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->dev, 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                 /* These should abort looping */
 455                 break;
 456         default:
 457                 ret = 0;
 458         }
 459
 460         return ret;
 461 }
 462
 463 /* Work function used to reprobe all unregistered subchannels. */
 464 static void reprobe_all(struct work_struct *unused)
 465 {
 466         int ret;
 467
 468         CIO_MSG_EVENT(2, "reprobe start\n");
 469
 470         need_reprobe = 0;
 471         /* Make sure initial subchannel scan is done. */
 472         wait_event(ccw_device_init_wq,
 473                    atomic_read(&ccw_device_init_count) == 0);
 474         ret = for_each_subchannel(reprobe_subchannel, NULL);
 475
 476         CIO_MSG_EVENT(2, "reprobe done (rc=%d, need_reprobe=%d)\n", ret,
 477                       need_reprobe);
 478 }
 479
 480 static DECLARE_WORK(css_reprobe_work, reprobe_all);
 481
 482 /* Schedule reprobing of all unregistered subchannels. */
 483 void css_schedule_reprobe(void)
 484 {
 485         need_reprobe = 1;
 486         queue_work(slow_path_wq, &css_reprobe_work);
 487 }
 488
 489 EXPORT_SYMBOL_GPL(css_schedule_reprobe);
 490
 491 /*
 492  * Called from the machine check handler for subchannel report words.
 493  */
 494 void css_process_crw(int rsid1, int rsid2)
 495 {
 496         struct subchannel_id mchk_schid;
 497
 498         CIO_CRW_EVENT(2, "source is subchannel %04X, subsystem id %x\n",
 499                       rsid1, rsid2);
 500         init_subchannel_id(&mchk_schid);
 501         mchk_schid.sch_no = rsid1;
 502         if (rsid2 != 0)
 503                 mchk_schid.ssid = (rsid2 >> 8) & 3;
 504
 505         /*
 506          * Since we are always presented with IPI in the CRW, we have to
 507          * use stsch() to find out if the subchannel in question has come
 508          * or gone.
 509          */
 510         css_evaluate_subchannel(mchk_schid, 0);
 511 }
 512
 513 static int __init
 514 __init_channel_subsystem(struct subchannel_id schid, void *data)
 515 {
 516         struct subchannel *sch;
 517         int ret;
 518
 519         if (cio_is_console(schid))
 520                 sch = cio_get_console_subchannel();
 521         else {
 522                 sch = css_alloc_subchannel(schid);
 523                 if (IS_ERR(sch))
 524                         ret = PTR_ERR(sch);
 525                 else
 526                         ret = 0;
 527                 switch (ret) {
 528                 case 0:
 529                         break;
 530                 case -ENOMEM:
 531                         panic("Out of memory in init_channel_subsystem\n");
 532                 /* -ENXIO: no more subchannels. */
 533                 case -ENXIO:
 534                         return ret;
 535                 /* -EIO: this subchannel set not supported. */
 536                 case -EIO:
 537                         return ret;
 538                 default:
 539                         return 0;
 540                 }
 541         }
 542         /*
 543          * We register ALL valid subchannels in ioinfo, even those
 544          * that have been present before init_channel_subsystem.
 545          * These subchannels can't have been registered yet (kmalloc
 546          * not working) so we do it now. This is true e.g. for the
 547          * console subchannel.
 548          */
 549         css_register_subchannel(sch);
 550         return 0;
 551 }
 552
 553 static void __init
 554 css_generate_pgid(struct channel_subsystem *css, u32 tod_high)
 555 {
 556         if (css_characteristics_avail && css_general_characteristics.mcss) {
 557                 css->global_pgid.pgid_high.ext_cssid.version = 0x80;
 558                 css->global_pgid.pgid_high.ext_cssid.cssid = css->cssid;
 559         } else {
 560 #ifdef CONFIG_SMP
 561                 css->global_pgid.pgid_high.cpu_addr = hard_smp_processor_id();
 562 #else
 563                 css->global_pgid.pgid_high.cpu_addr = 0;
 564 #endif
 565         }
 566         css->global_pgid.cpu_id = ((cpuid_t *) __LC_CPUID)->ident;
 567         css->global_pgid.cpu_model = ((cpuid_t *) __LC_CPUID)->machine;
 568         css->global_pgid.tod_high = tod_high;
 569
 570 }
 571
 572 static void
 573 channel_subsystem_release(struct device *dev)
 574 {
 575         struct channel_subsystem *css;
 576
 577         css = to_css(dev);
 578         mutex_destroy(&css->mutex);
 579         kfree(css);
 580 }
 581
 582 static ssize_t
 583 css_cm_enable_show(struct device *dev, struct device_attribute *attr,
 584                    char *buf)
 585 {
 586         struct channel_subsystem *css = to_css(dev);
 587
 588         if (!css)
 589                 return 0;
 590         return sprintf(buf, "%x\n", css->cm_enabled);
 591 }
 592
 593 static ssize_t
 594 css_cm_enable_store(struct device *dev, struct device_attribute *attr,
 595                     const char *buf, size_t count)
 596 {
 597         struct channel_subsystem *css = to_css(dev);
 598         int ret;
 599
 600         switch (buf[0]) {
 601         case '0':
 602                 ret = css->cm_enabled ? chsc_secm(css, 0) : 0;
 603                 break;
 604         case '1':
 605                 ret = css->cm_enabled ? 0 : chsc_secm(css, 1);
 606                 break;
 607         default:
 608                 ret = -EINVAL;
 609         }
 610         return ret < 0 ? ret : count;
 611 }
 612
 613 static DEVICE_ATTR(cm_enable, 0644, css_cm_enable_show, css_cm_enable_store);
 614
 615 static int __init setup_css(int nr)
 616 {
 617         u32 tod_high;
 618         int ret;
 619         struct channel_subsystem *css;
 620
 621         css = channel_subsystems[nr];
 622         memset(css, 0, sizeof(struct channel_subsystem));
 623         css->pseudo_subchannel =
 624                 kzalloc(sizeof(*css->pseudo_subchannel), GFP_KERNEL);
 625         if (!css->pseudo_subchannel)
 626                 return -ENOMEM;
 627         css->pseudo_subchannel->dev.parent = &css->device;
 628         css->pseudo_subchannel->dev.release = css_subchannel_release;
 629         sprintf(css->pseudo_subchannel->dev.bus_id, "defunct");
 630         ret = cio_create_sch_lock(css->pseudo_subchannel);
 631         if (ret) {
 632                 kfree(css->pseudo_subchannel);
 633                 return ret;
 634         }
 635         mutex_init(&css->mutex);
 636         css->valid = 1;
 637         css->cssid = nr;
 638         sprintf(css->device.bus_id, "css%x", nr);
 639         css->device.release = channel_subsystem_release;
 640         tod_high = (u32) (get_clock() >> 32);
 641         css_generate_pgid(css, tod_high);
 642         return 0;
 643 }
 644
 645 static int css_reboot_event(struct notifier_block *this,
 646                             unsigned long event,
 647                             void *ptr)
 648 {
 649         int ret, i;
 650
 651         ret = NOTIFY_DONE;
 652         for (i = 0; i <= __MAX_CSSID; i++) {
 653                 struct channel_subsystem *css;
 654
 655                 css = channel_subsystems[i];
 656                 if (css->cm_enabled)
 657                         if (chsc_secm(css, 0))
 658                                 ret = NOTIFY_BAD;
 659         }
 660
 661         return ret;
 662 }
 663
 664 static struct notifier_block css_reboot_notifier = {
 665         .notifier_call = css_reboot_event,
 666 };
 667
 668 /*
 669  * Now that the driver core is running, we can setup our channel subsystem.
 670  * The struct subchannel's are created during probing (except for the
 671  * static console subchannel).
 672  */
 673 static int __init
 674 init_channel_subsystem (void)
 675 {
 676         int ret, i;
 677
 678         ret = chsc_determine_css_characteristics();
 679         if (ret == -ENOMEM)
 680                 goto out; /* No need to continue. */
 681         if (ret == 0)
 682                 css_characteristics_avail = 1;
 683
 684         ret = chsc_alloc_sei_area();
 685         if (ret)
 686                 goto out;
 687
 688         ret = slow_subchannel_init();
 689         if (ret)
 690                 goto out;
 691
 692         if ((ret = bus_register(&css_bus_type)))
 693                 goto out;
 694
 695         /* Try to enable MSS. */
 696         ret = chsc_enable_facility(CHSC_SDA_OC_MSS);
 697         switch (ret) {
 698         case 0: /* Success. */
 699                 max_ssid = __MAX_SSID;
 700                 break;
 701         case -ENOMEM:
 702                 goto out_bus;
 703         default:
 704                 max_ssid = 0;
 705         }
 706         /* Setup css structure. */
 707         for (i = 0; i <= __MAX_CSSID; i++) {
 708                 struct channel_subsystem *css;
 709
 710                 css = kmalloc(sizeof(struct channel_subsystem), GFP_KERNEL);
 711                 if (!css) {
 712                         ret = -ENOMEM;
 713                         goto out_unregister;
 714                 }
 715                 channel_subsystems[i] = css;
 716                 ret = setup_css(i);
 717                 if (ret)
 718                         goto out_free;
 719                 ret = device_register(&css->device);
 720                 if (ret)
 721                         goto out_free_all;
 722                 if (css_characteristics_avail &&
 723                     css_chsc_characteristics.secm) {
 724                         ret = device_create_file(&css->device,
 725                                                  &dev_attr_cm_enable);
 726                         if (ret)
 727                                 goto out_device;
 728                 }
 729                 ret = device_register(&css->pseudo_subchannel->dev);
 730                 if (ret)
 731                         goto out_file;
 732         }
 733         ret = register_reboot_notifier(&css_reboot_notifier);
 734         if (ret)
 735                 goto out_pseudo;
 736         css_init_done = 1;
 737
 738         ctl_set_bit(6, 28);
 739
 740         for_each_subchannel(__init_channel_subsystem, NULL);
 741         return 0;
 742 out_pseudo:
 743         device_unregister(&channel_subsystems[i]->pseudo_subchannel->dev);
 744 out_file:
 745         device_remove_file(&channel_subsystems[i]->device,
 746                            &dev_attr_cm_enable);
 747 out_device:
 748         device_unregister(&channel_subsystems[i]->device);
 749 out_free_all:
 750         kfree(channel_subsystems[i]->pseudo_subchannel->lock);
 751         kfree(channel_subsystems[i]->pseudo_subchannel);
 752 out_free:
 753         kfree(channel_subsystems[i]);
 754 out_unregister:
 755         while (i > 0) {
 756                 struct channel_subsystem *css;
 757
 758                 i--;
 759                 css = channel_subsystems[i];
 760                 device_unregister(&css->pseudo_subchannel->dev);
 761                 if (css_characteristics_avail && css_chsc_characteristics.secm)
 762                         device_remove_file(&css->device,
 763                                            &dev_attr_cm_enable);
 764                 device_unregister(&css->device);
 765         }
 766 out_bus:
 767         bus_unregister(&css_bus_type);
 768 out:
 769         chsc_free_sei_area();
 770         kfree(slow_subchannel_set);
 771         printk(KERN_WARNING"cio: failed to initialize css driver (%d)!\n",
 772                ret);
 773         return ret;
 774 }
 775
 776 int sch_is_pseudo_sch(struct subchannel *sch)
 777 {
 778         return sch == to_css(sch->dev.parent)->pseudo_subchannel;
 779 }
 780
 781 /*
 782  * find a driver for a subchannel. They identify by the subchannel
 783  * type with the exception that the console subchannel driver has its own
 784  * subchannel type although the device is an i/o subchannel
 785  */
 786 static int
 787 css_bus_match (struct device *dev, struct device_driver *drv)
 788 {
 789         struct subchannel *sch = container_of (dev, struct subchannel, dev);
 790         struct css_driver *driver = container_of (drv, struct css_driver, drv);
 791
 792         if (sch->st == driver->subchannel_type)
 793                 return 1;
 794
 795         return 0;
 796 }
 797
 798 static int
 799 css_probe (struct device *dev)
 800 {
 801         struct subchannel *sch;
 802
 803         sch = to_subchannel(dev);
 804         sch->driver = container_of (dev->driver, struct css_driver, drv);
 805         return (sch->driver->probe ? sch->driver->probe(sch) : 0);
 806 }
 807
 808 static int
 809 css_remove (struct device *dev)
 810 {
 811         struct subchannel *sch;
 812
 813         sch = to_subchannel(dev);
 814         return (sch->driver->remove ? sch->driver->remove(sch) : 0);
 815 }
 816
 817 static void
 818 css_shutdown (struct device *dev)
 819 {
 820         struct subchannel *sch;
 821
 822         sch = to_subchannel(dev);
 823         if (sch->driver->shutdown)
 824                 sch->driver->shutdown(sch);
 825 }
 826
 827 struct bus_type css_bus_type = {
 828         .name     = "css",
 829         .match    = css_bus_match,
 830         .probe    = css_probe,
 831         .remove   = css_remove,
 832         .shutdown = css_shutdown,
 833 };
 834
 835 subsys_initcall(init_channel_subsystem);
 836
 837 MODULE_LICENSE("GPL");
 838 EXPORT_SYMBOL(css_bus_type);
 839 EXPORT_SYMBOL_GPL(css_characteristics_avail);