Line data Source code
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 :
44 : struct 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 */
52 : static DEFINE_HASHTABLE(irq_lists, IRQ_HASH_BITS);
53 : static 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 : */
69 0 : static irqreturn_t serial8250_interrupt(int irq, void *dev_id)
70 : {
71 0 : struct irq_info *i = dev_id;
72 0 : struct list_head *l, *end = NULL;
73 0 : int pass_counter = 0, handled = 0;
74 :
75 0 : spin_lock(&i->lock);
76 :
77 0 : l = i->head;
78 0 : do {
79 0 : struct uart_8250_port *up = list_entry(l, struct uart_8250_port, list);
80 0 : struct uart_port *port = &up->port;
81 :
82 0 : if (port->handle_irq(port)) {
83 0 : handled = 1;
84 0 : end = NULL;
85 0 : } else if (end == NULL)
86 0 : end = l;
87 :
88 0 : l = l->next;
89 :
90 0 : if (l == i->head && pass_counter++ > PASS_LIMIT)
91 0 : break;
92 0 : } while (l != end);
93 :
94 0 : spin_unlock(&i->lock);
95 :
96 0 : return IRQ_RETVAL(handled);
97 0 : }
98 :
99 : /*
100 : * To support ISA shared interrupts, we need to have one interrupt
101 : * handler that ensures that the IRQ line has been deasserted
102 : * before returning. Failing to do this will result in the IRQ
103 : * line being stuck active, and, since ISA irqs are edge triggered,
104 : * no more IRQs will be seen.
105 : */
106 0 : static void serial_do_unlink(struct irq_info *i, struct uart_8250_port *up)
107 : {
108 0 : spin_lock_irq(&i->lock);
109 :
110 0 : if (!list_empty(i->head)) {
111 0 : if (i->head == &up->list)
112 0 : i->head = i->head->next;
113 0 : list_del(&up->list);
114 0 : } else {
115 0 : BUG_ON(i->head != &up->list);
116 0 : i->head = NULL;
117 : }
118 0 : spin_unlock_irq(&i->lock);
119 : /* List empty so throw away the hash node */
120 0 : if (i->head == NULL) {
121 0 : hlist_del(&i->node);
122 0 : kfree(i);
123 0 : }
124 0 : }
125 :
126 : /*
127 : * Either:
128 : * - find the corresponding info in the hashtable and return it, or
129 : * - allocate a new one, add it to the hashtable and return it.
130 : */
131 0 : static struct irq_info *serial_get_or_create_irq_info(const struct uart_8250_port *up)
132 : {
133 0 : struct irq_info *i;
134 :
135 0 : mutex_lock(&hash_mutex);
136 :
137 0 : hash_for_each_possible(irq_lists, i, node, up->port.irq)
138 0 : if (i->irq == up->port.irq)
139 0 : goto unlock;
140 :
141 0 : i = kzalloc(sizeof(*i), GFP_KERNEL);
142 0 : if (i == NULL) {
143 0 : i = ERR_PTR(-ENOMEM);
144 0 : goto unlock;
145 : }
146 0 : spin_lock_init(&i->lock);
147 0 : i->irq = up->port.irq;
148 0 : hash_add(irq_lists, &i->node, i->irq);
149 : unlock:
150 0 : mutex_unlock(&hash_mutex);
151 :
152 0 : return i;
153 0 : }
154 :
155 0 : static int serial_link_irq_chain(struct uart_8250_port *up)
156 : {
157 0 : struct irq_info *i;
158 0 : int ret;
159 :
160 0 : i = serial_get_or_create_irq_info(up);
161 0 : if (IS_ERR(i))
162 0 : return PTR_ERR(i);
163 :
164 0 : spin_lock_irq(&i->lock);
165 :
166 0 : if (i->head) {
167 0 : list_add(&up->list, i->head);
168 0 : spin_unlock_irq(&i->lock);
169 :
170 0 : ret = 0;
171 0 : } else {
172 0 : INIT_LIST_HEAD(&up->list);
173 0 : i->head = &up->list;
174 0 : spin_unlock_irq(&i->lock);
175 0 : ret = request_irq(up->port.irq, serial8250_interrupt,
176 0 : up->port.irqflags, up->port.name, i);
177 0 : if (ret < 0)
178 0 : serial_do_unlink(i, up);
179 : }
180 :
181 0 : return ret;
182 0 : }
183 :
184 0 : static void serial_unlink_irq_chain(struct uart_8250_port *up)
185 : {
186 0 : struct irq_info *i;
187 :
188 0 : mutex_lock(&hash_mutex);
189 :
190 0 : hash_for_each_possible(irq_lists, i, node, up->port.irq)
191 0 : if (i->irq == up->port.irq)
192 0 : break;
193 :
194 0 : BUG_ON(i == NULL);
195 0 : BUG_ON(i->head == NULL);
196 :
197 0 : if (list_empty(i->head))
198 0 : free_irq(up->port.irq, i);
199 :
200 0 : serial_do_unlink(i, up);
201 0 : mutex_unlock(&hash_mutex);
202 0 : }
203 :
204 : /*
205 : * This function is used to handle ports that do not have an
206 : * interrupt. This doesn't work very well for 16450's, but gives
207 : * barely passable results for a 16550A. (Although at the expense
208 : * of much CPU overhead).
209 : */
210 0 : static void serial8250_timeout(struct timer_list *t)
211 : {
212 0 : struct uart_8250_port *up = timer_container_of(up, t, timer);
213 :
214 0 : up->port.handle_irq(&up->port);
215 0 : mod_timer(&up->timer, jiffies + uart_poll_timeout(&up->port));
216 0 : }
217 :
218 0 : static void serial8250_backup_timeout(struct timer_list *t)
219 : {
220 0 : struct uart_8250_port *up = timer_container_of(up, t, timer);
221 0 : unsigned int iir, ier = 0, lsr;
222 0 : unsigned long flags;
223 :
224 0 : uart_port_lock_irqsave(&up->port, &flags);
225 :
226 : /*
227 : * Must disable interrupts or else we risk racing with the interrupt
228 : * based handler.
229 : */
230 0 : if (up->port.irq) {
231 0 : ier = serial_in(up, UART_IER);
232 0 : serial_out(up, UART_IER, 0);
233 0 : }
234 :
235 0 : iir = serial_in(up, UART_IIR);
236 :
237 : /*
238 : * This should be a safe test for anyone who doesn't trust the
239 : * IIR bits on their UART, but it's specifically designed for
240 : * the "Diva" UART used on the management processor on many HP
241 : * ia64 and parisc boxes.
242 : */
243 0 : lsr = serial_lsr_in(up);
244 0 : if ((iir & UART_IIR_NO_INT) && (up->ier & UART_IER_THRI) &&
245 0 : (!kfifo_is_empty(&up->port.state->port.xmit_fifo) ||
246 0 : up->port.x_char) &&
247 0 : (lsr & UART_LSR_THRE)) {
248 0 : iir &= ~(UART_IIR_ID | UART_IIR_NO_INT);
249 0 : iir |= UART_IIR_THRI;
250 0 : }
251 :
252 0 : if (!(iir & UART_IIR_NO_INT))
253 0 : serial8250_tx_chars(up);
254 :
255 0 : if (up->port.irq)
256 0 : serial_out(up, UART_IER, ier);
257 :
258 0 : uart_port_unlock_irqrestore(&up->port, flags);
259 :
260 : /* Standard timer interval plus 0.2s to keep the port running */
261 0 : mod_timer(&up->timer,
262 0 : jiffies + uart_poll_timeout(&up->port) + HZ / 5);
263 0 : }
264 :
265 0 : static void univ8250_setup_timer(struct uart_8250_port *up)
266 : {
267 0 : struct uart_port *port = &up->port;
268 :
269 : /*
270 : * The above check will only give an accurate result the first time
271 : * the port is opened so this value needs to be preserved.
272 : */
273 0 : if (up->bugs & UART_BUG_THRE) {
274 0 : pr_debug("%s - using backup timer\n", port->name);
275 :
276 0 : up->timer.function = serial8250_backup_timeout;
277 0 : mod_timer(&up->timer, jiffies +
278 0 : uart_poll_timeout(port) + HZ / 5);
279 0 : }
280 :
281 : /*
282 : * If the "interrupt" for this port doesn't correspond with any
283 : * hardware interrupt, we use a timer-based system. The original
284 : * driver used to do this with IRQ0.
285 : */
286 0 : if (!port->irq)
287 0 : mod_timer(&up->timer, jiffies + uart_poll_timeout(port));
288 0 : }
289 :
290 0 : static int univ8250_setup_irq(struct uart_8250_port *up)
291 : {
292 0 : struct uart_port *port = &up->port;
293 :
294 0 : if (port->irq)
295 0 : return serial_link_irq_chain(up);
296 :
297 0 : return 0;
298 0 : }
299 :
300 0 : static void univ8250_release_irq(struct uart_8250_port *up)
301 : {
302 0 : struct uart_port *port = &up->port;
303 :
304 0 : timer_delete_sync(&up->timer);
305 0 : up->timer.function = serial8250_timeout;
306 0 : if (port->irq)
307 0 : serial_unlink_irq_chain(up);
308 0 : }
309 :
310 : const struct uart_ops *univ8250_port_base_ops = NULL;
311 : struct uart_ops univ8250_port_ops;
312 :
313 : static const struct uart_8250_ops univ8250_driver_ops = {
314 : .setup_irq = univ8250_setup_irq,
315 : .release_irq = univ8250_release_irq,
316 : .setup_timer = univ8250_setup_timer,
317 : };
318 :
319 : static struct uart_8250_port serial8250_ports[UART_NR];
320 :
321 : /**
322 : * serial8250_get_port - retrieve struct uart_8250_port
323 : * @line: serial line number
324 : *
325 : * This function retrieves struct uart_8250_port for the specific line.
326 : * This struct *must* *not* be used to perform a 8250 or serial core operation
327 : * which is not accessible otherwise. Its only purpose is to make the struct
328 : * accessible to the runtime-pm callbacks for context suspend/restore.
329 : * The lock assumption made here is none because runtime-pm suspend/resume
330 : * callbacks should not be invoked if there is any operation performed on the
331 : * port.
332 : */
333 0 : struct uart_8250_port *serial8250_get_port(int line)
334 : {
335 0 : return &serial8250_ports[line];
336 : }
337 : EXPORT_SYMBOL_GPL(serial8250_get_port);
338 :
339 0 : static inline void serial8250_apply_quirks(struct uart_8250_port *up)
340 : {
341 0 : up->port.quirks |= skip_txen_test ? UPQ_NO_TXEN_TEST : 0;
342 0 : }
343 :
344 0 : struct uart_8250_port *serial8250_setup_port(int index)
345 : {
346 0 : struct uart_8250_port *up;
347 :
348 0 : if (index >= UART_NR)
349 0 : return NULL;
350 :
351 0 : up = &serial8250_ports[index];
352 0 : up->port.line = index;
353 0 : up->port.port_id = index;
354 :
355 0 : serial8250_init_port(up);
356 0 : if (!univ8250_port_base_ops)
357 0 : univ8250_port_base_ops = up->port.ops;
358 0 : up->port.ops = &univ8250_port_ops;
359 :
360 0 : timer_setup(&up->timer, serial8250_timeout, 0);
361 :
362 0 : up->ops = &univ8250_driver_ops;
363 :
364 0 : serial8250_set_defaults(up);
365 :
366 0 : return up;
367 0 : }
368 :
369 0 : void __init serial8250_register_ports(struct uart_driver *drv, struct device *dev)
370 : {
371 0 : int i;
372 :
373 0 : for (i = 0; i < nr_uarts; i++) {
374 0 : struct uart_8250_port *up = &serial8250_ports[i];
375 :
376 0 : if (up->port.type == PORT_8250_CIR)
377 0 : continue;
378 :
379 0 : if (up->port.dev)
380 0 : continue;
381 :
382 0 : up->port.dev = dev;
383 :
384 0 : if (uart_console_registered(&up->port))
385 0 : pm_runtime_get_sync(up->port.dev);
386 :
387 0 : serial8250_apply_quirks(up);
388 0 : uart_add_one_port(drv, &up->port);
389 0 : }
390 0 : }
391 :
392 : #ifdef CONFIG_SERIAL_8250_CONSOLE
393 :
394 0 : static void univ8250_console_write(struct console *co, const char *s,
395 : unsigned int count)
396 : {
397 0 : struct uart_8250_port *up = &serial8250_ports[co->index];
398 :
399 0 : serial8250_console_write(up, s, count);
400 0 : }
401 :
402 0 : static int univ8250_console_setup(struct console *co, char *options)
403 : {
404 0 : struct uart_8250_port *up;
405 0 : struct uart_port *port;
406 0 : int retval, i;
407 :
408 : /*
409 : * Check whether an invalid uart number has been specified, and
410 : * if so, search for the first available port that does have
411 : * console support.
412 : */
413 0 : if (co->index < 0 || co->index >= UART_NR)
414 0 : co->index = 0;
415 :
416 : /*
417 : * If the console is past the initial isa ports, init more ports up to
418 : * co->index as needed and increment nr_uarts accordingly.
419 : */
420 0 : for (i = nr_uarts; i <= co->index; i++) {
421 0 : up = serial8250_setup_port(i);
422 0 : if (!up)
423 0 : return -ENODEV;
424 0 : nr_uarts++;
425 0 : }
426 :
427 0 : port = &serial8250_ports[co->index].port;
428 : /* link port to console */
429 0 : uart_port_set_cons(port, co);
430 :
431 0 : retval = serial8250_console_setup(port, options, false);
432 0 : if (retval != 0)
433 0 : uart_port_set_cons(port, NULL);
434 0 : return retval;
435 0 : }
436 :
437 0 : static int univ8250_console_exit(struct console *co)
438 : {
439 0 : struct uart_port *port;
440 :
441 0 : port = &serial8250_ports[co->index].port;
442 0 : return serial8250_console_exit(port);
443 0 : }
444 :
445 : /**
446 : * univ8250_console_match - non-standard console matching
447 : * @co: registering console
448 : * @name: name from console command line
449 : * @idx: index from console command line
450 : * @options: ptr to option string from console command line
451 : *
452 : * Only attempts to match console command lines of the form:
453 : * console=uart[8250],io|mmio|mmio16|mmio32,<addr>[,<options>]
454 : * console=uart[8250],0x<addr>[,<options>]
455 : * This form is used to register an initial earlycon boot console and
456 : * replace it with the serial8250_console at 8250 driver init.
457 : *
458 : * Performs console setup for a match (as required by interface)
459 : * If no <options> are specified, then assume the h/w is already setup.
460 : *
461 : * Returns 0 if console matches; otherwise non-zero to use default matching
462 : */
463 0 : static int univ8250_console_match(struct console *co, char *name, int idx,
464 : char *options)
465 : {
466 0 : char match[] = "uart"; /* 8250-specific earlycon name */
467 0 : enum uart_iotype iotype;
468 0 : resource_size_t addr;
469 0 : int i;
470 :
471 0 : if (strncmp(name, match, 4) != 0)
472 0 : return -ENODEV;
473 :
474 0 : if (uart_parse_earlycon(options, &iotype, &addr, &options))
475 0 : return -ENODEV;
476 :
477 : /* try to match the port specified on the command line */
478 0 : for (i = 0; i < nr_uarts; i++) {
479 0 : struct uart_port *port = &serial8250_ports[i].port;
480 :
481 0 : if (port->iotype != iotype)
482 0 : continue;
483 0 : if ((iotype == UPIO_MEM || iotype == UPIO_MEM16 ||
484 0 : iotype == UPIO_MEM32 || iotype == UPIO_MEM32BE)
485 0 : && (port->mapbase != addr))
486 0 : continue;
487 0 : if (iotype == UPIO_PORT && port->iobase != addr)
488 0 : continue;
489 :
490 0 : co->index = i;
491 0 : uart_port_set_cons(port, co);
492 0 : return serial8250_console_setup(port, options, true);
493 0 : }
494 :
495 0 : return -ENODEV;
496 0 : }
497 :
498 : static struct console univ8250_console = {
499 : .name = "ttyS",
500 : .write = univ8250_console_write,
501 : .device = uart_console_device,
502 : .setup = univ8250_console_setup,
503 : .exit = univ8250_console_exit,
504 : .match = univ8250_console_match,
505 : .flags = CON_PRINTBUFFER | CON_ANYTIME,
506 : .index = -1,
507 : .data = &serial8250_reg,
508 : };
509 :
510 0 : static int __init univ8250_console_init(void)
511 : {
512 0 : if (nr_uarts == 0)
513 0 : return -ENODEV;
514 :
515 0 : serial8250_isa_init_ports();
516 0 : register_console(&univ8250_console);
517 0 : return 0;
518 0 : }
519 : console_initcall(univ8250_console_init);
520 :
521 : #define SERIAL8250_CONSOLE (&univ8250_console)
522 : #else
523 : #define SERIAL8250_CONSOLE NULL
524 : #endif
525 :
526 : struct uart_driver serial8250_reg = {
527 : .owner = THIS_MODULE,
528 : .driver_name = "serial",
529 : .dev_name = "ttyS",
530 : .major = TTY_MAJOR,
531 : .minor = 64,
532 : .cons = SERIAL8250_CONSOLE,
533 : };
534 :
535 : /*
536 : * early_serial_setup - early registration for 8250 ports
537 : *
538 : * Setup an 8250 port structure prior to console initialisation. Use
539 : * after console initialisation will cause undefined behaviour.
540 : */
541 0 : int __init early_serial_setup(struct uart_port *port)
542 : {
543 0 : struct uart_port *p;
544 :
545 0 : if (port->line >= ARRAY_SIZE(serial8250_ports) || nr_uarts == 0)
546 0 : return -ENODEV;
547 :
548 0 : serial8250_isa_init_ports();
549 0 : p = &serial8250_ports[port->line].port;
550 0 : p->iobase = port->iobase;
551 0 : p->membase = port->membase;
552 0 : p->irq = port->irq;
553 0 : p->irqflags = port->irqflags;
554 0 : p->uartclk = port->uartclk;
555 0 : p->fifosize = port->fifosize;
556 0 : p->regshift = port->regshift;
557 0 : p->iotype = port->iotype;
558 0 : p->flags = port->flags;
559 0 : p->mapbase = port->mapbase;
560 0 : p->mapsize = port->mapsize;
561 0 : p->private_data = port->private_data;
562 0 : p->type = port->type;
563 0 : p->line = port->line;
564 :
565 0 : serial8250_set_defaults(up_to_u8250p(p));
566 :
567 0 : if (port->serial_in)
568 0 : p->serial_in = port->serial_in;
569 0 : if (port->serial_out)
570 0 : p->serial_out = port->serial_out;
571 0 : if (port->handle_irq)
572 0 : p->handle_irq = port->handle_irq;
573 :
574 0 : return 0;
575 0 : }
576 :
577 : /**
578 : * serial8250_suspend_port - suspend one serial port
579 : * @line: serial line number
580 : *
581 : * Suspend one serial port.
582 : */
583 0 : void serial8250_suspend_port(int line)
584 : {
585 0 : struct uart_8250_port *up = &serial8250_ports[line];
586 0 : struct uart_port *port = &up->port;
587 :
588 0 : if (!console_suspend_enabled && uart_console(port) &&
589 0 : port->type != PORT_8250) {
590 0 : unsigned char canary = 0xa5;
591 :
592 0 : serial_out(up, UART_SCR, canary);
593 0 : if (serial_in(up, UART_SCR) == canary)
594 0 : up->canary = canary;
595 0 : }
596 :
597 0 : uart_suspend_port(&serial8250_reg, port);
598 0 : }
599 : EXPORT_SYMBOL(serial8250_suspend_port);
600 :
601 : /**
602 : * serial8250_resume_port - resume one serial port
603 : * @line: serial line number
604 : *
605 : * Resume one serial port.
606 : */
607 0 : void serial8250_resume_port(int line)
608 : {
609 0 : struct uart_8250_port *up = &serial8250_ports[line];
610 0 : struct uart_port *port = &up->port;
611 :
612 0 : up->canary = 0;
613 :
614 0 : if (up->capabilities & UART_NATSEMI) {
615 : /* Ensure it's still in high speed mode */
616 0 : serial_port_out(port, UART_LCR, 0xE0);
617 :
618 0 : ns16550a_goto_highspeed(up);
619 :
620 0 : serial_port_out(port, UART_LCR, 0);
621 0 : port->uartclk = 921600*16;
622 0 : }
623 0 : uart_resume_port(&serial8250_reg, port);
624 0 : }
625 : EXPORT_SYMBOL(serial8250_resume_port);
626 :
627 : /*
628 : * serial8250_register_8250_port and serial8250_unregister_port allows for
629 : * 16x50 serial ports to be configured at run-time, to support PCMCIA
630 : * modems and PCI multiport cards.
631 : */
632 : static DEFINE_MUTEX(serial_mutex);
633 :
634 0 : static struct uart_8250_port *serial8250_find_match_or_unused(const struct uart_port *port)
635 : {
636 0 : int i;
637 :
638 : /*
639 : * First, find a port entry which matches.
640 : */
641 0 : for (i = 0; i < nr_uarts; i++)
642 0 : if (uart_match_port(&serial8250_ports[i].port, port))
643 0 : return &serial8250_ports[i];
644 :
645 : /* try line number first if still available */
646 0 : i = port->line;
647 0 : if (i < nr_uarts && serial8250_ports[i].port.type == PORT_UNKNOWN &&
648 0 : serial8250_ports[i].port.iobase == 0)
649 0 : return &serial8250_ports[i];
650 : /*
651 : * We didn't find a matching entry, so look for the first
652 : * free entry. We look for one which hasn't been previously
653 : * used (indicated by zero iobase).
654 : */
655 0 : for (i = 0; i < nr_uarts; i++)
656 0 : if (serial8250_ports[i].port.type == PORT_UNKNOWN &&
657 0 : serial8250_ports[i].port.iobase == 0)
658 0 : return &serial8250_ports[i];
659 :
660 : /*
661 : * That also failed. Last resort is to find any entry which
662 : * doesn't have a real port associated with it.
663 : */
664 0 : for (i = 0; i < nr_uarts; i++)
665 0 : if (serial8250_ports[i].port.type == PORT_UNKNOWN)
666 0 : return &serial8250_ports[i];
667 :
668 0 : return NULL;
669 0 : }
670 :
671 0 : static void serial_8250_overrun_backoff_work(struct work_struct *work)
672 : {
673 0 : struct uart_8250_port *up =
674 0 : container_of(to_delayed_work(work), struct uart_8250_port,
675 : overrun_backoff);
676 0 : struct uart_port *port = &up->port;
677 0 : unsigned long flags;
678 :
679 0 : uart_port_lock_irqsave(port, &flags);
680 0 : up->ier |= UART_IER_RLSI | UART_IER_RDI;
681 0 : serial_out(up, UART_IER, up->ier);
682 0 : uart_port_unlock_irqrestore(port, flags);
683 0 : }
684 :
685 : /**
686 : * serial8250_register_8250_port - register a serial port
687 : * @up: serial port template
688 : *
689 : * Configure the serial port specified by the request. If the
690 : * port exists and is in use, it is hung up and unregistered
691 : * first.
692 : *
693 : * The port is then probed and if necessary the IRQ is autodetected
694 : * If this fails an error is returned.
695 : *
696 : * On success the port is ready to use and the line number is returned.
697 : */
698 0 : int serial8250_register_8250_port(const struct uart_8250_port *up)
699 : {
700 0 : struct uart_8250_port *uart;
701 0 : int ret = -ENOSPC;
702 :
703 0 : if (up->port.uartclk == 0)
704 0 : return -EINVAL;
705 :
706 0 : mutex_lock(&serial_mutex);
707 :
708 0 : uart = serial8250_find_match_or_unused(&up->port);
709 0 : if (!uart) {
710 : /*
711 : * If the port is past the initial isa ports, initialize a new
712 : * port and increment nr_uarts accordingly.
713 : */
714 0 : uart = serial8250_setup_port(nr_uarts);
715 0 : if (!uart)
716 0 : goto unlock;
717 0 : nr_uarts++;
718 0 : }
719 :
720 : /* Check if it is CIR already. We check this below again, see there why. */
721 0 : if (uart->port.type == PORT_8250_CIR) {
722 0 : ret = -ENODEV;
723 0 : goto unlock;
724 : }
725 :
726 0 : if (uart->port.dev)
727 0 : uart_remove_one_port(&serial8250_reg, &uart->port);
728 :
729 0 : uart->port.ctrl_id = up->port.ctrl_id;
730 0 : uart->port.port_id = up->port.port_id;
731 0 : uart->port.iobase = up->port.iobase;
732 0 : uart->port.membase = up->port.membase;
733 0 : uart->port.irq = up->port.irq;
734 0 : uart->port.irqflags = up->port.irqflags;
735 0 : uart->port.uartclk = up->port.uartclk;
736 0 : uart->port.fifosize = up->port.fifosize;
737 0 : uart->port.regshift = up->port.regshift;
738 0 : uart->port.iotype = up->port.iotype;
739 0 : uart->port.flags = up->port.flags | UPF_BOOT_AUTOCONF;
740 0 : uart->bugs = up->bugs;
741 0 : uart->port.mapbase = up->port.mapbase;
742 0 : uart->port.mapsize = up->port.mapsize;
743 0 : uart->port.private_data = up->port.private_data;
744 0 : uart->tx_loadsz = up->tx_loadsz;
745 0 : uart->capabilities = up->capabilities;
746 0 : uart->port.throttle = up->port.throttle;
747 0 : uart->port.unthrottle = up->port.unthrottle;
748 0 : uart->port.rs485_config = up->port.rs485_config;
749 0 : uart->port.rs485_supported = up->port.rs485_supported;
750 0 : uart->port.rs485 = up->port.rs485;
751 0 : uart->rs485_start_tx = up->rs485_start_tx;
752 0 : uart->rs485_stop_tx = up->rs485_stop_tx;
753 0 : uart->lsr_save_mask = up->lsr_save_mask;
754 0 : uart->dma = up->dma;
755 :
756 : /* Take tx_loadsz from fifosize if it wasn't set separately */
757 0 : if (uart->port.fifosize && !uart->tx_loadsz)
758 0 : uart->tx_loadsz = uart->port.fifosize;
759 :
760 0 : if (up->port.dev) {
761 0 : uart->port.dev = up->port.dev;
762 0 : ret = uart_get_rs485_mode(&uart->port);
763 0 : if (ret)
764 0 : goto err;
765 0 : }
766 :
767 0 : if (up->port.flags & UPF_FIXED_TYPE)
768 0 : uart->port.type = up->port.type;
769 :
770 : /*
771 : * Only call mctrl_gpio_init(), if the device has no ACPI
772 : * companion device
773 : */
774 0 : if (!has_acpi_companion(uart->port.dev)) {
775 0 : struct mctrl_gpios *gpios = mctrl_gpio_init(&uart->port, 0);
776 0 : if (IS_ERR(gpios)) {
777 0 : ret = PTR_ERR(gpios);
778 0 : goto err;
779 : } else {
780 0 : uart->gpios = gpios;
781 : }
782 0 : }
783 :
784 0 : serial8250_set_defaults(uart);
785 :
786 : /* Possibly override default I/O functions. */
787 0 : if (up->port.serial_in)
788 0 : uart->port.serial_in = up->port.serial_in;
789 0 : if (up->port.serial_out)
790 0 : uart->port.serial_out = up->port.serial_out;
791 0 : if (up->port.handle_irq)
792 0 : uart->port.handle_irq = up->port.handle_irq;
793 : /* Possibly override set_termios call */
794 0 : if (up->port.set_termios)
795 0 : uart->port.set_termios = up->port.set_termios;
796 0 : if (up->port.set_ldisc)
797 0 : uart->port.set_ldisc = up->port.set_ldisc;
798 0 : if (up->port.get_mctrl)
799 0 : uart->port.get_mctrl = up->port.get_mctrl;
800 0 : if (up->port.set_mctrl)
801 0 : uart->port.set_mctrl = up->port.set_mctrl;
802 0 : if (up->port.get_divisor)
803 0 : uart->port.get_divisor = up->port.get_divisor;
804 0 : if (up->port.set_divisor)
805 0 : uart->port.set_divisor = up->port.set_divisor;
806 0 : if (up->port.startup)
807 0 : uart->port.startup = up->port.startup;
808 0 : if (up->port.shutdown)
809 0 : uart->port.shutdown = up->port.shutdown;
810 0 : if (up->port.pm)
811 0 : uart->port.pm = up->port.pm;
812 0 : if (up->port.handle_break)
813 0 : uart->port.handle_break = up->port.handle_break;
814 0 : if (up->dl_read)
815 0 : uart->dl_read = up->dl_read;
816 0 : if (up->dl_write)
817 0 : uart->dl_write = up->dl_write;
818 :
819 : /* Check the type (again)! It might have changed by the port.type assignment above. */
820 0 : if (uart->port.type != PORT_8250_CIR) {
821 0 : if (uart_console_registered(&uart->port))
822 0 : pm_runtime_get_sync(uart->port.dev);
823 :
824 0 : if (serial8250_isa_config != NULL)
825 0 : serial8250_isa_config(0, &uart->port,
826 0 : &uart->capabilities);
827 :
828 0 : serial8250_apply_quirks(uart);
829 0 : ret = uart_add_one_port(&serial8250_reg,
830 0 : &uart->port);
831 0 : if (ret)
832 0 : goto err;
833 :
834 0 : ret = uart->port.line;
835 0 : } else {
836 0 : dev_info(uart->port.dev,
837 : "skipping CIR port at 0x%lx / 0x%llx, IRQ %d\n",
838 : uart->port.iobase,
839 : (unsigned long long)uart->port.mapbase,
840 : uart->port.irq);
841 :
842 0 : ret = 0;
843 : }
844 :
845 0 : if (!uart->lsr_save_mask)
846 0 : uart->lsr_save_mask = LSR_SAVE_FLAGS; /* Use default LSR mask */
847 :
848 : /* Initialise interrupt backoff work if required */
849 0 : if (up->overrun_backoff_time_ms > 0) {
850 0 : uart->overrun_backoff_time_ms =
851 0 : up->overrun_backoff_time_ms;
852 0 : INIT_DELAYED_WORK(&uart->overrun_backoff,
853 : serial_8250_overrun_backoff_work);
854 0 : } else {
855 0 : uart->overrun_backoff_time_ms = 0;
856 : }
857 :
858 : unlock:
859 0 : mutex_unlock(&serial_mutex);
860 :
861 0 : return ret;
862 :
863 : err:
864 0 : uart->port.dev = NULL;
865 0 : mutex_unlock(&serial_mutex);
866 0 : return ret;
867 0 : }
868 : EXPORT_SYMBOL(serial8250_register_8250_port);
869 :
870 : /**
871 : * serial8250_unregister_port - remove a 16x50 serial port at runtime
872 : * @line: serial line number
873 : *
874 : * Remove one serial port. This may not be called from interrupt
875 : * context. We hand the port back to the our control.
876 : */
877 0 : void serial8250_unregister_port(int line)
878 : {
879 0 : struct uart_8250_port *uart = &serial8250_ports[line];
880 :
881 0 : mutex_lock(&serial_mutex);
882 :
883 0 : if (uart->em485) {
884 0 : unsigned long flags;
885 :
886 0 : uart_port_lock_irqsave(&uart->port, &flags);
887 0 : serial8250_em485_destroy(uart);
888 0 : uart_port_unlock_irqrestore(&uart->port, flags);
889 0 : }
890 :
891 0 : uart_remove_one_port(&serial8250_reg, &uart->port);
892 0 : if (serial8250_isa_devs) {
893 0 : uart->port.flags &= ~UPF_BOOT_AUTOCONF;
894 0 : uart->port.type = PORT_UNKNOWN;
895 0 : uart->port.dev = &serial8250_isa_devs->dev;
896 0 : uart->port.port_id = line;
897 0 : uart->capabilities = 0;
898 0 : serial8250_init_port(uart);
899 0 : serial8250_apply_quirks(uart);
900 0 : uart_add_one_port(&serial8250_reg, &uart->port);
901 0 : } else {
902 0 : uart->port.dev = NULL;
903 : }
904 0 : mutex_unlock(&serial_mutex);
905 0 : }
906 : EXPORT_SYMBOL(serial8250_unregister_port);
907 :
908 : MODULE_LICENSE("GPL");
909 : MODULE_DESCRIPTION("Generic 8250/16x50 serial driver");
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