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diff --git a/Documentation/usb/gadget_serial.txt b/Documentation/usb/gadget_serial.txt new file mode 100644 index 00000000000..a938c3dd13d --- /dev/null +++ b/Documentation/usb/gadget_serial.txt @@ -0,0 +1,332 @@ + + Linux Gadget Serial Driver v2.0 + 11/20/2004 + + +License and Disclaimer +---------------------- +This program is free software; you can redistribute it and/or +modify it under the terms of the GNU General Public License as +published by the Free Software Foundation; either version 2 of +the License, or (at your option) any later version. + +This program is distributed in the hope that it will be useful, +but WITHOUT ANY WARRANTY; without even the implied warranty of +MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the +GNU General Public License for more details. + +You should have received a copy of the GNU General Public +License along with this program; if not, write to the Free +Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, +MA 02111-1307 USA. + +This document and the the gadget serial driver itself are +Copyright (C) 2004 by Al Borchers (alborchers@steinerpoint.com). + +If you have questions, problems, or suggestions for this driver +please contact Al Borchers at alborchers@steinerpoint.com. + + +Prerequisites +------------- +Versions of the gadget serial driver are available for the +2.4 Linux kernels, but this document assumes you are using +version 2.0 or later of the gadget serial driver in a 2.6 +Linux kernel. + +This document assumes that you are familiar with Linux and +Windows and know how to configure and build Linux kernels, run +standard utilities, use minicom and HyperTerminal, and work with +USB and serial devices. It also assumes you configure the Linux +gadget and usb drivers as modules. + + +Overview +-------- +The gadget serial driver is a Linux USB gadget driver, a USB device +side driver. It runs on a Linux system that has USB device side +hardware; for example, a PDA, an embedded Linux system, or a PC +with a USB development card. + +The gadget serial driver talks over USB to either a CDC ACM driver +or 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 looks +like a serial device. + +On the host-side system, the gadget serial device looks like a +CDC ACM compliant class device or a simple vendor specific device +with bulk in and bulk out endpoints, and it is treated similarly +to other serial devices. + +The host side driver can potentially be any ACM compliant driver +or any driver that can talk to a device with a simple bulk in/out +interface. Gadget serial has been tested with the Linux ACM driver, +the Windows usbser.sys ACM driver, and the Linux USB generic serial +driver. + +With the gadget serial driver and the host side ACM or generic +serial driver running, you should be able to communicate between +the host and the gadget side systems as if they were connected by a +serial cable. + +The gadget serial driver only provides simple unreliable data +communication. It does not yet handle flow control or many other +features of normal serial devices. + + +Installing the Gadget Serial Driver +----------------------------------- +To use the gadget serial driver you must configure the Linux gadget +side kernel for "Support for USB Gadgets", for a "USB Peripheral +Controller" (for example, net2280), and for the "Serial Gadget" +driver. All this are listed under "USB Gadget Support" when +configuring the kernel. Then rebuild and install the kernel or +modules. + +The gadget serial driver uses major number 127, for now. So you +will need to create a device node for it, like this: + + mknod /dev/ttygserial c 127 0 + +You only need to do this once. + +Then you must load the gadget serial driver. To load it as an +ACM device, do this: + + modprobe g_serial use_acm=1 + +To load it as a vendor specific bulk in/out device, do this: + + modprobe g_serial + +This will also automatically load the underlying gadget peripheral +controller driver. This must be done each time you reboot the gadget +side Linux system. You can add this to the start up scripts, if +desired. + +If gadget serial is loaded as an ACM device you will want to use +either the Windows or Linux ACM driver on the host side. If gadget +serial is loaded as a bulk in/out device, you will want to use the +Linux generic serial driver on the host side. Follow the appropriate +instructions below to install the host side driver. + + +Installing the Windows Host ACM Driver +-------------------------------------- +To use the Windows ACM driver you must have the files "gserial.inf" +and "usbser.sys" together in a folder on the Windows machine. + +The "gserial.inf" file is given here. + +-------------------- CUT HERE -------------------- +[Version] +Signature="$Windows NT$" +Class=Ports +ClassGuid={4D36E978-E325-11CE-BFC1-08002BE10318} +Provider=%LINUX% +DriverVer=08/17/2004,0.0.2.0 +; Copyright (C) 2004 Al Borchers (alborchers@steinerpoint.com) + +[Manufacturer] +%LINUX%=GSerialDeviceList + +[GSerialDeviceList] +%GSERIAL%=GSerialInstall, USB\VID_0525&PID_A4A7 + +[DestinationDirs] +DefaultDestDir=10,System32\Drivers + +[GSerialInstall] +CopyFiles=GSerialCopyFiles +AddReg=GSerialAddReg + +[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" +-------------------- CUT HERE -------------------- + +The "usbser.sys" file comes with various versions of Windows. +For example, it can be found on Windows XP typically in + + C:\WINDOWS\Driver Cache\i386\driver.cab + +Or it can be found on the Windows 98SE CD in the "win98" folder +in the "DRIVER11.CAB" through "DRIVER20.CAB" cab files. You will +need the DOS "expand" program, the Cygwin "cabextract" program, or +a similar program to unpack these cab files and extract "usbser.sys". + +For example, to extract "usbser.sys" into the current directory +on Windows XP, open a DOS window and run a command like + + expand C:\WINDOWS\Driver~1\i386\driver.cab -F:usbser.sys . + +(Thanks to Nishant Kamat for pointing out this DOS command.) + +When the gadget serial driver is loaded and the USB device connected +to the Windows host with a USB cable, Windows should recognize the +gadget serial device and ask for a driver. Tell Windows to find the +driver in the folder that contains "gserial.inf" and "usbser.sys". + +For example, on Windows XP, when the gadget serial device is first +plugged in, the "Found New Hardware Wizard" starts up. Select +"Install from a list or specific location (Advanced)", then on +the next screen select "Include this location in the search" and +enter the path or browse to the folder containing "gserial.inf" and +"usbser.sys". Windows will complain that the Gadget Serial driver +has not passed Windows Logo testing, but select "Continue anyway" +and finish the driver installation. + +On Windows XP, in the "Device Manager" (under "Control Panel", +"System", "Hardware") expand the "Ports (COM & LPT)" entry and you +should see "Gadget Serial" listed as the driver for one of the COM +ports. + +To uninstall the Windows XP driver for "Gadget Serial", right click +on the "Gadget Serial" entry in the "Device Manager" and select +"Uninstall". + + +Installing the Linux Host ACM Driver +------------------------------------ +To use the Linux ACM driver you must configure the Linux host side +kernel for "Support for Host-side USB" and for "USB Modem (CDC ACM) +support". + +Once the gadget serial driver is loaded and the USB device connected +to the Linux host with a USB cable, the host system should recognize +the gadget serial device. For example, the command + + cat /proc/bus/usb/devices + +should show something like this: + +T: Bus=01 Lev=01 Prnt=01 Port=01 Cnt=02 Dev#= 5 Spd=480 MxCh= 0 +D: Ver= 2.00 Cls=02(comm.) Sub=00 Prot=00 MxPS=64 #Cfgs= 1 +P: Vendor=0525 ProdID=a4a7 Rev= 2.01 +S: Manufacturer=Linux 2.6.8.1 with net2280 +S: Product=Gadget Serial +S: SerialNumber=0 +C:* #Ifs= 2 Cfg#= 2 Atr=c0 MxPwr= 2mA +I: If#= 0 Alt= 0 #EPs= 1 Cls=02(comm.) Sub=02 Prot=01 Driver=acm +E: Ad=83(I) Atr=03(Int.) MxPS= 8 Ivl=32ms +I: If#= 1 Alt= 0 #EPs= 2 Cls=0a(data ) Sub=00 Prot=00 Driver=acm +E: Ad=81(I) Atr=02(Bulk) MxPS= 512 Ivl=0ms +E: Ad=02(O) Atr=02(Bulk) MxPS= 512 Ivl=0ms + +If the host side Linux system is configured properly, the ACM driver +should be loaded automatically. The command "lsmod" should show the +"acm" module is loaded. + + +Installing the Linux Host Generic USB Serial Driver +--------------------------------------------------- +To use the Linux generic USB serial driver you must configure the +Linux host side kernel for "Support for Host-side USB", for "USB +Serial Converter support", and for the "USB Generic Serial Driver". + +Once the gadget serial driver is loaded and the USB device connected +to the Linux host with a USB cable, the host system should recognize +the gadget serial device. For example, the command + + cat /proc/bus/usb/devices + +should show something like this: + +T: Bus=01 Lev=01 Prnt=01 Port=01 Cnt=02 Dev#= 6 Spd=480 MxCh= 0 +D: Ver= 2.00 Cls=ff(vend.) Sub=00 Prot=00 MxPS=64 #Cfgs= 1 +P: Vendor=0525 ProdID=a4a6 Rev= 2.01 +S: Manufacturer=Linux 2.6.8.1 with net2280 +S: Product=Gadget Serial +S: SerialNumber=0 +C:* #Ifs= 1 Cfg#= 1 Atr=c0 MxPwr= 2mA +I: If#= 0 Alt= 0 #EPs= 2 Cls=0a(data ) Sub=00 Prot=00 Driver=serial +E: Ad=81(I) Atr=02(Bulk) MxPS= 512 Ivl=0ms +E: Ad=02(O) Atr=02(Bulk) MxPS= 512 Ivl=0ms + +You must explicitly load the usbserial driver with parameters to +configure it to recognize the gadget serial device, like this: + + modprobe usbserial vendor=0x0525 product=0xA4A6 + +If everything is working, usbserial will print a message in the +system log saying something like "Gadget Serial converter now +attached to ttyUSB0". + + +Testing with Minicom or HyperTerminal +------------------------------------- +Once the gadget serial driver and the host driver are both installed, +and a USB cable connects the gadget device to the host, you should +be able to communicate over USB between the gadget and host systems. +You can use minicom or HyperTerminal to try this out. + +On the gadget side run "minicom -s" to configure a new minicom +session. Under "Serial port setup" set "/dev/ttygserial" as the +"Serial Device". Set baud rate, data bits, parity, and stop bits, +to 9600, 8, none, and 1--these settings mostly do not matter. +Under "Modem and dialing" erase all the modem and dialing strings. + +On a Linux host running the ACM driver, configure minicom similarly +but use "/dev/ttyACM0" as the "Serial Device". (If you have other +ACM devices connected, change the device name appropriately.) + +On a Linux host running the USB generic serial driver, configure +minicom similarly, but use "/dev/ttyUSB0" as the "Serial Device". +(If you have other USB serial devices connected, change the device +name appropriately.) + +On a Windows host configure a new HyperTerminal session to use the +COM port assigned to Gadget Serial. The "Port Settings" will be +set automatically when HyperTerminal connects to the gadget serial +device, so you can leave them set to the default values--these +settings mostly do not matter. + +With minicom configured and running on the gadget side and with +minicom or HyperTerminal configured and running on the host side, +you should be able to send data back and forth between the gadget +side and host side systems. Anything you type on the terminal +window on the gadget side should appear in the terminal window on +the host side and vice versa. + + |