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