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