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/string_helpers.h>
36 #include <linux/uaccess.h>
37 #include <linux/io.h>
38 #ifdef CONFIG_SPARC
39 #include <linux/sunserialcore.h>
40 #endif
41 
42 #include <asm/irq.h>
43 
44 #include "8250.h"
45 
46 /*
47  * Configuration:
48  *   share_irqs - whether we pass IRQF_SHARED to request_irq().  This option
49  *                is unsafe when used on edge-triggered interrupts.
50  */
51 static unsigned int share_irqs = SERIAL8250_SHARE_IRQS;
52 
53 static unsigned int nr_uarts = CONFIG_SERIAL_8250_RUNTIME_UARTS;
54 
55 static struct uart_driver serial8250_reg;
56 
57 static unsigned int skip_txen_test; /* force skip of txen test at init time */
58 
59 #define PASS_LIMIT	512
60 
61 #include <asm/serial.h>
62 /*
63  * SERIAL_PORT_DFNS tells us about built-in ports that have no
64  * standard enumeration mechanism.   Platforms that can find all
65  * serial ports via mechanisms like ACPI or PCI need not supply it.
66  */
67 #ifndef SERIAL_PORT_DFNS
68 #define SERIAL_PORT_DFNS
69 #endif
70 
71 static const struct old_serial_port old_serial_port[] = {
72 	SERIAL_PORT_DFNS /* defined in asm/serial.h */
73 };
74 
75 #define UART_NR	CONFIG_SERIAL_8250_NR_UARTS
76 
77 #ifdef CONFIG_SERIAL_8250_RSA
78 
79 #define PORT_RSA_MAX 4
80 static unsigned long probe_rsa[PORT_RSA_MAX];
81 static unsigned int probe_rsa_count;
82 #endif /* CONFIG_SERIAL_8250_RSA  */
83 
84 struct irq_info {
85 	struct			hlist_node node;
86 	int			irq;
87 	spinlock_t		lock;	/* Protects list not the hash */
88 	struct list_head	*head;
89 };
90 
91 #define NR_IRQ_HASH		32	/* Can be adjusted later */
92 static struct hlist_head irq_lists[NR_IRQ_HASH];
93 static DEFINE_MUTEX(hash_mutex);	/* Used to walk the hash */
94 
95 /*
96  * This is the serial driver's interrupt routine.
97  *
98  * Arjan thinks the old way was overly complex, so it got simplified.
99  * Alan disagrees, saying that need the complexity to handle the weird
100  * nature of ISA shared interrupts.  (This is a special exception.)
101  *
102  * In order to handle ISA shared interrupts properly, we need to check
103  * that all ports have been serviced, and therefore the ISA interrupt
104  * line has been de-asserted.
105  *
106  * This means we need to loop through all ports. checking that they
107  * don't have an interrupt pending.
108  */
109 static irqreturn_t serial8250_interrupt(int irq, void *dev_id)
110 {
111 	struct irq_info *i = dev_id;
112 	struct list_head *l, *end = NULL;
113 	int pass_counter = 0, handled = 0;
114 
115 	pr_debug("%s(%d): start\n", __func__, irq);
116 
117 	spin_lock(&i->lock);
118 
119 	l = i->head;
120 	do {
121 		struct uart_8250_port *up;
122 		struct uart_port *port;
123 
124 		up = list_entry(l, struct uart_8250_port, list);
125 		port = &up->port;
126 
127 		if (port->handle_irq(port)) {
128 			handled = 1;
129 			end = NULL;
130 		} else if (end == NULL)
131 			end = l;
132 
133 		l = l->next;
134 
135 		if (l == i->head && pass_counter++ > PASS_LIMIT)
136 			break;
137 	} while (l != end);
138 
139 	spin_unlock(&i->lock);
140 
141 	pr_debug("%s(%d): end\n", __func__, irq);
142 
143 	return IRQ_RETVAL(handled);
144 }
145 
146 /*
147  * To support ISA shared interrupts, we need to have one interrupt
148  * handler that ensures that the IRQ line has been deasserted
149  * before returning.  Failing to do this will result in the IRQ
150  * line being stuck active, and, since ISA irqs are edge triggered,
151  * no more IRQs will be seen.
152  */
153 static void serial_do_unlink(struct irq_info *i, struct uart_8250_port *up)
154 {
155 	spin_lock_irq(&i->lock);
156 
157 	if (!list_empty(i->head)) {
158 		if (i->head == &up->list)
159 			i->head = i->head->next;
160 		list_del(&up->list);
161 	} else {
162 		BUG_ON(i->head != &up->list);
163 		i->head = NULL;
164 	}
165 	spin_unlock_irq(&i->lock);
166 	/* List empty so throw away the hash node */
167 	if (i->head == NULL) {
168 		hlist_del(&i->node);
169 		kfree(i);
170 	}
171 }
172 
173 static int serial_link_irq_chain(struct uart_8250_port *up)
174 {
175 	struct hlist_head *h;
176 	struct irq_info *i;
177 	int ret;
178 
179 	mutex_lock(&hash_mutex);
180 
181 	h = &irq_lists[up->port.irq % NR_IRQ_HASH];
182 
183 	hlist_for_each_entry(i, h, node)
184 		if (i->irq == up->port.irq)
185 			break;
186 
187 	if (i == NULL) {
188 		i = kzalloc(sizeof(struct irq_info), GFP_KERNEL);
189 		if (i == NULL) {
190 			mutex_unlock(&hash_mutex);
191 			return -ENOMEM;
192 		}
193 		spin_lock_init(&i->lock);
194 		i->irq = up->port.irq;
195 		hlist_add_head(&i->node, h);
196 	}
197 	mutex_unlock(&hash_mutex);
198 
199 	spin_lock_irq(&i->lock);
200 
201 	if (i->head) {
202 		list_add(&up->list, i->head);
203 		spin_unlock_irq(&i->lock);
204 
205 		ret = 0;
206 	} else {
207 		INIT_LIST_HEAD(&up->list);
208 		i->head = &up->list;
209 		spin_unlock_irq(&i->lock);
210 		ret = request_irq(up->port.irq, serial8250_interrupt,
211 				  up->port.irqflags, up->port.name, i);
212 		if (ret < 0)
213 			serial_do_unlink(i, up);
214 	}
215 
216 	return ret;
217 }
218 
219 static void serial_unlink_irq_chain(struct uart_8250_port *up)
220 {
221 	struct irq_info *i;
222 	struct hlist_head *h;
223 
224 	mutex_lock(&hash_mutex);
225 
226 	h = &irq_lists[up->port.irq % NR_IRQ_HASH];
227 
228 	hlist_for_each_entry(i, h, node)
229 		if (i->irq == up->port.irq)
230 			break;
231 
232 	BUG_ON(i == NULL);
233 	BUG_ON(i->head == NULL);
234 
235 	if (list_empty(i->head))
236 		free_irq(up->port.irq, i);
237 
238 	serial_do_unlink(i, up);
239 	mutex_unlock(&hash_mutex);
240 }
241 
242 /*
243  * This function is used to handle ports that do not have an
244  * interrupt.  This doesn't work very well for 16450's, but gives
245  * barely passable results for a 16550A.  (Although at the expense
246  * of much CPU overhead).
247  */
248 static void serial8250_timeout(struct timer_list *t)
249 {
250 	struct uart_8250_port *up = from_timer(up, t, timer);
251 
252 	up->port.handle_irq(&up->port);
253 	mod_timer(&up->timer, jiffies + uart_poll_timeout(&up->port));
254 }
255 
256 static void serial8250_backup_timeout(struct timer_list *t)
257 {
258 	struct uart_8250_port *up = from_timer(up, t, timer);
259 	unsigned int iir, ier = 0, lsr;
260 	unsigned long flags;
261 
262 	spin_lock_irqsave(&up->port.lock, flags);
263 
264 	/*
265 	 * Must disable interrupts or else we risk racing with the interrupt
266 	 * based handler.
267 	 */
268 	if (up->port.irq) {
269 		ier = serial_in(up, UART_IER);
270 		serial_out(up, UART_IER, 0);
271 	}
272 
273 	iir = serial_in(up, UART_IIR);
274 
275 	/*
276 	 * This should be a safe test for anyone who doesn't trust the
277 	 * IIR bits on their UART, but it's specifically designed for
278 	 * the "Diva" UART used on the management processor on many HP
279 	 * ia64 and parisc boxes.
280 	 */
281 	lsr = serial_lsr_in(up);
282 	if ((iir & UART_IIR_NO_INT) && (up->ier & UART_IER_THRI) &&
283 	    (!uart_circ_empty(&up->port.state->xmit) || up->port.x_char) &&
284 	    (lsr & UART_LSR_THRE)) {
285 		iir &= ~(UART_IIR_ID | UART_IIR_NO_INT);
286 		iir |= UART_IIR_THRI;
287 	}
288 
289 	if (!(iir & UART_IIR_NO_INT))
290 		serial8250_tx_chars(up);
291 
292 	if (up->port.irq)
293 		serial_out(up, UART_IER, ier);
294 
295 	spin_unlock_irqrestore(&up->port.lock, flags);
296 
297 	/* Standard timer interval plus 0.2s to keep the port running */
298 	mod_timer(&up->timer,
299 		jiffies + uart_poll_timeout(&up->port) + HZ / 5);
300 }
301 
302 static void univ8250_setup_timer(struct uart_8250_port *up)
303 {
304 	struct uart_port *port = &up->port;
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 }
326 
327 static int univ8250_setup_irq(struct uart_8250_port *up)
328 {
329 	struct uart_port *port = &up->port;
330 
331 	if (port->irq)
332 		return serial_link_irq_chain(up);
333 
334 	return 0;
335 }
336 
337 static void univ8250_release_irq(struct uart_8250_port *up)
338 {
339 	struct uart_port *port = &up->port;
340 
341 	del_timer_sync(&up->timer);
342 	up->timer.function = serial8250_timeout;
343 	if (port->irq)
344 		serial_unlink_irq_chain(up);
345 }
346 
347 #ifdef CONFIG_SERIAL_8250_RSA
348 static int serial8250_request_rsa_resource(struct uart_8250_port *up)
349 {
350 	unsigned long start = UART_RSA_BASE << up->port.regshift;
351 	unsigned int size = 8 << up->port.regshift;
352 	struct uart_port *port = &up->port;
353 	int ret = -EINVAL;
354 
355 	switch (port->iotype) {
356 	case UPIO_HUB6:
357 	case UPIO_PORT:
358 		start += port->iobase;
359 		if (request_region(start, size, "serial-rsa"))
360 			ret = 0;
361 		else
362 			ret = -EBUSY;
363 		break;
364 	}
365 
366 	return ret;
367 }
368 
369 static void serial8250_release_rsa_resource(struct uart_8250_port *up)
370 {
371 	unsigned long offset = UART_RSA_BASE << up->port.regshift;
372 	unsigned int size = 8 << up->port.regshift;
373 	struct uart_port *port = &up->port;
374 
375 	switch (port->iotype) {
376 	case UPIO_HUB6:
377 	case UPIO_PORT:
378 		release_region(port->iobase + offset, size);
379 		break;
380 	}
381 }
382 #endif
383 
384 static const struct uart_ops *base_ops;
385 static struct uart_ops univ8250_port_ops;
386 
387 static const struct uart_8250_ops univ8250_driver_ops = {
388 	.setup_irq	= univ8250_setup_irq,
389 	.release_irq	= univ8250_release_irq,
390 	.setup_timer	= univ8250_setup_timer,
391 };
392 
393 static struct uart_8250_port serial8250_ports[UART_NR];
394 
395 /**
396  * serial8250_get_port - retrieve struct uart_8250_port
397  * @line: serial line number
398  *
399  * This function retrieves struct uart_8250_port for the specific line.
400  * This struct *must* *not* be used to perform a 8250 or serial core operation
401  * which is not accessible otherwise. Its only purpose is to make the struct
402  * accessible to the runtime-pm callbacks for context suspend/restore.
403  * The lock assumption made here is none because runtime-pm suspend/resume
404  * callbacks should not be invoked if there is any operation performed on the
405  * port.
406  */
407 struct uart_8250_port *serial8250_get_port(int line)
408 {
409 	return &serial8250_ports[line];
410 }
411 EXPORT_SYMBOL_GPL(serial8250_get_port);
412 
413 static void (*serial8250_isa_config)(int port, struct uart_port *up,
414 	u32 *capabilities);
415 
416 void serial8250_set_isa_configurator(
417 	void (*v)(int port, struct uart_port *up, u32 *capabilities))
418 {
419 	serial8250_isa_config = v;
420 }
421 EXPORT_SYMBOL(serial8250_set_isa_configurator);
422 
423 #ifdef CONFIG_SERIAL_8250_RSA
424 
425 static void univ8250_config_port(struct uart_port *port, int flags)
426 {
427 	struct uart_8250_port *up = up_to_u8250p(port);
428 
429 	up->probe &= ~UART_PROBE_RSA;
430 	if (port->type == PORT_RSA) {
431 		if (serial8250_request_rsa_resource(up) == 0)
432 			up->probe |= UART_PROBE_RSA;
433 	} else if (flags & UART_CONFIG_TYPE) {
434 		int i;
435 
436 		for (i = 0; i < probe_rsa_count; i++) {
437 			if (probe_rsa[i] == up->port.iobase) {
438 				if (serial8250_request_rsa_resource(up) == 0)
439 					up->probe |= UART_PROBE_RSA;
440 				break;
441 			}
442 		}
443 	}
444 
445 	base_ops->config_port(port, flags);
446 
447 	if (port->type != PORT_RSA && up->probe & UART_PROBE_RSA)
448 		serial8250_release_rsa_resource(up);
449 }
450 
451 static int univ8250_request_port(struct uart_port *port)
452 {
453 	struct uart_8250_port *up = up_to_u8250p(port);
454 	int ret;
455 
456 	ret = base_ops->request_port(port);
457 	if (ret == 0 && port->type == PORT_RSA) {
458 		ret = serial8250_request_rsa_resource(up);
459 		if (ret < 0)
460 			base_ops->release_port(port);
461 	}
462 
463 	return ret;
464 }
465 
466 static void univ8250_release_port(struct uart_port *port)
467 {
468 	struct uart_8250_port *up = up_to_u8250p(port);
469 
470 	if (port->type == PORT_RSA)
471 		serial8250_release_rsa_resource(up);
472 	base_ops->release_port(port);
473 }
474 
475 static void univ8250_rsa_support(struct uart_ops *ops)
476 {
477 	ops->config_port  = univ8250_config_port;
478 	ops->request_port = univ8250_request_port;
479 	ops->release_port = univ8250_release_port;
480 }
481 
482 #else
483 #define univ8250_rsa_support(x)		do { } while (0)
484 #endif /* CONFIG_SERIAL_8250_RSA */
485 
486 static inline void serial8250_apply_quirks(struct uart_8250_port *up)
487 {
488 	up->port.quirks |= skip_txen_test ? UPQ_NO_TXEN_TEST : 0;
489 }
490 
491 static void __init serial8250_isa_init_ports(void)
492 {
493 	struct uart_8250_port *up;
494 	static int first = 1;
495 	int i, irqflag = 0;
496 
497 	if (!first)
498 		return;
499 	first = 0;
500 
501 	if (nr_uarts > UART_NR)
502 		nr_uarts = UART_NR;
503 
504 	for (i = 0; i < nr_uarts; i++) {
505 		struct uart_8250_port *up = &serial8250_ports[i];
506 		struct uart_port *port = &up->port;
507 
508 		port->line = i;
509 		serial8250_init_port(up);
510 		if (!base_ops)
511 			base_ops = port->ops;
512 		port->ops = &univ8250_port_ops;
513 
514 		timer_setup(&up->timer, serial8250_timeout, 0);
515 
516 		up->ops = &univ8250_driver_ops;
517 
518 		if (IS_ENABLED(CONFIG_ALPHA_JENSEN) ||
519 		    (IS_ENABLED(CONFIG_ALPHA_GENERIC) && alpha_jensen()))
520 			port->set_mctrl = alpha_jensen_set_mctrl;
521 
522 		serial8250_set_defaults(up);
523 	}
524 
525 	/* chain base port ops to support Remote Supervisor Adapter */
526 	univ8250_port_ops = *base_ops;
527 	univ8250_rsa_support(&univ8250_port_ops);
528 
529 	if (share_irqs)
530 		irqflag = IRQF_SHARED;
531 
532 	for (i = 0, up = serial8250_ports;
533 	     i < ARRAY_SIZE(old_serial_port) && i < nr_uarts;
534 	     i++, up++) {
535 		struct uart_port *port = &up->port;
536 
537 		port->iobase   = old_serial_port[i].port;
538 		port->irq      = irq_canonicalize(old_serial_port[i].irq);
539 		port->irqflags = 0;
540 		port->uartclk  = old_serial_port[i].baud_base * 16;
541 		port->flags    = old_serial_port[i].flags;
542 		port->hub6     = 0;
543 		port->membase  = old_serial_port[i].iomem_base;
544 		port->iotype   = old_serial_port[i].io_type;
545 		port->regshift = old_serial_port[i].iomem_reg_shift;
546 
547 		port->irqflags |= irqflag;
548 		if (serial8250_isa_config != NULL)
549 			serial8250_isa_config(i, &up->port, &up->capabilities);
550 	}
551 }
552 
553 static void __init
554 serial8250_register_ports(struct uart_driver *drv, struct device *dev)
555 {
556 	int i;
557 
558 	for (i = 0; i < nr_uarts; i++) {
559 		struct uart_8250_port *up = &serial8250_ports[i];
560 
561 		if (up->port.type == PORT_8250_CIR)
562 			continue;
563 
564 		if (up->port.dev)
565 			continue;
566 
567 		up->port.dev = dev;
568 
569 		if (uart_console_registered(&up->port))
570 			pm_runtime_get_sync(up->port.dev);
571 
572 		serial8250_apply_quirks(up);
573 		uart_add_one_port(drv, &up->port);
574 	}
575 }
576 
577 #ifdef CONFIG_SERIAL_8250_CONSOLE
578 
579 static void univ8250_console_write(struct console *co, const char *s,
580 				   unsigned int count)
581 {
582 	struct uart_8250_port *up = &serial8250_ports[co->index];
583 
584 	serial8250_console_write(up, s, count);
585 }
586 
587 static int univ8250_console_setup(struct console *co, char *options)
588 {
589 	struct uart_port *port;
590 	int retval;
591 
592 	/*
593 	 * Check whether an invalid uart number has been specified, and
594 	 * if so, search for the first available port that does have
595 	 * console support.
596 	 */
597 	if (co->index >= nr_uarts)
598 		co->index = 0;
599 	port = &serial8250_ports[co->index].port;
600 	/* link port to console */
601 	port->cons = co;
602 
603 	retval = serial8250_console_setup(port, options, false);
604 	if (retval != 0)
605 		port->cons = NULL;
606 	return retval;
607 }
608 
609 static int univ8250_console_exit(struct console *co)
610 {
611 	struct uart_port *port;
612 
613 	port = &serial8250_ports[co->index].port;
614 	return serial8250_console_exit(port);
615 }
616 
617 /**
618  *	univ8250_console_match - non-standard console matching
619  *	@co:	  registering console
620  *	@name:	  name from console command line
621  *	@idx:	  index from console command line
622  *	@options: ptr to option string from console command line
623  *
624  *	Only attempts to match console command lines of the form:
625  *	    console=uart[8250],io|mmio|mmio16|mmio32,<addr>[,<options>]
626  *	    console=uart[8250],0x<addr>[,<options>]
627  *	This form is used to register an initial earlycon boot console and
628  *	replace it with the serial8250_console at 8250 driver init.
629  *
630  *	Performs console setup for a match (as required by interface)
631  *	If no <options> are specified, then assume the h/w is already setup.
632  *
633  *	Returns 0 if console matches; otherwise non-zero to use default matching
634  */
635 static int univ8250_console_match(struct console *co, char *name, int idx,
636 				  char *options)
637 {
638 	char match[] = "uart";	/* 8250-specific earlycon name */
639 	unsigned char iotype;
640 	resource_size_t addr;
641 	int i;
642 
643 	if (strncmp(name, match, 4) != 0)
644 		return -ENODEV;
645 
646 	if (uart_parse_earlycon(options, &iotype, &addr, &options))
647 		return -ENODEV;
648 
649 	/* try to match the port specified on the command line */
650 	for (i = 0; i < nr_uarts; i++) {
651 		struct uart_port *port = &serial8250_ports[i].port;
652 
653 		if (port->iotype != iotype)
654 			continue;
655 		if ((iotype == UPIO_MEM || iotype == UPIO_MEM16 ||
656 		     iotype == UPIO_MEM32 || iotype == UPIO_MEM32BE)
657 		    && (port->mapbase != addr))
658 			continue;
659 		if (iotype == UPIO_PORT && port->iobase != addr)
660 			continue;
661 
662 		co->index = i;
663 		port->cons = co;
664 		return serial8250_console_setup(port, options, true);
665 	}
666 
667 	return -ENODEV;
668 }
669 
670 static struct console univ8250_console = {
671 	.name		= "ttyS",
672 	.write		= univ8250_console_write,
673 	.device		= uart_console_device,
674 	.setup		= univ8250_console_setup,
675 	.exit		= univ8250_console_exit,
676 	.match		= univ8250_console_match,
677 	.flags		= CON_PRINTBUFFER | CON_ANYTIME,
678 	.index		= -1,
679 	.data		= &serial8250_reg,
680 };
681 
682 static int __init univ8250_console_init(void)
683 {
684 	if (nr_uarts == 0)
685 		return -ENODEV;
686 
687 	serial8250_isa_init_ports();
688 	register_console(&univ8250_console);
689 	return 0;
690 }
691 console_initcall(univ8250_console_init);
692 
693 #define SERIAL8250_CONSOLE	(&univ8250_console)
694 #else
695 #define SERIAL8250_CONSOLE	NULL
696 #endif
697 
698 static struct uart_driver serial8250_reg = {
699 	.owner			= THIS_MODULE,
700 	.driver_name		= "serial",
701 	.dev_name		= "ttyS",
702 	.major			= TTY_MAJOR,
703 	.minor			= 64,
704 	.cons			= SERIAL8250_CONSOLE,
705 };
706 
707 /*
708  * early_serial_setup - early registration for 8250 ports
709  *
710  * Setup an 8250 port structure prior to console initialisation.  Use
711  * after console initialisation will cause undefined behaviour.
712  */
713 int __init early_serial_setup(struct uart_port *port)
714 {
715 	struct uart_port *p;
716 
717 	if (port->line >= ARRAY_SIZE(serial8250_ports) || nr_uarts == 0)
718 		return -ENODEV;
719 
720 	serial8250_isa_init_ports();
721 	p = &serial8250_ports[port->line].port;
722 	p->iobase       = port->iobase;
723 	p->membase      = port->membase;
724 	p->irq          = port->irq;
725 	p->irqflags     = port->irqflags;
726 	p->uartclk      = port->uartclk;
727 	p->fifosize     = port->fifosize;
728 	p->regshift     = port->regshift;
729 	p->iotype       = port->iotype;
730 	p->flags        = port->flags;
731 	p->mapbase      = port->mapbase;
732 	p->mapsize      = port->mapsize;
733 	p->private_data = port->private_data;
734 	p->type		= port->type;
735 	p->line		= port->line;
736 
737 	serial8250_set_defaults(up_to_u8250p(p));
738 
739 	if (port->serial_in)
740 		p->serial_in = port->serial_in;
741 	if (port->serial_out)
742 		p->serial_out = port->serial_out;
743 	if (port->handle_irq)
744 		p->handle_irq = port->handle_irq;
745 
746 	return 0;
747 }
748 
749 /**
750  *	serial8250_suspend_port - suspend one serial port
751  *	@line:  serial line number
752  *
753  *	Suspend one serial port.
754  */
755 void serial8250_suspend_port(int line)
756 {
757 	struct uart_8250_port *up = &serial8250_ports[line];
758 	struct uart_port *port = &up->port;
759 
760 	if (!console_suspend_enabled && uart_console(port) &&
761 	    port->type != PORT_8250) {
762 		unsigned char canary = 0xa5;
763 
764 		serial_out(up, UART_SCR, canary);
765 		if (serial_in(up, UART_SCR) == canary)
766 			up->canary = canary;
767 	}
768 
769 	uart_suspend_port(&serial8250_reg, port);
770 }
771 EXPORT_SYMBOL(serial8250_suspend_port);
772 
773 /**
774  *	serial8250_resume_port - resume one serial port
775  *	@line:  serial line number
776  *
777  *	Resume one serial port.
778  */
779 void serial8250_resume_port(int line)
780 {
781 	struct uart_8250_port *up = &serial8250_ports[line];
782 	struct uart_port *port = &up->port;
783 
784 	up->canary = 0;
785 
786 	if (up->capabilities & UART_NATSEMI) {
787 		/* Ensure it's still in high speed mode */
788 		serial_port_out(port, UART_LCR, 0xE0);
789 
790 		ns16550a_goto_highspeed(up);
791 
792 		serial_port_out(port, UART_LCR, 0);
793 		port->uartclk = 921600*16;
794 	}
795 	uart_resume_port(&serial8250_reg, port);
796 }
797 EXPORT_SYMBOL(serial8250_resume_port);
798 
799 /*
800  * Register a set of serial devices attached to a platform device.  The
801  * list is terminated with a zero flags entry, which means we expect
802  * all entries to have at least UPF_BOOT_AUTOCONF set.
803  */
804 static int serial8250_probe(struct platform_device *dev)
805 {
806 	struct plat_serial8250_port *p = dev_get_platdata(&dev->dev);
807 	struct uart_8250_port uart;
808 	int ret, i, irqflag = 0;
809 
810 	memset(&uart, 0, sizeof(uart));
811 
812 	if (share_irqs)
813 		irqflag = IRQF_SHARED;
814 
815 	for (i = 0; p && p->flags != 0; p++, i++) {
816 		uart.port.iobase	= p->iobase;
817 		uart.port.membase	= p->membase;
818 		uart.port.irq		= p->irq;
819 		uart.port.irqflags	= p->irqflags;
820 		uart.port.uartclk	= p->uartclk;
821 		uart.port.regshift	= p->regshift;
822 		uart.port.iotype	= p->iotype;
823 		uart.port.flags		= p->flags;
824 		uart.port.mapbase	= p->mapbase;
825 		uart.port.hub6		= p->hub6;
826 		uart.port.has_sysrq	= p->has_sysrq;
827 		uart.port.private_data	= p->private_data;
828 		uart.port.type		= p->type;
829 		uart.port.serial_in	= p->serial_in;
830 		uart.port.serial_out	= p->serial_out;
831 		uart.port.handle_irq	= p->handle_irq;
832 		uart.port.handle_break	= p->handle_break;
833 		uart.port.set_termios	= p->set_termios;
834 		uart.port.set_ldisc	= p->set_ldisc;
835 		uart.port.get_mctrl	= p->get_mctrl;
836 		uart.port.pm		= p->pm;
837 		uart.port.dev		= &dev->dev;
838 		uart.port.irqflags	|= irqflag;
839 		ret = serial8250_register_8250_port(&uart);
840 		if (ret < 0) {
841 			dev_err(&dev->dev, "unable to register port at index %d "
842 				"(IO%lx MEM%llx IRQ%d): %d\n", i,
843 				p->iobase, (unsigned long long)p->mapbase,
844 				p->irq, ret);
845 		}
846 	}
847 	return 0;
848 }
849 
850 /*
851  * Remove serial ports registered against a platform device.
852  */
853 static int serial8250_remove(struct platform_device *dev)
854 {
855 	int i;
856 
857 	for (i = 0; i < nr_uarts; i++) {
858 		struct uart_8250_port *up = &serial8250_ports[i];
859 
860 		if (up->port.dev == &dev->dev)
861 			serial8250_unregister_port(i);
862 	}
863 	return 0;
864 }
865 
866 static int serial8250_suspend(struct platform_device *dev, pm_message_t state)
867 {
868 	int i;
869 
870 	for (i = 0; i < UART_NR; i++) {
871 		struct uart_8250_port *up = &serial8250_ports[i];
872 
873 		if (up->port.type != PORT_UNKNOWN && up->port.dev == &dev->dev)
874 			uart_suspend_port(&serial8250_reg, &up->port);
875 	}
876 
877 	return 0;
878 }
879 
880 static int serial8250_resume(struct platform_device *dev)
881 {
882 	int i;
883 
884 	for (i = 0; i < UART_NR; i++) {
885 		struct uart_8250_port *up = &serial8250_ports[i];
886 
887 		if (up->port.type != PORT_UNKNOWN && up->port.dev == &dev->dev)
888 			serial8250_resume_port(i);
889 	}
890 
891 	return 0;
892 }
893 
894 static struct platform_driver serial8250_isa_driver = {
895 	.probe		= serial8250_probe,
896 	.remove		= serial8250_remove,
897 	.suspend	= serial8250_suspend,
898 	.resume		= serial8250_resume,
899 	.driver		= {
900 		.name	= "serial8250",
901 	},
902 };
903 
904 /*
905  * This "device" covers _all_ ISA 8250-compatible serial devices listed
906  * in the table in include/asm/serial.h
907  */
908 static struct platform_device *serial8250_isa_devs;
909 
910 /*
911  * serial8250_register_8250_port and serial8250_unregister_port allows for
912  * 16x50 serial ports to be configured at run-time, to support PCMCIA
913  * modems and PCI multiport cards.
914  */
915 static DEFINE_MUTEX(serial_mutex);
916 
917 static struct uart_8250_port *serial8250_find_match_or_unused(const struct uart_port *port)
918 {
919 	int i;
920 
921 	/*
922 	 * First, find a port entry which matches.
923 	 */
924 	for (i = 0; i < nr_uarts; i++)
925 		if (uart_match_port(&serial8250_ports[i].port, port))
926 			return &serial8250_ports[i];
927 
928 	/* try line number first if still available */
929 	i = port->line;
930 	if (i < nr_uarts && serial8250_ports[i].port.type == PORT_UNKNOWN &&
931 			serial8250_ports[i].port.iobase == 0)
932 		return &serial8250_ports[i];
933 	/*
934 	 * We didn't find a matching entry, so look for the first
935 	 * free entry.  We look for one which hasn't been previously
936 	 * used (indicated by zero iobase).
937 	 */
938 	for (i = 0; i < nr_uarts; i++)
939 		if (serial8250_ports[i].port.type == PORT_UNKNOWN &&
940 		    serial8250_ports[i].port.iobase == 0)
941 			return &serial8250_ports[i];
942 
943 	/*
944 	 * That also failed.  Last resort is to find any entry which
945 	 * doesn't have a real port associated with it.
946 	 */
947 	for (i = 0; i < nr_uarts; i++)
948 		if (serial8250_ports[i].port.type == PORT_UNKNOWN)
949 			return &serial8250_ports[i];
950 
951 	return NULL;
952 }
953 
954 static void serial_8250_overrun_backoff_work(struct work_struct *work)
955 {
956 	struct uart_8250_port *up =
957 	    container_of(to_delayed_work(work), struct uart_8250_port,
958 			 overrun_backoff);
959 	struct uart_port *port = &up->port;
960 	unsigned long flags;
961 
962 	spin_lock_irqsave(&port->lock, flags);
963 	up->ier |= UART_IER_RLSI | UART_IER_RDI;
964 	up->port.read_status_mask |= UART_LSR_DR;
965 	serial_out(up, UART_IER, up->ier);
966 	spin_unlock_irqrestore(&port->lock, flags);
967 }
968 
969 /**
970  *	serial8250_register_8250_port - register a serial port
971  *	@up: serial port template
972  *
973  *	Configure the serial port specified by the request. If the
974  *	port exists and is in use, it is hung up and unregistered
975  *	first.
976  *
977  *	The port is then probed and if necessary the IRQ is autodetected
978  *	If this fails an error is returned.
979  *
980  *	On success the port is ready to use and the line number is returned.
981  */
982 int serial8250_register_8250_port(const struct uart_8250_port *up)
983 {
984 	struct uart_8250_port *uart;
985 	int ret = -ENOSPC;
986 
987 	if (up->port.uartclk == 0)
988 		return -EINVAL;
989 
990 	mutex_lock(&serial_mutex);
991 
992 	uart = serial8250_find_match_or_unused(&up->port);
993 	if (uart && uart->port.type != PORT_8250_CIR) {
994 		struct mctrl_gpios *gpios;
995 
996 		if (uart->port.dev)
997 			uart_remove_one_port(&serial8250_reg, &uart->port);
998 
999 		uart->port.iobase       = up->port.iobase;
1000 		uart->port.membase      = up->port.membase;
1001 		uart->port.irq          = up->port.irq;
1002 		uart->port.irqflags     = up->port.irqflags;
1003 		uart->port.uartclk      = up->port.uartclk;
1004 		uart->port.fifosize     = up->port.fifosize;
1005 		uart->port.regshift     = up->port.regshift;
1006 		uart->port.iotype       = up->port.iotype;
1007 		uart->port.flags        = up->port.flags | UPF_BOOT_AUTOCONF;
1008 		uart->bugs		= up->bugs;
1009 		uart->port.mapbase      = up->port.mapbase;
1010 		uart->port.mapsize      = up->port.mapsize;
1011 		uart->port.private_data = up->port.private_data;
1012 		uart->tx_loadsz		= up->tx_loadsz;
1013 		uart->capabilities	= up->capabilities;
1014 		uart->port.throttle	= up->port.throttle;
1015 		uart->port.unthrottle	= up->port.unthrottle;
1016 		uart->port.rs485_config	= up->port.rs485_config;
1017 		uart->port.rs485_supported = up->port.rs485_supported;
1018 		uart->port.rs485	= up->port.rs485;
1019 		uart->rs485_start_tx	= up->rs485_start_tx;
1020 		uart->rs485_stop_tx	= up->rs485_stop_tx;
1021 		uart->lsr_save_mask	= up->lsr_save_mask;
1022 		uart->dma		= up->dma;
1023 
1024 		/* Take tx_loadsz from fifosize if it wasn't set separately */
1025 		if (uart->port.fifosize && !uart->tx_loadsz)
1026 			uart->tx_loadsz = uart->port.fifosize;
1027 
1028 		if (up->port.dev) {
1029 			uart->port.dev = up->port.dev;
1030 			ret = uart_get_rs485_mode(&uart->port);
1031 			if (ret)
1032 				goto err;
1033 		}
1034 
1035 		if (up->port.flags & UPF_FIXED_TYPE)
1036 			uart->port.type = up->port.type;
1037 
1038 		/*
1039 		 * Only call mctrl_gpio_init(), if the device has no ACPI
1040 		 * companion device
1041 		 */
1042 		if (!has_acpi_companion(uart->port.dev)) {
1043 			gpios = mctrl_gpio_init(&uart->port, 0);
1044 			if (IS_ERR(gpios)) {
1045 				ret = PTR_ERR(gpios);
1046 				goto err;
1047 			} else {
1048 				uart->gpios = gpios;
1049 			}
1050 		}
1051 
1052 		serial8250_set_defaults(uart);
1053 
1054 		/* Possibly override default I/O functions.  */
1055 		if (up->port.serial_in)
1056 			uart->port.serial_in = up->port.serial_in;
1057 		if (up->port.serial_out)
1058 			uart->port.serial_out = up->port.serial_out;
1059 		if (up->port.handle_irq)
1060 			uart->port.handle_irq = up->port.handle_irq;
1061 		/*  Possibly override set_termios call */
1062 		if (up->port.set_termios)
1063 			uart->port.set_termios = up->port.set_termios;
1064 		if (up->port.set_ldisc)
1065 			uart->port.set_ldisc = up->port.set_ldisc;
1066 		if (up->port.get_mctrl)
1067 			uart->port.get_mctrl = up->port.get_mctrl;
1068 		if (up->port.set_mctrl)
1069 			uart->port.set_mctrl = up->port.set_mctrl;
1070 		if (up->port.get_divisor)
1071 			uart->port.get_divisor = up->port.get_divisor;
1072 		if (up->port.set_divisor)
1073 			uart->port.set_divisor = up->port.set_divisor;
1074 		if (up->port.startup)
1075 			uart->port.startup = up->port.startup;
1076 		if (up->port.shutdown)
1077 			uart->port.shutdown = up->port.shutdown;
1078 		if (up->port.pm)
1079 			uart->port.pm = up->port.pm;
1080 		if (up->port.handle_break)
1081 			uart->port.handle_break = up->port.handle_break;
1082 		if (up->dl_read)
1083 			uart->dl_read = up->dl_read;
1084 		if (up->dl_write)
1085 			uart->dl_write = up->dl_write;
1086 
1087 		if (uart->port.type != PORT_8250_CIR) {
1088 			if (serial8250_isa_config != NULL)
1089 				serial8250_isa_config(0, &uart->port,
1090 						&uart->capabilities);
1091 
1092 			serial8250_apply_quirks(uart);
1093 			ret = uart_add_one_port(&serial8250_reg,
1094 						&uart->port);
1095 			if (ret)
1096 				goto err;
1097 
1098 			ret = uart->port.line;
1099 		} else {
1100 			dev_info(uart->port.dev,
1101 				"skipping CIR port at 0x%lx / 0x%llx, IRQ %d\n",
1102 				uart->port.iobase,
1103 				(unsigned long long)uart->port.mapbase,
1104 				uart->port.irq);
1105 
1106 			ret = 0;
1107 		}
1108 
1109 		if (!uart->lsr_save_mask)
1110 			uart->lsr_save_mask = LSR_SAVE_FLAGS;	/* Use default LSR mask */
1111 
1112 		/* Initialise interrupt backoff work if required */
1113 		if (up->overrun_backoff_time_ms > 0) {
1114 			uart->overrun_backoff_time_ms =
1115 				up->overrun_backoff_time_ms;
1116 			INIT_DELAYED_WORK(&uart->overrun_backoff,
1117 					serial_8250_overrun_backoff_work);
1118 		} else {
1119 			uart->overrun_backoff_time_ms = 0;
1120 		}
1121 	}
1122 
1123 	mutex_unlock(&serial_mutex);
1124 
1125 	return ret;
1126 
1127 err:
1128 	uart->port.dev = NULL;
1129 	mutex_unlock(&serial_mutex);
1130 	return ret;
1131 }
1132 EXPORT_SYMBOL(serial8250_register_8250_port);
1133 
1134 /**
1135  *	serial8250_unregister_port - remove a 16x50 serial port at runtime
1136  *	@line: serial line number
1137  *
1138  *	Remove one serial port.  This may not be called from interrupt
1139  *	context.  We hand the port back to the our control.
1140  */
1141 void serial8250_unregister_port(int line)
1142 {
1143 	struct uart_8250_port *uart = &serial8250_ports[line];
1144 
1145 	mutex_lock(&serial_mutex);
1146 
1147 	if (uart->em485) {
1148 		unsigned long flags;
1149 
1150 		spin_lock_irqsave(&uart->port.lock, flags);
1151 		serial8250_em485_destroy(uart);
1152 		spin_unlock_irqrestore(&uart->port.lock, flags);
1153 	}
1154 
1155 	uart_remove_one_port(&serial8250_reg, &uart->port);
1156 	if (serial8250_isa_devs) {
1157 		uart->port.flags &= ~UPF_BOOT_AUTOCONF;
1158 		uart->port.type = PORT_UNKNOWN;
1159 		uart->port.dev = &serial8250_isa_devs->dev;
1160 		uart->capabilities = 0;
1161 		serial8250_init_port(uart);
1162 		serial8250_apply_quirks(uart);
1163 		uart_add_one_port(&serial8250_reg, &uart->port);
1164 	} else {
1165 		uart->port.dev = NULL;
1166 	}
1167 	mutex_unlock(&serial_mutex);
1168 }
1169 EXPORT_SYMBOL(serial8250_unregister_port);
1170 
1171 static int __init serial8250_init(void)
1172 {
1173 	int ret;
1174 
1175 	if (nr_uarts == 0)
1176 		return -ENODEV;
1177 
1178 	serial8250_isa_init_ports();
1179 
1180 	pr_info("Serial: 8250/16550 driver, %d ports, IRQ sharing %s\n",
1181 		nr_uarts, str_enabled_disabled(share_irqs));
1182 
1183 #ifdef CONFIG_SPARC
1184 	ret = sunserial_register_minors(&serial8250_reg, UART_NR);
1185 #else
1186 	serial8250_reg.nr = UART_NR;
1187 	ret = uart_register_driver(&serial8250_reg);
1188 #endif
1189 	if (ret)
1190 		goto out;
1191 
1192 	ret = serial8250_pnp_init();
1193 	if (ret)
1194 		goto unreg_uart_drv;
1195 
1196 	serial8250_isa_devs = platform_device_alloc("serial8250",
1197 						    PLAT8250_DEV_LEGACY);
1198 	if (!serial8250_isa_devs) {
1199 		ret = -ENOMEM;
1200 		goto unreg_pnp;
1201 	}
1202 
1203 	ret = platform_device_add(serial8250_isa_devs);
1204 	if (ret)
1205 		goto put_dev;
1206 
1207 	serial8250_register_ports(&serial8250_reg, &serial8250_isa_devs->dev);
1208 
1209 	ret = platform_driver_register(&serial8250_isa_driver);
1210 	if (ret == 0)
1211 		goto out;
1212 
1213 	platform_device_del(serial8250_isa_devs);
1214 put_dev:
1215 	platform_device_put(serial8250_isa_devs);
1216 unreg_pnp:
1217 	serial8250_pnp_exit();
1218 unreg_uart_drv:
1219 #ifdef CONFIG_SPARC
1220 	sunserial_unregister_minors(&serial8250_reg, UART_NR);
1221 #else
1222 	uart_unregister_driver(&serial8250_reg);
1223 #endif
1224 out:
1225 	return ret;
1226 }
1227 
1228 static void __exit serial8250_exit(void)
1229 {
1230 	struct platform_device *isa_dev = serial8250_isa_devs;
1231 
1232 	/*
1233 	 * This tells serial8250_unregister_port() not to re-register
1234 	 * the ports (thereby making serial8250_isa_driver permanently
1235 	 * in use.)
1236 	 */
1237 	serial8250_isa_devs = NULL;
1238 
1239 	platform_driver_unregister(&serial8250_isa_driver);
1240 	platform_device_unregister(isa_dev);
1241 
1242 	serial8250_pnp_exit();
1243 
1244 #ifdef CONFIG_SPARC
1245 	sunserial_unregister_minors(&serial8250_reg, UART_NR);
1246 #else
1247 	uart_unregister_driver(&serial8250_reg);
1248 #endif
1249 }
1250 
1251 module_init(serial8250_init);
1252 module_exit(serial8250_exit);
1253 
1254 MODULE_LICENSE("GPL");
1255 MODULE_DESCRIPTION("Generic 8250/16x50 serial driver");
1256 
1257 module_param_hw(share_irqs, uint, other, 0644);
1258 MODULE_PARM_DESC(share_irqs, "Share IRQs with other non-8250/16x50 devices (unsafe)");
1259 
1260 module_param(nr_uarts, uint, 0644);
1261 MODULE_PARM_DESC(nr_uarts, "Maximum number of UARTs supported. (1-" __MODULE_STRING(CONFIG_SERIAL_8250_NR_UARTS) ")");
1262 
1263 module_param(skip_txen_test, uint, 0644);
1264 MODULE_PARM_DESC(skip_txen_test, "Skip checking for the TXEN bug at init time");
1265 
1266 #ifdef CONFIG_SERIAL_8250_RSA
1267 module_param_hw_array(probe_rsa, ulong, ioport, &probe_rsa_count, 0444);
1268 MODULE_PARM_DESC(probe_rsa, "Probe I/O ports for RSA");
1269 #endif
1270 MODULE_ALIAS_CHARDEV_MAJOR(TTY_MAJOR);
1271 
1272 #ifdef CONFIG_SERIAL_8250_DEPRECATED_OPTIONS
1273 #ifndef MODULE
1274 /* This module was renamed to 8250_core in 3.7.  Keep the old "8250" name
1275  * working as well for the module options so we don't break people.  We
1276  * need to keep the names identical and the convenient macros will happily
1277  * refuse to let us do that by failing the build with redefinition errors
1278  * of global variables.  So we stick them inside a dummy function to avoid
1279  * those conflicts.  The options still get parsed, and the redefined
1280  * MODULE_PARAM_PREFIX lets us keep the "8250." syntax alive.
1281  *
1282  * This is hacky.  I'm sorry.
1283  */
1284 static void __used s8250_options(void)
1285 {
1286 #undef MODULE_PARAM_PREFIX
1287 #define MODULE_PARAM_PREFIX "8250_core."
1288 
1289 	module_param_cb(share_irqs, &param_ops_uint, &share_irqs, 0644);
1290 	module_param_cb(nr_uarts, &param_ops_uint, &nr_uarts, 0644);
1291 	module_param_cb(skip_txen_test, &param_ops_uint, &skip_txen_test, 0644);
1292 #ifdef CONFIG_SERIAL_8250_RSA
1293 	__module_param_call(MODULE_PARAM_PREFIX, probe_rsa,
1294 		&param_array_ops, .arr = &__param_arr_probe_rsa,
1295 		0444, -1, 0);
1296 #endif
1297 }
1298 #else
1299 MODULE_ALIAS("8250_core");
1300 #endif
1301 #endif
1302