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