364.44
Features : half thumb fastmult vfp edsp neon vfpv3 tls vfpd32
CPU implementer : 0x41
CPU architecture: 7
CPU variant : 0x0
CPU part : 0xc09
CPU revision : 0
processor : 1
model name : ARMv7 Processor rev 0 (v7l)
BogoMIPS : 104.34
Features : half thumb fastmult vfp edsp neon vfpv3 tls vfpd32
CPU implementer : 0x41
CPU architecture: 7
CPU variant : 0x0
CPU part : 0xc09
CPU revision : 0
processor : 2
model name : ARMv7 Processor rev 0 (v7l)
BogoMIPS : 2.43
Features : half thumb fastmult vfp edsp neon vfpv3 tls vfpd32
CPU implementer : 0x41
CPU architecture: 7
CPU variant : 0x0
CPU part : 0xc09
CPU revision : 0
processor : 3
model name : ARMv7 Processor rev 0 (v7l)
BogoMIPS : 380.92
Features : half thumb fastmult vfp edsp neon vfpv3 tls vfpd32
CPU implementer : 0x41
CPU architecture: 7
CPU variant : 0x0
CPU part : 0xc09
CPU revision : 0
Hardware : ARM-Versatile Express
Revision : 0000
Serial : 0000000000000000
#
# cat meminfo
MemTotal: 513064 kB
MemFree: 502088 kB
MemAvailable: 499808 kB
Buffers: 64 kB
Cached: 1400 kB
SwapCached: 0 kB
Active: 1360 kB
Inactive: 204 kB
Active(anon): 100 kB
Inactive(anon): 0 kB
Active(file): 1260 kB
Inactive(file): 204 kB
Unevictable: 0 kB
Mlocked: 0 kB
SwapTotal: 0 kB
SwapFree: 0 kB
Dirty: 4 kB
Writeback: 0 kB
AnonPages: 100 kB
Mapped: 1032 kB
Shmem: 0 kB
Slab: 4548 kB
SReclaimable: 1132 kB
SUnreclaim: 3416 kB
KernelStack: 368 kB
PageTables: 28 kB
NFS_Unstable: 0 kB
Bounce: 0 kB
WritebackTmp: 0 kB
CommitLimit: 256532 kB
Committed_AS: 612 kB
VmallocTotal: 1548288 kB
VmallocUsed: 174728 kB
VmallocChunk: 1212448 kB
CmaTotal: 0 kB
CmaFree: 0 kB
# cat mounts
/dev/root / ext2 rw,relatime,errors=continue 0 0
devtmpfs /dev devtmpfs rw,relatime,size=256400k,nr_inodes=64100,mode=755 0 0
nodev /proc proc rw,relatime 0 0
nodev /sys sysfs rw,relatime 0 0
nodev /tmp tmpfs rw,relatime 0 0
nodev /sys/kernel/debug debugfs rw,relatime 0 0
nodev /dev/pts devpts rw,relatime,mode=600 0 0
# uname -a
Linux (none) 4.0.0-rc1+ #6 SMP Wed Feb 5 14:29:53 CST 2020 armv7l GNU/Linux
# cat /proc/cmdline
init=/linuxrc root=/dev/mmcblk0p1 rw rootwait earlyprintk console=ttyAMA0
# cd /proc
# cat interrupts
CPU0 CPU1 CPU2 CPU3
16: 73175 73036 73085 73107 GIC 29 twd
17: 9 0 0 0 GIC 34 timer
31: 0 0 0 0 GIC 47 eth0
34: 888 215 111 90 GIC 41 mmci-pl18x (cmd)
35: 5443 5690 5762 5512 GIC 42 mmci-pl18x (pio)
36: 8 0 0 0 GIC 44 kmi-pl050
37: 100 1 0 0 GIC 45 kmi-pl050
38: 1492 1930 115 57 GIC 37 uart-pl011
44: 0 0 0 0 GIC 36 rtc-pl031
IPI0: 0 1 1 1 CPU wakeup interrupts
IPI1: 0 0 0 0 Timer broadcast interrupts
IPI2: 288 255 283 324 Rescheduling interrupts
IPI3: 0 1 1 1 Function call interrupts
IPI4: 0 0 0 0 Single function call interrupts
IPI5: 0 0 0 0 CPU stop interrupts
IPI6: 0 0 0 0 IRQ work interrupts
IPI7: 0 0 0 0 completion interrupts
Err: 0
# cat devices
Character devices:
1 mem
2 pty
3 ttyp
4 /dev/vc/0
4 tty
5 /dev/tty
5 /dev/console
5 /dev/ptmx
7 vcs
10 misc
13 input
14 sound
29 fb
90 mtd
116 alsa
128 ptm
136 pts
180 usb
189 usb_device
204 ttyAMA
253 usbmon
254 rtc
Block devices:
259 blkext
8 sd
31 mtdblock
65 sd
66 sd
67 sd
68 sd
69 sd
70 sd
71 sd
128 sd
129 sd
130 sd
131 sd
132 sd
133 sd
134 sd
135 sd
179 mmc
254 virtblk
# df -h
Filesystem Size Used Available Use% Mounted on
/dev/root 45.5M 27.2M 16.0M 63% /
devtmpfs 250.4M 0 250.4M 0% /dev
nodev 250.5M 0 250.5M 0% /tmp
# fdisk -l
Disk /dev/mtdblock0: 134 MB, 134217728 bytes
255 heads, 63 sectors/track, 16 cylinders
Units = cylinders of 16065 * 512 = 8225280 bytes
Disk /dev/mtdblock0 doesn't contain a valid partition table
Disk /dev/mmcblk0: 50 MB, 50331648 bytes
31 heads, 24 sectors/track, 132 cylinders
Units = cylinders of 744 * 512 = 380928 bytes
Device Boot Start End Blocks Id System
/dev/mmcblk0p1 3 133 48128 83 Linux
Partition 1 has different physical/logical beginnings (non-Linux?):
phys=(0, 32, 33) logical=(2, 23, 9)
Partition 1 has different physical/logical endings:
phys=(6, 30, 24) logical=(132, 3, 24)
# lsblk
-/bin/sh: lsblk: not found
# iotop
-/bin/sh: iotop: not found
# ps
PID USER VSZ STAT COMMAND
1 root 1672 S init
2 root 0 SW [kthreadd]
3 root 0 SW [ksoftirqd/0]
5 root 0 SW< [kworker/0:0H]
6 root 0 SW [kworker/u8:0]
7 root 0 SW [rcu_sched]
8 root 0 SW [rcu_bh]
9 root 0 SW [migration/0]
10 root 0 SW [migration/1]
11 root 0 SW [ksoftirqd/1]
12 root 0 SW [kworker/1:0]
13 root 0 SW< [kworker/1:0H]
14 root 0 SW [migration/2]
15 root 0 SW [ksoftirqd/2]
16 root 0 SW [kworker/2:0]
17 root 0 SW< [kworker/2:0H]
18 root 0 SW [migration/3]
19 root 0 SW [ksoftirqd/3]
20 root 0 SW [kworker/3:0]
21 root 0 SW< [kworker/3:0H]
22 root 0 SW< [khelper]
23 root 0 SW [kdevtmpfs]
24 root 0 SW [kworker/u8:1]
26 root 0 SW< [perf]
47 root 0 SW [kworker/1:1]
279 root 0 SW [khungtaskd]
280 root 0 SW< [writeback]
282 root 0 SW< [kintegrityd]
283 root 0 SW< [bioset]
284 root 0 SW< [kblockd]
291 root 0 SW< [ata_sff]
409 root 0 SW< [rpciod]
424 root 0 SW [kswapd0]
425 root 0 SW [kworker/3:2]
472 root 0 SW [fsnotify_mark]
486 root 0 SW< [nfsiod]
511 root 0 SW [kworker/2:1]
593 root 0 SW [kworker/0:1]
599 root 0 SW< [kpsmoused]
601 root 0 SW [kworker/0:2]
663 root 0 SW [mmcqd/0]
682 root 0 SW< [deferwq]
713 root 1676 S -/bin/sh
721 root 1676 R ps
# busybox --help
BusyBox v1.18.5 (2014-12-01 10:44:09 CST) multi-call binary.
Copyright (C) 1998-2009 Erik Andersen, Rob Landley, Denys Vlasenko
and others. Licensed under GPLv2.
See source distribution for full notice.
Usage: busybox [function] [arguments]...
or: busybox --list[-full]
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:
[, [[, acpid, addgroup, adduser, adjtimex, ar, arp, arping, ash, awk,
base64, basename, beep, blkid, blockdev, bootchartd, brctl, bunzip2,
bzcat, bzip2, cal, cat, catv, chat, chattr, chgrp, chmod, chown,
chpasswd, chpst, chroot, chrt, chvt, cksum, clear, cmp, comm, cp, cpio,
crond, crontab, cryptpw, cttyhack, cut, date, dc, dd, deallocvt,
delgroup, deluser, depmod, devmem, df, dhcprelay, diff, dirname, dmesg,
dnsd, dnsdomainname, dos2unix, du, dumpkmap, dumpleases, echo, ed,
egrep, eject, env, envdir, envuidgid, ether-wake, expand, expr,
fakeidentd, false, fbset, fbsplash, fdflush, fdformat, fdisk,
fgconsole, fgrep, find, findfs, flock, fold, free, freeramdisk, fsck,
fsck.minix, fsync, ftpd, ftpget, ftpput, fuser, getopt, getty, grep,
gunzip, gzip, halt, hd, hdparm, head, hexdump, hostid, hostname, httpd,
hush, hwclock, id, ifconfig, ifdown, ifenslave, ifplugd, ifup, inetd,
init, insmod, install, ionice, iostat, ip, ipaddr, ipcalc, ipcrm, ipcs,
iplink, iproute, iprule, iptunnel, kbd_mode, kill, killall, killall5,
klogd, last, length, less, linux32, linux64, linuxrc, ln, loadfont,
loadkmap, logger, login, logname, logread, losetup, lpd, lpq, lpr, ls,
lsattr, lsmod, lspci, lsusb, lzcat, lzma, lzop, lzopcat, makedevs,
makemime, man, md5sum, mdev, mesg, microcom, mkdir, mkdosfs, mkfifo,
mkfs.minix, mkfs.vfat, mknod, mkpasswd, mkswap, mktemp, modinfo,
modprobe, more, mount, mountpoint, mpstat, msh, mt, mv, nameif,
nbd-client, nc, netstat, nice, nmeter, nohup, nslookup, ntpd, od,
openvt, passwd, patch, pgrep, pidof, ping, ping6, pipe_progress,
pivot_root, pkill, pmap, popmaildir, poweroff, powertop, printenv,
printf, ps, pscan, pwd, raidautorun, rdate, rdev, readahead, readlink,
readprofile, realpath, reboot, reformime, renice, reset, resize, rev,
rm, rmdir, rmmod, route, rtcwake, run-parts, runlevel, runsv, runsvdir,
rx, script, scriptreplay, sed, sendmail, seq, setarch, setconsole,
setfont, setkeycodes, setlogcons, setsid, setuidgid, sh, sha1sum,
sha256sum, sha512sum, showkey, slattach, sleep, smemcap, softlimit,
sort, split, start-stop-daemon, stat, strings, stty, su, sulogin, sum,
sv, svlogd, swapoff, swapon, switch_root, sync, sysctl, syslogd, tac,
tail, tar, tcpsvd, tee, telnet, telnetd, test, tftp, tftpd, time,
timeout, top, touch, tr, traceroute, traceroute6, true, tty, ttysize,
tunctl, udhcpc, udhcpd, udpsvd, umount, uname, uncompress, unexpand,
uniq, unix2dos, unlzma, unlzop, unxz, unzip, uptime, usleep, uudecode,
uuencode, vconfig, vi, vlock, volname, wall, watch, watchdog, wc, wget,
which, who, whoami, xargs, xz, xzcat, yes, zcat, zcip
# i2cdetect -l
-/bin/sh: i2cdetect: not found
# find /etc/init.d
/etc/init.d
/etc/init.d/rcS
# cat /etc/init.d/rcS
#!/bin/sh
mount -n -t proc nodev /proc
mount -n -t sysfs nodev /sys
mount -n -t tmpfs nodev /tmp
mount -n -t debugfs nodev /sys/kernel/debug
mkdir /dev/pts && mount -n -t devpts nodev /dev/pts
echo /sbin/mdev > /proc/sys/kernel/hotplug
mdev -s
cat /etc/motd
