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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/of.h>
18#include <linux/proc_fs.h>
19#include <linux/seq_file.h>
20#include <linux/device.h>
21#include <linux/serial.h> /* for serial_state and serial_icounter_struct */
22#include <linux/serial_core.h>
23#include <linux/delay.h>
24#include <linux/mutex.h>
25
26#include <linux/irq.h>
27#include <linux/uaccess.h>
28
29/*
30 * This is used to lock changes in serial line configuration.
31 */
32static DEFINE_MUTEX(port_mutex);
33
34/*
35 * lockdep: port->lock is initialized in two places, but we
36 * want only one lock-class:
37 */
38static struct lock_class_key port_lock_key;
39
40#define HIGH_BITS_OFFSET ((sizeof(long)-sizeof(int))*8)
41
42static void uart_change_speed(struct tty_struct *tty, struct uart_state *state,
43 struct ktermios *old_termios);
44static void uart_wait_until_sent(struct tty_struct *tty, int timeout);
45static void uart_change_pm(struct uart_state *state,
46 enum uart_pm_state pm_state);
47
48static void uart_port_shutdown(struct tty_port *port);
49
50static int uart_dcd_enabled(struct uart_port *uport)
51{
52 return !!(uport->status & UPSTAT_DCD_ENABLE);
53}
54
55static inline struct uart_port *uart_port_ref(struct uart_state *state)
56{
57 if (atomic_add_unless(&state->refcount, 1, 0))
58 return state->uart_port;
59 return NULL;
60}
61
62static inline void uart_port_deref(struct uart_port *uport)
63{
64 if (atomic_dec_and_test(&uport->state->refcount))
65 wake_up(&uport->state->remove_wait);
66}
67
68#define uart_port_lock(state, flags) \
69 ({ \
70 struct uart_port *__uport = uart_port_ref(state); \
71 if (__uport) \
72 spin_lock_irqsave(&__uport->lock, flags); \
73 __uport; \
74 })
75
76#define uart_port_unlock(uport, flags) \
77 ({ \
78 struct uart_port *__uport = uport; \
79 if (__uport) { \
80 spin_unlock_irqrestore(&__uport->lock, flags); \
81 uart_port_deref(__uport); \
82 } \
83 })
84
85static inline struct uart_port *uart_port_check(struct uart_state *state)
86{
87 lockdep_assert_held(&state->port.mutex);
88 return state->uart_port;
89}
90
91/*
92 * This routine is used by the interrupt handler to schedule processing in
93 * the software interrupt portion of the driver.
94 */
95void uart_write_wakeup(struct uart_port *port)
96{
97 struct uart_state *state = port->state;
98 /*
99 * This means you called this function _after_ the port was
100 * closed. No cookie for you.
101 */
102 BUG_ON(!state);
103 tty_port_tty_wakeup(&state->port);
104}
105
106static void uart_stop(struct tty_struct *tty)
107{
108 struct uart_state *state = tty->driver_data;
109 struct uart_port *port;
110 unsigned long flags;
111
112 port = uart_port_lock(state, flags);
113 if (port)
114 port->ops->stop_tx(port);
115 uart_port_unlock(port, flags);
116}
117
118static void __uart_start(struct tty_struct *tty)
119{
120 struct uart_state *state = tty->driver_data;
121 struct uart_port *port = state->uart_port;
122
123 if (port && !uart_tx_stopped(port))
124 port->ops->start_tx(port);
125}
126
127static void uart_start(struct tty_struct *tty)
128{
129 struct uart_state *state = tty->driver_data;
130 struct uart_port *port;
131 unsigned long flags;
132
133 port = uart_port_lock(state, flags);
134 __uart_start(tty);
135 uart_port_unlock(port, flags);
136}
137
138static void
139uart_update_mctrl(struct uart_port *port, unsigned int set, unsigned int clear)
140{
141 unsigned long flags;
142 unsigned int old;
143
144 spin_lock_irqsave(&port->lock, flags);
145 old = port->mctrl;
146 port->mctrl = (old & ~clear) | set;
147 if (old != port->mctrl)
148 port->ops->set_mctrl(port, port->mctrl);
149 spin_unlock_irqrestore(&port->lock, flags);
150}
151
152#define uart_set_mctrl(port, set) uart_update_mctrl(port, set, 0)
153#define uart_clear_mctrl(port, clear) uart_update_mctrl(port, 0, clear)
154
155static void uart_port_dtr_rts(struct uart_port *uport, int raise)
156{
157 int rs485_on = uport->rs485_config &&
158 (uport->rs485.flags & SER_RS485_ENABLED);
159 int RTS_after_send = !!(uport->rs485.flags & SER_RS485_RTS_AFTER_SEND);
160
161 if (raise) {
162 if (rs485_on && !RTS_after_send) {
163 uart_set_mctrl(uport, TIOCM_DTR);
164 uart_clear_mctrl(uport, TIOCM_RTS);
165 } else {
166 uart_set_mctrl(uport, TIOCM_DTR | TIOCM_RTS);
167 }
168 } else {
169 unsigned int clear = TIOCM_DTR;
170
171 clear |= (!rs485_on || !RTS_after_send) ? TIOCM_RTS : 0;
172 uart_clear_mctrl(uport, clear);
173 }
174}
175
176/*
177 * Startup the port. This will be called once per open. All calls
178 * will be serialised by the per-port mutex.
179 */
180static int uart_port_startup(struct tty_struct *tty, struct uart_state *state,
181 int init_hw)
182{
183 struct uart_port *uport = uart_port_check(state);
184 unsigned long page;
185 int retval = 0;
186
187 if (uport->type == PORT_UNKNOWN)
188 return 1;
189
190 /*
191 * Make sure the device is in D0 state.
192 */
193 uart_change_pm(state, UART_PM_STATE_ON);
194
195 /*
196 * Initialise and allocate the transmit and temporary
197 * buffer.
198 */
199 if (!state->xmit.buf) {
200 /* This is protected by the per port mutex */
201 page = get_zeroed_page(GFP_KERNEL);
202 if (!page)
203 return -ENOMEM;
204
205 state->xmit.buf = (unsigned char *) page;
206 uart_circ_clear(&state->xmit);
207 }
208
209 retval = uport->ops->startup(uport);
210 if (retval == 0) {
211 if (uart_console(uport) && uport->cons->cflag) {
212 tty->termios.c_cflag = uport->cons->cflag;
213 uport->cons->cflag = 0;
214 }
215 /*
216 * Initialise the hardware port settings.
217 */
218 uart_change_speed(tty, state, NULL);
219
220 /*
221 * Setup the RTS and DTR signals once the
222 * port is open and ready to respond.
223 */
224 if (init_hw && C_BAUD(tty))
225 uart_port_dtr_rts(uport, 1);
226 }
227
228 /*
229 * This is to allow setserial on this port. People may want to set
230 * port/irq/type and then reconfigure the port properly if it failed
231 * now.
232 */
233 if (retval && capable(CAP_SYS_ADMIN))
234 return 1;
235
236 return retval;
237}
238
239static int uart_startup(struct tty_struct *tty, struct uart_state *state,
240 int init_hw)
241{
242 struct tty_port *port = &state->port;
243 int retval;
244
245 if (tty_port_initialized(port))
246 return 0;
247
248 retval = uart_port_startup(tty, state, init_hw);
249 if (retval)
250 set_bit(TTY_IO_ERROR, &tty->flags);
251
252 return retval;
253}
254
255/*
256 * This routine will shutdown a serial port; interrupts are disabled, and
257 * DTR is dropped if the hangup on close termio flag is on. Calls to
258 * uart_shutdown are serialised by the per-port semaphore.
259 *
260 * uport == NULL if uart_port has already been removed
261 */
262static void uart_shutdown(struct tty_struct *tty, struct uart_state *state)
263{
264 struct uart_port *uport = uart_port_check(state);
265 struct tty_port *port = &state->port;
266
267 /*
268 * Set the TTY IO error marker
269 */
270 if (tty)
271 set_bit(TTY_IO_ERROR, &tty->flags);
272
273 if (tty_port_initialized(port)) {
274 tty_port_set_initialized(port, 0);
275
276 /*
277 * Turn off DTR and RTS early.
278 */
279 if (uport && uart_console(uport) && tty)
280 uport->cons->cflag = tty->termios.c_cflag;
281
282 if (!tty || C_HUPCL(tty))
283 uart_port_dtr_rts(uport, 0);
284
285 uart_port_shutdown(port);
286 }
287
288 /*
289 * It's possible for shutdown to be called after suspend if we get
290 * a DCD drop (hangup) at just the right time. Clear suspended bit so
291 * we don't try to resume a port that has been shutdown.
292 */
293 tty_port_set_suspended(port, 0);
294
295 /*
296 * Free the transmit buffer page.
297 */
298 if (state->xmit.buf) {
299 free_page((unsigned long)state->xmit.buf);
300 state->xmit.buf = NULL;
301 }
302}
303
304/**
305 * uart_update_timeout - update per-port FIFO timeout.
306 * @port: uart_port structure describing the port
307 * @cflag: termios cflag value
308 * @baud: speed of the port
309 *
310 * Set the port FIFO timeout value. The @cflag value should
311 * reflect the actual hardware settings.
312 */
313void
314uart_update_timeout(struct uart_port *port, unsigned int cflag,
315 unsigned int baud)
316{
317 unsigned int bits;
318
319 /* byte size and parity */
320 switch (cflag & CSIZE) {
321 case CS5:
322 bits = 7;
323 break;
324 case CS6:
325 bits = 8;
326 break;
327 case CS7:
328 bits = 9;
329 break;
330 default:
331 bits = 10;
332 break; /* CS8 */
333 }
334
335 if (cflag & CSTOPB)
336 bits++;
337 if (cflag & PARENB)
338 bits++;
339
340 /*
341 * The total number of bits to be transmitted in the fifo.
342 */
343 bits = bits * port->fifosize;
344
345 /*
346 * Figure the timeout to send the above number of bits.
347 * Add .02 seconds of slop
348 */
349 port->timeout = (HZ * bits) / baud + HZ/50;
350}
351
352EXPORT_SYMBOL(uart_update_timeout);
353
354/**
355 * uart_get_baud_rate - return baud rate for a particular port
356 * @port: uart_port structure describing the port in question.
357 * @termios: desired termios settings.
358 * @old: old termios (or NULL)
359 * @min: minimum acceptable baud rate
360 * @max: maximum acceptable baud rate
361 *
362 * Decode the termios structure into a numeric baud rate,
363 * taking account of the magic 38400 baud rate (with spd_*
364 * flags), and mapping the %B0 rate to 9600 baud.
365 *
366 * If the new baud rate is invalid, try the old termios setting.
367 * If it's still invalid, we try 9600 baud.
368 *
369 * Update the @termios structure to reflect the baud rate
370 * we're actually going to be using. Don't do this for the case
371 * where B0 is requested ("hang up").
372 */
373unsigned int
374uart_get_baud_rate(struct uart_port *port, struct ktermios *termios,
375 struct ktermios *old, unsigned int min, unsigned int max)
376{
377 unsigned int try;
378 unsigned int baud;
379 unsigned int altbaud;
380 int hung_up = 0;
381 upf_t flags = port->flags & UPF_SPD_MASK;
382
383 switch (flags) {
384 case UPF_SPD_HI:
385 altbaud = 57600;
386 break;
387 case UPF_SPD_VHI:
388 altbaud = 115200;
389 break;
390 case UPF_SPD_SHI:
391 altbaud = 230400;
392 break;
393 case UPF_SPD_WARP:
394 altbaud = 460800;
395 break;
396 default:
397 altbaud = 38400;
398 break;
399 }
400
401 for (try = 0; try < 2; try++) {
402 baud = tty_termios_baud_rate(termios);
403
404 /*
405 * The spd_hi, spd_vhi, spd_shi, spd_warp kludge...
406 * Die! Die! Die!
407 */
408 if (try == 0 && baud == 38400)
409 baud = altbaud;
410
411 /*
412 * Special case: B0 rate.
413 */
414 if (baud == 0) {
415 hung_up = 1;
416 baud = 9600;
417 }
418
419 if (baud >= min && baud <= max)
420 return baud;
421
422 /*
423 * Oops, the quotient was zero. Try again with
424 * the old baud rate if possible.
425 */
426 termios->c_cflag &= ~CBAUD;
427 if (old) {
428 baud = tty_termios_baud_rate(old);
429 if (!hung_up)
430 tty_termios_encode_baud_rate(termios,
431 baud, baud);
432 old = NULL;
433 continue;
434 }
435
436 /*
437 * As a last resort, if the range cannot be met then clip to
438 * the nearest chip supported rate.
439 */
440 if (!hung_up) {
441 if (baud <= min)
442 tty_termios_encode_baud_rate(termios,
443 min + 1, min + 1);
444 else
445 tty_termios_encode_baud_rate(termios,
446 max - 1, max - 1);
447 }
448 }
449 /* Should never happen */
450 WARN_ON(1);
451 return 0;
452}
453
454EXPORT_SYMBOL(uart_get_baud_rate);
455
456/**
457 * uart_get_divisor - return uart clock divisor
458 * @port: uart_port structure describing the port.
459 * @baud: desired baud rate
460 *
461 * Calculate the uart clock divisor for the port.
462 */
463unsigned int
464uart_get_divisor(struct uart_port *port, unsigned int baud)
465{
466 unsigned int quot;
467
468 /*
469 * Old custom speed handling.
470 */
471 if (baud == 38400 && (port->flags & UPF_SPD_MASK) == UPF_SPD_CUST)
472 quot = port->custom_divisor;
473 else
474 quot = DIV_ROUND_CLOSEST(port->uartclk, 16 * baud);
475
476 return quot;
477}
478
479EXPORT_SYMBOL(uart_get_divisor);
480
481/* Caller holds port mutex */
482static void uart_change_speed(struct tty_struct *tty, struct uart_state *state,
483 struct ktermios *old_termios)
484{
485 struct uart_port *uport = uart_port_check(state);
486 struct ktermios *termios;
487 int hw_stopped;
488
489 /*
490 * If we have no tty, termios, or the port does not exist,
491 * then we can't set the parameters for this port.
492 */
493 if (!tty || uport->type == PORT_UNKNOWN)
494 return;
495
496 termios = &tty->termios;
497 uport->ops->set_termios(uport, termios, old_termios);
498
499 /*
500 * Set modem status enables based on termios cflag
501 */
502 spin_lock_irq(&uport->lock);
503 if (termios->c_cflag & CRTSCTS)
504 uport->status |= UPSTAT_CTS_ENABLE;
505 else
506 uport->status &= ~UPSTAT_CTS_ENABLE;
507
508 if (termios->c_cflag & CLOCAL)
509 uport->status &= ~UPSTAT_DCD_ENABLE;
510 else
511 uport->status |= UPSTAT_DCD_ENABLE;
512
513 /* reset sw-assisted CTS flow control based on (possibly) new mode */
514 hw_stopped = uport->hw_stopped;
515 uport->hw_stopped = uart_softcts_mode(uport) &&
516 !(uport->ops->get_mctrl(uport) & TIOCM_CTS);
517 if (uport->hw_stopped) {
518 if (!hw_stopped)
519 uport->ops->stop_tx(uport);
520 } else {
521 if (hw_stopped)
522 __uart_start(tty);
523 }
524 spin_unlock_irq(&uport->lock);
525}
526
527static int uart_put_char(struct tty_struct *tty, unsigned char c)
528{
529 struct uart_state *state = tty->driver_data;
530 struct uart_port *port;
531 struct circ_buf *circ;
532 unsigned long flags;
533 int ret = 0;
534
535 circ = &state->xmit;
536 if (!circ->buf)
537 return 0;
538
539 port = uart_port_lock(state, flags);
540 if (port && uart_circ_chars_free(circ) != 0) {
541 circ->buf[circ->head] = c;
542 circ->head = (circ->head + 1) & (UART_XMIT_SIZE - 1);
543 ret = 1;
544 }
545 uart_port_unlock(port, flags);
546 return ret;
547}
548
549static void uart_flush_chars(struct tty_struct *tty)
550{
551 uart_start(tty);
552}
553
554static int uart_write(struct tty_struct *tty,
555 const unsigned char *buf, int count)
556{
557 struct uart_state *state = tty->driver_data;
558 struct uart_port *port;
559 struct circ_buf *circ;
560 unsigned long flags;
561 int c, ret = 0;
562
563 /*
564 * This means you called this function _after_ the port was
565 * closed. No cookie for you.
566 */
567 if (!state) {
568 WARN_ON(1);
569 return -EL3HLT;
570 }
571
572 circ = &state->xmit;
573 if (!circ->buf)
574 return 0;
575
576 port = uart_port_lock(state, flags);
577 while (port) {
578 c = CIRC_SPACE_TO_END(circ->head, circ->tail, UART_XMIT_SIZE);
579 if (count < c)
580 c = count;
581 if (c <= 0)
582 break;
583 memcpy(circ->buf + circ->head, buf, c);
584 circ->head = (circ->head + c) & (UART_XMIT_SIZE - 1);
585 buf += c;
586 count -= c;
587 ret += c;
588 }
589
590 __uart_start(tty);
591 uart_port_unlock(port, flags);
592 return ret;
593}
594
595static int uart_write_room(struct tty_struct *tty)
596{
597 struct uart_state *state = tty->driver_data;
598 struct uart_port *port;
599 unsigned long flags;
600 int ret;
601
602 port = uart_port_lock(state, flags);
603 ret = uart_circ_chars_free(&state->xmit);
604 uart_port_unlock(port, flags);
605 return ret;
606}
607
608static int uart_chars_in_buffer(struct tty_struct *tty)
609{
610 struct uart_state *state = tty->driver_data;
611 struct uart_port *port;
612 unsigned long flags;
613 int ret;
614
615 port = uart_port_lock(state, flags);
616 ret = uart_circ_chars_pending(&state->xmit);
617 uart_port_unlock(port, flags);
618 return ret;
619}
620
621static void uart_flush_buffer(struct tty_struct *tty)
622{
623 struct uart_state *state = tty->driver_data;
624 struct uart_port *port;
625 unsigned long flags;
626
627 /*
628 * This means you called this function _after_ the port was
629 * closed. No cookie for you.
630 */
631 if (!state) {
632 WARN_ON(1);
633 return;
634 }
635
636 pr_debug("uart_flush_buffer(%d) called\n", tty->index);
637
638 port = uart_port_lock(state, flags);
639 if (!port)
640 return;
641 uart_circ_clear(&state->xmit);
642 if (port->ops->flush_buffer)
643 port->ops->flush_buffer(port);
644 uart_port_unlock(port, flags);
645 tty_port_tty_wakeup(&state->port);
646}
647
648/*
649 * This function is used to send a high-priority XON/XOFF character to
650 * the device
651 */
652static void uart_send_xchar(struct tty_struct *tty, char ch)
653{
654 struct uart_state *state = tty->driver_data;
655 struct uart_port *port;
656 unsigned long flags;
657
658 port = uart_port_ref(state);
659 if (!port)
660 return;
661
662 if (port->ops->send_xchar)
663 port->ops->send_xchar(port, ch);
664 else {
665 spin_lock_irqsave(&port->lock, flags);
666 port->x_char = ch;
667 if (ch)
668 port->ops->start_tx(port);
669 spin_unlock_irqrestore(&port->lock, flags);
670 }
671 uart_port_deref(port);
672}
673
674static void uart_throttle(struct tty_struct *tty)
675{
676 struct uart_state *state = tty->driver_data;
677 struct uart_port *port;
678 upstat_t mask = 0;
679
680 port = uart_port_ref(state);
681 if (!port)
682 return;
683
684 if (I_IXOFF(tty))
685 mask |= UPSTAT_AUTOXOFF;
686 if (C_CRTSCTS(tty))
687 mask |= UPSTAT_AUTORTS;
688
689 if (port->status & mask) {
690 port->ops->throttle(port);
691 mask &= ~port->status;
692 }
693
694 if (mask & UPSTAT_AUTORTS)
695 uart_clear_mctrl(port, TIOCM_RTS);
696
697 if (mask & UPSTAT_AUTOXOFF)
698 uart_send_xchar(tty, STOP_CHAR(tty));
699
700 uart_port_deref(port);
701}
702
703static void uart_unthrottle(struct tty_struct *tty)
704{
705 struct uart_state *state = tty->driver_data;
706 struct uart_port *port;
707 upstat_t mask = 0;
708
709 port = uart_port_ref(state);
710 if (!port)
711 return;
712
713 if (I_IXOFF(tty))
714 mask |= UPSTAT_AUTOXOFF;
715 if (C_CRTSCTS(tty))
716 mask |= UPSTAT_AUTORTS;
717
718 if (port->status & mask) {
719 port->ops->unthrottle(port);
720 mask &= ~port->status;
721 }
722
723 if (mask & UPSTAT_AUTORTS)
724 uart_set_mctrl(port, TIOCM_RTS);
725
726 if (mask & UPSTAT_AUTOXOFF)
727 uart_send_xchar(tty, START_CHAR(tty));
728
729 uart_port_deref(port);
730}
731
732static int uart_get_info(struct tty_port *port, struct serial_struct *retinfo)
733{
734 struct uart_state *state = container_of(port, struct uart_state, port);
735 struct uart_port *uport;
736 int ret = -ENODEV;
737
738 memset(retinfo, 0, sizeof(*retinfo));
739
740 /*
741 * Ensure the state we copy is consistent and no hardware changes
742 * occur as we go
743 */
744 mutex_lock(&port->mutex);
745 uport = uart_port_check(state);
746 if (!uport)
747 goto out;
748
749 retinfo->type = uport->type;
750 retinfo->line = uport->line;
751 retinfo->port = uport->iobase;
752 if (HIGH_BITS_OFFSET)
753 retinfo->port_high = (long) uport->iobase >> HIGH_BITS_OFFSET;
754 retinfo->irq = uport->irq;
755 retinfo->flags = (__force int)uport->flags;
756 retinfo->xmit_fifo_size = uport->fifosize;
757 retinfo->baud_base = uport->uartclk / 16;
758 retinfo->close_delay = jiffies_to_msecs(port->close_delay) / 10;
759 retinfo->closing_wait = port->closing_wait == ASYNC_CLOSING_WAIT_NONE ?
760 ASYNC_CLOSING_WAIT_NONE :
761 jiffies_to_msecs(port->closing_wait) / 10;
762 retinfo->custom_divisor = uport->custom_divisor;
763 retinfo->hub6 = uport->hub6;
764 retinfo->io_type = uport->iotype;
765 retinfo->iomem_reg_shift = uport->regshift;
766 retinfo->iomem_base = (void *)(unsigned long)uport->mapbase;
767
768 ret = 0;
769out:
770 mutex_unlock(&port->mutex);
771 return ret;
772}
773
774static int uart_get_info_user(struct tty_port *port,
775 struct serial_struct __user *retinfo)
776{
777 struct serial_struct tmp;
778
779 if (uart_get_info(port, &tmp) < 0)
780 return -EIO;
781
782 if (copy_to_user(retinfo, &tmp, sizeof(*retinfo)))
783 return -EFAULT;
784 return 0;
785}
786
787static int uart_set_info(struct tty_struct *tty, struct tty_port *port,
788 struct uart_state *state,
789 struct serial_struct *new_info)
790{
791 struct uart_port *uport = uart_port_check(state);
792 unsigned long new_port;
793 unsigned int change_irq, change_port, closing_wait;
794 unsigned int old_custom_divisor, close_delay;
795 upf_t old_flags, new_flags;
796 int retval = 0;
797
798 if (!uport)
799 return -EIO;
800
801 new_port = new_info->port;
802 if (HIGH_BITS_OFFSET)
803 new_port += (unsigned long) new_info->port_high << HIGH_BITS_OFFSET;
804
805 new_info->irq = irq_canonicalize(new_info->irq);
806 close_delay = msecs_to_jiffies(new_info->close_delay * 10);
807 closing_wait = new_info->closing_wait == ASYNC_CLOSING_WAIT_NONE ?
808 ASYNC_CLOSING_WAIT_NONE :
809 msecs_to_jiffies(new_info->closing_wait * 10);
810
811
812 change_irq = !(uport->flags & UPF_FIXED_PORT)
813 && new_info->irq != uport->irq;
814
815 /*
816 * Since changing the 'type' of the port changes its resource
817 * allocations, we should treat type changes the same as
818 * IO port changes.
819 */
820 change_port = !(uport->flags & UPF_FIXED_PORT)
821 && (new_port != uport->iobase ||
822 (unsigned long)new_info->iomem_base != uport->mapbase ||
823 new_info->hub6 != uport->hub6 ||
824 new_info->io_type != uport->iotype ||
825 new_info->iomem_reg_shift != uport->regshift ||
826 new_info->type != uport->type);
827
828 old_flags = uport->flags;
829 new_flags = (__force upf_t)new_info->flags;
830 old_custom_divisor = uport->custom_divisor;
831
832 if (!capable(CAP_SYS_ADMIN)) {
833 retval = -EPERM;
834 if (change_irq || change_port ||
835 (new_info->baud_base != uport->uartclk / 16) ||
836 (close_delay != port->close_delay) ||
837 (closing_wait != port->closing_wait) ||
838 (new_info->xmit_fifo_size &&
839 new_info->xmit_fifo_size != uport->fifosize) ||
840 (((new_flags ^ old_flags) & ~UPF_USR_MASK) != 0))
841 goto exit;
842 uport->flags = ((uport->flags & ~UPF_USR_MASK) |
843 (new_flags & UPF_USR_MASK));
844 uport->custom_divisor = new_info->custom_divisor;
845 goto check_and_exit;
846 }
847
848 /*
849 * Ask the low level driver to verify the settings.
850 */
851 if (uport->ops->verify_port)
852 retval = uport->ops->verify_port(uport, new_info);
853
854 if ((new_info->irq >= nr_irqs) || (new_info->irq < 0) ||
855 (new_info->baud_base < 9600))
856 retval = -EINVAL;
857
858 if (retval)
859 goto exit;
860
861 if (change_port || change_irq) {
862 retval = -EBUSY;
863
864 /*
865 * Make sure that we are the sole user of this port.
866 */
867 if (tty_port_users(port) > 1)
868 goto exit;
869
870 /*
871 * We need to shutdown the serial port at the old
872 * port/type/irq combination.
873 */
874 uart_shutdown(tty, state);
875 }
876
877 if (change_port) {
878 unsigned long old_iobase, old_mapbase;
879 unsigned int old_type, old_iotype, old_hub6, old_shift;
880
881 old_iobase = uport->iobase;
882 old_mapbase = uport->mapbase;
883 old_type = uport->type;
884 old_hub6 = uport->hub6;
885 old_iotype = uport->iotype;
886 old_shift = uport->regshift;
887
888 /*
889 * Free and release old regions
890 */
891 if (old_type != PORT_UNKNOWN && uport->ops->release_port)
892 uport->ops->release_port(uport);
893
894 uport->iobase = new_port;
895 uport->type = new_info->type;
896 uport->hub6 = new_info->hub6;
897 uport->iotype = new_info->io_type;
898 uport->regshift = new_info->iomem_reg_shift;
899 uport->mapbase = (unsigned long)new_info->iomem_base;
900
901 /*
902 * Claim and map the new regions
903 */
904 if (uport->type != PORT_UNKNOWN && uport->ops->request_port) {
905 retval = uport->ops->request_port(uport);
906 } else {
907 /* Always success - Jean II */
908 retval = 0;
909 }
910
911 /*
912 * If we fail to request resources for the
913 * new port, try to restore the old settings.
914 */
915 if (retval) {
916 uport->iobase = old_iobase;
917 uport->type = old_type;
918 uport->hub6 = old_hub6;
919 uport->iotype = old_iotype;
920 uport->regshift = old_shift;
921 uport->mapbase = old_mapbase;
922
923 if (old_type != PORT_UNKNOWN) {
924 retval = uport->ops->request_port(uport);
925 /*
926 * If we failed to restore the old settings,
927 * we fail like this.
928 */
929 if (retval)
930 uport->type = PORT_UNKNOWN;
931
932 /*
933 * We failed anyway.
934 */
935 retval = -EBUSY;
936 }
937
938 /* Added to return the correct error -Ram Gupta */
939 goto exit;
940 }
941 }
942
943 if (change_irq)
944 uport->irq = new_info->irq;
945 if (!(uport->flags & UPF_FIXED_PORT))
946 uport->uartclk = new_info->baud_base * 16;
947 uport->flags = (uport->flags & ~UPF_CHANGE_MASK) |
948 (new_flags & UPF_CHANGE_MASK);
949 uport->custom_divisor = new_info->custom_divisor;
950 port->close_delay = close_delay;
951 port->closing_wait = closing_wait;
952 if (new_info->xmit_fifo_size)
953 uport->fifosize = new_info->xmit_fifo_size;
954 port->low_latency = (uport->flags & UPF_LOW_LATENCY) ? 1 : 0;
955
956 check_and_exit:
957 retval = 0;
958 if (uport->type == PORT_UNKNOWN)
959 goto exit;
960 if (tty_port_initialized(port)) {
961 if (((old_flags ^ uport->flags) & UPF_SPD_MASK) ||
962 old_custom_divisor != uport->custom_divisor) {
963 /*
964 * If they're setting up a custom divisor or speed,
965 * instead of clearing it, then bitch about it.
966 */
967 if (uport->flags & UPF_SPD_MASK) {
968 dev_notice_ratelimited(uport->dev,
969 "%s sets custom speed on %s. This is deprecated.\n",
970 current->comm,
971 tty_name(port->tty));
972 }
973 uart_change_speed(tty, state, NULL);
974 }
975 } else {
976 retval = uart_startup(tty, state, 1);
977 if (retval == 0)
978 tty_port_set_initialized(port, true);
979 if (retval > 0)
980 retval = 0;
981 }
982 exit:
983 return retval;
984}
985
986static int uart_set_info_user(struct tty_struct *tty, struct uart_state *state,
987 struct serial_struct __user *newinfo)
988{
989 struct serial_struct new_serial;
990 struct tty_port *port = &state->port;
991 int retval;
992
993 if (copy_from_user(&new_serial, newinfo, sizeof(new_serial)))
994 return -EFAULT;
995
996 /*
997 * This semaphore protects port->count. It is also
998 * very useful to prevent opens. Also, take the
999 * port configuration semaphore to make sure that a
1000 * module insertion/removal doesn't change anything
1001 * under us.
1002 */
1003 mutex_lock(&port->mutex);
1004 retval = uart_set_info(tty, port, state, &new_serial);
1005 mutex_unlock(&port->mutex);
1006 return retval;
1007}
1008
1009/**
1010 * uart_get_lsr_info - get line status register info
1011 * @tty: tty associated with the UART
1012 * @state: UART being queried
1013 * @value: returned modem value
1014 */
1015static int uart_get_lsr_info(struct tty_struct *tty,
1016 struct uart_state *state, unsigned int __user *value)
1017{
1018 struct uart_port *uport = uart_port_check(state);
1019 unsigned int result;
1020
1021 result = uport->ops->tx_empty(uport);
1022
1023 /*
1024 * If we're about to load something into the transmit
1025 * register, we'll pretend the transmitter isn't empty to
1026 * avoid a race condition (depending on when the transmit
1027 * interrupt happens).
1028 */
1029 if (uport->x_char ||
1030 ((uart_circ_chars_pending(&state->xmit) > 0) &&
1031 !uart_tx_stopped(uport)))
1032 result &= ~TIOCSER_TEMT;
1033
1034 return put_user(result, value);
1035}
1036
1037static int uart_tiocmget(struct tty_struct *tty)
1038{
1039 struct uart_state *state = tty->driver_data;
1040 struct tty_port *port = &state->port;
1041 struct uart_port *uport;
1042 int result = -EIO;
1043
1044 mutex_lock(&port->mutex);
1045 uport = uart_port_check(state);
1046 if (!uport)
1047 goto out;
1048
1049 if (!tty_io_error(tty)) {
1050 result = uport->mctrl;
1051 spin_lock_irq(&uport->lock);
1052 result |= uport->ops->get_mctrl(uport);
1053 spin_unlock_irq(&uport->lock);
1054 }
1055out:
1056 mutex_unlock(&port->mutex);
1057 return result;
1058}
1059
1060static int
1061uart_tiocmset(struct tty_struct *tty, unsigned int set, unsigned int clear)
1062{
1063 struct uart_state *state = tty->driver_data;
1064 struct tty_port *port = &state->port;
1065 struct uart_port *uport;
1066 int ret = -EIO;
1067
1068 mutex_lock(&port->mutex);
1069 uport = uart_port_check(state);
1070 if (!uport)
1071 goto out;
1072
1073 if (!tty_io_error(tty)) {
1074 uart_update_mctrl(uport, set, clear);
1075 ret = 0;
1076 }
1077out:
1078 mutex_unlock(&port->mutex);
1079 return ret;
1080}
1081
1082static int uart_break_ctl(struct tty_struct *tty, int break_state)
1083{
1084 struct uart_state *state = tty->driver_data;
1085 struct tty_port *port = &state->port;
1086 struct uart_port *uport;
1087 int ret = -EIO;
1088
1089 mutex_lock(&port->mutex);
1090 uport = uart_port_check(state);
1091 if (!uport)
1092 goto out;
1093
1094 if (uport->type != PORT_UNKNOWN)
1095 uport->ops->break_ctl(uport, break_state);
1096 ret = 0;
1097out:
1098 mutex_unlock(&port->mutex);
1099 return ret;
1100}
1101
1102static int uart_do_autoconfig(struct tty_struct *tty,struct uart_state *state)
1103{
1104 struct tty_port *port = &state->port;
1105 struct uart_port *uport;
1106 int flags, ret;
1107
1108 if (!capable(CAP_SYS_ADMIN))
1109 return -EPERM;
1110
1111 /*
1112 * Take the per-port semaphore. This prevents count from
1113 * changing, and hence any extra opens of the port while
1114 * we're auto-configuring.
1115 */
1116 if (mutex_lock_interruptible(&port->mutex))
1117 return -ERESTARTSYS;
1118
1119 uport = uart_port_check(state);
1120 if (!uport) {
1121 ret = -EIO;
1122 goto out;
1123 }
1124
1125 ret = -EBUSY;
1126 if (tty_port_users(port) == 1) {
1127 uart_shutdown(tty, state);
1128
1129 /*
1130 * If we already have a port type configured,
1131 * we must release its resources.
1132 */
1133 if (uport->type != PORT_UNKNOWN && uport->ops->release_port)
1134 uport->ops->release_port(uport);
1135
1136 flags = UART_CONFIG_TYPE;
1137 if (uport->flags & UPF_AUTO_IRQ)
1138 flags |= UART_CONFIG_IRQ;
1139
1140 /*
1141 * This will claim the ports resources if
1142 * a port is found.
1143 */
1144 uport->ops->config_port(uport, flags);
1145
1146 ret = uart_startup(tty, state, 1);
1147 if (ret == 0)
1148 tty_port_set_initialized(port, true);
1149 if (ret > 0)
1150 ret = 0;
1151 }
1152out:
1153 mutex_unlock(&port->mutex);
1154 return ret;
1155}
1156
1157static void uart_enable_ms(struct uart_port *uport)
1158{
1159 /*
1160 * Force modem status interrupts on
1161 */
1162 if (uport->ops->enable_ms)
1163 uport->ops->enable_ms(uport);
1164}
1165
1166/*
1167 * Wait for any of the 4 modem inputs (DCD,RI,DSR,CTS) to change
1168 * - mask passed in arg for lines of interest
1169 * (use |'ed TIOCM_RNG/DSR/CD/CTS for masking)
1170 * Caller should use TIOCGICOUNT to see which one it was
1171 *
1172 * FIXME: This wants extracting into a common all driver implementation
1173 * of TIOCMWAIT using tty_port.
1174 */
1175static int uart_wait_modem_status(struct uart_state *state, unsigned long arg)
1176{
1177 struct uart_port *uport;
1178 struct tty_port *port = &state->port;
1179 DECLARE_WAITQUEUE(wait, current);
1180 struct uart_icount cprev, cnow;
1181 int ret;
1182
1183 /*
1184 * note the counters on entry
1185 */
1186 uport = uart_port_ref(state);
1187 if (!uport)
1188 return -EIO;
1189 spin_lock_irq(&uport->lock);
1190 memcpy(&cprev, &uport->icount, sizeof(struct uart_icount));
1191 uart_enable_ms(uport);
1192 spin_unlock_irq(&uport->lock);
1193
1194 add_wait_queue(&port->delta_msr_wait, &wait);
1195 for (;;) {
1196 spin_lock_irq(&uport->lock);
1197 memcpy(&cnow, &uport->icount, sizeof(struct uart_icount));
1198 spin_unlock_irq(&uport->lock);
1199
1200 set_current_state(TASK_INTERRUPTIBLE);
1201
1202 if (((arg & TIOCM_RNG) && (cnow.rng != cprev.rng)) ||
1203 ((arg & TIOCM_DSR) && (cnow.dsr != cprev.dsr)) ||
1204 ((arg & TIOCM_CD) && (cnow.dcd != cprev.dcd)) ||
1205 ((arg & TIOCM_CTS) && (cnow.cts != cprev.cts))) {
1206 ret = 0;
1207 break;
1208 }
1209
1210 schedule();
1211
1212 /* see if a signal did it */
1213 if (signal_pending(current)) {
1214 ret = -ERESTARTSYS;
1215 break;
1216 }
1217
1218 cprev = cnow;
1219 }
1220 __set_current_state(TASK_RUNNING);
1221 remove_wait_queue(&port->delta_msr_wait, &wait);
1222 uart_port_deref(uport);
1223
1224 return ret;
1225}
1226
1227/*
1228 * Get counter of input serial line interrupts (DCD,RI,DSR,CTS)
1229 * Return: write counters to the user passed counter struct
1230 * NB: both 1->0 and 0->1 transitions are counted except for
1231 * RI where only 0->1 is counted.
1232 */
1233static int uart_get_icount(struct tty_struct *tty,
1234 struct serial_icounter_struct *icount)
1235{
1236 struct uart_state *state = tty->driver_data;
1237 struct uart_icount cnow;
1238 struct uart_port *uport;
1239
1240 uport = uart_port_ref(state);
1241 if (!uport)
1242 return -EIO;
1243 spin_lock_irq(&uport->lock);
1244 memcpy(&cnow, &uport->icount, sizeof(struct uart_icount));
1245 spin_unlock_irq(&uport->lock);
1246 uart_port_deref(uport);
1247
1248 icount->cts = cnow.cts;
1249 icount->dsr = cnow.dsr;
1250 icount->rng = cnow.rng;
1251 icount->dcd = cnow.dcd;
1252 icount->rx = cnow.rx;
1253 icount->tx = cnow.tx;
1254 icount->frame = cnow.frame;
1255 icount->overrun = cnow.overrun;
1256 icount->parity = cnow.parity;
1257 icount->brk = cnow.brk;
1258 icount->buf_overrun = cnow.buf_overrun;
1259
1260 return 0;
1261}
1262
1263static int uart_get_rs485_config(struct uart_port *port,
1264 struct serial_rs485 __user *rs485)
1265{
1266 unsigned long flags;
1267 struct serial_rs485 aux;
1268
1269 spin_lock_irqsave(&port->lock, flags);
1270 aux = port->rs485;
1271 spin_unlock_irqrestore(&port->lock, flags);
1272
1273 if (copy_to_user(rs485, &aux, sizeof(aux)))
1274 return -EFAULT;
1275
1276 return 0;
1277}
1278
1279static int uart_set_rs485_config(struct uart_port *port,
1280 struct serial_rs485 __user *rs485_user)
1281{
1282 struct serial_rs485 rs485;
1283 int ret;
1284 unsigned long flags;
1285
1286 if (!port->rs485_config)
1287 return -ENOIOCTLCMD;
1288
1289 if (copy_from_user(&rs485, rs485_user, sizeof(*rs485_user)))
1290 return -EFAULT;
1291
1292 spin_lock_irqsave(&port->lock, flags);
1293 ret = port->rs485_config(port, &rs485);
1294 spin_unlock_irqrestore(&port->lock, flags);
1295 if (ret)
1296 return ret;
1297
1298 if (copy_to_user(rs485_user, &port->rs485, sizeof(port->rs485)))
1299 return -EFAULT;
1300
1301 return 0;
1302}
1303
1304/*
1305 * Called via sys_ioctl. We can use spin_lock_irq() here.
1306 */
1307static int
1308uart_ioctl(struct tty_struct *tty, unsigned int cmd, unsigned long arg)
1309{
1310 struct uart_state *state = tty->driver_data;
1311 struct tty_port *port = &state->port;
1312 struct uart_port *uport;
1313 void __user *uarg = (void __user *)arg;
1314 int ret = -ENOIOCTLCMD;
1315
1316
1317 /*
1318 * These ioctls don't rely on the hardware to be present.
1319 */
1320 switch (cmd) {
1321 case TIOCGSERIAL:
1322 ret = uart_get_info_user(port, uarg);
1323 break;
1324
1325 case TIOCSSERIAL:
1326 down_write(&tty->termios_rwsem);
1327 ret = uart_set_info_user(tty, state, uarg);
1328 up_write(&tty->termios_rwsem);
1329 break;
1330
1331 case TIOCSERCONFIG:
1332 down_write(&tty->termios_rwsem);
1333 ret = uart_do_autoconfig(tty, state);
1334 up_write(&tty->termios_rwsem);
1335 break;
1336
1337 case TIOCSERGWILD: /* obsolete */
1338 case TIOCSERSWILD: /* obsolete */
1339 ret = 0;
1340 break;
1341 }
1342
1343 if (ret != -ENOIOCTLCMD)
1344 goto out;
1345
1346 if (tty_io_error(tty)) {
1347 ret = -EIO;
1348 goto out;
1349 }
1350
1351 /*
1352 * The following should only be used when hardware is present.
1353 */
1354 switch (cmd) {
1355 case TIOCMIWAIT:
1356 ret = uart_wait_modem_status(state, arg);
1357 break;
1358 }
1359
1360 if (ret != -ENOIOCTLCMD)
1361 goto out;
1362
1363 mutex_lock(&port->mutex);
1364 uport = uart_port_check(state);
1365
1366 if (!uport || tty_io_error(tty)) {
1367 ret = -EIO;
1368 goto out_up;
1369 }
1370
1371 /*
1372 * All these rely on hardware being present and need to be
1373 * protected against the tty being hung up.
1374 */
1375
1376 switch (cmd) {
1377 case TIOCSERGETLSR: /* Get line status register */
1378 ret = uart_get_lsr_info(tty, state, uarg);
1379 break;
1380
1381 case TIOCGRS485:
1382 ret = uart_get_rs485_config(uport, uarg);
1383 break;
1384
1385 case TIOCSRS485:
1386 ret = uart_set_rs485_config(uport, uarg);
1387 break;
1388 default:
1389 if (uport->ops->ioctl)
1390 ret = uport->ops->ioctl(uport, cmd, arg);
1391 break;
1392 }
1393out_up:
1394 mutex_unlock(&port->mutex);
1395out:
1396 return ret;
1397}
1398
1399static void uart_set_ldisc(struct tty_struct *tty)
1400{
1401 struct uart_state *state = tty->driver_data;
1402 struct uart_port *uport;
1403
1404 mutex_lock(&state->port.mutex);
1405 uport = uart_port_check(state);
1406 if (uport && uport->ops->set_ldisc)
1407 uport->ops->set_ldisc(uport, &tty->termios);
1408 mutex_unlock(&state->port.mutex);
1409}
1410
1411static void uart_set_termios(struct tty_struct *tty,
1412 struct ktermios *old_termios)
1413{
1414 struct uart_state *state = tty->driver_data;
1415 struct uart_port *uport;
1416 unsigned int cflag = tty->termios.c_cflag;
1417 unsigned int iflag_mask = IGNBRK|BRKINT|IGNPAR|PARMRK|INPCK;
1418 bool sw_changed = false;
1419
1420 mutex_lock(&state->port.mutex);
1421 uport = uart_port_check(state);
1422 if (!uport)
1423 goto out;
1424
1425 /*
1426 * Drivers doing software flow control also need to know
1427 * about changes to these input settings.
1428 */
1429 if (uport->flags & UPF_SOFT_FLOW) {
1430 iflag_mask |= IXANY|IXON|IXOFF;
1431 sw_changed =
1432 tty->termios.c_cc[VSTART] != old_termios->c_cc[VSTART] ||
1433 tty->termios.c_cc[VSTOP] != old_termios->c_cc[VSTOP];
1434 }
1435
1436 /*
1437 * These are the bits that are used to setup various
1438 * flags in the low level driver. We can ignore the Bfoo
1439 * bits in c_cflag; c_[io]speed will always be set
1440 * appropriately by set_termios() in tty_ioctl.c
1441 */
1442 if ((cflag ^ old_termios->c_cflag) == 0 &&
1443 tty->termios.c_ospeed == old_termios->c_ospeed &&
1444 tty->termios.c_ispeed == old_termios->c_ispeed &&
1445 ((tty->termios.c_iflag ^ old_termios->c_iflag) & iflag_mask) == 0 &&
1446 !sw_changed) {
1447 goto out;
1448 }
1449
1450 uart_change_speed(tty, state, old_termios);
1451 /* reload cflag from termios; port driver may have overriden flags */
1452 cflag = tty->termios.c_cflag;
1453
1454 /* Handle transition to B0 status */
1455 if ((old_termios->c_cflag & CBAUD) && !(cflag & CBAUD))
1456 uart_clear_mctrl(uport, TIOCM_RTS | TIOCM_DTR);
1457 /* Handle transition away from B0 status */
1458 else if (!(old_termios->c_cflag & CBAUD) && (cflag & CBAUD)) {
1459 unsigned int mask = TIOCM_DTR;
1460 if (!(cflag & CRTSCTS) || !tty_throttled(tty))
1461 mask |= TIOCM_RTS;
1462 uart_set_mctrl(uport, mask);
1463 }
1464out:
1465 mutex_unlock(&state->port.mutex);
1466}
1467
1468/*
1469 * Calls to uart_close() are serialised via the tty_lock in
1470 * drivers/tty/tty_io.c:tty_release()
1471 * drivers/tty/tty_io.c:do_tty_hangup()
1472 */
1473static void uart_close(struct tty_struct *tty, struct file *filp)
1474{
1475 struct uart_state *state = tty->driver_data;
1476
1477 if (!state) {
1478 struct uart_driver *drv = tty->driver->driver_state;
1479 struct tty_port *port;
1480
1481 state = drv->state + tty->index;
1482 port = &state->port;
1483 spin_lock_irq(&port->lock);
1484 --port->count;
1485 spin_unlock_irq(&port->lock);
1486 return;
1487 }
1488
1489 pr_debug("uart_close(%d) called\n", tty->index);
1490
1491 tty_port_close(tty->port, tty, filp);
1492}
1493
1494static void uart_tty_port_shutdown(struct tty_port *port)
1495{
1496 struct uart_state *state = container_of(port, struct uart_state, port);
1497 struct uart_port *uport = uart_port_check(state);
1498
1499 /*
1500 * At this point, we stop accepting input. To do this, we
1501 * disable the receive line status interrupts.
1502 */
1503 if (WARN(!uport, "detached port still initialized!\n"))
1504 return;
1505
1506 spin_lock_irq(&uport->lock);
1507 uport->ops->stop_rx(uport);
1508 spin_unlock_irq(&uport->lock);
1509
1510 uart_port_shutdown(port);
1511
1512 /*
1513 * It's possible for shutdown to be called after suspend if we get
1514 * a DCD drop (hangup) at just the right time. Clear suspended bit so
1515 * we don't try to resume a port that has been shutdown.
1516 */
1517 tty_port_set_suspended(port, 0);
1518
1519 uart_change_pm(state, UART_PM_STATE_OFF);
1520
1521}
1522
1523static void uart_wait_until_sent(struct tty_struct *tty, int timeout)
1524{
1525 struct uart_state *state = tty->driver_data;
1526 struct uart_port *port;
1527 unsigned long char_time, expire;
1528
1529 port = uart_port_ref(state);
1530 if (!port)
1531 return;
1532
1533 if (port->type == PORT_UNKNOWN || port->fifosize == 0) {
1534 uart_port_deref(port);
1535 return;
1536 }
1537
1538 /*
1539 * Set the check interval to be 1/5 of the estimated time to
1540 * send a single character, and make it at least 1. The check
1541 * interval should also be less than the timeout.
1542 *
1543 * Note: we have to use pretty tight timings here to satisfy
1544 * the NIST-PCTS.
1545 */
1546 char_time = (port->timeout - HZ/50) / port->fifosize;
1547 char_time = char_time / 5;
1548 if (char_time == 0)
1549 char_time = 1;
1550 if (timeout && timeout < char_time)
1551 char_time = timeout;
1552
1553 /*
1554 * If the transmitter hasn't cleared in twice the approximate
1555 * amount of time to send the entire FIFO, it probably won't
1556 * ever clear. This assumes the UART isn't doing flow
1557 * control, which is currently the case. Hence, if it ever
1558 * takes longer than port->timeout, this is probably due to a
1559 * UART bug of some kind. So, we clamp the timeout parameter at
1560 * 2*port->timeout.
1561 */
1562 if (timeout == 0 || timeout > 2 * port->timeout)
1563 timeout = 2 * port->timeout;
1564
1565 expire = jiffies + timeout;
1566
1567 pr_debug("uart_wait_until_sent(%d), jiffies=%lu, expire=%lu...\n",
1568 port->line, jiffies, expire);
1569
1570 /*
1571 * Check whether the transmitter is empty every 'char_time'.
1572 * 'timeout' / 'expire' give us the maximum amount of time
1573 * we wait.
1574 */
1575 while (!port->ops->tx_empty(port)) {
1576 msleep_interruptible(jiffies_to_msecs(char_time));
1577 if (signal_pending(current))
1578 break;
1579 if (time_after(jiffies, expire))
1580 break;
1581 }
1582 uart_port_deref(port);
1583}
1584
1585/*
1586 * Calls to uart_hangup() are serialised by the tty_lock in
1587 * drivers/tty/tty_io.c:do_tty_hangup()
1588 * This runs from a workqueue and can sleep for a _short_ time only.
1589 */
1590static void uart_hangup(struct tty_struct *tty)
1591{
1592 struct uart_state *state = tty->driver_data;
1593 struct tty_port *port = &state->port;
1594 struct uart_port *uport;
1595 unsigned long flags;
1596
1597 pr_debug("uart_hangup(%d)\n", tty->index);
1598
1599 mutex_lock(&port->mutex);
1600 uport = uart_port_check(state);
1601 WARN(!uport, "hangup of detached port!\n");
1602
1603 if (tty_port_active(port)) {
1604 uart_flush_buffer(tty);
1605 uart_shutdown(tty, state);
1606 spin_lock_irqsave(&port->lock, flags);
1607 port->count = 0;
1608 spin_unlock_irqrestore(&port->lock, flags);
1609 tty_port_set_active(port, 0);
1610 tty_port_tty_set(port, NULL);
1611 if (uport && !uart_console(uport))
1612 uart_change_pm(state, UART_PM_STATE_OFF);
1613 wake_up_interruptible(&port->open_wait);
1614 wake_up_interruptible(&port->delta_msr_wait);
1615 }
1616 mutex_unlock(&port->mutex);
1617}
1618
1619/* uport == NULL if uart_port has already been removed */
1620static void uart_port_shutdown(struct tty_port *port)
1621{
1622 struct uart_state *state = container_of(port, struct uart_state, port);
1623 struct uart_port *uport = uart_port_check(state);
1624
1625 /*
1626 * clear delta_msr_wait queue to avoid mem leaks: we may free
1627 * the irq here so the queue might never be woken up. Note
1628 * that we won't end up waiting on delta_msr_wait again since
1629 * any outstanding file descriptors should be pointing at
1630 * hung_up_tty_fops now.
1631 */
1632 wake_up_interruptible(&port->delta_msr_wait);
1633
1634 /*
1635 * Free the IRQ and disable the port.
1636 */
1637 if (uport)
1638 uport->ops->shutdown(uport);
1639
1640 /*
1641 * Ensure that the IRQ handler isn't running on another CPU.
1642 */
1643 if (uport)
1644 synchronize_irq(uport->irq);
1645}
1646
1647static int uart_carrier_raised(struct tty_port *port)
1648{
1649 struct uart_state *state = container_of(port, struct uart_state, port);
1650 struct uart_port *uport;
1651 int mctrl;
1652
1653 uport = uart_port_ref(state);
1654 /*
1655 * Should never observe uport == NULL since checks for hangup should
1656 * abort the tty_port_block_til_ready() loop before checking for carrier
1657 * raised -- but report carrier raised if it does anyway so open will
1658 * continue and not sleep
1659 */
1660 if (WARN_ON(!uport))
1661 return 1;
1662 spin_lock_irq(&uport->lock);
1663 uart_enable_ms(uport);
1664 mctrl = uport->ops->get_mctrl(uport);
1665 spin_unlock_irq(&uport->lock);
1666 uart_port_deref(uport);
1667 if (mctrl & TIOCM_CAR)
1668 return 1;
1669 return 0;
1670}
1671
1672static void uart_dtr_rts(struct tty_port *port, int raise)
1673{
1674 struct uart_state *state = container_of(port, struct uart_state, port);
1675 struct uart_port *uport;
1676
1677 uport = uart_port_ref(state);
1678 if (!uport)
1679 return;
1680 uart_port_dtr_rts(uport, raise);
1681 uart_port_deref(uport);
1682}
1683
1684/*
1685 * Calls to uart_open are serialised by the tty_lock in
1686 * drivers/tty/tty_io.c:tty_open()
1687 * Note that if this fails, then uart_close() _will_ be called.
1688 *
1689 * In time, we want to scrap the "opening nonpresent ports"
1690 * behaviour and implement an alternative way for setserial
1691 * to set base addresses/ports/types. This will allow us to
1692 * get rid of a certain amount of extra tests.
1693 */
1694static int uart_open(struct tty_struct *tty, struct file *filp)
1695{
1696 struct uart_driver *drv = tty->driver->driver_state;
1697 int retval, line = tty->index;
1698 struct uart_state *state = drv->state + line;
1699
1700 tty->driver_data = state;
1701
1702 retval = tty_port_open(&state->port, tty, filp);
1703 if (retval > 0)
1704 retval = 0;
1705
1706 return retval;
1707}
1708
1709static int uart_port_activate(struct tty_port *port, struct tty_struct *tty)
1710{
1711 struct uart_state *state = container_of(port, struct uart_state, port);
1712 struct uart_port *uport;
1713
1714 uport = uart_port_check(state);
1715 if (!uport || uport->flags & UPF_DEAD)
1716 return -ENXIO;
1717
1718 port->low_latency = (uport->flags & UPF_LOW_LATENCY) ? 1 : 0;
1719
1720 /*
1721 * Start up the serial port.
1722 */
1723 return uart_startup(tty, state, 0);
1724}
1725
1726static const char *uart_type(struct uart_port *port)
1727{
1728 const char *str = NULL;
1729
1730 if (port->ops->type)
1731 str = port->ops->type(port);
1732
1733 if (!str)
1734 str = "unknown";
1735
1736 return str;
1737}
1738
1739#ifdef CONFIG_PROC_FS
1740
1741static void uart_line_info(struct seq_file *m, struct uart_driver *drv, int i)
1742{
1743 struct uart_state *state = drv->state + i;
1744 struct tty_port *port = &state->port;
1745 enum uart_pm_state pm_state;
1746 struct uart_port *uport;
1747 char stat_buf[32];
1748 unsigned int status;
1749 int mmio;
1750
1751 mutex_lock(&port->mutex);
1752 uport = uart_port_check(state);
1753 if (!uport)
1754 goto out;
1755
1756 mmio = uport->iotype >= UPIO_MEM;
1757 seq_printf(m, "%d: uart:%s %s%08llX irq:%d",
1758 uport->line, uart_type(uport),
1759 mmio ? "mmio:0x" : "port:",
1760 mmio ? (unsigned long long)uport->mapbase
1761 : (unsigned long long)uport->iobase,
1762 uport->irq);
1763
1764 if (uport->type == PORT_UNKNOWN) {
1765 seq_putc(m, '\n');
1766 goto out;
1767 }
1768
1769 if (capable(CAP_SYS_ADMIN)) {
1770 pm_state = state->pm_state;
1771 if (pm_state != UART_PM_STATE_ON)
1772 uart_change_pm(state, UART_PM_STATE_ON);
1773 spin_lock_irq(&uport->lock);
1774 status = uport->ops->get_mctrl(uport);
1775 spin_unlock_irq(&uport->lock);
1776 if (pm_state != UART_PM_STATE_ON)
1777 uart_change_pm(state, pm_state);
1778
1779 seq_printf(m, " tx:%d rx:%d",
1780 uport->icount.tx, uport->icount.rx);
1781 if (uport->icount.frame)
1782 seq_printf(m, " fe:%d", uport->icount.frame);
1783 if (uport->icount.parity)
1784 seq_printf(m, " pe:%d", uport->icount.parity);
1785 if (uport->icount.brk)
1786 seq_printf(m, " brk:%d", uport->icount.brk);
1787 if (uport->icount.overrun)
1788 seq_printf(m, " oe:%d", uport->icount.overrun);
1789 if (uport->icount.buf_overrun)
1790 seq_printf(m, " bo:%d", uport->icount.buf_overrun);
1791
1792#define INFOBIT(bit, str) \
1793 if (uport->mctrl & (bit)) \
1794 strncat(stat_buf, (str), sizeof(stat_buf) - \
1795 strlen(stat_buf) - 2)
1796#define STATBIT(bit, str) \
1797 if (status & (bit)) \
1798 strncat(stat_buf, (str), sizeof(stat_buf) - \
1799 strlen(stat_buf) - 2)
1800
1801 stat_buf[0] = '\0';
1802 stat_buf[1] = '\0';
1803 INFOBIT(TIOCM_RTS, "|RTS");
1804 STATBIT(TIOCM_CTS, "|CTS");
1805 INFOBIT(TIOCM_DTR, "|DTR");
1806 STATBIT(TIOCM_DSR, "|DSR");
1807 STATBIT(TIOCM_CAR, "|CD");
1808 STATBIT(TIOCM_RNG, "|RI");
1809 if (stat_buf[0])
1810 stat_buf[0] = ' ';
1811
1812 seq_puts(m, stat_buf);
1813 }
1814 seq_putc(m, '\n');
1815#undef STATBIT
1816#undef INFOBIT
1817out:
1818 mutex_unlock(&port->mutex);
1819}
1820
1821static int uart_proc_show(struct seq_file *m, void *v)
1822{
1823 struct tty_driver *ttydrv = m->private;
1824 struct uart_driver *drv = ttydrv->driver_state;
1825 int i;
1826
1827 seq_printf(m, "serinfo:1.0 driver%s%s revision:%s\n", "", "", "");
1828 for (i = 0; i < drv->nr; i++)
1829 uart_line_info(m, drv, i);
1830 return 0;
1831}
1832
1833static int uart_proc_open(struct inode *inode, struct file *file)
1834{
1835 return single_open(file, uart_proc_show, PDE_DATA(inode));
1836}
1837
1838static const struct file_operations uart_proc_fops = {
1839 .owner = THIS_MODULE,
1840 .open = uart_proc_open,
1841 .read = seq_read,
1842 .llseek = seq_lseek,
1843 .release = single_release,
1844};
1845#endif
1846
1847#if defined(CONFIG_SERIAL_CORE_CONSOLE) || defined(CONFIG_CONSOLE_POLL)
1848/**
1849 * uart_console_write - write a console message to a serial port
1850 * @port: the port to write the message
1851 * @s: array of characters
1852 * @count: number of characters in string to write
1853 * @putchar: function to write character to port
1854 */
1855void uart_console_write(struct uart_port *port, const char *s,
1856 unsigned int count,
1857 void (*putchar)(struct uart_port *, int))
1858{
1859 unsigned int i;
1860
1861 for (i = 0; i < count; i++, s++) {
1862 if (*s == '\n')
1863 putchar(port, '\r');
1864 putchar(port, *s);
1865 }
1866}
1867EXPORT_SYMBOL_GPL(uart_console_write);
1868
1869/*
1870 * Check whether an invalid uart number has been specified, and
1871 * if so, search for the first available port that does have
1872 * console support.
1873 */
1874struct uart_port * __init
1875uart_get_console(struct uart_port *ports, int nr, struct console *co)
1876{
1877 int idx = co->index;
1878
1879 if (idx < 0 || idx >= nr || (ports[idx].iobase == 0 &&
1880 ports[idx].membase == NULL))
1881 for (idx = 0; idx < nr; idx++)
1882 if (ports[idx].iobase != 0 ||
1883 ports[idx].membase != NULL)
1884 break;
1885
1886 co->index = idx;
1887
1888 return ports + idx;
1889}
1890
1891/**
1892 * uart_parse_earlycon - Parse earlycon options
1893 * @p: ptr to 2nd field (ie., just beyond '<name>,')
1894 * @iotype: ptr for decoded iotype (out)
1895 * @addr: ptr for decoded mapbase/iobase (out)
1896 * @options: ptr for <options> field; NULL if not present (out)
1897 *
1898 * Decodes earlycon kernel command line parameters of the form
1899 * earlycon=<name>,io|mmio|mmio16|mmio32|mmio32be|mmio32native,<addr>,<options>
1900 * console=<name>,io|mmio|mmio16|mmio32|mmio32be|mmio32native,<addr>,<options>
1901 *
1902 * The optional form
1903 * earlycon=<name>,0x<addr>,<options>
1904 * console=<name>,0x<addr>,<options>
1905 * is also accepted; the returned @iotype will be UPIO_MEM.
1906 *
1907 * Returns 0 on success or -EINVAL on failure
1908 */
1909int uart_parse_earlycon(char *p, unsigned char *iotype, resource_size_t *addr,
1910 char **options)
1911{
1912 if (strncmp(p, "mmio,", 5) == 0) {
1913 *iotype = UPIO_MEM;
1914 p += 5;
1915 } else if (strncmp(p, "mmio16,", 7) == 0) {
1916 *iotype = UPIO_MEM16;
1917 p += 7;
1918 } else if (strncmp(p, "mmio32,", 7) == 0) {
1919 *iotype = UPIO_MEM32;
1920 p += 7;
1921 } else if (strncmp(p, "mmio32be,", 9) == 0) {
1922 *iotype = UPIO_MEM32BE;
1923 p += 9;
1924 } else if (strncmp(p, "mmio32native,", 13) == 0) {
1925 *iotype = IS_ENABLED(CONFIG_CPU_BIG_ENDIAN) ?
1926 UPIO_MEM32BE : UPIO_MEM32;
1927 p += 13;
1928 } else if (strncmp(p, "io,", 3) == 0) {
1929 *iotype = UPIO_PORT;
1930 p += 3;
1931 } else if (strncmp(p, "0x", 2) == 0) {
1932 *iotype = UPIO_MEM;
1933 } else {
1934 return -EINVAL;
1935 }
1936
1937 /*
1938 * Before you replace it with kstrtoull(), think about options separator
1939 * (',') it will not tolerate
1940 */
1941 *addr = simple_strtoull(p, NULL, 0);
1942 p = strchr(p, ',');
1943 if (p)
1944 p++;
1945
1946 *options = p;
1947 return 0;
1948}
1949EXPORT_SYMBOL_GPL(uart_parse_earlycon);
1950
1951/**
1952 * uart_parse_options - Parse serial port baud/parity/bits/flow control.
1953 * @options: pointer to option string
1954 * @baud: pointer to an 'int' variable for the baud rate.
1955 * @parity: pointer to an 'int' variable for the parity.
1956 * @bits: pointer to an 'int' variable for the number of data bits.
1957 * @flow: pointer to an 'int' variable for the flow control character.
1958 *
1959 * uart_parse_options decodes a string containing the serial console
1960 * options. The format of the string is <baud><parity><bits><flow>,
1961 * eg: 115200n8r
1962 */
1963void
1964uart_parse_options(const char *options, int *baud, int *parity,
1965 int *bits, int *flow)
1966{
1967 const char *s = options;
1968
1969 *baud = simple_strtoul(s, NULL, 10);
1970 while (*s >= '0' && *s <= '9')
1971 s++;
1972 if (*s)
1973 *parity = *s++;
1974 if (*s)
1975 *bits = *s++ - '0';
1976 if (*s)
1977 *flow = *s;
1978}
1979EXPORT_SYMBOL_GPL(uart_parse_options);
1980
1981/**
1982 * uart_set_options - setup the serial console parameters
1983 * @port: pointer to the serial ports uart_port structure
1984 * @co: console pointer
1985 * @baud: baud rate
1986 * @parity: parity character - 'n' (none), 'o' (odd), 'e' (even)
1987 * @bits: number of data bits
1988 * @flow: flow control character - 'r' (rts)
1989 */
1990int
1991uart_set_options(struct uart_port *port, struct console *co,
1992 int baud, int parity, int bits, int flow)
1993{
1994 struct ktermios termios;
1995 static struct ktermios dummy;
1996
1997 /*
1998 * Ensure that the serial console lock is initialised
1999 * early.
2000 * If this port is a console, then the spinlock is already
2001 * initialised.
2002 */
2003 if (!(uart_console(port) && (port->cons->flags & CON_ENABLED))) {
2004 spin_lock_init(&port->lock);
2005 lockdep_set_class(&port->lock, &port_lock_key);
2006 }
2007
2008 memset(&termios, 0, sizeof(struct ktermios));
2009
2010 termios.c_cflag |= CREAD | HUPCL | CLOCAL;
2011 tty_termios_encode_baud_rate(&termios, baud, baud);
2012
2013 if (bits == 7)
2014 termios.c_cflag |= CS7;
2015 else
2016 termios.c_cflag |= CS8;
2017
2018 switch (parity) {
2019 case 'o': case 'O':
2020 termios.c_cflag |= PARODD;
2021 /*fall through*/
2022 case 'e': case 'E':
2023 termios.c_cflag |= PARENB;
2024 break;
2025 }
2026
2027 if (flow == 'r')
2028 termios.c_cflag |= CRTSCTS;
2029
2030 /*
2031 * some uarts on other side don't support no flow control.
2032 * So we set * DTR in host uart to make them happy
2033 */
2034 port->mctrl |= TIOCM_DTR;
2035
2036 port->ops->set_termios(port, &termios, &dummy);
2037 /*
2038 * Allow the setting of the UART parameters with a NULL console
2039 * too:
2040 */
2041 if (co)
2042 co->cflag = termios.c_cflag;
2043
2044 return 0;
2045}
2046EXPORT_SYMBOL_GPL(uart_set_options);
2047#endif /* CONFIG_SERIAL_CORE_CONSOLE */
2048
2049/**
2050 * uart_change_pm - set power state of the port
2051 *
2052 * @state: port descriptor
2053 * @pm_state: new state
2054 *
2055 * Locking: port->mutex has to be held
2056 */
2057static void uart_change_pm(struct uart_state *state,
2058 enum uart_pm_state pm_state)
2059{
2060 struct uart_port *port = uart_port_check(state);
2061
2062 if (state->pm_state != pm_state) {
2063 if (port && port->ops->pm)
2064 port->ops->pm(port, pm_state, state->pm_state);
2065 state->pm_state = pm_state;
2066 }
2067}
2068
2069struct uart_match {
2070 struct uart_port *port;
2071 struct uart_driver *driver;
2072};
2073
2074static int serial_match_port(struct device *dev, void *data)
2075{
2076 struct uart_match *match = data;
2077 struct tty_driver *tty_drv = match->driver->tty_driver;
2078 dev_t devt = MKDEV(tty_drv->major, tty_drv->minor_start) +
2079 match->port->line;
2080
2081 return dev->devt == devt; /* Actually, only one tty per port */
2082}
2083
2084int uart_suspend_port(struct uart_driver *drv, struct uart_port *uport)
2085{
2086 struct uart_state *state = drv->state + uport->line;
2087 struct tty_port *port = &state->port;
2088 struct device *tty_dev;
2089 struct uart_match match = {uport, drv};
2090
2091 mutex_lock(&port->mutex);
2092
2093 tty_dev = device_find_child(uport->dev, &match, serial_match_port);
2094 if (tty_dev && device_may_wakeup(tty_dev)) {
2095 enable_irq_wake(uport->irq);
2096 put_device(tty_dev);
2097 mutex_unlock(&port->mutex);
2098 return 0;
2099 }
2100 put_device(tty_dev);
2101
2102 /* Nothing to do if the console is not suspending */
2103 if (!console_suspend_enabled && uart_console(uport))
2104 goto unlock;
2105
2106 uport->suspended = 1;
2107
2108 if (tty_port_initialized(port)) {
2109 const struct uart_ops *ops = uport->ops;
2110 int tries;
2111
2112 tty_port_set_suspended(port, 1);
2113 tty_port_set_initialized(port, 0);
2114
2115 spin_lock_irq(&uport->lock);
2116 ops->stop_tx(uport);
2117 ops->set_mctrl(uport, 0);
2118 ops->stop_rx(uport);
2119 spin_unlock_irq(&uport->lock);
2120
2121 /*
2122 * Wait for the transmitter to empty.
2123 */
2124 for (tries = 3; !ops->tx_empty(uport) && tries; tries--)
2125 msleep(10);
2126 if (!tries)
2127 dev_err(uport->dev, "%s: Unable to drain transmitter\n",
2128 uport->name);
2129
2130 ops->shutdown(uport);
2131 }
2132
2133 /*
2134 * Disable the console device before suspending.
2135 */
2136 if (uart_console(uport))
2137 console_stop(uport->cons);
2138
2139 uart_change_pm(state, UART_PM_STATE_OFF);
2140unlock:
2141 mutex_unlock(&port->mutex);
2142
2143 return 0;
2144}
2145
2146int uart_resume_port(struct uart_driver *drv, struct uart_port *uport)
2147{
2148 struct uart_state *state = drv->state + uport->line;
2149 struct tty_port *port = &state->port;
2150 struct device *tty_dev;
2151 struct uart_match match = {uport, drv};
2152 struct ktermios termios;
2153
2154 mutex_lock(&port->mutex);
2155
2156 tty_dev = device_find_child(uport->dev, &match, serial_match_port);
2157 if (!uport->suspended && device_may_wakeup(tty_dev)) {
2158 if (irqd_is_wakeup_set(irq_get_irq_data((uport->irq))))
2159 disable_irq_wake(uport->irq);
2160 put_device(tty_dev);
2161 mutex_unlock(&port->mutex);
2162 return 0;
2163 }
2164 put_device(tty_dev);
2165 uport->suspended = 0;
2166
2167 /*
2168 * Re-enable the console device after suspending.
2169 */
2170 if (uart_console(uport)) {
2171 /*
2172 * First try to use the console cflag setting.
2173 */
2174 memset(&termios, 0, sizeof(struct ktermios));
2175 termios.c_cflag = uport->cons->cflag;
2176
2177 /*
2178 * If that's unset, use the tty termios setting.
2179 */
2180 if (port->tty && termios.c_cflag == 0)
2181 termios = port->tty->termios;
2182
2183 if (console_suspend_enabled)
2184 uart_change_pm(state, UART_PM_STATE_ON);
2185 uport->ops->set_termios(uport, &termios, NULL);
2186 if (console_suspend_enabled)
2187 console_start(uport->cons);
2188 }
2189
2190 if (tty_port_suspended(port)) {
2191 const struct uart_ops *ops = uport->ops;
2192 int ret;
2193
2194 uart_change_pm(state, UART_PM_STATE_ON);
2195 spin_lock_irq(&uport->lock);
2196 ops->set_mctrl(uport, 0);
2197 spin_unlock_irq(&uport->lock);
2198 if (console_suspend_enabled || !uart_console(uport)) {
2199 /* Protected by port mutex for now */
2200 struct tty_struct *tty = port->tty;
2201 ret = ops->startup(uport);
2202 if (ret == 0) {
2203 if (tty)
2204 uart_change_speed(tty, state, NULL);
2205 spin_lock_irq(&uport->lock);
2206 ops->set_mctrl(uport, uport->mctrl);
2207 ops->start_tx(uport);
2208 spin_unlock_irq(&uport->lock);
2209 tty_port_set_initialized(port, 1);
2210 } else {
2211 /*
2212 * Failed to resume - maybe hardware went away?
2213 * Clear the "initialized" flag so we won't try
2214 * to call the low level drivers shutdown method.
2215 */
2216 uart_shutdown(tty, state);
2217 }
2218 }
2219
2220 tty_port_set_suspended(port, 0);
2221 }
2222
2223 mutex_unlock(&port->mutex);
2224
2225 return 0;
2226}
2227
2228static inline void
2229uart_report_port(struct uart_driver *drv, struct uart_port *port)
2230{
2231 char address[64];
2232
2233 switch (port->iotype) {
2234 case UPIO_PORT:
2235 snprintf(address, sizeof(address), "I/O 0x%lx", port->iobase);
2236 break;
2237 case UPIO_HUB6:
2238 snprintf(address, sizeof(address),
2239 "I/O 0x%lx offset 0x%x", port->iobase, port->hub6);
2240 break;
2241 case UPIO_MEM:
2242 case UPIO_MEM16:
2243 case UPIO_MEM32:
2244 case UPIO_MEM32BE:
2245 case UPIO_AU:
2246 case UPIO_TSI:
2247 snprintf(address, sizeof(address),
2248 "MMIO 0x%llx", (unsigned long long)port->mapbase);
2249 break;
2250 default:
2251 strlcpy(address, "*unknown*", sizeof(address));
2252 break;
2253 }
2254
2255 pr_info("%s%s%s at %s (irq = %d, base_baud = %d) is a %s\n",
2256 port->dev ? dev_name(port->dev) : "",
2257 port->dev ? ": " : "",
2258 port->name,
2259 address, port->irq, port->uartclk / 16, uart_type(port));
2260}
2261
2262static void
2263uart_configure_port(struct uart_driver *drv, struct uart_state *state,
2264 struct uart_port *port)
2265{
2266 unsigned int flags;
2267
2268 /*
2269 * If there isn't a port here, don't do anything further.
2270 */
2271 if (!port->iobase && !port->mapbase && !port->membase)
2272 return;
2273
2274 /*
2275 * Now do the auto configuration stuff. Note that config_port
2276 * is expected to claim the resources and map the port for us.
2277 */
2278 flags = 0;
2279 if (port->flags & UPF_AUTO_IRQ)
2280 flags |= UART_CONFIG_IRQ;
2281 if (port->flags & UPF_BOOT_AUTOCONF) {
2282 if (!(port->flags & UPF_FIXED_TYPE)) {
2283 port->type = PORT_UNKNOWN;
2284 flags |= UART_CONFIG_TYPE;
2285 }
2286 port->ops->config_port(port, flags);
2287 }
2288
2289 if (port->type != PORT_UNKNOWN) {
2290 unsigned long flags;
2291
2292 uart_report_port(drv, port);
2293
2294 /* Power up port for set_mctrl() */
2295 uart_change_pm(state, UART_PM_STATE_ON);
2296
2297 /*
2298 * Ensure that the modem control lines are de-activated.
2299 * keep the DTR setting that is set in uart_set_options()
2300 * We probably don't need a spinlock around this, but
2301 */
2302 spin_lock_irqsave(&port->lock, flags);
2303 port->ops->set_mctrl(port, port->mctrl & TIOCM_DTR);
2304 spin_unlock_irqrestore(&port->lock, flags);
2305
2306 /*
2307 * If this driver supports console, and it hasn't been
2308 * successfully registered yet, try to re-register it.
2309 * It may be that the port was not available.
2310 */
2311 if (port->cons && !(port->cons->flags & CON_ENABLED))
2312 register_console(port->cons);
2313
2314 /*
2315 * Power down all ports by default, except the
2316 * console if we have one.
2317 */
2318 if (!uart_console(port))
2319 uart_change_pm(state, UART_PM_STATE_OFF);
2320 }
2321}
2322
2323#ifdef CONFIG_CONSOLE_POLL
2324
2325static int uart_poll_init(struct tty_driver *driver, int line, char *options)
2326{
2327 struct uart_driver *drv = driver->driver_state;
2328 struct uart_state *state = drv->state + line;
2329 struct tty_port *tport;
2330 struct uart_port *port;
2331 int baud = 9600;
2332 int bits = 8;
2333 int parity = 'n';
2334 int flow = 'n';
2335 int ret = 0;
2336
2337 tport = &state->port;
2338 mutex_lock(&tport->mutex);
2339
2340 port = uart_port_check(state);
2341 if (!port || !(port->ops->poll_get_char && port->ops->poll_put_char)) {
2342 ret = -1;
2343 goto out;
2344 }
2345
2346 if (port->ops->poll_init) {
2347 /*
2348 * We don't set initialized as we only initialized the hw,
2349 * e.g. state->xmit is still uninitialized.
2350 */
2351 if (!tty_port_initialized(tport))
2352 ret = port->ops->poll_init(port);
2353 }
2354
2355 if (!ret && options) {
2356 uart_parse_options(options, &baud, &parity, &bits, &flow);
2357 ret = uart_set_options(port, NULL, baud, parity, bits, flow);
2358 }
2359out:
2360 mutex_unlock(&tport->mutex);
2361 return ret;
2362}
2363
2364static int uart_poll_get_char(struct tty_driver *driver, int line)
2365{
2366 struct uart_driver *drv = driver->driver_state;
2367 struct uart_state *state = drv->state + line;
2368 struct uart_port *port;
2369 int ret = -1;
2370
2371 port = uart_port_ref(state);
2372 if (port) {
2373 ret = port->ops->poll_get_char(port);
2374 uart_port_deref(port);
2375 }
2376
2377 return ret;
2378}
2379
2380static void uart_poll_put_char(struct tty_driver *driver, int line, char ch)
2381{
2382 struct uart_driver *drv = driver->driver_state;
2383 struct uart_state *state = drv->state + line;
2384 struct uart_port *port;
2385
2386 port = uart_port_ref(state);
2387 if (!port)
2388 return;
2389
2390 if (ch == '\n')
2391 port->ops->poll_put_char(port, '\r');
2392 port->ops->poll_put_char(port, ch);
2393 uart_port_deref(port);
2394}
2395#endif
2396
2397static const struct tty_operations uart_ops = {
2398 .open = uart_open,
2399 .close = uart_close,
2400 .write = uart_write,
2401 .put_char = uart_put_char,
2402 .flush_chars = uart_flush_chars,
2403 .write_room = uart_write_room,
2404 .chars_in_buffer= uart_chars_in_buffer,
2405 .flush_buffer = uart_flush_buffer,
2406 .ioctl = uart_ioctl,
2407 .throttle = uart_throttle,
2408 .unthrottle = uart_unthrottle,
2409 .send_xchar = uart_send_xchar,
2410 .set_termios = uart_set_termios,
2411 .set_ldisc = uart_set_ldisc,
2412 .stop = uart_stop,
2413 .start = uart_start,
2414 .hangup = uart_hangup,
2415 .break_ctl = uart_break_ctl,
2416 .wait_until_sent= uart_wait_until_sent,
2417#ifdef CONFIG_PROC_FS
2418 .proc_fops = &uart_proc_fops,
2419#endif
2420 .tiocmget = uart_tiocmget,
2421 .tiocmset = uart_tiocmset,
2422 .get_icount = uart_get_icount,
2423#ifdef CONFIG_CONSOLE_POLL
2424 .poll_init = uart_poll_init,
2425 .poll_get_char = uart_poll_get_char,
2426 .poll_put_char = uart_poll_put_char,
2427#endif
2428};
2429
2430static const struct tty_port_operations uart_port_ops = {
2431 .carrier_raised = uart_carrier_raised,
2432 .dtr_rts = uart_dtr_rts,
2433 .activate = uart_port_activate,
2434 .shutdown = uart_tty_port_shutdown,
2435};
2436
2437/**
2438 * uart_register_driver - register a driver with the uart core layer
2439 * @drv: low level driver structure
2440 *
2441 * Register a uart driver with the core driver. We in turn register
2442 * with the tty layer, and initialise the core driver per-port state.
2443 *
2444 * We have a proc file in /proc/tty/driver which is named after the
2445 * normal driver.
2446 *
2447 * drv->port should be NULL, and the per-port structures should be
2448 * registered using uart_add_one_port after this call has succeeded.
2449 */
2450int uart_register_driver(struct uart_driver *drv)
2451{
2452 struct tty_driver *normal;
2453 int i, retval;
2454
2455 BUG_ON(drv->state);
2456
2457 /*
2458 * Maybe we should be using a slab cache for this, especially if
2459 * we have a large number of ports to handle.
2460 */
2461 drv->state = kzalloc(sizeof(struct uart_state) * drv->nr, GFP_KERNEL);
2462 if (!drv->state)
2463 goto out;
2464
2465 normal = alloc_tty_driver(drv->nr);
2466 if (!normal)
2467 goto out_kfree;
2468
2469 drv->tty_driver = normal;
2470
2471 normal->driver_name = drv->driver_name;
2472 normal->name = drv->dev_name;
2473 normal->major = drv->major;
2474 normal->minor_start = drv->minor;
2475 normal->type = TTY_DRIVER_TYPE_SERIAL;
2476 normal->subtype = SERIAL_TYPE_NORMAL;
2477 normal->init_termios = tty_std_termios;
2478 normal->init_termios.c_cflag = B9600 | CS8 | CREAD | HUPCL | CLOCAL;
2479 normal->init_termios.c_ispeed = normal->init_termios.c_ospeed = 9600;
2480 normal->flags = TTY_DRIVER_REAL_RAW | TTY_DRIVER_DYNAMIC_DEV;
2481 normal->driver_state = drv;
2482 tty_set_operations(normal, &uart_ops);
2483
2484 /*
2485 * Initialise the UART state(s).
2486 */
2487 for (i = 0; i < drv->nr; i++) {
2488 struct uart_state *state = drv->state + i;
2489 struct tty_port *port = &state->port;
2490
2491 tty_port_init(port);
2492 port->ops = &uart_port_ops;
2493 }
2494
2495 retval = tty_register_driver(normal);
2496 if (retval >= 0)
2497 return retval;
2498
2499 for (i = 0; i < drv->nr; i++)
2500 tty_port_destroy(&drv->state[i].port);
2501 put_tty_driver(normal);
2502out_kfree:
2503 kfree(drv->state);
2504out:
2505 return -ENOMEM;
2506}
2507
2508/**
2509 * uart_unregister_driver - remove a driver from the uart core layer
2510 * @drv: low level driver structure
2511 *
2512 * Remove all references to a driver from the core driver. The low
2513 * level driver must have removed all its ports via the
2514 * uart_remove_one_port() if it registered them with uart_add_one_port().
2515 * (ie, drv->port == NULL)
2516 */
2517void uart_unregister_driver(struct uart_driver *drv)
2518{
2519 struct tty_driver *p = drv->tty_driver;
2520 unsigned int i;
2521
2522 tty_unregister_driver(p);
2523 put_tty_driver(p);
2524 for (i = 0; i < drv->nr; i++)
2525 tty_port_destroy(&drv->state[i].port);
2526 kfree(drv->state);
2527 drv->state = NULL;
2528 drv->tty_driver = NULL;
2529}
2530
2531struct tty_driver *uart_console_device(struct console *co, int *index)
2532{
2533 struct uart_driver *p = co->data;
2534 *index = co->index;
2535 return p->tty_driver;
2536}
2537
2538static ssize_t uart_get_attr_uartclk(struct device *dev,
2539 struct device_attribute *attr, char *buf)
2540{
2541 struct serial_struct tmp;
2542 struct tty_port *port = dev_get_drvdata(dev);
2543
2544 uart_get_info(port, &tmp);
2545 return snprintf(buf, PAGE_SIZE, "%d\n", tmp.baud_base * 16);
2546}
2547
2548static ssize_t uart_get_attr_type(struct device *dev,
2549 struct device_attribute *attr, char *buf)
2550{
2551 struct serial_struct tmp;
2552 struct tty_port *port = dev_get_drvdata(dev);
2553
2554 uart_get_info(port, &tmp);
2555 return snprintf(buf, PAGE_SIZE, "%d\n", tmp.type);
2556}
2557static ssize_t uart_get_attr_line(struct device *dev,
2558 struct device_attribute *attr, char *buf)
2559{
2560 struct serial_struct tmp;
2561 struct tty_port *port = dev_get_drvdata(dev);
2562
2563 uart_get_info(port, &tmp);
2564 return snprintf(buf, PAGE_SIZE, "%d\n", tmp.line);
2565}
2566
2567static ssize_t uart_get_attr_port(struct device *dev,
2568 struct device_attribute *attr, char *buf)
2569{
2570 struct serial_struct tmp;
2571 struct tty_port *port = dev_get_drvdata(dev);
2572 unsigned long ioaddr;
2573
2574 uart_get_info(port, &tmp);
2575 ioaddr = tmp.port;
2576 if (HIGH_BITS_OFFSET)
2577 ioaddr |= (unsigned long)tmp.port_high << HIGH_BITS_OFFSET;
2578 return snprintf(buf, PAGE_SIZE, "0x%lX\n", ioaddr);
2579}
2580
2581static ssize_t uart_get_attr_irq(struct device *dev,
2582 struct device_attribute *attr, char *buf)
2583{
2584 struct serial_struct tmp;
2585 struct tty_port *port = dev_get_drvdata(dev);
2586
2587 uart_get_info(port, &tmp);
2588 return snprintf(buf, PAGE_SIZE, "%d\n", tmp.irq);
2589}
2590
2591static ssize_t uart_get_attr_flags(struct device *dev,
2592 struct device_attribute *attr, char *buf)
2593{
2594 struct serial_struct tmp;
2595 struct tty_port *port = dev_get_drvdata(dev);
2596
2597 uart_get_info(port, &tmp);
2598 return snprintf(buf, PAGE_SIZE, "0x%X\n", tmp.flags);
2599}
2600
2601static ssize_t uart_get_attr_xmit_fifo_size(struct device *dev,
2602 struct device_attribute *attr, char *buf)
2603{
2604 struct serial_struct tmp;
2605 struct tty_port *port = dev_get_drvdata(dev);
2606
2607 uart_get_info(port, &tmp);
2608 return snprintf(buf, PAGE_SIZE, "%d\n", tmp.xmit_fifo_size);
2609}
2610
2611
2612static ssize_t uart_get_attr_close_delay(struct device *dev,
2613 struct device_attribute *attr, char *buf)
2614{
2615 struct serial_struct tmp;
2616 struct tty_port *port = dev_get_drvdata(dev);
2617
2618 uart_get_info(port, &tmp);
2619 return snprintf(buf, PAGE_SIZE, "%d\n", tmp.close_delay);
2620}
2621
2622
2623static ssize_t uart_get_attr_closing_wait(struct device *dev,
2624 struct device_attribute *attr, char *buf)
2625{
2626 struct serial_struct tmp;
2627 struct tty_port *port = dev_get_drvdata(dev);
2628
2629 uart_get_info(port, &tmp);
2630 return snprintf(buf, PAGE_SIZE, "%d\n", tmp.closing_wait);
2631}
2632
2633static ssize_t uart_get_attr_custom_divisor(struct device *dev,
2634 struct device_attribute *attr, char *buf)
2635{
2636 struct serial_struct tmp;
2637 struct tty_port *port = dev_get_drvdata(dev);
2638
2639 uart_get_info(port, &tmp);
2640 return snprintf(buf, PAGE_SIZE, "%d\n", tmp.custom_divisor);
2641}
2642
2643static ssize_t uart_get_attr_io_type(struct device *dev,
2644 struct device_attribute *attr, char *buf)
2645{
2646 struct serial_struct tmp;
2647 struct tty_port *port = dev_get_drvdata(dev);
2648
2649 uart_get_info(port, &tmp);
2650 return snprintf(buf, PAGE_SIZE, "%d\n", tmp.io_type);
2651}
2652
2653static ssize_t uart_get_attr_iomem_base(struct device *dev,
2654 struct device_attribute *attr, char *buf)
2655{
2656 struct serial_struct tmp;
2657 struct tty_port *port = dev_get_drvdata(dev);
2658
2659 uart_get_info(port, &tmp);
2660 return snprintf(buf, PAGE_SIZE, "0x%lX\n", (unsigned long)tmp.iomem_base);
2661}
2662
2663static ssize_t uart_get_attr_iomem_reg_shift(struct device *dev,
2664 struct device_attribute *attr, char *buf)
2665{
2666 struct serial_struct tmp;
2667 struct tty_port *port = dev_get_drvdata(dev);
2668
2669 uart_get_info(port, &tmp);
2670 return snprintf(buf, PAGE_SIZE, "%d\n", tmp.iomem_reg_shift);
2671}
2672
2673static DEVICE_ATTR(type, S_IRUSR | S_IRGRP, uart_get_attr_type, NULL);
2674static DEVICE_ATTR(line, S_IRUSR | S_IRGRP, uart_get_attr_line, NULL);
2675static DEVICE_ATTR(port, S_IRUSR | S_IRGRP, uart_get_attr_port, NULL);
2676static DEVICE_ATTR(irq, S_IRUSR | S_IRGRP, uart_get_attr_irq, NULL);
2677static DEVICE_ATTR(flags, S_IRUSR | S_IRGRP, uart_get_attr_flags, NULL);
2678static DEVICE_ATTR(xmit_fifo_size, S_IRUSR | S_IRGRP, uart_get_attr_xmit_fifo_size, NULL);
2679static DEVICE_ATTR(uartclk, S_IRUSR | S_IRGRP, uart_get_attr_uartclk, NULL);
2680static DEVICE_ATTR(close_delay, S_IRUSR | S_IRGRP, uart_get_attr_close_delay, NULL);
2681static DEVICE_ATTR(closing_wait, S_IRUSR | S_IRGRP, uart_get_attr_closing_wait, NULL);
2682static DEVICE_ATTR(custom_divisor, S_IRUSR | S_IRGRP, uart_get_attr_custom_divisor, NULL);
2683static DEVICE_ATTR(io_type, S_IRUSR | S_IRGRP, uart_get_attr_io_type, NULL);
2684static DEVICE_ATTR(iomem_base, S_IRUSR | S_IRGRP, uart_get_attr_iomem_base, NULL);
2685static DEVICE_ATTR(iomem_reg_shift, S_IRUSR | S_IRGRP, uart_get_attr_iomem_reg_shift, NULL);
2686
2687static struct attribute *tty_dev_attrs[] = {
2688 &dev_attr_type.attr,
2689 &dev_attr_line.attr,
2690 &dev_attr_port.attr,
2691 &dev_attr_irq.attr,
2692 &dev_attr_flags.attr,
2693 &dev_attr_xmit_fifo_size.attr,
2694 &dev_attr_uartclk.attr,
2695 &dev_attr_close_delay.attr,
2696 &dev_attr_closing_wait.attr,
2697 &dev_attr_custom_divisor.attr,
2698 &dev_attr_io_type.attr,
2699 &dev_attr_iomem_base.attr,
2700 &dev_attr_iomem_reg_shift.attr,
2701 NULL,
2702 };
2703
2704static const struct attribute_group tty_dev_attr_group = {
2705 .attrs = tty_dev_attrs,
2706 };
2707
2708/**
2709 * uart_add_one_port - attach a driver-defined port structure
2710 * @drv: pointer to the uart low level driver structure for this port
2711 * @uport: uart port structure to use for this port.
2712 *
2713 * This allows the driver to register its own uart_port structure
2714 * with the core driver. The main purpose is to allow the low
2715 * level uart drivers to expand uart_port, rather than having yet
2716 * more levels of structures.
2717 */
2718int uart_add_one_port(struct uart_driver *drv, struct uart_port *uport)
2719{
2720 struct uart_state *state;
2721 struct tty_port *port;
2722 int ret = 0;
2723 struct device *tty_dev;
2724 int num_groups;
2725
2726 BUG_ON(in_interrupt());
2727
2728 if (uport->line >= drv->nr)
2729 return -EINVAL;
2730
2731 state = drv->state + uport->line;
2732 port = &state->port;
2733
2734 mutex_lock(&port_mutex);
2735 mutex_lock(&port->mutex);
2736 if (state->uart_port) {
2737 ret = -EINVAL;
2738 goto out;
2739 }
2740
2741 /* Link the port to the driver state table and vice versa */
2742 atomic_set(&state->refcount, 1);
2743 init_waitqueue_head(&state->remove_wait);
2744 state->uart_port = uport;
2745 uport->state = state;
2746
2747 state->pm_state = UART_PM_STATE_UNDEFINED;
2748 uport->cons = drv->cons;
2749 uport->minor = drv->tty_driver->minor_start + uport->line;
2750 uport->name = kasprintf(GFP_KERNEL, "%s%d", drv->dev_name,
2751 drv->tty_driver->name_base + uport->line);
2752 if (!uport->name) {
2753 ret = -ENOMEM;
2754 goto out;
2755 }
2756
2757 /*
2758 * If this port is a console, then the spinlock is already
2759 * initialised.
2760 */
2761 if (!(uart_console(uport) && (uport->cons->flags & CON_ENABLED))) {
2762 spin_lock_init(&uport->lock);
2763 lockdep_set_class(&uport->lock, &port_lock_key);
2764 }
2765 if (uport->cons && uport->dev)
2766 of_console_check(uport->dev->of_node, uport->cons->name, uport->line);
2767
2768 uart_configure_port(drv, state, uport);
2769
2770 port->console = uart_console(uport);
2771
2772 num_groups = 2;
2773 if (uport->attr_group)
2774 num_groups++;
2775
2776 uport->tty_groups = kcalloc(num_groups, sizeof(*uport->tty_groups),
2777 GFP_KERNEL);
2778 if (!uport->tty_groups) {
2779 ret = -ENOMEM;
2780 goto out;
2781 }
2782 uport->tty_groups[0] = &tty_dev_attr_group;
2783 if (uport->attr_group)
2784 uport->tty_groups[1] = uport->attr_group;
2785
2786 /*
2787 * Register the port whether it's detected or not. This allows
2788 * setserial to be used to alter this port's parameters.
2789 */
2790 tty_dev = tty_port_register_device_attr_serdev(port, drv->tty_driver,
2791 uport->line, uport->dev, port, uport->tty_groups);
2792 if (likely(!IS_ERR(tty_dev))) {
2793 device_set_wakeup_capable(tty_dev, 1);
2794 } else {
2795 dev_err(uport->dev, "Cannot register tty device on line %d\n",
2796 uport->line);
2797 }
2798
2799 /*
2800 * Ensure UPF_DEAD is not set.
2801 */
2802 uport->flags &= ~UPF_DEAD;
2803
2804 out:
2805 mutex_unlock(&port->mutex);
2806 mutex_unlock(&port_mutex);
2807
2808 return ret;
2809}
2810
2811/**
2812 * uart_remove_one_port - detach a driver defined port structure
2813 * @drv: pointer to the uart low level driver structure for this port
2814 * @uport: uart port structure for this port
2815 *
2816 * This unhooks (and hangs up) the specified port structure from the
2817 * core driver. No further calls will be made to the low-level code
2818 * for this port.
2819 */
2820int uart_remove_one_port(struct uart_driver *drv, struct uart_port *uport)
2821{
2822 struct uart_state *state = drv->state + uport->line;
2823 struct tty_port *port = &state->port;
2824 struct uart_port *uart_port;
2825 struct tty_struct *tty;
2826 int ret = 0;
2827
2828 BUG_ON(in_interrupt());
2829
2830 mutex_lock(&port_mutex);
2831
2832 /*
2833 * Mark the port "dead" - this prevents any opens from
2834 * succeeding while we shut down the port.
2835 */
2836 mutex_lock(&port->mutex);
2837 uart_port = uart_port_check(state);
2838 if (uart_port != uport)
2839 dev_alert(uport->dev, "Removing wrong port: %p != %p\n",
2840 uart_port, uport);
2841
2842 if (!uart_port) {
2843 mutex_unlock(&port->mutex);
2844 ret = -EINVAL;
2845 goto out;
2846 }
2847 uport->flags |= UPF_DEAD;
2848 mutex_unlock(&port->mutex);
2849
2850 /*
2851 * Remove the devices from the tty layer
2852 */
2853 tty_port_unregister_device(port, drv->tty_driver, uport->line);
2854
2855 tty = tty_port_tty_get(port);
2856 if (tty) {
2857 tty_vhangup(port->tty);
2858 tty_kref_put(tty);
2859 }
2860
2861 /*
2862 * If the port is used as a console, unregister it
2863 */
2864 if (uart_console(uport))
2865 unregister_console(uport->cons);
2866
2867 /*
2868 * Free the port IO and memory resources, if any.
2869 */
2870 if (uport->type != PORT_UNKNOWN && uport->ops->release_port)
2871 uport->ops->release_port(uport);
2872 kfree(uport->tty_groups);
2873 kfree(uport->name);
2874
2875 /*
2876 * Indicate that there isn't a port here anymore.
2877 */
2878 uport->type = PORT_UNKNOWN;
2879
2880 mutex_lock(&port->mutex);
2881 WARN_ON(atomic_dec_return(&state->refcount) < 0);
2882 wait_event(state->remove_wait, !atomic_read(&state->refcount));
2883 state->uart_port = NULL;
2884 mutex_unlock(&port->mutex);
2885out:
2886 mutex_unlock(&port_mutex);
2887
2888 return ret;
2889}
2890
2891/*
2892 * Are the two ports equivalent?
2893 */
2894int uart_match_port(struct uart_port *port1, struct uart_port *port2)
2895{
2896 if (port1->iotype != port2->iotype)
2897 return 0;
2898
2899 switch (port1->iotype) {
2900 case UPIO_PORT:
2901 return (port1->iobase == port2->iobase);
2902 case UPIO_HUB6:
2903 return (port1->iobase == port2->iobase) &&
2904 (port1->hub6 == port2->hub6);
2905 case UPIO_MEM:
2906 case UPIO_MEM16:
2907 case UPIO_MEM32:
2908 case UPIO_MEM32BE:
2909 case UPIO_AU:
2910 case UPIO_TSI:
2911 return (port1->mapbase == port2->mapbase);
2912 }
2913 return 0;
2914}
2915EXPORT_SYMBOL(uart_match_port);
2916
2917/**
2918 * uart_handle_dcd_change - handle a change of carrier detect state
2919 * @uport: uart_port structure for the open port
2920 * @status: new carrier detect status, nonzero if active
2921 *
2922 * Caller must hold uport->lock
2923 */
2924void uart_handle_dcd_change(struct uart_port *uport, unsigned int status)
2925{
2926 struct tty_port *port = &uport->state->port;
2927 struct tty_struct *tty = port->tty;
2928 struct tty_ldisc *ld;
2929
2930 lockdep_assert_held_once(&uport->lock);
2931
2932 if (tty) {
2933 ld = tty_ldisc_ref(tty);
2934 if (ld) {
2935 if (ld->ops->dcd_change)
2936 ld->ops->dcd_change(tty, status);
2937 tty_ldisc_deref(ld);
2938 }
2939 }
2940
2941 uport->icount.dcd++;
2942
2943 if (uart_dcd_enabled(uport)) {
2944 if (status)
2945 wake_up_interruptible(&port->open_wait);
2946 else if (tty)
2947 tty_hangup(tty);
2948 }
2949}
2950EXPORT_SYMBOL_GPL(uart_handle_dcd_change);
2951
2952/**
2953 * uart_handle_cts_change - handle a change of clear-to-send state
2954 * @uport: uart_port structure for the open port
2955 * @status: new clear to send status, nonzero if active
2956 *
2957 * Caller must hold uport->lock
2958 */
2959void uart_handle_cts_change(struct uart_port *uport, unsigned int status)
2960{
2961 lockdep_assert_held_once(&uport->lock);
2962
2963 uport->icount.cts++;
2964
2965 if (uart_softcts_mode(uport)) {
2966 if (uport->hw_stopped) {
2967 if (status) {
2968 uport->hw_stopped = 0;
2969 uport->ops->start_tx(uport);
2970 uart_write_wakeup(uport);
2971 }
2972 } else {
2973 if (!status) {
2974 uport->hw_stopped = 1;
2975 uport->ops->stop_tx(uport);
2976 }
2977 }
2978
2979 }
2980}
2981EXPORT_SYMBOL_GPL(uart_handle_cts_change);
2982
2983/**
2984 * uart_insert_char - push a char to the uart layer
2985 *
2986 * User is responsible to call tty_flip_buffer_push when they are done with
2987 * insertion.
2988 *
2989 * @port: corresponding port
2990 * @status: state of the serial port RX buffer (LSR for 8250)
2991 * @overrun: mask of overrun bits in @status
2992 * @ch: character to push
2993 * @flag: flag for the character (see TTY_NORMAL and friends)
2994 */
2995void uart_insert_char(struct uart_port *port, unsigned int status,
2996 unsigned int overrun, unsigned int ch, unsigned int flag)
2997{
2998 struct tty_port *tport = &port->state->port;
2999
3000 if ((status & port->ignore_status_mask & ~overrun) == 0)
3001 if (tty_insert_flip_char(tport, ch, flag) == 0)
3002 ++port->icount.buf_overrun;
3003
3004 /*
3005 * Overrun is special. Since it's reported immediately,
3006 * it doesn't affect the current character.
3007 */
3008 if (status & ~port->ignore_status_mask & overrun)
3009 if (tty_insert_flip_char(tport, 0, TTY_OVERRUN) == 0)
3010 ++port->icount.buf_overrun;
3011}
3012EXPORT_SYMBOL_GPL(uart_insert_char);
3013
3014EXPORT_SYMBOL(uart_write_wakeup);
3015EXPORT_SYMBOL(uart_register_driver);
3016EXPORT_SYMBOL(uart_unregister_driver);
3017EXPORT_SYMBOL(uart_suspend_port);
3018EXPORT_SYMBOL(uart_resume_port);
3019EXPORT_SYMBOL(uart_add_one_port);
3020EXPORT_SYMBOL(uart_remove_one_port);
3021
3022/**
3023 * uart_get_rs485_mode() - retrieve rs485 properties for given uart
3024 * @dev: uart device
3025 * @rs485conf: output parameter
3026 *
3027 * This function implements the device tree binding described in
3028 * Documentation/devicetree/bindings/serial/rs485.txt.
3029 */
3030void uart_get_rs485_mode(struct device *dev, struct serial_rs485 *rs485conf)
3031{
3032 u32 rs485_delay[2];
3033 int ret;
3034
3035 ret = device_property_read_u32_array(dev, "rs485-rts-delay",
3036 rs485_delay, 2);
3037 if (!ret) {
3038 rs485conf->delay_rts_before_send = rs485_delay[0];
3039 rs485conf->delay_rts_after_send = rs485_delay[1];
3040 } else {
3041 rs485conf->delay_rts_before_send = 0;
3042 rs485conf->delay_rts_after_send = 0;
3043 }
3044
3045 /*
3046 * Clear full-duplex and enabled flags, set RTS polarity to active high
3047 * to get to a defined state with the following properties:
3048 */
3049 rs485conf->flags &= ~(SER_RS485_RX_DURING_TX | SER_RS485_ENABLED |
3050 SER_RS485_RTS_AFTER_SEND);
3051 rs485conf->flags |= SER_RS485_RTS_ON_SEND;
3052
3053 if (device_property_read_bool(dev, "rs485-rx-during-tx"))
3054 rs485conf->flags |= SER_RS485_RX_DURING_TX;
3055
3056 if (device_property_read_bool(dev, "linux,rs485-enabled-at-boot-time"))
3057 rs485conf->flags |= SER_RS485_ENABLED;
3058
3059 if (device_property_read_bool(dev, "rs485-rts-active-low")) {
3060 rs485conf->flags &= ~SER_RS485_RTS_ON_SEND;
3061 rs485conf->flags |= SER_RS485_RTS_AFTER_SEND;
3062 }
3063}
3064EXPORT_SYMBOL_GPL(uart_get_rs485_mode);
3065
3066MODULE_DESCRIPTION("Serial driver core");
3067MODULE_LICENSE("GPL");
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/kernel.h>
19#include <linux/of.h>
20#include <linux/pm_runtime.h>
21#include <linux/proc_fs.h>
22#include <linux/seq_file.h>
23#include <linux/device.h>
24#include <linux/serial.h> /* for serial_state and serial_icounter_struct */
25#include <linux/serial_core.h>
26#include <linux/sysrq.h>
27#include <linux/delay.h>
28#include <linux/mutex.h>
29#include <linux/math64.h>
30#include <linux/security.h>
31
32#include <linux/irq.h>
33#include <linux/uaccess.h>
34
35#include "serial_base.h"
36
37/*
38 * This is used to lock changes in serial line configuration.
39 */
40static DEFINE_MUTEX(port_mutex);
41
42/*
43 * lockdep: port->lock is initialized in two places, but we
44 * want only one lock-class:
45 */
46static struct lock_class_key port_lock_key;
47
48#define HIGH_BITS_OFFSET ((sizeof(long)-sizeof(int))*8)
49
50/*
51 * Max time with active RTS before/after data is sent.
52 */
53#define RS485_MAX_RTS_DELAY 100 /* msecs */
54
55static void uart_change_pm(struct uart_state *state,
56 enum uart_pm_state pm_state);
57
58static void uart_port_shutdown(struct tty_port *port);
59
60static int uart_dcd_enabled(struct uart_port *uport)
61{
62 return !!(uport->status & UPSTAT_DCD_ENABLE);
63}
64
65static inline struct uart_port *uart_port_ref(struct uart_state *state)
66{
67 if (atomic_add_unless(&state->refcount, 1, 0))
68 return state->uart_port;
69 return NULL;
70}
71
72static inline void uart_port_deref(struct uart_port *uport)
73{
74 if (atomic_dec_and_test(&uport->state->refcount))
75 wake_up(&uport->state->remove_wait);
76}
77
78#define uart_port_lock(state, flags) \
79 ({ \
80 struct uart_port *__uport = uart_port_ref(state); \
81 if (__uport) \
82 uart_port_lock_irqsave(__uport, &flags); \
83 __uport; \
84 })
85
86#define uart_port_unlock(uport, flags) \
87 ({ \
88 struct uart_port *__uport = uport; \
89 if (__uport) { \
90 uart_port_unlock_irqrestore(__uport, flags); \
91 uart_port_deref(__uport); \
92 } \
93 })
94
95static inline struct uart_port *uart_port_check(struct uart_state *state)
96{
97 lockdep_assert_held(&state->port.mutex);
98 return state->uart_port;
99}
100
101/**
102 * uart_write_wakeup - schedule write processing
103 * @port: port to be processed
104 *
105 * This routine is used by the interrupt handler to schedule processing in the
106 * software interrupt portion of the driver. A driver is expected to call this
107 * function when the number of characters in the transmit buffer have dropped
108 * below a threshold.
109 *
110 * Locking: @port->lock should be held
111 */
112void uart_write_wakeup(struct uart_port *port)
113{
114 struct uart_state *state = port->state;
115 /*
116 * This means you called this function _after_ the port was
117 * closed. No cookie for you.
118 */
119 BUG_ON(!state);
120 tty_port_tty_wakeup(&state->port);
121}
122EXPORT_SYMBOL(uart_write_wakeup);
123
124static void uart_stop(struct tty_struct *tty)
125{
126 struct uart_state *state = tty->driver_data;
127 struct uart_port *port;
128 unsigned long flags;
129
130 port = uart_port_lock(state, flags);
131 if (port)
132 port->ops->stop_tx(port);
133 uart_port_unlock(port, flags);
134}
135
136static void __uart_start(struct uart_state *state)
137{
138 struct uart_port *port = state->uart_port;
139 struct serial_port_device *port_dev;
140 int err;
141
142 if (!port || port->flags & UPF_DEAD || uart_tx_stopped(port))
143 return;
144
145 port_dev = port->port_dev;
146
147 /* Increment the runtime PM usage count for the active check below */
148 err = pm_runtime_get(&port_dev->dev);
149 if (err < 0 && err != -EINPROGRESS) {
150 pm_runtime_put_noidle(&port_dev->dev);
151 return;
152 }
153
154 /*
155 * Start TX if enabled, and kick runtime PM. If the device is not
156 * enabled, serial_port_runtime_resume() calls start_tx() again
157 * after enabling the device.
158 */
159 if (!pm_runtime_enabled(port->dev) || pm_runtime_active(&port_dev->dev))
160 port->ops->start_tx(port);
161 pm_runtime_mark_last_busy(&port_dev->dev);
162 pm_runtime_put_autosuspend(&port_dev->dev);
163}
164
165static void uart_start(struct tty_struct *tty)
166{
167 struct uart_state *state = tty->driver_data;
168 struct uart_port *port;
169 unsigned long flags;
170
171 port = uart_port_lock(state, flags);
172 __uart_start(state);
173 uart_port_unlock(port, flags);
174}
175
176static void
177uart_update_mctrl(struct uart_port *port, unsigned int set, unsigned int clear)
178{
179 unsigned long flags;
180 unsigned int old;
181
182 uart_port_lock_irqsave(port, &flags);
183 old = port->mctrl;
184 port->mctrl = (old & ~clear) | set;
185 if (old != port->mctrl && !(port->rs485.flags & SER_RS485_ENABLED))
186 port->ops->set_mctrl(port, port->mctrl);
187 uart_port_unlock_irqrestore(port, flags);
188}
189
190#define uart_set_mctrl(port, set) uart_update_mctrl(port, set, 0)
191#define uart_clear_mctrl(port, clear) uart_update_mctrl(port, 0, clear)
192
193static void uart_port_dtr_rts(struct uart_port *uport, bool active)
194{
195 if (active)
196 uart_set_mctrl(uport, TIOCM_DTR | TIOCM_RTS);
197 else
198 uart_clear_mctrl(uport, TIOCM_DTR | TIOCM_RTS);
199}
200
201/* Caller holds port mutex */
202static void uart_change_line_settings(struct tty_struct *tty, struct uart_state *state,
203 const struct ktermios *old_termios)
204{
205 struct uart_port *uport = uart_port_check(state);
206 struct ktermios *termios;
207 bool old_hw_stopped;
208
209 /*
210 * If we have no tty, termios, or the port does not exist,
211 * then we can't set the parameters for this port.
212 */
213 if (!tty || uport->type == PORT_UNKNOWN)
214 return;
215
216 termios = &tty->termios;
217 uport->ops->set_termios(uport, termios, old_termios);
218
219 /*
220 * Set modem status enables based on termios cflag
221 */
222 uart_port_lock_irq(uport);
223 if (termios->c_cflag & CRTSCTS)
224 uport->status |= UPSTAT_CTS_ENABLE;
225 else
226 uport->status &= ~UPSTAT_CTS_ENABLE;
227
228 if (termios->c_cflag & CLOCAL)
229 uport->status &= ~UPSTAT_DCD_ENABLE;
230 else
231 uport->status |= UPSTAT_DCD_ENABLE;
232
233 /* reset sw-assisted CTS flow control based on (possibly) new mode */
234 old_hw_stopped = uport->hw_stopped;
235 uport->hw_stopped = uart_softcts_mode(uport) &&
236 !(uport->ops->get_mctrl(uport) & TIOCM_CTS);
237 if (uport->hw_stopped != old_hw_stopped) {
238 if (!old_hw_stopped)
239 uport->ops->stop_tx(uport);
240 else
241 __uart_start(state);
242 }
243 uart_port_unlock_irq(uport);
244}
245
246static int uart_alloc_xmit_buf(struct tty_port *port)
247{
248 struct uart_state *state = container_of(port, struct uart_state, port);
249 struct uart_port *uport;
250 unsigned long flags;
251 unsigned long page;
252
253 /*
254 * Initialise and allocate the transmit and temporary
255 * buffer.
256 */
257 page = get_zeroed_page(GFP_KERNEL);
258 if (!page)
259 return -ENOMEM;
260
261 uport = uart_port_lock(state, flags);
262 if (!state->port.xmit_buf) {
263 state->port.xmit_buf = (unsigned char *)page;
264 kfifo_init(&state->port.xmit_fifo, state->port.xmit_buf,
265 PAGE_SIZE);
266 uart_port_unlock(uport, flags);
267 } else {
268 uart_port_unlock(uport, flags);
269 /*
270 * Do not free() the page under the port lock, see
271 * uart_free_xmit_buf().
272 */
273 free_page(page);
274 }
275
276 return 0;
277}
278
279static void uart_free_xmit_buf(struct tty_port *port)
280{
281 struct uart_state *state = container_of(port, struct uart_state, port);
282 struct uart_port *uport;
283 unsigned long flags;
284 char *xmit_buf;
285
286 /*
287 * Do not free() the transmit buffer page under the port lock since
288 * this can create various circular locking scenarios. For instance,
289 * console driver may need to allocate/free a debug object, which
290 * can end up in printk() recursion.
291 */
292 uport = uart_port_lock(state, flags);
293 xmit_buf = port->xmit_buf;
294 port->xmit_buf = NULL;
295 INIT_KFIFO(port->xmit_fifo);
296 uart_port_unlock(uport, flags);
297
298 free_page((unsigned long)xmit_buf);
299}
300
301/*
302 * Startup the port. This will be called once per open. All calls
303 * will be serialised by the per-port mutex.
304 */
305static int uart_port_startup(struct tty_struct *tty, struct uart_state *state,
306 bool init_hw)
307{
308 struct uart_port *uport = uart_port_check(state);
309 int retval;
310
311 if (uport->type == PORT_UNKNOWN)
312 return 1;
313
314 /*
315 * Make sure the device is in D0 state.
316 */
317 uart_change_pm(state, UART_PM_STATE_ON);
318
319 retval = uart_alloc_xmit_buf(&state->port);
320 if (retval)
321 return retval;
322
323 retval = uport->ops->startup(uport);
324 if (retval == 0) {
325 if (uart_console(uport) && uport->cons->cflag) {
326 tty->termios.c_cflag = uport->cons->cflag;
327 tty->termios.c_ispeed = uport->cons->ispeed;
328 tty->termios.c_ospeed = uport->cons->ospeed;
329 uport->cons->cflag = 0;
330 uport->cons->ispeed = 0;
331 uport->cons->ospeed = 0;
332 }
333 /*
334 * Initialise the hardware port settings.
335 */
336 uart_change_line_settings(tty, state, NULL);
337
338 /*
339 * Setup the RTS and DTR signals once the
340 * port is open and ready to respond.
341 */
342 if (init_hw && C_BAUD(tty))
343 uart_port_dtr_rts(uport, true);
344 }
345
346 /*
347 * This is to allow setserial on this port. People may want to set
348 * port/irq/type and then reconfigure the port properly if it failed
349 * now.
350 */
351 if (retval && capable(CAP_SYS_ADMIN))
352 return 1;
353
354 return retval;
355}
356
357static int uart_startup(struct tty_struct *tty, struct uart_state *state,
358 bool init_hw)
359{
360 struct tty_port *port = &state->port;
361 struct uart_port *uport;
362 int retval;
363
364 if (tty_port_initialized(port))
365 goto out_base_port_startup;
366
367 retval = uart_port_startup(tty, state, init_hw);
368 if (retval) {
369 set_bit(TTY_IO_ERROR, &tty->flags);
370 return retval;
371 }
372
373out_base_port_startup:
374 uport = uart_port_check(state);
375 if (!uport)
376 return -EIO;
377
378 serial_base_port_startup(uport);
379
380 return 0;
381}
382
383/*
384 * This routine will shutdown a serial port; interrupts are disabled, and
385 * DTR is dropped if the hangup on close termio flag is on. Calls to
386 * uart_shutdown are serialised by the per-port semaphore.
387 *
388 * uport == NULL if uart_port has already been removed
389 */
390static void uart_shutdown(struct tty_struct *tty, struct uart_state *state)
391{
392 struct uart_port *uport = uart_port_check(state);
393 struct tty_port *port = &state->port;
394
395 /*
396 * Set the TTY IO error marker
397 */
398 if (tty)
399 set_bit(TTY_IO_ERROR, &tty->flags);
400
401 if (uport)
402 serial_base_port_shutdown(uport);
403
404 if (tty_port_initialized(port)) {
405 tty_port_set_initialized(port, false);
406
407 /*
408 * Turn off DTR and RTS early.
409 */
410 if (uport) {
411 if (uart_console(uport) && tty) {
412 uport->cons->cflag = tty->termios.c_cflag;
413 uport->cons->ispeed = tty->termios.c_ispeed;
414 uport->cons->ospeed = tty->termios.c_ospeed;
415 }
416
417 if (!tty || C_HUPCL(tty))
418 uart_port_dtr_rts(uport, false);
419 }
420
421 uart_port_shutdown(port);
422 }
423
424 /*
425 * It's possible for shutdown to be called after suspend if we get
426 * a DCD drop (hangup) at just the right time. Clear suspended bit so
427 * we don't try to resume a port that has been shutdown.
428 */
429 tty_port_set_suspended(port, false);
430
431 uart_free_xmit_buf(port);
432}
433
434/**
435 * uart_update_timeout - update per-port frame timing information
436 * @port: uart_port structure describing the port
437 * @cflag: termios cflag value
438 * @baud: speed of the port
439 *
440 * Set the @port frame timing information from which the FIFO timeout value is
441 * derived. The @cflag value should reflect the actual hardware settings as
442 * number of bits, parity, stop bits and baud rate is taken into account here.
443 *
444 * Locking: caller is expected to take @port->lock
445 */
446void
447uart_update_timeout(struct uart_port *port, unsigned int cflag,
448 unsigned int baud)
449{
450 u64 temp = tty_get_frame_size(cflag);
451
452 temp *= NSEC_PER_SEC;
453 port->frame_time = (unsigned int)DIV64_U64_ROUND_UP(temp, baud);
454}
455EXPORT_SYMBOL(uart_update_timeout);
456
457/**
458 * uart_get_baud_rate - return baud rate for a particular port
459 * @port: uart_port structure describing the port in question.
460 * @termios: desired termios settings
461 * @old: old termios (or %NULL)
462 * @min: minimum acceptable baud rate
463 * @max: maximum acceptable baud rate
464 *
465 * Decode the termios structure into a numeric baud rate, taking account of the
466 * magic 38400 baud rate (with spd_* flags), and mapping the %B0 rate to 9600
467 * baud.
468 *
469 * If the new baud rate is invalid, try the @old termios setting. If it's still
470 * invalid, we try 9600 baud. If that is also invalid 0 is returned.
471 *
472 * The @termios structure is updated to reflect the baud rate we're actually
473 * going to be using. Don't do this for the case where B0 is requested ("hang
474 * up").
475 *
476 * Locking: caller dependent
477 */
478unsigned int
479uart_get_baud_rate(struct uart_port *port, struct ktermios *termios,
480 const struct ktermios *old, unsigned int min, unsigned int max)
481{
482 unsigned int try;
483 unsigned int baud;
484 unsigned int altbaud;
485 int hung_up = 0;
486 upf_t flags = port->flags & UPF_SPD_MASK;
487
488 switch (flags) {
489 case UPF_SPD_HI:
490 altbaud = 57600;
491 break;
492 case UPF_SPD_VHI:
493 altbaud = 115200;
494 break;
495 case UPF_SPD_SHI:
496 altbaud = 230400;
497 break;
498 case UPF_SPD_WARP:
499 altbaud = 460800;
500 break;
501 default:
502 altbaud = 38400;
503 break;
504 }
505
506 for (try = 0; try < 2; try++) {
507 baud = tty_termios_baud_rate(termios);
508
509 /*
510 * The spd_hi, spd_vhi, spd_shi, spd_warp kludge...
511 * Die! Die! Die!
512 */
513 if (try == 0 && baud == 38400)
514 baud = altbaud;
515
516 /*
517 * Special case: B0 rate.
518 */
519 if (baud == 0) {
520 hung_up = 1;
521 baud = 9600;
522 }
523
524 if (baud >= min && baud <= max)
525 return baud;
526
527 /*
528 * Oops, the quotient was zero. Try again with
529 * the old baud rate if possible.
530 */
531 termios->c_cflag &= ~CBAUD;
532 if (old) {
533 baud = tty_termios_baud_rate(old);
534 if (!hung_up)
535 tty_termios_encode_baud_rate(termios,
536 baud, baud);
537 old = NULL;
538 continue;
539 }
540
541 /*
542 * As a last resort, if the range cannot be met then clip to
543 * the nearest chip supported rate.
544 */
545 if (!hung_up) {
546 if (baud <= min)
547 tty_termios_encode_baud_rate(termios,
548 min + 1, min + 1);
549 else
550 tty_termios_encode_baud_rate(termios,
551 max - 1, max - 1);
552 }
553 }
554 return 0;
555}
556EXPORT_SYMBOL(uart_get_baud_rate);
557
558/**
559 * uart_get_divisor - return uart clock divisor
560 * @port: uart_port structure describing the port
561 * @baud: desired baud rate
562 *
563 * Calculate the divisor (baud_base / baud) for the specified @baud,
564 * appropriately rounded.
565 *
566 * If 38400 baud and custom divisor is selected, return the custom divisor
567 * instead.
568 *
569 * Locking: caller dependent
570 */
571unsigned int
572uart_get_divisor(struct uart_port *port, unsigned int baud)
573{
574 unsigned int quot;
575
576 /*
577 * Old custom speed handling.
578 */
579 if (baud == 38400 && (port->flags & UPF_SPD_MASK) == UPF_SPD_CUST)
580 quot = port->custom_divisor;
581 else
582 quot = DIV_ROUND_CLOSEST(port->uartclk, 16 * baud);
583
584 return quot;
585}
586EXPORT_SYMBOL(uart_get_divisor);
587
588static int uart_put_char(struct tty_struct *tty, u8 c)
589{
590 struct uart_state *state = tty->driver_data;
591 struct uart_port *port;
592 unsigned long flags;
593 int ret = 0;
594
595 port = uart_port_lock(state, flags);
596 if (!state->port.xmit_buf) {
597 uart_port_unlock(port, flags);
598 return 0;
599 }
600
601 if (port)
602 ret = kfifo_put(&state->port.xmit_fifo, c);
603 uart_port_unlock(port, flags);
604 return ret;
605}
606
607static void uart_flush_chars(struct tty_struct *tty)
608{
609 uart_start(tty);
610}
611
612static ssize_t uart_write(struct tty_struct *tty, const u8 *buf, size_t count)
613{
614 struct uart_state *state = tty->driver_data;
615 struct uart_port *port;
616 unsigned long flags;
617 int ret = 0;
618
619 /*
620 * This means you called this function _after_ the port was
621 * closed. No cookie for you.
622 */
623 if (WARN_ON(!state))
624 return -EL3HLT;
625
626 port = uart_port_lock(state, flags);
627 if (!state->port.xmit_buf) {
628 uart_port_unlock(port, flags);
629 return 0;
630 }
631
632 if (port)
633 ret = kfifo_in(&state->port.xmit_fifo, buf, count);
634
635 __uart_start(state);
636 uart_port_unlock(port, flags);
637 return ret;
638}
639
640static unsigned int uart_write_room(struct tty_struct *tty)
641{
642 struct uart_state *state = tty->driver_data;
643 struct uart_port *port;
644 unsigned long flags;
645 unsigned int ret;
646
647 port = uart_port_lock(state, flags);
648 ret = kfifo_avail(&state->port.xmit_fifo);
649 uart_port_unlock(port, flags);
650 return ret;
651}
652
653static unsigned int uart_chars_in_buffer(struct tty_struct *tty)
654{
655 struct uart_state *state = tty->driver_data;
656 struct uart_port *port;
657 unsigned long flags;
658 unsigned int ret;
659
660 port = uart_port_lock(state, flags);
661 ret = kfifo_len(&state->port.xmit_fifo);
662 uart_port_unlock(port, flags);
663 return ret;
664}
665
666static void uart_flush_buffer(struct tty_struct *tty)
667{
668 struct uart_state *state = tty->driver_data;
669 struct uart_port *port;
670 unsigned long flags;
671
672 /*
673 * This means you called this function _after_ the port was
674 * closed. No cookie for you.
675 */
676 if (WARN_ON(!state))
677 return;
678
679 pr_debug("uart_flush_buffer(%d) called\n", tty->index);
680
681 port = uart_port_lock(state, flags);
682 if (!port)
683 return;
684 kfifo_reset(&state->port.xmit_fifo);
685 if (port->ops->flush_buffer)
686 port->ops->flush_buffer(port);
687 uart_port_unlock(port, flags);
688 tty_port_tty_wakeup(&state->port);
689}
690
691/*
692 * This function performs low-level write of high-priority XON/XOFF
693 * character and accounting for it.
694 *
695 * Requires uart_port to implement .serial_out().
696 */
697void uart_xchar_out(struct uart_port *uport, int offset)
698{
699 serial_port_out(uport, offset, uport->x_char);
700 uport->icount.tx++;
701 uport->x_char = 0;
702}
703EXPORT_SYMBOL_GPL(uart_xchar_out);
704
705/*
706 * This function is used to send a high-priority XON/XOFF character to
707 * the device
708 */
709static void uart_send_xchar(struct tty_struct *tty, u8 ch)
710{
711 struct uart_state *state = tty->driver_data;
712 struct uart_port *port;
713 unsigned long flags;
714
715 port = uart_port_ref(state);
716 if (!port)
717 return;
718
719 if (port->ops->send_xchar)
720 port->ops->send_xchar(port, ch);
721 else {
722 uart_port_lock_irqsave(port, &flags);
723 port->x_char = ch;
724 if (ch)
725 port->ops->start_tx(port);
726 uart_port_unlock_irqrestore(port, flags);
727 }
728 uart_port_deref(port);
729}
730
731static void uart_throttle(struct tty_struct *tty)
732{
733 struct uart_state *state = tty->driver_data;
734 upstat_t mask = UPSTAT_SYNC_FIFO;
735 struct uart_port *port;
736
737 port = uart_port_ref(state);
738 if (!port)
739 return;
740
741 if (I_IXOFF(tty))
742 mask |= UPSTAT_AUTOXOFF;
743 if (C_CRTSCTS(tty))
744 mask |= UPSTAT_AUTORTS;
745
746 if (port->status & mask) {
747 port->ops->throttle(port);
748 mask &= ~port->status;
749 }
750
751 if (mask & UPSTAT_AUTORTS)
752 uart_clear_mctrl(port, TIOCM_RTS);
753
754 if (mask & UPSTAT_AUTOXOFF)
755 uart_send_xchar(tty, STOP_CHAR(tty));
756
757 uart_port_deref(port);
758}
759
760static void uart_unthrottle(struct tty_struct *tty)
761{
762 struct uart_state *state = tty->driver_data;
763 upstat_t mask = UPSTAT_SYNC_FIFO;
764 struct uart_port *port;
765
766 port = uart_port_ref(state);
767 if (!port)
768 return;
769
770 if (I_IXOFF(tty))
771 mask |= UPSTAT_AUTOXOFF;
772 if (C_CRTSCTS(tty))
773 mask |= UPSTAT_AUTORTS;
774
775 if (port->status & mask) {
776 port->ops->unthrottle(port);
777 mask &= ~port->status;
778 }
779
780 if (mask & UPSTAT_AUTORTS)
781 uart_set_mctrl(port, TIOCM_RTS);
782
783 if (mask & UPSTAT_AUTOXOFF)
784 uart_send_xchar(tty, START_CHAR(tty));
785
786 uart_port_deref(port);
787}
788
789static int uart_get_info(struct tty_port *port, struct serial_struct *retinfo)
790{
791 struct uart_state *state = container_of(port, struct uart_state, port);
792 struct uart_port *uport;
793 int ret = -ENODEV;
794
795 /* Initialize structure in case we error out later to prevent any stack info leakage. */
796 *retinfo = (struct serial_struct){};
797
798 /*
799 * Ensure the state we copy is consistent and no hardware changes
800 * occur as we go
801 */
802 mutex_lock(&port->mutex);
803 uport = uart_port_check(state);
804 if (!uport)
805 goto out;
806
807 retinfo->type = uport->type;
808 retinfo->line = uport->line;
809 retinfo->port = uport->iobase;
810 if (HIGH_BITS_OFFSET)
811 retinfo->port_high = (long) uport->iobase >> HIGH_BITS_OFFSET;
812 retinfo->irq = uport->irq;
813 retinfo->flags = (__force int)uport->flags;
814 retinfo->xmit_fifo_size = uport->fifosize;
815 retinfo->baud_base = uport->uartclk / 16;
816 retinfo->close_delay = jiffies_to_msecs(port->close_delay) / 10;
817 retinfo->closing_wait = port->closing_wait == ASYNC_CLOSING_WAIT_NONE ?
818 ASYNC_CLOSING_WAIT_NONE :
819 jiffies_to_msecs(port->closing_wait) / 10;
820 retinfo->custom_divisor = uport->custom_divisor;
821 retinfo->hub6 = uport->hub6;
822 retinfo->io_type = uport->iotype;
823 retinfo->iomem_reg_shift = uport->regshift;
824 retinfo->iomem_base = (void *)(unsigned long)uport->mapbase;
825
826 ret = 0;
827out:
828 mutex_unlock(&port->mutex);
829 return ret;
830}
831
832static int uart_get_info_user(struct tty_struct *tty,
833 struct serial_struct *ss)
834{
835 struct uart_state *state = tty->driver_data;
836 struct tty_port *port = &state->port;
837
838 return uart_get_info(port, ss) < 0 ? -EIO : 0;
839}
840
841static int uart_set_info(struct tty_struct *tty, struct tty_port *port,
842 struct uart_state *state,
843 struct serial_struct *new_info)
844{
845 struct uart_port *uport = uart_port_check(state);
846 unsigned long new_port;
847 unsigned int change_irq, change_port, closing_wait;
848 unsigned int old_custom_divisor, close_delay;
849 upf_t old_flags, new_flags;
850 int retval = 0;
851
852 if (!uport)
853 return -EIO;
854
855 new_port = new_info->port;
856 if (HIGH_BITS_OFFSET)
857 new_port += (unsigned long) new_info->port_high << HIGH_BITS_OFFSET;
858
859 new_info->irq = irq_canonicalize(new_info->irq);
860 close_delay = msecs_to_jiffies(new_info->close_delay * 10);
861 closing_wait = new_info->closing_wait == ASYNC_CLOSING_WAIT_NONE ?
862 ASYNC_CLOSING_WAIT_NONE :
863 msecs_to_jiffies(new_info->closing_wait * 10);
864
865
866 change_irq = !(uport->flags & UPF_FIXED_PORT)
867 && new_info->irq != uport->irq;
868
869 /*
870 * Since changing the 'type' of the port changes its resource
871 * allocations, we should treat type changes the same as
872 * IO port changes.
873 */
874 change_port = !(uport->flags & UPF_FIXED_PORT)
875 && (new_port != uport->iobase ||
876 (unsigned long)new_info->iomem_base != uport->mapbase ||
877 new_info->hub6 != uport->hub6 ||
878 new_info->io_type != uport->iotype ||
879 new_info->iomem_reg_shift != uport->regshift ||
880 new_info->type != uport->type);
881
882 old_flags = uport->flags;
883 new_flags = (__force upf_t)new_info->flags;
884 old_custom_divisor = uport->custom_divisor;
885
886 if (!(uport->flags & UPF_FIXED_PORT)) {
887 unsigned int uartclk = new_info->baud_base * 16;
888 /* check needs to be done here before other settings made */
889 if (uartclk == 0) {
890 retval = -EINVAL;
891 goto exit;
892 }
893 }
894 if (!capable(CAP_SYS_ADMIN)) {
895 retval = -EPERM;
896 if (change_irq || change_port ||
897 (new_info->baud_base != uport->uartclk / 16) ||
898 (close_delay != port->close_delay) ||
899 (closing_wait != port->closing_wait) ||
900 (new_info->xmit_fifo_size &&
901 new_info->xmit_fifo_size != uport->fifosize) ||
902 (((new_flags ^ old_flags) & ~UPF_USR_MASK) != 0))
903 goto exit;
904 uport->flags = ((uport->flags & ~UPF_USR_MASK) |
905 (new_flags & UPF_USR_MASK));
906 uport->custom_divisor = new_info->custom_divisor;
907 goto check_and_exit;
908 }
909
910 if (change_irq || change_port) {
911 retval = security_locked_down(LOCKDOWN_TIOCSSERIAL);
912 if (retval)
913 goto exit;
914 }
915
916 /*
917 * Ask the low level driver to verify the settings.
918 */
919 if (uport->ops->verify_port)
920 retval = uport->ops->verify_port(uport, new_info);
921
922 if ((new_info->irq >= irq_get_nr_irqs()) || (new_info->irq < 0) ||
923 (new_info->baud_base < 9600))
924 retval = -EINVAL;
925
926 if (retval)
927 goto exit;
928
929 if (change_port || change_irq) {
930 retval = -EBUSY;
931
932 /*
933 * Make sure that we are the sole user of this port.
934 */
935 if (tty_port_users(port) > 1)
936 goto exit;
937
938 /*
939 * We need to shutdown the serial port at the old
940 * port/type/irq combination.
941 */
942 uart_shutdown(tty, state);
943 }
944
945 if (change_port) {
946 unsigned long old_iobase, old_mapbase;
947 unsigned int old_type, old_iotype, old_hub6, old_shift;
948
949 old_iobase = uport->iobase;
950 old_mapbase = uport->mapbase;
951 old_type = uport->type;
952 old_hub6 = uport->hub6;
953 old_iotype = uport->iotype;
954 old_shift = uport->regshift;
955
956 /*
957 * Free and release old regions
958 */
959 if (old_type != PORT_UNKNOWN && uport->ops->release_port)
960 uport->ops->release_port(uport);
961
962 uport->iobase = new_port;
963 uport->type = new_info->type;
964 uport->hub6 = new_info->hub6;
965 uport->iotype = new_info->io_type;
966 uport->regshift = new_info->iomem_reg_shift;
967 uport->mapbase = (unsigned long)new_info->iomem_base;
968
969 /*
970 * Claim and map the new regions
971 */
972 if (uport->type != PORT_UNKNOWN && uport->ops->request_port) {
973 retval = uport->ops->request_port(uport);
974 } else {
975 /* Always success - Jean II */
976 retval = 0;
977 }
978
979 /*
980 * If we fail to request resources for the
981 * new port, try to restore the old settings.
982 */
983 if (retval) {
984 uport->iobase = old_iobase;
985 uport->type = old_type;
986 uport->hub6 = old_hub6;
987 uport->iotype = old_iotype;
988 uport->regshift = old_shift;
989 uport->mapbase = old_mapbase;
990
991 if (old_type != PORT_UNKNOWN) {
992 retval = uport->ops->request_port(uport);
993 /*
994 * If we failed to restore the old settings,
995 * we fail like this.
996 */
997 if (retval)
998 uport->type = PORT_UNKNOWN;
999
1000 /*
1001 * We failed anyway.
1002 */
1003 retval = -EBUSY;
1004 }
1005
1006 /* Added to return the correct error -Ram Gupta */
1007 goto exit;
1008 }
1009 }
1010
1011 if (change_irq)
1012 uport->irq = new_info->irq;
1013 if (!(uport->flags & UPF_FIXED_PORT))
1014 uport->uartclk = new_info->baud_base * 16;
1015 uport->flags = (uport->flags & ~UPF_CHANGE_MASK) |
1016 (new_flags & UPF_CHANGE_MASK);
1017 uport->custom_divisor = new_info->custom_divisor;
1018 port->close_delay = close_delay;
1019 port->closing_wait = closing_wait;
1020 if (new_info->xmit_fifo_size)
1021 uport->fifosize = new_info->xmit_fifo_size;
1022
1023 check_and_exit:
1024 retval = 0;
1025 if (uport->type == PORT_UNKNOWN)
1026 goto exit;
1027 if (tty_port_initialized(port)) {
1028 if (((old_flags ^ uport->flags) & UPF_SPD_MASK) ||
1029 old_custom_divisor != uport->custom_divisor) {
1030 /*
1031 * If they're setting up a custom divisor or speed,
1032 * instead of clearing it, then bitch about it.
1033 */
1034 if (uport->flags & UPF_SPD_MASK) {
1035 dev_notice_ratelimited(uport->dev,
1036 "%s sets custom speed on %s. This is deprecated.\n",
1037 current->comm,
1038 tty_name(port->tty));
1039 }
1040 uart_change_line_settings(tty, state, NULL);
1041 }
1042 } else {
1043 retval = uart_startup(tty, state, true);
1044 if (retval == 0)
1045 tty_port_set_initialized(port, true);
1046 if (retval > 0)
1047 retval = 0;
1048 }
1049 exit:
1050 return retval;
1051}
1052
1053static int uart_set_info_user(struct tty_struct *tty, struct serial_struct *ss)
1054{
1055 struct uart_state *state = tty->driver_data;
1056 struct tty_port *port = &state->port;
1057 int retval;
1058
1059 down_write(&tty->termios_rwsem);
1060 /*
1061 * This semaphore protects port->count. It is also
1062 * very useful to prevent opens. Also, take the
1063 * port configuration semaphore to make sure that a
1064 * module insertion/removal doesn't change anything
1065 * under us.
1066 */
1067 mutex_lock(&port->mutex);
1068 retval = uart_set_info(tty, port, state, ss);
1069 mutex_unlock(&port->mutex);
1070 up_write(&tty->termios_rwsem);
1071 return retval;
1072}
1073
1074/**
1075 * uart_get_lsr_info - get line status register info
1076 * @tty: tty associated with the UART
1077 * @state: UART being queried
1078 * @value: returned modem value
1079 */
1080static int uart_get_lsr_info(struct tty_struct *tty,
1081 struct uart_state *state, unsigned int __user *value)
1082{
1083 struct uart_port *uport = uart_port_check(state);
1084 unsigned int result;
1085
1086 result = uport->ops->tx_empty(uport);
1087
1088 /*
1089 * If we're about to load something into the transmit
1090 * register, we'll pretend the transmitter isn't empty to
1091 * avoid a race condition (depending on when the transmit
1092 * interrupt happens).
1093 */
1094 if (uport->x_char ||
1095 (!kfifo_is_empty(&state->port.xmit_fifo) &&
1096 !uart_tx_stopped(uport)))
1097 result &= ~TIOCSER_TEMT;
1098
1099 return put_user(result, value);
1100}
1101
1102static int uart_tiocmget(struct tty_struct *tty)
1103{
1104 struct uart_state *state = tty->driver_data;
1105 struct tty_port *port = &state->port;
1106 struct uart_port *uport;
1107 int result;
1108
1109 guard(mutex)(&port->mutex);
1110
1111 uport = uart_port_check(state);
1112 if (!uport || tty_io_error(tty))
1113 return -EIO;
1114
1115 uart_port_lock_irq(uport);
1116 result = uport->mctrl;
1117 result |= uport->ops->get_mctrl(uport);
1118 uart_port_unlock_irq(uport);
1119
1120 return result;
1121}
1122
1123static int
1124uart_tiocmset(struct tty_struct *tty, unsigned int set, unsigned int clear)
1125{
1126 struct uart_state *state = tty->driver_data;
1127 struct tty_port *port = &state->port;
1128 struct uart_port *uport;
1129
1130 guard(mutex)(&port->mutex);
1131
1132 uport = uart_port_check(state);
1133 if (!uport || tty_io_error(tty))
1134 return -EIO;
1135
1136 uart_update_mctrl(uport, set, clear);
1137
1138 return 0;
1139}
1140
1141static int uart_break_ctl(struct tty_struct *tty, int break_state)
1142{
1143 struct uart_state *state = tty->driver_data;
1144 struct tty_port *port = &state->port;
1145 struct uart_port *uport;
1146
1147 guard(mutex)(&port->mutex);
1148
1149 uport = uart_port_check(state);
1150 if (!uport)
1151 return -EIO;
1152
1153 if (uport->type != PORT_UNKNOWN && uport->ops->break_ctl)
1154 uport->ops->break_ctl(uport, break_state);
1155
1156 return 0;
1157}
1158
1159static int uart_do_autoconfig(struct tty_struct *tty, struct uart_state *state)
1160{
1161 struct tty_port *port = &state->port;
1162 struct uart_port *uport;
1163 int flags, ret;
1164
1165 if (!capable(CAP_SYS_ADMIN))
1166 return -EPERM;
1167
1168 /*
1169 * Take the per-port semaphore. This prevents count from
1170 * changing, and hence any extra opens of the port while
1171 * we're auto-configuring.
1172 */
1173 scoped_cond_guard(mutex_intr, return -ERESTARTSYS, &port->mutex) {
1174 uport = uart_port_check(state);
1175 if (!uport)
1176 return -EIO;
1177
1178 if (tty_port_users(port) != 1)
1179 return -EBUSY;
1180
1181 uart_shutdown(tty, state);
1182
1183 /*
1184 * If we already have a port type configured,
1185 * we must release its resources.
1186 */
1187 if (uport->type != PORT_UNKNOWN && uport->ops->release_port)
1188 uport->ops->release_port(uport);
1189
1190 flags = UART_CONFIG_TYPE;
1191 if (uport->flags & UPF_AUTO_IRQ)
1192 flags |= UART_CONFIG_IRQ;
1193
1194 /*
1195 * This will claim the ports resources if
1196 * a port is found.
1197 */
1198 uport->ops->config_port(uport, flags);
1199
1200 ret = uart_startup(tty, state, true);
1201 if (ret < 0)
1202 return ret;
1203 if (ret > 0)
1204 return 0;
1205
1206 tty_port_set_initialized(port, true);
1207 }
1208
1209 return 0;
1210}
1211
1212static void uart_enable_ms(struct uart_port *uport)
1213{
1214 /*
1215 * Force modem status interrupts on
1216 */
1217 if (uport->ops->enable_ms)
1218 uport->ops->enable_ms(uport);
1219}
1220
1221/*
1222 * Wait for any of the 4 modem inputs (DCD,RI,DSR,CTS) to change
1223 * - mask passed in arg for lines of interest
1224 * (use |'ed TIOCM_RNG/DSR/CD/CTS for masking)
1225 * Caller should use TIOCGICOUNT to see which one it was
1226 *
1227 * FIXME: This wants extracting into a common all driver implementation
1228 * of TIOCMWAIT using tty_port.
1229 */
1230static int uart_wait_modem_status(struct uart_state *state, unsigned long arg)
1231{
1232 struct uart_port *uport;
1233 struct tty_port *port = &state->port;
1234 DECLARE_WAITQUEUE(wait, current);
1235 struct uart_icount cprev, cnow;
1236 int ret;
1237
1238 /*
1239 * note the counters on entry
1240 */
1241 uport = uart_port_ref(state);
1242 if (!uport)
1243 return -EIO;
1244 uart_port_lock_irq(uport);
1245 memcpy(&cprev, &uport->icount, sizeof(struct uart_icount));
1246 uart_enable_ms(uport);
1247 uart_port_unlock_irq(uport);
1248
1249 add_wait_queue(&port->delta_msr_wait, &wait);
1250 for (;;) {
1251 uart_port_lock_irq(uport);
1252 memcpy(&cnow, &uport->icount, sizeof(struct uart_icount));
1253 uart_port_unlock_irq(uport);
1254
1255 set_current_state(TASK_INTERRUPTIBLE);
1256
1257 if (((arg & TIOCM_RNG) && (cnow.rng != cprev.rng)) ||
1258 ((arg & TIOCM_DSR) && (cnow.dsr != cprev.dsr)) ||
1259 ((arg & TIOCM_CD) && (cnow.dcd != cprev.dcd)) ||
1260 ((arg & TIOCM_CTS) && (cnow.cts != cprev.cts))) {
1261 ret = 0;
1262 break;
1263 }
1264
1265 schedule();
1266
1267 /* see if a signal did it */
1268 if (signal_pending(current)) {
1269 ret = -ERESTARTSYS;
1270 break;
1271 }
1272
1273 cprev = cnow;
1274 }
1275 __set_current_state(TASK_RUNNING);
1276 remove_wait_queue(&port->delta_msr_wait, &wait);
1277 uart_port_deref(uport);
1278
1279 return ret;
1280}
1281
1282/*
1283 * Get counter of input serial line interrupts (DCD,RI,DSR,CTS)
1284 * Return: write counters to the user passed counter struct
1285 * NB: both 1->0 and 0->1 transitions are counted except for
1286 * RI where only 0->1 is counted.
1287 */
1288static int uart_get_icount(struct tty_struct *tty,
1289 struct serial_icounter_struct *icount)
1290{
1291 struct uart_state *state = tty->driver_data;
1292 struct uart_icount cnow;
1293 struct uart_port *uport;
1294
1295 uport = uart_port_ref(state);
1296 if (!uport)
1297 return -EIO;
1298 uart_port_lock_irq(uport);
1299 memcpy(&cnow, &uport->icount, sizeof(struct uart_icount));
1300 uart_port_unlock_irq(uport);
1301 uart_port_deref(uport);
1302
1303 icount->cts = cnow.cts;
1304 icount->dsr = cnow.dsr;
1305 icount->rng = cnow.rng;
1306 icount->dcd = cnow.dcd;
1307 icount->rx = cnow.rx;
1308 icount->tx = cnow.tx;
1309 icount->frame = cnow.frame;
1310 icount->overrun = cnow.overrun;
1311 icount->parity = cnow.parity;
1312 icount->brk = cnow.brk;
1313 icount->buf_overrun = cnow.buf_overrun;
1314
1315 return 0;
1316}
1317
1318#define SER_RS485_LEGACY_FLAGS (SER_RS485_ENABLED | SER_RS485_RTS_ON_SEND | \
1319 SER_RS485_RTS_AFTER_SEND | SER_RS485_RX_DURING_TX | \
1320 SER_RS485_TERMINATE_BUS)
1321
1322static int uart_check_rs485_flags(struct uart_port *port, struct serial_rs485 *rs485)
1323{
1324 u32 flags = rs485->flags;
1325
1326 /* Don't return -EINVAL for unsupported legacy flags */
1327 flags &= ~SER_RS485_LEGACY_FLAGS;
1328
1329 /*
1330 * For any bit outside of the legacy ones that is not supported by
1331 * the driver, return -EINVAL.
1332 */
1333 if (flags & ~port->rs485_supported.flags)
1334 return -EINVAL;
1335
1336 /* Asking for address w/o addressing mode? */
1337 if (!(rs485->flags & SER_RS485_ADDRB) &&
1338 (rs485->flags & (SER_RS485_ADDR_RECV|SER_RS485_ADDR_DEST)))
1339 return -EINVAL;
1340
1341 /* Address given but not enabled? */
1342 if (!(rs485->flags & SER_RS485_ADDR_RECV) && rs485->addr_recv)
1343 return -EINVAL;
1344 if (!(rs485->flags & SER_RS485_ADDR_DEST) && rs485->addr_dest)
1345 return -EINVAL;
1346
1347 return 0;
1348}
1349
1350static void uart_sanitize_serial_rs485_delays(struct uart_port *port,
1351 struct serial_rs485 *rs485)
1352{
1353 if (!port->rs485_supported.delay_rts_before_send) {
1354 if (rs485->delay_rts_before_send) {
1355 dev_warn_ratelimited(port->dev,
1356 "%s (%d): RTS delay before sending not supported\n",
1357 port->name, port->line);
1358 }
1359 rs485->delay_rts_before_send = 0;
1360 } else if (rs485->delay_rts_before_send > RS485_MAX_RTS_DELAY) {
1361 rs485->delay_rts_before_send = RS485_MAX_RTS_DELAY;
1362 dev_warn_ratelimited(port->dev,
1363 "%s (%d): RTS delay before sending clamped to %u ms\n",
1364 port->name, port->line, rs485->delay_rts_before_send);
1365 }
1366
1367 if (!port->rs485_supported.delay_rts_after_send) {
1368 if (rs485->delay_rts_after_send) {
1369 dev_warn_ratelimited(port->dev,
1370 "%s (%d): RTS delay after sending not supported\n",
1371 port->name, port->line);
1372 }
1373 rs485->delay_rts_after_send = 0;
1374 } else if (rs485->delay_rts_after_send > RS485_MAX_RTS_DELAY) {
1375 rs485->delay_rts_after_send = RS485_MAX_RTS_DELAY;
1376 dev_warn_ratelimited(port->dev,
1377 "%s (%d): RTS delay after sending clamped to %u ms\n",
1378 port->name, port->line, rs485->delay_rts_after_send);
1379 }
1380}
1381
1382static void uart_sanitize_serial_rs485(struct uart_port *port, struct serial_rs485 *rs485)
1383{
1384 u32 supported_flags = port->rs485_supported.flags;
1385
1386 if (!(rs485->flags & SER_RS485_ENABLED)) {
1387 memset(rs485, 0, sizeof(*rs485));
1388 return;
1389 }
1390
1391 /* Clear other RS485 flags but SER_RS485_TERMINATE_BUS and return if enabling RS422 */
1392 if (rs485->flags & SER_RS485_MODE_RS422) {
1393 rs485->flags &= (SER_RS485_ENABLED | SER_RS485_MODE_RS422 | SER_RS485_TERMINATE_BUS);
1394 return;
1395 }
1396
1397 rs485->flags &= supported_flags;
1398
1399 /* Pick sane settings if the user hasn't */
1400 if (!(rs485->flags & SER_RS485_RTS_ON_SEND) ==
1401 !(rs485->flags & SER_RS485_RTS_AFTER_SEND)) {
1402 if (supported_flags & SER_RS485_RTS_ON_SEND) {
1403 rs485->flags |= SER_RS485_RTS_ON_SEND;
1404 rs485->flags &= ~SER_RS485_RTS_AFTER_SEND;
1405
1406 dev_warn_ratelimited(port->dev,
1407 "%s (%d): invalid RTS setting, using RTS_ON_SEND instead\n",
1408 port->name, port->line);
1409 } else {
1410 rs485->flags |= SER_RS485_RTS_AFTER_SEND;
1411 rs485->flags &= ~SER_RS485_RTS_ON_SEND;
1412
1413 dev_warn_ratelimited(port->dev,
1414 "%s (%d): invalid RTS setting, using RTS_AFTER_SEND instead\n",
1415 port->name, port->line);
1416 }
1417 }
1418
1419 uart_sanitize_serial_rs485_delays(port, rs485);
1420
1421 /* Return clean padding area to userspace */
1422 memset(rs485->padding0, 0, sizeof(rs485->padding0));
1423 memset(rs485->padding1, 0, sizeof(rs485->padding1));
1424}
1425
1426static void uart_set_rs485_termination(struct uart_port *port,
1427 const struct serial_rs485 *rs485)
1428{
1429 if (!(rs485->flags & SER_RS485_ENABLED))
1430 return;
1431
1432 gpiod_set_value_cansleep(port->rs485_term_gpio,
1433 !!(rs485->flags & SER_RS485_TERMINATE_BUS));
1434}
1435
1436static void uart_set_rs485_rx_during_tx(struct uart_port *port,
1437 const struct serial_rs485 *rs485)
1438{
1439 if (!(rs485->flags & SER_RS485_ENABLED))
1440 return;
1441
1442 gpiod_set_value_cansleep(port->rs485_rx_during_tx_gpio,
1443 !!(rs485->flags & SER_RS485_RX_DURING_TX));
1444}
1445
1446static int uart_rs485_config(struct uart_port *port)
1447{
1448 struct serial_rs485 *rs485 = &port->rs485;
1449 unsigned long flags;
1450 int ret;
1451
1452 if (!(rs485->flags & SER_RS485_ENABLED))
1453 return 0;
1454
1455 uart_sanitize_serial_rs485(port, rs485);
1456 uart_set_rs485_termination(port, rs485);
1457 uart_set_rs485_rx_during_tx(port, rs485);
1458
1459 uart_port_lock_irqsave(port, &flags);
1460 ret = port->rs485_config(port, NULL, rs485);
1461 uart_port_unlock_irqrestore(port, flags);
1462 if (ret) {
1463 memset(rs485, 0, sizeof(*rs485));
1464 /* unset GPIOs */
1465 gpiod_set_value_cansleep(port->rs485_term_gpio, 0);
1466 gpiod_set_value_cansleep(port->rs485_rx_during_tx_gpio, 0);
1467 }
1468
1469 return ret;
1470}
1471
1472static int uart_get_rs485_config(struct uart_port *port,
1473 struct serial_rs485 __user *rs485)
1474{
1475 unsigned long flags;
1476 struct serial_rs485 aux;
1477
1478 uart_port_lock_irqsave(port, &flags);
1479 aux = port->rs485;
1480 uart_port_unlock_irqrestore(port, flags);
1481
1482 if (copy_to_user(rs485, &aux, sizeof(aux)))
1483 return -EFAULT;
1484
1485 return 0;
1486}
1487
1488static int uart_set_rs485_config(struct tty_struct *tty, struct uart_port *port,
1489 struct serial_rs485 __user *rs485_user)
1490{
1491 struct serial_rs485 rs485;
1492 int ret;
1493 unsigned long flags;
1494
1495 if (!(port->rs485_supported.flags & SER_RS485_ENABLED))
1496 return -ENOTTY;
1497
1498 if (copy_from_user(&rs485, rs485_user, sizeof(*rs485_user)))
1499 return -EFAULT;
1500
1501 ret = uart_check_rs485_flags(port, &rs485);
1502 if (ret)
1503 return ret;
1504 uart_sanitize_serial_rs485(port, &rs485);
1505 uart_set_rs485_termination(port, &rs485);
1506 uart_set_rs485_rx_during_tx(port, &rs485);
1507
1508 uart_port_lock_irqsave(port, &flags);
1509 ret = port->rs485_config(port, &tty->termios, &rs485);
1510 if (!ret) {
1511 port->rs485 = rs485;
1512
1513 /* Reset RTS and other mctrl lines when disabling RS485 */
1514 if (!(rs485.flags & SER_RS485_ENABLED))
1515 port->ops->set_mctrl(port, port->mctrl);
1516 }
1517 uart_port_unlock_irqrestore(port, flags);
1518 if (ret) {
1519 /* restore old GPIO settings */
1520 gpiod_set_value_cansleep(port->rs485_term_gpio,
1521 !!(port->rs485.flags & SER_RS485_TERMINATE_BUS));
1522 gpiod_set_value_cansleep(port->rs485_rx_during_tx_gpio,
1523 !!(port->rs485.flags & SER_RS485_RX_DURING_TX));
1524 return ret;
1525 }
1526
1527 if (copy_to_user(rs485_user, &port->rs485, sizeof(port->rs485)))
1528 return -EFAULT;
1529
1530 return 0;
1531}
1532
1533static int uart_get_iso7816_config(struct uart_port *port,
1534 struct serial_iso7816 __user *iso7816)
1535{
1536 unsigned long flags;
1537 struct serial_iso7816 aux;
1538
1539 if (!port->iso7816_config)
1540 return -ENOTTY;
1541
1542 uart_port_lock_irqsave(port, &flags);
1543 aux = port->iso7816;
1544 uart_port_unlock_irqrestore(port, flags);
1545
1546 if (copy_to_user(iso7816, &aux, sizeof(aux)))
1547 return -EFAULT;
1548
1549 return 0;
1550}
1551
1552static int uart_set_iso7816_config(struct uart_port *port,
1553 struct serial_iso7816 __user *iso7816_user)
1554{
1555 struct serial_iso7816 iso7816;
1556 int i, ret;
1557 unsigned long flags;
1558
1559 if (!port->iso7816_config)
1560 return -ENOTTY;
1561
1562 if (copy_from_user(&iso7816, iso7816_user, sizeof(*iso7816_user)))
1563 return -EFAULT;
1564
1565 /*
1566 * There are 5 words reserved for future use. Check that userspace
1567 * doesn't put stuff in there to prevent breakages in the future.
1568 */
1569 for (i = 0; i < ARRAY_SIZE(iso7816.reserved); i++)
1570 if (iso7816.reserved[i])
1571 return -EINVAL;
1572
1573 uart_port_lock_irqsave(port, &flags);
1574 ret = port->iso7816_config(port, &iso7816);
1575 uart_port_unlock_irqrestore(port, flags);
1576 if (ret)
1577 return ret;
1578
1579 if (copy_to_user(iso7816_user, &port->iso7816, sizeof(port->iso7816)))
1580 return -EFAULT;
1581
1582 return 0;
1583}
1584
1585/*
1586 * Called via sys_ioctl. We can use spin_lock_irq() here.
1587 */
1588static int
1589uart_ioctl(struct tty_struct *tty, unsigned int cmd, unsigned long arg)
1590{
1591 struct uart_state *state = tty->driver_data;
1592 struct tty_port *port = &state->port;
1593 struct uart_port *uport;
1594 void __user *uarg = (void __user *)arg;
1595 int ret = -ENOIOCTLCMD;
1596
1597
1598 /*
1599 * These ioctls don't rely on the hardware to be present.
1600 */
1601 switch (cmd) {
1602 case TIOCSERCONFIG:
1603 down_write(&tty->termios_rwsem);
1604 ret = uart_do_autoconfig(tty, state);
1605 up_write(&tty->termios_rwsem);
1606 break;
1607 }
1608
1609 if (ret != -ENOIOCTLCMD)
1610 goto out;
1611
1612 if (tty_io_error(tty)) {
1613 ret = -EIO;
1614 goto out;
1615 }
1616
1617 /*
1618 * The following should only be used when hardware is present.
1619 */
1620 switch (cmd) {
1621 case TIOCMIWAIT:
1622 ret = uart_wait_modem_status(state, arg);
1623 break;
1624 }
1625
1626 if (ret != -ENOIOCTLCMD)
1627 goto out;
1628
1629 /* rs485_config requires more locking than others */
1630 if (cmd == TIOCSRS485)
1631 down_write(&tty->termios_rwsem);
1632
1633 mutex_lock(&port->mutex);
1634 uport = uart_port_check(state);
1635
1636 if (!uport || tty_io_error(tty)) {
1637 ret = -EIO;
1638 goto out_up;
1639 }
1640
1641 /*
1642 * All these rely on hardware being present and need to be
1643 * protected against the tty being hung up.
1644 */
1645
1646 switch (cmd) {
1647 case TIOCSERGETLSR: /* Get line status register */
1648 ret = uart_get_lsr_info(tty, state, uarg);
1649 break;
1650
1651 case TIOCGRS485:
1652 ret = uart_get_rs485_config(uport, uarg);
1653 break;
1654
1655 case TIOCSRS485:
1656 ret = uart_set_rs485_config(tty, uport, uarg);
1657 break;
1658
1659 case TIOCSISO7816:
1660 ret = uart_set_iso7816_config(state->uart_port, uarg);
1661 break;
1662
1663 case TIOCGISO7816:
1664 ret = uart_get_iso7816_config(state->uart_port, uarg);
1665 break;
1666 default:
1667 if (uport->ops->ioctl)
1668 ret = uport->ops->ioctl(uport, cmd, arg);
1669 break;
1670 }
1671out_up:
1672 mutex_unlock(&port->mutex);
1673 if (cmd == TIOCSRS485)
1674 up_write(&tty->termios_rwsem);
1675out:
1676 return ret;
1677}
1678
1679static void uart_set_ldisc(struct tty_struct *tty)
1680{
1681 struct uart_state *state = tty->driver_data;
1682 struct uart_port *uport;
1683 struct tty_port *port = &state->port;
1684
1685 if (!tty_port_initialized(port))
1686 return;
1687
1688 mutex_lock(&state->port.mutex);
1689 uport = uart_port_check(state);
1690 if (uport && uport->ops->set_ldisc)
1691 uport->ops->set_ldisc(uport, &tty->termios);
1692 mutex_unlock(&state->port.mutex);
1693}
1694
1695static void uart_set_termios(struct tty_struct *tty,
1696 const struct ktermios *old_termios)
1697{
1698 struct uart_state *state = tty->driver_data;
1699 struct uart_port *uport;
1700 unsigned int cflag = tty->termios.c_cflag;
1701 unsigned int iflag_mask = IGNBRK|BRKINT|IGNPAR|PARMRK|INPCK;
1702 bool sw_changed = false;
1703
1704 guard(mutex)(&state->port.mutex);
1705
1706 uport = uart_port_check(state);
1707 if (!uport)
1708 return;
1709
1710 /*
1711 * Drivers doing software flow control also need to know
1712 * about changes to these input settings.
1713 */
1714 if (uport->flags & UPF_SOFT_FLOW) {
1715 iflag_mask |= IXANY|IXON|IXOFF;
1716 sw_changed =
1717 tty->termios.c_cc[VSTART] != old_termios->c_cc[VSTART] ||
1718 tty->termios.c_cc[VSTOP] != old_termios->c_cc[VSTOP];
1719 }
1720
1721 /*
1722 * These are the bits that are used to setup various
1723 * flags in the low level driver. We can ignore the Bfoo
1724 * bits in c_cflag; c_[io]speed will always be set
1725 * appropriately by set_termios() in tty_ioctl.c
1726 */
1727 if ((cflag ^ old_termios->c_cflag) == 0 &&
1728 tty->termios.c_ospeed == old_termios->c_ospeed &&
1729 tty->termios.c_ispeed == old_termios->c_ispeed &&
1730 ((tty->termios.c_iflag ^ old_termios->c_iflag) & iflag_mask) == 0 &&
1731 !sw_changed)
1732 return;
1733
1734 uart_change_line_settings(tty, state, old_termios);
1735 /* reload cflag from termios; port driver may have overridden flags */
1736 cflag = tty->termios.c_cflag;
1737
1738 /* Handle transition to B0 status */
1739 if (((old_termios->c_cflag & CBAUD) != B0) && ((cflag & CBAUD) == B0))
1740 uart_clear_mctrl(uport, TIOCM_RTS | TIOCM_DTR);
1741 /* Handle transition away from B0 status */
1742 else if (((old_termios->c_cflag & CBAUD) == B0) && ((cflag & CBAUD) != B0)) {
1743 unsigned int mask = TIOCM_DTR;
1744
1745 if (!(cflag & CRTSCTS) || !tty_throttled(tty))
1746 mask |= TIOCM_RTS;
1747 uart_set_mctrl(uport, mask);
1748 }
1749}
1750
1751/*
1752 * Calls to uart_close() are serialised via the tty_lock in
1753 * drivers/tty/tty_io.c:tty_release()
1754 * drivers/tty/tty_io.c:do_tty_hangup()
1755 */
1756static void uart_close(struct tty_struct *tty, struct file *filp)
1757{
1758 struct uart_state *state = tty->driver_data;
1759
1760 if (!state) {
1761 struct uart_driver *drv = tty->driver->driver_state;
1762 struct tty_port *port;
1763
1764 state = drv->state + tty->index;
1765 port = &state->port;
1766 spin_lock_irq(&port->lock);
1767 --port->count;
1768 spin_unlock_irq(&port->lock);
1769 return;
1770 }
1771
1772 pr_debug("uart_close(%d) called\n", tty->index);
1773
1774 tty_port_close(tty->port, tty, filp);
1775}
1776
1777static void uart_tty_port_shutdown(struct tty_port *port)
1778{
1779 struct uart_state *state = container_of(port, struct uart_state, port);
1780 struct uart_port *uport = uart_port_check(state);
1781
1782 /*
1783 * At this point, we stop accepting input. To do this, we
1784 * disable the receive line status interrupts.
1785 */
1786 if (WARN(!uport, "detached port still initialized!\n"))
1787 return;
1788
1789 uart_port_lock_irq(uport);
1790 uport->ops->stop_rx(uport);
1791 uart_port_unlock_irq(uport);
1792
1793 serial_base_port_shutdown(uport);
1794 uart_port_shutdown(port);
1795
1796 /*
1797 * It's possible for shutdown to be called after suspend if we get
1798 * a DCD drop (hangup) at just the right time. Clear suspended bit so
1799 * we don't try to resume a port that has been shutdown.
1800 */
1801 tty_port_set_suspended(port, false);
1802
1803 uart_free_xmit_buf(port);
1804
1805 uart_change_pm(state, UART_PM_STATE_OFF);
1806}
1807
1808static void uart_wait_until_sent(struct tty_struct *tty, int timeout)
1809{
1810 struct uart_state *state = tty->driver_data;
1811 struct uart_port *port;
1812 unsigned long char_time, expire, fifo_timeout;
1813
1814 port = uart_port_ref(state);
1815 if (!port)
1816 return;
1817
1818 if (port->type == PORT_UNKNOWN || port->fifosize == 0) {
1819 uart_port_deref(port);
1820 return;
1821 }
1822
1823 /*
1824 * Set the check interval to be 1/5 of the estimated time to
1825 * send a single character, and make it at least 1. The check
1826 * interval should also be less than the timeout.
1827 *
1828 * Note: we have to use pretty tight timings here to satisfy
1829 * the NIST-PCTS.
1830 */
1831 char_time = max(nsecs_to_jiffies(port->frame_time / 5), 1UL);
1832
1833 if (timeout && timeout < char_time)
1834 char_time = timeout;
1835
1836 if (!uart_cts_enabled(port)) {
1837 /*
1838 * If the transmitter hasn't cleared in twice the approximate
1839 * amount of time to send the entire FIFO, it probably won't
1840 * ever clear. This assumes the UART isn't doing flow
1841 * control, which is currently the case. Hence, if it ever
1842 * takes longer than FIFO timeout, this is probably due to a
1843 * UART bug of some kind. So, we clamp the timeout parameter at
1844 * 2 * FIFO timeout.
1845 */
1846 fifo_timeout = uart_fifo_timeout(port);
1847 if (timeout == 0 || timeout > 2 * fifo_timeout)
1848 timeout = 2 * fifo_timeout;
1849 }
1850
1851 expire = jiffies + timeout;
1852
1853 pr_debug("uart_wait_until_sent(%d), jiffies=%lu, expire=%lu...\n",
1854 port->line, jiffies, expire);
1855
1856 /*
1857 * Check whether the transmitter is empty every 'char_time'.
1858 * 'timeout' / 'expire' give us the maximum amount of time
1859 * we wait.
1860 */
1861 while (!port->ops->tx_empty(port)) {
1862 msleep_interruptible(jiffies_to_msecs(char_time));
1863 if (signal_pending(current))
1864 break;
1865 if (timeout && time_after(jiffies, expire))
1866 break;
1867 }
1868 uart_port_deref(port);
1869}
1870
1871/*
1872 * Calls to uart_hangup() are serialised by the tty_lock in
1873 * drivers/tty/tty_io.c:do_tty_hangup()
1874 * This runs from a workqueue and can sleep for a _short_ time only.
1875 */
1876static void uart_hangup(struct tty_struct *tty)
1877{
1878 struct uart_state *state = tty->driver_data;
1879 struct tty_port *port = &state->port;
1880 struct uart_port *uport;
1881 unsigned long flags;
1882
1883 pr_debug("uart_hangup(%d)\n", tty->index);
1884
1885 mutex_lock(&port->mutex);
1886 uport = uart_port_check(state);
1887 WARN(!uport, "hangup of detached port!\n");
1888
1889 if (tty_port_active(port)) {
1890 uart_flush_buffer(tty);
1891 uart_shutdown(tty, state);
1892 spin_lock_irqsave(&port->lock, flags);
1893 port->count = 0;
1894 spin_unlock_irqrestore(&port->lock, flags);
1895 tty_port_set_active(port, false);
1896 tty_port_tty_set(port, NULL);
1897 if (uport && !uart_console(uport))
1898 uart_change_pm(state, UART_PM_STATE_OFF);
1899 wake_up_interruptible(&port->open_wait);
1900 wake_up_interruptible(&port->delta_msr_wait);
1901 }
1902 mutex_unlock(&port->mutex);
1903}
1904
1905/* uport == NULL if uart_port has already been removed */
1906static void uart_port_shutdown(struct tty_port *port)
1907{
1908 struct uart_state *state = container_of(port, struct uart_state, port);
1909 struct uart_port *uport = uart_port_check(state);
1910
1911 /*
1912 * clear delta_msr_wait queue to avoid mem leaks: we may free
1913 * the irq here so the queue might never be woken up. Note
1914 * that we won't end up waiting on delta_msr_wait again since
1915 * any outstanding file descriptors should be pointing at
1916 * hung_up_tty_fops now.
1917 */
1918 wake_up_interruptible(&port->delta_msr_wait);
1919
1920 if (uport) {
1921 /* Free the IRQ and disable the port. */
1922 uport->ops->shutdown(uport);
1923
1924 /* Ensure that the IRQ handler isn't running on another CPU. */
1925 synchronize_irq(uport->irq);
1926 }
1927}
1928
1929static bool uart_carrier_raised(struct tty_port *port)
1930{
1931 struct uart_state *state = container_of(port, struct uart_state, port);
1932 struct uart_port *uport;
1933 int mctrl;
1934
1935 uport = uart_port_ref(state);
1936 /*
1937 * Should never observe uport == NULL since checks for hangup should
1938 * abort the tty_port_block_til_ready() loop before checking for carrier
1939 * raised -- but report carrier raised if it does anyway so open will
1940 * continue and not sleep
1941 */
1942 if (WARN_ON(!uport))
1943 return true;
1944 uart_port_lock_irq(uport);
1945 uart_enable_ms(uport);
1946 mctrl = uport->ops->get_mctrl(uport);
1947 uart_port_unlock_irq(uport);
1948 uart_port_deref(uport);
1949
1950 return mctrl & TIOCM_CAR;
1951}
1952
1953static void uart_dtr_rts(struct tty_port *port, bool active)
1954{
1955 struct uart_state *state = container_of(port, struct uart_state, port);
1956 struct uart_port *uport;
1957
1958 uport = uart_port_ref(state);
1959 if (!uport)
1960 return;
1961 uart_port_dtr_rts(uport, active);
1962 uart_port_deref(uport);
1963}
1964
1965static int uart_install(struct tty_driver *driver, struct tty_struct *tty)
1966{
1967 struct uart_driver *drv = driver->driver_state;
1968 struct uart_state *state = drv->state + tty->index;
1969
1970 tty->driver_data = state;
1971
1972 return tty_standard_install(driver, tty);
1973}
1974
1975/*
1976 * Calls to uart_open are serialised by the tty_lock in
1977 * drivers/tty/tty_io.c:tty_open()
1978 * Note that if this fails, then uart_close() _will_ be called.
1979 *
1980 * In time, we want to scrap the "opening nonpresent ports"
1981 * behaviour and implement an alternative way for setserial
1982 * to set base addresses/ports/types. This will allow us to
1983 * get rid of a certain amount of extra tests.
1984 */
1985static int uart_open(struct tty_struct *tty, struct file *filp)
1986{
1987 struct uart_state *state = tty->driver_data;
1988 int retval;
1989
1990 retval = tty_port_open(&state->port, tty, filp);
1991 if (retval > 0)
1992 retval = 0;
1993
1994 return retval;
1995}
1996
1997static int uart_port_activate(struct tty_port *port, struct tty_struct *tty)
1998{
1999 struct uart_state *state = container_of(port, struct uart_state, port);
2000 struct uart_port *uport;
2001 int ret;
2002
2003 uport = uart_port_check(state);
2004 if (!uport || uport->flags & UPF_DEAD)
2005 return -ENXIO;
2006
2007 /*
2008 * Start up the serial port.
2009 */
2010 ret = uart_startup(tty, state, false);
2011 if (ret > 0)
2012 tty_port_set_active(port, true);
2013
2014 return ret;
2015}
2016
2017static const char *uart_type(struct uart_port *port)
2018{
2019 const char *str = NULL;
2020
2021 if (port->ops->type)
2022 str = port->ops->type(port);
2023
2024 if (!str)
2025 str = "unknown";
2026
2027 return str;
2028}
2029
2030#ifdef CONFIG_PROC_FS
2031
2032static void uart_line_info(struct seq_file *m, struct uart_driver *drv, int i)
2033{
2034 struct uart_state *state = drv->state + i;
2035 struct tty_port *port = &state->port;
2036 enum uart_pm_state pm_state;
2037 struct uart_port *uport;
2038 char stat_buf[32];
2039 unsigned int status;
2040 int mmio;
2041
2042 guard(mutex)(&port->mutex);
2043
2044 uport = uart_port_check(state);
2045 if (!uport)
2046 return;
2047
2048 mmio = uport->iotype >= UPIO_MEM;
2049 seq_printf(m, "%d: uart:%s %s%08llX irq:%d",
2050 uport->line, uart_type(uport),
2051 mmio ? "mmio:0x" : "port:",
2052 mmio ? (unsigned long long)uport->mapbase
2053 : (unsigned long long)uport->iobase,
2054 uport->irq);
2055
2056 if (uport->type == PORT_UNKNOWN) {
2057 seq_putc(m, '\n');
2058 return;
2059 }
2060
2061 if (capable(CAP_SYS_ADMIN)) {
2062 pm_state = state->pm_state;
2063 if (pm_state != UART_PM_STATE_ON)
2064 uart_change_pm(state, UART_PM_STATE_ON);
2065 uart_port_lock_irq(uport);
2066 status = uport->ops->get_mctrl(uport);
2067 uart_port_unlock_irq(uport);
2068 if (pm_state != UART_PM_STATE_ON)
2069 uart_change_pm(state, pm_state);
2070
2071 seq_printf(m, " tx:%d rx:%d",
2072 uport->icount.tx, uport->icount.rx);
2073 if (uport->icount.frame)
2074 seq_printf(m, " fe:%d", uport->icount.frame);
2075 if (uport->icount.parity)
2076 seq_printf(m, " pe:%d", uport->icount.parity);
2077 if (uport->icount.brk)
2078 seq_printf(m, " brk:%d", uport->icount.brk);
2079 if (uport->icount.overrun)
2080 seq_printf(m, " oe:%d", uport->icount.overrun);
2081 if (uport->icount.buf_overrun)
2082 seq_printf(m, " bo:%d", uport->icount.buf_overrun);
2083
2084#define INFOBIT(bit, str) \
2085 if (uport->mctrl & (bit)) \
2086 strncat(stat_buf, (str), sizeof(stat_buf) - \
2087 strlen(stat_buf) - 2)
2088#define STATBIT(bit, str) \
2089 if (status & (bit)) \
2090 strncat(stat_buf, (str), sizeof(stat_buf) - \
2091 strlen(stat_buf) - 2)
2092
2093 stat_buf[0] = '\0';
2094 stat_buf[1] = '\0';
2095 INFOBIT(TIOCM_RTS, "|RTS");
2096 STATBIT(TIOCM_CTS, "|CTS");
2097 INFOBIT(TIOCM_DTR, "|DTR");
2098 STATBIT(TIOCM_DSR, "|DSR");
2099 STATBIT(TIOCM_CAR, "|CD");
2100 STATBIT(TIOCM_RNG, "|RI");
2101 if (stat_buf[0])
2102 stat_buf[0] = ' ';
2103
2104 seq_puts(m, stat_buf);
2105 }
2106 seq_putc(m, '\n');
2107#undef STATBIT
2108#undef INFOBIT
2109}
2110
2111static int uart_proc_show(struct seq_file *m, void *v)
2112{
2113 struct tty_driver *ttydrv = m->private;
2114 struct uart_driver *drv = ttydrv->driver_state;
2115 int i;
2116
2117 seq_printf(m, "serinfo:1.0 driver%s%s revision:%s\n", "", "", "");
2118 for (i = 0; i < drv->nr; i++)
2119 uart_line_info(m, drv, i);
2120 return 0;
2121}
2122#endif
2123
2124static void uart_port_spin_lock_init(struct uart_port *port)
2125{
2126 spin_lock_init(&port->lock);
2127 lockdep_set_class(&port->lock, &port_lock_key);
2128}
2129
2130#if defined(CONFIG_SERIAL_CORE_CONSOLE) || defined(CONFIG_CONSOLE_POLL)
2131/**
2132 * uart_console_write - write a console message to a serial port
2133 * @port: the port to write the message
2134 * @s: array of characters
2135 * @count: number of characters in string to write
2136 * @putchar: function to write character to port
2137 */
2138void uart_console_write(struct uart_port *port, const char *s,
2139 unsigned int count,
2140 void (*putchar)(struct uart_port *, unsigned char))
2141{
2142 unsigned int i;
2143
2144 for (i = 0; i < count; i++, s++) {
2145 if (*s == '\n')
2146 putchar(port, '\r');
2147 putchar(port, *s);
2148 }
2149}
2150EXPORT_SYMBOL_GPL(uart_console_write);
2151
2152/**
2153 * uart_get_console - get uart port for console
2154 * @ports: ports to search in
2155 * @nr: number of @ports
2156 * @co: console to search for
2157 * Returns: uart_port for the console @co
2158 *
2159 * Check whether an invalid uart number has been specified (as @co->index), and
2160 * if so, search for the first available port that does have console support.
2161 */
2162struct uart_port * __init
2163uart_get_console(struct uart_port *ports, int nr, struct console *co)
2164{
2165 int idx = co->index;
2166
2167 if (idx < 0 || idx >= nr || (ports[idx].iobase == 0 &&
2168 ports[idx].membase == NULL))
2169 for (idx = 0; idx < nr; idx++)
2170 if (ports[idx].iobase != 0 ||
2171 ports[idx].membase != NULL)
2172 break;
2173
2174 co->index = idx;
2175
2176 return ports + idx;
2177}
2178
2179/**
2180 * uart_parse_earlycon - Parse earlycon options
2181 * @p: ptr to 2nd field (ie., just beyond '<name>,')
2182 * @iotype: ptr for decoded iotype (out)
2183 * @addr: ptr for decoded mapbase/iobase (out)
2184 * @options: ptr for <options> field; %NULL if not present (out)
2185 *
2186 * Decodes earlycon kernel command line parameters of the form:
2187 * * earlycon=<name>,io|mmio|mmio16|mmio32|mmio32be|mmio32native,<addr>,<options>
2188 * * console=<name>,io|mmio|mmio16|mmio32|mmio32be|mmio32native,<addr>,<options>
2189 *
2190 * The optional form:
2191 * * earlycon=<name>,0x<addr>,<options>
2192 * * console=<name>,0x<addr>,<options>
2193 *
2194 * is also accepted; the returned @iotype will be %UPIO_MEM.
2195 *
2196 * Returns: 0 on success or -%EINVAL on failure
2197 */
2198int uart_parse_earlycon(char *p, unsigned char *iotype, resource_size_t *addr,
2199 char **options)
2200{
2201 if (strncmp(p, "mmio,", 5) == 0) {
2202 *iotype = UPIO_MEM;
2203 p += 5;
2204 } else if (strncmp(p, "mmio16,", 7) == 0) {
2205 *iotype = UPIO_MEM16;
2206 p += 7;
2207 } else if (strncmp(p, "mmio32,", 7) == 0) {
2208 *iotype = UPIO_MEM32;
2209 p += 7;
2210 } else if (strncmp(p, "mmio32be,", 9) == 0) {
2211 *iotype = UPIO_MEM32BE;
2212 p += 9;
2213 } else if (strncmp(p, "mmio32native,", 13) == 0) {
2214 *iotype = IS_ENABLED(CONFIG_CPU_BIG_ENDIAN) ?
2215 UPIO_MEM32BE : UPIO_MEM32;
2216 p += 13;
2217 } else if (strncmp(p, "io,", 3) == 0) {
2218 *iotype = UPIO_PORT;
2219 p += 3;
2220 } else if (strncmp(p, "0x", 2) == 0) {
2221 *iotype = UPIO_MEM;
2222 } else {
2223 return -EINVAL;
2224 }
2225
2226 /*
2227 * Before you replace it with kstrtoull(), think about options separator
2228 * (',') it will not tolerate
2229 */
2230 *addr = simple_strtoull(p, NULL, 0);
2231 p = strchr(p, ',');
2232 if (p)
2233 p++;
2234
2235 *options = p;
2236 return 0;
2237}
2238EXPORT_SYMBOL_GPL(uart_parse_earlycon);
2239
2240/**
2241 * uart_parse_options - Parse serial port baud/parity/bits/flow control.
2242 * @options: pointer to option string
2243 * @baud: pointer to an 'int' variable for the baud rate.
2244 * @parity: pointer to an 'int' variable for the parity.
2245 * @bits: pointer to an 'int' variable for the number of data bits.
2246 * @flow: pointer to an 'int' variable for the flow control character.
2247 *
2248 * uart_parse_options() decodes a string containing the serial console
2249 * options. The format of the string is <baud><parity><bits><flow>,
2250 * eg: 115200n8r
2251 */
2252void
2253uart_parse_options(const char *options, int *baud, int *parity,
2254 int *bits, int *flow)
2255{
2256 const char *s = options;
2257
2258 *baud = simple_strtoul(s, NULL, 10);
2259 while (*s >= '0' && *s <= '9')
2260 s++;
2261 if (*s)
2262 *parity = *s++;
2263 if (*s)
2264 *bits = *s++ - '0';
2265 if (*s)
2266 *flow = *s;
2267}
2268EXPORT_SYMBOL_GPL(uart_parse_options);
2269
2270/**
2271 * uart_set_options - setup the serial console parameters
2272 * @port: pointer to the serial ports uart_port structure
2273 * @co: console pointer
2274 * @baud: baud rate
2275 * @parity: parity character - 'n' (none), 'o' (odd), 'e' (even)
2276 * @bits: number of data bits
2277 * @flow: flow control character - 'r' (rts)
2278 *
2279 * Locking: Caller must hold console_list_lock in order to serialize
2280 * early initialization of the serial-console lock.
2281 */
2282int
2283uart_set_options(struct uart_port *port, struct console *co,
2284 int baud, int parity, int bits, int flow)
2285{
2286 struct ktermios termios;
2287 static struct ktermios dummy;
2288
2289 /*
2290 * Ensure that the serial-console lock is initialised early.
2291 *
2292 * Note that the console-registered check is needed because
2293 * kgdboc can call uart_set_options() for an already registered
2294 * console via tty_find_polling_driver() and uart_poll_init().
2295 */
2296 if (!uart_console_registered_locked(port) && !port->console_reinit)
2297 uart_port_spin_lock_init(port);
2298
2299 memset(&termios, 0, sizeof(struct ktermios));
2300
2301 termios.c_cflag |= CREAD | HUPCL | CLOCAL;
2302 tty_termios_encode_baud_rate(&termios, baud, baud);
2303
2304 if (bits == 7)
2305 termios.c_cflag |= CS7;
2306 else
2307 termios.c_cflag |= CS8;
2308
2309 switch (parity) {
2310 case 'o': case 'O':
2311 termios.c_cflag |= PARODD;
2312 fallthrough;
2313 case 'e': case 'E':
2314 termios.c_cflag |= PARENB;
2315 break;
2316 }
2317
2318 if (flow == 'r')
2319 termios.c_cflag |= CRTSCTS;
2320
2321 /*
2322 * some uarts on other side don't support no flow control.
2323 * So we set * DTR in host uart to make them happy
2324 */
2325 port->mctrl |= TIOCM_DTR;
2326
2327 port->ops->set_termios(port, &termios, &dummy);
2328 /*
2329 * Allow the setting of the UART parameters with a NULL console
2330 * too:
2331 */
2332 if (co) {
2333 co->cflag = termios.c_cflag;
2334 co->ispeed = termios.c_ispeed;
2335 co->ospeed = termios.c_ospeed;
2336 }
2337
2338 return 0;
2339}
2340EXPORT_SYMBOL_GPL(uart_set_options);
2341#endif /* CONFIG_SERIAL_CORE_CONSOLE */
2342
2343/**
2344 * uart_change_pm - set power state of the port
2345 *
2346 * @state: port descriptor
2347 * @pm_state: new state
2348 *
2349 * Locking: port->mutex has to be held
2350 */
2351static void uart_change_pm(struct uart_state *state,
2352 enum uart_pm_state pm_state)
2353{
2354 struct uart_port *port = uart_port_check(state);
2355
2356 if (state->pm_state != pm_state) {
2357 if (port && port->ops->pm)
2358 port->ops->pm(port, pm_state, state->pm_state);
2359 state->pm_state = pm_state;
2360 }
2361}
2362
2363struct uart_match {
2364 struct uart_port *port;
2365 struct uart_driver *driver;
2366};
2367
2368static int serial_match_port(struct device *dev, void *data)
2369{
2370 struct uart_match *match = data;
2371 struct tty_driver *tty_drv = match->driver->tty_driver;
2372 dev_t devt = MKDEV(tty_drv->major, tty_drv->minor_start) +
2373 match->port->line;
2374
2375 return dev->devt == devt; /* Actually, only one tty per port */
2376}
2377
2378int uart_suspend_port(struct uart_driver *drv, struct uart_port *uport)
2379{
2380 struct uart_state *state = drv->state + uport->line;
2381 struct tty_port *port = &state->port;
2382 struct device *tty_dev;
2383 struct uart_match match = {uport, drv};
2384
2385 guard(mutex)(&port->mutex);
2386
2387 tty_dev = device_find_child(&uport->port_dev->dev, &match, serial_match_port);
2388 if (tty_dev && device_may_wakeup(tty_dev)) {
2389 enable_irq_wake(uport->irq);
2390 put_device(tty_dev);
2391 return 0;
2392 }
2393 put_device(tty_dev);
2394
2395 /*
2396 * Nothing to do if the console is not suspending
2397 * except stop_rx to prevent any asynchronous data
2398 * over RX line. However ensure that we will be
2399 * able to Re-start_rx later.
2400 */
2401 if (!console_suspend_enabled && uart_console(uport)) {
2402 if (uport->ops->start_rx) {
2403 uart_port_lock_irq(uport);
2404 uport->ops->stop_rx(uport);
2405 uart_port_unlock_irq(uport);
2406 }
2407 device_set_awake_path(uport->dev);
2408 return 0;
2409 }
2410
2411 uport->suspended = 1;
2412
2413 if (tty_port_initialized(port)) {
2414 const struct uart_ops *ops = uport->ops;
2415 int tries;
2416 unsigned int mctrl;
2417
2418 tty_port_set_suspended(port, true);
2419 tty_port_set_initialized(port, false);
2420
2421 uart_port_lock_irq(uport);
2422 ops->stop_tx(uport);
2423 if (!(uport->rs485.flags & SER_RS485_ENABLED))
2424 ops->set_mctrl(uport, 0);
2425 /* save mctrl so it can be restored on resume */
2426 mctrl = uport->mctrl;
2427 uport->mctrl = 0;
2428 ops->stop_rx(uport);
2429 uart_port_unlock_irq(uport);
2430
2431 /*
2432 * Wait for the transmitter to empty.
2433 */
2434 for (tries = 3; !ops->tx_empty(uport) && tries; tries--)
2435 msleep(10);
2436 if (!tries)
2437 dev_err(uport->dev, "%s: Unable to drain transmitter\n",
2438 uport->name);
2439
2440 ops->shutdown(uport);
2441 uport->mctrl = mctrl;
2442 }
2443
2444 /*
2445 * Disable the console device before suspending.
2446 */
2447 if (uart_console(uport))
2448 console_stop(uport->cons);
2449
2450 uart_change_pm(state, UART_PM_STATE_OFF);
2451
2452 return 0;
2453}
2454EXPORT_SYMBOL(uart_suspend_port);
2455
2456int uart_resume_port(struct uart_driver *drv, struct uart_port *uport)
2457{
2458 struct uart_state *state = drv->state + uport->line;
2459 struct tty_port *port = &state->port;
2460 struct device *tty_dev;
2461 struct uart_match match = {uport, drv};
2462 struct ktermios termios;
2463
2464 guard(mutex)(&port->mutex);
2465
2466 tty_dev = device_find_child(&uport->port_dev->dev, &match, serial_match_port);
2467 if (!uport->suspended && device_may_wakeup(tty_dev)) {
2468 if (irqd_is_wakeup_set(irq_get_irq_data((uport->irq))))
2469 disable_irq_wake(uport->irq);
2470 put_device(tty_dev);
2471 return 0;
2472 }
2473 put_device(tty_dev);
2474 uport->suspended = 0;
2475
2476 /*
2477 * Re-enable the console device after suspending.
2478 */
2479 if (uart_console(uport)) {
2480 /*
2481 * First try to use the console cflag setting.
2482 */
2483 memset(&termios, 0, sizeof(struct ktermios));
2484 termios.c_cflag = uport->cons->cflag;
2485 termios.c_ispeed = uport->cons->ispeed;
2486 termios.c_ospeed = uport->cons->ospeed;
2487
2488 /*
2489 * If that's unset, use the tty termios setting.
2490 */
2491 if (port->tty && termios.c_cflag == 0)
2492 termios = port->tty->termios;
2493
2494 if (console_suspend_enabled)
2495 uart_change_pm(state, UART_PM_STATE_ON);
2496 uport->ops->set_termios(uport, &termios, NULL);
2497 if (!console_suspend_enabled && uport->ops->start_rx) {
2498 uart_port_lock_irq(uport);
2499 uport->ops->start_rx(uport);
2500 uart_port_unlock_irq(uport);
2501 }
2502 if (console_suspend_enabled)
2503 console_start(uport->cons);
2504 }
2505
2506 if (tty_port_suspended(port)) {
2507 const struct uart_ops *ops = uport->ops;
2508 int ret;
2509
2510 uart_change_pm(state, UART_PM_STATE_ON);
2511 uart_port_lock_irq(uport);
2512 if (!(uport->rs485.flags & SER_RS485_ENABLED))
2513 ops->set_mctrl(uport, 0);
2514 uart_port_unlock_irq(uport);
2515 if (console_suspend_enabled || !uart_console(uport)) {
2516 /* Protected by port mutex for now */
2517 struct tty_struct *tty = port->tty;
2518
2519 ret = ops->startup(uport);
2520 if (ret == 0) {
2521 if (tty)
2522 uart_change_line_settings(tty, state, NULL);
2523 uart_rs485_config(uport);
2524 uart_port_lock_irq(uport);
2525 if (!(uport->rs485.flags & SER_RS485_ENABLED))
2526 ops->set_mctrl(uport, uport->mctrl);
2527 ops->start_tx(uport);
2528 uart_port_unlock_irq(uport);
2529 tty_port_set_initialized(port, true);
2530 } else {
2531 /*
2532 * Failed to resume - maybe hardware went away?
2533 * Clear the "initialized" flag so we won't try
2534 * to call the low level drivers shutdown method.
2535 */
2536 uart_shutdown(tty, state);
2537 }
2538 }
2539
2540 tty_port_set_suspended(port, false);
2541 }
2542
2543 return 0;
2544}
2545EXPORT_SYMBOL(uart_resume_port);
2546
2547static inline void
2548uart_report_port(struct uart_driver *drv, struct uart_port *port)
2549{
2550 char address[64];
2551
2552 switch (port->iotype) {
2553 case UPIO_PORT:
2554 snprintf(address, sizeof(address), "I/O 0x%lx", port->iobase);
2555 break;
2556 case UPIO_HUB6:
2557 snprintf(address, sizeof(address),
2558 "I/O 0x%lx offset 0x%x", port->iobase, port->hub6);
2559 break;
2560 case UPIO_MEM:
2561 case UPIO_MEM16:
2562 case UPIO_MEM32:
2563 case UPIO_MEM32BE:
2564 case UPIO_AU:
2565 case UPIO_TSI:
2566 snprintf(address, sizeof(address),
2567 "MMIO 0x%llx", (unsigned long long)port->mapbase);
2568 break;
2569 default:
2570 strscpy(address, "*unknown*", sizeof(address));
2571 break;
2572 }
2573
2574 pr_info("%s%s%s at %s (irq = %d, base_baud = %d) is a %s\n",
2575 port->dev ? dev_name(port->dev) : "",
2576 port->dev ? ": " : "",
2577 port->name,
2578 address, port->irq, port->uartclk / 16, uart_type(port));
2579
2580 /* The magic multiplier feature is a bit obscure, so report it too. */
2581 if (port->flags & UPF_MAGIC_MULTIPLIER)
2582 pr_info("%s%s%s extra baud rates supported: %d, %d",
2583 port->dev ? dev_name(port->dev) : "",
2584 port->dev ? ": " : "",
2585 port->name,
2586 port->uartclk / 8, port->uartclk / 4);
2587}
2588
2589static void
2590uart_configure_port(struct uart_driver *drv, struct uart_state *state,
2591 struct uart_port *port)
2592{
2593 unsigned int flags;
2594
2595 /*
2596 * If there isn't a port here, don't do anything further.
2597 */
2598 if (!port->iobase && !port->mapbase && !port->membase)
2599 return;
2600
2601 /*
2602 * Now do the auto configuration stuff. Note that config_port
2603 * is expected to claim the resources and map the port for us.
2604 */
2605 flags = 0;
2606 if (port->flags & UPF_AUTO_IRQ)
2607 flags |= UART_CONFIG_IRQ;
2608 if (port->flags & UPF_BOOT_AUTOCONF) {
2609 if (!(port->flags & UPF_FIXED_TYPE)) {
2610 port->type = PORT_UNKNOWN;
2611 flags |= UART_CONFIG_TYPE;
2612 }
2613 /* Synchronize with possible boot console. */
2614 if (uart_console(port))
2615 console_lock();
2616 port->ops->config_port(port, flags);
2617 if (uart_console(port))
2618 console_unlock();
2619 }
2620
2621 if (port->type != PORT_UNKNOWN) {
2622 unsigned long flags;
2623
2624 uart_report_port(drv, port);
2625
2626 /* Synchronize with possible boot console. */
2627 if (uart_console(port))
2628 console_lock();
2629
2630 /* Power up port for set_mctrl() */
2631 uart_change_pm(state, UART_PM_STATE_ON);
2632
2633 /*
2634 * Ensure that the modem control lines are de-activated.
2635 * keep the DTR setting that is set in uart_set_options()
2636 * We probably don't need a spinlock around this, but
2637 */
2638 uart_port_lock_irqsave(port, &flags);
2639 port->mctrl &= TIOCM_DTR;
2640 if (!(port->rs485.flags & SER_RS485_ENABLED))
2641 port->ops->set_mctrl(port, port->mctrl);
2642 uart_port_unlock_irqrestore(port, flags);
2643
2644 uart_rs485_config(port);
2645
2646 if (uart_console(port))
2647 console_unlock();
2648
2649 /*
2650 * If this driver supports console, and it hasn't been
2651 * successfully registered yet, try to re-register it.
2652 * It may be that the port was not available.
2653 */
2654 if (port->cons && !console_is_registered(port->cons))
2655 register_console(port->cons);
2656
2657 /*
2658 * Power down all ports by default, except the
2659 * console if we have one.
2660 */
2661 if (!uart_console(port))
2662 uart_change_pm(state, UART_PM_STATE_OFF);
2663 }
2664}
2665
2666#ifdef CONFIG_CONSOLE_POLL
2667
2668static int uart_poll_init(struct tty_driver *driver, int line, char *options)
2669{
2670 struct uart_driver *drv = driver->driver_state;
2671 struct uart_state *state = drv->state + line;
2672 enum uart_pm_state pm_state;
2673 struct tty_port *tport;
2674 struct uart_port *port;
2675 int baud = 9600;
2676 int bits = 8;
2677 int parity = 'n';
2678 int flow = 'n';
2679 int ret = 0;
2680
2681 tport = &state->port;
2682
2683 guard(mutex)(&tport->mutex);
2684
2685 port = uart_port_check(state);
2686 if (!port || port->type == PORT_UNKNOWN ||
2687 !(port->ops->poll_get_char && port->ops->poll_put_char))
2688 return -1;
2689
2690 pm_state = state->pm_state;
2691 uart_change_pm(state, UART_PM_STATE_ON);
2692
2693 if (port->ops->poll_init) {
2694 /*
2695 * We don't set initialized as we only initialized the hw,
2696 * e.g. state->xmit is still uninitialized.
2697 */
2698 if (!tty_port_initialized(tport))
2699 ret = port->ops->poll_init(port);
2700 }
2701
2702 if (!ret && options) {
2703 uart_parse_options(options, &baud, &parity, &bits, &flow);
2704 console_list_lock();
2705 ret = uart_set_options(port, NULL, baud, parity, bits, flow);
2706 console_list_unlock();
2707 }
2708
2709 if (ret)
2710 uart_change_pm(state, pm_state);
2711
2712 return ret;
2713}
2714
2715static int uart_poll_get_char(struct tty_driver *driver, int line)
2716{
2717 struct uart_driver *drv = driver->driver_state;
2718 struct uart_state *state = drv->state + line;
2719 struct uart_port *port;
2720 int ret = -1;
2721
2722 port = uart_port_ref(state);
2723 if (port) {
2724 ret = port->ops->poll_get_char(port);
2725 uart_port_deref(port);
2726 }
2727
2728 return ret;
2729}
2730
2731static void uart_poll_put_char(struct tty_driver *driver, int line, char ch)
2732{
2733 struct uart_driver *drv = driver->driver_state;
2734 struct uart_state *state = drv->state + line;
2735 struct uart_port *port;
2736
2737 port = uart_port_ref(state);
2738 if (!port)
2739 return;
2740
2741 if (ch == '\n')
2742 port->ops->poll_put_char(port, '\r');
2743 port->ops->poll_put_char(port, ch);
2744 uart_port_deref(port);
2745}
2746#endif
2747
2748static const struct tty_operations uart_ops = {
2749 .install = uart_install,
2750 .open = uart_open,
2751 .close = uart_close,
2752 .write = uart_write,
2753 .put_char = uart_put_char,
2754 .flush_chars = uart_flush_chars,
2755 .write_room = uart_write_room,
2756 .chars_in_buffer= uart_chars_in_buffer,
2757 .flush_buffer = uart_flush_buffer,
2758 .ioctl = uart_ioctl,
2759 .throttle = uart_throttle,
2760 .unthrottle = uart_unthrottle,
2761 .send_xchar = uart_send_xchar,
2762 .set_termios = uart_set_termios,
2763 .set_ldisc = uart_set_ldisc,
2764 .stop = uart_stop,
2765 .start = uart_start,
2766 .hangup = uart_hangup,
2767 .break_ctl = uart_break_ctl,
2768 .wait_until_sent= uart_wait_until_sent,
2769#ifdef CONFIG_PROC_FS
2770 .proc_show = uart_proc_show,
2771#endif
2772 .tiocmget = uart_tiocmget,
2773 .tiocmset = uart_tiocmset,
2774 .set_serial = uart_set_info_user,
2775 .get_serial = uart_get_info_user,
2776 .get_icount = uart_get_icount,
2777#ifdef CONFIG_CONSOLE_POLL
2778 .poll_init = uart_poll_init,
2779 .poll_get_char = uart_poll_get_char,
2780 .poll_put_char = uart_poll_put_char,
2781#endif
2782};
2783
2784static const struct tty_port_operations uart_port_ops = {
2785 .carrier_raised = uart_carrier_raised,
2786 .dtr_rts = uart_dtr_rts,
2787 .activate = uart_port_activate,
2788 .shutdown = uart_tty_port_shutdown,
2789};
2790
2791/**
2792 * uart_register_driver - register a driver with the uart core layer
2793 * @drv: low level driver structure
2794 *
2795 * Register a uart driver with the core driver. We in turn register with the
2796 * tty layer, and initialise the core driver per-port state.
2797 *
2798 * We have a proc file in /proc/tty/driver which is named after the normal
2799 * driver.
2800 *
2801 * @drv->port should be %NULL, and the per-port structures should be registered
2802 * using uart_add_one_port() after this call has succeeded.
2803 *
2804 * Locking: none, Interrupts: enabled
2805 */
2806int uart_register_driver(struct uart_driver *drv)
2807{
2808 struct tty_driver *normal;
2809 int i, retval = -ENOMEM;
2810
2811 BUG_ON(drv->state);
2812
2813 /*
2814 * Maybe we should be using a slab cache for this, especially if
2815 * we have a large number of ports to handle.
2816 */
2817 drv->state = kcalloc(drv->nr, sizeof(struct uart_state), GFP_KERNEL);
2818 if (!drv->state)
2819 goto out;
2820
2821 normal = tty_alloc_driver(drv->nr, TTY_DRIVER_REAL_RAW |
2822 TTY_DRIVER_DYNAMIC_DEV);
2823 if (IS_ERR(normal)) {
2824 retval = PTR_ERR(normal);
2825 goto out_kfree;
2826 }
2827
2828 drv->tty_driver = normal;
2829
2830 normal->driver_name = drv->driver_name;
2831 normal->name = drv->dev_name;
2832 normal->major = drv->major;
2833 normal->minor_start = drv->minor;
2834 normal->type = TTY_DRIVER_TYPE_SERIAL;
2835 normal->subtype = SERIAL_TYPE_NORMAL;
2836 normal->init_termios = tty_std_termios;
2837 normal->init_termios.c_cflag = B9600 | CS8 | CREAD | HUPCL | CLOCAL;
2838 normal->init_termios.c_ispeed = normal->init_termios.c_ospeed = 9600;
2839 normal->driver_state = drv;
2840 tty_set_operations(normal, &uart_ops);
2841
2842 /*
2843 * Initialise the UART state(s).
2844 */
2845 for (i = 0; i < drv->nr; i++) {
2846 struct uart_state *state = drv->state + i;
2847 struct tty_port *port = &state->port;
2848
2849 tty_port_init(port);
2850 port->ops = &uart_port_ops;
2851 }
2852
2853 retval = tty_register_driver(normal);
2854 if (retval >= 0)
2855 return retval;
2856
2857 for (i = 0; i < drv->nr; i++)
2858 tty_port_destroy(&drv->state[i].port);
2859 tty_driver_kref_put(normal);
2860out_kfree:
2861 kfree(drv->state);
2862out:
2863 return retval;
2864}
2865EXPORT_SYMBOL(uart_register_driver);
2866
2867/**
2868 * uart_unregister_driver - remove a driver from the uart core layer
2869 * @drv: low level driver structure
2870 *
2871 * Remove all references to a driver from the core driver. The low level
2872 * driver must have removed all its ports via the uart_remove_one_port() if it
2873 * registered them with uart_add_one_port(). (I.e. @drv->port is %NULL.)
2874 *
2875 * Locking: none, Interrupts: enabled
2876 */
2877void uart_unregister_driver(struct uart_driver *drv)
2878{
2879 struct tty_driver *p = drv->tty_driver;
2880 unsigned int i;
2881
2882 tty_unregister_driver(p);
2883 tty_driver_kref_put(p);
2884 for (i = 0; i < drv->nr; i++)
2885 tty_port_destroy(&drv->state[i].port);
2886 kfree(drv->state);
2887 drv->state = NULL;
2888 drv->tty_driver = NULL;
2889}
2890EXPORT_SYMBOL(uart_unregister_driver);
2891
2892struct tty_driver *uart_console_device(struct console *co, int *index)
2893{
2894 struct uart_driver *p = co->data;
2895 *index = co->index;
2896 return p->tty_driver;
2897}
2898EXPORT_SYMBOL_GPL(uart_console_device);
2899
2900static ssize_t uartclk_show(struct device *dev,
2901 struct device_attribute *attr, char *buf)
2902{
2903 struct serial_struct tmp;
2904 struct tty_port *port = dev_get_drvdata(dev);
2905
2906 uart_get_info(port, &tmp);
2907 return sprintf(buf, "%d\n", tmp.baud_base * 16);
2908}
2909
2910static ssize_t type_show(struct device *dev,
2911 struct device_attribute *attr, char *buf)
2912{
2913 struct serial_struct tmp;
2914 struct tty_port *port = dev_get_drvdata(dev);
2915
2916 uart_get_info(port, &tmp);
2917 return sprintf(buf, "%d\n", tmp.type);
2918}
2919
2920static ssize_t line_show(struct device *dev,
2921 struct device_attribute *attr, char *buf)
2922{
2923 struct serial_struct tmp;
2924 struct tty_port *port = dev_get_drvdata(dev);
2925
2926 uart_get_info(port, &tmp);
2927 return sprintf(buf, "%d\n", tmp.line);
2928}
2929
2930static ssize_t port_show(struct device *dev,
2931 struct device_attribute *attr, char *buf)
2932{
2933 struct serial_struct tmp;
2934 struct tty_port *port = dev_get_drvdata(dev);
2935 unsigned long ioaddr;
2936
2937 uart_get_info(port, &tmp);
2938 ioaddr = tmp.port;
2939 if (HIGH_BITS_OFFSET)
2940 ioaddr |= (unsigned long)tmp.port_high << HIGH_BITS_OFFSET;
2941 return sprintf(buf, "0x%lX\n", ioaddr);
2942}
2943
2944static ssize_t irq_show(struct device *dev,
2945 struct device_attribute *attr, char *buf)
2946{
2947 struct serial_struct tmp;
2948 struct tty_port *port = dev_get_drvdata(dev);
2949
2950 uart_get_info(port, &tmp);
2951 return sprintf(buf, "%d\n", tmp.irq);
2952}
2953
2954static ssize_t flags_show(struct device *dev,
2955 struct device_attribute *attr, char *buf)
2956{
2957 struct serial_struct tmp;
2958 struct tty_port *port = dev_get_drvdata(dev);
2959
2960 uart_get_info(port, &tmp);
2961 return sprintf(buf, "0x%X\n", tmp.flags);
2962}
2963
2964static ssize_t xmit_fifo_size_show(struct device *dev,
2965 struct device_attribute *attr, char *buf)
2966{
2967 struct serial_struct tmp;
2968 struct tty_port *port = dev_get_drvdata(dev);
2969
2970 uart_get_info(port, &tmp);
2971 return sprintf(buf, "%d\n", tmp.xmit_fifo_size);
2972}
2973
2974static ssize_t close_delay_show(struct device *dev,
2975 struct device_attribute *attr, char *buf)
2976{
2977 struct serial_struct tmp;
2978 struct tty_port *port = dev_get_drvdata(dev);
2979
2980 uart_get_info(port, &tmp);
2981 return sprintf(buf, "%d\n", tmp.close_delay);
2982}
2983
2984static ssize_t closing_wait_show(struct device *dev,
2985 struct device_attribute *attr, char *buf)
2986{
2987 struct serial_struct tmp;
2988 struct tty_port *port = dev_get_drvdata(dev);
2989
2990 uart_get_info(port, &tmp);
2991 return sprintf(buf, "%d\n", tmp.closing_wait);
2992}
2993
2994static ssize_t custom_divisor_show(struct device *dev,
2995 struct device_attribute *attr, char *buf)
2996{
2997 struct serial_struct tmp;
2998 struct tty_port *port = dev_get_drvdata(dev);
2999
3000 uart_get_info(port, &tmp);
3001 return sprintf(buf, "%d\n", tmp.custom_divisor);
3002}
3003
3004static ssize_t io_type_show(struct device *dev,
3005 struct device_attribute *attr, char *buf)
3006{
3007 struct serial_struct tmp;
3008 struct tty_port *port = dev_get_drvdata(dev);
3009
3010 uart_get_info(port, &tmp);
3011 return sprintf(buf, "%d\n", tmp.io_type);
3012}
3013
3014static ssize_t iomem_base_show(struct device *dev,
3015 struct device_attribute *attr, char *buf)
3016{
3017 struct serial_struct tmp;
3018 struct tty_port *port = dev_get_drvdata(dev);
3019
3020 uart_get_info(port, &tmp);
3021 return sprintf(buf, "0x%lX\n", (unsigned long)tmp.iomem_base);
3022}
3023
3024static ssize_t iomem_reg_shift_show(struct device *dev,
3025 struct device_attribute *attr, char *buf)
3026{
3027 struct serial_struct tmp;
3028 struct tty_port *port = dev_get_drvdata(dev);
3029
3030 uart_get_info(port, &tmp);
3031 return sprintf(buf, "%d\n", tmp.iomem_reg_shift);
3032}
3033
3034static ssize_t console_show(struct device *dev,
3035 struct device_attribute *attr, char *buf)
3036{
3037 struct tty_port *port = dev_get_drvdata(dev);
3038 struct uart_state *state = container_of(port, struct uart_state, port);
3039 struct uart_port *uport;
3040 bool console = false;
3041
3042 mutex_lock(&port->mutex);
3043 uport = uart_port_check(state);
3044 if (uport)
3045 console = uart_console_registered(uport);
3046 mutex_unlock(&port->mutex);
3047
3048 return sprintf(buf, "%c\n", console ? 'Y' : 'N');
3049}
3050
3051static ssize_t console_store(struct device *dev,
3052 struct device_attribute *attr, const char *buf, size_t count)
3053{
3054 struct tty_port *port = dev_get_drvdata(dev);
3055 struct uart_state *state = container_of(port, struct uart_state, port);
3056 struct uart_port *uport;
3057 bool oldconsole, newconsole;
3058 int ret;
3059
3060 ret = kstrtobool(buf, &newconsole);
3061 if (ret)
3062 return ret;
3063
3064 mutex_lock(&port->mutex);
3065 uport = uart_port_check(state);
3066 if (uport) {
3067 oldconsole = uart_console_registered(uport);
3068 if (oldconsole && !newconsole) {
3069 ret = unregister_console(uport->cons);
3070 } else if (!oldconsole && newconsole) {
3071 if (uart_console(uport)) {
3072 uport->console_reinit = 1;
3073 register_console(uport->cons);
3074 } else {
3075 ret = -ENOENT;
3076 }
3077 }
3078 } else {
3079 ret = -ENXIO;
3080 }
3081 mutex_unlock(&port->mutex);
3082
3083 return ret < 0 ? ret : count;
3084}
3085
3086static DEVICE_ATTR_RO(uartclk);
3087static DEVICE_ATTR_RO(type);
3088static DEVICE_ATTR_RO(line);
3089static DEVICE_ATTR_RO(port);
3090static DEVICE_ATTR_RO(irq);
3091static DEVICE_ATTR_RO(flags);
3092static DEVICE_ATTR_RO(xmit_fifo_size);
3093static DEVICE_ATTR_RO(close_delay);
3094static DEVICE_ATTR_RO(closing_wait);
3095static DEVICE_ATTR_RO(custom_divisor);
3096static DEVICE_ATTR_RO(io_type);
3097static DEVICE_ATTR_RO(iomem_base);
3098static DEVICE_ATTR_RO(iomem_reg_shift);
3099static DEVICE_ATTR_RW(console);
3100
3101static struct attribute *tty_dev_attrs[] = {
3102 &dev_attr_uartclk.attr,
3103 &dev_attr_type.attr,
3104 &dev_attr_line.attr,
3105 &dev_attr_port.attr,
3106 &dev_attr_irq.attr,
3107 &dev_attr_flags.attr,
3108 &dev_attr_xmit_fifo_size.attr,
3109 &dev_attr_close_delay.attr,
3110 &dev_attr_closing_wait.attr,
3111 &dev_attr_custom_divisor.attr,
3112 &dev_attr_io_type.attr,
3113 &dev_attr_iomem_base.attr,
3114 &dev_attr_iomem_reg_shift.attr,
3115 &dev_attr_console.attr,
3116 NULL
3117};
3118
3119static const struct attribute_group tty_dev_attr_group = {
3120 .attrs = tty_dev_attrs,
3121};
3122
3123/**
3124 * serial_core_add_one_port - attach a driver-defined port structure
3125 * @drv: pointer to the uart low level driver structure for this port
3126 * @uport: uart port structure to use for this port.
3127 *
3128 * Context: task context, might sleep
3129 *
3130 * This allows the driver @drv to register its own uart_port structure with the
3131 * core driver. The main purpose is to allow the low level uart drivers to
3132 * expand uart_port, rather than having yet more levels of structures.
3133 * Caller must hold port_mutex.
3134 */
3135static int serial_core_add_one_port(struct uart_driver *drv, struct uart_port *uport)
3136{
3137 struct uart_state *state;
3138 struct tty_port *port;
3139 int ret = 0;
3140 struct device *tty_dev;
3141 int num_groups;
3142
3143 if (uport->line >= drv->nr)
3144 return -EINVAL;
3145
3146 state = drv->state + uport->line;
3147 port = &state->port;
3148
3149 mutex_lock(&port->mutex);
3150 if (state->uart_port) {
3151 ret = -EINVAL;
3152 goto out;
3153 }
3154
3155 /* Link the port to the driver state table and vice versa */
3156 atomic_set(&state->refcount, 1);
3157 init_waitqueue_head(&state->remove_wait);
3158 state->uart_port = uport;
3159 uport->state = state;
3160
3161 /*
3162 * If this port is in use as a console then the spinlock is already
3163 * initialised.
3164 */
3165 if (!uart_console_registered(uport))
3166 uart_port_spin_lock_init(uport);
3167
3168 state->pm_state = UART_PM_STATE_UNDEFINED;
3169 uart_port_set_cons(uport, drv->cons);
3170 uport->minor = drv->tty_driver->minor_start + uport->line;
3171 uport->name = kasprintf(GFP_KERNEL, "%s%d", drv->dev_name,
3172 drv->tty_driver->name_base + uport->line);
3173 if (!uport->name) {
3174 ret = -ENOMEM;
3175 goto out;
3176 }
3177
3178 if (uport->cons && uport->dev)
3179 of_console_check(uport->dev->of_node, uport->cons->name, uport->line);
3180
3181 tty_port_link_device(port, drv->tty_driver, uport->line);
3182 uart_configure_port(drv, state, uport);
3183
3184 port->console = uart_console(uport);
3185
3186 num_groups = 2;
3187 if (uport->attr_group)
3188 num_groups++;
3189
3190 uport->tty_groups = kcalloc(num_groups, sizeof(*uport->tty_groups),
3191 GFP_KERNEL);
3192 if (!uport->tty_groups) {
3193 ret = -ENOMEM;
3194 goto out;
3195 }
3196 uport->tty_groups[0] = &tty_dev_attr_group;
3197 if (uport->attr_group)
3198 uport->tty_groups[1] = uport->attr_group;
3199
3200 /* Ensure serdev drivers can call serdev_device_open() right away */
3201 uport->flags &= ~UPF_DEAD;
3202
3203 /*
3204 * Register the port whether it's detected or not. This allows
3205 * setserial to be used to alter this port's parameters.
3206 */
3207 tty_dev = tty_port_register_device_attr_serdev(port, drv->tty_driver,
3208 uport->line, uport->dev, &uport->port_dev->dev, port,
3209 uport->tty_groups);
3210 if (!IS_ERR(tty_dev)) {
3211 device_set_wakeup_capable(tty_dev, 1);
3212 } else {
3213 uport->flags |= UPF_DEAD;
3214 dev_err(uport->dev, "Cannot register tty device on line %d\n",
3215 uport->line);
3216 }
3217
3218 out:
3219 mutex_unlock(&port->mutex);
3220
3221 return ret;
3222}
3223
3224/**
3225 * serial_core_remove_one_port - detach a driver defined port structure
3226 * @drv: pointer to the uart low level driver structure for this port
3227 * @uport: uart port structure for this port
3228 *
3229 * Context: task context, might sleep
3230 *
3231 * This unhooks (and hangs up) the specified port structure from the core
3232 * driver. No further calls will be made to the low-level code for this port.
3233 * Caller must hold port_mutex.
3234 */
3235static void serial_core_remove_one_port(struct uart_driver *drv,
3236 struct uart_port *uport)
3237{
3238 struct uart_state *state = drv->state + uport->line;
3239 struct tty_port *port = &state->port;
3240 struct uart_port *uart_port;
3241 struct tty_struct *tty;
3242
3243 mutex_lock(&port->mutex);
3244 uart_port = uart_port_check(state);
3245 if (uart_port != uport)
3246 dev_alert(uport->dev, "Removing wrong port: %p != %p\n",
3247 uart_port, uport);
3248
3249 if (!uart_port) {
3250 mutex_unlock(&port->mutex);
3251 return;
3252 }
3253 mutex_unlock(&port->mutex);
3254
3255 /*
3256 * Remove the devices from the tty layer
3257 */
3258 tty_port_unregister_device(port, drv->tty_driver, uport->line);
3259
3260 tty = tty_port_tty_get(port);
3261 if (tty) {
3262 tty_vhangup(port->tty);
3263 tty_kref_put(tty);
3264 }
3265
3266 /*
3267 * If the port is used as a console, unregister it
3268 */
3269 if (uart_console(uport))
3270 unregister_console(uport->cons);
3271
3272 /*
3273 * Free the port IO and memory resources, if any.
3274 */
3275 if (uport->type != PORT_UNKNOWN && uport->ops->release_port)
3276 uport->ops->release_port(uport);
3277 kfree(uport->tty_groups);
3278 kfree(uport->name);
3279
3280 /*
3281 * Indicate that there isn't a port here anymore.
3282 */
3283 uport->type = PORT_UNKNOWN;
3284 uport->port_dev = NULL;
3285
3286 mutex_lock(&port->mutex);
3287 WARN_ON(atomic_dec_return(&state->refcount) < 0);
3288 wait_event(state->remove_wait, !atomic_read(&state->refcount));
3289 state->uart_port = NULL;
3290 mutex_unlock(&port->mutex);
3291}
3292
3293/**
3294 * uart_match_port - are the two ports equivalent?
3295 * @port1: first port
3296 * @port2: second port
3297 *
3298 * This utility function can be used to determine whether two uart_port
3299 * structures describe the same port.
3300 */
3301bool uart_match_port(const struct uart_port *port1,
3302 const struct uart_port *port2)
3303{
3304 if (port1->iotype != port2->iotype)
3305 return false;
3306
3307 switch (port1->iotype) {
3308 case UPIO_PORT:
3309 return port1->iobase == port2->iobase;
3310 case UPIO_HUB6:
3311 return port1->iobase == port2->iobase &&
3312 port1->hub6 == port2->hub6;
3313 case UPIO_MEM:
3314 case UPIO_MEM16:
3315 case UPIO_MEM32:
3316 case UPIO_MEM32BE:
3317 case UPIO_AU:
3318 case UPIO_TSI:
3319 return port1->mapbase == port2->mapbase;
3320 }
3321
3322 return false;
3323}
3324EXPORT_SYMBOL(uart_match_port);
3325
3326static struct serial_ctrl_device *
3327serial_core_get_ctrl_dev(struct serial_port_device *port_dev)
3328{
3329 struct device *dev = &port_dev->dev;
3330
3331 return to_serial_base_ctrl_device(dev->parent);
3332}
3333
3334/*
3335 * Find a registered serial core controller device if one exists. Returns
3336 * the first device matching the ctrl_id. Caller must hold port_mutex.
3337 */
3338static struct serial_ctrl_device *serial_core_ctrl_find(struct uart_driver *drv,
3339 struct device *phys_dev,
3340 int ctrl_id)
3341{
3342 struct uart_state *state;
3343 int i;
3344
3345 lockdep_assert_held(&port_mutex);
3346
3347 for (i = 0; i < drv->nr; i++) {
3348 state = drv->state + i;
3349 if (!state->uart_port || !state->uart_port->port_dev)
3350 continue;
3351
3352 if (state->uart_port->dev == phys_dev &&
3353 state->uart_port->ctrl_id == ctrl_id)
3354 return serial_core_get_ctrl_dev(state->uart_port->port_dev);
3355 }
3356
3357 return NULL;
3358}
3359
3360static struct serial_ctrl_device *serial_core_ctrl_device_add(struct uart_port *port)
3361{
3362 return serial_base_ctrl_add(port, port->dev);
3363}
3364
3365static int serial_core_port_device_add(struct serial_ctrl_device *ctrl_dev,
3366 struct uart_port *port)
3367{
3368 struct serial_port_device *port_dev;
3369
3370 port_dev = serial_base_port_add(port, ctrl_dev);
3371 if (IS_ERR(port_dev))
3372 return PTR_ERR(port_dev);
3373
3374 port->port_dev = port_dev;
3375
3376 return 0;
3377}
3378
3379/*
3380 * Initialize a serial core port device, and a controller device if needed.
3381 */
3382int serial_core_register_port(struct uart_driver *drv, struct uart_port *port)
3383{
3384 struct serial_ctrl_device *ctrl_dev, *new_ctrl_dev = NULL;
3385 int ret;
3386
3387 mutex_lock(&port_mutex);
3388
3389 /*
3390 * Prevent serial_port_runtime_resume() from trying to use the port
3391 * until serial_core_add_one_port() has completed
3392 */
3393 port->flags |= UPF_DEAD;
3394
3395 /* Inititalize a serial core controller device if needed */
3396 ctrl_dev = serial_core_ctrl_find(drv, port->dev, port->ctrl_id);
3397 if (!ctrl_dev) {
3398 new_ctrl_dev = serial_core_ctrl_device_add(port);
3399 if (IS_ERR(new_ctrl_dev)) {
3400 ret = PTR_ERR(new_ctrl_dev);
3401 goto err_unlock;
3402 }
3403 ctrl_dev = new_ctrl_dev;
3404 }
3405
3406 /*
3407 * Initialize a serial core port device. Tag the port dead to prevent
3408 * serial_port_runtime_resume() trying to do anything until port has
3409 * been registered. It gets cleared by serial_core_add_one_port().
3410 */
3411 ret = serial_core_port_device_add(ctrl_dev, port);
3412 if (ret)
3413 goto err_unregister_ctrl_dev;
3414
3415 ret = serial_base_match_and_update_preferred_console(drv, port);
3416 if (ret)
3417 goto err_unregister_port_dev;
3418
3419 ret = serial_core_add_one_port(drv, port);
3420 if (ret)
3421 goto err_unregister_port_dev;
3422
3423 mutex_unlock(&port_mutex);
3424
3425 return 0;
3426
3427err_unregister_port_dev:
3428 serial_base_port_device_remove(port->port_dev);
3429
3430err_unregister_ctrl_dev:
3431 serial_base_ctrl_device_remove(new_ctrl_dev);
3432
3433err_unlock:
3434 mutex_unlock(&port_mutex);
3435
3436 return ret;
3437}
3438
3439/*
3440 * Removes a serial core port device, and the related serial core controller
3441 * device if the last instance.
3442 */
3443void serial_core_unregister_port(struct uart_driver *drv, struct uart_port *port)
3444{
3445 struct device *phys_dev = port->dev;
3446 struct serial_port_device *port_dev = port->port_dev;
3447 struct serial_ctrl_device *ctrl_dev = serial_core_get_ctrl_dev(port_dev);
3448 int ctrl_id = port->ctrl_id;
3449
3450 mutex_lock(&port_mutex);
3451
3452 port->flags |= UPF_DEAD;
3453
3454 serial_core_remove_one_port(drv, port);
3455
3456 /* Note that struct uart_port *port is no longer valid at this point */
3457 serial_base_port_device_remove(port_dev);
3458
3459 /* Drop the serial core controller device if no ports are using it */
3460 if (!serial_core_ctrl_find(drv, phys_dev, ctrl_id))
3461 serial_base_ctrl_device_remove(ctrl_dev);
3462
3463 mutex_unlock(&port_mutex);
3464}
3465
3466/**
3467 * uart_handle_dcd_change - handle a change of carrier detect state
3468 * @uport: uart_port structure for the open port
3469 * @active: new carrier detect status
3470 *
3471 * Caller must hold uport->lock.
3472 */
3473void uart_handle_dcd_change(struct uart_port *uport, bool active)
3474{
3475 struct tty_port *port = &uport->state->port;
3476 struct tty_struct *tty = port->tty;
3477 struct tty_ldisc *ld;
3478
3479 lockdep_assert_held_once(&uport->lock);
3480
3481 if (tty) {
3482 ld = tty_ldisc_ref(tty);
3483 if (ld) {
3484 if (ld->ops->dcd_change)
3485 ld->ops->dcd_change(tty, active);
3486 tty_ldisc_deref(ld);
3487 }
3488 }
3489
3490 uport->icount.dcd++;
3491
3492 if (uart_dcd_enabled(uport)) {
3493 if (active)
3494 wake_up_interruptible(&port->open_wait);
3495 else if (tty)
3496 tty_hangup(tty);
3497 }
3498}
3499EXPORT_SYMBOL_GPL(uart_handle_dcd_change);
3500
3501/**
3502 * uart_handle_cts_change - handle a change of clear-to-send state
3503 * @uport: uart_port structure for the open port
3504 * @active: new clear-to-send status
3505 *
3506 * Caller must hold uport->lock.
3507 */
3508void uart_handle_cts_change(struct uart_port *uport, bool active)
3509{
3510 lockdep_assert_held_once(&uport->lock);
3511
3512 uport->icount.cts++;
3513
3514 if (uart_softcts_mode(uport)) {
3515 if (uport->hw_stopped) {
3516 if (active) {
3517 uport->hw_stopped = false;
3518 uport->ops->start_tx(uport);
3519 uart_write_wakeup(uport);
3520 }
3521 } else {
3522 if (!active) {
3523 uport->hw_stopped = true;
3524 uport->ops->stop_tx(uport);
3525 }
3526 }
3527
3528 }
3529}
3530EXPORT_SYMBOL_GPL(uart_handle_cts_change);
3531
3532/**
3533 * uart_insert_char - push a char to the uart layer
3534 *
3535 * User is responsible to call tty_flip_buffer_push when they are done with
3536 * insertion.
3537 *
3538 * @port: corresponding port
3539 * @status: state of the serial port RX buffer (LSR for 8250)
3540 * @overrun: mask of overrun bits in @status
3541 * @ch: character to push
3542 * @flag: flag for the character (see TTY_NORMAL and friends)
3543 */
3544void uart_insert_char(struct uart_port *port, unsigned int status,
3545 unsigned int overrun, u8 ch, u8 flag)
3546{
3547 struct tty_port *tport = &port->state->port;
3548
3549 if ((status & port->ignore_status_mask & ~overrun) == 0)
3550 if (tty_insert_flip_char(tport, ch, flag) == 0)
3551 ++port->icount.buf_overrun;
3552
3553 /*
3554 * Overrun is special. Since it's reported immediately,
3555 * it doesn't affect the current character.
3556 */
3557 if (status & ~port->ignore_status_mask & overrun)
3558 if (tty_insert_flip_char(tport, 0, TTY_OVERRUN) == 0)
3559 ++port->icount.buf_overrun;
3560}
3561EXPORT_SYMBOL_GPL(uart_insert_char);
3562
3563#ifdef CONFIG_MAGIC_SYSRQ_SERIAL
3564static const u8 sysrq_toggle_seq[] = CONFIG_MAGIC_SYSRQ_SERIAL_SEQUENCE;
3565
3566static void uart_sysrq_on(struct work_struct *w)
3567{
3568 int sysrq_toggle_seq_len = strlen(sysrq_toggle_seq);
3569
3570 sysrq_toggle_support(1);
3571 pr_info("SysRq is enabled by magic sequence '%*pE' on serial\n",
3572 sysrq_toggle_seq_len, sysrq_toggle_seq);
3573}
3574static DECLARE_WORK(sysrq_enable_work, uart_sysrq_on);
3575
3576/**
3577 * uart_try_toggle_sysrq - Enables SysRq from serial line
3578 * @port: uart_port structure where char(s) after BREAK met
3579 * @ch: new character in the sequence after received BREAK
3580 *
3581 * Enables magic SysRq when the required sequence is met on port
3582 * (see CONFIG_MAGIC_SYSRQ_SERIAL_SEQUENCE).
3583 *
3584 * Returns: %false if @ch is out of enabling sequence and should be
3585 * handled some other way, %true if @ch was consumed.
3586 */
3587bool uart_try_toggle_sysrq(struct uart_port *port, u8 ch)
3588{
3589 int sysrq_toggle_seq_len = strlen(sysrq_toggle_seq);
3590
3591 if (!sysrq_toggle_seq_len)
3592 return false;
3593
3594 BUILD_BUG_ON(ARRAY_SIZE(sysrq_toggle_seq) >= U8_MAX);
3595 if (sysrq_toggle_seq[port->sysrq_seq] != ch) {
3596 port->sysrq_seq = 0;
3597 return false;
3598 }
3599
3600 if (++port->sysrq_seq < sysrq_toggle_seq_len) {
3601 port->sysrq = jiffies + SYSRQ_TIMEOUT;
3602 return true;
3603 }
3604
3605 schedule_work(&sysrq_enable_work);
3606
3607 port->sysrq = 0;
3608 return true;
3609}
3610EXPORT_SYMBOL_GPL(uart_try_toggle_sysrq);
3611#endif
3612
3613/**
3614 * uart_get_rs485_mode() - retrieve rs485 properties for given uart
3615 * @port: uart device's target port
3616 *
3617 * This function implements the device tree binding described in
3618 * Documentation/devicetree/bindings/serial/rs485.txt.
3619 */
3620int uart_get_rs485_mode(struct uart_port *port)
3621{
3622 struct serial_rs485 *rs485conf = &port->rs485;
3623 struct device *dev = port->dev;
3624 enum gpiod_flags dflags;
3625 struct gpio_desc *desc;
3626 u32 rs485_delay[2];
3627 int ret;
3628
3629 if (!(port->rs485_supported.flags & SER_RS485_ENABLED))
3630 return 0;
3631
3632 ret = device_property_read_u32_array(dev, "rs485-rts-delay",
3633 rs485_delay, 2);
3634 if (!ret) {
3635 rs485conf->delay_rts_before_send = rs485_delay[0];
3636 rs485conf->delay_rts_after_send = rs485_delay[1];
3637 } else {
3638 rs485conf->delay_rts_before_send = 0;
3639 rs485conf->delay_rts_after_send = 0;
3640 }
3641
3642 uart_sanitize_serial_rs485_delays(port, rs485conf);
3643
3644 /*
3645 * Clear full-duplex and enabled flags, set RTS polarity to active high
3646 * to get to a defined state with the following properties:
3647 */
3648 rs485conf->flags &= ~(SER_RS485_RX_DURING_TX | SER_RS485_ENABLED |
3649 SER_RS485_TERMINATE_BUS |
3650 SER_RS485_RTS_AFTER_SEND);
3651 rs485conf->flags |= SER_RS485_RTS_ON_SEND;
3652
3653 if (device_property_read_bool(dev, "rs485-rx-during-tx"))
3654 rs485conf->flags |= SER_RS485_RX_DURING_TX;
3655
3656 if (device_property_read_bool(dev, "linux,rs485-enabled-at-boot-time"))
3657 rs485conf->flags |= SER_RS485_ENABLED;
3658
3659 if (device_property_read_bool(dev, "rs485-rts-active-low")) {
3660 rs485conf->flags &= ~SER_RS485_RTS_ON_SEND;
3661 rs485conf->flags |= SER_RS485_RTS_AFTER_SEND;
3662 }
3663
3664 /*
3665 * Disabling termination by default is the safe choice: Else if many
3666 * bus participants enable it, no communication is possible at all.
3667 * Works fine for short cables and users may enable for longer cables.
3668 */
3669 desc = devm_gpiod_get_optional(dev, "rs485-term", GPIOD_OUT_LOW);
3670 if (IS_ERR(desc))
3671 return dev_err_probe(dev, PTR_ERR(desc), "Cannot get rs485-term-gpios\n");
3672 port->rs485_term_gpio = desc;
3673 if (port->rs485_term_gpio)
3674 port->rs485_supported.flags |= SER_RS485_TERMINATE_BUS;
3675
3676 dflags = (rs485conf->flags & SER_RS485_RX_DURING_TX) ?
3677 GPIOD_OUT_HIGH : GPIOD_OUT_LOW;
3678 desc = devm_gpiod_get_optional(dev, "rs485-rx-during-tx", dflags);
3679 if (IS_ERR(desc))
3680 return dev_err_probe(dev, PTR_ERR(desc), "Cannot get rs485-rx-during-tx-gpios\n");
3681 port->rs485_rx_during_tx_gpio = desc;
3682 if (port->rs485_rx_during_tx_gpio)
3683 port->rs485_supported.flags |= SER_RS485_RX_DURING_TX;
3684
3685 return 0;
3686}
3687EXPORT_SYMBOL_GPL(uart_get_rs485_mode);
3688
3689/* Compile-time assertions for serial_rs485 layout */
3690static_assert(offsetof(struct serial_rs485, padding) ==
3691 (offsetof(struct serial_rs485, delay_rts_after_send) + sizeof(__u32)));
3692static_assert(offsetof(struct serial_rs485, padding1) ==
3693 offsetof(struct serial_rs485, padding[1]));
3694static_assert((offsetof(struct serial_rs485, padding[4]) + sizeof(__u32)) ==
3695 sizeof(struct serial_rs485));
3696
3697MODULE_DESCRIPTION("Serial driver core");
3698MODULE_LICENSE("GPL");