1 // SPDX-License-Identifier: GPL-2.0+
2 /*
3  *  Driver core for serial ports
4  *
5  *  Based on drivers/char/serial.c, by Linus Torvalds, Theodore Ts'o.
6  *
7  *  Copyright 1999 ARM Limited
8  *  Copyright (C) 2000-2001 Deep Blue Solutions Ltd.
9  */
10 #include <linux/module.h>
11 #include <linux/tty.h>
12 #include <linux/tty_flip.h>
13 #include <linux/slab.h>
14 #include <linux/sched/signal.h>
15 #include <linux/init.h>
16 #include <linux/console.h>
17 #include <linux/gpio/consumer.h>
18 #include <linux/of.h>
19 #include <linux/proc_fs.h>
20 #include <linux/seq_file.h>
21 #include <linux/device.h>
22 #include <linux/serial.h> /* for serial_state and serial_icounter_struct */
23 #include <linux/serial_core.h>
24 #include <linux/sysrq.h>
25 #include <linux/delay.h>
26 #include <linux/mutex.h>
27 #include <linux/math64.h>
28 #include <linux/security.h>
29 
30 #include <linux/irq.h>
31 #include <linux/uaccess.h>
32 
33 /*
34  * This is used to lock changes in serial line configuration.
35  */
36 static DEFINE_MUTEX(port_mutex);
37 
38 /*
39  * lockdep: port->lock is initialized in two places, but we
40  *          want only one lock-class:
41  */
42 static struct lock_class_key port_lock_key;
43 
44 #define HIGH_BITS_OFFSET	((sizeof(long)-sizeof(int))*8)
45 
46 /*
47  * Max time with active RTS before/after data is sent.
48  */
49 #define RS485_MAX_RTS_DELAY	100 /* msecs */
50 
51 static void uart_change_speed(struct tty_struct *tty, struct uart_state *state,
52 			      const struct ktermios *old_termios);
53 static void uart_wait_until_sent(struct tty_struct *tty, int timeout);
54 static void uart_change_pm(struct uart_state *state,
55 			   enum uart_pm_state pm_state);
56 
57 static void uart_port_shutdown(struct tty_port *port);
58 
uart_dcd_enabled(struct uart_port * uport)59 static int uart_dcd_enabled(struct uart_port *uport)
60 {
61 	return !!(uport->status & UPSTAT_DCD_ENABLE);
62 }
63 
uart_port_ref(struct uart_state * state)64 static inline struct uart_port *uart_port_ref(struct uart_state *state)
65 {
66 	if (atomic_add_unless(&state->refcount, 1, 0))
67 		return state->uart_port;
68 	return NULL;
69 }
70 
uart_port_deref(struct uart_port * uport)71 static inline void uart_port_deref(struct uart_port *uport)
72 {
73 	if (atomic_dec_and_test(&uport->state->refcount))
74 		wake_up(&uport->state->remove_wait);
75 }
76 
77 #define uart_port_lock(state, flags)					\
78 	({								\
79 		struct uart_port *__uport = uart_port_ref(state);	\
80 		if (__uport)						\
81 			spin_lock_irqsave(&__uport->lock, flags);	\
82 		__uport;						\
83 	})
84 
85 #define uart_port_unlock(uport, flags)					\
86 	({								\
87 		struct uart_port *__uport = uport;			\
88 		if (__uport) {						\
89 			spin_unlock_irqrestore(&__uport->lock, flags);	\
90 			uart_port_deref(__uport);			\
91 		}							\
92 	})
93 
uart_port_check(struct uart_state * state)94 static inline struct uart_port *uart_port_check(struct uart_state *state)
95 {
96 	lockdep_assert_held(&state->port.mutex);
97 	return state->uart_port;
98 }
99 
100 /**
101  * uart_write_wakeup - schedule write processing
102  * @port: port to be processed
103  *
104  * This routine is used by the interrupt handler to schedule processing in the
105  * software interrupt portion of the driver. A driver is expected to call this
106  * function when the number of characters in the transmit buffer have dropped
107  * below a threshold.
108  *
109  * Locking: @port->lock should be held
110  */
uart_write_wakeup(struct uart_port * port)111 void uart_write_wakeup(struct uart_port *port)
112 {
113 	struct uart_state *state = port->state;
114 	/*
115 	 * This means you called this function _after_ the port was
116 	 * closed.  No cookie for you.
117 	 */
118 	BUG_ON(!state);
119 	tty_port_tty_wakeup(&state->port);
120 }
121 EXPORT_SYMBOL(uart_write_wakeup);
122 
uart_stop(struct tty_struct * tty)123 static void uart_stop(struct tty_struct *tty)
124 {
125 	struct uart_state *state = tty->driver_data;
126 	struct uart_port *port;
127 	unsigned long flags;
128 
129 	port = uart_port_lock(state, flags);
130 	if (port)
131 		port->ops->stop_tx(port);
132 	uart_port_unlock(port, flags);
133 }
134 
__uart_start(struct tty_struct * tty)135 static void __uart_start(struct tty_struct *tty)
136 {
137 	struct uart_state *state = tty->driver_data;
138 	struct uart_port *port = state->uart_port;
139 
140 	if (port && !uart_tx_stopped(port))
141 		port->ops->start_tx(port);
142 }
143 
uart_start(struct tty_struct * tty)144 static void uart_start(struct tty_struct *tty)
145 {
146 	struct uart_state *state = tty->driver_data;
147 	struct uart_port *port;
148 	unsigned long flags;
149 
150 	port = uart_port_lock(state, flags);
151 	__uart_start(tty);
152 	uart_port_unlock(port, flags);
153 }
154 
155 static void
uart_update_mctrl(struct uart_port * port,unsigned int set,unsigned int clear)156 uart_update_mctrl(struct uart_port *port, unsigned int set, unsigned int clear)
157 {
158 	unsigned long flags;
159 	unsigned int old;
160 
161 	spin_lock_irqsave(&port->lock, flags);
162 	old = port->mctrl;
163 	port->mctrl = (old & ~clear) | set;
164 	if (old != port->mctrl && !(port->rs485.flags & SER_RS485_ENABLED))
165 		port->ops->set_mctrl(port, port->mctrl);
166 	spin_unlock_irqrestore(&port->lock, flags);
167 }
168 
169 #define uart_set_mctrl(port, set)	uart_update_mctrl(port, set, 0)
170 #define uart_clear_mctrl(port, clear)	uart_update_mctrl(port, 0, clear)
171 
uart_port_dtr_rts(struct uart_port * uport,int raise)172 static void uart_port_dtr_rts(struct uart_port *uport, int raise)
173 {
174 	if (raise)
175 		uart_set_mctrl(uport, TIOCM_DTR | TIOCM_RTS);
176 	else
177 		uart_clear_mctrl(uport, TIOCM_DTR | TIOCM_RTS);
178 }
179 
180 /*
181  * Startup the port.  This will be called once per open.  All calls
182  * will be serialised by the per-port mutex.
183  */
uart_port_startup(struct tty_struct * tty,struct uart_state * state,int init_hw)184 static int uart_port_startup(struct tty_struct *tty, struct uart_state *state,
185 		int init_hw)
186 {
187 	struct uart_port *uport = uart_port_check(state);
188 	unsigned long flags;
189 	unsigned long page;
190 	int retval = 0;
191 
192 	if (uport->type == PORT_UNKNOWN)
193 		return 1;
194 
195 	/*
196 	 * Make sure the device is in D0 state.
197 	 */
198 	uart_change_pm(state, UART_PM_STATE_ON);
199 
200 	/*
201 	 * Initialise and allocate the transmit and temporary
202 	 * buffer.
203 	 */
204 	page = get_zeroed_page(GFP_KERNEL);
205 	if (!page)
206 		return -ENOMEM;
207 
208 	uart_port_lock(state, flags);
209 	if (!state->xmit.buf) {
210 		state->xmit.buf = (unsigned char *) page;
211 		uart_circ_clear(&state->xmit);
212 		uart_port_unlock(uport, flags);
213 	} else {
214 		uart_port_unlock(uport, flags);
215 		/*
216 		 * Do not free() the page under the port lock, see
217 		 * uart_shutdown().
218 		 */
219 		free_page(page);
220 	}
221 
222 	retval = uport->ops->startup(uport);
223 	if (retval == 0) {
224 		if (uart_console(uport) && uport->cons->cflag) {
225 			tty->termios.c_cflag = uport->cons->cflag;
226 			tty->termios.c_ispeed = uport->cons->ispeed;
227 			tty->termios.c_ospeed = uport->cons->ospeed;
228 			uport->cons->cflag = 0;
229 			uport->cons->ispeed = 0;
230 			uport->cons->ospeed = 0;
231 		}
232 		/*
233 		 * Initialise the hardware port settings.
234 		 */
235 		uart_change_speed(tty, state, NULL);
236 
237 		/*
238 		 * Setup the RTS and DTR signals once the
239 		 * port is open and ready to respond.
240 		 */
241 		if (init_hw && C_BAUD(tty))
242 			uart_port_dtr_rts(uport, 1);
243 	}
244 
245 	/*
246 	 * This is to allow setserial on this port. People may want to set
247 	 * port/irq/type and then reconfigure the port properly if it failed
248 	 * now.
249 	 */
250 	if (retval && capable(CAP_SYS_ADMIN))
251 		return 1;
252 
253 	return retval;
254 }
255 
uart_startup(struct tty_struct * tty,struct uart_state * state,int init_hw)256 static int uart_startup(struct tty_struct *tty, struct uart_state *state,
257 		int init_hw)
258 {
259 	struct tty_port *port = &state->port;
260 	int retval;
261 
262 	if (tty_port_initialized(port))
263 		return 0;
264 
265 	retval = uart_port_startup(tty, state, init_hw);
266 	if (retval)
267 		set_bit(TTY_IO_ERROR, &tty->flags);
268 
269 	return retval;
270 }
271 
272 /*
273  * This routine will shutdown a serial port; interrupts are disabled, and
274  * DTR is dropped if the hangup on close termio flag is on.  Calls to
275  * uart_shutdown are serialised by the per-port semaphore.
276  *
277  * uport == NULL if uart_port has already been removed
278  */
uart_shutdown(struct tty_struct * tty,struct uart_state * state)279 static void uart_shutdown(struct tty_struct *tty, struct uart_state *state)
280 {
281 	struct uart_port *uport = uart_port_check(state);
282 	struct tty_port *port = &state->port;
283 	unsigned long flags;
284 	char *xmit_buf = NULL;
285 
286 	/*
287 	 * Set the TTY IO error marker
288 	 */
289 	if (tty)
290 		set_bit(TTY_IO_ERROR, &tty->flags);
291 
292 	if (tty_port_initialized(port)) {
293 		tty_port_set_initialized(port, 0);
294 
295 		/*
296 		 * Turn off DTR and RTS early.
297 		 */
298 		if (uport && uart_console(uport) && tty) {
299 			uport->cons->cflag = tty->termios.c_cflag;
300 			uport->cons->ispeed = tty->termios.c_ispeed;
301 			uport->cons->ospeed = tty->termios.c_ospeed;
302 		}
303 
304 		if (!tty || C_HUPCL(tty))
305 			uart_port_dtr_rts(uport, 0);
306 
307 		uart_port_shutdown(port);
308 	}
309 
310 	/*
311 	 * It's possible for shutdown to be called after suspend if we get
312 	 * a DCD drop (hangup) at just the right time.  Clear suspended bit so
313 	 * we don't try to resume a port that has been shutdown.
314 	 */
315 	tty_port_set_suspended(port, 0);
316 
317 	/*
318 	 * Do not free() the transmit buffer page under the port lock since
319 	 * this can create various circular locking scenarios. For instance,
320 	 * console driver may need to allocate/free a debug object, which
321 	 * can endup in printk() recursion.
322 	 */
323 	uart_port_lock(state, flags);
324 	xmit_buf = state->xmit.buf;
325 	state->xmit.buf = NULL;
326 	uart_port_unlock(uport, flags);
327 
328 	free_page((unsigned long)xmit_buf);
329 }
330 
331 /**
332  * uart_update_timeout - update per-port frame timing information
333  * @port: uart_port structure describing the port
334  * @cflag: termios cflag value
335  * @baud: speed of the port
336  *
337  * Set the @port frame timing information from which the FIFO timeout value is
338  * derived. The @cflag value should reflect the actual hardware settings as
339  * number of bits, parity, stop bits and baud rate is taken into account here.
340  *
341  * Locking: caller is expected to take @port->lock
342  */
343 void
uart_update_timeout(struct uart_port * port,unsigned int cflag,unsigned int baud)344 uart_update_timeout(struct uart_port *port, unsigned int cflag,
345 		    unsigned int baud)
346 {
347 	unsigned int size = tty_get_frame_size(cflag);
348 	u64 frame_time;
349 
350 	frame_time = (u64)size * NSEC_PER_SEC;
351 	port->frame_time = DIV64_U64_ROUND_UP(frame_time, baud);
352 }
353 EXPORT_SYMBOL(uart_update_timeout);
354 
355 /**
356  * uart_get_baud_rate - return baud rate for a particular port
357  * @port: uart_port structure describing the port in question.
358  * @termios: desired termios settings
359  * @old: old termios (or %NULL)
360  * @min: minimum acceptable baud rate
361  * @max: maximum acceptable baud rate
362  *
363  * Decode the termios structure into a numeric baud rate, taking account of the
364  * magic 38400 baud rate (with spd_* flags), and mapping the %B0 rate to 9600
365  * baud.
366  *
367  * If the new baud rate is invalid, try the @old termios setting. If it's still
368  * invalid, we try 9600 baud.
369  *
370  * The @termios structure is updated to reflect the baud rate we're actually
371  * going to be using. Don't do this for the case where B0 is requested ("hang
372  * up").
373  *
374  * Locking: caller dependent
375  */
376 unsigned int
uart_get_baud_rate(struct uart_port * port,struct ktermios * termios,const struct ktermios * old,unsigned int min,unsigned int max)377 uart_get_baud_rate(struct uart_port *port, struct ktermios *termios,
378 		   const struct ktermios *old, unsigned int min, unsigned int max)
379 {
380 	unsigned int try;
381 	unsigned int baud;
382 	unsigned int altbaud;
383 	int hung_up = 0;
384 	upf_t flags = port->flags & UPF_SPD_MASK;
385 
386 	switch (flags) {
387 	case UPF_SPD_HI:
388 		altbaud = 57600;
389 		break;
390 	case UPF_SPD_VHI:
391 		altbaud = 115200;
392 		break;
393 	case UPF_SPD_SHI:
394 		altbaud = 230400;
395 		break;
396 	case UPF_SPD_WARP:
397 		altbaud = 460800;
398 		break;
399 	default:
400 		altbaud = 38400;
401 		break;
402 	}
403 
404 	for (try = 0; try < 2; try++) {
405 		baud = tty_termios_baud_rate(termios);
406 
407 		/*
408 		 * The spd_hi, spd_vhi, spd_shi, spd_warp kludge...
409 		 * Die! Die! Die!
410 		 */
411 		if (try == 0 && baud == 38400)
412 			baud = altbaud;
413 
414 		/*
415 		 * Special case: B0 rate.
416 		 */
417 		if (baud == 0) {
418 			hung_up = 1;
419 			baud = 9600;
420 		}
421 
422 		if (baud >= min && baud <= max)
423 			return baud;
424 
425 		/*
426 		 * Oops, the quotient was zero.  Try again with
427 		 * the old baud rate if possible.
428 		 */
429 		termios->c_cflag &= ~CBAUD;
430 		if (old) {
431 			baud = tty_termios_baud_rate(old);
432 			if (!hung_up)
433 				tty_termios_encode_baud_rate(termios,
434 								baud, baud);
435 			old = NULL;
436 			continue;
437 		}
438 
439 		/*
440 		 * As a last resort, if the range cannot be met then clip to
441 		 * the nearest chip supported rate.
442 		 */
443 		if (!hung_up) {
444 			if (baud <= min)
445 				tty_termios_encode_baud_rate(termios,
446 							min + 1, min + 1);
447 			else
448 				tty_termios_encode_baud_rate(termios,
449 							max - 1, max - 1);
450 		}
451 	}
452 	/* Should never happen */
453 	WARN_ON(1);
454 	return 0;
455 }
456 EXPORT_SYMBOL(uart_get_baud_rate);
457 
458 /**
459  * uart_get_divisor - return uart clock divisor
460  * @port: uart_port structure describing the port
461  * @baud: desired baud rate
462  *
463  * Calculate the divisor (baud_base / baud) for the specified @baud,
464  * appropriately rounded.
465  *
466  * If 38400 baud and custom divisor is selected, return the custom divisor
467  * instead.
468  *
469  * Locking: caller dependent
470  */
471 unsigned int
uart_get_divisor(struct uart_port * port,unsigned int baud)472 uart_get_divisor(struct uart_port *port, unsigned int baud)
473 {
474 	unsigned int quot;
475 
476 	/*
477 	 * Old custom speed handling.
478 	 */
479 	if (baud == 38400 && (port->flags & UPF_SPD_MASK) == UPF_SPD_CUST)
480 		quot = port->custom_divisor;
481 	else
482 		quot = DIV_ROUND_CLOSEST(port->uartclk, 16 * baud);
483 
484 	return quot;
485 }
486 EXPORT_SYMBOL(uart_get_divisor);
487 
488 /* Caller holds port mutex */
uart_change_speed(struct tty_struct * tty,struct uart_state * state,const struct ktermios * old_termios)489 static void uart_change_speed(struct tty_struct *tty, struct uart_state *state,
490 			      const struct ktermios *old_termios)
491 {
492 	struct uart_port *uport = uart_port_check(state);
493 	struct ktermios *termios;
494 	int hw_stopped;
495 
496 	/*
497 	 * If we have no tty, termios, or the port does not exist,
498 	 * then we can't set the parameters for this port.
499 	 */
500 	if (!tty || uport->type == PORT_UNKNOWN)
501 		return;
502 
503 	termios = &tty->termios;
504 	uport->ops->set_termios(uport, termios, old_termios);
505 
506 	/*
507 	 * Set modem status enables based on termios cflag
508 	 */
509 	spin_lock_irq(&uport->lock);
510 	if (termios->c_cflag & CRTSCTS)
511 		uport->status |= UPSTAT_CTS_ENABLE;
512 	else
513 		uport->status &= ~UPSTAT_CTS_ENABLE;
514 
515 	if (termios->c_cflag & CLOCAL)
516 		uport->status &= ~UPSTAT_DCD_ENABLE;
517 	else
518 		uport->status |= UPSTAT_DCD_ENABLE;
519 
520 	/* reset sw-assisted CTS flow control based on (possibly) new mode */
521 	hw_stopped = uport->hw_stopped;
522 	uport->hw_stopped = uart_softcts_mode(uport) &&
523 				!(uport->ops->get_mctrl(uport) & TIOCM_CTS);
524 	if (uport->hw_stopped) {
525 		if (!hw_stopped)
526 			uport->ops->stop_tx(uport);
527 	} else {
528 		if (hw_stopped)
529 			__uart_start(tty);
530 	}
531 	spin_unlock_irq(&uport->lock);
532 }
533 
uart_put_char(struct tty_struct * tty,unsigned char c)534 static int uart_put_char(struct tty_struct *tty, unsigned char c)
535 {
536 	struct uart_state *state = tty->driver_data;
537 	struct uart_port *port;
538 	struct circ_buf *circ;
539 	unsigned long flags;
540 	int ret = 0;
541 
542 	circ = &state->xmit;
543 	port = uart_port_lock(state, flags);
544 	if (!circ->buf) {
545 		uart_port_unlock(port, flags);
546 		return 0;
547 	}
548 
549 	if (port && uart_circ_chars_free(circ) != 0) {
550 		circ->buf[circ->head] = c;
551 		circ->head = (circ->head + 1) & (UART_XMIT_SIZE - 1);
552 		ret = 1;
553 	}
554 	uart_port_unlock(port, flags);
555 	return ret;
556 }
557 
uart_flush_chars(struct tty_struct * tty)558 static void uart_flush_chars(struct tty_struct *tty)
559 {
560 	uart_start(tty);
561 }
562 
uart_write(struct tty_struct * tty,const unsigned char * buf,int count)563 static int uart_write(struct tty_struct *tty,
564 					const unsigned char *buf, int count)
565 {
566 	struct uart_state *state = tty->driver_data;
567 	struct uart_port *port;
568 	struct circ_buf *circ;
569 	unsigned long flags;
570 	int c, ret = 0;
571 
572 	/*
573 	 * This means you called this function _after_ the port was
574 	 * closed.  No cookie for you.
575 	 */
576 	if (!state) {
577 		WARN_ON(1);
578 		return -EL3HLT;
579 	}
580 
581 	port = uart_port_lock(state, flags);
582 	circ = &state->xmit;
583 	if (!circ->buf) {
584 		uart_port_unlock(port, flags);
585 		return 0;
586 	}
587 
588 	while (port) {
589 		c = CIRC_SPACE_TO_END(circ->head, circ->tail, UART_XMIT_SIZE);
590 		if (count < c)
591 			c = count;
592 		if (c <= 0)
593 			break;
594 		memcpy(circ->buf + circ->head, buf, c);
595 		circ->head = (circ->head + c) & (UART_XMIT_SIZE - 1);
596 		buf += c;
597 		count -= c;
598 		ret += c;
599 	}
600 
601 	__uart_start(tty);
602 	uart_port_unlock(port, flags);
603 	return ret;
604 }
605 
uart_write_room(struct tty_struct * tty)606 static unsigned int uart_write_room(struct tty_struct *tty)
607 {
608 	struct uart_state *state = tty->driver_data;
609 	struct uart_port *port;
610 	unsigned long flags;
611 	unsigned int ret;
612 
613 	port = uart_port_lock(state, flags);
614 	ret = uart_circ_chars_free(&state->xmit);
615 	uart_port_unlock(port, flags);
616 	return ret;
617 }
618 
uart_chars_in_buffer(struct tty_struct * tty)619 static unsigned int uart_chars_in_buffer(struct tty_struct *tty)
620 {
621 	struct uart_state *state = tty->driver_data;
622 	struct uart_port *port;
623 	unsigned long flags;
624 	unsigned int ret;
625 
626 	port = uart_port_lock(state, flags);
627 	ret = uart_circ_chars_pending(&state->xmit);
628 	uart_port_unlock(port, flags);
629 	return ret;
630 }
631 
uart_flush_buffer(struct tty_struct * tty)632 static void uart_flush_buffer(struct tty_struct *tty)
633 {
634 	struct uart_state *state = tty->driver_data;
635 	struct uart_port *port;
636 	unsigned long flags;
637 
638 	/*
639 	 * This means you called this function _after_ the port was
640 	 * closed.  No cookie for you.
641 	 */
642 	if (!state) {
643 		WARN_ON(1);
644 		return;
645 	}
646 
647 	pr_debug("uart_flush_buffer(%d) called\n", tty->index);
648 
649 	port = uart_port_lock(state, flags);
650 	if (!port)
651 		return;
652 	uart_circ_clear(&state->xmit);
653 	if (port->ops->flush_buffer)
654 		port->ops->flush_buffer(port);
655 	uart_port_unlock(port, flags);
656 	tty_port_tty_wakeup(&state->port);
657 }
658 
659 /*
660  * This function performs low-level write of high-priority XON/XOFF
661  * character and accounting for it.
662  *
663  * Requires uart_port to implement .serial_out().
664  */
uart_xchar_out(struct uart_port * uport,int offset)665 void uart_xchar_out(struct uart_port *uport, int offset)
666 {
667 	serial_port_out(uport, offset, uport->x_char);
668 	uport->icount.tx++;
669 	uport->x_char = 0;
670 }
671 EXPORT_SYMBOL_GPL(uart_xchar_out);
672 
673 /*
674  * This function is used to send a high-priority XON/XOFF character to
675  * the device
676  */
uart_send_xchar(struct tty_struct * tty,char ch)677 static void uart_send_xchar(struct tty_struct *tty, char ch)
678 {
679 	struct uart_state *state = tty->driver_data;
680 	struct uart_port *port;
681 	unsigned long flags;
682 
683 	port = uart_port_ref(state);
684 	if (!port)
685 		return;
686 
687 	if (port->ops->send_xchar)
688 		port->ops->send_xchar(port, ch);
689 	else {
690 		spin_lock_irqsave(&port->lock, flags);
691 		port->x_char = ch;
692 		if (ch)
693 			port->ops->start_tx(port);
694 		spin_unlock_irqrestore(&port->lock, flags);
695 	}
696 	uart_port_deref(port);
697 }
698 
uart_throttle(struct tty_struct * tty)699 static void uart_throttle(struct tty_struct *tty)
700 {
701 	struct uart_state *state = tty->driver_data;
702 	upstat_t mask = UPSTAT_SYNC_FIFO;
703 	struct uart_port *port;
704 
705 	port = uart_port_ref(state);
706 	if (!port)
707 		return;
708 
709 	if (I_IXOFF(tty))
710 		mask |= UPSTAT_AUTOXOFF;
711 	if (C_CRTSCTS(tty))
712 		mask |= UPSTAT_AUTORTS;
713 
714 	if (port->status & mask) {
715 		port->ops->throttle(port);
716 		mask &= ~port->status;
717 	}
718 
719 	if (mask & UPSTAT_AUTORTS)
720 		uart_clear_mctrl(port, TIOCM_RTS);
721 
722 	if (mask & UPSTAT_AUTOXOFF)
723 		uart_send_xchar(tty, STOP_CHAR(tty));
724 
725 	uart_port_deref(port);
726 }
727 
uart_unthrottle(struct tty_struct * tty)728 static void uart_unthrottle(struct tty_struct *tty)
729 {
730 	struct uart_state *state = tty->driver_data;
731 	upstat_t mask = UPSTAT_SYNC_FIFO;
732 	struct uart_port *port;
733 
734 	port = uart_port_ref(state);
735 	if (!port)
736 		return;
737 
738 	if (I_IXOFF(tty))
739 		mask |= UPSTAT_AUTOXOFF;
740 	if (C_CRTSCTS(tty))
741 		mask |= UPSTAT_AUTORTS;
742 
743 	if (port->status & mask) {
744 		port->ops->unthrottle(port);
745 		mask &= ~port->status;
746 	}
747 
748 	if (mask & UPSTAT_AUTORTS)
749 		uart_set_mctrl(port, TIOCM_RTS);
750 
751 	if (mask & UPSTAT_AUTOXOFF)
752 		uart_send_xchar(tty, START_CHAR(tty));
753 
754 	uart_port_deref(port);
755 }
756 
uart_get_info(struct tty_port * port,struct serial_struct * retinfo)757 static int uart_get_info(struct tty_port *port, struct serial_struct *retinfo)
758 {
759 	struct uart_state *state = container_of(port, struct uart_state, port);
760 	struct uart_port *uport;
761 	int ret = -ENODEV;
762 
763 	/*
764 	 * Ensure the state we copy is consistent and no hardware changes
765 	 * occur as we go
766 	 */
767 	mutex_lock(&port->mutex);
768 	uport = uart_port_check(state);
769 	if (!uport)
770 		goto out;
771 
772 	retinfo->type	    = uport->type;
773 	retinfo->line	    = uport->line;
774 	retinfo->port	    = uport->iobase;
775 	if (HIGH_BITS_OFFSET)
776 		retinfo->port_high = (long) uport->iobase >> HIGH_BITS_OFFSET;
777 	retinfo->irq		    = uport->irq;
778 	retinfo->flags	    = (__force int)uport->flags;
779 	retinfo->xmit_fifo_size  = uport->fifosize;
780 	retinfo->baud_base	    = uport->uartclk / 16;
781 	retinfo->close_delay	    = jiffies_to_msecs(port->close_delay) / 10;
782 	retinfo->closing_wait    = port->closing_wait == ASYNC_CLOSING_WAIT_NONE ?
783 				ASYNC_CLOSING_WAIT_NONE :
784 				jiffies_to_msecs(port->closing_wait) / 10;
785 	retinfo->custom_divisor  = uport->custom_divisor;
786 	retinfo->hub6	    = uport->hub6;
787 	retinfo->io_type         = uport->iotype;
788 	retinfo->iomem_reg_shift = uport->regshift;
789 	retinfo->iomem_base      = (void *)(unsigned long)uport->mapbase;
790 
791 	ret = 0;
792 out:
793 	mutex_unlock(&port->mutex);
794 	return ret;
795 }
796 
uart_get_info_user(struct tty_struct * tty,struct serial_struct * ss)797 static int uart_get_info_user(struct tty_struct *tty,
798 			 struct serial_struct *ss)
799 {
800 	struct uart_state *state = tty->driver_data;
801 	struct tty_port *port = &state->port;
802 
803 	return uart_get_info(port, ss) < 0 ? -EIO : 0;
804 }
805 
uart_set_info(struct tty_struct * tty,struct tty_port * port,struct uart_state * state,struct serial_struct * new_info)806 static int uart_set_info(struct tty_struct *tty, struct tty_port *port,
807 			 struct uart_state *state,
808 			 struct serial_struct *new_info)
809 {
810 	struct uart_port *uport = uart_port_check(state);
811 	unsigned long new_port;
812 	unsigned int change_irq, change_port, closing_wait;
813 	unsigned int old_custom_divisor, close_delay;
814 	upf_t old_flags, new_flags;
815 	int retval = 0;
816 
817 	if (!uport)
818 		return -EIO;
819 
820 	new_port = new_info->port;
821 	if (HIGH_BITS_OFFSET)
822 		new_port += (unsigned long) new_info->port_high << HIGH_BITS_OFFSET;
823 
824 	new_info->irq = irq_canonicalize(new_info->irq);
825 	close_delay = msecs_to_jiffies(new_info->close_delay * 10);
826 	closing_wait = new_info->closing_wait == ASYNC_CLOSING_WAIT_NONE ?
827 			ASYNC_CLOSING_WAIT_NONE :
828 			msecs_to_jiffies(new_info->closing_wait * 10);
829 
830 
831 	change_irq  = !(uport->flags & UPF_FIXED_PORT)
832 		&& new_info->irq != uport->irq;
833 
834 	/*
835 	 * Since changing the 'type' of the port changes its resource
836 	 * allocations, we should treat type changes the same as
837 	 * IO port changes.
838 	 */
839 	change_port = !(uport->flags & UPF_FIXED_PORT)
840 		&& (new_port != uport->iobase ||
841 		    (unsigned long)new_info->iomem_base != uport->mapbase ||
842 		    new_info->hub6 != uport->hub6 ||
843 		    new_info->io_type != uport->iotype ||
844 		    new_info->iomem_reg_shift != uport->regshift ||
845 		    new_info->type != uport->type);
846 
847 	old_flags = uport->flags;
848 	new_flags = (__force upf_t)new_info->flags;
849 	old_custom_divisor = uport->custom_divisor;
850 
851 	if (!capable(CAP_SYS_ADMIN)) {
852 		retval = -EPERM;
853 		if (change_irq || change_port ||
854 		    (new_info->baud_base != uport->uartclk / 16) ||
855 		    (close_delay != port->close_delay) ||
856 		    (closing_wait != port->closing_wait) ||
857 		    (new_info->xmit_fifo_size &&
858 		     new_info->xmit_fifo_size != uport->fifosize) ||
859 		    (((new_flags ^ old_flags) & ~UPF_USR_MASK) != 0))
860 			goto exit;
861 		uport->flags = ((uport->flags & ~UPF_USR_MASK) |
862 			       (new_flags & UPF_USR_MASK));
863 		uport->custom_divisor = new_info->custom_divisor;
864 		goto check_and_exit;
865 	}
866 
867 	if (change_irq || change_port) {
868 		retval = security_locked_down(LOCKDOWN_TIOCSSERIAL);
869 		if (retval)
870 			goto exit;
871 	}
872 
873 	/*
874 	 * Ask the low level driver to verify the settings.
875 	 */
876 	if (uport->ops->verify_port)
877 		retval = uport->ops->verify_port(uport, new_info);
878 
879 	if ((new_info->irq >= nr_irqs) || (new_info->irq < 0) ||
880 	    (new_info->baud_base < 9600))
881 		retval = -EINVAL;
882 
883 	if (retval)
884 		goto exit;
885 
886 	if (change_port || change_irq) {
887 		retval = -EBUSY;
888 
889 		/*
890 		 * Make sure that we are the sole user of this port.
891 		 */
892 		if (tty_port_users(port) > 1)
893 			goto exit;
894 
895 		/*
896 		 * We need to shutdown the serial port at the old
897 		 * port/type/irq combination.
898 		 */
899 		uart_shutdown(tty, state);
900 	}
901 
902 	if (change_port) {
903 		unsigned long old_iobase, old_mapbase;
904 		unsigned int old_type, old_iotype, old_hub6, old_shift;
905 
906 		old_iobase = uport->iobase;
907 		old_mapbase = uport->mapbase;
908 		old_type = uport->type;
909 		old_hub6 = uport->hub6;
910 		old_iotype = uport->iotype;
911 		old_shift = uport->regshift;
912 
913 		/*
914 		 * Free and release old regions
915 		 */
916 		if (old_type != PORT_UNKNOWN && uport->ops->release_port)
917 			uport->ops->release_port(uport);
918 
919 		uport->iobase = new_port;
920 		uport->type = new_info->type;
921 		uport->hub6 = new_info->hub6;
922 		uport->iotype = new_info->io_type;
923 		uport->regshift = new_info->iomem_reg_shift;
924 		uport->mapbase = (unsigned long)new_info->iomem_base;
925 
926 		/*
927 		 * Claim and map the new regions
928 		 */
929 		if (uport->type != PORT_UNKNOWN && uport->ops->request_port) {
930 			retval = uport->ops->request_port(uport);
931 		} else {
932 			/* Always success - Jean II */
933 			retval = 0;
934 		}
935 
936 		/*
937 		 * If we fail to request resources for the
938 		 * new port, try to restore the old settings.
939 		 */
940 		if (retval) {
941 			uport->iobase = old_iobase;
942 			uport->type = old_type;
943 			uport->hub6 = old_hub6;
944 			uport->iotype = old_iotype;
945 			uport->regshift = old_shift;
946 			uport->mapbase = old_mapbase;
947 
948 			if (old_type != PORT_UNKNOWN) {
949 				retval = uport->ops->request_port(uport);
950 				/*
951 				 * If we failed to restore the old settings,
952 				 * we fail like this.
953 				 */
954 				if (retval)
955 					uport->type = PORT_UNKNOWN;
956 
957 				/*
958 				 * We failed anyway.
959 				 */
960 				retval = -EBUSY;
961 			}
962 
963 			/* Added to return the correct error -Ram Gupta */
964 			goto exit;
965 		}
966 	}
967 
968 	if (change_irq)
969 		uport->irq      = new_info->irq;
970 	if (!(uport->flags & UPF_FIXED_PORT))
971 		uport->uartclk  = new_info->baud_base * 16;
972 	uport->flags            = (uport->flags & ~UPF_CHANGE_MASK) |
973 				 (new_flags & UPF_CHANGE_MASK);
974 	uport->custom_divisor   = new_info->custom_divisor;
975 	port->close_delay     = close_delay;
976 	port->closing_wait    = closing_wait;
977 	if (new_info->xmit_fifo_size)
978 		uport->fifosize = new_info->xmit_fifo_size;
979 
980  check_and_exit:
981 	retval = 0;
982 	if (uport->type == PORT_UNKNOWN)
983 		goto exit;
984 	if (tty_port_initialized(port)) {
985 		if (((old_flags ^ uport->flags) & UPF_SPD_MASK) ||
986 		    old_custom_divisor != uport->custom_divisor) {
987 			/*
988 			 * If they're setting up a custom divisor or speed,
989 			 * instead of clearing it, then bitch about it.
990 			 */
991 			if (uport->flags & UPF_SPD_MASK) {
992 				dev_notice_ratelimited(uport->dev,
993 				       "%s sets custom speed on %s. This is deprecated.\n",
994 				      current->comm,
995 				      tty_name(port->tty));
996 			}
997 			uart_change_speed(tty, state, NULL);
998 		}
999 	} else {
1000 		retval = uart_startup(tty, state, 1);
1001 		if (retval == 0)
1002 			tty_port_set_initialized(port, true);
1003 		if (retval > 0)
1004 			retval = 0;
1005 	}
1006  exit:
1007 	return retval;
1008 }
1009 
uart_set_info_user(struct tty_struct * tty,struct serial_struct * ss)1010 static int uart_set_info_user(struct tty_struct *tty, struct serial_struct *ss)
1011 {
1012 	struct uart_state *state = tty->driver_data;
1013 	struct tty_port *port = &state->port;
1014 	int retval;
1015 
1016 	down_write(&tty->termios_rwsem);
1017 	/*
1018 	 * This semaphore protects port->count.  It is also
1019 	 * very useful to prevent opens.  Also, take the
1020 	 * port configuration semaphore to make sure that a
1021 	 * module insertion/removal doesn't change anything
1022 	 * under us.
1023 	 */
1024 	mutex_lock(&port->mutex);
1025 	retval = uart_set_info(tty, port, state, ss);
1026 	mutex_unlock(&port->mutex);
1027 	up_write(&tty->termios_rwsem);
1028 	return retval;
1029 }
1030 
1031 /**
1032  * uart_get_lsr_info - get line status register info
1033  * @tty: tty associated with the UART
1034  * @state: UART being queried
1035  * @value: returned modem value
1036  */
uart_get_lsr_info(struct tty_struct * tty,struct uart_state * state,unsigned int __user * value)1037 static int uart_get_lsr_info(struct tty_struct *tty,
1038 			struct uart_state *state, unsigned int __user *value)
1039 {
1040 	struct uart_port *uport = uart_port_check(state);
1041 	unsigned int result;
1042 
1043 	result = uport->ops->tx_empty(uport);
1044 
1045 	/*
1046 	 * If we're about to load something into the transmit
1047 	 * register, we'll pretend the transmitter isn't empty to
1048 	 * avoid a race condition (depending on when the transmit
1049 	 * interrupt happens).
1050 	 */
1051 	if (uport->x_char ||
1052 	    ((uart_circ_chars_pending(&state->xmit) > 0) &&
1053 	     !uart_tx_stopped(uport)))
1054 		result &= ~TIOCSER_TEMT;
1055 
1056 	return put_user(result, value);
1057 }
1058 
uart_tiocmget(struct tty_struct * tty)1059 static int uart_tiocmget(struct tty_struct *tty)
1060 {
1061 	struct uart_state *state = tty->driver_data;
1062 	struct tty_port *port = &state->port;
1063 	struct uart_port *uport;
1064 	int result = -EIO;
1065 
1066 	mutex_lock(&port->mutex);
1067 	uport = uart_port_check(state);
1068 	if (!uport)
1069 		goto out;
1070 
1071 	if (!tty_io_error(tty)) {
1072 		result = uport->mctrl;
1073 		spin_lock_irq(&uport->lock);
1074 		result |= uport->ops->get_mctrl(uport);
1075 		spin_unlock_irq(&uport->lock);
1076 	}
1077 out:
1078 	mutex_unlock(&port->mutex);
1079 	return result;
1080 }
1081 
1082 static int
uart_tiocmset(struct tty_struct * tty,unsigned int set,unsigned int clear)1083 uart_tiocmset(struct tty_struct *tty, unsigned int set, unsigned int clear)
1084 {
1085 	struct uart_state *state = tty->driver_data;
1086 	struct tty_port *port = &state->port;
1087 	struct uart_port *uport;
1088 	int ret = -EIO;
1089 
1090 	mutex_lock(&port->mutex);
1091 	uport = uart_port_check(state);
1092 	if (!uport)
1093 		goto out;
1094 
1095 	if (!tty_io_error(tty)) {
1096 		uart_update_mctrl(uport, set, clear);
1097 		ret = 0;
1098 	}
1099 out:
1100 	mutex_unlock(&port->mutex);
1101 	return ret;
1102 }
1103 
uart_break_ctl(struct tty_struct * tty,int break_state)1104 static int uart_break_ctl(struct tty_struct *tty, int break_state)
1105 {
1106 	struct uart_state *state = tty->driver_data;
1107 	struct tty_port *port = &state->port;
1108 	struct uart_port *uport;
1109 	int ret = -EIO;
1110 
1111 	mutex_lock(&port->mutex);
1112 	uport = uart_port_check(state);
1113 	if (!uport)
1114 		goto out;
1115 
1116 	if (uport->type != PORT_UNKNOWN && uport->ops->break_ctl)
1117 		uport->ops->break_ctl(uport, break_state);
1118 	ret = 0;
1119 out:
1120 	mutex_unlock(&port->mutex);
1121 	return ret;
1122 }
1123 
uart_do_autoconfig(struct tty_struct * tty,struct uart_state * state)1124 static int uart_do_autoconfig(struct tty_struct *tty, struct uart_state *state)
1125 {
1126 	struct tty_port *port = &state->port;
1127 	struct uart_port *uport;
1128 	int flags, ret;
1129 
1130 	if (!capable(CAP_SYS_ADMIN))
1131 		return -EPERM;
1132 
1133 	/*
1134 	 * Take the per-port semaphore.  This prevents count from
1135 	 * changing, and hence any extra opens of the port while
1136 	 * we're auto-configuring.
1137 	 */
1138 	if (mutex_lock_interruptible(&port->mutex))
1139 		return -ERESTARTSYS;
1140 
1141 	uport = uart_port_check(state);
1142 	if (!uport) {
1143 		ret = -EIO;
1144 		goto out;
1145 	}
1146 
1147 	ret = -EBUSY;
1148 	if (tty_port_users(port) == 1) {
1149 		uart_shutdown(tty, state);
1150 
1151 		/*
1152 		 * If we already have a port type configured,
1153 		 * we must release its resources.
1154 		 */
1155 		if (uport->type != PORT_UNKNOWN && uport->ops->release_port)
1156 			uport->ops->release_port(uport);
1157 
1158 		flags = UART_CONFIG_TYPE;
1159 		if (uport->flags & UPF_AUTO_IRQ)
1160 			flags |= UART_CONFIG_IRQ;
1161 
1162 		/*
1163 		 * This will claim the ports resources if
1164 		 * a port is found.
1165 		 */
1166 		uport->ops->config_port(uport, flags);
1167 
1168 		ret = uart_startup(tty, state, 1);
1169 		if (ret == 0)
1170 			tty_port_set_initialized(port, true);
1171 		if (ret > 0)
1172 			ret = 0;
1173 	}
1174 out:
1175 	mutex_unlock(&port->mutex);
1176 	return ret;
1177 }
1178 
uart_enable_ms(struct uart_port * uport)1179 static void uart_enable_ms(struct uart_port *uport)
1180 {
1181 	/*
1182 	 * Force modem status interrupts on
1183 	 */
1184 	if (uport->ops->enable_ms)
1185 		uport->ops->enable_ms(uport);
1186 }
1187 
1188 /*
1189  * Wait for any of the 4 modem inputs (DCD,RI,DSR,CTS) to change
1190  * - mask passed in arg for lines of interest
1191  *   (use |'ed TIOCM_RNG/DSR/CD/CTS for masking)
1192  * Caller should use TIOCGICOUNT to see which one it was
1193  *
1194  * FIXME: This wants extracting into a common all driver implementation
1195  * of TIOCMWAIT using tty_port.
1196  */
uart_wait_modem_status(struct uart_state * state,unsigned long arg)1197 static int uart_wait_modem_status(struct uart_state *state, unsigned long arg)
1198 {
1199 	struct uart_port *uport;
1200 	struct tty_port *port = &state->port;
1201 	DECLARE_WAITQUEUE(wait, current);
1202 	struct uart_icount cprev, cnow;
1203 	int ret;
1204 
1205 	/*
1206 	 * note the counters on entry
1207 	 */
1208 	uport = uart_port_ref(state);
1209 	if (!uport)
1210 		return -EIO;
1211 	spin_lock_irq(&uport->lock);
1212 	memcpy(&cprev, &uport->icount, sizeof(struct uart_icount));
1213 	uart_enable_ms(uport);
1214 	spin_unlock_irq(&uport->lock);
1215 
1216 	add_wait_queue(&port->delta_msr_wait, &wait);
1217 	for (;;) {
1218 		spin_lock_irq(&uport->lock);
1219 		memcpy(&cnow, &uport->icount, sizeof(struct uart_icount));
1220 		spin_unlock_irq(&uport->lock);
1221 
1222 		set_current_state(TASK_INTERRUPTIBLE);
1223 
1224 		if (((arg & TIOCM_RNG) && (cnow.rng != cprev.rng)) ||
1225 		    ((arg & TIOCM_DSR) && (cnow.dsr != cprev.dsr)) ||
1226 		    ((arg & TIOCM_CD)  && (cnow.dcd != cprev.dcd)) ||
1227 		    ((arg & TIOCM_CTS) && (cnow.cts != cprev.cts))) {
1228 			ret = 0;
1229 			break;
1230 		}
1231 
1232 		schedule();
1233 
1234 		/* see if a signal did it */
1235 		if (signal_pending(current)) {
1236 			ret = -ERESTARTSYS;
1237 			break;
1238 		}
1239 
1240 		cprev = cnow;
1241 	}
1242 	__set_current_state(TASK_RUNNING);
1243 	remove_wait_queue(&port->delta_msr_wait, &wait);
1244 	uart_port_deref(uport);
1245 
1246 	return ret;
1247 }
1248 
1249 /*
1250  * Get counter of input serial line interrupts (DCD,RI,DSR,CTS)
1251  * Return: write counters to the user passed counter struct
1252  * NB: both 1->0 and 0->1 transitions are counted except for
1253  *     RI where only 0->1 is counted.
1254  */
uart_get_icount(struct tty_struct * tty,struct serial_icounter_struct * icount)1255 static int uart_get_icount(struct tty_struct *tty,
1256 			  struct serial_icounter_struct *icount)
1257 {
1258 	struct uart_state *state = tty->driver_data;
1259 	struct uart_icount cnow;
1260 	struct uart_port *uport;
1261 
1262 	uport = uart_port_ref(state);
1263 	if (!uport)
1264 		return -EIO;
1265 	spin_lock_irq(&uport->lock);
1266 	memcpy(&cnow, &uport->icount, sizeof(struct uart_icount));
1267 	spin_unlock_irq(&uport->lock);
1268 	uart_port_deref(uport);
1269 
1270 	icount->cts         = cnow.cts;
1271 	icount->dsr         = cnow.dsr;
1272 	icount->rng         = cnow.rng;
1273 	icount->dcd         = cnow.dcd;
1274 	icount->rx          = cnow.rx;
1275 	icount->tx          = cnow.tx;
1276 	icount->frame       = cnow.frame;
1277 	icount->overrun     = cnow.overrun;
1278 	icount->parity      = cnow.parity;
1279 	icount->brk         = cnow.brk;
1280 	icount->buf_overrun = cnow.buf_overrun;
1281 
1282 	return 0;
1283 }
1284 
1285 #define SER_RS485_LEGACY_FLAGS	(SER_RS485_ENABLED | SER_RS485_RTS_ON_SEND | \
1286 				 SER_RS485_RTS_AFTER_SEND | SER_RS485_RX_DURING_TX | \
1287 				 SER_RS485_TERMINATE_BUS)
1288 
uart_check_rs485_flags(struct uart_port * port,struct serial_rs485 * rs485)1289 static int uart_check_rs485_flags(struct uart_port *port, struct serial_rs485 *rs485)
1290 {
1291 	u32 flags = rs485->flags;
1292 
1293 	/* Don't return -EINVAL for unsupported legacy flags */
1294 	flags &= ~SER_RS485_LEGACY_FLAGS;
1295 
1296 	/*
1297 	 * For any bit outside of the legacy ones that is not supported by
1298 	 * the driver, return -EINVAL.
1299 	 */
1300 	if (flags & ~port->rs485_supported.flags)
1301 		return -EINVAL;
1302 
1303 	/* Asking for address w/o addressing mode? */
1304 	if (!(rs485->flags & SER_RS485_ADDRB) &&
1305 	    (rs485->flags & (SER_RS485_ADDR_RECV|SER_RS485_ADDR_DEST)))
1306 		return -EINVAL;
1307 
1308 	/* Address given but not enabled? */
1309 	if (!(rs485->flags & SER_RS485_ADDR_RECV) && rs485->addr_recv)
1310 		return -EINVAL;
1311 	if (!(rs485->flags & SER_RS485_ADDR_DEST) && rs485->addr_dest)
1312 		return -EINVAL;
1313 
1314 	return 0;
1315 }
1316 
uart_sanitize_serial_rs485_delays(struct uart_port * port,struct serial_rs485 * rs485)1317 static void uart_sanitize_serial_rs485_delays(struct uart_port *port,
1318 					      struct serial_rs485 *rs485)
1319 {
1320 	if (!port->rs485_supported.delay_rts_before_send) {
1321 		if (rs485->delay_rts_before_send) {
1322 			dev_warn_ratelimited(port->dev,
1323 				"%s (%d): RTS delay before sending not supported\n",
1324 				port->name, port->line);
1325 		}
1326 		rs485->delay_rts_before_send = 0;
1327 	} else if (rs485->delay_rts_before_send > RS485_MAX_RTS_DELAY) {
1328 		rs485->delay_rts_before_send = RS485_MAX_RTS_DELAY;
1329 		dev_warn_ratelimited(port->dev,
1330 			"%s (%d): RTS delay before sending clamped to %u ms\n",
1331 			port->name, port->line, rs485->delay_rts_before_send);
1332 	}
1333 
1334 	if (!port->rs485_supported.delay_rts_after_send) {
1335 		if (rs485->delay_rts_after_send) {
1336 			dev_warn_ratelimited(port->dev,
1337 				"%s (%d): RTS delay after sending not supported\n",
1338 				port->name, port->line);
1339 		}
1340 		rs485->delay_rts_after_send = 0;
1341 	} else if (rs485->delay_rts_after_send > RS485_MAX_RTS_DELAY) {
1342 		rs485->delay_rts_after_send = RS485_MAX_RTS_DELAY;
1343 		dev_warn_ratelimited(port->dev,
1344 			"%s (%d): RTS delay after sending clamped to %u ms\n",
1345 			port->name, port->line, rs485->delay_rts_after_send);
1346 	}
1347 }
1348 
uart_sanitize_serial_rs485(struct uart_port * port,struct serial_rs485 * rs485)1349 static void uart_sanitize_serial_rs485(struct uart_port *port, struct serial_rs485 *rs485)
1350 {
1351 	u32 supported_flags = port->rs485_supported.flags;
1352 
1353 	if (!(rs485->flags & SER_RS485_ENABLED)) {
1354 		memset(rs485, 0, sizeof(*rs485));
1355 		return;
1356 	}
1357 
1358 	/* Pick sane settings if the user hasn't */
1359 	if ((supported_flags & (SER_RS485_RTS_ON_SEND|SER_RS485_RTS_AFTER_SEND)) &&
1360 	    !(rs485->flags & SER_RS485_RTS_ON_SEND) ==
1361 	    !(rs485->flags & SER_RS485_RTS_AFTER_SEND)) {
1362 		dev_warn_ratelimited(port->dev,
1363 			"%s (%d): invalid RTS setting, using RTS_ON_SEND instead\n",
1364 			port->name, port->line);
1365 		rs485->flags |= SER_RS485_RTS_ON_SEND;
1366 		rs485->flags &= ~SER_RS485_RTS_AFTER_SEND;
1367 		supported_flags |= SER_RS485_RTS_ON_SEND|SER_RS485_RTS_AFTER_SEND;
1368 	}
1369 
1370 	rs485->flags &= supported_flags;
1371 
1372 	uart_sanitize_serial_rs485_delays(port, rs485);
1373 
1374 	/* Return clean padding area to userspace */
1375 	memset(rs485->padding0, 0, sizeof(rs485->padding0));
1376 	memset(rs485->padding1, 0, sizeof(rs485->padding1));
1377 }
1378 
uart_set_rs485_termination(struct uart_port * port,const struct serial_rs485 * rs485)1379 static void uart_set_rs485_termination(struct uart_port *port,
1380 				       const struct serial_rs485 *rs485)
1381 {
1382 	if (!(rs485->flags & SER_RS485_ENABLED))
1383 		return;
1384 
1385 	gpiod_set_value_cansleep(port->rs485_term_gpio,
1386 				 !!(rs485->flags & SER_RS485_TERMINATE_BUS));
1387 }
1388 
uart_rs485_config(struct uart_port * port)1389 static int uart_rs485_config(struct uart_port *port)
1390 {
1391 	struct serial_rs485 *rs485 = &port->rs485;
1392 	int ret;
1393 
1394 	uart_sanitize_serial_rs485(port, rs485);
1395 	uart_set_rs485_termination(port, rs485);
1396 
1397 	ret = port->rs485_config(port, NULL, rs485);
1398 	if (ret)
1399 		memset(rs485, 0, sizeof(*rs485));
1400 
1401 	return ret;
1402 }
1403 
uart_get_rs485_config(struct uart_port * port,struct serial_rs485 __user * rs485)1404 static int uart_get_rs485_config(struct uart_port *port,
1405 			 struct serial_rs485 __user *rs485)
1406 {
1407 	unsigned long flags;
1408 	struct serial_rs485 aux;
1409 
1410 	spin_lock_irqsave(&port->lock, flags);
1411 	aux = port->rs485;
1412 	spin_unlock_irqrestore(&port->lock, flags);
1413 
1414 	if (copy_to_user(rs485, &aux, sizeof(aux)))
1415 		return -EFAULT;
1416 
1417 	return 0;
1418 }
1419 
uart_set_rs485_config(struct tty_struct * tty,struct uart_port * port,struct serial_rs485 __user * rs485_user)1420 static int uart_set_rs485_config(struct tty_struct *tty, struct uart_port *port,
1421 			 struct serial_rs485 __user *rs485_user)
1422 {
1423 	struct serial_rs485 rs485;
1424 	int ret;
1425 	unsigned long flags;
1426 
1427 	if (!port->rs485_config)
1428 		return -ENOTTY;
1429 
1430 	if (copy_from_user(&rs485, rs485_user, sizeof(*rs485_user)))
1431 		return -EFAULT;
1432 
1433 	ret = uart_check_rs485_flags(port, &rs485);
1434 	if (ret)
1435 		return ret;
1436 	uart_sanitize_serial_rs485(port, &rs485);
1437 	uart_set_rs485_termination(port, &rs485);
1438 
1439 	spin_lock_irqsave(&port->lock, flags);
1440 	ret = port->rs485_config(port, &tty->termios, &rs485);
1441 	if (!ret) {
1442 		port->rs485 = rs485;
1443 
1444 		/* Reset RTS and other mctrl lines when disabling RS485 */
1445 		if (!(rs485.flags & SER_RS485_ENABLED))
1446 			port->ops->set_mctrl(port, port->mctrl);
1447 	}
1448 	spin_unlock_irqrestore(&port->lock, flags);
1449 	if (ret)
1450 		return ret;
1451 
1452 	if (copy_to_user(rs485_user, &port->rs485, sizeof(port->rs485)))
1453 		return -EFAULT;
1454 
1455 	return 0;
1456 }
1457 
uart_get_iso7816_config(struct uart_port * port,struct serial_iso7816 __user * iso7816)1458 static int uart_get_iso7816_config(struct uart_port *port,
1459 				   struct serial_iso7816 __user *iso7816)
1460 {
1461 	unsigned long flags;
1462 	struct serial_iso7816 aux;
1463 
1464 	if (!port->iso7816_config)
1465 		return -ENOTTY;
1466 
1467 	spin_lock_irqsave(&port->lock, flags);
1468 	aux = port->iso7816;
1469 	spin_unlock_irqrestore(&port->lock, flags);
1470 
1471 	if (copy_to_user(iso7816, &aux, sizeof(aux)))
1472 		return -EFAULT;
1473 
1474 	return 0;
1475 }
1476 
uart_set_iso7816_config(struct uart_port * port,struct serial_iso7816 __user * iso7816_user)1477 static int uart_set_iso7816_config(struct uart_port *port,
1478 				   struct serial_iso7816 __user *iso7816_user)
1479 {
1480 	struct serial_iso7816 iso7816;
1481 	int i, ret;
1482 	unsigned long flags;
1483 
1484 	if (!port->iso7816_config)
1485 		return -ENOTTY;
1486 
1487 	if (copy_from_user(&iso7816, iso7816_user, sizeof(*iso7816_user)))
1488 		return -EFAULT;
1489 
1490 	/*
1491 	 * There are 5 words reserved for future use. Check that userspace
1492 	 * doesn't put stuff in there to prevent breakages in the future.
1493 	 */
1494 	for (i = 0; i < 5; i++)
1495 		if (iso7816.reserved[i])
1496 			return -EINVAL;
1497 
1498 	spin_lock_irqsave(&port->lock, flags);
1499 	ret = port->iso7816_config(port, &iso7816);
1500 	spin_unlock_irqrestore(&port->lock, flags);
1501 	if (ret)
1502 		return ret;
1503 
1504 	if (copy_to_user(iso7816_user, &port->iso7816, sizeof(port->iso7816)))
1505 		return -EFAULT;
1506 
1507 	return 0;
1508 }
1509 
1510 /*
1511  * Called via sys_ioctl.  We can use spin_lock_irq() here.
1512  */
1513 static int
uart_ioctl(struct tty_struct * tty,unsigned int cmd,unsigned long arg)1514 uart_ioctl(struct tty_struct *tty, unsigned int cmd, unsigned long arg)
1515 {
1516 	struct uart_state *state = tty->driver_data;
1517 	struct tty_port *port = &state->port;
1518 	struct uart_port *uport;
1519 	void __user *uarg = (void __user *)arg;
1520 	int ret = -ENOIOCTLCMD;
1521 
1522 
1523 	/*
1524 	 * These ioctls don't rely on the hardware to be present.
1525 	 */
1526 	switch (cmd) {
1527 	case TIOCSERCONFIG:
1528 		down_write(&tty->termios_rwsem);
1529 		ret = uart_do_autoconfig(tty, state);
1530 		up_write(&tty->termios_rwsem);
1531 		break;
1532 	}
1533 
1534 	if (ret != -ENOIOCTLCMD)
1535 		goto out;
1536 
1537 	if (tty_io_error(tty)) {
1538 		ret = -EIO;
1539 		goto out;
1540 	}
1541 
1542 	/*
1543 	 * The following should only be used when hardware is present.
1544 	 */
1545 	switch (cmd) {
1546 	case TIOCMIWAIT:
1547 		ret = uart_wait_modem_status(state, arg);
1548 		break;
1549 	}
1550 
1551 	if (ret != -ENOIOCTLCMD)
1552 		goto out;
1553 
1554 	/* rs485_config requires more locking than others */
1555 	if (cmd == TIOCGRS485)
1556 		down_write(&tty->termios_rwsem);
1557 
1558 	mutex_lock(&port->mutex);
1559 	uport = uart_port_check(state);
1560 
1561 	if (!uport || tty_io_error(tty)) {
1562 		ret = -EIO;
1563 		goto out_up;
1564 	}
1565 
1566 	/*
1567 	 * All these rely on hardware being present and need to be
1568 	 * protected against the tty being hung up.
1569 	 */
1570 
1571 	switch (cmd) {
1572 	case TIOCSERGETLSR: /* Get line status register */
1573 		ret = uart_get_lsr_info(tty, state, uarg);
1574 		break;
1575 
1576 	case TIOCGRS485:
1577 		ret = uart_get_rs485_config(uport, uarg);
1578 		break;
1579 
1580 	case TIOCSRS485:
1581 		ret = uart_set_rs485_config(tty, uport, uarg);
1582 		break;
1583 
1584 	case TIOCSISO7816:
1585 		ret = uart_set_iso7816_config(state->uart_port, uarg);
1586 		break;
1587 
1588 	case TIOCGISO7816:
1589 		ret = uart_get_iso7816_config(state->uart_port, uarg);
1590 		break;
1591 	default:
1592 		if (uport->ops->ioctl)
1593 			ret = uport->ops->ioctl(uport, cmd, arg);
1594 		break;
1595 	}
1596 out_up:
1597 	mutex_unlock(&port->mutex);
1598 	if (cmd == TIOCGRS485)
1599 		up_write(&tty->termios_rwsem);
1600 out:
1601 	return ret;
1602 }
1603 
uart_set_ldisc(struct tty_struct * tty)1604 static void uart_set_ldisc(struct tty_struct *tty)
1605 {
1606 	struct uart_state *state = tty->driver_data;
1607 	struct uart_port *uport;
1608 	struct tty_port *port = &state->port;
1609 
1610 	if (!tty_port_initialized(port))
1611 		return;
1612 
1613 	mutex_lock(&state->port.mutex);
1614 	uport = uart_port_check(state);
1615 	if (uport && uport->ops->set_ldisc)
1616 		uport->ops->set_ldisc(uport, &tty->termios);
1617 	mutex_unlock(&state->port.mutex);
1618 }
1619 
uart_set_termios(struct tty_struct * tty,const struct ktermios * old_termios)1620 static void uart_set_termios(struct tty_struct *tty,
1621 			     const struct ktermios *old_termios)
1622 {
1623 	struct uart_state *state = tty->driver_data;
1624 	struct uart_port *uport;
1625 	unsigned int cflag = tty->termios.c_cflag;
1626 	unsigned int iflag_mask = IGNBRK|BRKINT|IGNPAR|PARMRK|INPCK;
1627 	bool sw_changed = false;
1628 
1629 	mutex_lock(&state->port.mutex);
1630 	uport = uart_port_check(state);
1631 	if (!uport)
1632 		goto out;
1633 
1634 	/*
1635 	 * Drivers doing software flow control also need to know
1636 	 * about changes to these input settings.
1637 	 */
1638 	if (uport->flags & UPF_SOFT_FLOW) {
1639 		iflag_mask |= IXANY|IXON|IXOFF;
1640 		sw_changed =
1641 		   tty->termios.c_cc[VSTART] != old_termios->c_cc[VSTART] ||
1642 		   tty->termios.c_cc[VSTOP] != old_termios->c_cc[VSTOP];
1643 	}
1644 
1645 	/*
1646 	 * These are the bits that are used to setup various
1647 	 * flags in the low level driver. We can ignore the Bfoo
1648 	 * bits in c_cflag; c_[io]speed will always be set
1649 	 * appropriately by set_termios() in tty_ioctl.c
1650 	 */
1651 	if ((cflag ^ old_termios->c_cflag) == 0 &&
1652 	    tty->termios.c_ospeed == old_termios->c_ospeed &&
1653 	    tty->termios.c_ispeed == old_termios->c_ispeed &&
1654 	    ((tty->termios.c_iflag ^ old_termios->c_iflag) & iflag_mask) == 0 &&
1655 	    !sw_changed) {
1656 		goto out;
1657 	}
1658 
1659 	uart_change_speed(tty, state, old_termios);
1660 	/* reload cflag from termios; port driver may have overridden flags */
1661 	cflag = tty->termios.c_cflag;
1662 
1663 	/* Handle transition to B0 status */
1664 	if ((old_termios->c_cflag & CBAUD) && !(cflag & CBAUD))
1665 		uart_clear_mctrl(uport, TIOCM_RTS | TIOCM_DTR);
1666 	/* Handle transition away from B0 status */
1667 	else if (!(old_termios->c_cflag & CBAUD) && (cflag & CBAUD)) {
1668 		unsigned int mask = TIOCM_DTR;
1669 
1670 		if (!(cflag & CRTSCTS) || !tty_throttled(tty))
1671 			mask |= TIOCM_RTS;
1672 		uart_set_mctrl(uport, mask);
1673 	}
1674 out:
1675 	mutex_unlock(&state->port.mutex);
1676 }
1677 
1678 /*
1679  * Calls to uart_close() are serialised via the tty_lock in
1680  *   drivers/tty/tty_io.c:tty_release()
1681  *   drivers/tty/tty_io.c:do_tty_hangup()
1682  */
uart_close(struct tty_struct * tty,struct file * filp)1683 static void uart_close(struct tty_struct *tty, struct file *filp)
1684 {
1685 	struct uart_state *state = tty->driver_data;
1686 
1687 	if (!state) {
1688 		struct uart_driver *drv = tty->driver->driver_state;
1689 		struct tty_port *port;
1690 
1691 		state = drv->state + tty->index;
1692 		port = &state->port;
1693 		spin_lock_irq(&port->lock);
1694 		--port->count;
1695 		spin_unlock_irq(&port->lock);
1696 		return;
1697 	}
1698 
1699 	pr_debug("uart_close(%d) called\n", tty->index);
1700 
1701 	tty_port_close(tty->port, tty, filp);
1702 }
1703 
uart_tty_port_shutdown(struct tty_port * port)1704 static void uart_tty_port_shutdown(struct tty_port *port)
1705 {
1706 	struct uart_state *state = container_of(port, struct uart_state, port);
1707 	struct uart_port *uport = uart_port_check(state);
1708 	char *buf;
1709 
1710 	/*
1711 	 * At this point, we stop accepting input.  To do this, we
1712 	 * disable the receive line status interrupts.
1713 	 */
1714 	if (WARN(!uport, "detached port still initialized!\n"))
1715 		return;
1716 
1717 	spin_lock_irq(&uport->lock);
1718 	uport->ops->stop_rx(uport);
1719 	spin_unlock_irq(&uport->lock);
1720 
1721 	uart_port_shutdown(port);
1722 
1723 	/*
1724 	 * It's possible for shutdown to be called after suspend if we get
1725 	 * a DCD drop (hangup) at just the right time.  Clear suspended bit so
1726 	 * we don't try to resume a port that has been shutdown.
1727 	 */
1728 	tty_port_set_suspended(port, 0);
1729 
1730 	/*
1731 	 * Free the transmit buffer.
1732 	 */
1733 	spin_lock_irq(&uport->lock);
1734 	buf = state->xmit.buf;
1735 	state->xmit.buf = NULL;
1736 	spin_unlock_irq(&uport->lock);
1737 
1738 	free_page((unsigned long)buf);
1739 
1740 	uart_change_pm(state, UART_PM_STATE_OFF);
1741 }
1742 
uart_wait_until_sent(struct tty_struct * tty,int timeout)1743 static void uart_wait_until_sent(struct tty_struct *tty, int timeout)
1744 {
1745 	struct uart_state *state = tty->driver_data;
1746 	struct uart_port *port;
1747 	unsigned long char_time, expire, fifo_timeout;
1748 
1749 	port = uart_port_ref(state);
1750 	if (!port)
1751 		return;
1752 
1753 	if (port->type == PORT_UNKNOWN || port->fifosize == 0) {
1754 		uart_port_deref(port);
1755 		return;
1756 	}
1757 
1758 	/*
1759 	 * Set the check interval to be 1/5 of the estimated time to
1760 	 * send a single character, and make it at least 1.  The check
1761 	 * interval should also be less than the timeout.
1762 	 *
1763 	 * Note: we have to use pretty tight timings here to satisfy
1764 	 * the NIST-PCTS.
1765 	 */
1766 	char_time = max(nsecs_to_jiffies(port->frame_time / 5), 1UL);
1767 
1768 	if (timeout && timeout < char_time)
1769 		char_time = timeout;
1770 
1771 	if (!uart_cts_enabled(port)) {
1772 		/*
1773 		 * If the transmitter hasn't cleared in twice the approximate
1774 		 * amount of time to send the entire FIFO, it probably won't
1775 		 * ever clear.  This assumes the UART isn't doing flow
1776 		 * control, which is currently the case.  Hence, if it ever
1777 		 * takes longer than FIFO timeout, this is probably due to a
1778 		 * UART bug of some kind.  So, we clamp the timeout parameter at
1779 		 * 2 * FIFO timeout.
1780 		 */
1781 		fifo_timeout = uart_fifo_timeout(port);
1782 		if (timeout == 0 || timeout > 2 * fifo_timeout)
1783 			timeout = 2 * fifo_timeout;
1784 	}
1785 
1786 	expire = jiffies + timeout;
1787 
1788 	pr_debug("uart_wait_until_sent(%d), jiffies=%lu, expire=%lu...\n",
1789 		port->line, jiffies, expire);
1790 
1791 	/*
1792 	 * Check whether the transmitter is empty every 'char_time'.
1793 	 * 'timeout' / 'expire' give us the maximum amount of time
1794 	 * we wait.
1795 	 */
1796 	while (!port->ops->tx_empty(port)) {
1797 		msleep_interruptible(jiffies_to_msecs(char_time));
1798 		if (signal_pending(current))
1799 			break;
1800 		if (timeout && time_after(jiffies, expire))
1801 			break;
1802 	}
1803 	uart_port_deref(port);
1804 }
1805 
1806 /*
1807  * Calls to uart_hangup() are serialised by the tty_lock in
1808  *   drivers/tty/tty_io.c:do_tty_hangup()
1809  * This runs from a workqueue and can sleep for a _short_ time only.
1810  */
uart_hangup(struct tty_struct * tty)1811 static void uart_hangup(struct tty_struct *tty)
1812 {
1813 	struct uart_state *state = tty->driver_data;
1814 	struct tty_port *port = &state->port;
1815 	struct uart_port *uport;
1816 	unsigned long flags;
1817 
1818 	pr_debug("uart_hangup(%d)\n", tty->index);
1819 
1820 	mutex_lock(&port->mutex);
1821 	uport = uart_port_check(state);
1822 	WARN(!uport, "hangup of detached port!\n");
1823 
1824 	if (tty_port_active(port)) {
1825 		uart_flush_buffer(tty);
1826 		uart_shutdown(tty, state);
1827 		spin_lock_irqsave(&port->lock, flags);
1828 		port->count = 0;
1829 		spin_unlock_irqrestore(&port->lock, flags);
1830 		tty_port_set_active(port, 0);
1831 		tty_port_tty_set(port, NULL);
1832 		if (uport && !uart_console(uport))
1833 			uart_change_pm(state, UART_PM_STATE_OFF);
1834 		wake_up_interruptible(&port->open_wait);
1835 		wake_up_interruptible(&port->delta_msr_wait);
1836 	}
1837 	mutex_unlock(&port->mutex);
1838 }
1839 
1840 /* uport == NULL if uart_port has already been removed */
uart_port_shutdown(struct tty_port * port)1841 static void uart_port_shutdown(struct tty_port *port)
1842 {
1843 	struct uart_state *state = container_of(port, struct uart_state, port);
1844 	struct uart_port *uport = uart_port_check(state);
1845 
1846 	/*
1847 	 * clear delta_msr_wait queue to avoid mem leaks: we may free
1848 	 * the irq here so the queue might never be woken up.  Note
1849 	 * that we won't end up waiting on delta_msr_wait again since
1850 	 * any outstanding file descriptors should be pointing at
1851 	 * hung_up_tty_fops now.
1852 	 */
1853 	wake_up_interruptible(&port->delta_msr_wait);
1854 
1855 	if (uport) {
1856 		/* Free the IRQ and disable the port. */
1857 		uport->ops->shutdown(uport);
1858 
1859 		/* Ensure that the IRQ handler isn't running on another CPU. */
1860 		synchronize_irq(uport->irq);
1861 	}
1862 }
1863 
uart_carrier_raised(struct tty_port * port)1864 static int uart_carrier_raised(struct tty_port *port)
1865 {
1866 	struct uart_state *state = container_of(port, struct uart_state, port);
1867 	struct uart_port *uport;
1868 	int mctrl;
1869 
1870 	uport = uart_port_ref(state);
1871 	/*
1872 	 * Should never observe uport == NULL since checks for hangup should
1873 	 * abort the tty_port_block_til_ready() loop before checking for carrier
1874 	 * raised -- but report carrier raised if it does anyway so open will
1875 	 * continue and not sleep
1876 	 */
1877 	if (WARN_ON(!uport))
1878 		return 1;
1879 	spin_lock_irq(&uport->lock);
1880 	uart_enable_ms(uport);
1881 	mctrl = uport->ops->get_mctrl(uport);
1882 	spin_unlock_irq(&uport->lock);
1883 	uart_port_deref(uport);
1884 	if (mctrl & TIOCM_CAR)
1885 		return 1;
1886 	return 0;
1887 }
1888 
uart_dtr_rts(struct tty_port * port,int raise)1889 static void uart_dtr_rts(struct tty_port *port, int raise)
1890 {
1891 	struct uart_state *state = container_of(port, struct uart_state, port);
1892 	struct uart_port *uport;
1893 
1894 	uport = uart_port_ref(state);
1895 	if (!uport)
1896 		return;
1897 	uart_port_dtr_rts(uport, raise);
1898 	uart_port_deref(uport);
1899 }
1900 
uart_install(struct tty_driver * driver,struct tty_struct * tty)1901 static int uart_install(struct tty_driver *driver, struct tty_struct *tty)
1902 {
1903 	struct uart_driver *drv = driver->driver_state;
1904 	struct uart_state *state = drv->state + tty->index;
1905 
1906 	tty->driver_data = state;
1907 
1908 	return tty_standard_install(driver, tty);
1909 }
1910 
1911 /*
1912  * Calls to uart_open are serialised by the tty_lock in
1913  *   drivers/tty/tty_io.c:tty_open()
1914  * Note that if this fails, then uart_close() _will_ be called.
1915  *
1916  * In time, we want to scrap the "opening nonpresent ports"
1917  * behaviour and implement an alternative way for setserial
1918  * to set base addresses/ports/types.  This will allow us to
1919  * get rid of a certain amount of extra tests.
1920  */
uart_open(struct tty_struct * tty,struct file * filp)1921 static int uart_open(struct tty_struct *tty, struct file *filp)
1922 {
1923 	struct uart_state *state = tty->driver_data;
1924 	int retval;
1925 
1926 	retval = tty_port_open(&state->port, tty, filp);
1927 	if (retval > 0)
1928 		retval = 0;
1929 
1930 	return retval;
1931 }
1932 
uart_port_activate(struct tty_port * port,struct tty_struct * tty)1933 static int uart_port_activate(struct tty_port *port, struct tty_struct *tty)
1934 {
1935 	struct uart_state *state = container_of(port, struct uart_state, port);
1936 	struct uart_port *uport;
1937 	int ret;
1938 
1939 	uport = uart_port_check(state);
1940 	if (!uport || uport->flags & UPF_DEAD)
1941 		return -ENXIO;
1942 
1943 	/*
1944 	 * Start up the serial port.
1945 	 */
1946 	ret = uart_startup(tty, state, 0);
1947 	if (ret > 0)
1948 		tty_port_set_active(port, 1);
1949 
1950 	return ret;
1951 }
1952 
uart_type(struct uart_port * port)1953 static const char *uart_type(struct uart_port *port)
1954 {
1955 	const char *str = NULL;
1956 
1957 	if (port->ops->type)
1958 		str = port->ops->type(port);
1959 
1960 	if (!str)
1961 		str = "unknown";
1962 
1963 	return str;
1964 }
1965 
1966 #ifdef CONFIG_PROC_FS
1967 
uart_line_info(struct seq_file * m,struct uart_driver * drv,int i)1968 static void uart_line_info(struct seq_file *m, struct uart_driver *drv, int i)
1969 {
1970 	struct uart_state *state = drv->state + i;
1971 	struct tty_port *port = &state->port;
1972 	enum uart_pm_state pm_state;
1973 	struct uart_port *uport;
1974 	char stat_buf[32];
1975 	unsigned int status;
1976 	int mmio;
1977 
1978 	mutex_lock(&port->mutex);
1979 	uport = uart_port_check(state);
1980 	if (!uport)
1981 		goto out;
1982 
1983 	mmio = uport->iotype >= UPIO_MEM;
1984 	seq_printf(m, "%d: uart:%s %s%08llX irq:%d",
1985 			uport->line, uart_type(uport),
1986 			mmio ? "mmio:0x" : "port:",
1987 			mmio ? (unsigned long long)uport->mapbase
1988 			     : (unsigned long long)uport->iobase,
1989 			uport->irq);
1990 
1991 	if (uport->type == PORT_UNKNOWN) {
1992 		seq_putc(m, '\n');
1993 		goto out;
1994 	}
1995 
1996 	if (capable(CAP_SYS_ADMIN)) {
1997 		pm_state = state->pm_state;
1998 		if (pm_state != UART_PM_STATE_ON)
1999 			uart_change_pm(state, UART_PM_STATE_ON);
2000 		spin_lock_irq(&uport->lock);
2001 		status = uport->ops->get_mctrl(uport);
2002 		spin_unlock_irq(&uport->lock);
2003 		if (pm_state != UART_PM_STATE_ON)
2004 			uart_change_pm(state, pm_state);
2005 
2006 		seq_printf(m, " tx:%d rx:%d",
2007 				uport->icount.tx, uport->icount.rx);
2008 		if (uport->icount.frame)
2009 			seq_printf(m, " fe:%d",	uport->icount.frame);
2010 		if (uport->icount.parity)
2011 			seq_printf(m, " pe:%d",	uport->icount.parity);
2012 		if (uport->icount.brk)
2013 			seq_printf(m, " brk:%d", uport->icount.brk);
2014 		if (uport->icount.overrun)
2015 			seq_printf(m, " oe:%d", uport->icount.overrun);
2016 		if (uport->icount.buf_overrun)
2017 			seq_printf(m, " bo:%d", uport->icount.buf_overrun);
2018 
2019 #define INFOBIT(bit, str) \
2020 	if (uport->mctrl & (bit)) \
2021 		strncat(stat_buf, (str), sizeof(stat_buf) - \
2022 			strlen(stat_buf) - 2)
2023 #define STATBIT(bit, str) \
2024 	if (status & (bit)) \
2025 		strncat(stat_buf, (str), sizeof(stat_buf) - \
2026 		       strlen(stat_buf) - 2)
2027 
2028 		stat_buf[0] = '\0';
2029 		stat_buf[1] = '\0';
2030 		INFOBIT(TIOCM_RTS, "|RTS");
2031 		STATBIT(TIOCM_CTS, "|CTS");
2032 		INFOBIT(TIOCM_DTR, "|DTR");
2033 		STATBIT(TIOCM_DSR, "|DSR");
2034 		STATBIT(TIOCM_CAR, "|CD");
2035 		STATBIT(TIOCM_RNG, "|RI");
2036 		if (stat_buf[0])
2037 			stat_buf[0] = ' ';
2038 
2039 		seq_puts(m, stat_buf);
2040 	}
2041 	seq_putc(m, '\n');
2042 #undef STATBIT
2043 #undef INFOBIT
2044 out:
2045 	mutex_unlock(&port->mutex);
2046 }
2047 
uart_proc_show(struct seq_file * m,void * v)2048 static int uart_proc_show(struct seq_file *m, void *v)
2049 {
2050 	struct tty_driver *ttydrv = m->private;
2051 	struct uart_driver *drv = ttydrv->driver_state;
2052 	int i;
2053 
2054 	seq_printf(m, "serinfo:1.0 driver%s%s revision:%s\n", "", "", "");
2055 	for (i = 0; i < drv->nr; i++)
2056 		uart_line_info(m, drv, i);
2057 	return 0;
2058 }
2059 #endif
2060 
uart_port_spin_lock_init(struct uart_port * port)2061 static void uart_port_spin_lock_init(struct uart_port *port)
2062 {
2063 	spin_lock_init(&port->lock);
2064 	lockdep_set_class(&port->lock, &port_lock_key);
2065 }
2066 
2067 #if defined(CONFIG_SERIAL_CORE_CONSOLE) || defined(CONFIG_CONSOLE_POLL)
2068 /**
2069  * uart_console_write - write a console message to a serial port
2070  * @port: the port to write the message
2071  * @s: array of characters
2072  * @count: number of characters in string to write
2073  * @putchar: function to write character to port
2074  */
uart_console_write(struct uart_port * port,const char * s,unsigned int count,void (* putchar)(struct uart_port *,unsigned char))2075 void uart_console_write(struct uart_port *port, const char *s,
2076 			unsigned int count,
2077 			void (*putchar)(struct uart_port *, unsigned char))
2078 {
2079 	unsigned int i;
2080 
2081 	for (i = 0; i < count; i++, s++) {
2082 		if (*s == '\n')
2083 			putchar(port, '\r');
2084 		putchar(port, *s);
2085 	}
2086 }
2087 EXPORT_SYMBOL_GPL(uart_console_write);
2088 
2089 /**
2090  * uart_get_console - get uart port for console
2091  * @ports: ports to search in
2092  * @nr: number of @ports
2093  * @co: console to search for
2094  * Returns: uart_port for the console @co
2095  *
2096  * Check whether an invalid uart number has been specified (as @co->index), and
2097  * if so, search for the first available port that does have console support.
2098  */
2099 struct uart_port * __init
uart_get_console(struct uart_port * ports,int nr,struct console * co)2100 uart_get_console(struct uart_port *ports, int nr, struct console *co)
2101 {
2102 	int idx = co->index;
2103 
2104 	if (idx < 0 || idx >= nr || (ports[idx].iobase == 0 &&
2105 				     ports[idx].membase == NULL))
2106 		for (idx = 0; idx < nr; idx++)
2107 			if (ports[idx].iobase != 0 ||
2108 			    ports[idx].membase != NULL)
2109 				break;
2110 
2111 	co->index = idx;
2112 
2113 	return ports + idx;
2114 }
2115 
2116 /**
2117  * uart_parse_earlycon - Parse earlycon options
2118  * @p:	     ptr to 2nd field (ie., just beyond '<name>,')
2119  * @iotype:  ptr for decoded iotype (out)
2120  * @addr:    ptr for decoded mapbase/iobase (out)
2121  * @options: ptr for <options> field; %NULL if not present (out)
2122  *
2123  * Decodes earlycon kernel command line parameters of the form:
2124  *  * earlycon=<name>,io|mmio|mmio16|mmio32|mmio32be|mmio32native,<addr>,<options>
2125  *  * console=<name>,io|mmio|mmio16|mmio32|mmio32be|mmio32native,<addr>,<options>
2126  *
2127  * The optional form:
2128  *  * earlycon=<name>,0x<addr>,<options>
2129  *  * console=<name>,0x<addr>,<options>
2130  *
2131  * is also accepted; the returned @iotype will be %UPIO_MEM.
2132  *
2133  * Returns: 0 on success or -%EINVAL on failure
2134  */
uart_parse_earlycon(char * p,unsigned char * iotype,resource_size_t * addr,char ** options)2135 int uart_parse_earlycon(char *p, unsigned char *iotype, resource_size_t *addr,
2136 			char **options)
2137 {
2138 	if (strncmp(p, "mmio,", 5) == 0) {
2139 		*iotype = UPIO_MEM;
2140 		p += 5;
2141 	} else if (strncmp(p, "mmio16,", 7) == 0) {
2142 		*iotype = UPIO_MEM16;
2143 		p += 7;
2144 	} else if (strncmp(p, "mmio32,", 7) == 0) {
2145 		*iotype = UPIO_MEM32;
2146 		p += 7;
2147 	} else if (strncmp(p, "mmio32be,", 9) == 0) {
2148 		*iotype = UPIO_MEM32BE;
2149 		p += 9;
2150 	} else if (strncmp(p, "mmio32native,", 13) == 0) {
2151 		*iotype = IS_ENABLED(CONFIG_CPU_BIG_ENDIAN) ?
2152 			UPIO_MEM32BE : UPIO_MEM32;
2153 		p += 13;
2154 	} else if (strncmp(p, "io,", 3) == 0) {
2155 		*iotype = UPIO_PORT;
2156 		p += 3;
2157 	} else if (strncmp(p, "0x", 2) == 0) {
2158 		*iotype = UPIO_MEM;
2159 	} else {
2160 		return -EINVAL;
2161 	}
2162 
2163 	/*
2164 	 * Before you replace it with kstrtoull(), think about options separator
2165 	 * (',') it will not tolerate
2166 	 */
2167 	*addr = simple_strtoull(p, NULL, 0);
2168 	p = strchr(p, ',');
2169 	if (p)
2170 		p++;
2171 
2172 	*options = p;
2173 	return 0;
2174 }
2175 EXPORT_SYMBOL_GPL(uart_parse_earlycon);
2176 
2177 /**
2178  * uart_parse_options - Parse serial port baud/parity/bits/flow control.
2179  * @options: pointer to option string
2180  * @baud: pointer to an 'int' variable for the baud rate.
2181  * @parity: pointer to an 'int' variable for the parity.
2182  * @bits: pointer to an 'int' variable for the number of data bits.
2183  * @flow: pointer to an 'int' variable for the flow control character.
2184  *
2185  * uart_parse_options() decodes a string containing the serial console
2186  * options. The format of the string is <baud><parity><bits><flow>,
2187  * eg: 115200n8r
2188  */
2189 void
uart_parse_options(const char * options,int * baud,int * parity,int * bits,int * flow)2190 uart_parse_options(const char *options, int *baud, int *parity,
2191 		   int *bits, int *flow)
2192 {
2193 	const char *s = options;
2194 
2195 	*baud = simple_strtoul(s, NULL, 10);
2196 	while (*s >= '0' && *s <= '9')
2197 		s++;
2198 	if (*s)
2199 		*parity = *s++;
2200 	if (*s)
2201 		*bits = *s++ - '0';
2202 	if (*s)
2203 		*flow = *s;
2204 }
2205 EXPORT_SYMBOL_GPL(uart_parse_options);
2206 
2207 /**
2208  * uart_set_options - setup the serial console parameters
2209  * @port: pointer to the serial ports uart_port structure
2210  * @co: console pointer
2211  * @baud: baud rate
2212  * @parity: parity character - 'n' (none), 'o' (odd), 'e' (even)
2213  * @bits: number of data bits
2214  * @flow: flow control character - 'r' (rts)
2215  */
2216 int
uart_set_options(struct uart_port * port,struct console * co,int baud,int parity,int bits,int flow)2217 uart_set_options(struct uart_port *port, struct console *co,
2218 		 int baud, int parity, int bits, int flow)
2219 {
2220 	struct ktermios termios;
2221 	static struct ktermios dummy;
2222 
2223 	/*
2224 	 * Ensure that the serial-console lock is initialised early.
2225 	 *
2226 	 * Note that the console-enabled check is needed because of kgdboc,
2227 	 * which can end up calling uart_set_options() for an already enabled
2228 	 * console via tty_find_polling_driver() and uart_poll_init().
2229 	 */
2230 	if (!uart_console_enabled(port) && !port->console_reinit)
2231 		uart_port_spin_lock_init(port);
2232 
2233 	memset(&termios, 0, sizeof(struct ktermios));
2234 
2235 	termios.c_cflag |= CREAD | HUPCL | CLOCAL;
2236 	tty_termios_encode_baud_rate(&termios, baud, baud);
2237 
2238 	if (bits == 7)
2239 		termios.c_cflag |= CS7;
2240 	else
2241 		termios.c_cflag |= CS8;
2242 
2243 	switch (parity) {
2244 	case 'o': case 'O':
2245 		termios.c_cflag |= PARODD;
2246 		fallthrough;
2247 	case 'e': case 'E':
2248 		termios.c_cflag |= PARENB;
2249 		break;
2250 	}
2251 
2252 	if (flow == 'r')
2253 		termios.c_cflag |= CRTSCTS;
2254 
2255 	/*
2256 	 * some uarts on other side don't support no flow control.
2257 	 * So we set * DTR in host uart to make them happy
2258 	 */
2259 	port->mctrl |= TIOCM_DTR;
2260 
2261 	port->ops->set_termios(port, &termios, &dummy);
2262 	/*
2263 	 * Allow the setting of the UART parameters with a NULL console
2264 	 * too:
2265 	 */
2266 	if (co) {
2267 		co->cflag = termios.c_cflag;
2268 		co->ispeed = termios.c_ispeed;
2269 		co->ospeed = termios.c_ospeed;
2270 	}
2271 
2272 	return 0;
2273 }
2274 EXPORT_SYMBOL_GPL(uart_set_options);
2275 #endif /* CONFIG_SERIAL_CORE_CONSOLE */
2276 
2277 /**
2278  * uart_change_pm - set power state of the port
2279  *
2280  * @state: port descriptor
2281  * @pm_state: new state
2282  *
2283  * Locking: port->mutex has to be held
2284  */
uart_change_pm(struct uart_state * state,enum uart_pm_state pm_state)2285 static void uart_change_pm(struct uart_state *state,
2286 			   enum uart_pm_state pm_state)
2287 {
2288 	struct uart_port *port = uart_port_check(state);
2289 
2290 	if (state->pm_state != pm_state) {
2291 		if (port && port->ops->pm)
2292 			port->ops->pm(port, pm_state, state->pm_state);
2293 		state->pm_state = pm_state;
2294 	}
2295 }
2296 
2297 struct uart_match {
2298 	struct uart_port *port;
2299 	struct uart_driver *driver;
2300 };
2301 
serial_match_port(struct device * dev,void * data)2302 static int serial_match_port(struct device *dev, void *data)
2303 {
2304 	struct uart_match *match = data;
2305 	struct tty_driver *tty_drv = match->driver->tty_driver;
2306 	dev_t devt = MKDEV(tty_drv->major, tty_drv->minor_start) +
2307 		match->port->line;
2308 
2309 	return dev->devt == devt; /* Actually, only one tty per port */
2310 }
2311 
uart_suspend_port(struct uart_driver * drv,struct uart_port * uport)2312 int uart_suspend_port(struct uart_driver *drv, struct uart_port *uport)
2313 {
2314 	struct uart_state *state = drv->state + uport->line;
2315 	struct tty_port *port = &state->port;
2316 	struct device *tty_dev;
2317 	struct uart_match match = {uport, drv};
2318 
2319 	mutex_lock(&port->mutex);
2320 
2321 	tty_dev = device_find_child(uport->dev, &match, serial_match_port);
2322 	if (tty_dev && device_may_wakeup(tty_dev)) {
2323 		enable_irq_wake(uport->irq);
2324 		put_device(tty_dev);
2325 		mutex_unlock(&port->mutex);
2326 		return 0;
2327 	}
2328 	put_device(tty_dev);
2329 
2330 	/*
2331 	 * Nothing to do if the console is not suspending
2332 	 * except stop_rx to prevent any asynchronous data
2333 	 * over RX line. However ensure that we will be
2334 	 * able to Re-start_rx later.
2335 	 */
2336 	if (!console_suspend_enabled && uart_console(uport)) {
2337 		if (uport->ops->start_rx)
2338 			uport->ops->stop_rx(uport);
2339 		goto unlock;
2340 	}
2341 
2342 	uport->suspended = 1;
2343 
2344 	if (tty_port_initialized(port)) {
2345 		const struct uart_ops *ops = uport->ops;
2346 		int tries;
2347 		unsigned int mctrl;
2348 
2349 		tty_port_set_suspended(port, 1);
2350 		tty_port_set_initialized(port, 0);
2351 
2352 		spin_lock_irq(&uport->lock);
2353 		ops->stop_tx(uport);
2354 		if (!(uport->rs485.flags & SER_RS485_ENABLED))
2355 			ops->set_mctrl(uport, 0);
2356 		/* save mctrl so it can be restored on resume */
2357 		mctrl = uport->mctrl;
2358 		uport->mctrl = 0;
2359 		ops->stop_rx(uport);
2360 		spin_unlock_irq(&uport->lock);
2361 
2362 		/*
2363 		 * Wait for the transmitter to empty.
2364 		 */
2365 		for (tries = 3; !ops->tx_empty(uport) && tries; tries--)
2366 			msleep(10);
2367 		if (!tries)
2368 			dev_err(uport->dev, "%s: Unable to drain transmitter\n",
2369 				uport->name);
2370 
2371 		ops->shutdown(uport);
2372 		uport->mctrl = mctrl;
2373 	}
2374 
2375 	/*
2376 	 * Disable the console device before suspending.
2377 	 */
2378 	if (uart_console(uport))
2379 		console_stop(uport->cons);
2380 
2381 	uart_change_pm(state, UART_PM_STATE_OFF);
2382 unlock:
2383 	mutex_unlock(&port->mutex);
2384 
2385 	return 0;
2386 }
2387 EXPORT_SYMBOL(uart_suspend_port);
2388 
uart_resume_port(struct uart_driver * drv,struct uart_port * uport)2389 int uart_resume_port(struct uart_driver *drv, struct uart_port *uport)
2390 {
2391 	struct uart_state *state = drv->state + uport->line;
2392 	struct tty_port *port = &state->port;
2393 	struct device *tty_dev;
2394 	struct uart_match match = {uport, drv};
2395 	struct ktermios termios;
2396 
2397 	mutex_lock(&port->mutex);
2398 
2399 	tty_dev = device_find_child(uport->dev, &match, serial_match_port);
2400 	if (!uport->suspended && device_may_wakeup(tty_dev)) {
2401 		if (irqd_is_wakeup_set(irq_get_irq_data((uport->irq))))
2402 			disable_irq_wake(uport->irq);
2403 		put_device(tty_dev);
2404 		mutex_unlock(&port->mutex);
2405 		return 0;
2406 	}
2407 	put_device(tty_dev);
2408 	uport->suspended = 0;
2409 
2410 	/*
2411 	 * Re-enable the console device after suspending.
2412 	 */
2413 	if (uart_console(uport)) {
2414 		/*
2415 		 * First try to use the console cflag setting.
2416 		 */
2417 		memset(&termios, 0, sizeof(struct ktermios));
2418 		termios.c_cflag = uport->cons->cflag;
2419 		termios.c_ispeed = uport->cons->ispeed;
2420 		termios.c_ospeed = uport->cons->ospeed;
2421 
2422 		/*
2423 		 * If that's unset, use the tty termios setting.
2424 		 */
2425 		if (port->tty && termios.c_cflag == 0)
2426 			termios = port->tty->termios;
2427 
2428 		if (console_suspend_enabled)
2429 			uart_change_pm(state, UART_PM_STATE_ON);
2430 		uport->ops->set_termios(uport, &termios, NULL);
2431 		if (!console_suspend_enabled && uport->ops->start_rx)
2432 			uport->ops->start_rx(uport);
2433 		if (console_suspend_enabled)
2434 			console_start(uport->cons);
2435 	}
2436 
2437 	if (tty_port_suspended(port)) {
2438 		const struct uart_ops *ops = uport->ops;
2439 		int ret;
2440 
2441 		uart_change_pm(state, UART_PM_STATE_ON);
2442 		spin_lock_irq(&uport->lock);
2443 		if (!(uport->rs485.flags & SER_RS485_ENABLED))
2444 			ops->set_mctrl(uport, 0);
2445 		spin_unlock_irq(&uport->lock);
2446 		if (console_suspend_enabled || !uart_console(uport)) {
2447 			/* Protected by port mutex for now */
2448 			struct tty_struct *tty = port->tty;
2449 
2450 			ret = ops->startup(uport);
2451 			if (ret == 0) {
2452 				if (tty)
2453 					uart_change_speed(tty, state, NULL);
2454 				spin_lock_irq(&uport->lock);
2455 				if (!(uport->rs485.flags & SER_RS485_ENABLED))
2456 					ops->set_mctrl(uport, uport->mctrl);
2457 				else
2458 					uart_rs485_config(uport);
2459 				ops->start_tx(uport);
2460 				spin_unlock_irq(&uport->lock);
2461 				tty_port_set_initialized(port, 1);
2462 			} else {
2463 				/*
2464 				 * Failed to resume - maybe hardware went away?
2465 				 * Clear the "initialized" flag so we won't try
2466 				 * to call the low level drivers shutdown method.
2467 				 */
2468 				uart_shutdown(tty, state);
2469 			}
2470 		}
2471 
2472 		tty_port_set_suspended(port, 0);
2473 	}
2474 
2475 	mutex_unlock(&port->mutex);
2476 
2477 	return 0;
2478 }
2479 EXPORT_SYMBOL(uart_resume_port);
2480 
2481 static inline void
uart_report_port(struct uart_driver * drv,struct uart_port * port)2482 uart_report_port(struct uart_driver *drv, struct uart_port *port)
2483 {
2484 	char address[64];
2485 
2486 	switch (port->iotype) {
2487 	case UPIO_PORT:
2488 		snprintf(address, sizeof(address), "I/O 0x%lx", port->iobase);
2489 		break;
2490 	case UPIO_HUB6:
2491 		snprintf(address, sizeof(address),
2492 			 "I/O 0x%lx offset 0x%x", port->iobase, port->hub6);
2493 		break;
2494 	case UPIO_MEM:
2495 	case UPIO_MEM16:
2496 	case UPIO_MEM32:
2497 	case UPIO_MEM32BE:
2498 	case UPIO_AU:
2499 	case UPIO_TSI:
2500 		snprintf(address, sizeof(address),
2501 			 "MMIO 0x%llx", (unsigned long long)port->mapbase);
2502 		break;
2503 	default:
2504 		strscpy(address, "*unknown*", sizeof(address));
2505 		break;
2506 	}
2507 
2508 	pr_info("%s%s%s at %s (irq = %d, base_baud = %d) is a %s\n",
2509 	       port->dev ? dev_name(port->dev) : "",
2510 	       port->dev ? ": " : "",
2511 	       port->name,
2512 	       address, port->irq, port->uartclk / 16, uart_type(port));
2513 
2514 	/* The magic multiplier feature is a bit obscure, so report it too.  */
2515 	if (port->flags & UPF_MAGIC_MULTIPLIER)
2516 		pr_info("%s%s%s extra baud rates supported: %d, %d",
2517 			port->dev ? dev_name(port->dev) : "",
2518 			port->dev ? ": " : "",
2519 			port->name,
2520 			port->uartclk / 8, port->uartclk / 4);
2521 }
2522 
2523 static void
uart_configure_port(struct uart_driver * drv,struct uart_state * state,struct uart_port * port)2524 uart_configure_port(struct uart_driver *drv, struct uart_state *state,
2525 		    struct uart_port *port)
2526 {
2527 	unsigned int flags;
2528 
2529 	/*
2530 	 * If there isn't a port here, don't do anything further.
2531 	 */
2532 	if (!port->iobase && !port->mapbase && !port->membase)
2533 		return;
2534 
2535 	/*
2536 	 * Now do the auto configuration stuff.  Note that config_port
2537 	 * is expected to claim the resources and map the port for us.
2538 	 */
2539 	flags = 0;
2540 	if (port->flags & UPF_AUTO_IRQ)
2541 		flags |= UART_CONFIG_IRQ;
2542 	if (port->flags & UPF_BOOT_AUTOCONF) {
2543 		if (!(port->flags & UPF_FIXED_TYPE)) {
2544 			port->type = PORT_UNKNOWN;
2545 			flags |= UART_CONFIG_TYPE;
2546 		}
2547 		port->ops->config_port(port, flags);
2548 	}
2549 
2550 	if (port->type != PORT_UNKNOWN) {
2551 		unsigned long flags;
2552 
2553 		uart_report_port(drv, port);
2554 
2555 		/* Power up port for set_mctrl() */
2556 		uart_change_pm(state, UART_PM_STATE_ON);
2557 
2558 		/*
2559 		 * Ensure that the modem control lines are de-activated.
2560 		 * keep the DTR setting that is set in uart_set_options()
2561 		 * We probably don't need a spinlock around this, but
2562 		 */
2563 		spin_lock_irqsave(&port->lock, flags);
2564 		port->mctrl &= TIOCM_DTR;
2565 		if (!(port->rs485.flags & SER_RS485_ENABLED))
2566 			port->ops->set_mctrl(port, port->mctrl);
2567 		else
2568 			uart_rs485_config(port);
2569 		spin_unlock_irqrestore(&port->lock, flags);
2570 
2571 		/*
2572 		 * If this driver supports console, and it hasn't been
2573 		 * successfully registered yet, try to re-register it.
2574 		 * It may be that the port was not available.
2575 		 */
2576 		if (port->cons && !(port->cons->flags & CON_ENABLED))
2577 			register_console(port->cons);
2578 
2579 		/*
2580 		 * Power down all ports by default, except the
2581 		 * console if we have one.
2582 		 */
2583 		if (!uart_console(port))
2584 			uart_change_pm(state, UART_PM_STATE_OFF);
2585 	}
2586 }
2587 
2588 #ifdef CONFIG_CONSOLE_POLL
2589 
uart_poll_init(struct tty_driver * driver,int line,char * options)2590 static int uart_poll_init(struct tty_driver *driver, int line, char *options)
2591 {
2592 	struct uart_driver *drv = driver->driver_state;
2593 	struct uart_state *state = drv->state + line;
2594 	struct tty_port *tport;
2595 	struct uart_port *port;
2596 	int baud = 9600;
2597 	int bits = 8;
2598 	int parity = 'n';
2599 	int flow = 'n';
2600 	int ret = 0;
2601 
2602 	tport = &state->port;
2603 	mutex_lock(&tport->mutex);
2604 
2605 	port = uart_port_check(state);
2606 	if (!port || !(port->ops->poll_get_char && port->ops->poll_put_char)) {
2607 		ret = -1;
2608 		goto out;
2609 	}
2610 
2611 	if (port->ops->poll_init) {
2612 		/*
2613 		 * We don't set initialized as we only initialized the hw,
2614 		 * e.g. state->xmit is still uninitialized.
2615 		 */
2616 		if (!tty_port_initialized(tport))
2617 			ret = port->ops->poll_init(port);
2618 	}
2619 
2620 	if (!ret && options) {
2621 		uart_parse_options(options, &baud, &parity, &bits, &flow);
2622 		ret = uart_set_options(port, NULL, baud, parity, bits, flow);
2623 	}
2624 out:
2625 	mutex_unlock(&tport->mutex);
2626 	return ret;
2627 }
2628 
uart_poll_get_char(struct tty_driver * driver,int line)2629 static int uart_poll_get_char(struct tty_driver *driver, int line)
2630 {
2631 	struct uart_driver *drv = driver->driver_state;
2632 	struct uart_state *state = drv->state + line;
2633 	struct uart_port *port;
2634 	int ret = -1;
2635 
2636 	port = uart_port_ref(state);
2637 	if (port) {
2638 		ret = port->ops->poll_get_char(port);
2639 		uart_port_deref(port);
2640 	}
2641 
2642 	return ret;
2643 }
2644 
uart_poll_put_char(struct tty_driver * driver,int line,char ch)2645 static void uart_poll_put_char(struct tty_driver *driver, int line, char ch)
2646 {
2647 	struct uart_driver *drv = driver->driver_state;
2648 	struct uart_state *state = drv->state + line;
2649 	struct uart_port *port;
2650 
2651 	port = uart_port_ref(state);
2652 	if (!port)
2653 		return;
2654 
2655 	if (ch == '\n')
2656 		port->ops->poll_put_char(port, '\r');
2657 	port->ops->poll_put_char(port, ch);
2658 	uart_port_deref(port);
2659 }
2660 #endif
2661 
2662 static const struct tty_operations uart_ops = {
2663 	.install	= uart_install,
2664 	.open		= uart_open,
2665 	.close		= uart_close,
2666 	.write		= uart_write,
2667 	.put_char	= uart_put_char,
2668 	.flush_chars	= uart_flush_chars,
2669 	.write_room	= uart_write_room,
2670 	.chars_in_buffer= uart_chars_in_buffer,
2671 	.flush_buffer	= uart_flush_buffer,
2672 	.ioctl		= uart_ioctl,
2673 	.throttle	= uart_throttle,
2674 	.unthrottle	= uart_unthrottle,
2675 	.send_xchar	= uart_send_xchar,
2676 	.set_termios	= uart_set_termios,
2677 	.set_ldisc	= uart_set_ldisc,
2678 	.stop		= uart_stop,
2679 	.start		= uart_start,
2680 	.hangup		= uart_hangup,
2681 	.break_ctl	= uart_break_ctl,
2682 	.wait_until_sent= uart_wait_until_sent,
2683 #ifdef CONFIG_PROC_FS
2684 	.proc_show	= uart_proc_show,
2685 #endif
2686 	.tiocmget	= uart_tiocmget,
2687 	.tiocmset	= uart_tiocmset,
2688 	.set_serial	= uart_set_info_user,
2689 	.get_serial	= uart_get_info_user,
2690 	.get_icount	= uart_get_icount,
2691 #ifdef CONFIG_CONSOLE_POLL
2692 	.poll_init	= uart_poll_init,
2693 	.poll_get_char	= uart_poll_get_char,
2694 	.poll_put_char	= uart_poll_put_char,
2695 #endif
2696 };
2697 
2698 static const struct tty_port_operations uart_port_ops = {
2699 	.carrier_raised = uart_carrier_raised,
2700 	.dtr_rts	= uart_dtr_rts,
2701 	.activate	= uart_port_activate,
2702 	.shutdown	= uart_tty_port_shutdown,
2703 };
2704 
2705 /**
2706  * uart_register_driver - register a driver with the uart core layer
2707  * @drv: low level driver structure
2708  *
2709  * Register a uart driver with the core driver. We in turn register with the
2710  * tty layer, and initialise the core driver per-port state.
2711  *
2712  * We have a proc file in /proc/tty/driver which is named after the normal
2713  * driver.
2714  *
2715  * @drv->port should be %NULL, and the per-port structures should be registered
2716  * using uart_add_one_port() after this call has succeeded.
2717  *
2718  * Locking: none, Interrupts: enabled
2719  */
uart_register_driver(struct uart_driver * drv)2720 int uart_register_driver(struct uart_driver *drv)
2721 {
2722 	struct tty_driver *normal;
2723 	int i, retval = -ENOMEM;
2724 
2725 	BUG_ON(drv->state);
2726 
2727 	/*
2728 	 * Maybe we should be using a slab cache for this, especially if
2729 	 * we have a large number of ports to handle.
2730 	 */
2731 	drv->state = kcalloc(drv->nr, sizeof(struct uart_state), GFP_KERNEL);
2732 	if (!drv->state)
2733 		goto out;
2734 
2735 	normal = tty_alloc_driver(drv->nr, TTY_DRIVER_REAL_RAW |
2736 			TTY_DRIVER_DYNAMIC_DEV);
2737 	if (IS_ERR(normal)) {
2738 		retval = PTR_ERR(normal);
2739 		goto out_kfree;
2740 	}
2741 
2742 	drv->tty_driver = normal;
2743 
2744 	normal->driver_name	= drv->driver_name;
2745 	normal->name		= drv->dev_name;
2746 	normal->major		= drv->major;
2747 	normal->minor_start	= drv->minor;
2748 	normal->type		= TTY_DRIVER_TYPE_SERIAL;
2749 	normal->subtype		= SERIAL_TYPE_NORMAL;
2750 	normal->init_termios	= tty_std_termios;
2751 	normal->init_termios.c_cflag = B9600 | CS8 | CREAD | HUPCL | CLOCAL;
2752 	normal->init_termios.c_ispeed = normal->init_termios.c_ospeed = 9600;
2753 	normal->driver_state    = drv;
2754 	tty_set_operations(normal, &uart_ops);
2755 
2756 	/*
2757 	 * Initialise the UART state(s).
2758 	 */
2759 	for (i = 0; i < drv->nr; i++) {
2760 		struct uart_state *state = drv->state + i;
2761 		struct tty_port *port = &state->port;
2762 
2763 		tty_port_init(port);
2764 		port->ops = &uart_port_ops;
2765 	}
2766 
2767 	retval = tty_register_driver(normal);
2768 	if (retval >= 0)
2769 		return retval;
2770 
2771 	for (i = 0; i < drv->nr; i++)
2772 		tty_port_destroy(&drv->state[i].port);
2773 	tty_driver_kref_put(normal);
2774 out_kfree:
2775 	kfree(drv->state);
2776 out:
2777 	return retval;
2778 }
2779 EXPORT_SYMBOL(uart_register_driver);
2780 
2781 /**
2782  * uart_unregister_driver - remove a driver from the uart core layer
2783  * @drv: low level driver structure
2784  *
2785  * Remove all references to a driver from the core driver. The low level
2786  * driver must have removed all its ports via the uart_remove_one_port() if it
2787  * registered them with uart_add_one_port(). (I.e. @drv->port is %NULL.)
2788  *
2789  * Locking: none, Interrupts: enabled
2790  */
uart_unregister_driver(struct uart_driver * drv)2791 void uart_unregister_driver(struct uart_driver *drv)
2792 {
2793 	struct tty_driver *p = drv->tty_driver;
2794 	unsigned int i;
2795 
2796 	tty_unregister_driver(p);
2797 	tty_driver_kref_put(p);
2798 	for (i = 0; i < drv->nr; i++)
2799 		tty_port_destroy(&drv->state[i].port);
2800 	kfree(drv->state);
2801 	drv->state = NULL;
2802 	drv->tty_driver = NULL;
2803 }
2804 EXPORT_SYMBOL(uart_unregister_driver);
2805 
uart_console_device(struct console * co,int * index)2806 struct tty_driver *uart_console_device(struct console *co, int *index)
2807 {
2808 	struct uart_driver *p = co->data;
2809 	*index = co->index;
2810 	return p->tty_driver;
2811 }
2812 EXPORT_SYMBOL_GPL(uart_console_device);
2813 
uartclk_show(struct device * dev,struct device_attribute * attr,char * buf)2814 static ssize_t uartclk_show(struct device *dev,
2815 	struct device_attribute *attr, char *buf)
2816 {
2817 	struct serial_struct tmp;
2818 	struct tty_port *port = dev_get_drvdata(dev);
2819 
2820 	uart_get_info(port, &tmp);
2821 	return sprintf(buf, "%d\n", tmp.baud_base * 16);
2822 }
2823 
type_show(struct device * dev,struct device_attribute * attr,char * buf)2824 static ssize_t type_show(struct device *dev,
2825 	struct device_attribute *attr, char *buf)
2826 {
2827 	struct serial_struct tmp;
2828 	struct tty_port *port = dev_get_drvdata(dev);
2829 
2830 	uart_get_info(port, &tmp);
2831 	return sprintf(buf, "%d\n", tmp.type);
2832 }
2833 
line_show(struct device * dev,struct device_attribute * attr,char * buf)2834 static ssize_t line_show(struct device *dev,
2835 	struct device_attribute *attr, char *buf)
2836 {
2837 	struct serial_struct tmp;
2838 	struct tty_port *port = dev_get_drvdata(dev);
2839 
2840 	uart_get_info(port, &tmp);
2841 	return sprintf(buf, "%d\n", tmp.line);
2842 }
2843 
port_show(struct device * dev,struct device_attribute * attr,char * buf)2844 static ssize_t port_show(struct device *dev,
2845 	struct device_attribute *attr, char *buf)
2846 {
2847 	struct serial_struct tmp;
2848 	struct tty_port *port = dev_get_drvdata(dev);
2849 	unsigned long ioaddr;
2850 
2851 	uart_get_info(port, &tmp);
2852 	ioaddr = tmp.port;
2853 	if (HIGH_BITS_OFFSET)
2854 		ioaddr |= (unsigned long)tmp.port_high << HIGH_BITS_OFFSET;
2855 	return sprintf(buf, "0x%lX\n", ioaddr);
2856 }
2857 
irq_show(struct device * dev,struct device_attribute * attr,char * buf)2858 static ssize_t irq_show(struct device *dev,
2859 	struct device_attribute *attr, char *buf)
2860 {
2861 	struct serial_struct tmp;
2862 	struct tty_port *port = dev_get_drvdata(dev);
2863 
2864 	uart_get_info(port, &tmp);
2865 	return sprintf(buf, "%d\n", tmp.irq);
2866 }
2867 
flags_show(struct device * dev,struct device_attribute * attr,char * buf)2868 static ssize_t flags_show(struct device *dev,
2869 	struct device_attribute *attr, char *buf)
2870 {
2871 	struct serial_struct tmp;
2872 	struct tty_port *port = dev_get_drvdata(dev);
2873 
2874 	uart_get_info(port, &tmp);
2875 	return sprintf(buf, "0x%X\n", tmp.flags);
2876 }
2877 
xmit_fifo_size_show(struct device * dev,struct device_attribute * attr,char * buf)2878 static ssize_t xmit_fifo_size_show(struct device *dev,
2879 	struct device_attribute *attr, char *buf)
2880 {
2881 	struct serial_struct tmp;
2882 	struct tty_port *port = dev_get_drvdata(dev);
2883 
2884 	uart_get_info(port, &tmp);
2885 	return sprintf(buf, "%d\n", tmp.xmit_fifo_size);
2886 }
2887 
close_delay_show(struct device * dev,struct device_attribute * attr,char * buf)2888 static ssize_t close_delay_show(struct device *dev,
2889 	struct device_attribute *attr, char *buf)
2890 {
2891 	struct serial_struct tmp;
2892 	struct tty_port *port = dev_get_drvdata(dev);
2893 
2894 	uart_get_info(port, &tmp);
2895 	return sprintf(buf, "%d\n", tmp.close_delay);
2896 }
2897 
closing_wait_show(struct device * dev,struct device_attribute * attr,char * buf)2898 static ssize_t closing_wait_show(struct device *dev,
2899 	struct device_attribute *attr, char *buf)
2900 {
2901 	struct serial_struct tmp;
2902 	struct tty_port *port = dev_get_drvdata(dev);
2903 
2904 	uart_get_info(port, &tmp);
2905 	return sprintf(buf, "%d\n", tmp.closing_wait);
2906 }
2907 
custom_divisor_show(struct device * dev,struct device_attribute * attr,char * buf)2908 static ssize_t custom_divisor_show(struct device *dev,
2909 	struct device_attribute *attr, char *buf)
2910 {
2911 	struct serial_struct tmp;
2912 	struct tty_port *port = dev_get_drvdata(dev);
2913 
2914 	uart_get_info(port, &tmp);
2915 	return sprintf(buf, "%d\n", tmp.custom_divisor);
2916 }
2917 
io_type_show(struct device * dev,struct device_attribute * attr,char * buf)2918 static ssize_t io_type_show(struct device *dev,
2919 	struct device_attribute *attr, char *buf)
2920 {
2921 	struct serial_struct tmp;
2922 	struct tty_port *port = dev_get_drvdata(dev);
2923 
2924 	uart_get_info(port, &tmp);
2925 	return sprintf(buf, "%d\n", tmp.io_type);
2926 }
2927 
iomem_base_show(struct device * dev,struct device_attribute * attr,char * buf)2928 static ssize_t iomem_base_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, "0x%lX\n", (unsigned long)tmp.iomem_base);
2936 }
2937 
iomem_reg_shift_show(struct device * dev,struct device_attribute * attr,char * buf)2938 static ssize_t iomem_reg_shift_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, "%d\n", tmp.iomem_reg_shift);
2946 }
2947 
console_show(struct device * dev,struct device_attribute * attr,char * buf)2948 static ssize_t console_show(struct device *dev,
2949 	struct device_attribute *attr, char *buf)
2950 {
2951 	struct tty_port *port = dev_get_drvdata(dev);
2952 	struct uart_state *state = container_of(port, struct uart_state, port);
2953 	struct uart_port *uport;
2954 	bool console = false;
2955 
2956 	mutex_lock(&port->mutex);
2957 	uport = uart_port_check(state);
2958 	if (uport)
2959 		console = uart_console_enabled(uport);
2960 	mutex_unlock(&port->mutex);
2961 
2962 	return sprintf(buf, "%c\n", console ? 'Y' : 'N');
2963 }
2964 
console_store(struct device * dev,struct device_attribute * attr,const char * buf,size_t count)2965 static ssize_t console_store(struct device *dev,
2966 	struct device_attribute *attr, const char *buf, size_t count)
2967 {
2968 	struct tty_port *port = dev_get_drvdata(dev);
2969 	struct uart_state *state = container_of(port, struct uart_state, port);
2970 	struct uart_port *uport;
2971 	bool oldconsole, newconsole;
2972 	int ret;
2973 
2974 	ret = kstrtobool(buf, &newconsole);
2975 	if (ret)
2976 		return ret;
2977 
2978 	mutex_lock(&port->mutex);
2979 	uport = uart_port_check(state);
2980 	if (uport) {
2981 		oldconsole = uart_console_enabled(uport);
2982 		if (oldconsole && !newconsole) {
2983 			ret = unregister_console(uport->cons);
2984 		} else if (!oldconsole && newconsole) {
2985 			if (uart_console(uport)) {
2986 				uport->console_reinit = 1;
2987 				register_console(uport->cons);
2988 			} else {
2989 				ret = -ENOENT;
2990 			}
2991 		}
2992 	} else {
2993 		ret = -ENXIO;
2994 	}
2995 	mutex_unlock(&port->mutex);
2996 
2997 	return ret < 0 ? ret : count;
2998 }
2999 
3000 static DEVICE_ATTR_RO(uartclk);
3001 static DEVICE_ATTR_RO(type);
3002 static DEVICE_ATTR_RO(line);
3003 static DEVICE_ATTR_RO(port);
3004 static DEVICE_ATTR_RO(irq);
3005 static DEVICE_ATTR_RO(flags);
3006 static DEVICE_ATTR_RO(xmit_fifo_size);
3007 static DEVICE_ATTR_RO(close_delay);
3008 static DEVICE_ATTR_RO(closing_wait);
3009 static DEVICE_ATTR_RO(custom_divisor);
3010 static DEVICE_ATTR_RO(io_type);
3011 static DEVICE_ATTR_RO(iomem_base);
3012 static DEVICE_ATTR_RO(iomem_reg_shift);
3013 static DEVICE_ATTR_RW(console);
3014 
3015 static struct attribute *tty_dev_attrs[] = {
3016 	&dev_attr_uartclk.attr,
3017 	&dev_attr_type.attr,
3018 	&dev_attr_line.attr,
3019 	&dev_attr_port.attr,
3020 	&dev_attr_irq.attr,
3021 	&dev_attr_flags.attr,
3022 	&dev_attr_xmit_fifo_size.attr,
3023 	&dev_attr_close_delay.attr,
3024 	&dev_attr_closing_wait.attr,
3025 	&dev_attr_custom_divisor.attr,
3026 	&dev_attr_io_type.attr,
3027 	&dev_attr_iomem_base.attr,
3028 	&dev_attr_iomem_reg_shift.attr,
3029 	&dev_attr_console.attr,
3030 	NULL
3031 };
3032 
3033 static const struct attribute_group tty_dev_attr_group = {
3034 	.attrs = tty_dev_attrs,
3035 };
3036 
3037 /**
3038  * uart_add_one_port - attach a driver-defined port structure
3039  * @drv: pointer to the uart low level driver structure for this port
3040  * @uport: uart port structure to use for this port.
3041  *
3042  * Context: task context, might sleep
3043  *
3044  * This allows the driver @drv to register its own uart_port structure with the
3045  * core driver. The main purpose is to allow the low level uart drivers to
3046  * expand uart_port, rather than having yet more levels of structures.
3047  */
uart_add_one_port(struct uart_driver * drv,struct uart_port * uport)3048 int uart_add_one_port(struct uart_driver *drv, struct uart_port *uport)
3049 {
3050 	struct uart_state *state;
3051 	struct tty_port *port;
3052 	int ret = 0;
3053 	struct device *tty_dev;
3054 	int num_groups;
3055 
3056 	if (uport->line >= drv->nr)
3057 		return -EINVAL;
3058 
3059 	state = drv->state + uport->line;
3060 	port = &state->port;
3061 
3062 	mutex_lock(&port_mutex);
3063 	mutex_lock(&port->mutex);
3064 	if (state->uart_port) {
3065 		ret = -EINVAL;
3066 		goto out;
3067 	}
3068 
3069 	/* Link the port to the driver state table and vice versa */
3070 	atomic_set(&state->refcount, 1);
3071 	init_waitqueue_head(&state->remove_wait);
3072 	state->uart_port = uport;
3073 	uport->state = state;
3074 
3075 	state->pm_state = UART_PM_STATE_UNDEFINED;
3076 	uport->cons = drv->cons;
3077 	uport->minor = drv->tty_driver->minor_start + uport->line;
3078 	uport->name = kasprintf(GFP_KERNEL, "%s%d", drv->dev_name,
3079 				drv->tty_driver->name_base + uport->line);
3080 	if (!uport->name) {
3081 		ret = -ENOMEM;
3082 		goto out;
3083 	}
3084 
3085 	/*
3086 	 * If this port is in use as a console then the spinlock is already
3087 	 * initialised.
3088 	 */
3089 	if (!uart_console_enabled(uport))
3090 		uart_port_spin_lock_init(uport);
3091 
3092 	if (uport->cons && uport->dev)
3093 		of_console_check(uport->dev->of_node, uport->cons->name, uport->line);
3094 
3095 	tty_port_link_device(port, drv->tty_driver, uport->line);
3096 	uart_configure_port(drv, state, uport);
3097 
3098 	port->console = uart_console(uport);
3099 
3100 	num_groups = 2;
3101 	if (uport->attr_group)
3102 		num_groups++;
3103 
3104 	uport->tty_groups = kcalloc(num_groups, sizeof(*uport->tty_groups),
3105 				    GFP_KERNEL);
3106 	if (!uport->tty_groups) {
3107 		ret = -ENOMEM;
3108 		goto out;
3109 	}
3110 	uport->tty_groups[0] = &tty_dev_attr_group;
3111 	if (uport->attr_group)
3112 		uport->tty_groups[1] = uport->attr_group;
3113 
3114 	/*
3115 	 * Register the port whether it's detected or not.  This allows
3116 	 * setserial to be used to alter this port's parameters.
3117 	 */
3118 	tty_dev = tty_port_register_device_attr_serdev(port, drv->tty_driver,
3119 			uport->line, uport->dev, port, uport->tty_groups);
3120 	if (!IS_ERR(tty_dev)) {
3121 		device_set_wakeup_capable(tty_dev, 1);
3122 	} else {
3123 		dev_err(uport->dev, "Cannot register tty device on line %d\n",
3124 		       uport->line);
3125 	}
3126 
3127 	/*
3128 	 * Ensure UPF_DEAD is not set.
3129 	 */
3130 	uport->flags &= ~UPF_DEAD;
3131 
3132  out:
3133 	mutex_unlock(&port->mutex);
3134 	mutex_unlock(&port_mutex);
3135 
3136 	return ret;
3137 }
3138 EXPORT_SYMBOL(uart_add_one_port);
3139 
3140 /**
3141  * uart_remove_one_port - detach a driver defined port structure
3142  * @drv: pointer to the uart low level driver structure for this port
3143  * @uport: uart port structure for this port
3144  *
3145  * Context: task context, might sleep
3146  *
3147  * This unhooks (and hangs up) the specified port structure from the core
3148  * driver. No further calls will be made to the low-level code for this port.
3149  */
uart_remove_one_port(struct uart_driver * drv,struct uart_port * uport)3150 int uart_remove_one_port(struct uart_driver *drv, struct uart_port *uport)
3151 {
3152 	struct uart_state *state = drv->state + uport->line;
3153 	struct tty_port *port = &state->port;
3154 	struct uart_port *uart_port;
3155 	struct tty_struct *tty;
3156 	int ret = 0;
3157 
3158 	mutex_lock(&port_mutex);
3159 
3160 	/*
3161 	 * Mark the port "dead" - this prevents any opens from
3162 	 * succeeding while we shut down the port.
3163 	 */
3164 	mutex_lock(&port->mutex);
3165 	uart_port = uart_port_check(state);
3166 	if (uart_port != uport)
3167 		dev_alert(uport->dev, "Removing wrong port: %p != %p\n",
3168 			  uart_port, uport);
3169 
3170 	if (!uart_port) {
3171 		mutex_unlock(&port->mutex);
3172 		ret = -EINVAL;
3173 		goto out;
3174 	}
3175 	uport->flags |= UPF_DEAD;
3176 	mutex_unlock(&port->mutex);
3177 
3178 	/*
3179 	 * Remove the devices from the tty layer
3180 	 */
3181 	tty_port_unregister_device(port, drv->tty_driver, uport->line);
3182 
3183 	tty = tty_port_tty_get(port);
3184 	if (tty) {
3185 		tty_vhangup(port->tty);
3186 		tty_kref_put(tty);
3187 	}
3188 
3189 	/*
3190 	 * If the port is used as a console, unregister it
3191 	 */
3192 	if (uart_console(uport))
3193 		unregister_console(uport->cons);
3194 
3195 	/*
3196 	 * Free the port IO and memory resources, if any.
3197 	 */
3198 	if (uport->type != PORT_UNKNOWN && uport->ops->release_port)
3199 		uport->ops->release_port(uport);
3200 	kfree(uport->tty_groups);
3201 	kfree(uport->name);
3202 
3203 	/*
3204 	 * Indicate that there isn't a port here anymore.
3205 	 */
3206 	uport->type = PORT_UNKNOWN;
3207 
3208 	mutex_lock(&port->mutex);
3209 	WARN_ON(atomic_dec_return(&state->refcount) < 0);
3210 	wait_event(state->remove_wait, !atomic_read(&state->refcount));
3211 	state->uart_port = NULL;
3212 	mutex_unlock(&port->mutex);
3213 out:
3214 	mutex_unlock(&port_mutex);
3215 
3216 	return ret;
3217 }
3218 EXPORT_SYMBOL(uart_remove_one_port);
3219 
3220 /**
3221  * uart_match_port - are the two ports equivalent?
3222  * @port1: first port
3223  * @port2: second port
3224  *
3225  * This utility function can be used to determine whether two uart_port
3226  * structures describe the same port.
3227  */
uart_match_port(const struct uart_port * port1,const struct uart_port * port2)3228 bool uart_match_port(const struct uart_port *port1,
3229 		const struct uart_port *port2)
3230 {
3231 	if (port1->iotype != port2->iotype)
3232 		return false;
3233 
3234 	switch (port1->iotype) {
3235 	case UPIO_PORT:
3236 		return port1->iobase == port2->iobase;
3237 	case UPIO_HUB6:
3238 		return port1->iobase == port2->iobase &&
3239 		       port1->hub6   == port2->hub6;
3240 	case UPIO_MEM:
3241 	case UPIO_MEM16:
3242 	case UPIO_MEM32:
3243 	case UPIO_MEM32BE:
3244 	case UPIO_AU:
3245 	case UPIO_TSI:
3246 		return port1->mapbase == port2->mapbase;
3247 	}
3248 
3249 	return false;
3250 }
3251 EXPORT_SYMBOL(uart_match_port);
3252 
3253 /**
3254  * uart_handle_dcd_change - handle a change of carrier detect state
3255  * @uport: uart_port structure for the open port
3256  * @status: new carrier detect status, nonzero if active
3257  *
3258  * Caller must hold uport->lock.
3259  */
uart_handle_dcd_change(struct uart_port * uport,unsigned int status)3260 void uart_handle_dcd_change(struct uart_port *uport, unsigned int status)
3261 {
3262 	struct tty_port *port = &uport->state->port;
3263 	struct tty_struct *tty = port->tty;
3264 	struct tty_ldisc *ld;
3265 
3266 	lockdep_assert_held_once(&uport->lock);
3267 
3268 	if (tty) {
3269 		ld = tty_ldisc_ref(tty);
3270 		if (ld) {
3271 			if (ld->ops->dcd_change)
3272 				ld->ops->dcd_change(tty, status);
3273 			tty_ldisc_deref(ld);
3274 		}
3275 	}
3276 
3277 	uport->icount.dcd++;
3278 
3279 	if (uart_dcd_enabled(uport)) {
3280 		if (status)
3281 			wake_up_interruptible(&port->open_wait);
3282 		else if (tty)
3283 			tty_hangup(tty);
3284 	}
3285 }
3286 EXPORT_SYMBOL_GPL(uart_handle_dcd_change);
3287 
3288 /**
3289  * uart_handle_cts_change - handle a change of clear-to-send state
3290  * @uport: uart_port structure for the open port
3291  * @status: new clear to send status, nonzero if active
3292  *
3293  * Caller must hold uport->lock.
3294  */
uart_handle_cts_change(struct uart_port * uport,unsigned int status)3295 void uart_handle_cts_change(struct uart_port *uport, unsigned int status)
3296 {
3297 	lockdep_assert_held_once(&uport->lock);
3298 
3299 	uport->icount.cts++;
3300 
3301 	if (uart_softcts_mode(uport)) {
3302 		if (uport->hw_stopped) {
3303 			if (status) {
3304 				uport->hw_stopped = 0;
3305 				uport->ops->start_tx(uport);
3306 				uart_write_wakeup(uport);
3307 			}
3308 		} else {
3309 			if (!status) {
3310 				uport->hw_stopped = 1;
3311 				uport->ops->stop_tx(uport);
3312 			}
3313 		}
3314 
3315 	}
3316 }
3317 EXPORT_SYMBOL_GPL(uart_handle_cts_change);
3318 
3319 /**
3320  * uart_insert_char - push a char to the uart layer
3321  *
3322  * User is responsible to call tty_flip_buffer_push when they are done with
3323  * insertion.
3324  *
3325  * @port: corresponding port
3326  * @status: state of the serial port RX buffer (LSR for 8250)
3327  * @overrun: mask of overrun bits in @status
3328  * @ch: character to push
3329  * @flag: flag for the character (see TTY_NORMAL and friends)
3330  */
uart_insert_char(struct uart_port * port,unsigned int status,unsigned int overrun,unsigned int ch,unsigned int flag)3331 void uart_insert_char(struct uart_port *port, unsigned int status,
3332 		 unsigned int overrun, unsigned int ch, unsigned int flag)
3333 {
3334 	struct tty_port *tport = &port->state->port;
3335 
3336 	if ((status & port->ignore_status_mask & ~overrun) == 0)
3337 		if (tty_insert_flip_char(tport, ch, flag) == 0)
3338 			++port->icount.buf_overrun;
3339 
3340 	/*
3341 	 * Overrun is special.  Since it's reported immediately,
3342 	 * it doesn't affect the current character.
3343 	 */
3344 	if (status & ~port->ignore_status_mask & overrun)
3345 		if (tty_insert_flip_char(tport, 0, TTY_OVERRUN) == 0)
3346 			++port->icount.buf_overrun;
3347 }
3348 EXPORT_SYMBOL_GPL(uart_insert_char);
3349 
3350 #ifdef CONFIG_MAGIC_SYSRQ_SERIAL
3351 static const char sysrq_toggle_seq[] = CONFIG_MAGIC_SYSRQ_SERIAL_SEQUENCE;
3352 
uart_sysrq_on(struct work_struct * w)3353 static void uart_sysrq_on(struct work_struct *w)
3354 {
3355 	int sysrq_toggle_seq_len = strlen(sysrq_toggle_seq);
3356 
3357 	sysrq_toggle_support(1);
3358 	pr_info("SysRq is enabled by magic sequence '%*pE' on serial\n",
3359 		sysrq_toggle_seq_len, sysrq_toggle_seq);
3360 }
3361 static DECLARE_WORK(sysrq_enable_work, uart_sysrq_on);
3362 
3363 /**
3364  * uart_try_toggle_sysrq - Enables SysRq from serial line
3365  * @port: uart_port structure where char(s) after BREAK met
3366  * @ch: new character in the sequence after received BREAK
3367  *
3368  * Enables magic SysRq when the required sequence is met on port
3369  * (see CONFIG_MAGIC_SYSRQ_SERIAL_SEQUENCE).
3370  *
3371  * Returns: %false if @ch is out of enabling sequence and should be
3372  * handled some other way, %true if @ch was consumed.
3373  */
uart_try_toggle_sysrq(struct uart_port * port,unsigned int ch)3374 bool uart_try_toggle_sysrq(struct uart_port *port, unsigned int ch)
3375 {
3376 	int sysrq_toggle_seq_len = strlen(sysrq_toggle_seq);
3377 
3378 	if (!sysrq_toggle_seq_len)
3379 		return false;
3380 
3381 	BUILD_BUG_ON(ARRAY_SIZE(sysrq_toggle_seq) >= U8_MAX);
3382 	if (sysrq_toggle_seq[port->sysrq_seq] != ch) {
3383 		port->sysrq_seq = 0;
3384 		return false;
3385 	}
3386 
3387 	if (++port->sysrq_seq < sysrq_toggle_seq_len) {
3388 		port->sysrq = jiffies + SYSRQ_TIMEOUT;
3389 		return true;
3390 	}
3391 
3392 	schedule_work(&sysrq_enable_work);
3393 
3394 	port->sysrq = 0;
3395 	return true;
3396 }
3397 EXPORT_SYMBOL_GPL(uart_try_toggle_sysrq);
3398 #endif
3399 
3400 /**
3401  * uart_get_rs485_mode() - retrieve rs485 properties for given uart
3402  * @port: uart device's target port
3403  *
3404  * This function implements the device tree binding described in
3405  * Documentation/devicetree/bindings/serial/rs485.txt.
3406  */
uart_get_rs485_mode(struct uart_port * port)3407 int uart_get_rs485_mode(struct uart_port *port)
3408 {
3409 	struct serial_rs485 *rs485conf = &port->rs485;
3410 	struct device *dev = port->dev;
3411 	u32 rs485_delay[2];
3412 	int ret;
3413 
3414 	ret = device_property_read_u32_array(dev, "rs485-rts-delay",
3415 					     rs485_delay, 2);
3416 	if (!ret) {
3417 		rs485conf->delay_rts_before_send = rs485_delay[0];
3418 		rs485conf->delay_rts_after_send = rs485_delay[1];
3419 	} else {
3420 		rs485conf->delay_rts_before_send = 0;
3421 		rs485conf->delay_rts_after_send = 0;
3422 	}
3423 
3424 	uart_sanitize_serial_rs485_delays(port, rs485conf);
3425 
3426 	/*
3427 	 * Clear full-duplex and enabled flags, set RTS polarity to active high
3428 	 * to get to a defined state with the following properties:
3429 	 */
3430 	rs485conf->flags &= ~(SER_RS485_RX_DURING_TX | SER_RS485_ENABLED |
3431 			      SER_RS485_TERMINATE_BUS |
3432 			      SER_RS485_RTS_AFTER_SEND);
3433 	rs485conf->flags |= SER_RS485_RTS_ON_SEND;
3434 
3435 	if (device_property_read_bool(dev, "rs485-rx-during-tx"))
3436 		rs485conf->flags |= SER_RS485_RX_DURING_TX;
3437 
3438 	if (device_property_read_bool(dev, "linux,rs485-enabled-at-boot-time"))
3439 		rs485conf->flags |= SER_RS485_ENABLED;
3440 
3441 	if (device_property_read_bool(dev, "rs485-rts-active-low")) {
3442 		rs485conf->flags &= ~SER_RS485_RTS_ON_SEND;
3443 		rs485conf->flags |= SER_RS485_RTS_AFTER_SEND;
3444 	}
3445 
3446 	/*
3447 	 * Disabling termination by default is the safe choice:  Else if many
3448 	 * bus participants enable it, no communication is possible at all.
3449 	 * Works fine for short cables and users may enable for longer cables.
3450 	 */
3451 	port->rs485_term_gpio = devm_gpiod_get_optional(dev, "rs485-term",
3452 							GPIOD_OUT_LOW);
3453 	if (IS_ERR(port->rs485_term_gpio)) {
3454 		ret = PTR_ERR(port->rs485_term_gpio);
3455 		port->rs485_term_gpio = NULL;
3456 		return dev_err_probe(dev, ret, "Cannot get rs485-term-gpios\n");
3457 	}
3458 	if (port->rs485_term_gpio)
3459 		port->rs485_supported.flags |= SER_RS485_TERMINATE_BUS;
3460 
3461 	return 0;
3462 }
3463 EXPORT_SYMBOL_GPL(uart_get_rs485_mode);
3464 
3465 /* Compile-time assertions for serial_rs485 layout */
3466 static_assert(offsetof(struct serial_rs485, padding) ==
3467               (offsetof(struct serial_rs485, delay_rts_after_send) + sizeof(__u32)));
3468 static_assert(offsetof(struct serial_rs485, padding1) ==
3469 	      offsetof(struct serial_rs485, padding[1]));
3470 static_assert((offsetof(struct serial_rs485, padding[4]) + sizeof(__u32)) ==
3471 	      sizeof(struct serial_rs485));
3472 
3473 MODULE_DESCRIPTION("Serial driver core");
3474 MODULE_LICENSE("GPL");
3475