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         /*
 186          * We don't want to generate uevents for I/O subchannels that don't
 187          * have a working ccw device behind them since they will be
 188          * unregistered before they can be used anyway, so we delay the add
 189          * uevent until after device recognition was successful.
 190          */
 191         if (!cio_is_console(sch->schid))
 192                 /* Console is special, no need to suppress. */
 193                 sch->dev.uevent_suppress = 1;
 194         css_update_ssd_info(sch);
 195         /* make it known to the system */
 196         ret = css_sch_device_register(sch);
 197         if (ret) {
 198                 CIO_MSG_EVENT(0, "Could not register sch 0.%x.%04x: %d\n",
 199                               sch->schid.ssid, sch->schid.sch_no, ret);
 200                 return ret;
 201         }
 202         return ret;
 203 }
 204
 205 static int css_probe_device(struct subchannel_id schid)
 206 {
 207         int ret;
 208         struct subchannel *sch;
 209
 210         sch = css_alloc_subchannel(schid);
 211         if (IS_ERR(sch))
 212                 return PTR_ERR(sch);
 213         ret = css_register_subchannel(sch);
 214         if (ret)
 215                 css_free_subchannel(sch);
 216         return ret;
 217 }
 218
 219 static int
 220 check_subchannel(struct device * dev, void * data)
 221 {
 222         struct subchannel *sch;
 223         struct subchannel_id *schid = data;
 224
 225         sch = to_subchannel(dev);
 226         return schid_equal(&sch->schid, schid);
 227 }
 228
 229 struct subchannel *
 230 get_subchannel_by_schid(struct subchannel_id schid)
 231 {
 232         struct device *dev;
 233
 234         dev = bus_find_device(&css_bus_type, NULL,
 235                               &schid, check_subchannel);
 236
 237         return dev ? to_subchannel(dev) : NULL;
 238 }
 239
 240 static int css_get_subchannel_status(struct subchannel *sch)
 241 {
 242         struct schib schib;
 243
 244         if (stsch(sch->schid, &schib) || !schib.pmcw.dnv)
 245                 return CIO_GONE;
 246         if (sch->schib.pmcw.dnv && (schib.pmcw.dev != sch->schib.pmcw.dev))
 247                 return CIO_REVALIDATE;
 248         if (!sch->lpm)
 249                 return CIO_NO_PATH;
 250         return CIO_OPER;
 251 }
 252
 253 static int css_evaluate_known_subchannel(struct subchannel *sch, int slow)
 254 {
 255         int event, ret, disc;
 256         unsigned long flags;
 257         enum { NONE, UNREGISTER, UNREGISTER_PROBE, REPROBE } action;
 258
 259         spin_lock_irqsave(sch->lock, flags);
 260         disc = device_is_disconnected(sch);
 261         if (disc && slow) {
 262                 /* Disconnected devices are evaluated directly only.*/
 263                 spin_unlock_irqrestore(sch->lock, flags);
 264                 return 0;
 265         }
 266         /* No interrupt after machine check - kill pending timers. */
 267         device_kill_pending_timer(sch);
 268         if (!disc && !slow) {
 269                 /* Non-disconnected devices are evaluated on the slow path. */
 270                 spin_unlock_irqrestore(sch->lock, flags);
 271                 return -EAGAIN;
 272         }
 273         event = css_get_subchannel_status(sch);
 274         CIO_MSG_EVENT(4, "Evaluating schid 0.%x.%04x, event %d, %s, %s path.\n",
 275                       sch->schid.ssid, sch->schid.sch_no, event,
 276                       disc ? "disconnected" : "normal",
 277                       slow ? "slow" : "fast");
 278         /* Analyze subchannel status. */
 279         action = NONE;
 280         switch (event) {
 281         case CIO_NO_PATH:
 282                 if (disc) {
 283                         /* Check if paths have become available. */
 284                         action = REPROBE;
 285                         break;
 286                 }
 287                 /* fall through */
 288         case CIO_GONE:
 289                 /* Prevent unwanted effects when opening lock. */
 290                 cio_disable_subchannel(sch);
 291                 device_set_disconnected(sch);
 292                 /* Ask driver what to do with device. */
 293                 action = UNREGISTER;
 294                 if (sch->driver && sch->driver->notify) {
 295                         spin_unlock_irqrestore(sch->lock, flags);
 296                         ret = sch->driver->notify(sch, event);
 297                         spin_lock_irqsave(sch->lock, flags);
 298                         if (ret)
 299                                 action = NONE;
 300                 }
 301                 break;
 302         case CIO_REVALIDATE:
 303                 /* Device will be removed, so no notify necessary. */
 304                 if (disc)
 305                         /* Reprobe because immediate unregister might block. */
 306                         action = REPROBE;
 307                 else
 308                         action = UNREGISTER_PROBE;
 309                 break;
 310         case CIO_OPER:
 311                 if (disc)
 312                         /* Get device operational again. */
 313                         action = REPROBE;
 314                 break;
 315         }
 316         /* Perform action. */
 317         ret = 0;
 318         switch (action) {
 319         case UNREGISTER:
 320         case UNREGISTER_PROBE:
 321                 /* Unregister device (will use subchannel lock). */
 322                 spin_unlock_irqrestore(sch->lock, flags);
 323                 css_sch_device_unregister(sch);
 324                 spin_lock_irqsave(sch->lock, flags);
 325
 326                 /* Reset intparm to zeroes. */
 327                 sch->schib.pmcw.intparm = 0;
 328                 cio_modify(sch);
 329                 break;
 330         case REPROBE:
 331                 device_trigger_reprobe(sch);
 332                 break;
 333         default:
 334                 break;
 335         }
 336         spin_unlock_irqrestore(sch->lock, flags);
 337         /* Probe if necessary. */
 338         if (action == UNREGISTER_PROBE)
 339                 ret = css_probe_device(sch->schid);
 340
 341         return ret;
 342 }
 343
 344 static int css_evaluate_new_subchannel(struct subchannel_id schid, int slow)
 345 {
 346         struct schib schib;
 347
 348         if (!slow) {
 349                 /* Will be done on the slow path. */
 350                 return -EAGAIN;
 351         }
 352         if (stsch_err(schid, &schib) || !schib.pmcw.dnv) {
 353                 /* Unusable - ignore. */
 354                 return 0;
 355         }
 356         CIO_MSG_EVENT(4, "Evaluating schid 0.%x.%04x, event %d, unknown, "
 357                          "slow path.\n", schid.ssid, schid.sch_no, CIO_OPER);
 358
 359         return css_probe_device(schid);
 360 }
 361
 362 static void css_evaluate_subchannel(struct subchannel_id schid, int slow)
 363 {
 364         struct subchannel *sch;
 365         int ret;
 366
 367         sch = get_subchannel_by_schid(schid);
 368         if (sch) {
 369                 ret = css_evaluate_known_subchannel(sch, slow);
 370                 put_device(&sch->dev);
 371         } else
 372                 ret = css_evaluate_new_subchannel(schid, slow);
 373         if (ret == -EAGAIN)
 374                 css_schedule_eval(schid);
 375 }
 376
 377 static struct idset *slow_subchannel_set;
 378 static spinlock_t slow_subchannel_lock;
 379
 380 static int __init slow_subchannel_init(void)
 381 {
 382         spin_lock_init(&slow_subchannel_lock);
 383         slow_subchannel_set = idset_sch_new();
 384         if (!slow_subchannel_set) {
 385                 CIO_MSG_EVENT(0, "could not allocate slow subchannel set\n");
 386                 return -ENOMEM;
 387         }
 388         return 0;
 389 }
 390
 391 static void css_slow_path_func(struct work_struct *unused)
 392 {
 393         struct subchannel_id schid;
 394
 395         CIO_TRACE_EVENT(4, "slowpath");
 396         spin_lock_irq(&slow_subchannel_lock);
 397         init_subchannel_id(&schid);
 398         while (idset_sch_get_first(slow_subchannel_set, &schid)) {
 399                 idset_sch_del(slow_subchannel_set, schid);
 400                 spin_unlock_irq(&slow_subchannel_lock);
 401                 css_evaluate_subchannel(schid, 1);
 402                 spin_lock_irq(&slow_subchannel_lock);
 403         }
 404         spin_unlock_irq(&slow_subchannel_lock);
 405 }
 406
 407 static DECLARE_WORK(slow_path_work, css_slow_path_func);
 408 struct workqueue_struct *slow_path_wq;
 409
 410 void css_schedule_eval(struct subchannel_id schid)
 411 {
 412         unsigned long flags;
 413
 414         spin_lock_irqsave(&slow_subchannel_lock, flags);
 415         idset_sch_add(slow_subchannel_set, schid);
 416         queue_work(slow_path_wq, &slow_path_work);
 417         spin_unlock_irqrestore(&slow_subchannel_lock, flags);
 418 }
 419
 420 void css_schedule_eval_all(void)
 421 {
 422         unsigned long flags;
 423
 424         spin_lock_irqsave(&slow_subchannel_lock, flags);
 425         idset_fill(slow_subchannel_set);
 426         queue_work(slow_path_wq, &slow_path_work);
 427         spin_unlock_irqrestore(&slow_subchannel_lock, flags);
 428 }
 429
 430 /* Reprobe subchannel if unregistered. */
 431 static int reprobe_subchannel(struct subchannel_id schid, void *data)
 432 {
 433         struct subchannel *sch;
 434         int ret;
 435
 436         CIO_MSG_EVENT(6, "cio: reprobe 0.%x.%04x\n",
 437                       schid.ssid, schid.sch_no);
 438         if (need_reprobe)
 439                 return -EAGAIN;
 440
 441         sch = get_subchannel_by_schid(schid);
 442         if (sch) {
 443                 /* Already known. */
 444                 put_device(&sch->dev);
 445                 return 0;
 446         }
 447
 448         ret = css_probe_device(schid);
 449         switch (ret) {
 450         case 0:
 451                 break;
 452         case -ENXIO:
 453         case -ENOMEM:
 454         case -EIO:
 455                 /* These should abort looping */
 456                 break;
 457         default:
 458                 ret = 0;
 459         }
 460
 461         return ret;
 462 }
 463
 464 /* Work function used to reprobe all unregistered subchannels. */
 465 static void reprobe_all(struct work_struct *unused)
 466 {
 467         int ret;
 468
 469         CIO_MSG_EVENT(2, "reprobe start\n");
 470
 471         need_reprobe = 0;
 472         /* Make sure initial subchannel scan is done. */
 473         wait_event(ccw_device_init_wq,
 474                    atomic_read(&ccw_device_init_count) == 0);
 475         ret = for_each_subchannel(reprobe_subchannel, NULL);
 476
 477         CIO_MSG_EVENT(2, "reprobe done (rc=%d, need_reprobe=%d)\n", ret,
 478                       need_reprobe);
 479 }
 480
 481 static DECLARE_WORK(css_reprobe_work, reprobe_all);
 482
 483 /* Schedule reprobing of all unregistered subchannels. */
 484 void css_schedule_reprobe(void)
 485 {
 486         need_reprobe = 1;
 487         queue_work(slow_path_wq, &css_reprobe_work);
 488 }
 489
 490 EXPORT_SYMBOL_GPL(css_schedule_reprobe);
 491
 492 /*
 493  * Called from the machine check handler for subchannel report words.
 494  */
 495 void css_process_crw(int rsid1, int rsid2)
 496 {
 497         struct subchannel_id mchk_schid;
 498
 499         CIO_CRW_EVENT(2, "source is subchannel %04X, subsystem id %x\n",
 500                       rsid1, rsid2);
 501         init_subchannel_id(&mchk_schid);
 502         mchk_schid.sch_no = rsid1;
 503         if (rsid2 != 0)
 504                 mchk_schid.ssid = (rsid2 >> 8) & 3;
 505
 506         /*
 507          * Since we are always presented with IPI in the CRW, we have to
 508          * use stsch() to find out if the subchannel in question has come
 509          * or gone.
 510          */
 511         css_evaluate_subchannel(mchk_schid, 0);
 512 }
 513
 514 static int __init
 515 __init_channel_subsystem(struct subchannel_id schid, void *data)
 516 {
 517         struct subchannel *sch;
 518         int ret;
 519
 520         if (cio_is_console(schid))
 521                 sch = cio_get_console_subchannel();
 522         else {
 523                 sch = css_alloc_subchannel(schid);
 524                 if (IS_ERR(sch))
 525                         ret = PTR_ERR(sch);
 526                 else
 527                         ret = 0;
 528                 switch (ret) {
 529                 case 0:
 530                         break;
 531                 case -ENOMEM:
 532                         panic("Out of memory in init_channel_subsystem\n");
 533                 /* -ENXIO: no more subchannels. */
 534                 case -ENXIO:
 535                         return ret;
 536                 /* -EIO: this subchannel set not supported. */
 537                 case -EIO:
 538                         return ret;
 539                 default:
 540                         return 0;
 541                 }
 542         }
 543         /*
 544          * We register ALL valid subchannels in ioinfo, even those
 545          * that have been present before init_channel_subsystem.
 546          * These subchannels can't have been registered yet (kmalloc
 547          * not working) so we do it now. This is true e.g. for the
 548          * console subchannel.
 549          */
 550         css_register_subchannel(sch);
 551         return 0;
 552 }
 553
 554 static void __init
 555 css_generate_pgid(struct channel_subsystem *css, u32 tod_high)
 556 {
 557         if (css_characteristics_avail && css_general_characteristics.mcss) {
 558                 css->global_pgid.pgid_high.ext_cssid.version = 0x80;
 559                 css->global_pgid.pgid_high.ext_cssid.cssid = css->cssid;
 560         } else {
 561 #ifdef CONFIG_SMP
 562                 css->global_pgid.pgid_high.cpu_addr = hard_smp_processor_id();
 563 #else
 564                 css->global_pgid.pgid_high.cpu_addr = 0;
 565 #endif
 566         }
 567         css->global_pgid.cpu_id = ((cpuid_t *) __LC_CPUID)->ident;
 568         css->global_pgid.cpu_model = ((cpuid_t *) __LC_CPUID)->machine;
 569         css->global_pgid.tod_high = tod_high;
 570
 571 }
 572
 573 static void
 574 channel_subsystem_release(struct device *dev)
 575 {
 576         struct channel_subsystem *css;
 577
 578         css = to_css(dev);
 579         mutex_destroy(&css->mutex);
 580         kfree(css);
 581 }
 582
 583 static ssize_t
 584 css_cm_enable_show(struct device *dev, struct device_attribute *attr,
 585                    char *buf)
 586 {
 587         struct channel_subsystem *css = to_css(dev);
 588
 589         if (!css)
 590                 return 0;
 591         return sprintf(buf, "%x\n", css->cm_enabled);
 592 }
 593
 594 static ssize_t
 595 css_cm_enable_store(struct device *dev, struct device_attribute *attr,
 596                     const char *buf, size_t count)
 597 {
 598         struct channel_subsystem *css = to_css(dev);
 599         int ret;
 600
 601         switch (buf[0]) {
 602         case '0':
 603                 ret = css->cm_enabled ? chsc_secm(css, 0) : 0;
 604                 break;
 605         case '1':
 606                 ret = css->cm_enabled ? 0 : chsc_secm(css, 1);
 607                 break;
 608         default:
 609                 ret = -EINVAL;
 610         }
 611         return ret < 0 ? ret : count;
 612 }
 613
 614 static DEVICE_ATTR(cm_enable, 0644, css_cm_enable_show, css_cm_enable_store);
 615
 616 static int __init setup_css(int nr)
 617 {
 618         u32 tod_high;
 619         int ret;
 620         struct channel_subsystem *css;
 621
 622         css = channel_subsystems[nr];
 623         memset(css, 0, sizeof(struct channel_subsystem));
 624         css->pseudo_subchannel =
 625                 kzalloc(sizeof(*css->pseudo_subchannel), GFP_KERNEL);
 626         if (!css->pseudo_subchannel)
 627                 return -ENOMEM;
 628         css->pseudo_subchannel->dev.parent = &css->device;
 629         css->pseudo_subchannel->dev.release = css_subchannel_release;
 630         sprintf(css->pseudo_subchannel->dev.bus_id, "defunct");
 631         ret = cio_create_sch_lock(css->pseudo_subchannel);
 632         if (ret) {
 633                 kfree(css->pseudo_subchannel);
 634                 return ret;
 635         }
 636         mutex_init(&css->mutex);
 637         css->valid = 1;
 638         css->cssid = nr;
 639         sprintf(css->device.bus_id, "css%x", nr);
 640         css->device.release = channel_subsystem_release;
 641         tod_high = (u32) (get_clock() >> 32);
 642         css_generate_pgid(css, tod_high);
 643         return 0;
 644 }
 645
 646 static int css_reboot_event(struct notifier_block *this,
 647                             unsigned long event,
 648                             void *ptr)
 649 {
 650         int ret, i;
 651
 652         ret = NOTIFY_DONE;
 653         for (i = 0; i <= __MAX_CSSID; i++) {
 654                 struct channel_subsystem *css;
 655
 656                 css = channel_subsystems[i];
 657                 if (css->cm_enabled)
 658                         if (chsc_secm(css, 0))
 659                                 ret = NOTIFY_BAD;
 660         }
 661
 662         return ret;
 663 }
 664
 665 static struct notifier_block css_reboot_notifier = {
 666         .notifier_call = css_reboot_event,
 667 };
 668
 669 /*
 670  * Now that the driver core is running, we can setup our channel subsystem.
 671  * The struct subchannel's are created during probing (except for the
 672  * static console subchannel).
 673  */
 674 static int __init
 675 init_channel_subsystem (void)
 676 {
 677         int ret, i;
 678
 679         ret = chsc_determine_css_characteristics();
 680         if (ret == -ENOMEM)
 681                 goto out; /* No need to continue. */
 682         if (ret == 0)
 683                 css_characteristics_avail = 1;
 684
 685         ret = chsc_alloc_sei_area();
 686         if (ret)
 687                 goto out;
 688
 689         ret = slow_subchannel_init();
 690         if (ret)
 691                 goto out;
 692
 693         if ((ret = bus_register(&css_bus_type)))
 694                 goto out;
 695
 696         /* Try to enable MSS. */
 697         ret = chsc_enable_facility(CHSC_SDA_OC_MSS);
 698         switch (ret) {
 699         case 0: /* Success. */
 700                 max_ssid = __MAX_SSID;
 701                 break;
 702         case -ENOMEM:
 703                 goto out_bus;
 704         default:
 705                 max_ssid = 0;
 706         }
 707         /* Setup css structure. */
 708         for (i = 0; i <= __MAX_CSSID; i++) {
 709                 struct channel_subsystem *css;
 710
 711                 css = kmalloc(sizeof(struct channel_subsystem), GFP_KERNEL);
 712                 if (!css) {
 713                         ret = -ENOMEM;
 714                         goto out_unregister;
 715                 }
 716                 channel_subsystems[i] = css;
 717                 ret = setup_css(i);
 718                 if (ret)
 719                         goto out_free;
 720                 ret = device_register(&css->device);
 721                 if (ret)
 722                         goto out_free_all;
 723                 if (css_characteristics_avail &&
 724                     css_chsc_characteristics.secm) {
 725                         ret = device_create_file(&css->device,
 726                                                  &dev_attr_cm_enable);
 727                         if (ret)
 728                                 goto out_device;
 729                 }
 730                 ret = device_register(&css->pseudo_subchannel->dev);
 731                 if (ret)
 732                         goto out_file;
 733         }
 734         ret = register_reboot_notifier(&css_reboot_notifier);
 735         if (ret)
 736                 goto out_pseudo;
 737         css_init_done = 1;
 738
 739         ctl_set_bit(6, 28);
 740
 741         for_each_subchannel(__init_channel_subsystem, NULL);
 742         return 0;
 743 out_pseudo:
 744         device_unregister(&channel_subsystems[i]->pseudo_subchannel->dev);
 745 out_file:
 746         device_remove_file(&channel_subsystems[i]->device,
 747                            &dev_attr_cm_enable);
 748 out_device:
 749         device_unregister(&channel_subsystems[i]->device);
 750 out_free_all:
 751         kfree(channel_subsystems[i]->pseudo_subchannel->lock);
 752         kfree(channel_subsystems[i]->pseudo_subchannel);
 753 out_free:
 754         kfree(channel_subsystems[i]);
 755 out_unregister:
 756         while (i > 0) {
 757                 struct channel_subsystem *css;
 758
 759                 i--;
 760                 css = channel_subsystems[i];
 761                 device_unregister(&css->pseudo_subchannel->dev);
 762                 if (css_characteristics_avail && css_chsc_characteristics.secm)
 763                         device_remove_file(&css->device,
 764                                            &dev_attr_cm_enable);
 765                 device_unregister(&css->device);
 766         }
 767 out_bus:
 768         bus_unregister(&css_bus_type);
 769 out:
 770         chsc_free_sei_area();
 771         kfree(slow_subchannel_set);
 772         printk(KERN_WARNING"cio: failed to initialize css driver (%d)!\n",
 773                ret);
 774         return ret;
 775 }
 776
 777 int sch_is_pseudo_sch(struct subchannel *sch)
 778 {
 779         return sch == to_css(sch->dev.parent)->pseudo_subchannel;
 780 }
 781
 782 /*
 783  * find a driver for a subchannel. They identify by the subchannel
 784  * type with the exception that the console subchannel driver has its own
 785  * subchannel type although the device is an i/o subchannel
 786  */
 787 static int
 788 css_bus_match (struct device *dev, struct device_driver *drv)
 789 {
 790         struct subchannel *sch = to_subchannel(dev);
 791         struct css_driver *driver = to_cssdriver(drv);
 792
 793         if (sch->st == driver->subchannel_type)
 794                 return 1;
 795
 796         return 0;
 797 }
 798
 799 static int
 800 css_probe (struct device *dev)
 801 {
 802         struct subchannel *sch;
 803
 804         sch = to_subchannel(dev);
 805         sch->driver = to_cssdriver(dev->driver);
 806         return (sch->driver->probe ? sch->driver->probe(sch) : 0);
 807 }
 808
 809 static int
 810 css_remove (struct device *dev)
 811 {
 812         struct subchannel *sch;
 813
 814         sch = to_subchannel(dev);
 815         return (sch->driver->remove ? sch->driver->remove(sch) : 0);
 816 }
 817
 818 static void
 819 css_shutdown (struct device *dev)
 820 {
 821         struct subchannel *sch;
 822
 823         sch = to_subchannel(dev);
 824         if (sch->driver->shutdown)
 825                 sch->driver->shutdown(sch);
 826 }
 827
 828 struct bus_type css_bus_type = {
 829         .name     = "css",
 830         .match    = css_bus_match,
 831         .probe    = css_probe,
 832         .remove   = css_remove,
 833         .shutdown = css_shutdown,
 834 };
 835
 836 subsys_initcall(init_channel_subsystem);
 837
 838 MODULE_LICENSE("GPL");
 839 EXPORT_SYMBOL(css_bus_type);
 840 EXPORT_SYMBOL_GPL(css_characteristics_avail);