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 int 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         value = simple_strtoul(buf, NULL, 0);
 333         ret = count;
 334         if (value == 1)
 335                 ccwgroup_set_online(gdev);
 336         else if (value == 0)
 337                 ccwgroup_set_offline(gdev);
 338         else
 339                 ret = -EINVAL;
 340         module_put(gdrv->owner);
 341         return ret;
 342 }
 343
 344 static ssize_t
 345 ccwgroup_online_show (struct device *dev, struct device_attribute *attr, char *buf)
 346 {
 347         int online;
 348
 349         online = (to_ccwgroupdev(dev)->state == CCWGROUP_ONLINE);
 350
 351         return sprintf(buf, online ? "1\n" : "0\n");
 352 }
 353
 354 static DEVICE_ATTR(online, 0644, ccwgroup_online_show, ccwgroup_online_store);
 355
 356 static int
 357 ccwgroup_probe (struct device *dev)
 358 {
 359         struct ccwgroup_device *gdev;
 360         struct ccwgroup_driver *gdrv;
 361
 362         int ret;
 363
 364         gdev = to_ccwgroupdev(dev);
 365         gdrv = to_ccwgroupdrv(dev->driver);
 366
 367         if ((ret = device_create_file(dev, &dev_attr_online)))
 368                 return ret;
 369
 370         ret = gdrv->probe ? gdrv->probe(gdev) : -ENODEV;
 371         if (ret)
 372                 device_remove_file(dev, &dev_attr_online);
 373
 374         return ret;
 375 }
 376
 377 static int
 378 ccwgroup_remove (struct device *dev)
 379 {
 380         struct ccwgroup_device *gdev;
 381         struct ccwgroup_driver *gdrv;
 382
 383         gdev = to_ccwgroupdev(dev);
 384         gdrv = to_ccwgroupdrv(dev->driver);
 385
 386         device_remove_file(dev, &dev_attr_online);
 387
 388         if (gdrv && gdrv->remove)
 389                 gdrv->remove(gdev);
 390         return 0;
 391 }
 392
 393 static void ccwgroup_shutdown(struct device *dev)
 394 {
 395         struct ccwgroup_device *gdev;
 396         struct ccwgroup_driver *gdrv;
 397
 398         gdev = to_ccwgroupdev(dev);
 399         gdrv = to_ccwgroupdrv(dev->driver);
 400         if (gdrv && gdrv->shutdown)
 401                 gdrv->shutdown(gdev);
 402 }
 403
 404 static struct bus_type ccwgroup_bus_type = {
 405         .name   = "ccwgroup",
 406         .match  = ccwgroup_bus_match,
 407         .uevent = ccwgroup_uevent,
 408         .probe  = ccwgroup_probe,
 409         .remove = ccwgroup_remove,
 410         .shutdown = ccwgroup_shutdown,
 411 };
 412
 413 /**
 414  * ccwgroup_driver_register() - register a ccw group driver
 415  * @cdriver: driver to be registered
 416  *
 417  * This function is mainly a wrapper around driver_register().
 418  */
 419 int ccwgroup_driver_register(struct ccwgroup_driver *cdriver)
 420 {
 421         /* register our new driver with the core */
 422         cdriver->driver.bus = &ccwgroup_bus_type;
 423         cdriver->driver.name = cdriver->name;
 424         cdriver->driver.owner = cdriver->owner;
 425
 426         return driver_register(&cdriver->driver);
 427 }
 428
 429 static int
 430 __ccwgroup_match_all(struct device *dev, void *data)
 431 {
 432         return 1;
 433 }
 434
 435 /**
 436  * ccwgroup_driver_unregister() - deregister a ccw group driver
 437  * @cdriver: driver to be deregistered
 438  *
 439  * This function is mainly a wrapper around driver_unregister().
 440  */
 441 void ccwgroup_driver_unregister(struct ccwgroup_driver *cdriver)
 442 {
 443         struct device *dev;
 444
 445         /* We don't want ccwgroup devices to live longer than their driver. */
 446         get_driver(&cdriver->driver);
 447         while ((dev = driver_find_device(&cdriver->driver, NULL, NULL,
 448                                          __ccwgroup_match_all))) {
 449                 struct ccwgroup_device *gdev = to_ccwgroupdev(dev);
 450
 451                 mutex_lock(&gdev->reg_mutex);
 452                 __ccwgroup_remove_symlinks(gdev);
 453                 device_unregister(dev);
 454                 mutex_unlock(&gdev->reg_mutex);
 455                 put_device(dev);
 456         }
 457         put_driver(&cdriver->driver);
 458         driver_unregister(&cdriver->driver);
 459 }
 460
 461 /**
 462  * ccwgroup_probe_ccwdev() - probe function for slave devices
 463  * @cdev: ccw device to be probed
 464  *
 465  * This is a dummy probe function for ccw devices that are slave devices in
 466  * a ccw group device.
 467  * Returns:
 468  *  always %0
 469  */
 470 int ccwgroup_probe_ccwdev(struct ccw_device *cdev)
 471 {
 472         return 0;
 473 }
 474
 475 static struct ccwgroup_device *
 476 __ccwgroup_get_gdev_by_cdev(struct ccw_device *cdev)
 477 {
 478         struct ccwgroup_device *gdev;
 479
 480         gdev = dev_get_drvdata(&cdev->dev);
 481         if (gdev) {
 482                 if (get_device(&gdev->dev)) {
 483                         mutex_lock(&gdev->reg_mutex);
 484                         if (device_is_registered(&gdev->dev))
 485                                 return gdev;
 486                         mutex_unlock(&gdev->reg_mutex);
 487                         put_device(&gdev->dev);
 488                 }
 489                 return NULL;
 490         }
 491         return NULL;
 492 }
 493
 494 /**
 495  * ccwgroup_remove_ccwdev() - remove function for slave devices
 496  * @cdev: ccw device to be removed
 497  *
 498  * This is a remove function for ccw devices that are slave devices in a ccw
 499  * group device. It sets the ccw device offline and also deregisters the
 500  * embedding ccw group device.
 501  */
 502 void ccwgroup_remove_ccwdev(struct ccw_device *cdev)
 503 {
 504         struct ccwgroup_device *gdev;
 505
 506         /* Ignore offlining errors, device is gone anyway. */
 507         ccw_device_set_offline(cdev);
 508         /* If one of its devices is gone, the whole group is done for. */
 509         gdev = __ccwgroup_get_gdev_by_cdev(cdev);
 510         if (gdev) {
 511                 __ccwgroup_remove_symlinks(gdev);
 512                 device_unregister(&gdev->dev);
 513                 mutex_unlock(&gdev->reg_mutex);
 514                 put_device(&gdev->dev);
 515         }
 516 }
 517
 518 MODULE_LICENSE("GPL");
 519 EXPORT_SYMBOL(ccwgroup_driver_register);
 520 EXPORT_SYMBOL(ccwgroup_driver_unregister);
 521 EXPORT_SYMBOL(ccwgroup_create);
 522 EXPORT_SYMBOL(ccwgroup_probe_ccwdev);
 523 EXPORT_SYMBOL(ccwgroup_remove_ccwdev);