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/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         sch->dev.dma_mask = &sch->dma_mask;
 229         device_initialize(&sch->dev);
 230         /*
 231          * The physical addresses for some of the dma structures that can
 232          * belong to a subchannel need to fit 31 bit width (e.g. ccw).
 233          */
 234         ret = dma_set_coherent_mask(&sch->dev, DMA_BIT_MASK(31));
 235         if (ret)
 236                 goto err;
 237         /*
 238          * But we don't have such restrictions imposed on the stuff that
 239          * is handled by the streaming API.
 240          */
 241         ret = dma_set_mask(&sch->dev, DMA_BIT_MASK(64));
 242         if (ret)
 243                 goto err;
 244
 245         return sch;
 246
 247 err:
 248         kfree(sch);
 249         return ERR_PTR(ret);
 250 }
 251
 252 static int css_sch_device_register(struct subchannel *sch)
 253 {
 254         int ret;
 255
 256         mutex_lock(&sch->reg_mutex);
 257         dev_set_name(&sch->dev, "0.%x.%04x", sch->schid.ssid,
 258                      sch->schid.sch_no);
 259         ret = device_add(&sch->dev);
 260         mutex_unlock(&sch->reg_mutex);
 261         return ret;
 262 }
 263
 264 /**
 265  * css_sch_device_unregister - unregister a subchannel
 266  * @sch: subchannel to be unregistered
 267  */
 268 void css_sch_device_unregister(struct subchannel *sch)
 269 {
 270         mutex_lock(&sch->reg_mutex);
 271         if (device_is_registered(&sch->dev))
 272                 device_unregister(&sch->dev);
 273         mutex_unlock(&sch->reg_mutex);
 274 }
 275 EXPORT_SYMBOL_GPL(css_sch_device_unregister);
 276
 277 static void ssd_from_pmcw(struct chsc_ssd_info *ssd, struct pmcw *pmcw)
 278 {
 279         int i;
 280         int mask;
 281
 282         memset(ssd, 0, sizeof(struct chsc_ssd_info));
 283         ssd->path_mask = pmcw->pim;
 284         for (i = 0; i < 8; i++) {
 285                 mask = 0x80 >> i;
 286                 if (pmcw->pim & mask) {
 287                         chp_id_init(&ssd->chpid[i]);
 288                         ssd->chpid[i].id = pmcw->chpid[i];
 289                 }
 290         }
 291 }
 292
 293 static void ssd_register_chpids(struct chsc_ssd_info *ssd)
 294 {
 295         int i;
 296         int mask;
 297
 298         for (i = 0; i < 8; i++) {
 299                 mask = 0x80 >> i;
 300                 if (ssd->path_mask & mask)
 301                         chp_new(ssd->chpid[i]);
 302         }
 303 }
 304
 305 void css_update_ssd_info(struct subchannel *sch)
 306 {
 307         int ret;
 308
 309         ret = chsc_get_ssd_info(sch->schid, &sch->ssd_info);
 310         if (ret)
 311                 ssd_from_pmcw(&sch->ssd_info, &sch->schib.pmcw);
 312
 313         ssd_register_chpids(&sch->ssd_info);
 314 }
 315
 316 static ssize_t type_show(struct device *dev, struct device_attribute *attr,
 317                          char *buf)
 318 {
 319         struct subchannel *sch = to_subchannel(dev);
 320
 321         return sprintf(buf, "%01x\n", sch->st);
 322 }
 323
 324 static DEVICE_ATTR_RO(type);
 325
 326 static ssize_t modalias_show(struct device *dev, struct device_attribute *attr,
 327                              char *buf)
 328 {
 329         struct subchannel *sch = to_subchannel(dev);
 330
 331         return sprintf(buf, "css:t%01X\n", sch->st);
 332 }
 333
 334 static DEVICE_ATTR_RO(modalias);
 335
 336 static ssize_t driver_override_store(struct device *dev,
 337                                      struct device_attribute *attr,
 338                                      const char *buf, size_t count)
 339 {
 340         struct subchannel *sch = to_subchannel(dev);
 341         char *driver_override, *old, *cp;
 342
 343         /* We need to keep extra room for a newline */
 344         if (count >= (PAGE_SIZE - 1))
 345                 return -EINVAL;
 346
 347         driver_override = kstrndup(buf, count, GFP_KERNEL);
 348         if (!driver_override)
 349                 return -ENOMEM;
 350
 351         cp = strchr(driver_override, '\n');
 352         if (cp)
 353                 *cp = '\0';
 354
 355         device_lock(dev);
 356         old = sch->driver_override;
 357         if (strlen(driver_override)) {
 358                 sch->driver_override = driver_override;
 359         } else {
 360                 kfree(driver_override);
 361                 sch->driver_override = NULL;
 362         }
 363         device_unlock(dev);
 364
 365         kfree(old);
 366
 367         return count;
 368 }
 369
 370 static ssize_t driver_override_show(struct device *dev,
 371                                     struct device_attribute *attr, char *buf)
 372 {
 373         struct subchannel *sch = to_subchannel(dev);
 374         ssize_t len;
 375
 376         device_lock(dev);
 377         len = snprintf(buf, PAGE_SIZE, "%s\n", sch->driver_override);
 378         device_unlock(dev);
 379         return len;
 380 }
 381 static DEVICE_ATTR_RW(driver_override);
 382
 383 static struct attribute *subch_attrs[] = {
 384         &dev_attr_type.attr,
 385         &dev_attr_modalias.attr,
 386         &dev_attr_driver_override.attr,
 387         NULL,
 388 };
 389
 390 static struct attribute_group subch_attr_group = {
 391         .attrs = subch_attrs,
 392 };
 393
 394 static const struct attribute_group *default_subch_attr_groups[] = {
 395         &subch_attr_group,
 396         NULL,
 397 };
 398
 399 static ssize_t chpids_show(struct device *dev,
 400                            struct device_attribute *attr,
 401                            char *buf)
 402 {
 403         struct subchannel *sch = to_subchannel(dev);
 404         struct chsc_ssd_info *ssd = &sch->ssd_info;
 405         ssize_t ret = 0;
 406         int mask;
 407         int chp;
 408
 409         for (chp = 0; chp < 8; chp++) {
 410                 mask = 0x80 >> chp;
 411                 if (ssd->path_mask & mask)
 412                         ret += sprintf(buf + ret, "%02x ", ssd->chpid[chp].id);
 413                 else
 414                         ret += sprintf(buf + ret, "00 ");
 415         }
 416         ret += sprintf(buf + ret, "\n");
 417         return ret;
 418 }
 419 static DEVICE_ATTR_RO(chpids);
 420
 421 static ssize_t pimpampom_show(struct device *dev,
 422                               struct device_attribute *attr,
 423                               char *buf)
 424 {
 425         struct subchannel *sch = to_subchannel(dev);
 426         struct pmcw *pmcw = &sch->schib.pmcw;
 427
 428         return sprintf(buf, "%02x %02x %02x\n",
 429                        pmcw->pim, pmcw->pam, pmcw->pom);
 430 }
 431 static DEVICE_ATTR_RO(pimpampom);
 432
 433 static struct attribute *io_subchannel_type_attrs[] = {
 434         &dev_attr_chpids.attr,
 435         &dev_attr_pimpampom.attr,
 436         NULL,
 437 };
 438 ATTRIBUTE_GROUPS(io_subchannel_type);
 439
 440 static const struct device_type io_subchannel_type = {
 441         .groups = io_subchannel_type_groups,
 442 };
 443
 444 int css_register_subchannel(struct subchannel *sch)
 445 {
 446         int ret;
 447
 448         /* Initialize the subchannel structure */
 449         sch->dev.parent = &channel_subsystems[0]->device;
 450         sch->dev.bus = &css_bus_type;
 451         sch->dev.groups = default_subch_attr_groups;
 452
 453         if (sch->st == SUBCHANNEL_TYPE_IO)
 454                 sch->dev.type = &io_subchannel_type;
 455
 456         /*
 457          * We don't want to generate uevents for I/O subchannels that don't
 458          * have a working ccw device behind them since they will be
 459          * unregistered before they can be used anyway, so we delay the add
 460          * uevent until after device recognition was successful.
 461          * Note that we suppress the uevent for all subchannel types;
 462          * the subchannel driver can decide itself when it wants to inform
 463          * userspace of its existence.
 464          */
 465         dev_set_uevent_suppress(&sch->dev, 1);
 466         css_update_ssd_info(sch);
 467         /* make it known to the system */
 468         ret = css_sch_device_register(sch);
 469         if (ret) {
 470                 CIO_MSG_EVENT(0, "Could not register sch 0.%x.%04x: %d\n",
 471                               sch->schid.ssid, sch->schid.sch_no, ret);
 472                 return ret;
 473         }
 474         if (!sch->driver) {
 475                 /*
 476                  * No driver matched. Generate the uevent now so that
 477                  * a fitting driver module may be loaded based on the
 478                  * modalias.
 479                  */
 480                 dev_set_uevent_suppress(&sch->dev, 0);
 481                 kobject_uevent(&sch->dev.kobj, KOBJ_ADD);
 482         }
 483         return ret;
 484 }
 485
 486 static int css_probe_device(struct subchannel_id schid, struct schib *schib)
 487 {
 488         struct subchannel *sch;
 489         int ret;
 490
 491         sch = css_alloc_subchannel(schid, schib);
 492         if (IS_ERR(sch))
 493                 return PTR_ERR(sch);
 494
 495         ret = css_register_subchannel(sch);
 496         if (ret)
 497                 put_device(&sch->dev);
 498
 499         return ret;
 500 }
 501
 502 static int
 503 check_subchannel(struct device *dev, const void *data)
 504 {
 505         struct subchannel *sch;
 506         struct subchannel_id *schid = (void *)data;
 507
 508         sch = to_subchannel(dev);
 509         return schid_equal(&sch->schid, schid);
 510 }
 511
 512 struct subchannel *
 513 get_subchannel_by_schid(struct subchannel_id schid)
 514 {
 515         struct device *dev;
 516
 517         dev = bus_find_device(&css_bus_type, NULL,
 518                               &schid, check_subchannel);
 519
 520         return dev ? to_subchannel(dev) : NULL;
 521 }
 522
 523 /**
 524  * css_sch_is_valid() - check if a subchannel is valid
 525  * @schib: subchannel information block for the subchannel
 526  */
 527 int css_sch_is_valid(struct schib *schib)
 528 {
 529         if ((schib->pmcw.st == SUBCHANNEL_TYPE_IO) && !schib->pmcw.dnv)
 530                 return 0;
 531         if ((schib->pmcw.st == SUBCHANNEL_TYPE_MSG) && !schib->pmcw.w)
 532                 return 0;
 533         return 1;
 534 }
 535 EXPORT_SYMBOL_GPL(css_sch_is_valid);
 536
 537 static int css_evaluate_new_subchannel(struct subchannel_id schid, int slow)
 538 {
 539         struct schib schib;
 540         int ccode;
 541
 542         if (!slow) {
 543                 /* Will be done on the slow path. */
 544                 return -EAGAIN;
 545         }
 546         /*
 547          * The first subchannel that is not-operational (ccode==3)
 548          * indicates that there aren't any more devices available.
 549          * If stsch gets an exception, it means the current subchannel set
 550          * is not valid.
 551          */
 552         ccode = stsch(schid, &schib);
 553         if (ccode)
 554                 return (ccode == 3) ? -ENXIO : ccode;
 555
 556         return css_probe_device(schid, &schib);
 557 }
 558
 559 static int css_evaluate_known_subchannel(struct subchannel *sch, int slow)
 560 {
 561         int ret = 0;
 562
 563         if (sch->driver) {
 564                 if (sch->driver->sch_event)
 565                         ret = sch->driver->sch_event(sch, slow);
 566                 else
 567                         dev_dbg(&sch->dev,
 568                                 "Got subchannel machine check but "
 569                                 "no sch_event handler provided.\n");
 570         }
 571         if (ret != 0 && ret != -EAGAIN) {
 572                 CIO_MSG_EVENT(2, "eval: sch 0.%x.%04x, rc=%d\n",
 573                               sch->schid.ssid, sch->schid.sch_no, ret);
 574         }
 575         return ret;
 576 }
 577
 578 static void css_evaluate_subchannel(struct subchannel_id schid, int slow)
 579 {
 580         struct subchannel *sch;
 581         int ret;
 582
 583         sch = get_subchannel_by_schid(schid);
 584         if (sch) {
 585                 ret = css_evaluate_known_subchannel(sch, slow);
 586                 put_device(&sch->dev);
 587         } else
 588                 ret = css_evaluate_new_subchannel(schid, slow);
 589         if (ret == -EAGAIN)
 590                 css_schedule_eval(schid);
 591 }
 592
 593 /**
 594  * css_sched_sch_todo - schedule a subchannel operation
 595  * @sch: subchannel
 596  * @todo: todo
 597  *
 598  * Schedule the operation identified by @todo to be performed on the slow path
 599  * workqueue. Do nothing if another operation with higher priority is already
 600  * scheduled. Needs to be called with subchannel lock held.
 601  */
 602 void css_sched_sch_todo(struct subchannel *sch, enum sch_todo todo)
 603 {
 604         CIO_MSG_EVENT(4, "sch_todo: sched sch=0.%x.%04x todo=%d\n",
 605                       sch->schid.ssid, sch->schid.sch_no, todo);
 606         if (sch->todo >= todo)
 607                 return;
 608         /* Get workqueue ref. */
 609         if (!get_device(&sch->dev))
 610                 return;
 611         sch->todo = todo;
 612         if (!queue_work(cio_work_q, &sch->todo_work)) {
 613                 /* Already queued, release workqueue ref. */
 614                 put_device(&sch->dev);
 615         }
 616 }
 617 EXPORT_SYMBOL_GPL(css_sched_sch_todo);
 618
 619 static void css_sch_todo(struct work_struct *work)
 620 {
 621         struct subchannel *sch;
 622         enum sch_todo todo;
 623         int ret;
 624
 625         sch = container_of(work, struct subchannel, todo_work);
 626         /* Find out todo. */
 627         spin_lock_irq(sch->lock);
 628         todo = sch->todo;
 629         CIO_MSG_EVENT(4, "sch_todo: sch=0.%x.%04x, todo=%d\n", sch->schid.ssid,
 630                       sch->schid.sch_no, todo);
 631         sch->todo = SCH_TODO_NOTHING;
 632         spin_unlock_irq(sch->lock);
 633         /* Perform todo. */
 634         switch (todo) {
 635         case SCH_TODO_NOTHING:
 636                 break;
 637         case SCH_TODO_EVAL:
 638                 ret = css_evaluate_known_subchannel(sch, 1);
 639                 if (ret == -EAGAIN) {
 640                         spin_lock_irq(sch->lock);
 641                         css_sched_sch_todo(sch, todo);
 642                         spin_unlock_irq(sch->lock);
 643                 }
 644                 break;
 645         case SCH_TODO_UNREG:
 646                 css_sch_device_unregister(sch);
 647                 break;
 648         }
 649         /* Release workqueue ref. */
 650         put_device(&sch->dev);
 651 }
 652
 653 static struct idset *slow_subchannel_set;
 654 static spinlock_t slow_subchannel_lock;
 655 static wait_queue_head_t css_eval_wq;
 656 static atomic_t css_eval_scheduled;
 657
 658 static int __init slow_subchannel_init(void)
 659 {
 660         spin_lock_init(&slow_subchannel_lock);
 661         atomic_set(&css_eval_scheduled, 0);
 662         init_waitqueue_head(&css_eval_wq);
 663         slow_subchannel_set = idset_sch_new();
 664         if (!slow_subchannel_set) {
 665                 CIO_MSG_EVENT(0, "could not allocate slow subchannel set\n");
 666                 return -ENOMEM;
 667         }
 668         return 0;
 669 }
 670
 671 static int slow_eval_known_fn(struct subchannel *sch, void *data)
 672 {
 673         int eval;
 674         int rc;
 675
 676         spin_lock_irq(&slow_subchannel_lock);
 677         eval = idset_sch_contains(slow_subchannel_set, sch->schid);
 678         idset_sch_del(slow_subchannel_set, sch->schid);
 679         spin_unlock_irq(&slow_subchannel_lock);
 680         if (eval) {
 681                 rc = css_evaluate_known_subchannel(sch, 1);
 682                 if (rc == -EAGAIN)
 683                         css_schedule_eval(sch->schid);
 684                 /*
 685                  * The loop might take long time for platforms with lots of
 686                  * known devices. Allow scheduling here.
 687                  */
 688                 cond_resched();
 689         }
 690         return 0;
 691 }
 692
 693 static int slow_eval_unknown_fn(struct subchannel_id schid, void *data)
 694 {
 695         int eval;
 696         int rc = 0;
 697
 698         spin_lock_irq(&slow_subchannel_lock);
 699         eval = idset_sch_contains(slow_subchannel_set, schid);
 700         idset_sch_del(slow_subchannel_set, schid);
 701         spin_unlock_irq(&slow_subchannel_lock);
 702         if (eval) {
 703                 rc = css_evaluate_new_subchannel(schid, 1);
 704                 switch (rc) {
 705                 case -EAGAIN:
 706                         css_schedule_eval(schid);
 707                         rc = 0;
 708                         break;
 709                 case -ENXIO:
 710                 case -ENOMEM:
 711                 case -EIO:
 712                         /* These should abort looping */
 713                         spin_lock_irq(&slow_subchannel_lock);
 714                         idset_sch_del_subseq(slow_subchannel_set, schid);
 715                         spin_unlock_irq(&slow_subchannel_lock);
 716                         break;
 717                 default:
 718                         rc = 0;
 719                 }
 720                 /* Allow scheduling here since the containing loop might
 721                  * take a while.  */
 722                 cond_resched();
 723         }
 724         return rc;
 725 }
 726
 727 static void css_slow_path_func(struct work_struct *unused)
 728 {
 729         unsigned long flags;
 730
 731         CIO_TRACE_EVENT(4, "slowpath");
 732         for_each_subchannel_staged(slow_eval_known_fn, slow_eval_unknown_fn,
 733                                    NULL);
 734         spin_lock_irqsave(&slow_subchannel_lock, flags);
 735         if (idset_is_empty(slow_subchannel_set)) {
 736                 atomic_set(&css_eval_scheduled, 0);
 737                 wake_up(&css_eval_wq);
 738         }
 739         spin_unlock_irqrestore(&slow_subchannel_lock, flags);
 740 }
 741
 742 static DECLARE_DELAYED_WORK(slow_path_work, css_slow_path_func);
 743 struct workqueue_struct *cio_work_q;
 744
 745 void css_schedule_eval(struct subchannel_id schid)
 746 {
 747         unsigned long flags;
 748
 749         spin_lock_irqsave(&slow_subchannel_lock, flags);
 750         idset_sch_add(slow_subchannel_set, schid);
 751         atomic_set(&css_eval_scheduled, 1);
 752         queue_delayed_work(cio_work_q, &slow_path_work, 0);
 753         spin_unlock_irqrestore(&slow_subchannel_lock, flags);
 754 }
 755
 756 void css_schedule_eval_all(void)
 757 {
 758         unsigned long flags;
 759
 760         spin_lock_irqsave(&slow_subchannel_lock, flags);
 761         idset_fill(slow_subchannel_set);
 762         atomic_set(&css_eval_scheduled, 1);
 763         queue_delayed_work(cio_work_q, &slow_path_work, 0);
 764         spin_unlock_irqrestore(&slow_subchannel_lock, flags);
 765 }
 766
 767 static int __unset_registered(struct device *dev, void *data)
 768 {
 769         struct idset *set = data;
 770         struct subchannel *sch = to_subchannel(dev);
 771
 772         idset_sch_del(set, sch->schid);
 773         return 0;
 774 }
 775
 776 void css_schedule_eval_all_unreg(unsigned long delay)
 777 {
 778         unsigned long flags;
 779         struct idset *unreg_set;
 780
 781         /* Find unregistered subchannels. */
 782         unreg_set = idset_sch_new();
 783         if (!unreg_set) {
 784                 /* Fallback. */
 785                 css_schedule_eval_all();
 786                 return;
 787         }
 788         idset_fill(unreg_set);
 789         bus_for_each_dev(&css_bus_type, NULL, unreg_set, __unset_registered);
 790         /* Apply to slow_subchannel_set. */
 791         spin_lock_irqsave(&slow_subchannel_lock, flags);
 792         idset_add_set(slow_subchannel_set, unreg_set);
 793         atomic_set(&css_eval_scheduled, 1);
 794         queue_delayed_work(cio_work_q, &slow_path_work, delay);
 795         spin_unlock_irqrestore(&slow_subchannel_lock, flags);
 796         idset_free(unreg_set);
 797 }
 798
 799 void css_wait_for_slow_path(void)
 800 {
 801         flush_workqueue(cio_work_q);
 802 }
 803
 804 /* Schedule reprobing of all unregistered subchannels. */
 805 void css_schedule_reprobe(void)
 806 {
 807         /* Schedule with a delay to allow merging of subsequent calls. */
 808         css_schedule_eval_all_unreg(1 * HZ);
 809 }
 810 EXPORT_SYMBOL_GPL(css_schedule_reprobe);
 811
 812 /*
 813  * Called from the machine check handler for subchannel report words.
 814  */
 815 static void css_process_crw(struct crw *crw0, struct crw *crw1, int overflow)
 816 {
 817         struct subchannel_id mchk_schid;
 818         struct subchannel *sch;
 819
 820         if (overflow) {
 821                 css_schedule_eval_all();
 822                 return;
 823         }
 824         CIO_CRW_EVENT(2, "CRW0 reports slct=%d, oflw=%d, "
 825                       "chn=%d, rsc=%X, anc=%d, erc=%X, rsid=%X\n",
 826                       crw0->slct, crw0->oflw, crw0->chn, crw0->rsc, crw0->anc,
 827                       crw0->erc, crw0->rsid);
 828         if (crw1)
 829                 CIO_CRW_EVENT(2, "CRW1 reports slct=%d, oflw=%d, "
 830                               "chn=%d, rsc=%X, anc=%d, erc=%X, rsid=%X\n",
 831                               crw1->slct, crw1->oflw, crw1->chn, crw1->rsc,
 832                               crw1->anc, crw1->erc, crw1->rsid);
 833         init_subchannel_id(&mchk_schid);
 834         mchk_schid.sch_no = crw0->rsid;
 835         if (crw1)
 836                 mchk_schid.ssid = (crw1->rsid >> 4) & 3;
 837
 838         if (crw0->erc == CRW_ERC_PMOD) {
 839                 sch = get_subchannel_by_schid(mchk_schid);
 840                 if (sch) {
 841                         css_update_ssd_info(sch);
 842                         put_device(&sch->dev);
 843                 }
 844         }
 845         /*
 846          * Since we are always presented with IPI in the CRW, we have to
 847          * use stsch() to find out if the subchannel in question has come
 848          * or gone.
 849          */
 850         css_evaluate_subchannel(mchk_schid, 0);
 851 }
 852
 853 static void __init
 854 css_generate_pgid(struct channel_subsystem *css, u32 tod_high)
 855 {
 856         struct cpuid cpu_id;
 857
 858         if (css_general_characteristics.mcss) {
 859                 css->global_pgid.pgid_high.ext_cssid.version = 0x80;
 860                 css->global_pgid.pgid_high.ext_cssid.cssid =
 861                         css->id_valid ? css->cssid : 0;
 862         } else {
 863                 css->global_pgid.pgid_high.cpu_addr = stap();
 864         }
 865         get_cpu_id(&cpu_id);
 866         css->global_pgid.cpu_id = cpu_id.ident;
 867         css->global_pgid.cpu_model = cpu_id.machine;
 868         css->global_pgid.tod_high = tod_high;
 869 }
 870
 871 static void channel_subsystem_release(struct device *dev)
 872 {
 873         struct channel_subsystem *css = to_css(dev);
 874
 875         mutex_destroy(&css->mutex);
 876         kfree(css);
 877 }
 878
 879 static ssize_t real_cssid_show(struct device *dev, struct device_attribute *a,
 880                                char *buf)
 881 {
 882         struct channel_subsystem *css = to_css(dev);
 883
 884         if (!css->id_valid)
 885                 return -EINVAL;
 886
 887         return sprintf(buf, "%x\n", css->cssid);
 888 }
 889 static DEVICE_ATTR_RO(real_cssid);
 890
 891 static ssize_t cm_enable_show(struct device *dev, struct device_attribute *a,
 892                               char *buf)
 893 {
 894         struct channel_subsystem *css = to_css(dev);
 895         int ret;
 896
 897         mutex_lock(&css->mutex);
 898         ret = sprintf(buf, "%x\n", css->cm_enabled);
 899         mutex_unlock(&css->mutex);
 900         return ret;
 901 }
 902
 903 static ssize_t cm_enable_store(struct device *dev, struct device_attribute *a,
 904                                const char *buf, size_t count)
 905 {
 906         struct channel_subsystem *css = to_css(dev);
 907         unsigned long val;
 908         int ret;
 909
 910         ret = kstrtoul(buf, 16, &val);
 911         if (ret)
 912                 return ret;
 913         mutex_lock(&css->mutex);
 914         switch (val) {
 915         case 0:
 916                 ret = css->cm_enabled ? chsc_secm(css, 0) : 0;
 917                 break;
 918         case 1:
 919                 ret = css->cm_enabled ? 0 : chsc_secm(css, 1);
 920                 break;
 921         default:
 922                 ret = -EINVAL;
 923         }
 924         mutex_unlock(&css->mutex);
 925         return ret < 0 ? ret : count;
 926 }
 927 static DEVICE_ATTR_RW(cm_enable);
 928
 929 static umode_t cm_enable_mode(struct kobject *kobj, struct attribute *attr,
 930                               int index)
 931 {
 932         return css_chsc_characteristics.secm ? attr->mode : 0;
 933 }
 934
 935 static struct attribute *cssdev_attrs[] = {
 936         &dev_attr_real_cssid.attr,
 937         NULL,
 938 };
 939
 940 static struct attribute_group cssdev_attr_group = {
 941         .attrs = cssdev_attrs,
 942 };
 943
 944 static struct attribute *cssdev_cm_attrs[] = {
 945         &dev_attr_cm_enable.attr,
 946         NULL,
 947 };
 948
 949 static struct attribute_group cssdev_cm_attr_group = {
 950         .attrs = cssdev_cm_attrs,
 951         .is_visible = cm_enable_mode,
 952 };
 953
 954 static const struct attribute_group *cssdev_attr_groups[] = {
 955         &cssdev_attr_group,
 956         &cssdev_cm_attr_group,
 957         NULL,
 958 };
 959
 960 static int __init setup_css(int nr)
 961 {
 962         struct channel_subsystem *css;
 963         int ret;
 964
 965         css = kzalloc(sizeof(*css), GFP_KERNEL);
 966         if (!css)
 967                 return -ENOMEM;
 968
 969         channel_subsystems[nr] = css;
 970         dev_set_name(&css->device, "css%x", nr);
 971         css->device.groups = cssdev_attr_groups;
 972         css->device.release = channel_subsystem_release;
 973         /*
 974          * We currently allocate notifier bits with this (using
 975          * css->device as the device argument with the DMA API)
 976          * and are fine with 64 bit addresses.
 977          */
 978         ret = dma_coerce_mask_and_coherent(&css->device, DMA_BIT_MASK(64));
 979         if (ret) {
 980                 kfree(css);
 981                 goto out_err;
 982         }
 983
 984         mutex_init(&css->mutex);
 985         ret = chsc_get_cssid_iid(nr, &css->cssid, &css->iid);
 986         if (!ret) {
 987                 css->id_valid = true;
 988                 pr_info("Partition identifier %01x.%01x\n", css->cssid,
 989                         css->iid);
 990         }
 991         css_generate_pgid(css, (u32) (get_tod_clock() >> 32));
 992
 993         ret = device_register(&css->device);
 994         if (ret) {
 995                 put_device(&css->device);
 996                 goto out_err;
 997         }
 998
 999         css->pseudo_subchannel = kzalloc(sizeof(*css->pseudo_subchannel),
1000                                          GFP_KERNEL);
1001         if (!css->pseudo_subchannel) {
1002                 device_unregister(&css->device);
1003                 ret = -ENOMEM;
1004                 goto out_err;
1005         }
1006
1007         css->pseudo_subchannel->dev.parent = &css->device;
1008         css->pseudo_subchannel->dev.release = css_subchannel_release;
1009         mutex_init(&css->pseudo_subchannel->reg_mutex);
1010         ret = css_sch_create_locks(css->pseudo_subchannel);
1011         if (ret) {
1012                 kfree(css->pseudo_subchannel);
1013                 device_unregister(&css->device);
1014                 goto out_err;
1015         }
1016
1017         dev_set_name(&css->pseudo_subchannel->dev, "defunct");
1018         ret = device_register(&css->pseudo_subchannel->dev);
1019         if (ret) {
1020                 put_device(&css->pseudo_subchannel->dev);
1021                 device_unregister(&css->device);
1022                 goto out_err;
1023         }
1024
1025         return ret;
1026 out_err:
1027         channel_subsystems[nr] = NULL;
1028         return ret;
1029 }
1030
1031 static int css_reboot_event(struct notifier_block *this,
1032                             unsigned long event,
1033                             void *ptr)
1034 {
1035         struct channel_subsystem *css;
1036         int ret;
1037
1038         ret = NOTIFY_DONE;
1039         for_each_css(css) {
1040                 mutex_lock(&css->mutex);
1041                 if (css->cm_enabled)
1042                         if (chsc_secm(css, 0))
1043                                 ret = NOTIFY_BAD;
1044                 mutex_unlock(&css->mutex);
1045         }
1046
1047         return ret;
1048 }
1049
1050 static struct notifier_block css_reboot_notifier = {
1051         .notifier_call = css_reboot_event,
1052 };
1053
1054 #define  CIO_DMA_GFP (GFP_KERNEL | __GFP_ZERO)
1055 static struct gen_pool *cio_dma_pool;
1056
1057 /* Currently cio supports only a single css */
1058 struct device *cio_get_dma_css_dev(void)
1059 {
1060         return &channel_subsystems[0]->device;
1061 }
1062
1063 struct gen_pool *cio_gp_dma_create(struct device *dma_dev, int nr_pages)
1064 {
1065         struct gen_pool *gp_dma;
1066         void *cpu_addr;
1067         dma_addr_t dma_addr;
1068         int i;
1069
1070         gp_dma = gen_pool_create(3, -1);
1071         if (!gp_dma)
1072                 return NULL;
1073         for (i = 0; i < nr_pages; ++i) {
1074                 cpu_addr = dma_alloc_coherent(dma_dev, PAGE_SIZE, &dma_addr,
1075                                               CIO_DMA_GFP);
1076                 if (!cpu_addr)
1077                         return gp_dma;
1078                 gen_pool_add_virt(gp_dma, (unsigned long) cpu_addr,
1079                                   dma_addr, PAGE_SIZE, -1);
1080         }
1081         return gp_dma;
1082 }
1083
1084 static void __gp_dma_free_dma(struct gen_pool *pool,
1085                               struct gen_pool_chunk *chunk, void *data)
1086 {
1087         size_t chunk_size = chunk->end_addr - chunk->start_addr + 1;
1088
1089         dma_free_coherent((struct device *) data, chunk_size,
1090                          (void *) chunk->start_addr,
1091                          (dma_addr_t) chunk->phys_addr);
1092 }
1093
1094 void cio_gp_dma_destroy(struct gen_pool *gp_dma, struct device *dma_dev)
1095 {
1096         if (!gp_dma)
1097                 return;
1098         /* this is quite ugly but no better idea */
1099         gen_pool_for_each_chunk(gp_dma, __gp_dma_free_dma, dma_dev);
1100         gen_pool_destroy(gp_dma);
1101 }
1102
1103 static int cio_dma_pool_init(void)
1104 {
1105         /* No need to free up the resources: compiled in */
1106         cio_dma_pool = cio_gp_dma_create(cio_get_dma_css_dev(), 1);
1107         if (!cio_dma_pool)
1108                 return -ENOMEM;
1109         return 0;
1110 }
1111
1112 void *cio_gp_dma_zalloc(struct gen_pool *gp_dma, struct device *dma_dev,
1113                         size_t size)
1114 {
1115         dma_addr_t dma_addr;
1116         unsigned long addr;
1117         size_t chunk_size;
1118
1119         if (!gp_dma)
1120                 return NULL;
1121         addr = gen_pool_alloc(gp_dma, size);
1122         while (!addr) {
1123                 chunk_size = round_up(size, PAGE_SIZE);
1124                 addr = (unsigned long) dma_alloc_coherent(dma_dev,
1125                                          chunk_size, &dma_addr, CIO_DMA_GFP);
1126                 if (!addr)
1127                         return NULL;
1128                 gen_pool_add_virt(gp_dma, addr, dma_addr, chunk_size, -1);
1129                 addr = gen_pool_alloc(gp_dma, size);
1130         }
1131         return (void *) addr;
1132 }
1133
1134 void cio_gp_dma_free(struct gen_pool *gp_dma, void *cpu_addr, size_t size)
1135 {
1136         if (!cpu_addr)
1137                 return;
1138         memset(cpu_addr, 0, size);
1139         gen_pool_free(gp_dma, (unsigned long) cpu_addr, size);
1140 }
1141
1142 /*
1143  * Allocate dma memory from the css global pool. Intended for memory not
1144  * specific to any single device within the css. The allocated memory
1145  * is not guaranteed to be 31-bit addressable.
1146  *
1147  * Caution: Not suitable for early stuff like console.
1148  */
1149 void *cio_dma_zalloc(size_t size)
1150 {
1151         return cio_gp_dma_zalloc(cio_dma_pool, cio_get_dma_css_dev(), size);
1152 }
1153
1154 void cio_dma_free(void *cpu_addr, size_t size)
1155 {
1156         cio_gp_dma_free(cio_dma_pool, cpu_addr, size);
1157 }
1158
1159 /*
1160  * Now that the driver core is running, we can setup our channel subsystem.
1161  * The struct subchannel's are created during probing.
1162  */
1163 static int __init css_bus_init(void)
1164 {
1165         int ret, i;
1166
1167         ret = chsc_init();
1168         if (ret)
1169                 return ret;
1170
1171         chsc_determine_css_characteristics();
1172         /* Try to enable MSS. */
1173         ret = chsc_enable_facility(CHSC_SDA_OC_MSS);
1174         if (ret)
1175                 max_ssid = 0;
1176         else /* Success. */
1177                 max_ssid = __MAX_SSID;
1178
1179         ret = slow_subchannel_init();
1180         if (ret)
1181                 goto out;
1182
1183         ret = crw_register_handler(CRW_RSC_SCH, css_process_crw);
1184         if (ret)
1185                 goto out;
1186
1187         if ((ret = bus_register(&css_bus_type)))
1188                 goto out;
1189
1190         /* Setup css structure. */
1191         for (i = 0; i <= MAX_CSS_IDX; i++) {
1192                 ret = setup_css(i);
1193                 if (ret)
1194                         goto out_unregister;
1195         }
1196         ret = register_reboot_notifier(&css_reboot_notifier);
1197         if (ret)
1198                 goto out_unregister;
1199         ret = cio_dma_pool_init();
1200         if (ret)
1201                 goto out_unregister_rn;
1202         airq_init();
1203         css_init_done = 1;
1204
1205         /* Enable default isc for I/O subchannels. */
1206         isc_register(IO_SCH_ISC);
1207
1208         return 0;
1209 out_unregister_rn:
1210         unregister_reboot_notifier(&css_reboot_notifier);
1211 out_unregister:
1212         while (i-- > 0) {
1213                 struct channel_subsystem *css = channel_subsystems[i];
1214                 device_unregister(&css->pseudo_subchannel->dev);
1215                 device_unregister(&css->device);
1216         }
1217         bus_unregister(&css_bus_type);
1218 out:
1219         crw_unregister_handler(CRW_RSC_SCH);
1220         idset_free(slow_subchannel_set);
1221         chsc_init_cleanup();
1222         pr_alert("The CSS device driver initialization failed with "
1223                  "errno=%d\n", ret);
1224         return ret;
1225 }
1226
1227 static void __init css_bus_cleanup(void)
1228 {
1229         struct channel_subsystem *css;
1230
1231         for_each_css(css) {
1232                 device_unregister(&css->pseudo_subchannel->dev);
1233                 device_unregister(&css->device);
1234         }
1235         bus_unregister(&css_bus_type);
1236         crw_unregister_handler(CRW_RSC_SCH);
1237         idset_free(slow_subchannel_set);
1238         chsc_init_cleanup();
1239         isc_unregister(IO_SCH_ISC);
1240 }
1241
1242 static int __init channel_subsystem_init(void)
1243 {
1244         int ret;
1245
1246         ret = css_bus_init();
1247         if (ret)
1248                 return ret;
1249         cio_work_q = create_singlethread_workqueue("cio");
1250         if (!cio_work_q) {
1251                 ret = -ENOMEM;
1252                 goto out_bus;
1253         }
1254         ret = io_subchannel_init();
1255         if (ret)
1256                 goto out_wq;
1257
1258         /* Register subchannels which are already in use. */
1259         cio_register_early_subchannels();
1260         /* Start initial subchannel evaluation. */
1261         css_schedule_eval_all();
1262
1263         return ret;
1264 out_wq:
1265         destroy_workqueue(cio_work_q);
1266 out_bus:
1267         css_bus_cleanup();
1268         return ret;
1269 }
1270 subsys_initcall(channel_subsystem_init);
1271
1272 static int css_settle(struct device_driver *drv, void *unused)
1273 {
1274         struct css_driver *cssdrv = to_cssdriver(drv);
1275
1276         if (cssdrv->settle)
1277                 return cssdrv->settle();
1278         return 0;
1279 }
1280
1281 int css_complete_work(void)
1282 {
1283         int ret;
1284
1285         /* Wait for the evaluation of subchannels to finish. */
1286         ret = wait_event_interruptible(css_eval_wq,
1287                                        atomic_read(&css_eval_scheduled) == 0);
1288         if (ret)
1289                 return -EINTR;
1290         flush_workqueue(cio_work_q);
1291         /* Wait for the subchannel type specific initialization to finish */
1292         return bus_for_each_drv(&css_bus_type, NULL, NULL, css_settle);
1293 }
1294
1295
1296 /*
1297  * Wait for the initialization of devices to finish, to make sure we are
1298  * done with our setup if the search for the root device starts.
1299  */
1300 static int __init channel_subsystem_init_sync(void)
1301 {
1302         css_complete_work();
1303         return 0;
1304 }
1305 subsys_initcall_sync(channel_subsystem_init_sync);
1306
1307 #ifdef CONFIG_PROC_FS
1308 static ssize_t cio_settle_write(struct file *file, const char __user *buf,
1309                                 size_t count, loff_t *ppos)
1310 {
1311         int ret;
1312
1313         /* Handle pending CRW's. */
1314         crw_wait_for_channel_report();
1315         ret = css_complete_work();
1316
1317         return ret ? ret : count;
1318 }
1319
1320 static const struct proc_ops cio_settle_proc_ops = {
1321         .proc_open      = nonseekable_open,
1322         .proc_write     = cio_settle_write,
1323         .proc_lseek     = no_llseek,
1324 };
1325
1326 static int __init cio_settle_init(void)
1327 {
1328         struct proc_dir_entry *entry;
1329
1330         entry = proc_create("cio_settle", S_IWUSR, NULL, &cio_settle_proc_ops);
1331         if (!entry)
1332                 return -ENOMEM;
1333         return 0;
1334 }
1335 device_initcall(cio_settle_init);
1336 #endif /*CONFIG_PROC_FS*/
1337
1338 int sch_is_pseudo_sch(struct subchannel *sch)
1339 {
1340         if (!sch->dev.parent)
1341                 return 0;
1342         return sch == to_css(sch->dev.parent)->pseudo_subchannel;
1343 }
1344
1345 static int css_bus_match(struct device *dev, struct device_driver *drv)
1346 {
1347         struct subchannel *sch = to_subchannel(dev);
1348         struct css_driver *driver = to_cssdriver(drv);
1349         struct css_device_id *id;
1350
1351         /* When driver_override is set, only bind to the matching driver */
1352         if (sch->driver_override && strcmp(sch->driver_override, drv->name))
1353                 return 0;
1354
1355         for (id = driver->subchannel_type; id->match_flags; id++) {
1356                 if (sch->st == id->type)
1357                         return 1;
1358         }
1359
1360         return 0;
1361 }
1362
1363 static int css_probe(struct device *dev)
1364 {
1365         struct subchannel *sch;
1366         int ret;
1367
1368         sch = to_subchannel(dev);
1369         sch->driver = to_cssdriver(dev->driver);
1370         ret = sch->driver->probe ? sch->driver->probe(sch) : 0;
1371         if (ret)
1372                 sch->driver = NULL;
1373         return ret;
1374 }
1375
1376 static int css_remove(struct device *dev)
1377 {
1378         struct subchannel *sch;
1379         int ret;
1380
1381         sch = to_subchannel(dev);
1382         ret = sch->driver->remove ? sch->driver->remove(sch) : 0;
1383         sch->driver = NULL;
1384         return ret;
1385 }
1386
1387 static void css_shutdown(struct device *dev)
1388 {
1389         struct subchannel *sch;
1390
1391         sch = to_subchannel(dev);
1392         if (sch->driver && sch->driver->shutdown)
1393                 sch->driver->shutdown(sch);
1394 }
1395
1396 static int css_uevent(struct device *dev, struct kobj_uevent_env *env)
1397 {
1398         struct subchannel *sch = to_subchannel(dev);
1399         int ret;
1400
1401         ret = add_uevent_var(env, "ST=%01X", sch->st);
1402         if (ret)
1403                 return ret;
1404         ret = add_uevent_var(env, "MODALIAS=css:t%01X", sch->st);
1405         return ret;
1406 }
1407
1408 static struct bus_type css_bus_type = {
1409         .name     = "css",
1410         .match    = css_bus_match,
1411         .probe    = css_probe,
1412         .remove   = css_remove,
1413         .shutdown = css_shutdown,
1414         .uevent   = css_uevent,
1415 };
1416
1417 /**
1418  * css_driver_register - register a css driver
1419  * @cdrv: css driver to register
1420  *
1421  * This is mainly a wrapper around driver_register that sets name
1422  * and bus_type in the embedded struct device_driver correctly.
1423  */
1424 int css_driver_register(struct css_driver *cdrv)
1425 {
1426         cdrv->drv.bus = &css_bus_type;
1427         return driver_register(&cdrv->drv);
1428 }
1429 EXPORT_SYMBOL_GPL(css_driver_register);
1430
1431 /**
1432  * css_driver_unregister - unregister a css driver
1433  * @cdrv: css driver to unregister
1434  *
1435  * This is a wrapper around driver_unregister.
1436  */
1437 void css_driver_unregister(struct css_driver *cdrv)
1438 {
1439         driver_unregister(&cdrv->drv);
1440 }
1441 EXPORT_SYMBOL_GPL(css_driver_unregister);