安徽工程建设信息网站,亚马逊一个月赚5万难吗,济南竞价托管公司,解答网站内容优化策略Linux内核中usb设备侧驱动程序分成3个层次#xff1a;UDC驱动程序、Gadget API和Gadget驱动程序。UDC驱动程序(USB控制器)直接访问硬件#xff0c;控制USB设备和主机间的底层通信#xff0c;向上层提供与硬件相关操作的回调函数。Gadget API是UDC驱动程序回调函数的简单包装…Linux内核中usb设备侧驱动程序分成3个层次UDC驱动程序、Gadget API和Gadget驱动程序。UDC驱动程序(USB控制器)直接访问硬件控制USB设备和主机间的底层通信向上层提供与硬件相关操作的回调函数。Gadget API是UDC驱动程序回调函数的简单包装这部分程序内核都已经写好。Gadget驱动程序具体控制USB设备功能的实现使设备表现出“U盘”、“虚拟串口”等特性。简单看个usb 虚拟串口例子Overview--------The gadget serial driver is a Linux USB gadget driver, a USB deviceside driver. It runs on a Linux system that has USB device sidehardware; for example, a PDA, an embedded Linux system, or a PCwith a USB development card.The gadget serial driver talks over USB to either a CDC ACM driveror a generic USB serial driver running on a host PC.Host-------------------------------------- | Host-Side CDC ACM USB Host | | Operating | or | Controller | USB | System | Generic USB | Driver |-------- | (Linux or | Serial | and | | | Windows) Driver USB Stack | | -------------------------------------- | | | | Gadget | -------------------------------------- | | Gadget USB Periph. | | | Device-Side | Gadget | Controller | | | Linux | Serial | Driver |-------- | Operating | Driver | and | | System USB Stack | --------------------------------------On the device-side Linux system, the gadget serial driver lookslike a serial device.On the host-side system, the gadget serial device looks like aCDC ACM compliant class device or a simple vendor specific devicewith bulk in and bulk out endpoints, and it is treated similarlyto other serial devices.The host side driver can potentially be any ACM compliant driveror any driver that can talk to a device with a simple bulk in/outinterface. Gadget serial has been tested with the Linux ACM driver,the Windows usbser.sys ACM driver, and the Linux USB generic serialdriver.With the gadget serial driver and the host side ACM or genericserial driver running, you should be able to communicate betweenthe host and the gadget side systems as if they were connected by aserial cable.The gadget serial driver only provides simple unreliable datacommunication. It does not yet handle flow control or many otherfeatures of normal serial devices.内核版本3.15 硬件ATMEL SAMA5D3 编译环境ubuntu 12.041、配置内核这里之所以都选择为模块的形式是为了调试方便有些模块比如U盘加载时还需要提供介质就是说加载模块时还需要参数否则加载不上Device Drivers ---[*] USB support --- USB Gadget Support --- USB Gadget Drivers USB functions configurable through configfs Gadget Zero (DEVELOPMENT) Ethernet Gadget (with CDC Ethernet support) Network Control Model (NCM) support Gadget Filesystem Function Filesystem Mass Storage Gadget USB Gadget Target Fabric Module Serial Gadget (with CDC ACM and CDC OBEX support) Printer Gadget保存退出编译内核。在drivers/usb/gadget目录下会生成以下驱动文件-rw-rw-r-- 1 a_tu a_tu 9710 3月 5 15:14 ./g_serial.ko-rw-rw-r-- 1 a_tu a_tu 49319 3月 5 15:14 ./libcomposite.ko-rw-rw-r-- 1 a_tu a_tu 11473 3月 5 15:14 ./usb_f_acm.ko-rw-rw-r-- 1 a_tu a_tu 9485 3月 5 15:14 ./usb_f_obex.ko-rw-rw-r-- 1 a_tu a_tu 8011 3月 5 15:14 ./usb_f_serial.ko-rw-rw-r-- 1 a_tu a_tu 15970 3月 5 15:14 ./u_serial.ko2、操作开发板把编译好的内核烧入开发板加载生成的驱动文件注意加载顺序否则会出现错误。insmod u_serial.koinsmod libcomposite.koinsmod usb_f_serial.koinsmod usb_f_obex.koinsmod usb_f_acm.koinsmod g_serial.ko出现内核信息如下[ 27.310000] --------filecomposite.c-------usb_composite_probe------1830[ 27.320000] ------------402[ 27.320000] -----usb_gadget_probe_driver------411[ 27.330000] -------udc_bind_to_driver-----342[ 27.330000] g_serial gadget: Gadget Serial v2.4[ 27.340000] g_serial gadget: g_serial ready[ 18.960000] g_serial gadget: high-speed config #2: CDC ACM config说明加载成功。此时你打开设备管理器会发现多了一个串口设备ELMO GMAS(COM10)Win7操作系统可以自动加载基于udc标准的serial驱动。对于WinXP操作系统要使用ACM串口需要WindowsXP机器上有gserial.inf和usbser.sys这两个文件其中gserial.inf的配置如下[Version] Signature$Windows NT$ ClassPorts ClassGuid{4D36E978-E325-11CE-BFC1-08002BE10318} Provider%LINUX% DriverVer08/17/2004,0.0.2.0 ; Copyright (C) 2004 Al Borchers (alborcherssteinerpoint.com) [Manufacturer] %LINUX%GSerialDeviceList [GSerialDeviceList] %GSERIAL%GSerialInstall, USB\VID_0525PID_A4A7 [DestinationDirs] DefaultDestDir10,System32\Drivers [GSerialInstall] CopyFilesGSerialCopyFiles AddRegGSerialAddReg [GSerialCopyFiles] usbser.sys [GSerialAddReg] HKR,,DevLoader,,*ntkern HKR,,NTMPDriver,,usbser.sys HKR,,EnumPropPages32,,MsPorts.dll,SerialPortPropPageProvider [GSerialInstall.Services] AddService usbser,0x0002,GSerialService [GSerialService] DisplayName %GSERIAL_DISPLAY_NAME% ServiceType 1 ; SERVICE_KERNEL_DRIVER StartType 3 ; SERVICE_DEMAND_START ErrorControl 1 ; SERVICE_ERROR_NORMAL ServiceBinary %10%\System32\Drivers\usbser.sys LoadOrderGroup Base [Strings] LINUX Linux GSERIAL Gadget Serial GSERIAL_DISPLAY_NAME USB Gadget Serial Driver安装成功后在设备管理器中可以看到 “Gadget Serial (COM11) 这个端口。开发板的/dev/下会出现/dev/ttyGS0这个设备。当然如果你怕这个设备重名可以更改这个设备节点。操作如下cat /proc/devicesCharacter devices: 1 mem 2 pty 3 ttyp 4 /dev/vc/0 4 tty 4 ttyS 5 /dev/tty 5 /dev/console 5 /dev/ptmx 7 vcs 10 misc 13 input 90 mtd 128 ptm 136 pts 153 spi 251 ttyGSmknod /dev/usb_serial c 254 0以后可以直接按照串口通讯的方式打开该节点 /dev/usb_serial进行数据读写操作。3、通信测试开发板上执行命令 cat /dev/usb_serial(当然你也可以编写程序打开设备读写)这里只是简单的测试设备通信是否正常 pc机上打开串口调试助手打开com10通过字符串输入框发送数据。此时发现开发板没有收到数据而串口助手却收到自己发送的数据。这让我很是纳闷折腾了2天终于睡醒了。又测试了另一通路开发板给pc发。echo 12345 /dev/usb_serial这是完全正常的通过串口助手收到的数据来看。每次收到的数据都有换行现象会不会是数据没有从缓冲区中刷出来我就换了数据格式发送简单文件111111111111111111222222222222222222222222222222222222444444444444444444此时开发板收到数据# cat /dev/usb_serial111111111111111111222222222222222222222222222222222222444444444444444444原来真的是 \n 在作怪如果你的文件只有一行且没有换行。那么你的开发板是收不到数据的这些数据并没有丢失而是存储在串口的缓冲区中直到遇到 \n,才会把数据一股脑发出来。至此测试完毕。本人水平有限文章仅代表个人观点如有错误请指正
