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