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 <linux/genalloc.h>
  24 #include <linux/dma-mapping.h>
  25 #include <asm/isc.h>
  26 #include <asm/crw.h>
  27
  28 #include "css.h"
  29 #include "cio.h"
  30 #include "blacklist.h"
  31 #include "cio_debug.h"
  32 #include "ioasm.h"
  33 #include "chsc.h"
  34 #include "device.h"
  35 #include "idset.h"
  36 #include "chp.h"
  37
  38 int css_init_done = 0;
  39 int max_ssid;
  40
  41 #define MAX_CSS_IDX 0
  42 struct channel_subsystem *channel_subsystems[MAX_CSS_IDX + 1];
  43 static struct bus_type css_bus_type;
  44
  45 int
  46 for_each_subchannel(int(*fn)(struct subchannel_id, void *), void *data)
  47 {
  48         struct subchannel_id schid;
  49         int ret;
  50
  51         init_subchannel_id(&schid);
  52         do {
  53                 do {
  54                         ret = fn(schid, data);
  55                         if (ret)
  56                                 break;
  57                 } while (schid.sch_no++ < __MAX_SUBCHANNEL);
  58                 schid.sch_no = 0;
  59         } while (schid.ssid++ < max_ssid);
  60         return ret;
  61 }
  62
  63 struct cb_data {
  64         void *data;
  65         struct idset *set;
  66         int (*fn_known_sch)(struct subchannel *, void *);
  67         int (*fn_unknown_sch)(struct subchannel_id, void *);
  68 };
  69
  70 static int call_fn_known_sch(struct device *dev, void *data)
  71 {
  72         struct subchannel *sch = to_subchannel(dev);
  73         struct cb_data *cb = data;
  74         int rc = 0;
  75
  76         if (cb->set)
  77                 idset_sch_del(cb->set, sch->schid);
  78         if (cb->fn_known_sch)
  79                 rc = cb->fn_known_sch(sch, cb->data);
  80         return rc;
  81 }
  82
  83 static int call_fn_unknown_sch(struct subchannel_id schid, void *data)
  84 {
  85         struct cb_data *cb = data;
  86         int rc = 0;
  87
  88         if (idset_sch_contains(cb->set, schid))
  89                 rc = cb->fn_unknown_sch(schid, cb->data);
  90         return rc;
  91 }
  92
  93 static int call_fn_all_sch(struct subchannel_id schid, void *data)
  94 {
  95         struct cb_data *cb = data;
  96         struct subchannel *sch;
  97         int rc = 0;
  98
  99         sch = get_subchannel_by_schid(schid);
 100         if (sch) {
 101                 if (cb->fn_known_sch)
 102                         rc = cb->fn_known_sch(sch, cb->data);
 103                 put_device(&sch->dev);
 104         } else {
 105                 if (cb->fn_unknown_sch)
 106                         rc = cb->fn_unknown_sch(schid, cb->data);
 107         }
 108
 109         return rc;
 110 }
 111
 112 int for_each_subchannel_staged(int (*fn_known)(struct subchannel *, void *),
 113                                int (*fn_unknown)(struct subchannel_id,
 114                                void *), void *data)
 115 {
 116         struct cb_data cb;
 117         int rc;
 118
 119         cb.data = data;
 120         cb.fn_known_sch = fn_known;
 121         cb.fn_unknown_sch = fn_unknown;
 122
 123         if (fn_known && !fn_unknown) {
 124                 /* Skip idset allocation in case of known-only loop. */
 125                 cb.set = NULL;
 126                 return bus_for_each_dev(&css_bus_type, NULL, &cb,
 127                                         call_fn_known_sch);
 128         }
 129
 130         cb.set = idset_sch_new();
 131         if (!cb.set)
 132                 /* fall back to brute force scanning in case of oom */
 133                 return for_each_subchannel(call_fn_all_sch, &cb);
 134
 135         idset_fill(cb.set);
 136
 137         /* Process registered subchannels. */
 138         rc = bus_for_each_dev(&css_bus_type, NULL, &cb, call_fn_known_sch);
 139         if (rc)
 140                 goto out;
 141         /* Process unregistered subchannels. */
 142         if (fn_unknown)
 143                 rc = for_each_subchannel(call_fn_unknown_sch, &cb);
 144 out:
 145         idset_free(cb.set);
 146
 147         return rc;
 148 }
 149
 150 static void css_sch_todo(struct work_struct *work);
 151
 152 static int css_sch_create_locks(struct subchannel *sch)
 153 {
 154         sch->lock = kmalloc(sizeof(*sch->lock), GFP_KERNEL);
 155         if (!sch->lock)
 156                 return -ENOMEM;
 157
 158         spin_lock_init(sch->lock);
 159         mutex_init(&sch->reg_mutex);
 160
 161         return 0;
 162 }
 163
 164 static void css_subchannel_release(struct device *dev)
 165 {
 166         struct subchannel *sch = to_subchannel(dev);
 167
 168         sch->config.intparm = 0;
 169         cio_commit_config(sch);
 170         kfree(sch->driver_override);
 171         kfree(sch->lock);
 172         kfree(sch);
 173 }
 174
 175 static int css_validate_subchannel(struct subchannel_id schid,
 176                                    struct schib *schib)
 177 {
 178         int err;
 179
 180         switch (schib->pmcw.st) {
 181         case SUBCHANNEL_TYPE_IO:
 182         case SUBCHANNEL_TYPE_MSG:
 183                 if (!css_sch_is_valid(schib))
 184                         err = -ENODEV;
 185                 else if (is_blacklisted(schid.ssid, schib->pmcw.dev)) {
 186                         CIO_MSG_EVENT(6, "Blacklisted device detected "
 187                                       "at devno %04X, subchannel set %x\n",
 188                                       schib->pmcw.dev, schid.ssid);
 189                         err = -ENODEV;
 190                 } else
 191                         err = 0;
 192                 break;
 193         default:
 194                 err = 0;
 195         }
 196         if (err)
 197                 goto out;
 198
 199         CIO_MSG_EVENT(4, "Subchannel 0.%x.%04x reports subchannel type %04X\n",
 200                       schid.ssid, schid.sch_no, schib->pmcw.st);
 201 out:
 202         return err;
 203 }
 204
 205 struct subchannel *css_alloc_subchannel(struct subchannel_id schid,
 206                                         struct schib *schib)
 207 {
 208         struct subchannel *sch;
 209         int ret;
 210
 211         ret = css_validate_subchannel(schid, schib);
 212         if (ret < 0)
 213                 return ERR_PTR(ret);
 214
 215         sch = kzalloc(sizeof(*sch), GFP_KERNEL | GFP_DMA);
 216         if (!sch)
 217                 return ERR_PTR(-ENOMEM);
 218
 219         sch->schid = schid;
 220         sch->schib = *schib;
 221         sch->st = schib->pmcw.st;
 222
 223         ret = css_sch_create_locks(sch);
 224         if (ret)
 225                 goto err;
 226
 227         INIT_WORK(&sch->todo_work, css_sch_todo);
 228         sch->dev.release = &css_subchannel_release;
 229         device_initialize(&sch->dev);
 230         /*
 231          * The physical addresses of some the dma structures that can
 232          * belong to a subchannel need to fit 31 bit width (e.g. ccw).
 233          */
 234         sch->dev.coherent_dma_mask = DMA_BIT_MASK(31);
 235         /*
 236          * But we don't have such restrictions imposed on the stuff that
 237          * is handled by the streaming API.
 238          */
 239         sch->dma_mask = DMA_BIT_MASK(64);
 240         sch->dev.dma_mask = &sch->dma_mask;
 241         return sch;
 242
 243 err:
 244         kfree(sch);
 245         return ERR_PTR(ret);
 246 }
 247
 248 static int css_sch_device_register(struct subchannel *sch)
 249 {
 250         int ret;
 251
 252         mutex_lock(&sch->reg_mutex);
 253         dev_set_name(&sch->dev, "0.%x.%04x", sch->schid.ssid,
 254                      sch->schid.sch_no);
 255         ret = device_add(&sch->dev);
 256         mutex_unlock(&sch->reg_mutex);
 257         return ret;
 258 }
 259
 260 /**
 261  * css_sch_device_unregister - unregister a subchannel
 262  * @sch: subchannel to be unregistered
 263  */
 264 void css_sch_device_unregister(struct subchannel *sch)
 265 {
 266         mutex_lock(&sch->reg_mutex);
 267         if (device_is_registered(&sch->dev))
 268                 device_unregister(&sch->dev);
 269         mutex_unlock(&sch->reg_mutex);
 270 }
 271 EXPORT_SYMBOL_GPL(css_sch_device_unregister);
 272
 273 static void ssd_from_pmcw(struct chsc_ssd_info *ssd, struct pmcw *pmcw)
 274 {
 275         int i;
 276         int mask;
 277
 278         memset(ssd, 0, sizeof(struct chsc_ssd_info));
 279         ssd->path_mask = pmcw->pim;
 280         for (i = 0; i < 8; i++) {
 281                 mask = 0x80 >> i;
 282                 if (pmcw->pim & mask) {
 283                         chp_id_init(&ssd->chpid[i]);
 284                         ssd->chpid[i].id = pmcw->chpid[i];
 285                 }
 286         }
 287 }
 288
 289 static void ssd_register_chpids(struct chsc_ssd_info *ssd)
 290 {
 291         int i;
 292         int mask;
 293
 294         for (i = 0; i < 8; i++) {
 295                 mask = 0x80 >> i;
 296                 if (ssd->path_mask & mask)
 297                         chp_new(ssd->chpid[i]);
 298         }
 299 }
 300
 301 void css_update_ssd_info(struct subchannel *sch)
 302 {
 303         int ret;
 304
 305         ret = chsc_get_ssd_info(sch->schid, &sch->ssd_info);
 306         if (ret)
 307                 ssd_from_pmcw(&sch->ssd_info, &sch->schib.pmcw);
 308
 309         ssd_register_chpids(&sch->ssd_info);
 310 }
 311
 312 static ssize_t type_show(struct device *dev, struct device_attribute *attr,
 313                          char *buf)
 314 {
 315         struct subchannel *sch = to_subchannel(dev);
 316
 317         return sprintf(buf, "%01x\n", sch->st);
 318 }
 319
 320 static DEVICE_ATTR_RO(type);
 321
 322 static ssize_t modalias_show(struct device *dev, struct device_attribute *attr,
 323                              char *buf)
 324 {
 325         struct subchannel *sch = to_subchannel(dev);
 326
 327         return sprintf(buf, "css:t%01X\n", sch->st);
 328 }
 329
 330 static DEVICE_ATTR_RO(modalias);
 331
 332 static ssize_t driver_override_store(struct device *dev,
 333                                      struct device_attribute *attr,
 334                                      const char *buf, size_t count)
 335 {
 336         struct subchannel *sch = to_subchannel(dev);
 337         char *driver_override, *old, *cp;
 338
 339         /* We need to keep extra room for a newline */
 340         if (count >= (PAGE_SIZE - 1))
 341                 return -EINVAL;
 342
 343         driver_override = kstrndup(buf, count, GFP_KERNEL);
 344         if (!driver_override)
 345                 return -ENOMEM;
 346
 347         cp = strchr(driver_override, '\n');
 348         if (cp)
 349                 *cp = '\0';
 350
 351         device_lock(dev);
 352         old = sch->driver_override;
 353         if (strlen(driver_override)) {
 354                 sch->driver_override = driver_override;
 355         } else {
 356                 kfree(driver_override);
 357                 sch->driver_override = NULL;
 358         }
 359         device_unlock(dev);
 360
 361         kfree(old);
 362
 363         return count;
 364 }
 365
 366 static ssize_t driver_override_show(struct device *dev,
 367                                     struct device_attribute *attr, char *buf)
 368 {
 369         struct subchannel *sch = to_subchannel(dev);
 370         ssize_t len;
 371
 372         device_lock(dev);
 373         len = snprintf(buf, PAGE_SIZE, "%s\n", sch->driver_override);
 374         device_unlock(dev);
 375         return len;
 376 }
 377 static DEVICE_ATTR_RW(driver_override);
 378
 379 static struct attribute *subch_attrs[] = {
 380         &dev_attr_type.attr,
 381         &dev_attr_modalias.attr,
 382         &dev_attr_driver_override.attr,
 383         NULL,
 384 };
 385
 386 static struct attribute_group subch_attr_group = {
 387         .attrs = subch_attrs,
 388 };
 389
 390 static const struct attribute_group *default_subch_attr_groups[] = {
 391         &subch_attr_group,
 392         NULL,
 393 };
 394
 395 static ssize_t chpids_show(struct device *dev,
 396                            struct device_attribute *attr,
 397                            char *buf)
 398 {
 399         struct subchannel *sch = to_subchannel(dev);
 400         struct chsc_ssd_info *ssd = &sch->ssd_info;
 401         ssize_t ret = 0;
 402         int mask;
 403         int chp;
 404
 405         for (chp = 0; chp < 8; chp++) {
 406                 mask = 0x80 >> chp;
 407                 if (ssd->path_mask & mask)
 408                         ret += sprintf(buf + ret, "%02x ", ssd->chpid[chp].id);
 409                 else
 410                         ret += sprintf(buf + ret, "00 ");
 411         }
 412         ret += sprintf(buf + ret, "\n");
 413         return ret;
 414 }
 415 static DEVICE_ATTR_RO(chpids);
 416
 417 static ssize_t pimpampom_show(struct device *dev,
 418                               struct device_attribute *attr,
 419                               char *buf)
 420 {
 421         struct subchannel *sch = to_subchannel(dev);
 422         struct pmcw *pmcw = &sch->schib.pmcw;
 423
 424         return sprintf(buf, "%02x %02x %02x\n",
 425                        pmcw->pim, pmcw->pam, pmcw->pom);
 426 }
 427 static DEVICE_ATTR_RO(pimpampom);
 428
 429 static ssize_t dev_busid_show(struct device *dev,
 430                               struct device_attribute *attr,
 431                               char *buf)
 432 {
 433         struct subchannel *sch = to_subchannel(dev);
 434         struct pmcw *pmcw = &sch->schib.pmcw;
 435
 436         if ((pmcw->st == SUBCHANNEL_TYPE_IO && pmcw->dnv) ||
 437             (pmcw->st == SUBCHANNEL_TYPE_MSG && pmcw->w))
 438                 return sysfs_emit(buf, "0.%x.%04x\n", sch->schid.ssid,
 439                                   pmcw->dev);
 440         else
 441                 return sysfs_emit(buf, "none\n");
 442 }
 443 static DEVICE_ATTR_RO(dev_busid);
 444
 445 static struct attribute *io_subchannel_type_attrs[] = {
 446         &dev_attr_chpids.attr,
 447         &dev_attr_pimpampom.attr,
 448         &dev_attr_dev_busid.attr,
 449         NULL,
 450 };
 451 ATTRIBUTE_GROUPS(io_subchannel_type);
 452
 453 static const struct device_type io_subchannel_type = {
 454         .groups = io_subchannel_type_groups,
 455 };
 456
 457 int css_register_subchannel(struct subchannel *sch)
 458 {
 459         int ret;
 460
 461         /* Initialize the subchannel structure */
 462         sch->dev.parent = &channel_subsystems[0]->device;
 463         sch->dev.bus = &css_bus_type;
 464         sch->dev.groups = default_subch_attr_groups;
 465
 466         if (sch->st == SUBCHANNEL_TYPE_IO)
 467                 sch->dev.type = &io_subchannel_type;
 468
 469         /*
 470          * We don't want to generate uevents for I/O subchannels that don't
 471          * have a working ccw device behind them since they will be
 472          * unregistered before they can be used anyway, so we delay the add
 473          * uevent until after device recognition was successful.
 474          * Note that we suppress the uevent for all subchannel types;
 475          * the subchannel driver can decide itself when it wants to inform
 476          * userspace of its existence.
 477          */
 478         dev_set_uevent_suppress(&sch->dev, 1);
 479         css_update_ssd_info(sch);
 480         /* make it known to the system */
 481         ret = css_sch_device_register(sch);
 482         if (ret) {
 483                 CIO_MSG_EVENT(0, "Could not register sch 0.%x.%04x: %d\n",
 484                               sch->schid.ssid, sch->schid.sch_no, ret);
 485                 return ret;
 486         }
 487         if (!sch->driver) {
 488                 /*
 489                  * No driver matched. Generate the uevent now so that
 490                  * a fitting driver module may be loaded based on the
 491                  * modalias.
 492                  */
 493                 dev_set_uevent_suppress(&sch->dev, 0);
 494                 kobject_uevent(&sch->dev.kobj, KOBJ_ADD);
 495         }
 496         return ret;
 497 }
 498
 499 static int css_probe_device(struct subchannel_id schid, struct schib *schib)
 500 {
 501         struct subchannel *sch;
 502         int ret;
 503
 504         sch = css_alloc_subchannel(schid, schib);
 505         if (IS_ERR(sch))
 506                 return PTR_ERR(sch);
 507
 508         ret = css_register_subchannel(sch);
 509         if (ret)
 510                 put_device(&sch->dev);
 511
 512         return ret;
 513 }
 514
 515 static int
 516 check_subchannel(struct device *dev, const void *data)
 517 {
 518         struct subchannel *sch;
 519         struct subchannel_id *schid = (void *)data;
 520
 521         sch = to_subchannel(dev);
 522         return schid_equal(&sch->schid, schid);
 523 }
 524
 525 struct subchannel *
 526 get_subchannel_by_schid(struct subchannel_id schid)
 527 {
 528         struct device *dev;
 529
 530         dev = bus_find_device(&css_bus_type, NULL,
 531                               &schid, check_subchannel);
 532
 533         return dev ? to_subchannel(dev) : NULL;
 534 }
 535
 536 /**
 537  * css_sch_is_valid() - check if a subchannel is valid
 538  * @schib: subchannel information block for the subchannel
 539  */
 540 int css_sch_is_valid(struct schib *schib)
 541 {
 542         if ((schib->pmcw.st == SUBCHANNEL_TYPE_IO) && !schib->pmcw.dnv)
 543                 return 0;
 544         if ((schib->pmcw.st == SUBCHANNEL_TYPE_MSG) && !schib->pmcw.w)
 545                 return 0;
 546         return 1;
 547 }
 548 EXPORT_SYMBOL_GPL(css_sch_is_valid);
 549
 550 static int css_evaluate_new_subchannel(struct subchannel_id schid, int slow)
 551 {
 552         struct schib schib;
 553         int ccode;
 554
 555         if (!slow) {
 556                 /* Will be done on the slow path. */
 557                 return -EAGAIN;
 558         }
 559         /*
 560          * The first subchannel that is not-operational (ccode==3)
 561          * indicates that there aren't any more devices available.
 562          * If stsch gets an exception, it means the current subchannel set
 563          * is not valid.
 564          */
 565         ccode = stsch(schid, &schib);
 566         if (ccode)
 567                 return (ccode == 3) ? -ENXIO : ccode;
 568
 569         return css_probe_device(schid, &schib);
 570 }
 571
 572 static int css_evaluate_known_subchannel(struct subchannel *sch, int slow)
 573 {
 574         int ret = 0;
 575
 576         if (sch->driver) {
 577                 if (sch->driver->sch_event)
 578                         ret = sch->driver->sch_event(sch, slow);
 579                 else
 580                         dev_dbg(&sch->dev,
 581                                 "Got subchannel machine check but "
 582                                 "no sch_event handler provided.\n");
 583         }
 584         if (ret != 0 && ret != -EAGAIN) {
 585                 CIO_MSG_EVENT(2, "eval: sch 0.%x.%04x, rc=%d\n",
 586                               sch->schid.ssid, sch->schid.sch_no, ret);
 587         }
 588         return ret;
 589 }
 590
 591 static void css_evaluate_subchannel(struct subchannel_id schid, int slow)
 592 {
 593         struct subchannel *sch;
 594         int ret;
 595
 596         sch = get_subchannel_by_schid(schid);
 597         if (sch) {
 598                 ret = css_evaluate_known_subchannel(sch, slow);
 599                 put_device(&sch->dev);
 600         } else
 601                 ret = css_evaluate_new_subchannel(schid, slow);
 602         if (ret == -EAGAIN)
 603                 css_schedule_eval(schid);
 604 }
 605
 606 /**
 607  * css_sched_sch_todo - schedule a subchannel operation
 608  * @sch: subchannel
 609  * @todo: todo
 610  *
 611  * Schedule the operation identified by @todo to be performed on the slow path
 612  * workqueue. Do nothing if another operation with higher priority is already
 613  * scheduled. Needs to be called with subchannel lock held.
 614  */
 615 void css_sched_sch_todo(struct subchannel *sch, enum sch_todo todo)
 616 {
 617         CIO_MSG_EVENT(4, "sch_todo: sched sch=0.%x.%04x todo=%d\n",
 618                       sch->schid.ssid, sch->schid.sch_no, todo);
 619         if (sch->todo >= todo)
 620                 return;
 621         /* Get workqueue ref. */
 622         if (!get_device(&sch->dev))
 623                 return;
 624         sch->todo = todo;
 625         if (!queue_work(cio_work_q, &sch->todo_work)) {
 626                 /* Already queued, release workqueue ref. */
 627                 put_device(&sch->dev);
 628         }
 629 }
 630 EXPORT_SYMBOL_GPL(css_sched_sch_todo);
 631
 632 static void css_sch_todo(struct work_struct *work)
 633 {
 634         struct subchannel *sch;
 635         enum sch_todo todo;
 636         int ret;
 637
 638         sch = container_of(work, struct subchannel, todo_work);
 639         /* Find out todo. */
 640         spin_lock_irq(sch->lock);
 641         todo = sch->todo;
 642         CIO_MSG_EVENT(4, "sch_todo: sch=0.%x.%04x, todo=%d\n", sch->schid.ssid,
 643                       sch->schid.sch_no, todo);
 644         sch->todo = SCH_TODO_NOTHING;
 645         spin_unlock_irq(sch->lock);
 646         /* Perform todo. */
 647         switch (todo) {
 648         case SCH_TODO_NOTHING:
 649                 break;
 650         case SCH_TODO_EVAL:
 651                 ret = css_evaluate_known_subchannel(sch, 1);
 652                 if (ret == -EAGAIN) {
 653                         spin_lock_irq(sch->lock);
 654                         css_sched_sch_todo(sch, todo);
 655                         spin_unlock_irq(sch->lock);
 656                 }
 657                 break;
 658         case SCH_TODO_UNREG:
 659                 css_sch_device_unregister(sch);
 660                 break;
 661         }
 662         /* Release workqueue ref. */
 663         put_device(&sch->dev);
 664 }
 665
 666 static struct idset *slow_subchannel_set;
 667 static spinlock_t slow_subchannel_lock;
 668 static wait_queue_head_t css_eval_wq;
 669 static atomic_t css_eval_scheduled;
 670
 671 static int __init slow_subchannel_init(void)
 672 {
 673         spin_lock_init(&slow_subchannel_lock);
 674         atomic_set(&css_eval_scheduled, 0);
 675         init_waitqueue_head(&css_eval_wq);
 676         slow_subchannel_set = idset_sch_new();
 677         if (!slow_subchannel_set) {
 678                 CIO_MSG_EVENT(0, "could not allocate slow subchannel set\n");
 679                 return -ENOMEM;
 680         }
 681         return 0;
 682 }
 683
 684 static int slow_eval_known_fn(struct subchannel *sch, void *data)
 685 {
 686         int eval;
 687         int rc;
 688
 689         spin_lock_irq(&slow_subchannel_lock);
 690         eval = idset_sch_contains(slow_subchannel_set, sch->schid);
 691         idset_sch_del(slow_subchannel_set, sch->schid);
 692         spin_unlock_irq(&slow_subchannel_lock);
 693         if (eval) {
 694                 rc = css_evaluate_known_subchannel(sch, 1);
 695                 if (rc == -EAGAIN)
 696                         css_schedule_eval(sch->schid);
 697                 /*
 698                  * The loop might take long time for platforms with lots of
 699                  * known devices. Allow scheduling here.
 700                  */
 701                 cond_resched();
 702         }
 703         return 0;
 704 }
 705
 706 static int slow_eval_unknown_fn(struct subchannel_id schid, void *data)
 707 {
 708         int eval;
 709         int rc = 0;
 710
 711         spin_lock_irq(&slow_subchannel_lock);
 712         eval = idset_sch_contains(slow_subchannel_set, schid);
 713         idset_sch_del(slow_subchannel_set, schid);
 714         spin_unlock_irq(&slow_subchannel_lock);
 715         if (eval) {
 716                 rc = css_evaluate_new_subchannel(schid, 1);
 717                 switch (rc) {
 718                 case -EAGAIN:
 719                         css_schedule_eval(schid);
 720                         rc = 0;
 721                         break;
 722                 case -ENXIO:
 723                 case -ENOMEM:
 724                 case -EIO:
 725                         /* These should abort looping */
 726                         spin_lock_irq(&slow_subchannel_lock);
 727                         idset_sch_del_subseq(slow_subchannel_set, schid);
 728                         spin_unlock_irq(&slow_subchannel_lock);
 729                         break;
 730                 default:
 731                         rc = 0;
 732                 }
 733                 /* Allow scheduling here since the containing loop might
 734                  * take a while.  */
 735                 cond_resched();
 736         }
 737         return rc;
 738 }
 739
 740 static void css_slow_path_func(struct work_struct *unused)
 741 {
 742         unsigned long flags;
 743
 744         CIO_TRACE_EVENT(4, "slowpath");
 745         for_each_subchannel_staged(slow_eval_known_fn, slow_eval_unknown_fn,
 746                                    NULL);
 747         spin_lock_irqsave(&slow_subchannel_lock, flags);
 748         if (idset_is_empty(slow_subchannel_set)) {
 749                 atomic_set(&css_eval_scheduled, 0);
 750                 wake_up(&css_eval_wq);
 751         }
 752         spin_unlock_irqrestore(&slow_subchannel_lock, flags);
 753 }
 754
 755 static DECLARE_DELAYED_WORK(slow_path_work, css_slow_path_func);
 756 struct workqueue_struct *cio_work_q;
 757
 758 void css_schedule_eval(struct subchannel_id schid)
 759 {
 760         unsigned long flags;
 761
 762         spin_lock_irqsave(&slow_subchannel_lock, flags);
 763         idset_sch_add(slow_subchannel_set, schid);
 764         atomic_set(&css_eval_scheduled, 1);
 765         queue_delayed_work(cio_work_q, &slow_path_work, 0);
 766         spin_unlock_irqrestore(&slow_subchannel_lock, flags);
 767 }
 768
 769 void css_schedule_eval_all(void)
 770 {
 771         unsigned long flags;
 772
 773         spin_lock_irqsave(&slow_subchannel_lock, flags);
 774         idset_fill(slow_subchannel_set);
 775         atomic_set(&css_eval_scheduled, 1);
 776         queue_delayed_work(cio_work_q, &slow_path_work, 0);
 777         spin_unlock_irqrestore(&slow_subchannel_lock, flags);
 778 }
 779
 780 static int __unset_registered(struct device *dev, void *data)
 781 {
 782         struct idset *set = data;
 783         struct subchannel *sch = to_subchannel(dev);
 784
 785         idset_sch_del(set, sch->schid);
 786         return 0;
 787 }
 788
 789 void css_schedule_eval_all_unreg(unsigned long delay)
 790 {
 791         unsigned long flags;
 792         struct idset *unreg_set;
 793
 794         /* Find unregistered subchannels. */
 795         unreg_set = idset_sch_new();
 796         if (!unreg_set) {
 797                 /* Fallback. */
 798                 css_schedule_eval_all();
 799                 return;
 800         }
 801         idset_fill(unreg_set);
 802         bus_for_each_dev(&css_bus_type, NULL, unreg_set, __unset_registered);
 803         /* Apply to slow_subchannel_set. */
 804         spin_lock_irqsave(&slow_subchannel_lock, flags);
 805         idset_add_set(slow_subchannel_set, unreg_set);
 806         atomic_set(&css_eval_scheduled, 1);
 807         queue_delayed_work(cio_work_q, &slow_path_work, delay);
 808         spin_unlock_irqrestore(&slow_subchannel_lock, flags);
 809         idset_free(unreg_set);
 810 }
 811
 812 void css_wait_for_slow_path(void)
 813 {
 814         flush_workqueue(cio_work_q);
 815 }
 816
 817 /* Schedule reprobing of all unregistered subchannels. */
 818 void css_schedule_reprobe(void)
 819 {
 820         /* Schedule with a delay to allow merging of subsequent calls. */
 821         css_schedule_eval_all_unreg(1 * HZ);
 822 }
 823 EXPORT_SYMBOL_GPL(css_schedule_reprobe);
 824
 825 /*
 826  * Called from the machine check handler for subchannel report words.
 827  */
 828 static void css_process_crw(struct crw *crw0, struct crw *crw1, int overflow)
 829 {
 830         struct subchannel_id mchk_schid;
 831         struct subchannel *sch;
 832
 833         if (overflow) {
 834                 css_schedule_eval_all();
 835                 return;
 836         }
 837         CIO_CRW_EVENT(2, "CRW0 reports slct=%d, oflw=%d, "
 838                       "chn=%d, rsc=%X, anc=%d, erc=%X, rsid=%X\n",
 839                       crw0->slct, crw0->oflw, crw0->chn, crw0->rsc, crw0->anc,
 840                       crw0->erc, crw0->rsid);
 841         if (crw1)
 842                 CIO_CRW_EVENT(2, "CRW1 reports slct=%d, oflw=%d, "
 843                               "chn=%d, rsc=%X, anc=%d, erc=%X, rsid=%X\n",
 844                               crw1->slct, crw1->oflw, crw1->chn, crw1->rsc,
 845                               crw1->anc, crw1->erc, crw1->rsid);
 846         init_subchannel_id(&mchk_schid);
 847         mchk_schid.sch_no = crw0->rsid;
 848         if (crw1)
 849                 mchk_schid.ssid = (crw1->rsid >> 4) & 3;
 850
 851         if (crw0->erc == CRW_ERC_PMOD) {
 852                 sch = get_subchannel_by_schid(mchk_schid);
 853                 if (sch) {
 854                         css_update_ssd_info(sch);
 855                         put_device(&sch->dev);
 856                 }
 857         }
 858         /*
 859          * Since we are always presented with IPI in the CRW, we have to
 860          * use stsch() to find out if the subchannel in question has come
 861          * or gone.
 862          */
 863         css_evaluate_subchannel(mchk_schid, 0);
 864 }
 865
 866 static void __init
 867 css_generate_pgid(struct channel_subsystem *css, u32 tod_high)
 868 {
 869         struct cpuid cpu_id;
 870
 871         if (css_general_characteristics.mcss) {
 872                 css->global_pgid.pgid_high.ext_cssid.version = 0x80;
 873                 css->global_pgid.pgid_high.ext_cssid.cssid =
 874                         css->id_valid ? css->cssid : 0;
 875         } else {
 876                 css->global_pgid.pgid_high.cpu_addr = stap();
 877         }
 878         get_cpu_id(&cpu_id);
 879         css->global_pgid.cpu_id = cpu_id.ident;
 880         css->global_pgid.cpu_model = cpu_id.machine;
 881         css->global_pgid.tod_high = tod_high;
 882 }
 883
 884 static void channel_subsystem_release(struct device *dev)
 885 {
 886         struct channel_subsystem *css = to_css(dev);
 887
 888         mutex_destroy(&css->mutex);
 889         kfree(css);
 890 }
 891
 892 static ssize_t real_cssid_show(struct device *dev, struct device_attribute *a,
 893                                char *buf)
 894 {
 895         struct channel_subsystem *css = to_css(dev);
 896
 897         if (!css->id_valid)
 898                 return -EINVAL;
 899
 900         return sprintf(buf, "%x\n", css->cssid);
 901 }
 902 static DEVICE_ATTR_RO(real_cssid);
 903
 904 static ssize_t cm_enable_show(struct device *dev, struct device_attribute *a,
 905                               char *buf)
 906 {
 907         struct channel_subsystem *css = to_css(dev);
 908         int ret;
 909
 910         mutex_lock(&css->mutex);
 911         ret = sprintf(buf, "%x\n", css->cm_enabled);
 912         mutex_unlock(&css->mutex);
 913         return ret;
 914 }
 915
 916 static ssize_t cm_enable_store(struct device *dev, struct device_attribute *a,
 917                                const char *buf, size_t count)
 918 {
 919         struct channel_subsystem *css = to_css(dev);
 920         unsigned long val;
 921         int ret;
 922
 923         ret = kstrtoul(buf, 16, &val);
 924         if (ret)
 925                 return ret;
 926         mutex_lock(&css->mutex);
 927         switch (val) {
 928         case 0:
 929                 ret = css->cm_enabled ? chsc_secm(css, 0) : 0;
 930                 break;
 931         case 1:
 932                 ret = css->cm_enabled ? 0 : chsc_secm(css, 1);
 933                 break;
 934         default:
 935                 ret = -EINVAL;
 936         }
 937         mutex_unlock(&css->mutex);
 938         return ret < 0 ? ret : count;
 939 }
 940 static DEVICE_ATTR_RW(cm_enable);
 941
 942 static umode_t cm_enable_mode(struct kobject *kobj, struct attribute *attr,
 943                               int index)
 944 {
 945         return css_chsc_characteristics.secm ? attr->mode : 0;
 946 }
 947
 948 static struct attribute *cssdev_attrs[] = {
 949         &dev_attr_real_cssid.attr,
 950         NULL,
 951 };
 952
 953 static struct attribute_group cssdev_attr_group = {
 954         .attrs = cssdev_attrs,
 955 };
 956
 957 static struct attribute *cssdev_cm_attrs[] = {
 958         &dev_attr_cm_enable.attr,
 959         NULL,
 960 };
 961
 962 static struct attribute_group cssdev_cm_attr_group = {
 963         .attrs = cssdev_cm_attrs,
 964         .is_visible = cm_enable_mode,
 965 };
 966
 967 static const struct attribute_group *cssdev_attr_groups[] = {
 968         &cssdev_attr_group,
 969         &cssdev_cm_attr_group,
 970         NULL,
 971 };
 972
 973 static int __init setup_css(int nr)
 974 {
 975         struct channel_subsystem *css;
 976         int ret;
 977
 978         css = kzalloc(sizeof(*css), GFP_KERNEL);
 979         if (!css)
 980                 return -ENOMEM;
 981
 982         channel_subsystems[nr] = css;
 983         dev_set_name(&css->device, "css%x", nr);
 984         css->device.groups = cssdev_attr_groups;
 985         css->device.release = channel_subsystem_release;
 986         /*
 987          * We currently allocate notifier bits with this (using
 988          * css->device as the device argument with the DMA API)
 989          * and are fine with 64 bit addresses.
 990          */
 991         css->device.coherent_dma_mask = DMA_BIT_MASK(64);
 992         css->device.dma_mask = &css->device.coherent_dma_mask;
 993
 994         mutex_init(&css->mutex);
 995         ret = chsc_get_cssid_iid(nr, &css->cssid, &css->iid);
 996         if (!ret) {
 997                 css->id_valid = true;
 998                 pr_info("Partition identifier %01x.%01x\n", css->cssid,
 999                         css->iid);
1000         }
1001         css_generate_pgid(css, (u32) (get_tod_clock() >> 32));
1002
1003         ret = device_register(&css->device);
1004         if (ret) {
1005                 put_device(&css->device);
1006                 goto out_err;
1007         }
1008
1009         css->pseudo_subchannel = kzalloc(sizeof(*css->pseudo_subchannel),
1010                                          GFP_KERNEL);
1011         if (!css->pseudo_subchannel) {
1012                 device_unregister(&css->device);
1013                 ret = -ENOMEM;
1014                 goto out_err;
1015         }
1016
1017         css->pseudo_subchannel->dev.parent = &css->device;
1018         css->pseudo_subchannel->dev.release = css_subchannel_release;
1019         mutex_init(&css->pseudo_subchannel->reg_mutex);
1020         ret = css_sch_create_locks(css->pseudo_subchannel);
1021         if (ret) {
1022                 kfree(css->pseudo_subchannel);
1023                 device_unregister(&css->device);
1024                 goto out_err;
1025         }
1026
1027         dev_set_name(&css->pseudo_subchannel->dev, "defunct");
1028         ret = device_register(&css->pseudo_subchannel->dev);
1029         if (ret) {
1030                 put_device(&css->pseudo_subchannel->dev);
1031                 device_unregister(&css->device);
1032                 goto out_err;
1033         }
1034
1035         return ret;
1036 out_err:
1037         channel_subsystems[nr] = NULL;
1038         return ret;
1039 }
1040
1041 static int css_reboot_event(struct notifier_block *this,
1042                             unsigned long event,
1043                             void *ptr)
1044 {
1045         struct channel_subsystem *css;
1046         int ret;
1047
1048         ret = NOTIFY_DONE;
1049         for_each_css(css) {
1050                 mutex_lock(&css->mutex);
1051                 if (css->cm_enabled)
1052                         if (chsc_secm(css, 0))
1053                                 ret = NOTIFY_BAD;
1054                 mutex_unlock(&css->mutex);
1055         }
1056
1057         return ret;
1058 }
1059
1060 static struct notifier_block css_reboot_notifier = {
1061         .notifier_call = css_reboot_event,
1062 };
1063
1064 /*
1065  * Since the css devices are neither on a bus nor have a class
1066  * nor have a special device type, we cannot stop/restart channel
1067  * path measurements via the normal suspend/resume callbacks, but have
1068  * to use notifiers.
1069  */
1070 static int css_power_event(struct notifier_block *this, unsigned long event,
1071                            void *ptr)
1072 {
1073         struct channel_subsystem *css;
1074         int ret;
1075
1076         switch (event) {
1077         case PM_HIBERNATION_PREPARE:
1078         case PM_SUSPEND_PREPARE:
1079                 ret = NOTIFY_DONE;
1080                 for_each_css(css) {
1081                         mutex_lock(&css->mutex);
1082                         if (!css->cm_enabled) {
1083                                 mutex_unlock(&css->mutex);
1084                                 continue;
1085                         }
1086                         ret = __chsc_do_secm(css, 0);
1087                         ret = notifier_from_errno(ret);
1088                         mutex_unlock(&css->mutex);
1089                 }
1090                 break;
1091         case PM_POST_HIBERNATION:
1092         case PM_POST_SUSPEND:
1093                 ret = NOTIFY_DONE;
1094                 for_each_css(css) {
1095                         mutex_lock(&css->mutex);
1096                         if (!css->cm_enabled) {
1097                                 mutex_unlock(&css->mutex);
1098                                 continue;
1099                         }
1100                         ret = __chsc_do_secm(css, 1);
1101                         ret = notifier_from_errno(ret);
1102                         mutex_unlock(&css->mutex);
1103                 }
1104                 /* search for subchannels, which appeared during hibernation */
1105                 css_schedule_reprobe();
1106                 break;
1107         default:
1108                 ret = NOTIFY_DONE;
1109         }
1110         return ret;
1111
1112 }
1113 static struct notifier_block css_power_notifier = {
1114         .notifier_call = css_power_event,
1115 };
1116
1117 #define  CIO_DMA_GFP (GFP_KERNEL | __GFP_ZERO)
1118 static struct gen_pool *cio_dma_pool;
1119
1120 /* Currently cio supports only a single css */
1121 struct device *cio_get_dma_css_dev(void)
1122 {
1123         return &channel_subsystems[0]->device;
1124 }
1125
1126 struct gen_pool *cio_gp_dma_create(struct device *dma_dev, int nr_pages)
1127 {
1128         struct gen_pool *gp_dma;
1129         void *cpu_addr;
1130         dma_addr_t dma_addr;
1131         int i;
1132
1133         gp_dma = gen_pool_create(3, -1);
1134         if (!gp_dma)
1135                 return NULL;
1136         for (i = 0; i < nr_pages; ++i) {
1137                 cpu_addr = dma_alloc_coherent(dma_dev, PAGE_SIZE, &dma_addr,
1138                                               CIO_DMA_GFP);
1139                 if (!cpu_addr)
1140                         return gp_dma;
1141                 gen_pool_add_virt(gp_dma, (unsigned long) cpu_addr,
1142                                   dma_addr, PAGE_SIZE, -1);
1143         }
1144         return gp_dma;
1145 }
1146
1147 static void __gp_dma_free_dma(struct gen_pool *pool,
1148                               struct gen_pool_chunk *chunk, void *data)
1149 {
1150         size_t chunk_size = chunk->end_addr - chunk->start_addr + 1;
1151
1152         dma_free_coherent((struct device *) data, chunk_size,
1153                          (void *) chunk->start_addr,
1154                          (dma_addr_t) chunk->phys_addr);
1155 }
1156
1157 void cio_gp_dma_destroy(struct gen_pool *gp_dma, struct device *dma_dev)
1158 {
1159         if (!gp_dma)
1160                 return;
1161         /* this is quite ugly but no better idea */
1162         gen_pool_for_each_chunk(gp_dma, __gp_dma_free_dma, dma_dev);
1163         gen_pool_destroy(gp_dma);
1164 }
1165
1166 static int cio_dma_pool_init(void)
1167 {
1168         /* No need to free up the resources: compiled in */
1169         cio_dma_pool = cio_gp_dma_create(cio_get_dma_css_dev(), 1);
1170         if (!cio_dma_pool)
1171                 return -ENOMEM;
1172         return 0;
1173 }
1174
1175 void *cio_gp_dma_zalloc(struct gen_pool *gp_dma, struct device *dma_dev,
1176                         size_t size)
1177 {
1178         dma_addr_t dma_addr;
1179         unsigned long addr;
1180         size_t chunk_size;
1181
1182         if (!gp_dma)
1183                 return NULL;
1184         addr = gen_pool_alloc(gp_dma, size);
1185         while (!addr) {
1186                 chunk_size = round_up(size, PAGE_SIZE);
1187                 addr = (unsigned long) dma_alloc_coherent(dma_dev,
1188                                          chunk_size, &dma_addr, CIO_DMA_GFP);
1189                 if (!addr)
1190                         return NULL;
1191                 gen_pool_add_virt(gp_dma, addr, dma_addr, chunk_size, -1);
1192                 addr = gen_pool_alloc(gp_dma, size);
1193         }
1194         return (void *) addr;
1195 }
1196
1197 void cio_gp_dma_free(struct gen_pool *gp_dma, void *cpu_addr, size_t size)
1198 {
1199         if (!cpu_addr)
1200                 return;
1201         memset(cpu_addr, 0, size);
1202         gen_pool_free(gp_dma, (unsigned long) cpu_addr, size);
1203 }
1204
1205 /*
1206  * Allocate dma memory from the css global pool. Intended for memory not
1207  * specific to any single device within the css. The allocated memory
1208  * is not guaranteed to be 31-bit addressable.
1209  *
1210  * Caution: Not suitable for early stuff like console.
1211  */
1212 void *cio_dma_zalloc(size_t size)
1213 {
1214         return cio_gp_dma_zalloc(cio_dma_pool, cio_get_dma_css_dev(), size);
1215 }
1216
1217 void cio_dma_free(void *cpu_addr, size_t size)
1218 {
1219         cio_gp_dma_free(cio_dma_pool, cpu_addr, size);
1220 }
1221
1222 /*
1223  * Now that the driver core is running, we can setup our channel subsystem.
1224  * The struct subchannel's are created during probing.
1225  */
1226 static int __init css_bus_init(void)
1227 {
1228         int ret, i;
1229
1230         ret = chsc_init();
1231         if (ret)
1232                 return ret;
1233
1234         chsc_determine_css_characteristics();
1235         /* Try to enable MSS. */
1236         ret = chsc_enable_facility(CHSC_SDA_OC_MSS);
1237         if (ret)
1238                 max_ssid = 0;
1239         else /* Success. */
1240                 max_ssid = __MAX_SSID;
1241
1242         ret = slow_subchannel_init();
1243         if (ret)
1244                 goto out;
1245
1246         ret = crw_register_handler(CRW_RSC_SCH, css_process_crw);
1247         if (ret)
1248                 goto out;
1249
1250         if ((ret = bus_register(&css_bus_type)))
1251                 goto out;
1252
1253         /* Setup css structure. */
1254         for (i = 0; i <= MAX_CSS_IDX; i++) {
1255                 ret = setup_css(i);
1256                 if (ret)
1257                         goto out_unregister;
1258         }
1259         ret = register_reboot_notifier(&css_reboot_notifier);
1260         if (ret)
1261                 goto out_unregister;
1262         ret = register_pm_notifier(&css_power_notifier);
1263         if (ret)
1264                 goto out_unregister_rn;
1265         ret = cio_dma_pool_init();
1266         if (ret)
1267                 goto out_unregister_pmn;
1268         airq_init();
1269         css_init_done = 1;
1270
1271         /* Enable default isc for I/O subchannels. */
1272         isc_register(IO_SCH_ISC);
1273
1274         return 0;
1275 out_unregister_pmn:
1276         unregister_pm_notifier(&css_power_notifier);
1277 out_unregister_rn:
1278         unregister_reboot_notifier(&css_reboot_notifier);
1279 out_unregister:
1280         while (i-- > 0) {
1281                 struct channel_subsystem *css = channel_subsystems[i];
1282                 device_unregister(&css->pseudo_subchannel->dev);
1283                 device_unregister(&css->device);
1284         }
1285         bus_unregister(&css_bus_type);
1286 out:
1287         crw_unregister_handler(CRW_RSC_SCH);
1288         idset_free(slow_subchannel_set);
1289         chsc_init_cleanup();
1290         pr_alert("The CSS device driver initialization failed with "
1291                  "errno=%d\n", ret);
1292         return ret;
1293 }
1294
1295 static void __init css_bus_cleanup(void)
1296 {
1297         struct channel_subsystem *css;
1298
1299         for_each_css(css) {
1300                 device_unregister(&css->pseudo_subchannel->dev);
1301                 device_unregister(&css->device);
1302         }
1303         bus_unregister(&css_bus_type);
1304         crw_unregister_handler(CRW_RSC_SCH);
1305         idset_free(slow_subchannel_set);
1306         chsc_init_cleanup();
1307         isc_unregister(IO_SCH_ISC);
1308 }
1309
1310 static int __init channel_subsystem_init(void)
1311 {
1312         int ret;
1313
1314         ret = css_bus_init();
1315         if (ret)
1316                 return ret;
1317         cio_work_q = create_singlethread_workqueue("cio");
1318         if (!cio_work_q) {
1319                 ret = -ENOMEM;
1320                 goto out_bus;
1321         }
1322         ret = io_subchannel_init();
1323         if (ret)
1324                 goto out_wq;
1325
1326         /* Register subchannels which are already in use. */
1327         cio_register_early_subchannels();
1328         /* Start initial subchannel evaluation. */
1329         css_schedule_eval_all();
1330
1331         return ret;
1332 out_wq:
1333         destroy_workqueue(cio_work_q);
1334 out_bus:
1335         css_bus_cleanup();
1336         return ret;
1337 }
1338 subsys_initcall(channel_subsystem_init);
1339
1340 static int css_settle(struct device_driver *drv, void *unused)
1341 {
1342         struct css_driver *cssdrv = to_cssdriver(drv);
1343
1344         if (cssdrv->settle)
1345                 return cssdrv->settle();
1346         return 0;
1347 }
1348
1349 int css_complete_work(void)
1350 {
1351         int ret;
1352
1353         /* Wait for the evaluation of subchannels to finish. */
1354         ret = wait_event_interruptible(css_eval_wq,
1355                                        atomic_read(&css_eval_scheduled) == 0);
1356         if (ret)
1357                 return -EINTR;
1358         flush_workqueue(cio_work_q);
1359         /* Wait for the subchannel type specific initialization to finish */
1360         return bus_for_each_drv(&css_bus_type, NULL, NULL, css_settle);
1361 }
1362
1363
1364 /*
1365  * Wait for the initialization of devices to finish, to make sure we are
1366  * done with our setup if the search for the root device starts.
1367  */
1368 static int __init channel_subsystem_init_sync(void)
1369 {
1370         css_complete_work();
1371         return 0;
1372 }
1373 subsys_initcall_sync(channel_subsystem_init_sync);
1374
1375 #ifdef CONFIG_PROC_FS
1376 static ssize_t cio_settle_write(struct file *file, const char __user *buf,
1377                                 size_t count, loff_t *ppos)
1378 {
1379         int ret;
1380
1381         /* Handle pending CRW's. */
1382         crw_wait_for_channel_report();
1383         ret = css_complete_work();
1384
1385         return ret ? ret : count;
1386 }
1387
1388 static const struct proc_ops cio_settle_proc_ops = {
1389         .proc_open      = nonseekable_open,
1390         .proc_write     = cio_settle_write,
1391         .proc_lseek     = no_llseek,
1392 };
1393
1394 static int __init cio_settle_init(void)
1395 {
1396         struct proc_dir_entry *entry;
1397
1398         entry = proc_create("cio_settle", S_IWUSR, NULL, &cio_settle_proc_ops);
1399         if (!entry)
1400                 return -ENOMEM;
1401         return 0;
1402 }
1403 device_initcall(cio_settle_init);
1404 #endif /*CONFIG_PROC_FS*/
1405
1406 int sch_is_pseudo_sch(struct subchannel *sch)
1407 {
1408         if (!sch->dev.parent)
1409                 return 0;
1410         return sch == to_css(sch->dev.parent)->pseudo_subchannel;
1411 }
1412
1413 static int css_bus_match(struct device *dev, struct device_driver *drv)
1414 {
1415         struct subchannel *sch = to_subchannel(dev);
1416         struct css_driver *driver = to_cssdriver(drv);
1417         struct css_device_id *id;
1418
1419         /* When driver_override is set, only bind to the matching driver */
1420         if (sch->driver_override && strcmp(sch->driver_override, drv->name))
1421                 return 0;
1422
1423         for (id = driver->subchannel_type; id->match_flags; id++) {
1424                 if (sch->st == id->type)
1425                         return 1;
1426         }
1427
1428         return 0;
1429 }
1430
1431 static int css_probe(struct device *dev)
1432 {
1433         struct subchannel *sch;
1434         int ret;
1435
1436         sch = to_subchannel(dev);
1437         sch->driver = to_cssdriver(dev->driver);
1438         ret = sch->driver->probe ? sch->driver->probe(sch) : 0;
1439         if (ret)
1440                 sch->driver = NULL;
1441         return ret;
1442 }
1443
1444 static int css_remove(struct device *dev)
1445 {
1446         struct subchannel *sch;
1447         int ret;
1448
1449         sch = to_subchannel(dev);
1450         ret = sch->driver->remove ? sch->driver->remove(sch) : 0;
1451         sch->driver = NULL;
1452         return ret;
1453 }
1454
1455 static void css_shutdown(struct device *dev)
1456 {
1457         struct subchannel *sch;
1458
1459         sch = to_subchannel(dev);
1460         if (sch->driver && sch->driver->shutdown)
1461                 sch->driver->shutdown(sch);
1462 }
1463
1464 static int css_uevent(struct device *dev, struct kobj_uevent_env *env)
1465 {
1466         struct subchannel *sch = to_subchannel(dev);
1467         int ret;
1468
1469         ret = add_uevent_var(env, "ST=%01X", sch->st);
1470         if (ret)
1471                 return ret;
1472         ret = add_uevent_var(env, "MODALIAS=css:t%01X", sch->st);
1473         return ret;
1474 }
1475
1476 static int css_pm_prepare(struct device *dev)
1477 {
1478         struct subchannel *sch = to_subchannel(dev);
1479         struct css_driver *drv;
1480
1481         if (mutex_is_locked(&sch->reg_mutex))
1482                 return -EAGAIN;
1483         if (!sch->dev.driver)
1484                 return 0;
1485         drv = to_cssdriver(sch->dev.driver);
1486         /* Notify drivers that they may not register children. */
1487         return drv->prepare ? drv->prepare(sch) : 0;
1488 }
1489
1490 static void css_pm_complete(struct device *dev)
1491 {
1492         struct subchannel *sch = to_subchannel(dev);
1493         struct css_driver *drv;
1494
1495         if (!sch->dev.driver)
1496                 return;
1497         drv = to_cssdriver(sch->dev.driver);
1498         if (drv->complete)
1499                 drv->complete(sch);
1500 }
1501
1502 static int css_pm_freeze(struct device *dev)
1503 {
1504         struct subchannel *sch = to_subchannel(dev);
1505         struct css_driver *drv;
1506
1507         if (!sch->dev.driver)
1508                 return 0;
1509         drv = to_cssdriver(sch->dev.driver);
1510         return drv->freeze ? drv->freeze(sch) : 0;
1511 }
1512
1513 static int css_pm_thaw(struct device *dev)
1514 {
1515         struct subchannel *sch = to_subchannel(dev);
1516         struct css_driver *drv;
1517
1518         if (!sch->dev.driver)
1519                 return 0;
1520         drv = to_cssdriver(sch->dev.driver);
1521         return drv->thaw ? drv->thaw(sch) : 0;
1522 }
1523
1524 static int css_pm_restore(struct device *dev)
1525 {
1526         struct subchannel *sch = to_subchannel(dev);
1527         struct css_driver *drv;
1528
1529         css_update_ssd_info(sch);
1530         if (!sch->dev.driver)
1531                 return 0;
1532         drv = to_cssdriver(sch->dev.driver);
1533         return drv->restore ? drv->restore(sch) : 0;
1534 }
1535
1536 static const struct dev_pm_ops css_pm_ops = {
1537         .prepare = css_pm_prepare,
1538         .complete = css_pm_complete,
1539         .freeze = css_pm_freeze,
1540         .thaw = css_pm_thaw,
1541         .restore = css_pm_restore,
1542 };
1543
1544 static struct bus_type css_bus_type = {
1545         .name     = "css",
1546         .match    = css_bus_match,
1547         .probe    = css_probe,
1548         .remove   = css_remove,
1549         .shutdown = css_shutdown,
1550         .uevent   = css_uevent,
1551         .pm = &css_pm_ops,
1552 };
1553
1554 /**
1555  * css_driver_register - register a css driver
1556  * @cdrv: css driver to register
1557  *
1558  * This is mainly a wrapper around driver_register that sets name
1559  * and bus_type in the embedded struct device_driver correctly.
1560  */
1561 int css_driver_register(struct css_driver *cdrv)
1562 {
1563         cdrv->drv.bus = &css_bus_type;
1564         return driver_register(&cdrv->drv);
1565 }
1566 EXPORT_SYMBOL_GPL(css_driver_register);
1567
1568 /**
1569  * css_driver_unregister - unregister a css driver
1570  * @cdrv: css driver to unregister
1571  *
1572  * This is a wrapper around driver_unregister.
1573  */
1574 void css_driver_unregister(struct css_driver *cdrv)
1575 {
1576         driver_unregister(&cdrv->drv);
1577 }
1578 EXPORT_SYMBOL_GPL(css_driver_unregister);