第二篇 4G模块-USB串口驱动测试

一、编译内核

         在linux内核里边修改了对华为ME909S-821的支持，使用make uImage编译，然后下载到开发板上：上电开机，在系统启动过程会打印相关usb串口驱动的信息，但是，我们也可以使用dmesg随时查看，相关信息如下：

usb 1-1: new full-speed USB device number 2 using s3c2410-ohcicdc_ether 1-1:2.0: usb0: register 'cdc_ether' at usb-s3c24xx-1, CDC Ethernet Device, 02:1e:10:1f:00:00option 1-1:2.2: GSM modem (1-port) converter detectedusb 1-1: GSM modem (1-port) converter now attached to ttyUSB0option 1-1:2.3: GSM modem (1-port) converter detectedusb 1-1: GSM modem (1-port) converter now attached to ttyUSB1option 1-1:2.4: GSM modem (1-port) converter detectedusb 1-1: GSM modem (1-port) converter now attached to ttyUSB2option 1-1:2.5: GSM modem (1-port) converter detectedusb 1-1: GSM modem (1-port) converter now attached to ttyUSB3option 1-1:2.6: GSM modem (1-port) converter detectedusb 1-1: GSM modem (1-port) converter now attached to ttyUSB4option: option_instat_callback: error -2

最后出现错误： option_instat_callback error -2，尽管这个错误，目前还无法判断具体原因，开始测试在嵌入式开发板上打电话的功能（也就这个功能尤为吸引我）。

在这里我们要使用一个软件在ubuntu上，查看这个4G模块的信息，比如配置描述符、接口描述符、还有端点描述符等等，拥有这种功能的USB软件肯定有，幸运的是在内核大牛的网站看到这个usbview软件，下载网址：点击打开链接（感谢Greg K-H大牛）

 下载代码，解压，可参考INSTALL文件编译安装usbview软件。

最后查看这个4G模块的信息如下：

Config Number: 1Number of Interfaces: 6Attributes: a0MaxPower Needed:   2mAInterface Number: 0Name: Alternate Number: 0Class: ff(vend.) Sub Class: 06Protocol: 10Number of Endpoints: 3Endpoint Address: 82Direction: inAttribute: 3Type: Int.Max Packet Size: 10Interval: 32msEndpoint Address: 81Direction: inAttribute: 2Type: BulkMax Packet Size: 512Interval: 0msEndpoint Address: 01Direction: outAttribute: 2Type: BulkMax Packet Size: 512Interval: 0msInterface Number: 1Name: Alternate Number: 0Class: ff(vend.) Sub Class: 06Protocol: 13Number of Endpoints: 2Endpoint Address: 83Direction: inAttribute: 2Type: BulkMax Packet Size: 512Interval: 0msEndpoint Address: 02Direction: outAttribute: 2Type: BulkMax Packet Size: 512Interval: 0msInterface Number: 2Name: Alternate Number: 0Class: ff(vend.) Sub Class: 06Protocol: 12Number of Endpoints: 2Endpoint Address: 84Direction: inAttribute: 2Type: BulkMax Packet Size: 512Interval: 0msEndpoint Address: 03Direction: outAttribute: 2Type: BulkMax Packet Size: 512Interval: 0msInterface Number: 3Name: Alternate Number: 0Class: ff(vend.) Sub Class: 06Protocol: 16Number of Endpoints: 1Endpoint Address: 86Direction: inAttribute: 3Type: Int.Max Packet Size: 16Interval: 2msInterface Number: 3Name: Alternate Number: 1Class: ff(vend.) Sub Class: 06Protocol: 16Number of Endpoints: 3Endpoint Address: 86Direction: inAttribute: 3Type: Int.Max Packet Size: 16Interval: 2msEndpoint Address: 85Direction: inAttribute: 2Type: BulkMax Packet Size: 512Interval: 0msEndpoint Address: 04Direction: outAttribute: 2Type: BulkMax Packet Size: 512Interval: 0msInterface Number: 4Name: Alternate Number: 0Class: ff(vend.) Sub Class: 06Protocol: 06Number of Endpoints: 2Endpoint Address: 87Direction: inAttribute: 2Type: BulkMax Packet Size: 512Interval: 0msEndpoint Address: 05Direction: outAttribute: 2Type: BulkMax Packet Size: 512Interval: 0msInterface Number: 5Name: Alternate Number: 0Class: ff(vend.) Sub Class: 06Protocol: 1bNumber of Endpoints: 2Endpoint Address: 88Direction: inAttribute: 2Type: BulkMax Packet Size: 512Interval: 0msEndpoint Address: 06Direction: outAttribute: 2Type: BulkMax Packet Size: 512Interval: 0msConfig Number: 2  //实际使用的配置Number of Interfaces: 7Attributes: a0MaxPower Needed:   2mAInterface Number: 0Name:cdc_etherAlternate Number: 0Class: 02(comm.) Sub Class: 06Protocol: 00Number of Endpoints: 1Endpoint Address: 82Direction: inAttribute: 3Type: Int.Max Packet Size: 16Interval: 2msInterface Number: 1 

Name: cdc_ether

Alternate Number: 0Class: 0a(data ) Sub Class: 06Protocol: 00Number of Endpoints: 2Endpoint Address: 81Direction: inAttribute: 2Type: BulkMax Packet Size: 512Interval: 0msEndpoint Address: 01Direction: outAttribute: 2Type: BulkMax Packet Size: 512Interval: 0msInterface Number: 2Name: optionAlternate Number: 0Class: ff(vend.) Sub Class: 06Protocol: 10Number of Endpoints: 3Endpoint Address: 84Direction: inAttribute: 3Type: Int.Max Packet Size: 10Interval: 32msEndpoint Address: 83Direction: inAttribute: 2Type: BulkMax Packet Size: 512Interval: 0msEndpoint Address: 02Direction: outAttribute: 2Type: BulkMax Packet Size: 512Interval: 0msInterface Number: 3Name: optionAlternate Number: 0Class: ff(vend.) Sub Class: 06Protocol: 13Number of Endpoints: 2Endpoint Address: 85Direction: inAttribute: 2Type: BulkMax Packet Size: 512Interval: 0msEndpoint Address: 03Direction: outAttribute: 2Type: BulkMax Packet Size: 512Interval: 0msInterface Number: 4Name: optionAlternate Number: 0Class: ff(vend.) Sub Class: 06Protocol: 12Number of Endpoints: 2Endpoint Address: 86Direction: inAttribute: 2Type: BulkMax Packet Size: 512Interval: 0msEndpoint Address: 04Direction: outAttribute: 2Type: BulkMax Packet Size: 512Interval: 0msInterface Number: 5Name: optionAlternate Number: 0Class: ff(vend.) Sub Class: 06Protocol: 06Number of Endpoints: 2Endpoint Address: 87Direction: inAttribute: 2Type: BulkMax Packet Size: 512Interval: 0msEndpoint Address: 05Direction: outAttribute: 2Type: BulkMax Packet Size: 512Interval: 0msInterface Number: 6Name: optionAlternate Number: 0Class: ff(vend.) Sub Class: 06Protocol: 1bNumber of Endpoints: 2Endpoint Address: 88Direction: inAttribute: 2Type: BulkMax Packet Size: 512Interval: 0msEndpoint Address: 06Direction: outAttribute: 2Type: BulkMax Packet Size: 512Interval: 0msConfig Number: 3Number of Interfaces: 2Attributes: a0MaxPower Needed:   2mAInterface Number: 0Name: Alternate Number: 0Class: 02(comm.) Sub Class: 0eProtocol: 00Number of Endpoints: 1Endpoint Address: 82Direction: inAttribute: 3Type: Int.Max Packet Size: 16Interval: 2msInterface Number: 1Name: Alternate Number: 0Class: 0a(data ) Sub Class: 00Protocol: 02Number of Endpoints: 0Interface Number: 1Name: Alternate Number: 1Class: 0a(data ) Sub Class: 00Protocol: 02Number of Endpoints: 2Endpoint Address: 81Direction: inAttribute: 2Type: BulkMax Packet Size: 512Interval: 0msEndpoint Address: 01Direction: outAttribute: 2Type: BulkMax Packet Size: 512Interval: 0ms

以上就是使用usbview软件查看的USB设备信息，这里对应这个ttyUSB0-ttyUSB4理解：

cdc_ether 1-1:2.0: usb0: register 'cdc_ether' at usb-s3c24xx-1, CDC Ethernet Device, 02:1e:10:1f:00:00option 1-1:2.2: GSM modem (1-port) converter detectedusb 1-1: GSM modem (1-port) converter now attached to ttyUSB0option 1-1:2.3: GSM modem (1-port) converter detectedusb 1-1: GSM modem (1-port) converter now attached to ttyUSB1option 1-1:2.4: GSM modem (1-port) converter detectedusb 1-1: GSM modem (1-port) converter now attached to ttyUSB2option 1-1:2.5: GSM modem (1-port) converter detectedusb 1-1: GSM modem (1-port) converter now attached to ttyUSB3option 1-1:2.6: GSM modem (1-port) converter detectedusb 1-1: GSM modem (1-port) converter now attached to ttyUSB4

目前还没有拿到证据，但在观看这里的1-1.2.0到最后的1-1.2.6，估计2代表使用的配置2，就是上面的Config Number为2的配置描述符，后边的数字从0、2、3、4、5、6代表了上边的接口描述符，可以从接口描述符名字观察到，其中配置描述符2的接口描述符1没有使用上。

二、关于option_instat_callback error -2的原因

   【1】函数内容：

static void option_instat_callback(struct urb *urb){int err;int status = urb->status;struct usb_serial_port *port =  urb->context;struct option_port_private *portdata = usb_get_serial_port_data(port);dbg("%s", __func__);dbg("%s: urb %p port %p has data %p", __func__, urb, port, portdata);if (status == 0) {struct usb_ctrlrequest *req_pkt =(struct usb_ctrlrequest *)urb->transfer_buffer;if (!req_pkt) {dbg("%s: NULL req_pkt", __func__);return;}if ((req_pkt->bRequestType == 0xA1) &&(req_pkt->bRequest == 0x20)) {int old_dcd_state;unsigned char signals = *((unsigned char *)urb->transfer_buffer +sizeof(struct usb_ctrlrequest));dbg("%s: signal x%x", __func__, signals);old_dcd_state = portdata->dcd_state;portdata->cts_state = 1;portdata->dcd_state = ((signals & 0x01) ? 1 : 0);portdata->dsr_state = ((signals & 0x02) ? 1 : 0);portdata->ri_state = ((signals & 0x08) ? 1 : 0);if (old_dcd_state && !portdata->dcd_state) {struct tty_struct *tty =tty_port_tty_get(&port->port);if (tty && !C_CLOCAL(tty))tty_hangup(tty);tty_kref_put(tty);}} else {dbg("%s: type %x req %x", __func__,req_pkt->bRequestType, req_pkt->bRequest);}++++++}else if(status ==-ENOENT || status == -ESHUTDOWN) {++++++         dbg("%s: urb stopped: %d\n", __func__, status);         }else               err("%s: error %d", __func__, status);/* Resubmit urb so we continue receiving IRQ data */if (status != -ESHUTDOWN && status != -ENOENT) {err = usb_submit_urb(urb, GFP_ATOMIC);if (err)dbg("%s: resubmit intr urb failed. (%d)",__func__, err);}}

找了好久，在linux-usb的邮件里边找到了一个人提交的patch，里边描述的问题正好就是option: option_instat_callback: error -2，综合了他的修改，同时在option.c文件前边加上dbg函数：

#ifdef CONFIG_USB_DEBUGstatic int mydebug = 5;#elsestatic int mydebug = 1;#endif/* Use our own dbg macro */#undef dbg#define dbg(format, arg...) \do { \ if(mydebug > 3)\printk(KERN_DEBUG "%s: " format "\n", __FILE__, ##arg);\} while (0)