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