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         do {
  48                 do {
  49                         ret = fn(schid, data);
  50                         if (ret)
  51                                 break;
  52                 } while (schid.sch_no++ < __MAX_SUBCHANNEL);
  53                 schid.sch_no = 0;
  54         } while (schid.ssid++ < max_ssid);
  55         return ret;
  56 }
  57
  58 struct cb_data {
  59         void *data;
  60         struct idset *set;
  61         int (*fn_known_sch)(struct subchannel *, void *);
  62         int (*fn_unknown_sch)(struct subchannel_id, void *);
  63 };
  64
  65 static int call_fn_known_sch(struct device *dev, void *data)
  66 {
  67         struct subchannel *sch = to_subchannel(dev);
  68         struct cb_data *cb = data;
  69         int rc = 0;
  70
  71         if (cb->set)
  72                 idset_sch_del(cb->set, sch->schid);
  73         if (cb->fn_known_sch)
  74                 rc = cb->fn_known_sch(sch, cb->data);
  75         return rc;
  76 }
  77
  78 static int call_fn_unknown_sch(struct subchannel_id schid, void *data)
  79 {
  80         struct cb_data *cb = data;
  81         int rc = 0;
  82
  83         if (idset_sch_contains(cb->set, schid))
  84                 rc = cb->fn_unknown_sch(schid, cb->data);
  85         return rc;
  86 }
  87
  88 static int call_fn_all_sch(struct subchannel_id schid, void *data)
  89 {
  90         struct cb_data *cb = data;
  91         struct subchannel *sch;
  92         int rc = 0;
  93
  94         sch = get_subchannel_by_schid(schid);
  95         if (sch) {
  96                 if (cb->fn_known_sch)
  97                         rc = cb->fn_known_sch(sch, cb->data);
  98                 put_device(&sch->dev);
  99         } else {
 100                 if (cb->fn_unknown_sch)
 101                         rc = cb->fn_unknown_sch(schid, cb->data);
 102         }
 103
 104         return rc;
 105 }
 106
 107 int for_each_subchannel_staged(int (*fn_known)(struct subchannel *, void *),
 108                                int (*fn_unknown)(struct subchannel_id,
 109                                void *), void *data)
 110 {
 111         struct cb_data cb;
 112         int rc;
 113
 114         cb.data = data;
 115         cb.fn_known_sch = fn_known;
 116         cb.fn_unknown_sch = fn_unknown;
 117
 118         if (fn_known && !fn_unknown) {
 119                 /* Skip idset allocation in case of known-only loop. */
 120                 cb.set = NULL;
 121                 return bus_for_each_dev(&css_bus_type, NULL, &cb,
 122                                         call_fn_known_sch);
 123         }
 124
 125         cb.set = idset_sch_new();
 126         if (!cb.set)
 127                 /* fall back to brute force scanning in case of oom */
 128                 return for_each_subchannel(call_fn_all_sch, &cb);
 129
 130         idset_fill(cb.set);
 131
 132         /* Process registered subchannels. */
 133         rc = bus_for_each_dev(&css_bus_type, NULL, &cb, call_fn_known_sch);
 134         if (rc)
 135                 goto out;
 136         /* Process unregistered subchannels. */
 137         if (fn_unknown)
 138                 rc = for_each_subchannel(call_fn_unknown_sch, &cb);
 139 out:
 140         idset_free(cb.set);
 141
 142         return rc;
 143 }
 144
 145 static void css_sch_todo(struct work_struct *work);
 146
 147 static int css_sch_create_locks(struct subchannel *sch)
 148 {
 149         sch->lock = kmalloc(sizeof(*sch->lock), GFP_KERNEL);
 150         if (!sch->lock)
 151                 return -ENOMEM;
 152
 153         spin_lock_init(sch->lock);
 154         mutex_init(&sch->reg_mutex);
 155
 156         return 0;
 157 }
 158
 159 static void css_subchannel_release(struct device *dev)
 160 {
 161         struct subchannel *sch = to_subchannel(dev);
 162
 163         sch->config.intparm = 0;
 164         cio_commit_config(sch);
 165         kfree(sch->lock);
 166         kfree(sch);
 167 }
 168
 169 struct subchannel *css_alloc_subchannel(struct subchannel_id schid)
 170 {
 171         struct subchannel *sch;
 172         int ret;
 173
 174         sch = kzalloc(sizeof(*sch), GFP_KERNEL | GFP_DMA);
 175         if (!sch)
 176                 return ERR_PTR(-ENOMEM);
 177
 178         ret = cio_validate_subchannel(sch, schid);
 179         if (ret < 0)
 180                 goto err;
 181
 182         ret = css_sch_create_locks(sch);
 183         if (ret)
 184                 goto err;
 185
 186         INIT_WORK(&sch->todo_work, css_sch_todo);
 187         sch->dev.release = &css_subchannel_release;
 188         device_initialize(&sch->dev);
 189         return sch;
 190
 191 err:
 192         kfree(sch);
 193         return ERR_PTR(ret);
 194 }
 195
 196 static int css_sch_device_register(struct subchannel *sch)
 197 {
 198         int ret;
 199
 200         mutex_lock(&sch->reg_mutex);
 201         dev_set_name(&sch->dev, "0.%x.%04x", sch->schid.ssid,
 202                      sch->schid.sch_no);
 203         ret = device_add(&sch->dev);
 204         mutex_unlock(&sch->reg_mutex);
 205         return ret;
 206 }
 207
 208 /**
 209  * css_sch_device_unregister - unregister a subchannel
 210  * @sch: subchannel to be unregistered
 211  */
 212 void css_sch_device_unregister(struct subchannel *sch)
 213 {
 214         mutex_lock(&sch->reg_mutex);
 215         if (device_is_registered(&sch->dev))
 216                 device_unregister(&sch->dev);
 217         mutex_unlock(&sch->reg_mutex);
 218 }
 219 EXPORT_SYMBOL_GPL(css_sch_device_unregister);
 220
 221 static void ssd_from_pmcw(struct chsc_ssd_info *ssd, struct pmcw *pmcw)
 222 {
 223         int i;
 224         int mask;
 225
 226         memset(ssd, 0, sizeof(struct chsc_ssd_info));
 227         ssd->path_mask = pmcw->pim;
 228         for (i = 0; i < 8; i++) {
 229                 mask = 0x80 >> i;
 230                 if (pmcw->pim & mask) {
 231                         chp_id_init(&ssd->chpid[i]);
 232                         ssd->chpid[i].id = pmcw->chpid[i];
 233                 }
 234         }
 235 }
 236
 237 static void ssd_register_chpids(struct chsc_ssd_info *ssd)
 238 {
 239         int i;
 240         int mask;
 241
 242         for (i = 0; i < 8; i++) {
 243                 mask = 0x80 >> i;
 244                 if (ssd->path_mask & mask)
 245                         if (!chp_is_registered(ssd->chpid[i]))
 246                                 chp_new(ssd->chpid[i]);
 247         }
 248 }
 249
 250 void css_update_ssd_info(struct subchannel *sch)
 251 {
 252         int ret;
 253
 254         ret = chsc_get_ssd_info(sch->schid, &sch->ssd_info);
 255         if (ret)
 256                 ssd_from_pmcw(&sch->ssd_info, &sch->schib.pmcw);
 257
 258         ssd_register_chpids(&sch->ssd_info);
 259 }
 260
 261 static ssize_t type_show(struct device *dev, struct device_attribute *attr,
 262                          char *buf)
 263 {
 264         struct subchannel *sch = to_subchannel(dev);
 265
 266         return sprintf(buf, "%01x\n", sch->st);
 267 }
 268
 269 static DEVICE_ATTR(type, 0444, type_show, NULL);
 270
 271 static ssize_t modalias_show(struct device *dev, struct device_attribute *attr,
 272                              char *buf)
 273 {
 274         struct subchannel *sch = to_subchannel(dev);
 275
 276         return sprintf(buf, "css:t%01X\n", sch->st);
 277 }
 278
 279 static DEVICE_ATTR(modalias, 0444, modalias_show, NULL);
 280
 281 static struct attribute *subch_attrs[] = {
 282         &dev_attr_type.attr,
 283         &dev_attr_modalias.attr,
 284         NULL,
 285 };
 286
 287 static struct attribute_group subch_attr_group = {
 288         .attrs = subch_attrs,
 289 };
 290
 291 static const struct attribute_group *default_subch_attr_groups[] = {
 292         &subch_attr_group,
 293         NULL,
 294 };
 295
 296 int css_register_subchannel(struct subchannel *sch)
 297 {
 298         int ret;
 299
 300         /* Initialize the subchannel structure */
 301         sch->dev.parent = &channel_subsystems[0]->device;
 302         sch->dev.bus = &css_bus_type;
 303         sch->dev.groups = default_subch_attr_groups;
 304         /*
 305          * We don't want to generate uevents for I/O subchannels that don't
 306          * have a working ccw device behind them since they will be
 307          * unregistered before they can be used anyway, so we delay the add
 308          * uevent until after device recognition was successful.
 309          * Note that we suppress the uevent for all subchannel types;
 310          * the subchannel driver can decide itself when it wants to inform
 311          * userspace of its existence.
 312          */
 313         dev_set_uevent_suppress(&sch->dev, 1);
 314         css_update_ssd_info(sch);
 315         /* make it known to the system */
 316         ret = css_sch_device_register(sch);
 317         if (ret) {
 318                 CIO_MSG_EVENT(0, "Could not register sch 0.%x.%04x: %d\n",
 319                               sch->schid.ssid, sch->schid.sch_no, ret);
 320                 return ret;
 321         }
 322         if (!sch->driver) {
 323                 /*
 324                  * No driver matched. Generate the uevent now so that
 325                  * a fitting driver module may be loaded based on the
 326                  * modalias.
 327                  */
 328                 dev_set_uevent_suppress(&sch->dev, 0);
 329                 kobject_uevent(&sch->dev.kobj, KOBJ_ADD);
 330         }
 331         return ret;
 332 }
 333
 334 static int css_probe_device(struct subchannel_id schid)
 335 {
 336         struct subchannel *sch;
 337         int ret;
 338
 339         sch = css_alloc_subchannel(schid);
 340         if (IS_ERR(sch))
 341                 return PTR_ERR(sch);
 342
 343         ret = css_register_subchannel(sch);
 344         if (ret)
 345                 put_device(&sch->dev);
 346
 347         return ret;
 348 }
 349
 350 static int
 351 check_subchannel(struct device * dev, void * data)
 352 {
 353         struct subchannel *sch;
 354         struct subchannel_id *schid = data;
 355
 356         sch = to_subchannel(dev);
 357         return schid_equal(&sch->schid, schid);
 358 }
 359
 360 struct subchannel *
 361 get_subchannel_by_schid(struct subchannel_id schid)
 362 {
 363         struct device *dev;
 364
 365         dev = bus_find_device(&css_bus_type, NULL,
 366                               &schid, check_subchannel);
 367
 368         return dev ? to_subchannel(dev) : NULL;
 369 }
 370
 371 /**
 372  * css_sch_is_valid() - check if a subchannel is valid
 373  * @schib: subchannel information block for the subchannel
 374  */
 375 int css_sch_is_valid(struct schib *schib)
 376 {
 377         if ((schib->pmcw.st == SUBCHANNEL_TYPE_IO) && !schib->pmcw.dnv)
 378                 return 0;
 379         if ((schib->pmcw.st == SUBCHANNEL_TYPE_MSG) && !schib->pmcw.w)
 380                 return 0;
 381         return 1;
 382 }
 383 EXPORT_SYMBOL_GPL(css_sch_is_valid);
 384
 385 static int css_evaluate_new_subchannel(struct subchannel_id schid, int slow)
 386 {
 387         struct schib schib;
 388
 389         if (!slow) {
 390                 /* Will be done on the slow path. */
 391                 return -EAGAIN;
 392         }
 393         if (stsch_err(schid, &schib)) {
 394                 /* Subchannel is not provided. */
 395                 return -ENXIO;
 396         }
 397         if (!css_sch_is_valid(&schib)) {
 398                 /* Unusable - ignore. */
 399                 return 0;
 400         }
 401         CIO_MSG_EVENT(4, "event: sch 0.%x.%04x, new\n", schid.ssid,
 402                       schid.sch_no);
 403
 404         return css_probe_device(schid);
 405 }
 406
 407 static int css_evaluate_known_subchannel(struct subchannel *sch, int slow)
 408 {
 409         int ret = 0;
 410
 411         if (sch->driver) {
 412                 if (sch->driver->sch_event)
 413                         ret = sch->driver->sch_event(sch, slow);
 414                 else
 415                         dev_dbg(&sch->dev,
 416                                 "Got subchannel machine check but "
 417                                 "no sch_event handler provided.\n");
 418         }
 419         if (ret != 0 && ret != -EAGAIN) {
 420                 CIO_MSG_EVENT(2, "eval: sch 0.%x.%04x, rc=%d\n",
 421                               sch->schid.ssid, sch->schid.sch_no, ret);
 422         }
 423         return ret;
 424 }
 425
 426 static void css_evaluate_subchannel(struct subchannel_id schid, int slow)
 427 {
 428         struct subchannel *sch;
 429         int ret;
 430
 431         sch = get_subchannel_by_schid(schid);
 432         if (sch) {
 433                 ret = css_evaluate_known_subchannel(sch, slow);
 434                 put_device(&sch->dev);
 435         } else
 436                 ret = css_evaluate_new_subchannel(schid, slow);
 437         if (ret == -EAGAIN)
 438                 css_schedule_eval(schid);
 439 }
 440
 441 /**
 442  * css_sched_sch_todo - schedule a subchannel operation
 443  * @sch: subchannel
 444  * @todo: todo
 445  *
 446  * Schedule the operation identified by @todo to be performed on the slow path
 447  * workqueue. Do nothing if another operation with higher priority is already
 448  * scheduled. Needs to be called with subchannel lock held.
 449  */
 450 void css_sched_sch_todo(struct subchannel *sch, enum sch_todo todo)
 451 {
 452         CIO_MSG_EVENT(4, "sch_todo: sched sch=0.%x.%04x todo=%d\n",
 453                       sch->schid.ssid, sch->schid.sch_no, todo);
 454         if (sch->todo >= todo)
 455                 return;
 456         /* Get workqueue ref. */
 457         if (!get_device(&sch->dev))
 458                 return;
 459         sch->todo = todo;
 460         if (!queue_work(cio_work_q, &sch->todo_work)) {
 461                 /* Already queued, release workqueue ref. */
 462                 put_device(&sch->dev);
 463         }
 464 }
 465 EXPORT_SYMBOL_GPL(css_sched_sch_todo);
 466
 467 static void css_sch_todo(struct work_struct *work)
 468 {
 469         struct subchannel *sch;
 470         enum sch_todo todo;
 471         int ret;
 472
 473         sch = container_of(work, struct subchannel, todo_work);
 474         /* Find out todo. */
 475         spin_lock_irq(sch->lock);
 476         todo = sch->todo;
 477         CIO_MSG_EVENT(4, "sch_todo: sch=0.%x.%04x, todo=%d\n", sch->schid.ssid,
 478                       sch->schid.sch_no, todo);
 479         sch->todo = SCH_TODO_NOTHING;
 480         spin_unlock_irq(sch->lock);
 481         /* Perform todo. */
 482         switch (todo) {
 483         case SCH_TODO_NOTHING:
 484                 break;
 485         case SCH_TODO_EVAL:
 486                 ret = css_evaluate_known_subchannel(sch, 1);
 487                 if (ret == -EAGAIN) {
 488                         spin_lock_irq(sch->lock);
 489                         css_sched_sch_todo(sch, todo);
 490                         spin_unlock_irq(sch->lock);
 491                 }
 492                 break;
 493         case SCH_TODO_UNREG:
 494                 css_sch_device_unregister(sch);
 495                 break;
 496         }
 497         /* Release workqueue ref. */
 498         put_device(&sch->dev);
 499 }
 500
 501 static struct idset *slow_subchannel_set;
 502 static spinlock_t slow_subchannel_lock;
 503 static wait_queue_head_t css_eval_wq;
 504 static atomic_t css_eval_scheduled;
 505
 506 static int __init slow_subchannel_init(void)
 507 {
 508         spin_lock_init(&slow_subchannel_lock);
 509         atomic_set(&css_eval_scheduled, 0);
 510         init_waitqueue_head(&css_eval_wq);
 511         slow_subchannel_set = idset_sch_new();
 512         if (!slow_subchannel_set) {
 513                 CIO_MSG_EVENT(0, "could not allocate slow subchannel set\n");
 514                 return -ENOMEM;
 515         }
 516         return 0;
 517 }
 518
 519 static int slow_eval_known_fn(struct subchannel *sch, void *data)
 520 {
 521         int eval;
 522         int rc;
 523
 524         spin_lock_irq(&slow_subchannel_lock);
 525         eval = idset_sch_contains(slow_subchannel_set, sch->schid);
 526         idset_sch_del(slow_subchannel_set, sch->schid);
 527         spin_unlock_irq(&slow_subchannel_lock);
 528         if (eval) {
 529                 rc = css_evaluate_known_subchannel(sch, 1);
 530                 if (rc == -EAGAIN)
 531                         css_schedule_eval(sch->schid);
 532                 /*
 533                  * The loop might take long time for platforms with lots of
 534                  * known devices. Allow scheduling here.
 535                  */
 536                 cond_resched();
 537         }
 538         return 0;
 539 }
 540
 541 static int slow_eval_unknown_fn(struct subchannel_id schid, void *data)
 542 {
 543         int eval;
 544         int rc = 0;
 545
 546         spin_lock_irq(&slow_subchannel_lock);
 547         eval = idset_sch_contains(slow_subchannel_set, schid);
 548         idset_sch_del(slow_subchannel_set, schid);
 549         spin_unlock_irq(&slow_subchannel_lock);
 550         if (eval) {
 551                 rc = css_evaluate_new_subchannel(schid, 1);
 552                 switch (rc) {
 553                 case -EAGAIN:
 554                         css_schedule_eval(schid);
 555                         rc = 0;
 556                         break;
 557                 case -ENXIO:
 558                 case -ENOMEM:
 559                 case -EIO:
 560                         /* These should abort looping */
 561                         spin_lock_irq(&slow_subchannel_lock);
 562                         idset_sch_del_subseq(slow_subchannel_set, schid);
 563                         spin_unlock_irq(&slow_subchannel_lock);
 564                         break;
 565                 default:
 566                         rc = 0;
 567                 }
 568                 /* Allow scheduling here since the containing loop might
 569                  * take a while.  */
 570                 cond_resched();
 571         }
 572         return rc;
 573 }
 574
 575 static void css_slow_path_func(struct work_struct *unused)
 576 {
 577         unsigned long flags;
 578
 579         CIO_TRACE_EVENT(4, "slowpath");
 580         for_each_subchannel_staged(slow_eval_known_fn, slow_eval_unknown_fn,
 581                                    NULL);
 582         spin_lock_irqsave(&slow_subchannel_lock, flags);
 583         if (idset_is_empty(slow_subchannel_set)) {
 584                 atomic_set(&css_eval_scheduled, 0);
 585                 wake_up(&css_eval_wq);
 586         }
 587         spin_unlock_irqrestore(&slow_subchannel_lock, flags);
 588 }
 589
 590 static DECLARE_DELAYED_WORK(slow_path_work, css_slow_path_func);
 591 struct workqueue_struct *cio_work_q;
 592
 593 void css_schedule_eval(struct subchannel_id schid)
 594 {
 595         unsigned long flags;
 596
 597         spin_lock_irqsave(&slow_subchannel_lock, flags);
 598         idset_sch_add(slow_subchannel_set, schid);
 599         atomic_set(&css_eval_scheduled, 1);
 600         queue_delayed_work(cio_work_q, &slow_path_work, 0);
 601         spin_unlock_irqrestore(&slow_subchannel_lock, flags);
 602 }
 603
 604 void css_schedule_eval_all(void)
 605 {
 606         unsigned long flags;
 607
 608         spin_lock_irqsave(&slow_subchannel_lock, flags);
 609         idset_fill(slow_subchannel_set);
 610         atomic_set(&css_eval_scheduled, 1);
 611         queue_delayed_work(cio_work_q, &slow_path_work, 0);
 612         spin_unlock_irqrestore(&slow_subchannel_lock, flags);
 613 }
 614
 615 static int __unset_registered(struct device *dev, void *data)
 616 {
 617         struct idset *set = data;
 618         struct subchannel *sch = to_subchannel(dev);
 619
 620         idset_sch_del(set, sch->schid);
 621         return 0;
 622 }
 623
 624 void css_schedule_eval_all_unreg(unsigned long delay)
 625 {
 626         unsigned long flags;
 627         struct idset *unreg_set;
 628
 629         /* Find unregistered subchannels. */
 630         unreg_set = idset_sch_new();
 631         if (!unreg_set) {
 632                 /* Fallback. */
 633                 css_schedule_eval_all();
 634                 return;
 635         }
 636         idset_fill(unreg_set);
 637         bus_for_each_dev(&css_bus_type, NULL, unreg_set, __unset_registered);
 638         /* Apply to slow_subchannel_set. */
 639         spin_lock_irqsave(&slow_subchannel_lock, flags);
 640         idset_add_set(slow_subchannel_set, unreg_set);
 641         atomic_set(&css_eval_scheduled, 1);
 642         queue_delayed_work(cio_work_q, &slow_path_work, delay);
 643         spin_unlock_irqrestore(&slow_subchannel_lock, flags);
 644         idset_free(unreg_set);
 645 }
 646
 647 void css_wait_for_slow_path(void)
 648 {
 649         flush_workqueue(cio_work_q);
 650 }
 651
 652 /* Schedule reprobing of all unregistered subchannels. */
 653 void css_schedule_reprobe(void)
 654 {
 655         /* Schedule with a delay to allow merging of subsequent calls. */
 656         css_schedule_eval_all_unreg(1 * HZ);
 657 }
 658 EXPORT_SYMBOL_GPL(css_schedule_reprobe);
 659
 660 /*
 661  * Called from the machine check handler for subchannel report words.
 662  */
 663 static void css_process_crw(struct crw *crw0, struct crw *crw1, int overflow)
 664 {
 665         struct subchannel_id mchk_schid;
 666         struct subchannel *sch;
 667
 668         if (overflow) {
 669                 css_schedule_eval_all();
 670                 return;
 671         }
 672         CIO_CRW_EVENT(2, "CRW0 reports slct=%d, oflw=%d, "
 673                       "chn=%d, rsc=%X, anc=%d, erc=%X, rsid=%X\n",
 674                       crw0->slct, crw0->oflw, crw0->chn, crw0->rsc, crw0->anc,
 675                       crw0->erc, crw0->rsid);
 676         if (crw1)
 677                 CIO_CRW_EVENT(2, "CRW1 reports slct=%d, oflw=%d, "
 678                               "chn=%d, rsc=%X, anc=%d, erc=%X, rsid=%X\n",
 679                               crw1->slct, crw1->oflw, crw1->chn, crw1->rsc,
 680                               crw1->anc, crw1->erc, crw1->rsid);
 681         init_subchannel_id(&mchk_schid);
 682         mchk_schid.sch_no = crw0->rsid;
 683         if (crw1)
 684                 mchk_schid.ssid = (crw1->rsid >> 4) & 3;
 685
 686         if (crw0->erc == CRW_ERC_PMOD) {
 687                 sch = get_subchannel_by_schid(mchk_schid);
 688                 if (sch) {
 689                         css_update_ssd_info(sch);
 690                         put_device(&sch->dev);
 691                 }
 692         }
 693         /*
 694          * Since we are always presented with IPI in the CRW, we have to
 695          * use stsch() to find out if the subchannel in question has come
 696          * or gone.
 697          */
 698         css_evaluate_subchannel(mchk_schid, 0);
 699 }
 700
 701 static void __init
 702 css_generate_pgid(struct channel_subsystem *css, u32 tod_high)
 703 {
 704         struct cpuid cpu_id;
 705
 706         if (css_general_characteristics.mcss) {
 707                 css->global_pgid.pgid_high.ext_cssid.version = 0x80;
 708                 css->global_pgid.pgid_high.ext_cssid.cssid = css->cssid;
 709         } else {
 710                 css->global_pgid.pgid_high.cpu_addr = stap();
 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 static void
 719 channel_subsystem_release(struct device *dev)
 720 {
 721         struct channel_subsystem *css;
 722
 723         css = to_css(dev);
 724         mutex_destroy(&css->mutex);
 725         if (css->pseudo_subchannel) {
 726                 /* Implies that it has been generated but never registered. */
 727                 css_subchannel_release(&css->pseudo_subchannel->dev);
 728                 css->pseudo_subchannel = NULL;
 729         }
 730         kfree(css);
 731 }
 732
 733 static ssize_t
 734 css_cm_enable_show(struct device *dev, struct device_attribute *attr,
 735                    char *buf)
 736 {
 737         struct channel_subsystem *css = to_css(dev);
 738         int ret;
 739
 740         if (!css)
 741                 return 0;
 742         mutex_lock(&css->mutex);
 743         ret = sprintf(buf, "%x\n", css->cm_enabled);
 744         mutex_unlock(&css->mutex);
 745         return ret;
 746 }
 747
 748 static ssize_t
 749 css_cm_enable_store(struct device *dev, struct device_attribute *attr,
 750                     const char *buf, size_t count)
 751 {
 752         struct channel_subsystem *css = to_css(dev);
 753         int ret;
 754         unsigned long val;
 755
 756         ret = kstrtoul(buf, 16, &val);
 757         if (ret)
 758                 return ret;
 759         mutex_lock(&css->mutex);
 760         switch (val) {
 761         case 0:
 762                 ret = css->cm_enabled ? chsc_secm(css, 0) : 0;
 763                 break;
 764         case 1:
 765                 ret = css->cm_enabled ? 0 : chsc_secm(css, 1);
 766                 break;
 767         default:
 768                 ret = -EINVAL;
 769         }
 770         mutex_unlock(&css->mutex);
 771         return ret < 0 ? ret : count;
 772 }
 773
 774 static DEVICE_ATTR(cm_enable, 0644, css_cm_enable_show, css_cm_enable_store);
 775
 776 static int __init setup_css(int nr)
 777 {
 778         u32 tod_high;
 779         int ret;
 780         struct channel_subsystem *css;
 781
 782         css = channel_subsystems[nr];
 783         memset(css, 0, sizeof(struct channel_subsystem));
 784         css->pseudo_subchannel =
 785                 kzalloc(sizeof(*css->pseudo_subchannel), GFP_KERNEL);
 786         if (!css->pseudo_subchannel)
 787                 return -ENOMEM;
 788         css->pseudo_subchannel->dev.parent = &css->device;
 789         css->pseudo_subchannel->dev.release = css_subchannel_release;
 790         dev_set_name(&css->pseudo_subchannel->dev, "defunct");
 791         mutex_init(&css->pseudo_subchannel->reg_mutex);
 792         ret = css_sch_create_locks(css->pseudo_subchannel);
 793         if (ret) {
 794                 kfree(css->pseudo_subchannel);
 795                 return ret;
 796         }
 797         mutex_init(&css->mutex);
 798         css->valid = 1;
 799         css->cssid = nr;
 800         dev_set_name(&css->device, "css%x", nr);
 801         css->device.release = channel_subsystem_release;
 802         tod_high = (u32) (get_tod_clock() >> 32);
 803         css_generate_pgid(css, tod_high);
 804         return 0;
 805 }
 806
 807 static int css_reboot_event(struct notifier_block *this,
 808                             unsigned long event,
 809                             void *ptr)
 810 {
 811         int ret, i;
 812
 813         ret = NOTIFY_DONE;
 814         for (i = 0; i <= __MAX_CSSID; i++) {
 815                 struct channel_subsystem *css;
 816
 817                 css = channel_subsystems[i];
 818                 mutex_lock(&css->mutex);
 819                 if (css->cm_enabled)
 820                         if (chsc_secm(css, 0))
 821                                 ret = NOTIFY_BAD;
 822                 mutex_unlock(&css->mutex);
 823         }
 824
 825         return ret;
 826 }
 827
 828 static struct notifier_block css_reboot_notifier = {
 829         .notifier_call = css_reboot_event,
 830 };
 831
 832 /*
 833  * Since the css devices are neither on a bus nor have a class
 834  * nor have a special device type, we cannot stop/restart channel
 835  * path measurements via the normal suspend/resume callbacks, but have
 836  * to use notifiers.
 837  */
 838 static int css_power_event(struct notifier_block *this, unsigned long event,
 839                            void *ptr)
 840 {
 841         int ret, i;
 842
 843         switch (event) {
 844         case PM_HIBERNATION_PREPARE:
 845         case PM_SUSPEND_PREPARE:
 846                 ret = NOTIFY_DONE;
 847                 for (i = 0; i <= __MAX_CSSID; i++) {
 848                         struct channel_subsystem *css;
 849
 850                         css = channel_subsystems[i];
 851                         mutex_lock(&css->mutex);
 852                         if (!css->cm_enabled) {
 853                                 mutex_unlock(&css->mutex);
 854                                 continue;
 855                         }
 856                         ret = __chsc_do_secm(css, 0);
 857                         ret = notifier_from_errno(ret);
 858                         mutex_unlock(&css->mutex);
 859                 }
 860                 break;
 861         case PM_POST_HIBERNATION:
 862         case PM_POST_SUSPEND:
 863                 ret = NOTIFY_DONE;
 864                 for (i = 0; i <= __MAX_CSSID; i++) {
 865                         struct channel_subsystem *css;
 866
 867                         css = channel_subsystems[i];
 868                         mutex_lock(&css->mutex);
 869                         if (!css->cm_enabled) {
 870                                 mutex_unlock(&css->mutex);
 871                                 continue;
 872                         }
 873                         ret = __chsc_do_secm(css, 1);
 874                         ret = notifier_from_errno(ret);
 875                         mutex_unlock(&css->mutex);
 876                 }
 877                 /* search for subchannels, which appeared during hibernation */
 878                 css_schedule_reprobe();
 879                 break;
 880         default:
 881                 ret = NOTIFY_DONE;
 882         }
 883         return ret;
 884
 885 }
 886 static struct notifier_block css_power_notifier = {
 887         .notifier_call = css_power_event,
 888 };
 889
 890 /*
 891  * Now that the driver core is running, we can setup our channel subsystem.
 892  * The struct subchannel's are created during probing.
 893  */
 894 static int __init css_bus_init(void)
 895 {
 896         int ret, i;
 897
 898         ret = chsc_init();
 899         if (ret)
 900                 return ret;
 901
 902         chsc_determine_css_characteristics();
 903         /* Try to enable MSS. */
 904         ret = chsc_enable_facility(CHSC_SDA_OC_MSS);
 905         if (ret)
 906                 max_ssid = 0;
 907         else /* Success. */
 908                 max_ssid = __MAX_SSID;
 909
 910         ret = slow_subchannel_init();
 911         if (ret)
 912                 goto out;
 913
 914         ret = crw_register_handler(CRW_RSC_SCH, css_process_crw);
 915         if (ret)
 916                 goto out;
 917
 918         if ((ret = bus_register(&css_bus_type)))
 919                 goto out;
 920
 921         /* Setup css structure. */
 922         for (i = 0; i <= __MAX_CSSID; i++) {
 923                 struct channel_subsystem *css;
 924
 925                 css = kmalloc(sizeof(struct channel_subsystem), GFP_KERNEL);
 926                 if (!css) {
 927                         ret = -ENOMEM;
 928                         goto out_unregister;
 929                 }
 930                 channel_subsystems[i] = css;
 931                 ret = setup_css(i);
 932                 if (ret) {
 933                         kfree(channel_subsystems[i]);
 934                         goto out_unregister;
 935                 }
 936                 ret = device_register(&css->device);
 937                 if (ret) {
 938                         put_device(&css->device);
 939                         goto out_unregister;
 940                 }
 941                 if (css_chsc_characteristics.secm) {
 942                         ret = device_create_file(&css->device,
 943                                                  &dev_attr_cm_enable);
 944                         if (ret)
 945                                 goto out_device;
 946                 }
 947                 ret = device_register(&css->pseudo_subchannel->dev);
 948                 if (ret) {
 949                         put_device(&css->pseudo_subchannel->dev);
 950                         goto out_file;
 951                 }
 952         }
 953         ret = register_reboot_notifier(&css_reboot_notifier);
 954         if (ret)
 955                 goto out_unregister;
 956         ret = register_pm_notifier(&css_power_notifier);
 957         if (ret) {
 958                 unregister_reboot_notifier(&css_reboot_notifier);
 959                 goto out_unregister;
 960         }
 961         css_init_done = 1;
 962
 963         /* Enable default isc for I/O subchannels. */
 964         isc_register(IO_SCH_ISC);
 965
 966         return 0;
 967 out_file:
 968         if (css_chsc_characteristics.secm)
 969                 device_remove_file(&channel_subsystems[i]->device,
 970                                    &dev_attr_cm_enable);
 971 out_device:
 972         device_unregister(&channel_subsystems[i]->device);
 973 out_unregister:
 974         while (i > 0) {
 975                 struct channel_subsystem *css;
 976
 977                 i--;
 978                 css = channel_subsystems[i];
 979                 device_unregister(&css->pseudo_subchannel->dev);
 980                 css->pseudo_subchannel = NULL;
 981                 if (css_chsc_characteristics.secm)
 982                         device_remove_file(&css->device,
 983                                            &dev_attr_cm_enable);
 984                 device_unregister(&css->device);
 985         }
 986         bus_unregister(&css_bus_type);
 987 out:
 988         crw_unregister_handler(CRW_RSC_SCH);
 989         idset_free(slow_subchannel_set);
 990         chsc_init_cleanup();
 991         pr_alert("The CSS device driver initialization failed with "
 992                  "errno=%d\n", ret);
 993         return ret;
 994 }
 995
 996 static void __init css_bus_cleanup(void)
 997 {
 998         struct channel_subsystem *css;
 999         int i;
1000
1001         for (i = 0; i <= __MAX_CSSID; i++) {
1002                 css = channel_subsystems[i];
1003                 device_unregister(&css->pseudo_subchannel->dev);
1004                 css->pseudo_subchannel = NULL;
1005                 if (css_chsc_characteristics.secm)
1006                         device_remove_file(&css->device, &dev_attr_cm_enable);
1007                 device_unregister(&css->device);
1008         }
1009         bus_unregister(&css_bus_type);
1010         crw_unregister_handler(CRW_RSC_SCH);
1011         idset_free(slow_subchannel_set);
1012         chsc_init_cleanup();
1013         isc_unregister(IO_SCH_ISC);
1014 }
1015
1016 static int __init channel_subsystem_init(void)
1017 {
1018         int ret;
1019
1020         ret = css_bus_init();
1021         if (ret)
1022                 return ret;
1023         cio_work_q = create_singlethread_workqueue("cio");
1024         if (!cio_work_q) {
1025                 ret = -ENOMEM;
1026                 goto out_bus;
1027         }
1028         ret = io_subchannel_init();
1029         if (ret)
1030                 goto out_wq;
1031
1032         return ret;
1033 out_wq:
1034         destroy_workqueue(cio_work_q);
1035 out_bus:
1036         css_bus_cleanup();
1037         return ret;
1038 }
1039 subsys_initcall(channel_subsystem_init);
1040
1041 static int css_settle(struct device_driver *drv, void *unused)
1042 {
1043         struct css_driver *cssdrv = to_cssdriver(drv);
1044
1045         if (cssdrv->settle)
1046                 return cssdrv->settle();
1047         return 0;
1048 }
1049
1050 int css_complete_work(void)
1051 {
1052         int ret;
1053
1054         /* Wait for the evaluation of subchannels to finish. */
1055         ret = wait_event_interruptible(css_eval_wq,
1056                                        atomic_read(&css_eval_scheduled) == 0);
1057         if (ret)
1058                 return -EINTR;
1059         flush_workqueue(cio_work_q);
1060         /* Wait for the subchannel type specific initialization to finish */
1061         return bus_for_each_drv(&css_bus_type, NULL, NULL, css_settle);
1062 }
1063
1064
1065 /*
1066  * Wait for the initialization of devices to finish, to make sure we are
1067  * done with our setup if the search for the root device starts.
1068  */
1069 static int __init channel_subsystem_init_sync(void)
1070 {
1071         /* Register subchannels which are already in use. */
1072         cio_register_early_subchannels();
1073         /* Start initial subchannel evaluation. */
1074         css_schedule_eval_all();
1075         css_complete_work();
1076         return 0;
1077 }
1078 subsys_initcall_sync(channel_subsystem_init_sync);
1079
1080 void channel_subsystem_reinit(void)
1081 {
1082         struct channel_path *chp;
1083         struct chp_id chpid;
1084
1085         chsc_enable_facility(CHSC_SDA_OC_MSS);
1086         chp_id_for_each(&chpid) {
1087                 chp = chpid_to_chp(chpid);
1088                 if (chp)
1089                         chp_update_desc(chp);
1090         }
1091         cmf_reactivate();
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         if (!sch->dev.parent)
1129                 return 0;
1130         return sch == to_css(sch->dev.parent)->pseudo_subchannel;
1131 }
1132
1133 static int css_bus_match(struct device *dev, struct device_driver *drv)
1134 {
1135         struct subchannel *sch = to_subchannel(dev);
1136         struct css_driver *driver = to_cssdriver(drv);
1137         struct css_device_id *id;
1138
1139         for (id = driver->subchannel_type; id->match_flags; id++) {
1140                 if (sch->st == id->type)
1141                         return 1;
1142         }
1143
1144         return 0;
1145 }
1146
1147 static int css_probe(struct device *dev)
1148 {
1149         struct subchannel *sch;
1150         int ret;
1151
1152         sch = to_subchannel(dev);
1153         sch->driver = to_cssdriver(dev->driver);
1154         ret = sch->driver->probe ? sch->driver->probe(sch) : 0;
1155         if (ret)
1156                 sch->driver = NULL;
1157         return ret;
1158 }
1159
1160 static int css_remove(struct device *dev)
1161 {
1162         struct subchannel *sch;
1163         int ret;
1164
1165         sch = to_subchannel(dev);
1166         ret = sch->driver->remove ? sch->driver->remove(sch) : 0;
1167         sch->driver = NULL;
1168         return ret;
1169 }
1170
1171 static void css_shutdown(struct device *dev)
1172 {
1173         struct subchannel *sch;
1174
1175         sch = to_subchannel(dev);
1176         if (sch->driver && sch->driver->shutdown)
1177                 sch->driver->shutdown(sch);
1178 }
1179
1180 static int css_uevent(struct device *dev, struct kobj_uevent_env *env)
1181 {
1182         struct subchannel *sch = to_subchannel(dev);
1183         int ret;
1184
1185         ret = add_uevent_var(env, "ST=%01X", sch->st);
1186         if (ret)
1187                 return ret;
1188         ret = add_uevent_var(env, "MODALIAS=css:t%01X", sch->st);
1189         return ret;
1190 }
1191
1192 static int css_pm_prepare(struct device *dev)
1193 {
1194         struct subchannel *sch = to_subchannel(dev);
1195         struct css_driver *drv;
1196
1197         if (mutex_is_locked(&sch->reg_mutex))
1198                 return -EAGAIN;
1199         if (!sch->dev.driver)
1200                 return 0;
1201         drv = to_cssdriver(sch->dev.driver);
1202         /* Notify drivers that they may not register children. */
1203         return drv->prepare ? drv->prepare(sch) : 0;
1204 }
1205
1206 static void css_pm_complete(struct device *dev)
1207 {
1208         struct subchannel *sch = to_subchannel(dev);
1209         struct css_driver *drv;
1210
1211         if (!sch->dev.driver)
1212                 return;
1213         drv = to_cssdriver(sch->dev.driver);
1214         if (drv->complete)
1215                 drv->complete(sch);
1216 }
1217
1218 static int css_pm_freeze(struct device *dev)
1219 {
1220         struct subchannel *sch = to_subchannel(dev);
1221         struct css_driver *drv;
1222
1223         if (!sch->dev.driver)
1224                 return 0;
1225         drv = to_cssdriver(sch->dev.driver);
1226         return drv->freeze ? drv->freeze(sch) : 0;
1227 }
1228
1229 static int css_pm_thaw(struct device *dev)
1230 {
1231         struct subchannel *sch = to_subchannel(dev);
1232         struct css_driver *drv;
1233
1234         if (!sch->dev.driver)
1235                 return 0;
1236         drv = to_cssdriver(sch->dev.driver);
1237         return drv->thaw ? drv->thaw(sch) : 0;
1238 }
1239
1240 static int css_pm_restore(struct device *dev)
1241 {
1242         struct subchannel *sch = to_subchannel(dev);
1243         struct css_driver *drv;
1244
1245         css_update_ssd_info(sch);
1246         if (!sch->dev.driver)
1247                 return 0;
1248         drv = to_cssdriver(sch->dev.driver);
1249         return drv->restore ? drv->restore(sch) : 0;
1250 }
1251
1252 static const struct dev_pm_ops css_pm_ops = {
1253         .prepare = css_pm_prepare,
1254         .complete = css_pm_complete,
1255         .freeze = css_pm_freeze,
1256         .thaw = css_pm_thaw,
1257         .restore = css_pm_restore,
1258 };
1259
1260 static struct bus_type css_bus_type = {
1261         .name     = "css",
1262         .match    = css_bus_match,
1263         .probe    = css_probe,
1264         .remove   = css_remove,
1265         .shutdown = css_shutdown,
1266         .uevent   = css_uevent,
1267         .pm = &css_pm_ops,
1268 };
1269
1270 /**
1271  * css_driver_register - register a css driver
1272  * @cdrv: css driver to register
1273  *
1274  * This is mainly a wrapper around driver_register that sets name
1275  * and bus_type in the embedded struct device_driver correctly.
1276  */
1277 int css_driver_register(struct css_driver *cdrv)
1278 {
1279         cdrv->drv.bus = &css_bus_type;
1280         return driver_register(&cdrv->drv);
1281 }
1282 EXPORT_SYMBOL_GPL(css_driver_register);
1283
1284 /**
1285  * css_driver_unregister - unregister a css driver
1286  * @cdrv: css driver to unregister
1287  *
1288  * This is a wrapper around driver_unregister.
1289  */
1290 void css_driver_unregister(struct css_driver *cdrv)
1291 {
1292         driver_unregister(&cdrv->drv);
1293 }
1294 EXPORT_SYMBOL_GPL(css_driver_unregister);
1295
1296 MODULE_LICENSE("GPL");