drivers/s390/cio/css.c

   1 // SPDX-License-Identifier: GPL-2.0
   2 /*
   3  * driver for channel subsystem
   4  *
   5  * Copyright IBM Corp. 2002, 2010
   6  *
   7  * Author(s): Arnd Bergmann (arndb@de.ibm.com)
   8  *            Cornelia Huck (cornelia.huck@de.ibm.com)
   9  */
  10
  11 #define KMSG_COMPONENT "cio"
  12 #define pr_fmt(fmt) KMSG_COMPONENT ": " fmt
  13
  14 #include <linux/export.h>
  15 #include <linux/init.h>
  16 #include <linux/device.h>
  17 #include <linux/slab.h>
  18 #include <linux/errno.h>
  19 #include <linux/list.h>
  20 #include <linux/reboot.h>
  21 #include <linux/suspend.h>
  22 #include <linux/proc_fs.h>
  23 #include <linux/genalloc.h>
  24 #include <linux/dma-mapping.h>
  25 #include <asm/isc.h>
  26 #include <asm/crw.h>
  27
  28 #include "css.h"
  29 #include "cio.h"
  30 #include "blacklist.h"
  31 #include "cio_debug.h"
  32 #include "ioasm.h"
  33 #include "chsc.h"
  34 #include "device.h"
  35 #include "idset.h"
  36 #include "chp.h"
  37
  38 int css_init_done = 0;
  39 int max_ssid;
  40
  41 #define MAX_CSS_IDX 0
  42 struct channel_subsystem *channel_subsystems[MAX_CSS_IDX + 1];
  43 static struct bus_type css_bus_type;
  44
  45 int
  46 for_each_subchannel(int(*fn)(struct subchannel_id, void *), void *data)
  47 {
  48         struct subchannel_id schid;
  49         int ret;
  50
  51         init_subchannel_id(&schid);
  52         do {
  53                 do {
  54                         ret = fn(schid, data);
  55                         if (ret)
  56                                 break;
  57                 } while (schid.sch_no++ < __MAX_SUBCHANNEL);
  58                 schid.sch_no = 0;
  59         } while (schid.ssid++ < max_ssid);
  60         return ret;
  61 }
  62
  63 struct cb_data {
  64         void *data;
  65         struct idset *set;
  66         int (*fn_known_sch)(struct subchannel *, void *);
  67         int (*fn_unknown_sch)(struct subchannel_id, void *);
  68 };
  69
  70 static int call_fn_known_sch(struct device *dev, void *data)
  71 {
  72         struct subchannel *sch = to_subchannel(dev);
  73         struct cb_data *cb = data;
  74         int rc = 0;
  75
  76         if (cb->set)
  77                 idset_sch_del(cb->set, sch->schid);
  78         if (cb->fn_known_sch)
  79                 rc = cb->fn_known_sch(sch, cb->data);
  80         return rc;
  81 }
  82
  83 static int call_fn_unknown_sch(struct subchannel_id schid, void *data)
  84 {
  85         struct cb_data *cb = data;
  86         int rc = 0;
  87
  88         if (idset_sch_contains(cb->set, schid))
  89                 rc = cb->fn_unknown_sch(schid, cb->data);
  90         return rc;
  91 }
  92
  93 static int call_fn_all_sch(struct subchannel_id schid, void *data)
  94 {
  95         struct cb_data *cb = data;
  96         struct subchannel *sch;
  97         int rc = 0;
  98
  99         sch = get_subchannel_by_schid(schid);
 100         if (sch) {
 101                 if (cb->fn_known_sch)
 102                         rc = cb->fn_known_sch(sch, cb->data);
 103                 put_device(&sch->dev);
 104         } else {
 105                 if (cb->fn_unknown_sch)
 106                         rc = cb->fn_unknown_sch(schid, cb->data);
 107         }
 108
 109         return rc;
 110 }
 111
 112 int for_each_subchannel_staged(int (*fn_known)(struct subchannel *, void *),
 113                                int (*fn_unknown)(struct subchannel_id,
 114                                void *), void *data)
 115 {
 116         struct cb_data cb;
 117         int rc;
 118
 119         cb.data = data;
 120         cb.fn_known_sch = fn_known;
 121         cb.fn_unknown_sch = fn_unknown;
 122
 123         if (fn_known && !fn_unknown) {
 124                 /* Skip idset allocation in case of known-only loop. */
 125                 cb.set = NULL;
 126                 return bus_for_each_dev(&css_bus_type, NULL, &cb,
 127                                         call_fn_known_sch);
 128         }
 129
 130         cb.set = idset_sch_new();
 131         if (!cb.set)
 132                 /* fall back to brute force scanning in case of oom */
 133                 return for_each_subchannel(call_fn_all_sch, &cb);
 134
 135         idset_fill(cb.set);
 136
 137         /* Process registered subchannels. */
 138         rc = bus_for_each_dev(&css_bus_type, NULL, &cb, call_fn_known_sch);
 139         if (rc)
 140                 goto out;
 141         /* Process unregistered subchannels. */
 142         if (fn_unknown)
 143                 rc = for_each_subchannel(call_fn_unknown_sch, &cb);
 144 out:
 145         idset_free(cb.set);
 146
 147         return rc;
 148 }
 149
 150 static void css_sch_todo(struct work_struct *work);
 151
 152 static int css_sch_create_locks(struct subchannel *sch)
 153 {
 154         sch->lock = kmalloc(sizeof(*sch->lock), GFP_KERNEL);
 155         if (!sch->lock)
 156                 return -ENOMEM;
 157
 158         spin_lock_init(sch->lock);
 159         mutex_init(&sch->reg_mutex);
 160
 161         return 0;
 162 }
 163
 164 static void css_subchannel_release(struct device *dev)
 165 {
 166         struct subchannel *sch = to_subchannel(dev);
 167
 168         sch->config.intparm = 0;
 169         cio_commit_config(sch);
 170         kfree(sch->driver_override);
 171         kfree(sch->lock);
 172         kfree(sch);
 173 }
 174
 175 static int css_validate_subchannel(struct subchannel_id schid,
 176                                    struct schib *schib)
 177 {
 178         int err;
 179
 180         switch (schib->pmcw.st) {
 181         case SUBCHANNEL_TYPE_IO:
 182         case SUBCHANNEL_TYPE_MSG:
 183                 if (!css_sch_is_valid(schib))
 184                         err = -ENODEV;
 185                 else if (is_blacklisted(schid.ssid, schib->pmcw.dev)) {
 186                         CIO_MSG_EVENT(6, "Blacklisted device detected "
 187                                       "at devno %04X, subchannel set %x\n",
 188                                       schib->pmcw.dev, schid.ssid);
 189                         err = -ENODEV;
 190                 } else
 191                         err = 0;
 192                 break;
 193         default:
 194                 err = 0;
 195         }
 196         if (err)
 197                 goto out;
 198
 199         CIO_MSG_EVENT(4, "Subchannel 0.%x.%04x reports subchannel type %04X\n",
 200                       schid.ssid, schid.sch_no, schib->pmcw.st);
 201 out:
 202         return err;
 203 }
 204
 205 struct subchannel *css_alloc_subchannel(struct subchannel_id schid,
 206                                         struct schib *schib)
 207 {
 208         struct subchannel *sch;
 209         int ret;
 210
 211         ret = css_validate_subchannel(schid, schib);
 212         if (ret < 0)
 213                 return ERR_PTR(ret);
 214
 215         sch = kzalloc(sizeof(*sch), GFP_KERNEL | GFP_DMA);
 216         if (!sch)
 217                 return ERR_PTR(-ENOMEM);
 218
 219         sch->schid = schid;
 220         sch->schib = *schib;
 221         sch->st = schib->pmcw.st;
 222
 223         ret = css_sch_create_locks(sch);
 224         if (ret)
 225                 goto err;
 226
 227         INIT_WORK(&sch->todo_work, css_sch_todo);
 228         sch->dev.release = &css_subchannel_release;
 229         device_initialize(&sch->dev);
 230         /*
 231          * The physical addresses of some the dma structures that can
 232          * belong to a subchannel need to fit 31 bit width (e.g. ccw).
 233          */
 234         sch->dev.coherent_dma_mask = DMA_BIT_MASK(31);
 235         sch->dev.dma_mask = &sch->dev.coherent_dma_mask;
 236         return sch;
 237
 238 err:
 239         kfree(sch);
 240         return ERR_PTR(ret);
 241 }
 242
 243 static int css_sch_device_register(struct subchannel *sch)
 244 {
 245         int ret;
 246
 247         mutex_lock(&sch->reg_mutex);
 248         dev_set_name(&sch->dev, "0.%x.%04x", sch->schid.ssid,
 249                      sch->schid.sch_no);
 250         ret = device_add(&sch->dev);
 251         mutex_unlock(&sch->reg_mutex);
 252         return ret;
 253 }
 254
 255 /**
 256  * css_sch_device_unregister - unregister a subchannel
 257  * @sch: subchannel to be unregistered
 258  */
 259 void css_sch_device_unregister(struct subchannel *sch)
 260 {
 261         mutex_lock(&sch->reg_mutex);
 262         if (device_is_registered(&sch->dev))
 263                 device_unregister(&sch->dev);
 264         mutex_unlock(&sch->reg_mutex);
 265 }
 266 EXPORT_SYMBOL_GPL(css_sch_device_unregister);
 267
 268 static void ssd_from_pmcw(struct chsc_ssd_info *ssd, struct pmcw *pmcw)
 269 {
 270         int i;
 271         int mask;
 272
 273         memset(ssd, 0, sizeof(struct chsc_ssd_info));
 274         ssd->path_mask = pmcw->pim;
 275         for (i = 0; i < 8; i++) {
 276                 mask = 0x80 >> i;
 277                 if (pmcw->pim & mask) {
 278                         chp_id_init(&ssd->chpid[i]);
 279                         ssd->chpid[i].id = pmcw->chpid[i];
 280                 }
 281         }
 282 }
 283
 284 static void ssd_register_chpids(struct chsc_ssd_info *ssd)
 285 {
 286         int i;
 287         int mask;
 288
 289         for (i = 0; i < 8; i++) {
 290                 mask = 0x80 >> i;
 291                 if (ssd->path_mask & mask)
 292                         chp_new(ssd->chpid[i]);
 293         }
 294 }
 295
 296 void css_update_ssd_info(struct subchannel *sch)
 297 {
 298         int ret;
 299
 300         ret = chsc_get_ssd_info(sch->schid, &sch->ssd_info);
 301         if (ret)
 302                 ssd_from_pmcw(&sch->ssd_info, &sch->schib.pmcw);
 303
 304         ssd_register_chpids(&sch->ssd_info);
 305 }
 306
 307 static ssize_t type_show(struct device *dev, struct device_attribute *attr,
 308                          char *buf)
 309 {
 310         struct subchannel *sch = to_subchannel(dev);
 311
 312         return sprintf(buf, "%01x\n", sch->st);
 313 }
 314
 315 static DEVICE_ATTR_RO(type);
 316
 317 static ssize_t modalias_show(struct device *dev, struct device_attribute *attr,
 318                              char *buf)
 319 {
 320         struct subchannel *sch = to_subchannel(dev);
 321
 322         return sprintf(buf, "css:t%01X\n", sch->st);
 323 }
 324
 325 static DEVICE_ATTR_RO(modalias);
 326
 327 static ssize_t driver_override_store(struct device *dev,
 328                                      struct device_attribute *attr,
 329                                      const char *buf, size_t count)
 330 {
 331         struct subchannel *sch = to_subchannel(dev);
 332         char *driver_override, *old, *cp;
 333
 334         /* We need to keep extra room for a newline */
 335         if (count >= (PAGE_SIZE - 1))
 336                 return -EINVAL;
 337
 338         driver_override = kstrndup(buf, count, GFP_KERNEL);
 339         if (!driver_override)
 340                 return -ENOMEM;
 341
 342         cp = strchr(driver_override, '\n');
 343         if (cp)
 344                 *cp = '\0';
 345
 346         device_lock(dev);
 347         old = sch->driver_override;
 348         if (strlen(driver_override)) {
 349                 sch->driver_override = driver_override;
 350         } else {
 351                 kfree(driver_override);
 352                 sch->driver_override = NULL;
 353         }
 354         device_unlock(dev);
 355
 356         kfree(old);
 357
 358         return count;
 359 }
 360
 361 static ssize_t driver_override_show(struct device *dev,
 362                                     struct device_attribute *attr, char *buf)
 363 {
 364         struct subchannel *sch = to_subchannel(dev);
 365         ssize_t len;
 366
 367         device_lock(dev);
 368         len = snprintf(buf, PAGE_SIZE, "%s\n", sch->driver_override);
 369         device_unlock(dev);
 370         return len;
 371 }
 372 static DEVICE_ATTR_RW(driver_override);
 373
 374 static struct attribute *subch_attrs[] = {
 375         &dev_attr_type.attr,
 376         &dev_attr_modalias.attr,
 377         &dev_attr_driver_override.attr,
 378         NULL,
 379 };
 380
 381 static struct attribute_group subch_attr_group = {
 382         .attrs = subch_attrs,
 383 };
 384
 385 static const struct attribute_group *default_subch_attr_groups[] = {
 386         &subch_attr_group,
 387         NULL,
 388 };
 389
 390 static ssize_t chpids_show(struct device *dev,
 391                            struct device_attribute *attr,
 392                            char *buf)
 393 {
 394         struct subchannel *sch = to_subchannel(dev);
 395         struct chsc_ssd_info *ssd = &sch->ssd_info;
 396         ssize_t ret = 0;
 397         int mask;
 398         int chp;
 399
 400         for (chp = 0; chp < 8; chp++) {
 401                 mask = 0x80 >> chp;
 402                 if (ssd->path_mask & mask)
 403                         ret += sprintf(buf + ret, "%02x ", ssd->chpid[chp].id);
 404                 else
 405                         ret += sprintf(buf + ret, "00 ");
 406         }
 407         ret += sprintf(buf + ret, "\n");
 408         return ret;
 409 }
 410 static DEVICE_ATTR_RO(chpids);
 411
 412 static ssize_t pimpampom_show(struct device *dev,
 413                               struct device_attribute *attr,
 414                               char *buf)
 415 {
 416         struct subchannel *sch = to_subchannel(dev);
 417         struct pmcw *pmcw = &sch->schib.pmcw;
 418
 419         return sprintf(buf, "%02x %02x %02x\n",
 420                        pmcw->pim, pmcw->pam, pmcw->pom);
 421 }
 422 static DEVICE_ATTR_RO(pimpampom);
 423
 424 static struct attribute *io_subchannel_type_attrs[] = {
 425         &dev_attr_chpids.attr,
 426         &dev_attr_pimpampom.attr,
 427         NULL,
 428 };
 429 ATTRIBUTE_GROUPS(io_subchannel_type);
 430
 431 static const struct device_type io_subchannel_type = {
 432         .groups = io_subchannel_type_groups,
 433 };
 434
 435 int css_register_subchannel(struct subchannel *sch)
 436 {
 437         int ret;
 438
 439         /* Initialize the subchannel structure */
 440         sch->dev.parent = &channel_subsystems[0]->device;
 441         sch->dev.bus = &css_bus_type;
 442         sch->dev.groups = default_subch_attr_groups;
 443
 444         if (sch->st == SUBCHANNEL_TYPE_IO)
 445                 sch->dev.type = &io_subchannel_type;
 446
 447         /*
 448          * We don't want to generate uevents for I/O subchannels that don't
 449          * have a working ccw device behind them since they will be
 450          * unregistered before they can be used anyway, so we delay the add
 451          * uevent until after device recognition was successful.
 452          * Note that we suppress the uevent for all subchannel types;
 453          * the subchannel driver can decide itself when it wants to inform
 454          * userspace of its existence.
 455          */
 456         dev_set_uevent_suppress(&sch->dev, 1);
 457         css_update_ssd_info(sch);
 458         /* make it known to the system */
 459         ret = css_sch_device_register(sch);
 460         if (ret) {
 461                 CIO_MSG_EVENT(0, "Could not register sch 0.%x.%04x: %d\n",
 462                               sch->schid.ssid, sch->schid.sch_no, ret);
 463                 return ret;
 464         }
 465         if (!sch->driver) {
 466                 /*
 467                  * No driver matched. Generate the uevent now so that
 468                  * a fitting driver module may be loaded based on the
 469                  * modalias.
 470                  */
 471                 dev_set_uevent_suppress(&sch->dev, 0);
 472                 kobject_uevent(&sch->dev.kobj, KOBJ_ADD);
 473         }
 474         return ret;
 475 }
 476
 477 static int css_probe_device(struct subchannel_id schid, struct schib *schib)
 478 {
 479         struct subchannel *sch;
 480         int ret;
 481
 482         sch = css_alloc_subchannel(schid, schib);
 483         if (IS_ERR(sch))
 484                 return PTR_ERR(sch);
 485
 486         ret = css_register_subchannel(sch);
 487         if (ret)
 488                 put_device(&sch->dev);
 489
 490         return ret;
 491 }
 492
 493 static int
 494 check_subchannel(struct device *dev, const void *data)
 495 {
 496         struct subchannel *sch;
 497         struct subchannel_id *schid = (void *)data;
 498
 499         sch = to_subchannel(dev);
 500         return schid_equal(&sch->schid, schid);
 501 }
 502
 503 struct subchannel *
 504 get_subchannel_by_schid(struct subchannel_id schid)
 505 {
 506         struct device *dev;
 507
 508         dev = bus_find_device(&css_bus_type, NULL,
 509                               &schid, check_subchannel);
 510
 511         return dev ? to_subchannel(dev) : NULL;
 512 }
 513
 514 /**
 515  * css_sch_is_valid() - check if a subchannel is valid
 516  * @schib: subchannel information block for the subchannel
 517  */
 518 int css_sch_is_valid(struct schib *schib)
 519 {
 520         if ((schib->pmcw.st == SUBCHANNEL_TYPE_IO) && !schib->pmcw.dnv)
 521                 return 0;
 522         if ((schib->pmcw.st == SUBCHANNEL_TYPE_MSG) && !schib->pmcw.w)
 523                 return 0;
 524         return 1;
 525 }
 526 EXPORT_SYMBOL_GPL(css_sch_is_valid);
 527
 528 static int css_evaluate_new_subchannel(struct subchannel_id schid, int slow)
 529 {
 530         struct schib schib;
 531         int ccode;
 532
 533         if (!slow) {
 534                 /* Will be done on the slow path. */
 535                 return -EAGAIN;
 536         }
 537         /*
 538          * The first subchannel that is not-operational (ccode==3)
 539          * indicates that there aren't any more devices available.
 540          * If stsch gets an exception, it means the current subchannel set
 541          * is not valid.
 542          */
 543         ccode = stsch(schid, &schib);
 544         if (ccode)
 545                 return (ccode == 3) ? -ENXIO : ccode;
 546
 547         return css_probe_device(schid, &schib);
 548 }
 549
 550 static int css_evaluate_known_subchannel(struct subchannel *sch, int slow)
 551 {
 552         int ret = 0;
 553
 554         if (sch->driver) {
 555                 if (sch->driver->sch_event)
 556                         ret = sch->driver->sch_event(sch, slow);
 557                 else
 558                         dev_dbg(&sch->dev,
 559                                 "Got subchannel machine check but "
 560                                 "no sch_event handler provided.\n");
 561         }
 562         if (ret != 0 && ret != -EAGAIN) {
 563                 CIO_MSG_EVENT(2, "eval: sch 0.%x.%04x, rc=%d\n",
 564                               sch->schid.ssid, sch->schid.sch_no, ret);
 565         }
 566         return ret;
 567 }
 568
 569 static void css_evaluate_subchannel(struct subchannel_id schid, int slow)
 570 {
 571         struct subchannel *sch;
 572         int ret;
 573
 574         sch = get_subchannel_by_schid(schid);
 575         if (sch) {
 576                 ret = css_evaluate_known_subchannel(sch, slow);
 577                 put_device(&sch->dev);
 578         } else
 579                 ret = css_evaluate_new_subchannel(schid, slow);
 580         if (ret == -EAGAIN)
 581                 css_schedule_eval(schid);
 582 }
 583
 584 /**
 585  * css_sched_sch_todo - schedule a subchannel operation
 586  * @sch: subchannel
 587  * @todo: todo
 588  *
 589  * Schedule the operation identified by @todo to be performed on the slow path
 590  * workqueue. Do nothing if another operation with higher priority is already
 591  * scheduled. Needs to be called with subchannel lock held.
 592  */
 593 void css_sched_sch_todo(struct subchannel *sch, enum sch_todo todo)
 594 {
 595         CIO_MSG_EVENT(4, "sch_todo: sched sch=0.%x.%04x todo=%d\n",
 596                       sch->schid.ssid, sch->schid.sch_no, todo);
 597         if (sch->todo >= todo)
 598                 return;
 599         /* Get workqueue ref. */
 600         if (!get_device(&sch->dev))
 601                 return;
 602         sch->todo = todo;
 603         if (!queue_work(cio_work_q, &sch->todo_work)) {
 604                 /* Already queued, release workqueue ref. */
 605                 put_device(&sch->dev);
 606         }
 607 }
 608 EXPORT_SYMBOL_GPL(css_sched_sch_todo);
 609
 610 static void css_sch_todo(struct work_struct *work)
 611 {
 612         struct subchannel *sch;
 613         enum sch_todo todo;
 614         int ret;
 615
 616         sch = container_of(work, struct subchannel, todo_work);
 617         /* Find out todo. */
 618         spin_lock_irq(sch->lock);
 619         todo = sch->todo;
 620         CIO_MSG_EVENT(4, "sch_todo: sch=0.%x.%04x, todo=%d\n", sch->schid.ssid,
 621                       sch->schid.sch_no, todo);
 622         sch->todo = SCH_TODO_NOTHING;
 623         spin_unlock_irq(sch->lock);
 624         /* Perform todo. */
 625         switch (todo) {
 626         case SCH_TODO_NOTHING:
 627                 break;
 628         case SCH_TODO_EVAL:
 629                 ret = css_evaluate_known_subchannel(sch, 1);
 630                 if (ret == -EAGAIN) {
 631                         spin_lock_irq(sch->lock);
 632                         css_sched_sch_todo(sch, todo);
 633                         spin_unlock_irq(sch->lock);
 634                 }
 635                 break;
 636         case SCH_TODO_UNREG:
 637                 css_sch_device_unregister(sch);
 638                 break;
 639         }
 640         /* Release workqueue ref. */
 641         put_device(&sch->dev);
 642 }
 643
 644 static struct idset *slow_subchannel_set;
 645 static spinlock_t slow_subchannel_lock;
 646 static wait_queue_head_t css_eval_wq;
 647 static atomic_t css_eval_scheduled;
 648
 649 static int __init slow_subchannel_init(void)
 650 {
 651         spin_lock_init(&slow_subchannel_lock);
 652         atomic_set(&css_eval_scheduled, 0);
 653         init_waitqueue_head(&css_eval_wq);
 654         slow_subchannel_set = idset_sch_new();
 655         if (!slow_subchannel_set) {
 656                 CIO_MSG_EVENT(0, "could not allocate slow subchannel set\n");
 657                 return -ENOMEM;
 658         }
 659         return 0;
 660 }
 661
 662 static int slow_eval_known_fn(struct subchannel *sch, void *data)
 663 {
 664         int eval;
 665         int rc;
 666
 667         spin_lock_irq(&slow_subchannel_lock);
 668         eval = idset_sch_contains(slow_subchannel_set, sch->schid);
 669         idset_sch_del(slow_subchannel_set, sch->schid);
 670         spin_unlock_irq(&slow_subchannel_lock);
 671         if (eval) {
 672                 rc = css_evaluate_known_subchannel(sch, 1);
 673                 if (rc == -EAGAIN)
 674                         css_schedule_eval(sch->schid);
 675         }
 676         return 0;
 677 }
 678
 679 static int slow_eval_unknown_fn(struct subchannel_id schid, void *data)
 680 {
 681         int eval;
 682         int rc = 0;
 683
 684         spin_lock_irq(&slow_subchannel_lock);
 685         eval = idset_sch_contains(slow_subchannel_set, schid);
 686         idset_sch_del(slow_subchannel_set, schid);
 687         spin_unlock_irq(&slow_subchannel_lock);
 688         if (eval) {
 689                 rc = css_evaluate_new_subchannel(schid, 1);
 690                 switch (rc) {
 691                 case -EAGAIN:
 692                         css_schedule_eval(schid);
 693                         rc = 0;
 694                         break;
 695                 case -ENXIO:
 696                 case -ENOMEM:
 697                 case -EIO:
 698                         /* These should abort looping */
 699                         spin_lock_irq(&slow_subchannel_lock);
 700                         idset_sch_del_subseq(slow_subchannel_set, schid);
 701                         spin_unlock_irq(&slow_subchannel_lock);
 702                         break;
 703                 default:
 704                         rc = 0;
 705                 }
 706                 /* Allow scheduling here since the containing loop might
 707                  * take a while.  */
 708                 cond_resched();
 709         }
 710         return rc;
 711 }
 712
 713 static void css_slow_path_func(struct work_struct *unused)
 714 {
 715         unsigned long flags;
 716
 717         CIO_TRACE_EVENT(4, "slowpath");
 718         for_each_subchannel_staged(slow_eval_known_fn, slow_eval_unknown_fn,
 719                                    NULL);
 720         spin_lock_irqsave(&slow_subchannel_lock, flags);
 721         if (idset_is_empty(slow_subchannel_set)) {
 722                 atomic_set(&css_eval_scheduled, 0);
 723                 wake_up(&css_eval_wq);
 724         }
 725         spin_unlock_irqrestore(&slow_subchannel_lock, flags);
 726 }
 727
 728 static DECLARE_DELAYED_WORK(slow_path_work, css_slow_path_func);
 729 struct workqueue_struct *cio_work_q;
 730
 731 void css_schedule_eval(struct subchannel_id schid)
 732 {
 733         unsigned long flags;
 734
 735         spin_lock_irqsave(&slow_subchannel_lock, flags);
 736         idset_sch_add(slow_subchannel_set, schid);
 737         atomic_set(&css_eval_scheduled, 1);
 738         queue_delayed_work(cio_work_q, &slow_path_work, 0);
 739         spin_unlock_irqrestore(&slow_subchannel_lock, flags);
 740 }
 741
 742 void css_schedule_eval_all(void)
 743 {
 744         unsigned long flags;
 745
 746         spin_lock_irqsave(&slow_subchannel_lock, flags);
 747         idset_fill(slow_subchannel_set);
 748         atomic_set(&css_eval_scheduled, 1);
 749         queue_delayed_work(cio_work_q, &slow_path_work, 0);
 750         spin_unlock_irqrestore(&slow_subchannel_lock, flags);
 751 }
 752
 753 static int __unset_registered(struct device *dev, void *data)
 754 {
 755         struct idset *set = data;
 756         struct subchannel *sch = to_subchannel(dev);
 757
 758         idset_sch_del(set, sch->schid);
 759         return 0;
 760 }
 761
 762 void css_schedule_eval_all_unreg(unsigned long delay)
 763 {
 764         unsigned long flags;
 765         struct idset *unreg_set;
 766
 767         /* Find unregistered subchannels. */
 768         unreg_set = idset_sch_new();
 769         if (!unreg_set) {
 770                 /* Fallback. */
 771                 css_schedule_eval_all();
 772                 return;
 773         }
 774         idset_fill(unreg_set);
 775         bus_for_each_dev(&css_bus_type, NULL, unreg_set, __unset_registered);
 776         /* Apply to slow_subchannel_set. */
 777         spin_lock_irqsave(&slow_subchannel_lock, flags);
 778         idset_add_set(slow_subchannel_set, unreg_set);
 779         atomic_set(&css_eval_scheduled, 1);
 780         queue_delayed_work(cio_work_q, &slow_path_work, delay);
 781         spin_unlock_irqrestore(&slow_subchannel_lock, flags);
 782         idset_free(unreg_set);
 783 }
 784
 785 void css_wait_for_slow_path(void)
 786 {
 787         flush_workqueue(cio_work_q);
 788 }
 789
 790 /* Schedule reprobing of all unregistered subchannels. */
 791 void css_schedule_reprobe(void)
 792 {
 793         /* Schedule with a delay to allow merging of subsequent calls. */
 794         css_schedule_eval_all_unreg(1 * HZ);
 795 }
 796 EXPORT_SYMBOL_GPL(css_schedule_reprobe);
 797
 798 /*
 799  * Called from the machine check handler for subchannel report words.
 800  */
 801 static void css_process_crw(struct crw *crw0, struct crw *crw1, int overflow)
 802 {
 803         struct subchannel_id mchk_schid;
 804         struct subchannel *sch;
 805
 806         if (overflow) {
 807                 css_schedule_eval_all();
 808                 return;
 809         }
 810         CIO_CRW_EVENT(2, "CRW0 reports slct=%d, oflw=%d, "
 811                       "chn=%d, rsc=%X, anc=%d, erc=%X, rsid=%X\n",
 812                       crw0->slct, crw0->oflw, crw0->chn, crw0->rsc, crw0->anc,
 813                       crw0->erc, crw0->rsid);
 814         if (crw1)
 815                 CIO_CRW_EVENT(2, "CRW1 reports slct=%d, oflw=%d, "
 816                               "chn=%d, rsc=%X, anc=%d, erc=%X, rsid=%X\n",
 817                               crw1->slct, crw1->oflw, crw1->chn, crw1->rsc,
 818                               crw1->anc, crw1->erc, crw1->rsid);
 819         init_subchannel_id(&mchk_schid);
 820         mchk_schid.sch_no = crw0->rsid;
 821         if (crw1)
 822                 mchk_schid.ssid = (crw1->rsid >> 4) & 3;
 823
 824         if (crw0->erc == CRW_ERC_PMOD) {
 825                 sch = get_subchannel_by_schid(mchk_schid);
 826                 if (sch) {
 827                         css_update_ssd_info(sch);
 828                         put_device(&sch->dev);
 829                 }
 830         }
 831         /*
 832          * Since we are always presented with IPI in the CRW, we have to
 833          * use stsch() to find out if the subchannel in question has come
 834          * or gone.
 835          */
 836         css_evaluate_subchannel(mchk_schid, 0);
 837 }
 838
 839 static void __init
 840 css_generate_pgid(struct channel_subsystem *css, u32 tod_high)
 841 {
 842         struct cpuid cpu_id;
 843
 844         if (css_general_characteristics.mcss) {
 845                 css->global_pgid.pgid_high.ext_cssid.version = 0x80;
 846                 css->global_pgid.pgid_high.ext_cssid.cssid =
 847                         (css->cssid < 0) ? 0 : css->cssid;
 848         } else {
 849                 css->global_pgid.pgid_high.cpu_addr = stap();
 850         }
 851         get_cpu_id(&cpu_id);
 852         css->global_pgid.cpu_id = cpu_id.ident;
 853         css->global_pgid.cpu_model = cpu_id.machine;
 854         css->global_pgid.tod_high = tod_high;
 855 }
 856
 857 static void channel_subsystem_release(struct device *dev)
 858 {
 859         struct channel_subsystem *css = to_css(dev);
 860
 861         mutex_destroy(&css->mutex);
 862         kfree(css);
 863 }
 864
 865 static ssize_t real_cssid_show(struct device *dev, struct device_attribute *a,
 866                                char *buf)
 867 {
 868         struct channel_subsystem *css = to_css(dev);
 869
 870         if (css->cssid < 0)
 871                 return -EINVAL;
 872
 873         return sprintf(buf, "%x\n", css->cssid);
 874 }
 875 static DEVICE_ATTR_RO(real_cssid);
 876
 877 static ssize_t cm_enable_show(struct device *dev, struct device_attribute *a,
 878                               char *buf)
 879 {
 880         struct channel_subsystem *css = to_css(dev);
 881         int ret;
 882
 883         mutex_lock(&css->mutex);
 884         ret = sprintf(buf, "%x\n", css->cm_enabled);
 885         mutex_unlock(&css->mutex);
 886         return ret;
 887 }
 888
 889 static ssize_t cm_enable_store(struct device *dev, struct device_attribute *a,
 890                                const char *buf, size_t count)
 891 {
 892         struct channel_subsystem *css = to_css(dev);
 893         unsigned long val;
 894         int ret;
 895
 896         ret = kstrtoul(buf, 16, &val);
 897         if (ret)
 898                 return ret;
 899         mutex_lock(&css->mutex);
 900         switch (val) {
 901         case 0:
 902                 ret = css->cm_enabled ? chsc_secm(css, 0) : 0;
 903                 break;
 904         case 1:
 905                 ret = css->cm_enabled ? 0 : chsc_secm(css, 1);
 906                 break;
 907         default:
 908                 ret = -EINVAL;
 909         }
 910         mutex_unlock(&css->mutex);
 911         return ret < 0 ? ret : count;
 912 }
 913 static DEVICE_ATTR_RW(cm_enable);
 914
 915 static umode_t cm_enable_mode(struct kobject *kobj, struct attribute *attr,
 916                               int index)
 917 {
 918         return css_chsc_characteristics.secm ? attr->mode : 0;
 919 }
 920
 921 static struct attribute *cssdev_attrs[] = {
 922         &dev_attr_real_cssid.attr,
 923         NULL,
 924 };
 925
 926 static struct attribute_group cssdev_attr_group = {
 927         .attrs = cssdev_attrs,
 928 };
 929
 930 static struct attribute *cssdev_cm_attrs[] = {
 931         &dev_attr_cm_enable.attr,
 932         NULL,
 933 };
 934
 935 static struct attribute_group cssdev_cm_attr_group = {
 936         .attrs = cssdev_cm_attrs,
 937         .is_visible = cm_enable_mode,
 938 };
 939
 940 static const struct attribute_group *cssdev_attr_groups[] = {
 941         &cssdev_attr_group,
 942         &cssdev_cm_attr_group,
 943         NULL,
 944 };
 945
 946 static int __init setup_css(int nr)
 947 {
 948         struct channel_subsystem *css;
 949         int ret;
 950
 951         css = kzalloc(sizeof(*css), GFP_KERNEL);
 952         if (!css)
 953                 return -ENOMEM;
 954
 955         channel_subsystems[nr] = css;
 956         dev_set_name(&css->device, "css%x", nr);
 957         css->device.groups = cssdev_attr_groups;
 958         css->device.release = channel_subsystem_release;
 959         /*
 960          * We currently allocate notifier bits with this (using
 961          * css->device as the device argument with the DMA API)
 962          * and are fine with 64 bit addresses.
 963          */
 964         css->device.coherent_dma_mask = DMA_BIT_MASK(64);
 965         css->device.dma_mask = &css->device.coherent_dma_mask;
 966
 967         mutex_init(&css->mutex);
 968         css->cssid = chsc_get_cssid(nr);
 969         css_generate_pgid(css, (u32) (get_tod_clock() >> 32));
 970
 971         ret = device_register(&css->device);
 972         if (ret) {
 973                 put_device(&css->device);
 974                 goto out_err;
 975         }
 976
 977         css->pseudo_subchannel = kzalloc(sizeof(*css->pseudo_subchannel),
 978                                          GFP_KERNEL);
 979         if (!css->pseudo_subchannel) {
 980                 device_unregister(&css->device);
 981                 ret = -ENOMEM;
 982                 goto out_err;
 983         }
 984
 985         css->pseudo_subchannel->dev.parent = &css->device;
 986         css->pseudo_subchannel->dev.release = css_subchannel_release;
 987         mutex_init(&css->pseudo_subchannel->reg_mutex);
 988         ret = css_sch_create_locks(css->pseudo_subchannel);
 989         if (ret) {
 990                 kfree(css->pseudo_subchannel);
 991                 device_unregister(&css->device);
 992                 goto out_err;
 993         }
 994
 995         dev_set_name(&css->pseudo_subchannel->dev, "defunct");
 996         ret = device_register(&css->pseudo_subchannel->dev);
 997         if (ret) {
 998                 put_device(&css->pseudo_subchannel->dev);
 999                 device_unregister(&css->device);
1000                 goto out_err;
1001         }
1002
1003         return ret;
1004 out_err:
1005         channel_subsystems[nr] = NULL;
1006         return ret;
1007 }
1008
1009 static int css_reboot_event(struct notifier_block *this,
1010                             unsigned long event,
1011                             void *ptr)
1012 {
1013         struct channel_subsystem *css;
1014         int ret;
1015
1016         ret = NOTIFY_DONE;
1017         for_each_css(css) {
1018                 mutex_lock(&css->mutex);
1019                 if (css->cm_enabled)
1020                         if (chsc_secm(css, 0))
1021                                 ret = NOTIFY_BAD;
1022                 mutex_unlock(&css->mutex);
1023         }
1024
1025         return ret;
1026 }
1027
1028 static struct notifier_block css_reboot_notifier = {
1029         .notifier_call = css_reboot_event,
1030 };
1031
1032 /*
1033  * Since the css devices are neither on a bus nor have a class
1034  * nor have a special device type, we cannot stop/restart channel
1035  * path measurements via the normal suspend/resume callbacks, but have
1036  * to use notifiers.
1037  */
1038 static int css_power_event(struct notifier_block *this, unsigned long event,
1039                            void *ptr)
1040 {
1041         struct channel_subsystem *css;
1042         int ret;
1043
1044         switch (event) {
1045         case PM_HIBERNATION_PREPARE:
1046         case PM_SUSPEND_PREPARE:
1047                 ret = NOTIFY_DONE;
1048                 for_each_css(css) {
1049                         mutex_lock(&css->mutex);
1050                         if (!css->cm_enabled) {
1051                                 mutex_unlock(&css->mutex);
1052                                 continue;
1053                         }
1054                         ret = __chsc_do_secm(css, 0);
1055                         ret = notifier_from_errno(ret);
1056                         mutex_unlock(&css->mutex);
1057                 }
1058                 break;
1059         case PM_POST_HIBERNATION:
1060         case PM_POST_SUSPEND:
1061                 ret = NOTIFY_DONE;
1062                 for_each_css(css) {
1063                         mutex_lock(&css->mutex);
1064                         if (!css->cm_enabled) {
1065                                 mutex_unlock(&css->mutex);
1066                                 continue;
1067                         }
1068                         ret = __chsc_do_secm(css, 1);
1069                         ret = notifier_from_errno(ret);
1070                         mutex_unlock(&css->mutex);
1071                 }
1072                 /* search for subchannels, which appeared during hibernation */
1073                 css_schedule_reprobe();
1074                 break;
1075         default:
1076                 ret = NOTIFY_DONE;
1077         }
1078         return ret;
1079
1080 }
1081 static struct notifier_block css_power_notifier = {
1082         .notifier_call = css_power_event,
1083 };
1084
1085 #define  CIO_DMA_GFP (GFP_KERNEL | __GFP_ZERO)
1086 static struct gen_pool *cio_dma_pool;
1087
1088 /* Currently cio supports only a single css */
1089 struct device *cio_get_dma_css_dev(void)
1090 {
1091         return &channel_subsystems[0]->device;
1092 }
1093
1094 struct gen_pool *cio_gp_dma_create(struct device *dma_dev, int nr_pages)
1095 {
1096         struct gen_pool *gp_dma;
1097         void *cpu_addr;
1098         dma_addr_t dma_addr;
1099         int i;
1100
1101         gp_dma = gen_pool_create(3, -1);
1102         if (!gp_dma)
1103                 return NULL;
1104         for (i = 0; i < nr_pages; ++i) {
1105                 cpu_addr = dma_alloc_coherent(dma_dev, PAGE_SIZE, &dma_addr,
1106                                               CIO_DMA_GFP);
1107                 if (!cpu_addr)
1108                         return gp_dma;
1109                 gen_pool_add_virt(gp_dma, (unsigned long) cpu_addr,
1110                                   dma_addr, PAGE_SIZE, -1);
1111         }
1112         return gp_dma;
1113 }
1114
1115 static void __gp_dma_free_dma(struct gen_pool *pool,
1116                               struct gen_pool_chunk *chunk, void *data)
1117 {
1118         size_t chunk_size = chunk->end_addr - chunk->start_addr + 1;
1119
1120         dma_free_coherent((struct device *) data, chunk_size,
1121                          (void *) chunk->start_addr,
1122                          (dma_addr_t) chunk->phys_addr);
1123 }
1124
1125 void cio_gp_dma_destroy(struct gen_pool *gp_dma, struct device *dma_dev)
1126 {
1127         if (!gp_dma)
1128                 return;
1129         /* this is quite ugly but no better idea */
1130         gen_pool_for_each_chunk(gp_dma, __gp_dma_free_dma, dma_dev);
1131         gen_pool_destroy(gp_dma);
1132 }
1133
1134 static int cio_dma_pool_init(void)
1135 {
1136         /* No need to free up the resources: compiled in */
1137         cio_dma_pool = cio_gp_dma_create(cio_get_dma_css_dev(), 1);
1138         if (!cio_dma_pool)
1139                 return -ENOMEM;
1140         return 0;
1141 }
1142
1143 void *cio_gp_dma_zalloc(struct gen_pool *gp_dma, struct device *dma_dev,
1144                         size_t size)
1145 {
1146         dma_addr_t dma_addr;
1147         unsigned long addr;
1148         size_t chunk_size;
1149
1150         if (!gp_dma)
1151                 return NULL;
1152         addr = gen_pool_alloc(gp_dma, size);
1153         while (!addr) {
1154                 chunk_size = round_up(size, PAGE_SIZE);
1155                 addr = (unsigned long) dma_alloc_coherent(dma_dev,
1156                                          chunk_size, &dma_addr, CIO_DMA_GFP);
1157                 if (!addr)
1158                         return NULL;
1159                 gen_pool_add_virt(gp_dma, addr, dma_addr, chunk_size, -1);
1160                 addr = gen_pool_alloc(gp_dma, size);
1161         }
1162         return (void *) addr;
1163 }
1164
1165 void cio_gp_dma_free(struct gen_pool *gp_dma, void *cpu_addr, size_t size)
1166 {
1167         if (!cpu_addr)
1168                 return;
1169         memset(cpu_addr, 0, size);
1170         gen_pool_free(gp_dma, (unsigned long) cpu_addr, size);
1171 }
1172
1173 /*
1174  * Allocate dma memory from the css global pool. Intended for memory not
1175  * specific to any single device within the css. The allocated memory
1176  * is not guaranteed to be 31-bit addressable.
1177  *
1178  * Caution: Not suitable for early stuff like console.
1179  */
1180 void *cio_dma_zalloc(size_t size)
1181 {
1182         return cio_gp_dma_zalloc(cio_dma_pool, cio_get_dma_css_dev(), size);
1183 }
1184
1185 void cio_dma_free(void *cpu_addr, size_t size)
1186 {
1187         cio_gp_dma_free(cio_dma_pool, cpu_addr, size);
1188 }
1189
1190 /*
1191  * Now that the driver core is running, we can setup our channel subsystem.
1192  * The struct subchannel's are created during probing.
1193  */
1194 static int __init css_bus_init(void)
1195 {
1196         int ret, i;
1197
1198         ret = chsc_init();
1199         if (ret)
1200                 return ret;
1201
1202         chsc_determine_css_characteristics();
1203         /* Try to enable MSS. */
1204         ret = chsc_enable_facility(CHSC_SDA_OC_MSS);
1205         if (ret)
1206                 max_ssid = 0;
1207         else /* Success. */
1208                 max_ssid = __MAX_SSID;
1209
1210         ret = slow_subchannel_init();
1211         if (ret)
1212                 goto out;
1213
1214         ret = crw_register_handler(CRW_RSC_SCH, css_process_crw);
1215         if (ret)
1216                 goto out;
1217
1218         if ((ret = bus_register(&css_bus_type)))
1219                 goto out;
1220
1221         /* Setup css structure. */
1222         for (i = 0; i <= MAX_CSS_IDX; i++) {
1223                 ret = setup_css(i);
1224                 if (ret)
1225                         goto out_unregister;
1226         }
1227         ret = register_reboot_notifier(&css_reboot_notifier);
1228         if (ret)
1229                 goto out_unregister;
1230         ret = register_pm_notifier(&css_power_notifier);
1231         if (ret)
1232                 goto out_unregister_rn;
1233         ret = cio_dma_pool_init();
1234         if (ret)
1235                 goto out_unregister_pmn;
1236         airq_init();
1237         css_init_done = 1;
1238
1239         /* Enable default isc for I/O subchannels. */
1240         isc_register(IO_SCH_ISC);
1241
1242         return 0;
1243 out_unregister_pmn:
1244         unregister_pm_notifier(&css_power_notifier);
1245 out_unregister_rn:
1246         unregister_reboot_notifier(&css_reboot_notifier);
1247 out_unregister:
1248         while (i-- > 0) {
1249                 struct channel_subsystem *css = channel_subsystems[i];
1250                 device_unregister(&css->pseudo_subchannel->dev);
1251                 device_unregister(&css->device);
1252         }
1253         bus_unregister(&css_bus_type);
1254 out:
1255         crw_unregister_handler(CRW_RSC_SCH);
1256         idset_free(slow_subchannel_set);
1257         chsc_init_cleanup();
1258         pr_alert("The CSS device driver initialization failed with "
1259                  "errno=%d\n", ret);
1260         return ret;
1261 }
1262
1263 static void __init css_bus_cleanup(void)
1264 {
1265         struct channel_subsystem *css;
1266
1267         for_each_css(css) {
1268                 device_unregister(&css->pseudo_subchannel->dev);
1269                 device_unregister(&css->device);
1270         }
1271         bus_unregister(&css_bus_type);
1272         crw_unregister_handler(CRW_RSC_SCH);
1273         idset_free(slow_subchannel_set);
1274         chsc_init_cleanup();
1275         isc_unregister(IO_SCH_ISC);
1276 }
1277
1278 static int __init channel_subsystem_init(void)
1279 {
1280         int ret;
1281
1282         ret = css_bus_init();
1283         if (ret)
1284                 return ret;
1285         cio_work_q = create_singlethread_workqueue("cio");
1286         if (!cio_work_q) {
1287                 ret = -ENOMEM;
1288                 goto out_bus;
1289         }
1290         ret = io_subchannel_init();
1291         if (ret)
1292                 goto out_wq;
1293
1294         /* Register subchannels which are already in use. */
1295         cio_register_early_subchannels();
1296         /* Start initial subchannel evaluation. */
1297         css_schedule_eval_all();
1298
1299         return ret;
1300 out_wq:
1301         destroy_workqueue(cio_work_q);
1302 out_bus:
1303         css_bus_cleanup();
1304         return ret;
1305 }
1306 subsys_initcall(channel_subsystem_init);
1307
1308 static int css_settle(struct device_driver *drv, void *unused)
1309 {
1310         struct css_driver *cssdrv = to_cssdriver(drv);
1311
1312         if (cssdrv->settle)
1313                 return cssdrv->settle();
1314         return 0;
1315 }
1316
1317 int css_complete_work(void)
1318 {
1319         int ret;
1320
1321         /* Wait for the evaluation of subchannels to finish. */
1322         ret = wait_event_interruptible(css_eval_wq,
1323                                        atomic_read(&css_eval_scheduled) == 0);
1324         if (ret)
1325                 return -EINTR;
1326         flush_workqueue(cio_work_q);
1327         /* Wait for the subchannel type specific initialization to finish */
1328         return bus_for_each_drv(&css_bus_type, NULL, NULL, css_settle);
1329 }
1330
1331
1332 /*
1333  * Wait for the initialization of devices to finish, to make sure we are
1334  * done with our setup if the search for the root device starts.
1335  */
1336 static int __init channel_subsystem_init_sync(void)
1337 {
1338         css_complete_work();
1339         return 0;
1340 }
1341 subsys_initcall_sync(channel_subsystem_init_sync);
1342
1343 void channel_subsystem_reinit(void)
1344 {
1345         struct channel_path *chp;
1346         struct chp_id chpid;
1347
1348         chsc_enable_facility(CHSC_SDA_OC_MSS);
1349         chp_id_for_each(&chpid) {
1350                 chp = chpid_to_chp(chpid);
1351                 if (chp)
1352                         chp_update_desc(chp);
1353         }
1354         cmf_reactivate();
1355 }
1356
1357 #ifdef CONFIG_PROC_FS
1358 static ssize_t cio_settle_write(struct file *file, const char __user *buf,
1359                                 size_t count, loff_t *ppos)
1360 {
1361         int ret;
1362
1363         /* Handle pending CRW's. */
1364         crw_wait_for_channel_report();
1365         ret = css_complete_work();
1366
1367         return ret ? ret : count;
1368 }
1369
1370 static const struct file_operations cio_settle_proc_fops = {
1371         .open = nonseekable_open,
1372         .write = cio_settle_write,
1373         .llseek = no_llseek,
1374 };
1375
1376 static int __init cio_settle_init(void)
1377 {
1378         struct proc_dir_entry *entry;
1379
1380         entry = proc_create("cio_settle", S_IWUSR, NULL,
1381                             &cio_settle_proc_fops);
1382         if (!entry)
1383                 return -ENOMEM;
1384         return 0;
1385 }
1386 device_initcall(cio_settle_init);
1387 #endif /*CONFIG_PROC_FS*/
1388
1389 int sch_is_pseudo_sch(struct subchannel *sch)
1390 {
1391         return sch == to_css(sch->dev.parent)->pseudo_subchannel;
1392 }
1393
1394 static int css_bus_match(struct device *dev, struct device_driver *drv)
1395 {
1396         struct subchannel *sch = to_subchannel(dev);
1397         struct css_driver *driver = to_cssdriver(drv);
1398         struct css_device_id *id;
1399
1400         /* When driver_override is set, only bind to the matching driver */
1401         if (sch->driver_override && strcmp(sch->driver_override, drv->name))
1402                 return 0;
1403
1404         for (id = driver->subchannel_type; id->match_flags; id++) {
1405                 if (sch->st == id->type)
1406                         return 1;
1407         }
1408
1409         return 0;
1410 }
1411
1412 static int css_probe(struct device *dev)
1413 {
1414         struct subchannel *sch;
1415         int ret;
1416
1417         sch = to_subchannel(dev);
1418         sch->driver = to_cssdriver(dev->driver);
1419         ret = sch->driver->probe ? sch->driver->probe(sch) : 0;
1420         if (ret)
1421                 sch->driver = NULL;
1422         return ret;
1423 }
1424
1425 static int css_remove(struct device *dev)
1426 {
1427         struct subchannel *sch;
1428         int ret;
1429
1430         sch = to_subchannel(dev);
1431         ret = sch->driver->remove ? sch->driver->remove(sch) : 0;
1432         sch->driver = NULL;
1433         return ret;
1434 }
1435
1436 static void css_shutdown(struct device *dev)
1437 {
1438         struct subchannel *sch;
1439
1440         sch = to_subchannel(dev);
1441         if (sch->driver && sch->driver->shutdown)
1442                 sch->driver->shutdown(sch);
1443 }
1444
1445 static int css_uevent(struct device *dev, struct kobj_uevent_env *env)
1446 {
1447         struct subchannel *sch = to_subchannel(dev);
1448         int ret;
1449
1450         ret = add_uevent_var(env, "ST=%01X", sch->st);
1451         if (ret)
1452                 return ret;
1453         ret = add_uevent_var(env, "MODALIAS=css:t%01X", sch->st);
1454         return ret;
1455 }
1456
1457 static int css_pm_prepare(struct device *dev)
1458 {
1459         struct subchannel *sch = to_subchannel(dev);
1460         struct css_driver *drv;
1461
1462         if (mutex_is_locked(&sch->reg_mutex))
1463                 return -EAGAIN;
1464         if (!sch->dev.driver)
1465                 return 0;
1466         drv = to_cssdriver(sch->dev.driver);
1467         /* Notify drivers that they may not register children. */
1468         return drv->prepare ? drv->prepare(sch) : 0;
1469 }
1470
1471 static void css_pm_complete(struct device *dev)
1472 {
1473         struct subchannel *sch = to_subchannel(dev);
1474         struct css_driver *drv;
1475
1476         if (!sch->dev.driver)
1477                 return;
1478         drv = to_cssdriver(sch->dev.driver);
1479         if (drv->complete)
1480                 drv->complete(sch);
1481 }
1482
1483 static int css_pm_freeze(struct device *dev)
1484 {
1485         struct subchannel *sch = to_subchannel(dev);
1486         struct css_driver *drv;
1487
1488         if (!sch->dev.driver)
1489                 return 0;
1490         drv = to_cssdriver(sch->dev.driver);
1491         return drv->freeze ? drv->freeze(sch) : 0;
1492 }
1493
1494 static int css_pm_thaw(struct device *dev)
1495 {
1496         struct subchannel *sch = to_subchannel(dev);
1497         struct css_driver *drv;
1498
1499         if (!sch->dev.driver)
1500                 return 0;
1501         drv = to_cssdriver(sch->dev.driver);
1502         return drv->thaw ? drv->thaw(sch) : 0;
1503 }
1504
1505 static int css_pm_restore(struct device *dev)
1506 {
1507         struct subchannel *sch = to_subchannel(dev);
1508         struct css_driver *drv;
1509
1510         css_update_ssd_info(sch);
1511         if (!sch->dev.driver)
1512                 return 0;
1513         drv = to_cssdriver(sch->dev.driver);
1514         return drv->restore ? drv->restore(sch) : 0;
1515 }
1516
1517 static const struct dev_pm_ops css_pm_ops = {
1518         .prepare = css_pm_prepare,
1519         .complete = css_pm_complete,
1520         .freeze = css_pm_freeze,
1521         .thaw = css_pm_thaw,
1522         .restore = css_pm_restore,
1523 };
1524
1525 static struct bus_type css_bus_type = {
1526         .name     = "css",
1527         .match    = css_bus_match,
1528         .probe    = css_probe,
1529         .remove   = css_remove,
1530         .shutdown = css_shutdown,
1531         .uevent   = css_uevent,
1532         .pm = &css_pm_ops,
1533 };
1534
1535 /**
1536  * css_driver_register - register a css driver
1537  * @cdrv: css driver to register
1538  *
1539  * This is mainly a wrapper around driver_register that sets name
1540  * and bus_type in the embedded struct device_driver correctly.
1541  */
1542 int css_driver_register(struct css_driver *cdrv)
1543 {
1544         cdrv->drv.bus = &css_bus_type;
1545         return driver_register(&cdrv->drv);
1546 }
1547 EXPORT_SYMBOL_GPL(css_driver_register);
1548
1549 /**
1550  * css_driver_unregister - unregister a css driver
1551  * @cdrv: css driver to unregister
1552  *
1553  * This is a wrapper around driver_unregister.
1554  */
1555 void css_driver_unregister(struct css_driver *cdrv)
1556 {
1557         driver_unregister(&cdrv->drv);
1558 }
1559 EXPORT_SYMBOL_GPL(css_driver_unregister);