drivers/s390/cio/css.c

   1 /*
   2  * driver for channel subsystem
   3  *
   4  * Copyright IBM Corp. 2002, 2009
   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 <asm/isc.h>
  22 #include <asm/crw.h>
  23
  24 #include "css.h"
  25 #include "cio.h"
  26 #include "cio_debug.h"
  27 #include "ioasm.h"
  28 #include "chsc.h"
  29 #include "device.h"
  30 #include "idset.h"
  31 #include "chp.h"
  32
  33 int css_init_done = 0;
  34 int max_ssid;
  35
  36 struct channel_subsystem *channel_subsystems[__MAX_CSSID + 1];
  37
  38 int
  39 for_each_subchannel(int(*fn)(struct subchannel_id, void *), void *data)
  40 {
  41         struct subchannel_id schid;
  42         int ret;
  43
  44         init_subchannel_id(&schid);
  45         ret = -ENODEV;
  46         do {
  47                 do {
  48                         ret = fn(schid, data);
  49                         if (ret)
  50                                 break;
  51                 } while (schid.sch_no++ < __MAX_SUBCHANNEL);
  52                 schid.sch_no = 0;
  53         } while (schid.ssid++ < max_ssid);
  54         return ret;
  55 }
  56
  57 struct cb_data {
  58         void *data;
  59         struct idset *set;
  60         int (*fn_known_sch)(struct subchannel *, void *);
  61         int (*fn_unknown_sch)(struct subchannel_id, void *);
  62 };
  63
  64 static int call_fn_known_sch(struct device *dev, void *data)
  65 {
  66         struct subchannel *sch = to_subchannel(dev);
  67         struct cb_data *cb = data;
  68         int rc = 0;
  69
  70         idset_sch_del(cb->set, sch->schid);
  71         if (cb->fn_known_sch)
  72                 rc = cb->fn_known_sch(sch, cb->data);
  73         return rc;
  74 }
  75
  76 static int call_fn_unknown_sch(struct subchannel_id schid, void *data)
  77 {
  78         struct cb_data *cb = data;
  79         int rc = 0;
  80
  81         if (idset_sch_contains(cb->set, schid))
  82                 rc = cb->fn_unknown_sch(schid, cb->data);
  83         return rc;
  84 }
  85
  86 static int call_fn_all_sch(struct subchannel_id schid, void *data)
  87 {
  88         struct cb_data *cb = data;
  89         struct subchannel *sch;
  90         int rc = 0;
  91
  92         sch = get_subchannel_by_schid(schid);
  93         if (sch) {
  94                 if (cb->fn_known_sch)
  95                         rc = cb->fn_known_sch(sch, cb->data);
  96                 put_device(&sch->dev);
  97         } else {
  98                 if (cb->fn_unknown_sch)
  99                         rc = cb->fn_unknown_sch(schid, cb->data);
 100         }
 101
 102         return rc;
 103 }
 104
 105 int for_each_subchannel_staged(int (*fn_known)(struct subchannel *, void *),
 106                                int (*fn_unknown)(struct subchannel_id,
 107                                void *), void *data)
 108 {
 109         struct cb_data cb;
 110         int rc;
 111
 112         cb.data = data;
 113         cb.fn_known_sch = fn_known;
 114         cb.fn_unknown_sch = fn_unknown;
 115
 116         cb.set = idset_sch_new();
 117         if (!cb.set)
 118                 /* fall back to brute force scanning in case of oom */
 119                 return for_each_subchannel(call_fn_all_sch, &cb);
 120
 121         idset_fill(cb.set);
 122
 123         /* Process registered subchannels. */
 124         rc = bus_for_each_dev(&css_bus_type, NULL, &cb, call_fn_known_sch);
 125         if (rc)
 126                 goto out;
 127         /* Process unregistered subchannels. */
 128         if (fn_unknown)
 129                 rc = for_each_subchannel(call_fn_unknown_sch, &cb);
 130 out:
 131         idset_free(cb.set);
 132
 133         return rc;
 134 }
 135
 136 static void css_sch_todo(struct work_struct *work);
 137
 138 static struct subchannel *
 139 css_alloc_subchannel(struct subchannel_id schid)
 140 {
 141         struct subchannel *sch;
 142         int ret;
 143
 144         sch = kmalloc (sizeof (*sch), GFP_KERNEL | GFP_DMA);
 145         if (sch == NULL)
 146                 return ERR_PTR(-ENOMEM);
 147         ret = cio_validate_subchannel (sch, schid);
 148         if (ret < 0) {
 149                 kfree(sch);
 150                 return ERR_PTR(ret);
 151         }
 152         INIT_WORK(&sch->todo_work, css_sch_todo);
 153         return sch;
 154 }
 155
 156 static void
 157 css_subchannel_release(struct device *dev)
 158 {
 159         struct subchannel *sch;
 160
 161         sch = to_subchannel(dev);
 162         if (!cio_is_console(sch->schid)) {
 163                 /* Reset intparm to zeroes. */
 164                 sch->config.intparm = 0;
 165                 cio_commit_config(sch);
 166                 kfree(sch->lock);
 167                 kfree(sch);
 168         }
 169 }
 170
 171 static int css_sch_device_register(struct subchannel *sch)
 172 {
 173         int ret;
 174
 175         mutex_lock(&sch->reg_mutex);
 176         dev_set_name(&sch->dev, "0.%x.%04x", sch->schid.ssid,
 177                      sch->schid.sch_no);
 178         ret = device_register(&sch->dev);
 179         mutex_unlock(&sch->reg_mutex);
 180         return ret;
 181 }
 182
 183 /**
 184  * css_sch_device_unregister - unregister a subchannel
 185  * @sch: subchannel to be unregistered
 186  */
 187 void css_sch_device_unregister(struct subchannel *sch)
 188 {
 189         mutex_lock(&sch->reg_mutex);
 190         if (device_is_registered(&sch->dev))
 191                 device_unregister(&sch->dev);
 192         mutex_unlock(&sch->reg_mutex);
 193 }
 194 EXPORT_SYMBOL_GPL(css_sch_device_unregister);
 195
 196 static void css_sch_todo(struct work_struct *work)
 197 {
 198         struct subchannel *sch;
 199         enum sch_todo todo;
 200
 201         sch = container_of(work, struct subchannel, todo_work);
 202         /* Find out todo. */
 203         spin_lock_irq(sch->lock);
 204         todo = sch->todo;
 205         CIO_MSG_EVENT(4, "sch_todo: sch=0.%x.%04x, todo=%d\n", sch->schid.ssid,
 206                       sch->schid.sch_no, todo);
 207         sch->todo = SCH_TODO_NOTHING;
 208         spin_unlock_irq(sch->lock);
 209         /* Perform todo. */
 210         if (todo == SCH_TODO_UNREG)
 211                 css_sch_device_unregister(sch);
 212         /* Release workqueue ref. */
 213         put_device(&sch->dev);
 214 }
 215
 216 /**
 217  * css_sched_sch_todo - schedule a subchannel operation
 218  * @sch: subchannel
 219  * @todo: todo
 220  *
 221  * Schedule the operation identified by @todo to be performed on the slow path
 222  * workqueue. Do nothing if another operation with higher priority is already
 223  * scheduled. Needs to be called with subchannel lock held.
 224  */
 225 void css_sched_sch_todo(struct subchannel *sch, enum sch_todo todo)
 226 {
 227         CIO_MSG_EVENT(4, "sch_todo: sched sch=0.%x.%04x todo=%d\n",
 228                       sch->schid.ssid, sch->schid.sch_no, todo);
 229         if (sch->todo >= todo)
 230                 return;
 231         /* Get workqueue ref. */
 232         if (!get_device(&sch->dev))
 233                 return;
 234         sch->todo = todo;
 235         if (!queue_work(slow_path_wq, &sch->todo_work)) {
 236                 /* Already queued, release workqueue ref. */
 237                 put_device(&sch->dev);
 238         }
 239 }
 240
 241 static void ssd_from_pmcw(struct chsc_ssd_info *ssd, struct pmcw *pmcw)
 242 {
 243         int i;
 244         int mask;
 245
 246         memset(ssd, 0, sizeof(struct chsc_ssd_info));
 247         ssd->path_mask = pmcw->pim;
 248         for (i = 0; i < 8; i++) {
 249                 mask = 0x80 >> i;
 250                 if (pmcw->pim & mask) {
 251                         chp_id_init(&ssd->chpid[i]);
 252                         ssd->chpid[i].id = pmcw->chpid[i];
 253                 }
 254         }
 255 }
 256
 257 static void ssd_register_chpids(struct chsc_ssd_info *ssd)
 258 {
 259         int i;
 260         int mask;
 261
 262         for (i = 0; i < 8; i++) {
 263                 mask = 0x80 >> i;
 264                 if (ssd->path_mask & mask)
 265                         if (!chp_is_registered(ssd->chpid[i]))
 266                                 chp_new(ssd->chpid[i]);
 267         }
 268 }
 269
 270 void css_update_ssd_info(struct subchannel *sch)
 271 {
 272         int ret;
 273
 274         if (cio_is_console(sch->schid)) {
 275                 /* Console is initialized too early for functions requiring
 276                  * memory allocation. */
 277                 ssd_from_pmcw(&sch->ssd_info, &sch->schib.pmcw);
 278         } else {
 279                 ret = chsc_get_ssd_info(sch->schid, &sch->ssd_info);
 280                 if (ret)
 281                         ssd_from_pmcw(&sch->ssd_info, &sch->schib.pmcw);
 282                 ssd_register_chpids(&sch->ssd_info);
 283         }
 284 }
 285
 286 static ssize_t type_show(struct device *dev, struct device_attribute *attr,
 287                          char *buf)
 288 {
 289         struct subchannel *sch = to_subchannel(dev);
 290
 291         return sprintf(buf, "%01x\n", sch->st);
 292 }
 293
 294 static DEVICE_ATTR(type, 0444, type_show, NULL);
 295
 296 static ssize_t modalias_show(struct device *dev, struct device_attribute *attr,
 297                              char *buf)
 298 {
 299         struct subchannel *sch = to_subchannel(dev);
 300
 301         return sprintf(buf, "css:t%01X\n", sch->st);
 302 }
 303
 304 static DEVICE_ATTR(modalias, 0444, modalias_show, NULL);
 305
 306 static struct attribute *subch_attrs[] = {
 307         &dev_attr_type.attr,
 308         &dev_attr_modalias.attr,
 309         NULL,
 310 };
 311
 312 static struct attribute_group subch_attr_group = {
 313         .attrs = subch_attrs,
 314 };
 315
 316 static const struct attribute_group *default_subch_attr_groups[] = {
 317         &subch_attr_group,
 318         NULL,
 319 };
 320
 321 static int css_register_subchannel(struct subchannel *sch)
 322 {
 323         int ret;
 324
 325         /* Initialize the subchannel structure */
 326         sch->dev.parent = &channel_subsystems[0]->device;
 327         sch->dev.bus = &css_bus_type;
 328         sch->dev.release = &css_subchannel_release;
 329         sch->dev.groups = default_subch_attr_groups;
 330         /*
 331          * We don't want to generate uevents for I/O subchannels that don't
 332          * have a working ccw device behind them since they will be
 333          * unregistered before they can be used anyway, so we delay the add
 334          * uevent until after device recognition was successful.
 335          * Note that we suppress the uevent for all subchannel types;
 336          * the subchannel driver can decide itself when it wants to inform
 337          * userspace of its existence.
 338          */
 339         dev_set_uevent_suppress(&sch->dev, 1);
 340         css_update_ssd_info(sch);
 341         /* make it known to the system */
 342         ret = css_sch_device_register(sch);
 343         if (ret) {
 344                 CIO_MSG_EVENT(0, "Could not register sch 0.%x.%04x: %d\n",
 345                               sch->schid.ssid, sch->schid.sch_no, ret);
 346                 return ret;
 347         }
 348         if (!sch->driver) {
 349                 /*
 350                  * No driver matched. Generate the uevent now so that
 351                  * a fitting driver module may be loaded based on the
 352                  * modalias.
 353                  */
 354                 dev_set_uevent_suppress(&sch->dev, 0);
 355                 kobject_uevent(&sch->dev.kobj, KOBJ_ADD);
 356         }
 357         return ret;
 358 }
 359
 360 int css_probe_device(struct subchannel_id schid)
 361 {
 362         int ret;
 363         struct subchannel *sch;
 364
 365         if (cio_is_console(schid))
 366                 sch = cio_get_console_subchannel();
 367         else {
 368                 sch = css_alloc_subchannel(schid);
 369                 if (IS_ERR(sch))
 370                         return PTR_ERR(sch);
 371         }
 372         ret = css_register_subchannel(sch);
 373         if (ret) {
 374                 if (!cio_is_console(schid))
 375                         put_device(&sch->dev);
 376         }
 377         return ret;
 378 }
 379
 380 static int
 381 check_subchannel(struct device * dev, void * data)
 382 {
 383         struct subchannel *sch;
 384         struct subchannel_id *schid = data;
 385
 386         sch = to_subchannel(dev);
 387         return schid_equal(&sch->schid, schid);
 388 }
 389
 390 struct subchannel *
 391 get_subchannel_by_schid(struct subchannel_id schid)
 392 {
 393         struct device *dev;
 394
 395         dev = bus_find_device(&css_bus_type, NULL,
 396                               &schid, check_subchannel);
 397
 398         return dev ? to_subchannel(dev) : NULL;
 399 }
 400
 401 /**
 402  * css_sch_is_valid() - check if a subchannel is valid
 403  * @schib: subchannel information block for the subchannel
 404  */
 405 int css_sch_is_valid(struct schib *schib)
 406 {
 407         if ((schib->pmcw.st == SUBCHANNEL_TYPE_IO) && !schib->pmcw.dnv)
 408                 return 0;
 409         if ((schib->pmcw.st == SUBCHANNEL_TYPE_MSG) && !schib->pmcw.w)
 410                 return 0;
 411         return 1;
 412 }
 413 EXPORT_SYMBOL_GPL(css_sch_is_valid);
 414
 415 static int css_evaluate_new_subchannel(struct subchannel_id schid, int slow)
 416 {
 417         struct schib schib;
 418
 419         if (!slow) {
 420                 /* Will be done on the slow path. */
 421                 return -EAGAIN;
 422         }
 423         if (stsch_err(schid, &schib) || !css_sch_is_valid(&schib)) {
 424                 /* Unusable - ignore. */
 425                 return 0;
 426         }
 427         CIO_MSG_EVENT(4, "event: sch 0.%x.%04x, new\n", schid.ssid,
 428                       schid.sch_no);
 429
 430         return css_probe_device(schid);
 431 }
 432
 433 static int css_evaluate_known_subchannel(struct subchannel *sch, int slow)
 434 {
 435         int ret = 0;
 436
 437         if (sch->driver) {
 438                 if (sch->driver->sch_event)
 439                         ret = sch->driver->sch_event(sch, slow);
 440                 else
 441                         dev_dbg(&sch->dev,
 442                                 "Got subchannel machine check but "
 443                                 "no sch_event handler provided.\n");
 444         }
 445         if (ret != 0 && ret != -EAGAIN) {
 446                 CIO_MSG_EVENT(2, "eval: sch 0.%x.%04x, rc=%d\n",
 447                               sch->schid.ssid, sch->schid.sch_no, ret);
 448         }
 449         return ret;
 450 }
 451
 452 static void css_evaluate_subchannel(struct subchannel_id schid, int slow)
 453 {
 454         struct subchannel *sch;
 455         int ret;
 456
 457         sch = get_subchannel_by_schid(schid);
 458         if (sch) {
 459                 ret = css_evaluate_known_subchannel(sch, slow);
 460                 put_device(&sch->dev);
 461         } else
 462                 ret = css_evaluate_new_subchannel(schid, slow);
 463         if (ret == -EAGAIN)
 464                 css_schedule_eval(schid);
 465 }
 466
 467 static struct idset *slow_subchannel_set;
 468 static spinlock_t slow_subchannel_lock;
 469 static wait_queue_head_t css_eval_wq;
 470 static atomic_t css_eval_scheduled;
 471
 472 static int __init slow_subchannel_init(void)
 473 {
 474         spin_lock_init(&slow_subchannel_lock);
 475         atomic_set(&css_eval_scheduled, 0);
 476         init_waitqueue_head(&css_eval_wq);
 477         slow_subchannel_set = idset_sch_new();
 478         if (!slow_subchannel_set) {
 479                 CIO_MSG_EVENT(0, "could not allocate slow subchannel set\n");
 480                 return -ENOMEM;
 481         }
 482         return 0;
 483 }
 484
 485 static int slow_eval_known_fn(struct subchannel *sch, void *data)
 486 {
 487         int eval;
 488         int rc;
 489
 490         spin_lock_irq(&slow_subchannel_lock);
 491         eval = idset_sch_contains(slow_subchannel_set, sch->schid);
 492         idset_sch_del(slow_subchannel_set, sch->schid);
 493         spin_unlock_irq(&slow_subchannel_lock);
 494         if (eval) {
 495                 rc = css_evaluate_known_subchannel(sch, 1);
 496                 if (rc == -EAGAIN)
 497                         css_schedule_eval(sch->schid);
 498         }
 499         return 0;
 500 }
 501
 502 static int slow_eval_unknown_fn(struct subchannel_id schid, void *data)
 503 {
 504         int eval;
 505         int rc = 0;
 506
 507         spin_lock_irq(&slow_subchannel_lock);
 508         eval = idset_sch_contains(slow_subchannel_set, schid);
 509         idset_sch_del(slow_subchannel_set, schid);
 510         spin_unlock_irq(&slow_subchannel_lock);
 511         if (eval) {
 512                 rc = css_evaluate_new_subchannel(schid, 1);
 513                 switch (rc) {
 514                 case -EAGAIN:
 515                         css_schedule_eval(schid);
 516                         rc = 0;
 517                         break;
 518                 case -ENXIO:
 519                 case -ENOMEM:
 520                 case -EIO:
 521                         /* These should abort looping */
 522                         break;
 523                 default:
 524                         rc = 0;
 525                 }
 526         }
 527         return rc;
 528 }
 529
 530 static void css_slow_path_func(struct work_struct *unused)
 531 {
 532         unsigned long flags;
 533
 534         CIO_TRACE_EVENT(4, "slowpath");
 535         for_each_subchannel_staged(slow_eval_known_fn, slow_eval_unknown_fn,
 536                                    NULL);
 537         spin_lock_irqsave(&slow_subchannel_lock, flags);
 538         if (idset_is_empty(slow_subchannel_set)) {
 539                 atomic_set(&css_eval_scheduled, 0);
 540                 wake_up(&css_eval_wq);
 541         }
 542         spin_unlock_irqrestore(&slow_subchannel_lock, flags);
 543 }
 544
 545 static DECLARE_WORK(slow_path_work, css_slow_path_func);
 546 struct workqueue_struct *slow_path_wq;
 547
 548 void css_schedule_eval(struct subchannel_id schid)
 549 {
 550         unsigned long flags;
 551
 552         spin_lock_irqsave(&slow_subchannel_lock, flags);
 553         idset_sch_add(slow_subchannel_set, schid);
 554         atomic_set(&css_eval_scheduled, 1);
 555         queue_work(slow_path_wq, &slow_path_work);
 556         spin_unlock_irqrestore(&slow_subchannel_lock, flags);
 557 }
 558
 559 void css_schedule_eval_all(void)
 560 {
 561         unsigned long flags;
 562
 563         spin_lock_irqsave(&slow_subchannel_lock, flags);
 564         idset_fill(slow_subchannel_set);
 565         atomic_set(&css_eval_scheduled, 1);
 566         queue_work(slow_path_wq, &slow_path_work);
 567         spin_unlock_irqrestore(&slow_subchannel_lock, flags);
 568 }
 569
 570 static int __unset_registered(struct device *dev, void *data)
 571 {
 572         struct idset *set = data;
 573         struct subchannel *sch = to_subchannel(dev);
 574
 575         idset_sch_del(set, sch->schid);
 576         return 0;
 577 }
 578
 579 void css_schedule_eval_all_unreg(void)
 580 {
 581         unsigned long flags;
 582         struct idset *unreg_set;
 583
 584         /* Find unregistered subchannels. */
 585         unreg_set = idset_sch_new();
 586         if (!unreg_set) {
 587                 /* Fallback. */
 588                 css_schedule_eval_all();
 589                 return;
 590         }
 591         idset_fill(unreg_set);
 592         bus_for_each_dev(&css_bus_type, NULL, unreg_set, __unset_registered);
 593         /* Apply to slow_subchannel_set. */
 594         spin_lock_irqsave(&slow_subchannel_lock, flags);
 595         idset_add_set(slow_subchannel_set, unreg_set);
 596         atomic_set(&css_eval_scheduled, 1);
 597         queue_work(slow_path_wq, &slow_path_work);
 598         spin_unlock_irqrestore(&slow_subchannel_lock, flags);
 599         idset_free(unreg_set);
 600 }
 601
 602 void css_wait_for_slow_path(void)
 603 {
 604         flush_workqueue(slow_path_wq);
 605 }
 606
 607 /* Schedule reprobing of all unregistered subchannels. */
 608 void css_schedule_reprobe(void)
 609 {
 610         css_schedule_eval_all_unreg();
 611 }
 612 EXPORT_SYMBOL_GPL(css_schedule_reprobe);
 613
 614 /*
 615  * Called from the machine check handler for subchannel report words.
 616  */
 617 static void css_process_crw(struct crw *crw0, struct crw *crw1, int overflow)
 618 {
 619         struct subchannel_id mchk_schid;
 620
 621         if (overflow) {
 622                 css_schedule_eval_all();
 623                 return;
 624         }
 625         CIO_CRW_EVENT(2, "CRW0 reports slct=%d, oflw=%d, "
 626                       "chn=%d, rsc=%X, anc=%d, erc=%X, rsid=%X\n",
 627                       crw0->slct, crw0->oflw, crw0->chn, crw0->rsc, crw0->anc,
 628                       crw0->erc, crw0->rsid);
 629         if (crw1)
 630                 CIO_CRW_EVENT(2, "CRW1 reports slct=%d, oflw=%d, "
 631                               "chn=%d, rsc=%X, anc=%d, erc=%X, rsid=%X\n",
 632                               crw1->slct, crw1->oflw, crw1->chn, crw1->rsc,
 633                               crw1->anc, crw1->erc, crw1->rsid);
 634         init_subchannel_id(&mchk_schid);
 635         mchk_schid.sch_no = crw0->rsid;
 636         if (crw1)
 637                 mchk_schid.ssid = (crw1->rsid >> 8) & 3;
 638
 639         /*
 640          * Since we are always presented with IPI in the CRW, we have to
 641          * use stsch() to find out if the subchannel in question has come
 642          * or gone.
 643          */
 644         css_evaluate_subchannel(mchk_schid, 0);
 645 }
 646
 647 static void __init
 648 css_generate_pgid(struct channel_subsystem *css, u32 tod_high)
 649 {
 650         if (css_general_characteristics.mcss) {
 651                 css->global_pgid.pgid_high.ext_cssid.version = 0x80;
 652                 css->global_pgid.pgid_high.ext_cssid.cssid = css->cssid;
 653         } else {
 654 #ifdef CONFIG_SMP
 655                 css->global_pgid.pgid_high.cpu_addr = stap();
 656 #else
 657                 css->global_pgid.pgid_high.cpu_addr = 0;
 658 #endif
 659         }
 660         css->global_pgid.cpu_id = S390_lowcore.cpu_id.ident;
 661         css->global_pgid.cpu_model = S390_lowcore.cpu_id.machine;
 662         css->global_pgid.tod_high = tod_high;
 663
 664 }
 665
 666 static void
 667 channel_subsystem_release(struct device *dev)
 668 {
 669         struct channel_subsystem *css;
 670
 671         css = to_css(dev);
 672         mutex_destroy(&css->mutex);
 673         if (css->pseudo_subchannel) {
 674                 /* Implies that it has been generated but never registered. */
 675                 css_subchannel_release(&css->pseudo_subchannel->dev);
 676                 css->pseudo_subchannel = NULL;
 677         }
 678         kfree(css);
 679 }
 680
 681 static ssize_t
 682 css_cm_enable_show(struct device *dev, struct device_attribute *attr,
 683                    char *buf)
 684 {
 685         struct channel_subsystem *css = to_css(dev);
 686         int ret;
 687
 688         if (!css)
 689                 return 0;
 690         mutex_lock(&css->mutex);
 691         ret = sprintf(buf, "%x\n", css->cm_enabled);
 692         mutex_unlock(&css->mutex);
 693         return ret;
 694 }
 695
 696 static ssize_t
 697 css_cm_enable_store(struct device *dev, struct device_attribute *attr,
 698                     const char *buf, size_t count)
 699 {
 700         struct channel_subsystem *css = to_css(dev);
 701         int ret;
 702         unsigned long val;
 703
 704         ret = strict_strtoul(buf, 16, &val);
 705         if (ret)
 706                 return ret;
 707         mutex_lock(&css->mutex);
 708         switch (val) {
 709         case 0:
 710                 ret = css->cm_enabled ? chsc_secm(css, 0) : 0;
 711                 break;
 712         case 1:
 713                 ret = css->cm_enabled ? 0 : chsc_secm(css, 1);
 714                 break;
 715         default:
 716                 ret = -EINVAL;
 717         }
 718         mutex_unlock(&css->mutex);
 719         return ret < 0 ? ret : count;
 720 }
 721
 722 static DEVICE_ATTR(cm_enable, 0644, css_cm_enable_show, css_cm_enable_store);
 723
 724 static int __init setup_css(int nr)
 725 {
 726         u32 tod_high;
 727         int ret;
 728         struct channel_subsystem *css;
 729
 730         css = channel_subsystems[nr];
 731         memset(css, 0, sizeof(struct channel_subsystem));
 732         css->pseudo_subchannel =
 733                 kzalloc(sizeof(*css->pseudo_subchannel), GFP_KERNEL);
 734         if (!css->pseudo_subchannel)
 735                 return -ENOMEM;
 736         css->pseudo_subchannel->dev.parent = &css->device;
 737         css->pseudo_subchannel->dev.release = css_subchannel_release;
 738         dev_set_name(&css->pseudo_subchannel->dev, "defunct");
 739         mutex_init(&css->pseudo_subchannel->reg_mutex);
 740         ret = cio_create_sch_lock(css->pseudo_subchannel);
 741         if (ret) {
 742                 kfree(css->pseudo_subchannel);
 743                 return ret;
 744         }
 745         mutex_init(&css->mutex);
 746         css->valid = 1;
 747         css->cssid = nr;
 748         dev_set_name(&css->device, "css%x", nr);
 749         css->device.release = channel_subsystem_release;
 750         tod_high = (u32) (get_clock() >> 32);
 751         css_generate_pgid(css, tod_high);
 752         return 0;
 753 }
 754
 755 static int css_reboot_event(struct notifier_block *this,
 756                             unsigned long event,
 757                             void *ptr)
 758 {
 759         int ret, i;
 760
 761         ret = NOTIFY_DONE;
 762         for (i = 0; i <= __MAX_CSSID; i++) {
 763                 struct channel_subsystem *css;
 764
 765                 css = channel_subsystems[i];
 766                 mutex_lock(&css->mutex);
 767                 if (css->cm_enabled)
 768                         if (chsc_secm(css, 0))
 769                                 ret = NOTIFY_BAD;
 770                 mutex_unlock(&css->mutex);
 771         }
 772
 773         return ret;
 774 }
 775
 776 static struct notifier_block css_reboot_notifier = {
 777         .notifier_call = css_reboot_event,
 778 };
 779
 780 /*
 781  * Since the css devices are neither on a bus nor have a class
 782  * nor have a special device type, we cannot stop/restart channel
 783  * path measurements via the normal suspend/resume callbacks, but have
 784  * to use notifiers.
 785  */
 786 static int css_power_event(struct notifier_block *this, unsigned long event,
 787                            void *ptr)
 788 {
 789         void *secm_area;
 790         int ret, i;
 791
 792         switch (event) {
 793         case PM_HIBERNATION_PREPARE:
 794         case PM_SUSPEND_PREPARE:
 795                 ret = NOTIFY_DONE;
 796                 for (i = 0; i <= __MAX_CSSID; i++) {
 797                         struct channel_subsystem *css;
 798
 799                         css = channel_subsystems[i];
 800                         mutex_lock(&css->mutex);
 801                         if (!css->cm_enabled) {
 802                                 mutex_unlock(&css->mutex);
 803                                 continue;
 804                         }
 805                         secm_area = (void *)get_zeroed_page(GFP_KERNEL |
 806                                                             GFP_DMA);
 807                         if (secm_area) {
 808                                 if (__chsc_do_secm(css, 0, secm_area))
 809                                         ret = NOTIFY_BAD;
 810                                 free_page((unsigned long)secm_area);
 811                         } else
 812                                 ret = NOTIFY_BAD;
 813
 814                         mutex_unlock(&css->mutex);
 815                 }
 816                 break;
 817         case PM_POST_HIBERNATION:
 818         case PM_POST_SUSPEND:
 819                 ret = NOTIFY_DONE;
 820                 for (i = 0; i <= __MAX_CSSID; i++) {
 821                         struct channel_subsystem *css;
 822
 823                         css = channel_subsystems[i];
 824                         mutex_lock(&css->mutex);
 825                         if (!css->cm_enabled) {
 826                                 mutex_unlock(&css->mutex);
 827                                 continue;
 828                         }
 829                         secm_area = (void *)get_zeroed_page(GFP_KERNEL |
 830                                                             GFP_DMA);
 831                         if (secm_area) {
 832                                 if (__chsc_do_secm(css, 1, secm_area))
 833                                         ret = NOTIFY_BAD;
 834                                 free_page((unsigned long)secm_area);
 835                         } else
 836                                 ret = NOTIFY_BAD;
 837
 838                         mutex_unlock(&css->mutex);
 839                 }
 840                 /* search for subchannels, which appeared during hibernation */
 841                 css_schedule_reprobe();
 842                 break;
 843         default:
 844                 ret = NOTIFY_DONE;
 845         }
 846         return ret;
 847
 848 }
 849 static struct notifier_block css_power_notifier = {
 850         .notifier_call = css_power_event,
 851 };
 852
 853 /*
 854  * Now that the driver core is running, we can setup our channel subsystem.
 855  * The struct subchannel's are created during probing (except for the
 856  * static console subchannel).
 857  */
 858 static int __init css_bus_init(void)
 859 {
 860         int ret, i;
 861
 862         ret = chsc_determine_css_characteristics();
 863         if (ret == -ENOMEM)
 864                 goto out;
 865
 866         ret = chsc_alloc_sei_area();
 867         if (ret)
 868                 goto out;
 869
 870         /* Try to enable MSS. */
 871         ret = chsc_enable_facility(CHSC_SDA_OC_MSS);
 872         switch (ret) {
 873         case 0: /* Success. */
 874                 max_ssid = __MAX_SSID;
 875                 break;
 876         case -ENOMEM:
 877                 goto out;
 878         default:
 879                 max_ssid = 0;
 880         }
 881
 882         ret = slow_subchannel_init();
 883         if (ret)
 884                 goto out;
 885
 886         ret = crw_register_handler(CRW_RSC_SCH, css_process_crw);
 887         if (ret)
 888                 goto out;
 889
 890         if ((ret = bus_register(&css_bus_type)))
 891                 goto out;
 892
 893         /* Setup css structure. */
 894         for (i = 0; i <= __MAX_CSSID; i++) {
 895                 struct channel_subsystem *css;
 896
 897                 css = kmalloc(sizeof(struct channel_subsystem), GFP_KERNEL);
 898                 if (!css) {
 899                         ret = -ENOMEM;
 900                         goto out_unregister;
 901                 }
 902                 channel_subsystems[i] = css;
 903                 ret = setup_css(i);
 904                 if (ret) {
 905                         kfree(channel_subsystems[i]);
 906                         goto out_unregister;
 907                 }
 908                 ret = device_register(&css->device);
 909                 if (ret) {
 910                         put_device(&css->device);
 911                         goto out_unregister;
 912                 }
 913                 if (css_chsc_characteristics.secm) {
 914                         ret = device_create_file(&css->device,
 915                                                  &dev_attr_cm_enable);
 916                         if (ret)
 917                                 goto out_device;
 918                 }
 919                 ret = device_register(&css->pseudo_subchannel->dev);
 920                 if (ret) {
 921                         put_device(&css->pseudo_subchannel->dev);
 922                         goto out_file;
 923                 }
 924         }
 925         ret = register_reboot_notifier(&css_reboot_notifier);
 926         if (ret)
 927                 goto out_unregister;
 928         ret = register_pm_notifier(&css_power_notifier);
 929         if (ret) {
 930                 unregister_reboot_notifier(&css_reboot_notifier);
 931                 goto out_unregister;
 932         }
 933         css_init_done = 1;
 934
 935         /* Enable default isc for I/O subchannels. */
 936         isc_register(IO_SCH_ISC);
 937
 938         return 0;
 939 out_file:
 940         if (css_chsc_characteristics.secm)
 941                 device_remove_file(&channel_subsystems[i]->device,
 942                                    &dev_attr_cm_enable);
 943 out_device:
 944         device_unregister(&channel_subsystems[i]->device);
 945 out_unregister:
 946         while (i > 0) {
 947                 struct channel_subsystem *css;
 948
 949                 i--;
 950                 css = channel_subsystems[i];
 951                 device_unregister(&css->pseudo_subchannel->dev);
 952                 css->pseudo_subchannel = NULL;
 953                 if (css_chsc_characteristics.secm)
 954                         device_remove_file(&css->device,
 955                                            &dev_attr_cm_enable);
 956                 device_unregister(&css->device);
 957         }
 958         bus_unregister(&css_bus_type);
 959 out:
 960         crw_unregister_handler(CRW_RSC_CSS);
 961         chsc_free_sei_area();
 962         idset_free(slow_subchannel_set);
 963         pr_alert("The CSS device driver initialization failed with "
 964                  "errno=%d\n", ret);
 965         return ret;
 966 }
 967
 968 static void __init css_bus_cleanup(void)
 969 {
 970         struct channel_subsystem *css;
 971         int i;
 972
 973         for (i = 0; i <= __MAX_CSSID; i++) {
 974                 css = channel_subsystems[i];
 975                 device_unregister(&css->pseudo_subchannel->dev);
 976                 css->pseudo_subchannel = NULL;
 977                 if (css_chsc_characteristics.secm)
 978                         device_remove_file(&css->device, &dev_attr_cm_enable);
 979                 device_unregister(&css->device);
 980         }
 981         bus_unregister(&css_bus_type);
 982         crw_unregister_handler(CRW_RSC_CSS);
 983         chsc_free_sei_area();
 984         idset_free(slow_subchannel_set);
 985         isc_unregister(IO_SCH_ISC);
 986 }
 987
 988 static int __init channel_subsystem_init(void)
 989 {
 990         int ret;
 991
 992         ret = css_bus_init();
 993         if (ret)
 994                 return ret;
 995
 996         ret = io_subchannel_init();
 997         if (ret)
 998                 css_bus_cleanup();
 999
1000         return ret;
1001 }
1002 subsys_initcall(channel_subsystem_init);
1003
1004 static int css_settle(struct device_driver *drv, void *unused)
1005 {
1006         struct css_driver *cssdrv = to_cssdriver(drv);
1007
1008         if (cssdrv->settle)
1009                 cssdrv->settle();
1010         return 0;
1011 }
1012
1013 /*
1014  * Wait for the initialization of devices to finish, to make sure we are
1015  * done with our setup if the search for the root device starts.
1016  */
1017 static int __init channel_subsystem_init_sync(void)
1018 {
1019         /* Start initial subchannel evaluation. */
1020         css_schedule_eval_all();
1021         /* Wait for the evaluation of subchannels to finish. */
1022         wait_event(css_eval_wq, atomic_read(&css_eval_scheduled) == 0);
1023         /* Wait for the subchannel type specific initialization to finish */
1024         return bus_for_each_drv(&css_bus_type, NULL, NULL, css_settle);
1025 }
1026 subsys_initcall_sync(channel_subsystem_init_sync);
1027
1028 int sch_is_pseudo_sch(struct subchannel *sch)
1029 {
1030         return sch == to_css(sch->dev.parent)->pseudo_subchannel;
1031 }
1032
1033 static int css_bus_match(struct device *dev, struct device_driver *drv)
1034 {
1035         struct subchannel *sch = to_subchannel(dev);
1036         struct css_driver *driver = to_cssdriver(drv);
1037         struct css_device_id *id;
1038
1039         for (id = driver->subchannel_type; id->match_flags; id++) {
1040                 if (sch->st == id->type)
1041                         return 1;
1042         }
1043
1044         return 0;
1045 }
1046
1047 static int css_probe(struct device *dev)
1048 {
1049         struct subchannel *sch;
1050         int ret;
1051
1052         sch = to_subchannel(dev);
1053         sch->driver = to_cssdriver(dev->driver);
1054         ret = sch->driver->probe ? sch->driver->probe(sch) : 0;
1055         if (ret)
1056                 sch->driver = NULL;
1057         return ret;
1058 }
1059
1060 static int css_remove(struct device *dev)
1061 {
1062         struct subchannel *sch;
1063         int ret;
1064
1065         sch = to_subchannel(dev);
1066         ret = sch->driver->remove ? sch->driver->remove(sch) : 0;
1067         sch->driver = NULL;
1068         return ret;
1069 }
1070
1071 static void css_shutdown(struct device *dev)
1072 {
1073         struct subchannel *sch;
1074
1075         sch = to_subchannel(dev);
1076         if (sch->driver && sch->driver->shutdown)
1077                 sch->driver->shutdown(sch);
1078 }
1079
1080 static int css_uevent(struct device *dev, struct kobj_uevent_env *env)
1081 {
1082         struct subchannel *sch = to_subchannel(dev);
1083         int ret;
1084
1085         ret = add_uevent_var(env, "ST=%01X", sch->st);
1086         if (ret)
1087                 return ret;
1088         ret = add_uevent_var(env, "MODALIAS=css:t%01X", sch->st);
1089         return ret;
1090 }
1091
1092 static int css_pm_prepare(struct device *dev)
1093 {
1094         struct subchannel *sch = to_subchannel(dev);
1095         struct css_driver *drv;
1096
1097         if (mutex_is_locked(&sch->reg_mutex))
1098                 return -EAGAIN;
1099         if (!sch->dev.driver)
1100                 return 0;
1101         drv = to_cssdriver(sch->dev.driver);
1102         /* Notify drivers that they may not register children. */
1103         return drv->prepare ? drv->prepare(sch) : 0;
1104 }
1105
1106 static void css_pm_complete(struct device *dev)
1107 {
1108         struct subchannel *sch = to_subchannel(dev);
1109         struct css_driver *drv;
1110
1111         if (!sch->dev.driver)
1112                 return;
1113         drv = to_cssdriver(sch->dev.driver);
1114         if (drv->complete)
1115                 drv->complete(sch);
1116 }
1117
1118 static int css_pm_freeze(struct device *dev)
1119 {
1120         struct subchannel *sch = to_subchannel(dev);
1121         struct css_driver *drv;
1122
1123         if (!sch->dev.driver)
1124                 return 0;
1125         drv = to_cssdriver(sch->dev.driver);
1126         return drv->freeze ? drv->freeze(sch) : 0;
1127 }
1128
1129 static int css_pm_thaw(struct device *dev)
1130 {
1131         struct subchannel *sch = to_subchannel(dev);
1132         struct css_driver *drv;
1133
1134         if (!sch->dev.driver)
1135                 return 0;
1136         drv = to_cssdriver(sch->dev.driver);
1137         return drv->thaw ? drv->thaw(sch) : 0;
1138 }
1139
1140 static int css_pm_restore(struct device *dev)
1141 {
1142         struct subchannel *sch = to_subchannel(dev);
1143         struct css_driver *drv;
1144
1145         if (!sch->dev.driver)
1146                 return 0;
1147         drv = to_cssdriver(sch->dev.driver);
1148         return drv->restore ? drv->restore(sch) : 0;
1149 }
1150
1151 static const struct dev_pm_ops css_pm_ops = {
1152         .prepare = css_pm_prepare,
1153         .complete = css_pm_complete,
1154         .freeze = css_pm_freeze,
1155         .thaw = css_pm_thaw,
1156         .restore = css_pm_restore,
1157 };
1158
1159 struct bus_type css_bus_type = {
1160         .name     = "css",
1161         .match    = css_bus_match,
1162         .probe    = css_probe,
1163         .remove   = css_remove,
1164         .shutdown = css_shutdown,
1165         .uevent   = css_uevent,
1166         .pm = &css_pm_ops,
1167 };
1168
1169 /**
1170  * css_driver_register - register a css driver
1171  * @cdrv: css driver to register
1172  *
1173  * This is mainly a wrapper around driver_register that sets name
1174  * and bus_type in the embedded struct device_driver correctly.
1175  */
1176 int css_driver_register(struct css_driver *cdrv)
1177 {
1178         cdrv->drv.name = cdrv->name;
1179         cdrv->drv.bus = &css_bus_type;
1180         cdrv->drv.owner = cdrv->owner;
1181         return driver_register(&cdrv->drv);
1182 }
1183 EXPORT_SYMBOL_GPL(css_driver_register);
1184
1185 /**
1186  * css_driver_unregister - unregister a css driver
1187  * @cdrv: css driver to unregister
1188  *
1189  * This is a wrapper around driver_unregister.
1190  */
1191 void css_driver_unregister(struct css_driver *cdrv)
1192 {
1193         driver_unregister(&cdrv->drv);
1194 }
1195 EXPORT_SYMBOL_GPL(css_driver_unregister);
1196
1197 MODULE_LICENSE("GPL");
1198 EXPORT_SYMBOL(css_bus_type);