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/pm_runtime.h>
27 #include <linux/tty.h>
28 #include <linux/ratelimit.h>
29 #include <linux/tty_flip.h>
30 #include <linux/serial.h>
31 #include <linux/serial_8250.h>
32 #include <linux/nmi.h>
33 #include <linux/mutex.h>
34 #include <linux/slab.h>
35 #include <linux/uaccess.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 irq_info *i;
176 int ret;
177
178 mutex_lock(&hash_mutex);
179
180 h = &irq_lists[up->port.irq % NR_IRQ_HASH];
181
182 hlist_for_each_entry(i, h, node)
183 if (i->irq == up->port.irq)
184 break;
185
186 if (i == NULL) {
187 i = kzalloc(sizeof(struct irq_info), GFP_KERNEL);
188 if (i == NULL) {
189 mutex_unlock(&hash_mutex);
190 return -ENOMEM;
191 }
192 spin_lock_init(&i->lock);
193 i->irq = up->port.irq;
194 hlist_add_head(&i->node, h);
195 }
196 mutex_unlock(&hash_mutex);
197
198 spin_lock_irq(&i->lock);
199
200 if (i->head) {
201 list_add(&up->list, i->head);
202 spin_unlock_irq(&i->lock);
203
204 ret = 0;
205 } else {
206 INIT_LIST_HEAD(&up->list);
207 i->head = &up->list;
208 spin_unlock_irq(&i->lock);
209 ret = request_irq(up->port.irq, serial8250_interrupt,
210 up->port.irqflags, up->port.name, i);
211 if (ret < 0)
212 serial_do_unlink(i, up);
213 }
214
215 return ret;
216 }
217
serial_unlink_irq_chain(struct uart_8250_port * up)218 static void serial_unlink_irq_chain(struct uart_8250_port *up)
219 {
220 struct irq_info *i;
221 struct hlist_head *h;
222
223 mutex_lock(&hash_mutex);
224
225 h = &irq_lists[up->port.irq % NR_IRQ_HASH];
226
227 hlist_for_each_entry(i, h, node)
228 if (i->irq == up->port.irq)
229 break;
230
231 BUG_ON(i == NULL);
232 BUG_ON(i->head == NULL);
233
234 if (list_empty(i->head))
235 free_irq(up->port.irq, i);
236
237 serial_do_unlink(i, up);
238 mutex_unlock(&hash_mutex);
239 }
240
241 /*
242 * This function is used to handle ports that do not have an
243 * interrupt. This doesn't work very well for 16450's, but gives
244 * barely passable results for a 16550A. (Although at the expense
245 * of much CPU overhead).
246 */
serial8250_timeout(struct timer_list * t)247 static void serial8250_timeout(struct timer_list *t)
248 {
249 struct uart_8250_port *up = from_timer(up, t, timer);
250
251 up->port.handle_irq(&up->port);
252 mod_timer(&up->timer, jiffies + uart_poll_timeout(&up->port));
253 }
254
serial8250_backup_timeout(struct timer_list * t)255 static void serial8250_backup_timeout(struct timer_list *t)
256 {
257 struct uart_8250_port *up = from_timer(up, t, timer);
258 unsigned int iir, ier = 0, lsr;
259 unsigned long flags;
260
261 spin_lock_irqsave(&up->port.lock, flags);
262
263 /*
264 * Must disable interrupts or else we risk racing with the interrupt
265 * based handler.
266 */
267 if (up->port.irq) {
268 ier = serial_in(up, UART_IER);
269 serial_out(up, UART_IER, 0);
270 }
271
272 iir = serial_in(up, UART_IIR);
273
274 /*
275 * This should be a safe test for anyone who doesn't trust the
276 * IIR bits on their UART, but it's specifically designed for
277 * the "Diva" UART used on the management processor on many HP
278 * ia64 and parisc boxes.
279 */
280 lsr = serial_lsr_in(up);
281 if ((iir & UART_IIR_NO_INT) && (up->ier & UART_IER_THRI) &&
282 (!uart_circ_empty(&up->port.state->xmit) || up->port.x_char) &&
283 (lsr & UART_LSR_THRE)) {
284 iir &= ~(UART_IIR_ID | UART_IIR_NO_INT);
285 iir |= UART_IIR_THRI;
286 }
287
288 if (!(iir & UART_IIR_NO_INT))
289 serial8250_tx_chars(up);
290
291 if (up->port.irq)
292 serial_out(up, UART_IER, ier);
293
294 spin_unlock_irqrestore(&up->port.lock, flags);
295
296 /* Standard timer interval plus 0.2s to keep the port running */
297 mod_timer(&up->timer,
298 jiffies + uart_poll_timeout(&up->port) + HZ / 5);
299 }
300
univ8250_setup_irq(struct uart_8250_port * up)301 static int univ8250_setup_irq(struct uart_8250_port *up)
302 {
303 struct uart_port *port = &up->port;
304 int retval = 0;
305
306 /*
307 * The above check will only give an accurate result the first time
308 * the port is opened so this value needs to be preserved.
309 */
310 if (up->bugs & UART_BUG_THRE) {
311 pr_debug("%s - using backup timer\n", port->name);
312
313 up->timer.function = serial8250_backup_timeout;
314 mod_timer(&up->timer, jiffies +
315 uart_poll_timeout(port) + HZ / 5);
316 }
317
318 /*
319 * If the "interrupt" for this port doesn't correspond with any
320 * hardware interrupt, we use a timer-based system. The original
321 * driver used to do this with IRQ0.
322 */
323 if (!port->irq)
324 mod_timer(&up->timer, jiffies + uart_poll_timeout(port));
325 else
326 retval = serial_link_irq_chain(up);
327
328 return retval;
329 }
330
univ8250_release_irq(struct uart_8250_port * up)331 static void univ8250_release_irq(struct uart_8250_port *up)
332 {
333 struct uart_port *port = &up->port;
334
335 del_timer_sync(&up->timer);
336 up->timer.function = serial8250_timeout;
337 if (port->irq)
338 serial_unlink_irq_chain(up);
339 }
340
341 #ifdef CONFIG_SERIAL_8250_RSA
serial8250_request_rsa_resource(struct uart_8250_port * up)342 static int serial8250_request_rsa_resource(struct uart_8250_port *up)
343 {
344 unsigned long start = UART_RSA_BASE << up->port.regshift;
345 unsigned int size = 8 << up->port.regshift;
346 struct uart_port *port = &up->port;
347 int ret = -EINVAL;
348
349 switch (port->iotype) {
350 case UPIO_HUB6:
351 case UPIO_PORT:
352 start += port->iobase;
353 if (request_region(start, size, "serial-rsa"))
354 ret = 0;
355 else
356 ret = -EBUSY;
357 break;
358 }
359
360 return ret;
361 }
362
serial8250_release_rsa_resource(struct uart_8250_port * up)363 static void serial8250_release_rsa_resource(struct uart_8250_port *up)
364 {
365 unsigned long offset = UART_RSA_BASE << up->port.regshift;
366 unsigned int size = 8 << up->port.regshift;
367 struct uart_port *port = &up->port;
368
369 switch (port->iotype) {
370 case UPIO_HUB6:
371 case UPIO_PORT:
372 release_region(port->iobase + offset, size);
373 break;
374 }
375 }
376 #endif
377
378 static const struct uart_ops *base_ops;
379 static struct uart_ops univ8250_port_ops;
380
381 static const struct uart_8250_ops univ8250_driver_ops = {
382 .setup_irq = univ8250_setup_irq,
383 .release_irq = univ8250_release_irq,
384 };
385
386 static struct uart_8250_port serial8250_ports[UART_NR];
387
388 /**
389 * serial8250_get_port - retrieve struct uart_8250_port
390 * @line: serial line number
391 *
392 * This function retrieves struct uart_8250_port for the specific line.
393 * This struct *must* *not* be used to perform a 8250 or serial core operation
394 * which is not accessible otherwise. Its only purpose is to make the struct
395 * accessible to the runtime-pm callbacks for context suspend/restore.
396 * The lock assumption made here is none because runtime-pm suspend/resume
397 * callbacks should not be invoked if there is any operation performed on the
398 * port.
399 */
serial8250_get_port(int line)400 struct uart_8250_port *serial8250_get_port(int line)
401 {
402 return &serial8250_ports[line];
403 }
404 EXPORT_SYMBOL_GPL(serial8250_get_port);
405
406 static void (*serial8250_isa_config)(int port, struct uart_port *up,
407 u32 *capabilities);
408
serial8250_set_isa_configurator(void (* v)(int port,struct uart_port * up,u32 * capabilities))409 void serial8250_set_isa_configurator(
410 void (*v)(int port, struct uart_port *up, u32 *capabilities))
411 {
412 serial8250_isa_config = v;
413 }
414 EXPORT_SYMBOL(serial8250_set_isa_configurator);
415
416 #ifdef CONFIG_SERIAL_8250_RSA
417
univ8250_config_port(struct uart_port * port,int flags)418 static void univ8250_config_port(struct uart_port *port, int flags)
419 {
420 struct uart_8250_port *up = up_to_u8250p(port);
421
422 up->probe &= ~UART_PROBE_RSA;
423 if (port->type == PORT_RSA) {
424 if (serial8250_request_rsa_resource(up) == 0)
425 up->probe |= UART_PROBE_RSA;
426 } else if (flags & UART_CONFIG_TYPE) {
427 int i;
428
429 for (i = 0; i < probe_rsa_count; i++) {
430 if (probe_rsa[i] == up->port.iobase) {
431 if (serial8250_request_rsa_resource(up) == 0)
432 up->probe |= UART_PROBE_RSA;
433 break;
434 }
435 }
436 }
437
438 base_ops->config_port(port, flags);
439
440 if (port->type != PORT_RSA && up->probe & UART_PROBE_RSA)
441 serial8250_release_rsa_resource(up);
442 }
443
univ8250_request_port(struct uart_port * port)444 static int univ8250_request_port(struct uart_port *port)
445 {
446 struct uart_8250_port *up = up_to_u8250p(port);
447 int ret;
448
449 ret = base_ops->request_port(port);
450 if (ret == 0 && port->type == PORT_RSA) {
451 ret = serial8250_request_rsa_resource(up);
452 if (ret < 0)
453 base_ops->release_port(port);
454 }
455
456 return ret;
457 }
458
univ8250_release_port(struct uart_port * port)459 static void univ8250_release_port(struct uart_port *port)
460 {
461 struct uart_8250_port *up = up_to_u8250p(port);
462
463 if (port->type == PORT_RSA)
464 serial8250_release_rsa_resource(up);
465 base_ops->release_port(port);
466 }
467
univ8250_rsa_support(struct uart_ops * ops)468 static void univ8250_rsa_support(struct uart_ops *ops)
469 {
470 ops->config_port = univ8250_config_port;
471 ops->request_port = univ8250_request_port;
472 ops->release_port = univ8250_release_port;
473 }
474
475 #else
476 #define univ8250_rsa_support(x) do { } while (0)
477 #endif /* CONFIG_SERIAL_8250_RSA */
478
serial8250_apply_quirks(struct uart_8250_port * up)479 static inline void serial8250_apply_quirks(struct uart_8250_port *up)
480 {
481 up->port.quirks |= skip_txen_test ? UPQ_NO_TXEN_TEST : 0;
482 }
483
serial8250_isa_init_ports(void)484 static void __init serial8250_isa_init_ports(void)
485 {
486 struct uart_8250_port *up;
487 static int first = 1;
488 int i, irqflag = 0;
489
490 if (!first)
491 return;
492 first = 0;
493
494 if (nr_uarts > UART_NR)
495 nr_uarts = UART_NR;
496
497 for (i = 0; i < nr_uarts; i++) {
498 struct uart_8250_port *up = &serial8250_ports[i];
499 struct uart_port *port = &up->port;
500
501 port->line = i;
502 serial8250_init_port(up);
503 if (!base_ops)
504 base_ops = port->ops;
505 port->ops = &univ8250_port_ops;
506
507 timer_setup(&up->timer, serial8250_timeout, 0);
508
509 up->ops = &univ8250_driver_ops;
510
511 if (IS_ENABLED(CONFIG_ALPHA_JENSEN) ||
512 (IS_ENABLED(CONFIG_ALPHA_GENERIC) && alpha_jensen()))
513 port->set_mctrl = alpha_jensen_set_mctrl;
514
515 serial8250_set_defaults(up);
516 }
517
518 /* chain base port ops to support Remote Supervisor Adapter */
519 univ8250_port_ops = *base_ops;
520 univ8250_rsa_support(&univ8250_port_ops);
521
522 if (share_irqs)
523 irqflag = IRQF_SHARED;
524
525 for (i = 0, up = serial8250_ports;
526 i < ARRAY_SIZE(old_serial_port) && i < nr_uarts;
527 i++, up++) {
528 struct uart_port *port = &up->port;
529
530 port->iobase = old_serial_port[i].port;
531 port->irq = irq_canonicalize(old_serial_port[i].irq);
532 port->irqflags = 0;
533 port->uartclk = old_serial_port[i].baud_base * 16;
534 port->flags = old_serial_port[i].flags;
535 port->hub6 = 0;
536 port->membase = old_serial_port[i].iomem_base;
537 port->iotype = old_serial_port[i].io_type;
538 port->regshift = old_serial_port[i].iomem_reg_shift;
539
540 port->irqflags |= irqflag;
541 if (serial8250_isa_config != NULL)
542 serial8250_isa_config(i, &up->port, &up->capabilities);
543 }
544 }
545
546 static void __init
serial8250_register_ports(struct uart_driver * drv,struct device * dev)547 serial8250_register_ports(struct uart_driver *drv, struct device *dev)
548 {
549 int i;
550
551 for (i = 0; i < nr_uarts; i++) {
552 struct uart_8250_port *up = &serial8250_ports[i];
553
554 if (up->port.type == PORT_8250_CIR)
555 continue;
556
557 if (up->port.dev)
558 continue;
559
560 up->port.dev = dev;
561
562 if (uart_console_enabled(&up->port))
563 pm_runtime_get_sync(up->port.dev);
564
565 serial8250_apply_quirks(up);
566 uart_add_one_port(drv, &up->port);
567 }
568 }
569
570 #ifdef CONFIG_SERIAL_8250_CONSOLE
571
univ8250_console_write(struct console * co,const char * s,unsigned int count)572 static void univ8250_console_write(struct console *co, const char *s,
573 unsigned int count)
574 {
575 struct uart_8250_port *up = &serial8250_ports[co->index];
576
577 serial8250_console_write(up, s, count);
578 }
579
univ8250_console_setup(struct console * co,char * options)580 static int univ8250_console_setup(struct console *co, char *options)
581 {
582 struct uart_port *port;
583 int retval;
584
585 /*
586 * Check whether an invalid uart number has been specified, and
587 * if so, search for the first available port that does have
588 * console support.
589 */
590 if (co->index >= nr_uarts)
591 co->index = 0;
592 port = &serial8250_ports[co->index].port;
593 /* link port to console */
594 port->cons = co;
595
596 retval = serial8250_console_setup(port, options, false);
597 if (retval != 0)
598 port->cons = NULL;
599 return retval;
600 }
601
univ8250_console_exit(struct console * co)602 static int univ8250_console_exit(struct console *co)
603 {
604 struct uart_port *port;
605
606 port = &serial8250_ports[co->index].port;
607 return serial8250_console_exit(port);
608 }
609
610 /**
611 * univ8250_console_match - non-standard console matching
612 * @co: registering console
613 * @name: name from console command line
614 * @idx: index from console command line
615 * @options: ptr to option string from console command line
616 *
617 * Only attempts to match console command lines of the form:
618 * console=uart[8250],io|mmio|mmio16|mmio32,<addr>[,<options>]
619 * console=uart[8250],0x<addr>[,<options>]
620 * This form is used to register an initial earlycon boot console and
621 * replace it with the serial8250_console at 8250 driver init.
622 *
623 * Performs console setup for a match (as required by interface)
624 * If no <options> are specified, then assume the h/w is already setup.
625 *
626 * Returns 0 if console matches; otherwise non-zero to use default matching
627 */
univ8250_console_match(struct console * co,char * name,int idx,char * options)628 static int univ8250_console_match(struct console *co, char *name, int idx,
629 char *options)
630 {
631 char match[] = "uart"; /* 8250-specific earlycon name */
632 unsigned char iotype;
633 resource_size_t addr;
634 int i;
635
636 if (strncmp(name, match, 4) != 0)
637 return -ENODEV;
638
639 if (uart_parse_earlycon(options, &iotype, &addr, &options))
640 return -ENODEV;
641
642 /* try to match the port specified on the command line */
643 for (i = 0; i < nr_uarts; i++) {
644 struct uart_port *port = &serial8250_ports[i].port;
645
646 if (port->iotype != iotype)
647 continue;
648 if ((iotype == UPIO_MEM || iotype == UPIO_MEM16 ||
649 iotype == UPIO_MEM32 || iotype == UPIO_MEM32BE)
650 && (port->mapbase != addr))
651 continue;
652 if (iotype == UPIO_PORT && port->iobase != addr)
653 continue;
654
655 co->index = i;
656 port->cons = co;
657 return serial8250_console_setup(port, options, true);
658 }
659
660 return -ENODEV;
661 }
662
663 static struct console univ8250_console = {
664 .name = "ttyS",
665 .write = univ8250_console_write,
666 .device = uart_console_device,
667 .setup = univ8250_console_setup,
668 .exit = univ8250_console_exit,
669 .match = univ8250_console_match,
670 .flags = CON_PRINTBUFFER | CON_ANYTIME,
671 .index = -1,
672 .data = &serial8250_reg,
673 };
674
univ8250_console_init(void)675 static int __init univ8250_console_init(void)
676 {
677 if (nr_uarts == 0)
678 return -ENODEV;
679
680 serial8250_isa_init_ports();
681 register_console(&univ8250_console);
682 return 0;
683 }
684 console_initcall(univ8250_console_init);
685
686 #define SERIAL8250_CONSOLE (&univ8250_console)
687 #else
688 #define SERIAL8250_CONSOLE NULL
689 #endif
690
691 static struct uart_driver serial8250_reg = {
692 .owner = THIS_MODULE,
693 .driver_name = "serial",
694 .dev_name = "ttyS",
695 .major = TTY_MAJOR,
696 .minor = 64,
697 .cons = SERIAL8250_CONSOLE,
698 };
699
700 /*
701 * early_serial_setup - early registration for 8250 ports
702 *
703 * Setup an 8250 port structure prior to console initialisation. Use
704 * after console initialisation will cause undefined behaviour.
705 */
early_serial_setup(struct uart_port * port)706 int __init early_serial_setup(struct uart_port *port)
707 {
708 struct uart_port *p;
709
710 if (port->line >= ARRAY_SIZE(serial8250_ports) || nr_uarts == 0)
711 return -ENODEV;
712
713 serial8250_isa_init_ports();
714 p = &serial8250_ports[port->line].port;
715 p->iobase = port->iobase;
716 p->membase = port->membase;
717 p->irq = port->irq;
718 p->irqflags = port->irqflags;
719 p->uartclk = port->uartclk;
720 p->fifosize = port->fifosize;
721 p->regshift = port->regshift;
722 p->iotype = port->iotype;
723 p->flags = port->flags;
724 p->mapbase = port->mapbase;
725 p->mapsize = port->mapsize;
726 p->private_data = port->private_data;
727 p->type = port->type;
728 p->line = port->line;
729
730 serial8250_set_defaults(up_to_u8250p(p));
731
732 if (port->serial_in)
733 p->serial_in = port->serial_in;
734 if (port->serial_out)
735 p->serial_out = port->serial_out;
736 if (port->handle_irq)
737 p->handle_irq = port->handle_irq;
738
739 return 0;
740 }
741
742 /**
743 * serial8250_suspend_port - suspend one serial port
744 * @line: serial line number
745 *
746 * Suspend one serial port.
747 */
serial8250_suspend_port(int line)748 void serial8250_suspend_port(int line)
749 {
750 struct uart_8250_port *up = &serial8250_ports[line];
751 struct uart_port *port = &up->port;
752
753 if (!console_suspend_enabled && uart_console(port) &&
754 port->type != PORT_8250) {
755 unsigned char canary = 0xa5;
756
757 serial_out(up, UART_SCR, canary);
758 if (serial_in(up, UART_SCR) == canary)
759 up->canary = canary;
760 }
761
762 uart_suspend_port(&serial8250_reg, port);
763 }
764 EXPORT_SYMBOL(serial8250_suspend_port);
765
766 /**
767 * serial8250_resume_port - resume one serial port
768 * @line: serial line number
769 *
770 * Resume one serial port.
771 */
serial8250_resume_port(int line)772 void serial8250_resume_port(int line)
773 {
774 struct uart_8250_port *up = &serial8250_ports[line];
775 struct uart_port *port = &up->port;
776
777 up->canary = 0;
778
779 if (up->capabilities & UART_NATSEMI) {
780 /* Ensure it's still in high speed mode */
781 serial_port_out(port, UART_LCR, 0xE0);
782
783 ns16550a_goto_highspeed(up);
784
785 serial_port_out(port, UART_LCR, 0);
786 port->uartclk = 921600*16;
787 }
788 uart_resume_port(&serial8250_reg, port);
789 }
790 EXPORT_SYMBOL(serial8250_resume_port);
791
792 /*
793 * Register a set of serial devices attached to a platform device. The
794 * list is terminated with a zero flags entry, which means we expect
795 * all entries to have at least UPF_BOOT_AUTOCONF set.
796 */
serial8250_probe(struct platform_device * dev)797 static int serial8250_probe(struct platform_device *dev)
798 {
799 struct plat_serial8250_port *p = dev_get_platdata(&dev->dev);
800 struct uart_8250_port uart;
801 int ret, i, irqflag = 0;
802
803 memset(&uart, 0, sizeof(uart));
804
805 if (share_irqs)
806 irqflag = IRQF_SHARED;
807
808 for (i = 0; p && p->flags != 0; p++, i++) {
809 uart.port.iobase = p->iobase;
810 uart.port.membase = p->membase;
811 uart.port.irq = p->irq;
812 uart.port.irqflags = p->irqflags;
813 uart.port.uartclk = p->uartclk;
814 uart.port.regshift = p->regshift;
815 uart.port.iotype = p->iotype;
816 uart.port.flags = p->flags;
817 uart.port.mapbase = p->mapbase;
818 uart.port.hub6 = p->hub6;
819 uart.port.has_sysrq = p->has_sysrq;
820 uart.port.private_data = p->private_data;
821 uart.port.type = p->type;
822 uart.port.serial_in = p->serial_in;
823 uart.port.serial_out = p->serial_out;
824 uart.port.handle_irq = p->handle_irq;
825 uart.port.handle_break = p->handle_break;
826 uart.port.set_termios = p->set_termios;
827 uart.port.set_ldisc = p->set_ldisc;
828 uart.port.get_mctrl = p->get_mctrl;
829 uart.port.pm = p->pm;
830 uart.port.dev = &dev->dev;
831 uart.port.irqflags |= irqflag;
832 ret = serial8250_register_8250_port(&uart);
833 if (ret < 0) {
834 dev_err(&dev->dev, "unable to register port at index %d "
835 "(IO%lx MEM%llx IRQ%d): %d\n", i,
836 p->iobase, (unsigned long long)p->mapbase,
837 p->irq, ret);
838 }
839 }
840 return 0;
841 }
842
843 /*
844 * Remove serial ports registered against a platform device.
845 */
serial8250_remove(struct platform_device * dev)846 static int serial8250_remove(struct platform_device *dev)
847 {
848 int i;
849
850 for (i = 0; i < nr_uarts; i++) {
851 struct uart_8250_port *up = &serial8250_ports[i];
852
853 if (up->port.dev == &dev->dev)
854 serial8250_unregister_port(i);
855 }
856 return 0;
857 }
858
serial8250_suspend(struct platform_device * dev,pm_message_t state)859 static int serial8250_suspend(struct platform_device *dev, pm_message_t state)
860 {
861 int i;
862
863 for (i = 0; i < UART_NR; i++) {
864 struct uart_8250_port *up = &serial8250_ports[i];
865
866 if (up->port.type != PORT_UNKNOWN && up->port.dev == &dev->dev)
867 uart_suspend_port(&serial8250_reg, &up->port);
868 }
869
870 return 0;
871 }
872
serial8250_resume(struct platform_device * dev)873 static int serial8250_resume(struct platform_device *dev)
874 {
875 int i;
876
877 for (i = 0; i < UART_NR; i++) {
878 struct uart_8250_port *up = &serial8250_ports[i];
879
880 if (up->port.type != PORT_UNKNOWN && up->port.dev == &dev->dev)
881 serial8250_resume_port(i);
882 }
883
884 return 0;
885 }
886
887 static struct platform_driver serial8250_isa_driver = {
888 .probe = serial8250_probe,
889 .remove = serial8250_remove,
890 .suspend = serial8250_suspend,
891 .resume = serial8250_resume,
892 .driver = {
893 .name = "serial8250",
894 },
895 };
896
897 /*
898 * This "device" covers _all_ ISA 8250-compatible serial devices listed
899 * in the table in include/asm/serial.h
900 */
901 static struct platform_device *serial8250_isa_devs;
902
903 /*
904 * serial8250_register_8250_port and serial8250_unregister_port allows for
905 * 16x50 serial ports to be configured at run-time, to support PCMCIA
906 * modems and PCI multiport cards.
907 */
908 static DEFINE_MUTEX(serial_mutex);
909
serial8250_find_match_or_unused(const struct uart_port * port)910 static struct uart_8250_port *serial8250_find_match_or_unused(const struct uart_port *port)
911 {
912 int i;
913
914 /*
915 * First, find a port entry which matches.
916 */
917 for (i = 0; i < nr_uarts; i++)
918 if (uart_match_port(&serial8250_ports[i].port, port))
919 return &serial8250_ports[i];
920
921 /* try line number first if still available */
922 i = port->line;
923 if (i < nr_uarts && serial8250_ports[i].port.type == PORT_UNKNOWN &&
924 serial8250_ports[i].port.iobase == 0)
925 return &serial8250_ports[i];
926 /*
927 * We didn't find a matching entry, so look for the first
928 * free entry. We look for one which hasn't been previously
929 * used (indicated by zero iobase).
930 */
931 for (i = 0; i < nr_uarts; i++)
932 if (serial8250_ports[i].port.type == PORT_UNKNOWN &&
933 serial8250_ports[i].port.iobase == 0)
934 return &serial8250_ports[i];
935
936 /*
937 * That also failed. Last resort is to find any entry which
938 * doesn't have a real port associated with it.
939 */
940 for (i = 0; i < nr_uarts; i++)
941 if (serial8250_ports[i].port.type == PORT_UNKNOWN)
942 return &serial8250_ports[i];
943
944 return NULL;
945 }
946
serial_8250_overrun_backoff_work(struct work_struct * work)947 static void serial_8250_overrun_backoff_work(struct work_struct *work)
948 {
949 struct uart_8250_port *up =
950 container_of(to_delayed_work(work), struct uart_8250_port,
951 overrun_backoff);
952 struct uart_port *port = &up->port;
953 unsigned long flags;
954
955 spin_lock_irqsave(&port->lock, flags);
956 up->ier |= UART_IER_RLSI | UART_IER_RDI;
957 up->port.read_status_mask |= UART_LSR_DR;
958 serial_out(up, UART_IER, up->ier);
959 spin_unlock_irqrestore(&port->lock, flags);
960 }
961
962 /**
963 * serial8250_register_8250_port - register a serial port
964 * @up: serial port template
965 *
966 * Configure the serial port specified by the request. If the
967 * port exists and is in use, it is hung up and unregistered
968 * first.
969 *
970 * The port is then probed and if necessary the IRQ is autodetected
971 * If this fails an error is returned.
972 *
973 * On success the port is ready to use and the line number is returned.
974 */
serial8250_register_8250_port(const struct uart_8250_port * up)975 int serial8250_register_8250_port(const struct uart_8250_port *up)
976 {
977 struct uart_8250_port *uart;
978 int ret = -ENOSPC;
979
980 if (up->port.uartclk == 0)
981 return -EINVAL;
982
983 mutex_lock(&serial_mutex);
984
985 uart = serial8250_find_match_or_unused(&up->port);
986 if (uart && uart->port.type != PORT_8250_CIR) {
987 struct mctrl_gpios *gpios;
988
989 if (uart->port.dev)
990 uart_remove_one_port(&serial8250_reg, &uart->port);
991
992 uart->port.iobase = up->port.iobase;
993 uart->port.membase = up->port.membase;
994 uart->port.irq = up->port.irq;
995 uart->port.irqflags = up->port.irqflags;
996 uart->port.uartclk = up->port.uartclk;
997 uart->port.fifosize = up->port.fifosize;
998 uart->port.regshift = up->port.regshift;
999 uart->port.iotype = up->port.iotype;
1000 uart->port.flags = up->port.flags | UPF_BOOT_AUTOCONF;
1001 uart->bugs = up->bugs;
1002 uart->port.mapbase = up->port.mapbase;
1003 uart->port.mapsize = up->port.mapsize;
1004 uart->port.private_data = up->port.private_data;
1005 uart->tx_loadsz = up->tx_loadsz;
1006 uart->capabilities = up->capabilities;
1007 uart->port.throttle = up->port.throttle;
1008 uart->port.unthrottle = up->port.unthrottle;
1009 uart->port.rs485_config = up->port.rs485_config;
1010 uart->port.rs485 = up->port.rs485;
1011 uart->rs485_start_tx = up->rs485_start_tx;
1012 uart->rs485_stop_tx = up->rs485_stop_tx;
1013 uart->dma = up->dma;
1014
1015 /* Take tx_loadsz from fifosize if it wasn't set separately */
1016 if (uart->port.fifosize && !uart->tx_loadsz)
1017 uart->tx_loadsz = uart->port.fifosize;
1018
1019 if (up->port.dev) {
1020 uart->port.dev = up->port.dev;
1021 ret = uart_get_rs485_mode(&uart->port);
1022 if (ret)
1023 goto err;
1024 }
1025
1026 if (up->port.flags & UPF_FIXED_TYPE)
1027 uart->port.type = up->port.type;
1028
1029 /*
1030 * Only call mctrl_gpio_init(), if the device has no ACPI
1031 * companion device
1032 */
1033 if (!has_acpi_companion(uart->port.dev)) {
1034 gpios = mctrl_gpio_init(&uart->port, 0);
1035 if (IS_ERR(gpios)) {
1036 ret = PTR_ERR(gpios);
1037 goto err;
1038 } else {
1039 uart->gpios = gpios;
1040 }
1041 }
1042
1043 serial8250_set_defaults(uart);
1044
1045 /* Possibly override default I/O functions. */
1046 if (up->port.serial_in)
1047 uart->port.serial_in = up->port.serial_in;
1048 if (up->port.serial_out)
1049 uart->port.serial_out = up->port.serial_out;
1050 if (up->port.handle_irq)
1051 uart->port.handle_irq = up->port.handle_irq;
1052 /* Possibly override set_termios call */
1053 if (up->port.set_termios)
1054 uart->port.set_termios = up->port.set_termios;
1055 if (up->port.set_ldisc)
1056 uart->port.set_ldisc = up->port.set_ldisc;
1057 if (up->port.get_mctrl)
1058 uart->port.get_mctrl = up->port.get_mctrl;
1059 if (up->port.set_mctrl)
1060 uart->port.set_mctrl = up->port.set_mctrl;
1061 if (up->port.get_divisor)
1062 uart->port.get_divisor = up->port.get_divisor;
1063 if (up->port.set_divisor)
1064 uart->port.set_divisor = up->port.set_divisor;
1065 if (up->port.startup)
1066 uart->port.startup = up->port.startup;
1067 if (up->port.shutdown)
1068 uart->port.shutdown = up->port.shutdown;
1069 if (up->port.pm)
1070 uart->port.pm = up->port.pm;
1071 if (up->port.handle_break)
1072 uart->port.handle_break = up->port.handle_break;
1073 if (up->dl_read)
1074 uart->dl_read = up->dl_read;
1075 if (up->dl_write)
1076 uart->dl_write = up->dl_write;
1077
1078 if (uart->port.type != PORT_8250_CIR) {
1079 if (serial8250_isa_config != NULL)
1080 serial8250_isa_config(0, &uart->port,
1081 &uart->capabilities);
1082
1083 serial8250_apply_quirks(uart);
1084 ret = uart_add_one_port(&serial8250_reg,
1085 &uart->port);
1086 if (ret)
1087 goto err;
1088
1089 ret = uart->port.line;
1090 } else {
1091 dev_info(uart->port.dev,
1092 "skipping CIR port at 0x%lx / 0x%llx, IRQ %d\n",
1093 uart->port.iobase,
1094 (unsigned long long)uart->port.mapbase,
1095 uart->port.irq);
1096
1097 ret = 0;
1098 }
1099
1100 /* Initialise interrupt backoff work if required */
1101 if (up->overrun_backoff_time_ms > 0) {
1102 uart->overrun_backoff_time_ms =
1103 up->overrun_backoff_time_ms;
1104 INIT_DELAYED_WORK(&uart->overrun_backoff,
1105 serial_8250_overrun_backoff_work);
1106 } else {
1107 uart->overrun_backoff_time_ms = 0;
1108 }
1109 }
1110
1111 mutex_unlock(&serial_mutex);
1112
1113 return ret;
1114
1115 err:
1116 uart->port.dev = NULL;
1117 mutex_unlock(&serial_mutex);
1118 return ret;
1119 }
1120 EXPORT_SYMBOL(serial8250_register_8250_port);
1121
1122 /**
1123 * serial8250_unregister_port - remove a 16x50 serial port at runtime
1124 * @line: serial line number
1125 *
1126 * Remove one serial port. This may not be called from interrupt
1127 * context. We hand the port back to the our control.
1128 */
serial8250_unregister_port(int line)1129 void serial8250_unregister_port(int line)
1130 {
1131 struct uart_8250_port *uart = &serial8250_ports[line];
1132
1133 mutex_lock(&serial_mutex);
1134
1135 if (uart->em485) {
1136 unsigned long flags;
1137
1138 spin_lock_irqsave(&uart->port.lock, flags);
1139 serial8250_em485_destroy(uart);
1140 spin_unlock_irqrestore(&uart->port.lock, flags);
1141 }
1142
1143 uart_remove_one_port(&serial8250_reg, &uart->port);
1144 if (serial8250_isa_devs) {
1145 uart->port.flags &= ~UPF_BOOT_AUTOCONF;
1146 uart->port.type = PORT_UNKNOWN;
1147 uart->port.dev = &serial8250_isa_devs->dev;
1148 uart->capabilities = 0;
1149 serial8250_apply_quirks(uart);
1150 uart_add_one_port(&serial8250_reg, &uart->port);
1151 } else {
1152 uart->port.dev = NULL;
1153 }
1154 mutex_unlock(&serial_mutex);
1155 }
1156 EXPORT_SYMBOL(serial8250_unregister_port);
1157
serial8250_init(void)1158 static int __init serial8250_init(void)
1159 {
1160 int ret;
1161
1162 if (nr_uarts == 0)
1163 return -ENODEV;
1164
1165 serial8250_isa_init_ports();
1166
1167 pr_info("Serial: 8250/16550 driver, %d ports, IRQ sharing %sabled\n",
1168 nr_uarts, share_irqs ? "en" : "dis");
1169
1170 #ifdef CONFIG_SPARC
1171 ret = sunserial_register_minors(&serial8250_reg, UART_NR);
1172 #else
1173 serial8250_reg.nr = UART_NR;
1174 ret = uart_register_driver(&serial8250_reg);
1175 #endif
1176 if (ret)
1177 goto out;
1178
1179 ret = serial8250_pnp_init();
1180 if (ret)
1181 goto unreg_uart_drv;
1182
1183 serial8250_isa_devs = platform_device_alloc("serial8250",
1184 PLAT8250_DEV_LEGACY);
1185 if (!serial8250_isa_devs) {
1186 ret = -ENOMEM;
1187 goto unreg_pnp;
1188 }
1189
1190 ret = platform_device_add(serial8250_isa_devs);
1191 if (ret)
1192 goto put_dev;
1193
1194 serial8250_register_ports(&serial8250_reg, &serial8250_isa_devs->dev);
1195
1196 ret = platform_driver_register(&serial8250_isa_driver);
1197 if (ret == 0)
1198 goto out;
1199
1200 platform_device_del(serial8250_isa_devs);
1201 put_dev:
1202 platform_device_put(serial8250_isa_devs);
1203 unreg_pnp:
1204 serial8250_pnp_exit();
1205 unreg_uart_drv:
1206 #ifdef CONFIG_SPARC
1207 sunserial_unregister_minors(&serial8250_reg, UART_NR);
1208 #else
1209 uart_unregister_driver(&serial8250_reg);
1210 #endif
1211 out:
1212 return ret;
1213 }
1214
serial8250_exit(void)1215 static void __exit serial8250_exit(void)
1216 {
1217 struct platform_device *isa_dev = serial8250_isa_devs;
1218
1219 /*
1220 * This tells serial8250_unregister_port() not to re-register
1221 * the ports (thereby making serial8250_isa_driver permanently
1222 * in use.)
1223 */
1224 serial8250_isa_devs = NULL;
1225
1226 platform_driver_unregister(&serial8250_isa_driver);
1227 platform_device_unregister(isa_dev);
1228
1229 serial8250_pnp_exit();
1230
1231 #ifdef CONFIG_SPARC
1232 sunserial_unregister_minors(&serial8250_reg, UART_NR);
1233 #else
1234 uart_unregister_driver(&serial8250_reg);
1235 #endif
1236 }
1237
1238 module_init(serial8250_init);
1239 module_exit(serial8250_exit);
1240
1241 MODULE_LICENSE("GPL");
1242 MODULE_DESCRIPTION("Generic 8250/16x50 serial driver");
1243
1244 module_param_hw(share_irqs, uint, other, 0644);
1245 MODULE_PARM_DESC(share_irqs, "Share IRQs with other non-8250/16x50 devices (unsafe)");
1246
1247 module_param(nr_uarts, uint, 0644);
1248 MODULE_PARM_DESC(nr_uarts, "Maximum number of UARTs supported. (1-" __MODULE_STRING(CONFIG_SERIAL_8250_NR_UARTS) ")");
1249
1250 module_param(skip_txen_test, uint, 0644);
1251 MODULE_PARM_DESC(skip_txen_test, "Skip checking for the TXEN bug at init time");
1252
1253 #ifdef CONFIG_SERIAL_8250_RSA
1254 module_param_hw_array(probe_rsa, ulong, ioport, &probe_rsa_count, 0444);
1255 MODULE_PARM_DESC(probe_rsa, "Probe I/O ports for RSA");
1256 #endif
1257 MODULE_ALIAS_CHARDEV_MAJOR(TTY_MAJOR);
1258
1259 #ifdef CONFIG_SERIAL_8250_DEPRECATED_OPTIONS
1260 #ifndef MODULE
1261 /* This module was renamed to 8250_core in 3.7. Keep the old "8250" name
1262 * working as well for the module options so we don't break people. We
1263 * need to keep the names identical and the convenient macros will happily
1264 * refuse to let us do that by failing the build with redefinition errors
1265 * of global variables. So we stick them inside a dummy function to avoid
1266 * those conflicts. The options still get parsed, and the redefined
1267 * MODULE_PARAM_PREFIX lets us keep the "8250." syntax alive.
1268 *
1269 * This is hacky. I'm sorry.
1270 */
s8250_options(void)1271 static void __used s8250_options(void)
1272 {
1273 #undef MODULE_PARAM_PREFIX
1274 #define MODULE_PARAM_PREFIX "8250_core."
1275
1276 module_param_cb(share_irqs, ¶m_ops_uint, &share_irqs, 0644);
1277 module_param_cb(nr_uarts, ¶m_ops_uint, &nr_uarts, 0644);
1278 module_param_cb(skip_txen_test, ¶m_ops_uint, &skip_txen_test, 0644);
1279 #ifdef CONFIG_SERIAL_8250_RSA
1280 __module_param_call(MODULE_PARAM_PREFIX, probe_rsa,
1281 ¶m_array_ops, .arr = &__param_arr_probe_rsa,
1282 0444, -1, 0);
1283 #endif
1284 }
1285 #else
1286 MODULE_ALIAS("8250_core");
1287 #endif
1288 #endif
1289