xref: /openbmc/linux/drivers/tty/serial/8250/Kconfig (revision e15a5365)
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	select SERIAL_MCTRL_GPIO if GPIOLIB
12	help
13	  This selects whether you want to include the driver for the standard
14	  serial ports.  The standard answer is Y.  People who might say N
15	  here are those that are setting up dedicated Ethernet WWW/FTP
16	  servers, or users that have one of the various bus mice instead of a
17	  serial mouse and don't intend to use their machine's standard serial
18	  port for anything.  (Note that the Cyclades multi serial port driver
19	  does not need this driver built in for it to work.)
20
21	  To compile this driver as a module, choose M here: the
22	  module will be called 8250.
23	  [WARNING: Do not compile this driver as a module if you are using
24	  non-standard serial ports, since the configuration information will
25	  be lost when the driver is unloaded.  This limitation may be lifted
26	  in the future.]
27
28	  BTW1: If you have a mouseman serial mouse which is not recognized by
29	  the X window system, try running gpm first.
30
31	  BTW2: If you intend to use a software modem (also called Winmodem)
32	  under Linux, forget it.  These modems are crippled and require
33	  proprietary drivers which are only available under Windows.
34
35	  Most people will say Y or M here, so that they can use serial mice,
36	  modems and similar devices connecting to the standard serial ports.
37
38config SERIAL_8250_DEPRECATED_OPTIONS
39	bool "Support 8250_core.* kernel options (DEPRECATED)"
40	depends on SERIAL_8250
41	default y
42	help
43	  In 3.7 we renamed 8250 to 8250_core by mistake, so now we have to
44	  accept kernel parameters in both forms like 8250_core.nr_uarts=4 and
45	  8250.nr_uarts=4. We now renamed the module back to 8250, but if
46	  anybody noticed in 3.7 and changed their userspace we still have to
47	  keep the 8250_core.* options around until they revert the changes
48	  they already did.
49
50	  If 8250 is built as a module, this adds 8250_core alias instead.
51
52	  If you did not notice yet and/or you have userspace from pre-3.7, it
53	  is safe (and recommended) to say N here.
54
55config SERIAL_8250_PNP
56	bool "8250/16550 PNP device support" if EXPERT
57	depends on SERIAL_8250 && PNP
58	default y
59	help
60	  This builds standard PNP serial support. You may be able to
61	  disable this feature if you only need legacy serial support.
62
63config SERIAL_8250_16550A_VARIANTS
64	bool "Support for variants of the 16550A serial port"
65	depends on SERIAL_8250
66	default !X86
67	help
68	  The 8250 driver can probe for many variants of the venerable 16550A
69	  serial port. Doing so takes additional time at boot.
70
71	  On modern systems, especially those using serial only for a simple
72	  console, you can say N here.
73
74config SERIAL_8250_FINTEK
75	bool "Support for Fintek F81216A LPC to 4 UART RS485 API"
76	depends on SERIAL_8250
77	help
78	  Selecting this option will add support for the RS485 capabilities
79	  of the Fintek F81216A LPC to 4 UART.
80
81	  If this option is not selected the device will be configured as a
82	  standard 16550A serial port.
83
84	  If unsure, say N.
85
86config SERIAL_8250_CONSOLE
87	bool "Console on 8250/16550 and compatible serial port"
88	depends on SERIAL_8250=y
89	select SERIAL_CORE_CONSOLE
90	select SERIAL_EARLYCON
91	help
92	  If you say Y here, it will be possible to use a serial port as the
93	  system console (the system console is the device which receives all
94	  kernel messages and warnings and which allows logins in single user
95	  mode). This could be useful if some terminal or printer is connected
96	  to that serial port.
97
98	  Even if you say Y here, the currently visible virtual console
99	  (/dev/tty0) will still be used as the system console by default, but
100	  you can alter that using a kernel command line option such as
101	  "console=ttyS1". (Try "man bootparam" or see the documentation of
102	  your boot loader (grub or lilo or loadlin) about how to pass options
103	  to the kernel at boot time.)
104
105	  If you don't have a VGA card installed and you say Y here, the
106	  kernel will automatically use the first serial line, /dev/ttyS0, as
107	  system console.
108
109	  You can set that using a kernel command line option such as
110	  "console=uart8250,io,0x3f8,9600n8"
111	  "console=uart8250,mmio,0xff5e0000,115200n8".
112	  and it will switch to normal serial console when the corresponding
113	  port is ready.
114	  "earlycon=uart8250,io,0x3f8,9600n8"
115	  "earlycon=uart8250,mmio,0xff5e0000,115200n8".
116	  it will not only setup early console.
117
118	  If unsure, say N.
119
120config SERIAL_8250_GSC
121	tristate
122	depends on SERIAL_8250 && GSC
123	default SERIAL_8250
124
125config SERIAL_8250_DMA
126	bool "DMA support for 16550 compatible UART controllers" if EXPERT
127	depends on SERIAL_8250 && DMADEVICES=y
128	default SERIAL_8250
129	help
130	  This builds DMA support that can be used with 8250/16650
131	  compatible UART controllers that support DMA signaling.
132
133config SERIAL_8250_PCI
134	tristate "8250/16550 PCI device support"
135	depends on SERIAL_8250 && PCI
136	default SERIAL_8250
137	help
138	  This builds standard PCI serial support. You may be able to
139	  disable this feature if you only need legacy serial support.
140	  Saves about 9K.
141	  Note that serial ports on NetMos 9835 Multi-I/O cards are handled
142	  by the parport_serial driver, enabled with CONFIG_PARPORT_SERIAL.
143
144config SERIAL_8250_EXAR
145	tristate "8250/16550 Exar/Commtech PCI/PCIe device support"
146	depends on SERIAL_8250_PCI
147	default SERIAL_8250
148	help
149	  This builds support for XR17C1xx, XR17V3xx and some Commtech
150	  422x PCIe serial cards that are not covered by the more generic
151	  SERIAL_8250_PCI option.
152
153config SERIAL_8250_HP300
154	tristate
155	depends on SERIAL_8250 && HP300
156	default SERIAL_8250
157
158config SERIAL_8250_CS
159	tristate "8250/16550 PCMCIA device support"
160	depends on PCMCIA && SERIAL_8250
161	help
162	  Say Y here to enable support for 16-bit PCMCIA serial devices,
163	  including serial port cards, modems, and the modem functions of
164	  multi-function Ethernet/modem cards. (PCMCIA- or PC-cards are
165	  credit-card size devices often used with laptops.)
166
167	  To compile this driver as a module, choose M here: the
168	  module will be called serial_cs.
169
170	  If unsure, say N.
171
172config SERIAL_8250_MEN_MCB
173	tristate "MEN MCB UART device support"
174	depends on MCB && SERIAL_8250
175	help
176	  This enables support for FPGA based UARTs found on many MEN
177	  boards. This driver enables support for the 16z025, 16z057
178	  and 16z125 UARTs.
179
180	  To compile this driver as a module, chose M here: the
181	  module will be called 8250_men_mcb.
182
183
184config SERIAL_8250_NR_UARTS
185	int "Maximum number of 8250/16550 serial ports"
186	depends on SERIAL_8250
187	default "4"
188	help
189	  Set this to the number of serial ports you want the driver
190	  to support.  This includes any ports discovered via ACPI or
191	  PCI enumeration and any ports that may be added at run-time
192	  via hot-plug, or any ISA multi-port serial cards.
193
194config SERIAL_8250_RUNTIME_UARTS
195	int "Number of 8250/16550 serial ports to register at runtime"
196	depends on SERIAL_8250
197	range 0 SERIAL_8250_NR_UARTS
198	default "4"
199	help
200	  Set this to the maximum number of serial ports you want
201	  the kernel to register at boot time.  This can be overridden
202	  with the module parameter "nr_uarts", or boot-time parameter
203	  8250.nr_uarts
204
205config SERIAL_8250_EXTENDED
206	bool "Extended 8250/16550 serial driver options"
207	depends on SERIAL_8250
208	help
209	  If you wish to use any non-standard features of the standard "dumb"
210	  driver, say Y here. This includes HUB6 support, shared serial
211	  interrupts, special multiport support, support for more than the
212	  four COM 1/2/3/4 boards, etc.
213
214	  Note that the answer to this question won't directly affect the
215	  kernel: saying N will just cause the configurator to skip all
216	  the questions about serial driver options. If unsure, say N.
217
218config SERIAL_8250_MANY_PORTS
219	bool "Support more than 4 legacy serial ports"
220	depends on SERIAL_8250_EXTENDED && !IA64
221	help
222	  Say Y here if you have dumb serial boards other than the four
223	  standard COM 1/2/3/4 ports. This may happen if you have an AST
224	  FourPort, Accent Async, Boca (read the Boca mini-HOWTO, available
225	  from <https://www.tldp.org/docs.html#howto>), or other custom
226	  serial port hardware which acts similar to standard serial port
227	  hardware. If you only use the standard COM 1/2/3/4 ports, you can
228	  say N here to save some memory. You can also say Y if you have an
229	  "intelligent" multiport card such as Cyclades, Digiboards, etc.
230
231#
232# Multi-port serial cards
233#
234
235config SERIAL_8250_FOURPORT
236	tristate "Support Fourport cards"
237	depends on SERIAL_8250 != n && ISA && SERIAL_8250_MANY_PORTS
238	help
239	  Say Y here if you have an AST FourPort serial board.
240
241	  To compile this driver as a module, choose M here: the module
242	  will be called 8250_fourport.
243
244config SERIAL_8250_ACCENT
245	tristate "Support Accent cards"
246	depends on SERIAL_8250 != n && ISA && SERIAL_8250_MANY_PORTS
247	help
248	  Say Y here if you have an Accent Async serial board.
249
250	  To compile this driver as a module, choose M here: the module
251	  will be called 8250_accent.
252
253config SERIAL_8250_ASPEED_VUART
254	tristate "Aspeed Virtual UART"
255	depends on SERIAL_8250
256	depends on OF
257	depends on REGMAP && MFD_SYSCON
258	help
259	  If you want to use the virtual UART (VUART) device on Aspeed
260	  BMC platforms, enable this option. This enables the 16550A-
261	  compatible device on the local LPC bus, giving a UART device
262	  with no physical RS232 connections.
263
264config SERIAL_8250_BOCA
265	tristate "Support Boca cards"
266	depends on SERIAL_8250 != n && ISA && SERIAL_8250_MANY_PORTS
267	help
268	  Say Y here if you have a Boca serial board.  Please read the Boca
269	  mini-HOWTO, available from <https://www.tldp.org/docs.html#howto>
270
271	  To compile this driver as a module, choose M here: the module
272	  will be called 8250_boca.
273
274config SERIAL_8250_EXAR_ST16C554
275	tristate "Support Exar ST16C554/554D Quad UART"
276	depends on SERIAL_8250 != n && ISA && SERIAL_8250_MANY_PORTS
277	help
278	  The Uplogix Envoy TU301 uses this Exar Quad UART.  If you are
279	  tinkering with your Envoy TU301, or have a machine with this UART,
280	  say Y here.
281
282	  To compile this driver as a module, choose M here: the module
283	  will be called 8250_exar_st16c554.
284
285config SERIAL_8250_HUB6
286	tristate "Support Hub6 cards"
287	depends on SERIAL_8250 != n && ISA && SERIAL_8250_MANY_PORTS
288	help
289	  Say Y here if you have a HUB6 serial board.
290
291	  To compile this driver as a module, choose M here: the module
292	  will be called 8250_hub6.
293
294#
295# Misc. options/drivers.
296#
297
298config SERIAL_8250_SHARE_IRQ
299	bool "Support for sharing serial interrupts"
300	depends on SERIAL_8250_EXTENDED
301	help
302	  Some serial boards have hardware support which allows multiple dumb
303	  serial ports on the same board to share a single IRQ. To enable
304	  support for this in the serial driver, say Y here.
305
306config SERIAL_8250_DETECT_IRQ
307	bool "Autodetect IRQ on standard ports (unsafe)"
308	depends on SERIAL_8250_EXTENDED
309	help
310	  Say Y here if you want the kernel to try to guess which IRQ
311	  to use for your serial port.
312
313	  This is considered unsafe; it is far better to configure the IRQ in
314	  a boot script using the setserial command.
315
316	  If unsure, say N.
317
318config SERIAL_8250_RSA
319	bool "Support RSA serial ports"
320	depends on SERIAL_8250_EXTENDED
321	help
322	  Say Y here if you have a IODATA RSA-DV II/S ISA card and
323	  would like to use its >115kbps speeds.
324	  You will need to provide module parameter "probe_rsa", or boot-time
325	  parameter 8250.probe_rsa with I/O addresses of this card then.
326
327	  If you don't have such card, or if unsure, say N.
328
329config SERIAL_8250_DWLIB
330	bool
331
332config SERIAL_8250_ACORN
333	tristate "Acorn expansion card serial port support"
334	depends on ARCH_ACORN && SERIAL_8250
335	help
336	  If you have an Atomwide Serial card or Serial Port card for an Acorn
337	  system, say Y to this option.  The driver can handle 1, 2, or 3 port
338	  cards.  If unsure, say N.
339
340config SERIAL_8250_BCM2835AUX
341	tristate "BCM2835 auxiliar mini UART support"
342	depends on ARCH_BCM2835 || COMPILE_TEST
343	depends on SERIAL_8250 && SERIAL_8250_SHARE_IRQ
344	help
345	  Support for the BCM2835 auxiliar mini UART.
346
347	  Features and limitations of the UART are
348	    Registers are similar to 16650 registers,
349	      set bits in the control registers that are unsupported
350	      are ignored and read back as 0
351	    7/8 bit operation with 1 start and 1 stop bit
352	    8 symbols deep fifo for rx and tx
353	    SW controlled RTS and SW readable CTS
354	    Clock rate derived from system clock
355	    Uses 8 times oversampling (compared to 16 times for 16650)
356	    Missing break detection (but break generation)
357	    Missing framing error detection
358	    Missing parity bit
359	    Missing receive time-out interrupt
360	    Missing DCD, DSR, DTR and RI signals
361
362	  If unsure, say N.
363
364config SERIAL_8250_FSL
365	bool
366	depends on SERIAL_8250_CONSOLE
367	default PPC || ARM || ARM64
368
369config SERIAL_8250_DW
370	tristate "Support for Synopsys DesignWare 8250 quirks"
371	depends on SERIAL_8250
372	select SERIAL_8250_DWLIB
373	help
374	  Selecting this option will enable handling of the extra features
375	  present in the Synopsys DesignWare APB UART.
376
377config SERIAL_8250_EM
378	tristate "Support for Emma Mobile integrated serial port"
379	depends on SERIAL_8250 && ARM && HAVE_CLK
380	help
381	  Selecting this option will add support for the integrated serial
382	  port hardware found on the Emma Mobile line of processors.
383	  If unsure, say N.
384
385config SERIAL_8250_IOC3
386	tristate "SGI IOC3 8250 UART support"
387	depends on SGI_MFD_IOC3 && SERIAL_8250
388	select SERIAL_8250_EXTENDED
389	select SERIAL_8250_SHARE_IRQ
390	help
391	  Enable this if you have a SGI Origin or Octane machine. This module
392	  provides basic serial support by directly driving the UART chip
393	  behind the IOC3 device on those systems.  Maximum baud speed is
394	  38400bps using this driver.
395
396config SERIAL_8250_RT288X
397	bool "Ralink RT288x/RT305x/RT3662/RT3883 serial port support"
398	depends on SERIAL_8250
399	default y if MIPS_ALCHEMY || SOC_RT288X || SOC_RT305X || SOC_RT3883 || SOC_MT7620
400	help
401	  Selecting this option will add support for the alternate register
402	  layout used by Ralink RT288x/RT305x, Alchemy Au1xxx, and some others.
403	  If unsure, say N.
404
405config SERIAL_8250_OMAP
406	tristate "Support for OMAP internal UART (8250 based driver)"
407	depends on SERIAL_8250 && (ARCH_OMAP2PLUS || ARCH_K3)
408	help
409	  If you have a machine based on an Texas Instruments OMAP CPU you
410	  can enable its onboard serial ports by enabling this option.
411
412	  This driver uses ttyS instead of ttyO.
413
414config SERIAL_8250_OMAP_TTYO_FIXUP
415	bool "Replace ttyO with ttyS"
416	depends on SERIAL_8250_OMAP=y && SERIAL_8250_CONSOLE
417	default y
418	help
419	  This option replaces the "console=ttyO" argument with the matching
420	  ttyS argument if the user did not specified it on the command line.
421	  This ensures that the user can see the kernel output during boot
422	  which he wouldn't see otherwise. The getty has still to be configured
423	  for ttyS instead of ttyO regardless of this option.
424	  This option is intended for people who "automatically" enable this
425	  driver without knowing that this driver requires a different console=
426	  argument. If you read this, please keep this option disabled and
427	  instead update your kernel command line. If you prepare a kernel for a
428	  distribution or other kind of larger user base then you probably want
429	  to keep this option enabled. Otherwise people might complain about a
430	  not booting kernel because the serial console remains silent in case
431	  they forgot to update the command line.
432
433config SERIAL_8250_LPC18XX
434	tristate "NXP LPC18xx/43xx serial port support"
435	depends on SERIAL_8250 && OF && (ARCH_LPC18XX || COMPILE_TEST)
436	default ARCH_LPC18XX
437	help
438	  If you have a LPC18xx/43xx based board and want to use the
439	  serial port, say Y to this option. If unsure, say Y.
440
441config SERIAL_8250_MT6577
442	tristate "Mediatek serial port support"
443	depends on SERIAL_8250 && ARCH_MEDIATEK
444	help
445	  If you have a Mediatek based board and want to use the
446	  serial port, say Y to this option. If unsure, say N.
447
448config SERIAL_8250_UNIPHIER
449	tristate "Support for UniPhier on-chip UART"
450	depends on SERIAL_8250
451	depends on ARCH_UNIPHIER || COMPILE_TEST
452	help
453	  If you have a UniPhier based board and want to use the on-chip
454	  serial ports, say Y to this option. If unsure, say N.
455
456config SERIAL_8250_INGENIC
457	tristate "Support for Ingenic SoC serial ports"
458	depends on SERIAL_8250
459	depends on OF_FLATTREE
460	depends on MIPS || COMPILE_TEST
461	help
462	  If you have a system using an Ingenic SoC and wish to make use of
463	  its UARTs, say Y to this option. If unsure, say N.
464
465config SERIAL_8250_LPSS
466	tristate "Support for serial ports on Intel LPSS platforms"
467	default SERIAL_8250
468	depends on SERIAL_8250 && PCI
469	depends on X86 || COMPILE_TEST
470	select SERIAL_8250_DWLIB
471	select DW_DMAC_CORE if SERIAL_8250_DMA
472	select DW_DMAC_PCI if (SERIAL_8250_DMA && X86_INTEL_LPSS)
473	select RATIONAL
474	help
475	  Selecting this option will enable handling of the extra features
476	  present on the UART found on various Intel platforms such as:
477	    - Intel Baytrail SoC
478	    - Intel Braswell SoC
479	    - Intel Quark X1000 SoC
480
481config SERIAL_8250_MID
482	tristate "Support for serial ports on Intel MID platforms"
483	default SERIAL_8250
484	depends on SERIAL_8250 && PCI
485	depends on X86 || COMPILE_TEST
486	select HSU_DMA if SERIAL_8250_DMA
487	select HSU_DMA_PCI if (HSU_DMA && X86_INTEL_MID)
488	select RATIONAL
489	help
490	  Selecting this option will enable handling of the extra features
491	  present on the UART found on Intel Medfield SOC and various other
492	  Intel platforms.
493
494config SERIAL_8250_PXA
495	tristate "PXA serial port support"
496	depends on SERIAL_8250
497	depends on ARCH_PXA || ARCH_MMP
498	help
499	  If you have a machine based on an Intel XScale PXA2xx CPU you can
500	  enable its onboard serial ports by enabling this option. The option is
501	  applicable to both devicetree and legacy boards, and early console is
502	  part of its support.
503
504config SERIAL_8250_TEGRA
505	tristate "8250 support for Tegra serial ports"
506	default SERIAL_8250
507	depends on SERIAL_8250
508	depends on ARCH_TEGRA || COMPILE_TEST
509	help
510	  Select this option if you have machine with an NVIDIA Tegra SoC and
511	  wish to enable 8250 serial driver for the Tegra serial interfaces.
512
513config SERIAL_OF_PLATFORM
514	tristate "Devicetree based probing for 8250 ports"
515	depends on SERIAL_8250 && OF
516	help
517	  This option is used for all 8250 compatible serial ports that
518	  are probed through devicetree, including Open Firmware based
519	  PowerPC systems and embedded systems on architectures using the
520	  flattened device tree format.
521