Merge branch 'master' of git://git.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/ccwdev.h>
20 #include <asm/ccwgroup.h>
21
22 #define CCW_BUS_ID_SIZE         20
23
24 /* In Linux 2.4, we had a channel device layer called "chandev"
25  * that did all sorts of obscure stuff for networking devices.
26  * This is another driver that serves as a replacement for just
27  * one of its functions, namely the translation of single subchannels
28  * to devices that use multiple subchannels.
29  */
30
31 /* a device matches a driver if all its slave devices match the same
32  * entry of the driver */
33 static int
34 ccwgroup_bus_match (struct device * dev, struct device_driver * drv)
35 {
36         struct ccwgroup_device *gdev;
37         struct ccwgroup_driver *gdrv;
38
39         gdev = to_ccwgroupdev(dev);
40         gdrv = to_ccwgroupdrv(drv);
41
42         if (gdev->creator_id == gdrv->driver_id)
43                 return 1;
44
45         return 0;
46 }
47 static int
48 ccwgroup_uevent (struct device *dev, struct kobj_uevent_env *env)
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         if (device_is_registered(&gdev->dev)) {
80                 __ccwgroup_remove_symlinks(gdev);
81                 device_unregister(dev);
82         }
83         mutex_unlock(&gdev->reg_mutex);
84 }
85
86 static ssize_t
87 ccwgroup_ungroup_store(struct device *dev, struct device_attribute *attr, const char *buf, size_t count)
88 {
89         struct ccwgroup_device *gdev;
90         int rc;
91
92         gdev = to_ccwgroupdev(dev);
93
94         /* Prevent concurrent online/offline processing and ungrouping. */
95         if (atomic_cmpxchg(&gdev->onoff, 0, 1) != 0)
96                 return -EAGAIN;
97         if (gdev->state != CCWGROUP_OFFLINE) {
98                 rc = -EINVAL;
99                 goto out;
100         }
101         /* Note that we cannot unregister the device from one of its
102          * attribute methods, so we have to use this roundabout approach.
103          */
104         rc = device_schedule_callback(dev, ccwgroup_ungroup_callback);
105 out:
106         if (rc) {
107                 if (rc != -EAGAIN)
108                         /* Release onoff "lock" when ungrouping failed. */
109                         atomic_set(&gdev->onoff, 0);
110                 return rc;
111         }
112         return count;
113 }
114
115 static DEVICE_ATTR(ungroup, 0200, NULL, ccwgroup_ungroup_store);
116
117 static void
118 ccwgroup_release (struct device *dev)
119 {
120         struct ccwgroup_device *gdev;
121         int i;
122
123         gdev = to_ccwgroupdev(dev);
124
125         for (i = 0; i < gdev->count; i++) {
126                 if (gdev->cdev[i]) {
127                         if (dev_get_drvdata(&gdev->cdev[i]->dev) == gdev)
128                                 dev_set_drvdata(&gdev->cdev[i]->dev, NULL);
129                         put_device(&gdev->cdev[i]->dev);
130                 }
131         }
132         kfree(gdev);
133 }
134
135 static int
136 __ccwgroup_create_symlinks(struct ccwgroup_device *gdev)
137 {
138         char str[8];
139         int i, rc;
140
141         for (i = 0; i < gdev->count; i++) {
142                 rc = sysfs_create_link(&gdev->cdev[i]->dev.kobj, &gdev->dev.kobj,
143                                        "group_device");
144                 if (rc) {
145                         for (--i; i >= 0; i--)
146                                 sysfs_remove_link(&gdev->cdev[i]->dev.kobj,
147                                                   "group_device");
148                         return rc;
149                 }
150         }
151         for (i = 0; i < gdev->count; i++) {
152                 sprintf(str, "cdev%d", i);
153                 rc = sysfs_create_link(&gdev->dev.kobj, &gdev->cdev[i]->dev.kobj,
154                                        str);
155                 if (rc) {
156                         for (--i; i >= 0; i--) {
157                                 sprintf(str, "cdev%d", i);
158                                 sysfs_remove_link(&gdev->dev.kobj, str);
159                         }
160                         for (i = 0; i < gdev->count; i++)
161                                 sysfs_remove_link(&gdev->cdev[i]->dev.kobj,
162                                                   "group_device");
163                         return rc;
164                 }
165         }
166         return 0;
167 }
168
169 static int __get_next_bus_id(const char **buf, char *bus_id)
170 {
171         int rc, len;
172         char *start, *end;
173
174         start = (char *)*buf;
175         end = strchr(start, ',');
176         if (!end) {
177                 /* Last entry. Strip trailing newline, if applicable. */
178                 end = strchr(start, '\n');
179                 if (end)
180                         *end = '\0';
181                 len = strlen(start) + 1;
182         } else {
183                 len = end - start + 1;
184                 end++;
185         }
186         if (len < CCW_BUS_ID_SIZE) {
187                 strlcpy(bus_id, start, len);
188                 rc = 0;
189         } else
190                 rc = -EINVAL;
191         *buf = end;
192         return rc;
193 }
194
195 static int __is_valid_bus_id(char bus_id[CCW_BUS_ID_SIZE])
196 {
197         int cssid, ssid, devno;
198
199         /* Must be of form %x.%x.%04x */
200         if (sscanf(bus_id, "%x.%1x.%04x", &cssid, &ssid, &devno) != 3)
201                 return 0;
202         return 1;
203 }
204
205 /**
206  * ccwgroup_create_from_string() - create and register a ccw group device
207  * @root: parent device for the new device
208  * @creator_id: identifier of creating driver
209  * @cdrv: ccw driver of slave devices
210  * @num_devices: number of slave devices
211  * @buf: buffer containing comma separated bus ids of slave devices
212  *
213  * Create and register a new ccw group device as a child of @root. Slave
214  * devices are obtained from the list of bus ids given in @buf and must all
215  * belong to @cdrv.
216  * Returns:
217  *  %0 on success and an error code on failure.
218  * Context:
219  *  non-atomic
220  */
221 int ccwgroup_create_from_string(struct device *root, unsigned int creator_id,
222                                 struct ccw_driver *cdrv, int num_devices,
223                                 const char *buf)
224 {
225         struct ccwgroup_device *gdev;
226         int rc, i;
227         char tmp_bus_id[CCW_BUS_ID_SIZE];
228         const char *curr_buf;
229
230         gdev = kzalloc(sizeof(*gdev) + num_devices * sizeof(gdev->cdev[0]),
231                        GFP_KERNEL);
232         if (!gdev)
233                 return -ENOMEM;
234
235         atomic_set(&gdev->onoff, 0);
236         mutex_init(&gdev->reg_mutex);
237         mutex_lock(&gdev->reg_mutex);
238         gdev->creator_id = creator_id;
239         gdev->count = num_devices;
240         gdev->dev.bus = &ccwgroup_bus_type;
241         gdev->dev.parent = root;
242         gdev->dev.release = ccwgroup_release;
243         device_initialize(&gdev->dev);
244
245         curr_buf = buf;
246         for (i = 0; i < num_devices && curr_buf; i++) {
247                 rc = __get_next_bus_id(&curr_buf, tmp_bus_id);
248                 if (rc != 0)
249                         goto error;
250                 if (!__is_valid_bus_id(tmp_bus_id)) {
251                         rc = -EINVAL;
252                         goto error;
253                 }
254                 gdev->cdev[i] = get_ccwdev_by_busid(cdrv, tmp_bus_id);
255                 /*
256                  * All devices have to be of the same type in
257                  * order to be grouped.
258                  */
259                 if (!gdev->cdev[i]
260                     || gdev->cdev[i]->id.driver_info !=
261                     gdev->cdev[0]->id.driver_info) {
262                         rc = -EINVAL;
263                         goto error;
264                 }
265                 /* Don't allow a device to belong to more than one group. */
266                 if (dev_get_drvdata(&gdev->cdev[i]->dev)) {
267                         rc = -EINVAL;
268                         goto error;
269                 }
270                 dev_set_drvdata(&gdev->cdev[i]->dev, gdev);
271         }
272         /* Check for sufficient number of bus ids. */
273         if (i < num_devices && !curr_buf) {
274                 rc = -EINVAL;
275                 goto error;
276         }
277         /* Check for trailing stuff. */
278         if (i == num_devices && strlen(curr_buf) > 0) {
279                 rc = -EINVAL;
280                 goto error;
281         }
282
283         dev_set_name(&gdev->dev, "%s", dev_name(&gdev->cdev[0]->dev));
284
285         rc = device_add(&gdev->dev);
286         if (rc)
287                 goto error;
288         get_device(&gdev->dev);
289         rc = device_create_file(&gdev->dev, &dev_attr_ungroup);
290
291         if (rc) {
292                 device_unregister(&gdev->dev);
293                 goto error;
294         }
295
296         rc = __ccwgroup_create_symlinks(gdev);
297         if (!rc) {
298                 mutex_unlock(&gdev->reg_mutex);
299                 put_device(&gdev->dev);
300                 return 0;
301         }
302         device_remove_file(&gdev->dev, &dev_attr_ungroup);
303         device_unregister(&gdev->dev);
304 error:
305         for (i = 0; i < num_devices; i++)
306                 if (gdev->cdev[i]) {
307                         if (dev_get_drvdata(&gdev->cdev[i]->dev) == gdev)
308                                 dev_set_drvdata(&gdev->cdev[i]->dev, NULL);
309                         put_device(&gdev->cdev[i]->dev);
310                         gdev->cdev[i] = NULL;
311                 }
312         mutex_unlock(&gdev->reg_mutex);
313         put_device(&gdev->dev);
314         return rc;
315 }
316 EXPORT_SYMBOL(ccwgroup_create_from_string);
317
318 static int ccwgroup_notifier(struct notifier_block *nb, unsigned long action,
319                              void *data);
320
321 static struct notifier_block ccwgroup_nb = {
322         .notifier_call = ccwgroup_notifier
323 };
324
325 static int __init init_ccwgroup(void)
326 {
327         int ret;
328
329         ret = bus_register(&ccwgroup_bus_type);
330         if (ret)
331                 return ret;
332
333         ret = bus_register_notifier(&ccwgroup_bus_type, &ccwgroup_nb);
334         if (ret)
335                 bus_unregister(&ccwgroup_bus_type);
336
337         return ret;
338 }
339
340 static void __exit cleanup_ccwgroup(void)
341 {
342         bus_unregister_notifier(&ccwgroup_bus_type, &ccwgroup_nb);
343         bus_unregister(&ccwgroup_bus_type);
344 }
345
346 module_init(init_ccwgroup);
347 module_exit(cleanup_ccwgroup);
348
349 /************************** driver stuff ******************************/
350
351 static int
352 ccwgroup_set_online(struct ccwgroup_device *gdev)
353 {
354         struct ccwgroup_driver *gdrv;
355         int ret;
356
357         if (atomic_cmpxchg(&gdev->onoff, 0, 1) != 0)
358                 return -EAGAIN;
359         if (gdev->state == CCWGROUP_ONLINE) {
360                 ret = 0;
361                 goto out;
362         }
363         if (!gdev->dev.driver) {
364                 ret = -EINVAL;
365                 goto out;
366         }
367         gdrv = to_ccwgroupdrv (gdev->dev.driver);
368         if ((ret = gdrv->set_online ? gdrv->set_online(gdev) : 0))
369                 goto out;
370
371         gdev->state = CCWGROUP_ONLINE;
372  out:
373         atomic_set(&gdev->onoff, 0);
374         return ret;
375 }
376
377 static int
378 ccwgroup_set_offline(struct ccwgroup_device *gdev)
379 {
380         struct ccwgroup_driver *gdrv;
381         int ret;
382
383         if (atomic_cmpxchg(&gdev->onoff, 0, 1) != 0)
384                 return -EAGAIN;
385         if (gdev->state == CCWGROUP_OFFLINE) {
386                 ret = 0;
387                 goto out;
388         }
389         if (!gdev->dev.driver) {
390                 ret = -EINVAL;
391                 goto out;
392         }
393         gdrv = to_ccwgroupdrv (gdev->dev.driver);
394         if ((ret = gdrv->set_offline ? gdrv->set_offline(gdev) : 0))
395                 goto out;
396
397         gdev->state = CCWGROUP_OFFLINE;
398  out:
399         atomic_set(&gdev->onoff, 0);
400         return ret;
401 }
402
403 static ssize_t
404 ccwgroup_online_store (struct device *dev, struct device_attribute *attr, const char *buf, size_t count)
405 {
406         struct ccwgroup_device *gdev;
407         struct ccwgroup_driver *gdrv;
408         unsigned long value;
409         int ret;
410
411         if (!dev->driver)
412                 return -ENODEV;
413
414         gdev = to_ccwgroupdev(dev);
415         gdrv = to_ccwgroupdrv(dev->driver);
416
417         if (!try_module_get(gdrv->owner))
418                 return -EINVAL;
419
420         ret = strict_strtoul(buf, 0, &value);
421         if (ret)
422                 goto out;
423
424         if (value == 1)
425                 ret = ccwgroup_set_online(gdev);
426         else if (value == 0)
427                 ret = ccwgroup_set_offline(gdev);
428         else
429                 ret = -EINVAL;
430 out:
431         module_put(gdrv->owner);
432         return (ret == 0) ? count : ret;
433 }
434
435 static ssize_t
436 ccwgroup_online_show (struct device *dev, struct device_attribute *attr, char *buf)
437 {
438         int online;
439
440         online = (to_ccwgroupdev(dev)->state == CCWGROUP_ONLINE);
441
442         return sprintf(buf, online ? "1\n" : "0\n");
443 }
444
445 static DEVICE_ATTR(online, 0644, ccwgroup_online_show, ccwgroup_online_store);
446
447 static int
448 ccwgroup_probe (struct device *dev)
449 {
450         struct ccwgroup_device *gdev;
451         struct ccwgroup_driver *gdrv;
452
453         int ret;
454
455         gdev = to_ccwgroupdev(dev);
456         gdrv = to_ccwgroupdrv(dev->driver);
457
458         if ((ret = device_create_file(dev, &dev_attr_online)))
459                 return ret;
460
461         ret = gdrv->probe ? gdrv->probe(gdev) : -ENODEV;
462         if (ret)
463                 device_remove_file(dev, &dev_attr_online);
464
465         return ret;
466 }
467
468 static int
469 ccwgroup_remove (struct device *dev)
470 {
471         struct ccwgroup_device *gdev;
472         struct ccwgroup_driver *gdrv;
473
474         device_remove_file(dev, &dev_attr_online);
475         device_remove_file(dev, &dev_attr_ungroup);
476
477         if (!dev->driver)
478                 return 0;
479
480         gdev = to_ccwgroupdev(dev);
481         gdrv = to_ccwgroupdrv(dev->driver);
482
483         if (gdrv->remove)
484                 gdrv->remove(gdev);
485
486         return 0;
487 }
488
489 static void ccwgroup_shutdown(struct device *dev)
490 {
491         struct ccwgroup_device *gdev;
492         struct ccwgroup_driver *gdrv;
493
494         if (!dev->driver)
495                 return;
496
497         gdev = to_ccwgroupdev(dev);
498         gdrv = to_ccwgroupdrv(dev->driver);
499
500         if (gdrv->shutdown)
501                 gdrv->shutdown(gdev);
502 }
503
504 static struct bus_type ccwgroup_bus_type = {
505         .name   = "ccwgroup",
506         .match  = ccwgroup_bus_match,
507         .uevent = ccwgroup_uevent,
508         .probe  = ccwgroup_probe,
509         .remove = ccwgroup_remove,
510         .shutdown = ccwgroup_shutdown,
511 };
512
513
514 static int ccwgroup_notifier(struct notifier_block *nb, unsigned long action,
515                              void *data)
516 {
517         struct device *dev = data;
518
519         if (action == BUS_NOTIFY_UNBIND_DRIVER)
520                 device_schedule_callback(dev, ccwgroup_ungroup_callback);
521
522         return NOTIFY_OK;
523 }
524
525
526 /**
527  * ccwgroup_driver_register() - register a ccw group driver
528  * @cdriver: driver to be registered
529  *
530  * This function is mainly a wrapper around driver_register().
531  */
532 int ccwgroup_driver_register(struct ccwgroup_driver *cdriver)
533 {
534         /* register our new driver with the core */
535         cdriver->driver.bus = &ccwgroup_bus_type;
536         cdriver->driver.name = cdriver->name;
537         cdriver->driver.owner = cdriver->owner;
538
539         return driver_register(&cdriver->driver);
540 }
541
542 static int
543 __ccwgroup_match_all(struct device *dev, void *data)
544 {
545         return 1;
546 }
547
548 /**
549  * ccwgroup_driver_unregister() - deregister a ccw group driver
550  * @cdriver: driver to be deregistered
551  *
552  * This function is mainly a wrapper around driver_unregister().
553  */
554 void ccwgroup_driver_unregister(struct ccwgroup_driver *cdriver)
555 {
556         struct device *dev;
557
558         /* We don't want ccwgroup devices to live longer than their driver. */
559         get_driver(&cdriver->driver);
560         while ((dev = driver_find_device(&cdriver->driver, NULL, NULL,
561                                          __ccwgroup_match_all))) {
562                 struct ccwgroup_device *gdev = to_ccwgroupdev(dev);
563
564                 mutex_lock(&gdev->reg_mutex);
565                 __ccwgroup_remove_symlinks(gdev);
566                 device_unregister(dev);
567                 mutex_unlock(&gdev->reg_mutex);
568                 put_device(dev);
569         }
570         put_driver(&cdriver->driver);
571         driver_unregister(&cdriver->driver);
572 }
573
574 /**
575  * ccwgroup_probe_ccwdev() - probe function for slave devices
576  * @cdev: ccw device to be probed
577  *
578  * This is a dummy probe function for ccw devices that are slave devices in
579  * a ccw group device.
580  * Returns:
581  *  always %0
582  */
583 int ccwgroup_probe_ccwdev(struct ccw_device *cdev)
584 {
585         return 0;
586 }
587
588 static struct ccwgroup_device *
589 __ccwgroup_get_gdev_by_cdev(struct ccw_device *cdev)
590 {
591         struct ccwgroup_device *gdev;
592
593         gdev = dev_get_drvdata(&cdev->dev);
594         if (gdev) {
595                 if (get_device(&gdev->dev)) {
596                         mutex_lock(&gdev->reg_mutex);
597                         if (device_is_registered(&gdev->dev))
598                                 return gdev;
599                         mutex_unlock(&gdev->reg_mutex);
600                         put_device(&gdev->dev);
601                 }
602                 return NULL;
603         }
604         return NULL;
605 }
606
607 /**
608  * ccwgroup_remove_ccwdev() - remove function for slave devices
609  * @cdev: ccw device to be removed
610  *
611  * This is a remove function for ccw devices that are slave devices in a ccw
612  * group device. It sets the ccw device offline and also deregisters the
613  * embedding ccw group device.
614  */
615 void ccwgroup_remove_ccwdev(struct ccw_device *cdev)
616 {
617         struct ccwgroup_device *gdev;
618
619         /* Ignore offlining errors, device is gone anyway. */
620         ccw_device_set_offline(cdev);
621         /* If one of its devices is gone, the whole group is done for. */
622         gdev = __ccwgroup_get_gdev_by_cdev(cdev);
623         if (gdev) {
624                 __ccwgroup_remove_symlinks(gdev);
625                 device_unregister(&gdev->dev);
626                 mutex_unlock(&gdev->reg_mutex);
627                 put_device(&gdev->dev);
628         }
629 }
630
631 MODULE_LICENSE("GPL");
632 EXPORT_SYMBOL(ccwgroup_driver_register);
633 EXPORT_SYMBOL(ccwgroup_driver_unregister);
634 EXPORT_SYMBOL(ccwgroup_probe_ccwdev);
635 EXPORT_SYMBOL(ccwgroup_remove_ccwdev);