1.\" Copyright (c) 1990, 1991 The Regents of the University of California. 2.\" All rights reserved. 3.\" 4.\" This code is derived from software contributed to Berkeley by 5.\" the Systems Programming Group of the University of Utah Computer 6.\" Science Department. 7.\" Redistribution and use in source and binary forms, with or without 8.\" modification, are permitted provided that the following conditions 9.\" are met: 10.\" 1. Redistributions of source code must retain the above copyright 11.\" notice, this list of conditions and the following disclaimer. 12.\" 2. Redistributions in binary form must reproduce the above copyright 13.\" notice, this list of conditions and the following disclaimer in the 14.\" documentation and/or other materials provided with the distribution. 15.\" 3. Neither the name of the University nor the names of its contributors 16.\" may be used to endorse or promote products derived from this software 17.\" without specific prior written permission. 18.\" 19.\" THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 20.\" ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 21.\" IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 22.\" ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 23.\" FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 24.\" DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 25.\" OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 26.\" HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 27.\" LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 28.\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 29.\" SUCH DAMAGE. 30.\" 31.\" from: @(#)dca.4 5.2 (Berkeley) 3/27/91 32.\" from: com.4,v 1.1 1993/08/06 11:19:07 cgd Exp 33.\" $FreeBSD: src/share/man/man4/sio.4,v 1.34.2.4 2002/12/18 13:31:17 keramida Exp $ 34.\" $DragonFly: src/share/man/man4/sio.4,v 1.3 2007/12/16 02:55:38 thomas Exp $ 35.\" 36.Dd October 10, 1995 37.Dt SIO 4 38.Os 39.Sh NAME 40.Nm sio 41.Nd "fast interrupt driven asynchronous serial communications interface" 42.Sh SYNOPSIS 43For standard ports: 44.Cd "device sio0 at isa? port IO_COM1 irq 4" 45.Cd "device sio1 at isa? port IO_COM2 irq 3" 46.Cd "device sio2 at isa? port IO_COM3 irq 5" 47.Cd "device sio3 at isa? port IO_COM4 irq 9" 48.Pp 49For AST compatible multiport cards with 4 ports: 50.Cd "options COM_MULTIPORT" 51.Cd "device sio4 at isa? port 0x2a0 flags 0x701" 52.Cd "device sio5 at isa? port 0x2a8 flags 0x701" 53.Cd "device sio6 at isa? port 0x2b0 flags 0x701" 54.Cd "device sio7 at isa? port 0x2b8 flags 0x701 irq 12" 55.Pp 56For Boca Board compatible multiport cards with 8 ports: 57.Cd "options COM_MULTIPORT" 58.Cd "device sio4 at isa? port 0x100 flags 0xb05" 59.Cd "..." 60.Cd "device sio11 at isa? port 0x138 flags 0xb05 irq 12" 61.Pp 62For Netmos Nm9845 multiport cards with 6 ports: 63.Cd "options COM_MULTIPORT" 64.Cd "device sio4 at isa? port 0xb000 flags 0x901" 65.Cd "device sio5 at isa? port 0xb400 flags 0x901" 66.Cd "device sio6 at isa? port 0xb800 flags 0x901" 67.Cd "device sio7 at isa? port 0xbc00 flags 0x901" 68.Cd "device sio8 at isa? port 0xc000 flags 0x901" 69.Cd "device sio9 at isa? port 0xac00 flags 0x901 irq 12" 70.Pp 71For Hayes ESP cards: 72.Cd "options COM_ESP" 73.Cd "..." 74.Pp 75Meaning of 76.Ar flags : 77.Bl -tag -offset indent -compact -width 0x000000 78.It 0x00001 79shared IRQs 80.It 0x00002 81disable FIFO 82.It 0x00004 83no AST/4 compatible IRQ control register 84.It 0x00008 85recover sooner from lost output interrupts 86.It 0x00010 87device is potential system console 88.It 0x00020 89device is forced to become system console 90.It 0x00040 91device is reserved for low-level IO (e. g. for remote kernel debugging) 92.It 0x00080 93use this port for remote kernel debugging 94.It 0x0 Ns Em ?? Ns 00 95minor number of master port 96.It 0x20000 97device is assumed to use a 16650A-type (extended FIFO) chip 98.El 99.Pp 100Minor numbering: 101.Bd -literal 1020b\fIOLIMMMMM\fR 103 call\fBO\fRut 104 \fBL\fRock 105 \fBI\fRnitial 106 \fBMMMMM\fRinor 107.Ed 108.Sh DESCRIPTION 109The 110.Nm 111driver provides support for NS8250-, NS16450-, NS16550 and NS16550A-based 112.Tn EIA 113.Tn RS-232C 114.Pf ( Tn CCITT 115.Tn V.24 ) 116communications interfaces. The NS8250 and NS16450 have single character 117buffers, the NS16550A has 16 character FIFO input and output buffers. 118.Pp 119Input and output for each line may set to one of following baud rates; 12050, 75, 110, 134.5, 150, 300, 600, 1200, 1800, 2400, 4800, 9600, 12119200, 38400, 57600, or 115200. Your hardware may limit your baud 122rate choices. 123.Pp 124The driver supports `multiport' cards. 125Multiport cards are those that have one or more groups of ports 126that share an Interrupt Request (IRQ) line per group. 127Shared IRQs on different cards are not supported. 128Frequently 4 ports share 1 IRQ; some 8 port cards have 2 groups of 4 ports, 129thus using 2 IRQs. 130Some cards allow the first 2 serial ports to have separate IRQs per port 131(as per DOS PC standard). 132.Pp 133Some cards have an IRQ control register for each group. 134Some cards require special initialization related to such registers. 135Only AST/4 compatible IRQ control registers are supported. 136Some cards have an IRQ status register for each group. 137The driver does not require or use such registers yet. 138To work, the control and status registers for a group, if any, 139must be mapped to the scratch register (register 7) 140of a port in the group. 141Such a port is called a 142.Em master 143port. 144.Pp 145The 146.Em flags 147keyword may be used on each 148.Em device sio 149line in the kernel configuration file 150to disable the FIFO on 16550A UARTs 151(see the synopsis). 152Disabling the FIFO should rarely be necessary. 153.Pp 154The 155.Em flags 156keyword 157.Em must 158be used for all ports that are part of an IRQ sharing group. 159One bit specifies IRQ sharing; another bit specifies whether the port does 160.Em not 161require AST/4 compatible initialization. 162The minor number of the device corresponding a master port 163for the group is encoded as a bitfield in the high byte. 164The same master port must be specified for all ports in a group. 165.Pp 166The 167.Em irq 168specification must be given for master ports 169and for ports that are not part of an IRQ sharing group, 170and not for other ports. 171.Pp 172In the synopsis, 173.Em flags 0x701 174means that the 8th port (sio7) is the master 175port, and that the port is on a multiport card with shared IRQs 176and an AST/4 compatible IRQ control register. 177.Pp 178.Em flags 0xb05 179means that the 12th port (sio11) is the master 180port, and that the port is on a multiport card with shared IRQs 181and no special IRQ control register. 182.Pp 183Which port is the master port depends on the card type. 184Consult the hardware documentation of your card. 185Since IRQ status registers are never used, 186and IRQ control registers are only used for AST/4 compatible cards, 187and some cards map the control/status registers to all ports in a group, 188any port in a group will sometimes do for the master port. 189Choose a port containing an IRQ status register for forwards compatibility, 190and the highest possible port for consistency. 191.Pp 192Serial ports controlled by the 193.Nm 194driver can be used for both `callin' and `callout'. 195For each port there is a callin device and a callout device. 196The minor number of the callout device is 128 higher 197than that of the corresponding callin port. 198The callin device is general purpose. 199Processes opening it normally wait for carrier 200and for the callout device to become inactive. 201The callout device is used to steal the port from 202processes waiting for carrier on the callin device. 203Processes opening it do not wait for carrier 204and put any processes waiting for carrier on the callin device into 205a deeper sleep so that they do not conflict with the callout session. 206The callout device is abused for handling programs that are supposed 207to work on general ports and need to open the port without waiting 208but are too stupid to do so. 209.Pp 210The 211.Nm 212driver also supports an initial-state and a lock-state control 213device for each of the callin and the callout "data" devices. 214The minor number of the initial-state device is 32 higher 215than that of the corresponding data device. 216The minor number of the lock-state device is 64 higher 217than that of the corresponding data device. 218The termios settings of a data device are copied 219from those of the corresponding initial-state device 220on first opens and are not inherited from previous opens. 221Use 222.Xr stty 1 223in the normal way on the initial-state devices to program 224initial termios states suitable for your setup. 225.Pp 226The lock termios state acts as flags to disable changing 227the termios state. E.g., to lock a flag variable such as 228CRTSCTS, use 229.Em stty crtscts 230on the lock-state device. Speeds and special characters 231may be locked by setting the corresponding value in the lock-state 232device to any nonzero value. 233.Pp 234Correct programs talking to correctly wired external devices 235work with almost arbitrary initial states and almost no locking, 236but other setups may benefit from changing some of the default 237initial state and locking the state. 238In particular, the initial states for non (POSIX) standard flags 239should be set to suit the devices attached and may need to be 240locked to prevent buggy programs from changing them. 241E.g., CRTSCTS should be locked on for devices that support 242RTS/CTS handshaking at all times and off for devices that don't 243support it at all. CLOCAL should be locked on for devices 244that don't support carrier. HUPCL may be locked off if you don't 245want to hang up for some reason. In general, very bad things happen 246if something is locked to the wrong state, and things should not 247be locked for devices that support more than one setting. The 248CLOCAL flag on callin ports should be locked off for logins 249to avoid certain security holes, but this needs to be done by 250getty if the callin port is used for anything else. 251.Sh FILES 252.Bl -tag -width /dev/ttyid? -compact 253.It Pa /dev/ttyd? 254for callin ports 255.It Pa /dev/ttyid? 256.It Pa /dev/ttyld? 257corresponding callin initial-state and lock-state devices 258.Pp 259.It Pa /dev/cuaa? 260for callout ports 261.It Pa /dev/cuaia? 262.It Pa /dev/cuala? 263corresponding callout initial-state and lock-state devices 264.El 265.Pp 266.Bl -tag -width /etc/rc.d/serial -compact 267.It Pa /etc/rc.d/serial 268examples of setting the initial-state and lock-state devices 269.El 270.Pp 271The device numbers are made from the set [0-9a-v] so that more than 27210 ports can be supported. 273.Sh DIAGNOSTICS 274.Bl -diag 275.It sio%d: silo overflow. 276Problem in the interrupt handler. 277.El 278.Bl -diag 279.It sio%d: interrupt-level buffer overflow. 280Problem in the bottom half of the driver. 281.El 282.Bl -diag 283.It sio%d: tty-level buffer overflow. 284Problem in the application. 285Input has arrived faster than the given module could process it 286and some has been lost. 287.El 288.\" .Bl -diag 289.\" .It sio%d: reduced fifo trigger level to %d. 290.\" Attempting to avoid further silo overflows. 291.\" .El 292.Sh SEE ALSO 293.Xr stty 1 , 294.Xr termios 4 , 295.Xr tty 4 , 296.Xr comcontrol 8 297.Sh HISTORY 298The 299.Nm 300driver is derived from the 301.Tn HP9000/300 302.Xr dca 4 303driver and is 304.Ud 305.Sh BUGS 306Data loss may occur at very high baud rates on slow systems, 307or with too many ports on any system, 308or on heavily loaded systems when crtscts cannot be used. 309The use of NS16550A's reduces system load and helps to avoid data loss. 310.Pp 311Stay away from plain NS16550's. These are early 312implementations of the chip with non-functional FIFO hardware. 313.Pp 314The constants which define the locations 315of the various serial ports are holdovers from 316.Tn DOS . 317As shown, hex addresses can be and for clarity probably should be used instead. 318.Pp 319Note that on the AST/4 the card's dipswitches should 320.Em not 321be set to use interrupt sharing. 322AST/4-like interrupt sharing is only used when 323.Em multiple 324AST/4 cards are installed in the same system. The sio driver does not 325support more than 1 AST/4 on one IRQ. 326.Pp 327The examples in the synopsis are too vendor-specific. 328