drivers/s390/cio/css.c

   1 /*
   2  * driver for channel subsystem
   3  *
   4  * Copyright IBM Corp. 2002, 2010
   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 <linux/proc_fs.h>
  22 #include <asm/isc.h>
  23 #include <asm/crw.h>
  24
  25 #include "css.h"
  26 #include "cio.h"
  27 #include "cio_debug.h"
  28 #include "ioasm.h"
  29 #include "chsc.h"
  30 #include "device.h"
  31 #include "idset.h"
  32 #include "chp.h"
  33
  34 int css_init_done = 0;
  35 int max_ssid;
  36
  37 struct channel_subsystem *channel_subsystems[__MAX_CSSID + 1];
  38 static struct bus_type css_bus_type;
  39
  40 int
  41 for_each_subchannel(int(*fn)(struct subchannel_id, void *), void *data)
  42 {
  43         struct subchannel_id schid;
  44         int ret;
  45
  46         init_subchannel_id(&schid);
  47         ret = -ENODEV;
  48         do {
  49                 do {
  50                         ret = fn(schid, data);
  51                         if (ret)
  52                                 break;
  53                 } while (schid.sch_no++ < __MAX_SUBCHANNEL);
  54                 schid.sch_no = 0;
  55         } while (schid.ssid++ < max_ssid);
  56         return ret;
  57 }
  58
  59 struct cb_data {
  60         void *data;
  61         struct idset *set;
  62         int (*fn_known_sch)(struct subchannel *, void *);
  63         int (*fn_unknown_sch)(struct subchannel_id, void *);
  64 };
  65
  66 static int call_fn_known_sch(struct device *dev, void *data)
  67 {
  68         struct subchannel *sch = to_subchannel(dev);
  69         struct cb_data *cb = data;
  70         int rc = 0;
  71
  72         idset_sch_del(cb->set, sch->schid);
  73         if (cb->fn_known_sch)
  74                 rc = cb->fn_known_sch(sch, cb->data);
  75         return rc;
  76 }
  77
  78 static int call_fn_unknown_sch(struct subchannel_id schid, void *data)
  79 {
  80         struct cb_data *cb = data;
  81         int rc = 0;
  82
  83         if (idset_sch_contains(cb->set, schid))
  84                 rc = cb->fn_unknown_sch(schid, cb->data);
  85         return rc;
  86 }
  87
  88 static int call_fn_all_sch(struct subchannel_id schid, void *data)
  89 {
  90         struct cb_data *cb = data;
  91         struct subchannel *sch;
  92         int rc = 0;
  93
  94         sch = get_subchannel_by_schid(schid);
  95         if (sch) {
  96                 if (cb->fn_known_sch)
  97                         rc = cb->fn_known_sch(sch, cb->data);
  98                 put_device(&sch->dev);
  99         } else {
 100                 if (cb->fn_unknown_sch)
 101                         rc = cb->fn_unknown_sch(schid, cb->data);
 102         }
 103
 104         return rc;
 105 }
 106
 107 int for_each_subchannel_staged(int (*fn_known)(struct subchannel *, void *),
 108                                int (*fn_unknown)(struct subchannel_id,
 109                                void *), void *data)
 110 {
 111         struct cb_data cb;
 112         int rc;
 113
 114         cb.data = data;
 115         cb.fn_known_sch = fn_known;
 116         cb.fn_unknown_sch = fn_unknown;
 117
 118         cb.set = idset_sch_new();
 119         if (!cb.set)
 120                 /* fall back to brute force scanning in case of oom */
 121                 return for_each_subchannel(call_fn_all_sch, &cb);
 122
 123         idset_fill(cb.set);
 124
 125         /* Process registered subchannels. */
 126         rc = bus_for_each_dev(&css_bus_type, NULL, &cb, call_fn_known_sch);
 127         if (rc)
 128                 goto out;
 129         /* Process unregistered subchannels. */
 130         if (fn_unknown)
 131                 rc = for_each_subchannel(call_fn_unknown_sch, &cb);
 132 out:
 133         idset_free(cb.set);
 134
 135         return rc;
 136 }
 137
 138 static void css_sch_todo(struct work_struct *work);
 139
 140 static struct subchannel *
 141 css_alloc_subchannel(struct subchannel_id schid)
 142 {
 143         struct subchannel *sch;
 144         int ret;
 145
 146         sch = kmalloc (sizeof (*sch), GFP_KERNEL | GFP_DMA);
 147         if (sch == NULL)
 148                 return ERR_PTR(-ENOMEM);
 149         ret = cio_validate_subchannel (sch, schid);
 150         if (ret < 0) {
 151                 kfree(sch);
 152                 return ERR_PTR(ret);
 153         }
 154         INIT_WORK(&sch->todo_work, css_sch_todo);
 155         return sch;
 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                 /* Reset intparm to zeroes. */
 166                 sch->config.intparm = 0;
 167                 cio_commit_config(sch);
 168                 kfree(sch->lock);
 169                 kfree(sch);
 170         }
 171 }
 172
 173 static int css_sch_device_register(struct subchannel *sch)
 174 {
 175         int ret;
 176
 177         mutex_lock(&sch->reg_mutex);
 178         dev_set_name(&sch->dev, "0.%x.%04x", sch->schid.ssid,
 179                      sch->schid.sch_no);
 180         ret = device_register(&sch->dev);
 181         mutex_unlock(&sch->reg_mutex);
 182         return ret;
 183 }
 184
 185 /**
 186  * css_sch_device_unregister - unregister a subchannel
 187  * @sch: subchannel to be unregistered
 188  */
 189 void css_sch_device_unregister(struct subchannel *sch)
 190 {
 191         mutex_lock(&sch->reg_mutex);
 192         if (device_is_registered(&sch->dev))
 193                 device_unregister(&sch->dev);
 194         mutex_unlock(&sch->reg_mutex);
 195 }
 196 EXPORT_SYMBOL_GPL(css_sch_device_unregister);
 197
 198 static void css_sch_todo(struct work_struct *work)
 199 {
 200         struct subchannel *sch;
 201         enum sch_todo todo;
 202
 203         sch = container_of(work, struct subchannel, todo_work);
 204         /* Find out todo. */
 205         spin_lock_irq(sch->lock);
 206         todo = sch->todo;
 207         CIO_MSG_EVENT(4, "sch_todo: sch=0.%x.%04x, todo=%d\n", sch->schid.ssid,
 208                       sch->schid.sch_no, todo);
 209         sch->todo = SCH_TODO_NOTHING;
 210         spin_unlock_irq(sch->lock);
 211         /* Perform todo. */
 212         if (todo == SCH_TODO_UNREG)
 213                 css_sch_device_unregister(sch);
 214         /* Release workqueue ref. */
 215         put_device(&sch->dev);
 216 }
 217
 218 /**
 219  * css_sched_sch_todo - schedule a subchannel operation
 220  * @sch: subchannel
 221  * @todo: todo
 222  *
 223  * Schedule the operation identified by @todo to be performed on the slow path
 224  * workqueue. Do nothing if another operation with higher priority is already
 225  * scheduled. Needs to be called with subchannel lock held.
 226  */
 227 void css_sched_sch_todo(struct subchannel *sch, enum sch_todo todo)
 228 {
 229         CIO_MSG_EVENT(4, "sch_todo: sched sch=0.%x.%04x todo=%d\n",
 230                       sch->schid.ssid, sch->schid.sch_no, todo);
 231         if (sch->todo >= todo)
 232                 return;
 233         /* Get workqueue ref. */
 234         if (!get_device(&sch->dev))
 235                 return;
 236         sch->todo = todo;
 237         if (!queue_work(cio_work_q, &sch->todo_work)) {
 238                 /* Already queued, release workqueue ref. */
 239                 put_device(&sch->dev);
 240         }
 241 }
 242
 243 static void ssd_from_pmcw(struct chsc_ssd_info *ssd, struct pmcw *pmcw)
 244 {
 245         int i;
 246         int mask;
 247
 248         memset(ssd, 0, sizeof(struct chsc_ssd_info));
 249         ssd->path_mask = pmcw->pim;
 250         for (i = 0; i < 8; i++) {
 251                 mask = 0x80 >> i;
 252                 if (pmcw->pim & mask) {
 253                         chp_id_init(&ssd->chpid[i]);
 254                         ssd->chpid[i].id = pmcw->chpid[i];
 255                 }
 256         }
 257 }
 258
 259 static void ssd_register_chpids(struct chsc_ssd_info *ssd)
 260 {
 261         int i;
 262         int mask;
 263
 264         for (i = 0; i < 8; i++) {
 265                 mask = 0x80 >> i;
 266                 if (ssd->path_mask & mask)
 267                         if (!chp_is_registered(ssd->chpid[i]))
 268                                 chp_new(ssd->chpid[i]);
 269         }
 270 }
 271
 272 void css_update_ssd_info(struct subchannel *sch)
 273 {
 274         int ret;
 275
 276         if (cio_is_console(sch->schid)) {
 277                 /* Console is initialized too early for functions requiring
 278                  * memory allocation. */
 279                 ssd_from_pmcw(&sch->ssd_info, &sch->schib.pmcw);
 280         } else {
 281                 ret = chsc_get_ssd_info(sch->schid, &sch->ssd_info);
 282                 if (ret)
 283                         ssd_from_pmcw(&sch->ssd_info, &sch->schib.pmcw);
 284                 ssd_register_chpids(&sch->ssd_info);
 285         }
 286 }
 287
 288 static ssize_t type_show(struct device *dev, struct device_attribute *attr,
 289                          char *buf)
 290 {
 291         struct subchannel *sch = to_subchannel(dev);
 292
 293         return sprintf(buf, "%01x\n", sch->st);
 294 }
 295
 296 static DEVICE_ATTR(type, 0444, type_show, NULL);
 297
 298 static ssize_t modalias_show(struct device *dev, struct device_attribute *attr,
 299                              char *buf)
 300 {
 301         struct subchannel *sch = to_subchannel(dev);
 302
 303         return sprintf(buf, "css:t%01X\n", sch->st);
 304 }
 305
 306 static DEVICE_ATTR(modalias, 0444, modalias_show, NULL);
 307
 308 static struct attribute *subch_attrs[] = {
 309         &dev_attr_type.attr,
 310         &dev_attr_modalias.attr,
 311         NULL,
 312 };
 313
 314 static struct attribute_group subch_attr_group = {
 315         .attrs = subch_attrs,
 316 };
 317
 318 static const struct attribute_group *default_subch_attr_groups[] = {
 319         &subch_attr_group,
 320         NULL,
 321 };
 322
 323 static int css_register_subchannel(struct subchannel *sch)
 324 {
 325         int ret;
 326
 327         /* Initialize the subchannel structure */
 328         sch->dev.parent = &channel_subsystems[0]->device;
 329         sch->dev.bus = &css_bus_type;
 330         sch->dev.release = &css_subchannel_release;
 331         sch->dev.groups = default_subch_attr_groups;
 332         /*
 333          * We don't want to generate uevents for I/O subchannels that don't
 334          * have a working ccw device behind them since they will be
 335          * unregistered before they can be used anyway, so we delay the add
 336          * uevent until after device recognition was successful.
 337          * Note that we suppress the uevent for all subchannel types;
 338          * the subchannel driver can decide itself when it wants to inform
 339          * userspace of its existence.
 340          */
 341         dev_set_uevent_suppress(&sch->dev, 1);
 342         css_update_ssd_info(sch);
 343         /* make it known to the system */
 344         ret = css_sch_device_register(sch);
 345         if (ret) {
 346                 CIO_MSG_EVENT(0, "Could not register sch 0.%x.%04x: %d\n",
 347                               sch->schid.ssid, sch->schid.sch_no, ret);
 348                 return ret;
 349         }
 350         if (!sch->driver) {
 351                 /*
 352                  * No driver matched. Generate the uevent now so that
 353                  * a fitting driver module may be loaded based on the
 354                  * modalias.
 355                  */
 356                 dev_set_uevent_suppress(&sch->dev, 0);
 357                 kobject_uevent(&sch->dev.kobj, KOBJ_ADD);
 358         }
 359         return ret;
 360 }
 361
 362 int css_probe_device(struct subchannel_id schid)
 363 {
 364         int ret;
 365         struct subchannel *sch;
 366
 367         if (cio_is_console(schid))
 368                 sch = cio_get_console_subchannel();
 369         else {
 370                 sch = css_alloc_subchannel(schid);
 371                 if (IS_ERR(sch))
 372                         return PTR_ERR(sch);
 373         }
 374         ret = css_register_subchannel(sch);
 375         if (ret) {
 376                 if (!cio_is_console(schid))
 377                         put_device(&sch->dev);
 378         }
 379         return ret;
 380 }
 381
 382 static int
 383 check_subchannel(struct device * dev, void * data)
 384 {
 385         struct subchannel *sch;
 386         struct subchannel_id *schid = data;
 387
 388         sch = to_subchannel(dev);
 389         return schid_equal(&sch->schid, schid);
 390 }
 391
 392 struct subchannel *
 393 get_subchannel_by_schid(struct subchannel_id schid)
 394 {
 395         struct device *dev;
 396
 397         dev = bus_find_device(&css_bus_type, NULL,
 398                               &schid, check_subchannel);
 399
 400         return dev ? to_subchannel(dev) : NULL;
 401 }
 402
 403 /**
 404  * css_sch_is_valid() - check if a subchannel is valid
 405  * @schib: subchannel information block for the subchannel
 406  */
 407 int css_sch_is_valid(struct schib *schib)
 408 {
 409         if ((schib->pmcw.st == SUBCHANNEL_TYPE_IO) && !schib->pmcw.dnv)
 410                 return 0;
 411         if ((schib->pmcw.st == SUBCHANNEL_TYPE_MSG) && !schib->pmcw.w)
 412                 return 0;
 413         return 1;
 414 }
 415 EXPORT_SYMBOL_GPL(css_sch_is_valid);
 416
 417 static int css_evaluate_new_subchannel(struct subchannel_id schid, int slow)
 418 {
 419         struct schib schib;
 420
 421         if (!slow) {
 422                 /* Will be done on the slow path. */
 423                 return -EAGAIN;
 424         }
 425         if (stsch_err(schid, &schib) || !css_sch_is_valid(&schib)) {
 426                 /* Unusable - ignore. */
 427                 return 0;
 428         }
 429         CIO_MSG_EVENT(4, "event: sch 0.%x.%04x, new\n", schid.ssid,
 430                       schid.sch_no);
 431
 432         return css_probe_device(schid);
 433 }
 434
 435 static int css_evaluate_known_subchannel(struct subchannel *sch, int slow)
 436 {
 437         int ret = 0;
 438
 439         if (sch->driver) {
 440                 if (sch->driver->sch_event)
 441                         ret = sch->driver->sch_event(sch, slow);
 442                 else
 443                         dev_dbg(&sch->dev,
 444                                 "Got subchannel machine check but "
 445                                 "no sch_event handler provided.\n");
 446         }
 447         if (ret != 0 && ret != -EAGAIN) {
 448                 CIO_MSG_EVENT(2, "eval: sch 0.%x.%04x, rc=%d\n",
 449                               sch->schid.ssid, sch->schid.sch_no, ret);
 450         }
 451         return ret;
 452 }
 453
 454 static void css_evaluate_subchannel(struct subchannel_id schid, int slow)
 455 {
 456         struct subchannel *sch;
 457         int ret;
 458
 459         sch = get_subchannel_by_schid(schid);
 460         if (sch) {
 461                 ret = css_evaluate_known_subchannel(sch, slow);
 462                 put_device(&sch->dev);
 463         } else
 464                 ret = css_evaluate_new_subchannel(schid, slow);
 465         if (ret == -EAGAIN)
 466                 css_schedule_eval(schid);
 467 }
 468
 469 static struct idset *slow_subchannel_set;
 470 static spinlock_t slow_subchannel_lock;
 471 static wait_queue_head_t css_eval_wq;
 472 static atomic_t css_eval_scheduled;
 473
 474 static int __init slow_subchannel_init(void)
 475 {
 476         spin_lock_init(&slow_subchannel_lock);
 477         atomic_set(&css_eval_scheduled, 0);
 478         init_waitqueue_head(&css_eval_wq);
 479         slow_subchannel_set = idset_sch_new();
 480         if (!slow_subchannel_set) {
 481                 CIO_MSG_EVENT(0, "could not allocate slow subchannel set\n");
 482                 return -ENOMEM;
 483         }
 484         return 0;
 485 }
 486
 487 static int slow_eval_known_fn(struct subchannel *sch, void *data)
 488 {
 489         int eval;
 490         int rc;
 491
 492         spin_lock_irq(&slow_subchannel_lock);
 493         eval = idset_sch_contains(slow_subchannel_set, sch->schid);
 494         idset_sch_del(slow_subchannel_set, sch->schid);
 495         spin_unlock_irq(&slow_subchannel_lock);
 496         if (eval) {
 497                 rc = css_evaluate_known_subchannel(sch, 1);
 498                 if (rc == -EAGAIN)
 499                         css_schedule_eval(sch->schid);
 500         }
 501         return 0;
 502 }
 503
 504 static int slow_eval_unknown_fn(struct subchannel_id schid, void *data)
 505 {
 506         int eval;
 507         int rc = 0;
 508
 509         spin_lock_irq(&slow_subchannel_lock);
 510         eval = idset_sch_contains(slow_subchannel_set, schid);
 511         idset_sch_del(slow_subchannel_set, schid);
 512         spin_unlock_irq(&slow_subchannel_lock);
 513         if (eval) {
 514                 rc = css_evaluate_new_subchannel(schid, 1);
 515                 switch (rc) {
 516                 case -EAGAIN:
 517                         css_schedule_eval(schid);
 518                         rc = 0;
 519                         break;
 520                 case -ENXIO:
 521                 case -ENOMEM:
 522                 case -EIO:
 523                         /* These should abort looping */
 524                         break;
 525                 default:
 526                         rc = 0;
 527                 }
 528         }
 529         return rc;
 530 }
 531
 532 static void css_slow_path_func(struct work_struct *unused)
 533 {
 534         unsigned long flags;
 535
 536         CIO_TRACE_EVENT(4, "slowpath");
 537         for_each_subchannel_staged(slow_eval_known_fn, slow_eval_unknown_fn,
 538                                    NULL);
 539         spin_lock_irqsave(&slow_subchannel_lock, flags);
 540         if (idset_is_empty(slow_subchannel_set)) {
 541                 atomic_set(&css_eval_scheduled, 0);
 542                 wake_up(&css_eval_wq);
 543         }
 544         spin_unlock_irqrestore(&slow_subchannel_lock, flags);
 545 }
 546
 547 static DECLARE_WORK(slow_path_work, css_slow_path_func);
 548 struct workqueue_struct *cio_work_q;
 549
 550 void css_schedule_eval(struct subchannel_id schid)
 551 {
 552         unsigned long flags;
 553
 554         spin_lock_irqsave(&slow_subchannel_lock, flags);
 555         idset_sch_add(slow_subchannel_set, schid);
 556         atomic_set(&css_eval_scheduled, 1);
 557         queue_work(cio_work_q, &slow_path_work);
 558         spin_unlock_irqrestore(&slow_subchannel_lock, flags);
 559 }
 560
 561 void css_schedule_eval_all(void)
 562 {
 563         unsigned long flags;
 564
 565         spin_lock_irqsave(&slow_subchannel_lock, flags);
 566         idset_fill(slow_subchannel_set);
 567         atomic_set(&css_eval_scheduled, 1);
 568         queue_work(cio_work_q, &slow_path_work);
 569         spin_unlock_irqrestore(&slow_subchannel_lock, flags);
 570 }
 571
 572 static int __unset_registered(struct device *dev, void *data)
 573 {
 574         struct idset *set = data;
 575         struct subchannel *sch = to_subchannel(dev);
 576
 577         idset_sch_del(set, sch->schid);
 578         return 0;
 579 }
 580
 581 static void css_schedule_eval_all_unreg(void)
 582 {
 583         unsigned long flags;
 584         struct idset *unreg_set;
 585
 586         /* Find unregistered subchannels. */
 587         unreg_set = idset_sch_new();
 588         if (!unreg_set) {
 589                 /* Fallback. */
 590                 css_schedule_eval_all();
 591                 return;
 592         }
 593         idset_fill(unreg_set);
 594         bus_for_each_dev(&css_bus_type, NULL, unreg_set, __unset_registered);
 595         /* Apply to slow_subchannel_set. */
 596         spin_lock_irqsave(&slow_subchannel_lock, flags);
 597         idset_add_set(slow_subchannel_set, unreg_set);
 598         atomic_set(&css_eval_scheduled, 1);
 599         queue_work(cio_work_q, &slow_path_work);
 600         spin_unlock_irqrestore(&slow_subchannel_lock, flags);
 601         idset_free(unreg_set);
 602 }
 603
 604 void css_wait_for_slow_path(void)
 605 {
 606         flush_workqueue(cio_work_q);
 607 }
 608
 609 /* Schedule reprobing of all unregistered subchannels. */
 610 void css_schedule_reprobe(void)
 611 {
 612         css_schedule_eval_all_unreg();
 613 }
 614 EXPORT_SYMBOL_GPL(css_schedule_reprobe);
 615
 616 /*
 617  * Called from the machine check handler for subchannel report words.
 618  */
 619 static void css_process_crw(struct crw *crw0, struct crw *crw1, int overflow)
 620 {
 621         struct subchannel_id mchk_schid;
 622         struct subchannel *sch;
 623
 624         if (overflow) {
 625                 css_schedule_eval_all();
 626                 return;
 627         }
 628         CIO_CRW_EVENT(2, "CRW0 reports slct=%d, oflw=%d, "
 629                       "chn=%d, rsc=%X, anc=%d, erc=%X, rsid=%X\n",
 630                       crw0->slct, crw0->oflw, crw0->chn, crw0->rsc, crw0->anc,
 631                       crw0->erc, crw0->rsid);
 632         if (crw1)
 633                 CIO_CRW_EVENT(2, "CRW1 reports slct=%d, oflw=%d, "
 634                               "chn=%d, rsc=%X, anc=%d, erc=%X, rsid=%X\n",
 635                               crw1->slct, crw1->oflw, crw1->chn, crw1->rsc,
 636                               crw1->anc, crw1->erc, crw1->rsid);
 637         init_subchannel_id(&mchk_schid);
 638         mchk_schid.sch_no = crw0->rsid;
 639         if (crw1)
 640                 mchk_schid.ssid = (crw1->rsid >> 4) & 3;
 641
 642         if (crw0->erc == CRW_ERC_PMOD) {
 643                 sch = get_subchannel_by_schid(mchk_schid);
 644                 if (sch) {
 645                         css_update_ssd_info(sch);
 646                         put_device(&sch->dev);
 647                 }
 648         }
 649         /*
 650          * Since we are always presented with IPI in the CRW, we have to
 651          * use stsch() to find out if the subchannel in question has come
 652          * or gone.
 653          */
 654         css_evaluate_subchannel(mchk_schid, 0);
 655 }
 656
 657 static void __init
 658 css_generate_pgid(struct channel_subsystem *css, u32 tod_high)
 659 {
 660         struct cpuid cpu_id;
 661
 662         if (css_general_characteristics.mcss) {
 663                 css->global_pgid.pgid_high.ext_cssid.version = 0x80;
 664                 css->global_pgid.pgid_high.ext_cssid.cssid = css->cssid;
 665         } else {
 666 #ifdef CONFIG_SMP
 667                 css->global_pgid.pgid_high.cpu_addr = stap();
 668 #else
 669                 css->global_pgid.pgid_high.cpu_addr = 0;
 670 #endif
 671         }
 672         get_cpu_id(&cpu_id);
 673         css->global_pgid.cpu_id = cpu_id.ident;
 674         css->global_pgid.cpu_model = cpu_id.machine;
 675         css->global_pgid.tod_high = tod_high;
 676
 677 }
 678
 679 static void
 680 channel_subsystem_release(struct device *dev)
 681 {
 682         struct channel_subsystem *css;
 683
 684         css = to_css(dev);
 685         mutex_destroy(&css->mutex);
 686         if (css->pseudo_subchannel) {
 687                 /* Implies that it has been generated but never registered. */
 688                 css_subchannel_release(&css->pseudo_subchannel->dev);
 689                 css->pseudo_subchannel = NULL;
 690         }
 691         kfree(css);
 692 }
 693
 694 static ssize_t
 695 css_cm_enable_show(struct device *dev, struct device_attribute *attr,
 696                    char *buf)
 697 {
 698         struct channel_subsystem *css = to_css(dev);
 699         int ret;
 700
 701         if (!css)
 702                 return 0;
 703         mutex_lock(&css->mutex);
 704         ret = sprintf(buf, "%x\n", css->cm_enabled);
 705         mutex_unlock(&css->mutex);
 706         return ret;
 707 }
 708
 709 static ssize_t
 710 css_cm_enable_store(struct device *dev, struct device_attribute *attr,
 711                     const char *buf, size_t count)
 712 {
 713         struct channel_subsystem *css = to_css(dev);
 714         int ret;
 715         unsigned long val;
 716
 717         ret = strict_strtoul(buf, 16, &val);
 718         if (ret)
 719                 return ret;
 720         mutex_lock(&css->mutex);
 721         switch (val) {
 722         case 0:
 723                 ret = css->cm_enabled ? chsc_secm(css, 0) : 0;
 724                 break;
 725         case 1:
 726                 ret = css->cm_enabled ? 0 : chsc_secm(css, 1);
 727                 break;
 728         default:
 729                 ret = -EINVAL;
 730         }
 731         mutex_unlock(&css->mutex);
 732         return ret < 0 ? ret : count;
 733 }
 734
 735 static DEVICE_ATTR(cm_enable, 0644, css_cm_enable_show, css_cm_enable_store);
 736
 737 static int __init setup_css(int nr)
 738 {
 739         u32 tod_high;
 740         int ret;
 741         struct channel_subsystem *css;
 742
 743         css = channel_subsystems[nr];
 744         memset(css, 0, sizeof(struct channel_subsystem));
 745         css->pseudo_subchannel =
 746                 kzalloc(sizeof(*css->pseudo_subchannel), GFP_KERNEL);
 747         if (!css->pseudo_subchannel)
 748                 return -ENOMEM;
 749         css->pseudo_subchannel->dev.parent = &css->device;
 750         css->pseudo_subchannel->dev.release = css_subchannel_release;
 751         dev_set_name(&css->pseudo_subchannel->dev, "defunct");
 752         mutex_init(&css->pseudo_subchannel->reg_mutex);
 753         ret = cio_create_sch_lock(css->pseudo_subchannel);
 754         if (ret) {
 755                 kfree(css->pseudo_subchannel);
 756                 return ret;
 757         }
 758         mutex_init(&css->mutex);
 759         css->valid = 1;
 760         css->cssid = nr;
 761         dev_set_name(&css->device, "css%x", nr);
 762         css->device.release = channel_subsystem_release;
 763         tod_high = (u32) (get_clock() >> 32);
 764         css_generate_pgid(css, tod_high);
 765         return 0;
 766 }
 767
 768 static int css_reboot_event(struct notifier_block *this,
 769                             unsigned long event,
 770                             void *ptr)
 771 {
 772         int ret, i;
 773
 774         ret = NOTIFY_DONE;
 775         for (i = 0; i <= __MAX_CSSID; i++) {
 776                 struct channel_subsystem *css;
 777
 778                 css = channel_subsystems[i];
 779                 mutex_lock(&css->mutex);
 780                 if (css->cm_enabled)
 781                         if (chsc_secm(css, 0))
 782                                 ret = NOTIFY_BAD;
 783                 mutex_unlock(&css->mutex);
 784         }
 785
 786         return ret;
 787 }
 788
 789 static struct notifier_block css_reboot_notifier = {
 790         .notifier_call = css_reboot_event,
 791 };
 792
 793 /*
 794  * Since the css devices are neither on a bus nor have a class
 795  * nor have a special device type, we cannot stop/restart channel
 796  * path measurements via the normal suspend/resume callbacks, but have
 797  * to use notifiers.
 798  */
 799 static int css_power_event(struct notifier_block *this, unsigned long event,
 800                            void *ptr)
 801 {
 802         int ret, i;
 803
 804         switch (event) {
 805         case PM_HIBERNATION_PREPARE:
 806         case PM_SUSPEND_PREPARE:
 807                 ret = NOTIFY_DONE;
 808                 for (i = 0; i <= __MAX_CSSID; i++) {
 809                         struct channel_subsystem *css;
 810
 811                         css = channel_subsystems[i];
 812                         mutex_lock(&css->mutex);
 813                         if (!css->cm_enabled) {
 814                                 mutex_unlock(&css->mutex);
 815                                 continue;
 816                         }
 817                         ret = __chsc_do_secm(css, 0);
 818                         ret = notifier_from_errno(ret);
 819                         mutex_unlock(&css->mutex);
 820                 }
 821                 break;
 822         case PM_POST_HIBERNATION:
 823         case PM_POST_SUSPEND:
 824                 ret = NOTIFY_DONE;
 825                 for (i = 0; i <= __MAX_CSSID; i++) {
 826                         struct channel_subsystem *css;
 827
 828                         css = channel_subsystems[i];
 829                         mutex_lock(&css->mutex);
 830                         if (!css->cm_enabled) {
 831                                 mutex_unlock(&css->mutex);
 832                                 continue;
 833                         }
 834                         ret = __chsc_do_secm(css, 1);
 835                         ret = notifier_from_errno(ret);
 836                         mutex_unlock(&css->mutex);
 837                 }
 838                 /* search for subchannels, which appeared during hibernation */
 839                 css_schedule_reprobe();
 840                 break;
 841         default:
 842                 ret = NOTIFY_DONE;
 843         }
 844         return ret;
 845
 846 }
 847 static struct notifier_block css_power_notifier = {
 848         .notifier_call = css_power_event,
 849 };
 850
 851 /*
 852  * Now that the driver core is running, we can setup our channel subsystem.
 853  * The struct subchannel's are created during probing (except for the
 854  * static console subchannel).
 855  */
 856 static int __init css_bus_init(void)
 857 {
 858         int ret, i;
 859
 860         ret = chsc_init();
 861         if (ret)
 862                 return ret;
 863
 864         chsc_determine_css_characteristics();
 865         /* Try to enable MSS. */
 866         ret = chsc_enable_facility(CHSC_SDA_OC_MSS);
 867         if (ret)
 868                 max_ssid = 0;
 869         else /* Success. */
 870                 max_ssid = __MAX_SSID;
 871
 872         ret = slow_subchannel_init();
 873         if (ret)
 874                 goto out;
 875
 876         ret = crw_register_handler(CRW_RSC_SCH, css_process_crw);
 877         if (ret)
 878                 goto out;
 879
 880         if ((ret = bus_register(&css_bus_type)))
 881                 goto out;
 882
 883         /* Setup css structure. */
 884         for (i = 0; i <= __MAX_CSSID; i++) {
 885                 struct channel_subsystem *css;
 886
 887                 css = kmalloc(sizeof(struct channel_subsystem), GFP_KERNEL);
 888                 if (!css) {
 889                         ret = -ENOMEM;
 890                         goto out_unregister;
 891                 }
 892                 channel_subsystems[i] = css;
 893                 ret = setup_css(i);
 894                 if (ret) {
 895                         kfree(channel_subsystems[i]);
 896                         goto out_unregister;
 897                 }
 898                 ret = device_register(&css->device);
 899                 if (ret) {
 900                         put_device(&css->device);
 901                         goto out_unregister;
 902                 }
 903                 if (css_chsc_characteristics.secm) {
 904                         ret = device_create_file(&css->device,
 905                                                  &dev_attr_cm_enable);
 906                         if (ret)
 907                                 goto out_device;
 908                 }
 909                 ret = device_register(&css->pseudo_subchannel->dev);
 910                 if (ret) {
 911                         put_device(&css->pseudo_subchannel->dev);
 912                         goto out_file;
 913                 }
 914         }
 915         ret = register_reboot_notifier(&css_reboot_notifier);
 916         if (ret)
 917                 goto out_unregister;
 918         ret = register_pm_notifier(&css_power_notifier);
 919         if (ret) {
 920                 unregister_reboot_notifier(&css_reboot_notifier);
 921                 goto out_unregister;
 922         }
 923         css_init_done = 1;
 924
 925         /* Enable default isc for I/O subchannels. */
 926         isc_register(IO_SCH_ISC);
 927
 928         return 0;
 929 out_file:
 930         if (css_chsc_characteristics.secm)
 931                 device_remove_file(&channel_subsystems[i]->device,
 932                                    &dev_attr_cm_enable);
 933 out_device:
 934         device_unregister(&channel_subsystems[i]->device);
 935 out_unregister:
 936         while (i > 0) {
 937                 struct channel_subsystem *css;
 938
 939                 i--;
 940                 css = channel_subsystems[i];
 941                 device_unregister(&css->pseudo_subchannel->dev);
 942                 css->pseudo_subchannel = NULL;
 943                 if (css_chsc_characteristics.secm)
 944                         device_remove_file(&css->device,
 945                                            &dev_attr_cm_enable);
 946                 device_unregister(&css->device);
 947         }
 948         bus_unregister(&css_bus_type);
 949 out:
 950         crw_unregister_handler(CRW_RSC_SCH);
 951         idset_free(slow_subchannel_set);
 952         chsc_init_cleanup();
 953         pr_alert("The CSS device driver initialization failed with "
 954                  "errno=%d\n", ret);
 955         return ret;
 956 }
 957
 958 static void __init css_bus_cleanup(void)
 959 {
 960         struct channel_subsystem *css;
 961         int i;
 962
 963         for (i = 0; i <= __MAX_CSSID; i++) {
 964                 css = channel_subsystems[i];
 965                 device_unregister(&css->pseudo_subchannel->dev);
 966                 css->pseudo_subchannel = NULL;
 967                 if (css_chsc_characteristics.secm)
 968                         device_remove_file(&css->device, &dev_attr_cm_enable);
 969                 device_unregister(&css->device);
 970         }
 971         bus_unregister(&css_bus_type);
 972         crw_unregister_handler(CRW_RSC_SCH);
 973         idset_free(slow_subchannel_set);
 974         chsc_init_cleanup();
 975         isc_unregister(IO_SCH_ISC);
 976 }
 977
 978 static int __init channel_subsystem_init(void)
 979 {
 980         int ret;
 981
 982         ret = css_bus_init();
 983         if (ret)
 984                 return ret;
 985         cio_work_q = create_singlethread_workqueue("cio");
 986         if (!cio_work_q) {
 987                 ret = -ENOMEM;
 988                 goto out_bus;
 989         }
 990         ret = io_subchannel_init();
 991         if (ret)
 992                 goto out_wq;
 993
 994         return ret;
 995 out_wq:
 996         destroy_workqueue(cio_work_q);
 997 out_bus:
 998         css_bus_cleanup();
 999         return ret;
1000 }
1001 subsys_initcall(channel_subsystem_init);
1002
1003 static int css_settle(struct device_driver *drv, void *unused)
1004 {
1005         struct css_driver *cssdrv = to_cssdriver(drv);
1006
1007         if (cssdrv->settle)
1008                 return cssdrv->settle();
1009         return 0;
1010 }
1011
1012 int css_complete_work(void)
1013 {
1014         int ret;
1015
1016         /* Wait for the evaluation of subchannels to finish. */
1017         ret = wait_event_interruptible(css_eval_wq,
1018                                        atomic_read(&css_eval_scheduled) == 0);
1019         if (ret)
1020                 return -EINTR;
1021         flush_workqueue(cio_work_q);
1022         /* Wait for the subchannel type specific initialization to finish */
1023         return bus_for_each_drv(&css_bus_type, NULL, NULL, css_settle);
1024 }
1025
1026
1027 /*
1028  * Wait for the initialization of devices to finish, to make sure we are
1029  * done with our setup if the search for the root device starts.
1030  */
1031 static int __init channel_subsystem_init_sync(void)
1032 {
1033         /* Start initial subchannel evaluation. */
1034         css_schedule_eval_all();
1035         css_complete_work();
1036         return 0;
1037 }
1038 subsys_initcall_sync(channel_subsystem_init_sync);
1039
1040 void channel_subsystem_reinit(void)
1041 {
1042         struct channel_path *chp;
1043         struct chp_id chpid;
1044
1045         chsc_enable_facility(CHSC_SDA_OC_MSS);
1046         chp_id_for_each(&chpid) {
1047                 chp = chpid_to_chp(chpid);
1048                 if (!chp)
1049                         continue;
1050                 chsc_determine_base_channel_path_desc(chpid, &chp->desc);
1051         }
1052 }
1053
1054 #ifdef CONFIG_PROC_FS
1055 static ssize_t cio_settle_write(struct file *file, const char __user *buf,
1056                                 size_t count, loff_t *ppos)
1057 {
1058         int ret;
1059
1060         /* Handle pending CRW's. */
1061         crw_wait_for_channel_report();
1062         ret = css_complete_work();
1063
1064         return ret ? ret : count;
1065 }
1066
1067 static const struct file_operations cio_settle_proc_fops = {
1068         .open = nonseekable_open,
1069         .write = cio_settle_write,
1070         .llseek = no_llseek,
1071 };
1072
1073 static int __init cio_settle_init(void)
1074 {
1075         struct proc_dir_entry *entry;
1076
1077         entry = proc_create("cio_settle", S_IWUSR, NULL,
1078                             &cio_settle_proc_fops);
1079         if (!entry)
1080                 return -ENOMEM;
1081         return 0;
1082 }
1083 device_initcall(cio_settle_init);
1084 #endif /*CONFIG_PROC_FS*/
1085
1086 int sch_is_pseudo_sch(struct subchannel *sch)
1087 {
1088         return sch == to_css(sch->dev.parent)->pseudo_subchannel;
1089 }
1090
1091 static int css_bus_match(struct device *dev, struct device_driver *drv)
1092 {
1093         struct subchannel *sch = to_subchannel(dev);
1094         struct css_driver *driver = to_cssdriver(drv);
1095         struct css_device_id *id;
1096
1097         for (id = driver->subchannel_type; id->match_flags; id++) {
1098                 if (sch->st == id->type)
1099                         return 1;
1100         }
1101
1102         return 0;
1103 }
1104
1105 static int css_probe(struct device *dev)
1106 {
1107         struct subchannel *sch;
1108         int ret;
1109
1110         sch = to_subchannel(dev);
1111         sch->driver = to_cssdriver(dev->driver);
1112         ret = sch->driver->probe ? sch->driver->probe(sch) : 0;
1113         if (ret)
1114                 sch->driver = NULL;
1115         return ret;
1116 }
1117
1118 static int css_remove(struct device *dev)
1119 {
1120         struct subchannel *sch;
1121         int ret;
1122
1123         sch = to_subchannel(dev);
1124         ret = sch->driver->remove ? sch->driver->remove(sch) : 0;
1125         sch->driver = NULL;
1126         return ret;
1127 }
1128
1129 static void css_shutdown(struct device *dev)
1130 {
1131         struct subchannel *sch;
1132
1133         sch = to_subchannel(dev);
1134         if (sch->driver && sch->driver->shutdown)
1135                 sch->driver->shutdown(sch);
1136 }
1137
1138 static int css_uevent(struct device *dev, struct kobj_uevent_env *env)
1139 {
1140         struct subchannel *sch = to_subchannel(dev);
1141         int ret;
1142
1143         ret = add_uevent_var(env, "ST=%01X", sch->st);
1144         if (ret)
1145                 return ret;
1146         ret = add_uevent_var(env, "MODALIAS=css:t%01X", sch->st);
1147         return ret;
1148 }
1149
1150 static int css_pm_prepare(struct device *dev)
1151 {
1152         struct subchannel *sch = to_subchannel(dev);
1153         struct css_driver *drv;
1154
1155         if (mutex_is_locked(&sch->reg_mutex))
1156                 return -EAGAIN;
1157         if (!sch->dev.driver)
1158                 return 0;
1159         drv = to_cssdriver(sch->dev.driver);
1160         /* Notify drivers that they may not register children. */
1161         return drv->prepare ? drv->prepare(sch) : 0;
1162 }
1163
1164 static void css_pm_complete(struct device *dev)
1165 {
1166         struct subchannel *sch = to_subchannel(dev);
1167         struct css_driver *drv;
1168
1169         if (!sch->dev.driver)
1170                 return;
1171         drv = to_cssdriver(sch->dev.driver);
1172         if (drv->complete)
1173                 drv->complete(sch);
1174 }
1175
1176 static int css_pm_freeze(struct device *dev)
1177 {
1178         struct subchannel *sch = to_subchannel(dev);
1179         struct css_driver *drv;
1180
1181         if (!sch->dev.driver)
1182                 return 0;
1183         drv = to_cssdriver(sch->dev.driver);
1184         return drv->freeze ? drv->freeze(sch) : 0;
1185 }
1186
1187 static int css_pm_thaw(struct device *dev)
1188 {
1189         struct subchannel *sch = to_subchannel(dev);
1190         struct css_driver *drv;
1191
1192         if (!sch->dev.driver)
1193                 return 0;
1194         drv = to_cssdriver(sch->dev.driver);
1195         return drv->thaw ? drv->thaw(sch) : 0;
1196 }
1197
1198 static int css_pm_restore(struct device *dev)
1199 {
1200         struct subchannel *sch = to_subchannel(dev);
1201         struct css_driver *drv;
1202
1203         css_update_ssd_info(sch);
1204         if (!sch->dev.driver)
1205                 return 0;
1206         drv = to_cssdriver(sch->dev.driver);
1207         return drv->restore ? drv->restore(sch) : 0;
1208 }
1209
1210 static const struct dev_pm_ops css_pm_ops = {
1211         .prepare = css_pm_prepare,
1212         .complete = css_pm_complete,
1213         .freeze = css_pm_freeze,
1214         .thaw = css_pm_thaw,
1215         .restore = css_pm_restore,
1216 };
1217
1218 static struct bus_type css_bus_type = {
1219         .name     = "css",
1220         .match    = css_bus_match,
1221         .probe    = css_probe,
1222         .remove   = css_remove,
1223         .shutdown = css_shutdown,
1224         .uevent   = css_uevent,
1225         .pm = &css_pm_ops,
1226 };
1227
1228 /**
1229  * css_driver_register - register a css driver
1230  * @cdrv: css driver to register
1231  *
1232  * This is mainly a wrapper around driver_register that sets name
1233  * and bus_type in the embedded struct device_driver correctly.
1234  */
1235 int css_driver_register(struct css_driver *cdrv)
1236 {
1237         cdrv->drv.bus = &css_bus_type;
1238         return driver_register(&cdrv->drv);
1239 }
1240 EXPORT_SYMBOL_GPL(css_driver_register);
1241
1242 /**
1243  * css_driver_unregister - unregister a css driver
1244  * @cdrv: css driver to unregister
1245  *
1246  * This is a wrapper around driver_unregister.
1247  */
1248 void css_driver_unregister(struct css_driver *cdrv)
1249 {
1250         driver_unregister(&cdrv->drv);
1251 }
1252 EXPORT_SYMBOL_GPL(css_driver_unregister);
1253
1254 MODULE_LICENSE("GPL");