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 struct channel_subsystem *channel_subsystems[__MAX_CSSID + 1];
  40 static struct bus_type css_bus_type;
  41
  42 int
  43 for_each_subchannel(int(*fn)(struct subchannel_id, void *), void *data)
  44 {
  45         struct subchannel_id schid;
  46         int ret;
  47
  48         init_subchannel_id(&schid);
  49         do {
  50                 do {
  51                         ret = fn(schid, data);
  52                         if (ret)
  53                                 break;
  54                 } while (schid.sch_no++ < __MAX_SUBCHANNEL);
  55                 schid.sch_no = 0;
  56         } while (schid.ssid++ < max_ssid);
  57         return ret;
  58 }
  59
  60 struct cb_data {
  61         void *data;
  62         struct idset *set;
  63         int (*fn_known_sch)(struct subchannel *, void *);
  64         int (*fn_unknown_sch)(struct subchannel_id, void *);
  65 };
  66
  67 static int call_fn_known_sch(struct device *dev, void *data)
  68 {
  69         struct subchannel *sch = to_subchannel(dev);
  70         struct cb_data *cb = data;
  71         int rc = 0;
  72
  73         if (cb->set)
  74                 idset_sch_del(cb->set, sch->schid);
  75         if (cb->fn_known_sch)
  76                 rc = cb->fn_known_sch(sch, cb->data);
  77         return rc;
  78 }
  79
  80 static int call_fn_unknown_sch(struct subchannel_id schid, void *data)
  81 {
  82         struct cb_data *cb = data;
  83         int rc = 0;
  84
  85         if (idset_sch_contains(cb->set, schid))
  86                 rc = cb->fn_unknown_sch(schid, cb->data);
  87         return rc;
  88 }
  89
  90 static int call_fn_all_sch(struct subchannel_id schid, void *data)
  91 {
  92         struct cb_data *cb = data;
  93         struct subchannel *sch;
  94         int rc = 0;
  95
  96         sch = get_subchannel_by_schid(schid);
  97         if (sch) {
  98                 if (cb->fn_known_sch)
  99                         rc = cb->fn_known_sch(sch, cb->data);
 100                 put_device(&sch->dev);
 101         } else {
 102                 if (cb->fn_unknown_sch)
 103                         rc = cb->fn_unknown_sch(schid, cb->data);
 104         }
 105
 106         return rc;
 107 }
 108
 109 int for_each_subchannel_staged(int (*fn_known)(struct subchannel *, void *),
 110                                int (*fn_unknown)(struct subchannel_id,
 111                                void *), void *data)
 112 {
 113         struct cb_data cb;
 114         int rc;
 115
 116         cb.data = data;
 117         cb.fn_known_sch = fn_known;
 118         cb.fn_unknown_sch = fn_unknown;
 119
 120         if (fn_known && !fn_unknown) {
 121                 /* Skip idset allocation in case of known-only loop. */
 122                 cb.set = NULL;
 123                 return bus_for_each_dev(&css_bus_type, NULL, &cb,
 124                                         call_fn_known_sch);
 125         }
 126
 127         cb.set = idset_sch_new();
 128         if (!cb.set)
 129                 /* fall back to brute force scanning in case of oom */
 130                 return for_each_subchannel(call_fn_all_sch, &cb);
 131
 132         idset_fill(cb.set);
 133
 134         /* Process registered subchannels. */
 135         rc = bus_for_each_dev(&css_bus_type, NULL, &cb, call_fn_known_sch);
 136         if (rc)
 137                 goto out;
 138         /* Process unregistered subchannels. */
 139         if (fn_unknown)
 140                 rc = for_each_subchannel(call_fn_unknown_sch, &cb);
 141 out:
 142         idset_free(cb.set);
 143
 144         return rc;
 145 }
 146
 147 static void css_sch_todo(struct work_struct *work);
 148
 149 static int css_sch_create_locks(struct subchannel *sch)
 150 {
 151         sch->lock = kmalloc(sizeof(*sch->lock), GFP_KERNEL);
 152         if (!sch->lock)
 153                 return -ENOMEM;
 154
 155         spin_lock_init(sch->lock);
 156         mutex_init(&sch->reg_mutex);
 157
 158         return 0;
 159 }
 160
 161 static void css_subchannel_release(struct device *dev)
 162 {
 163         struct subchannel *sch = to_subchannel(dev);
 164
 165         sch->config.intparm = 0;
 166         cio_commit_config(sch);
 167         kfree(sch->lock);
 168         kfree(sch);
 169 }
 170
 171 struct subchannel *css_alloc_subchannel(struct subchannel_id schid)
 172 {
 173         struct subchannel *sch;
 174         int ret;
 175
 176         sch = kzalloc(sizeof(*sch), GFP_KERNEL | GFP_DMA);
 177         if (!sch)
 178                 return ERR_PTR(-ENOMEM);
 179
 180         ret = cio_validate_subchannel(sch, schid);
 181         if (ret < 0)
 182                 goto err;
 183
 184         ret = css_sch_create_locks(sch);
 185         if (ret)
 186                 goto err;
 187
 188         INIT_WORK(&sch->todo_work, css_sch_todo);
 189         sch->dev.release = &css_subchannel_release;
 190         device_initialize(&sch->dev);
 191         return sch;
 192
 193 err:
 194         kfree(sch);
 195         return ERR_PTR(ret);
 196 }
 197
 198 static int css_sch_device_register(struct subchannel *sch)
 199 {
 200         int ret;
 201
 202         mutex_lock(&sch->reg_mutex);
 203         dev_set_name(&sch->dev, "0.%x.%04x", sch->schid.ssid,
 204                      sch->schid.sch_no);
 205         ret = device_add(&sch->dev);
 206         mutex_unlock(&sch->reg_mutex);
 207         return ret;
 208 }
 209
 210 /**
 211  * css_sch_device_unregister - unregister a subchannel
 212  * @sch: subchannel to be unregistered
 213  */
 214 void css_sch_device_unregister(struct subchannel *sch)
 215 {
 216         mutex_lock(&sch->reg_mutex);
 217         if (device_is_registered(&sch->dev))
 218                 device_unregister(&sch->dev);
 219         mutex_unlock(&sch->reg_mutex);
 220 }
 221 EXPORT_SYMBOL_GPL(css_sch_device_unregister);
 222
 223 static void ssd_from_pmcw(struct chsc_ssd_info *ssd, struct pmcw *pmcw)
 224 {
 225         int i;
 226         int mask;
 227
 228         memset(ssd, 0, sizeof(struct chsc_ssd_info));
 229         ssd->path_mask = pmcw->pim;
 230         for (i = 0; i < 8; i++) {
 231                 mask = 0x80 >> i;
 232                 if (pmcw->pim & mask) {
 233                         chp_id_init(&ssd->chpid[i]);
 234                         ssd->chpid[i].id = pmcw->chpid[i];
 235                 }
 236         }
 237 }
 238
 239 static void ssd_register_chpids(struct chsc_ssd_info *ssd)
 240 {
 241         int i;
 242         int mask;
 243
 244         for (i = 0; i < 8; i++) {
 245                 mask = 0x80 >> i;
 246                 if (ssd->path_mask & mask)
 247                         if (!chp_is_registered(ssd->chpid[i]))
 248                                 chp_new(ssd->chpid[i]);
 249         }
 250 }
 251
 252 void css_update_ssd_info(struct subchannel *sch)
 253 {
 254         int ret;
 255
 256         ret = chsc_get_ssd_info(sch->schid, &sch->ssd_info);
 257         if (ret)
 258                 ssd_from_pmcw(&sch->ssd_info, &sch->schib.pmcw);
 259
 260         ssd_register_chpids(&sch->ssd_info);
 261 }
 262
 263 static ssize_t type_show(struct device *dev, struct device_attribute *attr,
 264                          char *buf)
 265 {
 266         struct subchannel *sch = to_subchannel(dev);
 267
 268         return sprintf(buf, "%01x\n", sch->st);
 269 }
 270
 271 static DEVICE_ATTR(type, 0444, type_show, NULL);
 272
 273 static ssize_t modalias_show(struct device *dev, struct device_attribute *attr,
 274                              char *buf)
 275 {
 276         struct subchannel *sch = to_subchannel(dev);
 277
 278         return sprintf(buf, "css:t%01X\n", sch->st);
 279 }
 280
 281 static DEVICE_ATTR(modalias, 0444, modalias_show, NULL);
 282
 283 static struct attribute *subch_attrs[] = {
 284         &dev_attr_type.attr,
 285         &dev_attr_modalias.attr,
 286         NULL,
 287 };
 288
 289 static struct attribute_group subch_attr_group = {
 290         .attrs = subch_attrs,
 291 };
 292
 293 static const struct attribute_group *default_subch_attr_groups[] = {
 294         &subch_attr_group,
 295         NULL,
 296 };
 297
 298 int css_register_subchannel(struct subchannel *sch)
 299 {
 300         int ret;
 301
 302         /* Initialize the subchannel structure */
 303         sch->dev.parent = &channel_subsystems[0]->device;
 304         sch->dev.bus = &css_bus_type;
 305         sch->dev.groups = default_subch_attr_groups;
 306         /*
 307          * We don't want to generate uevents for I/O subchannels that don't
 308          * have a working ccw device behind them since they will be
 309          * unregistered before they can be used anyway, so we delay the add
 310          * uevent until after device recognition was successful.
 311          * Note that we suppress the uevent for all subchannel types;
 312          * the subchannel driver can decide itself when it wants to inform
 313          * userspace of its existence.
 314          */
 315         dev_set_uevent_suppress(&sch->dev, 1);
 316         css_update_ssd_info(sch);
 317         /* make it known to the system */
 318         ret = css_sch_device_register(sch);
 319         if (ret) {
 320                 CIO_MSG_EVENT(0, "Could not register sch 0.%x.%04x: %d\n",
 321                               sch->schid.ssid, sch->schid.sch_no, ret);
 322                 return ret;
 323         }
 324         if (!sch->driver) {
 325                 /*
 326                  * No driver matched. Generate the uevent now so that
 327                  * a fitting driver module may be loaded based on the
 328                  * modalias.
 329                  */
 330                 dev_set_uevent_suppress(&sch->dev, 0);
 331                 kobject_uevent(&sch->dev.kobj, KOBJ_ADD);
 332         }
 333         return ret;
 334 }
 335
 336 static int css_probe_device(struct subchannel_id schid)
 337 {
 338         struct subchannel *sch;
 339         int ret;
 340
 341         sch = css_alloc_subchannel(schid);
 342         if (IS_ERR(sch))
 343                 return PTR_ERR(sch);
 344
 345         ret = css_register_subchannel(sch);
 346         if (ret)
 347                 put_device(&sch->dev);
 348
 349         return ret;
 350 }
 351
 352 static int
 353 check_subchannel(struct device * dev, void * data)
 354 {
 355         struct subchannel *sch;
 356         struct subchannel_id *schid = data;
 357
 358         sch = to_subchannel(dev);
 359         return schid_equal(&sch->schid, schid);
 360 }
 361
 362 struct subchannel *
 363 get_subchannel_by_schid(struct subchannel_id schid)
 364 {
 365         struct device *dev;
 366
 367         dev = bus_find_device(&css_bus_type, NULL,
 368                               &schid, check_subchannel);
 369
 370         return dev ? to_subchannel(dev) : NULL;
 371 }
 372
 373 /**
 374  * css_sch_is_valid() - check if a subchannel is valid
 375  * @schib: subchannel information block for the subchannel
 376  */
 377 int css_sch_is_valid(struct schib *schib)
 378 {
 379         if ((schib->pmcw.st == SUBCHANNEL_TYPE_IO) && !schib->pmcw.dnv)
 380                 return 0;
 381         if ((schib->pmcw.st == SUBCHANNEL_TYPE_MSG) && !schib->pmcw.w)
 382                 return 0;
 383         return 1;
 384 }
 385 EXPORT_SYMBOL_GPL(css_sch_is_valid);
 386
 387 static int css_evaluate_new_subchannel(struct subchannel_id schid, int slow)
 388 {
 389         struct schib schib;
 390
 391         if (!slow) {
 392                 /* Will be done on the slow path. */
 393                 return -EAGAIN;
 394         }
 395         if (stsch(schid, &schib)) {
 396                 /* Subchannel is not provided. */
 397                 return -ENXIO;
 398         }
 399         if (!css_sch_is_valid(&schib)) {
 400                 /* Unusable - ignore. */
 401                 return 0;
 402         }
 403         CIO_MSG_EVENT(4, "event: sch 0.%x.%04x, new\n", schid.ssid,
 404                       schid.sch_no);
 405
 406         return css_probe_device(schid);
 407 }
 408
 409 static int css_evaluate_known_subchannel(struct subchannel *sch, int slow)
 410 {
 411         int ret = 0;
 412
 413         if (sch->driver) {
 414                 if (sch->driver->sch_event)
 415                         ret = sch->driver->sch_event(sch, slow);
 416                 else
 417                         dev_dbg(&sch->dev,
 418                                 "Got subchannel machine check but "
 419                                 "no sch_event handler provided.\n");
 420         }
 421         if (ret != 0 && ret != -EAGAIN) {
 422                 CIO_MSG_EVENT(2, "eval: sch 0.%x.%04x, rc=%d\n",
 423                               sch->schid.ssid, sch->schid.sch_no, ret);
 424         }
 425         return ret;
 426 }
 427
 428 static void css_evaluate_subchannel(struct subchannel_id schid, int slow)
 429 {
 430         struct subchannel *sch;
 431         int ret;
 432
 433         sch = get_subchannel_by_schid(schid);
 434         if (sch) {
 435                 ret = css_evaluate_known_subchannel(sch, slow);
 436                 put_device(&sch->dev);
 437         } else
 438                 ret = css_evaluate_new_subchannel(schid, slow);
 439         if (ret == -EAGAIN)
 440                 css_schedule_eval(schid);
 441 }
 442
 443 /**
 444  * css_sched_sch_todo - schedule a subchannel operation
 445  * @sch: subchannel
 446  * @todo: todo
 447  *
 448  * Schedule the operation identified by @todo to be performed on the slow path
 449  * workqueue. Do nothing if another operation with higher priority is already
 450  * scheduled. Needs to be called with subchannel lock held.
 451  */
 452 void css_sched_sch_todo(struct subchannel *sch, enum sch_todo todo)
 453 {
 454         CIO_MSG_EVENT(4, "sch_todo: sched sch=0.%x.%04x todo=%d\n",
 455                       sch->schid.ssid, sch->schid.sch_no, todo);
 456         if (sch->todo >= todo)
 457                 return;
 458         /* Get workqueue ref. */
 459         if (!get_device(&sch->dev))
 460                 return;
 461         sch->todo = todo;
 462         if (!queue_work(cio_work_q, &sch->todo_work)) {
 463                 /* Already queued, release workqueue ref. */
 464                 put_device(&sch->dev);
 465         }
 466 }
 467 EXPORT_SYMBOL_GPL(css_sched_sch_todo);
 468
 469 static void css_sch_todo(struct work_struct *work)
 470 {
 471         struct subchannel *sch;
 472         enum sch_todo todo;
 473         int ret;
 474
 475         sch = container_of(work, struct subchannel, todo_work);
 476         /* Find out todo. */
 477         spin_lock_irq(sch->lock);
 478         todo = sch->todo;
 479         CIO_MSG_EVENT(4, "sch_todo: sch=0.%x.%04x, todo=%d\n", sch->schid.ssid,
 480                       sch->schid.sch_no, todo);
 481         sch->todo = SCH_TODO_NOTHING;
 482         spin_unlock_irq(sch->lock);
 483         /* Perform todo. */
 484         switch (todo) {
 485         case SCH_TODO_NOTHING:
 486                 break;
 487         case SCH_TODO_EVAL:
 488                 ret = css_evaluate_known_subchannel(sch, 1);
 489                 if (ret == -EAGAIN) {
 490                         spin_lock_irq(sch->lock);
 491                         css_sched_sch_todo(sch, todo);
 492                         spin_unlock_irq(sch->lock);
 493                 }
 494                 break;
 495         case SCH_TODO_UNREG:
 496                 css_sch_device_unregister(sch);
 497                 break;
 498         }
 499         /* Release workqueue ref. */
 500         put_device(&sch->dev);
 501 }
 502
 503 static struct idset *slow_subchannel_set;
 504 static spinlock_t slow_subchannel_lock;
 505 static wait_queue_head_t css_eval_wq;
 506 static atomic_t css_eval_scheduled;
 507
 508 static int __init slow_subchannel_init(void)
 509 {
 510         spin_lock_init(&slow_subchannel_lock);
 511         atomic_set(&css_eval_scheduled, 0);
 512         init_waitqueue_head(&css_eval_wq);
 513         slow_subchannel_set = idset_sch_new();
 514         if (!slow_subchannel_set) {
 515                 CIO_MSG_EVENT(0, "could not allocate slow subchannel set\n");
 516                 return -ENOMEM;
 517         }
 518         return 0;
 519 }
 520
 521 static int slow_eval_known_fn(struct subchannel *sch, void *data)
 522 {
 523         int eval;
 524         int rc;
 525
 526         spin_lock_irq(&slow_subchannel_lock);
 527         eval = idset_sch_contains(slow_subchannel_set, sch->schid);
 528         idset_sch_del(slow_subchannel_set, sch->schid);
 529         spin_unlock_irq(&slow_subchannel_lock);
 530         if (eval) {
 531                 rc = css_evaluate_known_subchannel(sch, 1);
 532                 if (rc == -EAGAIN)
 533                         css_schedule_eval(sch->schid);
 534         }
 535         return 0;
 536 }
 537
 538 static int slow_eval_unknown_fn(struct subchannel_id schid, void *data)
 539 {
 540         int eval;
 541         int rc = 0;
 542
 543         spin_lock_irq(&slow_subchannel_lock);
 544         eval = idset_sch_contains(slow_subchannel_set, schid);
 545         idset_sch_del(slow_subchannel_set, schid);
 546         spin_unlock_irq(&slow_subchannel_lock);
 547         if (eval) {
 548                 rc = css_evaluate_new_subchannel(schid, 1);
 549                 switch (rc) {
 550                 case -EAGAIN:
 551                         css_schedule_eval(schid);
 552                         rc = 0;
 553                         break;
 554                 case -ENXIO:
 555                 case -ENOMEM:
 556                 case -EIO:
 557                         /* These should abort looping */
 558                         spin_lock_irq(&slow_subchannel_lock);
 559                         idset_sch_del_subseq(slow_subchannel_set, schid);
 560                         spin_unlock_irq(&slow_subchannel_lock);
 561                         break;
 562                 default:
 563                         rc = 0;
 564                 }
 565                 /* Allow scheduling here since the containing loop might
 566                  * take a while.  */
 567                 cond_resched();
 568         }
 569         return rc;
 570 }
 571
 572 static void css_slow_path_func(struct work_struct *unused)
 573 {
 574         unsigned long flags;
 575
 576         CIO_TRACE_EVENT(4, "slowpath");
 577         for_each_subchannel_staged(slow_eval_known_fn, slow_eval_unknown_fn,
 578                                    NULL);
 579         spin_lock_irqsave(&slow_subchannel_lock, flags);
 580         if (idset_is_empty(slow_subchannel_set)) {
 581                 atomic_set(&css_eval_scheduled, 0);
 582                 wake_up(&css_eval_wq);
 583         }
 584         spin_unlock_irqrestore(&slow_subchannel_lock, flags);
 585 }
 586
 587 static DECLARE_DELAYED_WORK(slow_path_work, css_slow_path_func);
 588 struct workqueue_struct *cio_work_q;
 589
 590 void css_schedule_eval(struct subchannel_id schid)
 591 {
 592         unsigned long flags;
 593
 594         spin_lock_irqsave(&slow_subchannel_lock, flags);
 595         idset_sch_add(slow_subchannel_set, schid);
 596         atomic_set(&css_eval_scheduled, 1);
 597         queue_delayed_work(cio_work_q, &slow_path_work, 0);
 598         spin_unlock_irqrestore(&slow_subchannel_lock, flags);
 599 }
 600
 601 void css_schedule_eval_all(void)
 602 {
 603         unsigned long flags;
 604
 605         spin_lock_irqsave(&slow_subchannel_lock, flags);
 606         idset_fill(slow_subchannel_set);
 607         atomic_set(&css_eval_scheduled, 1);
 608         queue_delayed_work(cio_work_q, &slow_path_work, 0);
 609         spin_unlock_irqrestore(&slow_subchannel_lock, flags);
 610 }
 611
 612 static int __unset_registered(struct device *dev, void *data)
 613 {
 614         struct idset *set = data;
 615         struct subchannel *sch = to_subchannel(dev);
 616
 617         idset_sch_del(set, sch->schid);
 618         return 0;
 619 }
 620
 621 void css_schedule_eval_all_unreg(unsigned long delay)
 622 {
 623         unsigned long flags;
 624         struct idset *unreg_set;
 625
 626         /* Find unregistered subchannels. */
 627         unreg_set = idset_sch_new();
 628         if (!unreg_set) {
 629                 /* Fallback. */
 630                 css_schedule_eval_all();
 631                 return;
 632         }
 633         idset_fill(unreg_set);
 634         bus_for_each_dev(&css_bus_type, NULL, unreg_set, __unset_registered);
 635         /* Apply to slow_subchannel_set. */
 636         spin_lock_irqsave(&slow_subchannel_lock, flags);
 637         idset_add_set(slow_subchannel_set, unreg_set);
 638         atomic_set(&css_eval_scheduled, 1);
 639         queue_delayed_work(cio_work_q, &slow_path_work, delay);
 640         spin_unlock_irqrestore(&slow_subchannel_lock, flags);
 641         idset_free(unreg_set);
 642 }
 643
 644 void css_wait_for_slow_path(void)
 645 {
 646         flush_workqueue(cio_work_q);
 647 }
 648
 649 /* Schedule reprobing of all unregistered subchannels. */
 650 void css_schedule_reprobe(void)
 651 {
 652         /* Schedule with a delay to allow merging of subsequent calls. */
 653         css_schedule_eval_all_unreg(1 * HZ);
 654 }
 655 EXPORT_SYMBOL_GPL(css_schedule_reprobe);
 656
 657 /*
 658  * Called from the machine check handler for subchannel report words.
 659  */
 660 static void css_process_crw(struct crw *crw0, struct crw *crw1, int overflow)
 661 {
 662         struct subchannel_id mchk_schid;
 663         struct subchannel *sch;
 664
 665         if (overflow) {
 666                 css_schedule_eval_all();
 667                 return;
 668         }
 669         CIO_CRW_EVENT(2, "CRW0 reports slct=%d, oflw=%d, "
 670                       "chn=%d, rsc=%X, anc=%d, erc=%X, rsid=%X\n",
 671                       crw0->slct, crw0->oflw, crw0->chn, crw0->rsc, crw0->anc,
 672                       crw0->erc, crw0->rsid);
 673         if (crw1)
 674                 CIO_CRW_EVENT(2, "CRW1 reports slct=%d, oflw=%d, "
 675                               "chn=%d, rsc=%X, anc=%d, erc=%X, rsid=%X\n",
 676                               crw1->slct, crw1->oflw, crw1->chn, crw1->rsc,
 677                               crw1->anc, crw1->erc, crw1->rsid);
 678         init_subchannel_id(&mchk_schid);
 679         mchk_schid.sch_no = crw0->rsid;
 680         if (crw1)
 681                 mchk_schid.ssid = (crw1->rsid >> 4) & 3;
 682
 683         if (crw0->erc == CRW_ERC_PMOD) {
 684                 sch = get_subchannel_by_schid(mchk_schid);
 685                 if (sch) {
 686                         css_update_ssd_info(sch);
 687                         put_device(&sch->dev);
 688                 }
 689         }
 690         /*
 691          * Since we are always presented with IPI in the CRW, we have to
 692          * use stsch() to find out if the subchannel in question has come
 693          * or gone.
 694          */
 695         css_evaluate_subchannel(mchk_schid, 0);
 696 }
 697
 698 static void __init
 699 css_generate_pgid(struct channel_subsystem *css, u32 tod_high)
 700 {
 701         struct cpuid cpu_id;
 702
 703         if (css_general_characteristics.mcss) {
 704                 css->global_pgid.pgid_high.ext_cssid.version = 0x80;
 705                 css->global_pgid.pgid_high.ext_cssid.cssid = css->cssid;
 706         } else {
 707                 css->global_pgid.pgid_high.cpu_addr = stap();
 708         }
 709         get_cpu_id(&cpu_id);
 710         css->global_pgid.cpu_id = cpu_id.ident;
 711         css->global_pgid.cpu_model = cpu_id.machine;
 712         css->global_pgid.tod_high = tod_high;
 713 }
 714
 715 static void
 716 channel_subsystem_release(struct device *dev)
 717 {
 718         struct channel_subsystem *css;
 719
 720         css = to_css(dev);
 721         mutex_destroy(&css->mutex);
 722         if (css->pseudo_subchannel) {
 723                 /* Implies that it has been generated but never registered. */
 724                 css_subchannel_release(&css->pseudo_subchannel->dev);
 725                 css->pseudo_subchannel = NULL;
 726         }
 727         kfree(css);
 728 }
 729
 730 static ssize_t
 731 css_cm_enable_show(struct device *dev, struct device_attribute *attr,
 732                    char *buf)
 733 {
 734         struct channel_subsystem *css = to_css(dev);
 735         int ret;
 736
 737         if (!css)
 738                 return 0;
 739         mutex_lock(&css->mutex);
 740         ret = sprintf(buf, "%x\n", css->cm_enabled);
 741         mutex_unlock(&css->mutex);
 742         return ret;
 743 }
 744
 745 static ssize_t
 746 css_cm_enable_store(struct device *dev, struct device_attribute *attr,
 747                     const char *buf, size_t count)
 748 {
 749         struct channel_subsystem *css = to_css(dev);
 750         int ret;
 751         unsigned long val;
 752
 753         ret = kstrtoul(buf, 16, &val);
 754         if (ret)
 755                 return ret;
 756         mutex_lock(&css->mutex);
 757         switch (val) {
 758         case 0:
 759                 ret = css->cm_enabled ? chsc_secm(css, 0) : 0;
 760                 break;
 761         case 1:
 762                 ret = css->cm_enabled ? 0 : chsc_secm(css, 1);
 763                 break;
 764         default:
 765                 ret = -EINVAL;
 766         }
 767         mutex_unlock(&css->mutex);
 768         return ret < 0 ? ret : count;
 769 }
 770
 771 static DEVICE_ATTR(cm_enable, 0644, css_cm_enable_show, css_cm_enable_store);
 772
 773 static int __init setup_css(int nr)
 774 {
 775         u32 tod_high;
 776         int ret;
 777         struct channel_subsystem *css;
 778
 779         css = channel_subsystems[nr];
 780         memset(css, 0, sizeof(struct channel_subsystem));
 781         css->pseudo_subchannel =
 782                 kzalloc(sizeof(*css->pseudo_subchannel), GFP_KERNEL);
 783         if (!css->pseudo_subchannel)
 784                 return -ENOMEM;
 785         css->pseudo_subchannel->dev.parent = &css->device;
 786         css->pseudo_subchannel->dev.release = css_subchannel_release;
 787         dev_set_name(&css->pseudo_subchannel->dev, "defunct");
 788         mutex_init(&css->pseudo_subchannel->reg_mutex);
 789         ret = css_sch_create_locks(css->pseudo_subchannel);
 790         if (ret) {
 791                 kfree(css->pseudo_subchannel);
 792                 return ret;
 793         }
 794         mutex_init(&css->mutex);
 795         css->valid = 1;
 796         css->cssid = nr;
 797         dev_set_name(&css->device, "css%x", nr);
 798         css->device.release = channel_subsystem_release;
 799         tod_high = (u32) (get_tod_clock() >> 32);
 800         css_generate_pgid(css, tod_high);
 801         return 0;
 802 }
 803
 804 static int css_reboot_event(struct notifier_block *this,
 805                             unsigned long event,
 806                             void *ptr)
 807 {
 808         int ret, i;
 809
 810         ret = NOTIFY_DONE;
 811         for (i = 0; i <= __MAX_CSSID; i++) {
 812                 struct channel_subsystem *css;
 813
 814                 css = channel_subsystems[i];
 815                 mutex_lock(&css->mutex);
 816                 if (css->cm_enabled)
 817                         if (chsc_secm(css, 0))
 818                                 ret = NOTIFY_BAD;
 819                 mutex_unlock(&css->mutex);
 820         }
 821
 822         return ret;
 823 }
 824
 825 static struct notifier_block css_reboot_notifier = {
 826         .notifier_call = css_reboot_event,
 827 };
 828
 829 /*
 830  * Since the css devices are neither on a bus nor have a class
 831  * nor have a special device type, we cannot stop/restart channel
 832  * path measurements via the normal suspend/resume callbacks, but have
 833  * to use notifiers.
 834  */
 835 static int css_power_event(struct notifier_block *this, unsigned long event,
 836                            void *ptr)
 837 {
 838         int ret, i;
 839
 840         switch (event) {
 841         case PM_HIBERNATION_PREPARE:
 842         case PM_SUSPEND_PREPARE:
 843                 ret = NOTIFY_DONE;
 844                 for (i = 0; i <= __MAX_CSSID; i++) {
 845                         struct channel_subsystem *css;
 846
 847                         css = channel_subsystems[i];
 848                         mutex_lock(&css->mutex);
 849                         if (!css->cm_enabled) {
 850                                 mutex_unlock(&css->mutex);
 851                                 continue;
 852                         }
 853                         ret = __chsc_do_secm(css, 0);
 854                         ret = notifier_from_errno(ret);
 855                         mutex_unlock(&css->mutex);
 856                 }
 857                 break;
 858         case PM_POST_HIBERNATION:
 859         case PM_POST_SUSPEND:
 860                 ret = NOTIFY_DONE;
 861                 for (i = 0; i <= __MAX_CSSID; i++) {
 862                         struct channel_subsystem *css;
 863
 864                         css = channel_subsystems[i];
 865                         mutex_lock(&css->mutex);
 866                         if (!css->cm_enabled) {
 867                                 mutex_unlock(&css->mutex);
 868                                 continue;
 869                         }
 870                         ret = __chsc_do_secm(css, 1);
 871                         ret = notifier_from_errno(ret);
 872                         mutex_unlock(&css->mutex);
 873                 }
 874                 /* search for subchannels, which appeared during hibernation */
 875                 css_schedule_reprobe();
 876                 break;
 877         default:
 878                 ret = NOTIFY_DONE;
 879         }
 880         return ret;
 881
 882 }
 883 static struct notifier_block css_power_notifier = {
 884         .notifier_call = css_power_event,
 885 };
 886
 887 /*
 888  * Now that the driver core is running, we can setup our channel subsystem.
 889  * The struct subchannel's are created during probing.
 890  */
 891 static int __init css_bus_init(void)
 892 {
 893         int ret, i;
 894
 895         ret = chsc_init();
 896         if (ret)
 897                 return ret;
 898
 899         chsc_determine_css_characteristics();
 900         /* Try to enable MSS. */
 901         ret = chsc_enable_facility(CHSC_SDA_OC_MSS);
 902         if (ret)
 903                 max_ssid = 0;
 904         else /* Success. */
 905                 max_ssid = __MAX_SSID;
 906
 907         ret = slow_subchannel_init();
 908         if (ret)
 909                 goto out;
 910
 911         ret = crw_register_handler(CRW_RSC_SCH, css_process_crw);
 912         if (ret)
 913                 goto out;
 914
 915         if ((ret = bus_register(&css_bus_type)))
 916                 goto out;
 917
 918         /* Setup css structure. */
 919         for (i = 0; i <= __MAX_CSSID; i++) {
 920                 struct channel_subsystem *css;
 921
 922                 css = kmalloc(sizeof(struct channel_subsystem), GFP_KERNEL);
 923                 if (!css) {
 924                         ret = -ENOMEM;
 925                         goto out_unregister;
 926                 }
 927                 channel_subsystems[i] = css;
 928                 ret = setup_css(i);
 929                 if (ret) {
 930                         kfree(channel_subsystems[i]);
 931                         goto out_unregister;
 932                 }
 933                 ret = device_register(&css->device);
 934                 if (ret) {
 935                         put_device(&css->device);
 936                         goto out_unregister;
 937                 }
 938                 if (css_chsc_characteristics.secm) {
 939                         ret = device_create_file(&css->device,
 940                                                  &dev_attr_cm_enable);
 941                         if (ret)
 942                                 goto out_device;
 943                 }
 944                 ret = device_register(&css->pseudo_subchannel->dev);
 945                 if (ret) {
 946                         put_device(&css->pseudo_subchannel->dev);
 947                         goto out_file;
 948                 }
 949         }
 950         ret = register_reboot_notifier(&css_reboot_notifier);
 951         if (ret)
 952                 goto out_unregister;
 953         ret = register_pm_notifier(&css_power_notifier);
 954         if (ret) {
 955                 unregister_reboot_notifier(&css_reboot_notifier);
 956                 goto out_unregister;
 957         }
 958         css_init_done = 1;
 959
 960         /* Enable default isc for I/O subchannels. */
 961         isc_register(IO_SCH_ISC);
 962
 963         return 0;
 964 out_file:
 965         if (css_chsc_characteristics.secm)
 966                 device_remove_file(&channel_subsystems[i]->device,
 967                                    &dev_attr_cm_enable);
 968 out_device:
 969         device_unregister(&channel_subsystems[i]->device);
 970 out_unregister:
 971         while (i > 0) {
 972                 struct channel_subsystem *css;
 973
 974                 i--;
 975                 css = channel_subsystems[i];
 976                 device_unregister(&css->pseudo_subchannel->dev);
 977                 css->pseudo_subchannel = NULL;
 978                 if (css_chsc_characteristics.secm)
 979                         device_remove_file(&css->device,
 980                                            &dev_attr_cm_enable);
 981                 device_unregister(&css->device);
 982         }
 983         bus_unregister(&css_bus_type);
 984 out:
 985         crw_unregister_handler(CRW_RSC_SCH);
 986         idset_free(slow_subchannel_set);
 987         chsc_init_cleanup();
 988         pr_alert("The CSS device driver initialization failed with "
 989                  "errno=%d\n", ret);
 990         return ret;
 991 }
 992
 993 static void __init css_bus_cleanup(void)
 994 {
 995         struct channel_subsystem *css;
 996         int i;
 997
 998         for (i = 0; i <= __MAX_CSSID; i++) {
 999                 css = channel_subsystems[i];
1000                 device_unregister(&css->pseudo_subchannel->dev);
1001                 css->pseudo_subchannel = NULL;
1002                 if (css_chsc_characteristics.secm)
1003                         device_remove_file(&css->device, &dev_attr_cm_enable);
1004                 device_unregister(&css->device);
1005         }
1006         bus_unregister(&css_bus_type);
1007         crw_unregister_handler(CRW_RSC_SCH);
1008         idset_free(slow_subchannel_set);
1009         chsc_init_cleanup();
1010         isc_unregister(IO_SCH_ISC);
1011 }
1012
1013 static int __init channel_subsystem_init(void)
1014 {
1015         int ret;
1016
1017         ret = css_bus_init();
1018         if (ret)
1019                 return ret;
1020         cio_work_q = create_singlethread_workqueue("cio");
1021         if (!cio_work_q) {
1022                 ret = -ENOMEM;
1023                 goto out_bus;
1024         }
1025         ret = io_subchannel_init();
1026         if (ret)
1027                 goto out_wq;
1028
1029         return ret;
1030 out_wq:
1031         destroy_workqueue(cio_work_q);
1032 out_bus:
1033         css_bus_cleanup();
1034         return ret;
1035 }
1036 subsys_initcall(channel_subsystem_init);
1037
1038 static int css_settle(struct device_driver *drv, void *unused)
1039 {
1040         struct css_driver *cssdrv = to_cssdriver(drv);
1041
1042         if (cssdrv->settle)
1043                 return cssdrv->settle();
1044         return 0;
1045 }
1046
1047 int css_complete_work(void)
1048 {
1049         int ret;
1050
1051         /* Wait for the evaluation of subchannels to finish. */
1052         ret = wait_event_interruptible(css_eval_wq,
1053                                        atomic_read(&css_eval_scheduled) == 0);
1054         if (ret)
1055                 return -EINTR;
1056         flush_workqueue(cio_work_q);
1057         /* Wait for the subchannel type specific initialization to finish */
1058         return bus_for_each_drv(&css_bus_type, NULL, NULL, css_settle);
1059 }
1060
1061
1062 /*
1063  * Wait for the initialization of devices to finish, to make sure we are
1064  * done with our setup if the search for the root device starts.
1065  */
1066 static int __init channel_subsystem_init_sync(void)
1067 {
1068         /* Register subchannels which are already in use. */
1069         cio_register_early_subchannels();
1070         /* Start initial subchannel evaluation. */
1071         css_schedule_eval_all();
1072         css_complete_work();
1073         return 0;
1074 }
1075 subsys_initcall_sync(channel_subsystem_init_sync);
1076
1077 void channel_subsystem_reinit(void)
1078 {
1079         struct channel_path *chp;
1080         struct chp_id chpid;
1081
1082         chsc_enable_facility(CHSC_SDA_OC_MSS);
1083         chp_id_for_each(&chpid) {
1084                 chp = chpid_to_chp(chpid);
1085                 if (chp)
1086                         chp_update_desc(chp);
1087         }
1088         cmf_reactivate();
1089 }
1090
1091 #ifdef CONFIG_PROC_FS
1092 static ssize_t cio_settle_write(struct file *file, const char __user *buf,
1093                                 size_t count, loff_t *ppos)
1094 {
1095         int ret;
1096
1097         /* Handle pending CRW's. */
1098         crw_wait_for_channel_report();
1099         ret = css_complete_work();
1100
1101         return ret ? ret : count;
1102 }
1103
1104 static const struct file_operations cio_settle_proc_fops = {
1105         .open = nonseekable_open,
1106         .write = cio_settle_write,
1107         .llseek = no_llseek,
1108 };
1109
1110 static int __init cio_settle_init(void)
1111 {
1112         struct proc_dir_entry *entry;
1113
1114         entry = proc_create("cio_settle", S_IWUSR, NULL,
1115                             &cio_settle_proc_fops);
1116         if (!entry)
1117                 return -ENOMEM;
1118         return 0;
1119 }
1120 device_initcall(cio_settle_init);
1121 #endif /*CONFIG_PROC_FS*/
1122
1123 int sch_is_pseudo_sch(struct subchannel *sch)
1124 {
1125         return sch == to_css(sch->dev.parent)->pseudo_subchannel;
1126 }
1127
1128 static int css_bus_match(struct device *dev, struct device_driver *drv)
1129 {
1130         struct subchannel *sch = to_subchannel(dev);
1131         struct css_driver *driver = to_cssdriver(drv);
1132         struct css_device_id *id;
1133
1134         for (id = driver->subchannel_type; id->match_flags; id++) {
1135                 if (sch->st == id->type)
1136                         return 1;
1137         }
1138
1139         return 0;
1140 }
1141
1142 static int css_probe(struct device *dev)
1143 {
1144         struct subchannel *sch;
1145         int ret;
1146
1147         sch = to_subchannel(dev);
1148         sch->driver = to_cssdriver(dev->driver);
1149         ret = sch->driver->probe ? sch->driver->probe(sch) : 0;
1150         if (ret)
1151                 sch->driver = NULL;
1152         return ret;
1153 }
1154
1155 static int css_remove(struct device *dev)
1156 {
1157         struct subchannel *sch;
1158         int ret;
1159
1160         sch = to_subchannel(dev);
1161         ret = sch->driver->remove ? sch->driver->remove(sch) : 0;
1162         sch->driver = NULL;
1163         return ret;
1164 }
1165
1166 static void css_shutdown(struct device *dev)
1167 {
1168         struct subchannel *sch;
1169
1170         sch = to_subchannel(dev);
1171         if (sch->driver && sch->driver->shutdown)
1172                 sch->driver->shutdown(sch);
1173 }
1174
1175 static int css_uevent(struct device *dev, struct kobj_uevent_env *env)
1176 {
1177         struct subchannel *sch = to_subchannel(dev);
1178         int ret;
1179
1180         ret = add_uevent_var(env, "ST=%01X", sch->st);
1181         if (ret)
1182                 return ret;
1183         ret = add_uevent_var(env, "MODALIAS=css:t%01X", sch->st);
1184         return ret;
1185 }
1186
1187 static int css_pm_prepare(struct device *dev)
1188 {
1189         struct subchannel *sch = to_subchannel(dev);
1190         struct css_driver *drv;
1191
1192         if (mutex_is_locked(&sch->reg_mutex))
1193                 return -EAGAIN;
1194         if (!sch->dev.driver)
1195                 return 0;
1196         drv = to_cssdriver(sch->dev.driver);
1197         /* Notify drivers that they may not register children. */
1198         return drv->prepare ? drv->prepare(sch) : 0;
1199 }
1200
1201 static void css_pm_complete(struct device *dev)
1202 {
1203         struct subchannel *sch = to_subchannel(dev);
1204         struct css_driver *drv;
1205
1206         if (!sch->dev.driver)
1207                 return;
1208         drv = to_cssdriver(sch->dev.driver);
1209         if (drv->complete)
1210                 drv->complete(sch);
1211 }
1212
1213 static int css_pm_freeze(struct device *dev)
1214 {
1215         struct subchannel *sch = to_subchannel(dev);
1216         struct css_driver *drv;
1217
1218         if (!sch->dev.driver)
1219                 return 0;
1220         drv = to_cssdriver(sch->dev.driver);
1221         return drv->freeze ? drv->freeze(sch) : 0;
1222 }
1223
1224 static int css_pm_thaw(struct device *dev)
1225 {
1226         struct subchannel *sch = to_subchannel(dev);
1227         struct css_driver *drv;
1228
1229         if (!sch->dev.driver)
1230                 return 0;
1231         drv = to_cssdriver(sch->dev.driver);
1232         return drv->thaw ? drv->thaw(sch) : 0;
1233 }
1234
1235 static int css_pm_restore(struct device *dev)
1236 {
1237         struct subchannel *sch = to_subchannel(dev);
1238         struct css_driver *drv;
1239
1240         css_update_ssd_info(sch);
1241         if (!sch->dev.driver)
1242                 return 0;
1243         drv = to_cssdriver(sch->dev.driver);
1244         return drv->restore ? drv->restore(sch) : 0;
1245 }
1246
1247 static const struct dev_pm_ops css_pm_ops = {
1248         .prepare = css_pm_prepare,
1249         .complete = css_pm_complete,
1250         .freeze = css_pm_freeze,
1251         .thaw = css_pm_thaw,
1252         .restore = css_pm_restore,
1253 };
1254
1255 static struct bus_type css_bus_type = {
1256         .name     = "css",
1257         .match    = css_bus_match,
1258         .probe    = css_probe,
1259         .remove   = css_remove,
1260         .shutdown = css_shutdown,
1261         .uevent   = css_uevent,
1262         .pm = &css_pm_ops,
1263 };
1264
1265 /**
1266  * css_driver_register - register a css driver
1267  * @cdrv: css driver to register
1268  *
1269  * This is mainly a wrapper around driver_register that sets name
1270  * and bus_type in the embedded struct device_driver correctly.
1271  */
1272 int css_driver_register(struct css_driver *cdrv)
1273 {
1274         cdrv->drv.bus = &css_bus_type;
1275         return driver_register(&cdrv->drv);
1276 }
1277 EXPORT_SYMBOL_GPL(css_driver_register);
1278
1279 /**
1280  * css_driver_unregister - unregister a css driver
1281  * @cdrv: css driver to unregister
1282  *
1283  * This is a wrapper around driver_unregister.
1284  */
1285 void css_driver_unregister(struct css_driver *cdrv)
1286 {
1287         driver_unregister(&cdrv->drv);
1288 }
1289 EXPORT_SYMBOL_GPL(css_driver_unregister);