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
33 /*
34 * This structure describes all the operations that can be done on the
35 * physical hardware. See Documentation/driver-api/serial/driver.rst for details.
36 */
37 struct uart_ops {
38 unsigned int (*tx_empty)(struct uart_port *);
39 void (*set_mctrl)(struct uart_port *, unsigned int mctrl);
40 unsigned int (*get_mctrl)(struct uart_port *);
41 void (*stop_tx)(struct uart_port *);
42 void (*start_tx)(struct uart_port *);
43 void (*throttle)(struct uart_port *);
44 void (*unthrottle)(struct uart_port *);
45 void (*send_xchar)(struct uart_port *, char ch);
46 void (*stop_rx)(struct uart_port *);
47 void (*enable_ms)(struct uart_port *);
48 void (*break_ctl)(struct uart_port *, int ctl);
49 int (*startup)(struct uart_port *);
50 void (*shutdown)(struct uart_port *);
51 void (*flush_buffer)(struct uart_port *);
52 void (*set_termios)(struct uart_port *, struct ktermios *new,
53 struct ktermios *old);
54 void (*set_ldisc)(struct uart_port *, struct ktermios *);
55 void (*pm)(struct uart_port *, unsigned int state,
56 unsigned int oldstate);
57
58 /*
59 * Return a string describing the type of the port
60 */
61 const char *(*type)(struct uart_port *);
62
63 /*
64 * Release IO and memory resources used by the port.
65 * This includes iounmap if necessary.
66 */
67 void (*release_port)(struct uart_port *);
68
69 /*
70 * Request IO and memory resources used by the port.
71 * This includes iomapping the port if necessary.
72 */
73 int (*request_port)(struct uart_port *);
74 void (*config_port)(struct uart_port *, int);
75 int (*verify_port)(struct uart_port *, struct serial_struct *);
76 int (*ioctl)(struct uart_port *, unsigned int, unsigned long);
77 #ifdef CONFIG_CONSOLE_POLL
78 int (*poll_init)(struct uart_port *);
79 void (*poll_put_char)(struct uart_port *, unsigned char);
80 int (*poll_get_char)(struct uart_port *);
81 #endif
82 };
83
84 #define NO_POLL_CHAR 0x00ff0000
85 #define UART_CONFIG_TYPE (1 << 0)
86 #define UART_CONFIG_IRQ (1 << 1)
87
88 struct uart_icount {
89 __u32 cts;
90 __u32 dsr;
91 __u32 rng;
92 __u32 dcd;
93 __u32 rx;
94 __u32 tx;
95 __u32 frame;
96 __u32 overrun;
97 __u32 parity;
98 __u32 brk;
99 __u32 buf_overrun;
100 };
101
102 typedef unsigned int __bitwise upf_t;
103 typedef unsigned int __bitwise upstat_t;
104
105 struct uart_port {
106 spinlock_t lock; /* port lock */
107 unsigned long iobase; /* in/out[bwl] */
108 unsigned char __iomem *membase; /* read/write[bwl] */
109 unsigned int (*serial_in)(struct uart_port *, int);
110 void (*serial_out)(struct uart_port *, int, int);
111 void (*set_termios)(struct uart_port *,
112 struct ktermios *new,
113 struct ktermios *old);
114 void (*set_ldisc)(struct uart_port *,
115 struct ktermios *);
116 unsigned int (*get_mctrl)(struct uart_port *);
117 void (*set_mctrl)(struct uart_port *, unsigned int);
118 unsigned int (*get_divisor)(struct uart_port *,
119 unsigned int baud,
120 unsigned int *frac);
121 void (*set_divisor)(struct uart_port *,
122 unsigned int baud,
123 unsigned int quot,
124 unsigned int quot_frac);
125 int (*startup)(struct uart_port *port);
126 void (*shutdown)(struct uart_port *port);
127 void (*throttle)(struct uart_port *port);
128 void (*unthrottle)(struct uart_port *port);
129 int (*handle_irq)(struct uart_port *);
130 void (*pm)(struct uart_port *, unsigned int state,
131 unsigned int old);
132 void (*handle_break)(struct uart_port *);
133 int (*rs485_config)(struct uart_port *,
134 struct serial_rs485 *rs485);
135 int (*iso7816_config)(struct uart_port *,
136 struct serial_iso7816 *iso7816);
137 unsigned int irq; /* irq number */
138 unsigned long irqflags; /* irq flags */
139 unsigned int uartclk; /* base uart clock */
140 unsigned int fifosize; /* tx fifo size */
141 unsigned char x_char; /* xon/xoff char */
142 unsigned char regshift; /* reg offset shift */
143 unsigned char iotype; /* io access style */
144 unsigned char quirks; /* internal quirks */
145
146 #define UPIO_PORT (SERIAL_IO_PORT) /* 8b I/O port access */
147 #define UPIO_HUB6 (SERIAL_IO_HUB6) /* Hub6 ISA card */
148 #define UPIO_MEM (SERIAL_IO_MEM) /* driver-specific */
149 #define UPIO_MEM32 (SERIAL_IO_MEM32) /* 32b little endian */
150 #define UPIO_AU (SERIAL_IO_AU) /* Au1x00 and RT288x type IO */
151 #define UPIO_TSI (SERIAL_IO_TSI) /* Tsi108/109 type IO */
152 #define UPIO_MEM32BE (SERIAL_IO_MEM32BE) /* 32b big endian */
153 #define UPIO_MEM16 (SERIAL_IO_MEM16) /* 16b little endian */
154
155 /* quirks must be updated while holding port mutex */
156 #define UPQ_NO_TXEN_TEST BIT(0)
157
158 unsigned int read_status_mask; /* driver specific */
159 unsigned int ignore_status_mask; /* driver specific */
160 struct uart_state *state; /* pointer to parent state */
161 struct uart_icount icount; /* statistics */
162
163 struct console *cons; /* struct console, if any */
164 #if defined(CONFIG_SERIAL_CORE_CONSOLE) || defined(SUPPORT_SYSRQ)
165 unsigned long sysrq; /* sysrq timeout */
166 unsigned int sysrq_ch; /* char for sysrq */
167 #endif
168
169 /* flags must be updated while holding port mutex */
170 upf_t flags;
171
172 /*
173 * These flags must be equivalent to the flags defined in
174 * include/uapi/linux/tty_flags.h which are the userspace definitions
175 * assigned from the serial_struct flags in uart_set_info()
176 * [for bit definitions in the UPF_CHANGE_MASK]
177 *
178 * Bits [0..UPF_LAST_USER] are userspace defined/visible/changeable
179 * The remaining bits are serial-core specific and not modifiable by
180 * userspace.
181 */
182 #define UPF_FOURPORT ((__force upf_t) ASYNC_FOURPORT /* 1 */ )
183 #define UPF_SAK ((__force upf_t) ASYNC_SAK /* 2 */ )
184 #define UPF_SPD_HI ((__force upf_t) ASYNC_SPD_HI /* 4 */ )
185 #define UPF_SPD_VHI ((__force upf_t) ASYNC_SPD_VHI /* 5 */ )
186 #define UPF_SPD_CUST ((__force upf_t) ASYNC_SPD_CUST /* 0x0030 */ )
187 #define UPF_SPD_WARP ((__force upf_t) ASYNC_SPD_WARP /* 0x1010 */ )
188 #define UPF_SPD_MASK ((__force upf_t) ASYNC_SPD_MASK /* 0x1030 */ )
189 #define UPF_SKIP_TEST ((__force upf_t) ASYNC_SKIP_TEST /* 6 */ )
190 #define UPF_AUTO_IRQ ((__force upf_t) ASYNC_AUTO_IRQ /* 7 */ )
191 #define UPF_HARDPPS_CD ((__force upf_t) ASYNC_HARDPPS_CD /* 11 */ )
192 #define UPF_SPD_SHI ((__force upf_t) ASYNC_SPD_SHI /* 12 */ )
193 #define UPF_LOW_LATENCY ((__force upf_t) ASYNC_LOW_LATENCY /* 13 */ )
194 #define UPF_BUGGY_UART ((__force upf_t) ASYNC_BUGGY_UART /* 14 */ )
195 #define UPF_MAGIC_MULTIPLIER ((__force upf_t) ASYNC_MAGIC_MULTIPLIER /* 16 */ )
196
197 #define UPF_NO_THRE_TEST ((__force upf_t) (1 << 19))
198 /* Port has hardware-assisted h/w flow control */
199 #define UPF_AUTO_CTS ((__force upf_t) (1 << 20))
200 #define UPF_AUTO_RTS ((__force upf_t) (1 << 21))
201 #define UPF_HARD_FLOW ((__force upf_t) (UPF_AUTO_CTS | UPF_AUTO_RTS))
202 /* Port has hardware-assisted s/w flow control */
203 #define UPF_SOFT_FLOW ((__force upf_t) (1 << 22))
204 #define UPF_CONS_FLOW ((__force upf_t) (1 << 23))
205 #define UPF_SHARE_IRQ ((__force upf_t) (1 << 24))
206 #define UPF_EXAR_EFR ((__force upf_t) (1 << 25))
207 #define UPF_BUG_THRE ((__force upf_t) (1 << 26))
208 /* The exact UART type is known and should not be probed. */
209 #define UPF_FIXED_TYPE ((__force upf_t) (1 << 27))
210 #define UPF_BOOT_AUTOCONF ((__force upf_t) (1 << 28))
211 #define UPF_FIXED_PORT ((__force upf_t) (1 << 29))
212 #define UPF_DEAD ((__force upf_t) (1 << 30))
213 #define UPF_IOREMAP ((__force upf_t) (1 << 31))
214
215 #define __UPF_CHANGE_MASK 0x17fff
216 #define UPF_CHANGE_MASK ((__force upf_t) __UPF_CHANGE_MASK)
217 #define UPF_USR_MASK ((__force upf_t) (UPF_SPD_MASK|UPF_LOW_LATENCY))
218
219 #if __UPF_CHANGE_MASK > ASYNC_FLAGS
220 #error Change mask not equivalent to userspace-visible bit defines
221 #endif
222
223 /*
224 * Must hold termios_rwsem, port mutex and port lock to change;
225 * can hold any one lock to read.
226 */
227 upstat_t status;
228
229 #define UPSTAT_CTS_ENABLE ((__force upstat_t) (1 << 0))
230 #define UPSTAT_DCD_ENABLE ((__force upstat_t) (1 << 1))
231 #define UPSTAT_AUTORTS ((__force upstat_t) (1 << 2))
232 #define UPSTAT_AUTOCTS ((__force upstat_t) (1 << 3))
233 #define UPSTAT_AUTOXOFF ((__force upstat_t) (1 << 4))
234 #define UPSTAT_SYNC_FIFO ((__force upstat_t) (1 << 5))
235
236 int hw_stopped; /* sw-assisted CTS flow state */
237 unsigned int mctrl; /* current modem ctrl settings */
238 unsigned int timeout; /* character-based timeout */
239 unsigned int type; /* port type */
240 const struct uart_ops *ops;
241 unsigned int custom_divisor;
242 unsigned int line; /* port index */
243 unsigned int minor;
244 resource_size_t mapbase; /* for ioremap */
245 resource_size_t mapsize;
246 struct device *dev; /* parent device */
247 unsigned char hub6; /* this should be in the 8250 driver */
248 unsigned char suspended;
249 unsigned char unused[2];
250 const char *name; /* port name */
251 struct attribute_group *attr_group; /* port specific attributes */
252 const struct attribute_group **tty_groups; /* all attributes (serial core use only) */
253 struct serial_rs485 rs485;
254 struct serial_iso7816 iso7816;
255 void *private_data; /* generic platform data pointer */
256 };
257
serial_port_in(struct uart_port * up,int offset)258 static inline int serial_port_in(struct uart_port *up, int offset)
259 {
260 return up->serial_in(up, offset);
261 }
262
serial_port_out(struct uart_port * up,int offset,int value)263 static inline void serial_port_out(struct uart_port *up, int offset, int value)
264 {
265 up->serial_out(up, offset, value);
266 }
267
268 /**
269 * enum uart_pm_state - power states for UARTs
270 * @UART_PM_STATE_ON: UART is powered, up and operational
271 * @UART_PM_STATE_OFF: UART is powered off
272 * @UART_PM_STATE_UNDEFINED: sentinel
273 */
274 enum uart_pm_state {
275 UART_PM_STATE_ON = 0,
276 UART_PM_STATE_OFF = 3, /* number taken from ACPI */
277 UART_PM_STATE_UNDEFINED,
278 };
279
280 /*
281 * This is the state information which is persistent across opens.
282 */
283 struct uart_state {
284 struct tty_port port;
285
286 enum uart_pm_state pm_state;
287 struct circ_buf xmit;
288
289 atomic_t refcount;
290 wait_queue_head_t remove_wait;
291 struct uart_port *uart_port;
292 };
293
294 #define UART_XMIT_SIZE PAGE_SIZE
295
296
297 /* number of characters left in xmit buffer before we ask for more */
298 #define WAKEUP_CHARS 256
299
300 struct module;
301 struct tty_driver;
302
303 struct uart_driver {
304 struct module *owner;
305 const char *driver_name;
306 const char *dev_name;
307 int major;
308 int minor;
309 int nr;
310 struct console *cons;
311
312 /*
313 * these are private; the low level driver should not
314 * touch these; they should be initialised to NULL
315 */
316 struct uart_state *state;
317 struct tty_driver *tty_driver;
318 };
319
320 void uart_write_wakeup(struct uart_port *port);
321
322 /*
323 * Baud rate helpers.
324 */
325 void uart_update_timeout(struct uart_port *port, unsigned int cflag,
326 unsigned int baud);
327 unsigned int uart_get_baud_rate(struct uart_port *port, struct ktermios *termios,
328 struct ktermios *old, unsigned int min,
329 unsigned int max);
330 unsigned int uart_get_divisor(struct uart_port *port, unsigned int baud);
331
332 /* Base timer interval for polling */
uart_poll_timeout(struct uart_port * port)333 static inline int uart_poll_timeout(struct uart_port *port)
334 {
335 int timeout = port->timeout;
336
337 return timeout > 6 ? (timeout / 2 - 2) : 1;
338 }
339
340 /*
341 * Console helpers.
342 */
343 struct earlycon_device {
344 struct console *con;
345 struct uart_port port;
346 char options[16]; /* e.g., 115200n8 */
347 unsigned int baud;
348 };
349
350 struct earlycon_id {
351 char name[15];
352 char name_term; /* In case compiler didn't '\0' term name */
353 char compatible[128];
354 int (*setup)(struct earlycon_device *, const char *options);
355 };
356
357 extern const struct earlycon_id *__earlycon_table[];
358 extern const struct earlycon_id *__earlycon_table_end[];
359
360 #if defined(CONFIG_SERIAL_EARLYCON) && !defined(MODULE)
361 #define EARLYCON_USED_OR_UNUSED __used
362 #else
363 #define EARLYCON_USED_OR_UNUSED __maybe_unused
364 #endif
365
366 #define _OF_EARLYCON_DECLARE(_name, compat, fn, unique_id) \
367 static const struct earlycon_id unique_id \
368 EARLYCON_USED_OR_UNUSED __initconst \
369 = { .name = __stringify(_name), \
370 .compatible = compat, \
371 .setup = fn }; \
372 static const struct earlycon_id EARLYCON_USED_OR_UNUSED \
373 __section(__earlycon_table) \
374 * const __PASTE(__p, unique_id) = &unique_id
375
376 #define OF_EARLYCON_DECLARE(_name, compat, fn) \
377 _OF_EARLYCON_DECLARE(_name, compat, fn, \
378 __UNIQUE_ID(__earlycon_##_name))
379
380 #define EARLYCON_DECLARE(_name, fn) OF_EARLYCON_DECLARE(_name, "", fn)
381
382 extern int of_setup_earlycon(const struct earlycon_id *match,
383 unsigned long node,
384 const char *options);
385
386 #ifdef CONFIG_SERIAL_EARLYCON
387 extern bool earlycon_acpi_spcr_enable __initdata;
388 int setup_earlycon(char *buf);
389 #else
390 static const bool earlycon_acpi_spcr_enable EARLYCON_USED_OR_UNUSED;
setup_earlycon(char * buf)391 static inline int setup_earlycon(char *buf) { return 0; }
392 #endif
393
394 struct uart_port *uart_get_console(struct uart_port *ports, int nr,
395 struct console *c);
396 int uart_parse_earlycon(char *p, unsigned char *iotype, resource_size_t *addr,
397 char **options);
398 void uart_parse_options(const char *options, int *baud, int *parity, int *bits,
399 int *flow);
400 int uart_set_options(struct uart_port *port, struct console *co, int baud,
401 int parity, int bits, int flow);
402 struct tty_driver *uart_console_device(struct console *co, int *index);
403 void uart_console_write(struct uart_port *port, const char *s,
404 unsigned int count,
405 void (*putchar)(struct uart_port *, int));
406
407 /*
408 * Port/driver registration/removal
409 */
410 int uart_register_driver(struct uart_driver *uart);
411 void uart_unregister_driver(struct uart_driver *uart);
412 int uart_add_one_port(struct uart_driver *reg, struct uart_port *port);
413 int uart_remove_one_port(struct uart_driver *reg, struct uart_port *port);
414 int uart_match_port(struct uart_port *port1, struct uart_port *port2);
415
416 /*
417 * Power Management
418 */
419 int uart_suspend_port(struct uart_driver *reg, struct uart_port *port);
420 int uart_resume_port(struct uart_driver *reg, struct uart_port *port);
421
422 #define uart_circ_empty(circ) ((circ)->head == (circ)->tail)
423 #define uart_circ_clear(circ) ((circ)->head = (circ)->tail = 0)
424
425 #define uart_circ_chars_pending(circ) \
426 (CIRC_CNT((circ)->head, (circ)->tail, UART_XMIT_SIZE))
427
428 #define uart_circ_chars_free(circ) \
429 (CIRC_SPACE((circ)->head, (circ)->tail, UART_XMIT_SIZE))
430
uart_tx_stopped(struct uart_port * port)431 static inline int uart_tx_stopped(struct uart_port *port)
432 {
433 struct tty_struct *tty = port->state->port.tty;
434 if ((tty && tty->stopped) || port->hw_stopped)
435 return 1;
436 return 0;
437 }
438
uart_cts_enabled(struct uart_port * uport)439 static inline bool uart_cts_enabled(struct uart_port *uport)
440 {
441 return !!(uport->status & UPSTAT_CTS_ENABLE);
442 }
443
uart_softcts_mode(struct uart_port * uport)444 static inline bool uart_softcts_mode(struct uart_port *uport)
445 {
446 upstat_t mask = UPSTAT_CTS_ENABLE | UPSTAT_AUTOCTS;
447
448 return ((uport->status & mask) == UPSTAT_CTS_ENABLE);
449 }
450
451 /*
452 * The following are helper functions for the low level drivers.
453 */
454
455 extern void uart_handle_dcd_change(struct uart_port *uport,
456 unsigned int status);
457 extern void uart_handle_cts_change(struct uart_port *uport,
458 unsigned int status);
459
460 extern void uart_insert_char(struct uart_port *port, unsigned int status,
461 unsigned int overrun, unsigned int ch, unsigned int flag);
462
463 #if defined(SUPPORT_SYSRQ) && defined(CONFIG_MAGIC_SYSRQ_SERIAL)
464 static inline int
uart_handle_sysrq_char(struct uart_port * port,unsigned int ch)465 uart_handle_sysrq_char(struct uart_port *port, unsigned int ch)
466 {
467 if (port->sysrq) {
468 if (ch && time_before(jiffies, port->sysrq)) {
469 handle_sysrq(ch);
470 port->sysrq = 0;
471 return 1;
472 }
473 port->sysrq = 0;
474 }
475 return 0;
476 }
477 static inline int
uart_prepare_sysrq_char(struct uart_port * port,unsigned int ch)478 uart_prepare_sysrq_char(struct uart_port *port, unsigned int ch)
479 {
480 if (port->sysrq) {
481 if (ch && time_before(jiffies, port->sysrq)) {
482 port->sysrq_ch = ch;
483 port->sysrq = 0;
484 return 1;
485 }
486 port->sysrq = 0;
487 }
488 return 0;
489 }
490 static inline void
uart_unlock_and_check_sysrq(struct uart_port * port,unsigned long irqflags)491 uart_unlock_and_check_sysrq(struct uart_port *port, unsigned long irqflags)
492 {
493 int sysrq_ch;
494
495 sysrq_ch = port->sysrq_ch;
496 port->sysrq_ch = 0;
497
498 spin_unlock_irqrestore(&port->lock, irqflags);
499
500 if (sysrq_ch)
501 handle_sysrq(sysrq_ch);
502 }
503 #else
504 static inline int
uart_handle_sysrq_char(struct uart_port * port,unsigned int ch)505 uart_handle_sysrq_char(struct uart_port *port, unsigned int ch) { return 0; }
506 static inline int
uart_prepare_sysrq_char(struct uart_port * port,unsigned int ch)507 uart_prepare_sysrq_char(struct uart_port *port, unsigned int ch) { return 0; }
508 static inline void
uart_unlock_and_check_sysrq(struct uart_port * port,unsigned long irqflags)509 uart_unlock_and_check_sysrq(struct uart_port *port, unsigned long irqflags)
510 {
511 spin_unlock_irqrestore(&port->lock, irqflags);
512 }
513 #endif
514
515 /*
516 * We do the SysRQ and SAK checking like this...
517 */
uart_handle_break(struct uart_port * port)518 static inline int uart_handle_break(struct uart_port *port)
519 {
520 struct uart_state *state = port->state;
521
522 if (port->handle_break)
523 port->handle_break(port);
524
525 #ifdef SUPPORT_SYSRQ
526 if (port->cons && port->cons->index == port->line) {
527 if (!port->sysrq) {
528 port->sysrq = jiffies + HZ*5;
529 return 1;
530 }
531 port->sysrq = 0;
532 }
533 #endif
534 if (port->flags & UPF_SAK)
535 do_SAK(state->port.tty);
536 return 0;
537 }
538
539 /*
540 * UART_ENABLE_MS - determine if port should enable modem status irqs
541 */
542 #define UART_ENABLE_MS(port,cflag) ((port)->flags & UPF_HARDPPS_CD || \
543 (cflag) & CRTSCTS || \
544 !((cflag) & CLOCAL))
545
546 void uart_get_rs485_mode(struct device *dev, struct serial_rs485 *rs485conf);
547 #endif /* LINUX_SERIAL_CORE_H */
548
