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/tty.h>
27 #include <linux/ratelimit.h>
28 #include <linux/tty_flip.h>
29 #include <linux/serial.h>
30 #include <linux/serial_8250.h>
31 #include <linux/nmi.h>
32 #include <linux/mutex.h>
33 #include <linux/slab.h>
34 #include <linux/uaccess.h>
35 #include <linux/pm_runtime.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  */
serial8250_interrupt(int irq,void * dev_id)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  */
serial_do_unlink(struct irq_info * i,struct uart_8250_port * up)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 
serial_link_irq_chain(struct uart_8250_port * up)172 static int serial_link_irq_chain(struct uart_8250_port *up)
173 {
174 	struct hlist_head *h;
175 	struct hlist_node *n;
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(n, h) {
184 		i = hlist_entry(n, struct irq_info, node);
185 		if (i->irq == up->port.irq)
186 			break;
187 	}
188 
189 	if (n == NULL) {
190 		i = kzalloc(sizeof(struct irq_info), GFP_KERNEL);
191 		if (i == NULL) {
192 			mutex_unlock(&hash_mutex);
193 			return -ENOMEM;
194 		}
195 		spin_lock_init(&i->lock);
196 		i->irq = up->port.irq;
197 		hlist_add_head(&i->node, h);
198 	}
199 	mutex_unlock(&hash_mutex);
200 
201 	spin_lock_irq(&i->lock);
202 
203 	if (i->head) {
204 		list_add(&up->list, i->head);
205 		spin_unlock_irq(&i->lock);
206 
207 		ret = 0;
208 	} else {
209 		INIT_LIST_HEAD(&up->list);
210 		i->head = &up->list;
211 		spin_unlock_irq(&i->lock);
212 		ret = request_irq(up->port.irq, serial8250_interrupt,
213 				  up->port.irqflags, up->port.name, i);
214 		if (ret < 0)
215 			serial_do_unlink(i, up);
216 	}
217 
218 	return ret;
219 }
220 
serial_unlink_irq_chain(struct uart_8250_port * up)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  */
serial8250_timeout(struct timer_list * t)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 
serial8250_backup_timeout(struct timer_list * t)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 
univ8250_setup_irq(struct uart_8250_port * up)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 
univ8250_release_irq(struct uart_8250_port * up)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
serial8250_request_rsa_resource(struct uart_8250_port * up)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 
serial8250_release_rsa_resource(struct uart_8250_port * up)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  */
serial8250_get_port(int line)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 
serial8250_set_isa_configurator(void (* v)(int port,struct uart_port * up,u32 * capabilities))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 
univ8250_config_port(struct uart_port * port,int flags)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 
univ8250_request_port(struct uart_port * port)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 
univ8250_release_port(struct uart_port * port)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 
univ8250_rsa_support(struct uart_ops * ops)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 
serial8250_apply_quirks(struct uart_8250_port * up)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 
serial8250_isa_init_ports(void)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 		serial8250_set_defaults(up);
528 	}
529 
530 	/* chain base port ops to support Remote Supervisor Adapter */
531 	univ8250_port_ops = *base_ops;
532 	univ8250_rsa_support(&univ8250_port_ops);
533 
534 	if (share_irqs)
535 		irqflag = IRQF_SHARED;
536 
537 	for (i = 0, up = serial8250_ports;
538 	     i < ARRAY_SIZE(old_serial_port) && i < nr_uarts;
539 	     i++, up++) {
540 		struct uart_port *port = &up->port;
541 
542 		port->iobase   = old_serial_port[i].port;
543 		port->irq      = irq_canonicalize(old_serial_port[i].irq);
544 		port->irqflags = 0;
545 		port->uartclk  = old_serial_port[i].baud_base * 16;
546 		port->flags    = old_serial_port[i].flags;
547 		port->hub6     = 0;
548 		port->membase  = old_serial_port[i].iomem_base;
549 		port->iotype   = old_serial_port[i].io_type;
550 		port->regshift = old_serial_port[i].iomem_reg_shift;
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
serial8250_register_ports(struct uart_driver * drv,struct device * dev)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 
univ8250_console_write(struct console * co,const char * s,unsigned int count)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 
univ8250_console_setup(struct console * co,char * options)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 
univ8250_console_exit(struct console * co)611 static int univ8250_console_exit(struct console *co)
612 {
613 	struct uart_port *port;
614 
615 	port = &serial8250_ports[co->index].port;
616 	return serial8250_console_exit(port);
617 }
618 
619 /**
620  *	univ8250_console_match - non-standard console matching
621  *	@co:	  registering console
622  *	@name:	  name from console command line
623  *	@idx:	  index from console command line
624  *	@options: ptr to option string from console command line
625  *
626  *	Only attempts to match console command lines of the form:
627  *	    console=uart[8250],io|mmio|mmio16|mmio32,<addr>[,<options>]
628  *	    console=uart[8250],0x<addr>[,<options>]
629  *	This form is used to register an initial earlycon boot console and
630  *	replace it with the serial8250_console at 8250 driver init.
631  *
632  *	Performs console setup for a match (as required by interface)
633  *	If no <options> are specified, then assume the h/w is already setup.
634  *
635  *	Returns 0 if console matches; otherwise non-zero to use default matching
636  */
univ8250_console_match(struct console * co,char * name,int idx,char * options)637 static int univ8250_console_match(struct console *co, char *name, int idx,
638 				  char *options)
639 {
640 	char match[] = "uart";	/* 8250-specific earlycon name */
641 	unsigned char iotype;
642 	resource_size_t addr;
643 	int i;
644 
645 	if (strncmp(name, match, 4) != 0)
646 		return -ENODEV;
647 
648 	if (uart_parse_earlycon(options, &iotype, &addr, &options))
649 		return -ENODEV;
650 
651 	/* try to match the port specified on the command line */
652 	for (i = 0; i < nr_uarts; i++) {
653 		struct uart_port *port = &serial8250_ports[i].port;
654 
655 		if (port->iotype != iotype)
656 			continue;
657 		if ((iotype == UPIO_MEM || iotype == UPIO_MEM16 ||
658 		     iotype == UPIO_MEM32 || iotype == UPIO_MEM32BE)
659 		    && (port->mapbase != addr))
660 			continue;
661 		if (iotype == UPIO_PORT && port->iobase != addr)
662 			continue;
663 
664 		co->index = i;
665 		port->cons = co;
666 		return serial8250_console_setup(port, options, true);
667 	}
668 
669 	return -ENODEV;
670 }
671 
672 static struct console univ8250_console = {
673 	.name		= "ttyS",
674 	.write		= univ8250_console_write,
675 	.device		= uart_console_device,
676 	.setup		= univ8250_console_setup,
677 	.exit		= univ8250_console_exit,
678 	.match		= univ8250_console_match,
679 	.flags		= CON_PRINTBUFFER | CON_ANYTIME,
680 	.index		= -1,
681 	.data		= &serial8250_reg,
682 };
683 
univ8250_console_init(void)684 static int __init univ8250_console_init(void)
685 {
686 	if (nr_uarts == 0)
687 		return -ENODEV;
688 
689 	serial8250_isa_init_ports();
690 	register_console(&univ8250_console);
691 	return 0;
692 }
693 console_initcall(univ8250_console_init);
694 
695 #define SERIAL8250_CONSOLE	(&univ8250_console)
696 #else
697 #define SERIAL8250_CONSOLE	NULL
698 #endif
699 
700 static struct uart_driver serial8250_reg = {
701 	.owner			= THIS_MODULE,
702 	.driver_name		= "serial",
703 	.dev_name		= "ttyS",
704 	.major			= TTY_MAJOR,
705 	.minor			= 64,
706 	.cons			= SERIAL8250_CONSOLE,
707 };
708 
709 /*
710  * early_serial_setup - early registration for 8250 ports
711  *
712  * Setup an 8250 port structure prior to console initialisation.  Use
713  * after console initialisation will cause undefined behaviour.
714  */
early_serial_setup(struct uart_port * port)715 int __init early_serial_setup(struct uart_port *port)
716 {
717 	struct uart_port *p;
718 
719 	if (port->line >= ARRAY_SIZE(serial8250_ports) || nr_uarts == 0)
720 		return -ENODEV;
721 
722 	serial8250_isa_init_ports();
723 	p = &serial8250_ports[port->line].port;
724 	p->iobase       = port->iobase;
725 	p->membase      = port->membase;
726 	p->irq          = port->irq;
727 	p->irqflags     = port->irqflags;
728 	p->uartclk      = port->uartclk;
729 	p->fifosize     = port->fifosize;
730 	p->regshift     = port->regshift;
731 	p->iotype       = port->iotype;
732 	p->flags        = port->flags;
733 	p->mapbase      = port->mapbase;
734 	p->mapsize      = port->mapsize;
735 	p->private_data = port->private_data;
736 	p->type		= port->type;
737 	p->line		= port->line;
738 
739 	serial8250_set_defaults(up_to_u8250p(p));
740 
741 	if (port->serial_in)
742 		p->serial_in = port->serial_in;
743 	if (port->serial_out)
744 		p->serial_out = port->serial_out;
745 	if (port->handle_irq)
746 		p->handle_irq = port->handle_irq;
747 
748 	return 0;
749 }
750 
751 /**
752  *	serial8250_suspend_port - suspend one serial port
753  *	@line:  serial line number
754  *
755  *	Suspend one serial port.
756  */
serial8250_suspend_port(int line)757 void serial8250_suspend_port(int line)
758 {
759 	struct uart_8250_port *up = &serial8250_ports[line];
760 	struct uart_port *port = &up->port;
761 
762 	if (!console_suspend_enabled && uart_console(port) &&
763 	    port->type != PORT_8250) {
764 		unsigned char canary = 0xa5;
765 		serial_out(up, UART_SCR, canary);
766 		if (serial_in(up, UART_SCR) == canary)
767 			up->canary = canary;
768 	}
769 
770 	uart_suspend_port(&serial8250_reg, port);
771 }
772 EXPORT_SYMBOL(serial8250_suspend_port);
773 
774 /**
775  *	serial8250_resume_port - resume one serial port
776  *	@line:  serial line number
777  *
778  *	Resume one serial port.
779  */
serial8250_resume_port(int line)780 void serial8250_resume_port(int line)
781 {
782 	struct uart_8250_port *up = &serial8250_ports[line];
783 	struct uart_port *port = &up->port;
784 
785 	up->canary = 0;
786 
787 	if (up->capabilities & UART_NATSEMI) {
788 		/* Ensure it's still in high speed mode */
789 		serial_port_out(port, UART_LCR, 0xE0);
790 
791 		ns16550a_goto_highspeed(up);
792 
793 		serial_port_out(port, UART_LCR, 0);
794 		port->uartclk = 921600*16;
795 	}
796 	uart_resume_port(&serial8250_reg, port);
797 }
798 EXPORT_SYMBOL(serial8250_resume_port);
799 
800 /*
801  * Register a set of serial devices attached to a platform device.  The
802  * list is terminated with a zero flags entry, which means we expect
803  * all entries to have at least UPF_BOOT_AUTOCONF set.
804  */
serial8250_probe(struct platform_device * dev)805 static int serial8250_probe(struct platform_device *dev)
806 {
807 	struct plat_serial8250_port *p = dev_get_platdata(&dev->dev);
808 	struct uart_8250_port uart;
809 	int ret, i, irqflag = 0;
810 
811 	memset(&uart, 0, sizeof(uart));
812 
813 	if (share_irqs)
814 		irqflag = IRQF_SHARED;
815 
816 	for (i = 0; p && p->flags != 0; p++, i++) {
817 		uart.port.iobase	= p->iobase;
818 		uart.port.membase	= p->membase;
819 		uart.port.irq		= p->irq;
820 		uart.port.irqflags	= p->irqflags;
821 		uart.port.uartclk	= p->uartclk;
822 		uart.port.regshift	= p->regshift;
823 		uart.port.iotype	= p->iotype;
824 		uart.port.flags		= p->flags;
825 		uart.port.mapbase	= p->mapbase;
826 		uart.port.hub6		= p->hub6;
827 		uart.port.has_sysrq	= p->has_sysrq;
828 		uart.port.private_data	= p->private_data;
829 		uart.port.type		= p->type;
830 		uart.port.serial_in	= p->serial_in;
831 		uart.port.serial_out	= p->serial_out;
832 		uart.port.handle_irq	= p->handle_irq;
833 		uart.port.handle_break	= p->handle_break;
834 		uart.port.set_termios	= p->set_termios;
835 		uart.port.set_ldisc	= p->set_ldisc;
836 		uart.port.get_mctrl	= p->get_mctrl;
837 		uart.port.pm		= p->pm;
838 		uart.port.dev		= &dev->dev;
839 		uart.port.irqflags	|= irqflag;
840 		ret = serial8250_register_8250_port(&uart);
841 		if (ret < 0) {
842 			dev_err(&dev->dev, "unable to register port at index %d "
843 				"(IO%lx MEM%llx IRQ%d): %d\n", i,
844 				p->iobase, (unsigned long long)p->mapbase,
845 				p->irq, ret);
846 		}
847 	}
848 	return 0;
849 }
850 
851 /*
852  * Remove serial ports registered against a platform device.
853  */
serial8250_remove(struct platform_device * dev)854 static int serial8250_remove(struct platform_device *dev)
855 {
856 	int i;
857 
858 	for (i = 0; i < nr_uarts; i++) {
859 		struct uart_8250_port *up = &serial8250_ports[i];
860 
861 		if (up->port.dev == &dev->dev)
862 			serial8250_unregister_port(i);
863 	}
864 	return 0;
865 }
866 
serial8250_suspend(struct platform_device * dev,pm_message_t state)867 static int serial8250_suspend(struct platform_device *dev, pm_message_t state)
868 {
869 	int i;
870 
871 	for (i = 0; i < UART_NR; i++) {
872 		struct uart_8250_port *up = &serial8250_ports[i];
873 
874 		if (up->port.type != PORT_UNKNOWN && up->port.dev == &dev->dev)
875 			uart_suspend_port(&serial8250_reg, &up->port);
876 	}
877 
878 	return 0;
879 }
880 
serial8250_resume(struct platform_device * dev)881 static int serial8250_resume(struct platform_device *dev)
882 {
883 	int i;
884 
885 	for (i = 0; i < UART_NR; i++) {
886 		struct uart_8250_port *up = &serial8250_ports[i];
887 
888 		if (up->port.type != PORT_UNKNOWN && up->port.dev == &dev->dev)
889 			serial8250_resume_port(i);
890 	}
891 
892 	return 0;
893 }
894 
895 static struct platform_driver serial8250_isa_driver = {
896 	.probe		= serial8250_probe,
897 	.remove		= serial8250_remove,
898 	.suspend	= serial8250_suspend,
899 	.resume		= serial8250_resume,
900 	.driver		= {
901 		.name	= "serial8250",
902 	},
903 };
904 
905 /*
906  * This "device" covers _all_ ISA 8250-compatible serial devices listed
907  * in the table in include/asm/serial.h
908  */
909 static struct platform_device *serial8250_isa_devs;
910 
911 /*
912  * serial8250_register_8250_port and serial8250_unregister_port allows for
913  * 16x50 serial ports to be configured at run-time, to support PCMCIA
914  * modems and PCI multiport cards.
915  */
916 static DEFINE_MUTEX(serial_mutex);
917 
serial8250_find_match_or_unused(struct uart_port * port)918 static struct uart_8250_port *serial8250_find_match_or_unused(struct uart_port *port)
919 {
920 	int i;
921 
922 	/*
923 	 * First, find a port entry which matches.
924 	 */
925 	for (i = 0; i < nr_uarts; i++)
926 		if (uart_match_port(&serial8250_ports[i].port, port))
927 			return &serial8250_ports[i];
928 
929 	/* try line number first if still available */
930 	i = port->line;
931 	if (i < nr_uarts && serial8250_ports[i].port.type == PORT_UNKNOWN &&
932 			serial8250_ports[i].port.iobase == 0)
933 		return &serial8250_ports[i];
934 	/*
935 	 * We didn't find a matching entry, so look for the first
936 	 * free entry.  We look for one which hasn't been previously
937 	 * used (indicated by zero iobase).
938 	 */
939 	for (i = 0; i < nr_uarts; i++)
940 		if (serial8250_ports[i].port.type == PORT_UNKNOWN &&
941 		    serial8250_ports[i].port.iobase == 0)
942 			return &serial8250_ports[i];
943 
944 	/*
945 	 * That also failed.  Last resort is to find any entry which
946 	 * doesn't have a real port associated with it.
947 	 */
948 	for (i = 0; i < nr_uarts; i++)
949 		if (serial8250_ports[i].port.type == PORT_UNKNOWN)
950 			return &serial8250_ports[i];
951 
952 	return NULL;
953 }
954 
serial_8250_overrun_backoff_work(struct work_struct * work)955 static void serial_8250_overrun_backoff_work(struct work_struct *work)
956 {
957 	struct uart_8250_port *up =
958 	    container_of(to_delayed_work(work), struct uart_8250_port,
959 			 overrun_backoff);
960 	struct uart_port *port = &up->port;
961 	unsigned long flags;
962 
963 	spin_lock_irqsave(&port->lock, flags);
964 	up->ier |= UART_IER_RLSI | UART_IER_RDI;
965 	up->port.read_status_mask |= UART_LSR_DR;
966 	serial_out(up, UART_IER, up->ier);
967 	spin_unlock_irqrestore(&port->lock, flags);
968 }
969 
970 /**
971  *	serial8250_register_8250_port - register a serial port
972  *	@up: serial port template
973  *
974  *	Configure the serial port specified by the request. If the
975  *	port exists and is in use, it is hung up and unregistered
976  *	first.
977  *
978  *	The port is then probed and if necessary the IRQ is autodetected
979  *	If this fails an error is returned.
980  *
981  *	On success the port is ready to use and the line number is returned.
982  */
serial8250_register_8250_port(struct uart_8250_port * up)983 int serial8250_register_8250_port(struct uart_8250_port *up)
984 {
985 	struct uart_8250_port *uart;
986 	int ret = -ENOSPC;
987 
988 	if (up->port.uartclk == 0)
989 		return -EINVAL;
990 
991 	mutex_lock(&serial_mutex);
992 
993 	uart = serial8250_find_match_or_unused(&up->port);
994 	if (uart && uart->port.type != PORT_8250_CIR) {
995 		struct mctrl_gpios *gpios;
996 
997 		if (uart->port.dev)
998 			uart_remove_one_port(&serial8250_reg, &uart->port);
999 
1000 		uart->port.iobase       = up->port.iobase;
1001 		uart->port.membase      = up->port.membase;
1002 		uart->port.irq          = up->port.irq;
1003 		uart->port.irqflags     = up->port.irqflags;
1004 		uart->port.uartclk      = up->port.uartclk;
1005 		uart->port.fifosize     = up->port.fifosize;
1006 		uart->port.regshift     = up->port.regshift;
1007 		uart->port.iotype       = up->port.iotype;
1008 		uart->port.flags        = up->port.flags | UPF_BOOT_AUTOCONF;
1009 		uart->bugs		= up->bugs;
1010 		uart->port.mapbase      = up->port.mapbase;
1011 		uart->port.mapsize      = up->port.mapsize;
1012 		uart->port.private_data = up->port.private_data;
1013 		uart->tx_loadsz		= up->tx_loadsz;
1014 		uart->capabilities	= up->capabilities;
1015 		uart->port.throttle	= up->port.throttle;
1016 		uart->port.unthrottle	= up->port.unthrottle;
1017 		uart->port.rs485_config	= up->port.rs485_config;
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->dma		= up->dma;
1022 
1023 		/* Take tx_loadsz from fifosize if it wasn't set separately */
1024 		if (uart->port.fifosize && !uart->tx_loadsz)
1025 			uart->tx_loadsz = uart->port.fifosize;
1026 
1027 		if (up->port.dev) {
1028 			uart->port.dev = up->port.dev;
1029 			ret = uart_get_rs485_mode(&uart->port);
1030 			if (ret)
1031 				goto err;
1032 		}
1033 
1034 		if (up->port.flags & UPF_FIXED_TYPE)
1035 			uart->port.type = up->port.type;
1036 
1037 		/*
1038 		 * Only call mctrl_gpio_init(), if the device has no ACPI
1039 		 * companion device
1040 		 */
1041 		if (!has_acpi_companion(uart->port.dev)) {
1042 			gpios = mctrl_gpio_init(&uart->port, 0);
1043 			if (IS_ERR(gpios)) {
1044 				ret = PTR_ERR(gpios);
1045 				goto err;
1046 			} else {
1047 				uart->gpios = gpios;
1048 			}
1049 		}
1050 
1051 		serial8250_set_defaults(uart);
1052 
1053 		/* Possibly override default I/O functions.  */
1054 		if (up->port.serial_in)
1055 			uart->port.serial_in = up->port.serial_in;
1056 		if (up->port.serial_out)
1057 			uart->port.serial_out = up->port.serial_out;
1058 		if (up->port.handle_irq)
1059 			uart->port.handle_irq = up->port.handle_irq;
1060 		/*  Possibly override set_termios call */
1061 		if (up->port.set_termios)
1062 			uart->port.set_termios = up->port.set_termios;
1063 		if (up->port.set_ldisc)
1064 			uart->port.set_ldisc = up->port.set_ldisc;
1065 		if (up->port.get_mctrl)
1066 			uart->port.get_mctrl = up->port.get_mctrl;
1067 		if (up->port.set_mctrl)
1068 			uart->port.set_mctrl = up->port.set_mctrl;
1069 		if (up->port.get_divisor)
1070 			uart->port.get_divisor = up->port.get_divisor;
1071 		if (up->port.set_divisor)
1072 			uart->port.set_divisor = up->port.set_divisor;
1073 		if (up->port.startup)
1074 			uart->port.startup = up->port.startup;
1075 		if (up->port.shutdown)
1076 			uart->port.shutdown = up->port.shutdown;
1077 		if (up->port.pm)
1078 			uart->port.pm = up->port.pm;
1079 		if (up->port.handle_break)
1080 			uart->port.handle_break = up->port.handle_break;
1081 		if (up->dl_read)
1082 			uart->dl_read = up->dl_read;
1083 		if (up->dl_write)
1084 			uart->dl_write = up->dl_write;
1085 
1086 		if (uart->port.type != PORT_8250_CIR) {
1087 			if (serial8250_isa_config != NULL)
1088 				serial8250_isa_config(0, &uart->port,
1089 						&uart->capabilities);
1090 
1091 			serial8250_apply_quirks(uart);
1092 			ret = uart_add_one_port(&serial8250_reg,
1093 						&uart->port);
1094 			if (ret)
1095 				goto err;
1096 
1097 			ret = uart->port.line;
1098 		} else {
1099 			dev_info(uart->port.dev,
1100 				"skipping CIR port at 0x%lx / 0x%llx, IRQ %d\n",
1101 				uart->port.iobase,
1102 				(unsigned long long)uart->port.mapbase,
1103 				uart->port.irq);
1104 
1105 			ret = 0;
1106 		}
1107 
1108 		/* Initialise interrupt backoff work if required */
1109 		if (up->overrun_backoff_time_ms > 0) {
1110 			uart->overrun_backoff_time_ms =
1111 				up->overrun_backoff_time_ms;
1112 			INIT_DELAYED_WORK(&uart->overrun_backoff,
1113 					serial_8250_overrun_backoff_work);
1114 		} else {
1115 			uart->overrun_backoff_time_ms = 0;
1116 		}
1117 	}
1118 
1119 	mutex_unlock(&serial_mutex);
1120 
1121 	return ret;
1122 
1123 err:
1124 	uart->port.dev = NULL;
1125 	mutex_unlock(&serial_mutex);
1126 	return ret;
1127 }
1128 EXPORT_SYMBOL(serial8250_register_8250_port);
1129 
1130 /**
1131  *	serial8250_unregister_port - remove a 16x50 serial port at runtime
1132  *	@line: serial line number
1133  *
1134  *	Remove one serial port.  This may not be called from interrupt
1135  *	context.  We hand the port back to the our control.
1136  */
serial8250_unregister_port(int line)1137 void serial8250_unregister_port(int line)
1138 {
1139 	struct uart_8250_port *uart = &serial8250_ports[line];
1140 
1141 	mutex_lock(&serial_mutex);
1142 
1143 	if (uart->em485) {
1144 		unsigned long flags;
1145 
1146 		spin_lock_irqsave(&uart->port.lock, flags);
1147 		serial8250_em485_destroy(uart);
1148 		spin_unlock_irqrestore(&uart->port.lock, flags);
1149 	}
1150 
1151 	uart_remove_one_port(&serial8250_reg, &uart->port);
1152 	if (serial8250_isa_devs) {
1153 		uart->port.flags &= ~UPF_BOOT_AUTOCONF;
1154 		uart->port.type = PORT_UNKNOWN;
1155 		uart->port.dev = &serial8250_isa_devs->dev;
1156 		uart->capabilities = 0;
1157 		serial8250_apply_quirks(uart);
1158 		uart_add_one_port(&serial8250_reg, &uart->port);
1159 	} else {
1160 		uart->port.dev = NULL;
1161 	}
1162 	mutex_unlock(&serial_mutex);
1163 }
1164 EXPORT_SYMBOL(serial8250_unregister_port);
1165 
serial8250_init(void)1166 static int __init serial8250_init(void)
1167 {
1168 	int ret;
1169 
1170 	if (nr_uarts == 0)
1171 		return -ENODEV;
1172 
1173 	serial8250_isa_init_ports();
1174 
1175 	pr_info("Serial: 8250/16550 driver, %d ports, IRQ sharing %sabled\n",
1176 		nr_uarts, share_irqs ? "en" : "dis");
1177 
1178 #ifdef CONFIG_SPARC
1179 	ret = sunserial_register_minors(&serial8250_reg, UART_NR);
1180 #else
1181 	serial8250_reg.nr = UART_NR;
1182 	ret = uart_register_driver(&serial8250_reg);
1183 #endif
1184 	if (ret)
1185 		goto out;
1186 
1187 	ret = serial8250_pnp_init();
1188 	if (ret)
1189 		goto unreg_uart_drv;
1190 
1191 	serial8250_isa_devs = platform_device_alloc("serial8250",
1192 						    PLAT8250_DEV_LEGACY);
1193 	if (!serial8250_isa_devs) {
1194 		ret = -ENOMEM;
1195 		goto unreg_pnp;
1196 	}
1197 
1198 	ret = platform_device_add(serial8250_isa_devs);
1199 	if (ret)
1200 		goto put_dev;
1201 
1202 	serial8250_register_ports(&serial8250_reg, &serial8250_isa_devs->dev);
1203 
1204 	ret = platform_driver_register(&serial8250_isa_driver);
1205 	if (ret == 0)
1206 		goto out;
1207 
1208 	platform_device_del(serial8250_isa_devs);
1209 put_dev:
1210 	platform_device_put(serial8250_isa_devs);
1211 unreg_pnp:
1212 	serial8250_pnp_exit();
1213 unreg_uart_drv:
1214 #ifdef CONFIG_SPARC
1215 	sunserial_unregister_minors(&serial8250_reg, UART_NR);
1216 #else
1217 	uart_unregister_driver(&serial8250_reg);
1218 #endif
1219 out:
1220 	return ret;
1221 }
1222 
serial8250_exit(void)1223 static void __exit serial8250_exit(void)
1224 {
1225 	struct platform_device *isa_dev = serial8250_isa_devs;
1226 
1227 	/*
1228 	 * This tells serial8250_unregister_port() not to re-register
1229 	 * the ports (thereby making serial8250_isa_driver permanently
1230 	 * in use.)
1231 	 */
1232 	serial8250_isa_devs = NULL;
1233 
1234 	platform_driver_unregister(&serial8250_isa_driver);
1235 	platform_device_unregister(isa_dev);
1236 
1237 	serial8250_pnp_exit();
1238 
1239 #ifdef CONFIG_SPARC
1240 	sunserial_unregister_minors(&serial8250_reg, UART_NR);
1241 #else
1242 	uart_unregister_driver(&serial8250_reg);
1243 #endif
1244 }
1245 
1246 module_init(serial8250_init);
1247 module_exit(serial8250_exit);
1248 
1249 MODULE_LICENSE("GPL");
1250 MODULE_DESCRIPTION("Generic 8250/16x50 serial driver");
1251 
1252 module_param_hw(share_irqs, uint, other, 0644);
1253 MODULE_PARM_DESC(share_irqs, "Share IRQs with other non-8250/16x50 devices (unsafe)");
1254 
1255 module_param(nr_uarts, uint, 0644);
1256 MODULE_PARM_DESC(nr_uarts, "Maximum number of UARTs supported. (1-" __MODULE_STRING(CONFIG_SERIAL_8250_NR_UARTS) ")");
1257 
1258 module_param(skip_txen_test, uint, 0644);
1259 MODULE_PARM_DESC(skip_txen_test, "Skip checking for the TXEN bug at init time");
1260 
1261 #ifdef CONFIG_SERIAL_8250_RSA
1262 module_param_hw_array(probe_rsa, ulong, ioport, &probe_rsa_count, 0444);
1263 MODULE_PARM_DESC(probe_rsa, "Probe I/O ports for RSA");
1264 #endif
1265 MODULE_ALIAS_CHARDEV_MAJOR(TTY_MAJOR);
1266 
1267 #ifdef CONFIG_SERIAL_8250_DEPRECATED_OPTIONS
1268 #ifndef MODULE
1269 /* This module was renamed to 8250_core in 3.7.  Keep the old "8250" name
1270  * working as well for the module options so we don't break people.  We
1271  * need to keep the names identical and the convenient macros will happily
1272  * refuse to let us do that by failing the build with redefinition errors
1273  * of global variables.  So we stick them inside a dummy function to avoid
1274  * those conflicts.  The options still get parsed, and the redefined
1275  * MODULE_PARAM_PREFIX lets us keep the "8250." syntax alive.
1276  *
1277  * This is hacky.  I'm sorry.
1278  */
s8250_options(void)1279 static void __used s8250_options(void)
1280 {
1281 #undef MODULE_PARAM_PREFIX
1282 #define MODULE_PARAM_PREFIX "8250_core."
1283 
1284 	module_param_cb(share_irqs, &param_ops_uint, &share_irqs, 0644);
1285 	module_param_cb(nr_uarts, &param_ops_uint, &nr_uarts, 0644);
1286 	module_param_cb(skip_txen_test, &param_ops_uint, &skip_txen_test, 0644);
1287 #ifdef CONFIG_SERIAL_8250_RSA
1288 	__module_param_call(MODULE_PARAM_PREFIX, probe_rsa,
1289 		&param_array_ops, .arr = &__param_arr_probe_rsa,
1290 		0444, -1, 0);
1291 #endif
1292 }
1293 #else
1294 MODULE_ALIAS("8250_core");
1295 #endif
1296 #endif
1297