tjh.dev
Linux kernel mirror (for testing)
git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
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linux
1# SPDX-License-Identifier: GPL-2.0
2#
3# The 8250/16550 serial drivers. You shouldn't be in this list unless
4# you somehow have an implicit or explicit dependency on SERIAL_8250.
5#
6
7config SERIAL_8250
8 tristate "8250/16550 and compatible serial support"
9 depends on !S390
10 select SERIAL_CORE
11 ---help---
12 This selects whether you want to include the driver for the standard
13 serial ports. The standard answer is Y. People who might say N
14 here are those that are setting up dedicated Ethernet WWW/FTP
15 servers, or users that have one of the various bus mice instead of a
16 serial mouse and don't intend to use their machine's standard serial
17 port for anything. (Note that the Cyclades multi serial port driver
18 does not need this driver built in for it to work.)
19
20 To compile this driver as a module, choose M here: the
21 module will be called 8250.
22 [WARNING: Do not compile this driver as a module if you are using
23 non-standard serial ports, since the configuration information will
24 be lost when the driver is unloaded. This limitation may be lifted
25 in the future.]
26
27 BTW1: If you have a mouseman serial mouse which is not recognized by
28 the X window system, try running gpm first.
29
30 BTW2: If you intend to use a software modem (also called Winmodem)
31 under Linux, forget it. These modems are crippled and require
32 proprietary drivers which are only available under Windows.
33
34 Most people will say Y or M here, so that they can use serial mice,
35 modems and similar devices connecting to the standard serial ports.
36
37config SERIAL_8250_DEPRECATED_OPTIONS
38 bool "Support 8250_core.* kernel options (DEPRECATED)"
39 depends on SERIAL_8250
40 default y
41 ---help---
42 In 3.7 we renamed 8250 to 8250_core by mistake, so now we have to
43 accept kernel parameters in both forms like 8250_core.nr_uarts=4 and
44 8250.nr_uarts=4. We now renamed the module back to 8250, but if
45 anybody noticed in 3.7 and changed their userspace we still have to
46 keep the 8250_core.* options around until they revert the changes
47 they already did.
48
49 If 8250 is built as a module, this adds 8250_core alias instead.
50
51 If you did not notice yet and/or you have userspace from pre-3.7, it
52 is safe (and recommended) to say N here.
53
54config SERIAL_8250_PNP
55 bool "8250/16550 PNP device support" if EXPERT
56 depends on SERIAL_8250 && PNP
57 default y
58 ---help---
59 This builds standard PNP serial support. You may be able to
60 disable this feature if you only need legacy serial support.
61
62config SERIAL_8250_FINTEK
63 bool "Support for Fintek F81216A LPC to 4 UART RS485 API"
64 depends on SERIAL_8250
65 ---help---
66 Selecting this option will add support for the RS485 capabilities
67 of the Fintek F81216A LPC to 4 UART.
68
69 If this option is not selected the device will be configured as a
70 standard 16550A serial port.
71
72 If unsure, say N.
73
74config SERIAL_8250_CONSOLE
75 bool "Console on 8250/16550 and compatible serial port"
76 depends on SERIAL_8250=y
77 select SERIAL_CORE_CONSOLE
78 select SERIAL_EARLYCON
79 ---help---
80 If you say Y here, it will be possible to use a serial port as the
81 system console (the system console is the device which receives all
82 kernel messages and warnings and which allows logins in single user
83 mode). This could be useful if some terminal or printer is connected
84 to that serial port.
85
86 Even if you say Y here, the currently visible virtual console
87 (/dev/tty0) will still be used as the system console by default, but
88 you can alter that using a kernel command line option such as
89 "console=ttyS1". (Try "man bootparam" or see the documentation of
90 your boot loader (grub or lilo or loadlin) about how to pass options
91 to the kernel at boot time.)
92
93 If you don't have a VGA card installed and you say Y here, the
94 kernel will automatically use the first serial line, /dev/ttyS0, as
95 system console.
96
97 You can set that using a kernel command line option such as
98 "console=uart8250,io,0x3f8,9600n8"
99 "console=uart8250,mmio,0xff5e0000,115200n8".
100 and it will switch to normal serial console when the corresponding
101 port is ready.
102 "earlycon=uart8250,io,0x3f8,9600n8"
103 "earlycon=uart8250,mmio,0xff5e0000,115200n8".
104 it will not only setup early console.
105
106 If unsure, say N.
107
108config SERIAL_8250_GSC
109 tristate
110 depends on SERIAL_8250 && GSC
111 default SERIAL_8250
112
113config SERIAL_8250_DMA
114 bool "DMA support for 16550 compatible UART controllers" if EXPERT
115 depends on SERIAL_8250 && DMADEVICES=y
116 default SERIAL_8250
117 help
118 This builds DMA support that can be used with 8250/16650
119 compatible UART controllers that support DMA signaling.
120
121config SERIAL_8250_PCI
122 tristate "8250/16550 PCI device support"
123 depends on SERIAL_8250 && PCI
124 default SERIAL_8250
125 help
126 This builds standard PCI serial support. You may be able to
127 disable this feature if you only need legacy serial support.
128 Saves about 9K.
129 Note that serial ports on NetMos 9835 Multi-I/O cards are handled
130 by the parport_serial driver, enabled with CONFIG_PARPORT_SERIAL.
131
132config SERIAL_8250_EXAR
133 tristate "8250/16550 Exar/Commtech PCI/PCIe device support"
134 depends on SERIAL_8250_PCI
135 default SERIAL_8250
136 help
137 This builds support for XR17C1xx, XR17V3xx and some Commtech
138 422x PCIe serial cards that are not covered by the more generic
139 SERIAL_8250_PCI option.
140
141config SERIAL_8250_HP300
142 tristate
143 depends on SERIAL_8250 && HP300
144 default SERIAL_8250
145
146config SERIAL_8250_CS
147 tristate "8250/16550 PCMCIA device support"
148 depends on PCMCIA && SERIAL_8250
149 ---help---
150 Say Y here to enable support for 16-bit PCMCIA serial devices,
151 including serial port cards, modems, and the modem functions of
152 multi-function Ethernet/modem cards. (PCMCIA- or PC-cards are
153 credit-card size devices often used with laptops.)
154
155 To compile this driver as a module, choose M here: the
156 module will be called serial_cs.
157
158 If unsure, say N.
159
160config SERIAL_8250_MEN_MCB
161 tristate "MEN MCB UART device support"
162 depends on MCB && SERIAL_8250
163 help
164 This enables support for FPGA based UARTs found on many MEN
165 boards. This driver enables support for the 16z025, 16z057
166 and 16z125 UARTs.
167
168 To compile this driver as a module, chose M here: the
169 module will be called 8250_men_mcb.
170
171
172config SERIAL_8250_NR_UARTS
173 int "Maximum number of 8250/16550 serial ports"
174 depends on SERIAL_8250
175 default "4"
176 help
177 Set this to the number of serial ports you want the driver
178 to support. This includes any ports discovered via ACPI or
179 PCI enumeration and any ports that may be added at run-time
180 via hot-plug, or any ISA multi-port serial cards.
181
182config SERIAL_8250_RUNTIME_UARTS
183 int "Number of 8250/16550 serial ports to register at runtime"
184 depends on SERIAL_8250
185 range 0 SERIAL_8250_NR_UARTS
186 default "4"
187 help
188 Set this to the maximum number of serial ports you want
189 the kernel to register at boot time. This can be overridden
190 with the module parameter "nr_uarts", or boot-time parameter
191 8250.nr_uarts
192
193config SERIAL_8250_EXTENDED
194 bool "Extended 8250/16550 serial driver options"
195 depends on SERIAL_8250
196 help
197 If you wish to use any non-standard features of the standard "dumb"
198 driver, say Y here. This includes HUB6 support, shared serial
199 interrupts, special multiport support, support for more than the
200 four COM 1/2/3/4 boards, etc.
201
202 Note that the answer to this question won't directly affect the
203 kernel: saying N will just cause the configurator to skip all
204 the questions about serial driver options. If unsure, say N.
205
206config SERIAL_8250_MANY_PORTS
207 bool "Support more than 4 legacy serial ports"
208 depends on SERIAL_8250_EXTENDED && !IA64
209 help
210 Say Y here if you have dumb serial boards other than the four
211 standard COM 1/2/3/4 ports. This may happen if you have an AST
212 FourPort, Accent Async, Boca (read the Boca mini-HOWTO, available
213 from <http://www.tldp.org/docs.html#howto>), or other custom
214 serial port hardware which acts similar to standard serial port
215 hardware. If you only use the standard COM 1/2/3/4 ports, you can
216 say N here to save some memory. You can also say Y if you have an
217 "intelligent" multiport card such as Cyclades, Digiboards, etc.
218
219#
220# Multi-port serial cards
221#
222
223config SERIAL_8250_FOURPORT
224 tristate "Support Fourport cards"
225 depends on SERIAL_8250 != n && ISA && SERIAL_8250_MANY_PORTS
226 help
227 Say Y here if you have an AST FourPort serial board.
228
229 To compile this driver as a module, choose M here: the module
230 will be called 8250_fourport.
231
232config SERIAL_8250_ACCENT
233 tristate "Support Accent cards"
234 depends on SERIAL_8250 != n && ISA && SERIAL_8250_MANY_PORTS
235 help
236 Say Y here if you have an Accent Async serial board.
237
238 To compile this driver as a module, choose M here: the module
239 will be called 8250_accent.
240
241config SERIAL_8250_ASPEED_VUART
242 tristate "Aspeed Virtual UART"
243 depends on SERIAL_8250
244 depends on OF
245 help
246 If you want to use the virtual UART (VUART) device on Aspeed
247 BMC platforms, enable this option. This enables the 16550A-
248 compatible device on the local LPC bus, giving a UART device
249 with no physical RS232 connections.
250
251config SERIAL_8250_BOCA
252 tristate "Support Boca cards"
253 depends on SERIAL_8250 != n && ISA && SERIAL_8250_MANY_PORTS
254 help
255 Say Y here if you have a Boca serial board. Please read the Boca
256 mini-HOWTO, available from <http://www.tldp.org/docs.html#howto>
257
258 To compile this driver as a module, choose M here: the module
259 will be called 8250_boca.
260
261config SERIAL_8250_EXAR_ST16C554
262 tristate "Support Exar ST16C554/554D Quad UART"
263 depends on SERIAL_8250 != n && ISA && SERIAL_8250_MANY_PORTS
264 help
265 The Uplogix Envoy TU301 uses this Exar Quad UART. If you are
266 tinkering with your Envoy TU301, or have a machine with this UART,
267 say Y here.
268
269 To compile this driver as a module, choose M here: the module
270 will be called 8250_exar_st16c554.
271
272config SERIAL_8250_HUB6
273 tristate "Support Hub6 cards"
274 depends on SERIAL_8250 != n && ISA && SERIAL_8250_MANY_PORTS
275 help
276 Say Y here if you have a HUB6 serial board.
277
278 To compile this driver as a module, choose M here: the module
279 will be called 8250_hub6.
280
281#
282# Misc. options/drivers.
283#
284
285config SERIAL_8250_SHARE_IRQ
286 bool "Support for sharing serial interrupts"
287 depends on SERIAL_8250_EXTENDED
288 help
289 Some serial boards have hardware support which allows multiple dumb
290 serial ports on the same board to share a single IRQ. To enable
291 support for this in the serial driver, say Y here.
292
293config SERIAL_8250_DETECT_IRQ
294 bool "Autodetect IRQ on standard ports (unsafe)"
295 depends on SERIAL_8250_EXTENDED
296 help
297 Say Y here if you want the kernel to try to guess which IRQ
298 to use for your serial port.
299
300 This is considered unsafe; it is far better to configure the IRQ in
301 a boot script using the setserial command.
302
303 If unsure, say N.
304
305config SERIAL_8250_RSA
306 bool "Support RSA serial ports"
307 depends on SERIAL_8250_EXTENDED
308 help
309 Say Y here if you have a IODATA RSA-DV II/S ISA card and
310 would like to use its >115kbps speeds.
311 You will need to provide module parameter "probe_rsa", or boot-time
312 parameter 8250.probe_rsa with I/O addresses of this card then.
313
314 If you don't have such card, or if unsure, say N.
315
316config SERIAL_8250_ACORN
317 tristate "Acorn expansion card serial port support"
318 depends on ARCH_ACORN && SERIAL_8250
319 help
320 If you have an Atomwide Serial card or Serial Port card for an Acorn
321 system, say Y to this option. The driver can handle 1, 2, or 3 port
322 cards. If unsure, say N.
323
324config SERIAL_8250_BCM2835AUX
325 tristate "BCM2835 auxiliar mini UART support"
326 depends on ARCH_BCM2835 || COMPILE_TEST
327 depends on SERIAL_8250 && SERIAL_8250_SHARE_IRQ
328 help
329 Support for the BCM2835 auxiliar mini UART.
330
331 Features and limitations of the UART are
332 Registers are similar to 16650 registers,
333 set bits in the control registers that are unsupported
334 are ignored and read back as 0
335 7/8 bit operation with 1 start and 1 stop bit
336 8 symbols deep fifo for rx and tx
337 SW controlled RTS and SW readable CTS
338 Clock rate derived from system clock
339 Uses 8 times oversampling (compared to 16 times for 16650)
340 Missing break detection (but break generation)
341 Missing framing error detection
342 Missing parity bit
343 Missing receive time-out interrupt
344 Missing DCD, DSR, DTR and RI signals
345
346 If unsure, say N.
347
348config SERIAL_8250_FSL
349 bool
350 depends on SERIAL_8250_CONSOLE
351 default PPC || ARM || ARM64
352
353config SERIAL_8250_DW
354 tristate "Support for Synopsys DesignWare 8250 quirks"
355 depends on SERIAL_8250
356 help
357 Selecting this option will enable handling of the extra features
358 present in the Synopsys DesignWare APB UART.
359
360config SERIAL_8250_EM
361 tristate "Support for Emma Mobile integrated serial port"
362 depends on SERIAL_8250 && ARM && HAVE_CLK
363 help
364 Selecting this option will add support for the integrated serial
365 port hardware found on the Emma Mobile line of processors.
366 If unsure, say N.
367
368config SERIAL_8250_RT288X
369 bool "Ralink RT288x/RT305x/RT3662/RT3883 serial port support"
370 depends on SERIAL_8250
371 default y if MIPS_ALCHEMY || SOC_RT288X || SOC_RT305X || SOC_RT3883 || SOC_MT7620
372 help
373 Selecting this option will add support for the alternate register
374 layout used by Ralink RT288x/RT305x, Alchemy Au1xxx, and some others.
375 If unsure, say N.
376
377config SERIAL_8250_OMAP
378 tristate "Support for OMAP internal UART (8250 based driver)"
379 depends on SERIAL_8250 && (ARCH_OMAP2PLUS || ARCH_K3)
380 help
381 If you have a machine based on an Texas Instruments OMAP CPU you
382 can enable its onboard serial ports by enabling this option.
383
384 This driver uses ttyS instead of ttyO.
385
386config SERIAL_8250_OMAP_TTYO_FIXUP
387 bool "Replace ttyO with ttyS"
388 depends on SERIAL_8250_OMAP=y && SERIAL_8250_CONSOLE
389 default y
390 help
391 This option replaces the "console=ttyO" argument with the matching
392 ttyS argument if the user did not specified it on the command line.
393 This ensures that the user can see the kernel output during boot
394 which he wouldn't see otherwise. The getty has still to be configured
395 for ttyS instead of ttyO regardless of this option.
396 This option is intended for people who "automatically" enable this
397 driver without knowing that this driver requires a different console=
398 argument. If you read this, please keep this option disabled and
399 instead update your kernel command line. If you prepare a kernel for a
400 distribution or other kind of larger user base then you probably want
401 to keep this option enabled. Otherwise people might complain about a
402 not booting kernel because the serial console remains silent in case
403 they forgot to update the command line.
404
405config SERIAL_8250_LPC18XX
406 tristate "NXP LPC18xx/43xx serial port support"
407 depends on SERIAL_8250 && OF && (ARCH_LPC18XX || COMPILE_TEST)
408 default ARCH_LPC18XX
409 help
410 If you have a LPC18xx/43xx based board and want to use the
411 serial port, say Y to this option. If unsure, say Y.
412
413config SERIAL_8250_MT6577
414 tristate "Mediatek serial port support"
415 depends on SERIAL_8250 && ARCH_MEDIATEK
416 help
417 If you have a Mediatek based board and want to use the
418 serial port, say Y to this option. If unsure, say N.
419
420config SERIAL_8250_UNIPHIER
421 tristate "Support for UniPhier on-chip UART"
422 depends on SERIAL_8250
423 depends on ARCH_UNIPHIER || COMPILE_TEST
424 help
425 If you have a UniPhier based board and want to use the on-chip
426 serial ports, say Y to this option. If unsure, say N.
427
428config SERIAL_8250_INGENIC
429 tristate "Support for Ingenic SoC serial ports"
430 depends on SERIAL_8250
431 depends on OF_FLATTREE
432 depends on MIPS || COMPILE_TEST
433 help
434 If you have a system using an Ingenic SoC and wish to make use of
435 its UARTs, say Y to this option. If unsure, say N.
436
437config SERIAL_8250_LPSS
438 tristate "Support for serial ports on Intel LPSS platforms"
439 default SERIAL_8250
440 depends on SERIAL_8250 && PCI
441 depends on X86 || COMPILE_TEST
442 select DW_DMAC_CORE if SERIAL_8250_DMA
443 select DW_DMAC_PCI if (SERIAL_8250_DMA && X86_INTEL_LPSS)
444 select RATIONAL
445 help
446 Selecting this option will enable handling of the extra features
447 present on the UART found on various Intel platforms such as:
448 - Intel Baytrail SoC
449 - Intel Braswell SoC
450 - Intel Quark X1000 SoC
451
452config SERIAL_8250_MID
453 tristate "Support for serial ports on Intel MID platforms"
454 default SERIAL_8250
455 depends on SERIAL_8250 && PCI
456 depends on X86 || COMPILE_TEST
457 select HSU_DMA if SERIAL_8250_DMA
458 select HSU_DMA_PCI if (HSU_DMA && X86_INTEL_MID)
459 select RATIONAL
460 help
461 Selecting this option will enable handling of the extra features
462 present on the UART found on Intel Medfield SOC and various other
463 Intel platforms.
464
465config SERIAL_8250_MOXA
466 tristate "MOXA SmartIO MUE support"
467 depends on SERIAL_8250 && PCI
468 help
469 Say Y here if you have a Moxa SmartIO MUE multiport serial card.
470 If unsure, say N.
471
472 This driver can also be built as a module. The module will be called
473 8250_moxa. If you want to do that, say M here.
474
475config SERIAL_8250_PXA
476 tristate "PXA serial port support"
477 depends on SERIAL_8250
478 depends on ARCH_PXA || ARCH_MMP
479 help
480 If you have a machine based on an Intel XScale PXA2xx CPU you can
481 enable its onboard serial ports by enabling this option. The option is
482 applicable to both devicetree and legacy boards, and early console is
483 part of its support.
484
485config SERIAL_OF_PLATFORM
486 tristate "Devicetree based probing for 8250 ports"
487 depends on SERIAL_8250 && OF
488 help
489 This option is used for all 8250 compatible serial ports that
490 are probed through devicetree, including Open Firmware based
491 PowerPC systems and embedded systems on architectures using the
492 flattened device tree format.