参考了不少教程，也做了不少尝试，最后记录下整个过程以便自己和坛友们参考

我所用的4G模块是Quectel EC20 R2.0，对于这个型号以下的操作前半部分修改USB Serial驱动应该是不需要的，但是我也都修改了并且记录下来，对于其他品牌型号的模块应该是原理相通的

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2020-5-31 11:04 上传

修改内核增加USB Serial驱动支持

1.增加PID&VID，教程中所用内核4.4.79尚没有支持，我用的4.19.122已经支持，而且两者之间的定义方式稍有不同

教程里需要添加的代码为

build_dir/target-mips_24kc_musl/linux-ar71xx_generic/linux-4.4.79/drivers/usb/serial/option.c

【注】只添加#if 1 到 #endif的内容

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

可以看到是在结构体usb_device_id option_ids[]里添加了移远各型号的PID和VID

而新内核的此结构体是通过在前面define然后后面通过VENDOR_ID和PRODUCT来定义

#define QUECTEL_VENDOR_ID                                0x2c7c

/* These Quectel products use Quectel's vendor ID */

#define QUECTEL_PRODUCT_EC21                        0x0121

#define QUECTEL_PRODUCT_EC25                        0x0125

#define QUECTEL_PRODUCT_BG96                        0x0296

#define QUECTEL_PRODUCT_EP06                        0x0306

#define QUECTEL_PRODUCT_EM12                        0x0512

#define QUECTEL_PRODUCT_RM500Q                        0x0800

后面则是

{ USB_DEVICE(QUECTEL_VENDOR_ID, QUECTEL_PRODUCT_EC25), .driver_info = RSVD(4) },

总之就是此处不需要额外修改了

2.添加零包处理

文件位于build_dir/target-mips_24kc_musl/linux-ar71xx_generic/linux-4.4.79/drivers/usb/serial/usb_wwan.c

添加在函数urb中

static struct urb *usb_wwan_setup_urb(struct usb_serial_port *port,

int endpoint,

int dir, void *ctx, char *buf, int len,

void (*callback) (struct urb *))

{

struct usb_serial *serial = port->serial;

struct usb_wwan_intf_private *intfdata = usb_get_serial_data(serial);

struct urb *urb;

urb = usb_alloc_urb(0, GFP_KERNEL);        /* No ISO */

if (!urb)

return NULL;

usb_fill_bulk_urb(urb, serial->dev,

usb_sndbulkpipe(serial->dev, endpoint) | dir,

buf, len, callback, ctx);

if (intfdata->use_zlp && dir == USB_DIR_OUT)

urb->transfer_flags |= URB_ZERO_PACKET;

#if 1 //Added by Quectelfor Zero Packet

if (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;

if (desc->idVendor == cpu_to_le16(0x1286) && desc->idProduct == cpu_to_le16(0x4e3d))

{

urb->transfer_flags |= URB_ZERO_PACKET;

}

}

#endif

return urb;

}

3.增加休眠后唤醒接口

文件位于build_dir/target-mips_24kc_musl/linux-ar71xx_generic/linux-4.4.79/drivers/usb/serial/option.c

添加在option_1port_device结构体中

static struct usb_serial_driver option_1port_device = {

.driver = {

.owner =        THIS_MODULE,

.name =                "option1",

},

.description       = "GSM modem (1-port)",

.id_table          = option_ids,

.num_ports         = 1,

.probe             = option_probe,

.open              = usb_wwan_open,

.close             = usb_wwan_close,

.dtr_rts           = usb_wwan_dtr_rts,

.write             = usb_wwan_write,

.write_room        = usb_wwan_write_room,

.chars_in_buffer   = usb_wwan_chars_in_buffer,

.tiocmget          = usb_wwan_tiocmget,

.tiocmset          = usb_wwan_tiocmset,

.ioctl             = usb_wwan_ioctl,

.attach            = option_attach,

.release           = option_release,

.port_probe        = usb_wwan_port_probe,

.port_remove           = usb_wwan_port_remove,

.read_int_callback = option_instat_callback,

#ifdef CONFIG_PM

.suspend           = usb_wwan_suspend,

.resume            = usb_wwan_resume,

#if 1 //Added by Quectel

.reset_resume      = usb_wwan_resume,

#endif

#endif

};

4.使用 GobiNet or QMI WWAN

如果使用ucxx/ec2x/egxx/EP06/EM06/BG96/AG35，并要求GobiNet或QMI WWAN，请添加以下语句，以防止这些模块接口4被用作USB串行设备

文件位于build_dir/target-mips_24kc_musl/linux-ar71xx_generic/linux-4.4.79/drivers/usb/serial/option.c

添加在函数option_probe中

static int option_probe(struct usb_serial *serial,

const struct usb_device_id *id)

{

struct usb_interface_descriptor *iface_desc =

&serial->interface->cur_altsetting->desc;

unsigned long device_flags = id->driver_info;

/* Never bind to the CD-Rom emulation interface        */

if (iface_desc->bInterfaceClass == USB_CLASS_MASS_STORAGE)

return -ENODEV;

/*

* Don't bind reserved interfaces (like network ones) which often have

* the same class/subclass/protocol as the serial interfaces.  Look at

* the Windows driver .INF files for reserved interface numbers.

*/

if (device_flags & RSVD(iface_desc->bInterfaceNumber))

return -ENODEV;

/*

* Allow matching on bNumEndpoints for devices whose interface numbers

* can change (e.g. Quectel EP06).

*/

if (device_flags & NUMEP2 && iface_desc->bNumEndpoints != 2)

return -ENODEV;

#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 the device flags so we can use them during attach. */

usb_set_serial_data(serial, (void *)device_flags);

return 0;

}

以下部分则是必须的了，不然即便设备和接口都能正常识别，但是却没法获取ip，此处参考https://www.right.com.cn/forum/thread-480555-1-1.html

修改内核增加QMI WWAN驱动支持

1.增加VID和PID

文件位于build_dir/target-mips_24kc_musl/linux-ar71xx_generic/linux-4.4.79/drivers/net/usb/qmi_wwan.c

在结构体usb_device_id products[]中

static const struct usb_device_id products[] = {

#if 1 //Added by Quectel

#ifndef QMI_FIXED_INTF

/* map QMI/wwan function by a fixed interface number */

#define QMI_FIXED_INTF(vend, prod, num) \

.match_flags = USB_DEVICE_ID_MATCH_DEVICE |

USB_DEVICE_ID_MATCH_INT_INFO, \

.idVendor = vend, \

.idProduct = prod, \

.bInterfaceClass = 0xff, \

.bInterfaceSubClass = 0xff, \

.bInterfaceProtocol = 0xff, \

.driver_info = (unsigned long)&qmi_wwan_force_int##num,

#endif

{ QMI_FIXED_INTF(0x05C6, 0x9003, 4) }, /* Quectel UC20 */

{ QMI_FIXED_INTF(0x2C7C, 0x0125, 4) }, /* Quectel EC25 */

{ QMI_FIXED_INTF(0x2C7C, 0x0121, 4) }, /* Quectel EC21 */

{ QMI_FIXED_INTF(0x05C6, 0x9215, 4) }, /* Quectel EC20 */

{ QMI_FIXED_INTF(0x2C7C, 0x0191, 4) }, /* Quectel EG91 */

{ QMI_FIXED_INTF(0x2C7C, 0x0195, 4) }, /* Quectel EG95 */

{ QMI_FIXED_INTF(0x2C7C, 0x0306, 4) }, /* Quectel EG06/EP06/EM06 */

{ QMI_FIXED_INTF(0x2C7C, 0x0296, 4) }, /* Quectel BG96 */

{ QMI_FIXED_INTF(0x2C7C, 0x0435, 4) }, /* Quectel AG35 */

#endif

但是我注意到源文件里有

#define QMI_MATCH_FF_FF_FF(vend, prod) \

USB_DEVICE_AND_INTERFACE_INFO(vend, prod, USB_CLASS_VENDOR_SPEC, \

USB_SUBCLASS_VENDOR_SPEC, 0xff), \

.driver_info = (unsigned long)&qmi_wwan_info_quirk_dtr

...

...

{QMI_MATCH_FF_FF_FF(0x2c7c, 0x0125)},        /* Quectel EC25, EC20 R2.0  Mini PCIe */

{QMI_MATCH_FF_FF_FF(0x2c7c, 0x0306)},        /* Quectel EP06/EG06/EM06 */

{QMI_MATCH_FF_FF_FF(0x2c7c, 0x0512)},        /* Quectel EG12/EM12 */

{QMI_MATCH_FF_FF_FF(0x2c7c, 0x0800)},        /* Quectel RM500Q-GL */

不知道此处应该怎么理解

2.增加对Raw IP Mode的支持

文件位于build_dir/target-mips_24kc_musl/linux-ar71xx_generic/linux-4.4.79/drivers/net/usb/qmi_wwan.c

增加一个函数

struct sk_buff *qmi_wwan_tx_fixup(struct usbnet *dev, struct sk_buff *skb, gfp_t flags) {

if (dev->udev->descriptor.idVendor != cpu_to_le16(0x2C7C))

return skb;

// Skip Ethernet header from message

if (skb_pull(skb, ETH_HLEN)) {

return skb;

} else {

dev_err(&dev->intf->dev, "Packet Dropped ");

}

// Filter the packet out, release it

dev_kfree_skb_any(skb);

return NULL;

};

本来教程还要添加一部分LINUX_VERSION_CODE < KERNEL_VERSION( 3,9,1 )也就是处理内核版本低于3.9.1的，因为已知肯定是高于这个版本了，我就没有添加了

下来是修改qmi_wwan_bind函数

static int qmi_wwan_bind(struct usbnet *dev, struct usb_interface *intf)

{

int status = -1;

u8 *buf = intf->cur_altsetting->extra;

int len = intf->cur_altsetting->extralen;

...

...

/* make MAC addr easily distinguishable from an IP header */

if (possibly_iphdr(dev->net->dev_addr)) {

dev->net->dev_addr[0] |= 0x02;        /* set local assignment bit */

dev->net->dev_addr[0] &= 0xbf;        /* clear "IP" bit */

}

dev->net->netdev_ops = &qmi_wwan_netdev_ops;

dev->net->sysfs_groups[0] = &qmi_wwan_sysfs_attr_group;

#if 1 //Added by Quectel

if (dev->udev->descriptor.idVendor == cpu_to_le16(0x2C7C)) {

dev_info(&intf->dev, "Quectel EC25&EC21&EG91&EG95&EG06&EP06&EM06&BG96&AG35 work on RawIP mode\n");

dev->net->flags |= IFF_NOARP;

usb_control_msg(

interface_to_usbdev(intf),

usb_sndctrlpipe(interface_to_usbdev(intf), 0),

0x22, //USB_CDC_REQ_SET_CONTROL_LINE_STATE

0x21, //USB_DIR_OUT | USB_TYPE_CLASS | USB_RECIP_INTERFACE

1, //active CDC DTR

intf->cur_altsetting->desc.bInterfaceNumber,

NULL, 0, 100);

}

#endif

err:

return status;

}

教程里还有一个要修改的函数qmi_wwan_bind_shared，但是在此处不存在，所以不修改

然后是两个结构体qmi_wwan_info和qmi_wwan_info_quirk_dtr里需要添加

static const struct driver_info        qmi_wwan_info = {

.description        = "WWAN/QMI device",

.flags                = FLAG_WWAN | FLAG_SEND_ZLP,

.bind                = qmi_wwan_bind,

.unbind                = qmi_wwan_unbind,

.manage_power        = qmi_wwan_manage_power,

.rx_fixup       = qmi_wwan_rx_fixup,

#if 1 //Added by Quectel

.tx_fixup       = qmi_wwan_tx_fixup,

#endif

};

static const struct driver_info        qmi_wwan_info_quirk_dtr = {

.description        = "WWAN/QMI device",

.flags                = FLAG_WWAN | FLAG_SEND_ZLP,

.bind                = qmi_wwan_bind,

.unbind                = qmi_wwan_unbind,

.manage_power        = qmi_wwan_manage_power,

.rx_fixup       = qmi_wwan_rx_fixup,

#if 1 //Added by Quectel

.tx_fixup       = qmi_wwan_tx_fixup,

#endif

.data           = QMI_WWAN_QUIRK_DTR,

};

编译设置

内核

Device Drivers ->

USB Support ->

USB Serial Converter support ->

USB driver for GSM and CMDA modems

Device Drivers →

-*- Network device support →

USB Network Adapters →

{*} Multi-purpose USB Networking Framework

QMI WWAN driver for Qualcomm MSM based 3G and LTE modems

常规

Kernel modules >>

USB Support >>

Kmod -usb-core

-*-   Kmod -usb-net

-*-   Kmod-usb-net-cdc-ether

Kmod-usb-net-cdc-mbim

-*-   Kmod-usb-net-cdc-ncm

Kmod-usb-net-cdc-subset

Kmod-usb-net-qmi-wwan

Kmod-usb-ohci

Kmod-usb-serial

Kmod-usb-serial-option

Kmod-usb-uhci

Kmod-usb2

NetWork   >>

wwan

chat

ppp

umbim

Utilities

quectel_cm

usb-modeswitch

Luci

1. Collections

luci

3. Applications

luci-app-multiwan (optional to support multiple 3g dongles)

luci-app-qos (optional to provide QOS support)

6. Protocols

luci-proto-3g

-*-   luci-proto-ppp

luci-proto-qmi

其中quectel_cm也是来自https://download.csdn.net/download/jianzhizuo/10749215因为Quectel对于资料方面的管控比较严格，这方面我就不私自放出了，不过我查了github上有哈哈哈

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2020-5-31 11:20 上传

编译好刷入后，在ssh执行quectel_cm &就会开始拨号，并且

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2020-5-31 11:21 上传

拨号成功后ifconfig会看到wwan0这个接口已经有了ip

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2020-5-31 11:22 上传

然后开始ping baidu.com也有结果了

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2020-5-31 11:23 上传

到了这时候，路由器自身已经可以上网了，但是还没能把网络转发给LAN，需要额外创建一个接口，叫什么无所谓，协议选DHCP，接口选wwan0，防火墙选在wan就可以了

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2020-5-31 11:20 上传

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2020-5-31 11:24 上传

其他相关内容，也是在学习过程中发现的：

采用的模块型号为移远EC20 R2.0等同于EC25，两者PID和VID一致，所以在lsusb时识别为EC25

插上后/dev会出现五个设备，分别是cdc-wdm0，ttyUSB0，ttyUSB1，ttyUSB2，ttyUSB3

其中cdc-wdm0是进行qmi拨号的设备

ttyUSB0是DM接口

ttyUSB1是GPS NMEA信息输出接口

ttyUSB2是AT指令的接口

ttyUSB3是建立ppp连接或者AT指令的接口

因为ttyUSB2是用来交互AT指令的，所以可以通过cat /dev/ttyUSB2 & 指令来保持这个接口的输出反馈，然后输入AT指令来控制模块

echo -e "AT+QCCID\r\n" >/dev/ttyUSB2    //查询SIM卡

echo -e "AT+CFUN=1,1\r\n" >/dev/ttyUSB2   //重启模块

echo -e "AT+QSIMDET=1\r\n" >/dev/ttyUSB2   //开启SIM卡热插拔状态报告

echo -e "AT+QSIMDET=1,1\r\n" >/dev/ttyUSB2  //开启SIM卡检测功能

echo -e "AT+CSQ\r\n" >/dev/ttyUSB2  //查询信号强度

echo -e "AT+QNWINFO\r\n" >/dev/ttyUSB2 //查询网络状态

echo -e "AT+CGMM\r\n" >/dev/ttyUSB2   //输出模块型号

echo -e "AT+CGMI\r\n" >/dev/ttyUSB2   //输出厂商

echo -e "AT+QCFG=\"NWSCANMODE\",3,1\r\n" >/dev/ttyUSB2 //设置4G LTE only

echo -e "AT+QCFG=\"NWSCANMODE\",2,1\r\n" >/dev/ttyUSB2 //设置3G WCDMA only

echo -e "AT+QCFG=\"NWSCANMODE\",1,1\r\n" >/dev/ttyUSB2 //设置2G GSM only

echo -e "AT+QCFG=\"NWSCANMODE\",0,1\r\n" >/dev/ttyUSB2 //设置自动搜索网络