一、USB Serial Driver 安装
当设备连接4G模块后，查看 /dev 下是否有以下设备文件：
ttyUSB0/ttyUSB1/ttyUSB2…
如果没有，则需要按照下列步骤集成USB串行驱动程序（以下操作均需要在内核根目录下进行，因此在操作前要安装对应版本的内核源码）:
1.1 添加 VID 和 PID
为了识别模块，客户应该添加模块VID和PID信息，如下所示：
File: [KERNEL]/drivers/usb/serial/option.c
static const struct usb_device_id option_ids[] = {#if 1 //Added by Quectel{USB_DEVICE(0x05C6, 0x9090) }, /* Quectel UC15 */ {USB_DEVICE(0x05C6, 0x9003) }, /* Quectel UC20 */ {USB_DEVICE(0x2C7C, 0x0125) }, /* Quectel EC25 */{USB_DEVICE(0x2C7C, 0x0121) }, /* Quectel EC21 */ {USB_DEVICE(0x05C6, 0x9215) }, /* Quectel EC20 */ {USB_DEVICE(0x2C7C, 0x0191) }, /* Quectel EG91 */ {USB_DEVICE(0x2C7C, 0x0195) }, /* Quectel EG95 */{USB_DEVICE(0x2C7C, 0x0306) }, /* Quectel EG06/EP06/EM06 */{USB_DEVICE(0x2C7C, 0x0296) }, /* Quectel BG96 */{USB_DEVICE(0x2C7C, 0x0435) }, /* Quectel AG35 */#endif
对于EC20模块，如果内核源文件中存在以下文件和语句，请删除它们，因为它们会与EC20的USB驱动程序冲突。
File: [KERNEL]/drivers/usb/serial/qcserial.c
{USB_DEVICE(0x05c6, 0x9215)}, /* Acer Gobi 2000 Modem device (VP413) */
File: [KERNEL]/drivers/net/usb/qmi_wwan.c
{QMI_GOBI_DEVICE(0x05c6, 0x9215)}, /* Acer Gobi 2000 Modem device (VP413) */
1.2 添加零分组机制
根据USB协议的要求，客户需要在大量传输过程中添加用于处理零数据包的机制。
对于高于2.6.34的Linux内核版本：
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 *)) {……usb_fill_bulk_urb(urb, serial->dev, usb_sndbulkpipe(serial->dev, endpoint) | dir, buf, len, callback, ctx); #if 1 //Added by Quectel for zero packetif (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; } #endifreturn urb; }
对于Linux内核版本低于2.6.35：
File: [KERNEL]/drivers/usb/serial/option.c
/* Helper functions used by option_setup_urbs */ static struct urb *option_setup_urb(struct usb_serial *serial, int endpoint,int dir, void *ctx, char *buf, int len, void (*callback)(struct urb *)) {……usb_fill_bulk_urb(urb, serial->dev, usb_sndbulkpipe(serial->dev, endpoint) | dir, buf, len, callback, ctx); #if 1 //Added by Quectel for zero packetif (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; #endifreturn urb; }
1.3 添加重置恢复
一些USB主机控制器/USB集线器将在MCU进入暂停/睡眠模式时损失或重置，并且在MCU从暂停/睡眠模式下退出后，它们无法恢复USB设备。请添加以下语句以启用重置恢复过程。
对于Linux内核版本高于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 };
对于Linux内核版本低于3.5：
File: [KERNEL]/drivers/usb/serial/ usb-serial.c
/* Driver structure we register with the USB core */ 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 //Added by Quectel.reset_resume = usb_serial_resume, #endif.no_dynamic_id = 1, .supports_autosuspend = 1, };
1.4 放大散装网址
对于低于2.6.29的Linux内核版本，大量URB需要放大以获得更快的上行链路速度。
File: [KERNEL]/drivers/usb/serial/option.c
#define N_IN_URB 4 #define N_OUT_URB 4 //Quectel 1#define IN_BUFLEN 4096 #define OUT_BUFLEN 4096 //Quectel 128
1.5 使用 GobiNet 或 QMI WWAN
如果要求使用Gobinet或QMI WWAN，请添加以下语句以防止这些模块的接口4作为USB串行设备。
对于Linux内核版本高于2.6.30：
File: [KERNEL]/drivers/usb/serial/option.c
static int option_probe(struct usb_serial *serial, const struct usb_device_id *id) {struct usb_wwan_intf_private *data; ……#if 1 //Added by Quectel//Quectel UC20's interface 4 can be used as USB network device if (serial->dev->descriptor.idVendor == cpu_to_le16(0x05C6) &&serial->dev->descriptor.idProduct == cpu_to_le16(0x9003) && serial->interface->cur_altsetting->desc.bInterfaceNumber >= 4) return -ENODEV; //Quectel EC20's interface 4 can be used as USB network device if (serial->dev->descriptor.idVendor == cpu_to_le16(0x05C6) && serial->dev->descriptor.idProduct == cpu_to_le16(0x9215) && serial->interface->cur_altsetting->desc.bInterfaceNumber >= 4) return -ENODEV; //Quectel EC25&EC21&EG91&EG95&EG06&EP06&EM06&BG96/AG35's interface 4 can be used as USB network device if (serial->dev->descriptor.idVendor == cpu_to_le16(0x2C7C) && serial->interface->cur_altsetting->desc.bInterfaceNumber >= 4) return -ENODEV; #endif/* Store device id so we can use it during attach. */ usb_set_serial_data(serial, (void *)id); return 0; }
对于Linux内核版本低于2.6.31：
File: [KERNEL]/drivers/usb/serial/option.c
static int option_startup(struct usb_serial *serial) {……dbg("%s", __func__); #if 1 //Added by Quectel//Quectel UC20's interface 4 can be used as USB network device if (serial->dev->descriptor.idVendor == cpu_to_le16(0x05C6) && serial->dev->descriptor.idProduct == cpu_to_le16(0x9003) && serial->interface->cur_altsetting->desc.bInterfaceNumber >= 4) return -ENODEV; //Quectel EC20's interface 4 can be used as USB network device if (serial->dev->descriptor.idVendor == cpu_to_le16(0x05C6) && serial->dev->descriptor.idProduct == cpu_to_le16(0x9215) && serial->interface->cur_altsetting->desc.bInterfaceNumber >= 4) return -ENODEV; //Quectel EC25&EC21&EG91&EG95&EG06&EP06&EM06&BG96/AG35's interface 4 can be used as USB network device if (serial->dev->descriptor.idVendor == cpu_to_le16(0x2C7C) && serial->interface->cur_altsetting->desc.bInterfaceNumber >= 4) return -ENODEV; #endif ……}
1.6 修改内核配置
内核配置中有几个强制性选定项目，请按照以下步骤配置内核：
步骤1：进入到内核根目录。
cd < your kernel directory >
步骤2：设置环境变量和导入板的defconfig。以下是RaspeBerry Pi板的示例。
export ARCH=arm
export CROSS_COMPILE=arm-none-linux-gnueabi-
make bcmrpi_defconfig
对于X86架构的系统，我的默认的defconfig文件为x86_64_defconfig，只需要在内核根目录下make x86_64_defconfig
步骤3：编译内核。
make menuconfig
步骤4：启用CONFIG_USB_SERIAL_OPTION
[*] Device Drivers →[*] USB Support → [*] USB Serial Converter support →[*] USB driver for GSM and CDMA modems
1.7 作为内核模块构建并加载驱动程序
请按照以下步骤将驱动程序作为内核模块构建。
步骤1：进入到内核根目录。
cd < your kernel directory >
步骤2：构建驱动程序。
sudo make -C /lib/modules/`uname -r`/build M=`pwd`/drivers/usb/serial obj-m=option.o modules
sudo make -C /lib/modules/`uname -r`/build M=`pwd`/drivers/usb/serial obj-m=usb_wwan.o modules
sudo make -C /lib/modules/`uname -r`/build M=`pwd`/drivers/usb/serial obj-m=qcserial.o modules
步骤3：加载驱动程序并重新启动。
sudo cp drivers/usb/serial/option.ko /lib/modules/`uname -r`/kernel/drivers/usb/serial
sudo cp drivers/usb/serial/usb_wwan.ko /lib/modules/`uname -r`/kernel/drivers/usb/serial
sudo cp drivers/usb/serial/qcserial.ko /lib/modules/`uname -r`/kernel/drivers/usb/serial
sudo depmod
sudo reboot
二、配置内核以支持PPP
首先检测 /dev 下面是否有 ppp 设备，没有的话请按照以下步骤配置内核以支持PPP。
步骤1：进入到内核根目录。
cd < your kernel directory >
步骤2：设置环境变量和导入板的defconfig。下面显示了一个例子。
export ARCH=arm
export CROSS_COMPILE=arm-none-linux-gnueabi-
make bcmrpi_defconfig
对于X86架构的系统，我的默认的defconfig文件为x86_64_defconfig，只需要在内核根目录下make x86_64_defconfig
步骤3：编译内核。
make menuconfig
步骤4：启用CONFIG_PPP_ASYNC CONFIG_PPP_SYNC_TTY CONFIG_PPP_DEFLATE
[*] Device Drivers → [*] Network device support → [*] PPP (point-to-point protocol) support
内核启动后在 /dev 下生成 ppp 设备节点
三、测试PPP拨号上网
下载ppp服务：/download.html
解压：tar -xzvf ppp-2.4.4.tar.gz
cd ppp-2.4.4
./configure
make && make install
实现ppp拨号上网：
查看是否有名为/etc/ppp/ip-up的ppp脚本文件，用于设置DNS（域名系统）。如果没有这样的文件，请使用 Quectel 提供的linux-ppp-scripts\ip-up。
关于 linux-ppp-scripts_V1.2.zip 请自行到网上下载。
解压：unzip linux-ppp-scripts_V1.2.zip
将linux-ppp-scripts里面的quectel-ppp，quectel-chat-connect，quectel-chat-disconnect三个脚本复制到/etc/ppp/peers目录下
根据不同的模块，客户可能需要进行一些更改。有关更多信息，请参阅linux-ppp-scripts\readme。
然后通过以下命令开始设置PPP呼叫：
pppd call quectel-ppp &
拨号过程如下所示（EC20的示例）:
# pppd 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 10 # (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 seconds send (AT^M) expect (OK) ^MOK-- got it send (ATE0^M) expect (OK) ^M^MOK-- got itsend (ATI;+CSUB;+CSQ;+CPIN?;+COPS?;+CGREG?;&D2^M) expect (OK) ^M^MQuectel^M EC20^M Revision: EC20CQAR02A03E2G_BETA0914^M ^MSubEdition: V01^M ^M+CSQ: 23,99^M ^M+CPIN: READY^M ^M+COPS: 0,0,"CHN-CT",7^M ^M+CGREG: 2,1,"FFFE","6916934",7^M ^MOK-- got it send (AT+CGDCONT=1,"IP","3gnet",,0,0^M) expect (OK) ^M^MOK-- got it send (ATD*99#^M) expect (CONNECT) ^M^MCONNECT -- got it Script chat -s -v -f /etc/ppp/peers/quectel-chat-connect finished (pid 3017), status = 0x0 Serial connection established. using channel 3 Using interface ppp0 Connect: ppp0 <--> /dev/ttyUSB3 sent [LCP ConfReq id=0x1 <asyncmap 0x0> <magic 0xf2b7d6ee> <pcomp> <accomp>] rcvd [LCP ConfReq id=0x4 <asyncmap 0x0> <auth chap MD5> <magic 0x45c0e381> <pcomp> <accomp>] sent [LCP ConfAck id=0x4 <asyncmap 0x0> <auth chap MD5> <magic 0x45c0e381> <pcomp> <accomp>] rcvd [LCP ConfAck id=0x1 <asyncmap 0x0> <magic 0xf2b7d6ee> <pcomp> <accomp>] rcvd [LCP DiscReq id=0x5 magic=0x45c0e381] rcvd [CHAP Challenge id=0x1 <f8d54e0fa294c100101805a512176ff1>, name = "UMTS_CHAP_SRVR"] sent [CHAP Response id=0x1 <e8ad86182138523599fb54a172da7154>, name = "test"] rcvd [CHAP Success id=0x1 ""] CHAP authentication succeeded CHAP authentication succeeded sent [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=0x4] sent [IPCP ConfNak id=0x4 <addr 0.0.0.0>] rcvd [IPCP ConfNak id=0x1 <addr 100.65.245.137> <ms-dns1 61.132.163.68> <ms-dns2 202.102.213.68>] sent [IPCP ConfReq id=0x2 <addr 100.65.245.137> <ms-dns1 61.132.163.68> <ms-dns2 202.102.213.68>] rcvd [IPCP ConfReq id=0x5] sent [IPCP ConfAck id=0x5] rcvd [IPCP ConfAck id=0x2 <addr 100.65.245.137> <ms-dns1 61.132.163.68> <ms-dns2 202.102.213.68>] Could not determine remote IP address: defaulting to 10.64.64.64 local IP address 100.65.245.137 remote IP address 10.64.64.64 primary DNS address 61.132.163.68 secondary DNS address 202.102.213.68 Script /etc/ppp/ip-up started (pid 3020) Script /etc/ppp/ip-up finished (pid 3020), status = 0x0
现在PPP呼叫设置成功。通过以下方式查看：
ifconfig ppp0 ppp0 Link encap:Point-to-Point Protocol inet addr:100.65.245.137 P-t-P:10.64.64.64 Mask:255.255.255.255 UP POINTOPOINT RUNNING NOARP MULTICAST MTU:1500 Metric:1 RX packets:15 errors:0 dropped:0 overruns:0 frame:0 TX packets:19 errors:0 dropped:0 overruns:0 carrier:0 collisions:0 txqueuelen:3 RX bytes:1057 (1.0 KiB) TX bytes:1228 (1.1 KiB)
cat /etc/resolv.conf nameserver 61.132.163.68 nameserver 202.102.213.68
route -n Kernel IP routing table DestinationGatewayGenmask Flags Metric Ref Use Iface 10.64.64.64 0.0.0.0 255.255.255.255 UH 0 0 0 ppp00.0.0.0 0.0.0.0 0.0.0.0 U 0 0 0 ppp0
ping PING www. (115.239.211.112) 56(84) bytes of data. 64 bytes from 115.239.211.112: icmp_seq=1 ttl=54 time=46.4 ms
关闭PPP呼叫：
pkill -f pppd
参考文献：
《Quectel_WCDMA<E_Linux_USB_Driver_User_Guide_V1.8.pdf》
