By Toradex 秦海

简介

随着工业发展，嵌入式设备接入网络的需求日益增多，在没有有线或者无线以太网的环境下，直接通过3G/4G Modem连接运营商网络来接入互联网不失为一个好方法，本文就着重介绍基于ARM平台的嵌入式设备在Embedded Linux下使用3G/4G Modem的方法。

目前市面上的3G/4G modem和主机的连接方式主要有串口、USB和mini-PCIE，串口模块比较传统且使用比较简单，而mini-PCIE在工业设备中目前应用还不广泛，因此本文使用USB 3G/4G modem来进行演示。

硬件准备

嵌入式平台基于Toradex Colibri i.MX6工业产品级ARM核心板搭配Colibri开发载板，Embedded Linux采用Toradex官方发布兼容Yocto Project 的Linux V2.5版本。

3G Modem使用华为 E303s WCDMA Modem，支持中国联通的3G网络

Linux Kernel准备

关于Linux kernel源代码下载及基本编译更新操作请参考这里，本文不再赘述，只简单列出操作如下：

a). 下载Linux kernel源代码

b). 下载安装Toolchain，并link到 “ ~/gcc-linaro “ 目录

$ wget http://releases.linaro.org/14.11/components/toolchain/binaries/arm-linux-gnueabihf/gcc-linaro-4.9-2014.11-x86_64_arm-linux-gnueabihf.tar.xz

$ tar xvf gcc-linaro-4.9-2014.11-x86_64_arm-linux-gnueabihf.tar.xz

$ ln -s gcc-linaro-4.9-2014.11-x86_64_arm-linux-gnueabihf gcc-linaro

 

c). 设置环境变量

$ export ARCH=arm

$ export PATH=~/gcc-linaro/bin/:$PATH

$ export CROSS_COMPILE=arm-linux-gnueabihf-

 

d). 配置

$ make colibri_imx6_defconfig

$ make menuconfig      //添加下面列出功能

--------------------

[*] Network device support  --->

       <*>   PPP (point-to-point protocol) support

       <*>     PPP BSD-Compress compression

        <*>     PPP Deflate compression

       [*]     PPP filtering

       <*>     PPP MPPE compression (encryption)

       [*]     PPP multilink support

       <*>     PPP over Ethernet

       <*>     PPP support for async serial ports

       <*>     PPP support for sync tty ports

 

[*] USB support  --->

       <*>     USB Modem (CDC ACM) support

 

[*] USB support  --->

    <*>   USB Serial Converter support  --->

              <*>   USB driver for GSM and CDMA modems

--------------------

 

e). 重新编译kernel image

$ make -j3 uImage LOADADDR=10008000 2>&1 | tee build.log

 

f). 升级目标板

根据本章节开始提供的参考升级目标板到新的kernel image

相关软件准备

1). PPP

Toradex image默认已经安装，如果其他ARM平台image也是基于Yocto/OpenEmbedded环境编译，可以在local.conf文件中添加如下选项后编译

-----------------

IMAGE_INSTALL_append = " ppp"

-----------------

2). usb-modesiwtch-2.3.0

a). 需要libusb-1.0.x，先从这里下载源文件并解压

b). 使用上一章节配置的ToolChain如下设置交叉编译libusb

$ sudo CC="/home/xxx/gcc-linaro/bin/arm-linux-gnueabihf-gcc" CXX="/home/xxx/gcc-linaro/bin/arm-linux-gnueabihf-g++" ./configure --host=arm-linux-gnueabihf --prefix=/home/xxx/gcc-linaro --disable-udev

$ make

$ make install

c). 从这里下载usb-modesiwtch并解压

d). 如下修改usb-modesiwtch 目录下Makefile

----------------

CC          = ~/gcc-linaro/bin/arm-linux-gnueabihf-gcc

CFLAGS      += -Wall -I/home/xxx/gcc-linaro/include -L/home/xxx/gcc-linaro/lib

----------------

e).交叉编译usb-modesiwtch

$ make

f). 从这里下载usb-modeswitch-data，和上面步骤编译出的usb-modesiwtch可执行文件一起上传到目标板

配置Modem连接网络

目前比较新的3G/4G都支持Ethernet模式和Fallback模式，而老一些的模块只支持Fallback模式，请根据所需模块情况自行参考下面操作。

1). Ethernet模式

a). 将E303s 3G Modem连接目标板，由于Modem上包含为了给Windows系统提供驱动而部署的存储分区，Linux默认将设备识别成USB Mass Storage设备

root@colibri-imx6:/home# lsusb

Bus 001 Device 004: ID 12d1:1f01 Huawei Technologies Co., Ltd. E353/E3131 (Mass storage mode)

……

b). 如下修改usb-modeswitch-data-20160112/usb_modeswitch.d目录下的12d1:1f01文件

-----------------------

# Huawei E303s Ethernet Mode

DefaultVendor=0x12d1

DefaultProduct=0x1f01

TargetVendor=0x12d1

TargetProduct=0x14db

MessageEndPoint = "0x01"

MessageContent="55534243123456780000000000000a11062000000000000100000000000000"

------------------------

c). 使用usb-modeswitch工具将modem设置为Ethernet mode

root@colibri-imx6:/home# ./usb_modeswitch -c 12d1:1f01

……

root@colibri-imx6:/home# [  840.027676] usb 1-1.1: USB disconnect, device number 4

[  840.284299] usb 1-1.1: new high-speed USB device number 6 using ci_hdrc

[  840.427810] cdc_ether 1-1.1:1.0 eth1: register 'cdc_ether' at usb-ci_hdrc.0-1.1, CDC Ethernet Device, 58:2c:80:13:92:63

 

lsusb查看

root@colibri-imx6:/home# lsusb

Bus 001 Device 005: ID 12d1:14db Huawei Technologies Co., Ltd. E353/E3131

……

d). 查看网络，出现eth1，正确获取ip并连接到网络，下面就可以用使用以太网同样方法使用网络了

root@colibri-imx6:/home# ifconfig

……

eth1      Link encap:Ethernet  HWaddr 58:2C:80:13:92:63 

          inet addr:192.168.1.100  Bcast:192.168.1.255  Mask:255.255.255.0

          inet6 addr: fe80::5a2c:80ff:fe13:9263/64 Scope:Link

          UP BROADCAST RUNNING MULTICAST  MTU:1500  Metric:1

          RX packets:37 errors:0 dropped:0 overruns:0 frame.:0

          TX packets:69 errors:0 dropped:0 overruns:0 carrier:0

          collisions:0 txqueuelen:1000

          RX bytes:6899 (6.7 KiB)  TX bytes:10381 (10.1 KiB)

……

e). 验证网络连接

root@colibri-imx6:/home# ping www.baidu.com

PING www.baidu.com (61.135.169.121): 56 data bytes

64 bytes from 61.135.169.121: seq=0 ttl=51 time=88.261 ms

64 bytes from 61.135.169.121: seq=1 ttl=51 time=77.998 ms

64 bytes from 61.135.169.121: seq=2 ttl=51 time=68.410 ms

64 bytes from 61.135.169.121: seq=3 ttl=51 time=68.242 ms

64 bytes from 61.135.169.121: seq=4 ttl=51 time=68.166 ms

2). Fallback模式

有一些较老型号的2G/3G Modem只支持这个模式，无需再用usb-modeswitch转换，可以直接参考下面转换后的操作部分。

a). 如下修改usb-modeswitch-data-20160112/usb_modeswitch.d目录下的12d1:1f01文件

-----------------------

# Huawei E303s Fallback Mode

DefaultVendor=0x12d1

DefaultProduct=0x1f01

TargetVendor=0x12d1

TargetProduct=0x1001

MessageEndPoint = "0x01"

MessageContent="55534243123456780000000000000011063000000100010000000000000000"

NoDriverLoading=0

------------------------

b). 使用usb-modeswitch工具将modem设置为Fallback mode

root@colibri-imx6:/home# ./usb_modeswitch -c 12d1\:1f01

……

root@colibri-imx6:/home# [ 2090.566190] usb 1-1.1: new high-speed USB device number 8 using ci_hdrc

[ 2090.701092] option 1-1.1:1.0: GSM modem (1-port) converter detected

[ 2090.713488] usb 1-1.1: GSM modem (1-port) converter now attached to ttyUSB0

[ 2090.723517] option 1-1.1:1.1: GSM modem (1-port) converter detected

[ 2090.731817] usb 1-1.1: GSM modem (1-port) converter now attached to ttyUSB1

[ 2090.740318] option 1-1.1:1.2: GSM modem (1-port) converter detected

[ 2090.748184] usb 1-1.1: GSM modem (1-port) converter now attached to ttyUSB

 

lsusb 查看

root@colibri-imx6:/home# lsusb

Bus 001 Device 008: ID 12d1:1001 Huawei Technologies Co., Ltd. E169/E620/E800 HSDPA Modem

……

c). 测试连接

root@colibri-imx6:/home# ls -l /dev/ttyUSB*

crw-rw----    1 root     dialout   188,   0 Apr 11 09:49 /dev/ttyUSB0

crw-rw----    1 root     dialout   188,   1 Apr 11 09:49 /dev/ttyUSB1

crw-rw----    1 root     dialout   188,   2 Apr 11 09:49 /dev/ttyUSB2

 

root@colibri-imx6:/home# minicom -D /dev/ttyUSB0

------------------

Welcome to minicom 2.7

OPTIONS: I18n

Compiled on Nov  3 2015, 04:06:26.

Port /dev/ttyUSB0, 09:53:44

Press CTRL-A Z for help on special keys

 

AT

OK

--------------------

d). 编写ppp连接配置文件wcdma, wcdma-chat-connect和wcdma-chat-disconnect

root@colibri-imx6:/etc/ppp/peers# vi wcdma

-----------------

nodetach

lock

/dev/ttyUSB0

115200

user "card"

password "card"

crtscts

#hide-password

show-password

usepeerdns

noauth

noipdefault

novj

novjccomp

noccp

defaultroute

ipcp-accept-local

ipcp-accept-remote

connect '/usr/sbin/chat -s -v -f /etc/ppp/peers/wcdma-chat-connect'

disconnect '/usr/sbin/chat -s -v -f /etc/ppp/peers/wcdma-chat-disconnect'

----------------------

 

root@colibri-imx6:/etc/ppp/peers# vi wcdma-chat-connect

--------------------

ABORT "BUSY"

ABORT "NO CARRIER"

ABORT "NO DIALTONE"

ABORT "ERROR"

ABORT "NO ANSWER"

TIMEOUT 120

"" AT

OK \rATZ

OK \rAT+CGDCONT=1,"IP","3gnet",,0,0

OK-AT-OK ATDT*99#

CONNECT \d\c

--------------------------

 

root@colibri-imx6:/etc/ppp/peers# vi wcdma-chat-disconnect

-----------------------

ABORT "ERROR"

ABORT "NO DIALTONE"

SAY "\NSending break to the modem\n"

""\k"

""+++ATH"

SAY "\nGood bay\n"

---------------------------

e). 连接网络

root@colibri-imx6:/etc/ppp/peers# pppd call wcdma

……

ATDT*99#^M^M

CONNECT

 -- got it

 

send (\d)

Serial connection established.

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