1 // SPDX-License-Identifier: GPL-2.0+
2 /*
3  *  Universal/legacy driver for 8250/16550-type serial ports
4  *
5  *  Based on drivers/char/serial.c, by Linus Torvalds, Theodore Ts'o.
6  *
7  *  Copyright (C) 2001 Russell King.
8  *
9  *  Supports: ISA-compatible 8250/16550 ports
10  *	      PNP 8250/16550 ports
11  *	      early_serial_setup() ports
12  *	      userspace-configurable "phantom" ports
13  *	      "serial8250" platform devices
14  *	      serial8250_register_8250_port() ports
15  */
16 
17 #include <linux/acpi.h>
18 #include <linux/module.h>
19 #include <linux/moduleparam.h>
20 #include <linux/ioport.h>
21 #include <linux/init.h>
22 #include <linux/console.h>
23 #include <linux/sysrq.h>
24 #include <linux/delay.h>
25 #include <linux/platform_device.h>
26 #include <linux/pm_runtime.h>
27 #include <linux/tty.h>
28 #include <linux/ratelimit.h>
29 #include <linux/tty_flip.h>
30 #include <linux/serial.h>
31 #include <linux/serial_8250.h>
32 #include <linux/nmi.h>
33 #include <linux/mutex.h>
34 #include <linux/slab.h>
35 #include <linux/uaccess.h>
36 #include <linux/io.h>
37 #ifdef CONFIG_SPARC
38 #include <linux/sunserialcore.h>
39 #endif
40 
41 #include <asm/irq.h>
42 
43 #include "8250.h"
44 
45 /*
46  * Configuration:
47  *   share_irqs - whether we pass IRQF_SHARED to request_irq().  This option
48  *                is unsafe when used on edge-triggered interrupts.
49  */
50 static unsigned int share_irqs = SERIAL8250_SHARE_IRQS;
51 
52 static unsigned int nr_uarts = CONFIG_SERIAL_8250_RUNTIME_UARTS;
53 
54 static struct uart_driver serial8250_reg;
55 
56 static unsigned int skip_txen_test; /* force skip of txen test at init time */
57 
58 #define PASS_LIMIT	512
59 
60 #include <asm/serial.h>
61 /*
62  * SERIAL_PORT_DFNS tells us about built-in ports that have no
63  * standard enumeration mechanism.   Platforms that can find all
64  * serial ports via mechanisms like ACPI or PCI need not supply it.
65  */
66 #ifndef SERIAL_PORT_DFNS
67 #define SERIAL_PORT_DFNS
68 #endif
69 
70 static const struct old_serial_port old_serial_port[] = {
71 	SERIAL_PORT_DFNS /* defined in asm/serial.h */
72 };
73 
74 #define UART_NR	CONFIG_SERIAL_8250_NR_UARTS
75 
76 #ifdef CONFIG_SERIAL_8250_RSA
77 
78 #define PORT_RSA_MAX 4
79 static unsigned long probe_rsa[PORT_RSA_MAX];
80 static unsigned int probe_rsa_count;
81 #endif /* CONFIG_SERIAL_8250_RSA  */
82 
83 struct irq_info {
84 	struct			hlist_node node;
85 	int			irq;
86 	spinlock_t		lock;	/* Protects list not the hash */
87 	struct list_head	*head;
88 };
89 
90 #define NR_IRQ_HASH		32	/* Can be adjusted later */
91 static struct hlist_head irq_lists[NR_IRQ_HASH];
92 static DEFINE_MUTEX(hash_mutex);	/* Used to walk the hash */
93 
94 /*
95  * This is the serial driver's interrupt routine.
96  *
97  * Arjan thinks the old way was overly complex, so it got simplified.
98  * Alan disagrees, saying that need the complexity to handle the weird
99  * nature of ISA shared interrupts.  (This is a special exception.)
100  *
101  * In order to handle ISA shared interrupts properly, we need to check
102  * that all ports have been serviced, and therefore the ISA interrupt
103  * line has been de-asserted.
104  *
105  * This means we need to loop through all ports. checking that they
106  * don't have an interrupt pending.
107  */
108 static irqreturn_t serial8250_interrupt(int irq, void *dev_id)
109 {
110 	struct irq_info *i = dev_id;
111 	struct list_head *l, *end = NULL;
112 	int pass_counter = 0, handled = 0;
113 
114 	pr_debug("%s(%d): start\n", __func__, irq);
115 
116 	spin_lock(&i->lock);
117 
118 	l = i->head;
119 	do {
120 		struct uart_8250_port *up;
121 		struct uart_port *port;
122 
123 		up = list_entry(l, struct uart_8250_port, list);
124 		port = &up->port;
125 
126 		if (port->handle_irq(port)) {
127 			handled = 1;
128 			end = NULL;
129 		} else if (end == NULL)
130 			end = l;
131 
132 		l = l->next;
133 
134 		if (l == i->head && pass_counter++ > PASS_LIMIT)
135 			break;
136 	} while (l != end);
137 
138 	spin_unlock(&i->lock);
139 
140 	pr_debug("%s(%d): end\n", __func__, irq);
141 
142 	return IRQ_RETVAL(handled);
143 }
144 
145 /*
146  * To support ISA shared interrupts, we need to have one interrupt
147  * handler that ensures that the IRQ line has been deasserted
148  * before returning.  Failing to do this will result in the IRQ
149  * line being stuck active, and, since ISA irqs are edge triggered,
150  * no more IRQs will be seen.
151  */
152 static void serial_do_unlink(struct irq_info *i, struct uart_8250_port *up)
153 {
154 	spin_lock_irq(&i->lock);
155 
156 	if (!list_empty(i->head)) {
157 		if (i->head == &up->list)
158 			i->head = i->head->next;
159 		list_del(&up->list);
160 	} else {
161 		BUG_ON(i->head != &up->list);
162 		i->head = NULL;
163 	}
164 	spin_unlock_irq(&i->lock);
165 	/* List empty so throw away the hash node */
166 	if (i->head == NULL) {
167 		hlist_del(&i->node);
168 		kfree(i);
169 	}
170 }
171 
172 static int serial_link_irq_chain(struct uart_8250_port *up)
173 {
174 	struct hlist_head *h;
175 	struct irq_info *i;
176 	int ret;
177 
178 	mutex_lock(&hash_mutex);
179 
180 	h = &irq_lists[up->port.irq % NR_IRQ_HASH];
181 
182 	hlist_for_each_entry(i, h, node)
183 		if (i->irq == up->port.irq)
184 			break;
185 
186 	if (i == NULL) {
187 		i = kzalloc(sizeof(struct irq_info), GFP_KERNEL);
188 		if (i == NULL) {
189 			mutex_unlock(&hash_mutex);
190 			return -ENOMEM;
191 		}
192 		spin_lock_init(&i->lock);
193 		i->irq = up->port.irq;
194 		hlist_add_head(&i->node, h);
195 	}
196 	mutex_unlock(&hash_mutex);
197 
198 	spin_lock_irq(&i->lock);
199 
200 	if (i->head) {
201 		list_add(&up->list, i->head);
202 		spin_unlock_irq(&i->lock);
203 
204 		ret = 0;
205 	} else {
206 		INIT_LIST_HEAD(&up->list);
207 		i->head = &up->list;
208 		spin_unlock_irq(&i->lock);
209 		ret = request_irq(up->port.irq, serial8250_interrupt,
210 				  up->port.irqflags, up->port.name, i);
211 		if (ret < 0)
212 			serial_do_unlink(i, up);
213 	}
214 
215 	return ret;
216 }
217 
218 static void serial_unlink_irq_chain(struct uart_8250_port *up)
219 {
220 	struct irq_info *i;
221 	struct hlist_head *h;
222 
223 	mutex_lock(&hash_mutex);
224 
225 	h = &irq_lists[up->port.irq % NR_IRQ_HASH];
226 
227 	hlist_for_each_entry(i, h, node)
228 		if (i->irq == up->port.irq)
229 			break;
230 
231 	BUG_ON(i == NULL);
232 	BUG_ON(i->head == NULL);
233 
234 	if (list_empty(i->head))
235 		free_irq(up->port.irq, i);
236 
237 	serial_do_unlink(i, up);
238 	mutex_unlock(&hash_mutex);
239 }
240 
241 /*
242  * This function is used to handle ports that do not have an
243  * interrupt.  This doesn't work very well for 16450's, but gives
244  * barely passable results for a 16550A.  (Although at the expense
245  * of much CPU overhead).
246  */
247 static void serial8250_timeout(struct timer_list *t)
248 {
249 	struct uart_8250_port *up = from_timer(up, t, timer);
250 
251 	up->port.handle_irq(&up->port);
252 	mod_timer(&up->timer, jiffies + uart_poll_timeout(&up->port));
253 }
254 
255 static void serial8250_backup_timeout(struct timer_list *t)
256 {
257 	struct uart_8250_port *up = from_timer(up, t, timer);
258 	unsigned int iir, ier = 0, lsr;
259 	unsigned long flags;
260 
261 	spin_lock_irqsave(&up->port.lock, flags);
262 
263 	/*
264 	 * Must disable interrupts or else we risk racing with the interrupt
265 	 * based handler.
266 	 */
267 	if (up->port.irq) {
268 		ier = serial_in(up, UART_IER);
269 		serial_out(up, UART_IER, 0);
270 	}
271 
272 	iir = serial_in(up, UART_IIR);
273 
274 	/*
275 	 * This should be a safe test for anyone who doesn't trust the
276 	 * IIR bits on their UART, but it's specifically designed for
277 	 * the "Diva" UART used on the management processor on many HP
278 	 * ia64 and parisc boxes.
279 	 */
280 	lsr = serial_lsr_in(up);
281 	if ((iir & UART_IIR_NO_INT) && (up->ier & UART_IER_THRI) &&
282 	    (!uart_circ_empty(&up->port.state->xmit) || up->port.x_char) &&
283 	    (lsr & UART_LSR_THRE)) {
284 		iir &= ~(UART_IIR_ID | UART_IIR_NO_INT);
285 		iir |= UART_IIR_THRI;
286 	}
287 
288 	if (!(iir & UART_IIR_NO_INT))
289 		serial8250_tx_chars(up);
290 
291 	if (up->port.irq)
292 		serial_out(up, UART_IER, ier);
293 
294 	spin_unlock_irqrestore(&up->port.lock, flags);
295 
296 	/* Standard timer interval plus 0.2s to keep the port running */
297 	mod_timer(&up->timer,
298 		jiffies + uart_poll_timeout(&up->port) + HZ / 5);
299 }
300 
301 static int univ8250_setup_irq(struct uart_8250_port *up)
302 {
303 	struct uart_port *port = &up->port;
304 	int retval = 0;
305 
306 	/*
307 	 * The above check will only give an accurate result the first time
308 	 * the port is opened so this value needs to be preserved.
309 	 */
310 	if (up->bugs & UART_BUG_THRE) {
311 		pr_debug("%s - using backup timer\n", port->name);
312 
313 		up->timer.function = serial8250_backup_timeout;
314 		mod_timer(&up->timer, jiffies +
315 			  uart_poll_timeout(port) + HZ / 5);
316 	}
317 
318 	/*
319 	 * If the "interrupt" for this port doesn't correspond with any
320 	 * hardware interrupt, we use a timer-based system.  The original
321 	 * driver used to do this with IRQ0.
322 	 */
323 	if (!port->irq)
324 		mod_timer(&up->timer, jiffies + uart_poll_timeout(port));
325 	else
326 		retval = serial_link_irq_chain(up);
327 
328 	return retval;
329 }
330 
331 static void univ8250_release_irq(struct uart_8250_port *up)
332 {
333 	struct uart_port *port = &up->port;
334 
335 	del_timer_sync(&up->timer);
336 	up->timer.function = serial8250_timeout;
337 	if (port->irq)
338 		serial_unlink_irq_chain(up);
339 }
340 
341 #ifdef CONFIG_SERIAL_8250_RSA
342 static int serial8250_request_rsa_resource(struct uart_8250_port *up)
343 {
344 	unsigned long start = UART_RSA_BASE << up->port.regshift;
345 	unsigned int size = 8 << up->port.regshift;
346 	struct uart_port *port = &up->port;
347 	int ret = -EINVAL;
348 
349 	switch (port->iotype) {
350 	case UPIO_HUB6:
351 	case UPIO_PORT:
352 		start += port->iobase;
353 		if (request_region(start, size, "serial-rsa"))
354 			ret = 0;
355 		else
356 			ret = -EBUSY;
357 		break;
358 	}
359 
360 	return ret;
361 }
362 
363 static void serial8250_release_rsa_resource(struct uart_8250_port *up)
364 {
365 	unsigned long offset = UART_RSA_BASE << up->port.regshift;
366 	unsigned int size = 8 << up->port.regshift;
367 	struct uart_port *port = &up->port;
368 
369 	switch (port->iotype) {
370 	case UPIO_HUB6:
371 	case UPIO_PORT:
372 		release_region(port->iobase + offset, size);
373 		break;
374 	}
375 }
376 #endif
377 
378 static const struct uart_ops *base_ops;
379 static struct uart_ops univ8250_port_ops;
380 
381 static const struct uart_8250_ops univ8250_driver_ops = {
382 	.setup_irq	= univ8250_setup_irq,
383 	.release_irq	= univ8250_release_irq,
384 };
385 
386 static struct uart_8250_port serial8250_ports[UART_NR];
387 
388 /**
389  * serial8250_get_port - retrieve struct uart_8250_port
390  * @line: serial line number
391  *
392  * This function retrieves struct uart_8250_port for the specific line.
393  * This struct *must* *not* be used to perform a 8250 or serial core operation
394  * which is not accessible otherwise. Its only purpose is to make the struct
395  * accessible to the runtime-pm callbacks for context suspend/restore.
396  * The lock assumption made here is none because runtime-pm suspend/resume
397  * callbacks should not be invoked if there is any operation performed on the
398  * port.
399  */
400 struct uart_8250_port *serial8250_get_port(int line)
401 {
402 	return &serial8250_ports[line];
403 }
404 EXPORT_SYMBOL_GPL(serial8250_get_port);
405 
406 static void (*serial8250_isa_config)(int port, struct uart_port *up,
407 	u32 *capabilities);
408 
409 void serial8250_set_isa_configurator(
410 	void (*v)(int port, struct uart_port *up, u32 *capabilities))
411 {
412 	serial8250_isa_config = v;
413 }
414 EXPORT_SYMBOL(serial8250_set_isa_configurator);
415 
416 #ifdef CONFIG_SERIAL_8250_RSA
417 
418 static void univ8250_config_port(struct uart_port *port, int flags)
419 {
420 	struct uart_8250_port *up = up_to_u8250p(port);
421 
422 	up->probe &= ~UART_PROBE_RSA;
423 	if (port->type == PORT_RSA) {
424 		if (serial8250_request_rsa_resource(up) == 0)
425 			up->probe |= UART_PROBE_RSA;
426 	} else if (flags & UART_CONFIG_TYPE) {
427 		int i;
428 
429 		for (i = 0; i < probe_rsa_count; i++) {
430 			if (probe_rsa[i] == up->port.iobase) {
431 				if (serial8250_request_rsa_resource(up) == 0)
432 					up->probe |= UART_PROBE_RSA;
433 				break;
434 			}
435 		}
436 	}
437 
438 	base_ops->config_port(port, flags);
439 
440 	if (port->type != PORT_RSA && up->probe & UART_PROBE_RSA)
441 		serial8250_release_rsa_resource(up);
442 }
443 
444 static int univ8250_request_port(struct uart_port *port)
445 {
446 	struct uart_8250_port *up = up_to_u8250p(port);
447 	int ret;
448 
449 	ret = base_ops->request_port(port);
450 	if (ret == 0 && port->type == PORT_RSA) {
451 		ret = serial8250_request_rsa_resource(up);
452 		if (ret < 0)
453 			base_ops->release_port(port);
454 	}
455 
456 	return ret;
457 }
458 
459 static void univ8250_release_port(struct uart_port *port)
460 {
461 	struct uart_8250_port *up = up_to_u8250p(port);
462 
463 	if (port->type == PORT_RSA)
464 		serial8250_release_rsa_resource(up);
465 	base_ops->release_port(port);
466 }
467 
468 static void univ8250_rsa_support(struct uart_ops *ops)
469 {
470 	ops->config_port  = univ8250_config_port;
471 	ops->request_port = univ8250_request_port;
472 	ops->release_port = univ8250_release_port;
473 }
474 
475 #else
476 #define univ8250_rsa_support(x)		do { } while (0)
477 #endif /* CONFIG_SERIAL_8250_RSA */
478 
479 static inline void serial8250_apply_quirks(struct uart_8250_port *up)
480 {
481 	up->port.quirks |= skip_txen_test ? UPQ_NO_TXEN_TEST : 0;
482 }
483 
484 static void __init serial8250_isa_init_ports(void)
485 {
486 	struct uart_8250_port *up;
487 	static int first = 1;
488 	int i, irqflag = 0;
489 
490 	if (!first)
491 		return;
492 	first = 0;
493 
494 	if (nr_uarts > UART_NR)
495 		nr_uarts = UART_NR;
496 
497 	for (i = 0; i < nr_uarts; i++) {
498 		struct uart_8250_port *up = &serial8250_ports[i];
499 		struct uart_port *port = &up->port;
500 
501 		port->line = i;
502 		serial8250_init_port(up);
503 		if (!base_ops)
504 			base_ops = port->ops;
505 		port->ops = &univ8250_port_ops;
506 
507 		timer_setup(&up->timer, serial8250_timeout, 0);
508 
509 		up->ops = &univ8250_driver_ops;
510 
511 		if (IS_ENABLED(CONFIG_ALPHA_JENSEN) ||
512 		    (IS_ENABLED(CONFIG_ALPHA_GENERIC) && alpha_jensen()))
513 			port->set_mctrl = alpha_jensen_set_mctrl;
514 
515 		serial8250_set_defaults(up);
516 	}
517 
518 	/* chain base port ops to support Remote Supervisor Adapter */
519 	univ8250_port_ops = *base_ops;
520 	univ8250_rsa_support(&univ8250_port_ops);
521 
522 	if (share_irqs)
523 		irqflag = IRQF_SHARED;
524 
525 	for (i = 0, up = serial8250_ports;
526 	     i < ARRAY_SIZE(old_serial_port) && i < nr_uarts;
527 	     i++, up++) {
528 		struct uart_port *port = &up->port;
529 
530 		port->iobase   = old_serial_port[i].port;
531 		port->irq      = irq_canonicalize(old_serial_port[i].irq);
532 		port->irqflags = 0;
533 		port->uartclk  = old_serial_port[i].baud_base * 16;
534 		port->flags    = old_serial_port[i].flags;
535 		port->hub6     = 0;
536 		port->membase  = old_serial_port[i].iomem_base;
537 		port->iotype   = old_serial_port[i].io_type;
538 		port->regshift = old_serial_port[i].iomem_reg_shift;
539 
540 		port->irqflags |= irqflag;
541 		if (serial8250_isa_config != NULL)
542 			serial8250_isa_config(i, &up->port, &up->capabilities);
543 	}
544 }
545 
546 static void __init
547 serial8250_register_ports(struct uart_driver *drv, struct device *dev)
548 {
549 	int i;
550 
551 	for (i = 0; i < nr_uarts; i++) {
552 		struct uart_8250_port *up = &serial8250_ports[i];
553 
554 		if (up->port.type == PORT_8250_CIR)
555 			continue;
556 
557 		if (up->port.dev)
558 			continue;
559 
560 		up->port.dev = dev;
561 
562 		if (uart_console_enabled(&up->port))
563 			pm_runtime_get_sync(up->port.dev);
564 
565 		serial8250_apply_quirks(up);
566 		uart_add_one_port(drv, &up->port);
567 	}
568 }
569 
570 #ifdef CONFIG_SERIAL_8250_CONSOLE
571 
572 static void univ8250_console_write(struct console *co, const char *s,
573 				   unsigned int count)
574 {
575 	struct uart_8250_port *up = &serial8250_ports[co->index];
576 
577 	serial8250_console_write(up, s, count);
578 }
579 
580 static int univ8250_console_setup(struct console *co, char *options)
581 {
582 	struct uart_port *port;
583 	int retval;
584 
585 	/*
586 	 * Check whether an invalid uart number has been specified, and
587 	 * if so, search for the first available port that does have
588 	 * console support.
589 	 */
590 	if (co->index >= nr_uarts)
591 		co->index = 0;
592 	port = &serial8250_ports[co->index].port;
593 	/* link port to console */
594 	port->cons = co;
595 
596 	retval = serial8250_console_setup(port, options, false);
597 	if (retval != 0)
598 		port->cons = NULL;
599 	return retval;
600 }
601 
602 static int univ8250_console_exit(struct console *co)
603 {
604 	struct uart_port *port;
605 
606 	port = &serial8250_ports[co->index].port;
607 	return serial8250_console_exit(port);
608 }
609 
610 /**
611  *	univ8250_console_match - non-standard console matching
612  *	@co:	  registering console
613  *	@name:	  name from console command line
614  *	@idx:	  index from console command line
615  *	@options: ptr to option string from console command line
616  *
617  *	Only attempts to match console command lines of the form:
618  *	    console=uart[8250],io|mmio|mmio16|mmio32,<addr>[,<options>]
619  *	    console=uart[8250],0x<addr>[,<options>]
620  *	This form is used to register an initial earlycon boot console and
621  *	replace it with the serial8250_console at 8250 driver init.
622  *
623  *	Performs console setup for a match (as required by interface)
624  *	If no <options> are specified, then assume the h/w is already setup.
625  *
626  *	Returns 0 if console matches; otherwise non-zero to use default matching
627  */
628 static int univ8250_console_match(struct console *co, char *name, int idx,
629 				  char *options)
630 {
631 	char match[] = "uart";	/* 8250-specific earlycon name */
632 	unsigned char iotype;
633 	resource_size_t addr;
634 	int i;
635 
636 	if (strncmp(name, match, 4) != 0)
637 		return -ENODEV;
638 
639 	if (uart_parse_earlycon(options, &iotype, &addr, &options))
640 		return -ENODEV;
641 
642 	/* try to match the port specified on the command line */
643 	for (i = 0; i < nr_uarts; i++) {
644 		struct uart_port *port = &serial8250_ports[i].port;
645 
646 		if (port->iotype != iotype)
647 			continue;
648 		if ((iotype == UPIO_MEM || iotype == UPIO_MEM16 ||
649 		     iotype == UPIO_MEM32 || iotype == UPIO_MEM32BE)
650 		    && (port->mapbase != addr))
651 			continue;
652 		if (iotype == UPIO_PORT && port->iobase != addr)
653 			continue;
654 
655 		co->index = i;
656 		port->cons = co;
657 		return serial8250_console_setup(port, options, true);
658 	}
659 
660 	return -ENODEV;
661 }
662 
663 static struct console univ8250_console = {
664 	.name		= "ttyS",
665 	.write		= univ8250_console_write,
666 	.device		= uart_console_device,
667 	.setup		= univ8250_console_setup,
668 	.exit		= univ8250_console_exit,
669 	.match		= univ8250_console_match,
670 	.flags		= CON_PRINTBUFFER | CON_ANYTIME,
671 	.index		= -1,
672 	.data		= &serial8250_reg,
673 };
674 
675 static int __init univ8250_console_init(void)
676 {
677 	if (nr_uarts == 0)
678 		return -ENODEV;
679 
680 	serial8250_isa_init_ports();
681 	register_console(&univ8250_console);
682 	return 0;
683 }
684 console_initcall(univ8250_console_init);
685 
686 #define SERIAL8250_CONSOLE	(&univ8250_console)
687 #else
688 #define SERIAL8250_CONSOLE	NULL
689 #endif
690 
691 static struct uart_driver serial8250_reg = {
692 	.owner			= THIS_MODULE,
693 	.driver_name		= "serial",
694 	.dev_name		= "ttyS",
695 	.major			= TTY_MAJOR,
696 	.minor			= 64,
697 	.cons			= SERIAL8250_CONSOLE,
698 };
699 
700 /*
701  * early_serial_setup - early registration for 8250 ports
702  *
703  * Setup an 8250 port structure prior to console initialisation.  Use
704  * after console initialisation will cause undefined behaviour.
705  */
706 int __init early_serial_setup(struct uart_port *port)
707 {
708 	struct uart_port *p;
709 
710 	if (port->line >= ARRAY_SIZE(serial8250_ports) || nr_uarts == 0)
711 		return -ENODEV;
712 
713 	serial8250_isa_init_ports();
714 	p = &serial8250_ports[port->line].port;
715 	p->iobase       = port->iobase;
716 	p->membase      = port->membase;
717 	p->irq          = port->irq;
718 	p->irqflags     = port->irqflags;
719 	p->uartclk      = port->uartclk;
720 	p->fifosize     = port->fifosize;
721 	p->regshift     = port->regshift;
722 	p->iotype       = port->iotype;
723 	p->flags        = port->flags;
724 	p->mapbase      = port->mapbase;
725 	p->mapsize      = port->mapsize;
726 	p->private_data = port->private_data;
727 	p->type		= port->type;
728 	p->line		= port->line;
729 
730 	serial8250_set_defaults(up_to_u8250p(p));
731 
732 	if (port->serial_in)
733 		p->serial_in = port->serial_in;
734 	if (port->serial_out)
735 		p->serial_out = port->serial_out;
736 	if (port->handle_irq)
737 		p->handle_irq = port->handle_irq;
738 
739 	return 0;
740 }
741 
742 /**
743  *	serial8250_suspend_port - suspend one serial port
744  *	@line:  serial line number
745  *
746  *	Suspend one serial port.
747  */
748 void serial8250_suspend_port(int line)
749 {
750 	struct uart_8250_port *up = &serial8250_ports[line];
751 	struct uart_port *port = &up->port;
752 
753 	if (!console_suspend_enabled && uart_console(port) &&
754 	    port->type != PORT_8250) {
755 		unsigned char canary = 0xa5;
756 
757 		serial_out(up, UART_SCR, canary);
758 		if (serial_in(up, UART_SCR) == canary)
759 			up->canary = canary;
760 	}
761 
762 	uart_suspend_port(&serial8250_reg, port);
763 }
764 EXPORT_SYMBOL(serial8250_suspend_port);
765 
766 /**
767  *	serial8250_resume_port - resume one serial port
768  *	@line:  serial line number
769  *
770  *	Resume one serial port.
771  */
772 void serial8250_resume_port(int line)
773 {
774 	struct uart_8250_port *up = &serial8250_ports[line];
775 	struct uart_port *port = &up->port;
776 
777 	up->canary = 0;
778 
779 	if (up->capabilities & UART_NATSEMI) {
780 		/* Ensure it's still in high speed mode */
781 		serial_port_out(port, UART_LCR, 0xE0);
782 
783 		ns16550a_goto_highspeed(up);
784 
785 		serial_port_out(port, UART_LCR, 0);
786 		port->uartclk = 921600*16;
787 	}
788 	uart_resume_port(&serial8250_reg, port);
789 }
790 EXPORT_SYMBOL(serial8250_resume_port);
791 
792 /*
793  * Register a set of serial devices attached to a platform device.  The
794  * list is terminated with a zero flags entry, which means we expect
795  * all entries to have at least UPF_BOOT_AUTOCONF set.
796  */
797 static int serial8250_probe(struct platform_device *dev)
798 {
799 	struct plat_serial8250_port *p = dev_get_platdata(&dev->dev);
800 	struct uart_8250_port uart;
801 	int ret, i, irqflag = 0;
802 
803 	memset(&uart, 0, sizeof(uart));
804 
805 	if (share_irqs)
806 		irqflag = IRQF_SHARED;
807 
808 	for (i = 0; p && p->flags != 0; p++, i++) {
809 		uart.port.iobase	= p->iobase;
810 		uart.port.membase	= p->membase;
811 		uart.port.irq		= p->irq;
812 		uart.port.irqflags	= p->irqflags;
813 		uart.port.uartclk	= p->uartclk;
814 		uart.port.regshift	= p->regshift;
815 		uart.port.iotype	= p->iotype;
816 		uart.port.flags		= p->flags;
817 		uart.port.mapbase	= p->mapbase;
818 		uart.port.hub6		= p->hub6;
819 		uart.port.has_sysrq	= p->has_sysrq;
820 		uart.port.private_data	= p->private_data;
821 		uart.port.type		= p->type;
822 		uart.port.serial_in	= p->serial_in;
823 		uart.port.serial_out	= p->serial_out;
824 		uart.port.handle_irq	= p->handle_irq;
825 		uart.port.handle_break	= p->handle_break;
826 		uart.port.set_termios	= p->set_termios;
827 		uart.port.set_ldisc	= p->set_ldisc;
828 		uart.port.get_mctrl	= p->get_mctrl;
829 		uart.port.pm		= p->pm;
830 		uart.port.dev		= &dev->dev;
831 		uart.port.irqflags	|= irqflag;
832 		ret = serial8250_register_8250_port(&uart);
833 		if (ret < 0) {
834 			dev_err(&dev->dev, "unable to register port at index %d "
835 				"(IO%lx MEM%llx IRQ%d): %d\n", i,
836 				p->iobase, (unsigned long long)p->mapbase,
837 				p->irq, ret);
838 		}
839 	}
840 	return 0;
841 }
842 
843 /*
844  * Remove serial ports registered against a platform device.
845  */
846 static int serial8250_remove(struct platform_device *dev)
847 {
848 	int i;
849 
850 	for (i = 0; i < nr_uarts; i++) {
851 		struct uart_8250_port *up = &serial8250_ports[i];
852 
853 		if (up->port.dev == &dev->dev)
854 			serial8250_unregister_port(i);
855 	}
856 	return 0;
857 }
858 
859 static int serial8250_suspend(struct platform_device *dev, pm_message_t state)
860 {
861 	int i;
862 
863 	for (i = 0; i < UART_NR; i++) {
864 		struct uart_8250_port *up = &serial8250_ports[i];
865 
866 		if (up->port.type != PORT_UNKNOWN && up->port.dev == &dev->dev)
867 			uart_suspend_port(&serial8250_reg, &up->port);
868 	}
869 
870 	return 0;
871 }
872 
873 static int serial8250_resume(struct platform_device *dev)
874 {
875 	int i;
876 
877 	for (i = 0; i < UART_NR; i++) {
878 		struct uart_8250_port *up = &serial8250_ports[i];
879 
880 		if (up->port.type != PORT_UNKNOWN && up->port.dev == &dev->dev)
881 			serial8250_resume_port(i);
882 	}
883 
884 	return 0;
885 }
886 
887 static struct platform_driver serial8250_isa_driver = {
888 	.probe		= serial8250_probe,
889 	.remove		= serial8250_remove,
890 	.suspend	= serial8250_suspend,
891 	.resume		= serial8250_resume,
892 	.driver		= {
893 		.name	= "serial8250",
894 	},
895 };
896 
897 /*
898  * This "device" covers _all_ ISA 8250-compatible serial devices listed
899  * in the table in include/asm/serial.h
900  */
901 static struct platform_device *serial8250_isa_devs;
902 
903 /*
904  * serial8250_register_8250_port and serial8250_unregister_port allows for
905  * 16x50 serial ports to be configured at run-time, to support PCMCIA
906  * modems and PCI multiport cards.
907  */
908 static DEFINE_MUTEX(serial_mutex);
909 
910 static struct uart_8250_port *serial8250_find_match_or_unused(const struct uart_port *port)
911 {
912 	int i;
913 
914 	/*
915 	 * First, find a port entry which matches.
916 	 */
917 	for (i = 0; i < nr_uarts; i++)
918 		if (uart_match_port(&serial8250_ports[i].port, port))
919 			return &serial8250_ports[i];
920 
921 	/* try line number first if still available */
922 	i = port->line;
923 	if (i < nr_uarts && serial8250_ports[i].port.type == PORT_UNKNOWN &&
924 			serial8250_ports[i].port.iobase == 0)
925 		return &serial8250_ports[i];
926 	/*
927 	 * We didn't find a matching entry, so look for the first
928 	 * free entry.  We look for one which hasn't been previously
929 	 * used (indicated by zero iobase).
930 	 */
931 	for (i = 0; i < nr_uarts; i++)
932 		if (serial8250_ports[i].port.type == PORT_UNKNOWN &&
933 		    serial8250_ports[i].port.iobase == 0)
934 			return &serial8250_ports[i];
935 
936 	/*
937 	 * That also failed.  Last resort is to find any entry which
938 	 * doesn't have a real port associated with it.
939 	 */
940 	for (i = 0; i < nr_uarts; i++)
941 		if (serial8250_ports[i].port.type == PORT_UNKNOWN)
942 			return &serial8250_ports[i];
943 
944 	return NULL;
945 }
946 
947 static void serial_8250_overrun_backoff_work(struct work_struct *work)
948 {
949 	struct uart_8250_port *up =
950 	    container_of(to_delayed_work(work), struct uart_8250_port,
951 			 overrun_backoff);
952 	struct uart_port *port = &up->port;
953 	unsigned long flags;
954 
955 	spin_lock_irqsave(&port->lock, flags);
956 	up->ier |= UART_IER_RLSI | UART_IER_RDI;
957 	up->port.read_status_mask |= UART_LSR_DR;
958 	serial_out(up, UART_IER, up->ier);
959 	spin_unlock_irqrestore(&port->lock, flags);
960 }
961 
962 /**
963  *	serial8250_register_8250_port - register a serial port
964  *	@up: serial port template
965  *
966  *	Configure the serial port specified by the request. If the
967  *	port exists and is in use, it is hung up and unregistered
968  *	first.
969  *
970  *	The port is then probed and if necessary the IRQ is autodetected
971  *	If this fails an error is returned.
972  *
973  *	On success the port is ready to use and the line number is returned.
974  */
975 int serial8250_register_8250_port(const struct uart_8250_port *up)
976 {
977 	struct uart_8250_port *uart;
978 	int ret = -ENOSPC;
979 
980 	if (up->port.uartclk == 0)
981 		return -EINVAL;
982 
983 	mutex_lock(&serial_mutex);
984 
985 	uart = serial8250_find_match_or_unused(&up->port);
986 	if (uart && uart->port.type != PORT_8250_CIR) {
987 		struct mctrl_gpios *gpios;
988 
989 		if (uart->port.dev)
990 			uart_remove_one_port(&serial8250_reg, &uart->port);
991 
992 		uart->port.iobase       = up->port.iobase;
993 		uart->port.membase      = up->port.membase;
994 		uart->port.irq          = up->port.irq;
995 		uart->port.irqflags     = up->port.irqflags;
996 		uart->port.uartclk      = up->port.uartclk;
997 		uart->port.fifosize     = up->port.fifosize;
998 		uart->port.regshift     = up->port.regshift;
999 		uart->port.iotype       = up->port.iotype;
1000 		uart->port.flags        = up->port.flags | UPF_BOOT_AUTOCONF;
1001 		uart->bugs		= up->bugs;
1002 		uart->port.mapbase      = up->port.mapbase;
1003 		uart->port.mapsize      = up->port.mapsize;
1004 		uart->port.private_data = up->port.private_data;
1005 		uart->tx_loadsz		= up->tx_loadsz;
1006 		uart->capabilities	= up->capabilities;
1007 		uart->port.throttle	= up->port.throttle;
1008 		uart->port.unthrottle	= up->port.unthrottle;
1009 		uart->port.rs485_config	= up->port.rs485_config;
1010 		uart->port.rs485_supported = up->port.rs485_supported;
1011 		uart->port.rs485	= up->port.rs485;
1012 		uart->rs485_start_tx	= up->rs485_start_tx;
1013 		uart->rs485_stop_tx	= up->rs485_stop_tx;
1014 		uart->lsr_save_mask	= up->lsr_save_mask;
1015 		uart->dma		= up->dma;
1016 
1017 		/* Take tx_loadsz from fifosize if it wasn't set separately */
1018 		if (uart->port.fifosize && !uart->tx_loadsz)
1019 			uart->tx_loadsz = uart->port.fifosize;
1020 
1021 		if (up->port.dev) {
1022 			uart->port.dev = up->port.dev;
1023 			ret = uart_get_rs485_mode(&uart->port);
1024 			if (ret)
1025 				goto err;
1026 		}
1027 
1028 		if (up->port.flags & UPF_FIXED_TYPE)
1029 			uart->port.type = up->port.type;
1030 
1031 		/*
1032 		 * Only call mctrl_gpio_init(), if the device has no ACPI
1033 		 * companion device
1034 		 */
1035 		if (!has_acpi_companion(uart->port.dev)) {
1036 			gpios = mctrl_gpio_init(&uart->port, 0);
1037 			if (IS_ERR(gpios)) {
1038 				ret = PTR_ERR(gpios);
1039 				goto err;
1040 			} else {
1041 				uart->gpios = gpios;
1042 			}
1043 		}
1044 
1045 		serial8250_set_defaults(uart);
1046 
1047 		/* Possibly override default I/O functions.  */
1048 		if (up->port.serial_in)
1049 			uart->port.serial_in = up->port.serial_in;
1050 		if (up->port.serial_out)
1051 			uart->port.serial_out = up->port.serial_out;
1052 		if (up->port.handle_irq)
1053 			uart->port.handle_irq = up->port.handle_irq;
1054 		/*  Possibly override set_termios call */
1055 		if (up->port.set_termios)
1056 			uart->port.set_termios = up->port.set_termios;
1057 		if (up->port.set_ldisc)
1058 			uart->port.set_ldisc = up->port.set_ldisc;
1059 		if (up->port.get_mctrl)
1060 			uart->port.get_mctrl = up->port.get_mctrl;
1061 		if (up->port.set_mctrl)
1062 			uart->port.set_mctrl = up->port.set_mctrl;
1063 		if (up->port.get_divisor)
1064 			uart->port.get_divisor = up->port.get_divisor;
1065 		if (up->port.set_divisor)
1066 			uart->port.set_divisor = up->port.set_divisor;
1067 		if (up->port.startup)
1068 			uart->port.startup = up->port.startup;
1069 		if (up->port.shutdown)
1070 			uart->port.shutdown = up->port.shutdown;
1071 		if (up->port.pm)
1072 			uart->port.pm = up->port.pm;
1073 		if (up->port.handle_break)
1074 			uart->port.handle_break = up->port.handle_break;
1075 		if (up->dl_read)
1076 			uart->dl_read = up->dl_read;
1077 		if (up->dl_write)
1078 			uart->dl_write = up->dl_write;
1079 
1080 		if (uart->port.type != PORT_8250_CIR) {
1081 			if (serial8250_isa_config != NULL)
1082 				serial8250_isa_config(0, &uart->port,
1083 						&uart->capabilities);
1084 
1085 			serial8250_apply_quirks(uart);
1086 			ret = uart_add_one_port(&serial8250_reg,
1087 						&uart->port);
1088 			if (ret)
1089 				goto err;
1090 
1091 			ret = uart->port.line;
1092 		} else {
1093 			dev_info(uart->port.dev,
1094 				"skipping CIR port at 0x%lx / 0x%llx, IRQ %d\n",
1095 				uart->port.iobase,
1096 				(unsigned long long)uart->port.mapbase,
1097 				uart->port.irq);
1098 
1099 			ret = 0;
1100 		}
1101 
1102 		if (!uart->lsr_save_mask)
1103 			uart->lsr_save_mask = LSR_SAVE_FLAGS;	/* Use default LSR mask */
1104 
1105 		/* Initialise interrupt backoff work if required */
1106 		if (up->overrun_backoff_time_ms > 0) {
1107 			uart->overrun_backoff_time_ms =
1108 				up->overrun_backoff_time_ms;
1109 			INIT_DELAYED_WORK(&uart->overrun_backoff,
1110 					serial_8250_overrun_backoff_work);
1111 		} else {
1112 			uart->overrun_backoff_time_ms = 0;
1113 		}
1114 	}
1115 
1116 	mutex_unlock(&serial_mutex);
1117 
1118 	return ret;
1119 
1120 err:
1121 	uart->port.dev = NULL;
1122 	mutex_unlock(&serial_mutex);
1123 	return ret;
1124 }
1125 EXPORT_SYMBOL(serial8250_register_8250_port);
1126 
1127 /**
1128  *	serial8250_unregister_port - remove a 16x50 serial port at runtime
1129  *	@line: serial line number
1130  *
1131  *	Remove one serial port.  This may not be called from interrupt
1132  *	context.  We hand the port back to the our control.
1133  */
1134 void serial8250_unregister_port(int line)
1135 {
1136 	struct uart_8250_port *uart = &serial8250_ports[line];
1137 
1138 	mutex_lock(&serial_mutex);
1139 
1140 	if (uart->em485) {
1141 		unsigned long flags;
1142 
1143 		spin_lock_irqsave(&uart->port.lock, flags);
1144 		serial8250_em485_destroy(uart);
1145 		spin_unlock_irqrestore(&uart->port.lock, flags);
1146 	}
1147 
1148 	uart_remove_one_port(&serial8250_reg, &uart->port);
1149 	if (serial8250_isa_devs) {
1150 		uart->port.flags &= ~UPF_BOOT_AUTOCONF;
1151 		uart->port.type = PORT_UNKNOWN;
1152 		uart->port.dev = &serial8250_isa_devs->dev;
1153 		uart->capabilities = 0;
1154 		serial8250_apply_quirks(uart);
1155 		uart_add_one_port(&serial8250_reg, &uart->port);
1156 	} else {
1157 		uart->port.dev = NULL;
1158 	}
1159 	mutex_unlock(&serial_mutex);
1160 }
1161 EXPORT_SYMBOL(serial8250_unregister_port);
1162 
1163 static int __init serial8250_init(void)
1164 {
1165 	int ret;
1166 
1167 	if (nr_uarts == 0)
1168 		return -ENODEV;
1169 
1170 	serial8250_isa_init_ports();
1171 
1172 	pr_info("Serial: 8250/16550 driver, %d ports, IRQ sharing %sabled\n",
1173 		nr_uarts, share_irqs ? "en" : "dis");
1174 
1175 #ifdef CONFIG_SPARC
1176 	ret = sunserial_register_minors(&serial8250_reg, UART_NR);
1177 #else
1178 	serial8250_reg.nr = UART_NR;
1179 	ret = uart_register_driver(&serial8250_reg);
1180 #endif
1181 	if (ret)
1182 		goto out;
1183 
1184 	ret = serial8250_pnp_init();
1185 	if (ret)
1186 		goto unreg_uart_drv;
1187 
1188 	serial8250_isa_devs = platform_device_alloc("serial8250",
1189 						    PLAT8250_DEV_LEGACY);
1190 	if (!serial8250_isa_devs) {
1191 		ret = -ENOMEM;
1192 		goto unreg_pnp;
1193 	}
1194 
1195 	ret = platform_device_add(serial8250_isa_devs);
1196 	if (ret)
1197 		goto put_dev;
1198 
1199 	serial8250_register_ports(&serial8250_reg, &serial8250_isa_devs->dev);
1200 
1201 	ret = platform_driver_register(&serial8250_isa_driver);
1202 	if (ret == 0)
1203 		goto out;
1204 
1205 	platform_device_del(serial8250_isa_devs);
1206 put_dev:
1207 	platform_device_put(serial8250_isa_devs);
1208 unreg_pnp:
1209 	serial8250_pnp_exit();
1210 unreg_uart_drv:
1211 #ifdef CONFIG_SPARC
1212 	sunserial_unregister_minors(&serial8250_reg, UART_NR);
1213 #else
1214 	uart_unregister_driver(&serial8250_reg);
1215 #endif
1216 out:
1217 	return ret;
1218 }
1219 
1220 static void __exit serial8250_exit(void)
1221 {
1222 	struct platform_device *isa_dev = serial8250_isa_devs;
1223 
1224 	/*
1225 	 * This tells serial8250_unregister_port() not to re-register
1226 	 * the ports (thereby making serial8250_isa_driver permanently
1227 	 * in use.)
1228 	 */
1229 	serial8250_isa_devs = NULL;
1230 
1231 	platform_driver_unregister(&serial8250_isa_driver);
1232 	platform_device_unregister(isa_dev);
1233 
1234 	serial8250_pnp_exit();
1235 
1236 #ifdef CONFIG_SPARC
1237 	sunserial_unregister_minors(&serial8250_reg, UART_NR);
1238 #else
1239 	uart_unregister_driver(&serial8250_reg);
1240 #endif
1241 }
1242 
1243 module_init(serial8250_init);
1244 module_exit(serial8250_exit);
1245 
1246 MODULE_LICENSE("GPL");
1247 MODULE_DESCRIPTION("Generic 8250/16x50 serial driver");
1248 
1249 module_param_hw(share_irqs, uint, other, 0644);
1250 MODULE_PARM_DESC(share_irqs, "Share IRQs with other non-8250/16x50 devices (unsafe)");
1251 
1252 module_param(nr_uarts, uint, 0644);
1253 MODULE_PARM_DESC(nr_uarts, "Maximum number of UARTs supported. (1-" __MODULE_STRING(CONFIG_SERIAL_8250_NR_UARTS) ")");
1254 
1255 module_param(skip_txen_test, uint, 0644);
1256 MODULE_PARM_DESC(skip_txen_test, "Skip checking for the TXEN bug at init time");
1257 
1258 #ifdef CONFIG_SERIAL_8250_RSA
1259 module_param_hw_array(probe_rsa, ulong, ioport, &probe_rsa_count, 0444);
1260 MODULE_PARM_DESC(probe_rsa, "Probe I/O ports for RSA");
1261 #endif
1262 MODULE_ALIAS_CHARDEV_MAJOR(TTY_MAJOR);
1263 
1264 #ifdef CONFIG_SERIAL_8250_DEPRECATED_OPTIONS
1265 #ifndef MODULE
1266 /* This module was renamed to 8250_core in 3.7.  Keep the old "8250" name
1267  * working as well for the module options so we don't break people.  We
1268  * need to keep the names identical and the convenient macros will happily
1269  * refuse to let us do that by failing the build with redefinition errors
1270  * of global variables.  So we stick them inside a dummy function to avoid
1271  * those conflicts.  The options still get parsed, and the redefined
1272  * MODULE_PARAM_PREFIX lets us keep the "8250." syntax alive.
1273  *
1274  * This is hacky.  I'm sorry.
1275  */
1276 static void __used s8250_options(void)
1277 {
1278 #undef MODULE_PARAM_PREFIX
1279 #define MODULE_PARAM_PREFIX "8250_core."
1280 
1281 	module_param_cb(share_irqs, &param_ops_uint, &share_irqs, 0644);
1282 	module_param_cb(nr_uarts, &param_ops_uint, &nr_uarts, 0644);
1283 	module_param_cb(skip_txen_test, &param_ops_uint, &skip_txen_test, 0644);
1284 #ifdef CONFIG_SERIAL_8250_RSA
1285 	__module_param_call(MODULE_PARAM_PREFIX, probe_rsa,
1286 		&param_array_ops, .arr = &__param_arr_probe_rsa,
1287 		0444, -1, 0);
1288 #endif
1289 }
1290 #else
1291 MODULE_ALIAS("8250_core");
1292 #endif
1293 #endif
1294