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   1 /*
   2  * driver for channel subsystem
   3  *
   4  * Copyright IBM Corp. 2002, 2009
   5  *
   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 <linux/suspend.h>
  21 #include <asm/isc.h>
  22 #include <asm/crw.h>
  23
  24 #include "css.h"
  25 #include "cio.h"
  26 #include "cio_debug.h"
  27 #include "ioasm.h"
  28 #include "chsc.h"
  29 #include "device.h"
  30 #include "idset.h"
  31 #include "chp.h"
  32
  33 int css_init_done = 0;
  34 int max_ssid;
  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 static int call_fn_all_sch(struct subchannel_id schid, void *data)
  87 {
  88         struct cb_data *cb = data;
  89         struct subchannel *sch;
  90         int rc = 0;
  91
  92         sch = get_subchannel_by_schid(schid);
  93         if (sch) {
  94                 if (cb->fn_known_sch)
  95                         rc = cb->fn_known_sch(sch, cb->data);
  96                 put_device(&sch->dev);
  97         } else {
  98                 if (cb->fn_unknown_sch)
  99                         rc = cb->fn_unknown_sch(schid, cb->data);
 100         }
 101
 102         return rc;
 103 }
 104
 105 int for_each_subchannel_staged(int (*fn_known)(struct subchannel *, void *),
 106                                int (*fn_unknown)(struct subchannel_id,
 107                                void *), void *data)
 108 {
 109         struct cb_data cb;
 110         int rc;
 111
 112         cb.data = data;
 113         cb.fn_known_sch = fn_known;
 114         cb.fn_unknown_sch = fn_unknown;
 115
 116         cb.set = idset_sch_new();
 117         if (!cb.set)
 118                 /* fall back to brute force scanning in case of oom */
 119                 return for_each_subchannel(call_fn_all_sch, &cb);
 120
 121         idset_fill(cb.set);
 122
 123         /* Process registered subchannels. */
 124         rc = bus_for_each_dev(&css_bus_type, NULL, &cb, call_fn_known_sch);
 125         if (rc)
 126                 goto out;
 127         /* Process unregistered subchannels. */
 128         if (fn_unknown)
 129                 rc = for_each_subchannel(call_fn_unknown_sch, &cb);
 130 out:
 131         idset_free(cb.set);
 132
 133         return rc;
 134 }
 135
 136 static struct subchannel *
 137 css_alloc_subchannel(struct subchannel_id schid)
 138 {
 139         struct subchannel *sch;
 140         int ret;
 141
 142         sch = kmalloc (sizeof (*sch), GFP_KERNEL | GFP_DMA);
 143         if (sch == NULL)
 144                 return ERR_PTR(-ENOMEM);
 145         ret = cio_validate_subchannel (sch, schid);
 146         if (ret < 0) {
 147                 kfree(sch);
 148                 return ERR_PTR(ret);
 149         }
 150         return sch;
 151 }
 152
 153 static void
 154 css_subchannel_release(struct device *dev)
 155 {
 156         struct subchannel *sch;
 157
 158         sch = to_subchannel(dev);
 159         if (!cio_is_console(sch->schid)) {
 160                 /* Reset intparm to zeroes. */
 161                 sch->config.intparm = 0;
 162                 cio_commit_config(sch);
 163                 kfree(sch->lock);
 164                 kfree(sch);
 165         }
 166 }
 167
 168 static int css_sch_device_register(struct subchannel *sch)
 169 {
 170         int ret;
 171
 172         mutex_lock(&sch->reg_mutex);
 173         dev_set_name(&sch->dev, "0.%x.%04x", sch->schid.ssid,
 174                      sch->schid.sch_no);
 175         ret = device_register(&sch->dev);
 176         mutex_unlock(&sch->reg_mutex);
 177         return ret;
 178 }
 179
 180 /**
 181  * css_sch_device_unregister - unregister a subchannel
 182  * @sch: subchannel to be unregistered
 183  */
 184 void css_sch_device_unregister(struct subchannel *sch)
 185 {
 186         mutex_lock(&sch->reg_mutex);
 187         if (device_is_registered(&sch->dev))
 188                 device_unregister(&sch->dev);
 189         mutex_unlock(&sch->reg_mutex);
 190 }
 191 EXPORT_SYMBOL_GPL(css_sch_device_unregister);
 192
 193 static void ssd_from_pmcw(struct chsc_ssd_info *ssd, struct pmcw *pmcw)
 194 {
 195         int i;
 196         int mask;
 197
 198         memset(ssd, 0, sizeof(struct chsc_ssd_info));
 199         ssd->path_mask = pmcw->pim;
 200         for (i = 0; i < 8; i++) {
 201                 mask = 0x80 >> i;
 202                 if (pmcw->pim & mask) {
 203                         chp_id_init(&ssd->chpid[i]);
 204                         ssd->chpid[i].id = pmcw->chpid[i];
 205                 }
 206         }
 207 }
 208
 209 static void ssd_register_chpids(struct chsc_ssd_info *ssd)
 210 {
 211         int i;
 212         int mask;
 213
 214         for (i = 0; i < 8; i++) {
 215                 mask = 0x80 >> i;
 216                 if (ssd->path_mask & mask)
 217                         if (!chp_is_registered(ssd->chpid[i]))
 218                                 chp_new(ssd->chpid[i]);
 219         }
 220 }
 221
 222 void css_update_ssd_info(struct subchannel *sch)
 223 {
 224         int ret;
 225
 226         if (cio_is_console(sch->schid)) {
 227                 /* Console is initialized too early for functions requiring
 228                  * memory allocation. */
 229                 ssd_from_pmcw(&sch->ssd_info, &sch->schib.pmcw);
 230         } else {
 231                 ret = chsc_get_ssd_info(sch->schid, &sch->ssd_info);
 232                 if (ret)
 233                         ssd_from_pmcw(&sch->ssd_info, &sch->schib.pmcw);
 234                 ssd_register_chpids(&sch->ssd_info);
 235         }
 236 }
 237
 238 static ssize_t type_show(struct device *dev, struct device_attribute *attr,
 239                          char *buf)
 240 {
 241         struct subchannel *sch = to_subchannel(dev);
 242
 243         return sprintf(buf, "%01x\n", sch->st);
 244 }
 245
 246 static DEVICE_ATTR(type, 0444, type_show, NULL);
 247
 248 static ssize_t modalias_show(struct device *dev, struct device_attribute *attr,
 249                              char *buf)
 250 {
 251         struct subchannel *sch = to_subchannel(dev);
 252
 253         return sprintf(buf, "css:t%01X\n", sch->st);
 254 }
 255
 256 static DEVICE_ATTR(modalias, 0444, modalias_show, NULL);
 257
 258 static struct attribute *subch_attrs[] = {
 259         &dev_attr_type.attr,
 260         &dev_attr_modalias.attr,
 261         NULL,
 262 };
 263
 264 static struct attribute_group subch_attr_group = {
 265         .attrs = subch_attrs,
 266 };
 267
 268 static const struct attribute_group *default_subch_attr_groups[] = {
 269         &subch_attr_group,
 270         NULL,
 271 };
 272
 273 static int css_register_subchannel(struct subchannel *sch)
 274 {
 275         int ret;
 276
 277         /* Initialize the subchannel structure */
 278         sch->dev.parent = &channel_subsystems[0]->device;
 279         sch->dev.bus = &css_bus_type;
 280         sch->dev.release = &css_subchannel_release;
 281         sch->dev.groups = default_subch_attr_groups;
 282         /*
 283          * We don't want to generate uevents for I/O subchannels that don't
 284          * have a working ccw device behind them since they will be
 285          * unregistered before they can be used anyway, so we delay the add
 286          * uevent until after device recognition was successful.
 287          * Note that we suppress the uevent for all subchannel types;
 288          * the subchannel driver can decide itself when it wants to inform
 289          * userspace of its existence.
 290          */
 291         dev_set_uevent_suppress(&sch->dev, 1);
 292         css_update_ssd_info(sch);
 293         /* make it known to the system */
 294         ret = css_sch_device_register(sch);
 295         if (ret) {
 296                 CIO_MSG_EVENT(0, "Could not register sch 0.%x.%04x: %d\n",
 297                               sch->schid.ssid, sch->schid.sch_no, ret);
 298                 return ret;
 299         }
 300         if (!sch->driver) {
 301                 /*
 302                  * No driver matched. Generate the uevent now so that
 303                  * a fitting driver module may be loaded based on the
 304                  * modalias.
 305                  */
 306                 dev_set_uevent_suppress(&sch->dev, 0);
 307                 kobject_uevent(&sch->dev.kobj, KOBJ_ADD);
 308         }
 309         return ret;
 310 }
 311
 312 int css_probe_device(struct subchannel_id schid)
 313 {
 314         int ret;
 315         struct subchannel *sch;
 316
 317         if (cio_is_console(schid))
 318                 sch = cio_get_console_subchannel();
 319         else {
 320                 sch = css_alloc_subchannel(schid);
 321                 if (IS_ERR(sch))
 322                         return PTR_ERR(sch);
 323         }
 324         ret = css_register_subchannel(sch);
 325         if (ret) {
 326                 if (!cio_is_console(schid))
 327                         put_device(&sch->dev);
 328         }
 329         return ret;
 330 }
 331
 332 static int
 333 check_subchannel(struct device * dev, void * data)
 334 {
 335         struct subchannel *sch;
 336         struct subchannel_id *schid = data;
 337
 338         sch = to_subchannel(dev);
 339         return schid_equal(&sch->schid, schid);
 340 }
 341
 342 struct subchannel *
 343 get_subchannel_by_schid(struct subchannel_id schid)
 344 {
 345         struct device *dev;
 346
 347         dev = bus_find_device(&css_bus_type, NULL,
 348                               &schid, check_subchannel);
 349
 350         return dev ? to_subchannel(dev) : NULL;
 351 }
 352
 353 /**
 354  * css_sch_is_valid() - check if a subchannel is valid
 355  * @schib: subchannel information block for the subchannel
 356  */
 357 int css_sch_is_valid(struct schib *schib)
 358 {
 359         if ((schib->pmcw.st == SUBCHANNEL_TYPE_IO) && !schib->pmcw.dnv)
 360                 return 0;
 361         if ((schib->pmcw.st == SUBCHANNEL_TYPE_MSG) && !schib->pmcw.w)
 362                 return 0;
 363         return 1;
 364 }
 365 EXPORT_SYMBOL_GPL(css_sch_is_valid);
 366
 367 static int css_evaluate_new_subchannel(struct subchannel_id schid, int slow)
 368 {
 369         struct schib schib;
 370
 371         if (!slow) {
 372                 /* Will be done on the slow path. */
 373                 return -EAGAIN;
 374         }
 375         if (stsch_err(schid, &schib) || !css_sch_is_valid(&schib)) {
 376                 /* Unusable - ignore. */
 377                 return 0;
 378         }
 379         CIO_MSG_EVENT(4, "event: sch 0.%x.%04x, new\n", schid.ssid,
 380                       schid.sch_no);
 381
 382         return css_probe_device(schid);
 383 }
 384
 385 static int css_evaluate_known_subchannel(struct subchannel *sch, int slow)
 386 {
 387         int ret = 0;
 388
 389         if (sch->driver) {
 390                 if (sch->driver->sch_event)
 391                         ret = sch->driver->sch_event(sch, slow);
 392                 else
 393                         dev_dbg(&sch->dev,
 394                                 "Got subchannel machine check but "
 395                                 "no sch_event handler provided.\n");
 396         }
 397         if (ret != 0 && ret != -EAGAIN) {
 398                 CIO_MSG_EVENT(2, "eval: sch 0.%x.%04x, rc=%d\n",
 399                               sch->schid.ssid, sch->schid.sch_no, ret);
 400         }
 401         return ret;
 402 }
 403
 404 static void css_evaluate_subchannel(struct subchannel_id schid, int slow)
 405 {
 406         struct subchannel *sch;
 407         int ret;
 408
 409         sch = get_subchannel_by_schid(schid);
 410         if (sch) {
 411                 ret = css_evaluate_known_subchannel(sch, slow);
 412                 put_device(&sch->dev);
 413         } else
 414                 ret = css_evaluate_new_subchannel(schid, slow);
 415         if (ret == -EAGAIN)
 416                 css_schedule_eval(schid);
 417 }
 418
 419 static struct idset *slow_subchannel_set;
 420 static spinlock_t slow_subchannel_lock;
 421 static wait_queue_head_t css_eval_wq;
 422 static atomic_t css_eval_scheduled;
 423
 424 static int __init slow_subchannel_init(void)
 425 {
 426         spin_lock_init(&slow_subchannel_lock);
 427         atomic_set(&css_eval_scheduled, 0);
 428         init_waitqueue_head(&css_eval_wq);
 429         slow_subchannel_set = idset_sch_new();
 430         if (!slow_subchannel_set) {
 431                 CIO_MSG_EVENT(0, "could not allocate slow subchannel set\n");
 432                 return -ENOMEM;
 433         }
 434         return 0;
 435 }
 436
 437 static int slow_eval_known_fn(struct subchannel *sch, void *data)
 438 {
 439         int eval;
 440         int rc;
 441
 442         spin_lock_irq(&slow_subchannel_lock);
 443         eval = idset_sch_contains(slow_subchannel_set, sch->schid);
 444         idset_sch_del(slow_subchannel_set, sch->schid);
 445         spin_unlock_irq(&slow_subchannel_lock);
 446         if (eval) {
 447                 rc = css_evaluate_known_subchannel(sch, 1);
 448                 if (rc == -EAGAIN)
 449                         css_schedule_eval(sch->schid);
 450         }
 451         return 0;
 452 }
 453
 454 static int slow_eval_unknown_fn(struct subchannel_id schid, void *data)
 455 {
 456         int eval;
 457         int rc = 0;
 458
 459         spin_lock_irq(&slow_subchannel_lock);
 460         eval = idset_sch_contains(slow_subchannel_set, schid);
 461         idset_sch_del(slow_subchannel_set, schid);
 462         spin_unlock_irq(&slow_subchannel_lock);
 463         if (eval) {
 464                 rc = css_evaluate_new_subchannel(schid, 1);
 465                 switch (rc) {
 466                 case -EAGAIN:
 467                         css_schedule_eval(schid);
 468                         rc = 0;
 469                         break;
 470                 case -ENXIO:
 471                 case -ENOMEM:
 472                 case -EIO:
 473                         /* These should abort looping */
 474                         break;
 475                 default:
 476                         rc = 0;
 477                 }
 478         }
 479         return rc;
 480 }
 481
 482 static void css_slow_path_func(struct work_struct *unused)
 483 {
 484         unsigned long flags;
 485
 486         CIO_TRACE_EVENT(4, "slowpath");
 487         for_each_subchannel_staged(slow_eval_known_fn, slow_eval_unknown_fn,
 488                                    NULL);
 489         spin_lock_irqsave(&slow_subchannel_lock, flags);
 490         if (idset_is_empty(slow_subchannel_set)) {
 491                 atomic_set(&css_eval_scheduled, 0);
 492                 wake_up(&css_eval_wq);
 493         }
 494         spin_unlock_irqrestore(&slow_subchannel_lock, flags);
 495 }
 496
 497 static DECLARE_WORK(slow_path_work, css_slow_path_func);
 498 struct workqueue_struct *slow_path_wq;
 499
 500 void css_schedule_eval(struct subchannel_id schid)
 501 {
 502         unsigned long flags;
 503
 504         spin_lock_irqsave(&slow_subchannel_lock, flags);
 505         idset_sch_add(slow_subchannel_set, schid);
 506         atomic_set(&css_eval_scheduled, 1);
 507         queue_work(slow_path_wq, &slow_path_work);
 508         spin_unlock_irqrestore(&slow_subchannel_lock, flags);
 509 }
 510
 511 void css_schedule_eval_all(void)
 512 {
 513         unsigned long flags;
 514
 515         spin_lock_irqsave(&slow_subchannel_lock, flags);
 516         idset_fill(slow_subchannel_set);
 517         atomic_set(&css_eval_scheduled, 1);
 518         queue_work(slow_path_wq, &slow_path_work);
 519         spin_unlock_irqrestore(&slow_subchannel_lock, flags);
 520 }
 521
 522 static int __unset_registered(struct device *dev, void *data)
 523 {
 524         struct idset *set = data;
 525         struct subchannel *sch = to_subchannel(dev);
 526
 527         idset_sch_del(set, sch->schid);
 528         return 0;
 529 }
 530
 531 void css_schedule_eval_all_unreg(void)
 532 {
 533         unsigned long flags;
 534         struct idset *unreg_set;
 535
 536         /* Find unregistered subchannels. */
 537         unreg_set = idset_sch_new();
 538         if (!unreg_set) {
 539                 /* Fallback. */
 540                 css_schedule_eval_all();
 541                 return;
 542         }
 543         idset_fill(unreg_set);
 544         bus_for_each_dev(&css_bus_type, NULL, unreg_set, __unset_registered);
 545         /* Apply to slow_subchannel_set. */
 546         spin_lock_irqsave(&slow_subchannel_lock, flags);
 547         idset_add_set(slow_subchannel_set, unreg_set);
 548         atomic_set(&css_eval_scheduled, 1);
 549         queue_work(slow_path_wq, &slow_path_work);
 550         spin_unlock_irqrestore(&slow_subchannel_lock, flags);
 551         idset_free(unreg_set);
 552 }
 553
 554 void css_wait_for_slow_path(void)
 555 {
 556         flush_workqueue(slow_path_wq);
 557 }
 558
 559 /* Schedule reprobing of all unregistered subchannels. */
 560 void css_schedule_reprobe(void)
 561 {
 562         css_schedule_eval_all_unreg();
 563 }
 564 EXPORT_SYMBOL_GPL(css_schedule_reprobe);
 565
 566 /*
 567  * Called from the machine check handler for subchannel report words.
 568  */
 569 static void css_process_crw(struct crw *crw0, struct crw *crw1, int overflow)
 570 {
 571         struct subchannel_id mchk_schid;
 572
 573         if (overflow) {
 574                 css_schedule_eval_all();
 575                 return;
 576         }
 577         CIO_CRW_EVENT(2, "CRW0 reports slct=%d, oflw=%d, "
 578                       "chn=%d, rsc=%X, anc=%d, erc=%X, rsid=%X\n",
 579                       crw0->slct, crw0->oflw, crw0->chn, crw0->rsc, crw0->anc,
 580                       crw0->erc, crw0->rsid);
 581         if (crw1)
 582                 CIO_CRW_EVENT(2, "CRW1 reports slct=%d, oflw=%d, "
 583                               "chn=%d, rsc=%X, anc=%d, erc=%X, rsid=%X\n",
 584                               crw1->slct, crw1->oflw, crw1->chn, crw1->rsc,
 585                               crw1->anc, crw1->erc, crw1->rsid);
 586         init_subchannel_id(&mchk_schid);
 587         mchk_schid.sch_no = crw0->rsid;
 588         if (crw1)
 589                 mchk_schid.ssid = (crw1->rsid >> 8) & 3;
 590
 591         /*
 592          * Since we are always presented with IPI in the CRW, we have to
 593          * use stsch() to find out if the subchannel in question has come
 594          * or gone.
 595          */
 596         css_evaluate_subchannel(mchk_schid, 0);
 597 }
 598
 599 static void __init
 600 css_generate_pgid(struct channel_subsystem *css, u32 tod_high)
 601 {
 602         if (css_general_characteristics.mcss) {
 603                 css->global_pgid.pgid_high.ext_cssid.version = 0x80;
 604                 css->global_pgid.pgid_high.ext_cssid.cssid = css->cssid;
 605         } else {
 606 #ifdef CONFIG_SMP
 607                 css->global_pgid.pgid_high.cpu_addr = stap();
 608 #else
 609                 css->global_pgid.pgid_high.cpu_addr = 0;
 610 #endif
 611         }
 612         css->global_pgid.cpu_id = S390_lowcore.cpu_id.ident;
 613         css->global_pgid.cpu_model = S390_lowcore.cpu_id.machine;
 614         css->global_pgid.tod_high = tod_high;
 615
 616 }
 617
 618 static void
 619 channel_subsystem_release(struct device *dev)
 620 {
 621         struct channel_subsystem *css;
 622
 623         css = to_css(dev);
 624         mutex_destroy(&css->mutex);
 625         if (css->pseudo_subchannel) {
 626                 /* Implies that it has been generated but never registered. */
 627                 css_subchannel_release(&css->pseudo_subchannel->dev);
 628                 css->pseudo_subchannel = NULL;
 629         }
 630         kfree(css);
 631 }
 632
 633 static ssize_t
 634 css_cm_enable_show(struct device *dev, struct device_attribute *attr,
 635                    char *buf)
 636 {
 637         struct channel_subsystem *css = to_css(dev);
 638         int ret;
 639
 640         if (!css)
 641                 return 0;
 642         mutex_lock(&css->mutex);
 643         ret = sprintf(buf, "%x\n", css->cm_enabled);
 644         mutex_unlock(&css->mutex);
 645         return ret;
 646 }
 647
 648 static ssize_t
 649 css_cm_enable_store(struct device *dev, struct device_attribute *attr,
 650                     const char *buf, size_t count)
 651 {
 652         struct channel_subsystem *css = to_css(dev);
 653         int ret;
 654         unsigned long val;
 655
 656         ret = strict_strtoul(buf, 16, &val);
 657         if (ret)
 658                 return ret;
 659         mutex_lock(&css->mutex);
 660         switch (val) {
 661         case 0:
 662                 ret = css->cm_enabled ? chsc_secm(css, 0) : 0;
 663                 break;
 664         case 1:
 665                 ret = css->cm_enabled ? 0 : chsc_secm(css, 1);
 666                 break;
 667         default:
 668                 ret = -EINVAL;
 669         }
 670         mutex_unlock(&css->mutex);
 671         return ret < 0 ? ret : count;
 672 }
 673
 674 static DEVICE_ATTR(cm_enable, 0644, css_cm_enable_show, css_cm_enable_store);
 675
 676 static int __init setup_css(int nr)
 677 {
 678         u32 tod_high;
 679         int ret;
 680         struct channel_subsystem *css;
 681
 682         css = channel_subsystems[nr];
 683         memset(css, 0, sizeof(struct channel_subsystem));
 684         css->pseudo_subchannel =
 685                 kzalloc(sizeof(*css->pseudo_subchannel), GFP_KERNEL);
 686         if (!css->pseudo_subchannel)
 687                 return -ENOMEM;
 688         css->pseudo_subchannel->dev.parent = &css->device;
 689         css->pseudo_subchannel->dev.release = css_subchannel_release;
 690         dev_set_name(&css->pseudo_subchannel->dev, "defunct");
 691         mutex_init(&css->pseudo_subchannel->reg_mutex);
 692         ret = cio_create_sch_lock(css->pseudo_subchannel);
 693         if (ret) {
 694                 kfree(css->pseudo_subchannel);
 695                 return ret;
 696         }
 697         mutex_init(&css->mutex);
 698         css->valid = 1;
 699         css->cssid = nr;
 700         dev_set_name(&css->device, "css%x", nr);
 701         css->device.release = channel_subsystem_release;
 702         tod_high = (u32) (get_clock() >> 32);
 703         css_generate_pgid(css, tod_high);
 704         return 0;
 705 }
 706
 707 static int css_reboot_event(struct notifier_block *this,
 708                             unsigned long event,
 709                             void *ptr)
 710 {
 711         int ret, i;
 712
 713         ret = NOTIFY_DONE;
 714         for (i = 0; i <= __MAX_CSSID; i++) {
 715                 struct channel_subsystem *css;
 716
 717                 css = channel_subsystems[i];
 718                 mutex_lock(&css->mutex);
 719                 if (css->cm_enabled)
 720                         if (chsc_secm(css, 0))
 721                                 ret = NOTIFY_BAD;
 722                 mutex_unlock(&css->mutex);
 723         }
 724
 725         return ret;
 726 }
 727
 728 static struct notifier_block css_reboot_notifier = {
 729         .notifier_call = css_reboot_event,
 730 };
 731
 732 /*
 733  * Since the css devices are neither on a bus nor have a class
 734  * nor have a special device type, we cannot stop/restart channel
 735  * path measurements via the normal suspend/resume callbacks, but have
 736  * to use notifiers.
 737  */
 738 static int css_power_event(struct notifier_block *this, unsigned long event,
 739                            void *ptr)
 740 {
 741         void *secm_area;
 742         int ret, i;
 743
 744         switch (event) {
 745         case PM_HIBERNATION_PREPARE:
 746         case PM_SUSPEND_PREPARE:
 747                 ret = NOTIFY_DONE;
 748                 for (i = 0; i <= __MAX_CSSID; i++) {
 749                         struct channel_subsystem *css;
 750
 751                         css = channel_subsystems[i];
 752                         mutex_lock(&css->mutex);
 753                         if (!css->cm_enabled) {
 754                                 mutex_unlock(&css->mutex);
 755                                 continue;
 756                         }
 757                         secm_area = (void *)get_zeroed_page(GFP_KERNEL |
 758                                                             GFP_DMA);
 759                         if (secm_area) {
 760                                 if (__chsc_do_secm(css, 0, secm_area))
 761                                         ret = NOTIFY_BAD;
 762                                 free_page((unsigned long)secm_area);
 763                         } else
 764                                 ret = NOTIFY_BAD;
 765
 766                         mutex_unlock(&css->mutex);
 767                 }
 768                 break;
 769         case PM_POST_HIBERNATION:
 770         case PM_POST_SUSPEND:
 771                 ret = NOTIFY_DONE;
 772                 for (i = 0; i <= __MAX_CSSID; i++) {
 773                         struct channel_subsystem *css;
 774
 775                         css = channel_subsystems[i];
 776                         mutex_lock(&css->mutex);
 777                         if (!css->cm_enabled) {
 778                                 mutex_unlock(&css->mutex);
 779                                 continue;
 780                         }
 781                         secm_area = (void *)get_zeroed_page(GFP_KERNEL |
 782                                                             GFP_DMA);
 783                         if (secm_area) {
 784                                 if (__chsc_do_secm(css, 1, secm_area))
 785                                         ret = NOTIFY_BAD;
 786                                 free_page((unsigned long)secm_area);
 787                         } else
 788                                 ret = NOTIFY_BAD;
 789
 790                         mutex_unlock(&css->mutex);
 791                 }
 792                 /* search for subchannels, which appeared during hibernation */
 793                 css_schedule_reprobe();
 794                 break;
 795         default:
 796                 ret = NOTIFY_DONE;
 797         }
 798         return ret;
 799
 800 }
 801 static struct notifier_block css_power_notifier = {
 802         .notifier_call = css_power_event,
 803 };
 804
 805 /*
 806  * Now that the driver core is running, we can setup our channel subsystem.
 807  * The struct subchannel's are created during probing (except for the
 808  * static console subchannel).
 809  */
 810 static int __init css_bus_init(void)
 811 {
 812         int ret, i;
 813
 814         ret = chsc_determine_css_characteristics();
 815         if (ret == -ENOMEM)
 816                 goto out;
 817
 818         ret = chsc_alloc_sei_area();
 819         if (ret)
 820                 goto out;
 821
 822         /* Try to enable MSS. */
 823         ret = chsc_enable_facility(CHSC_SDA_OC_MSS);
 824         switch (ret) {
 825         case 0: /* Success. */
 826                 max_ssid = __MAX_SSID;
 827                 break;
 828         case -ENOMEM:
 829                 goto out;
 830         default:
 831                 max_ssid = 0;
 832         }
 833
 834         ret = slow_subchannel_init();
 835         if (ret)
 836                 goto out;
 837
 838         ret = crw_register_handler(CRW_RSC_SCH, css_process_crw);
 839         if (ret)
 840                 goto out;
 841
 842         if ((ret = bus_register(&css_bus_type)))
 843                 goto out;
 844
 845         /* Setup css structure. */
 846         for (i = 0; i <= __MAX_CSSID; i++) {
 847                 struct channel_subsystem *css;
 848
 849                 css = kmalloc(sizeof(struct channel_subsystem), GFP_KERNEL);
 850                 if (!css) {
 851                         ret = -ENOMEM;
 852                         goto out_unregister;
 853                 }
 854                 channel_subsystems[i] = css;
 855                 ret = setup_css(i);
 856                 if (ret) {
 857                         kfree(channel_subsystems[i]);
 858                         goto out_unregister;
 859                 }
 860                 ret = device_register(&css->device);
 861                 if (ret) {
 862                         put_device(&css->device);
 863                         goto out_unregister;
 864                 }
 865                 if (css_chsc_characteristics.secm) {
 866                         ret = device_create_file(&css->device,
 867                                                  &dev_attr_cm_enable);
 868                         if (ret)
 869                                 goto out_device;
 870                 }
 871                 ret = device_register(&css->pseudo_subchannel->dev);
 872                 if (ret) {
 873                         put_device(&css->pseudo_subchannel->dev);
 874                         goto out_file;
 875                 }
 876         }
 877         ret = register_reboot_notifier(&css_reboot_notifier);
 878         if (ret)
 879                 goto out_unregister;
 880         ret = register_pm_notifier(&css_power_notifier);
 881         if (ret) {
 882                 unregister_reboot_notifier(&css_reboot_notifier);
 883                 goto out_unregister;
 884         }
 885         css_init_done = 1;
 886
 887         /* Enable default isc for I/O subchannels. */
 888         isc_register(IO_SCH_ISC);
 889
 890         return 0;
 891 out_file:
 892         if (css_chsc_characteristics.secm)
 893                 device_remove_file(&channel_subsystems[i]->device,
 894                                    &dev_attr_cm_enable);
 895 out_device:
 896         device_unregister(&channel_subsystems[i]->device);
 897 out_unregister:
 898         while (i > 0) {
 899                 struct channel_subsystem *css;
 900
 901                 i--;
 902                 css = channel_subsystems[i];
 903                 device_unregister(&css->pseudo_subchannel->dev);
 904                 css->pseudo_subchannel = NULL;
 905                 if (css_chsc_characteristics.secm)
 906                         device_remove_file(&css->device,
 907                                            &dev_attr_cm_enable);
 908                 device_unregister(&css->device);
 909         }
 910         bus_unregister(&css_bus_type);
 911 out:
 912         crw_unregister_handler(CRW_RSC_CSS);
 913         chsc_free_sei_area();
 914         idset_free(slow_subchannel_set);
 915         pr_alert("The CSS device driver initialization failed with "
 916                  "errno=%d\n", ret);
 917         return ret;
 918 }
 919
 920 static void __init css_bus_cleanup(void)
 921 {
 922         struct channel_subsystem *css;
 923         int i;
 924
 925         for (i = 0; i <= __MAX_CSSID; i++) {
 926                 css = channel_subsystems[i];
 927                 device_unregister(&css->pseudo_subchannel->dev);
 928                 css->pseudo_subchannel = NULL;
 929                 if (css_chsc_characteristics.secm)
 930                         device_remove_file(&css->device, &dev_attr_cm_enable);
 931                 device_unregister(&css->device);
 932         }
 933         bus_unregister(&css_bus_type);
 934         crw_unregister_handler(CRW_RSC_CSS);
 935         chsc_free_sei_area();
 936         idset_free(slow_subchannel_set);
 937         isc_unregister(IO_SCH_ISC);
 938 }
 939
 940 static int __init channel_subsystem_init(void)
 941 {
 942         int ret;
 943
 944         ret = css_bus_init();
 945         if (ret)
 946                 return ret;
 947
 948         ret = io_subchannel_init();
 949         if (ret)
 950                 css_bus_cleanup();
 951
 952         return ret;
 953 }
 954 subsys_initcall(channel_subsystem_init);
 955
 956 static int css_settle(struct device_driver *drv, void *unused)
 957 {
 958         struct css_driver *cssdrv = to_cssdriver(drv);
 959
 960         if (cssdrv->settle)
 961                 cssdrv->settle();
 962         return 0;
 963 }
 964
 965 /*
 966  * Wait for the initialization of devices to finish, to make sure we are
 967  * done with our setup if the search for the root device starts.
 968  */
 969 static int __init channel_subsystem_init_sync(void)
 970 {
 971         /* Start initial subchannel evaluation. */
 972         css_schedule_eval_all();
 973         /* Wait for the evaluation of subchannels to finish. */
 974         wait_event(css_eval_wq, atomic_read(&css_eval_scheduled) == 0);
 975         /* Wait for the subchannel type specific initialization to finish */
 976         return bus_for_each_drv(&css_bus_type, NULL, NULL, css_settle);
 977 }
 978 subsys_initcall_sync(channel_subsystem_init_sync);
 979
 980 int sch_is_pseudo_sch(struct subchannel *sch)
 981 {
 982         return sch == to_css(sch->dev.parent)->pseudo_subchannel;
 983 }
 984
 985 static int css_bus_match(struct device *dev, struct device_driver *drv)
 986 {
 987         struct subchannel *sch = to_subchannel(dev);
 988         struct css_driver *driver = to_cssdriver(drv);
 989         struct css_device_id *id;
 990
 991         for (id = driver->subchannel_type; id->match_flags; id++) {
 992                 if (sch->st == id->type)
 993                         return 1;
 994         }
 995
 996         return 0;
 997 }
 998
 999 static int css_probe(struct device *dev)
1000 {
1001         struct subchannel *sch;
1002         int ret;
1003
1004         sch = to_subchannel(dev);
1005         sch->driver = to_cssdriver(dev->driver);
1006         ret = sch->driver->probe ? sch->driver->probe(sch) : 0;
1007         if (ret)
1008                 sch->driver = NULL;
1009         return ret;
1010 }
1011
1012 static int css_remove(struct device *dev)
1013 {
1014         struct subchannel *sch;
1015         int ret;
1016
1017         sch = to_subchannel(dev);
1018         ret = sch->driver->remove ? sch->driver->remove(sch) : 0;
1019         sch->driver = NULL;
1020         return ret;
1021 }
1022
1023 static void css_shutdown(struct device *dev)
1024 {
1025         struct subchannel *sch;
1026
1027         sch = to_subchannel(dev);
1028         if (sch->driver && sch->driver->shutdown)
1029                 sch->driver->shutdown(sch);
1030 }
1031
1032 static int css_uevent(struct device *dev, struct kobj_uevent_env *env)
1033 {
1034         struct subchannel *sch = to_subchannel(dev);
1035         int ret;
1036
1037         ret = add_uevent_var(env, "ST=%01X", sch->st);
1038         if (ret)
1039                 return ret;
1040         ret = add_uevent_var(env, "MODALIAS=css:t%01X", sch->st);
1041         return ret;
1042 }
1043
1044 static int css_pm_prepare(struct device *dev)
1045 {
1046         struct subchannel *sch = to_subchannel(dev);
1047         struct css_driver *drv;
1048
1049         if (mutex_is_locked(&sch->reg_mutex))
1050                 return -EAGAIN;
1051         if (!sch->dev.driver)
1052                 return 0;
1053         drv = to_cssdriver(sch->dev.driver);
1054         /* Notify drivers that they may not register children. */
1055         return drv->prepare ? drv->prepare(sch) : 0;
1056 }
1057
1058 static void css_pm_complete(struct device *dev)
1059 {
1060         struct subchannel *sch = to_subchannel(dev);
1061         struct css_driver *drv;
1062
1063         if (!sch->dev.driver)
1064                 return;
1065         drv = to_cssdriver(sch->dev.driver);
1066         if (drv->complete)
1067                 drv->complete(sch);
1068 }
1069
1070 static int css_pm_freeze(struct device *dev)
1071 {
1072         struct subchannel *sch = to_subchannel(dev);
1073         struct css_driver *drv;
1074
1075         if (!sch->dev.driver)
1076                 return 0;
1077         drv = to_cssdriver(sch->dev.driver);
1078         return drv->freeze ? drv->freeze(sch) : 0;
1079 }
1080
1081 static int css_pm_thaw(struct device *dev)
1082 {
1083         struct subchannel *sch = to_subchannel(dev);
1084         struct css_driver *drv;
1085
1086         if (!sch->dev.driver)
1087                 return 0;
1088         drv = to_cssdriver(sch->dev.driver);
1089         return drv->thaw ? drv->thaw(sch) : 0;
1090 }
1091
1092 static int css_pm_restore(struct device *dev)
1093 {
1094         struct subchannel *sch = to_subchannel(dev);
1095         struct css_driver *drv;
1096
1097         if (!sch->dev.driver)
1098                 return 0;
1099         drv = to_cssdriver(sch->dev.driver);
1100         return drv->restore ? drv->restore(sch) : 0;
1101 }
1102
1103 static struct dev_pm_ops css_pm_ops = {
1104         .prepare = css_pm_prepare,
1105         .complete = css_pm_complete,
1106         .freeze = css_pm_freeze,
1107         .thaw = css_pm_thaw,
1108         .restore = css_pm_restore,
1109 };
1110
1111 struct bus_type css_bus_type = {
1112         .name     = "css",
1113         .match    = css_bus_match,
1114         .probe    = css_probe,
1115         .remove   = css_remove,
1116         .shutdown = css_shutdown,
1117         .uevent   = css_uevent,
1118         .pm = &css_pm_ops,
1119 };
1120
1121 /**
1122  * css_driver_register - register a css driver
1123  * @cdrv: css driver to register
1124  *
1125  * This is mainly a wrapper around driver_register that sets name
1126  * and bus_type in the embedded struct device_driver correctly.
1127  */
1128 int css_driver_register(struct css_driver *cdrv)
1129 {
1130         cdrv->drv.name = cdrv->name;
1131         cdrv->drv.bus = &css_bus_type;
1132         cdrv->drv.owner = cdrv->owner;
1133         return driver_register(&cdrv->drv);
1134 }
1135 EXPORT_SYMBOL_GPL(css_driver_register);
1136
1137 /**
1138  * css_driver_unregister - unregister a css driver
1139  * @cdrv: css driver to unregister
1140  *
1141  * This is a wrapper around driver_unregister.
1142  */
1143 void css_driver_unregister(struct css_driver *cdrv)
1144 {
1145         driver_unregister(&cdrv->drv);
1146 }
1147 EXPORT_SYMBOL_GPL(css_driver_unregister);
1148
1149 MODULE_LICENSE("GPL");
1150 EXPORT_SYMBOL(css_bus_type);