drivers/s390/cio/ccwgroup.c

   1 // SPDX-License-Identifier: GPL-2.0
   2 /*
   3  *  bus driver for ccwgroup
   4  *
   5  *  Copyright IBM Corp. 2002, 2012
   6  *
   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/cio.h>
  20 #include <asm/ccwdev.h>
  21 #include <asm/ccwgroup.h>
  22
  23 #include "device.h"
  24
  25 #define CCW_BUS_ID_SIZE         10
  26
  27 /* In Linux 2.4, we had a channel device layer called "chandev"
  28  * that did all sorts of obscure stuff for networking devices.
  29  * This is another driver that serves as a replacement for just
  30  * one of its functions, namely the translation of single subchannels
  31  * to devices that use multiple subchannels.
  32  */
  33
  34 static struct bus_type ccwgroup_bus_type;
  35
  36 static void __ccwgroup_remove_symlinks(struct ccwgroup_device *gdev)
  37 {
  38         int i;
  39         char str[16];
  40
  41         for (i = 0; i < gdev->count; i++) {
  42                 sprintf(str, "cdev%d", i);
  43                 sysfs_remove_link(&gdev->dev.kobj, str);
  44                 sysfs_remove_link(&gdev->cdev[i]->dev.kobj, "group_device");
  45         }
  46 }
  47
  48 /*
  49  * Remove references from ccw devices to ccw group device and from
  50  * ccw group device to ccw devices.
  51  */
  52 static void __ccwgroup_remove_cdev_refs(struct ccwgroup_device *gdev)
  53 {
  54         struct ccw_device *cdev;
  55         int i;
  56
  57         for (i = 0; i < gdev->count; i++) {
  58                 cdev = gdev->cdev[i];
  59                 if (!cdev)
  60                         continue;
  61                 spin_lock_irq(cdev->ccwlock);
  62                 dev_set_drvdata(&cdev->dev, NULL);
  63                 spin_unlock_irq(cdev->ccwlock);
  64                 gdev->cdev[i] = NULL;
  65                 put_device(&cdev->dev);
  66         }
  67 }
  68
  69 /**
  70  * ccwgroup_set_online() - enable a ccwgroup device
  71  * @gdev: target ccwgroup device
  72  *
  73  * This function attempts to put the ccwgroup device into the online state.
  74  * Returns:
  75  *  %0 on success and a negative error value on failure.
  76  */
  77 int ccwgroup_set_online(struct ccwgroup_device *gdev)
  78 {
  79         struct ccwgroup_driver *gdrv = to_ccwgroupdrv(gdev->dev.driver);
  80         int ret = -EINVAL;
  81
  82         if (atomic_cmpxchg(&gdev->onoff, 0, 1) != 0)
  83                 return -EAGAIN;
  84         if (gdev->state == CCWGROUP_ONLINE)
  85                 goto out;
  86         if (gdrv->set_online)
  87                 ret = gdrv->set_online(gdev);
  88         if (ret)
  89                 goto out;
  90
  91         gdev->state = CCWGROUP_ONLINE;
  92 out:
  93         atomic_set(&gdev->onoff, 0);
  94         return ret;
  95 }
  96 EXPORT_SYMBOL(ccwgroup_set_online);
  97
  98 /**
  99  * ccwgroup_set_offline() - disable a ccwgroup device
 100  * @gdev: target ccwgroup device
 101  *
 102  * This function attempts to put the ccwgroup device into the offline state.
 103  * Returns:
 104  *  %0 on success and a negative error value on failure.
 105  */
 106 int ccwgroup_set_offline(struct ccwgroup_device *gdev)
 107 {
 108         struct ccwgroup_driver *gdrv = to_ccwgroupdrv(gdev->dev.driver);
 109         int ret = -EINVAL;
 110
 111         if (atomic_cmpxchg(&gdev->onoff, 0, 1) != 0)
 112                 return -EAGAIN;
 113         if (gdev->state == CCWGROUP_OFFLINE)
 114                 goto out;
 115         if (gdrv->set_offline)
 116                 ret = gdrv->set_offline(gdev);
 117         if (ret)
 118                 goto out;
 119
 120         gdev->state = CCWGROUP_OFFLINE;
 121 out:
 122         atomic_set(&gdev->onoff, 0);
 123         return ret;
 124 }
 125 EXPORT_SYMBOL(ccwgroup_set_offline);
 126
 127 static ssize_t ccwgroup_online_store(struct device *dev,
 128                                      struct device_attribute *attr,
 129                                      const char *buf, size_t count)
 130 {
 131         struct ccwgroup_device *gdev = to_ccwgroupdev(dev);
 132         unsigned long value;
 133         int ret;
 134
 135         device_lock(dev);
 136         if (!dev->driver) {
 137                 ret = -EINVAL;
 138                 goto out;
 139         }
 140
 141         ret = kstrtoul(buf, 0, &value);
 142         if (ret)
 143                 goto out;
 144
 145         if (value == 1)
 146                 ret = ccwgroup_set_online(gdev);
 147         else if (value == 0)
 148                 ret = ccwgroup_set_offline(gdev);
 149         else
 150                 ret = -EINVAL;
 151 out:
 152         device_unlock(dev);
 153         return (ret == 0) ? count : ret;
 154 }
 155
 156 static ssize_t ccwgroup_online_show(struct device *dev,
 157                                     struct device_attribute *attr,
 158                                     char *buf)
 159 {
 160         struct ccwgroup_device *gdev = to_ccwgroupdev(dev);
 161         int online;
 162
 163         online = (gdev->state == CCWGROUP_ONLINE) ? 1 : 0;
 164
 165         return scnprintf(buf, PAGE_SIZE, "%d\n", online);
 166 }
 167
 168 /*
 169  * Provide an 'ungroup' attribute so the user can remove group devices no
 170  * longer needed or accidentially created. Saves memory :)
 171  */
 172 static void ccwgroup_ungroup(struct ccwgroup_device *gdev)
 173 {
 174         mutex_lock(&gdev->reg_mutex);
 175         if (device_is_registered(&gdev->dev)) {
 176                 __ccwgroup_remove_symlinks(gdev);
 177                 device_unregister(&gdev->dev);
 178                 __ccwgroup_remove_cdev_refs(gdev);
 179         }
 180         mutex_unlock(&gdev->reg_mutex);
 181 }
 182
 183 static ssize_t ccwgroup_ungroup_store(struct device *dev,
 184                                       struct device_attribute *attr,
 185                                       const char *buf, size_t count)
 186 {
 187         struct ccwgroup_device *gdev = to_ccwgroupdev(dev);
 188         int rc = 0;
 189
 190         /* Prevent concurrent online/offline processing and ungrouping. */
 191         if (atomic_cmpxchg(&gdev->onoff, 0, 1) != 0)
 192                 return -EAGAIN;
 193         if (gdev->state != CCWGROUP_OFFLINE) {
 194                 rc = -EINVAL;
 195                 goto out;
 196         }
 197
 198         if (device_remove_file_self(dev, attr))
 199                 ccwgroup_ungroup(gdev);
 200         else
 201                 rc = -ENODEV;
 202 out:
 203         if (rc) {
 204                 /* Release onoff "lock" when ungrouping failed. */
 205                 atomic_set(&gdev->onoff, 0);
 206                 return rc;
 207         }
 208         return count;
 209 }
 210 static DEVICE_ATTR(ungroup, 0200, NULL, ccwgroup_ungroup_store);
 211 static DEVICE_ATTR(online, 0644, ccwgroup_online_show, ccwgroup_online_store);
 212
 213 static struct attribute *ccwgroup_attrs[] = {
 214         &dev_attr_online.attr,
 215         &dev_attr_ungroup.attr,
 216         NULL,
 217 };
 218 static struct attribute_group ccwgroup_attr_group = {
 219         .attrs = ccwgroup_attrs,
 220 };
 221 static const struct attribute_group *ccwgroup_attr_groups[] = {
 222         &ccwgroup_attr_group,
 223         NULL,
 224 };
 225
 226 static void ccwgroup_ungroup_workfn(struct work_struct *work)
 227 {
 228         struct ccwgroup_device *gdev =
 229                 container_of(work, struct ccwgroup_device, ungroup_work);
 230
 231         ccwgroup_ungroup(gdev);
 232         put_device(&gdev->dev);
 233 }
 234
 235 static void ccwgroup_release(struct device *dev)
 236 {
 237         kfree(to_ccwgroupdev(dev));
 238 }
 239
 240 static int __ccwgroup_create_symlinks(struct ccwgroup_device *gdev)
 241 {
 242         char str[16];
 243         int i, rc;
 244
 245         for (i = 0; i < gdev->count; i++) {
 246                 rc = sysfs_create_link(&gdev->cdev[i]->dev.kobj,
 247                                        &gdev->dev.kobj, "group_device");
 248                 if (rc) {
 249                         for (--i; i >= 0; i--)
 250                                 sysfs_remove_link(&gdev->cdev[i]->dev.kobj,
 251                                                   "group_device");
 252                         return rc;
 253                 }
 254         }
 255         for (i = 0; i < gdev->count; i++) {
 256                 sprintf(str, "cdev%d", i);
 257                 rc = sysfs_create_link(&gdev->dev.kobj,
 258                                        &gdev->cdev[i]->dev.kobj, str);
 259                 if (rc) {
 260                         for (--i; i >= 0; i--) {
 261                                 sprintf(str, "cdev%d", i);
 262                                 sysfs_remove_link(&gdev->dev.kobj, str);
 263                         }
 264                         for (i = 0; i < gdev->count; i++)
 265                                 sysfs_remove_link(&gdev->cdev[i]->dev.kobj,
 266                                                   "group_device");
 267                         return rc;
 268                 }
 269         }
 270         return 0;
 271 }
 272
 273 static int __get_next_id(const char **buf, struct ccw_dev_id *id)
 274 {
 275         unsigned int cssid, ssid, devno;
 276         int ret = 0, len;
 277         char *start, *end;
 278
 279         start = (char *)*buf;
 280         end = strchr(start, ',');
 281         if (!end) {
 282                 /* Last entry. Strip trailing newline, if applicable. */
 283                 end = strchr(start, '\n');
 284                 if (end)
 285                         *end = '\0';
 286                 len = strlen(start) + 1;
 287         } else {
 288                 len = end - start + 1;
 289                 end++;
 290         }
 291         if (len <= CCW_BUS_ID_SIZE) {
 292                 if (sscanf(start, "%2x.%1x.%04x", &cssid, &ssid, &devno) != 3)
 293                         ret = -EINVAL;
 294         } else
 295                 ret = -EINVAL;
 296
 297         if (!ret) {
 298                 id->ssid = ssid;
 299                 id->devno = devno;
 300         }
 301         *buf = end;
 302         return ret;
 303 }
 304
 305 /**
 306  * ccwgroup_create_dev() - create and register a ccw group device
 307  * @parent: parent device for the new device
 308  * @gdrv: driver for the new group device
 309  * @num_devices: number of slave devices
 310  * @buf: buffer containing comma separated bus ids of slave devices
 311  *
 312  * Create and register a new ccw group device as a child of @parent. Slave
 313  * devices are obtained from the list of bus ids given in @buf.
 314  * Returns:
 315  *  %0 on success and an error code on failure.
 316  * Context:
 317  *  non-atomic
 318  */
 319 int ccwgroup_create_dev(struct device *parent, struct ccwgroup_driver *gdrv,
 320                         int num_devices, const char *buf)
 321 {
 322         struct ccwgroup_device *gdev;
 323         struct ccw_dev_id dev_id;
 324         int rc, i;
 325
 326         gdev = kzalloc(sizeof(*gdev) + num_devices * sizeof(gdev->cdev[0]),
 327                        GFP_KERNEL);
 328         if (!gdev)
 329                 return -ENOMEM;
 330
 331         atomic_set(&gdev->onoff, 0);
 332         mutex_init(&gdev->reg_mutex);
 333         mutex_lock(&gdev->reg_mutex);
 334         INIT_WORK(&gdev->ungroup_work, ccwgroup_ungroup_workfn);
 335         gdev->count = num_devices;
 336         gdev->dev.bus = &ccwgroup_bus_type;
 337         gdev->dev.parent = parent;
 338         gdev->dev.release = ccwgroup_release;
 339         device_initialize(&gdev->dev);
 340
 341         for (i = 0; i < num_devices && buf; i++) {
 342                 rc = __get_next_id(&buf, &dev_id);
 343                 if (rc != 0)
 344                         goto error;
 345                 gdev->cdev[i] = get_ccwdev_by_dev_id(&dev_id);
 346                 /*
 347                  * All devices have to be of the same type in
 348                  * order to be grouped.
 349                  */
 350                 if (!gdev->cdev[i] || !gdev->cdev[i]->drv ||
 351                     gdev->cdev[i]->drv != gdev->cdev[0]->drv ||
 352                     gdev->cdev[i]->id.driver_info !=
 353                     gdev->cdev[0]->id.driver_info) {
 354                         rc = -EINVAL;
 355                         goto error;
 356                 }
 357                 /* Don't allow a device to belong to more than one group. */
 358                 spin_lock_irq(gdev->cdev[i]->ccwlock);
 359                 if (dev_get_drvdata(&gdev->cdev[i]->dev)) {
 360                         spin_unlock_irq(gdev->cdev[i]->ccwlock);
 361                         rc = -EINVAL;
 362                         goto error;
 363                 }
 364                 dev_set_drvdata(&gdev->cdev[i]->dev, gdev);
 365                 spin_unlock_irq(gdev->cdev[i]->ccwlock);
 366         }
 367         /* Check for sufficient number of bus ids. */
 368         if (i < num_devices) {
 369                 rc = -EINVAL;
 370                 goto error;
 371         }
 372         /* Check for trailing stuff. */
 373         if (i == num_devices && strlen(buf) > 0) {
 374                 rc = -EINVAL;
 375                 goto error;
 376         }
 377         /* Check if the devices are bound to the required ccw driver. */
 378         if (gdev->count && gdrv && gdrv->ccw_driver &&
 379             gdev->cdev[0]->drv != gdrv->ccw_driver) {
 380                 rc = -EINVAL;
 381                 goto error;
 382         }
 383
 384         dev_set_name(&gdev->dev, "%s", dev_name(&gdev->cdev[0]->dev));
 385         gdev->dev.groups = ccwgroup_attr_groups;
 386
 387         if (gdrv) {
 388                 gdev->dev.driver = &gdrv->driver;
 389                 rc = gdrv->setup ? gdrv->setup(gdev) : 0;
 390                 if (rc)
 391                         goto error;
 392         }
 393         rc = device_add(&gdev->dev);
 394         if (rc)
 395                 goto error;
 396         rc = __ccwgroup_create_symlinks(gdev);
 397         if (rc) {
 398                 device_del(&gdev->dev);
 399                 goto error;
 400         }
 401         mutex_unlock(&gdev->reg_mutex);
 402         return 0;
 403 error:
 404         for (i = 0; i < num_devices; i++)
 405                 if (gdev->cdev[i]) {
 406                         spin_lock_irq(gdev->cdev[i]->ccwlock);
 407                         if (dev_get_drvdata(&gdev->cdev[i]->dev) == gdev)
 408                                 dev_set_drvdata(&gdev->cdev[i]->dev, NULL);
 409                         spin_unlock_irq(gdev->cdev[i]->ccwlock);
 410                         put_device(&gdev->cdev[i]->dev);
 411                         gdev->cdev[i] = NULL;
 412                 }
 413         mutex_unlock(&gdev->reg_mutex);
 414         put_device(&gdev->dev);
 415         return rc;
 416 }
 417 EXPORT_SYMBOL(ccwgroup_create_dev);
 418
 419 static int ccwgroup_notifier(struct notifier_block *nb, unsigned long action,
 420                              void *data)
 421 {
 422         struct ccwgroup_device *gdev = to_ccwgroupdev(data);
 423
 424         if (action == BUS_NOTIFY_UNBIND_DRIVER) {
 425                 get_device(&gdev->dev);
 426                 schedule_work(&gdev->ungroup_work);
 427         }
 428
 429         return NOTIFY_OK;
 430 }
 431
 432 static struct notifier_block ccwgroup_nb = {
 433         .notifier_call = ccwgroup_notifier
 434 };
 435
 436 static int __init init_ccwgroup(void)
 437 {
 438         int ret;
 439
 440         ret = bus_register(&ccwgroup_bus_type);
 441         if (ret)
 442                 return ret;
 443
 444         ret = bus_register_notifier(&ccwgroup_bus_type, &ccwgroup_nb);
 445         if (ret)
 446                 bus_unregister(&ccwgroup_bus_type);
 447
 448         return ret;
 449 }
 450
 451 static void __exit cleanup_ccwgroup(void)
 452 {
 453         bus_unregister_notifier(&ccwgroup_bus_type, &ccwgroup_nb);
 454         bus_unregister(&ccwgroup_bus_type);
 455 }
 456
 457 module_init(init_ccwgroup);
 458 module_exit(cleanup_ccwgroup);
 459
 460 /************************** driver stuff ******************************/
 461
 462 static int ccwgroup_remove(struct device *dev)
 463 {
 464         struct ccwgroup_device *gdev = to_ccwgroupdev(dev);
 465         struct ccwgroup_driver *gdrv = to_ccwgroupdrv(dev->driver);
 466
 467         if (!dev->driver)
 468                 return 0;
 469         if (gdrv->remove)
 470                 gdrv->remove(gdev);
 471
 472         return 0;
 473 }
 474
 475 static void ccwgroup_shutdown(struct device *dev)
 476 {
 477         struct ccwgroup_device *gdev = to_ccwgroupdev(dev);
 478         struct ccwgroup_driver *gdrv = to_ccwgroupdrv(dev->driver);
 479
 480         if (!dev->driver)
 481                 return;
 482         if (gdrv->shutdown)
 483                 gdrv->shutdown(gdev);
 484 }
 485
 486 static int ccwgroup_pm_prepare(struct device *dev)
 487 {
 488         struct ccwgroup_device *gdev = to_ccwgroupdev(dev);
 489         struct ccwgroup_driver *gdrv = to_ccwgroupdrv(gdev->dev.driver);
 490
 491         /* Fail while device is being set online/offline. */
 492         if (atomic_read(&gdev->onoff))
 493                 return -EAGAIN;
 494
 495         if (!gdev->dev.driver || gdev->state != CCWGROUP_ONLINE)
 496                 return 0;
 497
 498         return gdrv->prepare ? gdrv->prepare(gdev) : 0;
 499 }
 500
 501 static void ccwgroup_pm_complete(struct device *dev)
 502 {
 503         struct ccwgroup_device *gdev = to_ccwgroupdev(dev);
 504         struct ccwgroup_driver *gdrv = to_ccwgroupdrv(dev->driver);
 505
 506         if (!gdev->dev.driver || gdev->state != CCWGROUP_ONLINE)
 507                 return;
 508
 509         if (gdrv->complete)
 510                 gdrv->complete(gdev);
 511 }
 512
 513 static int ccwgroup_pm_freeze(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->freeze ? gdrv->freeze(gdev) : 0;
 522 }
 523
 524 static int ccwgroup_pm_thaw(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->thaw ? gdrv->thaw(gdev) : 0;
 533 }
 534
 535 static int ccwgroup_pm_restore(struct device *dev)
 536 {
 537         struct ccwgroup_device *gdev = to_ccwgroupdev(dev);
 538         struct ccwgroup_driver *gdrv = to_ccwgroupdrv(gdev->dev.driver);
 539
 540         if (!gdev->dev.driver || gdev->state != CCWGROUP_ONLINE)
 541                 return 0;
 542
 543         return gdrv->restore ? gdrv->restore(gdev) : 0;
 544 }
 545
 546 static const struct dev_pm_ops ccwgroup_pm_ops = {
 547         .prepare = ccwgroup_pm_prepare,
 548         .complete = ccwgroup_pm_complete,
 549         .freeze = ccwgroup_pm_freeze,
 550         .thaw = ccwgroup_pm_thaw,
 551         .restore = ccwgroup_pm_restore,
 552 };
 553
 554 static struct bus_type ccwgroup_bus_type = {
 555         .name   = "ccwgroup",
 556         .remove = ccwgroup_remove,
 557         .shutdown = ccwgroup_shutdown,
 558         .pm = &ccwgroup_pm_ops,
 559 };
 560
 561 /**
 562  * ccwgroup_driver_register() - register a ccw group driver
 563  * @cdriver: driver to be registered
 564  *
 565  * This function is mainly a wrapper around driver_register().
 566  */
 567 int ccwgroup_driver_register(struct ccwgroup_driver *cdriver)
 568 {
 569         /* register our new driver with the core */
 570         cdriver->driver.bus = &ccwgroup_bus_type;
 571
 572         return driver_register(&cdriver->driver);
 573 }
 574 EXPORT_SYMBOL(ccwgroup_driver_register);
 575
 576 static int __ccwgroup_match_all(struct device *dev, void *data)
 577 {
 578         return 1;
 579 }
 580
 581 /**
 582  * ccwgroup_driver_unregister() - deregister a ccw group driver
 583  * @cdriver: driver to be deregistered
 584  *
 585  * This function is mainly a wrapper around driver_unregister().
 586  */
 587 void ccwgroup_driver_unregister(struct ccwgroup_driver *cdriver)
 588 {
 589         struct device *dev;
 590
 591         /* We don't want ccwgroup devices to live longer than their driver. */
 592         while ((dev = driver_find_device(&cdriver->driver, NULL, NULL,
 593                                          __ccwgroup_match_all))) {
 594                 struct ccwgroup_device *gdev = to_ccwgroupdev(dev);
 595
 596                 ccwgroup_ungroup(gdev);
 597                 put_device(dev);
 598         }
 599         driver_unregister(&cdriver->driver);
 600 }
 601 EXPORT_SYMBOL(ccwgroup_driver_unregister);
 602
 603 /**
 604  * ccwgroup_probe_ccwdev() - probe function for slave devices
 605  * @cdev: ccw device to be probed
 606  *
 607  * This is a dummy probe function for ccw devices that are slave devices in
 608  * a ccw group device.
 609  * Returns:
 610  *  always %0
 611  */
 612 int ccwgroup_probe_ccwdev(struct ccw_device *cdev)
 613 {
 614         return 0;
 615 }
 616 EXPORT_SYMBOL(ccwgroup_probe_ccwdev);
 617
 618 /**
 619  * ccwgroup_remove_ccwdev() - remove function for slave devices
 620  * @cdev: ccw device to be removed
 621  *
 622  * This is a remove function for ccw devices that are slave devices in a ccw
 623  * group device. It sets the ccw device offline and also deregisters the
 624  * embedding ccw group device.
 625  */
 626 void ccwgroup_remove_ccwdev(struct ccw_device *cdev)
 627 {
 628         struct ccwgroup_device *gdev;
 629
 630         /* Ignore offlining errors, device is gone anyway. */
 631         ccw_device_set_offline(cdev);
 632         /* If one of its devices is gone, the whole group is done for. */
 633         spin_lock_irq(cdev->ccwlock);
 634         gdev = dev_get_drvdata(&cdev->dev);
 635         if (!gdev) {
 636                 spin_unlock_irq(cdev->ccwlock);
 637                 return;
 638         }
 639         /* Get ccwgroup device reference for local processing. */
 640         get_device(&gdev->dev);
 641         spin_unlock_irq(cdev->ccwlock);
 642         /* Unregister group device. */
 643         ccwgroup_ungroup(gdev);
 644         /* Release ccwgroup device reference for local processing. */
 645         put_device(&gdev->dev);
 646 }
 647 EXPORT_SYMBOL(ccwgroup_remove_ccwdev);
 648 MODULE_LICENSE("GPL");