xref: /openbmc/linux/drivers/tty/serial/8250/Kconfig (revision 35e6bcd1)
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.
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_16550A_VARIANTS
63	bool "Support for variants of the 16550A serial port"
64	depends on SERIAL_8250
65	default !X86
66	help
67	  The 8250 driver can probe for many variants of the venerable 16550A
68	  serial port. Doing so takes additional time at boot.
69
70	  On modern systems, especially those using serial only for a simple
71	  console, you can say N here.
72
73config SERIAL_8250_FINTEK
74	bool "Support for Fintek F81216A LPC to 4 UART RS485 API"
75	depends on SERIAL_8250
76	help
77	  Selecting this option will add support for the RS485 capabilities
78	  of the Fintek F81216A LPC to 4 UART.
79
80	  If this option is not selected the device will be configured as a
81	  standard 16550A serial port.
82
83	  If unsure, say N.
84
85config SERIAL_8250_CONSOLE
86	bool "Console on 8250/16550 and compatible serial port"
87	depends on SERIAL_8250=y
88	select SERIAL_CORE_CONSOLE
89	select SERIAL_EARLYCON
90	help
91	  If you say Y here, it will be possible to use a serial port as the
92	  system console (the system console is the device which receives all
93	  kernel messages and warnings and which allows logins in single user
94	  mode). This could be useful if some terminal or printer is connected
95	  to that serial port.
96
97	  Even if you say Y here, the currently visible virtual console
98	  (/dev/tty0) will still be used as the system console by default, but
99	  you can alter that using a kernel command line option such as
100	  "console=ttyS1". (Try "man bootparam" or see the documentation of
101	  your boot loader (grub or lilo or loadlin) about how to pass options
102	  to the kernel at boot time.)
103
104	  If you don't have a VGA card installed and you say Y here, the
105	  kernel will automatically use the first serial line, /dev/ttyS0, as
106	  system console.
107
108	  You can set that using a kernel command line option such as
109	  "console=uart8250,io,0x3f8,9600n8"
110	  "console=uart8250,mmio,0xff5e0000,115200n8".
111	  and it will switch to normal serial console when the corresponding
112	  port is ready.
113	  "earlycon=uart8250,io,0x3f8,9600n8"
114	  "earlycon=uart8250,mmio,0xff5e0000,115200n8".
115	  it will not only setup early console.
116
117	  If unsure, say N.
118
119config SERIAL_8250_PARISC
120	tristate
121	depends on SERIAL_8250 && PARISC
122	default SERIAL_8250
123
124config SERIAL_8250_DMA
125	bool "DMA support for 16550 compatible UART controllers" if EXPERT
126	depends on SERIAL_8250 && DMADEVICES=y
127	default SERIAL_8250
128	help
129	  This builds DMA support that can be used with 8250/16650
130	  compatible UART controllers that support DMA signaling.
131
132config SERIAL_8250_PCILIB
133	bool
134
135config SERIAL_8250_PCI
136	tristate "8250/16550 PCI device support"
137	depends on SERIAL_8250 && PCI
138	select SERIAL_8250_PCILIB
139	default SERIAL_8250
140	help
141	  This builds standard PCI serial support. You may be able to
142	  disable this feature if you only need legacy serial support.
143	  Saves about 9K.
144	  Note that serial ports on NetMos 9835 Multi-I/O cards are handled
145	  by the parport_serial driver, enabled with CONFIG_PARPORT_SERIAL.
146
147config SERIAL_8250_EXAR
148	tristate "8250/16550 Exar/Commtech PCI/PCIe device support"
149	depends on SERIAL_8250_PCI
150	default SERIAL_8250
151	help
152	  This builds support for XR17C1xx, XR17V3xx and some Commtech
153	  422x PCIe serial cards that are not covered by the more generic
154	  SERIAL_8250_PCI option.
155
156config SERIAL_8250_HP300
157	tristate
158	depends on SERIAL_8250 && HP300
159	default SERIAL_8250
160
161config SERIAL_8250_CS
162	tristate "8250/16550 PCMCIA device support"
163	depends on PCMCIA && SERIAL_8250
164	help
165	  Say Y here to enable support for 16-bit PCMCIA serial devices,
166	  including serial port cards, modems, and the modem functions of
167	  multi-function Ethernet/modem cards. (PCMCIA- or PC-cards are
168	  credit-card size devices often used with laptops.)
169
170	  To compile this driver as a module, choose M here: the
171	  module will be called serial_cs.
172
173	  If unsure, say N.
174
175config SERIAL_8250_MEN_MCB
176	tristate "MEN MCB UART device support"
177	depends on MCB && SERIAL_8250
178	help
179	  This enables support for FPGA based UARTs found on many MEN
180	  boards. This driver enables support for the 16z025, 16z057
181	  and 16z125 UARTs.
182
183	  To compile this driver as a module, chose M here: the
184	  module will be called 8250_men_mcb.
185
186
187config SERIAL_8250_NR_UARTS
188	int "Maximum number of 8250/16550 serial ports"
189	depends on SERIAL_8250
190	default "4"
191	help
192	  Set this to the number of serial ports you want the driver
193	  to support.  This includes any ports discovered via ACPI or
194	  PCI enumeration and any ports that may be added at run-time
195	  via hot-plug, or any ISA multi-port serial cards.
196
197config SERIAL_8250_RUNTIME_UARTS
198	int "Number of 8250/16550 serial ports to register at runtime"
199	depends on SERIAL_8250
200	range 0 SERIAL_8250_NR_UARTS
201	default "4"
202	help
203	  Set this to the maximum number of serial ports you want
204	  the kernel to register at boot time.  This can be overridden
205	  with the module parameter "nr_uarts", or boot-time parameter
206	  8250.nr_uarts
207
208config SERIAL_8250_EXTENDED
209	bool "Extended 8250/16550 serial driver options"
210	depends on SERIAL_8250
211	help
212	  If you wish to use any non-standard features of the standard "dumb"
213	  driver, say Y here. This includes HUB6 support, shared serial
214	  interrupts, special multiport support, support for more than the
215	  four COM 1/2/3/4 boards, etc.
216
217	  Note that the answer to this question won't directly affect the
218	  kernel: saying N will just cause the configurator to skip all
219	  the questions about serial driver options. If unsure, say N.
220
221config SERIAL_8250_MANY_PORTS
222	bool "Support more than 4 legacy serial ports"
223	depends on SERIAL_8250_EXTENDED && !IA64
224	help
225	  Say Y here if you have dumb serial boards other than the four
226	  standard COM 1/2/3/4 ports. This may happen if you have an AST
227	  FourPort, Accent Async, Boca (read the Boca mini-HOWTO, available
228	  from <https://www.tldp.org/docs.html#howto>), or other custom
229	  serial port hardware which acts similar to standard serial port
230	  hardware. If you only use the standard COM 1/2/3/4 ports, you can
231	  say N here to save some memory. You can also say Y if you have an
232	  "intelligent" multiport card such as Digiboards, etc.
233
234#
235# Multi-port serial cards
236#
237
238config SERIAL_8250_FOURPORT
239	tristate "Support Fourport cards"
240	depends on SERIAL_8250 != n && ISA && SERIAL_8250_MANY_PORTS
241	help
242	  Say Y here if you have an AST FourPort serial board.
243
244	  To compile this driver as a module, choose M here: the module
245	  will be called 8250_fourport.
246
247config SERIAL_8250_ACCENT
248	tristate "Support Accent cards"
249	depends on SERIAL_8250 != n && ISA && SERIAL_8250_MANY_PORTS
250	help
251	  Say Y here if you have an Accent Async serial board.
252
253	  To compile this driver as a module, choose M here: the module
254	  will be called 8250_accent.
255
256config SERIAL_8250_ASPEED_VUART
257	tristate "Aspeed Virtual UART"
258	depends on SERIAL_8250
259	depends on OF
260	depends on MFD_SYSCON
261	depends on ARCH_ASPEED || COMPILE_TEST
262	select REGMAP
263	help
264	  If you want to use the virtual UART (VUART) device on Aspeed
265	  BMC platforms, enable this option. This enables the 16550A-
266	  compatible device on the local LPC bus, giving a UART device
267	  with no physical RS232 connections.
268
269config SERIAL_8250_BOCA
270	tristate "Support Boca cards"
271	depends on SERIAL_8250 != n && ISA && SERIAL_8250_MANY_PORTS
272	help
273	  Say Y here if you have a Boca serial board.  Please read the Boca
274	  mini-HOWTO, available from <https://www.tldp.org/docs.html#howto>
275
276	  To compile this driver as a module, choose M here: the module
277	  will be called 8250_boca.
278
279config SERIAL_8250_EXAR_ST16C554
280	tristate "Support Exar ST16C554/554D Quad UART"
281	depends on SERIAL_8250 != n && ISA && SERIAL_8250_MANY_PORTS
282	help
283	  The Uplogix Envoy TU301 uses this Exar Quad UART.  If you are
284	  tinkering with your Envoy TU301, or have a machine with this UART,
285	  say Y here.
286
287	  To compile this driver as a module, choose M here: the module
288	  will be called 8250_exar_st16c554.
289
290config SERIAL_8250_HUB6
291	tristate "Support Hub6 cards"
292	depends on SERIAL_8250 != n && ISA && SERIAL_8250_MANY_PORTS
293	help
294	  Say Y here if you have a HUB6 serial board.
295
296	  To compile this driver as a module, choose M here: the module
297	  will be called 8250_hub6.
298
299config SERIAL_8250_PCI1XXXX
300	tristate "Microchip 8250 based serial port"
301	depends on SERIAL_8250 && PCI
302	select SERIAL_8250_PCILIB
303	help
304	 Select this option if you have a setup with Microchip PCIe
305	 Switch with serial port enabled and wish to enable 8250
306	 serial driver for the serial interface. This driver support
307	 will ensure to support baud rates upto 1.5Mpbs.
308
309#
310# Misc. options/drivers.
311#
312
313config SERIAL_8250_SHARE_IRQ
314	bool "Support for sharing serial interrupts"
315	depends on SERIAL_8250_EXTENDED
316	help
317	  Some serial boards have hardware support which allows multiple dumb
318	  serial ports on the same board to share a single IRQ. To enable
319	  support for this in the serial driver, say Y here.
320
321config SERIAL_8250_DETECT_IRQ
322	bool "Autodetect IRQ on standard ports (unsafe)"
323	depends on SERIAL_8250_EXTENDED
324	help
325	  Say Y here if you want the kernel to try to guess which IRQ
326	  to use for your serial port.
327
328	  This is considered unsafe; it is far better to configure the IRQ in
329	  a boot script using the setserial command.
330
331	  If unsure, say N.
332
333config SERIAL_8250_RSA
334	bool "Support RSA serial ports"
335	depends on SERIAL_8250_EXTENDED
336	help
337	  Say Y here if you have a IODATA RSA-DV II/S ISA card and
338	  would like to use its >115kbps speeds.
339	  You will need to provide module parameter "probe_rsa", or boot-time
340	  parameter 8250.probe_rsa with I/O addresses of this card then.
341
342	  If you don't have such card, or if unsure, say N.
343
344config SERIAL_8250_DWLIB
345	bool
346
347config SERIAL_8250_ACORN
348	tristate "Acorn expansion card serial port support"
349	depends on ARCH_ACORN && SERIAL_8250
350	help
351	  If you have an Atomwide Serial card or Serial Port card for an Acorn
352	  system, say Y to this option.  The driver can handle 1, 2, or 3 port
353	  cards.  If unsure, say N.
354
355config SERIAL_8250_BCM2835AUX
356	tristate "BCM2835 auxiliar mini UART support"
357	depends on ARCH_BCM2835 || COMPILE_TEST
358	depends on SERIAL_8250 && SERIAL_8250_SHARE_IRQ
359	help
360	  Support for the BCM2835 auxiliar mini UART.
361
362	  Features and limitations of the UART are
363	    Registers are similar to 16650 registers,
364	      set bits in the control registers that are unsupported
365	      are ignored and read back as 0
366	    7/8 bit operation with 1 start and 1 stop bit
367	    8 symbols deep fifo for rx and tx
368	    SW controlled RTS and SW readable CTS
369	    Clock rate derived from system clock
370	    Uses 8 times oversampling (compared to 16 times for 16650)
371	    Missing break detection (but break generation)
372	    Missing framing error detection
373	    Missing parity bit
374	    Missing receive time-out interrupt
375	    Missing DCD, DSR, DTR and RI signals
376
377	  If unsure, say N.
378
379config SERIAL_8250_FSL
380	bool "Freescale 16550 UART support" if COMPILE_TEST && !(PPC || ARM || ARM64)
381	depends on SERIAL_8250_CONSOLE
382	default PPC || ARM || ARM64
383	help
384	  Selecting this option enables a workaround for a break-detection
385	  erratum for Freescale 16550 UARTs in the 8250 driver. It also
386	  enables support for ACPI enumeration.
387
388config SERIAL_8250_DFL
389	tristate "DFL bus driver for Altera 16550 UART"
390	depends on SERIAL_8250 && FPGA_DFL
391	help
392	  This option enables support for a Device Feature List (DFL) bus
393	  driver for the Altera 16550 UART. One or more Altera 16550 UARTs
394	  can be instantiated in a FPGA and then be discovered during
395	  enumeration of the DFL bus.
396
397	  To compile this driver as a module, chose M here: the
398	  module will be called 8250_dfl.
399
400config SERIAL_8250_DW
401	tristate "Support for Synopsys DesignWare 8250 quirks"
402	depends on SERIAL_8250
403	select SERIAL_8250_DWLIB
404	help
405	  Selecting this option will enable handling of the extra features
406	  present in the Synopsys DesignWare APB UART.
407
408config SERIAL_8250_EM
409	tristate "Support for Emma Mobile integrated serial port"
410	depends on SERIAL_8250 && HAVE_CLK
411	depends on ARCH_RENESAS || COMPILE_TEST
412	help
413	  Selecting this option will add support for the integrated serial
414	  port hardware found on the Emma Mobile line of processors.
415	  If unsure, say N.
416
417config SERIAL_8250_IOC3
418	tristate "SGI IOC3 8250 UART support"
419	depends on SERIAL_8250
420	depends on SGI_MFD_IOC3 || COMPILE_TEST
421	select SERIAL_8250_EXTENDED
422	select SERIAL_8250_SHARE_IRQ
423	help
424	  Enable this if you have a SGI Origin or Octane machine. This module
425	  provides basic serial support by directly driving the UART chip
426	  behind the IOC3 device on those systems.  Maximum baud speed is
427	  38400bps using this driver.
428
429config SERIAL_8250_RT288X
430	bool "Ralink RT288x/RT305x/RT3662/RT3883 serial port support"
431	depends on SERIAL_8250
432	default y if MIPS_ALCHEMY || SOC_RT288X || SOC_RT305X || SOC_RT3883 || SOC_MT7620
433	help
434	  Selecting this option will add support for the alternate register
435	  layout used by Ralink RT288x/RT305x, Alchemy Au1xxx, and some others.
436	  If unsure, say N.
437
438config SERIAL_8250_OMAP
439	tristate "Support for OMAP internal UART (8250 based driver)"
440	depends on SERIAL_8250
441	depends on ARCH_OMAP2PLUS || ARCH_K3 || COMPILE_TEST
442	help
443	  If you have a machine based on an Texas Instruments OMAP CPU you
444	  can enable its onboard serial ports by enabling this option.
445
446	  This driver uses ttyS instead of ttyO.
447
448config SERIAL_8250_OMAP_TTYO_FIXUP
449	bool "Replace ttyO with ttyS"
450	depends on SERIAL_8250_OMAP=y && SERIAL_8250_CONSOLE
451	default y
452	help
453	  This option replaces the "console=ttyO" argument with the matching
454	  ttyS argument if the user did not specified it on the command line.
455	  This ensures that the user can see the kernel output during boot
456	  which he wouldn't see otherwise. The getty has still to be configured
457	  for ttyS instead of ttyO regardless of this option.
458	  This option is intended for people who "automatically" enable this
459	  driver without knowing that this driver requires a different console=
460	  argument. If you read this, please keep this option disabled and
461	  instead update your kernel command line. If you prepare a kernel for a
462	  distribution or other kind of larger user base then you probably want
463	  to keep this option enabled. Otherwise people might complain about a
464	  not booting kernel because the serial console remains silent in case
465	  they forgot to update the command line.
466
467config SERIAL_8250_LPC18XX
468	tristate "NXP LPC18xx/43xx serial port support"
469	depends on SERIAL_8250 && OF && (ARCH_LPC18XX || COMPILE_TEST)
470	default ARCH_LPC18XX
471	help
472	  If you have a LPC18xx/43xx based board and want to use the
473	  serial port, say Y to this option. If unsure, say Y.
474
475config SERIAL_8250_MT6577
476	tristate "Mediatek serial port support"
477	depends on SERIAL_8250
478	depends on ARCH_MEDIATEK || COMPILE_TEST
479	help
480	  If you have a Mediatek based board and want to use the
481	  serial port, say Y to this option. If unsure, say N.
482
483config SERIAL_8250_UNIPHIER
484	tristate "Support for UniPhier on-chip UART"
485	depends on SERIAL_8250
486	depends on ARCH_UNIPHIER || COMPILE_TEST
487	help
488	  If you have a UniPhier based board and want to use the on-chip
489	  serial ports, say Y to this option. If unsure, say N.
490
491config SERIAL_8250_INGENIC
492	tristate "Support for Ingenic SoC serial ports"
493	depends on SERIAL_8250
494	depends on OF_FLATTREE
495	depends on MIPS || COMPILE_TEST
496	help
497	  If you have a system using an Ingenic SoC and wish to make use of
498	  its UARTs, say Y to this option. If unsure, say N.
499
500config SERIAL_8250_LPSS
501	tristate "Support for serial ports on Intel LPSS platforms"
502	default SERIAL_8250
503	depends on SERIAL_8250 && PCI
504	depends on X86 || COMPILE_TEST
505	select SERIAL_8250_DWLIB
506	select DW_DMAC_CORE if SERIAL_8250_DMA
507	select DW_DMAC_PCI if (SERIAL_8250_DMA && X86_INTEL_LPSS)
508	select RATIONAL
509	help
510	  Selecting this option will enable handling of the UART found on
511	  various Intel platforms such as:
512	    - Intel Baytrail SoC
513	    - Intel Braswell SoC
514	    - Intel Quark X1000 SoC
515	  that are not covered by the more generic SERIAL_8250_PCI option.
516
517config SERIAL_8250_MID
518	tristate "Support for serial ports on Intel MID platforms"
519	default SERIAL_8250
520	depends on SERIAL_8250 && PCI
521	depends on X86 || COMPILE_TEST
522	select HSU_DMA if SERIAL_8250_DMA
523	select HSU_DMA_PCI if (HSU_DMA && X86_INTEL_MID)
524	select RATIONAL
525	help
526	  Selecting this option will enable handling of the UART found on
527	  Intel Medfield SOC and various other Intel platforms that is not
528	  covered by the more generic SERIAL_8250_PCI option.
529
530config SERIAL_8250_PERICOM
531	tristate "Support for Pericom and Acces I/O serial ports"
532	default SERIAL_8250
533	depends on SERIAL_8250 && PCI
534	help
535	  Selecting this option will enable handling of the Pericom and Acces
536	  I/O UARTs that are not covered by the more generic SERIAL_8250_PCI
537	  option.
538
539config SERIAL_8250_PXA
540	tristate "PXA serial port support"
541	depends on SERIAL_8250
542	depends on ARCH_PXA || ARCH_MMP || COMPILE_TEST
543	help
544	  If you have a machine based on an Intel XScale PXA2xx CPU you can
545	  enable its onboard serial ports by enabling this option. The option is
546	  applicable to both devicetree and legacy boards, and early console is
547	  part of its support.
548
549config SERIAL_8250_TEGRA
550	tristate "8250 support for Tegra serial ports"
551	default SERIAL_8250
552	depends on SERIAL_8250
553	depends on ARCH_TEGRA || COMPILE_TEST
554	help
555	  Select this option if you have machine with an NVIDIA Tegra SoC and
556	  wish to enable 8250 serial driver for the Tegra serial interfaces.
557
558config SERIAL_8250_BCM7271
559	tristate "Broadcom 8250 based serial port"
560	depends on SERIAL_8250 && (ARCH_BRCMSTB || COMPILE_TEST)
561	default ARCH_BRCMSTB
562	help
563	  If you have a Broadcom STB based board and want to use the
564	  enhanced features of the Broadcom 8250 based serial port,
565	  including DMA support and high accuracy BAUD rates, say
566	  Y to this option. If unsure, say N.
567
568config SERIAL_OF_PLATFORM
569	tristate "Devicetree based probing for 8250 ports"
570	depends on SERIAL_8250 && OF
571	help
572	  This option is used for all 8250 compatible serial ports that
573	  are probed through devicetree, including Open Firmware based
574	  PowerPC systems and embedded systems on architectures using the
575	  flattened device tree format.
576