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