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_PCI
133	tristate "8250/16550 PCI device support"
134	depends on SERIAL_8250 && PCI
135	default SERIAL_8250
136	help
137	  This builds standard PCI serial support. You may be able to
138	  disable this feature if you only need legacy serial support.
139	  Saves about 9K.
140	  Note that serial ports on NetMos 9835 Multi-I/O cards are handled
141	  by the parport_serial driver, enabled with CONFIG_PARPORT_SERIAL.
142
143config SERIAL_8250_EXAR
144	tristate "8250/16550 Exar/Commtech PCI/PCIe device support"
145	depends on SERIAL_8250_PCI
146	default SERIAL_8250
147	help
148	  This builds support for XR17C1xx, XR17V3xx and some Commtech
149	  422x PCIe serial cards that are not covered by the more generic
150	  SERIAL_8250_PCI option.
151
152config SERIAL_8250_HP300
153	tristate
154	depends on SERIAL_8250 && HP300
155	default SERIAL_8250
156
157config SERIAL_8250_CS
158	tristate "8250/16550 PCMCIA device support"
159	depends on PCMCIA && SERIAL_8250
160	help
161	  Say Y here to enable support for 16-bit PCMCIA serial devices,
162	  including serial port cards, modems, and the modem functions of
163	  multi-function Ethernet/modem cards. (PCMCIA- or PC-cards are
164	  credit-card size devices often used with laptops.)
165
166	  To compile this driver as a module, choose M here: the
167	  module will be called serial_cs.
168
169	  If unsure, say N.
170
171config SERIAL_8250_MEN_MCB
172	tristate "MEN MCB UART device support"
173	depends on MCB && SERIAL_8250
174	help
175	  This enables support for FPGA based UARTs found on many MEN
176	  boards. This driver enables support for the 16z025, 16z057
177	  and 16z125 UARTs.
178
179	  To compile this driver as a module, chose M here: the
180	  module will be called 8250_men_mcb.
181
182
183config SERIAL_8250_NR_UARTS
184	int "Maximum number of 8250/16550 serial ports"
185	depends on SERIAL_8250
186	default "4"
187	help
188	  Set this to the number of serial ports you want the driver
189	  to support.  This includes any ports discovered via ACPI or
190	  PCI enumeration and any ports that may be added at run-time
191	  via hot-plug, or any ISA multi-port serial cards.
192
193config SERIAL_8250_RUNTIME_UARTS
194	int "Number of 8250/16550 serial ports to register at runtime"
195	depends on SERIAL_8250
196	range 0 SERIAL_8250_NR_UARTS
197	default "4"
198	help
199	  Set this to the maximum number of serial ports you want
200	  the kernel to register at boot time.  This can be overridden
201	  with the module parameter "nr_uarts", or boot-time parameter
202	  8250.nr_uarts
203
204config SERIAL_8250_EXTENDED
205	bool "Extended 8250/16550 serial driver options"
206	depends on SERIAL_8250
207	help
208	  If you wish to use any non-standard features of the standard "dumb"
209	  driver, say Y here. This includes HUB6 support, shared serial
210	  interrupts, special multiport support, support for more than the
211	  four COM 1/2/3/4 boards, etc.
212
213	  Note that the answer to this question won't directly affect the
214	  kernel: saying N will just cause the configurator to skip all
215	  the questions about serial driver options. If unsure, say N.
216
217config SERIAL_8250_MANY_PORTS
218	bool "Support more than 4 legacy serial ports"
219	depends on SERIAL_8250_EXTENDED && !IA64
220	help
221	  Say Y here if you have dumb serial boards other than the four
222	  standard COM 1/2/3/4 ports. This may happen if you have an AST
223	  FourPort, Accent Async, Boca (read the Boca mini-HOWTO, available
224	  from <https://www.tldp.org/docs.html#howto>), or other custom
225	  serial port hardware which acts similar to standard serial port
226	  hardware. If you only use the standard COM 1/2/3/4 ports, you can
227	  say N here to save some memory. You can also say Y if you have an
228	  "intelligent" multiport card such as Digiboards, etc.
229
230#
231# Multi-port serial cards
232#
233
234config SERIAL_8250_FOURPORT
235	tristate "Support Fourport cards"
236	depends on SERIAL_8250 != n && ISA && SERIAL_8250_MANY_PORTS
237	help
238	  Say Y here if you have an AST FourPort serial board.
239
240	  To compile this driver as a module, choose M here: the module
241	  will be called 8250_fourport.
242
243config SERIAL_8250_ACCENT
244	tristate "Support Accent cards"
245	depends on SERIAL_8250 != n && ISA && SERIAL_8250_MANY_PORTS
246	help
247	  Say Y here if you have an Accent Async serial board.
248
249	  To compile this driver as a module, choose M here: the module
250	  will be called 8250_accent.
251
252config SERIAL_8250_ASPEED_VUART
253	tristate "Aspeed Virtual UART"
254	depends on SERIAL_8250
255	depends on OF
256	depends on REGMAP && MFD_SYSCON
257	depends on ARCH_ASPEED || COMPILE_TEST
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 "Freescale 16550 UART support" if COMPILE_TEST && !(PPC || ARM || ARM64)
366	depends on SERIAL_8250_CONSOLE
367	default PPC || ARM || ARM64
368	help
369	  Selecting this option enables a workaround for a break-detection
370	  erratum for Freescale 16550 UARTs in the 8250 driver. It also
371	  enables support for ACPI enumeration.
372
373config SERIAL_8250_DW
374	tristate "Support for Synopsys DesignWare 8250 quirks"
375	depends on SERIAL_8250
376	select SERIAL_8250_DWLIB
377	help
378	  Selecting this option will enable handling of the extra features
379	  present in the Synopsys DesignWare APB UART.
380
381config SERIAL_8250_EM
382	tristate "Support for Emma Mobile integrated serial port"
383	depends on SERIAL_8250 && HAVE_CLK
384	depends on ARCH_RENESAS || COMPILE_TEST
385	help
386	  Selecting this option will add support for the integrated serial
387	  port hardware found on the Emma Mobile line of processors.
388	  If unsure, say N.
389
390config SERIAL_8250_IOC3
391	tristate "SGI IOC3 8250 UART support"
392	depends on SERIAL_8250
393	depends on SGI_MFD_IOC3 || COMPILE_TEST
394	select SERIAL_8250_EXTENDED
395	select SERIAL_8250_SHARE_IRQ
396	help
397	  Enable this if you have a SGI Origin or Octane machine. This module
398	  provides basic serial support by directly driving the UART chip
399	  behind the IOC3 device on those systems.  Maximum baud speed is
400	  38400bps using this driver.
401
402config SERIAL_8250_RT288X
403	bool "Ralink RT288x/RT305x/RT3662/RT3883 serial port support"
404	depends on SERIAL_8250
405	default y if MIPS_ALCHEMY || SOC_RT288X || SOC_RT305X || SOC_RT3883 || SOC_MT7620
406	help
407	  Selecting this option will add support for the alternate register
408	  layout used by Ralink RT288x/RT305x, Alchemy Au1xxx, and some others.
409	  If unsure, say N.
410
411config SERIAL_8250_OMAP
412	tristate "Support for OMAP internal UART (8250 based driver)"
413	depends on SERIAL_8250
414	depends on ARCH_OMAP2PLUS || ARCH_K3 || COMPILE_TEST
415	help
416	  If you have a machine based on an Texas Instruments OMAP CPU you
417	  can enable its onboard serial ports by enabling this option.
418
419	  This driver uses ttyS instead of ttyO.
420
421config SERIAL_8250_OMAP_TTYO_FIXUP
422	bool "Replace ttyO with ttyS"
423	depends on SERIAL_8250_OMAP=y && SERIAL_8250_CONSOLE
424	default y
425	help
426	  This option replaces the "console=ttyO" argument with the matching
427	  ttyS argument if the user did not specified it on the command line.
428	  This ensures that the user can see the kernel output during boot
429	  which he wouldn't see otherwise. The getty has still to be configured
430	  for ttyS instead of ttyO regardless of this option.
431	  This option is intended for people who "automatically" enable this
432	  driver without knowing that this driver requires a different console=
433	  argument. If you read this, please keep this option disabled and
434	  instead update your kernel command line. If you prepare a kernel for a
435	  distribution or other kind of larger user base then you probably want
436	  to keep this option enabled. Otherwise people might complain about a
437	  not booting kernel because the serial console remains silent in case
438	  they forgot to update the command line.
439
440config SERIAL_8250_LPC18XX
441	tristate "NXP LPC18xx/43xx serial port support"
442	depends on SERIAL_8250 && OF && (ARCH_LPC18XX || COMPILE_TEST)
443	default ARCH_LPC18XX
444	help
445	  If you have a LPC18xx/43xx based board and want to use the
446	  serial port, say Y to this option. If unsure, say Y.
447
448config SERIAL_8250_MT6577
449	tristate "Mediatek serial port support"
450	depends on SERIAL_8250
451	depends on ARCH_MEDIATEK || COMPILE_TEST
452	help
453	  If you have a Mediatek based board and want to use the
454	  serial port, say Y to this option. If unsure, say N.
455
456config SERIAL_8250_UNIPHIER
457	tristate "Support for UniPhier on-chip UART"
458	depends on SERIAL_8250
459	depends on ARCH_UNIPHIER || COMPILE_TEST
460	help
461	  If you have a UniPhier based board and want to use the on-chip
462	  serial ports, say Y to this option. If unsure, say N.
463
464config SERIAL_8250_INGENIC
465	tristate "Support for Ingenic SoC serial ports"
466	depends on SERIAL_8250
467	depends on OF_FLATTREE
468	depends on MIPS || COMPILE_TEST
469	help
470	  If you have a system using an Ingenic SoC and wish to make use of
471	  its UARTs, say Y to this option. If unsure, say N.
472
473config SERIAL_8250_LPSS
474	tristate "Support for serial ports on Intel LPSS platforms"
475	default SERIAL_8250
476	depends on SERIAL_8250 && PCI
477	depends on X86 || COMPILE_TEST
478	select SERIAL_8250_DWLIB
479	select DW_DMAC_CORE if SERIAL_8250_DMA
480	select DW_DMAC_PCI if (SERIAL_8250_DMA && X86_INTEL_LPSS)
481	select RATIONAL
482	help
483	  Selecting this option will enable handling of the UART found on
484	  various Intel platforms such as:
485	    - Intel Baytrail SoC
486	    - Intel Braswell SoC
487	    - Intel Quark X1000 SoC
488	  that are not covered by the more generic SERIAL_8250_PCI option.
489
490config SERIAL_8250_MID
491	tristate "Support for serial ports on Intel MID platforms"
492	default SERIAL_8250
493	depends on SERIAL_8250 && PCI
494	depends on X86 || COMPILE_TEST
495	select HSU_DMA if SERIAL_8250_DMA
496	select HSU_DMA_PCI if (HSU_DMA && X86_INTEL_MID)
497	select RATIONAL
498	help
499	  Selecting this option will enable handling of the UART found on
500	  Intel Medfield SOC and various other Intel platforms that is not
501	  covered by the more generic SERIAL_8250_PCI option.
502
503config SERIAL_8250_PERICOM
504	tristate "Support for Pericom and Acces I/O serial ports"
505	default SERIAL_8250
506	depends on SERIAL_8250 && PCI
507	help
508	  Selecting this option will enable handling of the Pericom and Acces
509	  I/O UARTs that are not covered by the more generic SERIAL_8250_PCI
510	  option.
511
512config SERIAL_8250_PXA
513	tristate "PXA serial port support"
514	depends on SERIAL_8250
515	depends on ARCH_PXA || ARCH_MMP || COMPILE_TEST
516	help
517	  If you have a machine based on an Intel XScale PXA2xx CPU you can
518	  enable its onboard serial ports by enabling this option. The option is
519	  applicable to both devicetree and legacy boards, and early console is
520	  part of its support.
521
522config SERIAL_8250_TEGRA
523	tristate "8250 support for Tegra serial ports"
524	default SERIAL_8250
525	depends on SERIAL_8250
526	depends on ARCH_TEGRA || COMPILE_TEST
527	help
528	  Select this option if you have machine with an NVIDIA Tegra SoC and
529	  wish to enable 8250 serial driver for the Tegra serial interfaces.
530
531config SERIAL_8250_BCM7271
532	tristate "Broadcom 8250 based serial port"
533	depends on SERIAL_8250 && (ARCH_BRCMSTB || COMPILE_TEST)
534	default ARCH_BRCMSTB
535	help
536	  If you have a Broadcom STB based board and want to use the
537	  enhanced features of the Broadcom 8250 based serial port,
538	  including DMA support and high accuracy BAUD rates, say
539	  Y to this option. If unsure, say N.
540
541config SERIAL_OF_PLATFORM
542	tristate "Devicetree based probing for 8250 ports"
543	depends on SERIAL_8250 && OF
544	help
545	  This option is used for all 8250 compatible serial ports that
546	  are probed through devicetree, including Open Firmware based
547	  PowerPC systems and embedded systems on architectures using the
548	  flattened device tree format.
549