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;
 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 out:
 200         if (rc) {
 201                 if (rc != -EAGAIN)
 202                         /* Release onoff "lock" when ungrouping failed. */
 203                         atomic_set(&gdev->onoff, 0);
 204                 return rc;
 205         }
 206         return count;
 207 }
 208 static DEVICE_ATTR(ungroup, 0200, NULL, ccwgroup_ungroup_store);
 209 static DEVICE_ATTR(online, 0644, ccwgroup_online_show, ccwgroup_online_store);
 210
 211 static struct attribute *ccwgroup_attrs[] = {
 212         &dev_attr_online.attr,
 213         &dev_attr_ungroup.attr,
 214         NULL,
 215 };
 216 static struct attribute_group ccwgroup_attr_group = {
 217         .attrs = ccwgroup_attrs,
 218 };
 219 static const struct attribute_group *ccwgroup_attr_groups[] = {
 220         &ccwgroup_attr_group,
 221         NULL,
 222 };
 223
 224 static void ccwgroup_ungroup_workfn(struct work_struct *work)
 225 {
 226         struct ccwgroup_device *gdev =
 227                 container_of(work, struct ccwgroup_device, ungroup_work);
 228
 229         ccwgroup_ungroup(gdev);
 230 }
 231
 232 static void ccwgroup_release(struct device *dev)
 233 {
 234         kfree(to_ccwgroupdev(dev));
 235 }
 236
 237 static int __ccwgroup_create_symlinks(struct ccwgroup_device *gdev)
 238 {
 239         char str[8];
 240         int i, rc;
 241
 242         for (i = 0; i < gdev->count; i++) {
 243                 rc = sysfs_create_link(&gdev->cdev[i]->dev.kobj,
 244                                        &gdev->dev.kobj, "group_device");
 245                 if (rc) {
 246                         for (--i; i >= 0; i--)
 247                                 sysfs_remove_link(&gdev->cdev[i]->dev.kobj,
 248                                                   "group_device");
 249                         return rc;
 250                 }
 251         }
 252         for (i = 0; i < gdev->count; i++) {
 253                 sprintf(str, "cdev%d", i);
 254                 rc = sysfs_create_link(&gdev->dev.kobj,
 255                                        &gdev->cdev[i]->dev.kobj, str);
 256                 if (rc) {
 257                         for (--i; i >= 0; i--) {
 258                                 sprintf(str, "cdev%d", i);
 259                                 sysfs_remove_link(&gdev->dev.kobj, str);
 260                         }
 261                         for (i = 0; i < gdev->count; i++)
 262                                 sysfs_remove_link(&gdev->cdev[i]->dev.kobj,
 263                                                   "group_device");
 264                         return rc;
 265                 }
 266         }
 267         return 0;
 268 }
 269
 270 static int __get_next_id(const char **buf, struct ccw_dev_id *id)
 271 {
 272         unsigned int cssid, ssid, devno;
 273         int ret = 0, len;
 274         char *start, *end;
 275
 276         start = (char *)*buf;
 277         end = strchr(start, ',');
 278         if (!end) {
 279                 /* Last entry. Strip trailing newline, if applicable. */
 280                 end = strchr(start, '\n');
 281                 if (end)
 282                         *end = '\0';
 283                 len = strlen(start) + 1;
 284         } else {
 285                 len = end - start + 1;
 286                 end++;
 287         }
 288         if (len <= CCW_BUS_ID_SIZE) {
 289                 if (sscanf(start, "%2x.%1x.%04x", &cssid, &ssid, &devno) != 3)
 290                         ret = -EINVAL;
 291         } else
 292                 ret = -EINVAL;
 293
 294         if (!ret) {
 295                 id->ssid = ssid;
 296                 id->devno = devno;
 297         }
 298         *buf = end;
 299         return ret;
 300 }
 301
 302 /**
 303  * ccwgroup_create_dev() - create and register a ccw group device
 304  * @parent: parent device for the new device
 305  * @gdrv: driver for the new group device
 306  * @num_devices: number of slave devices
 307  * @buf: buffer containing comma separated bus ids of slave devices
 308  *
 309  * Create and register a new ccw group device as a child of @parent. Slave
 310  * devices are obtained from the list of bus ids given in @buf.
 311  * Returns:
 312  *  %0 on success and an error code on failure.
 313  * Context:
 314  *  non-atomic
 315  */
 316 int ccwgroup_create_dev(struct device *parent, struct ccwgroup_driver *gdrv,
 317                         int num_devices, const char *buf)
 318 {
 319         struct ccwgroup_device *gdev;
 320         struct ccw_dev_id dev_id;
 321         int rc, i;
 322
 323         gdev = kzalloc(sizeof(*gdev) + num_devices * sizeof(gdev->cdev[0]),
 324                        GFP_KERNEL);
 325         if (!gdev)
 326                 return -ENOMEM;
 327
 328         atomic_set(&gdev->onoff, 0);
 329         mutex_init(&gdev->reg_mutex);
 330         mutex_lock(&gdev->reg_mutex);
 331         INIT_WORK(&gdev->ungroup_work, ccwgroup_ungroup_workfn);
 332         gdev->count = num_devices;
 333         gdev->dev.bus = &ccwgroup_bus_type;
 334         gdev->dev.parent = parent;
 335         gdev->dev.release = ccwgroup_release;
 336         device_initialize(&gdev->dev);
 337
 338         for (i = 0; i < num_devices && buf; i++) {
 339                 rc = __get_next_id(&buf, &dev_id);
 340                 if (rc != 0)
 341                         goto error;
 342                 gdev->cdev[i] = get_ccwdev_by_dev_id(&dev_id);
 343                 /*
 344                  * All devices have to be of the same type in
 345                  * order to be grouped.
 346                  */
 347                 if (!gdev->cdev[i] || !gdev->cdev[i]->drv ||
 348                     gdev->cdev[i]->drv != gdev->cdev[0]->drv ||
 349                     gdev->cdev[i]->id.driver_info !=
 350                     gdev->cdev[0]->id.driver_info) {
 351                         rc = -EINVAL;
 352                         goto error;
 353                 }
 354                 /* Don't allow a device to belong to more than one group. */
 355                 spin_lock_irq(gdev->cdev[i]->ccwlock);
 356                 if (dev_get_drvdata(&gdev->cdev[i]->dev)) {
 357                         spin_unlock_irq(gdev->cdev[i]->ccwlock);
 358                         rc = -EINVAL;
 359                         goto error;
 360                 }
 361                 dev_set_drvdata(&gdev->cdev[i]->dev, gdev);
 362                 spin_unlock_irq(gdev->cdev[i]->ccwlock);
 363         }
 364         /* Check for sufficient number of bus ids. */
 365         if (i < num_devices) {
 366                 rc = -EINVAL;
 367                 goto error;
 368         }
 369         /* Check for trailing stuff. */
 370         if (i == num_devices && strlen(buf) > 0) {
 371                 rc = -EINVAL;
 372                 goto error;
 373         }
 374
 375         dev_set_name(&gdev->dev, "%s", dev_name(&gdev->cdev[0]->dev));
 376         gdev->dev.groups = ccwgroup_attr_groups;
 377
 378         if (gdrv) {
 379                 gdev->dev.driver = &gdrv->driver;
 380                 rc = gdrv->setup ? gdrv->setup(gdev) : 0;
 381                 if (rc)
 382                         goto error;
 383         }
 384         rc = device_add(&gdev->dev);
 385         if (rc)
 386                 goto error;
 387         rc = __ccwgroup_create_symlinks(gdev);
 388         if (rc) {
 389                 device_del(&gdev->dev);
 390                 goto error;
 391         }
 392         mutex_unlock(&gdev->reg_mutex);
 393         return 0;
 394 error:
 395         for (i = 0; i < num_devices; i++)
 396                 if (gdev->cdev[i]) {
 397                         spin_lock_irq(gdev->cdev[i]->ccwlock);
 398                         if (dev_get_drvdata(&gdev->cdev[i]->dev) == gdev)
 399                                 dev_set_drvdata(&gdev->cdev[i]->dev, NULL);
 400                         spin_unlock_irq(gdev->cdev[i]->ccwlock);
 401                         put_device(&gdev->cdev[i]->dev);
 402                         gdev->cdev[i] = NULL;
 403                 }
 404         mutex_unlock(&gdev->reg_mutex);
 405         put_device(&gdev->dev);
 406         return rc;
 407 }
 408 EXPORT_SYMBOL(ccwgroup_create_dev);
 409
 410 static int ccwgroup_notifier(struct notifier_block *nb, unsigned long action,
 411                              void *data)
 412 {
 413         struct ccwgroup_device *gdev = to_ccwgroupdev(data);
 414
 415         if (action == BUS_NOTIFY_UNBIND_DRIVER)
 416                 schedule_work(&gdev->ungroup_work);
 417
 418         return NOTIFY_OK;
 419 }
 420
 421 static struct notifier_block ccwgroup_nb = {
 422         .notifier_call = ccwgroup_notifier
 423 };
 424
 425 static int __init init_ccwgroup(void)
 426 {
 427         int ret;
 428
 429         ret = bus_register(&ccwgroup_bus_type);
 430         if (ret)
 431                 return ret;
 432
 433         ret = bus_register_notifier(&ccwgroup_bus_type, &ccwgroup_nb);
 434         if (ret)
 435                 bus_unregister(&ccwgroup_bus_type);
 436
 437         return ret;
 438 }
 439
 440 static void __exit cleanup_ccwgroup(void)
 441 {
 442         bus_unregister_notifier(&ccwgroup_bus_type, &ccwgroup_nb);
 443         bus_unregister(&ccwgroup_bus_type);
 444 }
 445
 446 module_init(init_ccwgroup);
 447 module_exit(cleanup_ccwgroup);
 448
 449 /************************** driver stuff ******************************/
 450
 451 static int ccwgroup_remove(struct device *dev)
 452 {
 453         struct ccwgroup_device *gdev = to_ccwgroupdev(dev);
 454         struct ccwgroup_driver *gdrv = to_ccwgroupdrv(dev->driver);
 455
 456         if (!dev->driver)
 457                 return 0;
 458         if (gdrv->remove)
 459                 gdrv->remove(gdev);
 460
 461         return 0;
 462 }
 463
 464 static void ccwgroup_shutdown(struct device *dev)
 465 {
 466         struct ccwgroup_device *gdev = to_ccwgroupdev(dev);
 467         struct ccwgroup_driver *gdrv = to_ccwgroupdrv(dev->driver);
 468
 469         if (!dev->driver)
 470                 return;
 471         if (gdrv->shutdown)
 472                 gdrv->shutdown(gdev);
 473 }
 474
 475 static int ccwgroup_pm_prepare(struct device *dev)
 476 {
 477         struct ccwgroup_device *gdev = to_ccwgroupdev(dev);
 478         struct ccwgroup_driver *gdrv = to_ccwgroupdrv(gdev->dev.driver);
 479
 480         /* Fail while device is being set online/offline. */
 481         if (atomic_read(&gdev->onoff))
 482                 return -EAGAIN;
 483
 484         if (!gdev->dev.driver || gdev->state != CCWGROUP_ONLINE)
 485                 return 0;
 486
 487         return gdrv->prepare ? gdrv->prepare(gdev) : 0;
 488 }
 489
 490 static void ccwgroup_pm_complete(struct device *dev)
 491 {
 492         struct ccwgroup_device *gdev = to_ccwgroupdev(dev);
 493         struct ccwgroup_driver *gdrv = to_ccwgroupdrv(dev->driver);
 494
 495         if (!gdev->dev.driver || gdev->state != CCWGROUP_ONLINE)
 496                 return;
 497
 498         if (gdrv->complete)
 499                 gdrv->complete(gdev);
 500 }
 501
 502 static int ccwgroup_pm_freeze(struct device *dev)
 503 {
 504         struct ccwgroup_device *gdev = to_ccwgroupdev(dev);
 505         struct ccwgroup_driver *gdrv = to_ccwgroupdrv(gdev->dev.driver);
 506
 507         if (!gdev->dev.driver || gdev->state != CCWGROUP_ONLINE)
 508                 return 0;
 509
 510         return gdrv->freeze ? gdrv->freeze(gdev) : 0;
 511 }
 512
 513 static int ccwgroup_pm_thaw(struct device *dev)
 514 {
 515         struct ccwgroup_device *gdev = to_ccwgroupdev(dev);
 516         struct ccwgroup_driver *gdrv = to_ccwgroupdrv(gdev->dev.driver);
 517
 518         if (!gdev->dev.driver || gdev->state != CCWGROUP_ONLINE)
 519                 return 0;
 520
 521         return gdrv->thaw ? gdrv->thaw(gdev) : 0;
 522 }
 523
 524 static int ccwgroup_pm_restore(struct device *dev)
 525 {
 526         struct ccwgroup_device *gdev = to_ccwgroupdev(dev);
 527         struct ccwgroup_driver *gdrv = to_ccwgroupdrv(gdev->dev.driver);
 528
 529         if (!gdev->dev.driver || gdev->state != CCWGROUP_ONLINE)
 530                 return 0;
 531
 532         return gdrv->restore ? gdrv->restore(gdev) : 0;
 533 }
 534
 535 static const struct dev_pm_ops ccwgroup_pm_ops = {
 536         .prepare = ccwgroup_pm_prepare,
 537         .complete = ccwgroup_pm_complete,
 538         .freeze = ccwgroup_pm_freeze,
 539         .thaw = ccwgroup_pm_thaw,
 540         .restore = ccwgroup_pm_restore,
 541 };
 542
 543 static struct bus_type ccwgroup_bus_type = {
 544         .name   = "ccwgroup",
 545         .remove = ccwgroup_remove,
 546         .shutdown = ccwgroup_shutdown,
 547         .pm = &ccwgroup_pm_ops,
 548 };
 549
 550 /**
 551  * ccwgroup_driver_register() - register a ccw group driver
 552  * @cdriver: driver to be registered
 553  *
 554  * This function is mainly a wrapper around driver_register().
 555  */
 556 int ccwgroup_driver_register(struct ccwgroup_driver *cdriver)
 557 {
 558         /* register our new driver with the core */
 559         cdriver->driver.bus = &ccwgroup_bus_type;
 560
 561         return driver_register(&cdriver->driver);
 562 }
 563 EXPORT_SYMBOL(ccwgroup_driver_register);
 564
 565 static int __ccwgroup_match_all(struct device *dev, void *data)
 566 {
 567         return 1;
 568 }
 569
 570 /**
 571  * ccwgroup_driver_unregister() - deregister a ccw group driver
 572  * @cdriver: driver to be deregistered
 573  *
 574  * This function is mainly a wrapper around driver_unregister().
 575  */
 576 void ccwgroup_driver_unregister(struct ccwgroup_driver *cdriver)
 577 {
 578         struct device *dev;
 579
 580         /* We don't want ccwgroup devices to live longer than their driver. */
 581         while ((dev = driver_find_device(&cdriver->driver, NULL, NULL,
 582                                          __ccwgroup_match_all))) {
 583                 struct ccwgroup_device *gdev = to_ccwgroupdev(dev);
 584
 585                 mutex_lock(&gdev->reg_mutex);
 586                 __ccwgroup_remove_symlinks(gdev);
 587                 device_unregister(dev);
 588                 __ccwgroup_remove_cdev_refs(gdev);
 589                 mutex_unlock(&gdev->reg_mutex);
 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         mutex_lock(&gdev->reg_mutex);
 637         if (device_is_registered(&gdev->dev)) {
 638                 __ccwgroup_remove_symlinks(gdev);
 639                 device_unregister(&gdev->dev);
 640                 __ccwgroup_remove_cdev_refs(gdev);
 641         }
 642         mutex_unlock(&gdev->reg_mutex);
 643         /* Release ccwgroup device reference for local processing. */
 644         put_device(&gdev->dev);
 645 }
 646 EXPORT_SYMBOL(ccwgroup_remove_ccwdev);
 647 MODULE_LICENSE("GPL");