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