drivers/s390/cio/device.c

   1 /*
   2  *  drivers/s390/cio/device.c
   3  *  bus driver for ccw devices
   4  *
   5  *    Copyright IBM Corp. 2002,2008
   6  *    Author(s): Arnd Bergmann (arndb@de.ibm.com)
   7  *               Cornelia Huck (cornelia.huck@de.ibm.com)
   8  *               Martin Schwidefsky (schwidefsky@de.ibm.com)
   9  */
  10 #include <linux/module.h>
  11 #include <linux/init.h>
  12 #include <linux/spinlock.h>
  13 #include <linux/errno.h>
  14 #include <linux/err.h>
  15 #include <linux/slab.h>
  16 #include <linux/list.h>
  17 #include <linux/device.h>
  18 #include <linux/workqueue.h>
  19 #include <linux/timer.h>
  20
  21 #include <asm/ccwdev.h>
  22 #include <asm/cio.h>
  23 #include <asm/param.h>          /* HZ */
  24 #include <asm/cmb.h>
  25 #include <asm/isc.h>
  26
  27 #include "chp.h"
  28 #include "cio.h"
  29 #include "cio_debug.h"
  30 #include "css.h"
  31 #include "device.h"
  32 #include "ioasm.h"
  33 #include "io_sch.h"
  34 #include "blacklist.h"
  35
  36 static struct timer_list recovery_timer;
  37 static DEFINE_SPINLOCK(recovery_lock);
  38 static int recovery_phase;
  39 static const unsigned long recovery_delay[] = { 3, 30, 300 };
  40
  41 /******************* bus type handling ***********************/
  42
  43 /* The Linux driver model distinguishes between a bus type and
  44  * the bus itself. Of course we only have one channel
  45  * subsystem driver and one channel system per machine, but
  46  * we still use the abstraction. T.R. says it's a good idea. */
  47 static int
  48 ccw_bus_match (struct device * dev, struct device_driver * drv)
  49 {
  50         struct ccw_device *cdev = to_ccwdev(dev);
  51         struct ccw_driver *cdrv = to_ccwdrv(drv);
  52         const struct ccw_device_id *ids = cdrv->ids, *found;
  53
  54         if (!ids)
  55                 return 0;
  56
  57         found = ccw_device_id_match(ids, &cdev->id);
  58         if (!found)
  59                 return 0;
  60
  61         cdev->id.driver_info = found->driver_info;
  62
  63         return 1;
  64 }
  65
  66 /* Store modalias string delimited by prefix/suffix string into buffer with
  67  * specified size. Return length of resulting string (excluding trailing '\0')
  68  * even if string doesn't fit buffer (snprintf semantics). */
  69 static int snprint_alias(char *buf, size_t size,
  70                          struct ccw_device_id *id, const char *suffix)
  71 {
  72         int len;
  73
  74         len = snprintf(buf, size, "ccw:t%04Xm%02X", id->cu_type, id->cu_model);
  75         if (len > size)
  76                 return len;
  77         buf += len;
  78         size -= len;
  79
  80         if (id->dev_type != 0)
  81                 len += snprintf(buf, size, "dt%04Xdm%02X%s", id->dev_type,
  82                                 id->dev_model, suffix);
  83         else
  84                 len += snprintf(buf, size, "dtdm%s", suffix);
  85
  86         return len;
  87 }
  88
  89 /* Set up environment variables for ccw device uevent. Return 0 on success,
  90  * non-zero otherwise. */
  91 static int ccw_uevent(struct device *dev, struct kobj_uevent_env *env)
  92 {
  93         struct ccw_device *cdev = to_ccwdev(dev);
  94         struct ccw_device_id *id = &(cdev->id);
  95         int ret;
  96         char modalias_buf[30];
  97
  98         /* CU_TYPE= */
  99         ret = add_uevent_var(env, "CU_TYPE=%04X", id->cu_type);
 100         if (ret)
 101                 return ret;
 102
 103         /* CU_MODEL= */
 104         ret = add_uevent_var(env, "CU_MODEL=%02X", id->cu_model);
 105         if (ret)
 106                 return ret;
 107
 108         /* The next two can be zero, that's ok for us */
 109         /* DEV_TYPE= */
 110         ret = add_uevent_var(env, "DEV_TYPE=%04X", id->dev_type);
 111         if (ret)
 112                 return ret;
 113
 114         /* DEV_MODEL= */
 115         ret = add_uevent_var(env, "DEV_MODEL=%02X", id->dev_model);
 116         if (ret)
 117                 return ret;
 118
 119         /* MODALIAS=  */
 120         snprint_alias(modalias_buf, sizeof(modalias_buf), id, "");
 121         ret = add_uevent_var(env, "MODALIAS=%s", modalias_buf);
 122         return ret;
 123 }
 124
 125 struct bus_type ccw_bus_type;
 126
 127 static void io_subchannel_irq(struct subchannel *);
 128 static int io_subchannel_probe(struct subchannel *);
 129 static int io_subchannel_remove(struct subchannel *);
 130 static void io_subchannel_shutdown(struct subchannel *);
 131 static int io_subchannel_sch_event(struct subchannel *, int);
 132 static int io_subchannel_chp_event(struct subchannel *, struct chp_link *,
 133                                    int);
 134
 135 static struct css_device_id io_subchannel_ids[] = {
 136         { .match_flags = 0x1, .type = SUBCHANNEL_TYPE_IO, },
 137         { /* end of list */ },
 138 };
 139 MODULE_DEVICE_TABLE(css, io_subchannel_ids);
 140
 141 static struct css_driver io_subchannel_driver = {
 142         .owner = THIS_MODULE,
 143         .subchannel_type = io_subchannel_ids,
 144         .name = "io_subchannel",
 145         .irq = io_subchannel_irq,
 146         .sch_event = io_subchannel_sch_event,
 147         .chp_event = io_subchannel_chp_event,
 148         .probe = io_subchannel_probe,
 149         .remove = io_subchannel_remove,
 150         .shutdown = io_subchannel_shutdown,
 151 };
 152
 153 struct workqueue_struct *ccw_device_work;
 154 wait_queue_head_t ccw_device_init_wq;
 155 atomic_t ccw_device_init_count;
 156
 157 static void recovery_func(unsigned long data);
 158
 159 static int __init
 160 init_ccw_bus_type (void)
 161 {
 162         int ret;
 163
 164         init_waitqueue_head(&ccw_device_init_wq);
 165         atomic_set(&ccw_device_init_count, 0);
 166         setup_timer(&recovery_timer, recovery_func, 0);
 167
 168         ccw_device_work = create_singlethread_workqueue("cio");
 169         if (!ccw_device_work)
 170                 return -ENOMEM; /* FIXME: better errno ? */
 171         slow_path_wq = create_singlethread_workqueue("kslowcrw");
 172         if (!slow_path_wq) {
 173                 ret = -ENOMEM; /* FIXME: better errno ? */
 174                 goto out_err;
 175         }
 176         if ((ret = bus_register (&ccw_bus_type)))
 177                 goto out_err;
 178
 179         ret = css_driver_register(&io_subchannel_driver);
 180         if (ret)
 181                 goto out_err;
 182
 183         wait_event(ccw_device_init_wq,
 184                    atomic_read(&ccw_device_init_count) == 0);
 185         flush_workqueue(ccw_device_work);
 186         return 0;
 187 out_err:
 188         if (ccw_device_work)
 189                 destroy_workqueue(ccw_device_work);
 190         if (slow_path_wq)
 191                 destroy_workqueue(slow_path_wq);
 192         return ret;
 193 }
 194
 195 static void __exit
 196 cleanup_ccw_bus_type (void)
 197 {
 198         css_driver_unregister(&io_subchannel_driver);
 199         bus_unregister(&ccw_bus_type);
 200         destroy_workqueue(ccw_device_work);
 201 }
 202
 203 subsys_initcall(init_ccw_bus_type);
 204 module_exit(cleanup_ccw_bus_type);
 205
 206 /************************ device handling **************************/
 207
 208 /*
 209  * A ccw_device has some interfaces in sysfs in addition to the
 210  * standard ones.
 211  * The following entries are designed to export the information which
 212  * resided in 2.4 in /proc/subchannels. Subchannel and device number
 213  * are obvious, so they don't have an entry :)
 214  * TODO: Split chpids and pimpampom up? Where is "in use" in the tree?
 215  */
 216 static ssize_t
 217 chpids_show (struct device * dev, struct device_attribute *attr, char * buf)
 218 {
 219         struct subchannel *sch = to_subchannel(dev);
 220         struct chsc_ssd_info *ssd = &sch->ssd_info;
 221         ssize_t ret = 0;
 222         int chp;
 223         int mask;
 224
 225         for (chp = 0; chp < 8; chp++) {
 226                 mask = 0x80 >> chp;
 227                 if (ssd->path_mask & mask)
 228                         ret += sprintf(buf + ret, "%02x ", ssd->chpid[chp].id);
 229                 else
 230                         ret += sprintf(buf + ret, "00 ");
 231         }
 232         ret += sprintf (buf+ret, "\n");
 233         return min((ssize_t)PAGE_SIZE, ret);
 234 }
 235
 236 static ssize_t
 237 pimpampom_show (struct device * dev, struct device_attribute *attr, char * buf)
 238 {
 239         struct subchannel *sch = to_subchannel(dev);
 240         struct pmcw *pmcw = &sch->schib.pmcw;
 241
 242         return sprintf (buf, "%02x %02x %02x\n",
 243                         pmcw->pim, pmcw->pam, pmcw->pom);
 244 }
 245
 246 static ssize_t
 247 devtype_show (struct device *dev, struct device_attribute *attr, char *buf)
 248 {
 249         struct ccw_device *cdev = to_ccwdev(dev);
 250         struct ccw_device_id *id = &(cdev->id);
 251
 252         if (id->dev_type != 0)
 253                 return sprintf(buf, "%04x/%02x\n",
 254                                 id->dev_type, id->dev_model);
 255         else
 256                 return sprintf(buf, "n/a\n");
 257 }
 258
 259 static ssize_t
 260 cutype_show (struct device *dev, struct device_attribute *attr, char *buf)
 261 {
 262         struct ccw_device *cdev = to_ccwdev(dev);
 263         struct ccw_device_id *id = &(cdev->id);
 264
 265         return sprintf(buf, "%04x/%02x\n",
 266                        id->cu_type, id->cu_model);
 267 }
 268
 269 static ssize_t
 270 modalias_show (struct device *dev, struct device_attribute *attr, char *buf)
 271 {
 272         struct ccw_device *cdev = to_ccwdev(dev);
 273         struct ccw_device_id *id = &(cdev->id);
 274         int len;
 275
 276         len = snprint_alias(buf, PAGE_SIZE, id, "\n");
 277
 278         return len > PAGE_SIZE ? PAGE_SIZE : len;
 279 }
 280
 281 static ssize_t
 282 online_show (struct device *dev, struct device_attribute *attr, char *buf)
 283 {
 284         struct ccw_device *cdev = to_ccwdev(dev);
 285
 286         return sprintf(buf, cdev->online ? "1\n" : "0\n");
 287 }
 288
 289 int ccw_device_is_orphan(struct ccw_device *cdev)
 290 {
 291         return sch_is_pseudo_sch(to_subchannel(cdev->dev.parent));
 292 }
 293
 294 static void ccw_device_unregister(struct ccw_device *cdev)
 295 {
 296         if (test_and_clear_bit(1, &cdev->private->registered))
 297                 device_del(&cdev->dev);
 298 }
 299
 300 static void ccw_device_remove_orphan_cb(struct work_struct *work)
 301 {
 302         struct ccw_device_private *priv;
 303         struct ccw_device *cdev;
 304
 305         priv = container_of(work, struct ccw_device_private, kick_work);
 306         cdev = priv->cdev;
 307         ccw_device_unregister(cdev);
 308         put_device(&cdev->dev);
 309         /* Release cdev reference for workqueue processing. */
 310         put_device(&cdev->dev);
 311 }
 312
 313 static void ccw_device_call_sch_unregister(struct work_struct *work);
 314
 315 static void
 316 ccw_device_remove_disconnected(struct ccw_device *cdev)
 317 {
 318         unsigned long flags;
 319
 320         /*
 321          * Forced offline in disconnected state means
 322          * 'throw away device'.
 323          */
 324         /* Get cdev reference for workqueue processing. */
 325         if (!get_device(&cdev->dev))
 326                 return;
 327         if (ccw_device_is_orphan(cdev)) {
 328                 /*
 329                  * Deregister ccw device.
 330                  * Unfortunately, we cannot do this directly from the
 331                  * attribute method.
 332                  */
 333                 spin_lock_irqsave(cdev->ccwlock, flags);
 334                 cdev->private->state = DEV_STATE_NOT_OPER;
 335                 spin_unlock_irqrestore(cdev->ccwlock, flags);
 336                 PREPARE_WORK(&cdev->private->kick_work,
 337                                 ccw_device_remove_orphan_cb);
 338         } else
 339                 /* Deregister subchannel, which will kill the ccw device. */
 340                 PREPARE_WORK(&cdev->private->kick_work,
 341                                 ccw_device_call_sch_unregister);
 342         queue_work(slow_path_wq, &cdev->private->kick_work);
 343 }
 344
 345 /**
 346  * ccw_device_set_offline() - disable a ccw device for I/O
 347  * @cdev: target ccw device
 348  *
 349  * This function calls the driver's set_offline() function for @cdev, if
 350  * given, and then disables @cdev.
 351  * Returns:
 352  *   %0 on success and a negative error value on failure.
 353  * Context:
 354  *  enabled, ccw device lock not held
 355  */
 356 int ccw_device_set_offline(struct ccw_device *cdev)
 357 {
 358         int ret;
 359
 360         if (!cdev)
 361                 return -ENODEV;
 362         if (!cdev->online || !cdev->drv)
 363                 return -EINVAL;
 364
 365         if (cdev->drv->set_offline) {
 366                 ret = cdev->drv->set_offline(cdev);
 367                 if (ret != 0)
 368                         return ret;
 369         }
 370         cdev->online = 0;
 371         spin_lock_irq(cdev->ccwlock);
 372         ret = ccw_device_offline(cdev);
 373         if (ret == -ENODEV) {
 374                 if (cdev->private->state != DEV_STATE_NOT_OPER) {
 375                         cdev->private->state = DEV_STATE_OFFLINE;
 376                         dev_fsm_event(cdev, DEV_EVENT_NOTOPER);
 377                 }
 378                 spin_unlock_irq(cdev->ccwlock);
 379                 /* Give up reference from ccw_device_set_online(). */
 380                 put_device(&cdev->dev);
 381                 return ret;
 382         }
 383         spin_unlock_irq(cdev->ccwlock);
 384         if (ret == 0) {
 385                 wait_event(cdev->private->wait_q, dev_fsm_final_state(cdev));
 386                 /* Give up reference from ccw_device_set_online(). */
 387                 put_device(&cdev->dev);
 388         } else {
 389                 CIO_MSG_EVENT(0, "ccw_device_offline returned %d, "
 390                               "device 0.%x.%04x\n",
 391                               ret, cdev->private->dev_id.ssid,
 392                               cdev->private->dev_id.devno);
 393                 cdev->online = 1;
 394         }
 395         return ret;
 396 }
 397
 398 /**
 399  * ccw_device_set_online() - enable a ccw device for I/O
 400  * @cdev: target ccw device
 401  *
 402  * This function first enables @cdev and then calls the driver's set_online()
 403  * function for @cdev, if given. If set_online() returns an error, @cdev is
 404  * disabled again.
 405  * Returns:
 406  *   %0 on success and a negative error value on failure.
 407  * Context:
 408  *  enabled, ccw device lock not held
 409  */
 410 int ccw_device_set_online(struct ccw_device *cdev)
 411 {
 412         int ret;
 413
 414         if (!cdev)
 415                 return -ENODEV;
 416         if (cdev->online || !cdev->drv)
 417                 return -EINVAL;
 418         /* Hold on to an extra reference while device is online. */
 419         if (!get_device(&cdev->dev))
 420                 return -ENODEV;
 421
 422         spin_lock_irq(cdev->ccwlock);
 423         ret = ccw_device_online(cdev);
 424         spin_unlock_irq(cdev->ccwlock);
 425         if (ret == 0)
 426                 wait_event(cdev->private->wait_q, dev_fsm_final_state(cdev));
 427         else {
 428                 CIO_MSG_EVENT(0, "ccw_device_online returned %d, "
 429                               "device 0.%x.%04x\n",
 430                               ret, cdev->private->dev_id.ssid,
 431                               cdev->private->dev_id.devno);
 432                 /* Give up online reference since onlining failed. */
 433                 put_device(&cdev->dev);
 434                 return ret;
 435         }
 436         if (cdev->private->state != DEV_STATE_ONLINE) {
 437                 /* Give up online reference since onlining failed. */
 438                 put_device(&cdev->dev);
 439                 return -ENODEV;
 440         }
 441         if (!cdev->drv->set_online || cdev->drv->set_online(cdev) == 0) {
 442                 cdev->online = 1;
 443                 return 0;
 444         }
 445         spin_lock_irq(cdev->ccwlock);
 446         ret = ccw_device_offline(cdev);
 447         spin_unlock_irq(cdev->ccwlock);
 448         if (ret == 0)
 449                 wait_event(cdev->private->wait_q, dev_fsm_final_state(cdev));
 450         else
 451                 CIO_MSG_EVENT(0, "ccw_device_offline returned %d, "
 452                               "device 0.%x.%04x\n",
 453                               ret, cdev->private->dev_id.ssid,
 454                               cdev->private->dev_id.devno);
 455         /* Give up online reference since onlining failed. */
 456         put_device(&cdev->dev);
 457         return (ret == 0) ? -ENODEV : ret;
 458 }
 459
 460 static void online_store_handle_offline(struct ccw_device *cdev)
 461 {
 462         if (cdev->private->state == DEV_STATE_DISCONNECTED)
 463                 ccw_device_remove_disconnected(cdev);
 464         else if (cdev->drv && cdev->drv->set_offline)
 465                 ccw_device_set_offline(cdev);
 466 }
 467
 468 static int online_store_recog_and_online(struct ccw_device *cdev)
 469 {
 470         int ret;
 471
 472         /* Do device recognition, if needed. */
 473         if (cdev->id.cu_type == 0) {
 474                 ret = ccw_device_recognition(cdev);
 475                 if (ret) {
 476                         CIO_MSG_EVENT(0, "Couldn't start recognition "
 477                                       "for device 0.%x.%04x (ret=%d)\n",
 478                                       cdev->private->dev_id.ssid,
 479                                       cdev->private->dev_id.devno, ret);
 480                         return ret;
 481                 }
 482                 wait_event(cdev->private->wait_q,
 483                            cdev->private->flags.recog_done);
 484         }
 485         if (cdev->drv && cdev->drv->set_online)
 486                 ccw_device_set_online(cdev);
 487         return 0;
 488 }
 489 static int online_store_handle_online(struct ccw_device *cdev, int force)
 490 {
 491         int ret;
 492
 493         ret = online_store_recog_and_online(cdev);
 494         if (ret)
 495                 return ret;
 496         if (force && cdev->private->state == DEV_STATE_BOXED) {
 497                 ret = ccw_device_stlck(cdev);
 498                 if (ret)
 499                         return ret;
 500                 if (cdev->id.cu_type == 0)
 501                         cdev->private->state = DEV_STATE_NOT_OPER;
 502                 online_store_recog_and_online(cdev);
 503         }
 504         return 0;
 505 }
 506
 507 static ssize_t online_store (struct device *dev, struct device_attribute *attr,
 508                              const char *buf, size_t count)
 509 {
 510         struct ccw_device *cdev = to_ccwdev(dev);
 511         int force, ret;
 512         unsigned long i;
 513
 514         if (atomic_cmpxchg(&cdev->private->onoff, 0, 1) != 0)
 515                 return -EAGAIN;
 516
 517         if (cdev->drv && !try_module_get(cdev->drv->owner)) {
 518                 atomic_set(&cdev->private->onoff, 0);
 519                 return -EINVAL;
 520         }
 521         if (!strncmp(buf, "force\n", count)) {
 522                 force = 1;
 523                 i = 1;
 524                 ret = 0;
 525         } else {
 526                 force = 0;
 527                 ret = strict_strtoul(buf, 16, &i);
 528         }
 529         if (ret)
 530                 goto out;
 531         switch (i) {
 532         case 0:
 533                 online_store_handle_offline(cdev);
 534                 ret = count;
 535                 break;
 536         case 1:
 537                 ret = online_store_handle_online(cdev, force);
 538                 if (!ret)
 539                         ret = count;
 540                 break;
 541         default:
 542                 ret = -EINVAL;
 543         }
 544 out:
 545         if (cdev->drv)
 546                 module_put(cdev->drv->owner);
 547         atomic_set(&cdev->private->onoff, 0);
 548         return ret;
 549 }
 550
 551 static ssize_t
 552 available_show (struct device *dev, struct device_attribute *attr, char *buf)
 553 {
 554         struct ccw_device *cdev = to_ccwdev(dev);
 555         struct subchannel *sch;
 556
 557         if (ccw_device_is_orphan(cdev))
 558                 return sprintf(buf, "no device\n");
 559         switch (cdev->private->state) {
 560         case DEV_STATE_BOXED:
 561                 return sprintf(buf, "boxed\n");
 562         case DEV_STATE_DISCONNECTED:
 563         case DEV_STATE_DISCONNECTED_SENSE_ID:
 564         case DEV_STATE_NOT_OPER:
 565                 sch = to_subchannel(dev->parent);
 566                 if (!sch->lpm)
 567                         return sprintf(buf, "no path\n");
 568                 else
 569                         return sprintf(buf, "no device\n");
 570         default:
 571                 /* All other states considered fine. */
 572                 return sprintf(buf, "good\n");
 573         }
 574 }
 575
 576 static DEVICE_ATTR(chpids, 0444, chpids_show, NULL);
 577 static DEVICE_ATTR(pimpampom, 0444, pimpampom_show, NULL);
 578 static DEVICE_ATTR(devtype, 0444, devtype_show, NULL);
 579 static DEVICE_ATTR(cutype, 0444, cutype_show, NULL);
 580 static DEVICE_ATTR(modalias, 0444, modalias_show, NULL);
 581 static DEVICE_ATTR(online, 0644, online_show, online_store);
 582 static DEVICE_ATTR(availability, 0444, available_show, NULL);
 583
 584 static struct attribute *io_subchannel_attrs[] = {
 585         &dev_attr_chpids.attr,
 586         &dev_attr_pimpampom.attr,
 587         NULL,
 588 };
 589
 590 static struct attribute_group io_subchannel_attr_group = {
 591         .attrs = io_subchannel_attrs,
 592 };
 593
 594 static struct attribute * ccwdev_attrs[] = {
 595         &dev_attr_devtype.attr,
 596         &dev_attr_cutype.attr,
 597         &dev_attr_modalias.attr,
 598         &dev_attr_online.attr,
 599         &dev_attr_cmb_enable.attr,
 600         &dev_attr_availability.attr,
 601         NULL,
 602 };
 603
 604 static struct attribute_group ccwdev_attr_group = {
 605         .attrs = ccwdev_attrs,
 606 };
 607
 608 static struct attribute_group *ccwdev_attr_groups[] = {
 609         &ccwdev_attr_group,
 610         NULL,
 611 };
 612
 613 /* this is a simple abstraction for device_register that sets the
 614  * correct bus type and adds the bus specific files */
 615 static int ccw_device_register(struct ccw_device *cdev)
 616 {
 617         struct device *dev = &cdev->dev;
 618         int ret;
 619
 620         dev->bus = &ccw_bus_type;
 621
 622         if ((ret = device_add(dev)))
 623                 return ret;
 624
 625         set_bit(1, &cdev->private->registered);
 626         return ret;
 627 }
 628
 629 struct match_data {
 630         struct ccw_dev_id dev_id;
 631         struct ccw_device * sibling;
 632 };
 633
 634 static int
 635 match_devno(struct device * dev, void * data)
 636 {
 637         struct match_data * d = data;
 638         struct ccw_device * cdev;
 639
 640         cdev = to_ccwdev(dev);
 641         if ((cdev->private->state == DEV_STATE_DISCONNECTED) &&
 642             !ccw_device_is_orphan(cdev) &&
 643             ccw_dev_id_is_equal(&cdev->private->dev_id, &d->dev_id) &&
 644             (cdev != d->sibling))
 645                 return 1;
 646         return 0;
 647 }
 648
 649 static struct ccw_device * get_disc_ccwdev_by_dev_id(struct ccw_dev_id *dev_id,
 650                                                      struct ccw_device *sibling)
 651 {
 652         struct device *dev;
 653         struct match_data data;
 654
 655         data.dev_id = *dev_id;
 656         data.sibling = sibling;
 657         dev = bus_find_device(&ccw_bus_type, NULL, &data, match_devno);
 658
 659         return dev ? to_ccwdev(dev) : NULL;
 660 }
 661
 662 static int match_orphan(struct device *dev, void *data)
 663 {
 664         struct ccw_dev_id *dev_id;
 665         struct ccw_device *cdev;
 666
 667         dev_id = data;
 668         cdev = to_ccwdev(dev);
 669         return ccw_dev_id_is_equal(&cdev->private->dev_id, dev_id);
 670 }
 671
 672 static struct ccw_device *
 673 get_orphaned_ccwdev_by_dev_id(struct channel_subsystem *css,
 674                               struct ccw_dev_id *dev_id)
 675 {
 676         struct device *dev;
 677
 678         dev = device_find_child(&css->pseudo_subchannel->dev, dev_id,
 679                                 match_orphan);
 680
 681         return dev ? to_ccwdev(dev) : NULL;
 682 }
 683
 684 static void
 685 ccw_device_add_changed(struct work_struct *work)
 686 {
 687         struct ccw_device_private *priv;
 688         struct ccw_device *cdev;
 689
 690         priv = container_of(work, struct ccw_device_private, kick_work);
 691         cdev = priv->cdev;
 692         if (device_add(&cdev->dev)) {
 693                 put_device(&cdev->dev);
 694                 return;
 695         }
 696         set_bit(1, &cdev->private->registered);
 697 }
 698
 699 void ccw_device_do_unreg_rereg(struct work_struct *work)
 700 {
 701         struct ccw_device_private *priv;
 702         struct ccw_device *cdev;
 703         struct subchannel *sch;
 704
 705         priv = container_of(work, struct ccw_device_private, kick_work);
 706         cdev = priv->cdev;
 707         sch = to_subchannel(cdev->dev.parent);
 708
 709         ccw_device_unregister(cdev);
 710         PREPARE_WORK(&cdev->private->kick_work,
 711                      ccw_device_add_changed);
 712         queue_work(ccw_device_work, &cdev->private->kick_work);
 713 }
 714
 715 static void
 716 ccw_device_release(struct device *dev)
 717 {
 718         struct ccw_device *cdev;
 719
 720         cdev = to_ccwdev(dev);
 721         /* Release reference of parent subchannel. */
 722         put_device(cdev->dev.parent);
 723         kfree(cdev->private);
 724         kfree(cdev);
 725 }
 726
 727 static struct ccw_device * io_subchannel_allocate_dev(struct subchannel *sch)
 728 {
 729         struct ccw_device *cdev;
 730
 731         cdev  = kzalloc(sizeof(*cdev), GFP_KERNEL);
 732         if (cdev) {
 733                 cdev->private = kzalloc(sizeof(struct ccw_device_private),
 734                                         GFP_KERNEL | GFP_DMA);
 735                 if (cdev->private)
 736                         return cdev;
 737         }
 738         kfree(cdev);
 739         return ERR_PTR(-ENOMEM);
 740 }
 741
 742 static int io_subchannel_initialize_dev(struct subchannel *sch,
 743                                         struct ccw_device *cdev)
 744 {
 745         cdev->private->cdev = cdev;
 746         atomic_set(&cdev->private->onoff, 0);
 747         cdev->dev.parent = &sch->dev;
 748         cdev->dev.release = ccw_device_release;
 749         INIT_WORK(&cdev->private->kick_work, NULL);
 750         cdev->dev.groups = ccwdev_attr_groups;
 751         /* Do first half of device_register. */
 752         device_initialize(&cdev->dev);
 753         if (!get_device(&sch->dev)) {
 754                 /* Release reference from device_initialize(). */
 755                 put_device(&cdev->dev);
 756                 return -ENODEV;
 757         }
 758         return 0;
 759 }
 760
 761 static struct ccw_device * io_subchannel_create_ccwdev(struct subchannel *sch)
 762 {
 763         struct ccw_device *cdev;
 764         int ret;
 765
 766         cdev = io_subchannel_allocate_dev(sch);
 767         if (!IS_ERR(cdev)) {
 768                 ret = io_subchannel_initialize_dev(sch, cdev);
 769                 if (ret) {
 770                         kfree(cdev);
 771                         cdev = ERR_PTR(ret);
 772                 }
 773         }
 774         return cdev;
 775 }
 776
 777 static int io_subchannel_recog(struct ccw_device *, struct subchannel *);
 778
 779 static void sch_attach_device(struct subchannel *sch,
 780                               struct ccw_device *cdev)
 781 {
 782         css_update_ssd_info(sch);
 783         spin_lock_irq(sch->lock);
 784         sch_set_cdev(sch, cdev);
 785         cdev->private->schid = sch->schid;
 786         cdev->ccwlock = sch->lock;
 787         ccw_device_trigger_reprobe(cdev);
 788         spin_unlock_irq(sch->lock);
 789 }
 790
 791 static void sch_attach_disconnected_device(struct subchannel *sch,
 792                                            struct ccw_device *cdev)
 793 {
 794         struct subchannel *other_sch;
 795         int ret;
 796
 797         /* Get reference for new parent. */
 798         if (!get_device(&sch->dev))
 799                 return;
 800         other_sch = to_subchannel(cdev->dev.parent);
 801         /* Note: device_move() changes cdev->dev.parent */
 802         ret = device_move(&cdev->dev, &sch->dev, DPM_ORDER_PARENT_BEFORE_DEV);
 803         if (ret) {
 804                 CIO_MSG_EVENT(0, "Moving disconnected device 0.%x.%04x failed "
 805                               "(ret=%d)!\n", cdev->private->dev_id.ssid,
 806                               cdev->private->dev_id.devno, ret);
 807                 /* Put reference for new parent. */
 808                 put_device(&sch->dev);
 809                 return;
 810         }
 811         sch_set_cdev(other_sch, NULL);
 812         /* No need to keep a subchannel without ccw device around. */
 813         css_sch_device_unregister(other_sch);
 814         sch_attach_device(sch, cdev);
 815         /* Put reference for old parent. */
 816         put_device(&other_sch->dev);
 817 }
 818
 819 static void sch_attach_orphaned_device(struct subchannel *sch,
 820                                        struct ccw_device *cdev)
 821 {
 822         int ret;
 823         struct subchannel *pseudo_sch;
 824
 825         /* Get reference for new parent. */
 826         if (!get_device(&sch->dev))
 827                 return;
 828         pseudo_sch = to_subchannel(cdev->dev.parent);
 829         /*
 830          * Try to move the ccw device to its new subchannel.
 831          * Note: device_move() changes cdev->dev.parent
 832          */
 833         ret = device_move(&cdev->dev, &sch->dev, DPM_ORDER_PARENT_BEFORE_DEV);
 834         if (ret) {
 835                 CIO_MSG_EVENT(0, "Moving device 0.%x.%04x from orphanage "
 836                               "failed (ret=%d)!\n",
 837                               cdev->private->dev_id.ssid,
 838                               cdev->private->dev_id.devno, ret);
 839                 /* Put reference for new parent. */
 840                 put_device(&sch->dev);
 841                 return;
 842         }
 843         sch_attach_device(sch, cdev);
 844         /* Put reference on pseudo subchannel. */
 845         put_device(&pseudo_sch->dev);
 846 }
 847
 848 static void sch_create_and_recog_new_device(struct subchannel *sch)
 849 {
 850         struct ccw_device *cdev;
 851
 852         /* Need to allocate a new ccw device. */
 853         cdev = io_subchannel_create_ccwdev(sch);
 854         if (IS_ERR(cdev)) {
 855                 /* OK, we did everything we could... */
 856                 css_sch_device_unregister(sch);
 857                 return;
 858         }
 859         spin_lock_irq(sch->lock);
 860         sch_set_cdev(sch, cdev);
 861         spin_unlock_irq(sch->lock);
 862         /* Start recognition for the new ccw device. */
 863         if (io_subchannel_recog(cdev, sch)) {
 864                 spin_lock_irq(sch->lock);
 865                 sch_set_cdev(sch, NULL);
 866                 spin_unlock_irq(sch->lock);
 867                 css_sch_device_unregister(sch);
 868                 /* Put reference from io_subchannel_create_ccwdev(). */
 869                 put_device(&sch->dev);
 870                 /* Give up initial reference. */
 871                 put_device(&cdev->dev);
 872         }
 873 }
 874
 875
 876 void ccw_device_move_to_orphanage(struct work_struct *work)
 877 {
 878         struct ccw_device_private *priv;
 879         struct ccw_device *cdev;
 880         struct ccw_device *replacing_cdev;
 881         struct subchannel *sch;
 882         int ret;
 883         struct channel_subsystem *css;
 884         struct ccw_dev_id dev_id;
 885
 886         priv = container_of(work, struct ccw_device_private, kick_work);
 887         cdev = priv->cdev;
 888         sch = to_subchannel(cdev->dev.parent);
 889         css = to_css(sch->dev.parent);
 890         dev_id.devno = sch->schib.pmcw.dev;
 891         dev_id.ssid = sch->schid.ssid;
 892
 893         /* Increase refcount for pseudo subchannel. */
 894         get_device(&css->pseudo_subchannel->dev);
 895         /*
 896          * Move the orphaned ccw device to the orphanage so the replacing
 897          * ccw device can take its place on the subchannel.
 898          * Note: device_move() changes cdev->dev.parent
 899          */
 900         ret = device_move(&cdev->dev, &css->pseudo_subchannel->dev,
 901                 DPM_ORDER_NONE);
 902         if (ret) {
 903                 CIO_MSG_EVENT(0, "Moving device 0.%x.%04x to orphanage failed "
 904                               "(ret=%d)!\n", cdev->private->dev_id.ssid,
 905                               cdev->private->dev_id.devno, ret);
 906                 /* Decrease refcount for pseudo subchannel again. */
 907                 put_device(&css->pseudo_subchannel->dev);
 908                 return;
 909         }
 910         cdev->ccwlock = css->pseudo_subchannel->lock;
 911         /*
 912          * Search for the replacing ccw device
 913          * - among the disconnected devices
 914          * - in the orphanage
 915          */
 916         replacing_cdev = get_disc_ccwdev_by_dev_id(&dev_id, cdev);
 917         if (replacing_cdev) {
 918                 sch_attach_disconnected_device(sch, replacing_cdev);
 919                 /* Release reference from get_disc_ccwdev_by_dev_id() */
 920                 put_device(&replacing_cdev->dev);
 921                 /* Release reference of subchannel from old cdev. */
 922                 put_device(&sch->dev);
 923                 return;
 924         }
 925         replacing_cdev = get_orphaned_ccwdev_by_dev_id(css, &dev_id);
 926         if (replacing_cdev) {
 927                 sch_attach_orphaned_device(sch, replacing_cdev);
 928                 /* Release reference from get_orphaned_ccwdev_by_dev_id() */
 929                 put_device(&replacing_cdev->dev);
 930                 /* Release reference of subchannel from old cdev. */
 931                 put_device(&sch->dev);
 932                 return;
 933         }
 934         sch_create_and_recog_new_device(sch);
 935         /* Release reference of subchannel from old cdev. */
 936         put_device(&sch->dev);
 937 }
 938
 939 /*
 940  * Register recognized device.
 941  */
 942 static void
 943 io_subchannel_register(struct work_struct *work)
 944 {
 945         struct ccw_device_private *priv;
 946         struct ccw_device *cdev;
 947         struct subchannel *sch;
 948         int ret;
 949         unsigned long flags;
 950
 951         priv = container_of(work, struct ccw_device_private, kick_work);
 952         cdev = priv->cdev;
 953         sch = to_subchannel(cdev->dev.parent);
 954         /*
 955          * Check if subchannel is still registered. It may have become
 956          * unregistered if a machine check hit us after finishing
 957          * device recognition but before the register work could be
 958          * queued.
 959          */
 960         if (!device_is_registered(&sch->dev))
 961                 goto out_err;
 962         css_update_ssd_info(sch);
 963         /*
 964          * io_subchannel_register() will also be called after device
 965          * recognition has been done for a boxed device (which will already
 966          * be registered). We need to reprobe since we may now have sense id
 967          * information.
 968          */
 969         if (device_is_registered(&cdev->dev)) {
 970                 if (!cdev->drv) {
 971                         ret = device_reprobe(&cdev->dev);
 972                         if (ret)
 973                                 /* We can't do much here. */
 974                                 CIO_MSG_EVENT(0, "device_reprobe() returned"
 975                                               " %d for 0.%x.%04x\n", ret,
 976                                               cdev->private->dev_id.ssid,
 977                                               cdev->private->dev_id.devno);
 978                 }
 979                 goto out;
 980         }
 981         /*
 982          * Now we know this subchannel will stay, we can throw
 983          * our delayed uevent.
 984          */
 985         dev_set_uevent_suppress(&sch->dev, 0);
 986         kobject_uevent(&sch->dev.kobj, KOBJ_ADD);
 987         /* make it known to the system */
 988         ret = ccw_device_register(cdev);
 989         if (ret) {
 990                 CIO_MSG_EVENT(0, "Could not register ccw dev 0.%x.%04x: %d\n",
 991                               cdev->private->dev_id.ssid,
 992                               cdev->private->dev_id.devno, ret);
 993                 spin_lock_irqsave(sch->lock, flags);
 994                 sch_set_cdev(sch, NULL);
 995                 spin_unlock_irqrestore(sch->lock, flags);
 996                 /* Release initial device reference. */
 997                 put_device(&cdev->dev);
 998                 goto out_err;
 999         }
1000 out:
1001         cdev->private->flags.recog_done = 1;
1002         wake_up(&cdev->private->wait_q);
1003 out_err:
1004         /* Release reference for workqueue processing. */
1005         put_device(&cdev->dev);
1006         if (atomic_dec_and_test(&ccw_device_init_count))
1007                 wake_up(&ccw_device_init_wq);
1008 }
1009
1010 static void ccw_device_call_sch_unregister(struct work_struct *work)
1011 {
1012         struct ccw_device_private *priv;
1013         struct ccw_device *cdev;
1014         struct subchannel *sch;
1015
1016         priv = container_of(work, struct ccw_device_private, kick_work);
1017         cdev = priv->cdev;
1018         /* Get subchannel reference for local processing. */
1019         if (!get_device(cdev->dev.parent))
1020                 return;
1021         sch = to_subchannel(cdev->dev.parent);
1022         css_sch_device_unregister(sch);
1023         /* Reset intparm to zeroes. */
1024         sch->config.intparm = 0;
1025         cio_commit_config(sch);
1026         /* Release cdev reference for workqueue processing.*/
1027         put_device(&cdev->dev);
1028         /* Release subchannel reference for local processing. */
1029         put_device(&sch->dev);
1030 }
1031
1032 /*
1033  * subchannel recognition done. Called from the state machine.
1034  */
1035 void
1036 io_subchannel_recog_done(struct ccw_device *cdev)
1037 {
1038         struct subchannel *sch;
1039
1040         if (css_init_done == 0) {
1041                 cdev->private->flags.recog_done = 1;
1042                 return;
1043         }
1044         switch (cdev->private->state) {
1045         case DEV_STATE_NOT_OPER:
1046                 cdev->private->flags.recog_done = 1;
1047                 /* Remove device found not operational. */
1048                 if (!get_device(&cdev->dev))
1049                         break;
1050                 sch = to_subchannel(cdev->dev.parent);
1051                 PREPARE_WORK(&cdev->private->kick_work,
1052                              ccw_device_call_sch_unregister);
1053                 queue_work(slow_path_wq, &cdev->private->kick_work);
1054                 if (atomic_dec_and_test(&ccw_device_init_count))
1055                         wake_up(&ccw_device_init_wq);
1056                 break;
1057         case DEV_STATE_BOXED:
1058                 /* Device did not respond in time. */
1059         case DEV_STATE_OFFLINE:
1060                 /*
1061                  * We can't register the device in interrupt context so
1062                  * we schedule a work item.
1063                  */
1064                 if (!get_device(&cdev->dev))
1065                         break;
1066                 PREPARE_WORK(&cdev->private->kick_work,
1067                              io_subchannel_register);
1068                 queue_work(slow_path_wq, &cdev->private->kick_work);
1069                 break;
1070         }
1071 }
1072
1073 static int
1074 io_subchannel_recog(struct ccw_device *cdev, struct subchannel *sch)
1075 {
1076         int rc;
1077         struct ccw_device_private *priv;
1078
1079         sch_set_cdev(sch, cdev);
1080         cdev->ccwlock = sch->lock;
1081
1082         /* Init private data. */
1083         priv = cdev->private;
1084         priv->dev_id.devno = sch->schib.pmcw.dev;
1085         priv->dev_id.ssid = sch->schid.ssid;
1086         priv->schid = sch->schid;
1087         priv->state = DEV_STATE_NOT_OPER;
1088         INIT_LIST_HEAD(&priv->cmb_list);
1089         init_waitqueue_head(&priv->wait_q);
1090         init_timer(&priv->timer);
1091
1092         /* Set an initial name for the device. */
1093         if (cio_is_console(sch->schid))
1094                 cdev->dev.init_name = cio_get_console_cdev_name(sch);
1095         else
1096                 dev_set_name(&cdev->dev, "0.%x.%04x",
1097                              sch->schid.ssid, sch->schib.pmcw.dev);
1098
1099         /* Increase counter of devices currently in recognition. */
1100         atomic_inc(&ccw_device_init_count);
1101
1102         /* Start async. device sensing. */
1103         spin_lock_irq(sch->lock);
1104         rc = ccw_device_recognition(cdev);
1105         spin_unlock_irq(sch->lock);
1106         if (rc) {
1107                 if (atomic_dec_and_test(&ccw_device_init_count))
1108                         wake_up(&ccw_device_init_wq);
1109         }
1110         return rc;
1111 }
1112
1113 static void ccw_device_move_to_sch(struct work_struct *work)
1114 {
1115         struct ccw_device_private *priv;
1116         int rc;
1117         struct subchannel *sch;
1118         struct ccw_device *cdev;
1119         struct subchannel *former_parent;
1120
1121         priv = container_of(work, struct ccw_device_private, kick_work);
1122         sch = priv->sch;
1123         cdev = priv->cdev;
1124         former_parent = to_subchannel(cdev->dev.parent);
1125         /* Get reference for new parent. */
1126         if (!get_device(&sch->dev))
1127                 return;
1128         mutex_lock(&sch->reg_mutex);
1129         /*
1130          * Try to move the ccw device to its new subchannel.
1131          * Note: device_move() changes cdev->dev.parent
1132          */
1133         rc = device_move(&cdev->dev, &sch->dev, DPM_ORDER_PARENT_BEFORE_DEV);
1134         mutex_unlock(&sch->reg_mutex);
1135         if (rc) {
1136                 CIO_MSG_EVENT(0, "Moving device 0.%x.%04x to subchannel "
1137                               "0.%x.%04x failed (ret=%d)!\n",
1138                               cdev->private->dev_id.ssid,
1139                               cdev->private->dev_id.devno, sch->schid.ssid,
1140                               sch->schid.sch_no, rc);
1141                 css_sch_device_unregister(sch);
1142                 /* Put reference for new parent again. */
1143                 put_device(&sch->dev);
1144                 goto out;
1145         }
1146         if (!sch_is_pseudo_sch(former_parent)) {
1147                 spin_lock_irq(former_parent->lock);
1148                 sch_set_cdev(former_parent, NULL);
1149                 spin_unlock_irq(former_parent->lock);
1150                 css_sch_device_unregister(former_parent);
1151                 /* Reset intparm to zeroes. */
1152                 former_parent->config.intparm = 0;
1153                 cio_commit_config(former_parent);
1154         }
1155         sch_attach_device(sch, cdev);
1156 out:
1157         /* Put reference for old parent. */
1158         put_device(&former_parent->dev);
1159         put_device(&cdev->dev);
1160 }
1161
1162 static void io_subchannel_irq(struct subchannel *sch)
1163 {
1164         struct ccw_device *cdev;
1165
1166         cdev = sch_get_cdev(sch);
1167
1168         CIO_TRACE_EVENT(3, "IRQ");
1169         CIO_TRACE_EVENT(3, dev_name(&sch->dev));
1170         if (cdev)
1171                 dev_fsm_event(cdev, DEV_EVENT_INTERRUPT);
1172 }
1173
1174 void io_subchannel_init_config(struct subchannel *sch)
1175 {
1176         memset(&sch->config, 0, sizeof(sch->config));
1177         sch->config.csense = 1;
1178         /* Use subchannel mp mode when there is more than 1 installed CHPID. */
1179         if ((sch->schib.pmcw.pim & (sch->schib.pmcw.pim - 1)) != 0)
1180                 sch->config.mp = 1;
1181 }
1182
1183 static void io_subchannel_init_fields(struct subchannel *sch)
1184 {
1185         if (cio_is_console(sch->schid))
1186                 sch->opm = 0xff;
1187         else
1188                 sch->opm = chp_get_sch_opm(sch);
1189         sch->lpm = sch->schib.pmcw.pam & sch->opm;
1190         sch->isc = cio_is_console(sch->schid) ? CONSOLE_ISC : IO_SCH_ISC;
1191
1192         CIO_MSG_EVENT(6, "Detected device %04x on subchannel 0.%x.%04X"
1193                       " - PIM = %02X, PAM = %02X, POM = %02X\n",
1194                       sch->schib.pmcw.dev, sch->schid.ssid,
1195                       sch->schid.sch_no, sch->schib.pmcw.pim,
1196                       sch->schib.pmcw.pam, sch->schib.pmcw.pom);
1197
1198         io_subchannel_init_config(sch);
1199 }
1200
1201 static void io_subchannel_do_unreg(struct work_struct *work)
1202 {
1203         struct subchannel *sch;
1204
1205         sch = container_of(work, struct subchannel, work);
1206         css_sch_device_unregister(sch);
1207         /* Reset intparm to zeroes. */
1208         sch->config.intparm = 0;
1209         cio_commit_config(sch);
1210         put_device(&sch->dev);
1211 }
1212
1213 /* Schedule unregister if we have no cdev. */
1214 static void io_subchannel_schedule_removal(struct subchannel *sch)
1215 {
1216         get_device(&sch->dev);
1217         INIT_WORK(&sch->work, io_subchannel_do_unreg);
1218         queue_work(slow_path_wq, &sch->work);
1219 }
1220
1221 /*
1222  * Note: We always return 0 so that we bind to the device even on error.
1223  * This is needed so that our remove function is called on unregister.
1224  */
1225 static int io_subchannel_probe(struct subchannel *sch)
1226 {
1227         struct ccw_device *cdev;
1228         int rc;
1229         unsigned long flags;
1230         struct ccw_dev_id dev_id;
1231
1232         cdev = sch_get_cdev(sch);
1233         if (cdev) {
1234                 rc = sysfs_create_group(&sch->dev.kobj,
1235                                         &io_subchannel_attr_group);
1236                 if (rc)
1237                         CIO_MSG_EVENT(0, "Failed to create io subchannel "
1238                                       "attributes for subchannel "
1239                                       "0.%x.%04x (rc=%d)\n",
1240                                       sch->schid.ssid, sch->schid.sch_no, rc);
1241                 /*
1242                  * This subchannel already has an associated ccw_device.
1243                  * Throw the delayed uevent for the subchannel, register
1244                  * the ccw_device and exit. This happens for all early
1245                  * devices, e.g. the console.
1246                  */
1247                 dev_set_uevent_suppress(&sch->dev, 0);
1248                 kobject_uevent(&sch->dev.kobj, KOBJ_ADD);
1249                 cdev->dev.groups = ccwdev_attr_groups;
1250                 device_initialize(&cdev->dev);
1251                 ccw_device_register(cdev);
1252                 /*
1253                  * Check if the device is already online. If it is
1254                  * the reference count needs to be corrected since we
1255                  * didn't obtain a reference in ccw_device_set_online.
1256                  */
1257                 if (cdev->private->state != DEV_STATE_NOT_OPER &&
1258                     cdev->private->state != DEV_STATE_OFFLINE &&
1259                     cdev->private->state != DEV_STATE_BOXED)
1260                         get_device(&cdev->dev);
1261                 return 0;
1262         }
1263         io_subchannel_init_fields(sch);
1264         rc = cio_commit_config(sch);
1265         if (rc)
1266                 goto out_schedule;
1267         rc = sysfs_create_group(&sch->dev.kobj,
1268                                 &io_subchannel_attr_group);
1269         if (rc)
1270                 goto out_schedule;
1271         /* Allocate I/O subchannel private data. */
1272         sch->private = kzalloc(sizeof(struct io_subchannel_private),
1273                                GFP_KERNEL | GFP_DMA);
1274         if (!sch->private)
1275                 goto out_err;
1276         /*
1277          * First check if a fitting device may be found amongst the
1278          * disconnected devices or in the orphanage.
1279          */
1280         dev_id.devno = sch->schib.pmcw.dev;
1281         dev_id.ssid = sch->schid.ssid;
1282         cdev = get_disc_ccwdev_by_dev_id(&dev_id, NULL);
1283         if (!cdev)
1284                 cdev = get_orphaned_ccwdev_by_dev_id(to_css(sch->dev.parent),
1285                                                      &dev_id);
1286         if (cdev) {
1287                 /*
1288                  * Schedule moving the device until when we have a registered
1289                  * subchannel to move to and succeed the probe. We can
1290                  * unregister later again, when the probe is through.
1291                  */
1292                 cdev->private->sch = sch;
1293                 PREPARE_WORK(&cdev->private->kick_work,
1294                              ccw_device_move_to_sch);
1295                 queue_work(slow_path_wq, &cdev->private->kick_work);
1296                 return 0;
1297         }
1298         cdev = io_subchannel_create_ccwdev(sch);
1299         if (IS_ERR(cdev))
1300                 goto out_err;
1301         rc = io_subchannel_recog(cdev, sch);
1302         if (rc) {
1303                 spin_lock_irqsave(sch->lock, flags);
1304                 io_subchannel_recog_done(cdev);
1305                 spin_unlock_irqrestore(sch->lock, flags);
1306         }
1307         return 0;
1308 out_err:
1309         kfree(sch->private);
1310         sysfs_remove_group(&sch->dev.kobj, &io_subchannel_attr_group);
1311 out_schedule:
1312         io_subchannel_schedule_removal(sch);
1313         return 0;
1314 }
1315
1316 static int
1317 io_subchannel_remove (struct subchannel *sch)
1318 {
1319         struct ccw_device *cdev;
1320         unsigned long flags;
1321
1322         cdev = sch_get_cdev(sch);
1323         if (!cdev)
1324                 return 0;
1325         /* Set ccw device to not operational and drop reference. */
1326         spin_lock_irqsave(cdev->ccwlock, flags);
1327         sch_set_cdev(sch, NULL);
1328         cdev->private->state = DEV_STATE_NOT_OPER;
1329         spin_unlock_irqrestore(cdev->ccwlock, flags);
1330         ccw_device_unregister(cdev);
1331         put_device(&cdev->dev);
1332         kfree(sch->private);
1333         sysfs_remove_group(&sch->dev.kobj, &io_subchannel_attr_group);
1334         return 0;
1335 }
1336
1337 static int io_subchannel_notify(struct subchannel *sch, int event)
1338 {
1339         struct ccw_device *cdev;
1340
1341         cdev = sch_get_cdev(sch);
1342         if (!cdev)
1343                 return 0;
1344         return ccw_device_notify(cdev, event);
1345 }
1346
1347 static void io_subchannel_verify(struct subchannel *sch)
1348 {
1349         struct ccw_device *cdev;
1350
1351         cdev = sch_get_cdev(sch);
1352         if (cdev)
1353                 dev_fsm_event(cdev, DEV_EVENT_VERIFY);
1354 }
1355
1356 static int check_for_io_on_path(struct subchannel *sch, int mask)
1357 {
1358         if (cio_update_schib(sch))
1359                 return 0;
1360         if (scsw_actl(&sch->schib.scsw) && sch->schib.pmcw.lpum == mask)
1361                 return 1;
1362         return 0;
1363 }
1364
1365 static void terminate_internal_io(struct subchannel *sch,
1366                                   struct ccw_device *cdev)
1367 {
1368         if (cio_clear(sch)) {
1369                 /* Recheck device in case clear failed. */
1370                 sch->lpm = 0;
1371                 if (cdev->online)
1372                         dev_fsm_event(cdev, DEV_EVENT_VERIFY);
1373                 else
1374                         css_schedule_eval(sch->schid);
1375                 return;
1376         }
1377         cdev->private->state = DEV_STATE_CLEAR_VERIFY;
1378         /* Request retry of internal operation. */
1379         cdev->private->flags.intretry = 1;
1380         /* Call handler. */
1381         if (cdev->handler)
1382                 cdev->handler(cdev, cdev->private->intparm,
1383                               ERR_PTR(-EIO));
1384 }
1385
1386 static void io_subchannel_terminate_path(struct subchannel *sch, u8 mask)
1387 {
1388         struct ccw_device *cdev;
1389
1390         cdev = sch_get_cdev(sch);
1391         if (!cdev)
1392                 return;
1393         if (check_for_io_on_path(sch, mask)) {
1394                 if (cdev->private->state == DEV_STATE_ONLINE)
1395                         ccw_device_kill_io(cdev);
1396                 else {
1397                         terminate_internal_io(sch, cdev);
1398                         /* Re-start path verification. */
1399                         dev_fsm_event(cdev, DEV_EVENT_VERIFY);
1400                 }
1401         } else
1402                 /* trigger path verification. */
1403                 dev_fsm_event(cdev, DEV_EVENT_VERIFY);
1404
1405 }
1406
1407 static int io_subchannel_chp_event(struct subchannel *sch,
1408                                    struct chp_link *link, int event)
1409 {
1410         int mask;
1411
1412         mask = chp_ssd_get_mask(&sch->ssd_info, link);
1413         if (!mask)
1414                 return 0;
1415         switch (event) {
1416         case CHP_VARY_OFF:
1417                 sch->opm &= ~mask;
1418                 sch->lpm &= ~mask;
1419                 io_subchannel_terminate_path(sch, mask);
1420                 break;
1421         case CHP_VARY_ON:
1422                 sch->opm |= mask;
1423                 sch->lpm |= mask;
1424                 io_subchannel_verify(sch);
1425                 break;
1426         case CHP_OFFLINE:
1427                 if (cio_update_schib(sch))
1428                         return -ENODEV;
1429                 io_subchannel_terminate_path(sch, mask);
1430                 break;
1431         case CHP_ONLINE:
1432                 if (cio_update_schib(sch))
1433                         return -ENODEV;
1434                 sch->lpm |= mask & sch->opm;
1435                 io_subchannel_verify(sch);
1436                 break;
1437         }
1438         return 0;
1439 }
1440
1441 static void
1442 io_subchannel_shutdown(struct subchannel *sch)
1443 {
1444         struct ccw_device *cdev;
1445         int ret;
1446
1447         cdev = sch_get_cdev(sch);
1448
1449         if (cio_is_console(sch->schid))
1450                 return;
1451         if (!sch->schib.pmcw.ena)
1452                 /* Nothing to do. */
1453                 return;
1454         ret = cio_disable_subchannel(sch);
1455         if (ret != -EBUSY)
1456                 /* Subchannel is disabled, we're done. */
1457                 return;
1458         cdev->private->state = DEV_STATE_QUIESCE;
1459         if (cdev->handler)
1460                 cdev->handler(cdev, cdev->private->intparm,
1461                               ERR_PTR(-EIO));
1462         ret = ccw_device_cancel_halt_clear(cdev);
1463         if (ret == -EBUSY) {
1464                 ccw_device_set_timeout(cdev, HZ/10);
1465                 wait_event(cdev->private->wait_q, dev_fsm_final_state(cdev));
1466         }
1467         cio_disable_subchannel(sch);
1468 }
1469
1470 static int io_subchannel_get_status(struct subchannel *sch)
1471 {
1472         struct schib schib;
1473
1474         if (stsch(sch->schid, &schib) || !schib.pmcw.dnv)
1475                 return CIO_GONE;
1476         if (sch->schib.pmcw.dnv && (schib.pmcw.dev != sch->schib.pmcw.dev))
1477                 return CIO_REVALIDATE;
1478         if (!sch->lpm)
1479                 return CIO_NO_PATH;
1480         return CIO_OPER;
1481 }
1482
1483 static int device_is_disconnected(struct ccw_device *cdev)
1484 {
1485         if (!cdev)
1486                 return 0;
1487         return (cdev->private->state == DEV_STATE_DISCONNECTED ||
1488                 cdev->private->state == DEV_STATE_DISCONNECTED_SENSE_ID);
1489 }
1490
1491 static int recovery_check(struct device *dev, void *data)
1492 {
1493         struct ccw_device *cdev = to_ccwdev(dev);
1494         int *redo = data;
1495
1496         spin_lock_irq(cdev->ccwlock);
1497         switch (cdev->private->state) {
1498         case DEV_STATE_DISCONNECTED:
1499                 CIO_MSG_EVENT(3, "recovery: trigger 0.%x.%04x\n",
1500                               cdev->private->dev_id.ssid,
1501                               cdev->private->dev_id.devno);
1502                 dev_fsm_event(cdev, DEV_EVENT_VERIFY);
1503                 *redo = 1;
1504                 break;
1505         case DEV_STATE_DISCONNECTED_SENSE_ID:
1506                 *redo = 1;
1507                 break;
1508         }
1509         spin_unlock_irq(cdev->ccwlock);
1510
1511         return 0;
1512 }
1513
1514 static void recovery_work_func(struct work_struct *unused)
1515 {
1516         int redo = 0;
1517
1518         bus_for_each_dev(&ccw_bus_type, NULL, &redo, recovery_check);
1519         if (redo) {
1520                 spin_lock_irq(&recovery_lock);
1521                 if (!timer_pending(&recovery_timer)) {
1522                         if (recovery_phase < ARRAY_SIZE(recovery_delay) - 1)
1523                                 recovery_phase++;
1524                         mod_timer(&recovery_timer, jiffies +
1525                                   recovery_delay[recovery_phase] * HZ);
1526                 }
1527                 spin_unlock_irq(&recovery_lock);
1528         } else
1529                 CIO_MSG_EVENT(4, "recovery: end\n");
1530 }
1531
1532 static DECLARE_WORK(recovery_work, recovery_work_func);
1533
1534 static void recovery_func(unsigned long data)
1535 {
1536         /*
1537          * We can't do our recovery in softirq context and it's not
1538          * performance critical, so we schedule it.
1539          */
1540         schedule_work(&recovery_work);
1541 }
1542
1543 static void ccw_device_schedule_recovery(void)
1544 {
1545         unsigned long flags;
1546
1547         CIO_MSG_EVENT(4, "recovery: schedule\n");
1548         spin_lock_irqsave(&recovery_lock, flags);
1549         if (!timer_pending(&recovery_timer) || (recovery_phase != 0)) {
1550                 recovery_phase = 0;
1551                 mod_timer(&recovery_timer, jiffies + recovery_delay[0] * HZ);
1552         }
1553         spin_unlock_irqrestore(&recovery_lock, flags);
1554 }
1555
1556 static int purge_fn(struct device *dev, void *data)
1557 {
1558         struct ccw_device *cdev = to_ccwdev(dev);
1559         struct ccw_device_private *priv = cdev->private;
1560         int unreg;
1561
1562         spin_lock_irq(cdev->ccwlock);
1563         unreg = is_blacklisted(priv->dev_id.ssid, priv->dev_id.devno) &&
1564                 (priv->state == DEV_STATE_OFFLINE);
1565         spin_unlock_irq(cdev->ccwlock);
1566         if (!unreg)
1567                 goto out;
1568         if (!get_device(&cdev->dev))
1569                 goto out;
1570         CIO_MSG_EVENT(3, "ccw: purging 0.%x.%04x\n", priv->dev_id.ssid,
1571                       priv->dev_id.devno);
1572         PREPARE_WORK(&cdev->private->kick_work, ccw_device_call_sch_unregister);
1573         queue_work(slow_path_wq, &cdev->private->kick_work);
1574
1575 out:
1576         /* Abort loop in case of pending signal. */
1577         if (signal_pending(current))
1578                 return -EINTR;
1579
1580         return 0;
1581 }
1582
1583 /**
1584  * ccw_purge_blacklisted - purge unused, blacklisted devices
1585  *
1586  * Unregister all ccw devices that are offline and on the blacklist.
1587  */
1588 int ccw_purge_blacklisted(void)
1589 {
1590         CIO_MSG_EVENT(2, "ccw: purging blacklisted devices\n");
1591         bus_for_each_dev(&ccw_bus_type, NULL, NULL, purge_fn);
1592         return 0;
1593 }
1594
1595 static void device_set_disconnected(struct ccw_device *cdev)
1596 {
1597         if (!cdev)
1598                 return;
1599         ccw_device_set_timeout(cdev, 0);
1600         cdev->private->flags.fake_irb = 0;
1601         cdev->private->state = DEV_STATE_DISCONNECTED;
1602         if (cdev->online)
1603                 ccw_device_schedule_recovery();
1604 }
1605
1606 void ccw_device_set_notoper(struct ccw_device *cdev)
1607 {
1608         struct subchannel *sch = to_subchannel(cdev->dev.parent);
1609
1610         CIO_TRACE_EVENT(2, "notoper");
1611         CIO_TRACE_EVENT(2, dev_name(&sch->dev));
1612         ccw_device_set_timeout(cdev, 0);
1613         cio_disable_subchannel(sch);
1614         cdev->private->state = DEV_STATE_NOT_OPER;
1615 }
1616
1617 static int io_subchannel_sch_event(struct subchannel *sch, int slow)
1618 {
1619         int event, ret, disc;
1620         unsigned long flags;
1621         enum { NONE, UNREGISTER, UNREGISTER_PROBE, REPROBE, DISC } action;
1622         struct ccw_device *cdev;
1623
1624         spin_lock_irqsave(sch->lock, flags);
1625         cdev = sch_get_cdev(sch);
1626         disc = device_is_disconnected(cdev);
1627         if (disc && slow) {
1628                 /* Disconnected devices are evaluated directly only.*/
1629                 spin_unlock_irqrestore(sch->lock, flags);
1630                 return 0;
1631         }
1632         /* No interrupt after machine check - kill pending timers. */
1633         if (cdev)
1634                 ccw_device_set_timeout(cdev, 0);
1635         if (!disc && !slow) {
1636                 /* Non-disconnected devices are evaluated on the slow path. */
1637                 spin_unlock_irqrestore(sch->lock, flags);
1638                 return -EAGAIN;
1639         }
1640         event = io_subchannel_get_status(sch);
1641         CIO_MSG_EVENT(4, "Evaluating schid 0.%x.%04x, event %d, %s, %s path.\n",
1642                       sch->schid.ssid, sch->schid.sch_no, event,
1643                       disc ? "disconnected" : "normal",
1644                       slow ? "slow" : "fast");
1645         /* Analyze subchannel status. */
1646         action = NONE;
1647         switch (event) {
1648         case CIO_NO_PATH:
1649                 if (disc) {
1650                         /* Check if paths have become available. */
1651                         action = REPROBE;
1652                         break;
1653                 }
1654                 /* fall through */
1655         case CIO_GONE:
1656                 /* Ask driver what to do with device. */
1657                 if (io_subchannel_notify(sch, event))
1658                         action = DISC;
1659                 else
1660                         action = UNREGISTER;
1661                 break;
1662         case CIO_REVALIDATE:
1663                 /* Device will be removed, so no notify necessary. */
1664                 if (disc)
1665                         /* Reprobe because immediate unregister might block. */
1666                         action = REPROBE;
1667                 else
1668                         action = UNREGISTER_PROBE;
1669                 break;
1670         case CIO_OPER:
1671                 if (disc)
1672                         /* Get device operational again. */
1673                         action = REPROBE;
1674                 break;
1675         }
1676         /* Perform action. */
1677         ret = 0;
1678         switch (action) {
1679         case UNREGISTER:
1680         case UNREGISTER_PROBE:
1681                 ccw_device_set_notoper(cdev);
1682                 /* Unregister device (will use subchannel lock). */
1683                 spin_unlock_irqrestore(sch->lock, flags);
1684                 css_sch_device_unregister(sch);
1685                 spin_lock_irqsave(sch->lock, flags);
1686
1687                 /* Reset intparm to zeroes. */
1688                 sch->config.intparm = 0;
1689                 cio_commit_config(sch);
1690                 break;
1691         case REPROBE:
1692                 ccw_device_trigger_reprobe(cdev);
1693                 break;
1694         case DISC:
1695                 device_set_disconnected(cdev);
1696                 break;
1697         default:
1698                 break;
1699         }
1700         spin_unlock_irqrestore(sch->lock, flags);
1701         /* Probe if necessary. */
1702         if (action == UNREGISTER_PROBE)
1703                 ret = css_probe_device(sch->schid);
1704
1705         return ret;
1706 }
1707
1708 #ifdef CONFIG_CCW_CONSOLE
1709 static struct ccw_device console_cdev;
1710 static char console_cdev_name[10] = "0.x.xxxx";
1711 static struct ccw_device_private console_private;
1712 static int console_cdev_in_use;
1713
1714 static DEFINE_SPINLOCK(ccw_console_lock);
1715
1716 spinlock_t * cio_get_console_lock(void)
1717 {
1718         return &ccw_console_lock;
1719 }
1720
1721 static int ccw_device_console_enable(struct ccw_device *cdev,
1722                                      struct subchannel *sch)
1723 {
1724         int rc;
1725
1726         /* Attach subchannel private data. */
1727         sch->private = cio_get_console_priv();
1728         memset(sch->private, 0, sizeof(struct io_subchannel_private));
1729         io_subchannel_init_fields(sch);
1730         rc = cio_commit_config(sch);
1731         if (rc)
1732                 return rc;
1733         sch->driver = &io_subchannel_driver;
1734         /* Initialize the ccw_device structure. */
1735         cdev->dev.parent= &sch->dev;
1736         rc = io_subchannel_recog(cdev, sch);
1737         if (rc)
1738                 return rc;
1739
1740         /* Now wait for the async. recognition to come to an end. */
1741         spin_lock_irq(cdev->ccwlock);
1742         while (!dev_fsm_final_state(cdev))
1743                 wait_cons_dev();
1744         rc = -EIO;
1745         if (cdev->private->state != DEV_STATE_OFFLINE)
1746                 goto out_unlock;
1747         ccw_device_online(cdev);
1748         while (!dev_fsm_final_state(cdev))
1749                 wait_cons_dev();
1750         if (cdev->private->state != DEV_STATE_ONLINE)
1751                 goto out_unlock;
1752         rc = 0;
1753 out_unlock:
1754         spin_unlock_irq(cdev->ccwlock);
1755         return 0;
1756 }
1757
1758 struct ccw_device *
1759 ccw_device_probe_console(void)
1760 {
1761         struct subchannel *sch;
1762         int ret;
1763
1764         if (xchg(&console_cdev_in_use, 1) != 0)
1765                 return ERR_PTR(-EBUSY);
1766         sch = cio_probe_console();
1767         if (IS_ERR(sch)) {
1768                 console_cdev_in_use = 0;
1769                 return (void *) sch;
1770         }
1771         memset(&console_cdev, 0, sizeof(struct ccw_device));
1772         memset(&console_private, 0, sizeof(struct ccw_device_private));
1773         console_cdev.private = &console_private;
1774         console_private.cdev = &console_cdev;
1775         ret = ccw_device_console_enable(&console_cdev, sch);
1776         if (ret) {
1777                 cio_release_console();
1778                 console_cdev_in_use = 0;
1779                 return ERR_PTR(ret);
1780         }
1781         console_cdev.online = 1;
1782         return &console_cdev;
1783 }
1784
1785
1786 const char *cio_get_console_cdev_name(struct subchannel *sch)
1787 {
1788         snprintf(console_cdev_name, 10, "0.%x.%04x",
1789                  sch->schid.ssid, sch->schib.pmcw.dev);
1790         return (const char *)console_cdev_name;
1791 }
1792 #endif
1793
1794 /*
1795  * get ccw_device matching the busid, but only if owned by cdrv
1796  */
1797 static int
1798 __ccwdev_check_busid(struct device *dev, void *id)
1799 {
1800         char *bus_id;
1801
1802         bus_id = id;
1803
1804         return (strcmp(bus_id, dev_name(dev)) == 0);
1805 }
1806
1807
1808 /**
1809  * get_ccwdev_by_busid() - obtain device from a bus id
1810  * @cdrv: driver the device is owned by
1811  * @bus_id: bus id of the device to be searched
1812  *
1813  * This function searches all devices owned by @cdrv for a device with a bus
1814  * id matching @bus_id.
1815  * Returns:
1816  *  If a match is found, its reference count of the found device is increased
1817  *  and it is returned; else %NULL is returned.
1818  */
1819 struct ccw_device *get_ccwdev_by_busid(struct ccw_driver *cdrv,
1820                                        const char *bus_id)
1821 {
1822         struct device *dev;
1823         struct device_driver *drv;
1824
1825         drv = get_driver(&cdrv->driver);
1826         if (!drv)
1827                 return NULL;
1828
1829         dev = driver_find_device(drv, NULL, (void *)bus_id,
1830                                  __ccwdev_check_busid);
1831         put_driver(drv);
1832
1833         return dev ? to_ccwdev(dev) : NULL;
1834 }
1835
1836 /************************** device driver handling ************************/
1837
1838 /* This is the implementation of the ccw_driver class. The probe, remove
1839  * and release methods are initially very similar to the device_driver
1840  * implementations, with the difference that they have ccw_device
1841  * arguments.
1842  *
1843  * A ccw driver also contains the information that is needed for
1844  * device matching.
1845  */
1846 static int
1847 ccw_device_probe (struct device *dev)
1848 {
1849         struct ccw_device *cdev = to_ccwdev(dev);
1850         struct ccw_driver *cdrv = to_ccwdrv(dev->driver);
1851         int ret;
1852
1853         cdev->drv = cdrv; /* to let the driver call _set_online */
1854
1855         ret = cdrv->probe ? cdrv->probe(cdev) : -ENODEV;
1856
1857         if (ret) {
1858                 cdev->drv = NULL;
1859                 return ret;
1860         }
1861
1862         return 0;
1863 }
1864
1865 static int
1866 ccw_device_remove (struct device *dev)
1867 {
1868         struct ccw_device *cdev = to_ccwdev(dev);
1869         struct ccw_driver *cdrv = cdev->drv;
1870         int ret;
1871
1872         if (cdrv->remove)
1873                 cdrv->remove(cdev);
1874         if (cdev->online) {
1875                 cdev->online = 0;
1876                 spin_lock_irq(cdev->ccwlock);
1877                 ret = ccw_device_offline(cdev);
1878                 spin_unlock_irq(cdev->ccwlock);
1879                 if (ret == 0)
1880                         wait_event(cdev->private->wait_q,
1881                                    dev_fsm_final_state(cdev));
1882                 else
1883                         CIO_MSG_EVENT(0, "ccw_device_offline returned %d, "
1884                                       "device 0.%x.%04x\n",
1885                                       ret, cdev->private->dev_id.ssid,
1886                                       cdev->private->dev_id.devno);
1887                 /* Give up reference obtained in ccw_device_set_online(). */
1888                 put_device(&cdev->dev);
1889         }
1890         ccw_device_set_timeout(cdev, 0);
1891         cdev->drv = NULL;
1892         return 0;
1893 }
1894
1895 static void ccw_device_shutdown(struct device *dev)
1896 {
1897         struct ccw_device *cdev;
1898
1899         cdev = to_ccwdev(dev);
1900         if (cdev->drv && cdev->drv->shutdown)
1901                 cdev->drv->shutdown(cdev);
1902         disable_cmf(cdev);
1903 }
1904
1905 struct bus_type ccw_bus_type = {
1906         .name   = "ccw",
1907         .match  = ccw_bus_match,
1908         .uevent = ccw_uevent,
1909         .probe  = ccw_device_probe,
1910         .remove = ccw_device_remove,
1911         .shutdown = ccw_device_shutdown,
1912 };
1913
1914 /**
1915  * ccw_driver_register() - register a ccw driver
1916  * @cdriver: driver to be registered
1917  *
1918  * This function is mainly a wrapper around driver_register().
1919  * Returns:
1920  *   %0 on success and a negative error value on failure.
1921  */
1922 int ccw_driver_register(struct ccw_driver *cdriver)
1923 {
1924         struct device_driver *drv = &cdriver->driver;
1925
1926         drv->bus = &ccw_bus_type;
1927         drv->name = cdriver->name;
1928         drv->owner = cdriver->owner;
1929
1930         return driver_register(drv);
1931 }
1932
1933 /**
1934  * ccw_driver_unregister() - deregister a ccw driver
1935  * @cdriver: driver to be deregistered
1936  *
1937  * This function is mainly a wrapper around driver_unregister().
1938  */
1939 void ccw_driver_unregister(struct ccw_driver *cdriver)
1940 {
1941         driver_unregister(&cdriver->driver);
1942 }
1943
1944 /* Helper func for qdio. */
1945 struct subchannel_id
1946 ccw_device_get_subchannel_id(struct ccw_device *cdev)
1947 {
1948         struct subchannel *sch;
1949
1950         sch = to_subchannel(cdev->dev.parent);
1951         return sch->schid;
1952 }
1953
1954 MODULE_LICENSE("GPL");
1955 EXPORT_SYMBOL(ccw_device_set_online);
1956 EXPORT_SYMBOL(ccw_device_set_offline);
1957 EXPORT_SYMBOL(ccw_driver_register);
1958 EXPORT_SYMBOL(ccw_driver_unregister);
1959 EXPORT_SYMBOL(get_ccwdev_by_busid);
1960 EXPORT_SYMBOL(ccw_bus_type);
1961 EXPORT_SYMBOL(ccw_device_work);
1962 EXPORT_SYMBOL_GPL(ccw_device_get_subchannel_id);