drivers/s390/cio/css.c

   1 /*
   2  *  drivers/s390/cio/css.c
   3  *  driver for channel subsystem
   4  *
   5  *    Copyright (C) 2002 IBM Deutschland Entwicklung GmbH,
   6  *                       IBM Corporation
   7  *    Author(s): Arnd Bergmann (arndb@de.ibm.com)
   8  *               Cornelia Huck (cornelia.huck@de.ibm.com)
   9  */
  10 #include <linux/module.h>
  11 #include <linux/init.h>
  12 #include <linux/device.h>
  13 #include <linux/slab.h>
  14 #include <linux/errno.h>
  15 #include <linux/list.h>
  16
  17 #include "css.h"
  18 #include "cio.h"
  19 #include "cio_debug.h"
  20 #include "ioasm.h"
  21 #include "chsc.h"
  22 #include "device.h"
  23
  24 int need_rescan = 0;
  25 int css_init_done = 0;
  26 static int need_reprobe = 0;
  27 static int max_ssid = 0;
  28
  29 struct channel_subsystem *css[__MAX_CSSID + 1];
  30
  31 int css_characteristics_avail = 0;
  32
  33 inline int
  34 for_each_subchannel(int(*fn)(struct subchannel_id, void *), void *data)
  35 {
  36         struct subchannel_id schid;
  37         int ret;
  38
  39         init_subchannel_id(&schid);
  40         ret = -ENODEV;
  41         do {
  42                 do {
  43                         ret = fn(schid, data);
  44                         if (ret)
  45                                 break;
  46                 } while (schid.sch_no++ < __MAX_SUBCHANNEL);
  47                 schid.sch_no = 0;
  48         } while (schid.ssid++ < max_ssid);
  49         return ret;
  50 }
  51
  52 static struct subchannel *
  53 css_alloc_subchannel(struct subchannel_id schid)
  54 {
  55         struct subchannel *sch;
  56         int ret;
  57
  58         sch = kmalloc (sizeof (*sch), GFP_KERNEL | GFP_DMA);
  59         if (sch == NULL)
  60                 return ERR_PTR(-ENOMEM);
  61         ret = cio_validate_subchannel (sch, schid);
  62         if (ret < 0) {
  63                 kfree(sch);
  64                 return ERR_PTR(ret);
  65         }
  66
  67         if (sch->st != SUBCHANNEL_TYPE_IO) {
  68                 /* For now we ignore all non-io subchannels. */
  69                 kfree(sch);
  70                 return ERR_PTR(-EINVAL);
  71         }
  72
  73         /*
  74          * Set intparm to subchannel address.
  75          * This is fine even on 64bit since the subchannel is always located
  76          * under 2G.
  77          */
  78         sch->schib.pmcw.intparm = (__u32)(unsigned long)sch;
  79         ret = cio_modify(sch);
  80         if (ret) {
  81                 kfree(sch);
  82                 return ERR_PTR(ret);
  83         }
  84         return sch;
  85 }
  86
  87 static void
  88 css_free_subchannel(struct subchannel *sch)
  89 {
  90         if (sch) {
  91                 /* Reset intparm to zeroes. */
  92                 sch->schib.pmcw.intparm = 0;
  93                 cio_modify(sch);
  94                 kfree(sch);
  95         }
  96
  97 }
  98
  99 static void
 100 css_subchannel_release(struct device *dev)
 101 {
 102         struct subchannel *sch;
 103
 104         sch = to_subchannel(dev);
 105         if (!cio_is_console(sch->schid))
 106                 kfree(sch);
 107 }
 108
 109 extern int css_get_ssd_info(struct subchannel *sch);
 110
 111 static int
 112 css_register_subchannel(struct subchannel *sch)
 113 {
 114         int ret;
 115
 116         /* Initialize the subchannel structure */
 117         sch->dev.parent = &css[0]->device;
 118         sch->dev.bus = &css_bus_type;
 119         sch->dev.release = &css_subchannel_release;
 120
 121         /* make it known to the system */
 122         ret = device_register(&sch->dev);
 123         if (ret)
 124                 printk (KERN_WARNING "%s: could not register %s\n",
 125                         __func__, sch->dev.bus_id);
 126         else
 127                 css_get_ssd_info(sch);
 128         return ret;
 129 }
 130
 131 int
 132 css_probe_device(struct subchannel_id schid)
 133 {
 134         int ret;
 135         struct subchannel *sch;
 136
 137         sch = css_alloc_subchannel(schid);
 138         if (IS_ERR(sch))
 139                 return PTR_ERR(sch);
 140         ret = css_register_subchannel(sch);
 141         if (ret)
 142                 css_free_subchannel(sch);
 143         return ret;
 144 }
 145
 146 static int
 147 check_subchannel(struct device * dev, void * data)
 148 {
 149         struct subchannel *sch;
 150         struct subchannel_id *schid = data;
 151
 152         sch = to_subchannel(dev);
 153         return schid_equal(&sch->schid, schid);
 154 }
 155
 156 struct subchannel *
 157 get_subchannel_by_schid(struct subchannel_id schid)
 158 {
 159         struct device *dev;
 160
 161         dev = bus_find_device(&css_bus_type, NULL,
 162                               (void *)&schid, check_subchannel);
 163
 164         return dev ? to_subchannel(dev) : NULL;
 165 }
 166
 167
 168 static inline int
 169 css_get_subchannel_status(struct subchannel *sch, struct subchannel_id schid)
 170 {
 171         struct schib schib;
 172         int cc;
 173
 174         cc = stsch(schid, &schib);
 175         if (cc)
 176                 return CIO_GONE;
 177         if (!schib.pmcw.dnv)
 178                 return CIO_GONE;
 179         if (sch && sch->schib.pmcw.dnv &&
 180             (schib.pmcw.dev != sch->schib.pmcw.dev))
 181                 return CIO_REVALIDATE;
 182         if (sch && !sch->lpm)
 183                 return CIO_NO_PATH;
 184         return CIO_OPER;
 185 }
 186
 187 static int
 188 css_evaluate_subchannel(struct subchannel_id schid, int slow)
 189 {
 190         int event, ret, disc;
 191         struct subchannel *sch;
 192         unsigned long flags;
 193
 194         sch = get_subchannel_by_schid(schid);
 195         disc = sch ? device_is_disconnected(sch) : 0;
 196         if (disc && slow) {
 197                 if (sch)
 198                         put_device(&sch->dev);
 199                 return 0; /* Already processed. */
 200         }
 201         /*
 202          * We've got a machine check, so running I/O won't get an interrupt.
 203          * Kill any pending timers.
 204          */
 205         if (sch)
 206                 device_kill_pending_timer(sch);
 207         if (!disc && !slow) {
 208                 if (sch)
 209                         put_device(&sch->dev);
 210                 return -EAGAIN; /* Will be done on the slow path. */
 211         }
 212         event = css_get_subchannel_status(sch, schid);
 213         CIO_MSG_EVENT(4, "Evaluating schid 0.%x.%04x, event %d, %s, %s path.\n",
 214                       schid.ssid, schid.sch_no, event,
 215                       sch?(disc?"disconnected":"normal"):"unknown",
 216                       slow?"slow":"fast");
 217         switch (event) {
 218         case CIO_NO_PATH:
 219         case CIO_GONE:
 220                 if (!sch) {
 221                         /* Never used this subchannel. Ignore. */
 222                         ret = 0;
 223                         break;
 224                 }
 225                 if (disc && (event == CIO_NO_PATH)) {
 226                         /*
 227                          * Uargh, hack again. Because we don't get a machine
 228                          * check on configure on, our path bookkeeping can
 229                          * be out of date here (it's fine while we only do
 230                          * logical varying or get chsc machine checks). We
 231                          * need to force reprobing or we might miss devices
 232                          * coming operational again. It won't do harm in real
 233                          * no path situations.
 234                          */
 235                         spin_lock_irqsave(&sch->lock, flags);
 236                         device_trigger_reprobe(sch);
 237                         spin_unlock_irqrestore(&sch->lock, flags);
 238                         ret = 0;
 239                         break;
 240                 }
 241                 if (sch->driver && sch->driver->notify &&
 242                     sch->driver->notify(&sch->dev, event)) {
 243                         cio_disable_subchannel(sch);
 244                         device_set_disconnected(sch);
 245                         ret = 0;
 246                         break;
 247                 }
 248                 /*
 249                  * Unregister subchannel.
 250                  * The device will be killed automatically.
 251                  */
 252                 cio_disable_subchannel(sch);
 253                 device_unregister(&sch->dev);
 254                 /* Reset intparm to zeroes. */
 255                 sch->schib.pmcw.intparm = 0;
 256                 cio_modify(sch);
 257                 put_device(&sch->dev);
 258                 ret = 0;
 259                 break;
 260         case CIO_REVALIDATE:
 261                 /*
 262                  * Revalidation machine check. Sick.
 263                  * We don't notify the driver since we have to throw the device
 264                  * away in any case.
 265                  */
 266                 if (!disc) {
 267                         device_unregister(&sch->dev);
 268                         /* Reset intparm to zeroes. */
 269                         sch->schib.pmcw.intparm = 0;
 270                         cio_modify(sch);
 271                         put_device(&sch->dev);
 272                         ret = css_probe_device(schid);
 273                 } else {
 274                         /*
 275                          * We can't immediately deregister the disconnected
 276                          * device since it might block.
 277                          */
 278                         spin_lock_irqsave(&sch->lock, flags);
 279                         device_trigger_reprobe(sch);
 280                         spin_unlock_irqrestore(&sch->lock, flags);
 281                         ret = 0;
 282                 }
 283                 break;
 284         case CIO_OPER:
 285                 if (disc) {
 286                         spin_lock_irqsave(&sch->lock, flags);
 287                         /* Get device operational again. */
 288                         device_trigger_reprobe(sch);
 289                         spin_unlock_irqrestore(&sch->lock, flags);
 290                 }
 291                 ret = sch ? 0 : css_probe_device(schid);
 292                 break;
 293         default:
 294                 BUG();
 295                 ret = 0;
 296         }
 297         return ret;
 298 }
 299
 300 static int
 301 css_rescan_devices(struct subchannel_id schid, void *data)
 302 {
 303         return css_evaluate_subchannel(schid, 1);
 304 }
 305
 306 struct slow_subchannel {
 307         struct list_head slow_list;
 308         struct subchannel_id schid;
 309 };
 310
 311 static LIST_HEAD(slow_subchannels_head);
 312 static DEFINE_SPINLOCK(slow_subchannel_lock);
 313
 314 static void
 315 css_trigger_slow_path(void)
 316 {
 317         CIO_TRACE_EVENT(4, "slowpath");
 318
 319         if (need_rescan) {
 320                 need_rescan = 0;
 321                 for_each_subchannel(css_rescan_devices, NULL);
 322                 return;
 323         }
 324
 325         spin_lock_irq(&slow_subchannel_lock);
 326         while (!list_empty(&slow_subchannels_head)) {
 327                 struct slow_subchannel *slow_sch =
 328                         list_entry(slow_subchannels_head.next,
 329                                    struct slow_subchannel, slow_list);
 330
 331                 list_del_init(slow_subchannels_head.next);
 332                 spin_unlock_irq(&slow_subchannel_lock);
 333                 css_evaluate_subchannel(slow_sch->schid, 1);
 334                 spin_lock_irq(&slow_subchannel_lock);
 335                 kfree(slow_sch);
 336         }
 337         spin_unlock_irq(&slow_subchannel_lock);
 338 }
 339
 340 typedef void (*workfunc)(void *);
 341 DECLARE_WORK(slow_path_work, (workfunc)css_trigger_slow_path, NULL);
 342 struct workqueue_struct *slow_path_wq;
 343
 344 /* Reprobe subchannel if unregistered. */
 345 static int reprobe_subchannel(struct subchannel_id schid, void *data)
 346 {
 347         struct subchannel *sch;
 348         int ret;
 349
 350         CIO_DEBUG(KERN_INFO, 6, "cio: reprobe 0.%x.%04x\n",
 351                   schid.ssid, schid.sch_no);
 352         if (need_reprobe)
 353                 return -EAGAIN;
 354
 355         sch = get_subchannel_by_schid(schid);
 356         if (sch) {
 357                 /* Already known. */
 358                 put_device(&sch->dev);
 359                 return 0;
 360         }
 361
 362         ret = css_probe_device(schid);
 363         switch (ret) {
 364         case 0:
 365                 break;
 366         case -ENXIO:
 367         case -ENOMEM:
 368                 /* These should abort looping */
 369                 break;
 370         default:
 371                 ret = 0;
 372         }
 373
 374         return ret;
 375 }
 376
 377 /* Work function used to reprobe all unregistered subchannels. */
 378 static void reprobe_all(void *data)
 379 {
 380         int ret;
 381
 382         CIO_MSG_EVENT(2, "reprobe start\n");
 383
 384         need_reprobe = 0;
 385         /* Make sure initial subchannel scan is done. */
 386         wait_event(ccw_device_init_wq,
 387                    atomic_read(&ccw_device_init_count) == 0);
 388         ret = for_each_subchannel(reprobe_subchannel, NULL);
 389
 390         CIO_MSG_EVENT(2, "reprobe done (rc=%d, need_reprobe=%d)\n", ret,
 391                       need_reprobe);
 392 }
 393
 394 DECLARE_WORK(css_reprobe_work, reprobe_all, NULL);
 395
 396 /* Schedule reprobing of all unregistered subchannels. */
 397 void css_schedule_reprobe(void)
 398 {
 399         need_reprobe = 1;
 400         queue_work(ccw_device_work, &css_reprobe_work);
 401 }
 402
 403 EXPORT_SYMBOL_GPL(css_schedule_reprobe);
 404
 405 /*
 406  * Rescan for new devices. FIXME: This is slow.
 407  * This function is called when we have lost CRWs due to overflows and we have
 408  * to do subchannel housekeeping.
 409  */
 410 void
 411 css_reiterate_subchannels(void)
 412 {
 413         css_clear_subchannel_slow_list();
 414         need_rescan = 1;
 415 }
 416
 417 /*
 418  * Called from the machine check handler for subchannel report words.
 419  */
 420 int
 421 css_process_crw(int rsid1, int rsid2)
 422 {
 423         int ret;
 424         struct subchannel_id mchk_schid;
 425
 426         CIO_CRW_EVENT(2, "source is subchannel %04X, subsystem id %x\n",
 427                       rsid1, rsid2);
 428
 429         if (need_rescan)
 430                 /* We need to iterate all subchannels anyway. */
 431                 return -EAGAIN;
 432
 433         init_subchannel_id(&mchk_schid);
 434         mchk_schid.sch_no = rsid1;
 435         if (rsid2 != 0)
 436                 mchk_schid.ssid = (rsid2 >> 8) & 3;
 437
 438         /*
 439          * Since we are always presented with IPI in the CRW, we have to
 440          * use stsch() to find out if the subchannel in question has come
 441          * or gone.
 442          */
 443         ret = css_evaluate_subchannel(mchk_schid, 0);
 444         if (ret == -EAGAIN) {
 445                 if (css_enqueue_subchannel_slow(mchk_schid)) {
 446                         css_clear_subchannel_slow_list();
 447                         need_rescan = 1;
 448                 }
 449         }
 450         return ret;
 451 }
 452
 453 static int __init
 454 __init_channel_subsystem(struct subchannel_id schid, void *data)
 455 {
 456         struct subchannel *sch;
 457         int ret;
 458
 459         if (cio_is_console(schid))
 460                 sch = cio_get_console_subchannel();
 461         else {
 462                 sch = css_alloc_subchannel(schid);
 463                 if (IS_ERR(sch))
 464                         ret = PTR_ERR(sch);
 465                 else
 466                         ret = 0;
 467                 switch (ret) {
 468                 case 0:
 469                         break;
 470                 case -ENOMEM:
 471                         panic("Out of memory in init_channel_subsystem\n");
 472                 /* -ENXIO: no more subchannels. */
 473                 case -ENXIO:
 474                         return ret;
 475                 /* -EIO: this subchannel set not supported. */
 476                 case -EIO:
 477                         return ret;
 478                 default:
 479                         return 0;
 480                 }
 481         }
 482         /*
 483          * We register ALL valid subchannels in ioinfo, even those
 484          * that have been present before init_channel_subsystem.
 485          * These subchannels can't have been registered yet (kmalloc
 486          * not working) so we do it now. This is true e.g. for the
 487          * console subchannel.
 488          */
 489         css_register_subchannel(sch);
 490         return 0;
 491 }
 492
 493 static void __init
 494 css_generate_pgid(struct channel_subsystem *css, u32 tod_high)
 495 {
 496         if (css_characteristics_avail && css_general_characteristics.mcss) {
 497                 css->global_pgid.pgid_high.ext_cssid.version = 0x80;
 498                 css->global_pgid.pgid_high.ext_cssid.cssid = css->cssid;
 499         } else {
 500 #ifdef CONFIG_SMP
 501                 css->global_pgid.pgid_high.cpu_addr = hard_smp_processor_id();
 502 #else
 503                 css->global_pgid.pgid_high.cpu_addr = 0;
 504 #endif
 505         }
 506         css->global_pgid.cpu_id = ((cpuid_t *) __LC_CPUID)->ident;
 507         css->global_pgid.cpu_model = ((cpuid_t *) __LC_CPUID)->machine;
 508         css->global_pgid.tod_high = tod_high;
 509
 510 }
 511
 512 static void
 513 channel_subsystem_release(struct device *dev)
 514 {
 515         struct channel_subsystem *css;
 516
 517         css = to_css(dev);
 518         mutex_destroy(&css->mutex);
 519         kfree(css);
 520 }
 521
 522 static ssize_t
 523 css_cm_enable_show(struct device *dev, struct device_attribute *attr,
 524                    char *buf)
 525 {
 526         struct channel_subsystem *css = to_css(dev);
 527
 528         if (!css)
 529                 return 0;
 530         return sprintf(buf, "%x\n", css->cm_enabled);
 531 }
 532
 533 static ssize_t
 534 css_cm_enable_store(struct device *dev, struct device_attribute *attr,
 535                     const char *buf, size_t count)
 536 {
 537         struct channel_subsystem *css = to_css(dev);
 538         int ret;
 539
 540         switch (buf[0]) {
 541         case '0':
 542                 ret = css->cm_enabled ? chsc_secm(css, 0) : 0;
 543                 break;
 544         case '1':
 545                 ret = css->cm_enabled ? 0 : chsc_secm(css, 1);
 546                 break;
 547         default:
 548                 ret = -EINVAL;
 549         }
 550         return ret < 0 ? ret : count;
 551 }
 552
 553 static DEVICE_ATTR(cm_enable, 0644, css_cm_enable_show, css_cm_enable_store);
 554
 555 static inline void __init
 556 setup_css(int nr)
 557 {
 558         u32 tod_high;
 559
 560         memset(css[nr], 0, sizeof(struct channel_subsystem));
 561         mutex_init(&css[nr]->mutex);
 562         css[nr]->valid = 1;
 563         css[nr]->cssid = nr;
 564         sprintf(css[nr]->device.bus_id, "css%x", nr);
 565         css[nr]->device.release = channel_subsystem_release;
 566         tod_high = (u32) (get_clock() >> 32);
 567         css_generate_pgid(css[nr], tod_high);
 568 }
 569
 570 /*
 571  * Now that the driver core is running, we can setup our channel subsystem.
 572  * The struct subchannel's are created during probing (except for the
 573  * static console subchannel).
 574  */
 575 static int __init
 576 init_channel_subsystem (void)
 577 {
 578         int ret, i;
 579
 580         if (chsc_determine_css_characteristics() == 0)
 581                 css_characteristics_avail = 1;
 582
 583         if ((ret = bus_register(&css_bus_type)))
 584                 goto out;
 585
 586         /* Try to enable MSS. */
 587         ret = chsc_enable_facility(CHSC_SDA_OC_MSS);
 588         switch (ret) {
 589         case 0: /* Success. */
 590                 max_ssid = __MAX_SSID;
 591                 break;
 592         case -ENOMEM:
 593                 goto out_bus;
 594         default:
 595                 max_ssid = 0;
 596         }
 597         /* Setup css structure. */
 598         for (i = 0; i <= __MAX_CSSID; i++) {
 599                 css[i] = kmalloc(sizeof(struct channel_subsystem), GFP_KERNEL);
 600                 if (!css[i]) {
 601                         ret = -ENOMEM;
 602                         goto out_unregister;
 603                 }
 604                 setup_css(i);
 605                 ret = device_register(&css[i]->device);
 606                 if (ret)
 607                         goto out_free;
 608                 if (css_characteristics_avail && css_chsc_characteristics.secm)
 609                         device_create_file(&css[i]->device,
 610                                            &dev_attr_cm_enable);
 611         }
 612         css_init_done = 1;
 613
 614         ctl_set_bit(6, 28);
 615
 616         for_each_subchannel(__init_channel_subsystem, NULL);
 617         return 0;
 618 out_free:
 619         kfree(css[i]);
 620 out_unregister:
 621         while (i > 0) {
 622                 i--;
 623                 if (css_characteristics_avail && css_chsc_characteristics.secm)
 624                         device_remove_file(&css[i]->device,
 625                                            &dev_attr_cm_enable);
 626                 device_unregister(&css[i]->device);
 627         }
 628 out_bus:
 629         bus_unregister(&css_bus_type);
 630 out:
 631         return ret;
 632 }
 633
 634 /*
 635  * find a driver for a subchannel. They identify by the subchannel
 636  * type with the exception that the console subchannel driver has its own
 637  * subchannel type although the device is an i/o subchannel
 638  */
 639 static int
 640 css_bus_match (struct device *dev, struct device_driver *drv)
 641 {
 642         struct subchannel *sch = container_of (dev, struct subchannel, dev);
 643         struct css_driver *driver = container_of (drv, struct css_driver, drv);
 644
 645         if (sch->st == driver->subchannel_type)
 646                 return 1;
 647
 648         return 0;
 649 }
 650
 651 static int
 652 css_probe (struct device *dev)
 653 {
 654         struct subchannel *sch;
 655
 656         sch = to_subchannel(dev);
 657         sch->driver = container_of (dev->driver, struct css_driver, drv);
 658         return (sch->driver->probe ? sch->driver->probe(sch) : 0);
 659 }
 660
 661 static int
 662 css_remove (struct device *dev)
 663 {
 664         struct subchannel *sch;
 665
 666         sch = to_subchannel(dev);
 667         return (sch->driver->remove ? sch->driver->remove(sch) : 0);
 668 }
 669
 670 static void
 671 css_shutdown (struct device *dev)
 672 {
 673         struct subchannel *sch;
 674
 675         sch = to_subchannel(dev);
 676         if (sch->driver->shutdown)
 677                 sch->driver->shutdown(sch);
 678 }
 679
 680 struct bus_type css_bus_type = {
 681         .name     = "css",
 682         .match    = css_bus_match,
 683         .probe    = css_probe,
 684         .remove   = css_remove,
 685         .shutdown = css_shutdown,
 686 };
 687
 688 subsys_initcall(init_channel_subsystem);
 689
 690 int
 691 css_enqueue_subchannel_slow(struct subchannel_id schid)
 692 {
 693         struct slow_subchannel *new_slow_sch;
 694         unsigned long flags;
 695
 696         new_slow_sch = kzalloc(sizeof(struct slow_subchannel), GFP_ATOMIC);
 697         if (!new_slow_sch)
 698                 return -ENOMEM;
 699         new_slow_sch->schid = schid;
 700         spin_lock_irqsave(&slow_subchannel_lock, flags);
 701         list_add_tail(&new_slow_sch->slow_list, &slow_subchannels_head);
 702         spin_unlock_irqrestore(&slow_subchannel_lock, flags);
 703         return 0;
 704 }
 705
 706 void
 707 css_clear_subchannel_slow_list(void)
 708 {
 709         unsigned long flags;
 710
 711         spin_lock_irqsave(&slow_subchannel_lock, flags);
 712         while (!list_empty(&slow_subchannels_head)) {
 713                 struct slow_subchannel *slow_sch =
 714                         list_entry(slow_subchannels_head.next,
 715                                    struct slow_subchannel, slow_list);
 716
 717                 list_del_init(slow_subchannels_head.next);
 718                 kfree(slow_sch);
 719         }
 720         spin_unlock_irqrestore(&slow_subchannel_lock, flags);
 721 }
 722
 723
 724
 725 int
 726 css_slow_subchannels_exist(void)
 727 {
 728         return (!list_empty(&slow_subchannels_head));
 729 }
 730
 731 MODULE_LICENSE("GPL");
 732 EXPORT_SYMBOL(css_bus_type);
 733 EXPORT_SYMBOL_GPL(css_characteristics_avail);