1 // SPDX-License-Identifier: GPL-2.0+
2 /*
3 * Driver core for serial ports
4 *
5 * Based on drivers/char/serial.c, by Linus Torvalds, Theodore Ts'o.
6 *
7 * Copyright 1999 ARM Limited
8 * Copyright (C) 2000-2001 Deep Blue Solutions Ltd.
9 */
10 #include <linux/module.h>
11 #include <linux/tty.h>
12 #include <linux/tty_flip.h>
13 #include <linux/slab.h>
14 #include <linux/sched/signal.h>
15 #include <linux/init.h>
16 #include <linux/console.h>
17 #include <linux/gpio/consumer.h>
18 #include <linux/of.h>
19 #include <linux/proc_fs.h>
20 #include <linux/seq_file.h>
21 #include <linux/device.h>
22 #include <linux/serial.h> /* for serial_state and serial_icounter_struct */
23 #include <linux/serial_core.h>
24 #include <linux/sysrq.h>
25 #include <linux/delay.h>
26 #include <linux/mutex.h>
27 #include <linux/math64.h>
28 #include <linux/security.h>
29
30 #include <linux/irq.h>
31 #include <linux/uaccess.h>
32
33 /*
34 * This is used to lock changes in serial line configuration.
35 */
36 static DEFINE_MUTEX(port_mutex);
37
38 /*
39 * lockdep: port->lock is initialized in two places, but we
40 * want only one lock-class:
41 */
42 static struct lock_class_key port_lock_key;
43
44 #define HIGH_BITS_OFFSET ((sizeof(long)-sizeof(int))*8)
45
46 /*
47 * Max time with active RTS before/after data is sent.
48 */
49 #define RS485_MAX_RTS_DELAY 100 /* msecs */
50
51 static void uart_change_speed(struct tty_struct *tty, struct uart_state *state,
52 const struct ktermios *old_termios);
53 static void uart_wait_until_sent(struct tty_struct *tty, int timeout);
54 static void uart_change_pm(struct uart_state *state,
55 enum uart_pm_state pm_state);
56
57 static void uart_port_shutdown(struct tty_port *port);
58
uart_dcd_enabled(struct uart_port * uport)59 static int uart_dcd_enabled(struct uart_port *uport)
60 {
61 return !!(uport->status & UPSTAT_DCD_ENABLE);
62 }
63
uart_port_ref(struct uart_state * state)64 static inline struct uart_port *uart_port_ref(struct uart_state *state)
65 {
66 if (atomic_add_unless(&state->refcount, 1, 0))
67 return state->uart_port;
68 return NULL;
69 }
70
uart_port_deref(struct uart_port * uport)71 static inline void uart_port_deref(struct uart_port *uport)
72 {
73 if (atomic_dec_and_test(&uport->state->refcount))
74 wake_up(&uport->state->remove_wait);
75 }
76
77 #define uart_port_lock(state, flags) \
78 ({ \
79 struct uart_port *__uport = uart_port_ref(state); \
80 if (__uport) \
81 spin_lock_irqsave(&__uport->lock, flags); \
82 __uport; \
83 })
84
85 #define uart_port_unlock(uport, flags) \
86 ({ \
87 struct uart_port *__uport = uport; \
88 if (__uport) { \
89 spin_unlock_irqrestore(&__uport->lock, flags); \
90 uart_port_deref(__uport); \
91 } \
92 })
93
uart_port_check(struct uart_state * state)94 static inline struct uart_port *uart_port_check(struct uart_state *state)
95 {
96 lockdep_assert_held(&state->port.mutex);
97 return state->uart_port;
98 }
99
100 /**
101 * uart_write_wakeup - schedule write processing
102 * @port: port to be processed
103 *
104 * This routine is used by the interrupt handler to schedule processing in the
105 * software interrupt portion of the driver. A driver is expected to call this
106 * function when the number of characters in the transmit buffer have dropped
107 * below a threshold.
108 *
109 * Locking: @port->lock should be held
110 */
uart_write_wakeup(struct uart_port * port)111 void uart_write_wakeup(struct uart_port *port)
112 {
113 struct uart_state *state = port->state;
114 /*
115 * This means you called this function _after_ the port was
116 * closed. No cookie for you.
117 */
118 BUG_ON(!state);
119 tty_port_tty_wakeup(&state->port);
120 }
121 EXPORT_SYMBOL(uart_write_wakeup);
122
uart_stop(struct tty_struct * tty)123 static void uart_stop(struct tty_struct *tty)
124 {
125 struct uart_state *state = tty->driver_data;
126 struct uart_port *port;
127 unsigned long flags;
128
129 port = uart_port_lock(state, flags);
130 if (port)
131 port->ops->stop_tx(port);
132 uart_port_unlock(port, flags);
133 }
134
__uart_start(struct tty_struct * tty)135 static void __uart_start(struct tty_struct *tty)
136 {
137 struct uart_state *state = tty->driver_data;
138 struct uart_port *port = state->uart_port;
139
140 if (port && !uart_tx_stopped(port))
141 port->ops->start_tx(port);
142 }
143
uart_start(struct tty_struct * tty)144 static void uart_start(struct tty_struct *tty)
145 {
146 struct uart_state *state = tty->driver_data;
147 struct uart_port *port;
148 unsigned long flags;
149
150 port = uart_port_lock(state, flags);
151 __uart_start(tty);
152 uart_port_unlock(port, flags);
153 }
154
155 static void
uart_update_mctrl(struct uart_port * port,unsigned int set,unsigned int clear)156 uart_update_mctrl(struct uart_port *port, unsigned int set, unsigned int clear)
157 {
158 unsigned long flags;
159 unsigned int old;
160
161 spin_lock_irqsave(&port->lock, flags);
162 old = port->mctrl;
163 port->mctrl = (old & ~clear) | set;
164 if (old != port->mctrl && !(port->rs485.flags & SER_RS485_ENABLED))
165 port->ops->set_mctrl(port, port->mctrl);
166 spin_unlock_irqrestore(&port->lock, flags);
167 }
168
169 #define uart_set_mctrl(port, set) uart_update_mctrl(port, set, 0)
170 #define uart_clear_mctrl(port, clear) uart_update_mctrl(port, 0, clear)
171
uart_port_dtr_rts(struct uart_port * uport,int raise)172 static void uart_port_dtr_rts(struct uart_port *uport, int raise)
173 {
174 if (raise)
175 uart_set_mctrl(uport, TIOCM_DTR | TIOCM_RTS);
176 else
177 uart_clear_mctrl(uport, TIOCM_DTR | TIOCM_RTS);
178 }
179
180 /*
181 * Startup the port. This will be called once per open. All calls
182 * will be serialised by the per-port mutex.
183 */
uart_port_startup(struct tty_struct * tty,struct uart_state * state,int init_hw)184 static int uart_port_startup(struct tty_struct *tty, struct uart_state *state,
185 int init_hw)
186 {
187 struct uart_port *uport = uart_port_check(state);
188 unsigned long flags;
189 unsigned long page;
190 int retval = 0;
191
192 if (uport->type == PORT_UNKNOWN)
193 return 1;
194
195 /*
196 * Make sure the device is in D0 state.
197 */
198 uart_change_pm(state, UART_PM_STATE_ON);
199
200 /*
201 * Initialise and allocate the transmit and temporary
202 * buffer.
203 */
204 page = get_zeroed_page(GFP_KERNEL);
205 if (!page)
206 return -ENOMEM;
207
208 uart_port_lock(state, flags);
209 if (!state->xmit.buf) {
210 state->xmit.buf = (unsigned char *) page;
211 uart_circ_clear(&state->xmit);
212 uart_port_unlock(uport, flags);
213 } else {
214 uart_port_unlock(uport, flags);
215 /*
216 * Do not free() the page under the port lock, see
217 * uart_shutdown().
218 */
219 free_page(page);
220 }
221
222 retval = uport->ops->startup(uport);
223 if (retval == 0) {
224 if (uart_console(uport) && uport->cons->cflag) {
225 tty->termios.c_cflag = uport->cons->cflag;
226 tty->termios.c_ispeed = uport->cons->ispeed;
227 tty->termios.c_ospeed = uport->cons->ospeed;
228 uport->cons->cflag = 0;
229 uport->cons->ispeed = 0;
230 uport->cons->ospeed = 0;
231 }
232 /*
233 * Initialise the hardware port settings.
234 */
235 uart_change_speed(tty, state, NULL);
236
237 /*
238 * Setup the RTS and DTR signals once the
239 * port is open and ready to respond.
240 */
241 if (init_hw && C_BAUD(tty))
242 uart_port_dtr_rts(uport, 1);
243 }
244
245 /*
246 * This is to allow setserial on this port. People may want to set
247 * port/irq/type and then reconfigure the port properly if it failed
248 * now.
249 */
250 if (retval && capable(CAP_SYS_ADMIN))
251 return 1;
252
253 return retval;
254 }
255
uart_startup(struct tty_struct * tty,struct uart_state * state,int init_hw)256 static int uart_startup(struct tty_struct *tty, struct uart_state *state,
257 int init_hw)
258 {
259 struct tty_port *port = &state->port;
260 int retval;
261
262 if (tty_port_initialized(port))
263 return 0;
264
265 retval = uart_port_startup(tty, state, init_hw);
266 if (retval)
267 set_bit(TTY_IO_ERROR, &tty->flags);
268
269 return retval;
270 }
271
272 /*
273 * This routine will shutdown a serial port; interrupts are disabled, and
274 * DTR is dropped if the hangup on close termio flag is on. Calls to
275 * uart_shutdown are serialised by the per-port semaphore.
276 *
277 * uport == NULL if uart_port has already been removed
278 */
uart_shutdown(struct tty_struct * tty,struct uart_state * state)279 static void uart_shutdown(struct tty_struct *tty, struct uart_state *state)
280 {
281 struct uart_port *uport = uart_port_check(state);
282 struct tty_port *port = &state->port;
283 unsigned long flags;
284 char *xmit_buf = NULL;
285
286 /*
287 * Set the TTY IO error marker
288 */
289 if (tty)
290 set_bit(TTY_IO_ERROR, &tty->flags);
291
292 if (tty_port_initialized(port)) {
293 tty_port_set_initialized(port, 0);
294
295 /*
296 * Turn off DTR and RTS early.
297 */
298 if (uport && uart_console(uport) && tty) {
299 uport->cons->cflag = tty->termios.c_cflag;
300 uport->cons->ispeed = tty->termios.c_ispeed;
301 uport->cons->ospeed = tty->termios.c_ospeed;
302 }
303
304 if (!tty || C_HUPCL(tty))
305 uart_port_dtr_rts(uport, 0);
306
307 uart_port_shutdown(port);
308 }
309
310 /*
311 * It's possible for shutdown to be called after suspend if we get
312 * a DCD drop (hangup) at just the right time. Clear suspended bit so
313 * we don't try to resume a port that has been shutdown.
314 */
315 tty_port_set_suspended(port, 0);
316
317 /*
318 * Do not free() the transmit buffer page under the port lock since
319 * this can create various circular locking scenarios. For instance,
320 * console driver may need to allocate/free a debug object, which
321 * can endup in printk() recursion.
322 */
323 uart_port_lock(state, flags);
324 xmit_buf = state->xmit.buf;
325 state->xmit.buf = NULL;
326 uart_port_unlock(uport, flags);
327
328 free_page((unsigned long)xmit_buf);
329 }
330
331 /**
332 * uart_update_timeout - update per-port frame timing information
333 * @port: uart_port structure describing the port
334 * @cflag: termios cflag value
335 * @baud: speed of the port
336 *
337 * Set the @port frame timing information from which the FIFO timeout value is
338 * derived. The @cflag value should reflect the actual hardware settings as
339 * number of bits, parity, stop bits and baud rate is taken into account here.
340 *
341 * Locking: caller is expected to take @port->lock
342 */
343 void
uart_update_timeout(struct uart_port * port,unsigned int cflag,unsigned int baud)344 uart_update_timeout(struct uart_port *port, unsigned int cflag,
345 unsigned int baud)
346 {
347 unsigned int size = tty_get_frame_size(cflag);
348 u64 frame_time;
349
350 frame_time = (u64)size * NSEC_PER_SEC;
351 port->frame_time = DIV64_U64_ROUND_UP(frame_time, baud);
352 }
353 EXPORT_SYMBOL(uart_update_timeout);
354
355 /**
356 * uart_get_baud_rate - return baud rate for a particular port
357 * @port: uart_port structure describing the port in question.
358 * @termios: desired termios settings
359 * @old: old termios (or %NULL)
360 * @min: minimum acceptable baud rate
361 * @max: maximum acceptable baud rate
362 *
363 * Decode the termios structure into a numeric baud rate, taking account of the
364 * magic 38400 baud rate (with spd_* flags), and mapping the %B0 rate to 9600
365 * baud.
366 *
367 * If the new baud rate is invalid, try the @old termios setting. If it's still
368 * invalid, we try 9600 baud.
369 *
370 * The @termios structure is updated to reflect the baud rate we're actually
371 * going to be using. Don't do this for the case where B0 is requested ("hang
372 * up").
373 *
374 * Locking: caller dependent
375 */
376 unsigned int
uart_get_baud_rate(struct uart_port * port,struct ktermios * termios,const struct ktermios * old,unsigned int min,unsigned int max)377 uart_get_baud_rate(struct uart_port *port, struct ktermios *termios,
378 const struct ktermios *old, unsigned int min, unsigned int max)
379 {
380 unsigned int try;
381 unsigned int baud;
382 unsigned int altbaud;
383 int hung_up = 0;
384 upf_t flags = port->flags & UPF_SPD_MASK;
385
386 switch (flags) {
387 case UPF_SPD_HI:
388 altbaud = 57600;
389 break;
390 case UPF_SPD_VHI:
391 altbaud = 115200;
392 break;
393 case UPF_SPD_SHI:
394 altbaud = 230400;
395 break;
396 case UPF_SPD_WARP:
397 altbaud = 460800;
398 break;
399 default:
400 altbaud = 38400;
401 break;
402 }
403
404 for (try = 0; try < 2; try++) {
405 baud = tty_termios_baud_rate(termios);
406
407 /*
408 * The spd_hi, spd_vhi, spd_shi, spd_warp kludge...
409 * Die! Die! Die!
410 */
411 if (try == 0 && baud == 38400)
412 baud = altbaud;
413
414 /*
415 * Special case: B0 rate.
416 */
417 if (baud == 0) {
418 hung_up = 1;
419 baud = 9600;
420 }
421
422 if (baud >= min && baud <= max)
423 return baud;
424
425 /*
426 * Oops, the quotient was zero. Try again with
427 * the old baud rate if possible.
428 */
429 termios->c_cflag &= ~CBAUD;
430 if (old) {
431 baud = tty_termios_baud_rate(old);
432 if (!hung_up)
433 tty_termios_encode_baud_rate(termios,
434 baud, baud);
435 old = NULL;
436 continue;
437 }
438
439 /*
440 * As a last resort, if the range cannot be met then clip to
441 * the nearest chip supported rate.
442 */
443 if (!hung_up) {
444 if (baud <= min)
445 tty_termios_encode_baud_rate(termios,
446 min + 1, min + 1);
447 else
448 tty_termios_encode_baud_rate(termios,
449 max - 1, max - 1);
450 }
451 }
452 /* Should never happen */
453 WARN_ON(1);
454 return 0;
455 }
456 EXPORT_SYMBOL(uart_get_baud_rate);
457
458 /**
459 * uart_get_divisor - return uart clock divisor
460 * @port: uart_port structure describing the port
461 * @baud: desired baud rate
462 *
463 * Calculate the divisor (baud_base / baud) for the specified @baud,
464 * appropriately rounded.
465 *
466 * If 38400 baud and custom divisor is selected, return the custom divisor
467 * instead.
468 *
469 * Locking: caller dependent
470 */
471 unsigned int
uart_get_divisor(struct uart_port * port,unsigned int baud)472 uart_get_divisor(struct uart_port *port, unsigned int baud)
473 {
474 unsigned int quot;
475
476 /*
477 * Old custom speed handling.
478 */
479 if (baud == 38400 && (port->flags & UPF_SPD_MASK) == UPF_SPD_CUST)
480 quot = port->custom_divisor;
481 else
482 quot = DIV_ROUND_CLOSEST(port->uartclk, 16 * baud);
483
484 return quot;
485 }
486 EXPORT_SYMBOL(uart_get_divisor);
487
488 /* Caller holds port mutex */
uart_change_speed(struct tty_struct * tty,struct uart_state * state,const struct ktermios * old_termios)489 static void uart_change_speed(struct tty_struct *tty, struct uart_state *state,
490 const struct ktermios *old_termios)
491 {
492 struct uart_port *uport = uart_port_check(state);
493 struct ktermios *termios;
494 int hw_stopped;
495
496 /*
497 * If we have no tty, termios, or the port does not exist,
498 * then we can't set the parameters for this port.
499 */
500 if (!tty || uport->type == PORT_UNKNOWN)
501 return;
502
503 termios = &tty->termios;
504 uport->ops->set_termios(uport, termios, old_termios);
505
506 /*
507 * Set modem status enables based on termios cflag
508 */
509 spin_lock_irq(&uport->lock);
510 if (termios->c_cflag & CRTSCTS)
511 uport->status |= UPSTAT_CTS_ENABLE;
512 else
513 uport->status &= ~UPSTAT_CTS_ENABLE;
514
515 if (termios->c_cflag & CLOCAL)
516 uport->status &= ~UPSTAT_DCD_ENABLE;
517 else
518 uport->status |= UPSTAT_DCD_ENABLE;
519
520 /* reset sw-assisted CTS flow control based on (possibly) new mode */
521 hw_stopped = uport->hw_stopped;
522 uport->hw_stopped = uart_softcts_mode(uport) &&
523 !(uport->ops->get_mctrl(uport) & TIOCM_CTS);
524 if (uport->hw_stopped) {
525 if (!hw_stopped)
526 uport->ops->stop_tx(uport);
527 } else {
528 if (hw_stopped)
529 __uart_start(tty);
530 }
531 spin_unlock_irq(&uport->lock);
532 }
533
uart_put_char(struct tty_struct * tty,unsigned char c)534 static int uart_put_char(struct tty_struct *tty, unsigned char c)
535 {
536 struct uart_state *state = tty->driver_data;
537 struct uart_port *port;
538 struct circ_buf *circ;
539 unsigned long flags;
540 int ret = 0;
541
542 circ = &state->xmit;
543 port = uart_port_lock(state, flags);
544 if (!circ->buf) {
545 uart_port_unlock(port, flags);
546 return 0;
547 }
548
549 if (port && uart_circ_chars_free(circ) != 0) {
550 circ->buf[circ->head] = c;
551 circ->head = (circ->head + 1) & (UART_XMIT_SIZE - 1);
552 ret = 1;
553 }
554 uart_port_unlock(port, flags);
555 return ret;
556 }
557
uart_flush_chars(struct tty_struct * tty)558 static void uart_flush_chars(struct tty_struct *tty)
559 {
560 uart_start(tty);
561 }
562
uart_write(struct tty_struct * tty,const unsigned char * buf,int count)563 static int uart_write(struct tty_struct *tty,
564 const unsigned char *buf, int count)
565 {
566 struct uart_state *state = tty->driver_data;
567 struct uart_port *port;
568 struct circ_buf *circ;
569 unsigned long flags;
570 int c, ret = 0;
571
572 /*
573 * This means you called this function _after_ the port was
574 * closed. No cookie for you.
575 */
576 if (!state) {
577 WARN_ON(1);
578 return -EL3HLT;
579 }
580
581 port = uart_port_lock(state, flags);
582 circ = &state->xmit;
583 if (!circ->buf) {
584 uart_port_unlock(port, flags);
585 return 0;
586 }
587
588 while (port) {
589 c = CIRC_SPACE_TO_END(circ->head, circ->tail, UART_XMIT_SIZE);
590 if (count < c)
591 c = count;
592 if (c <= 0)
593 break;
594 memcpy(circ->buf + circ->head, buf, c);
595 circ->head = (circ->head + c) & (UART_XMIT_SIZE - 1);
596 buf += c;
597 count -= c;
598 ret += c;
599 }
600
601 __uart_start(tty);
602 uart_port_unlock(port, flags);
603 return ret;
604 }
605
uart_write_room(struct tty_struct * tty)606 static unsigned int uart_write_room(struct tty_struct *tty)
607 {
608 struct uart_state *state = tty->driver_data;
609 struct uart_port *port;
610 unsigned long flags;
611 unsigned int ret;
612
613 port = uart_port_lock(state, flags);
614 ret = uart_circ_chars_free(&state->xmit);
615 uart_port_unlock(port, flags);
616 return ret;
617 }
618
uart_chars_in_buffer(struct tty_struct * tty)619 static unsigned int uart_chars_in_buffer(struct tty_struct *tty)
620 {
621 struct uart_state *state = tty->driver_data;
622 struct uart_port *port;
623 unsigned long flags;
624 unsigned int ret;
625
626 port = uart_port_lock(state, flags);
627 ret = uart_circ_chars_pending(&state->xmit);
628 uart_port_unlock(port, flags);
629 return ret;
630 }
631
uart_flush_buffer(struct tty_struct * tty)632 static void uart_flush_buffer(struct tty_struct *tty)
633 {
634 struct uart_state *state = tty->driver_data;
635 struct uart_port *port;
636 unsigned long flags;
637
638 /*
639 * This means you called this function _after_ the port was
640 * closed. No cookie for you.
641 */
642 if (!state) {
643 WARN_ON(1);
644 return;
645 }
646
647 pr_debug("uart_flush_buffer(%d) called\n", tty->index);
648
649 port = uart_port_lock(state, flags);
650 if (!port)
651 return;
652 uart_circ_clear(&state->xmit);
653 if (port->ops->flush_buffer)
654 port->ops->flush_buffer(port);
655 uart_port_unlock(port, flags);
656 tty_port_tty_wakeup(&state->port);
657 }
658
659 /*
660 * This function performs low-level write of high-priority XON/XOFF
661 * character and accounting for it.
662 *
663 * Requires uart_port to implement .serial_out().
664 */
uart_xchar_out(struct uart_port * uport,int offset)665 void uart_xchar_out(struct uart_port *uport, int offset)
666 {
667 serial_port_out(uport, offset, uport->x_char);
668 uport->icount.tx++;
669 uport->x_char = 0;
670 }
671 EXPORT_SYMBOL_GPL(uart_xchar_out);
672
673 /*
674 * This function is used to send a high-priority XON/XOFF character to
675 * the device
676 */
uart_send_xchar(struct tty_struct * tty,char ch)677 static void uart_send_xchar(struct tty_struct *tty, char ch)
678 {
679 struct uart_state *state = tty->driver_data;
680 struct uart_port *port;
681 unsigned long flags;
682
683 port = uart_port_ref(state);
684 if (!port)
685 return;
686
687 if (port->ops->send_xchar)
688 port->ops->send_xchar(port, ch);
689 else {
690 spin_lock_irqsave(&port->lock, flags);
691 port->x_char = ch;
692 if (ch)
693 port->ops->start_tx(port);
694 spin_unlock_irqrestore(&port->lock, flags);
695 }
696 uart_port_deref(port);
697 }
698
uart_throttle(struct tty_struct * tty)699 static void uart_throttle(struct tty_struct *tty)
700 {
701 struct uart_state *state = tty->driver_data;
702 upstat_t mask = UPSTAT_SYNC_FIFO;
703 struct uart_port *port;
704
705 port = uart_port_ref(state);
706 if (!port)
707 return;
708
709 if (I_IXOFF(tty))
710 mask |= UPSTAT_AUTOXOFF;
711 if (C_CRTSCTS(tty))
712 mask |= UPSTAT_AUTORTS;
713
714 if (port->status & mask) {
715 port->ops->throttle(port);
716 mask &= ~port->status;
717 }
718
719 if (mask & UPSTAT_AUTORTS)
720 uart_clear_mctrl(port, TIOCM_RTS);
721
722 if (mask & UPSTAT_AUTOXOFF)
723 uart_send_xchar(tty, STOP_CHAR(tty));
724
725 uart_port_deref(port);
726 }
727
uart_unthrottle(struct tty_struct * tty)728 static void uart_unthrottle(struct tty_struct *tty)
729 {
730 struct uart_state *state = tty->driver_data;
731 upstat_t mask = UPSTAT_SYNC_FIFO;
732 struct uart_port *port;
733
734 port = uart_port_ref(state);
735 if (!port)
736 return;
737
738 if (I_IXOFF(tty))
739 mask |= UPSTAT_AUTOXOFF;
740 if (C_CRTSCTS(tty))
741 mask |= UPSTAT_AUTORTS;
742
743 if (port->status & mask) {
744 port->ops->unthrottle(port);
745 mask &= ~port->status;
746 }
747
748 if (mask & UPSTAT_AUTORTS)
749 uart_set_mctrl(port, TIOCM_RTS);
750
751 if (mask & UPSTAT_AUTOXOFF)
752 uart_send_xchar(tty, START_CHAR(tty));
753
754 uart_port_deref(port);
755 }
756
uart_get_info(struct tty_port * port,struct serial_struct * retinfo)757 static int uart_get_info(struct tty_port *port, struct serial_struct *retinfo)
758 {
759 struct uart_state *state = container_of(port, struct uart_state, port);
760 struct uart_port *uport;
761 int ret = -ENODEV;
762
763 /*
764 * Ensure the state we copy is consistent and no hardware changes
765 * occur as we go
766 */
767 mutex_lock(&port->mutex);
768 uport = uart_port_check(state);
769 if (!uport)
770 goto out;
771
772 retinfo->type = uport->type;
773 retinfo->line = uport->line;
774 retinfo->port = uport->iobase;
775 if (HIGH_BITS_OFFSET)
776 retinfo->port_high = (long) uport->iobase >> HIGH_BITS_OFFSET;
777 retinfo->irq = uport->irq;
778 retinfo->flags = (__force int)uport->flags;
779 retinfo->xmit_fifo_size = uport->fifosize;
780 retinfo->baud_base = uport->uartclk / 16;
781 retinfo->close_delay = jiffies_to_msecs(port->close_delay) / 10;
782 retinfo->closing_wait = port->closing_wait == ASYNC_CLOSING_WAIT_NONE ?
783 ASYNC_CLOSING_WAIT_NONE :
784 jiffies_to_msecs(port->closing_wait) / 10;
785 retinfo->custom_divisor = uport->custom_divisor;
786 retinfo->hub6 = uport->hub6;
787 retinfo->io_type = uport->iotype;
788 retinfo->iomem_reg_shift = uport->regshift;
789 retinfo->iomem_base = (void *)(unsigned long)uport->mapbase;
790
791 ret = 0;
792 out:
793 mutex_unlock(&port->mutex);
794 return ret;
795 }
796
uart_get_info_user(struct tty_struct * tty,struct serial_struct * ss)797 static int uart_get_info_user(struct tty_struct *tty,
798 struct serial_struct *ss)
799 {
800 struct uart_state *state = tty->driver_data;
801 struct tty_port *port = &state->port;
802
803 return uart_get_info(port, ss) < 0 ? -EIO : 0;
804 }
805
uart_set_info(struct tty_struct * tty,struct tty_port * port,struct uart_state * state,struct serial_struct * new_info)806 static int uart_set_info(struct tty_struct *tty, struct tty_port *port,
807 struct uart_state *state,
808 struct serial_struct *new_info)
809 {
810 struct uart_port *uport = uart_port_check(state);
811 unsigned long new_port;
812 unsigned int change_irq, change_port, closing_wait;
813 unsigned int old_custom_divisor, close_delay;
814 upf_t old_flags, new_flags;
815 int retval = 0;
816
817 if (!uport)
818 return -EIO;
819
820 new_port = new_info->port;
821 if (HIGH_BITS_OFFSET)
822 new_port += (unsigned long) new_info->port_high << HIGH_BITS_OFFSET;
823
824 new_info->irq = irq_canonicalize(new_info->irq);
825 close_delay = msecs_to_jiffies(new_info->close_delay * 10);
826 closing_wait = new_info->closing_wait == ASYNC_CLOSING_WAIT_NONE ?
827 ASYNC_CLOSING_WAIT_NONE :
828 msecs_to_jiffies(new_info->closing_wait * 10);
829
830
831 change_irq = !(uport->flags & UPF_FIXED_PORT)
832 && new_info->irq != uport->irq;
833
834 /*
835 * Since changing the 'type' of the port changes its resource
836 * allocations, we should treat type changes the same as
837 * IO port changes.
838 */
839 change_port = !(uport->flags & UPF_FIXED_PORT)
840 && (new_port != uport->iobase ||
841 (unsigned long)new_info->iomem_base != uport->mapbase ||
842 new_info->hub6 != uport->hub6 ||
843 new_info->io_type != uport->iotype ||
844 new_info->iomem_reg_shift != uport->regshift ||
845 new_info->type != uport->type);
846
847 old_flags = uport->flags;
848 new_flags = (__force upf_t)new_info->flags;
849 old_custom_divisor = uport->custom_divisor;
850
851 if (!capable(CAP_SYS_ADMIN)) {
852 retval = -EPERM;
853 if (change_irq || change_port ||
854 (new_info->baud_base != uport->uartclk / 16) ||
855 (close_delay != port->close_delay) ||
856 (closing_wait != port->closing_wait) ||
857 (new_info->xmit_fifo_size &&
858 new_info->xmit_fifo_size != uport->fifosize) ||
859 (((new_flags ^ old_flags) & ~UPF_USR_MASK) != 0))
860 goto exit;
861 uport->flags = ((uport->flags & ~UPF_USR_MASK) |
862 (new_flags & UPF_USR_MASK));
863 uport->custom_divisor = new_info->custom_divisor;
864 goto check_and_exit;
865 }
866
867 if (change_irq || change_port) {
868 retval = security_locked_down(LOCKDOWN_TIOCSSERIAL);
869 if (retval)
870 goto exit;
871 }
872
873 /*
874 * Ask the low level driver to verify the settings.
875 */
876 if (uport->ops->verify_port)
877 retval = uport->ops->verify_port(uport, new_info);
878
879 if ((new_info->irq >= nr_irqs) || (new_info->irq < 0) ||
880 (new_info->baud_base < 9600))
881 retval = -EINVAL;
882
883 if (retval)
884 goto exit;
885
886 if (change_port || change_irq) {
887 retval = -EBUSY;
888
889 /*
890 * Make sure that we are the sole user of this port.
891 */
892 if (tty_port_users(port) > 1)
893 goto exit;
894
895 /*
896 * We need to shutdown the serial port at the old
897 * port/type/irq combination.
898 */
899 uart_shutdown(tty, state);
900 }
901
902 if (change_port) {
903 unsigned long old_iobase, old_mapbase;
904 unsigned int old_type, old_iotype, old_hub6, old_shift;
905
906 old_iobase = uport->iobase;
907 old_mapbase = uport->mapbase;
908 old_type = uport->type;
909 old_hub6 = uport->hub6;
910 old_iotype = uport->iotype;
911 old_shift = uport->regshift;
912
913 /*
914 * Free and release old regions
915 */
916 if (old_type != PORT_UNKNOWN && uport->ops->release_port)
917 uport->ops->release_port(uport);
918
919 uport->iobase = new_port;
920 uport->type = new_info->type;
921 uport->hub6 = new_info->hub6;
922 uport->iotype = new_info->io_type;
923 uport->regshift = new_info->iomem_reg_shift;
924 uport->mapbase = (unsigned long)new_info->iomem_base;
925
926 /*
927 * Claim and map the new regions
928 */
929 if (uport->type != PORT_UNKNOWN && uport->ops->request_port) {
930 retval = uport->ops->request_port(uport);
931 } else {
932 /* Always success - Jean II */
933 retval = 0;
934 }
935
936 /*
937 * If we fail to request resources for the
938 * new port, try to restore the old settings.
939 */
940 if (retval) {
941 uport->iobase = old_iobase;
942 uport->type = old_type;
943 uport->hub6 = old_hub6;
944 uport->iotype = old_iotype;
945 uport->regshift = old_shift;
946 uport->mapbase = old_mapbase;
947
948 if (old_type != PORT_UNKNOWN) {
949 retval = uport->ops->request_port(uport);
950 /*
951 * If we failed to restore the old settings,
952 * we fail like this.
953 */
954 if (retval)
955 uport->type = PORT_UNKNOWN;
956
957 /*
958 * We failed anyway.
959 */
960 retval = -EBUSY;
961 }
962
963 /* Added to return the correct error -Ram Gupta */
964 goto exit;
965 }
966 }
967
968 if (change_irq)
969 uport->irq = new_info->irq;
970 if (!(uport->flags & UPF_FIXED_PORT))
971 uport->uartclk = new_info->baud_base * 16;
972 uport->flags = (uport->flags & ~UPF_CHANGE_MASK) |
973 (new_flags & UPF_CHANGE_MASK);
974 uport->custom_divisor = new_info->custom_divisor;
975 port->close_delay = close_delay;
976 port->closing_wait = closing_wait;
977 if (new_info->xmit_fifo_size)
978 uport->fifosize = new_info->xmit_fifo_size;
979
980 check_and_exit:
981 retval = 0;
982 if (uport->type == PORT_UNKNOWN)
983 goto exit;
984 if (tty_port_initialized(port)) {
985 if (((old_flags ^ uport->flags) & UPF_SPD_MASK) ||
986 old_custom_divisor != uport->custom_divisor) {
987 /*
988 * If they're setting up a custom divisor or speed,
989 * instead of clearing it, then bitch about it.
990 */
991 if (uport->flags & UPF_SPD_MASK) {
992 dev_notice_ratelimited(uport->dev,
993 "%s sets custom speed on %s. This is deprecated.\n",
994 current->comm,
995 tty_name(port->tty));
996 }
997 uart_change_speed(tty, state, NULL);
998 }
999 } else {
1000 retval = uart_startup(tty, state, 1);
1001 if (retval == 0)
1002 tty_port_set_initialized(port, true);
1003 if (retval > 0)
1004 retval = 0;
1005 }
1006 exit:
1007 return retval;
1008 }
1009
uart_set_info_user(struct tty_struct * tty,struct serial_struct * ss)1010 static int uart_set_info_user(struct tty_struct *tty, struct serial_struct *ss)
1011 {
1012 struct uart_state *state = tty->driver_data;
1013 struct tty_port *port = &state->port;
1014 int retval;
1015
1016 down_write(&tty->termios_rwsem);
1017 /*
1018 * This semaphore protects port->count. It is also
1019 * very useful to prevent opens. Also, take the
1020 * port configuration semaphore to make sure that a
1021 * module insertion/removal doesn't change anything
1022 * under us.
1023 */
1024 mutex_lock(&port->mutex);
1025 retval = uart_set_info(tty, port, state, ss);
1026 mutex_unlock(&port->mutex);
1027 up_write(&tty->termios_rwsem);
1028 return retval;
1029 }
1030
1031 /**
1032 * uart_get_lsr_info - get line status register info
1033 * @tty: tty associated with the UART
1034 * @state: UART being queried
1035 * @value: returned modem value
1036 */
uart_get_lsr_info(struct tty_struct * tty,struct uart_state * state,unsigned int __user * value)1037 static int uart_get_lsr_info(struct tty_struct *tty,
1038 struct uart_state *state, unsigned int __user *value)
1039 {
1040 struct uart_port *uport = uart_port_check(state);
1041 unsigned int result;
1042
1043 result = uport->ops->tx_empty(uport);
1044
1045 /*
1046 * If we're about to load something into the transmit
1047 * register, we'll pretend the transmitter isn't empty to
1048 * avoid a race condition (depending on when the transmit
1049 * interrupt happens).
1050 */
1051 if (uport->x_char ||
1052 ((uart_circ_chars_pending(&state->xmit) > 0) &&
1053 !uart_tx_stopped(uport)))
1054 result &= ~TIOCSER_TEMT;
1055
1056 return put_user(result, value);
1057 }
1058
uart_tiocmget(struct tty_struct * tty)1059 static int uart_tiocmget(struct tty_struct *tty)
1060 {
1061 struct uart_state *state = tty->driver_data;
1062 struct tty_port *port = &state->port;
1063 struct uart_port *uport;
1064 int result = -EIO;
1065
1066 mutex_lock(&port->mutex);
1067 uport = uart_port_check(state);
1068 if (!uport)
1069 goto out;
1070
1071 if (!tty_io_error(tty)) {
1072 result = uport->mctrl;
1073 spin_lock_irq(&uport->lock);
1074 result |= uport->ops->get_mctrl(uport);
1075 spin_unlock_irq(&uport->lock);
1076 }
1077 out:
1078 mutex_unlock(&port->mutex);
1079 return result;
1080 }
1081
1082 static int
uart_tiocmset(struct tty_struct * tty,unsigned int set,unsigned int clear)1083 uart_tiocmset(struct tty_struct *tty, unsigned int set, unsigned int clear)
1084 {
1085 struct uart_state *state = tty->driver_data;
1086 struct tty_port *port = &state->port;
1087 struct uart_port *uport;
1088 int ret = -EIO;
1089
1090 mutex_lock(&port->mutex);
1091 uport = uart_port_check(state);
1092 if (!uport)
1093 goto out;
1094
1095 if (!tty_io_error(tty)) {
1096 uart_update_mctrl(uport, set, clear);
1097 ret = 0;
1098 }
1099 out:
1100 mutex_unlock(&port->mutex);
1101 return ret;
1102 }
1103
uart_break_ctl(struct tty_struct * tty,int break_state)1104 static int uart_break_ctl(struct tty_struct *tty, int break_state)
1105 {
1106 struct uart_state *state = tty->driver_data;
1107 struct tty_port *port = &state->port;
1108 struct uart_port *uport;
1109 int ret = -EIO;
1110
1111 mutex_lock(&port->mutex);
1112 uport = uart_port_check(state);
1113 if (!uport)
1114 goto out;
1115
1116 if (uport->type != PORT_UNKNOWN && uport->ops->break_ctl)
1117 uport->ops->break_ctl(uport, break_state);
1118 ret = 0;
1119 out:
1120 mutex_unlock(&port->mutex);
1121 return ret;
1122 }
1123
uart_do_autoconfig(struct tty_struct * tty,struct uart_state * state)1124 static int uart_do_autoconfig(struct tty_struct *tty, struct uart_state *state)
1125 {
1126 struct tty_port *port = &state->port;
1127 struct uart_port *uport;
1128 int flags, ret;
1129
1130 if (!capable(CAP_SYS_ADMIN))
1131 return -EPERM;
1132
1133 /*
1134 * Take the per-port semaphore. This prevents count from
1135 * changing, and hence any extra opens of the port while
1136 * we're auto-configuring.
1137 */
1138 if (mutex_lock_interruptible(&port->mutex))
1139 return -ERESTARTSYS;
1140
1141 uport = uart_port_check(state);
1142 if (!uport) {
1143 ret = -EIO;
1144 goto out;
1145 }
1146
1147 ret = -EBUSY;
1148 if (tty_port_users(port) == 1) {
1149 uart_shutdown(tty, state);
1150
1151 /*
1152 * If we already have a port type configured,
1153 * we must release its resources.
1154 */
1155 if (uport->type != PORT_UNKNOWN && uport->ops->release_port)
1156 uport->ops->release_port(uport);
1157
1158 flags = UART_CONFIG_TYPE;
1159 if (uport->flags & UPF_AUTO_IRQ)
1160 flags |= UART_CONFIG_IRQ;
1161
1162 /*
1163 * This will claim the ports resources if
1164 * a port is found.
1165 */
1166 uport->ops->config_port(uport, flags);
1167
1168 ret = uart_startup(tty, state, 1);
1169 if (ret == 0)
1170 tty_port_set_initialized(port, true);
1171 if (ret > 0)
1172 ret = 0;
1173 }
1174 out:
1175 mutex_unlock(&port->mutex);
1176 return ret;
1177 }
1178
uart_enable_ms(struct uart_port * uport)1179 static void uart_enable_ms(struct uart_port *uport)
1180 {
1181 /*
1182 * Force modem status interrupts on
1183 */
1184 if (uport->ops->enable_ms)
1185 uport->ops->enable_ms(uport);
1186 }
1187
1188 /*
1189 * Wait for any of the 4 modem inputs (DCD,RI,DSR,CTS) to change
1190 * - mask passed in arg for lines of interest
1191 * (use |'ed TIOCM_RNG/DSR/CD/CTS for masking)
1192 * Caller should use TIOCGICOUNT to see which one it was
1193 *
1194 * FIXME: This wants extracting into a common all driver implementation
1195 * of TIOCMWAIT using tty_port.
1196 */
uart_wait_modem_status(struct uart_state * state,unsigned long arg)1197 static int uart_wait_modem_status(struct uart_state *state, unsigned long arg)
1198 {
1199 struct uart_port *uport;
1200 struct tty_port *port = &state->port;
1201 DECLARE_WAITQUEUE(wait, current);
1202 struct uart_icount cprev, cnow;
1203 int ret;
1204
1205 /*
1206 * note the counters on entry
1207 */
1208 uport = uart_port_ref(state);
1209 if (!uport)
1210 return -EIO;
1211 spin_lock_irq(&uport->lock);
1212 memcpy(&cprev, &uport->icount, sizeof(struct uart_icount));
1213 uart_enable_ms(uport);
1214 spin_unlock_irq(&uport->lock);
1215
1216 add_wait_queue(&port->delta_msr_wait, &wait);
1217 for (;;) {
1218 spin_lock_irq(&uport->lock);
1219 memcpy(&cnow, &uport->icount, sizeof(struct uart_icount));
1220 spin_unlock_irq(&uport->lock);
1221
1222 set_current_state(TASK_INTERRUPTIBLE);
1223
1224 if (((arg & TIOCM_RNG) && (cnow.rng != cprev.rng)) ||
1225 ((arg & TIOCM_DSR) && (cnow.dsr != cprev.dsr)) ||
1226 ((arg & TIOCM_CD) && (cnow.dcd != cprev.dcd)) ||
1227 ((arg & TIOCM_CTS) && (cnow.cts != cprev.cts))) {
1228 ret = 0;
1229 break;
1230 }
1231
1232 schedule();
1233
1234 /* see if a signal did it */
1235 if (signal_pending(current)) {
1236 ret = -ERESTARTSYS;
1237 break;
1238 }
1239
1240 cprev = cnow;
1241 }
1242 __set_current_state(TASK_RUNNING);
1243 remove_wait_queue(&port->delta_msr_wait, &wait);
1244 uart_port_deref(uport);
1245
1246 return ret;
1247 }
1248
1249 /*
1250 * Get counter of input serial line interrupts (DCD,RI,DSR,CTS)
1251 * Return: write counters to the user passed counter struct
1252 * NB: both 1->0 and 0->1 transitions are counted except for
1253 * RI where only 0->1 is counted.
1254 */
uart_get_icount(struct tty_struct * tty,struct serial_icounter_struct * icount)1255 static int uart_get_icount(struct tty_struct *tty,
1256 struct serial_icounter_struct *icount)
1257 {
1258 struct uart_state *state = tty->driver_data;
1259 struct uart_icount cnow;
1260 struct uart_port *uport;
1261
1262 uport = uart_port_ref(state);
1263 if (!uport)
1264 return -EIO;
1265 spin_lock_irq(&uport->lock);
1266 memcpy(&cnow, &uport->icount, sizeof(struct uart_icount));
1267 spin_unlock_irq(&uport->lock);
1268 uart_port_deref(uport);
1269
1270 icount->cts = cnow.cts;
1271 icount->dsr = cnow.dsr;
1272 icount->rng = cnow.rng;
1273 icount->dcd = cnow.dcd;
1274 icount->rx = cnow.rx;
1275 icount->tx = cnow.tx;
1276 icount->frame = cnow.frame;
1277 icount->overrun = cnow.overrun;
1278 icount->parity = cnow.parity;
1279 icount->brk = cnow.brk;
1280 icount->buf_overrun = cnow.buf_overrun;
1281
1282 return 0;
1283 }
1284
1285 #define SER_RS485_LEGACY_FLAGS (SER_RS485_ENABLED | SER_RS485_RTS_ON_SEND | \
1286 SER_RS485_RTS_AFTER_SEND | SER_RS485_RX_DURING_TX | \
1287 SER_RS485_TERMINATE_BUS)
1288
uart_check_rs485_flags(struct uart_port * port,struct serial_rs485 * rs485)1289 static int uart_check_rs485_flags(struct uart_port *port, struct serial_rs485 *rs485)
1290 {
1291 u32 flags = rs485->flags;
1292
1293 /* Don't return -EINVAL for unsupported legacy flags */
1294 flags &= ~SER_RS485_LEGACY_FLAGS;
1295
1296 /*
1297 * For any bit outside of the legacy ones that is not supported by
1298 * the driver, return -EINVAL.
1299 */
1300 if (flags & ~port->rs485_supported.flags)
1301 return -EINVAL;
1302
1303 /* Asking for address w/o addressing mode? */
1304 if (!(rs485->flags & SER_RS485_ADDRB) &&
1305 (rs485->flags & (SER_RS485_ADDR_RECV|SER_RS485_ADDR_DEST)))
1306 return -EINVAL;
1307
1308 /* Address given but not enabled? */
1309 if (!(rs485->flags & SER_RS485_ADDR_RECV) && rs485->addr_recv)
1310 return -EINVAL;
1311 if (!(rs485->flags & SER_RS485_ADDR_DEST) && rs485->addr_dest)
1312 return -EINVAL;
1313
1314 return 0;
1315 }
1316
uart_sanitize_serial_rs485_delays(struct uart_port * port,struct serial_rs485 * rs485)1317 static void uart_sanitize_serial_rs485_delays(struct uart_port *port,
1318 struct serial_rs485 *rs485)
1319 {
1320 if (!port->rs485_supported.delay_rts_before_send) {
1321 if (rs485->delay_rts_before_send) {
1322 dev_warn_ratelimited(port->dev,
1323 "%s (%d): RTS delay before sending not supported\n",
1324 port->name, port->line);
1325 }
1326 rs485->delay_rts_before_send = 0;
1327 } else if (rs485->delay_rts_before_send > RS485_MAX_RTS_DELAY) {
1328 rs485->delay_rts_before_send = RS485_MAX_RTS_DELAY;
1329 dev_warn_ratelimited(port->dev,
1330 "%s (%d): RTS delay before sending clamped to %u ms\n",
1331 port->name, port->line, rs485->delay_rts_before_send);
1332 }
1333
1334 if (!port->rs485_supported.delay_rts_after_send) {
1335 if (rs485->delay_rts_after_send) {
1336 dev_warn_ratelimited(port->dev,
1337 "%s (%d): RTS delay after sending not supported\n",
1338 port->name, port->line);
1339 }
1340 rs485->delay_rts_after_send = 0;
1341 } else if (rs485->delay_rts_after_send > RS485_MAX_RTS_DELAY) {
1342 rs485->delay_rts_after_send = RS485_MAX_RTS_DELAY;
1343 dev_warn_ratelimited(port->dev,
1344 "%s (%d): RTS delay after sending clamped to %u ms\n",
1345 port->name, port->line, rs485->delay_rts_after_send);
1346 }
1347 }
1348
uart_sanitize_serial_rs485(struct uart_port * port,struct serial_rs485 * rs485)1349 static void uart_sanitize_serial_rs485(struct uart_port *port, struct serial_rs485 *rs485)
1350 {
1351 u32 supported_flags = port->rs485_supported.flags;
1352
1353 if (!(rs485->flags & SER_RS485_ENABLED)) {
1354 memset(rs485, 0, sizeof(*rs485));
1355 return;
1356 }
1357
1358 /* Pick sane settings if the user hasn't */
1359 if ((supported_flags & (SER_RS485_RTS_ON_SEND|SER_RS485_RTS_AFTER_SEND)) &&
1360 !(rs485->flags & SER_RS485_RTS_ON_SEND) ==
1361 !(rs485->flags & SER_RS485_RTS_AFTER_SEND)) {
1362 dev_warn_ratelimited(port->dev,
1363 "%s (%d): invalid RTS setting, using RTS_ON_SEND instead\n",
1364 port->name, port->line);
1365 rs485->flags |= SER_RS485_RTS_ON_SEND;
1366 rs485->flags &= ~SER_RS485_RTS_AFTER_SEND;
1367 supported_flags |= SER_RS485_RTS_ON_SEND|SER_RS485_RTS_AFTER_SEND;
1368 }
1369
1370 rs485->flags &= supported_flags;
1371
1372 uart_sanitize_serial_rs485_delays(port, rs485);
1373
1374 /* Return clean padding area to userspace */
1375 memset(rs485->padding0, 0, sizeof(rs485->padding0));
1376 memset(rs485->padding1, 0, sizeof(rs485->padding1));
1377 }
1378
uart_set_rs485_termination(struct uart_port * port,const struct serial_rs485 * rs485)1379 static void uart_set_rs485_termination(struct uart_port *port,
1380 const struct serial_rs485 *rs485)
1381 {
1382 if (!(rs485->flags & SER_RS485_ENABLED))
1383 return;
1384
1385 gpiod_set_value_cansleep(port->rs485_term_gpio,
1386 !!(rs485->flags & SER_RS485_TERMINATE_BUS));
1387 }
1388
uart_rs485_config(struct uart_port * port)1389 static int uart_rs485_config(struct uart_port *port)
1390 {
1391 struct serial_rs485 *rs485 = &port->rs485;
1392 int ret;
1393
1394 uart_sanitize_serial_rs485(port, rs485);
1395 uart_set_rs485_termination(port, rs485);
1396
1397 ret = port->rs485_config(port, NULL, rs485);
1398 if (ret)
1399 memset(rs485, 0, sizeof(*rs485));
1400
1401 return ret;
1402 }
1403
uart_get_rs485_config(struct uart_port * port,struct serial_rs485 __user * rs485)1404 static int uart_get_rs485_config(struct uart_port *port,
1405 struct serial_rs485 __user *rs485)
1406 {
1407 unsigned long flags;
1408 struct serial_rs485 aux;
1409
1410 spin_lock_irqsave(&port->lock, flags);
1411 aux = port->rs485;
1412 spin_unlock_irqrestore(&port->lock, flags);
1413
1414 if (copy_to_user(rs485, &aux, sizeof(aux)))
1415 return -EFAULT;
1416
1417 return 0;
1418 }
1419
uart_set_rs485_config(struct tty_struct * tty,struct uart_port * port,struct serial_rs485 __user * rs485_user)1420 static int uart_set_rs485_config(struct tty_struct *tty, struct uart_port *port,
1421 struct serial_rs485 __user *rs485_user)
1422 {
1423 struct serial_rs485 rs485;
1424 int ret;
1425 unsigned long flags;
1426
1427 if (!port->rs485_config)
1428 return -ENOTTY;
1429
1430 if (copy_from_user(&rs485, rs485_user, sizeof(*rs485_user)))
1431 return -EFAULT;
1432
1433 ret = uart_check_rs485_flags(port, &rs485);
1434 if (ret)
1435 return ret;
1436 uart_sanitize_serial_rs485(port, &rs485);
1437 uart_set_rs485_termination(port, &rs485);
1438
1439 spin_lock_irqsave(&port->lock, flags);
1440 ret = port->rs485_config(port, &tty->termios, &rs485);
1441 if (!ret) {
1442 port->rs485 = rs485;
1443
1444 /* Reset RTS and other mctrl lines when disabling RS485 */
1445 if (!(rs485.flags & SER_RS485_ENABLED))
1446 port->ops->set_mctrl(port, port->mctrl);
1447 }
1448 spin_unlock_irqrestore(&port->lock, flags);
1449 if (ret)
1450 return ret;
1451
1452 if (copy_to_user(rs485_user, &port->rs485, sizeof(port->rs485)))
1453 return -EFAULT;
1454
1455 return 0;
1456 }
1457
uart_get_iso7816_config(struct uart_port * port,struct serial_iso7816 __user * iso7816)1458 static int uart_get_iso7816_config(struct uart_port *port,
1459 struct serial_iso7816 __user *iso7816)
1460 {
1461 unsigned long flags;
1462 struct serial_iso7816 aux;
1463
1464 if (!port->iso7816_config)
1465 return -ENOTTY;
1466
1467 spin_lock_irqsave(&port->lock, flags);
1468 aux = port->iso7816;
1469 spin_unlock_irqrestore(&port->lock, flags);
1470
1471 if (copy_to_user(iso7816, &aux, sizeof(aux)))
1472 return -EFAULT;
1473
1474 return 0;
1475 }
1476
uart_set_iso7816_config(struct uart_port * port,struct serial_iso7816 __user * iso7816_user)1477 static int uart_set_iso7816_config(struct uart_port *port,
1478 struct serial_iso7816 __user *iso7816_user)
1479 {
1480 struct serial_iso7816 iso7816;
1481 int i, ret;
1482 unsigned long flags;
1483
1484 if (!port->iso7816_config)
1485 return -ENOTTY;
1486
1487 if (copy_from_user(&iso7816, iso7816_user, sizeof(*iso7816_user)))
1488 return -EFAULT;
1489
1490 /*
1491 * There are 5 words reserved for future use. Check that userspace
1492 * doesn't put stuff in there to prevent breakages in the future.
1493 */
1494 for (i = 0; i < 5; i++)
1495 if (iso7816.reserved[i])
1496 return -EINVAL;
1497
1498 spin_lock_irqsave(&port->lock, flags);
1499 ret = port->iso7816_config(port, &iso7816);
1500 spin_unlock_irqrestore(&port->lock, flags);
1501 if (ret)
1502 return ret;
1503
1504 if (copy_to_user(iso7816_user, &port->iso7816, sizeof(port->iso7816)))
1505 return -EFAULT;
1506
1507 return 0;
1508 }
1509
1510 /*
1511 * Called via sys_ioctl. We can use spin_lock_irq() here.
1512 */
1513 static int
uart_ioctl(struct tty_struct * tty,unsigned int cmd,unsigned long arg)1514 uart_ioctl(struct tty_struct *tty, unsigned int cmd, unsigned long arg)
1515 {
1516 struct uart_state *state = tty->driver_data;
1517 struct tty_port *port = &state->port;
1518 struct uart_port *uport;
1519 void __user *uarg = (void __user *)arg;
1520 int ret = -ENOIOCTLCMD;
1521
1522
1523 /*
1524 * These ioctls don't rely on the hardware to be present.
1525 */
1526 switch (cmd) {
1527 case TIOCSERCONFIG:
1528 down_write(&tty->termios_rwsem);
1529 ret = uart_do_autoconfig(tty, state);
1530 up_write(&tty->termios_rwsem);
1531 break;
1532 }
1533
1534 if (ret != -ENOIOCTLCMD)
1535 goto out;
1536
1537 if (tty_io_error(tty)) {
1538 ret = -EIO;
1539 goto out;
1540 }
1541
1542 /*
1543 * The following should only be used when hardware is present.
1544 */
1545 switch (cmd) {
1546 case TIOCMIWAIT:
1547 ret = uart_wait_modem_status(state, arg);
1548 break;
1549 }
1550
1551 if (ret != -ENOIOCTLCMD)
1552 goto out;
1553
1554 /* rs485_config requires more locking than others */
1555 if (cmd == TIOCGRS485)
1556 down_write(&tty->termios_rwsem);
1557
1558 mutex_lock(&port->mutex);
1559 uport = uart_port_check(state);
1560
1561 if (!uport || tty_io_error(tty)) {
1562 ret = -EIO;
1563 goto out_up;
1564 }
1565
1566 /*
1567 * All these rely on hardware being present and need to be
1568 * protected against the tty being hung up.
1569 */
1570
1571 switch (cmd) {
1572 case TIOCSERGETLSR: /* Get line status register */
1573 ret = uart_get_lsr_info(tty, state, uarg);
1574 break;
1575
1576 case TIOCGRS485:
1577 ret = uart_get_rs485_config(uport, uarg);
1578 break;
1579
1580 case TIOCSRS485:
1581 ret = uart_set_rs485_config(tty, uport, uarg);
1582 break;
1583
1584 case TIOCSISO7816:
1585 ret = uart_set_iso7816_config(state->uart_port, uarg);
1586 break;
1587
1588 case TIOCGISO7816:
1589 ret = uart_get_iso7816_config(state->uart_port, uarg);
1590 break;
1591 default:
1592 if (uport->ops->ioctl)
1593 ret = uport->ops->ioctl(uport, cmd, arg);
1594 break;
1595 }
1596 out_up:
1597 mutex_unlock(&port->mutex);
1598 if (cmd == TIOCGRS485)
1599 up_write(&tty->termios_rwsem);
1600 out:
1601 return ret;
1602 }
1603
uart_set_ldisc(struct tty_struct * tty)1604 static void uart_set_ldisc(struct tty_struct *tty)
1605 {
1606 struct uart_state *state = tty->driver_data;
1607 struct uart_port *uport;
1608 struct tty_port *port = &state->port;
1609
1610 if (!tty_port_initialized(port))
1611 return;
1612
1613 mutex_lock(&state->port.mutex);
1614 uport = uart_port_check(state);
1615 if (uport && uport->ops->set_ldisc)
1616 uport->ops->set_ldisc(uport, &tty->termios);
1617 mutex_unlock(&state->port.mutex);
1618 }
1619
uart_set_termios(struct tty_struct * tty,const struct ktermios * old_termios)1620 static void uart_set_termios(struct tty_struct *tty,
1621 const struct ktermios *old_termios)
1622 {
1623 struct uart_state *state = tty->driver_data;
1624 struct uart_port *uport;
1625 unsigned int cflag = tty->termios.c_cflag;
1626 unsigned int iflag_mask = IGNBRK|BRKINT|IGNPAR|PARMRK|INPCK;
1627 bool sw_changed = false;
1628
1629 mutex_lock(&state->port.mutex);
1630 uport = uart_port_check(state);
1631 if (!uport)
1632 goto out;
1633
1634 /*
1635 * Drivers doing software flow control also need to know
1636 * about changes to these input settings.
1637 */
1638 if (uport->flags & UPF_SOFT_FLOW) {
1639 iflag_mask |= IXANY|IXON|IXOFF;
1640 sw_changed =
1641 tty->termios.c_cc[VSTART] != old_termios->c_cc[VSTART] ||
1642 tty->termios.c_cc[VSTOP] != old_termios->c_cc[VSTOP];
1643 }
1644
1645 /*
1646 * These are the bits that are used to setup various
1647 * flags in the low level driver. We can ignore the Bfoo
1648 * bits in c_cflag; c_[io]speed will always be set
1649 * appropriately by set_termios() in tty_ioctl.c
1650 */
1651 if ((cflag ^ old_termios->c_cflag) == 0 &&
1652 tty->termios.c_ospeed == old_termios->c_ospeed &&
1653 tty->termios.c_ispeed == old_termios->c_ispeed &&
1654 ((tty->termios.c_iflag ^ old_termios->c_iflag) & iflag_mask) == 0 &&
1655 !sw_changed) {
1656 goto out;
1657 }
1658
1659 uart_change_speed(tty, state, old_termios);
1660 /* reload cflag from termios; port driver may have overridden flags */
1661 cflag = tty->termios.c_cflag;
1662
1663 /* Handle transition to B0 status */
1664 if ((old_termios->c_cflag & CBAUD) && !(cflag & CBAUD))
1665 uart_clear_mctrl(uport, TIOCM_RTS | TIOCM_DTR);
1666 /* Handle transition away from B0 status */
1667 else if (!(old_termios->c_cflag & CBAUD) && (cflag & CBAUD)) {
1668 unsigned int mask = TIOCM_DTR;
1669
1670 if (!(cflag & CRTSCTS) || !tty_throttled(tty))
1671 mask |= TIOCM_RTS;
1672 uart_set_mctrl(uport, mask);
1673 }
1674 out:
1675 mutex_unlock(&state->port.mutex);
1676 }
1677
1678 /*
1679 * Calls to uart_close() are serialised via the tty_lock in
1680 * drivers/tty/tty_io.c:tty_release()
1681 * drivers/tty/tty_io.c:do_tty_hangup()
1682 */
uart_close(struct tty_struct * tty,struct file * filp)1683 static void uart_close(struct tty_struct *tty, struct file *filp)
1684 {
1685 struct uart_state *state = tty->driver_data;
1686
1687 if (!state) {
1688 struct uart_driver *drv = tty->driver->driver_state;
1689 struct tty_port *port;
1690
1691 state = drv->state + tty->index;
1692 port = &state->port;
1693 spin_lock_irq(&port->lock);
1694 --port->count;
1695 spin_unlock_irq(&port->lock);
1696 return;
1697 }
1698
1699 pr_debug("uart_close(%d) called\n", tty->index);
1700
1701 tty_port_close(tty->port, tty, filp);
1702 }
1703
uart_tty_port_shutdown(struct tty_port * port)1704 static void uart_tty_port_shutdown(struct tty_port *port)
1705 {
1706 struct uart_state *state = container_of(port, struct uart_state, port);
1707 struct uart_port *uport = uart_port_check(state);
1708 char *buf;
1709
1710 /*
1711 * At this point, we stop accepting input. To do this, we
1712 * disable the receive line status interrupts.
1713 */
1714 if (WARN(!uport, "detached port still initialized!\n"))
1715 return;
1716
1717 spin_lock_irq(&uport->lock);
1718 uport->ops->stop_rx(uport);
1719 spin_unlock_irq(&uport->lock);
1720
1721 uart_port_shutdown(port);
1722
1723 /*
1724 * It's possible for shutdown to be called after suspend if we get
1725 * a DCD drop (hangup) at just the right time. Clear suspended bit so
1726 * we don't try to resume a port that has been shutdown.
1727 */
1728 tty_port_set_suspended(port, 0);
1729
1730 /*
1731 * Free the transmit buffer.
1732 */
1733 spin_lock_irq(&uport->lock);
1734 buf = state->xmit.buf;
1735 state->xmit.buf = NULL;
1736 spin_unlock_irq(&uport->lock);
1737
1738 free_page((unsigned long)buf);
1739
1740 uart_change_pm(state, UART_PM_STATE_OFF);
1741 }
1742
uart_wait_until_sent(struct tty_struct * tty,int timeout)1743 static void uart_wait_until_sent(struct tty_struct *tty, int timeout)
1744 {
1745 struct uart_state *state = tty->driver_data;
1746 struct uart_port *port;
1747 unsigned long char_time, expire, fifo_timeout;
1748
1749 port = uart_port_ref(state);
1750 if (!port)
1751 return;
1752
1753 if (port->type == PORT_UNKNOWN || port->fifosize == 0) {
1754 uart_port_deref(port);
1755 return;
1756 }
1757
1758 /*
1759 * Set the check interval to be 1/5 of the estimated time to
1760 * send a single character, and make it at least 1. The check
1761 * interval should also be less than the timeout.
1762 *
1763 * Note: we have to use pretty tight timings here to satisfy
1764 * the NIST-PCTS.
1765 */
1766 char_time = max(nsecs_to_jiffies(port->frame_time / 5), 1UL);
1767
1768 if (timeout && timeout < char_time)
1769 char_time = timeout;
1770
1771 if (!uart_cts_enabled(port)) {
1772 /*
1773 * If the transmitter hasn't cleared in twice the approximate
1774 * amount of time to send the entire FIFO, it probably won't
1775 * ever clear. This assumes the UART isn't doing flow
1776 * control, which is currently the case. Hence, if it ever
1777 * takes longer than FIFO timeout, this is probably due to a
1778 * UART bug of some kind. So, we clamp the timeout parameter at
1779 * 2 * FIFO timeout.
1780 */
1781 fifo_timeout = uart_fifo_timeout(port);
1782 if (timeout == 0 || timeout > 2 * fifo_timeout)
1783 timeout = 2 * fifo_timeout;
1784 }
1785
1786 expire = jiffies + timeout;
1787
1788 pr_debug("uart_wait_until_sent(%d), jiffies=%lu, expire=%lu...\n",
1789 port->line, jiffies, expire);
1790
1791 /*
1792 * Check whether the transmitter is empty every 'char_time'.
1793 * 'timeout' / 'expire' give us the maximum amount of time
1794 * we wait.
1795 */
1796 while (!port->ops->tx_empty(port)) {
1797 msleep_interruptible(jiffies_to_msecs(char_time));
1798 if (signal_pending(current))
1799 break;
1800 if (timeout && time_after(jiffies, expire))
1801 break;
1802 }
1803 uart_port_deref(port);
1804 }
1805
1806 /*
1807 * Calls to uart_hangup() are serialised by the tty_lock in
1808 * drivers/tty/tty_io.c:do_tty_hangup()
1809 * This runs from a workqueue and can sleep for a _short_ time only.
1810 */
uart_hangup(struct tty_struct * tty)1811 static void uart_hangup(struct tty_struct *tty)
1812 {
1813 struct uart_state *state = tty->driver_data;
1814 struct tty_port *port = &state->port;
1815 struct uart_port *uport;
1816 unsigned long flags;
1817
1818 pr_debug("uart_hangup(%d)\n", tty->index);
1819
1820 mutex_lock(&port->mutex);
1821 uport = uart_port_check(state);
1822 WARN(!uport, "hangup of detached port!\n");
1823
1824 if (tty_port_active(port)) {
1825 uart_flush_buffer(tty);
1826 uart_shutdown(tty, state);
1827 spin_lock_irqsave(&port->lock, flags);
1828 port->count = 0;
1829 spin_unlock_irqrestore(&port->lock, flags);
1830 tty_port_set_active(port, 0);
1831 tty_port_tty_set(port, NULL);
1832 if (uport && !uart_console(uport))
1833 uart_change_pm(state, UART_PM_STATE_OFF);
1834 wake_up_interruptible(&port->open_wait);
1835 wake_up_interruptible(&port->delta_msr_wait);
1836 }
1837 mutex_unlock(&port->mutex);
1838 }
1839
1840 /* uport == NULL if uart_port has already been removed */
uart_port_shutdown(struct tty_port * port)1841 static void uart_port_shutdown(struct tty_port *port)
1842 {
1843 struct uart_state *state = container_of(port, struct uart_state, port);
1844 struct uart_port *uport = uart_port_check(state);
1845
1846 /*
1847 * clear delta_msr_wait queue to avoid mem leaks: we may free
1848 * the irq here so the queue might never be woken up. Note
1849 * that we won't end up waiting on delta_msr_wait again since
1850 * any outstanding file descriptors should be pointing at
1851 * hung_up_tty_fops now.
1852 */
1853 wake_up_interruptible(&port->delta_msr_wait);
1854
1855 if (uport) {
1856 /* Free the IRQ and disable the port. */
1857 uport->ops->shutdown(uport);
1858
1859 /* Ensure that the IRQ handler isn't running on another CPU. */
1860 synchronize_irq(uport->irq);
1861 }
1862 }
1863
uart_carrier_raised(struct tty_port * port)1864 static int uart_carrier_raised(struct tty_port *port)
1865 {
1866 struct uart_state *state = container_of(port, struct uart_state, port);
1867 struct uart_port *uport;
1868 int mctrl;
1869
1870 uport = uart_port_ref(state);
1871 /*
1872 * Should never observe uport == NULL since checks for hangup should
1873 * abort the tty_port_block_til_ready() loop before checking for carrier
1874 * raised -- but report carrier raised if it does anyway so open will
1875 * continue and not sleep
1876 */
1877 if (WARN_ON(!uport))
1878 return 1;
1879 spin_lock_irq(&uport->lock);
1880 uart_enable_ms(uport);
1881 mctrl = uport->ops->get_mctrl(uport);
1882 spin_unlock_irq(&uport->lock);
1883 uart_port_deref(uport);
1884 if (mctrl & TIOCM_CAR)
1885 return 1;
1886 return 0;
1887 }
1888
uart_dtr_rts(struct tty_port * port,int raise)1889 static void uart_dtr_rts(struct tty_port *port, int raise)
1890 {
1891 struct uart_state *state = container_of(port, struct uart_state, port);
1892 struct uart_port *uport;
1893
1894 uport = uart_port_ref(state);
1895 if (!uport)
1896 return;
1897 uart_port_dtr_rts(uport, raise);
1898 uart_port_deref(uport);
1899 }
1900
uart_install(struct tty_driver * driver,struct tty_struct * tty)1901 static int uart_install(struct tty_driver *driver, struct tty_struct *tty)
1902 {
1903 struct uart_driver *drv = driver->driver_state;
1904 struct uart_state *state = drv->state + tty->index;
1905
1906 tty->driver_data = state;
1907
1908 return tty_standard_install(driver, tty);
1909 }
1910
1911 /*
1912 * Calls to uart_open are serialised by the tty_lock in
1913 * drivers/tty/tty_io.c:tty_open()
1914 * Note that if this fails, then uart_close() _will_ be called.
1915 *
1916 * In time, we want to scrap the "opening nonpresent ports"
1917 * behaviour and implement an alternative way for setserial
1918 * to set base addresses/ports/types. This will allow us to
1919 * get rid of a certain amount of extra tests.
1920 */
uart_open(struct tty_struct * tty,struct file * filp)1921 static int uart_open(struct tty_struct *tty, struct file *filp)
1922 {
1923 struct uart_state *state = tty->driver_data;
1924 int retval;
1925
1926 retval = tty_port_open(&state->port, tty, filp);
1927 if (retval > 0)
1928 retval = 0;
1929
1930 return retval;
1931 }
1932
uart_port_activate(struct tty_port * port,struct tty_struct * tty)1933 static int uart_port_activate(struct tty_port *port, struct tty_struct *tty)
1934 {
1935 struct uart_state *state = container_of(port, struct uart_state, port);
1936 struct uart_port *uport;
1937 int ret;
1938
1939 uport = uart_port_check(state);
1940 if (!uport || uport->flags & UPF_DEAD)
1941 return -ENXIO;
1942
1943 /*
1944 * Start up the serial port.
1945 */
1946 ret = uart_startup(tty, state, 0);
1947 if (ret > 0)
1948 tty_port_set_active(port, 1);
1949
1950 return ret;
1951 }
1952
uart_type(struct uart_port * port)1953 static const char *uart_type(struct uart_port *port)
1954 {
1955 const char *str = NULL;
1956
1957 if (port->ops->type)
1958 str = port->ops->type(port);
1959
1960 if (!str)
1961 str = "unknown";
1962
1963 return str;
1964 }
1965
1966 #ifdef CONFIG_PROC_FS
1967
uart_line_info(struct seq_file * m,struct uart_driver * drv,int i)1968 static void uart_line_info(struct seq_file *m, struct uart_driver *drv, int i)
1969 {
1970 struct uart_state *state = drv->state + i;
1971 struct tty_port *port = &state->port;
1972 enum uart_pm_state pm_state;
1973 struct uart_port *uport;
1974 char stat_buf[32];
1975 unsigned int status;
1976 int mmio;
1977
1978 mutex_lock(&port->mutex);
1979 uport = uart_port_check(state);
1980 if (!uport)
1981 goto out;
1982
1983 mmio = uport->iotype >= UPIO_MEM;
1984 seq_printf(m, "%d: uart:%s %s%08llX irq:%d",
1985 uport->line, uart_type(uport),
1986 mmio ? "mmio:0x" : "port:",
1987 mmio ? (unsigned long long)uport->mapbase
1988 : (unsigned long long)uport->iobase,
1989 uport->irq);
1990
1991 if (uport->type == PORT_UNKNOWN) {
1992 seq_putc(m, '\n');
1993 goto out;
1994 }
1995
1996 if (capable(CAP_SYS_ADMIN)) {
1997 pm_state = state->pm_state;
1998 if (pm_state != UART_PM_STATE_ON)
1999 uart_change_pm(state, UART_PM_STATE_ON);
2000 spin_lock_irq(&uport->lock);
2001 status = uport->ops->get_mctrl(uport);
2002 spin_unlock_irq(&uport->lock);
2003 if (pm_state != UART_PM_STATE_ON)
2004 uart_change_pm(state, pm_state);
2005
2006 seq_printf(m, " tx:%d rx:%d",
2007 uport->icount.tx, uport->icount.rx);
2008 if (uport->icount.frame)
2009 seq_printf(m, " fe:%d", uport->icount.frame);
2010 if (uport->icount.parity)
2011 seq_printf(m, " pe:%d", uport->icount.parity);
2012 if (uport->icount.brk)
2013 seq_printf(m, " brk:%d", uport->icount.brk);
2014 if (uport->icount.overrun)
2015 seq_printf(m, " oe:%d", uport->icount.overrun);
2016 if (uport->icount.buf_overrun)
2017 seq_printf(m, " bo:%d", uport->icount.buf_overrun);
2018
2019 #define INFOBIT(bit, str) \
2020 if (uport->mctrl & (bit)) \
2021 strncat(stat_buf, (str), sizeof(stat_buf) - \
2022 strlen(stat_buf) - 2)
2023 #define STATBIT(bit, str) \
2024 if (status & (bit)) \
2025 strncat(stat_buf, (str), sizeof(stat_buf) - \
2026 strlen(stat_buf) - 2)
2027
2028 stat_buf[0] = '\0';
2029 stat_buf[1] = '\0';
2030 INFOBIT(TIOCM_RTS, "|RTS");
2031 STATBIT(TIOCM_CTS, "|CTS");
2032 INFOBIT(TIOCM_DTR, "|DTR");
2033 STATBIT(TIOCM_DSR, "|DSR");
2034 STATBIT(TIOCM_CAR, "|CD");
2035 STATBIT(TIOCM_RNG, "|RI");
2036 if (stat_buf[0])
2037 stat_buf[0] = ' ';
2038
2039 seq_puts(m, stat_buf);
2040 }
2041 seq_putc(m, '\n');
2042 #undef STATBIT
2043 #undef INFOBIT
2044 out:
2045 mutex_unlock(&port->mutex);
2046 }
2047
uart_proc_show(struct seq_file * m,void * v)2048 static int uart_proc_show(struct seq_file *m, void *v)
2049 {
2050 struct tty_driver *ttydrv = m->private;
2051 struct uart_driver *drv = ttydrv->driver_state;
2052 int i;
2053
2054 seq_printf(m, "serinfo:1.0 driver%s%s revision:%s\n", "", "", "");
2055 for (i = 0; i < drv->nr; i++)
2056 uart_line_info(m, drv, i);
2057 return 0;
2058 }
2059 #endif
2060
uart_port_spin_lock_init(struct uart_port * port)2061 static void uart_port_spin_lock_init(struct uart_port *port)
2062 {
2063 spin_lock_init(&port->lock);
2064 lockdep_set_class(&port->lock, &port_lock_key);
2065 }
2066
2067 #if defined(CONFIG_SERIAL_CORE_CONSOLE) || defined(CONFIG_CONSOLE_POLL)
2068 /**
2069 * uart_console_write - write a console message to a serial port
2070 * @port: the port to write the message
2071 * @s: array of characters
2072 * @count: number of characters in string to write
2073 * @putchar: function to write character to port
2074 */
uart_console_write(struct uart_port * port,const char * s,unsigned int count,void (* putchar)(struct uart_port *,unsigned char))2075 void uart_console_write(struct uart_port *port, const char *s,
2076 unsigned int count,
2077 void (*putchar)(struct uart_port *, unsigned char))
2078 {
2079 unsigned int i;
2080
2081 for (i = 0; i < count; i++, s++) {
2082 if (*s == '\n')
2083 putchar(port, '\r');
2084 putchar(port, *s);
2085 }
2086 }
2087 EXPORT_SYMBOL_GPL(uart_console_write);
2088
2089 /**
2090 * uart_get_console - get uart port for console
2091 * @ports: ports to search in
2092 * @nr: number of @ports
2093 * @co: console to search for
2094 * Returns: uart_port for the console @co
2095 *
2096 * Check whether an invalid uart number has been specified (as @co->index), and
2097 * if so, search for the first available port that does have console support.
2098 */
2099 struct uart_port * __init
uart_get_console(struct uart_port * ports,int nr,struct console * co)2100 uart_get_console(struct uart_port *ports, int nr, struct console *co)
2101 {
2102 int idx = co->index;
2103
2104 if (idx < 0 || idx >= nr || (ports[idx].iobase == 0 &&
2105 ports[idx].membase == NULL))
2106 for (idx = 0; idx < nr; idx++)
2107 if (ports[idx].iobase != 0 ||
2108 ports[idx].membase != NULL)
2109 break;
2110
2111 co->index = idx;
2112
2113 return ports + idx;
2114 }
2115
2116 /**
2117 * uart_parse_earlycon - Parse earlycon options
2118 * @p: ptr to 2nd field (ie., just beyond '<name>,')
2119 * @iotype: ptr for decoded iotype (out)
2120 * @addr: ptr for decoded mapbase/iobase (out)
2121 * @options: ptr for <options> field; %NULL if not present (out)
2122 *
2123 * Decodes earlycon kernel command line parameters of the form:
2124 * * earlycon=<name>,io|mmio|mmio16|mmio32|mmio32be|mmio32native,<addr>,<options>
2125 * * console=<name>,io|mmio|mmio16|mmio32|mmio32be|mmio32native,<addr>,<options>
2126 *
2127 * The optional form:
2128 * * earlycon=<name>,0x<addr>,<options>
2129 * * console=<name>,0x<addr>,<options>
2130 *
2131 * is also accepted; the returned @iotype will be %UPIO_MEM.
2132 *
2133 * Returns: 0 on success or -%EINVAL on failure
2134 */
uart_parse_earlycon(char * p,unsigned char * iotype,resource_size_t * addr,char ** options)2135 int uart_parse_earlycon(char *p, unsigned char *iotype, resource_size_t *addr,
2136 char **options)
2137 {
2138 if (strncmp(p, "mmio,", 5) == 0) {
2139 *iotype = UPIO_MEM;
2140 p += 5;
2141 } else if (strncmp(p, "mmio16,", 7) == 0) {
2142 *iotype = UPIO_MEM16;
2143 p += 7;
2144 } else if (strncmp(p, "mmio32,", 7) == 0) {
2145 *iotype = UPIO_MEM32;
2146 p += 7;
2147 } else if (strncmp(p, "mmio32be,", 9) == 0) {
2148 *iotype = UPIO_MEM32BE;
2149 p += 9;
2150 } else if (strncmp(p, "mmio32native,", 13) == 0) {
2151 *iotype = IS_ENABLED(CONFIG_CPU_BIG_ENDIAN) ?
2152 UPIO_MEM32BE : UPIO_MEM32;
2153 p += 13;
2154 } else if (strncmp(p, "io,", 3) == 0) {
2155 *iotype = UPIO_PORT;
2156 p += 3;
2157 } else if (strncmp(p, "0x", 2) == 0) {
2158 *iotype = UPIO_MEM;
2159 } else {
2160 return -EINVAL;
2161 }
2162
2163 /*
2164 * Before you replace it with kstrtoull(), think about options separator
2165 * (',') it will not tolerate
2166 */
2167 *addr = simple_strtoull(p, NULL, 0);
2168 p = strchr(p, ',');
2169 if (p)
2170 p++;
2171
2172 *options = p;
2173 return 0;
2174 }
2175 EXPORT_SYMBOL_GPL(uart_parse_earlycon);
2176
2177 /**
2178 * uart_parse_options - Parse serial port baud/parity/bits/flow control.
2179 * @options: pointer to option string
2180 * @baud: pointer to an 'int' variable for the baud rate.
2181 * @parity: pointer to an 'int' variable for the parity.
2182 * @bits: pointer to an 'int' variable for the number of data bits.
2183 * @flow: pointer to an 'int' variable for the flow control character.
2184 *
2185 * uart_parse_options() decodes a string containing the serial console
2186 * options. The format of the string is <baud><parity><bits><flow>,
2187 * eg: 115200n8r
2188 */
2189 void
uart_parse_options(const char * options,int * baud,int * parity,int * bits,int * flow)2190 uart_parse_options(const char *options, int *baud, int *parity,
2191 int *bits, int *flow)
2192 {
2193 const char *s = options;
2194
2195 *baud = simple_strtoul(s, NULL, 10);
2196 while (*s >= '0' && *s <= '9')
2197 s++;
2198 if (*s)
2199 *parity = *s++;
2200 if (*s)
2201 *bits = *s++ - '0';
2202 if (*s)
2203 *flow = *s;
2204 }
2205 EXPORT_SYMBOL_GPL(uart_parse_options);
2206
2207 /**
2208 * uart_set_options - setup the serial console parameters
2209 * @port: pointer to the serial ports uart_port structure
2210 * @co: console pointer
2211 * @baud: baud rate
2212 * @parity: parity character - 'n' (none), 'o' (odd), 'e' (even)
2213 * @bits: number of data bits
2214 * @flow: flow control character - 'r' (rts)
2215 */
2216 int
uart_set_options(struct uart_port * port,struct console * co,int baud,int parity,int bits,int flow)2217 uart_set_options(struct uart_port *port, struct console *co,
2218 int baud, int parity, int bits, int flow)
2219 {
2220 struct ktermios termios;
2221 static struct ktermios dummy;
2222
2223 /*
2224 * Ensure that the serial-console lock is initialised early.
2225 *
2226 * Note that the console-enabled check is needed because of kgdboc,
2227 * which can end up calling uart_set_options() for an already enabled
2228 * console via tty_find_polling_driver() and uart_poll_init().
2229 */
2230 if (!uart_console_enabled(port) && !port->console_reinit)
2231 uart_port_spin_lock_init(port);
2232
2233 memset(&termios, 0, sizeof(struct ktermios));
2234
2235 termios.c_cflag |= CREAD | HUPCL | CLOCAL;
2236 tty_termios_encode_baud_rate(&termios, baud, baud);
2237
2238 if (bits == 7)
2239 termios.c_cflag |= CS7;
2240 else
2241 termios.c_cflag |= CS8;
2242
2243 switch (parity) {
2244 case 'o': case 'O':
2245 termios.c_cflag |= PARODD;
2246 fallthrough;
2247 case 'e': case 'E':
2248 termios.c_cflag |= PARENB;
2249 break;
2250 }
2251
2252 if (flow == 'r')
2253 termios.c_cflag |= CRTSCTS;
2254
2255 /*
2256 * some uarts on other side don't support no flow control.
2257 * So we set * DTR in host uart to make them happy
2258 */
2259 port->mctrl |= TIOCM_DTR;
2260
2261 port->ops->set_termios(port, &termios, &dummy);
2262 /*
2263 * Allow the setting of the UART parameters with a NULL console
2264 * too:
2265 */
2266 if (co) {
2267 co->cflag = termios.c_cflag;
2268 co->ispeed = termios.c_ispeed;
2269 co->ospeed = termios.c_ospeed;
2270 }
2271
2272 return 0;
2273 }
2274 EXPORT_SYMBOL_GPL(uart_set_options);
2275 #endif /* CONFIG_SERIAL_CORE_CONSOLE */
2276
2277 /**
2278 * uart_change_pm - set power state of the port
2279 *
2280 * @state: port descriptor
2281 * @pm_state: new state
2282 *
2283 * Locking: port->mutex has to be held
2284 */
uart_change_pm(struct uart_state * state,enum uart_pm_state pm_state)2285 static void uart_change_pm(struct uart_state *state,
2286 enum uart_pm_state pm_state)
2287 {
2288 struct uart_port *port = uart_port_check(state);
2289
2290 if (state->pm_state != pm_state) {
2291 if (port && port->ops->pm)
2292 port->ops->pm(port, pm_state, state->pm_state);
2293 state->pm_state = pm_state;
2294 }
2295 }
2296
2297 struct uart_match {
2298 struct uart_port *port;
2299 struct uart_driver *driver;
2300 };
2301
serial_match_port(struct device * dev,void * data)2302 static int serial_match_port(struct device *dev, void *data)
2303 {
2304 struct uart_match *match = data;
2305 struct tty_driver *tty_drv = match->driver->tty_driver;
2306 dev_t devt = MKDEV(tty_drv->major, tty_drv->minor_start) +
2307 match->port->line;
2308
2309 return dev->devt == devt; /* Actually, only one tty per port */
2310 }
2311
uart_suspend_port(struct uart_driver * drv,struct uart_port * uport)2312 int uart_suspend_port(struct uart_driver *drv, struct uart_port *uport)
2313 {
2314 struct uart_state *state = drv->state + uport->line;
2315 struct tty_port *port = &state->port;
2316 struct device *tty_dev;
2317 struct uart_match match = {uport, drv};
2318
2319 mutex_lock(&port->mutex);
2320
2321 tty_dev = device_find_child(uport->dev, &match, serial_match_port);
2322 if (tty_dev && device_may_wakeup(tty_dev)) {
2323 enable_irq_wake(uport->irq);
2324 put_device(tty_dev);
2325 mutex_unlock(&port->mutex);
2326 return 0;
2327 }
2328 put_device(tty_dev);
2329
2330 /*
2331 * Nothing to do if the console is not suspending
2332 * except stop_rx to prevent any asynchronous data
2333 * over RX line. However ensure that we will be
2334 * able to Re-start_rx later.
2335 */
2336 if (!console_suspend_enabled && uart_console(uport)) {
2337 if (uport->ops->start_rx)
2338 uport->ops->stop_rx(uport);
2339 goto unlock;
2340 }
2341
2342 uport->suspended = 1;
2343
2344 if (tty_port_initialized(port)) {
2345 const struct uart_ops *ops = uport->ops;
2346 int tries;
2347 unsigned int mctrl;
2348
2349 tty_port_set_suspended(port, 1);
2350 tty_port_set_initialized(port, 0);
2351
2352 spin_lock_irq(&uport->lock);
2353 ops->stop_tx(uport);
2354 if (!(uport->rs485.flags & SER_RS485_ENABLED))
2355 ops->set_mctrl(uport, 0);
2356 /* save mctrl so it can be restored on resume */
2357 mctrl = uport->mctrl;
2358 uport->mctrl = 0;
2359 ops->stop_rx(uport);
2360 spin_unlock_irq(&uport->lock);
2361
2362 /*
2363 * Wait for the transmitter to empty.
2364 */
2365 for (tries = 3; !ops->tx_empty(uport) && tries; tries--)
2366 msleep(10);
2367 if (!tries)
2368 dev_err(uport->dev, "%s: Unable to drain transmitter\n",
2369 uport->name);
2370
2371 ops->shutdown(uport);
2372 uport->mctrl = mctrl;
2373 }
2374
2375 /*
2376 * Disable the console device before suspending.
2377 */
2378 if (uart_console(uport))
2379 console_stop(uport->cons);
2380
2381 uart_change_pm(state, UART_PM_STATE_OFF);
2382 unlock:
2383 mutex_unlock(&port->mutex);
2384
2385 return 0;
2386 }
2387 EXPORT_SYMBOL(uart_suspend_port);
2388
uart_resume_port(struct uart_driver * drv,struct uart_port * uport)2389 int uart_resume_port(struct uart_driver *drv, struct uart_port *uport)
2390 {
2391 struct uart_state *state = drv->state + uport->line;
2392 struct tty_port *port = &state->port;
2393 struct device *tty_dev;
2394 struct uart_match match = {uport, drv};
2395 struct ktermios termios;
2396
2397 mutex_lock(&port->mutex);
2398
2399 tty_dev = device_find_child(uport->dev, &match, serial_match_port);
2400 if (!uport->suspended && device_may_wakeup(tty_dev)) {
2401 if (irqd_is_wakeup_set(irq_get_irq_data((uport->irq))))
2402 disable_irq_wake(uport->irq);
2403 put_device(tty_dev);
2404 mutex_unlock(&port->mutex);
2405 return 0;
2406 }
2407 put_device(tty_dev);
2408 uport->suspended = 0;
2409
2410 /*
2411 * Re-enable the console device after suspending.
2412 */
2413 if (uart_console(uport)) {
2414 /*
2415 * First try to use the console cflag setting.
2416 */
2417 memset(&termios, 0, sizeof(struct ktermios));
2418 termios.c_cflag = uport->cons->cflag;
2419 termios.c_ispeed = uport->cons->ispeed;
2420 termios.c_ospeed = uport->cons->ospeed;
2421
2422 /*
2423 * If that's unset, use the tty termios setting.
2424 */
2425 if (port->tty && termios.c_cflag == 0)
2426 termios = port->tty->termios;
2427
2428 if (console_suspend_enabled)
2429 uart_change_pm(state, UART_PM_STATE_ON);
2430 uport->ops->set_termios(uport, &termios, NULL);
2431 if (!console_suspend_enabled && uport->ops->start_rx)
2432 uport->ops->start_rx(uport);
2433 if (console_suspend_enabled)
2434 console_start(uport->cons);
2435 }
2436
2437 if (tty_port_suspended(port)) {
2438 const struct uart_ops *ops = uport->ops;
2439 int ret;
2440
2441 uart_change_pm(state, UART_PM_STATE_ON);
2442 spin_lock_irq(&uport->lock);
2443 if (!(uport->rs485.flags & SER_RS485_ENABLED))
2444 ops->set_mctrl(uport, 0);
2445 spin_unlock_irq(&uport->lock);
2446 if (console_suspend_enabled || !uart_console(uport)) {
2447 /* Protected by port mutex for now */
2448 struct tty_struct *tty = port->tty;
2449
2450 ret = ops->startup(uport);
2451 if (ret == 0) {
2452 if (tty)
2453 uart_change_speed(tty, state, NULL);
2454 spin_lock_irq(&uport->lock);
2455 if (!(uport->rs485.flags & SER_RS485_ENABLED))
2456 ops->set_mctrl(uport, uport->mctrl);
2457 else
2458 uart_rs485_config(uport);
2459 ops->start_tx(uport);
2460 spin_unlock_irq(&uport->lock);
2461 tty_port_set_initialized(port, 1);
2462 } else {
2463 /*
2464 * Failed to resume - maybe hardware went away?
2465 * Clear the "initialized" flag so we won't try
2466 * to call the low level drivers shutdown method.
2467 */
2468 uart_shutdown(tty, state);
2469 }
2470 }
2471
2472 tty_port_set_suspended(port, 0);
2473 }
2474
2475 mutex_unlock(&port->mutex);
2476
2477 return 0;
2478 }
2479 EXPORT_SYMBOL(uart_resume_port);
2480
2481 static inline void
uart_report_port(struct uart_driver * drv,struct uart_port * port)2482 uart_report_port(struct uart_driver *drv, struct uart_port *port)
2483 {
2484 char address[64];
2485
2486 switch (port->iotype) {
2487 case UPIO_PORT:
2488 snprintf(address, sizeof(address), "I/O 0x%lx", port->iobase);
2489 break;
2490 case UPIO_HUB6:
2491 snprintf(address, sizeof(address),
2492 "I/O 0x%lx offset 0x%x", port->iobase, port->hub6);
2493 break;
2494 case UPIO_MEM:
2495 case UPIO_MEM16:
2496 case UPIO_MEM32:
2497 case UPIO_MEM32BE:
2498 case UPIO_AU:
2499 case UPIO_TSI:
2500 snprintf(address, sizeof(address),
2501 "MMIO 0x%llx", (unsigned long long)port->mapbase);
2502 break;
2503 default:
2504 strscpy(address, "*unknown*", sizeof(address));
2505 break;
2506 }
2507
2508 pr_info("%s%s%s at %s (irq = %d, base_baud = %d) is a %s\n",
2509 port->dev ? dev_name(port->dev) : "",
2510 port->dev ? ": " : "",
2511 port->name,
2512 address, port->irq, port->uartclk / 16, uart_type(port));
2513
2514 /* The magic multiplier feature is a bit obscure, so report it too. */
2515 if (port->flags & UPF_MAGIC_MULTIPLIER)
2516 pr_info("%s%s%s extra baud rates supported: %d, %d",
2517 port->dev ? dev_name(port->dev) : "",
2518 port->dev ? ": " : "",
2519 port->name,
2520 port->uartclk / 8, port->uartclk / 4);
2521 }
2522
2523 static void
uart_configure_port(struct uart_driver * drv,struct uart_state * state,struct uart_port * port)2524 uart_configure_port(struct uart_driver *drv, struct uart_state *state,
2525 struct uart_port *port)
2526 {
2527 unsigned int flags;
2528
2529 /*
2530 * If there isn't a port here, don't do anything further.
2531 */
2532 if (!port->iobase && !port->mapbase && !port->membase)
2533 return;
2534
2535 /*
2536 * Now do the auto configuration stuff. Note that config_port
2537 * is expected to claim the resources and map the port for us.
2538 */
2539 flags = 0;
2540 if (port->flags & UPF_AUTO_IRQ)
2541 flags |= UART_CONFIG_IRQ;
2542 if (port->flags & UPF_BOOT_AUTOCONF) {
2543 if (!(port->flags & UPF_FIXED_TYPE)) {
2544 port->type = PORT_UNKNOWN;
2545 flags |= UART_CONFIG_TYPE;
2546 }
2547 port->ops->config_port(port, flags);
2548 }
2549
2550 if (port->type != PORT_UNKNOWN) {
2551 unsigned long flags;
2552
2553 uart_report_port(drv, port);
2554
2555 /* Power up port for set_mctrl() */
2556 uart_change_pm(state, UART_PM_STATE_ON);
2557
2558 /*
2559 * Ensure that the modem control lines are de-activated.
2560 * keep the DTR setting that is set in uart_set_options()
2561 * We probably don't need a spinlock around this, but
2562 */
2563 spin_lock_irqsave(&port->lock, flags);
2564 port->mctrl &= TIOCM_DTR;
2565 if (!(port->rs485.flags & SER_RS485_ENABLED))
2566 port->ops->set_mctrl(port, port->mctrl);
2567 else
2568 uart_rs485_config(port);
2569 spin_unlock_irqrestore(&port->lock, flags);
2570
2571 /*
2572 * If this driver supports console, and it hasn't been
2573 * successfully registered yet, try to re-register it.
2574 * It may be that the port was not available.
2575 */
2576 if (port->cons && !(port->cons->flags & CON_ENABLED))
2577 register_console(port->cons);
2578
2579 /*
2580 * Power down all ports by default, except the
2581 * console if we have one.
2582 */
2583 if (!uart_console(port))
2584 uart_change_pm(state, UART_PM_STATE_OFF);
2585 }
2586 }
2587
2588 #ifdef CONFIG_CONSOLE_POLL
2589
uart_poll_init(struct tty_driver * driver,int line,char * options)2590 static int uart_poll_init(struct tty_driver *driver, int line, char *options)
2591 {
2592 struct uart_driver *drv = driver->driver_state;
2593 struct uart_state *state = drv->state + line;
2594 struct tty_port *tport;
2595 struct uart_port *port;
2596 int baud = 9600;
2597 int bits = 8;
2598 int parity = 'n';
2599 int flow = 'n';
2600 int ret = 0;
2601
2602 tport = &state->port;
2603 mutex_lock(&tport->mutex);
2604
2605 port = uart_port_check(state);
2606 if (!port || !(port->ops->poll_get_char && port->ops->poll_put_char)) {
2607 ret = -1;
2608 goto out;
2609 }
2610
2611 if (port->ops->poll_init) {
2612 /*
2613 * We don't set initialized as we only initialized the hw,
2614 * e.g. state->xmit is still uninitialized.
2615 */
2616 if (!tty_port_initialized(tport))
2617 ret = port->ops->poll_init(port);
2618 }
2619
2620 if (!ret && options) {
2621 uart_parse_options(options, &baud, &parity, &bits, &flow);
2622 ret = uart_set_options(port, NULL, baud, parity, bits, flow);
2623 }
2624 out:
2625 mutex_unlock(&tport->mutex);
2626 return ret;
2627 }
2628
uart_poll_get_char(struct tty_driver * driver,int line)2629 static int uart_poll_get_char(struct tty_driver *driver, int line)
2630 {
2631 struct uart_driver *drv = driver->driver_state;
2632 struct uart_state *state = drv->state + line;
2633 struct uart_port *port;
2634 int ret = -1;
2635
2636 port = uart_port_ref(state);
2637 if (port) {
2638 ret = port->ops->poll_get_char(port);
2639 uart_port_deref(port);
2640 }
2641
2642 return ret;
2643 }
2644
uart_poll_put_char(struct tty_driver * driver,int line,char ch)2645 static void uart_poll_put_char(struct tty_driver *driver, int line, char ch)
2646 {
2647 struct uart_driver *drv = driver->driver_state;
2648 struct uart_state *state = drv->state + line;
2649 struct uart_port *port;
2650
2651 port = uart_port_ref(state);
2652 if (!port)
2653 return;
2654
2655 if (ch == '\n')
2656 port->ops->poll_put_char(port, '\r');
2657 port->ops->poll_put_char(port, ch);
2658 uart_port_deref(port);
2659 }
2660 #endif
2661
2662 static const struct tty_operations uart_ops = {
2663 .install = uart_install,
2664 .open = uart_open,
2665 .close = uart_close,
2666 .write = uart_write,
2667 .put_char = uart_put_char,
2668 .flush_chars = uart_flush_chars,
2669 .write_room = uart_write_room,
2670 .chars_in_buffer= uart_chars_in_buffer,
2671 .flush_buffer = uart_flush_buffer,
2672 .ioctl = uart_ioctl,
2673 .throttle = uart_throttle,
2674 .unthrottle = uart_unthrottle,
2675 .send_xchar = uart_send_xchar,
2676 .set_termios = uart_set_termios,
2677 .set_ldisc = uart_set_ldisc,
2678 .stop = uart_stop,
2679 .start = uart_start,
2680 .hangup = uart_hangup,
2681 .break_ctl = uart_break_ctl,
2682 .wait_until_sent= uart_wait_until_sent,
2683 #ifdef CONFIG_PROC_FS
2684 .proc_show = uart_proc_show,
2685 #endif
2686 .tiocmget = uart_tiocmget,
2687 .tiocmset = uart_tiocmset,
2688 .set_serial = uart_set_info_user,
2689 .get_serial = uart_get_info_user,
2690 .get_icount = uart_get_icount,
2691 #ifdef CONFIG_CONSOLE_POLL
2692 .poll_init = uart_poll_init,
2693 .poll_get_char = uart_poll_get_char,
2694 .poll_put_char = uart_poll_put_char,
2695 #endif
2696 };
2697
2698 static const struct tty_port_operations uart_port_ops = {
2699 .carrier_raised = uart_carrier_raised,
2700 .dtr_rts = uart_dtr_rts,
2701 .activate = uart_port_activate,
2702 .shutdown = uart_tty_port_shutdown,
2703 };
2704
2705 /**
2706 * uart_register_driver - register a driver with the uart core layer
2707 * @drv: low level driver structure
2708 *
2709 * Register a uart driver with the core driver. We in turn register with the
2710 * tty layer, and initialise the core driver per-port state.
2711 *
2712 * We have a proc file in /proc/tty/driver which is named after the normal
2713 * driver.
2714 *
2715 * @drv->port should be %NULL, and the per-port structures should be registered
2716 * using uart_add_one_port() after this call has succeeded.
2717 *
2718 * Locking: none, Interrupts: enabled
2719 */
uart_register_driver(struct uart_driver * drv)2720 int uart_register_driver(struct uart_driver *drv)
2721 {
2722 struct tty_driver *normal;
2723 int i, retval = -ENOMEM;
2724
2725 BUG_ON(drv->state);
2726
2727 /*
2728 * Maybe we should be using a slab cache for this, especially if
2729 * we have a large number of ports to handle.
2730 */
2731 drv->state = kcalloc(drv->nr, sizeof(struct uart_state), GFP_KERNEL);
2732 if (!drv->state)
2733 goto out;
2734
2735 normal = tty_alloc_driver(drv->nr, TTY_DRIVER_REAL_RAW |
2736 TTY_DRIVER_DYNAMIC_DEV);
2737 if (IS_ERR(normal)) {
2738 retval = PTR_ERR(normal);
2739 goto out_kfree;
2740 }
2741
2742 drv->tty_driver = normal;
2743
2744 normal->driver_name = drv->driver_name;
2745 normal->name = drv->dev_name;
2746 normal->major = drv->major;
2747 normal->minor_start = drv->minor;
2748 normal->type = TTY_DRIVER_TYPE_SERIAL;
2749 normal->subtype = SERIAL_TYPE_NORMAL;
2750 normal->init_termios = tty_std_termios;
2751 normal->init_termios.c_cflag = B9600 | CS8 | CREAD | HUPCL | CLOCAL;
2752 normal->init_termios.c_ispeed = normal->init_termios.c_ospeed = 9600;
2753 normal->driver_state = drv;
2754 tty_set_operations(normal, &uart_ops);
2755
2756 /*
2757 * Initialise the UART state(s).
2758 */
2759 for (i = 0; i < drv->nr; i++) {
2760 struct uart_state *state = drv->state + i;
2761 struct tty_port *port = &state->port;
2762
2763 tty_port_init(port);
2764 port->ops = &uart_port_ops;
2765 }
2766
2767 retval = tty_register_driver(normal);
2768 if (retval >= 0)
2769 return retval;
2770
2771 for (i = 0; i < drv->nr; i++)
2772 tty_port_destroy(&drv->state[i].port);
2773 tty_driver_kref_put(normal);
2774 out_kfree:
2775 kfree(drv->state);
2776 out:
2777 return retval;
2778 }
2779 EXPORT_SYMBOL(uart_register_driver);
2780
2781 /**
2782 * uart_unregister_driver - remove a driver from the uart core layer
2783 * @drv: low level driver structure
2784 *
2785 * Remove all references to a driver from the core driver. The low level
2786 * driver must have removed all its ports via the uart_remove_one_port() if it
2787 * registered them with uart_add_one_port(). (I.e. @drv->port is %NULL.)
2788 *
2789 * Locking: none, Interrupts: enabled
2790 */
uart_unregister_driver(struct uart_driver * drv)2791 void uart_unregister_driver(struct uart_driver *drv)
2792 {
2793 struct tty_driver *p = drv->tty_driver;
2794 unsigned int i;
2795
2796 tty_unregister_driver(p);
2797 tty_driver_kref_put(p);
2798 for (i = 0; i < drv->nr; i++)
2799 tty_port_destroy(&drv->state[i].port);
2800 kfree(drv->state);
2801 drv->state = NULL;
2802 drv->tty_driver = NULL;
2803 }
2804 EXPORT_SYMBOL(uart_unregister_driver);
2805
uart_console_device(struct console * co,int * index)2806 struct tty_driver *uart_console_device(struct console *co, int *index)
2807 {
2808 struct uart_driver *p = co->data;
2809 *index = co->index;
2810 return p->tty_driver;
2811 }
2812 EXPORT_SYMBOL_GPL(uart_console_device);
2813
uartclk_show(struct device * dev,struct device_attribute * attr,char * buf)2814 static ssize_t uartclk_show(struct device *dev,
2815 struct device_attribute *attr, char *buf)
2816 {
2817 struct serial_struct tmp;
2818 struct tty_port *port = dev_get_drvdata(dev);
2819
2820 uart_get_info(port, &tmp);
2821 return sprintf(buf, "%d\n", tmp.baud_base * 16);
2822 }
2823
type_show(struct device * dev,struct device_attribute * attr,char * buf)2824 static ssize_t type_show(struct device *dev,
2825 struct device_attribute *attr, char *buf)
2826 {
2827 struct serial_struct tmp;
2828 struct tty_port *port = dev_get_drvdata(dev);
2829
2830 uart_get_info(port, &tmp);
2831 return sprintf(buf, "%d\n", tmp.type);
2832 }
2833
line_show(struct device * dev,struct device_attribute * attr,char * buf)2834 static ssize_t line_show(struct device *dev,
2835 struct device_attribute *attr, char *buf)
2836 {
2837 struct serial_struct tmp;
2838 struct tty_port *port = dev_get_drvdata(dev);
2839
2840 uart_get_info(port, &tmp);
2841 return sprintf(buf, "%d\n", tmp.line);
2842 }
2843
port_show(struct device * dev,struct device_attribute * attr,char * buf)2844 static ssize_t port_show(struct device *dev,
2845 struct device_attribute *attr, char *buf)
2846 {
2847 struct serial_struct tmp;
2848 struct tty_port *port = dev_get_drvdata(dev);
2849 unsigned long ioaddr;
2850
2851 uart_get_info(port, &tmp);
2852 ioaddr = tmp.port;
2853 if (HIGH_BITS_OFFSET)
2854 ioaddr |= (unsigned long)tmp.port_high << HIGH_BITS_OFFSET;
2855 return sprintf(buf, "0x%lX\n", ioaddr);
2856 }
2857
irq_show(struct device * dev,struct device_attribute * attr,char * buf)2858 static ssize_t irq_show(struct device *dev,
2859 struct device_attribute *attr, char *buf)
2860 {
2861 struct serial_struct tmp;
2862 struct tty_port *port = dev_get_drvdata(dev);
2863
2864 uart_get_info(port, &tmp);
2865 return sprintf(buf, "%d\n", tmp.irq);
2866 }
2867
flags_show(struct device * dev,struct device_attribute * attr,char * buf)2868 static ssize_t flags_show(struct device *dev,
2869 struct device_attribute *attr, char *buf)
2870 {
2871 struct serial_struct tmp;
2872 struct tty_port *port = dev_get_drvdata(dev);
2873
2874 uart_get_info(port, &tmp);
2875 return sprintf(buf, "0x%X\n", tmp.flags);
2876 }
2877
xmit_fifo_size_show(struct device * dev,struct device_attribute * attr,char * buf)2878 static ssize_t xmit_fifo_size_show(struct device *dev,
2879 struct device_attribute *attr, char *buf)
2880 {
2881 struct serial_struct tmp;
2882 struct tty_port *port = dev_get_drvdata(dev);
2883
2884 uart_get_info(port, &tmp);
2885 return sprintf(buf, "%d\n", tmp.xmit_fifo_size);
2886 }
2887
close_delay_show(struct device * dev,struct device_attribute * attr,char * buf)2888 static ssize_t close_delay_show(struct device *dev,
2889 struct device_attribute *attr, char *buf)
2890 {
2891 struct serial_struct tmp;
2892 struct tty_port *port = dev_get_drvdata(dev);
2893
2894 uart_get_info(port, &tmp);
2895 return sprintf(buf, "%d\n", tmp.close_delay);
2896 }
2897
closing_wait_show(struct device * dev,struct device_attribute * attr,char * buf)2898 static ssize_t closing_wait_show(struct device *dev,
2899 struct device_attribute *attr, char *buf)
2900 {
2901 struct serial_struct tmp;
2902 struct tty_port *port = dev_get_drvdata(dev);
2903
2904 uart_get_info(port, &tmp);
2905 return sprintf(buf, "%d\n", tmp.closing_wait);
2906 }
2907
custom_divisor_show(struct device * dev,struct device_attribute * attr,char * buf)2908 static ssize_t custom_divisor_show(struct device *dev,
2909 struct device_attribute *attr, char *buf)
2910 {
2911 struct serial_struct tmp;
2912 struct tty_port *port = dev_get_drvdata(dev);
2913
2914 uart_get_info(port, &tmp);
2915 return sprintf(buf, "%d\n", tmp.custom_divisor);
2916 }
2917
io_type_show(struct device * dev,struct device_attribute * attr,char * buf)2918 static ssize_t io_type_show(struct device *dev,
2919 struct device_attribute *attr, char *buf)
2920 {
2921 struct serial_struct tmp;
2922 struct tty_port *port = dev_get_drvdata(dev);
2923
2924 uart_get_info(port, &tmp);
2925 return sprintf(buf, "%d\n", tmp.io_type);
2926 }
2927
iomem_base_show(struct device * dev,struct device_attribute * attr,char * buf)2928 static ssize_t iomem_base_show(struct device *dev,
2929 struct device_attribute *attr, char *buf)
2930 {
2931 struct serial_struct tmp;
2932 struct tty_port *port = dev_get_drvdata(dev);
2933
2934 uart_get_info(port, &tmp);
2935 return sprintf(buf, "0x%lX\n", (unsigned long)tmp.iomem_base);
2936 }
2937
iomem_reg_shift_show(struct device * dev,struct device_attribute * attr,char * buf)2938 static ssize_t iomem_reg_shift_show(struct device *dev,
2939 struct device_attribute *attr, char *buf)
2940 {
2941 struct serial_struct tmp;
2942 struct tty_port *port = dev_get_drvdata(dev);
2943
2944 uart_get_info(port, &tmp);
2945 return sprintf(buf, "%d\n", tmp.iomem_reg_shift);
2946 }
2947
console_show(struct device * dev,struct device_attribute * attr,char * buf)2948 static ssize_t console_show(struct device *dev,
2949 struct device_attribute *attr, char *buf)
2950 {
2951 struct tty_port *port = dev_get_drvdata(dev);
2952 struct uart_state *state = container_of(port, struct uart_state, port);
2953 struct uart_port *uport;
2954 bool console = false;
2955
2956 mutex_lock(&port->mutex);
2957 uport = uart_port_check(state);
2958 if (uport)
2959 console = uart_console_enabled(uport);
2960 mutex_unlock(&port->mutex);
2961
2962 return sprintf(buf, "%c\n", console ? 'Y' : 'N');
2963 }
2964
console_store(struct device * dev,struct device_attribute * attr,const char * buf,size_t count)2965 static ssize_t console_store(struct device *dev,
2966 struct device_attribute *attr, const char *buf, size_t count)
2967 {
2968 struct tty_port *port = dev_get_drvdata(dev);
2969 struct uart_state *state = container_of(port, struct uart_state, port);
2970 struct uart_port *uport;
2971 bool oldconsole, newconsole;
2972 int ret;
2973
2974 ret = kstrtobool(buf, &newconsole);
2975 if (ret)
2976 return ret;
2977
2978 mutex_lock(&port->mutex);
2979 uport = uart_port_check(state);
2980 if (uport) {
2981 oldconsole = uart_console_enabled(uport);
2982 if (oldconsole && !newconsole) {
2983 ret = unregister_console(uport->cons);
2984 } else if (!oldconsole && newconsole) {
2985 if (uart_console(uport)) {
2986 uport->console_reinit = 1;
2987 register_console(uport->cons);
2988 } else {
2989 ret = -ENOENT;
2990 }
2991 }
2992 } else {
2993 ret = -ENXIO;
2994 }
2995 mutex_unlock(&port->mutex);
2996
2997 return ret < 0 ? ret : count;
2998 }
2999
3000 static DEVICE_ATTR_RO(uartclk);
3001 static DEVICE_ATTR_RO(type);
3002 static DEVICE_ATTR_RO(line);
3003 static DEVICE_ATTR_RO(port);
3004 static DEVICE_ATTR_RO(irq);
3005 static DEVICE_ATTR_RO(flags);
3006 static DEVICE_ATTR_RO(xmit_fifo_size);
3007 static DEVICE_ATTR_RO(close_delay);
3008 static DEVICE_ATTR_RO(closing_wait);
3009 static DEVICE_ATTR_RO(custom_divisor);
3010 static DEVICE_ATTR_RO(io_type);
3011 static DEVICE_ATTR_RO(iomem_base);
3012 static DEVICE_ATTR_RO(iomem_reg_shift);
3013 static DEVICE_ATTR_RW(console);
3014
3015 static struct attribute *tty_dev_attrs[] = {
3016 &dev_attr_uartclk.attr,
3017 &dev_attr_type.attr,
3018 &dev_attr_line.attr,
3019 &dev_attr_port.attr,
3020 &dev_attr_irq.attr,
3021 &dev_attr_flags.attr,
3022 &dev_attr_xmit_fifo_size.attr,
3023 &dev_attr_close_delay.attr,
3024 &dev_attr_closing_wait.attr,
3025 &dev_attr_custom_divisor.attr,
3026 &dev_attr_io_type.attr,
3027 &dev_attr_iomem_base.attr,
3028 &dev_attr_iomem_reg_shift.attr,
3029 &dev_attr_console.attr,
3030 NULL
3031 };
3032
3033 static const struct attribute_group tty_dev_attr_group = {
3034 .attrs = tty_dev_attrs,
3035 };
3036
3037 /**
3038 * uart_add_one_port - attach a driver-defined port structure
3039 * @drv: pointer to the uart low level driver structure for this port
3040 * @uport: uart port structure to use for this port.
3041 *
3042 * Context: task context, might sleep
3043 *
3044 * This allows the driver @drv to register its own uart_port structure with the
3045 * core driver. The main purpose is to allow the low level uart drivers to
3046 * expand uart_port, rather than having yet more levels of structures.
3047 */
uart_add_one_port(struct uart_driver * drv,struct uart_port * uport)3048 int uart_add_one_port(struct uart_driver *drv, struct uart_port *uport)
3049 {
3050 struct uart_state *state;
3051 struct tty_port *port;
3052 int ret = 0;
3053 struct device *tty_dev;
3054 int num_groups;
3055
3056 if (uport->line >= drv->nr)
3057 return -EINVAL;
3058
3059 state = drv->state + uport->line;
3060 port = &state->port;
3061
3062 mutex_lock(&port_mutex);
3063 mutex_lock(&port->mutex);
3064 if (state->uart_port) {
3065 ret = -EINVAL;
3066 goto out;
3067 }
3068
3069 /* Link the port to the driver state table and vice versa */
3070 atomic_set(&state->refcount, 1);
3071 init_waitqueue_head(&state->remove_wait);
3072 state->uart_port = uport;
3073 uport->state = state;
3074
3075 state->pm_state = UART_PM_STATE_UNDEFINED;
3076 uport->cons = drv->cons;
3077 uport->minor = drv->tty_driver->minor_start + uport->line;
3078 uport->name = kasprintf(GFP_KERNEL, "%s%d", drv->dev_name,
3079 drv->tty_driver->name_base + uport->line);
3080 if (!uport->name) {
3081 ret = -ENOMEM;
3082 goto out;
3083 }
3084
3085 /*
3086 * If this port is in use as a console then the spinlock is already
3087 * initialised.
3088 */
3089 if (!uart_console_enabled(uport))
3090 uart_port_spin_lock_init(uport);
3091
3092 if (uport->cons && uport->dev)
3093 of_console_check(uport->dev->of_node, uport->cons->name, uport->line);
3094
3095 tty_port_link_device(port, drv->tty_driver, uport->line);
3096 uart_configure_port(drv, state, uport);
3097
3098 port->console = uart_console(uport);
3099
3100 num_groups = 2;
3101 if (uport->attr_group)
3102 num_groups++;
3103
3104 uport->tty_groups = kcalloc(num_groups, sizeof(*uport->tty_groups),
3105 GFP_KERNEL);
3106 if (!uport->tty_groups) {
3107 ret = -ENOMEM;
3108 goto out;
3109 }
3110 uport->tty_groups[0] = &tty_dev_attr_group;
3111 if (uport->attr_group)
3112 uport->tty_groups[1] = uport->attr_group;
3113
3114 /*
3115 * Register the port whether it's detected or not. This allows
3116 * setserial to be used to alter this port's parameters.
3117 */
3118 tty_dev = tty_port_register_device_attr_serdev(port, drv->tty_driver,
3119 uport->line, uport->dev, port, uport->tty_groups);
3120 if (!IS_ERR(tty_dev)) {
3121 device_set_wakeup_capable(tty_dev, 1);
3122 } else {
3123 dev_err(uport->dev, "Cannot register tty device on line %d\n",
3124 uport->line);
3125 }
3126
3127 /*
3128 * Ensure UPF_DEAD is not set.
3129 */
3130 uport->flags &= ~UPF_DEAD;
3131
3132 out:
3133 mutex_unlock(&port->mutex);
3134 mutex_unlock(&port_mutex);
3135
3136 return ret;
3137 }
3138 EXPORT_SYMBOL(uart_add_one_port);
3139
3140 /**
3141 * uart_remove_one_port - detach a driver defined port structure
3142 * @drv: pointer to the uart low level driver structure for this port
3143 * @uport: uart port structure for this port
3144 *
3145 * Context: task context, might sleep
3146 *
3147 * This unhooks (and hangs up) the specified port structure from the core
3148 * driver. No further calls will be made to the low-level code for this port.
3149 */
uart_remove_one_port(struct uart_driver * drv,struct uart_port * uport)3150 int uart_remove_one_port(struct uart_driver *drv, struct uart_port *uport)
3151 {
3152 struct uart_state *state = drv->state + uport->line;
3153 struct tty_port *port = &state->port;
3154 struct uart_port *uart_port;
3155 struct tty_struct *tty;
3156 int ret = 0;
3157
3158 mutex_lock(&port_mutex);
3159
3160 /*
3161 * Mark the port "dead" - this prevents any opens from
3162 * succeeding while we shut down the port.
3163 */
3164 mutex_lock(&port->mutex);
3165 uart_port = uart_port_check(state);
3166 if (uart_port != uport)
3167 dev_alert(uport->dev, "Removing wrong port: %p != %p\n",
3168 uart_port, uport);
3169
3170 if (!uart_port) {
3171 mutex_unlock(&port->mutex);
3172 ret = -EINVAL;
3173 goto out;
3174 }
3175 uport->flags |= UPF_DEAD;
3176 mutex_unlock(&port->mutex);
3177
3178 /*
3179 * Remove the devices from the tty layer
3180 */
3181 tty_port_unregister_device(port, drv->tty_driver, uport->line);
3182
3183 tty = tty_port_tty_get(port);
3184 if (tty) {
3185 tty_vhangup(port->tty);
3186 tty_kref_put(tty);
3187 }
3188
3189 /*
3190 * If the port is used as a console, unregister it
3191 */
3192 if (uart_console(uport))
3193 unregister_console(uport->cons);
3194
3195 /*
3196 * Free the port IO and memory resources, if any.
3197 */
3198 if (uport->type != PORT_UNKNOWN && uport->ops->release_port)
3199 uport->ops->release_port(uport);
3200 kfree(uport->tty_groups);
3201 kfree(uport->name);
3202
3203 /*
3204 * Indicate that there isn't a port here anymore.
3205 */
3206 uport->type = PORT_UNKNOWN;
3207
3208 mutex_lock(&port->mutex);
3209 WARN_ON(atomic_dec_return(&state->refcount) < 0);
3210 wait_event(state->remove_wait, !atomic_read(&state->refcount));
3211 state->uart_port = NULL;
3212 mutex_unlock(&port->mutex);
3213 out:
3214 mutex_unlock(&port_mutex);
3215
3216 return ret;
3217 }
3218 EXPORT_SYMBOL(uart_remove_one_port);
3219
3220 /**
3221 * uart_match_port - are the two ports equivalent?
3222 * @port1: first port
3223 * @port2: second port
3224 *
3225 * This utility function can be used to determine whether two uart_port
3226 * structures describe the same port.
3227 */
uart_match_port(const struct uart_port * port1,const struct uart_port * port2)3228 bool uart_match_port(const struct uart_port *port1,
3229 const struct uart_port *port2)
3230 {
3231 if (port1->iotype != port2->iotype)
3232 return false;
3233
3234 switch (port1->iotype) {
3235 case UPIO_PORT:
3236 return port1->iobase == port2->iobase;
3237 case UPIO_HUB6:
3238 return port1->iobase == port2->iobase &&
3239 port1->hub6 == port2->hub6;
3240 case UPIO_MEM:
3241 case UPIO_MEM16:
3242 case UPIO_MEM32:
3243 case UPIO_MEM32BE:
3244 case UPIO_AU:
3245 case UPIO_TSI:
3246 return port1->mapbase == port2->mapbase;
3247 }
3248
3249 return false;
3250 }
3251 EXPORT_SYMBOL(uart_match_port);
3252
3253 /**
3254 * uart_handle_dcd_change - handle a change of carrier detect state
3255 * @uport: uart_port structure for the open port
3256 * @status: new carrier detect status, nonzero if active
3257 *
3258 * Caller must hold uport->lock.
3259 */
uart_handle_dcd_change(struct uart_port * uport,unsigned int status)3260 void uart_handle_dcd_change(struct uart_port *uport, unsigned int status)
3261 {
3262 struct tty_port *port = &uport->state->port;
3263 struct tty_struct *tty = port->tty;
3264 struct tty_ldisc *ld;
3265
3266 lockdep_assert_held_once(&uport->lock);
3267
3268 if (tty) {
3269 ld = tty_ldisc_ref(tty);
3270 if (ld) {
3271 if (ld->ops->dcd_change)
3272 ld->ops->dcd_change(tty, status);
3273 tty_ldisc_deref(ld);
3274 }
3275 }
3276
3277 uport->icount.dcd++;
3278
3279 if (uart_dcd_enabled(uport)) {
3280 if (status)
3281 wake_up_interruptible(&port->open_wait);
3282 else if (tty)
3283 tty_hangup(tty);
3284 }
3285 }
3286 EXPORT_SYMBOL_GPL(uart_handle_dcd_change);
3287
3288 /**
3289 * uart_handle_cts_change - handle a change of clear-to-send state
3290 * @uport: uart_port structure for the open port
3291 * @status: new clear to send status, nonzero if active
3292 *
3293 * Caller must hold uport->lock.
3294 */
uart_handle_cts_change(struct uart_port * uport,unsigned int status)3295 void uart_handle_cts_change(struct uart_port *uport, unsigned int status)
3296 {
3297 lockdep_assert_held_once(&uport->lock);
3298
3299 uport->icount.cts++;
3300
3301 if (uart_softcts_mode(uport)) {
3302 if (uport->hw_stopped) {
3303 if (status) {
3304 uport->hw_stopped = 0;
3305 uport->ops->start_tx(uport);
3306 uart_write_wakeup(uport);
3307 }
3308 } else {
3309 if (!status) {
3310 uport->hw_stopped = 1;
3311 uport->ops->stop_tx(uport);
3312 }
3313 }
3314
3315 }
3316 }
3317 EXPORT_SYMBOL_GPL(uart_handle_cts_change);
3318
3319 /**
3320 * uart_insert_char - push a char to the uart layer
3321 *
3322 * User is responsible to call tty_flip_buffer_push when they are done with
3323 * insertion.
3324 *
3325 * @port: corresponding port
3326 * @status: state of the serial port RX buffer (LSR for 8250)
3327 * @overrun: mask of overrun bits in @status
3328 * @ch: character to push
3329 * @flag: flag for the character (see TTY_NORMAL and friends)
3330 */
uart_insert_char(struct uart_port * port,unsigned int status,unsigned int overrun,unsigned int ch,unsigned int flag)3331 void uart_insert_char(struct uart_port *port, unsigned int status,
3332 unsigned int overrun, unsigned int ch, unsigned int flag)
3333 {
3334 struct tty_port *tport = &port->state->port;
3335
3336 if ((status & port->ignore_status_mask & ~overrun) == 0)
3337 if (tty_insert_flip_char(tport, ch, flag) == 0)
3338 ++port->icount.buf_overrun;
3339
3340 /*
3341 * Overrun is special. Since it's reported immediately,
3342 * it doesn't affect the current character.
3343 */
3344 if (status & ~port->ignore_status_mask & overrun)
3345 if (tty_insert_flip_char(tport, 0, TTY_OVERRUN) == 0)
3346 ++port->icount.buf_overrun;
3347 }
3348 EXPORT_SYMBOL_GPL(uart_insert_char);
3349
3350 #ifdef CONFIG_MAGIC_SYSRQ_SERIAL
3351 static const char sysrq_toggle_seq[] = CONFIG_MAGIC_SYSRQ_SERIAL_SEQUENCE;
3352
uart_sysrq_on(struct work_struct * w)3353 static void uart_sysrq_on(struct work_struct *w)
3354 {
3355 int sysrq_toggle_seq_len = strlen(sysrq_toggle_seq);
3356
3357 sysrq_toggle_support(1);
3358 pr_info("SysRq is enabled by magic sequence '%*pE' on serial\n",
3359 sysrq_toggle_seq_len, sysrq_toggle_seq);
3360 }
3361 static DECLARE_WORK(sysrq_enable_work, uart_sysrq_on);
3362
3363 /**
3364 * uart_try_toggle_sysrq - Enables SysRq from serial line
3365 * @port: uart_port structure where char(s) after BREAK met
3366 * @ch: new character in the sequence after received BREAK
3367 *
3368 * Enables magic SysRq when the required sequence is met on port
3369 * (see CONFIG_MAGIC_SYSRQ_SERIAL_SEQUENCE).
3370 *
3371 * Returns: %false if @ch is out of enabling sequence and should be
3372 * handled some other way, %true if @ch was consumed.
3373 */
uart_try_toggle_sysrq(struct uart_port * port,unsigned int ch)3374 bool uart_try_toggle_sysrq(struct uart_port *port, unsigned int ch)
3375 {
3376 int sysrq_toggle_seq_len = strlen(sysrq_toggle_seq);
3377
3378 if (!sysrq_toggle_seq_len)
3379 return false;
3380
3381 BUILD_BUG_ON(ARRAY_SIZE(sysrq_toggle_seq) >= U8_MAX);
3382 if (sysrq_toggle_seq[port->sysrq_seq] != ch) {
3383 port->sysrq_seq = 0;
3384 return false;
3385 }
3386
3387 if (++port->sysrq_seq < sysrq_toggle_seq_len) {
3388 port->sysrq = jiffies + SYSRQ_TIMEOUT;
3389 return true;
3390 }
3391
3392 schedule_work(&sysrq_enable_work);
3393
3394 port->sysrq = 0;
3395 return true;
3396 }
3397 EXPORT_SYMBOL_GPL(uart_try_toggle_sysrq);
3398 #endif
3399
3400 /**
3401 * uart_get_rs485_mode() - retrieve rs485 properties for given uart
3402 * @port: uart device's target port
3403 *
3404 * This function implements the device tree binding described in
3405 * Documentation/devicetree/bindings/serial/rs485.txt.
3406 */
uart_get_rs485_mode(struct uart_port * port)3407 int uart_get_rs485_mode(struct uart_port *port)
3408 {
3409 struct serial_rs485 *rs485conf = &port->rs485;
3410 struct device *dev = port->dev;
3411 u32 rs485_delay[2];
3412 int ret;
3413
3414 ret = device_property_read_u32_array(dev, "rs485-rts-delay",
3415 rs485_delay, 2);
3416 if (!ret) {
3417 rs485conf->delay_rts_before_send = rs485_delay[0];
3418 rs485conf->delay_rts_after_send = rs485_delay[1];
3419 } else {
3420 rs485conf->delay_rts_before_send = 0;
3421 rs485conf->delay_rts_after_send = 0;
3422 }
3423
3424 uart_sanitize_serial_rs485_delays(port, rs485conf);
3425
3426 /*
3427 * Clear full-duplex and enabled flags, set RTS polarity to active high
3428 * to get to a defined state with the following properties:
3429 */
3430 rs485conf->flags &= ~(SER_RS485_RX_DURING_TX | SER_RS485_ENABLED |
3431 SER_RS485_TERMINATE_BUS |
3432 SER_RS485_RTS_AFTER_SEND);
3433 rs485conf->flags |= SER_RS485_RTS_ON_SEND;
3434
3435 if (device_property_read_bool(dev, "rs485-rx-during-tx"))
3436 rs485conf->flags |= SER_RS485_RX_DURING_TX;
3437
3438 if (device_property_read_bool(dev, "linux,rs485-enabled-at-boot-time"))
3439 rs485conf->flags |= SER_RS485_ENABLED;
3440
3441 if (device_property_read_bool(dev, "rs485-rts-active-low")) {
3442 rs485conf->flags &= ~SER_RS485_RTS_ON_SEND;
3443 rs485conf->flags |= SER_RS485_RTS_AFTER_SEND;
3444 }
3445
3446 /*
3447 * Disabling termination by default is the safe choice: Else if many
3448 * bus participants enable it, no communication is possible at all.
3449 * Works fine for short cables and users may enable for longer cables.
3450 */
3451 port->rs485_term_gpio = devm_gpiod_get_optional(dev, "rs485-term",
3452 GPIOD_OUT_LOW);
3453 if (IS_ERR(port->rs485_term_gpio)) {
3454 ret = PTR_ERR(port->rs485_term_gpio);
3455 port->rs485_term_gpio = NULL;
3456 return dev_err_probe(dev, ret, "Cannot get rs485-term-gpios\n");
3457 }
3458 if (port->rs485_term_gpio)
3459 port->rs485_supported.flags |= SER_RS485_TERMINATE_BUS;
3460
3461 return 0;
3462 }
3463 EXPORT_SYMBOL_GPL(uart_get_rs485_mode);
3464
3465 /* Compile-time assertions for serial_rs485 layout */
3466 static_assert(offsetof(struct serial_rs485, padding) ==
3467 (offsetof(struct serial_rs485, delay_rts_after_send) + sizeof(__u32)));
3468 static_assert(offsetof(struct serial_rs485, padding1) ==
3469 offsetof(struct serial_rs485, padding[1]));
3470 static_assert((offsetof(struct serial_rs485, padding[4]) + sizeof(__u32)) ==
3471 sizeof(struct serial_rs485));
3472
3473 MODULE_DESCRIPTION("Serial driver core");
3474 MODULE_LICENSE("GPL");
3475