git.oblomov.eu Git - linux-2.6/blob - 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
 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 = (struct device ) {
 187                 .bus = &ccwgroup_bus_type,
 188                 .parent = root,
 189                 .release = ccwgroup_release,
 190         };
 191
 192         snprintf (gdev->dev.bus_id, BUS_ID_SIZE, "%s",
 193                         gdev->cdev[0]->dev.bus_id);
 194
 195         rc = device_register(&gdev->dev);
 196
 197         if (rc)
 198                 goto free_dev;
 199         get_device(&gdev->dev);
 200         rc = device_create_file(&gdev->dev, &dev_attr_ungroup);
 201
 202         if (rc) {
 203                 device_unregister(&gdev->dev);
 204                 goto error;
 205         }
 206
 207         rc = __ccwgroup_create_symlinks(gdev);
 208         if (!rc) {
 209                 put_device(&gdev->dev);
 210                 return 0;
 211         }
 212         device_remove_file(&gdev->dev, &dev_attr_ungroup);
 213         device_unregister(&gdev->dev);
 214 error:
 215         for (i = 0; i < argc; i++)
 216                 if (gdev->cdev[i]) {
 217                         put_device(&gdev->cdev[i]->dev);
 218                         gdev->cdev[i]->dev.driver_data = NULL;
 219                 }
 220         put_device(&gdev->dev);
 221         return rc;
 222 free_dev:
 223         for (i = 0; i < argc; i++)
 224                 if (gdev->cdev[i]) {
 225                         if (gdev->cdev[i]->dev.driver_data == gdev)
 226                                 gdev->cdev[i]->dev.driver_data = NULL;
 227                         put_device(&gdev->cdev[i]->dev);
 228                 }
 229         kfree(gdev);
 230         return rc;
 231 }
 232
 233 static int __init
 234 init_ccwgroup (void)
 235 {
 236         return bus_register (&ccwgroup_bus_type);
 237 }
 238
 239 static void __exit
 240 cleanup_ccwgroup (void)
 241 {
 242         bus_unregister (&ccwgroup_bus_type);
 243 }
 244
 245 module_init(init_ccwgroup);
 246 module_exit(cleanup_ccwgroup);
 247
 248 /************************** driver stuff ******************************/
 249
 250 static int
 251 ccwgroup_set_online(struct ccwgroup_device *gdev)
 252 {
 253         struct ccwgroup_driver *gdrv;
 254         int ret;
 255
 256         if (atomic_cmpxchg(&gdev->onoff, 0, 1) != 0)
 257                 return -EAGAIN;
 258         if (gdev->state == CCWGROUP_ONLINE) {
 259                 ret = 0;
 260                 goto out;
 261         }
 262         if (!gdev->dev.driver) {
 263                 ret = -EINVAL;
 264                 goto out;
 265         }
 266         gdrv = to_ccwgroupdrv (gdev->dev.driver);
 267         if ((ret = gdrv->set_online ? gdrv->set_online(gdev) : 0))
 268                 goto out;
 269
 270         gdev->state = CCWGROUP_ONLINE;
 271  out:
 272         atomic_set(&gdev->onoff, 0);
 273         return ret;
 274 }
 275
 276 static int
 277 ccwgroup_set_offline(struct ccwgroup_device *gdev)
 278 {
 279         struct ccwgroup_driver *gdrv;
 280         int ret;
 281
 282         if (atomic_cmpxchg(&gdev->onoff, 0, 1) != 0)
 283                 return -EAGAIN;
 284         if (gdev->state == CCWGROUP_OFFLINE) {
 285                 ret = 0;
 286                 goto out;
 287         }
 288         if (!gdev->dev.driver) {
 289                 ret = -EINVAL;
 290                 goto out;
 291         }
 292         gdrv = to_ccwgroupdrv (gdev->dev.driver);
 293         if ((ret = gdrv->set_offline ? gdrv->set_offline(gdev) : 0))
 294                 goto out;
 295
 296         gdev->state = CCWGROUP_OFFLINE;
 297  out:
 298         atomic_set(&gdev->onoff, 0);
 299         return ret;
 300 }
 301
 302 static ssize_t
 303 ccwgroup_online_store (struct device *dev, struct device_attribute *attr, const char *buf, size_t count)
 304 {
 305         struct ccwgroup_device *gdev;
 306         struct ccwgroup_driver *gdrv;
 307         unsigned int value;
 308         int ret;
 309
 310         gdev = to_ccwgroupdev(dev);
 311         if (!dev->driver)
 312                 return count;
 313
 314         gdrv = to_ccwgroupdrv (gdev->dev.driver);
 315         if (!try_module_get(gdrv->owner))
 316                 return -EINVAL;
 317
 318         value = simple_strtoul(buf, NULL, 0);
 319         ret = count;
 320         if (value == 1)
 321                 ccwgroup_set_online(gdev);
 322         else if (value == 0)
 323                 ccwgroup_set_offline(gdev);
 324         else
 325                 ret = -EINVAL;
 326         module_put(gdrv->owner);
 327         return ret;
 328 }
 329
 330 static ssize_t
 331 ccwgroup_online_show (struct device *dev, struct device_attribute *attr, char *buf)
 332 {
 333         int online;
 334
 335         online = (to_ccwgroupdev(dev)->state == CCWGROUP_ONLINE);
 336
 337         return sprintf(buf, online ? "1\n" : "0\n");
 338 }
 339
 340 static DEVICE_ATTR(online, 0644, ccwgroup_online_show, ccwgroup_online_store);
 341
 342 static int
 343 ccwgroup_probe (struct device *dev)
 344 {
 345         struct ccwgroup_device *gdev;
 346         struct ccwgroup_driver *gdrv;
 347
 348         int ret;
 349
 350         gdev = to_ccwgroupdev(dev);
 351         gdrv = to_ccwgroupdrv(dev->driver);
 352
 353         if ((ret = device_create_file(dev, &dev_attr_online)))
 354                 return ret;
 355
 356         pr_debug("%s: device %s\n", __func__, gdev->dev.bus_id);
 357         ret = gdrv->probe ? gdrv->probe(gdev) : -ENODEV;
 358         if (ret)
 359                 device_remove_file(dev, &dev_attr_online);
 360
 361         return ret;
 362 }
 363
 364 static int
 365 ccwgroup_remove (struct device *dev)
 366 {
 367         struct ccwgroup_device *gdev;
 368         struct ccwgroup_driver *gdrv;
 369
 370         gdev = to_ccwgroupdev(dev);
 371         gdrv = to_ccwgroupdrv(dev->driver);
 372
 373         pr_debug("%s: device %s\n", __func__, gdev->dev.bus_id);
 374
 375         device_remove_file(dev, &dev_attr_online);
 376
 377         if (gdrv && gdrv->remove)
 378                 gdrv->remove(gdev);
 379         return 0;
 380 }
 381
 382 static struct bus_type ccwgroup_bus_type = {
 383         .name   = "ccwgroup",
 384         .match  = ccwgroup_bus_match,
 385         .uevent = ccwgroup_uevent,
 386         .probe  = ccwgroup_probe,
 387         .remove = ccwgroup_remove,
 388 };
 389
 390 int
 391 ccwgroup_driver_register (struct ccwgroup_driver *cdriver)
 392 {
 393         /* register our new driver with the core */
 394         cdriver->driver = (struct device_driver) {
 395                 .bus = &ccwgroup_bus_type,
 396                 .name = cdriver->name,
 397         };
 398
 399         return driver_register(&cdriver->driver);
 400 }
 401
 402 static int
 403 __ccwgroup_match_all(struct device *dev, void *data)
 404 {
 405         return 1;
 406 }
 407
 408 void
 409 ccwgroup_driver_unregister (struct ccwgroup_driver *cdriver)
 410 {
 411         struct device *dev;
 412
 413         /* We don't want ccwgroup devices to live longer than their driver. */
 414         get_driver(&cdriver->driver);
 415         while ((dev = driver_find_device(&cdriver->driver, NULL, NULL,
 416                                          __ccwgroup_match_all))) {
 417                 __ccwgroup_remove_symlinks(to_ccwgroupdev(dev));
 418                 device_unregister(dev);
 419                 put_device(dev);
 420         }
 421         put_driver(&cdriver->driver);
 422         driver_unregister(&cdriver->driver);
 423 }
 424
 425 int
 426 ccwgroup_probe_ccwdev(struct ccw_device *cdev)
 427 {
 428         return 0;
 429 }
 430
 431 static inline struct ccwgroup_device *
 432 __ccwgroup_get_gdev_by_cdev(struct ccw_device *cdev)
 433 {
 434         struct ccwgroup_device *gdev;
 435
 436         if (cdev->dev.driver_data) {
 437                 gdev = (struct ccwgroup_device *)cdev->dev.driver_data;
 438                 if (get_device(&gdev->dev)) {
 439                         if (device_is_registered(&gdev->dev))
 440                                 return gdev;
 441                         put_device(&gdev->dev);
 442                 }
 443                 return NULL;
 444         }
 445         return NULL;
 446 }
 447
 448 void
 449 ccwgroup_remove_ccwdev(struct ccw_device *cdev)
 450 {
 451         struct ccwgroup_device *gdev;
 452
 453         /* Ignore offlining errors, device is gone anyway. */
 454         ccw_device_set_offline(cdev);
 455         /* If one of its devices is gone, the whole group is done for. */
 456         gdev = __ccwgroup_get_gdev_by_cdev(cdev);
 457         if (gdev) {
 458                 __ccwgroup_remove_symlinks(gdev);
 459                 device_unregister(&gdev->dev);
 460                 put_device(&gdev->dev);
 461         }
 462 }
 463
 464 MODULE_LICENSE("GPL");
 465 EXPORT_SYMBOL(ccwgroup_driver_register);
 466 EXPORT_SYMBOL(ccwgroup_driver_unregister);
 467 EXPORT_SYMBOL(ccwgroup_create);
 468 EXPORT_SYMBOL(ccwgroup_probe_ccwdev);
 469 EXPORT_SYMBOL(ccwgroup_remove_ccwdev);