drivers/s390/cio/css.c

   1 /*
   2  *  drivers/s390/cio/css.c
   3  *  driver for channel subsystem
   4  *   $Revision: 1.85 $
   5  *
   6  *    Copyright (C) 2002 IBM Deutschland Entwicklung GmbH,
   7  *                       IBM Corporation
   8  *    Author(s): Arnd Bergmann (arndb@de.ibm.com)
   9  *               Cornelia Huck (cohuck@de.ibm.com)
  10  */
  11 #include <linux/module.h>
  12 #include <linux/init.h>
  13 #include <linux/device.h>
  14 #include <linux/slab.h>
  15 #include <linux/errno.h>
  16 #include <linux/list.h>
  17
  18 #include "css.h"
  19 #include "cio.h"
  20 #include "cio_debug.h"
  21 #include "ioasm.h"
  22 #include "chsc.h"
  23
  24 unsigned int highest_subchannel;
  25 int need_rescan = 0;
  26 int css_init_done = 0;
  27
  28 struct pgid global_pgid;
  29 int css_characteristics_avail = 0;
  30
  31 struct device css_bus_device = {
  32         .bus_id = "css0",
  33 };
  34
  35 static struct subchannel *
  36 css_alloc_subchannel(int irq)
  37 {
  38         struct subchannel *sch;
  39         int ret;
  40
  41         sch = kmalloc (sizeof (*sch), GFP_KERNEL | GFP_DMA);
  42         if (sch == NULL)
  43                 return ERR_PTR(-ENOMEM);
  44         ret = cio_validate_subchannel (sch, irq);
  45         if (ret < 0) {
  46                 kfree(sch);
  47                 return ERR_PTR(ret);
  48         }
  49         if (irq > highest_subchannel)
  50                 highest_subchannel = irq;
  51
  52         if (sch->st != SUBCHANNEL_TYPE_IO) {
  53                 /* For now we ignore all non-io subchannels. */
  54                 kfree(sch);
  55                 return ERR_PTR(-EINVAL);
  56         }
  57
  58         /*
  59          * Set intparm to subchannel address.
  60          * This is fine even on 64bit since the subchannel is always located
  61          * under 2G.
  62          */
  63         sch->schib.pmcw.intparm = (__u32)(unsigned long)sch;
  64         ret = cio_modify(sch);
  65         if (ret) {
  66                 kfree(sch);
  67                 return ERR_PTR(ret);
  68         }
  69         return sch;
  70 }
  71
  72 static void
  73 css_free_subchannel(struct subchannel *sch)
  74 {
  75         if (sch) {
  76                 /* Reset intparm to zeroes. */
  77                 sch->schib.pmcw.intparm = 0;
  78                 cio_modify(sch);
  79                 kfree(sch);
  80         }
  81
  82 }
  83
  84 static void
  85 css_subchannel_release(struct device *dev)
  86 {
  87         struct subchannel *sch;
  88
  89         sch = to_subchannel(dev);
  90         if (!cio_is_console(sch->irq))
  91                 kfree(sch);
  92 }
  93
  94 extern int css_get_ssd_info(struct subchannel *sch);
  95
  96 static int
  97 css_register_subchannel(struct subchannel *sch)
  98 {
  99         int ret;
 100
 101         /* Initialize the subchannel structure */
 102         sch->dev.parent = &css_bus_device;
 103         sch->dev.bus = &css_bus_type;
 104         sch->dev.release = &css_subchannel_release;
 105
 106         /* make it known to the system */
 107         ret = device_register(&sch->dev);
 108         if (ret)
 109                 printk (KERN_WARNING "%s: could not register %s\n",
 110                         __func__, sch->dev.bus_id);
 111         else
 112                 css_get_ssd_info(sch);
 113         return ret;
 114 }
 115
 116 int
 117 css_probe_device(int irq)
 118 {
 119         int ret;
 120         struct subchannel *sch;
 121
 122         sch = css_alloc_subchannel(irq);
 123         if (IS_ERR(sch))
 124                 return PTR_ERR(sch);
 125         ret = css_register_subchannel(sch);
 126         if (ret)
 127                 css_free_subchannel(sch);
 128         return ret;
 129 }
 130
 131 struct subchannel *
 132 get_subchannel_by_schid(int irq)
 133 {
 134         struct subchannel *sch;
 135         struct list_head *entry;
 136         struct device *dev;
 137
 138         if (!get_bus(&css_bus_type))
 139                 return NULL;
 140         down_read(&css_bus_type.subsys.rwsem);
 141         sch = NULL;
 142         list_for_each(entry, &css_bus_type.devices.list) {
 143                 dev = get_device(container_of(entry,
 144                                               struct device, bus_list));
 145                 if (!dev)
 146                         continue;
 147                 sch = to_subchannel(dev);
 148                 if (sch->irq == irq)
 149                         break;
 150                 put_device(dev);
 151                 sch = NULL;
 152         }
 153         up_read(&css_bus_type.subsys.rwsem);
 154         put_bus(&css_bus_type);
 155
 156         return sch;
 157 }
 158
 159 static inline int
 160 css_get_subchannel_status(struct subchannel *sch, int schid)
 161 {
 162         struct schib schib;
 163         int cc;
 164
 165         cc = stsch(schid, &schib);
 166         if (cc)
 167                 return CIO_GONE;
 168         if (!schib.pmcw.dnv)
 169                 return CIO_GONE;
 170         if (sch && sch->schib.pmcw.dnv &&
 171             (schib.pmcw.dev != sch->schib.pmcw.dev))
 172                 return CIO_REVALIDATE;
 173         if (sch && !sch->lpm)
 174                 return CIO_NO_PATH;
 175         return CIO_OPER;
 176 }
 177
 178 static int
 179 css_evaluate_subchannel(int irq, int slow)
 180 {
 181         int event, ret, disc;
 182         struct subchannel *sch;
 183         unsigned long flags;
 184
 185         sch = get_subchannel_by_schid(irq);
 186         disc = sch ? device_is_disconnected(sch) : 0;
 187         if (disc && slow) {
 188                 if (sch)
 189                         put_device(&sch->dev);
 190                 return 0; /* Already processed. */
 191         }
 192         /*
 193          * We've got a machine check, so running I/O won't get an interrupt.
 194          * Kill any pending timers.
 195          */
 196         if (sch)
 197                 device_kill_pending_timer(sch);
 198         if (!disc && !slow) {
 199                 if (sch)
 200                         put_device(&sch->dev);
 201                 return -EAGAIN; /* Will be done on the slow path. */
 202         }
 203         event = css_get_subchannel_status(sch, irq);
 204         CIO_MSG_EVENT(4, "Evaluating schid %04x, event %d, %s, %s path.\n",
 205                       irq, event, sch?(disc?"disconnected":"normal"):"unknown",
 206                       slow?"slow":"fast");
 207         switch (event) {
 208         case CIO_NO_PATH:
 209         case CIO_GONE:
 210                 if (!sch) {
 211                         /* Never used this subchannel. Ignore. */
 212                         ret = 0;
 213                         break;
 214                 }
 215                 if (disc && (event == CIO_NO_PATH)) {
 216                         /*
 217                          * Uargh, hack again. Because we don't get a machine
 218                          * check on configure on, our path bookkeeping can
 219                          * be out of date here (it's fine while we only do
 220                          * logical varying or get chsc machine checks). We
 221                          * need to force reprobing or we might miss devices
 222                          * coming operational again. It won't do harm in real
 223                          * no path situations.
 224                          */
 225                         spin_lock_irqsave(&sch->lock, flags);
 226                         device_trigger_reprobe(sch);
 227                         spin_unlock_irqrestore(&sch->lock, flags);
 228                         ret = 0;
 229                         break;
 230                 }
 231                 if (sch->driver && sch->driver->notify &&
 232                     sch->driver->notify(&sch->dev, event)) {
 233                         cio_disable_subchannel(sch);
 234                         device_set_disconnected(sch);
 235                         ret = 0;
 236                         break;
 237                 }
 238                 /*
 239                  * Unregister subchannel.
 240                  * The device will be killed automatically.
 241                  */
 242                 cio_disable_subchannel(sch);
 243                 device_unregister(&sch->dev);
 244                 /* Reset intparm to zeroes. */
 245                 sch->schib.pmcw.intparm = 0;
 246                 cio_modify(sch);
 247                 put_device(&sch->dev);
 248                 ret = 0;
 249                 break;
 250         case CIO_REVALIDATE:
 251                 /*
 252                  * Revalidation machine check. Sick.
 253                  * We don't notify the driver since we have to throw the device
 254                  * away in any case.
 255                  */
 256                 if (!disc) {
 257                         device_unregister(&sch->dev);
 258                         /* Reset intparm to zeroes. */
 259                         sch->schib.pmcw.intparm = 0;
 260                         cio_modify(sch);
 261                         put_device(&sch->dev);
 262                         ret = css_probe_device(irq);
 263                 } else {
 264                         /*
 265                          * We can't immediately deregister the disconnected
 266                          * device since it might block.
 267                          */
 268                         spin_lock_irqsave(&sch->lock, flags);
 269                         device_trigger_reprobe(sch);
 270                         spin_unlock_irqrestore(&sch->lock, flags);
 271                         ret = 0;
 272                 }
 273                 break;
 274         case CIO_OPER:
 275                 if (disc) {
 276                         spin_lock_irqsave(&sch->lock, flags);
 277                         /* Get device operational again. */
 278                         device_trigger_reprobe(sch);
 279                         spin_unlock_irqrestore(&sch->lock, flags);
 280                 }
 281                 ret = sch ? 0 : css_probe_device(irq);
 282                 break;
 283         default:
 284                 BUG();
 285                 ret = 0;
 286         }
 287         return ret;
 288 }
 289
 290 static void
 291 css_rescan_devices(void)
 292 {
 293         int irq, ret;
 294
 295         for (irq = 0; irq < __MAX_SUBCHANNELS; irq++) {
 296                 ret = css_evaluate_subchannel(irq, 1);
 297                 /* No more memory. It doesn't make sense to continue. No
 298                  * panic because this can happen in midflight and just
 299                  * because we can't use a new device is no reason to crash
 300                  * the system. */
 301                 if (ret == -ENOMEM)
 302                         break;
 303                 /* -ENXIO indicates that there are no more subchannels. */
 304                 if (ret == -ENXIO)
 305                         break;
 306         }
 307 }
 308
 309 struct slow_subchannel {
 310         struct list_head slow_list;
 311         unsigned long schid;
 312 };
 313
 314 static LIST_HEAD(slow_subchannels_head);
 315 static DEFINE_SPINLOCK(slow_subchannel_lock);
 316
 317 static void
 318 css_trigger_slow_path(void)
 319 {
 320         CIO_TRACE_EVENT(4, "slowpath");
 321
 322         if (need_rescan) {
 323                 need_rescan = 0;
 324                 css_rescan_devices();
 325                 return;
 326         }
 327
 328         spin_lock_irq(&slow_subchannel_lock);
 329         while (!list_empty(&slow_subchannels_head)) {
 330                 struct slow_subchannel *slow_sch =
 331                         list_entry(slow_subchannels_head.next,
 332                                    struct slow_subchannel, slow_list);
 333
 334                 list_del_init(slow_subchannels_head.next);
 335                 spin_unlock_irq(&slow_subchannel_lock);
 336                 css_evaluate_subchannel(slow_sch->schid, 1);
 337                 spin_lock_irq(&slow_subchannel_lock);
 338                 kfree(slow_sch);
 339         }
 340         spin_unlock_irq(&slow_subchannel_lock);
 341 }
 342
 343 typedef void (*workfunc)(void *);
 344 DECLARE_WORK(slow_path_work, (workfunc)css_trigger_slow_path, NULL);
 345 struct workqueue_struct *slow_path_wq;
 346
 347 /*
 348  * Rescan for new devices. FIXME: This is slow.
 349  * This function is called when we have lost CRWs due to overflows and we have
 350  * to do subchannel housekeeping.
 351  */
 352 void
 353 css_reiterate_subchannels(void)
 354 {
 355         css_clear_subchannel_slow_list();
 356         need_rescan = 1;
 357 }
 358
 359 /*
 360  * Called from the machine check handler for subchannel report words.
 361  */
 362 int
 363 css_process_crw(int irq)
 364 {
 365         int ret;
 366
 367         CIO_CRW_EVENT(2, "source is subchannel %04X\n", irq);
 368
 369         if (need_rescan)
 370                 /* We need to iterate all subchannels anyway. */
 371                 return -EAGAIN;
 372         /*
 373          * Since we are always presented with IPI in the CRW, we have to
 374          * use stsch() to find out if the subchannel in question has come
 375          * or gone.
 376          */
 377         ret = css_evaluate_subchannel(irq, 0);
 378         if (ret == -EAGAIN) {
 379                 if (css_enqueue_subchannel_slow(irq)) {
 380                         css_clear_subchannel_slow_list();
 381                         need_rescan = 1;
 382                 }
 383         }
 384         return ret;
 385 }
 386
 387 static void __init
 388 css_generate_pgid(void)
 389 {
 390         /* Let's build our path group ID here. */
 391         if (css_characteristics_avail && css_general_characteristics.mcss)
 392                 global_pgid.cpu_addr = 0x8000;
 393         else {
 394 #ifdef CONFIG_SMP
 395                 global_pgid.cpu_addr = hard_smp_processor_id();
 396 #else
 397                 global_pgid.cpu_addr = 0;
 398 #endif
 399         }
 400         global_pgid.cpu_id = ((cpuid_t *) __LC_CPUID)->ident;
 401         global_pgid.cpu_model = ((cpuid_t *) __LC_CPUID)->machine;
 402         global_pgid.tod_high = (__u32) (get_clock() >> 32);
 403 }
 404
 405 /*
 406  * Now that the driver core is running, we can setup our channel subsystem.
 407  * The struct subchannel's are created during probing (except for the
 408  * static console subchannel).
 409  */
 410 static int __init
 411 init_channel_subsystem (void)
 412 {
 413         int ret, irq;
 414
 415         if (chsc_determine_css_characteristics() == 0)
 416                 css_characteristics_avail = 1;
 417
 418         css_generate_pgid();
 419
 420         if ((ret = bus_register(&css_bus_type)))
 421                 goto out;
 422         if ((ret = device_register (&css_bus_device)))
 423                 goto out_bus;
 424
 425         css_init_done = 1;
 426
 427         ctl_set_bit(6, 28);
 428
 429         for (irq = 0; irq < __MAX_SUBCHANNELS; irq++) {
 430                 struct subchannel *sch;
 431
 432                 if (cio_is_console(irq))
 433                         sch = cio_get_console_subchannel();
 434                 else {
 435                         sch = css_alloc_subchannel(irq);
 436                         if (IS_ERR(sch))
 437                                 ret = PTR_ERR(sch);
 438                         else
 439                                 ret = 0;
 440                         if (ret == -ENOMEM)
 441                                 panic("Out of memory in "
 442                                       "init_channel_subsystem\n");
 443                         /* -ENXIO: no more subchannels. */
 444                         if (ret == -ENXIO)
 445                                 break;
 446                         if (ret)
 447                                 continue;
 448                 }
 449                 /*
 450                  * We register ALL valid subchannels in ioinfo, even those
 451                  * that have been present before init_channel_subsystem.
 452                  * These subchannels can't have been registered yet (kmalloc
 453                  * not working) so we do it now. This is true e.g. for the
 454                  * console subchannel.
 455                  */
 456                 css_register_subchannel(sch);
 457         }
 458         return 0;
 459
 460 out_bus:
 461         bus_unregister(&css_bus_type);
 462 out:
 463         return ret;
 464 }
 465
 466 /*
 467  * find a driver for a subchannel. They identify by the subchannel
 468  * type with the exception that the console subchannel driver has its own
 469  * subchannel type although the device is an i/o subchannel
 470  */
 471 static int
 472 css_bus_match (struct device *dev, struct device_driver *drv)
 473 {
 474         struct subchannel *sch = container_of (dev, struct subchannel, dev);
 475         struct css_driver *driver = container_of (drv, struct css_driver, drv);
 476
 477         if (sch->st == driver->subchannel_type)
 478                 return 1;
 479
 480         return 0;
 481 }
 482
 483 struct bus_type css_bus_type = {
 484         .name  = "css",
 485         .match = &css_bus_match,
 486 };
 487
 488 subsys_initcall(init_channel_subsystem);
 489
 490 /*
 491  * Register root devices for some drivers. The release function must not be
 492  * in the device drivers, so we do it here.
 493  */
 494 static void
 495 s390_root_dev_release(struct device *dev)
 496 {
 497         kfree(dev);
 498 }
 499
 500 struct device *
 501 s390_root_dev_register(const char *name)
 502 {
 503         struct device *dev;
 504         int ret;
 505
 506         if (!strlen(name))
 507                 return ERR_PTR(-EINVAL);
 508         dev = kmalloc(sizeof(struct device), GFP_KERNEL);
 509         if (!dev)
 510                 return ERR_PTR(-ENOMEM);
 511         memset(dev, 0, sizeof(struct device));
 512         strncpy(dev->bus_id, name, min(strlen(name), (size_t)BUS_ID_SIZE));
 513         dev->release = s390_root_dev_release;
 514         ret = device_register(dev);
 515         if (ret) {
 516                 kfree(dev);
 517                 return ERR_PTR(ret);
 518         }
 519         return dev;
 520 }
 521
 522 void
 523 s390_root_dev_unregister(struct device *dev)
 524 {
 525         if (dev)
 526                 device_unregister(dev);
 527 }
 528
 529 int
 530 css_enqueue_subchannel_slow(unsigned long schid)
 531 {
 532         struct slow_subchannel *new_slow_sch;
 533         unsigned long flags;
 534
 535         new_slow_sch = kmalloc(sizeof(struct slow_subchannel), GFP_ATOMIC);
 536         if (!new_slow_sch)
 537                 return -ENOMEM;
 538         memset(new_slow_sch, 0, sizeof(struct slow_subchannel));
 539         new_slow_sch->schid = schid;
 540         spin_lock_irqsave(&slow_subchannel_lock, flags);
 541         list_add_tail(&new_slow_sch->slow_list, &slow_subchannels_head);
 542         spin_unlock_irqrestore(&slow_subchannel_lock, flags);
 543         return 0;
 544 }
 545
 546 void
 547 css_clear_subchannel_slow_list(void)
 548 {
 549         unsigned long flags;
 550
 551         spin_lock_irqsave(&slow_subchannel_lock, flags);
 552         while (!list_empty(&slow_subchannels_head)) {
 553                 struct slow_subchannel *slow_sch =
 554                         list_entry(slow_subchannels_head.next,
 555                                    struct slow_subchannel, slow_list);
 556
 557                 list_del_init(slow_subchannels_head.next);
 558                 kfree(slow_sch);
 559         }
 560         spin_unlock_irqrestore(&slow_subchannel_lock, flags);
 561 }
 562
 563
 564
 565 int
 566 css_slow_subchannels_exist(void)
 567 {
 568         return (!list_empty(&slow_subchannels_head));
 569 }
 570
 571 MODULE_LICENSE("GPL");
 572 EXPORT_SYMBOL(css_bus_type);
 573 EXPORT_SYMBOL(s390_root_dev_register);
 574 EXPORT_SYMBOL(s390_root_dev_unregister);
 575 EXPORT_SYMBOL_GPL(css_characteristics_avail);