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 #define CCW_BUS_ID_SIZE         20
  23
  24 /* In Linux 2.4, we had a channel device layer called "chandev"
  25  * that did all sorts of obscure stuff for networking devices.
  26  * This is another driver that serves as a replacement for just
  27  * one of its functions, namely the translation of single subchannels
  28  * to devices that use multiple subchannels.
  29  */
  30
  31 /* a device matches a driver if all its slave devices match the same
  32  * entry of the driver */
  33 static int
  34 ccwgroup_bus_match (struct device * dev, struct device_driver * drv)
  35 {
  36         struct ccwgroup_device *gdev;
  37         struct ccwgroup_driver *gdrv;
  38
  39         gdev = to_ccwgroupdev(dev);
  40         gdrv = to_ccwgroupdrv(drv);
  41
  42         if (gdev->creator_id == gdrv->driver_id)
  43                 return 1;
  44
  45         return 0;
  46 }
  47 static int
  48 ccwgroup_uevent (struct device *dev, struct kobj_uevent_env *env)
  49 {
  50         /* TODO */
  51         return 0;
  52 }
  53
  54 static struct bus_type ccwgroup_bus_type;
  55
  56 static void
  57 __ccwgroup_remove_symlinks(struct ccwgroup_device *gdev)
  58 {
  59         int i;
  60         char str[8];
  61
  62         for (i = 0; i < gdev->count; i++) {
  63                 sprintf(str, "cdev%d", i);
  64                 sysfs_remove_link(&gdev->dev.kobj, str);
  65                 sysfs_remove_link(&gdev->cdev[i]->dev.kobj, "group_device");
  66         }
  67
  68 }
  69
  70 /*
  71  * Provide an 'ungroup' attribute so the user can remove group devices no
  72  * longer needed or accidentially created. Saves memory :)
  73  */
  74 static void ccwgroup_ungroup_callback(struct device *dev)
  75 {
  76         struct ccwgroup_device *gdev = to_ccwgroupdev(dev);
  77
  78         mutex_lock(&gdev->reg_mutex);
  79         if (device_is_registered(&gdev->dev)) {
  80                 __ccwgroup_remove_symlinks(gdev);
  81                 device_unregister(dev);
  82         }
  83         mutex_unlock(&gdev->reg_mutex);
  84 }
  85
  86 static ssize_t
  87 ccwgroup_ungroup_store(struct device *dev, struct device_attribute *attr, const char *buf, size_t count)
  88 {
  89         struct ccwgroup_device *gdev;
  90         int rc;
  91
  92         gdev = to_ccwgroupdev(dev);
  93
  94         /* Prevent concurrent online/offline processing and ungrouping. */
  95         if (atomic_cmpxchg(&gdev->onoff, 0, 1) != 0)
  96                 return -EAGAIN;
  97         if (gdev->state != CCWGROUP_OFFLINE) {
  98                 rc = -EINVAL;
  99                 goto out;
 100         }
 101         /* Note that we cannot unregister the device from one of its
 102          * attribute methods, so we have to use this roundabout approach.
 103          */
 104         rc = device_schedule_callback(dev, ccwgroup_ungroup_callback);
 105 out:
 106         if (rc) {
 107                 if (rc != -EAGAIN)
 108                         /* Release onoff "lock" when ungrouping failed. */
 109                         atomic_set(&gdev->onoff, 0);
 110                 return rc;
 111         }
 112         return count;
 113 }
 114
 115 static DEVICE_ATTR(ungroup, 0200, NULL, ccwgroup_ungroup_store);
 116
 117 static void
 118 ccwgroup_release (struct device *dev)
 119 {
 120         struct ccwgroup_device *gdev;
 121         int i;
 122
 123         gdev = to_ccwgroupdev(dev);
 124
 125         for (i = 0; i < gdev->count; i++) {
 126                 if (gdev->cdev[i]) {
 127                         if (dev_get_drvdata(&gdev->cdev[i]->dev) == gdev)
 128                                 dev_set_drvdata(&gdev->cdev[i]->dev, NULL);
 129                         put_device(&gdev->cdev[i]->dev);
 130                 }
 131         }
 132         kfree(gdev);
 133 }
 134
 135 static int
 136 __ccwgroup_create_symlinks(struct ccwgroup_device *gdev)
 137 {
 138         char str[8];
 139         int i, rc;
 140
 141         for (i = 0; i < gdev->count; i++) {
 142                 rc = sysfs_create_link(&gdev->cdev[i]->dev.kobj, &gdev->dev.kobj,
 143                                        "group_device");
 144                 if (rc) {
 145                         for (--i; i >= 0; i--)
 146                                 sysfs_remove_link(&gdev->cdev[i]->dev.kobj,
 147                                                   "group_device");
 148                         return rc;
 149                 }
 150         }
 151         for (i = 0; i < gdev->count; i++) {
 152                 sprintf(str, "cdev%d", i);
 153                 rc = sysfs_create_link(&gdev->dev.kobj, &gdev->cdev[i]->dev.kobj,
 154                                        str);
 155                 if (rc) {
 156                         for (--i; i >= 0; i--) {
 157                                 sprintf(str, "cdev%d", i);
 158                                 sysfs_remove_link(&gdev->dev.kobj, str);
 159                         }
 160                         for (i = 0; i < gdev->count; i++)
 161                                 sysfs_remove_link(&gdev->cdev[i]->dev.kobj,
 162                                                   "group_device");
 163                         return rc;
 164                 }
 165         }
 166         return 0;
 167 }
 168
 169 static int __get_next_bus_id(const char **buf, char *bus_id)
 170 {
 171         int rc, len;
 172         char *start, *end;
 173
 174         start = (char *)*buf;
 175         end = strchr(start, ',');
 176         if (!end) {
 177                 /* Last entry. Strip trailing newline, if applicable. */
 178                 end = strchr(start, '\n');
 179                 if (end)
 180                         *end = '\0';
 181                 len = strlen(start) + 1;
 182         } else {
 183                 len = end - start + 1;
 184                 end++;
 185         }
 186         if (len < CCW_BUS_ID_SIZE) {
 187                 strlcpy(bus_id, start, len);
 188                 rc = 0;
 189         } else
 190                 rc = -EINVAL;
 191         *buf = end;
 192         return rc;
 193 }
 194
 195 static int __is_valid_bus_id(char bus_id[CCW_BUS_ID_SIZE])
 196 {
 197         int cssid, ssid, devno;
 198
 199         /* Must be of form %x.%x.%04x */
 200         if (sscanf(bus_id, "%x.%1x.%04x", &cssid, &ssid, &devno) != 3)
 201                 return 0;
 202         return 1;
 203 }
 204
 205 /**
 206  * ccwgroup_create_from_string() - create and register a ccw group device
 207  * @root: parent device for the new device
 208  * @creator_id: identifier of creating driver
 209  * @cdrv: ccw driver of slave devices
 210  * @num_devices: number of slave devices
 211  * @buf: buffer containing comma separated bus ids of slave devices
 212  *
 213  * Create and register a new ccw group device as a child of @root. Slave
 214  * devices are obtained from the list of bus ids given in @buf and must all
 215  * belong to @cdrv.
 216  * Returns:
 217  *  %0 on success and an error code on failure.
 218  * Context:
 219  *  non-atomic
 220  */
 221 int ccwgroup_create_from_string(struct device *root, unsigned int creator_id,
 222                                 struct ccw_driver *cdrv, int num_devices,
 223                                 const char *buf)
 224 {
 225         struct ccwgroup_device *gdev;
 226         int rc, i;
 227         char tmp_bus_id[CCW_BUS_ID_SIZE];
 228         const char *curr_buf;
 229
 230         gdev = kzalloc(sizeof(*gdev) + num_devices * sizeof(gdev->cdev[0]),
 231                        GFP_KERNEL);
 232         if (!gdev)
 233                 return -ENOMEM;
 234
 235         atomic_set(&gdev->onoff, 0);
 236         mutex_init(&gdev->reg_mutex);
 237         mutex_lock(&gdev->reg_mutex);
 238         gdev->creator_id = creator_id;
 239         gdev->count = num_devices;
 240         gdev->dev.bus = &ccwgroup_bus_type;
 241         gdev->dev.parent = root;
 242         gdev->dev.release = ccwgroup_release;
 243         device_initialize(&gdev->dev);
 244
 245         curr_buf = buf;
 246         for (i = 0; i < num_devices && curr_buf; i++) {
 247                 rc = __get_next_bus_id(&curr_buf, tmp_bus_id);
 248                 if (rc != 0)
 249                         goto error;
 250                 if (!__is_valid_bus_id(tmp_bus_id)) {
 251                         rc = -EINVAL;
 252                         goto error;
 253                 }
 254                 gdev->cdev[i] = get_ccwdev_by_busid(cdrv, tmp_bus_id);
 255                 /*
 256                  * All devices have to be of the same type in
 257                  * order to be grouped.
 258                  */
 259                 if (!gdev->cdev[i]
 260                     || gdev->cdev[i]->id.driver_info !=
 261                     gdev->cdev[0]->id.driver_info) {
 262                         rc = -EINVAL;
 263                         goto error;
 264                 }
 265                 /* Don't allow a device to belong to more than one group. */
 266                 if (dev_get_drvdata(&gdev->cdev[i]->dev)) {
 267                         rc = -EINVAL;
 268                         goto error;
 269                 }
 270                 dev_set_drvdata(&gdev->cdev[i]->dev, gdev);
 271         }
 272         /* Check for sufficient number of bus ids. */
 273         if (i < num_devices && !curr_buf) {
 274                 rc = -EINVAL;
 275                 goto error;
 276         }
 277         /* Check for trailing stuff. */
 278         if (i == num_devices && strlen(curr_buf) > 0) {
 279                 rc = -EINVAL;
 280                 goto error;
 281         }
 282
 283         dev_set_name(&gdev->dev, "%s", dev_name(&gdev->cdev[0]->dev));
 284
 285         rc = device_add(&gdev->dev);
 286         if (rc)
 287                 goto error;
 288         get_device(&gdev->dev);
 289         rc = device_create_file(&gdev->dev, &dev_attr_ungroup);
 290
 291         if (rc) {
 292                 device_unregister(&gdev->dev);
 293                 goto error;
 294         }
 295
 296         rc = __ccwgroup_create_symlinks(gdev);
 297         if (!rc) {
 298                 mutex_unlock(&gdev->reg_mutex);
 299                 put_device(&gdev->dev);
 300                 return 0;
 301         }
 302         device_remove_file(&gdev->dev, &dev_attr_ungroup);
 303         device_unregister(&gdev->dev);
 304 error:
 305         for (i = 0; i < num_devices; i++)
 306                 if (gdev->cdev[i]) {
 307                         if (dev_get_drvdata(&gdev->cdev[i]->dev) == gdev)
 308                                 dev_set_drvdata(&gdev->cdev[i]->dev, NULL);
 309                         put_device(&gdev->cdev[i]->dev);
 310                         gdev->cdev[i] = NULL;
 311                 }
 312         mutex_unlock(&gdev->reg_mutex);
 313         put_device(&gdev->dev);
 314         return rc;
 315 }
 316 EXPORT_SYMBOL(ccwgroup_create_from_string);
 317
 318 static int __init
 319 init_ccwgroup (void)
 320 {
 321         return bus_register (&ccwgroup_bus_type);
 322 }
 323
 324 static void __exit
 325 cleanup_ccwgroup (void)
 326 {
 327         bus_unregister (&ccwgroup_bus_type);
 328 }
 329
 330 module_init(init_ccwgroup);
 331 module_exit(cleanup_ccwgroup);
 332
 333 /************************** driver stuff ******************************/
 334
 335 static int
 336 ccwgroup_set_online(struct ccwgroup_device *gdev)
 337 {
 338         struct ccwgroup_driver *gdrv;
 339         int ret;
 340
 341         if (atomic_cmpxchg(&gdev->onoff, 0, 1) != 0)
 342                 return -EAGAIN;
 343         if (gdev->state == CCWGROUP_ONLINE) {
 344                 ret = 0;
 345                 goto out;
 346         }
 347         if (!gdev->dev.driver) {
 348                 ret = -EINVAL;
 349                 goto out;
 350         }
 351         gdrv = to_ccwgroupdrv (gdev->dev.driver);
 352         if ((ret = gdrv->set_online ? gdrv->set_online(gdev) : 0))
 353                 goto out;
 354
 355         gdev->state = CCWGROUP_ONLINE;
 356  out:
 357         atomic_set(&gdev->onoff, 0);
 358         return ret;
 359 }
 360
 361 static int
 362 ccwgroup_set_offline(struct ccwgroup_device *gdev)
 363 {
 364         struct ccwgroup_driver *gdrv;
 365         int ret;
 366
 367         if (atomic_cmpxchg(&gdev->onoff, 0, 1) != 0)
 368                 return -EAGAIN;
 369         if (gdev->state == CCWGROUP_OFFLINE) {
 370                 ret = 0;
 371                 goto out;
 372         }
 373         if (!gdev->dev.driver) {
 374                 ret = -EINVAL;
 375                 goto out;
 376         }
 377         gdrv = to_ccwgroupdrv (gdev->dev.driver);
 378         if ((ret = gdrv->set_offline ? gdrv->set_offline(gdev) : 0))
 379                 goto out;
 380
 381         gdev->state = CCWGROUP_OFFLINE;
 382  out:
 383         atomic_set(&gdev->onoff, 0);
 384         return ret;
 385 }
 386
 387 static ssize_t
 388 ccwgroup_online_store (struct device *dev, struct device_attribute *attr, const char *buf, size_t count)
 389 {
 390         struct ccwgroup_device *gdev;
 391         struct ccwgroup_driver *gdrv;
 392         unsigned long value;
 393         int ret;
 394
 395         gdev = to_ccwgroupdev(dev);
 396         if (!dev->driver)
 397                 return count;
 398
 399         gdrv = to_ccwgroupdrv (gdev->dev.driver);
 400         if (!try_module_get(gdrv->owner))
 401                 return -EINVAL;
 402
 403         ret = strict_strtoul(buf, 0, &value);
 404         if (ret)
 405                 goto out;
 406         ret = count;
 407         if (value == 1)
 408                 ccwgroup_set_online(gdev);
 409         else if (value == 0)
 410                 ccwgroup_set_offline(gdev);
 411         else
 412                 ret = -EINVAL;
 413 out:
 414         module_put(gdrv->owner);
 415         return ret;
 416 }
 417
 418 static ssize_t
 419 ccwgroup_online_show (struct device *dev, struct device_attribute *attr, char *buf)
 420 {
 421         int online;
 422
 423         online = (to_ccwgroupdev(dev)->state == CCWGROUP_ONLINE);
 424
 425         return sprintf(buf, online ? "1\n" : "0\n");
 426 }
 427
 428 static DEVICE_ATTR(online, 0644, ccwgroup_online_show, ccwgroup_online_store);
 429
 430 static int
 431 ccwgroup_probe (struct device *dev)
 432 {
 433         struct ccwgroup_device *gdev;
 434         struct ccwgroup_driver *gdrv;
 435
 436         int ret;
 437
 438         gdev = to_ccwgroupdev(dev);
 439         gdrv = to_ccwgroupdrv(dev->driver);
 440
 441         if ((ret = device_create_file(dev, &dev_attr_online)))
 442                 return ret;
 443
 444         ret = gdrv->probe ? gdrv->probe(gdev) : -ENODEV;
 445         if (ret)
 446                 device_remove_file(dev, &dev_attr_online);
 447
 448         return ret;
 449 }
 450
 451 static int
 452 ccwgroup_remove (struct device *dev)
 453 {
 454         struct ccwgroup_device *gdev;
 455         struct ccwgroup_driver *gdrv;
 456
 457         gdev = to_ccwgroupdev(dev);
 458         gdrv = to_ccwgroupdrv(dev->driver);
 459
 460         device_remove_file(dev, &dev_attr_online);
 461
 462         if (gdrv && gdrv->remove)
 463                 gdrv->remove(gdev);
 464         return 0;
 465 }
 466
 467 static void ccwgroup_shutdown(struct device *dev)
 468 {
 469         struct ccwgroup_device *gdev;
 470         struct ccwgroup_driver *gdrv;
 471
 472         gdev = to_ccwgroupdev(dev);
 473         gdrv = to_ccwgroupdrv(dev->driver);
 474         if (gdrv && gdrv->shutdown)
 475                 gdrv->shutdown(gdev);
 476 }
 477
 478 static struct bus_type ccwgroup_bus_type = {
 479         .name   = "ccwgroup",
 480         .match  = ccwgroup_bus_match,
 481         .uevent = ccwgroup_uevent,
 482         .probe  = ccwgroup_probe,
 483         .remove = ccwgroup_remove,
 484         .shutdown = ccwgroup_shutdown,
 485 };
 486
 487 /**
 488  * ccwgroup_driver_register() - register a ccw group driver
 489  * @cdriver: driver to be registered
 490  *
 491  * This function is mainly a wrapper around driver_register().
 492  */
 493 int ccwgroup_driver_register(struct ccwgroup_driver *cdriver)
 494 {
 495         /* register our new driver with the core */
 496         cdriver->driver.bus = &ccwgroup_bus_type;
 497         cdriver->driver.name = cdriver->name;
 498         cdriver->driver.owner = cdriver->owner;
 499
 500         return driver_register(&cdriver->driver);
 501 }
 502
 503 static int
 504 __ccwgroup_match_all(struct device *dev, void *data)
 505 {
 506         return 1;
 507 }
 508
 509 /**
 510  * ccwgroup_driver_unregister() - deregister a ccw group driver
 511  * @cdriver: driver to be deregistered
 512  *
 513  * This function is mainly a wrapper around driver_unregister().
 514  */
 515 void ccwgroup_driver_unregister(struct ccwgroup_driver *cdriver)
 516 {
 517         struct device *dev;
 518
 519         /* We don't want ccwgroup devices to live longer than their driver. */
 520         get_driver(&cdriver->driver);
 521         while ((dev = driver_find_device(&cdriver->driver, NULL, NULL,
 522                                          __ccwgroup_match_all))) {
 523                 struct ccwgroup_device *gdev = to_ccwgroupdev(dev);
 524
 525                 mutex_lock(&gdev->reg_mutex);
 526                 __ccwgroup_remove_symlinks(gdev);
 527                 device_unregister(dev);
 528                 mutex_unlock(&gdev->reg_mutex);
 529                 put_device(dev);
 530         }
 531         put_driver(&cdriver->driver);
 532         driver_unregister(&cdriver->driver);
 533 }
 534
 535 /**
 536  * ccwgroup_probe_ccwdev() - probe function for slave devices
 537  * @cdev: ccw device to be probed
 538  *
 539  * This is a dummy probe function for ccw devices that are slave devices in
 540  * a ccw group device.
 541  * Returns:
 542  *  always %0
 543  */
 544 int ccwgroup_probe_ccwdev(struct ccw_device *cdev)
 545 {
 546         return 0;
 547 }
 548
 549 static struct ccwgroup_device *
 550 __ccwgroup_get_gdev_by_cdev(struct ccw_device *cdev)
 551 {
 552         struct ccwgroup_device *gdev;
 553
 554         gdev = dev_get_drvdata(&cdev->dev);
 555         if (gdev) {
 556                 if (get_device(&gdev->dev)) {
 557                         mutex_lock(&gdev->reg_mutex);
 558                         if (device_is_registered(&gdev->dev))
 559                                 return gdev;
 560                         mutex_unlock(&gdev->reg_mutex);
 561                         put_device(&gdev->dev);
 562                 }
 563                 return NULL;
 564         }
 565         return NULL;
 566 }
 567
 568 /**
 569  * ccwgroup_remove_ccwdev() - remove function for slave devices
 570  * @cdev: ccw device to be removed
 571  *
 572  * This is a remove function for ccw devices that are slave devices in a ccw
 573  * group device. It sets the ccw device offline and also deregisters the
 574  * embedding ccw group device.
 575  */
 576 void ccwgroup_remove_ccwdev(struct ccw_device *cdev)
 577 {
 578         struct ccwgroup_device *gdev;
 579
 580         /* Ignore offlining errors, device is gone anyway. */
 581         ccw_device_set_offline(cdev);
 582         /* If one of its devices is gone, the whole group is done for. */
 583         gdev = __ccwgroup_get_gdev_by_cdev(cdev);
 584         if (gdev) {
 585                 __ccwgroup_remove_symlinks(gdev);
 586                 device_unregister(&gdev->dev);
 587                 mutex_unlock(&gdev->reg_mutex);
 588                 put_device(&gdev->dev);
 589         }
 590 }
 591
 592 MODULE_LICENSE("GPL");
 593 EXPORT_SYMBOL(ccwgroup_driver_register);
 594 EXPORT_SYMBOL(ccwgroup_driver_unregister);
 595 EXPORT_SYMBOL(ccwgroup_probe_ccwdev);
 596 EXPORT_SYMBOL(ccwgroup_remove_ccwdev);