1 /* SPDX-License-Identifier: GPL-2.0-or-later */
3 * linux/drivers/char/serial_core.h
5 * Copyright (C) 2000 Deep Blue Solutions Ltd.
7 #ifndef LINUX_SERIAL_CORE_H
8 #define LINUX_SERIAL_CORE_H
10 #include <linux/bitops.h>
11 #include <linux/compiler.h>
12 #include <linux/console.h>
13 #include <linux/interrupt.h>
14 #include <linux/circ_buf.h>
15 #include <linux/spinlock.h>
16 #include <linux/sched.h>
17 #include <linux/tty.h>
18 #include <linux/mutex.h>
19 #include <linux/sysrq.h>
20 #include <uapi/linux/serial_core.h>
22 #ifdef CONFIG_SERIAL_CORE_CONSOLE
23 #define uart_console(port) \
24 ((port)->cons && (port)->cons->index == (port)->line)
26 #define uart_console(port) ({ (void)port; 0; })
35 * struct uart_ops -- interface between serial_core and the driver
37 * This structure describes all the operations that can be done on the
40 * @tx_empty: ``unsigned int ()(struct uart_port *port)``
42 * This function tests whether the transmitter fifo and shifter for the
43 * @port is empty. If it is empty, this function should return
44 * %TIOCSER_TEMT, otherwise return 0. If the port does not support this
45 * operation, then it should return %TIOCSER_TEMT.
48 * Interrupts: caller dependent.
49 * This call must not sleep
51 * @set_mctrl: ``void ()(struct uart_port *port, unsigned int mctrl)``
53 * This function sets the modem control lines for @port to the state
54 * described by @mctrl. The relevant bits of @mctrl are:
56 * - %TIOCM_RTS RTS signal.
57 * - %TIOCM_DTR DTR signal.
58 * - %TIOCM_OUT1 OUT1 signal.
59 * - %TIOCM_OUT2 OUT2 signal.
60 * - %TIOCM_LOOP Set the port into loopback mode.
62 * If the appropriate bit is set, the signal should be driven
63 * active. If the bit is clear, the signal should be driven
66 * Locking: @port->lock taken.
67 * Interrupts: locally disabled.
68 * This call must not sleep
70 * @get_mctrl: ``unsigned int ()(struct uart_port *port)``
72 * Returns the current state of modem control inputs of @port. The state
73 * of the outputs should not be returned, since the core keeps track of
74 * their state. The state information should include:
76 * - %TIOCM_CAR state of DCD signal
77 * - %TIOCM_CTS state of CTS signal
78 * - %TIOCM_DSR state of DSR signal
79 * - %TIOCM_RI state of RI signal
81 * The bit is set if the signal is currently driven active. If
82 * the port does not support CTS, DCD or DSR, the driver should
83 * indicate that the signal is permanently active. If RI is
84 * not available, the signal should not be indicated as active.
86 * Locking: @port->lock taken.
87 * Interrupts: locally disabled.
88 * This call must not sleep
90 * @stop_tx: ``void ()(struct uart_port *port)``
92 * Stop transmitting characters. This might be due to the CTS line
93 * becoming inactive or the tty layer indicating we want to stop
94 * transmission due to an %XOFF character.
96 * The driver should stop transmitting characters as soon as possible.
98 * Locking: @port->lock taken.
99 * Interrupts: locally disabled.
100 * This call must not sleep
102 * @start_tx: ``void ()(struct uart_port *port)``
104 * Start transmitting characters.
106 * Locking: @port->lock taken.
107 * Interrupts: locally disabled.
108 * This call must not sleep
110 * @throttle: ``void ()(struct uart_port *port)``
112 * Notify the serial driver that input buffers for the line discipline are
113 * close to full, and it should somehow signal that no more characters
114 * should be sent to the serial port.
115 * This will be called only if hardware assisted flow control is enabled.
117 * Locking: serialized with @unthrottle() and termios modification by the
120 * @unthrottle: ``void ()(struct uart_port *port)``
122 * Notify the serial driver that characters can now be sent to the serial
123 * port without fear of overrunning the input buffers of the line
126 * This will be called only if hardware assisted flow control is enabled.
128 * Locking: serialized with @throttle() and termios modification by the
131 * @send_xchar: ``void ()(struct uart_port *port, char ch)``
133 * Transmit a high priority character, even if the port is stopped. This
134 * is used to implement XON/XOFF flow control and tcflow(). If the serial
135 * driver does not implement this function, the tty core will append the
136 * character to the circular buffer and then call start_tx() / stop_tx()
137 * to flush the data out.
139 * Do not transmit if @ch == '\0' (%__DISABLED_CHAR).
142 * Interrupts: caller dependent.
144 * @start_rx: ``void ()(struct uart_port *port)``
146 * Start receiving characters.
148 * Locking: @port->lock taken.
149 * Interrupts: locally disabled.
150 * This call must not sleep
152 * @stop_rx: ``void ()(struct uart_port *port)``
154 * Stop receiving characters; the @port is in the process of being closed.
156 * Locking: @port->lock taken.
157 * Interrupts: locally disabled.
158 * This call must not sleep
160 * @enable_ms: ``void ()(struct uart_port *port)``
162 * Enable the modem status interrupts.
164 * This method may be called multiple times. Modem status interrupts
165 * should be disabled when the @shutdown() method is called.
167 * Locking: @port->lock taken.
168 * Interrupts: locally disabled.
169 * This call must not sleep
171 * @break_ctl: ``void ()(struct uart_port *port, int ctl)``
173 * Control the transmission of a break signal. If @ctl is nonzero, the
174 * break signal should be transmitted. The signal should be terminated
175 * when another call is made with a zero @ctl.
177 * Locking: caller holds tty_port->mutex
179 * @startup: ``int ()(struct uart_port *port)``
181 * Grab any interrupt resources and initialise any low level driver state.
182 * Enable the port for reception. It should not activate RTS nor DTR;
183 * this will be done via a separate call to @set_mctrl().
185 * This method will only be called when the port is initially opened.
187 * Locking: port_sem taken.
188 * Interrupts: globally disabled.
190 * @shutdown: ``void ()(struct uart_port *port)``
192 * Disable the @port, disable any break condition that may be in effect,
193 * and free any interrupt resources. It should not disable RTS nor DTR;
194 * this will have already been done via a separate call to @set_mctrl().
196 * Drivers must not access @port->state once this call has completed.
198 * This method will only be called when there are no more users of this
201 * Locking: port_sem taken.
202 * Interrupts: caller dependent.
204 * @flush_buffer: ``void ()(struct uart_port *port)``
206 * Flush any write buffers, reset any DMA state and stop any ongoing DMA
209 * This will be called whenever the @port->state->xmit circular buffer is
212 * Locking: @port->lock taken.
213 * Interrupts: locally disabled.
214 * This call must not sleep
216 * @set_termios: ``void ()(struct uart_port *port, struct ktermios *new,
217 * struct ktermios *old)``
219 * Change the @port parameters, including word length, parity, stop bits.
220 * Update @port->read_status_mask and @port->ignore_status_mask to
221 * indicate the types of events we are interested in receiving. Relevant
222 * ktermios::c_cflag bits are:
224 * - %CSIZE - word size
225 * - %CSTOPB - 2 stop bits
226 * - %PARENB - parity enable
227 * - %PARODD - odd parity (when %PARENB is in force)
228 * - %ADDRB - address bit (changed through uart_port::rs485_config()).
229 * - %CREAD - enable reception of characters (if not set, still receive
230 * characters from the port, but throw them away).
231 * - %CRTSCTS - if set, enable CTS status change reporting.
232 * - %CLOCAL - if not set, enable modem status change reporting.
234 * Relevant ktermios::c_iflag bits are:
236 * - %INPCK - enable frame and parity error events to be passed to the TTY
238 * - %BRKINT / %PARMRK - both of these enable break events to be passed to
240 * - %IGNPAR - ignore parity and framing errors.
241 * - %IGNBRK - ignore break errors. If %IGNPAR is also set, ignore overrun
244 * The interaction of the ktermios::c_iflag bits is as follows (parity
245 * error given as an example):
247 * ============ ======= ======= =========================================
248 * Parity error INPCK IGNPAR
249 * ============ ======= ======= =========================================
250 * n/a 0 n/a character received, marked as %TTY_NORMAL
251 * None 1 n/a character received, marked as %TTY_NORMAL
252 * Yes 1 0 character received, marked as %TTY_PARITY
253 * Yes 1 1 character discarded
254 * ============ ======= ======= =========================================
256 * Other flags may be used (eg, xon/xoff characters) if your hardware
257 * supports hardware "soft" flow control.
259 * Locking: caller holds tty_port->mutex
260 * Interrupts: caller dependent.
261 * This call must not sleep
263 * @set_ldisc: ``void ()(struct uart_port *port, struct ktermios *termios)``
265 * Notifier for discipline change. See
266 * Documentation/driver-api/tty/tty_ldisc.rst.
268 * Locking: caller holds tty_port->mutex
270 * @pm: ``void ()(struct uart_port *port, unsigned int state,
271 * unsigned int oldstate)``
273 * Perform any power management related activities on the specified @port.
274 * @state indicates the new state (defined by enum uart_pm_state),
275 * @oldstate indicates the previous state.
277 * This function should not be used to grab any resources.
279 * This will be called when the @port is initially opened and finally
280 * closed, except when the @port is also the system console. This will
281 * occur even if %CONFIG_PM is not set.
284 * Interrupts: caller dependent.
286 * @type: ``const char *()(struct uart_port *port)``
288 * Return a pointer to a string constant describing the specified @port,
289 * or return %NULL, in which case the string 'unknown' is substituted.
292 * Interrupts: caller dependent.
294 * @release_port: ``void ()(struct uart_port *port)``
296 * Release any memory and IO region resources currently in use by the
300 * Interrupts: caller dependent.
302 * @request_port: ``int ()(struct uart_port *port)``
304 * Request any memory and IO region resources required by the port. If any
305 * fail, no resources should be registered when this function returns, and
306 * it should return -%EBUSY on failure.
309 * Interrupts: caller dependent.
311 * @config_port: ``void ()(struct uart_port *port, int type)``
313 * Perform any autoconfiguration steps required for the @port. @type
314 * contains a bit mask of the required configuration. %UART_CONFIG_TYPE
315 * indicates that the port requires detection and identification.
316 * @port->type should be set to the type found, or %PORT_UNKNOWN if no
319 * %UART_CONFIG_IRQ indicates autoconfiguration of the interrupt signal,
320 * which should be probed using standard kernel autoprobing techniques.
321 * This is not necessary on platforms where ports have interrupts
322 * internally hard wired (eg, system on a chip implementations).
325 * Interrupts: caller dependent.
327 * @verify_port: ``int ()(struct uart_port *port,
328 * struct serial_struct *serinfo)``
330 * Verify the new serial port information contained within @serinfo is
331 * suitable for this port type.
334 * Interrupts: caller dependent.
336 * @ioctl: ``int ()(struct uart_port *port, unsigned int cmd,
337 * unsigned long arg)``
339 * Perform any port specific IOCTLs. IOCTL commands must be defined using
340 * the standard numbering system found in <asm/ioctl.h>.
343 * Interrupts: caller dependent.
345 * @poll_init: ``int ()(struct uart_port *port)``
347 * Called by kgdb to perform the minimal hardware initialization needed to
348 * support @poll_put_char() and @poll_get_char(). Unlike @startup(), this
349 * should not request interrupts.
351 * Locking: %tty_mutex and tty_port->mutex taken.
354 * @poll_put_char: ``void ()(struct uart_port *port, unsigned char ch)``
356 * Called by kgdb to write a single character @ch directly to the serial
357 * @port. It can and should block until there is space in the TX FIFO.
360 * Interrupts: caller dependent.
361 * This call must not sleep
363 * @poll_get_char: ``int ()(struct uart_port *port)``
365 * Called by kgdb to read a single character directly from the serial
366 * port. If data is available, it should be returned; otherwise the
367 * function should return %NO_POLL_CHAR immediately.
370 * Interrupts: caller dependent.
371 * This call must not sleep
374 unsigned int (*tx_empty)(struct uart_port *);
375 void (*set_mctrl)(struct uart_port *, unsigned int mctrl);
376 unsigned int (*get_mctrl)(struct uart_port *);
377 void (*stop_tx)(struct uart_port *);
378 void (*start_tx)(struct uart_port *);
379 void (*throttle)(struct uart_port *);
380 void (*unthrottle)(struct uart_port *);
381 void (*send_xchar)(struct uart_port *, char ch);
382 void (*stop_rx)(struct uart_port *);
383 void (*start_rx)(struct uart_port *);
384 void (*enable_ms)(struct uart_port *);
385 void (*break_ctl)(struct uart_port *, int ctl);
386 int (*startup)(struct uart_port *);
387 void (*shutdown)(struct uart_port *);
388 void (*flush_buffer)(struct uart_port *);
389 void (*set_termios)(struct uart_port *, struct ktermios *new,
390 const struct ktermios *old);
391 void (*set_ldisc)(struct uart_port *, struct ktermios *);
392 void (*pm)(struct uart_port *, unsigned int state,
393 unsigned int oldstate);
394 const char *(*type)(struct uart_port *);
395 void (*release_port)(struct uart_port *);
396 int (*request_port)(struct uart_port *);
397 void (*config_port)(struct uart_port *, int);
398 int (*verify_port)(struct uart_port *, struct serial_struct *);
399 int (*ioctl)(struct uart_port *, unsigned int, unsigned long);
400 #ifdef CONFIG_CONSOLE_POLL
401 int (*poll_init)(struct uart_port *);
402 void (*poll_put_char)(struct uart_port *, unsigned char);
403 int (*poll_get_char)(struct uart_port *);
407 #define NO_POLL_CHAR 0x00ff0000
408 #define UART_CONFIG_TYPE (1 << 0)
409 #define UART_CONFIG_IRQ (1 << 1)
425 typedef u64 __bitwise upf_t;
426 typedef unsigned int __bitwise upstat_t;
429 spinlock_t lock; /* port lock */
430 unsigned long iobase; /* in/out[bwl] */
431 unsigned char __iomem *membase; /* read/write[bwl] */
432 unsigned int (*serial_in)(struct uart_port *, int);
433 void (*serial_out)(struct uart_port *, int, int);
434 void (*set_termios)(struct uart_port *,
435 struct ktermios *new,
436 const struct ktermios *old);
437 void (*set_ldisc)(struct uart_port *,
439 unsigned int (*get_mctrl)(struct uart_port *);
440 void (*set_mctrl)(struct uart_port *, unsigned int);
441 unsigned int (*get_divisor)(struct uart_port *,
444 void (*set_divisor)(struct uart_port *,
447 unsigned int quot_frac);
448 int (*startup)(struct uart_port *port);
449 void (*shutdown)(struct uart_port *port);
450 void (*throttle)(struct uart_port *port);
451 void (*unthrottle)(struct uart_port *port);
452 int (*handle_irq)(struct uart_port *);
453 void (*pm)(struct uart_port *, unsigned int state,
455 void (*handle_break)(struct uart_port *);
456 int (*rs485_config)(struct uart_port *,
457 struct ktermios *termios,
458 struct serial_rs485 *rs485);
459 int (*iso7816_config)(struct uart_port *,
460 struct serial_iso7816 *iso7816);
461 unsigned int irq; /* irq number */
462 unsigned long irqflags; /* irq flags */
463 unsigned int uartclk; /* base uart clock */
464 unsigned int fifosize; /* tx fifo size */
465 unsigned char x_char; /* xon/xoff char */
466 unsigned char regshift; /* reg offset shift */
467 unsigned char iotype; /* io access style */
468 unsigned char quirks; /* internal quirks */
470 #define UPIO_PORT (SERIAL_IO_PORT) /* 8b I/O port access */
471 #define UPIO_HUB6 (SERIAL_IO_HUB6) /* Hub6 ISA card */
472 #define UPIO_MEM (SERIAL_IO_MEM) /* driver-specific */
473 #define UPIO_MEM32 (SERIAL_IO_MEM32) /* 32b little endian */
474 #define UPIO_AU (SERIAL_IO_AU) /* Au1x00 and RT288x type IO */
475 #define UPIO_TSI (SERIAL_IO_TSI) /* Tsi108/109 type IO */
476 #define UPIO_MEM32BE (SERIAL_IO_MEM32BE) /* 32b big endian */
477 #define UPIO_MEM16 (SERIAL_IO_MEM16) /* 16b little endian */
479 /* quirks must be updated while holding port mutex */
480 #define UPQ_NO_TXEN_TEST BIT(0)
482 unsigned int read_status_mask; /* driver specific */
483 unsigned int ignore_status_mask; /* driver specific */
484 struct uart_state *state; /* pointer to parent state */
485 struct uart_icount icount; /* statistics */
487 struct console *cons; /* struct console, if any */
488 /* flags must be updated while holding port mutex */
492 * These flags must be equivalent to the flags defined in
493 * include/uapi/linux/tty_flags.h which are the userspace definitions
494 * assigned from the serial_struct flags in uart_set_info()
495 * [for bit definitions in the UPF_CHANGE_MASK]
497 * Bits [0..ASYNCB_LAST_USER] are userspace defined/visible/changeable
498 * The remaining bits are serial-core specific and not modifiable by
501 #define UPF_FOURPORT ((__force upf_t) ASYNC_FOURPORT /* 1 */ )
502 #define UPF_SAK ((__force upf_t) ASYNC_SAK /* 2 */ )
503 #define UPF_SPD_HI ((__force upf_t) ASYNC_SPD_HI /* 4 */ )
504 #define UPF_SPD_VHI ((__force upf_t) ASYNC_SPD_VHI /* 5 */ )
505 #define UPF_SPD_CUST ((__force upf_t) ASYNC_SPD_CUST /* 0x0030 */ )
506 #define UPF_SPD_WARP ((__force upf_t) ASYNC_SPD_WARP /* 0x1010 */ )
507 #define UPF_SPD_MASK ((__force upf_t) ASYNC_SPD_MASK /* 0x1030 */ )
508 #define UPF_SKIP_TEST ((__force upf_t) ASYNC_SKIP_TEST /* 6 */ )
509 #define UPF_AUTO_IRQ ((__force upf_t) ASYNC_AUTO_IRQ /* 7 */ )
510 #define UPF_HARDPPS_CD ((__force upf_t) ASYNC_HARDPPS_CD /* 11 */ )
511 #define UPF_SPD_SHI ((__force upf_t) ASYNC_SPD_SHI /* 12 */ )
512 #define UPF_LOW_LATENCY ((__force upf_t) ASYNC_LOW_LATENCY /* 13 */ )
513 #define UPF_BUGGY_UART ((__force upf_t) ASYNC_BUGGY_UART /* 14 */ )
514 #define UPF_MAGIC_MULTIPLIER ((__force upf_t) ASYNC_MAGIC_MULTIPLIER /* 16 */ )
516 #define UPF_NO_THRE_TEST ((__force upf_t) BIT_ULL(19))
517 /* Port has hardware-assisted h/w flow control */
518 #define UPF_AUTO_CTS ((__force upf_t) BIT_ULL(20))
519 #define UPF_AUTO_RTS ((__force upf_t) BIT_ULL(21))
520 #define UPF_HARD_FLOW ((__force upf_t) (UPF_AUTO_CTS | UPF_AUTO_RTS))
521 /* Port has hardware-assisted s/w flow control */
522 #define UPF_SOFT_FLOW ((__force upf_t) BIT_ULL(22))
523 #define UPF_CONS_FLOW ((__force upf_t) BIT_ULL(23))
524 #define UPF_SHARE_IRQ ((__force upf_t) BIT_ULL(24))
525 #define UPF_EXAR_EFR ((__force upf_t) BIT_ULL(25))
526 #define UPF_BUG_THRE ((__force upf_t) BIT_ULL(26))
527 /* The exact UART type is known and should not be probed. */
528 #define UPF_FIXED_TYPE ((__force upf_t) BIT_ULL(27))
529 #define UPF_BOOT_AUTOCONF ((__force upf_t) BIT_ULL(28))
530 #define UPF_FIXED_PORT ((__force upf_t) BIT_ULL(29))
531 #define UPF_DEAD ((__force upf_t) BIT_ULL(30))
532 #define UPF_IOREMAP ((__force upf_t) BIT_ULL(31))
533 #define UPF_FULL_PROBE ((__force upf_t) BIT_ULL(32))
535 #define __UPF_CHANGE_MASK 0x17fff
536 #define UPF_CHANGE_MASK ((__force upf_t) __UPF_CHANGE_MASK)
537 #define UPF_USR_MASK ((__force upf_t) (UPF_SPD_MASK|UPF_LOW_LATENCY))
539 #if __UPF_CHANGE_MASK > ASYNC_FLAGS
540 #error Change mask not equivalent to userspace-visible bit defines
544 * Must hold termios_rwsem, port mutex and port lock to change;
545 * can hold any one lock to read.
549 #define UPSTAT_CTS_ENABLE ((__force upstat_t) (1 << 0))
550 #define UPSTAT_DCD_ENABLE ((__force upstat_t) (1 << 1))
551 #define UPSTAT_AUTORTS ((__force upstat_t) (1 << 2))
552 #define UPSTAT_AUTOCTS ((__force upstat_t) (1 << 3))
553 #define UPSTAT_AUTOXOFF ((__force upstat_t) (1 << 4))
554 #define UPSTAT_SYNC_FIFO ((__force upstat_t) (1 << 5))
556 bool hw_stopped; /* sw-assisted CTS flow state */
557 unsigned int mctrl; /* current modem ctrl settings */
558 unsigned int frame_time; /* frame timing in ns */
559 unsigned int type; /* port type */
560 const struct uart_ops *ops;
561 unsigned int custom_divisor;
562 unsigned int line; /* port index */
564 resource_size_t mapbase; /* for ioremap */
565 resource_size_t mapsize;
566 struct device *dev; /* parent device */
568 unsigned long sysrq; /* sysrq timeout */
569 unsigned int sysrq_ch; /* char for sysrq */
570 unsigned char has_sysrq;
571 unsigned char sysrq_seq; /* index in sysrq_toggle_seq */
573 unsigned char hub6; /* this should be in the 8250 driver */
574 unsigned char suspended;
575 unsigned char console_reinit;
576 const char *name; /* port name */
577 struct attribute_group *attr_group; /* port specific attributes */
578 const struct attribute_group **tty_groups; /* all attributes (serial core use only) */
579 struct serial_rs485 rs485;
580 struct serial_rs485 rs485_supported; /* Supported mask for serial_rs485 */
581 struct gpio_desc *rs485_term_gpio; /* enable RS485 bus termination */
582 struct gpio_desc *rs485_rx_during_tx_gpio; /* Output GPIO that sets the state of RS485 RX during TX */
583 struct serial_iso7816 iso7816;
584 void *private_data; /* generic platform data pointer */
587 static inline int serial_port_in(struct uart_port *up, int offset)
589 return up->serial_in(up, offset);
592 static inline void serial_port_out(struct uart_port *up, int offset, int value)
594 up->serial_out(up, offset, value);
598 * enum uart_pm_state - power states for UARTs
599 * @UART_PM_STATE_ON: UART is powered, up and operational
600 * @UART_PM_STATE_OFF: UART is powered off
601 * @UART_PM_STATE_UNDEFINED: sentinel
604 UART_PM_STATE_ON = 0,
605 UART_PM_STATE_OFF = 3, /* number taken from ACPI */
606 UART_PM_STATE_UNDEFINED,
610 * This is the state information which is persistent across opens.
613 struct tty_port port;
615 enum uart_pm_state pm_state;
616 struct circ_buf xmit;
619 wait_queue_head_t remove_wait;
620 struct uart_port *uart_port;
623 #define UART_XMIT_SIZE PAGE_SIZE
626 /* number of characters left in xmit buffer before we ask for more */
627 #define WAKEUP_CHARS 256
630 * uart_xmit_advance - Advance xmit buffer and account Tx'ed chars
631 * @up: uart_port structure describing the port
632 * @chars: number of characters sent
634 * This function advances the tail of circular xmit buffer by the number of
635 * @chars transmitted and handles accounting of transmitted bytes (into
638 static inline void uart_xmit_advance(struct uart_port *up, unsigned int chars)
640 struct circ_buf *xmit = &up->state->xmit;
642 xmit->tail = (xmit->tail + chars) & (UART_XMIT_SIZE - 1);
643 up->icount.tx += chars;
650 struct module *owner;
651 const char *driver_name;
652 const char *dev_name;
656 struct console *cons;
659 * these are private; the low level driver should not
660 * touch these; they should be initialised to NULL
662 struct uart_state *state;
663 struct tty_driver *tty_driver;
666 void uart_write_wakeup(struct uart_port *port);
668 #define __uart_port_tx(uport, ch, tx_ready, put_char, tx_done, for_test, \
671 struct uart_port *__port = (uport); \
672 struct circ_buf *xmit = &__port->state->xmit; \
673 unsigned int pending; \
675 for (; (for_test) && (tx_ready); (for_post), __port->icount.tx++) { \
676 if (__port->x_char) { \
677 (ch) = __port->x_char; \
679 __port->x_char = 0; \
683 if (uart_circ_empty(xmit) || uart_tx_stopped(__port)) \
686 (ch) = xmit->buf[xmit->tail]; \
688 xmit->tail = (xmit->tail + 1) % UART_XMIT_SIZE; \
693 pending = uart_circ_chars_pending(xmit); \
694 if (pending < WAKEUP_CHARS) { \
695 uart_write_wakeup(__port); \
698 __port->ops->stop_tx(__port); \
705 * uart_port_tx_limited -- transmit helper for uart_port with count limiting
707 * @ch: variable to store a character to be written to the HW
708 * @count: a limit of characters to send
709 * @tx_ready: can HW accept more data function
710 * @put_char: function to write a character
711 * @tx_done: function to call after the loop is done
713 * This helper transmits characters from the xmit buffer to the hardware using
714 * @put_char(). It does so until @count characters are sent and while @tx_ready
717 * Returns: the number of characters in the xmit buffer when done.
719 * The expression in macro parameters shall be designed as follows:
720 * * **tx_ready:** should evaluate to true if the HW can accept more data to
721 * be sent. This parameter can be %true, which means the HW is always ready.
722 * * **put_char:** shall write @ch to the device of @port.
723 * * **tx_done:** when the write loop is done, this can perform arbitrary
724 * action before potential invocation of ops->stop_tx() happens. If the
725 * driver does not need to do anything, use e.g. ({}).
727 * For all of them, @port->lock is held, interrupts are locally disabled and
728 * the expressions must not sleep.
730 #define uart_port_tx_limited(port, ch, count, tx_ready, put_char, tx_done) ({ \
731 unsigned int __count = (count); \
732 __uart_port_tx(port, ch, tx_ready, put_char, tx_done, __count, \
737 * uart_port_tx -- transmit helper for uart_port
739 * @ch: variable to store a character to be written to the HW
740 * @tx_ready: can HW accept more data function
741 * @put_char: function to write a character
743 * See uart_port_tx_limited() for more details.
745 #define uart_port_tx(port, ch, tx_ready, put_char) \
746 __uart_port_tx(port, ch, tx_ready, put_char, ({}), true, ({}))
751 void uart_update_timeout(struct uart_port *port, unsigned int cflag,
753 unsigned int uart_get_baud_rate(struct uart_port *port, struct ktermios *termios,
754 const struct ktermios *old, unsigned int min,
756 unsigned int uart_get_divisor(struct uart_port *port, unsigned int baud);
759 * Calculates FIFO drain time.
761 static inline unsigned long uart_fifo_timeout(struct uart_port *port)
763 u64 fifo_timeout = (u64)READ_ONCE(port->frame_time) * port->fifosize;
765 /* Add .02 seconds of slop */
766 fifo_timeout += 20 * NSEC_PER_MSEC;
768 return max(nsecs_to_jiffies(fifo_timeout), 1UL);
771 /* Base timer interval for polling */
772 static inline int uart_poll_timeout(struct uart_port *port)
774 int timeout = uart_fifo_timeout(port);
776 return timeout > 6 ? (timeout / 2 - 2) : 1;
782 struct earlycon_device {
784 struct uart_port port;
785 char options[32]; /* e.g., 115200n8 */
791 char name_term; /* In case compiler didn't '\0' term name */
792 char compatible[128];
793 int (*setup)(struct earlycon_device *, const char *options);
796 extern const struct earlycon_id __earlycon_table[];
797 extern const struct earlycon_id __earlycon_table_end[];
799 #if defined(CONFIG_SERIAL_EARLYCON) && !defined(MODULE)
800 #define EARLYCON_USED_OR_UNUSED __used
802 #define EARLYCON_USED_OR_UNUSED __maybe_unused
805 #define OF_EARLYCON_DECLARE(_name, compat, fn) \
806 static const struct earlycon_id __UNIQUE_ID(__earlycon_##_name) \
807 EARLYCON_USED_OR_UNUSED __section("__earlycon_table") \
808 __aligned(__alignof__(struct earlycon_id)) \
809 = { .name = __stringify(_name), \
810 .compatible = compat, \
813 #define EARLYCON_DECLARE(_name, fn) OF_EARLYCON_DECLARE(_name, "", fn)
815 int of_setup_earlycon(const struct earlycon_id *match, unsigned long node,
816 const char *options);
818 #ifdef CONFIG_SERIAL_EARLYCON
819 extern bool earlycon_acpi_spcr_enable __initdata;
820 int setup_earlycon(char *buf);
822 static const bool earlycon_acpi_spcr_enable EARLYCON_USED_OR_UNUSED;
823 static inline int setup_earlycon(char *buf) { return 0; }
826 /* Variant of uart_console_registered() when the console_list_lock is held. */
827 static inline bool uart_console_registered_locked(struct uart_port *port)
829 return uart_console(port) && console_is_registered_locked(port->cons);
832 static inline bool uart_console_registered(struct uart_port *port)
834 return uart_console(port) && console_is_registered(port->cons);
837 struct uart_port *uart_get_console(struct uart_port *ports, int nr,
839 int uart_parse_earlycon(char *p, unsigned char *iotype, resource_size_t *addr,
841 void uart_parse_options(const char *options, int *baud, int *parity, int *bits,
843 int uart_set_options(struct uart_port *port, struct console *co, int baud,
844 int parity, int bits, int flow);
845 struct tty_driver *uart_console_device(struct console *co, int *index);
846 void uart_console_write(struct uart_port *port, const char *s,
848 void (*putchar)(struct uart_port *, unsigned char));
851 * Port/driver registration/removal
853 int uart_register_driver(struct uart_driver *uart);
854 void uart_unregister_driver(struct uart_driver *uart);
855 int uart_add_one_port(struct uart_driver *reg, struct uart_port *port);
856 int uart_remove_one_port(struct uart_driver *reg, struct uart_port *port);
857 bool uart_match_port(const struct uart_port *port1,
858 const struct uart_port *port2);
863 int uart_suspend_port(struct uart_driver *reg, struct uart_port *port);
864 int uart_resume_port(struct uart_driver *reg, struct uart_port *port);
866 #define uart_circ_empty(circ) ((circ)->head == (circ)->tail)
867 #define uart_circ_clear(circ) ((circ)->head = (circ)->tail = 0)
869 #define uart_circ_chars_pending(circ) \
870 (CIRC_CNT((circ)->head, (circ)->tail, UART_XMIT_SIZE))
872 #define uart_circ_chars_free(circ) \
873 (CIRC_SPACE((circ)->head, (circ)->tail, UART_XMIT_SIZE))
875 static inline int uart_tx_stopped(struct uart_port *port)
877 struct tty_struct *tty = port->state->port.tty;
878 if ((tty && tty->flow.stopped) || port->hw_stopped)
883 static inline bool uart_cts_enabled(struct uart_port *uport)
885 return !!(uport->status & UPSTAT_CTS_ENABLE);
888 static inline bool uart_softcts_mode(struct uart_port *uport)
890 upstat_t mask = UPSTAT_CTS_ENABLE | UPSTAT_AUTOCTS;
892 return ((uport->status & mask) == UPSTAT_CTS_ENABLE);
896 * The following are helper functions for the low level drivers.
899 void uart_handle_dcd_change(struct uart_port *uport, bool active);
900 void uart_handle_cts_change(struct uart_port *uport, bool active);
902 void uart_insert_char(struct uart_port *port, unsigned int status,
903 unsigned int overrun, unsigned int ch, unsigned int flag);
905 void uart_xchar_out(struct uart_port *uport, int offset);
907 #ifdef CONFIG_MAGIC_SYSRQ_SERIAL
908 #define SYSRQ_TIMEOUT (HZ * 5)
910 bool uart_try_toggle_sysrq(struct uart_port *port, unsigned int ch);
912 static inline int uart_handle_sysrq_char(struct uart_port *port, unsigned int ch)
917 if (ch && time_before(jiffies, port->sysrq)) {
923 if (uart_try_toggle_sysrq(port, ch))
931 static inline int uart_prepare_sysrq_char(struct uart_port *port, unsigned int ch)
936 if (ch && time_before(jiffies, port->sysrq)) {
942 if (uart_try_toggle_sysrq(port, ch))
950 static inline void uart_unlock_and_check_sysrq(struct uart_port *port)
954 if (!port->has_sysrq) {
955 spin_unlock(&port->lock);
959 sysrq_ch = port->sysrq_ch;
962 spin_unlock(&port->lock);
965 handle_sysrq(sysrq_ch);
968 static inline void uart_unlock_and_check_sysrq_irqrestore(struct uart_port *port,
973 if (!port->has_sysrq) {
974 spin_unlock_irqrestore(&port->lock, flags);
978 sysrq_ch = port->sysrq_ch;
981 spin_unlock_irqrestore(&port->lock, flags);
984 handle_sysrq(sysrq_ch);
986 #else /* CONFIG_MAGIC_SYSRQ_SERIAL */
987 static inline int uart_handle_sysrq_char(struct uart_port *port, unsigned int ch)
991 static inline int uart_prepare_sysrq_char(struct uart_port *port, unsigned int ch)
995 static inline void uart_unlock_and_check_sysrq(struct uart_port *port)
997 spin_unlock(&port->lock);
999 static inline void uart_unlock_and_check_sysrq_irqrestore(struct uart_port *port,
1000 unsigned long flags)
1002 spin_unlock_irqrestore(&port->lock, flags);
1004 #endif /* CONFIG_MAGIC_SYSRQ_SERIAL */
1007 * We do the SysRQ and SAK checking like this...
1009 static inline int uart_handle_break(struct uart_port *port)
1011 struct uart_state *state = port->state;
1013 if (port->handle_break)
1014 port->handle_break(port);
1016 #ifdef CONFIG_MAGIC_SYSRQ_SERIAL
1017 if (port->has_sysrq && uart_console(port)) {
1019 port->sysrq = jiffies + SYSRQ_TIMEOUT;
1025 if (port->flags & UPF_SAK)
1026 do_SAK(state->port.tty);
1031 * UART_ENABLE_MS - determine if port should enable modem status irqs
1033 #define UART_ENABLE_MS(port,cflag) ((port)->flags & UPF_HARDPPS_CD || \
1034 (cflag) & CRTSCTS || \
1035 !((cflag) & CLOCAL))
1037 int uart_get_rs485_mode(struct uart_port *port);
1038 #endif /* LINUX_SERIAL_CORE_H */