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1// SPDX-License-Identifier: GPL-2.0-only
2/*
3 * Generic gameport layer
4 *
5 * Copyright (c) 1999-2002 Vojtech Pavlik
6 * Copyright (c) 2005 Dmitry Torokhov
7 */
8
9
10#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
11
12#include <linux/stddef.h>
13#include <linux/module.h>
14#include <linux/ioport.h>
15#include <linux/init.h>
16#include <linux/gameport.h>
17#include <linux/slab.h>
18#include <linux/delay.h>
19#include <linux/workqueue.h>
20#include <linux/sched.h> /* HZ */
21#include <linux/mutex.h>
22#include <linux/timekeeping.h>
23
24/*#include <asm/io.h>*/
25
26MODULE_AUTHOR("Vojtech Pavlik <vojtech@ucw.cz>");
27MODULE_DESCRIPTION("Generic gameport layer");
28MODULE_LICENSE("GPL");
29
30static bool use_ktime = true;
31module_param(use_ktime, bool, 0400);
32MODULE_PARM_DESC(use_ktime, "Use ktime for measuring I/O speed");
33
34/*
35 * gameport_mutex protects entire gameport subsystem and is taken
36 * every time gameport port or driver registrered or unregistered.
37 */
38static DEFINE_MUTEX(gameport_mutex);
39
40static LIST_HEAD(gameport_list);
41
42static struct bus_type gameport_bus;
43
44static void gameport_add_port(struct gameport *gameport);
45static void gameport_attach_driver(struct gameport_driver *drv);
46static void gameport_reconnect_port(struct gameport *gameport);
47static void gameport_disconnect_port(struct gameport *gameport);
48
49#if defined(__i386__)
50
51#include <linux/i8253.h>
52
53#define DELTA(x,y) ((y)-(x)+((y)<(x)?1193182/HZ:0))
54#define GET_TIME(x) do { x = get_time_pit(); } while (0)
55
56static unsigned int get_time_pit(void)
57{
58 unsigned long flags;
59 unsigned int count;
60
61 raw_spin_lock_irqsave(&i8253_lock, flags);
62 outb_p(0x00, 0x43);
63 count = inb_p(0x40);
64 count |= inb_p(0x40) << 8;
65 raw_spin_unlock_irqrestore(&i8253_lock, flags);
66
67 return count;
68}
69
70#endif
71
72
73
74/*
75 * gameport_measure_speed() measures the gameport i/o speed.
76 */
77
78static int gameport_measure_speed(struct gameport *gameport)
79{
80 unsigned int i, t, tx;
81 u64 t1, t2, t3;
82 unsigned long flags;
83
84 if (gameport_open(gameport, NULL, GAMEPORT_MODE_RAW))
85 return 0;
86
87 tx = ~0;
88
89 for (i = 0; i < 50; i++) {
90 local_irq_save(flags);
91 t1 = ktime_get_ns();
92 for (t = 0; t < 50; t++)
93 gameport_read(gameport);
94 t2 = ktime_get_ns();
95 t3 = ktime_get_ns();
96 local_irq_restore(flags);
97 udelay(i * 10);
98 t = (t2 - t1) - (t3 - t2);
99 if (t < tx)
100 tx = t;
101 }
102
103 gameport_close(gameport);
104 t = 1000000 * 50;
105 if (tx)
106 t /= tx;
107 return t;
108}
109
110static int old_gameport_measure_speed(struct gameport *gameport)
111{
112#if defined(__i386__)
113
114 unsigned int i, t, t1, t2, t3, tx;
115 unsigned long flags;
116
117 if (gameport_open(gameport, NULL, GAMEPORT_MODE_RAW))
118 return 0;
119
120 tx = 1 << 30;
121
122 for(i = 0; i < 50; i++) {
123 local_irq_save(flags);
124 GET_TIME(t1);
125 for (t = 0; t < 50; t++) gameport_read(gameport);
126 GET_TIME(t2);
127 GET_TIME(t3);
128 local_irq_restore(flags);
129 udelay(i * 10);
130 if ((t = DELTA(t2,t1) - DELTA(t3,t2)) < tx) tx = t;
131 }
132
133 gameport_close(gameport);
134 return 59659 / (tx < 1 ? 1 : tx);
135
136#elif defined (__x86_64__)
137
138 unsigned int i, t;
139 unsigned long tx, t1, t2, flags;
140
141 if (gameport_open(gameport, NULL, GAMEPORT_MODE_RAW))
142 return 0;
143
144 tx = 1 << 30;
145
146 for(i = 0; i < 50; i++) {
147 local_irq_save(flags);
148 t1 = rdtsc();
149 for (t = 0; t < 50; t++) gameport_read(gameport);
150 t2 = rdtsc();
151 local_irq_restore(flags);
152 udelay(i * 10);
153 if (t2 - t1 < tx) tx = t2 - t1;
154 }
155
156 gameport_close(gameport);
157 return (this_cpu_read(cpu_info.loops_per_jiffy) *
158 (unsigned long)HZ / (1000 / 50)) / (tx < 1 ? 1 : tx);
159
160#else
161
162 unsigned int j, t = 0;
163
164 if (gameport_open(gameport, NULL, GAMEPORT_MODE_RAW))
165 return 0;
166
167 j = jiffies; while (j == jiffies);
168 j = jiffies; while (j == jiffies) { t++; gameport_read(gameport); }
169
170 gameport_close(gameport);
171 return t * HZ / 1000;
172
173#endif
174}
175
176void gameport_start_polling(struct gameport *gameport)
177{
178 spin_lock(&gameport->timer_lock);
179
180 if (!gameport->poll_cnt++) {
181 BUG_ON(!gameport->poll_handler);
182 BUG_ON(!gameport->poll_interval);
183 mod_timer(&gameport->poll_timer, jiffies + msecs_to_jiffies(gameport->poll_interval));
184 }
185
186 spin_unlock(&gameport->timer_lock);
187}
188EXPORT_SYMBOL(gameport_start_polling);
189
190void gameport_stop_polling(struct gameport *gameport)
191{
192 spin_lock(&gameport->timer_lock);
193
194 if (!--gameport->poll_cnt)
195 del_timer(&gameport->poll_timer);
196
197 spin_unlock(&gameport->timer_lock);
198}
199EXPORT_SYMBOL(gameport_stop_polling);
200
201static void gameport_run_poll_handler(struct timer_list *t)
202{
203 struct gameport *gameport = from_timer(gameport, t, poll_timer);
204
205 gameport->poll_handler(gameport);
206 if (gameport->poll_cnt)
207 mod_timer(&gameport->poll_timer, jiffies + msecs_to_jiffies(gameport->poll_interval));
208}
209
210/*
211 * Basic gameport -> driver core mappings
212 */
213
214static int gameport_bind_driver(struct gameport *gameport, struct gameport_driver *drv)
215{
216 int error;
217
218 gameport->dev.driver = &drv->driver;
219 if (drv->connect(gameport, drv)) {
220 gameport->dev.driver = NULL;
221 return -ENODEV;
222 }
223
224 error = device_bind_driver(&gameport->dev);
225 if (error) {
226 dev_warn(&gameport->dev,
227 "device_bind_driver() failed for %s (%s) and %s, error: %d\n",
228 gameport->phys, gameport->name,
229 drv->description, error);
230 drv->disconnect(gameport);
231 gameport->dev.driver = NULL;
232 return error;
233 }
234
235 return 0;
236}
237
238static void gameport_find_driver(struct gameport *gameport)
239{
240 int error;
241
242 error = device_attach(&gameport->dev);
243 if (error < 0)
244 dev_warn(&gameport->dev,
245 "device_attach() failed for %s (%s), error: %d\n",
246 gameport->phys, gameport->name, error);
247}
248
249
250/*
251 * Gameport event processing.
252 */
253
254enum gameport_event_type {
255 GAMEPORT_REGISTER_PORT,
256 GAMEPORT_ATTACH_DRIVER,
257};
258
259struct gameport_event {
260 enum gameport_event_type type;
261 void *object;
262 struct module *owner;
263 struct list_head node;
264};
265
266static DEFINE_SPINLOCK(gameport_event_lock); /* protects gameport_event_list */
267static LIST_HEAD(gameport_event_list);
268
269static struct gameport_event *gameport_get_event(void)
270{
271 struct gameport_event *event = NULL;
272 unsigned long flags;
273
274 spin_lock_irqsave(&gameport_event_lock, flags);
275
276 if (!list_empty(&gameport_event_list)) {
277 event = list_first_entry(&gameport_event_list,
278 struct gameport_event, node);
279 list_del_init(&event->node);
280 }
281
282 spin_unlock_irqrestore(&gameport_event_lock, flags);
283 return event;
284}
285
286static void gameport_free_event(struct gameport_event *event)
287{
288 module_put(event->owner);
289 kfree(event);
290}
291
292static void gameport_remove_duplicate_events(struct gameport_event *event)
293{
294 struct gameport_event *e, *next;
295 unsigned long flags;
296
297 spin_lock_irqsave(&gameport_event_lock, flags);
298
299 list_for_each_entry_safe(e, next, &gameport_event_list, node) {
300 if (event->object == e->object) {
301 /*
302 * If this event is of different type we should not
303 * look further - we only suppress duplicate events
304 * that were sent back-to-back.
305 */
306 if (event->type != e->type)
307 break;
308
309 list_del_init(&e->node);
310 gameport_free_event(e);
311 }
312 }
313
314 spin_unlock_irqrestore(&gameport_event_lock, flags);
315}
316
317
318static void gameport_handle_events(struct work_struct *work)
319{
320 struct gameport_event *event;
321
322 mutex_lock(&gameport_mutex);
323
324 /*
325 * Note that we handle only one event here to give swsusp
326 * a chance to freeze kgameportd thread. Gameport events
327 * should be pretty rare so we are not concerned about
328 * taking performance hit.
329 */
330 if ((event = gameport_get_event())) {
331
332 switch (event->type) {
333
334 case GAMEPORT_REGISTER_PORT:
335 gameport_add_port(event->object);
336 break;
337
338 case GAMEPORT_ATTACH_DRIVER:
339 gameport_attach_driver(event->object);
340 break;
341 }
342
343 gameport_remove_duplicate_events(event);
344 gameport_free_event(event);
345 }
346
347 mutex_unlock(&gameport_mutex);
348}
349
350static DECLARE_WORK(gameport_event_work, gameport_handle_events);
351
352static int gameport_queue_event(void *object, struct module *owner,
353 enum gameport_event_type event_type)
354{
355 unsigned long flags;
356 struct gameport_event *event;
357 int retval = 0;
358
359 spin_lock_irqsave(&gameport_event_lock, flags);
360
361 /*
362 * Scan event list for the other events for the same gameport port,
363 * starting with the most recent one. If event is the same we
364 * do not need add new one. If event is of different type we
365 * need to add this event and should not look further because
366 * we need to preserve sequence of distinct events.
367 */
368 list_for_each_entry_reverse(event, &gameport_event_list, node) {
369 if (event->object == object) {
370 if (event->type == event_type)
371 goto out;
372 break;
373 }
374 }
375
376 event = kmalloc(sizeof(struct gameport_event), GFP_ATOMIC);
377 if (!event) {
378 pr_err("Not enough memory to queue event %d\n", event_type);
379 retval = -ENOMEM;
380 goto out;
381 }
382
383 if (!try_module_get(owner)) {
384 pr_warn("Can't get module reference, dropping event %d\n",
385 event_type);
386 kfree(event);
387 retval = -EINVAL;
388 goto out;
389 }
390
391 event->type = event_type;
392 event->object = object;
393 event->owner = owner;
394
395 list_add_tail(&event->node, &gameport_event_list);
396 queue_work(system_long_wq, &gameport_event_work);
397
398out:
399 spin_unlock_irqrestore(&gameport_event_lock, flags);
400 return retval;
401}
402
403/*
404 * Remove all events that have been submitted for a given object,
405 * be it a gameport port or a driver.
406 */
407static void gameport_remove_pending_events(void *object)
408{
409 struct gameport_event *event, *next;
410 unsigned long flags;
411
412 spin_lock_irqsave(&gameport_event_lock, flags);
413
414 list_for_each_entry_safe(event, next, &gameport_event_list, node) {
415 if (event->object == object) {
416 list_del_init(&event->node);
417 gameport_free_event(event);
418 }
419 }
420
421 spin_unlock_irqrestore(&gameport_event_lock, flags);
422}
423
424/*
425 * Destroy child gameport port (if any) that has not been fully registered yet.
426 *
427 * Note that we rely on the fact that port can have only one child and therefore
428 * only one child registration request can be pending. Additionally, children
429 * are registered by driver's connect() handler so there can't be a grandchild
430 * pending registration together with a child.
431 */
432static struct gameport *gameport_get_pending_child(struct gameport *parent)
433{
434 struct gameport_event *event;
435 struct gameport *gameport, *child = NULL;
436 unsigned long flags;
437
438 spin_lock_irqsave(&gameport_event_lock, flags);
439
440 list_for_each_entry(event, &gameport_event_list, node) {
441 if (event->type == GAMEPORT_REGISTER_PORT) {
442 gameport = event->object;
443 if (gameport->parent == parent) {
444 child = gameport;
445 break;
446 }
447 }
448 }
449
450 spin_unlock_irqrestore(&gameport_event_lock, flags);
451 return child;
452}
453
454/*
455 * Gameport port operations
456 */
457
458static ssize_t gameport_description_show(struct device *dev, struct device_attribute *attr, char *buf)
459{
460 struct gameport *gameport = to_gameport_port(dev);
461
462 return sprintf(buf, "%s\n", gameport->name);
463}
464static DEVICE_ATTR(description, S_IRUGO, gameport_description_show, NULL);
465
466static ssize_t drvctl_store(struct device *dev, struct device_attribute *attr, const char *buf, size_t count)
467{
468 struct gameport *gameport = to_gameport_port(dev);
469 struct device_driver *drv;
470 int error;
471
472 error = mutex_lock_interruptible(&gameport_mutex);
473 if (error)
474 return error;
475
476 if (!strncmp(buf, "none", count)) {
477 gameport_disconnect_port(gameport);
478 } else if (!strncmp(buf, "reconnect", count)) {
479 gameport_reconnect_port(gameport);
480 } else if (!strncmp(buf, "rescan", count)) {
481 gameport_disconnect_port(gameport);
482 gameport_find_driver(gameport);
483 } else if ((drv = driver_find(buf, &gameport_bus)) != NULL) {
484 gameport_disconnect_port(gameport);
485 error = gameport_bind_driver(gameport, to_gameport_driver(drv));
486 } else {
487 error = -EINVAL;
488 }
489
490 mutex_unlock(&gameport_mutex);
491
492 return error ? error : count;
493}
494static DEVICE_ATTR_WO(drvctl);
495
496static struct attribute *gameport_device_attrs[] = {
497 &dev_attr_description.attr,
498 &dev_attr_drvctl.attr,
499 NULL,
500};
501ATTRIBUTE_GROUPS(gameport_device);
502
503static void gameport_release_port(struct device *dev)
504{
505 struct gameport *gameport = to_gameport_port(dev);
506
507 kfree(gameport);
508 module_put(THIS_MODULE);
509}
510
511void gameport_set_phys(struct gameport *gameport, const char *fmt, ...)
512{
513 va_list args;
514
515 va_start(args, fmt);
516 vsnprintf(gameport->phys, sizeof(gameport->phys), fmt, args);
517 va_end(args);
518}
519EXPORT_SYMBOL(gameport_set_phys);
520
521/*
522 * Prepare gameport port for registration.
523 */
524static void gameport_init_port(struct gameport *gameport)
525{
526 static atomic_t gameport_no = ATOMIC_INIT(-1);
527
528 __module_get(THIS_MODULE);
529
530 mutex_init(&gameport->drv_mutex);
531 device_initialize(&gameport->dev);
532 dev_set_name(&gameport->dev, "gameport%lu",
533 (unsigned long)atomic_inc_return(&gameport_no));
534 gameport->dev.bus = &gameport_bus;
535 gameport->dev.release = gameport_release_port;
536 if (gameport->parent)
537 gameport->dev.parent = &gameport->parent->dev;
538
539 INIT_LIST_HEAD(&gameport->node);
540 spin_lock_init(&gameport->timer_lock);
541 timer_setup(&gameport->poll_timer, gameport_run_poll_handler, 0);
542}
543
544/*
545 * Complete gameport port registration.
546 * Driver core will attempt to find appropriate driver for the port.
547 */
548static void gameport_add_port(struct gameport *gameport)
549{
550 int error;
551
552 if (gameport->parent)
553 gameport->parent->child = gameport;
554
555 gameport->speed = use_ktime ?
556 gameport_measure_speed(gameport) :
557 old_gameport_measure_speed(gameport);
558
559 list_add_tail(&gameport->node, &gameport_list);
560
561 if (gameport->io)
562 dev_info(&gameport->dev, "%s is %s, io %#x, speed %dkHz\n",
563 gameport->name, gameport->phys, gameport->io, gameport->speed);
564 else
565 dev_info(&gameport->dev, "%s is %s, speed %dkHz\n",
566 gameport->name, gameport->phys, gameport->speed);
567
568 error = device_add(&gameport->dev);
569 if (error)
570 dev_err(&gameport->dev,
571 "device_add() failed for %s (%s), error: %d\n",
572 gameport->phys, gameport->name, error);
573}
574
575/*
576 * gameport_destroy_port() completes deregistration process and removes
577 * port from the system
578 */
579static void gameport_destroy_port(struct gameport *gameport)
580{
581 struct gameport *child;
582
583 child = gameport_get_pending_child(gameport);
584 if (child) {
585 gameport_remove_pending_events(child);
586 put_device(&child->dev);
587 }
588
589 if (gameport->parent) {
590 gameport->parent->child = NULL;
591 gameport->parent = NULL;
592 }
593
594 if (device_is_registered(&gameport->dev))
595 device_del(&gameport->dev);
596
597 list_del_init(&gameport->node);
598
599 gameport_remove_pending_events(gameport);
600 put_device(&gameport->dev);
601}
602
603/*
604 * Reconnect gameport port and all its children (re-initialize attached devices)
605 */
606static void gameport_reconnect_port(struct gameport *gameport)
607{
608 do {
609 if (!gameport->drv || !gameport->drv->reconnect || gameport->drv->reconnect(gameport)) {
610 gameport_disconnect_port(gameport);
611 gameport_find_driver(gameport);
612 /* Ok, old children are now gone, we are done */
613 break;
614 }
615 gameport = gameport->child;
616 } while (gameport);
617}
618
619/*
620 * gameport_disconnect_port() unbinds a port from its driver. As a side effect
621 * all child ports are unbound and destroyed.
622 */
623static void gameport_disconnect_port(struct gameport *gameport)
624{
625 struct gameport *s, *parent;
626
627 if (gameport->child) {
628 /*
629 * Children ports should be disconnected and destroyed
630 * first, staring with the leaf one, since we don't want
631 * to do recursion
632 */
633 for (s = gameport; s->child; s = s->child)
634 /* empty */;
635
636 do {
637 parent = s->parent;
638
639 device_release_driver(&s->dev);
640 gameport_destroy_port(s);
641 } while ((s = parent) != gameport);
642 }
643
644 /*
645 * Ok, no children left, now disconnect this port
646 */
647 device_release_driver(&gameport->dev);
648}
649
650/*
651 * Submits register request to kgameportd for subsequent execution.
652 * Note that port registration is always asynchronous.
653 */
654void __gameport_register_port(struct gameport *gameport, struct module *owner)
655{
656 gameport_init_port(gameport);
657 gameport_queue_event(gameport, owner, GAMEPORT_REGISTER_PORT);
658}
659EXPORT_SYMBOL(__gameport_register_port);
660
661/*
662 * Synchronously unregisters gameport port.
663 */
664void gameport_unregister_port(struct gameport *gameport)
665{
666 mutex_lock(&gameport_mutex);
667 gameport_disconnect_port(gameport);
668 gameport_destroy_port(gameport);
669 mutex_unlock(&gameport_mutex);
670}
671EXPORT_SYMBOL(gameport_unregister_port);
672
673
674/*
675 * Gameport driver operations
676 */
677
678static ssize_t description_show(struct device_driver *drv, char *buf)
679{
680 struct gameport_driver *driver = to_gameport_driver(drv);
681 return sprintf(buf, "%s\n", driver->description ? driver->description : "(none)");
682}
683static DRIVER_ATTR_RO(description);
684
685static struct attribute *gameport_driver_attrs[] = {
686 &driver_attr_description.attr,
687 NULL
688};
689ATTRIBUTE_GROUPS(gameport_driver);
690
691static int gameport_driver_probe(struct device *dev)
692{
693 struct gameport *gameport = to_gameport_port(dev);
694 struct gameport_driver *drv = to_gameport_driver(dev->driver);
695
696 drv->connect(gameport, drv);
697 return gameport->drv ? 0 : -ENODEV;
698}
699
700static int gameport_driver_remove(struct device *dev)
701{
702 struct gameport *gameport = to_gameport_port(dev);
703 struct gameport_driver *drv = to_gameport_driver(dev->driver);
704
705 drv->disconnect(gameport);
706 return 0;
707}
708
709static void gameport_attach_driver(struct gameport_driver *drv)
710{
711 int error;
712
713 error = driver_attach(&drv->driver);
714 if (error)
715 pr_err("driver_attach() failed for %s, error: %d\n",
716 drv->driver.name, error);
717}
718
719int __gameport_register_driver(struct gameport_driver *drv, struct module *owner,
720 const char *mod_name)
721{
722 int error;
723
724 drv->driver.bus = &gameport_bus;
725 drv->driver.owner = owner;
726 drv->driver.mod_name = mod_name;
727
728 /*
729 * Temporarily disable automatic binding because probing
730 * takes long time and we are better off doing it in kgameportd
731 */
732 drv->ignore = true;
733
734 error = driver_register(&drv->driver);
735 if (error) {
736 pr_err("driver_register() failed for %s, error: %d\n",
737 drv->driver.name, error);
738 return error;
739 }
740
741 /*
742 * Reset ignore flag and let kgameportd bind the driver to free ports
743 */
744 drv->ignore = false;
745 error = gameport_queue_event(drv, NULL, GAMEPORT_ATTACH_DRIVER);
746 if (error) {
747 driver_unregister(&drv->driver);
748 return error;
749 }
750
751 return 0;
752}
753EXPORT_SYMBOL(__gameport_register_driver);
754
755void gameport_unregister_driver(struct gameport_driver *drv)
756{
757 struct gameport *gameport;
758
759 mutex_lock(&gameport_mutex);
760
761 drv->ignore = true; /* so gameport_find_driver ignores it */
762 gameport_remove_pending_events(drv);
763
764start_over:
765 list_for_each_entry(gameport, &gameport_list, node) {
766 if (gameport->drv == drv) {
767 gameport_disconnect_port(gameport);
768 gameport_find_driver(gameport);
769 /* we could've deleted some ports, restart */
770 goto start_over;
771 }
772 }
773
774 driver_unregister(&drv->driver);
775
776 mutex_unlock(&gameport_mutex);
777}
778EXPORT_SYMBOL(gameport_unregister_driver);
779
780static int gameport_bus_match(struct device *dev, struct device_driver *drv)
781{
782 struct gameport_driver *gameport_drv = to_gameport_driver(drv);
783
784 return !gameport_drv->ignore;
785}
786
787static struct bus_type gameport_bus = {
788 .name = "gameport",
789 .dev_groups = gameport_device_groups,
790 .drv_groups = gameport_driver_groups,
791 .match = gameport_bus_match,
792 .probe = gameport_driver_probe,
793 .remove = gameport_driver_remove,
794};
795
796static void gameport_set_drv(struct gameport *gameport, struct gameport_driver *drv)
797{
798 mutex_lock(&gameport->drv_mutex);
799 gameport->drv = drv;
800 mutex_unlock(&gameport->drv_mutex);
801}
802
803int gameport_open(struct gameport *gameport, struct gameport_driver *drv, int mode)
804{
805 if (gameport->open) {
806 if (gameport->open(gameport, mode)) {
807 return -1;
808 }
809 } else {
810 if (mode != GAMEPORT_MODE_RAW)
811 return -1;
812 }
813
814 gameport_set_drv(gameport, drv);
815 return 0;
816}
817EXPORT_SYMBOL(gameport_open);
818
819void gameport_close(struct gameport *gameport)
820{
821 del_timer_sync(&gameport->poll_timer);
822 gameport->poll_handler = NULL;
823 gameport->poll_interval = 0;
824 gameport_set_drv(gameport, NULL);
825 if (gameport->close)
826 gameport->close(gameport);
827}
828EXPORT_SYMBOL(gameport_close);
829
830static int __init gameport_init(void)
831{
832 int error;
833
834 error = bus_register(&gameport_bus);
835 if (error) {
836 pr_err("failed to register gameport bus, error: %d\n", error);
837 return error;
838 }
839
840
841 return 0;
842}
843
844static void __exit gameport_exit(void)
845{
846 bus_unregister(&gameport_bus);
847
848 /*
849 * There should not be any outstanding events but work may
850 * still be scheduled so simply cancel it.
851 */
852 cancel_work_sync(&gameport_event_work);
853}
854
855subsys_initcall(gameport_init);
856module_exit(gameport_exit);
1/*
2 * Generic gameport layer
3 *
4 * Copyright (c) 1999-2002 Vojtech Pavlik
5 * Copyright (c) 2005 Dmitry Torokhov
6 */
7
8/*
9 * This program is free software; you can redistribute it and/or modify it
10 * under the terms of the GNU General Public License version 2 as published by
11 * the Free Software Foundation.
12 */
13
14#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
15
16#include <linux/stddef.h>
17#include <linux/module.h>
18#include <linux/ioport.h>
19#include <linux/init.h>
20#include <linux/gameport.h>
21#include <linux/slab.h>
22#include <linux/delay.h>
23#include <linux/workqueue.h>
24#include <linux/sched.h> /* HZ */
25#include <linux/mutex.h>
26#include <linux/timekeeping.h>
27
28/*#include <asm/io.h>*/
29
30MODULE_AUTHOR("Vojtech Pavlik <vojtech@ucw.cz>");
31MODULE_DESCRIPTION("Generic gameport layer");
32MODULE_LICENSE("GPL");
33
34static bool use_ktime = true;
35module_param(use_ktime, bool, 0400);
36MODULE_PARM_DESC(use_ktime, "Use ktime for measuring I/O speed");
37
38/*
39 * gameport_mutex protects entire gameport subsystem and is taken
40 * every time gameport port or driver registrered or unregistered.
41 */
42static DEFINE_MUTEX(gameport_mutex);
43
44static LIST_HEAD(gameport_list);
45
46static struct bus_type gameport_bus;
47
48static void gameport_add_port(struct gameport *gameport);
49static void gameport_attach_driver(struct gameport_driver *drv);
50static void gameport_reconnect_port(struct gameport *gameport);
51static void gameport_disconnect_port(struct gameport *gameport);
52
53#if defined(__i386__)
54
55#include <linux/i8253.h>
56
57#define DELTA(x,y) ((y)-(x)+((y)<(x)?1193182/HZ:0))
58#define GET_TIME(x) do { x = get_time_pit(); } while (0)
59
60static unsigned int get_time_pit(void)
61{
62 unsigned long flags;
63 unsigned int count;
64
65 raw_spin_lock_irqsave(&i8253_lock, flags);
66 outb_p(0x00, 0x43);
67 count = inb_p(0x40);
68 count |= inb_p(0x40) << 8;
69 raw_spin_unlock_irqrestore(&i8253_lock, flags);
70
71 return count;
72}
73
74#endif
75
76
77
78/*
79 * gameport_measure_speed() measures the gameport i/o speed.
80 */
81
82static int gameport_measure_speed(struct gameport *gameport)
83{
84 unsigned int i, t, tx;
85 u64 t1, t2, t3;
86 unsigned long flags;
87
88 if (gameport_open(gameport, NULL, GAMEPORT_MODE_RAW))
89 return 0;
90
91 tx = ~0;
92
93 for (i = 0; i < 50; i++) {
94 local_irq_save(flags);
95 t1 = ktime_get_ns();
96 for (t = 0; t < 50; t++)
97 gameport_read(gameport);
98 t2 = ktime_get_ns();
99 t3 = ktime_get_ns();
100 local_irq_restore(flags);
101 udelay(i * 10);
102 t = (t2 - t1) - (t3 - t2);
103 if (t < tx)
104 tx = t;
105 }
106
107 gameport_close(gameport);
108 t = 1000000 * 50;
109 if (tx)
110 t /= tx;
111 return t;
112}
113
114static int old_gameport_measure_speed(struct gameport *gameport)
115{
116#if defined(__i386__)
117
118 unsigned int i, t, t1, t2, t3, tx;
119 unsigned long flags;
120
121 if (gameport_open(gameport, NULL, GAMEPORT_MODE_RAW))
122 return 0;
123
124 tx = 1 << 30;
125
126 for(i = 0; i < 50; i++) {
127 local_irq_save(flags);
128 GET_TIME(t1);
129 for (t = 0; t < 50; t++) gameport_read(gameport);
130 GET_TIME(t2);
131 GET_TIME(t3);
132 local_irq_restore(flags);
133 udelay(i * 10);
134 if ((t = DELTA(t2,t1) - DELTA(t3,t2)) < tx) tx = t;
135 }
136
137 gameport_close(gameport);
138 return 59659 / (tx < 1 ? 1 : tx);
139
140#elif defined (__x86_64__)
141
142 unsigned int i, t;
143 unsigned long tx, t1, t2, flags;
144
145 if (gameport_open(gameport, NULL, GAMEPORT_MODE_RAW))
146 return 0;
147
148 tx = 1 << 30;
149
150 for(i = 0; i < 50; i++) {
151 local_irq_save(flags);
152 t1 = rdtsc();
153 for (t = 0; t < 50; t++) gameport_read(gameport);
154 t2 = rdtsc();
155 local_irq_restore(flags);
156 udelay(i * 10);
157 if (t2 - t1 < tx) tx = t2 - t1;
158 }
159
160 gameport_close(gameport);
161 return (this_cpu_read(cpu_info.loops_per_jiffy) *
162 (unsigned long)HZ / (1000 / 50)) / (tx < 1 ? 1 : tx);
163
164#else
165
166 unsigned int j, t = 0;
167
168 if (gameport_open(gameport, NULL, GAMEPORT_MODE_RAW))
169 return 0;
170
171 j = jiffies; while (j == jiffies);
172 j = jiffies; while (j == jiffies) { t++; gameport_read(gameport); }
173
174 gameport_close(gameport);
175 return t * HZ / 1000;
176
177#endif
178}
179
180void gameport_start_polling(struct gameport *gameport)
181{
182 spin_lock(&gameport->timer_lock);
183
184 if (!gameport->poll_cnt++) {
185 BUG_ON(!gameport->poll_handler);
186 BUG_ON(!gameport->poll_interval);
187 mod_timer(&gameport->poll_timer, jiffies + msecs_to_jiffies(gameport->poll_interval));
188 }
189
190 spin_unlock(&gameport->timer_lock);
191}
192EXPORT_SYMBOL(gameport_start_polling);
193
194void gameport_stop_polling(struct gameport *gameport)
195{
196 spin_lock(&gameport->timer_lock);
197
198 if (!--gameport->poll_cnt)
199 del_timer(&gameport->poll_timer);
200
201 spin_unlock(&gameport->timer_lock);
202}
203EXPORT_SYMBOL(gameport_stop_polling);
204
205static void gameport_run_poll_handler(unsigned long d)
206{
207 struct gameport *gameport = (struct gameport *)d;
208
209 gameport->poll_handler(gameport);
210 if (gameport->poll_cnt)
211 mod_timer(&gameport->poll_timer, jiffies + msecs_to_jiffies(gameport->poll_interval));
212}
213
214/*
215 * Basic gameport -> driver core mappings
216 */
217
218static int gameport_bind_driver(struct gameport *gameport, struct gameport_driver *drv)
219{
220 int error;
221
222 gameport->dev.driver = &drv->driver;
223 if (drv->connect(gameport, drv)) {
224 gameport->dev.driver = NULL;
225 return -ENODEV;
226 }
227
228 error = device_bind_driver(&gameport->dev);
229 if (error) {
230 dev_warn(&gameport->dev,
231 "device_bind_driver() failed for %s (%s) and %s, error: %d\n",
232 gameport->phys, gameport->name,
233 drv->description, error);
234 drv->disconnect(gameport);
235 gameport->dev.driver = NULL;
236 return error;
237 }
238
239 return 0;
240}
241
242static void gameport_find_driver(struct gameport *gameport)
243{
244 int error;
245
246 error = device_attach(&gameport->dev);
247 if (error < 0)
248 dev_warn(&gameport->dev,
249 "device_attach() failed for %s (%s), error: %d\n",
250 gameport->phys, gameport->name, error);
251}
252
253
254/*
255 * Gameport event processing.
256 */
257
258enum gameport_event_type {
259 GAMEPORT_REGISTER_PORT,
260 GAMEPORT_ATTACH_DRIVER,
261};
262
263struct gameport_event {
264 enum gameport_event_type type;
265 void *object;
266 struct module *owner;
267 struct list_head node;
268};
269
270static DEFINE_SPINLOCK(gameport_event_lock); /* protects gameport_event_list */
271static LIST_HEAD(gameport_event_list);
272
273static struct gameport_event *gameport_get_event(void)
274{
275 struct gameport_event *event = NULL;
276 unsigned long flags;
277
278 spin_lock_irqsave(&gameport_event_lock, flags);
279
280 if (!list_empty(&gameport_event_list)) {
281 event = list_first_entry(&gameport_event_list,
282 struct gameport_event, node);
283 list_del_init(&event->node);
284 }
285
286 spin_unlock_irqrestore(&gameport_event_lock, flags);
287 return event;
288}
289
290static void gameport_free_event(struct gameport_event *event)
291{
292 module_put(event->owner);
293 kfree(event);
294}
295
296static void gameport_remove_duplicate_events(struct gameport_event *event)
297{
298 struct gameport_event *e, *next;
299 unsigned long flags;
300
301 spin_lock_irqsave(&gameport_event_lock, flags);
302
303 list_for_each_entry_safe(e, next, &gameport_event_list, node) {
304 if (event->object == e->object) {
305 /*
306 * If this event is of different type we should not
307 * look further - we only suppress duplicate events
308 * that were sent back-to-back.
309 */
310 if (event->type != e->type)
311 break;
312
313 list_del_init(&e->node);
314 gameport_free_event(e);
315 }
316 }
317
318 spin_unlock_irqrestore(&gameport_event_lock, flags);
319}
320
321
322static void gameport_handle_events(struct work_struct *work)
323{
324 struct gameport_event *event;
325
326 mutex_lock(&gameport_mutex);
327
328 /*
329 * Note that we handle only one event here to give swsusp
330 * a chance to freeze kgameportd thread. Gameport events
331 * should be pretty rare so we are not concerned about
332 * taking performance hit.
333 */
334 if ((event = gameport_get_event())) {
335
336 switch (event->type) {
337
338 case GAMEPORT_REGISTER_PORT:
339 gameport_add_port(event->object);
340 break;
341
342 case GAMEPORT_ATTACH_DRIVER:
343 gameport_attach_driver(event->object);
344 break;
345 }
346
347 gameport_remove_duplicate_events(event);
348 gameport_free_event(event);
349 }
350
351 mutex_unlock(&gameport_mutex);
352}
353
354static DECLARE_WORK(gameport_event_work, gameport_handle_events);
355
356static int gameport_queue_event(void *object, struct module *owner,
357 enum gameport_event_type event_type)
358{
359 unsigned long flags;
360 struct gameport_event *event;
361 int retval = 0;
362
363 spin_lock_irqsave(&gameport_event_lock, flags);
364
365 /*
366 * Scan event list for the other events for the same gameport port,
367 * starting with the most recent one. If event is the same we
368 * do not need add new one. If event is of different type we
369 * need to add this event and should not look further because
370 * we need to preserve sequence of distinct events.
371 */
372 list_for_each_entry_reverse(event, &gameport_event_list, node) {
373 if (event->object == object) {
374 if (event->type == event_type)
375 goto out;
376 break;
377 }
378 }
379
380 event = kmalloc(sizeof(struct gameport_event), GFP_ATOMIC);
381 if (!event) {
382 pr_err("Not enough memory to queue event %d\n", event_type);
383 retval = -ENOMEM;
384 goto out;
385 }
386
387 if (!try_module_get(owner)) {
388 pr_warning("Can't get module reference, dropping event %d\n",
389 event_type);
390 kfree(event);
391 retval = -EINVAL;
392 goto out;
393 }
394
395 event->type = event_type;
396 event->object = object;
397 event->owner = owner;
398
399 list_add_tail(&event->node, &gameport_event_list);
400 queue_work(system_long_wq, &gameport_event_work);
401
402out:
403 spin_unlock_irqrestore(&gameport_event_lock, flags);
404 return retval;
405}
406
407/*
408 * Remove all events that have been submitted for a given object,
409 * be it a gameport port or a driver.
410 */
411static void gameport_remove_pending_events(void *object)
412{
413 struct gameport_event *event, *next;
414 unsigned long flags;
415
416 spin_lock_irqsave(&gameport_event_lock, flags);
417
418 list_for_each_entry_safe(event, next, &gameport_event_list, node) {
419 if (event->object == object) {
420 list_del_init(&event->node);
421 gameport_free_event(event);
422 }
423 }
424
425 spin_unlock_irqrestore(&gameport_event_lock, flags);
426}
427
428/*
429 * Destroy child gameport port (if any) that has not been fully registered yet.
430 *
431 * Note that we rely on the fact that port can have only one child and therefore
432 * only one child registration request can be pending. Additionally, children
433 * are registered by driver's connect() handler so there can't be a grandchild
434 * pending registration together with a child.
435 */
436static struct gameport *gameport_get_pending_child(struct gameport *parent)
437{
438 struct gameport_event *event;
439 struct gameport *gameport, *child = NULL;
440 unsigned long flags;
441
442 spin_lock_irqsave(&gameport_event_lock, flags);
443
444 list_for_each_entry(event, &gameport_event_list, node) {
445 if (event->type == GAMEPORT_REGISTER_PORT) {
446 gameport = event->object;
447 if (gameport->parent == parent) {
448 child = gameport;
449 break;
450 }
451 }
452 }
453
454 spin_unlock_irqrestore(&gameport_event_lock, flags);
455 return child;
456}
457
458/*
459 * Gameport port operations
460 */
461
462static ssize_t gameport_description_show(struct device *dev, struct device_attribute *attr, char *buf)
463{
464 struct gameport *gameport = to_gameport_port(dev);
465
466 return sprintf(buf, "%s\n", gameport->name);
467}
468static DEVICE_ATTR(description, S_IRUGO, gameport_description_show, NULL);
469
470static ssize_t drvctl_store(struct device *dev, struct device_attribute *attr, const char *buf, size_t count)
471{
472 struct gameport *gameport = to_gameport_port(dev);
473 struct device_driver *drv;
474 int error;
475
476 error = mutex_lock_interruptible(&gameport_mutex);
477 if (error)
478 return error;
479
480 if (!strncmp(buf, "none", count)) {
481 gameport_disconnect_port(gameport);
482 } else if (!strncmp(buf, "reconnect", count)) {
483 gameport_reconnect_port(gameport);
484 } else if (!strncmp(buf, "rescan", count)) {
485 gameport_disconnect_port(gameport);
486 gameport_find_driver(gameport);
487 } else if ((drv = driver_find(buf, &gameport_bus)) != NULL) {
488 gameport_disconnect_port(gameport);
489 error = gameport_bind_driver(gameport, to_gameport_driver(drv));
490 } else {
491 error = -EINVAL;
492 }
493
494 mutex_unlock(&gameport_mutex);
495
496 return error ? error : count;
497}
498static DEVICE_ATTR_WO(drvctl);
499
500static struct attribute *gameport_device_attrs[] = {
501 &dev_attr_description.attr,
502 &dev_attr_drvctl.attr,
503 NULL,
504};
505ATTRIBUTE_GROUPS(gameport_device);
506
507static void gameport_release_port(struct device *dev)
508{
509 struct gameport *gameport = to_gameport_port(dev);
510
511 kfree(gameport);
512 module_put(THIS_MODULE);
513}
514
515void gameport_set_phys(struct gameport *gameport, const char *fmt, ...)
516{
517 va_list args;
518
519 va_start(args, fmt);
520 vsnprintf(gameport->phys, sizeof(gameport->phys), fmt, args);
521 va_end(args);
522}
523EXPORT_SYMBOL(gameport_set_phys);
524
525/*
526 * Prepare gameport port for registration.
527 */
528static void gameport_init_port(struct gameport *gameport)
529{
530 static atomic_t gameport_no = ATOMIC_INIT(-1);
531
532 __module_get(THIS_MODULE);
533
534 mutex_init(&gameport->drv_mutex);
535 device_initialize(&gameport->dev);
536 dev_set_name(&gameport->dev, "gameport%lu",
537 (unsigned long)atomic_inc_return(&gameport_no));
538 gameport->dev.bus = &gameport_bus;
539 gameport->dev.release = gameport_release_port;
540 if (gameport->parent)
541 gameport->dev.parent = &gameport->parent->dev;
542
543 INIT_LIST_HEAD(&gameport->node);
544 spin_lock_init(&gameport->timer_lock);
545 init_timer(&gameport->poll_timer);
546 gameport->poll_timer.function = gameport_run_poll_handler;
547 gameport->poll_timer.data = (unsigned long)gameport;
548}
549
550/*
551 * Complete gameport port registration.
552 * Driver core will attempt to find appropriate driver for the port.
553 */
554static void gameport_add_port(struct gameport *gameport)
555{
556 int error;
557
558 if (gameport->parent)
559 gameport->parent->child = gameport;
560
561 gameport->speed = use_ktime ?
562 gameport_measure_speed(gameport) :
563 old_gameport_measure_speed(gameport);
564
565 list_add_tail(&gameport->node, &gameport_list);
566
567 if (gameport->io)
568 dev_info(&gameport->dev, "%s is %s, io %#x, speed %dkHz\n",
569 gameport->name, gameport->phys, gameport->io, gameport->speed);
570 else
571 dev_info(&gameport->dev, "%s is %s, speed %dkHz\n",
572 gameport->name, gameport->phys, gameport->speed);
573
574 error = device_add(&gameport->dev);
575 if (error)
576 dev_err(&gameport->dev,
577 "device_add() failed for %s (%s), error: %d\n",
578 gameport->phys, gameport->name, error);
579}
580
581/*
582 * gameport_destroy_port() completes deregistration process and removes
583 * port from the system
584 */
585static void gameport_destroy_port(struct gameport *gameport)
586{
587 struct gameport *child;
588
589 child = gameport_get_pending_child(gameport);
590 if (child) {
591 gameport_remove_pending_events(child);
592 put_device(&child->dev);
593 }
594
595 if (gameport->parent) {
596 gameport->parent->child = NULL;
597 gameport->parent = NULL;
598 }
599
600 if (device_is_registered(&gameport->dev))
601 device_del(&gameport->dev);
602
603 list_del_init(&gameport->node);
604
605 gameport_remove_pending_events(gameport);
606 put_device(&gameport->dev);
607}
608
609/*
610 * Reconnect gameport port and all its children (re-initialize attached devices)
611 */
612static void gameport_reconnect_port(struct gameport *gameport)
613{
614 do {
615 if (!gameport->drv || !gameport->drv->reconnect || gameport->drv->reconnect(gameport)) {
616 gameport_disconnect_port(gameport);
617 gameport_find_driver(gameport);
618 /* Ok, old children are now gone, we are done */
619 break;
620 }
621 gameport = gameport->child;
622 } while (gameport);
623}
624
625/*
626 * gameport_disconnect_port() unbinds a port from its driver. As a side effect
627 * all child ports are unbound and destroyed.
628 */
629static void gameport_disconnect_port(struct gameport *gameport)
630{
631 struct gameport *s, *parent;
632
633 if (gameport->child) {
634 /*
635 * Children ports should be disconnected and destroyed
636 * first, staring with the leaf one, since we don't want
637 * to do recursion
638 */
639 for (s = gameport; s->child; s = s->child)
640 /* empty */;
641
642 do {
643 parent = s->parent;
644
645 device_release_driver(&s->dev);
646 gameport_destroy_port(s);
647 } while ((s = parent) != gameport);
648 }
649
650 /*
651 * Ok, no children left, now disconnect this port
652 */
653 device_release_driver(&gameport->dev);
654}
655
656/*
657 * Submits register request to kgameportd for subsequent execution.
658 * Note that port registration is always asynchronous.
659 */
660void __gameport_register_port(struct gameport *gameport, struct module *owner)
661{
662 gameport_init_port(gameport);
663 gameport_queue_event(gameport, owner, GAMEPORT_REGISTER_PORT);
664}
665EXPORT_SYMBOL(__gameport_register_port);
666
667/*
668 * Synchronously unregisters gameport port.
669 */
670void gameport_unregister_port(struct gameport *gameport)
671{
672 mutex_lock(&gameport_mutex);
673 gameport_disconnect_port(gameport);
674 gameport_destroy_port(gameport);
675 mutex_unlock(&gameport_mutex);
676}
677EXPORT_SYMBOL(gameport_unregister_port);
678
679
680/*
681 * Gameport driver operations
682 */
683
684static ssize_t description_show(struct device_driver *drv, char *buf)
685{
686 struct gameport_driver *driver = to_gameport_driver(drv);
687 return sprintf(buf, "%s\n", driver->description ? driver->description : "(none)");
688}
689static DRIVER_ATTR_RO(description);
690
691static struct attribute *gameport_driver_attrs[] = {
692 &driver_attr_description.attr,
693 NULL
694};
695ATTRIBUTE_GROUPS(gameport_driver);
696
697static int gameport_driver_probe(struct device *dev)
698{
699 struct gameport *gameport = to_gameport_port(dev);
700 struct gameport_driver *drv = to_gameport_driver(dev->driver);
701
702 drv->connect(gameport, drv);
703 return gameport->drv ? 0 : -ENODEV;
704}
705
706static int gameport_driver_remove(struct device *dev)
707{
708 struct gameport *gameport = to_gameport_port(dev);
709 struct gameport_driver *drv = to_gameport_driver(dev->driver);
710
711 drv->disconnect(gameport);
712 return 0;
713}
714
715static void gameport_attach_driver(struct gameport_driver *drv)
716{
717 int error;
718
719 error = driver_attach(&drv->driver);
720 if (error)
721 pr_err("driver_attach() failed for %s, error: %d\n",
722 drv->driver.name, error);
723}
724
725int __gameport_register_driver(struct gameport_driver *drv, struct module *owner,
726 const char *mod_name)
727{
728 int error;
729
730 drv->driver.bus = &gameport_bus;
731 drv->driver.owner = owner;
732 drv->driver.mod_name = mod_name;
733
734 /*
735 * Temporarily disable automatic binding because probing
736 * takes long time and we are better off doing it in kgameportd
737 */
738 drv->ignore = true;
739
740 error = driver_register(&drv->driver);
741 if (error) {
742 pr_err("driver_register() failed for %s, error: %d\n",
743 drv->driver.name, error);
744 return error;
745 }
746
747 /*
748 * Reset ignore flag and let kgameportd bind the driver to free ports
749 */
750 drv->ignore = false;
751 error = gameport_queue_event(drv, NULL, GAMEPORT_ATTACH_DRIVER);
752 if (error) {
753 driver_unregister(&drv->driver);
754 return error;
755 }
756
757 return 0;
758}
759EXPORT_SYMBOL(__gameport_register_driver);
760
761void gameport_unregister_driver(struct gameport_driver *drv)
762{
763 struct gameport *gameport;
764
765 mutex_lock(&gameport_mutex);
766
767 drv->ignore = true; /* so gameport_find_driver ignores it */
768 gameport_remove_pending_events(drv);
769
770start_over:
771 list_for_each_entry(gameport, &gameport_list, node) {
772 if (gameport->drv == drv) {
773 gameport_disconnect_port(gameport);
774 gameport_find_driver(gameport);
775 /* we could've deleted some ports, restart */
776 goto start_over;
777 }
778 }
779
780 driver_unregister(&drv->driver);
781
782 mutex_unlock(&gameport_mutex);
783}
784EXPORT_SYMBOL(gameport_unregister_driver);
785
786static int gameport_bus_match(struct device *dev, struct device_driver *drv)
787{
788 struct gameport_driver *gameport_drv = to_gameport_driver(drv);
789
790 return !gameport_drv->ignore;
791}
792
793static struct bus_type gameport_bus = {
794 .name = "gameport",
795 .dev_groups = gameport_device_groups,
796 .drv_groups = gameport_driver_groups,
797 .match = gameport_bus_match,
798 .probe = gameport_driver_probe,
799 .remove = gameport_driver_remove,
800};
801
802static void gameport_set_drv(struct gameport *gameport, struct gameport_driver *drv)
803{
804 mutex_lock(&gameport->drv_mutex);
805 gameport->drv = drv;
806 mutex_unlock(&gameport->drv_mutex);
807}
808
809int gameport_open(struct gameport *gameport, struct gameport_driver *drv, int mode)
810{
811 if (gameport->open) {
812 if (gameport->open(gameport, mode)) {
813 return -1;
814 }
815 } else {
816 if (mode != GAMEPORT_MODE_RAW)
817 return -1;
818 }
819
820 gameport_set_drv(gameport, drv);
821 return 0;
822}
823EXPORT_SYMBOL(gameport_open);
824
825void gameport_close(struct gameport *gameport)
826{
827 del_timer_sync(&gameport->poll_timer);
828 gameport->poll_handler = NULL;
829 gameport->poll_interval = 0;
830 gameport_set_drv(gameport, NULL);
831 if (gameport->close)
832 gameport->close(gameport);
833}
834EXPORT_SYMBOL(gameport_close);
835
836static int __init gameport_init(void)
837{
838 int error;
839
840 error = bus_register(&gameport_bus);
841 if (error) {
842 pr_err("failed to register gameport bus, error: %d\n", error);
843 return error;
844 }
845
846
847 return 0;
848}
849
850static void __exit gameport_exit(void)
851{
852 bus_unregister(&gameport_bus);
853
854 /*
855 * There should not be any outstanding events but work may
856 * still be scheduled so simply cancel it.
857 */
858 cancel_work_sync(&gameport_event_work);
859}
860
861subsys_initcall(gameport_init);
862module_exit(gameport_exit);