summaryrefslogtreecommitdiff
path: root/drivers/s390/cio/ccwgroup.c
blob: 040e643746aa5be7761a003869ef6c8395b124d6 (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
590
591
592
593
594
595
596
597
598
599
600
601
602
603
604
605
606
607
608
609
610
611
612
613
614
615
616
617
618
619
620
621
622
623
624
625
626
627
628
629
630
631
632
633
634
635
636
637
638
639
640
641
642
643
644
645
646
647
648
649
650
/*
 *  bus driver for ccwgroup
 *
 *  Copyright IBM Corp. 2002, 2012
 *
 *  Author(s): Arnd Bergmann (arndb@de.ibm.com)
 *	       Cornelia Huck (cornelia.huck@de.ibm.com)
 */
#include <linux/module.h>
#include <linux/errno.h>
#include <linux/slab.h>
#include <linux/list.h>
#include <linux/device.h>
#include <linux/init.h>
#include <linux/ctype.h>
#include <linux/dcache.h>

#include <asm/cio.h>
#include <asm/ccwdev.h>
#include <asm/ccwgroup.h>

#include "device.h"

#define CCW_BUS_ID_SIZE		10

/* In Linux 2.4, we had a channel device layer called "chandev"
 * that did all sorts of obscure stuff for networking devices.
 * This is another driver that serves as a replacement for just
 * one of its functions, namely the translation of single subchannels
 * to devices that use multiple subchannels.
 */

static struct bus_type ccwgroup_bus_type;

static void __ccwgroup_remove_symlinks(struct ccwgroup_device *gdev)
{
	int i;
	char str[8];

	for (i = 0; i < gdev->count; i++) {
		sprintf(str, "cdev%d", i);
		sysfs_remove_link(&gdev->dev.kobj, str);
		sysfs_remove_link(&gdev->cdev[i]->dev.kobj, "group_device");
	}
}

/*
 * Remove references from ccw devices to ccw group device and from
 * ccw group device to ccw devices.
 */
static void __ccwgroup_remove_cdev_refs(struct ccwgroup_device *gdev)
{
	struct ccw_device *cdev;
	int i;

	for (i = 0; i < gdev->count; i++) {
		cdev = gdev->cdev[i];
		if (!cdev)
			continue;
		spin_lock_irq(cdev->ccwlock);
		dev_set_drvdata(&cdev->dev, NULL);
		spin_unlock_irq(cdev->ccwlock);
		gdev->cdev[i] = NULL;
		put_device(&cdev->dev);
	}
}

/**
 * ccwgroup_set_online() - enable a ccwgroup device
 * @gdev: target ccwgroup device
 *
 * This function attempts to put the ccwgroup device into the online state.
 * Returns:
 *  %0 on success and a negative error value on failure.
 */
int ccwgroup_set_online(struct ccwgroup_device *gdev)
{
	struct ccwgroup_driver *gdrv = to_ccwgroupdrv(gdev->dev.driver);
	int ret = -EINVAL;

	if (atomic_cmpxchg(&gdev->onoff, 0, 1) != 0)
		return -EAGAIN;
	if (gdev->state == CCWGROUP_ONLINE)
		goto out;
	if (gdrv->set_online)
		ret = gdrv->set_online(gdev);
	if (ret)
		goto out;

	gdev->state = CCWGROUP_ONLINE;
out:
	atomic_set(&gdev->onoff, 0);
	return ret;
}
EXPORT_SYMBOL(ccwgroup_set_online);

/**
 * ccwgroup_set_offline() - disable a ccwgroup device
 * @gdev: target ccwgroup device
 *
 * This function attempts to put the ccwgroup device into the offline state.
 * Returns:
 *  %0 on success and a negative error value on failure.
 */
int ccwgroup_set_offline(struct ccwgroup_device *gdev)
{
	struct ccwgroup_driver *gdrv = to_ccwgroupdrv(gdev->dev.driver);
	int ret = -EINVAL;

	if (atomic_cmpxchg(&gdev->onoff, 0, 1) != 0)
		return -EAGAIN;
	if (gdev->state == CCWGROUP_OFFLINE)
		goto out;
	if (gdrv->set_offline)
		ret = gdrv->set_offline(gdev);
	if (ret)
		goto out;

	gdev->state = CCWGROUP_OFFLINE;
out:
	atomic_set(&gdev->onoff, 0);
	return ret;
}
EXPORT_SYMBOL(ccwgroup_set_offline);

static ssize_t ccwgroup_online_store(struct device *dev,
				     struct device_attribute *attr,
				     const char *buf, size_t count)
{
	struct ccwgroup_device *gdev = to_ccwgroupdev(dev);
	unsigned long value;
	int ret;

	device_lock(dev);
	if (!dev->driver) {
		ret = -EINVAL;
		goto out;
	}

	ret = kstrtoul(buf, 0, &value);
	if (ret)
		goto out;

	if (value == 1)
		ret = ccwgroup_set_online(gdev);
	else if (value == 0)
		ret = ccwgroup_set_offline(gdev);
	else
		ret = -EINVAL;
out:
	device_unlock(dev);
	return (ret == 0) ? count : ret;
}

static ssize_t ccwgroup_online_show(struct device *dev,
				    struct device_attribute *attr,
				    char *buf)
{
	struct ccwgroup_device *gdev = to_ccwgroupdev(dev);
	int online;

	online = (gdev->state == CCWGROUP_ONLINE) ? 1 : 0;

	return scnprintf(buf, PAGE_SIZE, "%d\n", online);
}

/*
 * Provide an 'ungroup' attribute so the user can remove group devices no
 * longer needed or accidentially created. Saves memory :)
 */
static void ccwgroup_ungroup(struct ccwgroup_device *gdev)
{
	mutex_lock(&gdev->reg_mutex);
	if (device_is_registered(&gdev->dev)) {
		__ccwgroup_remove_symlinks(gdev);
		device_unregister(&gdev->dev);
		__ccwgroup_remove_cdev_refs(gdev);
	}
	mutex_unlock(&gdev->reg_mutex);
}

static ssize_t ccwgroup_ungroup_store(struct device *dev,
				      struct device_attribute *attr,
				      const char *buf, size_t count)
{
	struct ccwgroup_device *gdev = to_ccwgroupdev(dev);
	int rc;

	/* Prevent concurrent online/offline processing and ungrouping. */
	if (atomic_cmpxchg(&gdev->onoff, 0, 1) != 0)
		return -EAGAIN;
	if (gdev->state != CCWGROUP_OFFLINE) {
		rc = -EINVAL;
		goto out;
	}

	if (device_remove_file_self(dev, attr))
		ccwgroup_ungroup(gdev);
out:
	if (rc) {
		if (rc != -EAGAIN)
			/* Release onoff "lock" when ungrouping failed. */
			atomic_set(&gdev->onoff, 0);
		return rc;
	}
	return count;
}
static DEVICE_ATTR(ungroup, 0200, NULL, ccwgroup_ungroup_store);
static DEVICE_ATTR(online, 0644, ccwgroup_online_show, ccwgroup_online_store);

static struct attribute *ccwgroup_attrs[] = {
	&dev_attr_online.attr,
	&dev_attr_ungroup.attr,
	NULL,
};
static struct attribute_group ccwgroup_attr_group = {
	.attrs = ccwgroup_attrs,
};
static const struct attribute_group *ccwgroup_attr_groups[] = {
	&ccwgroup_attr_group,
	NULL,
};

static void ccwgroup_ungroup_workfn(struct work_struct *work)
{
	struct ccwgroup_device *gdev =
		container_of(work, struct ccwgroup_device, ungroup_work);

	ccwgroup_ungroup(gdev);
	put_device(&gdev->dev);
}

static void ccwgroup_release(struct device *dev)
{
	kfree(to_ccwgroupdev(dev));
}

static int __ccwgroup_create_symlinks(struct ccwgroup_device *gdev)
{
	char str[8];
	int i, rc;

	for (i = 0; i < gdev->count; i++) {
		rc = sysfs_create_link(&gdev->cdev[i]->dev.kobj,
				       &gdev->dev.kobj, "group_device");
		if (rc) {
			for (--i; i >= 0; i--)
				sysfs_remove_link(&gdev->cdev[i]->dev.kobj,
						  "group_device");
			return rc;
		}
	}
	for (i = 0; i < gdev->count; i++) {
		sprintf(str, "cdev%d", i);
		rc = sysfs_create_link(&gdev->dev.kobj,
				       &gdev->cdev[i]->dev.kobj, str);
		if (rc) {
			for (--i; i >= 0; i--) {
				sprintf(str, "cdev%d", i);
				sysfs_remove_link(&gdev->dev.kobj, str);
			}
			for (i = 0; i < gdev->count; i++)
				sysfs_remove_link(&gdev->cdev[i]->dev.kobj,
						  "group_device");
			return rc;
		}
	}
	return 0;
}

static int __get_next_id(const char **buf, struct ccw_dev_id *id)
{
	unsigned int cssid, ssid, devno;
	int ret = 0, len;
	char *start, *end;

	start = (char *)*buf;
	end = strchr(start, ',');
	if (!end) {
		/* Last entry. Strip trailing newline, if applicable. */
		end = strchr(start, '\n');
		if (end)
			*end = '\0';
		len = strlen(start) + 1;
	} else {
		len = end - start + 1;
		end++;
	}
	if (len <= CCW_BUS_ID_SIZE) {
		if (sscanf(start, "%2x.%1x.%04x", &cssid, &ssid, &devno) != 3)
			ret = -EINVAL;
	} else
		ret = -EINVAL;

	if (!ret) {
		id->ssid = ssid;
		id->devno = devno;
	}
	*buf = end;
	return ret;
}

/**
 * ccwgroup_create_dev() - create and register a ccw group device
 * @parent: parent device for the new device
 * @gdrv: driver for the new group device
 * @num_devices: number of slave devices
 * @buf: buffer containing comma separated bus ids of slave devices
 *
 * Create and register a new ccw group device as a child of @parent. Slave
 * devices are obtained from the list of bus ids given in @buf.
 * Returns:
 *  %0 on success and an error code on failure.
 * Context:
 *  non-atomic
 */
int ccwgroup_create_dev(struct device *parent, struct ccwgroup_driver *gdrv,
			int num_devices, const char *buf)
{
	struct ccwgroup_device *gdev;
	struct ccw_dev_id dev_id;
	int rc, i;

	gdev = kzalloc(sizeof(*gdev) + num_devices * sizeof(gdev->cdev[0]),
		       GFP_KERNEL);
	if (!gdev)
		return -ENOMEM;

	atomic_set(&gdev->onoff, 0);
	mutex_init(&gdev->reg_mutex);
	mutex_lock(&gdev->reg_mutex);
	INIT_WORK(&gdev->ungroup_work, ccwgroup_ungroup_workfn);
	gdev->count = num_devices;
	gdev->dev.bus = &ccwgroup_bus_type;
	gdev->dev.parent = parent;
	gdev->dev.release = ccwgroup_release;
	device_initialize(&gdev->dev);

	for (i = 0; i < num_devices && buf; i++) {
		rc = __get_next_id(&buf, &dev_id);
		if (rc != 0)
			goto error;
		gdev->cdev[i] = get_ccwdev_by_dev_id(&dev_id);
		/*
		 * All devices have to be of the same type in
		 * order to be grouped.
		 */
		if (!gdev->cdev[i] || !gdev->cdev[i]->drv ||
		    gdev->cdev[i]->drv != gdev->cdev[0]->drv ||
		    gdev->cdev[i]->id.driver_info !=
		    gdev->cdev[0]->id.driver_info) {
			rc = -EINVAL;
			goto error;
		}
		/* Don't allow a device to belong to more than one group. */
		spin_lock_irq(gdev->cdev[i]->ccwlock);
		if (dev_get_drvdata(&gdev->cdev[i]->dev)) {
			spin_unlock_irq(gdev->cdev[i]->ccwlock);
			rc = -EINVAL;
			goto error;
		}
		dev_set_drvdata(&gdev->cdev[i]->dev, gdev);
		spin_unlock_irq(gdev->cdev[i]->ccwlock);
	}
	/* Check for sufficient number of bus ids. */
	if (i < num_devices) {
		rc = -EINVAL;
		goto error;
	}
	/* Check for trailing stuff. */
	if (i == num_devices && strlen(buf) > 0) {
		rc = -EINVAL;
		goto error;
	}

	dev_set_name(&gdev->dev, "%s", dev_name(&gdev->cdev[0]->dev));
	gdev->dev.groups = ccwgroup_attr_groups;

	if (gdrv) {
		gdev->dev.driver = &gdrv->driver;
		rc = gdrv->setup ? gdrv->setup(gdev) : 0;
		if (rc)
			goto error;
	}
	rc = device_add(&gdev->dev);
	if (rc)
		goto error;
	rc = __ccwgroup_create_symlinks(gdev);
	if (rc) {
		device_del(&gdev->dev);
		goto error;
	}
	mutex_unlock(&gdev->reg_mutex);
	return 0;
error:
	for (i = 0; i < num_devices; i++)
		if (gdev->cdev[i]) {
			spin_lock_irq(gdev->cdev[i]->ccwlock);
			if (dev_get_drvdata(&gdev->cdev[i]->dev) == gdev)
				dev_set_drvdata(&gdev->cdev[i]->dev, NULL);
			spin_unlock_irq(gdev->cdev[i]->ccwlock);
			put_device(&gdev->cdev[i]->dev);
			gdev->cdev[i] = NULL;
		}
	mutex_unlock(&gdev->reg_mutex);
	put_device(&gdev->dev);
	return rc;
}
EXPORT_SYMBOL(ccwgroup_create_dev);

static int ccwgroup_notifier(struct notifier_block *nb, unsigned long action,
			     void *data)
{
	struct ccwgroup_device *gdev = to_ccwgroupdev(data);

	if (action == BUS_NOTIFY_UNBIND_DRIVER) {
		get_device(&gdev->dev);
		schedule_work(&gdev->ungroup_work);
	}

	return NOTIFY_OK;
}

static struct notifier_block ccwgroup_nb = {
	.notifier_call = ccwgroup_notifier
};

static int __init init_ccwgroup(void)
{
	int ret;

	ret = bus_register(&ccwgroup_bus_type);
	if (ret)
		return ret;

	ret = bus_register_notifier(&ccwgroup_bus_type, &ccwgroup_nb);
	if (ret)
		bus_unregister(&ccwgroup_bus_type);

	return ret;
}

static void __exit cleanup_ccwgroup(void)
{
	bus_unregister_notifier(&ccwgroup_bus_type, &ccwgroup_nb);
	bus_unregister(&ccwgroup_bus_type);
}

module_init(init_ccwgroup);
module_exit(cleanup_ccwgroup);

/************************** driver stuff ******************************/

static int ccwgroup_remove(struct device *dev)
{
	struct ccwgroup_device *gdev = to_ccwgroupdev(dev);
	struct ccwgroup_driver *gdrv = to_ccwgroupdrv(dev->driver);

	if (!dev->driver)
		return 0;
	if (gdrv->remove)
		gdrv->remove(gdev);

	return 0;
}

static void ccwgroup_shutdown(struct device *dev)
{
	struct ccwgroup_device *gdev = to_ccwgroupdev(dev);
	struct ccwgroup_driver *gdrv = to_ccwgroupdrv(dev->driver);

	if (!dev->driver)
		return;
	if (gdrv->shutdown)
		gdrv->shutdown(gdev);
}

static int ccwgroup_pm_prepare(struct device *dev)
{
	struct ccwgroup_device *gdev = to_ccwgroupdev(dev);
	struct ccwgroup_driver *gdrv = to_ccwgroupdrv(gdev->dev.driver);

	/* Fail while device is being set online/offline. */
	if (atomic_read(&gdev->onoff))
		return -EAGAIN;

	if (!gdev->dev.driver || gdev->state != CCWGROUP_ONLINE)
		return 0;

	return gdrv->prepare ? gdrv->prepare(gdev) : 0;
}

static void ccwgroup_pm_complete(struct device *dev)
{
	struct ccwgroup_device *gdev = to_ccwgroupdev(dev);
	struct ccwgroup_driver *gdrv = to_ccwgroupdrv(dev->driver);

	if (!gdev->dev.driver || gdev->state != CCWGROUP_ONLINE)
		return;

	if (gdrv->complete)
		gdrv->complete(gdev);
}

static int ccwgroup_pm_freeze(struct device *dev)
{
	struct ccwgroup_device *gdev = to_ccwgroupdev(dev);
	struct ccwgroup_driver *gdrv = to_ccwgroupdrv(gdev->dev.driver);

	if (!gdev->dev.driver || gdev->state != CCWGROUP_ONLINE)
		return 0;

	return gdrv->freeze ? gdrv->freeze(gdev) : 0;
}

static int ccwgroup_pm_thaw(struct device *dev)
{
	struct ccwgroup_device *gdev = to_ccwgroupdev(dev);
	struct ccwgroup_driver *gdrv = to_ccwgroupdrv(gdev->dev.driver);

	if (!gdev->dev.driver || gdev->state != CCWGROUP_ONLINE)
		return 0;

	return gdrv->thaw ? gdrv->thaw(gdev) : 0;
}

static int ccwgroup_pm_restore(struct device *dev)
{
	struct ccwgroup_device *gdev = to_ccwgroupdev(dev);
	struct ccwgroup_driver *gdrv = to_ccwgroupdrv(gdev->dev.driver);

	if (!gdev->dev.driver || gdev->state != CCWGROUP_ONLINE)
		return 0;

	return gdrv->restore ? gdrv->restore(gdev) : 0;
}

static const struct dev_pm_ops ccwgroup_pm_ops = {
	.prepare = ccwgroup_pm_prepare,
	.complete = ccwgroup_pm_complete,
	.freeze = ccwgroup_pm_freeze,
	.thaw = ccwgroup_pm_thaw,
	.restore = ccwgroup_pm_restore,
};

static struct bus_type ccwgroup_bus_type = {
	.name   = "ccwgroup",
	.remove = ccwgroup_remove,
	.shutdown = ccwgroup_shutdown,
	.pm = &ccwgroup_pm_ops,
};

/**
 * ccwgroup_driver_register() - register a ccw group driver
 * @cdriver: driver to be registered
 *
 * This function is mainly a wrapper around driver_register().
 */
int ccwgroup_driver_register(struct ccwgroup_driver *cdriver)
{
	/* register our new driver with the core */
	cdriver->driver.bus = &ccwgroup_bus_type;

	return driver_register(&cdriver->driver);
}
EXPORT_SYMBOL(ccwgroup_driver_register);

static int __ccwgroup_match_all(struct device *dev, void *data)
{
	return 1;
}

/**
 * ccwgroup_driver_unregister() - deregister a ccw group driver
 * @cdriver: driver to be deregistered
 *
 * This function is mainly a wrapper around driver_unregister().
 */
void ccwgroup_driver_unregister(struct ccwgroup_driver *cdriver)
{
	struct device *dev;

	/* We don't want ccwgroup devices to live longer than their driver. */
	while ((dev = driver_find_device(&cdriver->driver, NULL, NULL,
					 __ccwgroup_match_all))) {
		struct ccwgroup_device *gdev = to_ccwgroupdev(dev);

		mutex_lock(&gdev->reg_mutex);
		__ccwgroup_remove_symlinks(gdev);
		device_unregister(dev);
		__ccwgroup_remove_cdev_refs(gdev);
		mutex_unlock(&gdev->reg_mutex);
		put_device(dev);
	}
	driver_unregister(&cdriver->driver);
}
EXPORT_SYMBOL(ccwgroup_driver_unregister);

/**
 * ccwgroup_probe_ccwdev() - probe function for slave devices
 * @cdev: ccw device to be probed
 *
 * This is a dummy probe function for ccw devices that are slave devices in
 * a ccw group device.
 * Returns:
 *  always %0
 */
int ccwgroup_probe_ccwdev(struct ccw_device *cdev)
{
	return 0;
}
EXPORT_SYMBOL(ccwgroup_probe_ccwdev);

/**
 * ccwgroup_remove_ccwdev() - remove function for slave devices
 * @cdev: ccw device to be removed
 *
 * This is a remove function for ccw devices that are slave devices in a ccw
 * group device. It sets the ccw device offline and also deregisters the
 * embedding ccw group device.
 */
void ccwgroup_remove_ccwdev(struct ccw_device *cdev)
{
	struct ccwgroup_device *gdev;

	/* Ignore offlining errors, device is gone anyway. */
	ccw_device_set_offline(cdev);
	/* If one of its devices is gone, the whole group is done for. */
	spin_lock_irq(cdev->ccwlock);
	gdev = dev_get_drvdata(&cdev->dev);
	if (!gdev) {
		spin_unlock_irq(cdev->ccwlock);
		return;
	}
	/* Get ccwgroup device reference for local processing. */
	get_device(&gdev->dev);
	spin_unlock_irq(cdev->ccwlock);
	/* Unregister group device. */
	mutex_lock(&gdev->reg_mutex);
	if (device_is_registered(&gdev->dev)) {
		__ccwgroup_remove_symlinks(gdev);
		device_unregister(&gdev->dev);
		__ccwgroup_remove_cdev_refs(gdev);
	}
	mutex_unlock(&gdev->reg_mutex);
	/* Release ccwgroup device reference for local processing. */
	put_device(&gdev->dev);
}
EXPORT_SYMBOL(ccwgroup_remove_ccwdev);
MODULE_LICENSE("GPL");