1 /* SPDX-License-Identifier: GPL-2.0-or-later */ 2 /* 3 * linux/drivers/char/serial_core.h 4 * 5 * Copyright (C) 2000 Deep Blue Solutions Ltd. 6 */ 7 #ifndef LINUX_SERIAL_CORE_H 8 #define LINUX_SERIAL_CORE_H 9 10 #include <linux/bitops.h> 11 #include <linux/compiler.h> 12 #include <linux/console.h> 13 #include <linux/interrupt.h> 14 #include <linux/lockdep.h> 15 #include <linux/printk.h> 16 #include <linux/spinlock.h> 17 #include <linux/sched.h> 18 #include <linux/tty.h> 19 #include <linux/mutex.h> 20 #include <linux/sysrq.h> 21 #include <uapi/linux/serial_core.h> 22 23 #ifdef CONFIG_SERIAL_CORE_CONSOLE 24 #define uart_console(port) \ 25 ((port)->cons && (port)->cons->index == (port)->line) 26 #else 27 #define uart_console(port) ({ (void)port; 0; }) 28 #endif 29 30 struct uart_port; 31 struct serial_struct; 32 struct serial_port_device; 33 struct device; 34 struct gpio_desc; 35 36 /** 37 * struct uart_ops -- interface between serial_core and the driver 38 * 39 * This structure describes all the operations that can be done on the 40 * physical hardware. 41 * 42 * @tx_empty: ``unsigned int ()(struct uart_port *port)`` 43 * 44 * This function tests whether the transmitter fifo and shifter for the 45 * @port is empty. If it is empty, this function should return 46 * %TIOCSER_TEMT, otherwise return 0. If the port does not support this 47 * operation, then it should return %TIOCSER_TEMT. 48 * 49 * Locking: none. 50 * Interrupts: caller dependent. 51 * This call must not sleep 52 * 53 * @set_mctrl: ``void ()(struct uart_port *port, unsigned int mctrl)`` 54 * 55 * This function sets the modem control lines for @port to the state 56 * described by @mctrl. The relevant bits of @mctrl are: 57 * 58 * - %TIOCM_RTS RTS signal. 59 * - %TIOCM_DTR DTR signal. 60 * - %TIOCM_OUT1 OUT1 signal. 61 * - %TIOCM_OUT2 OUT2 signal. 62 * - %TIOCM_LOOP Set the port into loopback mode. 63 * 64 * If the appropriate bit is set, the signal should be driven 65 * active. If the bit is clear, the signal should be driven 66 * inactive. 67 * 68 * Locking: @port->lock taken. 69 * Interrupts: locally disabled. 70 * This call must not sleep 71 * 72 * @get_mctrl: ``unsigned int ()(struct uart_port *port)`` 73 * 74 * Returns the current state of modem control inputs of @port. The state 75 * of the outputs should not be returned, since the core keeps track of 76 * their state. The state information should include: 77 * 78 * - %TIOCM_CAR state of DCD signal 79 * - %TIOCM_CTS state of CTS signal 80 * - %TIOCM_DSR state of DSR signal 81 * - %TIOCM_RI state of RI signal 82 * 83 * The bit is set if the signal is currently driven active. If 84 * the port does not support CTS, DCD or DSR, the driver should 85 * indicate that the signal is permanently active. If RI is 86 * not available, the signal should not be indicated as active. 87 * 88 * Locking: @port->lock taken. 89 * Interrupts: locally disabled. 90 * This call must not sleep 91 * 92 * @stop_tx: ``void ()(struct uart_port *port)`` 93 * 94 * Stop transmitting characters. This might be due to the CTS line 95 * becoming inactive or the tty layer indicating we want to stop 96 * transmission due to an %XOFF character. 97 * 98 * The driver should stop transmitting characters as soon as possible. 99 * 100 * Locking: @port->lock taken. 101 * Interrupts: locally disabled. 102 * This call must not sleep 103 * 104 * @start_tx: ``void ()(struct uart_port *port)`` 105 * 106 * Start transmitting characters. 107 * 108 * Locking: @port->lock taken. 109 * Interrupts: locally disabled. 110 * This call must not sleep 111 * 112 * @throttle: ``void ()(struct uart_port *port)`` 113 * 114 * Notify the serial driver that input buffers for the line discipline are 115 * close to full, and it should somehow signal that no more characters 116 * should be sent to the serial port. 117 * This will be called only if hardware assisted flow control is enabled. 118 * 119 * Locking: serialized with @unthrottle() and termios modification by the 120 * tty layer. 121 * 122 * @unthrottle: ``void ()(struct uart_port *port)`` 123 * 124 * Notify the serial driver that characters can now be sent to the serial 125 * port without fear of overrunning the input buffers of the line 126 * disciplines. 127 * 128 * This will be called only if hardware assisted flow control is enabled. 129 * 130 * Locking: serialized with @throttle() and termios modification by the 131 * tty layer. 132 * 133 * @send_xchar: ``void ()(struct uart_port *port, char ch)`` 134 * 135 * Transmit a high priority character, even if the port is stopped. This 136 * is used to implement XON/XOFF flow control and tcflow(). If the serial 137 * driver does not implement this function, the tty core will append the 138 * character to the circular buffer and then call start_tx() / stop_tx() 139 * to flush the data out. 140 * 141 * Do not transmit if @ch == '\0' (%__DISABLED_CHAR). 142 * 143 * Locking: none. 144 * Interrupts: caller dependent. 145 * 146 * @start_rx: ``void ()(struct uart_port *port)`` 147 * 148 * Start receiving characters. 149 * 150 * Locking: @port->lock taken. 151 * Interrupts: locally disabled. 152 * This call must not sleep 153 * 154 * @stop_rx: ``void ()(struct uart_port *port)`` 155 * 156 * Stop receiving characters; the @port is in the process of being closed. 157 * 158 * Locking: @port->lock taken. 159 * Interrupts: locally disabled. 160 * This call must not sleep 161 * 162 * @enable_ms: ``void ()(struct uart_port *port)`` 163 * 164 * Enable the modem status interrupts. 165 * 166 * This method may be called multiple times. Modem status interrupts 167 * should be disabled when the @shutdown() method is called. 168 * 169 * Locking: @port->lock taken. 170 * Interrupts: locally disabled. 171 * This call must not sleep 172 * 173 * @break_ctl: ``void ()(struct uart_port *port, int ctl)`` 174 * 175 * Control the transmission of a break signal. If @ctl is nonzero, the 176 * break signal should be transmitted. The signal should be terminated 177 * when another call is made with a zero @ctl. 178 * 179 * Locking: caller holds tty_port->mutex 180 * 181 * @startup: ``int ()(struct uart_port *port)`` 182 * 183 * Grab any interrupt resources and initialise any low level driver state. 184 * Enable the port for reception. It should not activate RTS nor DTR; 185 * this will be done via a separate call to @set_mctrl(). 186 * 187 * This method will only be called when the port is initially opened. 188 * 189 * Locking: port_sem taken. 190 * Interrupts: globally disabled. 191 * 192 * @shutdown: ``void ()(struct uart_port *port)`` 193 * 194 * Disable the @port, disable any break condition that may be in effect, 195 * and free any interrupt resources. It should not disable RTS nor DTR; 196 * this will have already been done via a separate call to @set_mctrl(). 197 * 198 * Drivers must not access @port->state once this call has completed. 199 * 200 * This method will only be called when there are no more users of this 201 * @port. 202 * 203 * Locking: port_sem taken. 204 * Interrupts: caller dependent. 205 * 206 * @flush_buffer: ``void ()(struct uart_port *port)`` 207 * 208 * Flush any write buffers, reset any DMA state and stop any ongoing DMA 209 * transfers. 210 * 211 * This will be called whenever the @port->state->xmit circular buffer is 212 * cleared. 213 * 214 * Locking: @port->lock taken. 215 * Interrupts: locally disabled. 216 * This call must not sleep 217 * 218 * @set_termios: ``void ()(struct uart_port *port, struct ktermios *new, 219 * struct ktermios *old)`` 220 * 221 * Change the @port parameters, including word length, parity, stop bits. 222 * Update @port->read_status_mask and @port->ignore_status_mask to 223 * indicate the types of events we are interested in receiving. Relevant 224 * ktermios::c_cflag bits are: 225 * 226 * - %CSIZE - word size 227 * - %CSTOPB - 2 stop bits 228 * - %PARENB - parity enable 229 * - %PARODD - odd parity (when %PARENB is in force) 230 * - %ADDRB - address bit (changed through uart_port::rs485_config()). 231 * - %CREAD - enable reception of characters (if not set, still receive 232 * characters from the port, but throw them away). 233 * - %CRTSCTS - if set, enable CTS status change reporting. 234 * - %CLOCAL - if not set, enable modem status change reporting. 235 * 236 * Relevant ktermios::c_iflag bits are: 237 * 238 * - %INPCK - enable frame and parity error events to be passed to the TTY 239 * layer. 240 * - %BRKINT / %PARMRK - both of these enable break events to be passed to 241 * the TTY layer. 242 * - %IGNPAR - ignore parity and framing errors. 243 * - %IGNBRK - ignore break errors. If %IGNPAR is also set, ignore overrun 244 * errors as well. 245 * 246 * The interaction of the ktermios::c_iflag bits is as follows (parity 247 * error given as an example): 248 * 249 * ============ ======= ======= ========================================= 250 * Parity error INPCK IGNPAR 251 * ============ ======= ======= ========================================= 252 * n/a 0 n/a character received, marked as %TTY_NORMAL 253 * None 1 n/a character received, marked as %TTY_NORMAL 254 * Yes 1 0 character received, marked as %TTY_PARITY 255 * Yes 1 1 character discarded 256 * ============ ======= ======= ========================================= 257 * 258 * Other flags may be used (eg, xon/xoff characters) if your hardware 259 * supports hardware "soft" flow control. 260 * 261 * Locking: caller holds tty_port->mutex 262 * Interrupts: caller dependent. 263 * This call must not sleep 264 * 265 * @set_ldisc: ``void ()(struct uart_port *port, struct ktermios *termios)`` 266 * 267 * Notifier for discipline change. See 268 * Documentation/driver-api/tty/tty_ldisc.rst. 269 * 270 * Locking: caller holds tty_port->mutex 271 * 272 * @pm: ``void ()(struct uart_port *port, unsigned int state, 273 * unsigned int oldstate)`` 274 * 275 * Perform any power management related activities on the specified @port. 276 * @state indicates the new state (defined by enum uart_pm_state), 277 * @oldstate indicates the previous state. 278 * 279 * This function should not be used to grab any resources. 280 * 281 * This will be called when the @port is initially opened and finally 282 * closed, except when the @port is also the system console. This will 283 * occur even if %CONFIG_PM is not set. 284 * 285 * Locking: none. 286 * Interrupts: caller dependent. 287 * 288 * @type: ``const char *()(struct uart_port *port)`` 289 * 290 * Return a pointer to a string constant describing the specified @port, 291 * or return %NULL, in which case the string 'unknown' is substituted. 292 * 293 * Locking: none. 294 * Interrupts: caller dependent. 295 * 296 * @release_port: ``void ()(struct uart_port *port)`` 297 * 298 * Release any memory and IO region resources currently in use by the 299 * @port. 300 * 301 * Locking: none. 302 * Interrupts: caller dependent. 303 * 304 * @request_port: ``int ()(struct uart_port *port)`` 305 * 306 * Request any memory and IO region resources required by the port. If any 307 * fail, no resources should be registered when this function returns, and 308 * it should return -%EBUSY on failure. 309 * 310 * Locking: none. 311 * Interrupts: caller dependent. 312 * 313 * @config_port: ``void ()(struct uart_port *port, int type)`` 314 * 315 * Perform any autoconfiguration steps required for the @port. @type 316 * contains a bit mask of the required configuration. %UART_CONFIG_TYPE 317 * indicates that the port requires detection and identification. 318 * @port->type should be set to the type found, or %PORT_UNKNOWN if no 319 * port was detected. 320 * 321 * %UART_CONFIG_IRQ indicates autoconfiguration of the interrupt signal, 322 * which should be probed using standard kernel autoprobing techniques. 323 * This is not necessary on platforms where ports have interrupts 324 * internally hard wired (eg, system on a chip implementations). 325 * 326 * Locking: none. 327 * Interrupts: caller dependent. 328 * 329 * @verify_port: ``int ()(struct uart_port *port, 330 * struct serial_struct *serinfo)`` 331 * 332 * Verify the new serial port information contained within @serinfo is 333 * suitable for this port type. 334 * 335 * Locking: none. 336 * Interrupts: caller dependent. 337 * 338 * @ioctl: ``int ()(struct uart_port *port, unsigned int cmd, 339 * unsigned long arg)`` 340 * 341 * Perform any port specific IOCTLs. IOCTL commands must be defined using 342 * the standard numbering system found in <asm/ioctl.h>. 343 * 344 * Locking: none. 345 * Interrupts: caller dependent. 346 * 347 * @poll_init: ``int ()(struct uart_port *port)`` 348 * 349 * Called by kgdb to perform the minimal hardware initialization needed to 350 * support @poll_put_char() and @poll_get_char(). Unlike @startup(), this 351 * should not request interrupts. 352 * 353 * Locking: %tty_mutex and tty_port->mutex taken. 354 * Interrupts: n/a. 355 * 356 * @poll_put_char: ``void ()(struct uart_port *port, unsigned char ch)`` 357 * 358 * Called by kgdb to write a single character @ch directly to the serial 359 * @port. It can and should block until there is space in the TX FIFO. 360 * 361 * Locking: none. 362 * Interrupts: caller dependent. 363 * This call must not sleep 364 * 365 * @poll_get_char: ``int ()(struct uart_port *port)`` 366 * 367 * Called by kgdb to read a single character directly from the serial 368 * port. If data is available, it should be returned; otherwise the 369 * function should return %NO_POLL_CHAR immediately. 370 * 371 * Locking: none. 372 * Interrupts: caller dependent. 373 * This call must not sleep 374 */ 375 struct uart_ops { 376 unsigned int (*tx_empty)(struct uart_port *); 377 void (*set_mctrl)(struct uart_port *, unsigned int mctrl); 378 unsigned int (*get_mctrl)(struct uart_port *); 379 void (*stop_tx)(struct uart_port *); 380 void (*start_tx)(struct uart_port *); 381 void (*throttle)(struct uart_port *); 382 void (*unthrottle)(struct uart_port *); 383 void (*send_xchar)(struct uart_port *, char ch); 384 void (*stop_rx)(struct uart_port *); 385 void (*start_rx)(struct uart_port *); 386 void (*enable_ms)(struct uart_port *); 387 void (*break_ctl)(struct uart_port *, int ctl); 388 int (*startup)(struct uart_port *); 389 void (*shutdown)(struct uart_port *); 390 void (*flush_buffer)(struct uart_port *); 391 void (*set_termios)(struct uart_port *, struct ktermios *new, 392 const struct ktermios *old); 393 void (*set_ldisc)(struct uart_port *, struct ktermios *); 394 void (*pm)(struct uart_port *, unsigned int state, 395 unsigned int oldstate); 396 const char *(*type)(struct uart_port *); 397 void (*release_port)(struct uart_port *); 398 int (*request_port)(struct uart_port *); 399 void (*config_port)(struct uart_port *, int); 400 int (*verify_port)(struct uart_port *, struct serial_struct *); 401 int (*ioctl)(struct uart_port *, unsigned int, unsigned long); 402 #ifdef CONFIG_CONSOLE_POLL 403 int (*poll_init)(struct uart_port *); 404 void (*poll_put_char)(struct uart_port *, unsigned char); 405 int (*poll_get_char)(struct uart_port *); 406 #endif 407 }; 408 409 #define NO_POLL_CHAR 0x00ff0000 410 #define UART_CONFIG_TYPE (1 << 0) 411 #define UART_CONFIG_IRQ (1 << 1) 412 413 struct uart_icount { 414 __u32 cts; 415 __u32 dsr; 416 __u32 rng; 417 __u32 dcd; 418 __u32 rx; 419 __u32 tx; 420 __u32 frame; 421 __u32 overrun; 422 __u32 parity; 423 __u32 brk; 424 __u32 buf_overrun; 425 }; 426 427 typedef u64 __bitwise upf_t; 428 typedef unsigned int __bitwise upstat_t; 429 430 enum uart_iotype { 431 UPIO_UNKNOWN = -1, 432 UPIO_PORT = SERIAL_IO_PORT, /* 8b I/O port access */ 433 UPIO_HUB6 = SERIAL_IO_HUB6, /* Hub6 ISA card */ 434 UPIO_MEM = SERIAL_IO_MEM, /* driver-specific */ 435 UPIO_MEM32 = SERIAL_IO_MEM32, /* 32b little endian */ 436 UPIO_AU = SERIAL_IO_AU, /* Au1x00 and RT288x type IO */ 437 UPIO_TSI = SERIAL_IO_TSI, /* Tsi108/109 type IO */ 438 UPIO_MEM32BE = SERIAL_IO_MEM32BE, /* 32b big endian */ 439 UPIO_MEM16 = SERIAL_IO_MEM16, /* 16b little endian */ 440 }; 441 442 struct uart_port { 443 spinlock_t lock; /* port lock */ 444 unsigned long iobase; /* in/out[bwl] */ 445 unsigned char __iomem *membase; /* read/write[bwl] */ 446 u32 (*serial_in)(struct uart_port *, unsigned int offset); 447 void (*serial_out)(struct uart_port *, unsigned int offset, u32 val); 448 void (*set_termios)(struct uart_port *, 449 struct ktermios *new, 450 const struct ktermios *old); 451 void (*set_ldisc)(struct uart_port *, 452 struct ktermios *); 453 unsigned int (*get_mctrl)(struct uart_port *); 454 void (*set_mctrl)(struct uart_port *, unsigned int); 455 unsigned int (*get_divisor)(struct uart_port *, 456 unsigned int baud, 457 unsigned int *frac); 458 void (*set_divisor)(struct uart_port *, 459 unsigned int baud, 460 unsigned int quot, 461 unsigned int quot_frac); 462 int (*startup)(struct uart_port *port); 463 void (*shutdown)(struct uart_port *port); 464 void (*throttle)(struct uart_port *port); 465 void (*unthrottle)(struct uart_port *port); 466 int (*handle_irq)(struct uart_port *); 467 void (*pm)(struct uart_port *, unsigned int state, 468 unsigned int old); 469 void (*handle_break)(struct uart_port *); 470 int (*rs485_config)(struct uart_port *, 471 struct ktermios *termios, 472 struct serial_rs485 *rs485); 473 int (*iso7816_config)(struct uart_port *, 474 struct serial_iso7816 *iso7816); 475 unsigned int ctrl_id; /* optional serial core controller id */ 476 unsigned int port_id; /* optional serial core port id */ 477 unsigned int irq; /* irq number */ 478 unsigned long irqflags; /* irq flags */ 479 unsigned int uartclk; /* base uart clock */ 480 unsigned int fifosize; /* tx fifo size */ 481 unsigned char x_char; /* xon/xoff char */ 482 unsigned char regshift; /* reg offset shift */ 483 484 unsigned char quirks; /* internal quirks */ 485 486 /* internal quirks must be updated while holding port mutex */ 487 #define UPQ_NO_TXEN_TEST BIT(0) 488 489 enum uart_iotype iotype; /* io access style */ 490 491 unsigned int read_status_mask; /* driver specific */ 492 unsigned int ignore_status_mask; /* driver specific */ 493 struct uart_state *state; /* pointer to parent state */ 494 struct uart_icount icount; /* statistics */ 495 496 struct console *cons; /* struct console, if any */ 497 /* flags must be updated while holding port mutex */ 498 upf_t flags; 499 500 /* 501 * These flags must be equivalent to the flags defined in 502 * include/uapi/linux/tty_flags.h which are the userspace definitions 503 * assigned from the serial_struct flags in uart_set_info() 504 * [for bit definitions in the UPF_CHANGE_MASK] 505 * 506 * Bits [0..ASYNCB_LAST_USER] are userspace defined/visible/changeable 507 * The remaining bits are serial-core specific and not modifiable by 508 * userspace. 509 */ 510 #ifdef CONFIG_HAS_IOPORT 511 #define UPF_FOURPORT ((__force upf_t) ASYNC_FOURPORT /* 1 */ ) 512 #else 513 #define UPF_FOURPORT 0 514 #endif 515 #define UPF_SAK ((__force upf_t) ASYNC_SAK /* 2 */ ) 516 #define UPF_SPD_HI ((__force upf_t) ASYNC_SPD_HI /* 4 */ ) 517 #define UPF_SPD_VHI ((__force upf_t) ASYNC_SPD_VHI /* 5 */ ) 518 #define UPF_SPD_CUST ((__force upf_t) ASYNC_SPD_CUST /* 0x0030 */ ) 519 #define UPF_SPD_WARP ((__force upf_t) ASYNC_SPD_WARP /* 0x1010 */ ) 520 #define UPF_SPD_MASK ((__force upf_t) ASYNC_SPD_MASK /* 0x1030 */ ) 521 #define UPF_SKIP_TEST ((__force upf_t) ASYNC_SKIP_TEST /* 6 */ ) 522 #define UPF_AUTO_IRQ ((__force upf_t) ASYNC_AUTO_IRQ /* 7 */ ) 523 #define UPF_HARDPPS_CD ((__force upf_t) ASYNC_HARDPPS_CD /* 11 */ ) 524 #define UPF_SPD_SHI ((__force upf_t) ASYNC_SPD_SHI /* 12 */ ) 525 #define UPF_LOW_LATENCY ((__force upf_t) ASYNC_LOW_LATENCY /* 13 */ ) 526 #define UPF_BUGGY_UART ((__force upf_t) ASYNC_BUGGY_UART /* 14 */ ) 527 #define UPF_MAGIC_MULTIPLIER ((__force upf_t) ASYNC_MAGIC_MULTIPLIER /* 16 */ ) 528 529 #define UPF_NO_THRE_TEST ((__force upf_t) BIT_ULL(19)) 530 /* Port has hardware-assisted h/w flow control */ 531 #define UPF_AUTO_CTS ((__force upf_t) BIT_ULL(20)) 532 #define UPF_AUTO_RTS ((__force upf_t) BIT_ULL(21)) 533 #define UPF_HARD_FLOW ((__force upf_t) (UPF_AUTO_CTS | UPF_AUTO_RTS)) 534 /* Port has hardware-assisted s/w flow control */ 535 #define UPF_SOFT_FLOW ((__force upf_t) BIT_ULL(22)) 536 #define UPF_CONS_FLOW ((__force upf_t) BIT_ULL(23)) 537 #define UPF_SHARE_IRQ ((__force upf_t) BIT_ULL(24)) 538 #define UPF_EXAR_EFR ((__force upf_t) BIT_ULL(25)) 539 #define UPF_BUG_THRE ((__force upf_t) BIT_ULL(26)) 540 /* The exact UART type is known and should not be probed. */ 541 #define UPF_FIXED_TYPE ((__force upf_t) BIT_ULL(27)) 542 #define UPF_BOOT_AUTOCONF ((__force upf_t) BIT_ULL(28)) 543 #define UPF_FIXED_PORT ((__force upf_t) BIT_ULL(29)) 544 #define UPF_DEAD ((__force upf_t) BIT_ULL(30)) 545 #define UPF_IOREMAP ((__force upf_t) BIT_ULL(31)) 546 #define UPF_FULL_PROBE ((__force upf_t) BIT_ULL(32)) 547 548 #define __UPF_CHANGE_MASK 0x17fff 549 #define UPF_CHANGE_MASK ((__force upf_t) __UPF_CHANGE_MASK) 550 #define UPF_USR_MASK ((__force upf_t) (UPF_SPD_MASK|UPF_LOW_LATENCY)) 551 552 #if __UPF_CHANGE_MASK > ASYNC_FLAGS 553 #error Change mask not equivalent to userspace-visible bit defines 554 #endif 555 556 /* 557 * Must hold termios_rwsem, port mutex and port lock to change; 558 * can hold any one lock to read. 559 */ 560 upstat_t status; 561 562 #define UPSTAT_CTS_ENABLE ((__force upstat_t) (1 << 0)) 563 #define UPSTAT_DCD_ENABLE ((__force upstat_t) (1 << 1)) 564 #define UPSTAT_AUTORTS ((__force upstat_t) (1 << 2)) 565 #define UPSTAT_AUTOCTS ((__force upstat_t) (1 << 3)) 566 #define UPSTAT_AUTOXOFF ((__force upstat_t) (1 << 4)) 567 #define UPSTAT_SYNC_FIFO ((__force upstat_t) (1 << 5)) 568 569 bool hw_stopped; /* sw-assisted CTS flow state */ 570 unsigned int mctrl; /* current modem ctrl settings */ 571 unsigned int frame_time; /* frame timing in ns */ 572 unsigned int type; /* port type */ 573 const struct uart_ops *ops; 574 unsigned int custom_divisor; 575 unsigned int line; /* port index */ 576 unsigned int minor; 577 resource_size_t mapbase; /* for ioremap */ 578 resource_size_t mapsize; 579 struct device *dev; /* serial port physical parent device */ 580 struct serial_port_device *port_dev; /* serial core port device */ 581 582 unsigned long sysrq; /* sysrq timeout */ 583 u8 sysrq_ch; /* char for sysrq */ 584 unsigned char has_sysrq; 585 unsigned char sysrq_seq; /* index in sysrq_toggle_seq */ 586 587 unsigned char hub6; /* this should be in the 8250 driver */ 588 unsigned char suspended; 589 unsigned char console_reinit; 590 const char *name; /* port name */ 591 struct attribute_group *attr_group; /* port specific attributes */ 592 const struct attribute_group **tty_groups; /* all attributes (serial core use only) */ 593 struct serial_rs485 rs485; 594 struct serial_rs485 rs485_supported; /* Supported mask for serial_rs485 */ 595 struct gpio_desc *rs485_term_gpio; /* enable RS485 bus termination */ 596 struct gpio_desc *rs485_rx_during_tx_gpio; /* Output GPIO that sets the state of RS485 RX during TX */ 597 struct serial_iso7816 iso7816; 598 void *private_data; /* generic platform data pointer */ 599 }; 600 601 /* 602 * Only for console->device_lock()/_unlock() callbacks and internal 603 * port lock wrapper synchronization. 604 */ 605 static inline void __uart_port_lock_irqsave(struct uart_port *up, unsigned long *flags) 606 { 607 spin_lock_irqsave(&up->lock, *flags); 608 } 609 610 /* 611 * Only for console->device_lock()/_unlock() callbacks and internal 612 * port lock wrapper synchronization. 613 */ 614 static inline void __uart_port_unlock_irqrestore(struct uart_port *up, unsigned long flags) 615 { 616 spin_unlock_irqrestore(&up->lock, flags); 617 } 618 619 /** 620 * uart_port_set_cons - Safely set the @cons field for a uart 621 * @up: The uart port to set 622 * @con: The new console to set to 623 * 624 * This function must be used to set @up->cons. It uses the port lock to 625 * synchronize with the port lock wrappers in order to ensure that the console 626 * cannot change or disappear while another context is holding the port lock. 627 */ 628 static inline void uart_port_set_cons(struct uart_port *up, struct console *con) 629 { 630 unsigned long flags; 631 632 __uart_port_lock_irqsave(up, &flags); 633 up->cons = con; 634 __uart_port_unlock_irqrestore(up, flags); 635 } 636 637 /* Only for internal port lock wrapper usage. */ 638 static inline bool __uart_port_using_nbcon(struct uart_port *up) 639 { 640 lockdep_assert_held_once(&up->lock); 641 642 if (likely(!uart_console(up))) 643 return false; 644 645 /* 646 * @up->cons is only modified under the port lock. Therefore it is 647 * certain that it cannot disappear here. 648 * 649 * @up->cons->node is added/removed from the console list under the 650 * port lock. Therefore it is certain that the registration status 651 * cannot change here, thus @up->cons->flags can be read directly. 652 */ 653 if (hlist_unhashed_lockless(&up->cons->node) || 654 !(up->cons->flags & CON_NBCON) || 655 !up->cons->write_atomic) { 656 return false; 657 } 658 659 return true; 660 } 661 662 /* Only for internal port lock wrapper usage. */ 663 static inline bool __uart_port_nbcon_try_acquire(struct uart_port *up) 664 { 665 if (!__uart_port_using_nbcon(up)) 666 return true; 667 668 return nbcon_device_try_acquire(up->cons); 669 } 670 671 /* Only for internal port lock wrapper usage. */ 672 static inline void __uart_port_nbcon_acquire(struct uart_port *up) 673 { 674 if (!__uart_port_using_nbcon(up)) 675 return; 676 677 while (!nbcon_device_try_acquire(up->cons)) 678 cpu_relax(); 679 } 680 681 /* Only for internal port lock wrapper usage. */ 682 static inline void __uart_port_nbcon_release(struct uart_port *up) 683 { 684 if (!__uart_port_using_nbcon(up)) 685 return; 686 687 nbcon_device_release(up->cons); 688 } 689 690 /** 691 * uart_port_lock - Lock the UART port 692 * @up: Pointer to UART port structure 693 */ 694 static inline void uart_port_lock(struct uart_port *up) 695 { 696 spin_lock(&up->lock); 697 __uart_port_nbcon_acquire(up); 698 } 699 700 /** 701 * uart_port_lock_irq - Lock the UART port and disable interrupts 702 * @up: Pointer to UART port structure 703 */ 704 static inline void uart_port_lock_irq(struct uart_port *up) 705 { 706 spin_lock_irq(&up->lock); 707 __uart_port_nbcon_acquire(up); 708 } 709 710 /** 711 * uart_port_lock_irqsave - Lock the UART port, save and disable interrupts 712 * @up: Pointer to UART port structure 713 * @flags: Pointer to interrupt flags storage 714 */ 715 static inline void uart_port_lock_irqsave(struct uart_port *up, unsigned long *flags) 716 { 717 spin_lock_irqsave(&up->lock, *flags); 718 __uart_port_nbcon_acquire(up); 719 } 720 721 /** 722 * uart_port_trylock - Try to lock the UART port 723 * @up: Pointer to UART port structure 724 * 725 * Returns: True if lock was acquired, false otherwise 726 */ 727 static inline bool uart_port_trylock(struct uart_port *up) 728 { 729 if (!spin_trylock(&up->lock)) 730 return false; 731 732 if (!__uart_port_nbcon_try_acquire(up)) { 733 spin_unlock(&up->lock); 734 return false; 735 } 736 737 return true; 738 } 739 740 /** 741 * uart_port_trylock_irqsave - Try to lock the UART port, save and disable interrupts 742 * @up: Pointer to UART port structure 743 * @flags: Pointer to interrupt flags storage 744 * 745 * Returns: True if lock was acquired, false otherwise 746 */ 747 static inline bool uart_port_trylock_irqsave(struct uart_port *up, unsigned long *flags) 748 { 749 if (!spin_trylock_irqsave(&up->lock, *flags)) 750 return false; 751 752 if (!__uart_port_nbcon_try_acquire(up)) { 753 spin_unlock_irqrestore(&up->lock, *flags); 754 return false; 755 } 756 757 return true; 758 } 759 760 /** 761 * uart_port_unlock - Unlock the UART port 762 * @up: Pointer to UART port structure 763 */ 764 static inline void uart_port_unlock(struct uart_port *up) 765 { 766 __uart_port_nbcon_release(up); 767 spin_unlock(&up->lock); 768 } 769 770 /** 771 * uart_port_unlock_irq - Unlock the UART port and re-enable interrupts 772 * @up: Pointer to UART port structure 773 */ 774 static inline void uart_port_unlock_irq(struct uart_port *up) 775 { 776 __uart_port_nbcon_release(up); 777 spin_unlock_irq(&up->lock); 778 } 779 780 /** 781 * uart_port_unlock_irqrestore - Unlock the UART port, restore interrupts 782 * @up: Pointer to UART port structure 783 * @flags: The saved interrupt flags for restore 784 */ 785 static inline void uart_port_unlock_irqrestore(struct uart_port *up, unsigned long flags) 786 { 787 __uart_port_nbcon_release(up); 788 spin_unlock_irqrestore(&up->lock, flags); 789 } 790 791 static inline int serial_port_in(struct uart_port *up, int offset) 792 { 793 return up->serial_in(up, offset); 794 } 795 796 static inline void serial_port_out(struct uart_port *up, int offset, int value) 797 { 798 up->serial_out(up, offset, value); 799 } 800 801 /** 802 * enum uart_pm_state - power states for UARTs 803 * @UART_PM_STATE_ON: UART is powered, up and operational 804 * @UART_PM_STATE_OFF: UART is powered off 805 * @UART_PM_STATE_UNDEFINED: sentinel 806 */ 807 enum uart_pm_state { 808 UART_PM_STATE_ON = 0, 809 UART_PM_STATE_OFF = 3, /* number taken from ACPI */ 810 UART_PM_STATE_UNDEFINED, 811 }; 812 813 /* 814 * This is the state information which is persistent across opens. 815 */ 816 struct uart_state { 817 struct tty_port port; 818 819 enum uart_pm_state pm_state; 820 821 atomic_t refcount; 822 wait_queue_head_t remove_wait; 823 struct uart_port *uart_port; 824 }; 825 826 #define UART_XMIT_SIZE PAGE_SIZE 827 828 829 /* number of characters left in xmit buffer before we ask for more */ 830 #define WAKEUP_CHARS 256 831 832 /** 833 * uart_xmit_advance - Advance xmit buffer and account Tx'ed chars 834 * @up: uart_port structure describing the port 835 * @chars: number of characters sent 836 * 837 * This function advances the tail of circular xmit buffer by the number of 838 * @chars transmitted and handles accounting of transmitted bytes (into 839 * @up's icount.tx). 840 */ 841 static inline void uart_xmit_advance(struct uart_port *up, unsigned int chars) 842 { 843 struct tty_port *tport = &up->state->port; 844 845 kfifo_skip_count(&tport->xmit_fifo, chars); 846 up->icount.tx += chars; 847 } 848 849 static inline unsigned int uart_fifo_out(struct uart_port *up, 850 unsigned char *buf, unsigned int chars) 851 { 852 struct tty_port *tport = &up->state->port; 853 854 chars = kfifo_out(&tport->xmit_fifo, buf, chars); 855 up->icount.tx += chars; 856 857 return chars; 858 } 859 860 static inline unsigned int uart_fifo_get(struct uart_port *up, 861 unsigned char *ch) 862 { 863 struct tty_port *tport = &up->state->port; 864 unsigned int chars; 865 866 chars = kfifo_get(&tport->xmit_fifo, ch); 867 up->icount.tx += chars; 868 869 return chars; 870 } 871 872 struct module; 873 struct tty_driver; 874 875 struct uart_driver { 876 struct module *owner; 877 const char *driver_name; 878 const char *dev_name; 879 int major; 880 int minor; 881 int nr; 882 struct console *cons; 883 884 /* 885 * these are private; the low level driver should not 886 * touch these; they should be initialised to NULL 887 */ 888 struct uart_state *state; 889 struct tty_driver *tty_driver; 890 }; 891 892 void uart_write_wakeup(struct uart_port *port); 893 894 /** 895 * enum UART_TX_FLAGS -- flags for uart_port_tx_flags() 896 * 897 * @UART_TX_NOSTOP: don't call port->ops->stop_tx() on empty buffer 898 */ 899 enum UART_TX_FLAGS { 900 UART_TX_NOSTOP = BIT(0), 901 }; 902 903 #define __uart_port_tx(uport, ch, flags, tx_ready, put_char, tx_done, \ 904 for_test, for_post) \ 905 ({ \ 906 struct uart_port *__port = (uport); \ 907 struct tty_port *__tport = &__port->state->port; \ 908 unsigned int pending; \ 909 \ 910 for (; (for_test) && (tx_ready); (for_post), __port->icount.tx++) { \ 911 if (__port->x_char) { \ 912 (ch) = __port->x_char; \ 913 (put_char); \ 914 __port->x_char = 0; \ 915 continue; \ 916 } \ 917 \ 918 if (uart_tx_stopped(__port)) \ 919 break; \ 920 \ 921 if (!kfifo_get(&__tport->xmit_fifo, &(ch))) \ 922 break; \ 923 \ 924 (put_char); \ 925 } \ 926 \ 927 (tx_done); \ 928 \ 929 pending = kfifo_len(&__tport->xmit_fifo); \ 930 if (pending < WAKEUP_CHARS) { \ 931 uart_write_wakeup(__port); \ 932 \ 933 if (!((flags) & UART_TX_NOSTOP) && pending == 0) \ 934 __port->ops->stop_tx(__port); \ 935 } \ 936 \ 937 pending; \ 938 }) 939 940 /** 941 * uart_port_tx_limited -- transmit helper for uart_port with count limiting 942 * @port: uart port 943 * @ch: variable to store a character to be written to the HW 944 * @count: a limit of characters to send 945 * @tx_ready: can HW accept more data function 946 * @put_char: function to write a character 947 * @tx_done: function to call after the loop is done 948 * 949 * This helper transmits characters from the xmit buffer to the hardware using 950 * @put_char(). It does so until @count characters are sent and while @tx_ready 951 * evaluates to true. 952 * 953 * Returns: the number of characters in the xmit buffer when done. 954 * 955 * The expression in macro parameters shall be designed as follows: 956 * * **tx_ready:** should evaluate to true if the HW can accept more data to 957 * be sent. This parameter can be %true, which means the HW is always ready. 958 * * **put_char:** shall write @ch to the device of @port. 959 * * **tx_done:** when the write loop is done, this can perform arbitrary 960 * action before potential invocation of ops->stop_tx() happens. If the 961 * driver does not need to do anything, use e.g. ({}). 962 * 963 * For all of them, @port->lock is held, interrupts are locally disabled and 964 * the expressions must not sleep. 965 */ 966 #define uart_port_tx_limited(port, ch, count, tx_ready, put_char, tx_done) ({ \ 967 unsigned int __count = (count); \ 968 __uart_port_tx(port, ch, 0, tx_ready, put_char, tx_done, __count, \ 969 __count--); \ 970 }) 971 972 /** 973 * uart_port_tx_limited_flags -- transmit helper for uart_port with count limiting with flags 974 * @port: uart port 975 * @ch: variable to store a character to be written to the HW 976 * @flags: %UART_TX_NOSTOP or similar 977 * @count: a limit of characters to send 978 * @tx_ready: can HW accept more data function 979 * @put_char: function to write a character 980 * @tx_done: function to call after the loop is done 981 * 982 * See uart_port_tx_limited() for more details. 983 */ 984 #define uart_port_tx_limited_flags(port, ch, flags, count, tx_ready, put_char, tx_done) ({ \ 985 unsigned int __count = (count); \ 986 __uart_port_tx(port, ch, flags, tx_ready, put_char, tx_done, __count, \ 987 __count--); \ 988 }) 989 990 /** 991 * uart_port_tx -- transmit helper for uart_port 992 * @port: uart port 993 * @ch: variable to store a character to be written to the HW 994 * @tx_ready: can HW accept more data function 995 * @put_char: function to write a character 996 * 997 * See uart_port_tx_limited() for more details. 998 */ 999 #define uart_port_tx(port, ch, tx_ready, put_char) \ 1000 __uart_port_tx(port, ch, 0, tx_ready, put_char, ({}), true, ({})) 1001 1002 1003 /** 1004 * uart_port_tx_flags -- transmit helper for uart_port with flags 1005 * @port: uart port 1006 * @ch: variable to store a character to be written to the HW 1007 * @flags: %UART_TX_NOSTOP or similar 1008 * @tx_ready: can HW accept more data function 1009 * @put_char: function to write a character 1010 * 1011 * See uart_port_tx_limited() for more details. 1012 */ 1013 #define uart_port_tx_flags(port, ch, flags, tx_ready, put_char) \ 1014 __uart_port_tx(port, ch, flags, tx_ready, put_char, ({}), true, ({})) 1015 /* 1016 * Baud rate helpers. 1017 */ 1018 void uart_update_timeout(struct uart_port *port, unsigned int cflag, 1019 unsigned int baud); 1020 unsigned int uart_get_baud_rate(struct uart_port *port, struct ktermios *termios, 1021 const struct ktermios *old, unsigned int min, 1022 unsigned int max); 1023 unsigned int uart_get_divisor(struct uart_port *port, unsigned int baud); 1024 1025 /* 1026 * Calculates FIFO drain time. 1027 */ 1028 static inline unsigned long uart_fifo_timeout(struct uart_port *port) 1029 { 1030 u64 fifo_timeout = (u64)READ_ONCE(port->frame_time) * port->fifosize; 1031 1032 /* Add .02 seconds of slop */ 1033 fifo_timeout += 20 * NSEC_PER_MSEC; 1034 1035 return max(nsecs_to_jiffies(fifo_timeout), 1UL); 1036 } 1037 1038 /* Base timer interval for polling */ 1039 static inline unsigned long uart_poll_timeout(struct uart_port *port) 1040 { 1041 unsigned long timeout = uart_fifo_timeout(port); 1042 1043 return timeout > 6 ? (timeout / 2 - 2) : 1; 1044 } 1045 1046 /* 1047 * Console helpers. 1048 */ 1049 struct earlycon_device { 1050 struct console *con; 1051 struct uart_port port; 1052 char options[32]; /* e.g., 115200n8 */ 1053 unsigned int baud; 1054 }; 1055 1056 struct earlycon_id { 1057 char name[15]; 1058 char name_term; /* In case compiler didn't '\0' term name */ 1059 char compatible[128]; 1060 int (*setup)(struct earlycon_device *, const char *options); 1061 }; 1062 1063 extern const struct earlycon_id __earlycon_table[]; 1064 extern const struct earlycon_id __earlycon_table_end[]; 1065 1066 #if defined(CONFIG_SERIAL_EARLYCON) && !defined(MODULE) 1067 #define EARLYCON_USED_OR_UNUSED __used 1068 #else 1069 #define EARLYCON_USED_OR_UNUSED __maybe_unused 1070 #endif 1071 1072 #define OF_EARLYCON_DECLARE(_name, compat, fn) \ 1073 static const struct earlycon_id __UNIQUE_ID(__earlycon_##_name) \ 1074 EARLYCON_USED_OR_UNUSED __section("__earlycon_table") \ 1075 __aligned(__alignof__(struct earlycon_id)) \ 1076 = { .name = __stringify(_name), \ 1077 .compatible = compat, \ 1078 .setup = fn } 1079 1080 #define EARLYCON_DECLARE(_name, fn) OF_EARLYCON_DECLARE(_name, "", fn) 1081 1082 int of_setup_earlycon(const struct earlycon_id *match, unsigned long node, 1083 const char *options); 1084 1085 #ifdef CONFIG_SERIAL_EARLYCON 1086 extern bool earlycon_acpi_spcr_enable __initdata; 1087 int setup_earlycon(char *buf); 1088 #else 1089 static const bool earlycon_acpi_spcr_enable EARLYCON_USED_OR_UNUSED; 1090 static inline int setup_earlycon(char *buf) { return 0; } 1091 #endif 1092 1093 /* Variant of uart_console_registered() when the console_list_lock is held. */ 1094 static inline bool uart_console_registered_locked(struct uart_port *port) 1095 { 1096 return uart_console(port) && console_is_registered_locked(port->cons); 1097 } 1098 1099 static inline bool uart_console_registered(struct uart_port *port) 1100 { 1101 return uart_console(port) && console_is_registered(port->cons); 1102 } 1103 1104 int uart_parse_earlycon(char *p, enum uart_iotype *iotype, 1105 resource_size_t *addr, char **options); 1106 void uart_parse_options(const char *options, int *baud, int *parity, int *bits, 1107 int *flow); 1108 int uart_set_options(struct uart_port *port, struct console *co, int baud, 1109 int parity, int bits, int flow); 1110 struct tty_driver *uart_console_device(struct console *co, int *index); 1111 void uart_console_write(struct uart_port *port, const char *s, 1112 unsigned int count, 1113 void (*putchar)(struct uart_port *, unsigned char)); 1114 1115 /* 1116 * Port/driver registration/removal 1117 */ 1118 int uart_register_driver(struct uart_driver *uart); 1119 void uart_unregister_driver(struct uart_driver *uart); 1120 int uart_add_one_port(struct uart_driver *reg, struct uart_port *port); 1121 void uart_remove_one_port(struct uart_driver *reg, struct uart_port *port); 1122 int uart_read_port_properties(struct uart_port *port); 1123 int uart_read_and_validate_port_properties(struct uart_port *port); 1124 bool uart_match_port(const struct uart_port *port1, 1125 const struct uart_port *port2); 1126 1127 /* 1128 * Power Management 1129 */ 1130 int uart_suspend_port(struct uart_driver *reg, struct uart_port *port); 1131 int uart_resume_port(struct uart_driver *reg, struct uart_port *port); 1132 1133 static inline int uart_tx_stopped(struct uart_port *port) 1134 { 1135 struct tty_struct *tty = port->state->port.tty; 1136 if ((tty && tty->flow.stopped) || port->hw_stopped) 1137 return 1; 1138 return 0; 1139 } 1140 1141 static inline bool uart_cts_enabled(struct uart_port *uport) 1142 { 1143 return !!(uport->status & UPSTAT_CTS_ENABLE); 1144 } 1145 1146 static inline bool uart_softcts_mode(struct uart_port *uport) 1147 { 1148 upstat_t mask = UPSTAT_CTS_ENABLE | UPSTAT_AUTOCTS; 1149 1150 return ((uport->status & mask) == UPSTAT_CTS_ENABLE); 1151 } 1152 1153 /* 1154 * The following are helper functions for the low level drivers. 1155 */ 1156 1157 void uart_handle_dcd_change(struct uart_port *uport, bool active); 1158 void uart_handle_cts_change(struct uart_port *uport, bool active); 1159 1160 void uart_insert_char(struct uart_port *port, unsigned int status, 1161 unsigned int overrun, u8 ch, u8 flag); 1162 1163 void uart_xchar_out(struct uart_port *uport, int offset); 1164 1165 #ifdef CONFIG_MAGIC_SYSRQ_SERIAL 1166 #define SYSRQ_TIMEOUT (HZ * 5) 1167 1168 bool uart_try_toggle_sysrq(struct uart_port *port, u8 ch); 1169 1170 static inline int uart_handle_sysrq_char(struct uart_port *port, u8 ch) 1171 { 1172 if (!port->sysrq) 1173 return 0; 1174 1175 if (ch && time_before(jiffies, port->sysrq)) { 1176 if (sysrq_mask()) { 1177 handle_sysrq(ch); 1178 port->sysrq = 0; 1179 return 1; 1180 } 1181 if (uart_try_toggle_sysrq(port, ch)) 1182 return 1; 1183 } 1184 port->sysrq = 0; 1185 1186 return 0; 1187 } 1188 1189 static inline int uart_prepare_sysrq_char(struct uart_port *port, u8 ch) 1190 { 1191 if (!port->sysrq) 1192 return 0; 1193 1194 if (ch && time_before(jiffies, port->sysrq)) { 1195 if (sysrq_mask()) { 1196 port->sysrq_ch = ch; 1197 port->sysrq = 0; 1198 return 1; 1199 } 1200 if (uart_try_toggle_sysrq(port, ch)) 1201 return 1; 1202 } 1203 port->sysrq = 0; 1204 1205 return 0; 1206 } 1207 1208 static inline void uart_unlock_and_check_sysrq(struct uart_port *port) 1209 { 1210 u8 sysrq_ch; 1211 1212 if (!port->has_sysrq) { 1213 uart_port_unlock(port); 1214 return; 1215 } 1216 1217 sysrq_ch = port->sysrq_ch; 1218 port->sysrq_ch = 0; 1219 1220 uart_port_unlock(port); 1221 1222 if (sysrq_ch) 1223 handle_sysrq(sysrq_ch); 1224 } 1225 1226 static inline void uart_unlock_and_check_sysrq_irqrestore(struct uart_port *port, 1227 unsigned long flags) 1228 { 1229 u8 sysrq_ch; 1230 1231 if (!port->has_sysrq) { 1232 uart_port_unlock_irqrestore(port, flags); 1233 return; 1234 } 1235 1236 sysrq_ch = port->sysrq_ch; 1237 port->sysrq_ch = 0; 1238 1239 uart_port_unlock_irqrestore(port, flags); 1240 1241 if (sysrq_ch) 1242 handle_sysrq(sysrq_ch); 1243 } 1244 #else /* CONFIG_MAGIC_SYSRQ_SERIAL */ 1245 static inline int uart_handle_sysrq_char(struct uart_port *port, u8 ch) 1246 { 1247 return 0; 1248 } 1249 static inline int uart_prepare_sysrq_char(struct uart_port *port, u8 ch) 1250 { 1251 return 0; 1252 } 1253 static inline void uart_unlock_and_check_sysrq(struct uart_port *port) 1254 { 1255 uart_port_unlock(port); 1256 } 1257 static inline void uart_unlock_and_check_sysrq_irqrestore(struct uart_port *port, 1258 unsigned long flags) 1259 { 1260 uart_port_unlock_irqrestore(port, flags); 1261 } 1262 #endif /* CONFIG_MAGIC_SYSRQ_SERIAL */ 1263 1264 /* 1265 * We do the SysRQ and SAK checking like this... 1266 */ 1267 static inline int uart_handle_break(struct uart_port *port) 1268 { 1269 struct uart_state *state = port->state; 1270 1271 if (port->handle_break) 1272 port->handle_break(port); 1273 1274 #ifdef CONFIG_MAGIC_SYSRQ_SERIAL 1275 if (port->has_sysrq && uart_console(port)) { 1276 if (!port->sysrq) { 1277 port->sysrq = jiffies + SYSRQ_TIMEOUT; 1278 return 1; 1279 } 1280 port->sysrq = 0; 1281 } 1282 #endif 1283 if (port->flags & UPF_SAK) 1284 do_SAK(state->port.tty); 1285 return 0; 1286 } 1287 1288 /* 1289 * UART_ENABLE_MS - determine if port should enable modem status irqs 1290 */ 1291 #define UART_ENABLE_MS(port,cflag) ((port)->flags & UPF_HARDPPS_CD || \ 1292 (cflag) & CRTSCTS || \ 1293 !((cflag) & CLOCAL)) 1294 1295 int uart_get_rs485_mode(struct uart_port *port); 1296 #endif /* LINUX_SERIAL_CORE_H */ 1297