drivers/s390/cio/css.c

   1 // SPDX-License-Identifier: GPL-2.0
   2 /*
   3  * driver for channel subsystem
   4  *
   5  * Copyright IBM Corp. 2002, 2010
   6  *
   7  * Author(s): Arnd Bergmann (arndb@de.ibm.com)
   8  *            Cornelia Huck (cornelia.huck@de.ibm.com)
   9  */
  10
  11 #define KMSG_COMPONENT "cio"
  12 #define pr_fmt(fmt) KMSG_COMPONENT ": " fmt
  13
  14 #include <linux/export.h>
  15 #include <linux/init.h>
  16 #include <linux/device.h>
  17 #include <linux/slab.h>
  18 #include <linux/errno.h>
  19 #include <linux/list.h>
  20 #include <linux/reboot.h>
  21 #include <linux/suspend.h>
  22 #include <linux/proc_fs.h>
  23 #include <asm/isc.h>
  24 #include <asm/crw.h>
  25
  26 #include "css.h"
  27 #include "cio.h"
  28 #include "blacklist.h"
  29 #include "cio_debug.h"
  30 #include "ioasm.h"
  31 #include "chsc.h"
  32 #include "device.h"
  33 #include "idset.h"
  34 #include "chp.h"
  35
  36 int css_init_done = 0;
  37 int max_ssid;
  38
  39 #define MAX_CSS_IDX 0
  40 struct channel_subsystem *channel_subsystems[MAX_CSS_IDX + 1];
  41 static struct bus_type css_bus_type;
  42
  43 int
  44 for_each_subchannel(int(*fn)(struct subchannel_id, void *), void *data)
  45 {
  46         struct subchannel_id schid;
  47         int ret;
  48
  49         init_subchannel_id(&schid);
  50         do {
  51                 do {
  52                         ret = fn(schid, data);
  53                         if (ret)
  54                                 break;
  55                 } while (schid.sch_no++ < __MAX_SUBCHANNEL);
  56                 schid.sch_no = 0;
  57         } while (schid.ssid++ < max_ssid);
  58         return ret;
  59 }
  60
  61 struct cb_data {
  62         void *data;
  63         struct idset *set;
  64         int (*fn_known_sch)(struct subchannel *, void *);
  65         int (*fn_unknown_sch)(struct subchannel_id, void *);
  66 };
  67
  68 static int call_fn_known_sch(struct device *dev, void *data)
  69 {
  70         struct subchannel *sch = to_subchannel(dev);
  71         struct cb_data *cb = data;
  72         int rc = 0;
  73
  74         if (cb->set)
  75                 idset_sch_del(cb->set, sch->schid);
  76         if (cb->fn_known_sch)
  77                 rc = cb->fn_known_sch(sch, cb->data);
  78         return rc;
  79 }
  80
  81 static int call_fn_unknown_sch(struct subchannel_id schid, void *data)
  82 {
  83         struct cb_data *cb = data;
  84         int rc = 0;
  85
  86         if (idset_sch_contains(cb->set, schid))
  87                 rc = cb->fn_unknown_sch(schid, cb->data);
  88         return rc;
  89 }
  90
  91 static int call_fn_all_sch(struct subchannel_id schid, void *data)
  92 {
  93         struct cb_data *cb = data;
  94         struct subchannel *sch;
  95         int rc = 0;
  96
  97         sch = get_subchannel_by_schid(schid);
  98         if (sch) {
  99                 if (cb->fn_known_sch)
 100                         rc = cb->fn_known_sch(sch, cb->data);
 101                 put_device(&sch->dev);
 102         } else {
 103                 if (cb->fn_unknown_sch)
 104                         rc = cb->fn_unknown_sch(schid, cb->data);
 105         }
 106
 107         return rc;
 108 }
 109
 110 int for_each_subchannel_staged(int (*fn_known)(struct subchannel *, void *),
 111                                int (*fn_unknown)(struct subchannel_id,
 112                                void *), void *data)
 113 {
 114         struct cb_data cb;
 115         int rc;
 116
 117         cb.data = data;
 118         cb.fn_known_sch = fn_known;
 119         cb.fn_unknown_sch = fn_unknown;
 120
 121         if (fn_known && !fn_unknown) {
 122                 /* Skip idset allocation in case of known-only loop. */
 123                 cb.set = NULL;
 124                 return bus_for_each_dev(&css_bus_type, NULL, &cb,
 125                                         call_fn_known_sch);
 126         }
 127
 128         cb.set = idset_sch_new();
 129         if (!cb.set)
 130                 /* fall back to brute force scanning in case of oom */
 131                 return for_each_subchannel(call_fn_all_sch, &cb);
 132
 133         idset_fill(cb.set);
 134
 135         /* Process registered subchannels. */
 136         rc = bus_for_each_dev(&css_bus_type, NULL, &cb, call_fn_known_sch);
 137         if (rc)
 138                 goto out;
 139         /* Process unregistered subchannels. */
 140         if (fn_unknown)
 141                 rc = for_each_subchannel(call_fn_unknown_sch, &cb);
 142 out:
 143         idset_free(cb.set);
 144
 145         return rc;
 146 }
 147
 148 static void css_sch_todo(struct work_struct *work);
 149
 150 static int css_sch_create_locks(struct subchannel *sch)
 151 {
 152         sch->lock = kmalloc(sizeof(*sch->lock), GFP_KERNEL);
 153         if (!sch->lock)
 154                 return -ENOMEM;
 155
 156         spin_lock_init(sch->lock);
 157         mutex_init(&sch->reg_mutex);
 158
 159         return 0;
 160 }
 161
 162 static void css_subchannel_release(struct device *dev)
 163 {
 164         struct subchannel *sch = to_subchannel(dev);
 165
 166         sch->config.intparm = 0;
 167         cio_commit_config(sch);
 168         kfree(sch->lock);
 169         kfree(sch);
 170 }
 171
 172 static int css_validate_subchannel(struct subchannel_id schid,
 173                                    struct schib *schib)
 174 {
 175         int err;
 176
 177         switch (schib->pmcw.st) {
 178         case SUBCHANNEL_TYPE_IO:
 179         case SUBCHANNEL_TYPE_MSG:
 180                 if (!css_sch_is_valid(schib))
 181                         err = -ENODEV;
 182                 else if (is_blacklisted(schid.ssid, schib->pmcw.dev)) {
 183                         CIO_MSG_EVENT(6, "Blacklisted device detected "
 184                                       "at devno %04X, subchannel set %x\n",
 185                                       schib->pmcw.dev, schid.ssid);
 186                         err = -ENODEV;
 187                 } else
 188                         err = 0;
 189                 break;
 190         default:
 191                 err = 0;
 192         }
 193         if (err)
 194                 goto out;
 195
 196         CIO_MSG_EVENT(4, "Subchannel 0.%x.%04x reports subchannel type %04X\n",
 197                       schid.ssid, schid.sch_no, schib->pmcw.st);
 198 out:
 199         return err;
 200 }
 201
 202 struct subchannel *css_alloc_subchannel(struct subchannel_id schid,
 203                                         struct schib *schib)
 204 {
 205         struct subchannel *sch;
 206         int ret;
 207
 208         ret = css_validate_subchannel(schid, schib);
 209         if (ret < 0)
 210                 return ERR_PTR(ret);
 211
 212         sch = kzalloc(sizeof(*sch), GFP_KERNEL | GFP_DMA);
 213         if (!sch)
 214                 return ERR_PTR(-ENOMEM);
 215
 216         sch->schid = schid;
 217         sch->schib = *schib;
 218         sch->st = schib->pmcw.st;
 219
 220         ret = css_sch_create_locks(sch);
 221         if (ret)
 222                 goto err;
 223
 224         INIT_WORK(&sch->todo_work, css_sch_todo);
 225         sch->dev.release = &css_subchannel_release;
 226         device_initialize(&sch->dev);
 227         return sch;
 228
 229 err:
 230         kfree(sch);
 231         return ERR_PTR(ret);
 232 }
 233
 234 static int css_sch_device_register(struct subchannel *sch)
 235 {
 236         int ret;
 237
 238         mutex_lock(&sch->reg_mutex);
 239         dev_set_name(&sch->dev, "0.%x.%04x", sch->schid.ssid,
 240                      sch->schid.sch_no);
 241         ret = device_add(&sch->dev);
 242         mutex_unlock(&sch->reg_mutex);
 243         return ret;
 244 }
 245
 246 /**
 247  * css_sch_device_unregister - unregister a subchannel
 248  * @sch: subchannel to be unregistered
 249  */
 250 void css_sch_device_unregister(struct subchannel *sch)
 251 {
 252         mutex_lock(&sch->reg_mutex);
 253         if (device_is_registered(&sch->dev))
 254                 device_unregister(&sch->dev);
 255         mutex_unlock(&sch->reg_mutex);
 256 }
 257 EXPORT_SYMBOL_GPL(css_sch_device_unregister);
 258
 259 static void ssd_from_pmcw(struct chsc_ssd_info *ssd, struct pmcw *pmcw)
 260 {
 261         int i;
 262         int mask;
 263
 264         memset(ssd, 0, sizeof(struct chsc_ssd_info));
 265         ssd->path_mask = pmcw->pim;
 266         for (i = 0; i < 8; i++) {
 267                 mask = 0x80 >> i;
 268                 if (pmcw->pim & mask) {
 269                         chp_id_init(&ssd->chpid[i]);
 270                         ssd->chpid[i].id = pmcw->chpid[i];
 271                 }
 272         }
 273 }
 274
 275 static void ssd_register_chpids(struct chsc_ssd_info *ssd)
 276 {
 277         int i;
 278         int mask;
 279
 280         for (i = 0; i < 8; i++) {
 281                 mask = 0x80 >> i;
 282                 if (ssd->path_mask & mask)
 283                         chp_new(ssd->chpid[i]);
 284         }
 285 }
 286
 287 void css_update_ssd_info(struct subchannel *sch)
 288 {
 289         int ret;
 290
 291         ret = chsc_get_ssd_info(sch->schid, &sch->ssd_info);
 292         if (ret)
 293                 ssd_from_pmcw(&sch->ssd_info, &sch->schib.pmcw);
 294
 295         ssd_register_chpids(&sch->ssd_info);
 296 }
 297
 298 static ssize_t type_show(struct device *dev, struct device_attribute *attr,
 299                          char *buf)
 300 {
 301         struct subchannel *sch = to_subchannel(dev);
 302
 303         return sprintf(buf, "%01x\n", sch->st);
 304 }
 305
 306 static DEVICE_ATTR_RO(type);
 307
 308 static ssize_t modalias_show(struct device *dev, struct device_attribute *attr,
 309                              char *buf)
 310 {
 311         struct subchannel *sch = to_subchannel(dev);
 312
 313         return sprintf(buf, "css:t%01X\n", sch->st);
 314 }
 315
 316 static DEVICE_ATTR_RO(modalias);
 317
 318 static struct attribute *subch_attrs[] = {
 319         &dev_attr_type.attr,
 320         &dev_attr_modalias.attr,
 321         NULL,
 322 };
 323
 324 static struct attribute_group subch_attr_group = {
 325         .attrs = subch_attrs,
 326 };
 327
 328 static const struct attribute_group *default_subch_attr_groups[] = {
 329         &subch_attr_group,
 330         NULL,
 331 };
 332
 333 static ssize_t chpids_show(struct device *dev,
 334                            struct device_attribute *attr,
 335                            char *buf)
 336 {
 337         struct subchannel *sch = to_subchannel(dev);
 338         struct chsc_ssd_info *ssd = &sch->ssd_info;
 339         ssize_t ret = 0;
 340         int mask;
 341         int chp;
 342
 343         for (chp = 0; chp < 8; chp++) {
 344                 mask = 0x80 >> chp;
 345                 if (ssd->path_mask & mask)
 346                         ret += sprintf(buf + ret, "%02x ", ssd->chpid[chp].id);
 347                 else
 348                         ret += sprintf(buf + ret, "00 ");
 349         }
 350         ret += sprintf(buf + ret, "\n");
 351         return ret;
 352 }
 353 static DEVICE_ATTR_RO(chpids);
 354
 355 static ssize_t pimpampom_show(struct device *dev,
 356                               struct device_attribute *attr,
 357                               char *buf)
 358 {
 359         struct subchannel *sch = to_subchannel(dev);
 360         struct pmcw *pmcw = &sch->schib.pmcw;
 361
 362         return sprintf(buf, "%02x %02x %02x\n",
 363                        pmcw->pim, pmcw->pam, pmcw->pom);
 364 }
 365 static DEVICE_ATTR_RO(pimpampom);
 366
 367 static ssize_t dev_busid_show(struct device *dev,
 368                               struct device_attribute *attr,
 369                               char *buf)
 370 {
 371         struct subchannel *sch = to_subchannel(dev);
 372         struct pmcw *pmcw = &sch->schib.pmcw;
 373
 374         if ((pmcw->st == SUBCHANNEL_TYPE_IO && pmcw->dnv) ||
 375             (pmcw->st == SUBCHANNEL_TYPE_MSG && pmcw->w))
 376                 return sysfs_emit(buf, "0.%x.%04x\n", sch->schid.ssid,
 377                                   pmcw->dev);
 378         else
 379                 return sysfs_emit(buf, "none\n");
 380 }
 381 static DEVICE_ATTR_RO(dev_busid);
 382
 383 static struct attribute *io_subchannel_type_attrs[] = {
 384         &dev_attr_chpids.attr,
 385         &dev_attr_pimpampom.attr,
 386         &dev_attr_dev_busid.attr,
 387         NULL,
 388 };
 389 ATTRIBUTE_GROUPS(io_subchannel_type);
 390
 391 static const struct device_type io_subchannel_type = {
 392         .groups = io_subchannel_type_groups,
 393 };
 394
 395 int css_register_subchannel(struct subchannel *sch)
 396 {
 397         int ret;
 398
 399         /* Initialize the subchannel structure */
 400         sch->dev.parent = &channel_subsystems[0]->device;
 401         sch->dev.bus = &css_bus_type;
 402         sch->dev.groups = default_subch_attr_groups;
 403
 404         if (sch->st == SUBCHANNEL_TYPE_IO)
 405                 sch->dev.type = &io_subchannel_type;
 406
 407         /*
 408          * We don't want to generate uevents for I/O subchannels that don't
 409          * have a working ccw device behind them since they will be
 410          * unregistered before they can be used anyway, so we delay the add
 411          * uevent until after device recognition was successful.
 412          * Note that we suppress the uevent for all subchannel types;
 413          * the subchannel driver can decide itself when it wants to inform
 414          * userspace of its existence.
 415          */
 416         dev_set_uevent_suppress(&sch->dev, 1);
 417         css_update_ssd_info(sch);
 418         /* make it known to the system */
 419         ret = css_sch_device_register(sch);
 420         if (ret) {
 421                 CIO_MSG_EVENT(0, "Could not register sch 0.%x.%04x: %d\n",
 422                               sch->schid.ssid, sch->schid.sch_no, ret);
 423                 return ret;
 424         }
 425         if (!sch->driver) {
 426                 /*
 427                  * No driver matched. Generate the uevent now so that
 428                  * a fitting driver module may be loaded based on the
 429                  * modalias.
 430                  */
 431                 dev_set_uevent_suppress(&sch->dev, 0);
 432                 kobject_uevent(&sch->dev.kobj, KOBJ_ADD);
 433         }
 434         return ret;
 435 }
 436
 437 static int css_probe_device(struct subchannel_id schid, struct schib *schib)
 438 {
 439         struct subchannel *sch;
 440         int ret;
 441
 442         sch = css_alloc_subchannel(schid, schib);
 443         if (IS_ERR(sch))
 444                 return PTR_ERR(sch);
 445
 446         ret = css_register_subchannel(sch);
 447         if (ret)
 448                 put_device(&sch->dev);
 449
 450         return ret;
 451 }
 452
 453 static int
 454 check_subchannel(struct device * dev, void * data)
 455 {
 456         struct subchannel *sch;
 457         struct subchannel_id *schid = data;
 458
 459         sch = to_subchannel(dev);
 460         return schid_equal(&sch->schid, schid);
 461 }
 462
 463 struct subchannel *
 464 get_subchannel_by_schid(struct subchannel_id schid)
 465 {
 466         struct device *dev;
 467
 468         dev = bus_find_device(&css_bus_type, NULL,
 469                               &schid, check_subchannel);
 470
 471         return dev ? to_subchannel(dev) : NULL;
 472 }
 473
 474 /**
 475  * css_sch_is_valid() - check if a subchannel is valid
 476  * @schib: subchannel information block for the subchannel
 477  */
 478 int css_sch_is_valid(struct schib *schib)
 479 {
 480         if ((schib->pmcw.st == SUBCHANNEL_TYPE_IO) && !schib->pmcw.dnv)
 481                 return 0;
 482         if ((schib->pmcw.st == SUBCHANNEL_TYPE_MSG) && !schib->pmcw.w)
 483                 return 0;
 484         return 1;
 485 }
 486 EXPORT_SYMBOL_GPL(css_sch_is_valid);
 487
 488 static int css_evaluate_new_subchannel(struct subchannel_id schid, int slow)
 489 {
 490         struct schib schib;
 491         int ccode;
 492
 493         if (!slow) {
 494                 /* Will be done on the slow path. */
 495                 return -EAGAIN;
 496         }
 497         /*
 498          * The first subchannel that is not-operational (ccode==3)
 499          * indicates that there aren't any more devices available.
 500          * If stsch gets an exception, it means the current subchannel set
 501          * is not valid.
 502          */
 503         ccode = stsch(schid, &schib);
 504         if (ccode)
 505                 return (ccode == 3) ? -ENXIO : ccode;
 506
 507         return css_probe_device(schid, &schib);
 508 }
 509
 510 static int css_evaluate_known_subchannel(struct subchannel *sch, int slow)
 511 {
 512         int ret = 0;
 513
 514         if (sch->driver) {
 515                 if (sch->driver->sch_event)
 516                         ret = sch->driver->sch_event(sch, slow);
 517                 else
 518                         dev_dbg(&sch->dev,
 519                                 "Got subchannel machine check but "
 520                                 "no sch_event handler provided.\n");
 521         }
 522         if (ret != 0 && ret != -EAGAIN) {
 523                 CIO_MSG_EVENT(2, "eval: sch 0.%x.%04x, rc=%d\n",
 524                               sch->schid.ssid, sch->schid.sch_no, ret);
 525         }
 526         return ret;
 527 }
 528
 529 static void css_evaluate_subchannel(struct subchannel_id schid, int slow)
 530 {
 531         struct subchannel *sch;
 532         int ret;
 533
 534         sch = get_subchannel_by_schid(schid);
 535         if (sch) {
 536                 ret = css_evaluate_known_subchannel(sch, slow);
 537                 put_device(&sch->dev);
 538         } else
 539                 ret = css_evaluate_new_subchannel(schid, slow);
 540         if (ret == -EAGAIN)
 541                 css_schedule_eval(schid);
 542 }
 543
 544 /**
 545  * css_sched_sch_todo - schedule a subchannel operation
 546  * @sch: subchannel
 547  * @todo: todo
 548  *
 549  * Schedule the operation identified by @todo to be performed on the slow path
 550  * workqueue. Do nothing if another operation with higher priority is already
 551  * scheduled. Needs to be called with subchannel lock held.
 552  */
 553 void css_sched_sch_todo(struct subchannel *sch, enum sch_todo todo)
 554 {
 555         CIO_MSG_EVENT(4, "sch_todo: sched sch=0.%x.%04x todo=%d\n",
 556                       sch->schid.ssid, sch->schid.sch_no, todo);
 557         if (sch->todo >= todo)
 558                 return;
 559         /* Get workqueue ref. */
 560         if (!get_device(&sch->dev))
 561                 return;
 562         sch->todo = todo;
 563         if (!queue_work(cio_work_q, &sch->todo_work)) {
 564                 /* Already queued, release workqueue ref. */
 565                 put_device(&sch->dev);
 566         }
 567 }
 568 EXPORT_SYMBOL_GPL(css_sched_sch_todo);
 569
 570 static void css_sch_todo(struct work_struct *work)
 571 {
 572         struct subchannel *sch;
 573         enum sch_todo todo;
 574         int ret;
 575
 576         sch = container_of(work, struct subchannel, todo_work);
 577         /* Find out todo. */
 578         spin_lock_irq(sch->lock);
 579         todo = sch->todo;
 580         CIO_MSG_EVENT(4, "sch_todo: sch=0.%x.%04x, todo=%d\n", sch->schid.ssid,
 581                       sch->schid.sch_no, todo);
 582         sch->todo = SCH_TODO_NOTHING;
 583         spin_unlock_irq(sch->lock);
 584         /* Perform todo. */
 585         switch (todo) {
 586         case SCH_TODO_NOTHING:
 587                 break;
 588         case SCH_TODO_EVAL:
 589                 ret = css_evaluate_known_subchannel(sch, 1);
 590                 if (ret == -EAGAIN) {
 591                         spin_lock_irq(sch->lock);
 592                         css_sched_sch_todo(sch, todo);
 593                         spin_unlock_irq(sch->lock);
 594                 }
 595                 break;
 596         case SCH_TODO_UNREG:
 597                 css_sch_device_unregister(sch);
 598                 break;
 599         }
 600         /* Release workqueue ref. */
 601         put_device(&sch->dev);
 602 }
 603
 604 static struct idset *slow_subchannel_set;
 605 static spinlock_t slow_subchannel_lock;
 606 static wait_queue_head_t css_eval_wq;
 607 static atomic_t css_eval_scheduled;
 608
 609 static int __init slow_subchannel_init(void)
 610 {
 611         spin_lock_init(&slow_subchannel_lock);
 612         atomic_set(&css_eval_scheduled, 0);
 613         init_waitqueue_head(&css_eval_wq);
 614         slow_subchannel_set = idset_sch_new();
 615         if (!slow_subchannel_set) {
 616                 CIO_MSG_EVENT(0, "could not allocate slow subchannel set\n");
 617                 return -ENOMEM;
 618         }
 619         return 0;
 620 }
 621
 622 static int slow_eval_known_fn(struct subchannel *sch, void *data)
 623 {
 624         int eval;
 625         int rc;
 626
 627         spin_lock_irq(&slow_subchannel_lock);
 628         eval = idset_sch_contains(slow_subchannel_set, sch->schid);
 629         idset_sch_del(slow_subchannel_set, sch->schid);
 630         spin_unlock_irq(&slow_subchannel_lock);
 631         if (eval) {
 632                 rc = css_evaluate_known_subchannel(sch, 1);
 633                 if (rc == -EAGAIN)
 634                         css_schedule_eval(sch->schid);
 635                 /*
 636                  * The loop might take long time for platforms with lots of
 637                  * known devices. Allow scheduling here.
 638                  */
 639                 cond_resched();
 640         }
 641         return 0;
 642 }
 643
 644 static int slow_eval_unknown_fn(struct subchannel_id schid, void *data)
 645 {
 646         int eval;
 647         int rc = 0;
 648
 649         spin_lock_irq(&slow_subchannel_lock);
 650         eval = idset_sch_contains(slow_subchannel_set, schid);
 651         idset_sch_del(slow_subchannel_set, schid);
 652         spin_unlock_irq(&slow_subchannel_lock);
 653         if (eval) {
 654                 rc = css_evaluate_new_subchannel(schid, 1);
 655                 switch (rc) {
 656                 case -EAGAIN:
 657                         css_schedule_eval(schid);
 658                         rc = 0;
 659                         break;
 660                 case -ENXIO:
 661                 case -ENOMEM:
 662                 case -EIO:
 663                         /* These should abort looping */
 664                         spin_lock_irq(&slow_subchannel_lock);
 665                         idset_sch_del_subseq(slow_subchannel_set, schid);
 666                         spin_unlock_irq(&slow_subchannel_lock);
 667                         break;
 668                 default:
 669                         rc = 0;
 670                 }
 671                 /* Allow scheduling here since the containing loop might
 672                  * take a while.  */
 673                 cond_resched();
 674         }
 675         return rc;
 676 }
 677
 678 static void css_slow_path_func(struct work_struct *unused)
 679 {
 680         unsigned long flags;
 681
 682         CIO_TRACE_EVENT(4, "slowpath");
 683         for_each_subchannel_staged(slow_eval_known_fn, slow_eval_unknown_fn,
 684                                    NULL);
 685         spin_lock_irqsave(&slow_subchannel_lock, flags);
 686         if (idset_is_empty(slow_subchannel_set)) {
 687                 atomic_set(&css_eval_scheduled, 0);
 688                 wake_up(&css_eval_wq);
 689         }
 690         spin_unlock_irqrestore(&slow_subchannel_lock, flags);
 691 }
 692
 693 static DECLARE_DELAYED_WORK(slow_path_work, css_slow_path_func);
 694 struct workqueue_struct *cio_work_q;
 695
 696 void css_schedule_eval(struct subchannel_id schid)
 697 {
 698         unsigned long flags;
 699
 700         spin_lock_irqsave(&slow_subchannel_lock, flags);
 701         idset_sch_add(slow_subchannel_set, schid);
 702         atomic_set(&css_eval_scheduled, 1);
 703         queue_delayed_work(cio_work_q, &slow_path_work, 0);
 704         spin_unlock_irqrestore(&slow_subchannel_lock, flags);
 705 }
 706
 707 void css_schedule_eval_all(void)
 708 {
 709         unsigned long flags;
 710
 711         spin_lock_irqsave(&slow_subchannel_lock, flags);
 712         idset_fill(slow_subchannel_set);
 713         atomic_set(&css_eval_scheduled, 1);
 714         queue_delayed_work(cio_work_q, &slow_path_work, 0);
 715         spin_unlock_irqrestore(&slow_subchannel_lock, flags);
 716 }
 717
 718 static int __unset_registered(struct device *dev, void *data)
 719 {
 720         struct idset *set = data;
 721         struct subchannel *sch = to_subchannel(dev);
 722
 723         idset_sch_del(set, sch->schid);
 724         return 0;
 725 }
 726
 727 void css_schedule_eval_all_unreg(unsigned long delay)
 728 {
 729         unsigned long flags;
 730         struct idset *unreg_set;
 731
 732         /* Find unregistered subchannels. */
 733         unreg_set = idset_sch_new();
 734         if (!unreg_set) {
 735                 /* Fallback. */
 736                 css_schedule_eval_all();
 737                 return;
 738         }
 739         idset_fill(unreg_set);
 740         bus_for_each_dev(&css_bus_type, NULL, unreg_set, __unset_registered);
 741         /* Apply to slow_subchannel_set. */
 742         spin_lock_irqsave(&slow_subchannel_lock, flags);
 743         idset_add_set(slow_subchannel_set, unreg_set);
 744         atomic_set(&css_eval_scheduled, 1);
 745         queue_delayed_work(cio_work_q, &slow_path_work, delay);
 746         spin_unlock_irqrestore(&slow_subchannel_lock, flags);
 747         idset_free(unreg_set);
 748 }
 749
 750 void css_wait_for_slow_path(void)
 751 {
 752         flush_workqueue(cio_work_q);
 753 }
 754
 755 /* Schedule reprobing of all unregistered subchannels. */
 756 void css_schedule_reprobe(void)
 757 {
 758         /* Schedule with a delay to allow merging of subsequent calls. */
 759         css_schedule_eval_all_unreg(1 * HZ);
 760 }
 761 EXPORT_SYMBOL_GPL(css_schedule_reprobe);
 762
 763 /*
 764  * Called from the machine check handler for subchannel report words.
 765  */
 766 static void css_process_crw(struct crw *crw0, struct crw *crw1, int overflow)
 767 {
 768         struct subchannel_id mchk_schid;
 769         struct subchannel *sch;
 770
 771         if (overflow) {
 772                 css_schedule_eval_all();
 773                 return;
 774         }
 775         CIO_CRW_EVENT(2, "CRW0 reports slct=%d, oflw=%d, "
 776                       "chn=%d, rsc=%X, anc=%d, erc=%X, rsid=%X\n",
 777                       crw0->slct, crw0->oflw, crw0->chn, crw0->rsc, crw0->anc,
 778                       crw0->erc, crw0->rsid);
 779         if (crw1)
 780                 CIO_CRW_EVENT(2, "CRW1 reports slct=%d, oflw=%d, "
 781                               "chn=%d, rsc=%X, anc=%d, erc=%X, rsid=%X\n",
 782                               crw1->slct, crw1->oflw, crw1->chn, crw1->rsc,
 783                               crw1->anc, crw1->erc, crw1->rsid);
 784         init_subchannel_id(&mchk_schid);
 785         mchk_schid.sch_no = crw0->rsid;
 786         if (crw1)
 787                 mchk_schid.ssid = (crw1->rsid >> 4) & 3;
 788
 789         if (crw0->erc == CRW_ERC_PMOD) {
 790                 sch = get_subchannel_by_schid(mchk_schid);
 791                 if (sch) {
 792                         css_update_ssd_info(sch);
 793                         put_device(&sch->dev);
 794                 }
 795         }
 796         /*
 797          * Since we are always presented with IPI in the CRW, we have to
 798          * use stsch() to find out if the subchannel in question has come
 799          * or gone.
 800          */
 801         css_evaluate_subchannel(mchk_schid, 0);
 802 }
 803
 804 static void __init
 805 css_generate_pgid(struct channel_subsystem *css, u32 tod_high)
 806 {
 807         struct cpuid cpu_id;
 808
 809         if (css_general_characteristics.mcss) {
 810                 css->global_pgid.pgid_high.ext_cssid.version = 0x80;
 811                 css->global_pgid.pgid_high.ext_cssid.cssid =
 812                         (css->cssid < 0) ? 0 : css->cssid;
 813         } else {
 814                 css->global_pgid.pgid_high.cpu_addr = stap();
 815         }
 816         get_cpu_id(&cpu_id);
 817         css->global_pgid.cpu_id = cpu_id.ident;
 818         css->global_pgid.cpu_model = cpu_id.machine;
 819         css->global_pgid.tod_high = tod_high;
 820 }
 821
 822 static void channel_subsystem_release(struct device *dev)
 823 {
 824         struct channel_subsystem *css = to_css(dev);
 825
 826         mutex_destroy(&css->mutex);
 827         kfree(css);
 828 }
 829
 830 static ssize_t real_cssid_show(struct device *dev, struct device_attribute *a,
 831                                char *buf)
 832 {
 833         struct channel_subsystem *css = to_css(dev);
 834
 835         if (css->cssid < 0)
 836                 return -EINVAL;
 837
 838         return sprintf(buf, "%x\n", css->cssid);
 839 }
 840 static DEVICE_ATTR_RO(real_cssid);
 841
 842 static ssize_t cm_enable_show(struct device *dev, struct device_attribute *a,
 843                               char *buf)
 844 {
 845         struct channel_subsystem *css = to_css(dev);
 846         int ret;
 847
 848         mutex_lock(&css->mutex);
 849         ret = sprintf(buf, "%x\n", css->cm_enabled);
 850         mutex_unlock(&css->mutex);
 851         return ret;
 852 }
 853
 854 static ssize_t cm_enable_store(struct device *dev, struct device_attribute *a,
 855                                const char *buf, size_t count)
 856 {
 857         struct channel_subsystem *css = to_css(dev);
 858         unsigned long val;
 859         int ret;
 860
 861         ret = kstrtoul(buf, 16, &val);
 862         if (ret)
 863                 return ret;
 864         mutex_lock(&css->mutex);
 865         switch (val) {
 866         case 0:
 867                 ret = css->cm_enabled ? chsc_secm(css, 0) : 0;
 868                 break;
 869         case 1:
 870                 ret = css->cm_enabled ? 0 : chsc_secm(css, 1);
 871                 break;
 872         default:
 873                 ret = -EINVAL;
 874         }
 875         mutex_unlock(&css->mutex);
 876         return ret < 0 ? ret : count;
 877 }
 878 static DEVICE_ATTR_RW(cm_enable);
 879
 880 static umode_t cm_enable_mode(struct kobject *kobj, struct attribute *attr,
 881                               int index)
 882 {
 883         return css_chsc_characteristics.secm ? attr->mode : 0;
 884 }
 885
 886 static struct attribute *cssdev_attrs[] = {
 887         &dev_attr_real_cssid.attr,
 888         NULL,
 889 };
 890
 891 static struct attribute_group cssdev_attr_group = {
 892         .attrs = cssdev_attrs,
 893 };
 894
 895 static struct attribute *cssdev_cm_attrs[] = {
 896         &dev_attr_cm_enable.attr,
 897         NULL,
 898 };
 899
 900 static struct attribute_group cssdev_cm_attr_group = {
 901         .attrs = cssdev_cm_attrs,
 902         .is_visible = cm_enable_mode,
 903 };
 904
 905 static const struct attribute_group *cssdev_attr_groups[] = {
 906         &cssdev_attr_group,
 907         &cssdev_cm_attr_group,
 908         NULL,
 909 };
 910
 911 static int __init setup_css(int nr)
 912 {
 913         struct channel_subsystem *css;
 914         int ret;
 915
 916         css = kzalloc(sizeof(*css), GFP_KERNEL);
 917         if (!css)
 918                 return -ENOMEM;
 919
 920         channel_subsystems[nr] = css;
 921         dev_set_name(&css->device, "css%x", nr);
 922         css->device.groups = cssdev_attr_groups;
 923         css->device.release = channel_subsystem_release;
 924
 925         mutex_init(&css->mutex);
 926         css->cssid = chsc_get_cssid(nr);
 927         css_generate_pgid(css, (u32) (get_tod_clock() >> 32));
 928
 929         ret = device_register(&css->device);
 930         if (ret) {
 931                 put_device(&css->device);
 932                 goto out_err;
 933         }
 934
 935         css->pseudo_subchannel = kzalloc(sizeof(*css->pseudo_subchannel),
 936                                          GFP_KERNEL);
 937         if (!css->pseudo_subchannel) {
 938                 device_unregister(&css->device);
 939                 ret = -ENOMEM;
 940                 goto out_err;
 941         }
 942
 943         css->pseudo_subchannel->dev.parent = &css->device;
 944         css->pseudo_subchannel->dev.release = css_subchannel_release;
 945         mutex_init(&css->pseudo_subchannel->reg_mutex);
 946         ret = css_sch_create_locks(css->pseudo_subchannel);
 947         if (ret) {
 948                 kfree(css->pseudo_subchannel);
 949                 device_unregister(&css->device);
 950                 goto out_err;
 951         }
 952
 953         dev_set_name(&css->pseudo_subchannel->dev, "defunct");
 954         ret = device_register(&css->pseudo_subchannel->dev);
 955         if (ret) {
 956                 put_device(&css->pseudo_subchannel->dev);
 957                 device_unregister(&css->device);
 958                 goto out_err;
 959         }
 960
 961         return ret;
 962 out_err:
 963         channel_subsystems[nr] = NULL;
 964         return ret;
 965 }
 966
 967 static int css_reboot_event(struct notifier_block *this,
 968                             unsigned long event,
 969                             void *ptr)
 970 {
 971         struct channel_subsystem *css;
 972         int ret;
 973
 974         ret = NOTIFY_DONE;
 975         for_each_css(css) {
 976                 mutex_lock(&css->mutex);
 977                 if (css->cm_enabled)
 978                         if (chsc_secm(css, 0))
 979                                 ret = NOTIFY_BAD;
 980                 mutex_unlock(&css->mutex);
 981         }
 982
 983         return ret;
 984 }
 985
 986 static struct notifier_block css_reboot_notifier = {
 987         .notifier_call = css_reboot_event,
 988 };
 989
 990 /*
 991  * Since the css devices are neither on a bus nor have a class
 992  * nor have a special device type, we cannot stop/restart channel
 993  * path measurements via the normal suspend/resume callbacks, but have
 994  * to use notifiers.
 995  */
 996 static int css_power_event(struct notifier_block *this, unsigned long event,
 997                            void *ptr)
 998 {
 999         struct channel_subsystem *css;
1000         int ret;
1001
1002         switch (event) {
1003         case PM_HIBERNATION_PREPARE:
1004         case PM_SUSPEND_PREPARE:
1005                 ret = NOTIFY_DONE;
1006                 for_each_css(css) {
1007                         mutex_lock(&css->mutex);
1008                         if (!css->cm_enabled) {
1009                                 mutex_unlock(&css->mutex);
1010                                 continue;
1011                         }
1012                         ret = __chsc_do_secm(css, 0);
1013                         ret = notifier_from_errno(ret);
1014                         mutex_unlock(&css->mutex);
1015                 }
1016                 break;
1017         case PM_POST_HIBERNATION:
1018         case PM_POST_SUSPEND:
1019                 ret = NOTIFY_DONE;
1020                 for_each_css(css) {
1021                         mutex_lock(&css->mutex);
1022                         if (!css->cm_enabled) {
1023                                 mutex_unlock(&css->mutex);
1024                                 continue;
1025                         }
1026                         ret = __chsc_do_secm(css, 1);
1027                         ret = notifier_from_errno(ret);
1028                         mutex_unlock(&css->mutex);
1029                 }
1030                 /* search for subchannels, which appeared during hibernation */
1031                 css_schedule_reprobe();
1032                 break;
1033         default:
1034                 ret = NOTIFY_DONE;
1035         }
1036         return ret;
1037
1038 }
1039 static struct notifier_block css_power_notifier = {
1040         .notifier_call = css_power_event,
1041 };
1042
1043 /*
1044  * Now that the driver core is running, we can setup our channel subsystem.
1045  * The struct subchannel's are created during probing.
1046  */
1047 static int __init css_bus_init(void)
1048 {
1049         int ret, i;
1050
1051         ret = chsc_init();
1052         if (ret)
1053                 return ret;
1054
1055         chsc_determine_css_characteristics();
1056         /* Try to enable MSS. */
1057         ret = chsc_enable_facility(CHSC_SDA_OC_MSS);
1058         if (ret)
1059                 max_ssid = 0;
1060         else /* Success. */
1061                 max_ssid = __MAX_SSID;
1062
1063         ret = slow_subchannel_init();
1064         if (ret)
1065                 goto out;
1066
1067         ret = crw_register_handler(CRW_RSC_SCH, css_process_crw);
1068         if (ret)
1069                 goto out;
1070
1071         if ((ret = bus_register(&css_bus_type)))
1072                 goto out;
1073
1074         /* Setup css structure. */
1075         for (i = 0; i <= MAX_CSS_IDX; i++) {
1076                 ret = setup_css(i);
1077                 if (ret)
1078                         goto out_unregister;
1079         }
1080         ret = register_reboot_notifier(&css_reboot_notifier);
1081         if (ret)
1082                 goto out_unregister;
1083         ret = register_pm_notifier(&css_power_notifier);
1084         if (ret) {
1085                 unregister_reboot_notifier(&css_reboot_notifier);
1086                 goto out_unregister;
1087         }
1088         css_init_done = 1;
1089
1090         /* Enable default isc for I/O subchannels. */
1091         isc_register(IO_SCH_ISC);
1092
1093         return 0;
1094 out_unregister:
1095         while (i-- > 0) {
1096                 struct channel_subsystem *css = channel_subsystems[i];
1097                 device_unregister(&css->pseudo_subchannel->dev);
1098                 device_unregister(&css->device);
1099         }
1100         bus_unregister(&css_bus_type);
1101 out:
1102         crw_unregister_handler(CRW_RSC_SCH);
1103         idset_free(slow_subchannel_set);
1104         chsc_init_cleanup();
1105         pr_alert("The CSS device driver initialization failed with "
1106                  "errno=%d\n", ret);
1107         return ret;
1108 }
1109
1110 static void __init css_bus_cleanup(void)
1111 {
1112         struct channel_subsystem *css;
1113
1114         for_each_css(css) {
1115                 device_unregister(&css->pseudo_subchannel->dev);
1116                 device_unregister(&css->device);
1117         }
1118         bus_unregister(&css_bus_type);
1119         crw_unregister_handler(CRW_RSC_SCH);
1120         idset_free(slow_subchannel_set);
1121         chsc_init_cleanup();
1122         isc_unregister(IO_SCH_ISC);
1123 }
1124
1125 static int __init channel_subsystem_init(void)
1126 {
1127         int ret;
1128
1129         ret = css_bus_init();
1130         if (ret)
1131                 return ret;
1132         cio_work_q = create_singlethread_workqueue("cio");
1133         if (!cio_work_q) {
1134                 ret = -ENOMEM;
1135                 goto out_bus;
1136         }
1137         ret = io_subchannel_init();
1138         if (ret)
1139                 goto out_wq;
1140
1141         /* Register subchannels which are already in use. */
1142         cio_register_early_subchannels();
1143         /* Start initial subchannel evaluation. */
1144         css_schedule_eval_all();
1145
1146         return ret;
1147 out_wq:
1148         destroy_workqueue(cio_work_q);
1149 out_bus:
1150         css_bus_cleanup();
1151         return ret;
1152 }
1153 subsys_initcall(channel_subsystem_init);
1154
1155 static int css_settle(struct device_driver *drv, void *unused)
1156 {
1157         struct css_driver *cssdrv = to_cssdriver(drv);
1158
1159         if (cssdrv->settle)
1160                 return cssdrv->settle();
1161         return 0;
1162 }
1163
1164 int css_complete_work(void)
1165 {
1166         int ret;
1167
1168         /* Wait for the evaluation of subchannels to finish. */
1169         ret = wait_event_interruptible(css_eval_wq,
1170                                        atomic_read(&css_eval_scheduled) == 0);
1171         if (ret)
1172                 return -EINTR;
1173         flush_workqueue(cio_work_q);
1174         /* Wait for the subchannel type specific initialization to finish */
1175         return bus_for_each_drv(&css_bus_type, NULL, NULL, css_settle);
1176 }
1177
1178
1179 /*
1180  * Wait for the initialization of devices to finish, to make sure we are
1181  * done with our setup if the search for the root device starts.
1182  */
1183 static int __init channel_subsystem_init_sync(void)
1184 {
1185         css_complete_work();
1186         return 0;
1187 }
1188 subsys_initcall_sync(channel_subsystem_init_sync);
1189
1190 void channel_subsystem_reinit(void)
1191 {
1192         struct channel_path *chp;
1193         struct chp_id chpid;
1194
1195         chsc_enable_facility(CHSC_SDA_OC_MSS);
1196         chp_id_for_each(&chpid) {
1197                 chp = chpid_to_chp(chpid);
1198                 if (chp)
1199                         chp_update_desc(chp);
1200         }
1201         cmf_reactivate();
1202 }
1203
1204 #ifdef CONFIG_PROC_FS
1205 static ssize_t cio_settle_write(struct file *file, const char __user *buf,
1206                                 size_t count, loff_t *ppos)
1207 {
1208         int ret;
1209
1210         /* Handle pending CRW's. */
1211         crw_wait_for_channel_report();
1212         ret = css_complete_work();
1213
1214         return ret ? ret : count;
1215 }
1216
1217 static const struct file_operations cio_settle_proc_fops = {
1218         .open = nonseekable_open,
1219         .write = cio_settle_write,
1220         .llseek = no_llseek,
1221 };
1222
1223 static int __init cio_settle_init(void)
1224 {
1225         struct proc_dir_entry *entry;
1226
1227         entry = proc_create("cio_settle", S_IWUSR, NULL,
1228                             &cio_settle_proc_fops);
1229         if (!entry)
1230                 return -ENOMEM;
1231         return 0;
1232 }
1233 device_initcall(cio_settle_init);
1234 #endif /*CONFIG_PROC_FS*/
1235
1236 int sch_is_pseudo_sch(struct subchannel *sch)
1237 {
1238         if (!sch->dev.parent)
1239                 return 0;
1240         return sch == to_css(sch->dev.parent)->pseudo_subchannel;
1241 }
1242
1243 static int css_bus_match(struct device *dev, struct device_driver *drv)
1244 {
1245         struct subchannel *sch = to_subchannel(dev);
1246         struct css_driver *driver = to_cssdriver(drv);
1247         struct css_device_id *id;
1248
1249         for (id = driver->subchannel_type; id->match_flags; id++) {
1250                 if (sch->st == id->type)
1251                         return 1;
1252         }
1253
1254         return 0;
1255 }
1256
1257 static int css_probe(struct device *dev)
1258 {
1259         struct subchannel *sch;
1260         int ret;
1261
1262         sch = to_subchannel(dev);
1263         sch->driver = to_cssdriver(dev->driver);
1264         ret = sch->driver->probe ? sch->driver->probe(sch) : 0;
1265         if (ret)
1266                 sch->driver = NULL;
1267         return ret;
1268 }
1269
1270 static int css_remove(struct device *dev)
1271 {
1272         struct subchannel *sch;
1273         int ret;
1274
1275         sch = to_subchannel(dev);
1276         ret = sch->driver->remove ? sch->driver->remove(sch) : 0;
1277         sch->driver = NULL;
1278         return ret;
1279 }
1280
1281 static void css_shutdown(struct device *dev)
1282 {
1283         struct subchannel *sch;
1284
1285         sch = to_subchannel(dev);
1286         if (sch->driver && sch->driver->shutdown)
1287                 sch->driver->shutdown(sch);
1288 }
1289
1290 static int css_uevent(struct device *dev, struct kobj_uevent_env *env)
1291 {
1292         struct subchannel *sch = to_subchannel(dev);
1293         int ret;
1294
1295         ret = add_uevent_var(env, "ST=%01X", sch->st);
1296         if (ret)
1297                 return ret;
1298         ret = add_uevent_var(env, "MODALIAS=css:t%01X", sch->st);
1299         return ret;
1300 }
1301
1302 static int css_pm_prepare(struct device *dev)
1303 {
1304         struct subchannel *sch = to_subchannel(dev);
1305         struct css_driver *drv;
1306
1307         if (mutex_is_locked(&sch->reg_mutex))
1308                 return -EAGAIN;
1309         if (!sch->dev.driver)
1310                 return 0;
1311         drv = to_cssdriver(sch->dev.driver);
1312         /* Notify drivers that they may not register children. */
1313         return drv->prepare ? drv->prepare(sch) : 0;
1314 }
1315
1316 static void css_pm_complete(struct device *dev)
1317 {
1318         struct subchannel *sch = to_subchannel(dev);
1319         struct css_driver *drv;
1320
1321         if (!sch->dev.driver)
1322                 return;
1323         drv = to_cssdriver(sch->dev.driver);
1324         if (drv->complete)
1325                 drv->complete(sch);
1326 }
1327
1328 static int css_pm_freeze(struct device *dev)
1329 {
1330         struct subchannel *sch = to_subchannel(dev);
1331         struct css_driver *drv;
1332
1333         if (!sch->dev.driver)
1334                 return 0;
1335         drv = to_cssdriver(sch->dev.driver);
1336         return drv->freeze ? drv->freeze(sch) : 0;
1337 }
1338
1339 static int css_pm_thaw(struct device *dev)
1340 {
1341         struct subchannel *sch = to_subchannel(dev);
1342         struct css_driver *drv;
1343
1344         if (!sch->dev.driver)
1345                 return 0;
1346         drv = to_cssdriver(sch->dev.driver);
1347         return drv->thaw ? drv->thaw(sch) : 0;
1348 }
1349
1350 static int css_pm_restore(struct device *dev)
1351 {
1352         struct subchannel *sch = to_subchannel(dev);
1353         struct css_driver *drv;
1354
1355         css_update_ssd_info(sch);
1356         if (!sch->dev.driver)
1357                 return 0;
1358         drv = to_cssdriver(sch->dev.driver);
1359         return drv->restore ? drv->restore(sch) : 0;
1360 }
1361
1362 static const struct dev_pm_ops css_pm_ops = {
1363         .prepare = css_pm_prepare,
1364         .complete = css_pm_complete,
1365         .freeze = css_pm_freeze,
1366         .thaw = css_pm_thaw,
1367         .restore = css_pm_restore,
1368 };
1369
1370 static struct bus_type css_bus_type = {
1371         .name     = "css",
1372         .match    = css_bus_match,
1373         .probe    = css_probe,
1374         .remove   = css_remove,
1375         .shutdown = css_shutdown,
1376         .uevent   = css_uevent,
1377         .pm = &css_pm_ops,
1378 };
1379
1380 /**
1381  * css_driver_register - register a css driver
1382  * @cdrv: css driver to register
1383  *
1384  * This is mainly a wrapper around driver_register that sets name
1385  * and bus_type in the embedded struct device_driver correctly.
1386  */
1387 int css_driver_register(struct css_driver *cdrv)
1388 {
1389         cdrv->drv.bus = &css_bus_type;
1390         return driver_register(&cdrv->drv);
1391 }
1392 EXPORT_SYMBOL_GPL(css_driver_register);
1393
1394 /**
1395  * css_driver_unregister - unregister a css driver
1396  * @cdrv: css driver to unregister
1397  *
1398  * This is a wrapper around driver_unregister.
1399  */
1400 void css_driver_unregister(struct css_driver *cdrv)
1401 {
1402         driver_unregister(&cdrv->drv);
1403 }
1404 EXPORT_SYMBOL_GPL(css_driver_unregister);