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);
  83                 return ERR_PTR(ret);
  84         }
  85         return sch;
  86 }
  87
  88 static void
  89 css_free_subchannel(struct subchannel *sch)
  90 {
  91         if (sch) {
  92                 /* Reset intparm to zeroes. */
  93                 sch->schib.pmcw.intparm = 0;
  94                 cio_modify(sch);
  95                 kfree(sch->lock);
  96                 kfree(sch);
  97         }
  98 }
  99
 100 static void
 101 css_subchannel_release(struct device *dev)
 102 {
 103         struct subchannel *sch;
 104
 105         sch = to_subchannel(dev);
 106         if (!cio_is_console(sch->schid)) {
 107                 kfree(sch->lock);
 108                 kfree(sch);
 109         }
 110 }
 111
 112 int css_sch_device_register(struct subchannel *sch)
 113 {
 114         int ret;
 115
 116         mutex_lock(&sch->reg_mutex);
 117         ret = device_register(&sch->dev);
 118         mutex_unlock(&sch->reg_mutex);
 119         return ret;
 120 }
 121
 122 void css_sch_device_unregister(struct subchannel *sch)
 123 {
 124         mutex_lock(&sch->reg_mutex);
 125         device_unregister(&sch->dev);
 126         mutex_unlock(&sch->reg_mutex);
 127 }
 128
 129 static void ssd_from_pmcw(struct chsc_ssd_info *ssd, struct pmcw *pmcw)
 130 {
 131         int i;
 132         int mask;
 133
 134         memset(ssd, 0, sizeof(struct chsc_ssd_info));
 135         ssd->path_mask = pmcw->pim;
 136         for (i = 0; i < 8; i++) {
 137                 mask = 0x80 >> i;
 138                 if (pmcw->pim & mask) {
 139                         chp_id_init(&ssd->chpid[i]);
 140                         ssd->chpid[i].id = pmcw->chpid[i];
 141                 }
 142         }
 143 }
 144
 145 static void ssd_register_chpids(struct chsc_ssd_info *ssd)
 146 {
 147         int i;
 148         int mask;
 149
 150         for (i = 0; i < 8; i++) {
 151                 mask = 0x80 >> i;
 152                 if (ssd->path_mask & mask)
 153                         if (!chp_is_registered(ssd->chpid[i]))
 154                                 chp_new(ssd->chpid[i]);
 155         }
 156 }
 157
 158 void css_update_ssd_info(struct subchannel *sch)
 159 {
 160         int ret;
 161
 162         if (cio_is_console(sch->schid)) {
 163                 /* Console is initialized too early for functions requiring
 164                  * memory allocation. */
 165                 ssd_from_pmcw(&sch->ssd_info, &sch->schib.pmcw);
 166         } else {
 167                 ret = chsc_get_ssd_info(sch->schid, &sch->ssd_info);
 168                 if (ret)
 169                         ssd_from_pmcw(&sch->ssd_info, &sch->schib.pmcw);
 170                 ssd_register_chpids(&sch->ssd_info);
 171         }
 172 }
 173
 174 static int css_register_subchannel(struct subchannel *sch)
 175 {
 176         int ret;
 177
 178         /* Initialize the subchannel structure */
 179         sch->dev.parent = &css[0]->device;
 180         sch->dev.bus = &css_bus_type;
 181         sch->dev.release = &css_subchannel_release;
 182         sch->dev.groups = subch_attr_groups;
 183         css_update_ssd_info(sch);
 184         /* make it known to the system */
 185         ret = css_sch_device_register(sch);
 186         if (ret) {
 187                 printk (KERN_WARNING "%s: could not register %s\n",
 188                         __func__, sch->dev.bus_id);
 189                 return ret;
 190         }
 191         return ret;
 192 }
 193
 194 int
 195 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                 printk(KERN_WARNING "cio: could not allocate slow subchannel "
 376                        "set\n");
 377                 return -ENOMEM;
 378         }
 379         return 0;
 380 }
 381
 382 subsys_initcall(slow_subchannel_init);
 383
 384 static void css_slow_path_func(struct work_struct *unused)
 385 {
 386         struct subchannel_id schid;
 387
 388         CIO_TRACE_EVENT(4, "slowpath");
 389         spin_lock_irq(&slow_subchannel_lock);
 390         init_subchannel_id(&schid);
 391         while (idset_sch_get_first(slow_subchannel_set, &schid)) {
 392                 idset_sch_del(slow_subchannel_set, schid);
 393                 spin_unlock_irq(&slow_subchannel_lock);
 394                 css_evaluate_subchannel(schid, 1);
 395                 spin_lock_irq(&slow_subchannel_lock);
 396         }
 397         spin_unlock_irq(&slow_subchannel_lock);
 398 }
 399
 400 static DECLARE_WORK(slow_path_work, css_slow_path_func);
 401 struct workqueue_struct *slow_path_wq;
 402
 403 void css_schedule_eval(struct subchannel_id schid)
 404 {
 405         unsigned long flags;
 406
 407         spin_lock_irqsave(&slow_subchannel_lock, flags);
 408         idset_sch_add(slow_subchannel_set, schid);
 409         queue_work(slow_path_wq, &slow_path_work);
 410         spin_unlock_irqrestore(&slow_subchannel_lock, flags);
 411 }
 412
 413 void css_schedule_eval_all(void)
 414 {
 415         unsigned long flags;
 416
 417         spin_lock_irqsave(&slow_subchannel_lock, flags);
 418         idset_fill(slow_subchannel_set);
 419         queue_work(slow_path_wq, &slow_path_work);
 420         spin_unlock_irqrestore(&slow_subchannel_lock, flags);
 421 }
 422
 423 /* Reprobe subchannel if unregistered. */
 424 static int reprobe_subchannel(struct subchannel_id schid, void *data)
 425 {
 426         struct subchannel *sch;
 427         int ret;
 428
 429         CIO_DEBUG(KERN_INFO, 6, "cio: reprobe 0.%x.%04x\n",
 430                   schid.ssid, schid.sch_no);
 431         if (need_reprobe)
 432                 return -EAGAIN;
 433
 434         sch = get_subchannel_by_schid(schid);
 435         if (sch) {
 436                 /* Already known. */
 437                 put_device(&sch->dev);
 438                 return 0;
 439         }
 440
 441         ret = css_probe_device(schid);
 442         switch (ret) {
 443         case 0:
 444                 break;
 445         case -ENXIO:
 446         case -ENOMEM:
 447                 /* These should abort looping */
 448                 break;
 449         default:
 450                 ret = 0;
 451         }
 452
 453         return ret;
 454 }
 455
 456 /* Work function used to reprobe all unregistered subchannels. */
 457 static void reprobe_all(struct work_struct *unused)
 458 {
 459         int ret;
 460
 461         CIO_MSG_EVENT(2, "reprobe start\n");
 462
 463         need_reprobe = 0;
 464         /* Make sure initial subchannel scan is done. */
 465         wait_event(ccw_device_init_wq,
 466                    atomic_read(&ccw_device_init_count) == 0);
 467         ret = for_each_subchannel(reprobe_subchannel, NULL);
 468
 469         CIO_MSG_EVENT(2, "reprobe done (rc=%d, need_reprobe=%d)\n", ret,
 470                       need_reprobe);
 471 }
 472
 473 static DECLARE_WORK(css_reprobe_work, reprobe_all);
 474
 475 /* Schedule reprobing of all unregistered subchannels. */
 476 void css_schedule_reprobe(void)
 477 {
 478         need_reprobe = 1;
 479         queue_work(ccw_device_work, &css_reprobe_work);
 480 }
 481
 482 EXPORT_SYMBOL_GPL(css_schedule_reprobe);
 483
 484 /*
 485  * Called from the machine check handler for subchannel report words.
 486  */
 487 void css_process_crw(int rsid1, int rsid2)
 488 {
 489         struct subchannel_id mchk_schid;
 490
 491         CIO_CRW_EVENT(2, "source is subchannel %04X, subsystem id %x\n",
 492                       rsid1, rsid2);
 493         init_subchannel_id(&mchk_schid);
 494         mchk_schid.sch_no = rsid1;
 495         if (rsid2 != 0)
 496                 mchk_schid.ssid = (rsid2 >> 8) & 3;
 497
 498         /*
 499          * Since we are always presented with IPI in the CRW, we have to
 500          * use stsch() to find out if the subchannel in question has come
 501          * or gone.
 502          */
 503         css_evaluate_subchannel(mchk_schid, 0);
 504 }
 505
 506 static int __init
 507 __init_channel_subsystem(struct subchannel_id schid, void *data)
 508 {
 509         struct subchannel *sch;
 510         int ret;
 511
 512         if (cio_is_console(schid))
 513                 sch = cio_get_console_subchannel();
 514         else {
 515                 sch = css_alloc_subchannel(schid);
 516                 if (IS_ERR(sch))
 517                         ret = PTR_ERR(sch);
 518                 else
 519                         ret = 0;
 520                 switch (ret) {
 521                 case 0:
 522                         break;
 523                 case -ENOMEM:
 524                         panic("Out of memory in init_channel_subsystem\n");
 525                 /* -ENXIO: no more subchannels. */
 526                 case -ENXIO:
 527                         return ret;
 528                 /* -EIO: this subchannel set not supported. */
 529                 case -EIO:
 530                         return ret;
 531                 default:
 532                         return 0;
 533                 }
 534         }
 535         /*
 536          * We register ALL valid subchannels in ioinfo, even those
 537          * that have been present before init_channel_subsystem.
 538          * These subchannels can't have been registered yet (kmalloc
 539          * not working) so we do it now. This is true e.g. for the
 540          * console subchannel.
 541          */
 542         css_register_subchannel(sch);
 543         return 0;
 544 }
 545
 546 static void __init
 547 css_generate_pgid(struct channel_subsystem *css, u32 tod_high)
 548 {
 549         if (css_characteristics_avail && css_general_characteristics.mcss) {
 550                 css->global_pgid.pgid_high.ext_cssid.version = 0x80;
 551                 css->global_pgid.pgid_high.ext_cssid.cssid = css->cssid;
 552         } else {
 553 #ifdef CONFIG_SMP
 554                 css->global_pgid.pgid_high.cpu_addr = hard_smp_processor_id();
 555 #else
 556                 css->global_pgid.pgid_high.cpu_addr = 0;
 557 #endif
 558         }
 559         css->global_pgid.cpu_id = ((cpuid_t *) __LC_CPUID)->ident;
 560         css->global_pgid.cpu_model = ((cpuid_t *) __LC_CPUID)->machine;
 561         css->global_pgid.tod_high = tod_high;
 562
 563 }
 564
 565 static void
 566 channel_subsystem_release(struct device *dev)
 567 {
 568         struct channel_subsystem *css;
 569
 570         css = to_css(dev);
 571         mutex_destroy(&css->mutex);
 572         kfree(css);
 573 }
 574
 575 static ssize_t
 576 css_cm_enable_show(struct device *dev, struct device_attribute *attr,
 577                    char *buf)
 578 {
 579         struct channel_subsystem *css = to_css(dev);
 580
 581         if (!css)
 582                 return 0;
 583         return sprintf(buf, "%x\n", css->cm_enabled);
 584 }
 585
 586 static ssize_t
 587 css_cm_enable_store(struct device *dev, struct device_attribute *attr,
 588                     const char *buf, size_t count)
 589 {
 590         struct channel_subsystem *css = to_css(dev);
 591         int ret;
 592
 593         switch (buf[0]) {
 594         case '0':
 595                 ret = css->cm_enabled ? chsc_secm(css, 0) : 0;
 596                 break;
 597         case '1':
 598                 ret = css->cm_enabled ? 0 : chsc_secm(css, 1);
 599                 break;
 600         default:
 601                 ret = -EINVAL;
 602         }
 603         return ret < 0 ? ret : count;
 604 }
 605
 606 static DEVICE_ATTR(cm_enable, 0644, css_cm_enable_show, css_cm_enable_store);
 607
 608 static int __init setup_css(int nr)
 609 {
 610         u32 tod_high;
 611         int ret;
 612
 613         memset(css[nr], 0, sizeof(struct channel_subsystem));
 614         css[nr]->pseudo_subchannel =
 615                 kzalloc(sizeof(*css[nr]->pseudo_subchannel), GFP_KERNEL);
 616         if (!css[nr]->pseudo_subchannel)
 617                 return -ENOMEM;
 618         css[nr]->pseudo_subchannel->dev.parent = &css[nr]->device;
 619         css[nr]->pseudo_subchannel->dev.release = css_subchannel_release;
 620         sprintf(css[nr]->pseudo_subchannel->dev.bus_id, "defunct");
 621         ret = cio_create_sch_lock(css[nr]->pseudo_subchannel);
 622         if (ret) {
 623                 kfree(css[nr]->pseudo_subchannel);
 624                 return ret;
 625         }
 626         mutex_init(&css[nr]->mutex);
 627         css[nr]->valid = 1;
 628         css[nr]->cssid = nr;
 629         sprintf(css[nr]->device.bus_id, "css%x", nr);
 630         css[nr]->device.release = channel_subsystem_release;
 631         tod_high = (u32) (get_clock() >> 32);
 632         css_generate_pgid(css[nr], tod_high);
 633         return 0;
 634 }
 635
 636 /*
 637  * Now that the driver core is running, we can setup our channel subsystem.
 638  * The struct subchannel's are created during probing (except for the
 639  * static console subchannel).
 640  */
 641 static int __init
 642 init_channel_subsystem (void)
 643 {
 644         int ret, i;
 645
 646         if (chsc_determine_css_characteristics() == 0)
 647                 css_characteristics_avail = 1;
 648
 649         if ((ret = bus_register(&css_bus_type)))
 650                 goto out;
 651
 652         /* Try to enable MSS. */
 653         ret = chsc_enable_facility(CHSC_SDA_OC_MSS);
 654         switch (ret) {
 655         case 0: /* Success. */
 656                 max_ssid = __MAX_SSID;
 657                 break;
 658         case -ENOMEM:
 659                 goto out_bus;
 660         default:
 661                 max_ssid = 0;
 662         }
 663         /* Setup css structure. */
 664         for (i = 0; i <= __MAX_CSSID; i++) {
 665                 css[i] = kmalloc(sizeof(struct channel_subsystem), GFP_KERNEL);
 666                 if (!css[i]) {
 667                         ret = -ENOMEM;
 668                         goto out_unregister;
 669                 }
 670                 ret = setup_css(i);
 671                 if (ret)
 672                         goto out_free;
 673                 ret = device_register(&css[i]->device);
 674                 if (ret)
 675                         goto out_free_all;
 676                 if (css_characteristics_avail &&
 677                     css_chsc_characteristics.secm) {
 678                         ret = device_create_file(&css[i]->device,
 679                                                  &dev_attr_cm_enable);
 680                         if (ret)
 681                                 goto out_device;
 682                 }
 683                 ret = device_register(&css[i]->pseudo_subchannel->dev);
 684                 if (ret)
 685                         goto out_file;
 686         }
 687         css_init_done = 1;
 688
 689         ctl_set_bit(6, 28);
 690
 691         for_each_subchannel(__init_channel_subsystem, NULL);
 692         return 0;
 693 out_file:
 694         device_remove_file(&css[i]->device, &dev_attr_cm_enable);
 695 out_device:
 696         device_unregister(&css[i]->device);
 697 out_free_all:
 698         kfree(css[i]->pseudo_subchannel->lock);
 699         kfree(css[i]->pseudo_subchannel);
 700 out_free:
 701         kfree(css[i]);
 702 out_unregister:
 703         while (i > 0) {
 704                 i--;
 705                 device_unregister(&css[i]->pseudo_subchannel->dev);
 706                 if (css_characteristics_avail && css_chsc_characteristics.secm)
 707                         device_remove_file(&css[i]->device,
 708                                            &dev_attr_cm_enable);
 709                 device_unregister(&css[i]->device);
 710         }
 711 out_bus:
 712         bus_unregister(&css_bus_type);
 713 out:
 714         return ret;
 715 }
 716
 717 int sch_is_pseudo_sch(struct subchannel *sch)
 718 {
 719         return sch == to_css(sch->dev.parent)->pseudo_subchannel;
 720 }
 721
 722 /*
 723  * find a driver for a subchannel. They identify by the subchannel
 724  * type with the exception that the console subchannel driver has its own
 725  * subchannel type although the device is an i/o subchannel
 726  */
 727 static int
 728 css_bus_match (struct device *dev, struct device_driver *drv)
 729 {
 730         struct subchannel *sch = container_of (dev, struct subchannel, dev);
 731         struct css_driver *driver = container_of (drv, struct css_driver, drv);
 732
 733         if (sch->st == driver->subchannel_type)
 734                 return 1;
 735
 736         return 0;
 737 }
 738
 739 static int
 740 css_probe (struct device *dev)
 741 {
 742         struct subchannel *sch;
 743
 744         sch = to_subchannel(dev);
 745         sch->driver = container_of (dev->driver, struct css_driver, drv);
 746         return (sch->driver->probe ? sch->driver->probe(sch) : 0);
 747 }
 748
 749 static int
 750 css_remove (struct device *dev)
 751 {
 752         struct subchannel *sch;
 753
 754         sch = to_subchannel(dev);
 755         return (sch->driver->remove ? sch->driver->remove(sch) : 0);
 756 }
 757
 758 static void
 759 css_shutdown (struct device *dev)
 760 {
 761         struct subchannel *sch;
 762
 763         sch = to_subchannel(dev);
 764         if (sch->driver->shutdown)
 765                 sch->driver->shutdown(sch);
 766 }
 767
 768 struct bus_type css_bus_type = {
 769         .name     = "css",
 770         .match    = css_bus_match,
 771         .probe    = css_probe,
 772         .remove   = css_remove,
 773         .shutdown = css_shutdown,
 774 };
 775
 776 subsys_initcall(init_channel_subsystem);
 777
 778 MODULE_LICENSE("GPL");
 779 EXPORT_SYMBOL(css_bus_type);
 780 EXPORT_SYMBOL_GPL(css_characteristics_avail);