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