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