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 (!capable(CAP_SYS_ADMIN)) {
880 retval = -EPERM;
881 if (change_irq || change_port ||
882 (new_info->baud_base != uport->uartclk / 16) ||
883 (close_delay != port->close_delay) ||
884 (closing_wait != port->closing_wait) ||
885 (new_info->xmit_fifo_size &&
886 new_info->xmit_fifo_size != uport->fifosize) ||
887 (((new_flags ^ old_flags) & ~UPF_USR_MASK) != 0))
888 goto exit;
889 uport->flags = ((uport->flags & ~UPF_USR_MASK) |
890 (new_flags & UPF_USR_MASK));
891 uport->custom_divisor = new_info->custom_divisor;
892 goto check_and_exit;
893 }
894
895 if (change_irq || change_port) {
896 retval = security_locked_down(LOCKDOWN_TIOCSSERIAL);
897 if (retval)
898 goto exit;
899 }
900
901 /*
902 * Ask the low level driver to verify the settings.
903 */
904 if (uport->ops->verify_port)
905 retval = uport->ops->verify_port(uport, new_info);
906
907 if ((new_info->irq >= nr_irqs) || (new_info->irq < 0) ||
908 (new_info->baud_base < 9600))
909 retval = -EINVAL;
910
911 if (retval)
912 goto exit;
913
914 if (change_port || change_irq) {
915 retval = -EBUSY;
916
917 /*
918 * Make sure that we are the sole user of this port.
919 */
920 if (tty_port_users(port) > 1)
921 goto exit;
922
923 /*
924 * We need to shutdown the serial port at the old
925 * port/type/irq combination.
926 */
927 uart_shutdown(tty, state);
928 }
929
930 if (change_port) {
931 unsigned long old_iobase, old_mapbase;
932 unsigned int old_type, old_iotype, old_hub6, old_shift;
933
934 old_iobase = uport->iobase;
935 old_mapbase = uport->mapbase;
936 old_type = uport->type;
937 old_hub6 = uport->hub6;
938 old_iotype = uport->iotype;
939 old_shift = uport->regshift;
940
941 /*
942 * Free and release old regions
943 */
944 if (old_type != PORT_UNKNOWN && uport->ops->release_port)
945 uport->ops->release_port(uport);
946
947 uport->iobase = new_port;
948 uport->type = new_info->type;
949 uport->hub6 = new_info->hub6;
950 uport->iotype = new_info->io_type;
951 uport->regshift = new_info->iomem_reg_shift;
952 uport->mapbase = (unsigned long)new_info->iomem_base;
953
954 /*
955 * Claim and map the new regions
956 */
957 if (uport->type != PORT_UNKNOWN && uport->ops->request_port) {
958 retval = uport->ops->request_port(uport);
959 } else {
960 /* Always success - Jean II */
961 retval = 0;
962 }
963
964 /*
965 * If we fail to request resources for the
966 * new port, try to restore the old settings.
967 */
968 if (retval) {
969 uport->iobase = old_iobase;
970 uport->type = old_type;
971 uport->hub6 = old_hub6;
972 uport->iotype = old_iotype;
973 uport->regshift = old_shift;
974 uport->mapbase = old_mapbase;
975
976 if (old_type != PORT_UNKNOWN) {
977 retval = uport->ops->request_port(uport);
978 /*
979 * If we failed to restore the old settings,
980 * we fail like this.
981 */
982 if (retval)
983 uport->type = PORT_UNKNOWN;
984
985 /*
986 * We failed anyway.
987 */
988 retval = -EBUSY;
989 }
990
991 /* Added to return the correct error -Ram Gupta */
992 goto exit;
993 }
994 }
995
996 if (change_irq)
997 uport->irq = new_info->irq;
998 if (!(uport->flags & UPF_FIXED_PORT))
999 uport->uartclk = new_info->baud_base * 16;
1000 uport->flags = (uport->flags & ~UPF_CHANGE_MASK) |
1001 (new_flags & UPF_CHANGE_MASK);
1002 uport->custom_divisor = new_info->custom_divisor;
1003 port->close_delay = close_delay;
1004 port->closing_wait = closing_wait;
1005 if (new_info->xmit_fifo_size)
1006 uport->fifosize = new_info->xmit_fifo_size;
1007
1008 check_and_exit:
1009 retval = 0;
1010 if (uport->type == PORT_UNKNOWN)
1011 goto exit;
1012 if (tty_port_initialized(port)) {
1013 if (((old_flags ^ uport->flags) & UPF_SPD_MASK) ||
1014 old_custom_divisor != uport->custom_divisor) {
1015 /*
1016 * If they're setting up a custom divisor or speed,
1017 * instead of clearing it, then bitch about it.
1018 */
1019 if (uport->flags & UPF_SPD_MASK) {
1020 dev_notice_ratelimited(uport->dev,
1021 "%s sets custom speed on %s. This is deprecated.\n",
1022 current->comm,
1023 tty_name(port->tty));
1024 }
1025 uart_change_line_settings(tty, state, NULL);
1026 }
1027 } else {
1028 retval = uart_startup(tty, state, true);
1029 if (retval == 0)
1030 tty_port_set_initialized(port, true);
1031 if (retval > 0)
1032 retval = 0;
1033 }
1034 exit:
1035 return retval;
1036 }
1037
uart_set_info_user(struct tty_struct * tty,struct serial_struct * ss)1038 static int uart_set_info_user(struct tty_struct *tty, struct serial_struct *ss)
1039 {
1040 struct uart_state *state = tty->driver_data;
1041 struct tty_port *port = &state->port;
1042 int retval;
1043
1044 down_write(&tty->termios_rwsem);
1045 /*
1046 * This semaphore protects port->count. It is also
1047 * very useful to prevent opens. Also, take the
1048 * port configuration semaphore to make sure that a
1049 * module insertion/removal doesn't change anything
1050 * under us.
1051 */
1052 mutex_lock(&port->mutex);
1053 retval = uart_set_info(tty, port, state, ss);
1054 mutex_unlock(&port->mutex);
1055 up_write(&tty->termios_rwsem);
1056 return retval;
1057 }
1058
1059 /**
1060 * uart_get_lsr_info - get line status register info
1061 * @tty: tty associated with the UART
1062 * @state: UART being queried
1063 * @value: returned modem value
1064 */
uart_get_lsr_info(struct tty_struct * tty,struct uart_state * state,unsigned int __user * value)1065 static int uart_get_lsr_info(struct tty_struct *tty,
1066 struct uart_state *state, unsigned int __user *value)
1067 {
1068 struct uart_port *uport = uart_port_check(state);
1069 unsigned int result;
1070
1071 result = uport->ops->tx_empty(uport);
1072
1073 /*
1074 * If we're about to load something into the transmit
1075 * register, we'll pretend the transmitter isn't empty to
1076 * avoid a race condition (depending on when the transmit
1077 * interrupt happens).
1078 */
1079 if (uport->x_char ||
1080 ((uart_circ_chars_pending(&state->xmit) > 0) &&
1081 !uart_tx_stopped(uport)))
1082 result &= ~TIOCSER_TEMT;
1083
1084 return put_user(result, value);
1085 }
1086
uart_tiocmget(struct tty_struct * tty)1087 static int uart_tiocmget(struct tty_struct *tty)
1088 {
1089 struct uart_state *state = tty->driver_data;
1090 struct tty_port *port = &state->port;
1091 struct uart_port *uport;
1092 int result = -EIO;
1093
1094 mutex_lock(&port->mutex);
1095 uport = uart_port_check(state);
1096 if (!uport)
1097 goto out;
1098
1099 if (!tty_io_error(tty)) {
1100 result = uport->mctrl;
1101 spin_lock_irq(&uport->lock);
1102 result |= uport->ops->get_mctrl(uport);
1103 spin_unlock_irq(&uport->lock);
1104 }
1105 out:
1106 mutex_unlock(&port->mutex);
1107 return result;
1108 }
1109
1110 static int
uart_tiocmset(struct tty_struct * tty,unsigned int set,unsigned int clear)1111 uart_tiocmset(struct tty_struct *tty, unsigned int set, unsigned int clear)
1112 {
1113 struct uart_state *state = tty->driver_data;
1114 struct tty_port *port = &state->port;
1115 struct uart_port *uport;
1116 int ret = -EIO;
1117
1118 mutex_lock(&port->mutex);
1119 uport = uart_port_check(state);
1120 if (!uport)
1121 goto out;
1122
1123 if (!tty_io_error(tty)) {
1124 uart_update_mctrl(uport, set, clear);
1125 ret = 0;
1126 }
1127 out:
1128 mutex_unlock(&port->mutex);
1129 return ret;
1130 }
1131
uart_break_ctl(struct tty_struct * tty,int break_state)1132 static int uart_break_ctl(struct tty_struct *tty, int break_state)
1133 {
1134 struct uart_state *state = tty->driver_data;
1135 struct tty_port *port = &state->port;
1136 struct uart_port *uport;
1137 int ret = -EIO;
1138
1139 mutex_lock(&port->mutex);
1140 uport = uart_port_check(state);
1141 if (!uport)
1142 goto out;
1143
1144 if (uport->type != PORT_UNKNOWN && uport->ops->break_ctl)
1145 uport->ops->break_ctl(uport, break_state);
1146 ret = 0;
1147 out:
1148 mutex_unlock(&port->mutex);
1149 return ret;
1150 }
1151
uart_do_autoconfig(struct tty_struct * tty,struct uart_state * state)1152 static int uart_do_autoconfig(struct tty_struct *tty, struct uart_state *state)
1153 {
1154 struct tty_port *port = &state->port;
1155 struct uart_port *uport;
1156 int flags, ret;
1157
1158 if (!capable(CAP_SYS_ADMIN))
1159 return -EPERM;
1160
1161 /*
1162 * Take the per-port semaphore. This prevents count from
1163 * changing, and hence any extra opens of the port while
1164 * we're auto-configuring.
1165 */
1166 if (mutex_lock_interruptible(&port->mutex))
1167 return -ERESTARTSYS;
1168
1169 uport = uart_port_check(state);
1170 if (!uport) {
1171 ret = -EIO;
1172 goto out;
1173 }
1174
1175 ret = -EBUSY;
1176 if (tty_port_users(port) == 1) {
1177 uart_shutdown(tty, state);
1178
1179 /*
1180 * If we already have a port type configured,
1181 * we must release its resources.
1182 */
1183 if (uport->type != PORT_UNKNOWN && uport->ops->release_port)
1184 uport->ops->release_port(uport);
1185
1186 flags = UART_CONFIG_TYPE;
1187 if (uport->flags & UPF_AUTO_IRQ)
1188 flags |= UART_CONFIG_IRQ;
1189
1190 /*
1191 * This will claim the ports resources if
1192 * a port is found.
1193 */
1194 uport->ops->config_port(uport, flags);
1195
1196 ret = uart_startup(tty, state, true);
1197 if (ret == 0)
1198 tty_port_set_initialized(port, true);
1199 if (ret > 0)
1200 ret = 0;
1201 }
1202 out:
1203 mutex_unlock(&port->mutex);
1204 return ret;
1205 }
1206
uart_enable_ms(struct uart_port * uport)1207 static void uart_enable_ms(struct uart_port *uport)
1208 {
1209 /*
1210 * Force modem status interrupts on
1211 */
1212 if (uport->ops->enable_ms)
1213 uport->ops->enable_ms(uport);
1214 }
1215
1216 /*
1217 * Wait for any of the 4 modem inputs (DCD,RI,DSR,CTS) to change
1218 * - mask passed in arg for lines of interest
1219 * (use |'ed TIOCM_RNG/DSR/CD/CTS for masking)
1220 * Caller should use TIOCGICOUNT to see which one it was
1221 *
1222 * FIXME: This wants extracting into a common all driver implementation
1223 * of TIOCMWAIT using tty_port.
1224 */
uart_wait_modem_status(struct uart_state * state,unsigned long arg)1225 static int uart_wait_modem_status(struct uart_state *state, unsigned long arg)
1226 {
1227 struct uart_port *uport;
1228 struct tty_port *port = &state->port;
1229 DECLARE_WAITQUEUE(wait, current);
1230 struct uart_icount cprev, cnow;
1231 int ret;
1232
1233 /*
1234 * note the counters on entry
1235 */
1236 uport = uart_port_ref(state);
1237 if (!uport)
1238 return -EIO;
1239 spin_lock_irq(&uport->lock);
1240 memcpy(&cprev, &uport->icount, sizeof(struct uart_icount));
1241 uart_enable_ms(uport);
1242 spin_unlock_irq(&uport->lock);
1243
1244 add_wait_queue(&port->delta_msr_wait, &wait);
1245 for (;;) {
1246 spin_lock_irq(&uport->lock);
1247 memcpy(&cnow, &uport->icount, sizeof(struct uart_icount));
1248 spin_unlock_irq(&uport->lock);
1249
1250 set_current_state(TASK_INTERRUPTIBLE);
1251
1252 if (((arg & TIOCM_RNG) && (cnow.rng != cprev.rng)) ||
1253 ((arg & TIOCM_DSR) && (cnow.dsr != cprev.dsr)) ||
1254 ((arg & TIOCM_CD) && (cnow.dcd != cprev.dcd)) ||
1255 ((arg & TIOCM_CTS) && (cnow.cts != cprev.cts))) {
1256 ret = 0;
1257 break;
1258 }
1259
1260 schedule();
1261
1262 /* see if a signal did it */
1263 if (signal_pending(current)) {
1264 ret = -ERESTARTSYS;
1265 break;
1266 }
1267
1268 cprev = cnow;
1269 }
1270 __set_current_state(TASK_RUNNING);
1271 remove_wait_queue(&port->delta_msr_wait, &wait);
1272 uart_port_deref(uport);
1273
1274 return ret;
1275 }
1276
1277 /*
1278 * Get counter of input serial line interrupts (DCD,RI,DSR,CTS)
1279 * Return: write counters to the user passed counter struct
1280 * NB: both 1->0 and 0->1 transitions are counted except for
1281 * RI where only 0->1 is counted.
1282 */
uart_get_icount(struct tty_struct * tty,struct serial_icounter_struct * icount)1283 static int uart_get_icount(struct tty_struct *tty,
1284 struct serial_icounter_struct *icount)
1285 {
1286 struct uart_state *state = tty->driver_data;
1287 struct uart_icount cnow;
1288 struct uart_port *uport;
1289
1290 uport = uart_port_ref(state);
1291 if (!uport)
1292 return -EIO;
1293 spin_lock_irq(&uport->lock);
1294 memcpy(&cnow, &uport->icount, sizeof(struct uart_icount));
1295 spin_unlock_irq(&uport->lock);
1296 uart_port_deref(uport);
1297
1298 icount->cts = cnow.cts;
1299 icount->dsr = cnow.dsr;
1300 icount->rng = cnow.rng;
1301 icount->dcd = cnow.dcd;
1302 icount->rx = cnow.rx;
1303 icount->tx = cnow.tx;
1304 icount->frame = cnow.frame;
1305 icount->overrun = cnow.overrun;
1306 icount->parity = cnow.parity;
1307 icount->brk = cnow.brk;
1308 icount->buf_overrun = cnow.buf_overrun;
1309
1310 return 0;
1311 }
1312
1313 #define SER_RS485_LEGACY_FLAGS (SER_RS485_ENABLED | SER_RS485_RTS_ON_SEND | \
1314 SER_RS485_RTS_AFTER_SEND | SER_RS485_RX_DURING_TX | \
1315 SER_RS485_TERMINATE_BUS)
1316
uart_check_rs485_flags(struct uart_port * port,struct serial_rs485 * rs485)1317 static int uart_check_rs485_flags(struct uart_port *port, struct serial_rs485 *rs485)
1318 {
1319 u32 flags = rs485->flags;
1320
1321 /* Don't return -EINVAL for unsupported legacy flags */
1322 flags &= ~SER_RS485_LEGACY_FLAGS;
1323
1324 /*
1325 * For any bit outside of the legacy ones that is not supported by
1326 * the driver, return -EINVAL.
1327 */
1328 if (flags & ~port->rs485_supported.flags)
1329 return -EINVAL;
1330
1331 /* Asking for address w/o addressing mode? */
1332 if (!(rs485->flags & SER_RS485_ADDRB) &&
1333 (rs485->flags & (SER_RS485_ADDR_RECV|SER_RS485_ADDR_DEST)))
1334 return -EINVAL;
1335
1336 /* Address given but not enabled? */
1337 if (!(rs485->flags & SER_RS485_ADDR_RECV) && rs485->addr_recv)
1338 return -EINVAL;
1339 if (!(rs485->flags & SER_RS485_ADDR_DEST) && rs485->addr_dest)
1340 return -EINVAL;
1341
1342 return 0;
1343 }
1344
uart_sanitize_serial_rs485_delays(struct uart_port * port,struct serial_rs485 * rs485)1345 static void uart_sanitize_serial_rs485_delays(struct uart_port *port,
1346 struct serial_rs485 *rs485)
1347 {
1348 if (!port->rs485_supported.delay_rts_before_send) {
1349 if (rs485->delay_rts_before_send) {
1350 dev_warn_ratelimited(port->dev,
1351 "%s (%d): RTS delay before sending not supported\n",
1352 port->name, port->line);
1353 }
1354 rs485->delay_rts_before_send = 0;
1355 } else if (rs485->delay_rts_before_send > RS485_MAX_RTS_DELAY) {
1356 rs485->delay_rts_before_send = RS485_MAX_RTS_DELAY;
1357 dev_warn_ratelimited(port->dev,
1358 "%s (%d): RTS delay before sending clamped to %u ms\n",
1359 port->name, port->line, rs485->delay_rts_before_send);
1360 }
1361
1362 if (!port->rs485_supported.delay_rts_after_send) {
1363 if (rs485->delay_rts_after_send) {
1364 dev_warn_ratelimited(port->dev,
1365 "%s (%d): RTS delay after sending not supported\n",
1366 port->name, port->line);
1367 }
1368 rs485->delay_rts_after_send = 0;
1369 } else if (rs485->delay_rts_after_send > RS485_MAX_RTS_DELAY) {
1370 rs485->delay_rts_after_send = RS485_MAX_RTS_DELAY;
1371 dev_warn_ratelimited(port->dev,
1372 "%s (%d): RTS delay after sending clamped to %u ms\n",
1373 port->name, port->line, rs485->delay_rts_after_send);
1374 }
1375 }
1376
uart_sanitize_serial_rs485(struct uart_port * port,struct serial_rs485 * rs485)1377 static void uart_sanitize_serial_rs485(struct uart_port *port, struct serial_rs485 *rs485)
1378 {
1379 u32 supported_flags = port->rs485_supported.flags;
1380
1381 if (!(rs485->flags & SER_RS485_ENABLED)) {
1382 memset(rs485, 0, sizeof(*rs485));
1383 return;
1384 }
1385
1386 rs485->flags &= supported_flags;
1387
1388 /* Pick sane settings if the user hasn't */
1389 if (!(rs485->flags & SER_RS485_RTS_ON_SEND) ==
1390 !(rs485->flags & SER_RS485_RTS_AFTER_SEND)) {
1391 if (supported_flags & SER_RS485_RTS_ON_SEND) {
1392 rs485->flags |= SER_RS485_RTS_ON_SEND;
1393 rs485->flags &= ~SER_RS485_RTS_AFTER_SEND;
1394
1395 dev_warn_ratelimited(port->dev,
1396 "%s (%d): invalid RTS setting, using RTS_ON_SEND instead\n",
1397 port->name, port->line);
1398 } else {
1399 rs485->flags |= SER_RS485_RTS_AFTER_SEND;
1400 rs485->flags &= ~SER_RS485_RTS_ON_SEND;
1401
1402 dev_warn_ratelimited(port->dev,
1403 "%s (%d): invalid RTS setting, using RTS_AFTER_SEND instead\n",
1404 port->name, port->line);
1405 }
1406 }
1407
1408 uart_sanitize_serial_rs485_delays(port, rs485);
1409
1410 /* Return clean padding area to userspace */
1411 memset(rs485->padding0, 0, sizeof(rs485->padding0));
1412 memset(rs485->padding1, 0, sizeof(rs485->padding1));
1413 }
1414
uart_set_rs485_termination(struct uart_port * port,const struct serial_rs485 * rs485)1415 static void uart_set_rs485_termination(struct uart_port *port,
1416 const struct serial_rs485 *rs485)
1417 {
1418 if (!(rs485->flags & SER_RS485_ENABLED))
1419 return;
1420
1421 gpiod_set_value_cansleep(port->rs485_term_gpio,
1422 !!(rs485->flags & SER_RS485_TERMINATE_BUS));
1423 }
1424
uart_set_rs485_rx_during_tx(struct uart_port * port,const struct serial_rs485 * rs485)1425 static void uart_set_rs485_rx_during_tx(struct uart_port *port,
1426 const struct serial_rs485 *rs485)
1427 {
1428 if (!(rs485->flags & SER_RS485_ENABLED))
1429 return;
1430
1431 gpiod_set_value_cansleep(port->rs485_rx_during_tx_gpio,
1432 !!(rs485->flags & SER_RS485_RX_DURING_TX));
1433 }
1434
uart_rs485_config(struct uart_port * port)1435 static int uart_rs485_config(struct uart_port *port)
1436 {
1437 struct serial_rs485 *rs485 = &port->rs485;
1438 unsigned long flags;
1439 int ret;
1440
1441 if (!(rs485->flags & SER_RS485_ENABLED))
1442 return 0;
1443
1444 uart_sanitize_serial_rs485(port, rs485);
1445 uart_set_rs485_termination(port, rs485);
1446 uart_set_rs485_rx_during_tx(port, rs485);
1447
1448 spin_lock_irqsave(&port->lock, flags);
1449 ret = port->rs485_config(port, NULL, rs485);
1450 spin_unlock_irqrestore(&port->lock, flags);
1451 if (ret) {
1452 memset(rs485, 0, sizeof(*rs485));
1453 /* unset GPIOs */
1454 gpiod_set_value_cansleep(port->rs485_term_gpio, 0);
1455 gpiod_set_value_cansleep(port->rs485_rx_during_tx_gpio, 0);
1456 }
1457
1458 return ret;
1459 }
1460
uart_get_rs485_config(struct uart_port * port,struct serial_rs485 __user * rs485)1461 static int uart_get_rs485_config(struct uart_port *port,
1462 struct serial_rs485 __user *rs485)
1463 {
1464 unsigned long flags;
1465 struct serial_rs485 aux;
1466
1467 spin_lock_irqsave(&port->lock, flags);
1468 aux = port->rs485;
1469 spin_unlock_irqrestore(&port->lock, flags);
1470
1471 if (copy_to_user(rs485, &aux, sizeof(aux)))
1472 return -EFAULT;
1473
1474 return 0;
1475 }
1476
uart_set_rs485_config(struct tty_struct * tty,struct uart_port * port,struct serial_rs485 __user * rs485_user)1477 static int uart_set_rs485_config(struct tty_struct *tty, struct uart_port *port,
1478 struct serial_rs485 __user *rs485_user)
1479 {
1480 struct serial_rs485 rs485;
1481 int ret;
1482 unsigned long flags;
1483
1484 if (!(port->rs485_supported.flags & SER_RS485_ENABLED))
1485 return -ENOTTY;
1486
1487 if (copy_from_user(&rs485, rs485_user, sizeof(*rs485_user)))
1488 return -EFAULT;
1489
1490 ret = uart_check_rs485_flags(port, &rs485);
1491 if (ret)
1492 return ret;
1493 uart_sanitize_serial_rs485(port, &rs485);
1494 uart_set_rs485_termination(port, &rs485);
1495 uart_set_rs485_rx_during_tx(port, &rs485);
1496
1497 spin_lock_irqsave(&port->lock, flags);
1498 ret = port->rs485_config(port, &tty->termios, &rs485);
1499 if (!ret) {
1500 port->rs485 = rs485;
1501
1502 /* Reset RTS and other mctrl lines when disabling RS485 */
1503 if (!(rs485.flags & SER_RS485_ENABLED))
1504 port->ops->set_mctrl(port, port->mctrl);
1505 }
1506 spin_unlock_irqrestore(&port->lock, flags);
1507 if (ret) {
1508 /* restore old GPIO settings */
1509 gpiod_set_value_cansleep(port->rs485_term_gpio,
1510 !!(port->rs485.flags & SER_RS485_TERMINATE_BUS));
1511 gpiod_set_value_cansleep(port->rs485_rx_during_tx_gpio,
1512 !!(port->rs485.flags & SER_RS485_RX_DURING_TX));
1513 return ret;
1514 }
1515
1516 if (copy_to_user(rs485_user, &port->rs485, sizeof(port->rs485)))
1517 return -EFAULT;
1518
1519 return 0;
1520 }
1521
uart_get_iso7816_config(struct uart_port * port,struct serial_iso7816 __user * iso7816)1522 static int uart_get_iso7816_config(struct uart_port *port,
1523 struct serial_iso7816 __user *iso7816)
1524 {
1525 unsigned long flags;
1526 struct serial_iso7816 aux;
1527
1528 if (!port->iso7816_config)
1529 return -ENOTTY;
1530
1531 spin_lock_irqsave(&port->lock, flags);
1532 aux = port->iso7816;
1533 spin_unlock_irqrestore(&port->lock, flags);
1534
1535 if (copy_to_user(iso7816, &aux, sizeof(aux)))
1536 return -EFAULT;
1537
1538 return 0;
1539 }
1540
uart_set_iso7816_config(struct uart_port * port,struct serial_iso7816 __user * iso7816_user)1541 static int uart_set_iso7816_config(struct uart_port *port,
1542 struct serial_iso7816 __user *iso7816_user)
1543 {
1544 struct serial_iso7816 iso7816;
1545 int i, ret;
1546 unsigned long flags;
1547
1548 if (!port->iso7816_config)
1549 return -ENOTTY;
1550
1551 if (copy_from_user(&iso7816, iso7816_user, sizeof(*iso7816_user)))
1552 return -EFAULT;
1553
1554 /*
1555 * There are 5 words reserved for future use. Check that userspace
1556 * doesn't put stuff in there to prevent breakages in the future.
1557 */
1558 for (i = 0; i < ARRAY_SIZE(iso7816.reserved); i++)
1559 if (iso7816.reserved[i])
1560 return -EINVAL;
1561
1562 spin_lock_irqsave(&port->lock, flags);
1563 ret = port->iso7816_config(port, &iso7816);
1564 spin_unlock_irqrestore(&port->lock, flags);
1565 if (ret)
1566 return ret;
1567
1568 if (copy_to_user(iso7816_user, &port->iso7816, sizeof(port->iso7816)))
1569 return -EFAULT;
1570
1571 return 0;
1572 }
1573
1574 /*
1575 * Called via sys_ioctl. We can use spin_lock_irq() here.
1576 */
1577 static int
uart_ioctl(struct tty_struct * tty,unsigned int cmd,unsigned long arg)1578 uart_ioctl(struct tty_struct *tty, unsigned int cmd, unsigned long arg)
1579 {
1580 struct uart_state *state = tty->driver_data;
1581 struct tty_port *port = &state->port;
1582 struct uart_port *uport;
1583 void __user *uarg = (void __user *)arg;
1584 int ret = -ENOIOCTLCMD;
1585
1586
1587 /*
1588 * These ioctls don't rely on the hardware to be present.
1589 */
1590 switch (cmd) {
1591 case TIOCSERCONFIG:
1592 down_write(&tty->termios_rwsem);
1593 ret = uart_do_autoconfig(tty, state);
1594 up_write(&tty->termios_rwsem);
1595 break;
1596 }
1597
1598 if (ret != -ENOIOCTLCMD)
1599 goto out;
1600
1601 if (tty_io_error(tty)) {
1602 ret = -EIO;
1603 goto out;
1604 }
1605
1606 /*
1607 * The following should only be used when hardware is present.
1608 */
1609 switch (cmd) {
1610 case TIOCMIWAIT:
1611 ret = uart_wait_modem_status(state, arg);
1612 break;
1613 }
1614
1615 if (ret != -ENOIOCTLCMD)
1616 goto out;
1617
1618 /* rs485_config requires more locking than others */
1619 if (cmd == TIOCSRS485)
1620 down_write(&tty->termios_rwsem);
1621
1622 mutex_lock(&port->mutex);
1623 uport = uart_port_check(state);
1624
1625 if (!uport || tty_io_error(tty)) {
1626 ret = -EIO;
1627 goto out_up;
1628 }
1629
1630 /*
1631 * All these rely on hardware being present and need to be
1632 * protected against the tty being hung up.
1633 */
1634
1635 switch (cmd) {
1636 case TIOCSERGETLSR: /* Get line status register */
1637 ret = uart_get_lsr_info(tty, state, uarg);
1638 break;
1639
1640 case TIOCGRS485:
1641 ret = uart_get_rs485_config(uport, uarg);
1642 break;
1643
1644 case TIOCSRS485:
1645 ret = uart_set_rs485_config(tty, uport, uarg);
1646 break;
1647
1648 case TIOCSISO7816:
1649 ret = uart_set_iso7816_config(state->uart_port, uarg);
1650 break;
1651
1652 case TIOCGISO7816:
1653 ret = uart_get_iso7816_config(state->uart_port, uarg);
1654 break;
1655 default:
1656 if (uport->ops->ioctl)
1657 ret = uport->ops->ioctl(uport, cmd, arg);
1658 break;
1659 }
1660 out_up:
1661 mutex_unlock(&port->mutex);
1662 if (cmd == TIOCSRS485)
1663 up_write(&tty->termios_rwsem);
1664 out:
1665 return ret;
1666 }
1667
uart_set_ldisc(struct tty_struct * tty)1668 static void uart_set_ldisc(struct tty_struct *tty)
1669 {
1670 struct uart_state *state = tty->driver_data;
1671 struct uart_port *uport;
1672 struct tty_port *port = &state->port;
1673
1674 if (!tty_port_initialized(port))
1675 return;
1676
1677 mutex_lock(&state->port.mutex);
1678 uport = uart_port_check(state);
1679 if (uport && uport->ops->set_ldisc)
1680 uport->ops->set_ldisc(uport, &tty->termios);
1681 mutex_unlock(&state->port.mutex);
1682 }
1683
uart_set_termios(struct tty_struct * tty,const struct ktermios * old_termios)1684 static void uart_set_termios(struct tty_struct *tty,
1685 const struct ktermios *old_termios)
1686 {
1687 struct uart_state *state = tty->driver_data;
1688 struct uart_port *uport;
1689 unsigned int cflag = tty->termios.c_cflag;
1690 unsigned int iflag_mask = IGNBRK|BRKINT|IGNPAR|PARMRK|INPCK;
1691 bool sw_changed = false;
1692
1693 mutex_lock(&state->port.mutex);
1694 uport = uart_port_check(state);
1695 if (!uport)
1696 goto out;
1697
1698 /*
1699 * Drivers doing software flow control also need to know
1700 * about changes to these input settings.
1701 */
1702 if (uport->flags & UPF_SOFT_FLOW) {
1703 iflag_mask |= IXANY|IXON|IXOFF;
1704 sw_changed =
1705 tty->termios.c_cc[VSTART] != old_termios->c_cc[VSTART] ||
1706 tty->termios.c_cc[VSTOP] != old_termios->c_cc[VSTOP];
1707 }
1708
1709 /*
1710 * These are the bits that are used to setup various
1711 * flags in the low level driver. We can ignore the Bfoo
1712 * bits in c_cflag; c_[io]speed will always be set
1713 * appropriately by set_termios() in tty_ioctl.c
1714 */
1715 if ((cflag ^ old_termios->c_cflag) == 0 &&
1716 tty->termios.c_ospeed == old_termios->c_ospeed &&
1717 tty->termios.c_ispeed == old_termios->c_ispeed &&
1718 ((tty->termios.c_iflag ^ old_termios->c_iflag) & iflag_mask) == 0 &&
1719 !sw_changed) {
1720 goto out;
1721 }
1722
1723 uart_change_line_settings(tty, state, old_termios);
1724 /* reload cflag from termios; port driver may have overridden flags */
1725 cflag = tty->termios.c_cflag;
1726
1727 /* Handle transition to B0 status */
1728 if (((old_termios->c_cflag & CBAUD) != B0) && ((cflag & CBAUD) == B0))
1729 uart_clear_mctrl(uport, TIOCM_RTS | TIOCM_DTR);
1730 /* Handle transition away from B0 status */
1731 else if (((old_termios->c_cflag & CBAUD) == B0) && ((cflag & CBAUD) != B0)) {
1732 unsigned int mask = TIOCM_DTR;
1733
1734 if (!(cflag & CRTSCTS) || !tty_throttled(tty))
1735 mask |= TIOCM_RTS;
1736 uart_set_mctrl(uport, mask);
1737 }
1738 out:
1739 mutex_unlock(&state->port.mutex);
1740 }
1741
1742 /*
1743 * Calls to uart_close() are serialised via the tty_lock in
1744 * drivers/tty/tty_io.c:tty_release()
1745 * drivers/tty/tty_io.c:do_tty_hangup()
1746 */
uart_close(struct tty_struct * tty,struct file * filp)1747 static void uart_close(struct tty_struct *tty, struct file *filp)
1748 {
1749 struct uart_state *state = tty->driver_data;
1750
1751 if (!state) {
1752 struct uart_driver *drv = tty->driver->driver_state;
1753 struct tty_port *port;
1754
1755 state = drv->state + tty->index;
1756 port = &state->port;
1757 spin_lock_irq(&port->lock);
1758 --port->count;
1759 spin_unlock_irq(&port->lock);
1760 return;
1761 }
1762
1763 pr_debug("uart_close(%d) called\n", tty->index);
1764
1765 tty_port_close(tty->port, tty, filp);
1766 }
1767
uart_tty_port_shutdown(struct tty_port * port)1768 static void uart_tty_port_shutdown(struct tty_port *port)
1769 {
1770 struct uart_state *state = container_of(port, struct uart_state, port);
1771 struct uart_port *uport = uart_port_check(state);
1772 char *buf;
1773
1774 /*
1775 * At this point, we stop accepting input. To do this, we
1776 * disable the receive line status interrupts.
1777 */
1778 if (WARN(!uport, "detached port still initialized!\n"))
1779 return;
1780
1781 spin_lock_irq(&uport->lock);
1782 uport->ops->stop_rx(uport);
1783 spin_unlock_irq(&uport->lock);
1784
1785 serial_base_port_shutdown(uport);
1786 uart_port_shutdown(port);
1787
1788 /*
1789 * It's possible for shutdown to be called after suspend if we get
1790 * a DCD drop (hangup) at just the right time. Clear suspended bit so
1791 * we don't try to resume a port that has been shutdown.
1792 */
1793 tty_port_set_suspended(port, false);
1794
1795 /*
1796 * Free the transmit buffer.
1797 */
1798 spin_lock_irq(&uport->lock);
1799 uart_circ_clear(&state->xmit);
1800 buf = state->xmit.buf;
1801 state->xmit.buf = NULL;
1802 spin_unlock_irq(&uport->lock);
1803
1804 free_page((unsigned long)buf);
1805
1806 uart_change_pm(state, UART_PM_STATE_OFF);
1807 }
1808
uart_wait_until_sent(struct tty_struct * tty,int timeout)1809 static void uart_wait_until_sent(struct tty_struct *tty, int timeout)
1810 {
1811 struct uart_state *state = tty->driver_data;
1812 struct uart_port *port;
1813 unsigned long char_time, expire, fifo_timeout;
1814
1815 port = uart_port_ref(state);
1816 if (!port)
1817 return;
1818
1819 if (port->type == PORT_UNKNOWN || port->fifosize == 0) {
1820 uart_port_deref(port);
1821 return;
1822 }
1823
1824 /*
1825 * Set the check interval to be 1/5 of the estimated time to
1826 * send a single character, and make it at least 1. The check
1827 * interval should also be less than the timeout.
1828 *
1829 * Note: we have to use pretty tight timings here to satisfy
1830 * the NIST-PCTS.
1831 */
1832 char_time = max(nsecs_to_jiffies(port->frame_time / 5), 1UL);
1833
1834 if (timeout && timeout < char_time)
1835 char_time = timeout;
1836
1837 if (!uart_cts_enabled(port)) {
1838 /*
1839 * If the transmitter hasn't cleared in twice the approximate
1840 * amount of time to send the entire FIFO, it probably won't
1841 * ever clear. This assumes the UART isn't doing flow
1842 * control, which is currently the case. Hence, if it ever
1843 * takes longer than FIFO timeout, this is probably due to a
1844 * UART bug of some kind. So, we clamp the timeout parameter at
1845 * 2 * FIFO timeout.
1846 */
1847 fifo_timeout = uart_fifo_timeout(port);
1848 if (timeout == 0 || timeout > 2 * fifo_timeout)
1849 timeout = 2 * fifo_timeout;
1850 }
1851
1852 expire = jiffies + timeout;
1853
1854 pr_debug("uart_wait_until_sent(%d), jiffies=%lu, expire=%lu...\n",
1855 port->line, jiffies, expire);
1856
1857 /*
1858 * Check whether the transmitter is empty every 'char_time'.
1859 * 'timeout' / 'expire' give us the maximum amount of time
1860 * we wait.
1861 */
1862 while (!port->ops->tx_empty(port)) {
1863 msleep_interruptible(jiffies_to_msecs(char_time));
1864 if (signal_pending(current))
1865 break;
1866 if (timeout && time_after(jiffies, expire))
1867 break;
1868 }
1869 uart_port_deref(port);
1870 }
1871
1872 /*
1873 * Calls to uart_hangup() are serialised by the tty_lock in
1874 * drivers/tty/tty_io.c:do_tty_hangup()
1875 * This runs from a workqueue and can sleep for a _short_ time only.
1876 */
uart_hangup(struct tty_struct * tty)1877 static void uart_hangup(struct tty_struct *tty)
1878 {
1879 struct uart_state *state = tty->driver_data;
1880 struct tty_port *port = &state->port;
1881 struct uart_port *uport;
1882 unsigned long flags;
1883
1884 pr_debug("uart_hangup(%d)\n", tty->index);
1885
1886 mutex_lock(&port->mutex);
1887 uport = uart_port_check(state);
1888 WARN(!uport, "hangup of detached port!\n");
1889
1890 if (tty_port_active(port)) {
1891 uart_flush_buffer(tty);
1892 uart_shutdown(tty, state);
1893 spin_lock_irqsave(&port->lock, flags);
1894 port->count = 0;
1895 spin_unlock_irqrestore(&port->lock, flags);
1896 tty_port_set_active(port, false);
1897 tty_port_tty_set(port, NULL);
1898 if (uport && !uart_console(uport))
1899 uart_change_pm(state, UART_PM_STATE_OFF);
1900 wake_up_interruptible(&port->open_wait);
1901 wake_up_interruptible(&port->delta_msr_wait);
1902 }
1903 mutex_unlock(&port->mutex);
1904 }
1905
1906 /* uport == NULL if uart_port has already been removed */
uart_port_shutdown(struct tty_port * port)1907 static void uart_port_shutdown(struct tty_port *port)
1908 {
1909 struct uart_state *state = container_of(port, struct uart_state, port);
1910 struct uart_port *uport = uart_port_check(state);
1911
1912 /*
1913 * clear delta_msr_wait queue to avoid mem leaks: we may free
1914 * the irq here so the queue might never be woken up. Note
1915 * that we won't end up waiting on delta_msr_wait again since
1916 * any outstanding file descriptors should be pointing at
1917 * hung_up_tty_fops now.
1918 */
1919 wake_up_interruptible(&port->delta_msr_wait);
1920
1921 if (uport) {
1922 /* Free the IRQ and disable the port. */
1923 uport->ops->shutdown(uport);
1924
1925 /* Ensure that the IRQ handler isn't running on another CPU. */
1926 synchronize_irq(uport->irq);
1927 }
1928 }
1929
uart_carrier_raised(struct tty_port * port)1930 static bool uart_carrier_raised(struct tty_port *port)
1931 {
1932 struct uart_state *state = container_of(port, struct uart_state, port);
1933 struct uart_port *uport;
1934 int mctrl;
1935
1936 uport = uart_port_ref(state);
1937 /*
1938 * Should never observe uport == NULL since checks for hangup should
1939 * abort the tty_port_block_til_ready() loop before checking for carrier
1940 * raised -- but report carrier raised if it does anyway so open will
1941 * continue and not sleep
1942 */
1943 if (WARN_ON(!uport))
1944 return true;
1945 spin_lock_irq(&uport->lock);
1946 uart_enable_ms(uport);
1947 mctrl = uport->ops->get_mctrl(uport);
1948 spin_unlock_irq(&uport->lock);
1949 uart_port_deref(uport);
1950
1951 return mctrl & TIOCM_CAR;
1952 }
1953
uart_dtr_rts(struct tty_port * port,bool active)1954 static void uart_dtr_rts(struct tty_port *port, bool active)
1955 {
1956 struct uart_state *state = container_of(port, struct uart_state, port);
1957 struct uart_port *uport;
1958
1959 uport = uart_port_ref(state);
1960 if (!uport)
1961 return;
1962 uart_port_dtr_rts(uport, active);
1963 uart_port_deref(uport);
1964 }
1965
uart_install(struct tty_driver * driver,struct tty_struct * tty)1966 static int uart_install(struct tty_driver *driver, struct tty_struct *tty)
1967 {
1968 struct uart_driver *drv = driver->driver_state;
1969 struct uart_state *state = drv->state + tty->index;
1970
1971 tty->driver_data = state;
1972
1973 return tty_standard_install(driver, tty);
1974 }
1975
1976 /*
1977 * Calls to uart_open are serialised by the tty_lock in
1978 * drivers/tty/tty_io.c:tty_open()
1979 * Note that if this fails, then uart_close() _will_ be called.
1980 *
1981 * In time, we want to scrap the "opening nonpresent ports"
1982 * behaviour and implement an alternative way for setserial
1983 * to set base addresses/ports/types. This will allow us to
1984 * get rid of a certain amount of extra tests.
1985 */
uart_open(struct tty_struct * tty,struct file * filp)1986 static int uart_open(struct tty_struct *tty, struct file *filp)
1987 {
1988 struct uart_state *state = tty->driver_data;
1989 int retval;
1990
1991 retval = tty_port_open(&state->port, tty, filp);
1992 if (retval > 0)
1993 retval = 0;
1994
1995 return retval;
1996 }
1997
uart_port_activate(struct tty_port * port,struct tty_struct * tty)1998 static int uart_port_activate(struct tty_port *port, struct tty_struct *tty)
1999 {
2000 struct uart_state *state = container_of(port, struct uart_state, port);
2001 struct uart_port *uport;
2002 int ret;
2003
2004 uport = uart_port_check(state);
2005 if (!uport || uport->flags & UPF_DEAD)
2006 return -ENXIO;
2007
2008 /*
2009 * Start up the serial port.
2010 */
2011 ret = uart_startup(tty, state, false);
2012 if (ret > 0)
2013 tty_port_set_active(port, true);
2014
2015 return ret;
2016 }
2017
uart_type(struct uart_port * port)2018 static const char *uart_type(struct uart_port *port)
2019 {
2020 const char *str = NULL;
2021
2022 if (port->ops->type)
2023 str = port->ops->type(port);
2024
2025 if (!str)
2026 str = "unknown";
2027
2028 return str;
2029 }
2030
2031 #ifdef CONFIG_PROC_FS
2032
uart_line_info(struct seq_file * m,struct uart_driver * drv,int i)2033 static void uart_line_info(struct seq_file *m, struct uart_driver *drv, int i)
2034 {
2035 struct uart_state *state = drv->state + i;
2036 struct tty_port *port = &state->port;
2037 enum uart_pm_state pm_state;
2038 struct uart_port *uport;
2039 char stat_buf[32];
2040 unsigned int status;
2041 int mmio;
2042
2043 mutex_lock(&port->mutex);
2044 uport = uart_port_check(state);
2045 if (!uport)
2046 goto out;
2047
2048 mmio = uport->iotype >= UPIO_MEM;
2049 seq_printf(m, "%d: uart:%s %s%08llX irq:%d",
2050 uport->line, uart_type(uport),
2051 mmio ? "mmio:0x" : "port:",
2052 mmio ? (unsigned long long)uport->mapbase
2053 : (unsigned long long)uport->iobase,
2054 uport->irq);
2055
2056 if (uport->type == PORT_UNKNOWN) {
2057 seq_putc(m, '\n');
2058 goto out;
2059 }
2060
2061 if (capable(CAP_SYS_ADMIN)) {
2062 pm_state = state->pm_state;
2063 if (pm_state != UART_PM_STATE_ON)
2064 uart_change_pm(state, UART_PM_STATE_ON);
2065 spin_lock_irq(&uport->lock);
2066 status = uport->ops->get_mctrl(uport);
2067 spin_unlock_irq(&uport->lock);
2068 if (pm_state != UART_PM_STATE_ON)
2069 uart_change_pm(state, pm_state);
2070
2071 seq_printf(m, " tx:%d rx:%d",
2072 uport->icount.tx, uport->icount.rx);
2073 if (uport->icount.frame)
2074 seq_printf(m, " fe:%d", uport->icount.frame);
2075 if (uport->icount.parity)
2076 seq_printf(m, " pe:%d", uport->icount.parity);
2077 if (uport->icount.brk)
2078 seq_printf(m, " brk:%d", uport->icount.brk);
2079 if (uport->icount.overrun)
2080 seq_printf(m, " oe:%d", uport->icount.overrun);
2081 if (uport->icount.buf_overrun)
2082 seq_printf(m, " bo:%d", uport->icount.buf_overrun);
2083
2084 #define INFOBIT(bit, str) \
2085 if (uport->mctrl & (bit)) \
2086 strncat(stat_buf, (str), sizeof(stat_buf) - \
2087 strlen(stat_buf) - 2)
2088 #define STATBIT(bit, str) \
2089 if (status & (bit)) \
2090 strncat(stat_buf, (str), sizeof(stat_buf) - \
2091 strlen(stat_buf) - 2)
2092
2093 stat_buf[0] = '\0';
2094 stat_buf[1] = '\0';
2095 INFOBIT(TIOCM_RTS, "|RTS");
2096 STATBIT(TIOCM_CTS, "|CTS");
2097 INFOBIT(TIOCM_DTR, "|DTR");
2098 STATBIT(TIOCM_DSR, "|DSR");
2099 STATBIT(TIOCM_CAR, "|CD");
2100 STATBIT(TIOCM_RNG, "|RI");
2101 if (stat_buf[0])
2102 stat_buf[0] = ' ';
2103
2104 seq_puts(m, stat_buf);
2105 }
2106 seq_putc(m, '\n');
2107 #undef STATBIT
2108 #undef INFOBIT
2109 out:
2110 mutex_unlock(&port->mutex);
2111 }
2112
uart_proc_show(struct seq_file * m,void * v)2113 static int uart_proc_show(struct seq_file *m, void *v)
2114 {
2115 struct tty_driver *ttydrv = m->private;
2116 struct uart_driver *drv = ttydrv->driver_state;
2117 int i;
2118
2119 seq_printf(m, "serinfo:1.0 driver%s%s revision:%s\n", "", "", "");
2120 for (i = 0; i < drv->nr; i++)
2121 uart_line_info(m, drv, i);
2122 return 0;
2123 }
2124 #endif
2125
uart_port_spin_lock_init(struct uart_port * port)2126 static void uart_port_spin_lock_init(struct uart_port *port)
2127 {
2128 spin_lock_init(&port->lock);
2129 lockdep_set_class(&port->lock, &port_lock_key);
2130 }
2131
2132 #if defined(CONFIG_SERIAL_CORE_CONSOLE) || defined(CONFIG_CONSOLE_POLL)
2133 /**
2134 * uart_console_write - write a console message to a serial port
2135 * @port: the port to write the message
2136 * @s: array of characters
2137 * @count: number of characters in string to write
2138 * @putchar: function to write character to port
2139 */
uart_console_write(struct uart_port * port,const char * s,unsigned int count,void (* putchar)(struct uart_port *,unsigned char))2140 void uart_console_write(struct uart_port *port, const char *s,
2141 unsigned int count,
2142 void (*putchar)(struct uart_port *, unsigned char))
2143 {
2144 unsigned int i;
2145
2146 for (i = 0; i < count; i++, s++) {
2147 if (*s == '\n')
2148 putchar(port, '\r');
2149 putchar(port, *s);
2150 }
2151 }
2152 EXPORT_SYMBOL_GPL(uart_console_write);
2153
2154 /**
2155 * uart_get_console - get uart port for console
2156 * @ports: ports to search in
2157 * @nr: number of @ports
2158 * @co: console to search for
2159 * Returns: uart_port for the console @co
2160 *
2161 * Check whether an invalid uart number has been specified (as @co->index), and
2162 * if so, search for the first available port that does have console support.
2163 */
2164 struct uart_port * __init
uart_get_console(struct uart_port * ports,int nr,struct console * co)2165 uart_get_console(struct uart_port *ports, int nr, struct console *co)
2166 {
2167 int idx = co->index;
2168
2169 if (idx < 0 || idx >= nr || (ports[idx].iobase == 0 &&
2170 ports[idx].membase == NULL))
2171 for (idx = 0; idx < nr; idx++)
2172 if (ports[idx].iobase != 0 ||
2173 ports[idx].membase != NULL)
2174 break;
2175
2176 co->index = idx;
2177
2178 return ports + idx;
2179 }
2180
2181 /**
2182 * uart_parse_earlycon - Parse earlycon options
2183 * @p: ptr to 2nd field (ie., just beyond '<name>,')
2184 * @iotype: ptr for decoded iotype (out)
2185 * @addr: ptr for decoded mapbase/iobase (out)
2186 * @options: ptr for <options> field; %NULL if not present (out)
2187 *
2188 * Decodes earlycon kernel command line parameters of the form:
2189 * * earlycon=<name>,io|mmio|mmio16|mmio32|mmio32be|mmio32native,<addr>,<options>
2190 * * console=<name>,io|mmio|mmio16|mmio32|mmio32be|mmio32native,<addr>,<options>
2191 *
2192 * The optional form:
2193 * * earlycon=<name>,0x<addr>,<options>
2194 * * console=<name>,0x<addr>,<options>
2195 *
2196 * is also accepted; the returned @iotype will be %UPIO_MEM.
2197 *
2198 * Returns: 0 on success or -%EINVAL on failure
2199 */
uart_parse_earlycon(char * p,unsigned char * iotype,resource_size_t * addr,char ** options)2200 int uart_parse_earlycon(char *p, unsigned char *iotype, resource_size_t *addr,
2201 char **options)
2202 {
2203 if (strncmp(p, "mmio,", 5) == 0) {
2204 *iotype = UPIO_MEM;
2205 p += 5;
2206 } else if (strncmp(p, "mmio16,", 7) == 0) {
2207 *iotype = UPIO_MEM16;
2208 p += 7;
2209 } else if (strncmp(p, "mmio32,", 7) == 0) {
2210 *iotype = UPIO_MEM32;
2211 p += 7;
2212 } else if (strncmp(p, "mmio32be,", 9) == 0) {
2213 *iotype = UPIO_MEM32BE;
2214 p += 9;
2215 } else if (strncmp(p, "mmio32native,", 13) == 0) {
2216 *iotype = IS_ENABLED(CONFIG_CPU_BIG_ENDIAN) ?
2217 UPIO_MEM32BE : UPIO_MEM32;
2218 p += 13;
2219 } else if (strncmp(p, "io,", 3) == 0) {
2220 *iotype = UPIO_PORT;
2221 p += 3;
2222 } else if (strncmp(p, "0x", 2) == 0) {
2223 *iotype = UPIO_MEM;
2224 } else {
2225 return -EINVAL;
2226 }
2227
2228 /*
2229 * Before you replace it with kstrtoull(), think about options separator
2230 * (',') it will not tolerate
2231 */
2232 *addr = simple_strtoull(p, NULL, 0);
2233 p = strchr(p, ',');
2234 if (p)
2235 p++;
2236
2237 *options = p;
2238 return 0;
2239 }
2240 EXPORT_SYMBOL_GPL(uart_parse_earlycon);
2241
2242 /**
2243 * uart_parse_options - Parse serial port baud/parity/bits/flow control.
2244 * @options: pointer to option string
2245 * @baud: pointer to an 'int' variable for the baud rate.
2246 * @parity: pointer to an 'int' variable for the parity.
2247 * @bits: pointer to an 'int' variable for the number of data bits.
2248 * @flow: pointer to an 'int' variable for the flow control character.
2249 *
2250 * uart_parse_options() decodes a string containing the serial console
2251 * options. The format of the string is <baud><parity><bits><flow>,
2252 * eg: 115200n8r
2253 */
2254 void
uart_parse_options(const char * options,int * baud,int * parity,int * bits,int * flow)2255 uart_parse_options(const char *options, int *baud, int *parity,
2256 int *bits, int *flow)
2257 {
2258 const char *s = options;
2259
2260 *baud = simple_strtoul(s, NULL, 10);
2261 while (*s >= '0' && *s <= '9')
2262 s++;
2263 if (*s)
2264 *parity = *s++;
2265 if (*s)
2266 *bits = *s++ - '0';
2267 if (*s)
2268 *flow = *s;
2269 }
2270 EXPORT_SYMBOL_GPL(uart_parse_options);
2271
2272 /**
2273 * uart_set_options - setup the serial console parameters
2274 * @port: pointer to the serial ports uart_port structure
2275 * @co: console pointer
2276 * @baud: baud rate
2277 * @parity: parity character - 'n' (none), 'o' (odd), 'e' (even)
2278 * @bits: number of data bits
2279 * @flow: flow control character - 'r' (rts)
2280 *
2281 * Locking: Caller must hold console_list_lock in order to serialize
2282 * early initialization of the serial-console lock.
2283 */
2284 int
uart_set_options(struct uart_port * port,struct console * co,int baud,int parity,int bits,int flow)2285 uart_set_options(struct uart_port *port, struct console *co,
2286 int baud, int parity, int bits, int flow)
2287 {
2288 struct ktermios termios;
2289 static struct ktermios dummy;
2290
2291 /*
2292 * Ensure that the serial-console lock is initialised early.
2293 *
2294 * Note that the console-registered check is needed because
2295 * kgdboc can call uart_set_options() for an already registered
2296 * console via tty_find_polling_driver() and uart_poll_init().
2297 */
2298 if (!uart_console_registered_locked(port) && !port->console_reinit)
2299 uart_port_spin_lock_init(port);
2300
2301 memset(&termios, 0, sizeof(struct ktermios));
2302
2303 termios.c_cflag |= CREAD | HUPCL | CLOCAL;
2304 tty_termios_encode_baud_rate(&termios, baud, baud);
2305
2306 if (bits == 7)
2307 termios.c_cflag |= CS7;
2308 else
2309 termios.c_cflag |= CS8;
2310
2311 switch (parity) {
2312 case 'o': case 'O':
2313 termios.c_cflag |= PARODD;
2314 fallthrough;
2315 case 'e': case 'E':
2316 termios.c_cflag |= PARENB;
2317 break;
2318 }
2319
2320 if (flow == 'r')
2321 termios.c_cflag |= CRTSCTS;
2322
2323 /*
2324 * some uarts on other side don't support no flow control.
2325 * So we set * DTR in host uart to make them happy
2326 */
2327 port->mctrl |= TIOCM_DTR;
2328
2329 port->ops->set_termios(port, &termios, &dummy);
2330 /*
2331 * Allow the setting of the UART parameters with a NULL console
2332 * too:
2333 */
2334 if (co) {
2335 co->cflag = termios.c_cflag;
2336 co->ispeed = termios.c_ispeed;
2337 co->ospeed = termios.c_ospeed;
2338 }
2339
2340 return 0;
2341 }
2342 EXPORT_SYMBOL_GPL(uart_set_options);
2343 #endif /* CONFIG_SERIAL_CORE_CONSOLE */
2344
2345 /**
2346 * uart_change_pm - set power state of the port
2347 *
2348 * @state: port descriptor
2349 * @pm_state: new state
2350 *
2351 * Locking: port->mutex has to be held
2352 */
uart_change_pm(struct uart_state * state,enum uart_pm_state pm_state)2353 static void uart_change_pm(struct uart_state *state,
2354 enum uart_pm_state pm_state)
2355 {
2356 struct uart_port *port = uart_port_check(state);
2357
2358 if (state->pm_state != pm_state) {
2359 if (port && port->ops->pm)
2360 port->ops->pm(port, pm_state, state->pm_state);
2361 state->pm_state = pm_state;
2362 }
2363 }
2364
2365 struct uart_match {
2366 struct uart_port *port;
2367 struct uart_driver *driver;
2368 };
2369
serial_match_port(struct device * dev,void * data)2370 static int serial_match_port(struct device *dev, void *data)
2371 {
2372 struct uart_match *match = data;
2373 struct tty_driver *tty_drv = match->driver->tty_driver;
2374 dev_t devt = MKDEV(tty_drv->major, tty_drv->minor_start) +
2375 match->port->line;
2376
2377 return dev->devt == devt; /* Actually, only one tty per port */
2378 }
2379
uart_suspend_port(struct uart_driver * drv,struct uart_port * uport)2380 int uart_suspend_port(struct uart_driver *drv, struct uart_port *uport)
2381 {
2382 struct uart_state *state = drv->state + uport->line;
2383 struct tty_port *port = &state->port;
2384 struct device *tty_dev;
2385 struct uart_match match = {uport, drv};
2386
2387 mutex_lock(&port->mutex);
2388
2389 tty_dev = device_find_child(uport->dev, &match, serial_match_port);
2390 if (tty_dev && device_may_wakeup(tty_dev)) {
2391 enable_irq_wake(uport->irq);
2392 put_device(tty_dev);
2393 mutex_unlock(&port->mutex);
2394 return 0;
2395 }
2396 put_device(tty_dev);
2397
2398 /*
2399 * Nothing to do if the console is not suspending
2400 * except stop_rx to prevent any asynchronous data
2401 * over RX line. However ensure that we will be
2402 * able to Re-start_rx later.
2403 */
2404 if (!console_suspend_enabled && uart_console(uport)) {
2405 if (uport->ops->start_rx) {
2406 spin_lock_irq(&uport->lock);
2407 uport->ops->stop_rx(uport);
2408 spin_unlock_irq(&uport->lock);
2409 }
2410 goto unlock;
2411 }
2412
2413 uport->suspended = 1;
2414
2415 if (tty_port_initialized(port)) {
2416 const struct uart_ops *ops = uport->ops;
2417 int tries;
2418 unsigned int mctrl;
2419
2420 tty_port_set_suspended(port, true);
2421 tty_port_set_initialized(port, false);
2422
2423 spin_lock_irq(&uport->lock);
2424 ops->stop_tx(uport);
2425 if (!(uport->rs485.flags & SER_RS485_ENABLED))
2426 ops->set_mctrl(uport, 0);
2427 /* save mctrl so it can be restored on resume */
2428 mctrl = uport->mctrl;
2429 uport->mctrl = 0;
2430 ops->stop_rx(uport);
2431 spin_unlock_irq(&uport->lock);
2432
2433 /*
2434 * Wait for the transmitter to empty.
2435 */
2436 for (tries = 3; !ops->tx_empty(uport) && tries; tries--)
2437 msleep(10);
2438 if (!tries)
2439 dev_err(uport->dev, "%s: Unable to drain transmitter\n",
2440 uport->name);
2441
2442 ops->shutdown(uport);
2443 uport->mctrl = mctrl;
2444 }
2445
2446 /*
2447 * Disable the console device before suspending.
2448 */
2449 if (uart_console(uport))
2450 console_stop(uport->cons);
2451
2452 uart_change_pm(state, UART_PM_STATE_OFF);
2453 unlock:
2454 mutex_unlock(&port->mutex);
2455
2456 return 0;
2457 }
2458 EXPORT_SYMBOL(uart_suspend_port);
2459
uart_resume_port(struct uart_driver * drv,struct uart_port * uport)2460 int uart_resume_port(struct uart_driver *drv, struct uart_port *uport)
2461 {
2462 struct uart_state *state = drv->state + uport->line;
2463 struct tty_port *port = &state->port;
2464 struct device *tty_dev;
2465 struct uart_match match = {uport, drv};
2466 struct ktermios termios;
2467
2468 mutex_lock(&port->mutex);
2469
2470 tty_dev = device_find_child(uport->dev, &match, serial_match_port);
2471 if (!uport->suspended && device_may_wakeup(tty_dev)) {
2472 if (irqd_is_wakeup_set(irq_get_irq_data((uport->irq))))
2473 disable_irq_wake(uport->irq);
2474 put_device(tty_dev);
2475 mutex_unlock(&port->mutex);
2476 return 0;
2477 }
2478 put_device(tty_dev);
2479 uport->suspended = 0;
2480
2481 /*
2482 * Re-enable the console device after suspending.
2483 */
2484 if (uart_console(uport)) {
2485 /*
2486 * First try to use the console cflag setting.
2487 */
2488 memset(&termios, 0, sizeof(struct ktermios));
2489 termios.c_cflag = uport->cons->cflag;
2490 termios.c_ispeed = uport->cons->ispeed;
2491 termios.c_ospeed = uport->cons->ospeed;
2492
2493 /*
2494 * If that's unset, use the tty termios setting.
2495 */
2496 if (port->tty && termios.c_cflag == 0)
2497 termios = port->tty->termios;
2498
2499 if (console_suspend_enabled)
2500 uart_change_pm(state, UART_PM_STATE_ON);
2501 uport->ops->set_termios(uport, &termios, NULL);
2502 if (!console_suspend_enabled && uport->ops->start_rx) {
2503 spin_lock_irq(&uport->lock);
2504 uport->ops->start_rx(uport);
2505 spin_unlock_irq(&uport->lock);
2506 }
2507 if (console_suspend_enabled)
2508 console_start(uport->cons);
2509 }
2510
2511 if (tty_port_suspended(port)) {
2512 const struct uart_ops *ops = uport->ops;
2513 int ret;
2514
2515 uart_change_pm(state, UART_PM_STATE_ON);
2516 spin_lock_irq(&uport->lock);
2517 if (!(uport->rs485.flags & SER_RS485_ENABLED))
2518 ops->set_mctrl(uport, 0);
2519 spin_unlock_irq(&uport->lock);
2520 if (console_suspend_enabled || !uart_console(uport)) {
2521 /* Protected by port mutex for now */
2522 struct tty_struct *tty = port->tty;
2523
2524 ret = ops->startup(uport);
2525 if (ret == 0) {
2526 if (tty)
2527 uart_change_line_settings(tty, state, NULL);
2528 uart_rs485_config(uport);
2529 spin_lock_irq(&uport->lock);
2530 if (!(uport->rs485.flags & SER_RS485_ENABLED))
2531 ops->set_mctrl(uport, uport->mctrl);
2532 ops->start_tx(uport);
2533 spin_unlock_irq(&uport->lock);
2534 tty_port_set_initialized(port, true);
2535 } else {
2536 /*
2537 * Failed to resume - maybe hardware went away?
2538 * Clear the "initialized" flag so we won't try
2539 * to call the low level drivers shutdown method.
2540 */
2541 uart_shutdown(tty, state);
2542 }
2543 }
2544
2545 tty_port_set_suspended(port, false);
2546 }
2547
2548 mutex_unlock(&port->mutex);
2549
2550 return 0;
2551 }
2552 EXPORT_SYMBOL(uart_resume_port);
2553
2554 static inline void
uart_report_port(struct uart_driver * drv,struct uart_port * port)2555 uart_report_port(struct uart_driver *drv, struct uart_port *port)
2556 {
2557 char address[64];
2558
2559 switch (port->iotype) {
2560 case UPIO_PORT:
2561 snprintf(address, sizeof(address), "I/O 0x%lx", port->iobase);
2562 break;
2563 case UPIO_HUB6:
2564 snprintf(address, sizeof(address),
2565 "I/O 0x%lx offset 0x%x", port->iobase, port->hub6);
2566 break;
2567 case UPIO_MEM:
2568 case UPIO_MEM16:
2569 case UPIO_MEM32:
2570 case UPIO_MEM32BE:
2571 case UPIO_AU:
2572 case UPIO_TSI:
2573 snprintf(address, sizeof(address),
2574 "MMIO 0x%llx", (unsigned long long)port->mapbase);
2575 break;
2576 default:
2577 strscpy(address, "*unknown*", sizeof(address));
2578 break;
2579 }
2580
2581 pr_info("%s%s%s at %s (irq = %d, base_baud = %d) is a %s\n",
2582 port->dev ? dev_name(port->dev) : "",
2583 port->dev ? ": " : "",
2584 port->name,
2585 address, port->irq, port->uartclk / 16, uart_type(port));
2586
2587 /* The magic multiplier feature is a bit obscure, so report it too. */
2588 if (port->flags & UPF_MAGIC_MULTIPLIER)
2589 pr_info("%s%s%s extra baud rates supported: %d, %d",
2590 port->dev ? dev_name(port->dev) : "",
2591 port->dev ? ": " : "",
2592 port->name,
2593 port->uartclk / 8, port->uartclk / 4);
2594 }
2595
2596 static void
uart_configure_port(struct uart_driver * drv,struct uart_state * state,struct uart_port * port)2597 uart_configure_port(struct uart_driver *drv, struct uart_state *state,
2598 struct uart_port *port)
2599 {
2600 unsigned int flags;
2601
2602 /*
2603 * If there isn't a port here, don't do anything further.
2604 */
2605 if (!port->iobase && !port->mapbase && !port->membase)
2606 return;
2607
2608 /*
2609 * Now do the auto configuration stuff. Note that config_port
2610 * is expected to claim the resources and map the port for us.
2611 */
2612 flags = 0;
2613 if (port->flags & UPF_AUTO_IRQ)
2614 flags |= UART_CONFIG_IRQ;
2615 if (port->flags & UPF_BOOT_AUTOCONF) {
2616 if (!(port->flags & UPF_FIXED_TYPE)) {
2617 port->type = PORT_UNKNOWN;
2618 flags |= UART_CONFIG_TYPE;
2619 }
2620 /* Synchronize with possible boot console. */
2621 if (uart_console(port))
2622 console_lock();
2623 port->ops->config_port(port, flags);
2624 if (uart_console(port))
2625 console_unlock();
2626 }
2627
2628 if (port->type != PORT_UNKNOWN) {
2629 unsigned long flags;
2630
2631 uart_report_port(drv, port);
2632
2633 /* Synchronize with possible boot console. */
2634 if (uart_console(port))
2635 console_lock();
2636
2637 /* Power up port for set_mctrl() */
2638 uart_change_pm(state, UART_PM_STATE_ON);
2639
2640 /*
2641 * Ensure that the modem control lines are de-activated.
2642 * keep the DTR setting that is set in uart_set_options()
2643 * We probably don't need a spinlock around this, but
2644 */
2645 spin_lock_irqsave(&port->lock, flags);
2646 port->mctrl &= TIOCM_DTR;
2647 if (!(port->rs485.flags & SER_RS485_ENABLED))
2648 port->ops->set_mctrl(port, port->mctrl);
2649 spin_unlock_irqrestore(&port->lock, flags);
2650
2651 uart_rs485_config(port);
2652
2653 if (uart_console(port))
2654 console_unlock();
2655
2656 /*
2657 * If this driver supports console, and it hasn't been
2658 * successfully registered yet, try to re-register it.
2659 * It may be that the port was not available.
2660 */
2661 if (port->cons && !console_is_registered(port->cons))
2662 register_console(port->cons);
2663
2664 /*
2665 * Power down all ports by default, except the
2666 * console if we have one.
2667 */
2668 if (!uart_console(port))
2669 uart_change_pm(state, UART_PM_STATE_OFF);
2670 }
2671 }
2672
2673 #ifdef CONFIG_CONSOLE_POLL
2674
uart_poll_init(struct tty_driver * driver,int line,char * options)2675 static int uart_poll_init(struct tty_driver *driver, int line, char *options)
2676 {
2677 struct uart_driver *drv = driver->driver_state;
2678 struct uart_state *state = drv->state + line;
2679 enum uart_pm_state pm_state;
2680 struct tty_port *tport;
2681 struct uart_port *port;
2682 int baud = 9600;
2683 int bits = 8;
2684 int parity = 'n';
2685 int flow = 'n';
2686 int ret = 0;
2687
2688 tport = &state->port;
2689 mutex_lock(&tport->mutex);
2690
2691 port = uart_port_check(state);
2692 if (!port || !(port->ops->poll_get_char && port->ops->poll_put_char)) {
2693 ret = -1;
2694 goto out;
2695 }
2696
2697 pm_state = state->pm_state;
2698 uart_change_pm(state, UART_PM_STATE_ON);
2699
2700 if (port->ops->poll_init) {
2701 /*
2702 * We don't set initialized as we only initialized the hw,
2703 * e.g. state->xmit is still uninitialized.
2704 */
2705 if (!tty_port_initialized(tport))
2706 ret = port->ops->poll_init(port);
2707 }
2708
2709 if (!ret && options) {
2710 uart_parse_options(options, &baud, &parity, &bits, &flow);
2711 console_list_lock();
2712 ret = uart_set_options(port, NULL, baud, parity, bits, flow);
2713 console_list_unlock();
2714 }
2715 out:
2716 if (ret)
2717 uart_change_pm(state, pm_state);
2718 mutex_unlock(&tport->mutex);
2719 return ret;
2720 }
2721
uart_poll_get_char(struct tty_driver * driver,int line)2722 static int uart_poll_get_char(struct tty_driver *driver, int line)
2723 {
2724 struct uart_driver *drv = driver->driver_state;
2725 struct uart_state *state = drv->state + line;
2726 struct uart_port *port;
2727 int ret = -1;
2728
2729 port = uart_port_ref(state);
2730 if (port) {
2731 ret = port->ops->poll_get_char(port);
2732 uart_port_deref(port);
2733 }
2734
2735 return ret;
2736 }
2737
uart_poll_put_char(struct tty_driver * driver,int line,char ch)2738 static void uart_poll_put_char(struct tty_driver *driver, int line, char ch)
2739 {
2740 struct uart_driver *drv = driver->driver_state;
2741 struct uart_state *state = drv->state + line;
2742 struct uart_port *port;
2743
2744 port = uart_port_ref(state);
2745 if (!port)
2746 return;
2747
2748 if (ch == '\n')
2749 port->ops->poll_put_char(port, '\r');
2750 port->ops->poll_put_char(port, ch);
2751 uart_port_deref(port);
2752 }
2753 #endif
2754
2755 static const struct tty_operations uart_ops = {
2756 .install = uart_install,
2757 .open = uart_open,
2758 .close = uart_close,
2759 .write = uart_write,
2760 .put_char = uart_put_char,
2761 .flush_chars = uart_flush_chars,
2762 .write_room = uart_write_room,
2763 .chars_in_buffer= uart_chars_in_buffer,
2764 .flush_buffer = uart_flush_buffer,
2765 .ioctl = uart_ioctl,
2766 .throttle = uart_throttle,
2767 .unthrottle = uart_unthrottle,
2768 .send_xchar = uart_send_xchar,
2769 .set_termios = uart_set_termios,
2770 .set_ldisc = uart_set_ldisc,
2771 .stop = uart_stop,
2772 .start = uart_start,
2773 .hangup = uart_hangup,
2774 .break_ctl = uart_break_ctl,
2775 .wait_until_sent= uart_wait_until_sent,
2776 #ifdef CONFIG_PROC_FS
2777 .proc_show = uart_proc_show,
2778 #endif
2779 .tiocmget = uart_tiocmget,
2780 .tiocmset = uart_tiocmset,
2781 .set_serial = uart_set_info_user,
2782 .get_serial = uart_get_info_user,
2783 .get_icount = uart_get_icount,
2784 #ifdef CONFIG_CONSOLE_POLL
2785 .poll_init = uart_poll_init,
2786 .poll_get_char = uart_poll_get_char,
2787 .poll_put_char = uart_poll_put_char,
2788 #endif
2789 };
2790
2791 static const struct tty_port_operations uart_port_ops = {
2792 .carrier_raised = uart_carrier_raised,
2793 .dtr_rts = uart_dtr_rts,
2794 .activate = uart_port_activate,
2795 .shutdown = uart_tty_port_shutdown,
2796 };
2797
2798 /**
2799 * uart_register_driver - register a driver with the uart core layer
2800 * @drv: low level driver structure
2801 *
2802 * Register a uart driver with the core driver. We in turn register with the
2803 * tty layer, and initialise the core driver per-port state.
2804 *
2805 * We have a proc file in /proc/tty/driver which is named after the normal
2806 * driver.
2807 *
2808 * @drv->port should be %NULL, and the per-port structures should be registered
2809 * using uart_add_one_port() after this call has succeeded.
2810 *
2811 * Locking: none, Interrupts: enabled
2812 */
uart_register_driver(struct uart_driver * drv)2813 int uart_register_driver(struct uart_driver *drv)
2814 {
2815 struct tty_driver *normal;
2816 int i, retval = -ENOMEM;
2817
2818 BUG_ON(drv->state);
2819
2820 /*
2821 * Maybe we should be using a slab cache for this, especially if
2822 * we have a large number of ports to handle.
2823 */
2824 drv->state = kcalloc(drv->nr, sizeof(struct uart_state), GFP_KERNEL);
2825 if (!drv->state)
2826 goto out;
2827
2828 normal = tty_alloc_driver(drv->nr, TTY_DRIVER_REAL_RAW |
2829 TTY_DRIVER_DYNAMIC_DEV);
2830 if (IS_ERR(normal)) {
2831 retval = PTR_ERR(normal);
2832 goto out_kfree;
2833 }
2834
2835 drv->tty_driver = normal;
2836
2837 normal->driver_name = drv->driver_name;
2838 normal->name = drv->dev_name;
2839 normal->major = drv->major;
2840 normal->minor_start = drv->minor;
2841 normal->type = TTY_DRIVER_TYPE_SERIAL;
2842 normal->subtype = SERIAL_TYPE_NORMAL;
2843 normal->init_termios = tty_std_termios;
2844 normal->init_termios.c_cflag = B9600 | CS8 | CREAD | HUPCL | CLOCAL;
2845 normal->init_termios.c_ispeed = normal->init_termios.c_ospeed = 9600;
2846 normal->driver_state = drv;
2847 tty_set_operations(normal, &uart_ops);
2848
2849 /*
2850 * Initialise the UART state(s).
2851 */
2852 for (i = 0; i < drv->nr; i++) {
2853 struct uart_state *state = drv->state + i;
2854 struct tty_port *port = &state->port;
2855
2856 tty_port_init(port);
2857 port->ops = &uart_port_ops;
2858 }
2859
2860 retval = tty_register_driver(normal);
2861 if (retval >= 0)
2862 return retval;
2863
2864 for (i = 0; i < drv->nr; i++)
2865 tty_port_destroy(&drv->state[i].port);
2866 tty_driver_kref_put(normal);
2867 out_kfree:
2868 kfree(drv->state);
2869 out:
2870 return retval;
2871 }
2872 EXPORT_SYMBOL(uart_register_driver);
2873
2874 /**
2875 * uart_unregister_driver - remove a driver from the uart core layer
2876 * @drv: low level driver structure
2877 *
2878 * Remove all references to a driver from the core driver. The low level
2879 * driver must have removed all its ports via the uart_remove_one_port() if it
2880 * registered them with uart_add_one_port(). (I.e. @drv->port is %NULL.)
2881 *
2882 * Locking: none, Interrupts: enabled
2883 */
uart_unregister_driver(struct uart_driver * drv)2884 void uart_unregister_driver(struct uart_driver *drv)
2885 {
2886 struct tty_driver *p = drv->tty_driver;
2887 unsigned int i;
2888
2889 tty_unregister_driver(p);
2890 tty_driver_kref_put(p);
2891 for (i = 0; i < drv->nr; i++)
2892 tty_port_destroy(&drv->state[i].port);
2893 kfree(drv->state);
2894 drv->state = NULL;
2895 drv->tty_driver = NULL;
2896 }
2897 EXPORT_SYMBOL(uart_unregister_driver);
2898
uart_console_device(struct console * co,int * index)2899 struct tty_driver *uart_console_device(struct console *co, int *index)
2900 {
2901 struct uart_driver *p = co->data;
2902 *index = co->index;
2903 return p->tty_driver;
2904 }
2905 EXPORT_SYMBOL_GPL(uart_console_device);
2906
uartclk_show(struct device * dev,struct device_attribute * attr,char * buf)2907 static ssize_t uartclk_show(struct device *dev,
2908 struct device_attribute *attr, char *buf)
2909 {
2910 struct serial_struct tmp;
2911 struct tty_port *port = dev_get_drvdata(dev);
2912
2913 uart_get_info(port, &tmp);
2914 return sprintf(buf, "%d\n", tmp.baud_base * 16);
2915 }
2916
type_show(struct device * dev,struct device_attribute * attr,char * buf)2917 static ssize_t type_show(struct device *dev,
2918 struct device_attribute *attr, char *buf)
2919 {
2920 struct serial_struct tmp;
2921 struct tty_port *port = dev_get_drvdata(dev);
2922
2923 uart_get_info(port, &tmp);
2924 return sprintf(buf, "%d\n", tmp.type);
2925 }
2926
line_show(struct device * dev,struct device_attribute * attr,char * buf)2927 static ssize_t line_show(struct device *dev,
2928 struct device_attribute *attr, char *buf)
2929 {
2930 struct serial_struct tmp;
2931 struct tty_port *port = dev_get_drvdata(dev);
2932
2933 uart_get_info(port, &tmp);
2934 return sprintf(buf, "%d\n", tmp.line);
2935 }
2936
port_show(struct device * dev,struct device_attribute * attr,char * buf)2937 static ssize_t port_show(struct device *dev,
2938 struct device_attribute *attr, char *buf)
2939 {
2940 struct serial_struct tmp;
2941 struct tty_port *port = dev_get_drvdata(dev);
2942 unsigned long ioaddr;
2943
2944 uart_get_info(port, &tmp);
2945 ioaddr = tmp.port;
2946 if (HIGH_BITS_OFFSET)
2947 ioaddr |= (unsigned long)tmp.port_high << HIGH_BITS_OFFSET;
2948 return sprintf(buf, "0x%lX\n", ioaddr);
2949 }
2950
irq_show(struct device * dev,struct device_attribute * attr,char * buf)2951 static ssize_t irq_show(struct device *dev,
2952 struct device_attribute *attr, char *buf)
2953 {
2954 struct serial_struct tmp;
2955 struct tty_port *port = dev_get_drvdata(dev);
2956
2957 uart_get_info(port, &tmp);
2958 return sprintf(buf, "%d\n", tmp.irq);
2959 }
2960
flags_show(struct device * dev,struct device_attribute * attr,char * buf)2961 static ssize_t flags_show(struct device *dev,
2962 struct device_attribute *attr, char *buf)
2963 {
2964 struct serial_struct tmp;
2965 struct tty_port *port = dev_get_drvdata(dev);
2966
2967 uart_get_info(port, &tmp);
2968 return sprintf(buf, "0x%X\n", tmp.flags);
2969 }
2970
xmit_fifo_size_show(struct device * dev,struct device_attribute * attr,char * buf)2971 static ssize_t xmit_fifo_size_show(struct device *dev,
2972 struct device_attribute *attr, char *buf)
2973 {
2974 struct serial_struct tmp;
2975 struct tty_port *port = dev_get_drvdata(dev);
2976
2977 uart_get_info(port, &tmp);
2978 return sprintf(buf, "%d\n", tmp.xmit_fifo_size);
2979 }
2980
close_delay_show(struct device * dev,struct device_attribute * attr,char * buf)2981 static ssize_t close_delay_show(struct device *dev,
2982 struct device_attribute *attr, char *buf)
2983 {
2984 struct serial_struct tmp;
2985 struct tty_port *port = dev_get_drvdata(dev);
2986
2987 uart_get_info(port, &tmp);
2988 return sprintf(buf, "%d\n", tmp.close_delay);
2989 }
2990
closing_wait_show(struct device * dev,struct device_attribute * attr,char * buf)2991 static ssize_t closing_wait_show(struct device *dev,
2992 struct device_attribute *attr, char *buf)
2993 {
2994 struct serial_struct tmp;
2995 struct tty_port *port = dev_get_drvdata(dev);
2996
2997 uart_get_info(port, &tmp);
2998 return sprintf(buf, "%d\n", tmp.closing_wait);
2999 }
3000
custom_divisor_show(struct device * dev,struct device_attribute * attr,char * buf)3001 static ssize_t custom_divisor_show(struct device *dev,
3002 struct device_attribute *attr, char *buf)
3003 {
3004 struct serial_struct tmp;
3005 struct tty_port *port = dev_get_drvdata(dev);
3006
3007 uart_get_info(port, &tmp);
3008 return sprintf(buf, "%d\n", tmp.custom_divisor);
3009 }
3010
io_type_show(struct device * dev,struct device_attribute * attr,char * buf)3011 static ssize_t io_type_show(struct device *dev,
3012 struct device_attribute *attr, char *buf)
3013 {
3014 struct serial_struct tmp;
3015 struct tty_port *port = dev_get_drvdata(dev);
3016
3017 uart_get_info(port, &tmp);
3018 return sprintf(buf, "%d\n", tmp.io_type);
3019 }
3020
iomem_base_show(struct device * dev,struct device_attribute * attr,char * buf)3021 static ssize_t iomem_base_show(struct device *dev,
3022 struct device_attribute *attr, char *buf)
3023 {
3024 struct serial_struct tmp;
3025 struct tty_port *port = dev_get_drvdata(dev);
3026
3027 uart_get_info(port, &tmp);
3028 return sprintf(buf, "0x%lX\n", (unsigned long)tmp.iomem_base);
3029 }
3030
iomem_reg_shift_show(struct device * dev,struct device_attribute * attr,char * buf)3031 static ssize_t iomem_reg_shift_show(struct device *dev,
3032 struct device_attribute *attr, char *buf)
3033 {
3034 struct serial_struct tmp;
3035 struct tty_port *port = dev_get_drvdata(dev);
3036
3037 uart_get_info(port, &tmp);
3038 return sprintf(buf, "%d\n", tmp.iomem_reg_shift);
3039 }
3040
console_show(struct device * dev,struct device_attribute * attr,char * buf)3041 static ssize_t console_show(struct device *dev,
3042 struct device_attribute *attr, char *buf)
3043 {
3044 struct tty_port *port = dev_get_drvdata(dev);
3045 struct uart_state *state = container_of(port, struct uart_state, port);
3046 struct uart_port *uport;
3047 bool console = false;
3048
3049 mutex_lock(&port->mutex);
3050 uport = uart_port_check(state);
3051 if (uport)
3052 console = uart_console_registered(uport);
3053 mutex_unlock(&port->mutex);
3054
3055 return sprintf(buf, "%c\n", console ? 'Y' : 'N');
3056 }
3057
console_store(struct device * dev,struct device_attribute * attr,const char * buf,size_t count)3058 static ssize_t console_store(struct device *dev,
3059 struct device_attribute *attr, const char *buf, size_t count)
3060 {
3061 struct tty_port *port = dev_get_drvdata(dev);
3062 struct uart_state *state = container_of(port, struct uart_state, port);
3063 struct uart_port *uport;
3064 bool oldconsole, newconsole;
3065 int ret;
3066
3067 ret = kstrtobool(buf, &newconsole);
3068 if (ret)
3069 return ret;
3070
3071 mutex_lock(&port->mutex);
3072 uport = uart_port_check(state);
3073 if (uport) {
3074 oldconsole = uart_console_registered(uport);
3075 if (oldconsole && !newconsole) {
3076 ret = unregister_console(uport->cons);
3077 } else if (!oldconsole && newconsole) {
3078 if (uart_console(uport)) {
3079 uport->console_reinit = 1;
3080 register_console(uport->cons);
3081 } else {
3082 ret = -ENOENT;
3083 }
3084 }
3085 } else {
3086 ret = -ENXIO;
3087 }
3088 mutex_unlock(&port->mutex);
3089
3090 return ret < 0 ? ret : count;
3091 }
3092
3093 static DEVICE_ATTR_RO(uartclk);
3094 static DEVICE_ATTR_RO(type);
3095 static DEVICE_ATTR_RO(line);
3096 static DEVICE_ATTR_RO(port);
3097 static DEVICE_ATTR_RO(irq);
3098 static DEVICE_ATTR_RO(flags);
3099 static DEVICE_ATTR_RO(xmit_fifo_size);
3100 static DEVICE_ATTR_RO(close_delay);
3101 static DEVICE_ATTR_RO(closing_wait);
3102 static DEVICE_ATTR_RO(custom_divisor);
3103 static DEVICE_ATTR_RO(io_type);
3104 static DEVICE_ATTR_RO(iomem_base);
3105 static DEVICE_ATTR_RO(iomem_reg_shift);
3106 static DEVICE_ATTR_RW(console);
3107
3108 static struct attribute *tty_dev_attrs[] = {
3109 &dev_attr_uartclk.attr,
3110 &dev_attr_type.attr,
3111 &dev_attr_line.attr,
3112 &dev_attr_port.attr,
3113 &dev_attr_irq.attr,
3114 &dev_attr_flags.attr,
3115 &dev_attr_xmit_fifo_size.attr,
3116 &dev_attr_close_delay.attr,
3117 &dev_attr_closing_wait.attr,
3118 &dev_attr_custom_divisor.attr,
3119 &dev_attr_io_type.attr,
3120 &dev_attr_iomem_base.attr,
3121 &dev_attr_iomem_reg_shift.attr,
3122 &dev_attr_console.attr,
3123 NULL
3124 };
3125
3126 static const struct attribute_group tty_dev_attr_group = {
3127 .attrs = tty_dev_attrs,
3128 };
3129
3130 /**
3131 * serial_core_add_one_port - attach a driver-defined port structure
3132 * @drv: pointer to the uart low level driver structure for this port
3133 * @uport: uart port structure to use for this port.
3134 *
3135 * Context: task context, might sleep
3136 *
3137 * This allows the driver @drv to register its own uart_port structure with the
3138 * core driver. The main purpose is to allow the low level uart drivers to
3139 * expand uart_port, rather than having yet more levels of structures.
3140 * Caller must hold port_mutex.
3141 */
serial_core_add_one_port(struct uart_driver * drv,struct uart_port * uport)3142 static int serial_core_add_one_port(struct uart_driver *drv, struct uart_port *uport)
3143 {
3144 struct uart_state *state;
3145 struct tty_port *port;
3146 int ret = 0;
3147 struct device *tty_dev;
3148 int num_groups;
3149
3150 if (uport->line >= drv->nr)
3151 return -EINVAL;
3152
3153 state = drv->state + uport->line;
3154 port = &state->port;
3155
3156 mutex_lock(&port->mutex);
3157 if (state->uart_port) {
3158 ret = -EINVAL;
3159 goto out;
3160 }
3161
3162 /* Link the port to the driver state table and vice versa */
3163 atomic_set(&state->refcount, 1);
3164 init_waitqueue_head(&state->remove_wait);
3165 state->uart_port = uport;
3166 uport->state = state;
3167
3168 state->pm_state = UART_PM_STATE_UNDEFINED;
3169 uport->cons = drv->cons;
3170 uport->minor = drv->tty_driver->minor_start + uport->line;
3171 uport->name = kasprintf(GFP_KERNEL, "%s%d", drv->dev_name,
3172 drv->tty_driver->name_base + uport->line);
3173 if (!uport->name) {
3174 ret = -ENOMEM;
3175 goto out;
3176 }
3177
3178 /*
3179 * If this port is in use as a console then the spinlock is already
3180 * initialised.
3181 */
3182 if (!uart_console_registered(uport))
3183 uart_port_spin_lock_init(uport);
3184
3185 if (uport->cons && uport->dev)
3186 of_console_check(uport->dev->of_node, uport->cons->name, uport->line);
3187
3188 tty_port_link_device(port, drv->tty_driver, uport->line);
3189 uart_configure_port(drv, state, uport);
3190
3191 port->console = uart_console(uport);
3192
3193 num_groups = 2;
3194 if (uport->attr_group)
3195 num_groups++;
3196
3197 uport->tty_groups = kcalloc(num_groups, sizeof(*uport->tty_groups),
3198 GFP_KERNEL);
3199 if (!uport->tty_groups) {
3200 ret = -ENOMEM;
3201 goto out;
3202 }
3203 uport->tty_groups[0] = &tty_dev_attr_group;
3204 if (uport->attr_group)
3205 uport->tty_groups[1] = uport->attr_group;
3206
3207 /*
3208 * Register the port whether it's detected or not. This allows
3209 * setserial to be used to alter this port's parameters.
3210 */
3211 tty_dev = tty_port_register_device_attr_serdev(port, drv->tty_driver,
3212 uport->line, uport->dev, port, uport->tty_groups);
3213 if (!IS_ERR(tty_dev)) {
3214 device_set_wakeup_capable(tty_dev, 1);
3215 } else {
3216 dev_err(uport->dev, "Cannot register tty device on line %d\n",
3217 uport->line);
3218 }
3219
3220 out:
3221 mutex_unlock(&port->mutex);
3222
3223 return ret;
3224 }
3225
3226 /**
3227 * serial_core_remove_one_port - detach a driver defined port structure
3228 * @drv: pointer to the uart low level driver structure for this port
3229 * @uport: uart port structure for this port
3230 *
3231 * Context: task context, might sleep
3232 *
3233 * This unhooks (and hangs up) the specified port structure from the core
3234 * driver. No further calls will be made to the low-level code for this port.
3235 * Caller must hold port_mutex.
3236 */
serial_core_remove_one_port(struct uart_driver * drv,struct uart_port * uport)3237 static void serial_core_remove_one_port(struct uart_driver *drv,
3238 struct uart_port *uport)
3239 {
3240 struct uart_state *state = drv->state + uport->line;
3241 struct tty_port *port = &state->port;
3242 struct uart_port *uart_port;
3243 struct tty_struct *tty;
3244
3245 mutex_lock(&port->mutex);
3246 uart_port = uart_port_check(state);
3247 if (uart_port != uport)
3248 dev_alert(uport->dev, "Removing wrong port: %p != %p\n",
3249 uart_port, uport);
3250
3251 if (!uart_port) {
3252 mutex_unlock(&port->mutex);
3253 return;
3254 }
3255 mutex_unlock(&port->mutex);
3256
3257 /*
3258 * Remove the devices from the tty layer
3259 */
3260 tty_port_unregister_device(port, drv->tty_driver, uport->line);
3261
3262 tty = tty_port_tty_get(port);
3263 if (tty) {
3264 tty_vhangup(port->tty);
3265 tty_kref_put(tty);
3266 }
3267
3268 /*
3269 * If the port is used as a console, unregister it
3270 */
3271 if (uart_console(uport))
3272 unregister_console(uport->cons);
3273
3274 /*
3275 * Free the port IO and memory resources, if any.
3276 */
3277 if (uport->type != PORT_UNKNOWN && uport->ops->release_port)
3278 uport->ops->release_port(uport);
3279 kfree(uport->tty_groups);
3280 kfree(uport->name);
3281
3282 /*
3283 * Indicate that there isn't a port here anymore.
3284 */
3285 uport->type = PORT_UNKNOWN;
3286 uport->port_dev = NULL;
3287
3288 mutex_lock(&port->mutex);
3289 WARN_ON(atomic_dec_return(&state->refcount) < 0);
3290 wait_event(state->remove_wait, !atomic_read(&state->refcount));
3291 state->uart_port = NULL;
3292 mutex_unlock(&port->mutex);
3293 }
3294
3295 /**
3296 * uart_match_port - are the two ports equivalent?
3297 * @port1: first port
3298 * @port2: second port
3299 *
3300 * This utility function can be used to determine whether two uart_port
3301 * structures describe the same port.
3302 */
uart_match_port(const struct uart_port * port1,const struct uart_port * port2)3303 bool uart_match_port(const struct uart_port *port1,
3304 const struct uart_port *port2)
3305 {
3306 if (port1->iotype != port2->iotype)
3307 return false;
3308
3309 switch (port1->iotype) {
3310 case UPIO_PORT:
3311 return port1->iobase == port2->iobase;
3312 case UPIO_HUB6:
3313 return port1->iobase == port2->iobase &&
3314 port1->hub6 == port2->hub6;
3315 case UPIO_MEM:
3316 case UPIO_MEM16:
3317 case UPIO_MEM32:
3318 case UPIO_MEM32BE:
3319 case UPIO_AU:
3320 case UPIO_TSI:
3321 return port1->mapbase == port2->mapbase;
3322 }
3323
3324 return false;
3325 }
3326 EXPORT_SYMBOL(uart_match_port);
3327
3328 static struct serial_ctrl_device *
serial_core_get_ctrl_dev(struct serial_port_device * port_dev)3329 serial_core_get_ctrl_dev(struct serial_port_device *port_dev)
3330 {
3331 struct device *dev = &port_dev->dev;
3332
3333 return to_serial_base_ctrl_device(dev->parent);
3334 }
3335
3336 /*
3337 * Find a registered serial core controller device if one exists. Returns
3338 * the first device matching the ctrl_id. Caller must hold port_mutex.
3339 */
serial_core_ctrl_find(struct uart_driver * drv,struct device * phys_dev,int ctrl_id)3340 static struct serial_ctrl_device *serial_core_ctrl_find(struct uart_driver *drv,
3341 struct device *phys_dev,
3342 int ctrl_id)
3343 {
3344 struct uart_state *state;
3345 int i;
3346
3347 lockdep_assert_held(&port_mutex);
3348
3349 for (i = 0; i < drv->nr; i++) {
3350 state = drv->state + i;
3351 if (!state->uart_port || !state->uart_port->port_dev)
3352 continue;
3353
3354 if (state->uart_port->dev == phys_dev &&
3355 state->uart_port->ctrl_id == ctrl_id)
3356 return serial_core_get_ctrl_dev(state->uart_port->port_dev);
3357 }
3358
3359 return NULL;
3360 }
3361
serial_core_ctrl_device_add(struct uart_port * port)3362 static struct serial_ctrl_device *serial_core_ctrl_device_add(struct uart_port *port)
3363 {
3364 return serial_base_ctrl_add(port, port->dev);
3365 }
3366
serial_core_port_device_add(struct serial_ctrl_device * ctrl_dev,struct uart_port * port)3367 static int serial_core_port_device_add(struct serial_ctrl_device *ctrl_dev,
3368 struct uart_port *port)
3369 {
3370 struct serial_port_device *port_dev;
3371
3372 port_dev = serial_base_port_add(port, ctrl_dev);
3373 if (IS_ERR(port_dev))
3374 return PTR_ERR(port_dev);
3375
3376 port->port_dev = port_dev;
3377
3378 return 0;
3379 }
3380
3381 /*
3382 * Initialize a serial core port device, and a controller device if needed.
3383 */
serial_core_register_port(struct uart_driver * drv,struct uart_port * port)3384 int serial_core_register_port(struct uart_driver *drv, struct uart_port *port)
3385 {
3386 struct serial_ctrl_device *ctrl_dev, *new_ctrl_dev = NULL;
3387 int ret;
3388
3389 mutex_lock(&port_mutex);
3390
3391 /*
3392 * Prevent serial_port_runtime_resume() from trying to use the port
3393 * until serial_core_add_one_port() has completed
3394 */
3395 port->flags |= UPF_DEAD;
3396
3397 /* Inititalize a serial core controller device if needed */
3398 ctrl_dev = serial_core_ctrl_find(drv, port->dev, port->ctrl_id);
3399 if (!ctrl_dev) {
3400 new_ctrl_dev = serial_core_ctrl_device_add(port);
3401 if (IS_ERR(new_ctrl_dev)) {
3402 ret = PTR_ERR(new_ctrl_dev);
3403 goto err_unlock;
3404 }
3405 ctrl_dev = new_ctrl_dev;
3406 }
3407
3408 /*
3409 * Initialize a serial core port device. Tag the port dead to prevent
3410 * serial_port_runtime_resume() trying to do anything until port has
3411 * been registered. It gets cleared by serial_core_add_one_port().
3412 */
3413 ret = serial_core_port_device_add(ctrl_dev, port);
3414 if (ret)
3415 goto err_unregister_ctrl_dev;
3416
3417 ret = serial_core_add_one_port(drv, port);
3418 if (ret)
3419 goto err_unregister_port_dev;
3420
3421 port->flags &= ~UPF_DEAD;
3422
3423 mutex_unlock(&port_mutex);
3424
3425 return 0;
3426
3427 err_unregister_port_dev:
3428 serial_base_port_device_remove(port->port_dev);
3429
3430 err_unregister_ctrl_dev:
3431 serial_base_ctrl_device_remove(new_ctrl_dev);
3432
3433 err_unlock:
3434 mutex_unlock(&port_mutex);
3435
3436 return ret;
3437 }
3438
3439 /*
3440 * Removes a serial core port device, and the related serial core controller
3441 * device if the last instance.
3442 */
serial_core_unregister_port(struct uart_driver * drv,struct uart_port * port)3443 void serial_core_unregister_port(struct uart_driver *drv, struct uart_port *port)
3444 {
3445 struct device *phys_dev = port->dev;
3446 struct serial_port_device *port_dev = port->port_dev;
3447 struct serial_ctrl_device *ctrl_dev = serial_core_get_ctrl_dev(port_dev);
3448 int ctrl_id = port->ctrl_id;
3449
3450 mutex_lock(&port_mutex);
3451
3452 port->flags |= UPF_DEAD;
3453
3454 serial_core_remove_one_port(drv, port);
3455
3456 /* Note that struct uart_port *port is no longer valid at this point */
3457 serial_base_port_device_remove(port_dev);
3458
3459 /* Drop the serial core controller device if no ports are using it */
3460 if (!serial_core_ctrl_find(drv, phys_dev, ctrl_id))
3461 serial_base_ctrl_device_remove(ctrl_dev);
3462
3463 mutex_unlock(&port_mutex);
3464 }
3465
3466 /**
3467 * uart_handle_dcd_change - handle a change of carrier detect state
3468 * @uport: uart_port structure for the open port
3469 * @active: new carrier detect status
3470 *
3471 * Caller must hold uport->lock.
3472 */
uart_handle_dcd_change(struct uart_port * uport,bool active)3473 void uart_handle_dcd_change(struct uart_port *uport, bool active)
3474 {
3475 struct tty_port *port = &uport->state->port;
3476 struct tty_struct *tty = port->tty;
3477 struct tty_ldisc *ld;
3478
3479 lockdep_assert_held_once(&uport->lock);
3480
3481 if (tty) {
3482 ld = tty_ldisc_ref(tty);
3483 if (ld) {
3484 if (ld->ops->dcd_change)
3485 ld->ops->dcd_change(tty, active);
3486 tty_ldisc_deref(ld);
3487 }
3488 }
3489
3490 uport->icount.dcd++;
3491
3492 if (uart_dcd_enabled(uport)) {
3493 if (active)
3494 wake_up_interruptible(&port->open_wait);
3495 else if (tty)
3496 tty_hangup(tty);
3497 }
3498 }
3499 EXPORT_SYMBOL_GPL(uart_handle_dcd_change);
3500
3501 /**
3502 * uart_handle_cts_change - handle a change of clear-to-send state
3503 * @uport: uart_port structure for the open port
3504 * @active: new clear-to-send status
3505 *
3506 * Caller must hold uport->lock.
3507 */
uart_handle_cts_change(struct uart_port * uport,bool active)3508 void uart_handle_cts_change(struct uart_port *uport, bool active)
3509 {
3510 lockdep_assert_held_once(&uport->lock);
3511
3512 uport->icount.cts++;
3513
3514 if (uart_softcts_mode(uport)) {
3515 if (uport->hw_stopped) {
3516 if (active) {
3517 uport->hw_stopped = false;
3518 uport->ops->start_tx(uport);
3519 uart_write_wakeup(uport);
3520 }
3521 } else {
3522 if (!active) {
3523 uport->hw_stopped = true;
3524 uport->ops->stop_tx(uport);
3525 }
3526 }
3527
3528 }
3529 }
3530 EXPORT_SYMBOL_GPL(uart_handle_cts_change);
3531
3532 /**
3533 * uart_insert_char - push a char to the uart layer
3534 *
3535 * User is responsible to call tty_flip_buffer_push when they are done with
3536 * insertion.
3537 *
3538 * @port: corresponding port
3539 * @status: state of the serial port RX buffer (LSR for 8250)
3540 * @overrun: mask of overrun bits in @status
3541 * @ch: character to push
3542 * @flag: flag for the character (see TTY_NORMAL and friends)
3543 */
uart_insert_char(struct uart_port * port,unsigned int status,unsigned int overrun,u8 ch,u8 flag)3544 void uart_insert_char(struct uart_port *port, unsigned int status,
3545 unsigned int overrun, u8 ch, u8 flag)
3546 {
3547 struct tty_port *tport = &port->state->port;
3548
3549 if ((status & port->ignore_status_mask & ~overrun) == 0)
3550 if (tty_insert_flip_char(tport, ch, flag) == 0)
3551 ++port->icount.buf_overrun;
3552
3553 /*
3554 * Overrun is special. Since it's reported immediately,
3555 * it doesn't affect the current character.
3556 */
3557 if (status & ~port->ignore_status_mask & overrun)
3558 if (tty_insert_flip_char(tport, 0, TTY_OVERRUN) == 0)
3559 ++port->icount.buf_overrun;
3560 }
3561 EXPORT_SYMBOL_GPL(uart_insert_char);
3562
3563 #ifdef CONFIG_MAGIC_SYSRQ_SERIAL
3564 static const u8 sysrq_toggle_seq[] = CONFIG_MAGIC_SYSRQ_SERIAL_SEQUENCE;
3565
uart_sysrq_on(struct work_struct * w)3566 static void uart_sysrq_on(struct work_struct *w)
3567 {
3568 int sysrq_toggle_seq_len = strlen(sysrq_toggle_seq);
3569
3570 sysrq_toggle_support(1);
3571 pr_info("SysRq is enabled by magic sequence '%*pE' on serial\n",
3572 sysrq_toggle_seq_len, sysrq_toggle_seq);
3573 }
3574 static DECLARE_WORK(sysrq_enable_work, uart_sysrq_on);
3575
3576 /**
3577 * uart_try_toggle_sysrq - Enables SysRq from serial line
3578 * @port: uart_port structure where char(s) after BREAK met
3579 * @ch: new character in the sequence after received BREAK
3580 *
3581 * Enables magic SysRq when the required sequence is met on port
3582 * (see CONFIG_MAGIC_SYSRQ_SERIAL_SEQUENCE).
3583 *
3584 * Returns: %false if @ch is out of enabling sequence and should be
3585 * handled some other way, %true if @ch was consumed.
3586 */
uart_try_toggle_sysrq(struct uart_port * port,u8 ch)3587 bool uart_try_toggle_sysrq(struct uart_port *port, u8 ch)
3588 {
3589 int sysrq_toggle_seq_len = strlen(sysrq_toggle_seq);
3590
3591 if (!sysrq_toggle_seq_len)
3592 return false;
3593
3594 BUILD_BUG_ON(ARRAY_SIZE(sysrq_toggle_seq) >= U8_MAX);
3595 if (sysrq_toggle_seq[port->sysrq_seq] != ch) {
3596 port->sysrq_seq = 0;
3597 return false;
3598 }
3599
3600 if (++port->sysrq_seq < sysrq_toggle_seq_len) {
3601 port->sysrq = jiffies + SYSRQ_TIMEOUT;
3602 return true;
3603 }
3604
3605 schedule_work(&sysrq_enable_work);
3606
3607 port->sysrq = 0;
3608 return true;
3609 }
3610 EXPORT_SYMBOL_GPL(uart_try_toggle_sysrq);
3611 #endif
3612
3613 /**
3614 * uart_get_rs485_mode() - retrieve rs485 properties for given uart
3615 * @port: uart device's target port
3616 *
3617 * This function implements the device tree binding described in
3618 * Documentation/devicetree/bindings/serial/rs485.txt.
3619 */
uart_get_rs485_mode(struct uart_port * port)3620 int uart_get_rs485_mode(struct uart_port *port)
3621 {
3622 struct serial_rs485 *rs485conf = &port->rs485;
3623 struct device *dev = port->dev;
3624 enum gpiod_flags dflags;
3625 struct gpio_desc *desc;
3626 u32 rs485_delay[2];
3627 int ret;
3628
3629 if (!(port->rs485_supported.flags & SER_RS485_ENABLED))
3630 return 0;
3631
3632 ret = device_property_read_u32_array(dev, "rs485-rts-delay",
3633 rs485_delay, 2);
3634 if (!ret) {
3635 rs485conf->delay_rts_before_send = rs485_delay[0];
3636 rs485conf->delay_rts_after_send = rs485_delay[1];
3637 } else {
3638 rs485conf->delay_rts_before_send = 0;
3639 rs485conf->delay_rts_after_send = 0;
3640 }
3641
3642 uart_sanitize_serial_rs485_delays(port, rs485conf);
3643
3644 /*
3645 * Clear full-duplex and enabled flags, set RTS polarity to active high
3646 * to get to a defined state with the following properties:
3647 */
3648 rs485conf->flags &= ~(SER_RS485_RX_DURING_TX | SER_RS485_ENABLED |
3649 SER_RS485_TERMINATE_BUS |
3650 SER_RS485_RTS_AFTER_SEND);
3651 rs485conf->flags |= SER_RS485_RTS_ON_SEND;
3652
3653 if (device_property_read_bool(dev, "rs485-rx-during-tx"))
3654 rs485conf->flags |= SER_RS485_RX_DURING_TX;
3655
3656 if (device_property_read_bool(dev, "linux,rs485-enabled-at-boot-time"))
3657 rs485conf->flags |= SER_RS485_ENABLED;
3658
3659 if (device_property_read_bool(dev, "rs485-rts-active-low")) {
3660 rs485conf->flags &= ~SER_RS485_RTS_ON_SEND;
3661 rs485conf->flags |= SER_RS485_RTS_AFTER_SEND;
3662 }
3663
3664 /*
3665 * Disabling termination by default is the safe choice: Else if many
3666 * bus participants enable it, no communication is possible at all.
3667 * Works fine for short cables and users may enable for longer cables.
3668 */
3669 desc = devm_gpiod_get_optional(dev, "rs485-term", GPIOD_OUT_LOW);
3670 if (IS_ERR(desc))
3671 return dev_err_probe(dev, PTR_ERR(desc), "Cannot get rs485-term-gpios\n");
3672 port->rs485_term_gpio = desc;
3673 if (port->rs485_term_gpio)
3674 port->rs485_supported.flags |= SER_RS485_TERMINATE_BUS;
3675
3676 dflags = (rs485conf->flags & SER_RS485_RX_DURING_TX) ?
3677 GPIOD_OUT_HIGH : GPIOD_OUT_LOW;
3678 desc = devm_gpiod_get_optional(dev, "rs485-rx-during-tx", dflags);
3679 if (IS_ERR(desc))
3680 return dev_err_probe(dev, PTR_ERR(desc), "Cannot get rs485-rx-during-tx-gpios\n");
3681 port->rs485_rx_during_tx_gpio = desc;
3682 if (port->rs485_rx_during_tx_gpio)
3683 port->rs485_supported.flags |= SER_RS485_RX_DURING_TX;
3684
3685 return 0;
3686 }
3687 EXPORT_SYMBOL_GPL(uart_get_rs485_mode);
3688
3689 /* Compile-time assertions for serial_rs485 layout */
3690 static_assert(offsetof(struct serial_rs485, padding) ==
3691 (offsetof(struct serial_rs485, delay_rts_after_send) + sizeof(__u32)));
3692 static_assert(offsetof(struct serial_rs485, padding1) ==
3693 offsetof(struct serial_rs485, padding[1]));
3694 static_assert((offsetof(struct serial_rs485, padding[4]) + sizeof(__u32)) ==
3695 sizeof(struct serial_rs485));
3696
3697 MODULE_DESCRIPTION("Serial driver core");
3698 MODULE_LICENSE("GPL");
3699