Pull bugzilla-3774 into release branch
[linux-2.6] / drivers / s390 / cio / ccwgroup.c
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 = container_of(dev, struct ccwgroup_device, dev);
39         gdrv = container_of(drv, struct ccwgroup_driver, driver);
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, char **envp, int num_envp, char *buffer,
48                   int buffer_size)
49 {
50         /* TODO */
51         return 0;
52 }
53
54 static struct bus_type ccwgroup_bus_type;
55
56 static void
57 __ccwgroup_remove_symlinks(struct ccwgroup_device *gdev)
58 {
59         int i;
60         char str[8];
61
62         for (i = 0; i < gdev->count; i++) {
63                 sprintf(str, "cdev%d", i);
64                 sysfs_remove_link(&gdev->dev.kobj, str);
65                 sysfs_remove_link(&gdev->cdev[i]->dev.kobj, "group_device");
66         }
67         
68 }
69
70 /*
71  * Provide an 'ungroup' attribute so the user can remove group devices no
72  * longer needed or accidentially created. Saves memory :)
73  */
74 static void ccwgroup_ungroup_callback(struct device *dev)
75 {
76         struct ccwgroup_device *gdev = to_ccwgroupdev(dev);
77
78         mutex_lock(&gdev->reg_mutex);
79         __ccwgroup_remove_symlinks(gdev);
80         device_unregister(dev);
81         mutex_unlock(&gdev->reg_mutex);
82 }
83
84 static ssize_t
85 ccwgroup_ungroup_store(struct device *dev, struct device_attribute *attr, const char *buf, size_t count)
86 {
87         struct ccwgroup_device *gdev;
88         int rc;
89
90         gdev = to_ccwgroupdev(dev);
91
92         if (gdev->state != CCWGROUP_OFFLINE)
93                 return -EINVAL;
94
95         /* Note that we cannot unregister the device from one of its
96          * attribute methods, so we have to use this roundabout approach.
97          */
98         rc = device_schedule_callback(dev, ccwgroup_ungroup_callback);
99         if (rc)
100                 count = rc;
101         return count;
102 }
103
104 static DEVICE_ATTR(ungroup, 0200, NULL, ccwgroup_ungroup_store);
105
106 static void
107 ccwgroup_release (struct device *dev)
108 {
109         struct ccwgroup_device *gdev;
110         int i;
111
112         gdev = to_ccwgroupdev(dev);
113
114         for (i = 0; i < gdev->count; i++) {
115                 gdev->cdev[i]->dev.driver_data = NULL;
116                 put_device(&gdev->cdev[i]->dev);
117         }
118         kfree(gdev);
119 }
120
121 static int
122 __ccwgroup_create_symlinks(struct ccwgroup_device *gdev)
123 {
124         char str[8];
125         int i, rc;
126
127         for (i = 0; i < gdev->count; i++) {
128                 rc = sysfs_create_link(&gdev->cdev[i]->dev.kobj, &gdev->dev.kobj,
129                                        "group_device");
130                 if (rc) {
131                         for (--i; i >= 0; i--)
132                                 sysfs_remove_link(&gdev->cdev[i]->dev.kobj,
133                                                   "group_device");
134                         return rc;
135                 }
136         }
137         for (i = 0; i < gdev->count; i++) {
138                 sprintf(str, "cdev%d", i);
139                 rc = sysfs_create_link(&gdev->dev.kobj, &gdev->cdev[i]->dev.kobj,
140                                        str);
141                 if (rc) {
142                         for (--i; i >= 0; i--) {
143                                 sprintf(str, "cdev%d", i);
144                                 sysfs_remove_link(&gdev->dev.kobj, str);
145                         }
146                         for (i = 0; i < gdev->count; i++)
147                                 sysfs_remove_link(&gdev->cdev[i]->dev.kobj,
148                                                   "group_device");
149                         return rc;
150                 }
151         }
152         return 0;
153 }
154
155 /*
156  * try to add a new ccwgroup device for one driver
157  * argc and argv[] are a list of bus_id's of devices
158  * belonging to the driver.
159  */
160 int
161 ccwgroup_create(struct device *root,
162                 unsigned int creator_id,
163                 struct ccw_driver *cdrv,
164                 int argc, char *argv[])
165 {
166         struct ccwgroup_device *gdev;
167         int i;
168         int rc;
169
170         if (argc > 256) /* disallow dumb users */
171                 return -EINVAL;
172
173         gdev = kzalloc(sizeof(*gdev) + argc*sizeof(gdev->cdev[0]), GFP_KERNEL);
174         if (!gdev)
175                 return -ENOMEM;
176
177         atomic_set(&gdev->onoff, 0);
178         mutex_init(&gdev->reg_mutex);
179         mutex_lock(&gdev->reg_mutex);
180         for (i = 0; i < argc; i++) {
181                 gdev->cdev[i] = get_ccwdev_by_busid(cdrv, argv[i]);
182
183                 /* all devices have to be of the same type in
184                  * order to be grouped */
185                 if (!gdev->cdev[i]
186                     || gdev->cdev[i]->id.driver_info !=
187                     gdev->cdev[0]->id.driver_info) {
188                         rc = -EINVAL;
189                         goto error;
190                 }
191                 /* Don't allow a device to belong to more than one group. */
192                 if (gdev->cdev[i]->dev.driver_data) {
193                         rc = -EINVAL;
194                         goto error;
195                 }
196                 gdev->cdev[i]->dev.driver_data = gdev;
197         }
198
199         gdev->creator_id = creator_id;
200         gdev->count = argc;
201         gdev->dev.bus = &ccwgroup_bus_type;
202         gdev->dev.parent = root;
203         gdev->dev.release = ccwgroup_release;
204
205         snprintf (gdev->dev.bus_id, BUS_ID_SIZE, "%s",
206                         gdev->cdev[0]->dev.bus_id);
207
208         rc = device_register(&gdev->dev);
209         if (rc)
210                 goto error;
211         get_device(&gdev->dev);
212         rc = device_create_file(&gdev->dev, &dev_attr_ungroup);
213
214         if (rc) {
215                 device_unregister(&gdev->dev);
216                 goto error;
217         }
218
219         rc = __ccwgroup_create_symlinks(gdev);
220         if (!rc) {
221                 mutex_unlock(&gdev->reg_mutex);
222                 put_device(&gdev->dev);
223                 return 0;
224         }
225         device_remove_file(&gdev->dev, &dev_attr_ungroup);
226         device_unregister(&gdev->dev);
227 error:
228         for (i = 0; i < argc; i++)
229                 if (gdev->cdev[i]) {
230                         if (gdev->cdev[i]->dev.driver_data == gdev)
231                                 gdev->cdev[i]->dev.driver_data = NULL;
232                         put_device(&gdev->cdev[i]->dev);
233                 }
234         mutex_unlock(&gdev->reg_mutex);
235         put_device(&gdev->dev);
236         return rc;
237 }
238
239 static int __init
240 init_ccwgroup (void)
241 {
242         return bus_register (&ccwgroup_bus_type);
243 }
244
245 static void __exit
246 cleanup_ccwgroup (void)
247 {
248         bus_unregister (&ccwgroup_bus_type);
249 }
250
251 module_init(init_ccwgroup);
252 module_exit(cleanup_ccwgroup);
253
254 /************************** driver stuff ******************************/
255
256 static int
257 ccwgroup_set_online(struct ccwgroup_device *gdev)
258 {
259         struct ccwgroup_driver *gdrv;
260         int ret;
261
262         if (atomic_cmpxchg(&gdev->onoff, 0, 1) != 0)
263                 return -EAGAIN;
264         if (gdev->state == CCWGROUP_ONLINE) {
265                 ret = 0;
266                 goto out;
267         }
268         if (!gdev->dev.driver) {
269                 ret = -EINVAL;
270                 goto out;
271         }
272         gdrv = to_ccwgroupdrv (gdev->dev.driver);
273         if ((ret = gdrv->set_online ? gdrv->set_online(gdev) : 0))
274                 goto out;
275
276         gdev->state = CCWGROUP_ONLINE;
277  out:
278         atomic_set(&gdev->onoff, 0);
279         return ret;
280 }
281
282 static int
283 ccwgroup_set_offline(struct ccwgroup_device *gdev)
284 {
285         struct ccwgroup_driver *gdrv;
286         int ret;
287
288         if (atomic_cmpxchg(&gdev->onoff, 0, 1) != 0)
289                 return -EAGAIN;
290         if (gdev->state == CCWGROUP_OFFLINE) {
291                 ret = 0;
292                 goto out;
293         }
294         if (!gdev->dev.driver) {
295                 ret = -EINVAL;
296                 goto out;
297         }
298         gdrv = to_ccwgroupdrv (gdev->dev.driver);
299         if ((ret = gdrv->set_offline ? gdrv->set_offline(gdev) : 0))
300                 goto out;
301
302         gdev->state = CCWGROUP_OFFLINE;
303  out:
304         atomic_set(&gdev->onoff, 0);
305         return ret;
306 }
307
308 static ssize_t
309 ccwgroup_online_store (struct device *dev, struct device_attribute *attr, const char *buf, size_t count)
310 {
311         struct ccwgroup_device *gdev;
312         struct ccwgroup_driver *gdrv;
313         unsigned int value;
314         int ret;
315
316         gdev = to_ccwgroupdev(dev);
317         if (!dev->driver)
318                 return count;
319
320         gdrv = to_ccwgroupdrv (gdev->dev.driver);
321         if (!try_module_get(gdrv->owner))
322                 return -EINVAL;
323
324         value = simple_strtoul(buf, NULL, 0);
325         ret = count;
326         if (value == 1)
327                 ccwgroup_set_online(gdev);
328         else if (value == 0)
329                 ccwgroup_set_offline(gdev);
330         else
331                 ret = -EINVAL;
332         module_put(gdrv->owner);
333         return ret;
334 }
335
336 static ssize_t
337 ccwgroup_online_show (struct device *dev, struct device_attribute *attr, char *buf)
338 {
339         int online;
340
341         online = (to_ccwgroupdev(dev)->state == CCWGROUP_ONLINE);
342
343         return sprintf(buf, online ? "1\n" : "0\n");
344 }
345
346 static DEVICE_ATTR(online, 0644, ccwgroup_online_show, ccwgroup_online_store);
347
348 static int
349 ccwgroup_probe (struct device *dev)
350 {
351         struct ccwgroup_device *gdev;
352         struct ccwgroup_driver *gdrv;
353
354         int ret;
355
356         gdev = to_ccwgroupdev(dev);
357         gdrv = to_ccwgroupdrv(dev->driver);
358
359         if ((ret = device_create_file(dev, &dev_attr_online)))
360                 return ret;
361
362         ret = gdrv->probe ? gdrv->probe(gdev) : -ENODEV;
363         if (ret)
364                 device_remove_file(dev, &dev_attr_online);
365
366         return ret;
367 }
368
369 static int
370 ccwgroup_remove (struct device *dev)
371 {
372         struct ccwgroup_device *gdev;
373         struct ccwgroup_driver *gdrv;
374
375         gdev = to_ccwgroupdev(dev);
376         gdrv = to_ccwgroupdrv(dev->driver);
377
378         device_remove_file(dev, &dev_attr_online);
379
380         if (gdrv && gdrv->remove)
381                 gdrv->remove(gdev);
382         return 0;
383 }
384
385 static struct bus_type ccwgroup_bus_type = {
386         .name   = "ccwgroup",
387         .match  = ccwgroup_bus_match,
388         .uevent = ccwgroup_uevent,
389         .probe  = ccwgroup_probe,
390         .remove = ccwgroup_remove,
391 };
392
393 int
394 ccwgroup_driver_register (struct ccwgroup_driver *cdriver)
395 {
396         /* register our new driver with the core */
397         cdriver->driver.bus = &ccwgroup_bus_type;
398         cdriver->driver.name = cdriver->name;
399
400         return driver_register(&cdriver->driver);
401 }
402
403 static int
404 __ccwgroup_match_all(struct device *dev, void *data)
405 {
406         return 1;
407 }
408
409 void
410 ccwgroup_driver_unregister (struct ccwgroup_driver *cdriver)
411 {
412         struct device *dev;
413
414         /* We don't want ccwgroup devices to live longer than their driver. */
415         get_driver(&cdriver->driver);
416         while ((dev = driver_find_device(&cdriver->driver, NULL, NULL,
417                                          __ccwgroup_match_all))) {
418                 struct ccwgroup_device *gdev = to_ccwgroupdev(dev);
419
420                 mutex_lock(&gdev->reg_mutex);
421                 __ccwgroup_remove_symlinks(gdev);
422                 device_unregister(dev);
423                 mutex_unlock(&gdev->reg_mutex);
424                 put_device(dev);
425         }
426         put_driver(&cdriver->driver);
427         driver_unregister(&cdriver->driver);
428 }
429
430 int
431 ccwgroup_probe_ccwdev(struct ccw_device *cdev)
432 {
433         return 0;
434 }
435
436 static struct ccwgroup_device *
437 __ccwgroup_get_gdev_by_cdev(struct ccw_device *cdev)
438 {
439         struct ccwgroup_device *gdev;
440
441         if (cdev->dev.driver_data) {
442                 gdev = (struct ccwgroup_device *)cdev->dev.driver_data;
443                 if (get_device(&gdev->dev)) {
444                         mutex_lock(&gdev->reg_mutex);
445                         if (device_is_registered(&gdev->dev))
446                                 return gdev;
447                         mutex_unlock(&gdev->reg_mutex);
448                         put_device(&gdev->dev);
449                 }
450                 return NULL;
451         }
452         return NULL;
453 }
454
455 void
456 ccwgroup_remove_ccwdev(struct ccw_device *cdev)
457 {
458         struct ccwgroup_device *gdev;
459
460         /* Ignore offlining errors, device is gone anyway. */
461         ccw_device_set_offline(cdev);
462         /* If one of its devices is gone, the whole group is done for. */
463         gdev = __ccwgroup_get_gdev_by_cdev(cdev);
464         if (gdev) {
465                 __ccwgroup_remove_symlinks(gdev);
466                 device_unregister(&gdev->dev);
467                 mutex_unlock(&gdev->reg_mutex);
468                 put_device(&gdev->dev);
469         }
470 }
471
472 MODULE_LICENSE("GPL");
473 EXPORT_SYMBOL(ccwgroup_driver_register);
474 EXPORT_SYMBOL(ccwgroup_driver_unregister);
475 EXPORT_SYMBOL(ccwgroup_create);
476 EXPORT_SYMBOL(ccwgroup_probe_ccwdev);
477 EXPORT_SYMBOL(ccwgroup_remove_ccwdev);