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 */
40 static DEFINE_MUTEX(port_mutex);
41
42 /*
43 * lockdep: port->lock is initialized in two places, but we
44 * want only one lock-class:
45 */
46 static 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
55 static void uart_change_pm(struct uart_state *state,
56 enum uart_pm_state pm_state);
57
58 static void uart_port_shutdown(struct tty_port *port);
59
uart_dcd_enabled(struct uart_port * uport)60 static int uart_dcd_enabled(struct uart_port *uport)
61 {
62 return !!(uport->status & UPSTAT_DCD_ENABLE);
63 }
64
uart_port_ref(struct uart_state * state)65 static 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
uart_port_deref(struct uart_port * uport)72 static 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 spin_lock_irqsave(&__uport->lock, flags); \
83 __uport; \
84 })
85
86 #define uart_port_unlock(uport, flags) \
87 ({ \
88 struct uart_port *__uport = uport; \
89 if (__uport) { \
90 spin_unlock_irqrestore(&__uport->lock, flags); \
91 uart_port_deref(__uport); \
92 } \
93 })
94
uart_port_check(struct uart_state * state)95 static 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 */
uart_write_wakeup(struct uart_port * port)112 void 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 }
122 EXPORT_SYMBOL(uart_write_wakeup);
123
uart_stop(struct tty_struct * tty)124 static 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
__uart_start(struct uart_state * state)136 static 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))
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
uart_start(struct tty_struct * tty)165 static 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
176 static void
uart_update_mctrl(struct uart_port * port,unsigned int set,unsigned int clear)177 uart_update_mctrl(struct uart_port *port, unsigned int set, unsigned int clear)
178 {
179 unsigned long flags;
180 unsigned int old;
181
182 spin_lock_irqsave(&port->lock, 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 spin_unlock_irqrestore(&port->lock, 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
uart_port_dtr_rts(struct uart_port * uport,bool active)193 static 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 */
uart_change_line_settings(struct tty_struct * tty,struct uart_state * state,const struct ktermios * old_termios)202 static 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 spin_lock_irq(&uport->lock);
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 spin_unlock_irq(&uport->lock);
244 }
245
246 /*
247 * Startup the port. This will be called once per open. All calls
248 * will be serialised by the per-port mutex.
249 */
uart_port_startup(struct tty_struct * tty,struct uart_state * state,bool init_hw)250 static int uart_port_startup(struct tty_struct *tty, struct uart_state *state,
251 bool init_hw)
252 {
253 struct uart_port *uport = uart_port_check(state);
254 unsigned long flags;
255 unsigned long page;
256 int retval = 0;
257
258 if (uport->type == PORT_UNKNOWN)
259 return 1;
260
261 /*
262 * Make sure the device is in D0 state.
263 */
264 uart_change_pm(state, UART_PM_STATE_ON);
265
266 /*
267 * Initialise and allocate the transmit and temporary
268 * buffer.
269 */
270 page = get_zeroed_page(GFP_KERNEL);
271 if (!page)
272 return -ENOMEM;
273
274 uart_port_lock(state, flags);
275 if (!state->xmit.buf) {
276 state->xmit.buf = (unsigned char *) page;
277 uart_circ_clear(&state->xmit);
278 uart_port_unlock(uport, flags);
279 } else {
280 uart_port_unlock(uport, flags);
281 /*
282 * Do not free() the page under the port lock, see
283 * uart_shutdown().
284 */
285 free_page(page);
286 }
287
288 retval = uport->ops->startup(uport);
289 if (retval == 0) {
290 if (uart_console(uport) && uport->cons->cflag) {
291 tty->termios.c_cflag = uport->cons->cflag;
292 tty->termios.c_ispeed = uport->cons->ispeed;
293 tty->termios.c_ospeed = uport->cons->ospeed;
294 uport->cons->cflag = 0;
295 uport->cons->ispeed = 0;
296 uport->cons->ospeed = 0;
297 }
298 /*
299 * Initialise the hardware port settings.
300 */
301 uart_change_line_settings(tty, state, NULL);
302
303 /*
304 * Setup the RTS and DTR signals once the
305 * port is open and ready to respond.
306 */
307 if (init_hw && C_BAUD(tty))
308 uart_port_dtr_rts(uport, true);
309 }
310
311 /*
312 * This is to allow setserial on this port. People may want to set
313 * port/irq/type and then reconfigure the port properly if it failed
314 * now.
315 */
316 if (retval && capable(CAP_SYS_ADMIN))
317 return 1;
318
319 return retval;
320 }
321
uart_startup(struct tty_struct * tty,struct uart_state * state,bool init_hw)322 static int uart_startup(struct tty_struct *tty, struct uart_state *state,
323 bool init_hw)
324 {
325 struct tty_port *port = &state->port;
326 struct uart_port *uport;
327 int retval;
328
329 if (tty_port_initialized(port))
330 goto out_base_port_startup;
331
332 retval = uart_port_startup(tty, state, init_hw);
333 if (retval) {
334 set_bit(TTY_IO_ERROR, &tty->flags);
335 return retval;
336 }
337
338 out_base_port_startup:
339 uport = uart_port_check(state);
340 if (!uport)
341 return -EIO;
342
343 serial_base_port_startup(uport);
344
345 return 0;
346 }
347
348 /*
349 * This routine will shutdown a serial port; interrupts are disabled, and
350 * DTR is dropped if the hangup on close termio flag is on. Calls to
351 * uart_shutdown are serialised by the per-port semaphore.
352 *
353 * uport == NULL if uart_port has already been removed
354 */
uart_shutdown(struct tty_struct * tty,struct uart_state * state)355 static void uart_shutdown(struct tty_struct *tty, struct uart_state *state)
356 {
357 struct uart_port *uport = uart_port_check(state);
358 struct tty_port *port = &state->port;
359 unsigned long flags;
360 char *xmit_buf = NULL;
361
362 /*
363 * Set the TTY IO error marker
364 */
365 if (tty)
366 set_bit(TTY_IO_ERROR, &tty->flags);
367
368 if (uport)
369 serial_base_port_shutdown(uport);
370
371 if (tty_port_initialized(port)) {
372 tty_port_set_initialized(port, false);
373
374 /*
375 * Turn off DTR and RTS early.
376 */
377 if (uport && uart_console(uport) && tty) {
378 uport->cons->cflag = tty->termios.c_cflag;
379 uport->cons->ispeed = tty->termios.c_ispeed;
380 uport->cons->ospeed = tty->termios.c_ospeed;
381 }
382
383 if (!tty || C_HUPCL(tty))
384 uart_port_dtr_rts(uport, false);
385
386 uart_port_shutdown(port);
387 }
388
389 /*
390 * It's possible for shutdown to be called after suspend if we get
391 * a DCD drop (hangup) at just the right time. Clear suspended bit so
392 * we don't try to resume a port that has been shutdown.
393 */
394 tty_port_set_suspended(port, false);
395
396 /*
397 * Do not free() the transmit buffer page under the port lock since
398 * this can create various circular locking scenarios. For instance,
399 * console driver may need to allocate/free a debug object, which
400 * can endup in printk() recursion.
401 */
402 uart_port_lock(state, flags);
403 xmit_buf = state->xmit.buf;
404 state->xmit.buf = NULL;
405 uart_port_unlock(uport, flags);
406
407 free_page((unsigned long)xmit_buf);
408 }
409
410 /**
411 * uart_update_timeout - update per-port frame timing information
412 * @port: uart_port structure describing the port
413 * @cflag: termios cflag value
414 * @baud: speed of the port
415 *
416 * Set the @port frame timing information from which the FIFO timeout value is
417 * derived. The @cflag value should reflect the actual hardware settings as
418 * number of bits, parity, stop bits and baud rate is taken into account here.
419 *
420 * Locking: caller is expected to take @port->lock
421 */
422 void
uart_update_timeout(struct uart_port * port,unsigned int cflag,unsigned int baud)423 uart_update_timeout(struct uart_port *port, unsigned int cflag,
424 unsigned int baud)
425 {
426 unsigned int size = tty_get_frame_size(cflag);
427 u64 frame_time;
428
429 frame_time = (u64)size * NSEC_PER_SEC;
430 port->frame_time = DIV64_U64_ROUND_UP(frame_time, baud);
431 }
432 EXPORT_SYMBOL(uart_update_timeout);
433
434 /**
435 * uart_get_baud_rate - return baud rate for a particular port
436 * @port: uart_port structure describing the port in question.
437 * @termios: desired termios settings
438 * @old: old termios (or %NULL)
439 * @min: minimum acceptable baud rate
440 * @max: maximum acceptable baud rate
441 *
442 * Decode the termios structure into a numeric baud rate, taking account of the
443 * magic 38400 baud rate (with spd_* flags), and mapping the %B0 rate to 9600
444 * baud.
445 *
446 * If the new baud rate is invalid, try the @old termios setting. If it's still
447 * invalid, we try 9600 baud.
448 *
449 * The @termios structure is updated to reflect the baud rate we're actually
450 * going to be using. Don't do this for the case where B0 is requested ("hang
451 * up").
452 *
453 * Locking: caller dependent
454 */
455 unsigned int
uart_get_baud_rate(struct uart_port * port,struct ktermios * termios,const struct ktermios * old,unsigned int min,unsigned int max)456 uart_get_baud_rate(struct uart_port *port, struct ktermios *termios,
457 const struct ktermios *old, unsigned int min, unsigned int max)
458 {
459 unsigned int try;
460 unsigned int baud;
461 unsigned int altbaud;
462 int hung_up = 0;
463 upf_t flags = port->flags & UPF_SPD_MASK;
464
465 switch (flags) {
466 case UPF_SPD_HI:
467 altbaud = 57600;
468 break;
469 case UPF_SPD_VHI:
470 altbaud = 115200;
471 break;
472 case UPF_SPD_SHI:
473 altbaud = 230400;
474 break;
475 case UPF_SPD_WARP:
476 altbaud = 460800;
477 break;
478 default:
479 altbaud = 38400;
480 break;
481 }
482
483 for (try = 0; try < 2; try++) {
484 baud = tty_termios_baud_rate(termios);
485
486 /*
487 * The spd_hi, spd_vhi, spd_shi, spd_warp kludge...
488 * Die! Die! Die!
489 */
490 if (try == 0 && baud == 38400)
491 baud = altbaud;
492
493 /*
494 * Special case: B0 rate.
495 */
496 if (baud == 0) {
497 hung_up = 1;
498 baud = 9600;
499 }
500
501 if (baud >= min && baud <= max)
502 return baud;
503
504 /*
505 * Oops, the quotient was zero. Try again with
506 * the old baud rate if possible.
507 */
508 termios->c_cflag &= ~CBAUD;
509 if (old) {
510 baud = tty_termios_baud_rate(old);
511 if (!hung_up)
512 tty_termios_encode_baud_rate(termios,
513 baud, baud);
514 old = NULL;
515 continue;
516 }
517
518 /*
519 * As a last resort, if the range cannot be met then clip to
520 * the nearest chip supported rate.
521 */
522 if (!hung_up) {
523 if (baud <= min)
524 tty_termios_encode_baud_rate(termios,
525 min + 1, min + 1);
526 else
527 tty_termios_encode_baud_rate(termios,
528 max - 1, max - 1);
529 }
530 }
531 /* Should never happen */
532 WARN_ON(1);
533 return 0;
534 }
535 EXPORT_SYMBOL(uart_get_baud_rate);
536
537 /**
538 * uart_get_divisor - return uart clock divisor
539 * @port: uart_port structure describing the port
540 * @baud: desired baud rate
541 *
542 * Calculate the divisor (baud_base / baud) for the specified @baud,
543 * appropriately rounded.
544 *
545 * If 38400 baud and custom divisor is selected, return the custom divisor
546 * instead.
547 *
548 * Locking: caller dependent
549 */
550 unsigned int
uart_get_divisor(struct uart_port * port,unsigned int baud)551 uart_get_divisor(struct uart_port *port, unsigned int baud)
552 {
553 unsigned int quot;
554
555 /*
556 * Old custom speed handling.
557 */
558 if (baud == 38400 && (port->flags & UPF_SPD_MASK) == UPF_SPD_CUST)
559 quot = port->custom_divisor;
560 else
561 quot = DIV_ROUND_CLOSEST(port->uartclk, 16 * baud);
562
563 return quot;
564 }
565 EXPORT_SYMBOL(uart_get_divisor);
566
uart_put_char(struct tty_struct * tty,u8 c)567 static int uart_put_char(struct tty_struct *tty, u8 c)
568 {
569 struct uart_state *state = tty->driver_data;
570 struct uart_port *port;
571 struct circ_buf *circ;
572 unsigned long flags;
573 int ret = 0;
574
575 circ = &state->xmit;
576 port = uart_port_lock(state, flags);
577 if (!circ->buf) {
578 uart_port_unlock(port, flags);
579 return 0;
580 }
581
582 if (port && uart_circ_chars_free(circ) != 0) {
583 circ->buf[circ->head] = c;
584 circ->head = (circ->head + 1) & (UART_XMIT_SIZE - 1);
585 ret = 1;
586 }
587 uart_port_unlock(port, flags);
588 return ret;
589 }
590
uart_flush_chars(struct tty_struct * tty)591 static void uart_flush_chars(struct tty_struct *tty)
592 {
593 uart_start(tty);
594 }
595
uart_write(struct tty_struct * tty,const u8 * buf,size_t count)596 static ssize_t uart_write(struct tty_struct *tty, const u8 *buf, size_t count)
597 {
598 struct uart_state *state = tty->driver_data;
599 struct uart_port *port;
600 struct circ_buf *circ;
601 unsigned long flags;
602 int c, ret = 0;
603
604 /*
605 * This means you called this function _after_ the port was
606 * closed. No cookie for you.
607 */
608 if (WARN_ON(!state))
609 return -EL3HLT;
610
611 port = uart_port_lock(state, flags);
612 circ = &state->xmit;
613 if (!circ->buf) {
614 uart_port_unlock(port, flags);
615 return 0;
616 }
617
618 while (port) {
619 c = CIRC_SPACE_TO_END(circ->head, circ->tail, UART_XMIT_SIZE);
620 if (count < c)
621 c = count;
622 if (c <= 0)
623 break;
624 memcpy(circ->buf + circ->head, buf, c);
625 circ->head = (circ->head + c) & (UART_XMIT_SIZE - 1);
626 buf += c;
627 count -= c;
628 ret += c;
629 }
630
631 __uart_start(state);
632 uart_port_unlock(port, flags);
633 return ret;
634 }
635
uart_write_room(struct tty_struct * tty)636 static unsigned int uart_write_room(struct tty_struct *tty)
637 {
638 struct uart_state *state = tty->driver_data;
639 struct uart_port *port;
640 unsigned long flags;
641 unsigned int ret;
642
643 port = uart_port_lock(state, flags);
644 ret = uart_circ_chars_free(&state->xmit);
645 uart_port_unlock(port, flags);
646 return ret;
647 }
648
uart_chars_in_buffer(struct tty_struct * tty)649 static unsigned int uart_chars_in_buffer(struct tty_struct *tty)
650 {
651 struct uart_state *state = tty->driver_data;
652 struct uart_port *port;
653 unsigned long flags;
654 unsigned int ret;
655
656 port = uart_port_lock(state, flags);
657 ret = uart_circ_chars_pending(&state->xmit);
658 uart_port_unlock(port, flags);
659 return ret;
660 }
661
uart_flush_buffer(struct tty_struct * tty)662 static void uart_flush_buffer(struct tty_struct *tty)
663 {
664 struct uart_state *state = tty->driver_data;
665 struct uart_port *port;
666 unsigned long flags;
667
668 /*
669 * This means you called this function _after_ the port was
670 * closed. No cookie for you.
671 */
672 if (WARN_ON(!state))
673 return;
674
675 pr_debug("uart_flush_buffer(%d) called\n", tty->index);
676
677 port = uart_port_lock(state, flags);
678 if (!port)
679 return;
680 uart_circ_clear(&state->xmit);
681 if (port->ops->flush_buffer)
682 port->ops->flush_buffer(port);
683 uart_port_unlock(port, flags);
684 tty_port_tty_wakeup(&state->port);
685 }
686
687 /*
688 * This function performs low-level write of high-priority XON/XOFF
689 * character and accounting for it.
690 *
691 * Requires uart_port to implement .serial_out().
692 */
uart_xchar_out(struct uart_port * uport,int offset)693 void uart_xchar_out(struct uart_port *uport, int offset)
694 {
695 serial_port_out(uport, offset, uport->x_char);
696 uport->icount.tx++;
697 uport->x_char = 0;
698 }
699 EXPORT_SYMBOL_GPL(uart_xchar_out);
700
701 /*
702 * This function is used to send a high-priority XON/XOFF character to
703 * the device
704 */
uart_send_xchar(struct tty_struct * tty,char ch)705 static void uart_send_xchar(struct tty_struct *tty, char ch)
706 {
707 struct uart_state *state = tty->driver_data;
708 struct uart_port *port;
709 unsigned long flags;
710
711 port = uart_port_ref(state);
712 if (!port)
713 return;
714
715 if (port->ops->send_xchar)
716 port->ops->send_xchar(port, ch);
717 else {
718 spin_lock_irqsave(&port->lock, flags);
719 port->x_char = ch;
720 if (ch)
721 port->ops->start_tx(port);
722 spin_unlock_irqrestore(&port->lock, flags);
723 }
724 uart_port_deref(port);
725 }
726
uart_throttle(struct tty_struct * tty)727 static void uart_throttle(struct tty_struct *tty)
728 {
729 struct uart_state *state = tty->driver_data;
730 upstat_t mask = UPSTAT_SYNC_FIFO;
731 struct uart_port *port;
732
733 port = uart_port_ref(state);
734 if (!port)
735 return;
736
737 if (I_IXOFF(tty))
738 mask |= UPSTAT_AUTOXOFF;
739 if (C_CRTSCTS(tty))
740 mask |= UPSTAT_AUTORTS;
741
742 if (port->status & mask) {
743 port->ops->throttle(port);
744 mask &= ~port->status;
745 }
746
747 if (mask & UPSTAT_AUTORTS)
748 uart_clear_mctrl(port, TIOCM_RTS);
749
750 if (mask & UPSTAT_AUTOXOFF)
751 uart_send_xchar(tty, STOP_CHAR(tty));
752
753 uart_port_deref(port);
754 }
755
uart_unthrottle(struct tty_struct * tty)756 static void uart_unthrottle(struct tty_struct *tty)
757 {
758 struct uart_state *state = tty->driver_data;
759 upstat_t mask = UPSTAT_SYNC_FIFO;
760 struct uart_port *port;
761
762 port = uart_port_ref(state);
763 if (!port)
764 return;
765
766 if (I_IXOFF(tty))
767 mask |= UPSTAT_AUTOXOFF;
768 if (C_CRTSCTS(tty))
769 mask |= UPSTAT_AUTORTS;
770
771 if (port->status & mask) {
772 port->ops->unthrottle(port);
773 mask &= ~port->status;
774 }
775
776 if (mask & UPSTAT_AUTORTS)
777 uart_set_mctrl(port, TIOCM_RTS);
778
779 if (mask & UPSTAT_AUTOXOFF)
780 uart_send_xchar(tty, START_CHAR(tty));
781
782 uart_port_deref(port);
783 }
784
uart_get_info(struct tty_port * port,struct serial_struct * retinfo)785 static int uart_get_info(struct tty_port *port, struct serial_struct *retinfo)
786 {
787 struct uart_state *state = container_of(port, struct uart_state, port);
788 struct uart_port *uport;
789 int ret = -ENODEV;
790
791 /*
792 * Ensure the state we copy is consistent and no hardware changes
793 * occur as we go
794 */
795 mutex_lock(&port->mutex);
796 uport = uart_port_check(state);
797 if (!uport)
798 goto out;
799
800 retinfo->type = uport->type;
801 retinfo->line = uport->line;
802 retinfo->port = uport->iobase;
803 if (HIGH_BITS_OFFSET)
804 retinfo->port_high = (long) uport->iobase >> HIGH_BITS_OFFSET;
805 retinfo->irq = uport->irq;
806 retinfo->flags = (__force int)uport->flags;
807 retinfo->xmit_fifo_size = uport->fifosize;
808 retinfo->baud_base = uport->uartclk / 16;
809 retinfo->close_delay = jiffies_to_msecs(port->close_delay) / 10;
810 retinfo->closing_wait = port->closing_wait == ASYNC_CLOSING_WAIT_NONE ?
811 ASYNC_CLOSING_WAIT_NONE :
812 jiffies_to_msecs(port->closing_wait) / 10;
813 retinfo->custom_divisor = uport->custom_divisor;
814 retinfo->hub6 = uport->hub6;
815 retinfo->io_type = uport->iotype;
816 retinfo->iomem_reg_shift = uport->regshift;
817 retinfo->iomem_base = (void *)(unsigned long)uport->mapbase;
818
819 ret = 0;
820 out:
821 mutex_unlock(&port->mutex);
822 return ret;
823 }
824
uart_get_info_user(struct tty_struct * tty,struct serial_struct * ss)825 static int uart_get_info_user(struct tty_struct *tty,
826 struct serial_struct *ss)
827 {
828 struct uart_state *state = tty->driver_data;
829 struct tty_port *port = &state->port;
830
831 return uart_get_info(port, ss) < 0 ? -EIO : 0;
832 }
833
uart_set_info(struct tty_struct * tty,struct tty_port * port,struct uart_state * state,struct serial_struct * new_info)834 static int uart_set_info(struct tty_struct *tty, struct tty_port *port,
835 struct uart_state *state,
836 struct serial_struct *new_info)
837 {
838 struct uart_port *uport = uart_port_check(state);
839 unsigned long new_port;
840 unsigned int change_irq, change_port, closing_wait;
841 unsigned int old_custom_divisor, close_delay;
842 upf_t old_flags, new_flags;
843 int retval = 0;
844
845 if (!uport)
846 return -EIO;
847
848 new_port = new_info->port;
849 if (HIGH_BITS_OFFSET)
850 new_port += (unsigned long) new_info->port_high << HIGH_BITS_OFFSET;
851
852 new_info->irq = irq_canonicalize(new_info->irq);
853 close_delay = msecs_to_jiffies(new_info->close_delay * 10);
854 closing_wait = new_info->closing_wait == ASYNC_CLOSING_WAIT_NONE ?
855 ASYNC_CLOSING_WAIT_NONE :
856 msecs_to_jiffies(new_info->closing_wait * 10);
857
858
859 change_irq = !(uport->flags & UPF_FIXED_PORT)
860 && new_info->irq != uport->irq;
861
862 /*
863 * Since changing the 'type' of the port changes its resource
864 * allocations, we should treat type changes the same as
865 * IO port changes.
866 */
867 change_port = !(uport->flags & UPF_FIXED_PORT)
868 && (new_port != uport->iobase ||
869 (unsigned long)new_info->iomem_base != uport->mapbase ||
870 new_info->hub6 != uport->hub6 ||
871 new_info->io_type != uport->iotype ||
872 new_info->iomem_reg_shift != uport->regshift ||
873 new_info->type != uport->type);
874
875 old_flags = uport->flags;
876 new_flags = (__force upf_t)new_info->flags;
877 old_custom_divisor = uport->custom_divisor;
878
879 if (!(uport->flags & UPF_FIXED_PORT)) {
880 unsigned int uartclk = new_info->baud_base * 16;
881 /* check needs to be done here before other settings made */
882 if (uartclk == 0) {
883 retval = -EINVAL;
884 goto exit;
885 }
886 }
887 if (!capable(CAP_SYS_ADMIN)) {
888 retval = -EPERM;
889 if (change_irq || change_port ||
890 (new_info->baud_base != uport->uartclk / 16) ||
891 (close_delay != port->close_delay) ||
892 (closing_wait != port->closing_wait) ||
893 (new_info->xmit_fifo_size &&
894 new_info->xmit_fifo_size != uport->fifosize) ||
895 (((new_flags ^ old_flags) & ~UPF_USR_MASK) != 0))
896 goto exit;
897 uport->flags = ((uport->flags & ~UPF_USR_MASK) |
898 (new_flags & UPF_USR_MASK));
899 uport->custom_divisor = new_info->custom_divisor;
900 goto check_and_exit;
901 }
902
903 if (change_irq || change_port) {
904 retval = security_locked_down(LOCKDOWN_TIOCSSERIAL);
905 if (retval)
906 goto exit;
907 }
908
909 /*
910 * Ask the low level driver to verify the settings.
911 */
912 if (uport->ops->verify_port)
913 retval = uport->ops->verify_port(uport, new_info);
914
915 if ((new_info->irq >= nr_irqs) || (new_info->irq < 0) ||
916 (new_info->baud_base < 9600))
917 retval = -EINVAL;
918
919 if (retval)
920 goto exit;
921
922 if (change_port || change_irq) {
923 retval = -EBUSY;
924
925 /*
926 * Make sure that we are the sole user of this port.
927 */
928 if (tty_port_users(port) > 1)
929 goto exit;
930
931 /*
932 * We need to shutdown the serial port at the old
933 * port/type/irq combination.
934 */
935 uart_shutdown(tty, state);
936 }
937
938 if (change_port) {
939 unsigned long old_iobase, old_mapbase;
940 unsigned int old_type, old_iotype, old_hub6, old_shift;
941
942 old_iobase = uport->iobase;
943 old_mapbase = uport->mapbase;
944 old_type = uport->type;
945 old_hub6 = uport->hub6;
946 old_iotype = uport->iotype;
947 old_shift = uport->regshift;
948
949 /*
950 * Free and release old regions
951 */
952 if (old_type != PORT_UNKNOWN && uport->ops->release_port)
953 uport->ops->release_port(uport);
954
955 uport->iobase = new_port;
956 uport->type = new_info->type;
957 uport->hub6 = new_info->hub6;
958 uport->iotype = new_info->io_type;
959 uport->regshift = new_info->iomem_reg_shift;
960 uport->mapbase = (unsigned long)new_info->iomem_base;
961
962 /*
963 * Claim and map the new regions
964 */
965 if (uport->type != PORT_UNKNOWN && uport->ops->request_port) {
966 retval = uport->ops->request_port(uport);
967 } else {
968 /* Always success - Jean II */
969 retval = 0;
970 }
971
972 /*
973 * If we fail to request resources for the
974 * new port, try to restore the old settings.
975 */
976 if (retval) {
977 uport->iobase = old_iobase;
978 uport->type = old_type;
979 uport->hub6 = old_hub6;
980 uport->iotype = old_iotype;
981 uport->regshift = old_shift;
982 uport->mapbase = old_mapbase;
983
984 if (old_type != PORT_UNKNOWN) {
985 retval = uport->ops->request_port(uport);
986 /*
987 * If we failed to restore the old settings,
988 * we fail like this.
989 */
990 if (retval)
991 uport->type = PORT_UNKNOWN;
992
993 /*
994 * We failed anyway.
995 */
996 retval = -EBUSY;
997 }
998
999 /* Added to return the correct error -Ram Gupta */
1000 goto exit;
1001 }
1002 }
1003
1004 if (change_irq)
1005 uport->irq = new_info->irq;
1006 if (!(uport->flags & UPF_FIXED_PORT))
1007 uport->uartclk = new_info->baud_base * 16;
1008 uport->flags = (uport->flags & ~UPF_CHANGE_MASK) |
1009 (new_flags & UPF_CHANGE_MASK);
1010 uport->custom_divisor = new_info->custom_divisor;
1011 port->close_delay = close_delay;
1012 port->closing_wait = closing_wait;
1013 if (new_info->xmit_fifo_size)
1014 uport->fifosize = new_info->xmit_fifo_size;
1015
1016 check_and_exit:
1017 retval = 0;
1018 if (uport->type == PORT_UNKNOWN)
1019 goto exit;
1020 if (tty_port_initialized(port)) {
1021 if (((old_flags ^ uport->flags) & UPF_SPD_MASK) ||
1022 old_custom_divisor != uport->custom_divisor) {
1023 /*
1024 * If they're setting up a custom divisor or speed,
1025 * instead of clearing it, then bitch about it.
1026 */
1027 if (uport->flags & UPF_SPD_MASK) {
1028 dev_notice_ratelimited(uport->dev,
1029 "%s sets custom speed on %s. This is deprecated.\n",
1030 current->comm,
1031 tty_name(port->tty));
1032 }
1033 uart_change_line_settings(tty, state, NULL);
1034 }
1035 } else {
1036 retval = uart_startup(tty, state, true);
1037 if (retval == 0)
1038 tty_port_set_initialized(port, true);
1039 if (retval > 0)
1040 retval = 0;
1041 }
1042 exit:
1043 return retval;
1044 }
1045
uart_set_info_user(struct tty_struct * tty,struct serial_struct * ss)1046 static int uart_set_info_user(struct tty_struct *tty, struct serial_struct *ss)
1047 {
1048 struct uart_state *state = tty->driver_data;
1049 struct tty_port *port = &state->port;
1050 int retval;
1051
1052 down_write(&tty->termios_rwsem);
1053 /*
1054 * This semaphore protects port->count. It is also
1055 * very useful to prevent opens. Also, take the
1056 * port configuration semaphore to make sure that a
1057 * module insertion/removal doesn't change anything
1058 * under us.
1059 */
1060 mutex_lock(&port->mutex);
1061 retval = uart_set_info(tty, port, state, ss);
1062 mutex_unlock(&port->mutex);
1063 up_write(&tty->termios_rwsem);
1064 return retval;
1065 }
1066
1067 /**
1068 * uart_get_lsr_info - get line status register info
1069 * @tty: tty associated with the UART
1070 * @state: UART being queried
1071 * @value: returned modem value
1072 */
uart_get_lsr_info(struct tty_struct * tty,struct uart_state * state,unsigned int __user * value)1073 static int uart_get_lsr_info(struct tty_struct *tty,
1074 struct uart_state *state, unsigned int __user *value)
1075 {
1076 struct uart_port *uport = uart_port_check(state);
1077 unsigned int result;
1078
1079 result = uport->ops->tx_empty(uport);
1080
1081 /*
1082 * If we're about to load something into the transmit
1083 * register, we'll pretend the transmitter isn't empty to
1084 * avoid a race condition (depending on when the transmit
1085 * interrupt happens).
1086 */
1087 if (uport->x_char ||
1088 ((uart_circ_chars_pending(&state->xmit) > 0) &&
1089 !uart_tx_stopped(uport)))
1090 result &= ~TIOCSER_TEMT;
1091
1092 return put_user(result, value);
1093 }
1094
uart_tiocmget(struct tty_struct * tty)1095 static int uart_tiocmget(struct tty_struct *tty)
1096 {
1097 struct uart_state *state = tty->driver_data;
1098 struct tty_port *port = &state->port;
1099 struct uart_port *uport;
1100 int result = -EIO;
1101
1102 mutex_lock(&port->mutex);
1103 uport = uart_port_check(state);
1104 if (!uport)
1105 goto out;
1106
1107 if (!tty_io_error(tty)) {
1108 result = uport->mctrl;
1109 spin_lock_irq(&uport->lock);
1110 result |= uport->ops->get_mctrl(uport);
1111 spin_unlock_irq(&uport->lock);
1112 }
1113 out:
1114 mutex_unlock(&port->mutex);
1115 return result;
1116 }
1117
1118 static int
uart_tiocmset(struct tty_struct * tty,unsigned int set,unsigned int clear)1119 uart_tiocmset(struct tty_struct *tty, unsigned int set, unsigned int clear)
1120 {
1121 struct uart_state *state = tty->driver_data;
1122 struct tty_port *port = &state->port;
1123 struct uart_port *uport;
1124 int ret = -EIO;
1125
1126 mutex_lock(&port->mutex);
1127 uport = uart_port_check(state);
1128 if (!uport)
1129 goto out;
1130
1131 if (!tty_io_error(tty)) {
1132 uart_update_mctrl(uport, set, clear);
1133 ret = 0;
1134 }
1135 out:
1136 mutex_unlock(&port->mutex);
1137 return ret;
1138 }
1139
uart_break_ctl(struct tty_struct * tty,int break_state)1140 static int uart_break_ctl(struct tty_struct *tty, int break_state)
1141 {
1142 struct uart_state *state = tty->driver_data;
1143 struct tty_port *port = &state->port;
1144 struct uart_port *uport;
1145 int ret = -EIO;
1146
1147 mutex_lock(&port->mutex);
1148 uport = uart_port_check(state);
1149 if (!uport)
1150 goto out;
1151
1152 if (uport->type != PORT_UNKNOWN && uport->ops->break_ctl)
1153 uport->ops->break_ctl(uport, break_state);
1154 ret = 0;
1155 out:
1156 mutex_unlock(&port->mutex);
1157 return ret;
1158 }
1159
uart_do_autoconfig(struct tty_struct * tty,struct uart_state * state)1160 static int uart_do_autoconfig(struct tty_struct *tty, struct uart_state *state)
1161 {
1162 struct tty_port *port = &state->port;
1163 struct uart_port *uport;
1164 int flags, ret;
1165
1166 if (!capable(CAP_SYS_ADMIN))
1167 return -EPERM;
1168
1169 /*
1170 * Take the per-port semaphore. This prevents count from
1171 * changing, and hence any extra opens of the port while
1172 * we're auto-configuring.
1173 */
1174 if (mutex_lock_interruptible(&port->mutex))
1175 return -ERESTARTSYS;
1176
1177 uport = uart_port_check(state);
1178 if (!uport) {
1179 ret = -EIO;
1180 goto out;
1181 }
1182
1183 ret = -EBUSY;
1184 if (tty_port_users(port) == 1) {
1185 uart_shutdown(tty, state);
1186
1187 /*
1188 * If we already have a port type configured,
1189 * we must release its resources.
1190 */
1191 if (uport->type != PORT_UNKNOWN && uport->ops->release_port)
1192 uport->ops->release_port(uport);
1193
1194 flags = UART_CONFIG_TYPE;
1195 if (uport->flags & UPF_AUTO_IRQ)
1196 flags |= UART_CONFIG_IRQ;
1197
1198 /*
1199 * This will claim the ports resources if
1200 * a port is found.
1201 */
1202 uport->ops->config_port(uport, flags);
1203
1204 ret = uart_startup(tty, state, true);
1205 if (ret == 0)
1206 tty_port_set_initialized(port, true);
1207 if (ret > 0)
1208 ret = 0;
1209 }
1210 out:
1211 mutex_unlock(&port->mutex);
1212 return ret;
1213 }
1214
uart_enable_ms(struct uart_port * uport)1215 static void uart_enable_ms(struct uart_port *uport)
1216 {
1217 /*
1218 * Force modem status interrupts on
1219 */
1220 if (uport->ops->enable_ms)
1221 uport->ops->enable_ms(uport);
1222 }
1223
1224 /*
1225 * Wait for any of the 4 modem inputs (DCD,RI,DSR,CTS) to change
1226 * - mask passed in arg for lines of interest
1227 * (use |'ed TIOCM_RNG/DSR/CD/CTS for masking)
1228 * Caller should use TIOCGICOUNT to see which one it was
1229 *
1230 * FIXME: This wants extracting into a common all driver implementation
1231 * of TIOCMWAIT using tty_port.
1232 */
uart_wait_modem_status(struct uart_state * state,unsigned long arg)1233 static int uart_wait_modem_status(struct uart_state *state, unsigned long arg)
1234 {
1235 struct uart_port *uport;
1236 struct tty_port *port = &state->port;
1237 DECLARE_WAITQUEUE(wait, current);
1238 struct uart_icount cprev, cnow;
1239 int ret;
1240
1241 /*
1242 * note the counters on entry
1243 */
1244 uport = uart_port_ref(state);
1245 if (!uport)
1246 return -EIO;
1247 spin_lock_irq(&uport->lock);
1248 memcpy(&cprev, &uport->icount, sizeof(struct uart_icount));
1249 uart_enable_ms(uport);
1250 spin_unlock_irq(&uport->lock);
1251
1252 add_wait_queue(&port->delta_msr_wait, &wait);
1253 for (;;) {
1254 spin_lock_irq(&uport->lock);
1255 memcpy(&cnow, &uport->icount, sizeof(struct uart_icount));
1256 spin_unlock_irq(&uport->lock);
1257
1258 set_current_state(TASK_INTERRUPTIBLE);
1259
1260 if (((arg & TIOCM_RNG) && (cnow.rng != cprev.rng)) ||
1261 ((arg & TIOCM_DSR) && (cnow.dsr != cprev.dsr)) ||
1262 ((arg & TIOCM_CD) && (cnow.dcd != cprev.dcd)) ||
1263 ((arg & TIOCM_CTS) && (cnow.cts != cprev.cts))) {
1264 ret = 0;
1265 break;
1266 }
1267
1268 schedule();
1269
1270 /* see if a signal did it */
1271 if (signal_pending(current)) {
1272 ret = -ERESTARTSYS;
1273 break;
1274 }
1275
1276 cprev = cnow;
1277 }
1278 __set_current_state(TASK_RUNNING);
1279 remove_wait_queue(&port->delta_msr_wait, &wait);
1280 uart_port_deref(uport);
1281
1282 return ret;
1283 }
1284
1285 /*
1286 * Get counter of input serial line interrupts (DCD,RI,DSR,CTS)
1287 * Return: write counters to the user passed counter struct
1288 * NB: both 1->0 and 0->1 transitions are counted except for
1289 * RI where only 0->1 is counted.
1290 */
uart_get_icount(struct tty_struct * tty,struct serial_icounter_struct * icount)1291 static int uart_get_icount(struct tty_struct *tty,
1292 struct serial_icounter_struct *icount)
1293 {
1294 struct uart_state *state = tty->driver_data;
1295 struct uart_icount cnow;
1296 struct uart_port *uport;
1297
1298 uport = uart_port_ref(state);
1299 if (!uport)
1300 return -EIO;
1301 spin_lock_irq(&uport->lock);
1302 memcpy(&cnow, &uport->icount, sizeof(struct uart_icount));
1303 spin_unlock_irq(&uport->lock);
1304 uart_port_deref(uport);
1305
1306 icount->cts = cnow.cts;
1307 icount->dsr = cnow.dsr;
1308 icount->rng = cnow.rng;
1309 icount->dcd = cnow.dcd;
1310 icount->rx = cnow.rx;
1311 icount->tx = cnow.tx;
1312 icount->frame = cnow.frame;
1313 icount->overrun = cnow.overrun;
1314 icount->parity = cnow.parity;
1315 icount->brk = cnow.brk;
1316 icount->buf_overrun = cnow.buf_overrun;
1317
1318 return 0;
1319 }
1320
1321 #define SER_RS485_LEGACY_FLAGS (SER_RS485_ENABLED | SER_RS485_RTS_ON_SEND | \
1322 SER_RS485_RTS_AFTER_SEND | SER_RS485_RX_DURING_TX | \
1323 SER_RS485_TERMINATE_BUS)
1324
uart_check_rs485_flags(struct uart_port * port,struct serial_rs485 * rs485)1325 static int uart_check_rs485_flags(struct uart_port *port, struct serial_rs485 *rs485)
1326 {
1327 u32 flags = rs485->flags;
1328
1329 /* Don't return -EINVAL for unsupported legacy flags */
1330 flags &= ~SER_RS485_LEGACY_FLAGS;
1331
1332 /*
1333 * For any bit outside of the legacy ones that is not supported by
1334 * the driver, return -EINVAL.
1335 */
1336 if (flags & ~port->rs485_supported.flags)
1337 return -EINVAL;
1338
1339 /* Asking for address w/o addressing mode? */
1340 if (!(rs485->flags & SER_RS485_ADDRB) &&
1341 (rs485->flags & (SER_RS485_ADDR_RECV|SER_RS485_ADDR_DEST)))
1342 return -EINVAL;
1343
1344 /* Address given but not enabled? */
1345 if (!(rs485->flags & SER_RS485_ADDR_RECV) && rs485->addr_recv)
1346 return -EINVAL;
1347 if (!(rs485->flags & SER_RS485_ADDR_DEST) && rs485->addr_dest)
1348 return -EINVAL;
1349
1350 return 0;
1351 }
1352
uart_sanitize_serial_rs485_delays(struct uart_port * port,struct serial_rs485 * rs485)1353 static void uart_sanitize_serial_rs485_delays(struct uart_port *port,
1354 struct serial_rs485 *rs485)
1355 {
1356 if (!port->rs485_supported.delay_rts_before_send) {
1357 if (rs485->delay_rts_before_send) {
1358 dev_warn_ratelimited(port->dev,
1359 "%s (%d): RTS delay before sending not supported\n",
1360 port->name, port->line);
1361 }
1362 rs485->delay_rts_before_send = 0;
1363 } else if (rs485->delay_rts_before_send > RS485_MAX_RTS_DELAY) {
1364 rs485->delay_rts_before_send = RS485_MAX_RTS_DELAY;
1365 dev_warn_ratelimited(port->dev,
1366 "%s (%d): RTS delay before sending clamped to %u ms\n",
1367 port->name, port->line, rs485->delay_rts_before_send);
1368 }
1369
1370 if (!port->rs485_supported.delay_rts_after_send) {
1371 if (rs485->delay_rts_after_send) {
1372 dev_warn_ratelimited(port->dev,
1373 "%s (%d): RTS delay after sending not supported\n",
1374 port->name, port->line);
1375 }
1376 rs485->delay_rts_after_send = 0;
1377 } else if (rs485->delay_rts_after_send > RS485_MAX_RTS_DELAY) {
1378 rs485->delay_rts_after_send = RS485_MAX_RTS_DELAY;
1379 dev_warn_ratelimited(port->dev,
1380 "%s (%d): RTS delay after sending clamped to %u ms\n",
1381 port->name, port->line, rs485->delay_rts_after_send);
1382 }
1383 }
1384
uart_sanitize_serial_rs485(struct uart_port * port,struct serial_rs485 * rs485)1385 static void uart_sanitize_serial_rs485(struct uart_port *port, struct serial_rs485 *rs485)
1386 {
1387 u32 supported_flags = port->rs485_supported.flags;
1388
1389 if (!(rs485->flags & SER_RS485_ENABLED)) {
1390 memset(rs485, 0, sizeof(*rs485));
1391 return;
1392 }
1393
1394 rs485->flags &= supported_flags;
1395
1396 /* Pick sane settings if the user hasn't */
1397 if (!(rs485->flags & SER_RS485_RTS_ON_SEND) ==
1398 !(rs485->flags & SER_RS485_RTS_AFTER_SEND)) {
1399 if (supported_flags & SER_RS485_RTS_ON_SEND) {
1400 rs485->flags |= SER_RS485_RTS_ON_SEND;
1401 rs485->flags &= ~SER_RS485_RTS_AFTER_SEND;
1402
1403 dev_warn_ratelimited(port->dev,
1404 "%s (%d): invalid RTS setting, using RTS_ON_SEND instead\n",
1405 port->name, port->line);
1406 } else {
1407 rs485->flags |= SER_RS485_RTS_AFTER_SEND;
1408 rs485->flags &= ~SER_RS485_RTS_ON_SEND;
1409
1410 dev_warn_ratelimited(port->dev,
1411 "%s (%d): invalid RTS setting, using RTS_AFTER_SEND instead\n",
1412 port->name, port->line);
1413 }
1414 }
1415
1416 uart_sanitize_serial_rs485_delays(port, rs485);
1417
1418 /* Return clean padding area to userspace */
1419 memset(rs485->padding0, 0, sizeof(rs485->padding0));
1420 memset(rs485->padding1, 0, sizeof(rs485->padding1));
1421 }
1422
uart_set_rs485_termination(struct uart_port * port,const struct serial_rs485 * rs485)1423 static void uart_set_rs485_termination(struct uart_port *port,
1424 const struct serial_rs485 *rs485)
1425 {
1426 if (!(rs485->flags & SER_RS485_ENABLED))
1427 return;
1428
1429 gpiod_set_value_cansleep(port->rs485_term_gpio,
1430 !!(rs485->flags & SER_RS485_TERMINATE_BUS));
1431 }
1432
uart_set_rs485_rx_during_tx(struct uart_port * port,const struct serial_rs485 * rs485)1433 static void uart_set_rs485_rx_during_tx(struct uart_port *port,
1434 const struct serial_rs485 *rs485)
1435 {
1436 if (!(rs485->flags & SER_RS485_ENABLED))
1437 return;
1438
1439 gpiod_set_value_cansleep(port->rs485_rx_during_tx_gpio,
1440 !!(rs485->flags & SER_RS485_RX_DURING_TX));
1441 }
1442
uart_rs485_config(struct uart_port * port)1443 static int uart_rs485_config(struct uart_port *port)
1444 {
1445 struct serial_rs485 *rs485 = &port->rs485;
1446 unsigned long flags;
1447 int ret;
1448
1449 if (!(rs485->flags & SER_RS485_ENABLED))
1450 return 0;
1451
1452 uart_sanitize_serial_rs485(port, rs485);
1453 uart_set_rs485_termination(port, rs485);
1454 uart_set_rs485_rx_during_tx(port, rs485);
1455
1456 spin_lock_irqsave(&port->lock, flags);
1457 ret = port->rs485_config(port, NULL, rs485);
1458 spin_unlock_irqrestore(&port->lock, flags);
1459 if (ret) {
1460 memset(rs485, 0, sizeof(*rs485));
1461 /* unset GPIOs */
1462 gpiod_set_value_cansleep(port->rs485_term_gpio, 0);
1463 gpiod_set_value_cansleep(port->rs485_rx_during_tx_gpio, 0);
1464 }
1465
1466 return ret;
1467 }
1468
uart_get_rs485_config(struct uart_port * port,struct serial_rs485 __user * rs485)1469 static int uart_get_rs485_config(struct uart_port *port,
1470 struct serial_rs485 __user *rs485)
1471 {
1472 unsigned long flags;
1473 struct serial_rs485 aux;
1474
1475 spin_lock_irqsave(&port->lock, flags);
1476 aux = port->rs485;
1477 spin_unlock_irqrestore(&port->lock, flags);
1478
1479 if (copy_to_user(rs485, &aux, sizeof(aux)))
1480 return -EFAULT;
1481
1482 return 0;
1483 }
1484
uart_set_rs485_config(struct tty_struct * tty,struct uart_port * port,struct serial_rs485 __user * rs485_user)1485 static int uart_set_rs485_config(struct tty_struct *tty, struct uart_port *port,
1486 struct serial_rs485 __user *rs485_user)
1487 {
1488 struct serial_rs485 rs485;
1489 int ret;
1490 unsigned long flags;
1491
1492 if (!(port->rs485_supported.flags & SER_RS485_ENABLED))
1493 return -ENOTTY;
1494
1495 if (copy_from_user(&rs485, rs485_user, sizeof(*rs485_user)))
1496 return -EFAULT;
1497
1498 ret = uart_check_rs485_flags(port, &rs485);
1499 if (ret)
1500 return ret;
1501 uart_sanitize_serial_rs485(port, &rs485);
1502 uart_set_rs485_termination(port, &rs485);
1503 uart_set_rs485_rx_during_tx(port, &rs485);
1504
1505 spin_lock_irqsave(&port->lock, flags);
1506 ret = port->rs485_config(port, &tty->termios, &rs485);
1507 if (!ret) {
1508 port->rs485 = rs485;
1509
1510 /* Reset RTS and other mctrl lines when disabling RS485 */
1511 if (!(rs485.flags & SER_RS485_ENABLED))
1512 port->ops->set_mctrl(port, port->mctrl);
1513 }
1514 spin_unlock_irqrestore(&port->lock, flags);
1515 if (ret) {
1516 /* restore old GPIO settings */
1517 gpiod_set_value_cansleep(port->rs485_term_gpio,
1518 !!(port->rs485.flags & SER_RS485_TERMINATE_BUS));
1519 gpiod_set_value_cansleep(port->rs485_rx_during_tx_gpio,
1520 !!(port->rs485.flags & SER_RS485_RX_DURING_TX));
1521 return ret;
1522 }
1523
1524 if (copy_to_user(rs485_user, &port->rs485, sizeof(port->rs485)))
1525 return -EFAULT;
1526
1527 return 0;
1528 }
1529
uart_get_iso7816_config(struct uart_port * port,struct serial_iso7816 __user * iso7816)1530 static int uart_get_iso7816_config(struct uart_port *port,
1531 struct serial_iso7816 __user *iso7816)
1532 {
1533 unsigned long flags;
1534 struct serial_iso7816 aux;
1535
1536 if (!port->iso7816_config)
1537 return -ENOTTY;
1538
1539 spin_lock_irqsave(&port->lock, flags);
1540 aux = port->iso7816;
1541 spin_unlock_irqrestore(&port->lock, flags);
1542
1543 if (copy_to_user(iso7816, &aux, sizeof(aux)))
1544 return -EFAULT;
1545
1546 return 0;
1547 }
1548
uart_set_iso7816_config(struct uart_port * port,struct serial_iso7816 __user * iso7816_user)1549 static int uart_set_iso7816_config(struct uart_port *port,
1550 struct serial_iso7816 __user *iso7816_user)
1551 {
1552 struct serial_iso7816 iso7816;
1553 int i, ret;
1554 unsigned long flags;
1555
1556 if (!port->iso7816_config)
1557 return -ENOTTY;
1558
1559 if (copy_from_user(&iso7816, iso7816_user, sizeof(*iso7816_user)))
1560 return -EFAULT;
1561
1562 /*
1563 * There are 5 words reserved for future use. Check that userspace
1564 * doesn't put stuff in there to prevent breakages in the future.
1565 */
1566 for (i = 0; i < ARRAY_SIZE(iso7816.reserved); i++)
1567 if (iso7816.reserved[i])
1568 return -EINVAL;
1569
1570 spin_lock_irqsave(&port->lock, flags);
1571 ret = port->iso7816_config(port, &iso7816);
1572 spin_unlock_irqrestore(&port->lock, flags);
1573 if (ret)
1574 return ret;
1575
1576 if (copy_to_user(iso7816_user, &port->iso7816, sizeof(port->iso7816)))
1577 return -EFAULT;
1578
1579 return 0;
1580 }
1581
1582 /*
1583 * Called via sys_ioctl. We can use spin_lock_irq() here.
1584 */
1585 static int
uart_ioctl(struct tty_struct * tty,unsigned int cmd,unsigned long arg)1586 uart_ioctl(struct tty_struct *tty, unsigned int cmd, unsigned long arg)
1587 {
1588 struct uart_state *state = tty->driver_data;
1589 struct tty_port *port = &state->port;
1590 struct uart_port *uport;
1591 void __user *uarg = (void __user *)arg;
1592 int ret = -ENOIOCTLCMD;
1593
1594
1595 /*
1596 * These ioctls don't rely on the hardware to be present.
1597 */
1598 switch (cmd) {
1599 case TIOCSERCONFIG:
1600 down_write(&tty->termios_rwsem);
1601 ret = uart_do_autoconfig(tty, state);
1602 up_write(&tty->termios_rwsem);
1603 break;
1604 }
1605
1606 if (ret != -ENOIOCTLCMD)
1607 goto out;
1608
1609 if (tty_io_error(tty)) {
1610 ret = -EIO;
1611 goto out;
1612 }
1613
1614 /*
1615 * The following should only be used when hardware is present.
1616 */
1617 switch (cmd) {
1618 case TIOCMIWAIT:
1619 ret = uart_wait_modem_status(state, arg);
1620 break;
1621 }
1622
1623 if (ret != -ENOIOCTLCMD)
1624 goto out;
1625
1626 /* rs485_config requires more locking than others */
1627 if (cmd == TIOCSRS485)
1628 down_write(&tty->termios_rwsem);
1629
1630 mutex_lock(&port->mutex);
1631 uport = uart_port_check(state);
1632
1633 if (!uport || tty_io_error(tty)) {
1634 ret = -EIO;
1635 goto out_up;
1636 }
1637
1638 /*
1639 * All these rely on hardware being present and need to be
1640 * protected against the tty being hung up.
1641 */
1642
1643 switch (cmd) {
1644 case TIOCSERGETLSR: /* Get line status register */
1645 ret = uart_get_lsr_info(tty, state, uarg);
1646 break;
1647
1648 case TIOCGRS485:
1649 ret = uart_get_rs485_config(uport, uarg);
1650 break;
1651
1652 case TIOCSRS485:
1653 ret = uart_set_rs485_config(tty, uport, uarg);
1654 break;
1655
1656 case TIOCSISO7816:
1657 ret = uart_set_iso7816_config(state->uart_port, uarg);
1658 break;
1659
1660 case TIOCGISO7816:
1661 ret = uart_get_iso7816_config(state->uart_port, uarg);
1662 break;
1663 default:
1664 if (uport->ops->ioctl)
1665 ret = uport->ops->ioctl(uport, cmd, arg);
1666 break;
1667 }
1668 out_up:
1669 mutex_unlock(&port->mutex);
1670 if (cmd == TIOCSRS485)
1671 up_write(&tty->termios_rwsem);
1672 out:
1673 return ret;
1674 }
1675
uart_set_ldisc(struct tty_struct * tty)1676 static void uart_set_ldisc(struct tty_struct *tty)
1677 {
1678 struct uart_state *state = tty->driver_data;
1679 struct uart_port *uport;
1680 struct tty_port *port = &state->port;
1681
1682 if (!tty_port_initialized(port))
1683 return;
1684
1685 mutex_lock(&state->port.mutex);
1686 uport = uart_port_check(state);
1687 if (uport && uport->ops->set_ldisc)
1688 uport->ops->set_ldisc(uport, &tty->termios);
1689 mutex_unlock(&state->port.mutex);
1690 }
1691
uart_set_termios(struct tty_struct * tty,const struct ktermios * old_termios)1692 static void uart_set_termios(struct tty_struct *tty,
1693 const struct ktermios *old_termios)
1694 {
1695 struct uart_state *state = tty->driver_data;
1696 struct uart_port *uport;
1697 unsigned int cflag = tty->termios.c_cflag;
1698 unsigned int iflag_mask = IGNBRK|BRKINT|IGNPAR|PARMRK|INPCK;
1699 bool sw_changed = false;
1700
1701 mutex_lock(&state->port.mutex);
1702 uport = uart_port_check(state);
1703 if (!uport)
1704 goto out;
1705
1706 /*
1707 * Drivers doing software flow control also need to know
1708 * about changes to these input settings.
1709 */
1710 if (uport->flags & UPF_SOFT_FLOW) {
1711 iflag_mask |= IXANY|IXON|IXOFF;
1712 sw_changed =
1713 tty->termios.c_cc[VSTART] != old_termios->c_cc[VSTART] ||
1714 tty->termios.c_cc[VSTOP] != old_termios->c_cc[VSTOP];
1715 }
1716
1717 /*
1718 * These are the bits that are used to setup various
1719 * flags in the low level driver. We can ignore the Bfoo
1720 * bits in c_cflag; c_[io]speed will always be set
1721 * appropriately by set_termios() in tty_ioctl.c
1722 */
1723 if ((cflag ^ old_termios->c_cflag) == 0 &&
1724 tty->termios.c_ospeed == old_termios->c_ospeed &&
1725 tty->termios.c_ispeed == old_termios->c_ispeed &&
1726 ((tty->termios.c_iflag ^ old_termios->c_iflag) & iflag_mask) == 0 &&
1727 !sw_changed) {
1728 goto out;
1729 }
1730
1731 uart_change_line_settings(tty, state, old_termios);
1732 /* reload cflag from termios; port driver may have overridden flags */
1733 cflag = tty->termios.c_cflag;
1734
1735 /* Handle transition to B0 status */
1736 if (((old_termios->c_cflag & CBAUD) != B0) && ((cflag & CBAUD) == B0))
1737 uart_clear_mctrl(uport, TIOCM_RTS | TIOCM_DTR);
1738 /* Handle transition away from B0 status */
1739 else if (((old_termios->c_cflag & CBAUD) == B0) && ((cflag & CBAUD) != B0)) {
1740 unsigned int mask = TIOCM_DTR;
1741
1742 if (!(cflag & CRTSCTS) || !tty_throttled(tty))
1743 mask |= TIOCM_RTS;
1744 uart_set_mctrl(uport, mask);
1745 }
1746 out:
1747 mutex_unlock(&state->port.mutex);
1748 }
1749
1750 /*
1751 * Calls to uart_close() are serialised via the tty_lock in
1752 * drivers/tty/tty_io.c:tty_release()
1753 * drivers/tty/tty_io.c:do_tty_hangup()
1754 */
uart_close(struct tty_struct * tty,struct file * filp)1755 static void uart_close(struct tty_struct *tty, struct file *filp)
1756 {
1757 struct uart_state *state = tty->driver_data;
1758
1759 if (!state) {
1760 struct uart_driver *drv = tty->driver->driver_state;
1761 struct tty_port *port;
1762
1763 state = drv->state + tty->index;
1764 port = &state->port;
1765 spin_lock_irq(&port->lock);
1766 --port->count;
1767 spin_unlock_irq(&port->lock);
1768 return;
1769 }
1770
1771 pr_debug("uart_close(%d) called\n", tty->index);
1772
1773 tty_port_close(tty->port, tty, filp);
1774 }
1775
uart_tty_port_shutdown(struct tty_port * port)1776 static void uart_tty_port_shutdown(struct tty_port *port)
1777 {
1778 struct uart_state *state = container_of(port, struct uart_state, port);
1779 struct uart_port *uport = uart_port_check(state);
1780 char *buf;
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 spin_lock_irq(&uport->lock);
1790 uport->ops->stop_rx(uport);
1791 spin_unlock_irq(&uport->lock);
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 /*
1804 * Free the transmit buffer.
1805 */
1806 spin_lock_irq(&uport->lock);
1807 uart_circ_clear(&state->xmit);
1808 buf = state->xmit.buf;
1809 state->xmit.buf = NULL;
1810 spin_unlock_irq(&uport->lock);
1811
1812 free_page((unsigned long)buf);
1813
1814 uart_change_pm(state, UART_PM_STATE_OFF);
1815 }
1816
uart_wait_until_sent(struct tty_struct * tty,int timeout)1817 static void uart_wait_until_sent(struct tty_struct *tty, int timeout)
1818 {
1819 struct uart_state *state = tty->driver_data;
1820 struct uart_port *port;
1821 unsigned long char_time, expire, fifo_timeout;
1822
1823 port = uart_port_ref(state);
1824 if (!port)
1825 return;
1826
1827 if (port->type == PORT_UNKNOWN || port->fifosize == 0) {
1828 uart_port_deref(port);
1829 return;
1830 }
1831
1832 /*
1833 * Set the check interval to be 1/5 of the estimated time to
1834 * send a single character, and make it at least 1. The check
1835 * interval should also be less than the timeout.
1836 *
1837 * Note: we have to use pretty tight timings here to satisfy
1838 * the NIST-PCTS.
1839 */
1840 char_time = max(nsecs_to_jiffies(port->frame_time / 5), 1UL);
1841
1842 if (timeout && timeout < char_time)
1843 char_time = timeout;
1844
1845 if (!uart_cts_enabled(port)) {
1846 /*
1847 * If the transmitter hasn't cleared in twice the approximate
1848 * amount of time to send the entire FIFO, it probably won't
1849 * ever clear. This assumes the UART isn't doing flow
1850 * control, which is currently the case. Hence, if it ever
1851 * takes longer than FIFO timeout, this is probably due to a
1852 * UART bug of some kind. So, we clamp the timeout parameter at
1853 * 2 * FIFO timeout.
1854 */
1855 fifo_timeout = uart_fifo_timeout(port);
1856 if (timeout == 0 || timeout > 2 * fifo_timeout)
1857 timeout = 2 * fifo_timeout;
1858 }
1859
1860 expire = jiffies + timeout;
1861
1862 pr_debug("uart_wait_until_sent(%d), jiffies=%lu, expire=%lu...\n",
1863 port->line, jiffies, expire);
1864
1865 /*
1866 * Check whether the transmitter is empty every 'char_time'.
1867 * 'timeout' / 'expire' give us the maximum amount of time
1868 * we wait.
1869 */
1870 while (!port->ops->tx_empty(port)) {
1871 msleep_interruptible(jiffies_to_msecs(char_time));
1872 if (signal_pending(current))
1873 break;
1874 if (timeout && time_after(jiffies, expire))
1875 break;
1876 }
1877 uart_port_deref(port);
1878 }
1879
1880 /*
1881 * Calls to uart_hangup() are serialised by the tty_lock in
1882 * drivers/tty/tty_io.c:do_tty_hangup()
1883 * This runs from a workqueue and can sleep for a _short_ time only.
1884 */
uart_hangup(struct tty_struct * tty)1885 static void uart_hangup(struct tty_struct *tty)
1886 {
1887 struct uart_state *state = tty->driver_data;
1888 struct tty_port *port = &state->port;
1889 struct uart_port *uport;
1890 unsigned long flags;
1891
1892 pr_debug("uart_hangup(%d)\n", tty->index);
1893
1894 mutex_lock(&port->mutex);
1895 uport = uart_port_check(state);
1896 WARN(!uport, "hangup of detached port!\n");
1897
1898 if (tty_port_active(port)) {
1899 uart_flush_buffer(tty);
1900 uart_shutdown(tty, state);
1901 spin_lock_irqsave(&port->lock, flags);
1902 port->count = 0;
1903 spin_unlock_irqrestore(&port->lock, flags);
1904 tty_port_set_active(port, false);
1905 tty_port_tty_set(port, NULL);
1906 if (uport && !uart_console(uport))
1907 uart_change_pm(state, UART_PM_STATE_OFF);
1908 wake_up_interruptible(&port->open_wait);
1909 wake_up_interruptible(&port->delta_msr_wait);
1910 }
1911 mutex_unlock(&port->mutex);
1912 }
1913
1914 /* uport == NULL if uart_port has already been removed */
uart_port_shutdown(struct tty_port * port)1915 static void uart_port_shutdown(struct tty_port *port)
1916 {
1917 struct uart_state *state = container_of(port, struct uart_state, port);
1918 struct uart_port *uport = uart_port_check(state);
1919
1920 /*
1921 * clear delta_msr_wait queue to avoid mem leaks: we may free
1922 * the irq here so the queue might never be woken up. Note
1923 * that we won't end up waiting on delta_msr_wait again since
1924 * any outstanding file descriptors should be pointing at
1925 * hung_up_tty_fops now.
1926 */
1927 wake_up_interruptible(&port->delta_msr_wait);
1928
1929 if (uport) {
1930 /* Free the IRQ and disable the port. */
1931 uport->ops->shutdown(uport);
1932
1933 /* Ensure that the IRQ handler isn't running on another CPU. */
1934 synchronize_irq(uport->irq);
1935 }
1936 }
1937
uart_carrier_raised(struct tty_port * port)1938 static bool uart_carrier_raised(struct tty_port *port)
1939 {
1940 struct uart_state *state = container_of(port, struct uart_state, port);
1941 struct uart_port *uport;
1942 int mctrl;
1943
1944 uport = uart_port_ref(state);
1945 /*
1946 * Should never observe uport == NULL since checks for hangup should
1947 * abort the tty_port_block_til_ready() loop before checking for carrier
1948 * raised -- but report carrier raised if it does anyway so open will
1949 * continue and not sleep
1950 */
1951 if (WARN_ON(!uport))
1952 return true;
1953 spin_lock_irq(&uport->lock);
1954 uart_enable_ms(uport);
1955 mctrl = uport->ops->get_mctrl(uport);
1956 spin_unlock_irq(&uport->lock);
1957 uart_port_deref(uport);
1958
1959 return mctrl & TIOCM_CAR;
1960 }
1961
uart_dtr_rts(struct tty_port * port,bool active)1962 static void uart_dtr_rts(struct tty_port *port, bool active)
1963 {
1964 struct uart_state *state = container_of(port, struct uart_state, port);
1965 struct uart_port *uport;
1966
1967 uport = uart_port_ref(state);
1968 if (!uport)
1969 return;
1970 uart_port_dtr_rts(uport, active);
1971 uart_port_deref(uport);
1972 }
1973
uart_install(struct tty_driver * driver,struct tty_struct * tty)1974 static int uart_install(struct tty_driver *driver, struct tty_struct *tty)
1975 {
1976 struct uart_driver *drv = driver->driver_state;
1977 struct uart_state *state = drv->state + tty->index;
1978
1979 tty->driver_data = state;
1980
1981 return tty_standard_install(driver, tty);
1982 }
1983
1984 /*
1985 * Calls to uart_open are serialised by the tty_lock in
1986 * drivers/tty/tty_io.c:tty_open()
1987 * Note that if this fails, then uart_close() _will_ be called.
1988 *
1989 * In time, we want to scrap the "opening nonpresent ports"
1990 * behaviour and implement an alternative way for setserial
1991 * to set base addresses/ports/types. This will allow us to
1992 * get rid of a certain amount of extra tests.
1993 */
uart_open(struct tty_struct * tty,struct file * filp)1994 static int uart_open(struct tty_struct *tty, struct file *filp)
1995 {
1996 struct uart_state *state = tty->driver_data;
1997 int retval;
1998
1999 retval = tty_port_open(&state->port, tty, filp);
2000 if (retval > 0)
2001 retval = 0;
2002
2003 return retval;
2004 }
2005
uart_port_activate(struct tty_port * port,struct tty_struct * tty)2006 static int uart_port_activate(struct tty_port *port, struct tty_struct *tty)
2007 {
2008 struct uart_state *state = container_of(port, struct uart_state, port);
2009 struct uart_port *uport;
2010 int ret;
2011
2012 uport = uart_port_check(state);
2013 if (!uport || uport->flags & UPF_DEAD)
2014 return -ENXIO;
2015
2016 /*
2017 * Start up the serial port.
2018 */
2019 ret = uart_startup(tty, state, false);
2020 if (ret > 0)
2021 tty_port_set_active(port, true);
2022
2023 return ret;
2024 }
2025
uart_type(struct uart_port * port)2026 static const char *uart_type(struct uart_port *port)
2027 {
2028 const char *str = NULL;
2029
2030 if (port->ops->type)
2031 str = port->ops->type(port);
2032
2033 if (!str)
2034 str = "unknown";
2035
2036 return str;
2037 }
2038
2039 #ifdef CONFIG_PROC_FS
2040
uart_line_info(struct seq_file * m,struct uart_driver * drv,int i)2041 static void uart_line_info(struct seq_file *m, struct uart_driver *drv, int i)
2042 {
2043 struct uart_state *state = drv->state + i;
2044 struct tty_port *port = &state->port;
2045 enum uart_pm_state pm_state;
2046 struct uart_port *uport;
2047 char stat_buf[32];
2048 unsigned int status;
2049 int mmio;
2050
2051 mutex_lock(&port->mutex);
2052 uport = uart_port_check(state);
2053 if (!uport)
2054 goto out;
2055
2056 mmio = uport->iotype >= UPIO_MEM;
2057 seq_printf(m, "%d: uart:%s %s%08llX irq:%d",
2058 uport->line, uart_type(uport),
2059 mmio ? "mmio:0x" : "port:",
2060 mmio ? (unsigned long long)uport->mapbase
2061 : (unsigned long long)uport->iobase,
2062 uport->irq);
2063
2064 if (uport->type == PORT_UNKNOWN) {
2065 seq_putc(m, '\n');
2066 goto out;
2067 }
2068
2069 if (capable(CAP_SYS_ADMIN)) {
2070 pm_state = state->pm_state;
2071 if (pm_state != UART_PM_STATE_ON)
2072 uart_change_pm(state, UART_PM_STATE_ON);
2073 spin_lock_irq(&uport->lock);
2074 status = uport->ops->get_mctrl(uport);
2075 spin_unlock_irq(&uport->lock);
2076 if (pm_state != UART_PM_STATE_ON)
2077 uart_change_pm(state, pm_state);
2078
2079 seq_printf(m, " tx:%d rx:%d",
2080 uport->icount.tx, uport->icount.rx);
2081 if (uport->icount.frame)
2082 seq_printf(m, " fe:%d", uport->icount.frame);
2083 if (uport->icount.parity)
2084 seq_printf(m, " pe:%d", uport->icount.parity);
2085 if (uport->icount.brk)
2086 seq_printf(m, " brk:%d", uport->icount.brk);
2087 if (uport->icount.overrun)
2088 seq_printf(m, " oe:%d", uport->icount.overrun);
2089 if (uport->icount.buf_overrun)
2090 seq_printf(m, " bo:%d", uport->icount.buf_overrun);
2091
2092 #define INFOBIT(bit, str) \
2093 if (uport->mctrl & (bit)) \
2094 strncat(stat_buf, (str), sizeof(stat_buf) - \
2095 strlen(stat_buf) - 2)
2096 #define STATBIT(bit, str) \
2097 if (status & (bit)) \
2098 strncat(stat_buf, (str), sizeof(stat_buf) - \
2099 strlen(stat_buf) - 2)
2100
2101 stat_buf[0] = '\0';
2102 stat_buf[1] = '\0';
2103 INFOBIT(TIOCM_RTS, "|RTS");
2104 STATBIT(TIOCM_CTS, "|CTS");
2105 INFOBIT(TIOCM_DTR, "|DTR");
2106 STATBIT(TIOCM_DSR, "|DSR");
2107 STATBIT(TIOCM_CAR, "|CD");
2108 STATBIT(TIOCM_RNG, "|RI");
2109 if (stat_buf[0])
2110 stat_buf[0] = ' ';
2111
2112 seq_puts(m, stat_buf);
2113 }
2114 seq_putc(m, '\n');
2115 #undef STATBIT
2116 #undef INFOBIT
2117 out:
2118 mutex_unlock(&port->mutex);
2119 }
2120
uart_proc_show(struct seq_file * m,void * v)2121 static int uart_proc_show(struct seq_file *m, void *v)
2122 {
2123 struct tty_driver *ttydrv = m->private;
2124 struct uart_driver *drv = ttydrv->driver_state;
2125 int i;
2126
2127 seq_printf(m, "serinfo:1.0 driver%s%s revision:%s\n", "", "", "");
2128 for (i = 0; i < drv->nr; i++)
2129 uart_line_info(m, drv, i);
2130 return 0;
2131 }
2132 #endif
2133
uart_port_spin_lock_init(struct uart_port * port)2134 static void uart_port_spin_lock_init(struct uart_port *port)
2135 {
2136 spin_lock_init(&port->lock);
2137 lockdep_set_class(&port->lock, &port_lock_key);
2138 }
2139
2140 #if defined(CONFIG_SERIAL_CORE_CONSOLE) || defined(CONFIG_CONSOLE_POLL)
2141 /**
2142 * uart_console_write - write a console message to a serial port
2143 * @port: the port to write the message
2144 * @s: array of characters
2145 * @count: number of characters in string to write
2146 * @putchar: function to write character to port
2147 */
uart_console_write(struct uart_port * port,const char * s,unsigned int count,void (* putchar)(struct uart_port *,unsigned char))2148 void uart_console_write(struct uart_port *port, const char *s,
2149 unsigned int count,
2150 void (*putchar)(struct uart_port *, unsigned char))
2151 {
2152 unsigned int i;
2153
2154 for (i = 0; i < count; i++, s++) {
2155 if (*s == '\n')
2156 putchar(port, '\r');
2157 putchar(port, *s);
2158 }
2159 }
2160 EXPORT_SYMBOL_GPL(uart_console_write);
2161
2162 /**
2163 * uart_get_console - get uart port for console
2164 * @ports: ports to search in
2165 * @nr: number of @ports
2166 * @co: console to search for
2167 * Returns: uart_port for the console @co
2168 *
2169 * Check whether an invalid uart number has been specified (as @co->index), and
2170 * if so, search for the first available port that does have console support.
2171 */
2172 struct uart_port * __init
uart_get_console(struct uart_port * ports,int nr,struct console * co)2173 uart_get_console(struct uart_port *ports, int nr, struct console *co)
2174 {
2175 int idx = co->index;
2176
2177 if (idx < 0 || idx >= nr || (ports[idx].iobase == 0 &&
2178 ports[idx].membase == NULL))
2179 for (idx = 0; idx < nr; idx++)
2180 if (ports[idx].iobase != 0 ||
2181 ports[idx].membase != NULL)
2182 break;
2183
2184 co->index = idx;
2185
2186 return ports + idx;
2187 }
2188
2189 /**
2190 * uart_parse_earlycon - Parse earlycon options
2191 * @p: ptr to 2nd field (ie., just beyond '<name>,')
2192 * @iotype: ptr for decoded iotype (out)
2193 * @addr: ptr for decoded mapbase/iobase (out)
2194 * @options: ptr for <options> field; %NULL if not present (out)
2195 *
2196 * Decodes earlycon kernel command line parameters of the form:
2197 * * earlycon=<name>,io|mmio|mmio16|mmio32|mmio32be|mmio32native,<addr>,<options>
2198 * * console=<name>,io|mmio|mmio16|mmio32|mmio32be|mmio32native,<addr>,<options>
2199 *
2200 * The optional form:
2201 * * earlycon=<name>,0x<addr>,<options>
2202 * * console=<name>,0x<addr>,<options>
2203 *
2204 * is also accepted; the returned @iotype will be %UPIO_MEM.
2205 *
2206 * Returns: 0 on success or -%EINVAL on failure
2207 */
uart_parse_earlycon(char * p,unsigned char * iotype,resource_size_t * addr,char ** options)2208 int uart_parse_earlycon(char *p, unsigned char *iotype, resource_size_t *addr,
2209 char **options)
2210 {
2211 if (strncmp(p, "mmio,", 5) == 0) {
2212 *iotype = UPIO_MEM;
2213 p += 5;
2214 } else if (strncmp(p, "mmio16,", 7) == 0) {
2215 *iotype = UPIO_MEM16;
2216 p += 7;
2217 } else if (strncmp(p, "mmio32,", 7) == 0) {
2218 *iotype = UPIO_MEM32;
2219 p += 7;
2220 } else if (strncmp(p, "mmio32be,", 9) == 0) {
2221 *iotype = UPIO_MEM32BE;
2222 p += 9;
2223 } else if (strncmp(p, "mmio32native,", 13) == 0) {
2224 *iotype = IS_ENABLED(CONFIG_CPU_BIG_ENDIAN) ?
2225 UPIO_MEM32BE : UPIO_MEM32;
2226 p += 13;
2227 } else if (strncmp(p, "io,", 3) == 0) {
2228 *iotype = UPIO_PORT;
2229 p += 3;
2230 } else if (strncmp(p, "0x", 2) == 0) {
2231 *iotype = UPIO_MEM;
2232 } else {
2233 return -EINVAL;
2234 }
2235
2236 /*
2237 * Before you replace it with kstrtoull(), think about options separator
2238 * (',') it will not tolerate
2239 */
2240 *addr = simple_strtoull(p, NULL, 0);
2241 p = strchr(p, ',');
2242 if (p)
2243 p++;
2244
2245 *options = p;
2246 return 0;
2247 }
2248 EXPORT_SYMBOL_GPL(uart_parse_earlycon);
2249
2250 /**
2251 * uart_parse_options - Parse serial port baud/parity/bits/flow control.
2252 * @options: pointer to option string
2253 * @baud: pointer to an 'int' variable for the baud rate.
2254 * @parity: pointer to an 'int' variable for the parity.
2255 * @bits: pointer to an 'int' variable for the number of data bits.
2256 * @flow: pointer to an 'int' variable for the flow control character.
2257 *
2258 * uart_parse_options() decodes a string containing the serial console
2259 * options. The format of the string is <baud><parity><bits><flow>,
2260 * eg: 115200n8r
2261 */
2262 void
uart_parse_options(const char * options,int * baud,int * parity,int * bits,int * flow)2263 uart_parse_options(const char *options, int *baud, int *parity,
2264 int *bits, int *flow)
2265 {
2266 const char *s = options;
2267
2268 *baud = simple_strtoul(s, NULL, 10);
2269 while (*s >= '0' && *s <= '9')
2270 s++;
2271 if (*s)
2272 *parity = *s++;
2273 if (*s)
2274 *bits = *s++ - '0';
2275 if (*s)
2276 *flow = *s;
2277 }
2278 EXPORT_SYMBOL_GPL(uart_parse_options);
2279
2280 /**
2281 * uart_set_options - setup the serial console parameters
2282 * @port: pointer to the serial ports uart_port structure
2283 * @co: console pointer
2284 * @baud: baud rate
2285 * @parity: parity character - 'n' (none), 'o' (odd), 'e' (even)
2286 * @bits: number of data bits
2287 * @flow: flow control character - 'r' (rts)
2288 *
2289 * Locking: Caller must hold console_list_lock in order to serialize
2290 * early initialization of the serial-console lock.
2291 */
2292 int
uart_set_options(struct uart_port * port,struct console * co,int baud,int parity,int bits,int flow)2293 uart_set_options(struct uart_port *port, struct console *co,
2294 int baud, int parity, int bits, int flow)
2295 {
2296 struct ktermios termios;
2297 static struct ktermios dummy;
2298
2299 /*
2300 * Ensure that the serial-console lock is initialised early.
2301 *
2302 * Note that the console-registered check is needed because
2303 * kgdboc can call uart_set_options() for an already registered
2304 * console via tty_find_polling_driver() and uart_poll_init().
2305 */
2306 if (!uart_console_registered_locked(port) && !port->console_reinit)
2307 uart_port_spin_lock_init(port);
2308
2309 memset(&termios, 0, sizeof(struct ktermios));
2310
2311 termios.c_cflag |= CREAD | HUPCL | CLOCAL;
2312 tty_termios_encode_baud_rate(&termios, baud, baud);
2313
2314 if (bits == 7)
2315 termios.c_cflag |= CS7;
2316 else
2317 termios.c_cflag |= CS8;
2318
2319 switch (parity) {
2320 case 'o': case 'O':
2321 termios.c_cflag |= PARODD;
2322 fallthrough;
2323 case 'e': case 'E':
2324 termios.c_cflag |= PARENB;
2325 break;
2326 }
2327
2328 if (flow == 'r')
2329 termios.c_cflag |= CRTSCTS;
2330
2331 /*
2332 * some uarts on other side don't support no flow control.
2333 * So we set * DTR in host uart to make them happy
2334 */
2335 port->mctrl |= TIOCM_DTR;
2336
2337 port->ops->set_termios(port, &termios, &dummy);
2338 /*
2339 * Allow the setting of the UART parameters with a NULL console
2340 * too:
2341 */
2342 if (co) {
2343 co->cflag = termios.c_cflag;
2344 co->ispeed = termios.c_ispeed;
2345 co->ospeed = termios.c_ospeed;
2346 }
2347
2348 return 0;
2349 }
2350 EXPORT_SYMBOL_GPL(uart_set_options);
2351 #endif /* CONFIG_SERIAL_CORE_CONSOLE */
2352
2353 /**
2354 * uart_change_pm - set power state of the port
2355 *
2356 * @state: port descriptor
2357 * @pm_state: new state
2358 *
2359 * Locking: port->mutex has to be held
2360 */
uart_change_pm(struct uart_state * state,enum uart_pm_state pm_state)2361 static void uart_change_pm(struct uart_state *state,
2362 enum uart_pm_state pm_state)
2363 {
2364 struct uart_port *port = uart_port_check(state);
2365
2366 if (state->pm_state != pm_state) {
2367 if (port && port->ops->pm)
2368 port->ops->pm(port, pm_state, state->pm_state);
2369 state->pm_state = pm_state;
2370 }
2371 }
2372
2373 struct uart_match {
2374 struct uart_port *port;
2375 struct uart_driver *driver;
2376 };
2377
serial_match_port(struct device * dev,void * data)2378 static int serial_match_port(struct device *dev, void *data)
2379 {
2380 struct uart_match *match = data;
2381 struct tty_driver *tty_drv = match->driver->tty_driver;
2382 dev_t devt = MKDEV(tty_drv->major, tty_drv->minor_start) +
2383 match->port->line;
2384
2385 return dev->devt == devt; /* Actually, only one tty per port */
2386 }
2387
uart_suspend_port(struct uart_driver * drv,struct uart_port * uport)2388 int uart_suspend_port(struct uart_driver *drv, struct uart_port *uport)
2389 {
2390 struct uart_state *state = drv->state + uport->line;
2391 struct tty_port *port = &state->port;
2392 struct device *tty_dev;
2393 struct uart_match match = {uport, drv};
2394
2395 mutex_lock(&port->mutex);
2396
2397 tty_dev = device_find_child(uport->dev, &match, serial_match_port);
2398 if (tty_dev && device_may_wakeup(tty_dev)) {
2399 enable_irq_wake(uport->irq);
2400 put_device(tty_dev);
2401 mutex_unlock(&port->mutex);
2402 return 0;
2403 }
2404 put_device(tty_dev);
2405
2406 /*
2407 * Nothing to do if the console is not suspending
2408 * except stop_rx to prevent any asynchronous data
2409 * over RX line. However ensure that we will be
2410 * able to Re-start_rx later.
2411 */
2412 if (!console_suspend_enabled && uart_console(uport)) {
2413 if (uport->ops->start_rx) {
2414 spin_lock_irq(&uport->lock);
2415 uport->ops->stop_rx(uport);
2416 spin_unlock_irq(&uport->lock);
2417 }
2418 goto unlock;
2419 }
2420
2421 uport->suspended = 1;
2422
2423 if (tty_port_initialized(port)) {
2424 const struct uart_ops *ops = uport->ops;
2425 int tries;
2426 unsigned int mctrl;
2427
2428 tty_port_set_suspended(port, true);
2429 tty_port_set_initialized(port, false);
2430
2431 spin_lock_irq(&uport->lock);
2432 ops->stop_tx(uport);
2433 if (!(uport->rs485.flags & SER_RS485_ENABLED))
2434 ops->set_mctrl(uport, 0);
2435 /* save mctrl so it can be restored on resume */
2436 mctrl = uport->mctrl;
2437 uport->mctrl = 0;
2438 ops->stop_rx(uport);
2439 spin_unlock_irq(&uport->lock);
2440
2441 /*
2442 * Wait for the transmitter to empty.
2443 */
2444 for (tries = 3; !ops->tx_empty(uport) && tries; tries--)
2445 msleep(10);
2446 if (!tries)
2447 dev_err(uport->dev, "%s: Unable to drain transmitter\n",
2448 uport->name);
2449
2450 ops->shutdown(uport);
2451 uport->mctrl = mctrl;
2452 }
2453
2454 /*
2455 * Disable the console device before suspending.
2456 */
2457 if (uart_console(uport))
2458 console_stop(uport->cons);
2459
2460 uart_change_pm(state, UART_PM_STATE_OFF);
2461 unlock:
2462 mutex_unlock(&port->mutex);
2463
2464 return 0;
2465 }
2466 EXPORT_SYMBOL(uart_suspend_port);
2467
uart_resume_port(struct uart_driver * drv,struct uart_port * uport)2468 int uart_resume_port(struct uart_driver *drv, struct uart_port *uport)
2469 {
2470 struct uart_state *state = drv->state + uport->line;
2471 struct tty_port *port = &state->port;
2472 struct device *tty_dev;
2473 struct uart_match match = {uport, drv};
2474 struct ktermios termios;
2475
2476 mutex_lock(&port->mutex);
2477
2478 tty_dev = device_find_child(uport->dev, &match, serial_match_port);
2479 if (!uport->suspended && device_may_wakeup(tty_dev)) {
2480 if (irqd_is_wakeup_set(irq_get_irq_data((uport->irq))))
2481 disable_irq_wake(uport->irq);
2482 put_device(tty_dev);
2483 mutex_unlock(&port->mutex);
2484 return 0;
2485 }
2486 put_device(tty_dev);
2487 uport->suspended = 0;
2488
2489 /*
2490 * Re-enable the console device after suspending.
2491 */
2492 if (uart_console(uport)) {
2493 /*
2494 * First try to use the console cflag setting.
2495 */
2496 memset(&termios, 0, sizeof(struct ktermios));
2497 termios.c_cflag = uport->cons->cflag;
2498 termios.c_ispeed = uport->cons->ispeed;
2499 termios.c_ospeed = uport->cons->ospeed;
2500
2501 /*
2502 * If that's unset, use the tty termios setting.
2503 */
2504 if (port->tty && termios.c_cflag == 0)
2505 termios = port->tty->termios;
2506
2507 if (console_suspend_enabled)
2508 uart_change_pm(state, UART_PM_STATE_ON);
2509 uport->ops->set_termios(uport, &termios, NULL);
2510 if (!console_suspend_enabled && uport->ops->start_rx) {
2511 spin_lock_irq(&uport->lock);
2512 uport->ops->start_rx(uport);
2513 spin_unlock_irq(&uport->lock);
2514 }
2515 if (console_suspend_enabled)
2516 console_start(uport->cons);
2517 }
2518
2519 if (tty_port_suspended(port)) {
2520 const struct uart_ops *ops = uport->ops;
2521 int ret;
2522
2523 uart_change_pm(state, UART_PM_STATE_ON);
2524 spin_lock_irq(&uport->lock);
2525 if (!(uport->rs485.flags & SER_RS485_ENABLED))
2526 ops->set_mctrl(uport, 0);
2527 spin_unlock_irq(&uport->lock);
2528 if (console_suspend_enabled || !uart_console(uport)) {
2529 /* Protected by port mutex for now */
2530 struct tty_struct *tty = port->tty;
2531
2532 ret = ops->startup(uport);
2533 if (ret == 0) {
2534 if (tty)
2535 uart_change_line_settings(tty, state, NULL);
2536 uart_rs485_config(uport);
2537 spin_lock_irq(&uport->lock);
2538 if (!(uport->rs485.flags & SER_RS485_ENABLED))
2539 ops->set_mctrl(uport, uport->mctrl);
2540 ops->start_tx(uport);
2541 spin_unlock_irq(&uport->lock);
2542 tty_port_set_initialized(port, true);
2543 } else {
2544 /*
2545 * Failed to resume - maybe hardware went away?
2546 * Clear the "initialized" flag so we won't try
2547 * to call the low level drivers shutdown method.
2548 */
2549 uart_shutdown(tty, state);
2550 }
2551 }
2552
2553 tty_port_set_suspended(port, false);
2554 }
2555
2556 mutex_unlock(&port->mutex);
2557
2558 return 0;
2559 }
2560 EXPORT_SYMBOL(uart_resume_port);
2561
2562 static inline void
uart_report_port(struct uart_driver * drv,struct uart_port * port)2563 uart_report_port(struct uart_driver *drv, struct uart_port *port)
2564 {
2565 char address[64];
2566
2567 switch (port->iotype) {
2568 case UPIO_PORT:
2569 snprintf(address, sizeof(address), "I/O 0x%lx", port->iobase);
2570 break;
2571 case UPIO_HUB6:
2572 snprintf(address, sizeof(address),
2573 "I/O 0x%lx offset 0x%x", port->iobase, port->hub6);
2574 break;
2575 case UPIO_MEM:
2576 case UPIO_MEM16:
2577 case UPIO_MEM32:
2578 case UPIO_MEM32BE:
2579 case UPIO_AU:
2580 case UPIO_TSI:
2581 snprintf(address, sizeof(address),
2582 "MMIO 0x%llx", (unsigned long long)port->mapbase);
2583 break;
2584 default:
2585 strscpy(address, "*unknown*", sizeof(address));
2586 break;
2587 }
2588
2589 pr_info("%s%s%s at %s (irq = %d, base_baud = %d) is a %s\n",
2590 port->dev ? dev_name(port->dev) : "",
2591 port->dev ? ": " : "",
2592 port->name,
2593 address, port->irq, port->uartclk / 16, uart_type(port));
2594
2595 /* The magic multiplier feature is a bit obscure, so report it too. */
2596 if (port->flags & UPF_MAGIC_MULTIPLIER)
2597 pr_info("%s%s%s extra baud rates supported: %d, %d",
2598 port->dev ? dev_name(port->dev) : "",
2599 port->dev ? ": " : "",
2600 port->name,
2601 port->uartclk / 8, port->uartclk / 4);
2602 }
2603
2604 static void
uart_configure_port(struct uart_driver * drv,struct uart_state * state,struct uart_port * port)2605 uart_configure_port(struct uart_driver *drv, struct uart_state *state,
2606 struct uart_port *port)
2607 {
2608 unsigned int flags;
2609
2610 /*
2611 * If there isn't a port here, don't do anything further.
2612 */
2613 if (!port->iobase && !port->mapbase && !port->membase)
2614 return;
2615
2616 /*
2617 * Now do the auto configuration stuff. Note that config_port
2618 * is expected to claim the resources and map the port for us.
2619 */
2620 flags = 0;
2621 if (port->flags & UPF_AUTO_IRQ)
2622 flags |= UART_CONFIG_IRQ;
2623 if (port->flags & UPF_BOOT_AUTOCONF) {
2624 if (!(port->flags & UPF_FIXED_TYPE)) {
2625 port->type = PORT_UNKNOWN;
2626 flags |= UART_CONFIG_TYPE;
2627 }
2628 /* Synchronize with possible boot console. */
2629 if (uart_console(port))
2630 console_lock();
2631 port->ops->config_port(port, flags);
2632 if (uart_console(port))
2633 console_unlock();
2634 }
2635
2636 if (port->type != PORT_UNKNOWN) {
2637 unsigned long flags;
2638
2639 uart_report_port(drv, port);
2640
2641 /* Synchronize with possible boot console. */
2642 if (uart_console(port))
2643 console_lock();
2644
2645 /* Power up port for set_mctrl() */
2646 uart_change_pm(state, UART_PM_STATE_ON);
2647
2648 /*
2649 * Ensure that the modem control lines are de-activated.
2650 * keep the DTR setting that is set in uart_set_options()
2651 * We probably don't need a spinlock around this, but
2652 */
2653 spin_lock_irqsave(&port->lock, flags);
2654 port->mctrl &= TIOCM_DTR;
2655 if (!(port->rs485.flags & SER_RS485_ENABLED))
2656 port->ops->set_mctrl(port, port->mctrl);
2657 spin_unlock_irqrestore(&port->lock, flags);
2658
2659 uart_rs485_config(port);
2660
2661 if (uart_console(port))
2662 console_unlock();
2663
2664 /*
2665 * If this driver supports console, and it hasn't been
2666 * successfully registered yet, try to re-register it.
2667 * It may be that the port was not available.
2668 */
2669 if (port->cons && !console_is_registered(port->cons))
2670 register_console(port->cons);
2671
2672 /*
2673 * Power down all ports by default, except the
2674 * console if we have one.
2675 */
2676 if (!uart_console(port))
2677 uart_change_pm(state, UART_PM_STATE_OFF);
2678 }
2679 }
2680
2681 #ifdef CONFIG_CONSOLE_POLL
2682
uart_poll_init(struct tty_driver * driver,int line,char * options)2683 static int uart_poll_init(struct tty_driver *driver, int line, char *options)
2684 {
2685 struct uart_driver *drv = driver->driver_state;
2686 struct uart_state *state = drv->state + line;
2687 enum uart_pm_state pm_state;
2688 struct tty_port *tport;
2689 struct uart_port *port;
2690 int baud = 9600;
2691 int bits = 8;
2692 int parity = 'n';
2693 int flow = 'n';
2694 int ret = 0;
2695
2696 tport = &state->port;
2697 mutex_lock(&tport->mutex);
2698
2699 port = uart_port_check(state);
2700 if (!port || !(port->ops->poll_get_char && port->ops->poll_put_char)) {
2701 ret = -1;
2702 goto out;
2703 }
2704
2705 pm_state = state->pm_state;
2706 uart_change_pm(state, UART_PM_STATE_ON);
2707
2708 if (port->ops->poll_init) {
2709 /*
2710 * We don't set initialized as we only initialized the hw,
2711 * e.g. state->xmit is still uninitialized.
2712 */
2713 if (!tty_port_initialized(tport))
2714 ret = port->ops->poll_init(port);
2715 }
2716
2717 if (!ret && options) {
2718 uart_parse_options(options, &baud, &parity, &bits, &flow);
2719 console_list_lock();
2720 ret = uart_set_options(port, NULL, baud, parity, bits, flow);
2721 console_list_unlock();
2722 }
2723 out:
2724 if (ret)
2725 uart_change_pm(state, pm_state);
2726 mutex_unlock(&tport->mutex);
2727 return ret;
2728 }
2729
uart_poll_get_char(struct tty_driver * driver,int line)2730 static int uart_poll_get_char(struct tty_driver *driver, int line)
2731 {
2732 struct uart_driver *drv = driver->driver_state;
2733 struct uart_state *state = drv->state + line;
2734 struct uart_port *port;
2735 int ret = -1;
2736
2737 port = uart_port_ref(state);
2738 if (port) {
2739 ret = port->ops->poll_get_char(port);
2740 uart_port_deref(port);
2741 }
2742
2743 return ret;
2744 }
2745
uart_poll_put_char(struct tty_driver * driver,int line,char ch)2746 static void uart_poll_put_char(struct tty_driver *driver, int line, char ch)
2747 {
2748 struct uart_driver *drv = driver->driver_state;
2749 struct uart_state *state = drv->state + line;
2750 struct uart_port *port;
2751
2752 port = uart_port_ref(state);
2753 if (!port)
2754 return;
2755
2756 if (ch == '\n')
2757 port->ops->poll_put_char(port, '\r');
2758 port->ops->poll_put_char(port, ch);
2759 uart_port_deref(port);
2760 }
2761 #endif
2762
2763 static const struct tty_operations uart_ops = {
2764 .install = uart_install,
2765 .open = uart_open,
2766 .close = uart_close,
2767 .write = uart_write,
2768 .put_char = uart_put_char,
2769 .flush_chars = uart_flush_chars,
2770 .write_room = uart_write_room,
2771 .chars_in_buffer= uart_chars_in_buffer,
2772 .flush_buffer = uart_flush_buffer,
2773 .ioctl = uart_ioctl,
2774 .throttle = uart_throttle,
2775 .unthrottle = uart_unthrottle,
2776 .send_xchar = uart_send_xchar,
2777 .set_termios = uart_set_termios,
2778 .set_ldisc = uart_set_ldisc,
2779 .stop = uart_stop,
2780 .start = uart_start,
2781 .hangup = uart_hangup,
2782 .break_ctl = uart_break_ctl,
2783 .wait_until_sent= uart_wait_until_sent,
2784 #ifdef CONFIG_PROC_FS
2785 .proc_show = uart_proc_show,
2786 #endif
2787 .tiocmget = uart_tiocmget,
2788 .tiocmset = uart_tiocmset,
2789 .set_serial = uart_set_info_user,
2790 .get_serial = uart_get_info_user,
2791 .get_icount = uart_get_icount,
2792 #ifdef CONFIG_CONSOLE_POLL
2793 .poll_init = uart_poll_init,
2794 .poll_get_char = uart_poll_get_char,
2795 .poll_put_char = uart_poll_put_char,
2796 #endif
2797 };
2798
2799 static const struct tty_port_operations uart_port_ops = {
2800 .carrier_raised = uart_carrier_raised,
2801 .dtr_rts = uart_dtr_rts,
2802 .activate = uart_port_activate,
2803 .shutdown = uart_tty_port_shutdown,
2804 };
2805
2806 /**
2807 * uart_register_driver - register a driver with the uart core layer
2808 * @drv: low level driver structure
2809 *
2810 * Register a uart driver with the core driver. We in turn register with the
2811 * tty layer, and initialise the core driver per-port state.
2812 *
2813 * We have a proc file in /proc/tty/driver which is named after the normal
2814 * driver.
2815 *
2816 * @drv->port should be %NULL, and the per-port structures should be registered
2817 * using uart_add_one_port() after this call has succeeded.
2818 *
2819 * Locking: none, Interrupts: enabled
2820 */
uart_register_driver(struct uart_driver * drv)2821 int uart_register_driver(struct uart_driver *drv)
2822 {
2823 struct tty_driver *normal;
2824 int i, retval = -ENOMEM;
2825
2826 BUG_ON(drv->state);
2827
2828 /*
2829 * Maybe we should be using a slab cache for this, especially if
2830 * we have a large number of ports to handle.
2831 */
2832 drv->state = kcalloc(drv->nr, sizeof(struct uart_state), GFP_KERNEL);
2833 if (!drv->state)
2834 goto out;
2835
2836 normal = tty_alloc_driver(drv->nr, TTY_DRIVER_REAL_RAW |
2837 TTY_DRIVER_DYNAMIC_DEV);
2838 if (IS_ERR(normal)) {
2839 retval = PTR_ERR(normal);
2840 goto out_kfree;
2841 }
2842
2843 drv->tty_driver = normal;
2844
2845 normal->driver_name = drv->driver_name;
2846 normal->name = drv->dev_name;
2847 normal->major = drv->major;
2848 normal->minor_start = drv->minor;
2849 normal->type = TTY_DRIVER_TYPE_SERIAL;
2850 normal->subtype = SERIAL_TYPE_NORMAL;
2851 normal->init_termios = tty_std_termios;
2852 normal->init_termios.c_cflag = B9600 | CS8 | CREAD | HUPCL | CLOCAL;
2853 normal->init_termios.c_ispeed = normal->init_termios.c_ospeed = 9600;
2854 normal->driver_state = drv;
2855 tty_set_operations(normal, &uart_ops);
2856
2857 /*
2858 * Initialise the UART state(s).
2859 */
2860 for (i = 0; i < drv->nr; i++) {
2861 struct uart_state *state = drv->state + i;
2862 struct tty_port *port = &state->port;
2863
2864 tty_port_init(port);
2865 port->ops = &uart_port_ops;
2866 }
2867
2868 retval = tty_register_driver(normal);
2869 if (retval >= 0)
2870 return retval;
2871
2872 for (i = 0; i < drv->nr; i++)
2873 tty_port_destroy(&drv->state[i].port);
2874 tty_driver_kref_put(normal);
2875 out_kfree:
2876 kfree(drv->state);
2877 out:
2878 return retval;
2879 }
2880 EXPORT_SYMBOL(uart_register_driver);
2881
2882 /**
2883 * uart_unregister_driver - remove a driver from the uart core layer
2884 * @drv: low level driver structure
2885 *
2886 * Remove all references to a driver from the core driver. The low level
2887 * driver must have removed all its ports via the uart_remove_one_port() if it
2888 * registered them with uart_add_one_port(). (I.e. @drv->port is %NULL.)
2889 *
2890 * Locking: none, Interrupts: enabled
2891 */
uart_unregister_driver(struct uart_driver * drv)2892 void uart_unregister_driver(struct uart_driver *drv)
2893 {
2894 struct tty_driver *p = drv->tty_driver;
2895 unsigned int i;
2896
2897 tty_unregister_driver(p);
2898 tty_driver_kref_put(p);
2899 for (i = 0; i < drv->nr; i++)
2900 tty_port_destroy(&drv->state[i].port);
2901 kfree(drv->state);
2902 drv->state = NULL;
2903 drv->tty_driver = NULL;
2904 }
2905 EXPORT_SYMBOL(uart_unregister_driver);
2906
uart_console_device(struct console * co,int * index)2907 struct tty_driver *uart_console_device(struct console *co, int *index)
2908 {
2909 struct uart_driver *p = co->data;
2910 *index = co->index;
2911 return p->tty_driver;
2912 }
2913 EXPORT_SYMBOL_GPL(uart_console_device);
2914
uartclk_show(struct device * dev,struct device_attribute * attr,char * buf)2915 static ssize_t uartclk_show(struct device *dev,
2916 struct device_attribute *attr, char *buf)
2917 {
2918 struct serial_struct tmp;
2919 struct tty_port *port = dev_get_drvdata(dev);
2920
2921 uart_get_info(port, &tmp);
2922 return sprintf(buf, "%d\n", tmp.baud_base * 16);
2923 }
2924
type_show(struct device * dev,struct device_attribute * attr,char * buf)2925 static ssize_t type_show(struct device *dev,
2926 struct device_attribute *attr, char *buf)
2927 {
2928 struct serial_struct tmp;
2929 struct tty_port *port = dev_get_drvdata(dev);
2930
2931 uart_get_info(port, &tmp);
2932 return sprintf(buf, "%d\n", tmp.type);
2933 }
2934
line_show(struct device * dev,struct device_attribute * attr,char * buf)2935 static ssize_t line_show(struct device *dev,
2936 struct device_attribute *attr, char *buf)
2937 {
2938 struct serial_struct tmp;
2939 struct tty_port *port = dev_get_drvdata(dev);
2940
2941 uart_get_info(port, &tmp);
2942 return sprintf(buf, "%d\n", tmp.line);
2943 }
2944
port_show(struct device * dev,struct device_attribute * attr,char * buf)2945 static ssize_t port_show(struct device *dev,
2946 struct device_attribute *attr, char *buf)
2947 {
2948 struct serial_struct tmp;
2949 struct tty_port *port = dev_get_drvdata(dev);
2950 unsigned long ioaddr;
2951
2952 uart_get_info(port, &tmp);
2953 ioaddr = tmp.port;
2954 if (HIGH_BITS_OFFSET)
2955 ioaddr |= (unsigned long)tmp.port_high << HIGH_BITS_OFFSET;
2956 return sprintf(buf, "0x%lX\n", ioaddr);
2957 }
2958
irq_show(struct device * dev,struct device_attribute * attr,char * buf)2959 static ssize_t irq_show(struct device *dev,
2960 struct device_attribute *attr, char *buf)
2961 {
2962 struct serial_struct tmp;
2963 struct tty_port *port = dev_get_drvdata(dev);
2964
2965 uart_get_info(port, &tmp);
2966 return sprintf(buf, "%d\n", tmp.irq);
2967 }
2968
flags_show(struct device * dev,struct device_attribute * attr,char * buf)2969 static ssize_t flags_show(struct device *dev,
2970 struct device_attribute *attr, char *buf)
2971 {
2972 struct serial_struct tmp;
2973 struct tty_port *port = dev_get_drvdata(dev);
2974
2975 uart_get_info(port, &tmp);
2976 return sprintf(buf, "0x%X\n", tmp.flags);
2977 }
2978
xmit_fifo_size_show(struct device * dev,struct device_attribute * attr,char * buf)2979 static ssize_t xmit_fifo_size_show(struct device *dev,
2980 struct device_attribute *attr, char *buf)
2981 {
2982 struct serial_struct tmp;
2983 struct tty_port *port = dev_get_drvdata(dev);
2984
2985 uart_get_info(port, &tmp);
2986 return sprintf(buf, "%d\n", tmp.xmit_fifo_size);
2987 }
2988
close_delay_show(struct device * dev,struct device_attribute * attr,char * buf)2989 static ssize_t close_delay_show(struct device *dev,
2990 struct device_attribute *attr, char *buf)
2991 {
2992 struct serial_struct tmp;
2993 struct tty_port *port = dev_get_drvdata(dev);
2994
2995 uart_get_info(port, &tmp);
2996 return sprintf(buf, "%d\n", tmp.close_delay);
2997 }
2998
closing_wait_show(struct device * dev,struct device_attribute * attr,char * buf)2999 static ssize_t closing_wait_show(struct device *dev,
3000 struct device_attribute *attr, char *buf)
3001 {
3002 struct serial_struct tmp;
3003 struct tty_port *port = dev_get_drvdata(dev);
3004
3005 uart_get_info(port, &tmp);
3006 return sprintf(buf, "%d\n", tmp.closing_wait);
3007 }
3008
custom_divisor_show(struct device * dev,struct device_attribute * attr,char * buf)3009 static ssize_t custom_divisor_show(struct device *dev,
3010 struct device_attribute *attr, char *buf)
3011 {
3012 struct serial_struct tmp;
3013 struct tty_port *port = dev_get_drvdata(dev);
3014
3015 uart_get_info(port, &tmp);
3016 return sprintf(buf, "%d\n", tmp.custom_divisor);
3017 }
3018
io_type_show(struct device * dev,struct device_attribute * attr,char * buf)3019 static ssize_t io_type_show(struct device *dev,
3020 struct device_attribute *attr, char *buf)
3021 {
3022 struct serial_struct tmp;
3023 struct tty_port *port = dev_get_drvdata(dev);
3024
3025 uart_get_info(port, &tmp);
3026 return sprintf(buf, "%d\n", tmp.io_type);
3027 }
3028
iomem_base_show(struct device * dev,struct device_attribute * attr,char * buf)3029 static ssize_t iomem_base_show(struct device *dev,
3030 struct device_attribute *attr, char *buf)
3031 {
3032 struct serial_struct tmp;
3033 struct tty_port *port = dev_get_drvdata(dev);
3034
3035 uart_get_info(port, &tmp);
3036 return sprintf(buf, "0x%lX\n", (unsigned long)tmp.iomem_base);
3037 }
3038
iomem_reg_shift_show(struct device * dev,struct device_attribute * attr,char * buf)3039 static ssize_t iomem_reg_shift_show(struct device *dev,
3040 struct device_attribute *attr, char *buf)
3041 {
3042 struct serial_struct tmp;
3043 struct tty_port *port = dev_get_drvdata(dev);
3044
3045 uart_get_info(port, &tmp);
3046 return sprintf(buf, "%d\n", tmp.iomem_reg_shift);
3047 }
3048
console_show(struct device * dev,struct device_attribute * attr,char * buf)3049 static ssize_t console_show(struct device *dev,
3050 struct device_attribute *attr, char *buf)
3051 {
3052 struct tty_port *port = dev_get_drvdata(dev);
3053 struct uart_state *state = container_of(port, struct uart_state, port);
3054 struct uart_port *uport;
3055 bool console = false;
3056
3057 mutex_lock(&port->mutex);
3058 uport = uart_port_check(state);
3059 if (uport)
3060 console = uart_console_registered(uport);
3061 mutex_unlock(&port->mutex);
3062
3063 return sprintf(buf, "%c\n", console ? 'Y' : 'N');
3064 }
3065
console_store(struct device * dev,struct device_attribute * attr,const char * buf,size_t count)3066 static ssize_t console_store(struct device *dev,
3067 struct device_attribute *attr, const char *buf, size_t count)
3068 {
3069 struct tty_port *port = dev_get_drvdata(dev);
3070 struct uart_state *state = container_of(port, struct uart_state, port);
3071 struct uart_port *uport;
3072 bool oldconsole, newconsole;
3073 int ret;
3074
3075 ret = kstrtobool(buf, &newconsole);
3076 if (ret)
3077 return ret;
3078
3079 mutex_lock(&port->mutex);
3080 uport = uart_port_check(state);
3081 if (uport) {
3082 oldconsole = uart_console_registered(uport);
3083 if (oldconsole && !newconsole) {
3084 ret = unregister_console(uport->cons);
3085 } else if (!oldconsole && newconsole) {
3086 if (uart_console(uport)) {
3087 uport->console_reinit = 1;
3088 register_console(uport->cons);
3089 } else {
3090 ret = -ENOENT;
3091 }
3092 }
3093 } else {
3094 ret = -ENXIO;
3095 }
3096 mutex_unlock(&port->mutex);
3097
3098 return ret < 0 ? ret : count;
3099 }
3100
3101 static DEVICE_ATTR_RO(uartclk);
3102 static DEVICE_ATTR_RO(type);
3103 static DEVICE_ATTR_RO(line);
3104 static DEVICE_ATTR_RO(port);
3105 static DEVICE_ATTR_RO(irq);
3106 static DEVICE_ATTR_RO(flags);
3107 static DEVICE_ATTR_RO(xmit_fifo_size);
3108 static DEVICE_ATTR_RO(close_delay);
3109 static DEVICE_ATTR_RO(closing_wait);
3110 static DEVICE_ATTR_RO(custom_divisor);
3111 static DEVICE_ATTR_RO(io_type);
3112 static DEVICE_ATTR_RO(iomem_base);
3113 static DEVICE_ATTR_RO(iomem_reg_shift);
3114 static DEVICE_ATTR_RW(console);
3115
3116 static struct attribute *tty_dev_attrs[] = {
3117 &dev_attr_uartclk.attr,
3118 &dev_attr_type.attr,
3119 &dev_attr_line.attr,
3120 &dev_attr_port.attr,
3121 &dev_attr_irq.attr,
3122 &dev_attr_flags.attr,
3123 &dev_attr_xmit_fifo_size.attr,
3124 &dev_attr_close_delay.attr,
3125 &dev_attr_closing_wait.attr,
3126 &dev_attr_custom_divisor.attr,
3127 &dev_attr_io_type.attr,
3128 &dev_attr_iomem_base.attr,
3129 &dev_attr_iomem_reg_shift.attr,
3130 &dev_attr_console.attr,
3131 NULL
3132 };
3133
3134 static const struct attribute_group tty_dev_attr_group = {
3135 .attrs = tty_dev_attrs,
3136 };
3137
3138 /**
3139 * serial_core_add_one_port - attach a driver-defined port structure
3140 * @drv: pointer to the uart low level driver structure for this port
3141 * @uport: uart port structure to use for this port.
3142 *
3143 * Context: task context, might sleep
3144 *
3145 * This allows the driver @drv to register its own uart_port structure with the
3146 * core driver. The main purpose is to allow the low level uart drivers to
3147 * expand uart_port, rather than having yet more levels of structures.
3148 * Caller must hold port_mutex.
3149 */
serial_core_add_one_port(struct uart_driver * drv,struct uart_port * uport)3150 static int serial_core_add_one_port(struct uart_driver *drv, struct uart_port *uport)
3151 {
3152 struct uart_state *state;
3153 struct tty_port *port;
3154 int ret = 0;
3155 struct device *tty_dev;
3156 int num_groups;
3157
3158 if (uport->line >= drv->nr)
3159 return -EINVAL;
3160
3161 state = drv->state + uport->line;
3162 port = &state->port;
3163
3164 mutex_lock(&port->mutex);
3165 if (state->uart_port) {
3166 ret = -EINVAL;
3167 goto out;
3168 }
3169
3170 /* Link the port to the driver state table and vice versa */
3171 atomic_set(&state->refcount, 1);
3172 init_waitqueue_head(&state->remove_wait);
3173 state->uart_port = uport;
3174 uport->state = state;
3175
3176 state->pm_state = UART_PM_STATE_UNDEFINED;
3177 uport->cons = drv->cons;
3178 uport->minor = drv->tty_driver->minor_start + uport->line;
3179 uport->name = kasprintf(GFP_KERNEL, "%s%d", drv->dev_name,
3180 drv->tty_driver->name_base + uport->line);
3181 if (!uport->name) {
3182 ret = -ENOMEM;
3183 goto out;
3184 }
3185
3186 /*
3187 * If this port is in use as a console then the spinlock is already
3188 * initialised.
3189 */
3190 if (!uart_console_registered(uport))
3191 uart_port_spin_lock_init(uport);
3192
3193 if (uport->cons && uport->dev)
3194 of_console_check(uport->dev->of_node, uport->cons->name, uport->line);
3195
3196 tty_port_link_device(port, drv->tty_driver, uport->line);
3197 uart_configure_port(drv, state, uport);
3198
3199 port->console = uart_console(uport);
3200
3201 num_groups = 2;
3202 if (uport->attr_group)
3203 num_groups++;
3204
3205 uport->tty_groups = kcalloc(num_groups, sizeof(*uport->tty_groups),
3206 GFP_KERNEL);
3207 if (!uport->tty_groups) {
3208 ret = -ENOMEM;
3209 goto out;
3210 }
3211 uport->tty_groups[0] = &tty_dev_attr_group;
3212 if (uport->attr_group)
3213 uport->tty_groups[1] = uport->attr_group;
3214
3215 /*
3216 * Register the port whether it's detected or not. This allows
3217 * setserial to be used to alter this port's parameters.
3218 */
3219 tty_dev = tty_port_register_device_attr_serdev(port, drv->tty_driver,
3220 uport->line, uport->dev, port, uport->tty_groups);
3221 if (!IS_ERR(tty_dev)) {
3222 device_set_wakeup_capable(tty_dev, 1);
3223 } else {
3224 dev_err(uport->dev, "Cannot register tty device on line %d\n",
3225 uport->line);
3226 }
3227
3228 out:
3229 mutex_unlock(&port->mutex);
3230
3231 return ret;
3232 }
3233
3234 /**
3235 * serial_core_remove_one_port - detach a driver defined port structure
3236 * @drv: pointer to the uart low level driver structure for this port
3237 * @uport: uart port structure for this port
3238 *
3239 * Context: task context, might sleep
3240 *
3241 * This unhooks (and hangs up) the specified port structure from the core
3242 * driver. No further calls will be made to the low-level code for this port.
3243 * Caller must hold port_mutex.
3244 */
serial_core_remove_one_port(struct uart_driver * drv,struct uart_port * uport)3245 static void serial_core_remove_one_port(struct uart_driver *drv,
3246 struct uart_port *uport)
3247 {
3248 struct uart_state *state = drv->state + uport->line;
3249 struct tty_port *port = &state->port;
3250 struct uart_port *uart_port;
3251 struct tty_struct *tty;
3252
3253 mutex_lock(&port->mutex);
3254 uart_port = uart_port_check(state);
3255 if (uart_port != uport)
3256 dev_alert(uport->dev, "Removing wrong port: %p != %p\n",
3257 uart_port, uport);
3258
3259 if (!uart_port) {
3260 mutex_unlock(&port->mutex);
3261 return;
3262 }
3263 mutex_unlock(&port->mutex);
3264
3265 /*
3266 * Remove the devices from the tty layer
3267 */
3268 tty_port_unregister_device(port, drv->tty_driver, uport->line);
3269
3270 tty = tty_port_tty_get(port);
3271 if (tty) {
3272 tty_vhangup(port->tty);
3273 tty_kref_put(tty);
3274 }
3275
3276 /*
3277 * If the port is used as a console, unregister it
3278 */
3279 if (uart_console(uport))
3280 unregister_console(uport->cons);
3281
3282 /*
3283 * Free the port IO and memory resources, if any.
3284 */
3285 if (uport->type != PORT_UNKNOWN && uport->ops->release_port)
3286 uport->ops->release_port(uport);
3287 kfree(uport->tty_groups);
3288 kfree(uport->name);
3289
3290 /*
3291 * Indicate that there isn't a port here anymore.
3292 */
3293 uport->type = PORT_UNKNOWN;
3294 uport->port_dev = NULL;
3295
3296 mutex_lock(&port->mutex);
3297 WARN_ON(atomic_dec_return(&state->refcount) < 0);
3298 wait_event(state->remove_wait, !atomic_read(&state->refcount));
3299 state->uart_port = NULL;
3300 mutex_unlock(&port->mutex);
3301 }
3302
3303 /**
3304 * uart_match_port - are the two ports equivalent?
3305 * @port1: first port
3306 * @port2: second port
3307 *
3308 * This utility function can be used to determine whether two uart_port
3309 * structures describe the same port.
3310 */
uart_match_port(const struct uart_port * port1,const struct uart_port * port2)3311 bool uart_match_port(const struct uart_port *port1,
3312 const struct uart_port *port2)
3313 {
3314 if (port1->iotype != port2->iotype)
3315 return false;
3316
3317 switch (port1->iotype) {
3318 case UPIO_PORT:
3319 return port1->iobase == port2->iobase;
3320 case UPIO_HUB6:
3321 return port1->iobase == port2->iobase &&
3322 port1->hub6 == port2->hub6;
3323 case UPIO_MEM:
3324 case UPIO_MEM16:
3325 case UPIO_MEM32:
3326 case UPIO_MEM32BE:
3327 case UPIO_AU:
3328 case UPIO_TSI:
3329 return port1->mapbase == port2->mapbase;
3330 }
3331
3332 return false;
3333 }
3334 EXPORT_SYMBOL(uart_match_port);
3335
3336 static struct serial_ctrl_device *
serial_core_get_ctrl_dev(struct serial_port_device * port_dev)3337 serial_core_get_ctrl_dev(struct serial_port_device *port_dev)
3338 {
3339 struct device *dev = &port_dev->dev;
3340
3341 return to_serial_base_ctrl_device(dev->parent);
3342 }
3343
3344 /*
3345 * Find a registered serial core controller device if one exists. Returns
3346 * the first device matching the ctrl_id. Caller must hold port_mutex.
3347 */
serial_core_ctrl_find(struct uart_driver * drv,struct device * phys_dev,int ctrl_id)3348 static struct serial_ctrl_device *serial_core_ctrl_find(struct uart_driver *drv,
3349 struct device *phys_dev,
3350 int ctrl_id)
3351 {
3352 struct uart_state *state;
3353 int i;
3354
3355 lockdep_assert_held(&port_mutex);
3356
3357 for (i = 0; i < drv->nr; i++) {
3358 state = drv->state + i;
3359 if (!state->uart_port || !state->uart_port->port_dev)
3360 continue;
3361
3362 if (state->uart_port->dev == phys_dev &&
3363 state->uart_port->ctrl_id == ctrl_id)
3364 return serial_core_get_ctrl_dev(state->uart_port->port_dev);
3365 }
3366
3367 return NULL;
3368 }
3369
serial_core_ctrl_device_add(struct uart_port * port)3370 static struct serial_ctrl_device *serial_core_ctrl_device_add(struct uart_port *port)
3371 {
3372 return serial_base_ctrl_add(port, port->dev);
3373 }
3374
serial_core_port_device_add(struct serial_ctrl_device * ctrl_dev,struct uart_port * port)3375 static int serial_core_port_device_add(struct serial_ctrl_device *ctrl_dev,
3376 struct uart_port *port)
3377 {
3378 struct serial_port_device *port_dev;
3379
3380 port_dev = serial_base_port_add(port, ctrl_dev);
3381 if (IS_ERR(port_dev))
3382 return PTR_ERR(port_dev);
3383
3384 port->port_dev = port_dev;
3385
3386 return 0;
3387 }
3388
3389 /*
3390 * Initialize a serial core port device, and a controller device if needed.
3391 */
serial_core_register_port(struct uart_driver * drv,struct uart_port * port)3392 int serial_core_register_port(struct uart_driver *drv, struct uart_port *port)
3393 {
3394 struct serial_ctrl_device *ctrl_dev, *new_ctrl_dev = NULL;
3395 int ret;
3396
3397 mutex_lock(&port_mutex);
3398
3399 /*
3400 * Prevent serial_port_runtime_resume() from trying to use the port
3401 * until serial_core_add_one_port() has completed
3402 */
3403 port->flags |= UPF_DEAD;
3404
3405 /* Inititalize a serial core controller device if needed */
3406 ctrl_dev = serial_core_ctrl_find(drv, port->dev, port->ctrl_id);
3407 if (!ctrl_dev) {
3408 new_ctrl_dev = serial_core_ctrl_device_add(port);
3409 if (IS_ERR(new_ctrl_dev)) {
3410 ret = PTR_ERR(new_ctrl_dev);
3411 goto err_unlock;
3412 }
3413 ctrl_dev = new_ctrl_dev;
3414 }
3415
3416 /*
3417 * Initialize a serial core port device. Tag the port dead to prevent
3418 * serial_port_runtime_resume() trying to do anything until port has
3419 * been registered. It gets cleared by serial_core_add_one_port().
3420 */
3421 ret = serial_core_port_device_add(ctrl_dev, port);
3422 if (ret)
3423 goto err_unregister_ctrl_dev;
3424
3425 ret = serial_core_add_one_port(drv, port);
3426 if (ret)
3427 goto err_unregister_port_dev;
3428
3429 port->flags &= ~UPF_DEAD;
3430
3431 mutex_unlock(&port_mutex);
3432
3433 return 0;
3434
3435 err_unregister_port_dev:
3436 serial_base_port_device_remove(port->port_dev);
3437
3438 err_unregister_ctrl_dev:
3439 serial_base_ctrl_device_remove(new_ctrl_dev);
3440
3441 err_unlock:
3442 mutex_unlock(&port_mutex);
3443
3444 return ret;
3445 }
3446
3447 /*
3448 * Removes a serial core port device, and the related serial core controller
3449 * device if the last instance.
3450 */
serial_core_unregister_port(struct uart_driver * drv,struct uart_port * port)3451 void serial_core_unregister_port(struct uart_driver *drv, struct uart_port *port)
3452 {
3453 struct device *phys_dev = port->dev;
3454 struct serial_port_device *port_dev = port->port_dev;
3455 struct serial_ctrl_device *ctrl_dev = serial_core_get_ctrl_dev(port_dev);
3456 int ctrl_id = port->ctrl_id;
3457
3458 mutex_lock(&port_mutex);
3459
3460 port->flags |= UPF_DEAD;
3461
3462 serial_core_remove_one_port(drv, port);
3463
3464 /* Note that struct uart_port *port is no longer valid at this point */
3465 serial_base_port_device_remove(port_dev);
3466
3467 /* Drop the serial core controller device if no ports are using it */
3468 if (!serial_core_ctrl_find(drv, phys_dev, ctrl_id))
3469 serial_base_ctrl_device_remove(ctrl_dev);
3470
3471 mutex_unlock(&port_mutex);
3472 }
3473
3474 /**
3475 * uart_handle_dcd_change - handle a change of carrier detect state
3476 * @uport: uart_port structure for the open port
3477 * @active: new carrier detect status
3478 *
3479 * Caller must hold uport->lock.
3480 */
uart_handle_dcd_change(struct uart_port * uport,bool active)3481 void uart_handle_dcd_change(struct uart_port *uport, bool active)
3482 {
3483 struct tty_port *port = &uport->state->port;
3484 struct tty_struct *tty = port->tty;
3485 struct tty_ldisc *ld;
3486
3487 lockdep_assert_held_once(&uport->lock);
3488
3489 if (tty) {
3490 ld = tty_ldisc_ref(tty);
3491 if (ld) {
3492 if (ld->ops->dcd_change)
3493 ld->ops->dcd_change(tty, active);
3494 tty_ldisc_deref(ld);
3495 }
3496 }
3497
3498 uport->icount.dcd++;
3499
3500 if (uart_dcd_enabled(uport)) {
3501 if (active)
3502 wake_up_interruptible(&port->open_wait);
3503 else if (tty)
3504 tty_hangup(tty);
3505 }
3506 }
3507 EXPORT_SYMBOL_GPL(uart_handle_dcd_change);
3508
3509 /**
3510 * uart_handle_cts_change - handle a change of clear-to-send state
3511 * @uport: uart_port structure for the open port
3512 * @active: new clear-to-send status
3513 *
3514 * Caller must hold uport->lock.
3515 */
uart_handle_cts_change(struct uart_port * uport,bool active)3516 void uart_handle_cts_change(struct uart_port *uport, bool active)
3517 {
3518 lockdep_assert_held_once(&uport->lock);
3519
3520 uport->icount.cts++;
3521
3522 if (uart_softcts_mode(uport)) {
3523 if (uport->hw_stopped) {
3524 if (active) {
3525 uport->hw_stopped = false;
3526 uport->ops->start_tx(uport);
3527 uart_write_wakeup(uport);
3528 }
3529 } else {
3530 if (!active) {
3531 uport->hw_stopped = true;
3532 uport->ops->stop_tx(uport);
3533 }
3534 }
3535
3536 }
3537 }
3538 EXPORT_SYMBOL_GPL(uart_handle_cts_change);
3539
3540 /**
3541 * uart_insert_char - push a char to the uart layer
3542 *
3543 * User is responsible to call tty_flip_buffer_push when they are done with
3544 * insertion.
3545 *
3546 * @port: corresponding port
3547 * @status: state of the serial port RX buffer (LSR for 8250)
3548 * @overrun: mask of overrun bits in @status
3549 * @ch: character to push
3550 * @flag: flag for the character (see TTY_NORMAL and friends)
3551 */
uart_insert_char(struct uart_port * port,unsigned int status,unsigned int overrun,u8 ch,u8 flag)3552 void uart_insert_char(struct uart_port *port, unsigned int status,
3553 unsigned int overrun, u8 ch, u8 flag)
3554 {
3555 struct tty_port *tport = &port->state->port;
3556
3557 if ((status & port->ignore_status_mask & ~overrun) == 0)
3558 if (tty_insert_flip_char(tport, ch, flag) == 0)
3559 ++port->icount.buf_overrun;
3560
3561 /*
3562 * Overrun is special. Since it's reported immediately,
3563 * it doesn't affect the current character.
3564 */
3565 if (status & ~port->ignore_status_mask & overrun)
3566 if (tty_insert_flip_char(tport, 0, TTY_OVERRUN) == 0)
3567 ++port->icount.buf_overrun;
3568 }
3569 EXPORT_SYMBOL_GPL(uart_insert_char);
3570
3571 #ifdef CONFIG_MAGIC_SYSRQ_SERIAL
3572 static const u8 sysrq_toggle_seq[] = CONFIG_MAGIC_SYSRQ_SERIAL_SEQUENCE;
3573
uart_sysrq_on(struct work_struct * w)3574 static void uart_sysrq_on(struct work_struct *w)
3575 {
3576 int sysrq_toggle_seq_len = strlen(sysrq_toggle_seq);
3577
3578 sysrq_toggle_support(1);
3579 pr_info("SysRq is enabled by magic sequence '%*pE' on serial\n",
3580 sysrq_toggle_seq_len, sysrq_toggle_seq);
3581 }
3582 static DECLARE_WORK(sysrq_enable_work, uart_sysrq_on);
3583
3584 /**
3585 * uart_try_toggle_sysrq - Enables SysRq from serial line
3586 * @port: uart_port structure where char(s) after BREAK met
3587 * @ch: new character in the sequence after received BREAK
3588 *
3589 * Enables magic SysRq when the required sequence is met on port
3590 * (see CONFIG_MAGIC_SYSRQ_SERIAL_SEQUENCE).
3591 *
3592 * Returns: %false if @ch is out of enabling sequence and should be
3593 * handled some other way, %true if @ch was consumed.
3594 */
uart_try_toggle_sysrq(struct uart_port * port,u8 ch)3595 bool uart_try_toggle_sysrq(struct uart_port *port, u8 ch)
3596 {
3597 int sysrq_toggle_seq_len = strlen(sysrq_toggle_seq);
3598
3599 if (!sysrq_toggle_seq_len)
3600 return false;
3601
3602 BUILD_BUG_ON(ARRAY_SIZE(sysrq_toggle_seq) >= U8_MAX);
3603 if (sysrq_toggle_seq[port->sysrq_seq] != ch) {
3604 port->sysrq_seq = 0;
3605 return false;
3606 }
3607
3608 if (++port->sysrq_seq < sysrq_toggle_seq_len) {
3609 port->sysrq = jiffies + SYSRQ_TIMEOUT;
3610 return true;
3611 }
3612
3613 schedule_work(&sysrq_enable_work);
3614
3615 port->sysrq = 0;
3616 return true;
3617 }
3618 EXPORT_SYMBOL_GPL(uart_try_toggle_sysrq);
3619 #endif
3620
3621 /**
3622 * uart_get_rs485_mode() - retrieve rs485 properties for given uart
3623 * @port: uart device's target port
3624 *
3625 * This function implements the device tree binding described in
3626 * Documentation/devicetree/bindings/serial/rs485.txt.
3627 */
uart_get_rs485_mode(struct uart_port * port)3628 int uart_get_rs485_mode(struct uart_port *port)
3629 {
3630 struct serial_rs485 *rs485conf = &port->rs485;
3631 struct device *dev = port->dev;
3632 enum gpiod_flags dflags;
3633 struct gpio_desc *desc;
3634 u32 rs485_delay[2];
3635 int ret;
3636
3637 if (!(port->rs485_supported.flags & SER_RS485_ENABLED))
3638 return 0;
3639
3640 ret = device_property_read_u32_array(dev, "rs485-rts-delay",
3641 rs485_delay, 2);
3642 if (!ret) {
3643 rs485conf->delay_rts_before_send = rs485_delay[0];
3644 rs485conf->delay_rts_after_send = rs485_delay[1];
3645 } else {
3646 rs485conf->delay_rts_before_send = 0;
3647 rs485conf->delay_rts_after_send = 0;
3648 }
3649
3650 uart_sanitize_serial_rs485_delays(port, rs485conf);
3651
3652 /*
3653 * Clear full-duplex and enabled flags, set RTS polarity to active high
3654 * to get to a defined state with the following properties:
3655 */
3656 rs485conf->flags &= ~(SER_RS485_RX_DURING_TX | SER_RS485_ENABLED |
3657 SER_RS485_TERMINATE_BUS |
3658 SER_RS485_RTS_AFTER_SEND);
3659 rs485conf->flags |= SER_RS485_RTS_ON_SEND;
3660
3661 if (device_property_read_bool(dev, "rs485-rx-during-tx"))
3662 rs485conf->flags |= SER_RS485_RX_DURING_TX;
3663
3664 if (device_property_read_bool(dev, "linux,rs485-enabled-at-boot-time"))
3665 rs485conf->flags |= SER_RS485_ENABLED;
3666
3667 if (device_property_read_bool(dev, "rs485-rts-active-low")) {
3668 rs485conf->flags &= ~SER_RS485_RTS_ON_SEND;
3669 rs485conf->flags |= SER_RS485_RTS_AFTER_SEND;
3670 }
3671
3672 /*
3673 * Disabling termination by default is the safe choice: Else if many
3674 * bus participants enable it, no communication is possible at all.
3675 * Works fine for short cables and users may enable for longer cables.
3676 */
3677 desc = devm_gpiod_get_optional(dev, "rs485-term", GPIOD_OUT_LOW);
3678 if (IS_ERR(desc))
3679 return dev_err_probe(dev, PTR_ERR(desc), "Cannot get rs485-term-gpios\n");
3680 port->rs485_term_gpio = desc;
3681 if (port->rs485_term_gpio)
3682 port->rs485_supported.flags |= SER_RS485_TERMINATE_BUS;
3683
3684 dflags = (rs485conf->flags & SER_RS485_RX_DURING_TX) ?
3685 GPIOD_OUT_HIGH : GPIOD_OUT_LOW;
3686 desc = devm_gpiod_get_optional(dev, "rs485-rx-during-tx", dflags);
3687 if (IS_ERR(desc))
3688 return dev_err_probe(dev, PTR_ERR(desc), "Cannot get rs485-rx-during-tx-gpios\n");
3689 port->rs485_rx_during_tx_gpio = desc;
3690 if (port->rs485_rx_during_tx_gpio)
3691 port->rs485_supported.flags |= SER_RS485_RX_DURING_TX;
3692
3693 return 0;
3694 }
3695 EXPORT_SYMBOL_GPL(uart_get_rs485_mode);
3696
3697 /* Compile-time assertions for serial_rs485 layout */
3698 static_assert(offsetof(struct serial_rs485, padding) ==
3699 (offsetof(struct serial_rs485, delay_rts_after_send) + sizeof(__u32)));
3700 static_assert(offsetof(struct serial_rs485, padding1) ==
3701 offsetof(struct serial_rs485, padding[1]));
3702 static_assert((offsetof(struct serial_rs485, padding[4]) + sizeof(__u32)) ==
3703 sizeof(struct serial_rs485));
3704
3705 MODULE_DESCRIPTION("Serial driver core");
3706 MODULE_LICENSE("GPL");
3707