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 = to_ccwgroupdev(dev);
  39         gdrv = to_ccwgroupdrv(drv);
  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         if (device_is_registered(&gdev->dev)) {
  79                 __ccwgroup_remove_symlinks(gdev);
  80                 device_unregister(dev);
  81         }
  82         mutex_unlock(&gdev->reg_mutex);
  83 }
  84
  85 static ssize_t
  86 ccwgroup_ungroup_store(struct device *dev, struct device_attribute *attr, const char *buf, size_t count)
  87 {
  88         struct ccwgroup_device *gdev;
  89         int rc;
  90
  91         gdev = to_ccwgroupdev(dev);
  92
  93         if (gdev->state != CCWGROUP_OFFLINE)
  94                 return -EINVAL;
  95
  96         /* Note that we cannot unregister the device from one of its
  97          * attribute methods, so we have to use this roundabout approach.
  98          */
  99         rc = device_schedule_callback(dev, ccwgroup_ungroup_callback);
 100         if (rc)
 101                 count = rc;
 102         return count;
 103 }
 104
 105 static DEVICE_ATTR(ungroup, 0200, NULL, ccwgroup_ungroup_store);
 106
 107 static void
 108 ccwgroup_release (struct device *dev)
 109 {
 110         struct ccwgroup_device *gdev;
 111         int i;
 112
 113         gdev = to_ccwgroupdev(dev);
 114
 115         for (i = 0; i < gdev->count; i++) {
 116                 dev_set_drvdata(&gdev->cdev[i]->dev, NULL);
 117                 put_device(&gdev->cdev[i]->dev);
 118         }
 119         kfree(gdev);
 120 }
 121
 122 static int
 123 __ccwgroup_create_symlinks(struct ccwgroup_device *gdev)
 124 {
 125         char str[8];
 126         int i, rc;
 127
 128         for (i = 0; i < gdev->count; i++) {
 129                 rc = sysfs_create_link(&gdev->cdev[i]->dev.kobj, &gdev->dev.kobj,
 130                                        "group_device");
 131                 if (rc) {
 132                         for (--i; i >= 0; i--)
 133                                 sysfs_remove_link(&gdev->cdev[i]->dev.kobj,
 134                                                   "group_device");
 135                         return rc;
 136                 }
 137         }
 138         for (i = 0; i < gdev->count; i++) {
 139                 sprintf(str, "cdev%d", i);
 140                 rc = sysfs_create_link(&gdev->dev.kobj, &gdev->cdev[i]->dev.kobj,
 141                                        str);
 142                 if (rc) {
 143                         for (--i; i >= 0; i--) {
 144                                 sprintf(str, "cdev%d", i);
 145                                 sysfs_remove_link(&gdev->dev.kobj, str);
 146                         }
 147                         for (i = 0; i < gdev->count; i++)
 148                                 sysfs_remove_link(&gdev->cdev[i]->dev.kobj,
 149                                                   "group_device");
 150                         return rc;
 151                 }
 152         }
 153         return 0;
 154 }
 155
 156 /**
 157  * ccwgroup_create() - create and register a ccw group device
 158  * @root: parent device for the new device
 159  * @creator_id: identifier of creating driver
 160  * @cdrv: ccw driver of slave devices
 161  * @argc: number of slave devices
 162  * @argv: bus ids of slave devices
 163  *
 164  * Create and register a new ccw group device as a child of @root. Slave
 165  * devices are obtained from the list of bus ids given in @argv[] and must all
 166  * belong to @cdrv.
 167  * Returns:
 168  *  %0 on success and an error code on failure.
 169  * Context:
 170  *  non-atomic
 171  */
 172 int ccwgroup_create(struct device *root, unsigned int creator_id,
 173                     struct ccw_driver *cdrv, int argc, char *argv[])
 174 {
 175         struct ccwgroup_device *gdev;
 176         int i;
 177         int rc;
 178
 179         if (argc > 256) /* disallow dumb users */
 180                 return -EINVAL;
 181
 182         gdev = kzalloc(sizeof(*gdev) + argc*sizeof(gdev->cdev[0]), GFP_KERNEL);
 183         if (!gdev)
 184                 return -ENOMEM;
 185
 186         atomic_set(&gdev->onoff, 0);
 187         mutex_init(&gdev->reg_mutex);
 188         mutex_lock(&gdev->reg_mutex);
 189         for (i = 0; i < argc; i++) {
 190                 gdev->cdev[i] = get_ccwdev_by_busid(cdrv, argv[i]);
 191
 192                 /* all devices have to be of the same type in
 193                  * order to be grouped */
 194                 if (!gdev->cdev[i]
 195                     || gdev->cdev[i]->id.driver_info !=
 196                     gdev->cdev[0]->id.driver_info) {
 197                         rc = -EINVAL;
 198                         goto error;
 199                 }
 200                 /* Don't allow a device to belong to more than one group. */
 201                 if (dev_get_drvdata(&gdev->cdev[i]->dev)) {
 202                         rc = -EINVAL;
 203                         goto error;
 204                 }
 205                 dev_set_drvdata(&gdev->cdev[i]->dev, gdev);
 206         }
 207
 208         gdev->creator_id = creator_id;
 209         gdev->count = argc;
 210         gdev->dev.bus = &ccwgroup_bus_type;
 211         gdev->dev.parent = root;
 212         gdev->dev.release = ccwgroup_release;
 213
 214         snprintf (gdev->dev.bus_id, BUS_ID_SIZE, "%s",
 215                         gdev->cdev[0]->dev.bus_id);
 216
 217         rc = device_register(&gdev->dev);
 218         if (rc)
 219                 goto error;
 220         get_device(&gdev->dev);
 221         rc = device_create_file(&gdev->dev, &dev_attr_ungroup);
 222
 223         if (rc) {
 224                 device_unregister(&gdev->dev);
 225                 goto error;
 226         }
 227
 228         rc = __ccwgroup_create_symlinks(gdev);
 229         if (!rc) {
 230                 mutex_unlock(&gdev->reg_mutex);
 231                 put_device(&gdev->dev);
 232                 return 0;
 233         }
 234         device_remove_file(&gdev->dev, &dev_attr_ungroup);
 235         device_unregister(&gdev->dev);
 236 error:
 237         for (i = 0; i < argc; i++)
 238                 if (gdev->cdev[i]) {
 239                         if (dev_get_drvdata(&gdev->cdev[i]->dev) == gdev)
 240                                 dev_set_drvdata(&gdev->cdev[i]->dev, NULL);
 241                         put_device(&gdev->cdev[i]->dev);
 242                 }
 243         mutex_unlock(&gdev->reg_mutex);
 244         put_device(&gdev->dev);
 245         return rc;
 246 }
 247
 248 static int __init
 249 init_ccwgroup (void)
 250 {
 251         return bus_register (&ccwgroup_bus_type);
 252 }
 253
 254 static void __exit
 255 cleanup_ccwgroup (void)
 256 {
 257         bus_unregister (&ccwgroup_bus_type);
 258 }
 259
 260 module_init(init_ccwgroup);
 261 module_exit(cleanup_ccwgroup);
 262
 263 /************************** driver stuff ******************************/
 264
 265 static int
 266 ccwgroup_set_online(struct ccwgroup_device *gdev)
 267 {
 268         struct ccwgroup_driver *gdrv;
 269         int ret;
 270
 271         if (atomic_cmpxchg(&gdev->onoff, 0, 1) != 0)
 272                 return -EAGAIN;
 273         if (gdev->state == CCWGROUP_ONLINE) {
 274                 ret = 0;
 275                 goto out;
 276         }
 277         if (!gdev->dev.driver) {
 278                 ret = -EINVAL;
 279                 goto out;
 280         }
 281         gdrv = to_ccwgroupdrv (gdev->dev.driver);
 282         if ((ret = gdrv->set_online ? gdrv->set_online(gdev) : 0))
 283                 goto out;
 284
 285         gdev->state = CCWGROUP_ONLINE;
 286  out:
 287         atomic_set(&gdev->onoff, 0);
 288         return ret;
 289 }
 290
 291 static int
 292 ccwgroup_set_offline(struct ccwgroup_device *gdev)
 293 {
 294         struct ccwgroup_driver *gdrv;
 295         int ret;
 296
 297         if (atomic_cmpxchg(&gdev->onoff, 0, 1) != 0)
 298                 return -EAGAIN;
 299         if (gdev->state == CCWGROUP_OFFLINE) {
 300                 ret = 0;
 301                 goto out;
 302         }
 303         if (!gdev->dev.driver) {
 304                 ret = -EINVAL;
 305                 goto out;
 306         }
 307         gdrv = to_ccwgroupdrv (gdev->dev.driver);
 308         if ((ret = gdrv->set_offline ? gdrv->set_offline(gdev) : 0))
 309                 goto out;
 310
 311         gdev->state = CCWGROUP_OFFLINE;
 312  out:
 313         atomic_set(&gdev->onoff, 0);
 314         return ret;
 315 }
 316
 317 static ssize_t
 318 ccwgroup_online_store (struct device *dev, struct device_attribute *attr, const char *buf, size_t count)
 319 {
 320         struct ccwgroup_device *gdev;
 321         struct ccwgroup_driver *gdrv;
 322         unsigned int value;
 323         int ret;
 324
 325         gdev = to_ccwgroupdev(dev);
 326         if (!dev->driver)
 327                 return count;
 328
 329         gdrv = to_ccwgroupdrv (gdev->dev.driver);
 330         if (!try_module_get(gdrv->owner))
 331                 return -EINVAL;
 332
 333         value = simple_strtoul(buf, NULL, 0);
 334         ret = count;
 335         if (value == 1)
 336                 ccwgroup_set_online(gdev);
 337         else if (value == 0)
 338                 ccwgroup_set_offline(gdev);
 339         else
 340                 ret = -EINVAL;
 341         module_put(gdrv->owner);
 342         return ret;
 343 }
 344
 345 static ssize_t
 346 ccwgroup_online_show (struct device *dev, struct device_attribute *attr, char *buf)
 347 {
 348         int online;
 349
 350         online = (to_ccwgroupdev(dev)->state == CCWGROUP_ONLINE);
 351
 352         return sprintf(buf, online ? "1\n" : "0\n");
 353 }
 354
 355 static DEVICE_ATTR(online, 0644, ccwgroup_online_show, ccwgroup_online_store);
 356
 357 static int
 358 ccwgroup_probe (struct device *dev)
 359 {
 360         struct ccwgroup_device *gdev;
 361         struct ccwgroup_driver *gdrv;
 362
 363         int ret;
 364
 365         gdev = to_ccwgroupdev(dev);
 366         gdrv = to_ccwgroupdrv(dev->driver);
 367
 368         if ((ret = device_create_file(dev, &dev_attr_online)))
 369                 return ret;
 370
 371         ret = gdrv->probe ? gdrv->probe(gdev) : -ENODEV;
 372         if (ret)
 373                 device_remove_file(dev, &dev_attr_online);
 374
 375         return ret;
 376 }
 377
 378 static int
 379 ccwgroup_remove (struct device *dev)
 380 {
 381         struct ccwgroup_device *gdev;
 382         struct ccwgroup_driver *gdrv;
 383
 384         gdev = to_ccwgroupdev(dev);
 385         gdrv = to_ccwgroupdrv(dev->driver);
 386
 387         device_remove_file(dev, &dev_attr_online);
 388
 389         if (gdrv && gdrv->remove)
 390                 gdrv->remove(gdev);
 391         return 0;
 392 }
 393
 394 static struct bus_type ccwgroup_bus_type = {
 395         .name   = "ccwgroup",
 396         .match  = ccwgroup_bus_match,
 397         .uevent = ccwgroup_uevent,
 398         .probe  = ccwgroup_probe,
 399         .remove = ccwgroup_remove,
 400 };
 401
 402 /**
 403  * ccwgroup_driver_register() - register a ccw group driver
 404  * @cdriver: driver to be registered
 405  *
 406  * This function is mainly a wrapper around driver_register().
 407  */
 408 int ccwgroup_driver_register(struct ccwgroup_driver *cdriver)
 409 {
 410         /* register our new driver with the core */
 411         cdriver->driver.bus = &ccwgroup_bus_type;
 412         cdriver->driver.name = cdriver->name;
 413         cdriver->driver.owner = cdriver->owner;
 414
 415         return driver_register(&cdriver->driver);
 416 }
 417
 418 static int
 419 __ccwgroup_match_all(struct device *dev, void *data)
 420 {
 421         return 1;
 422 }
 423
 424 /**
 425  * ccwgroup_driver_unregister() - deregister a ccw group driver
 426  * @cdriver: driver to be deregistered
 427  *
 428  * This function is mainly a wrapper around driver_unregister().
 429  */
 430 void ccwgroup_driver_unregister(struct ccwgroup_driver *cdriver)
 431 {
 432         struct device *dev;
 433
 434         /* We don't want ccwgroup devices to live longer than their driver. */
 435         get_driver(&cdriver->driver);
 436         while ((dev = driver_find_device(&cdriver->driver, NULL, NULL,
 437                                          __ccwgroup_match_all))) {
 438                 struct ccwgroup_device *gdev = to_ccwgroupdev(dev);
 439
 440                 mutex_lock(&gdev->reg_mutex);
 441                 __ccwgroup_remove_symlinks(gdev);
 442                 device_unregister(dev);
 443                 mutex_unlock(&gdev->reg_mutex);
 444                 put_device(dev);
 445         }
 446         put_driver(&cdriver->driver);
 447         driver_unregister(&cdriver->driver);
 448 }
 449
 450 /**
 451  * ccwgroup_probe_ccwdev() - probe function for slave devices
 452  * @cdev: ccw device to be probed
 453  *
 454  * This is a dummy probe function for ccw devices that are slave devices in
 455  * a ccw group device.
 456  * Returns:
 457  *  always %0
 458  */
 459 int ccwgroup_probe_ccwdev(struct ccw_device *cdev)
 460 {
 461         return 0;
 462 }
 463
 464 static struct ccwgroup_device *
 465 __ccwgroup_get_gdev_by_cdev(struct ccw_device *cdev)
 466 {
 467         struct ccwgroup_device *gdev;
 468
 469         gdev = dev_get_drvdata(&cdev->dev);
 470         if (gdev) {
 471                 if (get_device(&gdev->dev)) {
 472                         mutex_lock(&gdev->reg_mutex);
 473                         if (device_is_registered(&gdev->dev))
 474                                 return gdev;
 475                         mutex_unlock(&gdev->reg_mutex);
 476                         put_device(&gdev->dev);
 477                 }
 478                 return NULL;
 479         }
 480         return NULL;
 481 }
 482
 483 /**
 484  * ccwgroup_remove_ccwdev() - remove function for slave devices
 485  * @cdev: ccw device to be removed
 486  *
 487  * This is a remove function for ccw devices that are slave devices in a ccw
 488  * group device. It sets the ccw device offline and also deregisters the
 489  * embedding ccw group device.
 490  */
 491 void ccwgroup_remove_ccwdev(struct ccw_device *cdev)
 492 {
 493         struct ccwgroup_device *gdev;
 494
 495         /* Ignore offlining errors, device is gone anyway. */
 496         ccw_device_set_offline(cdev);
 497         /* If one of its devices is gone, the whole group is done for. */
 498         gdev = __ccwgroup_get_gdev_by_cdev(cdev);
 499         if (gdev) {
 500                 __ccwgroup_remove_symlinks(gdev);
 501                 device_unregister(&gdev->dev);
 502                 mutex_unlock(&gdev->reg_mutex);
 503                 put_device(&gdev->dev);
 504         }
 505 }
 506
 507 MODULE_LICENSE("GPL");
 508 EXPORT_SYMBOL(ccwgroup_driver_register);
 509 EXPORT_SYMBOL(ccwgroup_driver_unregister);
 510 EXPORT_SYMBOL(ccwgroup_create);
 511 EXPORT_SYMBOL(ccwgroup_probe_ccwdev);
 512 EXPORT_SYMBOL(ccwgroup_remove_ccwdev);