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         dev_set_name(&gdev->dev, "%s", dev_name(&gdev->cdev[0]->dev));
 273
 274         rc = device_add(&gdev->dev);
 275         if (rc)
 276                 goto error;
 277         get_device(&gdev->dev);
 278         rc = device_create_file(&gdev->dev, &dev_attr_ungroup);
 279
 280         if (rc) {
 281                 device_unregister(&gdev->dev);
 282                 goto error;
 283         }
 284
 285         rc = __ccwgroup_create_symlinks(gdev);
 286         if (!rc) {
 287                 mutex_unlock(&gdev->reg_mutex);
 288                 put_device(&gdev->dev);
 289                 return 0;
 290         }
 291         device_remove_file(&gdev->dev, &dev_attr_ungroup);
 292         device_unregister(&gdev->dev);
 293 error:
 294         for (i = 0; i < num_devices; i++)
 295                 if (gdev->cdev[i]) {
 296                         if (dev_get_drvdata(&gdev->cdev[i]->dev) == gdev)
 297                                 dev_set_drvdata(&gdev->cdev[i]->dev, NULL);
 298                         put_device(&gdev->cdev[i]->dev);
 299                         gdev->cdev[i] = NULL;
 300                 }
 301         mutex_unlock(&gdev->reg_mutex);
 302         put_device(&gdev->dev);
 303         return rc;
 304 }
 305 EXPORT_SYMBOL(ccwgroup_create_from_string);
 306
 307 static int __init
 308 init_ccwgroup (void)
 309 {
 310         return bus_register (&ccwgroup_bus_type);
 311 }
 312
 313 static void __exit
 314 cleanup_ccwgroup (void)
 315 {
 316         bus_unregister (&ccwgroup_bus_type);
 317 }
 318
 319 module_init(init_ccwgroup);
 320 module_exit(cleanup_ccwgroup);
 321
 322 /************************** driver stuff ******************************/
 323
 324 static int
 325 ccwgroup_set_online(struct ccwgroup_device *gdev)
 326 {
 327         struct ccwgroup_driver *gdrv;
 328         int ret;
 329
 330         if (atomic_cmpxchg(&gdev->onoff, 0, 1) != 0)
 331                 return -EAGAIN;
 332         if (gdev->state == CCWGROUP_ONLINE) {
 333                 ret = 0;
 334                 goto out;
 335         }
 336         if (!gdev->dev.driver) {
 337                 ret = -EINVAL;
 338                 goto out;
 339         }
 340         gdrv = to_ccwgroupdrv (gdev->dev.driver);
 341         if ((ret = gdrv->set_online ? gdrv->set_online(gdev) : 0))
 342                 goto out;
 343
 344         gdev->state = CCWGROUP_ONLINE;
 345  out:
 346         atomic_set(&gdev->onoff, 0);
 347         return ret;
 348 }
 349
 350 static int
 351 ccwgroup_set_offline(struct ccwgroup_device *gdev)
 352 {
 353         struct ccwgroup_driver *gdrv;
 354         int ret;
 355
 356         if (atomic_cmpxchg(&gdev->onoff, 0, 1) != 0)
 357                 return -EAGAIN;
 358         if (gdev->state == CCWGROUP_OFFLINE) {
 359                 ret = 0;
 360                 goto out;
 361         }
 362         if (!gdev->dev.driver) {
 363                 ret = -EINVAL;
 364                 goto out;
 365         }
 366         gdrv = to_ccwgroupdrv (gdev->dev.driver);
 367         if ((ret = gdrv->set_offline ? gdrv->set_offline(gdev) : 0))
 368                 goto out;
 369
 370         gdev->state = CCWGROUP_OFFLINE;
 371  out:
 372         atomic_set(&gdev->onoff, 0);
 373         return ret;
 374 }
 375
 376 static ssize_t
 377 ccwgroup_online_store (struct device *dev, struct device_attribute *attr, const char *buf, size_t count)
 378 {
 379         struct ccwgroup_device *gdev;
 380         struct ccwgroup_driver *gdrv;
 381         unsigned long value;
 382         int ret;
 383
 384         gdev = to_ccwgroupdev(dev);
 385         if (!dev->driver)
 386                 return count;
 387
 388         gdrv = to_ccwgroupdrv (gdev->dev.driver);
 389         if (!try_module_get(gdrv->owner))
 390                 return -EINVAL;
 391
 392         ret = strict_strtoul(buf, 0, &value);
 393         if (ret)
 394                 goto out;
 395         ret = count;
 396         if (value == 1)
 397                 ccwgroup_set_online(gdev);
 398         else if (value == 0)
 399                 ccwgroup_set_offline(gdev);
 400         else
 401                 ret = -EINVAL;
 402 out:
 403         module_put(gdrv->owner);
 404         return ret;
 405 }
 406
 407 static ssize_t
 408 ccwgroup_online_show (struct device *dev, struct device_attribute *attr, char *buf)
 409 {
 410         int online;
 411
 412         online = (to_ccwgroupdev(dev)->state == CCWGROUP_ONLINE);
 413
 414         return sprintf(buf, online ? "1\n" : "0\n");
 415 }
 416
 417 static DEVICE_ATTR(online, 0644, ccwgroup_online_show, ccwgroup_online_store);
 418
 419 static int
 420 ccwgroup_probe (struct device *dev)
 421 {
 422         struct ccwgroup_device *gdev;
 423         struct ccwgroup_driver *gdrv;
 424
 425         int ret;
 426
 427         gdev = to_ccwgroupdev(dev);
 428         gdrv = to_ccwgroupdrv(dev->driver);
 429
 430         if ((ret = device_create_file(dev, &dev_attr_online)))
 431                 return ret;
 432
 433         ret = gdrv->probe ? gdrv->probe(gdev) : -ENODEV;
 434         if (ret)
 435                 device_remove_file(dev, &dev_attr_online);
 436
 437         return ret;
 438 }
 439
 440 static int
 441 ccwgroup_remove (struct device *dev)
 442 {
 443         struct ccwgroup_device *gdev;
 444         struct ccwgroup_driver *gdrv;
 445
 446         gdev = to_ccwgroupdev(dev);
 447         gdrv = to_ccwgroupdrv(dev->driver);
 448
 449         device_remove_file(dev, &dev_attr_online);
 450
 451         if (gdrv && gdrv->remove)
 452                 gdrv->remove(gdev);
 453         return 0;
 454 }
 455
 456 static void ccwgroup_shutdown(struct device *dev)
 457 {
 458         struct ccwgroup_device *gdev;
 459         struct ccwgroup_driver *gdrv;
 460
 461         gdev = to_ccwgroupdev(dev);
 462         gdrv = to_ccwgroupdrv(dev->driver);
 463         if (gdrv && gdrv->shutdown)
 464                 gdrv->shutdown(gdev);
 465 }
 466
 467 static struct bus_type ccwgroup_bus_type = {
 468         .name   = "ccwgroup",
 469         .match  = ccwgroup_bus_match,
 470         .uevent = ccwgroup_uevent,
 471         .probe  = ccwgroup_probe,
 472         .remove = ccwgroup_remove,
 473         .shutdown = ccwgroup_shutdown,
 474 };
 475
 476 /**
 477  * ccwgroup_driver_register() - register a ccw group driver
 478  * @cdriver: driver to be registered
 479  *
 480  * This function is mainly a wrapper around driver_register().
 481  */
 482 int ccwgroup_driver_register(struct ccwgroup_driver *cdriver)
 483 {
 484         /* register our new driver with the core */
 485         cdriver->driver.bus = &ccwgroup_bus_type;
 486         cdriver->driver.name = cdriver->name;
 487         cdriver->driver.owner = cdriver->owner;
 488
 489         return driver_register(&cdriver->driver);
 490 }
 491
 492 static int
 493 __ccwgroup_match_all(struct device *dev, void *data)
 494 {
 495         return 1;
 496 }
 497
 498 /**
 499  * ccwgroup_driver_unregister() - deregister a ccw group driver
 500  * @cdriver: driver to be deregistered
 501  *
 502  * This function is mainly a wrapper around driver_unregister().
 503  */
 504 void ccwgroup_driver_unregister(struct ccwgroup_driver *cdriver)
 505 {
 506         struct device *dev;
 507
 508         /* We don't want ccwgroup devices to live longer than their driver. */
 509         get_driver(&cdriver->driver);
 510         while ((dev = driver_find_device(&cdriver->driver, NULL, NULL,
 511                                          __ccwgroup_match_all))) {
 512                 struct ccwgroup_device *gdev = to_ccwgroupdev(dev);
 513
 514                 mutex_lock(&gdev->reg_mutex);
 515                 __ccwgroup_remove_symlinks(gdev);
 516                 device_unregister(dev);
 517                 mutex_unlock(&gdev->reg_mutex);
 518                 put_device(dev);
 519         }
 520         put_driver(&cdriver->driver);
 521         driver_unregister(&cdriver->driver);
 522 }
 523
 524 /**
 525  * ccwgroup_probe_ccwdev() - probe function for slave devices
 526  * @cdev: ccw device to be probed
 527  *
 528  * This is a dummy probe function for ccw devices that are slave devices in
 529  * a ccw group device.
 530  * Returns:
 531  *  always %0
 532  */
 533 int ccwgroup_probe_ccwdev(struct ccw_device *cdev)
 534 {
 535         return 0;
 536 }
 537
 538 static struct ccwgroup_device *
 539 __ccwgroup_get_gdev_by_cdev(struct ccw_device *cdev)
 540 {
 541         struct ccwgroup_device *gdev;
 542
 543         gdev = dev_get_drvdata(&cdev->dev);
 544         if (gdev) {
 545                 if (get_device(&gdev->dev)) {
 546                         mutex_lock(&gdev->reg_mutex);
 547                         if (device_is_registered(&gdev->dev))
 548                                 return gdev;
 549                         mutex_unlock(&gdev->reg_mutex);
 550                         put_device(&gdev->dev);
 551                 }
 552                 return NULL;
 553         }
 554         return NULL;
 555 }
 556
 557 /**
 558  * ccwgroup_remove_ccwdev() - remove function for slave devices
 559  * @cdev: ccw device to be removed
 560  *
 561  * This is a remove function for ccw devices that are slave devices in a ccw
 562  * group device. It sets the ccw device offline and also deregisters the
 563  * embedding ccw group device.
 564  */
 565 void ccwgroup_remove_ccwdev(struct ccw_device *cdev)
 566 {
 567         struct ccwgroup_device *gdev;
 568
 569         /* Ignore offlining errors, device is gone anyway. */
 570         ccw_device_set_offline(cdev);
 571         /* If one of its devices is gone, the whole group is done for. */
 572         gdev = __ccwgroup_get_gdev_by_cdev(cdev);
 573         if (gdev) {
 574                 __ccwgroup_remove_symlinks(gdev);
 575                 device_unregister(&gdev->dev);
 576                 mutex_unlock(&gdev->reg_mutex);
 577                 put_device(&gdev->dev);
 578         }
 579 }
 580
 581 MODULE_LICENSE("GPL");
 582 EXPORT_SYMBOL(ccwgroup_driver_register);
 583 EXPORT_SYMBOL(ccwgroup_driver_unregister);
 584 EXPORT_SYMBOL(ccwgroup_probe_ccwdev);
 585 EXPORT_SYMBOL(ccwgroup_remove_ccwdev);