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/hashtable.h>
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/pm_runtime.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/string_helpers.h>
35#include <linux/uaccess.h>
36#include <linux/io.h>
37
38#include <asm/irq.h>
39
40#include "8250.h"
41
42#define PASS_LIMIT 512
43
44struct irq_info {
45 struct hlist_node node;
46 int irq;
47 spinlock_t lock; /* Protects list not the hash */
48 struct list_head *head;
49};
50
51#define IRQ_HASH_BITS 5 /* Can be adjusted later */
52static DEFINE_HASHTABLE(irq_lists, IRQ_HASH_BITS);
53static DEFINE_MUTEX(hash_mutex); /* Used to walk the hash */
54
55/*
56 * This is the serial driver's interrupt routine.
57 *
58 * Arjan thinks the old way was overly complex, so it got simplified.
59 * Alan disagrees, saying that need the complexity to handle the weird
60 * nature of ISA shared interrupts. (This is a special exception.)
61 *
62 * In order to handle ISA shared interrupts properly, we need to check
63 * that all ports have been serviced, and therefore the ISA interrupt
64 * line has been de-asserted.
65 *
66 * This means we need to loop through all ports. checking that they
67 * don't have an interrupt pending.
68 */
69static irqreturn_t serial8250_interrupt(int irq, void *dev_id)
70{
71 struct irq_info *i = dev_id;
72 struct list_head *l, *end = NULL;
73 int pass_counter = 0, handled = 0;
74
75 guard(spinlock)(l: &i->lock);
76
77 l = i->head;
78 do {
79 struct uart_8250_port *up = list_entry(l, struct uart_8250_port, list);
80 struct uart_port *port = &up->port;
81
82 if (port->handle_irq(port)) {
83 handled = 1;
84 end = NULL;
85 } else if (end == NULL)
86 end = l;
87
88 l = l->next;
89
90 if (l == i->head && pass_counter++ > PASS_LIMIT)
91 break;
92 } while (l != end);
93
94 return IRQ_RETVAL(handled);
95}
96
97/*
98 * To support ISA shared interrupts, we need to have one interrupt
99 * handler that ensures that the IRQ line has been deasserted
100 * before returning. Failing to do this will result in the IRQ
101 * line being stuck active, and, since ISA irqs are edge triggered,
102 * no more IRQs will be seen.
103 */
104static void serial_do_unlink(struct irq_info *i, struct uart_8250_port *up)
105{
106 spin_lock_irq(lock: &i->lock);
107
108 if (!list_empty(head: i->head)) {
109 if (i->head == &up->list)
110 i->head = i->head->next;
111 list_del(entry: &up->list);
112 } else {
113 BUG_ON(i->head != &up->list);
114 i->head = NULL;
115 }
116 spin_unlock_irq(lock: &i->lock);
117 /* List empty so throw away the hash node */
118 if (i->head == NULL) {
119 hlist_del(n: &i->node);
120 kfree(objp: i);
121 }
122}
123
124/*
125 * Either:
126 * - find the corresponding info in the hashtable and return it, or
127 * - allocate a new one, add it to the hashtable and return it.
128 */
129static struct irq_info *serial_get_or_create_irq_info(const struct uart_8250_port *up)
130{
131 struct irq_info *i;
132
133 guard(mutex)(T: &hash_mutex);
134
135 hash_for_each_possible(irq_lists, i, node, up->port.irq)
136 if (i->irq == up->port.irq)
137 return i;
138
139 i = kzalloc(sizeof(*i), GFP_KERNEL);
140 if (i == NULL)
141 return ERR_PTR(error: -ENOMEM);
142
143 spin_lock_init(&i->lock);
144 i->irq = up->port.irq;
145 hash_add(irq_lists, &i->node, i->irq);
146
147 return i;
148}
149
150static int serial_link_irq_chain(struct uart_8250_port *up)
151{
152 struct irq_info *i;
153 int ret;
154
155 i = serial_get_or_create_irq_info(up);
156 if (IS_ERR(ptr: i))
157 return PTR_ERR(ptr: i);
158
159 scoped_guard(spinlock_irq, &i->lock) {
160 if (i->head) {
161 list_add(new: &up->list, head: i->head);
162
163 return 0;
164 }
165
166 INIT_LIST_HEAD(list: &up->list);
167 i->head = &up->list;
168 }
169
170 ret = request_irq(irq: up->port.irq, handler: serial8250_interrupt, flags: up->port.irqflags, name: up->port.name, dev: i);
171 if (ret < 0)
172 serial_do_unlink(i, up);
173
174 return ret;
175}
176
177static void serial_unlink_irq_chain(struct uart_8250_port *up)
178{
179 struct irq_info *i;
180
181 guard(mutex)(T: &hash_mutex);
182
183 hash_for_each_possible(irq_lists, i, node, up->port.irq)
184 if (i->irq == up->port.irq) {
185 if (WARN_ON(i->head == NULL))
186 return;
187
188 if (list_empty(head: i->head))
189 free_irq(up->port.irq, i);
190
191 serial_do_unlink(i, up);
192
193 return;
194 }
195
196 WARN_ON(1);
197}
198
199/*
200 * This function is used to handle ports that do not have an
201 * interrupt. This doesn't work very well for 16450's, but gives
202 * barely passable results for a 16550A. (Although at the expense
203 * of much CPU overhead).
204 */
205static void serial8250_timeout(struct timer_list *t)
206{
207 struct uart_8250_port *up = timer_container_of(up, t, timer);
208
209 up->port.handle_irq(&up->port);
210 mod_timer(timer: &up->timer, expires: jiffies + uart_poll_timeout(port: &up->port));
211}
212
213static void serial8250_backup_timeout(struct timer_list *t)
214{
215 struct uart_8250_port *up = timer_container_of(up, t, timer);
216 unsigned int iir, ier = 0, lsr;
217 unsigned long flags;
218
219 uart_port_lock_irqsave(up: &up->port, flags: &flags);
220
221 /*
222 * Must disable interrupts or else we risk racing with the interrupt
223 * based handler.
224 */
225 if (up->port.irq) {
226 ier = serial_in(up, UART_IER);
227 serial_out(up, UART_IER, value: 0);
228 }
229
230 iir = serial_in(up, UART_IIR);
231
232 /*
233 * This should be a safe test for anyone who doesn't trust the
234 * IIR bits on their UART, but it's specifically designed for
235 * the "Diva" UART used on the management processor on many HP
236 * ia64 and parisc boxes.
237 */
238 lsr = serial_lsr_in(up);
239 if ((iir & UART_IIR_NO_INT) && (up->ier & UART_IER_THRI) &&
240 (!kfifo_is_empty(&up->port.state->port.xmit_fifo) ||
241 up->port.x_char) &&
242 (lsr & UART_LSR_THRE)) {
243 iir &= ~(UART_IIR_ID | UART_IIR_NO_INT);
244 iir |= UART_IIR_THRI;
245 }
246
247 if (!(iir & UART_IIR_NO_INT))
248 serial8250_tx_chars(up);
249
250 if (up->port.irq)
251 serial_out(up, UART_IER, value: ier);
252
253 uart_port_unlock_irqrestore(up: &up->port, flags);
254
255 /* Standard timer interval plus 0.2s to keep the port running */
256 mod_timer(timer: &up->timer,
257 expires: jiffies + uart_poll_timeout(port: &up->port) + HZ / 5);
258}
259
260static void univ8250_setup_timer(struct uart_8250_port *up)
261{
262 struct uart_port *port = &up->port;
263
264 /*
265 * The above check will only give an accurate result the first time
266 * the port is opened so this value needs to be preserved.
267 */
268 if (up->bugs & UART_BUG_THRE) {
269 pr_debug("%s - using backup timer\n", port->name);
270
271 up->timer.function = serial8250_backup_timeout;
272 mod_timer(timer: &up->timer, expires: jiffies +
273 uart_poll_timeout(port) + HZ / 5);
274 }
275
276 /*
277 * If the "interrupt" for this port doesn't correspond with any
278 * hardware interrupt, we use a timer-based system. The original
279 * driver used to do this with IRQ0.
280 */
281 if (!port->irq)
282 mod_timer(timer: &up->timer, expires: jiffies + uart_poll_timeout(port));
283}
284
285static int univ8250_setup_irq(struct uart_8250_port *up)
286{
287 struct uart_port *port = &up->port;
288
289 if (port->irq)
290 return serial_link_irq_chain(up);
291
292 return 0;
293}
294
295static void univ8250_release_irq(struct uart_8250_port *up)
296{
297 struct uart_port *port = &up->port;
298
299 timer_delete_sync(timer: &up->timer);
300 up->timer.function = serial8250_timeout;
301 if (port->irq)
302 serial_unlink_irq_chain(up);
303}
304
305const struct uart_ops *univ8250_port_base_ops;
306struct uart_ops univ8250_port_ops;
307
308static const struct uart_8250_ops univ8250_driver_ops = {
309 .setup_irq = univ8250_setup_irq,
310 .release_irq = univ8250_release_irq,
311 .setup_timer = univ8250_setup_timer,
312};
313
314static struct uart_8250_port serial8250_ports[UART_NR];
315
316/**
317 * serial8250_get_port - retrieve struct uart_8250_port
318 * @line: serial line number
319 *
320 * This function retrieves struct uart_8250_port for the specific line.
321 * This struct *must* *not* be used to perform a 8250 or serial core operation
322 * which is not accessible otherwise. Its only purpose is to make the struct
323 * accessible to the runtime-pm callbacks for context suspend/restore.
324 * The lock assumption made here is none because runtime-pm suspend/resume
325 * callbacks should not be invoked if there is any operation performed on the
326 * port.
327 */
328struct uart_8250_port *serial8250_get_port(int line)
329{
330 return &serial8250_ports[line];
331}
332EXPORT_SYMBOL_GPL(serial8250_get_port);
333
334static inline void serial8250_apply_quirks(struct uart_8250_port *up)
335{
336 up->port.quirks |= skip_txen_test ? UPQ_NO_TXEN_TEST : 0;
337}
338
339struct uart_8250_port *serial8250_setup_port(int index)
340{
341 struct uart_8250_port *up;
342
343 if (index >= UART_NR)
344 return NULL;
345
346 up = &serial8250_ports[index];
347 up->port.line = index;
348 up->port.port_id = index;
349
350 serial8250_init_port(up);
351 if (!univ8250_port_base_ops)
352 univ8250_port_base_ops = up->port.ops;
353 up->port.ops = &univ8250_port_ops;
354
355 timer_setup(&up->timer, serial8250_timeout, 0);
356
357 up->ops = &univ8250_driver_ops;
358
359 serial8250_set_defaults(up);
360
361 return up;
362}
363
364void __init serial8250_register_ports(struct uart_driver *drv, struct device *dev)
365{
366 int i;
367
368 for (i = 0; i < nr_uarts; i++) {
369 struct uart_8250_port *up = &serial8250_ports[i];
370
371 if (up->port.type == PORT_8250_CIR)
372 continue;
373
374 if (up->port.dev)
375 continue;
376
377 up->port.dev = dev;
378
379 if (uart_console_registered(port: &up->port))
380 pm_runtime_get_sync(dev: up->port.dev);
381
382 serial8250_apply_quirks(up);
383 uart_add_one_port(reg: drv, port: &up->port);
384 }
385}
386
387#ifdef CONFIG_SERIAL_8250_CONSOLE
388
389static void univ8250_console_write(struct console *co, const char *s,
390 unsigned int count)
391{
392 struct uart_8250_port *up = &serial8250_ports[co->index];
393
394 serial8250_console_write(up, s, count);
395}
396
397static int univ8250_console_setup(struct console *co, char *options)
398{
399 struct uart_8250_port *up;
400 struct uart_port *port;
401 int retval, i;
402
403 /*
404 * Check whether an invalid uart number has been specified, and
405 * if so, search for the first available port that does have
406 * console support.
407 */
408 if (co->index < 0 || co->index >= UART_NR)
409 co->index = 0;
410
411 /*
412 * If the console is past the initial isa ports, init more ports up to
413 * co->index as needed and increment nr_uarts accordingly.
414 */
415 for (i = nr_uarts; i <= co->index; i++) {
416 up = serial8250_setup_port(index: i);
417 if (!up)
418 return -ENODEV;
419 nr_uarts++;
420 }
421
422 port = &serial8250_ports[co->index].port;
423 /* link port to console */
424 uart_port_set_cons(up: port, con: co);
425
426 retval = serial8250_console_setup(port, options, probe: false);
427 if (retval != 0)
428 uart_port_set_cons(up: port, NULL);
429 return retval;
430}
431
432static int univ8250_console_exit(struct console *co)
433{
434 struct uart_port *port;
435
436 port = &serial8250_ports[co->index].port;
437 return serial8250_console_exit(port);
438}
439
440/**
441 * univ8250_console_match - non-standard console matching
442 * @co: registering console
443 * @name: name from console command line
444 * @idx: index from console command line
445 * @options: ptr to option string from console command line
446 *
447 * Only attempts to match console command lines of the form:
448 * console=uart[8250],io|mmio|mmio16|mmio32,<addr>[,<options>]
449 * console=uart[8250],0x<addr>[,<options>]
450 * This form is used to register an initial earlycon boot console and
451 * replace it with the serial8250_console at 8250 driver init.
452 *
453 * Performs console setup for a match (as required by interface)
454 * If no <options> are specified, then assume the h/w is already setup.
455 *
456 * Returns 0 if console matches; otherwise non-zero to use default matching
457 */
458static int univ8250_console_match(struct console *co, char *name, int idx,
459 char *options)
460{
461 char match[] = "uart"; /* 8250-specific earlycon name */
462 enum uart_iotype iotype;
463 resource_size_t addr;
464 int i;
465
466 if (strncmp(name, match, 4) != 0)
467 return -ENODEV;
468
469 if (uart_parse_earlycon(p: options, iotype: &iotype, addr: &addr, options: &options))
470 return -ENODEV;
471
472 /* try to match the port specified on the command line */
473 for (i = 0; i < nr_uarts; i++) {
474 struct uart_port *port = &serial8250_ports[i].port;
475
476 if (port->iotype != iotype)
477 continue;
478 if ((iotype == UPIO_MEM || iotype == UPIO_MEM16 ||
479 iotype == UPIO_MEM32 || iotype == UPIO_MEM32BE)
480 && (port->mapbase != addr))
481 continue;
482 if (iotype == UPIO_PORT && port->iobase != addr)
483 continue;
484
485 co->index = i;
486 uart_port_set_cons(up: port, con: co);
487 return serial8250_console_setup(port, options, probe: true);
488 }
489
490 return -ENODEV;
491}
492
493static struct console univ8250_console = {
494 .name = "ttyS",
495 .write = univ8250_console_write,
496 .device = uart_console_device,
497 .setup = univ8250_console_setup,
498 .exit = univ8250_console_exit,
499 .match = univ8250_console_match,
500 .flags = CON_PRINTBUFFER | CON_ANYTIME,
501 .index = -1,
502 .data = &serial8250_reg,
503};
504
505static int __init univ8250_console_init(void)
506{
507 if (nr_uarts == 0)
508 return -ENODEV;
509
510 serial8250_isa_init_ports();
511 register_console(&univ8250_console);
512 return 0;
513}
514console_initcall(univ8250_console_init);
515
516#define SERIAL8250_CONSOLE (&univ8250_console)
517#else
518#define SERIAL8250_CONSOLE NULL
519#endif
520
521struct uart_driver serial8250_reg = {
522 .owner = THIS_MODULE,
523 .driver_name = "serial",
524 .dev_name = "ttyS",
525 .major = TTY_MAJOR,
526 .minor = 64,
527 .cons = SERIAL8250_CONSOLE,
528};
529
530/*
531 * early_serial_setup - early registration for 8250 ports
532 *
533 * Setup an 8250 port structure prior to console initialisation. Use
534 * after console initialisation will cause undefined behaviour.
535 */
536int __init early_serial_setup(struct uart_port *port)
537{
538 struct uart_port *p;
539
540 if (port->line >= ARRAY_SIZE(serial8250_ports) || nr_uarts == 0)
541 return -ENODEV;
542
543 serial8250_isa_init_ports();
544 p = &serial8250_ports[port->line].port;
545 p->iobase = port->iobase;
546 p->membase = port->membase;
547 p->irq = port->irq;
548 p->irqflags = port->irqflags;
549 p->uartclk = port->uartclk;
550 p->fifosize = port->fifosize;
551 p->regshift = port->regshift;
552 p->iotype = port->iotype;
553 p->flags = port->flags;
554 p->mapbase = port->mapbase;
555 p->mapsize = port->mapsize;
556 p->private_data = port->private_data;
557 p->type = port->type;
558 p->line = port->line;
559
560 serial8250_set_defaults(up: up_to_u8250p(up: p));
561
562 if (port->serial_in)
563 p->serial_in = port->serial_in;
564 if (port->serial_out)
565 p->serial_out = port->serial_out;
566 if (port->handle_irq)
567 p->handle_irq = port->handle_irq;
568
569 return 0;
570}
571
572/**
573 * serial8250_suspend_port - suspend one serial port
574 * @line: serial line number
575 *
576 * Suspend one serial port.
577 */
578void serial8250_suspend_port(int line)
579{
580 struct uart_8250_port *up = &serial8250_ports[line];
581 struct uart_port *port = &up->port;
582
583 if (!console_suspend_enabled && uart_console(port) &&
584 port->type != PORT_8250) {
585 unsigned char canary = 0xa5;
586
587 serial_out(up, UART_SCR, value: canary);
588 if (serial_in(up, UART_SCR) == canary)
589 up->canary = canary;
590 }
591
592 uart_suspend_port(reg: &serial8250_reg, port);
593}
594EXPORT_SYMBOL(serial8250_suspend_port);
595
596/**
597 * serial8250_resume_port - resume one serial port
598 * @line: serial line number
599 *
600 * Resume one serial port.
601 */
602void serial8250_resume_port(int line)
603{
604 struct uart_8250_port *up = &serial8250_ports[line];
605 struct uart_port *port = &up->port;
606
607 up->canary = 0;
608
609 if (up->capabilities & UART_NATSEMI) {
610 /* Ensure it's still in high speed mode */
611 serial_port_out(up: port, UART_LCR, value: 0xE0);
612
613 ns16550a_goto_highspeed(up);
614
615 serial_port_out(up: port, UART_LCR, value: 0);
616 port->uartclk = 921600*16;
617 }
618 uart_resume_port(reg: &serial8250_reg, port);
619}
620EXPORT_SYMBOL(serial8250_resume_port);
621
622/*
623 * serial8250_register_8250_port and serial8250_unregister_port allows for
624 * 16x50 serial ports to be configured at run-time, to support PCMCIA
625 * modems and PCI multiport cards.
626 */
627static DEFINE_MUTEX(serial_mutex);
628
629static struct uart_8250_port *serial8250_find_match_or_unused(const struct uart_port *port)
630{
631 int i;
632
633 /*
634 * First, find a port entry which matches.
635 */
636 for (i = 0; i < nr_uarts; i++)
637 if (uart_match_port(port1: &serial8250_ports[i].port, port2: port))
638 return &serial8250_ports[i];
639
640 /* try line number first if still available */
641 i = port->line;
642 if (i < nr_uarts && serial8250_ports[i].port.type == PORT_UNKNOWN &&
643 serial8250_ports[i].port.iobase == 0)
644 return &serial8250_ports[i];
645 /*
646 * We didn't find a matching entry, so look for the first
647 * free entry. We look for one which hasn't been previously
648 * used (indicated by zero iobase).
649 */
650 for (i = 0; i < nr_uarts; i++)
651 if (serial8250_ports[i].port.type == PORT_UNKNOWN &&
652 serial8250_ports[i].port.iobase == 0)
653 return &serial8250_ports[i];
654
655 /*
656 * That also failed. Last resort is to find any entry which
657 * doesn't have a real port associated with it.
658 */
659 for (i = 0; i < nr_uarts; i++)
660 if (serial8250_ports[i].port.type == PORT_UNKNOWN)
661 return &serial8250_ports[i];
662
663 return NULL;
664}
665
666static void serial_8250_overrun_backoff_work(struct work_struct *work)
667{
668 struct uart_8250_port *up = container_of(to_delayed_work(work), struct uart_8250_port,
669 overrun_backoff);
670
671 guard(uart_port_lock_irqsave)(l: &up->port);
672 up->ier |= UART_IER_RLSI | UART_IER_RDI;
673 serial_out(up, UART_IER, value: up->ier);
674}
675
676/**
677 * serial8250_register_8250_port - register a serial port
678 * @up: serial port template
679 *
680 * Configure the serial port specified by the request. If the
681 * port exists and is in use, it is hung up and unregistered
682 * first.
683 *
684 * The port is then probed and if necessary the IRQ is autodetected
685 * If this fails an error is returned.
686 *
687 * On success the port is ready to use and the line number is returned.
688 */
689int serial8250_register_8250_port(const struct uart_8250_port *up)
690{
691 struct uart_8250_port *uart;
692 int ret;
693
694 if (up->port.uartclk == 0)
695 return -EINVAL;
696
697 guard(mutex)(T: &serial_mutex);
698
699 uart = serial8250_find_match_or_unused(port: &up->port);
700 if (!uart) {
701 /*
702 * If the port is past the initial isa ports, initialize a new
703 * port and increment nr_uarts accordingly.
704 */
705 uart = serial8250_setup_port(index: nr_uarts);
706 if (!uart)
707 return -ENOSPC;
708 nr_uarts++;
709 }
710
711 /* Check if it is CIR already. We check this below again, see there why. */
712 if (uart->port.type == PORT_8250_CIR)
713 return -ENODEV;
714
715 if (uart->port.dev)
716 uart_remove_one_port(reg: &serial8250_reg, port: &uart->port);
717
718 uart->port.ctrl_id = up->port.ctrl_id;
719 uart->port.port_id = up->port.port_id;
720 uart->port.iobase = up->port.iobase;
721 uart->port.membase = up->port.membase;
722 uart->port.irq = up->port.irq;
723 uart->port.irqflags = up->port.irqflags;
724 uart->port.uartclk = up->port.uartclk;
725 uart->port.fifosize = up->port.fifosize;
726 uart->port.regshift = up->port.regshift;
727 uart->port.iotype = up->port.iotype;
728 uart->port.flags = up->port.flags | UPF_BOOT_AUTOCONF;
729 uart->bugs = up->bugs;
730 uart->port.mapbase = up->port.mapbase;
731 uart->port.mapsize = up->port.mapsize;
732 uart->port.private_data = up->port.private_data;
733 uart->tx_loadsz = up->tx_loadsz;
734 uart->capabilities = up->capabilities;
735 uart->port.throttle = up->port.throttle;
736 uart->port.unthrottle = up->port.unthrottle;
737 uart->port.rs485_config = up->port.rs485_config;
738 uart->port.rs485_supported = up->port.rs485_supported;
739 uart->port.rs485 = up->port.rs485;
740 uart->rs485_start_tx = up->rs485_start_tx;
741 uart->rs485_stop_tx = up->rs485_stop_tx;
742 uart->lsr_save_mask = up->lsr_save_mask;
743 uart->dma = up->dma;
744
745 /* Take tx_loadsz from fifosize if it wasn't set separately */
746 if (uart->port.fifosize && !uart->tx_loadsz)
747 uart->tx_loadsz = uart->port.fifosize;
748
749 if (up->port.dev) {
750 uart->port.dev = up->port.dev;
751 ret = uart_get_rs485_mode(port: &uart->port);
752 if (ret)
753 goto err;
754 }
755
756 if (up->port.flags & UPF_FIXED_TYPE)
757 uart->port.type = up->port.type;
758
759 /*
760 * Only call mctrl_gpio_init(), if the device has no ACPI
761 * companion device
762 */
763 if (!has_acpi_companion(dev: uart->port.dev)) {
764 struct mctrl_gpios *gpios = mctrl_gpio_init(port: &uart->port, idx: 0);
765 if (IS_ERR(ptr: gpios)) {
766 ret = PTR_ERR(ptr: gpios);
767 goto err;
768 } else {
769 uart->gpios = gpios;
770 }
771 }
772
773 serial8250_set_defaults(up: uart);
774
775 /* Possibly override default I/O functions. */
776 if (up->port.serial_in)
777 uart->port.serial_in = up->port.serial_in;
778 if (up->port.serial_out)
779 uart->port.serial_out = up->port.serial_out;
780 if (up->port.handle_irq)
781 uart->port.handle_irq = up->port.handle_irq;
782 /* Possibly override set_termios call */
783 if (up->port.set_termios)
784 uart->port.set_termios = up->port.set_termios;
785 if (up->port.set_ldisc)
786 uart->port.set_ldisc = up->port.set_ldisc;
787 if (up->port.get_mctrl)
788 uart->port.get_mctrl = up->port.get_mctrl;
789 if (up->port.set_mctrl)
790 uart->port.set_mctrl = up->port.set_mctrl;
791 if (up->port.get_divisor)
792 uart->port.get_divisor = up->port.get_divisor;
793 if (up->port.set_divisor)
794 uart->port.set_divisor = up->port.set_divisor;
795 if (up->port.startup)
796 uart->port.startup = up->port.startup;
797 if (up->port.shutdown)
798 uart->port.shutdown = up->port.shutdown;
799 if (up->port.pm)
800 uart->port.pm = up->port.pm;
801 if (up->port.handle_break)
802 uart->port.handle_break = up->port.handle_break;
803 if (up->dl_read)
804 uart->dl_read = up->dl_read;
805 if (up->dl_write)
806 uart->dl_write = up->dl_write;
807
808 /* Check the type (again)! It might have changed by the port.type assignment above. */
809 if (uart->port.type != PORT_8250_CIR) {
810 if (uart_console_registered(port: &uart->port))
811 pm_runtime_get_sync(dev: uart->port.dev);
812
813 if (serial8250_isa_config != NULL)
814 serial8250_isa_config(0, &uart->port,
815 &uart->capabilities);
816
817 serial8250_apply_quirks(up: uart);
818 ret = uart_add_one_port(reg: &serial8250_reg,
819 port: &uart->port);
820 if (ret)
821 goto err;
822
823 ret = uart->port.line;
824 } else {
825 dev_info(uart->port.dev,
826 "skipping CIR port at 0x%lx / 0x%llx, IRQ %d\n",
827 uart->port.iobase,
828 (unsigned long long)uart->port.mapbase,
829 uart->port.irq);
830
831 ret = 0;
832 }
833
834 if (!uart->lsr_save_mask)
835 uart->lsr_save_mask = LSR_SAVE_FLAGS; /* Use default LSR mask */
836
837 /* Initialise interrupt backoff work if required */
838 if (up->overrun_backoff_time_ms > 0) {
839 uart->overrun_backoff_time_ms =
840 up->overrun_backoff_time_ms;
841 INIT_DELAYED_WORK(&uart->overrun_backoff,
842 serial_8250_overrun_backoff_work);
843 } else {
844 uart->overrun_backoff_time_ms = 0;
845 }
846
847 return ret;
848
849err:
850 uart->port.dev = NULL;
851 return ret;
852}
853EXPORT_SYMBOL(serial8250_register_8250_port);
854
855/**
856 * serial8250_unregister_port - remove a 16x50 serial port at runtime
857 * @line: serial line number
858 *
859 * Remove one serial port. This may not be called from interrupt
860 * context. We hand the port back to the our control.
861 */
862void serial8250_unregister_port(int line)
863{
864 struct uart_8250_port *uart = &serial8250_ports[line];
865
866 guard(mutex)(T: &serial_mutex);
867
868 if (uart->em485) {
869 guard(uart_port_lock_irqsave)(l: &uart->port);
870 serial8250_em485_destroy(p: uart);
871 }
872
873 uart_remove_one_port(reg: &serial8250_reg, port: &uart->port);
874 if (serial8250_isa_devs) {
875 uart->port.flags &= ~UPF_BOOT_AUTOCONF;
876 uart->port.type = PORT_UNKNOWN;
877 uart->port.dev = &serial8250_isa_devs->dev;
878 uart->port.port_id = line;
879 uart->capabilities = 0;
880 serial8250_init_port(up: uart);
881 serial8250_apply_quirks(up: uart);
882 uart_add_one_port(reg: &serial8250_reg, port: &uart->port);
883 } else {
884 uart->port.dev = NULL;
885 }
886}
887EXPORT_SYMBOL(serial8250_unregister_port);
888
889MODULE_LICENSE("GPL");
890MODULE_DESCRIPTION("Generic 8250/16x50 serial driver");
891