177 lines
5.5 KiB
Groff
177 lines
5.5 KiB
Groff
.\" $NetBSD: ntwoc.4,v 1.2 2001/06/12 11:35:03 wiz Exp $
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.\"
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.\" Copyright (c) 2000 Christian E. Hopps
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.\" All rights reserved.
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.\"
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.\" Redistribution and use in source and binary forms, with or without
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.\" modification, are permitted provided that the following conditions
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.\" are met:
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.\" 1. Redistributions of source code must retain the above copyright
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.\" notice, this list of conditions and the following disclaimer.
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.\" 2. Redistributions in binary form must reproduce the above copyright
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.\" notice, this list of conditions and the following disclaimer in the
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.\" documentation and/or other materials provided with the distribution.
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.\" 3. The name of the author may not be used to endorse or promote products
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.\" derived from this software without specific prior written permission
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.\"
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.\" THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
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.\" IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
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.\" OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
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.\" IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
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.\" INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
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.\" NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
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.\" DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
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.\" THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
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.\" (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
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.\" THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
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.\"
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.Dd October 2, 1998
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.Dt NTWOC 4
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.Os
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.Sh NAME
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.Nm ntwoc
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.Nd Riscom/N2, N2pci, WANic/400 synchronous serial interfaces
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.Sh SYNOPSIS
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.Cd "ntowc* at pci? dev ? function ? flags 0"
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.Cd "ntowc0 at isa? port 0x300 irq 5 iomem 0xc8000 flags 1"
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.Sh DESCRIPTION
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The
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.Nm
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device driver supports bit-synchronous serial communication using
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Cisco HDLC framing. The cards are capable of being driven by
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the line clock or from an internal baud rate generator.
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The devices all use the Hitachi hd64570 serial chip.
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The hd64570 supports 2 asynchronous/byte-synchronous/bit-synchronous
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serial ports, and has a 4-channel DMA controller for loading
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the serial port FIFOs.
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.Pp
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The isa Riscom/N2 card has a jumper block to set the irq and a DIP switch
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to set the port address the card will use. The values programmed
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into the card must be specified with the
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.Cm port
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and
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.Cm irq
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locators in the kernel configuration line.
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The
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.Cm iomem
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locator must be specified and must occur on a 16k boundary.
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The driver utilizes a 16k region of io memory. Bit 0 of the
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.Cm flags
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locator indicates if there is a second serial port available on the
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card.
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.Pp
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Currently
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clock source and speed information is specified with the
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.Cm flags
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locator in the kernel configuration file. The flags field has the
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following format.
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.Bd -literal
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3 2 1
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1 0 9 8 7 6 5 4 3 2 1 0 9 8 7 6 5 4 3 2 1 0 9 8 7 6 5 4 3 2 1 0
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+-------------+ +-----+ +-----+ + +---+ +-+ + +---+ +-+ +
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tmc tdiv rdiv e1 rxs1 ts1 e0 rxs0 txs0 np(*)
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.Ed
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.Bl -tag -width "rxs0 rxs1"
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.It Va tmc
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Defines the timer constant. The base clock frequency is divided
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by
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.Va tmc
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to generate the main clock for receiving and sending. Further
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division is possible with the
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.Va tdiv
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and
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.Va rdiv
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divisor options. A value of 0 is treated as 256.
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.It Va tdiv
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Defines the transmit divisor as
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.Pf "2^(" Va tdiv ) .
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The internal transmit clock
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frequency is determined by dividing the base clock frequency by
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.Va tmc
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and then dividing by
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.Pf "2^(" Va tdiv ) .
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.It Va rdiv
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Defines the receive divisor as
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.Pf "2^(" Va rdiv ) .
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The internal receive clock
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frequency is determined by dividing the base clock frequency by
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.Va tmc
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and then dividing by
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.Pf "2^(" Va rdiv ) .
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.It Va e0 Va e1
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If true the internal clock source is used to drive the line clock for port 0
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or port 1 respectively.
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.It Va rxs0 Va rxs1
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Specifies which clock source to use for receiving data on port 0 and
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port 1 respectively. The following values are accepted:
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.Pp
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.Bl -tag -width "000" -compact
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.It 0
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Line clock.
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.It 1
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Line clock with noise suppression.
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.It 2
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Internal clock.
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.El
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.It Va txs0 Va txs1
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Specifies which clock source to use for transmitting data on port 0
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and port 1 respectively. The following values are accepted:
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.Pp
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.Bl -tag -width "000" -compact
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.It 0
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Line clock.
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.It 1
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Internal clock.
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.It 2
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Receive clock.
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.El
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.It Va np
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(For the isa card only) A value of 1 indicates there is a second serial
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port present on the card. This is auto-detected on the pci card and need
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not be specified.
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.El
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.Pp
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.Sh HARDWARE
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Cards supported by the
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.Nm
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driver include:
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.Pp
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.Bl -item -compact
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.It
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SDL Communications Riscom/N2
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.It
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SDL Communications N2pci
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.It
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SDL Communications WAN/ic 400 (untested)
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.El
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.Sh DIAGNOSTICS
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.Bl -diag
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.It "ntwo0: TXDMA underrun - fifo depth maxed"
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Indicates that the serial port's FIFO is being drained faster
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than DMA can fill it. The driver automatically increases the
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low-water mark at which to begin dma transfers when underruns
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occur. This diagnostic is issued when the low-water mark is
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maximized (i.e., 1 less than the depth of the FIFO).
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.It "ntwo0: RXDMA buffer overflow"
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Indicates that a frame is being received by the card, but
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there are no free receive buffers.
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.El
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.Sh BUGS
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Use of the
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.Cm flags
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locator for setting the clock sources and speeds should be replaced with
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ioctl's and a control program.
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.Sh SEE ALSO
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.Xr intro 4 ,
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.Xr isa 4 ,
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.Xr pci 4 ,
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.Xr ifconfig 8
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.Sh HISTORY
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The pci driver first appeared in
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.Nx 1.4 .
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Much of the isa driver was adapted from the
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.Fx
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.Nm sr
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driver and first appeared in
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.Nx 1.5 .
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