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 struct attribute *io_subchannel_type_attrs[] = {
 368         &dev_attr_chpids.attr,
 369         &dev_attr_pimpampom.attr,
 370         NULL,
 371 };
 372 ATTRIBUTE_GROUPS(io_subchannel_type);
 373
 374 static const struct device_type io_subchannel_type = {
 375         .groups = io_subchannel_type_groups,
 376 };
 377
 378 int css_register_subchannel(struct subchannel *sch)
 379 {
 380         int ret;
 381
 382         /* Initialize the subchannel structure */
 383         sch->dev.parent = &channel_subsystems[0]->device;
 384         sch->dev.bus = &css_bus_type;
 385         sch->dev.groups = default_subch_attr_groups;
 386
 387         if (sch->st == SUBCHANNEL_TYPE_IO)
 388                 sch->dev.type = &io_subchannel_type;
 389
 390         /*
 391          * We don't want to generate uevents for I/O subchannels that don't
 392          * have a working ccw device behind them since they will be
 393          * unregistered before they can be used anyway, so we delay the add
 394          * uevent until after device recognition was successful.
 395          * Note that we suppress the uevent for all subchannel types;
 396          * the subchannel driver can decide itself when it wants to inform
 397          * userspace of its existence.
 398          */
 399         dev_set_uevent_suppress(&sch->dev, 1);
 400         css_update_ssd_info(sch);
 401         /* make it known to the system */
 402         ret = css_sch_device_register(sch);
 403         if (ret) {
 404                 CIO_MSG_EVENT(0, "Could not register sch 0.%x.%04x: %d\n",
 405                               sch->schid.ssid, sch->schid.sch_no, ret);
 406                 return ret;
 407         }
 408         if (!sch->driver) {
 409                 /*
 410                  * No driver matched. Generate the uevent now so that
 411                  * a fitting driver module may be loaded based on the
 412                  * modalias.
 413                  */
 414                 dev_set_uevent_suppress(&sch->dev, 0);
 415                 kobject_uevent(&sch->dev.kobj, KOBJ_ADD);
 416         }
 417         return ret;
 418 }
 419
 420 static int css_probe_device(struct subchannel_id schid, struct schib *schib)
 421 {
 422         struct subchannel *sch;
 423         int ret;
 424
 425         sch = css_alloc_subchannel(schid, schib);
 426         if (IS_ERR(sch))
 427                 return PTR_ERR(sch);
 428
 429         ret = css_register_subchannel(sch);
 430         if (ret)
 431                 put_device(&sch->dev);
 432
 433         return ret;
 434 }
 435
 436 static int
 437 check_subchannel(struct device * dev, void * data)
 438 {
 439         struct subchannel *sch;
 440         struct subchannel_id *schid = data;
 441
 442         sch = to_subchannel(dev);
 443         return schid_equal(&sch->schid, schid);
 444 }
 445
 446 struct subchannel *
 447 get_subchannel_by_schid(struct subchannel_id schid)
 448 {
 449         struct device *dev;
 450
 451         dev = bus_find_device(&css_bus_type, NULL,
 452                               &schid, check_subchannel);
 453
 454         return dev ? to_subchannel(dev) : NULL;
 455 }
 456
 457 /**
 458  * css_sch_is_valid() - check if a subchannel is valid
 459  * @schib: subchannel information block for the subchannel
 460  */
 461 int css_sch_is_valid(struct schib *schib)
 462 {
 463         if ((schib->pmcw.st == SUBCHANNEL_TYPE_IO) && !schib->pmcw.dnv)
 464                 return 0;
 465         if ((schib->pmcw.st == SUBCHANNEL_TYPE_MSG) && !schib->pmcw.w)
 466                 return 0;
 467         return 1;
 468 }
 469 EXPORT_SYMBOL_GPL(css_sch_is_valid);
 470
 471 static int css_evaluate_new_subchannel(struct subchannel_id schid, int slow)
 472 {
 473         struct schib schib;
 474         int ccode;
 475
 476         if (!slow) {
 477                 /* Will be done on the slow path. */
 478                 return -EAGAIN;
 479         }
 480         /*
 481          * The first subchannel that is not-operational (ccode==3)
 482          * indicates that there aren't any more devices available.
 483          * If stsch gets an exception, it means the current subchannel set
 484          * is not valid.
 485          */
 486         ccode = stsch(schid, &schib);
 487         if (ccode)
 488                 return (ccode == 3) ? -ENXIO : ccode;
 489
 490         return css_probe_device(schid, &schib);
 491 }
 492
 493 static int css_evaluate_known_subchannel(struct subchannel *sch, int slow)
 494 {
 495         int ret = 0;
 496
 497         if (sch->driver) {
 498                 if (sch->driver->sch_event)
 499                         ret = sch->driver->sch_event(sch, slow);
 500                 else
 501                         dev_dbg(&sch->dev,
 502                                 "Got subchannel machine check but "
 503                                 "no sch_event handler provided.\n");
 504         }
 505         if (ret != 0 && ret != -EAGAIN) {
 506                 CIO_MSG_EVENT(2, "eval: sch 0.%x.%04x, rc=%d\n",
 507                               sch->schid.ssid, sch->schid.sch_no, ret);
 508         }
 509         return ret;
 510 }
 511
 512 static void css_evaluate_subchannel(struct subchannel_id schid, int slow)
 513 {
 514         struct subchannel *sch;
 515         int ret;
 516
 517         sch = get_subchannel_by_schid(schid);
 518         if (sch) {
 519                 ret = css_evaluate_known_subchannel(sch, slow);
 520                 put_device(&sch->dev);
 521         } else
 522                 ret = css_evaluate_new_subchannel(schid, slow);
 523         if (ret == -EAGAIN)
 524                 css_schedule_eval(schid);
 525 }
 526
 527 /**
 528  * css_sched_sch_todo - schedule a subchannel operation
 529  * @sch: subchannel
 530  * @todo: todo
 531  *
 532  * Schedule the operation identified by @todo to be performed on the slow path
 533  * workqueue. Do nothing if another operation with higher priority is already
 534  * scheduled. Needs to be called with subchannel lock held.
 535  */
 536 void css_sched_sch_todo(struct subchannel *sch, enum sch_todo todo)
 537 {
 538         CIO_MSG_EVENT(4, "sch_todo: sched sch=0.%x.%04x todo=%d\n",
 539                       sch->schid.ssid, sch->schid.sch_no, todo);
 540         if (sch->todo >= todo)
 541                 return;
 542         /* Get workqueue ref. */
 543         if (!get_device(&sch->dev))
 544                 return;
 545         sch->todo = todo;
 546         if (!queue_work(cio_work_q, &sch->todo_work)) {
 547                 /* Already queued, release workqueue ref. */
 548                 put_device(&sch->dev);
 549         }
 550 }
 551 EXPORT_SYMBOL_GPL(css_sched_sch_todo);
 552
 553 static void css_sch_todo(struct work_struct *work)
 554 {
 555         struct subchannel *sch;
 556         enum sch_todo todo;
 557         int ret;
 558
 559         sch = container_of(work, struct subchannel, todo_work);
 560         /* Find out todo. */
 561         spin_lock_irq(sch->lock);
 562         todo = sch->todo;
 563         CIO_MSG_EVENT(4, "sch_todo: sch=0.%x.%04x, todo=%d\n", sch->schid.ssid,
 564                       sch->schid.sch_no, todo);
 565         sch->todo = SCH_TODO_NOTHING;
 566         spin_unlock_irq(sch->lock);
 567         /* Perform todo. */
 568         switch (todo) {
 569         case SCH_TODO_NOTHING:
 570                 break;
 571         case SCH_TODO_EVAL:
 572                 ret = css_evaluate_known_subchannel(sch, 1);
 573                 if (ret == -EAGAIN) {
 574                         spin_lock_irq(sch->lock);
 575                         css_sched_sch_todo(sch, todo);
 576                         spin_unlock_irq(sch->lock);
 577                 }
 578                 break;
 579         case SCH_TODO_UNREG:
 580                 css_sch_device_unregister(sch);
 581                 break;
 582         }
 583         /* Release workqueue ref. */
 584         put_device(&sch->dev);
 585 }
 586
 587 static struct idset *slow_subchannel_set;
 588 static spinlock_t slow_subchannel_lock;
 589 static wait_queue_head_t css_eval_wq;
 590 static atomic_t css_eval_scheduled;
 591
 592 static int __init slow_subchannel_init(void)
 593 {
 594         spin_lock_init(&slow_subchannel_lock);
 595         atomic_set(&css_eval_scheduled, 0);
 596         init_waitqueue_head(&css_eval_wq);
 597         slow_subchannel_set = idset_sch_new();
 598         if (!slow_subchannel_set) {
 599                 CIO_MSG_EVENT(0, "could not allocate slow subchannel set\n");
 600                 return -ENOMEM;
 601         }
 602         return 0;
 603 }
 604
 605 static int slow_eval_known_fn(struct subchannel *sch, void *data)
 606 {
 607         int eval;
 608         int rc;
 609
 610         spin_lock_irq(&slow_subchannel_lock);
 611         eval = idset_sch_contains(slow_subchannel_set, sch->schid);
 612         idset_sch_del(slow_subchannel_set, sch->schid);
 613         spin_unlock_irq(&slow_subchannel_lock);
 614         if (eval) {
 615                 rc = css_evaluate_known_subchannel(sch, 1);
 616                 if (rc == -EAGAIN)
 617                         css_schedule_eval(sch->schid);
 618         }
 619         return 0;
 620 }
 621
 622 static int slow_eval_unknown_fn(struct subchannel_id schid, void *data)
 623 {
 624         int eval;
 625         int rc = 0;
 626
 627         spin_lock_irq(&slow_subchannel_lock);
 628         eval = idset_sch_contains(slow_subchannel_set, schid);
 629         idset_sch_del(slow_subchannel_set, schid);
 630         spin_unlock_irq(&slow_subchannel_lock);
 631         if (eval) {
 632                 rc = css_evaluate_new_subchannel(schid, 1);
 633                 switch (rc) {
 634                 case -EAGAIN:
 635                         css_schedule_eval(schid);
 636                         rc = 0;
 637                         break;
 638                 case -ENXIO:
 639                 case -ENOMEM:
 640                 case -EIO:
 641                         /* These should abort looping */
 642                         spin_lock_irq(&slow_subchannel_lock);
 643                         idset_sch_del_subseq(slow_subchannel_set, schid);
 644                         spin_unlock_irq(&slow_subchannel_lock);
 645                         break;
 646                 default:
 647                         rc = 0;
 648                 }
 649                 /* Allow scheduling here since the containing loop might
 650                  * take a while.  */
 651                 cond_resched();
 652         }
 653         return rc;
 654 }
 655
 656 static void css_slow_path_func(struct work_struct *unused)
 657 {
 658         unsigned long flags;
 659
 660         CIO_TRACE_EVENT(4, "slowpath");
 661         for_each_subchannel_staged(slow_eval_known_fn, slow_eval_unknown_fn,
 662                                    NULL);
 663         spin_lock_irqsave(&slow_subchannel_lock, flags);
 664         if (idset_is_empty(slow_subchannel_set)) {
 665                 atomic_set(&css_eval_scheduled, 0);
 666                 wake_up(&css_eval_wq);
 667         }
 668         spin_unlock_irqrestore(&slow_subchannel_lock, flags);
 669 }
 670
 671 static DECLARE_DELAYED_WORK(slow_path_work, css_slow_path_func);
 672 struct workqueue_struct *cio_work_q;
 673
 674 void css_schedule_eval(struct subchannel_id schid)
 675 {
 676         unsigned long flags;
 677
 678         spin_lock_irqsave(&slow_subchannel_lock, flags);
 679         idset_sch_add(slow_subchannel_set, schid);
 680         atomic_set(&css_eval_scheduled, 1);
 681         queue_delayed_work(cio_work_q, &slow_path_work, 0);
 682         spin_unlock_irqrestore(&slow_subchannel_lock, flags);
 683 }
 684
 685 void css_schedule_eval_all(void)
 686 {
 687         unsigned long flags;
 688
 689         spin_lock_irqsave(&slow_subchannel_lock, flags);
 690         idset_fill(slow_subchannel_set);
 691         atomic_set(&css_eval_scheduled, 1);
 692         queue_delayed_work(cio_work_q, &slow_path_work, 0);
 693         spin_unlock_irqrestore(&slow_subchannel_lock, flags);
 694 }
 695
 696 static int __unset_registered(struct device *dev, void *data)
 697 {
 698         struct idset *set = data;
 699         struct subchannel *sch = to_subchannel(dev);
 700
 701         idset_sch_del(set, sch->schid);
 702         return 0;
 703 }
 704
 705 void css_schedule_eval_all_unreg(unsigned long delay)
 706 {
 707         unsigned long flags;
 708         struct idset *unreg_set;
 709
 710         /* Find unregistered subchannels. */
 711         unreg_set = idset_sch_new();
 712         if (!unreg_set) {
 713                 /* Fallback. */
 714                 css_schedule_eval_all();
 715                 return;
 716         }
 717         idset_fill(unreg_set);
 718         bus_for_each_dev(&css_bus_type, NULL, unreg_set, __unset_registered);
 719         /* Apply to slow_subchannel_set. */
 720         spin_lock_irqsave(&slow_subchannel_lock, flags);
 721         idset_add_set(slow_subchannel_set, unreg_set);
 722         atomic_set(&css_eval_scheduled, 1);
 723         queue_delayed_work(cio_work_q, &slow_path_work, delay);
 724         spin_unlock_irqrestore(&slow_subchannel_lock, flags);
 725         idset_free(unreg_set);
 726 }
 727
 728 void css_wait_for_slow_path(void)
 729 {
 730         flush_workqueue(cio_work_q);
 731 }
 732
 733 /* Schedule reprobing of all unregistered subchannels. */
 734 void css_schedule_reprobe(void)
 735 {
 736         /* Schedule with a delay to allow merging of subsequent calls. */
 737         css_schedule_eval_all_unreg(1 * HZ);
 738 }
 739 EXPORT_SYMBOL_GPL(css_schedule_reprobe);
 740
 741 /*
 742  * Called from the machine check handler for subchannel report words.
 743  */
 744 static void css_process_crw(struct crw *crw0, struct crw *crw1, int overflow)
 745 {
 746         struct subchannel_id mchk_schid;
 747         struct subchannel *sch;
 748
 749         if (overflow) {
 750                 css_schedule_eval_all();
 751                 return;
 752         }
 753         CIO_CRW_EVENT(2, "CRW0 reports slct=%d, oflw=%d, "
 754                       "chn=%d, rsc=%X, anc=%d, erc=%X, rsid=%X\n",
 755                       crw0->slct, crw0->oflw, crw0->chn, crw0->rsc, crw0->anc,
 756                       crw0->erc, crw0->rsid);
 757         if (crw1)
 758                 CIO_CRW_EVENT(2, "CRW1 reports slct=%d, oflw=%d, "
 759                               "chn=%d, rsc=%X, anc=%d, erc=%X, rsid=%X\n",
 760                               crw1->slct, crw1->oflw, crw1->chn, crw1->rsc,
 761                               crw1->anc, crw1->erc, crw1->rsid);
 762         init_subchannel_id(&mchk_schid);
 763         mchk_schid.sch_no = crw0->rsid;
 764         if (crw1)
 765                 mchk_schid.ssid = (crw1->rsid >> 4) & 3;
 766
 767         if (crw0->erc == CRW_ERC_PMOD) {
 768                 sch = get_subchannel_by_schid(mchk_schid);
 769                 if (sch) {
 770                         css_update_ssd_info(sch);
 771                         put_device(&sch->dev);
 772                 }
 773         }
 774         /*
 775          * Since we are always presented with IPI in the CRW, we have to
 776          * use stsch() to find out if the subchannel in question has come
 777          * or gone.
 778          */
 779         css_evaluate_subchannel(mchk_schid, 0);
 780 }
 781
 782 static void __init
 783 css_generate_pgid(struct channel_subsystem *css, u32 tod_high)
 784 {
 785         struct cpuid cpu_id;
 786
 787         if (css_general_characteristics.mcss) {
 788                 css->global_pgid.pgid_high.ext_cssid.version = 0x80;
 789                 css->global_pgid.pgid_high.ext_cssid.cssid =
 790                         (css->cssid < 0) ? 0 : css->cssid;
 791         } else {
 792                 css->global_pgid.pgid_high.cpu_addr = stap();
 793         }
 794         get_cpu_id(&cpu_id);
 795         css->global_pgid.cpu_id = cpu_id.ident;
 796         css->global_pgid.cpu_model = cpu_id.machine;
 797         css->global_pgid.tod_high = tod_high;
 798 }
 799
 800 static void channel_subsystem_release(struct device *dev)
 801 {
 802         struct channel_subsystem *css = to_css(dev);
 803
 804         mutex_destroy(&css->mutex);
 805         kfree(css);
 806 }
 807
 808 static ssize_t real_cssid_show(struct device *dev, struct device_attribute *a,
 809                                char *buf)
 810 {
 811         struct channel_subsystem *css = to_css(dev);
 812
 813         if (css->cssid < 0)
 814                 return -EINVAL;
 815
 816         return sprintf(buf, "%x\n", css->cssid);
 817 }
 818 static DEVICE_ATTR_RO(real_cssid);
 819
 820 static ssize_t cm_enable_show(struct device *dev, struct device_attribute *a,
 821                               char *buf)
 822 {
 823         struct channel_subsystem *css = to_css(dev);
 824         int ret;
 825
 826         mutex_lock(&css->mutex);
 827         ret = sprintf(buf, "%x\n", css->cm_enabled);
 828         mutex_unlock(&css->mutex);
 829         return ret;
 830 }
 831
 832 static ssize_t cm_enable_store(struct device *dev, struct device_attribute *a,
 833                                const char *buf, size_t count)
 834 {
 835         struct channel_subsystem *css = to_css(dev);
 836         unsigned long val;
 837         int ret;
 838
 839         ret = kstrtoul(buf, 16, &val);
 840         if (ret)
 841                 return ret;
 842         mutex_lock(&css->mutex);
 843         switch (val) {
 844         case 0:
 845                 ret = css->cm_enabled ? chsc_secm(css, 0) : 0;
 846                 break;
 847         case 1:
 848                 ret = css->cm_enabled ? 0 : chsc_secm(css, 1);
 849                 break;
 850         default:
 851                 ret = -EINVAL;
 852         }
 853         mutex_unlock(&css->mutex);
 854         return ret < 0 ? ret : count;
 855 }
 856 static DEVICE_ATTR_RW(cm_enable);
 857
 858 static umode_t cm_enable_mode(struct kobject *kobj, struct attribute *attr,
 859                               int index)
 860 {
 861         return css_chsc_characteristics.secm ? attr->mode : 0;
 862 }
 863
 864 static struct attribute *cssdev_attrs[] = {
 865         &dev_attr_real_cssid.attr,
 866         NULL,
 867 };
 868
 869 static struct attribute_group cssdev_attr_group = {
 870         .attrs = cssdev_attrs,
 871 };
 872
 873 static struct attribute *cssdev_cm_attrs[] = {
 874         &dev_attr_cm_enable.attr,
 875         NULL,
 876 };
 877
 878 static struct attribute_group cssdev_cm_attr_group = {
 879         .attrs = cssdev_cm_attrs,
 880         .is_visible = cm_enable_mode,
 881 };
 882
 883 static const struct attribute_group *cssdev_attr_groups[] = {
 884         &cssdev_attr_group,
 885         &cssdev_cm_attr_group,
 886         NULL,
 887 };
 888
 889 static int __init setup_css(int nr)
 890 {
 891         struct channel_subsystem *css;
 892         int ret;
 893
 894         css = kzalloc(sizeof(*css), GFP_KERNEL);
 895         if (!css)
 896                 return -ENOMEM;
 897
 898         channel_subsystems[nr] = css;
 899         dev_set_name(&css->device, "css%x", nr);
 900         css->device.groups = cssdev_attr_groups;
 901         css->device.release = channel_subsystem_release;
 902
 903         mutex_init(&css->mutex);
 904         css->cssid = chsc_get_cssid(nr);
 905         css_generate_pgid(css, (u32) (get_tod_clock() >> 32));
 906
 907         ret = device_register(&css->device);
 908         if (ret) {
 909                 put_device(&css->device);
 910                 goto out_err;
 911         }
 912
 913         css->pseudo_subchannel = kzalloc(sizeof(*css->pseudo_subchannel),
 914                                          GFP_KERNEL);
 915         if (!css->pseudo_subchannel) {
 916                 device_unregister(&css->device);
 917                 ret = -ENOMEM;
 918                 goto out_err;
 919         }
 920
 921         css->pseudo_subchannel->dev.parent = &css->device;
 922         css->pseudo_subchannel->dev.release = css_subchannel_release;
 923         mutex_init(&css->pseudo_subchannel->reg_mutex);
 924         ret = css_sch_create_locks(css->pseudo_subchannel);
 925         if (ret) {
 926                 kfree(css->pseudo_subchannel);
 927                 device_unregister(&css->device);
 928                 goto out_err;
 929         }
 930
 931         dev_set_name(&css->pseudo_subchannel->dev, "defunct");
 932         ret = device_register(&css->pseudo_subchannel->dev);
 933         if (ret) {
 934                 put_device(&css->pseudo_subchannel->dev);
 935                 device_unregister(&css->device);
 936                 goto out_err;
 937         }
 938
 939         return ret;
 940 out_err:
 941         channel_subsystems[nr] = NULL;
 942         return ret;
 943 }
 944
 945 static int css_reboot_event(struct notifier_block *this,
 946                             unsigned long event,
 947                             void *ptr)
 948 {
 949         struct channel_subsystem *css;
 950         int ret;
 951
 952         ret = NOTIFY_DONE;
 953         for_each_css(css) {
 954                 mutex_lock(&css->mutex);
 955                 if (css->cm_enabled)
 956                         if (chsc_secm(css, 0))
 957                                 ret = NOTIFY_BAD;
 958                 mutex_unlock(&css->mutex);
 959         }
 960
 961         return ret;
 962 }
 963
 964 static struct notifier_block css_reboot_notifier = {
 965         .notifier_call = css_reboot_event,
 966 };
 967
 968 /*
 969  * Since the css devices are neither on a bus nor have a class
 970  * nor have a special device type, we cannot stop/restart channel
 971  * path measurements via the normal suspend/resume callbacks, but have
 972  * to use notifiers.
 973  */
 974 static int css_power_event(struct notifier_block *this, unsigned long event,
 975                            void *ptr)
 976 {
 977         struct channel_subsystem *css;
 978         int ret;
 979
 980         switch (event) {
 981         case PM_HIBERNATION_PREPARE:
 982         case PM_SUSPEND_PREPARE:
 983                 ret = NOTIFY_DONE;
 984                 for_each_css(css) {
 985                         mutex_lock(&css->mutex);
 986                         if (!css->cm_enabled) {
 987                                 mutex_unlock(&css->mutex);
 988                                 continue;
 989                         }
 990                         ret = __chsc_do_secm(css, 0);
 991                         ret = notifier_from_errno(ret);
 992                         mutex_unlock(&css->mutex);
 993                 }
 994                 break;
 995         case PM_POST_HIBERNATION:
 996         case PM_POST_SUSPEND:
 997                 ret = NOTIFY_DONE;
 998                 for_each_css(css) {
 999                         mutex_lock(&css->mutex);
1000                         if (!css->cm_enabled) {
1001                                 mutex_unlock(&css->mutex);
1002                                 continue;
1003                         }
1004                         ret = __chsc_do_secm(css, 1);
1005                         ret = notifier_from_errno(ret);
1006                         mutex_unlock(&css->mutex);
1007                 }
1008                 /* search for subchannels, which appeared during hibernation */
1009                 css_schedule_reprobe();
1010                 break;
1011         default:
1012                 ret = NOTIFY_DONE;
1013         }
1014         return ret;
1015
1016 }
1017 static struct notifier_block css_power_notifier = {
1018         .notifier_call = css_power_event,
1019 };
1020
1021 /*
1022  * Now that the driver core is running, we can setup our channel subsystem.
1023  * The struct subchannel's are created during probing.
1024  */
1025 static int __init css_bus_init(void)
1026 {
1027         int ret, i;
1028
1029         ret = chsc_init();
1030         if (ret)
1031                 return ret;
1032
1033         chsc_determine_css_characteristics();
1034         /* Try to enable MSS. */
1035         ret = chsc_enable_facility(CHSC_SDA_OC_MSS);
1036         if (ret)
1037                 max_ssid = 0;
1038         else /* Success. */
1039                 max_ssid = __MAX_SSID;
1040
1041         ret = slow_subchannel_init();
1042         if (ret)
1043                 goto out;
1044
1045         ret = crw_register_handler(CRW_RSC_SCH, css_process_crw);
1046         if (ret)
1047                 goto out;
1048
1049         if ((ret = bus_register(&css_bus_type)))
1050                 goto out;
1051
1052         /* Setup css structure. */
1053         for (i = 0; i <= MAX_CSS_IDX; i++) {
1054                 ret = setup_css(i);
1055                 if (ret)
1056                         goto out_unregister;
1057         }
1058         ret = register_reboot_notifier(&css_reboot_notifier);
1059         if (ret)
1060                 goto out_unregister;
1061         ret = register_pm_notifier(&css_power_notifier);
1062         if (ret) {
1063                 unregister_reboot_notifier(&css_reboot_notifier);
1064                 goto out_unregister;
1065         }
1066         css_init_done = 1;
1067
1068         /* Enable default isc for I/O subchannels. */
1069         isc_register(IO_SCH_ISC);
1070
1071         return 0;
1072 out_unregister:
1073         while (i-- > 0) {
1074                 struct channel_subsystem *css = channel_subsystems[i];
1075                 device_unregister(&css->pseudo_subchannel->dev);
1076                 device_unregister(&css->device);
1077         }
1078         bus_unregister(&css_bus_type);
1079 out:
1080         crw_unregister_handler(CRW_RSC_SCH);
1081         idset_free(slow_subchannel_set);
1082         chsc_init_cleanup();
1083         pr_alert("The CSS device driver initialization failed with "
1084                  "errno=%d\n", ret);
1085         return ret;
1086 }
1087
1088 static void __init css_bus_cleanup(void)
1089 {
1090         struct channel_subsystem *css;
1091
1092         for_each_css(css) {
1093                 device_unregister(&css->pseudo_subchannel->dev);
1094                 device_unregister(&css->device);
1095         }
1096         bus_unregister(&css_bus_type);
1097         crw_unregister_handler(CRW_RSC_SCH);
1098         idset_free(slow_subchannel_set);
1099         chsc_init_cleanup();
1100         isc_unregister(IO_SCH_ISC);
1101 }
1102
1103 static int __init channel_subsystem_init(void)
1104 {
1105         int ret;
1106
1107         ret = css_bus_init();
1108         if (ret)
1109                 return ret;
1110         cio_work_q = create_singlethread_workqueue("cio");
1111         if (!cio_work_q) {
1112                 ret = -ENOMEM;
1113                 goto out_bus;
1114         }
1115         ret = io_subchannel_init();
1116         if (ret)
1117                 goto out_wq;
1118
1119         /* Register subchannels which are already in use. */
1120         cio_register_early_subchannels();
1121         /* Start initial subchannel evaluation. */
1122         css_schedule_eval_all();
1123
1124         return ret;
1125 out_wq:
1126         destroy_workqueue(cio_work_q);
1127 out_bus:
1128         css_bus_cleanup();
1129         return ret;
1130 }
1131 subsys_initcall(channel_subsystem_init);
1132
1133 static int css_settle(struct device_driver *drv, void *unused)
1134 {
1135         struct css_driver *cssdrv = to_cssdriver(drv);
1136
1137         if (cssdrv->settle)
1138                 return cssdrv->settle();
1139         return 0;
1140 }
1141
1142 int css_complete_work(void)
1143 {
1144         int ret;
1145
1146         /* Wait for the evaluation of subchannels to finish. */
1147         ret = wait_event_interruptible(css_eval_wq,
1148                                        atomic_read(&css_eval_scheduled) == 0);
1149         if (ret)
1150                 return -EINTR;
1151         flush_workqueue(cio_work_q);
1152         /* Wait for the subchannel type specific initialization to finish */
1153         return bus_for_each_drv(&css_bus_type, NULL, NULL, css_settle);
1154 }
1155
1156
1157 /*
1158  * Wait for the initialization of devices to finish, to make sure we are
1159  * done with our setup if the search for the root device starts.
1160  */
1161 static int __init channel_subsystem_init_sync(void)
1162 {
1163         css_complete_work();
1164         return 0;
1165 }
1166 subsys_initcall_sync(channel_subsystem_init_sync);
1167
1168 void channel_subsystem_reinit(void)
1169 {
1170         struct channel_path *chp;
1171         struct chp_id chpid;
1172
1173         chsc_enable_facility(CHSC_SDA_OC_MSS);
1174         chp_id_for_each(&chpid) {
1175                 chp = chpid_to_chp(chpid);
1176                 if (chp)
1177                         chp_update_desc(chp);
1178         }
1179         cmf_reactivate();
1180 }
1181
1182 #ifdef CONFIG_PROC_FS
1183 static ssize_t cio_settle_write(struct file *file, const char __user *buf,
1184                                 size_t count, loff_t *ppos)
1185 {
1186         int ret;
1187
1188         /* Handle pending CRW's. */
1189         crw_wait_for_channel_report();
1190         ret = css_complete_work();
1191
1192         return ret ? ret : count;
1193 }
1194
1195 static const struct file_operations cio_settle_proc_fops = {
1196         .open = nonseekable_open,
1197         .write = cio_settle_write,
1198         .llseek = no_llseek,
1199 };
1200
1201 static int __init cio_settle_init(void)
1202 {
1203         struct proc_dir_entry *entry;
1204
1205         entry = proc_create("cio_settle", S_IWUSR, NULL,
1206                             &cio_settle_proc_fops);
1207         if (!entry)
1208                 return -ENOMEM;
1209         return 0;
1210 }
1211 device_initcall(cio_settle_init);
1212 #endif /*CONFIG_PROC_FS*/
1213
1214 int sch_is_pseudo_sch(struct subchannel *sch)
1215 {
1216         return sch == to_css(sch->dev.parent)->pseudo_subchannel;
1217 }
1218
1219 static int css_bus_match(struct device *dev, struct device_driver *drv)
1220 {
1221         struct subchannel *sch = to_subchannel(dev);
1222         struct css_driver *driver = to_cssdriver(drv);
1223         struct css_device_id *id;
1224
1225         for (id = driver->subchannel_type; id->match_flags; id++) {
1226                 if (sch->st == id->type)
1227                         return 1;
1228         }
1229
1230         return 0;
1231 }
1232
1233 static int css_probe(struct device *dev)
1234 {
1235         struct subchannel *sch;
1236         int ret;
1237
1238         sch = to_subchannel(dev);
1239         sch->driver = to_cssdriver(dev->driver);
1240         ret = sch->driver->probe ? sch->driver->probe(sch) : 0;
1241         if (ret)
1242                 sch->driver = NULL;
1243         return ret;
1244 }
1245
1246 static int css_remove(struct device *dev)
1247 {
1248         struct subchannel *sch;
1249         int ret;
1250
1251         sch = to_subchannel(dev);
1252         ret = sch->driver->remove ? sch->driver->remove(sch) : 0;
1253         sch->driver = NULL;
1254         return ret;
1255 }
1256
1257 static void css_shutdown(struct device *dev)
1258 {
1259         struct subchannel *sch;
1260
1261         sch = to_subchannel(dev);
1262         if (sch->driver && sch->driver->shutdown)
1263                 sch->driver->shutdown(sch);
1264 }
1265
1266 static int css_uevent(struct device *dev, struct kobj_uevent_env *env)
1267 {
1268         struct subchannel *sch = to_subchannel(dev);
1269         int ret;
1270
1271         ret = add_uevent_var(env, "ST=%01X", sch->st);
1272         if (ret)
1273                 return ret;
1274         ret = add_uevent_var(env, "MODALIAS=css:t%01X", sch->st);
1275         return ret;
1276 }
1277
1278 static int css_pm_prepare(struct device *dev)
1279 {
1280         struct subchannel *sch = to_subchannel(dev);
1281         struct css_driver *drv;
1282
1283         if (mutex_is_locked(&sch->reg_mutex))
1284                 return -EAGAIN;
1285         if (!sch->dev.driver)
1286                 return 0;
1287         drv = to_cssdriver(sch->dev.driver);
1288         /* Notify drivers that they may not register children. */
1289         return drv->prepare ? drv->prepare(sch) : 0;
1290 }
1291
1292 static void css_pm_complete(struct device *dev)
1293 {
1294         struct subchannel *sch = to_subchannel(dev);
1295         struct css_driver *drv;
1296
1297         if (!sch->dev.driver)
1298                 return;
1299         drv = to_cssdriver(sch->dev.driver);
1300         if (drv->complete)
1301                 drv->complete(sch);
1302 }
1303
1304 static int css_pm_freeze(struct device *dev)
1305 {
1306         struct subchannel *sch = to_subchannel(dev);
1307         struct css_driver *drv;
1308
1309         if (!sch->dev.driver)
1310                 return 0;
1311         drv = to_cssdriver(sch->dev.driver);
1312         return drv->freeze ? drv->freeze(sch) : 0;
1313 }
1314
1315 static int css_pm_thaw(struct device *dev)
1316 {
1317         struct subchannel *sch = to_subchannel(dev);
1318         struct css_driver *drv;
1319
1320         if (!sch->dev.driver)
1321                 return 0;
1322         drv = to_cssdriver(sch->dev.driver);
1323         return drv->thaw ? drv->thaw(sch) : 0;
1324 }
1325
1326 static int css_pm_restore(struct device *dev)
1327 {
1328         struct subchannel *sch = to_subchannel(dev);
1329         struct css_driver *drv;
1330
1331         css_update_ssd_info(sch);
1332         if (!sch->dev.driver)
1333                 return 0;
1334         drv = to_cssdriver(sch->dev.driver);
1335         return drv->restore ? drv->restore(sch) : 0;
1336 }
1337
1338 static const struct dev_pm_ops css_pm_ops = {
1339         .prepare = css_pm_prepare,
1340         .complete = css_pm_complete,
1341         .freeze = css_pm_freeze,
1342         .thaw = css_pm_thaw,
1343         .restore = css_pm_restore,
1344 };
1345
1346 static struct bus_type css_bus_type = {
1347         .name     = "css",
1348         .match    = css_bus_match,
1349         .probe    = css_probe,
1350         .remove   = css_remove,
1351         .shutdown = css_shutdown,
1352         .uevent   = css_uevent,
1353         .pm = &css_pm_ops,
1354 };
1355
1356 /**
1357  * css_driver_register - register a css driver
1358  * @cdrv: css driver to register
1359  *
1360  * This is mainly a wrapper around driver_register that sets name
1361  * and bus_type in the embedded struct device_driver correctly.
1362  */
1363 int css_driver_register(struct css_driver *cdrv)
1364 {
1365         cdrv->drv.bus = &css_bus_type;
1366         return driver_register(&cdrv->drv);
1367 }
1368 EXPORT_SYMBOL_GPL(css_driver_register);
1369
1370 /**
1371  * css_driver_unregister - unregister a css driver
1372  * @cdrv: css driver to unregister
1373  *
1374  * This is a wrapper around driver_unregister.
1375  */
1376 void css_driver_unregister(struct css_driver *cdrv)
1377 {
1378         driver_unregister(&cdrv->drv);
1379 }
1380 EXPORT_SYMBOL_GPL(css_driver_unregister);