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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 device;
32struct gpio_desc;
33
34/*
35 * This structure describes all the operations that can be done on the
36 * physical hardware. See Documentation/driver-api/serial/driver.rst for details.
37 */
38struct uart_ops {
39 unsigned int (*tx_empty)(struct uart_port *);
40 void (*set_mctrl)(struct uart_port *, unsigned int mctrl);
41 unsigned int (*get_mctrl)(struct uart_port *);
42 void (*stop_tx)(struct uart_port *);
43 void (*start_tx)(struct uart_port *);
44 void (*throttle)(struct uart_port *);
45 void (*unthrottle)(struct uart_port *);
46 void (*send_xchar)(struct uart_port *, char ch);
47 void (*stop_rx)(struct uart_port *);
48 void (*enable_ms)(struct uart_port *);
49 void (*break_ctl)(struct uart_port *, int ctl);
50 int (*startup)(struct uart_port *);
51 void (*shutdown)(struct uart_port *);
52 void (*flush_buffer)(struct uart_port *);
53 void (*set_termios)(struct uart_port *, struct ktermios *new,
54 struct ktermios *old);
55 void (*set_ldisc)(struct uart_port *, struct ktermios *);
56 void (*pm)(struct uart_port *, unsigned int state,
57 unsigned int oldstate);
58
59 /*
60 * Return a string describing the type of the port
61 */
62 const char *(*type)(struct uart_port *);
63
64 /*
65 * Release IO and memory resources used by the port.
66 * This includes iounmap if necessary.
67 */
68 void (*release_port)(struct uart_port *);
69
70 /*
71 * Request IO and memory resources used by the port.
72 * This includes iomapping the port if necessary.
73 */
74 int (*request_port)(struct uart_port *);
75 void (*config_port)(struct uart_port *, int);
76 int (*verify_port)(struct uart_port *, struct serial_struct *);
77 int (*ioctl)(struct uart_port *, unsigned int, unsigned long);
78#ifdef CONFIG_CONSOLE_POLL
79 int (*poll_init)(struct uart_port *);
80 void (*poll_put_char)(struct uart_port *, unsigned char);
81 int (*poll_get_char)(struct uart_port *);
82#endif
83};
84
85#define NO_POLL_CHAR 0x00ff0000
86#define UART_CONFIG_TYPE (1 << 0)
87#define UART_CONFIG_IRQ (1 << 1)
88
89struct uart_icount {
90 __u32 cts;
91 __u32 dsr;
92 __u32 rng;
93 __u32 dcd;
94 __u32 rx;
95 __u32 tx;
96 __u32 frame;
97 __u32 overrun;
98 __u32 parity;
99 __u32 brk;
100 __u32 buf_overrun;
101};
102
103typedef unsigned int __bitwise upf_t;
104typedef unsigned int __bitwise upstat_t;
105
106struct uart_port {
107 spinlock_t lock; /* port lock */
108 unsigned long iobase; /* in/out[bwl] */
109 unsigned char __iomem *membase; /* read/write[bwl] */
110 unsigned int (*serial_in)(struct uart_port *, int);
111 void (*serial_out)(struct uart_port *, int, int);
112 void (*set_termios)(struct uart_port *,
113 struct ktermios *new,
114 struct ktermios *old);
115 void (*set_ldisc)(struct uart_port *,
116 struct ktermios *);
117 unsigned int (*get_mctrl)(struct uart_port *);
118 void (*set_mctrl)(struct uart_port *, unsigned int);
119 unsigned int (*get_divisor)(struct uart_port *,
120 unsigned int baud,
121 unsigned int *frac);
122 void (*set_divisor)(struct uart_port *,
123 unsigned int baud,
124 unsigned int quot,
125 unsigned int quot_frac);
126 int (*startup)(struct uart_port *port);
127 void (*shutdown)(struct uart_port *port);
128 void (*throttle)(struct uart_port *port);
129 void (*unthrottle)(struct uart_port *port);
130 int (*handle_irq)(struct uart_port *);
131 void (*pm)(struct uart_port *, unsigned int state,
132 unsigned int old);
133 void (*handle_break)(struct uart_port *);
134 int (*rs485_config)(struct uart_port *,
135 struct serial_rs485 *rs485);
136 int (*iso7816_config)(struct uart_port *,
137 struct serial_iso7816 *iso7816);
138 unsigned int irq; /* irq number */
139 unsigned long irqflags; /* irq flags */
140 unsigned int uartclk; /* base uart clock */
141 unsigned int fifosize; /* tx fifo size */
142 unsigned char x_char; /* xon/xoff char */
143 unsigned char regshift; /* reg offset shift */
144 unsigned char iotype; /* io access style */
145 unsigned char quirks; /* internal quirks */
146
147#define UPIO_PORT (SERIAL_IO_PORT) /* 8b I/O port access */
148#define UPIO_HUB6 (SERIAL_IO_HUB6) /* Hub6 ISA card */
149#define UPIO_MEM (SERIAL_IO_MEM) /* driver-specific */
150#define UPIO_MEM32 (SERIAL_IO_MEM32) /* 32b little endian */
151#define UPIO_AU (SERIAL_IO_AU) /* Au1x00 and RT288x type IO */
152#define UPIO_TSI (SERIAL_IO_TSI) /* Tsi108/109 type IO */
153#define UPIO_MEM32BE (SERIAL_IO_MEM32BE) /* 32b big endian */
154#define UPIO_MEM16 (SERIAL_IO_MEM16) /* 16b little endian */
155
156 /* quirks must be updated while holding port mutex */
157#define UPQ_NO_TXEN_TEST BIT(0)
158
159 unsigned int read_status_mask; /* driver specific */
160 unsigned int ignore_status_mask; /* driver specific */
161 struct uart_state *state; /* pointer to parent state */
162 struct uart_icount icount; /* statistics */
163
164 struct console *cons; /* struct console, if any */
165 /* flags must be updated while holding port mutex */
166 upf_t flags;
167
168 /*
169 * These flags must be equivalent to the flags defined in
170 * include/uapi/linux/tty_flags.h which are the userspace definitions
171 * assigned from the serial_struct flags in uart_set_info()
172 * [for bit definitions in the UPF_CHANGE_MASK]
173 *
174 * Bits [0..UPF_LAST_USER] are userspace defined/visible/changeable
175 * The remaining bits are serial-core specific and not modifiable by
176 * userspace.
177 */
178#define UPF_FOURPORT ((__force upf_t) ASYNC_FOURPORT /* 1 */ )
179#define UPF_SAK ((__force upf_t) ASYNC_SAK /* 2 */ )
180#define UPF_SPD_HI ((__force upf_t) ASYNC_SPD_HI /* 4 */ )
181#define UPF_SPD_VHI ((__force upf_t) ASYNC_SPD_VHI /* 5 */ )
182#define UPF_SPD_CUST ((__force upf_t) ASYNC_SPD_CUST /* 0x0030 */ )
183#define UPF_SPD_WARP ((__force upf_t) ASYNC_SPD_WARP /* 0x1010 */ )
184#define UPF_SPD_MASK ((__force upf_t) ASYNC_SPD_MASK /* 0x1030 */ )
185#define UPF_SKIP_TEST ((__force upf_t) ASYNC_SKIP_TEST /* 6 */ )
186#define UPF_AUTO_IRQ ((__force upf_t) ASYNC_AUTO_IRQ /* 7 */ )
187#define UPF_HARDPPS_CD ((__force upf_t) ASYNC_HARDPPS_CD /* 11 */ )
188#define UPF_SPD_SHI ((__force upf_t) ASYNC_SPD_SHI /* 12 */ )
189#define UPF_LOW_LATENCY ((__force upf_t) ASYNC_LOW_LATENCY /* 13 */ )
190#define UPF_BUGGY_UART ((__force upf_t) ASYNC_BUGGY_UART /* 14 */ )
191#define UPF_MAGIC_MULTIPLIER ((__force upf_t) ASYNC_MAGIC_MULTIPLIER /* 16 */ )
192
193#define UPF_NO_THRE_TEST ((__force upf_t) (1 << 19))
194/* Port has hardware-assisted h/w flow control */
195#define UPF_AUTO_CTS ((__force upf_t) (1 << 20))
196#define UPF_AUTO_RTS ((__force upf_t) (1 << 21))
197#define UPF_HARD_FLOW ((__force upf_t) (UPF_AUTO_CTS | UPF_AUTO_RTS))
198/* Port has hardware-assisted s/w flow control */
199#define UPF_SOFT_FLOW ((__force upf_t) (1 << 22))
200#define UPF_CONS_FLOW ((__force upf_t) (1 << 23))
201#define UPF_SHARE_IRQ ((__force upf_t) (1 << 24))
202#define UPF_EXAR_EFR ((__force upf_t) (1 << 25))
203#define UPF_BUG_THRE ((__force upf_t) (1 << 26))
204/* The exact UART type is known and should not be probed. */
205#define UPF_FIXED_TYPE ((__force upf_t) (1 << 27))
206#define UPF_BOOT_AUTOCONF ((__force upf_t) (1 << 28))
207#define UPF_FIXED_PORT ((__force upf_t) (1 << 29))
208#define UPF_DEAD ((__force upf_t) (1 << 30))
209#define UPF_IOREMAP ((__force upf_t) (1 << 31))
210
211#define __UPF_CHANGE_MASK 0x17fff
212#define UPF_CHANGE_MASK ((__force upf_t) __UPF_CHANGE_MASK)
213#define UPF_USR_MASK ((__force upf_t) (UPF_SPD_MASK|UPF_LOW_LATENCY))
214
215#if __UPF_CHANGE_MASK > ASYNC_FLAGS
216#error Change mask not equivalent to userspace-visible bit defines
217#endif
218
219 /*
220 * Must hold termios_rwsem, port mutex and port lock to change;
221 * can hold any one lock to read.
222 */
223 upstat_t status;
224
225#define UPSTAT_CTS_ENABLE ((__force upstat_t) (1 << 0))
226#define UPSTAT_DCD_ENABLE ((__force upstat_t) (1 << 1))
227#define UPSTAT_AUTORTS ((__force upstat_t) (1 << 2))
228#define UPSTAT_AUTOCTS ((__force upstat_t) (1 << 3))
229#define UPSTAT_AUTOXOFF ((__force upstat_t) (1 << 4))
230#define UPSTAT_SYNC_FIFO ((__force upstat_t) (1 << 5))
231
232 int hw_stopped; /* sw-assisted CTS flow state */
233 unsigned int mctrl; /* current modem ctrl settings */
234 unsigned int timeout; /* character-based timeout */
235 unsigned int type; /* port type */
236 const struct uart_ops *ops;
237 unsigned int custom_divisor;
238 unsigned int line; /* port index */
239 unsigned int minor;
240 resource_size_t mapbase; /* for ioremap */
241 resource_size_t mapsize;
242 struct device *dev; /* parent device */
243
244 unsigned long sysrq; /* sysrq timeout */
245 unsigned int sysrq_ch; /* char for sysrq */
246 unsigned char has_sysrq;
247 unsigned char sysrq_seq; /* index in sysrq_toggle_seq */
248
249 unsigned char hub6; /* this should be in the 8250 driver */
250 unsigned char suspended;
251 unsigned char console_reinit;
252 const char *name; /* port name */
253 struct attribute_group *attr_group; /* port specific attributes */
254 const struct attribute_group **tty_groups; /* all attributes (serial core use only) */
255 struct serial_rs485 rs485;
256 struct gpio_desc *rs485_term_gpio; /* enable RS485 bus termination */
257 struct serial_iso7816 iso7816;
258 void *private_data; /* generic platform data pointer */
259};
260
261static inline int serial_port_in(struct uart_port *up, int offset)
262{
263 return up->serial_in(up, offset);
264}
265
266static inline void serial_port_out(struct uart_port *up, int offset, int value)
267{
268 up->serial_out(up, offset, value);
269}
270
271/**
272 * enum uart_pm_state - power states for UARTs
273 * @UART_PM_STATE_ON: UART is powered, up and operational
274 * @UART_PM_STATE_OFF: UART is powered off
275 * @UART_PM_STATE_UNDEFINED: sentinel
276 */
277enum uart_pm_state {
278 UART_PM_STATE_ON = 0,
279 UART_PM_STATE_OFF = 3, /* number taken from ACPI */
280 UART_PM_STATE_UNDEFINED,
281};
282
283/*
284 * This is the state information which is persistent across opens.
285 */
286struct uart_state {
287 struct tty_port port;
288
289 enum uart_pm_state pm_state;
290 struct circ_buf xmit;
291
292 atomic_t refcount;
293 wait_queue_head_t remove_wait;
294 struct uart_port *uart_port;
295};
296
297#define UART_XMIT_SIZE PAGE_SIZE
298
299
300/* number of characters left in xmit buffer before we ask for more */
301#define WAKEUP_CHARS 256
302
303struct module;
304struct tty_driver;
305
306struct uart_driver {
307 struct module *owner;
308 const char *driver_name;
309 const char *dev_name;
310 int major;
311 int minor;
312 int nr;
313 struct console *cons;
314
315 /*
316 * these are private; the low level driver should not
317 * touch these; they should be initialised to NULL
318 */
319 struct uart_state *state;
320 struct tty_driver *tty_driver;
321};
322
323void uart_write_wakeup(struct uart_port *port);
324
325/*
326 * Baud rate helpers.
327 */
328void uart_update_timeout(struct uart_port *port, unsigned int cflag,
329 unsigned int baud);
330unsigned int uart_get_baud_rate(struct uart_port *port, struct ktermios *termios,
331 struct ktermios *old, unsigned int min,
332 unsigned int max);
333unsigned int uart_get_divisor(struct uart_port *port, unsigned int baud);
334
335/* Base timer interval for polling */
336static inline int uart_poll_timeout(struct uart_port *port)
337{
338 int timeout = port->timeout;
339
340 return timeout > 6 ? (timeout / 2 - 2) : 1;
341}
342
343/*
344 * Console helpers.
345 */
346struct earlycon_device {
347 struct console *con;
348 struct uart_port port;
349 char options[16]; /* e.g., 115200n8 */
350 unsigned int baud;
351};
352
353struct earlycon_id {
354 char name[15];
355 char name_term; /* In case compiler didn't '\0' term name */
356 char compatible[128];
357 int (*setup)(struct earlycon_device *, const char *options);
358};
359
360extern const struct earlycon_id __earlycon_table[];
361extern const struct earlycon_id __earlycon_table_end[];
362
363#if defined(CONFIG_SERIAL_EARLYCON) && !defined(MODULE)
364#define EARLYCON_USED_OR_UNUSED __used
365#else
366#define EARLYCON_USED_OR_UNUSED __maybe_unused
367#endif
368
369#define OF_EARLYCON_DECLARE(_name, compat, fn) \
370 static const struct earlycon_id __UNIQUE_ID(__earlycon_##_name) \
371 EARLYCON_USED_OR_UNUSED __section("__earlycon_table") \
372 __aligned(__alignof__(struct earlycon_id)) \
373 = { .name = __stringify(_name), \
374 .compatible = compat, \
375 .setup = fn }
376
377#define EARLYCON_DECLARE(_name, fn) OF_EARLYCON_DECLARE(_name, "", fn)
378
379extern int of_setup_earlycon(const struct earlycon_id *match,
380 unsigned long node,
381 const char *options);
382
383#ifdef CONFIG_SERIAL_EARLYCON
384extern bool earlycon_acpi_spcr_enable __initdata;
385int setup_earlycon(char *buf);
386#else
387static const bool earlycon_acpi_spcr_enable EARLYCON_USED_OR_UNUSED;
388static inline int setup_earlycon(char *buf) { return 0; }
389#endif
390
391struct uart_port *uart_get_console(struct uart_port *ports, int nr,
392 struct console *c);
393int uart_parse_earlycon(char *p, unsigned char *iotype, resource_size_t *addr,
394 char **options);
395void uart_parse_options(const char *options, int *baud, int *parity, int *bits,
396 int *flow);
397int uart_set_options(struct uart_port *port, struct console *co, int baud,
398 int parity, int bits, int flow);
399struct tty_driver *uart_console_device(struct console *co, int *index);
400void uart_console_write(struct uart_port *port, const char *s,
401 unsigned int count,
402 void (*putchar)(struct uart_port *, int));
403
404/*
405 * Port/driver registration/removal
406 */
407int uart_register_driver(struct uart_driver *uart);
408void uart_unregister_driver(struct uart_driver *uart);
409int uart_add_one_port(struct uart_driver *reg, struct uart_port *port);
410int uart_remove_one_port(struct uart_driver *reg, struct uart_port *port);
411bool uart_match_port(const struct uart_port *port1,
412 const struct uart_port *port2);
413
414/*
415 * Power Management
416 */
417int uart_suspend_port(struct uart_driver *reg, struct uart_port *port);
418int uart_resume_port(struct uart_driver *reg, struct uart_port *port);
419
420#define uart_circ_empty(circ) ((circ)->head == (circ)->tail)
421#define uart_circ_clear(circ) ((circ)->head = (circ)->tail = 0)
422
423#define uart_circ_chars_pending(circ) \
424 (CIRC_CNT((circ)->head, (circ)->tail, UART_XMIT_SIZE))
425
426#define uart_circ_chars_free(circ) \
427 (CIRC_SPACE((circ)->head, (circ)->tail, UART_XMIT_SIZE))
428
429static inline int uart_tx_stopped(struct uart_port *port)
430{
431 struct tty_struct *tty = port->state->port.tty;
432 if ((tty && tty->flow.stopped) || port->hw_stopped)
433 return 1;
434 return 0;
435}
436
437static inline bool uart_cts_enabled(struct uart_port *uport)
438{
439 return !!(uport->status & UPSTAT_CTS_ENABLE);
440}
441
442static inline bool uart_softcts_mode(struct uart_port *uport)
443{
444 upstat_t mask = UPSTAT_CTS_ENABLE | UPSTAT_AUTOCTS;
445
446 return ((uport->status & mask) == UPSTAT_CTS_ENABLE);
447}
448
449/*
450 * The following are helper functions for the low level drivers.
451 */
452
453extern void uart_handle_dcd_change(struct uart_port *uport,
454 unsigned int status);
455extern void uart_handle_cts_change(struct uart_port *uport,
456 unsigned int status);
457
458extern void uart_insert_char(struct uart_port *port, unsigned int status,
459 unsigned int overrun, unsigned int ch, unsigned int flag);
460
461#ifdef CONFIG_MAGIC_SYSRQ_SERIAL
462#define SYSRQ_TIMEOUT (HZ * 5)
463
464bool uart_try_toggle_sysrq(struct uart_port *port, unsigned int ch);
465
466static inline int uart_handle_sysrq_char(struct uart_port *port, unsigned int ch)
467{
468 if (!port->sysrq)
469 return 0;
470
471 if (ch && time_before(jiffies, port->sysrq)) {
472 if (sysrq_mask()) {
473 handle_sysrq(ch);
474 port->sysrq = 0;
475 return 1;
476 }
477 if (uart_try_toggle_sysrq(port, ch))
478 return 1;
479 }
480 port->sysrq = 0;
481
482 return 0;
483}
484
485static inline int uart_prepare_sysrq_char(struct uart_port *port, unsigned int ch)
486{
487 if (!port->sysrq)
488 return 0;
489
490 if (ch && time_before(jiffies, port->sysrq)) {
491 if (sysrq_mask()) {
492 port->sysrq_ch = ch;
493 port->sysrq = 0;
494 return 1;
495 }
496 if (uart_try_toggle_sysrq(port, ch))
497 return 1;
498 }
499 port->sysrq = 0;
500
501 return 0;
502}
503
504static inline void uart_unlock_and_check_sysrq(struct uart_port *port)
505{
506 int sysrq_ch;
507
508 if (!port->has_sysrq) {
509 spin_unlock(&port->lock);
510 return;
511 }
512
513 sysrq_ch = port->sysrq_ch;
514 port->sysrq_ch = 0;
515
516 spin_unlock(&port->lock);
517
518 if (sysrq_ch)
519 handle_sysrq(sysrq_ch);
520}
521
522static inline void uart_unlock_and_check_sysrq_irqrestore(struct uart_port *port,
523 unsigned long flags)
524{
525 int sysrq_ch;
526
527 if (!port->has_sysrq) {
528 spin_unlock_irqrestore(&port->lock, flags);
529 return;
530 }
531
532 sysrq_ch = port->sysrq_ch;
533 port->sysrq_ch = 0;
534
535 spin_unlock_irqrestore(&port->lock, flags);
536
537 if (sysrq_ch)
538 handle_sysrq(sysrq_ch);
539}
540#else /* CONFIG_MAGIC_SYSRQ_SERIAL */
541static inline int uart_handle_sysrq_char(struct uart_port *port, unsigned int ch)
542{
543 return 0;
544}
545static inline int uart_prepare_sysrq_char(struct uart_port *port, unsigned int ch)
546{
547 return 0;
548}
549static inline void uart_unlock_and_check_sysrq(struct uart_port *port)
550{
551 spin_unlock(&port->lock);
552}
553static inline void uart_unlock_and_check_sysrq_irqrestore(struct uart_port *port,
554 unsigned long flags)
555{
556 spin_unlock_irqrestore(&port->lock, flags);
557}
558#endif /* CONFIG_MAGIC_SYSRQ_SERIAL */
559
560/*
561 * We do the SysRQ and SAK checking like this...
562 */
563static inline int uart_handle_break(struct uart_port *port)
564{
565 struct uart_state *state = port->state;
566
567 if (port->handle_break)
568 port->handle_break(port);
569
570#ifdef CONFIG_MAGIC_SYSRQ_SERIAL
571 if (port->has_sysrq && uart_console(port)) {
572 if (!port->sysrq) {
573 port->sysrq = jiffies + SYSRQ_TIMEOUT;
574 return 1;
575 }
576 port->sysrq = 0;
577 }
578#endif
579 if (port->flags & UPF_SAK)
580 do_SAK(state->port.tty);
581 return 0;
582}
583
584/*
585 * UART_ENABLE_MS - determine if port should enable modem status irqs
586 */
587#define UART_ENABLE_MS(port,cflag) ((port)->flags & UPF_HARDPPS_CD || \
588 (cflag) & CRTSCTS || \
589 !((cflag) & CLOCAL))
590
591int uart_get_rs485_mode(struct uart_port *port);
592#endif /* LINUX_SERIAL_CORE_H */
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
471 unsigned char iotype; /* io access style */
472
473#define UPIO_UNKNOWN ((unsigned char)~0U) /* UCHAR_MAX */
474#define UPIO_PORT (SERIAL_IO_PORT) /* 8b I/O port access */
475#define UPIO_HUB6 (SERIAL_IO_HUB6) /* Hub6 ISA card */
476#define UPIO_MEM (SERIAL_IO_MEM) /* driver-specific */
477#define UPIO_MEM32 (SERIAL_IO_MEM32) /* 32b little endian */
478#define UPIO_AU (SERIAL_IO_AU) /* Au1x00 and RT288x type IO */
479#define UPIO_TSI (SERIAL_IO_TSI) /* Tsi108/109 type IO */
480#define UPIO_MEM32BE (SERIAL_IO_MEM32BE) /* 32b big endian */
481#define UPIO_MEM16 (SERIAL_IO_MEM16) /* 16b little endian */
482
483 unsigned char quirks; /* internal quirks */
484
485 /* internal quirks must be updated while holding port mutex */
486#define UPQ_NO_TXEN_TEST BIT(0)
487
488 unsigned int read_status_mask; /* driver specific */
489 unsigned int ignore_status_mask; /* driver specific */
490 struct uart_state *state; /* pointer to parent state */
491 struct uart_icount icount; /* statistics */
492
493 struct console *cons; /* struct console, if any */
494 /* flags must be updated while holding port mutex */
495 upf_t flags;
496
497 /*
498 * These flags must be equivalent to the flags defined in
499 * include/uapi/linux/tty_flags.h which are the userspace definitions
500 * assigned from the serial_struct flags in uart_set_info()
501 * [for bit definitions in the UPF_CHANGE_MASK]
502 *
503 * Bits [0..ASYNCB_LAST_USER] are userspace defined/visible/changeable
504 * The remaining bits are serial-core specific and not modifiable by
505 * userspace.
506 */
507#define UPF_FOURPORT ((__force upf_t) ASYNC_FOURPORT /* 1 */ )
508#define UPF_SAK ((__force upf_t) ASYNC_SAK /* 2 */ )
509#define UPF_SPD_HI ((__force upf_t) ASYNC_SPD_HI /* 4 */ )
510#define UPF_SPD_VHI ((__force upf_t) ASYNC_SPD_VHI /* 5 */ )
511#define UPF_SPD_CUST ((__force upf_t) ASYNC_SPD_CUST /* 0x0030 */ )
512#define UPF_SPD_WARP ((__force upf_t) ASYNC_SPD_WARP /* 0x1010 */ )
513#define UPF_SPD_MASK ((__force upf_t) ASYNC_SPD_MASK /* 0x1030 */ )
514#define UPF_SKIP_TEST ((__force upf_t) ASYNC_SKIP_TEST /* 6 */ )
515#define UPF_AUTO_IRQ ((__force upf_t) ASYNC_AUTO_IRQ /* 7 */ )
516#define UPF_HARDPPS_CD ((__force upf_t) ASYNC_HARDPPS_CD /* 11 */ )
517#define UPF_SPD_SHI ((__force upf_t) ASYNC_SPD_SHI /* 12 */ )
518#define UPF_LOW_LATENCY ((__force upf_t) ASYNC_LOW_LATENCY /* 13 */ )
519#define UPF_BUGGY_UART ((__force upf_t) ASYNC_BUGGY_UART /* 14 */ )
520#define UPF_MAGIC_MULTIPLIER ((__force upf_t) ASYNC_MAGIC_MULTIPLIER /* 16 */ )
521
522#define UPF_NO_THRE_TEST ((__force upf_t) BIT_ULL(19))
523/* Port has hardware-assisted h/w flow control */
524#define UPF_AUTO_CTS ((__force upf_t) BIT_ULL(20))
525#define UPF_AUTO_RTS ((__force upf_t) BIT_ULL(21))
526#define UPF_HARD_FLOW ((__force upf_t) (UPF_AUTO_CTS | UPF_AUTO_RTS))
527/* Port has hardware-assisted s/w flow control */
528#define UPF_SOFT_FLOW ((__force upf_t) BIT_ULL(22))
529#define UPF_CONS_FLOW ((__force upf_t) BIT_ULL(23))
530#define UPF_SHARE_IRQ ((__force upf_t) BIT_ULL(24))
531#define UPF_EXAR_EFR ((__force upf_t) BIT_ULL(25))
532#define UPF_BUG_THRE ((__force upf_t) BIT_ULL(26))
533/* The exact UART type is known and should not be probed. */
534#define UPF_FIXED_TYPE ((__force upf_t) BIT_ULL(27))
535#define UPF_BOOT_AUTOCONF ((__force upf_t) BIT_ULL(28))
536#define UPF_FIXED_PORT ((__force upf_t) BIT_ULL(29))
537#define UPF_DEAD ((__force upf_t) BIT_ULL(30))
538#define UPF_IOREMAP ((__force upf_t) BIT_ULL(31))
539#define UPF_FULL_PROBE ((__force upf_t) BIT_ULL(32))
540
541#define __UPF_CHANGE_MASK 0x17fff
542#define UPF_CHANGE_MASK ((__force upf_t) __UPF_CHANGE_MASK)
543#define UPF_USR_MASK ((__force upf_t) (UPF_SPD_MASK|UPF_LOW_LATENCY))
544
545#if __UPF_CHANGE_MASK > ASYNC_FLAGS
546#error Change mask not equivalent to userspace-visible bit defines
547#endif
548
549 /*
550 * Must hold termios_rwsem, port mutex and port lock to change;
551 * can hold any one lock to read.
552 */
553 upstat_t status;
554
555#define UPSTAT_CTS_ENABLE ((__force upstat_t) (1 << 0))
556#define UPSTAT_DCD_ENABLE ((__force upstat_t) (1 << 1))
557#define UPSTAT_AUTORTS ((__force upstat_t) (1 << 2))
558#define UPSTAT_AUTOCTS ((__force upstat_t) (1 << 3))
559#define UPSTAT_AUTOXOFF ((__force upstat_t) (1 << 4))
560#define UPSTAT_SYNC_FIFO ((__force upstat_t) (1 << 5))
561
562 bool hw_stopped; /* sw-assisted CTS flow state */
563 unsigned int mctrl; /* current modem ctrl settings */
564 unsigned int frame_time; /* frame timing in ns */
565 unsigned int type; /* port type */
566 const struct uart_ops *ops;
567 unsigned int custom_divisor;
568 unsigned int line; /* port index */
569 unsigned int minor;
570 resource_size_t mapbase; /* for ioremap */
571 resource_size_t mapsize;
572 struct device *dev; /* serial port physical parent device */
573 struct serial_port_device *port_dev; /* serial core port device */
574
575 unsigned long sysrq; /* sysrq timeout */
576 u8 sysrq_ch; /* char for sysrq */
577 unsigned char has_sysrq;
578 unsigned char sysrq_seq; /* index in sysrq_toggle_seq */
579
580 unsigned char hub6; /* this should be in the 8250 driver */
581 unsigned char suspended;
582 unsigned char console_reinit;
583 const char *name; /* port name */
584 struct attribute_group *attr_group; /* port specific attributes */
585 const struct attribute_group **tty_groups; /* all attributes (serial core use only) */
586 struct serial_rs485 rs485;
587 struct serial_rs485 rs485_supported; /* Supported mask for serial_rs485 */
588 struct gpio_desc *rs485_term_gpio; /* enable RS485 bus termination */
589 struct gpio_desc *rs485_rx_during_tx_gpio; /* Output GPIO that sets the state of RS485 RX during TX */
590 struct serial_iso7816 iso7816;
591 void *private_data; /* generic platform data pointer */
592};
593
594/**
595 * uart_port_lock - Lock the UART port
596 * @up: Pointer to UART port structure
597 */
598static inline void uart_port_lock(struct uart_port *up)
599{
600 spin_lock(&up->lock);
601}
602
603/**
604 * uart_port_lock_irq - Lock the UART port and disable interrupts
605 * @up: Pointer to UART port structure
606 */
607static inline void uart_port_lock_irq(struct uart_port *up)
608{
609 spin_lock_irq(&up->lock);
610}
611
612/**
613 * uart_port_lock_irqsave - Lock the UART port, save and disable interrupts
614 * @up: Pointer to UART port structure
615 * @flags: Pointer to interrupt flags storage
616 */
617static inline void uart_port_lock_irqsave(struct uart_port *up, unsigned long *flags)
618{
619 spin_lock_irqsave(&up->lock, *flags);
620}
621
622/**
623 * uart_port_trylock - Try to lock the UART port
624 * @up: Pointer to UART port structure
625 *
626 * Returns: True if lock was acquired, false otherwise
627 */
628static inline bool uart_port_trylock(struct uart_port *up)
629{
630 return spin_trylock(&up->lock);
631}
632
633/**
634 * uart_port_trylock_irqsave - Try to lock the UART port, save and disable interrupts
635 * @up: Pointer to UART port structure
636 * @flags: Pointer to interrupt flags storage
637 *
638 * Returns: True if lock was acquired, false otherwise
639 */
640static inline bool uart_port_trylock_irqsave(struct uart_port *up, unsigned long *flags)
641{
642 return spin_trylock_irqsave(&up->lock, *flags);
643}
644
645/**
646 * uart_port_unlock - Unlock the UART port
647 * @up: Pointer to UART port structure
648 */
649static inline void uart_port_unlock(struct uart_port *up)
650{
651 spin_unlock(&up->lock);
652}
653
654/**
655 * uart_port_unlock_irq - Unlock the UART port and re-enable interrupts
656 * @up: Pointer to UART port structure
657 */
658static inline void uart_port_unlock_irq(struct uart_port *up)
659{
660 spin_unlock_irq(&up->lock);
661}
662
663/**
664 * uart_port_unlock_irqrestore - Unlock the UART port, restore interrupts
665 * @up: Pointer to UART port structure
666 * @flags: The saved interrupt flags for restore
667 */
668static inline void uart_port_unlock_irqrestore(struct uart_port *up, unsigned long flags)
669{
670 spin_unlock_irqrestore(&up->lock, flags);
671}
672
673static inline int serial_port_in(struct uart_port *up, int offset)
674{
675 return up->serial_in(up, offset);
676}
677
678static inline void serial_port_out(struct uart_port *up, int offset, int value)
679{
680 up->serial_out(up, offset, value);
681}
682
683/**
684 * enum uart_pm_state - power states for UARTs
685 * @UART_PM_STATE_ON: UART is powered, up and operational
686 * @UART_PM_STATE_OFF: UART is powered off
687 * @UART_PM_STATE_UNDEFINED: sentinel
688 */
689enum uart_pm_state {
690 UART_PM_STATE_ON = 0,
691 UART_PM_STATE_OFF = 3, /* number taken from ACPI */
692 UART_PM_STATE_UNDEFINED,
693};
694
695/*
696 * This is the state information which is persistent across opens.
697 */
698struct uart_state {
699 struct tty_port port;
700
701 enum uart_pm_state pm_state;
702 struct circ_buf xmit;
703
704 atomic_t refcount;
705 wait_queue_head_t remove_wait;
706 struct uart_port *uart_port;
707};
708
709#define UART_XMIT_SIZE PAGE_SIZE
710
711
712/* number of characters left in xmit buffer before we ask for more */
713#define WAKEUP_CHARS 256
714
715/**
716 * uart_xmit_advance - Advance xmit buffer and account Tx'ed chars
717 * @up: uart_port structure describing the port
718 * @chars: number of characters sent
719 *
720 * This function advances the tail of circular xmit buffer by the number of
721 * @chars transmitted and handles accounting of transmitted bytes (into
722 * @up's icount.tx).
723 */
724static inline void uart_xmit_advance(struct uart_port *up, unsigned int chars)
725{
726 struct circ_buf *xmit = &up->state->xmit;
727
728 xmit->tail = (xmit->tail + chars) & (UART_XMIT_SIZE - 1);
729 up->icount.tx += chars;
730}
731
732struct module;
733struct tty_driver;
734
735struct uart_driver {
736 struct module *owner;
737 const char *driver_name;
738 const char *dev_name;
739 int major;
740 int minor;
741 int nr;
742 struct console *cons;
743
744 /*
745 * these are private; the low level driver should not
746 * touch these; they should be initialised to NULL
747 */
748 struct uart_state *state;
749 struct tty_driver *tty_driver;
750};
751
752void uart_write_wakeup(struct uart_port *port);
753
754/**
755 * enum UART_TX_FLAGS -- flags for uart_port_tx_flags()
756 *
757 * @UART_TX_NOSTOP: don't call port->ops->stop_tx() on empty buffer
758 */
759enum UART_TX_FLAGS {
760 UART_TX_NOSTOP = BIT(0),
761};
762
763#define __uart_port_tx(uport, ch, flags, tx_ready, put_char, tx_done, \
764 for_test, for_post) \
765({ \
766 struct uart_port *__port = (uport); \
767 struct circ_buf *xmit = &__port->state->xmit; \
768 unsigned int pending; \
769 \
770 for (; (for_test) && (tx_ready); (for_post), __port->icount.tx++) { \
771 if (__port->x_char) { \
772 (ch) = __port->x_char; \
773 (put_char); \
774 __port->x_char = 0; \
775 continue; \
776 } \
777 \
778 if (uart_circ_empty(xmit) || uart_tx_stopped(__port)) \
779 break; \
780 \
781 (ch) = xmit->buf[xmit->tail]; \
782 (put_char); \
783 xmit->tail = (xmit->tail + 1) % UART_XMIT_SIZE; \
784 } \
785 \
786 (tx_done); \
787 \
788 pending = uart_circ_chars_pending(xmit); \
789 if (pending < WAKEUP_CHARS) { \
790 uart_write_wakeup(__port); \
791 \
792 if (!((flags) & UART_TX_NOSTOP) && pending == 0 && \
793 __port->ops->tx_empty(__port)) \
794 __port->ops->stop_tx(__port); \
795 } \
796 \
797 pending; \
798})
799
800/**
801 * uart_port_tx_limited -- transmit helper for uart_port with count limiting
802 * @port: uart port
803 * @ch: variable to store a character to be written to the HW
804 * @count: a limit of characters to send
805 * @tx_ready: can HW accept more data function
806 * @put_char: function to write a character
807 * @tx_done: function to call after the loop is done
808 *
809 * This helper transmits characters from the xmit buffer to the hardware using
810 * @put_char(). It does so until @count characters are sent and while @tx_ready
811 * evaluates to true.
812 *
813 * Returns: the number of characters in the xmit buffer when done.
814 *
815 * The expression in macro parameters shall be designed as follows:
816 * * **tx_ready:** should evaluate to true if the HW can accept more data to
817 * be sent. This parameter can be %true, which means the HW is always ready.
818 * * **put_char:** shall write @ch to the device of @port.
819 * * **tx_done:** when the write loop is done, this can perform arbitrary
820 * action before potential invocation of ops->stop_tx() happens. If the
821 * driver does not need to do anything, use e.g. ({}).
822 *
823 * For all of them, @port->lock is held, interrupts are locally disabled and
824 * the expressions must not sleep.
825 */
826#define uart_port_tx_limited(port, ch, count, tx_ready, put_char, tx_done) ({ \
827 unsigned int __count = (count); \
828 __uart_port_tx(port, ch, 0, tx_ready, put_char, tx_done, __count, \
829 __count--); \
830})
831
832/**
833 * uart_port_tx -- transmit helper for uart_port
834 * @port: uart port
835 * @ch: variable to store a character to be written to the HW
836 * @tx_ready: can HW accept more data function
837 * @put_char: function to write a character
838 *
839 * See uart_port_tx_limited() for more details.
840 */
841#define uart_port_tx(port, ch, tx_ready, put_char) \
842 __uart_port_tx(port, ch, 0, tx_ready, put_char, ({}), true, ({}))
843
844
845/**
846 * uart_port_tx_flags -- transmit helper for uart_port with flags
847 * @port: uart port
848 * @ch: variable to store a character to be written to the HW
849 * @flags: %UART_TX_NOSTOP or similar
850 * @tx_ready: can HW accept more data function
851 * @put_char: function to write a character
852 *
853 * See uart_port_tx_limited() for more details.
854 */
855#define uart_port_tx_flags(port, ch, flags, tx_ready, put_char) \
856 __uart_port_tx(port, ch, flags, tx_ready, put_char, ({}), true, ({}))
857/*
858 * Baud rate helpers.
859 */
860void uart_update_timeout(struct uart_port *port, unsigned int cflag,
861 unsigned int baud);
862unsigned int uart_get_baud_rate(struct uart_port *port, struct ktermios *termios,
863 const struct ktermios *old, unsigned int min,
864 unsigned int max);
865unsigned int uart_get_divisor(struct uart_port *port, unsigned int baud);
866
867/*
868 * Calculates FIFO drain time.
869 */
870static inline unsigned long uart_fifo_timeout(struct uart_port *port)
871{
872 u64 fifo_timeout = (u64)READ_ONCE(port->frame_time) * port->fifosize;
873
874 /* Add .02 seconds of slop */
875 fifo_timeout += 20 * NSEC_PER_MSEC;
876
877 return max(nsecs_to_jiffies(fifo_timeout), 1UL);
878}
879
880/* Base timer interval for polling */
881static inline unsigned long uart_poll_timeout(struct uart_port *port)
882{
883 unsigned long timeout = uart_fifo_timeout(port);
884
885 return timeout > 6 ? (timeout / 2 - 2) : 1;
886}
887
888/*
889 * Console helpers.
890 */
891struct earlycon_device {
892 struct console *con;
893 struct uart_port port;
894 char options[32]; /* e.g., 115200n8 */
895 unsigned int baud;
896};
897
898struct earlycon_id {
899 char name[15];
900 char name_term; /* In case compiler didn't '\0' term name */
901 char compatible[128];
902 int (*setup)(struct earlycon_device *, const char *options);
903};
904
905extern const struct earlycon_id __earlycon_table[];
906extern const struct earlycon_id __earlycon_table_end[];
907
908#if defined(CONFIG_SERIAL_EARLYCON) && !defined(MODULE)
909#define EARLYCON_USED_OR_UNUSED __used
910#else
911#define EARLYCON_USED_OR_UNUSED __maybe_unused
912#endif
913
914#define OF_EARLYCON_DECLARE(_name, compat, fn) \
915 static const struct earlycon_id __UNIQUE_ID(__earlycon_##_name) \
916 EARLYCON_USED_OR_UNUSED __section("__earlycon_table") \
917 __aligned(__alignof__(struct earlycon_id)) \
918 = { .name = __stringify(_name), \
919 .compatible = compat, \
920 .setup = fn }
921
922#define EARLYCON_DECLARE(_name, fn) OF_EARLYCON_DECLARE(_name, "", fn)
923
924int of_setup_earlycon(const struct earlycon_id *match, unsigned long node,
925 const char *options);
926
927#ifdef CONFIG_SERIAL_EARLYCON
928extern bool earlycon_acpi_spcr_enable __initdata;
929int setup_earlycon(char *buf);
930#else
931static const bool earlycon_acpi_spcr_enable EARLYCON_USED_OR_UNUSED;
932static inline int setup_earlycon(char *buf) { return 0; }
933#endif
934
935/* Variant of uart_console_registered() when the console_list_lock is held. */
936static inline bool uart_console_registered_locked(struct uart_port *port)
937{
938 return uart_console(port) && console_is_registered_locked(port->cons);
939}
940
941static inline bool uart_console_registered(struct uart_port *port)
942{
943 return uart_console(port) && console_is_registered(port->cons);
944}
945
946struct uart_port *uart_get_console(struct uart_port *ports, int nr,
947 struct console *c);
948int uart_parse_earlycon(char *p, unsigned char *iotype, resource_size_t *addr,
949 char **options);
950void uart_parse_options(const char *options, int *baud, int *parity, int *bits,
951 int *flow);
952int uart_set_options(struct uart_port *port, struct console *co, int baud,
953 int parity, int bits, int flow);
954struct tty_driver *uart_console_device(struct console *co, int *index);
955void uart_console_write(struct uart_port *port, const char *s,
956 unsigned int count,
957 void (*putchar)(struct uart_port *, unsigned char));
958
959/*
960 * Port/driver registration/removal
961 */
962int uart_register_driver(struct uart_driver *uart);
963void uart_unregister_driver(struct uart_driver *uart);
964int uart_add_one_port(struct uart_driver *reg, struct uart_port *port);
965void uart_remove_one_port(struct uart_driver *reg, struct uart_port *port);
966int uart_read_port_properties(struct uart_port *port);
967int uart_read_and_validate_port_properties(struct uart_port *port);
968bool uart_match_port(const struct uart_port *port1,
969 const struct uart_port *port2);
970
971/*
972 * Power Management
973 */
974int uart_suspend_port(struct uart_driver *reg, struct uart_port *port);
975int uart_resume_port(struct uart_driver *reg, struct uart_port *port);
976
977#define uart_circ_empty(circ) ((circ)->head == (circ)->tail)
978#define uart_circ_clear(circ) ((circ)->head = (circ)->tail = 0)
979
980#define uart_circ_chars_pending(circ) \
981 (CIRC_CNT((circ)->head, (circ)->tail, UART_XMIT_SIZE))
982
983#define uart_circ_chars_free(circ) \
984 (CIRC_SPACE((circ)->head, (circ)->tail, UART_XMIT_SIZE))
985
986static inline int uart_tx_stopped(struct uart_port *port)
987{
988 struct tty_struct *tty = port->state->port.tty;
989 if ((tty && tty->flow.stopped) || port->hw_stopped)
990 return 1;
991 return 0;
992}
993
994static inline bool uart_cts_enabled(struct uart_port *uport)
995{
996 return !!(uport->status & UPSTAT_CTS_ENABLE);
997}
998
999static inline bool uart_softcts_mode(struct uart_port *uport)
1000{
1001 upstat_t mask = UPSTAT_CTS_ENABLE | UPSTAT_AUTOCTS;
1002
1003 return ((uport->status & mask) == UPSTAT_CTS_ENABLE);
1004}
1005
1006/*
1007 * The following are helper functions for the low level drivers.
1008 */
1009
1010void uart_handle_dcd_change(struct uart_port *uport, bool active);
1011void uart_handle_cts_change(struct uart_port *uport, bool active);
1012
1013void uart_insert_char(struct uart_port *port, unsigned int status,
1014 unsigned int overrun, u8 ch, u8 flag);
1015
1016void uart_xchar_out(struct uart_port *uport, int offset);
1017
1018#ifdef CONFIG_MAGIC_SYSRQ_SERIAL
1019#define SYSRQ_TIMEOUT (HZ * 5)
1020
1021bool uart_try_toggle_sysrq(struct uart_port *port, u8 ch);
1022
1023static inline int uart_handle_sysrq_char(struct uart_port *port, u8 ch)
1024{
1025 if (!port->sysrq)
1026 return 0;
1027
1028 if (ch && time_before(jiffies, port->sysrq)) {
1029 if (sysrq_mask()) {
1030 handle_sysrq(ch);
1031 port->sysrq = 0;
1032 return 1;
1033 }
1034 if (uart_try_toggle_sysrq(port, ch))
1035 return 1;
1036 }
1037 port->sysrq = 0;
1038
1039 return 0;
1040}
1041
1042static inline int uart_prepare_sysrq_char(struct uart_port *port, u8 ch)
1043{
1044 if (!port->sysrq)
1045 return 0;
1046
1047 if (ch && time_before(jiffies, port->sysrq)) {
1048 if (sysrq_mask()) {
1049 port->sysrq_ch = ch;
1050 port->sysrq = 0;
1051 return 1;
1052 }
1053 if (uart_try_toggle_sysrq(port, ch))
1054 return 1;
1055 }
1056 port->sysrq = 0;
1057
1058 return 0;
1059}
1060
1061static inline void uart_unlock_and_check_sysrq(struct uart_port *port)
1062{
1063 u8 sysrq_ch;
1064
1065 if (!port->has_sysrq) {
1066 uart_port_unlock(port);
1067 return;
1068 }
1069
1070 sysrq_ch = port->sysrq_ch;
1071 port->sysrq_ch = 0;
1072
1073 uart_port_unlock(port);
1074
1075 if (sysrq_ch)
1076 handle_sysrq(sysrq_ch);
1077}
1078
1079static inline void uart_unlock_and_check_sysrq_irqrestore(struct uart_port *port,
1080 unsigned long flags)
1081{
1082 u8 sysrq_ch;
1083
1084 if (!port->has_sysrq) {
1085 uart_port_unlock_irqrestore(port, flags);
1086 return;
1087 }
1088
1089 sysrq_ch = port->sysrq_ch;
1090 port->sysrq_ch = 0;
1091
1092 uart_port_unlock_irqrestore(port, flags);
1093
1094 if (sysrq_ch)
1095 handle_sysrq(sysrq_ch);
1096}
1097#else /* CONFIG_MAGIC_SYSRQ_SERIAL */
1098static inline int uart_handle_sysrq_char(struct uart_port *port, u8 ch)
1099{
1100 return 0;
1101}
1102static inline int uart_prepare_sysrq_char(struct uart_port *port, u8 ch)
1103{
1104 return 0;
1105}
1106static inline void uart_unlock_and_check_sysrq(struct uart_port *port)
1107{
1108 uart_port_unlock(port);
1109}
1110static inline void uart_unlock_and_check_sysrq_irqrestore(struct uart_port *port,
1111 unsigned long flags)
1112{
1113 uart_port_unlock_irqrestore(port, flags);
1114}
1115#endif /* CONFIG_MAGIC_SYSRQ_SERIAL */
1116
1117/*
1118 * We do the SysRQ and SAK checking like this...
1119 */
1120static inline int uart_handle_break(struct uart_port *port)
1121{
1122 struct uart_state *state = port->state;
1123
1124 if (port->handle_break)
1125 port->handle_break(port);
1126
1127#ifdef CONFIG_MAGIC_SYSRQ_SERIAL
1128 if (port->has_sysrq && uart_console(port)) {
1129 if (!port->sysrq) {
1130 port->sysrq = jiffies + SYSRQ_TIMEOUT;
1131 return 1;
1132 }
1133 port->sysrq = 0;
1134 }
1135#endif
1136 if (port->flags & UPF_SAK)
1137 do_SAK(state->port.tty);
1138 return 0;
1139}
1140
1141/*
1142 * UART_ENABLE_MS - determine if port should enable modem status irqs
1143 */
1144#define UART_ENABLE_MS(port,cflag) ((port)->flags & UPF_HARDPPS_CD || \
1145 (cflag) & CRTSCTS || \
1146 !((cflag) & CLOCAL))
1147
1148int uart_get_rs485_mode(struct uart_port *port);
1149#endif /* LINUX_SERIAL_CORE_H */