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 (*start_rx)(struct uart_port *);
49 void (*enable_ms)(struct uart_port *);
50 void (*break_ctl)(struct uart_port *, int ctl);
51 int (*startup)(struct uart_port *);
52 void (*shutdown)(struct uart_port *);
53 void (*flush_buffer)(struct uart_port *);
54 void (*set_termios)(struct uart_port *, struct ktermios *new,
55 struct ktermios *old);
56 void (*set_ldisc)(struct uart_port *, struct ktermios *);
57 void (*pm)(struct uart_port *, unsigned int state,
58 unsigned int oldstate);
59
60 /*
61 * Return a string describing the type of the port
62 */
63 const char *(*type)(struct uart_port *);
64
65 /*
66 * Release IO and memory resources used by the port.
67 * This includes iounmap if necessary.
68 */
69 void (*release_port)(struct uart_port *);
70
71 /*
72 * Request IO and memory resources used by the port.
73 * This includes iomapping the port if necessary.
74 */
75 int (*request_port)(struct uart_port *);
76 void (*config_port)(struct uart_port *, int);
77 int (*verify_port)(struct uart_port *, struct serial_struct *);
78 int (*ioctl)(struct uart_port *, unsigned int, unsigned long);
79 #ifdef CONFIG_CONSOLE_POLL
80 int (*poll_init)(struct uart_port *);
81 void (*poll_put_char)(struct uart_port *, unsigned char);
82 int (*poll_get_char)(struct uart_port *);
83 #endif
84 };
85
86 #define NO_POLL_CHAR 0x00ff0000
87 #define UART_CONFIG_TYPE (1 << 0)
88 #define UART_CONFIG_IRQ (1 << 1)
89
90 struct uart_icount {
91 __u32 cts;
92 __u32 dsr;
93 __u32 rng;
94 __u32 dcd;
95 __u32 rx;
96 __u32 tx;
97 __u32 frame;
98 __u32 overrun;
99 __u32 parity;
100 __u32 brk;
101 __u32 buf_overrun;
102 };
103
104 typedef unsigned int __bitwise upf_t;
105 typedef unsigned int __bitwise upstat_t;
106
107 struct uart_port {
108 spinlock_t lock; /* port lock */
109 unsigned long iobase; /* in/out[bwl] */
110 unsigned char __iomem *membase; /* read/write[bwl] */
111 unsigned int (*serial_in)(struct uart_port *, int);
112 void (*serial_out)(struct uart_port *, int, int);
113 void (*set_termios)(struct uart_port *,
114 struct ktermios *new,
115 struct ktermios *old);
116 void (*set_ldisc)(struct uart_port *,
117 struct ktermios *);
118 unsigned int (*get_mctrl)(struct uart_port *);
119 void (*set_mctrl)(struct uart_port *, unsigned int);
120 unsigned int (*get_divisor)(struct uart_port *,
121 unsigned int baud,
122 unsigned int *frac);
123 void (*set_divisor)(struct uart_port *,
124 unsigned int baud,
125 unsigned int quot,
126 unsigned int quot_frac);
127 int (*startup)(struct uart_port *port);
128 void (*shutdown)(struct uart_port *port);
129 void (*throttle)(struct uart_port *port);
130 void (*unthrottle)(struct uart_port *port);
131 int (*handle_irq)(struct uart_port *);
132 void (*pm)(struct uart_port *, unsigned int state,
133 unsigned int old);
134 void (*handle_break)(struct uart_port *);
135 int (*rs485_config)(struct uart_port *,
136 struct serial_rs485 *rs485);
137 int (*iso7816_config)(struct uart_port *,
138 struct serial_iso7816 *iso7816);
139 unsigned int irq; /* irq number */
140 unsigned long irqflags; /* irq flags */
141 unsigned int uartclk; /* base uart clock */
142 unsigned int fifosize; /* tx fifo size */
143 unsigned char x_char; /* xon/xoff char */
144 unsigned char regshift; /* reg offset shift */
145 unsigned char iotype; /* io access style */
146 unsigned char quirks; /* internal quirks */
147
148 #define UPIO_PORT (SERIAL_IO_PORT) /* 8b I/O port access */
149 #define UPIO_HUB6 (SERIAL_IO_HUB6) /* Hub6 ISA card */
150 #define UPIO_MEM (SERIAL_IO_MEM) /* driver-specific */
151 #define UPIO_MEM32 (SERIAL_IO_MEM32) /* 32b little endian */
152 #define UPIO_AU (SERIAL_IO_AU) /* Au1x00 and RT288x type IO */
153 #define UPIO_TSI (SERIAL_IO_TSI) /* Tsi108/109 type IO */
154 #define UPIO_MEM32BE (SERIAL_IO_MEM32BE) /* 32b big endian */
155 #define UPIO_MEM16 (SERIAL_IO_MEM16) /* 16b little endian */
156
157 /* quirks must be updated while holding port mutex */
158 #define UPQ_NO_TXEN_TEST BIT(0)
159
160 unsigned int read_status_mask; /* driver specific */
161 unsigned int ignore_status_mask; /* driver specific */
162 struct uart_state *state; /* pointer to parent state */
163 struct uart_icount icount; /* statistics */
164
165 struct console *cons; /* struct console, if any */
166 /* flags must be updated while holding port mutex */
167 upf_t flags;
168
169 /*
170 * These flags must be equivalent to the flags defined in
171 * include/uapi/linux/tty_flags.h which are the userspace definitions
172 * assigned from the serial_struct flags in uart_set_info()
173 * [for bit definitions in the UPF_CHANGE_MASK]
174 *
175 * Bits [0..ASYNCB_LAST_USER] are userspace defined/visible/changeable
176 * The remaining bits are serial-core specific and not modifiable by
177 * userspace.
178 */
179 #define UPF_FOURPORT ((__force upf_t) ASYNC_FOURPORT /* 1 */ )
180 #define UPF_SAK ((__force upf_t) ASYNC_SAK /* 2 */ )
181 #define UPF_SPD_HI ((__force upf_t) ASYNC_SPD_HI /* 4 */ )
182 #define UPF_SPD_VHI ((__force upf_t) ASYNC_SPD_VHI /* 5 */ )
183 #define UPF_SPD_CUST ((__force upf_t) ASYNC_SPD_CUST /* 0x0030 */ )
184 #define UPF_SPD_WARP ((__force upf_t) ASYNC_SPD_WARP /* 0x1010 */ )
185 #define UPF_SPD_MASK ((__force upf_t) ASYNC_SPD_MASK /* 0x1030 */ )
186 #define UPF_SKIP_TEST ((__force upf_t) ASYNC_SKIP_TEST /* 6 */ )
187 #define UPF_AUTO_IRQ ((__force upf_t) ASYNC_AUTO_IRQ /* 7 */ )
188 #define UPF_HARDPPS_CD ((__force upf_t) ASYNC_HARDPPS_CD /* 11 */ )
189 #define UPF_SPD_SHI ((__force upf_t) ASYNC_SPD_SHI /* 12 */ )
190 #define UPF_LOW_LATENCY ((__force upf_t) ASYNC_LOW_LATENCY /* 13 */ )
191 #define UPF_BUGGY_UART ((__force upf_t) ASYNC_BUGGY_UART /* 14 */ )
192 #define UPF_MAGIC_MULTIPLIER ((__force upf_t) ASYNC_MAGIC_MULTIPLIER /* 16 */ )
193
194 #define UPF_NO_THRE_TEST ((__force upf_t) (1 << 19))
195 /* Port has hardware-assisted h/w flow control */
196 #define UPF_AUTO_CTS ((__force upf_t) (1 << 20))
197 #define UPF_AUTO_RTS ((__force upf_t) (1 << 21))
198 #define UPF_HARD_FLOW ((__force upf_t) (UPF_AUTO_CTS | UPF_AUTO_RTS))
199 /* Port has hardware-assisted s/w flow control */
200 #define UPF_SOFT_FLOW ((__force upf_t) (1 << 22))
201 #define UPF_CONS_FLOW ((__force upf_t) (1 << 23))
202 #define UPF_SHARE_IRQ ((__force upf_t) (1 << 24))
203 #define UPF_EXAR_EFR ((__force upf_t) (1 << 25))
204 #define UPF_BUG_THRE ((__force upf_t) (1 << 26))
205 /* The exact UART type is known and should not be probed. */
206 #define UPF_FIXED_TYPE ((__force upf_t) (1 << 27))
207 #define UPF_BOOT_AUTOCONF ((__force upf_t) (1 << 28))
208 #define UPF_FIXED_PORT ((__force upf_t) (1 << 29))
209 #define UPF_DEAD ((__force upf_t) (1 << 30))
210 #define UPF_IOREMAP ((__force upf_t) (1 << 31))
211
212 #define __UPF_CHANGE_MASK 0x17fff
213 #define UPF_CHANGE_MASK ((__force upf_t) __UPF_CHANGE_MASK)
214 #define UPF_USR_MASK ((__force upf_t) (UPF_SPD_MASK|UPF_LOW_LATENCY))
215
216 #if __UPF_CHANGE_MASK > ASYNC_FLAGS
217 #error Change mask not equivalent to userspace-visible bit defines
218 #endif
219
220 /*
221 * Must hold termios_rwsem, port mutex and port lock to change;
222 * can hold any one lock to read.
223 */
224 upstat_t status;
225
226 #define UPSTAT_CTS_ENABLE ((__force upstat_t) (1 << 0))
227 #define UPSTAT_DCD_ENABLE ((__force upstat_t) (1 << 1))
228 #define UPSTAT_AUTORTS ((__force upstat_t) (1 << 2))
229 #define UPSTAT_AUTOCTS ((__force upstat_t) (1 << 3))
230 #define UPSTAT_AUTOXOFF ((__force upstat_t) (1 << 4))
231 #define UPSTAT_SYNC_FIFO ((__force upstat_t) (1 << 5))
232
233 int hw_stopped; /* sw-assisted CTS flow state */
234 unsigned int mctrl; /* current modem ctrl settings */
235 unsigned int timeout; /* character-based timeout */
236 unsigned int frame_time; /* frame timing in ns */
237 unsigned int type; /* port type */
238 const struct uart_ops *ops;
239 unsigned int custom_divisor;
240 unsigned int line; /* port index */
241 unsigned int minor;
242 resource_size_t mapbase; /* for ioremap */
243 resource_size_t mapsize;
244 struct device *dev; /* parent device */
245
246 unsigned long sysrq; /* sysrq timeout */
247 unsigned int sysrq_ch; /* char for sysrq */
248 unsigned char has_sysrq;
249 unsigned char sysrq_seq; /* index in sysrq_toggle_seq */
250
251 unsigned char hub6; /* this should be in the 8250 driver */
252 unsigned char suspended;
253 unsigned char console_reinit;
254 const char *name; /* port name */
255 struct attribute_group *attr_group; /* port specific attributes */
256 const struct attribute_group **tty_groups; /* all attributes (serial core use only) */
257 struct serial_rs485 rs485;
258 struct gpio_desc *rs485_term_gpio; /* enable RS485 bus termination */
259 struct serial_iso7816 iso7816;
260 void *private_data; /* generic platform data pointer */
261 };
262
serial_port_in(struct uart_port * up,int offset)263 static inline int serial_port_in(struct uart_port *up, int offset)
264 {
265 return up->serial_in(up, offset);
266 }
267
serial_port_out(struct uart_port * up,int offset,int value)268 static inline void serial_port_out(struct uart_port *up, int offset, int value)
269 {
270 up->serial_out(up, offset, value);
271 }
272
273 /**
274 * enum uart_pm_state - power states for UARTs
275 * @UART_PM_STATE_ON: UART is powered, up and operational
276 * @UART_PM_STATE_OFF: UART is powered off
277 * @UART_PM_STATE_UNDEFINED: sentinel
278 */
279 enum uart_pm_state {
280 UART_PM_STATE_ON = 0,
281 UART_PM_STATE_OFF = 3, /* number taken from ACPI */
282 UART_PM_STATE_UNDEFINED,
283 };
284
285 /*
286 * This is the state information which is persistent across opens.
287 */
288 struct uart_state {
289 struct tty_port port;
290
291 enum uart_pm_state pm_state;
292 struct circ_buf xmit;
293
294 atomic_t refcount;
295 wait_queue_head_t remove_wait;
296 struct uart_port *uart_port;
297 };
298
299 #define UART_XMIT_SIZE PAGE_SIZE
300
301
302 /* number of characters left in xmit buffer before we ask for more */
303 #define WAKEUP_CHARS 256
304
305 struct module;
306 struct tty_driver;
307
308 struct uart_driver {
309 struct module *owner;
310 const char *driver_name;
311 const char *dev_name;
312 int major;
313 int minor;
314 int nr;
315 struct console *cons;
316
317 /*
318 * these are private; the low level driver should not
319 * touch these; they should be initialised to NULL
320 */
321 struct uart_state *state;
322 struct tty_driver *tty_driver;
323 };
324
325 void uart_write_wakeup(struct uart_port *port);
326
327 /*
328 * Baud rate helpers.
329 */
330 void uart_update_timeout(struct uart_port *port, unsigned int cflag,
331 unsigned int baud);
332 unsigned int uart_get_baud_rate(struct uart_port *port, struct ktermios *termios,
333 struct ktermios *old, unsigned int min,
334 unsigned int max);
335 unsigned int uart_get_divisor(struct uart_port *port, unsigned int baud);
336
337 /* Base timer interval for polling */
uart_poll_timeout(struct uart_port * port)338 static inline int uart_poll_timeout(struct uart_port *port)
339 {
340 int timeout = port->timeout;
341
342 return timeout > 6 ? (timeout / 2 - 2) : 1;
343 }
344
345 /*
346 * Console helpers.
347 */
348 struct earlycon_device {
349 struct console *con;
350 struct uart_port port;
351 char options[16]; /* e.g., 115200n8 */
352 unsigned int baud;
353 };
354
355 struct earlycon_id {
356 char name[15];
357 char name_term; /* In case compiler didn't '\0' term name */
358 char compatible[128];
359 int (*setup)(struct earlycon_device *, const char *options);
360 };
361
362 extern const struct earlycon_id __earlycon_table[];
363 extern const struct earlycon_id __earlycon_table_end[];
364
365 #if defined(CONFIG_SERIAL_EARLYCON) && !defined(MODULE)
366 #define EARLYCON_USED_OR_UNUSED __used
367 #else
368 #define EARLYCON_USED_OR_UNUSED __maybe_unused
369 #endif
370
371 #define OF_EARLYCON_DECLARE(_name, compat, fn) \
372 static const struct earlycon_id __UNIQUE_ID(__earlycon_##_name) \
373 EARLYCON_USED_OR_UNUSED __section("__earlycon_table") \
374 __aligned(__alignof__(struct earlycon_id)) \
375 = { .name = __stringify(_name), \
376 .compatible = compat, \
377 .setup = fn }
378
379 #define EARLYCON_DECLARE(_name, fn) OF_EARLYCON_DECLARE(_name, "", fn)
380
381 extern int of_setup_earlycon(const struct earlycon_id *match,
382 unsigned long node,
383 const char *options);
384
385 #ifdef CONFIG_SERIAL_EARLYCON
386 extern bool earlycon_acpi_spcr_enable __initdata;
387 int setup_earlycon(char *buf);
388 #else
389 static const bool earlycon_acpi_spcr_enable EARLYCON_USED_OR_UNUSED;
setup_earlycon(char * buf)390 static inline int setup_earlycon(char *buf) { return 0; }
391 #endif
392
uart_console_enabled(struct uart_port * port)393 static inline bool uart_console_enabled(struct uart_port *port)
394 {
395 return uart_console(port) && (port->cons->flags & CON_ENABLED);
396 }
397
398 struct uart_port *uart_get_console(struct uart_port *ports, int nr,
399 struct console *c);
400 int uart_parse_earlycon(char *p, unsigned char *iotype, resource_size_t *addr,
401 char **options);
402 void uart_parse_options(const char *options, int *baud, int *parity, int *bits,
403 int *flow);
404 int uart_set_options(struct uart_port *port, struct console *co, int baud,
405 int parity, int bits, int flow);
406 struct tty_driver *uart_console_device(struct console *co, int *index);
407 void uart_console_write(struct uart_port *port, const char *s,
408 unsigned int count,
409 void (*putchar)(struct uart_port *, unsigned char));
410
411 /*
412 * Port/driver registration/removal
413 */
414 int uart_register_driver(struct uart_driver *uart);
415 void uart_unregister_driver(struct uart_driver *uart);
416 int uart_add_one_port(struct uart_driver *reg, struct uart_port *port);
417 int uart_remove_one_port(struct uart_driver *reg, struct uart_port *port);
418 bool uart_match_port(const struct uart_port *port1,
419 const struct uart_port *port2);
420
421 /*
422 * Power Management
423 */
424 int uart_suspend_port(struct uart_driver *reg, struct uart_port *port);
425 int uart_resume_port(struct uart_driver *reg, struct uart_port *port);
426
427 #define uart_circ_empty(circ) ((circ)->head == (circ)->tail)
428 #define uart_circ_clear(circ) ((circ)->head = (circ)->tail = 0)
429
430 #define uart_circ_chars_pending(circ) \
431 (CIRC_CNT((circ)->head, (circ)->tail, UART_XMIT_SIZE))
432
433 #define uart_circ_chars_free(circ) \
434 (CIRC_SPACE((circ)->head, (circ)->tail, UART_XMIT_SIZE))
435
uart_tx_stopped(struct uart_port * port)436 static inline int uart_tx_stopped(struct uart_port *port)
437 {
438 struct tty_struct *tty = port->state->port.tty;
439 if ((tty && tty->flow.stopped) || port->hw_stopped)
440 return 1;
441 return 0;
442 }
443
uart_cts_enabled(struct uart_port * uport)444 static inline bool uart_cts_enabled(struct uart_port *uport)
445 {
446 return !!(uport->status & UPSTAT_CTS_ENABLE);
447 }
448
uart_softcts_mode(struct uart_port * uport)449 static inline bool uart_softcts_mode(struct uart_port *uport)
450 {
451 upstat_t mask = UPSTAT_CTS_ENABLE | UPSTAT_AUTOCTS;
452
453 return ((uport->status & mask) == UPSTAT_CTS_ENABLE);
454 }
455
456 /*
457 * The following are helper functions for the low level drivers.
458 */
459
460 extern void uart_handle_dcd_change(struct uart_port *uport,
461 unsigned int status);
462 extern void uart_handle_cts_change(struct uart_port *uport,
463 unsigned int status);
464
465 extern void uart_insert_char(struct uart_port *port, unsigned int status,
466 unsigned int overrun, unsigned int ch, unsigned int flag);
467
468 void uart_xchar_out(struct uart_port *uport, int offset);
469
470 #ifdef CONFIG_MAGIC_SYSRQ_SERIAL
471 #define SYSRQ_TIMEOUT (HZ * 5)
472
473 bool uart_try_toggle_sysrq(struct uart_port *port, unsigned int ch);
474
uart_handle_sysrq_char(struct uart_port * port,unsigned int ch)475 static inline int uart_handle_sysrq_char(struct uart_port *port, unsigned int ch)
476 {
477 if (!port->sysrq)
478 return 0;
479
480 if (ch && time_before(jiffies, port->sysrq)) {
481 if (sysrq_mask()) {
482 handle_sysrq(ch);
483 port->sysrq = 0;
484 return 1;
485 }
486 if (uart_try_toggle_sysrq(port, ch))
487 return 1;
488 }
489 port->sysrq = 0;
490
491 return 0;
492 }
493
uart_prepare_sysrq_char(struct uart_port * port,unsigned int ch)494 static inline int uart_prepare_sysrq_char(struct uart_port *port, unsigned int ch)
495 {
496 if (!port->sysrq)
497 return 0;
498
499 if (ch && time_before(jiffies, port->sysrq)) {
500 if (sysrq_mask()) {
501 port->sysrq_ch = ch;
502 port->sysrq = 0;
503 return 1;
504 }
505 if (uart_try_toggle_sysrq(port, ch))
506 return 1;
507 }
508 port->sysrq = 0;
509
510 return 0;
511 }
512
uart_unlock_and_check_sysrq(struct uart_port * port)513 static inline void uart_unlock_and_check_sysrq(struct uart_port *port)
514 {
515 int sysrq_ch;
516
517 if (!port->has_sysrq) {
518 spin_unlock(&port->lock);
519 return;
520 }
521
522 sysrq_ch = port->sysrq_ch;
523 port->sysrq_ch = 0;
524
525 spin_unlock(&port->lock);
526
527 if (sysrq_ch)
528 handle_sysrq(sysrq_ch);
529 }
530
uart_unlock_and_check_sysrq_irqrestore(struct uart_port * port,unsigned long flags)531 static inline void uart_unlock_and_check_sysrq_irqrestore(struct uart_port *port,
532 unsigned long flags)
533 {
534 int sysrq_ch;
535
536 if (!port->has_sysrq) {
537 spin_unlock_irqrestore(&port->lock, flags);
538 return;
539 }
540
541 sysrq_ch = port->sysrq_ch;
542 port->sysrq_ch = 0;
543
544 spin_unlock_irqrestore(&port->lock, flags);
545
546 if (sysrq_ch)
547 handle_sysrq(sysrq_ch);
548 }
549 #else /* CONFIG_MAGIC_SYSRQ_SERIAL */
uart_handle_sysrq_char(struct uart_port * port,unsigned int ch)550 static inline int uart_handle_sysrq_char(struct uart_port *port, unsigned int ch)
551 {
552 return 0;
553 }
uart_prepare_sysrq_char(struct uart_port * port,unsigned int ch)554 static inline int uart_prepare_sysrq_char(struct uart_port *port, unsigned int ch)
555 {
556 return 0;
557 }
uart_unlock_and_check_sysrq(struct uart_port * port)558 static inline void uart_unlock_and_check_sysrq(struct uart_port *port)
559 {
560 spin_unlock(&port->lock);
561 }
uart_unlock_and_check_sysrq_irqrestore(struct uart_port * port,unsigned long flags)562 static inline void uart_unlock_and_check_sysrq_irqrestore(struct uart_port *port,
563 unsigned long flags)
564 {
565 spin_unlock_irqrestore(&port->lock, flags);
566 }
567 #endif /* CONFIG_MAGIC_SYSRQ_SERIAL */
568
569 /*
570 * We do the SysRQ and SAK checking like this...
571 */
uart_handle_break(struct uart_port * port)572 static inline int uart_handle_break(struct uart_port *port)
573 {
574 struct uart_state *state = port->state;
575
576 if (port->handle_break)
577 port->handle_break(port);
578
579 #ifdef CONFIG_MAGIC_SYSRQ_SERIAL
580 if (port->has_sysrq && uart_console(port)) {
581 if (!port->sysrq) {
582 port->sysrq = jiffies + SYSRQ_TIMEOUT;
583 return 1;
584 }
585 port->sysrq = 0;
586 }
587 #endif
588 if (port->flags & UPF_SAK)
589 do_SAK(state->port.tty);
590 return 0;
591 }
592
593 /*
594 * UART_ENABLE_MS - determine if port should enable modem status irqs
595 */
596 #define UART_ENABLE_MS(port,cflag) ((port)->flags & UPF_HARDPPS_CD || \
597 (cflag) & CRTSCTS || \
598 !((cflag) & CLOCAL))
599
600 int uart_get_rs485_mode(struct uart_port *port);
601 #endif /* LINUX_SERIAL_CORE_H */
602