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   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 static int
 132 check_subchannel(struct device * dev, void * data)
 133 {
 134         struct subchannel *sch;
 135         int irq = (unsigned long)data;
 136
 137         sch = to_subchannel(dev);
 138         return (sch->irq == irq);
 139 }
 140
 141 struct subchannel *
 142 get_subchannel_by_schid(int irq)
 143 {
 144         struct device *dev;
 145
 146         dev = bus_find_device(&css_bus_type, NULL,
 147                               (void *)(unsigned long)irq, check_subchannel);
 148
 149         return dev ? to_subchannel(dev) : NULL;
 150 }
 151
 152
 153 static inline int
 154 css_get_subchannel_status(struct subchannel *sch, int schid)
 155 {
 156         struct schib schib;
 157         int cc;
 158
 159         cc = stsch(schid, &schib);
 160         if (cc)
 161                 return CIO_GONE;
 162         if (!schib.pmcw.dnv)
 163                 return CIO_GONE;
 164         if (sch && sch->schib.pmcw.dnv &&
 165             (schib.pmcw.dev != sch->schib.pmcw.dev))
 166                 return CIO_REVALIDATE;
 167         if (sch && !sch->lpm)
 168                 return CIO_NO_PATH;
 169         return CIO_OPER;
 170 }
 171
 172 static int
 173 css_evaluate_subchannel(int irq, int slow)
 174 {
 175         int event, ret, disc;
 176         struct subchannel *sch;
 177         unsigned long flags;
 178
 179         sch = get_subchannel_by_schid(irq);
 180         disc = sch ? device_is_disconnected(sch) : 0;
 181         if (disc && slow) {
 182                 if (sch)
 183                         put_device(&sch->dev);
 184                 return 0; /* Already processed. */
 185         }
 186         /*
 187          * We've got a machine check, so running I/O won't get an interrupt.
 188          * Kill any pending timers.
 189          */
 190         if (sch)
 191                 device_kill_pending_timer(sch);
 192         if (!disc && !slow) {
 193                 if (sch)
 194                         put_device(&sch->dev);
 195                 return -EAGAIN; /* Will be done on the slow path. */
 196         }
 197         event = css_get_subchannel_status(sch, irq);
 198         CIO_MSG_EVENT(4, "Evaluating schid %04x, event %d, %s, %s path.\n",
 199                       irq, event, sch?(disc?"disconnected":"normal"):"unknown",
 200                       slow?"slow":"fast");
 201         switch (event) {
 202         case CIO_NO_PATH:
 203         case CIO_GONE:
 204                 if (!sch) {
 205                         /* Never used this subchannel. Ignore. */
 206                         ret = 0;
 207                         break;
 208                 }
 209                 if (disc && (event == CIO_NO_PATH)) {
 210                         /*
 211                          * Uargh, hack again. Because we don't get a machine
 212                          * check on configure on, our path bookkeeping can
 213                          * be out of date here (it's fine while we only do
 214                          * logical varying or get chsc machine checks). We
 215                          * need to force reprobing or we might miss devices
 216                          * coming operational again. It won't do harm in real
 217                          * no path situations.
 218                          */
 219                         spin_lock_irqsave(&sch->lock, flags);
 220                         device_trigger_reprobe(sch);
 221                         spin_unlock_irqrestore(&sch->lock, flags);
 222                         ret = 0;
 223                         break;
 224                 }
 225                 if (sch->driver && sch->driver->notify &&
 226                     sch->driver->notify(&sch->dev, event)) {
 227                         cio_disable_subchannel(sch);
 228                         device_set_disconnected(sch);
 229                         ret = 0;
 230                         break;
 231                 }
 232                 /*
 233                  * Unregister subchannel.
 234                  * The device will be killed automatically.
 235                  */
 236                 cio_disable_subchannel(sch);
 237                 device_unregister(&sch->dev);
 238                 /* Reset intparm to zeroes. */
 239                 sch->schib.pmcw.intparm = 0;
 240                 cio_modify(sch);
 241                 put_device(&sch->dev);
 242                 ret = 0;
 243                 break;
 244         case CIO_REVALIDATE:
 245                 /*
 246                  * Revalidation machine check. Sick.
 247                  * We don't notify the driver since we have to throw the device
 248                  * away in any case.
 249                  */
 250                 if (!disc) {
 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 = css_probe_device(irq);
 257                 } else {
 258                         /*
 259                          * We can't immediately deregister the disconnected
 260                          * device since it might block.
 261                          */
 262                         spin_lock_irqsave(&sch->lock, flags);
 263                         device_trigger_reprobe(sch);
 264                         spin_unlock_irqrestore(&sch->lock, flags);
 265                         ret = 0;
 266                 }
 267                 break;
 268         case CIO_OPER:
 269                 if (disc) {
 270                         spin_lock_irqsave(&sch->lock, flags);
 271                         /* Get device operational again. */
 272                         device_trigger_reprobe(sch);
 273                         spin_unlock_irqrestore(&sch->lock, flags);
 274                 }
 275                 ret = sch ? 0 : css_probe_device(irq);
 276                 break;
 277         default:
 278                 BUG();
 279                 ret = 0;
 280         }
 281         return ret;
 282 }
 283
 284 static void
 285 css_rescan_devices(void)
 286 {
 287         int irq, ret;
 288
 289         for (irq = 0; irq < __MAX_SUBCHANNELS; irq++) {
 290                 ret = css_evaluate_subchannel(irq, 1);
 291                 /* No more memory. It doesn't make sense to continue. No
 292                  * panic because this can happen in midflight and just
 293                  * because we can't use a new device is no reason to crash
 294                  * the system. */
 295                 if (ret == -ENOMEM)
 296                         break;
 297                 /* -ENXIO indicates that there are no more subchannels. */
 298                 if (ret == -ENXIO)
 299                         break;
 300         }
 301 }
 302
 303 struct slow_subchannel {
 304         struct list_head slow_list;
 305         unsigned long schid;
 306 };
 307
 308 static LIST_HEAD(slow_subchannels_head);
 309 static DEFINE_SPINLOCK(slow_subchannel_lock);
 310
 311 static void
 312 css_trigger_slow_path(void)
 313 {
 314         CIO_TRACE_EVENT(4, "slowpath");
 315
 316         if (need_rescan) {
 317                 need_rescan = 0;
 318                 css_rescan_devices();
 319                 return;
 320         }
 321
 322         spin_lock_irq(&slow_subchannel_lock);
 323         while (!list_empty(&slow_subchannels_head)) {
 324                 struct slow_subchannel *slow_sch =
 325                         list_entry(slow_subchannels_head.next,
 326                                    struct slow_subchannel, slow_list);
 327
 328                 list_del_init(slow_subchannels_head.next);
 329                 spin_unlock_irq(&slow_subchannel_lock);
 330                 css_evaluate_subchannel(slow_sch->schid, 1);
 331                 spin_lock_irq(&slow_subchannel_lock);
 332                 kfree(slow_sch);
 333         }
 334         spin_unlock_irq(&slow_subchannel_lock);
 335 }
 336
 337 typedef void (*workfunc)(void *);
 338 DECLARE_WORK(slow_path_work, (workfunc)css_trigger_slow_path, NULL);
 339 struct workqueue_struct *slow_path_wq;
 340
 341 /*
 342  * Rescan for new devices. FIXME: This is slow.
 343  * This function is called when we have lost CRWs due to overflows and we have
 344  * to do subchannel housekeeping.
 345  */
 346 void
 347 css_reiterate_subchannels(void)
 348 {
 349         css_clear_subchannel_slow_list();
 350         need_rescan = 1;
 351 }
 352
 353 /*
 354  * Called from the machine check handler for subchannel report words.
 355  */
 356 int
 357 css_process_crw(int irq)
 358 {
 359         int ret;
 360
 361         CIO_CRW_EVENT(2, "source is subchannel %04X\n", irq);
 362
 363         if (need_rescan)
 364                 /* We need to iterate all subchannels anyway. */
 365                 return -EAGAIN;
 366         /*
 367          * Since we are always presented with IPI in the CRW, we have to
 368          * use stsch() to find out if the subchannel in question has come
 369          * or gone.
 370          */
 371         ret = css_evaluate_subchannel(irq, 0);
 372         if (ret == -EAGAIN) {
 373                 if (css_enqueue_subchannel_slow(irq)) {
 374                         css_clear_subchannel_slow_list();
 375                         need_rescan = 1;
 376                 }
 377         }
 378         return ret;
 379 }
 380
 381 static void __init
 382 css_generate_pgid(void)
 383 {
 384         /* Let's build our path group ID here. */
 385         if (css_characteristics_avail && css_general_characteristics.mcss)
 386                 global_pgid.cpu_addr = 0x8000;
 387         else {
 388 #ifdef CONFIG_SMP
 389                 global_pgid.cpu_addr = hard_smp_processor_id();
 390 #else
 391                 global_pgid.cpu_addr = 0;
 392 #endif
 393         }
 394         global_pgid.cpu_id = ((cpuid_t *) __LC_CPUID)->ident;
 395         global_pgid.cpu_model = ((cpuid_t *) __LC_CPUID)->machine;
 396         global_pgid.tod_high = (__u32) (get_clock() >> 32);
 397 }
 398
 399 /*
 400  * Now that the driver core is running, we can setup our channel subsystem.
 401  * The struct subchannel's are created during probing (except for the
 402  * static console subchannel).
 403  */
 404 static int __init
 405 init_channel_subsystem (void)
 406 {
 407         int ret, irq;
 408
 409         if (chsc_determine_css_characteristics() == 0)
 410                 css_characteristics_avail = 1;
 411
 412         css_generate_pgid();
 413
 414         if ((ret = bus_register(&css_bus_type)))
 415                 goto out;
 416         if ((ret = device_register (&css_bus_device)))
 417                 goto out_bus;
 418
 419         css_init_done = 1;
 420
 421         ctl_set_bit(6, 28);
 422
 423         for (irq = 0; irq < __MAX_SUBCHANNELS; irq++) {
 424                 struct subchannel *sch;
 425
 426                 if (cio_is_console(irq))
 427                         sch = cio_get_console_subchannel();
 428                 else {
 429                         sch = css_alloc_subchannel(irq);
 430                         if (IS_ERR(sch))
 431                                 ret = PTR_ERR(sch);
 432                         else
 433                                 ret = 0;
 434                         if (ret == -ENOMEM)
 435                                 panic("Out of memory in "
 436                                       "init_channel_subsystem\n");
 437                         /* -ENXIO: no more subchannels. */
 438                         if (ret == -ENXIO)
 439                                 break;
 440                         if (ret)
 441                                 continue;
 442                 }
 443                 /*
 444                  * We register ALL valid subchannels in ioinfo, even those
 445                  * that have been present before init_channel_subsystem.
 446                  * These subchannels can't have been registered yet (kmalloc
 447                  * not working) so we do it now. This is true e.g. for the
 448                  * console subchannel.
 449                  */
 450                 css_register_subchannel(sch);
 451         }
 452         return 0;
 453
 454 out_bus:
 455         bus_unregister(&css_bus_type);
 456 out:
 457         return ret;
 458 }
 459
 460 /*
 461  * find a driver for a subchannel. They identify by the subchannel
 462  * type with the exception that the console subchannel driver has its own
 463  * subchannel type although the device is an i/o subchannel
 464  */
 465 static int
 466 css_bus_match (struct device *dev, struct device_driver *drv)
 467 {
 468         struct subchannel *sch = container_of (dev, struct subchannel, dev);
 469         struct css_driver *driver = container_of (drv, struct css_driver, drv);
 470
 471         if (sch->st == driver->subchannel_type)
 472                 return 1;
 473
 474         return 0;
 475 }
 476
 477 struct bus_type css_bus_type = {
 478         .name  = "css",
 479         .match = &css_bus_match,
 480 };
 481
 482 subsys_initcall(init_channel_subsystem);
 483
 484 /*
 485  * Register root devices for some drivers. The release function must not be
 486  * in the device drivers, so we do it here.
 487  */
 488 static void
 489 s390_root_dev_release(struct device *dev)
 490 {
 491         kfree(dev);
 492 }
 493
 494 struct device *
 495 s390_root_dev_register(const char *name)
 496 {
 497         struct device *dev;
 498         int ret;
 499
 500         if (!strlen(name))
 501                 return ERR_PTR(-EINVAL);
 502         dev = kmalloc(sizeof(struct device), GFP_KERNEL);
 503         if (!dev)
 504                 return ERR_PTR(-ENOMEM);
 505         memset(dev, 0, sizeof(struct device));
 506         strncpy(dev->bus_id, name, min(strlen(name), (size_t)BUS_ID_SIZE));
 507         dev->release = s390_root_dev_release;
 508         ret = device_register(dev);
 509         if (ret) {
 510                 kfree(dev);
 511                 return ERR_PTR(ret);
 512         }
 513         return dev;
 514 }
 515
 516 void
 517 s390_root_dev_unregister(struct device *dev)
 518 {
 519         if (dev)
 520                 device_unregister(dev);
 521 }
 522
 523 int
 524 css_enqueue_subchannel_slow(unsigned long schid)
 525 {
 526         struct slow_subchannel *new_slow_sch;
 527         unsigned long flags;
 528
 529         new_slow_sch = kmalloc(sizeof(struct slow_subchannel), GFP_ATOMIC);
 530         if (!new_slow_sch)
 531                 return -ENOMEM;
 532         memset(new_slow_sch, 0, sizeof(struct slow_subchannel));
 533         new_slow_sch->schid = schid;
 534         spin_lock_irqsave(&slow_subchannel_lock, flags);
 535         list_add_tail(&new_slow_sch->slow_list, &slow_subchannels_head);
 536         spin_unlock_irqrestore(&slow_subchannel_lock, flags);
 537         return 0;
 538 }
 539
 540 void
 541 css_clear_subchannel_slow_list(void)
 542 {
 543         unsigned long flags;
 544
 545         spin_lock_irqsave(&slow_subchannel_lock, flags);
 546         while (!list_empty(&slow_subchannels_head)) {
 547                 struct slow_subchannel *slow_sch =
 548                         list_entry(slow_subchannels_head.next,
 549                                    struct slow_subchannel, slow_list);
 550
 551                 list_del_init(slow_subchannels_head.next);
 552                 kfree(slow_sch);
 553         }
 554         spin_unlock_irqrestore(&slow_subchannel_lock, flags);
 555 }
 556
 557
 558
 559 int
 560 css_slow_subchannels_exist(void)
 561 {
 562         return (!list_empty(&slow_subchannels_head));
 563 }
 564
 565 MODULE_LICENSE("GPL");
 566 EXPORT_SYMBOL(css_bus_type);
 567 EXPORT_SYMBOL(s390_root_dev_register);
 568 EXPORT_SYMBOL(s390_root_dev_unregister);
 569 EXPORT_SYMBOL_GPL(css_characteristics_avail);