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