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         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         return 0;
 534 }
 535
 536 static int slow_eval_unknown_fn(struct subchannel_id schid, void *data)
 537 {
 538         int eval;
 539         int rc = 0;
 540
 541         spin_lock_irq(&slow_subchannel_lock);
 542         eval = idset_sch_contains(slow_subchannel_set, schid);
 543         idset_sch_del(slow_subchannel_set, schid);
 544         spin_unlock_irq(&slow_subchannel_lock);
 545         if (eval) {
 546                 rc = css_evaluate_new_subchannel(schid, 1);
 547                 switch (rc) {
 548                 case -EAGAIN:
 549                         css_schedule_eval(schid);
 550                         rc = 0;
 551                         break;
 552                 case -ENXIO:
 553                 case -ENOMEM:
 554                 case -EIO:
 555                         /* These should abort looping */
 556                         spin_lock_irq(&slow_subchannel_lock);
 557                         idset_sch_del_subseq(slow_subchannel_set, schid);
 558                         spin_unlock_irq(&slow_subchannel_lock);
 559                         break;
 560                 default:
 561                         rc = 0;
 562                 }
 563                 /* Allow scheduling here since the containing loop might
 564                  * take a while.  */
 565                 cond_resched();
 566         }
 567         return rc;
 568 }
 569
 570 static void css_slow_path_func(struct work_struct *unused)
 571 {
 572         unsigned long flags;
 573
 574         CIO_TRACE_EVENT(4, "slowpath");
 575         for_each_subchannel_staged(slow_eval_known_fn, slow_eval_unknown_fn,
 576                                    NULL);
 577         spin_lock_irqsave(&slow_subchannel_lock, flags);
 578         if (idset_is_empty(slow_subchannel_set)) {
 579                 atomic_set(&css_eval_scheduled, 0);
 580                 wake_up(&css_eval_wq);
 581         }
 582         spin_unlock_irqrestore(&slow_subchannel_lock, flags);
 583 }
 584
 585 static DECLARE_DELAYED_WORK(slow_path_work, css_slow_path_func);
 586 struct workqueue_struct *cio_work_q;
 587
 588 void css_schedule_eval(struct subchannel_id schid)
 589 {
 590         unsigned long flags;
 591
 592         spin_lock_irqsave(&slow_subchannel_lock, flags);
 593         idset_sch_add(slow_subchannel_set, schid);
 594         atomic_set(&css_eval_scheduled, 1);
 595         queue_delayed_work(cio_work_q, &slow_path_work, 0);
 596         spin_unlock_irqrestore(&slow_subchannel_lock, flags);
 597 }
 598
 599 void css_schedule_eval_all(void)
 600 {
 601         unsigned long flags;
 602
 603         spin_lock_irqsave(&slow_subchannel_lock, flags);
 604         idset_fill(slow_subchannel_set);
 605         atomic_set(&css_eval_scheduled, 1);
 606         queue_delayed_work(cio_work_q, &slow_path_work, 0);
 607         spin_unlock_irqrestore(&slow_subchannel_lock, flags);
 608 }
 609
 610 static int __unset_registered(struct device *dev, void *data)
 611 {
 612         struct idset *set = data;
 613         struct subchannel *sch = to_subchannel(dev);
 614
 615         idset_sch_del(set, sch->schid);
 616         return 0;
 617 }
 618
 619 void css_schedule_eval_all_unreg(unsigned long delay)
 620 {
 621         unsigned long flags;
 622         struct idset *unreg_set;
 623
 624         /* Find unregistered subchannels. */
 625         unreg_set = idset_sch_new();
 626         if (!unreg_set) {
 627                 /* Fallback. */
 628                 css_schedule_eval_all();
 629                 return;
 630         }
 631         idset_fill(unreg_set);
 632         bus_for_each_dev(&css_bus_type, NULL, unreg_set, __unset_registered);
 633         /* Apply to slow_subchannel_set. */
 634         spin_lock_irqsave(&slow_subchannel_lock, flags);
 635         idset_add_set(slow_subchannel_set, unreg_set);
 636         atomic_set(&css_eval_scheduled, 1);
 637         queue_delayed_work(cio_work_q, &slow_path_work, delay);
 638         spin_unlock_irqrestore(&slow_subchannel_lock, flags);
 639         idset_free(unreg_set);
 640 }
 641
 642 void css_wait_for_slow_path(void)
 643 {
 644         flush_workqueue(cio_work_q);
 645 }
 646
 647 /* Schedule reprobing of all unregistered subchannels. */
 648 void css_schedule_reprobe(void)
 649 {
 650         /* Schedule with a delay to allow merging of subsequent calls. */
 651         css_schedule_eval_all_unreg(1 * HZ);
 652 }
 653 EXPORT_SYMBOL_GPL(css_schedule_reprobe);
 654
 655 /*
 656  * Called from the machine check handler for subchannel report words.
 657  */
 658 static void css_process_crw(struct crw *crw0, struct crw *crw1, int overflow)
 659 {
 660         struct subchannel_id mchk_schid;
 661         struct subchannel *sch;
 662
 663         if (overflow) {
 664                 css_schedule_eval_all();
 665                 return;
 666         }
 667         CIO_CRW_EVENT(2, "CRW0 reports slct=%d, oflw=%d, "
 668                       "chn=%d, rsc=%X, anc=%d, erc=%X, rsid=%X\n",
 669                       crw0->slct, crw0->oflw, crw0->chn, crw0->rsc, crw0->anc,
 670                       crw0->erc, crw0->rsid);
 671         if (crw1)
 672                 CIO_CRW_EVENT(2, "CRW1 reports slct=%d, oflw=%d, "
 673                               "chn=%d, rsc=%X, anc=%d, erc=%X, rsid=%X\n",
 674                               crw1->slct, crw1->oflw, crw1->chn, crw1->rsc,
 675                               crw1->anc, crw1->erc, crw1->rsid);
 676         init_subchannel_id(&mchk_schid);
 677         mchk_schid.sch_no = crw0->rsid;
 678         if (crw1)
 679                 mchk_schid.ssid = (crw1->rsid >> 4) & 3;
 680
 681         if (crw0->erc == CRW_ERC_PMOD) {
 682                 sch = get_subchannel_by_schid(mchk_schid);
 683                 if (sch) {
 684                         css_update_ssd_info(sch);
 685                         put_device(&sch->dev);
 686                 }
 687         }
 688         /*
 689          * Since we are always presented with IPI in the CRW, we have to
 690          * use stsch() to find out if the subchannel in question has come
 691          * or gone.
 692          */
 693         css_evaluate_subchannel(mchk_schid, 0);
 694 }
 695
 696 static void __init
 697 css_generate_pgid(struct channel_subsystem *css, u32 tod_high)
 698 {
 699         struct cpuid cpu_id;
 700
 701         if (css_general_characteristics.mcss) {
 702                 css->global_pgid.pgid_high.ext_cssid.version = 0x80;
 703                 css->global_pgid.pgid_high.ext_cssid.cssid = css->cssid;
 704         } else {
 705                 css->global_pgid.pgid_high.cpu_addr = stap();
 706         }
 707         get_cpu_id(&cpu_id);
 708         css->global_pgid.cpu_id = cpu_id.ident;
 709         css->global_pgid.cpu_model = cpu_id.machine;
 710         css->global_pgid.tod_high = tod_high;
 711 }
 712
 713 static void
 714 channel_subsystem_release(struct device *dev)
 715 {
 716         struct channel_subsystem *css;
 717
 718         css = to_css(dev);
 719         mutex_destroy(&css->mutex);
 720         if (css->pseudo_subchannel) {
 721                 /* Implies that it has been generated but never registered. */
 722                 css_subchannel_release(&css->pseudo_subchannel->dev);
 723                 css->pseudo_subchannel = NULL;
 724         }
 725         kfree(css);
 726 }
 727
 728 static ssize_t
 729 css_cm_enable_show(struct device *dev, struct device_attribute *attr,
 730                    char *buf)
 731 {
 732         struct channel_subsystem *css = to_css(dev);
 733         int ret;
 734
 735         if (!css)
 736                 return 0;
 737         mutex_lock(&css->mutex);
 738         ret = sprintf(buf, "%x\n", css->cm_enabled);
 739         mutex_unlock(&css->mutex);
 740         return ret;
 741 }
 742
 743 static ssize_t
 744 css_cm_enable_store(struct device *dev, struct device_attribute *attr,
 745                     const char *buf, size_t count)
 746 {
 747         struct channel_subsystem *css = to_css(dev);
 748         int ret;
 749         unsigned long val;
 750
 751         ret = kstrtoul(buf, 16, &val);
 752         if (ret)
 753                 return ret;
 754         mutex_lock(&css->mutex);
 755         switch (val) {
 756         case 0:
 757                 ret = css->cm_enabled ? chsc_secm(css, 0) : 0;
 758                 break;
 759         case 1:
 760                 ret = css->cm_enabled ? 0 : chsc_secm(css, 1);
 761                 break;
 762         default:
 763                 ret = -EINVAL;
 764         }
 765         mutex_unlock(&css->mutex);
 766         return ret < 0 ? ret : count;
 767 }
 768
 769 static DEVICE_ATTR(cm_enable, 0644, css_cm_enable_show, css_cm_enable_store);
 770
 771 static int __init setup_css(int nr)
 772 {
 773         u32 tod_high;
 774         int ret;
 775         struct channel_subsystem *css;
 776
 777         css = channel_subsystems[nr];
 778         memset(css, 0, sizeof(struct channel_subsystem));
 779         css->pseudo_subchannel =
 780                 kzalloc(sizeof(*css->pseudo_subchannel), GFP_KERNEL);
 781         if (!css->pseudo_subchannel)
 782                 return -ENOMEM;
 783         css->pseudo_subchannel->dev.parent = &css->device;
 784         css->pseudo_subchannel->dev.release = css_subchannel_release;
 785         dev_set_name(&css->pseudo_subchannel->dev, "defunct");
 786         mutex_init(&css->pseudo_subchannel->reg_mutex);
 787         ret = css_sch_create_locks(css->pseudo_subchannel);
 788         if (ret) {
 789                 kfree(css->pseudo_subchannel);
 790                 return ret;
 791         }
 792         mutex_init(&css->mutex);
 793         css->valid = 1;
 794         css->cssid = nr;
 795         dev_set_name(&css->device, "css%x", nr);
 796         css->device.release = channel_subsystem_release;
 797         tod_high = (u32) (get_tod_clock() >> 32);
 798         css_generate_pgid(css, tod_high);
 799         return 0;
 800 }
 801
 802 static int css_reboot_event(struct notifier_block *this,
 803                             unsigned long event,
 804                             void *ptr)
 805 {
 806         int ret, i;
 807
 808         ret = NOTIFY_DONE;
 809         for (i = 0; i <= __MAX_CSSID; i++) {
 810                 struct channel_subsystem *css;
 811
 812                 css = channel_subsystems[i];
 813                 mutex_lock(&css->mutex);
 814                 if (css->cm_enabled)
 815                         if (chsc_secm(css, 0))
 816                                 ret = NOTIFY_BAD;
 817                 mutex_unlock(&css->mutex);
 818         }
 819
 820         return ret;
 821 }
 822
 823 static struct notifier_block css_reboot_notifier = {
 824         .notifier_call = css_reboot_event,
 825 };
 826
 827 /*
 828  * Since the css devices are neither on a bus nor have a class
 829  * nor have a special device type, we cannot stop/restart channel
 830  * path measurements via the normal suspend/resume callbacks, but have
 831  * to use notifiers.
 832  */
 833 static int css_power_event(struct notifier_block *this, unsigned long event,
 834                            void *ptr)
 835 {
 836         int ret, i;
 837
 838         switch (event) {
 839         case PM_HIBERNATION_PREPARE:
 840         case PM_SUSPEND_PREPARE:
 841                 ret = NOTIFY_DONE;
 842                 for (i = 0; i <= __MAX_CSSID; i++) {
 843                         struct channel_subsystem *css;
 844
 845                         css = channel_subsystems[i];
 846                         mutex_lock(&css->mutex);
 847                         if (!css->cm_enabled) {
 848                                 mutex_unlock(&css->mutex);
 849                                 continue;
 850                         }
 851                         ret = __chsc_do_secm(css, 0);
 852                         ret = notifier_from_errno(ret);
 853                         mutex_unlock(&css->mutex);
 854                 }
 855                 break;
 856         case PM_POST_HIBERNATION:
 857         case PM_POST_SUSPEND:
 858                 ret = NOTIFY_DONE;
 859                 for (i = 0; i <= __MAX_CSSID; i++) {
 860                         struct channel_subsystem *css;
 861
 862                         css = channel_subsystems[i];
 863                         mutex_lock(&css->mutex);
 864                         if (!css->cm_enabled) {
 865                                 mutex_unlock(&css->mutex);
 866                                 continue;
 867                         }
 868                         ret = __chsc_do_secm(css, 1);
 869                         ret = notifier_from_errno(ret);
 870                         mutex_unlock(&css->mutex);
 871                 }
 872                 /* search for subchannels, which appeared during hibernation */
 873                 css_schedule_reprobe();
 874                 break;
 875         default:
 876                 ret = NOTIFY_DONE;
 877         }
 878         return ret;
 879
 880 }
 881 static struct notifier_block css_power_notifier = {
 882         .notifier_call = css_power_event,
 883 };
 884
 885 /*
 886  * Now that the driver core is running, we can setup our channel subsystem.
 887  * The struct subchannel's are created during probing.
 888  */
 889 static int __init css_bus_init(void)
 890 {
 891         int ret, i;
 892
 893         ret = chsc_init();
 894         if (ret)
 895                 return ret;
 896
 897         chsc_determine_css_characteristics();
 898         /* Try to enable MSS. */
 899         ret = chsc_enable_facility(CHSC_SDA_OC_MSS);
 900         if (ret)
 901                 max_ssid = 0;
 902         else /* Success. */
 903                 max_ssid = __MAX_SSID;
 904
 905         ret = slow_subchannel_init();
 906         if (ret)
 907                 goto out;
 908
 909         ret = crw_register_handler(CRW_RSC_SCH, css_process_crw);
 910         if (ret)
 911                 goto out;
 912
 913         if ((ret = bus_register(&css_bus_type)))
 914                 goto out;
 915
 916         /* Setup css structure. */
 917         for (i = 0; i <= __MAX_CSSID; i++) {
 918                 struct channel_subsystem *css;
 919
 920                 css = kmalloc(sizeof(struct channel_subsystem), GFP_KERNEL);
 921                 if (!css) {
 922                         ret = -ENOMEM;
 923                         goto out_unregister;
 924                 }
 925                 channel_subsystems[i] = css;
 926                 ret = setup_css(i);
 927                 if (ret) {
 928                         kfree(channel_subsystems[i]);
 929                         goto out_unregister;
 930                 }
 931                 ret = device_register(&css->device);
 932                 if (ret) {
 933                         put_device(&css->device);
 934                         goto out_unregister;
 935                 }
 936                 if (css_chsc_characteristics.secm) {
 937                         ret = device_create_file(&css->device,
 938                                                  &dev_attr_cm_enable);
 939                         if (ret)
 940                                 goto out_device;
 941                 }
 942                 ret = device_register(&css->pseudo_subchannel->dev);
 943                 if (ret) {
 944                         put_device(&css->pseudo_subchannel->dev);
 945                         goto out_file;
 946                 }
 947         }
 948         ret = register_reboot_notifier(&css_reboot_notifier);
 949         if (ret)
 950                 goto out_unregister;
 951         ret = register_pm_notifier(&css_power_notifier);
 952         if (ret) {
 953                 unregister_reboot_notifier(&css_reboot_notifier);
 954                 goto out_unregister;
 955         }
 956         css_init_done = 1;
 957
 958         /* Enable default isc for I/O subchannels. */
 959         isc_register(IO_SCH_ISC);
 960
 961         return 0;
 962 out_file:
 963         if (css_chsc_characteristics.secm)
 964                 device_remove_file(&channel_subsystems[i]->device,
 965                                    &dev_attr_cm_enable);
 966 out_device:
 967         device_unregister(&channel_subsystems[i]->device);
 968 out_unregister:
 969         while (i > 0) {
 970                 struct channel_subsystem *css;
 971
 972                 i--;
 973                 css = channel_subsystems[i];
 974                 device_unregister(&css->pseudo_subchannel->dev);
 975                 css->pseudo_subchannel = NULL;
 976                 if (css_chsc_characteristics.secm)
 977                         device_remove_file(&css->device,
 978                                            &dev_attr_cm_enable);
 979                 device_unregister(&css->device);
 980         }
 981         bus_unregister(&css_bus_type);
 982 out:
 983         crw_unregister_handler(CRW_RSC_SCH);
 984         idset_free(slow_subchannel_set);
 985         chsc_init_cleanup();
 986         pr_alert("The CSS device driver initialization failed with "
 987                  "errno=%d\n", ret);
 988         return ret;
 989 }
 990
 991 static void __init css_bus_cleanup(void)
 992 {
 993         struct channel_subsystem *css;
 994         int i;
 995
 996         for (i = 0; i <= __MAX_CSSID; i++) {
 997                 css = channel_subsystems[i];
 998                 device_unregister(&css->pseudo_subchannel->dev);
 999                 css->pseudo_subchannel = NULL;
1000                 if (css_chsc_characteristics.secm)
1001                         device_remove_file(&css->device, &dev_attr_cm_enable);
1002                 device_unregister(&css->device);
1003         }
1004         bus_unregister(&css_bus_type);
1005         crw_unregister_handler(CRW_RSC_SCH);
1006         idset_free(slow_subchannel_set);
1007         chsc_init_cleanup();
1008         isc_unregister(IO_SCH_ISC);
1009 }
1010
1011 static int __init channel_subsystem_init(void)
1012 {
1013         int ret;
1014
1015         ret = css_bus_init();
1016         if (ret)
1017                 return ret;
1018         cio_work_q = create_singlethread_workqueue("cio");
1019         if (!cio_work_q) {
1020                 ret = -ENOMEM;
1021                 goto out_bus;
1022         }
1023         ret = io_subchannel_init();
1024         if (ret)
1025                 goto out_wq;
1026
1027         return ret;
1028 out_wq:
1029         destroy_workqueue(cio_work_q);
1030 out_bus:
1031         css_bus_cleanup();
1032         return ret;
1033 }
1034 subsys_initcall(channel_subsystem_init);
1035
1036 static int css_settle(struct device_driver *drv, void *unused)
1037 {
1038         struct css_driver *cssdrv = to_cssdriver(drv);
1039
1040         if (cssdrv->settle)
1041                 return cssdrv->settle();
1042         return 0;
1043 }
1044
1045 int css_complete_work(void)
1046 {
1047         int ret;
1048
1049         /* Wait for the evaluation of subchannels to finish. */
1050         ret = wait_event_interruptible(css_eval_wq,
1051                                        atomic_read(&css_eval_scheduled) == 0);
1052         if (ret)
1053                 return -EINTR;
1054         flush_workqueue(cio_work_q);
1055         /* Wait for the subchannel type specific initialization to finish */
1056         return bus_for_each_drv(&css_bus_type, NULL, NULL, css_settle);
1057 }
1058
1059
1060 /*
1061  * Wait for the initialization of devices to finish, to make sure we are
1062  * done with our setup if the search for the root device starts.
1063  */
1064 static int __init channel_subsystem_init_sync(void)
1065 {
1066         /* Register subchannels which are already in use. */
1067         cio_register_early_subchannels();
1068         /* Start initial subchannel evaluation. */
1069         css_schedule_eval_all();
1070         css_complete_work();
1071         return 0;
1072 }
1073 subsys_initcall_sync(channel_subsystem_init_sync);
1074
1075 void channel_subsystem_reinit(void)
1076 {
1077         struct channel_path *chp;
1078         struct chp_id chpid;
1079
1080         chsc_enable_facility(CHSC_SDA_OC_MSS);
1081         chp_id_for_each(&chpid) {
1082                 chp = chpid_to_chp(chpid);
1083                 if (chp)
1084                         chp_update_desc(chp);
1085         }
1086         cmf_reactivate();
1087 }
1088
1089 #ifdef CONFIG_PROC_FS
1090 static ssize_t cio_settle_write(struct file *file, const char __user *buf,
1091                                 size_t count, loff_t *ppos)
1092 {
1093         int ret;
1094
1095         /* Handle pending CRW's. */
1096         crw_wait_for_channel_report();
1097         ret = css_complete_work();
1098
1099         return ret ? ret : count;
1100 }
1101
1102 static const struct file_operations cio_settle_proc_fops = {
1103         .open = nonseekable_open,
1104         .write = cio_settle_write,
1105         .llseek = no_llseek,
1106 };
1107
1108 static int __init cio_settle_init(void)
1109 {
1110         struct proc_dir_entry *entry;
1111
1112         entry = proc_create("cio_settle", S_IWUSR, NULL,
1113                             &cio_settle_proc_fops);
1114         if (!entry)
1115                 return -ENOMEM;
1116         return 0;
1117 }
1118 device_initcall(cio_settle_init);
1119 #endif /*CONFIG_PROC_FS*/
1120
1121 int sch_is_pseudo_sch(struct subchannel *sch)
1122 {
1123         return sch == to_css(sch->dev.parent)->pseudo_subchannel;
1124 }
1125
1126 static int css_bus_match(struct device *dev, struct device_driver *drv)
1127 {
1128         struct subchannel *sch = to_subchannel(dev);
1129         struct css_driver *driver = to_cssdriver(drv);
1130         struct css_device_id *id;
1131
1132         for (id = driver->subchannel_type; id->match_flags; id++) {
1133                 if (sch->st == id->type)
1134                         return 1;
1135         }
1136
1137         return 0;
1138 }
1139
1140 static int css_probe(struct device *dev)
1141 {
1142         struct subchannel *sch;
1143         int ret;
1144
1145         sch = to_subchannel(dev);
1146         sch->driver = to_cssdriver(dev->driver);
1147         ret = sch->driver->probe ? sch->driver->probe(sch) : 0;
1148         if (ret)
1149                 sch->driver = NULL;
1150         return ret;
1151 }
1152
1153 static int css_remove(struct device *dev)
1154 {
1155         struct subchannel *sch;
1156         int ret;
1157
1158         sch = to_subchannel(dev);
1159         ret = sch->driver->remove ? sch->driver->remove(sch) : 0;
1160         sch->driver = NULL;
1161         return ret;
1162 }
1163
1164 static void css_shutdown(struct device *dev)
1165 {
1166         struct subchannel *sch;
1167
1168         sch = to_subchannel(dev);
1169         if (sch->driver && sch->driver->shutdown)
1170                 sch->driver->shutdown(sch);
1171 }
1172
1173 static int css_uevent(struct device *dev, struct kobj_uevent_env *env)
1174 {
1175         struct subchannel *sch = to_subchannel(dev);
1176         int ret;
1177
1178         ret = add_uevent_var(env, "ST=%01X", sch->st);
1179         if (ret)
1180                 return ret;
1181         ret = add_uevent_var(env, "MODALIAS=css:t%01X", sch->st);
1182         return ret;
1183 }
1184
1185 static int css_pm_prepare(struct device *dev)
1186 {
1187         struct subchannel *sch = to_subchannel(dev);
1188         struct css_driver *drv;
1189
1190         if (mutex_is_locked(&sch->reg_mutex))
1191                 return -EAGAIN;
1192         if (!sch->dev.driver)
1193                 return 0;
1194         drv = to_cssdriver(sch->dev.driver);
1195         /* Notify drivers that they may not register children. */
1196         return drv->prepare ? drv->prepare(sch) : 0;
1197 }
1198
1199 static void css_pm_complete(struct device *dev)
1200 {
1201         struct subchannel *sch = to_subchannel(dev);
1202         struct css_driver *drv;
1203
1204         if (!sch->dev.driver)
1205                 return;
1206         drv = to_cssdriver(sch->dev.driver);
1207         if (drv->complete)
1208                 drv->complete(sch);
1209 }
1210
1211 static int css_pm_freeze(struct device *dev)
1212 {
1213         struct subchannel *sch = to_subchannel(dev);
1214         struct css_driver *drv;
1215
1216         if (!sch->dev.driver)
1217                 return 0;
1218         drv = to_cssdriver(sch->dev.driver);
1219         return drv->freeze ? drv->freeze(sch) : 0;
1220 }
1221
1222 static int css_pm_thaw(struct device *dev)
1223 {
1224         struct subchannel *sch = to_subchannel(dev);
1225         struct css_driver *drv;
1226
1227         if (!sch->dev.driver)
1228                 return 0;
1229         drv = to_cssdriver(sch->dev.driver);
1230         return drv->thaw ? drv->thaw(sch) : 0;
1231 }
1232
1233 static int css_pm_restore(struct device *dev)
1234 {
1235         struct subchannel *sch = to_subchannel(dev);
1236         struct css_driver *drv;
1237
1238         css_update_ssd_info(sch);
1239         if (!sch->dev.driver)
1240                 return 0;
1241         drv = to_cssdriver(sch->dev.driver);
1242         return drv->restore ? drv->restore(sch) : 0;
1243 }
1244
1245 static const struct dev_pm_ops css_pm_ops = {
1246         .prepare = css_pm_prepare,
1247         .complete = css_pm_complete,
1248         .freeze = css_pm_freeze,
1249         .thaw = css_pm_thaw,
1250         .restore = css_pm_restore,
1251 };
1252
1253 static struct bus_type css_bus_type = {
1254         .name     = "css",
1255         .match    = css_bus_match,
1256         .probe    = css_probe,
1257         .remove   = css_remove,
1258         .shutdown = css_shutdown,
1259         .uevent   = css_uevent,
1260         .pm = &css_pm_ops,
1261 };
1262
1263 /**
1264  * css_driver_register - register a css driver
1265  * @cdrv: css driver to register
1266  *
1267  * This is mainly a wrapper around driver_register that sets name
1268  * and bus_type in the embedded struct device_driver correctly.
1269  */
1270 int css_driver_register(struct css_driver *cdrv)
1271 {
1272         cdrv->drv.bus = &css_bus_type;
1273         return driver_register(&cdrv->drv);
1274 }
1275 EXPORT_SYMBOL_GPL(css_driver_register);
1276
1277 /**
1278  * css_driver_unregister - unregister a css driver
1279  * @cdrv: css driver to unregister
1280  *
1281  * This is a wrapper around driver_unregister.
1282  */
1283 void css_driver_unregister(struct css_driver *cdrv)
1284 {
1285         driver_unregister(&cdrv->drv);
1286 }
1287 EXPORT_SYMBOL_GPL(css_driver_unregister);
1288
1289 MODULE_LICENSE("GPL");