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 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