drivers/s390/cio/css.c

   1 /*
   2  * driver for channel subsystem
   3  *
   4  * Copyright IBM Corp. 2002, 2010
   5  *
   6  * Author(s): Arnd Bergmann (arndb@de.ibm.com)
   7  *            Cornelia Huck (cornelia.huck@de.ibm.com)
   8  *
   9  * License: GPL
  10  */
  11
  12 #define KMSG_COMPONENT "cio"
  13 #define pr_fmt(fmt) KMSG_COMPONENT ": " fmt
  14
  15 #include <linux/export.h>
  16 #include <linux/init.h>
  17 #include <linux/device.h>
  18 #include <linux/slab.h>
  19 #include <linux/errno.h>
  20 #include <linux/list.h>
  21 #include <linux/reboot.h>
  22 #include <linux/suspend.h>
  23 #include <linux/proc_fs.h>
  24 #include <asm/isc.h>
  25 #include <asm/crw.h>
  26
  27 #include "css.h"
  28 #include "cio.h"
  29 #include "cio_debug.h"
  30 #include "ioasm.h"
  31 #include "chsc.h"
  32 #include "device.h"
  33 #include "idset.h"
  34 #include "chp.h"
  35
  36 int css_init_done = 0;
  37 int max_ssid;
  38
  39 #define MAX_CSS_IDX 0
  40 struct channel_subsystem *channel_subsystems[MAX_CSS_IDX + 1];
  41 static struct bus_type css_bus_type;
  42
  43 int
  44 for_each_subchannel(int(*fn)(struct subchannel_id, void *), void *data)
  45 {
  46         struct subchannel_id schid;
  47         int ret;
  48
  49         init_subchannel_id(&schid);
  50         do {
  51                 do {
  52                         ret = fn(schid, data);
  53                         if (ret)
  54                                 break;
  55                 } while (schid.sch_no++ < __MAX_SUBCHANNEL);
  56                 schid.sch_no = 0;
  57         } while (schid.ssid++ < max_ssid);
  58         return ret;
  59 }
  60
  61 struct cb_data {
  62         void *data;
  63         struct idset *set;
  64         int (*fn_known_sch)(struct subchannel *, void *);
  65         int (*fn_unknown_sch)(struct subchannel_id, void *);
  66 };
  67
  68 static int call_fn_known_sch(struct device *dev, void *data)
  69 {
  70         struct subchannel *sch = to_subchannel(dev);
  71         struct cb_data *cb = data;
  72         int rc = 0;
  73
  74         if (cb->set)
  75                 idset_sch_del(cb->set, sch->schid);
  76         if (cb->fn_known_sch)
  77                 rc = cb->fn_known_sch(sch, cb->data);
  78         return rc;
  79 }
  80
  81 static int call_fn_unknown_sch(struct subchannel_id schid, void *data)
  82 {
  83         struct cb_data *cb = data;
  84         int rc = 0;
  85
  86         if (idset_sch_contains(cb->set, schid))
  87                 rc = cb->fn_unknown_sch(schid, cb->data);
  88         return rc;
  89 }
  90
  91 static int call_fn_all_sch(struct subchannel_id schid, void *data)
  92 {
  93         struct cb_data *cb = data;
  94         struct subchannel *sch;
  95         int rc = 0;
  96
  97         sch = get_subchannel_by_schid(schid);
  98         if (sch) {
  99                 if (cb->fn_known_sch)
 100                         rc = cb->fn_known_sch(sch, cb->data);
 101                 put_device(&sch->dev);
 102         } else {
 103                 if (cb->fn_unknown_sch)
 104                         rc = cb->fn_unknown_sch(schid, cb->data);
 105         }
 106
 107         return rc;
 108 }
 109
 110 int for_each_subchannel_staged(int (*fn_known)(struct subchannel *, void *),
 111                                int (*fn_unknown)(struct subchannel_id,
 112                                void *), void *data)
 113 {
 114         struct cb_data cb;
 115         int rc;
 116
 117         cb.data = data;
 118         cb.fn_known_sch = fn_known;
 119         cb.fn_unknown_sch = fn_unknown;
 120
 121         if (fn_known && !fn_unknown) {
 122                 /* Skip idset allocation in case of known-only loop. */
 123                 cb.set = NULL;
 124                 return bus_for_each_dev(&css_bus_type, NULL, &cb,
 125                                         call_fn_known_sch);
 126         }
 127
 128         cb.set = idset_sch_new();
 129         if (!cb.set)
 130                 /* fall back to brute force scanning in case of oom */
 131                 return for_each_subchannel(call_fn_all_sch, &cb);
 132
 133         idset_fill(cb.set);
 134
 135         /* Process registered subchannels. */
 136         rc = bus_for_each_dev(&css_bus_type, NULL, &cb, call_fn_known_sch);
 137         if (rc)
 138                 goto out;
 139         /* Process unregistered subchannels. */
 140         if (fn_unknown)
 141                 rc = for_each_subchannel(call_fn_unknown_sch, &cb);
 142 out:
 143         idset_free(cb.set);
 144
 145         return rc;
 146 }
 147
 148 static void css_sch_todo(struct work_struct *work);
 149
 150 static int css_sch_create_locks(struct subchannel *sch)
 151 {
 152         sch->lock = kmalloc(sizeof(*sch->lock), GFP_KERNEL);
 153         if (!sch->lock)
 154                 return -ENOMEM;
 155
 156         spin_lock_init(sch->lock);
 157         mutex_init(&sch->reg_mutex);
 158
 159         return 0;
 160 }
 161
 162 static void css_subchannel_release(struct device *dev)
 163 {
 164         struct subchannel *sch = to_subchannel(dev);
 165
 166         sch->config.intparm = 0;
 167         cio_commit_config(sch);
 168         kfree(sch->lock);
 169         kfree(sch);
 170 }
 171
 172 struct subchannel *css_alloc_subchannel(struct subchannel_id schid)
 173 {
 174         struct subchannel *sch;
 175         int ret;
 176
 177         sch = kzalloc(sizeof(*sch), GFP_KERNEL | GFP_DMA);
 178         if (!sch)
 179                 return ERR_PTR(-ENOMEM);
 180
 181         ret = cio_validate_subchannel(sch, schid);
 182         if (ret < 0)
 183                 goto err;
 184
 185         ret = css_sch_create_locks(sch);
 186         if (ret)
 187                 goto err;
 188
 189         INIT_WORK(&sch->todo_work, css_sch_todo);
 190         sch->dev.release = &css_subchannel_release;
 191         device_initialize(&sch->dev);
 192         return sch;
 193
 194 err:
 195         kfree(sch);
 196         return ERR_PTR(ret);
 197 }
 198
 199 static int css_sch_device_register(struct subchannel *sch)
 200 {
 201         int ret;
 202
 203         mutex_lock(&sch->reg_mutex);
 204         dev_set_name(&sch->dev, "0.%x.%04x", sch->schid.ssid,
 205                      sch->schid.sch_no);
 206         ret = device_add(&sch->dev);
 207         mutex_unlock(&sch->reg_mutex);
 208         return ret;
 209 }
 210
 211 /**
 212  * css_sch_device_unregister - unregister a subchannel
 213  * @sch: subchannel to be unregistered
 214  */
 215 void css_sch_device_unregister(struct subchannel *sch)
 216 {
 217         mutex_lock(&sch->reg_mutex);
 218         if (device_is_registered(&sch->dev))
 219                 device_unregister(&sch->dev);
 220         mutex_unlock(&sch->reg_mutex);
 221 }
 222 EXPORT_SYMBOL_GPL(css_sch_device_unregister);
 223
 224 static void ssd_from_pmcw(struct chsc_ssd_info *ssd, struct pmcw *pmcw)
 225 {
 226         int i;
 227         int mask;
 228
 229         memset(ssd, 0, sizeof(struct chsc_ssd_info));
 230         ssd->path_mask = pmcw->pim;
 231         for (i = 0; i < 8; i++) {
 232                 mask = 0x80 >> i;
 233                 if (pmcw->pim & mask) {
 234                         chp_id_init(&ssd->chpid[i]);
 235                         ssd->chpid[i].id = pmcw->chpid[i];
 236                 }
 237         }
 238 }
 239
 240 static void ssd_register_chpids(struct chsc_ssd_info *ssd)
 241 {
 242         int i;
 243         int mask;
 244
 245         for (i = 0; i < 8; i++) {
 246                 mask = 0x80 >> i;
 247                 if (ssd->path_mask & mask)
 248                         if (!chp_is_registered(ssd->chpid[i]))
 249                                 chp_new(ssd->chpid[i]);
 250         }
 251 }
 252
 253 void css_update_ssd_info(struct subchannel *sch)
 254 {
 255         int ret;
 256
 257         ret = chsc_get_ssd_info(sch->schid, &sch->ssd_info);
 258         if (ret)
 259                 ssd_from_pmcw(&sch->ssd_info, &sch->schib.pmcw);
 260
 261         ssd_register_chpids(&sch->ssd_info);
 262 }
 263
 264 static ssize_t type_show(struct device *dev, struct device_attribute *attr,
 265                          char *buf)
 266 {
 267         struct subchannel *sch = to_subchannel(dev);
 268
 269         return sprintf(buf, "%01x\n", sch->st);
 270 }
 271
 272 static DEVICE_ATTR(type, 0444, type_show, NULL);
 273
 274 static ssize_t modalias_show(struct device *dev, struct device_attribute *attr,
 275                              char *buf)
 276 {
 277         struct subchannel *sch = to_subchannel(dev);
 278
 279         return sprintf(buf, "css:t%01X\n", sch->st);
 280 }
 281
 282 static DEVICE_ATTR(modalias, 0444, modalias_show, NULL);
 283
 284 static struct attribute *subch_attrs[] = {
 285         &dev_attr_type.attr,
 286         &dev_attr_modalias.attr,
 287         NULL,
 288 };
 289
 290 static struct attribute_group subch_attr_group = {
 291         .attrs = subch_attrs,
 292 };
 293
 294 static const struct attribute_group *default_subch_attr_groups[] = {
 295         &subch_attr_group,
 296         NULL,
 297 };
 298
 299 static ssize_t chpids_show(struct device *dev,
 300                            struct device_attribute *attr,
 301                            char *buf)
 302 {
 303         struct subchannel *sch = to_subchannel(dev);
 304         struct chsc_ssd_info *ssd = &sch->ssd_info;
 305         ssize_t ret = 0;
 306         int mask;
 307         int chp;
 308
 309         for (chp = 0; chp < 8; chp++) {
 310                 mask = 0x80 >> chp;
 311                 if (ssd->path_mask & mask)
 312                         ret += sprintf(buf + ret, "%02x ", ssd->chpid[chp].id);
 313                 else
 314                         ret += sprintf(buf + ret, "00 ");
 315         }
 316         ret += sprintf(buf + ret, "\n");
 317         return ret;
 318 }
 319 static DEVICE_ATTR(chpids, 0444, chpids_show, NULL);
 320
 321 static ssize_t pimpampom_show(struct device *dev,
 322                               struct device_attribute *attr,
 323                               char *buf)
 324 {
 325         struct subchannel *sch = to_subchannel(dev);
 326         struct pmcw *pmcw = &sch->schib.pmcw;
 327
 328         return sprintf(buf, "%02x %02x %02x\n",
 329                        pmcw->pim, pmcw->pam, pmcw->pom);
 330 }
 331 static DEVICE_ATTR(pimpampom, 0444, pimpampom_show, NULL);
 332
 333 static struct attribute *io_subchannel_type_attrs[] = {
 334         &dev_attr_chpids.attr,
 335         &dev_attr_pimpampom.attr,
 336         NULL,
 337 };
 338 ATTRIBUTE_GROUPS(io_subchannel_type);
 339
 340 static const struct device_type io_subchannel_type = {
 341         .groups = io_subchannel_type_groups,
 342 };
 343
 344 int css_register_subchannel(struct subchannel *sch)
 345 {
 346         int ret;
 347
 348         /* Initialize the subchannel structure */
 349         sch->dev.parent = &channel_subsystems[0]->device;
 350         sch->dev.bus = &css_bus_type;
 351         sch->dev.groups = default_subch_attr_groups;
 352
 353         if (sch->st == SUBCHANNEL_TYPE_IO)
 354                 sch->dev.type = &io_subchannel_type;
 355
 356         /*
 357          * We don't want to generate uevents for I/O subchannels that don't
 358          * have a working ccw device behind them since they will be
 359          * unregistered before they can be used anyway, so we delay the add
 360          * uevent until after device recognition was successful.
 361          * Note that we suppress the uevent for all subchannel types;
 362          * the subchannel driver can decide itself when it wants to inform
 363          * userspace of its existence.
 364          */
 365         dev_set_uevent_suppress(&sch->dev, 1);
 366         css_update_ssd_info(sch);
 367         /* make it known to the system */
 368         ret = css_sch_device_register(sch);
 369         if (ret) {
 370                 CIO_MSG_EVENT(0, "Could not register sch 0.%x.%04x: %d\n",
 371                               sch->schid.ssid, sch->schid.sch_no, ret);
 372                 return ret;
 373         }
 374         if (!sch->driver) {
 375                 /*
 376                  * No driver matched. Generate the uevent now so that
 377                  * a fitting driver module may be loaded based on the
 378                  * modalias.
 379                  */
 380                 dev_set_uevent_suppress(&sch->dev, 0);
 381                 kobject_uevent(&sch->dev.kobj, KOBJ_ADD);
 382         }
 383         return ret;
 384 }
 385
 386 static int css_probe_device(struct subchannel_id schid)
 387 {
 388         struct subchannel *sch;
 389         int ret;
 390
 391         sch = css_alloc_subchannel(schid);
 392         if (IS_ERR(sch))
 393                 return PTR_ERR(sch);
 394
 395         ret = css_register_subchannel(sch);
 396         if (ret)
 397                 put_device(&sch->dev);
 398
 399         return ret;
 400 }
 401
 402 static int
 403 check_subchannel(struct device * dev, void * data)
 404 {
 405         struct subchannel *sch;
 406         struct subchannel_id *schid = data;
 407
 408         sch = to_subchannel(dev);
 409         return schid_equal(&sch->schid, schid);
 410 }
 411
 412 struct subchannel *
 413 get_subchannel_by_schid(struct subchannel_id schid)
 414 {
 415         struct device *dev;
 416
 417         dev = bus_find_device(&css_bus_type, NULL,
 418                               &schid, check_subchannel);
 419
 420         return dev ? to_subchannel(dev) : NULL;
 421 }
 422
 423 /**
 424  * css_sch_is_valid() - check if a subchannel is valid
 425  * @schib: subchannel information block for the subchannel
 426  */
 427 int css_sch_is_valid(struct schib *schib)
 428 {
 429         if ((schib->pmcw.st == SUBCHANNEL_TYPE_IO) && !schib->pmcw.dnv)
 430                 return 0;
 431         if ((schib->pmcw.st == SUBCHANNEL_TYPE_MSG) && !schib->pmcw.w)
 432                 return 0;
 433         return 1;
 434 }
 435 EXPORT_SYMBOL_GPL(css_sch_is_valid);
 436
 437 static int css_evaluate_new_subchannel(struct subchannel_id schid, int slow)
 438 {
 439         struct schib schib;
 440
 441         if (!slow) {
 442                 /* Will be done on the slow path. */
 443                 return -EAGAIN;
 444         }
 445         if (stsch(schid, &schib)) {
 446                 /* Subchannel is not provided. */
 447                 return -ENXIO;
 448         }
 449         if (!css_sch_is_valid(&schib)) {
 450                 /* Unusable - ignore. */
 451                 return 0;
 452         }
 453         CIO_MSG_EVENT(4, "event: sch 0.%x.%04x, new\n", schid.ssid,
 454                       schid.sch_no);
 455
 456         return css_probe_device(schid);
 457 }
 458
 459 static int css_evaluate_known_subchannel(struct subchannel *sch, int slow)
 460 {
 461         int ret = 0;
 462
 463         if (sch->driver) {
 464                 if (sch->driver->sch_event)
 465                         ret = sch->driver->sch_event(sch, slow);
 466                 else
 467                         dev_dbg(&sch->dev,
 468                                 "Got subchannel machine check but "
 469                                 "no sch_event handler provided.\n");
 470         }
 471         if (ret != 0 && ret != -EAGAIN) {
 472                 CIO_MSG_EVENT(2, "eval: sch 0.%x.%04x, rc=%d\n",
 473                               sch->schid.ssid, sch->schid.sch_no, ret);
 474         }
 475         return ret;
 476 }
 477
 478 static void css_evaluate_subchannel(struct subchannel_id schid, int slow)
 479 {
 480         struct subchannel *sch;
 481         int ret;
 482
 483         sch = get_subchannel_by_schid(schid);
 484         if (sch) {
 485                 ret = css_evaluate_known_subchannel(sch, slow);
 486                 put_device(&sch->dev);
 487         } else
 488                 ret = css_evaluate_new_subchannel(schid, slow);
 489         if (ret == -EAGAIN)
 490                 css_schedule_eval(schid);
 491 }
 492
 493 /**
 494  * css_sched_sch_todo - schedule a subchannel operation
 495  * @sch: subchannel
 496  * @todo: todo
 497  *
 498  * Schedule the operation identified by @todo to be performed on the slow path
 499  * workqueue. Do nothing if another operation with higher priority is already
 500  * scheduled. Needs to be called with subchannel lock held.
 501  */
 502 void css_sched_sch_todo(struct subchannel *sch, enum sch_todo todo)
 503 {
 504         CIO_MSG_EVENT(4, "sch_todo: sched sch=0.%x.%04x todo=%d\n",
 505                       sch->schid.ssid, sch->schid.sch_no, todo);
 506         if (sch->todo >= todo)
 507                 return;
 508         /* Get workqueue ref. */
 509         if (!get_device(&sch->dev))
 510                 return;
 511         sch->todo = todo;
 512         if (!queue_work(cio_work_q, &sch->todo_work)) {
 513                 /* Already queued, release workqueue ref. */
 514                 put_device(&sch->dev);
 515         }
 516 }
 517 EXPORT_SYMBOL_GPL(css_sched_sch_todo);
 518
 519 static void css_sch_todo(struct work_struct *work)
 520 {
 521         struct subchannel *sch;
 522         enum sch_todo todo;
 523         int ret;
 524
 525         sch = container_of(work, struct subchannel, todo_work);
 526         /* Find out todo. */
 527         spin_lock_irq(sch->lock);
 528         todo = sch->todo;
 529         CIO_MSG_EVENT(4, "sch_todo: sch=0.%x.%04x, todo=%d\n", sch->schid.ssid,
 530                       sch->schid.sch_no, todo);
 531         sch->todo = SCH_TODO_NOTHING;
 532         spin_unlock_irq(sch->lock);
 533         /* Perform todo. */
 534         switch (todo) {
 535         case SCH_TODO_NOTHING:
 536                 break;
 537         case SCH_TODO_EVAL:
 538                 ret = css_evaluate_known_subchannel(sch, 1);
 539                 if (ret == -EAGAIN) {
 540                         spin_lock_irq(sch->lock);
 541                         css_sched_sch_todo(sch, todo);
 542                         spin_unlock_irq(sch->lock);
 543                 }
 544                 break;
 545         case SCH_TODO_UNREG:
 546                 css_sch_device_unregister(sch);
 547                 break;
 548         }
 549         /* Release workqueue ref. */
 550         put_device(&sch->dev);
 551 }
 552
 553 static struct idset *slow_subchannel_set;
 554 static spinlock_t slow_subchannel_lock;
 555 static wait_queue_head_t css_eval_wq;
 556 static atomic_t css_eval_scheduled;
 557
 558 static int __init slow_subchannel_init(void)
 559 {
 560         spin_lock_init(&slow_subchannel_lock);
 561         atomic_set(&css_eval_scheduled, 0);
 562         init_waitqueue_head(&css_eval_wq);
 563         slow_subchannel_set = idset_sch_new();
 564         if (!slow_subchannel_set) {
 565                 CIO_MSG_EVENT(0, "could not allocate slow subchannel set\n");
 566                 return -ENOMEM;
 567         }
 568         return 0;
 569 }
 570
 571 static int slow_eval_known_fn(struct subchannel *sch, void *data)
 572 {
 573         int eval;
 574         int rc;
 575
 576         spin_lock_irq(&slow_subchannel_lock);
 577         eval = idset_sch_contains(slow_subchannel_set, sch->schid);
 578         idset_sch_del(slow_subchannel_set, sch->schid);
 579         spin_unlock_irq(&slow_subchannel_lock);
 580         if (eval) {
 581                 rc = css_evaluate_known_subchannel(sch, 1);
 582                 if (rc == -EAGAIN)
 583                         css_schedule_eval(sch->schid);
 584         }
 585         return 0;
 586 }
 587
 588 static int slow_eval_unknown_fn(struct subchannel_id schid, void *data)
 589 {
 590         int eval;
 591         int rc = 0;
 592
 593         spin_lock_irq(&slow_subchannel_lock);
 594         eval = idset_sch_contains(slow_subchannel_set, schid);
 595         idset_sch_del(slow_subchannel_set, schid);
 596         spin_unlock_irq(&slow_subchannel_lock);
 597         if (eval) {
 598                 rc = css_evaluate_new_subchannel(schid, 1);
 599                 switch (rc) {
 600                 case -EAGAIN:
 601                         css_schedule_eval(schid);
 602                         rc = 0;
 603                         break;
 604                 case -ENXIO:
 605                 case -ENOMEM:
 606                 case -EIO:
 607                         /* These should abort looping */
 608                         spin_lock_irq(&slow_subchannel_lock);
 609                         idset_sch_del_subseq(slow_subchannel_set, schid);
 610                         spin_unlock_irq(&slow_subchannel_lock);
 611                         break;
 612                 default:
 613                         rc = 0;
 614                 }
 615                 /* Allow scheduling here since the containing loop might
 616                  * take a while.  */
 617                 cond_resched();
 618         }
 619         return rc;
 620 }
 621
 622 static void css_slow_path_func(struct work_struct *unused)
 623 {
 624         unsigned long flags;
 625
 626         CIO_TRACE_EVENT(4, "slowpath");
 627         for_each_subchannel_staged(slow_eval_known_fn, slow_eval_unknown_fn,
 628                                    NULL);
 629         spin_lock_irqsave(&slow_subchannel_lock, flags);
 630         if (idset_is_empty(slow_subchannel_set)) {
 631                 atomic_set(&css_eval_scheduled, 0);
 632                 wake_up(&css_eval_wq);
 633         }
 634         spin_unlock_irqrestore(&slow_subchannel_lock, flags);
 635 }
 636
 637 static DECLARE_DELAYED_WORK(slow_path_work, css_slow_path_func);
 638 struct workqueue_struct *cio_work_q;
 639
 640 void css_schedule_eval(struct subchannel_id schid)
 641 {
 642         unsigned long flags;
 643
 644         spin_lock_irqsave(&slow_subchannel_lock, flags);
 645         idset_sch_add(slow_subchannel_set, schid);
 646         atomic_set(&css_eval_scheduled, 1);
 647         queue_delayed_work(cio_work_q, &slow_path_work, 0);
 648         spin_unlock_irqrestore(&slow_subchannel_lock, flags);
 649 }
 650
 651 void css_schedule_eval_all(void)
 652 {
 653         unsigned long flags;
 654
 655         spin_lock_irqsave(&slow_subchannel_lock, flags);
 656         idset_fill(slow_subchannel_set);
 657         atomic_set(&css_eval_scheduled, 1);
 658         queue_delayed_work(cio_work_q, &slow_path_work, 0);
 659         spin_unlock_irqrestore(&slow_subchannel_lock, flags);
 660 }
 661
 662 static int __unset_registered(struct device *dev, void *data)
 663 {
 664         struct idset *set = data;
 665         struct subchannel *sch = to_subchannel(dev);
 666
 667         idset_sch_del(set, sch->schid);
 668         return 0;
 669 }
 670
 671 void css_schedule_eval_all_unreg(unsigned long delay)
 672 {
 673         unsigned long flags;
 674         struct idset *unreg_set;
 675
 676         /* Find unregistered subchannels. */
 677         unreg_set = idset_sch_new();
 678         if (!unreg_set) {
 679                 /* Fallback. */
 680                 css_schedule_eval_all();
 681                 return;
 682         }
 683         idset_fill(unreg_set);
 684         bus_for_each_dev(&css_bus_type, NULL, unreg_set, __unset_registered);
 685         /* Apply to slow_subchannel_set. */
 686         spin_lock_irqsave(&slow_subchannel_lock, flags);
 687         idset_add_set(slow_subchannel_set, unreg_set);
 688         atomic_set(&css_eval_scheduled, 1);
 689         queue_delayed_work(cio_work_q, &slow_path_work, delay);
 690         spin_unlock_irqrestore(&slow_subchannel_lock, flags);
 691         idset_free(unreg_set);
 692 }
 693
 694 void css_wait_for_slow_path(void)
 695 {
 696         flush_workqueue(cio_work_q);
 697 }
 698
 699 /* Schedule reprobing of all unregistered subchannels. */
 700 void css_schedule_reprobe(void)
 701 {
 702         /* Schedule with a delay to allow merging of subsequent calls. */
 703         css_schedule_eval_all_unreg(1 * HZ);
 704 }
 705 EXPORT_SYMBOL_GPL(css_schedule_reprobe);
 706
 707 /*
 708  * Called from the machine check handler for subchannel report words.
 709  */
 710 static void css_process_crw(struct crw *crw0, struct crw *crw1, int overflow)
 711 {
 712         struct subchannel_id mchk_schid;
 713         struct subchannel *sch;
 714
 715         if (overflow) {
 716                 css_schedule_eval_all();
 717                 return;
 718         }
 719         CIO_CRW_EVENT(2, "CRW0 reports slct=%d, oflw=%d, "
 720                       "chn=%d, rsc=%X, anc=%d, erc=%X, rsid=%X\n",
 721                       crw0->slct, crw0->oflw, crw0->chn, crw0->rsc, crw0->anc,
 722                       crw0->erc, crw0->rsid);
 723         if (crw1)
 724                 CIO_CRW_EVENT(2, "CRW1 reports slct=%d, oflw=%d, "
 725                               "chn=%d, rsc=%X, anc=%d, erc=%X, rsid=%X\n",
 726                               crw1->slct, crw1->oflw, crw1->chn, crw1->rsc,
 727                               crw1->anc, crw1->erc, crw1->rsid);
 728         init_subchannel_id(&mchk_schid);
 729         mchk_schid.sch_no = crw0->rsid;
 730         if (crw1)
 731                 mchk_schid.ssid = (crw1->rsid >> 4) & 3;
 732
 733         if (crw0->erc == CRW_ERC_PMOD) {
 734                 sch = get_subchannel_by_schid(mchk_schid);
 735                 if (sch) {
 736                         css_update_ssd_info(sch);
 737                         put_device(&sch->dev);
 738                 }
 739         }
 740         /*
 741          * Since we are always presented with IPI in the CRW, we have to
 742          * use stsch() to find out if the subchannel in question has come
 743          * or gone.
 744          */
 745         css_evaluate_subchannel(mchk_schid, 0);
 746 }
 747
 748 static void __init
 749 css_generate_pgid(struct channel_subsystem *css, u32 tod_high)
 750 {
 751         struct cpuid cpu_id;
 752
 753         if (css_general_characteristics.mcss) {
 754                 css->global_pgid.pgid_high.ext_cssid.version = 0x80;
 755                 css->global_pgid.pgid_high.ext_cssid.cssid =
 756                         (css->cssid < 0) ? 0 : css->cssid;
 757         } else {
 758                 css->global_pgid.pgid_high.cpu_addr = stap();
 759         }
 760         get_cpu_id(&cpu_id);
 761         css->global_pgid.cpu_id = cpu_id.ident;
 762         css->global_pgid.cpu_model = cpu_id.machine;
 763         css->global_pgid.tod_high = tod_high;
 764 }
 765
 766 static void channel_subsystem_release(struct device *dev)
 767 {
 768         struct channel_subsystem *css = to_css(dev);
 769
 770         mutex_destroy(&css->mutex);
 771         kfree(css);
 772 }
 773
 774 static ssize_t real_cssid_show(struct device *dev, struct device_attribute *a,
 775                                char *buf)
 776 {
 777         struct channel_subsystem *css = to_css(dev);
 778
 779         if (css->cssid < 0)
 780                 return -EINVAL;
 781
 782         return sprintf(buf, "%x\n", css->cssid);
 783 }
 784 static DEVICE_ATTR_RO(real_cssid);
 785
 786 static ssize_t cm_enable_show(struct device *dev, struct device_attribute *a,
 787                               char *buf)
 788 {
 789         struct channel_subsystem *css = to_css(dev);
 790         int ret;
 791
 792         mutex_lock(&css->mutex);
 793         ret = sprintf(buf, "%x\n", css->cm_enabled);
 794         mutex_unlock(&css->mutex);
 795         return ret;
 796 }
 797
 798 static ssize_t cm_enable_store(struct device *dev, struct device_attribute *a,
 799                                const char *buf, size_t count)
 800 {
 801         struct channel_subsystem *css = to_css(dev);
 802         unsigned long val;
 803         int ret;
 804
 805         ret = kstrtoul(buf, 16, &val);
 806         if (ret)
 807                 return ret;
 808         mutex_lock(&css->mutex);
 809         switch (val) {
 810         case 0:
 811                 ret = css->cm_enabled ? chsc_secm(css, 0) : 0;
 812                 break;
 813         case 1:
 814                 ret = css->cm_enabled ? 0 : chsc_secm(css, 1);
 815                 break;
 816         default:
 817                 ret = -EINVAL;
 818         }
 819         mutex_unlock(&css->mutex);
 820         return ret < 0 ? ret : count;
 821 }
 822 static DEVICE_ATTR_RW(cm_enable);
 823
 824 static umode_t cm_enable_mode(struct kobject *kobj, struct attribute *attr,
 825                               int index)
 826 {
 827         return css_chsc_characteristics.secm ? attr->mode : 0;
 828 }
 829
 830 static struct attribute *cssdev_attrs[] = {
 831         &dev_attr_real_cssid.attr,
 832         NULL,
 833 };
 834
 835 static struct attribute_group cssdev_attr_group = {
 836         .attrs = cssdev_attrs,
 837 };
 838
 839 static struct attribute *cssdev_cm_attrs[] = {
 840         &dev_attr_cm_enable.attr,
 841         NULL,
 842 };
 843
 844 static struct attribute_group cssdev_cm_attr_group = {
 845         .attrs = cssdev_cm_attrs,
 846         .is_visible = cm_enable_mode,
 847 };
 848
 849 static const struct attribute_group *cssdev_attr_groups[] = {
 850         &cssdev_attr_group,
 851         &cssdev_cm_attr_group,
 852         NULL,
 853 };
 854
 855 static int __init setup_css(int nr)
 856 {
 857         struct channel_subsystem *css;
 858         int ret;
 859
 860         css = kzalloc(sizeof(*css), GFP_KERNEL);
 861         if (!css)
 862                 return -ENOMEM;
 863
 864         channel_subsystems[nr] = css;
 865         dev_set_name(&css->device, "css%x", nr);
 866         css->device.groups = cssdev_attr_groups;
 867         css->device.release = channel_subsystem_release;
 868
 869         mutex_init(&css->mutex);
 870         css->cssid = chsc_get_cssid(nr);
 871         css_generate_pgid(css, (u32) (get_tod_clock() >> 32));
 872
 873         ret = device_register(&css->device);
 874         if (ret) {
 875                 put_device(&css->device);
 876                 goto out_err;
 877         }
 878
 879         css->pseudo_subchannel = kzalloc(sizeof(*css->pseudo_subchannel),
 880                                          GFP_KERNEL);
 881         if (!css->pseudo_subchannel) {
 882                 device_unregister(&css->device);
 883                 ret = -ENOMEM;
 884                 goto out_err;
 885         }
 886
 887         css->pseudo_subchannel->dev.parent = &css->device;
 888         css->pseudo_subchannel->dev.release = css_subchannel_release;
 889         mutex_init(&css->pseudo_subchannel->reg_mutex);
 890         ret = css_sch_create_locks(css->pseudo_subchannel);
 891         if (ret) {
 892                 kfree(css->pseudo_subchannel);
 893                 device_unregister(&css->device);
 894                 goto out_err;
 895         }
 896
 897         dev_set_name(&css->pseudo_subchannel->dev, "defunct");
 898         ret = device_register(&css->pseudo_subchannel->dev);
 899         if (ret) {
 900                 put_device(&css->pseudo_subchannel->dev);
 901                 device_unregister(&css->device);
 902                 goto out_err;
 903         }
 904
 905         return ret;
 906 out_err:
 907         channel_subsystems[nr] = NULL;
 908         return ret;
 909 }
 910
 911 static int css_reboot_event(struct notifier_block *this,
 912                             unsigned long event,
 913                             void *ptr)
 914 {
 915         struct channel_subsystem *css;
 916         int ret;
 917
 918         ret = NOTIFY_DONE;
 919         for_each_css(css) {
 920                 mutex_lock(&css->mutex);
 921                 if (css->cm_enabled)
 922                         if (chsc_secm(css, 0))
 923                                 ret = NOTIFY_BAD;
 924                 mutex_unlock(&css->mutex);
 925         }
 926
 927         return ret;
 928 }
 929
 930 static struct notifier_block css_reboot_notifier = {
 931         .notifier_call = css_reboot_event,
 932 };
 933
 934 /*
 935  * Since the css devices are neither on a bus nor have a class
 936  * nor have a special device type, we cannot stop/restart channel
 937  * path measurements via the normal suspend/resume callbacks, but have
 938  * to use notifiers.
 939  */
 940 static int css_power_event(struct notifier_block *this, unsigned long event,
 941                            void *ptr)
 942 {
 943         struct channel_subsystem *css;
 944         int ret;
 945
 946         switch (event) {
 947         case PM_HIBERNATION_PREPARE:
 948         case PM_SUSPEND_PREPARE:
 949                 ret = NOTIFY_DONE;
 950                 for_each_css(css) {
 951                         mutex_lock(&css->mutex);
 952                         if (!css->cm_enabled) {
 953                                 mutex_unlock(&css->mutex);
 954                                 continue;
 955                         }
 956                         ret = __chsc_do_secm(css, 0);
 957                         ret = notifier_from_errno(ret);
 958                         mutex_unlock(&css->mutex);
 959                 }
 960                 break;
 961         case PM_POST_HIBERNATION:
 962         case PM_POST_SUSPEND:
 963                 ret = NOTIFY_DONE;
 964                 for_each_css(css) {
 965                         mutex_lock(&css->mutex);
 966                         if (!css->cm_enabled) {
 967                                 mutex_unlock(&css->mutex);
 968                                 continue;
 969                         }
 970                         ret = __chsc_do_secm(css, 1);
 971                         ret = notifier_from_errno(ret);
 972                         mutex_unlock(&css->mutex);
 973                 }
 974                 /* search for subchannels, which appeared during hibernation */
 975                 css_schedule_reprobe();
 976                 break;
 977         default:
 978                 ret = NOTIFY_DONE;
 979         }
 980         return ret;
 981
 982 }
 983 static struct notifier_block css_power_notifier = {
 984         .notifier_call = css_power_event,
 985 };
 986
 987 /*
 988  * Now that the driver core is running, we can setup our channel subsystem.
 989  * The struct subchannel's are created during probing.
 990  */
 991 static int __init css_bus_init(void)
 992 {
 993         int ret, i;
 994
 995         ret = chsc_init();
 996         if (ret)
 997                 return ret;
 998
 999         chsc_determine_css_characteristics();
1000         /* Try to enable MSS. */
1001         ret = chsc_enable_facility(CHSC_SDA_OC_MSS);
1002         if (ret)
1003                 max_ssid = 0;
1004         else /* Success. */
1005                 max_ssid = __MAX_SSID;
1006
1007         ret = slow_subchannel_init();
1008         if (ret)
1009                 goto out;
1010
1011         ret = crw_register_handler(CRW_RSC_SCH, css_process_crw);
1012         if (ret)
1013                 goto out;
1014
1015         if ((ret = bus_register(&css_bus_type)))
1016                 goto out;
1017
1018         /* Setup css structure. */
1019         for (i = 0; i <= MAX_CSS_IDX; i++) {
1020                 ret = setup_css(i);
1021                 if (ret)
1022                         goto out_unregister;
1023         }
1024         ret = register_reboot_notifier(&css_reboot_notifier);
1025         if (ret)
1026                 goto out_unregister;
1027         ret = register_pm_notifier(&css_power_notifier);
1028         if (ret) {
1029                 unregister_reboot_notifier(&css_reboot_notifier);
1030                 goto out_unregister;
1031         }
1032         css_init_done = 1;
1033
1034         /* Enable default isc for I/O subchannels. */
1035         isc_register(IO_SCH_ISC);
1036
1037         return 0;
1038 out_unregister:
1039         while (i-- > 0) {
1040                 struct channel_subsystem *css = channel_subsystems[i];
1041                 device_unregister(&css->pseudo_subchannel->dev);
1042                 device_unregister(&css->device);
1043         }
1044         bus_unregister(&css_bus_type);
1045 out:
1046         crw_unregister_handler(CRW_RSC_SCH);
1047         idset_free(slow_subchannel_set);
1048         chsc_init_cleanup();
1049         pr_alert("The CSS device driver initialization failed with "
1050                  "errno=%d\n", ret);
1051         return ret;
1052 }
1053
1054 static void __init css_bus_cleanup(void)
1055 {
1056         struct channel_subsystem *css;
1057
1058         for_each_css(css) {
1059                 device_unregister(&css->pseudo_subchannel->dev);
1060                 device_unregister(&css->device);
1061         }
1062         bus_unregister(&css_bus_type);
1063         crw_unregister_handler(CRW_RSC_SCH);
1064         idset_free(slow_subchannel_set);
1065         chsc_init_cleanup();
1066         isc_unregister(IO_SCH_ISC);
1067 }
1068
1069 static int __init channel_subsystem_init(void)
1070 {
1071         int ret;
1072
1073         ret = css_bus_init();
1074         if (ret)
1075                 return ret;
1076         cio_work_q = create_singlethread_workqueue("cio");
1077         if (!cio_work_q) {
1078                 ret = -ENOMEM;
1079                 goto out_bus;
1080         }
1081         ret = io_subchannel_init();
1082         if (ret)
1083                 goto out_wq;
1084
1085         return ret;
1086 out_wq:
1087         destroy_workqueue(cio_work_q);
1088 out_bus:
1089         css_bus_cleanup();
1090         return ret;
1091 }
1092 subsys_initcall(channel_subsystem_init);
1093
1094 static int css_settle(struct device_driver *drv, void *unused)
1095 {
1096         struct css_driver *cssdrv = to_cssdriver(drv);
1097
1098         if (cssdrv->settle)
1099                 return cssdrv->settle();
1100         return 0;
1101 }
1102
1103 int css_complete_work(void)
1104 {
1105         int ret;
1106
1107         /* Wait for the evaluation of subchannels to finish. */
1108         ret = wait_event_interruptible(css_eval_wq,
1109                                        atomic_read(&css_eval_scheduled) == 0);
1110         if (ret)
1111                 return -EINTR;
1112         flush_workqueue(cio_work_q);
1113         /* Wait for the subchannel type specific initialization to finish */
1114         return bus_for_each_drv(&css_bus_type, NULL, NULL, css_settle);
1115 }
1116
1117
1118 /*
1119  * Wait for the initialization of devices to finish, to make sure we are
1120  * done with our setup if the search for the root device starts.
1121  */
1122 static int __init channel_subsystem_init_sync(void)
1123 {
1124         /* Register subchannels which are already in use. */
1125         cio_register_early_subchannels();
1126         /* Start initial subchannel evaluation. */
1127         css_schedule_eval_all();
1128         css_complete_work();
1129         return 0;
1130 }
1131 subsys_initcall_sync(channel_subsystem_init_sync);
1132
1133 void channel_subsystem_reinit(void)
1134 {
1135         struct channel_path *chp;
1136         struct chp_id chpid;
1137
1138         chsc_enable_facility(CHSC_SDA_OC_MSS);
1139         chp_id_for_each(&chpid) {
1140                 chp = chpid_to_chp(chpid);
1141                 if (chp)
1142                         chp_update_desc(chp);
1143         }
1144         cmf_reactivate();
1145 }
1146
1147 #ifdef CONFIG_PROC_FS
1148 static ssize_t cio_settle_write(struct file *file, const char __user *buf,
1149                                 size_t count, loff_t *ppos)
1150 {
1151         int ret;
1152
1153         /* Handle pending CRW's. */
1154         crw_wait_for_channel_report();
1155         ret = css_complete_work();
1156
1157         return ret ? ret : count;
1158 }
1159
1160 static const struct file_operations cio_settle_proc_fops = {
1161         .open = nonseekable_open,
1162         .write = cio_settle_write,
1163         .llseek = no_llseek,
1164 };
1165
1166 static int __init cio_settle_init(void)
1167 {
1168         struct proc_dir_entry *entry;
1169
1170         entry = proc_create("cio_settle", S_IWUSR, NULL,
1171                             &cio_settle_proc_fops);
1172         if (!entry)
1173                 return -ENOMEM;
1174         return 0;
1175 }
1176 device_initcall(cio_settle_init);
1177 #endif /*CONFIG_PROC_FS*/
1178
1179 int sch_is_pseudo_sch(struct subchannel *sch)
1180 {
1181         return sch == to_css(sch->dev.parent)->pseudo_subchannel;
1182 }
1183
1184 static int css_bus_match(struct device *dev, struct device_driver *drv)
1185 {
1186         struct subchannel *sch = to_subchannel(dev);
1187         struct css_driver *driver = to_cssdriver(drv);
1188         struct css_device_id *id;
1189
1190         for (id = driver->subchannel_type; id->match_flags; id++) {
1191                 if (sch->st == id->type)
1192                         return 1;
1193         }
1194
1195         return 0;
1196 }
1197
1198 static int css_probe(struct device *dev)
1199 {
1200         struct subchannel *sch;
1201         int ret;
1202
1203         sch = to_subchannel(dev);
1204         sch->driver = to_cssdriver(dev->driver);
1205         ret = sch->driver->probe ? sch->driver->probe(sch) : 0;
1206         if (ret)
1207                 sch->driver = NULL;
1208         return ret;
1209 }
1210
1211 static int css_remove(struct device *dev)
1212 {
1213         struct subchannel *sch;
1214         int ret;
1215
1216         sch = to_subchannel(dev);
1217         ret = sch->driver->remove ? sch->driver->remove(sch) : 0;
1218         sch->driver = NULL;
1219         return ret;
1220 }
1221
1222 static void css_shutdown(struct device *dev)
1223 {
1224         struct subchannel *sch;
1225
1226         sch = to_subchannel(dev);
1227         if (sch->driver && sch->driver->shutdown)
1228                 sch->driver->shutdown(sch);
1229 }
1230
1231 static int css_uevent(struct device *dev, struct kobj_uevent_env *env)
1232 {
1233         struct subchannel *sch = to_subchannel(dev);
1234         int ret;
1235
1236         ret = add_uevent_var(env, "ST=%01X", sch->st);
1237         if (ret)
1238                 return ret;
1239         ret = add_uevent_var(env, "MODALIAS=css:t%01X", sch->st);
1240         return ret;
1241 }
1242
1243 static int css_pm_prepare(struct device *dev)
1244 {
1245         struct subchannel *sch = to_subchannel(dev);
1246         struct css_driver *drv;
1247
1248         if (mutex_is_locked(&sch->reg_mutex))
1249                 return -EAGAIN;
1250         if (!sch->dev.driver)
1251                 return 0;
1252         drv = to_cssdriver(sch->dev.driver);
1253         /* Notify drivers that they may not register children. */
1254         return drv->prepare ? drv->prepare(sch) : 0;
1255 }
1256
1257 static void css_pm_complete(struct device *dev)
1258 {
1259         struct subchannel *sch = to_subchannel(dev);
1260         struct css_driver *drv;
1261
1262         if (!sch->dev.driver)
1263                 return;
1264         drv = to_cssdriver(sch->dev.driver);
1265         if (drv->complete)
1266                 drv->complete(sch);
1267 }
1268
1269 static int css_pm_freeze(struct device *dev)
1270 {
1271         struct subchannel *sch = to_subchannel(dev);
1272         struct css_driver *drv;
1273
1274         if (!sch->dev.driver)
1275                 return 0;
1276         drv = to_cssdriver(sch->dev.driver);
1277         return drv->freeze ? drv->freeze(sch) : 0;
1278 }
1279
1280 static int css_pm_thaw(struct device *dev)
1281 {
1282         struct subchannel *sch = to_subchannel(dev);
1283         struct css_driver *drv;
1284
1285         if (!sch->dev.driver)
1286                 return 0;
1287         drv = to_cssdriver(sch->dev.driver);
1288         return drv->thaw ? drv->thaw(sch) : 0;
1289 }
1290
1291 static int css_pm_restore(struct device *dev)
1292 {
1293         struct subchannel *sch = to_subchannel(dev);
1294         struct css_driver *drv;
1295
1296         css_update_ssd_info(sch);
1297         if (!sch->dev.driver)
1298                 return 0;
1299         drv = to_cssdriver(sch->dev.driver);
1300         return drv->restore ? drv->restore(sch) : 0;
1301 }
1302
1303 static const struct dev_pm_ops css_pm_ops = {
1304         .prepare = css_pm_prepare,
1305         .complete = css_pm_complete,
1306         .freeze = css_pm_freeze,
1307         .thaw = css_pm_thaw,
1308         .restore = css_pm_restore,
1309 };
1310
1311 static struct bus_type css_bus_type = {
1312         .name     = "css",
1313         .match    = css_bus_match,
1314         .probe    = css_probe,
1315         .remove   = css_remove,
1316         .shutdown = css_shutdown,
1317         .uevent   = css_uevent,
1318         .pm = &css_pm_ops,
1319 };
1320
1321 /**
1322  * css_driver_register - register a css driver
1323  * @cdrv: css driver to register
1324  *
1325  * This is mainly a wrapper around driver_register that sets name
1326  * and bus_type in the embedded struct device_driver correctly.
1327  */
1328 int css_driver_register(struct css_driver *cdrv)
1329 {
1330         cdrv->drv.bus = &css_bus_type;
1331         return driver_register(&cdrv->drv);
1332 }
1333 EXPORT_SYMBOL_GPL(css_driver_register);
1334
1335 /**
1336  * css_driver_unregister - unregister a css driver
1337  * @cdrv: css driver to unregister
1338  *
1339  * This is a wrapper around driver_unregister.
1340  */
1341 void css_driver_unregister(struct css_driver *cdrv)
1342 {
1343         driver_unregister(&cdrv->drv);
1344 }
1345 EXPORT_SYMBOL_GPL(css_driver_unregister);