err.no 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/ccwdev.h>
  20 #include <asm/ccwgroup.h>
  21
  22 /* In Linux 2.4, we had a channel device layer called "chandev"
  23  * that did all sorts of obscure stuff for networking devices.
  24  * This is another driver that serves as a replacement for just
  25  * one of its functions, namely the translation of single subchannels
  26  * to devices that use multiple subchannels.
  27  */
  28
  29 /* a device matches a driver if all its slave devices match the same
  30  * entry of the driver */
  31 static int
  32 ccwgroup_bus_match (struct device * dev, struct device_driver * drv)
  33 {
  34         struct ccwgroup_device *gdev;
  35         struct ccwgroup_driver *gdrv;
  36
  37         gdev = to_ccwgroupdev(dev);
  38         gdrv = to_ccwgroupdrv(drv);
  39
  40         if (gdev->creator_id == gdrv->driver_id)
  41                 return 1;
  42
  43         return 0;
  44 }
  45 static int
  46 ccwgroup_uevent (struct device *dev, struct kobj_uevent_env *env)
  47 {
  48         /* TODO */
  49         return 0;
  50 }
  51
  52 static struct bus_type ccwgroup_bus_type;
  53
  54 static void
  55 __ccwgroup_remove_symlinks(struct ccwgroup_device *gdev)
  56 {
  57         int i;
  58         char str[8];
  59
  60         for (i = 0; i < gdev->count; i++) {
  61                 sprintf(str, "cdev%d", i);
  62                 sysfs_remove_link(&gdev->dev.kobj, str);
  63                 sysfs_remove_link(&gdev->cdev[i]->dev.kobj, "group_device");
  64         }
  65
  66 }
  67
  68 /*
  69  * Provide an 'ungroup' attribute so the user can remove group devices no
  70  * longer needed or accidentially created. Saves memory :)
  71  */
  72 static void ccwgroup_ungroup_callback(struct device *dev)
  73 {
  74         struct ccwgroup_device *gdev = to_ccwgroupdev(dev);
  75
  76         mutex_lock(&gdev->reg_mutex);
  77         if (device_is_registered(&gdev->dev)) {
  78                 __ccwgroup_remove_symlinks(gdev);
  79                 device_unregister(dev);
  80         }
  81         mutex_unlock(&gdev->reg_mutex);
  82 }
  83
  84 static ssize_t
  85 ccwgroup_ungroup_store(struct device *dev, struct device_attribute *attr, const char *buf, size_t count)
  86 {
  87         struct ccwgroup_device *gdev;
  88         int rc;
  89
  90         gdev = to_ccwgroupdev(dev);
  91
  92         if (gdev->state != CCWGROUP_OFFLINE)
  93                 return -EINVAL;
  94
  95         /* Note that we cannot unregister the device from one of its
  96          * attribute methods, so we have to use this roundabout approach.
  97          */
  98         rc = device_schedule_callback(dev, ccwgroup_ungroup_callback);
  99         if (rc)
 100                 count = rc;
 101         return count;
 102 }
 103
 104 static DEVICE_ATTR(ungroup, 0200, NULL, ccwgroup_ungroup_store);
 105
 106 static void
 107 ccwgroup_release (struct device *dev)
 108 {
 109         struct ccwgroup_device *gdev;
 110         int i;
 111
 112         gdev = to_ccwgroupdev(dev);
 113
 114         for (i = 0; i < gdev->count; i++) {
 115                 dev_set_drvdata(&gdev->cdev[i]->dev, NULL);
 116                 put_device(&gdev->cdev[i]->dev);
 117         }
 118         kfree(gdev);
 119 }
 120
 121 static int
 122 __ccwgroup_create_symlinks(struct ccwgroup_device *gdev)
 123 {
 124         char str[8];
 125         int i, rc;
 126
 127         for (i = 0; i < gdev->count; i++) {
 128                 rc = sysfs_create_link(&gdev->cdev[i]->dev.kobj, &gdev->dev.kobj,
 129                                        "group_device");
 130                 if (rc) {
 131                         for (--i; i >= 0; i--)
 132                                 sysfs_remove_link(&gdev->cdev[i]->dev.kobj,
 133                                                   "group_device");
 134                         return rc;
 135                 }
 136         }
 137         for (i = 0; i < gdev->count; i++) {
 138                 sprintf(str, "cdev%d", i);
 139                 rc = sysfs_create_link(&gdev->dev.kobj, &gdev->cdev[i]->dev.kobj,
 140                                        str);
 141                 if (rc) {
 142                         for (--i; i >= 0; i--) {
 143                                 sprintf(str, "cdev%d", i);
 144                                 sysfs_remove_link(&gdev->dev.kobj, str);
 145                         }
 146                         for (i = 0; i < gdev->count; i++)
 147                                 sysfs_remove_link(&gdev->cdev[i]->dev.kobj,
 148                                                   "group_device");
 149                         return rc;
 150                 }
 151         }
 152         return 0;
 153 }
 154
 155 /**
 156  * ccwgroup_create() - create and register a ccw group device
 157  * @root: parent device for the new device
 158  * @creator_id: identifier of creating driver
 159  * @cdrv: ccw driver of slave devices
 160  * @argc: number of slave devices
 161  * @argv: bus ids of slave devices
 162  *
 163  * Create and register a new ccw group device as a child of @root. Slave
 164  * devices are obtained from the list of bus ids given in @argv[] and must all
 165  * belong to @cdrv.
 166  * Returns:
 167  *  %0 on success and an error code on failure.
 168  * Context:
 169  *  non-atomic
 170  */
 171 int ccwgroup_create(struct device *root, unsigned int creator_id,
 172                     struct ccw_driver *cdrv, int argc, char *argv[])
 173 {
 174         struct ccwgroup_device *gdev;
 175         int i;
 176         int rc;
 177
 178         if (argc > 256) /* disallow dumb users */
 179                 return -EINVAL;
 180
 181         gdev = kzalloc(sizeof(*gdev) + argc*sizeof(gdev->cdev[0]), GFP_KERNEL);
 182         if (!gdev)
 183                 return -ENOMEM;
 184
 185         atomic_set(&gdev->onoff, 0);
 186         mutex_init(&gdev->reg_mutex);
 187         mutex_lock(&gdev->reg_mutex);
 188         for (i = 0; i < argc; i++) {
 189                 gdev->cdev[i] = get_ccwdev_by_busid(cdrv, argv[i]);
 190
 191                 /* all devices have to be of the same type in
 192                  * order to be grouped */
 193                 if (!gdev->cdev[i]
 194                     || gdev->cdev[i]->id.driver_info !=
 195                     gdev->cdev[0]->id.driver_info) {
 196                         rc = -EINVAL;
 197                         goto error;
 198                 }
 199                 /* Don't allow a device to belong to more than one group. */
 200                 if (dev_get_drvdata(&gdev->cdev[i]->dev)) {
 201                         rc = -EINVAL;
 202                         goto error;
 203                 }
 204                 dev_set_drvdata(&gdev->cdev[i]->dev, gdev);
 205         }
 206
 207         gdev->creator_id = creator_id;
 208         gdev->count = argc;
 209         gdev->dev.bus = &ccwgroup_bus_type;
 210         gdev->dev.parent = root;
 211         gdev->dev.release = ccwgroup_release;
 212
 213         snprintf (gdev->dev.bus_id, BUS_ID_SIZE, "%s",
 214                         gdev->cdev[0]->dev.bus_id);
 215
 216         rc = device_register(&gdev->dev);
 217         if (rc)
 218                 goto error;
 219         get_device(&gdev->dev);
 220         rc = device_create_file(&gdev->dev, &dev_attr_ungroup);
 221
 222         if (rc) {
 223                 device_unregister(&gdev->dev);
 224                 goto error;
 225         }
 226
 227         rc = __ccwgroup_create_symlinks(gdev);
 228         if (!rc) {
 229                 mutex_unlock(&gdev->reg_mutex);
 230                 put_device(&gdev->dev);
 231                 return 0;
 232         }
 233         device_remove_file(&gdev->dev, &dev_attr_ungroup);
 234         device_unregister(&gdev->dev);
 235 error:
 236         for (i = 0; i < argc; i++)
 237                 if (gdev->cdev[i]) {
 238                         if (dev_get_drvdata(&gdev->cdev[i]->dev) == gdev)
 239                                 dev_set_drvdata(&gdev->cdev[i]->dev, NULL);
 240                         put_device(&gdev->cdev[i]->dev);
 241                 }
 242         mutex_unlock(&gdev->reg_mutex);
 243         put_device(&gdev->dev);
 244         return rc;
 245 }
 246
 247 static int __init
 248 init_ccwgroup (void)
 249 {
 250         return bus_register (&ccwgroup_bus_type);
 251 }
 252
 253 static void __exit
 254 cleanup_ccwgroup (void)
 255 {
 256         bus_unregister (&ccwgroup_bus_type);
 257 }
 258
 259 module_init(init_ccwgroup);
 260 module_exit(cleanup_ccwgroup);
 261
 262 /************************** driver stuff ******************************/
 263
 264 static int
 265 ccwgroup_set_online(struct ccwgroup_device *gdev)
 266 {
 267         struct ccwgroup_driver *gdrv;
 268         int ret;
 269
 270         if (atomic_cmpxchg(&gdev->onoff, 0, 1) != 0)
 271                 return -EAGAIN;
 272         if (gdev->state == CCWGROUP_ONLINE) {
 273                 ret = 0;
 274                 goto out;
 275         }
 276         if (!gdev->dev.driver) {
 277                 ret = -EINVAL;
 278                 goto out;
 279         }
 280         gdrv = to_ccwgroupdrv (gdev->dev.driver);
 281         if ((ret = gdrv->set_online ? gdrv->set_online(gdev) : 0))
 282                 goto out;
 283
 284         gdev->state = CCWGROUP_ONLINE;
 285  out:
 286         atomic_set(&gdev->onoff, 0);
 287         return ret;
 288 }
 289
 290 static int
 291 ccwgroup_set_offline(struct ccwgroup_device *gdev)
 292 {
 293         struct ccwgroup_driver *gdrv;
 294         int ret;
 295
 296         if (atomic_cmpxchg(&gdev->onoff, 0, 1) != 0)
 297                 return -EAGAIN;
 298         if (gdev->state == CCWGROUP_OFFLINE) {
 299                 ret = 0;
 300                 goto out;
 301         }
 302         if (!gdev->dev.driver) {
 303                 ret = -EINVAL;
 304                 goto out;
 305         }
 306         gdrv = to_ccwgroupdrv (gdev->dev.driver);
 307         if ((ret = gdrv->set_offline ? gdrv->set_offline(gdev) : 0))
 308                 goto out;
 309
 310         gdev->state = CCWGROUP_OFFLINE;
 311  out:
 312         atomic_set(&gdev->onoff, 0);
 313         return ret;
 314 }
 315
 316 static ssize_t
 317 ccwgroup_online_store (struct device *dev, struct device_attribute *attr, const char *buf, size_t count)
 318 {
 319         struct ccwgroup_device *gdev;
 320         struct ccwgroup_driver *gdrv;
 321         unsigned long value;
 322         int ret;
 323
 324         gdev = to_ccwgroupdev(dev);
 325         if (!dev->driver)
 326                 return count;
 327
 328         gdrv = to_ccwgroupdrv (gdev->dev.driver);
 329         if (!try_module_get(gdrv->owner))
 330                 return -EINVAL;
 331
 332         ret = strict_strtoul(buf, 0, &value);
 333         if (ret)
 334                 goto out;
 335         ret = count;
 336         if (value == 1)
 337                 ccwgroup_set_online(gdev);
 338         else if (value == 0)
 339                 ccwgroup_set_offline(gdev);
 340         else
 341                 ret = -EINVAL;
 342 out:
 343         module_put(gdrv->owner);
 344         return ret;
 345 }
 346
 347 static ssize_t
 348 ccwgroup_online_show (struct device *dev, struct device_attribute *attr, char *buf)
 349 {
 350         int online;
 351
 352         online = (to_ccwgroupdev(dev)->state == CCWGROUP_ONLINE);
 353
 354         return sprintf(buf, online ? "1\n" : "0\n");
 355 }
 356
 357 static DEVICE_ATTR(online, 0644, ccwgroup_online_show, ccwgroup_online_store);
 358
 359 static int
 360 ccwgroup_probe (struct device *dev)
 361 {
 362         struct ccwgroup_device *gdev;
 363         struct ccwgroup_driver *gdrv;
 364
 365         int ret;
 366
 367         gdev = to_ccwgroupdev(dev);
 368         gdrv = to_ccwgroupdrv(dev->driver);
 369
 370         if ((ret = device_create_file(dev, &dev_attr_online)))
 371                 return ret;
 372
 373         ret = gdrv->probe ? gdrv->probe(gdev) : -ENODEV;
 374         if (ret)
 375                 device_remove_file(dev, &dev_attr_online);
 376
 377         return ret;
 378 }
 379
 380 static int
 381 ccwgroup_remove (struct device *dev)
 382 {
 383         struct ccwgroup_device *gdev;
 384         struct ccwgroup_driver *gdrv;
 385
 386         gdev = to_ccwgroupdev(dev);
 387         gdrv = to_ccwgroupdrv(dev->driver);
 388
 389         device_remove_file(dev, &dev_attr_online);
 390
 391         if (gdrv && gdrv->remove)
 392                 gdrv->remove(gdev);
 393         return 0;
 394 }
 395
 396 static void ccwgroup_shutdown(struct device *dev)
 397 {
 398         struct ccwgroup_device *gdev;
 399         struct ccwgroup_driver *gdrv;
 400
 401         gdev = to_ccwgroupdev(dev);
 402         gdrv = to_ccwgroupdrv(dev->driver);
 403         if (gdrv && gdrv->shutdown)
 404                 gdrv->shutdown(gdev);
 405 }
 406
 407 static struct bus_type ccwgroup_bus_type = {
 408         .name   = "ccwgroup",
 409         .match  = ccwgroup_bus_match,
 410         .uevent = ccwgroup_uevent,
 411         .probe  = ccwgroup_probe,
 412         .remove = ccwgroup_remove,
 413         .shutdown = ccwgroup_shutdown,
 414 };
 415
 416 /**
 417  * ccwgroup_driver_register() - register a ccw group driver
 418  * @cdriver: driver to be registered
 419  *
 420  * This function is mainly a wrapper around driver_register().
 421  */
 422 int ccwgroup_driver_register(struct ccwgroup_driver *cdriver)
 423 {
 424         /* register our new driver with the core */
 425         cdriver->driver.bus = &ccwgroup_bus_type;
 426         cdriver->driver.name = cdriver->name;
 427         cdriver->driver.owner = cdriver->owner;
 428
 429         return driver_register(&cdriver->driver);
 430 }
 431
 432 static int
 433 __ccwgroup_match_all(struct device *dev, void *data)
 434 {
 435         return 1;
 436 }
 437
 438 /**
 439  * ccwgroup_driver_unregister() - deregister a ccw group driver
 440  * @cdriver: driver to be deregistered
 441  *
 442  * This function is mainly a wrapper around driver_unregister().
 443  */
 444 void ccwgroup_driver_unregister(struct ccwgroup_driver *cdriver)
 445 {
 446         struct device *dev;
 447
 448         /* We don't want ccwgroup devices to live longer than their driver. */
 449         get_driver(&cdriver->driver);
 450         while ((dev = driver_find_device(&cdriver->driver, NULL, NULL,
 451                                          __ccwgroup_match_all))) {
 452                 struct ccwgroup_device *gdev = to_ccwgroupdev(dev);
 453
 454                 mutex_lock(&gdev->reg_mutex);
 455                 __ccwgroup_remove_symlinks(gdev);
 456                 device_unregister(dev);
 457                 mutex_unlock(&gdev->reg_mutex);
 458                 put_device(dev);
 459         }
 460         put_driver(&cdriver->driver);
 461         driver_unregister(&cdriver->driver);
 462 }
 463
 464 /**
 465  * ccwgroup_probe_ccwdev() - probe function for slave devices
 466  * @cdev: ccw device to be probed
 467  *
 468  * This is a dummy probe function for ccw devices that are slave devices in
 469  * a ccw group device.
 470  * Returns:
 471  *  always %0
 472  */
 473 int ccwgroup_probe_ccwdev(struct ccw_device *cdev)
 474 {
 475         return 0;
 476 }
 477
 478 static struct ccwgroup_device *
 479 __ccwgroup_get_gdev_by_cdev(struct ccw_device *cdev)
 480 {
 481         struct ccwgroup_device *gdev;
 482
 483         gdev = dev_get_drvdata(&cdev->dev);
 484         if (gdev) {
 485                 if (get_device(&gdev->dev)) {
 486                         mutex_lock(&gdev->reg_mutex);
 487                         if (device_is_registered(&gdev->dev))
 488                                 return gdev;
 489                         mutex_unlock(&gdev->reg_mutex);
 490                         put_device(&gdev->dev);
 491                 }
 492                 return NULL;
 493         }
 494         return NULL;
 495 }
 496
 497 /**
 498  * ccwgroup_remove_ccwdev() - remove function for slave devices
 499  * @cdev: ccw device to be removed
 500  *
 501  * This is a remove function for ccw devices that are slave devices in a ccw
 502  * group device. It sets the ccw device offline and also deregisters the
 503  * embedding ccw group device.
 504  */
 505 void ccwgroup_remove_ccwdev(struct ccw_device *cdev)
 506 {
 507         struct ccwgroup_device *gdev;
 508
 509         /* Ignore offlining errors, device is gone anyway. */
 510         ccw_device_set_offline(cdev);
 511         /* If one of its devices is gone, the whole group is done for. */
 512         gdev = __ccwgroup_get_gdev_by_cdev(cdev);
 513         if (gdev) {
 514                 __ccwgroup_remove_symlinks(gdev);
 515                 device_unregister(&gdev->dev);
 516                 mutex_unlock(&gdev->reg_mutex);
 517                 put_device(&gdev->dev);
 518         }
 519 }
 520
 521 MODULE_LICENSE("GPL");
 522 EXPORT_SYMBOL(ccwgroup_driver_register);
 523 EXPORT_SYMBOL(ccwgroup_driver_unregister);
 524 EXPORT_SYMBOL(ccwgroup_create);
 525 EXPORT_SYMBOL(ccwgroup_probe_ccwdev);
 526 EXPORT_SYMBOL(ccwgroup_remove_ccwdev);