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_GSC 120 tristate 121 depends on SERIAL_8250 && GSC 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 help 258 If you want to use the virtual UART (VUART) device on Aspeed 259 BMC platforms, enable this option. This enables the 16550A- 260 compatible device on the local LPC bus, giving a UART device 261 with no physical RS232 connections. 262 263config SERIAL_8250_BOCA 264 tristate "Support Boca cards" 265 depends on SERIAL_8250 != n && ISA && SERIAL_8250_MANY_PORTS 266 help 267 Say Y here if you have a Boca serial board. Please read the Boca 268 mini-HOWTO, available from <https://www.tldp.org/docs.html#howto> 269 270 To compile this driver as a module, choose M here: the module 271 will be called 8250_boca. 272 273config SERIAL_8250_EXAR_ST16C554 274 tristate "Support Exar ST16C554/554D Quad UART" 275 depends on SERIAL_8250 != n && ISA && SERIAL_8250_MANY_PORTS 276 help 277 The Uplogix Envoy TU301 uses this Exar Quad UART. If you are 278 tinkering with your Envoy TU301, or have a machine with this UART, 279 say Y here. 280 281 To compile this driver as a module, choose M here: the module 282 will be called 8250_exar_st16c554. 283 284config SERIAL_8250_HUB6 285 tristate "Support Hub6 cards" 286 depends on SERIAL_8250 != n && ISA && SERIAL_8250_MANY_PORTS 287 help 288 Say Y here if you have a HUB6 serial board. 289 290 To compile this driver as a module, choose M here: the module 291 will be called 8250_hub6. 292 293# 294# Misc. options/drivers. 295# 296 297config SERIAL_8250_SHARE_IRQ 298 bool "Support for sharing serial interrupts" 299 depends on SERIAL_8250_EXTENDED 300 help 301 Some serial boards have hardware support which allows multiple dumb 302 serial ports on the same board to share a single IRQ. To enable 303 support for this in the serial driver, say Y here. 304 305config SERIAL_8250_DETECT_IRQ 306 bool "Autodetect IRQ on standard ports (unsafe)" 307 depends on SERIAL_8250_EXTENDED 308 help 309 Say Y here if you want the kernel to try to guess which IRQ 310 to use for your serial port. 311 312 This is considered unsafe; it is far better to configure the IRQ in 313 a boot script using the setserial command. 314 315 If unsure, say N. 316 317config SERIAL_8250_RSA 318 bool "Support RSA serial ports" 319 depends on SERIAL_8250_EXTENDED 320 help 321 Say Y here if you have a IODATA RSA-DV II/S ISA card and 322 would like to use its >115kbps speeds. 323 You will need to provide module parameter "probe_rsa", or boot-time 324 parameter 8250.probe_rsa with I/O addresses of this card then. 325 326 If you don't have such card, or if unsure, say N. 327 328config SERIAL_8250_DWLIB 329 bool 330 331config SERIAL_8250_ACORN 332 tristate "Acorn expansion card serial port support" 333 depends on ARCH_ACORN && SERIAL_8250 334 help 335 If you have an Atomwide Serial card or Serial Port card for an Acorn 336 system, say Y to this option. The driver can handle 1, 2, or 3 port 337 cards. If unsure, say N. 338 339config SERIAL_8250_BCM2835AUX 340 tristate "BCM2835 auxiliar mini UART support" 341 depends on ARCH_BCM2835 || COMPILE_TEST 342 depends on SERIAL_8250 && SERIAL_8250_SHARE_IRQ 343 help 344 Support for the BCM2835 auxiliar mini UART. 345 346 Features and limitations of the UART are 347 Registers are similar to 16650 registers, 348 set bits in the control registers that are unsupported 349 are ignored and read back as 0 350 7/8 bit operation with 1 start and 1 stop bit 351 8 symbols deep fifo for rx and tx 352 SW controlled RTS and SW readable CTS 353 Clock rate derived from system clock 354 Uses 8 times oversampling (compared to 16 times for 16650) 355 Missing break detection (but break generation) 356 Missing framing error detection 357 Missing parity bit 358 Missing receive time-out interrupt 359 Missing DCD, DSR, DTR and RI signals 360 361 If unsure, say N. 362 363config SERIAL_8250_FSL 364 bool 365 depends on SERIAL_8250_CONSOLE 366 default PPC || ARM || ARM64 || COMPILE_TEST 367 368config SERIAL_8250_DW 369 tristate "Support for Synopsys DesignWare 8250 quirks" 370 depends on SERIAL_8250 371 select SERIAL_8250_DWLIB 372 help 373 Selecting this option will enable handling of the extra features 374 present in the Synopsys DesignWare APB UART. 375 376config SERIAL_8250_EM 377 tristate "Support for Emma Mobile integrated serial port" 378 depends on SERIAL_8250 && HAVE_CLK 379 depends on (ARM && ARCH_RENESAS) || COMPILE_TEST 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 SERIAL_8250 388 depends on SGI_MFD_IOC3 || COMPILE_TEST 389 select SERIAL_8250_EXTENDED 390 select SERIAL_8250_SHARE_IRQ 391 help 392 Enable this if you have a SGI Origin or Octane machine. This module 393 provides basic serial support by directly driving the UART chip 394 behind the IOC3 device on those systems. Maximum baud speed is 395 38400bps using this driver. 396 397config SERIAL_8250_RT288X 398 bool "Ralink RT288x/RT305x/RT3662/RT3883 serial port support" 399 depends on SERIAL_8250 400 default y if MIPS_ALCHEMY || SOC_RT288X || SOC_RT305X || SOC_RT3883 || SOC_MT7620 401 help 402 Selecting this option will add support for the alternate register 403 layout used by Ralink RT288x/RT305x, Alchemy Au1xxx, and some others. 404 If unsure, say N. 405 406config SERIAL_8250_OMAP 407 tristate "Support for OMAP internal UART (8250 based driver)" 408 depends on SERIAL_8250 409 depends on ARCH_OMAP2PLUS || ARCH_K3 || COMPILE_TEST 410 help 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. 413 414 This driver uses ttyS instead of ttyO. 415 416config SERIAL_8250_OMAP_TTYO_FIXUP 417 bool "Replace ttyO with ttyS" 418 depends on SERIAL_8250_OMAP=y && SERIAL_8250_CONSOLE 419 default y 420 help 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. 434 435config SERIAL_8250_LPC18XX 436 tristate "NXP LPC18xx/43xx serial port support" 437 depends on SERIAL_8250 && OF && (ARCH_LPC18XX || COMPILE_TEST) 438 default ARCH_LPC18XX 439 help 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. 442 443config SERIAL_8250_MT6577 444 tristate "Mediatek serial port support" 445 depends on SERIAL_8250 446 depends on ARCH_MEDIATEK || COMPILE_TEST 447 help 448 If you have a Mediatek based board and want to use the 449 serial port, say Y to this option. If unsure, say N. 450 451config SERIAL_8250_UNIPHIER 452 tristate "Support for UniPhier on-chip UART" 453 depends on SERIAL_8250 454 depends on ARCH_UNIPHIER || COMPILE_TEST 455 help 456 If you have a UniPhier based board and want to use the on-chip 457 serial ports, say Y to this option. If unsure, say N. 458 459config SERIAL_8250_INGENIC 460 tristate "Support for Ingenic SoC serial ports" 461 depends on SERIAL_8250 462 depends on OF_FLATTREE 463 depends on MIPS || COMPILE_TEST 464 help 465 If you have a system using an Ingenic SoC and wish to make use of 466 its UARTs, say Y to this option. If unsure, say N. 467 468config SERIAL_8250_LPSS 469 tristate "Support for serial ports on Intel LPSS platforms" 470 default SERIAL_8250 471 depends on SERIAL_8250 && PCI 472 depends on X86 || COMPILE_TEST 473 select SERIAL_8250_DWLIB 474 select DW_DMAC_CORE if SERIAL_8250_DMA 475 select DW_DMAC_PCI if (SERIAL_8250_DMA && X86_INTEL_LPSS) 476 select RATIONAL 477 help 478 Selecting this option will enable handling of the extra features 479 present on the UART found on various Intel platforms such as: 480 - Intel Baytrail SoC 481 - Intel Braswell SoC 482 - Intel Quark X1000 SoC 483 484config SERIAL_8250_MID 485 tristate "Support for serial ports on Intel MID platforms" 486 default SERIAL_8250 487 depends on SERIAL_8250 && PCI 488 depends on X86 || COMPILE_TEST 489 select HSU_DMA if SERIAL_8250_DMA 490 select HSU_DMA_PCI if (HSU_DMA && X86_INTEL_MID) 491 select RATIONAL 492 help 493 Selecting this option will enable handling of the extra features 494 present on the UART found on Intel Medfield SOC and various other 495 Intel platforms. 496 497config SERIAL_8250_PXA 498 tristate "PXA serial port support" 499 depends on SERIAL_8250 500 depends on ARCH_PXA || ARCH_MMP || COMPILE_TEST 501 help 502 If you have a machine based on an Intel XScale PXA2xx CPU you can 503 enable its onboard serial ports by enabling this option. The option is 504 applicable to both devicetree and legacy boards, and early console is 505 part of its support. 506 507config SERIAL_8250_TEGRA 508 tristate "8250 support for Tegra serial ports" 509 default SERIAL_8250 510 depends on SERIAL_8250 511 depends on ARCH_TEGRA || COMPILE_TEST 512 help 513 Select this option if you have machine with an NVIDIA Tegra SoC and 514 wish to enable 8250 serial driver for the Tegra serial interfaces. 515 516config SERIAL_8250_BCM7271 517 tristate "Broadcom 8250 based serial port" 518 depends on SERIAL_8250 && (ARCH_BRCMSTB || COMPILE_TEST) 519 default ARCH_BRCMSTB 520 help 521 If you have a Broadcom STB based board and want to use the 522 enhanced features of the Broadcom 8250 based serial port, 523 including DMA support and high accuracy BAUD rates, say 524 Y to this option. If unsure, say N. 525 526config SERIAL_OF_PLATFORM 527 tristate "Devicetree based probing for 8250 ports" 528 depends on SERIAL_8250 && OF 529 help 530 This option is used for all 8250 compatible serial ports that 531 are probed through devicetree, including Open Firmware based 532 PowerPC systems and embedded systems on architectures using the 533 flattened device tree format. 534