drivers/s390/cio/css.c

   1 // SPDX-License-Identifier: GPL-2.0
   2 /*
   3  * driver for channel subsystem
   4  *
   5  * Copyright IBM Corp. 2002, 2010
   6  *
   7  * Author(s): Arnd Bergmann (arndb@de.ibm.com)
   8  *            Cornelia Huck (cornelia.huck@de.ibm.com)
   9  */
  10
  11 #define KMSG_COMPONENT "cio"
  12 #define pr_fmt(fmt) KMSG_COMPONENT ": " fmt
  13
  14 #include <linux/export.h>
  15 #include <linux/init.h>
  16 #include <linux/device.h>
  17 #include <linux/slab.h>
  18 #include <linux/errno.h>
  19 #include <linux/list.h>
  20 #include <linux/reboot.h>
  21 #include <linux/suspend.h>
  22 #include <linux/proc_fs.h>
  23 #include <asm/isc.h>
  24 #include <asm/crw.h>
  25
  26 #include "css.h"
  27 #include "cio.h"
  28 #include "cio_debug.h"
  29 #include "ioasm.h"
  30 #include "chsc.h"
  31 #include "device.h"
  32 #include "idset.h"
  33 #include "chp.h"
  34
  35 int css_init_done = 0;
  36 int max_ssid;
  37
  38 #define MAX_CSS_IDX 0
  39 struct channel_subsystem *channel_subsystems[MAX_CSS_IDX + 1];
  40 static struct bus_type css_bus_type;
  41
  42 int
  43 for_each_subchannel(int(*fn)(struct subchannel_id, void *), void *data)
  44 {
  45         struct subchannel_id schid;
  46         int ret;
  47
  48         init_subchannel_id(&schid);
  49         do {
  50                 do {
  51                         ret = fn(schid, data);
  52                         if (ret)
  53                                 break;
  54                 } while (schid.sch_no++ < __MAX_SUBCHANNEL);
  55                 schid.sch_no = 0;
  56         } while (schid.ssid++ < max_ssid);
  57         return ret;
  58 }
  59
  60 struct cb_data {
  61         void *data;
  62         struct idset *set;
  63         int (*fn_known_sch)(struct subchannel *, void *);
  64         int (*fn_unknown_sch)(struct subchannel_id, void *);
  65 };
  66
  67 static int call_fn_known_sch(struct device *dev, void *data)
  68 {
  69         struct subchannel *sch = to_subchannel(dev);
  70         struct cb_data *cb = data;
  71         int rc = 0;
  72
  73         if (cb->set)
  74                 idset_sch_del(cb->set, sch->schid);
  75         if (cb->fn_known_sch)
  76                 rc = cb->fn_known_sch(sch, cb->data);
  77         return rc;
  78 }
  79
  80 static int call_fn_unknown_sch(struct subchannel_id schid, void *data)
  81 {
  82         struct cb_data *cb = data;
  83         int rc = 0;
  84
  85         if (idset_sch_contains(cb->set, schid))
  86                 rc = cb->fn_unknown_sch(schid, cb->data);
  87         return rc;
  88 }
  89
  90 static int call_fn_all_sch(struct subchannel_id schid, void *data)
  91 {
  92         struct cb_data *cb = data;
  93         struct subchannel *sch;
  94         int rc = 0;
  95
  96         sch = get_subchannel_by_schid(schid);
  97         if (sch) {
  98                 if (cb->fn_known_sch)
  99                         rc = cb->fn_known_sch(sch, cb->data);
 100                 put_device(&sch->dev);
 101         } else {
 102                 if (cb->fn_unknown_sch)
 103                         rc = cb->fn_unknown_sch(schid, cb->data);
 104         }
 105
 106         return rc;
 107 }
 108
 109 int for_each_subchannel_staged(int (*fn_known)(struct subchannel *, void *),
 110                                int (*fn_unknown)(struct subchannel_id,
 111                                void *), void *data)
 112 {
 113         struct cb_data cb;
 114         int rc;
 115
 116         cb.data = data;
 117         cb.fn_known_sch = fn_known;
 118         cb.fn_unknown_sch = fn_unknown;
 119
 120         if (fn_known && !fn_unknown) {
 121                 /* Skip idset allocation in case of known-only loop. */
 122                 cb.set = NULL;
 123                 return bus_for_each_dev(&css_bus_type, NULL, &cb,
 124                                         call_fn_known_sch);
 125         }
 126
 127         cb.set = idset_sch_new();
 128         if (!cb.set)
 129                 /* fall back to brute force scanning in case of oom */
 130                 return for_each_subchannel(call_fn_all_sch, &cb);
 131
 132         idset_fill(cb.set);
 133
 134         /* Process registered subchannels. */
 135         rc = bus_for_each_dev(&css_bus_type, NULL, &cb, call_fn_known_sch);
 136         if (rc)
 137                 goto out;
 138         /* Process unregistered subchannels. */
 139         if (fn_unknown)
 140                 rc = for_each_subchannel(call_fn_unknown_sch, &cb);
 141 out:
 142         idset_free(cb.set);
 143
 144         return rc;
 145 }
 146
 147 static void css_sch_todo(struct work_struct *work);
 148
 149 static int css_sch_create_locks(struct subchannel *sch)
 150 {
 151         sch->lock = kmalloc(sizeof(*sch->lock), GFP_KERNEL);
 152         if (!sch->lock)
 153                 return -ENOMEM;
 154
 155         spin_lock_init(sch->lock);
 156         mutex_init(&sch->reg_mutex);
 157
 158         return 0;
 159 }
 160
 161 static void css_subchannel_release(struct device *dev)
 162 {
 163         struct subchannel *sch = to_subchannel(dev);
 164
 165         sch->config.intparm = 0;
 166         cio_commit_config(sch);
 167         kfree(sch->lock);
 168         kfree(sch);
 169 }
 170
 171 struct subchannel *css_alloc_subchannel(struct subchannel_id schid)
 172 {
 173         struct subchannel *sch;
 174         int ret;
 175
 176         sch = kzalloc(sizeof(*sch), GFP_KERNEL | GFP_DMA);
 177         if (!sch)
 178                 return ERR_PTR(-ENOMEM);
 179
 180         ret = cio_validate_subchannel(sch, schid);
 181         if (ret < 0)
 182                 goto err;
 183
 184         ret = css_sch_create_locks(sch);
 185         if (ret)
 186                 goto err;
 187
 188         INIT_WORK(&sch->todo_work, css_sch_todo);
 189         sch->dev.release = &css_subchannel_release;
 190         device_initialize(&sch->dev);
 191         return sch;
 192
 193 err:
 194         kfree(sch);
 195         return ERR_PTR(ret);
 196 }
 197
 198 static int css_sch_device_register(struct subchannel *sch)
 199 {
 200         int ret;
 201
 202         mutex_lock(&sch->reg_mutex);
 203         dev_set_name(&sch->dev, "0.%x.%04x", sch->schid.ssid,
 204                      sch->schid.sch_no);
 205         ret = device_add(&sch->dev);
 206         mutex_unlock(&sch->reg_mutex);
 207         return ret;
 208 }
 209
 210 /**
 211  * css_sch_device_unregister - unregister a subchannel
 212  * @sch: subchannel to be unregistered
 213  */
 214 void css_sch_device_unregister(struct subchannel *sch)
 215 {
 216         mutex_lock(&sch->reg_mutex);
 217         if (device_is_registered(&sch->dev))
 218                 device_unregister(&sch->dev);
 219         mutex_unlock(&sch->reg_mutex);
 220 }
 221 EXPORT_SYMBOL_GPL(css_sch_device_unregister);
 222
 223 static void ssd_from_pmcw(struct chsc_ssd_info *ssd, struct pmcw *pmcw)
 224 {
 225         int i;
 226         int mask;
 227
 228         memset(ssd, 0, sizeof(struct chsc_ssd_info));
 229         ssd->path_mask = pmcw->pim;
 230         for (i = 0; i < 8; i++) {
 231                 mask = 0x80 >> i;
 232                 if (pmcw->pim & mask) {
 233                         chp_id_init(&ssd->chpid[i]);
 234                         ssd->chpid[i].id = pmcw->chpid[i];
 235                 }
 236         }
 237 }
 238
 239 static void ssd_register_chpids(struct chsc_ssd_info *ssd)
 240 {
 241         int i;
 242         int mask;
 243
 244         for (i = 0; i < 8; i++) {
 245                 mask = 0x80 >> i;
 246                 if (ssd->path_mask & mask)
 247                         if (!chp_is_registered(ssd->chpid[i]))
 248                                 chp_new(ssd->chpid[i]);
 249         }
 250 }
 251
 252 void css_update_ssd_info(struct subchannel *sch)
 253 {
 254         int ret;
 255
 256         ret = chsc_get_ssd_info(sch->schid, &sch->ssd_info);
 257         if (ret)
 258                 ssd_from_pmcw(&sch->ssd_info, &sch->schib.pmcw);
 259
 260         ssd_register_chpids(&sch->ssd_info);
 261 }
 262
 263 static ssize_t type_show(struct device *dev, struct device_attribute *attr,
 264                          char *buf)
 265 {
 266         struct subchannel *sch = to_subchannel(dev);
 267
 268         return sprintf(buf, "%01x\n", sch->st);
 269 }
 270
 271 static DEVICE_ATTR(type, 0444, type_show, NULL);
 272
 273 static ssize_t modalias_show(struct device *dev, struct device_attribute *attr,
 274                              char *buf)
 275 {
 276         struct subchannel *sch = to_subchannel(dev);
 277
 278         return sprintf(buf, "css:t%01X\n", sch->st);
 279 }
 280
 281 static DEVICE_ATTR(modalias, 0444, modalias_show, NULL);
 282
 283 static struct attribute *subch_attrs[] = {
 284         &dev_attr_type.attr,
 285         &dev_attr_modalias.attr,
 286         NULL,
 287 };
 288
 289 static struct attribute_group subch_attr_group = {
 290         .attrs = subch_attrs,
 291 };
 292
 293 static const struct attribute_group *default_subch_attr_groups[] = {
 294         &subch_attr_group,
 295         NULL,
 296 };
 297
 298 static ssize_t chpids_show(struct device *dev,
 299                            struct device_attribute *attr,
 300                            char *buf)
 301 {
 302         struct subchannel *sch = to_subchannel(dev);
 303         struct chsc_ssd_info *ssd = &sch->ssd_info;
 304         ssize_t ret = 0;
 305         int mask;
 306         int chp;
 307
 308         for (chp = 0; chp < 8; chp++) {
 309                 mask = 0x80 >> chp;
 310                 if (ssd->path_mask & mask)
 311                         ret += sprintf(buf + ret, "%02x ", ssd->chpid[chp].id);
 312                 else
 313                         ret += sprintf(buf + ret, "00 ");
 314         }
 315         ret += sprintf(buf + ret, "\n");
 316         return ret;
 317 }
 318 static DEVICE_ATTR(chpids, 0444, chpids_show, NULL);
 319
 320 static ssize_t pimpampom_show(struct device *dev,
 321                               struct device_attribute *attr,
 322                               char *buf)
 323 {
 324         struct subchannel *sch = to_subchannel(dev);
 325         struct pmcw *pmcw = &sch->schib.pmcw;
 326
 327         return sprintf(buf, "%02x %02x %02x\n",
 328                        pmcw->pim, pmcw->pam, pmcw->pom);
 329 }
 330 static DEVICE_ATTR(pimpampom, 0444, pimpampom_show, NULL);
 331
 332 static struct attribute *io_subchannel_type_attrs[] = {
 333         &dev_attr_chpids.attr,
 334         &dev_attr_pimpampom.attr,
 335         NULL,
 336 };
 337 ATTRIBUTE_GROUPS(io_subchannel_type);
 338
 339 static const struct device_type io_subchannel_type = {
 340         .groups = io_subchannel_type_groups,
 341 };
 342
 343 int css_register_subchannel(struct subchannel *sch)
 344 {
 345         int ret;
 346
 347         /* Initialize the subchannel structure */
 348         sch->dev.parent = &channel_subsystems[0]->device;
 349         sch->dev.bus = &css_bus_type;
 350         sch->dev.groups = default_subch_attr_groups;
 351
 352         if (sch->st == SUBCHANNEL_TYPE_IO)
 353                 sch->dev.type = &io_subchannel_type;
 354
 355         /*
 356          * We don't want to generate uevents for I/O subchannels that don't
 357          * have a working ccw device behind them since they will be
 358          * unregistered before they can be used anyway, so we delay the add
 359          * uevent until after device recognition was successful.
 360          * Note that we suppress the uevent for all subchannel types;
 361          * the subchannel driver can decide itself when it wants to inform
 362          * userspace of its existence.
 363          */
 364         dev_set_uevent_suppress(&sch->dev, 1);
 365         css_update_ssd_info(sch);
 366         /* make it known to the system */
 367         ret = css_sch_device_register(sch);
 368         if (ret) {
 369                 CIO_MSG_EVENT(0, "Could not register sch 0.%x.%04x: %d\n",
 370                               sch->schid.ssid, sch->schid.sch_no, ret);
 371                 return ret;
 372         }
 373         if (!sch->driver) {
 374                 /*
 375                  * No driver matched. Generate the uevent now so that
 376                  * a fitting driver module may be loaded based on the
 377                  * modalias.
 378                  */
 379                 dev_set_uevent_suppress(&sch->dev, 0);
 380                 kobject_uevent(&sch->dev.kobj, KOBJ_ADD);
 381         }
 382         return ret;
 383 }
 384
 385 static int css_probe_device(struct subchannel_id schid)
 386 {
 387         struct subchannel *sch;
 388         int ret;
 389
 390         sch = css_alloc_subchannel(schid);
 391         if (IS_ERR(sch))
 392                 return PTR_ERR(sch);
 393
 394         ret = css_register_subchannel(sch);
 395         if (ret)
 396                 put_device(&sch->dev);
 397
 398         return ret;
 399 }
 400
 401 static int
 402 check_subchannel(struct device * dev, void * data)
 403 {
 404         struct subchannel *sch;
 405         struct subchannel_id *schid = data;
 406
 407         sch = to_subchannel(dev);
 408         return schid_equal(&sch->schid, schid);
 409 }
 410
 411 struct subchannel *
 412 get_subchannel_by_schid(struct subchannel_id schid)
 413 {
 414         struct device *dev;
 415
 416         dev = bus_find_device(&css_bus_type, NULL,
 417                               &schid, check_subchannel);
 418
 419         return dev ? to_subchannel(dev) : NULL;
 420 }
 421
 422 /**
 423  * css_sch_is_valid() - check if a subchannel is valid
 424  * @schib: subchannel information block for the subchannel
 425  */
 426 int css_sch_is_valid(struct schib *schib)
 427 {
 428         if ((schib->pmcw.st == SUBCHANNEL_TYPE_IO) && !schib->pmcw.dnv)
 429                 return 0;
 430         if ((schib->pmcw.st == SUBCHANNEL_TYPE_MSG) && !schib->pmcw.w)
 431                 return 0;
 432         return 1;
 433 }
 434 EXPORT_SYMBOL_GPL(css_sch_is_valid);
 435
 436 static int css_evaluate_new_subchannel(struct subchannel_id schid, int slow)
 437 {
 438         struct schib schib;
 439
 440         if (!slow) {
 441                 /* Will be done on the slow path. */
 442                 return -EAGAIN;
 443         }
 444         if (stsch(schid, &schib)) {
 445                 /* Subchannel is not provided. */
 446                 return -ENXIO;
 447         }
 448         if (!css_sch_is_valid(&schib)) {
 449                 /* Unusable - ignore. */
 450                 return 0;
 451         }
 452         CIO_MSG_EVENT(4, "event: sch 0.%x.%04x, new\n", schid.ssid,
 453                       schid.sch_no);
 454
 455         return css_probe_device(schid);
 456 }
 457
 458 static int css_evaluate_known_subchannel(struct subchannel *sch, int slow)
 459 {
 460         int ret = 0;
 461
 462         if (sch->driver) {
 463                 if (sch->driver->sch_event)
 464                         ret = sch->driver->sch_event(sch, slow);
 465                 else
 466                         dev_dbg(&sch->dev,
 467                                 "Got subchannel machine check but "
 468                                 "no sch_event handler provided.\n");
 469         }
 470         if (ret != 0 && ret != -EAGAIN) {
 471                 CIO_MSG_EVENT(2, "eval: sch 0.%x.%04x, rc=%d\n",
 472                               sch->schid.ssid, sch->schid.sch_no, ret);
 473         }
 474         return ret;
 475 }
 476
 477 static void css_evaluate_subchannel(struct subchannel_id schid, int slow)
 478 {
 479         struct subchannel *sch;
 480         int ret;
 481
 482         sch = get_subchannel_by_schid(schid);
 483         if (sch) {
 484                 ret = css_evaluate_known_subchannel(sch, slow);
 485                 put_device(&sch->dev);
 486         } else
 487                 ret = css_evaluate_new_subchannel(schid, slow);
 488         if (ret == -EAGAIN)
 489                 css_schedule_eval(schid);
 490 }
 491
 492 /**
 493  * css_sched_sch_todo - schedule a subchannel operation
 494  * @sch: subchannel
 495  * @todo: todo
 496  *
 497  * Schedule the operation identified by @todo to be performed on the slow path
 498  * workqueue. Do nothing if another operation with higher priority is already
 499  * scheduled. Needs to be called with subchannel lock held.
 500  */
 501 void css_sched_sch_todo(struct subchannel *sch, enum sch_todo todo)
 502 {
 503         CIO_MSG_EVENT(4, "sch_todo: sched sch=0.%x.%04x todo=%d\n",
 504                       sch->schid.ssid, sch->schid.sch_no, todo);
 505         if (sch->todo >= todo)
 506                 return;
 507         /* Get workqueue ref. */
 508         if (!get_device(&sch->dev))
 509                 return;
 510         sch->todo = todo;
 511         if (!queue_work(cio_work_q, &sch->todo_work)) {
 512                 /* Already queued, release workqueue ref. */
 513                 put_device(&sch->dev);
 514         }
 515 }
 516 EXPORT_SYMBOL_GPL(css_sched_sch_todo);
 517
 518 static void css_sch_todo(struct work_struct *work)
 519 {
 520         struct subchannel *sch;
 521         enum sch_todo todo;
 522         int ret;
 523
 524         sch = container_of(work, struct subchannel, todo_work);
 525         /* Find out todo. */
 526         spin_lock_irq(sch->lock);
 527         todo = sch->todo;
 528         CIO_MSG_EVENT(4, "sch_todo: sch=0.%x.%04x, todo=%d\n", sch->schid.ssid,
 529                       sch->schid.sch_no, todo);
 530         sch->todo = SCH_TODO_NOTHING;
 531         spin_unlock_irq(sch->lock);
 532         /* Perform todo. */
 533         switch (todo) {
 534         case SCH_TODO_NOTHING:
 535                 break;
 536         case SCH_TODO_EVAL:
 537                 ret = css_evaluate_known_subchannel(sch, 1);
 538                 if (ret == -EAGAIN) {
 539                         spin_lock_irq(sch->lock);
 540                         css_sched_sch_todo(sch, todo);
 541                         spin_unlock_irq(sch->lock);
 542                 }
 543                 break;
 544         case SCH_TODO_UNREG:
 545                 css_sch_device_unregister(sch);
 546                 break;
 547         }
 548         /* Release workqueue ref. */
 549         put_device(&sch->dev);
 550 }
 551
 552 static struct idset *slow_subchannel_set;
 553 static spinlock_t slow_subchannel_lock;
 554 static wait_queue_head_t css_eval_wq;
 555 static atomic_t css_eval_scheduled;
 556
 557 static int __init slow_subchannel_init(void)
 558 {
 559         spin_lock_init(&slow_subchannel_lock);
 560         atomic_set(&css_eval_scheduled, 0);
 561         init_waitqueue_head(&css_eval_wq);
 562         slow_subchannel_set = idset_sch_new();
 563         if (!slow_subchannel_set) {
 564                 CIO_MSG_EVENT(0, "could not allocate slow subchannel set\n");
 565                 return -ENOMEM;
 566         }
 567         return 0;
 568 }
 569
 570 static int slow_eval_known_fn(struct subchannel *sch, void *data)
 571 {
 572         int eval;
 573         int rc;
 574
 575         spin_lock_irq(&slow_subchannel_lock);
 576         eval = idset_sch_contains(slow_subchannel_set, sch->schid);
 577         idset_sch_del(slow_subchannel_set, sch->schid);
 578         spin_unlock_irq(&slow_subchannel_lock);
 579         if (eval) {
 580                 rc = css_evaluate_known_subchannel(sch, 1);
 581                 if (rc == -EAGAIN)
 582                         css_schedule_eval(sch->schid);
 583         }
 584         return 0;
 585 }
 586
 587 static int slow_eval_unknown_fn(struct subchannel_id schid, void *data)
 588 {
 589         int eval;
 590         int rc = 0;
 591
 592         spin_lock_irq(&slow_subchannel_lock);
 593         eval = idset_sch_contains(slow_subchannel_set, schid);
 594         idset_sch_del(slow_subchannel_set, schid);
 595         spin_unlock_irq(&slow_subchannel_lock);
 596         if (eval) {
 597                 rc = css_evaluate_new_subchannel(schid, 1);
 598                 switch (rc) {
 599                 case -EAGAIN:
 600                         css_schedule_eval(schid);
 601                         rc = 0;
 602                         break;
 603                 case -ENXIO:
 604                 case -ENOMEM:
 605                 case -EIO:
 606                         /* These should abort looping */
 607                         spin_lock_irq(&slow_subchannel_lock);
 608                         idset_sch_del_subseq(slow_subchannel_set, schid);
 609                         spin_unlock_irq(&slow_subchannel_lock);
 610                         break;
 611                 default:
 612                         rc = 0;
 613                 }
 614                 /* Allow scheduling here since the containing loop might
 615                  * take a while.  */
 616                 cond_resched();
 617         }
 618         return rc;
 619 }
 620
 621 static void css_slow_path_func(struct work_struct *unused)
 622 {
 623         unsigned long flags;
 624
 625         CIO_TRACE_EVENT(4, "slowpath");
 626         for_each_subchannel_staged(slow_eval_known_fn, slow_eval_unknown_fn,
 627                                    NULL);
 628         spin_lock_irqsave(&slow_subchannel_lock, flags);
 629         if (idset_is_empty(slow_subchannel_set)) {
 630                 atomic_set(&css_eval_scheduled, 0);
 631                 wake_up(&css_eval_wq);
 632         }
 633         spin_unlock_irqrestore(&slow_subchannel_lock, flags);
 634 }
 635
 636 static DECLARE_DELAYED_WORK(slow_path_work, css_slow_path_func);
 637 struct workqueue_struct *cio_work_q;
 638
 639 void css_schedule_eval(struct subchannel_id schid)
 640 {
 641         unsigned long flags;
 642
 643         spin_lock_irqsave(&slow_subchannel_lock, flags);
 644         idset_sch_add(slow_subchannel_set, schid);
 645         atomic_set(&css_eval_scheduled, 1);
 646         queue_delayed_work(cio_work_q, &slow_path_work, 0);
 647         spin_unlock_irqrestore(&slow_subchannel_lock, flags);
 648 }
 649
 650 void css_schedule_eval_all(void)
 651 {
 652         unsigned long flags;
 653
 654         spin_lock_irqsave(&slow_subchannel_lock, flags);
 655         idset_fill(slow_subchannel_set);
 656         atomic_set(&css_eval_scheduled, 1);
 657         queue_delayed_work(cio_work_q, &slow_path_work, 0);
 658         spin_unlock_irqrestore(&slow_subchannel_lock, flags);
 659 }
 660
 661 static int __unset_registered(struct device *dev, void *data)
 662 {
 663         struct idset *set = data;
 664         struct subchannel *sch = to_subchannel(dev);
 665
 666         idset_sch_del(set, sch->schid);
 667         return 0;
 668 }
 669
 670 void css_schedule_eval_all_unreg(unsigned long delay)
 671 {
 672         unsigned long flags;
 673         struct idset *unreg_set;
 674
 675         /* Find unregistered subchannels. */
 676         unreg_set = idset_sch_new();
 677         if (!unreg_set) {
 678                 /* Fallback. */
 679                 css_schedule_eval_all();
 680                 return;
 681         }
 682         idset_fill(unreg_set);
 683         bus_for_each_dev(&css_bus_type, NULL, unreg_set, __unset_registered);
 684         /* Apply to slow_subchannel_set. */
 685         spin_lock_irqsave(&slow_subchannel_lock, flags);
 686         idset_add_set(slow_subchannel_set, unreg_set);
 687         atomic_set(&css_eval_scheduled, 1);
 688         queue_delayed_work(cio_work_q, &slow_path_work, delay);
 689         spin_unlock_irqrestore(&slow_subchannel_lock, flags);
 690         idset_free(unreg_set);
 691 }
 692
 693 void css_wait_for_slow_path(void)
 694 {
 695         flush_workqueue(cio_work_q);
 696 }
 697
 698 /* Schedule reprobing of all unregistered subchannels. */
 699 void css_schedule_reprobe(void)
 700 {
 701         /* Schedule with a delay to allow merging of subsequent calls. */
 702         css_schedule_eval_all_unreg(1 * HZ);
 703 }
 704 EXPORT_SYMBOL_GPL(css_schedule_reprobe);
 705
 706 /*
 707  * Called from the machine check handler for subchannel report words.
 708  */
 709 static void css_process_crw(struct crw *crw0, struct crw *crw1, int overflow)
 710 {
 711         struct subchannel_id mchk_schid;
 712         struct subchannel *sch;
 713
 714         if (overflow) {
 715                 css_schedule_eval_all();
 716                 return;
 717         }
 718         CIO_CRW_EVENT(2, "CRW0 reports slct=%d, oflw=%d, "
 719                       "chn=%d, rsc=%X, anc=%d, erc=%X, rsid=%X\n",
 720                       crw0->slct, crw0->oflw, crw0->chn, crw0->rsc, crw0->anc,
 721                       crw0->erc, crw0->rsid);
 722         if (crw1)
 723                 CIO_CRW_EVENT(2, "CRW1 reports slct=%d, oflw=%d, "
 724                               "chn=%d, rsc=%X, anc=%d, erc=%X, rsid=%X\n",
 725                               crw1->slct, crw1->oflw, crw1->chn, crw1->rsc,
 726                               crw1->anc, crw1->erc, crw1->rsid);
 727         init_subchannel_id(&mchk_schid);
 728         mchk_schid.sch_no = crw0->rsid;
 729         if (crw1)
 730                 mchk_schid.ssid = (crw1->rsid >> 4) & 3;
 731
 732         if (crw0->erc == CRW_ERC_PMOD) {
 733                 sch = get_subchannel_by_schid(mchk_schid);
 734                 if (sch) {
 735                         css_update_ssd_info(sch);
 736                         put_device(&sch->dev);
 737                 }
 738         }
 739         /*
 740          * Since we are always presented with IPI in the CRW, we have to
 741          * use stsch() to find out if the subchannel in question has come
 742          * or gone.
 743          */
 744         css_evaluate_subchannel(mchk_schid, 0);
 745 }
 746
 747 static void __init
 748 css_generate_pgid(struct channel_subsystem *css, u32 tod_high)
 749 {
 750         struct cpuid cpu_id;
 751
 752         if (css_general_characteristics.mcss) {
 753                 css->global_pgid.pgid_high.ext_cssid.version = 0x80;
 754                 css->global_pgid.pgid_high.ext_cssid.cssid =
 755                         (css->cssid < 0) ? 0 : css->cssid;
 756         } else {
 757                 css->global_pgid.pgid_high.cpu_addr = stap();
 758         }
 759         get_cpu_id(&cpu_id);
 760         css->global_pgid.cpu_id = cpu_id.ident;
 761         css->global_pgid.cpu_model = cpu_id.machine;
 762         css->global_pgid.tod_high = tod_high;
 763 }
 764
 765 static void channel_subsystem_release(struct device *dev)
 766 {
 767         struct channel_subsystem *css = to_css(dev);
 768
 769         mutex_destroy(&css->mutex);
 770         kfree(css);
 771 }
 772
 773 static ssize_t real_cssid_show(struct device *dev, struct device_attribute *a,
 774                                char *buf)
 775 {
 776         struct channel_subsystem *css = to_css(dev);
 777
 778         if (css->cssid < 0)
 779                 return -EINVAL;
 780
 781         return sprintf(buf, "%x\n", css->cssid);
 782 }
 783 static DEVICE_ATTR_RO(real_cssid);
 784
 785 static ssize_t cm_enable_show(struct device *dev, struct device_attribute *a,
 786                               char *buf)
 787 {
 788         struct channel_subsystem *css = to_css(dev);
 789         int ret;
 790
 791         mutex_lock(&css->mutex);
 792         ret = sprintf(buf, "%x\n", css->cm_enabled);
 793         mutex_unlock(&css->mutex);
 794         return ret;
 795 }
 796
 797 static ssize_t cm_enable_store(struct device *dev, struct device_attribute *a,
 798                                const char *buf, size_t count)
 799 {
 800         struct channel_subsystem *css = to_css(dev);
 801         unsigned long val;
 802         int ret;
 803
 804         ret = kstrtoul(buf, 16, &val);
 805         if (ret)
 806                 return ret;
 807         mutex_lock(&css->mutex);
 808         switch (val) {
 809         case 0:
 810                 ret = css->cm_enabled ? chsc_secm(css, 0) : 0;
 811                 break;
 812         case 1:
 813                 ret = css->cm_enabled ? 0 : chsc_secm(css, 1);
 814                 break;
 815         default:
 816                 ret = -EINVAL;
 817         }
 818         mutex_unlock(&css->mutex);
 819         return ret < 0 ? ret : count;
 820 }
 821 static DEVICE_ATTR_RW(cm_enable);
 822
 823 static umode_t cm_enable_mode(struct kobject *kobj, struct attribute *attr,
 824                               int index)
 825 {
 826         return css_chsc_characteristics.secm ? attr->mode : 0;
 827 }
 828
 829 static struct attribute *cssdev_attrs[] = {
 830         &dev_attr_real_cssid.attr,
 831         NULL,
 832 };
 833
 834 static struct attribute_group cssdev_attr_group = {
 835         .attrs = cssdev_attrs,
 836 };
 837
 838 static struct attribute *cssdev_cm_attrs[] = {
 839         &dev_attr_cm_enable.attr,
 840         NULL,
 841 };
 842
 843 static struct attribute_group cssdev_cm_attr_group = {
 844         .attrs = cssdev_cm_attrs,
 845         .is_visible = cm_enable_mode,
 846 };
 847
 848 static const struct attribute_group *cssdev_attr_groups[] = {
 849         &cssdev_attr_group,
 850         &cssdev_cm_attr_group,
 851         NULL,
 852 };
 853
 854 static int __init setup_css(int nr)
 855 {
 856         struct channel_subsystem *css;
 857         int ret;
 858
 859         css = kzalloc(sizeof(*css), GFP_KERNEL);
 860         if (!css)
 861                 return -ENOMEM;
 862
 863         channel_subsystems[nr] = css;
 864         dev_set_name(&css->device, "css%x", nr);
 865         css->device.groups = cssdev_attr_groups;
 866         css->device.release = channel_subsystem_release;
 867
 868         mutex_init(&css->mutex);
 869         css->cssid = chsc_get_cssid(nr);
 870         css_generate_pgid(css, (u32) (get_tod_clock() >> 32));
 871
 872         ret = device_register(&css->device);
 873         if (ret) {
 874                 put_device(&css->device);
 875                 goto out_err;
 876         }
 877
 878         css->pseudo_subchannel = kzalloc(sizeof(*css->pseudo_subchannel),
 879                                          GFP_KERNEL);
 880         if (!css->pseudo_subchannel) {
 881                 device_unregister(&css->device);
 882                 ret = -ENOMEM;
 883                 goto out_err;
 884         }
 885
 886         css->pseudo_subchannel->dev.parent = &css->device;
 887         css->pseudo_subchannel->dev.release = css_subchannel_release;
 888         mutex_init(&css->pseudo_subchannel->reg_mutex);
 889         ret = css_sch_create_locks(css->pseudo_subchannel);
 890         if (ret) {
 891                 kfree(css->pseudo_subchannel);
 892                 device_unregister(&css->device);
 893                 goto out_err;
 894         }
 895
 896         dev_set_name(&css->pseudo_subchannel->dev, "defunct");
 897         ret = device_register(&css->pseudo_subchannel->dev);
 898         if (ret) {
 899                 put_device(&css->pseudo_subchannel->dev);
 900                 device_unregister(&css->device);
 901                 goto out_err;
 902         }
 903
 904         return ret;
 905 out_err:
 906         channel_subsystems[nr] = NULL;
 907         return ret;
 908 }
 909
 910 static int css_reboot_event(struct notifier_block *this,
 911                             unsigned long event,
 912                             void *ptr)
 913 {
 914         struct channel_subsystem *css;
 915         int ret;
 916
 917         ret = NOTIFY_DONE;
 918         for_each_css(css) {
 919                 mutex_lock(&css->mutex);
 920                 if (css->cm_enabled)
 921                         if (chsc_secm(css, 0))
 922                                 ret = NOTIFY_BAD;
 923                 mutex_unlock(&css->mutex);
 924         }
 925
 926         return ret;
 927 }
 928
 929 static struct notifier_block css_reboot_notifier = {
 930         .notifier_call = css_reboot_event,
 931 };
 932
 933 /*
 934  * Since the css devices are neither on a bus nor have a class
 935  * nor have a special device type, we cannot stop/restart channel
 936  * path measurements via the normal suspend/resume callbacks, but have
 937  * to use notifiers.
 938  */
 939 static int css_power_event(struct notifier_block *this, unsigned long event,
 940                            void *ptr)
 941 {
 942         struct channel_subsystem *css;
 943         int ret;
 944
 945         switch (event) {
 946         case PM_HIBERNATION_PREPARE:
 947         case PM_SUSPEND_PREPARE:
 948                 ret = NOTIFY_DONE;
 949                 for_each_css(css) {
 950                         mutex_lock(&css->mutex);
 951                         if (!css->cm_enabled) {
 952                                 mutex_unlock(&css->mutex);
 953                                 continue;
 954                         }
 955                         ret = __chsc_do_secm(css, 0);
 956                         ret = notifier_from_errno(ret);
 957                         mutex_unlock(&css->mutex);
 958                 }
 959                 break;
 960         case PM_POST_HIBERNATION:
 961         case PM_POST_SUSPEND:
 962                 ret = NOTIFY_DONE;
 963                 for_each_css(css) {
 964                         mutex_lock(&css->mutex);
 965                         if (!css->cm_enabled) {
 966                                 mutex_unlock(&css->mutex);
 967                                 continue;
 968                         }
 969                         ret = __chsc_do_secm(css, 1);
 970                         ret = notifier_from_errno(ret);
 971                         mutex_unlock(&css->mutex);
 972                 }
 973                 /* search for subchannels, which appeared during hibernation */
 974                 css_schedule_reprobe();
 975                 break;
 976         default:
 977                 ret = NOTIFY_DONE;
 978         }
 979         return ret;
 980
 981 }
 982 static struct notifier_block css_power_notifier = {
 983         .notifier_call = css_power_event,
 984 };
 985
 986 /*
 987  * Now that the driver core is running, we can setup our channel subsystem.
 988  * The struct subchannel's are created during probing.
 989  */
 990 static int __init css_bus_init(void)
 991 {
 992         int ret, i;
 993
 994         ret = chsc_init();
 995         if (ret)
 996                 return ret;
 997
 998         chsc_determine_css_characteristics();
 999         /* Try to enable MSS. */
1000         ret = chsc_enable_facility(CHSC_SDA_OC_MSS);
1001         if (ret)
1002                 max_ssid = 0;
1003         else /* Success. */
1004                 max_ssid = __MAX_SSID;
1005
1006         ret = slow_subchannel_init();
1007         if (ret)
1008                 goto out;
1009
1010         ret = crw_register_handler(CRW_RSC_SCH, css_process_crw);
1011         if (ret)
1012                 goto out;
1013
1014         if ((ret = bus_register(&css_bus_type)))
1015                 goto out;
1016
1017         /* Setup css structure. */
1018         for (i = 0; i <= MAX_CSS_IDX; i++) {
1019                 ret = setup_css(i);
1020                 if (ret)
1021                         goto out_unregister;
1022         }
1023         ret = register_reboot_notifier(&css_reboot_notifier);
1024         if (ret)
1025                 goto out_unregister;
1026         ret = register_pm_notifier(&css_power_notifier);
1027         if (ret) {
1028                 unregister_reboot_notifier(&css_reboot_notifier);
1029                 goto out_unregister;
1030         }
1031         css_init_done = 1;
1032
1033         /* Enable default isc for I/O subchannels. */
1034         isc_register(IO_SCH_ISC);
1035
1036         return 0;
1037 out_unregister:
1038         while (i-- > 0) {
1039                 struct channel_subsystem *css = channel_subsystems[i];
1040                 device_unregister(&css->pseudo_subchannel->dev);
1041                 device_unregister(&css->device);
1042         }
1043         bus_unregister(&css_bus_type);
1044 out:
1045         crw_unregister_handler(CRW_RSC_SCH);
1046         idset_free(slow_subchannel_set);
1047         chsc_init_cleanup();
1048         pr_alert("The CSS device driver initialization failed with "
1049                  "errno=%d\n", ret);
1050         return ret;
1051 }
1052
1053 static void __init css_bus_cleanup(void)
1054 {
1055         struct channel_subsystem *css;
1056
1057         for_each_css(css) {
1058                 device_unregister(&css->pseudo_subchannel->dev);
1059                 device_unregister(&css->device);
1060         }
1061         bus_unregister(&css_bus_type);
1062         crw_unregister_handler(CRW_RSC_SCH);
1063         idset_free(slow_subchannel_set);
1064         chsc_init_cleanup();
1065         isc_unregister(IO_SCH_ISC);
1066 }
1067
1068 static int __init channel_subsystem_init(void)
1069 {
1070         int ret;
1071
1072         ret = css_bus_init();
1073         if (ret)
1074                 return ret;
1075         cio_work_q = create_singlethread_workqueue("cio");
1076         if (!cio_work_q) {
1077                 ret = -ENOMEM;
1078                 goto out_bus;
1079         }
1080         ret = io_subchannel_init();
1081         if (ret)
1082                 goto out_wq;
1083
1084         return ret;
1085 out_wq:
1086         destroy_workqueue(cio_work_q);
1087 out_bus:
1088         css_bus_cleanup();
1089         return ret;
1090 }
1091 subsys_initcall(channel_subsystem_init);
1092
1093 static int css_settle(struct device_driver *drv, void *unused)
1094 {
1095         struct css_driver *cssdrv = to_cssdriver(drv);
1096
1097         if (cssdrv->settle)
1098                 return cssdrv->settle();
1099         return 0;
1100 }
1101
1102 int css_complete_work(void)
1103 {
1104         int ret;
1105
1106         /* Wait for the evaluation of subchannels to finish. */
1107         ret = wait_event_interruptible(css_eval_wq,
1108                                        atomic_read(&css_eval_scheduled) == 0);
1109         if (ret)
1110                 return -EINTR;
1111         flush_workqueue(cio_work_q);
1112         /* Wait for the subchannel type specific initialization to finish */
1113         return bus_for_each_drv(&css_bus_type, NULL, NULL, css_settle);
1114 }
1115
1116
1117 /*
1118  * Wait for the initialization of devices to finish, to make sure we are
1119  * done with our setup if the search for the root device starts.
1120  */
1121 static int __init channel_subsystem_init_sync(void)
1122 {
1123         /* Register subchannels which are already in use. */
1124         cio_register_early_subchannels();
1125         /* Start initial subchannel evaluation. */
1126         css_schedule_eval_all();
1127         css_complete_work();
1128         return 0;
1129 }
1130 subsys_initcall_sync(channel_subsystem_init_sync);
1131
1132 void channel_subsystem_reinit(void)
1133 {
1134         struct channel_path *chp;
1135         struct chp_id chpid;
1136
1137         chsc_enable_facility(CHSC_SDA_OC_MSS);
1138         chp_id_for_each(&chpid) {
1139                 chp = chpid_to_chp(chpid);
1140                 if (chp)
1141                         chp_update_desc(chp);
1142         }
1143         cmf_reactivate();
1144 }
1145
1146 #ifdef CONFIG_PROC_FS
1147 static ssize_t cio_settle_write(struct file *file, const char __user *buf,
1148                                 size_t count, loff_t *ppos)
1149 {
1150         int ret;
1151
1152         /* Handle pending CRW's. */
1153         crw_wait_for_channel_report();
1154         ret = css_complete_work();
1155
1156         return ret ? ret : count;
1157 }
1158
1159 static const struct file_operations cio_settle_proc_fops = {
1160         .open = nonseekable_open,
1161         .write = cio_settle_write,
1162         .llseek = no_llseek,
1163 };
1164
1165 static int __init cio_settle_init(void)
1166 {
1167         struct proc_dir_entry *entry;
1168
1169         entry = proc_create("cio_settle", S_IWUSR, NULL,
1170                             &cio_settle_proc_fops);
1171         if (!entry)
1172                 return -ENOMEM;
1173         return 0;
1174 }
1175 device_initcall(cio_settle_init);
1176 #endif /*CONFIG_PROC_FS*/
1177
1178 int sch_is_pseudo_sch(struct subchannel *sch)
1179 {
1180         return sch == to_css(sch->dev.parent)->pseudo_subchannel;
1181 }
1182
1183 static int css_bus_match(struct device *dev, struct device_driver *drv)
1184 {
1185         struct subchannel *sch = to_subchannel(dev);
1186         struct css_driver *driver = to_cssdriver(drv);
1187         struct css_device_id *id;
1188
1189         for (id = driver->subchannel_type; id->match_flags; id++) {
1190                 if (sch->st == id->type)
1191                         return 1;
1192         }
1193
1194         return 0;
1195 }
1196
1197 static int css_probe(struct device *dev)
1198 {
1199         struct subchannel *sch;
1200         int ret;
1201
1202         sch = to_subchannel(dev);
1203         sch->driver = to_cssdriver(dev->driver);
1204         ret = sch->driver->probe ? sch->driver->probe(sch) : 0;
1205         if (ret)
1206                 sch->driver = NULL;
1207         return ret;
1208 }
1209
1210 static int css_remove(struct device *dev)
1211 {
1212         struct subchannel *sch;
1213         int ret;
1214
1215         sch = to_subchannel(dev);
1216         ret = sch->driver->remove ? sch->driver->remove(sch) : 0;
1217         sch->driver = NULL;
1218         return ret;
1219 }
1220
1221 static void css_shutdown(struct device *dev)
1222 {
1223         struct subchannel *sch;
1224
1225         sch = to_subchannel(dev);
1226         if (sch->driver && sch->driver->shutdown)
1227                 sch->driver->shutdown(sch);
1228 }
1229
1230 static int css_uevent(struct device *dev, struct kobj_uevent_env *env)
1231 {
1232         struct subchannel *sch = to_subchannel(dev);
1233         int ret;
1234
1235         ret = add_uevent_var(env, "ST=%01X", sch->st);
1236         if (ret)
1237                 return ret;
1238         ret = add_uevent_var(env, "MODALIAS=css:t%01X", sch->st);
1239         return ret;
1240 }
1241
1242 static int css_pm_prepare(struct device *dev)
1243 {
1244         struct subchannel *sch = to_subchannel(dev);
1245         struct css_driver *drv;
1246
1247         if (mutex_is_locked(&sch->reg_mutex))
1248                 return -EAGAIN;
1249         if (!sch->dev.driver)
1250                 return 0;
1251         drv = to_cssdriver(sch->dev.driver);
1252         /* Notify drivers that they may not register children. */
1253         return drv->prepare ? drv->prepare(sch) : 0;
1254 }
1255
1256 static void css_pm_complete(struct device *dev)
1257 {
1258         struct subchannel *sch = to_subchannel(dev);
1259         struct css_driver *drv;
1260
1261         if (!sch->dev.driver)
1262                 return;
1263         drv = to_cssdriver(sch->dev.driver);
1264         if (drv->complete)
1265                 drv->complete(sch);
1266 }
1267
1268 static int css_pm_freeze(struct device *dev)
1269 {
1270         struct subchannel *sch = to_subchannel(dev);
1271         struct css_driver *drv;
1272
1273         if (!sch->dev.driver)
1274                 return 0;
1275         drv = to_cssdriver(sch->dev.driver);
1276         return drv->freeze ? drv->freeze(sch) : 0;
1277 }
1278
1279 static int css_pm_thaw(struct device *dev)
1280 {
1281         struct subchannel *sch = to_subchannel(dev);
1282         struct css_driver *drv;
1283
1284         if (!sch->dev.driver)
1285                 return 0;
1286         drv = to_cssdriver(sch->dev.driver);
1287         return drv->thaw ? drv->thaw(sch) : 0;
1288 }
1289
1290 static int css_pm_restore(struct device *dev)
1291 {
1292         struct subchannel *sch = to_subchannel(dev);
1293         struct css_driver *drv;
1294
1295         css_update_ssd_info(sch);
1296         if (!sch->dev.driver)
1297                 return 0;
1298         drv = to_cssdriver(sch->dev.driver);
1299         return drv->restore ? drv->restore(sch) : 0;
1300 }
1301
1302 static const struct dev_pm_ops css_pm_ops = {
1303         .prepare = css_pm_prepare,
1304         .complete = css_pm_complete,
1305         .freeze = css_pm_freeze,
1306         .thaw = css_pm_thaw,
1307         .restore = css_pm_restore,
1308 };
1309
1310 static struct bus_type css_bus_type = {
1311         .name     = "css",
1312         .match    = css_bus_match,
1313         .probe    = css_probe,
1314         .remove   = css_remove,
1315         .shutdown = css_shutdown,
1316         .uevent   = css_uevent,
1317         .pm = &css_pm_ops,
1318 };
1319
1320 /**
1321  * css_driver_register - register a css driver
1322  * @cdrv: css driver to register
1323  *
1324  * This is mainly a wrapper around driver_register that sets name
1325  * and bus_type in the embedded struct device_driver correctly.
1326  */
1327 int css_driver_register(struct css_driver *cdrv)
1328 {
1329         cdrv->drv.bus = &css_bus_type;
1330         return driver_register(&cdrv->drv);
1331 }
1332 EXPORT_SYMBOL_GPL(css_driver_register);
1333
1334 /**
1335  * css_driver_unregister - unregister a css driver
1336  * @cdrv: css driver to unregister
1337  *
1338  * This is a wrapper around driver_unregister.
1339  */
1340 void css_driver_unregister(struct css_driver *cdrv)
1341 {
1342         driver_unregister(&cdrv->drv);
1343 }
1344 EXPORT_SYMBOL_GPL(css_driver_unregister);