git.oblomov.eu Git - linux-2.6/blob - 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 struct cb_data {
  55         void *data;
  56         struct idset *set;
  57         int (*fn_known_sch)(struct subchannel *, void *);
  58         int (*fn_unknown_sch)(struct subchannel_id, void *);
  59 };
  60
  61 static int call_fn_known_sch(struct device *dev, void *data)
  62 {
  63         struct subchannel *sch = to_subchannel(dev);
  64         struct cb_data *cb = data;
  65         int rc = 0;
  66
  67         idset_sch_del(cb->set, sch->schid);
  68         if (cb->fn_known_sch)
  69                 rc = cb->fn_known_sch(sch, cb->data);
  70         return rc;
  71 }
  72
  73 static int call_fn_unknown_sch(struct subchannel_id schid, void *data)
  74 {
  75         struct cb_data *cb = data;
  76         int rc = 0;
  77
  78         if (idset_sch_contains(cb->set, schid))
  79                 rc = cb->fn_unknown_sch(schid, cb->data);
  80         return rc;
  81 }
  82
  83 int for_each_subchannel_staged(int (*fn_known)(struct subchannel *, void *),
  84                                int (*fn_unknown)(struct subchannel_id,
  85                                void *), void *data)
  86 {
  87         struct cb_data cb;
  88         int rc;
  89
  90         cb.set = idset_sch_new();
  91         if (!cb.set)
  92                 return -ENOMEM;
  93         idset_fill(cb.set);
  94         cb.data = data;
  95         cb.fn_known_sch = fn_known;
  96         cb.fn_unknown_sch = fn_unknown;
  97         /* Process registered subchannels. */
  98         rc = bus_for_each_dev(&css_bus_type, NULL, &cb, call_fn_known_sch);
  99         if (rc)
 100                 goto out;
 101         /* Process unregistered subchannels. */
 102         if (fn_unknown)
 103                 rc = for_each_subchannel(call_fn_unknown_sch, &cb);
 104 out:
 105         idset_free(cb.set);
 106
 107         return rc;
 108 }
 109
 110 static struct subchannel *
 111 css_alloc_subchannel(struct subchannel_id schid)
 112 {
 113         struct subchannel *sch;
 114         int ret;
 115
 116         sch = kmalloc (sizeof (*sch), GFP_KERNEL | GFP_DMA);
 117         if (sch == NULL)
 118                 return ERR_PTR(-ENOMEM);
 119         ret = cio_validate_subchannel (sch, schid);
 120         if (ret < 0) {
 121                 kfree(sch);
 122                 return ERR_PTR(ret);
 123         }
 124
 125         if (sch->st != SUBCHANNEL_TYPE_IO) {
 126                 /* For now we ignore all non-io subchannels. */
 127                 kfree(sch);
 128                 return ERR_PTR(-EINVAL);
 129         }
 130
 131         /*
 132          * Set intparm to subchannel address.
 133          * This is fine even on 64bit since the subchannel is always located
 134          * under 2G.
 135          */
 136         sch->schib.pmcw.intparm = (u32)(addr_t)sch;
 137         ret = cio_modify(sch);
 138         if (ret) {
 139                 kfree(sch->lock);
 140                 kfree(sch);
 141                 return ERR_PTR(ret);
 142         }
 143         return sch;
 144 }
 145
 146 static void
 147 css_free_subchannel(struct subchannel *sch)
 148 {
 149         if (sch) {
 150                 /* Reset intparm to zeroes. */
 151                 sch->schib.pmcw.intparm = 0;
 152                 cio_modify(sch);
 153                 kfree(sch->lock);
 154                 kfree(sch);
 155         }
 156 }
 157
 158 static void
 159 css_subchannel_release(struct device *dev)
 160 {
 161         struct subchannel *sch;
 162
 163         sch = to_subchannel(dev);
 164         if (!cio_is_console(sch->schid)) {
 165                 kfree(sch->lock);
 166                 kfree(sch);
 167         }
 168 }
 169
 170 static int css_sch_device_register(struct subchannel *sch)
 171 {
 172         int ret;
 173
 174         mutex_lock(&sch->reg_mutex);
 175         ret = device_register(&sch->dev);
 176         mutex_unlock(&sch->reg_mutex);
 177         return ret;
 178 }
 179
 180 void css_sch_device_unregister(struct subchannel *sch)
 181 {
 182         mutex_lock(&sch->reg_mutex);
 183         device_unregister(&sch->dev);
 184         mutex_unlock(&sch->reg_mutex);
 185 }
 186
 187 static void ssd_from_pmcw(struct chsc_ssd_info *ssd, struct pmcw *pmcw)
 188 {
 189         int i;
 190         int mask;
 191
 192         memset(ssd, 0, sizeof(struct chsc_ssd_info));
 193         ssd->path_mask = pmcw->pim;
 194         for (i = 0; i < 8; i++) {
 195                 mask = 0x80 >> i;
 196                 if (pmcw->pim & mask) {
 197                         chp_id_init(&ssd->chpid[i]);
 198                         ssd->chpid[i].id = pmcw->chpid[i];
 199                 }
 200         }
 201 }
 202
 203 static void ssd_register_chpids(struct chsc_ssd_info *ssd)
 204 {
 205         int i;
 206         int mask;
 207
 208         for (i = 0; i < 8; i++) {
 209                 mask = 0x80 >> i;
 210                 if (ssd->path_mask & mask)
 211                         if (!chp_is_registered(ssd->chpid[i]))
 212                                 chp_new(ssd->chpid[i]);
 213         }
 214 }
 215
 216 void css_update_ssd_info(struct subchannel *sch)
 217 {
 218         int ret;
 219
 220         if (cio_is_console(sch->schid)) {
 221                 /* Console is initialized too early for functions requiring
 222                  * memory allocation. */
 223                 ssd_from_pmcw(&sch->ssd_info, &sch->schib.pmcw);
 224         } else {
 225                 ret = chsc_get_ssd_info(sch->schid, &sch->ssd_info);
 226                 if (ret)
 227                         ssd_from_pmcw(&sch->ssd_info, &sch->schib.pmcw);
 228                 ssd_register_chpids(&sch->ssd_info);
 229         }
 230 }
 231
 232 static int css_register_subchannel(struct subchannel *sch)
 233 {
 234         int ret;
 235
 236         /* Initialize the subchannel structure */
 237         sch->dev.parent = &channel_subsystems[0]->device;
 238         sch->dev.bus = &css_bus_type;
 239         sch->dev.release = &css_subchannel_release;
 240         sch->dev.groups = subch_attr_groups;
 241         /*
 242          * We don't want to generate uevents for I/O subchannels that don't
 243          * have a working ccw device behind them since they will be
 244          * unregistered before they can be used anyway, so we delay the add
 245          * uevent until after device recognition was successful.
 246          */
 247         if (!cio_is_console(sch->schid))
 248                 /* Console is special, no need to suppress. */
 249                 sch->dev.uevent_suppress = 1;
 250         css_update_ssd_info(sch);
 251         /* make it known to the system */
 252         ret = css_sch_device_register(sch);
 253         if (ret) {
 254                 CIO_MSG_EVENT(0, "Could not register sch 0.%x.%04x: %d\n",
 255                               sch->schid.ssid, sch->schid.sch_no, ret);
 256                 return ret;
 257         }
 258         return ret;
 259 }
 260
 261 static int css_probe_device(struct subchannel_id schid)
 262 {
 263         int ret;
 264         struct subchannel *sch;
 265
 266         sch = css_alloc_subchannel(schid);
 267         if (IS_ERR(sch))
 268                 return PTR_ERR(sch);
 269         ret = css_register_subchannel(sch);
 270         if (ret)
 271                 css_free_subchannel(sch);
 272         return ret;
 273 }
 274
 275 static int
 276 check_subchannel(struct device * dev, void * data)
 277 {
 278         struct subchannel *sch;
 279         struct subchannel_id *schid = data;
 280
 281         sch = to_subchannel(dev);
 282         return schid_equal(&sch->schid, schid);
 283 }
 284
 285 struct subchannel *
 286 get_subchannel_by_schid(struct subchannel_id schid)
 287 {
 288         struct device *dev;
 289
 290         dev = bus_find_device(&css_bus_type, NULL,
 291                               &schid, check_subchannel);
 292
 293         return dev ? to_subchannel(dev) : NULL;
 294 }
 295
 296 /**
 297  * css_sch_is_valid() - check if a subchannel is valid
 298  * @schib: subchannel information block for the subchannel
 299  */
 300 int css_sch_is_valid(struct schib *schib)
 301 {
 302         if ((schib->pmcw.st == SUBCHANNEL_TYPE_IO) && !schib->pmcw.dnv)
 303                 return 0;
 304         return 1;
 305 }
 306 EXPORT_SYMBOL_GPL(css_sch_is_valid);
 307
 308 static int css_get_subchannel_status(struct subchannel *sch)
 309 {
 310         struct schib schib;
 311
 312         if (stsch(sch->schid, &schib))
 313                 return CIO_GONE;
 314         if (!css_sch_is_valid(&schib))
 315                 return CIO_GONE;
 316         if (sch->schib.pmcw.dnv && (schib.pmcw.dev != sch->schib.pmcw.dev))
 317                 return CIO_REVALIDATE;
 318         if (!sch->lpm)
 319                 return CIO_NO_PATH;
 320         return CIO_OPER;
 321 }
 322
 323 static int css_evaluate_known_subchannel(struct subchannel *sch, int slow)
 324 {
 325         int event, ret, disc;
 326         unsigned long flags;
 327         enum { NONE, UNREGISTER, UNREGISTER_PROBE, REPROBE } action;
 328
 329         spin_lock_irqsave(sch->lock, flags);
 330         disc = device_is_disconnected(sch);
 331         if (disc && slow) {
 332                 /* Disconnected devices are evaluated directly only.*/
 333                 spin_unlock_irqrestore(sch->lock, flags);
 334                 return 0;
 335         }
 336         /* No interrupt after machine check - kill pending timers. */
 337         device_kill_pending_timer(sch);
 338         if (!disc && !slow) {
 339                 /* Non-disconnected devices are evaluated on the slow path. */
 340                 spin_unlock_irqrestore(sch->lock, flags);
 341                 return -EAGAIN;
 342         }
 343         event = css_get_subchannel_status(sch);
 344         CIO_MSG_EVENT(4, "Evaluating schid 0.%x.%04x, event %d, %s, %s path.\n",
 345                       sch->schid.ssid, sch->schid.sch_no, event,
 346                       disc ? "disconnected" : "normal",
 347                       slow ? "slow" : "fast");
 348         /* Analyze subchannel status. */
 349         action = NONE;
 350         switch (event) {
 351         case CIO_NO_PATH:
 352                 if (disc) {
 353                         /* Check if paths have become available. */
 354                         action = REPROBE;
 355                         break;
 356                 }
 357                 /* fall through */
 358         case CIO_GONE:
 359                 /* Prevent unwanted effects when opening lock. */
 360                 cio_disable_subchannel(sch);
 361                 device_set_disconnected(sch);
 362                 /* Ask driver what to do with device. */
 363                 action = UNREGISTER;
 364                 if (sch->driver && sch->driver->notify) {
 365                         spin_unlock_irqrestore(sch->lock, flags);
 366                         ret = sch->driver->notify(sch, event);
 367                         spin_lock_irqsave(sch->lock, flags);
 368                         if (ret)
 369                                 action = NONE;
 370                 }
 371                 break;
 372         case CIO_REVALIDATE:
 373                 /* Device will be removed, so no notify necessary. */
 374                 if (disc)
 375                         /* Reprobe because immediate unregister might block. */
 376                         action = REPROBE;
 377                 else
 378                         action = UNREGISTER_PROBE;
 379                 break;
 380         case CIO_OPER:
 381                 if (disc)
 382                         /* Get device operational again. */
 383                         action = REPROBE;
 384                 break;
 385         }
 386         /* Perform action. */
 387         ret = 0;
 388         switch (action) {
 389         case UNREGISTER:
 390         case UNREGISTER_PROBE:
 391                 /* Unregister device (will use subchannel lock). */
 392                 spin_unlock_irqrestore(sch->lock, flags);
 393                 css_sch_device_unregister(sch);
 394                 spin_lock_irqsave(sch->lock, flags);
 395
 396                 /* Reset intparm to zeroes. */
 397                 sch->schib.pmcw.intparm = 0;
 398                 cio_modify(sch);
 399                 break;
 400         case REPROBE:
 401                 device_trigger_reprobe(sch);
 402                 break;
 403         default:
 404                 break;
 405         }
 406         spin_unlock_irqrestore(sch->lock, flags);
 407         /* Probe if necessary. */
 408         if (action == UNREGISTER_PROBE)
 409                 ret = css_probe_device(sch->schid);
 410
 411         return ret;
 412 }
 413
 414 static int css_evaluate_new_subchannel(struct subchannel_id schid, int slow)
 415 {
 416         struct schib schib;
 417
 418         if (!slow) {
 419                 /* Will be done on the slow path. */
 420                 return -EAGAIN;
 421         }
 422         if (stsch_err(schid, &schib) || !css_sch_is_valid(&schib)) {
 423                 /* Unusable - ignore. */
 424                 return 0;
 425         }
 426         CIO_MSG_EVENT(4, "Evaluating schid 0.%x.%04x, event %d, unknown, "
 427                          "slow path.\n", schid.ssid, schid.sch_no, CIO_OPER);
 428
 429         return css_probe_device(schid);
 430 }
 431
 432 static void css_evaluate_subchannel(struct subchannel_id schid, int slow)
 433 {
 434         struct subchannel *sch;
 435         int ret;
 436
 437         sch = get_subchannel_by_schid(schid);
 438         if (sch) {
 439                 ret = css_evaluate_known_subchannel(sch, slow);
 440                 put_device(&sch->dev);
 441         } else
 442                 ret = css_evaluate_new_subchannel(schid, slow);
 443         if (ret == -EAGAIN)
 444                 css_schedule_eval(schid);
 445 }
 446
 447 static struct idset *slow_subchannel_set;
 448 static spinlock_t slow_subchannel_lock;
 449
 450 static int __init slow_subchannel_init(void)
 451 {
 452         spin_lock_init(&slow_subchannel_lock);
 453         slow_subchannel_set = idset_sch_new();
 454         if (!slow_subchannel_set) {
 455                 CIO_MSG_EVENT(0, "could not allocate slow subchannel set\n");
 456                 return -ENOMEM;
 457         }
 458         return 0;
 459 }
 460
 461 static int slow_eval_known_fn(struct subchannel *sch, void *data)
 462 {
 463         int eval;
 464         int rc;
 465
 466         spin_lock_irq(&slow_subchannel_lock);
 467         eval = idset_sch_contains(slow_subchannel_set, sch->schid);
 468         idset_sch_del(slow_subchannel_set, sch->schid);
 469         spin_unlock_irq(&slow_subchannel_lock);
 470         if (eval) {
 471                 rc = css_evaluate_known_subchannel(sch, 1);
 472                 if (rc == -EAGAIN)
 473                         css_schedule_eval(sch->schid);
 474         }
 475         return 0;
 476 }
 477
 478 static int slow_eval_unknown_fn(struct subchannel_id schid, void *data)
 479 {
 480         int eval;
 481         int rc = 0;
 482
 483         spin_lock_irq(&slow_subchannel_lock);
 484         eval = idset_sch_contains(slow_subchannel_set, schid);
 485         idset_sch_del(slow_subchannel_set, schid);
 486         spin_unlock_irq(&slow_subchannel_lock);
 487         if (eval) {
 488                 rc = css_evaluate_new_subchannel(schid, 1);
 489                 switch (rc) {
 490                 case -EAGAIN:
 491                         css_schedule_eval(schid);
 492                         rc = 0;
 493                         break;
 494                 case -ENXIO:
 495                 case -ENOMEM:
 496                 case -EIO:
 497                         /* These should abort looping */
 498                         break;
 499                 default:
 500                         rc = 0;
 501                 }
 502         }
 503         return rc;
 504 }
 505
 506 static void css_slow_path_func(struct work_struct *unused)
 507 {
 508         CIO_TRACE_EVENT(4, "slowpath");
 509         for_each_subchannel_staged(slow_eval_known_fn, slow_eval_unknown_fn,
 510                                    NULL);
 511 }
 512
 513 static DECLARE_WORK(slow_path_work, css_slow_path_func);
 514 struct workqueue_struct *slow_path_wq;
 515
 516 void css_schedule_eval(struct subchannel_id schid)
 517 {
 518         unsigned long flags;
 519
 520         spin_lock_irqsave(&slow_subchannel_lock, flags);
 521         idset_sch_add(slow_subchannel_set, schid);
 522         queue_work(slow_path_wq, &slow_path_work);
 523         spin_unlock_irqrestore(&slow_subchannel_lock, flags);
 524 }
 525
 526 void css_schedule_eval_all(void)
 527 {
 528         unsigned long flags;
 529
 530         spin_lock_irqsave(&slow_subchannel_lock, flags);
 531         idset_fill(slow_subchannel_set);
 532         queue_work(slow_path_wq, &slow_path_work);
 533         spin_unlock_irqrestore(&slow_subchannel_lock, flags);
 534 }
 535
 536 void css_wait_for_slow_path(void)
 537 {
 538         flush_workqueue(ccw_device_notify_work);
 539         flush_workqueue(slow_path_wq);
 540 }
 541
 542 /* Reprobe subchannel if unregistered. */
 543 static int reprobe_subchannel(struct subchannel_id schid, void *data)
 544 {
 545         int ret;
 546
 547         CIO_MSG_EVENT(6, "cio: reprobe 0.%x.%04x\n",
 548                       schid.ssid, schid.sch_no);
 549         if (need_reprobe)
 550                 return -EAGAIN;
 551
 552         ret = css_probe_device(schid);
 553         switch (ret) {
 554         case 0:
 555                 break;
 556         case -ENXIO:
 557         case -ENOMEM:
 558         case -EIO:
 559                 /* These should abort looping */
 560                 break;
 561         default:
 562                 ret = 0;
 563         }
 564
 565         return ret;
 566 }
 567
 568 /* Work function used to reprobe all unregistered subchannels. */
 569 static void reprobe_all(struct work_struct *unused)
 570 {
 571         int ret;
 572
 573         CIO_MSG_EVENT(4, "reprobe start\n");
 574
 575         need_reprobe = 0;
 576         /* Make sure initial subchannel scan is done. */
 577         wait_event(ccw_device_init_wq,
 578                    atomic_read(&ccw_device_init_count) == 0);
 579         ret = for_each_subchannel_staged(NULL, reprobe_subchannel, NULL);
 580
 581         CIO_MSG_EVENT(4, "reprobe done (rc=%d, need_reprobe=%d)\n", ret,
 582                       need_reprobe);
 583 }
 584
 585 static DECLARE_WORK(css_reprobe_work, reprobe_all);
 586
 587 /* Schedule reprobing of all unregistered subchannels. */
 588 void css_schedule_reprobe(void)
 589 {
 590         need_reprobe = 1;
 591         queue_work(slow_path_wq, &css_reprobe_work);
 592 }
 593
 594 EXPORT_SYMBOL_GPL(css_schedule_reprobe);
 595
 596 /*
 597  * Called from the machine check handler for subchannel report words.
 598  */
 599 void css_process_crw(int rsid1, int rsid2)
 600 {
 601         struct subchannel_id mchk_schid;
 602
 603         CIO_CRW_EVENT(2, "source is subchannel %04X, subsystem id %x\n",
 604                       rsid1, rsid2);
 605         init_subchannel_id(&mchk_schid);
 606         mchk_schid.sch_no = rsid1;
 607         if (rsid2 != 0)
 608                 mchk_schid.ssid = (rsid2 >> 8) & 3;
 609
 610         /*
 611          * Since we are always presented with IPI in the CRW, we have to
 612          * use stsch() to find out if the subchannel in question has come
 613          * or gone.
 614          */
 615         css_evaluate_subchannel(mchk_schid, 0);
 616 }
 617
 618 static int __init
 619 __init_channel_subsystem(struct subchannel_id schid, void *data)
 620 {
 621         struct subchannel *sch;
 622         int ret;
 623
 624         if (cio_is_console(schid))
 625                 sch = cio_get_console_subchannel();
 626         else {
 627                 sch = css_alloc_subchannel(schid);
 628                 if (IS_ERR(sch))
 629                         ret = PTR_ERR(sch);
 630                 else
 631                         ret = 0;
 632                 switch (ret) {
 633                 case 0:
 634                         break;
 635                 case -ENOMEM:
 636                         panic("Out of memory in init_channel_subsystem\n");
 637                 /* -ENXIO: no more subchannels. */
 638                 case -ENXIO:
 639                         return ret;
 640                 /* -EIO: this subchannel set not supported. */
 641                 case -EIO:
 642                         return ret;
 643                 default:
 644                         return 0;
 645                 }
 646         }
 647         /*
 648          * We register ALL valid subchannels in ioinfo, even those
 649          * that have been present before init_channel_subsystem.
 650          * These subchannels can't have been registered yet (kmalloc
 651          * not working) so we do it now. This is true e.g. for the
 652          * console subchannel.
 653          */
 654         css_register_subchannel(sch);
 655         return 0;
 656 }
 657
 658 static void __init
 659 css_generate_pgid(struct channel_subsystem *css, u32 tod_high)
 660 {
 661         if (css_characteristics_avail && css_general_characteristics.mcss) {
 662                 css->global_pgid.pgid_high.ext_cssid.version = 0x80;
 663                 css->global_pgid.pgid_high.ext_cssid.cssid = css->cssid;
 664         } else {
 665 #ifdef CONFIG_SMP
 666                 css->global_pgid.pgid_high.cpu_addr = hard_smp_processor_id();
 667 #else
 668                 css->global_pgid.pgid_high.cpu_addr = 0;
 669 #endif
 670         }
 671         css->global_pgid.cpu_id = ((cpuid_t *) __LC_CPUID)->ident;
 672         css->global_pgid.cpu_model = ((cpuid_t *) __LC_CPUID)->machine;
 673         css->global_pgid.tod_high = tod_high;
 674
 675 }
 676
 677 static void
 678 channel_subsystem_release(struct device *dev)
 679 {
 680         struct channel_subsystem *css;
 681
 682         css = to_css(dev);
 683         mutex_destroy(&css->mutex);
 684         kfree(css);
 685 }
 686
 687 static ssize_t
 688 css_cm_enable_show(struct device *dev, struct device_attribute *attr,
 689                    char *buf)
 690 {
 691         struct channel_subsystem *css = to_css(dev);
 692         int ret;
 693
 694         if (!css)
 695                 return 0;
 696         mutex_lock(&css->mutex);
 697         ret = sprintf(buf, "%x\n", css->cm_enabled);
 698         mutex_unlock(&css->mutex);
 699         return ret;
 700 }
 701
 702 static ssize_t
 703 css_cm_enable_store(struct device *dev, struct device_attribute *attr,
 704                     const char *buf, size_t count)
 705 {
 706         struct channel_subsystem *css = to_css(dev);
 707         int ret;
 708         unsigned long val;
 709
 710         ret = strict_strtoul(buf, 16, &val);
 711         if (ret)
 712                 return ret;
 713         mutex_lock(&css->mutex);
 714         switch (val) {
 715         case 0:
 716                 ret = css->cm_enabled ? chsc_secm(css, 0) : 0;
 717                 break;
 718         case 1:
 719                 ret = css->cm_enabled ? 0 : chsc_secm(css, 1);
 720                 break;
 721         default:
 722                 ret = -EINVAL;
 723         }
 724         mutex_unlock(&css->mutex);
 725         return ret < 0 ? ret : count;
 726 }
 727
 728 static DEVICE_ATTR(cm_enable, 0644, css_cm_enable_show, css_cm_enable_store);
 729
 730 static int __init setup_css(int nr)
 731 {
 732         u32 tod_high;
 733         int ret;
 734         struct channel_subsystem *css;
 735
 736         css = channel_subsystems[nr];
 737         memset(css, 0, sizeof(struct channel_subsystem));
 738         css->pseudo_subchannel =
 739                 kzalloc(sizeof(*css->pseudo_subchannel), GFP_KERNEL);
 740         if (!css->pseudo_subchannel)
 741                 return -ENOMEM;
 742         css->pseudo_subchannel->dev.parent = &css->device;
 743         css->pseudo_subchannel->dev.release = css_subchannel_release;
 744         sprintf(css->pseudo_subchannel->dev.bus_id, "defunct");
 745         ret = cio_create_sch_lock(css->pseudo_subchannel);
 746         if (ret) {
 747                 kfree(css->pseudo_subchannel);
 748                 return ret;
 749         }
 750         mutex_init(&css->mutex);
 751         css->valid = 1;
 752         css->cssid = nr;
 753         sprintf(css->device.bus_id, "css%x", nr);
 754         css->device.release = channel_subsystem_release;
 755         tod_high = (u32) (get_clock() >> 32);
 756         css_generate_pgid(css, tod_high);
 757         return 0;
 758 }
 759
 760 static int css_reboot_event(struct notifier_block *this,
 761                             unsigned long event,
 762                             void *ptr)
 763 {
 764         int ret, i;
 765
 766         ret = NOTIFY_DONE;
 767         for (i = 0; i <= __MAX_CSSID; i++) {
 768                 struct channel_subsystem *css;
 769
 770                 css = channel_subsystems[i];
 771                 mutex_lock(&css->mutex);
 772                 if (css->cm_enabled)
 773                         if (chsc_secm(css, 0))
 774                                 ret = NOTIFY_BAD;
 775                 mutex_unlock(&css->mutex);
 776         }
 777
 778         return ret;
 779 }
 780
 781 static struct notifier_block css_reboot_notifier = {
 782         .notifier_call = css_reboot_event,
 783 };
 784
 785 /*
 786  * Now that the driver core is running, we can setup our channel subsystem.
 787  * The struct subchannel's are created during probing (except for the
 788  * static console subchannel).
 789  */
 790 static int __init
 791 init_channel_subsystem (void)
 792 {
 793         int ret, i;
 794
 795         ret = chsc_determine_css_characteristics();
 796         if (ret == -ENOMEM)
 797                 goto out; /* No need to continue. */
 798         if (ret == 0)
 799                 css_characteristics_avail = 1;
 800
 801         ret = chsc_alloc_sei_area();
 802         if (ret)
 803                 goto out;
 804
 805         ret = slow_subchannel_init();
 806         if (ret)
 807                 goto out;
 808
 809         if ((ret = bus_register(&css_bus_type)))
 810                 goto out;
 811
 812         /* Try to enable MSS. */
 813         ret = chsc_enable_facility(CHSC_SDA_OC_MSS);
 814         switch (ret) {
 815         case 0: /* Success. */
 816                 max_ssid = __MAX_SSID;
 817                 break;
 818         case -ENOMEM:
 819                 goto out_bus;
 820         default:
 821                 max_ssid = 0;
 822         }
 823         /* Setup css structure. */
 824         for (i = 0; i <= __MAX_CSSID; i++) {
 825                 struct channel_subsystem *css;
 826
 827                 css = kmalloc(sizeof(struct channel_subsystem), GFP_KERNEL);
 828                 if (!css) {
 829                         ret = -ENOMEM;
 830                         goto out_unregister;
 831                 }
 832                 channel_subsystems[i] = css;
 833                 ret = setup_css(i);
 834                 if (ret)
 835                         goto out_free;
 836                 ret = device_register(&css->device);
 837                 if (ret)
 838                         goto out_free_all;
 839                 if (css_characteristics_avail &&
 840                     css_chsc_characteristics.secm) {
 841                         ret = device_create_file(&css->device,
 842                                                  &dev_attr_cm_enable);
 843                         if (ret)
 844                                 goto out_device;
 845                 }
 846                 ret = device_register(&css->pseudo_subchannel->dev);
 847                 if (ret)
 848                         goto out_file;
 849         }
 850         ret = register_reboot_notifier(&css_reboot_notifier);
 851         if (ret)
 852                 goto out_pseudo;
 853         css_init_done = 1;
 854
 855         ctl_set_bit(6, 28);
 856
 857         for_each_subchannel(__init_channel_subsystem, NULL);
 858         return 0;
 859 out_pseudo:
 860         device_unregister(&channel_subsystems[i]->pseudo_subchannel->dev);
 861 out_file:
 862         device_remove_file(&channel_subsystems[i]->device,
 863                            &dev_attr_cm_enable);
 864 out_device:
 865         device_unregister(&channel_subsystems[i]->device);
 866 out_free_all:
 867         kfree(channel_subsystems[i]->pseudo_subchannel->lock);
 868         kfree(channel_subsystems[i]->pseudo_subchannel);
 869 out_free:
 870         kfree(channel_subsystems[i]);
 871 out_unregister:
 872         while (i > 0) {
 873                 struct channel_subsystem *css;
 874
 875                 i--;
 876                 css = channel_subsystems[i];
 877                 device_unregister(&css->pseudo_subchannel->dev);
 878                 if (css_characteristics_avail && css_chsc_characteristics.secm)
 879                         device_remove_file(&css->device,
 880                                            &dev_attr_cm_enable);
 881                 device_unregister(&css->device);
 882         }
 883 out_bus:
 884         bus_unregister(&css_bus_type);
 885 out:
 886         chsc_free_sei_area();
 887         kfree(slow_subchannel_set);
 888         printk(KERN_WARNING"cio: failed to initialize css driver (%d)!\n",
 889                ret);
 890         return ret;
 891 }
 892
 893 int sch_is_pseudo_sch(struct subchannel *sch)
 894 {
 895         return sch == to_css(sch->dev.parent)->pseudo_subchannel;
 896 }
 897
 898 /*
 899  * find a driver for a subchannel. They identify by the subchannel
 900  * type with the exception that the console subchannel driver has its own
 901  * subchannel type although the device is an i/o subchannel
 902  */
 903 static int
 904 css_bus_match (struct device *dev, struct device_driver *drv)
 905 {
 906         struct subchannel *sch = to_subchannel(dev);
 907         struct css_driver *driver = to_cssdriver(drv);
 908
 909         if (sch->st == driver->subchannel_type)
 910                 return 1;
 911
 912         return 0;
 913 }
 914
 915 static int css_probe(struct device *dev)
 916 {
 917         struct subchannel *sch;
 918         int ret;
 919
 920         sch = to_subchannel(dev);
 921         sch->driver = to_cssdriver(dev->driver);
 922         ret = sch->driver->probe ? sch->driver->probe(sch) : 0;
 923         if (ret)
 924                 sch->driver = NULL;
 925         return ret;
 926 }
 927
 928 static int css_remove(struct device *dev)
 929 {
 930         struct subchannel *sch;
 931         int ret;
 932
 933         sch = to_subchannel(dev);
 934         ret = sch->driver->remove ? sch->driver->remove(sch) : 0;
 935         sch->driver = NULL;
 936         return ret;
 937 }
 938
 939 static void css_shutdown(struct device *dev)
 940 {
 941         struct subchannel *sch;
 942
 943         sch = to_subchannel(dev);
 944         if (sch->driver && sch->driver->shutdown)
 945                 sch->driver->shutdown(sch);
 946 }
 947
 948 struct bus_type css_bus_type = {
 949         .name     = "css",
 950         .match    = css_bus_match,
 951         .probe    = css_probe,
 952         .remove   = css_remove,
 953         .shutdown = css_shutdown,
 954 };
 955
 956 /**
 957  * css_driver_register - register a css driver
 958  * @cdrv: css driver to register
 959  *
 960  * This is mainly a wrapper around driver_register that sets name
 961  * and bus_type in the embedded struct device_driver correctly.
 962  */
 963 int css_driver_register(struct css_driver *cdrv)
 964 {
 965         cdrv->drv.name = cdrv->name;
 966         cdrv->drv.bus = &css_bus_type;
 967         cdrv->drv.owner = cdrv->owner;
 968         return driver_register(&cdrv->drv);
 969 }
 970 EXPORT_SYMBOL_GPL(css_driver_register);
 971
 972 /**
 973  * css_driver_unregister - unregister a css driver
 974  * @cdrv: css driver to unregister
 975  *
 976  * This is a wrapper around driver_unregister.
 977  */
 978 void css_driver_unregister(struct css_driver *cdrv)
 979 {
 980         driver_unregister(&cdrv->drv);
 981 }
 982 EXPORT_SYMBOL_GPL(css_driver_unregister);
 983
 984 subsys_initcall(init_channel_subsystem);
 985
 986 MODULE_LICENSE("GPL");
 987 EXPORT_SYMBOL(css_bus_type);
 988 EXPORT_SYMBOL_GPL(css_characteristics_avail);