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