xref: /openbmc/linux/drivers/tty/serial/serial_core.c (revision e418d911)
1 // SPDX-License-Identifier: GPL-2.0+
2 /*
3  *  Driver core for serial ports
4  *
5  *  Based on drivers/char/serial.c, by Linus Torvalds, Theodore Ts'o.
6  *
7  *  Copyright 1999 ARM Limited
8  *  Copyright (C) 2000-2001 Deep Blue Solutions Ltd.
9  */
10 #include <linux/module.h>
11 #include <linux/tty.h>
12 #include <linux/tty_flip.h>
13 #include <linux/slab.h>
14 #include <linux/sched/signal.h>
15 #include <linux/init.h>
16 #include <linux/console.h>
17 #include <linux/gpio/consumer.h>
18 #include <linux/kernel.h>
19 #include <linux/of.h>
20 #include <linux/pm_runtime.h>
21 #include <linux/proc_fs.h>
22 #include <linux/seq_file.h>
23 #include <linux/device.h>
24 #include <linux/serial.h> /* for serial_state and serial_icounter_struct */
25 #include <linux/serial_core.h>
26 #include <linux/sysrq.h>
27 #include <linux/delay.h>
28 #include <linux/mutex.h>
29 #include <linux/math64.h>
30 #include <linux/security.h>
31 
32 #include <linux/irq.h>
33 #include <linux/uaccess.h>
34 
35 #include "serial_base.h"
36 
37 /*
38  * This is used to lock changes in serial line configuration.
39  */
40 static DEFINE_MUTEX(port_mutex);
41 
42 /*
43  * lockdep: port->lock is initialized in two places, but we
44  *          want only one lock-class:
45  */
46 static struct lock_class_key port_lock_key;
47 
48 #define HIGH_BITS_OFFSET	((sizeof(long)-sizeof(int))*8)
49 
50 /*
51  * Max time with active RTS before/after data is sent.
52  */
53 #define RS485_MAX_RTS_DELAY	100 /* msecs */
54 
55 static void uart_change_pm(struct uart_state *state,
56 			   enum uart_pm_state pm_state);
57 
58 static void uart_port_shutdown(struct tty_port *port);
59 
uart_dcd_enabled(struct uart_port * uport)60 static int uart_dcd_enabled(struct uart_port *uport)
61 {
62 	return !!(uport->status & UPSTAT_DCD_ENABLE);
63 }
64 
uart_port_ref(struct uart_state * state)65 static inline struct uart_port *uart_port_ref(struct uart_state *state)
66 {
67 	if (atomic_add_unless(&state->refcount, 1, 0))
68 		return state->uart_port;
69 	return NULL;
70 }
71 
uart_port_deref(struct uart_port * uport)72 static inline void uart_port_deref(struct uart_port *uport)
73 {
74 	if (atomic_dec_and_test(&uport->state->refcount))
75 		wake_up(&uport->state->remove_wait);
76 }
77 
78 #define uart_port_lock(state, flags)					\
79 	({								\
80 		struct uart_port *__uport = uart_port_ref(state);	\
81 		if (__uport)						\
82 			spin_lock_irqsave(&__uport->lock, flags);	\
83 		__uport;						\
84 	})
85 
86 #define uart_port_unlock(uport, flags)					\
87 	({								\
88 		struct uart_port *__uport = uport;			\
89 		if (__uport) {						\
90 			spin_unlock_irqrestore(&__uport->lock, flags);	\
91 			uart_port_deref(__uport);			\
92 		}							\
93 	})
94 
uart_port_check(struct uart_state * state)95 static inline struct uart_port *uart_port_check(struct uart_state *state)
96 {
97 	lockdep_assert_held(&state->port.mutex);
98 	return state->uart_port;
99 }
100 
101 /**
102  * uart_write_wakeup - schedule write processing
103  * @port: port to be processed
104  *
105  * This routine is used by the interrupt handler to schedule processing in the
106  * software interrupt portion of the driver. A driver is expected to call this
107  * function when the number of characters in the transmit buffer have dropped
108  * below a threshold.
109  *
110  * Locking: @port->lock should be held
111  */
uart_write_wakeup(struct uart_port * port)112 void uart_write_wakeup(struct uart_port *port)
113 {
114 	struct uart_state *state = port->state;
115 	/*
116 	 * This means you called this function _after_ the port was
117 	 * closed.  No cookie for you.
118 	 */
119 	BUG_ON(!state);
120 	tty_port_tty_wakeup(&state->port);
121 }
122 EXPORT_SYMBOL(uart_write_wakeup);
123 
uart_stop(struct tty_struct * tty)124 static void uart_stop(struct tty_struct *tty)
125 {
126 	struct uart_state *state = tty->driver_data;
127 	struct uart_port *port;
128 	unsigned long flags;
129 
130 	port = uart_port_lock(state, flags);
131 	if (port)
132 		port->ops->stop_tx(port);
133 	uart_port_unlock(port, flags);
134 }
135 
__uart_start(struct uart_state * state)136 static void __uart_start(struct uart_state *state)
137 {
138 	struct uart_port *port = state->uart_port;
139 	struct serial_port_device *port_dev;
140 	int err;
141 
142 	if (!port || port->flags & UPF_DEAD || uart_tx_stopped(port))
143 		return;
144 
145 	port_dev = port->port_dev;
146 
147 	/* Increment the runtime PM usage count for the active check below */
148 	err = pm_runtime_get(&port_dev->dev);
149 	if (err < 0 && err != -EINPROGRESS) {
150 		pm_runtime_put_noidle(&port_dev->dev);
151 		return;
152 	}
153 
154 	/*
155 	 * Start TX if enabled, and kick runtime PM. If the device is not
156 	 * enabled, serial_port_runtime_resume() calls start_tx() again
157 	 * after enabling the device.
158 	 */
159 	if (!pm_runtime_enabled(port->dev) || pm_runtime_active(port->dev))
160 		port->ops->start_tx(port);
161 	pm_runtime_mark_last_busy(&port_dev->dev);
162 	pm_runtime_put_autosuspend(&port_dev->dev);
163 }
164 
uart_start(struct tty_struct * tty)165 static void uart_start(struct tty_struct *tty)
166 {
167 	struct uart_state *state = tty->driver_data;
168 	struct uart_port *port;
169 	unsigned long flags;
170 
171 	port = uart_port_lock(state, flags);
172 	__uart_start(state);
173 	uart_port_unlock(port, flags);
174 }
175 
176 static void
uart_update_mctrl(struct uart_port * port,unsigned int set,unsigned int clear)177 uart_update_mctrl(struct uart_port *port, unsigned int set, unsigned int clear)
178 {
179 	unsigned long flags;
180 	unsigned int old;
181 
182 	spin_lock_irqsave(&port->lock, flags);
183 	old = port->mctrl;
184 	port->mctrl = (old & ~clear) | set;
185 	if (old != port->mctrl && !(port->rs485.flags & SER_RS485_ENABLED))
186 		port->ops->set_mctrl(port, port->mctrl);
187 	spin_unlock_irqrestore(&port->lock, flags);
188 }
189 
190 #define uart_set_mctrl(port, set)	uart_update_mctrl(port, set, 0)
191 #define uart_clear_mctrl(port, clear)	uart_update_mctrl(port, 0, clear)
192 
uart_port_dtr_rts(struct uart_port * uport,bool active)193 static void uart_port_dtr_rts(struct uart_port *uport, bool active)
194 {
195 	if (active)
196 		uart_set_mctrl(uport, TIOCM_DTR | TIOCM_RTS);
197 	else
198 		uart_clear_mctrl(uport, TIOCM_DTR | TIOCM_RTS);
199 }
200 
201 /* Caller holds port mutex */
uart_change_line_settings(struct tty_struct * tty,struct uart_state * state,const struct ktermios * old_termios)202 static void uart_change_line_settings(struct tty_struct *tty, struct uart_state *state,
203 				      const struct ktermios *old_termios)
204 {
205 	struct uart_port *uport = uart_port_check(state);
206 	struct ktermios *termios;
207 	bool old_hw_stopped;
208 
209 	/*
210 	 * If we have no tty, termios, or the port does not exist,
211 	 * then we can't set the parameters for this port.
212 	 */
213 	if (!tty || uport->type == PORT_UNKNOWN)
214 		return;
215 
216 	termios = &tty->termios;
217 	uport->ops->set_termios(uport, termios, old_termios);
218 
219 	/*
220 	 * Set modem status enables based on termios cflag
221 	 */
222 	spin_lock_irq(&uport->lock);
223 	if (termios->c_cflag & CRTSCTS)
224 		uport->status |= UPSTAT_CTS_ENABLE;
225 	else
226 		uport->status &= ~UPSTAT_CTS_ENABLE;
227 
228 	if (termios->c_cflag & CLOCAL)
229 		uport->status &= ~UPSTAT_DCD_ENABLE;
230 	else
231 		uport->status |= UPSTAT_DCD_ENABLE;
232 
233 	/* reset sw-assisted CTS flow control based on (possibly) new mode */
234 	old_hw_stopped = uport->hw_stopped;
235 	uport->hw_stopped = uart_softcts_mode(uport) &&
236 			    !(uport->ops->get_mctrl(uport) & TIOCM_CTS);
237 	if (uport->hw_stopped != old_hw_stopped) {
238 		if (!old_hw_stopped)
239 			uport->ops->stop_tx(uport);
240 		else
241 			__uart_start(state);
242 	}
243 	spin_unlock_irq(&uport->lock);
244 }
245 
246 /*
247  * Startup the port.  This will be called once per open.  All calls
248  * will be serialised by the per-port mutex.
249  */
uart_port_startup(struct tty_struct * tty,struct uart_state * state,bool init_hw)250 static int uart_port_startup(struct tty_struct *tty, struct uart_state *state,
251 			     bool init_hw)
252 {
253 	struct uart_port *uport = uart_port_check(state);
254 	unsigned long flags;
255 	unsigned long page;
256 	int retval = 0;
257 
258 	if (uport->type == PORT_UNKNOWN)
259 		return 1;
260 
261 	/*
262 	 * Make sure the device is in D0 state.
263 	 */
264 	uart_change_pm(state, UART_PM_STATE_ON);
265 
266 	/*
267 	 * Initialise and allocate the transmit and temporary
268 	 * buffer.
269 	 */
270 	page = get_zeroed_page(GFP_KERNEL);
271 	if (!page)
272 		return -ENOMEM;
273 
274 	uart_port_lock(state, flags);
275 	if (!state->xmit.buf) {
276 		state->xmit.buf = (unsigned char *) page;
277 		uart_circ_clear(&state->xmit);
278 		uart_port_unlock(uport, flags);
279 	} else {
280 		uart_port_unlock(uport, flags);
281 		/*
282 		 * Do not free() the page under the port lock, see
283 		 * uart_shutdown().
284 		 */
285 		free_page(page);
286 	}
287 
288 	retval = uport->ops->startup(uport);
289 	if (retval == 0) {
290 		if (uart_console(uport) && uport->cons->cflag) {
291 			tty->termios.c_cflag = uport->cons->cflag;
292 			tty->termios.c_ispeed = uport->cons->ispeed;
293 			tty->termios.c_ospeed = uport->cons->ospeed;
294 			uport->cons->cflag = 0;
295 			uport->cons->ispeed = 0;
296 			uport->cons->ospeed = 0;
297 		}
298 		/*
299 		 * Initialise the hardware port settings.
300 		 */
301 		uart_change_line_settings(tty, state, NULL);
302 
303 		/*
304 		 * Setup the RTS and DTR signals once the
305 		 * port is open and ready to respond.
306 		 */
307 		if (init_hw && C_BAUD(tty))
308 			uart_port_dtr_rts(uport, true);
309 	}
310 
311 	/*
312 	 * This is to allow setserial on this port. People may want to set
313 	 * port/irq/type and then reconfigure the port properly if it failed
314 	 * now.
315 	 */
316 	if (retval && capable(CAP_SYS_ADMIN))
317 		return 1;
318 
319 	return retval;
320 }
321 
uart_startup(struct tty_struct * tty,struct uart_state * state,bool init_hw)322 static int uart_startup(struct tty_struct *tty, struct uart_state *state,
323 			bool init_hw)
324 {
325 	struct tty_port *port = &state->port;
326 	struct uart_port *uport;
327 	int retval;
328 
329 	if (tty_port_initialized(port))
330 		goto out_base_port_startup;
331 
332 	retval = uart_port_startup(tty, state, init_hw);
333 	if (retval) {
334 		set_bit(TTY_IO_ERROR, &tty->flags);
335 		return retval;
336 	}
337 
338 out_base_port_startup:
339 	uport = uart_port_check(state);
340 	if (!uport)
341 		return -EIO;
342 
343 	serial_base_port_startup(uport);
344 
345 	return 0;
346 }
347 
348 /*
349  * This routine will shutdown a serial port; interrupts are disabled, and
350  * DTR is dropped if the hangup on close termio flag is on.  Calls to
351  * uart_shutdown are serialised by the per-port semaphore.
352  *
353  * uport == NULL if uart_port has already been removed
354  */
uart_shutdown(struct tty_struct * tty,struct uart_state * state)355 static void uart_shutdown(struct tty_struct *tty, struct uart_state *state)
356 {
357 	struct uart_port *uport = uart_port_check(state);
358 	struct tty_port *port = &state->port;
359 	unsigned long flags;
360 	char *xmit_buf = NULL;
361 
362 	/*
363 	 * Set the TTY IO error marker
364 	 */
365 	if (tty)
366 		set_bit(TTY_IO_ERROR, &tty->flags);
367 
368 	if (uport)
369 		serial_base_port_shutdown(uport);
370 
371 	if (tty_port_initialized(port)) {
372 		tty_port_set_initialized(port, false);
373 
374 		/*
375 		 * Turn off DTR and RTS early.
376 		 */
377 		if (uport) {
378 			if (uart_console(uport) && tty) {
379 				uport->cons->cflag = tty->termios.c_cflag;
380 				uport->cons->ispeed = tty->termios.c_ispeed;
381 				uport->cons->ospeed = tty->termios.c_ospeed;
382 			}
383 
384 			if (!tty || C_HUPCL(tty))
385 				uart_port_dtr_rts(uport, false);
386 		}
387 
388 		uart_port_shutdown(port);
389 	}
390 
391 	/*
392 	 * It's possible for shutdown to be called after suspend if we get
393 	 * a DCD drop (hangup) at just the right time.  Clear suspended bit so
394 	 * we don't try to resume a port that has been shutdown.
395 	 */
396 	tty_port_set_suspended(port, false);
397 
398 	/*
399 	 * Do not free() the transmit buffer page under the port lock since
400 	 * this can create various circular locking scenarios. For instance,
401 	 * console driver may need to allocate/free a debug object, which
402 	 * can endup in printk() recursion.
403 	 */
404 	uart_port_lock(state, flags);
405 	xmit_buf = state->xmit.buf;
406 	state->xmit.buf = NULL;
407 	uart_port_unlock(uport, flags);
408 
409 	free_page((unsigned long)xmit_buf);
410 }
411 
412 /**
413  * uart_update_timeout - update per-port frame timing information
414  * @port: uart_port structure describing the port
415  * @cflag: termios cflag value
416  * @baud: speed of the port
417  *
418  * Set the @port frame timing information from which the FIFO timeout value is
419  * derived. The @cflag value should reflect the actual hardware settings as
420  * number of bits, parity, stop bits and baud rate is taken into account here.
421  *
422  * Locking: caller is expected to take @port->lock
423  */
424 void
uart_update_timeout(struct uart_port * port,unsigned int cflag,unsigned int baud)425 uart_update_timeout(struct uart_port *port, unsigned int cflag,
426 		    unsigned int baud)
427 {
428 	unsigned int size = tty_get_frame_size(cflag);
429 	u64 frame_time;
430 
431 	frame_time = (u64)size * NSEC_PER_SEC;
432 	port->frame_time = DIV64_U64_ROUND_UP(frame_time, baud);
433 }
434 EXPORT_SYMBOL(uart_update_timeout);
435 
436 /**
437  * uart_get_baud_rate - return baud rate for a particular port
438  * @port: uart_port structure describing the port in question.
439  * @termios: desired termios settings
440  * @old: old termios (or %NULL)
441  * @min: minimum acceptable baud rate
442  * @max: maximum acceptable baud rate
443  *
444  * Decode the termios structure into a numeric baud rate, taking account of the
445  * magic 38400 baud rate (with spd_* flags), and mapping the %B0 rate to 9600
446  * baud.
447  *
448  * If the new baud rate is invalid, try the @old termios setting. If it's still
449  * invalid, we try 9600 baud.
450  *
451  * The @termios structure is updated to reflect the baud rate we're actually
452  * going to be using. Don't do this for the case where B0 is requested ("hang
453  * up").
454  *
455  * Locking: caller dependent
456  */
457 unsigned int
uart_get_baud_rate(struct uart_port * port,struct ktermios * termios,const struct ktermios * old,unsigned int min,unsigned int max)458 uart_get_baud_rate(struct uart_port *port, struct ktermios *termios,
459 		   const struct ktermios *old, unsigned int min, unsigned int max)
460 {
461 	unsigned int try;
462 	unsigned int baud;
463 	unsigned int altbaud;
464 	int hung_up = 0;
465 	upf_t flags = port->flags & UPF_SPD_MASK;
466 
467 	switch (flags) {
468 	case UPF_SPD_HI:
469 		altbaud = 57600;
470 		break;
471 	case UPF_SPD_VHI:
472 		altbaud = 115200;
473 		break;
474 	case UPF_SPD_SHI:
475 		altbaud = 230400;
476 		break;
477 	case UPF_SPD_WARP:
478 		altbaud = 460800;
479 		break;
480 	default:
481 		altbaud = 38400;
482 		break;
483 	}
484 
485 	for (try = 0; try < 2; try++) {
486 		baud = tty_termios_baud_rate(termios);
487 
488 		/*
489 		 * The spd_hi, spd_vhi, spd_shi, spd_warp kludge...
490 		 * Die! Die! Die!
491 		 */
492 		if (try == 0 && baud == 38400)
493 			baud = altbaud;
494 
495 		/*
496 		 * Special case: B0 rate.
497 		 */
498 		if (baud == 0) {
499 			hung_up = 1;
500 			baud = 9600;
501 		}
502 
503 		if (baud >= min && baud <= max)
504 			return baud;
505 
506 		/*
507 		 * Oops, the quotient was zero.  Try again with
508 		 * the old baud rate if possible.
509 		 */
510 		termios->c_cflag &= ~CBAUD;
511 		if (old) {
512 			baud = tty_termios_baud_rate(old);
513 			if (!hung_up)
514 				tty_termios_encode_baud_rate(termios,
515 								baud, baud);
516 			old = NULL;
517 			continue;
518 		}
519 
520 		/*
521 		 * As a last resort, if the range cannot be met then clip to
522 		 * the nearest chip supported rate.
523 		 */
524 		if (!hung_up) {
525 			if (baud <= min)
526 				tty_termios_encode_baud_rate(termios,
527 							min + 1, min + 1);
528 			else
529 				tty_termios_encode_baud_rate(termios,
530 							max - 1, max - 1);
531 		}
532 	}
533 	/* Should never happen */
534 	WARN_ON(1);
535 	return 0;
536 }
537 EXPORT_SYMBOL(uart_get_baud_rate);
538 
539 /**
540  * uart_get_divisor - return uart clock divisor
541  * @port: uart_port structure describing the port
542  * @baud: desired baud rate
543  *
544  * Calculate the divisor (baud_base / baud) for the specified @baud,
545  * appropriately rounded.
546  *
547  * If 38400 baud and custom divisor is selected, return the custom divisor
548  * instead.
549  *
550  * Locking: caller dependent
551  */
552 unsigned int
uart_get_divisor(struct uart_port * port,unsigned int baud)553 uart_get_divisor(struct uart_port *port, unsigned int baud)
554 {
555 	unsigned int quot;
556 
557 	/*
558 	 * Old custom speed handling.
559 	 */
560 	if (baud == 38400 && (port->flags & UPF_SPD_MASK) == UPF_SPD_CUST)
561 		quot = port->custom_divisor;
562 	else
563 		quot = DIV_ROUND_CLOSEST(port->uartclk, 16 * baud);
564 
565 	return quot;
566 }
567 EXPORT_SYMBOL(uart_get_divisor);
568 
uart_put_char(struct tty_struct * tty,u8 c)569 static int uart_put_char(struct tty_struct *tty, u8 c)
570 {
571 	struct uart_state *state = tty->driver_data;
572 	struct uart_port *port;
573 	struct circ_buf *circ;
574 	unsigned long flags;
575 	int ret = 0;
576 
577 	circ = &state->xmit;
578 	port = uart_port_lock(state, flags);
579 	if (!circ->buf) {
580 		uart_port_unlock(port, flags);
581 		return 0;
582 	}
583 
584 	if (port && uart_circ_chars_free(circ) != 0) {
585 		circ->buf[circ->head] = c;
586 		circ->head = (circ->head + 1) & (UART_XMIT_SIZE - 1);
587 		ret = 1;
588 	}
589 	uart_port_unlock(port, flags);
590 	return ret;
591 }
592 
uart_flush_chars(struct tty_struct * tty)593 static void uart_flush_chars(struct tty_struct *tty)
594 {
595 	uart_start(tty);
596 }
597 
uart_write(struct tty_struct * tty,const u8 * buf,size_t count)598 static ssize_t uart_write(struct tty_struct *tty, const u8 *buf, size_t count)
599 {
600 	struct uart_state *state = tty->driver_data;
601 	struct uart_port *port;
602 	struct circ_buf *circ;
603 	unsigned long flags;
604 	int c, ret = 0;
605 
606 	/*
607 	 * This means you called this function _after_ the port was
608 	 * closed.  No cookie for you.
609 	 */
610 	if (WARN_ON(!state))
611 		return -EL3HLT;
612 
613 	port = uart_port_lock(state, flags);
614 	circ = &state->xmit;
615 	if (!circ->buf) {
616 		uart_port_unlock(port, flags);
617 		return 0;
618 	}
619 
620 	while (port) {
621 		c = CIRC_SPACE_TO_END(circ->head, circ->tail, UART_XMIT_SIZE);
622 		if (count < c)
623 			c = count;
624 		if (c <= 0)
625 			break;
626 		memcpy(circ->buf + circ->head, buf, c);
627 		circ->head = (circ->head + c) & (UART_XMIT_SIZE - 1);
628 		buf += c;
629 		count -= c;
630 		ret += c;
631 	}
632 
633 	__uart_start(state);
634 	uart_port_unlock(port, flags);
635 	return ret;
636 }
637 
uart_write_room(struct tty_struct * tty)638 static unsigned int uart_write_room(struct tty_struct *tty)
639 {
640 	struct uart_state *state = tty->driver_data;
641 	struct uart_port *port;
642 	unsigned long flags;
643 	unsigned int ret;
644 
645 	port = uart_port_lock(state, flags);
646 	ret = uart_circ_chars_free(&state->xmit);
647 	uart_port_unlock(port, flags);
648 	return ret;
649 }
650 
uart_chars_in_buffer(struct tty_struct * tty)651 static unsigned int uart_chars_in_buffer(struct tty_struct *tty)
652 {
653 	struct uart_state *state = tty->driver_data;
654 	struct uart_port *port;
655 	unsigned long flags;
656 	unsigned int ret;
657 
658 	port = uart_port_lock(state, flags);
659 	ret = uart_circ_chars_pending(&state->xmit);
660 	uart_port_unlock(port, flags);
661 	return ret;
662 }
663 
uart_flush_buffer(struct tty_struct * tty)664 static void uart_flush_buffer(struct tty_struct *tty)
665 {
666 	struct uart_state *state = tty->driver_data;
667 	struct uart_port *port;
668 	unsigned long flags;
669 
670 	/*
671 	 * This means you called this function _after_ the port was
672 	 * closed.  No cookie for you.
673 	 */
674 	if (WARN_ON(!state))
675 		return;
676 
677 	pr_debug("uart_flush_buffer(%d) called\n", tty->index);
678 
679 	port = uart_port_lock(state, flags);
680 	if (!port)
681 		return;
682 	uart_circ_clear(&state->xmit);
683 	if (port->ops->flush_buffer)
684 		port->ops->flush_buffer(port);
685 	uart_port_unlock(port, flags);
686 	tty_port_tty_wakeup(&state->port);
687 }
688 
689 /*
690  * This function performs low-level write of high-priority XON/XOFF
691  * character and accounting for it.
692  *
693  * Requires uart_port to implement .serial_out().
694  */
uart_xchar_out(struct uart_port * uport,int offset)695 void uart_xchar_out(struct uart_port *uport, int offset)
696 {
697 	serial_port_out(uport, offset, uport->x_char);
698 	uport->icount.tx++;
699 	uport->x_char = 0;
700 }
701 EXPORT_SYMBOL_GPL(uart_xchar_out);
702 
703 /*
704  * This function is used to send a high-priority XON/XOFF character to
705  * the device
706  */
uart_send_xchar(struct tty_struct * tty,char ch)707 static void uart_send_xchar(struct tty_struct *tty, char ch)
708 {
709 	struct uart_state *state = tty->driver_data;
710 	struct uart_port *port;
711 	unsigned long flags;
712 
713 	port = uart_port_ref(state);
714 	if (!port)
715 		return;
716 
717 	if (port->ops->send_xchar)
718 		port->ops->send_xchar(port, ch);
719 	else {
720 		spin_lock_irqsave(&port->lock, flags);
721 		port->x_char = ch;
722 		if (ch)
723 			port->ops->start_tx(port);
724 		spin_unlock_irqrestore(&port->lock, flags);
725 	}
726 	uart_port_deref(port);
727 }
728 
uart_throttle(struct tty_struct * tty)729 static void uart_throttle(struct tty_struct *tty)
730 {
731 	struct uart_state *state = tty->driver_data;
732 	upstat_t mask = UPSTAT_SYNC_FIFO;
733 	struct uart_port *port;
734 
735 	port = uart_port_ref(state);
736 	if (!port)
737 		return;
738 
739 	if (I_IXOFF(tty))
740 		mask |= UPSTAT_AUTOXOFF;
741 	if (C_CRTSCTS(tty))
742 		mask |= UPSTAT_AUTORTS;
743 
744 	if (port->status & mask) {
745 		port->ops->throttle(port);
746 		mask &= ~port->status;
747 	}
748 
749 	if (mask & UPSTAT_AUTORTS)
750 		uart_clear_mctrl(port, TIOCM_RTS);
751 
752 	if (mask & UPSTAT_AUTOXOFF)
753 		uart_send_xchar(tty, STOP_CHAR(tty));
754 
755 	uart_port_deref(port);
756 }
757 
uart_unthrottle(struct tty_struct * tty)758 static void uart_unthrottle(struct tty_struct *tty)
759 {
760 	struct uart_state *state = tty->driver_data;
761 	upstat_t mask = UPSTAT_SYNC_FIFO;
762 	struct uart_port *port;
763 
764 	port = uart_port_ref(state);
765 	if (!port)
766 		return;
767 
768 	if (I_IXOFF(tty))
769 		mask |= UPSTAT_AUTOXOFF;
770 	if (C_CRTSCTS(tty))
771 		mask |= UPSTAT_AUTORTS;
772 
773 	if (port->status & mask) {
774 		port->ops->unthrottle(port);
775 		mask &= ~port->status;
776 	}
777 
778 	if (mask & UPSTAT_AUTORTS)
779 		uart_set_mctrl(port, TIOCM_RTS);
780 
781 	if (mask & UPSTAT_AUTOXOFF)
782 		uart_send_xchar(tty, START_CHAR(tty));
783 
784 	uart_port_deref(port);
785 }
786 
uart_get_info(struct tty_port * port,struct serial_struct * retinfo)787 static int uart_get_info(struct tty_port *port, struct serial_struct *retinfo)
788 {
789 	struct uart_state *state = container_of(port, struct uart_state, port);
790 	struct uart_port *uport;
791 	int ret = -ENODEV;
792 
793 	/*
794 	 * Ensure the state we copy is consistent and no hardware changes
795 	 * occur as we go
796 	 */
797 	mutex_lock(&port->mutex);
798 	uport = uart_port_check(state);
799 	if (!uport)
800 		goto out;
801 
802 	retinfo->type	    = uport->type;
803 	retinfo->line	    = uport->line;
804 	retinfo->port	    = uport->iobase;
805 	if (HIGH_BITS_OFFSET)
806 		retinfo->port_high = (long) uport->iobase >> HIGH_BITS_OFFSET;
807 	retinfo->irq		    = uport->irq;
808 	retinfo->flags	    = (__force int)uport->flags;
809 	retinfo->xmit_fifo_size  = uport->fifosize;
810 	retinfo->baud_base	    = uport->uartclk / 16;
811 	retinfo->close_delay	    = jiffies_to_msecs(port->close_delay) / 10;
812 	retinfo->closing_wait    = port->closing_wait == ASYNC_CLOSING_WAIT_NONE ?
813 				ASYNC_CLOSING_WAIT_NONE :
814 				jiffies_to_msecs(port->closing_wait) / 10;
815 	retinfo->custom_divisor  = uport->custom_divisor;
816 	retinfo->hub6	    = uport->hub6;
817 	retinfo->io_type         = uport->iotype;
818 	retinfo->iomem_reg_shift = uport->regshift;
819 	retinfo->iomem_base      = (void *)(unsigned long)uport->mapbase;
820 
821 	ret = 0;
822 out:
823 	mutex_unlock(&port->mutex);
824 	return ret;
825 }
826 
uart_get_info_user(struct tty_struct * tty,struct serial_struct * ss)827 static int uart_get_info_user(struct tty_struct *tty,
828 			 struct serial_struct *ss)
829 {
830 	struct uart_state *state = tty->driver_data;
831 	struct tty_port *port = &state->port;
832 
833 	return uart_get_info(port, ss) < 0 ? -EIO : 0;
834 }
835 
uart_set_info(struct tty_struct * tty,struct tty_port * port,struct uart_state * state,struct serial_struct * new_info)836 static int uart_set_info(struct tty_struct *tty, struct tty_port *port,
837 			 struct uart_state *state,
838 			 struct serial_struct *new_info)
839 {
840 	struct uart_port *uport = uart_port_check(state);
841 	unsigned long new_port;
842 	unsigned int change_irq, change_port, closing_wait;
843 	unsigned int old_custom_divisor, close_delay;
844 	upf_t old_flags, new_flags;
845 	int retval = 0;
846 
847 	if (!uport)
848 		return -EIO;
849 
850 	new_port = new_info->port;
851 	if (HIGH_BITS_OFFSET)
852 		new_port += (unsigned long) new_info->port_high << HIGH_BITS_OFFSET;
853 
854 	new_info->irq = irq_canonicalize(new_info->irq);
855 	close_delay = msecs_to_jiffies(new_info->close_delay * 10);
856 	closing_wait = new_info->closing_wait == ASYNC_CLOSING_WAIT_NONE ?
857 			ASYNC_CLOSING_WAIT_NONE :
858 			msecs_to_jiffies(new_info->closing_wait * 10);
859 
860 
861 	change_irq  = !(uport->flags & UPF_FIXED_PORT)
862 		&& new_info->irq != uport->irq;
863 
864 	/*
865 	 * Since changing the 'type' of the port changes its resource
866 	 * allocations, we should treat type changes the same as
867 	 * IO port changes.
868 	 */
869 	change_port = !(uport->flags & UPF_FIXED_PORT)
870 		&& (new_port != uport->iobase ||
871 		    (unsigned long)new_info->iomem_base != uport->mapbase ||
872 		    new_info->hub6 != uport->hub6 ||
873 		    new_info->io_type != uport->iotype ||
874 		    new_info->iomem_reg_shift != uport->regshift ||
875 		    new_info->type != uport->type);
876 
877 	old_flags = uport->flags;
878 	new_flags = (__force upf_t)new_info->flags;
879 	old_custom_divisor = uport->custom_divisor;
880 
881 	if (!(uport->flags & UPF_FIXED_PORT)) {
882 		unsigned int uartclk = new_info->baud_base * 16;
883 		/* check needs to be done here before other settings made */
884 		if (uartclk == 0) {
885 			retval = -EINVAL;
886 			goto exit;
887 		}
888 	}
889 	if (!capable(CAP_SYS_ADMIN)) {
890 		retval = -EPERM;
891 		if (change_irq || change_port ||
892 		    (new_info->baud_base != uport->uartclk / 16) ||
893 		    (close_delay != port->close_delay) ||
894 		    (closing_wait != port->closing_wait) ||
895 		    (new_info->xmit_fifo_size &&
896 		     new_info->xmit_fifo_size != uport->fifosize) ||
897 		    (((new_flags ^ old_flags) & ~UPF_USR_MASK) != 0))
898 			goto exit;
899 		uport->flags = ((uport->flags & ~UPF_USR_MASK) |
900 			       (new_flags & UPF_USR_MASK));
901 		uport->custom_divisor = new_info->custom_divisor;
902 		goto check_and_exit;
903 	}
904 
905 	if (change_irq || change_port) {
906 		retval = security_locked_down(LOCKDOWN_TIOCSSERIAL);
907 		if (retval)
908 			goto exit;
909 	}
910 
911 	/*
912 	 * Ask the low level driver to verify the settings.
913 	 */
914 	if (uport->ops->verify_port)
915 		retval = uport->ops->verify_port(uport, new_info);
916 
917 	if ((new_info->irq >= nr_irqs) || (new_info->irq < 0) ||
918 	    (new_info->baud_base < 9600))
919 		retval = -EINVAL;
920 
921 	if (retval)
922 		goto exit;
923 
924 	if (change_port || change_irq) {
925 		retval = -EBUSY;
926 
927 		/*
928 		 * Make sure that we are the sole user of this port.
929 		 */
930 		if (tty_port_users(port) > 1)
931 			goto exit;
932 
933 		/*
934 		 * We need to shutdown the serial port at the old
935 		 * port/type/irq combination.
936 		 */
937 		uart_shutdown(tty, state);
938 	}
939 
940 	if (change_port) {
941 		unsigned long old_iobase, old_mapbase;
942 		unsigned int old_type, old_iotype, old_hub6, old_shift;
943 
944 		old_iobase = uport->iobase;
945 		old_mapbase = uport->mapbase;
946 		old_type = uport->type;
947 		old_hub6 = uport->hub6;
948 		old_iotype = uport->iotype;
949 		old_shift = uport->regshift;
950 
951 		/*
952 		 * Free and release old regions
953 		 */
954 		if (old_type != PORT_UNKNOWN && uport->ops->release_port)
955 			uport->ops->release_port(uport);
956 
957 		uport->iobase = new_port;
958 		uport->type = new_info->type;
959 		uport->hub6 = new_info->hub6;
960 		uport->iotype = new_info->io_type;
961 		uport->regshift = new_info->iomem_reg_shift;
962 		uport->mapbase = (unsigned long)new_info->iomem_base;
963 
964 		/*
965 		 * Claim and map the new regions
966 		 */
967 		if (uport->type != PORT_UNKNOWN && uport->ops->request_port) {
968 			retval = uport->ops->request_port(uport);
969 		} else {
970 			/* Always success - Jean II */
971 			retval = 0;
972 		}
973 
974 		/*
975 		 * If we fail to request resources for the
976 		 * new port, try to restore the old settings.
977 		 */
978 		if (retval) {
979 			uport->iobase = old_iobase;
980 			uport->type = old_type;
981 			uport->hub6 = old_hub6;
982 			uport->iotype = old_iotype;
983 			uport->regshift = old_shift;
984 			uport->mapbase = old_mapbase;
985 
986 			if (old_type != PORT_UNKNOWN) {
987 				retval = uport->ops->request_port(uport);
988 				/*
989 				 * If we failed to restore the old settings,
990 				 * we fail like this.
991 				 */
992 				if (retval)
993 					uport->type = PORT_UNKNOWN;
994 
995 				/*
996 				 * We failed anyway.
997 				 */
998 				retval = -EBUSY;
999 			}
1000 
1001 			/* Added to return the correct error -Ram Gupta */
1002 			goto exit;
1003 		}
1004 	}
1005 
1006 	if (change_irq)
1007 		uport->irq      = new_info->irq;
1008 	if (!(uport->flags & UPF_FIXED_PORT))
1009 		uport->uartclk  = new_info->baud_base * 16;
1010 	uport->flags            = (uport->flags & ~UPF_CHANGE_MASK) |
1011 				 (new_flags & UPF_CHANGE_MASK);
1012 	uport->custom_divisor   = new_info->custom_divisor;
1013 	port->close_delay     = close_delay;
1014 	port->closing_wait    = closing_wait;
1015 	if (new_info->xmit_fifo_size)
1016 		uport->fifosize = new_info->xmit_fifo_size;
1017 
1018  check_and_exit:
1019 	retval = 0;
1020 	if (uport->type == PORT_UNKNOWN)
1021 		goto exit;
1022 	if (tty_port_initialized(port)) {
1023 		if (((old_flags ^ uport->flags) & UPF_SPD_MASK) ||
1024 		    old_custom_divisor != uport->custom_divisor) {
1025 			/*
1026 			 * If they're setting up a custom divisor or speed,
1027 			 * instead of clearing it, then bitch about it.
1028 			 */
1029 			if (uport->flags & UPF_SPD_MASK) {
1030 				dev_notice_ratelimited(uport->dev,
1031 				       "%s sets custom speed on %s. This is deprecated.\n",
1032 				      current->comm,
1033 				      tty_name(port->tty));
1034 			}
1035 			uart_change_line_settings(tty, state, NULL);
1036 		}
1037 	} else {
1038 		retval = uart_startup(tty, state, true);
1039 		if (retval == 0)
1040 			tty_port_set_initialized(port, true);
1041 		if (retval > 0)
1042 			retval = 0;
1043 	}
1044  exit:
1045 	return retval;
1046 }
1047 
uart_set_info_user(struct tty_struct * tty,struct serial_struct * ss)1048 static int uart_set_info_user(struct tty_struct *tty, struct serial_struct *ss)
1049 {
1050 	struct uart_state *state = tty->driver_data;
1051 	struct tty_port *port = &state->port;
1052 	int retval;
1053 
1054 	down_write(&tty->termios_rwsem);
1055 	/*
1056 	 * This semaphore protects port->count.  It is also
1057 	 * very useful to prevent opens.  Also, take the
1058 	 * port configuration semaphore to make sure that a
1059 	 * module insertion/removal doesn't change anything
1060 	 * under us.
1061 	 */
1062 	mutex_lock(&port->mutex);
1063 	retval = uart_set_info(tty, port, state, ss);
1064 	mutex_unlock(&port->mutex);
1065 	up_write(&tty->termios_rwsem);
1066 	return retval;
1067 }
1068 
1069 /**
1070  * uart_get_lsr_info - get line status register info
1071  * @tty: tty associated with the UART
1072  * @state: UART being queried
1073  * @value: returned modem value
1074  */
uart_get_lsr_info(struct tty_struct * tty,struct uart_state * state,unsigned int __user * value)1075 static int uart_get_lsr_info(struct tty_struct *tty,
1076 			struct uart_state *state, unsigned int __user *value)
1077 {
1078 	struct uart_port *uport = uart_port_check(state);
1079 	unsigned int result;
1080 
1081 	result = uport->ops->tx_empty(uport);
1082 
1083 	/*
1084 	 * If we're about to load something into the transmit
1085 	 * register, we'll pretend the transmitter isn't empty to
1086 	 * avoid a race condition (depending on when the transmit
1087 	 * interrupt happens).
1088 	 */
1089 	if (uport->x_char ||
1090 	    ((uart_circ_chars_pending(&state->xmit) > 0) &&
1091 	     !uart_tx_stopped(uport)))
1092 		result &= ~TIOCSER_TEMT;
1093 
1094 	return put_user(result, value);
1095 }
1096 
uart_tiocmget(struct tty_struct * tty)1097 static int uart_tiocmget(struct tty_struct *tty)
1098 {
1099 	struct uart_state *state = tty->driver_data;
1100 	struct tty_port *port = &state->port;
1101 	struct uart_port *uport;
1102 	int result = -EIO;
1103 
1104 	mutex_lock(&port->mutex);
1105 	uport = uart_port_check(state);
1106 	if (!uport)
1107 		goto out;
1108 
1109 	if (!tty_io_error(tty)) {
1110 		result = uport->mctrl;
1111 		spin_lock_irq(&uport->lock);
1112 		result |= uport->ops->get_mctrl(uport);
1113 		spin_unlock_irq(&uport->lock);
1114 	}
1115 out:
1116 	mutex_unlock(&port->mutex);
1117 	return result;
1118 }
1119 
1120 static int
uart_tiocmset(struct tty_struct * tty,unsigned int set,unsigned int clear)1121 uart_tiocmset(struct tty_struct *tty, unsigned int set, unsigned int clear)
1122 {
1123 	struct uart_state *state = tty->driver_data;
1124 	struct tty_port *port = &state->port;
1125 	struct uart_port *uport;
1126 	int ret = -EIO;
1127 
1128 	mutex_lock(&port->mutex);
1129 	uport = uart_port_check(state);
1130 	if (!uport)
1131 		goto out;
1132 
1133 	if (!tty_io_error(tty)) {
1134 		uart_update_mctrl(uport, set, clear);
1135 		ret = 0;
1136 	}
1137 out:
1138 	mutex_unlock(&port->mutex);
1139 	return ret;
1140 }
1141 
uart_break_ctl(struct tty_struct * tty,int break_state)1142 static int uart_break_ctl(struct tty_struct *tty, int break_state)
1143 {
1144 	struct uart_state *state = tty->driver_data;
1145 	struct tty_port *port = &state->port;
1146 	struct uart_port *uport;
1147 	int ret = -EIO;
1148 
1149 	mutex_lock(&port->mutex);
1150 	uport = uart_port_check(state);
1151 	if (!uport)
1152 		goto out;
1153 
1154 	if (uport->type != PORT_UNKNOWN && uport->ops->break_ctl)
1155 		uport->ops->break_ctl(uport, break_state);
1156 	ret = 0;
1157 out:
1158 	mutex_unlock(&port->mutex);
1159 	return ret;
1160 }
1161 
uart_do_autoconfig(struct tty_struct * tty,struct uart_state * state)1162 static int uart_do_autoconfig(struct tty_struct *tty, struct uart_state *state)
1163 {
1164 	struct tty_port *port = &state->port;
1165 	struct uart_port *uport;
1166 	int flags, ret;
1167 
1168 	if (!capable(CAP_SYS_ADMIN))
1169 		return -EPERM;
1170 
1171 	/*
1172 	 * Take the per-port semaphore.  This prevents count from
1173 	 * changing, and hence any extra opens of the port while
1174 	 * we're auto-configuring.
1175 	 */
1176 	if (mutex_lock_interruptible(&port->mutex))
1177 		return -ERESTARTSYS;
1178 
1179 	uport = uart_port_check(state);
1180 	if (!uport) {
1181 		ret = -EIO;
1182 		goto out;
1183 	}
1184 
1185 	ret = -EBUSY;
1186 	if (tty_port_users(port) == 1) {
1187 		uart_shutdown(tty, state);
1188 
1189 		/*
1190 		 * If we already have a port type configured,
1191 		 * we must release its resources.
1192 		 */
1193 		if (uport->type != PORT_UNKNOWN && uport->ops->release_port)
1194 			uport->ops->release_port(uport);
1195 
1196 		flags = UART_CONFIG_TYPE;
1197 		if (uport->flags & UPF_AUTO_IRQ)
1198 			flags |= UART_CONFIG_IRQ;
1199 
1200 		/*
1201 		 * This will claim the ports resources if
1202 		 * a port is found.
1203 		 */
1204 		uport->ops->config_port(uport, flags);
1205 
1206 		ret = uart_startup(tty, state, true);
1207 		if (ret == 0)
1208 			tty_port_set_initialized(port, true);
1209 		if (ret > 0)
1210 			ret = 0;
1211 	}
1212 out:
1213 	mutex_unlock(&port->mutex);
1214 	return ret;
1215 }
1216 
uart_enable_ms(struct uart_port * uport)1217 static void uart_enable_ms(struct uart_port *uport)
1218 {
1219 	/*
1220 	 * Force modem status interrupts on
1221 	 */
1222 	if (uport->ops->enable_ms)
1223 		uport->ops->enable_ms(uport);
1224 }
1225 
1226 /*
1227  * Wait for any of the 4 modem inputs (DCD,RI,DSR,CTS) to change
1228  * - mask passed in arg for lines of interest
1229  *   (use |'ed TIOCM_RNG/DSR/CD/CTS for masking)
1230  * Caller should use TIOCGICOUNT to see which one it was
1231  *
1232  * FIXME: This wants extracting into a common all driver implementation
1233  * of TIOCMWAIT using tty_port.
1234  */
uart_wait_modem_status(struct uart_state * state,unsigned long arg)1235 static int uart_wait_modem_status(struct uart_state *state, unsigned long arg)
1236 {
1237 	struct uart_port *uport;
1238 	struct tty_port *port = &state->port;
1239 	DECLARE_WAITQUEUE(wait, current);
1240 	struct uart_icount cprev, cnow;
1241 	int ret;
1242 
1243 	/*
1244 	 * note the counters on entry
1245 	 */
1246 	uport = uart_port_ref(state);
1247 	if (!uport)
1248 		return -EIO;
1249 	spin_lock_irq(&uport->lock);
1250 	memcpy(&cprev, &uport->icount, sizeof(struct uart_icount));
1251 	uart_enable_ms(uport);
1252 	spin_unlock_irq(&uport->lock);
1253 
1254 	add_wait_queue(&port->delta_msr_wait, &wait);
1255 	for (;;) {
1256 		spin_lock_irq(&uport->lock);
1257 		memcpy(&cnow, &uport->icount, sizeof(struct uart_icount));
1258 		spin_unlock_irq(&uport->lock);
1259 
1260 		set_current_state(TASK_INTERRUPTIBLE);
1261 
1262 		if (((arg & TIOCM_RNG) && (cnow.rng != cprev.rng)) ||
1263 		    ((arg & TIOCM_DSR) && (cnow.dsr != cprev.dsr)) ||
1264 		    ((arg & TIOCM_CD)  && (cnow.dcd != cprev.dcd)) ||
1265 		    ((arg & TIOCM_CTS) && (cnow.cts != cprev.cts))) {
1266 			ret = 0;
1267 			break;
1268 		}
1269 
1270 		schedule();
1271 
1272 		/* see if a signal did it */
1273 		if (signal_pending(current)) {
1274 			ret = -ERESTARTSYS;
1275 			break;
1276 		}
1277 
1278 		cprev = cnow;
1279 	}
1280 	__set_current_state(TASK_RUNNING);
1281 	remove_wait_queue(&port->delta_msr_wait, &wait);
1282 	uart_port_deref(uport);
1283 
1284 	return ret;
1285 }
1286 
1287 /*
1288  * Get counter of input serial line interrupts (DCD,RI,DSR,CTS)
1289  * Return: write counters to the user passed counter struct
1290  * NB: both 1->0 and 0->1 transitions are counted except for
1291  *     RI where only 0->1 is counted.
1292  */
uart_get_icount(struct tty_struct * tty,struct serial_icounter_struct * icount)1293 static int uart_get_icount(struct tty_struct *tty,
1294 			  struct serial_icounter_struct *icount)
1295 {
1296 	struct uart_state *state = tty->driver_data;
1297 	struct uart_icount cnow;
1298 	struct uart_port *uport;
1299 
1300 	uport = uart_port_ref(state);
1301 	if (!uport)
1302 		return -EIO;
1303 	spin_lock_irq(&uport->lock);
1304 	memcpy(&cnow, &uport->icount, sizeof(struct uart_icount));
1305 	spin_unlock_irq(&uport->lock);
1306 	uart_port_deref(uport);
1307 
1308 	icount->cts         = cnow.cts;
1309 	icount->dsr         = cnow.dsr;
1310 	icount->rng         = cnow.rng;
1311 	icount->dcd         = cnow.dcd;
1312 	icount->rx          = cnow.rx;
1313 	icount->tx          = cnow.tx;
1314 	icount->frame       = cnow.frame;
1315 	icount->overrun     = cnow.overrun;
1316 	icount->parity      = cnow.parity;
1317 	icount->brk         = cnow.brk;
1318 	icount->buf_overrun = cnow.buf_overrun;
1319 
1320 	return 0;
1321 }
1322 
1323 #define SER_RS485_LEGACY_FLAGS	(SER_RS485_ENABLED | SER_RS485_RTS_ON_SEND | \
1324 				 SER_RS485_RTS_AFTER_SEND | SER_RS485_RX_DURING_TX | \
1325 				 SER_RS485_TERMINATE_BUS)
1326 
uart_check_rs485_flags(struct uart_port * port,struct serial_rs485 * rs485)1327 static int uart_check_rs485_flags(struct uart_port *port, struct serial_rs485 *rs485)
1328 {
1329 	u32 flags = rs485->flags;
1330 
1331 	/* Don't return -EINVAL for unsupported legacy flags */
1332 	flags &= ~SER_RS485_LEGACY_FLAGS;
1333 
1334 	/*
1335 	 * For any bit outside of the legacy ones that is not supported by
1336 	 * the driver, return -EINVAL.
1337 	 */
1338 	if (flags & ~port->rs485_supported.flags)
1339 		return -EINVAL;
1340 
1341 	/* Asking for address w/o addressing mode? */
1342 	if (!(rs485->flags & SER_RS485_ADDRB) &&
1343 	    (rs485->flags & (SER_RS485_ADDR_RECV|SER_RS485_ADDR_DEST)))
1344 		return -EINVAL;
1345 
1346 	/* Address given but not enabled? */
1347 	if (!(rs485->flags & SER_RS485_ADDR_RECV) && rs485->addr_recv)
1348 		return -EINVAL;
1349 	if (!(rs485->flags & SER_RS485_ADDR_DEST) && rs485->addr_dest)
1350 		return -EINVAL;
1351 
1352 	return 0;
1353 }
1354 
uart_sanitize_serial_rs485_delays(struct uart_port * port,struct serial_rs485 * rs485)1355 static void uart_sanitize_serial_rs485_delays(struct uart_port *port,
1356 					      struct serial_rs485 *rs485)
1357 {
1358 	if (!port->rs485_supported.delay_rts_before_send) {
1359 		if (rs485->delay_rts_before_send) {
1360 			dev_warn_ratelimited(port->dev,
1361 				"%s (%d): RTS delay before sending not supported\n",
1362 				port->name, port->line);
1363 		}
1364 		rs485->delay_rts_before_send = 0;
1365 	} else if (rs485->delay_rts_before_send > RS485_MAX_RTS_DELAY) {
1366 		rs485->delay_rts_before_send = RS485_MAX_RTS_DELAY;
1367 		dev_warn_ratelimited(port->dev,
1368 			"%s (%d): RTS delay before sending clamped to %u ms\n",
1369 			port->name, port->line, rs485->delay_rts_before_send);
1370 	}
1371 
1372 	if (!port->rs485_supported.delay_rts_after_send) {
1373 		if (rs485->delay_rts_after_send) {
1374 			dev_warn_ratelimited(port->dev,
1375 				"%s (%d): RTS delay after sending not supported\n",
1376 				port->name, port->line);
1377 		}
1378 		rs485->delay_rts_after_send = 0;
1379 	} else if (rs485->delay_rts_after_send > RS485_MAX_RTS_DELAY) {
1380 		rs485->delay_rts_after_send = RS485_MAX_RTS_DELAY;
1381 		dev_warn_ratelimited(port->dev,
1382 			"%s (%d): RTS delay after sending clamped to %u ms\n",
1383 			port->name, port->line, rs485->delay_rts_after_send);
1384 	}
1385 }
1386 
uart_sanitize_serial_rs485(struct uart_port * port,struct serial_rs485 * rs485)1387 static void uart_sanitize_serial_rs485(struct uart_port *port, struct serial_rs485 *rs485)
1388 {
1389 	u32 supported_flags = port->rs485_supported.flags;
1390 
1391 	if (!(rs485->flags & SER_RS485_ENABLED)) {
1392 		memset(rs485, 0, sizeof(*rs485));
1393 		return;
1394 	}
1395 
1396 	rs485->flags &= supported_flags;
1397 
1398 	/* Pick sane settings if the user hasn't */
1399 	if (!(rs485->flags & SER_RS485_RTS_ON_SEND) ==
1400 	    !(rs485->flags & SER_RS485_RTS_AFTER_SEND)) {
1401 		if (supported_flags & SER_RS485_RTS_ON_SEND) {
1402 			rs485->flags |= SER_RS485_RTS_ON_SEND;
1403 			rs485->flags &= ~SER_RS485_RTS_AFTER_SEND;
1404 
1405 			dev_warn_ratelimited(port->dev,
1406 				"%s (%d): invalid RTS setting, using RTS_ON_SEND instead\n",
1407 				port->name, port->line);
1408 		} else {
1409 			rs485->flags |= SER_RS485_RTS_AFTER_SEND;
1410 			rs485->flags &= ~SER_RS485_RTS_ON_SEND;
1411 
1412 			dev_warn_ratelimited(port->dev,
1413 				"%s (%d): invalid RTS setting, using RTS_AFTER_SEND instead\n",
1414 				port->name, port->line);
1415 		}
1416 	}
1417 
1418 	uart_sanitize_serial_rs485_delays(port, rs485);
1419 
1420 	/* Return clean padding area to userspace */
1421 	memset(rs485->padding0, 0, sizeof(rs485->padding0));
1422 	memset(rs485->padding1, 0, sizeof(rs485->padding1));
1423 }
1424 
uart_set_rs485_termination(struct uart_port * port,const struct serial_rs485 * rs485)1425 static void uart_set_rs485_termination(struct uart_port *port,
1426 				       const struct serial_rs485 *rs485)
1427 {
1428 	if (!(rs485->flags & SER_RS485_ENABLED))
1429 		return;
1430 
1431 	gpiod_set_value_cansleep(port->rs485_term_gpio,
1432 				 !!(rs485->flags & SER_RS485_TERMINATE_BUS));
1433 }
1434 
uart_set_rs485_rx_during_tx(struct uart_port * port,const struct serial_rs485 * rs485)1435 static void uart_set_rs485_rx_during_tx(struct uart_port *port,
1436 					const struct serial_rs485 *rs485)
1437 {
1438 	if (!(rs485->flags & SER_RS485_ENABLED))
1439 		return;
1440 
1441 	gpiod_set_value_cansleep(port->rs485_rx_during_tx_gpio,
1442 				 !!(rs485->flags & SER_RS485_RX_DURING_TX));
1443 }
1444 
uart_rs485_config(struct uart_port * port)1445 static int uart_rs485_config(struct uart_port *port)
1446 {
1447 	struct serial_rs485 *rs485 = &port->rs485;
1448 	unsigned long flags;
1449 	int ret;
1450 
1451 	if (!(rs485->flags & SER_RS485_ENABLED))
1452 		return 0;
1453 
1454 	uart_sanitize_serial_rs485(port, rs485);
1455 	uart_set_rs485_termination(port, rs485);
1456 	uart_set_rs485_rx_during_tx(port, rs485);
1457 
1458 	spin_lock_irqsave(&port->lock, flags);
1459 	ret = port->rs485_config(port, NULL, rs485);
1460 	spin_unlock_irqrestore(&port->lock, flags);
1461 	if (ret) {
1462 		memset(rs485, 0, sizeof(*rs485));
1463 		/* unset GPIOs */
1464 		gpiod_set_value_cansleep(port->rs485_term_gpio, 0);
1465 		gpiod_set_value_cansleep(port->rs485_rx_during_tx_gpio, 0);
1466 	}
1467 
1468 	return ret;
1469 }
1470 
uart_get_rs485_config(struct uart_port * port,struct serial_rs485 __user * rs485)1471 static int uart_get_rs485_config(struct uart_port *port,
1472 			 struct serial_rs485 __user *rs485)
1473 {
1474 	unsigned long flags;
1475 	struct serial_rs485 aux;
1476 
1477 	spin_lock_irqsave(&port->lock, flags);
1478 	aux = port->rs485;
1479 	spin_unlock_irqrestore(&port->lock, flags);
1480 
1481 	if (copy_to_user(rs485, &aux, sizeof(aux)))
1482 		return -EFAULT;
1483 
1484 	return 0;
1485 }
1486 
uart_set_rs485_config(struct tty_struct * tty,struct uart_port * port,struct serial_rs485 __user * rs485_user)1487 static int uart_set_rs485_config(struct tty_struct *tty, struct uart_port *port,
1488 			 struct serial_rs485 __user *rs485_user)
1489 {
1490 	struct serial_rs485 rs485;
1491 	int ret;
1492 	unsigned long flags;
1493 
1494 	if (!(port->rs485_supported.flags & SER_RS485_ENABLED))
1495 		return -ENOTTY;
1496 
1497 	if (copy_from_user(&rs485, rs485_user, sizeof(*rs485_user)))
1498 		return -EFAULT;
1499 
1500 	ret = uart_check_rs485_flags(port, &rs485);
1501 	if (ret)
1502 		return ret;
1503 	uart_sanitize_serial_rs485(port, &rs485);
1504 	uart_set_rs485_termination(port, &rs485);
1505 	uart_set_rs485_rx_during_tx(port, &rs485);
1506 
1507 	spin_lock_irqsave(&port->lock, flags);
1508 	ret = port->rs485_config(port, &tty->termios, &rs485);
1509 	if (!ret) {
1510 		port->rs485 = rs485;
1511 
1512 		/* Reset RTS and other mctrl lines when disabling RS485 */
1513 		if (!(rs485.flags & SER_RS485_ENABLED))
1514 			port->ops->set_mctrl(port, port->mctrl);
1515 	}
1516 	spin_unlock_irqrestore(&port->lock, flags);
1517 	if (ret) {
1518 		/* restore old GPIO settings */
1519 		gpiod_set_value_cansleep(port->rs485_term_gpio,
1520 			!!(port->rs485.flags & SER_RS485_TERMINATE_BUS));
1521 		gpiod_set_value_cansleep(port->rs485_rx_during_tx_gpio,
1522 			!!(port->rs485.flags & SER_RS485_RX_DURING_TX));
1523 		return ret;
1524 	}
1525 
1526 	if (copy_to_user(rs485_user, &port->rs485, sizeof(port->rs485)))
1527 		return -EFAULT;
1528 
1529 	return 0;
1530 }
1531 
uart_get_iso7816_config(struct uart_port * port,struct serial_iso7816 __user * iso7816)1532 static int uart_get_iso7816_config(struct uart_port *port,
1533 				   struct serial_iso7816 __user *iso7816)
1534 {
1535 	unsigned long flags;
1536 	struct serial_iso7816 aux;
1537 
1538 	if (!port->iso7816_config)
1539 		return -ENOTTY;
1540 
1541 	spin_lock_irqsave(&port->lock, flags);
1542 	aux = port->iso7816;
1543 	spin_unlock_irqrestore(&port->lock, flags);
1544 
1545 	if (copy_to_user(iso7816, &aux, sizeof(aux)))
1546 		return -EFAULT;
1547 
1548 	return 0;
1549 }
1550 
uart_set_iso7816_config(struct uart_port * port,struct serial_iso7816 __user * iso7816_user)1551 static int uart_set_iso7816_config(struct uart_port *port,
1552 				   struct serial_iso7816 __user *iso7816_user)
1553 {
1554 	struct serial_iso7816 iso7816;
1555 	int i, ret;
1556 	unsigned long flags;
1557 
1558 	if (!port->iso7816_config)
1559 		return -ENOTTY;
1560 
1561 	if (copy_from_user(&iso7816, iso7816_user, sizeof(*iso7816_user)))
1562 		return -EFAULT;
1563 
1564 	/*
1565 	 * There are 5 words reserved for future use. Check that userspace
1566 	 * doesn't put stuff in there to prevent breakages in the future.
1567 	 */
1568 	for (i = 0; i < ARRAY_SIZE(iso7816.reserved); i++)
1569 		if (iso7816.reserved[i])
1570 			return -EINVAL;
1571 
1572 	spin_lock_irqsave(&port->lock, flags);
1573 	ret = port->iso7816_config(port, &iso7816);
1574 	spin_unlock_irqrestore(&port->lock, flags);
1575 	if (ret)
1576 		return ret;
1577 
1578 	if (copy_to_user(iso7816_user, &port->iso7816, sizeof(port->iso7816)))
1579 		return -EFAULT;
1580 
1581 	return 0;
1582 }
1583 
1584 /*
1585  * Called via sys_ioctl.  We can use spin_lock_irq() here.
1586  */
1587 static int
uart_ioctl(struct tty_struct * tty,unsigned int cmd,unsigned long arg)1588 uart_ioctl(struct tty_struct *tty, unsigned int cmd, unsigned long arg)
1589 {
1590 	struct uart_state *state = tty->driver_data;
1591 	struct tty_port *port = &state->port;
1592 	struct uart_port *uport;
1593 	void __user *uarg = (void __user *)arg;
1594 	int ret = -ENOIOCTLCMD;
1595 
1596 
1597 	/*
1598 	 * These ioctls don't rely on the hardware to be present.
1599 	 */
1600 	switch (cmd) {
1601 	case TIOCSERCONFIG:
1602 		down_write(&tty->termios_rwsem);
1603 		ret = uart_do_autoconfig(tty, state);
1604 		up_write(&tty->termios_rwsem);
1605 		break;
1606 	}
1607 
1608 	if (ret != -ENOIOCTLCMD)
1609 		goto out;
1610 
1611 	if (tty_io_error(tty)) {
1612 		ret = -EIO;
1613 		goto out;
1614 	}
1615 
1616 	/*
1617 	 * The following should only be used when hardware is present.
1618 	 */
1619 	switch (cmd) {
1620 	case TIOCMIWAIT:
1621 		ret = uart_wait_modem_status(state, arg);
1622 		break;
1623 	}
1624 
1625 	if (ret != -ENOIOCTLCMD)
1626 		goto out;
1627 
1628 	/* rs485_config requires more locking than others */
1629 	if (cmd == TIOCSRS485)
1630 		down_write(&tty->termios_rwsem);
1631 
1632 	mutex_lock(&port->mutex);
1633 	uport = uart_port_check(state);
1634 
1635 	if (!uport || tty_io_error(tty)) {
1636 		ret = -EIO;
1637 		goto out_up;
1638 	}
1639 
1640 	/*
1641 	 * All these rely on hardware being present and need to be
1642 	 * protected against the tty being hung up.
1643 	 */
1644 
1645 	switch (cmd) {
1646 	case TIOCSERGETLSR: /* Get line status register */
1647 		ret = uart_get_lsr_info(tty, state, uarg);
1648 		break;
1649 
1650 	case TIOCGRS485:
1651 		ret = uart_get_rs485_config(uport, uarg);
1652 		break;
1653 
1654 	case TIOCSRS485:
1655 		ret = uart_set_rs485_config(tty, uport, uarg);
1656 		break;
1657 
1658 	case TIOCSISO7816:
1659 		ret = uart_set_iso7816_config(state->uart_port, uarg);
1660 		break;
1661 
1662 	case TIOCGISO7816:
1663 		ret = uart_get_iso7816_config(state->uart_port, uarg);
1664 		break;
1665 	default:
1666 		if (uport->ops->ioctl)
1667 			ret = uport->ops->ioctl(uport, cmd, arg);
1668 		break;
1669 	}
1670 out_up:
1671 	mutex_unlock(&port->mutex);
1672 	if (cmd == TIOCSRS485)
1673 		up_write(&tty->termios_rwsem);
1674 out:
1675 	return ret;
1676 }
1677 
uart_set_ldisc(struct tty_struct * tty)1678 static void uart_set_ldisc(struct tty_struct *tty)
1679 {
1680 	struct uart_state *state = tty->driver_data;
1681 	struct uart_port *uport;
1682 	struct tty_port *port = &state->port;
1683 
1684 	if (!tty_port_initialized(port))
1685 		return;
1686 
1687 	mutex_lock(&state->port.mutex);
1688 	uport = uart_port_check(state);
1689 	if (uport && uport->ops->set_ldisc)
1690 		uport->ops->set_ldisc(uport, &tty->termios);
1691 	mutex_unlock(&state->port.mutex);
1692 }
1693 
uart_set_termios(struct tty_struct * tty,const struct ktermios * old_termios)1694 static void uart_set_termios(struct tty_struct *tty,
1695 			     const struct ktermios *old_termios)
1696 {
1697 	struct uart_state *state = tty->driver_data;
1698 	struct uart_port *uport;
1699 	unsigned int cflag = tty->termios.c_cflag;
1700 	unsigned int iflag_mask = IGNBRK|BRKINT|IGNPAR|PARMRK|INPCK;
1701 	bool sw_changed = false;
1702 
1703 	mutex_lock(&state->port.mutex);
1704 	uport = uart_port_check(state);
1705 	if (!uport)
1706 		goto out;
1707 
1708 	/*
1709 	 * Drivers doing software flow control also need to know
1710 	 * about changes to these input settings.
1711 	 */
1712 	if (uport->flags & UPF_SOFT_FLOW) {
1713 		iflag_mask |= IXANY|IXON|IXOFF;
1714 		sw_changed =
1715 		   tty->termios.c_cc[VSTART] != old_termios->c_cc[VSTART] ||
1716 		   tty->termios.c_cc[VSTOP] != old_termios->c_cc[VSTOP];
1717 	}
1718 
1719 	/*
1720 	 * These are the bits that are used to setup various
1721 	 * flags in the low level driver. We can ignore the Bfoo
1722 	 * bits in c_cflag; c_[io]speed will always be set
1723 	 * appropriately by set_termios() in tty_ioctl.c
1724 	 */
1725 	if ((cflag ^ old_termios->c_cflag) == 0 &&
1726 	    tty->termios.c_ospeed == old_termios->c_ospeed &&
1727 	    tty->termios.c_ispeed == old_termios->c_ispeed &&
1728 	    ((tty->termios.c_iflag ^ old_termios->c_iflag) & iflag_mask) == 0 &&
1729 	    !sw_changed) {
1730 		goto out;
1731 	}
1732 
1733 	uart_change_line_settings(tty, state, old_termios);
1734 	/* reload cflag from termios; port driver may have overridden flags */
1735 	cflag = tty->termios.c_cflag;
1736 
1737 	/* Handle transition to B0 status */
1738 	if (((old_termios->c_cflag & CBAUD) != B0) && ((cflag & CBAUD) == B0))
1739 		uart_clear_mctrl(uport, TIOCM_RTS | TIOCM_DTR);
1740 	/* Handle transition away from B0 status */
1741 	else if (((old_termios->c_cflag & CBAUD) == B0) && ((cflag & CBAUD) != B0)) {
1742 		unsigned int mask = TIOCM_DTR;
1743 
1744 		if (!(cflag & CRTSCTS) || !tty_throttled(tty))
1745 			mask |= TIOCM_RTS;
1746 		uart_set_mctrl(uport, mask);
1747 	}
1748 out:
1749 	mutex_unlock(&state->port.mutex);
1750 }
1751 
1752 /*
1753  * Calls to uart_close() are serialised via the tty_lock in
1754  *   drivers/tty/tty_io.c:tty_release()
1755  *   drivers/tty/tty_io.c:do_tty_hangup()
1756  */
uart_close(struct tty_struct * tty,struct file * filp)1757 static void uart_close(struct tty_struct *tty, struct file *filp)
1758 {
1759 	struct uart_state *state = tty->driver_data;
1760 
1761 	if (!state) {
1762 		struct uart_driver *drv = tty->driver->driver_state;
1763 		struct tty_port *port;
1764 
1765 		state = drv->state + tty->index;
1766 		port = &state->port;
1767 		spin_lock_irq(&port->lock);
1768 		--port->count;
1769 		spin_unlock_irq(&port->lock);
1770 		return;
1771 	}
1772 
1773 	pr_debug("uart_close(%d) called\n", tty->index);
1774 
1775 	tty_port_close(tty->port, tty, filp);
1776 }
1777 
uart_tty_port_shutdown(struct tty_port * port)1778 static void uart_tty_port_shutdown(struct tty_port *port)
1779 {
1780 	struct uart_state *state = container_of(port, struct uart_state, port);
1781 	struct uart_port *uport = uart_port_check(state);
1782 	char *buf;
1783 
1784 	/*
1785 	 * At this point, we stop accepting input.  To do this, we
1786 	 * disable the receive line status interrupts.
1787 	 */
1788 	if (WARN(!uport, "detached port still initialized!\n"))
1789 		return;
1790 
1791 	spin_lock_irq(&uport->lock);
1792 	uport->ops->stop_rx(uport);
1793 	spin_unlock_irq(&uport->lock);
1794 
1795 	serial_base_port_shutdown(uport);
1796 	uart_port_shutdown(port);
1797 
1798 	/*
1799 	 * It's possible for shutdown to be called after suspend if we get
1800 	 * a DCD drop (hangup) at just the right time.  Clear suspended bit so
1801 	 * we don't try to resume a port that has been shutdown.
1802 	 */
1803 	tty_port_set_suspended(port, false);
1804 
1805 	/*
1806 	 * Free the transmit buffer.
1807 	 */
1808 	spin_lock_irq(&uport->lock);
1809 	uart_circ_clear(&state->xmit);
1810 	buf = state->xmit.buf;
1811 	state->xmit.buf = NULL;
1812 	spin_unlock_irq(&uport->lock);
1813 
1814 	free_page((unsigned long)buf);
1815 
1816 	uart_change_pm(state, UART_PM_STATE_OFF);
1817 }
1818 
uart_wait_until_sent(struct tty_struct * tty,int timeout)1819 static void uart_wait_until_sent(struct tty_struct *tty, int timeout)
1820 {
1821 	struct uart_state *state = tty->driver_data;
1822 	struct uart_port *port;
1823 	unsigned long char_time, expire, fifo_timeout;
1824 
1825 	port = uart_port_ref(state);
1826 	if (!port)
1827 		return;
1828 
1829 	if (port->type == PORT_UNKNOWN || port->fifosize == 0) {
1830 		uart_port_deref(port);
1831 		return;
1832 	}
1833 
1834 	/*
1835 	 * Set the check interval to be 1/5 of the estimated time to
1836 	 * send a single character, and make it at least 1.  The check
1837 	 * interval should also be less than the timeout.
1838 	 *
1839 	 * Note: we have to use pretty tight timings here to satisfy
1840 	 * the NIST-PCTS.
1841 	 */
1842 	char_time = max(nsecs_to_jiffies(port->frame_time / 5), 1UL);
1843 
1844 	if (timeout && timeout < char_time)
1845 		char_time = timeout;
1846 
1847 	if (!uart_cts_enabled(port)) {
1848 		/*
1849 		 * If the transmitter hasn't cleared in twice the approximate
1850 		 * amount of time to send the entire FIFO, it probably won't
1851 		 * ever clear.  This assumes the UART isn't doing flow
1852 		 * control, which is currently the case.  Hence, if it ever
1853 		 * takes longer than FIFO timeout, this is probably due to a
1854 		 * UART bug of some kind.  So, we clamp the timeout parameter at
1855 		 * 2 * FIFO timeout.
1856 		 */
1857 		fifo_timeout = uart_fifo_timeout(port);
1858 		if (timeout == 0 || timeout > 2 * fifo_timeout)
1859 			timeout = 2 * fifo_timeout;
1860 	}
1861 
1862 	expire = jiffies + timeout;
1863 
1864 	pr_debug("uart_wait_until_sent(%d), jiffies=%lu, expire=%lu...\n",
1865 		port->line, jiffies, expire);
1866 
1867 	/*
1868 	 * Check whether the transmitter is empty every 'char_time'.
1869 	 * 'timeout' / 'expire' give us the maximum amount of time
1870 	 * we wait.
1871 	 */
1872 	while (!port->ops->tx_empty(port)) {
1873 		msleep_interruptible(jiffies_to_msecs(char_time));
1874 		if (signal_pending(current))
1875 			break;
1876 		if (timeout && time_after(jiffies, expire))
1877 			break;
1878 	}
1879 	uart_port_deref(port);
1880 }
1881 
1882 /*
1883  * Calls to uart_hangup() are serialised by the tty_lock in
1884  *   drivers/tty/tty_io.c:do_tty_hangup()
1885  * This runs from a workqueue and can sleep for a _short_ time only.
1886  */
uart_hangup(struct tty_struct * tty)1887 static void uart_hangup(struct tty_struct *tty)
1888 {
1889 	struct uart_state *state = tty->driver_data;
1890 	struct tty_port *port = &state->port;
1891 	struct uart_port *uport;
1892 	unsigned long flags;
1893 
1894 	pr_debug("uart_hangup(%d)\n", tty->index);
1895 
1896 	mutex_lock(&port->mutex);
1897 	uport = uart_port_check(state);
1898 	WARN(!uport, "hangup of detached port!\n");
1899 
1900 	if (tty_port_active(port)) {
1901 		uart_flush_buffer(tty);
1902 		uart_shutdown(tty, state);
1903 		spin_lock_irqsave(&port->lock, flags);
1904 		port->count = 0;
1905 		spin_unlock_irqrestore(&port->lock, flags);
1906 		tty_port_set_active(port, false);
1907 		tty_port_tty_set(port, NULL);
1908 		if (uport && !uart_console(uport))
1909 			uart_change_pm(state, UART_PM_STATE_OFF);
1910 		wake_up_interruptible(&port->open_wait);
1911 		wake_up_interruptible(&port->delta_msr_wait);
1912 	}
1913 	mutex_unlock(&port->mutex);
1914 }
1915 
1916 /* uport == NULL if uart_port has already been removed */
uart_port_shutdown(struct tty_port * port)1917 static void uart_port_shutdown(struct tty_port *port)
1918 {
1919 	struct uart_state *state = container_of(port, struct uart_state, port);
1920 	struct uart_port *uport = uart_port_check(state);
1921 
1922 	/*
1923 	 * clear delta_msr_wait queue to avoid mem leaks: we may free
1924 	 * the irq here so the queue might never be woken up.  Note
1925 	 * that we won't end up waiting on delta_msr_wait again since
1926 	 * any outstanding file descriptors should be pointing at
1927 	 * hung_up_tty_fops now.
1928 	 */
1929 	wake_up_interruptible(&port->delta_msr_wait);
1930 
1931 	if (uport) {
1932 		/* Free the IRQ and disable the port. */
1933 		uport->ops->shutdown(uport);
1934 
1935 		/* Ensure that the IRQ handler isn't running on another CPU. */
1936 		synchronize_irq(uport->irq);
1937 	}
1938 }
1939 
uart_carrier_raised(struct tty_port * port)1940 static bool uart_carrier_raised(struct tty_port *port)
1941 {
1942 	struct uart_state *state = container_of(port, struct uart_state, port);
1943 	struct uart_port *uport;
1944 	int mctrl;
1945 
1946 	uport = uart_port_ref(state);
1947 	/*
1948 	 * Should never observe uport == NULL since checks for hangup should
1949 	 * abort the tty_port_block_til_ready() loop before checking for carrier
1950 	 * raised -- but report carrier raised if it does anyway so open will
1951 	 * continue and not sleep
1952 	 */
1953 	if (WARN_ON(!uport))
1954 		return true;
1955 	spin_lock_irq(&uport->lock);
1956 	uart_enable_ms(uport);
1957 	mctrl = uport->ops->get_mctrl(uport);
1958 	spin_unlock_irq(&uport->lock);
1959 	uart_port_deref(uport);
1960 
1961 	return mctrl & TIOCM_CAR;
1962 }
1963 
uart_dtr_rts(struct tty_port * port,bool active)1964 static void uart_dtr_rts(struct tty_port *port, bool active)
1965 {
1966 	struct uart_state *state = container_of(port, struct uart_state, port);
1967 	struct uart_port *uport;
1968 
1969 	uport = uart_port_ref(state);
1970 	if (!uport)
1971 		return;
1972 	uart_port_dtr_rts(uport, active);
1973 	uart_port_deref(uport);
1974 }
1975 
uart_install(struct tty_driver * driver,struct tty_struct * tty)1976 static int uart_install(struct tty_driver *driver, struct tty_struct *tty)
1977 {
1978 	struct uart_driver *drv = driver->driver_state;
1979 	struct uart_state *state = drv->state + tty->index;
1980 
1981 	tty->driver_data = state;
1982 
1983 	return tty_standard_install(driver, tty);
1984 }
1985 
1986 /*
1987  * Calls to uart_open are serialised by the tty_lock in
1988  *   drivers/tty/tty_io.c:tty_open()
1989  * Note that if this fails, then uart_close() _will_ be called.
1990  *
1991  * In time, we want to scrap the "opening nonpresent ports"
1992  * behaviour and implement an alternative way for setserial
1993  * to set base addresses/ports/types.  This will allow us to
1994  * get rid of a certain amount of extra tests.
1995  */
uart_open(struct tty_struct * tty,struct file * filp)1996 static int uart_open(struct tty_struct *tty, struct file *filp)
1997 {
1998 	struct uart_state *state = tty->driver_data;
1999 	int retval;
2000 
2001 	retval = tty_port_open(&state->port, tty, filp);
2002 	if (retval > 0)
2003 		retval = 0;
2004 
2005 	return retval;
2006 }
2007 
uart_port_activate(struct tty_port * port,struct tty_struct * tty)2008 static int uart_port_activate(struct tty_port *port, struct tty_struct *tty)
2009 {
2010 	struct uart_state *state = container_of(port, struct uart_state, port);
2011 	struct uart_port *uport;
2012 	int ret;
2013 
2014 	uport = uart_port_check(state);
2015 	if (!uport || uport->flags & UPF_DEAD)
2016 		return -ENXIO;
2017 
2018 	/*
2019 	 * Start up the serial port.
2020 	 */
2021 	ret = uart_startup(tty, state, false);
2022 	if (ret > 0)
2023 		tty_port_set_active(port, true);
2024 
2025 	return ret;
2026 }
2027 
uart_type(struct uart_port * port)2028 static const char *uart_type(struct uart_port *port)
2029 {
2030 	const char *str = NULL;
2031 
2032 	if (port->ops->type)
2033 		str = port->ops->type(port);
2034 
2035 	if (!str)
2036 		str = "unknown";
2037 
2038 	return str;
2039 }
2040 
2041 #ifdef CONFIG_PROC_FS
2042 
uart_line_info(struct seq_file * m,struct uart_driver * drv,int i)2043 static void uart_line_info(struct seq_file *m, struct uart_driver *drv, int i)
2044 {
2045 	struct uart_state *state = drv->state + i;
2046 	struct tty_port *port = &state->port;
2047 	enum uart_pm_state pm_state;
2048 	struct uart_port *uport;
2049 	char stat_buf[32];
2050 	unsigned int status;
2051 	int mmio;
2052 
2053 	mutex_lock(&port->mutex);
2054 	uport = uart_port_check(state);
2055 	if (!uport)
2056 		goto out;
2057 
2058 	mmio = uport->iotype >= UPIO_MEM;
2059 	seq_printf(m, "%d: uart:%s %s%08llX irq:%d",
2060 			uport->line, uart_type(uport),
2061 			mmio ? "mmio:0x" : "port:",
2062 			mmio ? (unsigned long long)uport->mapbase
2063 			     : (unsigned long long)uport->iobase,
2064 			uport->irq);
2065 
2066 	if (uport->type == PORT_UNKNOWN) {
2067 		seq_putc(m, '\n');
2068 		goto out;
2069 	}
2070 
2071 	if (capable(CAP_SYS_ADMIN)) {
2072 		pm_state = state->pm_state;
2073 		if (pm_state != UART_PM_STATE_ON)
2074 			uart_change_pm(state, UART_PM_STATE_ON);
2075 		spin_lock_irq(&uport->lock);
2076 		status = uport->ops->get_mctrl(uport);
2077 		spin_unlock_irq(&uport->lock);
2078 		if (pm_state != UART_PM_STATE_ON)
2079 			uart_change_pm(state, pm_state);
2080 
2081 		seq_printf(m, " tx:%d rx:%d",
2082 				uport->icount.tx, uport->icount.rx);
2083 		if (uport->icount.frame)
2084 			seq_printf(m, " fe:%d",	uport->icount.frame);
2085 		if (uport->icount.parity)
2086 			seq_printf(m, " pe:%d",	uport->icount.parity);
2087 		if (uport->icount.brk)
2088 			seq_printf(m, " brk:%d", uport->icount.brk);
2089 		if (uport->icount.overrun)
2090 			seq_printf(m, " oe:%d", uport->icount.overrun);
2091 		if (uport->icount.buf_overrun)
2092 			seq_printf(m, " bo:%d", uport->icount.buf_overrun);
2093 
2094 #define INFOBIT(bit, str) \
2095 	if (uport->mctrl & (bit)) \
2096 		strncat(stat_buf, (str), sizeof(stat_buf) - \
2097 			strlen(stat_buf) - 2)
2098 #define STATBIT(bit, str) \
2099 	if (status & (bit)) \
2100 		strncat(stat_buf, (str), sizeof(stat_buf) - \
2101 		       strlen(stat_buf) - 2)
2102 
2103 		stat_buf[0] = '\0';
2104 		stat_buf[1] = '\0';
2105 		INFOBIT(TIOCM_RTS, "|RTS");
2106 		STATBIT(TIOCM_CTS, "|CTS");
2107 		INFOBIT(TIOCM_DTR, "|DTR");
2108 		STATBIT(TIOCM_DSR, "|DSR");
2109 		STATBIT(TIOCM_CAR, "|CD");
2110 		STATBIT(TIOCM_RNG, "|RI");
2111 		if (stat_buf[0])
2112 			stat_buf[0] = ' ';
2113 
2114 		seq_puts(m, stat_buf);
2115 	}
2116 	seq_putc(m, '\n');
2117 #undef STATBIT
2118 #undef INFOBIT
2119 out:
2120 	mutex_unlock(&port->mutex);
2121 }
2122 
uart_proc_show(struct seq_file * m,void * v)2123 static int uart_proc_show(struct seq_file *m, void *v)
2124 {
2125 	struct tty_driver *ttydrv = m->private;
2126 	struct uart_driver *drv = ttydrv->driver_state;
2127 	int i;
2128 
2129 	seq_printf(m, "serinfo:1.0 driver%s%s revision:%s\n", "", "", "");
2130 	for (i = 0; i < drv->nr; i++)
2131 		uart_line_info(m, drv, i);
2132 	return 0;
2133 }
2134 #endif
2135 
uart_port_spin_lock_init(struct uart_port * port)2136 static void uart_port_spin_lock_init(struct uart_port *port)
2137 {
2138 	spin_lock_init(&port->lock);
2139 	lockdep_set_class(&port->lock, &port_lock_key);
2140 }
2141 
2142 #if defined(CONFIG_SERIAL_CORE_CONSOLE) || defined(CONFIG_CONSOLE_POLL)
2143 /**
2144  * uart_console_write - write a console message to a serial port
2145  * @port: the port to write the message
2146  * @s: array of characters
2147  * @count: number of characters in string to write
2148  * @putchar: function to write character to port
2149  */
uart_console_write(struct uart_port * port,const char * s,unsigned int count,void (* putchar)(struct uart_port *,unsigned char))2150 void uart_console_write(struct uart_port *port, const char *s,
2151 			unsigned int count,
2152 			void (*putchar)(struct uart_port *, unsigned char))
2153 {
2154 	unsigned int i;
2155 
2156 	for (i = 0; i < count; i++, s++) {
2157 		if (*s == '\n')
2158 			putchar(port, '\r');
2159 		putchar(port, *s);
2160 	}
2161 }
2162 EXPORT_SYMBOL_GPL(uart_console_write);
2163 
2164 /**
2165  * uart_get_console - get uart port for console
2166  * @ports: ports to search in
2167  * @nr: number of @ports
2168  * @co: console to search for
2169  * Returns: uart_port for the console @co
2170  *
2171  * Check whether an invalid uart number has been specified (as @co->index), and
2172  * if so, search for the first available port that does have console support.
2173  */
2174 struct uart_port * __init
uart_get_console(struct uart_port * ports,int nr,struct console * co)2175 uart_get_console(struct uart_port *ports, int nr, struct console *co)
2176 {
2177 	int idx = co->index;
2178 
2179 	if (idx < 0 || idx >= nr || (ports[idx].iobase == 0 &&
2180 				     ports[idx].membase == NULL))
2181 		for (idx = 0; idx < nr; idx++)
2182 			if (ports[idx].iobase != 0 ||
2183 			    ports[idx].membase != NULL)
2184 				break;
2185 
2186 	co->index = idx;
2187 
2188 	return ports + idx;
2189 }
2190 
2191 /**
2192  * uart_parse_earlycon - Parse earlycon options
2193  * @p:	     ptr to 2nd field (ie., just beyond '<name>,')
2194  * @iotype:  ptr for decoded iotype (out)
2195  * @addr:    ptr for decoded mapbase/iobase (out)
2196  * @options: ptr for <options> field; %NULL if not present (out)
2197  *
2198  * Decodes earlycon kernel command line parameters of the form:
2199  *  * earlycon=<name>,io|mmio|mmio16|mmio32|mmio32be|mmio32native,<addr>,<options>
2200  *  * console=<name>,io|mmio|mmio16|mmio32|mmio32be|mmio32native,<addr>,<options>
2201  *
2202  * The optional form:
2203  *  * earlycon=<name>,0x<addr>,<options>
2204  *  * console=<name>,0x<addr>,<options>
2205  *
2206  * is also accepted; the returned @iotype will be %UPIO_MEM.
2207  *
2208  * Returns: 0 on success or -%EINVAL on failure
2209  */
uart_parse_earlycon(char * p,unsigned char * iotype,resource_size_t * addr,char ** options)2210 int uart_parse_earlycon(char *p, unsigned char *iotype, resource_size_t *addr,
2211 			char **options)
2212 {
2213 	if (strncmp(p, "mmio,", 5) == 0) {
2214 		*iotype = UPIO_MEM;
2215 		p += 5;
2216 	} else if (strncmp(p, "mmio16,", 7) == 0) {
2217 		*iotype = UPIO_MEM16;
2218 		p += 7;
2219 	} else if (strncmp(p, "mmio32,", 7) == 0) {
2220 		*iotype = UPIO_MEM32;
2221 		p += 7;
2222 	} else if (strncmp(p, "mmio32be,", 9) == 0) {
2223 		*iotype = UPIO_MEM32BE;
2224 		p += 9;
2225 	} else if (strncmp(p, "mmio32native,", 13) == 0) {
2226 		*iotype = IS_ENABLED(CONFIG_CPU_BIG_ENDIAN) ?
2227 			UPIO_MEM32BE : UPIO_MEM32;
2228 		p += 13;
2229 	} else if (strncmp(p, "io,", 3) == 0) {
2230 		*iotype = UPIO_PORT;
2231 		p += 3;
2232 	} else if (strncmp(p, "0x", 2) == 0) {
2233 		*iotype = UPIO_MEM;
2234 	} else {
2235 		return -EINVAL;
2236 	}
2237 
2238 	/*
2239 	 * Before you replace it with kstrtoull(), think about options separator
2240 	 * (',') it will not tolerate
2241 	 */
2242 	*addr = simple_strtoull(p, NULL, 0);
2243 	p = strchr(p, ',');
2244 	if (p)
2245 		p++;
2246 
2247 	*options = p;
2248 	return 0;
2249 }
2250 EXPORT_SYMBOL_GPL(uart_parse_earlycon);
2251 
2252 /**
2253  * uart_parse_options - Parse serial port baud/parity/bits/flow control.
2254  * @options: pointer to option string
2255  * @baud: pointer to an 'int' variable for the baud rate.
2256  * @parity: pointer to an 'int' variable for the parity.
2257  * @bits: pointer to an 'int' variable for the number of data bits.
2258  * @flow: pointer to an 'int' variable for the flow control character.
2259  *
2260  * uart_parse_options() decodes a string containing the serial console
2261  * options. The format of the string is <baud><parity><bits><flow>,
2262  * eg: 115200n8r
2263  */
2264 void
uart_parse_options(const char * options,int * baud,int * parity,int * bits,int * flow)2265 uart_parse_options(const char *options, int *baud, int *parity,
2266 		   int *bits, int *flow)
2267 {
2268 	const char *s = options;
2269 
2270 	*baud = simple_strtoul(s, NULL, 10);
2271 	while (*s >= '0' && *s <= '9')
2272 		s++;
2273 	if (*s)
2274 		*parity = *s++;
2275 	if (*s)
2276 		*bits = *s++ - '0';
2277 	if (*s)
2278 		*flow = *s;
2279 }
2280 EXPORT_SYMBOL_GPL(uart_parse_options);
2281 
2282 /**
2283  * uart_set_options - setup the serial console parameters
2284  * @port: pointer to the serial ports uart_port structure
2285  * @co: console pointer
2286  * @baud: baud rate
2287  * @parity: parity character - 'n' (none), 'o' (odd), 'e' (even)
2288  * @bits: number of data bits
2289  * @flow: flow control character - 'r' (rts)
2290  *
2291  * Locking: Caller must hold console_list_lock in order to serialize
2292  * early initialization of the serial-console lock.
2293  */
2294 int
uart_set_options(struct uart_port * port,struct console * co,int baud,int parity,int bits,int flow)2295 uart_set_options(struct uart_port *port, struct console *co,
2296 		 int baud, int parity, int bits, int flow)
2297 {
2298 	struct ktermios termios;
2299 	static struct ktermios dummy;
2300 
2301 	/*
2302 	 * Ensure that the serial-console lock is initialised early.
2303 	 *
2304 	 * Note that the console-registered check is needed because
2305 	 * kgdboc can call uart_set_options() for an already registered
2306 	 * console via tty_find_polling_driver() and uart_poll_init().
2307 	 */
2308 	if (!uart_console_registered_locked(port) && !port->console_reinit)
2309 		uart_port_spin_lock_init(port);
2310 
2311 	memset(&termios, 0, sizeof(struct ktermios));
2312 
2313 	termios.c_cflag |= CREAD | HUPCL | CLOCAL;
2314 	tty_termios_encode_baud_rate(&termios, baud, baud);
2315 
2316 	if (bits == 7)
2317 		termios.c_cflag |= CS7;
2318 	else
2319 		termios.c_cflag |= CS8;
2320 
2321 	switch (parity) {
2322 	case 'o': case 'O':
2323 		termios.c_cflag |= PARODD;
2324 		fallthrough;
2325 	case 'e': case 'E':
2326 		termios.c_cflag |= PARENB;
2327 		break;
2328 	}
2329 
2330 	if (flow == 'r')
2331 		termios.c_cflag |= CRTSCTS;
2332 
2333 	/*
2334 	 * some uarts on other side don't support no flow control.
2335 	 * So we set * DTR in host uart to make them happy
2336 	 */
2337 	port->mctrl |= TIOCM_DTR;
2338 
2339 	port->ops->set_termios(port, &termios, &dummy);
2340 	/*
2341 	 * Allow the setting of the UART parameters with a NULL console
2342 	 * too:
2343 	 */
2344 	if (co) {
2345 		co->cflag = termios.c_cflag;
2346 		co->ispeed = termios.c_ispeed;
2347 		co->ospeed = termios.c_ospeed;
2348 	}
2349 
2350 	return 0;
2351 }
2352 EXPORT_SYMBOL_GPL(uart_set_options);
2353 #endif /* CONFIG_SERIAL_CORE_CONSOLE */
2354 
2355 /**
2356  * uart_change_pm - set power state of the port
2357  *
2358  * @state: port descriptor
2359  * @pm_state: new state
2360  *
2361  * Locking: port->mutex has to be held
2362  */
uart_change_pm(struct uart_state * state,enum uart_pm_state pm_state)2363 static void uart_change_pm(struct uart_state *state,
2364 			   enum uart_pm_state pm_state)
2365 {
2366 	struct uart_port *port = uart_port_check(state);
2367 
2368 	if (state->pm_state != pm_state) {
2369 		if (port && port->ops->pm)
2370 			port->ops->pm(port, pm_state, state->pm_state);
2371 		state->pm_state = pm_state;
2372 	}
2373 }
2374 
2375 struct uart_match {
2376 	struct uart_port *port;
2377 	struct uart_driver *driver;
2378 };
2379 
serial_match_port(struct device * dev,void * data)2380 static int serial_match_port(struct device *dev, void *data)
2381 {
2382 	struct uart_match *match = data;
2383 	struct tty_driver *tty_drv = match->driver->tty_driver;
2384 	dev_t devt = MKDEV(tty_drv->major, tty_drv->minor_start) +
2385 		match->port->line;
2386 
2387 	return dev->devt == devt; /* Actually, only one tty per port */
2388 }
2389 
uart_suspend_port(struct uart_driver * drv,struct uart_port * uport)2390 int uart_suspend_port(struct uart_driver *drv, struct uart_port *uport)
2391 {
2392 	struct uart_state *state = drv->state + uport->line;
2393 	struct tty_port *port = &state->port;
2394 	struct device *tty_dev;
2395 	struct uart_match match = {uport, drv};
2396 
2397 	mutex_lock(&port->mutex);
2398 
2399 	tty_dev = device_find_child(uport->dev, &match, serial_match_port);
2400 	if (tty_dev && device_may_wakeup(tty_dev)) {
2401 		enable_irq_wake(uport->irq);
2402 		put_device(tty_dev);
2403 		mutex_unlock(&port->mutex);
2404 		return 0;
2405 	}
2406 	put_device(tty_dev);
2407 
2408 	/*
2409 	 * Nothing to do if the console is not suspending
2410 	 * except stop_rx to prevent any asynchronous data
2411 	 * over RX line. However ensure that we will be
2412 	 * able to Re-start_rx later.
2413 	 */
2414 	if (!console_suspend_enabled && uart_console(uport)) {
2415 		if (uport->ops->start_rx) {
2416 			spin_lock_irq(&uport->lock);
2417 			uport->ops->stop_rx(uport);
2418 			spin_unlock_irq(&uport->lock);
2419 		}
2420 		goto unlock;
2421 	}
2422 
2423 	uport->suspended = 1;
2424 
2425 	if (tty_port_initialized(port)) {
2426 		const struct uart_ops *ops = uport->ops;
2427 		int tries;
2428 		unsigned int mctrl;
2429 
2430 		tty_port_set_suspended(port, true);
2431 		tty_port_set_initialized(port, false);
2432 
2433 		spin_lock_irq(&uport->lock);
2434 		ops->stop_tx(uport);
2435 		if (!(uport->rs485.flags & SER_RS485_ENABLED))
2436 			ops->set_mctrl(uport, 0);
2437 		/* save mctrl so it can be restored on resume */
2438 		mctrl = uport->mctrl;
2439 		uport->mctrl = 0;
2440 		ops->stop_rx(uport);
2441 		spin_unlock_irq(&uport->lock);
2442 
2443 		/*
2444 		 * Wait for the transmitter to empty.
2445 		 */
2446 		for (tries = 3; !ops->tx_empty(uport) && tries; tries--)
2447 			msleep(10);
2448 		if (!tries)
2449 			dev_err(uport->dev, "%s: Unable to drain transmitter\n",
2450 				uport->name);
2451 
2452 		ops->shutdown(uport);
2453 		uport->mctrl = mctrl;
2454 	}
2455 
2456 	/*
2457 	 * Disable the console device before suspending.
2458 	 */
2459 	if (uart_console(uport))
2460 		console_stop(uport->cons);
2461 
2462 	uart_change_pm(state, UART_PM_STATE_OFF);
2463 unlock:
2464 	mutex_unlock(&port->mutex);
2465 
2466 	return 0;
2467 }
2468 EXPORT_SYMBOL(uart_suspend_port);
2469 
uart_resume_port(struct uart_driver * drv,struct uart_port * uport)2470 int uart_resume_port(struct uart_driver *drv, struct uart_port *uport)
2471 {
2472 	struct uart_state *state = drv->state + uport->line;
2473 	struct tty_port *port = &state->port;
2474 	struct device *tty_dev;
2475 	struct uart_match match = {uport, drv};
2476 	struct ktermios termios;
2477 
2478 	mutex_lock(&port->mutex);
2479 
2480 	tty_dev = device_find_child(uport->dev, &match, serial_match_port);
2481 	if (!uport->suspended && device_may_wakeup(tty_dev)) {
2482 		if (irqd_is_wakeup_set(irq_get_irq_data((uport->irq))))
2483 			disable_irq_wake(uport->irq);
2484 		put_device(tty_dev);
2485 		mutex_unlock(&port->mutex);
2486 		return 0;
2487 	}
2488 	put_device(tty_dev);
2489 	uport->suspended = 0;
2490 
2491 	/*
2492 	 * Re-enable the console device after suspending.
2493 	 */
2494 	if (uart_console(uport)) {
2495 		/*
2496 		 * First try to use the console cflag setting.
2497 		 */
2498 		memset(&termios, 0, sizeof(struct ktermios));
2499 		termios.c_cflag = uport->cons->cflag;
2500 		termios.c_ispeed = uport->cons->ispeed;
2501 		termios.c_ospeed = uport->cons->ospeed;
2502 
2503 		/*
2504 		 * If that's unset, use the tty termios setting.
2505 		 */
2506 		if (port->tty && termios.c_cflag == 0)
2507 			termios = port->tty->termios;
2508 
2509 		if (console_suspend_enabled)
2510 			uart_change_pm(state, UART_PM_STATE_ON);
2511 		uport->ops->set_termios(uport, &termios, NULL);
2512 		if (!console_suspend_enabled && uport->ops->start_rx) {
2513 			spin_lock_irq(&uport->lock);
2514 			uport->ops->start_rx(uport);
2515 			spin_unlock_irq(&uport->lock);
2516 		}
2517 		if (console_suspend_enabled)
2518 			console_start(uport->cons);
2519 	}
2520 
2521 	if (tty_port_suspended(port)) {
2522 		const struct uart_ops *ops = uport->ops;
2523 		int ret;
2524 
2525 		uart_change_pm(state, UART_PM_STATE_ON);
2526 		spin_lock_irq(&uport->lock);
2527 		if (!(uport->rs485.flags & SER_RS485_ENABLED))
2528 			ops->set_mctrl(uport, 0);
2529 		spin_unlock_irq(&uport->lock);
2530 		if (console_suspend_enabled || !uart_console(uport)) {
2531 			/* Protected by port mutex for now */
2532 			struct tty_struct *tty = port->tty;
2533 
2534 			ret = ops->startup(uport);
2535 			if (ret == 0) {
2536 				if (tty)
2537 					uart_change_line_settings(tty, state, NULL);
2538 				uart_rs485_config(uport);
2539 				spin_lock_irq(&uport->lock);
2540 				if (!(uport->rs485.flags & SER_RS485_ENABLED))
2541 					ops->set_mctrl(uport, uport->mctrl);
2542 				ops->start_tx(uport);
2543 				spin_unlock_irq(&uport->lock);
2544 				tty_port_set_initialized(port, true);
2545 			} else {
2546 				/*
2547 				 * Failed to resume - maybe hardware went away?
2548 				 * Clear the "initialized" flag so we won't try
2549 				 * to call the low level drivers shutdown method.
2550 				 */
2551 				uart_shutdown(tty, state);
2552 			}
2553 		}
2554 
2555 		tty_port_set_suspended(port, false);
2556 	}
2557 
2558 	mutex_unlock(&port->mutex);
2559 
2560 	return 0;
2561 }
2562 EXPORT_SYMBOL(uart_resume_port);
2563 
2564 static inline void
uart_report_port(struct uart_driver * drv,struct uart_port * port)2565 uart_report_port(struct uart_driver *drv, struct uart_port *port)
2566 {
2567 	char address[64];
2568 
2569 	switch (port->iotype) {
2570 	case UPIO_PORT:
2571 		snprintf(address, sizeof(address), "I/O 0x%lx", port->iobase);
2572 		break;
2573 	case UPIO_HUB6:
2574 		snprintf(address, sizeof(address),
2575 			 "I/O 0x%lx offset 0x%x", port->iobase, port->hub6);
2576 		break;
2577 	case UPIO_MEM:
2578 	case UPIO_MEM16:
2579 	case UPIO_MEM32:
2580 	case UPIO_MEM32BE:
2581 	case UPIO_AU:
2582 	case UPIO_TSI:
2583 		snprintf(address, sizeof(address),
2584 			 "MMIO 0x%llx", (unsigned long long)port->mapbase);
2585 		break;
2586 	default:
2587 		strscpy(address, "*unknown*", sizeof(address));
2588 		break;
2589 	}
2590 
2591 	pr_info("%s%s%s at %s (irq = %d, base_baud = %d) is a %s\n",
2592 	       port->dev ? dev_name(port->dev) : "",
2593 	       port->dev ? ": " : "",
2594 	       port->name,
2595 	       address, port->irq, port->uartclk / 16, uart_type(port));
2596 
2597 	/* The magic multiplier feature is a bit obscure, so report it too.  */
2598 	if (port->flags & UPF_MAGIC_MULTIPLIER)
2599 		pr_info("%s%s%s extra baud rates supported: %d, %d",
2600 			port->dev ? dev_name(port->dev) : "",
2601 			port->dev ? ": " : "",
2602 			port->name,
2603 			port->uartclk / 8, port->uartclk / 4);
2604 }
2605 
2606 static void
uart_configure_port(struct uart_driver * drv,struct uart_state * state,struct uart_port * port)2607 uart_configure_port(struct uart_driver *drv, struct uart_state *state,
2608 		    struct uart_port *port)
2609 {
2610 	unsigned int flags;
2611 
2612 	/*
2613 	 * If there isn't a port here, don't do anything further.
2614 	 */
2615 	if (!port->iobase && !port->mapbase && !port->membase)
2616 		return;
2617 
2618 	/*
2619 	 * Now do the auto configuration stuff.  Note that config_port
2620 	 * is expected to claim the resources and map the port for us.
2621 	 */
2622 	flags = 0;
2623 	if (port->flags & UPF_AUTO_IRQ)
2624 		flags |= UART_CONFIG_IRQ;
2625 	if (port->flags & UPF_BOOT_AUTOCONF) {
2626 		if (!(port->flags & UPF_FIXED_TYPE)) {
2627 			port->type = PORT_UNKNOWN;
2628 			flags |= UART_CONFIG_TYPE;
2629 		}
2630 		/* Synchronize with possible boot console. */
2631 		if (uart_console(port))
2632 			console_lock();
2633 		port->ops->config_port(port, flags);
2634 		if (uart_console(port))
2635 			console_unlock();
2636 	}
2637 
2638 	if (port->type != PORT_UNKNOWN) {
2639 		unsigned long flags;
2640 
2641 		uart_report_port(drv, port);
2642 
2643 		/* Synchronize with possible boot console. */
2644 		if (uart_console(port))
2645 			console_lock();
2646 
2647 		/* Power up port for set_mctrl() */
2648 		uart_change_pm(state, UART_PM_STATE_ON);
2649 
2650 		/*
2651 		 * Ensure that the modem control lines are de-activated.
2652 		 * keep the DTR setting that is set in uart_set_options()
2653 		 * We probably don't need a spinlock around this, but
2654 		 */
2655 		spin_lock_irqsave(&port->lock, flags);
2656 		port->mctrl &= TIOCM_DTR;
2657 		if (!(port->rs485.flags & SER_RS485_ENABLED))
2658 			port->ops->set_mctrl(port, port->mctrl);
2659 		spin_unlock_irqrestore(&port->lock, flags);
2660 
2661 		uart_rs485_config(port);
2662 
2663 		if (uart_console(port))
2664 			console_unlock();
2665 
2666 		/*
2667 		 * If this driver supports console, and it hasn't been
2668 		 * successfully registered yet, try to re-register it.
2669 		 * It may be that the port was not available.
2670 		 */
2671 		if (port->cons && !console_is_registered(port->cons))
2672 			register_console(port->cons);
2673 
2674 		/*
2675 		 * Power down all ports by default, except the
2676 		 * console if we have one.
2677 		 */
2678 		if (!uart_console(port))
2679 			uart_change_pm(state, UART_PM_STATE_OFF);
2680 	}
2681 }
2682 
2683 #ifdef CONFIG_CONSOLE_POLL
2684 
uart_poll_init(struct tty_driver * driver,int line,char * options)2685 static int uart_poll_init(struct tty_driver *driver, int line, char *options)
2686 {
2687 	struct uart_driver *drv = driver->driver_state;
2688 	struct uart_state *state = drv->state + line;
2689 	enum uart_pm_state pm_state;
2690 	struct tty_port *tport;
2691 	struct uart_port *port;
2692 	int baud = 9600;
2693 	int bits = 8;
2694 	int parity = 'n';
2695 	int flow = 'n';
2696 	int ret = 0;
2697 
2698 	tport = &state->port;
2699 
2700 	guard(mutex)(&tport->mutex);
2701 
2702 	port = uart_port_check(state);
2703 	if (!port || port->type == PORT_UNKNOWN ||
2704 	    !(port->ops->poll_get_char && port->ops->poll_put_char))
2705 		return -1;
2706 
2707 	pm_state = state->pm_state;
2708 	uart_change_pm(state, UART_PM_STATE_ON);
2709 
2710 	if (port->ops->poll_init) {
2711 		/*
2712 		 * We don't set initialized as we only initialized the hw,
2713 		 * e.g. state->xmit is still uninitialized.
2714 		 */
2715 		if (!tty_port_initialized(tport))
2716 			ret = port->ops->poll_init(port);
2717 	}
2718 
2719 	if (!ret && options) {
2720 		uart_parse_options(options, &baud, &parity, &bits, &flow);
2721 		console_list_lock();
2722 		ret = uart_set_options(port, NULL, baud, parity, bits, flow);
2723 		console_list_unlock();
2724 	}
2725 
2726 	if (ret)
2727 		uart_change_pm(state, pm_state);
2728 
2729 	return ret;
2730 }
2731 
uart_poll_get_char(struct tty_driver * driver,int line)2732 static int uart_poll_get_char(struct tty_driver *driver, int line)
2733 {
2734 	struct uart_driver *drv = driver->driver_state;
2735 	struct uart_state *state = drv->state + line;
2736 	struct uart_port *port;
2737 	int ret = -1;
2738 
2739 	port = uart_port_ref(state);
2740 	if (port) {
2741 		ret = port->ops->poll_get_char(port);
2742 		uart_port_deref(port);
2743 	}
2744 
2745 	return ret;
2746 }
2747 
uart_poll_put_char(struct tty_driver * driver,int line,char ch)2748 static void uart_poll_put_char(struct tty_driver *driver, int line, char ch)
2749 {
2750 	struct uart_driver *drv = driver->driver_state;
2751 	struct uart_state *state = drv->state + line;
2752 	struct uart_port *port;
2753 
2754 	port = uart_port_ref(state);
2755 	if (!port)
2756 		return;
2757 
2758 	if (ch == '\n')
2759 		port->ops->poll_put_char(port, '\r');
2760 	port->ops->poll_put_char(port, ch);
2761 	uart_port_deref(port);
2762 }
2763 #endif
2764 
2765 static const struct tty_operations uart_ops = {
2766 	.install	= uart_install,
2767 	.open		= uart_open,
2768 	.close		= uart_close,
2769 	.write		= uart_write,
2770 	.put_char	= uart_put_char,
2771 	.flush_chars	= uart_flush_chars,
2772 	.write_room	= uart_write_room,
2773 	.chars_in_buffer= uart_chars_in_buffer,
2774 	.flush_buffer	= uart_flush_buffer,
2775 	.ioctl		= uart_ioctl,
2776 	.throttle	= uart_throttle,
2777 	.unthrottle	= uart_unthrottle,
2778 	.send_xchar	= uart_send_xchar,
2779 	.set_termios	= uart_set_termios,
2780 	.set_ldisc	= uart_set_ldisc,
2781 	.stop		= uart_stop,
2782 	.start		= uart_start,
2783 	.hangup		= uart_hangup,
2784 	.break_ctl	= uart_break_ctl,
2785 	.wait_until_sent= uart_wait_until_sent,
2786 #ifdef CONFIG_PROC_FS
2787 	.proc_show	= uart_proc_show,
2788 #endif
2789 	.tiocmget	= uart_tiocmget,
2790 	.tiocmset	= uart_tiocmset,
2791 	.set_serial	= uart_set_info_user,
2792 	.get_serial	= uart_get_info_user,
2793 	.get_icount	= uart_get_icount,
2794 #ifdef CONFIG_CONSOLE_POLL
2795 	.poll_init	= uart_poll_init,
2796 	.poll_get_char	= uart_poll_get_char,
2797 	.poll_put_char	= uart_poll_put_char,
2798 #endif
2799 };
2800 
2801 static const struct tty_port_operations uart_port_ops = {
2802 	.carrier_raised = uart_carrier_raised,
2803 	.dtr_rts	= uart_dtr_rts,
2804 	.activate	= uart_port_activate,
2805 	.shutdown	= uart_tty_port_shutdown,
2806 };
2807 
2808 /**
2809  * uart_register_driver - register a driver with the uart core layer
2810  * @drv: low level driver structure
2811  *
2812  * Register a uart driver with the core driver. We in turn register with the
2813  * tty layer, and initialise the core driver per-port state.
2814  *
2815  * We have a proc file in /proc/tty/driver which is named after the normal
2816  * driver.
2817  *
2818  * @drv->port should be %NULL, and the per-port structures should be registered
2819  * using uart_add_one_port() after this call has succeeded.
2820  *
2821  * Locking: none, Interrupts: enabled
2822  */
uart_register_driver(struct uart_driver * drv)2823 int uart_register_driver(struct uart_driver *drv)
2824 {
2825 	struct tty_driver *normal;
2826 	int i, retval = -ENOMEM;
2827 
2828 	BUG_ON(drv->state);
2829 
2830 	/*
2831 	 * Maybe we should be using a slab cache for this, especially if
2832 	 * we have a large number of ports to handle.
2833 	 */
2834 	drv->state = kcalloc(drv->nr, sizeof(struct uart_state), GFP_KERNEL);
2835 	if (!drv->state)
2836 		goto out;
2837 
2838 	normal = tty_alloc_driver(drv->nr, TTY_DRIVER_REAL_RAW |
2839 			TTY_DRIVER_DYNAMIC_DEV);
2840 	if (IS_ERR(normal)) {
2841 		retval = PTR_ERR(normal);
2842 		goto out_kfree;
2843 	}
2844 
2845 	drv->tty_driver = normal;
2846 
2847 	normal->driver_name	= drv->driver_name;
2848 	normal->name		= drv->dev_name;
2849 	normal->major		= drv->major;
2850 	normal->minor_start	= drv->minor;
2851 	normal->type		= TTY_DRIVER_TYPE_SERIAL;
2852 	normal->subtype		= SERIAL_TYPE_NORMAL;
2853 	normal->init_termios	= tty_std_termios;
2854 	normal->init_termios.c_cflag = B9600 | CS8 | CREAD | HUPCL | CLOCAL;
2855 	normal->init_termios.c_ispeed = normal->init_termios.c_ospeed = 9600;
2856 	normal->driver_state    = drv;
2857 	tty_set_operations(normal, &uart_ops);
2858 
2859 	/*
2860 	 * Initialise the UART state(s).
2861 	 */
2862 	for (i = 0; i < drv->nr; i++) {
2863 		struct uart_state *state = drv->state + i;
2864 		struct tty_port *port = &state->port;
2865 
2866 		tty_port_init(port);
2867 		port->ops = &uart_port_ops;
2868 	}
2869 
2870 	retval = tty_register_driver(normal);
2871 	if (retval >= 0)
2872 		return retval;
2873 
2874 	for (i = 0; i < drv->nr; i++)
2875 		tty_port_destroy(&drv->state[i].port);
2876 	tty_driver_kref_put(normal);
2877 out_kfree:
2878 	kfree(drv->state);
2879 out:
2880 	return retval;
2881 }
2882 EXPORT_SYMBOL(uart_register_driver);
2883 
2884 /**
2885  * uart_unregister_driver - remove a driver from the uart core layer
2886  * @drv: low level driver structure
2887  *
2888  * Remove all references to a driver from the core driver. The low level
2889  * driver must have removed all its ports via the uart_remove_one_port() if it
2890  * registered them with uart_add_one_port(). (I.e. @drv->port is %NULL.)
2891  *
2892  * Locking: none, Interrupts: enabled
2893  */
uart_unregister_driver(struct uart_driver * drv)2894 void uart_unregister_driver(struct uart_driver *drv)
2895 {
2896 	struct tty_driver *p = drv->tty_driver;
2897 	unsigned int i;
2898 
2899 	tty_unregister_driver(p);
2900 	tty_driver_kref_put(p);
2901 	for (i = 0; i < drv->nr; i++)
2902 		tty_port_destroy(&drv->state[i].port);
2903 	kfree(drv->state);
2904 	drv->state = NULL;
2905 	drv->tty_driver = NULL;
2906 }
2907 EXPORT_SYMBOL(uart_unregister_driver);
2908 
uart_console_device(struct console * co,int * index)2909 struct tty_driver *uart_console_device(struct console *co, int *index)
2910 {
2911 	struct uart_driver *p = co->data;
2912 	*index = co->index;
2913 	return p->tty_driver;
2914 }
2915 EXPORT_SYMBOL_GPL(uart_console_device);
2916 
uartclk_show(struct device * dev,struct device_attribute * attr,char * buf)2917 static ssize_t uartclk_show(struct device *dev,
2918 	struct device_attribute *attr, char *buf)
2919 {
2920 	struct serial_struct tmp;
2921 	struct tty_port *port = dev_get_drvdata(dev);
2922 
2923 	uart_get_info(port, &tmp);
2924 	return sprintf(buf, "%d\n", tmp.baud_base * 16);
2925 }
2926 
type_show(struct device * dev,struct device_attribute * attr,char * buf)2927 static ssize_t type_show(struct device *dev,
2928 	struct device_attribute *attr, char *buf)
2929 {
2930 	struct serial_struct tmp;
2931 	struct tty_port *port = dev_get_drvdata(dev);
2932 
2933 	uart_get_info(port, &tmp);
2934 	return sprintf(buf, "%d\n", tmp.type);
2935 }
2936 
line_show(struct device * dev,struct device_attribute * attr,char * buf)2937 static ssize_t line_show(struct device *dev,
2938 	struct device_attribute *attr, char *buf)
2939 {
2940 	struct serial_struct tmp;
2941 	struct tty_port *port = dev_get_drvdata(dev);
2942 
2943 	uart_get_info(port, &tmp);
2944 	return sprintf(buf, "%d\n", tmp.line);
2945 }
2946 
port_show(struct device * dev,struct device_attribute * attr,char * buf)2947 static ssize_t port_show(struct device *dev,
2948 	struct device_attribute *attr, char *buf)
2949 {
2950 	struct serial_struct tmp;
2951 	struct tty_port *port = dev_get_drvdata(dev);
2952 	unsigned long ioaddr;
2953 
2954 	uart_get_info(port, &tmp);
2955 	ioaddr = tmp.port;
2956 	if (HIGH_BITS_OFFSET)
2957 		ioaddr |= (unsigned long)tmp.port_high << HIGH_BITS_OFFSET;
2958 	return sprintf(buf, "0x%lX\n", ioaddr);
2959 }
2960 
irq_show(struct device * dev,struct device_attribute * attr,char * buf)2961 static ssize_t irq_show(struct device *dev,
2962 	struct device_attribute *attr, char *buf)
2963 {
2964 	struct serial_struct tmp;
2965 	struct tty_port *port = dev_get_drvdata(dev);
2966 
2967 	uart_get_info(port, &tmp);
2968 	return sprintf(buf, "%d\n", tmp.irq);
2969 }
2970 
flags_show(struct device * dev,struct device_attribute * attr,char * buf)2971 static ssize_t flags_show(struct device *dev,
2972 	struct device_attribute *attr, char *buf)
2973 {
2974 	struct serial_struct tmp;
2975 	struct tty_port *port = dev_get_drvdata(dev);
2976 
2977 	uart_get_info(port, &tmp);
2978 	return sprintf(buf, "0x%X\n", tmp.flags);
2979 }
2980 
xmit_fifo_size_show(struct device * dev,struct device_attribute * attr,char * buf)2981 static ssize_t xmit_fifo_size_show(struct device *dev,
2982 	struct device_attribute *attr, char *buf)
2983 {
2984 	struct serial_struct tmp;
2985 	struct tty_port *port = dev_get_drvdata(dev);
2986 
2987 	uart_get_info(port, &tmp);
2988 	return sprintf(buf, "%d\n", tmp.xmit_fifo_size);
2989 }
2990 
close_delay_show(struct device * dev,struct device_attribute * attr,char * buf)2991 static ssize_t close_delay_show(struct device *dev,
2992 	struct device_attribute *attr, char *buf)
2993 {
2994 	struct serial_struct tmp;
2995 	struct tty_port *port = dev_get_drvdata(dev);
2996 
2997 	uart_get_info(port, &tmp);
2998 	return sprintf(buf, "%d\n", tmp.close_delay);
2999 }
3000 
closing_wait_show(struct device * dev,struct device_attribute * attr,char * buf)3001 static ssize_t closing_wait_show(struct device *dev,
3002 	struct device_attribute *attr, char *buf)
3003 {
3004 	struct serial_struct tmp;
3005 	struct tty_port *port = dev_get_drvdata(dev);
3006 
3007 	uart_get_info(port, &tmp);
3008 	return sprintf(buf, "%d\n", tmp.closing_wait);
3009 }
3010 
custom_divisor_show(struct device * dev,struct device_attribute * attr,char * buf)3011 static ssize_t custom_divisor_show(struct device *dev,
3012 	struct device_attribute *attr, char *buf)
3013 {
3014 	struct serial_struct tmp;
3015 	struct tty_port *port = dev_get_drvdata(dev);
3016 
3017 	uart_get_info(port, &tmp);
3018 	return sprintf(buf, "%d\n", tmp.custom_divisor);
3019 }
3020 
io_type_show(struct device * dev,struct device_attribute * attr,char * buf)3021 static ssize_t io_type_show(struct device *dev,
3022 	struct device_attribute *attr, char *buf)
3023 {
3024 	struct serial_struct tmp;
3025 	struct tty_port *port = dev_get_drvdata(dev);
3026 
3027 	uart_get_info(port, &tmp);
3028 	return sprintf(buf, "%d\n", tmp.io_type);
3029 }
3030 
iomem_base_show(struct device * dev,struct device_attribute * attr,char * buf)3031 static ssize_t iomem_base_show(struct device *dev,
3032 	struct device_attribute *attr, char *buf)
3033 {
3034 	struct serial_struct tmp;
3035 	struct tty_port *port = dev_get_drvdata(dev);
3036 
3037 	uart_get_info(port, &tmp);
3038 	return sprintf(buf, "0x%lX\n", (unsigned long)tmp.iomem_base);
3039 }
3040 
iomem_reg_shift_show(struct device * dev,struct device_attribute * attr,char * buf)3041 static ssize_t iomem_reg_shift_show(struct device *dev,
3042 	struct device_attribute *attr, char *buf)
3043 {
3044 	struct serial_struct tmp;
3045 	struct tty_port *port = dev_get_drvdata(dev);
3046 
3047 	uart_get_info(port, &tmp);
3048 	return sprintf(buf, "%d\n", tmp.iomem_reg_shift);
3049 }
3050 
console_show(struct device * dev,struct device_attribute * attr,char * buf)3051 static ssize_t console_show(struct device *dev,
3052 	struct device_attribute *attr, char *buf)
3053 {
3054 	struct tty_port *port = dev_get_drvdata(dev);
3055 	struct uart_state *state = container_of(port, struct uart_state, port);
3056 	struct uart_port *uport;
3057 	bool console = false;
3058 
3059 	mutex_lock(&port->mutex);
3060 	uport = uart_port_check(state);
3061 	if (uport)
3062 		console = uart_console_registered(uport);
3063 	mutex_unlock(&port->mutex);
3064 
3065 	return sprintf(buf, "%c\n", console ? 'Y' : 'N');
3066 }
3067 
console_store(struct device * dev,struct device_attribute * attr,const char * buf,size_t count)3068 static ssize_t console_store(struct device *dev,
3069 	struct device_attribute *attr, const char *buf, size_t count)
3070 {
3071 	struct tty_port *port = dev_get_drvdata(dev);
3072 	struct uart_state *state = container_of(port, struct uart_state, port);
3073 	struct uart_port *uport;
3074 	bool oldconsole, newconsole;
3075 	int ret;
3076 
3077 	ret = kstrtobool(buf, &newconsole);
3078 	if (ret)
3079 		return ret;
3080 
3081 	mutex_lock(&port->mutex);
3082 	uport = uart_port_check(state);
3083 	if (uport) {
3084 		oldconsole = uart_console_registered(uport);
3085 		if (oldconsole && !newconsole) {
3086 			ret = unregister_console(uport->cons);
3087 		} else if (!oldconsole && newconsole) {
3088 			if (uart_console(uport)) {
3089 				uport->console_reinit = 1;
3090 				register_console(uport->cons);
3091 			} else {
3092 				ret = -ENOENT;
3093 			}
3094 		}
3095 	} else {
3096 		ret = -ENXIO;
3097 	}
3098 	mutex_unlock(&port->mutex);
3099 
3100 	return ret < 0 ? ret : count;
3101 }
3102 
3103 static DEVICE_ATTR_RO(uartclk);
3104 static DEVICE_ATTR_RO(type);
3105 static DEVICE_ATTR_RO(line);
3106 static DEVICE_ATTR_RO(port);
3107 static DEVICE_ATTR_RO(irq);
3108 static DEVICE_ATTR_RO(flags);
3109 static DEVICE_ATTR_RO(xmit_fifo_size);
3110 static DEVICE_ATTR_RO(close_delay);
3111 static DEVICE_ATTR_RO(closing_wait);
3112 static DEVICE_ATTR_RO(custom_divisor);
3113 static DEVICE_ATTR_RO(io_type);
3114 static DEVICE_ATTR_RO(iomem_base);
3115 static DEVICE_ATTR_RO(iomem_reg_shift);
3116 static DEVICE_ATTR_RW(console);
3117 
3118 static struct attribute *tty_dev_attrs[] = {
3119 	&dev_attr_uartclk.attr,
3120 	&dev_attr_type.attr,
3121 	&dev_attr_line.attr,
3122 	&dev_attr_port.attr,
3123 	&dev_attr_irq.attr,
3124 	&dev_attr_flags.attr,
3125 	&dev_attr_xmit_fifo_size.attr,
3126 	&dev_attr_close_delay.attr,
3127 	&dev_attr_closing_wait.attr,
3128 	&dev_attr_custom_divisor.attr,
3129 	&dev_attr_io_type.attr,
3130 	&dev_attr_iomem_base.attr,
3131 	&dev_attr_iomem_reg_shift.attr,
3132 	&dev_attr_console.attr,
3133 	NULL
3134 };
3135 
3136 static const struct attribute_group tty_dev_attr_group = {
3137 	.attrs = tty_dev_attrs,
3138 };
3139 
3140 /**
3141  * serial_core_add_one_port - attach a driver-defined port structure
3142  * @drv: pointer to the uart low level driver structure for this port
3143  * @uport: uart port structure to use for this port.
3144  *
3145  * Context: task context, might sleep
3146  *
3147  * This allows the driver @drv to register its own uart_port structure with the
3148  * core driver. The main purpose is to allow the low level uart drivers to
3149  * expand uart_port, rather than having yet more levels of structures.
3150  * Caller must hold port_mutex.
3151  */
serial_core_add_one_port(struct uart_driver * drv,struct uart_port * uport)3152 static int serial_core_add_one_port(struct uart_driver *drv, struct uart_port *uport)
3153 {
3154 	struct uart_state *state;
3155 	struct tty_port *port;
3156 	int ret = 0;
3157 	struct device *tty_dev;
3158 	int num_groups;
3159 
3160 	if (uport->line >= drv->nr)
3161 		return -EINVAL;
3162 
3163 	state = drv->state + uport->line;
3164 	port = &state->port;
3165 
3166 	mutex_lock(&port->mutex);
3167 	if (state->uart_port) {
3168 		ret = -EINVAL;
3169 		goto out;
3170 	}
3171 
3172 	/* Link the port to the driver state table and vice versa */
3173 	atomic_set(&state->refcount, 1);
3174 	init_waitqueue_head(&state->remove_wait);
3175 	state->uart_port = uport;
3176 	uport->state = state;
3177 
3178 	state->pm_state = UART_PM_STATE_UNDEFINED;
3179 	uport->cons = drv->cons;
3180 	uport->minor = drv->tty_driver->minor_start + uport->line;
3181 	uport->name = kasprintf(GFP_KERNEL, "%s%d", drv->dev_name,
3182 				drv->tty_driver->name_base + uport->line);
3183 	if (!uport->name) {
3184 		ret = -ENOMEM;
3185 		goto out;
3186 	}
3187 
3188 	/*
3189 	 * If this port is in use as a console then the spinlock is already
3190 	 * initialised.
3191 	 */
3192 	if (!uart_console_registered(uport))
3193 		uart_port_spin_lock_init(uport);
3194 
3195 	if (uport->cons && uport->dev)
3196 		of_console_check(uport->dev->of_node, uport->cons->name, uport->line);
3197 
3198 	tty_port_link_device(port, drv->tty_driver, uport->line);
3199 	uart_configure_port(drv, state, uport);
3200 
3201 	port->console = uart_console(uport);
3202 
3203 	num_groups = 2;
3204 	if (uport->attr_group)
3205 		num_groups++;
3206 
3207 	uport->tty_groups = kcalloc(num_groups, sizeof(*uport->tty_groups),
3208 				    GFP_KERNEL);
3209 	if (!uport->tty_groups) {
3210 		ret = -ENOMEM;
3211 		goto out;
3212 	}
3213 	uport->tty_groups[0] = &tty_dev_attr_group;
3214 	if (uport->attr_group)
3215 		uport->tty_groups[1] = uport->attr_group;
3216 
3217 	/*
3218 	 * Register the port whether it's detected or not.  This allows
3219 	 * setserial to be used to alter this port's parameters.
3220 	 */
3221 	tty_dev = tty_port_register_device_attr_serdev(port, drv->tty_driver,
3222 			uport->line, uport->dev, port, uport->tty_groups);
3223 	if (!IS_ERR(tty_dev)) {
3224 		device_set_wakeup_capable(tty_dev, 1);
3225 	} else {
3226 		dev_err(uport->dev, "Cannot register tty device on line %d\n",
3227 		       uport->line);
3228 	}
3229 
3230  out:
3231 	mutex_unlock(&port->mutex);
3232 
3233 	return ret;
3234 }
3235 
3236 /**
3237  * serial_core_remove_one_port - detach a driver defined port structure
3238  * @drv: pointer to the uart low level driver structure for this port
3239  * @uport: uart port structure for this port
3240  *
3241  * Context: task context, might sleep
3242  *
3243  * This unhooks (and hangs up) the specified port structure from the core
3244  * driver. No further calls will be made to the low-level code for this port.
3245  * Caller must hold port_mutex.
3246  */
serial_core_remove_one_port(struct uart_driver * drv,struct uart_port * uport)3247 static void serial_core_remove_one_port(struct uart_driver *drv,
3248 					struct uart_port *uport)
3249 {
3250 	struct uart_state *state = drv->state + uport->line;
3251 	struct tty_port *port = &state->port;
3252 	struct uart_port *uart_port;
3253 	struct tty_struct *tty;
3254 
3255 	mutex_lock(&port->mutex);
3256 	uart_port = uart_port_check(state);
3257 	if (uart_port != uport)
3258 		dev_alert(uport->dev, "Removing wrong port: %p != %p\n",
3259 			  uart_port, uport);
3260 
3261 	if (!uart_port) {
3262 		mutex_unlock(&port->mutex);
3263 		return;
3264 	}
3265 	mutex_unlock(&port->mutex);
3266 
3267 	/*
3268 	 * Remove the devices from the tty layer
3269 	 */
3270 	tty_port_unregister_device(port, drv->tty_driver, uport->line);
3271 
3272 	tty = tty_port_tty_get(port);
3273 	if (tty) {
3274 		tty_vhangup(port->tty);
3275 		tty_kref_put(tty);
3276 	}
3277 
3278 	/*
3279 	 * If the port is used as a console, unregister it
3280 	 */
3281 	if (uart_console(uport))
3282 		unregister_console(uport->cons);
3283 
3284 	/*
3285 	 * Free the port IO and memory resources, if any.
3286 	 */
3287 	if (uport->type != PORT_UNKNOWN && uport->ops->release_port)
3288 		uport->ops->release_port(uport);
3289 	kfree(uport->tty_groups);
3290 	kfree(uport->name);
3291 
3292 	/*
3293 	 * Indicate that there isn't a port here anymore.
3294 	 */
3295 	uport->type = PORT_UNKNOWN;
3296 	uport->port_dev = NULL;
3297 
3298 	mutex_lock(&port->mutex);
3299 	WARN_ON(atomic_dec_return(&state->refcount) < 0);
3300 	wait_event(state->remove_wait, !atomic_read(&state->refcount));
3301 	state->uart_port = NULL;
3302 	mutex_unlock(&port->mutex);
3303 }
3304 
3305 /**
3306  * uart_match_port - are the two ports equivalent?
3307  * @port1: first port
3308  * @port2: second port
3309  *
3310  * This utility function can be used to determine whether two uart_port
3311  * structures describe the same port.
3312  */
uart_match_port(const struct uart_port * port1,const struct uart_port * port2)3313 bool uart_match_port(const struct uart_port *port1,
3314 		const struct uart_port *port2)
3315 {
3316 	if (port1->iotype != port2->iotype)
3317 		return false;
3318 
3319 	switch (port1->iotype) {
3320 	case UPIO_PORT:
3321 		return port1->iobase == port2->iobase;
3322 	case UPIO_HUB6:
3323 		return port1->iobase == port2->iobase &&
3324 		       port1->hub6   == port2->hub6;
3325 	case UPIO_MEM:
3326 	case UPIO_MEM16:
3327 	case UPIO_MEM32:
3328 	case UPIO_MEM32BE:
3329 	case UPIO_AU:
3330 	case UPIO_TSI:
3331 		return port1->mapbase == port2->mapbase;
3332 	}
3333 
3334 	return false;
3335 }
3336 EXPORT_SYMBOL(uart_match_port);
3337 
3338 static struct serial_ctrl_device *
serial_core_get_ctrl_dev(struct serial_port_device * port_dev)3339 serial_core_get_ctrl_dev(struct serial_port_device *port_dev)
3340 {
3341 	struct device *dev = &port_dev->dev;
3342 
3343 	return to_serial_base_ctrl_device(dev->parent);
3344 }
3345 
3346 /*
3347  * Find a registered serial core controller device if one exists. Returns
3348  * the first device matching the ctrl_id. Caller must hold port_mutex.
3349  */
serial_core_ctrl_find(struct uart_driver * drv,struct device * phys_dev,int ctrl_id)3350 static struct serial_ctrl_device *serial_core_ctrl_find(struct uart_driver *drv,
3351 							struct device *phys_dev,
3352 							int ctrl_id)
3353 {
3354 	struct uart_state *state;
3355 	int i;
3356 
3357 	lockdep_assert_held(&port_mutex);
3358 
3359 	for (i = 0; i < drv->nr; i++) {
3360 		state = drv->state + i;
3361 		if (!state->uart_port || !state->uart_port->port_dev)
3362 			continue;
3363 
3364 		if (state->uart_port->dev == phys_dev &&
3365 		    state->uart_port->ctrl_id == ctrl_id)
3366 			return serial_core_get_ctrl_dev(state->uart_port->port_dev);
3367 	}
3368 
3369 	return NULL;
3370 }
3371 
serial_core_ctrl_device_add(struct uart_port * port)3372 static struct serial_ctrl_device *serial_core_ctrl_device_add(struct uart_port *port)
3373 {
3374 	return serial_base_ctrl_add(port, port->dev);
3375 }
3376 
serial_core_port_device_add(struct serial_ctrl_device * ctrl_dev,struct uart_port * port)3377 static int serial_core_port_device_add(struct serial_ctrl_device *ctrl_dev,
3378 				       struct uart_port *port)
3379 {
3380 	struct serial_port_device *port_dev;
3381 
3382 	port_dev = serial_base_port_add(port, ctrl_dev);
3383 	if (IS_ERR(port_dev))
3384 		return PTR_ERR(port_dev);
3385 
3386 	port->port_dev = port_dev;
3387 
3388 	return 0;
3389 }
3390 
3391 /*
3392  * Initialize a serial core port device, and a controller device if needed.
3393  */
serial_core_register_port(struct uart_driver * drv,struct uart_port * port)3394 int serial_core_register_port(struct uart_driver *drv, struct uart_port *port)
3395 {
3396 	struct serial_ctrl_device *ctrl_dev, *new_ctrl_dev = NULL;
3397 	int ret;
3398 
3399 	mutex_lock(&port_mutex);
3400 
3401 	/*
3402 	 * Prevent serial_port_runtime_resume() from trying to use the port
3403 	 * until serial_core_add_one_port() has completed
3404 	 */
3405 	port->flags |= UPF_DEAD;
3406 
3407 	/* Inititalize a serial core controller device if needed */
3408 	ctrl_dev = serial_core_ctrl_find(drv, port->dev, port->ctrl_id);
3409 	if (!ctrl_dev) {
3410 		new_ctrl_dev = serial_core_ctrl_device_add(port);
3411 		if (IS_ERR(new_ctrl_dev)) {
3412 			ret = PTR_ERR(new_ctrl_dev);
3413 			goto err_unlock;
3414 		}
3415 		ctrl_dev = new_ctrl_dev;
3416 	}
3417 
3418 	/*
3419 	 * Initialize a serial core port device. Tag the port dead to prevent
3420 	 * serial_port_runtime_resume() trying to do anything until port has
3421 	 * been registered. It gets cleared by serial_core_add_one_port().
3422 	 */
3423 	ret = serial_core_port_device_add(ctrl_dev, port);
3424 	if (ret)
3425 		goto err_unregister_ctrl_dev;
3426 
3427 	ret = serial_core_add_one_port(drv, port);
3428 	if (ret)
3429 		goto err_unregister_port_dev;
3430 
3431 	port->flags &= ~UPF_DEAD;
3432 
3433 	mutex_unlock(&port_mutex);
3434 
3435 	return 0;
3436 
3437 err_unregister_port_dev:
3438 	serial_base_port_device_remove(port->port_dev);
3439 
3440 err_unregister_ctrl_dev:
3441 	serial_base_ctrl_device_remove(new_ctrl_dev);
3442 
3443 err_unlock:
3444 	mutex_unlock(&port_mutex);
3445 
3446 	return ret;
3447 }
3448 
3449 /*
3450  * Removes a serial core port device, and the related serial core controller
3451  * device if the last instance.
3452  */
serial_core_unregister_port(struct uart_driver * drv,struct uart_port * port)3453 void serial_core_unregister_port(struct uart_driver *drv, struct uart_port *port)
3454 {
3455 	struct device *phys_dev = port->dev;
3456 	struct serial_port_device *port_dev = port->port_dev;
3457 	struct serial_ctrl_device *ctrl_dev = serial_core_get_ctrl_dev(port_dev);
3458 	int ctrl_id = port->ctrl_id;
3459 
3460 	mutex_lock(&port_mutex);
3461 
3462 	port->flags |= UPF_DEAD;
3463 
3464 	serial_core_remove_one_port(drv, port);
3465 
3466 	/* Note that struct uart_port *port is no longer valid at this point */
3467 	serial_base_port_device_remove(port_dev);
3468 
3469 	/* Drop the serial core controller device if no ports are using it */
3470 	if (!serial_core_ctrl_find(drv, phys_dev, ctrl_id))
3471 		serial_base_ctrl_device_remove(ctrl_dev);
3472 
3473 	mutex_unlock(&port_mutex);
3474 }
3475 
3476 /**
3477  * uart_handle_dcd_change - handle a change of carrier detect state
3478  * @uport: uart_port structure for the open port
3479  * @active: new carrier detect status
3480  *
3481  * Caller must hold uport->lock.
3482  */
uart_handle_dcd_change(struct uart_port * uport,bool active)3483 void uart_handle_dcd_change(struct uart_port *uport, bool active)
3484 {
3485 	struct tty_port *port = &uport->state->port;
3486 	struct tty_struct *tty = port->tty;
3487 	struct tty_ldisc *ld;
3488 
3489 	lockdep_assert_held_once(&uport->lock);
3490 
3491 	if (tty) {
3492 		ld = tty_ldisc_ref(tty);
3493 		if (ld) {
3494 			if (ld->ops->dcd_change)
3495 				ld->ops->dcd_change(tty, active);
3496 			tty_ldisc_deref(ld);
3497 		}
3498 	}
3499 
3500 	uport->icount.dcd++;
3501 
3502 	if (uart_dcd_enabled(uport)) {
3503 		if (active)
3504 			wake_up_interruptible(&port->open_wait);
3505 		else if (tty)
3506 			tty_hangup(tty);
3507 	}
3508 }
3509 EXPORT_SYMBOL_GPL(uart_handle_dcd_change);
3510 
3511 /**
3512  * uart_handle_cts_change - handle a change of clear-to-send state
3513  * @uport: uart_port structure for the open port
3514  * @active: new clear-to-send status
3515  *
3516  * Caller must hold uport->lock.
3517  */
uart_handle_cts_change(struct uart_port * uport,bool active)3518 void uart_handle_cts_change(struct uart_port *uport, bool active)
3519 {
3520 	lockdep_assert_held_once(&uport->lock);
3521 
3522 	uport->icount.cts++;
3523 
3524 	if (uart_softcts_mode(uport)) {
3525 		if (uport->hw_stopped) {
3526 			if (active) {
3527 				uport->hw_stopped = false;
3528 				uport->ops->start_tx(uport);
3529 				uart_write_wakeup(uport);
3530 			}
3531 		} else {
3532 			if (!active) {
3533 				uport->hw_stopped = true;
3534 				uport->ops->stop_tx(uport);
3535 			}
3536 		}
3537 
3538 	}
3539 }
3540 EXPORT_SYMBOL_GPL(uart_handle_cts_change);
3541 
3542 /**
3543  * uart_insert_char - push a char to the uart layer
3544  *
3545  * User is responsible to call tty_flip_buffer_push when they are done with
3546  * insertion.
3547  *
3548  * @port: corresponding port
3549  * @status: state of the serial port RX buffer (LSR for 8250)
3550  * @overrun: mask of overrun bits in @status
3551  * @ch: character to push
3552  * @flag: flag for the character (see TTY_NORMAL and friends)
3553  */
uart_insert_char(struct uart_port * port,unsigned int status,unsigned int overrun,u8 ch,u8 flag)3554 void uart_insert_char(struct uart_port *port, unsigned int status,
3555 		      unsigned int overrun, u8 ch, u8 flag)
3556 {
3557 	struct tty_port *tport = &port->state->port;
3558 
3559 	if ((status & port->ignore_status_mask & ~overrun) == 0)
3560 		if (tty_insert_flip_char(tport, ch, flag) == 0)
3561 			++port->icount.buf_overrun;
3562 
3563 	/*
3564 	 * Overrun is special.  Since it's reported immediately,
3565 	 * it doesn't affect the current character.
3566 	 */
3567 	if (status & ~port->ignore_status_mask & overrun)
3568 		if (tty_insert_flip_char(tport, 0, TTY_OVERRUN) == 0)
3569 			++port->icount.buf_overrun;
3570 }
3571 EXPORT_SYMBOL_GPL(uart_insert_char);
3572 
3573 #ifdef CONFIG_MAGIC_SYSRQ_SERIAL
3574 static const u8 sysrq_toggle_seq[] = CONFIG_MAGIC_SYSRQ_SERIAL_SEQUENCE;
3575 
uart_sysrq_on(struct work_struct * w)3576 static void uart_sysrq_on(struct work_struct *w)
3577 {
3578 	int sysrq_toggle_seq_len = strlen(sysrq_toggle_seq);
3579 
3580 	sysrq_toggle_support(1);
3581 	pr_info("SysRq is enabled by magic sequence '%*pE' on serial\n",
3582 		sysrq_toggle_seq_len, sysrq_toggle_seq);
3583 }
3584 static DECLARE_WORK(sysrq_enable_work, uart_sysrq_on);
3585 
3586 /**
3587  * uart_try_toggle_sysrq - Enables SysRq from serial line
3588  * @port: uart_port structure where char(s) after BREAK met
3589  * @ch: new character in the sequence after received BREAK
3590  *
3591  * Enables magic SysRq when the required sequence is met on port
3592  * (see CONFIG_MAGIC_SYSRQ_SERIAL_SEQUENCE).
3593  *
3594  * Returns: %false if @ch is out of enabling sequence and should be
3595  * handled some other way, %true if @ch was consumed.
3596  */
uart_try_toggle_sysrq(struct uart_port * port,u8 ch)3597 bool uart_try_toggle_sysrq(struct uart_port *port, u8 ch)
3598 {
3599 	int sysrq_toggle_seq_len = strlen(sysrq_toggle_seq);
3600 
3601 	if (!sysrq_toggle_seq_len)
3602 		return false;
3603 
3604 	BUILD_BUG_ON(ARRAY_SIZE(sysrq_toggle_seq) >= U8_MAX);
3605 	if (sysrq_toggle_seq[port->sysrq_seq] != ch) {
3606 		port->sysrq_seq = 0;
3607 		return false;
3608 	}
3609 
3610 	if (++port->sysrq_seq < sysrq_toggle_seq_len) {
3611 		port->sysrq = jiffies + SYSRQ_TIMEOUT;
3612 		return true;
3613 	}
3614 
3615 	schedule_work(&sysrq_enable_work);
3616 
3617 	port->sysrq = 0;
3618 	return true;
3619 }
3620 EXPORT_SYMBOL_GPL(uart_try_toggle_sysrq);
3621 #endif
3622 
3623 /**
3624  * uart_get_rs485_mode() - retrieve rs485 properties for given uart
3625  * @port: uart device's target port
3626  *
3627  * This function implements the device tree binding described in
3628  * Documentation/devicetree/bindings/serial/rs485.txt.
3629  */
uart_get_rs485_mode(struct uart_port * port)3630 int uart_get_rs485_mode(struct uart_port *port)
3631 {
3632 	struct serial_rs485 *rs485conf = &port->rs485;
3633 	struct device *dev = port->dev;
3634 	enum gpiod_flags dflags;
3635 	struct gpio_desc *desc;
3636 	u32 rs485_delay[2];
3637 	int ret;
3638 
3639 	if (!(port->rs485_supported.flags & SER_RS485_ENABLED))
3640 		return 0;
3641 
3642 	ret = device_property_read_u32_array(dev, "rs485-rts-delay",
3643 					     rs485_delay, 2);
3644 	if (!ret) {
3645 		rs485conf->delay_rts_before_send = rs485_delay[0];
3646 		rs485conf->delay_rts_after_send = rs485_delay[1];
3647 	} else {
3648 		rs485conf->delay_rts_before_send = 0;
3649 		rs485conf->delay_rts_after_send = 0;
3650 	}
3651 
3652 	uart_sanitize_serial_rs485_delays(port, rs485conf);
3653 
3654 	/*
3655 	 * Clear full-duplex and enabled flags, set RTS polarity to active high
3656 	 * to get to a defined state with the following properties:
3657 	 */
3658 	rs485conf->flags &= ~(SER_RS485_RX_DURING_TX | SER_RS485_ENABLED |
3659 			      SER_RS485_TERMINATE_BUS |
3660 			      SER_RS485_RTS_AFTER_SEND);
3661 	rs485conf->flags |= SER_RS485_RTS_ON_SEND;
3662 
3663 	if (device_property_read_bool(dev, "rs485-rx-during-tx"))
3664 		rs485conf->flags |= SER_RS485_RX_DURING_TX;
3665 
3666 	if (device_property_read_bool(dev, "linux,rs485-enabled-at-boot-time"))
3667 		rs485conf->flags |= SER_RS485_ENABLED;
3668 
3669 	if (device_property_read_bool(dev, "rs485-rts-active-low")) {
3670 		rs485conf->flags &= ~SER_RS485_RTS_ON_SEND;
3671 		rs485conf->flags |= SER_RS485_RTS_AFTER_SEND;
3672 	}
3673 
3674 	/*
3675 	 * Disabling termination by default is the safe choice:  Else if many
3676 	 * bus participants enable it, no communication is possible at all.
3677 	 * Works fine for short cables and users may enable for longer cables.
3678 	 */
3679 	desc = devm_gpiod_get_optional(dev, "rs485-term", GPIOD_OUT_LOW);
3680 	if (IS_ERR(desc))
3681 		return dev_err_probe(dev, PTR_ERR(desc), "Cannot get rs485-term-gpios\n");
3682 	port->rs485_term_gpio = desc;
3683 	if (port->rs485_term_gpio)
3684 		port->rs485_supported.flags |= SER_RS485_TERMINATE_BUS;
3685 
3686 	dflags = (rs485conf->flags & SER_RS485_RX_DURING_TX) ?
3687 		 GPIOD_OUT_HIGH : GPIOD_OUT_LOW;
3688 	desc = devm_gpiod_get_optional(dev, "rs485-rx-during-tx", dflags);
3689 	if (IS_ERR(desc))
3690 		return dev_err_probe(dev, PTR_ERR(desc), "Cannot get rs485-rx-during-tx-gpios\n");
3691 	port->rs485_rx_during_tx_gpio = desc;
3692 	if (port->rs485_rx_during_tx_gpio)
3693 		port->rs485_supported.flags |= SER_RS485_RX_DURING_TX;
3694 
3695 	return 0;
3696 }
3697 EXPORT_SYMBOL_GPL(uart_get_rs485_mode);
3698 
3699 /* Compile-time assertions for serial_rs485 layout */
3700 static_assert(offsetof(struct serial_rs485, padding) ==
3701               (offsetof(struct serial_rs485, delay_rts_after_send) + sizeof(__u32)));
3702 static_assert(offsetof(struct serial_rs485, padding1) ==
3703 	      offsetof(struct serial_rs485, padding[1]));
3704 static_assert((offsetof(struct serial_rs485, padding[4]) + sizeof(__u32)) ==
3705 	      sizeof(struct serial_rs485));
3706 
3707 MODULE_DESCRIPTION("Serial driver core");
3708 MODULE_LICENSE("GPL");
3709