kernel/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 /**
  69  * ccwgroup_set_online() - enable a ccwgroup device
  70  * @gdev: target ccwgroup device
  71  *
  72  * This function attempts to put the ccwgroup device into the online state.
  73  * Returns:
  74  *  %0 on success and a negative error value on failure.
  75  */
  76 int ccwgroup_set_online(struct ccwgroup_device *gdev)
  77 {
  78         struct ccwgroup_driver *gdrv = to_ccwgroupdrv(gdev->dev.driver);
  79         int ret = -EINVAL;
  80
  81         if (atomic_cmpxchg(&gdev->onoff, 0, 1) != 0)
  82                 return -EAGAIN;
  83         if (gdev->state == CCWGROUP_ONLINE)
  84                 goto out;
  85         if (gdrv->set_online)
  86                 ret = gdrv->set_online(gdev);
  87         if (ret)
  88                 goto out;
  89
  90         gdev->state = CCWGROUP_ONLINE;
  91 out:
  92         atomic_set(&gdev->onoff, 0);
  93         return ret;
  94 }
  95 EXPORT_SYMBOL(ccwgroup_set_online);
  96
  97 /**
  98  * ccwgroup_set_offline() - disable a ccwgroup device
  99  * @gdev: target ccwgroup device
 100  *
 101  * This function attempts to put the ccwgroup device into the offline state.
 102  * Returns:
 103  *  %0 on success and a negative error value on failure.
 104  */
 105 int ccwgroup_set_offline(struct ccwgroup_device *gdev)
 106 {
 107         struct ccwgroup_driver *gdrv = to_ccwgroupdrv(gdev->dev.driver);
 108         int ret = -EINVAL;
 109
 110         if (atomic_cmpxchg(&gdev->onoff, 0, 1) != 0)
 111                 return -EAGAIN;
 112         if (gdev->state == CCWGROUP_OFFLINE)
 113                 goto out;
 114         if (gdrv->set_offline)
 115                 ret = gdrv->set_offline(gdev);
 116         if (ret)
 117                 goto out;
 118
 119         gdev->state = CCWGROUP_OFFLINE;
 120 out:
 121         atomic_set(&gdev->onoff, 0);
 122         return ret;
 123 }
 124 EXPORT_SYMBOL(ccwgroup_set_offline);
 125
 126 static ssize_t ccwgroup_online_store(struct device *dev,
 127                                      struct device_attribute *attr,
 128                                      const char *buf, size_t count)
 129 {
 130         struct ccwgroup_device *gdev = to_ccwgroupdev(dev);
 131         unsigned long value;
 132         int ret;
 133
 134         device_lock(dev);
 135         if (!dev->driver) {
 136                 ret = -EINVAL;
 137                 goto out;
 138         }
 139
 140         ret = kstrtoul(buf, 0, &value);
 141         if (ret)
 142                 goto out;
 143
 144         if (value == 1)
 145                 ret = ccwgroup_set_online(gdev);
 146         else if (value == 0)
 147                 ret = ccwgroup_set_offline(gdev);
 148         else
 149                 ret = -EINVAL;
 150 out:
 151         device_unlock(dev);
 152         return (ret == 0) ? count : ret;
 153 }
 154
 155 static ssize_t ccwgroup_online_show(struct device *dev,
 156                                     struct device_attribute *attr,
 157                                     char *buf)
 158 {
 159         struct ccwgroup_device *gdev = to_ccwgroupdev(dev);
 160         int online;
 161
 162         online = (gdev->state == CCWGROUP_ONLINE) ? 1 : 0;
 163
 164         return scnprintf(buf, PAGE_SIZE, "%d\n", online);
 165 }
 166
 167 /*
 168  * Provide an 'ungroup' attribute so the user can remove group devices no
 169  * longer needed or accidentially created. Saves memory :)
 170  */
 171 static void ccwgroup_ungroup(struct ccwgroup_device *gdev)
 172 {
 173         mutex_lock(&gdev->reg_mutex);
 174         if (device_is_registered(&gdev->dev)) {
 175                 __ccwgroup_remove_symlinks(gdev);
 176                 device_unregister(&gdev->dev);
 177                 __ccwgroup_remove_cdev_refs(gdev);
 178         }
 179         mutex_unlock(&gdev->reg_mutex);
 180 }
 181
 182 static ssize_t ccwgroup_ungroup_store(struct device *dev,
 183                                       struct device_attribute *attr,
 184                                       const char *buf, size_t count)
 185 {
 186         struct ccwgroup_device *gdev = to_ccwgroupdev(dev);
 187         int rc = 0;
 188
 189         /* Prevent concurrent online/offline processing and ungrouping. */
 190         if (atomic_cmpxchg(&gdev->onoff, 0, 1) != 0)
 191                 return -EAGAIN;
 192         if (gdev->state != CCWGROUP_OFFLINE) {
 193                 rc = -EINVAL;
 194                 goto out;
 195         }
 196
 197         if (device_remove_file_self(dev, attr))
 198                 ccwgroup_ungroup(gdev);
 199         else
 200                 rc = -ENODEV;
 201 out:
 202         if (rc) {
 203                 /* Release onoff "lock" when ungrouping failed. */
 204                 atomic_set(&gdev->onoff, 0);
 205                 return rc;
 206         }
 207         return count;
 208 }
 209 static DEVICE_ATTR(ungroup, 0200, NULL, ccwgroup_ungroup_store);
 210 static DEVICE_ATTR(online, 0644, ccwgroup_online_show, ccwgroup_online_store);
 211
 212 static struct attribute *ccwgroup_attrs[] = {
 213         &dev_attr_online.attr,
 214         &dev_attr_ungroup.attr,
 215         NULL,
 216 };
 217 static struct attribute_group ccwgroup_attr_group = {
 218         .attrs = ccwgroup_attrs,
 219 };
 220 static const struct attribute_group *ccwgroup_attr_groups[] = {
 221         &ccwgroup_attr_group,
 222         NULL,
 223 };
 224
 225 static void ccwgroup_ungroup_workfn(struct work_struct *work)
 226 {
 227         struct ccwgroup_device *gdev =
 228                 container_of(work, struct ccwgroup_device, ungroup_work);
 229
 230         ccwgroup_ungroup(gdev);
 231         put_device(&gdev->dev);
 232 }
 233
 234 static void ccwgroup_release(struct device *dev)
 235 {
 236         kfree(to_ccwgroupdev(dev));
 237 }
 238
 239 static int __ccwgroup_create_symlinks(struct ccwgroup_device *gdev)
 240 {
 241         char str[8];
 242         int i, rc;
 243
 244         for (i = 0; i < gdev->count; i++) {
 245                 rc = sysfs_create_link(&gdev->cdev[i]->dev.kobj,
 246                                        &gdev->dev.kobj, "group_device");
 247                 if (rc) {
 248                         for (--i; i >= 0; i--)
 249                                 sysfs_remove_link(&gdev->cdev[i]->dev.kobj,
 250                                                   "group_device");
 251                         return rc;
 252                 }
 253         }
 254         for (i = 0; i < gdev->count; i++) {
 255                 sprintf(str, "cdev%d", i);
 256                 rc = sysfs_create_link(&gdev->dev.kobj,
 257                                        &gdev->cdev[i]->dev.kobj, str);
 258                 if (rc) {
 259                         for (--i; i >= 0; i--) {
 260                                 sprintf(str, "cdev%d", i);
 261                                 sysfs_remove_link(&gdev->dev.kobj, str);
 262                         }
 263                         for (i = 0; i < gdev->count; i++)
 264                                 sysfs_remove_link(&gdev->cdev[i]->dev.kobj,
 265                                                   "group_device");
 266                         return rc;
 267                 }
 268         }
 269         return 0;
 270 }
 271
 272 static int __get_next_id(const char **buf, struct ccw_dev_id *id)
 273 {
 274         unsigned int cssid, ssid, devno;
 275         int ret = 0, len;
 276         char *start, *end;
 277
 278         start = (char *)*buf;
 279         end = strchr(start, ',');
 280         if (!end) {
 281                 /* Last entry. Strip trailing newline, if applicable. */
 282                 end = strchr(start, '\n');
 283                 if (end)
 284                         *end = '\0';
 285                 len = strlen(start) + 1;
 286         } else {
 287                 len = end - start + 1;
 288                 end++;
 289         }
 290         if (len <= CCW_BUS_ID_SIZE) {
 291                 if (sscanf(start, "%2x.%1x.%04x", &cssid, &ssid, &devno) != 3)
 292                         ret = -EINVAL;
 293         } else
 294                 ret = -EINVAL;
 295
 296         if (!ret) {
 297                 id->ssid = ssid;
 298                 id->devno = devno;
 299         }
 300         *buf = end;
 301         return ret;
 302 }
 303
 304 /**
 305  * ccwgroup_create_dev() - create and register a ccw group device
 306  * @parent: parent device for the new device
 307  * @gdrv: driver for the new group device
 308  * @num_devices: number of slave devices
 309  * @buf: buffer containing comma separated bus ids of slave devices
 310  *
 311  * Create and register a new ccw group device as a child of @parent. Slave
 312  * devices are obtained from the list of bus ids given in @buf.
 313  * Returns:
 314  *  %0 on success and an error code on failure.
 315  * Context:
 316  *  non-atomic
 317  */
 318 int ccwgroup_create_dev(struct device *parent, struct ccwgroup_driver *gdrv,
 319                         int num_devices, const char *buf)
 320 {
 321         struct ccwgroup_device *gdev;
 322         struct ccw_dev_id dev_id;
 323         int rc, i;
 324
 325         gdev = kzalloc(sizeof(*gdev) + num_devices * sizeof(gdev->cdev[0]),
 326                        GFP_KERNEL);
 327         if (!gdev)
 328                 return -ENOMEM;
 329
 330         atomic_set(&gdev->onoff, 0);
 331         mutex_init(&gdev->reg_mutex);
 332         mutex_lock(&gdev->reg_mutex);
 333         INIT_WORK(&gdev->ungroup_work, ccwgroup_ungroup_workfn);
 334         gdev->count = num_devices;
 335         gdev->dev.bus = &ccwgroup_bus_type;
 336         gdev->dev.parent = parent;
 337         gdev->dev.release = ccwgroup_release;
 338         device_initialize(&gdev->dev);
 339
 340         for (i = 0; i < num_devices && buf; i++) {
 341                 rc = __get_next_id(&buf, &dev_id);
 342                 if (rc != 0)
 343                         goto error;
 344                 gdev->cdev[i] = get_ccwdev_by_dev_id(&dev_id);
 345                 /*
 346                  * All devices have to be of the same type in
 347                  * order to be grouped.
 348                  */
 349                 if (!gdev->cdev[i] || !gdev->cdev[i]->drv ||
 350                     gdev->cdev[i]->drv != gdev->cdev[0]->drv ||
 351                     gdev->cdev[i]->id.driver_info !=
 352                     gdev->cdev[0]->id.driver_info) {
 353                         rc = -EINVAL;
 354                         goto error;
 355                 }
 356                 /* Don't allow a device to belong to more than one group. */
 357                 spin_lock_irq(gdev->cdev[i]->ccwlock);
 358                 if (dev_get_drvdata(&gdev->cdev[i]->dev)) {
 359                         spin_unlock_irq(gdev->cdev[i]->ccwlock);
 360                         rc = -EINVAL;
 361                         goto error;
 362                 }
 363                 dev_set_drvdata(&gdev->cdev[i]->dev, gdev);
 364                 spin_unlock_irq(gdev->cdev[i]->ccwlock);
 365         }
 366         /* Check for sufficient number of bus ids. */
 367         if (i < num_devices) {
 368                 rc = -EINVAL;
 369                 goto error;
 370         }
 371         /* Check for trailing stuff. */
 372         if (i == num_devices && strlen(buf) > 0) {
 373                 rc = -EINVAL;
 374                 goto error;
 375         }
 376
 377         dev_set_name(&gdev->dev, "%s", dev_name(&gdev->cdev[0]->dev));
 378         gdev->dev.groups = ccwgroup_attr_groups;
 379
 380         if (gdrv) {
 381                 gdev->dev.driver = &gdrv->driver;
 382                 rc = gdrv->setup ? gdrv->setup(gdev) : 0;
 383                 if (rc)
 384                         goto error;
 385         }
 386         rc = device_add(&gdev->dev);
 387         if (rc)
 388                 goto error;
 389         rc = __ccwgroup_create_symlinks(gdev);
 390         if (rc) {
 391                 device_del(&gdev->dev);
 392                 goto error;
 393         }
 394         mutex_unlock(&gdev->reg_mutex);
 395         return 0;
 396 error:
 397         for (i = 0; i < num_devices; i++)
 398                 if (gdev->cdev[i]) {
 399                         spin_lock_irq(gdev->cdev[i]->ccwlock);
 400                         if (dev_get_drvdata(&gdev->cdev[i]->dev) == gdev)
 401                                 dev_set_drvdata(&gdev->cdev[i]->dev, NULL);
 402                         spin_unlock_irq(gdev->cdev[i]->ccwlock);
 403                         put_device(&gdev->cdev[i]->dev);
 404                         gdev->cdev[i] = NULL;
 405                 }
 406         mutex_unlock(&gdev->reg_mutex);
 407         put_device(&gdev->dev);
 408         return rc;
 409 }
 410 EXPORT_SYMBOL(ccwgroup_create_dev);
 411
 412 static int ccwgroup_notifier(struct notifier_block *nb, unsigned long action,
 413                              void *data)
 414 {
 415         struct ccwgroup_device *gdev = to_ccwgroupdev(data);
 416
 417         if (action == BUS_NOTIFY_UNBIND_DRIVER) {
 418                 get_device(&gdev->dev);
 419                 schedule_work(&gdev->ungroup_work);
 420         }
 421
 422         return NOTIFY_OK;
 423 }
 424
 425 static struct notifier_block ccwgroup_nb = {
 426         .notifier_call = ccwgroup_notifier
 427 };
 428
 429 static int __init init_ccwgroup(void)
 430 {
 431         int ret;
 432
 433         ret = bus_register(&ccwgroup_bus_type);
 434         if (ret)
 435                 return ret;
 436
 437         ret = bus_register_notifier(&ccwgroup_bus_type, &ccwgroup_nb);
 438         if (ret)
 439                 bus_unregister(&ccwgroup_bus_type);
 440
 441         return ret;
 442 }
 443
 444 static void __exit cleanup_ccwgroup(void)
 445 {
 446         bus_unregister_notifier(&ccwgroup_bus_type, &ccwgroup_nb);
 447         bus_unregister(&ccwgroup_bus_type);
 448 }
 449
 450 module_init(init_ccwgroup);
 451 module_exit(cleanup_ccwgroup);
 452
 453 /************************** driver stuff ******************************/
 454
 455 static int ccwgroup_remove(struct device *dev)
 456 {
 457         struct ccwgroup_device *gdev = to_ccwgroupdev(dev);
 458         struct ccwgroup_driver *gdrv = to_ccwgroupdrv(dev->driver);
 459
 460         if (!dev->driver)
 461                 return 0;
 462         if (gdrv->remove)
 463                 gdrv->remove(gdev);
 464
 465         return 0;
 466 }
 467
 468 static void ccwgroup_shutdown(struct device *dev)
 469 {
 470         struct ccwgroup_device *gdev = to_ccwgroupdev(dev);
 471         struct ccwgroup_driver *gdrv = to_ccwgroupdrv(dev->driver);
 472
 473         if (!dev->driver)
 474                 return;
 475         if (gdrv->shutdown)
 476                 gdrv->shutdown(gdev);
 477 }
 478
 479 static int ccwgroup_pm_prepare(struct device *dev)
 480 {
 481         struct ccwgroup_device *gdev = to_ccwgroupdev(dev);
 482         struct ccwgroup_driver *gdrv = to_ccwgroupdrv(gdev->dev.driver);
 483
 484         /* Fail while device is being set online/offline. */
 485         if (atomic_read(&gdev->onoff))
 486                 return -EAGAIN;
 487
 488         if (!gdev->dev.driver || gdev->state != CCWGROUP_ONLINE)
 489                 return 0;
 490
 491         return gdrv->prepare ? gdrv->prepare(gdev) : 0;
 492 }
 493
 494 static void ccwgroup_pm_complete(struct device *dev)
 495 {
 496         struct ccwgroup_device *gdev = to_ccwgroupdev(dev);
 497         struct ccwgroup_driver *gdrv = to_ccwgroupdrv(dev->driver);
 498
 499         if (!gdev->dev.driver || gdev->state != CCWGROUP_ONLINE)
 500                 return;
 501
 502         if (gdrv->complete)
 503                 gdrv->complete(gdev);
 504 }
 505
 506 static int ccwgroup_pm_freeze(struct device *dev)
 507 {
 508         struct ccwgroup_device *gdev = to_ccwgroupdev(dev);
 509         struct ccwgroup_driver *gdrv = to_ccwgroupdrv(gdev->dev.driver);
 510
 511         if (!gdev->dev.driver || gdev->state != CCWGROUP_ONLINE)
 512                 return 0;
 513
 514         return gdrv->freeze ? gdrv->freeze(gdev) : 0;
 515 }
 516
 517 static int ccwgroup_pm_thaw(struct device *dev)
 518 {
 519         struct ccwgroup_device *gdev = to_ccwgroupdev(dev);
 520         struct ccwgroup_driver *gdrv = to_ccwgroupdrv(gdev->dev.driver);
 521
 522         if (!gdev->dev.driver || gdev->state != CCWGROUP_ONLINE)
 523                 return 0;
 524
 525         return gdrv->thaw ? gdrv->thaw(gdev) : 0;
 526 }
 527
 528 static int ccwgroup_pm_restore(struct device *dev)
 529 {
 530         struct ccwgroup_device *gdev = to_ccwgroupdev(dev);
 531         struct ccwgroup_driver *gdrv = to_ccwgroupdrv(gdev->dev.driver);
 532
 533         if (!gdev->dev.driver || gdev->state != CCWGROUP_ONLINE)
 534                 return 0;
 535
 536         return gdrv->restore ? gdrv->restore(gdev) : 0;
 537 }
 538
 539 static const struct dev_pm_ops ccwgroup_pm_ops = {
 540         .prepare = ccwgroup_pm_prepare,
 541         .complete = ccwgroup_pm_complete,
 542         .freeze = ccwgroup_pm_freeze,
 543         .thaw = ccwgroup_pm_thaw,
 544         .restore = ccwgroup_pm_restore,
 545 };
 546
 547 static struct bus_type ccwgroup_bus_type = {
 548         .name   = "ccwgroup",
 549         .remove = ccwgroup_remove,
 550         .shutdown = ccwgroup_shutdown,
 551         .pm = &ccwgroup_pm_ops,
 552 };
 553
 554 /**
 555  * ccwgroup_driver_register() - register a ccw group driver
 556  * @cdriver: driver to be registered
 557  *
 558  * This function is mainly a wrapper around driver_register().
 559  */
 560 int ccwgroup_driver_register(struct ccwgroup_driver *cdriver)
 561 {
 562         /* register our new driver with the core */
 563         cdriver->driver.bus = &ccwgroup_bus_type;
 564
 565         return driver_register(&cdriver->driver);
 566 }
 567 EXPORT_SYMBOL(ccwgroup_driver_register);
 568
 569 static int __ccwgroup_match_all(struct device *dev, void *data)
 570 {
 571         return 1;
 572 }
 573
 574 /**
 575  * ccwgroup_driver_unregister() - deregister a ccw group driver
 576  * @cdriver: driver to be deregistered
 577  *
 578  * This function is mainly a wrapper around driver_unregister().
 579  */
 580 void ccwgroup_driver_unregister(struct ccwgroup_driver *cdriver)
 581 {
 582         struct device *dev;
 583
 584         /* We don't want ccwgroup devices to live longer than their driver. */
 585         while ((dev = driver_find_device(&cdriver->driver, NULL, NULL,
 586                                          __ccwgroup_match_all))) {
 587                 struct ccwgroup_device *gdev = to_ccwgroupdev(dev);
 588
 589                 ccwgroup_ungroup(gdev);
 590                 put_device(dev);
 591         }
 592         driver_unregister(&cdriver->driver);
 593 }
 594 EXPORT_SYMBOL(ccwgroup_driver_unregister);
 595
 596 /**
 597  * ccwgroup_probe_ccwdev() - probe function for slave devices
 598  * @cdev: ccw device to be probed
 599  *
 600  * This is a dummy probe function for ccw devices that are slave devices in
 601  * a ccw group device.
 602  * Returns:
 603  *  always %0
 604  */
 605 int ccwgroup_probe_ccwdev(struct ccw_device *cdev)
 606 {
 607         return 0;
 608 }
 609 EXPORT_SYMBOL(ccwgroup_probe_ccwdev);
 610
 611 /**
 612  * ccwgroup_remove_ccwdev() - remove function for slave devices
 613  * @cdev: ccw device to be removed
 614  *
 615  * This is a remove function for ccw devices that are slave devices in a ccw
 616  * group device. It sets the ccw device offline and also deregisters the
 617  * embedding ccw group device.
 618  */
 619 void ccwgroup_remove_ccwdev(struct ccw_device *cdev)
 620 {
 621         struct ccwgroup_device *gdev;
 622
 623         /* Ignore offlining errors, device is gone anyway. */
 624         ccw_device_set_offline(cdev);
 625         /* If one of its devices is gone, the whole group is done for. */
 626         spin_lock_irq(cdev->ccwlock);
 627         gdev = dev_get_drvdata(&cdev->dev);
 628         if (!gdev) {
 629                 spin_unlock_irq(cdev->ccwlock);
 630                 return;
 631         }
 632         /* Get ccwgroup device reference for local processing. */
 633         get_device(&gdev->dev);
 634         spin_unlock_irq(cdev->ccwlock);
 635         /* Unregister group device. */
 636         ccwgroup_ungroup(gdev);
 637         /* Release ccwgroup device reference for local processing. */
 638         put_device(&gdev->dev);
 639 }
 640 EXPORT_SYMBOL(ccwgroup_remove_ccwdev);
 641 MODULE_LICENSE("GPL");