Linux ACP Modem (Mwave) mini-HOWTO

1.1. Introduction

The ACP Modem for Linux is a software based modem. Support software for the ACP modem is composed of a loadable kernel module and a user level application. Together these components support direct connection to public switched telephone networks (PSTNs) and support selected countries world wide. Refer to Section 6 of this document for the supported country list.

The modem also supports the standard communications port interface (ttySx) and is compatible with the Hayes AT Command Set.

ACP Modem software is continually under development. If you encounter bugs or usability issues, please contact us and we'll work to correct them.

1.2. Credits

This Linux ACP Modem driver was ported from the Windows NT™ version of the driver available from IBM. Many thanks to Keith Frechette, Charles Ball, and Frank Novak for their technical and support efforts in making this project possible.

1.3. Where Can I Get the Latest Version of this Driver?

The latest version of this driver is available from http://www.ibm.com/linux/ltc/

1.4. Are There Any Other Resources?

Thomas Hood's Debian GNU/Linux on IBM ThinkPad 600 and 600x page contains lots of useful information.

1.5. Copyright Notice and Disclaimer

Copyright (c) 2002 IBM Corporation

This document may be reproduced or distributed in any form without prior permission. Modified versions of this document may be freely distributed, provided that they are clearly identified as such, and this copyright is included intact.

This document is provided "AS IS", with no express or implied warranties. Use the information in this document at your own risk.

1.6. Which Systems are Supported

This version of the ACP Modem driver supports the IBM Thinkpad™ 600E, 600, and 770 that include on-board ACP modem hardware.

1.7. Features of the Modem

The ACP Modem provides the following features:

• Standard asynchronous COM port interface (NS16550A UART compatible) operation

• Bell-103/212A, CCITT-V.21/V.22,V.22bis protocols with data from 300 to 2400 bps

• CCITT-V.32 protocols with data rates of 4800, 9600 uncoded, and 9600 bps Trellis coded (Optional)

• CCITT-V.32bis protocols with data rates of 4800, 9600, 12000, and 14400 bps (optional)

• ITU-T V.34 protocols with data rates from 2400 to 33600 bps.

• 56K capable modem

• Hayes AT Command Set compatibility

• DTMF and pulse dialing

• Asynchronous error recovery protocol

• Error correction via Microcom Network Protocol (MNP) classes 1-4

• Error correction via the V.42 error correction standard

• MNP class 5 for up to 2x data compression

• V.42bis for up to 4x data compression

• "Adaptive Rate Negotiation" which provides for "Fallback / Fallforward" as line quality deteriorates or improves

Your modem contains 56K technology. To take advantage of this technology, you must first make sure that your Internet Service Provider (ISP) supports a 56K modem protocol. Significantly higher modem connection speeds, up to 56kbps, require all-digital transmission connections from your ISP to the line card in the central office from which your phone line is connected. The actual connection rate may be limited by the quality of your telephone lines. Telephone line quality may vary from location to location. Current regulations limit maximum trasfer rates to 53K. While your modem contains 56K technology, typical maximum connection rates in the receive direction may be significantly less than 56K. Currently, 56K capability is for the receive direction only. The transmit direction uses V.34 technology.

2.1. Prerequisites

• A 2.2.16 series (or later) Linux kernel source tree

• An appropriate set of module utilities

• gcc version 2.7.x or later

If you are building the ACP Modem driver along with the user space application, you need to have a complete Linux source tree for your kernel, not just an up-to-date kernel image.

2.2. Building and Installing Source

1. Use tar xzvf mwavem-yyyymmdd.tar.gz to unpack the distribution.

2. Change directories with cd mwavem-yyyymmdd

3. Use the ./configure command to configure the build options. Issue ./configure --help to view all of the options. The defaults are probably okay though.

   	NOTE
   	As of mwavem-1.0.3 you must give ./configure the --enable-mwavedd argument in order to build the driver with the user space application.

4. Use the make command to build all of the ACP Modem binaries.

   	NOTE
   	Your gcc package should be at least at the 2.7.x level. Check your /usr/src/linux/Documentation/Changes file for the minimum version information.

5. Use make install to install the mwavem binary, mwavem.conf configuration, the extra binary (mostly .dsp) files, and module device driver (if you specified that it must be built) and to create the /dev/modems/mwave device node.

2.3. Setting Things Up

In the [WORLDTRADE] section of your mwavem.conf file, set the Country= parameter to your country access code.

	NOTE
	The mwavem.conf file is installed in the /usr/local/etc directory unless you specified otherwise during the build process

Country information (including access codes) are listed in the mwavem.conf file. For example, for France the following section is present:

[Telephony\Country List\33]

CountryCode=00000021

Name=France

SameAreaRule=0FG

LongDistanceRule=0FG

InternationsalRule=00EFG

To set France to be your configured country in the [WORLDTRADE] section of mwavem.conf,

set Country=33

2.4. Runtime

An initialization script has been provided which may be used to to start, stop, or check the status of the ACP Modem driver and application. It has been successfully run on the Debian, Slackware, SuSE, and Red Hat distributions and should run on any of their derivitives. If you are using the runtime script, it will load the mwave device driver module, configure the serial port, and start the mwave manager for you. All of the options which can be passed to the device driver module, along with some options for the script itself, can be configured by uncommenting and editing the appropriate variables at the beginning of the script.

The mwaved startup script can be found in the src/mwavem directory of the source distribution. If you are running the Red Hat distribution, you can copy the script to your /etc/rc.d/init.d directory and issue the ntsysv command in order to enable it at boot time. If not using Red Hat, see the documentation for your distribution for information on how to set this up to run at boot time.

It is recommended that you use the provided mwaved script. If you are not using the script, however, the following sections will describe how to manually start the device driver and application.

---

2.4.1. Loading the ACP device driver

To load the mwave device driver use

insmod mwave

or

modprobe mwave

The following arguments may be supplied with the insmod command:

	NOTE
	The following arguments are not persistent from boot to boot (i.e. We are not saving them in the BIOS).

• mwave_3780i_irq=5/7/10/11/15

  This parameter allows you to configure the IRQ used by the DSP if the DSP IRQ was not set and stored in BIOS by the Thinkpad™ configuration utility.

• mwave_3780i_io=0x130/0x350/0x0070/0xDB0

  This parameter allows you to configure the I/O range used by the DSP if the DSP I/O range was not set and stored in the BIOS by the Thinkpad™ configuration utility.

• mwave_uart_irq=3/4

  This parameter allows you to configure the IRQ used by the ACP UART if the Mwave's UART IRQ was not set and stored in BIOS by the Thinkpad™ configuration utility.

• mwave_uart_io=0x3f8/0x2f8/0x3E8/0x2E8

  This parameter allows you to configure the I/O range used by the ACP UART if the UART I/O range was not set and stored in BIOS by the Thinkpad™ configuration utility.

The following code is an example of how to run DSP using ttyS1 resources:

insmod mwave mwave_3780i_irq=10 mwave_3780i_io=0x0130 mwave_uart_irq=3 mwave_uart_io=0x2f8

	NOTE
	The mwave is unable to check for resource conflicts. It is your responsibility to ensure that none of the resources specified conflict with other (commonly PCMCIA) devices.

You can use the tpctl package on Linux or the Thinkpad™ configuration utility on Windows NT or DOS to manage the configuration of Thinkpad™ related resources.

3.1. DSP Does Not Start

In order to recognize memory above 64 Meg, it may be necessary to append the "mem=" option to the kernel command line. If you are using LILO for your boot loader, you would do this in the lilo.conf file. For example, if you had a machine with 128 Meg you would type:

append="mem=130496K"

	NOTE
	Your statement must reflect 576K less than you actually have. Specifying the full amount of memory will prevent the DSP from starting. In the above example, the formula used to arrive at the proper number was 1024 * nMB - 576 = nK.

If you forget to run the Thinkpad™ utility to enable the ACP Modem and you didn't specify any command line arguments when inserting the mwave module (or it didn't work), you will receive a message in the syslog, similar to the one below:

ACP Modem, UART settings IRQ 0x3	IO 0x2f8

tp3780::EnableDSP, pSettings->bDSPEnabled 0 failed

Mwave Modem, ERROR cannot Enable DSP error fffffffb

Mwave Modem, ERROR cannot perform Mwave Initialization retval fffffffb

If you receive a message like the one above, check the command line arguments you provided to insmod.

3.2. Resource Conflicts

The ACP Modem requires the use of system resources for both the DSP and the UART provided by the ACP chip. For Linux systems, you will specify parameters to use for the duration of the boot with the insmod mwave command line parameters listed in Section 2.4.1.

Typically the configured resources are:

For the DSP:  IRQ 10, I/O address 0x130-0x13f

For the UART: IRQ 3,  I/O address 0x2f8 (if using ttyS1)

				  IRQ 4,  I/O address 0x3f8 (if using ttyS0)

For dual boot systems we recommeded that you use the Thinkpad™ Configuration Utility on Windows NT or DOS to configure these system resources.

Windows NT Thinkpad Configuration Utility Notes: (Under the Internal Modem --> Advanced selection)

1. Set IRQ sharing to disabled

2. Set 1st IRQ to your DSP IRQ (10 is recommened)

3. Set 2nd IRQ to your UART IRQ (i.e. ttyS1 is equivalent to COM2)

4. Set the DSP I/O address (0x130 is recommended)

5. Set the internal modem I/O address to the UART I/O address (i.e. 0x2f8 for COM2)

6. The DMA address is unused and can be set to anything.

	NOTE
	You may also specify parameters to use for the duration of the boot by using the insmod mwave line parameters listed in section Section 2.4.1.

3.3. Not Connecting at Specified Starting Speed

The configured initial connection speed is set to 64000. The modem should start there and negotiate down to a connection speed based on target modem and line capabilities. If the modem is unable to connect it may be having difficulty negotiating with the target modem. Try setting the SPEED parameter in mwavem.conf to a lower initial starting speed. Supported speeds include:

• 64000

• 33600

• 14400

• 9600

• 2400

3.4. Dialer Application Cannot Detect Serial Port

The startup script that executes the serial port setup works well with Red Hat, Debian, Slackware, and SuSE. If you are not running one of these distributions, you may need to perform the following steps in order to set up.

After inserting the mwave.o module and starting the mwavem application, you must run the setserial command in order for the serial port configuration to discover the UART on the mwave hardware:

setserial /dev/ttySx autoconfig

Replace ttySx with the serial port you have configured the ACP driver to use.

To test whether the serial port is setup correctly, run:

setserial /dev/ttySx

The above command should return the following for serial port 1:

/dev/ttyS1, UART: 16550A, Port: 0x2f8, IRQ: 3

The port and IRQ numbers should match the information placed in the syslog by the ACP module when it was loaded:

kernel: Mwave Modem, UART settings IRQ 0x3 IO 0x2f8

If the information returned by setserial indicates that the UART is 'unknown' or if the IRQ and I/O resources do not match what you have in the syslog, you will need to reconfigure. Check the setserial man pages to learn how to setup the resources on your ttySx to match what appears in the syslog output.

If you have problems running setserial, you may have a resource conflict. Before using insmod mwave, check /proc/ioports and /proc/interrupts to make sure the resources you intend to claim are not already in use.

3.5. PPP Errors Using 2.4.0 Version of the Kernel

When upgrading to the 2.4.0 version of the kernel be sure to read the ./Documentation/Changes file. Kernel 2.4.0 requires an upgraded version of the pppd, gcc, and modutils (amoung other things). Follow the instructions for setting up the new pppd daemon carefully.

You may experience some initial problems getting ppp running with 2.4.0. One of the most prevelant errors we received was, "Can't locate module tty-ldisc-3." However, we had no problems once we rebuilt the kernel with the following options:

CONFIG_PPP=y

CONFIG_PPP_ASYNC=m

CONFIG_PPP_SYNC_TTY=m

CONFIG_PPP_DEFLATE=m

CONFIG_PPP_BSDCOM=m 

4.1. Error Logs

Errors encountered by the ACP Modem device driver or application are logged using the syslog utility.

4.2. Tracing

The ACP device driver supports a debug argument to enable the generation of trace information. The command for this debug is listed below. You can also access several of the variables listed below in the mwaved script.

insmod mwave mwave_debug=0x0f

Where the following debug trace information is selectable:

0x01	ACP Modem Device driver entry points

0x02	Systems Management API(SMAPI)

0x04	Hardware Interface (3780I)

0x08	Thinkpad Interface (tp3780i)

Trace information is logged using the syslog utility.

The ACP application supports tracing through the use of flags configured in the [STARTUP] section of the mwavem.conf file.

Mwave Manager API trace points:

MANAGER_API_TRACE=1

MANAGER_API_DATA_TRACE=1

MANAGER_CORE_TRACE=1

MANAGER_SPECIFIC_TRACE=1

MEIO Manager trace points:

MEIO_API_TRACE=1

MEIO_CORE_TRACE=1

MEIO_SPECIFIC_TRACE=1

Mwave Modem application trace points:

MWMLW32_TRACE=1

MWMPW32_TRACE=1

MWMUTIL_TRACE=1

MWWTT32_TRACE=1

Trace information is logged using the syslog utility.