drivers/s390/cio/chp.c

   1 /*
   2  *  drivers/s390/cio/chp.c
   3  *
   4  *    Copyright IBM Corp. 1999,2007
   5  *    Author(s): Cornelia Huck (cornelia.huck@de.ibm.com)
   6  *               Arnd Bergmann (arndb@de.ibm.com)
   7  *               Peter Oberparleiter <peter.oberparleiter@de.ibm.com>
   8  */
   9
  10 #include <linux/bug.h>
  11 #include <linux/workqueue.h>
  12 #include <linux/spinlock.h>
  13 #include <linux/init.h>
  14 #include <linux/jiffies.h>
  15 #include <linux/wait.h>
  16 #include <linux/mutex.h>
  17 #include <linux/errno.h>
  18 #include <asm/chpid.h>
  19 #include <asm/sclp.h>
  20 #include <asm/crw.h>
  21
  22 #include "cio.h"
  23 #include "css.h"
  24 #include "ioasm.h"
  25 #include "cio_debug.h"
  26 #include "chp.h"
  27
  28 #define to_channelpath(device) container_of(device, struct channel_path, dev)
  29 #define CHP_INFO_UPDATE_INTERVAL        1*HZ
  30
  31 enum cfg_task_t {
  32         cfg_none,
  33         cfg_configure,
  34         cfg_deconfigure
  35 };
  36
  37 /* Map for pending configure tasks. */
  38 static enum cfg_task_t chp_cfg_task[__MAX_CSSID + 1][__MAX_CHPID + 1];
  39 static DEFINE_MUTEX(cfg_lock);
  40 static int cfg_busy;
  41
  42 /* Map for channel-path status. */
  43 static struct sclp_chp_info chp_info;
  44 static DEFINE_MUTEX(info_lock);
  45
  46 /* Time after which channel-path status may be outdated. */
  47 static unsigned long chp_info_expires;
  48
  49 /* Workqueue to perform pending configure tasks. */
  50 static struct workqueue_struct *chp_wq;
  51 static struct work_struct cfg_work;
  52
  53 /* Wait queue for configure completion events. */
  54 static wait_queue_head_t cfg_wait_queue;
  55
  56 /* Return channel_path struct for given chpid. */
  57 static inline struct channel_path *chpid_to_chp(struct chp_id chpid)
  58 {
  59         return channel_subsystems[chpid.cssid]->chps[chpid.id];
  60 }
  61
  62 /* Set vary state for given chpid. */
  63 static void set_chp_logically_online(struct chp_id chpid, int onoff)
  64 {
  65         chpid_to_chp(chpid)->state = onoff;
  66 }
  67
  68 /* On succes return 0 if channel-path is varied offline, 1 if it is varied
  69  * online. Return -ENODEV if channel-path is not registered. */
  70 int chp_get_status(struct chp_id chpid)
  71 {
  72         return (chpid_to_chp(chpid) ? chpid_to_chp(chpid)->state : -ENODEV);
  73 }
  74
  75 /**
  76  * chp_get_sch_opm - return opm for subchannel
  77  * @sch: subchannel
  78  *
  79  * Calculate and return the operational path mask (opm) based on the chpids
  80  * used by the subchannel and the status of the associated channel-paths.
  81  */
  82 u8 chp_get_sch_opm(struct subchannel *sch)
  83 {
  84         struct chp_id chpid;
  85         int opm;
  86         int i;
  87
  88         opm = 0;
  89         chp_id_init(&chpid);
  90         for (i = 0; i < 8; i++) {
  91                 opm <<= 1;
  92                 chpid.id = sch->schib.pmcw.chpid[i];
  93                 if (chp_get_status(chpid) != 0)
  94                         opm |= 1;
  95         }
  96         return opm;
  97 }
  98 EXPORT_SYMBOL_GPL(chp_get_sch_opm);
  99
 100 /**
 101  * chp_is_registered - check if a channel-path is registered
 102  * @chpid: channel-path ID
 103  *
 104  * Return non-zero if a channel-path with the given chpid is registered,
 105  * zero otherwise.
 106  */
 107 int chp_is_registered(struct chp_id chpid)
 108 {
 109         return chpid_to_chp(chpid) != NULL;
 110 }
 111
 112 /*
 113  * Function: s390_vary_chpid
 114  * Varies the specified chpid online or offline
 115  */
 116 static int s390_vary_chpid(struct chp_id chpid, int on)
 117 {
 118         char dbf_text[15];
 119         int status;
 120
 121         sprintf(dbf_text, on?"varyon%x.%02x":"varyoff%x.%02x", chpid.cssid,
 122                 chpid.id);
 123         CIO_TRACE_EVENT(2, dbf_text);
 124
 125         status = chp_get_status(chpid);
 126         if (!on && !status)
 127                 return 0;
 128
 129         set_chp_logically_online(chpid, on);
 130         chsc_chp_vary(chpid, on);
 131         return 0;
 132 }
 133
 134 /*
 135  * Channel measurement related functions
 136  */
 137 static ssize_t chp_measurement_chars_read(struct kobject *kobj,
 138                                           struct bin_attribute *bin_attr,
 139                                           char *buf, loff_t off, size_t count)
 140 {
 141         struct channel_path *chp;
 142         struct device *device;
 143
 144         device = container_of(kobj, struct device, kobj);
 145         chp = to_channelpath(device);
 146         if (!chp->cmg_chars)
 147                 return 0;
 148
 149         return memory_read_from_buffer(buf, count, &off,
 150                                 chp->cmg_chars, sizeof(struct cmg_chars));
 151 }
 152
 153 static struct bin_attribute chp_measurement_chars_attr = {
 154         .attr = {
 155                 .name = "measurement_chars",
 156                 .mode = S_IRUSR,
 157         },
 158         .size = sizeof(struct cmg_chars),
 159         .read = chp_measurement_chars_read,
 160 };
 161
 162 static void chp_measurement_copy_block(struct cmg_entry *buf,
 163                                        struct channel_subsystem *css,
 164                                        struct chp_id chpid)
 165 {
 166         void *area;
 167         struct cmg_entry *entry, reference_buf;
 168         int idx;
 169
 170         if (chpid.id < 128) {
 171                 area = css->cub_addr1;
 172                 idx = chpid.id;
 173         } else {
 174                 area = css->cub_addr2;
 175                 idx = chpid.id - 128;
 176         }
 177         entry = area + (idx * sizeof(struct cmg_entry));
 178         do {
 179                 memcpy(buf, entry, sizeof(*entry));
 180                 memcpy(&reference_buf, entry, sizeof(*entry));
 181         } while (reference_buf.values[0] != buf->values[0]);
 182 }
 183
 184 static ssize_t chp_measurement_read(struct kobject *kobj,
 185                                     struct bin_attribute *bin_attr,
 186                                     char *buf, loff_t off, size_t count)
 187 {
 188         struct channel_path *chp;
 189         struct channel_subsystem *css;
 190         struct device *device;
 191         unsigned int size;
 192
 193         device = container_of(kobj, struct device, kobj);
 194         chp = to_channelpath(device);
 195         css = to_css(chp->dev.parent);
 196
 197         size = sizeof(struct cmg_entry);
 198
 199         /* Only allow single reads. */
 200         if (off || count < size)
 201                 return 0;
 202         chp_measurement_copy_block((struct cmg_entry *)buf, css, chp->chpid);
 203         count = size;
 204         return count;
 205 }
 206
 207 static struct bin_attribute chp_measurement_attr = {
 208         .attr = {
 209                 .name = "measurement",
 210                 .mode = S_IRUSR,
 211         },
 212         .size = sizeof(struct cmg_entry),
 213         .read = chp_measurement_read,
 214 };
 215
 216 void chp_remove_cmg_attr(struct channel_path *chp)
 217 {
 218         device_remove_bin_file(&chp->dev, &chp_measurement_chars_attr);
 219         device_remove_bin_file(&chp->dev, &chp_measurement_attr);
 220 }
 221
 222 int chp_add_cmg_attr(struct channel_path *chp)
 223 {
 224         int ret;
 225
 226         ret = device_create_bin_file(&chp->dev, &chp_measurement_chars_attr);
 227         if (ret)
 228                 return ret;
 229         ret = device_create_bin_file(&chp->dev, &chp_measurement_attr);
 230         if (ret)
 231                 device_remove_bin_file(&chp->dev, &chp_measurement_chars_attr);
 232         return ret;
 233 }
 234
 235 /*
 236  * Files for the channel path entries.
 237  */
 238 static ssize_t chp_status_show(struct device *dev,
 239                                struct device_attribute *attr, char *buf)
 240 {
 241         struct channel_path *chp = to_channelpath(dev);
 242
 243         if (!chp)
 244                 return 0;
 245         return (chp_get_status(chp->chpid) ? sprintf(buf, "online\n") :
 246                 sprintf(buf, "offline\n"));
 247 }
 248
 249 static ssize_t chp_status_write(struct device *dev,
 250                                 struct device_attribute *attr,
 251                                 const char *buf, size_t count)
 252 {
 253         struct channel_path *cp = to_channelpath(dev);
 254         char cmd[10];
 255         int num_args;
 256         int error;
 257
 258         num_args = sscanf(buf, "%5s", cmd);
 259         if (!num_args)
 260                 return count;
 261
 262         if (!strnicmp(cmd, "on", 2) || !strcmp(cmd, "1"))
 263                 error = s390_vary_chpid(cp->chpid, 1);
 264         else if (!strnicmp(cmd, "off", 3) || !strcmp(cmd, "0"))
 265                 error = s390_vary_chpid(cp->chpid, 0);
 266         else
 267                 error = -EINVAL;
 268
 269         return error < 0 ? error : count;
 270
 271 }
 272
 273 static DEVICE_ATTR(status, 0644, chp_status_show, chp_status_write);
 274
 275 static ssize_t chp_configure_show(struct device *dev,
 276                                   struct device_attribute *attr, char *buf)
 277 {
 278         struct channel_path *cp;
 279         int status;
 280
 281         cp = to_channelpath(dev);
 282         status = chp_info_get_status(cp->chpid);
 283         if (status < 0)
 284                 return status;
 285
 286         return snprintf(buf, PAGE_SIZE, "%d\n", status);
 287 }
 288
 289 static int cfg_wait_idle(void);
 290
 291 static ssize_t chp_configure_write(struct device *dev,
 292                                    struct device_attribute *attr,
 293                                    const char *buf, size_t count)
 294 {
 295         struct channel_path *cp;
 296         int val;
 297         char delim;
 298
 299         if (sscanf(buf, "%d %c", &val, &delim) != 1)
 300                 return -EINVAL;
 301         if (val != 0 && val != 1)
 302                 return -EINVAL;
 303         cp = to_channelpath(dev);
 304         chp_cfg_schedule(cp->chpid, val);
 305         cfg_wait_idle();
 306
 307         return count;
 308 }
 309
 310 static DEVICE_ATTR(configure, 0644, chp_configure_show, chp_configure_write);
 311
 312 static ssize_t chp_type_show(struct device *dev, struct device_attribute *attr,
 313                              char *buf)
 314 {
 315         struct channel_path *chp = to_channelpath(dev);
 316
 317         if (!chp)
 318                 return 0;
 319         return sprintf(buf, "%x\n", chp->desc.desc);
 320 }
 321
 322 static DEVICE_ATTR(type, 0444, chp_type_show, NULL);
 323
 324 static ssize_t chp_cmg_show(struct device *dev, struct device_attribute *attr,
 325                             char *buf)
 326 {
 327         struct channel_path *chp = to_channelpath(dev);
 328
 329         if (!chp)
 330                 return 0;
 331         if (chp->cmg == -1) /* channel measurements not available */
 332                 return sprintf(buf, "unknown\n");
 333         return sprintf(buf, "%x\n", chp->cmg);
 334 }
 335
 336 static DEVICE_ATTR(cmg, 0444, chp_cmg_show, NULL);
 337
 338 static ssize_t chp_shared_show(struct device *dev,
 339                                struct device_attribute *attr, char *buf)
 340 {
 341         struct channel_path *chp = to_channelpath(dev);
 342
 343         if (!chp)
 344                 return 0;
 345         if (chp->shared == -1) /* channel measurements not available */
 346                 return sprintf(buf, "unknown\n");
 347         return sprintf(buf, "%x\n", chp->shared);
 348 }
 349
 350 static DEVICE_ATTR(shared, 0444, chp_shared_show, NULL);
 351
 352 static struct attribute *chp_attrs[] = {
 353         &dev_attr_status.attr,
 354         &dev_attr_configure.attr,
 355         &dev_attr_type.attr,
 356         &dev_attr_cmg.attr,
 357         &dev_attr_shared.attr,
 358         NULL,
 359 };
 360
 361 static struct attribute_group chp_attr_group = {
 362         .attrs = chp_attrs,
 363 };
 364
 365 static void chp_release(struct device *dev)
 366 {
 367         struct channel_path *cp;
 368
 369         cp = to_channelpath(dev);
 370         kfree(cp);
 371 }
 372
 373 /**
 374  * chp_new - register a new channel-path
 375  * @chpid - channel-path ID
 376  *
 377  * Create and register data structure representing new channel-path. Return
 378  * zero on success, non-zero otherwise.
 379  */
 380 int chp_new(struct chp_id chpid)
 381 {
 382         struct channel_path *chp;
 383         int ret;
 384
 385         if (chp_is_registered(chpid))
 386                 return 0;
 387         chp = kzalloc(sizeof(struct channel_path), GFP_KERNEL);
 388         if (!chp)
 389                 return -ENOMEM;
 390
 391         /* fill in status, etc. */
 392         chp->chpid = chpid;
 393         chp->state = 1;
 394         chp->dev.parent = &channel_subsystems[chpid.cssid]->device;
 395         chp->dev.release = chp_release;
 396         dev_set_name(&chp->dev, "chp%x.%02x", chpid.cssid, chpid.id);
 397
 398         /* Obtain channel path description and fill it in. */
 399         ret = chsc_determine_base_channel_path_desc(chpid, &chp->desc);
 400         if (ret)
 401                 goto out_free;
 402         if ((chp->desc.flags & 0x80) == 0) {
 403                 ret = -ENODEV;
 404                 goto out_free;
 405         }
 406         /* Get channel-measurement characteristics. */
 407         if (css_chsc_characteristics.scmc && css_chsc_characteristics.secm) {
 408                 ret = chsc_get_channel_measurement_chars(chp);
 409                 if (ret)
 410                         goto out_free;
 411         } else {
 412                 chp->cmg = -1;
 413         }
 414
 415         /* make it known to the system */
 416         ret = device_register(&chp->dev);
 417         if (ret) {
 418                 CIO_MSG_EVENT(0, "Could not register chp%x.%02x: %d\n",
 419                               chpid.cssid, chpid.id, ret);
 420                 goto out_free;
 421         }
 422         ret = sysfs_create_group(&chp->dev.kobj, &chp_attr_group);
 423         if (ret) {
 424                 device_unregister(&chp->dev);
 425                 goto out;
 426         }
 427         mutex_lock(&channel_subsystems[chpid.cssid]->mutex);
 428         if (channel_subsystems[chpid.cssid]->cm_enabled) {
 429                 ret = chp_add_cmg_attr(chp);
 430                 if (ret) {
 431                         sysfs_remove_group(&chp->dev.kobj, &chp_attr_group);
 432                         device_unregister(&chp->dev);
 433                         mutex_unlock(&channel_subsystems[chpid.cssid]->mutex);
 434                         goto out;
 435                 }
 436         }
 437         channel_subsystems[chpid.cssid]->chps[chpid.id] = chp;
 438         mutex_unlock(&channel_subsystems[chpid.cssid]->mutex);
 439         goto out;
 440 out_free:
 441         kfree(chp);
 442 out:
 443         return ret;
 444 }
 445
 446 /**
 447  * chp_get_chp_desc - return newly allocated channel-path description
 448  * @chpid: channel-path ID
 449  *
 450  * On success return a newly allocated copy of the channel-path description
 451  * data associated with the given channel-path ID. Return %NULL on error.
 452  */
 453 void *chp_get_chp_desc(struct chp_id chpid)
 454 {
 455         struct channel_path *chp;
 456         struct channel_path_desc *desc;
 457
 458         chp = chpid_to_chp(chpid);
 459         if (!chp)
 460                 return NULL;
 461         desc = kmalloc(sizeof(struct channel_path_desc), GFP_KERNEL);
 462         if (!desc)
 463                 return NULL;
 464         memcpy(desc, &chp->desc, sizeof(struct channel_path_desc));
 465         return desc;
 466 }
 467
 468 /**
 469  * chp_process_crw - process channel-path status change
 470  * @crw0: channel report-word to handler
 471  * @crw1: second channel-report word (always NULL)
 472  * @overflow: crw overflow indication
 473  *
 474  * Handle channel-report-words indicating that the status of a channel-path
 475  * has changed.
 476  */
 477 static void chp_process_crw(struct crw *crw0, struct crw *crw1,
 478                             int overflow)
 479 {
 480         struct chp_id chpid;
 481
 482         if (overflow) {
 483                 css_schedule_eval_all();
 484                 return;
 485         }
 486         CIO_CRW_EVENT(2, "CRW reports slct=%d, oflw=%d, "
 487                       "chn=%d, rsc=%X, anc=%d, erc=%X, rsid=%X\n",
 488                       crw0->slct, crw0->oflw, crw0->chn, crw0->rsc, crw0->anc,
 489                       crw0->erc, crw0->rsid);
 490         /*
 491          * Check for solicited machine checks. These are
 492          * created by reset channel path and need not be
 493          * handled here.
 494          */
 495         if (crw0->slct) {
 496                 CIO_CRW_EVENT(2, "solicited machine check for "
 497                               "channel path %02X\n", crw0->rsid);
 498                 return;
 499         }
 500         chp_id_init(&chpid);
 501         chpid.id = crw0->rsid;
 502         switch (crw0->erc) {
 503         case CRW_ERC_IPARM: /* Path has come. */
 504                 if (!chp_is_registered(chpid))
 505                         chp_new(chpid);
 506                 chsc_chp_online(chpid);
 507                 break;
 508         case CRW_ERC_PERRI: /* Path has gone. */
 509         case CRW_ERC_PERRN:
 510                 chsc_chp_offline(chpid);
 511                 break;
 512         default:
 513                 CIO_CRW_EVENT(2, "Don't know how to handle erc=%x\n",
 514                               crw0->erc);
 515         }
 516 }
 517
 518 int chp_ssd_get_mask(struct chsc_ssd_info *ssd, struct chp_link *link)
 519 {
 520         int i;
 521         int mask;
 522
 523         for (i = 0; i < 8; i++) {
 524                 mask = 0x80 >> i;
 525                 if (!(ssd->path_mask & mask))
 526                         continue;
 527                 if (!chp_id_is_equal(&ssd->chpid[i], &link->chpid))
 528                         continue;
 529                 if ((ssd->fla_valid_mask & mask) &&
 530                     ((ssd->fla[i] & link->fla_mask) != link->fla))
 531                         continue;
 532                 return mask;
 533         }
 534         return 0;
 535 }
 536 EXPORT_SYMBOL_GPL(chp_ssd_get_mask);
 537
 538 static inline int info_bit_num(struct chp_id id)
 539 {
 540         return id.id + id.cssid * (__MAX_CHPID + 1);
 541 }
 542
 543 /* Force chp_info refresh on next call to info_validate(). */
 544 static void info_expire(void)
 545 {
 546         mutex_lock(&info_lock);
 547         chp_info_expires = jiffies - 1;
 548         mutex_unlock(&info_lock);
 549 }
 550
 551 /* Ensure that chp_info is up-to-date. */
 552 static int info_update(void)
 553 {
 554         int rc;
 555
 556         mutex_lock(&info_lock);
 557         rc = 0;
 558         if (time_after(jiffies, chp_info_expires)) {
 559                 /* Data is too old, update. */
 560                 rc = sclp_chp_read_info(&chp_info);
 561                 chp_info_expires = jiffies + CHP_INFO_UPDATE_INTERVAL ;
 562         }
 563         mutex_unlock(&info_lock);
 564
 565         return rc;
 566 }
 567
 568 /**
 569  * chp_info_get_status - retrieve configure status of a channel-path
 570  * @chpid: channel-path ID
 571  *
 572  * On success, return 0 for standby, 1 for configured, 2 for reserved,
 573  * 3 for not recognized. Return negative error code on error.
 574  */
 575 int chp_info_get_status(struct chp_id chpid)
 576 {
 577         int rc;
 578         int bit;
 579
 580         rc = info_update();
 581         if (rc)
 582                 return rc;
 583
 584         bit = info_bit_num(chpid);
 585         mutex_lock(&info_lock);
 586         if (!chp_test_bit(chp_info.recognized, bit))
 587                 rc = CHP_STATUS_NOT_RECOGNIZED;
 588         else if (chp_test_bit(chp_info.configured, bit))
 589                 rc = CHP_STATUS_CONFIGURED;
 590         else if (chp_test_bit(chp_info.standby, bit))
 591                 rc = CHP_STATUS_STANDBY;
 592         else
 593                 rc = CHP_STATUS_RESERVED;
 594         mutex_unlock(&info_lock);
 595
 596         return rc;
 597 }
 598
 599 /* Return configure task for chpid. */
 600 static enum cfg_task_t cfg_get_task(struct chp_id chpid)
 601 {
 602         return chp_cfg_task[chpid.cssid][chpid.id];
 603 }
 604
 605 /* Set configure task for chpid. */
 606 static void cfg_set_task(struct chp_id chpid, enum cfg_task_t cfg)
 607 {
 608         chp_cfg_task[chpid.cssid][chpid.id] = cfg;
 609 }
 610
 611 /* Perform one configure/deconfigure request. Reschedule work function until
 612  * last request. */
 613 static void cfg_func(struct work_struct *work)
 614 {
 615         struct chp_id chpid;
 616         enum cfg_task_t t;
 617         int rc;
 618
 619         mutex_lock(&cfg_lock);
 620         t = cfg_none;
 621         chp_id_for_each(&chpid) {
 622                 t = cfg_get_task(chpid);
 623                 if (t != cfg_none) {
 624                         cfg_set_task(chpid, cfg_none);
 625                         break;
 626                 }
 627         }
 628         mutex_unlock(&cfg_lock);
 629
 630         switch (t) {
 631         case cfg_configure:
 632                 rc = sclp_chp_configure(chpid);
 633                 if (rc)
 634                         CIO_MSG_EVENT(2, "chp: sclp_chp_configure(%x.%02x)="
 635                                       "%d\n", chpid.cssid, chpid.id, rc);
 636                 else {
 637                         info_expire();
 638                         chsc_chp_online(chpid);
 639                 }
 640                 break;
 641         case cfg_deconfigure:
 642                 rc = sclp_chp_deconfigure(chpid);
 643                 if (rc)
 644                         CIO_MSG_EVENT(2, "chp: sclp_chp_deconfigure(%x.%02x)="
 645                                       "%d\n", chpid.cssid, chpid.id, rc);
 646                 else {
 647                         info_expire();
 648                         chsc_chp_offline(chpid);
 649                 }
 650                 break;
 651         case cfg_none:
 652                 /* Get updated information after last change. */
 653                 info_update();
 654                 mutex_lock(&cfg_lock);
 655                 cfg_busy = 0;
 656                 mutex_unlock(&cfg_lock);
 657                 wake_up_interruptible(&cfg_wait_queue);
 658                 return;
 659         }
 660         queue_work(chp_wq, &cfg_work);
 661 }
 662
 663 /**
 664  * chp_cfg_schedule - schedule chpid configuration request
 665  * @chpid - channel-path ID
 666  * @configure - Non-zero for configure, zero for deconfigure
 667  *
 668  * Schedule a channel-path configuration/deconfiguration request.
 669  */
 670 void chp_cfg_schedule(struct chp_id chpid, int configure)
 671 {
 672         CIO_MSG_EVENT(2, "chp_cfg_sched%x.%02x=%d\n", chpid.cssid, chpid.id,
 673                       configure);
 674         mutex_lock(&cfg_lock);
 675         cfg_set_task(chpid, configure ? cfg_configure : cfg_deconfigure);
 676         cfg_busy = 1;
 677         mutex_unlock(&cfg_lock);
 678         queue_work(chp_wq, &cfg_work);
 679 }
 680
 681 /**
 682  * chp_cfg_cancel_deconfigure - cancel chpid deconfiguration request
 683  * @chpid - channel-path ID
 684  *
 685  * Cancel an active channel-path deconfiguration request if it has not yet
 686  * been performed.
 687  */
 688 void chp_cfg_cancel_deconfigure(struct chp_id chpid)
 689 {
 690         CIO_MSG_EVENT(2, "chp_cfg_cancel:%x.%02x\n", chpid.cssid, chpid.id);
 691         mutex_lock(&cfg_lock);
 692         if (cfg_get_task(chpid) == cfg_deconfigure)
 693                 cfg_set_task(chpid, cfg_none);
 694         mutex_unlock(&cfg_lock);
 695 }
 696
 697 static int cfg_wait_idle(void)
 698 {
 699         if (wait_event_interruptible(cfg_wait_queue, !cfg_busy))
 700                 return -ERESTARTSYS;
 701         return 0;
 702 }
 703
 704 static int __init chp_init(void)
 705 {
 706         struct chp_id chpid;
 707         int ret;
 708
 709         ret = crw_register_handler(CRW_RSC_CPATH, chp_process_crw);
 710         if (ret)
 711                 return ret;
 712         chp_wq = create_singlethread_workqueue("cio_chp");
 713         if (!chp_wq) {
 714                 crw_unregister_handler(CRW_RSC_CPATH);
 715                 return -ENOMEM;
 716         }
 717         INIT_WORK(&cfg_work, cfg_func);
 718         init_waitqueue_head(&cfg_wait_queue);
 719         if (info_update())
 720                 return 0;
 721         /* Register available channel-paths. */
 722         chp_id_for_each(&chpid) {
 723                 if (chp_info_get_status(chpid) != CHP_STATUS_NOT_RECOGNIZED)
 724                         chp_new(chpid);
 725         }
 726
 727         return 0;
 728 }
 729
 730 subsys_initcall(chp_init);