xref: /openbmc/linux/drivers/tty/serial/serial_core.c (revision e7253313)
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/of.h>
18 #include <linux/proc_fs.h>
19 #include <linux/seq_file.h>
20 #include <linux/device.h>
21 #include <linux/serial.h> /* for serial_state and serial_icounter_struct */
22 #include <linux/serial_core.h>
23 #include <linux/delay.h>
24 #include <linux/mutex.h>
25 #include <linux/security.h>
26 
27 #include <linux/irq.h>
28 #include <linux/uaccess.h>
29 
30 /*
31  * This is used to lock changes in serial line configuration.
32  */
33 static DEFINE_MUTEX(port_mutex);
34 
35 /*
36  * lockdep: port->lock is initialized in two places, but we
37  *          want only one lock-class:
38  */
39 static struct lock_class_key port_lock_key;
40 
41 #define HIGH_BITS_OFFSET	((sizeof(long)-sizeof(int))*8)
42 
43 static void uart_change_speed(struct tty_struct *tty, struct uart_state *state,
44 					struct ktermios *old_termios);
45 static void uart_wait_until_sent(struct tty_struct *tty, int timeout);
46 static void uart_change_pm(struct uart_state *state,
47 			   enum uart_pm_state pm_state);
48 
49 static void uart_port_shutdown(struct tty_port *port);
50 
51 static int uart_dcd_enabled(struct uart_port *uport)
52 {
53 	return !!(uport->status & UPSTAT_DCD_ENABLE);
54 }
55 
56 static inline struct uart_port *uart_port_ref(struct uart_state *state)
57 {
58 	if (atomic_add_unless(&state->refcount, 1, 0))
59 		return state->uart_port;
60 	return NULL;
61 }
62 
63 static inline void uart_port_deref(struct uart_port *uport)
64 {
65 	if (atomic_dec_and_test(&uport->state->refcount))
66 		wake_up(&uport->state->remove_wait);
67 }
68 
69 #define uart_port_lock(state, flags)					\
70 	({								\
71 		struct uart_port *__uport = uart_port_ref(state);	\
72 		if (__uport)						\
73 			spin_lock_irqsave(&__uport->lock, flags);	\
74 		__uport;						\
75 	})
76 
77 #define uart_port_unlock(uport, flags)					\
78 	({								\
79 		struct uart_port *__uport = uport;			\
80 		if (__uport) {						\
81 			spin_unlock_irqrestore(&__uport->lock, flags);	\
82 			uart_port_deref(__uport);			\
83 		}							\
84 	})
85 
86 static inline struct uart_port *uart_port_check(struct uart_state *state)
87 {
88 	lockdep_assert_held(&state->port.mutex);
89 	return state->uart_port;
90 }
91 
92 /*
93  * This routine is used by the interrupt handler to schedule processing in
94  * the software interrupt portion of the driver.
95  */
96 void uart_write_wakeup(struct uart_port *port)
97 {
98 	struct uart_state *state = port->state;
99 	/*
100 	 * This means you called this function _after_ the port was
101 	 * closed.  No cookie for you.
102 	 */
103 	BUG_ON(!state);
104 	tty_port_tty_wakeup(&state->port);
105 }
106 
107 static void uart_stop(struct tty_struct *tty)
108 {
109 	struct uart_state *state = tty->driver_data;
110 	struct uart_port *port;
111 	unsigned long flags;
112 
113 	port = uart_port_lock(state, flags);
114 	if (port)
115 		port->ops->stop_tx(port);
116 	uart_port_unlock(port, flags);
117 }
118 
119 static void __uart_start(struct tty_struct *tty)
120 {
121 	struct uart_state *state = tty->driver_data;
122 	struct uart_port *port = state->uart_port;
123 
124 	if (port && !uart_tx_stopped(port))
125 		port->ops->start_tx(port);
126 }
127 
128 static void uart_start(struct tty_struct *tty)
129 {
130 	struct uart_state *state = tty->driver_data;
131 	struct uart_port *port;
132 	unsigned long flags;
133 
134 	port = uart_port_lock(state, flags);
135 	__uart_start(tty);
136 	uart_port_unlock(port, flags);
137 }
138 
139 static void
140 uart_update_mctrl(struct uart_port *port, unsigned int set, unsigned int clear)
141 {
142 	unsigned long flags;
143 	unsigned int old;
144 
145 	spin_lock_irqsave(&port->lock, flags);
146 	old = port->mctrl;
147 	port->mctrl = (old & ~clear) | set;
148 	if (old != port->mctrl)
149 		port->ops->set_mctrl(port, port->mctrl);
150 	spin_unlock_irqrestore(&port->lock, flags);
151 }
152 
153 #define uart_set_mctrl(port, set)	uart_update_mctrl(port, set, 0)
154 #define uart_clear_mctrl(port, clear)	uart_update_mctrl(port, 0, clear)
155 
156 static void uart_port_dtr_rts(struct uart_port *uport, int raise)
157 {
158 	int rs485_on = uport->rs485_config &&
159 		(uport->rs485.flags & SER_RS485_ENABLED);
160 	int RTS_after_send = !!(uport->rs485.flags & SER_RS485_RTS_AFTER_SEND);
161 
162 	if (raise) {
163 		if (rs485_on && !RTS_after_send) {
164 			uart_set_mctrl(uport, TIOCM_DTR);
165 			uart_clear_mctrl(uport, TIOCM_RTS);
166 		} else {
167 			uart_set_mctrl(uport, TIOCM_DTR | TIOCM_RTS);
168 		}
169 	} else {
170 		unsigned int clear = TIOCM_DTR;
171 
172 		clear |= (!rs485_on || !RTS_after_send) ? TIOCM_RTS : 0;
173 		uart_clear_mctrl(uport, clear);
174 	}
175 }
176 
177 /*
178  * Startup the port.  This will be called once per open.  All calls
179  * will be serialised by the per-port mutex.
180  */
181 static int uart_port_startup(struct tty_struct *tty, struct uart_state *state,
182 		int init_hw)
183 {
184 	struct uart_port *uport = uart_port_check(state);
185 	unsigned long page;
186 	unsigned long flags = 0;
187 	int retval = 0;
188 
189 	if (uport->type == PORT_UNKNOWN)
190 		return 1;
191 
192 	/*
193 	 * Make sure the device is in D0 state.
194 	 */
195 	uart_change_pm(state, UART_PM_STATE_ON);
196 
197 	/*
198 	 * Initialise and allocate the transmit and temporary
199 	 * buffer.
200 	 */
201 	page = get_zeroed_page(GFP_KERNEL);
202 	if (!page)
203 		return -ENOMEM;
204 
205 	uart_port_lock(state, flags);
206 	if (!state->xmit.buf) {
207 		state->xmit.buf = (unsigned char *) page;
208 		uart_circ_clear(&state->xmit);
209 		uart_port_unlock(uport, flags);
210 	} else {
211 		uart_port_unlock(uport, flags);
212 		/*
213 		 * Do not free() the page under the port lock, see
214 		 * uart_shutdown().
215 		 */
216 		free_page(page);
217 	}
218 
219 	retval = uport->ops->startup(uport);
220 	if (retval == 0) {
221 		if (uart_console(uport) && uport->cons->cflag) {
222 			tty->termios.c_cflag = uport->cons->cflag;
223 			uport->cons->cflag = 0;
224 		}
225 		/*
226 		 * Initialise the hardware port settings.
227 		 */
228 		uart_change_speed(tty, state, NULL);
229 
230 		/*
231 		 * Setup the RTS and DTR signals once the
232 		 * port is open and ready to respond.
233 		 */
234 		if (init_hw && C_BAUD(tty))
235 			uart_port_dtr_rts(uport, 1);
236 	}
237 
238 	/*
239 	 * This is to allow setserial on this port. People may want to set
240 	 * port/irq/type and then reconfigure the port properly if it failed
241 	 * now.
242 	 */
243 	if (retval && capable(CAP_SYS_ADMIN))
244 		return 1;
245 
246 	return retval;
247 }
248 
249 static int uart_startup(struct tty_struct *tty, struct uart_state *state,
250 		int init_hw)
251 {
252 	struct tty_port *port = &state->port;
253 	int retval;
254 
255 	if (tty_port_initialized(port))
256 		return 0;
257 
258 	retval = uart_port_startup(tty, state, init_hw);
259 	if (retval)
260 		set_bit(TTY_IO_ERROR, &tty->flags);
261 
262 	return retval;
263 }
264 
265 /*
266  * This routine will shutdown a serial port; interrupts are disabled, and
267  * DTR is dropped if the hangup on close termio flag is on.  Calls to
268  * uart_shutdown are serialised by the per-port semaphore.
269  *
270  * uport == NULL if uart_port has already been removed
271  */
272 static void uart_shutdown(struct tty_struct *tty, struct uart_state *state)
273 {
274 	struct uart_port *uport = uart_port_check(state);
275 	struct tty_port *port = &state->port;
276 	unsigned long flags = 0;
277 	char *xmit_buf = NULL;
278 
279 	/*
280 	 * Set the TTY IO error marker
281 	 */
282 	if (tty)
283 		set_bit(TTY_IO_ERROR, &tty->flags);
284 
285 	if (tty_port_initialized(port)) {
286 		tty_port_set_initialized(port, 0);
287 
288 		/*
289 		 * Turn off DTR and RTS early.
290 		 */
291 		if (uport && uart_console(uport) && tty)
292 			uport->cons->cflag = tty->termios.c_cflag;
293 
294 		if (!tty || C_HUPCL(tty))
295 			uart_port_dtr_rts(uport, 0);
296 
297 		uart_port_shutdown(port);
298 	}
299 
300 	/*
301 	 * It's possible for shutdown to be called after suspend if we get
302 	 * a DCD drop (hangup) at just the right time.  Clear suspended bit so
303 	 * we don't try to resume a port that has been shutdown.
304 	 */
305 	tty_port_set_suspended(port, 0);
306 
307 	/*
308 	 * Do not free() the transmit buffer page under the port lock since
309 	 * this can create various circular locking scenarios. For instance,
310 	 * console driver may need to allocate/free a debug object, which
311 	 * can endup in printk() recursion.
312 	 */
313 	uart_port_lock(state, flags);
314 	xmit_buf = state->xmit.buf;
315 	state->xmit.buf = NULL;
316 	uart_port_unlock(uport, flags);
317 
318 	if (xmit_buf)
319 		free_page((unsigned long)xmit_buf);
320 }
321 
322 /**
323  *	uart_update_timeout - update per-port FIFO timeout.
324  *	@port:  uart_port structure describing the port
325  *	@cflag: termios cflag value
326  *	@baud:  speed of the port
327  *
328  *	Set the port FIFO timeout value.  The @cflag value should
329  *	reflect the actual hardware settings.
330  */
331 void
332 uart_update_timeout(struct uart_port *port, unsigned int cflag,
333 		    unsigned int baud)
334 {
335 	unsigned int bits;
336 
337 	/* byte size and parity */
338 	switch (cflag & CSIZE) {
339 	case CS5:
340 		bits = 7;
341 		break;
342 	case CS6:
343 		bits = 8;
344 		break;
345 	case CS7:
346 		bits = 9;
347 		break;
348 	default:
349 		bits = 10;
350 		break; /* CS8 */
351 	}
352 
353 	if (cflag & CSTOPB)
354 		bits++;
355 	if (cflag & PARENB)
356 		bits++;
357 
358 	/*
359 	 * The total number of bits to be transmitted in the fifo.
360 	 */
361 	bits = bits * port->fifosize;
362 
363 	/*
364 	 * Figure the timeout to send the above number of bits.
365 	 * Add .02 seconds of slop
366 	 */
367 	port->timeout = (HZ * bits) / baud + HZ/50;
368 }
369 
370 EXPORT_SYMBOL(uart_update_timeout);
371 
372 /**
373  *	uart_get_baud_rate - return baud rate for a particular port
374  *	@port: uart_port structure describing the port in question.
375  *	@termios: desired termios settings.
376  *	@old: old termios (or NULL)
377  *	@min: minimum acceptable baud rate
378  *	@max: maximum acceptable baud rate
379  *
380  *	Decode the termios structure into a numeric baud rate,
381  *	taking account of the magic 38400 baud rate (with spd_*
382  *	flags), and mapping the %B0 rate to 9600 baud.
383  *
384  *	If the new baud rate is invalid, try the old termios setting.
385  *	If it's still invalid, we try 9600 baud.
386  *
387  *	Update the @termios structure to reflect the baud rate
388  *	we're actually going to be using. Don't do this for the case
389  *	where B0 is requested ("hang up").
390  */
391 unsigned int
392 uart_get_baud_rate(struct uart_port *port, struct ktermios *termios,
393 		   struct ktermios *old, unsigned int min, unsigned int max)
394 {
395 	unsigned int try;
396 	unsigned int baud;
397 	unsigned int altbaud;
398 	int hung_up = 0;
399 	upf_t flags = port->flags & UPF_SPD_MASK;
400 
401 	switch (flags) {
402 	case UPF_SPD_HI:
403 		altbaud = 57600;
404 		break;
405 	case UPF_SPD_VHI:
406 		altbaud = 115200;
407 		break;
408 	case UPF_SPD_SHI:
409 		altbaud = 230400;
410 		break;
411 	case UPF_SPD_WARP:
412 		altbaud = 460800;
413 		break;
414 	default:
415 		altbaud = 38400;
416 		break;
417 	}
418 
419 	for (try = 0; try < 2; try++) {
420 		baud = tty_termios_baud_rate(termios);
421 
422 		/*
423 		 * The spd_hi, spd_vhi, spd_shi, spd_warp kludge...
424 		 * Die! Die! Die!
425 		 */
426 		if (try == 0 && baud == 38400)
427 			baud = altbaud;
428 
429 		/*
430 		 * Special case: B0 rate.
431 		 */
432 		if (baud == 0) {
433 			hung_up = 1;
434 			baud = 9600;
435 		}
436 
437 		if (baud >= min && baud <= max)
438 			return baud;
439 
440 		/*
441 		 * Oops, the quotient was zero.  Try again with
442 		 * the old baud rate if possible.
443 		 */
444 		termios->c_cflag &= ~CBAUD;
445 		if (old) {
446 			baud = tty_termios_baud_rate(old);
447 			if (!hung_up)
448 				tty_termios_encode_baud_rate(termios,
449 								baud, baud);
450 			old = NULL;
451 			continue;
452 		}
453 
454 		/*
455 		 * As a last resort, if the range cannot be met then clip to
456 		 * the nearest chip supported rate.
457 		 */
458 		if (!hung_up) {
459 			if (baud <= min)
460 				tty_termios_encode_baud_rate(termios,
461 							min + 1, min + 1);
462 			else
463 				tty_termios_encode_baud_rate(termios,
464 							max - 1, max - 1);
465 		}
466 	}
467 	/* Should never happen */
468 	WARN_ON(1);
469 	return 0;
470 }
471 
472 EXPORT_SYMBOL(uart_get_baud_rate);
473 
474 /**
475  *	uart_get_divisor - return uart clock divisor
476  *	@port: uart_port structure describing the port.
477  *	@baud: desired baud rate
478  *
479  *	Calculate the uart clock divisor for the port.
480  */
481 unsigned int
482 uart_get_divisor(struct uart_port *port, unsigned int baud)
483 {
484 	unsigned int quot;
485 
486 	/*
487 	 * Old custom speed handling.
488 	 */
489 	if (baud == 38400 && (port->flags & UPF_SPD_MASK) == UPF_SPD_CUST)
490 		quot = port->custom_divisor;
491 	else
492 		quot = DIV_ROUND_CLOSEST(port->uartclk, 16 * baud);
493 
494 	return quot;
495 }
496 
497 EXPORT_SYMBOL(uart_get_divisor);
498 
499 /* Caller holds port mutex */
500 static void uart_change_speed(struct tty_struct *tty, struct uart_state *state,
501 					struct ktermios *old_termios)
502 {
503 	struct uart_port *uport = uart_port_check(state);
504 	struct ktermios *termios;
505 	int hw_stopped;
506 
507 	/*
508 	 * If we have no tty, termios, or the port does not exist,
509 	 * then we can't set the parameters for this port.
510 	 */
511 	if (!tty || uport->type == PORT_UNKNOWN)
512 		return;
513 
514 	termios = &tty->termios;
515 	uport->ops->set_termios(uport, termios, old_termios);
516 
517 	/*
518 	 * Set modem status enables based on termios cflag
519 	 */
520 	spin_lock_irq(&uport->lock);
521 	if (termios->c_cflag & CRTSCTS)
522 		uport->status |= UPSTAT_CTS_ENABLE;
523 	else
524 		uport->status &= ~UPSTAT_CTS_ENABLE;
525 
526 	if (termios->c_cflag & CLOCAL)
527 		uport->status &= ~UPSTAT_DCD_ENABLE;
528 	else
529 		uport->status |= UPSTAT_DCD_ENABLE;
530 
531 	/* reset sw-assisted CTS flow control based on (possibly) new mode */
532 	hw_stopped = uport->hw_stopped;
533 	uport->hw_stopped = uart_softcts_mode(uport) &&
534 				!(uport->ops->get_mctrl(uport) & TIOCM_CTS);
535 	if (uport->hw_stopped) {
536 		if (!hw_stopped)
537 			uport->ops->stop_tx(uport);
538 	} else {
539 		if (hw_stopped)
540 			__uart_start(tty);
541 	}
542 	spin_unlock_irq(&uport->lock);
543 }
544 
545 static int uart_put_char(struct tty_struct *tty, unsigned char c)
546 {
547 	struct uart_state *state = tty->driver_data;
548 	struct uart_port *port;
549 	struct circ_buf *circ;
550 	unsigned long flags;
551 	int ret = 0;
552 
553 	circ = &state->xmit;
554 	port = uart_port_lock(state, flags);
555 	if (!circ->buf) {
556 		uart_port_unlock(port, flags);
557 		return 0;
558 	}
559 
560 	if (port && uart_circ_chars_free(circ) != 0) {
561 		circ->buf[circ->head] = c;
562 		circ->head = (circ->head + 1) & (UART_XMIT_SIZE - 1);
563 		ret = 1;
564 	}
565 	uart_port_unlock(port, flags);
566 	return ret;
567 }
568 
569 static void uart_flush_chars(struct tty_struct *tty)
570 {
571 	uart_start(tty);
572 }
573 
574 static int uart_write(struct tty_struct *tty,
575 					const unsigned char *buf, int count)
576 {
577 	struct uart_state *state = tty->driver_data;
578 	struct uart_port *port;
579 	struct circ_buf *circ;
580 	unsigned long flags;
581 	int c, ret = 0;
582 
583 	/*
584 	 * This means you called this function _after_ the port was
585 	 * closed.  No cookie for you.
586 	 */
587 	if (!state) {
588 		WARN_ON(1);
589 		return -EL3HLT;
590 	}
591 
592 	port = uart_port_lock(state, flags);
593 	circ = &state->xmit;
594 	if (!circ->buf) {
595 		uart_port_unlock(port, flags);
596 		return 0;
597 	}
598 
599 	while (port) {
600 		c = CIRC_SPACE_TO_END(circ->head, circ->tail, UART_XMIT_SIZE);
601 		if (count < c)
602 			c = count;
603 		if (c <= 0)
604 			break;
605 		memcpy(circ->buf + circ->head, buf, c);
606 		circ->head = (circ->head + c) & (UART_XMIT_SIZE - 1);
607 		buf += c;
608 		count -= c;
609 		ret += c;
610 	}
611 
612 	__uart_start(tty);
613 	uart_port_unlock(port, flags);
614 	return ret;
615 }
616 
617 static int uart_write_room(struct tty_struct *tty)
618 {
619 	struct uart_state *state = tty->driver_data;
620 	struct uart_port *port;
621 	unsigned long flags;
622 	int ret;
623 
624 	port = uart_port_lock(state, flags);
625 	ret = uart_circ_chars_free(&state->xmit);
626 	uart_port_unlock(port, flags);
627 	return ret;
628 }
629 
630 static int uart_chars_in_buffer(struct tty_struct *tty)
631 {
632 	struct uart_state *state = tty->driver_data;
633 	struct uart_port *port;
634 	unsigned long flags;
635 	int ret;
636 
637 	port = uart_port_lock(state, flags);
638 	ret = uart_circ_chars_pending(&state->xmit);
639 	uart_port_unlock(port, flags);
640 	return ret;
641 }
642 
643 static void uart_flush_buffer(struct tty_struct *tty)
644 {
645 	struct uart_state *state = tty->driver_data;
646 	struct uart_port *port;
647 	unsigned long flags;
648 
649 	/*
650 	 * This means you called this function _after_ the port was
651 	 * closed.  No cookie for you.
652 	 */
653 	if (!state) {
654 		WARN_ON(1);
655 		return;
656 	}
657 
658 	pr_debug("uart_flush_buffer(%d) called\n", tty->index);
659 
660 	port = uart_port_lock(state, flags);
661 	if (!port)
662 		return;
663 	uart_circ_clear(&state->xmit);
664 	if (port->ops->flush_buffer)
665 		port->ops->flush_buffer(port);
666 	uart_port_unlock(port, flags);
667 	tty_port_tty_wakeup(&state->port);
668 }
669 
670 /*
671  * This function is used to send a high-priority XON/XOFF character to
672  * the device
673  */
674 static void uart_send_xchar(struct tty_struct *tty, char ch)
675 {
676 	struct uart_state *state = tty->driver_data;
677 	struct uart_port *port;
678 	unsigned long flags;
679 
680 	port = uart_port_ref(state);
681 	if (!port)
682 		return;
683 
684 	if (port->ops->send_xchar)
685 		port->ops->send_xchar(port, ch);
686 	else {
687 		spin_lock_irqsave(&port->lock, flags);
688 		port->x_char = ch;
689 		if (ch)
690 			port->ops->start_tx(port);
691 		spin_unlock_irqrestore(&port->lock, flags);
692 	}
693 	uart_port_deref(port);
694 }
695 
696 static void uart_throttle(struct tty_struct *tty)
697 {
698 	struct uart_state *state = tty->driver_data;
699 	upstat_t mask = UPSTAT_SYNC_FIFO;
700 	struct uart_port *port;
701 
702 	port = uart_port_ref(state);
703 	if (!port)
704 		return;
705 
706 	if (I_IXOFF(tty))
707 		mask |= UPSTAT_AUTOXOFF;
708 	if (C_CRTSCTS(tty))
709 		mask |= UPSTAT_AUTORTS;
710 
711 	if (port->status & mask) {
712 		port->ops->throttle(port);
713 		mask &= ~port->status;
714 	}
715 
716 	if (mask & UPSTAT_AUTORTS)
717 		uart_clear_mctrl(port, TIOCM_RTS);
718 
719 	if (mask & UPSTAT_AUTOXOFF)
720 		uart_send_xchar(tty, STOP_CHAR(tty));
721 
722 	uart_port_deref(port);
723 }
724 
725 static void uart_unthrottle(struct tty_struct *tty)
726 {
727 	struct uart_state *state = tty->driver_data;
728 	upstat_t mask = UPSTAT_SYNC_FIFO;
729 	struct uart_port *port;
730 
731 	port = uart_port_ref(state);
732 	if (!port)
733 		return;
734 
735 	if (I_IXOFF(tty))
736 		mask |= UPSTAT_AUTOXOFF;
737 	if (C_CRTSCTS(tty))
738 		mask |= UPSTAT_AUTORTS;
739 
740 	if (port->status & mask) {
741 		port->ops->unthrottle(port);
742 		mask &= ~port->status;
743 	}
744 
745 	if (mask & UPSTAT_AUTORTS)
746 		uart_set_mctrl(port, TIOCM_RTS);
747 
748 	if (mask & UPSTAT_AUTOXOFF)
749 		uart_send_xchar(tty, START_CHAR(tty));
750 
751 	uart_port_deref(port);
752 }
753 
754 static int uart_get_info(struct tty_port *port, struct serial_struct *retinfo)
755 {
756 	struct uart_state *state = container_of(port, struct uart_state, port);
757 	struct uart_port *uport;
758 	int ret = -ENODEV;
759 
760 	memset(retinfo, 0, sizeof(*retinfo));
761 
762 	/*
763 	 * Ensure the state we copy is consistent and no hardware changes
764 	 * occur as we go
765 	 */
766 	mutex_lock(&port->mutex);
767 	uport = uart_port_check(state);
768 	if (!uport)
769 		goto out;
770 
771 	retinfo->type	    = uport->type;
772 	retinfo->line	    = uport->line;
773 	retinfo->port	    = uport->iobase;
774 	if (HIGH_BITS_OFFSET)
775 		retinfo->port_high = (long) uport->iobase >> HIGH_BITS_OFFSET;
776 	retinfo->irq		    = uport->irq;
777 	retinfo->flags	    = (__force int)uport->flags;
778 	retinfo->xmit_fifo_size  = uport->fifosize;
779 	retinfo->baud_base	    = uport->uartclk / 16;
780 	retinfo->close_delay	    = jiffies_to_msecs(port->close_delay) / 10;
781 	retinfo->closing_wait    = port->closing_wait == ASYNC_CLOSING_WAIT_NONE ?
782 				ASYNC_CLOSING_WAIT_NONE :
783 				jiffies_to_msecs(port->closing_wait) / 10;
784 	retinfo->custom_divisor  = uport->custom_divisor;
785 	retinfo->hub6	    = uport->hub6;
786 	retinfo->io_type         = uport->iotype;
787 	retinfo->iomem_reg_shift = uport->regshift;
788 	retinfo->iomem_base      = (void *)(unsigned long)uport->mapbase;
789 
790 	ret = 0;
791 out:
792 	mutex_unlock(&port->mutex);
793 	return ret;
794 }
795 
796 static int uart_get_info_user(struct tty_struct *tty,
797 			 struct serial_struct *ss)
798 {
799 	struct uart_state *state = tty->driver_data;
800 	struct tty_port *port = &state->port;
801 
802 	return uart_get_info(port, ss) < 0 ? -EIO : 0;
803 }
804 
805 static int uart_set_info(struct tty_struct *tty, struct tty_port *port,
806 			 struct uart_state *state,
807 			 struct serial_struct *new_info)
808 {
809 	struct uart_port *uport = uart_port_check(state);
810 	unsigned long new_port;
811 	unsigned int change_irq, change_port, closing_wait;
812 	unsigned int old_custom_divisor, close_delay;
813 	upf_t old_flags, new_flags;
814 	int retval = 0;
815 
816 	if (!uport)
817 		return -EIO;
818 
819 	new_port = new_info->port;
820 	if (HIGH_BITS_OFFSET)
821 		new_port += (unsigned long) new_info->port_high << HIGH_BITS_OFFSET;
822 
823 	new_info->irq = irq_canonicalize(new_info->irq);
824 	close_delay = msecs_to_jiffies(new_info->close_delay * 10);
825 	closing_wait = new_info->closing_wait == ASYNC_CLOSING_WAIT_NONE ?
826 			ASYNC_CLOSING_WAIT_NONE :
827 			msecs_to_jiffies(new_info->closing_wait * 10);
828 
829 
830 	change_irq  = !(uport->flags & UPF_FIXED_PORT)
831 		&& new_info->irq != uport->irq;
832 
833 	/*
834 	 * Since changing the 'type' of the port changes its resource
835 	 * allocations, we should treat type changes the same as
836 	 * IO port changes.
837 	 */
838 	change_port = !(uport->flags & UPF_FIXED_PORT)
839 		&& (new_port != uport->iobase ||
840 		    (unsigned long)new_info->iomem_base != uport->mapbase ||
841 		    new_info->hub6 != uport->hub6 ||
842 		    new_info->io_type != uport->iotype ||
843 		    new_info->iomem_reg_shift != uport->regshift ||
844 		    new_info->type != uport->type);
845 
846 	old_flags = uport->flags;
847 	new_flags = (__force upf_t)new_info->flags;
848 	old_custom_divisor = uport->custom_divisor;
849 
850 	if (!capable(CAP_SYS_ADMIN)) {
851 		retval = -EPERM;
852 		if (change_irq || change_port ||
853 		    (new_info->baud_base != uport->uartclk / 16) ||
854 		    (close_delay != port->close_delay) ||
855 		    (closing_wait != port->closing_wait) ||
856 		    (new_info->xmit_fifo_size &&
857 		     new_info->xmit_fifo_size != uport->fifosize) ||
858 		    (((new_flags ^ old_flags) & ~UPF_USR_MASK) != 0))
859 			goto exit;
860 		uport->flags = ((uport->flags & ~UPF_USR_MASK) |
861 			       (new_flags & UPF_USR_MASK));
862 		uport->custom_divisor = new_info->custom_divisor;
863 		goto check_and_exit;
864 	}
865 
866 	retval = security_locked_down(LOCKDOWN_TIOCSSERIAL);
867 	if (retval && (change_irq || change_port))
868 		goto exit;
869 
870 	/*
871 	 * Ask the low level driver to verify the settings.
872 	 */
873 	if (uport->ops->verify_port)
874 		retval = uport->ops->verify_port(uport, new_info);
875 
876 	if ((new_info->irq >= nr_irqs) || (new_info->irq < 0) ||
877 	    (new_info->baud_base < 9600))
878 		retval = -EINVAL;
879 
880 	if (retval)
881 		goto exit;
882 
883 	if (change_port || change_irq) {
884 		retval = -EBUSY;
885 
886 		/*
887 		 * Make sure that we are the sole user of this port.
888 		 */
889 		if (tty_port_users(port) > 1)
890 			goto exit;
891 
892 		/*
893 		 * We need to shutdown the serial port at the old
894 		 * port/type/irq combination.
895 		 */
896 		uart_shutdown(tty, state);
897 	}
898 
899 	if (change_port) {
900 		unsigned long old_iobase, old_mapbase;
901 		unsigned int old_type, old_iotype, old_hub6, old_shift;
902 
903 		old_iobase = uport->iobase;
904 		old_mapbase = uport->mapbase;
905 		old_type = uport->type;
906 		old_hub6 = uport->hub6;
907 		old_iotype = uport->iotype;
908 		old_shift = uport->regshift;
909 
910 		/*
911 		 * Free and release old regions
912 		 */
913 		if (old_type != PORT_UNKNOWN && uport->ops->release_port)
914 			uport->ops->release_port(uport);
915 
916 		uport->iobase = new_port;
917 		uport->type = new_info->type;
918 		uport->hub6 = new_info->hub6;
919 		uport->iotype = new_info->io_type;
920 		uport->regshift = new_info->iomem_reg_shift;
921 		uport->mapbase = (unsigned long)new_info->iomem_base;
922 
923 		/*
924 		 * Claim and map the new regions
925 		 */
926 		if (uport->type != PORT_UNKNOWN && uport->ops->request_port) {
927 			retval = uport->ops->request_port(uport);
928 		} else {
929 			/* Always success - Jean II */
930 			retval = 0;
931 		}
932 
933 		/*
934 		 * If we fail to request resources for the
935 		 * new port, try to restore the old settings.
936 		 */
937 		if (retval) {
938 			uport->iobase = old_iobase;
939 			uport->type = old_type;
940 			uport->hub6 = old_hub6;
941 			uport->iotype = old_iotype;
942 			uport->regshift = old_shift;
943 			uport->mapbase = old_mapbase;
944 
945 			if (old_type != PORT_UNKNOWN) {
946 				retval = uport->ops->request_port(uport);
947 				/*
948 				 * If we failed to restore the old settings,
949 				 * we fail like this.
950 				 */
951 				if (retval)
952 					uport->type = PORT_UNKNOWN;
953 
954 				/*
955 				 * We failed anyway.
956 				 */
957 				retval = -EBUSY;
958 			}
959 
960 			/* Added to return the correct error -Ram Gupta */
961 			goto exit;
962 		}
963 	}
964 
965 	if (change_irq)
966 		uport->irq      = new_info->irq;
967 	if (!(uport->flags & UPF_FIXED_PORT))
968 		uport->uartclk  = new_info->baud_base * 16;
969 	uport->flags            = (uport->flags & ~UPF_CHANGE_MASK) |
970 				 (new_flags & UPF_CHANGE_MASK);
971 	uport->custom_divisor   = new_info->custom_divisor;
972 	port->close_delay     = close_delay;
973 	port->closing_wait    = closing_wait;
974 	if (new_info->xmit_fifo_size)
975 		uport->fifosize = new_info->xmit_fifo_size;
976 	port->low_latency = (uport->flags & UPF_LOW_LATENCY) ? 1 : 0;
977 
978  check_and_exit:
979 	retval = 0;
980 	if (uport->type == PORT_UNKNOWN)
981 		goto exit;
982 	if (tty_port_initialized(port)) {
983 		if (((old_flags ^ uport->flags) & UPF_SPD_MASK) ||
984 		    old_custom_divisor != uport->custom_divisor) {
985 			/*
986 			 * If they're setting up a custom divisor or speed,
987 			 * instead of clearing it, then bitch about it.
988 			 */
989 			if (uport->flags & UPF_SPD_MASK) {
990 				dev_notice_ratelimited(uport->dev,
991 				       "%s sets custom speed on %s. This is deprecated.\n",
992 				      current->comm,
993 				      tty_name(port->tty));
994 			}
995 			uart_change_speed(tty, state, NULL);
996 		}
997 	} else {
998 		retval = uart_startup(tty, state, 1);
999 		if (retval == 0)
1000 			tty_port_set_initialized(port, true);
1001 		if (retval > 0)
1002 			retval = 0;
1003 	}
1004  exit:
1005 	return retval;
1006 }
1007 
1008 static int uart_set_info_user(struct tty_struct *tty, struct serial_struct *ss)
1009 {
1010 	struct uart_state *state = tty->driver_data;
1011 	struct tty_port *port = &state->port;
1012 	int retval;
1013 
1014 	down_write(&tty->termios_rwsem);
1015 	/*
1016 	 * This semaphore protects port->count.  It is also
1017 	 * very useful to prevent opens.  Also, take the
1018 	 * port configuration semaphore to make sure that a
1019 	 * module insertion/removal doesn't change anything
1020 	 * under us.
1021 	 */
1022 	mutex_lock(&port->mutex);
1023 	retval = uart_set_info(tty, port, state, ss);
1024 	mutex_unlock(&port->mutex);
1025 	up_write(&tty->termios_rwsem);
1026 	return retval;
1027 }
1028 
1029 /**
1030  *	uart_get_lsr_info	-	get line status register info
1031  *	@tty: tty associated with the UART
1032  *	@state: UART being queried
1033  *	@value: returned modem value
1034  */
1035 static int uart_get_lsr_info(struct tty_struct *tty,
1036 			struct uart_state *state, unsigned int __user *value)
1037 {
1038 	struct uart_port *uport = uart_port_check(state);
1039 	unsigned int result;
1040 
1041 	result = uport->ops->tx_empty(uport);
1042 
1043 	/*
1044 	 * If we're about to load something into the transmit
1045 	 * register, we'll pretend the transmitter isn't empty to
1046 	 * avoid a race condition (depending on when the transmit
1047 	 * interrupt happens).
1048 	 */
1049 	if (uport->x_char ||
1050 	    ((uart_circ_chars_pending(&state->xmit) > 0) &&
1051 	     !uart_tx_stopped(uport)))
1052 		result &= ~TIOCSER_TEMT;
1053 
1054 	return put_user(result, value);
1055 }
1056 
1057 static int uart_tiocmget(struct tty_struct *tty)
1058 {
1059 	struct uart_state *state = tty->driver_data;
1060 	struct tty_port *port = &state->port;
1061 	struct uart_port *uport;
1062 	int result = -EIO;
1063 
1064 	mutex_lock(&port->mutex);
1065 	uport = uart_port_check(state);
1066 	if (!uport)
1067 		goto out;
1068 
1069 	if (!tty_io_error(tty)) {
1070 		result = uport->mctrl;
1071 		spin_lock_irq(&uport->lock);
1072 		result |= uport->ops->get_mctrl(uport);
1073 		spin_unlock_irq(&uport->lock);
1074 	}
1075 out:
1076 	mutex_unlock(&port->mutex);
1077 	return result;
1078 }
1079 
1080 static int
1081 uart_tiocmset(struct tty_struct *tty, unsigned int set, unsigned int clear)
1082 {
1083 	struct uart_state *state = tty->driver_data;
1084 	struct tty_port *port = &state->port;
1085 	struct uart_port *uport;
1086 	int ret = -EIO;
1087 
1088 	mutex_lock(&port->mutex);
1089 	uport = uart_port_check(state);
1090 	if (!uport)
1091 		goto out;
1092 
1093 	if (!tty_io_error(tty)) {
1094 		uart_update_mctrl(uport, set, clear);
1095 		ret = 0;
1096 	}
1097 out:
1098 	mutex_unlock(&port->mutex);
1099 	return ret;
1100 }
1101 
1102 static int uart_break_ctl(struct tty_struct *tty, int break_state)
1103 {
1104 	struct uart_state *state = tty->driver_data;
1105 	struct tty_port *port = &state->port;
1106 	struct uart_port *uport;
1107 	int ret = -EIO;
1108 
1109 	mutex_lock(&port->mutex);
1110 	uport = uart_port_check(state);
1111 	if (!uport)
1112 		goto out;
1113 
1114 	if (uport->type != PORT_UNKNOWN && uport->ops->break_ctl)
1115 		uport->ops->break_ctl(uport, break_state);
1116 	ret = 0;
1117 out:
1118 	mutex_unlock(&port->mutex);
1119 	return ret;
1120 }
1121 
1122 static int uart_do_autoconfig(struct tty_struct *tty,struct uart_state *state)
1123 {
1124 	struct tty_port *port = &state->port;
1125 	struct uart_port *uport;
1126 	int flags, ret;
1127 
1128 	if (!capable(CAP_SYS_ADMIN))
1129 		return -EPERM;
1130 
1131 	/*
1132 	 * Take the per-port semaphore.  This prevents count from
1133 	 * changing, and hence any extra opens of the port while
1134 	 * we're auto-configuring.
1135 	 */
1136 	if (mutex_lock_interruptible(&port->mutex))
1137 		return -ERESTARTSYS;
1138 
1139 	uport = uart_port_check(state);
1140 	if (!uport) {
1141 		ret = -EIO;
1142 		goto out;
1143 	}
1144 
1145 	ret = -EBUSY;
1146 	if (tty_port_users(port) == 1) {
1147 		uart_shutdown(tty, state);
1148 
1149 		/*
1150 		 * If we already have a port type configured,
1151 		 * we must release its resources.
1152 		 */
1153 		if (uport->type != PORT_UNKNOWN && uport->ops->release_port)
1154 			uport->ops->release_port(uport);
1155 
1156 		flags = UART_CONFIG_TYPE;
1157 		if (uport->flags & UPF_AUTO_IRQ)
1158 			flags |= UART_CONFIG_IRQ;
1159 
1160 		/*
1161 		 * This will claim the ports resources if
1162 		 * a port is found.
1163 		 */
1164 		uport->ops->config_port(uport, flags);
1165 
1166 		ret = uart_startup(tty, state, 1);
1167 		if (ret == 0)
1168 			tty_port_set_initialized(port, true);
1169 		if (ret > 0)
1170 			ret = 0;
1171 	}
1172 out:
1173 	mutex_unlock(&port->mutex);
1174 	return ret;
1175 }
1176 
1177 static void uart_enable_ms(struct uart_port *uport)
1178 {
1179 	/*
1180 	 * Force modem status interrupts on
1181 	 */
1182 	if (uport->ops->enable_ms)
1183 		uport->ops->enable_ms(uport);
1184 }
1185 
1186 /*
1187  * Wait for any of the 4 modem inputs (DCD,RI,DSR,CTS) to change
1188  * - mask passed in arg for lines of interest
1189  *   (use |'ed TIOCM_RNG/DSR/CD/CTS for masking)
1190  * Caller should use TIOCGICOUNT to see which one it was
1191  *
1192  * FIXME: This wants extracting into a common all driver implementation
1193  * of TIOCMWAIT using tty_port.
1194  */
1195 static int uart_wait_modem_status(struct uart_state *state, unsigned long arg)
1196 {
1197 	struct uart_port *uport;
1198 	struct tty_port *port = &state->port;
1199 	DECLARE_WAITQUEUE(wait, current);
1200 	struct uart_icount cprev, cnow;
1201 	int ret;
1202 
1203 	/*
1204 	 * note the counters on entry
1205 	 */
1206 	uport = uart_port_ref(state);
1207 	if (!uport)
1208 		return -EIO;
1209 	spin_lock_irq(&uport->lock);
1210 	memcpy(&cprev, &uport->icount, sizeof(struct uart_icount));
1211 	uart_enable_ms(uport);
1212 	spin_unlock_irq(&uport->lock);
1213 
1214 	add_wait_queue(&port->delta_msr_wait, &wait);
1215 	for (;;) {
1216 		spin_lock_irq(&uport->lock);
1217 		memcpy(&cnow, &uport->icount, sizeof(struct uart_icount));
1218 		spin_unlock_irq(&uport->lock);
1219 
1220 		set_current_state(TASK_INTERRUPTIBLE);
1221 
1222 		if (((arg & TIOCM_RNG) && (cnow.rng != cprev.rng)) ||
1223 		    ((arg & TIOCM_DSR) && (cnow.dsr != cprev.dsr)) ||
1224 		    ((arg & TIOCM_CD)  && (cnow.dcd != cprev.dcd)) ||
1225 		    ((arg & TIOCM_CTS) && (cnow.cts != cprev.cts))) {
1226 			ret = 0;
1227 			break;
1228 		}
1229 
1230 		schedule();
1231 
1232 		/* see if a signal did it */
1233 		if (signal_pending(current)) {
1234 			ret = -ERESTARTSYS;
1235 			break;
1236 		}
1237 
1238 		cprev = cnow;
1239 	}
1240 	__set_current_state(TASK_RUNNING);
1241 	remove_wait_queue(&port->delta_msr_wait, &wait);
1242 	uart_port_deref(uport);
1243 
1244 	return ret;
1245 }
1246 
1247 /*
1248  * Get counter of input serial line interrupts (DCD,RI,DSR,CTS)
1249  * Return: write counters to the user passed counter struct
1250  * NB: both 1->0 and 0->1 transitions are counted except for
1251  *     RI where only 0->1 is counted.
1252  */
1253 static int uart_get_icount(struct tty_struct *tty,
1254 			  struct serial_icounter_struct *icount)
1255 {
1256 	struct uart_state *state = tty->driver_data;
1257 	struct uart_icount cnow;
1258 	struct uart_port *uport;
1259 
1260 	uport = uart_port_ref(state);
1261 	if (!uport)
1262 		return -EIO;
1263 	spin_lock_irq(&uport->lock);
1264 	memcpy(&cnow, &uport->icount, sizeof(struct uart_icount));
1265 	spin_unlock_irq(&uport->lock);
1266 	uart_port_deref(uport);
1267 
1268 	icount->cts         = cnow.cts;
1269 	icount->dsr         = cnow.dsr;
1270 	icount->rng         = cnow.rng;
1271 	icount->dcd         = cnow.dcd;
1272 	icount->rx          = cnow.rx;
1273 	icount->tx          = cnow.tx;
1274 	icount->frame       = cnow.frame;
1275 	icount->overrun     = cnow.overrun;
1276 	icount->parity      = cnow.parity;
1277 	icount->brk         = cnow.brk;
1278 	icount->buf_overrun = cnow.buf_overrun;
1279 
1280 	return 0;
1281 }
1282 
1283 static int uart_get_rs485_config(struct uart_port *port,
1284 			 struct serial_rs485 __user *rs485)
1285 {
1286 	unsigned long flags;
1287 	struct serial_rs485 aux;
1288 
1289 	spin_lock_irqsave(&port->lock, flags);
1290 	aux = port->rs485;
1291 	spin_unlock_irqrestore(&port->lock, flags);
1292 
1293 	if (copy_to_user(rs485, &aux, sizeof(aux)))
1294 		return -EFAULT;
1295 
1296 	return 0;
1297 }
1298 
1299 static int uart_set_rs485_config(struct uart_port *port,
1300 			 struct serial_rs485 __user *rs485_user)
1301 {
1302 	struct serial_rs485 rs485;
1303 	int ret;
1304 	unsigned long flags;
1305 
1306 	if (!port->rs485_config)
1307 		return -ENOIOCTLCMD;
1308 
1309 	if (copy_from_user(&rs485, rs485_user, sizeof(*rs485_user)))
1310 		return -EFAULT;
1311 
1312 	spin_lock_irqsave(&port->lock, flags);
1313 	ret = port->rs485_config(port, &rs485);
1314 	spin_unlock_irqrestore(&port->lock, flags);
1315 	if (ret)
1316 		return ret;
1317 
1318 	if (copy_to_user(rs485_user, &port->rs485, sizeof(port->rs485)))
1319 		return -EFAULT;
1320 
1321 	return 0;
1322 }
1323 
1324 static int uart_get_iso7816_config(struct uart_port *port,
1325 				   struct serial_iso7816 __user *iso7816)
1326 {
1327 	unsigned long flags;
1328 	struct serial_iso7816 aux;
1329 
1330 	if (!port->iso7816_config)
1331 		return -ENOIOCTLCMD;
1332 
1333 	spin_lock_irqsave(&port->lock, flags);
1334 	aux = port->iso7816;
1335 	spin_unlock_irqrestore(&port->lock, flags);
1336 
1337 	if (copy_to_user(iso7816, &aux, sizeof(aux)))
1338 		return -EFAULT;
1339 
1340 	return 0;
1341 }
1342 
1343 static int uart_set_iso7816_config(struct uart_port *port,
1344 				   struct serial_iso7816 __user *iso7816_user)
1345 {
1346 	struct serial_iso7816 iso7816;
1347 	int i, ret;
1348 	unsigned long flags;
1349 
1350 	if (!port->iso7816_config)
1351 		return -ENOIOCTLCMD;
1352 
1353 	if (copy_from_user(&iso7816, iso7816_user, sizeof(*iso7816_user)))
1354 		return -EFAULT;
1355 
1356 	/*
1357 	 * There are 5 words reserved for future use. Check that userspace
1358 	 * doesn't put stuff in there to prevent breakages in the future.
1359 	 */
1360 	for (i = 0; i < 5; i++)
1361 		if (iso7816.reserved[i])
1362 			return -EINVAL;
1363 
1364 	spin_lock_irqsave(&port->lock, flags);
1365 	ret = port->iso7816_config(port, &iso7816);
1366 	spin_unlock_irqrestore(&port->lock, flags);
1367 	if (ret)
1368 		return ret;
1369 
1370 	if (copy_to_user(iso7816_user, &port->iso7816, sizeof(port->iso7816)))
1371 		return -EFAULT;
1372 
1373 	return 0;
1374 }
1375 
1376 /*
1377  * Called via sys_ioctl.  We can use spin_lock_irq() here.
1378  */
1379 static int
1380 uart_ioctl(struct tty_struct *tty, unsigned int cmd, unsigned long arg)
1381 {
1382 	struct uart_state *state = tty->driver_data;
1383 	struct tty_port *port = &state->port;
1384 	struct uart_port *uport;
1385 	void __user *uarg = (void __user *)arg;
1386 	int ret = -ENOIOCTLCMD;
1387 
1388 
1389 	/*
1390 	 * These ioctls don't rely on the hardware to be present.
1391 	 */
1392 	switch (cmd) {
1393 	case TIOCSERCONFIG:
1394 		down_write(&tty->termios_rwsem);
1395 		ret = uart_do_autoconfig(tty, state);
1396 		up_write(&tty->termios_rwsem);
1397 		break;
1398 	}
1399 
1400 	if (ret != -ENOIOCTLCMD)
1401 		goto out;
1402 
1403 	if (tty_io_error(tty)) {
1404 		ret = -EIO;
1405 		goto out;
1406 	}
1407 
1408 	/*
1409 	 * The following should only be used when hardware is present.
1410 	 */
1411 	switch (cmd) {
1412 	case TIOCMIWAIT:
1413 		ret = uart_wait_modem_status(state, arg);
1414 		break;
1415 	}
1416 
1417 	if (ret != -ENOIOCTLCMD)
1418 		goto out;
1419 
1420 	mutex_lock(&port->mutex);
1421 	uport = uart_port_check(state);
1422 
1423 	if (!uport || tty_io_error(tty)) {
1424 		ret = -EIO;
1425 		goto out_up;
1426 	}
1427 
1428 	/*
1429 	 * All these rely on hardware being present and need to be
1430 	 * protected against the tty being hung up.
1431 	 */
1432 
1433 	switch (cmd) {
1434 	case TIOCSERGETLSR: /* Get line status register */
1435 		ret = uart_get_lsr_info(tty, state, uarg);
1436 		break;
1437 
1438 	case TIOCGRS485:
1439 		ret = uart_get_rs485_config(uport, uarg);
1440 		break;
1441 
1442 	case TIOCSRS485:
1443 		ret = uart_set_rs485_config(uport, uarg);
1444 		break;
1445 
1446 	case TIOCSISO7816:
1447 		ret = uart_set_iso7816_config(state->uart_port, uarg);
1448 		break;
1449 
1450 	case TIOCGISO7816:
1451 		ret = uart_get_iso7816_config(state->uart_port, uarg);
1452 		break;
1453 	default:
1454 		if (uport->ops->ioctl)
1455 			ret = uport->ops->ioctl(uport, cmd, arg);
1456 		break;
1457 	}
1458 out_up:
1459 	mutex_unlock(&port->mutex);
1460 out:
1461 	return ret;
1462 }
1463 
1464 static void uart_set_ldisc(struct tty_struct *tty)
1465 {
1466 	struct uart_state *state = tty->driver_data;
1467 	struct uart_port *uport;
1468 
1469 	mutex_lock(&state->port.mutex);
1470 	uport = uart_port_check(state);
1471 	if (uport && uport->ops->set_ldisc)
1472 		uport->ops->set_ldisc(uport, &tty->termios);
1473 	mutex_unlock(&state->port.mutex);
1474 }
1475 
1476 static void uart_set_termios(struct tty_struct *tty,
1477 						struct ktermios *old_termios)
1478 {
1479 	struct uart_state *state = tty->driver_data;
1480 	struct uart_port *uport;
1481 	unsigned int cflag = tty->termios.c_cflag;
1482 	unsigned int iflag_mask = IGNBRK|BRKINT|IGNPAR|PARMRK|INPCK;
1483 	bool sw_changed = false;
1484 
1485 	mutex_lock(&state->port.mutex);
1486 	uport = uart_port_check(state);
1487 	if (!uport)
1488 		goto out;
1489 
1490 	/*
1491 	 * Drivers doing software flow control also need to know
1492 	 * about changes to these input settings.
1493 	 */
1494 	if (uport->flags & UPF_SOFT_FLOW) {
1495 		iflag_mask |= IXANY|IXON|IXOFF;
1496 		sw_changed =
1497 		   tty->termios.c_cc[VSTART] != old_termios->c_cc[VSTART] ||
1498 		   tty->termios.c_cc[VSTOP] != old_termios->c_cc[VSTOP];
1499 	}
1500 
1501 	/*
1502 	 * These are the bits that are used to setup various
1503 	 * flags in the low level driver. We can ignore the Bfoo
1504 	 * bits in c_cflag; c_[io]speed will always be set
1505 	 * appropriately by set_termios() in tty_ioctl.c
1506 	 */
1507 	if ((cflag ^ old_termios->c_cflag) == 0 &&
1508 	    tty->termios.c_ospeed == old_termios->c_ospeed &&
1509 	    tty->termios.c_ispeed == old_termios->c_ispeed &&
1510 	    ((tty->termios.c_iflag ^ old_termios->c_iflag) & iflag_mask) == 0 &&
1511 	    !sw_changed) {
1512 		goto out;
1513 	}
1514 
1515 	uart_change_speed(tty, state, old_termios);
1516 	/* reload cflag from termios; port driver may have overridden flags */
1517 	cflag = tty->termios.c_cflag;
1518 
1519 	/* Handle transition to B0 status */
1520 	if ((old_termios->c_cflag & CBAUD) && !(cflag & CBAUD))
1521 		uart_clear_mctrl(uport, TIOCM_RTS | TIOCM_DTR);
1522 	/* Handle transition away from B0 status */
1523 	else if (!(old_termios->c_cflag & CBAUD) && (cflag & CBAUD)) {
1524 		unsigned int mask = TIOCM_DTR;
1525 		if (!(cflag & CRTSCTS) || !tty_throttled(tty))
1526 			mask |= TIOCM_RTS;
1527 		uart_set_mctrl(uport, mask);
1528 	}
1529 out:
1530 	mutex_unlock(&state->port.mutex);
1531 }
1532 
1533 /*
1534  * Calls to uart_close() are serialised via the tty_lock in
1535  *   drivers/tty/tty_io.c:tty_release()
1536  *   drivers/tty/tty_io.c:do_tty_hangup()
1537  */
1538 static void uart_close(struct tty_struct *tty, struct file *filp)
1539 {
1540 	struct uart_state *state = tty->driver_data;
1541 
1542 	if (!state) {
1543 		struct uart_driver *drv = tty->driver->driver_state;
1544 		struct tty_port *port;
1545 
1546 		state = drv->state + tty->index;
1547 		port = &state->port;
1548 		spin_lock_irq(&port->lock);
1549 		--port->count;
1550 		spin_unlock_irq(&port->lock);
1551 		return;
1552 	}
1553 
1554 	pr_debug("uart_close(%d) called\n", tty->index);
1555 
1556 	tty_port_close(tty->port, tty, filp);
1557 }
1558 
1559 static void uart_tty_port_shutdown(struct tty_port *port)
1560 {
1561 	struct uart_state *state = container_of(port, struct uart_state, port);
1562 	struct uart_port *uport = uart_port_check(state);
1563 
1564 	/*
1565 	 * At this point, we stop accepting input.  To do this, we
1566 	 * disable the receive line status interrupts.
1567 	 */
1568 	if (WARN(!uport, "detached port still initialized!\n"))
1569 		return;
1570 
1571 	spin_lock_irq(&uport->lock);
1572 	uport->ops->stop_rx(uport);
1573 	spin_unlock_irq(&uport->lock);
1574 
1575 	uart_port_shutdown(port);
1576 
1577 	/*
1578 	 * It's possible for shutdown to be called after suspend if we get
1579 	 * a DCD drop (hangup) at just the right time.  Clear suspended bit so
1580 	 * we don't try to resume a port that has been shutdown.
1581 	 */
1582 	tty_port_set_suspended(port, 0);
1583 
1584 	uart_change_pm(state, UART_PM_STATE_OFF);
1585 
1586 }
1587 
1588 static void uart_wait_until_sent(struct tty_struct *tty, int timeout)
1589 {
1590 	struct uart_state *state = tty->driver_data;
1591 	struct uart_port *port;
1592 	unsigned long char_time, expire;
1593 
1594 	port = uart_port_ref(state);
1595 	if (!port)
1596 		return;
1597 
1598 	if (port->type == PORT_UNKNOWN || port->fifosize == 0) {
1599 		uart_port_deref(port);
1600 		return;
1601 	}
1602 
1603 	/*
1604 	 * Set the check interval to be 1/5 of the estimated time to
1605 	 * send a single character, and make it at least 1.  The check
1606 	 * interval should also be less than the timeout.
1607 	 *
1608 	 * Note: we have to use pretty tight timings here to satisfy
1609 	 * the NIST-PCTS.
1610 	 */
1611 	char_time = (port->timeout - HZ/50) / port->fifosize;
1612 	char_time = char_time / 5;
1613 	if (char_time == 0)
1614 		char_time = 1;
1615 	if (timeout && timeout < char_time)
1616 		char_time = timeout;
1617 
1618 	/*
1619 	 * If the transmitter hasn't cleared in twice the approximate
1620 	 * amount of time to send the entire FIFO, it probably won't
1621 	 * ever clear.  This assumes the UART isn't doing flow
1622 	 * control, which is currently the case.  Hence, if it ever
1623 	 * takes longer than port->timeout, this is probably due to a
1624 	 * UART bug of some kind.  So, we clamp the timeout parameter at
1625 	 * 2*port->timeout.
1626 	 */
1627 	if (timeout == 0 || timeout > 2 * port->timeout)
1628 		timeout = 2 * port->timeout;
1629 
1630 	expire = jiffies + timeout;
1631 
1632 	pr_debug("uart_wait_until_sent(%d), jiffies=%lu, expire=%lu...\n",
1633 		port->line, jiffies, expire);
1634 
1635 	/*
1636 	 * Check whether the transmitter is empty every 'char_time'.
1637 	 * 'timeout' / 'expire' give us the maximum amount of time
1638 	 * we wait.
1639 	 */
1640 	while (!port->ops->tx_empty(port)) {
1641 		msleep_interruptible(jiffies_to_msecs(char_time));
1642 		if (signal_pending(current))
1643 			break;
1644 		if (time_after(jiffies, expire))
1645 			break;
1646 	}
1647 	uart_port_deref(port);
1648 }
1649 
1650 /*
1651  * Calls to uart_hangup() are serialised by the tty_lock in
1652  *   drivers/tty/tty_io.c:do_tty_hangup()
1653  * This runs from a workqueue and can sleep for a _short_ time only.
1654  */
1655 static void uart_hangup(struct tty_struct *tty)
1656 {
1657 	struct uart_state *state = tty->driver_data;
1658 	struct tty_port *port = &state->port;
1659 	struct uart_port *uport;
1660 	unsigned long flags;
1661 
1662 	pr_debug("uart_hangup(%d)\n", tty->index);
1663 
1664 	mutex_lock(&port->mutex);
1665 	uport = uart_port_check(state);
1666 	WARN(!uport, "hangup of detached port!\n");
1667 
1668 	if (tty_port_active(port)) {
1669 		uart_flush_buffer(tty);
1670 		uart_shutdown(tty, state);
1671 		spin_lock_irqsave(&port->lock, flags);
1672 		port->count = 0;
1673 		spin_unlock_irqrestore(&port->lock, flags);
1674 		tty_port_set_active(port, 0);
1675 		tty_port_tty_set(port, NULL);
1676 		if (uport && !uart_console(uport))
1677 			uart_change_pm(state, UART_PM_STATE_OFF);
1678 		wake_up_interruptible(&port->open_wait);
1679 		wake_up_interruptible(&port->delta_msr_wait);
1680 	}
1681 	mutex_unlock(&port->mutex);
1682 }
1683 
1684 /* uport == NULL if uart_port has already been removed */
1685 static void uart_port_shutdown(struct tty_port *port)
1686 {
1687 	struct uart_state *state = container_of(port, struct uart_state, port);
1688 	struct uart_port *uport = uart_port_check(state);
1689 
1690 	/*
1691 	 * clear delta_msr_wait queue to avoid mem leaks: we may free
1692 	 * the irq here so the queue might never be woken up.  Note
1693 	 * that we won't end up waiting on delta_msr_wait again since
1694 	 * any outstanding file descriptors should be pointing at
1695 	 * hung_up_tty_fops now.
1696 	 */
1697 	wake_up_interruptible(&port->delta_msr_wait);
1698 
1699 	/*
1700 	 * Free the IRQ and disable the port.
1701 	 */
1702 	if (uport)
1703 		uport->ops->shutdown(uport);
1704 
1705 	/*
1706 	 * Ensure that the IRQ handler isn't running on another CPU.
1707 	 */
1708 	if (uport)
1709 		synchronize_irq(uport->irq);
1710 }
1711 
1712 static int uart_carrier_raised(struct tty_port *port)
1713 {
1714 	struct uart_state *state = container_of(port, struct uart_state, port);
1715 	struct uart_port *uport;
1716 	int mctrl;
1717 
1718 	uport = uart_port_ref(state);
1719 	/*
1720 	 * Should never observe uport == NULL since checks for hangup should
1721 	 * abort the tty_port_block_til_ready() loop before checking for carrier
1722 	 * raised -- but report carrier raised if it does anyway so open will
1723 	 * continue and not sleep
1724 	 */
1725 	if (WARN_ON(!uport))
1726 		return 1;
1727 	spin_lock_irq(&uport->lock);
1728 	uart_enable_ms(uport);
1729 	mctrl = uport->ops->get_mctrl(uport);
1730 	spin_unlock_irq(&uport->lock);
1731 	uart_port_deref(uport);
1732 	if (mctrl & TIOCM_CAR)
1733 		return 1;
1734 	return 0;
1735 }
1736 
1737 static void uart_dtr_rts(struct tty_port *port, int raise)
1738 {
1739 	struct uart_state *state = container_of(port, struct uart_state, port);
1740 	struct uart_port *uport;
1741 
1742 	uport = uart_port_ref(state);
1743 	if (!uport)
1744 		return;
1745 	uart_port_dtr_rts(uport, raise);
1746 	uart_port_deref(uport);
1747 }
1748 
1749 static int uart_install(struct tty_driver *driver, struct tty_struct *tty)
1750 {
1751 	struct uart_driver *drv = driver->driver_state;
1752 	struct uart_state *state = drv->state + tty->index;
1753 
1754 	tty->driver_data = state;
1755 
1756 	return tty_standard_install(driver, tty);
1757 }
1758 
1759 /*
1760  * Calls to uart_open are serialised by the tty_lock in
1761  *   drivers/tty/tty_io.c:tty_open()
1762  * Note that if this fails, then uart_close() _will_ be called.
1763  *
1764  * In time, we want to scrap the "opening nonpresent ports"
1765  * behaviour and implement an alternative way for setserial
1766  * to set base addresses/ports/types.  This will allow us to
1767  * get rid of a certain amount of extra tests.
1768  */
1769 static int uart_open(struct tty_struct *tty, struct file *filp)
1770 {
1771 	struct uart_state *state = tty->driver_data;
1772 	int retval;
1773 
1774 	retval = tty_port_open(&state->port, tty, filp);
1775 	if (retval > 0)
1776 		retval = 0;
1777 
1778 	return retval;
1779 }
1780 
1781 static int uart_port_activate(struct tty_port *port, struct tty_struct *tty)
1782 {
1783 	struct uart_state *state = container_of(port, struct uart_state, port);
1784 	struct uart_port *uport;
1785 	int ret;
1786 
1787 	uport = uart_port_check(state);
1788 	if (!uport || uport->flags & UPF_DEAD)
1789 		return -ENXIO;
1790 
1791 	port->low_latency = (uport->flags & UPF_LOW_LATENCY) ? 1 : 0;
1792 
1793 	/*
1794 	 * Start up the serial port.
1795 	 */
1796 	ret = uart_startup(tty, state, 0);
1797 	if (ret > 0)
1798 		tty_port_set_active(port, 1);
1799 
1800 	return ret;
1801 }
1802 
1803 static const char *uart_type(struct uart_port *port)
1804 {
1805 	const char *str = NULL;
1806 
1807 	if (port->ops->type)
1808 		str = port->ops->type(port);
1809 
1810 	if (!str)
1811 		str = "unknown";
1812 
1813 	return str;
1814 }
1815 
1816 #ifdef CONFIG_PROC_FS
1817 
1818 static void uart_line_info(struct seq_file *m, struct uart_driver *drv, int i)
1819 {
1820 	struct uart_state *state = drv->state + i;
1821 	struct tty_port *port = &state->port;
1822 	enum uart_pm_state pm_state;
1823 	struct uart_port *uport;
1824 	char stat_buf[32];
1825 	unsigned int status;
1826 	int mmio;
1827 
1828 	mutex_lock(&port->mutex);
1829 	uport = uart_port_check(state);
1830 	if (!uport)
1831 		goto out;
1832 
1833 	mmio = uport->iotype >= UPIO_MEM;
1834 	seq_printf(m, "%d: uart:%s %s%08llX irq:%d",
1835 			uport->line, uart_type(uport),
1836 			mmio ? "mmio:0x" : "port:",
1837 			mmio ? (unsigned long long)uport->mapbase
1838 			     : (unsigned long long)uport->iobase,
1839 			uport->irq);
1840 
1841 	if (uport->type == PORT_UNKNOWN) {
1842 		seq_putc(m, '\n');
1843 		goto out;
1844 	}
1845 
1846 	if (capable(CAP_SYS_ADMIN)) {
1847 		pm_state = state->pm_state;
1848 		if (pm_state != UART_PM_STATE_ON)
1849 			uart_change_pm(state, UART_PM_STATE_ON);
1850 		spin_lock_irq(&uport->lock);
1851 		status = uport->ops->get_mctrl(uport);
1852 		spin_unlock_irq(&uport->lock);
1853 		if (pm_state != UART_PM_STATE_ON)
1854 			uart_change_pm(state, pm_state);
1855 
1856 		seq_printf(m, " tx:%d rx:%d",
1857 				uport->icount.tx, uport->icount.rx);
1858 		if (uport->icount.frame)
1859 			seq_printf(m, " fe:%d",	uport->icount.frame);
1860 		if (uport->icount.parity)
1861 			seq_printf(m, " pe:%d",	uport->icount.parity);
1862 		if (uport->icount.brk)
1863 			seq_printf(m, " brk:%d", uport->icount.brk);
1864 		if (uport->icount.overrun)
1865 			seq_printf(m, " oe:%d", uport->icount.overrun);
1866 		if (uport->icount.buf_overrun)
1867 			seq_printf(m, " bo:%d", uport->icount.buf_overrun);
1868 
1869 #define INFOBIT(bit, str) \
1870 	if (uport->mctrl & (bit)) \
1871 		strncat(stat_buf, (str), sizeof(stat_buf) - \
1872 			strlen(stat_buf) - 2)
1873 #define STATBIT(bit, str) \
1874 	if (status & (bit)) \
1875 		strncat(stat_buf, (str), sizeof(stat_buf) - \
1876 		       strlen(stat_buf) - 2)
1877 
1878 		stat_buf[0] = '\0';
1879 		stat_buf[1] = '\0';
1880 		INFOBIT(TIOCM_RTS, "|RTS");
1881 		STATBIT(TIOCM_CTS, "|CTS");
1882 		INFOBIT(TIOCM_DTR, "|DTR");
1883 		STATBIT(TIOCM_DSR, "|DSR");
1884 		STATBIT(TIOCM_CAR, "|CD");
1885 		STATBIT(TIOCM_RNG, "|RI");
1886 		if (stat_buf[0])
1887 			stat_buf[0] = ' ';
1888 
1889 		seq_puts(m, stat_buf);
1890 	}
1891 	seq_putc(m, '\n');
1892 #undef STATBIT
1893 #undef INFOBIT
1894 out:
1895 	mutex_unlock(&port->mutex);
1896 }
1897 
1898 static int uart_proc_show(struct seq_file *m, void *v)
1899 {
1900 	struct tty_driver *ttydrv = m->private;
1901 	struct uart_driver *drv = ttydrv->driver_state;
1902 	int i;
1903 
1904 	seq_printf(m, "serinfo:1.0 driver%s%s revision:%s\n", "", "", "");
1905 	for (i = 0; i < drv->nr; i++)
1906 		uart_line_info(m, drv, i);
1907 	return 0;
1908 }
1909 #endif
1910 
1911 #if defined(CONFIG_SERIAL_CORE_CONSOLE) || defined(CONFIG_CONSOLE_POLL)
1912 /**
1913  *	uart_console_write - write a console message to a serial port
1914  *	@port: the port to write the message
1915  *	@s: array of characters
1916  *	@count: number of characters in string to write
1917  *	@putchar: function to write character to port
1918  */
1919 void uart_console_write(struct uart_port *port, const char *s,
1920 			unsigned int count,
1921 			void (*putchar)(struct uart_port *, int))
1922 {
1923 	unsigned int i;
1924 
1925 	for (i = 0; i < count; i++, s++) {
1926 		if (*s == '\n')
1927 			putchar(port, '\r');
1928 		putchar(port, *s);
1929 	}
1930 }
1931 EXPORT_SYMBOL_GPL(uart_console_write);
1932 
1933 /*
1934  *	Check whether an invalid uart number has been specified, and
1935  *	if so, search for the first available port that does have
1936  *	console support.
1937  */
1938 struct uart_port * __init
1939 uart_get_console(struct uart_port *ports, int nr, struct console *co)
1940 {
1941 	int idx = co->index;
1942 
1943 	if (idx < 0 || idx >= nr || (ports[idx].iobase == 0 &&
1944 				     ports[idx].membase == NULL))
1945 		for (idx = 0; idx < nr; idx++)
1946 			if (ports[idx].iobase != 0 ||
1947 			    ports[idx].membase != NULL)
1948 				break;
1949 
1950 	co->index = idx;
1951 
1952 	return ports + idx;
1953 }
1954 
1955 /**
1956  *	uart_parse_earlycon - Parse earlycon options
1957  *	@p:	  ptr to 2nd field (ie., just beyond '<name>,')
1958  *	@iotype:  ptr for decoded iotype (out)
1959  *	@addr:    ptr for decoded mapbase/iobase (out)
1960  *	@options: ptr for <options> field; NULL if not present (out)
1961  *
1962  *	Decodes earlycon kernel command line parameters of the form
1963  *	   earlycon=<name>,io|mmio|mmio16|mmio32|mmio32be|mmio32native,<addr>,<options>
1964  *	   console=<name>,io|mmio|mmio16|mmio32|mmio32be|mmio32native,<addr>,<options>
1965  *
1966  *	The optional form
1967  *
1968  *	   earlycon=<name>,0x<addr>,<options>
1969  *	   console=<name>,0x<addr>,<options>
1970  *
1971  *	is also accepted; the returned @iotype will be UPIO_MEM.
1972  *
1973  *	Returns 0 on success or -EINVAL on failure
1974  */
1975 int uart_parse_earlycon(char *p, unsigned char *iotype, resource_size_t *addr,
1976 			char **options)
1977 {
1978 	if (strncmp(p, "mmio,", 5) == 0) {
1979 		*iotype = UPIO_MEM;
1980 		p += 5;
1981 	} else if (strncmp(p, "mmio16,", 7) == 0) {
1982 		*iotype = UPIO_MEM16;
1983 		p += 7;
1984 	} else if (strncmp(p, "mmio32,", 7) == 0) {
1985 		*iotype = UPIO_MEM32;
1986 		p += 7;
1987 	} else if (strncmp(p, "mmio32be,", 9) == 0) {
1988 		*iotype = UPIO_MEM32BE;
1989 		p += 9;
1990 	} else if (strncmp(p, "mmio32native,", 13) == 0) {
1991 		*iotype = IS_ENABLED(CONFIG_CPU_BIG_ENDIAN) ?
1992 			UPIO_MEM32BE : UPIO_MEM32;
1993 		p += 13;
1994 	} else if (strncmp(p, "io,", 3) == 0) {
1995 		*iotype = UPIO_PORT;
1996 		p += 3;
1997 	} else if (strncmp(p, "0x", 2) == 0) {
1998 		*iotype = UPIO_MEM;
1999 	} else {
2000 		return -EINVAL;
2001 	}
2002 
2003 	/*
2004 	 * Before you replace it with kstrtoull(), think about options separator
2005 	 * (',') it will not tolerate
2006 	 */
2007 	*addr = simple_strtoull(p, NULL, 0);
2008 	p = strchr(p, ',');
2009 	if (p)
2010 		p++;
2011 
2012 	*options = p;
2013 	return 0;
2014 }
2015 EXPORT_SYMBOL_GPL(uart_parse_earlycon);
2016 
2017 /**
2018  *	uart_parse_options - Parse serial port baud/parity/bits/flow control.
2019  *	@options: pointer to option string
2020  *	@baud: pointer to an 'int' variable for the baud rate.
2021  *	@parity: pointer to an 'int' variable for the parity.
2022  *	@bits: pointer to an 'int' variable for the number of data bits.
2023  *	@flow: pointer to an 'int' variable for the flow control character.
2024  *
2025  *	uart_parse_options decodes a string containing the serial console
2026  *	options.  The format of the string is <baud><parity><bits><flow>,
2027  *	eg: 115200n8r
2028  */
2029 void
2030 uart_parse_options(const char *options, int *baud, int *parity,
2031 		   int *bits, int *flow)
2032 {
2033 	const char *s = options;
2034 
2035 	*baud = simple_strtoul(s, NULL, 10);
2036 	while (*s >= '0' && *s <= '9')
2037 		s++;
2038 	if (*s)
2039 		*parity = *s++;
2040 	if (*s)
2041 		*bits = *s++ - '0';
2042 	if (*s)
2043 		*flow = *s;
2044 }
2045 EXPORT_SYMBOL_GPL(uart_parse_options);
2046 
2047 /**
2048  *	uart_set_options - setup the serial console parameters
2049  *	@port: pointer to the serial ports uart_port structure
2050  *	@co: console pointer
2051  *	@baud: baud rate
2052  *	@parity: parity character - 'n' (none), 'o' (odd), 'e' (even)
2053  *	@bits: number of data bits
2054  *	@flow: flow control character - 'r' (rts)
2055  */
2056 int
2057 uart_set_options(struct uart_port *port, struct console *co,
2058 		 int baud, int parity, int bits, int flow)
2059 {
2060 	struct ktermios termios;
2061 	static struct ktermios dummy;
2062 
2063 	/*
2064 	 * Ensure that the serial console lock is initialised
2065 	 * early.
2066 	 * If this port is a console, then the spinlock is already
2067 	 * initialised.
2068 	 */
2069 	if (!(uart_console(port) && (port->cons->flags & CON_ENABLED))) {
2070 		spin_lock_init(&port->lock);
2071 		lockdep_set_class(&port->lock, &port_lock_key);
2072 	}
2073 
2074 	memset(&termios, 0, sizeof(struct ktermios));
2075 
2076 	termios.c_cflag |= CREAD | HUPCL | CLOCAL;
2077 	tty_termios_encode_baud_rate(&termios, baud, baud);
2078 
2079 	if (bits == 7)
2080 		termios.c_cflag |= CS7;
2081 	else
2082 		termios.c_cflag |= CS8;
2083 
2084 	switch (parity) {
2085 	case 'o': case 'O':
2086 		termios.c_cflag |= PARODD;
2087 		/*fall through*/
2088 	case 'e': case 'E':
2089 		termios.c_cflag |= PARENB;
2090 		break;
2091 	}
2092 
2093 	if (flow == 'r')
2094 		termios.c_cflag |= CRTSCTS;
2095 
2096 	/*
2097 	 * some uarts on other side don't support no flow control.
2098 	 * So we set * DTR in host uart to make them happy
2099 	 */
2100 	port->mctrl |= TIOCM_DTR;
2101 
2102 	port->ops->set_termios(port, &termios, &dummy);
2103 	/*
2104 	 * Allow the setting of the UART parameters with a NULL console
2105 	 * too:
2106 	 */
2107 	if (co)
2108 		co->cflag = termios.c_cflag;
2109 
2110 	return 0;
2111 }
2112 EXPORT_SYMBOL_GPL(uart_set_options);
2113 #endif /* CONFIG_SERIAL_CORE_CONSOLE */
2114 
2115 /**
2116  * uart_change_pm - set power state of the port
2117  *
2118  * @state: port descriptor
2119  * @pm_state: new state
2120  *
2121  * Locking: port->mutex has to be held
2122  */
2123 static void uart_change_pm(struct uart_state *state,
2124 			   enum uart_pm_state pm_state)
2125 {
2126 	struct uart_port *port = uart_port_check(state);
2127 
2128 	if (state->pm_state != pm_state) {
2129 		if (port && port->ops->pm)
2130 			port->ops->pm(port, pm_state, state->pm_state);
2131 		state->pm_state = pm_state;
2132 	}
2133 }
2134 
2135 struct uart_match {
2136 	struct uart_port *port;
2137 	struct uart_driver *driver;
2138 };
2139 
2140 static int serial_match_port(struct device *dev, void *data)
2141 {
2142 	struct uart_match *match = data;
2143 	struct tty_driver *tty_drv = match->driver->tty_driver;
2144 	dev_t devt = MKDEV(tty_drv->major, tty_drv->minor_start) +
2145 		match->port->line;
2146 
2147 	return dev->devt == devt; /* Actually, only one tty per port */
2148 }
2149 
2150 int uart_suspend_port(struct uart_driver *drv, struct uart_port *uport)
2151 {
2152 	struct uart_state *state = drv->state + uport->line;
2153 	struct tty_port *port = &state->port;
2154 	struct device *tty_dev;
2155 	struct uart_match match = {uport, drv};
2156 
2157 	mutex_lock(&port->mutex);
2158 
2159 	tty_dev = device_find_child(uport->dev, &match, serial_match_port);
2160 	if (tty_dev && device_may_wakeup(tty_dev)) {
2161 		enable_irq_wake(uport->irq);
2162 		put_device(tty_dev);
2163 		mutex_unlock(&port->mutex);
2164 		return 0;
2165 	}
2166 	put_device(tty_dev);
2167 
2168 	/* Nothing to do if the console is not suspending */
2169 	if (!console_suspend_enabled && uart_console(uport))
2170 		goto unlock;
2171 
2172 	uport->suspended = 1;
2173 
2174 	if (tty_port_initialized(port)) {
2175 		const struct uart_ops *ops = uport->ops;
2176 		int tries;
2177 
2178 		tty_port_set_suspended(port, 1);
2179 		tty_port_set_initialized(port, 0);
2180 
2181 		spin_lock_irq(&uport->lock);
2182 		ops->stop_tx(uport);
2183 		ops->set_mctrl(uport, 0);
2184 		ops->stop_rx(uport);
2185 		spin_unlock_irq(&uport->lock);
2186 
2187 		/*
2188 		 * Wait for the transmitter to empty.
2189 		 */
2190 		for (tries = 3; !ops->tx_empty(uport) && tries; tries--)
2191 			msleep(10);
2192 		if (!tries)
2193 			dev_err(uport->dev, "%s: Unable to drain transmitter\n",
2194 				uport->name);
2195 
2196 		ops->shutdown(uport);
2197 	}
2198 
2199 	/*
2200 	 * Disable the console device before suspending.
2201 	 */
2202 	if (uart_console(uport))
2203 		console_stop(uport->cons);
2204 
2205 	uart_change_pm(state, UART_PM_STATE_OFF);
2206 unlock:
2207 	mutex_unlock(&port->mutex);
2208 
2209 	return 0;
2210 }
2211 
2212 int uart_resume_port(struct uart_driver *drv, struct uart_port *uport)
2213 {
2214 	struct uart_state *state = drv->state + uport->line;
2215 	struct tty_port *port = &state->port;
2216 	struct device *tty_dev;
2217 	struct uart_match match = {uport, drv};
2218 	struct ktermios termios;
2219 
2220 	mutex_lock(&port->mutex);
2221 
2222 	tty_dev = device_find_child(uport->dev, &match, serial_match_port);
2223 	if (!uport->suspended && device_may_wakeup(tty_dev)) {
2224 		if (irqd_is_wakeup_set(irq_get_irq_data((uport->irq))))
2225 			disable_irq_wake(uport->irq);
2226 		put_device(tty_dev);
2227 		mutex_unlock(&port->mutex);
2228 		return 0;
2229 	}
2230 	put_device(tty_dev);
2231 	uport->suspended = 0;
2232 
2233 	/*
2234 	 * Re-enable the console device after suspending.
2235 	 */
2236 	if (uart_console(uport)) {
2237 		/*
2238 		 * First try to use the console cflag setting.
2239 		 */
2240 		memset(&termios, 0, sizeof(struct ktermios));
2241 		termios.c_cflag = uport->cons->cflag;
2242 
2243 		/*
2244 		 * If that's unset, use the tty termios setting.
2245 		 */
2246 		if (port->tty && termios.c_cflag == 0)
2247 			termios = port->tty->termios;
2248 
2249 		if (console_suspend_enabled)
2250 			uart_change_pm(state, UART_PM_STATE_ON);
2251 		uport->ops->set_termios(uport, &termios, NULL);
2252 		if (console_suspend_enabled)
2253 			console_start(uport->cons);
2254 	}
2255 
2256 	if (tty_port_suspended(port)) {
2257 		const struct uart_ops *ops = uport->ops;
2258 		int ret;
2259 
2260 		uart_change_pm(state, UART_PM_STATE_ON);
2261 		spin_lock_irq(&uport->lock);
2262 		ops->set_mctrl(uport, 0);
2263 		spin_unlock_irq(&uport->lock);
2264 		if (console_suspend_enabled || !uart_console(uport)) {
2265 			/* Protected by port mutex for now */
2266 			struct tty_struct *tty = port->tty;
2267 			ret = ops->startup(uport);
2268 			if (ret == 0) {
2269 				if (tty)
2270 					uart_change_speed(tty, state, NULL);
2271 				spin_lock_irq(&uport->lock);
2272 				ops->set_mctrl(uport, uport->mctrl);
2273 				ops->start_tx(uport);
2274 				spin_unlock_irq(&uport->lock);
2275 				tty_port_set_initialized(port, 1);
2276 			} else {
2277 				/*
2278 				 * Failed to resume - maybe hardware went away?
2279 				 * Clear the "initialized" flag so we won't try
2280 				 * to call the low level drivers shutdown method.
2281 				 */
2282 				uart_shutdown(tty, state);
2283 			}
2284 		}
2285 
2286 		tty_port_set_suspended(port, 0);
2287 	}
2288 
2289 	mutex_unlock(&port->mutex);
2290 
2291 	return 0;
2292 }
2293 
2294 static inline void
2295 uart_report_port(struct uart_driver *drv, struct uart_port *port)
2296 {
2297 	char address[64];
2298 
2299 	switch (port->iotype) {
2300 	case UPIO_PORT:
2301 		snprintf(address, sizeof(address), "I/O 0x%lx", port->iobase);
2302 		break;
2303 	case UPIO_HUB6:
2304 		snprintf(address, sizeof(address),
2305 			 "I/O 0x%lx offset 0x%x", port->iobase, port->hub6);
2306 		break;
2307 	case UPIO_MEM:
2308 	case UPIO_MEM16:
2309 	case UPIO_MEM32:
2310 	case UPIO_MEM32BE:
2311 	case UPIO_AU:
2312 	case UPIO_TSI:
2313 		snprintf(address, sizeof(address),
2314 			 "MMIO 0x%llx", (unsigned long long)port->mapbase);
2315 		break;
2316 	default:
2317 		strlcpy(address, "*unknown*", sizeof(address));
2318 		break;
2319 	}
2320 
2321 	pr_info("%s%s%s at %s (irq = %d, base_baud = %d) is a %s\n",
2322 	       port->dev ? dev_name(port->dev) : "",
2323 	       port->dev ? ": " : "",
2324 	       port->name,
2325 	       address, port->irq, port->uartclk / 16, uart_type(port));
2326 }
2327 
2328 static void
2329 uart_configure_port(struct uart_driver *drv, struct uart_state *state,
2330 		    struct uart_port *port)
2331 {
2332 	unsigned int flags;
2333 
2334 	/*
2335 	 * If there isn't a port here, don't do anything further.
2336 	 */
2337 	if (!port->iobase && !port->mapbase && !port->membase)
2338 		return;
2339 
2340 	/*
2341 	 * Now do the auto configuration stuff.  Note that config_port
2342 	 * is expected to claim the resources and map the port for us.
2343 	 */
2344 	flags = 0;
2345 	if (port->flags & UPF_AUTO_IRQ)
2346 		flags |= UART_CONFIG_IRQ;
2347 	if (port->flags & UPF_BOOT_AUTOCONF) {
2348 		if (!(port->flags & UPF_FIXED_TYPE)) {
2349 			port->type = PORT_UNKNOWN;
2350 			flags |= UART_CONFIG_TYPE;
2351 		}
2352 		port->ops->config_port(port, flags);
2353 	}
2354 
2355 	if (port->type != PORT_UNKNOWN) {
2356 		unsigned long flags;
2357 
2358 		uart_report_port(drv, port);
2359 
2360 		/* Power up port for set_mctrl() */
2361 		uart_change_pm(state, UART_PM_STATE_ON);
2362 
2363 		/*
2364 		 * Ensure that the modem control lines are de-activated.
2365 		 * keep the DTR setting that is set in uart_set_options()
2366 		 * We probably don't need a spinlock around this, but
2367 		 */
2368 		spin_lock_irqsave(&port->lock, flags);
2369 		port->ops->set_mctrl(port, port->mctrl & TIOCM_DTR);
2370 		spin_unlock_irqrestore(&port->lock, flags);
2371 
2372 		/*
2373 		 * If this driver supports console, and it hasn't been
2374 		 * successfully registered yet, try to re-register it.
2375 		 * It may be that the port was not available.
2376 		 */
2377 		if (port->cons && !(port->cons->flags & CON_ENABLED))
2378 			register_console(port->cons);
2379 
2380 		/*
2381 		 * Power down all ports by default, except the
2382 		 * console if we have one.
2383 		 */
2384 		if (!uart_console(port))
2385 			uart_change_pm(state, UART_PM_STATE_OFF);
2386 	}
2387 }
2388 
2389 #ifdef CONFIG_CONSOLE_POLL
2390 
2391 static int uart_poll_init(struct tty_driver *driver, int line, char *options)
2392 {
2393 	struct uart_driver *drv = driver->driver_state;
2394 	struct uart_state *state = drv->state + line;
2395 	struct tty_port *tport;
2396 	struct uart_port *port;
2397 	int baud = 9600;
2398 	int bits = 8;
2399 	int parity = 'n';
2400 	int flow = 'n';
2401 	int ret = 0;
2402 
2403 	tport = &state->port;
2404 	mutex_lock(&tport->mutex);
2405 
2406 	port = uart_port_check(state);
2407 	if (!port || !(port->ops->poll_get_char && port->ops->poll_put_char)) {
2408 		ret = -1;
2409 		goto out;
2410 	}
2411 
2412 	if (port->ops->poll_init) {
2413 		/*
2414 		 * We don't set initialized as we only initialized the hw,
2415 		 * e.g. state->xmit is still uninitialized.
2416 		 */
2417 		if (!tty_port_initialized(tport))
2418 			ret = port->ops->poll_init(port);
2419 	}
2420 
2421 	if (!ret && options) {
2422 		uart_parse_options(options, &baud, &parity, &bits, &flow);
2423 		ret = uart_set_options(port, NULL, baud, parity, bits, flow);
2424 	}
2425 out:
2426 	mutex_unlock(&tport->mutex);
2427 	return ret;
2428 }
2429 
2430 static int uart_poll_get_char(struct tty_driver *driver, int line)
2431 {
2432 	struct uart_driver *drv = driver->driver_state;
2433 	struct uart_state *state = drv->state + line;
2434 	struct uart_port *port;
2435 	int ret = -1;
2436 
2437 	port = uart_port_ref(state);
2438 	if (port) {
2439 		ret = port->ops->poll_get_char(port);
2440 		uart_port_deref(port);
2441 	}
2442 
2443 	return ret;
2444 }
2445 
2446 static void uart_poll_put_char(struct tty_driver *driver, int line, char ch)
2447 {
2448 	struct uart_driver *drv = driver->driver_state;
2449 	struct uart_state *state = drv->state + line;
2450 	struct uart_port *port;
2451 
2452 	port = uart_port_ref(state);
2453 	if (!port)
2454 		return;
2455 
2456 	if (ch == '\n')
2457 		port->ops->poll_put_char(port, '\r');
2458 	port->ops->poll_put_char(port, ch);
2459 	uart_port_deref(port);
2460 }
2461 #endif
2462 
2463 static const struct tty_operations uart_ops = {
2464 	.install	= uart_install,
2465 	.open		= uart_open,
2466 	.close		= uart_close,
2467 	.write		= uart_write,
2468 	.put_char	= uart_put_char,
2469 	.flush_chars	= uart_flush_chars,
2470 	.write_room	= uart_write_room,
2471 	.chars_in_buffer= uart_chars_in_buffer,
2472 	.flush_buffer	= uart_flush_buffer,
2473 	.ioctl		= uart_ioctl,
2474 	.throttle	= uart_throttle,
2475 	.unthrottle	= uart_unthrottle,
2476 	.send_xchar	= uart_send_xchar,
2477 	.set_termios	= uart_set_termios,
2478 	.set_ldisc	= uart_set_ldisc,
2479 	.stop		= uart_stop,
2480 	.start		= uart_start,
2481 	.hangup		= uart_hangup,
2482 	.break_ctl	= uart_break_ctl,
2483 	.wait_until_sent= uart_wait_until_sent,
2484 #ifdef CONFIG_PROC_FS
2485 	.proc_show	= uart_proc_show,
2486 #endif
2487 	.tiocmget	= uart_tiocmget,
2488 	.tiocmset	= uart_tiocmset,
2489 	.set_serial	= uart_set_info_user,
2490 	.get_serial	= uart_get_info_user,
2491 	.get_icount	= uart_get_icount,
2492 #ifdef CONFIG_CONSOLE_POLL
2493 	.poll_init	= uart_poll_init,
2494 	.poll_get_char	= uart_poll_get_char,
2495 	.poll_put_char	= uart_poll_put_char,
2496 #endif
2497 };
2498 
2499 static const struct tty_port_operations uart_port_ops = {
2500 	.carrier_raised = uart_carrier_raised,
2501 	.dtr_rts	= uart_dtr_rts,
2502 	.activate	= uart_port_activate,
2503 	.shutdown	= uart_tty_port_shutdown,
2504 };
2505 
2506 /**
2507  *	uart_register_driver - register a driver with the uart core layer
2508  *	@drv: low level driver structure
2509  *
2510  *	Register a uart driver with the core driver.  We in turn register
2511  *	with the tty layer, and initialise the core driver per-port state.
2512  *
2513  *	We have a proc file in /proc/tty/driver which is named after the
2514  *	normal driver.
2515  *
2516  *	drv->port should be NULL, and the per-port structures should be
2517  *	registered using uart_add_one_port after this call has succeeded.
2518  */
2519 int uart_register_driver(struct uart_driver *drv)
2520 {
2521 	struct tty_driver *normal;
2522 	int i, retval = -ENOMEM;
2523 
2524 	BUG_ON(drv->state);
2525 
2526 	/*
2527 	 * Maybe we should be using a slab cache for this, especially if
2528 	 * we have a large number of ports to handle.
2529 	 */
2530 	drv->state = kcalloc(drv->nr, sizeof(struct uart_state), GFP_KERNEL);
2531 	if (!drv->state)
2532 		goto out;
2533 
2534 	normal = alloc_tty_driver(drv->nr);
2535 	if (!normal)
2536 		goto out_kfree;
2537 
2538 	drv->tty_driver = normal;
2539 
2540 	normal->driver_name	= drv->driver_name;
2541 	normal->name		= drv->dev_name;
2542 	normal->major		= drv->major;
2543 	normal->minor_start	= drv->minor;
2544 	normal->type		= TTY_DRIVER_TYPE_SERIAL;
2545 	normal->subtype		= SERIAL_TYPE_NORMAL;
2546 	normal->init_termios	= tty_std_termios;
2547 	normal->init_termios.c_cflag = B9600 | CS8 | CREAD | HUPCL | CLOCAL;
2548 	normal->init_termios.c_ispeed = normal->init_termios.c_ospeed = 9600;
2549 	normal->flags		= TTY_DRIVER_REAL_RAW | TTY_DRIVER_DYNAMIC_DEV;
2550 	normal->driver_state    = drv;
2551 	tty_set_operations(normal, &uart_ops);
2552 
2553 	/*
2554 	 * Initialise the UART state(s).
2555 	 */
2556 	for (i = 0; i < drv->nr; i++) {
2557 		struct uart_state *state = drv->state + i;
2558 		struct tty_port *port = &state->port;
2559 
2560 		tty_port_init(port);
2561 		port->ops = &uart_port_ops;
2562 	}
2563 
2564 	retval = tty_register_driver(normal);
2565 	if (retval >= 0)
2566 		return retval;
2567 
2568 	for (i = 0; i < drv->nr; i++)
2569 		tty_port_destroy(&drv->state[i].port);
2570 	put_tty_driver(normal);
2571 out_kfree:
2572 	kfree(drv->state);
2573 out:
2574 	return retval;
2575 }
2576 
2577 /**
2578  *	uart_unregister_driver - remove a driver from the uart core layer
2579  *	@drv: low level driver structure
2580  *
2581  *	Remove all references to a driver from the core driver.  The low
2582  *	level driver must have removed all its ports via the
2583  *	uart_remove_one_port() if it registered them with uart_add_one_port().
2584  *	(ie, drv->port == NULL)
2585  */
2586 void uart_unregister_driver(struct uart_driver *drv)
2587 {
2588 	struct tty_driver *p = drv->tty_driver;
2589 	unsigned int i;
2590 
2591 	tty_unregister_driver(p);
2592 	put_tty_driver(p);
2593 	for (i = 0; i < drv->nr; i++)
2594 		tty_port_destroy(&drv->state[i].port);
2595 	kfree(drv->state);
2596 	drv->state = NULL;
2597 	drv->tty_driver = NULL;
2598 }
2599 
2600 struct tty_driver *uart_console_device(struct console *co, int *index)
2601 {
2602 	struct uart_driver *p = co->data;
2603 	*index = co->index;
2604 	return p->tty_driver;
2605 }
2606 
2607 static ssize_t uart_get_attr_uartclk(struct device *dev,
2608 	struct device_attribute *attr, char *buf)
2609 {
2610 	struct serial_struct tmp;
2611 	struct tty_port *port = dev_get_drvdata(dev);
2612 
2613 	uart_get_info(port, &tmp);
2614 	return snprintf(buf, PAGE_SIZE, "%d\n", tmp.baud_base * 16);
2615 }
2616 
2617 static ssize_t uart_get_attr_type(struct device *dev,
2618 	struct device_attribute *attr, char *buf)
2619 {
2620 	struct serial_struct tmp;
2621 	struct tty_port *port = dev_get_drvdata(dev);
2622 
2623 	uart_get_info(port, &tmp);
2624 	return snprintf(buf, PAGE_SIZE, "%d\n", tmp.type);
2625 }
2626 static ssize_t uart_get_attr_line(struct device *dev,
2627 	struct device_attribute *attr, char *buf)
2628 {
2629 	struct serial_struct tmp;
2630 	struct tty_port *port = dev_get_drvdata(dev);
2631 
2632 	uart_get_info(port, &tmp);
2633 	return snprintf(buf, PAGE_SIZE, "%d\n", tmp.line);
2634 }
2635 
2636 static ssize_t uart_get_attr_port(struct device *dev,
2637 	struct device_attribute *attr, char *buf)
2638 {
2639 	struct serial_struct tmp;
2640 	struct tty_port *port = dev_get_drvdata(dev);
2641 	unsigned long ioaddr;
2642 
2643 	uart_get_info(port, &tmp);
2644 	ioaddr = tmp.port;
2645 	if (HIGH_BITS_OFFSET)
2646 		ioaddr |= (unsigned long)tmp.port_high << HIGH_BITS_OFFSET;
2647 	return snprintf(buf, PAGE_SIZE, "0x%lX\n", ioaddr);
2648 }
2649 
2650 static ssize_t uart_get_attr_irq(struct device *dev,
2651 	struct device_attribute *attr, char *buf)
2652 {
2653 	struct serial_struct tmp;
2654 	struct tty_port *port = dev_get_drvdata(dev);
2655 
2656 	uart_get_info(port, &tmp);
2657 	return snprintf(buf, PAGE_SIZE, "%d\n", tmp.irq);
2658 }
2659 
2660 static ssize_t uart_get_attr_flags(struct device *dev,
2661 	struct device_attribute *attr, char *buf)
2662 {
2663 	struct serial_struct tmp;
2664 	struct tty_port *port = dev_get_drvdata(dev);
2665 
2666 	uart_get_info(port, &tmp);
2667 	return snprintf(buf, PAGE_SIZE, "0x%X\n", tmp.flags);
2668 }
2669 
2670 static ssize_t uart_get_attr_xmit_fifo_size(struct device *dev,
2671 	struct device_attribute *attr, char *buf)
2672 {
2673 	struct serial_struct tmp;
2674 	struct tty_port *port = dev_get_drvdata(dev);
2675 
2676 	uart_get_info(port, &tmp);
2677 	return snprintf(buf, PAGE_SIZE, "%d\n", tmp.xmit_fifo_size);
2678 }
2679 
2680 
2681 static ssize_t uart_get_attr_close_delay(struct device *dev,
2682 	struct device_attribute *attr, char *buf)
2683 {
2684 	struct serial_struct tmp;
2685 	struct tty_port *port = dev_get_drvdata(dev);
2686 
2687 	uart_get_info(port, &tmp);
2688 	return snprintf(buf, PAGE_SIZE, "%d\n", tmp.close_delay);
2689 }
2690 
2691 
2692 static ssize_t uart_get_attr_closing_wait(struct device *dev,
2693 	struct device_attribute *attr, char *buf)
2694 {
2695 	struct serial_struct tmp;
2696 	struct tty_port *port = dev_get_drvdata(dev);
2697 
2698 	uart_get_info(port, &tmp);
2699 	return snprintf(buf, PAGE_SIZE, "%d\n", tmp.closing_wait);
2700 }
2701 
2702 static ssize_t uart_get_attr_custom_divisor(struct device *dev,
2703 	struct device_attribute *attr, char *buf)
2704 {
2705 	struct serial_struct tmp;
2706 	struct tty_port *port = dev_get_drvdata(dev);
2707 
2708 	uart_get_info(port, &tmp);
2709 	return snprintf(buf, PAGE_SIZE, "%d\n", tmp.custom_divisor);
2710 }
2711 
2712 static ssize_t uart_get_attr_io_type(struct device *dev,
2713 	struct device_attribute *attr, char *buf)
2714 {
2715 	struct serial_struct tmp;
2716 	struct tty_port *port = dev_get_drvdata(dev);
2717 
2718 	uart_get_info(port, &tmp);
2719 	return snprintf(buf, PAGE_SIZE, "%d\n", tmp.io_type);
2720 }
2721 
2722 static ssize_t uart_get_attr_iomem_base(struct device *dev,
2723 	struct device_attribute *attr, char *buf)
2724 {
2725 	struct serial_struct tmp;
2726 	struct tty_port *port = dev_get_drvdata(dev);
2727 
2728 	uart_get_info(port, &tmp);
2729 	return snprintf(buf, PAGE_SIZE, "0x%lX\n", (unsigned long)tmp.iomem_base);
2730 }
2731 
2732 static ssize_t uart_get_attr_iomem_reg_shift(struct device *dev,
2733 	struct device_attribute *attr, char *buf)
2734 {
2735 	struct serial_struct tmp;
2736 	struct tty_port *port = dev_get_drvdata(dev);
2737 
2738 	uart_get_info(port, &tmp);
2739 	return snprintf(buf, PAGE_SIZE, "%d\n", tmp.iomem_reg_shift);
2740 }
2741 
2742 static DEVICE_ATTR(type, S_IRUSR | S_IRGRP, uart_get_attr_type, NULL);
2743 static DEVICE_ATTR(line, S_IRUSR | S_IRGRP, uart_get_attr_line, NULL);
2744 static DEVICE_ATTR(port, S_IRUSR | S_IRGRP, uart_get_attr_port, NULL);
2745 static DEVICE_ATTR(irq, S_IRUSR | S_IRGRP, uart_get_attr_irq, NULL);
2746 static DEVICE_ATTR(flags, S_IRUSR | S_IRGRP, uart_get_attr_flags, NULL);
2747 static DEVICE_ATTR(xmit_fifo_size, S_IRUSR | S_IRGRP, uart_get_attr_xmit_fifo_size, NULL);
2748 static DEVICE_ATTR(uartclk, S_IRUSR | S_IRGRP, uart_get_attr_uartclk, NULL);
2749 static DEVICE_ATTR(close_delay, S_IRUSR | S_IRGRP, uart_get_attr_close_delay, NULL);
2750 static DEVICE_ATTR(closing_wait, S_IRUSR | S_IRGRP, uart_get_attr_closing_wait, NULL);
2751 static DEVICE_ATTR(custom_divisor, S_IRUSR | S_IRGRP, uart_get_attr_custom_divisor, NULL);
2752 static DEVICE_ATTR(io_type, S_IRUSR | S_IRGRP, uart_get_attr_io_type, NULL);
2753 static DEVICE_ATTR(iomem_base, S_IRUSR | S_IRGRP, uart_get_attr_iomem_base, NULL);
2754 static DEVICE_ATTR(iomem_reg_shift, S_IRUSR | S_IRGRP, uart_get_attr_iomem_reg_shift, NULL);
2755 
2756 static struct attribute *tty_dev_attrs[] = {
2757 	&dev_attr_type.attr,
2758 	&dev_attr_line.attr,
2759 	&dev_attr_port.attr,
2760 	&dev_attr_irq.attr,
2761 	&dev_attr_flags.attr,
2762 	&dev_attr_xmit_fifo_size.attr,
2763 	&dev_attr_uartclk.attr,
2764 	&dev_attr_close_delay.attr,
2765 	&dev_attr_closing_wait.attr,
2766 	&dev_attr_custom_divisor.attr,
2767 	&dev_attr_io_type.attr,
2768 	&dev_attr_iomem_base.attr,
2769 	&dev_attr_iomem_reg_shift.attr,
2770 	NULL,
2771 	};
2772 
2773 static const struct attribute_group tty_dev_attr_group = {
2774 	.attrs = tty_dev_attrs,
2775 	};
2776 
2777 /**
2778  *	uart_add_one_port - attach a driver-defined port structure
2779  *	@drv: pointer to the uart low level driver structure for this port
2780  *	@uport: uart port structure to use for this port.
2781  *
2782  *	This allows the driver to register its own uart_port structure
2783  *	with the core driver.  The main purpose is to allow the low
2784  *	level uart drivers to expand uart_port, rather than having yet
2785  *	more levels of structures.
2786  */
2787 int uart_add_one_port(struct uart_driver *drv, struct uart_port *uport)
2788 {
2789 	struct uart_state *state;
2790 	struct tty_port *port;
2791 	int ret = 0;
2792 	struct device *tty_dev;
2793 	int num_groups;
2794 
2795 	BUG_ON(in_interrupt());
2796 
2797 	if (uport->line >= drv->nr)
2798 		return -EINVAL;
2799 
2800 	state = drv->state + uport->line;
2801 	port = &state->port;
2802 
2803 	mutex_lock(&port_mutex);
2804 	mutex_lock(&port->mutex);
2805 	if (state->uart_port) {
2806 		ret = -EINVAL;
2807 		goto out;
2808 	}
2809 
2810 	/* Link the port to the driver state table and vice versa */
2811 	atomic_set(&state->refcount, 1);
2812 	init_waitqueue_head(&state->remove_wait);
2813 	state->uart_port = uport;
2814 	uport->state = state;
2815 
2816 	state->pm_state = UART_PM_STATE_UNDEFINED;
2817 	uport->cons = drv->cons;
2818 	uport->minor = drv->tty_driver->minor_start + uport->line;
2819 	uport->name = kasprintf(GFP_KERNEL, "%s%d", drv->dev_name,
2820 				drv->tty_driver->name_base + uport->line);
2821 	if (!uport->name) {
2822 		ret = -ENOMEM;
2823 		goto out;
2824 	}
2825 
2826 	/*
2827 	 * If this port is a console, then the spinlock is already
2828 	 * initialised.
2829 	 */
2830 	if (!(uart_console(uport) && (uport->cons->flags & CON_ENABLED))) {
2831 		spin_lock_init(&uport->lock);
2832 		lockdep_set_class(&uport->lock, &port_lock_key);
2833 	}
2834 	if (uport->cons && uport->dev)
2835 		of_console_check(uport->dev->of_node, uport->cons->name, uport->line);
2836 
2837 	tty_port_link_device(port, drv->tty_driver, uport->line);
2838 	uart_configure_port(drv, state, uport);
2839 
2840 	port->console = uart_console(uport);
2841 
2842 	num_groups = 2;
2843 	if (uport->attr_group)
2844 		num_groups++;
2845 
2846 	uport->tty_groups = kcalloc(num_groups, sizeof(*uport->tty_groups),
2847 				    GFP_KERNEL);
2848 	if (!uport->tty_groups) {
2849 		ret = -ENOMEM;
2850 		goto out;
2851 	}
2852 	uport->tty_groups[0] = &tty_dev_attr_group;
2853 	if (uport->attr_group)
2854 		uport->tty_groups[1] = uport->attr_group;
2855 
2856 	/*
2857 	 * Register the port whether it's detected or not.  This allows
2858 	 * setserial to be used to alter this port's parameters.
2859 	 */
2860 	tty_dev = tty_port_register_device_attr_serdev(port, drv->tty_driver,
2861 			uport->line, uport->dev, port, uport->tty_groups);
2862 	if (!IS_ERR(tty_dev)) {
2863 		device_set_wakeup_capable(tty_dev, 1);
2864 	} else {
2865 		dev_err(uport->dev, "Cannot register tty device on line %d\n",
2866 		       uport->line);
2867 	}
2868 
2869 	/*
2870 	 * Ensure UPF_DEAD is not set.
2871 	 */
2872 	uport->flags &= ~UPF_DEAD;
2873 
2874  out:
2875 	mutex_unlock(&port->mutex);
2876 	mutex_unlock(&port_mutex);
2877 
2878 	return ret;
2879 }
2880 
2881 /**
2882  *	uart_remove_one_port - detach a driver defined port structure
2883  *	@drv: pointer to the uart low level driver structure for this port
2884  *	@uport: uart port structure for this port
2885  *
2886  *	This unhooks (and hangs up) the specified port structure from the
2887  *	core driver.  No further calls will be made to the low-level code
2888  *	for this port.
2889  */
2890 int uart_remove_one_port(struct uart_driver *drv, struct uart_port *uport)
2891 {
2892 	struct uart_state *state = drv->state + uport->line;
2893 	struct tty_port *port = &state->port;
2894 	struct uart_port *uart_port;
2895 	struct tty_struct *tty;
2896 	int ret = 0;
2897 
2898 	BUG_ON(in_interrupt());
2899 
2900 	mutex_lock(&port_mutex);
2901 
2902 	/*
2903 	 * Mark the port "dead" - this prevents any opens from
2904 	 * succeeding while we shut down the port.
2905 	 */
2906 	mutex_lock(&port->mutex);
2907 	uart_port = uart_port_check(state);
2908 	if (uart_port != uport)
2909 		dev_alert(uport->dev, "Removing wrong port: %p != %p\n",
2910 			  uart_port, uport);
2911 
2912 	if (!uart_port) {
2913 		mutex_unlock(&port->mutex);
2914 		ret = -EINVAL;
2915 		goto out;
2916 	}
2917 	uport->flags |= UPF_DEAD;
2918 	mutex_unlock(&port->mutex);
2919 
2920 	/*
2921 	 * Remove the devices from the tty layer
2922 	 */
2923 	tty_port_unregister_device(port, drv->tty_driver, uport->line);
2924 
2925 	tty = tty_port_tty_get(port);
2926 	if (tty) {
2927 		tty_vhangup(port->tty);
2928 		tty_kref_put(tty);
2929 	}
2930 
2931 	/*
2932 	 * If the port is used as a console, unregister it
2933 	 */
2934 	if (uart_console(uport))
2935 		unregister_console(uport->cons);
2936 
2937 	/*
2938 	 * Free the port IO and memory resources, if any.
2939 	 */
2940 	if (uport->type != PORT_UNKNOWN && uport->ops->release_port)
2941 		uport->ops->release_port(uport);
2942 	kfree(uport->tty_groups);
2943 	kfree(uport->name);
2944 
2945 	/*
2946 	 * Indicate that there isn't a port here anymore.
2947 	 */
2948 	uport->type = PORT_UNKNOWN;
2949 
2950 	mutex_lock(&port->mutex);
2951 	WARN_ON(atomic_dec_return(&state->refcount) < 0);
2952 	wait_event(state->remove_wait, !atomic_read(&state->refcount));
2953 	state->uart_port = NULL;
2954 	mutex_unlock(&port->mutex);
2955 out:
2956 	mutex_unlock(&port_mutex);
2957 
2958 	return ret;
2959 }
2960 
2961 /*
2962  *	Are the two ports equivalent?
2963  */
2964 int uart_match_port(struct uart_port *port1, struct uart_port *port2)
2965 {
2966 	if (port1->iotype != port2->iotype)
2967 		return 0;
2968 
2969 	switch (port1->iotype) {
2970 	case UPIO_PORT:
2971 		return (port1->iobase == port2->iobase);
2972 	case UPIO_HUB6:
2973 		return (port1->iobase == port2->iobase) &&
2974 		       (port1->hub6   == port2->hub6);
2975 	case UPIO_MEM:
2976 	case UPIO_MEM16:
2977 	case UPIO_MEM32:
2978 	case UPIO_MEM32BE:
2979 	case UPIO_AU:
2980 	case UPIO_TSI:
2981 		return (port1->mapbase == port2->mapbase);
2982 	}
2983 	return 0;
2984 }
2985 EXPORT_SYMBOL(uart_match_port);
2986 
2987 /**
2988  *	uart_handle_dcd_change - handle a change of carrier detect state
2989  *	@uport: uart_port structure for the open port
2990  *	@status: new carrier detect status, nonzero if active
2991  *
2992  *	Caller must hold uport->lock
2993  */
2994 void uart_handle_dcd_change(struct uart_port *uport, unsigned int status)
2995 {
2996 	struct tty_port *port = &uport->state->port;
2997 	struct tty_struct *tty = port->tty;
2998 	struct tty_ldisc *ld;
2999 
3000 	lockdep_assert_held_once(&uport->lock);
3001 
3002 	if (tty) {
3003 		ld = tty_ldisc_ref(tty);
3004 		if (ld) {
3005 			if (ld->ops->dcd_change)
3006 				ld->ops->dcd_change(tty, status);
3007 			tty_ldisc_deref(ld);
3008 		}
3009 	}
3010 
3011 	uport->icount.dcd++;
3012 
3013 	if (uart_dcd_enabled(uport)) {
3014 		if (status)
3015 			wake_up_interruptible(&port->open_wait);
3016 		else if (tty)
3017 			tty_hangup(tty);
3018 	}
3019 }
3020 EXPORT_SYMBOL_GPL(uart_handle_dcd_change);
3021 
3022 /**
3023  *	uart_handle_cts_change - handle a change of clear-to-send state
3024  *	@uport: uart_port structure for the open port
3025  *	@status: new clear to send status, nonzero if active
3026  *
3027  *	Caller must hold uport->lock
3028  */
3029 void uart_handle_cts_change(struct uart_port *uport, unsigned int status)
3030 {
3031 	lockdep_assert_held_once(&uport->lock);
3032 
3033 	uport->icount.cts++;
3034 
3035 	if (uart_softcts_mode(uport)) {
3036 		if (uport->hw_stopped) {
3037 			if (status) {
3038 				uport->hw_stopped = 0;
3039 				uport->ops->start_tx(uport);
3040 				uart_write_wakeup(uport);
3041 			}
3042 		} else {
3043 			if (!status) {
3044 				uport->hw_stopped = 1;
3045 				uport->ops->stop_tx(uport);
3046 			}
3047 		}
3048 
3049 	}
3050 }
3051 EXPORT_SYMBOL_GPL(uart_handle_cts_change);
3052 
3053 /**
3054  * uart_insert_char - push a char to the uart layer
3055  *
3056  * User is responsible to call tty_flip_buffer_push when they are done with
3057  * insertion.
3058  *
3059  * @port: corresponding port
3060  * @status: state of the serial port RX buffer (LSR for 8250)
3061  * @overrun: mask of overrun bits in @status
3062  * @ch: character to push
3063  * @flag: flag for the character (see TTY_NORMAL and friends)
3064  */
3065 void uart_insert_char(struct uart_port *port, unsigned int status,
3066 		 unsigned int overrun, unsigned int ch, unsigned int flag)
3067 {
3068 	struct tty_port *tport = &port->state->port;
3069 
3070 	if ((status & port->ignore_status_mask & ~overrun) == 0)
3071 		if (tty_insert_flip_char(tport, ch, flag) == 0)
3072 			++port->icount.buf_overrun;
3073 
3074 	/*
3075 	 * Overrun is special.  Since it's reported immediately,
3076 	 * it doesn't affect the current character.
3077 	 */
3078 	if (status & ~port->ignore_status_mask & overrun)
3079 		if (tty_insert_flip_char(tport, 0, TTY_OVERRUN) == 0)
3080 			++port->icount.buf_overrun;
3081 }
3082 EXPORT_SYMBOL_GPL(uart_insert_char);
3083 
3084 EXPORT_SYMBOL(uart_write_wakeup);
3085 EXPORT_SYMBOL(uart_register_driver);
3086 EXPORT_SYMBOL(uart_unregister_driver);
3087 EXPORT_SYMBOL(uart_suspend_port);
3088 EXPORT_SYMBOL(uart_resume_port);
3089 EXPORT_SYMBOL(uart_add_one_port);
3090 EXPORT_SYMBOL(uart_remove_one_port);
3091 
3092 /**
3093  * uart_get_rs485_mode() - retrieve rs485 properties for given uart
3094  * @dev: uart device
3095  * @rs485conf: output parameter
3096  *
3097  * This function implements the device tree binding described in
3098  * Documentation/devicetree/bindings/serial/rs485.txt.
3099  */
3100 void uart_get_rs485_mode(struct device *dev, struct serial_rs485 *rs485conf)
3101 {
3102 	u32 rs485_delay[2];
3103 	int ret;
3104 
3105 	ret = device_property_read_u32_array(dev, "rs485-rts-delay",
3106 					     rs485_delay, 2);
3107 	if (!ret) {
3108 		rs485conf->delay_rts_before_send = rs485_delay[0];
3109 		rs485conf->delay_rts_after_send = rs485_delay[1];
3110 	} else {
3111 		rs485conf->delay_rts_before_send = 0;
3112 		rs485conf->delay_rts_after_send = 0;
3113 	}
3114 
3115 	/*
3116 	 * Clear full-duplex and enabled flags, set RTS polarity to active high
3117 	 * to get to a defined state with the following properties:
3118 	 */
3119 	rs485conf->flags &= ~(SER_RS485_RX_DURING_TX | SER_RS485_ENABLED |
3120 			      SER_RS485_RTS_AFTER_SEND);
3121 	rs485conf->flags |= SER_RS485_RTS_ON_SEND;
3122 
3123 	if (device_property_read_bool(dev, "rs485-rx-during-tx"))
3124 		rs485conf->flags |= SER_RS485_RX_DURING_TX;
3125 
3126 	if (device_property_read_bool(dev, "linux,rs485-enabled-at-boot-time"))
3127 		rs485conf->flags |= SER_RS485_ENABLED;
3128 
3129 	if (device_property_read_bool(dev, "rs485-rts-active-low")) {
3130 		rs485conf->flags &= ~SER_RS485_RTS_ON_SEND;
3131 		rs485conf->flags |= SER_RS485_RTS_AFTER_SEND;
3132 	}
3133 }
3134 EXPORT_SYMBOL_GPL(uart_get_rs485_mode);
3135 
3136 MODULE_DESCRIPTION("Serial driver core");
3137 MODULE_LICENSE("GPL");
3138