summaryrefslogtreecommitdiffstats
path: root/drivers/base/sys.c
blob: fbe72da6c4141e20a1ecda2eb433417acb4bf5cf (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
527
528
529
530
531
532
533
534
535
536
537
538
539
540
541
542
543
544
545
546
547
548
549
550
551
552
553
554
555
556
557
558
559
560
561
562
563
564
565
566
567
568
569
570
571
572
573
574
575
576
577
578
579
580
581
582
583
584
585
586
587
588
589
/*
 * sys.c - pseudo-bus for system 'devices' (cpus, PICs, timers, etc)
 *
 * Copyright (c) 2002-3 Patrick Mochel
 *               2002-3 Open Source Development Lab
 *
 * This file is released under the GPLv2
 *
 * This exports a 'system' bus type.
 * By default, a 'sys' bus gets added to the root of the system. There will
 * always be core system devices. Devices can use sysdev_register() to
 * add themselves as children of the system bus.
 */

#include <linux/sysdev.h>
#include <linux/err.h>
#include <linux/module.h>
#include <linux/kernel.h>
#include <linux/init.h>
#include <linux/string.h>
#include <linux/pm.h>
#include <linux/device.h>
#include <linux/mutex.h>
#include <linux/interrupt.h>

#include "base.h"

#define to_sysdev(k) container_of(k, struct sys_device, kobj)
#define to_sysdev_attr(a) container_of(a, struct sysdev_attribute, attr)


static ssize_t
sysdev_show(struct kobject *kobj, struct attribute *attr, char *buffer)
{
	struct sys_device *sysdev = to_sysdev(kobj);
	struct sysdev_attribute *sysdev_attr = to_sysdev_attr(attr);

	if (sysdev_attr->show)
		return sysdev_attr->show(sysdev, sysdev_attr, buffer);
	return -EIO;
}


static ssize_t
sysdev_store(struct kobject *kobj, struct attribute *attr,
	     const char *buffer, size_t count)
{
	struct sys_device *sysdev = to_sysdev(kobj);
	struct sysdev_attribute *sysdev_attr = to_sysdev_attr(attr);

	if (sysdev_attr->store)
		return sysdev_attr->store(sysdev, sysdev_attr, buffer, count);
	return -EIO;
}

static const struct sysfs_ops sysfs_ops = {
	.show	= sysdev_show,
	.store	= sysdev_store,
};

static struct kobj_type ktype_sysdev = {
	.sysfs_ops	= &sysfs_ops,
};


int sysdev_create_file(struct sys_device *s, struct sysdev_attribute *a)
{
	return sysfs_create_file(&s->kobj, &a->attr);
}


void sysdev_remove_file(struct sys_device *s, struct sysdev_attribute *a)
{
	sysfs_remove_file(&s->kobj, &a->attr);
}

EXPORT_SYMBOL_GPL(sysdev_create_file);
EXPORT_SYMBOL_GPL(sysdev_remove_file);

#define to_sysdev_class(k) container_of(k, struct sysdev_class, kset.kobj)
#define to_sysdev_class_attr(a) container_of(a, \
	struct sysdev_class_attribute, attr)

static ssize_t sysdev_class_show(struct kobject *kobj, struct attribute *attr,
				 char *buffer)
{
	struct sysdev_class *class = to_sysdev_class(kobj);
	struct sysdev_class_attribute *class_attr = to_sysdev_class_attr(attr);

	if (class_attr->show)
		return class_attr->show(class, class_attr, buffer);
	return -EIO;
}

static ssize_t sysdev_class_store(struct kobject *kobj, struct attribute *attr,
				  const char *buffer, size_t count)
{
	struct sysdev_class *class = to_sysdev_class(kobj);
	struct sysdev_class_attribute *class_attr = to_sysdev_class_attr(attr);

	if (class_attr->store)
		return class_attr->store(class, class_attr, buffer, count);
	return -EIO;
}

static const struct sysfs_ops sysfs_class_ops = {
	.show	= sysdev_class_show,
	.store	= sysdev_class_store,
};

static struct kobj_type ktype_sysdev_class = {
	.sysfs_ops	= &sysfs_class_ops,
};

int sysdev_class_create_file(struct sysdev_class *c,
			     struct sysdev_class_attribute *a)
{
	return sysfs_create_file(&c->kset.kobj, &a->attr);
}
EXPORT_SYMBOL_GPL(sysdev_class_create_file);

void sysdev_class_remove_file(struct sysdev_class *c,
			      struct sysdev_class_attribute *a)
{
	sysfs_remove_file(&c->kset.kobj, &a->attr);
}
EXPORT_SYMBOL_GPL(sysdev_class_remove_file);

static struct kset *system_kset;

int sysdev_class_register(struct sysdev_class *cls)
{
	int retval;

	pr_debug("Registering sysdev class '%s'\n", cls->name);

	INIT_LIST_HEAD(&cls->drivers);
	memset(&cls->kset.kobj, 0x00, sizeof(struct kobject));
	cls->kset.kobj.parent = &system_kset->kobj;
	cls->kset.kobj.ktype = &ktype_sysdev_class;
	cls->kset.kobj.kset = system_kset;

	retval = kobject_set_name(&cls->kset.kobj, "%s", cls->name);
	if (retval)
		return retval;

	retval = kset_register(&cls->kset);
	if (!retval && cls->attrs)
		retval = sysfs_create_files(&cls->kset.kobj,
					    (const struct attribute **)cls->attrs);
	return retval;
}

void sysdev_class_unregister(struct sysdev_class *cls)
{
	pr_debug("Unregistering sysdev class '%s'\n",
		 kobject_name(&cls->kset.kobj));
	if (cls->attrs)
		sysfs_remove_files(&cls->kset.kobj,
				   (const struct attribute **)cls->attrs);
	kset_unregister(&cls->kset);
}

EXPORT_SYMBOL_GPL(sysdev_class_register);
EXPORT_SYMBOL_GPL(sysdev_class_unregister);

static DEFINE_MUTEX(sysdev_drivers_lock);

/*
 * @dev != NULL means that we're unwinding because some drv->add()
 * failed for some reason. You need to grab sysdev_drivers_lock before
 * calling this.
 */
static void __sysdev_driver_remove(struct sysdev_class *cls,
				   struct sysdev_driver *drv,
				   struct sys_device *from_dev)
{
	struct sys_device *dev = from_dev;

	list_del_init(&drv->entry);
	if (!cls)
		return;

	if (!drv->remove)
		goto kset_put;

	if (dev)
		list_for_each_entry_continue_reverse(dev, &cls->kset.list,
						     kobj.entry)
			drv->remove(dev);
	else
		list_for_each_entry(dev, &cls->kset.list, kobj.entry)
			drv->remove(dev);

kset_put:
	kset_put(&cls->kset);
}

/**
 *	sysdev_driver_register - Register auxillary driver
 *	@cls:	Device class driver belongs to.
 *	@drv:	Driver.
 *
 *	@drv is inserted into @cls->drivers to be
 *	called on each operation on devices of that class. The refcount
 *	of @cls is incremented.
 */
int sysdev_driver_register(struct sysdev_class *cls, struct sysdev_driver *drv)
{
	struct sys_device *dev = NULL;
	int err = 0;

	if (!cls) {
		WARN(1, KERN_WARNING "sysdev: invalid class passed to %s!\n",
			__func__);
		return -EINVAL;
	}

	/* Check whether this driver has already been added to a class. */
	if (drv->entry.next && !list_empty(&drv->entry))
		WARN(1, KERN_WARNING "sysdev: class %s: driver (%p) has already"
			" been registered to a class, something is wrong, but "
			"will forge on!\n", cls->name, drv);

	mutex_lock(&sysdev_drivers_lock);
	if (cls && kset_get(&cls->kset)) {
		list_add_tail(&drv->entry, &cls->drivers);

		/* If devices of this class already exist, tell the driver */
		if (drv->add) {
			list_for_each_entry(dev, &cls->kset.list, kobj.entry) {
				err = drv->add(dev);
				if (err)
					goto unwind;
			}
		}
	} else {
		err = -EINVAL;
		WARN(1, KERN_ERR "%s: invalid device class\n", __func__);
	}

	goto unlock;

unwind:
	__sysdev_driver_remove(cls, drv, dev);

unlock:
	mutex_unlock(&sysdev_drivers_lock);
	return err;
}

/**
 *	sysdev_driver_unregister - Remove an auxillary driver.
 *	@cls:	Class driver belongs to.
 *	@drv:	Driver.
 */
void sysdev_driver_unregister(struct sysdev_class *cls,
			      struct sysdev_driver *drv)
{
	mutex_lock(&sysdev_drivers_lock);
	__sysdev_driver_remove(cls, drv, NULL);
	mutex_unlock(&sysdev_drivers_lock);
}
EXPORT_SYMBOL_GPL(sysdev_driver_register);
EXPORT_SYMBOL_GPL(sysdev_driver_unregister);

/**
 *	sysdev_register - add a system device to the tree
 *	@sysdev:	device in question
 *
 */
int sysdev_register(struct sys_device *sysdev)
{
	int error;
	struct sysdev_class *cls = sysdev->cls;

	if (!cls)
		return -EINVAL;

	pr_debug("Registering sys device of class '%s'\n",
		 kobject_name(&cls->kset.kobj));

	/* initialize the kobject to 0, in case it had previously been used */
	memset(&sysdev->kobj, 0x00, sizeof(struct kobject));

	/* Make sure the kset is set */
	sysdev->kobj.kset = &cls->kset;

	/* Register the object */
	error = kobject_init_and_add(&sysdev->kobj, &ktype_sysdev, NULL,
				     "%s%d", kobject_name(&cls->kset.kobj),
				     sysdev->id);

	if (!error) {
		struct sysdev_driver *drv;

		pr_debug("Registering sys device '%s'\n",
			 kobject_name(&sysdev->kobj));

		mutex_lock(&sysdev_drivers_lock);
		/* Generic notification is implicit, because it's that
		 * code that should have called us.
		 */

		/* Notify class auxillary drivers */
		list_for_each_entry(drv, &cls->drivers, entry) {
			if (drv->add)
				drv->add(sysdev);
		}
		mutex_unlock(&sysdev_drivers_lock);
		kobject_uevent(&sysdev->kobj, KOBJ_ADD);
	}

	return error;
}

void sysdev_unregister(struct sys_device *sysdev)
{
	struct sysdev_driver *drv;

	mutex_lock(&sysdev_drivers_lock);
	list_for_each_entry(drv, &sysdev->cls->drivers, entry) {
		if (drv->remove)
			drv->remove(sysdev);
	}
	mutex_unlock(&sysdev_drivers_lock);

	kobject_put(&sysdev->kobj);
}


#ifndef CONFIG_ARCH_NO_SYSDEV_OPS
/**
 *	sysdev_shutdown - Shut down all system devices.
 *
 *	Loop over each class of system devices, and the devices in each
 *	of those classes. For each device, we call the shutdown method for
 *	each driver registered for the device - the auxillaries,
 *	and the class driver.
 *
 *	Note: The list is iterated in reverse order, so that we shut down
 *	child devices before we shut down their parents. The list ordering
 *	is guaranteed by virtue of the fact that child devices are registered
 *	after their parents.
 */
void sysdev_shutdown(void)
{
	struct sysdev_class *cls;

	pr_debug("Shutting Down System Devices\n");

	mutex_lock(&sysdev_drivers_lock);
	list_for_each_entry_reverse(cls, &system_kset->list, kset.kobj.entry) {
		struct sys_device *sysdev;

		pr_debug("Shutting down type '%s':\n",
			 kobject_name(&cls->kset.kobj));

		list_for_each_entry(sysdev, &cls->kset.list, kobj.entry) {
			struct sysdev_driver *drv;
			pr_debug(" %s\n", kobject_name(&sysdev->kobj));

			/* Call auxillary drivers first */
			list_for_each_entry(drv, &cls->drivers, entry) {
				if (drv->shutdown)
					drv->shutdown(sysdev);
			}

			/* Now call the generic one */
			if (cls->shutdown)
				cls->shutdown(sysdev);
		}
	}
	mutex_unlock(&sysdev_drivers_lock);
}

static void __sysdev_resume(struct sys_device *dev)
{
	struct sysdev_class *cls = dev->cls;
	struct sysdev_driver *drv;

	/* First, call the class-specific one */
	if (cls->resume)
		cls->resume(dev);
	WARN_ONCE(!irqs_disabled(),
		"Interrupts enabled after %pF\n", cls->resume);

	/* Call auxillary drivers next. */
	list_for_each_entry(drv, &cls->drivers, entry) {
		if (drv->resume)
			drv->resume(dev);
		WARN_ONCE(!irqs_disabled(),
			"Interrupts enabled after %pF\n", drv->resume);
	}
}

/**
 *	sysdev_suspend - Suspend all system devices.
 *	@state:		Power state to enter.
 *
 *	We perform an almost identical operation as sysdev_shutdown()
 *	above, though calling ->suspend() instead. Interrupts are disabled
 *	when this called. Devices are responsible for both saving state and
 *	quiescing or powering down the device.
 *
 *	This is only called by the device PM core, so we let them handle
 *	all synchronization.
 */
int sysdev_suspend(pm_message_t state)
{
	struct sysdev_class *cls;
	struct sys_device *sysdev, *err_dev;
	struct sysdev_driver *drv, *err_drv;
	int ret;

	pr_debug("Checking wake-up interrupts\n");

	/* Return error code if there are any wake-up interrupts pending */
	ret = check_wakeup_irqs();
	if (ret)
		return ret;

	WARN_ONCE(!irqs_disabled(),
		"Interrupts enabled while suspending system devices\n");

	pr_debug("Suspending System Devices\n");

	list_for_each_entry_reverse(cls, &system_kset->list, kset.kobj.entry) {
		pr_debug("Suspending type '%s':\n",
			 kobject_name(&cls->kset.kobj));

		list_for_each_entry(sysdev, &cls->kset.list, kobj.entry) {
			pr_debug(" %s\n", kobject_name(&sysdev->kobj));

			/* Call auxillary drivers first */
			list_for_each_entry(drv, &cls->drivers, entry) {
				if (drv->suspend) {
					ret = drv->suspend(sysdev, state);
					if (ret)
						goto aux_driver;
				}
				WARN_ONCE(!irqs_disabled(),
					"Interrupts enabled after %pF\n",
					drv->suspend);
			}

			/* Now call the generic one */
			if (cls->suspend) {
				ret = cls->suspend(sysdev, state);
				if (ret)
					goto cls_driver;
				WARN_ONCE(!irqs_disabled(),
					"Interrupts enabled after %pF\n",
					cls->suspend);
			}
		}
	}
	return 0;
	/* resume current sysdev */
cls_driver:
	drv = NULL;
	printk(KERN_ERR "Class suspend failed for %s: %d\n",
		kobject_name(&sysdev->kobj), ret);

aux_driver:
	if (drv)
		printk(KERN_ERR "Class driver suspend failed for %s: %d\n",
				kobject_name(&sysdev->kobj), ret);
	list_for_each_entry(err_drv, &cls->drivers, entry) {
		if (err_drv == drv)
			break;
		if (err_drv->resume)
			err_drv->resume(sysdev);
	}

	/* resume other sysdevs in current class */
	list_for_each_entry(err_dev, &cls->kset.list, kobj.entry) {
		if (err_dev == sysdev)
			break;
		pr_debug(" %s\n", kobject_name(&err_dev->kobj));
		__sysdev_resume(err_dev);
	}

	/* resume other classes */
	list_for_each_entry_continue(cls, &system_kset->list, kset.kobj.entry) {
		list_for_each_entry(err_dev, &cls->kset.list, kobj.entry) {
			pr_debug(" %s\n", kobject_name(&err_dev->kobj));
			__sysdev_resume(err_dev);
		}
	}
	return ret;
}
EXPORT_SYMBOL_GPL(sysdev_suspend);

/**
 *	sysdev_resume - Bring system devices back to life.
 *
 *	Similar to sysdev_suspend(), but we iterate the list forwards
 *	to guarantee that parent devices are resumed before their children.
 *
 *	Note: Interrupts are disabled when called.
 */
int sysdev_resume(void)
{
	struct sysdev_class *cls;

	WARN_ONCE(!irqs_disabled(),
		"Interrupts enabled while resuming system devices\n");

	pr_debug("Resuming System Devices\n");

	list_for_each_entry(cls, &system_kset->list, kset.kobj.entry) {
		struct sys_device *sysdev;

		pr_debug("Resuming type '%s':\n",
			 kobject_name(&cls->kset.kobj));

		list_for_each_entry(sysdev, &cls->kset.list, kobj.entry) {
			pr_debug(" %s\n", kobject_name(&sysdev->kobj));

			__sysdev_resume(sysdev);
		}
	}
	return 0;
}
EXPORT_SYMBOL_GPL(sysdev_resume);
#endif /* CONFIG_ARCH_NO_SYSDEV_OPS */

int __init system_bus_init(void)
{
	system_kset = kset_create_and_add("system", NULL, &devices_kset->kobj);
	if (!system_kset)
		return -ENOMEM;
	return 0;
}

EXPORT_SYMBOL_GPL(sysdev_register);
EXPORT_SYMBOL_GPL(sysdev_unregister);

#define to_ext_attr(x) container_of(x, struct sysdev_ext_attribute, attr)

ssize_t sysdev_store_ulong(struct sys_device *sysdev,
			   struct sysdev_attribute *attr,
			   const char *buf, size_t size)
{
	struct sysdev_ext_attribute *ea = to_ext_attr(attr);
	char *end;
	unsigned long new = simple_strtoul(buf, &end, 0);
	if (end == buf)
		return -EINVAL;
	*(unsigned long *)(ea->var) = new;
	/* Always return full write size even if we didn't consume all */
	return size;
}
EXPORT_SYMBOL_GPL(sysdev_store_ulong);

ssize_t sysdev_show_ulong(struct sys_device *sysdev,
			  struct sysdev_attribute *attr,
			  char *buf)
{
	struct sysdev_ext_attribute *ea = to_ext_attr(attr);
	return snprintf(buf, PAGE_SIZE, "%lx\n", *(unsigned long *)(ea->var));
}
EXPORT_SYMBOL_GPL(sysdev_show_ulong);

ssize_t sysdev_store_int(struct sys_device *sysdev,
			   struct sysdev_attribute *attr,
			   const char *buf, size_t size)
{
	struct sysdev_ext_attribute *ea = to_ext_attr(attr);
	char *end;
	long new = simple_strtol(buf, &end, 0);
	if (end == buf || new > INT_MAX || new < INT_MIN)
		return -EINVAL;
	*(int *)(ea->var) = new;
	/* Always return full write size even if we didn't consume all */
	return size;
}
EXPORT_SYMBOL_GPL(sysdev_store_int);

ssize_t sysdev_show_int(struct sys_device *sysdev,
			  struct sysdev_attribute *attr,
			  char *buf)
{
	struct sysdev_ext_attribute *ea = to_ext_attr(attr);
	return snprintf(buf, PAGE_SIZE, "%d\n", *(int *)(ea->var));
}
EXPORT_SYMBOL_GPL(sysdev_show_int);

OpenPOWER on IntegriCloud