1 # SPDX-License-Identifier: GPL-2.0
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.
8 tristate "8250/16550 and compatible serial support"
11 select SERIAL_MCTRL_GPIO if GPIOLIB
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.)
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
28 BTW1: If you have a mouseman serial mouse which is not recognized by
29 the X window system, try running gpm first.
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.
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.
38 config SERIAL_8250_DEPRECATED_OPTIONS
39 bool "Support 8250_core.* kernel options (DEPRECATED)"
40 depends on SERIAL_8250
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
50 If 8250 is built as a module, this adds 8250_core alias instead.
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.
55 config SERIAL_8250_PNP
56 bool "8250/16550 PNP device support" if EXPERT
57 depends on SERIAL_8250 && PNP
60 This builds standard PNP serial support. You may be able to
61 disable this feature if you only need legacy serial support.
63 config SERIAL_8250_16550A_VARIANTS
64 bool "Support for variants of the 16550A serial port"
65 depends on SERIAL_8250
68 The 8250 driver can probe for many variants of the venerable 16550A
69 serial port. Doing so takes additional time at boot.
71 On modern systems, especially those using serial only for a simple
72 console, you can say N here.
74 config SERIAL_8250_FINTEK
75 bool "Support for Fintek F81216A LPC to 4 UART RS485 API"
76 depends on SERIAL_8250
78 Selecting this option will add support for the RS485 capabilities
79 of the Fintek F81216A LPC to 4 UART.
81 If this option is not selected the device will be configured as a
82 standard 16550A serial port.
86 config 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
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
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.)
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
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
114 "earlycon=uart8250,io,0x3f8,9600n8"
115 "earlycon=uart8250,mmio,0xff5e0000,115200n8".
116 it will not only setup early console.
120 config SERIAL_8250_GSC
122 depends on SERIAL_8250 && PARISC
125 config SERIAL_8250_DMA
126 bool "DMA support for 16550 compatible UART controllers" if EXPERT
127 depends on SERIAL_8250 && DMADEVICES=y
130 This builds DMA support that can be used with 8250/16650
131 compatible UART controllers that support DMA signaling.
133 config SERIAL_8250_PCI
134 tristate "8250/16550 PCI device support"
135 depends on SERIAL_8250 && PCI
138 This builds standard PCI serial support. You may be able to
139 disable this feature if you only need legacy serial support.
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.
144 config SERIAL_8250_EXAR
145 tristate "8250/16550 Exar/Commtech PCI/PCIe device support"
146 depends on SERIAL_8250_PCI
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.
153 config SERIAL_8250_HP300
155 depends on SERIAL_8250 && HP300
158 config SERIAL_8250_CS
159 tristate "8250/16550 PCMCIA device support"
160 depends on PCMCIA && SERIAL_8250
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.)
167 To compile this driver as a module, choose M here: the
168 module will be called serial_cs.
172 config SERIAL_8250_MEN_MCB
173 tristate "MEN MCB UART device support"
174 depends on MCB && SERIAL_8250
176 This enables support for FPGA based UARTs found on many MEN
177 boards. This driver enables support for the 16z025, 16z057
180 To compile this driver as a module, chose M here: the
181 module will be called 8250_men_mcb.
184 config SERIAL_8250_NR_UARTS
185 int "Maximum number of 8250/16550 serial ports"
186 depends on SERIAL_8250
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.
194 config 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
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
205 config SERIAL_8250_EXTENDED
206 bool "Extended 8250/16550 serial driver options"
207 depends on SERIAL_8250
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.
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.
218 config SERIAL_8250_MANY_PORTS
219 bool "Support more than 4 legacy serial ports"
220 depends on SERIAL_8250_EXTENDED && !IA64
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.
232 # Multi-port serial cards
235 config SERIAL_8250_FOURPORT
236 tristate "Support Fourport cards"
237 depends on SERIAL_8250 != n && ISA && SERIAL_8250_MANY_PORTS
239 Say Y here if you have an AST FourPort serial board.
241 To compile this driver as a module, choose M here: the module
242 will be called 8250_fourport.
244 config SERIAL_8250_ACCENT
245 tristate "Support Accent cards"
246 depends on SERIAL_8250 != n && ISA && SERIAL_8250_MANY_PORTS
248 Say Y here if you have an Accent Async serial board.
250 To compile this driver as a module, choose M here: the module
251 will be called 8250_accent.
253 config SERIAL_8250_ASPEED_VUART
254 tristate "Aspeed Virtual UART"
255 depends on SERIAL_8250
257 depends on MFD_SYSCON
258 depends on ARCH_ASPEED || COMPILE_TEST
261 If you want to use the virtual UART (VUART) device on Aspeed
262 BMC platforms, enable this option. This enables the 16550A-
263 compatible device on the local LPC bus, giving a UART device
264 with no physical RS232 connections.
266 config SERIAL_8250_BOCA
267 tristate "Support Boca cards"
268 depends on SERIAL_8250 != n && ISA && SERIAL_8250_MANY_PORTS
270 Say Y here if you have a Boca serial board. Please read the Boca
271 mini-HOWTO, available from <https://www.tldp.org/docs.html#howto>
273 To compile this driver as a module, choose M here: the module
274 will be called 8250_boca.
276 config SERIAL_8250_EXAR_ST16C554
277 tristate "Support Exar ST16C554/554D Quad UART"
278 depends on SERIAL_8250 != n && ISA && SERIAL_8250_MANY_PORTS
280 The Uplogix Envoy TU301 uses this Exar Quad UART. If you are
281 tinkering with your Envoy TU301, or have a machine with this UART,
284 To compile this driver as a module, choose M here: the module
285 will be called 8250_exar_st16c554.
287 config SERIAL_8250_HUB6
288 tristate "Support Hub6 cards"
289 depends on SERIAL_8250 != n && ISA && SERIAL_8250_MANY_PORTS
291 Say Y here if you have a HUB6 serial board.
293 To compile this driver as a module, choose M here: the module
294 will be called 8250_hub6.
297 # Misc. options/drivers.
300 config SERIAL_8250_SHARE_IRQ
301 bool "Support for sharing serial interrupts"
302 depends on SERIAL_8250_EXTENDED
304 Some serial boards have hardware support which allows multiple dumb
305 serial ports on the same board to share a single IRQ. To enable
306 support for this in the serial driver, say Y here.
308 config SERIAL_8250_DETECT_IRQ
309 bool "Autodetect IRQ on standard ports (unsafe)"
310 depends on SERIAL_8250_EXTENDED
312 Say Y here if you want the kernel to try to guess which IRQ
313 to use for your serial port.
315 This is considered unsafe; it is far better to configure the IRQ in
316 a boot script using the setserial command.
320 config SERIAL_8250_RSA
321 bool "Support RSA serial ports"
322 depends on SERIAL_8250_EXTENDED
324 Say Y here if you have a IODATA RSA-DV II/S ISA card and
325 would like to use its >115kbps speeds.
326 You will need to provide module parameter "probe_rsa", or boot-time
327 parameter 8250.probe_rsa with I/O addresses of this card then.
329 If you don't have such card, or if unsure, say N.
331 config SERIAL_8250_DWLIB
334 config SERIAL_8250_ACORN
335 tristate "Acorn expansion card serial port support"
336 depends on ARCH_ACORN && SERIAL_8250
338 If you have an Atomwide Serial card or Serial Port card for an Acorn
339 system, say Y to this option. The driver can handle 1, 2, or 3 port
340 cards. If unsure, say N.
342 config SERIAL_8250_BCM2835AUX
343 tristate "BCM2835 auxiliar mini UART support"
344 depends on ARCH_BCM2835 || COMPILE_TEST
345 depends on SERIAL_8250 && SERIAL_8250_SHARE_IRQ
347 Support for the BCM2835 auxiliar mini UART.
349 Features and limitations of the UART are
350 Registers are similar to 16650 registers,
351 set bits in the control registers that are unsupported
352 are ignored and read back as 0
353 7/8 bit operation with 1 start and 1 stop bit
354 8 symbols deep fifo for rx and tx
355 SW controlled RTS and SW readable CTS
356 Clock rate derived from system clock
357 Uses 8 times oversampling (compared to 16 times for 16650)
358 Missing break detection (but break generation)
359 Missing framing error detection
361 Missing receive time-out interrupt
362 Missing DCD, DSR, DTR and RI signals
366 config SERIAL_8250_FSL
368 depends on SERIAL_8250_CONSOLE
369 default PPC || ARM || ARM64
371 config SERIAL_8250_DW
372 tristate "Support for Synopsys DesignWare 8250 quirks"
373 depends on SERIAL_8250
374 select SERIAL_8250_DWLIB
376 Selecting this option will enable handling of the extra features
377 present in the Synopsys DesignWare APB UART.
379 config SERIAL_8250_EM
380 tristate "Support for Emma Mobile integrated serial port"
381 depends on SERIAL_8250 && ARM && HAVE_CLK
383 Selecting this option will add support for the integrated serial
384 port hardware found on the Emma Mobile line of processors.
387 config SERIAL_8250_IOC3
388 tristate "SGI IOC3 8250 UART support"
389 depends on SGI_MFD_IOC3 && SERIAL_8250
390 select SERIAL_8250_EXTENDED
391 select SERIAL_8250_SHARE_IRQ
393 Enable this if you have a SGI Origin or Octane machine. This module
394 provides basic serial support by directly driving the UART chip
395 behind the IOC3 device on those systems. Maximum baud speed is
396 38400bps using this driver.
398 config SERIAL_8250_RT288X
399 bool "Ralink RT288x/RT305x/RT3662/RT3883 serial port support"
400 depends on SERIAL_8250
401 default y if MIPS_ALCHEMY || SOC_RT288X || SOC_RT305X || SOC_RT3883 || SOC_MT7620
403 Selecting this option will add support for the alternate register
404 layout used by Ralink RT288x/RT305x, Alchemy Au1xxx, and some others.
407 config SERIAL_8250_OMAP
408 tristate "Support for OMAP internal UART (8250 based driver)"
409 depends on SERIAL_8250 && (ARCH_OMAP2PLUS || ARCH_K3)
411 If you have a machine based on an Texas Instruments OMAP CPU you
412 can enable its onboard serial ports by enabling this option.
414 This driver uses ttyS instead of ttyO.
416 config SERIAL_8250_OMAP_TTYO_FIXUP
417 bool "Replace ttyO with ttyS"
418 depends on SERIAL_8250_OMAP=y && SERIAL_8250_CONSOLE
421 This option replaces the "console=ttyO" argument with the matching
422 ttyS argument if the user did not specified it on the command line.
423 This ensures that the user can see the kernel output during boot
424 which he wouldn't see otherwise. The getty has still to be configured
425 for ttyS instead of ttyO regardless of this option.
426 This option is intended for people who "automatically" enable this
427 driver without knowing that this driver requires a different console=
428 argument. If you read this, please keep this option disabled and
429 instead update your kernel command line. If you prepare a kernel for a
430 distribution or other kind of larger user base then you probably want
431 to keep this option enabled. Otherwise people might complain about a
432 not booting kernel because the serial console remains silent in case
433 they forgot to update the command line.
435 config SERIAL_8250_LPC18XX
436 tristate "NXP LPC18xx/43xx serial port support"
437 depends on SERIAL_8250 && OF && (ARCH_LPC18XX || COMPILE_TEST)
440 If you have a LPC18xx/43xx based board and want to use the
441 serial port, say Y to this option. If unsure, say Y.
443 config SERIAL_8250_MT6577
444 tristate "Mediatek serial port support"
445 depends on SERIAL_8250 && ARCH_MEDIATEK
447 If you have a Mediatek based board and want to use the
448 serial port, say Y to this option. If unsure, say N.
450 config SERIAL_8250_UNIPHIER
451 tristate "Support for UniPhier on-chip UART"
452 depends on SERIAL_8250
453 depends on ARCH_UNIPHIER || COMPILE_TEST
455 If you have a UniPhier based board and want to use the on-chip
456 serial ports, say Y to this option. If unsure, say N.
458 config SERIAL_8250_INGENIC
459 tristate "Support for Ingenic SoC serial ports"
460 depends on SERIAL_8250
461 depends on OF_FLATTREE
462 depends on MIPS || COMPILE_TEST
464 If you have a system using an Ingenic SoC and wish to make use of
465 its UARTs, say Y to this option. If unsure, say N.
467 config SERIAL_8250_LPSS
468 tristate "Support for serial ports on Intel LPSS platforms"
470 depends on SERIAL_8250 && PCI
471 depends on X86 || COMPILE_TEST
472 select SERIAL_8250_DWLIB
473 select DW_DMAC_CORE if SERIAL_8250_DMA
474 select DW_DMAC_PCI if (SERIAL_8250_DMA && X86_INTEL_LPSS)
477 Selecting this option will enable handling of the extra features
478 present on the UART found on various Intel platforms such as:
481 - Intel Quark X1000 SoC
483 config SERIAL_8250_MID
484 tristate "Support for serial ports on Intel MID platforms"
486 depends on SERIAL_8250 && PCI
487 depends on X86 || COMPILE_TEST
488 select HSU_DMA if SERIAL_8250_DMA
489 select HSU_DMA_PCI if (HSU_DMA && X86_INTEL_MID)
492 Selecting this option will enable handling of the extra features
493 present on the UART found on Intel Medfield SOC and various other
496 config SERIAL_8250_PXA
497 tristate "PXA serial port support"
498 depends on SERIAL_8250
499 depends on ARCH_PXA || ARCH_MMP
501 If you have a machine based on an Intel XScale PXA2xx CPU you can
502 enable its onboard serial ports by enabling this option. The option is
503 applicable to both devicetree and legacy boards, and early console is
506 config SERIAL_8250_TEGRA
507 tristate "8250 support for Tegra serial ports"
509 depends on SERIAL_8250
510 depends on ARCH_TEGRA || COMPILE_TEST
512 Select this option if you have machine with an NVIDIA Tegra SoC and
513 wish to enable 8250 serial driver for the Tegra serial interfaces.
515 config SERIAL_OF_PLATFORM
516 tristate "Devicetree based probing for 8250 ports"
517 depends on SERIAL_8250 && OF
519 This option is used for all 8250 compatible serial ports that
520 are probed through devicetree, including Open Firmware based
521 PowerPC systems and embedded systems on architectures using the
522 flattened device tree format.