Merge git://git.infradead.org/mtd-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 inline 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 inline 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         int del_drvdata;
156
157         if (argc > 256) /* disallow dumb users */
158                 return -EINVAL;
159
160         gdev = kzalloc(sizeof(*gdev) + argc*sizeof(gdev->cdev[0]), GFP_KERNEL);
161         if (!gdev)
162                 return -ENOMEM;
163
164         atomic_set(&gdev->onoff, 0);
165
166         del_drvdata = 0;
167         for (i = 0; i < argc; i++) {
168                 gdev->cdev[i] = get_ccwdev_by_busid(cdrv, argv[i]);
169
170                 /* all devices have to be of the same type in
171                  * order to be grouped */
172                 if (!gdev->cdev[i]
173                     || gdev->cdev[i]->id.driver_info !=
174                     gdev->cdev[0]->id.driver_info) {
175                         rc = -EINVAL;
176                         goto free_dev;
177                 }
178                 /* Don't allow a device to belong to more than one group. */
179                 if (gdev->cdev[i]->dev.driver_data) {
180                         rc = -EINVAL;
181                         goto free_dev;
182                 }
183         }
184         for (i = 0; i < argc; i++)
185                 gdev->cdev[i]->dev.driver_data = gdev;
186         del_drvdata = 1;
187
188         gdev->creator_id = creator_id;
189         gdev->count = argc;
190         gdev->dev = (struct device ) {
191                 .bus = &ccwgroup_bus_type,
192                 .parent = root,
193                 .release = ccwgroup_release,
194         };
195
196         snprintf (gdev->dev.bus_id, BUS_ID_SIZE, "%s",
197                         gdev->cdev[0]->dev.bus_id);
198
199         rc = device_register(&gdev->dev);
200         
201         if (rc)
202                 goto free_dev;
203         get_device(&gdev->dev);
204         rc = device_create_file(&gdev->dev, &dev_attr_ungroup);
205
206         if (rc) {
207                 device_unregister(&gdev->dev);
208                 goto error;
209         }
210
211         rc = __ccwgroup_create_symlinks(gdev);
212         if (!rc) {
213                 put_device(&gdev->dev);
214                 return 0;
215         }
216         device_remove_file(&gdev->dev, &dev_attr_ungroup);
217         device_unregister(&gdev->dev);
218 error:
219         for (i = 0; i < argc; i++)
220                 if (gdev->cdev[i]) {
221                         put_device(&gdev->cdev[i]->dev);
222                         gdev->cdev[i]->dev.driver_data = NULL;
223                 }
224         put_device(&gdev->dev);
225         return rc;
226 free_dev:
227         for (i = 0; i < argc; i++)
228                 if (gdev->cdev[i]) {
229                         put_device(&gdev->cdev[i]->dev);
230                         if (del_drvdata)
231                                 gdev->cdev[i]->dev.driver_data = NULL;
232                 }
233         kfree(gdev);
234         return rc;
235 }
236
237 static int __init
238 init_ccwgroup (void)
239 {
240         return bus_register (&ccwgroup_bus_type);
241 }
242
243 static void __exit
244 cleanup_ccwgroup (void)
245 {
246         bus_unregister (&ccwgroup_bus_type);
247 }
248
249 module_init(init_ccwgroup);
250 module_exit(cleanup_ccwgroup);
251
252 /************************** driver stuff ******************************/
253
254 static int
255 ccwgroup_set_online(struct ccwgroup_device *gdev)
256 {
257         struct ccwgroup_driver *gdrv;
258         int ret;
259
260         if (atomic_cmpxchg(&gdev->onoff, 0, 1) != 0)
261                 return -EAGAIN;
262         if (gdev->state == CCWGROUP_ONLINE) {
263                 ret = 0;
264                 goto out;
265         }
266         if (!gdev->dev.driver) {
267                 ret = -EINVAL;
268                 goto out;
269         }
270         gdrv = to_ccwgroupdrv (gdev->dev.driver);
271         if ((ret = gdrv->set_online ? gdrv->set_online(gdev) : 0))
272                 goto out;
273
274         gdev->state = CCWGROUP_ONLINE;
275  out:
276         atomic_set(&gdev->onoff, 0);
277         return ret;
278 }
279
280 static int
281 ccwgroup_set_offline(struct ccwgroup_device *gdev)
282 {
283         struct ccwgroup_driver *gdrv;
284         int ret;
285
286         if (atomic_cmpxchg(&gdev->onoff, 0, 1) != 0)
287                 return -EAGAIN;
288         if (gdev->state == CCWGROUP_OFFLINE) {
289                 ret = 0;
290                 goto out;
291         }
292         if (!gdev->dev.driver) {
293                 ret = -EINVAL;
294                 goto out;
295         }
296         gdrv = to_ccwgroupdrv (gdev->dev.driver);
297         if ((ret = gdrv->set_offline ? gdrv->set_offline(gdev) : 0))
298                 goto out;
299
300         gdev->state = CCWGROUP_OFFLINE;
301  out:
302         atomic_set(&gdev->onoff, 0);
303         return ret;
304 }
305
306 static ssize_t
307 ccwgroup_online_store (struct device *dev, struct device_attribute *attr, const char *buf, size_t count)
308 {
309         struct ccwgroup_device *gdev;
310         struct ccwgroup_driver *gdrv;
311         unsigned int value;
312         int ret;
313
314         gdev = to_ccwgroupdev(dev);
315         if (!dev->driver)
316                 return count;
317
318         gdrv = to_ccwgroupdrv (gdev->dev.driver);
319         if (!try_module_get(gdrv->owner))
320                 return -EINVAL;
321
322         value = simple_strtoul(buf, 0, 0);
323         ret = count;
324         if (value == 1)
325                 ccwgroup_set_online(gdev);
326         else if (value == 0)
327                 ccwgroup_set_offline(gdev);
328         else
329                 ret = -EINVAL;
330         module_put(gdrv->owner);
331         return ret;
332 }
333
334 static ssize_t
335 ccwgroup_online_show (struct device *dev, struct device_attribute *attr, char *buf)
336 {
337         int online;
338
339         online = (to_ccwgroupdev(dev)->state == CCWGROUP_ONLINE);
340
341         return sprintf(buf, online ? "1\n" : "0\n");
342 }
343
344 static DEVICE_ATTR(online, 0644, ccwgroup_online_show, ccwgroup_online_store);
345
346 static int
347 ccwgroup_probe (struct device *dev)
348 {
349         struct ccwgroup_device *gdev;
350         struct ccwgroup_driver *gdrv;
351
352         int ret;
353
354         gdev = to_ccwgroupdev(dev);
355         gdrv = to_ccwgroupdrv(dev->driver);
356
357         if ((ret = device_create_file(dev, &dev_attr_online)))
358                 return ret;
359
360         pr_debug("%s: device %s\n", __func__, gdev->dev.bus_id);
361         ret = gdrv->probe ? gdrv->probe(gdev) : -ENODEV;
362         if (ret)
363                 device_remove_file(dev, &dev_attr_online);
364
365         return ret;
366 }
367
368 static int
369 ccwgroup_remove (struct device *dev)
370 {
371         struct ccwgroup_device *gdev;
372         struct ccwgroup_driver *gdrv;
373
374         gdev = to_ccwgroupdev(dev);
375         gdrv = to_ccwgroupdrv(dev->driver);
376
377         pr_debug("%s: device %s\n", __func__, gdev->dev.bus_id);
378
379         device_remove_file(dev, &dev_attr_online);
380
381         if (gdrv && gdrv->remove)
382                 gdrv->remove(gdev);
383         return 0;
384 }
385
386 static struct bus_type ccwgroup_bus_type = {
387         .name   = "ccwgroup",
388         .match  = ccwgroup_bus_match,
389         .uevent = ccwgroup_uevent,
390         .probe  = ccwgroup_probe,
391         .remove = ccwgroup_remove,
392 };
393
394 int
395 ccwgroup_driver_register (struct ccwgroup_driver *cdriver)
396 {
397         /* register our new driver with the core */
398         cdriver->driver = (struct device_driver) {
399                 .bus = &ccwgroup_bus_type,
400                 .name = cdriver->name,
401         };
402
403         return driver_register(&cdriver->driver);
404 }
405
406 static int
407 __ccwgroup_match_all(struct device *dev, void *data)
408 {
409         return 1;
410 }
411
412 void
413 ccwgroup_driver_unregister (struct ccwgroup_driver *cdriver)
414 {
415         struct device *dev;
416
417         /* We don't want ccwgroup devices to live longer than their driver. */
418         get_driver(&cdriver->driver);
419         while ((dev = driver_find_device(&cdriver->driver, NULL, NULL,
420                                          __ccwgroup_match_all))) {
421                 __ccwgroup_remove_symlinks(to_ccwgroupdev(dev));
422                 device_unregister(dev);
423                 put_device(dev);
424         }
425         put_driver(&cdriver->driver);
426         driver_unregister(&cdriver->driver);
427 }
428
429 int
430 ccwgroup_probe_ccwdev(struct ccw_device *cdev)
431 {
432         return 0;
433 }
434
435 static inline struct ccwgroup_device *
436 __ccwgroup_get_gdev_by_cdev(struct ccw_device *cdev)
437 {
438         struct ccwgroup_device *gdev;
439
440         if (cdev->dev.driver_data) {
441                 gdev = (struct ccwgroup_device *)cdev->dev.driver_data;
442                 if (get_device(&gdev->dev)) {
443                         if (device_is_registered(&gdev->dev))
444                                 return gdev;
445                         put_device(&gdev->dev);
446                 }
447                 return NULL;
448         }
449         return NULL;
450 }
451
452 void
453 ccwgroup_remove_ccwdev(struct ccw_device *cdev)
454 {
455         struct ccwgroup_device *gdev;
456
457         /* Ignore offlining errors, device is gone anyway. */
458         ccw_device_set_offline(cdev);
459         /* If one of its devices is gone, the whole group is done for. */
460         gdev = __ccwgroup_get_gdev_by_cdev(cdev);
461         if (gdev) {
462                 __ccwgroup_remove_symlinks(gdev);
463                 device_unregister(&gdev->dev);
464                 put_device(&gdev->dev);
465         }
466 }
467
468 MODULE_LICENSE("GPL");
469 EXPORT_SYMBOL(ccwgroup_driver_register);
470 EXPORT_SYMBOL(ccwgroup_driver_unregister);
471 EXPORT_SYMBOL(ccwgroup_create);
472 EXPORT_SYMBOL(ccwgroup_probe_ccwdev);
473 EXPORT_SYMBOL(ccwgroup_remove_ccwdev);