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