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:
10 * early_serial_setup() ports
11 * userspace-configurable "phantom" ports
12 * serial8250_register_8250_port() ports
13 */
14
15 #include <linux/acpi.h>
16 #include <linux/module.h>
17 #include <linux/moduleparam.h>
18 #include <linux/ioport.h>
19 #include <linux/init.h>
20 #include <linux/console.h>
21 #include <linux/sysrq.h>
22 #include <linux/delay.h>
23 #include <linux/platform_device.h>
24 #include <linux/pm_runtime.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/string_helpers.h>
34 #include <linux/uaccess.h>
35 #include <linux/io.h>
36
37 #include <asm/irq.h>
38
39 #include "8250.h"
40
41 #define PASS_LIMIT 512
42
43 struct irq_info {
44 struct hlist_node node;
45 int irq;
46 spinlock_t lock; /* Protects list not the hash */
47 struct list_head *head;
48 };
49
50 #define NR_IRQ_HASH 32 /* Can be adjusted later */
51 static struct hlist_head irq_lists[NR_IRQ_HASH];
52 static DEFINE_MUTEX(hash_mutex); /* Used to walk the hash */
53
54 /*
55 * This is the serial driver's interrupt routine.
56 *
57 * Arjan thinks the old way was overly complex, so it got simplified.
58 * Alan disagrees, saying that need the complexity to handle the weird
59 * nature of ISA shared interrupts. (This is a special exception.)
60 *
61 * In order to handle ISA shared interrupts properly, we need to check
62 * that all ports have been serviced, and therefore the ISA interrupt
63 * line has been de-asserted.
64 *
65 * This means we need to loop through all ports. checking that they
66 * don't have an interrupt pending.
67 */
serial8250_interrupt(int irq,void * dev_id)68 static irqreturn_t serial8250_interrupt(int irq, void *dev_id)
69 {
70 struct irq_info *i = dev_id;
71 struct list_head *l, *end = NULL;
72 int pass_counter = 0, handled = 0;
73
74 pr_debug("%s(%d): start\n", __func__, irq);
75
76 spin_lock(&i->lock);
77
78 l = i->head;
79 do {
80 struct uart_8250_port *up;
81 struct uart_port *port;
82
83 up = list_entry(l, struct uart_8250_port, list);
84 port = &up->port;
85
86 if (port->handle_irq(port)) {
87 handled = 1;
88 end = NULL;
89 } else if (end == NULL)
90 end = l;
91
92 l = l->next;
93
94 if (l == i->head && pass_counter++ > PASS_LIMIT)
95 break;
96 } while (l != end);
97
98 spin_unlock(&i->lock);
99
100 pr_debug("%s(%d): end\n", __func__, irq);
101
102 return IRQ_RETVAL(handled);
103 }
104
105 /*
106 * To support ISA shared interrupts, we need to have one interrupt
107 * handler that ensures that the IRQ line has been deasserted
108 * before returning. Failing to do this will result in the IRQ
109 * line being stuck active, and, since ISA irqs are edge triggered,
110 * no more IRQs will be seen.
111 */
serial_do_unlink(struct irq_info * i,struct uart_8250_port * up)112 static void serial_do_unlink(struct irq_info *i, struct uart_8250_port *up)
113 {
114 spin_lock_irq(&i->lock);
115
116 if (!list_empty(i->head)) {
117 if (i->head == &up->list)
118 i->head = i->head->next;
119 list_del(&up->list);
120 } else {
121 BUG_ON(i->head != &up->list);
122 i->head = NULL;
123 }
124 spin_unlock_irq(&i->lock);
125 /* List empty so throw away the hash node */
126 if (i->head == NULL) {
127 hlist_del(&i->node);
128 kfree(i);
129 }
130 }
131
serial_link_irq_chain(struct uart_8250_port * up)132 static int serial_link_irq_chain(struct uart_8250_port *up)
133 {
134 struct hlist_head *h;
135 struct irq_info *i;
136 int ret;
137
138 mutex_lock(&hash_mutex);
139
140 h = &irq_lists[up->port.irq % NR_IRQ_HASH];
141
142 hlist_for_each_entry(i, h, node)
143 if (i->irq == up->port.irq)
144 break;
145
146 if (i == NULL) {
147 i = kzalloc(sizeof(struct irq_info), GFP_KERNEL);
148 if (i == NULL) {
149 mutex_unlock(&hash_mutex);
150 return -ENOMEM;
151 }
152 spin_lock_init(&i->lock);
153 i->irq = up->port.irq;
154 hlist_add_head(&i->node, h);
155 }
156 mutex_unlock(&hash_mutex);
157
158 spin_lock_irq(&i->lock);
159
160 if (i->head) {
161 list_add(&up->list, i->head);
162 spin_unlock_irq(&i->lock);
163
164 ret = 0;
165 } else {
166 INIT_LIST_HEAD(&up->list);
167 i->head = &up->list;
168 spin_unlock_irq(&i->lock);
169 ret = request_irq(up->port.irq, serial8250_interrupt,
170 up->port.irqflags, up->port.name, i);
171 if (ret < 0)
172 serial_do_unlink(i, up);
173 }
174
175 return ret;
176 }
177
serial_unlink_irq_chain(struct uart_8250_port * up)178 static void serial_unlink_irq_chain(struct uart_8250_port *up)
179 {
180 struct irq_info *i;
181 struct hlist_head *h;
182
183 mutex_lock(&hash_mutex);
184
185 h = &irq_lists[up->port.irq % NR_IRQ_HASH];
186
187 hlist_for_each_entry(i, h, node)
188 if (i->irq == up->port.irq)
189 break;
190
191 BUG_ON(i == NULL);
192 BUG_ON(i->head == NULL);
193
194 if (list_empty(i->head))
195 free_irq(up->port.irq, i);
196
197 serial_do_unlink(i, up);
198 mutex_unlock(&hash_mutex);
199 }
200
201 /*
202 * This function is used to handle ports that do not have an
203 * interrupt. This doesn't work very well for 16450's, but gives
204 * barely passable results for a 16550A. (Although at the expense
205 * of much CPU overhead).
206 */
serial8250_timeout(struct timer_list * t)207 static void serial8250_timeout(struct timer_list *t)
208 {
209 struct uart_8250_port *up = from_timer(up, t, timer);
210
211 up->port.handle_irq(&up->port);
212 mod_timer(&up->timer, jiffies + uart_poll_timeout(&up->port));
213 }
214
serial8250_backup_timeout(struct timer_list * t)215 static void serial8250_backup_timeout(struct timer_list *t)
216 {
217 struct uart_8250_port *up = from_timer(up, t, timer);
218 unsigned int iir, ier = 0, lsr;
219 unsigned long flags;
220
221 uart_port_lock_irqsave(&up->port, &flags);
222
223 /*
224 * Must disable interrupts or else we risk racing with the interrupt
225 * based handler.
226 */
227 if (up->port.irq) {
228 ier = serial_in(up, UART_IER);
229 serial_out(up, UART_IER, 0);
230 }
231
232 iir = serial_in(up, UART_IIR);
233
234 /*
235 * This should be a safe test for anyone who doesn't trust the
236 * IIR bits on their UART, but it's specifically designed for
237 * the "Diva" UART used on the management processor on many HP
238 * ia64 and parisc boxes.
239 */
240 lsr = serial_lsr_in(up);
241 if ((iir & UART_IIR_NO_INT) && (up->ier & UART_IER_THRI) &&
242 (!kfifo_is_empty(&up->port.state->port.xmit_fifo) ||
243 up->port.x_char) &&
244 (lsr & UART_LSR_THRE)) {
245 iir &= ~(UART_IIR_ID | UART_IIR_NO_INT);
246 iir |= UART_IIR_THRI;
247 }
248
249 if (!(iir & UART_IIR_NO_INT))
250 serial8250_tx_chars(up);
251
252 if (up->port.irq)
253 serial_out(up, UART_IER, ier);
254
255 uart_port_unlock_irqrestore(&up->port, flags);
256
257 /* Standard timer interval plus 0.2s to keep the port running */
258 mod_timer(&up->timer,
259 jiffies + uart_poll_timeout(&up->port) + HZ / 5);
260 }
261
univ8250_setup_timer(struct uart_8250_port * up)262 static void univ8250_setup_timer(struct uart_8250_port *up)
263 {
264 struct uart_port *port = &up->port;
265
266 /*
267 * The above check will only give an accurate result the first time
268 * the port is opened so this value needs to be preserved.
269 */
270 if (up->bugs & UART_BUG_THRE) {
271 pr_debug("%s - using backup timer\n", port->name);
272
273 up->timer.function = serial8250_backup_timeout;
274 mod_timer(&up->timer, jiffies +
275 uart_poll_timeout(port) + HZ / 5);
276 }
277
278 /*
279 * If the "interrupt" for this port doesn't correspond with any
280 * hardware interrupt, we use a timer-based system. The original
281 * driver used to do this with IRQ0.
282 */
283 if (!port->irq)
284 mod_timer(&up->timer, jiffies + uart_poll_timeout(port));
285 }
286
univ8250_setup_irq(struct uart_8250_port * up)287 static int univ8250_setup_irq(struct uart_8250_port *up)
288 {
289 struct uart_port *port = &up->port;
290
291 if (port->irq)
292 return serial_link_irq_chain(up);
293
294 return 0;
295 }
296
univ8250_release_irq(struct uart_8250_port * up)297 static void univ8250_release_irq(struct uart_8250_port *up)
298 {
299 struct uart_port *port = &up->port;
300
301 del_timer_sync(&up->timer);
302 up->timer.function = serial8250_timeout;
303 if (port->irq)
304 serial_unlink_irq_chain(up);
305 }
306
307 const struct uart_ops *univ8250_port_base_ops = NULL;
308 struct uart_ops univ8250_port_ops;
309
310 static const struct uart_8250_ops univ8250_driver_ops = {
311 .setup_irq = univ8250_setup_irq,
312 .release_irq = univ8250_release_irq,
313 .setup_timer = univ8250_setup_timer,
314 };
315
316 static struct uart_8250_port serial8250_ports[UART_NR];
317
318 /**
319 * serial8250_get_port - retrieve struct uart_8250_port
320 * @line: serial line number
321 *
322 * This function retrieves struct uart_8250_port for the specific line.
323 * This struct *must* *not* be used to perform a 8250 or serial core operation
324 * which is not accessible otherwise. Its only purpose is to make the struct
325 * accessible to the runtime-pm callbacks for context suspend/restore.
326 * The lock assumption made here is none because runtime-pm suspend/resume
327 * callbacks should not be invoked if there is any operation performed on the
328 * port.
329 */
serial8250_get_port(int line)330 struct uart_8250_port *serial8250_get_port(int line)
331 {
332 return &serial8250_ports[line];
333 }
334 EXPORT_SYMBOL_GPL(serial8250_get_port);
335
serial8250_apply_quirks(struct uart_8250_port * up)336 static inline void serial8250_apply_quirks(struct uart_8250_port *up)
337 {
338 up->port.quirks |= skip_txen_test ? UPQ_NO_TXEN_TEST : 0;
339 }
340
serial8250_setup_port(int index)341 struct uart_8250_port *serial8250_setup_port(int index)
342 {
343 struct uart_8250_port *up;
344
345 if (index >= UART_NR)
346 return NULL;
347
348 up = &serial8250_ports[index];
349 up->port.line = index;
350 up->port.port_id = index;
351
352 serial8250_init_port(up);
353 if (!univ8250_port_base_ops)
354 univ8250_port_base_ops = up->port.ops;
355 up->port.ops = &univ8250_port_ops;
356
357 timer_setup(&up->timer, serial8250_timeout, 0);
358
359 up->ops = &univ8250_driver_ops;
360
361 serial8250_set_defaults(up);
362
363 return up;
364 }
365
serial8250_register_ports(struct uart_driver * drv,struct device * dev)366 void __init serial8250_register_ports(struct uart_driver *drv, struct device *dev)
367 {
368 int i;
369
370 for (i = 0; i < nr_uarts; i++) {
371 struct uart_8250_port *up = &serial8250_ports[i];
372
373 if (up->port.type == PORT_8250_CIR)
374 continue;
375
376 if (up->port.dev)
377 continue;
378
379 up->port.dev = dev;
380
381 if (uart_console_registered(&up->port))
382 pm_runtime_get_sync(up->port.dev);
383
384 serial8250_apply_quirks(up);
385 uart_add_one_port(drv, &up->port);
386 }
387 }
388
389 #ifdef CONFIG_SERIAL_8250_CONSOLE
390
univ8250_console_write(struct console * co,const char * s,unsigned int count)391 static void univ8250_console_write(struct console *co, const char *s,
392 unsigned int count)
393 {
394 struct uart_8250_port *up = &serial8250_ports[co->index];
395
396 serial8250_console_write(up, s, count);
397 }
398
univ8250_console_setup(struct console * co,char * options)399 static int univ8250_console_setup(struct console *co, char *options)
400 {
401 struct uart_8250_port *up;
402 struct uart_port *port;
403 int retval, i;
404
405 /*
406 * Check whether an invalid uart number has been specified, and
407 * if so, search for the first available port that does have
408 * console support.
409 */
410 if (co->index < 0 || co->index >= UART_NR)
411 co->index = 0;
412
413 /*
414 * If the console is past the initial isa ports, init more ports up to
415 * co->index as needed and increment nr_uarts accordingly.
416 */
417 for (i = nr_uarts; i <= co->index; i++) {
418 up = serial8250_setup_port(i);
419 if (!up)
420 return -ENODEV;
421 nr_uarts++;
422 }
423
424 port = &serial8250_ports[co->index].port;
425 /* link port to console */
426 uart_port_set_cons(port, co);
427
428 retval = serial8250_console_setup(port, options, false);
429 if (retval != 0)
430 uart_port_set_cons(port, NULL);
431 return retval;
432 }
433
univ8250_console_exit(struct console * co)434 static int univ8250_console_exit(struct console *co)
435 {
436 struct uart_port *port;
437
438 port = &serial8250_ports[co->index].port;
439 return serial8250_console_exit(port);
440 }
441
442 /**
443 * univ8250_console_match - non-standard console matching
444 * @co: registering console
445 * @name: name from console command line
446 * @idx: index from console command line
447 * @options: ptr to option string from console command line
448 *
449 * Only attempts to match console command lines of the form:
450 * console=uart[8250],io|mmio|mmio16|mmio32,<addr>[,<options>]
451 * console=uart[8250],0x<addr>[,<options>]
452 * This form is used to register an initial earlycon boot console and
453 * replace it with the serial8250_console at 8250 driver init.
454 *
455 * Performs console setup for a match (as required by interface)
456 * If no <options> are specified, then assume the h/w is already setup.
457 *
458 * Returns 0 if console matches; otherwise non-zero to use default matching
459 */
univ8250_console_match(struct console * co,char * name,int idx,char * options)460 static int univ8250_console_match(struct console *co, char *name, int idx,
461 char *options)
462 {
463 char match[] = "uart"; /* 8250-specific earlycon name */
464 unsigned char iotype;
465 resource_size_t addr;
466 int i;
467
468 if (strncmp(name, match, 4) != 0)
469 return -ENODEV;
470
471 if (uart_parse_earlycon(options, &iotype, &addr, &options))
472 return -ENODEV;
473
474 /* try to match the port specified on the command line */
475 for (i = 0; i < nr_uarts; i++) {
476 struct uart_port *port = &serial8250_ports[i].port;
477
478 if (port->iotype != iotype)
479 continue;
480 if ((iotype == UPIO_MEM || iotype == UPIO_MEM16 ||
481 iotype == UPIO_MEM32 || iotype == UPIO_MEM32BE)
482 && (port->mapbase != addr))
483 continue;
484 if (iotype == UPIO_PORT && port->iobase != addr)
485 continue;
486
487 co->index = i;
488 uart_port_set_cons(port, co);
489 return serial8250_console_setup(port, options, true);
490 }
491
492 return -ENODEV;
493 }
494
495 static struct console univ8250_console = {
496 .name = "ttyS",
497 .write = univ8250_console_write,
498 .device = uart_console_device,
499 .setup = univ8250_console_setup,
500 .exit = univ8250_console_exit,
501 .match = univ8250_console_match,
502 .flags = CON_PRINTBUFFER | CON_ANYTIME,
503 .index = -1,
504 .data = &serial8250_reg,
505 };
506
univ8250_console_init(void)507 static int __init univ8250_console_init(void)
508 {
509 if (nr_uarts == 0)
510 return -ENODEV;
511
512 serial8250_isa_init_ports();
513 register_console(&univ8250_console);
514 return 0;
515 }
516 console_initcall(univ8250_console_init);
517
518 #define SERIAL8250_CONSOLE (&univ8250_console)
519 #else
520 #define SERIAL8250_CONSOLE NULL
521 #endif
522
523 struct uart_driver serial8250_reg = {
524 .owner = THIS_MODULE,
525 .driver_name = "serial",
526 .dev_name = "ttyS",
527 .major = TTY_MAJOR,
528 .minor = 64,
529 .cons = SERIAL8250_CONSOLE,
530 };
531
532 /*
533 * early_serial_setup - early registration for 8250 ports
534 *
535 * Setup an 8250 port structure prior to console initialisation. Use
536 * after console initialisation will cause undefined behaviour.
537 */
early_serial_setup(struct uart_port * port)538 int __init early_serial_setup(struct uart_port *port)
539 {
540 struct uart_port *p;
541
542 if (port->line >= ARRAY_SIZE(serial8250_ports) || nr_uarts == 0)
543 return -ENODEV;
544
545 serial8250_isa_init_ports();
546 p = &serial8250_ports[port->line].port;
547 p->iobase = port->iobase;
548 p->membase = port->membase;
549 p->irq = port->irq;
550 p->irqflags = port->irqflags;
551 p->uartclk = port->uartclk;
552 p->fifosize = port->fifosize;
553 p->regshift = port->regshift;
554 p->iotype = port->iotype;
555 p->flags = port->flags;
556 p->mapbase = port->mapbase;
557 p->mapsize = port->mapsize;
558 p->private_data = port->private_data;
559 p->type = port->type;
560 p->line = port->line;
561
562 serial8250_set_defaults(up_to_u8250p(p));
563
564 if (port->serial_in)
565 p->serial_in = port->serial_in;
566 if (port->serial_out)
567 p->serial_out = port->serial_out;
568 if (port->handle_irq)
569 p->handle_irq = port->handle_irq;
570
571 return 0;
572 }
573
574 /**
575 * serial8250_suspend_port - suspend one serial port
576 * @line: serial line number
577 *
578 * Suspend one serial port.
579 */
serial8250_suspend_port(int line)580 void serial8250_suspend_port(int line)
581 {
582 struct uart_8250_port *up = &serial8250_ports[line];
583 struct uart_port *port = &up->port;
584
585 if (!console_suspend_enabled && uart_console(port) &&
586 port->type != PORT_8250) {
587 unsigned char canary = 0xa5;
588
589 serial_out(up, UART_SCR, canary);
590 if (serial_in(up, UART_SCR) == canary)
591 up->canary = canary;
592 }
593
594 uart_suspend_port(&serial8250_reg, port);
595 }
596 EXPORT_SYMBOL(serial8250_suspend_port);
597
598 /**
599 * serial8250_resume_port - resume one serial port
600 * @line: serial line number
601 *
602 * Resume one serial port.
603 */
serial8250_resume_port(int line)604 void serial8250_resume_port(int line)
605 {
606 struct uart_8250_port *up = &serial8250_ports[line];
607 struct uart_port *port = &up->port;
608
609 up->canary = 0;
610
611 if (up->capabilities & UART_NATSEMI) {
612 /* Ensure it's still in high speed mode */
613 serial_port_out(port, UART_LCR, 0xE0);
614
615 ns16550a_goto_highspeed(up);
616
617 serial_port_out(port, UART_LCR, 0);
618 port->uartclk = 921600*16;
619 }
620 uart_resume_port(&serial8250_reg, port);
621 }
622 EXPORT_SYMBOL(serial8250_resume_port);
623
624 /*
625 * serial8250_register_8250_port and serial8250_unregister_port allows for
626 * 16x50 serial ports to be configured at run-time, to support PCMCIA
627 * modems and PCI multiport cards.
628 */
629 static DEFINE_MUTEX(serial_mutex);
630
serial8250_find_match_or_unused(const struct uart_port * port)631 static struct uart_8250_port *serial8250_find_match_or_unused(const struct uart_port *port)
632 {
633 int i;
634
635 /*
636 * First, find a port entry which matches.
637 */
638 for (i = 0; i < nr_uarts; i++)
639 if (uart_match_port(&serial8250_ports[i].port, port))
640 return &serial8250_ports[i];
641
642 /* try line number first if still available */
643 i = port->line;
644 if (i < nr_uarts && serial8250_ports[i].port.type == PORT_UNKNOWN &&
645 serial8250_ports[i].port.iobase == 0)
646 return &serial8250_ports[i];
647 /*
648 * We didn't find a matching entry, so look for the first
649 * free entry. We look for one which hasn't been previously
650 * used (indicated by zero iobase).
651 */
652 for (i = 0; i < nr_uarts; i++)
653 if (serial8250_ports[i].port.type == PORT_UNKNOWN &&
654 serial8250_ports[i].port.iobase == 0)
655 return &serial8250_ports[i];
656
657 /*
658 * That also failed. Last resort is to find any entry which
659 * doesn't have a real port associated with it.
660 */
661 for (i = 0; i < nr_uarts; i++)
662 if (serial8250_ports[i].port.type == PORT_UNKNOWN)
663 return &serial8250_ports[i];
664
665 return NULL;
666 }
667
serial_8250_overrun_backoff_work(struct work_struct * work)668 static void serial_8250_overrun_backoff_work(struct work_struct *work)
669 {
670 struct uart_8250_port *up =
671 container_of(to_delayed_work(work), struct uart_8250_port,
672 overrun_backoff);
673 struct uart_port *port = &up->port;
674 unsigned long flags;
675
676 uart_port_lock_irqsave(port, &flags);
677 up->ier |= UART_IER_RLSI | UART_IER_RDI;
678 up->port.read_status_mask |= UART_LSR_DR;
679 serial_out(up, UART_IER, up->ier);
680 uart_port_unlock_irqrestore(port, flags);
681 }
682
683 /**
684 * serial8250_register_8250_port - register a serial port
685 * @up: serial port template
686 *
687 * Configure the serial port specified by the request. If the
688 * port exists and is in use, it is hung up and unregistered
689 * first.
690 *
691 * The port is then probed and if necessary the IRQ is autodetected
692 * If this fails an error is returned.
693 *
694 * On success the port is ready to use and the line number is returned.
695 */
serial8250_register_8250_port(const struct uart_8250_port * up)696 int serial8250_register_8250_port(const struct uart_8250_port *up)
697 {
698 struct uart_8250_port *uart;
699 int ret = -ENOSPC;
700
701 if (up->port.uartclk == 0)
702 return -EINVAL;
703
704 mutex_lock(&serial_mutex);
705
706 uart = serial8250_find_match_or_unused(&up->port);
707 if (!uart) {
708 /*
709 * If the port is past the initial isa ports, initialize a new
710 * port and increment nr_uarts accordingly.
711 */
712 uart = serial8250_setup_port(nr_uarts);
713 if (!uart)
714 goto unlock;
715 nr_uarts++;
716 }
717
718 if (uart->port.type != PORT_8250_CIR) {
719 struct mctrl_gpios *gpios;
720
721 if (uart->port.dev)
722 uart_remove_one_port(&serial8250_reg, &uart->port);
723
724 uart->port.ctrl_id = up->port.ctrl_id;
725 uart->port.port_id = up->port.port_id;
726 uart->port.iobase = up->port.iobase;
727 uart->port.membase = up->port.membase;
728 uart->port.irq = up->port.irq;
729 uart->port.irqflags = up->port.irqflags;
730 uart->port.uartclk = up->port.uartclk;
731 uart->port.fifosize = up->port.fifosize;
732 uart->port.regshift = up->port.regshift;
733 uart->port.iotype = up->port.iotype;
734 uart->port.flags = up->port.flags | UPF_BOOT_AUTOCONF;
735 uart->bugs = up->bugs;
736 uart->port.mapbase = up->port.mapbase;
737 uart->port.mapsize = up->port.mapsize;
738 uart->port.private_data = up->port.private_data;
739 uart->tx_loadsz = up->tx_loadsz;
740 uart->capabilities = up->capabilities;
741 uart->port.throttle = up->port.throttle;
742 uart->port.unthrottle = up->port.unthrottle;
743 uart->port.rs485_config = up->port.rs485_config;
744 uart->port.rs485_supported = up->port.rs485_supported;
745 uart->port.rs485 = up->port.rs485;
746 uart->rs485_start_tx = up->rs485_start_tx;
747 uart->rs485_stop_tx = up->rs485_stop_tx;
748 uart->lsr_save_mask = up->lsr_save_mask;
749 uart->dma = up->dma;
750
751 /* Take tx_loadsz from fifosize if it wasn't set separately */
752 if (uart->port.fifosize && !uart->tx_loadsz)
753 uart->tx_loadsz = uart->port.fifosize;
754
755 if (up->port.dev) {
756 uart->port.dev = up->port.dev;
757 ret = uart_get_rs485_mode(&uart->port);
758 if (ret)
759 goto err;
760 }
761
762 if (up->port.flags & UPF_FIXED_TYPE)
763 uart->port.type = up->port.type;
764
765 /*
766 * Only call mctrl_gpio_init(), if the device has no ACPI
767 * companion device
768 */
769 if (!has_acpi_companion(uart->port.dev)) {
770 gpios = mctrl_gpio_init(&uart->port, 0);
771 if (IS_ERR(gpios)) {
772 ret = PTR_ERR(gpios);
773 goto err;
774 } else {
775 uart->gpios = gpios;
776 }
777 }
778
779 serial8250_set_defaults(uart);
780
781 /* Possibly override default I/O functions. */
782 if (up->port.serial_in)
783 uart->port.serial_in = up->port.serial_in;
784 if (up->port.serial_out)
785 uart->port.serial_out = up->port.serial_out;
786 if (up->port.handle_irq)
787 uart->port.handle_irq = up->port.handle_irq;
788 /* Possibly override set_termios call */
789 if (up->port.set_termios)
790 uart->port.set_termios = up->port.set_termios;
791 if (up->port.set_ldisc)
792 uart->port.set_ldisc = up->port.set_ldisc;
793 if (up->port.get_mctrl)
794 uart->port.get_mctrl = up->port.get_mctrl;
795 if (up->port.set_mctrl)
796 uart->port.set_mctrl = up->port.set_mctrl;
797 if (up->port.get_divisor)
798 uart->port.get_divisor = up->port.get_divisor;
799 if (up->port.set_divisor)
800 uart->port.set_divisor = up->port.set_divisor;
801 if (up->port.startup)
802 uart->port.startup = up->port.startup;
803 if (up->port.shutdown)
804 uart->port.shutdown = up->port.shutdown;
805 if (up->port.pm)
806 uart->port.pm = up->port.pm;
807 if (up->port.handle_break)
808 uart->port.handle_break = up->port.handle_break;
809 if (up->dl_read)
810 uart->dl_read = up->dl_read;
811 if (up->dl_write)
812 uart->dl_write = up->dl_write;
813
814 if (uart->port.type != PORT_8250_CIR) {
815 if (serial8250_isa_config != NULL)
816 serial8250_isa_config(0, &uart->port,
817 &uart->capabilities);
818
819 serial8250_apply_quirks(uart);
820 ret = uart_add_one_port(&serial8250_reg,
821 &uart->port);
822 if (ret)
823 goto err;
824
825 ret = uart->port.line;
826 } else {
827 dev_info(uart->port.dev,
828 "skipping CIR port at 0x%lx / 0x%llx, IRQ %d\n",
829 uart->port.iobase,
830 (unsigned long long)uart->port.mapbase,
831 uart->port.irq);
832
833 ret = 0;
834 }
835
836 if (!uart->lsr_save_mask)
837 uart->lsr_save_mask = LSR_SAVE_FLAGS; /* Use default LSR mask */
838
839 /* Initialise interrupt backoff work if required */
840 if (up->overrun_backoff_time_ms > 0) {
841 uart->overrun_backoff_time_ms =
842 up->overrun_backoff_time_ms;
843 INIT_DELAYED_WORK(&uart->overrun_backoff,
844 serial_8250_overrun_backoff_work);
845 } else {
846 uart->overrun_backoff_time_ms = 0;
847 }
848 }
849
850 unlock:
851 mutex_unlock(&serial_mutex);
852
853 return ret;
854
855 err:
856 uart->port.dev = NULL;
857 mutex_unlock(&serial_mutex);
858 return ret;
859 }
860 EXPORT_SYMBOL(serial8250_register_8250_port);
861
862 /**
863 * serial8250_unregister_port - remove a 16x50 serial port at runtime
864 * @line: serial line number
865 *
866 * Remove one serial port. This may not be called from interrupt
867 * context. We hand the port back to the our control.
868 */
serial8250_unregister_port(int line)869 void serial8250_unregister_port(int line)
870 {
871 struct uart_8250_port *uart = &serial8250_ports[line];
872
873 mutex_lock(&serial_mutex);
874
875 if (uart->em485) {
876 unsigned long flags;
877
878 uart_port_lock_irqsave(&uart->port, &flags);
879 serial8250_em485_destroy(uart);
880 uart_port_unlock_irqrestore(&uart->port, flags);
881 }
882
883 uart_remove_one_port(&serial8250_reg, &uart->port);
884 if (serial8250_isa_devs) {
885 uart->port.flags &= ~UPF_BOOT_AUTOCONF;
886 uart->port.type = PORT_UNKNOWN;
887 uart->port.dev = &serial8250_isa_devs->dev;
888 uart->port.port_id = line;
889 uart->capabilities = 0;
890 serial8250_init_port(uart);
891 serial8250_apply_quirks(uart);
892 uart_add_one_port(&serial8250_reg, &uart->port);
893 } else {
894 uart->port.dev = NULL;
895 }
896 mutex_unlock(&serial_mutex);
897 }
898 EXPORT_SYMBOL(serial8250_unregister_port);
899
900 MODULE_LICENSE("GPL");
901 MODULE_DESCRIPTION("Generic 8250/16x50 serial driver");
902