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; })
31 struct serial_port_device;
36 * struct uart_ops -- interface between serial_core and the driver
38 * This structure describes all the operations that can be done on the
41 * @tx_empty: ``unsigned int ()(struct uart_port *port)``
43 * This function tests whether the transmitter fifo and shifter for the
44 * @port is empty. If it is empty, this function should return
45 * %TIOCSER_TEMT, otherwise return 0. If the port does not support this
46 * operation, then it should return %TIOCSER_TEMT.
49 * Interrupts: caller dependent.
50 * This call must not sleep
52 * @set_mctrl: ``void ()(struct uart_port *port, unsigned int mctrl)``
54 * This function sets the modem control lines for @port to the state
55 * described by @mctrl. The relevant bits of @mctrl are:
57 * - %TIOCM_RTS RTS signal.
58 * - %TIOCM_DTR DTR signal.
59 * - %TIOCM_OUT1 OUT1 signal.
60 * - %TIOCM_OUT2 OUT2 signal.
61 * - %TIOCM_LOOP Set the port into loopback mode.
63 * If the appropriate bit is set, the signal should be driven
64 * active. If the bit is clear, the signal should be driven
67 * Locking: @port->lock taken.
68 * Interrupts: locally disabled.
69 * This call must not sleep
71 * @get_mctrl: ``unsigned int ()(struct uart_port *port)``
73 * Returns the current state of modem control inputs of @port. The state
74 * of the outputs should not be returned, since the core keeps track of
75 * their state. The state information should include:
77 * - %TIOCM_CAR state of DCD signal
78 * - %TIOCM_CTS state of CTS signal
79 * - %TIOCM_DSR state of DSR signal
80 * - %TIOCM_RI state of RI signal
82 * The bit is set if the signal is currently driven active. If
83 * the port does not support CTS, DCD or DSR, the driver should
84 * indicate that the signal is permanently active. If RI is
85 * not available, the signal should not be indicated as active.
87 * Locking: @port->lock taken.
88 * Interrupts: locally disabled.
89 * This call must not sleep
91 * @stop_tx: ``void ()(struct uart_port *port)``
93 * Stop transmitting characters. This might be due to the CTS line
94 * becoming inactive or the tty layer indicating we want to stop
95 * transmission due to an %XOFF character.
97 * The driver should stop transmitting characters as soon as possible.
99 * Locking: @port->lock taken.
100 * Interrupts: locally disabled.
101 * This call must not sleep
103 * @start_tx: ``void ()(struct uart_port *port)``
105 * Start transmitting characters.
107 * Locking: @port->lock taken.
108 * Interrupts: locally disabled.
109 * This call must not sleep
111 * @throttle: ``void ()(struct uart_port *port)``
113 * Notify the serial driver that input buffers for the line discipline are
114 * close to full, and it should somehow signal that no more characters
115 * should be sent to the serial port.
116 * This will be called only if hardware assisted flow control is enabled.
118 * Locking: serialized with @unthrottle() and termios modification by the
121 * @unthrottle: ``void ()(struct uart_port *port)``
123 * Notify the serial driver that characters can now be sent to the serial
124 * port without fear of overrunning the input buffers of the line
127 * This will be called only if hardware assisted flow control is enabled.
129 * Locking: serialized with @throttle() and termios modification by the
132 * @send_xchar: ``void ()(struct uart_port *port, char ch)``
134 * Transmit a high priority character, even if the port is stopped. This
135 * is used to implement XON/XOFF flow control and tcflow(). If the serial
136 * driver does not implement this function, the tty core will append the
137 * character to the circular buffer and then call start_tx() / stop_tx()
138 * to flush the data out.
140 * Do not transmit if @ch == '\0' (%__DISABLED_CHAR).
143 * Interrupts: caller dependent.
145 * @start_rx: ``void ()(struct uart_port *port)``
147 * Start receiving characters.
149 * Locking: @port->lock taken.
150 * Interrupts: locally disabled.
151 * This call must not sleep
153 * @stop_rx: ``void ()(struct uart_port *port)``
155 * Stop receiving characters; the @port is in the process of being closed.
157 * Locking: @port->lock taken.
158 * Interrupts: locally disabled.
159 * This call must not sleep
161 * @enable_ms: ``void ()(struct uart_port *port)``
163 * Enable the modem status interrupts.
165 * This method may be called multiple times. Modem status interrupts
166 * should be disabled when the @shutdown() method is called.
168 * Locking: @port->lock taken.
169 * Interrupts: locally disabled.
170 * This call must not sleep
172 * @break_ctl: ``void ()(struct uart_port *port, int ctl)``
174 * Control the transmission of a break signal. If @ctl is nonzero, the
175 * break signal should be transmitted. The signal should be terminated
176 * when another call is made with a zero @ctl.
178 * Locking: caller holds tty_port->mutex
180 * @startup: ``int ()(struct uart_port *port)``
182 * Grab any interrupt resources and initialise any low level driver state.
183 * Enable the port for reception. It should not activate RTS nor DTR;
184 * this will be done via a separate call to @set_mctrl().
186 * This method will only be called when the port is initially opened.
188 * Locking: port_sem taken.
189 * Interrupts: globally disabled.
191 * @shutdown: ``void ()(struct uart_port *port)``
193 * Disable the @port, disable any break condition that may be in effect,
194 * and free any interrupt resources. It should not disable RTS nor DTR;
195 * this will have already been done via a separate call to @set_mctrl().
197 * Drivers must not access @port->state once this call has completed.
199 * This method will only be called when there are no more users of this
202 * Locking: port_sem taken.
203 * Interrupts: caller dependent.
205 * @flush_buffer: ``void ()(struct uart_port *port)``
207 * Flush any write buffers, reset any DMA state and stop any ongoing DMA
210 * This will be called whenever the @port->state->xmit circular buffer is
213 * Locking: @port->lock taken.
214 * Interrupts: locally disabled.
215 * This call must not sleep
217 * @set_termios: ``void ()(struct uart_port *port, struct ktermios *new,
218 * struct ktermios *old)``
220 * Change the @port parameters, including word length, parity, stop bits.
221 * Update @port->read_status_mask and @port->ignore_status_mask to
222 * indicate the types of events we are interested in receiving. Relevant
223 * ktermios::c_cflag bits are:
225 * - %CSIZE - word size
226 * - %CSTOPB - 2 stop bits
227 * - %PARENB - parity enable
228 * - %PARODD - odd parity (when %PARENB is in force)
229 * - %ADDRB - address bit (changed through uart_port::rs485_config()).
230 * - %CREAD - enable reception of characters (if not set, still receive
231 * characters from the port, but throw them away).
232 * - %CRTSCTS - if set, enable CTS status change reporting.
233 * - %CLOCAL - if not set, enable modem status change reporting.
235 * Relevant ktermios::c_iflag bits are:
237 * - %INPCK - enable frame and parity error events to be passed to the TTY
239 * - %BRKINT / %PARMRK - both of these enable break events to be passed to
241 * - %IGNPAR - ignore parity and framing errors.
242 * - %IGNBRK - ignore break errors. If %IGNPAR is also set, ignore overrun
245 * The interaction of the ktermios::c_iflag bits is as follows (parity
246 * error given as an example):
248 * ============ ======= ======= =========================================
249 * Parity error INPCK IGNPAR
250 * ============ ======= ======= =========================================
251 * n/a 0 n/a character received, marked as %TTY_NORMAL
252 * None 1 n/a character received, marked as %TTY_NORMAL
253 * Yes 1 0 character received, marked as %TTY_PARITY
254 * Yes 1 1 character discarded
255 * ============ ======= ======= =========================================
257 * Other flags may be used (eg, xon/xoff characters) if your hardware
258 * supports hardware "soft" flow control.
260 * Locking: caller holds tty_port->mutex
261 * Interrupts: caller dependent.
262 * This call must not sleep
264 * @set_ldisc: ``void ()(struct uart_port *port, struct ktermios *termios)``
266 * Notifier for discipline change. See
267 * Documentation/driver-api/tty/tty_ldisc.rst.
269 * Locking: caller holds tty_port->mutex
271 * @pm: ``void ()(struct uart_port *port, unsigned int state,
272 * unsigned int oldstate)``
274 * Perform any power management related activities on the specified @port.
275 * @state indicates the new state (defined by enum uart_pm_state),
276 * @oldstate indicates the previous state.
278 * This function should not be used to grab any resources.
280 * This will be called when the @port is initially opened and finally
281 * closed, except when the @port is also the system console. This will
282 * occur even if %CONFIG_PM is not set.
285 * Interrupts: caller dependent.
287 * @type: ``const char *()(struct uart_port *port)``
289 * Return a pointer to a string constant describing the specified @port,
290 * or return %NULL, in which case the string 'unknown' is substituted.
293 * Interrupts: caller dependent.
295 * @release_port: ``void ()(struct uart_port *port)``
297 * Release any memory and IO region resources currently in use by the
301 * Interrupts: caller dependent.
303 * @request_port: ``int ()(struct uart_port *port)``
305 * Request any memory and IO region resources required by the port. If any
306 * fail, no resources should be registered when this function returns, and
307 * it should return -%EBUSY on failure.
310 * Interrupts: caller dependent.
312 * @config_port: ``void ()(struct uart_port *port, int type)``
314 * Perform any autoconfiguration steps required for the @port. @type
315 * contains a bit mask of the required configuration. %UART_CONFIG_TYPE
316 * indicates that the port requires detection and identification.
317 * @port->type should be set to the type found, or %PORT_UNKNOWN if no
320 * %UART_CONFIG_IRQ indicates autoconfiguration of the interrupt signal,
321 * which should be probed using standard kernel autoprobing techniques.
322 * This is not necessary on platforms where ports have interrupts
323 * internally hard wired (eg, system on a chip implementations).
326 * Interrupts: caller dependent.
328 * @verify_port: ``int ()(struct uart_port *port,
329 * struct serial_struct *serinfo)``
331 * Verify the new serial port information contained within @serinfo is
332 * suitable for this port type.
335 * Interrupts: caller dependent.
337 * @ioctl: ``int ()(struct uart_port *port, unsigned int cmd,
338 * unsigned long arg)``
340 * Perform any port specific IOCTLs. IOCTL commands must be defined using
341 * the standard numbering system found in <asm/ioctl.h>.
344 * Interrupts: caller dependent.
346 * @poll_init: ``int ()(struct uart_port *port)``
348 * Called by kgdb to perform the minimal hardware initialization needed to
349 * support @poll_put_char() and @poll_get_char(). Unlike @startup(), this
350 * should not request interrupts.
352 * Locking: %tty_mutex and tty_port->mutex taken.
355 * @poll_put_char: ``void ()(struct uart_port *port, unsigned char ch)``
357 * Called by kgdb to write a single character @ch directly to the serial
358 * @port. It can and should block until there is space in the TX FIFO.
361 * Interrupts: caller dependent.
362 * This call must not sleep
364 * @poll_get_char: ``int ()(struct uart_port *port)``
366 * Called by kgdb to read a single character directly from the serial
367 * port. If data is available, it should be returned; otherwise the
368 * function should return %NO_POLL_CHAR immediately.
371 * Interrupts: caller dependent.
372 * This call must not sleep
375 unsigned int (*tx_empty)(struct uart_port *);
376 void (*set_mctrl)(struct uart_port *, unsigned int mctrl);
377 unsigned int (*get_mctrl)(struct uart_port *);
378 void (*stop_tx)(struct uart_port *);
379 void (*start_tx)(struct uart_port *);
380 void (*throttle)(struct uart_port *);
381 void (*unthrottle)(struct uart_port *);
382 void (*send_xchar)(struct uart_port *, char ch);
383 void (*stop_rx)(struct uart_port *);
384 void (*start_rx)(struct uart_port *);
385 void (*enable_ms)(struct uart_port *);
386 void (*break_ctl)(struct uart_port *, int ctl);
387 int (*startup)(struct uart_port *);
388 void (*shutdown)(struct uart_port *);
389 void (*flush_buffer)(struct uart_port *);
390 void (*set_termios)(struct uart_port *, struct ktermios *new,
391 const struct ktermios *old);
392 void (*set_ldisc)(struct uart_port *, struct ktermios *);
393 void (*pm)(struct uart_port *, unsigned int state,
394 unsigned int oldstate);
395 const char *(*type)(struct uart_port *);
396 void (*release_port)(struct uart_port *);
397 int (*request_port)(struct uart_port *);
398 void (*config_port)(struct uart_port *, int);
399 int (*verify_port)(struct uart_port *, struct serial_struct *);
400 int (*ioctl)(struct uart_port *, unsigned int, unsigned long);
401 #ifdef CONFIG_CONSOLE_POLL
402 int (*poll_init)(struct uart_port *);
403 void (*poll_put_char)(struct uart_port *, unsigned char);
404 int (*poll_get_char)(struct uart_port *);
408 #define NO_POLL_CHAR 0x00ff0000
409 #define UART_CONFIG_TYPE (1 << 0)
410 #define UART_CONFIG_IRQ (1 << 1)
426 typedef u64 __bitwise upf_t;
427 typedef unsigned int __bitwise upstat_t;
430 spinlock_t lock; /* port lock */
431 unsigned long iobase; /* in/out[bwl] */
432 unsigned char __iomem *membase; /* read/write[bwl] */
433 unsigned int (*serial_in)(struct uart_port *, int);
434 void (*serial_out)(struct uart_port *, int, int);
435 void (*set_termios)(struct uart_port *,
436 struct ktermios *new,
437 const struct ktermios *old);
438 void (*set_ldisc)(struct uart_port *,
440 unsigned int (*get_mctrl)(struct uart_port *);
441 void (*set_mctrl)(struct uart_port *, unsigned int);
442 unsigned int (*get_divisor)(struct uart_port *,
445 void (*set_divisor)(struct uart_port *,
448 unsigned int quot_frac);
449 int (*startup)(struct uart_port *port);
450 void (*shutdown)(struct uart_port *port);
451 void (*throttle)(struct uart_port *port);
452 void (*unthrottle)(struct uart_port *port);
453 int (*handle_irq)(struct uart_port *);
454 void (*pm)(struct uart_port *, unsigned int state,
456 void (*handle_break)(struct uart_port *);
457 int (*rs485_config)(struct uart_port *,
458 struct ktermios *termios,
459 struct serial_rs485 *rs485);
460 int (*iso7816_config)(struct uart_port *,
461 struct serial_iso7816 *iso7816);
462 unsigned int ctrl_id; /* optional serial core controller id */
463 unsigned int port_id; /* optional serial core port id */
464 unsigned int irq; /* irq number */
465 unsigned long irqflags; /* irq flags */
466 unsigned int uartclk; /* base uart clock */
467 unsigned int fifosize; /* tx fifo size */
468 unsigned char x_char; /* xon/xoff char */
469 unsigned char regshift; /* reg offset shift */
470 unsigned char iotype; /* io access style */
471 unsigned char quirks; /* internal quirks */
473 #define UPIO_PORT (SERIAL_IO_PORT) /* 8b I/O port access */
474 #define UPIO_HUB6 (SERIAL_IO_HUB6) /* Hub6 ISA card */
475 #define UPIO_MEM (SERIAL_IO_MEM) /* driver-specific */
476 #define UPIO_MEM32 (SERIAL_IO_MEM32) /* 32b little endian */
477 #define UPIO_AU (SERIAL_IO_AU) /* Au1x00 and RT288x type IO */
478 #define UPIO_TSI (SERIAL_IO_TSI) /* Tsi108/109 type IO */
479 #define UPIO_MEM32BE (SERIAL_IO_MEM32BE) /* 32b big endian */
480 #define UPIO_MEM16 (SERIAL_IO_MEM16) /* 16b little endian */
482 /* quirks must be updated while holding port mutex */
483 #define UPQ_NO_TXEN_TEST BIT(0)
485 unsigned int read_status_mask; /* driver specific */
486 unsigned int ignore_status_mask; /* driver specific */
487 struct uart_state *state; /* pointer to parent state */
488 struct uart_icount icount; /* statistics */
490 struct console *cons; /* struct console, if any */
491 /* flags must be updated while holding port mutex */
495 * These flags must be equivalent to the flags defined in
496 * include/uapi/linux/tty_flags.h which are the userspace definitions
497 * assigned from the serial_struct flags in uart_set_info()
498 * [for bit definitions in the UPF_CHANGE_MASK]
500 * Bits [0..ASYNCB_LAST_USER] are userspace defined/visible/changeable
501 * The remaining bits are serial-core specific and not modifiable by
504 #define UPF_FOURPORT ((__force upf_t) ASYNC_FOURPORT /* 1 */ )
505 #define UPF_SAK ((__force upf_t) ASYNC_SAK /* 2 */ )
506 #define UPF_SPD_HI ((__force upf_t) ASYNC_SPD_HI /* 4 */ )
507 #define UPF_SPD_VHI ((__force upf_t) ASYNC_SPD_VHI /* 5 */ )
508 #define UPF_SPD_CUST ((__force upf_t) ASYNC_SPD_CUST /* 0x0030 */ )
509 #define UPF_SPD_WARP ((__force upf_t) ASYNC_SPD_WARP /* 0x1010 */ )
510 #define UPF_SPD_MASK ((__force upf_t) ASYNC_SPD_MASK /* 0x1030 */ )
511 #define UPF_SKIP_TEST ((__force upf_t) ASYNC_SKIP_TEST /* 6 */ )
512 #define UPF_AUTO_IRQ ((__force upf_t) ASYNC_AUTO_IRQ /* 7 */ )
513 #define UPF_HARDPPS_CD ((__force upf_t) ASYNC_HARDPPS_CD /* 11 */ )
514 #define UPF_SPD_SHI ((__force upf_t) ASYNC_SPD_SHI /* 12 */ )
515 #define UPF_LOW_LATENCY ((__force upf_t) ASYNC_LOW_LATENCY /* 13 */ )
516 #define UPF_BUGGY_UART ((__force upf_t) ASYNC_BUGGY_UART /* 14 */ )
517 #define UPF_MAGIC_MULTIPLIER ((__force upf_t) ASYNC_MAGIC_MULTIPLIER /* 16 */ )
519 #define UPF_NO_THRE_TEST ((__force upf_t) BIT_ULL(19))
520 /* Port has hardware-assisted h/w flow control */
521 #define UPF_AUTO_CTS ((__force upf_t) BIT_ULL(20))
522 #define UPF_AUTO_RTS ((__force upf_t) BIT_ULL(21))
523 #define UPF_HARD_FLOW ((__force upf_t) (UPF_AUTO_CTS | UPF_AUTO_RTS))
524 /* Port has hardware-assisted s/w flow control */
525 #define UPF_SOFT_FLOW ((__force upf_t) BIT_ULL(22))
526 #define UPF_CONS_FLOW ((__force upf_t) BIT_ULL(23))
527 #define UPF_SHARE_IRQ ((__force upf_t) BIT_ULL(24))
528 #define UPF_EXAR_EFR ((__force upf_t) BIT_ULL(25))
529 #define UPF_BUG_THRE ((__force upf_t) BIT_ULL(26))
530 /* The exact UART type is known and should not be probed. */
531 #define UPF_FIXED_TYPE ((__force upf_t) BIT_ULL(27))
532 #define UPF_BOOT_AUTOCONF ((__force upf_t) BIT_ULL(28))
533 #define UPF_FIXED_PORT ((__force upf_t) BIT_ULL(29))
534 #define UPF_DEAD ((__force upf_t) BIT_ULL(30))
535 #define UPF_IOREMAP ((__force upf_t) BIT_ULL(31))
536 #define UPF_FULL_PROBE ((__force upf_t) BIT_ULL(32))
538 #define __UPF_CHANGE_MASK 0x17fff
539 #define UPF_CHANGE_MASK ((__force upf_t) __UPF_CHANGE_MASK)
540 #define UPF_USR_MASK ((__force upf_t) (UPF_SPD_MASK|UPF_LOW_LATENCY))
542 #if __UPF_CHANGE_MASK > ASYNC_FLAGS
543 #error Change mask not equivalent to userspace-visible bit defines
547 * Must hold termios_rwsem, port mutex and port lock to change;
548 * can hold any one lock to read.
552 #define UPSTAT_CTS_ENABLE ((__force upstat_t) (1 << 0))
553 #define UPSTAT_DCD_ENABLE ((__force upstat_t) (1 << 1))
554 #define UPSTAT_AUTORTS ((__force upstat_t) (1 << 2))
555 #define UPSTAT_AUTOCTS ((__force upstat_t) (1 << 3))
556 #define UPSTAT_AUTOXOFF ((__force upstat_t) (1 << 4))
557 #define UPSTAT_SYNC_FIFO ((__force upstat_t) (1 << 5))
559 bool hw_stopped; /* sw-assisted CTS flow state */
560 unsigned int mctrl; /* current modem ctrl settings */
561 unsigned int frame_time; /* frame timing in ns */
562 unsigned int type; /* port type */
563 const struct uart_ops *ops;
564 unsigned int custom_divisor;
565 unsigned int line; /* port index */
567 resource_size_t mapbase; /* for ioremap */
568 resource_size_t mapsize;
569 struct device *dev; /* serial port physical parent device */
570 struct serial_port_device *port_dev; /* serial core port device */
572 unsigned long sysrq; /* sysrq timeout */
573 u8 sysrq_ch; /* char for sysrq */
574 unsigned char has_sysrq;
575 unsigned char sysrq_seq; /* index in sysrq_toggle_seq */
577 unsigned char hub6; /* this should be in the 8250 driver */
578 unsigned char suspended;
579 unsigned char console_reinit;
580 const char *name; /* port name */
581 struct attribute_group *attr_group; /* port specific attributes */
582 const struct attribute_group **tty_groups; /* all attributes (serial core use only) */
583 struct serial_rs485 rs485;
584 struct serial_rs485 rs485_supported; /* Supported mask for serial_rs485 */
585 struct gpio_desc *rs485_term_gpio; /* enable RS485 bus termination */
586 struct gpio_desc *rs485_rx_during_tx_gpio; /* Output GPIO that sets the state of RS485 RX during TX */
587 struct serial_iso7816 iso7816;
588 void *private_data; /* generic platform data pointer */
591 static inline int serial_port_in(struct uart_port *up, int offset)
593 return up->serial_in(up, offset);
596 static inline void serial_port_out(struct uart_port *up, int offset, int value)
598 up->serial_out(up, offset, value);
602 * enum uart_pm_state - power states for UARTs
603 * @UART_PM_STATE_ON: UART is powered, up and operational
604 * @UART_PM_STATE_OFF: UART is powered off
605 * @UART_PM_STATE_UNDEFINED: sentinel
608 UART_PM_STATE_ON = 0,
609 UART_PM_STATE_OFF = 3, /* number taken from ACPI */
610 UART_PM_STATE_UNDEFINED,
614 * This is the state information which is persistent across opens.
617 struct tty_port port;
619 enum uart_pm_state pm_state;
620 struct circ_buf xmit;
623 wait_queue_head_t remove_wait;
624 struct uart_port *uart_port;
627 #define UART_XMIT_SIZE PAGE_SIZE
630 /* number of characters left in xmit buffer before we ask for more */
631 #define WAKEUP_CHARS 256
634 * uart_xmit_advance - Advance xmit buffer and account Tx'ed chars
635 * @up: uart_port structure describing the port
636 * @chars: number of characters sent
638 * This function advances the tail of circular xmit buffer by the number of
639 * @chars transmitted and handles accounting of transmitted bytes (into
642 static inline void uart_xmit_advance(struct uart_port *up, unsigned int chars)
644 struct circ_buf *xmit = &up->state->xmit;
646 xmit->tail = (xmit->tail + chars) & (UART_XMIT_SIZE - 1);
647 up->icount.tx += chars;
654 struct module *owner;
655 const char *driver_name;
656 const char *dev_name;
660 struct console *cons;
663 * these are private; the low level driver should not
664 * touch these; they should be initialised to NULL
666 struct uart_state *state;
667 struct tty_driver *tty_driver;
670 void uart_write_wakeup(struct uart_port *port);
672 #define __uart_port_tx(uport, ch, tx_ready, put_char, tx_done, for_test, \
675 struct uart_port *__port = (uport); \
676 struct circ_buf *xmit = &__port->state->xmit; \
677 unsigned int pending; \
679 for (; (for_test) && (tx_ready); (for_post), __port->icount.tx++) { \
680 if (__port->x_char) { \
681 (ch) = __port->x_char; \
683 __port->x_char = 0; \
687 if (uart_circ_empty(xmit) || uart_tx_stopped(__port)) \
690 (ch) = xmit->buf[xmit->tail]; \
692 xmit->tail = (xmit->tail + 1) % UART_XMIT_SIZE; \
697 pending = uart_circ_chars_pending(xmit); \
698 if (pending < WAKEUP_CHARS) { \
699 uart_write_wakeup(__port); \
702 __port->ops->stop_tx(__port); \
709 * uart_port_tx_limited -- transmit helper for uart_port with count limiting
711 * @ch: variable to store a character to be written to the HW
712 * @count: a limit of characters to send
713 * @tx_ready: can HW accept more data function
714 * @put_char: function to write a character
715 * @tx_done: function to call after the loop is done
717 * This helper transmits characters from the xmit buffer to the hardware using
718 * @put_char(). It does so until @count characters are sent and while @tx_ready
721 * Returns: the number of characters in the xmit buffer when done.
723 * The expression in macro parameters shall be designed as follows:
724 * * **tx_ready:** should evaluate to true if the HW can accept more data to
725 * be sent. This parameter can be %true, which means the HW is always ready.
726 * * **put_char:** shall write @ch to the device of @port.
727 * * **tx_done:** when the write loop is done, this can perform arbitrary
728 * action before potential invocation of ops->stop_tx() happens. If the
729 * driver does not need to do anything, use e.g. ({}).
731 * For all of them, @port->lock is held, interrupts are locally disabled and
732 * the expressions must not sleep.
734 #define uart_port_tx_limited(port, ch, count, tx_ready, put_char, tx_done) ({ \
735 unsigned int __count = (count); \
736 __uart_port_tx(port, ch, tx_ready, put_char, tx_done, __count, \
741 * uart_port_tx -- transmit helper for uart_port
743 * @ch: variable to store a character to be written to the HW
744 * @tx_ready: can HW accept more data function
745 * @put_char: function to write a character
747 * See uart_port_tx_limited() for more details.
749 #define uart_port_tx(port, ch, tx_ready, put_char) \
750 __uart_port_tx(port, ch, tx_ready, put_char, ({}), true, ({}))
755 void uart_update_timeout(struct uart_port *port, unsigned int cflag,
757 unsigned int uart_get_baud_rate(struct uart_port *port, struct ktermios *termios,
758 const struct ktermios *old, unsigned int min,
760 unsigned int uart_get_divisor(struct uart_port *port, unsigned int baud);
763 * Calculates FIFO drain time.
765 static inline unsigned long uart_fifo_timeout(struct uart_port *port)
767 u64 fifo_timeout = (u64)READ_ONCE(port->frame_time) * port->fifosize;
769 /* Add .02 seconds of slop */
770 fifo_timeout += 20 * NSEC_PER_MSEC;
772 return max(nsecs_to_jiffies(fifo_timeout), 1UL);
775 /* Base timer interval for polling */
776 static inline int uart_poll_timeout(struct uart_port *port)
778 int timeout = uart_fifo_timeout(port);
780 return timeout > 6 ? (timeout / 2 - 2) : 1;
786 struct earlycon_device {
788 struct uart_port port;
789 char options[32]; /* e.g., 115200n8 */
795 char name_term; /* In case compiler didn't '\0' term name */
796 char compatible[128];
797 int (*setup)(struct earlycon_device *, const char *options);
800 extern const struct earlycon_id __earlycon_table[];
801 extern const struct earlycon_id __earlycon_table_end[];
803 #if defined(CONFIG_SERIAL_EARLYCON) && !defined(MODULE)
804 #define EARLYCON_USED_OR_UNUSED __used
806 #define EARLYCON_USED_OR_UNUSED __maybe_unused
809 #define OF_EARLYCON_DECLARE(_name, compat, fn) \
810 static const struct earlycon_id __UNIQUE_ID(__earlycon_##_name) \
811 EARLYCON_USED_OR_UNUSED __section("__earlycon_table") \
812 __aligned(__alignof__(struct earlycon_id)) \
813 = { .name = __stringify(_name), \
814 .compatible = compat, \
817 #define EARLYCON_DECLARE(_name, fn) OF_EARLYCON_DECLARE(_name, "", fn)
819 int of_setup_earlycon(const struct earlycon_id *match, unsigned long node,
820 const char *options);
822 #ifdef CONFIG_SERIAL_EARLYCON
823 extern bool earlycon_acpi_spcr_enable __initdata;
824 int setup_earlycon(char *buf);
826 static const bool earlycon_acpi_spcr_enable EARLYCON_USED_OR_UNUSED;
827 static inline int setup_earlycon(char *buf) { return 0; }
830 /* Variant of uart_console_registered() when the console_list_lock is held. */
831 static inline bool uart_console_registered_locked(struct uart_port *port)
833 return uart_console(port) && console_is_registered_locked(port->cons);
836 static inline bool uart_console_registered(struct uart_port *port)
838 return uart_console(port) && console_is_registered(port->cons);
841 struct uart_port *uart_get_console(struct uart_port *ports, int nr,
843 int uart_parse_earlycon(char *p, unsigned char *iotype, resource_size_t *addr,
845 void uart_parse_options(const char *options, int *baud, int *parity, int *bits,
847 int uart_set_options(struct uart_port *port, struct console *co, int baud,
848 int parity, int bits, int flow);
849 struct tty_driver *uart_console_device(struct console *co, int *index);
850 void uart_console_write(struct uart_port *port, const char *s,
852 void (*putchar)(struct uart_port *, unsigned char));
855 * Port/driver registration/removal
857 int uart_register_driver(struct uart_driver *uart);
858 void uart_unregister_driver(struct uart_driver *uart);
859 int uart_add_one_port(struct uart_driver *reg, struct uart_port *port);
860 void uart_remove_one_port(struct uart_driver *reg, struct uart_port *port);
861 bool uart_match_port(const struct uart_port *port1,
862 const struct uart_port *port2);
867 int uart_suspend_port(struct uart_driver *reg, struct uart_port *port);
868 int uart_resume_port(struct uart_driver *reg, struct uart_port *port);
870 #define uart_circ_empty(circ) ((circ)->head == (circ)->tail)
871 #define uart_circ_clear(circ) ((circ)->head = (circ)->tail = 0)
873 #define uart_circ_chars_pending(circ) \
874 (CIRC_CNT((circ)->head, (circ)->tail, UART_XMIT_SIZE))
876 #define uart_circ_chars_free(circ) \
877 (CIRC_SPACE((circ)->head, (circ)->tail, UART_XMIT_SIZE))
879 static inline int uart_tx_stopped(struct uart_port *port)
881 struct tty_struct *tty = port->state->port.tty;
882 if ((tty && tty->flow.stopped) || port->hw_stopped)
887 static inline bool uart_cts_enabled(struct uart_port *uport)
889 return !!(uport->status & UPSTAT_CTS_ENABLE);
892 static inline bool uart_softcts_mode(struct uart_port *uport)
894 upstat_t mask = UPSTAT_CTS_ENABLE | UPSTAT_AUTOCTS;
896 return ((uport->status & mask) == UPSTAT_CTS_ENABLE);
900 * The following are helper functions for the low level drivers.
903 void uart_handle_dcd_change(struct uart_port *uport, bool active);
904 void uart_handle_cts_change(struct uart_port *uport, bool active);
906 void uart_insert_char(struct uart_port *port, unsigned int status,
907 unsigned int overrun, u8 ch, u8 flag);
909 void uart_xchar_out(struct uart_port *uport, int offset);
911 #ifdef CONFIG_MAGIC_SYSRQ_SERIAL
912 #define SYSRQ_TIMEOUT (HZ * 5)
914 bool uart_try_toggle_sysrq(struct uart_port *port, u8 ch);
916 static inline int uart_handle_sysrq_char(struct uart_port *port, u8 ch)
921 if (ch && time_before(jiffies, port->sysrq)) {
927 if (uart_try_toggle_sysrq(port, ch))
935 static inline int uart_prepare_sysrq_char(struct uart_port *port, u8 ch)
940 if (ch && time_before(jiffies, port->sysrq)) {
946 if (uart_try_toggle_sysrq(port, ch))
954 static inline void uart_unlock_and_check_sysrq(struct uart_port *port)
958 if (!port->has_sysrq) {
959 spin_unlock(&port->lock);
963 sysrq_ch = port->sysrq_ch;
966 spin_unlock(&port->lock);
969 handle_sysrq(sysrq_ch);
972 static inline void uart_unlock_and_check_sysrq_irqrestore(struct uart_port *port,
977 if (!port->has_sysrq) {
978 spin_unlock_irqrestore(&port->lock, flags);
982 sysrq_ch = port->sysrq_ch;
985 spin_unlock_irqrestore(&port->lock, flags);
988 handle_sysrq(sysrq_ch);
990 #else /* CONFIG_MAGIC_SYSRQ_SERIAL */
991 static inline int uart_handle_sysrq_char(struct uart_port *port, u8 ch)
995 static inline int uart_prepare_sysrq_char(struct uart_port *port, u8 ch)
999 static inline void uart_unlock_and_check_sysrq(struct uart_port *port)
1001 spin_unlock(&port->lock);
1003 static inline void uart_unlock_and_check_sysrq_irqrestore(struct uart_port *port,
1004 unsigned long flags)
1006 spin_unlock_irqrestore(&port->lock, flags);
1008 #endif /* CONFIG_MAGIC_SYSRQ_SERIAL */
1011 * We do the SysRQ and SAK checking like this...
1013 static inline int uart_handle_break(struct uart_port *port)
1015 struct uart_state *state = port->state;
1017 if (port->handle_break)
1018 port->handle_break(port);
1020 #ifdef CONFIG_MAGIC_SYSRQ_SERIAL
1021 if (port->has_sysrq && uart_console(port)) {
1023 port->sysrq = jiffies + SYSRQ_TIMEOUT;
1029 if (port->flags & UPF_SAK)
1030 do_SAK(state->port.tty);
1035 * UART_ENABLE_MS - determine if port should enable modem status irqs
1037 #define UART_ENABLE_MS(port,cflag) ((port)->flags & UPF_HARDPPS_CD || \
1038 (cflag) & CRTSCTS || \
1039 !((cflag) & CLOCAL))
1041 int uart_get_rs485_mode(struct uart_port *port);
1042 #endif /* LINUX_SERIAL_CORE_H */