测试使用busybox生成的根文件系统。测试内容较多，很杂。
1、修改"nfs-kernel-server"
1)、打开终端
输入"sudo vi /etc/default/nfs-kernel-server回车"，打开"nfs-kernel-server"文件。
输入密码"123456回车"
见下图：
2)、在最后面添加内容如下：
RPCNFSDOPTS="--nfs-version 2,3,4 --debug --syslog"
修改后，见下图：
3)、按"ESC键"，输入":wq回车"
输入"sudo /etc/init.d/nfs-kernel-server restart回车"，重启"nfs-kernel-server"
4)、在串口设置"bootargs"环境变量
连接串口通讯线，开启虚拟机，打开MobaXterm，给开饭上电，等待出现"Hit any key to stop autoboot"，按下"回车键"
先要保证开发板能从网络启动，然后才能测试"根文件系统"。
通过设置环境变量bootcmd的值，从网络启动linux系统
出现"STM32MP>"时输入setenv bootcmd 'tftp c2000000 uImage;tftp c4000000 stm32mp157d-atk.dtb;bootm c2000000 - c4000000'，设置从网络启动linux系统
出现"STM32MP>"时输入： saveenv，保存bootcmd的值
出现"STM32MP>"时输入： boot，启动 Linux 系统
输入"setenv bootargs 'console=ttySTM0,115200 root=/dev/nfs nfsroot=192.168.2.180:/home/zgq/linux/nfs/rootfs,proto=tcp rw ip=192.168.2.178:192.168.2.180:192.168.2.1:255.255.255.0::eth0:off'
回车"
输入"saveenv回车"
输入"boot回车"
解释：
"bootargs"环境变量
"console=ttySTM0,115200"表示串口波特率为115200
"192.168.2.180"为虚拟机IP地址
"/home/zgq/linux/nfs/rootfs"为根文件系统存放路径
"proto=tcp"表示使用TCP协议
"rw"表示nfs挂载的根文件系统可读可写
"192.168.2.178"为开发板IP地址
"192.168.2.1"为网关地址
"255.255.255.0"为子网掩码
"eth0"为设备名/网卡名
"off"不使用自动配置
举例：
setenv bootargs 'console=ttySTM0,115200 root=/dev/nfs nfsroot=192.168.2.180:/home/zgq/linux/nfs/rootfs,proto=tcp rw ip=192.168.2.178:192.168.2.180:192.168.2.1:255.255.255.0::eth0:off'
5)、串口输出结果：
Hit any key to stop autoboot: 0
STM32MP> setenv bootargs 'console=ttySTM0,115200 root=/dev/nfs nfsroot=192.168.2.180:/home/zgq/linux/nfs/rootfs,proto=tcp rw ip=192.168.2.178:192.168.2.180:192.168.2.1:255.255.255.0::eth0:off'
STM32MP> saveenv
Saving Environment to MMC... Writing to redundant MMC(1)... OK
STM32MP> boot
ethernet@5800a000 Waiting for PHY auto negotiation to complete.... done
Using ethernet@5800a000 device
TFTP from server 192.168.2.180; our IP address is 192.168.2.178
Filename 'uImage'.
Load address: 0xc2000000
Loading: #################################################################
#################################################################
#################################################################
#################################################################
#################################################################
#################################################################
#################################################################
#######################T #####################
682.6 KiB/s
done
Bytes transferred = 7312152 (6f9318 hex)
Using ethernet@5800a000 device
TFTP from server 192.168.2.180; our IP address is 192.168.2.178
Filename 'stm32mp157d-atk.dtb'.
Load address: 0xc4000000
Loading: #####
989.3 KiB/s
done
Bytes transferred = 63833 (f959 hex)
Booting kernel from Legacy Image at c2000000 ...
Image Name: Linux-5.4.31
Created: 2024-02-12 6:18:02 UTC
Image Type: ARM Linux Kernel Image (uncompressed)
Data Size: 7312088 Bytes = 7 MiB
Load Address: c2000040
Entry Point: c2000040
Verifying Checksum ... OK
Flattened Device Tree blob at c4000000
Booting using the fdt blob at 0xc4000000
XIP Kernel Image
Loading Device Tree to cffed000, end cffff958 ... OK
Starting kernel ...
Booting Linux on physical CPU 0x0
Linux version 5.4.31 (zgq@zgq-virtual-machine) (gcc version 9.2.1 20191025 (GNU Toolchain for the A-profile Architecture 9.2-2019.12 (arm-9.10))) #4 SMP PREEMPT Mon Feb 12 14:17:47 CST 2024
CPU: ARMv7 Processor [410fc075] revision 5 (ARMv7), cr=10c5387d
CPU: div instructions available: patching division code
CPU: PIPT / VIPT nonaliasing data cache, VIPT aliasing instruction cache
OF: fdt: Machine model: STMicroelectronics STM32MP157D eval daughter
Memory policy: Data cache writealloc
Reserved memory: created DMA memory pool at 0x10000000, size 0 MiB
OF: reserved mem: initialized node mcuram2@10000000, compatible id shared-dma-pool
Reserved memory: created DMA memory pool at 0x10040000, size 0 MiB
OF: reserved mem: initialized node vdev0vring0@10040000, compatible id shared-dma-pool
Reserved memory: created DMA memory pool at 0x10041000, size 0 MiB
OF: reserved mem: initialized node vdev0vring1@10041000, compatible id shared-dma-pool
Reserved memory: created DMA memory pool at 0x10042000, size 0 MiB
OF: reserved mem: initialized node vdev0buffer@10042000, compatible id shared-dma-pool
Reserved memory: created DMA memory pool at 0x30000000, size 0 MiB
OF: reserved mem: initialized node mcuram@30000000, compatible id shared-dma-pool
Reserved memory: created DMA memory pool at 0x38000000, size 0 MiB
OF: reserved mem: initialized node retram@38000000, compatible id shared-dma-pool
cma: Reserved 128 MiB at 0xe8000000
psci: probing for conduit method from DT.
psci: PSCIv1.1 detected in firmware.
psci: Using standard PSCI v0.2 function IDs
psci: MIGRATE_INFO_TYPE not supported.
psci: SMC Calling Convention v1.0
percpu: Embedded 20 pages/cpu s50124 r8192 d23604 u81920
Built 1 zonelists, mobility grouping on. Total pages: 227647
Kernel command line: console=ttySTM0,115200 root=/dev/nfs nfsroot=192.168.2.180:/home/zgq/linux/nfs/rootfs,proto=tcp rw ip=192.168.2.178:192.168.2.180:192.168.2.1:255.255.255.0::eth0:off
Dentry cache hash table entries: 131072 (order: 7, 524288 bytes, linear)
Inode-cache hash table entries: 65536 (order: 6, 262144 bytes, linear)
mem auto-init: stack:off, heap alloc:off, heap free:off
Memory: 759396K/917500K available (11264K kernel code, 869K rwdata, 3408K rodata, 1024K init, 213K bss, 27032K reserved, 131072K cma-reserved, 131068K highmem)
SLUB: HWalign=64, Order=0-3, MinObjects=0, CPUs=2, Nodes=1
rcu: Preemptible hierarchical RCU implementation.
rcu: RCU event tracing is enabled.
Tasks RCU enabled.
rcu: RCU calculated value of scheduler-enlistment delay is 10 jiffies.
NR_IRQS: 16, nr_irqs: 16, preallocated irqs: 16
random: get_random_bytes called from start_kernel+0x31c/0x4f4 with crng_init=0
arch_timer: cp15 timer(s) running at 24.00MHz (virt).
clocksource: arch_sys_counter: mask: 0xffffffffffffff max_cycles: 0x588fe9dc0, max_idle_ns: 440795202592 ns
sched_clock: 56 bits at 24MHz, resolution 41ns, wraps every 4398046511097ns
Switching to timer-based delay loop, resolution 41ns
Console: colour dummy device 80x30
Calibrating delay loop (skipped), value calculated using timer frequency.. 48.00 BogoMIPS (lpj=240000)
pid_max: default: 32768 minimum: 301
Mount-cache hash table entries: 2048 (order: 1, 8192 bytes, linear)
Mountpoint-cache hash table entries: 2048 (order: 1, 8192 bytes, linear)
CPU: Testing write buffer coherency: ok
/cpus/cpu@0 missing clock-frequency property
/cpus/cpu@1 missing clock-frequency property
CPU0: thread -1, cpu 0, socket 0, mpidr 80000000
Setting up static identity map for 0xc0100000 - 0xc0100060
rcu: Hierarchical SRCU implementation.
smp: Bringing up secondary CPUs ...
CPU1: thread -1, cpu 1, socket 0, mpidr 80000001
smp: Brought up 1 node, 2 CPUs
SMP: Total of 2 processors activated (96.00 BogoMIPS).
CPU: All CPU(s) started in SVC mode.
devtmpfs: initialized
VFP support v0.3: implementor 41 architecture 2 part 30 variant 7 rev 5
clocksource: jiffies: mask: 0xffffffff max_cycles: 0xffffffff, max_idle_ns: 19112604462750000 ns
futex hash table entries: 512 (order: 3, 32768 bytes, linear)
pinctrl core: initialized pinctrl subsystem
NET: Registered protocol family 16
DMA: preallocated 256 KiB pool for atomic coherent allocations
hw-breakpoint: found 5 (+1 reserved) breakpoint and 4 watchpoint registers.
hw-breakpoint: maximum watchpoint size is 8 bytes.
Serial: AMBA PL011 UART driver
stm32-pm-domain pm_domain: domain core-ret-power-domain registered
stm32-pm-domain pm_domain: subdomain core-power-domain registered
stm32-pm-domain pm_domain: domains probed
reg-fixed-voltage buck1: Fixed regulator specified with variable voltages
reg-fixed-voltage: probe of buck1 failed with error -22
SCSI subsystem initialized
usbcore: registered new interface driver usbfs
usbcore: registered new interface driver hub
usbcore: registered new device driver usb
pps_core: LinuxPPS API ver. 1 registered
pps_core: Software ver. 5.3.6 - Copyright 2005-2007 Rodolfo Giometti <giometti@linux.it>
PTP clock support registered
EDAC MC: Ver: 3.0.0
Advanced Linux Sound Architecture Driver Initialized.
clocksource: Switched to clocksource arch_sys_counter
thermal_sys: Registered thermal governor 'step_wise'
NET: Registered protocol family 2
tcp_listen_portaddr_hash hash table entries: 512 (order: 0, 6144 bytes, linear)
TCP established hash table entries: 8192 (order: 3, 32768 bytes, linear)
TCP bind hash table entries: 8192 (order: 4, 65536 bytes, linear)
TCP: Hash tables configured (established 8192 bind 8192)
UDP hash table entries: 512 (order: 2, 16384 bytes, linear)
UDP-Lite hash table entries: 512 (order: 2, 16384 bytes, linear)
NET: Registered protocol family 1
RPC: Registered named UNIX socket transport module.
RPC: Registered udp transport module.
RPC: Registered tcp transport module.
RPC: Registered tcp NFSv4.1 backchannel transport module.
hw perfevents: enabled with armv7_cortex_a7 PMU driver, 5 counters available
Initialise system trusted keyrings
workingset: timestamp_bits=14 max_order=18 bucket_order=4
squashfs: version 4.0 (2009/01/31) Phillip Lougher
NFS: Registering the id_resolver key type
Key type id_resolver registered
Key type id_legacy registered
ntfs: driver 2.1.32 [Flags: R/O].
jffs2: version 2.2. (NAND) © 2001-2006 Red Hat, Inc.
fuse: init (API version 7.31)
NET: Registered protocol family 38
Key type asymmetric registered
Asymmetric key parser 'x509' registered
bounce: pool size: 64 pages
Block layer SCSI generic (bsg) driver version 0.4 loaded (major 246)
io scheduler mq-deadline registered
io scheduler kyber registered
STM32 USART driver initialized
brd: module loaded
loop: module loaded
libphy: Fixed MDIO Bus: probed
CAN device driver interface
pegasus: v0.9.3 (2013/04/25), Pegasus/Pegasus II USB Ethernet driver
usbcore: registered new interface driver pegasus
usbcore: registered new interface driver asix
usbcore: registered new interface driver ax88179_178a
usbcore: registered new interface driver cdc_ether
usbcore: registered new interface driver smsc75xx
usbcore: registered new interface driver smsc95xx
usbcore: registered new interface driver net1080
usbcore: registered new interface driver cdc_subset
usbcore: registered new interface driver zaurus
usbcore: registered new interface driver cdc_ncm
ehci_hcd: USB 2.0 'Enhanced' Host Controller (EHCI) Driver
ehci-platform: EHCI generic platform driver
ohci_hcd: USB 1.1 'Open' Host Controller (OHCI) Driver
ohci-platform: OHCI generic platform driver
usbcore: registered new interface driver cdc_acm
cdc_acm: USB Abstract Control Model driver for USB modems and ISDN adapters
usbcore: registered new interface driver usb-storage
i2c /dev entries driver
stm32-cpufreq stm32-cpufreq: Failed to get chip info: -517
sdhci: Secure Digital Host Controller Interface driver
sdhci: Copyright(c) Pierre Ossman
Synopsys Designware Multimedia Card Interface Driver
sdhci-pltfm: SDHCI platform and OF driver helper
ledtrig-cpu: registered to indicate activity on CPUs
usbcore: registered new interface driver usbhid
usbhid: USB HID core driver
arm-smc-mbox mailbox-0: ARM SMC mailbox enabled.
arm-smc-mbox mailbox-1: ARM SMC mailbox enabled.
Unable to get STM32 DDR PMU clock
drop_monitor: Initializing network drop monitor service
NET: Registered protocol family 17
can: controller area network core (rev 20170425 abi 9)
NET: Registered protocol family 29
can: raw protocol (rev 20170425)
can: broadcast manager protocol (rev 20170425 t)
can: netlink gateway (rev 20190810) max_hops=1
Key type dns_resolver registered
ThumbEE CPU extension supported.
Registering SWP/SWPB emulation handler
registered taskstats version 1
Loading compiled-in X.509 certificates
arm-scmi firmware:scmi-0: SCMI Protocol v2.0 'ST:' Firmware version 0x0
Unable to get STM32 DDR PMU clock
debugfs: Directory 'cpu0' with parent 'opp' already present!
Unable to get STM32 DDR PMU clock
stm32-mdma 58000000.dma: STM32 MDMA driver registered
stm32-dma 48000000.dma: STM32 DMA driver registered
stm32-dma 48001000.dma: STM32 DMA driver registered
reg11: supplied by regulator-dummy
reg18: supplied by regulator-dummy
usb33: supplied by regulator-dummy
stm_thermal 50028000.thermal: stm_thermal_probe: Driver initialized successfully
debugfs: Directory 'cpu0' with parent 'opp' already present!
stm32-crc32 58009000.crc: Initialized
stm32-hash 54002000.hash: will run requests pump with realtime priority
random: fast init done
stm32-hash 54002000.hash: Init HASH done HW ver 23 DMA mode 1
stm32-ddr-pmu: probed (ID=0x00140061 VER=0x00000010), DDR@533MHz
random: crng init done
/soc/interrupt-controller@5000d000: bank0
/soc/interrupt-controller@5000d000: bank1
/soc/interrupt-controller@5000d000: bank2
stm32mp157-pinctrl soc:pin-controller@50002000: GPIOA bank added
stm32mp157-pinctrl soc:pin-controller@50002000: GPIOB bank added
stm32mp157-pinctrl soc:pin-controller@50002000: GPIOC bank added
stm32mp157-pinctrl soc:pin-controller@50002000: GPIOD bank added
stm32mp157-pinctrl soc:pin-controller@50002000: GPIOE bank added
stm32mp157-pinctrl soc:pin-controller@50002000: GPIOF bank added
stm32mp157-pinctrl soc:pin-controller@50002000: GPIOG bank added
stm32mp157-pinctrl soc:pin-controller@50002000: GPIOH bank added
stm32mp157-pinctrl soc:pin-controller@50002000: GPIOI bank added
stm32mp157-pinctrl soc:pin-controller@50002000: GPIOJ bank added
stm32mp157-pinctrl soc:pin-controller@50002000: GPIOK bank added
stm32mp157-pinctrl soc:pin-controller@50002000: Pinctrl STM32 initialized
stm32mp157-pinctrl soc:pin-controller-z@54004000: GPIOZ bank added
stm32mp157-pinctrl soc:pin-controller-z@54004000: Pinctrl STM32 initialized
stm32-usart 40010000.serial: interrupt mode for rx (no dma)
stm32-usart 40010000.serial: interrupt mode for tx (no dma)
40010000.serial: ttySTM0 at MMIO 0x40010000 (irq = 47, base_baud = 4000000) is a stm32-usart
printk: console [ttySTM0] enabled
stm32-dwmac 5800a000.ethernet: PTP uses main clock
stm32-dwmac 5800a000.ethernet: no reset control found
stm32-dwmac 5800a000.ethernet: No phy clock provided...
stm32-dwmac 5800a000.ethernet: User ID: 0x40, Synopsys ID: 0x42
stm32-dwmac 5800a000.ethernet: DWMAC4/5
stm32-dwmac 5800a000.ethernet: DMA HW capability register supported
stm32-dwmac 5800a000.ethernet: RX Checksum Offload Engine supported
stm32-dwmac 5800a000.ethernet: TX Checksum insertion supported
stm32-dwmac 5800a000.ethernet: Wake-Up On Lan supported
stm32-dwmac 5800a000.ethernet: TSO supported
stm32-dwmac 5800a000.ethernet: Enable RX Mitigation via HW Watchdog Timer
stm32-dwmac 5800a000.ethernet: device MAC address 00:04:9f:04:d2:36
stm32-dwmac 5800a000.ethernet: TSO feature enabled
libphy: stmmac: probed
stm32_rtc 5c004000.rtc: registered as rtc0
stm32_rtc 5c004000.rtc: Date/Time must be initialized
stm32_rtc 5c004000.rtc: registered rev:1.2
mmci-pl18x 58005000.sdmmc: mmc0: PL180 manf 53 rev2 at 0x58005000 irq 43,0 (pio)
mmci-pl18x 58007000.sdmmc: mmc1: PL180 manf 53 rev2 at 0x58007000 irq 44,0 (pio)
mmc0: host does not support reading read-only switch, assuming write-enable
stm32-ipcc 4c001000.mailbox: ipcc rev:1.0 enabled, 6 chans, proc 0
mmc0: new high speed SDHC card at address 1234
stm32_rtc 5c004000.rtc: setting system clock to 2000-01-01T00:32:54 UTC (946686774)
stm32-dwmac 5800a000.ethernet eth0: PHY [stmmac-0:00] driver [YT8511 Gigabit Ethernet]
mmcblk0: mmc0:1234 SA16G 14.4 GiB
mmcblk0: p1
dwmac4: Master AXI performs any burst length
stm32-dwmac 5800a000.ethernet eth0: No Safety Features support found
stm32-dwmac 5800a000.ethernet eth0: IEEE 1588-2008 Advanced Timestamp supported
stm32-dwmac 5800a000.ethernet eth0: registered PTP clock
stm32-dwmac 5800a000.ethernet eth0: configuring for phy/rgmii-id link mode
mmc1: new high speed MMC card at address 0001
mmcblk1: mmc1:0001 8GTF4R 7.28 GiB
mmcblk1boot0: mmc1:0001 8GTF4R partition 1 4.00 MiB
mmcblk1boot1: mmc1:0001 8GTF4R partition 2 4.00 MiB
mmcblk1rpmb: mmc1:0001 8GTF4R partition 3 512 KiB, chardev (242:0)
mmcblk1: p1 p2
stm32-dwmac 5800a000.ethernet eth0: Link is Up - 100Mbps/Full - flow control rx/tx
IP-Config: Complete:
device=eth0, hwaddr=00:04:9f:04:d2:36, ipaddr=192.168.2.178, mask=255.255.255.0, gw=192.168.2.1
host=192.168.2.178, domain=, nis-domain=(none)
bootserver=192.168.2.180, rootserver=192.168.2.180, rootpath=
ALSA device list:
No soundcards found.
VFS: Mounted root (nfs filesystem) on device 0:16.
devtmpfs: mounted
Freeing unused kernel memory: 1024K
Run /sbin/init as init process
can't run '/etc/init.d/rcS': No such file or directory
Please press Enter to activate this console.
/ #
6)、在串口终端，输入"ls回车"
串口可以执行"ls"命令
2、解决"can't run '/etc/init.d/rcS': No such file or directory"
rcS是个shell脚本，Linux内核启动以后需要启动一些服务，而rcS就是规定启动哪些文件的脚本文件。因此，需要在rootfs中创建"/etc/init.dhcS"文件。
1)、在串口终端，输入"ls回车"
输入"cd etc/回车",切换得到"etc"目录
输入"ls回车", 查询"etc"目录下的文件和文件夹
输入"mkdir init.d回车",创建"init.d"目录
输入"ls回车", 查询"etc"目录下的文件和文件夹
输入"cd init.d/回车",切换得到"init.d"目录
2)、输入"vi rcS回车",创建"rcS"文件
#!/bin/sh
PATH=/sbin:/bin:/usr/sbin:/usr/bin:$PATH
LD_LIBRARY_PATH=$LD_LIBRARY_PATH:/lib:/usr/lib
export PATH LD_LIBRARY_PATH
mount -a
mkdir /dev/pts
mount -t devpts devpts /dev/pts
echo /sbin/mdev > /proc/sys/kernel/hotplug
3)、按"ESC键"，输入":wq回车"，保存退出
4)、输入"chmod 777 rcS回车"，给rcS赋可执行权限
输入"ls回车", 查询"init.d"目录下的文件和文件夹
输入"reboot回车"，重启
运行结果：
stm32-dwmac 5800a000.ethernet eth0: Link is Up - 100Mbps/Full - flow control rx/tx
IP-Config: Complete:
device=eth0, hwaddr=00:04:9f:04:d2:36, ipaddr=192.168.2.178, mask=255.255.255.0, gw=192.168.2.1
host=192.168.2.178, domain=, nis-domain=(none)
bootserver=192.168.2.180, rootserver=192.168.2.180, rootpath=
ALSA device list:
No soundcards found.
VFS: Mounted root (nfs filesystem) on device 0:16.
devtmpfs: mounted
Freeing unused kernel memory: 1024K
Run /sbin/init as init process
mount: can't read '/etc/fstab': No such file or directory
/etc/init.d/rcS: line 11: can't create /proc/sys/kernel/hotplug: nonexistent directory
Please press Enter to activate this console.
3、解决"mount: can't read '/etc/fstab': No such file or directory"
1)、在串口终端，输入"ls回车"
输入"cd etc/回车",切换得到"etc"目录
输入"ls回车", 查询"etc"目录下的文件和文件夹
输入"vi fstab回车",创建"fstab"文件
2)、添加内容如下：
#<file system> <mount point> <type> <options> <dump> <pass>
proc /proc proc defaults 0 0
tmpfs /tmp tmpfs defaults 0 0
sysfs /sys sysfs defaults 0 0
3)、按"ESC键"，输入":wq回车"，保存退出
输入"ls回车", 查询"etc"目录下的文件和文件夹
输入"reboot回车",重启
运行结果：
VFS: Mounted root (nfs filesystem) on device 0:16.
devtmpfs: mounted
Freeing unused kernel memory: 1024K
Run /sbin/init as init process
/etc/init.d/rcS: line 11: can't create /proc/sys/kernel/hotplug: nonexistent directory
Please press Enter to activate this console.
4、创建"/etc/inittab"
1)、在串口终端，输入"ls回车"
输入"cd etc/回车",切换得到"etc"目录
输入"ls回车", 查询"etc"目录下的文件和文件夹
输入"vi inittab回车",创建"inittab"文件
2)、添加内容如下：
#etc/inittab
::sysinit:/etc/init.d/rcS
#系统启动以后运行/etc/init.drcs 这个脚本文件
console::askfirst:-/bin/sh
#将console作为控制台终端，也就是 ttySTM0
::restart:/sbin/init
#重启的话运行/sbin/imit
::ctrlaltdel:/sbin/reboot
#按下ctrl+alt+del组合键就运行/sbinreboot，看来ctrl+alt+del组合键用于重启系统
::shutdown:/bin/umount -a -r
#关机的时候执行/bin/umount，也就是卸载各个文件系统
::shutdown:/sbin/swapoff -a
#关机的时候执行/sbin/swapof，也就是关闭交换分区
3)、按"ESC键"，输入":wq回车"，保存退出
输入"ls回车", 查询"etc"目录下的文件和文件夹
至此，根文件系统要创建的文件就已经全部完成了。
5、使能内核uevet helper
1)、打开虚拟机终端
输入"ls回车"
输入"cd linux/回车"，切换到"linux"目录
输入"ls回车"，列出"linux"目录下的文件和文件夹
输入"cd atk-mp1/回车"，切换到"atk-mp1"目录
输入"ls回车"，列出"atk-mp1"目录下的文件和文件夹
输入"cd linux/回车"，切换到"linux"目录
输入"ls回车"，列出"linux"目录下的文件和文件夹
输入"cd my_linux/回车"，切换到"my_linux"目录
输入"ls回车"，列出"my_linux"目录下的文件和文件夹
输入"cd linux-5.4.31/回车"，切换到"linux-5.4.31"目录
输入"ls回车"，列出"linux-5.4.31"目录下的文件和文件夹
输入"make menuconfig回车"，打开linux的图形配置化界面
2)、移动向下光标键，找到"Device Drivers"
3)、按回车键，移动向下光标键，找到"Generic Driver Options"
4)、按回车键，移动向下光标键，找到"Support for uevent helper"，按"Y"
5)、按"ESC键"，直到出现下面的对话框
6)、按"Y"保存
输入"make menuconfig回车"，打开linux的图形配置化界面
移动向右光标键至"Save"
7)、按"回车键"
8)、删除".config"，改为"./arch/arm/configs/stm32mp1_atk_defconfig"
9)、移动向下光标键至"Ok"，按"O"保存
10)、按"ESC键"关闭对话框
由于设备树dtbs没有被修改，我们只需编译uImage
输入"make uImage LOADADDR=0XC2000040 -j8回车"
#编译镜像文件，linux内核在DDR中的加载地址为0XC2000040，-j8表示采用8线程编译
11)、输入"cp arch/arm/boot/uImage /home/zgq/linux/tftpboot/ -f回车"，执行文件拷贝；
12)、在串口输入"reboot回车"，重启
运行结果：
mmcblk1: p1 p2
stm32-dwmac 5800a000.ethernet eth0: Link is Up - 100Mbps/Full - flow control rx/tx
IP-Config: Complete:
device=eth0, hwaddr=00:04:9f:04:d2:36, ipaddr=192.168.2.178, mask=255.255.255.0, gw=192.168.2.1
host=192.168.2.178, domain=, nis-domain=(none)
bootserver=192.168.2.180, rootserver=192.168.2.180, rootpath=
ALSA device list:
No soundcards found.
VFS: Mounted root (nfs filesystem) on device 0:16.
devtmpfs: mounted
Freeing unused kernel memory: 1024K
Run /sbin/init as init process
Please press Enter to activate this console.
运行正确。
6、在根文件系统下创建"drivers"目录，将来编写的驱动就可以放到"drivers"目录中
在串口终端，输入"ls回车"
输入"mkdir drivers回车"，创建"drivers"目录
输入"ls回车"，查询根目录下的文件和文件夹
7、软件运行测试
1)、输入"ls回车"
输入"cd linux/回车"，切换到"linux"目录
输入"ls回车"，列出"linux"目录下的文件和文件夹
输入"cd nfs/回车"，切换到"nfs"目录
输入"ls回车"，列出"nfs"目录下的文件和文件夹
输入"vi hello.c回车"，创建"hello.c"
2)、输入内容如下：
#include <stdio.h>
int main(void)
{
while(1) {
printf("hello world!\r\n"); //串口输出"hello world!"
sleep(2); //延时2妙
}
return 0;
}
3)、按"ESC键"，输入":wq"保存退出
输入"arm-none-linux-gnueabihf-gcc hello.c -o hello回车"，使用交叉编译"hello.c"
输入"file hello回车"，查看hello的文件类型以及编码格式
输入"sudo cp hello /home/zgq/linux/nfs/rootfs/drivers/回车"，将"hello"拷贝到"/home/zgq/linux/nfs/rootfs/drivers/"目录中
输入"ls回车"，列出"linux"目录下的文件和文件夹
输入"cd rootfs/回车"，切换到"rootfs"目录
输入"ls回车"，列出"rootfs"目录下的文件和文件夹
输入"cd drivers/回车"，切换到"drivers"目录
输入"ls回车"，列出"drivers"目录下的文件和文件夹
4)、在串口终端输入"cd drivers/回车"
输入"ls/回车"
输入"./hello回车"
得到下面的界面
5)、按"CTRL+C"暂停
输入"./hello &回车"将"hello"放到后台执行
6)、关闭后台运行，输入"ps回车"查看"hello"的ID
7)、输入"kill -9 154回车"，就可以删除"hello运行"
8)、再次输入"ps回车"查看"hello"是不是没有了
8、中文字符测试
1)、输入"cd ..回车"，返回到"/linux/nfs/rootfs"目录下
输入"mkdir 中文测试"，创建"中文测试目录"
输入"ls回车"
输入"cd 中文测试"
输入"vi 中文测试.txt"，这个中文文档只能建在中文目录下
输入内容如下：
这是中文测试文档
测试时间:2024年2月14
按"ESC键"，输入":wq回车"，保存
2)、在串口终端
输入"ls"
输入"cd 中文测试"
输入"ls"
输入"cat 中文测试.txt"
9、开机自动启动hello程序
1)、输入"cd 中文测试.."
输入"ls"
输入"cd etc/"
输入"ls"
输入"cd init.d/"
输入"ls"
输入"vi rsS"
添加内容如下：
cd /drivers
./hello &
cd /
2)、输入"reboot"重启
3)、测试正确后，先停止hello程序，然后打开"etc/init.d/rcS"修改如下图：
4)、按"ESC键"，输入":wq回车"，保存
10、使用ping命令测试外网连接
1)、在rootfs中新建文件/etc/resolv.conf,然后在里面输入如下内容:
输入"ls"
输入"cd etc/"
输入"ls"
输入"vi resolv.conf"
2)、输入内容如下：
meserver 114.114.114.114
nameserver 192.168.2.1
3)、按"ESC键"，输入":wq回车"，保存
输入"reboot"，重启
输入"ping www.baidu.com"
执行结果如下：
至此，"根文件系统"制作完成了。