git.oblomov.eu Git - linux-2.6/blob - 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 int need_rescan = 0;
  25 int css_init_done = 0;
  26
  27 struct pgid global_pgid;
  28 int css_characteristics_avail = 0;
  29
  30 struct device css_bus_device = {
  31         .bus_id = "css0",
  32 };
  33
  34 inline int
  35 for_each_subchannel(int(*fn)(struct subchannel_id, void *), void *data)
  36 {
  37         struct subchannel_id schid;
  38         int ret;
  39
  40         init_subchannel_id(&schid);
  41         ret = -ENODEV;
  42         do {
  43                 ret = fn(schid, data);
  44                 if (ret)
  45                         break;
  46         } while (schid.sch_no++ < __MAX_SUBCHANNEL);
  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_bus_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 %04x, event %d, %s, %s path.\n",
 212                       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 irq)
 359 {
 360         int ret;
 361         struct subchannel_id mchk_schid;
 362
 363         CIO_CRW_EVENT(2, "source is subchannel %04X\n", irq);
 364
 365         if (need_rescan)
 366                 /* We need to iterate all subchannels anyway. */
 367                 return -EAGAIN;
 368
 369         init_subchannel_id(&mchk_schid);
 370         mchk_schid.sch_no = irq;
 371         /*
 372          * Since we are always presented with IPI in the CRW, we have to
 373          * use stsch() to find out if the subchannel in question has come
 374          * or gone.
 375          */
 376         ret = css_evaluate_subchannel(mchk_schid, 0);
 377         if (ret == -EAGAIN) {
 378                 if (css_enqueue_subchannel_slow(mchk_schid)) {
 379                         css_clear_subchannel_slow_list();
 380                         need_rescan = 1;
 381                 }
 382         }
 383         return ret;
 384 }
 385
 386 static int __init
 387 __init_channel_subsystem(struct subchannel_id schid, void *data)
 388 {
 389         struct subchannel *sch;
 390         int ret;
 391
 392         if (cio_is_console(schid))
 393                 sch = cio_get_console_subchannel();
 394         else {
 395                 sch = css_alloc_subchannel(schid);
 396                 if (IS_ERR(sch))
 397                         ret = PTR_ERR(sch);
 398                 else
 399                         ret = 0;
 400                 switch (ret) {
 401                 case 0:
 402                         break;
 403                 case -ENOMEM:
 404                         panic("Out of memory in init_channel_subsystem\n");
 405                 /* -ENXIO: no more subchannels. */
 406                 case -ENXIO:
 407                         return ret;
 408                 default:
 409                         return 0;
 410                 }
 411         }
 412         /*
 413          * We register ALL valid subchannels in ioinfo, even those
 414          * that have been present before init_channel_subsystem.
 415          * These subchannels can't have been registered yet (kmalloc
 416          * not working) so we do it now. This is true e.g. for the
 417          * console subchannel.
 418          */
 419         css_register_subchannel(sch);
 420         return 0;
 421 }
 422
 423 static void __init
 424 css_generate_pgid(void)
 425 {
 426         /* Let's build our path group ID here. */
 427         if (css_characteristics_avail && css_general_characteristics.mcss)
 428                 global_pgid.cpu_addr = 0x8000;
 429         else {
 430 #ifdef CONFIG_SMP
 431                 global_pgid.cpu_addr = hard_smp_processor_id();
 432 #else
 433                 global_pgid.cpu_addr = 0;
 434 #endif
 435         }
 436         global_pgid.cpu_id = ((cpuid_t *) __LC_CPUID)->ident;
 437         global_pgid.cpu_model = ((cpuid_t *) __LC_CPUID)->machine;
 438         global_pgid.tod_high = (__u32) (get_clock() >> 32);
 439 }
 440
 441 /*
 442  * Now that the driver core is running, we can setup our channel subsystem.
 443  * The struct subchannel's are created during probing (except for the
 444  * static console subchannel).
 445  */
 446 static int __init
 447 init_channel_subsystem (void)
 448 {
 449         int ret;
 450
 451         if (chsc_determine_css_characteristics() == 0)
 452                 css_characteristics_avail = 1;
 453
 454         css_generate_pgid();
 455
 456         if ((ret = bus_register(&css_bus_type)))
 457                 goto out;
 458         if ((ret = device_register (&css_bus_device)))
 459                 goto out_bus;
 460
 461         css_init_done = 1;
 462
 463         ctl_set_bit(6, 28);
 464
 465         for_each_subchannel(__init_channel_subsystem, NULL);
 466         return 0;
 467 out_bus:
 468         bus_unregister(&css_bus_type);
 469 out:
 470         return ret;
 471 }
 472
 473 /*
 474  * find a driver for a subchannel. They identify by the subchannel
 475  * type with the exception that the console subchannel driver has its own
 476  * subchannel type although the device is an i/o subchannel
 477  */
 478 static int
 479 css_bus_match (struct device *dev, struct device_driver *drv)
 480 {
 481         struct subchannel *sch = container_of (dev, struct subchannel, dev);
 482         struct css_driver *driver = container_of (drv, struct css_driver, drv);
 483
 484         if (sch->st == driver->subchannel_type)
 485                 return 1;
 486
 487         return 0;
 488 }
 489
 490 struct bus_type css_bus_type = {
 491         .name  = "css",
 492         .match = &css_bus_match,
 493 };
 494
 495 subsys_initcall(init_channel_subsystem);
 496
 497 int
 498 css_enqueue_subchannel_slow(struct subchannel_id schid)
 499 {
 500         struct slow_subchannel *new_slow_sch;
 501         unsigned long flags;
 502
 503         new_slow_sch = kmalloc(sizeof(struct slow_subchannel), GFP_ATOMIC);
 504         if (!new_slow_sch)
 505                 return -ENOMEM;
 506         memset(new_slow_sch, 0, sizeof(struct slow_subchannel));
 507         new_slow_sch->schid = schid;
 508         spin_lock_irqsave(&slow_subchannel_lock, flags);
 509         list_add_tail(&new_slow_sch->slow_list, &slow_subchannels_head);
 510         spin_unlock_irqrestore(&slow_subchannel_lock, flags);
 511         return 0;
 512 }
 513
 514 void
 515 css_clear_subchannel_slow_list(void)
 516 {
 517         unsigned long flags;
 518
 519         spin_lock_irqsave(&slow_subchannel_lock, flags);
 520         while (!list_empty(&slow_subchannels_head)) {
 521                 struct slow_subchannel *slow_sch =
 522                         list_entry(slow_subchannels_head.next,
 523                                    struct slow_subchannel, slow_list);
 524
 525                 list_del_init(slow_subchannels_head.next);
 526                 kfree(slow_sch);
 527         }
 528         spin_unlock_irqrestore(&slow_subchannel_lock, flags);
 529 }
 530
 531
 532
 533 int
 534 css_slow_subchannels_exist(void)
 535 {
 536         return (!list_empty(&slow_subchannels_head));
 537 }
 538
 539 MODULE_LICENSE("GPL");
 540 EXPORT_SYMBOL(css_bus_type);
 541 EXPORT_SYMBOL_GPL(css_characteristics_avail);