硬件描述：EC20模块封装成标准的PCIe接口，和系统之家通讯主要通过usb通讯。
系统描述：此处使用的是Linux 3.0.1。
一、驱动支持
首先需要对Linux内核驱动做一定的修改，使操作系统能够支持EC20。
1. Add VID add PID
File: [KERNEL]/drivers/usb/serial/option.c
#if 1 //Added by Quectel{ USB_DEVICE(0x05C6, 0x9090) }, /* Quectel UC15 */{ USB_DEVICE(0x05C6, 0x9003) }, /* Quectel UC20 */{ USB_DEVICE(0x05C6, 0x9215) }, /* Quectel EC20 */{ USB_DEVICE(0x2C7C, 0x0125) }, /* Quectel EC25/EC20 R2.0 */{ USB_DEVICE(0x2C7C, 0x0121) }, /* Quectel EC21 */#endif
2. Add the Zero Packet Mechanism
As required by the USB protocol, you need to add the mechanism for processing zero packets during bulkout transmission.
File: [KERNEL]/drivers/usb/serial/usb_wwan.c
static struct urb *usb_wwan_setup_urb(struct usb_serial *serial, int endpoint,int dir, void *ctx, char *buf, int len,void (*callback) (struct urb *)){struct urb *urb;if (endpoint == -1)return NULL; /* endpoint not needed */urb = usb_alloc_urb(0, GFP_KERNEL); /* No ISO */if (urb == NULL) {dbg("%s: alloc for endpoint %d failed.", __func__, endpoint);return NULL;}/* Fill URB using supplied data. */usb_fill_bulk_urb(urb, serial->dev,usb_sndbulkpipe(serial->dev, endpoint) | dir,buf, len, callback, ctx);#if 1// .3.7 add by zhaoxiaodongif (dir == USB_DIR_OUT) {struct usb_device_descriptor *desc = &serial->dev->descriptor;if (desc->idVendor == cpu_to_le16(0x05C6) && desc->idProduct == cpu_to_le16(0x9090))urb->transfer_flags |= URB_ZERO_PACKET;if (desc->idVendor == cpu_to_le16(0x05C6) && desc->idProduct == cpu_to_le16(0x9003))urb->transfer_flags |= URB_ZERO_PACKET;if (desc->idVendor == cpu_to_le16(0x05C6) && desc->idProduct == cpu_to_le16(0x9215))urb->transfer_flags |= URB_ZERO_PACKET;if (desc->idVendor == cpu_to_le16(0x2C7C))urb->transfer_flags |= URB_ZERO_PACKET;}#endif return urb;}
3. Add Reset Resume
Some USB host controllers/USB hubs will lost power or be reset when MCU entering into suspend/sleep
mode, and they cannot resume USB devices when MCU exiting from suspend/sleep mode; instead, they
will operate reset-resume. You should add the following statements.
For Linux Kernel Version newer than 3.4:
File: [KERNEL]/drivers/usb/serial/option.c
static struct usb_serial_driver option_1port_device = {……#ifdef CONFIG_PM.suspend = usb_wwan_suspend,.resume = usb_wwan_resume,#if 1 //Added by Quectel.reset_resume = usb_wwan_resume,#endif#endif};
For Linux Kernel Version older than 3.5:
File: [KERNEL]/drivers/usb/serial/ usb-serial.c
static struct usb_driver usb_serial_driver = {.name ="usbserial",.probe = usb_serial_probe,.disconnect = usb_serial_disconnect,.suspend = usb_serial_suspend,.resume = usb_serial_resume,#if 1// .3.7 add by zhaoxiaodong.reset_resume = usb_serial_resume,#endif .no_dynamic_id = 1,.supports_autosuspend = 1,};
4. Modify Kernel Configuration
Step 1:
cd <your kernel directory>
Step 2:Set your environment variables, and import your board’s defconfig. The following is an example
for Raspeberrypi board
export ARCH=armexport CROSS_COMPILE=arm-none-linux-gnueabimake bcmrpi_defconfig
Step 3:
make menuconfig
Step 4:Enable CONFIG_USB_SERIAL_OPTION
[*] Device Drivers →[*] USB Support →[*] USB Serial Converter support →[*] USB driver for GSM and CDMA modems
Step 5:Configure Kernel to Support PPP
[*] Device Drivers →[*] Network device support →[*] PPP (point-to-point protocol) support
5. 编译内核
make
将编译好的内核下载到开发板。
二、模块测试
将重新编译好的内核下载到开发板之后，待系统重新启动，肉驱动添加正确，在/dev/目录下会出现如下设备节点：
/dev/ttyUSB0 /dev/ttyUSB1 /dev/ttyUSB2 /dev/ttyUSB3
EC20的AT端口是/dev/ttyUSB2，现在你可以使用UART端口工具如“minicom”或“busybox microcom”测试AT功能，结果如下：
#busybox microcom /dev/ttyUSB2ati;+csubQuectelEC20FRevision: EC20CEFDR02A09M4GSubEdition: V04OK
三、拨号
方案一
通过几个不同的配置文件，在拨号的时候选择相应的配置文件，现将配置文件列举如下：
/etc/ppp/peers/quectel-ppp
# /etc/ppp/peers/quectel-pppd# Usage:root>pppd call quectel-pppd#Modem path, like /dev/ttyUSB3,/dev/ttyACM0, depend on your module, default path is /dev/ttyUSB3/dev/ttyUSB3 115200#Insert the username and password for authentication, default user and password are testuser "test" password "test"# The chat script, customize your APN in this fileconnect 'chat -s -v -f /etc/ppp/peers/quectel-chat-connect'# The close scriptdisconnect 'chat -s -v -f /etc/ppp/peers/quectel-chat-disconnect'# Hide password in debug messageshide-password# The phone is not required to authenticatenoauth# Debug info from pppddebug# If you want to use the HSDPA link as your gatewaydefaultroute# pppd must not propose any IP address to the peernoipdefault# No ppp compressionnovjnovjccompnoccpipcp-accept-localipcp-accept-remotelocal# For sanity, keep a lock on the serial linelockmodemdumpnodetach# Hardware flow controlnocrtsctsremotename 3gpppipparam 3gpppipcp-max-failure 30# Ask the peer for up to 2 DNS server addressesusepeerdns
/etc/ppp/peers/quectel-chat-connect
# /etc/ppp/peers/quectel-chat-connectABORT "BUSY"ABORT "NO CARRIER"ABORT "NO DIALTONE"ABORT "ERROR"ABORT "NO ANSWER"TIMEOUT 30"" ATOK ATE0OK ATI;+CSUB;+CSQ;+CPIN?;+COPS?;+CGREG?;&D2# Insert the APN provided by your network operator, default apn is 3gnetOK AT+CGDCONT=1,"IP","3gnet",,0,0OK ATD*99#CONNECT
/etc/ppp/peers/quectel-chat-disconnect
# /etc/ppp/peers/quectel-chat-disconnectABORT "ERROR"ABORT "NO DIALTONE"SAY "\nSending break to the modem\n""" +++"" +++"" +++SAY "\nGoodbay\n"
编辑好这几个文件之后，便可以通过pppd进行拨号：
# pppd call quectel-ppp &
如果拨号成功会有以下信息打印出来：
[root@zx64352 peers]# pppd call quectel-ppppppd options in effect:debug # (from /etc/ppp/peers/quectel-ppp)nodetach# (from /etc/ppp/peers/quectel-ppp)dump # (from /etc/ppp/peers/quectel-ppp)noauth# (from /etc/ppp/peers/quectel-ppp)user test# (from /etc/ppp/peers/quectel-ppp)password ?????? # (from /etc/ppp/peers/quectel-ppp)remotename 3gppp# (from /etc/ppp/peers/quectel-ppp)/dev/ttyUSB3 # (from /etc/ppp/peers/quectel-ppp)115200# (from /etc/ppp/peers/quectel-ppp)lock # (from /etc/ppp/peers/quectel-ppp)connect chat -s -v -f /etc/ppp/peers/quectel-chat-connect# (from /etc/ppp/peers/quectel-ppp)disconnect chat -s -v -f /etc/ppp/peers/quectel-chat-disconnect # (from /etc/ppp/peers/quectel-ppp)nocrtscts# (from /etc/ppp/peers/quectel-ppp)modem # (from /etc/ppp/peers/quectel-ppp)hide-password # (from /etc/ppp/peers/quectel-ppp)novj # (from /etc/ppp/peers/quectel-ppp)novjccomp# (from /etc/ppp/peers/quectel-ppp)ipcp-accept-local# (from /etc/ppp/peers/quectel-ppp)ipcp-accept-remote # (from /etc/ppp/peers/quectel-ppp)ipparam 3gppp # (from /etc/ppp/peers/quectel-ppp)noipdefault # (from /etc/ppp/peers/quectel-ppp)ipcp-max-failure 30 # (from /etc/ppp/peers/quectel-ppp)defaultroute # (from /etc/ppp/peers/quectel-ppp)usepeerdns # (from /etc/ppp/peers/quectel-ppp)noccp # (from /etc/ppp/peers/quectel-ppp)abort on (BUSY)abort on (NO CARRIER)abort on (NO DIALTONE)abort on (ERROR)abort on (NO ANSWER)timeout set to 30 secondssend (AT^M)expect (OK)AT^M^MOK-- got itsend (ATE0^M)expect (OK)^MATE0^M^MOK-- got itsend (ATI;+CSUB;+CSQ;+CPIN?;+COPS?;+CGREG?;&D2^M)expect (OK)^M^MQuectel^MEC20F^MRevision: EC20CEFDR02A09M4G^M^MSubEdition: V04^M^M+CSQ: 14,99^M^M+CPIN: READY^M^M+COPS: 0^M^M+CGREG: 0,0^M^MOK-- got itsend (AT+CGDCONT=1,"IP","3gnet",,0,0^M)expect (OK)^M^MOK-- got itsend (ATD*99#^M)expect (CONNECT)^M^MCONNECT-- got itScript chat -s -v -f /etc/ppp/peers/quectel-chat-connect finished (pid 785), status = 0x0Serial connection established.using channel 1Using interface ppp0Connect: ppp0 <--> /dev/ttyUSB3sent [LCP ConfReq id=0x1 <asyncmap 0x0> <magic 0x1f2b413> <pcomp> <accomp>]rcvd [LCP ConfReq id=0x0 <asyncmap 0x0> <auth chap MD5> <magic 0xd11eadc2> <pcomp> <accomp>]sent [LCP ConfAck id=0x0 <asyncmap 0x0> <auth chap MD5> <magic 0xd11eadc2> <pcomp> <accomp>]rcvd [LCP ConfAck id=0x1 <asyncmap 0x0> <magic 0x1f2b413> <pcomp> <accomp>]rcvd [LCP DiscReq id=0x1 magic=0xd11eadc2]rcvd [CHAP Challenge id=0x1 <40aedf97298706e7675d614c0cea9175>, name = "UMTS_CHAP_SRVR"]sent [CHAP Response id=0x1 <1bf312e7aa43615e474c49c28fbbaca5>, name = "test"]rcvd [CHAP Success id=0x1 ""]CHAP authentication succeededCHAP authentication succeededsent [IPCP ConfReq id=0x1 <addr 0.0.0.0> <ms-dns1 0.0.0.0> <ms-dns2 0.0.0.0>]rcvd [IPCP ConfReq id=0x0]sent [IPCP ConfNak id=0x0 <addr 0.0.0.0>]rcvd [IPCP ConfNak id=0x1 <addr 10.35.149.45> <ms-dns1 218.4.4.4> <ms-dns2 218.2.2.2>]sent [IPCP ConfReq id=0x2 <addr 10.35.149.45> <ms-dns1 218.4.4.4> <ms-dns2 218.2.2.2>]rcvd [IPCP ConfReq id=0x1]sent [IPCP ConfAck id=0x1]rcvd [IPCP ConfAck id=0x2 <addr 10.35.149.45> <ms-dns1 218.4.4.4> <ms-dns2 218.2.2.2>]Could not determine remote IP address: defaulting to 10.64.64.64local IP address 10.35.149.45remote IP address 10.64.64.64primary DNS address 218.4.4.4secondary DNS address 218.2.2.2
此时也会在/etc/ppp/目录下生成resolv.conf文件，存放pppd拨号获取到的DNS，可以将改文件拷贝到/etc/目录下，这样便可以进行DNS解析了，至此开发板也可以通过EC20模块连接到互联网了。
方案二
方案一中的端口号、APN、用户名、密码等都是直接写在配置文件中，这样如果要更换这些内容的话要频繁修改配置文件，既消耗时间，又不太方便。所以便将几个配置文件融合到一个脚本中，并且可以通过传递参数那样修改需要修改的内容，脚本内容如下：
/etc/ppp/peers/quectel-pppd.sh
#!/bin/sh#quectel-pppd devname apn user passwordecho "quectel-pppd options in effect:"QL_DEVNAME=/dev/ttyUSB3QL_APN=3gnetQL_USER=userQL_PASSWORD=passwdif [ $# -ge 1 ]; thenQL_DEVNAME=$1 echo "devname $QL_DEVNAME # (from command line)"elseecho "devname $QL_DEVNAME # (default)"fiif [ $# -ge 2 ]; thenQL_APN=$2 echo "apn $QL_APN # (from command line)"elseecho "apn $QL_APN # (default)"fiif [ $# -ge 3 ]; thenQL_USER=$3 echo "user$QL_USER # (from command line)"elseecho "user$QL_USER # (default)"fiif [ $# -ge 4 ]; thenQL_PASSWORD=$4 echo "password $QL_PASSWORD # (from command line)"elseecho "password $QL_PASSWORD # (default)"fiCONNECT="'chat -s -v ABORT BUSY ABORT \"NO CARRIER\" ABORT \"NO DIALTONE\" ABORT ERROR ABORT \"NO ANSWER\" TIMEOUT 30 \\"\" AT OK ATE0 OK ATI\;+CSUB\;+CSQ\;+CPIN?\;+COPS?\;+CGREG?\;\&D2 \OK AT+CGDCONT=1,\\\"IP\\\",\\\"$QL_APN\\\",,0,0 OK ATD*99# CONNECT'"pppd $QL_DEVNAME 115200 user "$QL_USER" password "$QL_PASSWORD" \connect "'$CONNECT'" \disconnect 'chat -s -v ABORT ERROR ABORT "NO DIALTONE" SAY "\nSending break to the modem\n" "" +++ "" +++ "" +++ SAY "\nGood bay\n"' \noauth debug defaultroute noipdefault novj novjccomp noccp ipcp-accept-local ipcp-accept-remote ipcp-max-configure 30 local lock modem dump nodetach nocrtscts usepeerdns
拨号
/etc/ppp/peers/quectel-pppd.sh &
输出信息跟方案一输出一样，同样会生成/etc/ppp/resolv.conf文件。
注：在进行拨号之前一定要确保没有默认网关，如果已经设置了其他网卡的默认网关了，则4G模块没法正常上网，需要删除原来的默认网关，现以网卡eth0为例：
route del defaultroute del -host 255.255.255.255 dev eth0
