drivers/s390/cio/ccwgroup.c

   1 /*
   2  *  bus driver for ccwgroup
   3  *
   4  *  Copyright IBM Corp. 2002, 2012
   5  *
   6  *  Author(s): Arnd Bergmann (arndb@de.ibm.com)
   7  *             Cornelia Huck (cornelia.huck@de.ibm.com)
   8  */
   9 #include <linux/module.h>
  10 #include <linux/errno.h>
  11 #include <linux/slab.h>
  12 #include <linux/list.h>
  13 #include <linux/device.h>
  14 #include <linux/init.h>
  15 #include <linux/ctype.h>
  16 #include <linux/dcache.h>
  17
  18 #include <asm/cio.h>
  19 #include <asm/ccwdev.h>
  20 #include <asm/ccwgroup.h>
  21
  22 #include "device.h"
  23
  24 #define CCW_BUS_ID_SIZE         10
  25
  26 /* In Linux 2.4, we had a channel device layer called "chandev"
  27  * that did all sorts of obscure stuff for networking devices.
  28  * This is another driver that serves as a replacement for just
  29  * one of its functions, namely the translation of single subchannels
  30  * to devices that use multiple subchannels.
  31  */
  32
  33 static struct bus_type ccwgroup_bus_type;
  34
  35 static void __ccwgroup_remove_symlinks(struct ccwgroup_device *gdev)
  36 {
  37         int i;
  38         char str[8];
  39
  40         for (i = 0; i < gdev->count; i++) {
  41                 sprintf(str, "cdev%d", i);
  42                 sysfs_remove_link(&gdev->dev.kobj, str);
  43                 sysfs_remove_link(&gdev->cdev[i]->dev.kobj, "group_device");
  44         }
  45 }
  46
  47 /*
  48  * Remove references from ccw devices to ccw group device and from
  49  * ccw group device to ccw devices.
  50  */
  51 static void __ccwgroup_remove_cdev_refs(struct ccwgroup_device *gdev)
  52 {
  53         struct ccw_device *cdev;
  54         int i;
  55
  56         for (i = 0; i < gdev->count; i++) {
  57                 cdev = gdev->cdev[i];
  58                 if (!cdev)
  59                         continue;
  60                 spin_lock_irq(cdev->ccwlock);
  61                 dev_set_drvdata(&cdev->dev, NULL);
  62                 spin_unlock_irq(cdev->ccwlock);
  63                 gdev->cdev[i] = NULL;
  64                 put_device(&cdev->dev);
  65         }
  66 }
  67
  68 static int ccwgroup_set_online(struct ccwgroup_device *gdev)
  69 {
  70         struct ccwgroup_driver *gdrv = to_ccwgroupdrv(gdev->dev.driver);
  71         int ret = 0;
  72
  73         if (atomic_cmpxchg(&gdev->onoff, 0, 1) != 0)
  74                 return -EAGAIN;
  75         if (gdev->state == CCWGROUP_ONLINE)
  76                 goto out;
  77         if (gdrv->set_online)
  78                 ret = gdrv->set_online(gdev);
  79         if (ret)
  80                 goto out;
  81
  82         gdev->state = CCWGROUP_ONLINE;
  83 out:
  84         atomic_set(&gdev->onoff, 0);
  85         return ret;
  86 }
  87
  88 static int ccwgroup_set_offline(struct ccwgroup_device *gdev)
  89 {
  90         struct ccwgroup_driver *gdrv = to_ccwgroupdrv(gdev->dev.driver);
  91         int ret = 0;
  92
  93         if (atomic_cmpxchg(&gdev->onoff, 0, 1) != 0)
  94                 return -EAGAIN;
  95         if (gdev->state == CCWGROUP_OFFLINE)
  96                 goto out;
  97         if (gdrv->set_offline)
  98                 ret = gdrv->set_offline(gdev);
  99         if (ret)
 100                 goto out;
 101
 102         gdev->state = CCWGROUP_OFFLINE;
 103 out:
 104         atomic_set(&gdev->onoff, 0);
 105         return ret;
 106 }
 107
 108 static ssize_t ccwgroup_online_store(struct device *dev,
 109                                      struct device_attribute *attr,
 110                                      const char *buf, size_t count)
 111 {
 112         struct ccwgroup_device *gdev = to_ccwgroupdev(dev);
 113         struct ccwgroup_driver *gdrv = to_ccwgroupdrv(dev->driver);
 114         unsigned long value;
 115         int ret;
 116
 117         if (!dev->driver)
 118                 return -EINVAL;
 119         if (!try_module_get(gdrv->driver.owner))
 120                 return -EINVAL;
 121
 122         ret = strict_strtoul(buf, 0, &value);
 123         if (ret)
 124                 goto out;
 125
 126         if (value == 1)
 127                 ret = ccwgroup_set_online(gdev);
 128         else if (value == 0)
 129                 ret = ccwgroup_set_offline(gdev);
 130         else
 131                 ret = -EINVAL;
 132 out:
 133         module_put(gdrv->driver.owner);
 134         return (ret == 0) ? count : ret;
 135 }
 136
 137 static ssize_t ccwgroup_online_show(struct device *dev,
 138                                     struct device_attribute *attr,
 139                                     char *buf)
 140 {
 141         struct ccwgroup_device *gdev = to_ccwgroupdev(dev);
 142         int online;
 143
 144         online = (gdev->state == CCWGROUP_ONLINE) ? 1 : 0;
 145
 146         return scnprintf(buf, PAGE_SIZE, "%d\n", online);
 147 }
 148
 149 /*
 150  * Provide an 'ungroup' attribute so the user can remove group devices no
 151  * longer needed or accidentially created. Saves memory :)
 152  */
 153 static void ccwgroup_ungroup_callback(struct device *dev)
 154 {
 155         struct ccwgroup_device *gdev = to_ccwgroupdev(dev);
 156
 157         mutex_lock(&gdev->reg_mutex);
 158         if (device_is_registered(&gdev->dev)) {
 159                 __ccwgroup_remove_symlinks(gdev);
 160                 device_unregister(dev);
 161                 __ccwgroup_remove_cdev_refs(gdev);
 162         }
 163         mutex_unlock(&gdev->reg_mutex);
 164 }
 165
 166 static ssize_t ccwgroup_ungroup_store(struct device *dev,
 167                                       struct device_attribute *attr,
 168                                       const char *buf, size_t count)
 169 {
 170         struct ccwgroup_device *gdev = to_ccwgroupdev(dev);
 171         int rc;
 172
 173         /* Prevent concurrent online/offline processing and ungrouping. */
 174         if (atomic_cmpxchg(&gdev->onoff, 0, 1) != 0)
 175                 return -EAGAIN;
 176         if (gdev->state != CCWGROUP_OFFLINE) {
 177                 rc = -EINVAL;
 178                 goto out;
 179         }
 180         /* Note that we cannot unregister the device from one of its
 181          * attribute methods, so we have to use this roundabout approach.
 182          */
 183         rc = device_schedule_callback(dev, ccwgroup_ungroup_callback);
 184 out:
 185         if (rc) {
 186                 if (rc != -EAGAIN)
 187                         /* Release onoff "lock" when ungrouping failed. */
 188                         atomic_set(&gdev->onoff, 0);
 189                 return rc;
 190         }
 191         return count;
 192 }
 193 static DEVICE_ATTR(ungroup, 0200, NULL, ccwgroup_ungroup_store);
 194 static DEVICE_ATTR(online, 0644, ccwgroup_online_show, ccwgroup_online_store);
 195
 196 static struct attribute *ccwgroup_attrs[] = {
 197         &dev_attr_online.attr,
 198         &dev_attr_ungroup.attr,
 199         NULL,
 200 };
 201 static struct attribute_group ccwgroup_attr_group = {
 202         .attrs = ccwgroup_attrs,
 203 };
 204 static const struct attribute_group *ccwgroup_attr_groups[] = {
 205         &ccwgroup_attr_group,
 206         NULL,
 207 };
 208
 209 static void ccwgroup_release(struct device *dev)
 210 {
 211         kfree(to_ccwgroupdev(dev));
 212 }
 213
 214 static int __ccwgroup_create_symlinks(struct ccwgroup_device *gdev)
 215 {
 216         char str[8];
 217         int i, rc;
 218
 219         for (i = 0; i < gdev->count; i++) {
 220                 rc = sysfs_create_link(&gdev->cdev[i]->dev.kobj,
 221                                        &gdev->dev.kobj, "group_device");
 222                 if (rc) {
 223                         for (--i; i >= 0; i--)
 224                                 sysfs_remove_link(&gdev->cdev[i]->dev.kobj,
 225                                                   "group_device");
 226                         return rc;
 227                 }
 228         }
 229         for (i = 0; i < gdev->count; i++) {
 230                 sprintf(str, "cdev%d", i);
 231                 rc = sysfs_create_link(&gdev->dev.kobj,
 232                                        &gdev->cdev[i]->dev.kobj, str);
 233                 if (rc) {
 234                         for (--i; i >= 0; i--) {
 235                                 sprintf(str, "cdev%d", i);
 236                                 sysfs_remove_link(&gdev->dev.kobj, str);
 237                         }
 238                         for (i = 0; i < gdev->count; i++)
 239                                 sysfs_remove_link(&gdev->cdev[i]->dev.kobj,
 240                                                   "group_device");
 241                         return rc;
 242                 }
 243         }
 244         return 0;
 245 }
 246
 247 static int __get_next_id(const char **buf, struct ccw_dev_id *id)
 248 {
 249         unsigned int cssid, ssid, devno;
 250         int ret = 0, len;
 251         char *start, *end;
 252
 253         start = (char *)*buf;
 254         end = strchr(start, ',');
 255         if (!end) {
 256                 /* Last entry. Strip trailing newline, if applicable. */
 257                 end = strchr(start, '\n');
 258                 if (end)
 259                         *end = '\0';
 260                 len = strlen(start) + 1;
 261         } else {
 262                 len = end - start + 1;
 263                 end++;
 264         }
 265         if (len <= CCW_BUS_ID_SIZE) {
 266                 if (sscanf(start, "%2x.%1x.%04x", &cssid, &ssid, &devno) != 3)
 267                         ret = -EINVAL;
 268         } else
 269                 ret = -EINVAL;
 270
 271         if (!ret) {
 272                 id->ssid = ssid;
 273                 id->devno = devno;
 274         }
 275         *buf = end;
 276         return ret;
 277 }
 278
 279 /**
 280  * ccwgroup_create_dev() - create and register a ccw group device
 281  * @parent: parent device for the new device
 282  * @gdrv: driver for the new group device
 283  * @num_devices: number of slave devices
 284  * @buf: buffer containing comma separated bus ids of slave devices
 285  *
 286  * Create and register a new ccw group device as a child of @parent. Slave
 287  * devices are obtained from the list of bus ids given in @buf.
 288  * Returns:
 289  *  %0 on success and an error code on failure.
 290  * Context:
 291  *  non-atomic
 292  */
 293 int ccwgroup_create_dev(struct device *parent, struct ccwgroup_driver *gdrv,
 294                         int num_devices, const char *buf)
 295 {
 296         struct ccwgroup_device *gdev;
 297         struct ccw_dev_id dev_id;
 298         int rc, i;
 299
 300         gdev = kzalloc(sizeof(*gdev) + num_devices * sizeof(gdev->cdev[0]),
 301                        GFP_KERNEL);
 302         if (!gdev)
 303                 return -ENOMEM;
 304
 305         atomic_set(&gdev->onoff, 0);
 306         mutex_init(&gdev->reg_mutex);
 307         mutex_lock(&gdev->reg_mutex);
 308         gdev->count = num_devices;
 309         gdev->dev.bus = &ccwgroup_bus_type;
 310         gdev->dev.parent = parent;
 311         gdev->dev.release = ccwgroup_release;
 312         device_initialize(&gdev->dev);
 313
 314         for (i = 0; i < num_devices && buf; i++) {
 315                 rc = __get_next_id(&buf, &dev_id);
 316                 if (rc != 0)
 317                         goto error;
 318                 gdev->cdev[i] = get_ccwdev_by_dev_id(&dev_id);
 319                 /*
 320                  * All devices have to be of the same type in
 321                  * order to be grouped.
 322                  */
 323                 if (!gdev->cdev[i] || !gdev->cdev[i]->drv ||
 324                     gdev->cdev[i]->drv != gdev->cdev[0]->drv ||
 325                     gdev->cdev[i]->id.driver_info !=
 326                     gdev->cdev[0]->id.driver_info) {
 327                         rc = -EINVAL;
 328                         goto error;
 329                 }
 330                 /* Don't allow a device to belong to more than one group. */
 331                 spin_lock_irq(gdev->cdev[i]->ccwlock);
 332                 if (dev_get_drvdata(&gdev->cdev[i]->dev)) {
 333                         spin_unlock_irq(gdev->cdev[i]->ccwlock);
 334                         rc = -EINVAL;
 335                         goto error;
 336                 }
 337                 dev_set_drvdata(&gdev->cdev[i]->dev, gdev);
 338                 spin_unlock_irq(gdev->cdev[i]->ccwlock);
 339         }
 340         /* Check for sufficient number of bus ids. */
 341         if (i < num_devices) {
 342                 rc = -EINVAL;
 343                 goto error;
 344         }
 345         /* Check for trailing stuff. */
 346         if (i == num_devices && strlen(buf) > 0) {
 347                 rc = -EINVAL;
 348                 goto error;
 349         }
 350
 351         dev_set_name(&gdev->dev, "%s", dev_name(&gdev->cdev[0]->dev));
 352         gdev->dev.groups = ccwgroup_attr_groups;
 353
 354         if (gdrv) {
 355                 gdev->dev.driver = &gdrv->driver;
 356                 rc = gdrv->setup ? gdrv->setup(gdev) : 0;
 357                 if (rc)
 358                         goto error;
 359         }
 360         rc = device_add(&gdev->dev);
 361         if (rc)
 362                 goto error;
 363         rc = __ccwgroup_create_symlinks(gdev);
 364         if (rc) {
 365                 device_del(&gdev->dev);
 366                 goto error;
 367         }
 368         mutex_unlock(&gdev->reg_mutex);
 369         return 0;
 370 error:
 371         for (i = 0; i < num_devices; i++)
 372                 if (gdev->cdev[i]) {
 373                         spin_lock_irq(gdev->cdev[i]->ccwlock);
 374                         if (dev_get_drvdata(&gdev->cdev[i]->dev) == gdev)
 375                                 dev_set_drvdata(&gdev->cdev[i]->dev, NULL);
 376                         spin_unlock_irq(gdev->cdev[i]->ccwlock);
 377                         put_device(&gdev->cdev[i]->dev);
 378                         gdev->cdev[i] = NULL;
 379                 }
 380         mutex_unlock(&gdev->reg_mutex);
 381         put_device(&gdev->dev);
 382         return rc;
 383 }
 384 EXPORT_SYMBOL(ccwgroup_create_dev);
 385
 386 static int ccwgroup_notifier(struct notifier_block *nb, unsigned long action,
 387                              void *data)
 388 {
 389         struct device *dev = data;
 390
 391         if (action == BUS_NOTIFY_UNBIND_DRIVER)
 392                 device_schedule_callback(dev, ccwgroup_ungroup_callback);
 393
 394         return NOTIFY_OK;
 395 }
 396
 397 static struct notifier_block ccwgroup_nb = {
 398         .notifier_call = ccwgroup_notifier
 399 };
 400
 401 static int __init init_ccwgroup(void)
 402 {
 403         int ret;
 404
 405         ret = bus_register(&ccwgroup_bus_type);
 406         if (ret)
 407                 return ret;
 408
 409         ret = bus_register_notifier(&ccwgroup_bus_type, &ccwgroup_nb);
 410         if (ret)
 411                 bus_unregister(&ccwgroup_bus_type);
 412
 413         return ret;
 414 }
 415
 416 static void __exit cleanup_ccwgroup(void)
 417 {
 418         bus_unregister_notifier(&ccwgroup_bus_type, &ccwgroup_nb);
 419         bus_unregister(&ccwgroup_bus_type);
 420 }
 421
 422 module_init(init_ccwgroup);
 423 module_exit(cleanup_ccwgroup);
 424
 425 /************************** driver stuff ******************************/
 426
 427 static int ccwgroup_remove(struct device *dev)
 428 {
 429         struct ccwgroup_device *gdev = to_ccwgroupdev(dev);
 430         struct ccwgroup_driver *gdrv = to_ccwgroupdrv(dev->driver);
 431
 432         if (!dev->driver)
 433                 return 0;
 434         if (gdrv->remove)
 435                 gdrv->remove(gdev);
 436
 437         return 0;
 438 }
 439
 440 static void ccwgroup_shutdown(struct device *dev)
 441 {
 442         struct ccwgroup_device *gdev = to_ccwgroupdev(dev);
 443         struct ccwgroup_driver *gdrv = to_ccwgroupdrv(dev->driver);
 444
 445         if (!dev->driver)
 446                 return;
 447         if (gdrv->shutdown)
 448                 gdrv->shutdown(gdev);
 449 }
 450
 451 static int ccwgroup_pm_prepare(struct device *dev)
 452 {
 453         struct ccwgroup_device *gdev = to_ccwgroupdev(dev);
 454         struct ccwgroup_driver *gdrv = to_ccwgroupdrv(gdev->dev.driver);
 455
 456         /* Fail while device is being set online/offline. */
 457         if (atomic_read(&gdev->onoff))
 458                 return -EAGAIN;
 459
 460         if (!gdev->dev.driver || gdev->state != CCWGROUP_ONLINE)
 461                 return 0;
 462
 463         return gdrv->prepare ? gdrv->prepare(gdev) : 0;
 464 }
 465
 466 static void ccwgroup_pm_complete(struct device *dev)
 467 {
 468         struct ccwgroup_device *gdev = to_ccwgroupdev(dev);
 469         struct ccwgroup_driver *gdrv = to_ccwgroupdrv(dev->driver);
 470
 471         if (!gdev->dev.driver || gdev->state != CCWGROUP_ONLINE)
 472                 return;
 473
 474         if (gdrv->complete)
 475                 gdrv->complete(gdev);
 476 }
 477
 478 static int ccwgroup_pm_freeze(struct device *dev)
 479 {
 480         struct ccwgroup_device *gdev = to_ccwgroupdev(dev);
 481         struct ccwgroup_driver *gdrv = to_ccwgroupdrv(gdev->dev.driver);
 482
 483         if (!gdev->dev.driver || gdev->state != CCWGROUP_ONLINE)
 484                 return 0;
 485
 486         return gdrv->freeze ? gdrv->freeze(gdev) : 0;
 487 }
 488
 489 static int ccwgroup_pm_thaw(struct device *dev)
 490 {
 491         struct ccwgroup_device *gdev = to_ccwgroupdev(dev);
 492         struct ccwgroup_driver *gdrv = to_ccwgroupdrv(gdev->dev.driver);
 493
 494         if (!gdev->dev.driver || gdev->state != CCWGROUP_ONLINE)
 495                 return 0;
 496
 497         return gdrv->thaw ? gdrv->thaw(gdev) : 0;
 498 }
 499
 500 static int ccwgroup_pm_restore(struct device *dev)
 501 {
 502         struct ccwgroup_device *gdev = to_ccwgroupdev(dev);
 503         struct ccwgroup_driver *gdrv = to_ccwgroupdrv(gdev->dev.driver);
 504
 505         if (!gdev->dev.driver || gdev->state != CCWGROUP_ONLINE)
 506                 return 0;
 507
 508         return gdrv->restore ? gdrv->restore(gdev) : 0;
 509 }
 510
 511 static const struct dev_pm_ops ccwgroup_pm_ops = {
 512         .prepare = ccwgroup_pm_prepare,
 513         .complete = ccwgroup_pm_complete,
 514         .freeze = ccwgroup_pm_freeze,
 515         .thaw = ccwgroup_pm_thaw,
 516         .restore = ccwgroup_pm_restore,
 517 };
 518
 519 static struct bus_type ccwgroup_bus_type = {
 520         .name   = "ccwgroup",
 521         .remove = ccwgroup_remove,
 522         .shutdown = ccwgroup_shutdown,
 523         .pm = &ccwgroup_pm_ops,
 524 };
 525
 526 /**
 527  * ccwgroup_driver_register() - register a ccw group driver
 528  * @cdriver: driver to be registered
 529  *
 530  * This function is mainly a wrapper around driver_register().
 531  */
 532 int ccwgroup_driver_register(struct ccwgroup_driver *cdriver)
 533 {
 534         /* register our new driver with the core */
 535         cdriver->driver.bus = &ccwgroup_bus_type;
 536
 537         return driver_register(&cdriver->driver);
 538 }
 539 EXPORT_SYMBOL(ccwgroup_driver_register);
 540
 541 static int __ccwgroup_match_all(struct device *dev, void *data)
 542 {
 543         return 1;
 544 }
 545
 546 /**
 547  * ccwgroup_driver_unregister() - deregister a ccw group driver
 548  * @cdriver: driver to be deregistered
 549  *
 550  * This function is mainly a wrapper around driver_unregister().
 551  */
 552 void ccwgroup_driver_unregister(struct ccwgroup_driver *cdriver)
 553 {
 554         struct device *dev;
 555
 556         /* We don't want ccwgroup devices to live longer than their driver. */
 557         while ((dev = driver_find_device(&cdriver->driver, NULL, NULL,
 558                                          __ccwgroup_match_all))) {
 559                 struct ccwgroup_device *gdev = to_ccwgroupdev(dev);
 560
 561                 mutex_lock(&gdev->reg_mutex);
 562                 __ccwgroup_remove_symlinks(gdev);
 563                 device_unregister(dev);
 564                 __ccwgroup_remove_cdev_refs(gdev);
 565                 mutex_unlock(&gdev->reg_mutex);
 566                 put_device(dev);
 567         }
 568         driver_unregister(&cdriver->driver);
 569 }
 570 EXPORT_SYMBOL(ccwgroup_driver_unregister);
 571
 572 /**
 573  * ccwgroup_probe_ccwdev() - probe function for slave devices
 574  * @cdev: ccw device to be probed
 575  *
 576  * This is a dummy probe function for ccw devices that are slave devices in
 577  * a ccw group device.
 578  * Returns:
 579  *  always %0
 580  */
 581 int ccwgroup_probe_ccwdev(struct ccw_device *cdev)
 582 {
 583         return 0;
 584 }
 585 EXPORT_SYMBOL(ccwgroup_probe_ccwdev);
 586
 587 /**
 588  * ccwgroup_remove_ccwdev() - remove function for slave devices
 589  * @cdev: ccw device to be removed
 590  *
 591  * This is a remove function for ccw devices that are slave devices in a ccw
 592  * group device. It sets the ccw device offline and also deregisters the
 593  * embedding ccw group device.
 594  */
 595 void ccwgroup_remove_ccwdev(struct ccw_device *cdev)
 596 {
 597         struct ccwgroup_device *gdev;
 598
 599         /* Ignore offlining errors, device is gone anyway. */
 600         ccw_device_set_offline(cdev);
 601         /* If one of its devices is gone, the whole group is done for. */
 602         spin_lock_irq(cdev->ccwlock);
 603         gdev = dev_get_drvdata(&cdev->dev);
 604         if (!gdev) {
 605                 spin_unlock_irq(cdev->ccwlock);
 606                 return;
 607         }
 608         /* Get ccwgroup device reference for local processing. */
 609         get_device(&gdev->dev);
 610         spin_unlock_irq(cdev->ccwlock);
 611         /* Unregister group device. */
 612         mutex_lock(&gdev->reg_mutex);
 613         if (device_is_registered(&gdev->dev)) {
 614                 __ccwgroup_remove_symlinks(gdev);
 615                 device_unregister(&gdev->dev);
 616                 __ccwgroup_remove_cdev_refs(gdev);
 617         }
 618         mutex_unlock(&gdev->reg_mutex);
 619         /* Release ccwgroup device reference for local processing. */
 620         put_device(&gdev->dev);
 621 }
 622 EXPORT_SYMBOL(ccwgroup_remove_ccwdev);
 623 MODULE_LICENSE("GPL");