kernel/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
  10 #define KMSG_COMPONENT "cio"
  11 #define pr_fmt(fmt) KMSG_COMPONENT ": " fmt
  12
  13 #include <linux/module.h>
  14 #include <linux/init.h>
  15 #include <linux/device.h>
  16 #include <linux/slab.h>
  17 #include <linux/errno.h>
  18 #include <linux/list.h>
  19 #include <linux/reboot.h>
  20 #include <linux/suspend.h>
  21 #include <linux/proc_fs.h>
  22 #include <asm/isc.h>
  23 #include <asm/crw.h>
  24
  25 #include "css.h"
  26 #include "cio.h"
  27 #include "cio_debug.h"
  28 #include "ioasm.h"
  29 #include "chsc.h"
  30 #include "device.h"
  31 #include "idset.h"
  32 #include "chp.h"
  33
  34 int css_init_done = 0;
  35 int max_ssid;
  36
  37 struct channel_subsystem *channel_subsystems[__MAX_CSSID + 1];
  38 static struct bus_type css_bus_type;
  39
  40 int
  41 for_each_subchannel(int(*fn)(struct subchannel_id, void *), void *data)
  42 {
  43         struct subchannel_id schid;
  44         int ret;
  45
  46         init_subchannel_id(&schid);
  47         ret = -ENODEV;
  48         do {
  49                 do {
  50                         ret = fn(schid, data);
  51                         if (ret)
  52                                 break;
  53                 } while (schid.sch_no++ < __MAX_SUBCHANNEL);
  54                 schid.sch_no = 0;
  55         } while (schid.ssid++ < max_ssid);
  56         return ret;
  57 }
  58
  59 struct cb_data {
  60         void *data;
  61         struct idset *set;
  62         int (*fn_known_sch)(struct subchannel *, void *);
  63         int (*fn_unknown_sch)(struct subchannel_id, void *);
  64 };
  65
  66 static int call_fn_known_sch(struct device *dev, void *data)
  67 {
  68         struct subchannel *sch = to_subchannel(dev);
  69         struct cb_data *cb = data;
  70         int rc = 0;
  71
  72         if (cb->set)
  73                 idset_sch_del(cb->set, sch->schid);
  74         if (cb->fn_known_sch)
  75                 rc = cb->fn_known_sch(sch, cb->data);
  76         return rc;
  77 }
  78
  79 static int call_fn_unknown_sch(struct subchannel_id schid, void *data)
  80 {
  81         struct cb_data *cb = data;
  82         int rc = 0;
  83
  84         if (idset_sch_contains(cb->set, schid))
  85                 rc = cb->fn_unknown_sch(schid, cb->data);
  86         return rc;
  87 }
  88
  89 static int call_fn_all_sch(struct subchannel_id schid, void *data)
  90 {
  91         struct cb_data *cb = data;
  92         struct subchannel *sch;
  93         int rc = 0;
  94
  95         sch = get_subchannel_by_schid(schid);
  96         if (sch) {
  97                 if (cb->fn_known_sch)
  98                         rc = cb->fn_known_sch(sch, cb->data);
  99                 put_device(&sch->dev);
 100         } else {
 101                 if (cb->fn_unknown_sch)
 102                         rc = cb->fn_unknown_sch(schid, cb->data);
 103         }
 104
 105         return rc;
 106 }
 107
 108 int for_each_subchannel_staged(int (*fn_known)(struct subchannel *, void *),
 109                                int (*fn_unknown)(struct subchannel_id,
 110                                void *), void *data)
 111 {
 112         struct cb_data cb;
 113         int rc;
 114
 115         cb.data = data;
 116         cb.fn_known_sch = fn_known;
 117         cb.fn_unknown_sch = fn_unknown;
 118
 119         if (fn_known && !fn_unknown) {
 120                 /* Skip idset allocation in case of known-only loop. */
 121                 cb.set = NULL;
 122                 return bus_for_each_dev(&css_bus_type, NULL, &cb,
 123                                         call_fn_known_sch);
 124         }
 125
 126         cb.set = idset_sch_new();
 127         if (!cb.set)
 128                 /* fall back to brute force scanning in case of oom */
 129                 return for_each_subchannel(call_fn_all_sch, &cb);
 130
 131         idset_fill(cb.set);
 132
 133         /* Process registered subchannels. */
 134         rc = bus_for_each_dev(&css_bus_type, NULL, &cb, call_fn_known_sch);
 135         if (rc)
 136                 goto out;
 137         /* Process unregistered subchannels. */
 138         if (fn_unknown)
 139                 rc = for_each_subchannel(call_fn_unknown_sch, &cb);
 140 out:
 141         idset_free(cb.set);
 142
 143         return rc;
 144 }
 145
 146 static void css_sch_todo(struct work_struct *work);
 147
 148 static int css_sch_create_locks(struct subchannel *sch)
 149 {
 150         sch->lock = kmalloc(sizeof(*sch->lock), GFP_KERNEL);
 151         if (!sch->lock)
 152                 return -ENOMEM;
 153
 154         spin_lock_init(sch->lock);
 155         mutex_init(&sch->reg_mutex);
 156
 157         return 0;
 158 }
 159
 160 static void css_subchannel_release(struct device *dev)
 161 {
 162         struct subchannel *sch = to_subchannel(dev);
 163
 164         sch->config.intparm = 0;
 165         cio_commit_config(sch);
 166         kfree(sch->lock);
 167         kfree(sch);
 168 }
 169
 170 struct subchannel *css_alloc_subchannel(struct subchannel_id schid)
 171 {
 172         struct subchannel *sch;
 173         int ret;
 174
 175         sch = kzalloc(sizeof(*sch), GFP_KERNEL | GFP_DMA);
 176         if (!sch)
 177                 return ERR_PTR(-ENOMEM);
 178
 179         ret = cio_validate_subchannel(sch, schid);
 180         if (ret < 0)
 181                 goto err;
 182
 183         ret = css_sch_create_locks(sch);
 184         if (ret)
 185                 goto err;
 186
 187         INIT_WORK(&sch->todo_work, css_sch_todo);
 188         sch->dev.release = &css_subchannel_release;
 189         device_initialize(&sch->dev);
 190         return sch;
 191
 192 err:
 193         kfree(sch);
 194         return ERR_PTR(ret);
 195 }
 196
 197 static int css_sch_device_register(struct subchannel *sch)
 198 {
 199         int ret;
 200
 201         mutex_lock(&sch->reg_mutex);
 202         dev_set_name(&sch->dev, "0.%x.%04x", sch->schid.ssid,
 203                      sch->schid.sch_no);
 204         ret = device_add(&sch->dev);
 205         mutex_unlock(&sch->reg_mutex);
 206         return ret;
 207 }
 208
 209 /**
 210  * css_sch_device_unregister - unregister a subchannel
 211  * @sch: subchannel to be unregistered
 212  */
 213 void css_sch_device_unregister(struct subchannel *sch)
 214 {
 215         mutex_lock(&sch->reg_mutex);
 216         if (device_is_registered(&sch->dev))
 217                 device_unregister(&sch->dev);
 218         mutex_unlock(&sch->reg_mutex);
 219 }
 220 EXPORT_SYMBOL_GPL(css_sch_device_unregister);
 221
 222 static void ssd_from_pmcw(struct chsc_ssd_info *ssd, struct pmcw *pmcw)
 223 {
 224         int i;
 225         int mask;
 226
 227         memset(ssd, 0, sizeof(struct chsc_ssd_info));
 228         ssd->path_mask = pmcw->pim;
 229         for (i = 0; i < 8; i++) {
 230                 mask = 0x80 >> i;
 231                 if (pmcw->pim & mask) {
 232                         chp_id_init(&ssd->chpid[i]);
 233                         ssd->chpid[i].id = pmcw->chpid[i];
 234                 }
 235         }
 236 }
 237
 238 static void ssd_register_chpids(struct chsc_ssd_info *ssd)
 239 {
 240         int i;
 241         int mask;
 242
 243         for (i = 0; i < 8; i++) {
 244                 mask = 0x80 >> i;
 245                 if (ssd->path_mask & mask)
 246                         if (!chp_is_registered(ssd->chpid[i]))
 247                                 chp_new(ssd->chpid[i]);
 248         }
 249 }
 250
 251 void css_update_ssd_info(struct subchannel *sch)
 252 {
 253         int ret;
 254
 255         ret = chsc_get_ssd_info(sch->schid, &sch->ssd_info);
 256         if (ret)
 257                 ssd_from_pmcw(&sch->ssd_info, &sch->schib.pmcw);
 258
 259         ssd_register_chpids(&sch->ssd_info);
 260 }
 261
 262 static ssize_t type_show(struct device *dev, struct device_attribute *attr,
 263                          char *buf)
 264 {
 265         struct subchannel *sch = to_subchannel(dev);
 266
 267         return sprintf(buf, "%01x\n", sch->st);
 268 }
 269
 270 static DEVICE_ATTR(type, 0444, type_show, NULL);
 271
 272 static ssize_t modalias_show(struct device *dev, struct device_attribute *attr,
 273                              char *buf)
 274 {
 275         struct subchannel *sch = to_subchannel(dev);
 276
 277         return sprintf(buf, "css:t%01X\n", sch->st);
 278 }
 279
 280 static DEVICE_ATTR(modalias, 0444, modalias_show, NULL);
 281
 282 static struct attribute *subch_attrs[] = {
 283         &dev_attr_type.attr,
 284         &dev_attr_modalias.attr,
 285         NULL,
 286 };
 287
 288 static struct attribute_group subch_attr_group = {
 289         .attrs = subch_attrs,
 290 };
 291
 292 static const struct attribute_group *default_subch_attr_groups[] = {
 293         &subch_attr_group,
 294         NULL,
 295 };
 296
 297 int css_register_subchannel(struct subchannel *sch)
 298 {
 299         int ret;
 300
 301         /* Initialize the subchannel structure */
 302         sch->dev.parent = &channel_subsystems[0]->device;
 303         sch->dev.bus = &css_bus_type;
 304         sch->dev.groups = default_subch_attr_groups;
 305         /*
 306          * We don't want to generate uevents for I/O subchannels that don't
 307          * have a working ccw device behind them since they will be
 308          * unregistered before they can be used anyway, so we delay the add
 309          * uevent until after device recognition was successful.
 310          * Note that we suppress the uevent for all subchannel types;
 311          * the subchannel driver can decide itself when it wants to inform
 312          * userspace of its existence.
 313          */
 314         dev_set_uevent_suppress(&sch->dev, 1);
 315         css_update_ssd_info(sch);
 316         /* make it known to the system */
 317         ret = css_sch_device_register(sch);
 318         if (ret) {
 319                 CIO_MSG_EVENT(0, "Could not register sch 0.%x.%04x: %d\n",
 320                               sch->schid.ssid, sch->schid.sch_no, ret);
 321                 return ret;
 322         }
 323         if (!sch->driver) {
 324                 /*
 325                  * No driver matched. Generate the uevent now so that
 326                  * a fitting driver module may be loaded based on the
 327                  * modalias.
 328                  */
 329                 dev_set_uevent_suppress(&sch->dev, 0);
 330                 kobject_uevent(&sch->dev.kobj, KOBJ_ADD);
 331         }
 332         return ret;
 333 }
 334
 335 static int css_probe_device(struct subchannel_id schid)
 336 {
 337         struct subchannel *sch;
 338         int ret;
 339
 340         sch = css_alloc_subchannel(schid);
 341         if (IS_ERR(sch))
 342                 return PTR_ERR(sch);
 343
 344         ret = css_register_subchannel(sch);
 345         if (ret)
 346                 put_device(&sch->dev);
 347
 348         return ret;
 349 }
 350
 351 static int
 352 check_subchannel(struct device * dev, void * data)
 353 {
 354         struct subchannel *sch;
 355         struct subchannel_id *schid = data;
 356
 357         sch = to_subchannel(dev);
 358         return schid_equal(&sch->schid, schid);
 359 }
 360
 361 struct subchannel *
 362 get_subchannel_by_schid(struct subchannel_id schid)
 363 {
 364         struct device *dev;
 365
 366         dev = bus_find_device(&css_bus_type, NULL,
 367                               &schid, check_subchannel);
 368
 369         return dev ? to_subchannel(dev) : NULL;
 370 }
 371
 372 /**
 373  * css_sch_is_valid() - check if a subchannel is valid
 374  * @schib: subchannel information block for the subchannel
 375  */
 376 int css_sch_is_valid(struct schib *schib)
 377 {
 378         if ((schib->pmcw.st == SUBCHANNEL_TYPE_IO) && !schib->pmcw.dnv)
 379                 return 0;
 380         if ((schib->pmcw.st == SUBCHANNEL_TYPE_MSG) && !schib->pmcw.w)
 381                 return 0;
 382         return 1;
 383 }
 384 EXPORT_SYMBOL_GPL(css_sch_is_valid);
 385
 386 static int css_evaluate_new_subchannel(struct subchannel_id schid, int slow)
 387 {
 388         struct schib schib;
 389
 390         if (!slow) {
 391                 /* Will be done on the slow path. */
 392                 return -EAGAIN;
 393         }
 394         if (stsch_err(schid, &schib)) {
 395                 /* Subchannel is not provided. */
 396                 return -ENXIO;
 397         }
 398         if (!css_sch_is_valid(&schib)) {
 399                 /* Unusable - ignore. */
 400                 return 0;
 401         }
 402         CIO_MSG_EVENT(4, "event: sch 0.%x.%04x, new\n", schid.ssid,
 403                       schid.sch_no);
 404
 405         return css_probe_device(schid);
 406 }
 407
 408 static int css_evaluate_known_subchannel(struct subchannel *sch, int slow)
 409 {
 410         int ret = 0;
 411
 412         if (sch->driver) {
 413                 if (sch->driver->sch_event)
 414                         ret = sch->driver->sch_event(sch, slow);
 415                 else
 416                         dev_dbg(&sch->dev,
 417                                 "Got subchannel machine check but "
 418                                 "no sch_event handler provided.\n");
 419         }
 420         if (ret != 0 && ret != -EAGAIN) {
 421                 CIO_MSG_EVENT(2, "eval: sch 0.%x.%04x, rc=%d\n",
 422                               sch->schid.ssid, sch->schid.sch_no, ret);
 423         }
 424         return ret;
 425 }
 426
 427 static void css_evaluate_subchannel(struct subchannel_id schid, int slow)
 428 {
 429         struct subchannel *sch;
 430         int ret;
 431
 432         sch = get_subchannel_by_schid(schid);
 433         if (sch) {
 434                 ret = css_evaluate_known_subchannel(sch, slow);
 435                 put_device(&sch->dev);
 436         } else
 437                 ret = css_evaluate_new_subchannel(schid, slow);
 438         if (ret == -EAGAIN)
 439                 css_schedule_eval(schid);
 440 }
 441
 442 /**
 443  * css_sched_sch_todo - schedule a subchannel operation
 444  * @sch: subchannel
 445  * @todo: todo
 446  *
 447  * Schedule the operation identified by @todo to be performed on the slow path
 448  * workqueue. Do nothing if another operation with higher priority is already
 449  * scheduled. Needs to be called with subchannel lock held.
 450  */
 451 void css_sched_sch_todo(struct subchannel *sch, enum sch_todo todo)
 452 {
 453         CIO_MSG_EVENT(4, "sch_todo: sched sch=0.%x.%04x todo=%d\n",
 454                       sch->schid.ssid, sch->schid.sch_no, todo);
 455         if (sch->todo >= todo)
 456                 return;
 457         /* Get workqueue ref. */
 458         if (!get_device(&sch->dev))
 459                 return;
 460         sch->todo = todo;
 461         if (!queue_work(cio_work_q, &sch->todo_work)) {
 462                 /* Already queued, release workqueue ref. */
 463                 put_device(&sch->dev);
 464         }
 465 }
 466 EXPORT_SYMBOL_GPL(css_sched_sch_todo);
 467
 468 static void css_sch_todo(struct work_struct *work)
 469 {
 470         struct subchannel *sch;
 471         enum sch_todo todo;
 472         int ret;
 473
 474         sch = container_of(work, struct subchannel, todo_work);
 475         /* Find out todo. */
 476         spin_lock_irq(sch->lock);
 477         todo = sch->todo;
 478         CIO_MSG_EVENT(4, "sch_todo: sch=0.%x.%04x, todo=%d\n", sch->schid.ssid,
 479                       sch->schid.sch_no, todo);
 480         sch->todo = SCH_TODO_NOTHING;
 481         spin_unlock_irq(sch->lock);
 482         /* Perform todo. */
 483         switch (todo) {
 484         case SCH_TODO_NOTHING:
 485                 break;
 486         case SCH_TODO_EVAL:
 487                 ret = css_evaluate_known_subchannel(sch, 1);
 488                 if (ret == -EAGAIN) {
 489                         spin_lock_irq(sch->lock);
 490                         css_sched_sch_todo(sch, todo);
 491                         spin_unlock_irq(sch->lock);
 492                 }
 493                 break;
 494         case SCH_TODO_UNREG:
 495                 css_sch_device_unregister(sch);
 496                 break;
 497         }
 498         /* Release workqueue ref. */
 499         put_device(&sch->dev);
 500 }
 501
 502 static struct idset *slow_subchannel_set;
 503 static spinlock_t slow_subchannel_lock;
 504 static wait_queue_head_t css_eval_wq;
 505 static atomic_t css_eval_scheduled;
 506
 507 static int __init slow_subchannel_init(void)
 508 {
 509         spin_lock_init(&slow_subchannel_lock);
 510         atomic_set(&css_eval_scheduled, 0);
 511         init_waitqueue_head(&css_eval_wq);
 512         slow_subchannel_set = idset_sch_new();
 513         if (!slow_subchannel_set) {
 514                 CIO_MSG_EVENT(0, "could not allocate slow subchannel set\n");
 515                 return -ENOMEM;
 516         }
 517         return 0;
 518 }
 519
 520 static int slow_eval_known_fn(struct subchannel *sch, void *data)
 521 {
 522         int eval;
 523         int rc;
 524
 525         spin_lock_irq(&slow_subchannel_lock);
 526         eval = idset_sch_contains(slow_subchannel_set, sch->schid);
 527         idset_sch_del(slow_subchannel_set, sch->schid);
 528         spin_unlock_irq(&slow_subchannel_lock);
 529         if (eval) {
 530                 rc = css_evaluate_known_subchannel(sch, 1);
 531                 if (rc == -EAGAIN)
 532                         css_schedule_eval(sch->schid);
 533         }
 534         return 0;
 535 }
 536
 537 static int slow_eval_unknown_fn(struct subchannel_id schid, void *data)
 538 {
 539         int eval;
 540         int rc = 0;
 541
 542         spin_lock_irq(&slow_subchannel_lock);
 543         eval = idset_sch_contains(slow_subchannel_set, schid);
 544         idset_sch_del(slow_subchannel_set, schid);
 545         spin_unlock_irq(&slow_subchannel_lock);
 546         if (eval) {
 547                 rc = css_evaluate_new_subchannel(schid, 1);
 548                 switch (rc) {
 549                 case -EAGAIN:
 550                         css_schedule_eval(schid);
 551                         rc = 0;
 552                         break;
 553                 case -ENXIO:
 554                 case -ENOMEM:
 555                 case -EIO:
 556                         /* These should abort looping */
 557                         spin_lock_irq(&slow_subchannel_lock);
 558                         idset_sch_del_subseq(slow_subchannel_set, schid);
 559                         spin_unlock_irq(&slow_subchannel_lock);
 560                         break;
 561                 default:
 562                         rc = 0;
 563                 }
 564                 /* Allow scheduling here since the containing loop might
 565                  * take a while.  */
 566                 cond_resched();
 567         }
 568         return rc;
 569 }
 570
 571 static void css_slow_path_func(struct work_struct *unused)
 572 {
 573         unsigned long flags;
 574
 575         CIO_TRACE_EVENT(4, "slowpath");
 576         for_each_subchannel_staged(slow_eval_known_fn, slow_eval_unknown_fn,
 577                                    NULL);
 578         spin_lock_irqsave(&slow_subchannel_lock, flags);
 579         if (idset_is_empty(slow_subchannel_set)) {
 580                 atomic_set(&css_eval_scheduled, 0);
 581                 wake_up(&css_eval_wq);
 582         }
 583         spin_unlock_irqrestore(&slow_subchannel_lock, flags);
 584 }
 585
 586 static DECLARE_DELAYED_WORK(slow_path_work, css_slow_path_func);
 587 struct workqueue_struct *cio_work_q;
 588
 589 void css_schedule_eval(struct subchannel_id schid)
 590 {
 591         unsigned long flags;
 592
 593         spin_lock_irqsave(&slow_subchannel_lock, flags);
 594         idset_sch_add(slow_subchannel_set, schid);
 595         atomic_set(&css_eval_scheduled, 1);
 596         queue_delayed_work(cio_work_q, &slow_path_work, 0);
 597         spin_unlock_irqrestore(&slow_subchannel_lock, flags);
 598 }
 599
 600 void css_schedule_eval_all(void)
 601 {
 602         unsigned long flags;
 603
 604         spin_lock_irqsave(&slow_subchannel_lock, flags);
 605         idset_fill(slow_subchannel_set);
 606         atomic_set(&css_eval_scheduled, 1);
 607         queue_delayed_work(cio_work_q, &slow_path_work, 0);
 608         spin_unlock_irqrestore(&slow_subchannel_lock, flags);
 609 }
 610
 611 static int __unset_registered(struct device *dev, void *data)
 612 {
 613         struct idset *set = data;
 614         struct subchannel *sch = to_subchannel(dev);
 615
 616         idset_sch_del(set, sch->schid);
 617         return 0;
 618 }
 619
 620 void css_schedule_eval_all_unreg(unsigned long delay)
 621 {
 622         unsigned long flags;
 623         struct idset *unreg_set;
 624
 625         /* Find unregistered subchannels. */
 626         unreg_set = idset_sch_new();
 627         if (!unreg_set) {
 628                 /* Fallback. */
 629                 css_schedule_eval_all();
 630                 return;
 631         }
 632         idset_fill(unreg_set);
 633         bus_for_each_dev(&css_bus_type, NULL, unreg_set, __unset_registered);
 634         /* Apply to slow_subchannel_set. */
 635         spin_lock_irqsave(&slow_subchannel_lock, flags);
 636         idset_add_set(slow_subchannel_set, unreg_set);
 637         atomic_set(&css_eval_scheduled, 1);
 638         queue_delayed_work(cio_work_q, &slow_path_work, delay);
 639         spin_unlock_irqrestore(&slow_subchannel_lock, flags);
 640         idset_free(unreg_set);
 641 }
 642
 643 void css_wait_for_slow_path(void)
 644 {
 645         flush_workqueue(cio_work_q);
 646 }
 647
 648 /* Schedule reprobing of all unregistered subchannels. */
 649 void css_schedule_reprobe(void)
 650 {
 651         /* Schedule with a delay to allow merging of subsequent calls. */
 652         css_schedule_eval_all_unreg(1 * HZ);
 653 }
 654 EXPORT_SYMBOL_GPL(css_schedule_reprobe);
 655
 656 /*
 657  * Called from the machine check handler for subchannel report words.
 658  */
 659 static void css_process_crw(struct crw *crw0, struct crw *crw1, int overflow)
 660 {
 661         struct subchannel_id mchk_schid;
 662         struct subchannel *sch;
 663
 664         if (overflow) {
 665                 css_schedule_eval_all();
 666                 return;
 667         }
 668         CIO_CRW_EVENT(2, "CRW0 reports slct=%d, oflw=%d, "
 669                       "chn=%d, rsc=%X, anc=%d, erc=%X, rsid=%X\n",
 670                       crw0->slct, crw0->oflw, crw0->chn, crw0->rsc, crw0->anc,
 671                       crw0->erc, crw0->rsid);
 672         if (crw1)
 673                 CIO_CRW_EVENT(2, "CRW1 reports slct=%d, oflw=%d, "
 674                               "chn=%d, rsc=%X, anc=%d, erc=%X, rsid=%X\n",
 675                               crw1->slct, crw1->oflw, crw1->chn, crw1->rsc,
 676                               crw1->anc, crw1->erc, crw1->rsid);
 677         init_subchannel_id(&mchk_schid);
 678         mchk_schid.sch_no = crw0->rsid;
 679         if (crw1)
 680                 mchk_schid.ssid = (crw1->rsid >> 4) & 3;
 681
 682         if (crw0->erc == CRW_ERC_PMOD) {
 683                 sch = get_subchannel_by_schid(mchk_schid);
 684                 if (sch) {
 685                         css_update_ssd_info(sch);
 686                         put_device(&sch->dev);
 687                 }
 688         }
 689         /*
 690          * Since we are always presented with IPI in the CRW, we have to
 691          * use stsch() to find out if the subchannel in question has come
 692          * or gone.
 693          */
 694         css_evaluate_subchannel(mchk_schid, 0);
 695 }
 696
 697 static void __init
 698 css_generate_pgid(struct channel_subsystem *css, u32 tod_high)
 699 {
 700         struct cpuid cpu_id;
 701
 702         if (css_general_characteristics.mcss) {
 703                 css->global_pgid.pgid_high.ext_cssid.version = 0x80;
 704                 css->global_pgid.pgid_high.ext_cssid.cssid = css->cssid;
 705         } else {
 706 #ifdef CONFIG_SMP
 707                 css->global_pgid.pgid_high.cpu_addr = stap();
 708 #else
 709                 css->global_pgid.pgid_high.cpu_addr = 0;
 710 #endif
 711         }
 712         get_cpu_id(&cpu_id);
 713         css->global_pgid.cpu_id = cpu_id.ident;
 714         css->global_pgid.cpu_model = cpu_id.machine;
 715         css->global_pgid.tod_high = tod_high;
 716
 717 }
 718
 719 static void
 720 channel_subsystem_release(struct device *dev)
 721 {
 722         struct channel_subsystem *css;
 723
 724         css = to_css(dev);
 725         mutex_destroy(&css->mutex);
 726         if (css->pseudo_subchannel) {
 727                 /* Implies that it has been generated but never registered. */
 728                 css_subchannel_release(&css->pseudo_subchannel->dev);
 729                 css->pseudo_subchannel = NULL;
 730         }
 731         kfree(css);
 732 }
 733
 734 static ssize_t
 735 css_cm_enable_show(struct device *dev, struct device_attribute *attr,
 736                    char *buf)
 737 {
 738         struct channel_subsystem *css = to_css(dev);
 739         int ret;
 740
 741         if (!css)
 742                 return 0;
 743         mutex_lock(&css->mutex);
 744         ret = sprintf(buf, "%x\n", css->cm_enabled);
 745         mutex_unlock(&css->mutex);
 746         return ret;
 747 }
 748
 749 static ssize_t
 750 css_cm_enable_store(struct device *dev, struct device_attribute *attr,
 751                     const char *buf, size_t count)
 752 {
 753         struct channel_subsystem *css = to_css(dev);
 754         int ret;
 755         unsigned long val;
 756
 757         ret = kstrtoul(buf, 16, &val);
 758         if (ret)
 759                 return ret;
 760         mutex_lock(&css->mutex);
 761         switch (val) {
 762         case 0:
 763                 ret = css->cm_enabled ? chsc_secm(css, 0) : 0;
 764                 break;
 765         case 1:
 766                 ret = css->cm_enabled ? 0 : chsc_secm(css, 1);
 767                 break;
 768         default:
 769                 ret = -EINVAL;
 770         }
 771         mutex_unlock(&css->mutex);
 772         return ret < 0 ? ret : count;
 773 }
 774
 775 static DEVICE_ATTR(cm_enable, 0644, css_cm_enable_show, css_cm_enable_store);
 776
 777 static int __init setup_css(int nr)
 778 {
 779         u32 tod_high;
 780         int ret;
 781         struct channel_subsystem *css;
 782
 783         css = channel_subsystems[nr];
 784         memset(css, 0, sizeof(struct channel_subsystem));
 785         css->pseudo_subchannel =
 786                 kzalloc(sizeof(*css->pseudo_subchannel), GFP_KERNEL);
 787         if (!css->pseudo_subchannel)
 788                 return -ENOMEM;
 789         css->pseudo_subchannel->dev.parent = &css->device;
 790         css->pseudo_subchannel->dev.release = css_subchannel_release;
 791         dev_set_name(&css->pseudo_subchannel->dev, "defunct");
 792         mutex_init(&css->pseudo_subchannel->reg_mutex);
 793         ret = css_sch_create_locks(css->pseudo_subchannel);
 794         if (ret) {
 795                 kfree(css->pseudo_subchannel);
 796                 return ret;
 797         }
 798         mutex_init(&css->mutex);
 799         css->valid = 1;
 800         css->cssid = nr;
 801         dev_set_name(&css->device, "css%x", nr);
 802         css->device.release = channel_subsystem_release;
 803         tod_high = (u32) (get_tod_clock() >> 32);
 804         css_generate_pgid(css, tod_high);
 805         return 0;
 806 }
 807
 808 static int css_reboot_event(struct notifier_block *this,
 809                             unsigned long event,
 810                             void *ptr)
 811 {
 812         int ret, i;
 813
 814         ret = NOTIFY_DONE;
 815         for (i = 0; i <= __MAX_CSSID; i++) {
 816                 struct channel_subsystem *css;
 817
 818                 css = channel_subsystems[i];
 819                 mutex_lock(&css->mutex);
 820                 if (css->cm_enabled)
 821                         if (chsc_secm(css, 0))
 822                                 ret = NOTIFY_BAD;
 823                 mutex_unlock(&css->mutex);
 824         }
 825
 826         return ret;
 827 }
 828
 829 static struct notifier_block css_reboot_notifier = {
 830         .notifier_call = css_reboot_event,
 831 };
 832
 833 /*
 834  * Since the css devices are neither on a bus nor have a class
 835  * nor have a special device type, we cannot stop/restart channel
 836  * path measurements via the normal suspend/resume callbacks, but have
 837  * to use notifiers.
 838  */
 839 static int css_power_event(struct notifier_block *this, unsigned long event,
 840                            void *ptr)
 841 {
 842         int ret, i;
 843
 844         switch (event) {
 845         case PM_HIBERNATION_PREPARE:
 846         case PM_SUSPEND_PREPARE:
 847                 ret = NOTIFY_DONE;
 848                 for (i = 0; i <= __MAX_CSSID; i++) {
 849                         struct channel_subsystem *css;
 850
 851                         css = channel_subsystems[i];
 852                         mutex_lock(&css->mutex);
 853                         if (!css->cm_enabled) {
 854                                 mutex_unlock(&css->mutex);
 855                                 continue;
 856                         }
 857                         ret = __chsc_do_secm(css, 0);
 858                         ret = notifier_from_errno(ret);
 859                         mutex_unlock(&css->mutex);
 860                 }
 861                 break;
 862         case PM_POST_HIBERNATION:
 863         case PM_POST_SUSPEND:
 864                 ret = NOTIFY_DONE;
 865                 for (i = 0; i <= __MAX_CSSID; i++) {
 866                         struct channel_subsystem *css;
 867
 868                         css = channel_subsystems[i];
 869                         mutex_lock(&css->mutex);
 870                         if (!css->cm_enabled) {
 871                                 mutex_unlock(&css->mutex);
 872                                 continue;
 873                         }
 874                         ret = __chsc_do_secm(css, 1);
 875                         ret = notifier_from_errno(ret);
 876                         mutex_unlock(&css->mutex);
 877                 }
 878                 /* search for subchannels, which appeared during hibernation */
 879                 css_schedule_reprobe();
 880                 break;
 881         default:
 882                 ret = NOTIFY_DONE;
 883         }
 884         return ret;
 885
 886 }
 887 static struct notifier_block css_power_notifier = {
 888         .notifier_call = css_power_event,
 889 };
 890
 891 /*
 892  * Now that the driver core is running, we can setup our channel subsystem.
 893  * The struct subchannel's are created during probing.
 894  */
 895 static int __init css_bus_init(void)
 896 {
 897         int ret, i;
 898
 899         ret = chsc_init();
 900         if (ret)
 901                 return ret;
 902
 903         chsc_determine_css_characteristics();
 904         /* Try to enable MSS. */
 905         ret = chsc_enable_facility(CHSC_SDA_OC_MSS);
 906         if (ret)
 907                 max_ssid = 0;
 908         else /* Success. */
 909                 max_ssid = __MAX_SSID;
 910
 911         ret = slow_subchannel_init();
 912         if (ret)
 913                 goto out;
 914
 915         ret = crw_register_handler(CRW_RSC_SCH, css_process_crw);
 916         if (ret)
 917                 goto out;
 918
 919         if ((ret = bus_register(&css_bus_type)))
 920                 goto out;
 921
 922         /* Setup css structure. */
 923         for (i = 0; i <= __MAX_CSSID; i++) {
 924                 struct channel_subsystem *css;
 925
 926                 css = kmalloc(sizeof(struct channel_subsystem), GFP_KERNEL);
 927                 if (!css) {
 928                         ret = -ENOMEM;
 929                         goto out_unregister;
 930                 }
 931                 channel_subsystems[i] = css;
 932                 ret = setup_css(i);
 933                 if (ret) {
 934                         kfree(channel_subsystems[i]);
 935                         goto out_unregister;
 936                 }
 937                 ret = device_register(&css->device);
 938                 if (ret) {
 939                         put_device(&css->device);
 940                         goto out_unregister;
 941                 }
 942                 if (css_chsc_characteristics.secm) {
 943                         ret = device_create_file(&css->device,
 944                                                  &dev_attr_cm_enable);
 945                         if (ret)
 946                                 goto out_device;
 947                 }
 948                 ret = device_register(&css->pseudo_subchannel->dev);
 949                 if (ret) {
 950                         put_device(&css->pseudo_subchannel->dev);
 951                         goto out_file;
 952                 }
 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_file:
 969         if (css_chsc_characteristics.secm)
 970                 device_remove_file(&channel_subsystems[i]->device,
 971                                    &dev_attr_cm_enable);
 972 out_device:
 973         device_unregister(&channel_subsystems[i]->device);
 974 out_unregister:
 975         while (i > 0) {
 976                 struct channel_subsystem *css;
 977
 978                 i--;
 979                 css = channel_subsystems[i];
 980                 device_unregister(&css->pseudo_subchannel->dev);
 981                 css->pseudo_subchannel = NULL;
 982                 if (css_chsc_characteristics.secm)
 983                         device_remove_file(&css->device,
 984                                            &dev_attr_cm_enable);
 985                 device_unregister(&css->device);
 986         }
 987         bus_unregister(&css_bus_type);
 988 out:
 989         crw_unregister_handler(CRW_RSC_SCH);
 990         idset_free(slow_subchannel_set);
 991         chsc_init_cleanup();
 992         pr_alert("The CSS device driver initialization failed with "
 993                  "errno=%d\n", ret);
 994         return ret;
 995 }
 996
 997 static void __init css_bus_cleanup(void)
 998 {
 999         struct channel_subsystem *css;
1000         int i;
1001
1002         for (i = 0; i <= __MAX_CSSID; i++) {
1003                 css = channel_subsystems[i];
1004                 device_unregister(&css->pseudo_subchannel->dev);
1005                 css->pseudo_subchannel = NULL;
1006                 if (css_chsc_characteristics.secm)
1007                         device_remove_file(&css->device, &dev_attr_cm_enable);
1008                 device_unregister(&css->device);
1009         }
1010         bus_unregister(&css_bus_type);
1011         crw_unregister_handler(CRW_RSC_SCH);
1012         idset_free(slow_subchannel_set);
1013         chsc_init_cleanup();
1014         isc_unregister(IO_SCH_ISC);
1015 }
1016
1017 static int __init channel_subsystem_init(void)
1018 {
1019         int ret;
1020
1021         ret = css_bus_init();
1022         if (ret)
1023                 return ret;
1024         cio_work_q = create_singlethread_workqueue("cio");
1025         if (!cio_work_q) {
1026                 ret = -ENOMEM;
1027                 goto out_bus;
1028         }
1029         ret = io_subchannel_init();
1030         if (ret)
1031                 goto out_wq;
1032
1033         return ret;
1034 out_wq:
1035         destroy_workqueue(cio_work_q);
1036 out_bus:
1037         css_bus_cleanup();
1038         return ret;
1039 }
1040 subsys_initcall(channel_subsystem_init);
1041
1042 static int css_settle(struct device_driver *drv, void *unused)
1043 {
1044         struct css_driver *cssdrv = to_cssdriver(drv);
1045
1046         if (cssdrv->settle)
1047                 return cssdrv->settle();
1048         return 0;
1049 }
1050
1051 int css_complete_work(void)
1052 {
1053         int ret;
1054
1055         /* Wait for the evaluation of subchannels to finish. */
1056         ret = wait_event_interruptible(css_eval_wq,
1057                                        atomic_read(&css_eval_scheduled) == 0);
1058         if (ret)
1059                 return -EINTR;
1060         flush_workqueue(cio_work_q);
1061         /* Wait for the subchannel type specific initialization to finish */
1062         return bus_for_each_drv(&css_bus_type, NULL, NULL, css_settle);
1063 }
1064
1065
1066 /*
1067  * Wait for the initialization of devices to finish, to make sure we are
1068  * done with our setup if the search for the root device starts.
1069  */
1070 static int __init channel_subsystem_init_sync(void)
1071 {
1072         /* Register subchannels which are already in use. */
1073         cio_register_early_subchannels();
1074         /* Start initial subchannel evaluation. */
1075         css_schedule_eval_all();
1076         css_complete_work();
1077         return 0;
1078 }
1079 subsys_initcall_sync(channel_subsystem_init_sync);
1080
1081 void channel_subsystem_reinit(void)
1082 {
1083         struct channel_path *chp;
1084         struct chp_id chpid;
1085
1086         chsc_enable_facility(CHSC_SDA_OC_MSS);
1087         chp_id_for_each(&chpid) {
1088                 chp = chpid_to_chp(chpid);
1089                 if (chp)
1090                         chp_update_desc(chp);
1091         }
1092 }
1093
1094 #ifdef CONFIG_PROC_FS
1095 static ssize_t cio_settle_write(struct file *file, const char __user *buf,
1096                                 size_t count, loff_t *ppos)
1097 {
1098         int ret;
1099
1100         /* Handle pending CRW's. */
1101         crw_wait_for_channel_report();
1102         ret = css_complete_work();
1103
1104         return ret ? ret : count;
1105 }
1106
1107 static const struct file_operations cio_settle_proc_fops = {
1108         .open = nonseekable_open,
1109         .write = cio_settle_write,
1110         .llseek = no_llseek,
1111 };
1112
1113 static int __init cio_settle_init(void)
1114 {
1115         struct proc_dir_entry *entry;
1116
1117         entry = proc_create("cio_settle", S_IWUSR, NULL,
1118                             &cio_settle_proc_fops);
1119         if (!entry)
1120                 return -ENOMEM;
1121         return 0;
1122 }
1123 device_initcall(cio_settle_init);
1124 #endif /*CONFIG_PROC_FS*/
1125
1126 int sch_is_pseudo_sch(struct subchannel *sch)
1127 {
1128         return sch == to_css(sch->dev.parent)->pseudo_subchannel;
1129 }
1130
1131 static int css_bus_match(struct device *dev, struct device_driver *drv)
1132 {
1133         struct subchannel *sch = to_subchannel(dev);
1134         struct css_driver *driver = to_cssdriver(drv);
1135         struct css_device_id *id;
1136
1137         for (id = driver->subchannel_type; id->match_flags; id++) {
1138                 if (sch->st == id->type)
1139                         return 1;
1140         }
1141
1142         return 0;
1143 }
1144
1145 static int css_probe(struct device *dev)
1146 {
1147         struct subchannel *sch;
1148         int ret;
1149
1150         sch = to_subchannel(dev);
1151         sch->driver = to_cssdriver(dev->driver);
1152         ret = sch->driver->probe ? sch->driver->probe(sch) : 0;
1153         if (ret)
1154                 sch->driver = NULL;
1155         return ret;
1156 }
1157
1158 static int css_remove(struct device *dev)
1159 {
1160         struct subchannel *sch;
1161         int ret;
1162
1163         sch = to_subchannel(dev);
1164         ret = sch->driver->remove ? sch->driver->remove(sch) : 0;
1165         sch->driver = NULL;
1166         return ret;
1167 }
1168
1169 static void css_shutdown(struct device *dev)
1170 {
1171         struct subchannel *sch;
1172
1173         sch = to_subchannel(dev);
1174         if (sch->driver && sch->driver->shutdown)
1175                 sch->driver->shutdown(sch);
1176 }
1177
1178 static int css_uevent(struct device *dev, struct kobj_uevent_env *env)
1179 {
1180         struct subchannel *sch = to_subchannel(dev);
1181         int ret;
1182
1183         ret = add_uevent_var(env, "ST=%01X", sch->st);
1184         if (ret)
1185                 return ret;
1186         ret = add_uevent_var(env, "MODALIAS=css:t%01X", sch->st);
1187         return ret;
1188 }
1189
1190 static int css_pm_prepare(struct device *dev)
1191 {
1192         struct subchannel *sch = to_subchannel(dev);
1193         struct css_driver *drv;
1194
1195         if (mutex_is_locked(&sch->reg_mutex))
1196                 return -EAGAIN;
1197         if (!sch->dev.driver)
1198                 return 0;
1199         drv = to_cssdriver(sch->dev.driver);
1200         /* Notify drivers that they may not register children. */
1201         return drv->prepare ? drv->prepare(sch) : 0;
1202 }
1203
1204 static void css_pm_complete(struct device *dev)
1205 {
1206         struct subchannel *sch = to_subchannel(dev);
1207         struct css_driver *drv;
1208
1209         if (!sch->dev.driver)
1210                 return;
1211         drv = to_cssdriver(sch->dev.driver);
1212         if (drv->complete)
1213                 drv->complete(sch);
1214 }
1215
1216 static int css_pm_freeze(struct device *dev)
1217 {
1218         struct subchannel *sch = to_subchannel(dev);
1219         struct css_driver *drv;
1220
1221         if (!sch->dev.driver)
1222                 return 0;
1223         drv = to_cssdriver(sch->dev.driver);
1224         return drv->freeze ? drv->freeze(sch) : 0;
1225 }
1226
1227 static int css_pm_thaw(struct device *dev)
1228 {
1229         struct subchannel *sch = to_subchannel(dev);
1230         struct css_driver *drv;
1231
1232         if (!sch->dev.driver)
1233                 return 0;
1234         drv = to_cssdriver(sch->dev.driver);
1235         return drv->thaw ? drv->thaw(sch) : 0;
1236 }
1237
1238 static int css_pm_restore(struct device *dev)
1239 {
1240         struct subchannel *sch = to_subchannel(dev);
1241         struct css_driver *drv;
1242
1243         css_update_ssd_info(sch);
1244         if (!sch->dev.driver)
1245                 return 0;
1246         drv = to_cssdriver(sch->dev.driver);
1247         return drv->restore ? drv->restore(sch) : 0;
1248 }
1249
1250 static const struct dev_pm_ops css_pm_ops = {
1251         .prepare = css_pm_prepare,
1252         .complete = css_pm_complete,
1253         .freeze = css_pm_freeze,
1254         .thaw = css_pm_thaw,
1255         .restore = css_pm_restore,
1256 };
1257
1258 static struct bus_type css_bus_type = {
1259         .name     = "css",
1260         .match    = css_bus_match,
1261         .probe    = css_probe,
1262         .remove   = css_remove,
1263         .shutdown = css_shutdown,
1264         .uevent   = css_uevent,
1265         .pm = &css_pm_ops,
1266 };
1267
1268 /**
1269  * css_driver_register - register a css driver
1270  * @cdrv: css driver to register
1271  *
1272  * This is mainly a wrapper around driver_register that sets name
1273  * and bus_type in the embedded struct device_driver correctly.
1274  */
1275 int css_driver_register(struct css_driver *cdrv)
1276 {
1277         cdrv->drv.bus = &css_bus_type;
1278         return driver_register(&cdrv->drv);
1279 }
1280 EXPORT_SYMBOL_GPL(css_driver_register);
1281
1282 /**
1283  * css_driver_unregister - unregister a css driver
1284  * @cdrv: css driver to unregister
1285  *
1286  * This is a wrapper around driver_unregister.
1287  */
1288 void css_driver_unregister(struct css_driver *cdrv)
1289 {
1290         driver_unregister(&cdrv->drv);
1291 }
1292 EXPORT_SYMBOL_GPL(css_driver_unregister);
1293
1294 MODULE_LICENSE("GPL");