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_lock;
 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_lock;
 244
 245         return sch;
 246
 247 err_lock:
 248         kfree(sch->lock);
 249 err:
 250         kfree(sch);
 251         return ERR_PTR(ret);
 252 }
 253
 254 static int css_sch_device_register(struct subchannel *sch)
 255 {
 256         int ret;
 257
 258         mutex_lock(&sch->reg_mutex);
 259         dev_set_name(&sch->dev, "0.%x.%04x", sch->schid.ssid,
 260                      sch->schid.sch_no);
 261         ret = device_add(&sch->dev);
 262         mutex_unlock(&sch->reg_mutex);
 263         return ret;
 264 }
 265
 266 /**
 267  * css_sch_device_unregister - unregister a subchannel
 268  * @sch: subchannel to be unregistered
 269  */
 270 void css_sch_device_unregister(struct subchannel *sch)
 271 {
 272         mutex_lock(&sch->reg_mutex);
 273         if (device_is_registered(&sch->dev))
 274                 device_unregister(&sch->dev);
 275         mutex_unlock(&sch->reg_mutex);
 276 }
 277 EXPORT_SYMBOL_GPL(css_sch_device_unregister);
 278
 279 static void ssd_from_pmcw(struct chsc_ssd_info *ssd, struct pmcw *pmcw)
 280 {
 281         int i;
 282         int mask;
 283
 284         memset(ssd, 0, sizeof(struct chsc_ssd_info));
 285         ssd->path_mask = pmcw->pim;
 286         for (i = 0; i < 8; i++) {
 287                 mask = 0x80 >> i;
 288                 if (pmcw->pim & mask) {
 289                         chp_id_init(&ssd->chpid[i]);
 290                         ssd->chpid[i].id = pmcw->chpid[i];
 291                 }
 292         }
 293 }
 294
 295 static void ssd_register_chpids(struct chsc_ssd_info *ssd)
 296 {
 297         int i;
 298         int mask;
 299
 300         for (i = 0; i < 8; i++) {
 301                 mask = 0x80 >> i;
 302                 if (ssd->path_mask & mask)
 303                         chp_new(ssd->chpid[i]);
 304         }
 305 }
 306
 307 void css_update_ssd_info(struct subchannel *sch)
 308 {
 309         int ret;
 310
 311         ret = chsc_get_ssd_info(sch->schid, &sch->ssd_info);
 312         if (ret)
 313                 ssd_from_pmcw(&sch->ssd_info, &sch->schib.pmcw);
 314
 315         ssd_register_chpids(&sch->ssd_info);
 316 }
 317
 318 static ssize_t type_show(struct device *dev, struct device_attribute *attr,
 319                          char *buf)
 320 {
 321         struct subchannel *sch = to_subchannel(dev);
 322
 323         return sprintf(buf, "%01x\n", sch->st);
 324 }
 325
 326 static DEVICE_ATTR_RO(type);
 327
 328 static ssize_t modalias_show(struct device *dev, struct device_attribute *attr,
 329                              char *buf)
 330 {
 331         struct subchannel *sch = to_subchannel(dev);
 332
 333         return sprintf(buf, "css:t%01X\n", sch->st);
 334 }
 335
 336 static DEVICE_ATTR_RO(modalias);
 337
 338 static ssize_t driver_override_store(struct device *dev,
 339                                      struct device_attribute *attr,
 340                                      const char *buf, size_t count)
 341 {
 342         struct subchannel *sch = to_subchannel(dev);
 343         int ret;
 344
 345         ret = driver_set_override(dev, &sch->driver_override, buf, count);
 346         if (ret)
 347                 return ret;
 348
 349         return count;
 350 }
 351
 352 static ssize_t driver_override_show(struct device *dev,
 353                                     struct device_attribute *attr, char *buf)
 354 {
 355         struct subchannel *sch = to_subchannel(dev);
 356         ssize_t len;
 357
 358         device_lock(dev);
 359         len = snprintf(buf, PAGE_SIZE, "%s\n", sch->driver_override);
 360         device_unlock(dev);
 361         return len;
 362 }
 363 static DEVICE_ATTR_RW(driver_override);
 364
 365 static struct attribute *subch_attrs[] = {
 366         &dev_attr_type.attr,
 367         &dev_attr_modalias.attr,
 368         &dev_attr_driver_override.attr,
 369         NULL,
 370 };
 371
 372 static struct attribute_group subch_attr_group = {
 373         .attrs = subch_attrs,
 374 };
 375
 376 static const struct attribute_group *default_subch_attr_groups[] = {
 377         &subch_attr_group,
 378         NULL,
 379 };
 380
 381 static ssize_t chpids_show(struct device *dev,
 382                            struct device_attribute *attr,
 383                            char *buf)
 384 {
 385         struct subchannel *sch = to_subchannel(dev);
 386         struct chsc_ssd_info *ssd = &sch->ssd_info;
 387         ssize_t ret = 0;
 388         int mask;
 389         int chp;
 390
 391         for (chp = 0; chp < 8; chp++) {
 392                 mask = 0x80 >> chp;
 393                 if (ssd->path_mask & mask)
 394                         ret += sprintf(buf + ret, "%02x ", ssd->chpid[chp].id);
 395                 else
 396                         ret += sprintf(buf + ret, "00 ");
 397         }
 398         ret += sprintf(buf + ret, "\n");
 399         return ret;
 400 }
 401 static DEVICE_ATTR_RO(chpids);
 402
 403 static ssize_t pimpampom_show(struct device *dev,
 404                               struct device_attribute *attr,
 405                               char *buf)
 406 {
 407         struct subchannel *sch = to_subchannel(dev);
 408         struct pmcw *pmcw = &sch->schib.pmcw;
 409
 410         return sprintf(buf, "%02x %02x %02x\n",
 411                        pmcw->pim, pmcw->pam, pmcw->pom);
 412 }
 413 static DEVICE_ATTR_RO(pimpampom);
 414
 415 static ssize_t dev_busid_show(struct device *dev,
 416                               struct device_attribute *attr,
 417                               char *buf)
 418 {
 419         struct subchannel *sch = to_subchannel(dev);
 420         struct pmcw *pmcw = &sch->schib.pmcw;
 421
 422         if ((pmcw->st == SUBCHANNEL_TYPE_IO && pmcw->dnv) ||
 423             (pmcw->st == SUBCHANNEL_TYPE_MSG && pmcw->w))
 424                 return sysfs_emit(buf, "0.%x.%04x\n", sch->schid.ssid,
 425                                   pmcw->dev);
 426         else
 427                 return sysfs_emit(buf, "none\n");
 428 }
 429 static DEVICE_ATTR_RO(dev_busid);
 430
 431 static struct attribute *io_subchannel_type_attrs[] = {
 432         &dev_attr_chpids.attr,
 433         &dev_attr_pimpampom.attr,
 434         &dev_attr_dev_busid.attr,
 435         NULL,
 436 };
 437 ATTRIBUTE_GROUPS(io_subchannel_type);
 438
 439 static const struct device_type io_subchannel_type = {
 440         .groups = io_subchannel_type_groups,
 441 };
 442
 443 int css_register_subchannel(struct subchannel *sch)
 444 {
 445         int ret;
 446
 447         /* Initialize the subchannel structure */
 448         sch->dev.parent = &channel_subsystems[0]->device;
 449         sch->dev.bus = &css_bus_type;
 450         sch->dev.groups = default_subch_attr_groups;
 451
 452         if (sch->st == SUBCHANNEL_TYPE_IO)
 453                 sch->dev.type = &io_subchannel_type;
 454
 455         css_update_ssd_info(sch);
 456         /* make it known to the system */
 457         ret = css_sch_device_register(sch);
 458         if (ret) {
 459                 CIO_MSG_EVENT(0, "Could not register sch 0.%x.%04x: %d\n",
 460                               sch->schid.ssid, sch->schid.sch_no, ret);
 461                 return ret;
 462         }
 463         return ret;
 464 }
 465
 466 static int css_probe_device(struct subchannel_id schid, struct schib *schib)
 467 {
 468         struct subchannel *sch;
 469         int ret;
 470
 471         sch = css_alloc_subchannel(schid, schib);
 472         if (IS_ERR(sch))
 473                 return PTR_ERR(sch);
 474
 475         ret = css_register_subchannel(sch);
 476         if (ret)
 477                 put_device(&sch->dev);
 478
 479         return ret;
 480 }
 481
 482 static int
 483 check_subchannel(struct device *dev, const void *data)
 484 {
 485         struct subchannel *sch;
 486         struct subchannel_id *schid = (void *)data;
 487
 488         sch = to_subchannel(dev);
 489         return schid_equal(&sch->schid, schid);
 490 }
 491
 492 struct subchannel *
 493 get_subchannel_by_schid(struct subchannel_id schid)
 494 {
 495         struct device *dev;
 496
 497         dev = bus_find_device(&css_bus_type, NULL,
 498                               &schid, check_subchannel);
 499
 500         return dev ? to_subchannel(dev) : NULL;
 501 }
 502
 503 /**
 504  * css_sch_is_valid() - check if a subchannel is valid
 505  * @schib: subchannel information block for the subchannel
 506  */
 507 int css_sch_is_valid(struct schib *schib)
 508 {
 509         if ((schib->pmcw.st == SUBCHANNEL_TYPE_IO) && !schib->pmcw.dnv)
 510                 return 0;
 511         if ((schib->pmcw.st == SUBCHANNEL_TYPE_MSG) && !schib->pmcw.w)
 512                 return 0;
 513         return 1;
 514 }
 515 EXPORT_SYMBOL_GPL(css_sch_is_valid);
 516
 517 static int css_evaluate_new_subchannel(struct subchannel_id schid, int slow)
 518 {
 519         struct schib schib;
 520         int ccode;
 521
 522         if (!slow) {
 523                 /* Will be done on the slow path. */
 524                 return -EAGAIN;
 525         }
 526         /*
 527          * The first subchannel that is not-operational (ccode==3)
 528          * indicates that there aren't any more devices available.
 529          * If stsch gets an exception, it means the current subchannel set
 530          * is not valid.
 531          */
 532         ccode = stsch(schid, &schib);
 533         if (ccode)
 534                 return (ccode == 3) ? -ENXIO : ccode;
 535
 536         return css_probe_device(schid, &schib);
 537 }
 538
 539 static int css_evaluate_known_subchannel(struct subchannel *sch, int slow)
 540 {
 541         int ret = 0;
 542
 543         if (sch->driver) {
 544                 if (sch->driver->sch_event)
 545                         ret = sch->driver->sch_event(sch, slow);
 546                 else
 547                         dev_dbg(&sch->dev,
 548                                 "Got subchannel machine check but "
 549                                 "no sch_event handler provided.\n");
 550         }
 551         if (ret != 0 && ret != -EAGAIN) {
 552                 CIO_MSG_EVENT(2, "eval: sch 0.%x.%04x, rc=%d\n",
 553                               sch->schid.ssid, sch->schid.sch_no, ret);
 554         }
 555         return ret;
 556 }
 557
 558 static void css_evaluate_subchannel(struct subchannel_id schid, int slow)
 559 {
 560         struct subchannel *sch;
 561         int ret;
 562
 563         sch = get_subchannel_by_schid(schid);
 564         if (sch) {
 565                 ret = css_evaluate_known_subchannel(sch, slow);
 566                 put_device(&sch->dev);
 567         } else
 568                 ret = css_evaluate_new_subchannel(schid, slow);
 569         if (ret == -EAGAIN)
 570                 css_schedule_eval(schid);
 571 }
 572
 573 /**
 574  * css_sched_sch_todo - schedule a subchannel operation
 575  * @sch: subchannel
 576  * @todo: todo
 577  *
 578  * Schedule the operation identified by @todo to be performed on the slow path
 579  * workqueue. Do nothing if another operation with higher priority is already
 580  * scheduled. Needs to be called with subchannel lock held.
 581  */
 582 void css_sched_sch_todo(struct subchannel *sch, enum sch_todo todo)
 583 {
 584         CIO_MSG_EVENT(4, "sch_todo: sched sch=0.%x.%04x todo=%d\n",
 585                       sch->schid.ssid, sch->schid.sch_no, todo);
 586         if (sch->todo >= todo)
 587                 return;
 588         /* Get workqueue ref. */
 589         if (!get_device(&sch->dev))
 590                 return;
 591         sch->todo = todo;
 592         if (!queue_work(cio_work_q, &sch->todo_work)) {
 593                 /* Already queued, release workqueue ref. */
 594                 put_device(&sch->dev);
 595         }
 596 }
 597 EXPORT_SYMBOL_GPL(css_sched_sch_todo);
 598
 599 static void css_sch_todo(struct work_struct *work)
 600 {
 601         struct subchannel *sch;
 602         enum sch_todo todo;
 603         int ret;
 604
 605         sch = container_of(work, struct subchannel, todo_work);
 606         /* Find out todo. */
 607         spin_lock_irq(sch->lock);
 608         todo = sch->todo;
 609         CIO_MSG_EVENT(4, "sch_todo: sch=0.%x.%04x, todo=%d\n", sch->schid.ssid,
 610                       sch->schid.sch_no, todo);
 611         sch->todo = SCH_TODO_NOTHING;
 612         spin_unlock_irq(sch->lock);
 613         /* Perform todo. */
 614         switch (todo) {
 615         case SCH_TODO_NOTHING:
 616                 break;
 617         case SCH_TODO_EVAL:
 618                 ret = css_evaluate_known_subchannel(sch, 1);
 619                 if (ret == -EAGAIN) {
 620                         spin_lock_irq(sch->lock);
 621                         css_sched_sch_todo(sch, todo);
 622                         spin_unlock_irq(sch->lock);
 623                 }
 624                 break;
 625         case SCH_TODO_UNREG:
 626                 css_sch_device_unregister(sch);
 627                 break;
 628         }
 629         /* Release workqueue ref. */
 630         put_device(&sch->dev);
 631 }
 632
 633 static struct idset *slow_subchannel_set;
 634 static DEFINE_SPINLOCK(slow_subchannel_lock);
 635 static DECLARE_WAIT_QUEUE_HEAD(css_eval_wq);
 636 static atomic_t css_eval_scheduled;
 637
 638 static int __init slow_subchannel_init(void)
 639 {
 640         atomic_set(&css_eval_scheduled, 0);
 641         slow_subchannel_set = idset_sch_new();
 642         if (!slow_subchannel_set) {
 643                 CIO_MSG_EVENT(0, "could not allocate slow subchannel set\n");
 644                 return -ENOMEM;
 645         }
 646         return 0;
 647 }
 648
 649 static int slow_eval_known_fn(struct subchannel *sch, void *data)
 650 {
 651         int eval;
 652         int rc;
 653
 654         spin_lock_irq(&slow_subchannel_lock);
 655         eval = idset_sch_contains(slow_subchannel_set, sch->schid);
 656         idset_sch_del(slow_subchannel_set, sch->schid);
 657         spin_unlock_irq(&slow_subchannel_lock);
 658         if (eval) {
 659                 rc = css_evaluate_known_subchannel(sch, 1);
 660                 if (rc == -EAGAIN)
 661                         css_schedule_eval(sch->schid);
 662                 /*
 663                  * The loop might take long time for platforms with lots of
 664                  * known devices. Allow scheduling here.
 665                  */
 666                 cond_resched();
 667         }
 668         return 0;
 669 }
 670
 671 static int slow_eval_unknown_fn(struct subchannel_id schid, void *data)
 672 {
 673         int eval;
 674         int rc = 0;
 675
 676         spin_lock_irq(&slow_subchannel_lock);
 677         eval = idset_sch_contains(slow_subchannel_set, schid);
 678         idset_sch_del(slow_subchannel_set, schid);
 679         spin_unlock_irq(&slow_subchannel_lock);
 680         if (eval) {
 681                 rc = css_evaluate_new_subchannel(schid, 1);
 682                 switch (rc) {
 683                 case -EAGAIN:
 684                         css_schedule_eval(schid);
 685                         rc = 0;
 686                         break;
 687                 case -ENXIO:
 688                 case -ENOMEM:
 689                 case -EIO:
 690                         /* These should abort looping */
 691                         spin_lock_irq(&slow_subchannel_lock);
 692                         idset_sch_del_subseq(slow_subchannel_set, schid);
 693                         spin_unlock_irq(&slow_subchannel_lock);
 694                         break;
 695                 default:
 696                         rc = 0;
 697                 }
 698                 /* Allow scheduling here since the containing loop might
 699                  * take a while.  */
 700                 cond_resched();
 701         }
 702         return rc;
 703 }
 704
 705 static void css_slow_path_func(struct work_struct *unused)
 706 {
 707         unsigned long flags;
 708
 709         CIO_TRACE_EVENT(4, "slowpath");
 710         for_each_subchannel_staged(slow_eval_known_fn, slow_eval_unknown_fn,
 711                                    NULL);
 712         spin_lock_irqsave(&slow_subchannel_lock, flags);
 713         if (idset_is_empty(slow_subchannel_set)) {
 714                 atomic_set(&css_eval_scheduled, 0);
 715                 wake_up(&css_eval_wq);
 716         }
 717         spin_unlock_irqrestore(&slow_subchannel_lock, flags);
 718 }
 719
 720 static DECLARE_DELAYED_WORK(slow_path_work, css_slow_path_func);
 721 struct workqueue_struct *cio_work_q;
 722
 723 void css_schedule_eval(struct subchannel_id schid)
 724 {
 725         unsigned long flags;
 726
 727         spin_lock_irqsave(&slow_subchannel_lock, flags);
 728         idset_sch_add(slow_subchannel_set, schid);
 729         atomic_set(&css_eval_scheduled, 1);
 730         queue_delayed_work(cio_work_q, &slow_path_work, 0);
 731         spin_unlock_irqrestore(&slow_subchannel_lock, flags);
 732 }
 733
 734 void css_schedule_eval_all(void)
 735 {
 736         unsigned long flags;
 737
 738         spin_lock_irqsave(&slow_subchannel_lock, flags);
 739         idset_fill(slow_subchannel_set);
 740         atomic_set(&css_eval_scheduled, 1);
 741         queue_delayed_work(cio_work_q, &slow_path_work, 0);
 742         spin_unlock_irqrestore(&slow_subchannel_lock, flags);
 743 }
 744
 745 static int __unset_validpath(struct device *dev, void *data)
 746 {
 747         struct idset *set = data;
 748         struct subchannel *sch = to_subchannel(dev);
 749         struct pmcw *pmcw = &sch->schib.pmcw;
 750
 751         /* Here we want to make sure that we are considering only those subchannels
 752          * which do not have an operational device attached to it. This can be found
 753          * with the help of PAM and POM values of pmcw. OPM provides the information
 754          * about any path which is currently vary-off, so that we should not consider.
 755          */
 756         if (sch->st == SUBCHANNEL_TYPE_IO &&
 757             (sch->opm & pmcw->pam & pmcw->pom))
 758                 idset_sch_del(set, sch->schid);
 759
 760         return 0;
 761 }
 762
 763 static int __unset_online(struct device *dev, void *data)
 764 {
 765         struct idset *set = data;
 766         struct subchannel *sch = to_subchannel(dev);
 767
 768         if (sch->st == SUBCHANNEL_TYPE_IO && sch->config.ena)
 769                 idset_sch_del(set, sch->schid);
 770
 771         return 0;
 772 }
 773
 774 void css_schedule_eval_cond(enum css_eval_cond cond, unsigned long delay)
 775 {
 776         unsigned long flags;
 777         struct idset *set;
 778
 779         /* Find unregistered subchannels. */
 780         set = idset_sch_new();
 781         if (!set) {
 782                 /* Fallback. */
 783                 css_schedule_eval_all();
 784                 return;
 785         }
 786         idset_fill(set);
 787         switch (cond) {
 788         case CSS_EVAL_NO_PATH:
 789                 bus_for_each_dev(&css_bus_type, NULL, set, __unset_validpath);
 790                 break;
 791         case CSS_EVAL_NOT_ONLINE:
 792                 bus_for_each_dev(&css_bus_type, NULL, set, __unset_online);
 793                 break;
 794         default:
 795                 break;
 796         }
 797
 798         /* Apply to slow_subchannel_set. */
 799         spin_lock_irqsave(&slow_subchannel_lock, flags);
 800         idset_add_set(slow_subchannel_set, set);
 801         atomic_set(&css_eval_scheduled, 1);
 802         queue_delayed_work(cio_work_q, &slow_path_work, delay);
 803         spin_unlock_irqrestore(&slow_subchannel_lock, flags);
 804         idset_free(set);
 805 }
 806
 807 void css_wait_for_slow_path(void)
 808 {
 809         flush_workqueue(cio_work_q);
 810 }
 811
 812 /* Schedule reprobing of all subchannels with no valid operational path. */
 813 void css_schedule_reprobe(void)
 814 {
 815         /* Schedule with a delay to allow merging of subsequent calls. */
 816         css_schedule_eval_cond(CSS_EVAL_NO_PATH, 1 * HZ);
 817 }
 818 EXPORT_SYMBOL_GPL(css_schedule_reprobe);
 819
 820 /*
 821  * Called from the machine check handler for subchannel report words.
 822  */
 823 static void css_process_crw(struct crw *crw0, struct crw *crw1, int overflow)
 824 {
 825         struct subchannel_id mchk_schid;
 826         struct subchannel *sch;
 827
 828         if (overflow) {
 829                 css_schedule_eval_all();
 830                 return;
 831         }
 832         CIO_CRW_EVENT(2, "CRW0 reports slct=%d, oflw=%d, "
 833                       "chn=%d, rsc=%X, anc=%d, erc=%X, rsid=%X\n",
 834                       crw0->slct, crw0->oflw, crw0->chn, crw0->rsc, crw0->anc,
 835                       crw0->erc, crw0->rsid);
 836         if (crw1)
 837                 CIO_CRW_EVENT(2, "CRW1 reports slct=%d, oflw=%d, "
 838                               "chn=%d, rsc=%X, anc=%d, erc=%X, rsid=%X\n",
 839                               crw1->slct, crw1->oflw, crw1->chn, crw1->rsc,
 840                               crw1->anc, crw1->erc, crw1->rsid);
 841         init_subchannel_id(&mchk_schid);
 842         mchk_schid.sch_no = crw0->rsid;
 843         if (crw1)
 844                 mchk_schid.ssid = (crw1->rsid >> 4) & 3;
 845
 846         if (crw0->erc == CRW_ERC_PMOD) {
 847                 sch = get_subchannel_by_schid(mchk_schid);
 848                 if (sch) {
 849                         css_update_ssd_info(sch);
 850                         put_device(&sch->dev);
 851                 }
 852         }
 853         /*
 854          * Since we are always presented with IPI in the CRW, we have to
 855          * use stsch() to find out if the subchannel in question has come
 856          * or gone.
 857          */
 858         css_evaluate_subchannel(mchk_schid, 0);
 859 }
 860
 861 static void __init
 862 css_generate_pgid(struct channel_subsystem *css, u32 tod_high)
 863 {
 864         struct cpuid cpu_id;
 865
 866         if (css_general_characteristics.mcss) {
 867                 css->global_pgid.pgid_high.ext_cssid.version = 0x80;
 868                 css->global_pgid.pgid_high.ext_cssid.cssid =
 869                         css->id_valid ? css->cssid : 0;
 870         } else {
 871                 css->global_pgid.pgid_high.cpu_addr = stap();
 872         }
 873         get_cpu_id(&cpu_id);
 874         css->global_pgid.cpu_id = cpu_id.ident;
 875         css->global_pgid.cpu_model = cpu_id.machine;
 876         css->global_pgid.tod_high = tod_high;
 877 }
 878
 879 static void channel_subsystem_release(struct device *dev)
 880 {
 881         struct channel_subsystem *css = to_css(dev);
 882
 883         mutex_destroy(&css->mutex);
 884         kfree(css);
 885 }
 886
 887 static ssize_t real_cssid_show(struct device *dev, struct device_attribute *a,
 888                                char *buf)
 889 {
 890         struct channel_subsystem *css = to_css(dev);
 891
 892         if (!css->id_valid)
 893                 return -EINVAL;
 894
 895         return sprintf(buf, "%x\n", css->cssid);
 896 }
 897 static DEVICE_ATTR_RO(real_cssid);
 898
 899 static ssize_t rescan_store(struct device *dev, struct device_attribute *a,
 900                             const char *buf, size_t count)
 901 {
 902         CIO_TRACE_EVENT(4, "usr-rescan");
 903
 904         css_schedule_eval_all();
 905         css_complete_work();
 906
 907         return count;
 908 }
 909 static DEVICE_ATTR_WO(rescan);
 910
 911 static ssize_t cm_enable_show(struct device *dev, struct device_attribute *a,
 912                               char *buf)
 913 {
 914         struct channel_subsystem *css = to_css(dev);
 915         int ret;
 916
 917         mutex_lock(&css->mutex);
 918         ret = sprintf(buf, "%x\n", css->cm_enabled);
 919         mutex_unlock(&css->mutex);
 920         return ret;
 921 }
 922
 923 static ssize_t cm_enable_store(struct device *dev, struct device_attribute *a,
 924                                const char *buf, size_t count)
 925 {
 926         struct channel_subsystem *css = to_css(dev);
 927         unsigned long val;
 928         int ret;
 929
 930         ret = kstrtoul(buf, 16, &val);
 931         if (ret)
 932                 return ret;
 933         mutex_lock(&css->mutex);
 934         switch (val) {
 935         case 0:
 936                 ret = css->cm_enabled ? chsc_secm(css, 0) : 0;
 937                 break;
 938         case 1:
 939                 ret = css->cm_enabled ? 0 : chsc_secm(css, 1);
 940                 break;
 941         default:
 942                 ret = -EINVAL;
 943         }
 944         mutex_unlock(&css->mutex);
 945         return ret < 0 ? ret : count;
 946 }
 947 static DEVICE_ATTR_RW(cm_enable);
 948
 949 static umode_t cm_enable_mode(struct kobject *kobj, struct attribute *attr,
 950                               int index)
 951 {
 952         return css_chsc_characteristics.secm ? attr->mode : 0;
 953 }
 954
 955 static struct attribute *cssdev_attrs[] = {
 956         &dev_attr_real_cssid.attr,
 957         &dev_attr_rescan.attr,
 958         NULL,
 959 };
 960
 961 static struct attribute_group cssdev_attr_group = {
 962         .attrs = cssdev_attrs,
 963 };
 964
 965 static struct attribute *cssdev_cm_attrs[] = {
 966         &dev_attr_cm_enable.attr,
 967         NULL,
 968 };
 969
 970 static struct attribute_group cssdev_cm_attr_group = {
 971         .attrs = cssdev_cm_attrs,
 972         .is_visible = cm_enable_mode,
 973 };
 974
 975 static const struct attribute_group *cssdev_attr_groups[] = {
 976         &cssdev_attr_group,
 977         &cssdev_cm_attr_group,
 978         NULL,
 979 };
 980
 981 static int __init setup_css(int nr)
 982 {
 983         struct channel_subsystem *css;
 984         int ret;
 985
 986         css = kzalloc(sizeof(*css), GFP_KERNEL);
 987         if (!css)
 988                 return -ENOMEM;
 989
 990         channel_subsystems[nr] = css;
 991         dev_set_name(&css->device, "css%x", nr);
 992         css->device.groups = cssdev_attr_groups;
 993         css->device.release = channel_subsystem_release;
 994         /*
 995          * We currently allocate notifier bits with this (using
 996          * css->device as the device argument with the DMA API)
 997          * and are fine with 64 bit addresses.
 998          */
 999         ret = dma_coerce_mask_and_coherent(&css->device, DMA_BIT_MASK(64));
1000         if (ret) {
1001                 kfree(css);
1002                 goto out_err;
1003         }
1004
1005         mutex_init(&css->mutex);
1006         ret = chsc_get_cssid_iid(nr, &css->cssid, &css->iid);
1007         if (!ret) {
1008                 css->id_valid = true;
1009                 pr_info("Partition identifier %01x.%01x\n", css->cssid,
1010                         css->iid);
1011         }
1012         css_generate_pgid(css, (u32) (get_tod_clock() >> 32));
1013
1014         ret = device_register(&css->device);
1015         if (ret) {
1016                 put_device(&css->device);
1017                 goto out_err;
1018         }
1019
1020         css->pseudo_subchannel = kzalloc(sizeof(*css->pseudo_subchannel),
1021                                          GFP_KERNEL);
1022         if (!css->pseudo_subchannel) {
1023                 device_unregister(&css->device);
1024                 ret = -ENOMEM;
1025                 goto out_err;
1026         }
1027
1028         css->pseudo_subchannel->dev.parent = &css->device;
1029         css->pseudo_subchannel->dev.release = css_subchannel_release;
1030         mutex_init(&css->pseudo_subchannel->reg_mutex);
1031         ret = css_sch_create_locks(css->pseudo_subchannel);
1032         if (ret) {
1033                 kfree(css->pseudo_subchannel);
1034                 device_unregister(&css->device);
1035                 goto out_err;
1036         }
1037
1038         dev_set_name(&css->pseudo_subchannel->dev, "defunct");
1039         ret = device_register(&css->pseudo_subchannel->dev);
1040         if (ret) {
1041                 put_device(&css->pseudo_subchannel->dev);
1042                 device_unregister(&css->device);
1043                 goto out_err;
1044         }
1045
1046         return ret;
1047 out_err:
1048         channel_subsystems[nr] = NULL;
1049         return ret;
1050 }
1051
1052 static int css_reboot_event(struct notifier_block *this,
1053                             unsigned long event,
1054                             void *ptr)
1055 {
1056         struct channel_subsystem *css;
1057         int ret;
1058
1059         ret = NOTIFY_DONE;
1060         for_each_css(css) {
1061                 mutex_lock(&css->mutex);
1062                 if (css->cm_enabled)
1063                         if (chsc_secm(css, 0))
1064                                 ret = NOTIFY_BAD;
1065                 mutex_unlock(&css->mutex);
1066         }
1067
1068         return ret;
1069 }
1070
1071 static struct notifier_block css_reboot_notifier = {
1072         .notifier_call = css_reboot_event,
1073 };
1074
1075 #define  CIO_DMA_GFP (GFP_KERNEL | __GFP_ZERO)
1076 static struct gen_pool *cio_dma_pool;
1077
1078 /* Currently cio supports only a single css */
1079 struct device *cio_get_dma_css_dev(void)
1080 {
1081         return &channel_subsystems[0]->device;
1082 }
1083
1084 struct gen_pool *cio_gp_dma_create(struct device *dma_dev, int nr_pages)
1085 {
1086         struct gen_pool *gp_dma;
1087         void *cpu_addr;
1088         dma_addr_t dma_addr;
1089         int i;
1090
1091         gp_dma = gen_pool_create(3, -1);
1092         if (!gp_dma)
1093                 return NULL;
1094         for (i = 0; i < nr_pages; ++i) {
1095                 cpu_addr = dma_alloc_coherent(dma_dev, PAGE_SIZE, &dma_addr,
1096                                               CIO_DMA_GFP);
1097                 if (!cpu_addr)
1098                         return gp_dma;
1099                 gen_pool_add_virt(gp_dma, (unsigned long) cpu_addr,
1100                                   dma_addr, PAGE_SIZE, -1);
1101         }
1102         return gp_dma;
1103 }
1104
1105 static void __gp_dma_free_dma(struct gen_pool *pool,
1106                               struct gen_pool_chunk *chunk, void *data)
1107 {
1108         size_t chunk_size = chunk->end_addr - chunk->start_addr + 1;
1109
1110         dma_free_coherent((struct device *) data, chunk_size,
1111                          (void *) chunk->start_addr,
1112                          (dma_addr_t) chunk->phys_addr);
1113 }
1114
1115 void cio_gp_dma_destroy(struct gen_pool *gp_dma, struct device *dma_dev)
1116 {
1117         if (!gp_dma)
1118                 return;
1119         /* this is quite ugly but no better idea */
1120         gen_pool_for_each_chunk(gp_dma, __gp_dma_free_dma, dma_dev);
1121         gen_pool_destroy(gp_dma);
1122 }
1123
1124 static int cio_dma_pool_init(void)
1125 {
1126         /* No need to free up the resources: compiled in */
1127         cio_dma_pool = cio_gp_dma_create(cio_get_dma_css_dev(), 1);
1128         if (!cio_dma_pool)
1129                 return -ENOMEM;
1130         return 0;
1131 }
1132
1133 void *cio_gp_dma_zalloc(struct gen_pool *gp_dma, struct device *dma_dev,
1134                         size_t size)
1135 {
1136         dma_addr_t dma_addr;
1137         unsigned long addr;
1138         size_t chunk_size;
1139
1140         if (!gp_dma)
1141                 return NULL;
1142         addr = gen_pool_alloc(gp_dma, size);
1143         while (!addr) {
1144                 chunk_size = round_up(size, PAGE_SIZE);
1145                 addr = (unsigned long) dma_alloc_coherent(dma_dev,
1146                                          chunk_size, &dma_addr, CIO_DMA_GFP);
1147                 if (!addr)
1148                         return NULL;
1149                 gen_pool_add_virt(gp_dma, addr, dma_addr, chunk_size, -1);
1150                 addr = gen_pool_alloc(gp_dma, size);
1151         }
1152         return (void *) addr;
1153 }
1154
1155 void cio_gp_dma_free(struct gen_pool *gp_dma, void *cpu_addr, size_t size)
1156 {
1157         if (!cpu_addr)
1158                 return;
1159         memset(cpu_addr, 0, size);
1160         gen_pool_free(gp_dma, (unsigned long) cpu_addr, size);
1161 }
1162
1163 /*
1164  * Allocate dma memory from the css global pool. Intended for memory not
1165  * specific to any single device within the css. The allocated memory
1166  * is not guaranteed to be 31-bit addressable.
1167  *
1168  * Caution: Not suitable for early stuff like console.
1169  */
1170 void *cio_dma_zalloc(size_t size)
1171 {
1172         return cio_gp_dma_zalloc(cio_dma_pool, cio_get_dma_css_dev(), size);
1173 }
1174
1175 void cio_dma_free(void *cpu_addr, size_t size)
1176 {
1177         cio_gp_dma_free(cio_dma_pool, cpu_addr, size);
1178 }
1179
1180 /*
1181  * Now that the driver core is running, we can setup our channel subsystem.
1182  * The struct subchannel's are created during probing.
1183  */
1184 static int __init css_bus_init(void)
1185 {
1186         int ret, i;
1187
1188         ret = chsc_init();
1189         if (ret)
1190                 return ret;
1191
1192         chsc_determine_css_characteristics();
1193         /* Try to enable MSS. */
1194         ret = chsc_enable_facility(CHSC_SDA_OC_MSS);
1195         if (ret)
1196                 max_ssid = 0;
1197         else /* Success. */
1198                 max_ssid = __MAX_SSID;
1199
1200         ret = slow_subchannel_init();
1201         if (ret)
1202                 goto out;
1203
1204         ret = crw_register_handler(CRW_RSC_SCH, css_process_crw);
1205         if (ret)
1206                 goto out;
1207
1208         if ((ret = bus_register(&css_bus_type)))
1209                 goto out;
1210
1211         /* Setup css structure. */
1212         for (i = 0; i <= MAX_CSS_IDX; i++) {
1213                 ret = setup_css(i);
1214                 if (ret)
1215                         goto out_unregister;
1216         }
1217         ret = register_reboot_notifier(&css_reboot_notifier);
1218         if (ret)
1219                 goto out_unregister;
1220         ret = cio_dma_pool_init();
1221         if (ret)
1222                 goto out_unregister_rn;
1223         airq_init();
1224         css_init_done = 1;
1225
1226         /* Enable default isc for I/O subchannels. */
1227         isc_register(IO_SCH_ISC);
1228
1229         return 0;
1230 out_unregister_rn:
1231         unregister_reboot_notifier(&css_reboot_notifier);
1232 out_unregister:
1233         while (i-- > 0) {
1234                 struct channel_subsystem *css = channel_subsystems[i];
1235                 device_unregister(&css->pseudo_subchannel->dev);
1236                 device_unregister(&css->device);
1237         }
1238         bus_unregister(&css_bus_type);
1239 out:
1240         crw_unregister_handler(CRW_RSC_SCH);
1241         idset_free(slow_subchannel_set);
1242         chsc_init_cleanup();
1243         pr_alert("The CSS device driver initialization failed with "
1244                  "errno=%d\n", ret);
1245         return ret;
1246 }
1247
1248 static void __init css_bus_cleanup(void)
1249 {
1250         struct channel_subsystem *css;
1251
1252         for_each_css(css) {
1253                 device_unregister(&css->pseudo_subchannel->dev);
1254                 device_unregister(&css->device);
1255         }
1256         bus_unregister(&css_bus_type);
1257         crw_unregister_handler(CRW_RSC_SCH);
1258         idset_free(slow_subchannel_set);
1259         chsc_init_cleanup();
1260         isc_unregister(IO_SCH_ISC);
1261 }
1262
1263 static int __init channel_subsystem_init(void)
1264 {
1265         int ret;
1266
1267         ret = css_bus_init();
1268         if (ret)
1269                 return ret;
1270         cio_work_q = create_singlethread_workqueue("cio");
1271         if (!cio_work_q) {
1272                 ret = -ENOMEM;
1273                 goto out_bus;
1274         }
1275         ret = io_subchannel_init();
1276         if (ret)
1277                 goto out_wq;
1278
1279         /* Register subchannels which are already in use. */
1280         cio_register_early_subchannels();
1281         /* Start initial subchannel evaluation. */
1282         css_schedule_eval_all();
1283
1284         return ret;
1285 out_wq:
1286         destroy_workqueue(cio_work_q);
1287 out_bus:
1288         css_bus_cleanup();
1289         return ret;
1290 }
1291 subsys_initcall(channel_subsystem_init);
1292
1293 static int css_settle(struct device_driver *drv, void *unused)
1294 {
1295         struct css_driver *cssdrv = to_cssdriver(drv);
1296
1297         if (cssdrv->settle)
1298                 return cssdrv->settle();
1299         return 0;
1300 }
1301
1302 int css_complete_work(void)
1303 {
1304         int ret;
1305
1306         /* Wait for the evaluation of subchannels to finish. */
1307         ret = wait_event_interruptible(css_eval_wq,
1308                                        atomic_read(&css_eval_scheduled) == 0);
1309         if (ret)
1310                 return -EINTR;
1311         flush_workqueue(cio_work_q);
1312         /* Wait for the subchannel type specific initialization to finish */
1313         return bus_for_each_drv(&css_bus_type, NULL, NULL, css_settle);
1314 }
1315
1316
1317 /*
1318  * Wait for the initialization of devices to finish, to make sure we are
1319  * done with our setup if the search for the root device starts.
1320  */
1321 static int __init channel_subsystem_init_sync(void)
1322 {
1323         css_complete_work();
1324         return 0;
1325 }
1326 subsys_initcall_sync(channel_subsystem_init_sync);
1327
1328 #ifdef CONFIG_PROC_FS
1329 static ssize_t cio_settle_write(struct file *file, const char __user *buf,
1330                                 size_t count, loff_t *ppos)
1331 {
1332         int ret;
1333
1334         /* Handle pending CRW's. */
1335         crw_wait_for_channel_report();
1336         ret = css_complete_work();
1337
1338         return ret ? ret : count;
1339 }
1340
1341 static const struct proc_ops cio_settle_proc_ops = {
1342         .proc_open      = nonseekable_open,
1343         .proc_write     = cio_settle_write,
1344         .proc_lseek     = no_llseek,
1345 };
1346
1347 static int __init cio_settle_init(void)
1348 {
1349         struct proc_dir_entry *entry;
1350
1351         entry = proc_create("cio_settle", S_IWUSR, NULL, &cio_settle_proc_ops);
1352         if (!entry)
1353                 return -ENOMEM;
1354         return 0;
1355 }
1356 device_initcall(cio_settle_init);
1357 #endif /*CONFIG_PROC_FS*/
1358
1359 int sch_is_pseudo_sch(struct subchannel *sch)
1360 {
1361         if (!sch->dev.parent)
1362                 return 0;
1363         return sch == to_css(sch->dev.parent)->pseudo_subchannel;
1364 }
1365
1366 static int css_bus_match(struct device *dev, struct device_driver *drv)
1367 {
1368         struct subchannel *sch = to_subchannel(dev);
1369         struct css_driver *driver = to_cssdriver(drv);
1370         struct css_device_id *id;
1371
1372         /* When driver_override is set, only bind to the matching driver */
1373         if (sch->driver_override && strcmp(sch->driver_override, drv->name))
1374                 return 0;
1375
1376         for (id = driver->subchannel_type; id->match_flags; id++) {
1377                 if (sch->st == id->type)
1378                         return 1;
1379         }
1380
1381         return 0;
1382 }
1383
1384 static int css_probe(struct device *dev)
1385 {
1386         struct subchannel *sch;
1387         int ret;
1388
1389         sch = to_subchannel(dev);
1390         sch->driver = to_cssdriver(dev->driver);
1391         ret = sch->driver->probe ? sch->driver->probe(sch) : 0;
1392         if (ret)
1393                 sch->driver = NULL;
1394         return ret;
1395 }
1396
1397 static void css_remove(struct device *dev)
1398 {
1399         struct subchannel *sch;
1400
1401         sch = to_subchannel(dev);
1402         if (sch->driver->remove)
1403                 sch->driver->remove(sch);
1404         sch->driver = NULL;
1405 }
1406
1407 static void css_shutdown(struct device *dev)
1408 {
1409         struct subchannel *sch;
1410
1411         sch = to_subchannel(dev);
1412         if (sch->driver && sch->driver->shutdown)
1413                 sch->driver->shutdown(sch);
1414 }
1415
1416 static int css_uevent(const struct device *dev, struct kobj_uevent_env *env)
1417 {
1418         const struct subchannel *sch = to_subchannel(dev);
1419         int ret;
1420
1421         ret = add_uevent_var(env, "ST=%01X", sch->st);
1422         if (ret)
1423                 return ret;
1424         ret = add_uevent_var(env, "MODALIAS=css:t%01X", sch->st);
1425         return ret;
1426 }
1427
1428 static struct bus_type css_bus_type = {
1429         .name     = "css",
1430         .match    = css_bus_match,
1431         .probe    = css_probe,
1432         .remove   = css_remove,
1433         .shutdown = css_shutdown,
1434         .uevent   = css_uevent,
1435 };
1436
1437 /**
1438  * css_driver_register - register a css driver
1439  * @cdrv: css driver to register
1440  *
1441  * This is mainly a wrapper around driver_register that sets name
1442  * and bus_type in the embedded struct device_driver correctly.
1443  */
1444 int css_driver_register(struct css_driver *cdrv)
1445 {
1446         cdrv->drv.bus = &css_bus_type;
1447         return driver_register(&cdrv->drv);
1448 }
1449 EXPORT_SYMBOL_GPL(css_driver_register);
1450
1451 /**
1452  * css_driver_unregister - unregister a css driver
1453  * @cdrv: css driver to unregister
1454  *
1455  * This is a wrapper around driver_unregister.
1456  */
1457 void css_driver_unregister(struct css_driver *cdrv)
1458 {
1459         driver_unregister(&cdrv->drv);
1460 }
1461 EXPORT_SYMBOL_GPL(css_driver_unregister);