linux - drivers/tty/serial/serial

3669 lines · 93.3 KiB

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	#include "8250/8250.h" /* For hub6_match_port() */
37
38	/*
39	* This is used to lock changes in serial line configuration.
40	*/
41	static DEFINE_MUTEX(port_mutex);
42
43	/*
44	* lockdep: port->lock is initialized in two places, but we
45	* want only one lock-class:
46	*/
47	static struct lock_class_key port_lock_key;
48
49	#define HIGH_BITS_OFFSET ((sizeof(long)-sizeof(int))*8)
50
51	/*
52	* Max time with active RTS before/after data is sent.
53	*/
54	#define RS485_MAX_RTS_DELAY 100 /* msecs */
55
56	static void uart_change_pm(struct uart_state *state,
57	enum uart_pm_state pm_state);
58
59	static void uart_port_shutdown(struct tty_port *port);
60
61	static int uart_dcd_enabled(struct uart_port *uport)
62	{
63	return !!(uport->status & UPSTAT_DCD_ENABLE);
64	}
65
66	static inline struct uart_port uart_port_ref(struct uart_state state)
67	{
68	if (atomic_add_unless(&state->refcount, 1, 0))
69	return state->uart_port;
70	return NULL;
71	}
72
73	static inline void uart_port_deref(struct uart_port *uport)
74	{
75	if (atomic_dec_and_test(&uport->state->refcount))
76	wake_up(&uport->state->remove_wait);
77	}
78
79	static inline struct uart_port uart_port_ref_lock(struct uart_state state, unsigned long *flags)
80	{
81	struct uart_port *uport = uart_port_ref(state);
82
83	if (uport)
84	uart_port_lock_irqsave(uport, flags);
85
86	return uport;
87	}
88
89	static inline void uart_port_unlock_deref(struct uart_port *uport, unsigned long flags)
90	{
91	if (uport) {
92	uart_port_unlock_irqrestore(uport, flags);
93	uart_port_deref(uport);
94	}
95	}
96
97	static inline struct uart_port uart_port_check(struct uart_state state)
98	{
99	lockdep_assert_held(&state->port.mutex);
100	return state->uart_port;
101	}
102
103	/**
104	* uart_write_wakeup - schedule write processing
105	* @port: port to be processed
106	*
107	* This routine is used by the interrupt handler to schedule processing in the
108	* software interrupt portion of the driver. A driver is expected to call this
109	* function when the number of characters in the transmit buffer have dropped
110	* below a threshold.
111	*
112	* Locking: @port->lock should be held
113	*/
114	void uart_write_wakeup(struct uart_port *port)
115	{
116	struct uart_state *state = port->state;
117	/*
118	* This means you called this function _after_ the port was
119	* closed. No cookie for you.
120	*/
121	BUG_ON(!state);
122	tty_port_tty_wakeup(&state->port);
123	}
124	EXPORT_SYMBOL(uart_write_wakeup);
125
126	static void uart_stop(struct tty_struct *tty)
127	{
128	struct uart_state *state = tty->driver_data;
129	struct uart_port *port;
130	unsigned long flags;
131
132	port = uart_port_ref_lock(state, &flags);
133	if (port)
134	port->ops->stop_tx(port);
135	uart_port_unlock_deref(port, flags);
136	}
137
138	static void __uart_start(struct uart_state *state)
139	{
140	struct uart_port *port = state->uart_port;
141	struct serial_port_device *port_dev;
142	int err;
143
144	if (!port \|\| port->flags & UPF_DEAD \|\| uart_tx_stopped(port))
145	return;
146
147	port_dev = port->port_dev;
148
149	/* Increment the runtime PM usage count for the active check below */
150	err = pm_runtime_get(&port_dev->dev);
151	if (err < 0 && err != -EINPROGRESS) {
152	pm_runtime_put_noidle(&port_dev->dev);
153	return;
154	}
155
156	/*
157	* Start TX if enabled, and kick runtime PM. If the device is not
158	* enabled, serial_port_runtime_resume() calls start_tx() again
159	* after enabling the device.
160	*/
161	if (!pm_runtime_enabled(port->dev) \|\| pm_runtime_active(&port_dev->dev))
162	port->ops->start_tx(port);
163	pm_runtime_mark_last_busy(&port_dev->dev);
164	pm_runtime_put_autosuspend(&port_dev->dev);
165	}
166
167	static void uart_start(struct tty_struct *tty)
168	{
169	struct uart_state *state = tty->driver_data;
170	struct uart_port *port;
171	unsigned long flags;
172
173	port = uart_port_ref_lock(state, &flags);
174	__uart_start(state);
175	uart_port_unlock_deref(port, flags);
176	}
177
178	static void
179	uart_update_mctrl(struct uart_port *port, unsigned int set, unsigned int clear)
180	{
181	unsigned int old;
182
183	guard(uart_port_lock_irqsave)(port);
184	old = port->mctrl;
185	port->mctrl = (old & ~clear) \| set;
186	if (old != port->mctrl && !(port->rs485.flags & SER_RS485_ENABLED))
187	port->ops->set_mctrl(port, port->mctrl);
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
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 */
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	guard(uart_port_lock_irq)(uport);
223	if (termios->c_cflag & CRTSCTS)
224	uport->status \|= UPSTAT_CTS_ENABLE;
225	else
226	uport->status &= ~UPSTAT_CTS_ENABLE;
227
228	if (termios->c_cflag & CLOCAL)
229	uport->status &= ~UPSTAT_DCD_ENABLE;
230	else
231	uport->status \|= UPSTAT_DCD_ENABLE;
232
233	/* reset sw-assisted CTS flow control based on (possibly) new mode */
234	old_hw_stopped = uport->hw_stopped;
235	uport->hw_stopped = uart_softcts_mode(uport) &&
236	!(uport->ops->get_mctrl(uport) & TIOCM_CTS);
237	if (uport->hw_stopped != old_hw_stopped) {
238	if (!old_hw_stopped)
239	uport->ops->stop_tx(uport);
240	else
241	__uart_start(state);
242	}
243	}
244
245	static int uart_alloc_xmit_buf(struct tty_port *port)
246	{
247	struct uart_state *state = container_of(port, struct uart_state, port);
248	struct uart_port *uport;
249	unsigned long flags;
250	unsigned long page;
251
252	/*
253	* Initialise and allocate the transmit and temporary
254	* buffer.
255	*/
256	page = get_zeroed_page(GFP_KERNEL);
257	if (!page)
258	return -ENOMEM;
259
260	uport = uart_port_ref_lock(state, &flags);
261	if (!state->port.xmit_buf) {
262	state->port.xmit_buf = (unsigned char *)page;
263	kfifo_init(&state->port.xmit_fifo, state->port.xmit_buf,
264	PAGE_SIZE);
265	uart_port_unlock_deref(uport, flags);
266	} else {
267	uart_port_unlock_deref(uport, flags);
268	/*
269	* Do not free() the page under the port lock, see
270	* uart_free_xmit_buf().
271	*/
272	free_page(page);
273	}
274
275	return 0;
276	}
277
278	static void uart_free_xmit_buf(struct tty_port *port)
279	{
280	struct uart_state *state = container_of(port, struct uart_state, port);
281	struct uart_port *uport;
282	unsigned long flags;
283	char *xmit_buf;
284
285	/*
286	* Do not free() the transmit buffer page under the port lock since
287	* this can create various circular locking scenarios. For instance,
288	* console driver may need to allocate/free a debug object, which
289	* can end up in printk() recursion.
290	*/
291	uport = uart_port_ref_lock(state, &flags);
292	xmit_buf = port->xmit_buf;
293	port->xmit_buf = NULL;
294	INIT_KFIFO(port->xmit_fifo);
295	uart_port_unlock_deref(uport, flags);
296
297	free_page((unsigned long)xmit_buf);
298	}
299
300	/*
301	* Startup the port. This will be called once per open. All calls
302	* will be serialised by the per-port mutex.
303	*/
304	static int uart_port_startup(struct tty_struct tty, struct uart_state state,
305	bool init_hw)
306	{
307	struct uart_port *uport = uart_port_check(state);
308	int retval;
309
310	if (uport->type == PORT_UNKNOWN)
311	return 1;
312
313	/*
314	* Make sure the device is in D0 state.
315	*/
316	uart_change_pm(state, UART_PM_STATE_ON);
317
318	retval = uart_alloc_xmit_buf(&state->port);
319	if (retval)
320	return retval;
321
322	retval = uport->ops->startup(uport);
323	if (retval == 0) {
324	if (uart_console(uport) && uport->cons->cflag) {
325	tty->termios.c_cflag = uport->cons->cflag;
326	tty->termios.c_ispeed = uport->cons->ispeed;
327	tty->termios.c_ospeed = uport->cons->ospeed;
328	uport->cons->cflag = 0;
329	uport->cons->ispeed = 0;
330	uport->cons->ospeed = 0;
331	}
332	/*
333	* Initialise the hardware port settings.
334	*/
335	uart_change_line_settings(tty, state, NULL);
336
337	/*
338	* Setup the RTS and DTR signals once the
339	* port is open and ready to respond.
340	*/
341	if (init_hw && C_BAUD(tty))
342	uart_port_dtr_rts(uport, true);
343	}
344
345	/*
346	* This is to allow setserial on this port. People may want to set
347	* port/irq/type and then reconfigure the port properly if it failed
348	* now.
349	*/
350	if (retval && capable(CAP_SYS_ADMIN))
351	return 1;
352
353	return retval;
354	}
355
356	static int uart_startup(struct tty_struct tty, struct uart_state state,
357	bool init_hw)
358	{
359	struct tty_port *port = &state->port;
360	struct uart_port *uport;
361	int retval;
362
363	if (tty_port_initialized(port))
364	goto out_base_port_startup;
365
366	retval = uart_port_startup(tty, state, init_hw);
367	if (retval) {
368	set_bit(TTY_IO_ERROR, &tty->flags);
369	return retval;
370	}
371
372	out_base_port_startup:
373	uport = uart_port_check(state);
374	if (!uport)
375	return -EIO;
376
377	serial_base_port_startup(uport);
378
379	return 0;
380	}
381
382	/*
383	* This routine will shutdown a serial port; interrupts are disabled, and
384	* DTR is dropped if the hangup on close termio flag is on. Calls to
385	* uart_shutdown are serialised by the per-port semaphore.
386	*
387	* uport == NULL if uart_port has already been removed
388	*/
389	static void uart_shutdown(struct tty_struct tty, struct uart_state state)
390	{
391	struct uart_port *uport = uart_port_check(state);
392	struct tty_port *port = &state->port;
393
394	/*
395	* Set the TTY IO error marker
396	*/
397	if (tty)
398	set_bit(TTY_IO_ERROR, &tty->flags);
399
400	if (uport)
401	serial_base_port_shutdown(uport);
402
403	if (tty_port_initialized(port)) {
404	tty_port_set_initialized(port, false);
405
406	/*
407	* Turn off DTR and RTS early.
408	*/
409	if (uport) {
410	if (uart_console(uport) && tty) {
411	uport->cons->cflag = tty->termios.c_cflag;
412	uport->cons->ispeed = tty->termios.c_ispeed;
413	uport->cons->ospeed = tty->termios.c_ospeed;
414	}
415
416	if (!tty \|\| C_HUPCL(tty))
417	uart_port_dtr_rts(uport, false);
418	}
419
420	uart_port_shutdown(port);
421	}
422
423	/*
424	* It's possible for shutdown to be called after suspend if we get
425	* a DCD drop (hangup) at just the right time. Clear suspended bit so
426	* we don't try to resume a port that has been shutdown.
427	*/
428	tty_port_set_suspended(port, false);
429
430	uart_free_xmit_buf(port);
431	}
432
433	/**
434	* uart_update_timeout - update per-port frame timing information
435	* @port: uart_port structure describing the port
436	* @cflag: termios cflag value
437	* @baud: speed of the port
438	*
439	* Set the @port frame timing information from which the FIFO timeout value is
440	* derived. The @cflag value should reflect the actual hardware settings as
441	* number of bits, parity, stop bits and baud rate is taken into account here.
442	*
443	* Locking: caller is expected to take @port->lock
444	*/
445	void
446	uart_update_timeout(struct uart_port *port, unsigned int cflag,
447	unsigned int baud)
448	{
449	u64 temp = tty_get_frame_size(cflag);
450
451	temp *= NSEC_PER_SEC;
452	port->frame_time = (unsigned int)DIV64_U64_ROUND_UP(temp, baud);
453	}
454	EXPORT_SYMBOL(uart_update_timeout);
455
456	/**
457	* uart_get_baud_rate - return baud rate for a particular port
458	* @port: uart_port structure describing the port in question.
459	* @termios: desired termios settings
460	* @old: old termios (or %NULL)
461	* @min: minimum acceptable baud rate
462	* @max: maximum acceptable baud rate
463	*
464	* Decode the termios structure into a numeric baud rate, taking account of the
465	* magic 38400 baud rate (with spd_* flags), and mapping the %B0 rate to 9600
466	* baud or min argument, whichever is greater.
467	*
468	* If the new baud rate is invalid, try the @old termios setting. If it's still
469	* invalid, clip to the nearest chip supported rate.
470	*
471	* The @termios structure is updated to reflect the baud rate we're actually
472	* going to be using. Don't do this for the case where B0 is requested ("hang
473	* up").
474	*
475	* Locking: caller dependent
476	*/
477	unsigned int
478	uart_get_baud_rate(struct uart_port port, struct ktermios termios,
479	const struct ktermios *old, unsigned int min, unsigned int max)
480	{
481	unsigned int try;
482	unsigned int baud;
483	unsigned int altbaud;
484	upf_t flags = port->flags & UPF_SPD_MASK;
485
486	switch (flags) {
487	case UPF_SPD_HI:
488	altbaud = 57600;
489	break;
490	case UPF_SPD_VHI:
491	altbaud = 115200;
492	break;
493	case UPF_SPD_SHI:
494	altbaud = 230400;
495	break;
496	case UPF_SPD_WARP:
497	altbaud = 460800;
498	break;
499	default:
500	altbaud = 38400;
501	break;
502	}
503
504	for (try = 0; try < 2; try++) {
505	baud = tty_termios_baud_rate(termios);
506
507	/*
508	* The spd_hi, spd_vhi, spd_shi, spd_warp kludge...
509	* Die! Die! Die!
510	*/
511	if (try == 0 && baud == 38400)
512	baud = altbaud;
513
514	/*
515	* Special case: B0 rate.
516	*/
517	if (baud == 0)
518	return max(min, 9600);
519
520	if (baud >= min && baud <= max)
521	return baud;
522
523	/*
524	* If the range cannot be met then try again with
525	* the old baud rate if possible.
526	*/
527	termios->c_cflag &= ~CBAUD;
528	if (old) {
529	baud = tty_termios_baud_rate(old);
530	tty_termios_encode_baud_rate(termios, baud, baud);
531	old = NULL;
532	continue;
533	}
534
535	/*
536	* As a last resort, if the range cannot be met then clip to
537	* the nearest chip supported rate.
538	*/
539	if (baud <= min)
540	baud = min + 1;
541	else
542	baud = max - 1;
543
544	tty_termios_encode_baud_rate(termios, baud, baud);
545	}
546
547	/* Should never happen */
548	WARN_ON(1);
549	return 0;
550	}
551	EXPORT_SYMBOL(uart_get_baud_rate);
552
553	/**
554	* uart_get_divisor - return uart clock divisor
555	* @port: uart_port structure describing the port
556	* @baud: desired baud rate
557	*
558	* Calculate the divisor (baud_base / baud) for the specified @baud,
559	* appropriately rounded.
560	*
561	* If 38400 baud and custom divisor is selected, return the custom divisor
562	* instead.
563	*
564	* Locking: caller dependent
565	*/
566	unsigned int
567	uart_get_divisor(struct uart_port *port, unsigned int baud)
568	{
569	unsigned int quot;
570
571	/*
572	* Old custom speed handling.
573	*/
574	if (baud == 38400 && (port->flags & UPF_SPD_MASK) == UPF_SPD_CUST)
575	quot = port->custom_divisor;
576	else
577	quot = DIV_ROUND_CLOSEST(port->uartclk, 16 * baud);
578
579	return quot;
580	}
581	EXPORT_SYMBOL(uart_get_divisor);
582
583	static int uart_put_char(struct tty_struct *tty, u8 c)
584	{
585	struct uart_state *state = tty->driver_data;
586	struct uart_port *port;
587	unsigned long flags;
588	int ret = 0;
589
590	port = uart_port_ref_lock(state, &flags);
591	if (!state->port.xmit_buf) {
592	uart_port_unlock_deref(port, flags);
593	return 0;
594	}
595
596	if (port)
597	ret = kfifo_put(&state->port.xmit_fifo, c);
598	uart_port_unlock_deref(port, flags);
599	return ret;
600	}
601
602	static void uart_flush_chars(struct tty_struct *tty)
603	{
604	uart_start(tty);
605	}
606
607	static ssize_t uart_write(struct tty_struct tty, const u8 buf, size_t count)
608	{
609	struct uart_state *state = tty->driver_data;
610	struct uart_port *port;
611	unsigned long flags;
612	int ret = 0;
613
614	/*
615	* This means you called this function _after_ the port was
616	* closed. No cookie for you.
617	*/
618	if (WARN_ON(!state))
619	return -EL3HLT;
620
621	port = uart_port_ref_lock(state, &flags);
622	if (!state->port.xmit_buf) {
623	uart_port_unlock_deref(port, flags);
624	return 0;
625	}
626
627	if (port)
628	ret = kfifo_in(&state->port.xmit_fifo, buf, count);
629
630	__uart_start(state);
631	uart_port_unlock_deref(port, flags);
632	return ret;
633	}
634
635	static unsigned int uart_write_room(struct tty_struct *tty)
636	{
637	struct uart_state *state = tty->driver_data;
638	struct uart_port *port;
639	unsigned long flags;
640	unsigned int ret;
641
642	port = uart_port_ref_lock(state, &flags);
643	if (!state->port.xmit_buf)
644	ret = 0;
645	else
646	ret = kfifo_avail(&state->port.xmit_fifo);
647	uart_port_unlock_deref(port, flags);
648	return ret;
649	}
650
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_ref_lock(state, &flags);
659	ret = kfifo_len(&state->port.xmit_fifo);
660	uart_port_unlock_deref(port, flags);
661	return ret;
662	}
663
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_ref_lock(state, &flags);
680	if (!port)
681	return;
682	kfifo_reset(&state->port.xmit_fifo);
683	if (port->ops->flush_buffer)
684	port->ops->flush_buffer(port);
685	uart_port_unlock_deref(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	*/
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	*/
707	static void uart_send_xchar(struct tty_struct *tty, u8 ch)
708	{
709	struct uart_state *state = tty->driver_data;
710	struct uart_port *port;
711
712	port = uart_port_ref(state);
713	if (!port)
714	return;
715
716	if (port->ops->send_xchar)
717	port->ops->send_xchar(port, ch);
718	else {
719	guard(uart_port_lock_irqsave)(port);
720	port->x_char = ch;
721	if (ch)
722	port->ops->start_tx(port);
723	}
724	uart_port_deref(port);
725	}
726
727	static void uart_throttle(struct tty_struct *tty)
728	{
729	struct uart_state *state = tty->driver_data;
730	upstat_t mask = UPSTAT_SYNC_FIFO;
731	struct uart_port *port;
732
733	port = uart_port_ref(state);
734	if (!port)
735	return;
736
737	if (I_IXOFF(tty))
738	mask \|= UPSTAT_AUTOXOFF;
739	if (C_CRTSCTS(tty))
740	mask \|= UPSTAT_AUTORTS;
741
742	if (port->status & mask) {
743	port->ops->throttle(port);
744	mask &= ~port->status;
745	}
746
747	if (mask & UPSTAT_AUTORTS)
748	uart_clear_mctrl(port, TIOCM_RTS);
749
750	if (mask & UPSTAT_AUTOXOFF)
751	uart_send_xchar(tty, STOP_CHAR(tty));
752
753	uart_port_deref(port);
754	}
755
756	static void uart_unthrottle(struct tty_struct *tty)
757	{
758	struct uart_state *state = tty->driver_data;
759	upstat_t mask = UPSTAT_SYNC_FIFO;
760	struct uart_port *port;
761
762	port = uart_port_ref(state);
763	if (!port)
764	return;
765
766	if (I_IXOFF(tty))
767	mask \|= UPSTAT_AUTOXOFF;
768	if (C_CRTSCTS(tty))
769	mask \|= UPSTAT_AUTORTS;
770
771	if (port->status & mask) {
772	port->ops->unthrottle(port);
773	mask &= ~port->status;
774	}
775
776	if (mask & UPSTAT_AUTORTS)
777	uart_set_mctrl(port, TIOCM_RTS);
778
779	if (mask & UPSTAT_AUTOXOFF)
780	uart_send_xchar(tty, START_CHAR(tty));
781
782	uart_port_deref(port);
783	}
784
785	static int uart_get_info(struct tty_port port, struct serial_struct retinfo)
786	{
787	struct uart_state *state = container_of(port, struct uart_state, port);
788	struct uart_port *uport;
789
790	/* Initialize structure in case we error out later to prevent any stack info leakage. */
791	*retinfo = (struct serial_struct){};
792
793	/*
794	* Ensure the state we copy is consistent and no hardware changes
795	* occur as we go
796	*/
797	guard(mutex)(&port->mutex);
798	uport = uart_port_check(state);
799	if (!uport)
800	return -ENODEV;
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	return 0;
822	}
823
824	static int uart_get_info_user(struct tty_struct *tty,
825	struct serial_struct *ss)
826	{
827	struct uart_state *state = tty->driver_data;
828	struct tty_port *port = &state->port;
829
830	return uart_get_info(port, ss) < 0 ? -EIO : 0;
831	}
832
833	static int uart_change_port(struct uart_port *uport,
834	const struct serial_struct *new_info,
835	unsigned long new_port)
836	{
837	unsigned long old_iobase, old_mapbase;
838	unsigned int old_type, old_iotype, old_hub6, old_shift;
839	int retval;
840
841	old_iobase = uport->iobase;
842	old_mapbase = uport->mapbase;
843	old_type = uport->type;
844	old_hub6 = uport->hub6;
845	old_iotype = uport->iotype;
846	old_shift = uport->regshift;
847
848	if (old_type != PORT_UNKNOWN && uport->ops->release_port)
849	uport->ops->release_port(uport);
850
851	uport->iobase = new_port;
852	uport->type = new_info->type;
853	uport->hub6 = new_info->hub6;
854	uport->iotype = new_info->io_type;
855	uport->regshift = new_info->iomem_reg_shift;
856	uport->mapbase = (unsigned long)new_info->iomem_base;
857
858	if (uport->type == PORT_UNKNOWN \|\| !uport->ops->request_port)
859	return 0;
860
861	retval = uport->ops->request_port(uport);
862	if (retval == 0)
863	return 0; /* succeeded => done */
864
865	/*
866	* If we fail to request resources for the new port, try to restore the
867	* old settings.
868	*/
869	uport->iobase = old_iobase;
870	uport->type = old_type;
871	uport->hub6 = old_hub6;
872	uport->iotype = old_iotype;
873	uport->regshift = old_shift;
874	uport->mapbase = old_mapbase;
875
876	if (old_type == PORT_UNKNOWN)
877	return retval;
878
879	retval = uport->ops->request_port(uport);
880	/* If we failed to restore the old settings, we fail like this. */
881	if (retval)
882	uport->type = PORT_UNKNOWN;
883
884	/* We failed anyway. */
885	return -EBUSY;
886	}
887
888	static int uart_set_info(struct tty_struct tty, struct tty_port port,
889	struct uart_state *state,
890	struct serial_struct *new_info)
891	{
892	struct uart_port *uport = uart_port_check(state);
893	unsigned long new_port;
894	unsigned int old_custom_divisor, close_delay, closing_wait;
895	bool change_irq, change_port;
896	upf_t old_flags, new_flags;
897	int retval;
898
899	if (!uport \|\| tty_io_error(tty))
900	return -EIO;
901
902	new_port = new_info->port;
903	if (HIGH_BITS_OFFSET)
904	new_port += (unsigned long) new_info->port_high << HIGH_BITS_OFFSET;
905
906	new_info->irq = irq_canonicalize(new_info->irq);
907	close_delay = msecs_to_jiffies(new_info->close_delay * 10);
908	closing_wait = new_info->closing_wait == ASYNC_CLOSING_WAIT_NONE ?
909	ASYNC_CLOSING_WAIT_NONE :
910	msecs_to_jiffies(new_info->closing_wait * 10);
911
912
913	change_irq = !(uport->flags & UPF_FIXED_PORT)
914	&& new_info->irq != uport->irq;
915
916	/*
917	* Since changing the 'type' of the port changes its resource
918	* allocations, we should treat type changes the same as
919	* IO port changes.
920	*/
921	change_port = !(uport->flags & UPF_FIXED_PORT)
922	&& (new_port != uport->iobase \|\|
923	(unsigned long)new_info->iomem_base != uport->mapbase \|\|
924	new_info->hub6 != uport->hub6 \|\|
925	new_info->io_type != uport->iotype \|\|
926	new_info->iomem_reg_shift != uport->regshift \|\|
927	new_info->type != uport->type);
928
929	old_flags = uport->flags;
930	new_flags = (__force upf_t)new_info->flags;
931	old_custom_divisor = uport->custom_divisor;
932
933	if (!(uport->flags & UPF_FIXED_PORT)) {
934	unsigned int uartclk = new_info->baud_base * 16;
935	/* check needs to be done here before other settings made */
936	if (uartclk == 0)
937	return -EINVAL;
938	}
939	if (!capable(CAP_SYS_ADMIN)) {
940	if (change_irq \|\| change_port \|\|
941	(new_info->baud_base != uport->uartclk / 16) \|\|
942	(close_delay != port->close_delay) \|\|
943	(closing_wait != port->closing_wait) \|\|
944	(new_info->xmit_fifo_size &&
945	new_info->xmit_fifo_size != uport->fifosize) \|\|
946	(((new_flags ^ old_flags) & ~UPF_USR_MASK) != 0))
947	return -EPERM;
948	uport->flags = ((uport->flags & ~UPF_USR_MASK) \|
949	(new_flags & UPF_USR_MASK));
950	uport->custom_divisor = new_info->custom_divisor;
951	goto check_and_exit;
952	}
953
954	if (change_irq \|\| change_port) {
955	retval = security_locked_down(LOCKDOWN_TIOCSSERIAL);
956	if (retval)
957	return retval;
958	}
959
960	/* Ask the low level driver to verify the settings. */
961	if (uport->ops->verify_port) {
962	retval = uport->ops->verify_port(uport, new_info);
963	if (retval)
964	return retval;
965	}
966
967	if ((new_info->irq >= irq_get_nr_irqs()) \|\| (new_info->irq < 0) \|\|
968	(new_info->baud_base < 9600))
969	return -EINVAL;
970
971	if (change_port \|\| change_irq) {
972	/* Make sure that we are the sole user of this port. */
973	if (tty_port_users(port) > 1)
974	return -EBUSY;
975
976	/*
977	* We need to shutdown the serial port at the old
978	* port/type/irq combination.
979	*/
980	uart_shutdown(tty, state);
981	}
982
983	if (change_port) {
984	retval = uart_change_port(uport, new_info, new_port);
985	if (retval)
986	return retval;
987	}
988
989	if (change_irq)
990	uport->irq = new_info->irq;
991	if (!(uport->flags & UPF_FIXED_PORT))
992	uport->uartclk = new_info->baud_base * 16;
993	uport->flags = (uport->flags & ~UPF_CHANGE_MASK) \|
994	(new_flags & UPF_CHANGE_MASK);
995	uport->custom_divisor = new_info->custom_divisor;
996	port->close_delay = close_delay;
997	port->closing_wait = closing_wait;
998	if (new_info->xmit_fifo_size)
999	uport->fifosize = new_info->xmit_fifo_size;
1000
1001	check_and_exit:
1002	if (uport->type == PORT_UNKNOWN)
1003	return 0;
1004
1005	if (tty_port_initialized(port)) {
1006	if (((old_flags ^ uport->flags) & UPF_SPD_MASK) \|\|
1007	old_custom_divisor != uport->custom_divisor) {
1008	/*
1009	* If they're setting up a custom divisor or speed,
1010	* instead of clearing it, then bitch about it.
1011	*/
1012	if (uport->flags & UPF_SPD_MASK) {
1013	dev_notice_ratelimited(uport->dev,
1014	"%s sets custom speed on %s. This is deprecated.\n",
1015	current->comm,
1016	tty_name(port->tty));
1017	}
1018	uart_change_line_settings(tty, state, NULL);
1019	}
1020
1021	return 0;
1022	}
1023
1024	retval = uart_startup(tty, state, true);
1025	if (retval < 0)
1026	return retval;
1027	if (retval == 0)
1028	tty_port_set_initialized(port, true);
1029
1030	return 0;
1031	}
1032
1033	static int uart_set_info_user(struct tty_struct tty, struct serial_struct ss)
1034	{
1035	struct uart_state *state = tty->driver_data;
1036	struct tty_port *port = &state->port;
1037
1038	guard(rwsem_write)(&tty->termios_rwsem);
1039	/*
1040	* This semaphore protects port->count. It is also
1041	* very useful to prevent opens. Also, take the
1042	* port configuration semaphore to make sure that a
1043	* module insertion/removal doesn't change anything
1044	* under us.
1045	*/
1046	guard(mutex)(&port->mutex);
1047	return uart_set_info(tty, port, state, ss);
1048	}
1049
1050	/**
1051	* uart_get_lsr_info - get line status register info
1052	* @tty: tty associated with the UART
1053	* @state: UART being queried
1054	* @value: returned modem value
1055	*/
1056	static int uart_get_lsr_info(struct tty_struct *tty,
1057	struct uart_state state, unsigned int __user value)
1058	{
1059	struct uart_port *uport = uart_port_check(state);
1060	unsigned int result;
1061
1062	result = uport->ops->tx_empty(uport);
1063
1064	/*
1065	* If we're about to load something into the transmit
1066	* register, we'll pretend the transmitter isn't empty to
1067	* avoid a race condition (depending on when the transmit
1068	* interrupt happens).
1069	*/
1070	if (uport->x_char \|\|
1071	(!kfifo_is_empty(&state->port.xmit_fifo) &&
1072	!uart_tx_stopped(uport)))
1073	result &= ~TIOCSER_TEMT;
1074
1075	return put_user(result, value);
1076	}
1077
1078	static int uart_tiocmget(struct tty_struct *tty)
1079	{
1080	struct uart_state *state = tty->driver_data;
1081	struct tty_port *port = &state->port;
1082	struct uart_port *uport;
1083
1084	guard(mutex)(&port->mutex);
1085
1086	uport = uart_port_check(state);
1087	if (!uport \|\| tty_io_error(tty))
1088	return -EIO;
1089
1090	guard(uart_port_lock_irq)(uport);
1091
1092	return uport->mctrl \| uport->ops->get_mctrl(uport);
1093	}
1094
1095	static int
1096	uart_tiocmset(struct tty_struct *tty, unsigned int set, unsigned int clear)
1097	{
1098	struct uart_state *state = tty->driver_data;
1099	struct tty_port *port = &state->port;
1100	struct uart_port *uport;
1101
1102	guard(mutex)(&port->mutex);
1103
1104	uport = uart_port_check(state);
1105	if (!uport \|\| tty_io_error(tty))
1106	return -EIO;
1107
1108	uart_update_mctrl(uport, set, clear);
1109
1110	return 0;
1111	}
1112
1113	static int uart_break_ctl(struct tty_struct *tty, int break_state)
1114	{
1115	struct uart_state *state = tty->driver_data;
1116	struct tty_port *port = &state->port;
1117	struct uart_port *uport;
1118
1119	guard(mutex)(&port->mutex);
1120
1121	uport = uart_port_check(state);
1122	if (!uport \|\| tty_io_error(tty))
1123	return -EIO;
1124
1125	if (uport->type != PORT_UNKNOWN && uport->ops->break_ctl)
1126	uport->ops->break_ctl(uport, break_state);
1127
1128	return 0;
1129	}
1130
1131	static int uart_do_autoconfig(struct tty_struct tty, struct uart_state state)
1132	{
1133	struct tty_port *port = &state->port;
1134	struct uart_port *uport;
1135	int flags, ret;
1136
1137	if (!capable(CAP_SYS_ADMIN))
1138	return -EPERM;
1139
1140	/*
1141	* Take the per-port semaphore. This prevents count from
1142	* changing, and hence any extra opens of the port while
1143	* we're auto-configuring.
1144	*/
1145	scoped_cond_guard(mutex_intr, return -ERESTARTSYS, &port->mutex) {
1146	uport = uart_port_check(state);
1147	if (!uport \|\| tty_io_error(tty))
1148	return -EIO;
1149
1150	if (tty_port_users(port) != 1)
1151	return -EBUSY;
1152
1153	uart_shutdown(tty, state);
1154
1155	/*
1156	* If we already have a port type configured,
1157	* we must release its resources.
1158	*/
1159	if (uport->type != PORT_UNKNOWN && uport->ops->release_port)
1160	uport->ops->release_port(uport);
1161
1162	flags = UART_CONFIG_TYPE;
1163	if (uport->flags & UPF_AUTO_IRQ)
1164	flags \|= UART_CONFIG_IRQ;
1165
1166	/*
1167	* This will claim the ports resources if
1168	* a port is found.
1169	*/
1170	uport->ops->config_port(uport, flags);
1171
1172	ret = uart_startup(tty, state, true);
1173	if (ret < 0)
1174	return ret;
1175	if (ret > 0)
1176	return 0;
1177
1178	tty_port_set_initialized(port, true);
1179	}
1180
1181	return 0;
1182	}
1183
1184	static void uart_enable_ms(struct uart_port *uport)
1185	{
1186	/*
1187	* Force modem status interrupts on
1188	*/
1189	if (uport->ops->enable_ms)
1190	uport->ops->enable_ms(uport);
1191	}
1192
1193	/*
1194	* Wait for any of the 4 modem inputs (DCD,RI,DSR,CTS) to change
1195	* - mask passed in arg for lines of interest
1196	* (use \|'ed TIOCM_RNG/DSR/CD/CTS for masking)
1197	* Caller should use TIOCGICOUNT to see which one it was
1198	*
1199	* FIXME: This wants extracting into a common all driver implementation
1200	* of TIOCMWAIT using tty_port.
1201	*/
1202	static int uart_wait_modem_status(struct tty_struct tty, struct uart_state state, unsigned long arg)
1203	{
1204	struct uart_port *uport;
1205	struct tty_port *port = &state->port;
1206	DECLARE_WAITQUEUE(wait, current);
1207	struct uart_icount cprev, cnow;
1208	int ret;
1209
1210	/*
1211	* note the counters on entry
1212	*/
1213	uport = uart_port_ref(state);
1214	if (!uport)
1215	return -EIO;
1216
1217	mutex_lock(&port->mutex);
1218	if (tty_io_error(tty)) {
1219	mutex_unlock(&port->mutex);
1220	ret = -EIO;
1221	goto out_deref;
1222	}
1223
1224	uart_port_lock_irq(uport);
1225	memcpy(&cprev, &uport->icount, sizeof(struct uart_icount));
1226	uart_enable_ms(uport);
1227	uart_port_unlock_irq(uport);
1228
1229	mutex_unlock(&port->mutex);
1230
1231	add_wait_queue(&port->delta_msr_wait, &wait);
1232	for (;;) {
1233	set_current_state(TASK_INTERRUPTIBLE);
1234
1235	uart_port_lock_irq(uport);
1236	memcpy(&cnow, &uport->icount, sizeof(struct uart_icount));
1237	uart_port_unlock_irq(uport);
1238
1239	if (((arg & TIOCM_RNG) && (cnow.rng != cprev.rng)) \|\|
1240	((arg & TIOCM_DSR) && (cnow.dsr != cprev.dsr)) \|\|
1241	((arg & TIOCM_CD) && (cnow.dcd != cprev.dcd)) \|\|
1242	((arg & TIOCM_CTS) && (cnow.cts != cprev.cts))) {
1243	ret = 0;
1244	break;
1245	}
1246
1247	if (tty_io_error(tty)) {
1248	ret = -EIO;
1249	break;
1250	}
1251
1252	schedule();
1253
1254	/* see if a signal did it */
1255	if (signal_pending(current)) {
1256	ret = -ERESTARTSYS;
1257	break;
1258	}
1259
1260	cprev = cnow;
1261	}
1262	__set_current_state(TASK_RUNNING);
1263	remove_wait_queue(&port->delta_msr_wait, &wait);
1264	out_deref:
1265	uart_port_deref(uport);
1266
1267	return ret;
1268	}
1269
1270	/*
1271	* Get counter of input serial line interrupts (DCD,RI,DSR,CTS)
1272	* Return: write counters to the user passed counter struct
1273	* NB: both 1->0 and 0->1 transitions are counted except for
1274	* RI where only 0->1 is counted.
1275	*/
1276	static int uart_get_icount(struct tty_struct *tty,
1277	struct serial_icounter_struct *icount)
1278	{
1279	struct uart_state *state = tty->driver_data;
1280	struct uart_icount cnow;
1281	struct uart_port *uport;
1282	unsigned long flags;
1283
1284	uport = uart_port_ref_lock(state, &flags);
1285	if (!uport)
1286	return -EIO;
1287	memcpy(&cnow, &uport->icount, sizeof(struct uart_icount));
1288	uart_port_unlock_deref(uport, flags);
1289
1290	icount->cts = cnow.cts;
1291	icount->dsr = cnow.dsr;
1292	icount->rng = cnow.rng;
1293	icount->dcd = cnow.dcd;
1294	icount->rx = cnow.rx;
1295	icount->tx = cnow.tx;
1296	icount->frame = cnow.frame;
1297	icount->overrun = cnow.overrun;
1298	icount->parity = cnow.parity;
1299	icount->brk = cnow.brk;
1300	icount->buf_overrun = cnow.buf_overrun;
1301
1302	return 0;
1303	}
1304
1305	#define SER_RS485_LEGACY_FLAGS (SER_RS485_ENABLED \| SER_RS485_RTS_ON_SEND \| \
1306	SER_RS485_RTS_AFTER_SEND \| SER_RS485_RX_DURING_TX \| \
1307	SER_RS485_TERMINATE_BUS)
1308
1309	static int uart_check_rs485_flags(struct uart_port port, struct serial_rs485 rs485)
1310	{
1311	u32 flags = rs485->flags;
1312
1313	/* Don't return -EINVAL for unsupported legacy flags */
1314	flags &= ~SER_RS485_LEGACY_FLAGS;
1315
1316	/*
1317	* For any bit outside of the legacy ones that is not supported by
1318	* the driver, return -EINVAL.
1319	*/
1320	if (flags & ~port->rs485_supported.flags)
1321	return -EINVAL;
1322
1323	/* Asking for address w/o addressing mode? */
1324	if (!(rs485->flags & SER_RS485_ADDRB) &&
1325	(rs485->flags & (SER_RS485_ADDR_RECV\|SER_RS485_ADDR_DEST)))
1326	return -EINVAL;
1327
1328	/* Address given but not enabled? */
1329	if (!(rs485->flags & SER_RS485_ADDR_RECV) && rs485->addr_recv)
1330	return -EINVAL;
1331	if (!(rs485->flags & SER_RS485_ADDR_DEST) && rs485->addr_dest)
1332	return -EINVAL;
1333
1334	return 0;
1335	}
1336
1337	static void uart_sanitize_serial_rs485_delays(struct uart_port *port,
1338	struct serial_rs485 *rs485)
1339	{
1340	if (!port->rs485_supported.delay_rts_before_send) {
1341	if (rs485->delay_rts_before_send) {
1342	dev_warn_ratelimited(port->dev,
1343	"%s (%u): RTS delay before sending not supported\n",
1344	port->name, port->line);
1345	}
1346	rs485->delay_rts_before_send = 0;
1347	} else if (rs485->delay_rts_before_send > RS485_MAX_RTS_DELAY) {
1348	rs485->delay_rts_before_send = RS485_MAX_RTS_DELAY;
1349	dev_warn_ratelimited(port->dev,
1350	"%s (%u): RTS delay before sending clamped to %u ms\n",
1351	port->name, port->line, rs485->delay_rts_before_send);
1352	}
1353
1354	if (!port->rs485_supported.delay_rts_after_send) {
1355	if (rs485->delay_rts_after_send) {
1356	dev_warn_ratelimited(port->dev,
1357	"%s (%u): RTS delay after sending not supported\n",
1358	port->name, port->line);
1359	}
1360	rs485->delay_rts_after_send = 0;
1361	} else if (rs485->delay_rts_after_send > RS485_MAX_RTS_DELAY) {
1362	rs485->delay_rts_after_send = RS485_MAX_RTS_DELAY;
1363	dev_warn_ratelimited(port->dev,
1364	"%s (%u): RTS delay after sending clamped to %u ms\n",
1365	port->name, port->line, rs485->delay_rts_after_send);
1366	}
1367	}
1368
1369	static void uart_sanitize_serial_rs485(struct uart_port port, struct serial_rs485 rs485)
1370	{
1371	u32 supported_flags = port->rs485_supported.flags;
1372
1373	if (!(rs485->flags & SER_RS485_ENABLED)) {
1374	memset(rs485, 0, sizeof(*rs485));
1375	return;
1376	}
1377
1378	/* Clear other RS485 flags but SER_RS485_TERMINATE_BUS and return if enabling RS422 */
1379	if (rs485->flags & SER_RS485_MODE_RS422) {
1380	rs485->flags &= (SER_RS485_ENABLED \| SER_RS485_MODE_RS422 \| SER_RS485_TERMINATE_BUS);
1381	return;
1382	}
1383
1384	rs485->flags &= supported_flags;
1385
1386	/* Pick sane settings if the user hasn't */
1387	if (!(rs485->flags & SER_RS485_RTS_ON_SEND) ==
1388	!(rs485->flags & SER_RS485_RTS_AFTER_SEND)) {
1389	if (supported_flags & SER_RS485_RTS_ON_SEND) {
1390	rs485->flags \|= SER_RS485_RTS_ON_SEND;
1391	rs485->flags &= ~SER_RS485_RTS_AFTER_SEND;
1392
1393	dev_warn_ratelimited(port->dev,
1394	"%s (%u): invalid RTS setting, using RTS_ON_SEND instead\n",
1395	port->name, port->line);
1396	} else {
1397	rs485->flags \|= SER_RS485_RTS_AFTER_SEND;
1398	rs485->flags &= ~SER_RS485_RTS_ON_SEND;
1399
1400	dev_warn_ratelimited(port->dev,
1401	"%s (%u): invalid RTS setting, using RTS_AFTER_SEND instead\n",
1402	port->name, port->line);
1403	}
1404	}
1405
1406	uart_sanitize_serial_rs485_delays(port, rs485);
1407
1408	/* Return clean padding area to userspace */
1409	memset(rs485->padding0, 0, sizeof(rs485->padding0));
1410	memset(rs485->padding1, 0, sizeof(rs485->padding1));
1411	}
1412
1413	static void uart_set_rs485_termination(struct uart_port *port,
1414	const struct serial_rs485 *rs485)
1415	{
1416	if (!(rs485->flags & SER_RS485_ENABLED))
1417	return;
1418
1419	gpiod_set_value_cansleep(port->rs485_term_gpio,
1420	!!(rs485->flags & SER_RS485_TERMINATE_BUS));
1421	}
1422
1423	static void uart_set_rs485_rx_during_tx(struct uart_port *port,
1424	const struct serial_rs485 *rs485)
1425	{
1426	if (!(rs485->flags & SER_RS485_ENABLED))
1427	return;
1428
1429	gpiod_set_value_cansleep(port->rs485_rx_during_tx_gpio,
1430	!!(rs485->flags & SER_RS485_RX_DURING_TX));
1431	}
1432
1433	static int uart_rs485_config(struct uart_port *port)
1434	{
1435	struct serial_rs485 *rs485 = &port->rs485;
1436	int ret;
1437
1438	if (!(rs485->flags & SER_RS485_ENABLED))
1439	return 0;
1440
1441	uart_sanitize_serial_rs485(port, rs485);
1442	uart_set_rs485_termination(port, rs485);
1443	uart_set_rs485_rx_during_tx(port, rs485);
1444
1445	scoped_guard(uart_port_lock_irqsave, port)
1446	ret = port->rs485_config(port, NULL, rs485);
1447	if (ret) {
1448	memset(rs485, 0, sizeof(*rs485));
1449	/* unset GPIOs */
1450	gpiod_set_value_cansleep(port->rs485_term_gpio, 0);
1451	gpiod_set_value_cansleep(port->rs485_rx_during_tx_gpio, 0);
1452	}
1453
1454	return ret;
1455	}
1456
1457	static int uart_get_rs485_config(struct uart_port *port,
1458	struct serial_rs485 __user *rs485)
1459	{
1460	struct serial_rs485 aux;
1461
1462	scoped_guard(uart_port_lock_irqsave, port)
1463	aux = port->rs485;
1464
1465	if (copy_to_user(rs485, &aux, sizeof(aux)))
1466	return -EFAULT;
1467
1468	return 0;
1469	}
1470
1471	static int uart_set_rs485_config(struct tty_struct tty, struct uart_port port,
1472	struct serial_rs485 __user *rs485_user)
1473	{
1474	struct serial_rs485 rs485;
1475	int ret;
1476
1477	if (!(port->rs485_supported.flags & SER_RS485_ENABLED))
1478	return -ENOTTY;
1479
1480	if (copy_from_user(&rs485, rs485_user, sizeof(*rs485_user)))
1481	return -EFAULT;
1482
1483	ret = uart_check_rs485_flags(port, &rs485);
1484	if (ret)
1485	return ret;
1486	uart_sanitize_serial_rs485(port, &rs485);
1487	uart_set_rs485_termination(port, &rs485);
1488	uart_set_rs485_rx_during_tx(port, &rs485);
1489
1490	scoped_guard(uart_port_lock_irqsave, port) {
1491	ret = port->rs485_config(port, &tty->termios, &rs485);
1492	if (!ret) {
1493	port->rs485 = rs485;
1494
1495	/* Reset RTS and other mctrl lines when disabling RS485 */
1496	if (!(rs485.flags & SER_RS485_ENABLED))
1497	port->ops->set_mctrl(port, port->mctrl);
1498	}
1499	}
1500	if (ret) {
1501	/* restore old GPIO settings */
1502	gpiod_set_value_cansleep(port->rs485_term_gpio,
1503	!!(port->rs485.flags & SER_RS485_TERMINATE_BUS));
1504	gpiod_set_value_cansleep(port->rs485_rx_during_tx_gpio,
1505	!!(port->rs485.flags & SER_RS485_RX_DURING_TX));
1506	return ret;
1507	}
1508
1509	if (copy_to_user(rs485_user, &port->rs485, sizeof(port->rs485)))
1510	return -EFAULT;
1511
1512	return 0;
1513	}
1514
1515	static int uart_get_iso7816_config(struct uart_port *port,
1516	struct serial_iso7816 __user *iso7816)
1517	{
1518	struct serial_iso7816 aux;
1519
1520	if (!port->iso7816_config)
1521	return -ENOTTY;
1522
1523	scoped_guard(uart_port_lock_irqsave, port)
1524	aux = port->iso7816;
1525
1526	if (copy_to_user(iso7816, &aux, sizeof(aux)))
1527	return -EFAULT;
1528
1529	return 0;
1530	}
1531
1532	static int uart_set_iso7816_config(struct uart_port *port,
1533	struct serial_iso7816 __user *iso7816_user)
1534	{
1535	struct serial_iso7816 iso7816;
1536	int i;
1537
1538	if (!port->iso7816_config)
1539	return -ENOTTY;
1540
1541	if (copy_from_user(&iso7816, iso7816_user, sizeof(*iso7816_user)))
1542	return -EFAULT;
1543
1544	/*
1545	* There are 5 words reserved for future use. Check that userspace
1546	* doesn't put stuff in there to prevent breakages in the future.
1547	*/
1548	for (i = 0; i < ARRAY_SIZE(iso7816.reserved); i++)
1549	if (iso7816.reserved[i])
1550	return -EINVAL;
1551
1552	scoped_guard(uart_port_lock_irqsave, port) {
1553	int ret = port->iso7816_config(port, &iso7816);
1554	if (ret)
1555	return ret;
1556	}
1557
1558	if (copy_to_user(iso7816_user, &port->iso7816, sizeof(port->iso7816)))
1559	return -EFAULT;
1560
1561	return 0;
1562	}
1563
1564	/*
1565	* Called via sys_ioctl. We can use spin_lock_irq() here.
1566	*/
1567	static int
1568	uart_ioctl(struct tty_struct *tty, unsigned int cmd, unsigned long arg)
1569	{
1570	struct uart_state *state = tty->driver_data;
1571	struct tty_port *port = &state->port;
1572	struct uart_port *uport;
1573	void __user uarg = (void __user )arg;
1574	int ret = -ENOIOCTLCMD;
1575
1576	/* This ioctl doesn't rely on the hardware to be present. */
1577	if (cmd == TIOCSERCONFIG) {
1578	guard(rwsem_write)(&tty->termios_rwsem);
1579	return uart_do_autoconfig(tty, state);
1580	}
1581
1582	if (tty_io_error(tty))
1583	return -EIO;
1584
1585	/* This should only be used when the hardware is present. */
1586	if (cmd == TIOCMIWAIT)
1587	return uart_wait_modem_status(tty, state, arg);
1588
1589	/* rs485_config requires more locking than others */
1590	if (cmd == TIOCSRS485)
1591	down_write(&tty->termios_rwsem);
1592
1593	scoped_guard(mutex, &port->mutex) {
1594	uport = uart_port_check(state);
1595
1596	if (!uport \|\| tty_io_error(tty)) {
1597	ret = -EIO;
1598	break;
1599	}
1600
1601	/*
1602	* All these rely on hardware being present and need to be
1603	* protected against the tty being hung up.
1604	*/
1605
1606	switch (cmd) {
1607	case TIOCSERGETLSR: /* Get line status register */
1608	ret = uart_get_lsr_info(tty, state, uarg);
1609	break;
1610
1611	case TIOCGRS485:
1612	ret = uart_get_rs485_config(uport, uarg);
1613	break;
1614
1615	case TIOCSRS485:
1616	ret = uart_set_rs485_config(tty, uport, uarg);
1617	break;
1618
1619	case TIOCSISO7816:
1620	ret = uart_set_iso7816_config(state->uart_port, uarg);
1621	break;
1622
1623	case TIOCGISO7816:
1624	ret = uart_get_iso7816_config(state->uart_port, uarg);
1625	break;
1626	default:
1627	if (uport->ops->ioctl)
1628	ret = uport->ops->ioctl(uport, cmd, arg);
1629	break;
1630	}
1631	}
1632
1633	if (cmd == TIOCSRS485)
1634	up_write(&tty->termios_rwsem);
1635
1636	return ret;
1637	}
1638
1639	static void uart_set_ldisc(struct tty_struct *tty)
1640	{
1641	struct uart_state *state = tty->driver_data;
1642	struct uart_port *uport;
1643
1644	guard(mutex)(&state->port.mutex);
1645	uport = uart_port_check(state);
1646	if (!uport \|\| tty_io_error(tty))
1647	return;
1648
1649	if (uport->ops->set_ldisc)
1650	uport->ops->set_ldisc(uport, &tty->termios);
1651	}
1652
1653	static void uart_set_termios(struct tty_struct *tty,
1654	const struct ktermios *old_termios)
1655	{
1656	struct uart_state *state = tty->driver_data;
1657	struct uart_port *uport;
1658	unsigned int cflag = tty->termios.c_cflag;
1659	unsigned int iflag_mask = IGNBRK\|BRKINT\|IGNPAR\|PARMRK\|INPCK;
1660	bool sw_changed = false;
1661
1662	guard(mutex)(&state->port.mutex);
1663
1664	uport = uart_port_check(state);
1665	if (!uport \|\| tty_io_error(tty))
1666	return;
1667
1668	/*
1669	* Drivers doing software flow control also need to know
1670	* about changes to these input settings.
1671	*/
1672	if (uport->flags & UPF_SOFT_FLOW) {
1673	iflag_mask \|= IXANY\|IXON\|IXOFF;
1674	sw_changed =
1675	tty->termios.c_cc[VSTART] != old_termios->c_cc[VSTART] \|\|
1676	tty->termios.c_cc[VSTOP] != old_termios->c_cc[VSTOP];
1677	}
1678
1679	/*
1680	* These are the bits that are used to setup various
1681	* flags in the low level driver. We can ignore the Bfoo
1682	* bits in c_cflag; c_[io]speed will always be set
1683	* appropriately by set_termios() in tty_ioctl.c
1684	*/
1685	if ((cflag ^ old_termios->c_cflag) == 0 &&
1686	tty->termios.c_ospeed == old_termios->c_ospeed &&
1687	tty->termios.c_ispeed == old_termios->c_ispeed &&
1688	((tty->termios.c_iflag ^ old_termios->c_iflag) & iflag_mask) == 0 &&
1689	!sw_changed)
1690	return;
1691
1692	uart_change_line_settings(tty, state, old_termios);
1693	/* reload cflag from termios; port driver may have overridden flags */
1694	cflag = tty->termios.c_cflag;
1695
1696	/* Handle transition to B0 status */
1697	if (((old_termios->c_cflag & CBAUD) != B0) && ((cflag & CBAUD) == B0))
1698	uart_clear_mctrl(uport, TIOCM_RTS \| TIOCM_DTR);
1699	/* Handle transition away from B0 status */
1700	else if (((old_termios->c_cflag & CBAUD) == B0) && ((cflag & CBAUD) != B0)) {
1701	unsigned int mask = TIOCM_DTR;
1702
1703	if (!(cflag & CRTSCTS) \|\| !tty_throttled(tty))
1704	mask \|= TIOCM_RTS;
1705	uart_set_mctrl(uport, mask);
1706	}
1707	}
1708
1709	/*
1710	* Calls to uart_close() are serialised via the tty_lock in
1711	* drivers/tty/tty_io.c:tty_release()
1712	* drivers/tty/tty_io.c:do_tty_hangup()
1713	*/
1714	static void uart_close(struct tty_struct tty, struct file filp)
1715	{
1716	struct uart_state *state = tty->driver_data;
1717
1718	if (!state) {
1719	struct uart_driver *drv = tty->driver->driver_state;
1720	struct tty_port *port;
1721
1722	state = drv->state + tty->index;
1723	port = &state->port;
1724	guard(spinlock_irq)(&port->lock);
1725	--port->count;
1726	return;
1727	}
1728
1729	pr_debug("uart_close(%d) called\n", tty->index);
1730
1731	tty_port_close(tty->port, tty, filp);
1732	}
1733
1734	static void uart_tty_port_shutdown(struct tty_port *port)
1735	{
1736	struct uart_state *state = container_of(port, struct uart_state, port);
1737	struct uart_port *uport = uart_port_check(state);
1738
1739	/*
1740	* At this point, we stop accepting input. To do this, we
1741	* disable the receive line status interrupts.
1742	*/
1743	if (WARN(!uport, "detached port still initialized!\n"))
1744	return;
1745
1746	scoped_guard(uart_port_lock_irq, uport)
1747	uport->ops->stop_rx(uport);
1748
1749	serial_base_port_shutdown(uport);
1750	uart_port_shutdown(port);
1751
1752	/*
1753	* It's possible for shutdown to be called after suspend if we get
1754	* a DCD drop (hangup) at just the right time. Clear suspended bit so
1755	* we don't try to resume a port that has been shutdown.
1756	*/
1757	tty_port_set_suspended(port, false);
1758
1759	uart_free_xmit_buf(port);
1760
1761	uart_change_pm(state, UART_PM_STATE_OFF);
1762	}
1763
1764	static void uart_wait_until_sent(struct tty_struct *tty, int timeout)
1765	{
1766	struct uart_state *state = tty->driver_data;
1767	struct uart_port *port;
1768	unsigned long char_time, expire, fifo_timeout;
1769
1770	port = uart_port_ref(state);
1771	if (!port)
1772	return;
1773
1774	if (port->type == PORT_UNKNOWN \|\| port->fifosize == 0) {
1775	uart_port_deref(port);
1776	return;
1777	}
1778
1779	/*
1780	* Set the check interval to be 1/5 of the estimated time to
1781	* send a single character, and make it at least 1. The check
1782	* interval should also be less than the timeout.
1783	*
1784	* Note: we have to use pretty tight timings here to satisfy
1785	* the NIST-PCTS.
1786	*/
1787	char_time = max(nsecs_to_jiffies(port->frame_time / 5), 1UL);
1788
1789	if (timeout && timeout < char_time)
1790	char_time = timeout;
1791
1792	if (!uart_cts_enabled(port)) {
1793	/*
1794	* If the transmitter hasn't cleared in twice the approximate
1795	* amount of time to send the entire FIFO, it probably won't
1796	* ever clear. This assumes the UART isn't doing flow
1797	* control, which is currently the case. Hence, if it ever
1798	* takes longer than FIFO timeout, this is probably due to a
1799	* UART bug of some kind. So, we clamp the timeout parameter at
1800	* 2 * FIFO timeout.
1801	*/
1802	fifo_timeout = uart_fifo_timeout(port);
1803	if (timeout == 0 \|\| timeout > 2 * fifo_timeout)
1804	timeout = 2 * fifo_timeout;
1805	}
1806
1807	expire = jiffies + timeout;
1808
1809	pr_debug("uart_wait_until_sent(%u), jiffies=%lu, expire=%lu...\n",
1810	port->line, jiffies, expire);
1811
1812	/*
1813	* Check whether the transmitter is empty every 'char_time'.
1814	* 'timeout' / 'expire' give us the maximum amount of time
1815	* we wait.
1816	*/
1817	for (;;) {
1818	mutex_lock(&state->port.mutex);
1819	if (tty_io_error(tty) \|\| port->ops->tx_empty(port)) {
1820	mutex_unlock(&state->port.mutex);
1821	break;
1822	}
1823	mutex_unlock(&state->port.mutex);
1824
1825	msleep_interruptible(jiffies_to_msecs(char_time));
1826	if (signal_pending(current))
1827	break;
1828	if (timeout && time_after(jiffies, expire))
1829	break;
1830	}
1831	uart_port_deref(port);
1832	}
1833
1834	/*
1835	* Calls to uart_hangup() are serialised by the tty_lock in
1836	* drivers/tty/tty_io.c:do_tty_hangup()
1837	* This runs from a workqueue and can sleep for a _short_ time only.
1838	*/
1839	static void uart_hangup(struct tty_struct *tty)
1840	{
1841	struct uart_state *state = tty->driver_data;
1842	struct tty_port *port = &state->port;
1843	struct uart_port *uport;
1844
1845	pr_debug("uart_hangup(%d)\n", tty->index);
1846
1847	guard(mutex)(&port->mutex);
1848	uport = uart_port_check(state);
1849	WARN(!uport, "hangup of detached port!\n");
1850
1851	if (tty_port_active(port)) {
1852	uart_flush_buffer(tty);
1853	uart_shutdown(tty, state);
1854	scoped_guard(spinlock_irqsave, &port->lock)
1855	port->count = 0;
1856	tty_port_set_active(port, false);
1857	tty_port_tty_set(port, NULL);
1858	if (uport && !uart_console(uport))
1859	uart_change_pm(state, UART_PM_STATE_OFF);
1860	wake_up_interruptible(&port->open_wait);
1861	wake_up_interruptible(&port->delta_msr_wait);
1862	}
1863	}
1864
1865	/* uport == NULL if uart_port has already been removed */
1866	static void uart_port_shutdown(struct tty_port *port)
1867	{
1868	struct uart_state *state = container_of(port, struct uart_state, port);
1869	struct uart_port *uport = uart_port_check(state);
1870
1871	/*
1872	* clear delta_msr_wait queue to avoid mem leaks: we may free
1873	* the irq here so the queue might never be woken up. Note
1874	* that we won't end up waiting on delta_msr_wait again since
1875	* any outstanding file descriptors should be pointing at
1876	* hung_up_tty_fops now.
1877	*/
1878	wake_up_interruptible(&port->delta_msr_wait);
1879
1880	if (uport) {
1881	/* Free the IRQ and disable the port. */
1882	uport->ops->shutdown(uport);
1883
1884	/* Ensure that the IRQ handler isn't running on another CPU. */
1885	synchronize_irq(uport->irq);
1886	}
1887	}
1888
1889	static bool uart_carrier_raised(struct tty_port *port)
1890	{
1891	struct uart_state *state = container_of(port, struct uart_state, port);
1892	struct uart_port *uport;
1893	unsigned long flags;
1894	int mctrl;
1895
1896	uport = uart_port_ref_lock(state, &flags);
1897	/*
1898	* Should never observe uport == NULL since checks for hangup should
1899	* abort the tty_port_block_til_ready() loop before checking for carrier
1900	* raised -- but report carrier raised if it does anyway so open will
1901	* continue and not sleep
1902	*/
1903	if (WARN_ON(!uport))
1904	return true;
1905	uart_enable_ms(uport);
1906	mctrl = uport->ops->get_mctrl(uport);
1907	uart_port_unlock_deref(uport, flags);
1908
1909	return mctrl & TIOCM_CAR;
1910	}
1911
1912	static void uart_dtr_rts(struct tty_port *port, bool active)
1913	{
1914	struct uart_state *state = container_of(port, struct uart_state, port);
1915	struct uart_port *uport;
1916
1917	uport = uart_port_ref(state);
1918	if (!uport)
1919	return;
1920	uart_port_dtr_rts(uport, active);
1921	uart_port_deref(uport);
1922	}
1923
1924	static int uart_install(struct tty_driver driver, struct tty_struct tty)
1925	{
1926	struct uart_driver *drv = driver->driver_state;
1927	struct uart_state *state = drv->state + tty->index;
1928
1929	tty->driver_data = state;
1930
1931	return tty_standard_install(driver, tty);
1932	}
1933
1934	/*
1935	* Calls to uart_open are serialised by the tty_lock in
1936	* drivers/tty/tty_io.c:tty_open()
1937	* Note that if this fails, then uart_close() _will_ be called.
1938	*
1939	* In time, we want to scrap the "opening nonpresent ports"
1940	* behaviour and implement an alternative way for setserial
1941	* to set base addresses/ports/types. This will allow us to
1942	* get rid of a certain amount of extra tests.
1943	*/
1944	static int uart_open(struct tty_struct tty, struct file filp)
1945	{
1946	struct uart_state *state = tty->driver_data;
1947	int retval;
1948
1949	retval = tty_port_open(&state->port, tty, filp);
1950	if (retval > 0)
1951	retval = 0;
1952
1953	return retval;
1954	}
1955
1956	static int uart_port_activate(struct tty_port port, struct tty_struct tty)
1957	{
1958	struct uart_state *state = container_of(port, struct uart_state, port);
1959	struct uart_port *uport;
1960	int ret;
1961
1962	uport = uart_port_check(state);
1963	if (!uport \|\| uport->flags & UPF_DEAD)
1964	return -ENXIO;
1965
1966	/*
1967	* Start up the serial port.
1968	*/
1969	ret = uart_startup(tty, state, false);
1970	if (ret > 0)
1971	tty_port_set_active(port, true);
1972
1973	return ret;
1974	}
1975
1976	static const char uart_type(struct uart_port port)
1977	{
1978	const char *str = NULL;
1979
1980	if (port->ops->type)
1981	str = port->ops->type(port);
1982
1983	if (!str)
1984	str = "unknown";
1985
1986	return str;
1987	}
1988
1989	bool uart_iotype_mmio(enum uart_iotype iotype)
1990	{
1991	switch (iotype) {
1992	case UPIO_MEM:
1993	case UPIO_MEM32:
1994	case UPIO_AU:
1995	case UPIO_TSI:
1996	case UPIO_MEM32BE:
1997	case UPIO_MEM16:
1998	return true;
1999	default:
2000	return false;
2001	}
2002	}
2003	EXPORT_SYMBOL_GPL(uart_iotype_mmio);
2004
2005	bool uart_iotype_io(enum uart_iotype iotype)
2006	{
2007	switch (iotype) {
2008	case UPIO_PORT:
2009	case UPIO_HUB6:
2010	return true;
2011	default:
2012	return false;
2013	}
2014	}
2015	EXPORT_SYMBOL_GPL(uart_iotype_io);
2016
2017	#ifdef CONFIG_PROC_FS
2018
2019	static void uart_line_info(struct seq_file m, struct uart_state state)
2020	{
2021	struct tty_port *port = &state->port;
2022	enum uart_pm_state pm_state;
2023	struct uart_port *uport;
2024	char ioinfos[64];
2025	char stat_buf[32];
2026	unsigned int status;
2027
2028	guard(mutex)(&port->mutex);
2029
2030	uport = uart_port_check(state);
2031	if (!uport)
2032	return;
2033
2034	seq_printf(m, "%u: uart:%s", uport->line, uart_type(uport));
2035	uart_get_ioinfos(uport, ioinfos, sizeof(ioinfos));
2036	seq_printf(m, "%s", ioinfos);
2037	seq_printf(m, " irq:%u", uport->irq);
2038
2039	if (uport->type == PORT_UNKNOWN) {
2040	seq_putc(m, '\n');
2041	return;
2042	}
2043
2044	if (capable(CAP_SYS_ADMIN)) {
2045	pm_state = state->pm_state;
2046	if (pm_state != UART_PM_STATE_ON)
2047	uart_change_pm(state, UART_PM_STATE_ON);
2048	scoped_guard(uart_port_lock_irq, uport)
2049	status = uport->ops->get_mctrl(uport);
2050	if (pm_state != UART_PM_STATE_ON)
2051	uart_change_pm(state, pm_state);
2052
2053	seq_printf(m, " tx:%u rx:%u",
2054	uport->icount.tx, uport->icount.rx);
2055	if (uport->icount.frame)
2056	seq_printf(m, " fe:%u", uport->icount.frame);
2057	if (uport->icount.parity)
2058	seq_printf(m, " pe:%u", uport->icount.parity);
2059	if (uport->icount.brk)
2060	seq_printf(m, " brk:%u", uport->icount.brk);
2061	if (uport->icount.overrun)
2062	seq_printf(m, " oe:%u", uport->icount.overrun);
2063	if (uport->icount.buf_overrun)
2064	seq_printf(m, " bo:%u", uport->icount.buf_overrun);
2065
2066	#define INFOBIT(bit, str) \
2067	if (uport->mctrl & (bit)) \
2068	strncat(stat_buf, (str), sizeof(stat_buf) - \
2069	strlen(stat_buf) - 2)
2070	#define STATBIT(bit, str) \
2071	if (status & (bit)) \
2072	strncat(stat_buf, (str), sizeof(stat_buf) - \
2073	strlen(stat_buf) - 2)
2074
2075	stat_buf[0] = '\0';
2076	stat_buf[1] = '\0';
2077	INFOBIT(TIOCM_RTS, "\|RTS");
2078	STATBIT(TIOCM_CTS, "\|CTS");
2079	INFOBIT(TIOCM_DTR, "\|DTR");
2080	STATBIT(TIOCM_DSR, "\|DSR");
2081	STATBIT(TIOCM_CAR, "\|CD");
2082	STATBIT(TIOCM_RNG, "\|RI");
2083	if (stat_buf[0])
2084	stat_buf[0] = ' ';
2085
2086	seq_puts(m, stat_buf);
2087	}
2088	seq_putc(m, '\n');
2089	#undef STATBIT
2090	#undef INFOBIT
2091	}
2092
2093	static int uart_proc_show(struct seq_file m, void v)
2094	{
2095	struct tty_driver *ttydrv = m->private;
2096	struct uart_driver *drv = ttydrv->driver_state;
2097	int i;
2098
2099	seq_printf(m, "serinfo:1.0 driver%s%s revision:%s\n", "", "", "");
2100	for (i = 0; i < drv->nr; i++)
2101	uart_line_info(m, drv->state + i);
2102	return 0;
2103	}
2104	#endif
2105
2106	static void uart_port_spin_lock_init(struct uart_port *port)
2107	{
2108	spin_lock_init(&port->lock);
2109	lockdep_set_class(&port->lock, &port_lock_key);
2110	}
2111
2112	#if defined(CONFIG_SERIAL_CORE_CONSOLE) \|\| defined(CONFIG_CONSOLE_POLL)
2113	/**
2114	* uart_console_write - write a console message to a serial port
2115	* @port: the port to write the message
2116	* @s: array of characters
2117	* @count: number of characters in string to write
2118	* @putchar: function to write character to port
2119	*/
2120	void uart_console_write(struct uart_port port, const char s,
2121	unsigned int count,
2122	void (putchar)(struct uart_port , unsigned char))
2123	{
2124	unsigned int i;
2125
2126	for (i = 0; i < count; i++, s++) {
2127	if (*s == '\n')
2128	putchar(port, '\r');
2129	putchar(port, *s);
2130	}
2131	}
2132	EXPORT_SYMBOL_GPL(uart_console_write);
2133
2134	/**
2135	* uart_parse_earlycon - Parse earlycon options
2136	* @p: ptr to 2nd field (ie., just beyond '<name>,')
2137	* @iotype: ptr for decoded iotype (out)
2138	* @addr: ptr for decoded mapbase/iobase (out)
2139	* @options: ptr for <options> field; %NULL if not present (out)
2140	*
2141	* Decodes earlycon kernel command line parameters of the form:
2142	* * earlycon=<name>,io\|mmio\|mmio16\|mmio32\|mmio32be\|mmio32native,<addr>,<options>
2143	* * console=<name>,io\|mmio\|mmio16\|mmio32\|mmio32be\|mmio32native,<addr>,<options>
2144	*
2145	* The optional form:
2146	* * earlycon=<name>,0x<addr>,<options>
2147	* * console=<name>,0x<addr>,<options>
2148	*
2149	* is also accepted; the returned @iotype will be %UPIO_MEM.
2150	*
2151	* Returns: 0 on success or -%EINVAL on failure
2152	*/
2153	int uart_parse_earlycon(char p, enum uart_iotype iotype,
2154	resource_size_t addr, char *options)
2155	{
2156	if (strncmp(p, "mmio,", 5) == 0) {
2157	*iotype = UPIO_MEM;
2158	p += 5;
2159	} else if (strncmp(p, "mmio16,", 7) == 0) {
2160	*iotype = UPIO_MEM16;
2161	p += 7;
2162	} else if (strncmp(p, "mmio32,", 7) == 0) {
2163	*iotype = UPIO_MEM32;
2164	p += 7;
2165	} else if (strncmp(p, "mmio32be,", 9) == 0) {
2166	*iotype = UPIO_MEM32BE;
2167	p += 9;
2168	} else if (strncmp(p, "mmio32native,", 13) == 0) {
2169	*iotype = IS_ENABLED(CONFIG_CPU_BIG_ENDIAN) ?
2170	UPIO_MEM32BE : UPIO_MEM32;
2171	p += 13;
2172	} else if (strncmp(p, "io,", 3) == 0) {
2173	*iotype = UPIO_PORT;
2174	p += 3;
2175	} else if (strncmp(p, "0x", 2) == 0) {
2176	*iotype = UPIO_MEM;
2177	} else {
2178	return -EINVAL;
2179	}
2180
2181	/*
2182	* Before you replace it with kstrtoull(), think about options separator
2183	* (',') it will not tolerate
2184	*/
2185	*addr = simple_strtoull(p, NULL, 0);
2186	p = strchr(p, ',');
2187	if (p)
2188	p++;
2189
2190	*options = p;
2191	return 0;
2192	}
2193	EXPORT_SYMBOL_GPL(uart_parse_earlycon);
2194
2195	/**
2196	* uart_parse_options - Parse serial port baud/parity/bits/flow control.
2197	* @options: pointer to option string
2198	* @baud: pointer to an 'int' variable for the baud rate.
2199	* @parity: pointer to an 'int' variable for the parity.
2200	* @bits: pointer to an 'int' variable for the number of data bits.
2201	* @flow: pointer to an 'int' variable for the flow control character.
2202	*
2203	* uart_parse_options() decodes a string containing the serial console
2204	* options. The format of the string is <baud><parity><bits><flow>,
2205	* eg: 115200n8r
2206	*/
2207	void
2208	uart_parse_options(const char options, int baud, int *parity,
2209	int bits, int flow)
2210	{
2211	const char *s = options;
2212
2213	*baud = simple_strtoul(s, NULL, 10);
2214	while (s >= '0' && s <= '9')
2215	s++;
2216	if (*s)
2217	parity = s++;
2218	if (*s)
2219	bits = s++ - '0';
2220	if (*s)
2221	flow = s;
2222	}
2223	EXPORT_SYMBOL_GPL(uart_parse_options);
2224
2225	/**
2226	* uart_set_options - setup the serial console parameters
2227	* @port: pointer to the serial ports uart_port structure
2228	* @co: console pointer
2229	* @baud: baud rate
2230	* @parity: parity character - 'n' (none), 'o' (odd), 'e' (even)
2231	* @bits: number of data bits
2232	* @flow: flow control character - 'r' (rts)
2233	*
2234	* Locking: Caller must hold console_list_lock in order to serialize
2235	* early initialization of the serial-console lock.
2236	*/
2237	int
2238	uart_set_options(struct uart_port port, struct console co,
2239	int baud, int parity, int bits, int flow)
2240	{
2241	struct ktermios termios;
2242	static struct ktermios dummy;
2243
2244	/*
2245	* Ensure that the serial-console lock is initialised early.
2246	*
2247	* Note that the console-registered check is needed because
2248	* kgdboc can call uart_set_options() for an already registered
2249	* console via tty_find_polling_driver() and uart_poll_init().
2250	*/
2251	if (!uart_console_registered_locked(port) && !port->console_reinit)
2252	uart_port_spin_lock_init(port);
2253
2254	memset(&termios, 0, sizeof(struct ktermios));
2255
2256	termios.c_cflag \|= CREAD \| HUPCL \| CLOCAL;
2257	tty_termios_encode_baud_rate(&termios, baud, baud);
2258
2259	if (bits == 7)
2260	termios.c_cflag \|= CS7;
2261	else
2262	termios.c_cflag \|= CS8;
2263
2264	switch (parity) {
2265	case 'o': case 'O':
2266	termios.c_cflag \|= PARODD;
2267	fallthrough;
2268	case 'e': case 'E':
2269	termios.c_cflag \|= PARENB;
2270	break;
2271	}
2272
2273	if (flow == 'r')
2274	termios.c_cflag \|= CRTSCTS;
2275
2276	/*
2277	* some uarts on other side don't support no flow control.
2278	* So we set * DTR in host uart to make them happy
2279	*/
2280	port->mctrl \|= TIOCM_DTR;
2281
2282	port->ops->set_termios(port, &termios, &dummy);
2283
2284	/*
2285	* If console hardware flow control was specified and is supported,
2286	* the related policy UPSTAT_CTS_ENABLE must be set to allow console
2287	* drivers to identify if CTS should be used for polling.
2288	*/
2289	if (flow == 'r' && (termios.c_cflag & CRTSCTS)) {
2290	/* Synchronize @status RMW update against the console. */
2291	guard(uart_port_lock_irqsave)(port);
2292	port->status \|= UPSTAT_CTS_ENABLE;
2293	}
2294
2295	/*
2296	* Allow the setting of the UART parameters with a NULL console
2297	* too:
2298	*/
2299	if (co) {
2300	co->cflag = termios.c_cflag;
2301	co->ispeed = termios.c_ispeed;
2302	co->ospeed = termios.c_ospeed;
2303	}
2304
2305	return 0;
2306	}
2307	EXPORT_SYMBOL_GPL(uart_set_options);
2308	#endif /* CONFIG_SERIAL_CORE_CONSOLE */
2309
2310	/**
2311	* uart_change_pm - set power state of the port
2312	*
2313	* @state: port descriptor
2314	* @pm_state: new state
2315	*
2316	* Locking: port->mutex has to be held
2317	*/
2318	static void uart_change_pm(struct uart_state *state,
2319	enum uart_pm_state pm_state)
2320	{
2321	struct uart_port *port = uart_port_check(state);
2322
2323	if (state->pm_state != pm_state) {
2324	if (port && port->ops->pm)
2325	port->ops->pm(port, pm_state, state->pm_state);
2326	state->pm_state = pm_state;
2327	}
2328	}
2329
2330	struct uart_match {
2331	struct uart_port *port;
2332	struct uart_driver *driver;
2333	};
2334
2335	static int serial_match_port(struct device dev, const void data)
2336	{
2337	const struct uart_match *match = data;
2338	struct tty_driver *tty_drv = match->driver->tty_driver;
2339	dev_t devt = MKDEV(tty_drv->major, tty_drv->minor_start) +
2340	match->port->line;
2341
2342	return dev->devt == devt; /* Actually, only one tty per port */
2343	}
2344
2345	int uart_suspend_port(struct uart_driver drv, struct uart_port uport)
2346	{
2347	struct uart_state *state = drv->state + uport->line;
2348	struct tty_port *port = &state->port;
2349	struct device *tty_dev;
2350	struct uart_match match = {uport, drv};
2351
2352	guard(mutex)(&port->mutex);
2353
2354	tty_dev = device_find_child(&uport->port_dev->dev, &match, serial_match_port);
2355	if (tty_dev && device_may_wakeup(tty_dev)) {
2356	enable_irq_wake(uport->irq);
2357	put_device(tty_dev);
2358	return 0;
2359	}
2360	put_device(tty_dev);
2361
2362	/*
2363	* Nothing to do if the console is not suspending
2364	* except stop_rx to prevent any asynchronous data
2365	* over RX line. However ensure that we will be
2366	* able to Re-start_rx later.
2367	*/
2368	if (!console_suspend_enabled && uart_console(uport)) {
2369	if (uport->ops->start_rx) {
2370	guard(uart_port_lock_irq)(uport);
2371	uport->ops->stop_rx(uport);
2372	}
2373	device_set_awake_path(uport->dev);
2374	return 0;
2375	}
2376
2377	uport->suspended = 1;
2378
2379	if (tty_port_initialized(port)) {
2380	const struct uart_ops *ops = uport->ops;
2381	int tries;
2382	unsigned int mctrl;
2383
2384	tty_port_set_suspended(port, true);
2385	tty_port_set_initialized(port, false);
2386
2387	scoped_guard(uart_port_lock_irq, uport) {
2388	ops->stop_tx(uport);
2389	if (!(uport->rs485.flags & SER_RS485_ENABLED))
2390	ops->set_mctrl(uport, 0);
2391	/* save mctrl so it can be restored on resume */
2392	mctrl = uport->mctrl;
2393	uport->mctrl = 0;
2394	ops->stop_rx(uport);
2395	}
2396
2397	/*
2398	* Wait for the transmitter to empty.
2399	*/
2400	for (tries = 3; !ops->tx_empty(uport) && tries; tries--)
2401	msleep(10);
2402	if (!tries)
2403	dev_err(uport->dev, "%s: Unable to drain transmitter\n",
2404	uport->name);
2405
2406	ops->shutdown(uport);
2407	uport->mctrl = mctrl;
2408	}
2409
2410	/*
2411	* Suspend the console device before suspending the port.
2412	*/
2413	if (uart_console(uport))
2414	console_suspend(uport->cons);
2415
2416	uart_change_pm(state, UART_PM_STATE_OFF);
2417
2418	return 0;
2419	}
2420	EXPORT_SYMBOL(uart_suspend_port);
2421
2422	int uart_resume_port(struct uart_driver drv, struct uart_port uport)
2423	{
2424	struct uart_state *state = drv->state + uport->line;
2425	struct tty_port *port = &state->port;
2426	struct device *tty_dev;
2427	struct uart_match match = {uport, drv};
2428	struct ktermios termios;
2429
2430	guard(mutex)(&port->mutex);
2431
2432	tty_dev = device_find_child(&uport->port_dev->dev, &match, serial_match_port);
2433	if (!uport->suspended && device_may_wakeup(tty_dev)) {
2434	if (irqd_is_wakeup_set(irq_get_irq_data((uport->irq))))
2435	disable_irq_wake(uport->irq);
2436	put_device(tty_dev);
2437	return 0;
2438	}
2439	put_device(tty_dev);
2440	uport->suspended = 0;
2441
2442	/*
2443	* Re-enable the console device after suspending.
2444	*/
2445	if (uart_console(uport)) {
2446	/*
2447	* First try to use the console cflag setting.
2448	*/
2449	memset(&termios, 0, sizeof(struct ktermios));
2450	termios.c_cflag = uport->cons->cflag;
2451	termios.c_ispeed = uport->cons->ispeed;
2452	termios.c_ospeed = uport->cons->ospeed;
2453
2454	/*
2455	* If that's unset, use the tty termios setting.
2456	*/
2457	if (port->tty && termios.c_cflag == 0)
2458	termios = port->tty->termios;
2459
2460	if (console_suspend_enabled)
2461	uart_change_pm(state, UART_PM_STATE_ON);
2462	uport->ops->set_termios(uport, &termios, NULL);
2463	if (!console_suspend_enabled && uport->ops->start_rx) {
2464	guard(uart_port_lock_irq)(uport);
2465	uport->ops->start_rx(uport);
2466	}
2467	if (console_suspend_enabled)
2468	console_resume(uport->cons);
2469	}
2470
2471	if (tty_port_suspended(port)) {
2472	const struct uart_ops *ops = uport->ops;
2473	int ret;
2474
2475	uart_change_pm(state, UART_PM_STATE_ON);
2476	scoped_guard(uart_port_lock_irq, uport)
2477	if (!(uport->rs485.flags & SER_RS485_ENABLED))
2478	ops->set_mctrl(uport, 0);
2479	if (console_suspend_enabled \|\| !uart_console(uport)) {
2480	/* Protected by port mutex for now */
2481	struct tty_struct *tty = port->tty;
2482
2483	ret = ops->startup(uport);
2484	if (ret == 0) {
2485	if (tty)
2486	uart_change_line_settings(tty, state, NULL);
2487	uart_rs485_config(uport);
2488	scoped_guard(uart_port_lock_irq, uport) {
2489	if (!(uport->rs485.flags & SER_RS485_ENABLED))
2490	ops->set_mctrl(uport, uport->mctrl);
2491	ops->start_tx(uport);
2492	}
2493	tty_port_set_initialized(port, true);
2494	} else {
2495	/*
2496	* Failed to resume - maybe hardware went away?
2497	* Clear the "initialized" flag so we won't try
2498	* to call the low level drivers shutdown method.
2499	*/
2500	uart_shutdown(tty, state);
2501	}
2502	}
2503
2504	tty_port_set_suspended(port, false);
2505	}
2506
2507	return 0;
2508	}
2509	EXPORT_SYMBOL(uart_resume_port);
2510
2511	static const char uart_get_mmio_width(struct uart_port port)
2512	{
2513	switch (port->iotype) {
2514	case UPIO_MEM16:
2515	return "16";
2516	case UPIO_MEM32:
2517	case UPIO_MEM32BE:
2518	return "32";
2519	case UPIO_AU:
2520	case UPIO_MEM:
2521	default:
2522	return "";
2523	}
2524	}
2525
2526	void uart_get_ioinfos(struct uart_port port, char buf, size_t size)
2527	{
2528	buf[0] = '\0';
2529
2530	if (uart_iotype_mmio(port->iotype)) {
2531	scnprintf(buf, size, " MMIO%s:%pa", uart_get_mmio_width(port), &port->mapbase);
2532	} else if (uart_iotype_io(port->iotype)) {
2533	if (port->iotype == UPIO_PORT)
2534	scnprintf(buf, size, " I/O:0x%lx", port->iobase);
2535	else if (port->iotype == UPIO_HUB6)
2536	scnprintf(buf, size, " I/O:0x%lx, offset 0x%x", port->iobase, port->hub6);
2537	}
2538	}
2539	EXPORT_SYMBOL(uart_get_ioinfos);
2540
2541	static inline void
2542	uart_report_port(struct uart_driver drv, struct uart_port port)
2543	{
2544	char ioinfos[64];
2545
2546	uart_get_ioinfos(port, ioinfos, sizeof(ioinfos));
2547
2548	pr_info("%s%s%s%s (irq = %u, base_baud = %u) is a %s\n",
2549	port->dev ? dev_name(port->dev) : "",
2550	port->dev ? ": " : "",
2551	port->name, ioinfos, port->irq, port->uartclk / 16, uart_type(port));
2552
2553	/* The magic multiplier feature is a bit obscure, so report it too. */
2554	if (port->flags & UPF_MAGIC_MULTIPLIER)
2555	pr_info("%s%s%s extra baud rates supported: %u, %u",
2556	port->dev ? dev_name(port->dev) : "",
2557	port->dev ? ": " : "",
2558	port->name,
2559	port->uartclk / 8, port->uartclk / 4);
2560	}
2561
2562	static void
2563	uart_configure_port(struct uart_driver drv, struct uart_state state,
2564	struct uart_port *port)
2565	{
2566	unsigned int flags;
2567
2568	/* If there isn't a port here, don't do anything further. */
2569	if (uart_iotype_mmio(port->iotype) \|\| uart_iotype_io(port->iotype))
2570	if (!port->iobase && !port->mapbase && !port->membase)
2571	return;
2572
2573	/*
2574	* Now do the auto configuration stuff. Note that config_port
2575	* is expected to claim the resources and map the port for us.
2576	*/
2577	flags = 0;
2578	if (port->flags & UPF_AUTO_IRQ)
2579	flags \|= UART_CONFIG_IRQ;
2580	if (port->flags & UPF_BOOT_AUTOCONF) {
2581	if (!(port->flags & UPF_FIXED_TYPE)) {
2582	port->type = PORT_UNKNOWN;
2583	flags \|= UART_CONFIG_TYPE;
2584	}
2585	/* Synchronize with possible boot console. */
2586	if (uart_console(port))
2587	console_lock();
2588	port->ops->config_port(port, flags);
2589	if (uart_console(port))
2590	console_unlock();
2591	}
2592
2593	if (port->type != PORT_UNKNOWN) {
2594	uart_report_port(drv, port);
2595
2596	/* Synchronize with possible boot console. */
2597	if (uart_console(port))
2598	console_lock();
2599
2600	/* Power up port for set_mctrl() */
2601	uart_change_pm(state, UART_PM_STATE_ON);
2602
2603	/*
2604	* Ensure that the modem control lines are de-activated.
2605	* keep the DTR setting that is set in uart_set_options()
2606	* We probably don't need a spinlock around this, but
2607	*/
2608	scoped_guard(uart_port_lock_irqsave, port) {
2609	unsigned int mask = TIOCM_DTR;
2610
2611	/* Console hardware flow control polls CTS. */
2612	if (uart_console_hwflow_active(port))
2613	mask \|= TIOCM_RTS;
2614
2615	port->mctrl &= mask;
2616
2617	if (!(port->rs485.flags & SER_RS485_ENABLED))
2618	port->ops->set_mctrl(port, port->mctrl);
2619	}
2620
2621	uart_rs485_config(port);
2622
2623	if (uart_console(port))
2624	console_unlock();
2625
2626	/*
2627	* If this driver supports console, and it hasn't been
2628	* successfully registered yet, try to re-register it.
2629	* It may be that the port was not available.
2630	*/
2631	if (port->cons && !console_is_registered(port->cons))
2632	register_console(port->cons);
2633
2634	/*
2635	* Power down all ports by default, except the
2636	* console if we have one.
2637	*/
2638	if (!uart_console(port))
2639	uart_change_pm(state, UART_PM_STATE_OFF);
2640	}
2641	}
2642
2643	#ifdef CONFIG_CONSOLE_POLL
2644
2645	static int uart_poll_init(struct tty_driver driver, int line, char options)
2646	{
2647	struct uart_driver *drv = driver->driver_state;
2648	struct uart_state *state = drv->state + line;
2649	enum uart_pm_state pm_state;
2650	struct tty_port *tport;
2651	struct uart_port *port;
2652	int baud = 9600;
2653	int bits = 8;
2654	int parity = 'n';
2655	int flow = 'n';
2656	int ret = 0;
2657
2658	tport = &state->port;
2659
2660	guard(mutex)(&tport->mutex);
2661
2662	port = uart_port_check(state);
2663	if (!port \|\| port->type == PORT_UNKNOWN \|\|
2664	!(port->ops->poll_get_char && port->ops->poll_put_char))
2665	return -1;
2666
2667	pm_state = state->pm_state;
2668	uart_change_pm(state, UART_PM_STATE_ON);
2669
2670	if (port->ops->poll_init) {
2671	/*
2672	* We don't set initialized as we only initialized the hw,
2673	* e.g. state->xmit is still uninitialized.
2674	*/
2675	if (!tty_port_initialized(tport))
2676	ret = port->ops->poll_init(port);
2677	}
2678
2679	if (!ret && options) {
2680	uart_parse_options(options, &baud, &parity, &bits, &flow);
2681	console_list_lock();
2682	ret = uart_set_options(port, NULL, baud, parity, bits, flow);
2683	console_list_unlock();
2684	}
2685
2686	if (ret)
2687	uart_change_pm(state, pm_state);
2688
2689	return ret;
2690	}
2691
2692	static int uart_poll_get_char(struct tty_driver *driver, int line)
2693	{
2694	struct uart_driver *drv = driver->driver_state;
2695	struct uart_state *state = drv->state + line;
2696	struct uart_port *port;
2697	int ret = -1;
2698
2699	port = uart_port_ref(state);
2700	if (port) {
2701	ret = port->ops->poll_get_char(port);
2702	uart_port_deref(port);
2703	}
2704
2705	return ret;
2706	}
2707
2708	static void uart_poll_put_char(struct tty_driver *driver, int line, char ch)
2709	{
2710	struct uart_driver *drv = driver->driver_state;
2711	struct uart_state *state = drv->state + line;
2712	struct uart_port *port;
2713
2714	port = uart_port_ref(state);
2715	if (!port)
2716	return;
2717
2718	if (ch == '\n')
2719	port->ops->poll_put_char(port, '\r');
2720	port->ops->poll_put_char(port, ch);
2721	uart_port_deref(port);
2722	}
2723	#endif
2724
2725	static const struct tty_operations uart_ops = {
2726	.install = uart_install,
2727	.open = uart_open,
2728	.close = uart_close,
2729	.write = uart_write,
2730	.put_char = uart_put_char,
2731	.flush_chars = uart_flush_chars,
2732	.write_room = uart_write_room,
2733	.chars_in_buffer= uart_chars_in_buffer,
2734	.flush_buffer = uart_flush_buffer,
2735	.ioctl = uart_ioctl,
2736	.throttle = uart_throttle,
2737	.unthrottle = uart_unthrottle,
2738	.send_xchar = uart_send_xchar,
2739	.set_termios = uart_set_termios,
2740	.set_ldisc = uart_set_ldisc,
2741	.stop = uart_stop,
2742	.start = uart_start,
2743	.hangup = uart_hangup,
2744	.break_ctl = uart_break_ctl,
2745	.wait_until_sent= uart_wait_until_sent,
2746	#ifdef CONFIG_PROC_FS
2747	.proc_show = uart_proc_show,
2748	#endif
2749	.tiocmget = uart_tiocmget,
2750	.tiocmset = uart_tiocmset,
2751	.set_serial = uart_set_info_user,
2752	.get_serial = uart_get_info_user,
2753	.get_icount = uart_get_icount,
2754	#ifdef CONFIG_CONSOLE_POLL
2755	.poll_init = uart_poll_init,
2756	.poll_get_char = uart_poll_get_char,
2757	.poll_put_char = uart_poll_put_char,
2758	#endif
2759	};
2760
2761	static const struct tty_port_operations uart_port_ops = {
2762	.carrier_raised = uart_carrier_raised,
2763	.dtr_rts = uart_dtr_rts,
2764	.activate = uart_port_activate,
2765	.shutdown = uart_tty_port_shutdown,
2766	};
2767
2768	/**
2769	* uart_register_driver - register a driver with the uart core layer
2770	* @drv: low level driver structure
2771	*
2772	* Register a uart driver with the core driver. We in turn register with the
2773	* tty layer, and initialise the core driver per-port state.
2774	*
2775	* We have a proc file in /proc/tty/driver which is named after the normal
2776	* driver.
2777	*
2778	* @drv->port should be %NULL, and the per-port structures should be registered
2779	* using uart_add_one_port() after this call has succeeded.
2780	*
2781	* Locking: none, Interrupts: enabled
2782	*/
2783	int uart_register_driver(struct uart_driver *drv)
2784	{
2785	struct tty_driver *normal;
2786	int i, retval = -ENOMEM;
2787
2788	BUG_ON(drv->state);
2789
2790	/*
2791	* Maybe we should be using a slab cache for this, especially if
2792	* we have a large number of ports to handle.
2793	*/
2794	drv->state = kzalloc_objs(struct uart_state, drv->nr);
2795	if (!drv->state)
2796	goto out;
2797
2798	normal = tty_alloc_driver(drv->nr, TTY_DRIVER_REAL_RAW \|
2799	TTY_DRIVER_DYNAMIC_DEV);
2800	if (IS_ERR(normal)) {
2801	retval = PTR_ERR(normal);
2802	goto out_kfree;
2803	}
2804
2805	drv->tty_driver = normal;
2806
2807	normal->driver_name = drv->driver_name;
2808	normal->name = drv->dev_name;
2809	normal->major = drv->major;
2810	normal->minor_start = drv->minor;
2811	normal->type = TTY_DRIVER_TYPE_SERIAL;
2812	normal->subtype = SERIAL_TYPE_NORMAL;
2813	normal->init_termios = tty_std_termios;
2814	normal->init_termios.c_cflag = B9600 \| CS8 \| CREAD \| HUPCL \| CLOCAL;
2815	normal->init_termios.c_ispeed = normal->init_termios.c_ospeed = 9600;
2816	normal->driver_state = drv;
2817	tty_set_operations(normal, &uart_ops);
2818
2819	/*
2820	* Initialise the UART state(s).
2821	*/
2822	for (i = 0; i < drv->nr; i++) {
2823	struct uart_state *state = drv->state + i;
2824	struct tty_port *port = &state->port;
2825
2826	tty_port_init(port);
2827	port->ops = &uart_port_ops;
2828	}
2829
2830	retval = tty_register_driver(normal);
2831	if (retval >= 0)
2832	return retval;
2833
2834	for (i = 0; i < drv->nr; i++)
2835	tty_port_destroy(&drv->state[i].port);
2836	tty_driver_kref_put(normal);
2837	drv->tty_driver = NULL;
2838	out_kfree:
2839	kfree(drv->state);
2840	drv->state = NULL;
2841	out:
2842	return retval;
2843	}
2844	EXPORT_SYMBOL(uart_register_driver);
2845
2846	/**
2847	* uart_unregister_driver - remove a driver from the uart core layer
2848	* @drv: low level driver structure
2849	*
2850	* Remove all references to a driver from the core driver. The low level
2851	* driver must have removed all its ports via the uart_remove_one_port() if it
2852	* registered them with uart_add_one_port(). (I.e. @drv->port is %NULL.)
2853	*
2854	* Locking: none, Interrupts: enabled
2855	*/
2856	void uart_unregister_driver(struct uart_driver *drv)
2857	{
2858	struct tty_driver *p = drv->tty_driver;
2859	unsigned int i;
2860
2861	tty_unregister_driver(p);
2862	tty_driver_kref_put(p);
2863	for (i = 0; i < drv->nr; i++)
2864	tty_port_destroy(&drv->state[i].port);
2865	kfree(drv->state);
2866	drv->state = NULL;
2867	drv->tty_driver = NULL;
2868	}
2869	EXPORT_SYMBOL(uart_unregister_driver);
2870
2871	struct tty_driver uart_console_device(struct console co, int *index)
2872	{
2873	struct uart_driver *p = co->data;
2874	*index = co->index;
2875	return p->tty_driver;
2876	}
2877	EXPORT_SYMBOL_GPL(uart_console_device);
2878
2879	static ssize_t uartclk_show(struct device *dev,
2880	struct device_attribute attr, char buf)
2881	{
2882	struct serial_struct tmp;
2883	struct tty_port *port = dev_get_drvdata(dev);
2884
2885	uart_get_info(port, &tmp);
2886	return sprintf(buf, "%d\n", tmp.baud_base * 16);
2887	}
2888
2889	static ssize_t type_show(struct device *dev,
2890	struct device_attribute attr, char buf)
2891	{
2892	struct serial_struct tmp;
2893	struct tty_port *port = dev_get_drvdata(dev);
2894
2895	uart_get_info(port, &tmp);
2896	return sprintf(buf, "%d\n", tmp.type);
2897	}
2898
2899	static ssize_t line_show(struct device *dev,
2900	struct device_attribute attr, char buf)
2901	{
2902	struct serial_struct tmp;
2903	struct tty_port *port = dev_get_drvdata(dev);
2904
2905	uart_get_info(port, &tmp);
2906	return sprintf(buf, "%d\n", tmp.line);
2907	}
2908
2909	static ssize_t port_show(struct device *dev,
2910	struct device_attribute attr, char buf)
2911	{
2912	struct serial_struct tmp;
2913	struct tty_port *port = dev_get_drvdata(dev);
2914	unsigned long ioaddr;
2915
2916	uart_get_info(port, &tmp);
2917	ioaddr = tmp.port;
2918	if (HIGH_BITS_OFFSET)
2919	ioaddr \|= (unsigned long)tmp.port_high << HIGH_BITS_OFFSET;
2920	return sprintf(buf, "0x%lX\n", ioaddr);
2921	}
2922
2923	static ssize_t irq_show(struct device *dev,
2924	struct device_attribute attr, char buf)
2925	{
2926	struct serial_struct tmp;
2927	struct tty_port *port = dev_get_drvdata(dev);
2928
2929	uart_get_info(port, &tmp);
2930	return sprintf(buf, "%d\n", tmp.irq);
2931	}
2932
2933	static ssize_t flags_show(struct device *dev,
2934	struct device_attribute attr, char buf)
2935	{
2936	struct serial_struct tmp;
2937	struct tty_port *port = dev_get_drvdata(dev);
2938
2939	uart_get_info(port, &tmp);
2940	return sprintf(buf, "0x%X\n", tmp.flags);
2941	}
2942
2943	static ssize_t xmit_fifo_size_show(struct device *dev,
2944	struct device_attribute attr, char buf)
2945	{
2946	struct serial_struct tmp;
2947	struct tty_port *port = dev_get_drvdata(dev);
2948
2949	uart_get_info(port, &tmp);
2950	return sprintf(buf, "%d\n", tmp.xmit_fifo_size);
2951	}
2952
2953	static ssize_t close_delay_show(struct device *dev,
2954	struct device_attribute attr, char buf)
2955	{
2956	struct serial_struct tmp;
2957	struct tty_port *port = dev_get_drvdata(dev);
2958
2959	uart_get_info(port, &tmp);
2960	return sprintf(buf, "%u\n", tmp.close_delay);
2961	}
2962
2963	static ssize_t closing_wait_show(struct device *dev,
2964	struct device_attribute attr, char buf)
2965	{
2966	struct serial_struct tmp;
2967	struct tty_port *port = dev_get_drvdata(dev);
2968
2969	uart_get_info(port, &tmp);
2970	return sprintf(buf, "%u\n", tmp.closing_wait);
2971	}
2972
2973	static ssize_t custom_divisor_show(struct device *dev,
2974	struct device_attribute attr, char buf)
2975	{
2976	struct serial_struct tmp;
2977	struct tty_port *port = dev_get_drvdata(dev);
2978
2979	uart_get_info(port, &tmp);
2980	return sprintf(buf, "%d\n", tmp.custom_divisor);
2981	}
2982
2983	static ssize_t io_type_show(struct device *dev,
2984	struct device_attribute attr, char buf)
2985	{
2986	struct serial_struct tmp;
2987	struct tty_port *port = dev_get_drvdata(dev);
2988
2989	uart_get_info(port, &tmp);
2990	return sprintf(buf, "%u\n", tmp.io_type);
2991	}
2992
2993	static ssize_t iomem_base_show(struct device *dev,
2994	struct device_attribute attr, char buf)
2995	{
2996	struct serial_struct tmp;
2997	struct tty_port *port = dev_get_drvdata(dev);
2998
2999	uart_get_info(port, &tmp);
3000	return sprintf(buf, "0x%lX\n", (unsigned long)tmp.iomem_base);
3001	}
3002
3003	static ssize_t iomem_reg_shift_show(struct device *dev,
3004	struct device_attribute attr, char buf)
3005	{
3006	struct serial_struct tmp;
3007	struct tty_port *port = dev_get_drvdata(dev);
3008
3009	uart_get_info(port, &tmp);
3010	return sprintf(buf, "%u\n", tmp.iomem_reg_shift);
3011	}
3012
3013	static ssize_t console_show(struct device *dev,
3014	struct device_attribute attr, char buf)
3015	{
3016	struct tty_port *port = dev_get_drvdata(dev);
3017	struct uart_state *state = container_of(port, struct uart_state, port);
3018	struct uart_port *uport;
3019	bool console = false;
3020
3021	scoped_guard(mutex, &port->mutex) {
3022	uport = uart_port_check(state);
3023	if (uport)
3024	console = uart_console_registered(uport);
3025	}
3026
3027	return sprintf(buf, "%c\n", console ? 'Y' : 'N');
3028	}
3029
3030	static ssize_t console_store(struct device *dev,
3031	struct device_attribute attr, const char buf, size_t count)
3032	{
3033	struct tty_port *port = dev_get_drvdata(dev);
3034	struct uart_state *state = container_of(port, struct uart_state, port);
3035	struct uart_port *uport;
3036	bool oldconsole, newconsole;
3037	int ret;
3038
3039	ret = kstrtobool(buf, &newconsole);
3040	if (ret)
3041	return ret;
3042
3043	guard(mutex)(&port->mutex);
3044	uport = uart_port_check(state);
3045	if (!uport)
3046	return -ENXIO;
3047
3048	oldconsole = uart_console_registered(uport);
3049	if (oldconsole && !newconsole) {
3050	ret = unregister_console(uport->cons);
3051	if (ret < 0)
3052	return ret;
3053	} else if (!oldconsole && newconsole) {
3054	if (!uart_console(uport))
3055	return -ENOENT;
3056
3057	uport->console_reinit = 1;
3058	register_console(uport->cons);
3059	}
3060
3061	return count;
3062	}
3063
3064	static DEVICE_ATTR_RO(uartclk);
3065	static DEVICE_ATTR_RO(type);
3066	static DEVICE_ATTR_RO(line);
3067	static DEVICE_ATTR_RO(port);
3068	static DEVICE_ATTR_RO(irq);
3069	static DEVICE_ATTR_RO(flags);
3070	static DEVICE_ATTR_RO(xmit_fifo_size);
3071	static DEVICE_ATTR_RO(close_delay);
3072	static DEVICE_ATTR_RO(closing_wait);
3073	static DEVICE_ATTR_RO(custom_divisor);
3074	static DEVICE_ATTR_RO(io_type);
3075	static DEVICE_ATTR_RO(iomem_base);
3076	static DEVICE_ATTR_RO(iomem_reg_shift);
3077	static DEVICE_ATTR_RW(console);
3078
3079	static struct attribute *tty_dev_attrs[] = {
3080	&dev_attr_uartclk.attr,
3081	&dev_attr_type.attr,
3082	&dev_attr_line.attr,
3083	&dev_attr_port.attr,
3084	&dev_attr_irq.attr,
3085	&dev_attr_flags.attr,
3086	&dev_attr_xmit_fifo_size.attr,
3087	&dev_attr_close_delay.attr,
3088	&dev_attr_closing_wait.attr,
3089	&dev_attr_custom_divisor.attr,
3090	&dev_attr_io_type.attr,
3091	&dev_attr_iomem_base.attr,
3092	&dev_attr_iomem_reg_shift.attr,
3093	&dev_attr_console.attr,
3094	NULL
3095	};
3096
3097	static const struct attribute_group tty_dev_attr_group = {
3098	.attrs = tty_dev_attrs,
3099	};
3100
3101	/**
3102	* serial_core_add_one_port - attach a driver-defined port structure
3103	* @drv: pointer to the uart low level driver structure for this port
3104	* @uport: uart port structure to use for this port.
3105	*
3106	* Context: task context, might sleep
3107	*
3108	* This allows the driver @drv to register its own uart_port structure with the
3109	* core driver. The main purpose is to allow the low level uart drivers to
3110	* expand uart_port, rather than having yet more levels of structures.
3111	* Caller must hold port_mutex.
3112	*/
3113	static int serial_core_add_one_port(struct uart_driver drv, struct uart_port uport)
3114	{
3115	struct uart_state *state;
3116	struct tty_port *port;
3117	struct device *tty_dev;
3118
3119	if (uport->line >= drv->nr)
3120	return -EINVAL;
3121
3122	state = drv->state + uport->line;
3123	port = &state->port;
3124
3125	guard(mutex)(&port->mutex);
3126	if (state->uart_port)
3127	return -EINVAL;
3128
3129	uport->name = kasprintf(GFP_KERNEL, "%s%u", drv->dev_name,
3130	drv->tty_driver->name_base + uport->line);
3131	if (!uport->name)
3132	return -ENOMEM;
3133
3134	/*
3135	* uart_configure_port() may set uport->attr_group and register the
3136	* console. Allocate room for both groups and a NULL terminator first.
3137	*/
3138	uport->tty_groups = kzalloc_objs(*uport->tty_groups, 3);
3139	if (!uport->tty_groups) {
3140	kfree(uport->name);
3141	return -ENOMEM;
3142	}
3143	uport->tty_groups[0] = &tty_dev_attr_group;
3144
3145	/* Link the port to the driver state table and vice versa */
3146	atomic_set(&state->refcount, 1);
3147	init_waitqueue_head(&state->remove_wait);
3148	state->uart_port = uport;
3149	uport->state = state;
3150
3151	/*
3152	* If this port is in use as a console then the spinlock is already
3153	* initialised.
3154	*/
3155	if (!uart_console_registered(uport))
3156	uart_port_spin_lock_init(uport);
3157
3158	state->pm_state = UART_PM_STATE_UNDEFINED;
3159	uart_port_set_cons(uport, drv->cons);
3160	uport->minor = drv->tty_driver->minor_start + uport->line;
3161
3162	if (uport->cons && uport->dev)
3163	of_console_check(uport->dev->of_node, uport->cons->name, uport->line);
3164
3165	/*
3166	* TTY port has to be linked with the driver before register_console()
3167	* in uart_configure_port(), because user-space could open the console
3168	* immediately after.
3169	*/
3170	tty_port_link_device(port, drv->tty_driver, uport->line);
3171	uart_configure_port(drv, state, uport);
3172
3173	port->console = uart_console(uport);
3174
3175	if (uport->attr_group)
3176	uport->tty_groups[1] = uport->attr_group;
3177
3178	/* Ensure serdev drivers can call serdev_device_open() right away */
3179	uport->flags &= ~UPF_DEAD;
3180
3181	/*
3182	* Register the port whether it's detected or not. This allows
3183	* setserial to be used to alter this port's parameters.
3184	*/
3185	tty_dev = tty_port_register_device_attr_serdev(port, drv->tty_driver,
3186	uport->line, uport->dev, &uport->port_dev->dev, port,
3187	uport->tty_groups);
3188	if (!IS_ERR(tty_dev)) {
3189	device_set_wakeup_capable(tty_dev, 1);
3190	} else {
3191	uport->flags \|= UPF_DEAD;
3192	dev_err(uport->dev, "Cannot register tty device on line %u\n",
3193	uport->line);
3194	}
3195
3196	return 0;
3197	}
3198
3199	/**
3200	* serial_core_remove_one_port - detach a driver defined port structure
3201	* @drv: pointer to the uart low level driver structure for this port
3202	* @uport: uart port structure for this port
3203	*
3204	* Context: task context, might sleep
3205	*
3206	* This unhooks (and hangs up) the specified port structure from the core
3207	* driver. No further calls will be made to the low-level code for this port.
3208	* Caller must hold port_mutex.
3209	*/
3210	static void serial_core_remove_one_port(struct uart_driver *drv,
3211	struct uart_port *uport)
3212	{
3213	struct uart_state *state = drv->state + uport->line;
3214	struct tty_port *port = &state->port;
3215	struct uart_port *uart_port;
3216
3217	scoped_guard(mutex, &port->mutex) {
3218	uart_port = uart_port_check(state);
3219	if (uart_port != uport)
3220	dev_alert(uport->dev, "Removing wrong port: %p != %p\n", uart_port, uport);
3221
3222	if (!uart_port)
3223	return;
3224	}
3225
3226	/*
3227	* Remove the devices from the tty layer
3228	*/
3229	tty_port_unregister_device(port, drv->tty_driver, uport->line);
3230
3231	tty_port_tty_vhangup(port);
3232
3233	/*
3234	* If the port is used as a console, unregister it
3235	*/
3236	if (uart_console(uport))
3237	unregister_console(uport->cons);
3238
3239	/*
3240	* Free the port IO and memory resources, if any.
3241	*/
3242	if (uport->type != PORT_UNKNOWN && uport->ops->release_port)
3243	uport->ops->release_port(uport);
3244	kfree(uport->tty_groups);
3245	kfree(uport->name);
3246
3247	/*
3248	* Indicate that there isn't a port here anymore.
3249	*/
3250	uport->type = PORT_UNKNOWN;
3251	uport->port_dev = NULL;
3252
3253	guard(mutex)(&port->mutex);
3254	WARN_ON(atomic_dec_return(&state->refcount) < 0);
3255	wait_event(state->remove_wait, !atomic_read(&state->refcount));
3256	state->uart_port = NULL;
3257	}
3258
3259	/**
3260	* uart_match_port - are the two ports equivalent?
3261	* @port1: first port
3262	* @port2: second port
3263	*
3264	* This utility function can be used to determine whether two uart_port
3265	* structures describe the same port.
3266	*/
3267	bool uart_match_port(const struct uart_port *port1,
3268	const struct uart_port *port2)
3269	{
3270	if (port1->iotype != port2->iotype)
3271	return false;
3272	else if (port1->iotype == UPIO_PORT)
3273	return port1->iobase == port2->iobase;
3274	else if (port1->iotype == UPIO_HUB6)
3275	return hub6_match_port(port1, port2);
3276	else if (uart_iotype_mmio(port1->iotype))
3277	return port1->mapbase == port2->mapbase;
3278	else if (port1->iotype == UPIO_BUS)
3279	return true;
3280	else
3281	return false;
3282	}
3283	EXPORT_SYMBOL(uart_match_port);
3284
3285	static struct serial_ctrl_device *
3286	serial_core_get_ctrl_dev(struct serial_port_device *port_dev)
3287	{
3288	struct device *dev = &port_dev->dev;
3289
3290	return to_serial_base_ctrl_device(dev->parent);
3291	}
3292
3293	/*
3294	* Find a registered serial core controller device if one exists. Returns
3295	* the first device matching the ctrl_id. Caller must hold port_mutex.
3296	*/
3297	static struct serial_ctrl_device serial_core_ctrl_find(struct uart_driver drv,
3298	struct device *phys_dev,
3299	int ctrl_id)
3300	{
3301	struct uart_state *state;
3302	int i;
3303
3304	lockdep_assert_held(&port_mutex);
3305
3306	for (i = 0; i < drv->nr; i++) {
3307	state = drv->state + i;
3308	if (!state->uart_port \|\| !state->uart_port->port_dev)
3309	continue;
3310
3311	if (state->uart_port->dev == phys_dev &&
3312	state->uart_port->ctrl_id == ctrl_id)
3313	return serial_core_get_ctrl_dev(state->uart_port->port_dev);
3314	}
3315
3316	return NULL;
3317	}
3318
3319	static struct serial_ctrl_device serial_core_ctrl_device_add(struct uart_port port)
3320	{
3321	return serial_base_ctrl_add(port, port->dev);
3322	}
3323
3324	static int serial_core_port_device_add(struct serial_ctrl_device *ctrl_dev,
3325	struct uart_port *port)
3326	{
3327	struct serial_port_device *port_dev;
3328
3329	port_dev = serial_base_port_add(port, ctrl_dev);
3330	if (IS_ERR(port_dev))
3331	return PTR_ERR(port_dev);
3332
3333	port->port_dev = port_dev;
3334
3335	return 0;
3336	}
3337
3338	/*
3339	* Initialize a serial core port device, and a controller device if needed.
3340	*/
3341	int serial_core_register_port(struct uart_driver drv, struct uart_port port)
3342	{
3343	struct serial_ctrl_device ctrl_dev, new_ctrl_dev = NULL;
3344	int ret;
3345
3346	guard(mutex)(&port_mutex);
3347
3348	/*
3349	* Prevent serial_port_runtime_resume() from trying to use the port
3350	* until serial_core_add_one_port() has completed
3351	*/
3352	port->flags \|= UPF_DEAD;
3353
3354	/* Inititalize a serial core controller device if needed */
3355	ctrl_dev = serial_core_ctrl_find(drv, port->dev, port->ctrl_id);
3356	if (!ctrl_dev) {
3357	new_ctrl_dev = serial_core_ctrl_device_add(port);
3358	if (IS_ERR(new_ctrl_dev))
3359	return PTR_ERR(new_ctrl_dev);
3360	ctrl_dev = new_ctrl_dev;
3361	}
3362
3363	/*
3364	* Initialize a serial core port device. Tag the port dead to prevent
3365	* serial_port_runtime_resume() trying to do anything until port has
3366	* been registered. It gets cleared by serial_core_add_one_port().
3367	*/
3368	ret = serial_core_port_device_add(ctrl_dev, port);
3369	if (ret)
3370	goto err_unregister_ctrl_dev;
3371
3372	ret = serial_base_match_and_update_preferred_console(drv, port);
3373	if (ret)
3374	goto err_unregister_port_dev;
3375
3376	ret = serial_core_add_one_port(drv, port);
3377	if (ret)
3378	goto err_unregister_port_dev;
3379
3380	return 0;
3381
3382	err_unregister_port_dev:
3383	serial_base_port_device_remove(port->port_dev);
3384	port->port_dev = NULL;
3385
3386	err_unregister_ctrl_dev:
3387	serial_base_ctrl_device_remove(new_ctrl_dev);
3388
3389	return ret;
3390	}
3391
3392	/*
3393	* Removes a serial core port device, and the related serial core controller
3394	* device if the last instance.
3395	*/
3396	void serial_core_unregister_port(struct uart_driver drv, struct uart_port port)
3397	{
3398	struct device *phys_dev = port->dev;
3399	struct serial_port_device *port_dev;
3400	struct serial_ctrl_device *ctrl_dev;
3401	int ctrl_id = port->ctrl_id;
3402
3403	guard(mutex)(&port_mutex);
3404
3405	/*
3406	* A NULL port device means there is no registered port device to
3407	* remove: serial_core_remove_one_port() clears port_dev on
3408	* teardown, and it is never set if registration failed before
3409	* serial_core_port_device_add().
3410	*/
3411	port_dev = port->port_dev;
3412	if (!port_dev)
3413	return;
3414
3415	ctrl_dev = serial_core_get_ctrl_dev(port_dev);
3416
3417	port->flags \|= UPF_DEAD;
3418
3419	serial_core_remove_one_port(drv, port);
3420
3421	/* Note that struct uart_port port is no longer valid at this point /
3422	serial_base_port_device_remove(port_dev);
3423
3424	/* Drop the serial core controller device if no ports are using it */
3425	if (!serial_core_ctrl_find(drv, phys_dev, ctrl_id))
3426	serial_base_ctrl_device_remove(ctrl_dev);
3427	}
3428
3429	/**
3430	* uart_handle_dcd_change - handle a change of carrier detect state
3431	* @uport: uart_port structure for the open port
3432	* @active: new carrier detect status
3433	*
3434	* Caller must hold uport->lock.
3435	*/
3436	void uart_handle_dcd_change(struct uart_port *uport, bool active)
3437	{
3438	struct tty_port *port = &uport->state->port;
3439	struct tty_struct *tty = port->tty;
3440	struct tty_ldisc *ld;
3441
3442	lockdep_assert_held_once(&uport->lock);
3443
3444	if (tty) {
3445	ld = tty_ldisc_ref(tty);
3446	if (ld) {
3447	if (ld->ops->dcd_change)
3448	ld->ops->dcd_change(tty, active);
3449	tty_ldisc_deref(ld);
3450	}
3451	}
3452
3453	uport->icount.dcd++;
3454
3455	if (uart_dcd_enabled(uport)) {
3456	if (active)
3457	wake_up_interruptible(&port->open_wait);
3458	else if (tty)
3459	tty_hangup(tty);
3460	}
3461	}
3462	EXPORT_SYMBOL_GPL(uart_handle_dcd_change);
3463
3464	/**
3465	* uart_handle_cts_change - handle a change of clear-to-send state
3466	* @uport: uart_port structure for the open port
3467	* @active: new clear-to-send status
3468	*
3469	* Caller must hold uport->lock.
3470	*/
3471	void uart_handle_cts_change(struct uart_port *uport, bool active)
3472	{
3473	lockdep_assert_held_once(&uport->lock);
3474
3475	uport->icount.cts++;
3476
3477	if (uart_softcts_mode(uport)) {
3478	if (uport->hw_stopped) {
3479	if (active) {
3480	uport->hw_stopped = false;
3481	uport->ops->start_tx(uport);
3482	uart_write_wakeup(uport);
3483	}
3484	} else {
3485	if (!active) {
3486	uport->hw_stopped = true;
3487	uport->ops->stop_tx(uport);
3488	}
3489	}
3490
3491	}
3492	}
3493	EXPORT_SYMBOL_GPL(uart_handle_cts_change);
3494
3495	/**
3496	* uart_insert_char - push a char to the uart layer
3497	*
3498	* User is responsible to call tty_flip_buffer_push when they are done with
3499	* insertion.
3500	*
3501	* @port: corresponding port
3502	* @status: state of the serial port RX buffer (LSR for 8250)
3503	* @overrun: mask of overrun bits in @status
3504	* @ch: character to push
3505	* @flag: flag for the character (see TTY_NORMAL and friends)
3506	*/
3507	void uart_insert_char(struct uart_port *port, unsigned int status,
3508	unsigned int overrun, u8 ch, u8 flag)
3509	{
3510	struct tty_port *tport = &port->state->port;
3511
3512	if ((status & port->ignore_status_mask & ~overrun) == 0)
3513	if (tty_insert_flip_char(tport, ch, flag) == 0)
3514	++port->icount.buf_overrun;
3515
3516	/*
3517	* Overrun is special. Since it's reported immediately,
3518	* it doesn't affect the current character.
3519	*/
3520	if (status & ~port->ignore_status_mask & overrun)
3521	if (tty_insert_flip_char(tport, 0, TTY_OVERRUN) == 0)
3522	++port->icount.buf_overrun;
3523	}
3524	EXPORT_SYMBOL_GPL(uart_insert_char);
3525
3526	#ifdef CONFIG_MAGIC_SYSRQ_SERIAL
3527	static const u8 sysrq_toggle_seq[] = CONFIG_MAGIC_SYSRQ_SERIAL_SEQUENCE;
3528
3529	static void uart_sysrq_on(struct work_struct *w)
3530	{
3531	int sysrq_toggle_seq_len = strlen(sysrq_toggle_seq);
3532
3533	sysrq_toggle_support(1);
3534	pr_info("SysRq is enabled by magic sequence '%*pE' on serial\n",
3535	sysrq_toggle_seq_len, sysrq_toggle_seq);
3536	}
3537	static DECLARE_WORK(sysrq_enable_work, uart_sysrq_on);
3538
3539	/**
3540	* uart_try_toggle_sysrq - Enables SysRq from serial line
3541	* @port: uart_port structure where char(s) after BREAK met
3542	* @ch: new character in the sequence after received BREAK
3543	*
3544	* Enables magic SysRq when the required sequence is met on port
3545	* (see CONFIG_MAGIC_SYSRQ_SERIAL_SEQUENCE).
3546	*
3547	* Returns: %false if @ch is out of enabling sequence and should be
3548	* handled some other way, %true if @ch was consumed.
3549	*/
3550	bool uart_try_toggle_sysrq(struct uart_port *port, u8 ch)
3551	{
3552	int sysrq_toggle_seq_len = strlen(sysrq_toggle_seq);
3553
3554	if (!sysrq_toggle_seq_len)
3555	return false;
3556
3557	BUILD_BUG_ON(ARRAY_SIZE(sysrq_toggle_seq) >= U8_MAX);
3558	if (sysrq_toggle_seq[port->sysrq_seq] != ch) {
3559	port->sysrq_seq = 0;
3560	return false;
3561	}
3562
3563	if (++port->sysrq_seq < sysrq_toggle_seq_len) {
3564	port->sysrq = jiffies + SYSRQ_TIMEOUT;
3565	return true;
3566	}
3567
3568	schedule_work(&sysrq_enable_work);
3569
3570	port->sysrq = 0;
3571	return true;
3572	}
3573	EXPORT_SYMBOL_GPL(uart_try_toggle_sysrq);
3574	#endif
3575
3576	/**
3577	* uart_get_rs485_mode() - retrieve rs485 properties for given uart
3578	* @port: uart device's target port
3579	*
3580	* This function implements the device tree binding described in
3581	* Documentation/devicetree/bindings/serial/rs485.yaml.
3582	*/
3583	int uart_get_rs485_mode(struct uart_port *port)
3584	{
3585	struct serial_rs485 *rs485conf = &port->rs485;
3586	struct device *dev = port->dev;
3587	enum gpiod_flags dflags;
3588	struct gpio_desc *desc;
3589	u32 rs485_delay[2];
3590	int ret;
3591
3592	if (!(port->rs485_supported.flags & SER_RS485_ENABLED))
3593	return 0;
3594
3595	/*
3596	* Retrieve properties only if a firmware node exists. If no firmware
3597	* node exists, then don't touch rs485 config and keep initial rs485
3598	* properties set by driver.
3599	*/
3600	if (!dev_fwnode(dev))
3601	return 0;
3602
3603	ret = device_property_read_u32_array(dev, "rs485-rts-delay",
3604	rs485_delay, 2);
3605	if (!ret) {
3606	rs485conf->delay_rts_before_send = rs485_delay[0];
3607	rs485conf->delay_rts_after_send = rs485_delay[1];
3608	} else {
3609	rs485conf->delay_rts_before_send = 0;
3610	rs485conf->delay_rts_after_send = 0;
3611	}
3612
3613	uart_sanitize_serial_rs485_delays(port, rs485conf);
3614
3615	/*
3616	* Clear full-duplex and enabled flags, set RTS polarity to active high
3617	* to get to a defined state with the following properties:
3618	*/
3619	rs485conf->flags &= ~(SER_RS485_RX_DURING_TX \| SER_RS485_ENABLED \|
3620	SER_RS485_TERMINATE_BUS \|
3621	SER_RS485_RTS_AFTER_SEND);
3622	rs485conf->flags \|= SER_RS485_RTS_ON_SEND;
3623
3624	if (device_property_read_bool(dev, "rs485-rx-during-tx"))
3625	rs485conf->flags \|= SER_RS485_RX_DURING_TX;
3626
3627	if (device_property_read_bool(dev, "linux,rs485-enabled-at-boot-time"))
3628	rs485conf->flags \|= SER_RS485_ENABLED;
3629
3630	if (device_property_read_bool(dev, "rs485-rts-active-low")) {
3631	rs485conf->flags &= ~SER_RS485_RTS_ON_SEND;
3632	rs485conf->flags \|= SER_RS485_RTS_AFTER_SEND;
3633	}
3634
3635	/*
3636	* Disabling termination by default is the safe choice: Else if many
3637	* bus participants enable it, no communication is possible at all.
3638	* Works fine for short cables and users may enable for longer cables.
3639	*/
3640	desc = devm_gpiod_get_optional(dev, "rs485-term", GPIOD_OUT_LOW);
3641	if (IS_ERR(desc))
3642	return dev_err_probe(dev, PTR_ERR(desc), "Cannot get rs485-term-gpios\n");
3643	port->rs485_term_gpio = desc;
3644	if (port->rs485_term_gpio)
3645	port->rs485_supported.flags \|= SER_RS485_TERMINATE_BUS;
3646
3647	dflags = (rs485conf->flags & SER_RS485_RX_DURING_TX) ?
3648	GPIOD_OUT_HIGH : GPIOD_OUT_LOW;
3649	desc = devm_gpiod_get_optional(dev, "rs485-rx-during-tx", dflags);
3650	if (IS_ERR(desc))
3651	return dev_err_probe(dev, PTR_ERR(desc), "Cannot get rs485-rx-during-tx-gpios\n");
3652	port->rs485_rx_during_tx_gpio = desc;
3653	if (port->rs485_rx_during_tx_gpio)
3654	port->rs485_supported.flags \|= SER_RS485_RX_DURING_TX;
3655
3656	return 0;
3657	}
3658	EXPORT_SYMBOL_GPL(uart_get_rs485_mode);
3659
3660	/* Compile-time assertions for serial_rs485 layout */
3661	static_assert(offsetof(struct serial_rs485, padding) ==
3662	(offsetof(struct serial_rs485, delay_rts_after_send) + sizeof(__u32)));
3663	static_assert(offsetof(struct serial_rs485, padding1) ==
3664	offsetof(struct serial_rs485, padding[1]));
3665	static_assert((offsetof(struct serial_rs485, padding[4]) + sizeof(__u32)) ==
3666	sizeof(struct serial_rs485));
3667
3668	MODULE_DESCRIPTION("Serial driver core");
3669	MODULE_LICENSE("GPL");