1 .\" Copyright (c) 1990, 1991 The Regents of the University of California.
2 .\" All rights reserved.
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.
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17 .\" This product includes software developed by the University of
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35 .\" from: @(#)dca.4 5.2 (Berkeley) 3/27/91
36 .\" from: com.4,v 1.1 1993/08/06 11:19:07 cgd Exp
44 .Nd "fast interrupt driven asynchronous serial communications interface"
46 For standard ISA ports:
47 .Bd -ragged -offset indent -compact
51 .Pa /boot/device.hints :
52 .Cd hint.sio.0.at="isa"
53 .Cd hint.sio.0.port="0x3f8"
54 .Cd hint.sio.0.flags="0x10"
55 .Cd hint.sio.0.irq="4"
56 .Cd hint.sio.1.at="isa"
57 .Cd hint.sio.1.port="0x2f8"
58 .Cd hint.sio.1.flags="0x0"
59 .Cd hint.sio.1.irq="3"
62 For AST compatible multiport cards with 4 ports:
63 .Bd -ragged -offset indent -compact
64 .Cd "options COM_MULTIPORT"
68 .Pa /boot/device.hints :
69 .Cd hint.sio.4.at="isa"
70 .Cd hint.sio.4.port="0x2a0"
71 .Cd hint.sio.4.flags="0x701"
72 .Cd hint.sio.5.at="isa"
73 .Cd hint.sio.5.port="0x2a8"
74 .Cd hint.sio.5.flags="0x701"
75 .Cd hint.sio.6.at="isa"
76 .Cd hint.sio.6.port="0x2b0"
77 .Cd hint.sio.6.flags="0x701"
78 .Cd hint.sio.7.at="isa"
79 .Cd hint.sio.7.port="0x2b8"
80 .Cd hint.sio.7.flags="0x701"
81 .Cd hint.sio.7.irq="12"
84 For Boca Board compatible multiport cards with 8 ports:
85 .Bd -ragged -offset indent -compact
86 .Cd "options COM_MULTIPORT"
90 .Pa /boot/device.hints :
91 .Cd hint.sio.4.at="isa"
92 .Cd hint.sio.4.port="0x100"
93 .Cd hint.sio.4.flags="0xb05"
95 .Cd hint.sio.11.at="isa"
96 .Cd hint.sio.11.port="0x138"
97 .Cd hint.sio.11.flags="0xb05"
98 .Cd hint.sio.11.irq="12"
101 For Netmos Nm9845 multiport cards with 6 ports:
102 .Bd -ragged -offset indent -compact
103 .Cd "options COM_MULTIPORT"
107 .Pa /boot/device.hints :
108 .Cd hint.sio.4.at="isa"
109 .Cd hint.sio.4.port="0xb000"
110 .Cd hint.sio.4.flags="0x901"
111 .Cd hint.sio.5.at="isa"
112 .Cd hint.sio.5.port="0xb400"
113 .Cd hint.sio.5.flags="0x901"
114 .Cd hint.sio.6.at="isa"
115 .Cd hint.sio.6.port="0xb800"
116 .Cd hint.sio.6.flags="0x901"
117 .Cd hint.sio.7.at="isa"
118 .Cd hint.sio.7.port="0xbc00"
119 .Cd hint.sio.7.flags="0x901"
120 .Cd hint.sio.8.at="isa"
121 .Cd hint.sio.8.port="0xc000"
122 .Cd hint.sio.8.flags="0x901"
123 .Cd hint.sio.9.at="isa"
124 .Cd hint.sio.9.port="0xac00"
125 .Cd hint.sio.9.flags="0x901"
126 .Cd hint.sio.9.irq="12"
130 .Bd -ragged -offset indent -compact
131 .Cd "options COM_ESP"
136 For single port PCI and PCCARD cards:
137 .Bd -ragged -offset indent -compact
140 No lines are required in
141 .Pa /boot/device.hints
145 For dual port PCI cards that share an interrupt:
146 .Bd -ragged -offset indent -compact
148 .Cd "options COM_MULTIPORT"
151 .Pa /boot/device.hints :
152 .Cd hint.sio.2.flags="0x201"
153 .Cd hint.sio.3.flags="0x201"
158 .Bl -tag -offset indent -compact -width 0x000000
164 no AST/4 compatible IRQ control register
166 recover sooner from lost output interrupts
168 device is potential system console
170 device is forced to become system console
172 device is reserved for low-level IO (e.g.\& for remote kernel debugging)
174 use this port for remote kernel debugging
175 .It 0x0 Ns Em ?? Ns 00
176 minor number of master port
178 PPS timestamping on CTS instead of DCD
180 device is assumed to use a 16650A-type (extended FIFO) chip
184 .Bd -literal -offset indent -compact
194 driver provides support for NS8250-, NS16450-, NS16550 and NS16550A-based
199 communications interfaces.
200 The NS8250 and NS16450 have single character
201 buffers, the NS16550A has 16 character FIFO input and output buffers.
203 Input and output for each line may set to one of following baud rates;
204 50, 75, 110, 134.5, 150, 300, 600, 1200, 1800, 2400, 4800, 9600,
205 19200, 28800, 38400, 57600, or 115200.
206 Your hardware may limit your baud rate choices.
208 The driver supports `multiport' cards.
209 Multiport cards are those that have one or more groups of ports
210 that share an Interrupt Request (IRQ) line per group.
211 Shared IRQs on different cards are not supported.
212 Frequently 4 ports share 1 IRQ; some 8 port cards have 2 groups of 4 ports,
214 Some cards allow the first 2 serial ports to have separate IRQs per port
215 (as per DOS PC standard).
217 Some cards have an IRQ control register for each group.
218 Some cards require special initialization related to such registers.
219 Only AST/4 compatible IRQ control registers are supported.
220 Some cards have an IRQ status register for each group.
221 The driver does not require or use such registers yet.
222 To work, the control and status registers for a group, if any,
223 must be mapped to the scratch register (register 7)
224 of a port in the group.
225 Such a port is called a
229 The driver supports controller based PCI modems.
230 The 3Com FaxModem PCI and the Advantec 56k Voice Messaging PCI
231 FaxModem are the only cards supported.
232 WinModems, softmodems, hfc modems and any other modems that aren't
233 controller based are not supported.
237 keyword may be used on each
239 line in the kernel configuration file
240 to disable the FIFO on 16550A UARTs
242 Disabling the FIFO should rarely be necessary.
248 be used for all ports that are part of an IRQ sharing group.
249 One bit specifies IRQ sharing; another bit specifies whether the port does
251 require AST/4 compatible initialization.
252 The minor number of the device corresponding a master port
253 for the group is encoded as a bitfield in the high byte.
254 The same master port must be specified for all ports in a group.
258 specification must be given for master ports
259 and for ports that are not part of an IRQ sharing group,
260 and not for other ports.
264 means that the 8th port (sio7) is the master
265 port, and that the port is on a multiport card with shared IRQs
266 and an AST/4 compatible IRQ control register.
269 means that the 12th port (sio11) is the master
270 port, and that the port is on a multiport card with shared IRQs
271 and no special IRQ control register.
273 Which port is the master port depends on the card type.
274 Consult the hardware documentation of your card.
275 Since IRQ status registers are never used,
276 and IRQ control registers are only used for AST/4 compatible cards,
277 and some cards map the control/status registers to all ports in a group,
278 any port in a group will sometimes do for the master port.
279 Choose a port containing an IRQ status register for forwards compatibility,
280 and the highest possible port for consistency.
282 Serial ports controlled by the
284 driver can be used for both `callin' and `callout'.
285 For each port there is a callin device and a callout device.
286 The minor number of the callout device is 128 higher
287 than that of the corresponding callin port.
288 The callin device is general purpose.
289 Processes opening it normally wait for carrier
290 and for the callout device to become inactive.
291 The callout device is used to steal the port from
292 processes waiting for carrier on the callin device.
293 Processes opening it do not wait for carrier
294 and put any processes waiting for carrier on the callin device into
295 a deeper sleep so that they do not conflict with the callout session.
296 The callout device is abused for handling programs that are supposed
297 to work on general ports and need to open the port without waiting
298 but are too stupid to do so.
302 driver also supports an initial-state and a lock-state control
303 device for each of the callin and the callout "data" devices.
304 The minor number of the initial-state device is 32 higher
305 than that of the corresponding data device.
306 The minor number of the lock-state device is 64 higher
307 than that of the corresponding data device.
308 The termios settings of a data device are copied
309 from those of the corresponding initial-state device
310 on first opens and are not inherited from previous opens.
313 in the normal way on the initial-state devices to program
314 initial termios states suitable for your setup.
316 The lock termios state acts as flags to disable changing
318 E.g., to lock a flag variable such as CRTSCTS, use
320 on the lock-state device.
321 Speeds and special characters
322 may be locked by setting the corresponding value in the lock-state
323 device to any nonzero value.
325 Correct programs talking to correctly wired external devices
326 work with almost arbitrary initial states and almost no locking,
327 but other setups may benefit from changing some of the default
328 initial state and locking the state.
329 In particular, the initial states for non (POSIX) standard flags
330 should be set to suit the devices attached and may need to be
331 locked to prevent buggy programs from changing them.
332 E.g., CRTSCTS should be locked on for devices that support
333 RTS/CTS handshaking at all times and off for devices that don't
335 CLOCAL should be locked on for devices that don't support carrier.
336 HUPCL may be locked off if you don't
337 want to hang up for some reason.
338 In general, very bad things happen
339 if something is locked to the wrong state, and things should not
340 be locked for devices that support more than one setting.
341 The CLOCAL flag on callin ports should be locked off for logins
342 to avoid certain security holes, but this needs to be done by
343 getty if the callin port is used for anything else.
345 .Bl -tag -width /dev/ttyid? -compact
350 corresponding callin initial-state and lock-state devices
356 corresponding callout initial-state and lock-state devices
359 .Bl -tag -width /etc/rc.serial -compact
360 .It Pa /etc/rc.serial
361 examples of setting the initial-state and lock-state devices
364 The device numbers are made from the set [0-9a-v] so that more than
365 10 ports can be supported.
368 .It sio%d: silo overflow.
369 Problem in the interrupt handler.
372 .It sio%d: interrupt-level buffer overflow.
373 Problem in the bottom half of the driver.
376 .It sio%d: tty-level buffer overflow.
377 Problem in the application.
378 Input has arrived faster than the given module could process it
379 and some has been lost.
382 .\" .It sio%d: reduced fifo trigger level to %d.
383 .\" Attempting to avoid further silo overflows.
393 driver is derived from the
399 Data loss may occur at very high baud rates on slow systems,
400 or with too many ports on any system,
401 or on heavily loaded systems when crtscts cannot be used.
402 The use of NS16550A's reduces system load and helps to avoid data loss.
404 Stay away from plain NS16550's.
405 These are early implementations of the chip with non-functional FIFO hardware.
407 The constants which define the locations
408 of the various serial ports are holdovers from
410 As shown, hex addresses can be and for clarity probably should be used instead.
412 Note that on the AST/4 the card's dipswitches should
414 be set to use interrupt sharing.
415 AST/4-like interrupt sharing is only used when
417 AST/4 cards are installed in the same system.
420 driver does not support more than 1 AST/4 on one IRQ.
422 The examples in the synopsis are too vendor-specific.