1 /*
2 * drivers/s390/cio/ccwgroup.c
3 * bus driver for ccwgroup
4 *
5 * Copyright (C) 2002 IBM Deutschland Entwicklung GmbH,
6 * IBM Corporation
7 * Author(s): Arnd Bergmann (arndb@de.ibm.com)
8 * Cornelia Huck (cornelia.huck@de.ibm.com)
9 */
10 #include <linux/module.h>
11 #include <linux/errno.h>
12 #include <linux/slab.h>
13 #include <linux/list.h>
14 #include <linux/device.h>
15 #include <linux/init.h>
16 #include <linux/ctype.h>
17 #include <linux/dcache.h>
18
19 #include <asm/semaphore.h>
20 #include <asm/ccwdev.h>
21 #include <asm/ccwgroup.h>
22
23 /* In Linux 2.4, we had a channel device layer called "chandev"
24 * that did all sorts of obscure stuff for networking devices.
25 * This is another driver that serves as a replacement for just
26 * one of its functions, namely the translation of single subchannels
27 * to devices that use multiple subchannels.
28 */
29
30 /* a device matches a driver if all its slave devices match the same
31 * entry of the driver */
32 static int
33 ccwgroup_bus_match (struct device * dev, struct device_driver * drv)
34 {
35 struct ccwgroup_device *gdev;
36 struct ccwgroup_driver *gdrv;
37
38 gdev = to_ccwgroupdev(dev);
39 gdrv = to_ccwgroupdrv(drv);
40
41 if (gdev->creator_id == gdrv->driver_id)
42 return 1;
43
44 return 0;
45 }
46 static int
47 ccwgroup_uevent (struct device *dev, struct kobj_uevent_env *env)
48 {
49 /* TODO */
50 return 0;
51 }
52
53 static struct bus_type ccwgroup_bus_type;
54
55 static void
56 __ccwgroup_remove_symlinks(struct ccwgroup_device *gdev)
57 {
58 int i;
59 char str[8];
60
61 for (i = 0; i < gdev->count; i++) {
62 sprintf(str, "cdev%d", i);
63 sysfs_remove_link(&gdev->dev.kobj, str);
64 sysfs_remove_link(&gdev->cdev[i]->dev.kobj, "group_device");
65 }
66
67 }
68
69 /*
70 * Provide an 'ungroup' attribute so the user can remove group devices no
71 * longer needed or accidentially created. Saves memory :)
72 */
73 static void ccwgroup_ungroup_callback(struct device *dev)
74 {
75 struct ccwgroup_device *gdev = to_ccwgroupdev(dev);
76
77 mutex_lock(&gdev->reg_mutex);
78 if (device_is_registered(&gdev->dev)) {
79 __ccwgroup_remove_symlinks(gdev);
80 device_unregister(dev);
81 }
82 mutex_unlock(&gdev->reg_mutex);
83 }
84
85 static ssize_t
86 ccwgroup_ungroup_store(struct device *dev, struct device_attribute *attr, const char *buf, size_t count)
87 {
88 struct ccwgroup_device *gdev;
89 int rc;
90
91 gdev = to_ccwgroupdev(dev);
92
93 if (gdev->state != CCWGROUP_OFFLINE)
94 return -EINVAL;
95
96 /* Note that we cannot unregister the device from one of its
97 * attribute methods, so we have to use this roundabout approach.
98 */
99 rc = device_schedule_callback(dev, ccwgroup_ungroup_callback);
100 if (rc)
101 count = rc;
102 return count;
103 }
104
105 static DEVICE_ATTR(ungroup, 0200, NULL, ccwgroup_ungroup_store);
106
107 static void
108 ccwgroup_release (struct device *dev)
109 {
110 struct ccwgroup_device *gdev;
111 int i;
112
113 gdev = to_ccwgroupdev(dev);
114
115 for (i = 0; i < gdev->count; i++) {
116 dev_set_drvdata(&gdev->cdev[i]->dev, NULL);
117 put_device(&gdev->cdev[i]->dev);
118 }
119 kfree(gdev);
120 }
121
122 static int
123 __ccwgroup_create_symlinks(struct ccwgroup_device *gdev)
124 {
125 char str[8];
126 int i, rc;
127
128 for (i = 0; i < gdev->count; i++) {
129 rc = sysfs_create_link(&gdev->cdev[i]->dev.kobj, &gdev->dev.kobj,
130 "group_device");
131 if (rc) {
132 for (--i; i >= 0; i--)
133 sysfs_remove_link(&gdev->cdev[i]->dev.kobj,
134 "group_device");
135 return rc;
136 }
137 }
138 for (i = 0; i < gdev->count; i++) {
139 sprintf(str, "cdev%d", i);
140 rc = sysfs_create_link(&gdev->dev.kobj, &gdev->cdev[i]->dev.kobj,
141 str);
142 if (rc) {
143 for (--i; i >= 0; i--) {
144 sprintf(str, "cdev%d", i);
145 sysfs_remove_link(&gdev->dev.kobj, str);
146 }
147 for (i = 0; i < gdev->count; i++)
148 sysfs_remove_link(&gdev->cdev[i]->dev.kobj,
149 "group_device");
150 return rc;
151 }
152 }
153 return 0;
154 }
155
156 /**
157 * ccwgroup_create() - create and register a ccw group device
158 * @root: parent device for the new device
159 * @creator_id: identifier of creating driver
160 * @cdrv: ccw driver of slave devices
161 * @argc: number of slave devices
162 * @argv: bus ids of slave devices
163 *
164 * Create and register a new ccw group device as a child of @root. Slave
165 * devices are obtained from the list of bus ids given in @argv[] and must all
166 * belong to @cdrv.
167 * Returns:
168 * %0 on success and an error code on failure.
169 * Context:
170 * non-atomic
171 */
172 int ccwgroup_create(struct device *root, unsigned int creator_id,
173 struct ccw_driver *cdrv, int argc, char *argv[])
174 {
175 struct ccwgroup_device *gdev;
176 int i;
177 int rc;
178
179 if (argc > 256) /* disallow dumb users */
180 return -EINVAL;
181
182 gdev = kzalloc(sizeof(*gdev) + argc*sizeof(gdev->cdev[0]), GFP_KERNEL);
183 if (!gdev)
184 return -ENOMEM;
185
186 atomic_set(&gdev->onoff, 0);
187 mutex_init(&gdev->reg_mutex);
188 mutex_lock(&gdev->reg_mutex);
189 for (i = 0; i < argc; i++) {
190 gdev->cdev[i] = get_ccwdev_by_busid(cdrv, argv[i]);
191
192 /* all devices have to be of the same type in
193 * order to be grouped */
194 if (!gdev->cdev[i]
195 || gdev->cdev[i]->id.driver_info !=
196 gdev->cdev[0]->id.driver_info) {
197 rc = -EINVAL;
198 goto error;
199 }
200 /* Don't allow a device to belong to more than one group. */
201 if (dev_get_drvdata(&gdev->cdev[i]->dev)) {
202 rc = -EINVAL;
203 goto error;
204 }
205 dev_set_drvdata(&gdev->cdev[i]->dev, gdev);
206 }
207
208 gdev->creator_id = creator_id;
209 gdev->count = argc;
210 gdev->dev.bus = &ccwgroup_bus_type;
211 gdev->dev.parent = root;
212 gdev->dev.release = ccwgroup_release;
213
214 snprintf (gdev->dev.bus_id, BUS_ID_SIZE, "%s",
215 gdev->cdev[0]->dev.bus_id);
216
217 rc = device_register(&gdev->dev);
218 if (rc)
219 goto error;
220 get_device(&gdev->dev);
221 rc = device_create_file(&gdev->dev, &dev_attr_ungroup);
222
223 if (rc) {
224 device_unregister(&gdev->dev);
225 goto error;
226 }
227
228 rc = __ccwgroup_create_symlinks(gdev);
229 if (!rc) {
230 mutex_unlock(&gdev->reg_mutex);
231 put_device(&gdev->dev);
232 return 0;
233 }
234 device_remove_file(&gdev->dev, &dev_attr_ungroup);
235 device_unregister(&gdev->dev);
236 error:
237 for (i = 0; i < argc; i++)
238 if (gdev->cdev[i]) {
239 if (dev_get_drvdata(&gdev->cdev[i]->dev) == gdev)
240 dev_set_drvdata(&gdev->cdev[i]->dev, NULL);
241 put_device(&gdev->cdev[i]->dev);
242 }
243 mutex_unlock(&gdev->reg_mutex);
244 put_device(&gdev->dev);
245 return rc;
246 }
247
248 static int __init
249 init_ccwgroup (void)
250 {
251 return bus_register (&ccwgroup_bus_type);
252 }
253
254 static void __exit
255 cleanup_ccwgroup (void)
256 {
257 bus_unregister (&ccwgroup_bus_type);
258 }
259
260 module_init(init_ccwgroup);
261 module_exit(cleanup_ccwgroup);
262
263 /************************** driver stuff ******************************/
264
265 static int
266 ccwgroup_set_online(struct ccwgroup_device *gdev)
267 {
268 struct ccwgroup_driver *gdrv;
269 int ret;
270
271 if (atomic_cmpxchg(&gdev->onoff, 0, 1) != 0)
272 return -EAGAIN;
273 if (gdev->state == CCWGROUP_ONLINE) {
274 ret = 0;
275 goto out;
276 }
277 if (!gdev->dev.driver) {
278 ret = -EINVAL;
279 goto out;
280 }
281 gdrv = to_ccwgroupdrv (gdev->dev.driver);
282 if ((ret = gdrv->set_online ? gdrv->set_online(gdev) : 0))
283 goto out;
284
285 gdev->state = CCWGROUP_ONLINE;
286 out:
287 atomic_set(&gdev->onoff, 0);
288 return ret;
289 }
290
291 static int
292 ccwgroup_set_offline(struct ccwgroup_device *gdev)
293 {
294 struct ccwgroup_driver *gdrv;
295 int ret;
296
297 if (atomic_cmpxchg(&gdev->onoff, 0, 1) != 0)
298 return -EAGAIN;
299 if (gdev->state == CCWGROUP_OFFLINE) {
300 ret = 0;
301 goto out;
302 }
303 if (!gdev->dev.driver) {
304 ret = -EINVAL;
305 goto out;
306 }
307 gdrv = to_ccwgroupdrv (gdev->dev.driver);
308 if ((ret = gdrv->set_offline ? gdrv->set_offline(gdev) : 0))
309 goto out;
310
311 gdev->state = CCWGROUP_OFFLINE;
312 out:
313 atomic_set(&gdev->onoff, 0);
314 return ret;
315 }
316
317 static ssize_t
318 ccwgroup_online_store (struct device *dev, struct device_attribute *attr, const char *buf, size_t count)
319 {
320 struct ccwgroup_device *gdev;
321 struct ccwgroup_driver *gdrv;
322 unsigned int value;
323 int ret;
324
325 gdev = to_ccwgroupdev(dev);
326 if (!dev->driver)
327 return count;
328
329 gdrv = to_ccwgroupdrv (gdev->dev.driver);
330 if (!try_module_get(gdrv->owner))
331 return -EINVAL;
332
333 value = simple_strtoul(buf, NULL, 0);
334 ret = count;
335 if (value == 1)
336 ccwgroup_set_online(gdev);
337 else if (value == 0)
338 ccwgroup_set_offline(gdev);
339 else
340 ret = -EINVAL;
341 module_put(gdrv->owner);
342 return ret;
343 }
344
345 static ssize_t
346 ccwgroup_online_show (struct device *dev, struct device_attribute *attr, char *buf)
347 {
348 int online;
349
350 online = (to_ccwgroupdev(dev)->state == CCWGROUP_ONLINE);
351
352 return sprintf(buf, online ? "1\n" : "\n");
353 }
354
355 static DEVICE_ATTR(online, 0644, ccwgroup_online_show, ccwgroup_online_store);
356
357 static int
358 ccwgroup_probe (struct device *dev)
359 {
360 struct ccwgroup_device *gdev;
361 struct ccwgroup_driver *gdrv;
362
363 int ret;
364
365 gdev = to_ccwgroupdev(dev);
366 gdrv = to_ccwgroupdrv(dev->driver);
367
368 if ((ret = device_create_file(dev, &dev_attr_online)))
369 return ret;
370
371 ret = gdrv->probe ? gdrv->probe(gdev) : -ENODEV;
372 if (ret)
373 device_remove_file(dev, &dev_attr_online);
374
375 return ret;
376 }
377
378 static int
379 ccwgroup_remove (struct device *dev)
380 {
381 struct ccwgroup_device *gdev;
382 struct ccwgroup_driver *gdrv;
383
384 gdev = to_ccwgroupdev(dev);
385 gdrv = to_ccwgroupdrv(dev->driver);
386
387 device_remove_file(dev, &dev_attr_online);
388
389 if (gdrv && gdrv->remove)
390 gdrv->remove(gdev);
391 return 0;
392 }
393
394 static void ccwgroup_shutdown(struct device *dev)
395 {
396 struct ccwgroup_device *gdev;
397 struct ccwgroup_driver *gdrv;
398
399 gdev = to_ccwgroupdev(dev);
400 gdrv = to_ccwgroupdrv(dev->driver);
401 if (gdrv && gdrv->shutdown)
402 gdrv->shutdown(gdev);
403 }
404
405 static struct bus_type ccwgroup_bus_type = {
406 .name = "ccwgroup",
407 .match = ccwgroup_bus_match,
408 .uevent = ccwgroup_uevent,
409 .probe = ccwgroup_probe,
410 .remove = ccwgroup_remove,
411 .shutdown = ccwgroup_shutdown,
412 };
413
414 /**
415 * ccwgroup_driver_register() - register a ccw group driver
416 * @cdriver: driver to be registered
417 *
418 * This function is mainly a wrapper around driver_register().
419 */
420 int ccwgroup_driver_register(struct ccwgroup_driver *cdriver)
421 {
422 /* register our new driver with the core */
423 cdriver->driver.bus = &ccwgroup_bus_type;
424 cdriver->driver.name = cdriver->name;
425 cdriver->driver.owner = cdriver->owner;
426
427 return driver_register(&cdriver->driver);
428 }
429
430 static int
431 __ccwgroup_match_all(struct device *dev, void *data)
432 {
433 return 1;
434 }
435
436 /**
437 * ccwgroup_driver_unregister() - deregister a ccw group driver
438 * @cdriver: driver to be deregistered
439 *
440 * This function is mainly a wrapper around driver_unregister().
441 */
442 void ccwgroup_driver_unregister(struct ccwgroup_driver *cdriver)
443 {
444 struct device *dev;
445
446 /* We don't want ccwgroup devices to live longer than their driver. */
447 get_driver(&cdriver->driver);
448 while ((dev = driver_find_device(&cdriver->driver, NULL, NULL,
449 __ccwgroup_match_all))) {
450 struct ccwgroup_device *gdev = to_ccwgroupdev(dev);
451
452 mutex_lock(&gdev->reg_mutex);
453 __ccwgroup_remove_symlinks(gdev);
454 device_unregister(dev);
455 mutex_unlock(&gdev->reg_mutex);
456 put_device(dev);
457 }
458 put_driver(&cdriver->driver);
459 driver_unregister(&cdriver->driver);
460 }
461
462 /**
463 * ccwgroup_probe_ccwdev() - probe function for slave devices
464 * @cdev: ccw device to be probed
465 *
466 * This is a dummy probe function for ccw devices that are slave devices in
467 * a ccw group device.
468 * Returns:
469 * always %0
470 */
471 int ccwgroup_probe_ccwdev(struct ccw_device *cdev)
472 {
473 return 0;
474 }
475
476 static struct ccwgroup_device *
477 __ccwgroup_get_gdev_by_cdev(struct ccw_device *cdev)
478 {
479 struct ccwgroup_device *gdev;
480
481 gdev = dev_get_drvdata(&cdev->dev);
482 if (gdev) {
483 if (get_device(&gdev->dev)) {
484 mutex_lock(&gdev->reg_mutex);
485 if (device_is_registered(&gdev->dev))
486 return gdev;
487 mutex_unlock(&gdev->reg_mutex);
488 put_device(&gdev->dev);
489 }
490 return NULL;
491 }
492 return NULL;
493 }
494
495 /**
496 * ccwgroup_remove_ccwdev() - remove function for slave devices
497 * @cdev: ccw device to be removed
498 *
499 * This is a remove function for ccw devices that are slave devices in a ccw
500 * group device. It sets the ccw device offline and also deregisters the
501 * embedding ccw group device.
502 */
503 void ccwgroup_remove_ccwdev(struct ccw_device *cdev)
504 {
505 struct ccwgroup_device *gdev;
506
507 /* Ignore offlining errors, device is gone anyway. */
508 ccw_device_set_offline(cdev);
509 /* If one of its devices is gone, the whole group is done for. */
510 gdev = __ccwgroup_get_gdev_by_cdev(cdev);
511 if (gdev) {
512 __ccwgroup_remove_symlinks(gdev);
513 device_unregister(&gdev->dev);
514 mutex_unlock(&gdev->reg_mutex);
515 put_device(&gdev->dev);
516 }
517 }
518
519 MODULE_LICENSE("GPL");
520 EXPORT_SYMBOL(ccwgroup_driver_register);
521 EXPORT_SYMBOL(ccwgroup_driver_unregister);
522 EXPORT_SYMBOL(ccwgroup_create);
523 EXPORT_SYMBOL(ccwgroup_probe_ccwdev);
524 EXPORT_SYMBOL(ccwgroup_remove_ccwdev);
525
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