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/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>
21
22#ifdef CONFIG_SERIAL_CORE_CONSOLE
23#define uart_console(port) \
24 ((port)->cons && (port)->cons->index == (port)->line)
25#else
26#define uart_console(port) ({ (void)port; 0; })
27#endif
28
29struct uart_port;
30struct serial_struct;
31struct serial_port_device;
32struct device;
33struct gpio_desc;
34
35/**
36 * struct uart_ops -- interface between serial_core and the driver
37 *
38 * This structure describes all the operations that can be done on the
39 * physical hardware.
40 *
41 * @tx_empty: ``unsigned int ()(struct uart_port *port)``
42 *
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.
47 *
48 * Locking: none.
49 * Interrupts: caller dependent.
50 * This call must not sleep
51 *
52 * @set_mctrl: ``void ()(struct uart_port *port, unsigned int mctrl)``
53 *
54 * This function sets the modem control lines for @port to the state
55 * described by @mctrl. The relevant bits of @mctrl are:
56 *
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.
62 *
63 * If the appropriate bit is set, the signal should be driven
64 * active. If the bit is clear, the signal should be driven
65 * inactive.
66 *
67 * Locking: @port->lock taken.
68 * Interrupts: locally disabled.
69 * This call must not sleep
70 *
71 * @get_mctrl: ``unsigned int ()(struct uart_port *port)``
72 *
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:
76 *
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
81 *
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.
86 *
87 * Locking: @port->lock taken.
88 * Interrupts: locally disabled.
89 * This call must not sleep
90 *
91 * @stop_tx: ``void ()(struct uart_port *port)``
92 *
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.
96 *
97 * The driver should stop transmitting characters as soon as possible.
98 *
99 * Locking: @port->lock taken.
100 * Interrupts: locally disabled.
101 * This call must not sleep
102 *
103 * @start_tx: ``void ()(struct uart_port *port)``
104 *
105 * Start transmitting characters.
106 *
107 * Locking: @port->lock taken.
108 * Interrupts: locally disabled.
109 * This call must not sleep
110 *
111 * @throttle: ``void ()(struct uart_port *port)``
112 *
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.
117 *
118 * Locking: serialized with @unthrottle() and termios modification by the
119 * tty layer.
120 *
121 * @unthrottle: ``void ()(struct uart_port *port)``
122 *
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
125 * disciplines.
126 *
127 * This will be called only if hardware assisted flow control is enabled.
128 *
129 * Locking: serialized with @throttle() and termios modification by the
130 * tty layer.
131 *
132 * @send_xchar: ``void ()(struct uart_port *port, char ch)``
133 *
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.
139 *
140 * Do not transmit if @ch == '\0' (%__DISABLED_CHAR).
141 *
142 * Locking: none.
143 * Interrupts: caller dependent.
144 *
145 * @start_rx: ``void ()(struct uart_port *port)``
146 *
147 * Start receiving characters.
148 *
149 * Locking: @port->lock taken.
150 * Interrupts: locally disabled.
151 * This call must not sleep
152 *
153 * @stop_rx: ``void ()(struct uart_port *port)``
154 *
155 * Stop receiving characters; the @port is in the process of being closed.
156 *
157 * Locking: @port->lock taken.
158 * Interrupts: locally disabled.
159 * This call must not sleep
160 *
161 * @enable_ms: ``void ()(struct uart_port *port)``
162 *
163 * Enable the modem status interrupts.
164 *
165 * This method may be called multiple times. Modem status interrupts
166 * should be disabled when the @shutdown() method is called.
167 *
168 * Locking: @port->lock taken.
169 * Interrupts: locally disabled.
170 * This call must not sleep
171 *
172 * @break_ctl: ``void ()(struct uart_port *port, int ctl)``
173 *
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.
177 *
178 * Locking: caller holds tty_port->mutex
179 *
180 * @startup: ``int ()(struct uart_port *port)``
181 *
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().
185 *
186 * This method will only be called when the port is initially opened.
187 *
188 * Locking: port_sem taken.
189 * Interrupts: globally disabled.
190 *
191 * @shutdown: ``void ()(struct uart_port *port)``
192 *
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().
196 *
197 * Drivers must not access @port->state once this call has completed.
198 *
199 * This method will only be called when there are no more users of this
200 * @port.
201 *
202 * Locking: port_sem taken.
203 * Interrupts: caller dependent.
204 *
205 * @flush_buffer: ``void ()(struct uart_port *port)``
206 *
207 * Flush any write buffers, reset any DMA state and stop any ongoing DMA
208 * transfers.
209 *
210 * This will be called whenever the @port->state->xmit circular buffer is
211 * cleared.
212 *
213 * Locking: @port->lock taken.
214 * Interrupts: locally disabled.
215 * This call must not sleep
216 *
217 * @set_termios: ``void ()(struct uart_port *port, struct ktermios *new,
218 * struct ktermios *old)``
219 *
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:
224 *
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.
234 *
235 * Relevant ktermios::c_iflag bits are:
236 *
237 * - %INPCK - enable frame and parity error events to be passed to the TTY
238 * layer.
239 * - %BRKINT / %PARMRK - both of these enable break events to be passed to
240 * the TTY layer.
241 * - %IGNPAR - ignore parity and framing errors.
242 * - %IGNBRK - ignore break errors. If %IGNPAR is also set, ignore overrun
243 * errors as well.
244 *
245 * The interaction of the ktermios::c_iflag bits is as follows (parity
246 * error given as an example):
247 *
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 * ============ ======= ======= =========================================
256 *
257 * Other flags may be used (eg, xon/xoff characters) if your hardware
258 * supports hardware "soft" flow control.
259 *
260 * Locking: caller holds tty_port->mutex
261 * Interrupts: caller dependent.
262 * This call must not sleep
263 *
264 * @set_ldisc: ``void ()(struct uart_port *port, struct ktermios *termios)``
265 *
266 * Notifier for discipline change. See
267 * Documentation/driver-api/tty/tty_ldisc.rst.
268 *
269 * Locking: caller holds tty_port->mutex
270 *
271 * @pm: ``void ()(struct uart_port *port, unsigned int state,
272 * unsigned int oldstate)``
273 *
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.
277 *
278 * This function should not be used to grab any resources.
279 *
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.
283 *
284 * Locking: none.
285 * Interrupts: caller dependent.
286 *
287 * @type: ``const char *()(struct uart_port *port)``
288 *
289 * Return a pointer to a string constant describing the specified @port,
290 * or return %NULL, in which case the string 'unknown' is substituted.
291 *
292 * Locking: none.
293 * Interrupts: caller dependent.
294 *
295 * @release_port: ``void ()(struct uart_port *port)``
296 *
297 * Release any memory and IO region resources currently in use by the
298 * @port.
299 *
300 * Locking: none.
301 * Interrupts: caller dependent.
302 *
303 * @request_port: ``int ()(struct uart_port *port)``
304 *
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.
308 *
309 * Locking: none.
310 * Interrupts: caller dependent.
311 *
312 * @config_port: ``void ()(struct uart_port *port, int type)``
313 *
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
318 * port was detected.
319 *
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).
324 *
325 * Locking: none.
326 * Interrupts: caller dependent.
327 *
328 * @verify_port: ``int ()(struct uart_port *port,
329 * struct serial_struct *serinfo)``
330 *
331 * Verify the new serial port information contained within @serinfo is
332 * suitable for this port type.
333 *
334 * Locking: none.
335 * Interrupts: caller dependent.
336 *
337 * @ioctl: ``int ()(struct uart_port *port, unsigned int cmd,
338 * unsigned long arg)``
339 *
340 * Perform any port specific IOCTLs. IOCTL commands must be defined using
341 * the standard numbering system found in <asm/ioctl.h>.
342 *
343 * Locking: none.
344 * Interrupts: caller dependent.
345 *
346 * @poll_init: ``int ()(struct uart_port *port)``
347 *
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.
351 *
352 * Locking: %tty_mutex and tty_port->mutex taken.
353 * Interrupts: n/a.
354 *
355 * @poll_put_char: ``void ()(struct uart_port *port, unsigned char ch)``
356 *
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.
359 *
360 * Locking: none.
361 * Interrupts: caller dependent.
362 * This call must not sleep
363 *
364 * @poll_get_char: ``int ()(struct uart_port *port)``
365 *
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.
369 *
370 * Locking: none.
371 * Interrupts: caller dependent.
372 * This call must not sleep
373 */
374struct uart_ops {
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 *);
405#endif
406};
407
408#define NO_POLL_CHAR 0x00ff0000
409#define UART_CONFIG_TYPE (1 << 0)
410#define UART_CONFIG_IRQ (1 << 1)
411
412struct uart_icount {
413 __u32 cts;
414 __u32 dsr;
415 __u32 rng;
416 __u32 dcd;
417 __u32 rx;
418 __u32 tx;
419 __u32 frame;
420 __u32 overrun;
421 __u32 parity;
422 __u32 brk;
423 __u32 buf_overrun;
424};
425
426typedef u64 __bitwise upf_t;
427typedef unsigned int __bitwise upstat_t;
428
429struct uart_port {
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 *,
439 struct ktermios *);
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 *,
443 unsigned int baud,
444 unsigned int *frac);
445 void (*set_divisor)(struct uart_port *,
446 unsigned int baud,
447 unsigned int quot,
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,
455 unsigned int old);
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 */
472
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 */
481
482 /* quirks must be updated while holding port mutex */
483#define UPQ_NO_TXEN_TEST BIT(0)
484
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 */
489
490 struct console *cons; /* struct console, if any */
491 /* flags must be updated while holding port mutex */
492 upf_t flags;
493
494 /*
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]
499 *
500 * Bits [0..ASYNCB_LAST_USER] are userspace defined/visible/changeable
501 * The remaining bits are serial-core specific and not modifiable by
502 * userspace.
503 */
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 */ )
518
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))
537
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))
541
542#if __UPF_CHANGE_MASK > ASYNC_FLAGS
543#error Change mask not equivalent to userspace-visible bit defines
544#endif
545
546 /*
547 * Must hold termios_rwsem, port mutex and port lock to change;
548 * can hold any one lock to read.
549 */
550 upstat_t status;
551
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))
558
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 */
566 unsigned int minor;
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 */
571
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 */
576
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 */
589};
590
591/**
592 * uart_port_lock - Lock the UART port
593 * @up: Pointer to UART port structure
594 */
595static inline void uart_port_lock(struct uart_port *up)
596{
597 spin_lock(lock: &up->lock);
598}
599
600/**
601 * uart_port_lock_irq - Lock the UART port and disable interrupts
602 * @up: Pointer to UART port structure
603 */
604static inline void uart_port_lock_irq(struct uart_port *up)
605{
606 spin_lock_irq(lock: &up->lock);
607}
608
609/**
610 * uart_port_lock_irqsave - Lock the UART port, save and disable interrupts
611 * @up: Pointer to UART port structure
612 * @flags: Pointer to interrupt flags storage
613 */
614static inline void uart_port_lock_irqsave(struct uart_port *up, unsigned long *flags)
615{
616 spin_lock_irqsave(&up->lock, *flags);
617}
618
619/**
620 * uart_port_trylock - Try to lock the UART port
621 * @up: Pointer to UART port structure
622 *
623 * Returns: True if lock was acquired, false otherwise
624 */
625static inline bool uart_port_trylock(struct uart_port *up)
626{
627 return spin_trylock(lock: &up->lock);
628}
629
630/**
631 * uart_port_trylock_irqsave - Try to lock the UART port, save and disable interrupts
632 * @up: Pointer to UART port structure
633 * @flags: Pointer to interrupt flags storage
634 *
635 * Returns: True if lock was acquired, false otherwise
636 */
637static inline bool uart_port_trylock_irqsave(struct uart_port *up, unsigned long *flags)
638{
639 return spin_trylock_irqsave(&up->lock, *flags);
640}
641
642/**
643 * uart_port_unlock - Unlock the UART port
644 * @up: Pointer to UART port structure
645 */
646static inline void uart_port_unlock(struct uart_port *up)
647{
648 spin_unlock(lock: &up->lock);
649}
650
651/**
652 * uart_port_unlock_irq - Unlock the UART port and re-enable interrupts
653 * @up: Pointer to UART port structure
654 */
655static inline void uart_port_unlock_irq(struct uart_port *up)
656{
657 spin_unlock_irq(lock: &up->lock);
658}
659
660/**
661 * uart_port_unlock_irqrestore - Unlock the UART port, restore interrupts
662 * @up: Pointer to UART port structure
663 * @flags: The saved interrupt flags for restore
664 */
665static inline void uart_port_unlock_irqrestore(struct uart_port *up, unsigned long flags)
666{
667 spin_unlock_irqrestore(lock: &up->lock, flags);
668}
669
670static inline int serial_port_in(struct uart_port *up, int offset)
671{
672 return up->serial_in(up, offset);
673}
674
675static inline void serial_port_out(struct uart_port *up, int offset, int value)
676{
677 up->serial_out(up, offset, value);
678}
679
680/**
681 * enum uart_pm_state - power states for UARTs
682 * @UART_PM_STATE_ON: UART is powered, up and operational
683 * @UART_PM_STATE_OFF: UART is powered off
684 * @UART_PM_STATE_UNDEFINED: sentinel
685 */
686enum uart_pm_state {
687 UART_PM_STATE_ON = 0,
688 UART_PM_STATE_OFF = 3, /* number taken from ACPI */
689 UART_PM_STATE_UNDEFINED,
690};
691
692/*
693 * This is the state information which is persistent across opens.
694 */
695struct uart_state {
696 struct tty_port port;
697
698 enum uart_pm_state pm_state;
699 struct circ_buf xmit;
700
701 atomic_t refcount;
702 wait_queue_head_t remove_wait;
703 struct uart_port *uart_port;
704};
705
706#define UART_XMIT_SIZE PAGE_SIZE
707
708
709/* number of characters left in xmit buffer before we ask for more */
710#define WAKEUP_CHARS 256
711
712/**
713 * uart_xmit_advance - Advance xmit buffer and account Tx'ed chars
714 * @up: uart_port structure describing the port
715 * @chars: number of characters sent
716 *
717 * This function advances the tail of circular xmit buffer by the number of
718 * @chars transmitted and handles accounting of transmitted bytes (into
719 * @up's icount.tx).
720 */
721static inline void uart_xmit_advance(struct uart_port *up, unsigned int chars)
722{
723 struct circ_buf *xmit = &up->state->xmit;
724
725 xmit->tail = (xmit->tail + chars) & (UART_XMIT_SIZE - 1);
726 up->icount.tx += chars;
727}
728
729struct module;
730struct tty_driver;
731
732struct uart_driver {
733 struct module *owner;
734 const char *driver_name;
735 const char *dev_name;
736 int major;
737 int minor;
738 int nr;
739 struct console *cons;
740
741 /*
742 * these are private; the low level driver should not
743 * touch these; they should be initialised to NULL
744 */
745 struct uart_state *state;
746 struct tty_driver *tty_driver;
747};
748
749void uart_write_wakeup(struct uart_port *port);
750
751#define __uart_port_tx(uport, ch, tx_ready, put_char, tx_done, for_test, \
752 for_post) \
753({ \
754 struct uart_port *__port = (uport); \
755 struct circ_buf *xmit = &__port->state->xmit; \
756 unsigned int pending; \
757 \
758 for (; (for_test) && (tx_ready); (for_post), __port->icount.tx++) { \
759 if (__port->x_char) { \
760 (ch) = __port->x_char; \
761 (put_char); \
762 __port->x_char = 0; \
763 continue; \
764 } \
765 \
766 if (uart_circ_empty(xmit) || uart_tx_stopped(__port)) \
767 break; \
768 \
769 (ch) = xmit->buf[xmit->tail]; \
770 (put_char); \
771 xmit->tail = (xmit->tail + 1) % UART_XMIT_SIZE; \
772 } \
773 \
774 (tx_done); \
775 \
776 pending = uart_circ_chars_pending(xmit); \
777 if (pending < WAKEUP_CHARS) { \
778 uart_write_wakeup(__port); \
779 \
780 if (pending == 0) \
781 __port->ops->stop_tx(__port); \
782 } \
783 \
784 pending; \
785})
786
787/**
788 * uart_port_tx_limited -- transmit helper for uart_port with count limiting
789 * @port: uart port
790 * @ch: variable to store a character to be written to the HW
791 * @count: a limit of characters to send
792 * @tx_ready: can HW accept more data function
793 * @put_char: function to write a character
794 * @tx_done: function to call after the loop is done
795 *
796 * This helper transmits characters from the xmit buffer to the hardware using
797 * @put_char(). It does so until @count characters are sent and while @tx_ready
798 * evaluates to true.
799 *
800 * Returns: the number of characters in the xmit buffer when done.
801 *
802 * The expression in macro parameters shall be designed as follows:
803 * * **tx_ready:** should evaluate to true if the HW can accept more data to
804 * be sent. This parameter can be %true, which means the HW is always ready.
805 * * **put_char:** shall write @ch to the device of @port.
806 * * **tx_done:** when the write loop is done, this can perform arbitrary
807 * action before potential invocation of ops->stop_tx() happens. If the
808 * driver does not need to do anything, use e.g. ({}).
809 *
810 * For all of them, @port->lock is held, interrupts are locally disabled and
811 * the expressions must not sleep.
812 */
813#define uart_port_tx_limited(port, ch, count, tx_ready, put_char, tx_done) ({ \
814 unsigned int __count = (count); \
815 __uart_port_tx(port, ch, tx_ready, put_char, tx_done, __count, \
816 __count--); \
817})
818
819/**
820 * uart_port_tx -- transmit helper for uart_port
821 * @port: uart port
822 * @ch: variable to store a character to be written to the HW
823 * @tx_ready: can HW accept more data function
824 * @put_char: function to write a character
825 *
826 * See uart_port_tx_limited() for more details.
827 */
828#define uart_port_tx(port, ch, tx_ready, put_char) \
829 __uart_port_tx(port, ch, tx_ready, put_char, ({}), true, ({}))
830
831/*
832 * Baud rate helpers.
833 */
834void uart_update_timeout(struct uart_port *port, unsigned int cflag,
835 unsigned int baud);
836unsigned int uart_get_baud_rate(struct uart_port *port, struct ktermios *termios,
837 const struct ktermios *old, unsigned int min,
838 unsigned int max);
839unsigned int uart_get_divisor(struct uart_port *port, unsigned int baud);
840
841/*
842 * Calculates FIFO drain time.
843 */
844static inline unsigned long uart_fifo_timeout(struct uart_port *port)
845{
846 u64 fifo_timeout = (u64)READ_ONCE(port->frame_time) * port->fifosize;
847
848 /* Add .02 seconds of slop */
849 fifo_timeout += 20 * NSEC_PER_MSEC;
850
851 return max(nsecs_to_jiffies(fifo_timeout), 1UL);
852}
853
854/* Base timer interval for polling */
855static inline int uart_poll_timeout(struct uart_port *port)
856{
857 int timeout = uart_fifo_timeout(port);
858
859 return timeout > 6 ? (timeout / 2 - 2) : 1;
860}
861
862/*
863 * Console helpers.
864 */
865struct earlycon_device {
866 struct console *con;
867 struct uart_port port;
868 char options[32]; /* e.g., 115200n8 */
869 unsigned int baud;
870};
871
872struct earlycon_id {
873 char name[15];
874 char name_term; /* In case compiler didn't '\0' term name */
875 char compatible[128];
876 int (*setup)(struct earlycon_device *, const char *options);
877};
878
879extern const struct earlycon_id __earlycon_table[];
880extern const struct earlycon_id __earlycon_table_end[];
881
882#if defined(CONFIG_SERIAL_EARLYCON) && !defined(MODULE)
883#define EARLYCON_USED_OR_UNUSED __used
884#else
885#define EARLYCON_USED_OR_UNUSED __maybe_unused
886#endif
887
888#define OF_EARLYCON_DECLARE(_name, compat, fn) \
889 static const struct earlycon_id __UNIQUE_ID(__earlycon_##_name) \
890 EARLYCON_USED_OR_UNUSED __section("__earlycon_table") \
891 __aligned(__alignof__(struct earlycon_id)) \
892 = { .name = __stringify(_name), \
893 .compatible = compat, \
894 .setup = fn }
895
896#define EARLYCON_DECLARE(_name, fn) OF_EARLYCON_DECLARE(_name, "", fn)
897
898int of_setup_earlycon(const struct earlycon_id *match, unsigned long node,
899 const char *options);
900
901#ifdef CONFIG_SERIAL_EARLYCON
902extern bool earlycon_acpi_spcr_enable __initdata;
903int setup_earlycon(char *buf);
904#else
905static const bool earlycon_acpi_spcr_enable EARLYCON_USED_OR_UNUSED;
906static inline int setup_earlycon(char *buf) { return 0; }
907#endif
908
909/* Variant of uart_console_registered() when the console_list_lock is held. */
910static inline bool uart_console_registered_locked(struct uart_port *port)
911{
912 return uart_console(port) && console_is_registered_locked(con: port->cons);
913}
914
915static inline bool uart_console_registered(struct uart_port *port)
916{
917 return uart_console(port) && console_is_registered(con: port->cons);
918}
919
920struct uart_port *uart_get_console(struct uart_port *ports, int nr,
921 struct console *c);
922int uart_parse_earlycon(char *p, unsigned char *iotype, resource_size_t *addr,
923 char **options);
924void uart_parse_options(const char *options, int *baud, int *parity, int *bits,
925 int *flow);
926int uart_set_options(struct uart_port *port, struct console *co, int baud,
927 int parity, int bits, int flow);
928struct tty_driver *uart_console_device(struct console *co, int *index);
929void uart_console_write(struct uart_port *port, const char *s,
930 unsigned int count,
931 void (*putchar)(struct uart_port *, unsigned char));
932
933/*
934 * Port/driver registration/removal
935 */
936int uart_register_driver(struct uart_driver *uart);
937void uart_unregister_driver(struct uart_driver *uart);
938int uart_add_one_port(struct uart_driver *reg, struct uart_port *port);
939void uart_remove_one_port(struct uart_driver *reg, struct uart_port *port);
940bool uart_match_port(const struct uart_port *port1,
941 const struct uart_port *port2);
942
943/*
944 * Power Management
945 */
946int uart_suspend_port(struct uart_driver *reg, struct uart_port *port);
947int uart_resume_port(struct uart_driver *reg, struct uart_port *port);
948
949#define uart_circ_empty(circ) ((circ)->head == (circ)->tail)
950#define uart_circ_clear(circ) ((circ)->head = (circ)->tail = 0)
951
952#define uart_circ_chars_pending(circ) \
953 (CIRC_CNT((circ)->head, (circ)->tail, UART_XMIT_SIZE))
954
955#define uart_circ_chars_free(circ) \
956 (CIRC_SPACE((circ)->head, (circ)->tail, UART_XMIT_SIZE))
957
958static inline int uart_tx_stopped(struct uart_port *port)
959{
960 struct tty_struct *tty = port->state->port.tty;
961 if ((tty && tty->flow.stopped) || port->hw_stopped)
962 return 1;
963 return 0;
964}
965
966static inline bool uart_cts_enabled(struct uart_port *uport)
967{
968 return !!(uport->status & UPSTAT_CTS_ENABLE);
969}
970
971static inline bool uart_softcts_mode(struct uart_port *uport)
972{
973 upstat_t mask = UPSTAT_CTS_ENABLE | UPSTAT_AUTOCTS;
974
975 return ((uport->status & mask) == UPSTAT_CTS_ENABLE);
976}
977
978/*
979 * The following are helper functions for the low level drivers.
980 */
981
982void uart_handle_dcd_change(struct uart_port *uport, bool active);
983void uart_handle_cts_change(struct uart_port *uport, bool active);
984
985void uart_insert_char(struct uart_port *port, unsigned int status,
986 unsigned int overrun, u8 ch, u8 flag);
987
988void uart_xchar_out(struct uart_port *uport, int offset);
989
990#ifdef CONFIG_MAGIC_SYSRQ_SERIAL
991#define SYSRQ_TIMEOUT (HZ * 5)
992
993bool uart_try_toggle_sysrq(struct uart_port *port, u8 ch);
994
995static inline int uart_handle_sysrq_char(struct uart_port *port, u8 ch)
996{
997 if (!port->sysrq)
998 return 0;
999
1000 if (ch && time_before(jiffies, port->sysrq)) {
1001 if (sysrq_mask()) {
1002 handle_sysrq(key: ch);
1003 port->sysrq = 0;
1004 return 1;
1005 }
1006 if (uart_try_toggle_sysrq(port, ch))
1007 return 1;
1008 }
1009 port->sysrq = 0;
1010
1011 return 0;
1012}
1013
1014static inline int uart_prepare_sysrq_char(struct uart_port *port, u8 ch)
1015{
1016 if (!port->sysrq)
1017 return 0;
1018
1019 if (ch && time_before(jiffies, port->sysrq)) {
1020 if (sysrq_mask()) {
1021 port->sysrq_ch = ch;
1022 port->sysrq = 0;
1023 return 1;
1024 }
1025 if (uart_try_toggle_sysrq(port, ch))
1026 return 1;
1027 }
1028 port->sysrq = 0;
1029
1030 return 0;
1031}
1032
1033static inline void uart_unlock_and_check_sysrq(struct uart_port *port)
1034{
1035 u8 sysrq_ch;
1036
1037 if (!port->has_sysrq) {
1038 uart_port_unlock(up: port);
1039 return;
1040 }
1041
1042 sysrq_ch = port->sysrq_ch;
1043 port->sysrq_ch = 0;
1044
1045 uart_port_unlock(up: port);
1046
1047 if (sysrq_ch)
1048 handle_sysrq(key: sysrq_ch);
1049}
1050
1051static inline void uart_unlock_and_check_sysrq_irqrestore(struct uart_port *port,
1052 unsigned long flags)
1053{
1054 u8 sysrq_ch;
1055
1056 if (!port->has_sysrq) {
1057 uart_port_unlock_irqrestore(up: port, flags);
1058 return;
1059 }
1060
1061 sysrq_ch = port->sysrq_ch;
1062 port->sysrq_ch = 0;
1063
1064 uart_port_unlock_irqrestore(up: port, flags);
1065
1066 if (sysrq_ch)
1067 handle_sysrq(key: sysrq_ch);
1068}
1069#else /* CONFIG_MAGIC_SYSRQ_SERIAL */
1070static inline int uart_handle_sysrq_char(struct uart_port *port, u8 ch)
1071{
1072 return 0;
1073}
1074static inline int uart_prepare_sysrq_char(struct uart_port *port, u8 ch)
1075{
1076 return 0;
1077}
1078static inline void uart_unlock_and_check_sysrq(struct uart_port *port)
1079{
1080 uart_port_unlock(port);
1081}
1082static inline void uart_unlock_and_check_sysrq_irqrestore(struct uart_port *port,
1083 unsigned long flags)
1084{
1085 uart_port_unlock_irqrestore(port, flags);
1086}
1087#endif /* CONFIG_MAGIC_SYSRQ_SERIAL */
1088
1089/*
1090 * We do the SysRQ and SAK checking like this...
1091 */
1092static inline int uart_handle_break(struct uart_port *port)
1093{
1094 struct uart_state *state = port->state;
1095
1096 if (port->handle_break)
1097 port->handle_break(port);
1098
1099#ifdef CONFIG_MAGIC_SYSRQ_SERIAL
1100 if (port->has_sysrq && uart_console(port)) {
1101 if (!port->sysrq) {
1102 port->sysrq = jiffies + SYSRQ_TIMEOUT;
1103 return 1;
1104 }
1105 port->sysrq = 0;
1106 }
1107#endif
1108 if (port->flags & UPF_SAK)
1109 do_SAK(tty: state->port.tty);
1110 return 0;
1111}
1112
1113/*
1114 * UART_ENABLE_MS - determine if port should enable modem status irqs
1115 */
1116#define UART_ENABLE_MS(port,cflag) ((port)->flags & UPF_HARDPPS_CD || \
1117 (cflag) & CRTSCTS || \
1118 !((cflag) & CLOCAL))
1119
1120int uart_get_rs485_mode(struct uart_port *port);
1121#endif /* LINUX_SERIAL_CORE_H */
1122

source code of linux/include/linux/serial_core.h