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 static int need_reprobe = 0;
  35 static int max_ssid = 0;
  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 struct subchannel *
 138 css_alloc_subchannel(struct subchannel_id schid)
 139 {
 140         struct subchannel *sch;
 141         int ret;
 142
 143         sch = kmalloc (sizeof (*sch), GFP_KERNEL | GFP_DMA);
 144         if (sch == NULL)
 145                 return ERR_PTR(-ENOMEM);
 146         ret = cio_validate_subchannel (sch, schid);
 147         if (ret < 0) {
 148                 kfree(sch);
 149                 return ERR_PTR(ret);
 150         }
 151         return sch;
 152 }
 153
 154 static void
 155 css_subchannel_release(struct device *dev)
 156 {
 157         struct subchannel *sch;
 158
 159         sch = to_subchannel(dev);
 160         if (!cio_is_console(sch->schid)) {
 161                 /* Reset intparm to zeroes. */
 162                 sch->config.intparm = 0;
 163                 cio_commit_config(sch);
 164                 kfree(sch->lock);
 165                 kfree(sch);
 166         }
 167 }
 168
 169 static int css_sch_device_register(struct subchannel *sch)
 170 {
 171         int ret;
 172
 173         mutex_lock(&sch->reg_mutex);
 174         dev_set_name(&sch->dev, "0.%x.%04x", sch->schid.ssid,
 175                      sch->schid.sch_no);
 176         ret = device_register(&sch->dev);
 177         mutex_unlock(&sch->reg_mutex);
 178         return ret;
 179 }
 180
 181 /**
 182  * css_sch_device_unregister - unregister a subchannel
 183  * @sch: subchannel to be unregistered
 184  */
 185 void css_sch_device_unregister(struct subchannel *sch)
 186 {
 187         mutex_lock(&sch->reg_mutex);
 188         if (device_is_registered(&sch->dev))
 189                 device_unregister(&sch->dev);
 190         mutex_unlock(&sch->reg_mutex);
 191 }
 192 EXPORT_SYMBOL_GPL(css_sch_device_unregister);
 193
 194 static void ssd_from_pmcw(struct chsc_ssd_info *ssd, struct pmcw *pmcw)
 195 {
 196         int i;
 197         int mask;
 198
 199         memset(ssd, 0, sizeof(struct chsc_ssd_info));
 200         ssd->path_mask = pmcw->pim;
 201         for (i = 0; i < 8; i++) {
 202                 mask = 0x80 >> i;
 203                 if (pmcw->pim & mask) {
 204                         chp_id_init(&ssd->chpid[i]);
 205                         ssd->chpid[i].id = pmcw->chpid[i];
 206                 }
 207         }
 208 }
 209
 210 static void ssd_register_chpids(struct chsc_ssd_info *ssd)
 211 {
 212         int i;
 213         int mask;
 214
 215         for (i = 0; i < 8; i++) {
 216                 mask = 0x80 >> i;
 217                 if (ssd->path_mask & mask)
 218                         if (!chp_is_registered(ssd->chpid[i]))
 219                                 chp_new(ssd->chpid[i]);
 220         }
 221 }
 222
 223 void css_update_ssd_info(struct subchannel *sch)
 224 {
 225         int ret;
 226
 227         if (cio_is_console(sch->schid)) {
 228                 /* Console is initialized too early for functions requiring
 229                  * memory allocation. */
 230                 ssd_from_pmcw(&sch->ssd_info, &sch->schib.pmcw);
 231         } else {
 232                 ret = chsc_get_ssd_info(sch->schid, &sch->ssd_info);
 233                 if (ret)
 234                         ssd_from_pmcw(&sch->ssd_info, &sch->schib.pmcw);
 235                 ssd_register_chpids(&sch->ssd_info);
 236         }
 237 }
 238
 239 static ssize_t type_show(struct device *dev, struct device_attribute *attr,
 240                          char *buf)
 241 {
 242         struct subchannel *sch = to_subchannel(dev);
 243
 244         return sprintf(buf, "%01x\n", sch->st);
 245 }
 246
 247 static DEVICE_ATTR(type, 0444, type_show, NULL);
 248
 249 static ssize_t modalias_show(struct device *dev, struct device_attribute *attr,
 250                              char *buf)
 251 {
 252         struct subchannel *sch = to_subchannel(dev);
 253
 254         return sprintf(buf, "css:t%01X\n", sch->st);
 255 }
 256
 257 static DEVICE_ATTR(modalias, 0444, modalias_show, NULL);
 258
 259 static struct attribute *subch_attrs[] = {
 260         &dev_attr_type.attr,
 261         &dev_attr_modalias.attr,
 262         NULL,
 263 };
 264
 265 static struct attribute_group subch_attr_group = {
 266         .attrs = subch_attrs,
 267 };
 268
 269 static const struct attribute_group *default_subch_attr_groups[] = {
 270         &subch_attr_group,
 271         NULL,
 272 };
 273
 274 static int css_register_subchannel(struct subchannel *sch)
 275 {
 276         int ret;
 277
 278         /* Initialize the subchannel structure */
 279         sch->dev.parent = &channel_subsystems[0]->device;
 280         sch->dev.bus = &css_bus_type;
 281         sch->dev.release = &css_subchannel_release;
 282         sch->dev.groups = default_subch_attr_groups;
 283         /*
 284          * We don't want to generate uevents for I/O subchannels that don't
 285          * have a working ccw device behind them since they will be
 286          * unregistered before they can be used anyway, so we delay the add
 287          * uevent until after device recognition was successful.
 288          * Note that we suppress the uevent for all subchannel types;
 289          * the subchannel driver can decide itself when it wants to inform
 290          * userspace of its existence.
 291          */
 292         dev_set_uevent_suppress(&sch->dev, 1);
 293         css_update_ssd_info(sch);
 294         /* make it known to the system */
 295         ret = css_sch_device_register(sch);
 296         if (ret) {
 297                 CIO_MSG_EVENT(0, "Could not register sch 0.%x.%04x: %d\n",
 298                               sch->schid.ssid, sch->schid.sch_no, ret);
 299                 return ret;
 300         }
 301         if (!sch->driver) {
 302                 /*
 303                  * No driver matched. Generate the uevent now so that
 304                  * a fitting driver module may be loaded based on the
 305                  * modalias.
 306                  */
 307                 dev_set_uevent_suppress(&sch->dev, 0);
 308                 kobject_uevent(&sch->dev.kobj, KOBJ_ADD);
 309         }
 310         return ret;
 311 }
 312
 313 int css_probe_device(struct subchannel_id schid)
 314 {
 315         int ret;
 316         struct subchannel *sch;
 317
 318         sch = css_alloc_subchannel(schid);
 319         if (IS_ERR(sch))
 320                 return PTR_ERR(sch);
 321         ret = css_register_subchannel(sch);
 322         if (ret)
 323                 put_device(&sch->dev);
 324         return ret;
 325 }
 326
 327 static int
 328 check_subchannel(struct device * dev, void * data)
 329 {
 330         struct subchannel *sch;
 331         struct subchannel_id *schid = data;
 332
 333         sch = to_subchannel(dev);
 334         return schid_equal(&sch->schid, schid);
 335 }
 336
 337 struct subchannel *
 338 get_subchannel_by_schid(struct subchannel_id schid)
 339 {
 340         struct device *dev;
 341
 342         dev = bus_find_device(&css_bus_type, NULL,
 343                               &schid, check_subchannel);
 344
 345         return dev ? to_subchannel(dev) : NULL;
 346 }
 347
 348 /**
 349  * css_sch_is_valid() - check if a subchannel is valid
 350  * @schib: subchannel information block for the subchannel
 351  */
 352 int css_sch_is_valid(struct schib *schib)
 353 {
 354         if ((schib->pmcw.st == SUBCHANNEL_TYPE_IO) && !schib->pmcw.dnv)
 355                 return 0;
 356         if ((schib->pmcw.st == SUBCHANNEL_TYPE_MSG) && !schib->pmcw.w)
 357                 return 0;
 358         return 1;
 359 }
 360 EXPORT_SYMBOL_GPL(css_sch_is_valid);
 361
 362 static int css_evaluate_new_subchannel(struct subchannel_id schid, int slow)
 363 {
 364         struct schib schib;
 365
 366         if (!slow) {
 367                 /* Will be done on the slow path. */
 368                 return -EAGAIN;
 369         }
 370         if (stsch_err(schid, &schib) || !css_sch_is_valid(&schib)) {
 371                 /* Unusable - ignore. */
 372                 return 0;
 373         }
 374         CIO_MSG_EVENT(4, "Evaluating schid 0.%x.%04x, event %d, unknown, "
 375                          "slow path.\n", schid.ssid, schid.sch_no, CIO_OPER);
 376
 377         return css_probe_device(schid);
 378 }
 379
 380 static int css_evaluate_known_subchannel(struct subchannel *sch, int slow)
 381 {
 382         int ret = 0;
 383
 384         if (sch->driver) {
 385                 if (sch->driver->sch_event)
 386                         ret = sch->driver->sch_event(sch, slow);
 387                 else
 388                         dev_dbg(&sch->dev,
 389                                 "Got subchannel machine check but "
 390                                 "no sch_event handler provided.\n");
 391         }
 392         return ret;
 393 }
 394
 395 static void css_evaluate_subchannel(struct subchannel_id schid, int slow)
 396 {
 397         struct subchannel *sch;
 398         int ret;
 399
 400         sch = get_subchannel_by_schid(schid);
 401         if (sch) {
 402                 ret = css_evaluate_known_subchannel(sch, slow);
 403                 put_device(&sch->dev);
 404         } else
 405                 ret = css_evaluate_new_subchannel(schid, slow);
 406         if (ret == -EAGAIN)
 407                 css_schedule_eval(schid);
 408 }
 409
 410 static struct idset *slow_subchannel_set;
 411 static spinlock_t slow_subchannel_lock;
 412 static wait_queue_head_t css_eval_wq;
 413 static atomic_t css_eval_scheduled;
 414
 415 static int __init slow_subchannel_init(void)
 416 {
 417         spin_lock_init(&slow_subchannel_lock);
 418         atomic_set(&css_eval_scheduled, 0);
 419         init_waitqueue_head(&css_eval_wq);
 420         slow_subchannel_set = idset_sch_new();
 421         if (!slow_subchannel_set) {
 422                 CIO_MSG_EVENT(0, "could not allocate slow subchannel set\n");
 423                 return -ENOMEM;
 424         }
 425         return 0;
 426 }
 427
 428 static int slow_eval_known_fn(struct subchannel *sch, void *data)
 429 {
 430         int eval;
 431         int rc;
 432
 433         spin_lock_irq(&slow_subchannel_lock);
 434         eval = idset_sch_contains(slow_subchannel_set, sch->schid);
 435         idset_sch_del(slow_subchannel_set, sch->schid);
 436         spin_unlock_irq(&slow_subchannel_lock);
 437         if (eval) {
 438                 rc = css_evaluate_known_subchannel(sch, 1);
 439                 if (rc == -EAGAIN)
 440                         css_schedule_eval(sch->schid);
 441         }
 442         return 0;
 443 }
 444
 445 static int slow_eval_unknown_fn(struct subchannel_id schid, void *data)
 446 {
 447         int eval;
 448         int rc = 0;
 449
 450         spin_lock_irq(&slow_subchannel_lock);
 451         eval = idset_sch_contains(slow_subchannel_set, schid);
 452         idset_sch_del(slow_subchannel_set, schid);
 453         spin_unlock_irq(&slow_subchannel_lock);
 454         if (eval) {
 455                 rc = css_evaluate_new_subchannel(schid, 1);
 456                 switch (rc) {
 457                 case -EAGAIN:
 458                         css_schedule_eval(schid);
 459                         rc = 0;
 460                         break;
 461                 case -ENXIO:
 462                 case -ENOMEM:
 463                 case -EIO:
 464                         /* These should abort looping */
 465                         break;
 466                 default:
 467                         rc = 0;
 468                 }
 469         }
 470         return rc;
 471 }
 472
 473 static void css_slow_path_func(struct work_struct *unused)
 474 {
 475         unsigned long flags;
 476
 477         CIO_TRACE_EVENT(4, "slowpath");
 478         for_each_subchannel_staged(slow_eval_known_fn, slow_eval_unknown_fn,
 479                                    NULL);
 480         spin_lock_irqsave(&slow_subchannel_lock, flags);
 481         if (idset_is_empty(slow_subchannel_set)) {
 482                 atomic_set(&css_eval_scheduled, 0);
 483                 wake_up(&css_eval_wq);
 484         }
 485         spin_unlock_irqrestore(&slow_subchannel_lock, flags);
 486 }
 487
 488 static DECLARE_WORK(slow_path_work, css_slow_path_func);
 489 struct workqueue_struct *slow_path_wq;
 490
 491 void css_schedule_eval(struct subchannel_id schid)
 492 {
 493         unsigned long flags;
 494
 495         spin_lock_irqsave(&slow_subchannel_lock, flags);
 496         idset_sch_add(slow_subchannel_set, schid);
 497         atomic_set(&css_eval_scheduled, 1);
 498         queue_work(slow_path_wq, &slow_path_work);
 499         spin_unlock_irqrestore(&slow_subchannel_lock, flags);
 500 }
 501
 502 void css_schedule_eval_all(void)
 503 {
 504         unsigned long flags;
 505
 506         spin_lock_irqsave(&slow_subchannel_lock, flags);
 507         idset_fill(slow_subchannel_set);
 508         atomic_set(&css_eval_scheduled, 1);
 509         queue_work(slow_path_wq, &slow_path_work);
 510         spin_unlock_irqrestore(&slow_subchannel_lock, flags);
 511 }
 512
 513 void css_wait_for_slow_path(void)
 514 {
 515         flush_workqueue(slow_path_wq);
 516 }
 517
 518 /* Reprobe subchannel if unregistered. */
 519 static int reprobe_subchannel(struct subchannel_id schid, void *data)
 520 {
 521         int ret;
 522
 523         CIO_MSG_EVENT(6, "cio: reprobe 0.%x.%04x\n",
 524                       schid.ssid, schid.sch_no);
 525         if (need_reprobe)
 526                 return -EAGAIN;
 527
 528         ret = css_probe_device(schid);
 529         switch (ret) {
 530         case 0:
 531                 break;
 532         case -ENXIO:
 533         case -ENOMEM:
 534         case -EIO:
 535                 /* These should abort looping */
 536                 break;
 537         default:
 538                 ret = 0;
 539         }
 540
 541         return ret;
 542 }
 543
 544 static void reprobe_after_idle(struct work_struct *unused)
 545 {
 546         /* Make sure initial subchannel scan is done. */
 547         wait_event(ccw_device_init_wq,
 548                    atomic_read(&ccw_device_init_count) == 0);
 549         if (need_reprobe)
 550                 css_schedule_reprobe();
 551 }
 552
 553 static DECLARE_WORK(reprobe_idle_work, reprobe_after_idle);
 554
 555 /* Work function used to reprobe all unregistered subchannels. */
 556 static void reprobe_all(struct work_struct *unused)
 557 {
 558         int ret;
 559
 560         CIO_MSG_EVENT(4, "reprobe start\n");
 561
 562         /* Make sure initial subchannel scan is done. */
 563         if (atomic_read(&ccw_device_init_count) != 0) {
 564                 queue_work(ccw_device_work, &reprobe_idle_work);
 565                 return;
 566         }
 567         need_reprobe = 0;
 568         ret = for_each_subchannel_staged(NULL, reprobe_subchannel, NULL);
 569
 570         CIO_MSG_EVENT(4, "reprobe done (rc=%d, need_reprobe=%d)\n", ret,
 571                       need_reprobe);
 572 }
 573
 574 static DECLARE_WORK(css_reprobe_work, reprobe_all);
 575
 576 /* Schedule reprobing of all unregistered subchannels. */
 577 void css_schedule_reprobe(void)
 578 {
 579         need_reprobe = 1;
 580         queue_work(slow_path_wq, &css_reprobe_work);
 581 }
 582
 583 EXPORT_SYMBOL_GPL(css_schedule_reprobe);
 584
 585 /*
 586  * Called from the machine check handler for subchannel report words.
 587  */
 588 static void css_process_crw(struct crw *crw0, struct crw *crw1, int overflow)
 589 {
 590         struct subchannel_id mchk_schid;
 591
 592         if (overflow) {
 593                 css_schedule_eval_all();
 594                 return;
 595         }
 596         CIO_CRW_EVENT(2, "CRW0 reports slct=%d, oflw=%d, "
 597                       "chn=%d, rsc=%X, anc=%d, erc=%X, rsid=%X\n",
 598                       crw0->slct, crw0->oflw, crw0->chn, crw0->rsc, crw0->anc,
 599                       crw0->erc, crw0->rsid);
 600         if (crw1)
 601                 CIO_CRW_EVENT(2, "CRW1 reports slct=%d, oflw=%d, "
 602                               "chn=%d, rsc=%X, anc=%d, erc=%X, rsid=%X\n",
 603                               crw1->slct, crw1->oflw, crw1->chn, crw1->rsc,
 604                               crw1->anc, crw1->erc, crw1->rsid);
 605         init_subchannel_id(&mchk_schid);
 606         mchk_schid.sch_no = crw0->rsid;
 607         if (crw1)
 608                 mchk_schid.ssid = (crw1->rsid >> 8) & 3;
 609
 610         /*
 611          * Since we are always presented with IPI in the CRW, we have to
 612          * use stsch() to find out if the subchannel in question has come
 613          * or gone.
 614          */
 615         css_evaluate_subchannel(mchk_schid, 0);
 616 }
 617
 618 static int __init setup_subchannel(struct subchannel_id schid, void *data)
 619 {
 620         struct subchannel *sch;
 621         int ret;
 622
 623         if (cio_is_console(schid))
 624                 sch = cio_get_console_subchannel();
 625         else {
 626                 sch = css_alloc_subchannel(schid);
 627                 if (IS_ERR(sch))
 628                         ret = PTR_ERR(sch);
 629                 else
 630                         ret = 0;
 631                 switch (ret) {
 632                 case 0:
 633                         break;
 634                 case -ENOMEM:
 635                         panic("Out of memory in init_channel_subsystem\n");
 636                 /* -ENXIO: no more subchannels. */
 637                 case -ENXIO:
 638                         return ret;
 639                 /* -EIO: this subchannel set not supported. */
 640                 case -EIO:
 641                         return ret;
 642                 default:
 643                         return 0;
 644                 }
 645         }
 646         /*
 647          * We register ALL valid subchannels in ioinfo, even those
 648          * that have been present before init_channel_subsystem.
 649          * These subchannels can't have been registered yet (kmalloc
 650          * not working) so we do it now. This is true e.g. for the
 651          * console subchannel.
 652          */
 653         if (css_register_subchannel(sch)) {
 654                 if (!cio_is_console(schid))
 655                         put_device(&sch->dev);
 656         }
 657         return 0;
 658 }
 659
 660 static void __init
 661 css_generate_pgid(struct channel_subsystem *css, u32 tod_high)
 662 {
 663         if (css_general_characteristics.mcss) {
 664                 css->global_pgid.pgid_high.ext_cssid.version = 0x80;
 665                 css->global_pgid.pgid_high.ext_cssid.cssid = css->cssid;
 666         } else {
 667 #ifdef CONFIG_SMP
 668                 css->global_pgid.pgid_high.cpu_addr = stap();
 669 #else
 670                 css->global_pgid.pgid_high.cpu_addr = 0;
 671 #endif
 672         }
 673         css->global_pgid.cpu_id = S390_lowcore.cpu_id.ident;
 674         css->global_pgid.cpu_model = S390_lowcore.cpu_id.machine;
 675         css->global_pgid.tod_high = tod_high;
 676
 677 }
 678
 679 static void
 680 channel_subsystem_release(struct device *dev)
 681 {
 682         struct channel_subsystem *css;
 683
 684         css = to_css(dev);
 685         mutex_destroy(&css->mutex);
 686         if (css->pseudo_subchannel) {
 687                 /* Implies that it has been generated but never registered. */
 688                 css_subchannel_release(&css->pseudo_subchannel->dev);
 689                 css->pseudo_subchannel = NULL;
 690         }
 691         kfree(css);
 692 }
 693
 694 static ssize_t
 695 css_cm_enable_show(struct device *dev, struct device_attribute *attr,
 696                    char *buf)
 697 {
 698         struct channel_subsystem *css = to_css(dev);
 699         int ret;
 700
 701         if (!css)
 702                 return 0;
 703         mutex_lock(&css->mutex);
 704         ret = sprintf(buf, "%x\n", css->cm_enabled);
 705         mutex_unlock(&css->mutex);
 706         return ret;
 707 }
 708
 709 static ssize_t
 710 css_cm_enable_store(struct device *dev, struct device_attribute *attr,
 711                     const char *buf, size_t count)
 712 {
 713         struct channel_subsystem *css = to_css(dev);
 714         int ret;
 715         unsigned long val;
 716
 717         ret = strict_strtoul(buf, 16, &val);
 718         if (ret)
 719                 return ret;
 720         mutex_lock(&css->mutex);
 721         switch (val) {
 722         case 0:
 723                 ret = css->cm_enabled ? chsc_secm(css, 0) : 0;
 724                 break;
 725         case 1:
 726                 ret = css->cm_enabled ? 0 : chsc_secm(css, 1);
 727                 break;
 728         default:
 729                 ret = -EINVAL;
 730         }
 731         mutex_unlock(&css->mutex);
 732         return ret < 0 ? ret : count;
 733 }
 734
 735 static DEVICE_ATTR(cm_enable, 0644, css_cm_enable_show, css_cm_enable_store);
 736
 737 static int __init setup_css(int nr)
 738 {
 739         u32 tod_high;
 740         int ret;
 741         struct channel_subsystem *css;
 742
 743         css = channel_subsystems[nr];
 744         memset(css, 0, sizeof(struct channel_subsystem));
 745         css->pseudo_subchannel =
 746                 kzalloc(sizeof(*css->pseudo_subchannel), GFP_KERNEL);
 747         if (!css->pseudo_subchannel)
 748                 return -ENOMEM;
 749         css->pseudo_subchannel->dev.parent = &css->device;
 750         css->pseudo_subchannel->dev.release = css_subchannel_release;
 751         dev_set_name(&css->pseudo_subchannel->dev, "defunct");
 752         ret = cio_create_sch_lock(css->pseudo_subchannel);
 753         if (ret) {
 754                 kfree(css->pseudo_subchannel);
 755                 return ret;
 756         }
 757         mutex_init(&css->mutex);
 758         css->valid = 1;
 759         css->cssid = nr;
 760         dev_set_name(&css->device, "css%x", nr);
 761         css->device.release = channel_subsystem_release;
 762         tod_high = (u32) (get_clock() >> 32);
 763         css_generate_pgid(css, tod_high);
 764         return 0;
 765 }
 766
 767 static int css_reboot_event(struct notifier_block *this,
 768                             unsigned long event,
 769                             void *ptr)
 770 {
 771         int ret, i;
 772
 773         ret = NOTIFY_DONE;
 774         for (i = 0; i <= __MAX_CSSID; i++) {
 775                 struct channel_subsystem *css;
 776
 777                 css = channel_subsystems[i];
 778                 mutex_lock(&css->mutex);
 779                 if (css->cm_enabled)
 780                         if (chsc_secm(css, 0))
 781                                 ret = NOTIFY_BAD;
 782                 mutex_unlock(&css->mutex);
 783         }
 784
 785         return ret;
 786 }
 787
 788 static struct notifier_block css_reboot_notifier = {
 789         .notifier_call = css_reboot_event,
 790 };
 791
 792 /*
 793  * Since the css devices are neither on a bus nor have a class
 794  * nor have a special device type, we cannot stop/restart channel
 795  * path measurements via the normal suspend/resume callbacks, but have
 796  * to use notifiers.
 797  */
 798 static int css_power_event(struct notifier_block *this, unsigned long event,
 799                            void *ptr)
 800 {
 801         void *secm_area;
 802         int ret, i;
 803
 804         switch (event) {
 805         case PM_HIBERNATION_PREPARE:
 806         case PM_SUSPEND_PREPARE:
 807                 ret = NOTIFY_DONE;
 808                 for (i = 0; i <= __MAX_CSSID; i++) {
 809                         struct channel_subsystem *css;
 810
 811                         css = channel_subsystems[i];
 812                         mutex_lock(&css->mutex);
 813                         if (!css->cm_enabled) {
 814                                 mutex_unlock(&css->mutex);
 815                                 continue;
 816                         }
 817                         secm_area = (void *)get_zeroed_page(GFP_KERNEL |
 818                                                             GFP_DMA);
 819                         if (secm_area) {
 820                                 if (__chsc_do_secm(css, 0, secm_area))
 821                                         ret = NOTIFY_BAD;
 822                                 free_page((unsigned long)secm_area);
 823                         } else
 824                                 ret = NOTIFY_BAD;
 825
 826                         mutex_unlock(&css->mutex);
 827                 }
 828                 break;
 829         case PM_POST_HIBERNATION:
 830         case PM_POST_SUSPEND:
 831                 ret = NOTIFY_DONE;
 832                 for (i = 0; i <= __MAX_CSSID; i++) {
 833                         struct channel_subsystem *css;
 834
 835                         css = channel_subsystems[i];
 836                         mutex_lock(&css->mutex);
 837                         if (!css->cm_enabled) {
 838                                 mutex_unlock(&css->mutex);
 839                                 continue;
 840                         }
 841                         secm_area = (void *)get_zeroed_page(GFP_KERNEL |
 842                                                             GFP_DMA);
 843                         if (secm_area) {
 844                                 if (__chsc_do_secm(css, 1, secm_area))
 845                                         ret = NOTIFY_BAD;
 846                                 free_page((unsigned long)secm_area);
 847                         } else
 848                                 ret = NOTIFY_BAD;
 849
 850                         mutex_unlock(&css->mutex);
 851                 }
 852                 /* search for subchannels, which appeared during hibernation */
 853                 css_schedule_reprobe();
 854                 break;
 855         default:
 856                 ret = NOTIFY_DONE;
 857         }
 858         return ret;
 859
 860 }
 861 static struct notifier_block css_power_notifier = {
 862         .notifier_call = css_power_event,
 863 };
 864
 865 /*
 866  * Now that the driver core is running, we can setup our channel subsystem.
 867  * The struct subchannel's are created during probing (except for the
 868  * static console subchannel).
 869  */
 870 static int __init css_bus_init(void)
 871 {
 872         int ret, i;
 873
 874         ret = chsc_determine_css_characteristics();
 875         if (ret == -ENOMEM)
 876                 goto out;
 877
 878         ret = chsc_alloc_sei_area();
 879         if (ret)
 880                 goto out;
 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         /* Try to enable MSS. */
 894         ret = chsc_enable_facility(CHSC_SDA_OC_MSS);
 895         switch (ret) {
 896         case 0: /* Success. */
 897                 max_ssid = __MAX_SSID;
 898                 break;
 899         case -ENOMEM:
 900                 goto out_bus;
 901         default:
 902                 max_ssid = 0;
 903         }
 904         /* Setup css structure. */
 905         for (i = 0; i <= __MAX_CSSID; i++) {
 906                 struct channel_subsystem *css;
 907
 908                 css = kmalloc(sizeof(struct channel_subsystem), GFP_KERNEL);
 909                 if (!css) {
 910                         ret = -ENOMEM;
 911                         goto out_unregister;
 912                 }
 913                 channel_subsystems[i] = css;
 914                 ret = setup_css(i);
 915                 if (ret) {
 916                         kfree(channel_subsystems[i]);
 917                         goto out_unregister;
 918                 }
 919                 ret = device_register(&css->device);
 920                 if (ret) {
 921                         put_device(&css->device);
 922                         goto out_unregister;
 923                 }
 924                 if (css_chsc_characteristics.secm) {
 925                         ret = device_create_file(&css->device,
 926                                                  &dev_attr_cm_enable);
 927                         if (ret)
 928                                 goto out_device;
 929                 }
 930                 ret = device_register(&css->pseudo_subchannel->dev);
 931                 if (ret) {
 932                         put_device(&css->pseudo_subchannel->dev);
 933                         goto out_file;
 934                 }
 935         }
 936         ret = register_reboot_notifier(&css_reboot_notifier);
 937         if (ret)
 938                 goto out_unregister;
 939         ret = register_pm_notifier(&css_power_notifier);
 940         if (ret) {
 941                 unregister_reboot_notifier(&css_reboot_notifier);
 942                 goto out_unregister;
 943         }
 944         css_init_done = 1;
 945
 946         /* Enable default isc for I/O subchannels. */
 947         isc_register(IO_SCH_ISC);
 948
 949         return 0;
 950 out_file:
 951         if (css_chsc_characteristics.secm)
 952                 device_remove_file(&channel_subsystems[i]->device,
 953                                    &dev_attr_cm_enable);
 954 out_device:
 955         device_unregister(&channel_subsystems[i]->device);
 956 out_unregister:
 957         while (i > 0) {
 958                 struct channel_subsystem *css;
 959
 960                 i--;
 961                 css = channel_subsystems[i];
 962                 device_unregister(&css->pseudo_subchannel->dev);
 963                 css->pseudo_subchannel = NULL;
 964                 if (css_chsc_characteristics.secm)
 965                         device_remove_file(&css->device,
 966                                            &dev_attr_cm_enable);
 967                 device_unregister(&css->device);
 968         }
 969 out_bus:
 970         bus_unregister(&css_bus_type);
 971 out:
 972         crw_unregister_handler(CRW_RSC_CSS);
 973         chsc_free_sei_area();
 974         kfree(slow_subchannel_set);
 975         pr_alert("The CSS device driver initialization failed with "
 976                  "errno=%d\n", ret);
 977         return ret;
 978 }
 979
 980 static void __init css_bus_cleanup(void)
 981 {
 982         struct channel_subsystem *css;
 983         int i;
 984
 985         for (i = 0; i <= __MAX_CSSID; i++) {
 986                 css = channel_subsystems[i];
 987                 device_unregister(&css->pseudo_subchannel->dev);
 988                 css->pseudo_subchannel = NULL;
 989                 if (css_chsc_characteristics.secm)
 990                         device_remove_file(&css->device, &dev_attr_cm_enable);
 991                 device_unregister(&css->device);
 992         }
 993         bus_unregister(&css_bus_type);
 994         crw_unregister_handler(CRW_RSC_CSS);
 995         chsc_free_sei_area();
 996         kfree(slow_subchannel_set);
 997         isc_unregister(IO_SCH_ISC);
 998 }
 999
1000 static int __init channel_subsystem_init(void)
1001 {
1002         int ret;
1003
1004         ret = css_bus_init();
1005         if (ret)
1006                 return ret;
1007
1008         ret = io_subchannel_init();
1009         if (ret)
1010                 css_bus_cleanup();
1011
1012         return ret;
1013 }
1014 subsys_initcall(channel_subsystem_init);
1015
1016 /*
1017  * Wait for the initialization of devices to finish, to make sure we are
1018  * done with our setup if the search for the root device starts.
1019  */
1020 static int __init channel_subsystem_init_sync(void)
1021 {
1022         /* Allocate and register subchannels. */
1023         for_each_subchannel(setup_subchannel, NULL);
1024         /* Wait for the evaluation of subchannels to finish. */
1025         wait_event(css_eval_wq, atomic_read(&css_eval_scheduled) == 0);
1026
1027         /* Wait for the initialization of ccw devices to finish. */
1028         wait_event(ccw_device_init_wq,
1029                    atomic_read(&ccw_device_init_count) == 0);
1030         flush_workqueue(ccw_device_work);
1031
1032         return 0;
1033 }
1034 subsys_initcall_sync(channel_subsystem_init_sync);
1035
1036 int sch_is_pseudo_sch(struct subchannel *sch)
1037 {
1038         return sch == to_css(sch->dev.parent)->pseudo_subchannel;
1039 }
1040
1041 static int css_bus_match(struct device *dev, struct device_driver *drv)
1042 {
1043         struct subchannel *sch = to_subchannel(dev);
1044         struct css_driver *driver = to_cssdriver(drv);
1045         struct css_device_id *id;
1046
1047         for (id = driver->subchannel_type; id->match_flags; id++) {
1048                 if (sch->st == id->type)
1049                         return 1;
1050         }
1051
1052         return 0;
1053 }
1054
1055 static int css_probe(struct device *dev)
1056 {
1057         struct subchannel *sch;
1058         int ret;
1059
1060         sch = to_subchannel(dev);
1061         sch->driver = to_cssdriver(dev->driver);
1062         ret = sch->driver->probe ? sch->driver->probe(sch) : 0;
1063         if (ret)
1064                 sch->driver = NULL;
1065         return ret;
1066 }
1067
1068 static int css_remove(struct device *dev)
1069 {
1070         struct subchannel *sch;
1071         int ret;
1072
1073         sch = to_subchannel(dev);
1074         ret = sch->driver->remove ? sch->driver->remove(sch) : 0;
1075         sch->driver = NULL;
1076         return ret;
1077 }
1078
1079 static void css_shutdown(struct device *dev)
1080 {
1081         struct subchannel *sch;
1082
1083         sch = to_subchannel(dev);
1084         if (sch->driver && sch->driver->shutdown)
1085                 sch->driver->shutdown(sch);
1086 }
1087
1088 static int css_uevent(struct device *dev, struct kobj_uevent_env *env)
1089 {
1090         struct subchannel *sch = to_subchannel(dev);
1091         int ret;
1092
1093         ret = add_uevent_var(env, "ST=%01X", sch->st);
1094         if (ret)
1095                 return ret;
1096         ret = add_uevent_var(env, "MODALIAS=css:t%01X", sch->st);
1097         return ret;
1098 }
1099
1100 static int css_pm_prepare(struct device *dev)
1101 {
1102         struct subchannel *sch = to_subchannel(dev);
1103         struct css_driver *drv;
1104
1105         if (mutex_is_locked(&sch->reg_mutex))
1106                 return -EAGAIN;
1107         if (!sch->dev.driver)
1108                 return 0;
1109         drv = to_cssdriver(sch->dev.driver);
1110         /* Notify drivers that they may not register children. */
1111         return drv->prepare ? drv->prepare(sch) : 0;
1112 }
1113
1114 static void css_pm_complete(struct device *dev)
1115 {
1116         struct subchannel *sch = to_subchannel(dev);
1117         struct css_driver *drv;
1118
1119         if (!sch->dev.driver)
1120                 return;
1121         drv = to_cssdriver(sch->dev.driver);
1122         if (drv->complete)
1123                 drv->complete(sch);
1124 }
1125
1126 static int css_pm_freeze(struct device *dev)
1127 {
1128         struct subchannel *sch = to_subchannel(dev);
1129         struct css_driver *drv;
1130
1131         if (!sch->dev.driver)
1132                 return 0;
1133         drv = to_cssdriver(sch->dev.driver);
1134         return drv->freeze ? drv->freeze(sch) : 0;
1135 }
1136
1137 static int css_pm_thaw(struct device *dev)
1138 {
1139         struct subchannel *sch = to_subchannel(dev);
1140         struct css_driver *drv;
1141
1142         if (!sch->dev.driver)
1143                 return 0;
1144         drv = to_cssdriver(sch->dev.driver);
1145         return drv->thaw ? drv->thaw(sch) : 0;
1146 }
1147
1148 static int css_pm_restore(struct device *dev)
1149 {
1150         struct subchannel *sch = to_subchannel(dev);
1151         struct css_driver *drv;
1152
1153         if (!sch->dev.driver)
1154                 return 0;
1155         drv = to_cssdriver(sch->dev.driver);
1156         return drv->restore ? drv->restore(sch) : 0;
1157 }
1158
1159 static struct dev_pm_ops css_pm_ops = {
1160         .prepare = css_pm_prepare,
1161         .complete = css_pm_complete,
1162         .freeze = css_pm_freeze,
1163         .thaw = css_pm_thaw,
1164         .restore = css_pm_restore,
1165 };
1166
1167 struct bus_type css_bus_type = {
1168         .name     = "css",
1169         .match    = css_bus_match,
1170         .probe    = css_probe,
1171         .remove   = css_remove,
1172         .shutdown = css_shutdown,
1173         .uevent   = css_uevent,
1174         .pm = &css_pm_ops,
1175 };
1176
1177 /**
1178  * css_driver_register - register a css driver
1179  * @cdrv: css driver to register
1180  *
1181  * This is mainly a wrapper around driver_register that sets name
1182  * and bus_type in the embedded struct device_driver correctly.
1183  */
1184 int css_driver_register(struct css_driver *cdrv)
1185 {
1186         cdrv->drv.name = cdrv->name;
1187         cdrv->drv.bus = &css_bus_type;
1188         cdrv->drv.owner = cdrv->owner;
1189         return driver_register(&cdrv->drv);
1190 }
1191 EXPORT_SYMBOL_GPL(css_driver_register);
1192
1193 /**
1194  * css_driver_unregister - unregister a css driver
1195  * @cdrv: css driver to unregister
1196  *
1197  * This is a wrapper around driver_unregister.
1198  */
1199 void css_driver_unregister(struct css_driver *cdrv)
1200 {
1201         driver_unregister(&cdrv->drv);
1202 }
1203 EXPORT_SYMBOL_GPL(css_driver_unregister);
1204
1205 MODULE_LICENSE("GPL");
1206 EXPORT_SYMBOL(css_bus_type);