Implementation of Ti am335x industrial control module network and file system nfs

The verification of this content uses yingpengfei embedded CoM-335x Core module and Evaluation Board EAC-335X, The brief introduction is as follows ：

1 summary

Software debugging is a necessary stage in the product development life cycle , Include kernel 、 The root file system 、 Application software, etc . The usual practice is to burn first BootLoader、 kernel 、 The root file system , Re debug application software . During the debugging phase, you may need to burn the kernel frequently 、 Root file or download application , This will take a lot of time . Download the kernel and mount the root file system through the network , It can solve the problem of frequent burning .

This manual , It mainly introduces how to pass TFTP Download the kernel and mount NFS The root file system .

Operating environment ：

• platform ：EVB-335x
• operating system ：Ubuntu 16.04server 64-bit （ Kernel version 4.4.0-131-generic）
• nfs：nfs-kernel-server_1.2.8-9ubuntu12_amd64 

2 The software requirements

NFS The agreement includes version 2、version 3、 version 4 Three versions （ Hereinafter referred to as NFSv2、NFSv3、NFSv4）, It should be implemented when the motherboard starts the kernel NFS Mount the file system , Must ensure u-boot、kernel And NFS server The versions are consistent .

2.1 u-boot NFS Instructions

Support NFS Instructions , To configure u-boot To be defined ：

#define CONFIG_CMD_NFS //u-boot The default support NFS, stay u-boot Source code include/config_cmd_default.h View in

#define CONFIG_NFSBOOTCOMMAND // You can configure files at the board level include/configs/com335x.h In the definition of （ It's not necessary , This configuration is used for ease of understanding , Because it knows its meaning by seeing its name ）. If this item is defined ,u-boot  In the environment variable “nfsboot=” Parameters , by nfsboot Assignment as NFS Configuration of .

explain ：

1、U-boot 2014.04（COM-335x Use this version ） Support NFSv2, stay u-boot Source code net/nfs.c View in , Such as code list 2-1 Shown （ In red ）;

Code list 2-1

static void

rpc_req(int rpc_prog, int rpc_proc, uint32_t *data, int datalen)

{

  Of ubuntu 16.04 host , Because the default does not support NFSv2, So set compatibility , stay “2.3 NFS server matters needing attention ” Described in the .

3、 The new version of the u-boot Supported by NFS Higher protocol version , for example u-boot 2018.01 The default support NFSv2, If the host does not support NFSv2, Then use NFSv3.

4、 Kernel version matching problem , see “2.2 kernel To configure ”.

5、NFS The revision of the version is not simple “ Code list 2-1” Medium pkt.u.call.rpcvers = htonl(2);  And pkt.u.call.vers = htonl(2);  Value , It can be compatible with other versions NFS. Besides , The new version u-boot The workload of transplantation is heavy . therefore , Recommended in the NFS server End solve the problem of version compatibility .

2.2 kernel To configure

The kernel needs to support NFS Type root file system . Execute in the root directory of the kernel source code ：

make ARCH=arm menuconfig

Choose in turn

File systems  --->

[*] Network File Systems  --->

--- Network File Systems

<*>   NFS client support

[*]     NFS client support for NFS version 3

[*]     NFS client support for the NFSv3 ACL protocol extension

[*]     NFS client support for NFS version 4

[*]       NFS client support for NFSv4.1 (EXPERIMENTAL)

[*]   Root file system on NFS

Configuration is shown in figure 2-2 Shown .

chart 2-2

  explain ： When chosen NFS client support , Namely support NFSv2.NFSv3、NFSv4、NFSv4.1 Optional , It depends on the actual situation .

Besides , Still need to choose kernel level autoconfiguration. Choose in turn ：

[*] Networking support  --->

--- Networking support

[*]   IP: kernel level autoconfiguration

Pictured 2-3 Shown ：

chart 2-3

2.3 NFS server matters needing attention

build NFS server Please refer to Ubuntu Official website .

COM-335x Of U-boot Supported by NFS v2 edition , and Ubuntu 16.04 Support NFS v4 edition . Due to version incompatibility , When mounting NFS File system , Appear as shown in figure 2-4 The error shown .

chart 2-4

  modify “/etc/default/nfs-kernel-server” file , Make it compatible with NFS v2 edition , Add the following statement at the end of the file , Pictured 2-5 Shown .

RPCNFSDOPTS="--nfs-version 2,3,4 --debug --syslog"

chart 2-5

  To configure NFS server, Use the document editing tool to open /etc/exports , Set directories respectively 、 visit IP、 Options （ Usually set permissions, etc ）, Pictured 2-6 Shown .

        chart 2-6

                                                                  

explain ：

/home/daniel/rootfs  Appoint NFS File system load directory ;

* Set access IP,* On behalf of all IP, It can also be a host or a IP paragraph （ for example 192.168.x.x）;

（rw,sync,no_root_squash） Set permissions and other options , Set according to the demand .

2.4 other

TFTP For downloading kernel images , Set up in NFS server On the same host , Please refer to Ubuntu Official website .

3 Implementation process

With NVM Storage u-boot Of COM-335x For example , Brief introduction NFS The implementation process of file mounting .

1、 Prepare the kernel and root file system ：

Put the kernel （uImage） Save to TFTP To configure （/etc/default/tftpd-hpa file ） Specified directory , Pictured 3-1 Shown ,TFTP_DIRECTORY The value is TFTP The directory of the server .

chart 3-1

  Unzip the root file system to /etc/exports The directory specified , Pictured 3-2 Shown .

chart 3-2

explain : Replace the kernel , Replace uImage File can ; The application is saved to the root file system .

2、 burn u-boot

erase Nand Flash, Will be used to start NFS Of MLO And u-boot.img Save to SD The root directory of the card , Power on and automatically burn u-boot. Burn complete , see u-boot Environment variables of （env） To configure , Pictured 3-3 Shown .

chart 3-3

 NFS Introduction to environment variable parameters , As shown in the table 3-1 Shown ：

surface 3-1

serverip	NFS server IP（ necessary ）
ipaddr	a main board IP（ necessary ）
gatewayip	gateway （ It's not necessary , It is recommended to set ）
netmask	Subnet mask （ necessary ）
hostname	Host name （ It's not necessary ）
netdev	Network devices （ It's not necessary ）, for example eth0.
rootpath	NFS Save directory of root file system （ necessary ）

here , chart 3-3 The configuration in may not meet the requirements , for example rootpath、serverip etc. . Use according to the actual situation setenv  Instruction configuration ：

setenv  rootpath /your/dirctory/rootfs

setenv serverip 192.168.1.x

saveenv ß---- Setup completed , use saveenv preservation , Unsaved settings are only valid once

After the setting is correct , Input boot or run bootcmd Start the system , Or power on again .

3、 see NFS

After system startup , see NFS Mounting of the root file system , And file system directory structure . Pictured 3-4 Shown ：

chart 3-4

  The information in the figure is displayed normally , It means NFS Start up .