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