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