drivers/s390/cio/css.c

   1 /*
   2  *  drivers/s390/cio/css.c
   3  *  driver for channel subsystem
   4  *
   5  *    Copyright IBM Corp. 2002,2008
   6  *    Author(s): Arnd Bergmann (arndb@de.ibm.com)
   7  *               Cornelia Huck (cornelia.huck@de.ibm.com)
   8  */
   9
  10 #define KMSG_COMPONENT "cio"
  11 #define pr_fmt(fmt) KMSG_COMPONENT ": " fmt
  12
  13 #include <linux/module.h>
  14 #include <linux/init.h>
  15 #include <linux/device.h>
  16 #include <linux/slab.h>
  17 #include <linux/errno.h>
  18 #include <linux/list.h>
  19 #include <linux/reboot.h>
  20 #include <asm/isc.h>
  21
  22 #include "../s390mach.h"
  23 #include "css.h"
  24 #include "cio.h"
  25 #include "cio_debug.h"
  26 #include "ioasm.h"
  27 #include "chsc.h"
  28 #include "device.h"
  29 #include "idset.h"
  30 #include "chp.h"
  31
  32 int css_init_done = 0;
  33 static int need_reprobe = 0;
  34 static int max_ssid = 0;
  35
  36 struct channel_subsystem *channel_subsystems[__MAX_CSSID + 1];
  37
  38 int
  39 for_each_subchannel(int(*fn)(struct subchannel_id, void *), void *data)
  40 {
  41         struct subchannel_id schid;
  42         int ret;
  43
  44         init_subchannel_id(&schid);
  45         ret = -ENODEV;
  46         do {
  47                 do {
  48                         ret = fn(schid, data);
  49                         if (ret)
  50                                 break;
  51                 } while (schid.sch_no++ < __MAX_SUBCHANNEL);
  52                 schid.sch_no = 0;
  53         } while (schid.ssid++ < max_ssid);
  54         return ret;
  55 }
  56
  57 struct cb_data {
  58         void *data;
  59         struct idset *set;
  60         int (*fn_known_sch)(struct subchannel *, void *);
  61         int (*fn_unknown_sch)(struct subchannel_id, void *);
  62 };
  63
  64 static int call_fn_known_sch(struct device *dev, void *data)
  65 {
  66         struct subchannel *sch = to_subchannel(dev);
  67         struct cb_data *cb = data;
  68         int rc = 0;
  69
  70         idset_sch_del(cb->set, sch->schid);
  71         if (cb->fn_known_sch)
  72                 rc = cb->fn_known_sch(sch, cb->data);
  73         return rc;
  74 }
  75
  76 static int call_fn_unknown_sch(struct subchannel_id schid, void *data)
  77 {
  78         struct cb_data *cb = data;
  79         int rc = 0;
  80
  81         if (idset_sch_contains(cb->set, schid))
  82                 rc = cb->fn_unknown_sch(schid, cb->data);
  83         return rc;
  84 }
  85
  86 int for_each_subchannel_staged(int (*fn_known)(struct subchannel *, void *),
  87                                int (*fn_unknown)(struct subchannel_id,
  88                                void *), void *data)
  89 {
  90         struct cb_data cb;
  91         int rc;
  92
  93         cb.set = idset_sch_new();
  94         if (!cb.set)
  95                 return -ENOMEM;
  96         idset_fill(cb.set);
  97         cb.data = data;
  98         cb.fn_known_sch = fn_known;
  99         cb.fn_unknown_sch = fn_unknown;
 100         /* Process registered subchannels. */
 101         rc = bus_for_each_dev(&css_bus_type, NULL, &cb, call_fn_known_sch);
 102         if (rc)
 103                 goto out;
 104         /* Process unregistered subchannels. */
 105         if (fn_unknown)
 106                 rc = for_each_subchannel(call_fn_unknown_sch, &cb);
 107 out:
 108         idset_free(cb.set);
 109
 110         return rc;
 111 }
 112
 113 static struct subchannel *
 114 css_alloc_subchannel(struct subchannel_id schid)
 115 {
 116         struct subchannel *sch;
 117         int ret;
 118
 119         sch = kmalloc (sizeof (*sch), GFP_KERNEL | GFP_DMA);
 120         if (sch == NULL)
 121                 return ERR_PTR(-ENOMEM);
 122         ret = cio_validate_subchannel (sch, schid);
 123         if (ret < 0) {
 124                 kfree(sch);
 125                 return ERR_PTR(ret);
 126         }
 127         return sch;
 128 }
 129
 130 static void
 131 css_free_subchannel(struct subchannel *sch)
 132 {
 133         if (sch) {
 134                 /* Reset intparm to zeroes. */
 135                 sch->config.intparm = 0;
 136                 cio_commit_config(sch);
 137                 kfree(sch->lock);
 138                 kfree(sch);
 139         }
 140 }
 141
 142 static void
 143 css_subchannel_release(struct device *dev)
 144 {
 145         struct subchannel *sch;
 146
 147         sch = to_subchannel(dev);
 148         if (!cio_is_console(sch->schid)) {
 149                 kfree(sch->lock);
 150                 kfree(sch);
 151         }
 152 }
 153
 154 static int css_sch_device_register(struct subchannel *sch)
 155 {
 156         int ret;
 157
 158         mutex_lock(&sch->reg_mutex);
 159         ret = device_register(&sch->dev);
 160         mutex_unlock(&sch->reg_mutex);
 161         return ret;
 162 }
 163
 164 /**
 165  * css_sch_device_unregister - unregister a subchannel
 166  * @sch: subchannel to be unregistered
 167  */
 168 void css_sch_device_unregister(struct subchannel *sch)
 169 {
 170         mutex_lock(&sch->reg_mutex);
 171         if (device_is_registered(&sch->dev))
 172                 device_unregister(&sch->dev);
 173         mutex_unlock(&sch->reg_mutex);
 174 }
 175 EXPORT_SYMBOL_GPL(css_sch_device_unregister);
 176
 177 static void ssd_from_pmcw(struct chsc_ssd_info *ssd, struct pmcw *pmcw)
 178 {
 179         int i;
 180         int mask;
 181
 182         memset(ssd, 0, sizeof(struct chsc_ssd_info));
 183         ssd->path_mask = pmcw->pim;
 184         for (i = 0; i < 8; i++) {
 185                 mask = 0x80 >> i;
 186                 if (pmcw->pim & mask) {
 187                         chp_id_init(&ssd->chpid[i]);
 188                         ssd->chpid[i].id = pmcw->chpid[i];
 189                 }
 190         }
 191 }
 192
 193 static void ssd_register_chpids(struct chsc_ssd_info *ssd)
 194 {
 195         int i;
 196         int mask;
 197
 198         for (i = 0; i < 8; i++) {
 199                 mask = 0x80 >> i;
 200                 if (ssd->path_mask & mask)
 201                         if (!chp_is_registered(ssd->chpid[i]))
 202                                 chp_new(ssd->chpid[i]);
 203         }
 204 }
 205
 206 void css_update_ssd_info(struct subchannel *sch)
 207 {
 208         int ret;
 209
 210         if (cio_is_console(sch->schid)) {
 211                 /* Console is initialized too early for functions requiring
 212                  * memory allocation. */
 213                 ssd_from_pmcw(&sch->ssd_info, &sch->schib.pmcw);
 214         } else {
 215                 ret = chsc_get_ssd_info(sch->schid, &sch->ssd_info);
 216                 if (ret)
 217                         ssd_from_pmcw(&sch->ssd_info, &sch->schib.pmcw);
 218                 ssd_register_chpids(&sch->ssd_info);
 219         }
 220 }
 221
 222 static ssize_t type_show(struct device *dev, struct device_attribute *attr,
 223                          char *buf)
 224 {
 225         struct subchannel *sch = to_subchannel(dev);
 226
 227         return sprintf(buf, "%01x\n", sch->st);
 228 }
 229
 230 static DEVICE_ATTR(type, 0444, type_show, NULL);
 231
 232 static ssize_t modalias_show(struct device *dev, struct device_attribute *attr,
 233                              char *buf)
 234 {
 235         struct subchannel *sch = to_subchannel(dev);
 236
 237         return sprintf(buf, "css:t%01X\n", sch->st);
 238 }
 239
 240 static DEVICE_ATTR(modalias, 0444, modalias_show, NULL);
 241
 242 static struct attribute *subch_attrs[] = {
 243         &dev_attr_type.attr,
 244         &dev_attr_modalias.attr,
 245         NULL,
 246 };
 247
 248 static struct attribute_group subch_attr_group = {
 249         .attrs = subch_attrs,
 250 };
 251
 252 static struct attribute_group *default_subch_attr_groups[] = {
 253         &subch_attr_group,
 254         NULL,
 255 };
 256
 257 static int css_register_subchannel(struct subchannel *sch)
 258 {
 259         int ret;
 260
 261         /* Initialize the subchannel structure */
 262         sch->dev.parent = &channel_subsystems[0]->device;
 263         sch->dev.bus = &css_bus_type;
 264         sch->dev.release = &css_subchannel_release;
 265         sch->dev.groups = default_subch_attr_groups;
 266         /*
 267          * We don't want to generate uevents for I/O subchannels that don't
 268          * have a working ccw device behind them since they will be
 269          * unregistered before they can be used anyway, so we delay the add
 270          * uevent until after device recognition was successful.
 271          * Note that we suppress the uevent for all subchannel types;
 272          * the subchannel driver can decide itself when it wants to inform
 273          * userspace of its existence.
 274          */
 275         dev_set_uevent_suppress(&sch->dev, 1);
 276         css_update_ssd_info(sch);
 277         /* make it known to the system */
 278         ret = css_sch_device_register(sch);
 279         if (ret) {
 280                 CIO_MSG_EVENT(0, "Could not register sch 0.%x.%04x: %d\n",
 281                               sch->schid.ssid, sch->schid.sch_no, ret);
 282                 return ret;
 283         }
 284         if (!sch->driver) {
 285                 /*
 286                  * No driver matched. Generate the uevent now so that
 287                  * a fitting driver module may be loaded based on the
 288                  * modalias.
 289                  */
 290                 dev_set_uevent_suppress(&sch->dev, 0);
 291                 kobject_uevent(&sch->dev.kobj, KOBJ_ADD);
 292         }
 293         return ret;
 294 }
 295
 296 int css_probe_device(struct subchannel_id schid)
 297 {
 298         int ret;
 299         struct subchannel *sch;
 300
 301         sch = css_alloc_subchannel(schid);
 302         if (IS_ERR(sch))
 303                 return PTR_ERR(sch);
 304         ret = css_register_subchannel(sch);
 305         if (ret)
 306                 css_free_subchannel(sch);
 307         return ret;
 308 }
 309
 310 static int
 311 check_subchannel(struct device * dev, void * data)
 312 {
 313         struct subchannel *sch;
 314         struct subchannel_id *schid = data;
 315
 316         sch = to_subchannel(dev);
 317         return schid_equal(&sch->schid, schid);
 318 }
 319
 320 struct subchannel *
 321 get_subchannel_by_schid(struct subchannel_id schid)
 322 {
 323         struct device *dev;
 324
 325         dev = bus_find_device(&css_bus_type, NULL,
 326                               &schid, check_subchannel);
 327
 328         return dev ? to_subchannel(dev) : NULL;
 329 }
 330
 331 /**
 332  * css_sch_is_valid() - check if a subchannel is valid
 333  * @schib: subchannel information block for the subchannel
 334  */
 335 int css_sch_is_valid(struct schib *schib)
 336 {
 337         if ((schib->pmcw.st == SUBCHANNEL_TYPE_IO) && !schib->pmcw.dnv)
 338                 return 0;
 339         if ((schib->pmcw.st == SUBCHANNEL_TYPE_MSG) && !schib->pmcw.w)
 340                 return 0;
 341         return 1;
 342 }
 343 EXPORT_SYMBOL_GPL(css_sch_is_valid);
 344
 345 static int css_evaluate_new_subchannel(struct subchannel_id schid, int slow)
 346 {
 347         struct schib schib;
 348
 349         if (!slow) {
 350                 /* Will be done on the slow path. */
 351                 return -EAGAIN;
 352         }
 353         if (stsch_err(schid, &schib) || !css_sch_is_valid(&schib)) {
 354                 /* Unusable - ignore. */
 355                 return 0;
 356         }
 357         CIO_MSG_EVENT(4, "Evaluating schid 0.%x.%04x, event %d, unknown, "
 358                          "slow path.\n", schid.ssid, schid.sch_no, CIO_OPER);
 359
 360         return css_probe_device(schid);
 361 }
 362
 363 static int css_evaluate_known_subchannel(struct subchannel *sch, int slow)
 364 {
 365         int ret = 0;
 366
 367         if (sch->driver) {
 368                 if (sch->driver->sch_event)
 369                         ret = sch->driver->sch_event(sch, slow);
 370                 else
 371                         dev_dbg(&sch->dev,
 372                                 "Got subchannel machine check but "
 373                                 "no sch_event handler provided.\n");
 374         }
 375         return ret;
 376 }
 377
 378 static void css_evaluate_subchannel(struct subchannel_id schid, int slow)
 379 {
 380         struct subchannel *sch;
 381         int ret;
 382
 383         sch = get_subchannel_by_schid(schid);
 384         if (sch) {
 385                 ret = css_evaluate_known_subchannel(sch, slow);
 386                 put_device(&sch->dev);
 387         } else
 388                 ret = css_evaluate_new_subchannel(schid, slow);
 389         if (ret == -EAGAIN)
 390                 css_schedule_eval(schid);
 391 }
 392
 393 static struct idset *slow_subchannel_set;
 394 static spinlock_t slow_subchannel_lock;
 395
 396 static int __init slow_subchannel_init(void)
 397 {
 398         spin_lock_init(&slow_subchannel_lock);
 399         slow_subchannel_set = idset_sch_new();
 400         if (!slow_subchannel_set) {
 401                 CIO_MSG_EVENT(0, "could not allocate slow subchannel set\n");
 402                 return -ENOMEM;
 403         }
 404         return 0;
 405 }
 406
 407 static int slow_eval_known_fn(struct subchannel *sch, void *data)
 408 {
 409         int eval;
 410         int rc;
 411
 412         spin_lock_irq(&slow_subchannel_lock);
 413         eval = idset_sch_contains(slow_subchannel_set, sch->schid);
 414         idset_sch_del(slow_subchannel_set, sch->schid);
 415         spin_unlock_irq(&slow_subchannel_lock);
 416         if (eval) {
 417                 rc = css_evaluate_known_subchannel(sch, 1);
 418                 if (rc == -EAGAIN)
 419                         css_schedule_eval(sch->schid);
 420         }
 421         return 0;
 422 }
 423
 424 static int slow_eval_unknown_fn(struct subchannel_id schid, void *data)
 425 {
 426         int eval;
 427         int rc = 0;
 428
 429         spin_lock_irq(&slow_subchannel_lock);
 430         eval = idset_sch_contains(slow_subchannel_set, schid);
 431         idset_sch_del(slow_subchannel_set, schid);
 432         spin_unlock_irq(&slow_subchannel_lock);
 433         if (eval) {
 434                 rc = css_evaluate_new_subchannel(schid, 1);
 435                 switch (rc) {
 436                 case -EAGAIN:
 437                         css_schedule_eval(schid);
 438                         rc = 0;
 439                         break;
 440                 case -ENXIO:
 441                 case -ENOMEM:
 442                 case -EIO:
 443                         /* These should abort looping */
 444                         break;
 445                 default:
 446                         rc = 0;
 447                 }
 448         }
 449         return rc;
 450 }
 451
 452 static void css_slow_path_func(struct work_struct *unused)
 453 {
 454         CIO_TRACE_EVENT(4, "slowpath");
 455         for_each_subchannel_staged(slow_eval_known_fn, slow_eval_unknown_fn,
 456                                    NULL);
 457 }
 458
 459 static DECLARE_WORK(slow_path_work, css_slow_path_func);
 460 struct workqueue_struct *slow_path_wq;
 461
 462 void css_schedule_eval(struct subchannel_id schid)
 463 {
 464         unsigned long flags;
 465
 466         spin_lock_irqsave(&slow_subchannel_lock, flags);
 467         idset_sch_add(slow_subchannel_set, schid);
 468         queue_work(slow_path_wq, &slow_path_work);
 469         spin_unlock_irqrestore(&slow_subchannel_lock, flags);
 470 }
 471
 472 void css_schedule_eval_all(void)
 473 {
 474         unsigned long flags;
 475
 476         spin_lock_irqsave(&slow_subchannel_lock, flags);
 477         idset_fill(slow_subchannel_set);
 478         queue_work(slow_path_wq, &slow_path_work);
 479         spin_unlock_irqrestore(&slow_subchannel_lock, flags);
 480 }
 481
 482 void css_wait_for_slow_path(void)
 483 {
 484         flush_workqueue(slow_path_wq);
 485 }
 486
 487 /* Reprobe subchannel if unregistered. */
 488 static int reprobe_subchannel(struct subchannel_id schid, void *data)
 489 {
 490         int ret;
 491
 492         CIO_MSG_EVENT(6, "cio: reprobe 0.%x.%04x\n",
 493                       schid.ssid, schid.sch_no);
 494         if (need_reprobe)
 495                 return -EAGAIN;
 496
 497         ret = css_probe_device(schid);
 498         switch (ret) {
 499         case 0:
 500                 break;
 501         case -ENXIO:
 502         case -ENOMEM:
 503         case -EIO:
 504                 /* These should abort looping */
 505                 break;
 506         default:
 507                 ret = 0;
 508         }
 509
 510         return ret;
 511 }
 512
 513 /* Work function used to reprobe all unregistered subchannels. */
 514 static void reprobe_all(struct work_struct *unused)
 515 {
 516         int ret;
 517
 518         CIO_MSG_EVENT(4, "reprobe start\n");
 519
 520         need_reprobe = 0;
 521         /* Make sure initial subchannel scan is done. */
 522         wait_event(ccw_device_init_wq,
 523                    atomic_read(&ccw_device_init_count) == 0);
 524         ret = for_each_subchannel_staged(NULL, reprobe_subchannel, NULL);
 525
 526         CIO_MSG_EVENT(4, "reprobe done (rc=%d, need_reprobe=%d)\n", ret,
 527                       need_reprobe);
 528 }
 529
 530 static DECLARE_WORK(css_reprobe_work, reprobe_all);
 531
 532 /* Schedule reprobing of all unregistered subchannels. */
 533 void css_schedule_reprobe(void)
 534 {
 535         need_reprobe = 1;
 536         queue_work(slow_path_wq, &css_reprobe_work);
 537 }
 538
 539 EXPORT_SYMBOL_GPL(css_schedule_reprobe);
 540
 541 /*
 542  * Called from the machine check handler for subchannel report words.
 543  */
 544 static void css_process_crw(struct crw *crw0, struct crw *crw1, int overflow)
 545 {
 546         struct subchannel_id mchk_schid;
 547
 548         if (overflow) {
 549                 css_schedule_eval_all();
 550                 return;
 551         }
 552         CIO_CRW_EVENT(2, "CRW0 reports slct=%d, oflw=%d, "
 553                       "chn=%d, rsc=%X, anc=%d, erc=%X, rsid=%X\n",
 554                       crw0->slct, crw0->oflw, crw0->chn, crw0->rsc, crw0->anc,
 555                       crw0->erc, crw0->rsid);
 556         if (crw1)
 557                 CIO_CRW_EVENT(2, "CRW1 reports slct=%d, oflw=%d, "
 558                               "chn=%d, rsc=%X, anc=%d, erc=%X, rsid=%X\n",
 559                               crw1->slct, crw1->oflw, crw1->chn, crw1->rsc,
 560                               crw1->anc, crw1->erc, crw1->rsid);
 561         init_subchannel_id(&mchk_schid);
 562         mchk_schid.sch_no = crw0->rsid;
 563         if (crw1)
 564                 mchk_schid.ssid = (crw1->rsid >> 8) & 3;
 565
 566         /*
 567          * Since we are always presented with IPI in the CRW, we have to
 568          * use stsch() to find out if the subchannel in question has come
 569          * or gone.
 570          */
 571         css_evaluate_subchannel(mchk_schid, 0);
 572 }
 573
 574 static int __init
 575 __init_channel_subsystem(struct subchannel_id schid, void *data)
 576 {
 577         struct subchannel *sch;
 578         int ret;
 579
 580         if (cio_is_console(schid))
 581                 sch = cio_get_console_subchannel();
 582         else {
 583                 sch = css_alloc_subchannel(schid);
 584                 if (IS_ERR(sch))
 585                         ret = PTR_ERR(sch);
 586                 else
 587                         ret = 0;
 588                 switch (ret) {
 589                 case 0:
 590                         break;
 591                 case -ENOMEM:
 592                         panic("Out of memory in init_channel_subsystem\n");
 593                 /* -ENXIO: no more subchannels. */
 594                 case -ENXIO:
 595                         return ret;
 596                 /* -EIO: this subchannel set not supported. */
 597                 case -EIO:
 598                         return ret;
 599                 default:
 600                         return 0;
 601                 }
 602         }
 603         /*
 604          * We register ALL valid subchannels in ioinfo, even those
 605          * that have been present before init_channel_subsystem.
 606          * These subchannels can't have been registered yet (kmalloc
 607          * not working) so we do it now. This is true e.g. for the
 608          * console subchannel.
 609          */
 610         css_register_subchannel(sch);
 611         return 0;
 612 }
 613
 614 static void __init
 615 css_generate_pgid(struct channel_subsystem *css, u32 tod_high)
 616 {
 617         if (css_general_characteristics.mcss) {
 618                 css->global_pgid.pgid_high.ext_cssid.version = 0x80;
 619                 css->global_pgid.pgid_high.ext_cssid.cssid = css->cssid;
 620         } else {
 621 #ifdef CONFIG_SMP
 622                 css->global_pgid.pgid_high.cpu_addr = hard_smp_processor_id();
 623 #else
 624                 css->global_pgid.pgid_high.cpu_addr = 0;
 625 #endif
 626         }
 627         css->global_pgid.cpu_id = ((cpuid_t *) __LC_CPUID)->ident;
 628         css->global_pgid.cpu_model = ((cpuid_t *) __LC_CPUID)->machine;
 629         css->global_pgid.tod_high = tod_high;
 630
 631 }
 632
 633 static void
 634 channel_subsystem_release(struct device *dev)
 635 {
 636         struct channel_subsystem *css;
 637
 638         css = to_css(dev);
 639         mutex_destroy(&css->mutex);
 640         if (css->pseudo_subchannel) {
 641                 /* Implies that it has been generated but never registered. */
 642                 css_subchannel_release(&css->pseudo_subchannel->dev);
 643                 css->pseudo_subchannel = NULL;
 644         }
 645         kfree(css);
 646 }
 647
 648 static ssize_t
 649 css_cm_enable_show(struct device *dev, struct device_attribute *attr,
 650                    char *buf)
 651 {
 652         struct channel_subsystem *css = to_css(dev);
 653         int ret;
 654
 655         if (!css)
 656                 return 0;
 657         mutex_lock(&css->mutex);
 658         ret = sprintf(buf, "%x\n", css->cm_enabled);
 659         mutex_unlock(&css->mutex);
 660         return ret;
 661 }
 662
 663 static ssize_t
 664 css_cm_enable_store(struct device *dev, struct device_attribute *attr,
 665                     const char *buf, size_t count)
 666 {
 667         struct channel_subsystem *css = to_css(dev);
 668         int ret;
 669         unsigned long val;
 670
 671         ret = strict_strtoul(buf, 16, &val);
 672         if (ret)
 673                 return ret;
 674         mutex_lock(&css->mutex);
 675         switch (val) {
 676         case 0:
 677                 ret = css->cm_enabled ? chsc_secm(css, 0) : 0;
 678                 break;
 679         case 1:
 680                 ret = css->cm_enabled ? 0 : chsc_secm(css, 1);
 681                 break;
 682         default:
 683                 ret = -EINVAL;
 684         }
 685         mutex_unlock(&css->mutex);
 686         return ret < 0 ? ret : count;
 687 }
 688
 689 static DEVICE_ATTR(cm_enable, 0644, css_cm_enable_show, css_cm_enable_store);
 690
 691 static int __init setup_css(int nr)
 692 {
 693         u32 tod_high;
 694         int ret;
 695         struct channel_subsystem *css;
 696
 697         css = channel_subsystems[nr];
 698         memset(css, 0, sizeof(struct channel_subsystem));
 699         css->pseudo_subchannel =
 700                 kzalloc(sizeof(*css->pseudo_subchannel), GFP_KERNEL);
 701         if (!css->pseudo_subchannel)
 702                 return -ENOMEM;
 703         css->pseudo_subchannel->dev.parent = &css->device;
 704         css->pseudo_subchannel->dev.release = css_subchannel_release;
 705         dev_set_name(&css->pseudo_subchannel->dev, "defunct");
 706         ret = cio_create_sch_lock(css->pseudo_subchannel);
 707         if (ret) {
 708                 kfree(css->pseudo_subchannel);
 709                 return ret;
 710         }
 711         mutex_init(&css->mutex);
 712         css->valid = 1;
 713         css->cssid = nr;
 714         dev_set_name(&css->device, "css%x", nr);
 715         css->device.release = channel_subsystem_release;
 716         tod_high = (u32) (get_clock() >> 32);
 717         css_generate_pgid(css, tod_high);
 718         return 0;
 719 }
 720
 721 static int css_reboot_event(struct notifier_block *this,
 722                             unsigned long event,
 723                             void *ptr)
 724 {
 725         int ret, i;
 726
 727         ret = NOTIFY_DONE;
 728         for (i = 0; i <= __MAX_CSSID; i++) {
 729                 struct channel_subsystem *css;
 730
 731                 css = channel_subsystems[i];
 732                 mutex_lock(&css->mutex);
 733                 if (css->cm_enabled)
 734                         if (chsc_secm(css, 0))
 735                                 ret = NOTIFY_BAD;
 736                 mutex_unlock(&css->mutex);
 737         }
 738
 739         return ret;
 740 }
 741
 742 static struct notifier_block css_reboot_notifier = {
 743         .notifier_call = css_reboot_event,
 744 };
 745
 746 /*
 747  * Now that the driver core is running, we can setup our channel subsystem.
 748  * The struct subchannel's are created during probing (except for the
 749  * static console subchannel).
 750  */
 751 static int __init
 752 init_channel_subsystem (void)
 753 {
 754         int ret, i;
 755
 756         ret = chsc_determine_css_characteristics();
 757         if (ret == -ENOMEM)
 758                 goto out; /* No need to continue. */
 759
 760         ret = chsc_alloc_sei_area();
 761         if (ret)
 762                 goto out;
 763
 764         ret = slow_subchannel_init();
 765         if (ret)
 766                 goto out;
 767
 768         ret = s390_register_crw_handler(CRW_RSC_SCH, css_process_crw);
 769         if (ret)
 770                 goto out;
 771
 772         if ((ret = bus_register(&css_bus_type)))
 773                 goto out;
 774
 775         /* Try to enable MSS. */
 776         ret = chsc_enable_facility(CHSC_SDA_OC_MSS);
 777         switch (ret) {
 778         case 0: /* Success. */
 779                 max_ssid = __MAX_SSID;
 780                 break;
 781         case -ENOMEM:
 782                 goto out_bus;
 783         default:
 784                 max_ssid = 0;
 785         }
 786         /* Setup css structure. */
 787         for (i = 0; i <= __MAX_CSSID; i++) {
 788                 struct channel_subsystem *css;
 789
 790                 css = kmalloc(sizeof(struct channel_subsystem), GFP_KERNEL);
 791                 if (!css) {
 792                         ret = -ENOMEM;
 793                         goto out_unregister;
 794                 }
 795                 channel_subsystems[i] = css;
 796                 ret = setup_css(i);
 797                 if (ret) {
 798                         kfree(channel_subsystems[i]);
 799                         goto out_unregister;
 800                 }
 801                 ret = device_register(&css->device);
 802                 if (ret) {
 803                         put_device(&css->device);
 804                         goto out_unregister;
 805                 }
 806                 if (css_chsc_characteristics.secm) {
 807                         ret = device_create_file(&css->device,
 808                                                  &dev_attr_cm_enable);
 809                         if (ret)
 810                                 goto out_device;
 811                 }
 812                 ret = device_register(&css->pseudo_subchannel->dev);
 813                 if (ret)
 814                         goto out_file;
 815         }
 816         ret = register_reboot_notifier(&css_reboot_notifier);
 817         if (ret)
 818                 goto out_unregister;
 819         css_init_done = 1;
 820
 821         /* Enable default isc for I/O subchannels. */
 822         isc_register(IO_SCH_ISC);
 823
 824         for_each_subchannel(__init_channel_subsystem, NULL);
 825         return 0;
 826 out_file:
 827         if (css_chsc_characteristics.secm)
 828                 device_remove_file(&channel_subsystems[i]->device,
 829                                    &dev_attr_cm_enable);
 830 out_device:
 831         device_unregister(&channel_subsystems[i]->device);
 832 out_unregister:
 833         while (i > 0) {
 834                 struct channel_subsystem *css;
 835
 836                 i--;
 837                 css = channel_subsystems[i];
 838                 device_unregister(&css->pseudo_subchannel->dev);
 839                 css->pseudo_subchannel = NULL;
 840                 if (css_chsc_characteristics.secm)
 841                         device_remove_file(&css->device,
 842                                            &dev_attr_cm_enable);
 843                 device_unregister(&css->device);
 844         }
 845 out_bus:
 846         bus_unregister(&css_bus_type);
 847 out:
 848         s390_unregister_crw_handler(CRW_RSC_CSS);
 849         chsc_free_sei_area();
 850         kfree(slow_subchannel_set);
 851         pr_alert("The CSS device driver initialization failed with "
 852                  "errno=%d\n", ret);
 853         return ret;
 854 }
 855
 856 int sch_is_pseudo_sch(struct subchannel *sch)
 857 {
 858         return sch == to_css(sch->dev.parent)->pseudo_subchannel;
 859 }
 860
 861 static int css_bus_match(struct device *dev, struct device_driver *drv)
 862 {
 863         struct subchannel *sch = to_subchannel(dev);
 864         struct css_driver *driver = to_cssdriver(drv);
 865         struct css_device_id *id;
 866
 867         for (id = driver->subchannel_type; id->match_flags; id++) {
 868                 if (sch->st == id->type)
 869                         return 1;
 870         }
 871
 872         return 0;
 873 }
 874
 875 static int css_probe(struct device *dev)
 876 {
 877         struct subchannel *sch;
 878         int ret;
 879
 880         sch = to_subchannel(dev);
 881         sch->driver = to_cssdriver(dev->driver);
 882         ret = sch->driver->probe ? sch->driver->probe(sch) : 0;
 883         if (ret)
 884                 sch->driver = NULL;
 885         return ret;
 886 }
 887
 888 static int css_remove(struct device *dev)
 889 {
 890         struct subchannel *sch;
 891         int ret;
 892
 893         sch = to_subchannel(dev);
 894         ret = sch->driver->remove ? sch->driver->remove(sch) : 0;
 895         sch->driver = NULL;
 896         return ret;
 897 }
 898
 899 static void css_shutdown(struct device *dev)
 900 {
 901         struct subchannel *sch;
 902
 903         sch = to_subchannel(dev);
 904         if (sch->driver && sch->driver->shutdown)
 905                 sch->driver->shutdown(sch);
 906 }
 907
 908 static int css_uevent(struct device *dev, struct kobj_uevent_env *env)
 909 {
 910         struct subchannel *sch = to_subchannel(dev);
 911         int ret;
 912
 913         ret = add_uevent_var(env, "ST=%01X", sch->st);
 914         if (ret)
 915                 return ret;
 916         ret = add_uevent_var(env, "MODALIAS=css:t%01X", sch->st);
 917         return ret;
 918 }
 919
 920 struct bus_type css_bus_type = {
 921         .name     = "css",
 922         .match    = css_bus_match,
 923         .probe    = css_probe,
 924         .remove   = css_remove,
 925         .shutdown = css_shutdown,
 926         .uevent   = css_uevent,
 927 };
 928
 929 /**
 930  * css_driver_register - register a css driver
 931  * @cdrv: css driver to register
 932  *
 933  * This is mainly a wrapper around driver_register that sets name
 934  * and bus_type in the embedded struct device_driver correctly.
 935  */
 936 int css_driver_register(struct css_driver *cdrv)
 937 {
 938         cdrv->drv.name = cdrv->name;
 939         cdrv->drv.bus = &css_bus_type;
 940         cdrv->drv.owner = cdrv->owner;
 941         return driver_register(&cdrv->drv);
 942 }
 943 EXPORT_SYMBOL_GPL(css_driver_register);
 944
 945 /**
 946  * css_driver_unregister - unregister a css driver
 947  * @cdrv: css driver to unregister
 948  *
 949  * This is a wrapper around driver_unregister.
 950  */
 951 void css_driver_unregister(struct css_driver *cdrv)
 952 {
 953         driver_unregister(&cdrv->drv);
 954 }
 955 EXPORT_SYMBOL_GPL(css_driver_unregister);
 956
 957 subsys_initcall(init_channel_subsystem);
 958
 959 MODULE_LICENSE("GPL");
 960 EXPORT_SYMBOL(css_bus_type);