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 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
 413 static int __init slow_subchannel_init(void)
 414 {
 415         spin_lock_init(&slow_subchannel_lock);
 416         slow_subchannel_set = idset_sch_new();
 417         if (!slow_subchannel_set) {
 418                 CIO_MSG_EVENT(0, "could not allocate slow subchannel set\n");
 419                 return -ENOMEM;
 420         }
 421         return 0;
 422 }
 423
 424 static int slow_eval_known_fn(struct subchannel *sch, void *data)
 425 {
 426         int eval;
 427         int rc;
 428
 429         spin_lock_irq(&slow_subchannel_lock);
 430         eval = idset_sch_contains(slow_subchannel_set, sch->schid);
 431         idset_sch_del(slow_subchannel_set, sch->schid);
 432         spin_unlock_irq(&slow_subchannel_lock);
 433         if (eval) {
 434                 rc = css_evaluate_known_subchannel(sch, 1);
 435                 if (rc == -EAGAIN)
 436                         css_schedule_eval(sch->schid);
 437         }
 438         return 0;
 439 }
 440
 441 static int slow_eval_unknown_fn(struct subchannel_id schid, void *data)
 442 {
 443         int eval;
 444         int rc = 0;
 445
 446         spin_lock_irq(&slow_subchannel_lock);
 447         eval = idset_sch_contains(slow_subchannel_set, schid);
 448         idset_sch_del(slow_subchannel_set, schid);
 449         spin_unlock_irq(&slow_subchannel_lock);
 450         if (eval) {
 451                 rc = css_evaluate_new_subchannel(schid, 1);
 452                 switch (rc) {
 453                 case -EAGAIN:
 454                         css_schedule_eval(schid);
 455                         rc = 0;
 456                         break;
 457                 case -ENXIO:
 458                 case -ENOMEM:
 459                 case -EIO:
 460                         /* These should abort looping */
 461                         break;
 462                 default:
 463                         rc = 0;
 464                 }
 465         }
 466         return rc;
 467 }
 468
 469 static void css_slow_path_func(struct work_struct *unused)
 470 {
 471         CIO_TRACE_EVENT(4, "slowpath");
 472         for_each_subchannel_staged(slow_eval_known_fn, slow_eval_unknown_fn,
 473                                    NULL);
 474 }
 475
 476 static DECLARE_WORK(slow_path_work, css_slow_path_func);
 477 struct workqueue_struct *slow_path_wq;
 478
 479 void css_schedule_eval(struct subchannel_id schid)
 480 {
 481         unsigned long flags;
 482
 483         spin_lock_irqsave(&slow_subchannel_lock, flags);
 484         idset_sch_add(slow_subchannel_set, schid);
 485         queue_work(slow_path_wq, &slow_path_work);
 486         spin_unlock_irqrestore(&slow_subchannel_lock, flags);
 487 }
 488
 489 void css_schedule_eval_all(void)
 490 {
 491         unsigned long flags;
 492
 493         spin_lock_irqsave(&slow_subchannel_lock, flags);
 494         idset_fill(slow_subchannel_set);
 495         queue_work(slow_path_wq, &slow_path_work);
 496         spin_unlock_irqrestore(&slow_subchannel_lock, flags);
 497 }
 498
 499 void css_wait_for_slow_path(void)
 500 {
 501         flush_workqueue(slow_path_wq);
 502 }
 503
 504 /* Reprobe subchannel if unregistered. */
 505 static int reprobe_subchannel(struct subchannel_id schid, void *data)
 506 {
 507         int ret;
 508
 509         CIO_MSG_EVENT(6, "cio: reprobe 0.%x.%04x\n",
 510                       schid.ssid, schid.sch_no);
 511         if (need_reprobe)
 512                 return -EAGAIN;
 513
 514         ret = css_probe_device(schid);
 515         switch (ret) {
 516         case 0:
 517                 break;
 518         case -ENXIO:
 519         case -ENOMEM:
 520         case -EIO:
 521                 /* These should abort looping */
 522                 break;
 523         default:
 524                 ret = 0;
 525         }
 526
 527         return ret;
 528 }
 529
 530 static void reprobe_after_idle(struct work_struct *unused)
 531 {
 532         /* Make sure initial subchannel scan is done. */
 533         wait_event(ccw_device_init_wq,
 534                    atomic_read(&ccw_device_init_count) == 0);
 535         if (need_reprobe)
 536                 css_schedule_reprobe();
 537 }
 538
 539 static DECLARE_WORK(reprobe_idle_work, reprobe_after_idle);
 540
 541 /* Work function used to reprobe all unregistered subchannels. */
 542 static void reprobe_all(struct work_struct *unused)
 543 {
 544         int ret;
 545
 546         CIO_MSG_EVENT(4, "reprobe start\n");
 547
 548         /* Make sure initial subchannel scan is done. */
 549         if (atomic_read(&ccw_device_init_count) != 0) {
 550                 queue_work(ccw_device_work, &reprobe_idle_work);
 551                 return;
 552         }
 553         need_reprobe = 0;
 554         ret = for_each_subchannel_staged(NULL, reprobe_subchannel, NULL);
 555
 556         CIO_MSG_EVENT(4, "reprobe done (rc=%d, need_reprobe=%d)\n", ret,
 557                       need_reprobe);
 558 }
 559
 560 static DECLARE_WORK(css_reprobe_work, reprobe_all);
 561
 562 /* Schedule reprobing of all unregistered subchannels. */
 563 void css_schedule_reprobe(void)
 564 {
 565         need_reprobe = 1;
 566         queue_work(slow_path_wq, &css_reprobe_work);
 567 }
 568
 569 EXPORT_SYMBOL_GPL(css_schedule_reprobe);
 570
 571 /*
 572  * Called from the machine check handler for subchannel report words.
 573  */
 574 static void css_process_crw(struct crw *crw0, struct crw *crw1, int overflow)
 575 {
 576         struct subchannel_id mchk_schid;
 577
 578         if (overflow) {
 579                 css_schedule_eval_all();
 580                 return;
 581         }
 582         CIO_CRW_EVENT(2, "CRW0 reports slct=%d, oflw=%d, "
 583                       "chn=%d, rsc=%X, anc=%d, erc=%X, rsid=%X\n",
 584                       crw0->slct, crw0->oflw, crw0->chn, crw0->rsc, crw0->anc,
 585                       crw0->erc, crw0->rsid);
 586         if (crw1)
 587                 CIO_CRW_EVENT(2, "CRW1 reports slct=%d, oflw=%d, "
 588                               "chn=%d, rsc=%X, anc=%d, erc=%X, rsid=%X\n",
 589                               crw1->slct, crw1->oflw, crw1->chn, crw1->rsc,
 590                               crw1->anc, crw1->erc, crw1->rsid);
 591         init_subchannel_id(&mchk_schid);
 592         mchk_schid.sch_no = crw0->rsid;
 593         if (crw1)
 594                 mchk_schid.ssid = (crw1->rsid >> 8) & 3;
 595
 596         /*
 597          * Since we are always presented with IPI in the CRW, we have to
 598          * use stsch() to find out if the subchannel in question has come
 599          * or gone.
 600          */
 601         css_evaluate_subchannel(mchk_schid, 0);
 602 }
 603
 604 static int __init
 605 __init_channel_subsystem(struct subchannel_id schid, void *data)
 606 {
 607         struct subchannel *sch;
 608         int ret;
 609
 610         if (cio_is_console(schid))
 611                 sch = cio_get_console_subchannel();
 612         else {
 613                 sch = css_alloc_subchannel(schid);
 614                 if (IS_ERR(sch))
 615                         ret = PTR_ERR(sch);
 616                 else
 617                         ret = 0;
 618                 switch (ret) {
 619                 case 0:
 620                         break;
 621                 case -ENOMEM:
 622                         panic("Out of memory in init_channel_subsystem\n");
 623                 /* -ENXIO: no more subchannels. */
 624                 case -ENXIO:
 625                         return ret;
 626                 /* -EIO: this subchannel set not supported. */
 627                 case -EIO:
 628                         return ret;
 629                 default:
 630                         return 0;
 631                 }
 632         }
 633         /*
 634          * We register ALL valid subchannels in ioinfo, even those
 635          * that have been present before init_channel_subsystem.
 636          * These subchannels can't have been registered yet (kmalloc
 637          * not working) so we do it now. This is true e.g. for the
 638          * console subchannel.
 639          */
 640         if (css_register_subchannel(sch)) {
 641                 if (!cio_is_console(schid))
 642                         put_device(&sch->dev);
 643         }
 644         return 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         ret = cio_create_sch_lock(css->pseudo_subchannel);
 740         if (ret) {
 741                 kfree(css->pseudo_subchannel);
 742                 return ret;
 743         }
 744         mutex_init(&css->mutex);
 745         css->valid = 1;
 746         css->cssid = nr;
 747         dev_set_name(&css->device, "css%x", nr);
 748         css->device.release = channel_subsystem_release;
 749         tod_high = (u32) (get_clock() >> 32);
 750         css_generate_pgid(css, tod_high);
 751         return 0;
 752 }
 753
 754 static int css_reboot_event(struct notifier_block *this,
 755                             unsigned long event,
 756                             void *ptr)
 757 {
 758         int ret, i;
 759
 760         ret = NOTIFY_DONE;
 761         for (i = 0; i <= __MAX_CSSID; i++) {
 762                 struct channel_subsystem *css;
 763
 764                 css = channel_subsystems[i];
 765                 mutex_lock(&css->mutex);
 766                 if (css->cm_enabled)
 767                         if (chsc_secm(css, 0))
 768                                 ret = NOTIFY_BAD;
 769                 mutex_unlock(&css->mutex);
 770         }
 771
 772         return ret;
 773 }
 774
 775 static struct notifier_block css_reboot_notifier = {
 776         .notifier_call = css_reboot_event,
 777 };
 778
 779 /*
 780  * Since the css devices are neither on a bus nor have a class
 781  * nor have a special device type, we cannot stop/restart channel
 782  * path measurements via the normal suspend/resume callbacks, but have
 783  * to use notifiers.
 784  */
 785 static int css_power_event(struct notifier_block *this, unsigned long event,
 786                            void *ptr)
 787 {
 788         void *secm_area;
 789         int ret, i;
 790
 791         switch (event) {
 792         case PM_HIBERNATION_PREPARE:
 793         case PM_SUSPEND_PREPARE:
 794                 ret = NOTIFY_DONE;
 795                 for (i = 0; i <= __MAX_CSSID; i++) {
 796                         struct channel_subsystem *css;
 797
 798                         css = channel_subsystems[i];
 799                         mutex_lock(&css->mutex);
 800                         if (!css->cm_enabled) {
 801                                 mutex_unlock(&css->mutex);
 802                                 continue;
 803                         }
 804                         secm_area = (void *)get_zeroed_page(GFP_KERNEL |
 805                                                             GFP_DMA);
 806                         if (secm_area) {
 807                                 if (__chsc_do_secm(css, 0, secm_area))
 808                                         ret = NOTIFY_BAD;
 809                                 free_page((unsigned long)secm_area);
 810                         } else
 811                                 ret = NOTIFY_BAD;
 812
 813                         mutex_unlock(&css->mutex);
 814                 }
 815                 break;
 816         case PM_POST_HIBERNATION:
 817         case PM_POST_SUSPEND:
 818                 ret = NOTIFY_DONE;
 819                 for (i = 0; i <= __MAX_CSSID; i++) {
 820                         struct channel_subsystem *css;
 821
 822                         css = channel_subsystems[i];
 823                         mutex_lock(&css->mutex);
 824                         if (!css->cm_enabled) {
 825                                 mutex_unlock(&css->mutex);
 826                                 continue;
 827                         }
 828                         secm_area = (void *)get_zeroed_page(GFP_KERNEL |
 829                                                             GFP_DMA);
 830                         if (secm_area) {
 831                                 if (__chsc_do_secm(css, 1, secm_area))
 832                                         ret = NOTIFY_BAD;
 833                                 free_page((unsigned long)secm_area);
 834                         } else
 835                                 ret = NOTIFY_BAD;
 836
 837                         mutex_unlock(&css->mutex);
 838                 }
 839                 /* search for subchannels, which appeared during hibernation */
 840                 css_schedule_reprobe();
 841                 break;
 842         default:
 843                 ret = NOTIFY_DONE;
 844         }
 845         return ret;
 846
 847 }
 848 static struct notifier_block css_power_notifier = {
 849         .notifier_call = css_power_event,
 850 };
 851
 852 /*
 853  * Now that the driver core is running, we can setup our channel subsystem.
 854  * The struct subchannel's are created during probing (except for the
 855  * static console subchannel).
 856  */
 857 static int __init
 858 init_channel_subsystem (void)
 859 {
 860         int ret, i;
 861
 862         ret = chsc_determine_css_characteristics();
 863         if (ret == -ENOMEM)
 864                 goto out; /* No need to continue. */
 865
 866         ret = chsc_alloc_sei_area();
 867         if (ret)
 868                 goto out;
 869
 870         ret = slow_subchannel_init();
 871         if (ret)
 872                 goto out;
 873
 874         ret = crw_register_handler(CRW_RSC_SCH, css_process_crw);
 875         if (ret)
 876                 goto out;
 877
 878         if ((ret = bus_register(&css_bus_type)))
 879                 goto out;
 880
 881         /* Try to enable MSS. */
 882         ret = chsc_enable_facility(CHSC_SDA_OC_MSS);
 883         switch (ret) {
 884         case 0: /* Success. */
 885                 max_ssid = __MAX_SSID;
 886                 break;
 887         case -ENOMEM:
 888                 goto out_bus;
 889         default:
 890                 max_ssid = 0;
 891         }
 892         /* Setup css structure. */
 893         for (i = 0; i <= __MAX_CSSID; i++) {
 894                 struct channel_subsystem *css;
 895
 896                 css = kmalloc(sizeof(struct channel_subsystem), GFP_KERNEL);
 897                 if (!css) {
 898                         ret = -ENOMEM;
 899                         goto out_unregister;
 900                 }
 901                 channel_subsystems[i] = css;
 902                 ret = setup_css(i);
 903                 if (ret) {
 904                         kfree(channel_subsystems[i]);
 905                         goto out_unregister;
 906                 }
 907                 ret = device_register(&css->device);
 908                 if (ret) {
 909                         put_device(&css->device);
 910                         goto out_unregister;
 911                 }
 912                 if (css_chsc_characteristics.secm) {
 913                         ret = device_create_file(&css->device,
 914                                                  &dev_attr_cm_enable);
 915                         if (ret)
 916                                 goto out_device;
 917                 }
 918                 ret = device_register(&css->pseudo_subchannel->dev);
 919                 if (ret) {
 920                         put_device(&css->pseudo_subchannel->dev);
 921                         goto out_file;
 922                 }
 923         }
 924         ret = register_reboot_notifier(&css_reboot_notifier);
 925         if (ret)
 926                 goto out_unregister;
 927         ret = register_pm_notifier(&css_power_notifier);
 928         if (ret) {
 929                 unregister_reboot_notifier(&css_reboot_notifier);
 930                 goto out_unregister;
 931         }
 932         css_init_done = 1;
 933
 934         /* Enable default isc for I/O subchannels. */
 935         isc_register(IO_SCH_ISC);
 936
 937         for_each_subchannel(__init_channel_subsystem, NULL);
 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 out_bus:
 959         bus_unregister(&css_bus_type);
 960 out:
 961         crw_unregister_handler(CRW_RSC_CSS);
 962         chsc_free_sei_area();
 963         kfree(slow_subchannel_set);
 964         pr_alert("The CSS device driver initialization failed with "
 965                  "errno=%d\n", ret);
 966         return ret;
 967 }
 968
 969 int sch_is_pseudo_sch(struct subchannel *sch)
 970 {
 971         return sch == to_css(sch->dev.parent)->pseudo_subchannel;
 972 }
 973
 974 static int css_bus_match(struct device *dev, struct device_driver *drv)
 975 {
 976         struct subchannel *sch = to_subchannel(dev);
 977         struct css_driver *driver = to_cssdriver(drv);
 978         struct css_device_id *id;
 979
 980         for (id = driver->subchannel_type; id->match_flags; id++) {
 981                 if (sch->st == id->type)
 982                         return 1;
 983         }
 984
 985         return 0;
 986 }
 987
 988 static int css_probe(struct device *dev)
 989 {
 990         struct subchannel *sch;
 991         int ret;
 992
 993         sch = to_subchannel(dev);
 994         sch->driver = to_cssdriver(dev->driver);
 995         ret = sch->driver->probe ? sch->driver->probe(sch) : 0;
 996         if (ret)
 997                 sch->driver = NULL;
 998         return ret;
 999 }
1000
1001 static int css_remove(struct device *dev)
1002 {
1003         struct subchannel *sch;
1004         int ret;
1005
1006         sch = to_subchannel(dev);
1007         ret = sch->driver->remove ? sch->driver->remove(sch) : 0;
1008         sch->driver = NULL;
1009         return ret;
1010 }
1011
1012 static void css_shutdown(struct device *dev)
1013 {
1014         struct subchannel *sch;
1015
1016         sch = to_subchannel(dev);
1017         if (sch->driver && sch->driver->shutdown)
1018                 sch->driver->shutdown(sch);
1019 }
1020
1021 static int css_uevent(struct device *dev, struct kobj_uevent_env *env)
1022 {
1023         struct subchannel *sch = to_subchannel(dev);
1024         int ret;
1025
1026         ret = add_uevent_var(env, "ST=%01X", sch->st);
1027         if (ret)
1028                 return ret;
1029         ret = add_uevent_var(env, "MODALIAS=css:t%01X", sch->st);
1030         return ret;
1031 }
1032
1033 static int css_pm_prepare(struct device *dev)
1034 {
1035         struct subchannel *sch = to_subchannel(dev);
1036         struct css_driver *drv;
1037
1038         if (mutex_is_locked(&sch->reg_mutex))
1039                 return -EAGAIN;
1040         if (!sch->dev.driver)
1041                 return 0;
1042         drv = to_cssdriver(sch->dev.driver);
1043         /* Notify drivers that they may not register children. */
1044         return drv->prepare ? drv->prepare(sch) : 0;
1045 }
1046
1047 static void css_pm_complete(struct device *dev)
1048 {
1049         struct subchannel *sch = to_subchannel(dev);
1050         struct css_driver *drv;
1051
1052         if (!sch->dev.driver)
1053                 return;
1054         drv = to_cssdriver(sch->dev.driver);
1055         if (drv->complete)
1056                 drv->complete(sch);
1057 }
1058
1059 static int css_pm_freeze(struct device *dev)
1060 {
1061         struct subchannel *sch = to_subchannel(dev);
1062         struct css_driver *drv;
1063
1064         if (!sch->dev.driver)
1065                 return 0;
1066         drv = to_cssdriver(sch->dev.driver);
1067         return drv->freeze ? drv->freeze(sch) : 0;
1068 }
1069
1070 static int css_pm_thaw(struct device *dev)
1071 {
1072         struct subchannel *sch = to_subchannel(dev);
1073         struct css_driver *drv;
1074
1075         if (!sch->dev.driver)
1076                 return 0;
1077         drv = to_cssdriver(sch->dev.driver);
1078         return drv->thaw ? drv->thaw(sch) : 0;
1079 }
1080
1081 static int css_pm_restore(struct device *dev)
1082 {
1083         struct subchannel *sch = to_subchannel(dev);
1084         struct css_driver *drv;
1085
1086         if (!sch->dev.driver)
1087                 return 0;
1088         drv = to_cssdriver(sch->dev.driver);
1089         return drv->restore ? drv->restore(sch) : 0;
1090 }
1091
1092 static struct dev_pm_ops css_pm_ops = {
1093         .prepare = css_pm_prepare,
1094         .complete = css_pm_complete,
1095         .freeze = css_pm_freeze,
1096         .thaw = css_pm_thaw,
1097         .restore = css_pm_restore,
1098 };
1099
1100 struct bus_type css_bus_type = {
1101         .name     = "css",
1102         .match    = css_bus_match,
1103         .probe    = css_probe,
1104         .remove   = css_remove,
1105         .shutdown = css_shutdown,
1106         .uevent   = css_uevent,
1107         .pm = &css_pm_ops,
1108 };
1109
1110 /**
1111  * css_driver_register - register a css driver
1112  * @cdrv: css driver to register
1113  *
1114  * This is mainly a wrapper around driver_register that sets name
1115  * and bus_type in the embedded struct device_driver correctly.
1116  */
1117 int css_driver_register(struct css_driver *cdrv)
1118 {
1119         cdrv->drv.name = cdrv->name;
1120         cdrv->drv.bus = &css_bus_type;
1121         cdrv->drv.owner = cdrv->owner;
1122         return driver_register(&cdrv->drv);
1123 }
1124 EXPORT_SYMBOL_GPL(css_driver_register);
1125
1126 /**
1127  * css_driver_unregister - unregister a css driver
1128  * @cdrv: css driver to unregister
1129  *
1130  * This is a wrapper around driver_unregister.
1131  */
1132 void css_driver_unregister(struct css_driver *cdrv)
1133 {
1134         driver_unregister(&cdrv->drv);
1135 }
1136 EXPORT_SYMBOL_GPL(css_driver_unregister);
1137
1138 subsys_initcall(init_channel_subsystem);
1139
1140 MODULE_LICENSE("GPL");
1141 EXPORT_SYMBOL(css_bus_type);