drivers/s390/cio/css.c

   1 /*
   2  * driver for channel subsystem
   3  *
   4  * Copyright IBM Corp. 2002, 2010
   5  *
   6  * Author(s): Arnd Bergmann (arndb@de.ibm.com)
   7  *            Cornelia Huck (cornelia.huck@de.ibm.com)
   8  *
   9  * License: GPL
  10  */
  11
  12 #define KMSG_COMPONENT "cio"
  13 #define pr_fmt(fmt) KMSG_COMPONENT ": " fmt
  14
  15 #include <linux/export.h>
  16 #include <linux/init.h>
  17 #include <linux/device.h>
  18 #include <linux/slab.h>
  19 #include <linux/errno.h>
  20 #include <linux/list.h>
  21 #include <linux/reboot.h>
  22 #include <linux/suspend.h>
  23 #include <linux/proc_fs.h>
  24 #include <asm/isc.h>
  25 #include <asm/crw.h>
  26
  27 #include "css.h"
  28 #include "cio.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 struct subchannel *css_alloc_subchannel(struct subchannel_id schid)
 173 {
 174         struct subchannel *sch;
 175         int ret;
 176
 177         sch = kzalloc(sizeof(*sch), GFP_KERNEL | GFP_DMA);
 178         if (!sch)
 179                 return ERR_PTR(-ENOMEM);
 180
 181         ret = cio_validate_subchannel(sch, schid);
 182         if (ret < 0)
 183                 goto err;
 184
 185         ret = css_sch_create_locks(sch);
 186         if (ret)
 187                 goto err;
 188
 189         INIT_WORK(&sch->todo_work, css_sch_todo);
 190         sch->dev.release = &css_subchannel_release;
 191         device_initialize(&sch->dev);
 192         return sch;
 193
 194 err:
 195         kfree(sch);
 196         return ERR_PTR(ret);
 197 }
 198
 199 static int css_sch_device_register(struct subchannel *sch)
 200 {
 201         int ret;
 202
 203         mutex_lock(&sch->reg_mutex);
 204         dev_set_name(&sch->dev, "0.%x.%04x", sch->schid.ssid,
 205                      sch->schid.sch_no);
 206         ret = device_add(&sch->dev);
 207         mutex_unlock(&sch->reg_mutex);
 208         return ret;
 209 }
 210
 211 /**
 212  * css_sch_device_unregister - unregister a subchannel
 213  * @sch: subchannel to be unregistered
 214  */
 215 void css_sch_device_unregister(struct subchannel *sch)
 216 {
 217         mutex_lock(&sch->reg_mutex);
 218         if (device_is_registered(&sch->dev))
 219                 device_unregister(&sch->dev);
 220         mutex_unlock(&sch->reg_mutex);
 221 }
 222 EXPORT_SYMBOL_GPL(css_sch_device_unregister);
 223
 224 static void ssd_from_pmcw(struct chsc_ssd_info *ssd, struct pmcw *pmcw)
 225 {
 226         int i;
 227         int mask;
 228
 229         memset(ssd, 0, sizeof(struct chsc_ssd_info));
 230         ssd->path_mask = pmcw->pim;
 231         for (i = 0; i < 8; i++) {
 232                 mask = 0x80 >> i;
 233                 if (pmcw->pim & mask) {
 234                         chp_id_init(&ssd->chpid[i]);
 235                         ssd->chpid[i].id = pmcw->chpid[i];
 236                 }
 237         }
 238 }
 239
 240 static void ssd_register_chpids(struct chsc_ssd_info *ssd)
 241 {
 242         int i;
 243         int mask;
 244
 245         for (i = 0; i < 8; i++) {
 246                 mask = 0x80 >> i;
 247                 if (ssd->path_mask & mask)
 248                         if (!chp_is_registered(ssd->chpid[i]))
 249                                 chp_new(ssd->chpid[i]);
 250         }
 251 }
 252
 253 void css_update_ssd_info(struct subchannel *sch)
 254 {
 255         int ret;
 256
 257         ret = chsc_get_ssd_info(sch->schid, &sch->ssd_info);
 258         if (ret)
 259                 ssd_from_pmcw(&sch->ssd_info, &sch->schib.pmcw);
 260
 261         ssd_register_chpids(&sch->ssd_info);
 262 }
 263
 264 static ssize_t type_show(struct device *dev, struct device_attribute *attr,
 265                          char *buf)
 266 {
 267         struct subchannel *sch = to_subchannel(dev);
 268
 269         return sprintf(buf, "%01x\n", sch->st);
 270 }
 271
 272 static DEVICE_ATTR(type, 0444, type_show, NULL);
 273
 274 static ssize_t modalias_show(struct device *dev, struct device_attribute *attr,
 275                              char *buf)
 276 {
 277         struct subchannel *sch = to_subchannel(dev);
 278
 279         return sprintf(buf, "css:t%01X\n", sch->st);
 280 }
 281
 282 static DEVICE_ATTR(modalias, 0444, modalias_show, NULL);
 283
 284 static struct attribute *subch_attrs[] = {
 285         &dev_attr_type.attr,
 286         &dev_attr_modalias.attr,
 287         NULL,
 288 };
 289
 290 static struct attribute_group subch_attr_group = {
 291         .attrs = subch_attrs,
 292 };
 293
 294 static const struct attribute_group *default_subch_attr_groups[] = {
 295         &subch_attr_group,
 296         NULL,
 297 };
 298
 299 static ssize_t chpids_show(struct device *dev,
 300                            struct device_attribute *attr,
 301                            char *buf)
 302 {
 303         struct subchannel *sch = to_subchannel(dev);
 304         struct chsc_ssd_info *ssd = &sch->ssd_info;
 305         ssize_t ret = 0;
 306         int mask;
 307         int chp;
 308
 309         for (chp = 0; chp < 8; chp++) {
 310                 mask = 0x80 >> chp;
 311                 if (ssd->path_mask & mask)
 312                         ret += sprintf(buf + ret, "%02x ", ssd->chpid[chp].id);
 313                 else
 314                         ret += sprintf(buf + ret, "00 ");
 315         }
 316         ret += sprintf(buf + ret, "\n");
 317         return ret;
 318 }
 319 static DEVICE_ATTR(chpids, 0444, chpids_show, NULL);
 320
 321 static ssize_t pimpampom_show(struct device *dev,
 322                               struct device_attribute *attr,
 323                               char *buf)
 324 {
 325         struct subchannel *sch = to_subchannel(dev);
 326         struct pmcw *pmcw = &sch->schib.pmcw;
 327
 328         return sprintf(buf, "%02x %02x %02x\n",
 329                        pmcw->pim, pmcw->pam, pmcw->pom);
 330 }
 331 static DEVICE_ATTR(pimpampom, 0444, pimpampom_show, NULL);
 332
 333 static ssize_t dev_busid_show(struct device *dev,
 334                               struct device_attribute *attr,
 335                               char *buf)
 336 {
 337         struct subchannel *sch = to_subchannel(dev);
 338         struct pmcw *pmcw = &sch->schib.pmcw;
 339
 340         if ((pmcw->st == SUBCHANNEL_TYPE_IO && pmcw->dnv) ||
 341             (pmcw->st == SUBCHANNEL_TYPE_MSG && pmcw->w))
 342                 return sysfs_emit(buf, "0.%x.%04x\n", sch->schid.ssid,
 343                                   pmcw->dev);
 344         else
 345                 return sysfs_emit(buf, "none\n");
 346 }
 347 static DEVICE_ATTR_RO(dev_busid);
 348
 349 static struct attribute *io_subchannel_type_attrs[] = {
 350         &dev_attr_chpids.attr,
 351         &dev_attr_pimpampom.attr,
 352         &dev_attr_dev_busid.attr,
 353         NULL,
 354 };
 355 ATTRIBUTE_GROUPS(io_subchannel_type);
 356
 357 static const struct device_type io_subchannel_type = {
 358         .groups = io_subchannel_type_groups,
 359 };
 360
 361 int css_register_subchannel(struct subchannel *sch)
 362 {
 363         int ret;
 364
 365         /* Initialize the subchannel structure */
 366         sch->dev.parent = &channel_subsystems[0]->device;
 367         sch->dev.bus = &css_bus_type;
 368         sch->dev.groups = default_subch_attr_groups;
 369
 370         if (sch->st == SUBCHANNEL_TYPE_IO)
 371                 sch->dev.type = &io_subchannel_type;
 372
 373         /*
 374          * We don't want to generate uevents for I/O subchannels that don't
 375          * have a working ccw device behind them since they will be
 376          * unregistered before they can be used anyway, so we delay the add
 377          * uevent until after device recognition was successful.
 378          * Note that we suppress the uevent for all subchannel types;
 379          * the subchannel driver can decide itself when it wants to inform
 380          * userspace of its existence.
 381          */
 382         dev_set_uevent_suppress(&sch->dev, 1);
 383         css_update_ssd_info(sch);
 384         /* make it known to the system */
 385         ret = css_sch_device_register(sch);
 386         if (ret) {
 387                 CIO_MSG_EVENT(0, "Could not register sch 0.%x.%04x: %d\n",
 388                               sch->schid.ssid, sch->schid.sch_no, ret);
 389                 return ret;
 390         }
 391         if (!sch->driver) {
 392                 /*
 393                  * No driver matched. Generate the uevent now so that
 394                  * a fitting driver module may be loaded based on the
 395                  * modalias.
 396                  */
 397                 dev_set_uevent_suppress(&sch->dev, 0);
 398                 kobject_uevent(&sch->dev.kobj, KOBJ_ADD);
 399         }
 400         return ret;
 401 }
 402
 403 static int css_probe_device(struct subchannel_id schid)
 404 {
 405         struct subchannel *sch;
 406         int ret;
 407
 408         sch = css_alloc_subchannel(schid);
 409         if (IS_ERR(sch))
 410                 return PTR_ERR(sch);
 411
 412         ret = css_register_subchannel(sch);
 413         if (ret)
 414                 put_device(&sch->dev);
 415
 416         return ret;
 417 }
 418
 419 static int
 420 check_subchannel(struct device * dev, void * data)
 421 {
 422         struct subchannel *sch;
 423         struct subchannel_id *schid = data;
 424
 425         sch = to_subchannel(dev);
 426         return schid_equal(&sch->schid, schid);
 427 }
 428
 429 struct subchannel *
 430 get_subchannel_by_schid(struct subchannel_id schid)
 431 {
 432         struct device *dev;
 433
 434         dev = bus_find_device(&css_bus_type, NULL,
 435                               &schid, check_subchannel);
 436
 437         return dev ? to_subchannel(dev) : NULL;
 438 }
 439
 440 /**
 441  * css_sch_is_valid() - check if a subchannel is valid
 442  * @schib: subchannel information block for the subchannel
 443  */
 444 int css_sch_is_valid(struct schib *schib)
 445 {
 446         if ((schib->pmcw.st == SUBCHANNEL_TYPE_IO) && !schib->pmcw.dnv)
 447                 return 0;
 448         if ((schib->pmcw.st == SUBCHANNEL_TYPE_MSG) && !schib->pmcw.w)
 449                 return 0;
 450         return 1;
 451 }
 452 EXPORT_SYMBOL_GPL(css_sch_is_valid);
 453
 454 static int css_evaluate_new_subchannel(struct subchannel_id schid, int slow)
 455 {
 456         struct schib schib;
 457
 458         if (!slow) {
 459                 /* Will be done on the slow path. */
 460                 return -EAGAIN;
 461         }
 462         if (stsch(schid, &schib)) {
 463                 /* Subchannel is not provided. */
 464                 return -ENXIO;
 465         }
 466         if (!css_sch_is_valid(&schib)) {
 467                 /* Unusable - ignore. */
 468                 return 0;
 469         }
 470         CIO_MSG_EVENT(4, "event: sch 0.%x.%04x, new\n", schid.ssid,
 471                       schid.sch_no);
 472
 473         return css_probe_device(schid);
 474 }
 475
 476 static int css_evaluate_known_subchannel(struct subchannel *sch, int slow)
 477 {
 478         int ret = 0;
 479
 480         if (sch->driver) {
 481                 if (sch->driver->sch_event)
 482                         ret = sch->driver->sch_event(sch, slow);
 483                 else
 484                         dev_dbg(&sch->dev,
 485                                 "Got subchannel machine check but "
 486                                 "no sch_event handler provided.\n");
 487         }
 488         if (ret != 0 && ret != -EAGAIN) {
 489                 CIO_MSG_EVENT(2, "eval: sch 0.%x.%04x, rc=%d\n",
 490                               sch->schid.ssid, sch->schid.sch_no, ret);
 491         }
 492         return ret;
 493 }
 494
 495 static void css_evaluate_subchannel(struct subchannel_id schid, int slow)
 496 {
 497         struct subchannel *sch;
 498         int ret;
 499
 500         sch = get_subchannel_by_schid(schid);
 501         if (sch) {
 502                 ret = css_evaluate_known_subchannel(sch, slow);
 503                 put_device(&sch->dev);
 504         } else
 505                 ret = css_evaluate_new_subchannel(schid, slow);
 506         if (ret == -EAGAIN)
 507                 css_schedule_eval(schid);
 508 }
 509
 510 /**
 511  * css_sched_sch_todo - schedule a subchannel operation
 512  * @sch: subchannel
 513  * @todo: todo
 514  *
 515  * Schedule the operation identified by @todo to be performed on the slow path
 516  * workqueue. Do nothing if another operation with higher priority is already
 517  * scheduled. Needs to be called with subchannel lock held.
 518  */
 519 void css_sched_sch_todo(struct subchannel *sch, enum sch_todo todo)
 520 {
 521         CIO_MSG_EVENT(4, "sch_todo: sched sch=0.%x.%04x todo=%d\n",
 522                       sch->schid.ssid, sch->schid.sch_no, todo);
 523         if (sch->todo >= todo)
 524                 return;
 525         /* Get workqueue ref. */
 526         if (!get_device(&sch->dev))
 527                 return;
 528         sch->todo = todo;
 529         if (!queue_work(cio_work_q, &sch->todo_work)) {
 530                 /* Already queued, release workqueue ref. */
 531                 put_device(&sch->dev);
 532         }
 533 }
 534 EXPORT_SYMBOL_GPL(css_sched_sch_todo);
 535
 536 static void css_sch_todo(struct work_struct *work)
 537 {
 538         struct subchannel *sch;
 539         enum sch_todo todo;
 540         int ret;
 541
 542         sch = container_of(work, struct subchannel, todo_work);
 543         /* Find out todo. */
 544         spin_lock_irq(sch->lock);
 545         todo = sch->todo;
 546         CIO_MSG_EVENT(4, "sch_todo: sch=0.%x.%04x, todo=%d\n", sch->schid.ssid,
 547                       sch->schid.sch_no, todo);
 548         sch->todo = SCH_TODO_NOTHING;
 549         spin_unlock_irq(sch->lock);
 550         /* Perform todo. */
 551         switch (todo) {
 552         case SCH_TODO_NOTHING:
 553                 break;
 554         case SCH_TODO_EVAL:
 555                 ret = css_evaluate_known_subchannel(sch, 1);
 556                 if (ret == -EAGAIN) {
 557                         spin_lock_irq(sch->lock);
 558                         css_sched_sch_todo(sch, todo);
 559                         spin_unlock_irq(sch->lock);
 560                 }
 561                 break;
 562         case SCH_TODO_UNREG:
 563                 css_sch_device_unregister(sch);
 564                 break;
 565         }
 566         /* Release workqueue ref. */
 567         put_device(&sch->dev);
 568 }
 569
 570 static struct idset *slow_subchannel_set;
 571 static spinlock_t slow_subchannel_lock;
 572 static wait_queue_head_t css_eval_wq;
 573 static atomic_t css_eval_scheduled;
 574
 575 static int __init slow_subchannel_init(void)
 576 {
 577         spin_lock_init(&slow_subchannel_lock);
 578         atomic_set(&css_eval_scheduled, 0);
 579         init_waitqueue_head(&css_eval_wq);
 580         slow_subchannel_set = idset_sch_new();
 581         if (!slow_subchannel_set) {
 582                 CIO_MSG_EVENT(0, "could not allocate slow subchannel set\n");
 583                 return -ENOMEM;
 584         }
 585         return 0;
 586 }
 587
 588 static int slow_eval_known_fn(struct subchannel *sch, void *data)
 589 {
 590         int eval;
 591         int rc;
 592
 593         spin_lock_irq(&slow_subchannel_lock);
 594         eval = idset_sch_contains(slow_subchannel_set, sch->schid);
 595         idset_sch_del(slow_subchannel_set, sch->schid);
 596         spin_unlock_irq(&slow_subchannel_lock);
 597         if (eval) {
 598                 rc = css_evaluate_known_subchannel(sch, 1);
 599                 if (rc == -EAGAIN)
 600                         css_schedule_eval(sch->schid);
 601                 /*
 602                  * The loop might take long time for platforms with lots of
 603                  * known devices. Allow scheduling here.
 604                  */
 605                 cond_resched();
 606         }
 607         return 0;
 608 }
 609
 610 static int slow_eval_unknown_fn(struct subchannel_id schid, void *data)
 611 {
 612         int eval;
 613         int rc = 0;
 614
 615         spin_lock_irq(&slow_subchannel_lock);
 616         eval = idset_sch_contains(slow_subchannel_set, schid);
 617         idset_sch_del(slow_subchannel_set, schid);
 618         spin_unlock_irq(&slow_subchannel_lock);
 619         if (eval) {
 620                 rc = css_evaluate_new_subchannel(schid, 1);
 621                 switch (rc) {
 622                 case -EAGAIN:
 623                         css_schedule_eval(schid);
 624                         rc = 0;
 625                         break;
 626                 case -ENXIO:
 627                 case -ENOMEM:
 628                 case -EIO:
 629                         /* These should abort looping */
 630                         spin_lock_irq(&slow_subchannel_lock);
 631                         idset_sch_del_subseq(slow_subchannel_set, schid);
 632                         spin_unlock_irq(&slow_subchannel_lock);
 633                         break;
 634                 default:
 635                         rc = 0;
 636                 }
 637                 /* Allow scheduling here since the containing loop might
 638                  * take a while.  */
 639                 cond_resched();
 640         }
 641         return rc;
 642 }
 643
 644 static void css_slow_path_func(struct work_struct *unused)
 645 {
 646         unsigned long flags;
 647
 648         CIO_TRACE_EVENT(4, "slowpath");
 649         for_each_subchannel_staged(slow_eval_known_fn, slow_eval_unknown_fn,
 650                                    NULL);
 651         spin_lock_irqsave(&slow_subchannel_lock, flags);
 652         if (idset_is_empty(slow_subchannel_set)) {
 653                 atomic_set(&css_eval_scheduled, 0);
 654                 wake_up(&css_eval_wq);
 655         }
 656         spin_unlock_irqrestore(&slow_subchannel_lock, flags);
 657 }
 658
 659 static DECLARE_DELAYED_WORK(slow_path_work, css_slow_path_func);
 660 struct workqueue_struct *cio_work_q;
 661
 662 void css_schedule_eval(struct subchannel_id schid)
 663 {
 664         unsigned long flags;
 665
 666         spin_lock_irqsave(&slow_subchannel_lock, flags);
 667         idset_sch_add(slow_subchannel_set, schid);
 668         atomic_set(&css_eval_scheduled, 1);
 669         queue_delayed_work(cio_work_q, &slow_path_work, 0);
 670         spin_unlock_irqrestore(&slow_subchannel_lock, flags);
 671 }
 672
 673 void css_schedule_eval_all(void)
 674 {
 675         unsigned long flags;
 676
 677         spin_lock_irqsave(&slow_subchannel_lock, flags);
 678         idset_fill(slow_subchannel_set);
 679         atomic_set(&css_eval_scheduled, 1);
 680         queue_delayed_work(cio_work_q, &slow_path_work, 0);
 681         spin_unlock_irqrestore(&slow_subchannel_lock, flags);
 682 }
 683
 684 static int __unset_registered(struct device *dev, void *data)
 685 {
 686         struct idset *set = data;
 687         struct subchannel *sch = to_subchannel(dev);
 688
 689         idset_sch_del(set, sch->schid);
 690         return 0;
 691 }
 692
 693 void css_schedule_eval_all_unreg(unsigned long delay)
 694 {
 695         unsigned long flags;
 696         struct idset *unreg_set;
 697
 698         /* Find unregistered subchannels. */
 699         unreg_set = idset_sch_new();
 700         if (!unreg_set) {
 701                 /* Fallback. */
 702                 css_schedule_eval_all();
 703                 return;
 704         }
 705         idset_fill(unreg_set);
 706         bus_for_each_dev(&css_bus_type, NULL, unreg_set, __unset_registered);
 707         /* Apply to slow_subchannel_set. */
 708         spin_lock_irqsave(&slow_subchannel_lock, flags);
 709         idset_add_set(slow_subchannel_set, unreg_set);
 710         atomic_set(&css_eval_scheduled, 1);
 711         queue_delayed_work(cio_work_q, &slow_path_work, delay);
 712         spin_unlock_irqrestore(&slow_subchannel_lock, flags);
 713         idset_free(unreg_set);
 714 }
 715
 716 void css_wait_for_slow_path(void)
 717 {
 718         flush_workqueue(cio_work_q);
 719 }
 720
 721 /* Schedule reprobing of all unregistered subchannels. */
 722 void css_schedule_reprobe(void)
 723 {
 724         /* Schedule with a delay to allow merging of subsequent calls. */
 725         css_schedule_eval_all_unreg(1 * HZ);
 726 }
 727 EXPORT_SYMBOL_GPL(css_schedule_reprobe);
 728
 729 /*
 730  * Called from the machine check handler for subchannel report words.
 731  */
 732 static void css_process_crw(struct crw *crw0, struct crw *crw1, int overflow)
 733 {
 734         struct subchannel_id mchk_schid;
 735         struct subchannel *sch;
 736
 737         if (overflow) {
 738                 css_schedule_eval_all();
 739                 return;
 740         }
 741         CIO_CRW_EVENT(2, "CRW0 reports slct=%d, oflw=%d, "
 742                       "chn=%d, rsc=%X, anc=%d, erc=%X, rsid=%X\n",
 743                       crw0->slct, crw0->oflw, crw0->chn, crw0->rsc, crw0->anc,
 744                       crw0->erc, crw0->rsid);
 745         if (crw1)
 746                 CIO_CRW_EVENT(2, "CRW1 reports slct=%d, oflw=%d, "
 747                               "chn=%d, rsc=%X, anc=%d, erc=%X, rsid=%X\n",
 748                               crw1->slct, crw1->oflw, crw1->chn, crw1->rsc,
 749                               crw1->anc, crw1->erc, crw1->rsid);
 750         init_subchannel_id(&mchk_schid);
 751         mchk_schid.sch_no = crw0->rsid;
 752         if (crw1)
 753                 mchk_schid.ssid = (crw1->rsid >> 4) & 3;
 754
 755         if (crw0->erc == CRW_ERC_PMOD) {
 756                 sch = get_subchannel_by_schid(mchk_schid);
 757                 if (sch) {
 758                         css_update_ssd_info(sch);
 759                         put_device(&sch->dev);
 760                 }
 761         }
 762         /*
 763          * Since we are always presented with IPI in the CRW, we have to
 764          * use stsch() to find out if the subchannel in question has come
 765          * or gone.
 766          */
 767         css_evaluate_subchannel(mchk_schid, 0);
 768 }
 769
 770 static void __init
 771 css_generate_pgid(struct channel_subsystem *css, u32 tod_high)
 772 {
 773         struct cpuid cpu_id;
 774
 775         if (css_general_characteristics.mcss) {
 776                 css->global_pgid.pgid_high.ext_cssid.version = 0x80;
 777                 css->global_pgid.pgid_high.ext_cssid.cssid =
 778                         (css->cssid < 0) ? 0 : css->cssid;
 779         } else {
 780                 css->global_pgid.pgid_high.cpu_addr = stap();
 781         }
 782         get_cpu_id(&cpu_id);
 783         css->global_pgid.cpu_id = cpu_id.ident;
 784         css->global_pgid.cpu_model = cpu_id.machine;
 785         css->global_pgid.tod_high = tod_high;
 786 }
 787
 788 static void channel_subsystem_release(struct device *dev)
 789 {
 790         struct channel_subsystem *css = to_css(dev);
 791
 792         mutex_destroy(&css->mutex);
 793         kfree(css);
 794 }
 795
 796 static ssize_t real_cssid_show(struct device *dev, struct device_attribute *a,
 797                                char *buf)
 798 {
 799         struct channel_subsystem *css = to_css(dev);
 800
 801         if (css->cssid < 0)
 802                 return -EINVAL;
 803
 804         return sprintf(buf, "%x\n", css->cssid);
 805 }
 806 static DEVICE_ATTR_RO(real_cssid);
 807
 808 static ssize_t cm_enable_show(struct device *dev, struct device_attribute *a,
 809                               char *buf)
 810 {
 811         struct channel_subsystem *css = to_css(dev);
 812         int ret;
 813
 814         mutex_lock(&css->mutex);
 815         ret = sprintf(buf, "%x\n", css->cm_enabled);
 816         mutex_unlock(&css->mutex);
 817         return ret;
 818 }
 819
 820 static ssize_t cm_enable_store(struct device *dev, struct device_attribute *a,
 821                                const char *buf, size_t count)
 822 {
 823         struct channel_subsystem *css = to_css(dev);
 824         unsigned long val;
 825         int ret;
 826
 827         ret = kstrtoul(buf, 16, &val);
 828         if (ret)
 829                 return ret;
 830         mutex_lock(&css->mutex);
 831         switch (val) {
 832         case 0:
 833                 ret = css->cm_enabled ? chsc_secm(css, 0) : 0;
 834                 break;
 835         case 1:
 836                 ret = css->cm_enabled ? 0 : chsc_secm(css, 1);
 837                 break;
 838         default:
 839                 ret = -EINVAL;
 840         }
 841         mutex_unlock(&css->mutex);
 842         return ret < 0 ? ret : count;
 843 }
 844 static DEVICE_ATTR_RW(cm_enable);
 845
 846 static umode_t cm_enable_mode(struct kobject *kobj, struct attribute *attr,
 847                               int index)
 848 {
 849         return css_chsc_characteristics.secm ? attr->mode : 0;
 850 }
 851
 852 static struct attribute *cssdev_attrs[] = {
 853         &dev_attr_real_cssid.attr,
 854         NULL,
 855 };
 856
 857 static struct attribute_group cssdev_attr_group = {
 858         .attrs = cssdev_attrs,
 859 };
 860
 861 static struct attribute *cssdev_cm_attrs[] = {
 862         &dev_attr_cm_enable.attr,
 863         NULL,
 864 };
 865
 866 static struct attribute_group cssdev_cm_attr_group = {
 867         .attrs = cssdev_cm_attrs,
 868         .is_visible = cm_enable_mode,
 869 };
 870
 871 static const struct attribute_group *cssdev_attr_groups[] = {
 872         &cssdev_attr_group,
 873         &cssdev_cm_attr_group,
 874         NULL,
 875 };
 876
 877 static int __init setup_css(int nr)
 878 {
 879         struct channel_subsystem *css;
 880         int ret;
 881
 882         css = kzalloc(sizeof(*css), GFP_KERNEL);
 883         if (!css)
 884                 return -ENOMEM;
 885
 886         channel_subsystems[nr] = css;
 887         dev_set_name(&css->device, "css%x", nr);
 888         css->device.groups = cssdev_attr_groups;
 889         css->device.release = channel_subsystem_release;
 890
 891         mutex_init(&css->mutex);
 892         css->cssid = chsc_get_cssid(nr);
 893         css_generate_pgid(css, (u32) (get_tod_clock() >> 32));
 894
 895         ret = device_register(&css->device);
 896         if (ret) {
 897                 put_device(&css->device);
 898                 goto out_err;
 899         }
 900
 901         css->pseudo_subchannel = kzalloc(sizeof(*css->pseudo_subchannel),
 902                                          GFP_KERNEL);
 903         if (!css->pseudo_subchannel) {
 904                 device_unregister(&css->device);
 905                 ret = -ENOMEM;
 906                 goto out_err;
 907         }
 908
 909         css->pseudo_subchannel->dev.parent = &css->device;
 910         css->pseudo_subchannel->dev.release = css_subchannel_release;
 911         mutex_init(&css->pseudo_subchannel->reg_mutex);
 912         ret = css_sch_create_locks(css->pseudo_subchannel);
 913         if (ret) {
 914                 kfree(css->pseudo_subchannel);
 915                 device_unregister(&css->device);
 916                 goto out_err;
 917         }
 918
 919         dev_set_name(&css->pseudo_subchannel->dev, "defunct");
 920         ret = device_register(&css->pseudo_subchannel->dev);
 921         if (ret) {
 922                 put_device(&css->pseudo_subchannel->dev);
 923                 device_unregister(&css->device);
 924                 goto out_err;
 925         }
 926
 927         return ret;
 928 out_err:
 929         channel_subsystems[nr] = NULL;
 930         return ret;
 931 }
 932
 933 static int css_reboot_event(struct notifier_block *this,
 934                             unsigned long event,
 935                             void *ptr)
 936 {
 937         struct channel_subsystem *css;
 938         int ret;
 939
 940         ret = NOTIFY_DONE;
 941         for_each_css(css) {
 942                 mutex_lock(&css->mutex);
 943                 if (css->cm_enabled)
 944                         if (chsc_secm(css, 0))
 945                                 ret = NOTIFY_BAD;
 946                 mutex_unlock(&css->mutex);
 947         }
 948
 949         return ret;
 950 }
 951
 952 static struct notifier_block css_reboot_notifier = {
 953         .notifier_call = css_reboot_event,
 954 };
 955
 956 /*
 957  * Since the css devices are neither on a bus nor have a class
 958  * nor have a special device type, we cannot stop/restart channel
 959  * path measurements via the normal suspend/resume callbacks, but have
 960  * to use notifiers.
 961  */
 962 static int css_power_event(struct notifier_block *this, unsigned long event,
 963                            void *ptr)
 964 {
 965         struct channel_subsystem *css;
 966         int ret;
 967
 968         switch (event) {
 969         case PM_HIBERNATION_PREPARE:
 970         case PM_SUSPEND_PREPARE:
 971                 ret = NOTIFY_DONE;
 972                 for_each_css(css) {
 973                         mutex_lock(&css->mutex);
 974                         if (!css->cm_enabled) {
 975                                 mutex_unlock(&css->mutex);
 976                                 continue;
 977                         }
 978                         ret = __chsc_do_secm(css, 0);
 979                         ret = notifier_from_errno(ret);
 980                         mutex_unlock(&css->mutex);
 981                 }
 982                 break;
 983         case PM_POST_HIBERNATION:
 984         case PM_POST_SUSPEND:
 985                 ret = NOTIFY_DONE;
 986                 for_each_css(css) {
 987                         mutex_lock(&css->mutex);
 988                         if (!css->cm_enabled) {
 989                                 mutex_unlock(&css->mutex);
 990                                 continue;
 991                         }
 992                         ret = __chsc_do_secm(css, 1);
 993                         ret = notifier_from_errno(ret);
 994                         mutex_unlock(&css->mutex);
 995                 }
 996                 /* search for subchannels, which appeared during hibernation */
 997                 css_schedule_reprobe();
 998                 break;
 999         default:
1000                 ret = NOTIFY_DONE;
1001         }
1002         return ret;
1003
1004 }
1005 static struct notifier_block css_power_notifier = {
1006         .notifier_call = css_power_event,
1007 };
1008
1009 /*
1010  * Now that the driver core is running, we can setup our channel subsystem.
1011  * The struct subchannel's are created during probing.
1012  */
1013 static int __init css_bus_init(void)
1014 {
1015         int ret, i;
1016
1017         ret = chsc_init();
1018         if (ret)
1019                 return ret;
1020
1021         chsc_determine_css_characteristics();
1022         /* Try to enable MSS. */
1023         ret = chsc_enable_facility(CHSC_SDA_OC_MSS);
1024         if (ret)
1025                 max_ssid = 0;
1026         else /* Success. */
1027                 max_ssid = __MAX_SSID;
1028
1029         ret = slow_subchannel_init();
1030         if (ret)
1031                 goto out;
1032
1033         ret = crw_register_handler(CRW_RSC_SCH, css_process_crw);
1034         if (ret)
1035                 goto out;
1036
1037         if ((ret = bus_register(&css_bus_type)))
1038                 goto out;
1039
1040         /* Setup css structure. */
1041         for (i = 0; i <= MAX_CSS_IDX; i++) {
1042                 ret = setup_css(i);
1043                 if (ret)
1044                         goto out_unregister;
1045         }
1046         ret = register_reboot_notifier(&css_reboot_notifier);
1047         if (ret)
1048                 goto out_unregister;
1049         ret = register_pm_notifier(&css_power_notifier);
1050         if (ret) {
1051                 unregister_reboot_notifier(&css_reboot_notifier);
1052                 goto out_unregister;
1053         }
1054         css_init_done = 1;
1055
1056         /* Enable default isc for I/O subchannels. */
1057         isc_register(IO_SCH_ISC);
1058
1059         return 0;
1060 out_unregister:
1061         while (i-- > 0) {
1062                 struct channel_subsystem *css = channel_subsystems[i];
1063                 device_unregister(&css->pseudo_subchannel->dev);
1064                 device_unregister(&css->device);
1065         }
1066         bus_unregister(&css_bus_type);
1067 out:
1068         crw_unregister_handler(CRW_RSC_SCH);
1069         idset_free(slow_subchannel_set);
1070         chsc_init_cleanup();
1071         pr_alert("The CSS device driver initialization failed with "
1072                  "errno=%d\n", ret);
1073         return ret;
1074 }
1075
1076 static void __init css_bus_cleanup(void)
1077 {
1078         struct channel_subsystem *css;
1079
1080         for_each_css(css) {
1081                 device_unregister(&css->pseudo_subchannel->dev);
1082                 device_unregister(&css->device);
1083         }
1084         bus_unregister(&css_bus_type);
1085         crw_unregister_handler(CRW_RSC_SCH);
1086         idset_free(slow_subchannel_set);
1087         chsc_init_cleanup();
1088         isc_unregister(IO_SCH_ISC);
1089 }
1090
1091 static int __init channel_subsystem_init(void)
1092 {
1093         int ret;
1094
1095         ret = css_bus_init();
1096         if (ret)
1097                 return ret;
1098         cio_work_q = create_singlethread_workqueue("cio");
1099         if (!cio_work_q) {
1100                 ret = -ENOMEM;
1101                 goto out_bus;
1102         }
1103         ret = io_subchannel_init();
1104         if (ret)
1105                 goto out_wq;
1106
1107         return ret;
1108 out_wq:
1109         destroy_workqueue(cio_work_q);
1110 out_bus:
1111         css_bus_cleanup();
1112         return ret;
1113 }
1114 subsys_initcall(channel_subsystem_init);
1115
1116 static int css_settle(struct device_driver *drv, void *unused)
1117 {
1118         struct css_driver *cssdrv = to_cssdriver(drv);
1119
1120         if (cssdrv->settle)
1121                 return cssdrv->settle();
1122         return 0;
1123 }
1124
1125 int css_complete_work(void)
1126 {
1127         int ret;
1128
1129         /* Wait for the evaluation of subchannels to finish. */
1130         ret = wait_event_interruptible(css_eval_wq,
1131                                        atomic_read(&css_eval_scheduled) == 0);
1132         if (ret)
1133                 return -EINTR;
1134         flush_workqueue(cio_work_q);
1135         /* Wait for the subchannel type specific initialization to finish */
1136         return bus_for_each_drv(&css_bus_type, NULL, NULL, css_settle);
1137 }
1138
1139
1140 /*
1141  * Wait for the initialization of devices to finish, to make sure we are
1142  * done with our setup if the search for the root device starts.
1143  */
1144 static int __init channel_subsystem_init_sync(void)
1145 {
1146         /* Register subchannels which are already in use. */
1147         cio_register_early_subchannels();
1148         /* Start initial subchannel evaluation. */
1149         css_schedule_eval_all();
1150         css_complete_work();
1151         return 0;
1152 }
1153 subsys_initcall_sync(channel_subsystem_init_sync);
1154
1155 void channel_subsystem_reinit(void)
1156 {
1157         struct channel_path *chp;
1158         struct chp_id chpid;
1159
1160         chsc_enable_facility(CHSC_SDA_OC_MSS);
1161         chp_id_for_each(&chpid) {
1162                 chp = chpid_to_chp(chpid);
1163                 if (chp)
1164                         chp_update_desc(chp);
1165         }
1166         cmf_reactivate();
1167 }
1168
1169 #ifdef CONFIG_PROC_FS
1170 static ssize_t cio_settle_write(struct file *file, const char __user *buf,
1171                                 size_t count, loff_t *ppos)
1172 {
1173         int ret;
1174
1175         /* Handle pending CRW's. */
1176         crw_wait_for_channel_report();
1177         ret = css_complete_work();
1178
1179         return ret ? ret : count;
1180 }
1181
1182 static const struct file_operations cio_settle_proc_fops = {
1183         .open = nonseekable_open,
1184         .write = cio_settle_write,
1185         .llseek = no_llseek,
1186 };
1187
1188 static int __init cio_settle_init(void)
1189 {
1190         struct proc_dir_entry *entry;
1191
1192         entry = proc_create("cio_settle", S_IWUSR, NULL,
1193                             &cio_settle_proc_fops);
1194         if (!entry)
1195                 return -ENOMEM;
1196         return 0;
1197 }
1198 device_initcall(cio_settle_init);
1199 #endif /*CONFIG_PROC_FS*/
1200
1201 int sch_is_pseudo_sch(struct subchannel *sch)
1202 {
1203         if (!sch->dev.parent)
1204                 return 0;
1205         return sch == to_css(sch->dev.parent)->pseudo_subchannel;
1206 }
1207
1208 static int css_bus_match(struct device *dev, struct device_driver *drv)
1209 {
1210         struct subchannel *sch = to_subchannel(dev);
1211         struct css_driver *driver = to_cssdriver(drv);
1212         struct css_device_id *id;
1213
1214         for (id = driver->subchannel_type; id->match_flags; id++) {
1215                 if (sch->st == id->type)
1216                         return 1;
1217         }
1218
1219         return 0;
1220 }
1221
1222 static int css_probe(struct device *dev)
1223 {
1224         struct subchannel *sch;
1225         int ret;
1226
1227         sch = to_subchannel(dev);
1228         sch->driver = to_cssdriver(dev->driver);
1229         ret = sch->driver->probe ? sch->driver->probe(sch) : 0;
1230         if (ret)
1231                 sch->driver = NULL;
1232         return ret;
1233 }
1234
1235 static int css_remove(struct device *dev)
1236 {
1237         struct subchannel *sch;
1238         int ret;
1239
1240         sch = to_subchannel(dev);
1241         ret = sch->driver->remove ? sch->driver->remove(sch) : 0;
1242         sch->driver = NULL;
1243         return ret;
1244 }
1245
1246 static void css_shutdown(struct device *dev)
1247 {
1248         struct subchannel *sch;
1249
1250         sch = to_subchannel(dev);
1251         if (sch->driver && sch->driver->shutdown)
1252                 sch->driver->shutdown(sch);
1253 }
1254
1255 static int css_uevent(struct device *dev, struct kobj_uevent_env *env)
1256 {
1257         struct subchannel *sch = to_subchannel(dev);
1258         int ret;
1259
1260         ret = add_uevent_var(env, "ST=%01X", sch->st);
1261         if (ret)
1262                 return ret;
1263         ret = add_uevent_var(env, "MODALIAS=css:t%01X", sch->st);
1264         return ret;
1265 }
1266
1267 static int css_pm_prepare(struct device *dev)
1268 {
1269         struct subchannel *sch = to_subchannel(dev);
1270         struct css_driver *drv;
1271
1272         if (mutex_is_locked(&sch->reg_mutex))
1273                 return -EAGAIN;
1274         if (!sch->dev.driver)
1275                 return 0;
1276         drv = to_cssdriver(sch->dev.driver);
1277         /* Notify drivers that they may not register children. */
1278         return drv->prepare ? drv->prepare(sch) : 0;
1279 }
1280
1281 static void css_pm_complete(struct device *dev)
1282 {
1283         struct subchannel *sch = to_subchannel(dev);
1284         struct css_driver *drv;
1285
1286         if (!sch->dev.driver)
1287                 return;
1288         drv = to_cssdriver(sch->dev.driver);
1289         if (drv->complete)
1290                 drv->complete(sch);
1291 }
1292
1293 static int css_pm_freeze(struct device *dev)
1294 {
1295         struct subchannel *sch = to_subchannel(dev);
1296         struct css_driver *drv;
1297
1298         if (!sch->dev.driver)
1299                 return 0;
1300         drv = to_cssdriver(sch->dev.driver);
1301         return drv->freeze ? drv->freeze(sch) : 0;
1302 }
1303
1304 static int css_pm_thaw(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->thaw ? drv->thaw(sch) : 0;
1313 }
1314
1315 static int css_pm_restore(struct device *dev)
1316 {
1317         struct subchannel *sch = to_subchannel(dev);
1318         struct css_driver *drv;
1319
1320         css_update_ssd_info(sch);
1321         if (!sch->dev.driver)
1322                 return 0;
1323         drv = to_cssdriver(sch->dev.driver);
1324         return drv->restore ? drv->restore(sch) : 0;
1325 }
1326
1327 static const struct dev_pm_ops css_pm_ops = {
1328         .prepare = css_pm_prepare,
1329         .complete = css_pm_complete,
1330         .freeze = css_pm_freeze,
1331         .thaw = css_pm_thaw,
1332         .restore = css_pm_restore,
1333 };
1334
1335 static struct bus_type css_bus_type = {
1336         .name     = "css",
1337         .match    = css_bus_match,
1338         .probe    = css_probe,
1339         .remove   = css_remove,
1340         .shutdown = css_shutdown,
1341         .uevent   = css_uevent,
1342         .pm = &css_pm_ops,
1343 };
1344
1345 /**
1346  * css_driver_register - register a css driver
1347  * @cdrv: css driver to register
1348  *
1349  * This is mainly a wrapper around driver_register that sets name
1350  * and bus_type in the embedded struct device_driver correctly.
1351  */
1352 int css_driver_register(struct css_driver *cdrv)
1353 {
1354         cdrv->drv.bus = &css_bus_type;
1355         return driver_register(&cdrv->drv);
1356 }
1357 EXPORT_SYMBOL_GPL(css_driver_register);
1358
1359 /**
1360  * css_driver_unregister - unregister a css driver
1361  * @cdrv: css driver to unregister
1362  *
1363  * This is a wrapper around driver_unregister.
1364  */
1365 void css_driver_unregister(struct css_driver *cdrv)
1366 {
1367         driver_unregister(&cdrv->drv);
1368 }
1369 EXPORT_SYMBOL_GPL(css_driver_unregister);