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                 if (gdev->cdev[i]) {
 116                         if (dev_get_drvdata(&gdev->cdev[i]->dev) == gdev)
 117                                 dev_set_drvdata(&gdev->cdev[i]->dev, NULL);
 118                         put_device(&gdev->cdev[i]->dev);
 119                 }
 120         }
 121         kfree(gdev);
 122 }
 123
 124 static int
 125 __ccwgroup_create_symlinks(struct ccwgroup_device *gdev)
 126 {
 127         char str[8];
 128         int i, rc;
 129
 130         for (i = 0; i < gdev->count; i++) {
 131                 rc = sysfs_create_link(&gdev->cdev[i]->dev.kobj, &gdev->dev.kobj,
 132                                        "group_device");
 133                 if (rc) {
 134                         for (--i; i >= 0; i--)
 135                                 sysfs_remove_link(&gdev->cdev[i]->dev.kobj,
 136                                                   "group_device");
 137                         return rc;
 138                 }
 139         }
 140         for (i = 0; i < gdev->count; i++) {
 141                 sprintf(str, "cdev%d", i);
 142                 rc = sysfs_create_link(&gdev->dev.kobj, &gdev->cdev[i]->dev.kobj,
 143                                        str);
 144                 if (rc) {
 145                         for (--i; i >= 0; i--) {
 146                                 sprintf(str, "cdev%d", i);
 147                                 sysfs_remove_link(&gdev->dev.kobj, str);
 148                         }
 149                         for (i = 0; i < gdev->count; i++)
 150                                 sysfs_remove_link(&gdev->cdev[i]->dev.kobj,
 151                                                   "group_device");
 152                         return rc;
 153                 }
 154         }
 155         return 0;
 156 }
 157
 158 static int __get_next_bus_id(const char **buf, char *bus_id)
 159 {
 160         int rc, len;
 161         char *start, *end;
 162
 163         start = (char *)*buf;
 164         end = strchr(start, ',');
 165         if (!end) {
 166                 /* Last entry. Strip trailing newline, if applicable. */
 167                 end = strchr(start, '\n');
 168                 if (end)
 169                         *end = '\0';
 170                 len = strlen(start) + 1;
 171         } else {
 172                 len = end - start + 1;
 173                 end++;
 174         }
 175         if (len < BUS_ID_SIZE) {
 176                 strlcpy(bus_id, start, len);
 177                 rc = 0;
 178         } else
 179                 rc = -EINVAL;
 180         *buf = end;
 181         return rc;
 182 }
 183
 184 static int __is_valid_bus_id(char bus_id[BUS_ID_SIZE])
 185 {
 186         int cssid, ssid, devno;
 187
 188         /* Must be of form %x.%x.%04x */
 189         if (sscanf(bus_id, "%x.%1x.%04x", &cssid, &ssid, &devno) != 3)
 190                 return 0;
 191         return 1;
 192 }
 193
 194 /**
 195  * ccwgroup_create_from_string() - create and register a ccw group device
 196  * @root: parent device for the new device
 197  * @creator_id: identifier of creating driver
 198  * @cdrv: ccw driver of slave devices
 199  * @num_devices: number of slave devices
 200  * @buf: buffer containing comma separated bus ids of slave devices
 201  *
 202  * Create and register a new ccw group device as a child of @root. Slave
 203  * devices are obtained from the list of bus ids given in @buf and must all
 204  * belong to @cdrv.
 205  * Returns:
 206  *  %0 on success and an error code on failure.
 207  * Context:
 208  *  non-atomic
 209  */
 210 int ccwgroup_create_from_string(struct device *root, unsigned int creator_id,
 211                                 struct ccw_driver *cdrv, int num_devices,
 212                                 const char *buf)
 213 {
 214         struct ccwgroup_device *gdev;
 215         int rc, i;
 216         char tmp_bus_id[BUS_ID_SIZE];
 217         const char *curr_buf;
 218
 219         gdev = kzalloc(sizeof(*gdev) + num_devices * sizeof(gdev->cdev[0]),
 220                        GFP_KERNEL);
 221         if (!gdev)
 222                 return -ENOMEM;
 223
 224         atomic_set(&gdev->onoff, 0);
 225         mutex_init(&gdev->reg_mutex);
 226         mutex_lock(&gdev->reg_mutex);
 227         gdev->creator_id = creator_id;
 228         gdev->count = num_devices;
 229         gdev->dev.bus = &ccwgroup_bus_type;
 230         gdev->dev.parent = root;
 231         gdev->dev.release = ccwgroup_release;
 232         device_initialize(&gdev->dev);
 233
 234         curr_buf = buf;
 235         for (i = 0; i < num_devices && curr_buf; i++) {
 236                 rc = __get_next_bus_id(&curr_buf, tmp_bus_id);
 237                 if (rc != 0)
 238                         goto error;
 239                 if (!__is_valid_bus_id(tmp_bus_id)) {
 240                         rc = -EINVAL;
 241                         goto error;
 242                 }
 243                 gdev->cdev[i] = get_ccwdev_by_busid(cdrv, tmp_bus_id);
 244                 /*
 245                  * All devices have to be of the same type in
 246                  * order to be grouped.
 247                  */
 248                 if (!gdev->cdev[i]
 249                     || gdev->cdev[i]->id.driver_info !=
 250                     gdev->cdev[0]->id.driver_info) {
 251                         rc = -EINVAL;
 252                         goto error;
 253                 }
 254                 /* Don't allow a device to belong to more than one group. */
 255                 if (dev_get_drvdata(&gdev->cdev[i]->dev)) {
 256                         rc = -EINVAL;
 257                         goto error;
 258                 }
 259                 dev_set_drvdata(&gdev->cdev[i]->dev, gdev);
 260         }
 261         /* Check for sufficient number of bus ids. */
 262         if (i < num_devices && !curr_buf) {
 263                 rc = -EINVAL;
 264                 goto error;
 265         }
 266         /* Check for trailing stuff. */
 267         if (i == num_devices && strlen(curr_buf) > 0) {
 268                 rc = -EINVAL;
 269                 goto error;
 270         }
 271
 272         snprintf (gdev->dev.bus_id, BUS_ID_SIZE, "%s",
 273                         gdev->cdev[0]->dev.bus_id);
 274
 275         rc = device_add(&gdev->dev);
 276         if (rc)
 277                 goto error;
 278         get_device(&gdev->dev);
 279         rc = device_create_file(&gdev->dev, &dev_attr_ungroup);
 280
 281         if (rc) {
 282                 device_unregister(&gdev->dev);
 283                 goto error;
 284         }
 285
 286         rc = __ccwgroup_create_symlinks(gdev);
 287         if (!rc) {
 288                 mutex_unlock(&gdev->reg_mutex);
 289                 put_device(&gdev->dev);
 290                 return 0;
 291         }
 292         device_remove_file(&gdev->dev, &dev_attr_ungroup);
 293         device_unregister(&gdev->dev);
 294 error:
 295         for (i = 0; i < num_devices; i++)
 296                 if (gdev->cdev[i]) {
 297                         if (dev_get_drvdata(&gdev->cdev[i]->dev) == gdev)
 298                                 dev_set_drvdata(&gdev->cdev[i]->dev, NULL);
 299                         put_device(&gdev->cdev[i]->dev);
 300                         gdev->cdev[i] = NULL;
 301                 }
 302         mutex_unlock(&gdev->reg_mutex);
 303         put_device(&gdev->dev);
 304         return rc;
 305 }
 306 EXPORT_SYMBOL(ccwgroup_create_from_string);
 307
 308 static int __init
 309 init_ccwgroup (void)
 310 {
 311         return bus_register (&ccwgroup_bus_type);
 312 }
 313
 314 static void __exit
 315 cleanup_ccwgroup (void)
 316 {
 317         bus_unregister (&ccwgroup_bus_type);
 318 }
 319
 320 module_init(init_ccwgroup);
 321 module_exit(cleanup_ccwgroup);
 322
 323 /************************** driver stuff ******************************/
 324
 325 static int
 326 ccwgroup_set_online(struct ccwgroup_device *gdev)
 327 {
 328         struct ccwgroup_driver *gdrv;
 329         int ret;
 330
 331         if (atomic_cmpxchg(&gdev->onoff, 0, 1) != 0)
 332                 return -EAGAIN;
 333         if (gdev->state == CCWGROUP_ONLINE) {
 334                 ret = 0;
 335                 goto out;
 336         }
 337         if (!gdev->dev.driver) {
 338                 ret = -EINVAL;
 339                 goto out;
 340         }
 341         gdrv = to_ccwgroupdrv (gdev->dev.driver);
 342         if ((ret = gdrv->set_online ? gdrv->set_online(gdev) : 0))
 343                 goto out;
 344
 345         gdev->state = CCWGROUP_ONLINE;
 346  out:
 347         atomic_set(&gdev->onoff, 0);
 348         return ret;
 349 }
 350
 351 static int
 352 ccwgroup_set_offline(struct ccwgroup_device *gdev)
 353 {
 354         struct ccwgroup_driver *gdrv;
 355         int ret;
 356
 357         if (atomic_cmpxchg(&gdev->onoff, 0, 1) != 0)
 358                 return -EAGAIN;
 359         if (gdev->state == CCWGROUP_OFFLINE) {
 360                 ret = 0;
 361                 goto out;
 362         }
 363         if (!gdev->dev.driver) {
 364                 ret = -EINVAL;
 365                 goto out;
 366         }
 367         gdrv = to_ccwgroupdrv (gdev->dev.driver);
 368         if ((ret = gdrv->set_offline ? gdrv->set_offline(gdev) : 0))
 369                 goto out;
 370
 371         gdev->state = CCWGROUP_OFFLINE;
 372  out:
 373         atomic_set(&gdev->onoff, 0);
 374         return ret;
 375 }
 376
 377 static ssize_t
 378 ccwgroup_online_store (struct device *dev, struct device_attribute *attr, const char *buf, size_t count)
 379 {
 380         struct ccwgroup_device *gdev;
 381         struct ccwgroup_driver *gdrv;
 382         unsigned long value;
 383         int ret;
 384
 385         gdev = to_ccwgroupdev(dev);
 386         if (!dev->driver)
 387                 return count;
 388
 389         gdrv = to_ccwgroupdrv (gdev->dev.driver);
 390         if (!try_module_get(gdrv->owner))
 391                 return -EINVAL;
 392
 393         ret = strict_strtoul(buf, 0, &value);
 394         if (ret)
 395                 goto out;
 396         ret = count;
 397         if (value == 1)
 398                 ccwgroup_set_online(gdev);
 399         else if (value == 0)
 400                 ccwgroup_set_offline(gdev);
 401         else
 402                 ret = -EINVAL;
 403 out:
 404         module_put(gdrv->owner);
 405         return ret;
 406 }
 407
 408 static ssize_t
 409 ccwgroup_online_show (struct device *dev, struct device_attribute *attr, char *buf)
 410 {
 411         int online;
 412
 413         online = (to_ccwgroupdev(dev)->state == CCWGROUP_ONLINE);
 414
 415         return sprintf(buf, online ? "1\n" : "0\n");
 416 }
 417
 418 static DEVICE_ATTR(online, 0644, ccwgroup_online_show, ccwgroup_online_store);
 419
 420 static int
 421 ccwgroup_probe (struct device *dev)
 422 {
 423         struct ccwgroup_device *gdev;
 424         struct ccwgroup_driver *gdrv;
 425
 426         int ret;
 427
 428         gdev = to_ccwgroupdev(dev);
 429         gdrv = to_ccwgroupdrv(dev->driver);
 430
 431         if ((ret = device_create_file(dev, &dev_attr_online)))
 432                 return ret;
 433
 434         ret = gdrv->probe ? gdrv->probe(gdev) : -ENODEV;
 435         if (ret)
 436                 device_remove_file(dev, &dev_attr_online);
 437
 438         return ret;
 439 }
 440
 441 static int
 442 ccwgroup_remove (struct device *dev)
 443 {
 444         struct ccwgroup_device *gdev;
 445         struct ccwgroup_driver *gdrv;
 446
 447         gdev = to_ccwgroupdev(dev);
 448         gdrv = to_ccwgroupdrv(dev->driver);
 449
 450         device_remove_file(dev, &dev_attr_online);
 451
 452         if (gdrv && gdrv->remove)
 453                 gdrv->remove(gdev);
 454         return 0;
 455 }
 456
 457 static void ccwgroup_shutdown(struct device *dev)
 458 {
 459         struct ccwgroup_device *gdev;
 460         struct ccwgroup_driver *gdrv;
 461
 462         gdev = to_ccwgroupdev(dev);
 463         gdrv = to_ccwgroupdrv(dev->driver);
 464         if (gdrv && gdrv->shutdown)
 465                 gdrv->shutdown(gdev);
 466 }
 467
 468 static struct bus_type ccwgroup_bus_type = {
 469         .name   = "ccwgroup",
 470         .match  = ccwgroup_bus_match,
 471         .uevent = ccwgroup_uevent,
 472         .probe  = ccwgroup_probe,
 473         .remove = ccwgroup_remove,
 474         .shutdown = ccwgroup_shutdown,
 475 };
 476
 477 /**
 478  * ccwgroup_driver_register() - register a ccw group driver
 479  * @cdriver: driver to be registered
 480  *
 481  * This function is mainly a wrapper around driver_register().
 482  */
 483 int ccwgroup_driver_register(struct ccwgroup_driver *cdriver)
 484 {
 485         /* register our new driver with the core */
 486         cdriver->driver.bus = &ccwgroup_bus_type;
 487         cdriver->driver.name = cdriver->name;
 488         cdriver->driver.owner = cdriver->owner;
 489
 490         return driver_register(&cdriver->driver);
 491 }
 492
 493 static int
 494 __ccwgroup_match_all(struct device *dev, void *data)
 495 {
 496         return 1;
 497 }
 498
 499 /**
 500  * ccwgroup_driver_unregister() - deregister a ccw group driver
 501  * @cdriver: driver to be deregistered
 502  *
 503  * This function is mainly a wrapper around driver_unregister().
 504  */
 505 void ccwgroup_driver_unregister(struct ccwgroup_driver *cdriver)
 506 {
 507         struct device *dev;
 508
 509         /* We don't want ccwgroup devices to live longer than their driver. */
 510         get_driver(&cdriver->driver);
 511         while ((dev = driver_find_device(&cdriver->driver, NULL, NULL,
 512                                          __ccwgroup_match_all))) {
 513                 struct ccwgroup_device *gdev = to_ccwgroupdev(dev);
 514
 515                 mutex_lock(&gdev->reg_mutex);
 516                 __ccwgroup_remove_symlinks(gdev);
 517                 device_unregister(dev);
 518                 mutex_unlock(&gdev->reg_mutex);
 519                 put_device(dev);
 520         }
 521         put_driver(&cdriver->driver);
 522         driver_unregister(&cdriver->driver);
 523 }
 524
 525 /**
 526  * ccwgroup_probe_ccwdev() - probe function for slave devices
 527  * @cdev: ccw device to be probed
 528  *
 529  * This is a dummy probe function for ccw devices that are slave devices in
 530  * a ccw group device.
 531  * Returns:
 532  *  always %0
 533  */
 534 int ccwgroup_probe_ccwdev(struct ccw_device *cdev)
 535 {
 536         return 0;
 537 }
 538
 539 static struct ccwgroup_device *
 540 __ccwgroup_get_gdev_by_cdev(struct ccw_device *cdev)
 541 {
 542         struct ccwgroup_device *gdev;
 543
 544         gdev = dev_get_drvdata(&cdev->dev);
 545         if (gdev) {
 546                 if (get_device(&gdev->dev)) {
 547                         mutex_lock(&gdev->reg_mutex);
 548                         if (device_is_registered(&gdev->dev))
 549                                 return gdev;
 550                         mutex_unlock(&gdev->reg_mutex);
 551                         put_device(&gdev->dev);
 552                 }
 553                 return NULL;
 554         }
 555         return NULL;
 556 }
 557
 558 /**
 559  * ccwgroup_remove_ccwdev() - remove function for slave devices
 560  * @cdev: ccw device to be removed
 561  *
 562  * This is a remove function for ccw devices that are slave devices in a ccw
 563  * group device. It sets the ccw device offline and also deregisters the
 564  * embedding ccw group device.
 565  */
 566 void ccwgroup_remove_ccwdev(struct ccw_device *cdev)
 567 {
 568         struct ccwgroup_device *gdev;
 569
 570         /* Ignore offlining errors, device is gone anyway. */
 571         ccw_device_set_offline(cdev);
 572         /* If one of its devices is gone, the whole group is done for. */
 573         gdev = __ccwgroup_get_gdev_by_cdev(cdev);
 574         if (gdev) {
 575                 __ccwgroup_remove_symlinks(gdev);
 576                 device_unregister(&gdev->dev);
 577                 mutex_unlock(&gdev->reg_mutex);
 578                 put_device(&gdev->dev);
 579         }
 580 }
 581
 582 MODULE_LICENSE("GPL");
 583 EXPORT_SYMBOL(ccwgroup_driver_register);
 584 EXPORT_SYMBOL(ccwgroup_driver_unregister);
 585 EXPORT_SYMBOL(ccwgroup_probe_ccwdev);
 586 EXPORT_SYMBOL(ccwgroup_remove_ccwdev);