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