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
29 struct uart_port;
30 struct serial_struct;
31 struct device;
32 struct 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 */
38 struct 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
89 struct 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
103 typedef unsigned int __bitwise upf_t;
104 typedef unsigned int __bitwise upstat_t;
105
106 struct 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
serial_port_in(struct uart_port * up,int offset)261 static inline int serial_port_in(struct uart_port *up, int offset)
262 {
263 return up->serial_in(up, offset);
264 }
265
serial_port_out(struct uart_port * up,int offset,int value)266 static 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 */
277 enum 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 */
286 struct 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
303 struct module;
304 struct tty_driver;
305
306 struct 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
323 void uart_write_wakeup(struct uart_port *port);
324
325 /*
326 * Baud rate helpers.
327 */
328 void uart_update_timeout(struct uart_port *port, unsigned int cflag,
329 unsigned int baud);
330 unsigned int uart_get_baud_rate(struct uart_port *port, struct ktermios *termios,
331 struct ktermios *old, unsigned int min,
332 unsigned int max);
333 unsigned int uart_get_divisor(struct uart_port *port, unsigned int baud);
334
335 /* Base timer interval for polling */
uart_poll_timeout(struct uart_port * port)336 static 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 */
346 struct earlycon_device {
347 struct console *con;
348 struct uart_port port;
349 char options[16]; /* e.g., 115200n8 */
350 unsigned int baud;
351 };
352
353 struct 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
360 extern const struct earlycon_id *__earlycon_table[];
361 extern 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, unique_id) \
370 static const struct earlycon_id unique_id \
371 EARLYCON_USED_OR_UNUSED __initconst \
372 = { .name = __stringify(_name), \
373 .compatible = compat, \
374 .setup = fn }; \
375 static const struct earlycon_id EARLYCON_USED_OR_UNUSED \
376 __section("__earlycon_table") \
377 * const __PASTE(__p, unique_id) = &unique_id
378
379 #define OF_EARLYCON_DECLARE(_name, compat, fn) \
380 _OF_EARLYCON_DECLARE(_name, compat, fn, \
381 __UNIQUE_ID(__earlycon_##_name))
382
383 #define EARLYCON_DECLARE(_name, fn) OF_EARLYCON_DECLARE(_name, "", fn)
384
385 extern int of_setup_earlycon(const struct earlycon_id *match,
386 unsigned long node,
387 const char *options);
388
389 #ifdef CONFIG_SERIAL_EARLYCON
390 extern bool earlycon_acpi_spcr_enable __initdata;
391 int setup_earlycon(char *buf);
392 #else
393 static const bool earlycon_acpi_spcr_enable EARLYCON_USED_OR_UNUSED;
setup_earlycon(char * buf)394 static inline int setup_earlycon(char *buf) { return 0; }
395 #endif
396
397 struct uart_port *uart_get_console(struct uart_port *ports, int nr,
398 struct console *c);
399 int uart_parse_earlycon(char *p, unsigned char *iotype, resource_size_t *addr,
400 char **options);
401 void uart_parse_options(const char *options, int *baud, int *parity, int *bits,
402 int *flow);
403 int uart_set_options(struct uart_port *port, struct console *co, int baud,
404 int parity, int bits, int flow);
405 struct tty_driver *uart_console_device(struct console *co, int *index);
406 void uart_console_write(struct uart_port *port, const char *s,
407 unsigned int count,
408 void (*putchar)(struct uart_port *, int));
409
410 /*
411 * Port/driver registration/removal
412 */
413 int uart_register_driver(struct uart_driver *uart);
414 void uart_unregister_driver(struct uart_driver *uart);
415 int uart_add_one_port(struct uart_driver *reg, struct uart_port *port);
416 int uart_remove_one_port(struct uart_driver *reg, struct uart_port *port);
417 int uart_match_port(struct uart_port *port1, struct uart_port *port2);
418
419 /*
420 * Power Management
421 */
422 int uart_suspend_port(struct uart_driver *reg, struct uart_port *port);
423 int uart_resume_port(struct uart_driver *reg, struct uart_port *port);
424
425 #define uart_circ_empty(circ) ((circ)->head == (circ)->tail)
426 #define uart_circ_clear(circ) ((circ)->head = (circ)->tail = 0)
427
428 #define uart_circ_chars_pending(circ) \
429 (CIRC_CNT((circ)->head, (circ)->tail, UART_XMIT_SIZE))
430
431 #define uart_circ_chars_free(circ) \
432 (CIRC_SPACE((circ)->head, (circ)->tail, UART_XMIT_SIZE))
433
uart_tx_stopped(struct uart_port * port)434 static inline int uart_tx_stopped(struct uart_port *port)
435 {
436 struct tty_struct *tty = port->state->port.tty;
437 if ((tty && tty->stopped) || port->hw_stopped)
438 return 1;
439 return 0;
440 }
441
uart_cts_enabled(struct uart_port * uport)442 static inline bool uart_cts_enabled(struct uart_port *uport)
443 {
444 return !!(uport->status & UPSTAT_CTS_ENABLE);
445 }
446
uart_softcts_mode(struct uart_port * uport)447 static inline bool uart_softcts_mode(struct uart_port *uport)
448 {
449 upstat_t mask = UPSTAT_CTS_ENABLE | UPSTAT_AUTOCTS;
450
451 return ((uport->status & mask) == UPSTAT_CTS_ENABLE);
452 }
453
454 /*
455 * The following are helper functions for the low level drivers.
456 */
457
458 extern void uart_handle_dcd_change(struct uart_port *uport,
459 unsigned int status);
460 extern void uart_handle_cts_change(struct uart_port *uport,
461 unsigned int status);
462
463 extern void uart_insert_char(struct uart_port *port, unsigned int status,
464 unsigned int overrun, unsigned int ch, unsigned int flag);
465
466 #ifdef CONFIG_MAGIC_SYSRQ_SERIAL
467 #define SYSRQ_TIMEOUT (HZ * 5)
468
469 bool uart_try_toggle_sysrq(struct uart_port *port, unsigned int ch);
470
uart_handle_sysrq_char(struct uart_port * port,unsigned int ch)471 static inline int uart_handle_sysrq_char(struct uart_port *port, unsigned int ch)
472 {
473 if (!port->sysrq)
474 return 0;
475
476 if (ch && time_before(jiffies, port->sysrq)) {
477 if (sysrq_mask()) {
478 handle_sysrq(ch);
479 port->sysrq = 0;
480 return 1;
481 }
482 if (uart_try_toggle_sysrq(port, ch))
483 return 1;
484 }
485 port->sysrq = 0;
486
487 return 0;
488 }
489
uart_prepare_sysrq_char(struct uart_port * port,unsigned int ch)490 static inline int uart_prepare_sysrq_char(struct uart_port *port, unsigned int ch)
491 {
492 if (!port->sysrq)
493 return 0;
494
495 if (ch && time_before(jiffies, port->sysrq)) {
496 if (sysrq_mask()) {
497 port->sysrq_ch = ch;
498 port->sysrq = 0;
499 return 1;
500 }
501 if (uart_try_toggle_sysrq(port, ch))
502 return 1;
503 }
504 port->sysrq = 0;
505
506 return 0;
507 }
508
uart_unlock_and_check_sysrq(struct uart_port * port,unsigned long irqflags)509 static inline void uart_unlock_and_check_sysrq(struct uart_port *port, unsigned long irqflags)
510 {
511 int sysrq_ch;
512
513 if (!port->has_sysrq) {
514 spin_unlock_irqrestore(&port->lock, irqflags);
515 return;
516 }
517
518 sysrq_ch = port->sysrq_ch;
519 port->sysrq_ch = 0;
520
521 spin_unlock_irqrestore(&port->lock, irqflags);
522
523 if (sysrq_ch)
524 handle_sysrq(sysrq_ch);
525 }
526 #else /* CONFIG_MAGIC_SYSRQ_SERIAL */
uart_handle_sysrq_char(struct uart_port * port,unsigned int ch)527 static inline int uart_handle_sysrq_char(struct uart_port *port, unsigned int ch)
528 {
529 return 0;
530 }
uart_prepare_sysrq_char(struct uart_port * port,unsigned int ch)531 static inline int uart_prepare_sysrq_char(struct uart_port *port, unsigned int ch)
532 {
533 return 0;
534 }
uart_unlock_and_check_sysrq(struct uart_port * port,unsigned long irqflags)535 static inline void uart_unlock_and_check_sysrq(struct uart_port *port, unsigned long irqflags)
536 {
537 spin_unlock_irqrestore(&port->lock, irqflags);
538 }
539 #endif /* CONFIG_MAGIC_SYSRQ_SERIAL */
540
541 /*
542 * We do the SysRQ and SAK checking like this...
543 */
uart_handle_break(struct uart_port * port)544 static inline int uart_handle_break(struct uart_port *port)
545 {
546 struct uart_state *state = port->state;
547
548 if (port->handle_break)
549 port->handle_break(port);
550
551 #ifdef CONFIG_MAGIC_SYSRQ_SERIAL
552 if (port->has_sysrq && uart_console(port)) {
553 if (!port->sysrq) {
554 port->sysrq = jiffies + SYSRQ_TIMEOUT;
555 return 1;
556 }
557 port->sysrq = 0;
558 }
559 #endif
560 if (port->flags & UPF_SAK)
561 do_SAK(state->port.tty);
562 return 0;
563 }
564
565 /*
566 * UART_ENABLE_MS - determine if port should enable modem status irqs
567 */
568 #define UART_ENABLE_MS(port,cflag) ((port)->flags & UPF_HARDPPS_CD || \
569 (cflag) & CRTSCTS || \
570 !((cflag) & CLOCAL))
571
572 int uart_get_rs485_mode(struct uart_port *port);
573 #endif /* LINUX_SERIAL_CORE_H */
574