drivers/s390/cio/device.c

   1 // SPDX-License-Identifier: GPL-1.0+
   2 /*
   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
  11 #define KMSG_COMPONENT "cio"
  12 #define pr_fmt(fmt) KMSG_COMPONENT ": " fmt
  13
  14 #include <linux/export.h>
  15 #include <linux/init.h>
  16 #include <linux/spinlock.h>
  17 #include <linux/errno.h>
  18 #include <linux/err.h>
  19 #include <linux/slab.h>
  20 #include <linux/list.h>
  21 #include <linux/device.h>
  22 #include <linux/workqueue.h>
  23 #include <linux/delay.h>
  24 #include <linux/timer.h>
  25 #include <linux/kernel_stat.h>
  26 #include <linux/sched/signal.h>
  27 #include <linux/dma-mapping.h>
  28
  29 #include <asm/ccwdev.h>
  30 #include <asm/cio.h>
  31 #include <asm/param.h>          /* HZ */
  32 #include <asm/cmb.h>
  33 #include <asm/isc.h>
  34
  35 #include "chp.h"
  36 #include "cio.h"
  37 #include "cio_debug.h"
  38 #include "css.h"
  39 #include "device.h"
  40 #include "ioasm.h"
  41 #include "io_sch.h"
  42 #include "blacklist.h"
  43 #include "chsc.h"
  44
  45 static struct timer_list recovery_timer;
  46 static DEFINE_SPINLOCK(recovery_lock);
  47 static int recovery_phase;
  48 static const unsigned long recovery_delay[] = { 3, 30, 300 };
  49
  50 static atomic_t ccw_device_init_count = ATOMIC_INIT(0);
  51 static DECLARE_WAIT_QUEUE_HEAD(ccw_device_init_wq);
  52 static struct bus_type ccw_bus_type;
  53
  54 /******************* bus type handling ***********************/
  55
  56 /* The Linux driver model distinguishes between a bus type and
  57  * the bus itself. Of course we only have one channel
  58  * subsystem driver and one channel system per machine, but
  59  * we still use the abstraction. T.R. says it's a good idea. */
  60 static int
  61 ccw_bus_match (struct device * dev, struct device_driver * drv)
  62 {
  63         struct ccw_device *cdev = to_ccwdev(dev);
  64         struct ccw_driver *cdrv = to_ccwdrv(drv);
  65         const struct ccw_device_id *ids = cdrv->ids, *found;
  66
  67         if (!ids)
  68                 return 0;
  69
  70         found = ccw_device_id_match(ids, &cdev->id);
  71         if (!found)
  72                 return 0;
  73
  74         cdev->id.driver_info = found->driver_info;
  75
  76         return 1;
  77 }
  78
  79 /* Store modalias string delimited by prefix/suffix string into buffer with
  80  * specified size. Return length of resulting string (excluding trailing '\0')
  81  * even if string doesn't fit buffer (snprintf semantics). */
  82 static int snprint_alias(char *buf, size_t size,
  83                          struct ccw_device_id *id, const char *suffix)
  84 {
  85         int len;
  86
  87         len = snprintf(buf, size, "ccw:t%04Xm%02X", id->cu_type, id->cu_model);
  88         if (len > size)
  89                 return len;
  90         buf += len;
  91         size -= len;
  92
  93         if (id->dev_type != 0)
  94                 len += snprintf(buf, size, "dt%04Xdm%02X%s", id->dev_type,
  95                                 id->dev_model, suffix);
  96         else
  97                 len += snprintf(buf, size, "dtdm%s", suffix);
  98
  99         return len;
 100 }
 101
 102 /* Set up environment variables for ccw device uevent. Return 0 on success,
 103  * non-zero otherwise. */
 104 static int ccw_uevent(struct device *dev, struct kobj_uevent_env *env)
 105 {
 106         struct ccw_device *cdev = to_ccwdev(dev);
 107         struct ccw_device_id *id = &(cdev->id);
 108         int ret;
 109         char modalias_buf[30];
 110
 111         /* CU_TYPE= */
 112         ret = add_uevent_var(env, "CU_TYPE=%04X", id->cu_type);
 113         if (ret)
 114                 return ret;
 115
 116         /* CU_MODEL= */
 117         ret = add_uevent_var(env, "CU_MODEL=%02X", id->cu_model);
 118         if (ret)
 119                 return ret;
 120
 121         /* The next two can be zero, that's ok for us */
 122         /* DEV_TYPE= */
 123         ret = add_uevent_var(env, "DEV_TYPE=%04X", id->dev_type);
 124         if (ret)
 125                 return ret;
 126
 127         /* DEV_MODEL= */
 128         ret = add_uevent_var(env, "DEV_MODEL=%02X", id->dev_model);
 129         if (ret)
 130                 return ret;
 131
 132         /* MODALIAS=  */
 133         snprint_alias(modalias_buf, sizeof(modalias_buf), id, "");
 134         ret = add_uevent_var(env, "MODALIAS=%s", modalias_buf);
 135         return ret;
 136 }
 137
 138 static void io_subchannel_irq(struct subchannel *);
 139 static int io_subchannel_probe(struct subchannel *);
 140 static void io_subchannel_remove(struct subchannel *);
 141 static void io_subchannel_shutdown(struct subchannel *);
 142 static int io_subchannel_sch_event(struct subchannel *, int);
 143 static int io_subchannel_chp_event(struct subchannel *, struct chp_link *,
 144                                    int);
 145 static void recovery_func(struct timer_list *unused);
 146
 147 static struct css_device_id io_subchannel_ids[] = {
 148         { .match_flags = 0x1, .type = SUBCHANNEL_TYPE_IO, },
 149         { /* end of list */ },
 150 };
 151
 152 static int io_subchannel_settle(void)
 153 {
 154         int ret;
 155
 156         ret = wait_event_interruptible(ccw_device_init_wq,
 157                                 atomic_read(&ccw_device_init_count) == 0);
 158         if (ret)
 159                 return -EINTR;
 160         flush_workqueue(cio_work_q);
 161         return 0;
 162 }
 163
 164 static struct css_driver io_subchannel_driver = {
 165         .drv = {
 166                 .owner = THIS_MODULE,
 167                 .name = "io_subchannel",
 168         },
 169         .subchannel_type = io_subchannel_ids,
 170         .irq = io_subchannel_irq,
 171         .sch_event = io_subchannel_sch_event,
 172         .chp_event = io_subchannel_chp_event,
 173         .probe = io_subchannel_probe,
 174         .remove = io_subchannel_remove,
 175         .shutdown = io_subchannel_shutdown,
 176         .settle = io_subchannel_settle,
 177 };
 178
 179 int __init io_subchannel_init(void)
 180 {
 181         int ret;
 182
 183         timer_setup(&recovery_timer, recovery_func, 0);
 184         ret = bus_register(&ccw_bus_type);
 185         if (ret)
 186                 return ret;
 187         ret = css_driver_register(&io_subchannel_driver);
 188         if (ret)
 189                 bus_unregister(&ccw_bus_type);
 190
 191         return ret;
 192 }
 193
 194
 195 /************************ device handling **************************/
 196
 197 static ssize_t
 198 devtype_show (struct device *dev, struct device_attribute *attr, char *buf)
 199 {
 200         struct ccw_device *cdev = to_ccwdev(dev);
 201         struct ccw_device_id *id = &(cdev->id);
 202
 203         if (id->dev_type != 0)
 204                 return sprintf(buf, "%04x/%02x\n",
 205                                 id->dev_type, id->dev_model);
 206         else
 207                 return sprintf(buf, "n/a\n");
 208 }
 209
 210 static ssize_t
 211 cutype_show (struct device *dev, struct device_attribute *attr, char *buf)
 212 {
 213         struct ccw_device *cdev = to_ccwdev(dev);
 214         struct ccw_device_id *id = &(cdev->id);
 215
 216         return sprintf(buf, "%04x/%02x\n",
 217                        id->cu_type, id->cu_model);
 218 }
 219
 220 static ssize_t
 221 modalias_show (struct device *dev, struct device_attribute *attr, char *buf)
 222 {
 223         struct ccw_device *cdev = to_ccwdev(dev);
 224         struct ccw_device_id *id = &(cdev->id);
 225         int len;
 226
 227         len = snprint_alias(buf, PAGE_SIZE, id, "\n");
 228
 229         return len > PAGE_SIZE ? PAGE_SIZE : len;
 230 }
 231
 232 static ssize_t
 233 online_show (struct device *dev, struct device_attribute *attr, char *buf)
 234 {
 235         struct ccw_device *cdev = to_ccwdev(dev);
 236
 237         return sprintf(buf, cdev->online ? "1\n" : "0\n");
 238 }
 239
 240 int ccw_device_is_orphan(struct ccw_device *cdev)
 241 {
 242         return sch_is_pseudo_sch(to_subchannel(cdev->dev.parent));
 243 }
 244
 245 static void ccw_device_unregister(struct ccw_device *cdev)
 246 {
 247         if (device_is_registered(&cdev->dev)) {
 248                 /* Undo device_add(). */
 249                 device_del(&cdev->dev);
 250         }
 251         if (cdev->private->flags.initialized) {
 252                 cdev->private->flags.initialized = 0;
 253                 /* Release reference from device_initialize(). */
 254                 put_device(&cdev->dev);
 255         }
 256 }
 257
 258 static void io_subchannel_quiesce(struct subchannel *);
 259
 260 /**
 261  * ccw_device_set_offline() - disable a ccw device for I/O
 262  * @cdev: target ccw device
 263  *
 264  * This function calls the driver's set_offline() function for @cdev, if
 265  * given, and then disables @cdev.
 266  * Returns:
 267  *   %0 on success and a negative error value on failure.
 268  * Context:
 269  *  enabled, ccw device lock not held
 270  */
 271 int ccw_device_set_offline(struct ccw_device *cdev)
 272 {
 273         struct subchannel *sch;
 274         int ret, state;
 275
 276         if (!cdev)
 277                 return -ENODEV;
 278         if (!cdev->online || !cdev->drv)
 279                 return -EINVAL;
 280
 281         if (cdev->drv->set_offline) {
 282                 ret = cdev->drv->set_offline(cdev);
 283                 if (ret != 0)
 284                         return ret;
 285         }
 286         spin_lock_irq(cdev->ccwlock);
 287         sch = to_subchannel(cdev->dev.parent);
 288         cdev->online = 0;
 289         /* Wait until a final state or DISCONNECTED is reached */
 290         while (!dev_fsm_final_state(cdev) &&
 291                cdev->private->state != DEV_STATE_DISCONNECTED) {
 292                 spin_unlock_irq(cdev->ccwlock);
 293                 wait_event(cdev->private->wait_q, (dev_fsm_final_state(cdev) ||
 294                            cdev->private->state == DEV_STATE_DISCONNECTED));
 295                 spin_lock_irq(cdev->ccwlock);
 296         }
 297         do {
 298                 ret = ccw_device_offline(cdev);
 299                 if (!ret)
 300                         break;
 301                 CIO_MSG_EVENT(0, "ccw_device_offline returned %d, device "
 302                               "0.%x.%04x\n", ret, cdev->private->dev_id.ssid,
 303                               cdev->private->dev_id.devno);
 304                 if (ret != -EBUSY)
 305                         goto error;
 306                 state = cdev->private->state;
 307                 spin_unlock_irq(cdev->ccwlock);
 308                 io_subchannel_quiesce(sch);
 309                 spin_lock_irq(cdev->ccwlock);
 310                 cdev->private->state = state;
 311         } while (ret == -EBUSY);
 312         spin_unlock_irq(cdev->ccwlock);
 313         wait_event(cdev->private->wait_q, (dev_fsm_final_state(cdev) ||
 314                    cdev->private->state == DEV_STATE_DISCONNECTED));
 315         /* Inform the user if set offline failed. */
 316         if (cdev->private->state == DEV_STATE_BOXED) {
 317                 pr_warn("%s: The device entered boxed state while being set offline\n",
 318                         dev_name(&cdev->dev));
 319         } else if (cdev->private->state == DEV_STATE_NOT_OPER) {
 320                 pr_warn("%s: The device stopped operating while being set offline\n",
 321                         dev_name(&cdev->dev));
 322         }
 323         /* Give up reference from ccw_device_set_online(). */
 324         put_device(&cdev->dev);
 325         return 0;
 326
 327 error:
 328         cdev->private->state = DEV_STATE_OFFLINE;
 329         dev_fsm_event(cdev, DEV_EVENT_NOTOPER);
 330         spin_unlock_irq(cdev->ccwlock);
 331         /* Give up reference from ccw_device_set_online(). */
 332         put_device(&cdev->dev);
 333         return -ENODEV;
 334 }
 335
 336 /**
 337  * ccw_device_set_online() - enable a ccw device for I/O
 338  * @cdev: target ccw device
 339  *
 340  * This function first enables @cdev and then calls the driver's set_online()
 341  * function for @cdev, if given. If set_online() returns an error, @cdev is
 342  * disabled again.
 343  * Returns:
 344  *   %0 on success and a negative error value on failure.
 345  * Context:
 346  *  enabled, ccw device lock not held
 347  */
 348 int ccw_device_set_online(struct ccw_device *cdev)
 349 {
 350         int ret;
 351         int ret2;
 352
 353         if (!cdev)
 354                 return -ENODEV;
 355         if (cdev->online || !cdev->drv)
 356                 return -EINVAL;
 357         /* Hold on to an extra reference while device is online. */
 358         if (!get_device(&cdev->dev))
 359                 return -ENODEV;
 360
 361         spin_lock_irq(cdev->ccwlock);
 362         ret = ccw_device_online(cdev);
 363         spin_unlock_irq(cdev->ccwlock);
 364         if (ret == 0)
 365                 wait_event(cdev->private->wait_q, dev_fsm_final_state(cdev));
 366         else {
 367                 CIO_MSG_EVENT(0, "ccw_device_online returned %d, "
 368                               "device 0.%x.%04x\n",
 369                               ret, cdev->private->dev_id.ssid,
 370                               cdev->private->dev_id.devno);
 371                 /* Give up online reference since onlining failed. */
 372                 put_device(&cdev->dev);
 373                 return ret;
 374         }
 375         spin_lock_irq(cdev->ccwlock);
 376         /* Check if online processing was successful */
 377         if ((cdev->private->state != DEV_STATE_ONLINE) &&
 378             (cdev->private->state != DEV_STATE_W4SENSE)) {
 379                 spin_unlock_irq(cdev->ccwlock);
 380                 /* Inform the user that set online failed. */
 381                 if (cdev->private->state == DEV_STATE_BOXED) {
 382                         pr_warn("%s: Setting the device online failed because it is boxed\n",
 383                                 dev_name(&cdev->dev));
 384                 } else if (cdev->private->state == DEV_STATE_NOT_OPER) {
 385                         pr_warn("%s: Setting the device online failed because it is not operational\n",
 386                                 dev_name(&cdev->dev));
 387                 }
 388                 /* Give up online reference since onlining failed. */
 389                 put_device(&cdev->dev);
 390                 return -ENODEV;
 391         }
 392         spin_unlock_irq(cdev->ccwlock);
 393         if (cdev->drv->set_online)
 394                 ret = cdev->drv->set_online(cdev);
 395         if (ret)
 396                 goto rollback;
 397
 398         spin_lock_irq(cdev->ccwlock);
 399         cdev->online = 1;
 400         spin_unlock_irq(cdev->ccwlock);
 401         return 0;
 402
 403 rollback:
 404         spin_lock_irq(cdev->ccwlock);
 405         /* Wait until a final state or DISCONNECTED is reached */
 406         while (!dev_fsm_final_state(cdev) &&
 407                cdev->private->state != DEV_STATE_DISCONNECTED) {
 408                 spin_unlock_irq(cdev->ccwlock);
 409                 wait_event(cdev->private->wait_q, (dev_fsm_final_state(cdev) ||
 410                            cdev->private->state == DEV_STATE_DISCONNECTED));
 411                 spin_lock_irq(cdev->ccwlock);
 412         }
 413         ret2 = ccw_device_offline(cdev);
 414         if (ret2)
 415                 goto error;
 416         spin_unlock_irq(cdev->ccwlock);
 417         wait_event(cdev->private->wait_q, (dev_fsm_final_state(cdev) ||
 418                    cdev->private->state == DEV_STATE_DISCONNECTED));
 419         /* Give up online reference since onlining failed. */
 420         put_device(&cdev->dev);
 421         return ret;
 422
 423 error:
 424         CIO_MSG_EVENT(0, "rollback ccw_device_offline returned %d, "
 425                       "device 0.%x.%04x\n",
 426                       ret2, cdev->private->dev_id.ssid,
 427                       cdev->private->dev_id.devno);
 428         cdev->private->state = DEV_STATE_OFFLINE;
 429         spin_unlock_irq(cdev->ccwlock);
 430         /* Give up online reference since onlining failed. */
 431         put_device(&cdev->dev);
 432         return ret;
 433 }
 434
 435 static int online_store_handle_offline(struct ccw_device *cdev)
 436 {
 437         if (cdev->private->state == DEV_STATE_DISCONNECTED) {
 438                 spin_lock_irq(cdev->ccwlock);
 439                 ccw_device_sched_todo(cdev, CDEV_TODO_UNREG_EVAL);
 440                 spin_unlock_irq(cdev->ccwlock);
 441                 return 0;
 442         }
 443         if (cdev->drv && cdev->drv->set_offline)
 444                 return ccw_device_set_offline(cdev);
 445         return -EINVAL;
 446 }
 447
 448 static int online_store_recog_and_online(struct ccw_device *cdev)
 449 {
 450         /* Do device recognition, if needed. */
 451         if (cdev->private->state == DEV_STATE_BOXED) {
 452                 spin_lock_irq(cdev->ccwlock);
 453                 ccw_device_recognition(cdev);
 454                 spin_unlock_irq(cdev->ccwlock);
 455                 wait_event(cdev->private->wait_q,
 456                            cdev->private->flags.recog_done);
 457                 if (cdev->private->state != DEV_STATE_OFFLINE)
 458                         /* recognition failed */
 459                         return -EAGAIN;
 460         }
 461         if (cdev->drv && cdev->drv->set_online)
 462                 return ccw_device_set_online(cdev);
 463         return -EINVAL;
 464 }
 465
 466 static int online_store_handle_online(struct ccw_device *cdev, int force)
 467 {
 468         int ret;
 469
 470         ret = online_store_recog_and_online(cdev);
 471         if (ret && !force)
 472                 return ret;
 473         if (force && cdev->private->state == DEV_STATE_BOXED) {
 474                 ret = ccw_device_stlck(cdev);
 475                 if (ret)
 476                         return ret;
 477                 if (cdev->id.cu_type == 0)
 478                         cdev->private->state = DEV_STATE_NOT_OPER;
 479                 ret = online_store_recog_and_online(cdev);
 480                 if (ret)
 481                         return ret;
 482         }
 483         return 0;
 484 }
 485
 486 static ssize_t online_store (struct device *dev, struct device_attribute *attr,
 487                              const char *buf, size_t count)
 488 {
 489         struct ccw_device *cdev = to_ccwdev(dev);
 490         int force, ret;
 491         unsigned long i;
 492
 493         /* Prevent conflict between multiple on-/offline processing requests. */
 494         if (atomic_cmpxchg(&cdev->private->onoff, 0, 1) != 0)
 495                 return -EAGAIN;
 496         /* Prevent conflict between internal I/Os and on-/offline processing. */
 497         if (!dev_fsm_final_state(cdev) &&
 498             cdev->private->state != DEV_STATE_DISCONNECTED) {
 499                 ret = -EAGAIN;
 500                 goto out;
 501         }
 502         /* Prevent conflict between pending work and on-/offline processing.*/
 503         if (work_pending(&cdev->private->todo_work)) {
 504                 ret = -EAGAIN;
 505                 goto out;
 506         }
 507         if (!strncmp(buf, "force\n", count)) {
 508                 force = 1;
 509                 i = 1;
 510                 ret = 0;
 511         } else {
 512                 force = 0;
 513                 ret = kstrtoul(buf, 16, &i);
 514         }
 515         if (ret)
 516                 goto out;
 517
 518         device_lock(dev);
 519         switch (i) {
 520         case 0:
 521                 ret = online_store_handle_offline(cdev);
 522                 break;
 523         case 1:
 524                 ret = online_store_handle_online(cdev, force);
 525                 break;
 526         default:
 527                 ret = -EINVAL;
 528         }
 529         device_unlock(dev);
 530
 531 out:
 532         atomic_set(&cdev->private->onoff, 0);
 533         return (ret < 0) ? ret : count;
 534 }
 535
 536 static ssize_t
 537 available_show (struct device *dev, struct device_attribute *attr, char *buf)
 538 {
 539         struct ccw_device *cdev = to_ccwdev(dev);
 540         struct subchannel *sch;
 541
 542         if (ccw_device_is_orphan(cdev))
 543                 return sprintf(buf, "no device\n");
 544         switch (cdev->private->state) {
 545         case DEV_STATE_BOXED:
 546                 return sprintf(buf, "boxed\n");
 547         case DEV_STATE_DISCONNECTED:
 548         case DEV_STATE_DISCONNECTED_SENSE_ID:
 549         case DEV_STATE_NOT_OPER:
 550                 sch = to_subchannel(dev->parent);
 551                 if (!sch->lpm)
 552                         return sprintf(buf, "no path\n");
 553                 else
 554                         return sprintf(buf, "no device\n");
 555         default:
 556                 /* All other states considered fine. */
 557                 return sprintf(buf, "good\n");
 558         }
 559 }
 560
 561 static ssize_t
 562 initiate_logging(struct device *dev, struct device_attribute *attr,
 563                  const char *buf, size_t count)
 564 {
 565         struct subchannel *sch = to_subchannel(dev);
 566         int rc;
 567
 568         rc = chsc_siosl(sch->schid);
 569         if (rc < 0) {
 570                 pr_warn("Logging for subchannel 0.%x.%04x failed with errno=%d\n",
 571                         sch->schid.ssid, sch->schid.sch_no, rc);
 572                 return rc;
 573         }
 574         pr_notice("Logging for subchannel 0.%x.%04x was triggered\n",
 575                   sch->schid.ssid, sch->schid.sch_no);
 576         return count;
 577 }
 578
 579 static ssize_t vpm_show(struct device *dev, struct device_attribute *attr,
 580                         char *buf)
 581 {
 582         struct subchannel *sch = to_subchannel(dev);
 583
 584         return sprintf(buf, "%02x\n", sch->vpm);
 585 }
 586
 587 static DEVICE_ATTR_RO(devtype);
 588 static DEVICE_ATTR_RO(cutype);
 589 static DEVICE_ATTR_RO(modalias);
 590 static DEVICE_ATTR_RW(online);
 591 static DEVICE_ATTR(availability, 0444, available_show, NULL);
 592 static DEVICE_ATTR(logging, 0200, NULL, initiate_logging);
 593 static DEVICE_ATTR_RO(vpm);
 594
 595 static struct attribute *io_subchannel_attrs[] = {
 596         &dev_attr_logging.attr,
 597         &dev_attr_vpm.attr,
 598         NULL,
 599 };
 600
 601 static const struct attribute_group io_subchannel_attr_group = {
 602         .attrs = io_subchannel_attrs,
 603 };
 604
 605 static struct attribute * ccwdev_attrs[] = {
 606         &dev_attr_devtype.attr,
 607         &dev_attr_cutype.attr,
 608         &dev_attr_modalias.attr,
 609         &dev_attr_online.attr,
 610         &dev_attr_cmb_enable.attr,
 611         &dev_attr_availability.attr,
 612         NULL,
 613 };
 614
 615 static const struct attribute_group ccwdev_attr_group = {
 616         .attrs = ccwdev_attrs,
 617 };
 618
 619 static const struct attribute_group *ccwdev_attr_groups[] = {
 620         &ccwdev_attr_group,
 621         NULL,
 622 };
 623
 624 static int match_dev_id(struct device *dev, const void *data)
 625 {
 626         struct ccw_device *cdev = to_ccwdev(dev);
 627         struct ccw_dev_id *dev_id = (void *)data;
 628
 629         return ccw_dev_id_is_equal(&cdev->private->dev_id, dev_id);
 630 }
 631
 632 /**
 633  * get_ccwdev_by_dev_id() - obtain device from a ccw device id
 634  * @dev_id: id of the device to be searched
 635  *
 636  * This function searches all devices attached to the ccw bus for a device
 637  * matching @dev_id.
 638  * Returns:
 639  *  If a device is found its reference count is increased and returned;
 640  *  else %NULL is returned.
 641  */
 642 struct ccw_device *get_ccwdev_by_dev_id(struct ccw_dev_id *dev_id)
 643 {
 644         struct device *dev;
 645
 646         dev = bus_find_device(&ccw_bus_type, NULL, dev_id, match_dev_id);
 647
 648         return dev ? to_ccwdev(dev) : NULL;
 649 }
 650 EXPORT_SYMBOL_GPL(get_ccwdev_by_dev_id);
 651
 652 static void ccw_device_do_unbind_bind(struct ccw_device *cdev)
 653 {
 654         int ret;
 655
 656         if (device_is_registered(&cdev->dev)) {
 657                 device_release_driver(&cdev->dev);
 658                 ret = device_attach(&cdev->dev);
 659                 WARN_ON(ret == -ENODEV);
 660         }
 661 }
 662
 663 static void
 664 ccw_device_release(struct device *dev)
 665 {
 666         struct ccw_device *cdev;
 667
 668         cdev = to_ccwdev(dev);
 669         cio_gp_dma_free(cdev->private->dma_pool, cdev->private->dma_area,
 670                         sizeof(*cdev->private->dma_area));
 671         cio_gp_dma_destroy(cdev->private->dma_pool, &cdev->dev);
 672         /* Release reference of parent subchannel. */
 673         put_device(cdev->dev.parent);
 674         kfree(cdev->private);
 675         kfree(cdev);
 676 }
 677
 678 static struct ccw_device * io_subchannel_allocate_dev(struct subchannel *sch)
 679 {
 680         struct ccw_device *cdev;
 681         struct gen_pool *dma_pool;
 682         int ret;
 683
 684         cdev  = kzalloc(sizeof(*cdev), GFP_KERNEL);
 685         if (!cdev) {
 686                 ret = -ENOMEM;
 687                 goto err_cdev;
 688         }
 689         cdev->private = kzalloc(sizeof(struct ccw_device_private),
 690                                 GFP_KERNEL | GFP_DMA);
 691         if (!cdev->private) {
 692                 ret = -ENOMEM;
 693                 goto err_priv;
 694         }
 695
 696         cdev->dev.dma_mask = sch->dev.dma_mask;
 697         ret = dma_set_coherent_mask(&cdev->dev, sch->dev.coherent_dma_mask);
 698         if (ret)
 699                 goto err_coherent_mask;
 700
 701         dma_pool = cio_gp_dma_create(&cdev->dev, 1);
 702         if (!dma_pool) {
 703                 ret = -ENOMEM;
 704                 goto err_dma_pool;
 705         }
 706         cdev->private->dma_pool = dma_pool;
 707         cdev->private->dma_area = cio_gp_dma_zalloc(dma_pool, &cdev->dev,
 708                                         sizeof(*cdev->private->dma_area));
 709         if (!cdev->private->dma_area) {
 710                 ret = -ENOMEM;
 711                 goto err_dma_area;
 712         }
 713         return cdev;
 714 err_dma_area:
 715         cio_gp_dma_destroy(dma_pool, &cdev->dev);
 716 err_dma_pool:
 717 err_coherent_mask:
 718         kfree(cdev->private);
 719 err_priv:
 720         kfree(cdev);
 721 err_cdev:
 722         return ERR_PTR(ret);
 723 }
 724
 725 static void ccw_device_todo(struct work_struct *work);
 726
 727 static int io_subchannel_initialize_dev(struct subchannel *sch,
 728                                         struct ccw_device *cdev)
 729 {
 730         struct ccw_device_private *priv = cdev->private;
 731         int ret;
 732
 733         priv->cdev = cdev;
 734         priv->int_class = IRQIO_CIO;
 735         priv->state = DEV_STATE_NOT_OPER;
 736         priv->dev_id.devno = sch->schib.pmcw.dev;
 737         priv->dev_id.ssid = sch->schid.ssid;
 738
 739         INIT_WORK(&priv->todo_work, ccw_device_todo);
 740         INIT_LIST_HEAD(&priv->cmb_list);
 741         init_waitqueue_head(&priv->wait_q);
 742         timer_setup(&priv->timer, ccw_device_timeout, 0);
 743
 744         atomic_set(&priv->onoff, 0);
 745         cdev->ccwlock = sch->lock;
 746         cdev->dev.parent = &sch->dev;
 747         cdev->dev.release = ccw_device_release;
 748         cdev->dev.bus = &ccw_bus_type;
 749         cdev->dev.groups = ccwdev_attr_groups;
 750         /* Do first half of device_register. */
 751         device_initialize(&cdev->dev);
 752         ret = dev_set_name(&cdev->dev, "0.%x.%04x", cdev->private->dev_id.ssid,
 753                            cdev->private->dev_id.devno);
 754         if (ret)
 755                 goto out_put;
 756         if (!get_device(&sch->dev)) {
 757                 ret = -ENODEV;
 758                 goto out_put;
 759         }
 760         priv->flags.initialized = 1;
 761         spin_lock_irq(sch->lock);
 762         sch_set_cdev(sch, cdev);
 763         spin_unlock_irq(sch->lock);
 764         return 0;
 765
 766 out_put:
 767         /* Release reference from device_initialize(). */
 768         put_device(&cdev->dev);
 769         return ret;
 770 }
 771
 772 static struct ccw_device * io_subchannel_create_ccwdev(struct subchannel *sch)
 773 {
 774         struct ccw_device *cdev;
 775         int ret;
 776
 777         cdev = io_subchannel_allocate_dev(sch);
 778         if (!IS_ERR(cdev)) {
 779                 ret = io_subchannel_initialize_dev(sch, cdev);
 780                 if (ret)
 781                         cdev = ERR_PTR(ret);
 782         }
 783         return cdev;
 784 }
 785
 786 static void io_subchannel_recog(struct ccw_device *, struct subchannel *);
 787
 788 static void sch_create_and_recog_new_device(struct subchannel *sch)
 789 {
 790         struct ccw_device *cdev;
 791
 792         /* Need to allocate a new ccw device. */
 793         cdev = io_subchannel_create_ccwdev(sch);
 794         if (IS_ERR(cdev)) {
 795                 /* OK, we did everything we could... */
 796                 css_sch_device_unregister(sch);
 797                 return;
 798         }
 799         /* Start recognition for the new ccw device. */
 800         io_subchannel_recog(cdev, sch);
 801 }
 802
 803 /*
 804  * Register recognized device.
 805  */
 806 static void io_subchannel_register(struct ccw_device *cdev)
 807 {
 808         struct subchannel *sch;
 809         int ret, adjust_init_count = 1;
 810         unsigned long flags;
 811
 812         sch = to_subchannel(cdev->dev.parent);
 813         /*
 814          * Check if subchannel is still registered. It may have become
 815          * unregistered if a machine check hit us after finishing
 816          * device recognition but before the register work could be
 817          * queued.
 818          */
 819         if (!device_is_registered(&sch->dev))
 820                 goto out_err;
 821         css_update_ssd_info(sch);
 822         /*
 823          * io_subchannel_register() will also be called after device
 824          * recognition has been done for a boxed device (which will already
 825          * be registered). We need to reprobe since we may now have sense id
 826          * information.
 827          */
 828         if (device_is_registered(&cdev->dev)) {
 829                 if (!cdev->drv) {
 830                         ret = device_reprobe(&cdev->dev);
 831                         if (ret)
 832                                 /* We can't do much here. */
 833                                 CIO_MSG_EVENT(0, "device_reprobe() returned"
 834                                               " %d for 0.%x.%04x\n", ret,
 835                                               cdev->private->dev_id.ssid,
 836                                               cdev->private->dev_id.devno);
 837                 }
 838                 adjust_init_count = 0;
 839                 goto out;
 840         }
 841         /*
 842          * Now we know this subchannel will stay, we can throw
 843          * our delayed uevent.
 844          */
 845         if (dev_get_uevent_suppress(&sch->dev)) {
 846                 dev_set_uevent_suppress(&sch->dev, 0);
 847                 kobject_uevent(&sch->dev.kobj, KOBJ_ADD);
 848         }
 849         /* make it known to the system */
 850         ret = device_add(&cdev->dev);
 851         if (ret) {
 852                 CIO_MSG_EVENT(0, "Could not register ccw dev 0.%x.%04x: %d\n",
 853                               cdev->private->dev_id.ssid,
 854                               cdev->private->dev_id.devno, ret);
 855                 spin_lock_irqsave(sch->lock, flags);
 856                 sch_set_cdev(sch, NULL);
 857                 spin_unlock_irqrestore(sch->lock, flags);
 858                 /* Release initial device reference. */
 859                 put_device(&cdev->dev);
 860                 goto out_err;
 861         }
 862 out:
 863         cdev->private->flags.recog_done = 1;
 864         wake_up(&cdev->private->wait_q);
 865 out_err:
 866         if (adjust_init_count && atomic_dec_and_test(&ccw_device_init_count))
 867                 wake_up(&ccw_device_init_wq);
 868 }
 869
 870 static void ccw_device_call_sch_unregister(struct ccw_device *cdev)
 871 {
 872         struct subchannel *sch;
 873
 874         /* Get subchannel reference for local processing. */
 875         if (!get_device(cdev->dev.parent))
 876                 return;
 877         sch = to_subchannel(cdev->dev.parent);
 878         css_sch_device_unregister(sch);
 879         /* Release subchannel reference for local processing. */
 880         put_device(&sch->dev);
 881 }
 882
 883 /*
 884  * subchannel recognition done. Called from the state machine.
 885  */
 886 void
 887 io_subchannel_recog_done(struct ccw_device *cdev)
 888 {
 889         if (css_init_done == 0) {
 890                 cdev->private->flags.recog_done = 1;
 891                 return;
 892         }
 893         switch (cdev->private->state) {
 894         case DEV_STATE_BOXED:
 895                 /* Device did not respond in time. */
 896         case DEV_STATE_NOT_OPER:
 897                 cdev->private->flags.recog_done = 1;
 898                 /* Remove device found not operational. */
 899                 ccw_device_sched_todo(cdev, CDEV_TODO_UNREG);
 900                 if (atomic_dec_and_test(&ccw_device_init_count))
 901                         wake_up(&ccw_device_init_wq);
 902                 break;
 903         case DEV_STATE_OFFLINE:
 904                 /*
 905                  * We can't register the device in interrupt context so
 906                  * we schedule a work item.
 907                  */
 908                 ccw_device_sched_todo(cdev, CDEV_TODO_REGISTER);
 909                 break;
 910         }
 911 }
 912
 913 static void io_subchannel_recog(struct ccw_device *cdev, struct subchannel *sch)
 914 {
 915         /* Increase counter of devices currently in recognition. */
 916         atomic_inc(&ccw_device_init_count);
 917
 918         /* Start async. device sensing. */
 919         spin_lock_irq(sch->lock);
 920         ccw_device_recognition(cdev);
 921         spin_unlock_irq(sch->lock);
 922 }
 923
 924 static int ccw_device_move_to_sch(struct ccw_device *cdev,
 925                                   struct subchannel *sch)
 926 {
 927         struct subchannel *old_sch;
 928         int rc, old_enabled = 0;
 929
 930         old_sch = to_subchannel(cdev->dev.parent);
 931         /* Obtain child reference for new parent. */
 932         if (!get_device(&sch->dev))
 933                 return -ENODEV;
 934
 935         if (!sch_is_pseudo_sch(old_sch)) {
 936                 spin_lock_irq(old_sch->lock);
 937                 old_enabled = old_sch->schib.pmcw.ena;
 938                 rc = 0;
 939                 if (old_enabled)
 940                         rc = cio_disable_subchannel(old_sch);
 941                 spin_unlock_irq(old_sch->lock);
 942                 if (rc == -EBUSY) {
 943                         /* Release child reference for new parent. */
 944                         put_device(&sch->dev);
 945                         return rc;
 946                 }
 947         }
 948
 949         mutex_lock(&sch->reg_mutex);
 950         rc = device_move(&cdev->dev, &sch->dev, DPM_ORDER_PARENT_BEFORE_DEV);
 951         mutex_unlock(&sch->reg_mutex);
 952         if (rc) {
 953                 CIO_MSG_EVENT(0, "device_move(0.%x.%04x,0.%x.%04x)=%d\n",
 954                               cdev->private->dev_id.ssid,
 955                               cdev->private->dev_id.devno, sch->schid.ssid,
 956                               sch->schib.pmcw.dev, rc);
 957                 if (old_enabled) {
 958                         /* Try to reenable the old subchannel. */
 959                         spin_lock_irq(old_sch->lock);
 960                         cio_enable_subchannel(old_sch, (u32)(addr_t)old_sch);
 961                         spin_unlock_irq(old_sch->lock);
 962                 }
 963                 /* Release child reference for new parent. */
 964                 put_device(&sch->dev);
 965                 return rc;
 966         }
 967         /* Clean up old subchannel. */
 968         if (!sch_is_pseudo_sch(old_sch)) {
 969                 spin_lock_irq(old_sch->lock);
 970                 sch_set_cdev(old_sch, NULL);
 971                 spin_unlock_irq(old_sch->lock);
 972                 css_schedule_eval(old_sch->schid);
 973         }
 974         /* Release child reference for old parent. */
 975         put_device(&old_sch->dev);
 976         /* Initialize new subchannel. */
 977         spin_lock_irq(sch->lock);
 978         cdev->ccwlock = sch->lock;
 979         if (!sch_is_pseudo_sch(sch))
 980                 sch_set_cdev(sch, cdev);
 981         spin_unlock_irq(sch->lock);
 982         if (!sch_is_pseudo_sch(sch))
 983                 css_update_ssd_info(sch);
 984         return 0;
 985 }
 986
 987 static int ccw_device_move_to_orph(struct ccw_device *cdev)
 988 {
 989         struct subchannel *sch = to_subchannel(cdev->dev.parent);
 990         struct channel_subsystem *css = to_css(sch->dev.parent);
 991
 992         return ccw_device_move_to_sch(cdev, css->pseudo_subchannel);
 993 }
 994
 995 static void io_subchannel_irq(struct subchannel *sch)
 996 {
 997         struct ccw_device *cdev;
 998
 999         cdev = sch_get_cdev(sch);
1000
1001         CIO_TRACE_EVENT(6, "IRQ");
1002         CIO_TRACE_EVENT(6, dev_name(&sch->dev));
1003         if (cdev)
1004                 dev_fsm_event(cdev, DEV_EVENT_INTERRUPT);
1005         else
1006                 inc_irq_stat(IRQIO_CIO);
1007 }
1008
1009 void io_subchannel_init_config(struct subchannel *sch)
1010 {
1011         memset(&sch->config, 0, sizeof(sch->config));
1012         sch->config.csense = 1;
1013 }
1014
1015 static void io_subchannel_init_fields(struct subchannel *sch)
1016 {
1017         if (cio_is_console(sch->schid))
1018                 sch->opm = 0xff;
1019         else
1020                 sch->opm = chp_get_sch_opm(sch);
1021         sch->lpm = sch->schib.pmcw.pam & sch->opm;
1022         sch->isc = cio_is_console(sch->schid) ? CONSOLE_ISC : IO_SCH_ISC;
1023
1024         CIO_MSG_EVENT(6, "Detected device %04x on subchannel 0.%x.%04X"
1025                       " - PIM = %02X, PAM = %02X, POM = %02X\n",
1026                       sch->schib.pmcw.dev, sch->schid.ssid,
1027                       sch->schid.sch_no, sch->schib.pmcw.pim,
1028                       sch->schib.pmcw.pam, sch->schib.pmcw.pom);
1029
1030         io_subchannel_init_config(sch);
1031 }
1032
1033 /*
1034  * Note: We always return 0 so that we bind to the device even on error.
1035  * This is needed so that our remove function is called on unregister.
1036  */
1037 static int io_subchannel_probe(struct subchannel *sch)
1038 {
1039         struct io_subchannel_private *io_priv;
1040         struct ccw_device *cdev;
1041         int rc;
1042
1043         if (cio_is_console(sch->schid)) {
1044                 rc = sysfs_create_group(&sch->dev.kobj,
1045                                         &io_subchannel_attr_group);
1046                 if (rc)
1047                         CIO_MSG_EVENT(0, "Failed to create io subchannel "
1048                                       "attributes for subchannel "
1049                                       "0.%x.%04x (rc=%d)\n",
1050                                       sch->schid.ssid, sch->schid.sch_no, rc);
1051                 /*
1052                  * The console subchannel already has an associated ccw_device.
1053                  * Throw the delayed uevent for the subchannel, register
1054                  * the ccw_device and exit.
1055                  */
1056                 if (dev_get_uevent_suppress(&sch->dev)) {
1057                         /* should always be the case for the console */
1058                         dev_set_uevent_suppress(&sch->dev, 0);
1059                         kobject_uevent(&sch->dev.kobj, KOBJ_ADD);
1060                 }
1061                 cdev = sch_get_cdev(sch);
1062                 rc = device_add(&cdev->dev);
1063                 if (rc) {
1064                         /* Release online reference. */
1065                         put_device(&cdev->dev);
1066                         goto out_schedule;
1067                 }
1068                 if (atomic_dec_and_test(&ccw_device_init_count))
1069                         wake_up(&ccw_device_init_wq);
1070                 return 0;
1071         }
1072         io_subchannel_init_fields(sch);
1073         rc = cio_commit_config(sch);
1074         if (rc)
1075                 goto out_schedule;
1076         rc = sysfs_create_group(&sch->dev.kobj,
1077                                 &io_subchannel_attr_group);
1078         if (rc)
1079                 goto out_schedule;
1080         /* Allocate I/O subchannel private data. */
1081         io_priv = kzalloc(sizeof(*io_priv), GFP_KERNEL | GFP_DMA);
1082         if (!io_priv)
1083                 goto out_schedule;
1084
1085         io_priv->dma_area = dma_alloc_coherent(&sch->dev,
1086                                 sizeof(*io_priv->dma_area),
1087                                 &io_priv->dma_area_dma, GFP_KERNEL);
1088         if (!io_priv->dma_area) {
1089                 kfree(io_priv);
1090                 goto out_schedule;
1091         }
1092
1093         set_io_private(sch, io_priv);
1094         css_schedule_eval(sch->schid);
1095         return 0;
1096
1097 out_schedule:
1098         spin_lock_irq(sch->lock);
1099         css_sched_sch_todo(sch, SCH_TODO_UNREG);
1100         spin_unlock_irq(sch->lock);
1101         return 0;
1102 }
1103
1104 static void io_subchannel_remove(struct subchannel *sch)
1105 {
1106         struct io_subchannel_private *io_priv = to_io_private(sch);
1107         struct ccw_device *cdev;
1108
1109         cdev = sch_get_cdev(sch);
1110         if (!cdev)
1111                 goto out_free;
1112
1113         ccw_device_unregister(cdev);
1114         spin_lock_irq(sch->lock);
1115         sch_set_cdev(sch, NULL);
1116         set_io_private(sch, NULL);
1117         spin_unlock_irq(sch->lock);
1118 out_free:
1119         dma_free_coherent(&sch->dev, sizeof(*io_priv->dma_area),
1120                           io_priv->dma_area, io_priv->dma_area_dma);
1121         kfree(io_priv);
1122         sysfs_remove_group(&sch->dev.kobj, &io_subchannel_attr_group);
1123 }
1124
1125 static void io_subchannel_verify(struct subchannel *sch)
1126 {
1127         struct ccw_device *cdev;
1128
1129         cdev = sch_get_cdev(sch);
1130         if (cdev)
1131                 dev_fsm_event(cdev, DEV_EVENT_VERIFY);
1132 }
1133
1134 static void io_subchannel_terminate_path(struct subchannel *sch, u8 mask)
1135 {
1136         struct ccw_device *cdev;
1137
1138         cdev = sch_get_cdev(sch);
1139         if (!cdev)
1140                 return;
1141         if (cio_update_schib(sch))
1142                 goto err;
1143         /* Check for I/O on path. */
1144         if (scsw_actl(&sch->schib.scsw) == 0 || sch->schib.pmcw.lpum != mask)
1145                 goto out;
1146         if (cdev->private->state == DEV_STATE_ONLINE) {
1147                 ccw_device_kill_io(cdev);
1148                 goto out;
1149         }
1150         if (cio_clear(sch))
1151                 goto err;
1152 out:
1153         /* Trigger path verification. */
1154         dev_fsm_event(cdev, DEV_EVENT_VERIFY);
1155         return;
1156
1157 err:
1158         dev_fsm_event(cdev, DEV_EVENT_NOTOPER);
1159 }
1160
1161 static int io_subchannel_chp_event(struct subchannel *sch,
1162                                    struct chp_link *link, int event)
1163 {
1164         struct ccw_device *cdev = sch_get_cdev(sch);
1165         int mask, chpid, valid_bit;
1166         int path_event[8];
1167
1168         mask = chp_ssd_get_mask(&sch->ssd_info, link);
1169         if (!mask)
1170                 return 0;
1171         switch (event) {
1172         case CHP_VARY_OFF:
1173                 sch->opm &= ~mask;
1174                 sch->lpm &= ~mask;
1175                 if (cdev)
1176                         cdev->private->path_gone_mask |= mask;
1177                 io_subchannel_terminate_path(sch, mask);
1178                 break;
1179         case CHP_VARY_ON:
1180                 sch->opm |= mask;
1181                 sch->lpm |= mask;
1182                 if (cdev)
1183                         cdev->private->path_new_mask |= mask;
1184                 io_subchannel_verify(sch);
1185                 break;
1186         case CHP_OFFLINE:
1187                 if (cio_update_schib(sch))
1188                         return -ENODEV;
1189                 if (cdev)
1190                         cdev->private->path_gone_mask |= mask;
1191                 io_subchannel_terminate_path(sch, mask);
1192                 break;
1193         case CHP_ONLINE:
1194                 if (cio_update_schib(sch))
1195                         return -ENODEV;
1196                 sch->lpm |= mask & sch->opm;
1197                 if (cdev)
1198                         cdev->private->path_new_mask |= mask;
1199                 io_subchannel_verify(sch);
1200                 break;
1201         case CHP_FCES_EVENT:
1202                 /* Forward Endpoint Security event */
1203                 for (chpid = 0, valid_bit = 0x80; chpid < 8; chpid++,
1204                                 valid_bit >>= 1) {
1205                         if (mask & valid_bit)
1206                                 path_event[chpid] = PE_PATH_FCES_EVENT;
1207                         else
1208                                 path_event[chpid] = PE_NONE;
1209                 }
1210                 if (cdev)
1211                         cdev->drv->path_event(cdev, path_event);
1212                 break;
1213         }
1214         return 0;
1215 }
1216
1217 static void io_subchannel_quiesce(struct subchannel *sch)
1218 {
1219         struct ccw_device *cdev;
1220         int ret;
1221
1222         spin_lock_irq(sch->lock);
1223         cdev = sch_get_cdev(sch);
1224         if (cio_is_console(sch->schid))
1225                 goto out_unlock;
1226         if (!sch->schib.pmcw.ena)
1227                 goto out_unlock;
1228         ret = cio_disable_subchannel(sch);
1229         if (ret != -EBUSY)
1230                 goto out_unlock;
1231         if (cdev->handler)
1232                 cdev->handler(cdev, cdev->private->intparm, ERR_PTR(-EIO));
1233         while (ret == -EBUSY) {
1234                 cdev->private->state = DEV_STATE_QUIESCE;
1235                 cdev->private->iretry = 255;
1236                 ret = ccw_device_cancel_halt_clear(cdev);
1237                 if (ret == -EBUSY) {
1238                         ccw_device_set_timeout(cdev, HZ/10);
1239                         spin_unlock_irq(sch->lock);
1240                         wait_event(cdev->private->wait_q,
1241                                    cdev->private->state != DEV_STATE_QUIESCE);
1242                         spin_lock_irq(sch->lock);
1243                 }
1244                 ret = cio_disable_subchannel(sch);
1245         }
1246 out_unlock:
1247         spin_unlock_irq(sch->lock);
1248 }
1249
1250 static void io_subchannel_shutdown(struct subchannel *sch)
1251 {
1252         io_subchannel_quiesce(sch);
1253 }
1254
1255 static int device_is_disconnected(struct ccw_device *cdev)
1256 {
1257         if (!cdev)
1258                 return 0;
1259         return (cdev->private->state == DEV_STATE_DISCONNECTED ||
1260                 cdev->private->state == DEV_STATE_DISCONNECTED_SENSE_ID);
1261 }
1262
1263 static int recovery_check(struct device *dev, void *data)
1264 {
1265         struct ccw_device *cdev = to_ccwdev(dev);
1266         struct subchannel *sch;
1267         int *redo = data;
1268
1269         spin_lock_irq(cdev->ccwlock);
1270         switch (cdev->private->state) {
1271         case DEV_STATE_ONLINE:
1272                 sch = to_subchannel(cdev->dev.parent);
1273                 if ((sch->schib.pmcw.pam & sch->opm) == sch->vpm)
1274                         break;
1275                 fallthrough;
1276         case DEV_STATE_DISCONNECTED:
1277                 CIO_MSG_EVENT(3, "recovery: trigger 0.%x.%04x\n",
1278                               cdev->private->dev_id.ssid,
1279                               cdev->private->dev_id.devno);
1280                 dev_fsm_event(cdev, DEV_EVENT_VERIFY);
1281                 *redo = 1;
1282                 break;
1283         case DEV_STATE_DISCONNECTED_SENSE_ID:
1284                 *redo = 1;
1285                 break;
1286         }
1287         spin_unlock_irq(cdev->ccwlock);
1288
1289         return 0;
1290 }
1291
1292 static void recovery_work_func(struct work_struct *unused)
1293 {
1294         int redo = 0;
1295
1296         bus_for_each_dev(&ccw_bus_type, NULL, &redo, recovery_check);
1297         if (redo) {
1298                 spin_lock_irq(&recovery_lock);
1299                 if (!timer_pending(&recovery_timer)) {
1300                         if (recovery_phase < ARRAY_SIZE(recovery_delay) - 1)
1301                                 recovery_phase++;
1302                         mod_timer(&recovery_timer, jiffies +
1303                                   recovery_delay[recovery_phase] * HZ);
1304                 }
1305                 spin_unlock_irq(&recovery_lock);
1306         } else
1307                 CIO_MSG_EVENT(3, "recovery: end\n");
1308 }
1309
1310 static DECLARE_WORK(recovery_work, recovery_work_func);
1311
1312 static void recovery_func(struct timer_list *unused)
1313 {
1314         /*
1315          * We can't do our recovery in softirq context and it's not
1316          * performance critical, so we schedule it.
1317          */
1318         schedule_work(&recovery_work);
1319 }
1320
1321 void ccw_device_schedule_recovery(void)
1322 {
1323         unsigned long flags;
1324
1325         CIO_MSG_EVENT(3, "recovery: schedule\n");
1326         spin_lock_irqsave(&recovery_lock, flags);
1327         if (!timer_pending(&recovery_timer) || (recovery_phase != 0)) {
1328                 recovery_phase = 0;
1329                 mod_timer(&recovery_timer, jiffies + recovery_delay[0] * HZ);
1330         }
1331         spin_unlock_irqrestore(&recovery_lock, flags);
1332 }
1333
1334 static int purge_fn(struct device *dev, void *data)
1335 {
1336         struct ccw_device *cdev = to_ccwdev(dev);
1337         struct ccw_dev_id *id = &cdev->private->dev_id;
1338
1339         spin_lock_irq(cdev->ccwlock);
1340         if (is_blacklisted(id->ssid, id->devno) &&
1341             (cdev->private->state == DEV_STATE_OFFLINE) &&
1342             (atomic_cmpxchg(&cdev->private->onoff, 0, 1) == 0)) {
1343                 CIO_MSG_EVENT(3, "ccw: purging 0.%x.%04x\n", id->ssid,
1344                               id->devno);
1345                 ccw_device_sched_todo(cdev, CDEV_TODO_UNREG);
1346                 atomic_set(&cdev->private->onoff, 0);
1347         }
1348         spin_unlock_irq(cdev->ccwlock);
1349         /* Abort loop in case of pending signal. */
1350         if (signal_pending(current))
1351                 return -EINTR;
1352
1353         return 0;
1354 }
1355
1356 /**
1357  * ccw_purge_blacklisted - purge unused, blacklisted devices
1358  *
1359  * Unregister all ccw devices that are offline and on the blacklist.
1360  */
1361 int ccw_purge_blacklisted(void)
1362 {
1363         CIO_MSG_EVENT(2, "ccw: purging blacklisted devices\n");
1364         bus_for_each_dev(&ccw_bus_type, NULL, NULL, purge_fn);
1365         return 0;
1366 }
1367
1368 void ccw_device_set_disconnected(struct ccw_device *cdev)
1369 {
1370         if (!cdev)
1371                 return;
1372         ccw_device_set_timeout(cdev, 0);
1373         cdev->private->flags.fake_irb = 0;
1374         cdev->private->state = DEV_STATE_DISCONNECTED;
1375         if (cdev->online)
1376                 ccw_device_schedule_recovery();
1377 }
1378
1379 void ccw_device_set_notoper(struct ccw_device *cdev)
1380 {
1381         struct subchannel *sch = to_subchannel(cdev->dev.parent);
1382
1383         CIO_TRACE_EVENT(2, "notoper");
1384         CIO_TRACE_EVENT(2, dev_name(&sch->dev));
1385         ccw_device_set_timeout(cdev, 0);
1386         cio_disable_subchannel(sch);
1387         cdev->private->state = DEV_STATE_NOT_OPER;
1388 }
1389
1390 enum io_sch_action {
1391         IO_SCH_UNREG,
1392         IO_SCH_ORPH_UNREG,
1393         IO_SCH_ATTACH,
1394         IO_SCH_UNREG_ATTACH,
1395         IO_SCH_ORPH_ATTACH,
1396         IO_SCH_REPROBE,
1397         IO_SCH_VERIFY,
1398         IO_SCH_DISC,
1399         IO_SCH_NOP,
1400 };
1401
1402 static enum io_sch_action sch_get_action(struct subchannel *sch)
1403 {
1404         struct ccw_device *cdev;
1405
1406         cdev = sch_get_cdev(sch);
1407         if (cio_update_schib(sch)) {
1408                 /* Not operational. */
1409                 if (!cdev)
1410                         return IO_SCH_UNREG;
1411                 if (ccw_device_notify(cdev, CIO_GONE) != NOTIFY_OK)
1412                         return IO_SCH_UNREG;
1413                 return IO_SCH_ORPH_UNREG;
1414         }
1415         /* Operational. */
1416         if (!cdev)
1417                 return IO_SCH_ATTACH;
1418         if (sch->schib.pmcw.dev != cdev->private->dev_id.devno) {
1419                 if (ccw_device_notify(cdev, CIO_GONE) != NOTIFY_OK)
1420                         return IO_SCH_UNREG_ATTACH;
1421                 return IO_SCH_ORPH_ATTACH;
1422         }
1423         if ((sch->schib.pmcw.pam & sch->opm) == 0) {
1424                 if (ccw_device_notify(cdev, CIO_NO_PATH) != NOTIFY_OK)
1425                         return IO_SCH_UNREG;
1426                 return IO_SCH_DISC;
1427         }
1428         if (device_is_disconnected(cdev))
1429                 return IO_SCH_REPROBE;
1430         if (cdev->online)
1431                 return IO_SCH_VERIFY;
1432         if (cdev->private->state == DEV_STATE_NOT_OPER)
1433                 return IO_SCH_UNREG_ATTACH;
1434         return IO_SCH_NOP;
1435 }
1436
1437 /**
1438  * io_subchannel_sch_event - process subchannel event
1439  * @sch: subchannel
1440  * @process: non-zero if function is called in process context
1441  *
1442  * An unspecified event occurred for this subchannel. Adjust data according
1443  * to the current operational state of the subchannel and device. Return
1444  * zero when the event has been handled sufficiently or -EAGAIN when this
1445  * function should be called again in process context.
1446  */
1447 static int io_subchannel_sch_event(struct subchannel *sch, int process)
1448 {
1449         unsigned long flags;
1450         struct ccw_device *cdev;
1451         struct ccw_dev_id dev_id;
1452         enum io_sch_action action;
1453         int rc = -EAGAIN;
1454
1455         spin_lock_irqsave(sch->lock, flags);
1456         if (!device_is_registered(&sch->dev))
1457                 goto out_unlock;
1458         if (work_pending(&sch->todo_work))
1459                 goto out_unlock;
1460         cdev = sch_get_cdev(sch);
1461         if (cdev && work_pending(&cdev->private->todo_work))
1462                 goto out_unlock;
1463         action = sch_get_action(sch);
1464         CIO_MSG_EVENT(2, "event: sch 0.%x.%04x, process=%d, action=%d\n",
1465                       sch->schid.ssid, sch->schid.sch_no, process,
1466                       action);
1467         /* Perform immediate actions while holding the lock. */
1468         switch (action) {
1469         case IO_SCH_REPROBE:
1470                 /* Trigger device recognition. */
1471                 ccw_device_trigger_reprobe(cdev);
1472                 rc = 0;
1473                 goto out_unlock;
1474         case IO_SCH_VERIFY:
1475                 /* Trigger path verification. */
1476                 io_subchannel_verify(sch);
1477                 rc = 0;
1478                 goto out_unlock;
1479         case IO_SCH_DISC:
1480                 ccw_device_set_disconnected(cdev);
1481                 rc = 0;
1482                 goto out_unlock;
1483         case IO_SCH_ORPH_UNREG:
1484         case IO_SCH_ORPH_ATTACH:
1485                 ccw_device_set_disconnected(cdev);
1486                 break;
1487         case IO_SCH_UNREG_ATTACH:
1488         case IO_SCH_UNREG:
1489                 if (!cdev)
1490                         break;
1491                 if (cdev->private->state == DEV_STATE_SENSE_ID) {
1492                         /*
1493                          * Note: delayed work triggered by this event
1494                          * and repeated calls to sch_event are synchronized
1495                          * by the above check for work_pending(cdev).
1496                          */
1497                         dev_fsm_event(cdev, DEV_EVENT_NOTOPER);
1498                 } else
1499                         ccw_device_set_notoper(cdev);
1500                 break;
1501         case IO_SCH_NOP:
1502                 rc = 0;
1503                 goto out_unlock;
1504         default:
1505                 break;
1506         }
1507         spin_unlock_irqrestore(sch->lock, flags);
1508         /* All other actions require process context. */
1509         if (!process)
1510                 goto out;
1511         /* Handle attached ccw device. */
1512         switch (action) {
1513         case IO_SCH_ORPH_UNREG:
1514         case IO_SCH_ORPH_ATTACH:
1515                 /* Move ccw device to orphanage. */
1516                 rc = ccw_device_move_to_orph(cdev);
1517                 if (rc)
1518                         goto out;
1519                 break;
1520         case IO_SCH_UNREG_ATTACH:
1521                 spin_lock_irqsave(sch->lock, flags);
1522                 sch_set_cdev(sch, NULL);
1523                 spin_unlock_irqrestore(sch->lock, flags);
1524                 /* Unregister ccw device. */
1525                 ccw_device_unregister(cdev);
1526                 break;
1527         default:
1528                 break;
1529         }
1530         /* Handle subchannel. */
1531         switch (action) {
1532         case IO_SCH_ORPH_UNREG:
1533         case IO_SCH_UNREG:
1534                 css_sch_device_unregister(sch);
1535                 break;
1536         case IO_SCH_ORPH_ATTACH:
1537         case IO_SCH_UNREG_ATTACH:
1538         case IO_SCH_ATTACH:
1539                 dev_id.ssid = sch->schid.ssid;
1540                 dev_id.devno = sch->schib.pmcw.dev;
1541                 cdev = get_ccwdev_by_dev_id(&dev_id);
1542                 if (!cdev) {
1543                         sch_create_and_recog_new_device(sch);
1544                         break;
1545                 }
1546                 rc = ccw_device_move_to_sch(cdev, sch);
1547                 if (rc) {
1548                         /* Release reference from get_ccwdev_by_dev_id() */
1549                         put_device(&cdev->dev);
1550                         goto out;
1551                 }
1552                 spin_lock_irqsave(sch->lock, flags);
1553                 ccw_device_trigger_reprobe(cdev);
1554                 spin_unlock_irqrestore(sch->lock, flags);
1555                 /* Release reference from get_ccwdev_by_dev_id() */
1556                 put_device(&cdev->dev);
1557                 break;
1558         default:
1559                 break;
1560         }
1561         return 0;
1562
1563 out_unlock:
1564         spin_unlock_irqrestore(sch->lock, flags);
1565 out:
1566         return rc;
1567 }
1568
1569 static void ccw_device_set_int_class(struct ccw_device *cdev)
1570 {
1571         struct ccw_driver *cdrv = cdev->drv;
1572
1573         /* Note: we interpret class 0 in this context as an uninitialized
1574          * field since it translates to a non-I/O interrupt class. */
1575         if (cdrv->int_class != 0)
1576                 cdev->private->int_class = cdrv->int_class;
1577         else
1578                 cdev->private->int_class = IRQIO_CIO;
1579 }
1580
1581 #ifdef CONFIG_CCW_CONSOLE
1582 int __init ccw_device_enable_console(struct ccw_device *cdev)
1583 {
1584         struct subchannel *sch = to_subchannel(cdev->dev.parent);
1585         int rc;
1586
1587         if (!cdev->drv || !cdev->handler)
1588                 return -EINVAL;
1589
1590         io_subchannel_init_fields(sch);
1591         rc = cio_commit_config(sch);
1592         if (rc)
1593                 return rc;
1594         sch->driver = &io_subchannel_driver;
1595         io_subchannel_recog(cdev, sch);
1596         /* Now wait for the async. recognition to come to an end. */
1597         spin_lock_irq(cdev->ccwlock);
1598         while (!dev_fsm_final_state(cdev))
1599                 ccw_device_wait_idle(cdev);
1600
1601         /* Hold on to an extra reference while device is online. */
1602         get_device(&cdev->dev);
1603         rc = ccw_device_online(cdev);
1604         if (rc)
1605                 goto out_unlock;
1606
1607         while (!dev_fsm_final_state(cdev))
1608                 ccw_device_wait_idle(cdev);
1609
1610         if (cdev->private->state == DEV_STATE_ONLINE)
1611                 cdev->online = 1;
1612         else
1613                 rc = -EIO;
1614 out_unlock:
1615         spin_unlock_irq(cdev->ccwlock);
1616         if (rc) /* Give up online reference since onlining failed. */
1617                 put_device(&cdev->dev);
1618         return rc;
1619 }
1620
1621 struct ccw_device * __init ccw_device_create_console(struct ccw_driver *drv)
1622 {
1623         struct io_subchannel_private *io_priv;
1624         struct ccw_device *cdev;
1625         struct subchannel *sch;
1626
1627         sch = cio_probe_console();
1628         if (IS_ERR(sch))
1629                 return ERR_CAST(sch);
1630
1631         io_priv = kzalloc(sizeof(*io_priv), GFP_KERNEL | GFP_DMA);
1632         if (!io_priv)
1633                 goto err_priv;
1634         io_priv->dma_area = dma_alloc_coherent(&sch->dev,
1635                                 sizeof(*io_priv->dma_area),
1636                                 &io_priv->dma_area_dma, GFP_KERNEL);
1637         if (!io_priv->dma_area)
1638                 goto err_dma_area;
1639         set_io_private(sch, io_priv);
1640         cdev = io_subchannel_create_ccwdev(sch);
1641         if (IS_ERR(cdev)) {
1642                 dma_free_coherent(&sch->dev, sizeof(*io_priv->dma_area),
1643                                   io_priv->dma_area, io_priv->dma_area_dma);
1644                 set_io_private(sch, NULL);
1645                 put_device(&sch->dev);
1646                 kfree(io_priv);
1647                 return cdev;
1648         }
1649         cdev->drv = drv;
1650         ccw_device_set_int_class(cdev);
1651         return cdev;
1652
1653 err_dma_area:
1654         kfree(io_priv);
1655 err_priv:
1656         put_device(&sch->dev);
1657         return ERR_PTR(-ENOMEM);
1658 }
1659
1660 void __init ccw_device_destroy_console(struct ccw_device *cdev)
1661 {
1662         struct subchannel *sch = to_subchannel(cdev->dev.parent);
1663         struct io_subchannel_private *io_priv = to_io_private(sch);
1664
1665         set_io_private(sch, NULL);
1666         dma_free_coherent(&sch->dev, sizeof(*io_priv->dma_area),
1667                           io_priv->dma_area, io_priv->dma_area_dma);
1668         put_device(&sch->dev);
1669         put_device(&cdev->dev);
1670         kfree(io_priv);
1671 }
1672
1673 /**
1674  * ccw_device_wait_idle() - busy wait for device to become idle
1675  * @cdev: ccw device
1676  *
1677  * Poll until activity control is zero, that is, no function or data
1678  * transfer is pending/active.
1679  * Called with device lock being held.
1680  */
1681 void ccw_device_wait_idle(struct ccw_device *cdev)
1682 {
1683         struct subchannel *sch = to_subchannel(cdev->dev.parent);
1684
1685         while (1) {
1686                 cio_tsch(sch);
1687                 if (sch->schib.scsw.cmd.actl == 0)
1688                         break;
1689                 udelay(100);
1690         }
1691 }
1692 #endif
1693
1694 /**
1695  * get_ccwdev_by_busid() - obtain device from a bus id
1696  * @cdrv: driver the device is owned by
1697  * @bus_id: bus id of the device to be searched
1698  *
1699  * This function searches all devices owned by @cdrv for a device with a bus
1700  * id matching @bus_id.
1701  * Returns:
1702  *  If a match is found, its reference count of the found device is increased
1703  *  and it is returned; else %NULL is returned.
1704  */
1705 struct ccw_device *get_ccwdev_by_busid(struct ccw_driver *cdrv,
1706                                        const char *bus_id)
1707 {
1708         struct device *dev;
1709
1710         dev = driver_find_device_by_name(&cdrv->driver, bus_id);
1711
1712         return dev ? to_ccwdev(dev) : NULL;
1713 }
1714
1715 /************************** device driver handling ************************/
1716
1717 /* This is the implementation of the ccw_driver class. The probe, remove
1718  * and release methods are initially very similar to the device_driver
1719  * implementations, with the difference that they have ccw_device
1720  * arguments.
1721  *
1722  * A ccw driver also contains the information that is needed for
1723  * device matching.
1724  */
1725 static int
1726 ccw_device_probe (struct device *dev)
1727 {
1728         struct ccw_device *cdev = to_ccwdev(dev);
1729         struct ccw_driver *cdrv = to_ccwdrv(dev->driver);
1730         int ret;
1731
1732         cdev->drv = cdrv; /* to let the driver call _set_online */
1733         ccw_device_set_int_class(cdev);
1734         ret = cdrv->probe ? cdrv->probe(cdev) : -ENODEV;
1735         if (ret) {
1736                 cdev->drv = NULL;
1737                 cdev->private->int_class = IRQIO_CIO;
1738                 return ret;
1739         }
1740
1741         return 0;
1742 }
1743
1744 static void ccw_device_remove(struct device *dev)
1745 {
1746         struct ccw_device *cdev = to_ccwdev(dev);
1747         struct ccw_driver *cdrv = cdev->drv;
1748         struct subchannel *sch;
1749         int ret;
1750
1751         if (cdrv->remove)
1752                 cdrv->remove(cdev);
1753
1754         spin_lock_irq(cdev->ccwlock);
1755         if (cdev->online) {
1756                 cdev->online = 0;
1757                 ret = ccw_device_offline(cdev);
1758                 spin_unlock_irq(cdev->ccwlock);
1759                 if (ret == 0)
1760                         wait_event(cdev->private->wait_q,
1761                                    dev_fsm_final_state(cdev));
1762                 else
1763                         CIO_MSG_EVENT(0, "ccw_device_offline returned %d, "
1764                                       "device 0.%x.%04x\n",
1765                                       ret, cdev->private->dev_id.ssid,
1766                                       cdev->private->dev_id.devno);
1767                 /* Give up reference obtained in ccw_device_set_online(). */
1768                 put_device(&cdev->dev);
1769                 spin_lock_irq(cdev->ccwlock);
1770         }
1771         ccw_device_set_timeout(cdev, 0);
1772         cdev->drv = NULL;
1773         cdev->private->int_class = IRQIO_CIO;
1774         sch = to_subchannel(cdev->dev.parent);
1775         spin_unlock_irq(cdev->ccwlock);
1776         io_subchannel_quiesce(sch);
1777         __disable_cmf(cdev);
1778 }
1779
1780 static void ccw_device_shutdown(struct device *dev)
1781 {
1782         struct ccw_device *cdev;
1783
1784         cdev = to_ccwdev(dev);
1785         if (cdev->drv && cdev->drv->shutdown)
1786                 cdev->drv->shutdown(cdev);
1787         __disable_cmf(cdev);
1788 }
1789
1790 static struct bus_type ccw_bus_type = {
1791         .name   = "ccw",
1792         .match  = ccw_bus_match,
1793         .uevent = ccw_uevent,
1794         .probe  = ccw_device_probe,
1795         .remove = ccw_device_remove,
1796         .shutdown = ccw_device_shutdown,
1797 };
1798
1799 /**
1800  * ccw_driver_register() - register a ccw driver
1801  * @cdriver: driver to be registered
1802  *
1803  * This function is mainly a wrapper around driver_register().
1804  * Returns:
1805  *   %0 on success and a negative error value on failure.
1806  */
1807 int ccw_driver_register(struct ccw_driver *cdriver)
1808 {
1809         struct device_driver *drv = &cdriver->driver;
1810
1811         drv->bus = &ccw_bus_type;
1812
1813         return driver_register(drv);
1814 }
1815
1816 /**
1817  * ccw_driver_unregister() - deregister a ccw driver
1818  * @cdriver: driver to be deregistered
1819  *
1820  * This function is mainly a wrapper around driver_unregister().
1821  */
1822 void ccw_driver_unregister(struct ccw_driver *cdriver)
1823 {
1824         driver_unregister(&cdriver->driver);
1825 }
1826
1827 static void ccw_device_todo(struct work_struct *work)
1828 {
1829         struct ccw_device_private *priv;
1830         struct ccw_device *cdev;
1831         struct subchannel *sch;
1832         enum cdev_todo todo;
1833
1834         priv = container_of(work, struct ccw_device_private, todo_work);
1835         cdev = priv->cdev;
1836         sch = to_subchannel(cdev->dev.parent);
1837         /* Find out todo. */
1838         spin_lock_irq(cdev->ccwlock);
1839         todo = priv->todo;
1840         priv->todo = CDEV_TODO_NOTHING;
1841         CIO_MSG_EVENT(4, "cdev_todo: cdev=0.%x.%04x todo=%d\n",
1842                       priv->dev_id.ssid, priv->dev_id.devno, todo);
1843         spin_unlock_irq(cdev->ccwlock);
1844         /* Perform todo. */
1845         switch (todo) {
1846         case CDEV_TODO_ENABLE_CMF:
1847                 cmf_reenable(cdev);
1848                 break;
1849         case CDEV_TODO_REBIND:
1850                 ccw_device_do_unbind_bind(cdev);
1851                 break;
1852         case CDEV_TODO_REGISTER:
1853                 io_subchannel_register(cdev);
1854                 break;
1855         case CDEV_TODO_UNREG_EVAL:
1856                 if (!sch_is_pseudo_sch(sch))
1857                         css_schedule_eval(sch->schid);
1858                 fallthrough;
1859         case CDEV_TODO_UNREG:
1860                 if (sch_is_pseudo_sch(sch))
1861                         ccw_device_unregister(cdev);
1862                 else
1863                         ccw_device_call_sch_unregister(cdev);
1864                 break;
1865         default:
1866                 break;
1867         }
1868         /* Release workqueue ref. */
1869         put_device(&cdev->dev);
1870 }
1871
1872 /**
1873  * ccw_device_sched_todo - schedule ccw device operation
1874  * @cdev: ccw device
1875  * @todo: todo
1876  *
1877  * Schedule the operation identified by @todo to be performed on the slow path
1878  * workqueue. Do nothing if another operation with higher priority is already
1879  * scheduled. Needs to be called with ccwdev lock held.
1880  */
1881 void ccw_device_sched_todo(struct ccw_device *cdev, enum cdev_todo todo)
1882 {
1883         CIO_MSG_EVENT(4, "cdev_todo: sched cdev=0.%x.%04x todo=%d\n",
1884                       cdev->private->dev_id.ssid, cdev->private->dev_id.devno,
1885                       todo);
1886         if (cdev->private->todo >= todo)
1887                 return;
1888         cdev->private->todo = todo;
1889         /* Get workqueue ref. */
1890         if (!get_device(&cdev->dev))
1891                 return;
1892         if (!queue_work(cio_work_q, &cdev->private->todo_work)) {
1893                 /* Already queued, release workqueue ref. */
1894                 put_device(&cdev->dev);
1895         }
1896 }
1897
1898 /**
1899  * ccw_device_siosl() - initiate logging
1900  * @cdev: ccw device
1901  *
1902  * This function is used to invoke model-dependent logging within the channel
1903  * subsystem.
1904  */
1905 int ccw_device_siosl(struct ccw_device *cdev)
1906 {
1907         struct subchannel *sch = to_subchannel(cdev->dev.parent);
1908
1909         return chsc_siosl(sch->schid);
1910 }
1911 EXPORT_SYMBOL_GPL(ccw_device_siosl);
1912
1913 EXPORT_SYMBOL(ccw_device_set_online);
1914 EXPORT_SYMBOL(ccw_device_set_offline);
1915 EXPORT_SYMBOL(ccw_driver_register);
1916 EXPORT_SYMBOL(ccw_driver_unregister);
1917 EXPORT_SYMBOL(get_ccwdev_by_busid);