drivers/s390/cio/css.c

   1 /*
   2  *  drivers/s390/cio/css.c
   3  *  driver for channel subsystem
   4  *
   5  *    Copyright (C) 2002 IBM Deutschland Entwicklung GmbH,
   6  *                       IBM Corporation
   7  *    Author(s): Arnd Bergmann (arndb@de.ibm.com)
   8  *               Cornelia Huck (cornelia.huck@de.ibm.com)
   9  */
  10 #include <linux/module.h>
  11 #include <linux/init.h>
  12 #include <linux/device.h>
  13 #include <linux/slab.h>
  14 #include <linux/errno.h>
  15 #include <linux/list.h>
  16 #include <linux/reboot.h>
  17
  18 #include "css.h"
  19 #include "cio.h"
  20 #include "cio_debug.h"
  21 #include "ioasm.h"
  22 #include "chsc.h"
  23 #include "device.h"
  24 #include "idset.h"
  25 #include "chp.h"
  26
  27 int css_init_done = 0;
  28 static int need_reprobe = 0;
  29 static int max_ssid = 0;
  30
  31 struct channel_subsystem *channel_subsystems[__MAX_CSSID + 1];
  32
  33 int css_characteristics_avail = 0;
  34
  35 int
  36 for_each_subchannel(int(*fn)(struct subchannel_id, void *), void *data)
  37 {
  38         struct subchannel_id schid;
  39         int ret;
  40
  41         init_subchannel_id(&schid);
  42         ret = -ENODEV;
  43         do {
  44                 do {
  45                         ret = fn(schid, data);
  46                         if (ret)
  47                                 break;
  48                 } while (schid.sch_no++ < __MAX_SUBCHANNEL);
  49                 schid.sch_no = 0;
  50         } while (schid.ssid++ < max_ssid);
  51         return ret;
  52 }
  53
  54 static struct subchannel *
  55 css_alloc_subchannel(struct subchannel_id schid)
  56 {
  57         struct subchannel *sch;
  58         int ret;
  59
  60         sch = kmalloc (sizeof (*sch), GFP_KERNEL | GFP_DMA);
  61         if (sch == NULL)
  62                 return ERR_PTR(-ENOMEM);
  63         ret = cio_validate_subchannel (sch, schid);
  64         if (ret < 0) {
  65                 kfree(sch);
  66                 return ERR_PTR(ret);
  67         }
  68
  69         if (sch->st != SUBCHANNEL_TYPE_IO) {
  70                 /* For now we ignore all non-io subchannels. */
  71                 kfree(sch);
  72                 return ERR_PTR(-EINVAL);
  73         }
  74
  75         /*
  76          * Set intparm to subchannel address.
  77          * This is fine even on 64bit since the subchannel is always located
  78          * under 2G.
  79          */
  80         sch->schib.pmcw.intparm = (__u32)(unsigned long)sch;
  81         ret = cio_modify(sch);
  82         if (ret) {
  83                 kfree(sch->lock);
  84                 kfree(sch);
  85                 return ERR_PTR(ret);
  86         }
  87         return sch;
  88 }
  89
  90 static void
  91 css_free_subchannel(struct subchannel *sch)
  92 {
  93         if (sch) {
  94                 /* Reset intparm to zeroes. */
  95                 sch->schib.pmcw.intparm = 0;
  96                 cio_modify(sch);
  97                 kfree(sch->lock);
  98                 kfree(sch);
  99         }
 100 }
 101
 102 static void
 103 css_subchannel_release(struct device *dev)
 104 {
 105         struct subchannel *sch;
 106
 107         sch = to_subchannel(dev);
 108         if (!cio_is_console(sch->schid)) {
 109                 kfree(sch->lock);
 110                 kfree(sch);
 111         }
 112 }
 113
 114 static int css_sch_device_register(struct subchannel *sch)
 115 {
 116         int ret;
 117
 118         mutex_lock(&sch->reg_mutex);
 119         ret = device_register(&sch->dev);
 120         mutex_unlock(&sch->reg_mutex);
 121         return ret;
 122 }
 123
 124 void css_sch_device_unregister(struct subchannel *sch)
 125 {
 126         mutex_lock(&sch->reg_mutex);
 127         device_unregister(&sch->dev);
 128         mutex_unlock(&sch->reg_mutex);
 129 }
 130
 131 static void ssd_from_pmcw(struct chsc_ssd_info *ssd, struct pmcw *pmcw)
 132 {
 133         int i;
 134         int mask;
 135
 136         memset(ssd, 0, sizeof(struct chsc_ssd_info));
 137         ssd->path_mask = pmcw->pim;
 138         for (i = 0; i < 8; i++) {
 139                 mask = 0x80 >> i;
 140                 if (pmcw->pim & mask) {
 141                         chp_id_init(&ssd->chpid[i]);
 142                         ssd->chpid[i].id = pmcw->chpid[i];
 143                 }
 144         }
 145 }
 146
 147 static void ssd_register_chpids(struct chsc_ssd_info *ssd)
 148 {
 149         int i;
 150         int mask;
 151
 152         for (i = 0; i < 8; i++) {
 153                 mask = 0x80 >> i;
 154                 if (ssd->path_mask & mask)
 155                         if (!chp_is_registered(ssd->chpid[i]))
 156                                 chp_new(ssd->chpid[i]);
 157         }
 158 }
 159
 160 void css_update_ssd_info(struct subchannel *sch)
 161 {
 162         int ret;
 163
 164         if (cio_is_console(sch->schid)) {
 165                 /* Console is initialized too early for functions requiring
 166                  * memory allocation. */
 167                 ssd_from_pmcw(&sch->ssd_info, &sch->schib.pmcw);
 168         } else {
 169                 ret = chsc_get_ssd_info(sch->schid, &sch->ssd_info);
 170                 if (ret)
 171                         ssd_from_pmcw(&sch->ssd_info, &sch->schib.pmcw);
 172                 ssd_register_chpids(&sch->ssd_info);
 173         }
 174 }
 175
 176 static int css_register_subchannel(struct subchannel *sch)
 177 {
 178         int ret;
 179
 180         /* Initialize the subchannel structure */
 181         sch->dev.parent = &channel_subsystems[0]->device;
 182         sch->dev.bus = &css_bus_type;
 183         sch->dev.release = &css_subchannel_release;
 184         sch->dev.groups = subch_attr_groups;
 185         css_update_ssd_info(sch);
 186         /* make it known to the system */
 187         ret = css_sch_device_register(sch);
 188         if (ret) {
 189                 CIO_MSG_EVENT(0, "Could not register sch 0.%x.%04x: %d\n",
 190                               sch->schid.ssid, sch->schid.sch_no, ret);
 191                 return ret;
 192         }
 193         return ret;
 194 }
 195
 196 static int css_probe_device(struct subchannel_id schid)
 197 {
 198         int ret;
 199         struct subchannel *sch;
 200
 201         sch = css_alloc_subchannel(schid);
 202         if (IS_ERR(sch))
 203                 return PTR_ERR(sch);
 204         ret = css_register_subchannel(sch);
 205         if (ret)
 206                 css_free_subchannel(sch);
 207         return ret;
 208 }
 209
 210 static int
 211 check_subchannel(struct device * dev, void * data)
 212 {
 213         struct subchannel *sch;
 214         struct subchannel_id *schid = data;
 215
 216         sch = to_subchannel(dev);
 217         return schid_equal(&sch->schid, schid);
 218 }
 219
 220 struct subchannel *
 221 get_subchannel_by_schid(struct subchannel_id schid)
 222 {
 223         struct device *dev;
 224
 225         dev = bus_find_device(&css_bus_type, NULL,
 226                               &schid, check_subchannel);
 227
 228         return dev ? to_subchannel(dev) : NULL;
 229 }
 230
 231 static int css_get_subchannel_status(struct subchannel *sch)
 232 {
 233         struct schib schib;
 234
 235         if (stsch(sch->schid, &schib) || !schib.pmcw.dnv)
 236                 return CIO_GONE;
 237         if (sch->schib.pmcw.dnv && (schib.pmcw.dev != sch->schib.pmcw.dev))
 238                 return CIO_REVALIDATE;
 239         if (!sch->lpm)
 240                 return CIO_NO_PATH;
 241         return CIO_OPER;
 242 }
 243
 244 static int css_evaluate_known_subchannel(struct subchannel *sch, int slow)
 245 {
 246         int event, ret, disc;
 247         unsigned long flags;
 248         enum { NONE, UNREGISTER, UNREGISTER_PROBE, REPROBE } action;
 249
 250         spin_lock_irqsave(sch->lock, flags);
 251         disc = device_is_disconnected(sch);
 252         if (disc && slow) {
 253                 /* Disconnected devices are evaluated directly only.*/
 254                 spin_unlock_irqrestore(sch->lock, flags);
 255                 return 0;
 256         }
 257         /* No interrupt after machine check - kill pending timers. */
 258         device_kill_pending_timer(sch);
 259         if (!disc && !slow) {
 260                 /* Non-disconnected devices are evaluated on the slow path. */
 261                 spin_unlock_irqrestore(sch->lock, flags);
 262                 return -EAGAIN;
 263         }
 264         event = css_get_subchannel_status(sch);
 265         CIO_MSG_EVENT(4, "Evaluating schid 0.%x.%04x, event %d, %s, %s path.\n",
 266                       sch->schid.ssid, sch->schid.sch_no, event,
 267                       disc ? "disconnected" : "normal",
 268                       slow ? "slow" : "fast");
 269         /* Analyze subchannel status. */
 270         action = NONE;
 271         switch (event) {
 272         case CIO_NO_PATH:
 273                 if (disc) {
 274                         /* Check if paths have become available. */
 275                         action = REPROBE;
 276                         break;
 277                 }
 278                 /* fall through */
 279         case CIO_GONE:
 280                 /* Prevent unwanted effects when opening lock. */
 281                 cio_disable_subchannel(sch);
 282                 device_set_disconnected(sch);
 283                 /* Ask driver what to do with device. */
 284                 action = UNREGISTER;
 285                 if (sch->driver && sch->driver->notify) {
 286                         spin_unlock_irqrestore(sch->lock, flags);
 287                         ret = sch->driver->notify(&sch->dev, event);
 288                         spin_lock_irqsave(sch->lock, flags);
 289                         if (ret)
 290                                 action = NONE;
 291                 }
 292                 break;
 293         case CIO_REVALIDATE:
 294                 /* Device will be removed, so no notify necessary. */
 295                 if (disc)
 296                         /* Reprobe because immediate unregister might block. */
 297                         action = REPROBE;
 298                 else
 299                         action = UNREGISTER_PROBE;
 300                 break;
 301         case CIO_OPER:
 302                 if (disc)
 303                         /* Get device operational again. */
 304                         action = REPROBE;
 305                 break;
 306         }
 307         /* Perform action. */
 308         ret = 0;
 309         switch (action) {
 310         case UNREGISTER:
 311         case UNREGISTER_PROBE:
 312                 /* Unregister device (will use subchannel lock). */
 313                 spin_unlock_irqrestore(sch->lock, flags);
 314                 css_sch_device_unregister(sch);
 315                 spin_lock_irqsave(sch->lock, flags);
 316
 317                 /* Reset intparm to zeroes. */
 318                 sch->schib.pmcw.intparm = 0;
 319                 cio_modify(sch);
 320                 break;
 321         case REPROBE:
 322                 device_trigger_reprobe(sch);
 323                 break;
 324         default:
 325                 break;
 326         }
 327         spin_unlock_irqrestore(sch->lock, flags);
 328         /* Probe if necessary. */
 329         if (action == UNREGISTER_PROBE)
 330                 ret = css_probe_device(sch->schid);
 331
 332         return ret;
 333 }
 334
 335 static int css_evaluate_new_subchannel(struct subchannel_id schid, int slow)
 336 {
 337         struct schib schib;
 338
 339         if (!slow) {
 340                 /* Will be done on the slow path. */
 341                 return -EAGAIN;
 342         }
 343         if (stsch_err(schid, &schib) || !schib.pmcw.dnv) {
 344                 /* Unusable - ignore. */
 345                 return 0;
 346         }
 347         CIO_MSG_EVENT(4, "Evaluating schid 0.%x.%04x, event %d, unknown, "
 348                          "slow path.\n", schid.ssid, schid.sch_no, CIO_OPER);
 349
 350         return css_probe_device(schid);
 351 }
 352
 353 static void css_evaluate_subchannel(struct subchannel_id schid, int slow)
 354 {
 355         struct subchannel *sch;
 356         int ret;
 357
 358         sch = get_subchannel_by_schid(schid);
 359         if (sch) {
 360                 ret = css_evaluate_known_subchannel(sch, slow);
 361                 put_device(&sch->dev);
 362         } else
 363                 ret = css_evaluate_new_subchannel(schid, slow);
 364         if (ret == -EAGAIN)
 365                 css_schedule_eval(schid);
 366 }
 367
 368 static struct idset *slow_subchannel_set;
 369 static spinlock_t slow_subchannel_lock;
 370
 371 static int __init slow_subchannel_init(void)
 372 {
 373         spin_lock_init(&slow_subchannel_lock);
 374         slow_subchannel_set = idset_sch_new();
 375         if (!slow_subchannel_set) {
 376                 CIO_MSG_EVENT(0, "could not allocate slow subchannel set\n");
 377                 return -ENOMEM;
 378         }
 379         return 0;
 380 }
 381
 382 static void css_slow_path_func(struct work_struct *unused)
 383 {
 384         struct subchannel_id schid;
 385
 386         CIO_TRACE_EVENT(4, "slowpath");
 387         spin_lock_irq(&slow_subchannel_lock);
 388         init_subchannel_id(&schid);
 389         while (idset_sch_get_first(slow_subchannel_set, &schid)) {
 390                 idset_sch_del(slow_subchannel_set, schid);
 391                 spin_unlock_irq(&slow_subchannel_lock);
 392                 css_evaluate_subchannel(schid, 1);
 393                 spin_lock_irq(&slow_subchannel_lock);
 394         }
 395         spin_unlock_irq(&slow_subchannel_lock);
 396 }
 397
 398 static DECLARE_WORK(slow_path_work, css_slow_path_func);
 399 struct workqueue_struct *slow_path_wq;
 400
 401 void css_schedule_eval(struct subchannel_id schid)
 402 {
 403         unsigned long flags;
 404
 405         spin_lock_irqsave(&slow_subchannel_lock, flags);
 406         idset_sch_add(slow_subchannel_set, schid);
 407         queue_work(slow_path_wq, &slow_path_work);
 408         spin_unlock_irqrestore(&slow_subchannel_lock, flags);
 409 }
 410
 411 void css_schedule_eval_all(void)
 412 {
 413         unsigned long flags;
 414
 415         spin_lock_irqsave(&slow_subchannel_lock, flags);
 416         idset_fill(slow_subchannel_set);
 417         queue_work(slow_path_wq, &slow_path_work);
 418         spin_unlock_irqrestore(&slow_subchannel_lock, flags);
 419 }
 420
 421 /* Reprobe subchannel if unregistered. */
 422 static int reprobe_subchannel(struct subchannel_id schid, void *data)
 423 {
 424         struct subchannel *sch;
 425         int ret;
 426
 427         CIO_MSG_EVENT(6, "cio: reprobe 0.%x.%04x\n",
 428                       schid.ssid, schid.sch_no);
 429         if (need_reprobe)
 430                 return -EAGAIN;
 431
 432         sch = get_subchannel_by_schid(schid);
 433         if (sch) {
 434                 /* Already known. */
 435                 put_device(&sch->dev);
 436                 return 0;
 437         }
 438
 439         ret = css_probe_device(schid);
 440         switch (ret) {
 441         case 0:
 442                 break;
 443         case -ENXIO:
 444         case -ENOMEM:
 445                 /* These should abort looping */
 446                 break;
 447         default:
 448                 ret = 0;
 449         }
 450
 451         return ret;
 452 }
 453
 454 /* Work function used to reprobe all unregistered subchannels. */
 455 static void reprobe_all(struct work_struct *unused)
 456 {
 457         int ret;
 458
 459         CIO_MSG_EVENT(2, "reprobe start\n");
 460
 461         need_reprobe = 0;
 462         /* Make sure initial subchannel scan is done. */
 463         wait_event(ccw_device_init_wq,
 464                    atomic_read(&ccw_device_init_count) == 0);
 465         ret = for_each_subchannel(reprobe_subchannel, NULL);
 466
 467         CIO_MSG_EVENT(2, "reprobe done (rc=%d, need_reprobe=%d)\n", ret,
 468                       need_reprobe);
 469 }
 470
 471 static DECLARE_WORK(css_reprobe_work, reprobe_all);
 472
 473 /* Schedule reprobing of all unregistered subchannels. */
 474 void css_schedule_reprobe(void)
 475 {
 476         need_reprobe = 1;
 477         queue_work(ccw_device_work, &css_reprobe_work);
 478 }
 479
 480 EXPORT_SYMBOL_GPL(css_schedule_reprobe);
 481
 482 /*
 483  * Called from the machine check handler for subchannel report words.
 484  */
 485 void css_process_crw(int rsid1, int rsid2)
 486 {
 487         struct subchannel_id mchk_schid;
 488
 489         CIO_CRW_EVENT(2, "source is subchannel %04X, subsystem id %x\n",
 490                       rsid1, rsid2);
 491         init_subchannel_id(&mchk_schid);
 492         mchk_schid.sch_no = rsid1;
 493         if (rsid2 != 0)
 494                 mchk_schid.ssid = (rsid2 >> 8) & 3;
 495
 496         /*
 497          * Since we are always presented with IPI in the CRW, we have to
 498          * use stsch() to find out if the subchannel in question has come
 499          * or gone.
 500          */
 501         css_evaluate_subchannel(mchk_schid, 0);
 502 }
 503
 504 static int __init
 505 __init_channel_subsystem(struct subchannel_id schid, void *data)
 506 {
 507         struct subchannel *sch;
 508         int ret;
 509
 510         if (cio_is_console(schid))
 511                 sch = cio_get_console_subchannel();
 512         else {
 513                 sch = css_alloc_subchannel(schid);
 514                 if (IS_ERR(sch))
 515                         ret = PTR_ERR(sch);
 516                 else
 517                         ret = 0;
 518                 switch (ret) {
 519                 case 0:
 520                         break;
 521                 case -ENOMEM:
 522                         panic("Out of memory in init_channel_subsystem\n");
 523                 /* -ENXIO: no more subchannels. */
 524                 case -ENXIO:
 525                         return ret;
 526                 /* -EIO: this subchannel set not supported. */
 527                 case -EIO:
 528                         return ret;
 529                 default:
 530                         return 0;
 531                 }
 532         }
 533         /*
 534          * We register ALL valid subchannels in ioinfo, even those
 535          * that have been present before init_channel_subsystem.
 536          * These subchannels can't have been registered yet (kmalloc
 537          * not working) so we do it now. This is true e.g. for the
 538          * console subchannel.
 539          */
 540         css_register_subchannel(sch);
 541         return 0;
 542 }
 543
 544 static void __init
 545 css_generate_pgid(struct channel_subsystem *css, u32 tod_high)
 546 {
 547         if (css_characteristics_avail && css_general_characteristics.mcss) {
 548                 css->global_pgid.pgid_high.ext_cssid.version = 0x80;
 549                 css->global_pgid.pgid_high.ext_cssid.cssid = css->cssid;
 550         } else {
 551 #ifdef CONFIG_SMP
 552                 css->global_pgid.pgid_high.cpu_addr = hard_smp_processor_id();
 553 #else
 554                 css->global_pgid.pgid_high.cpu_addr = 0;
 555 #endif
 556         }
 557         css->global_pgid.cpu_id = ((cpuid_t *) __LC_CPUID)->ident;
 558         css->global_pgid.cpu_model = ((cpuid_t *) __LC_CPUID)->machine;
 559         css->global_pgid.tod_high = tod_high;
 560
 561 }
 562
 563 static void
 564 channel_subsystem_release(struct device *dev)
 565 {
 566         struct channel_subsystem *css;
 567
 568         css = to_css(dev);
 569         mutex_destroy(&css->mutex);
 570         kfree(css);
 571 }
 572
 573 static ssize_t
 574 css_cm_enable_show(struct device *dev, struct device_attribute *attr,
 575                    char *buf)
 576 {
 577         struct channel_subsystem *css = to_css(dev);
 578
 579         if (!css)
 580                 return 0;
 581         return sprintf(buf, "%x\n", css->cm_enabled);
 582 }
 583
 584 static ssize_t
 585 css_cm_enable_store(struct device *dev, struct device_attribute *attr,
 586                     const char *buf, size_t count)
 587 {
 588         struct channel_subsystem *css = to_css(dev);
 589         int ret;
 590
 591         switch (buf[0]) {
 592         case '0':
 593                 ret = css->cm_enabled ? chsc_secm(css, 0) : 0;
 594                 break;
 595         case '1':
 596                 ret = css->cm_enabled ? 0 : chsc_secm(css, 1);
 597                 break;
 598         default:
 599                 ret = -EINVAL;
 600         }
 601         return ret < 0 ? ret : count;
 602 }
 603
 604 static DEVICE_ATTR(cm_enable, 0644, css_cm_enable_show, css_cm_enable_store);
 605
 606 static int __init setup_css(int nr)
 607 {
 608         u32 tod_high;
 609         int ret;
 610         struct channel_subsystem *css;
 611
 612         css = channel_subsystems[nr];
 613         memset(css, 0, sizeof(struct channel_subsystem));
 614         css->pseudo_subchannel =
 615                 kzalloc(sizeof(*css->pseudo_subchannel), GFP_KERNEL);
 616         if (!css->pseudo_subchannel)
 617                 return -ENOMEM;
 618         css->pseudo_subchannel->dev.parent = &css->device;
 619         css->pseudo_subchannel->dev.release = css_subchannel_release;
 620         sprintf(css->pseudo_subchannel->dev.bus_id, "defunct");
 621         ret = cio_create_sch_lock(css->pseudo_subchannel);
 622         if (ret) {
 623                 kfree(css->pseudo_subchannel);
 624                 return ret;
 625         }
 626         mutex_init(&css->mutex);
 627         css->valid = 1;
 628         css->cssid = nr;
 629         sprintf(css->device.bus_id, "css%x", nr);
 630         css->device.release = channel_subsystem_release;
 631         tod_high = (u32) (get_clock() >> 32);
 632         css_generate_pgid(css, tod_high);
 633         return 0;
 634 }
 635
 636 static int css_reboot_event(struct notifier_block *this,
 637                             unsigned long event,
 638                             void *ptr)
 639 {
 640         int ret, i;
 641
 642         ret = NOTIFY_DONE;
 643         for (i = 0; i <= __MAX_CSSID; i++) {
 644                 struct channel_subsystem *css;
 645
 646                 css = channel_subsystems[i];
 647                 if (css->cm_enabled)
 648                         if (chsc_secm(css, 0))
 649                                 ret = NOTIFY_BAD;
 650         }
 651
 652         return ret;
 653 }
 654
 655 static struct notifier_block css_reboot_notifier = {
 656         .notifier_call = css_reboot_event,
 657 };
 658
 659 /*
 660  * Now that the driver core is running, we can setup our channel subsystem.
 661  * The struct subchannel's are created during probing (except for the
 662  * static console subchannel).
 663  */
 664 static int __init
 665 init_channel_subsystem (void)
 666 {
 667         int ret, i;
 668
 669         ret = chsc_determine_css_characteristics();
 670         if (ret == -ENOMEM)
 671                 goto out; /* No need to continue. */
 672         if (ret == 0)
 673                 css_characteristics_avail = 1;
 674
 675         ret = chsc_alloc_sei_area();
 676         if (ret)
 677                 goto out;
 678
 679         ret = slow_subchannel_init();
 680         if (ret)
 681                 goto out;
 682
 683         if ((ret = bus_register(&css_bus_type)))
 684                 goto out;
 685
 686         /* Try to enable MSS. */
 687         ret = chsc_enable_facility(CHSC_SDA_OC_MSS);
 688         switch (ret) {
 689         case 0: /* Success. */
 690                 max_ssid = __MAX_SSID;
 691                 break;
 692         case -ENOMEM:
 693                 goto out_bus;
 694         default:
 695                 max_ssid = 0;
 696         }
 697         /* Setup css structure. */
 698         for (i = 0; i <= __MAX_CSSID; i++) {
 699                 struct channel_subsystem *css;
 700
 701                 css = kmalloc(sizeof(struct channel_subsystem), GFP_KERNEL);
 702                 if (!css) {
 703                         ret = -ENOMEM;
 704                         goto out_unregister;
 705                 }
 706                 channel_subsystems[i] = css;
 707                 ret = setup_css(i);
 708                 if (ret)
 709                         goto out_free;
 710                 ret = device_register(&css->device);
 711                 if (ret)
 712                         goto out_free_all;
 713                 if (css_characteristics_avail &&
 714                     css_chsc_characteristics.secm) {
 715                         ret = device_create_file(&css->device,
 716                                                  &dev_attr_cm_enable);
 717                         if (ret)
 718                                 goto out_device;
 719                 }
 720                 ret = device_register(&css->pseudo_subchannel->dev);
 721                 if (ret)
 722                         goto out_file;
 723         }
 724         ret = register_reboot_notifier(&css_reboot_notifier);
 725         if (ret)
 726                 goto out_pseudo;
 727         css_init_done = 1;
 728
 729         ctl_set_bit(6, 28);
 730
 731         for_each_subchannel(__init_channel_subsystem, NULL);
 732         return 0;
 733 out_pseudo:
 734         device_unregister(&channel_subsystems[i]->pseudo_subchannel->dev);
 735 out_file:
 736         device_remove_file(&channel_subsystems[i]->device,
 737                            &dev_attr_cm_enable);
 738 out_device:
 739         device_unregister(&channel_subsystems[i]->device);
 740 out_free_all:
 741         kfree(channel_subsystems[i]->pseudo_subchannel->lock);
 742         kfree(channel_subsystems[i]->pseudo_subchannel);
 743 out_free:
 744         kfree(channel_subsystems[i]);
 745 out_unregister:
 746         while (i > 0) {
 747                 struct channel_subsystem *css;
 748
 749                 i--;
 750                 css = channel_subsystems[i];
 751                 device_unregister(&css->pseudo_subchannel->dev);
 752                 if (css_characteristics_avail && css_chsc_characteristics.secm)
 753                         device_remove_file(&css->device,
 754                                            &dev_attr_cm_enable);
 755                 device_unregister(&css->device);
 756         }
 757 out_bus:
 758         bus_unregister(&css_bus_type);
 759 out:
 760         chsc_free_sei_area();
 761         kfree(slow_subchannel_set);
 762         printk(KERN_WARNING"cio: failed to initialize css driver (%d)!\n",
 763                ret);
 764         return ret;
 765 }
 766
 767 int sch_is_pseudo_sch(struct subchannel *sch)
 768 {
 769         return sch == to_css(sch->dev.parent)->pseudo_subchannel;
 770 }
 771
 772 /*
 773  * find a driver for a subchannel. They identify by the subchannel
 774  * type with the exception that the console subchannel driver has its own
 775  * subchannel type although the device is an i/o subchannel
 776  */
 777 static int
 778 css_bus_match (struct device *dev, struct device_driver *drv)
 779 {
 780         struct subchannel *sch = container_of (dev, struct subchannel, dev);
 781         struct css_driver *driver = container_of (drv, struct css_driver, drv);
 782
 783         if (sch->st == driver->subchannel_type)
 784                 return 1;
 785
 786         return 0;
 787 }
 788
 789 static int
 790 css_probe (struct device *dev)
 791 {
 792         struct subchannel *sch;
 793
 794         sch = to_subchannel(dev);
 795         sch->driver = container_of (dev->driver, struct css_driver, drv);
 796         return (sch->driver->probe ? sch->driver->probe(sch) : 0);
 797 }
 798
 799 static int
 800 css_remove (struct device *dev)
 801 {
 802         struct subchannel *sch;
 803
 804         sch = to_subchannel(dev);
 805         return (sch->driver->remove ? sch->driver->remove(sch) : 0);
 806 }
 807
 808 static void
 809 css_shutdown (struct device *dev)
 810 {
 811         struct subchannel *sch;
 812
 813         sch = to_subchannel(dev);
 814         if (sch->driver->shutdown)
 815                 sch->driver->shutdown(sch);
 816 }
 817
 818 struct bus_type css_bus_type = {
 819         .name     = "css",
 820         .match    = css_bus_match,
 821         .probe    = css_probe,
 822         .remove   = css_remove,
 823         .shutdown = css_shutdown,
 824 };
 825
 826 subsys_initcall(init_channel_subsystem);
 827
 828 MODULE_LICENSE("GPL");
 829 EXPORT_SYMBOL(css_bus_type);
 830 EXPORT_SYMBOL_GPL(css_characteristics_avail);