aboutsummaryrefslogtreecommitdiff
path: root/drivers/s390/cio/ccwgroup.c
blob: fe1ad1722158818f9ba594a455bb7f3b542e7fbe (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
/*
 *  drivers/s390/cio/ccwgroup.c
 *  bus driver for ccwgroup
 *
 *    Copyright (C) 2002 IBM Deutschland Entwicklung GmbH,
 *                       IBM Corporation
 *    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/ccwdev.h>
#include <asm/ccwgroup.h>

/* 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.
 */

/* a device matches a driver if all its slave devices match the same
 * entry of the driver */
static int
ccwgroup_bus_match (struct device * dev, struct device_driver * drv)
{
	struct ccwgroup_device *gdev;
	struct ccwgroup_driver *gdrv;

	gdev = to_ccwgroupdev(dev);
	gdrv = to_ccwgroupdrv(drv);

	if (gdev->creator_id == gdrv->driver_id)
		return 1;

	return 0;
}
static int
ccwgroup_uevent (struct device *dev, struct kobj_uevent_env *env)
{
	/* TODO */
	return 0;
}

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");
	}
	
}

/*
 * Provide an 'ungroup' attribute so the user can remove group devices no
 * longer needed or accidentially created. Saves memory :)
 */
static void ccwgroup_ungroup_callback(struct device *dev)
{
	struct ccwgroup_device *gdev = to_ccwgroupdev(dev);

	mutex_lock(&gdev->reg_mutex);
	if (device_is_registered(&gdev->dev)) {
		__ccwgroup_remove_symlinks(gdev);
		device_unregister(dev);
	}
	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;
	int rc;

	gdev = to_ccwgroupdev(dev);

	if (gdev->state != CCWGROUP_OFFLINE)
		return -EINVAL;

	/* Note that we cannot unregister the device from one of its
	 * attribute methods, so we have to use this roundabout approach.
	 */
	rc = device_schedule_callback(dev, ccwgroup_ungroup_callback);
	if (rc)
		count = rc;
	return count;
}

static DEVICE_ATTR(ungroup, 0200, NULL, ccwgroup_ungroup_store);

static void
ccwgroup_release (struct device *dev)
{
	struct ccwgroup_device *gdev;
	int i;

	gdev = to_ccwgroupdev(dev);

	for (i = 0; i < gdev->count; i++) {
		dev_set_drvdata(&gdev->cdev[i]->dev, NULL);
		put_device(&gdev->cdev[i]->dev);
	}
	kfree(gdev);
}

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;
}

/**
 * ccwgroup_create() - create and register a ccw group device
 * @root: parent device for the new device
 * @creator_id: identifier of creating driver
 * @cdrv: ccw driver of slave devices
 * @argc: number of slave devices
 * @argv: bus ids of slave devices
 *
 * Create and register a new ccw group device as a child of @root. Slave
 * devices are obtained from the list of bus ids given in @argv[] and must all
 * belong to @cdrv.
 * Returns:
 *  %0 on success and an error code on failure.
 * Context:
 *  non-atomic
 */
int ccwgroup_create(struct device *root, unsigned int creator_id,
		    struct ccw_driver *cdrv, int argc, char *argv[])
{
	struct ccwgroup_device *gdev;
	int i;
	int rc;

	if (argc > 256) /* disallow dumb users */
		return -EINVAL;

	gdev = kzalloc(sizeof(*gdev) + argc*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);
	for (i = 0; i < argc; i++) {
		gdev->cdev[i] = get_ccwdev_by_busid(cdrv, argv[i]);

		/* all devices have to be of the same type in
		 * order to be grouped */
		if (!gdev->cdev[i]
		    || 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. */
		if (dev_get_drvdata(&gdev->cdev[i]->dev)) {
			rc = -EINVAL;
			goto error;
		}
		dev_set_drvdata(&gdev->cdev[i]->dev, gdev);
	}

	gdev->creator_id = creator_id;
	gdev->count = argc;
	gdev->dev.bus = &ccwgroup_bus_type;
	gdev->dev.parent = root;
	gdev->dev.release = ccwgroup_release;

	snprintf (gdev->dev.bus_id, BUS_ID_SIZE, "%s",
			gdev->cdev[0]->dev.bus_id);

	rc = device_register(&gdev->dev);
	if (rc)
		goto error;
	get_device(&gdev->dev);
	rc = device_create_file(&gdev->dev, &dev_attr_ungroup);

	if (rc) {
		device_unregister(&gdev->dev);
		goto error;
	}

	rc = __ccwgroup_create_symlinks(gdev);
	if (!rc) {
		mutex_unlock(&gdev->reg_mutex);
		put_device(&gdev->dev);
		return 0;
	}
	device_remove_file(&gdev->dev, &dev_attr_ungroup);
	device_unregister(&gdev->dev);
error:
	for (i = 0; i < argc; i++)
		if (gdev->cdev[i]) {
			if (dev_get_drvdata(&gdev->cdev[i]->dev) == gdev)
				dev_set_drvdata(&gdev->cdev[i]->dev, NULL);
			put_device(&gdev->cdev[i]->dev);
		}
	mutex_unlock(&gdev->reg_mutex);
	put_device(&gdev->dev);
	return rc;
}

static int __init
init_ccwgroup (void)
{
	return bus_register (&ccwgroup_bus_type);
}

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

module_init(init_ccwgroup);
module_exit(cleanup_ccwgroup);

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

static int
ccwgroup_set_online(struct ccwgroup_device *gdev)
{
	struct ccwgroup_driver *gdrv;
	int ret;

	if (atomic_cmpxchg(&gdev->onoff, 0, 1) != 0)
		return -EAGAIN;
	if (gdev->state == CCWGROUP_ONLINE) {
		ret = 0;
		goto out;
	}
	if (!gdev->dev.driver) {
		ret = -EINVAL;
		goto out;
	}
	gdrv = to_ccwgroupdrv (gdev->dev.driver);
	if ((ret = gdrv->set_online ? gdrv->set_online(gdev) : 0))
		goto out;

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

static int
ccwgroup_set_offline(struct ccwgroup_device *gdev)
{
	struct ccwgroup_driver *gdrv;
	int ret;

	if (atomic_cmpxchg(&gdev->onoff, 0, 1) != 0)
		return -EAGAIN;
	if (gdev->state == CCWGROUP_OFFLINE) {
		ret = 0;
		goto out;
	}
	if (!gdev->dev.driver) {
		ret = -EINVAL;
		goto out;
	}
	gdrv = to_ccwgroupdrv (gdev->dev.driver);
	if ((ret = gdrv->set_offline ? gdrv->set_offline(gdev) : 0))
		goto out;

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

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

	gdev = to_ccwgroupdev(dev);
	if (!dev->driver)
		return count;

	gdrv = to_ccwgroupdrv (gdev->dev.driver);
	if (!try_module_get(gdrv->owner))
		return -EINVAL;

	value = simple_strtoul(buf, NULL, 0);
	ret = count;
	if (value == 1)
		ccwgroup_set_online(gdev);
	else if (value == 0)
		ccwgroup_set_offline(gdev);
	else
		ret = -EINVAL;
	module_put(gdrv->owner);
	return ret;
}

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

	online = (to_ccwgroupdev(dev)->state == CCWGROUP_ONLINE);

	return sprintf(buf, online ? "1\n" : "0\n");
}

static DEVICE_ATTR(online, 0644, ccwgroup_online_show, ccwgroup_online_store);

static int
ccwgroup_probe (struct device *dev)
{
	struct ccwgroup_device *gdev;
	struct ccwgroup_driver *gdrv;

	int ret;

	gdev = to_ccwgroupdev(dev);
	gdrv = to_ccwgroupdrv(dev->driver);

	if ((ret = device_create_file(dev, &dev_attr_online)))
		return ret;

	ret = gdrv->probe ? gdrv->probe(gdev) : -ENODEV;
	if (ret)
		device_remove_file(dev, &dev_attr_online);

	return ret;
}

static int
ccwgroup_remove (struct device *dev)
{
	struct ccwgroup_device *gdev;
	struct ccwgroup_driver *gdrv;

	gdev = to_ccwgroupdev(dev);
	gdrv = to_ccwgroupdrv(dev->driver);

	device_remove_file(dev, &dev_attr_online);

	if (gdrv && gdrv->remove)
		gdrv->remove(gdev);
	return 0;
}

static void ccwgroup_shutdown(struct device *dev)
{
	struct ccwgroup_device *gdev;
	struct ccwgroup_driver *gdrv;

	gdev = to_ccwgroupdev(dev);
	gdrv = to_ccwgroupdrv(dev->driver);
	if (gdrv && gdrv->shutdown)
		gdrv->shutdown(gdev);
}

static struct bus_type ccwgroup_bus_type = {
	.name   = "ccwgroup",
	.match  = ccwgroup_bus_match,
	.uevent = ccwgroup_uevent,
	.probe  = ccwgroup_probe,
	.remove = ccwgroup_remove,
	.shutdown = ccwgroup_shutdown,
};

/**
 * 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;
	cdriver->driver.name = cdriver->name;
	cdriver->driver.owner = cdriver->owner;

	return driver_register(&cdriver->driver);
}

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. */
	get_driver(&cdriver->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);
		mutex_unlock(&gdev->reg_mutex);
		put_device(dev);
	}
	put_driver(&cdriver->driver);
	driver_unregister(&cdriver->driver);
}

/**
 * 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;
}

static struct ccwgroup_device *
__ccwgroup_get_gdev_by_cdev(struct ccw_device *cdev)
{
	struct ccwgroup_device *gdev;

	gdev = dev_get_drvdata(&cdev->dev);
	if (gdev) {
		if (get_device(&gdev->dev)) {
			mutex_lock(&gdev->reg_mutex);
			if (device_is_registered(&gdev->dev))
				return gdev;
			mutex_unlock(&gdev->reg_mutex);
			put_device(&gdev->dev);
		}
		return NULL;
	}
	return NULL;
}

/**
 * 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. */
	gdev = __ccwgroup_get_gdev_by_cdev(cdev);
	if (gdev) {
		__ccwgroup_remove_symlinks(gdev);
		device_unregister(&gdev->dev);
		mutex_unlock(&gdev->reg_mutex);
		put_device(&gdev->dev);
	}
}

MODULE_LICENSE("GPL");
EXPORT_SYMBOL(ccwgroup_driver_register);
EXPORT_SYMBOL(ccwgroup_driver_unregister);
EXPORT_SYMBOL(ccwgroup_create);
EXPORT_SYMBOL(ccwgroup_probe_ccwdev);
EXPORT_SYMBOL(ccwgroup_remove_ccwdev);