1.\" $OpenBSD: cy.4,v 1.17 2020/07/23 22:33:29 jan Exp $ 2.\" 3.\" Copyright (c) 1993 Andrew Herbert. 4.\" All rights reserved. 5.\" 6.\" Redistribution and use in source and binary forms, with or without 7.\" modification, are permitted provided that the following conditions 8.\" are met: 9.\" 1. Redistributions of source code must retain the above copyright 10.\" notice, this list of conditions and the following disclaimer. 11.\" 2. Redistributions in binary form must reproduce the above copyright 12.\" notice, this list of conditions and the following disclaimer in the 13.\" documentation and/or other materials provided with the distribution. 14.\" 3. The name Andrew Herbert may not be used to endorse or promote products 15.\" derived from this software without specific prior written permission. 16.\" 17.\" THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR 18.\" IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES 19.\" OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. 20.\" IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, 21.\" INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT 22.\" NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, 23.\" DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY 24.\" THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT 25.\" (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF 26.\" THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. 27.\" 28.Dd $Mdocdate: July 23 2020 $ 29.Dt CY 4 30.Os 31.Sh NAME 32.Nm cy 33.Nd Cyclades Cyclom-{4, 8, 16}Y asynchronous comms board device driver 34.Sh SYNOPSIS 35.Cd "cy0 at isa? iomem 0xd4000 irq 12" 36.Cd "cy* at pci?" 37.Sh DESCRIPTION 38This driver provides an interface to Cyclades Cyclom-4Y, Cyclom-8Y and 39Cyclom-16Y asynchronous multiport serial boards. 40These boards are based around Cirrus Logic CD1400 communication controllers. 41.Pp 42The device minor numbers for this driver are encoded as follows: 43.Bd -literal 44 d c c u u u u u - bits in the minor device number 45 46 bits meaning 47 ---- ------- 48 uuuuu physical serial line (i.e., unit) to use 49 0-7 on a cyclom-8Y, 0-15 on a cyclom-16Y 50 51 cc card number 52 53 d dial-out flag 54.Ed 55.Sh DIAGNOSTICS 56.Bl -diag 57.It "cy0: port 0 ibuf overrun" 58Incoming characters have been discarded due to a buffer overflow. 59.It "cy0: port 0 fifo overrun" 60Incoming characters have been discarded due to a CD1400 channel overrun. 61This is caused by interrupts not being serviced sufficiently quickly to prevent 62the 12 byte receive FIFO on a serial channel from overflowing. 63Reducing the value of the 64.Dv RX_FIFO_THRESHOLD 65#define from 6 to something smaller may help slow machines avoid this problem. 66.El 67.Sh SEE ALSO 68.Xr com 4 , 69.Xr intro 4 , 70.Xr isa 4 , 71.Xr pci 4 , 72.Xr termios 4 , 73.Xr tty 4 74.Sh HISTORY 75Some ideas for the architecture of this driver's two-layer processing model 76were derived from the fas 2.10 driver by 77.An Uwe Doering Aq Mt gemini@geminix.in-berlin.de 78and the high-performance com driver by 79.An Bruce Evans Aq Mt bde@kralizec.zeta.org.au . 80.Pp 81This work was made possible through the donation of a Cyclom-8Y board by the 82manufacturer, Cyclades Corporation. 83However, neither Cyclades nor the author make any warranties regarding 84this software, nor guarantees of support. 85.Sh AUTHORS 86The driver was written by 87.An Andrew Herbert Aq Mt andrew@werple.apana.org.au . 88.Sh BUGS 89There is currently no BREAK handling - breaks are ignored. 90There is no support for bad-character reporting, except via PARMRK. 91The Cyclom-[48]Y boards do not listen to the RTS signal for receiver flow 92control. 93FIFO overruns are only logged when the termios IGNPAR setting is enabled. 94