drivers/s390/cio/cio.c

   1 /*
   2  *  drivers/s390/cio/cio.c
   3  *   S/390 common I/O routines -- low level i/o calls
   4  *   $Revision: 1.138 $
   5  *
   6  *    Copyright (C) 1999-2002 IBM Deutschland Entwicklung GmbH,
   7  *                            IBM Corporation
   8  *    Author(s): Ingo Adlung (adlung@de.ibm.com)
   9  *               Cornelia Huck (cohuck@de.ibm.com)
  10  *               Arnd Bergmann (arndb@de.ibm.com)
  11  *               Martin Schwidefsky (schwidefsky@de.ibm.com)
  12  */
  13
  14 #include <linux/module.h>
  15 #include <linux/config.h>
  16 #include <linux/init.h>
  17 #include <linux/slab.h>
  18 #include <linux/device.h>
  19 #include <linux/kernel_stat.h>
  20 #include <linux/interrupt.h>
  21
  22 #include <asm/cio.h>
  23 #include <asm/delay.h>
  24 #include <asm/irq.h>
  25
  26 #include "airq.h"
  27 #include "cio.h"
  28 #include "css.h"
  29 #include "chsc.h"
  30 #include "ioasm.h"
  31 #include "blacklist.h"
  32 #include "cio_debug.h"
  33
  34 debug_info_t *cio_debug_msg_id;
  35 debug_info_t *cio_debug_trace_id;
  36 debug_info_t *cio_debug_crw_id;
  37
  38 int cio_show_msg;
  39
  40 static int __init
  41 cio_setup (char *parm)
  42 {
  43         if (!strcmp (parm, "yes"))
  44                 cio_show_msg = 1;
  45         else if (!strcmp (parm, "no"))
  46                 cio_show_msg = 0;
  47         else
  48                 printk (KERN_ERR "cio_setup : invalid cio_msg parameter '%s'",
  49                         parm);
  50         return 1;
  51 }
  52
  53 __setup ("cio_msg=", cio_setup);
  54
  55 /*
  56  * Function: cio_debug_init
  57  * Initializes three debug logs (under /proc/s390dbf) for common I/O:
  58  * - cio_msg logs the messages which are printk'ed when CONFIG_DEBUG_IO is on
  59  * - cio_trace logs the calling of different functions
  60  * - cio_crw logs the messages which are printk'ed when CONFIG_DEBUG_CRW is on
  61  * debug levels depend on CONFIG_DEBUG_IO resp. CONFIG_DEBUG_CRW
  62  */
  63 static int __init
  64 cio_debug_init (void)
  65 {
  66         cio_debug_msg_id = debug_register ("cio_msg", 16, 4, 16*sizeof (long));
  67         if (!cio_debug_msg_id)
  68                 goto out_unregister;
  69         debug_register_view (cio_debug_msg_id, &debug_sprintf_view);
  70         debug_set_level (cio_debug_msg_id, 2);
  71         cio_debug_trace_id = debug_register ("cio_trace", 16, 4, 8);
  72         if (!cio_debug_trace_id)
  73                 goto out_unregister;
  74         debug_register_view (cio_debug_trace_id, &debug_hex_ascii_view);
  75         debug_set_level (cio_debug_trace_id, 2);
  76         cio_debug_crw_id = debug_register ("cio_crw", 4, 4, 16*sizeof (long));
  77         if (!cio_debug_crw_id)
  78                 goto out_unregister;
  79         debug_register_view (cio_debug_crw_id, &debug_sprintf_view);
  80         debug_set_level (cio_debug_crw_id, 2);
  81         pr_debug("debugging initialized\n");
  82         return 0;
  83
  84 out_unregister:
  85         if (cio_debug_msg_id)
  86                 debug_unregister (cio_debug_msg_id);
  87         if (cio_debug_trace_id)
  88                 debug_unregister (cio_debug_trace_id);
  89         if (cio_debug_crw_id)
  90                 debug_unregister (cio_debug_crw_id);
  91         pr_debug("could not initialize debugging\n");
  92         return -1;
  93 }
  94
  95 arch_initcall (cio_debug_init);
  96
  97 int
  98 cio_set_options (struct subchannel *sch, int flags)
  99 {
 100        sch->options.suspend = (flags & DOIO_ALLOW_SUSPEND) != 0;
 101        sch->options.prefetch = (flags & DOIO_DENY_PREFETCH) != 0;
 102        sch->options.inter = (flags & DOIO_SUPPRESS_INTER) != 0;
 103        return 0;
 104 }
 105
 106 /* FIXME: who wants to use this? */
 107 int
 108 cio_get_options (struct subchannel *sch)
 109 {
 110        int flags;
 111
 112        flags = 0;
 113        if (sch->options.suspend)
 114                 flags |= DOIO_ALLOW_SUSPEND;
 115        if (sch->options.prefetch)
 116                 flags |= DOIO_DENY_PREFETCH;
 117        if (sch->options.inter)
 118                 flags |= DOIO_SUPPRESS_INTER;
 119        return flags;
 120 }
 121
 122 /*
 123  * Use tpi to get a pending interrupt, call the interrupt handler and
 124  * return a pointer to the subchannel structure.
 125  */
 126 static inline int
 127 cio_tpi(void)
 128 {
 129         struct tpi_info *tpi_info;
 130         struct subchannel *sch;
 131         struct irb *irb;
 132
 133         tpi_info = (struct tpi_info *) __LC_SUBCHANNEL_ID;
 134         if (tpi (NULL) != 1)
 135                 return 0;
 136         irb = (struct irb *) __LC_IRB;
 137         /* Store interrupt response block to lowcore. */
 138         if (tsch (tpi_info->schid, irb) != 0)
 139                 /* Not status pending or not operational. */
 140                 return 1;
 141         sch = (struct subchannel *)(unsigned long)tpi_info->intparm;
 142         if (!sch)
 143                 return 1;
 144         local_bh_disable();
 145         irq_enter ();
 146         spin_lock(&sch->lock);
 147         memcpy (&sch->schib.scsw, &irb->scsw, sizeof (struct scsw));
 148         if (sch->driver && sch->driver->irq)
 149                 sch->driver->irq(&sch->dev);
 150         spin_unlock(&sch->lock);
 151         irq_exit ();
 152         __local_bh_enable();
 153         return 1;
 154 }
 155
 156 static inline int
 157 cio_start_handle_notoper(struct subchannel *sch, __u8 lpm)
 158 {
 159         char dbf_text[15];
 160
 161         if (lpm != 0)
 162                 sch->lpm &= ~lpm;
 163         else
 164                 sch->lpm = 0;
 165
 166         stsch (sch->schid, &sch->schib);
 167
 168         CIO_MSG_EVENT(0, "cio_start: 'not oper' status for "
 169                       "subchannel 0.%x.%04x!\n", sch->schid.ssid,
 170                       sch->schid.sch_no);
 171         sprintf(dbf_text, "no%s", sch->dev.bus_id);
 172         CIO_TRACE_EVENT(0, dbf_text);
 173         CIO_HEX_EVENT(0, &sch->schib, sizeof (struct schib));
 174
 175         return (sch->lpm ? -EACCES : -ENODEV);
 176 }
 177
 178 int
 179 cio_start_key (struct subchannel *sch,  /* subchannel structure */
 180                struct ccw1 * cpa,       /* logical channel prog addr */
 181                __u8 lpm,                /* logical path mask */
 182                __u8 key)                /* storage key */
 183 {
 184         char dbf_txt[15];
 185         int ccode;
 186
 187         CIO_TRACE_EVENT (4, "stIO");
 188         CIO_TRACE_EVENT (4, sch->dev.bus_id);
 189
 190         /* sch is always under 2G. */
 191         sch->orb.intparm = (__u32)(unsigned long)sch;
 192         sch->orb.fmt = 1;
 193
 194         sch->orb.pfch = sch->options.prefetch == 0;
 195         sch->orb.spnd = sch->options.suspend;
 196         sch->orb.ssic = sch->options.suspend && sch->options.inter;
 197         sch->orb.lpm = (lpm != 0) ? (lpm & sch->opm) : sch->lpm;
 198 #ifdef CONFIG_64BIT
 199         /*
 200          * for 64 bit we always support 64 bit IDAWs with 4k page size only
 201          */
 202         sch->orb.c64 = 1;
 203         sch->orb.i2k = 0;
 204 #endif
 205         sch->orb.key = key >> 4;
 206         /* issue "Start Subchannel" */
 207         sch->orb.cpa = (__u32) __pa (cpa);
 208         ccode = ssch (sch->schid, &sch->orb);
 209
 210         /* process condition code */
 211         sprintf (dbf_txt, "ccode:%d", ccode);
 212         CIO_TRACE_EVENT (4, dbf_txt);
 213
 214         switch (ccode) {
 215         case 0:
 216                 /*
 217                  * initialize device status information
 218                  */
 219                 sch->schib.scsw.actl |= SCSW_ACTL_START_PEND;
 220                 return 0;
 221         case 1:         /* status pending */
 222         case 2:         /* busy */
 223                 return -EBUSY;
 224         default:                /* device/path not operational */
 225                 return cio_start_handle_notoper(sch, lpm);
 226         }
 227 }
 228
 229 int
 230 cio_start (struct subchannel *sch, struct ccw1 *cpa, __u8 lpm)
 231 {
 232         return cio_start_key(sch, cpa, lpm, PAGE_DEFAULT_KEY);
 233 }
 234
 235 /*
 236  * resume suspended I/O operation
 237  */
 238 int
 239 cio_resume (struct subchannel *sch)
 240 {
 241         char dbf_txt[15];
 242         int ccode;
 243
 244         CIO_TRACE_EVENT (4, "resIO");
 245         CIO_TRACE_EVENT (4, sch->dev.bus_id);
 246
 247         ccode = rsch (sch->schid);
 248
 249         sprintf (dbf_txt, "ccode:%d", ccode);
 250         CIO_TRACE_EVENT (4, dbf_txt);
 251
 252         switch (ccode) {
 253         case 0:
 254                 sch->schib.scsw.actl |= SCSW_ACTL_RESUME_PEND;
 255                 return 0;
 256         case 1:
 257                 return -EBUSY;
 258         case 2:
 259                 return -EINVAL;
 260         default:
 261                 /*
 262                  * useless to wait for request completion
 263                  *  as device is no longer operational !
 264                  */
 265                 return -ENODEV;
 266         }
 267 }
 268
 269 /*
 270  * halt I/O operation
 271  */
 272 int
 273 cio_halt(struct subchannel *sch)
 274 {
 275         char dbf_txt[15];
 276         int ccode;
 277
 278         if (!sch)
 279                 return -ENODEV;
 280
 281         CIO_TRACE_EVENT (2, "haltIO");
 282         CIO_TRACE_EVENT (2, sch->dev.bus_id);
 283
 284         /*
 285          * Issue "Halt subchannel" and process condition code
 286          */
 287         ccode = hsch (sch->schid);
 288
 289         sprintf (dbf_txt, "ccode:%d", ccode);
 290         CIO_TRACE_EVENT (2, dbf_txt);
 291
 292         switch (ccode) {
 293         case 0:
 294                 sch->schib.scsw.actl |= SCSW_ACTL_HALT_PEND;
 295                 return 0;
 296         case 1:         /* status pending */
 297         case 2:         /* busy */
 298                 return -EBUSY;
 299         default:                /* device not operational */
 300                 return -ENODEV;
 301         }
 302 }
 303
 304 /*
 305  * Clear I/O operation
 306  */
 307 int
 308 cio_clear(struct subchannel *sch)
 309 {
 310         char dbf_txt[15];
 311         int ccode;
 312
 313         if (!sch)
 314                 return -ENODEV;
 315
 316         CIO_TRACE_EVENT (2, "clearIO");
 317         CIO_TRACE_EVENT (2, sch->dev.bus_id);
 318
 319         /*
 320          * Issue "Clear subchannel" and process condition code
 321          */
 322         ccode = csch (sch->schid);
 323
 324         sprintf (dbf_txt, "ccode:%d", ccode);
 325         CIO_TRACE_EVENT (2, dbf_txt);
 326
 327         switch (ccode) {
 328         case 0:
 329                 sch->schib.scsw.actl |= SCSW_ACTL_CLEAR_PEND;
 330                 return 0;
 331         default:                /* device not operational */
 332                 return -ENODEV;
 333         }
 334 }
 335
 336 /*
 337  * Function: cio_cancel
 338  * Issues a "Cancel Subchannel" on the specified subchannel
 339  * Note: We don't need any fancy intparms and flags here
 340  *       since xsch is executed synchronously.
 341  * Only for common I/O internal use as for now.
 342  */
 343 int
 344 cio_cancel (struct subchannel *sch)
 345 {
 346         char dbf_txt[15];
 347         int ccode;
 348
 349         if (!sch)
 350                 return -ENODEV;
 351
 352         CIO_TRACE_EVENT (2, "cancelIO");
 353         CIO_TRACE_EVENT (2, sch->dev.bus_id);
 354
 355         ccode = xsch (sch->schid);
 356
 357         sprintf (dbf_txt, "ccode:%d", ccode);
 358         CIO_TRACE_EVENT (2, dbf_txt);
 359
 360         switch (ccode) {
 361         case 0:         /* success */
 362                 /* Update information in scsw. */
 363                 stsch (sch->schid, &sch->schib);
 364                 return 0;
 365         case 1:         /* status pending */
 366                 return -EBUSY;
 367         case 2:         /* not applicable */
 368                 return -EINVAL;
 369         default:        /* not oper */
 370                 return -ENODEV;
 371         }
 372 }
 373
 374 /*
 375  * Function: cio_modify
 376  * Issues a "Modify Subchannel" on the specified subchannel
 377  */
 378 int
 379 cio_modify (struct subchannel *sch)
 380 {
 381         int ccode, retry, ret;
 382
 383         ret = 0;
 384         for (retry = 0; retry < 5; retry++) {
 385                 ccode = msch_err (sch->schid, &sch->schib);
 386                 if (ccode < 0)  /* -EIO if msch gets a program check. */
 387                         return ccode;
 388                 switch (ccode) {
 389                 case 0: /* successfull */
 390                         return 0;
 391                 case 1: /* status pending */
 392                         return -EBUSY;
 393                 case 2: /* busy */
 394                         udelay (100);   /* allow for recovery */
 395                         ret = -EBUSY;
 396                         break;
 397                 case 3: /* not operational */
 398                         return -ENODEV;
 399                 }
 400         }
 401         return ret;
 402 }
 403
 404 /*
 405  * Enable subchannel.
 406  */
 407 int
 408 cio_enable_subchannel (struct subchannel *sch, unsigned int isc)
 409 {
 410         char dbf_txt[15];
 411         int ccode;
 412         int retry;
 413         int ret;
 414
 415         CIO_TRACE_EVENT (2, "ensch");
 416         CIO_TRACE_EVENT (2, sch->dev.bus_id);
 417
 418         ccode = stsch (sch->schid, &sch->schib);
 419         if (ccode)
 420                 return -ENODEV;
 421
 422         for (retry = 5, ret = 0; retry > 0; retry--) {
 423                 sch->schib.pmcw.ena = 1;
 424                 sch->schib.pmcw.isc = isc;
 425                 sch->schib.pmcw.intparm = (__u32)(unsigned long)sch;
 426                 ret = cio_modify(sch);
 427                 if (ret == -ENODEV)
 428                         break;
 429                 if (ret == -EIO)
 430                         /*
 431                          * Got a program check in cio_modify. Try without
 432                          * the concurrent sense bit the next time.
 433                          */
 434                         sch->schib.pmcw.csense = 0;
 435                 if (ret == 0) {
 436                         stsch (sch->schid, &sch->schib);
 437                         if (sch->schib.pmcw.ena)
 438                                 break;
 439                 }
 440                 if (ret == -EBUSY) {
 441                         struct irb irb;
 442                         if (tsch(sch->schid, &irb) != 0)
 443                                 break;
 444                 }
 445         }
 446         sprintf (dbf_txt, "ret:%d", ret);
 447         CIO_TRACE_EVENT (2, dbf_txt);
 448         return ret;
 449 }
 450
 451 /*
 452  * Disable subchannel.
 453  */
 454 int
 455 cio_disable_subchannel (struct subchannel *sch)
 456 {
 457         char dbf_txt[15];
 458         int ccode;
 459         int retry;
 460         int ret;
 461
 462         CIO_TRACE_EVENT (2, "dissch");
 463         CIO_TRACE_EVENT (2, sch->dev.bus_id);
 464
 465         ccode = stsch (sch->schid, &sch->schib);
 466         if (ccode == 3)         /* Not operational. */
 467                 return -ENODEV;
 468
 469         if (sch->schib.scsw.actl != 0)
 470                 /*
 471                  * the disable function must not be called while there are
 472                  *  requests pending for completion !
 473                  */
 474                 return -EBUSY;
 475
 476         for (retry = 5, ret = 0; retry > 0; retry--) {
 477                 sch->schib.pmcw.ena = 0;
 478                 ret = cio_modify(sch);
 479                 if (ret == -ENODEV)
 480                         break;
 481                 if (ret == -EBUSY)
 482                         /*
 483                          * The subchannel is busy or status pending.
 484                          * We'll disable when the next interrupt was delivered
 485                          * via the state machine.
 486                          */
 487                         break;
 488                 if (ret == 0) {
 489                         stsch (sch->schid, &sch->schib);
 490                         if (!sch->schib.pmcw.ena)
 491                                 break;
 492                 }
 493         }
 494         sprintf (dbf_txt, "ret:%d", ret);
 495         CIO_TRACE_EVENT (2, dbf_txt);
 496         return ret;
 497 }
 498
 499 /*
 500  * cio_validate_subchannel()
 501  *
 502  * Find out subchannel type and initialize struct subchannel.
 503  * Return codes:
 504  *   SUBCHANNEL_TYPE_IO for a normal io subchannel
 505  *   SUBCHANNEL_TYPE_CHSC for a chsc subchannel
 506  *   SUBCHANNEL_TYPE_MESSAGE for a messaging subchannel
 507  *   SUBCHANNEL_TYPE_ADM for a adm(?) subchannel
 508  *   -ENXIO for non-defined subchannels
 509  *   -ENODEV for subchannels with invalid device number or blacklisted devices
 510  */
 511 int
 512 cio_validate_subchannel (struct subchannel *sch, struct subchannel_id schid)
 513 {
 514         char dbf_txt[15];
 515         int ccode;
 516
 517         sprintf (dbf_txt, "valsch%x", schid.sch_no);
 518         CIO_TRACE_EVENT (4, dbf_txt);
 519
 520         /* Nuke all fields. */
 521         memset(sch, 0, sizeof(struct subchannel));
 522
 523         spin_lock_init(&sch->lock);
 524
 525         /* Set a name for the subchannel */
 526         snprintf (sch->dev.bus_id, BUS_ID_SIZE, "0.%x.%04x", schid.ssid,
 527                   schid.sch_no);
 528
 529         /*
 530          * The first subchannel that is not-operational (ccode==3)
 531          *  indicates that there aren't any more devices available.
 532          * If stsch gets an exception, it means the current subchannel set
 533          *  is not valid.
 534          */
 535         ccode = stsch_err (schid, &sch->schib);
 536         if (ccode)
 537                 return (ccode == 3) ? -ENXIO : ccode;
 538
 539         sch->schid = schid;
 540         /* Copy subchannel type from path management control word. */
 541         sch->st = sch->schib.pmcw.st;
 542
 543         /*
 544          * ... just being curious we check for non I/O subchannels
 545          */
 546         if (sch->st != 0) {
 547                 CIO_DEBUG(KERN_INFO, 0,
 548                           "Subchannel 0.%x.%04x reports "
 549                           "non-I/O subchannel type %04X\n",
 550                           sch->schid.ssid, sch->schid.sch_no, sch->st);
 551                 /* We stop here for non-io subchannels. */
 552                 return sch->st;
 553         }
 554
 555         /* Initialization for io subchannels. */
 556         if (!sch->schib.pmcw.dnv)
 557                 /* io subchannel but device number is invalid. */
 558                 return -ENODEV;
 559
 560         /* Devno is valid. */
 561         if (is_blacklisted (sch->schid.ssid, sch->schib.pmcw.dev)) {
 562                 /*
 563                  * This device must not be known to Linux. So we simply
 564                  * say that there is no device and return ENODEV.
 565                  */
 566                 CIO_MSG_EVENT(0, "Blacklisted device detected "
 567                               "at devno %04X, subchannel set %x\n",
 568                               sch->schib.pmcw.dev, sch->schid.ssid);
 569                 return -ENODEV;
 570         }
 571         sch->opm = 0xff;
 572         if (!cio_is_console(sch->schid))
 573                 chsc_validate_chpids(sch);
 574         sch->lpm = sch->schib.pmcw.pim &
 575                 sch->schib.pmcw.pam &
 576                 sch->schib.pmcw.pom &
 577                 sch->opm;
 578
 579         CIO_DEBUG(KERN_INFO, 0,
 580                   "Detected device %04x on subchannel 0.%x.%04X"
 581                   " - PIM = %02X, PAM = %02X, POM = %02X\n",
 582                   sch->schib.pmcw.dev, sch->schid.ssid,
 583                   sch->schid.sch_no, sch->schib.pmcw.pim,
 584                   sch->schib.pmcw.pam, sch->schib.pmcw.pom);
 585
 586         /*
 587          * We now have to initially ...
 588          *  ... set "interruption subclass"
 589          *  ... enable "concurrent sense"
 590          *  ... enable "multipath mode" if more than one
 591          *        CHPID is available. This is done regardless
 592          *        whether multiple paths are available for us.
 593          */
 594         sch->schib.pmcw.isc = 3;        /* could be smth. else */
 595         sch->schib.pmcw.csense = 1;     /* concurrent sense */
 596         sch->schib.pmcw.ena = 0;
 597         if ((sch->lpm & (sch->lpm - 1)) != 0)
 598                 sch->schib.pmcw.mp = 1; /* multipath mode */
 599         return 0;
 600 }
 601
 602 /*
 603  * do_IRQ() handles all normal I/O device IRQ's (the special
 604  *          SMP cross-CPU interrupts have their own specific
 605  *          handlers).
 606  *
 607  */
 608 void
 609 do_IRQ (struct pt_regs *regs)
 610 {
 611         struct tpi_info *tpi_info;
 612         struct subchannel *sch;
 613         struct irb *irb;
 614
 615         irq_enter ();
 616         asm volatile ("mc 0,0");
 617         if (S390_lowcore.int_clock >= S390_lowcore.jiffy_timer)
 618                 /**
 619                  * Make sure that the i/o interrupt did not "overtake"
 620                  * the last HZ timer interrupt.
 621                  */
 622                 account_ticks(regs);
 623         /*
 624          * Get interrupt information from lowcore
 625          */
 626         tpi_info = (struct tpi_info *) __LC_SUBCHANNEL_ID;
 627         irb = (struct irb *) __LC_IRB;
 628         do {
 629                 kstat_cpu(smp_processor_id()).irqs[IO_INTERRUPT]++;
 630                 /*
 631                  * Non I/O-subchannel thin interrupts are processed differently
 632                  */
 633                 if (tpi_info->adapter_IO == 1 &&
 634                     tpi_info->int_type == IO_INTERRUPT_TYPE) {
 635                         do_adapter_IO();
 636                         continue;
 637                 }
 638                 sch = (struct subchannel *)(unsigned long)tpi_info->intparm;
 639                 if (sch)
 640                         spin_lock(&sch->lock);
 641                 /* Store interrupt response block to lowcore. */
 642                 if (tsch (tpi_info->schid, irb) == 0 && sch) {
 643                         /* Keep subchannel information word up to date. */
 644                         memcpy (&sch->schib.scsw, &irb->scsw,
 645                                 sizeof (irb->scsw));
 646                         /* Call interrupt handler if there is one. */
 647                         if (sch->driver && sch->driver->irq)
 648                                 sch->driver->irq(&sch->dev);
 649                 }
 650                 if (sch)
 651                         spin_unlock(&sch->lock);
 652                 /*
 653                  * Are more interrupts pending?
 654                  * If so, the tpi instruction will update the lowcore
 655                  * to hold the info for the next interrupt.
 656                  * We don't do this for VM because a tpi drops the cpu
 657                  * out of the sie which costs more cycles than it saves.
 658                  */
 659         } while (!MACHINE_IS_VM && tpi (NULL) != 0);
 660         irq_exit ();
 661 }
 662
 663 #ifdef CONFIG_CCW_CONSOLE
 664 static struct subchannel console_subchannel;
 665 static int console_subchannel_in_use;
 666
 667 /*
 668  * busy wait for the next interrupt on the console
 669  */
 670 void
 671 wait_cons_dev (void)
 672 {
 673         unsigned long cr6      __attribute__ ((aligned (8)));
 674         unsigned long save_cr6 __attribute__ ((aligned (8)));
 675
 676         /*
 677          * before entering the spinlock we may already have
 678          * processed the interrupt on a different CPU...
 679          */
 680         if (!console_subchannel_in_use)
 681                 return;
 682
 683         /* disable all but isc 7 (console device) */
 684         __ctl_store (save_cr6, 6, 6);
 685         cr6 = 0x01000000;
 686         __ctl_load (cr6, 6, 6);
 687
 688         do {
 689                 spin_unlock(&console_subchannel.lock);
 690                 if (!cio_tpi())
 691                         cpu_relax();
 692                 spin_lock(&console_subchannel.lock);
 693         } while (console_subchannel.schib.scsw.actl != 0);
 694         /*
 695          * restore previous isc value
 696          */
 697         __ctl_load (save_cr6, 6, 6);
 698 }
 699
 700 static int
 701 cio_test_for_console(struct subchannel_id schid, void *data)
 702 {
 703         if (stsch_err(schid, &console_subchannel.schib) != 0)
 704                 return -ENXIO;
 705         if (console_subchannel.schib.pmcw.dnv &&
 706             console_subchannel.schib.pmcw.dev ==
 707             console_devno) {
 708                 console_irq = schid.sch_no;
 709                 return 1; /* found */
 710         }
 711         return 0;
 712 }
 713
 714
 715 static int
 716 cio_get_console_sch_no(void)
 717 {
 718         struct subchannel_id schid;
 719
 720         init_subchannel_id(&schid);
 721         if (console_irq != -1) {
 722                 /* VM provided us with the irq number of the console. */
 723                 schid.sch_no = console_irq;
 724                 if (stsch(schid, &console_subchannel.schib) != 0 ||
 725                     !console_subchannel.schib.pmcw.dnv)
 726                         return -1;
 727                 console_devno = console_subchannel.schib.pmcw.dev;
 728         } else if (console_devno != -1) {
 729                 /* At least the console device number is known. */
 730                 for_each_subchannel(cio_test_for_console, NULL);
 731                 if (console_irq == -1)
 732                         return -1;
 733         } else {
 734                 /* unlike in 2.4, we cannot autoprobe here, since
 735                  * the channel subsystem is not fully initialized.
 736                  * With some luck, the HWC console can take over */
 737                 printk(KERN_WARNING "No ccw console found!\n");
 738                 return -1;
 739         }
 740         return console_irq;
 741 }
 742
 743 struct subchannel *
 744 cio_probe_console(void)
 745 {
 746         int sch_no, ret;
 747         struct subchannel_id schid;
 748
 749         if (xchg(&console_subchannel_in_use, 1) != 0)
 750                 return ERR_PTR(-EBUSY);
 751         sch_no = cio_get_console_sch_no();
 752         if (sch_no == -1) {
 753                 console_subchannel_in_use = 0;
 754                 return ERR_PTR(-ENODEV);
 755         }
 756         memset(&console_subchannel, 0, sizeof(struct subchannel));
 757         init_subchannel_id(&schid);
 758         schid.sch_no = sch_no;
 759         ret = cio_validate_subchannel(&console_subchannel, schid);
 760         if (ret) {
 761                 console_subchannel_in_use = 0;
 762                 return ERR_PTR(-ENODEV);
 763         }
 764
 765         /*
 766          * enable console I/O-interrupt subclass 7
 767          */
 768         ctl_set_bit(6, 24);
 769         console_subchannel.schib.pmcw.isc = 7;
 770         console_subchannel.schib.pmcw.intparm =
 771                 (__u32)(unsigned long)&console_subchannel;
 772         ret = cio_modify(&console_subchannel);
 773         if (ret) {
 774                 console_subchannel_in_use = 0;
 775                 return ERR_PTR(ret);
 776         }
 777         return &console_subchannel;
 778 }
 779
 780 void
 781 cio_release_console(void)
 782 {
 783         console_subchannel.schib.pmcw.intparm = 0;
 784         cio_modify(&console_subchannel);
 785         ctl_clear_bit(6, 24);
 786         console_subchannel_in_use = 0;
 787 }
 788
 789 /* Bah... hack to catch console special sausages. */
 790 int
 791 cio_is_console(struct subchannel_id schid)
 792 {
 793         if (!console_subchannel_in_use)
 794                 return 0;
 795         return schid_equal(&schid, &console_subchannel.schid);
 796 }
 797
 798 struct subchannel *
 799 cio_get_console_subchannel(void)
 800 {
 801         if (!console_subchannel_in_use)
 802                 return 0;
 803         return &console_subchannel;
 804 }
 805
 806 #endif
 807 static inline int
 808 __disable_subchannel_easy(struct subchannel_id schid, struct schib *schib)
 809 {
 810         int retry, cc;
 811
 812         cc = 0;
 813         for (retry=0;retry<3;retry++) {
 814                 schib->pmcw.ena = 0;
 815                 cc = msch(schid, schib);
 816                 if (cc)
 817                         return (cc==3?-ENODEV:-EBUSY);
 818                 stsch(schid, schib);
 819                 if (!schib->pmcw.ena)
 820                         return 0;
 821         }
 822         return -EBUSY; /* uhm... */
 823 }
 824
 825 static inline int
 826 __clear_subchannel_easy(struct subchannel_id schid)
 827 {
 828         int retry;
 829
 830         if (csch(schid))
 831                 return -ENODEV;
 832         for (retry=0;retry<20;retry++) {
 833                 struct tpi_info ti;
 834
 835                 if (tpi(&ti)) {
 836                         tsch(ti.schid, (struct irb *)__LC_IRB);
 837                         if (schid_equal(&ti.schid, &schid))
 838                                 return 0;
 839                 }
 840                 udelay(100);
 841         }
 842         return -EBUSY;
 843 }
 844
 845 extern void do_reipl(unsigned long devno);
 846 static int
 847 __shutdown_subchannel_easy(struct subchannel_id schid, void *data)
 848 {
 849         struct schib schib;
 850
 851         if (stsch_err(schid, &schib))
 852                 return -ENXIO;
 853         if (!schib.pmcw.ena)
 854                 return 0;
 855         switch(__disable_subchannel_easy(schid, &schib)) {
 856         case 0:
 857         case -ENODEV:
 858                 break;
 859         default: /* -EBUSY */
 860                 if (__clear_subchannel_easy(schid))
 861                         break; /* give up... */
 862                 stsch(schid, &schib);
 863                 __disable_subchannel_easy(schid, &schib);
 864         }
 865         return 0;
 866 }
 867
 868 void
 869 clear_all_subchannels(void)
 870 {
 871         local_irq_disable();
 872         for_each_subchannel(__shutdown_subchannel_easy, NULL);
 873 }
 874
 875 /* Make sure all subchannels are quiet before we re-ipl an lpar. */
 876 void
 877 reipl(unsigned long devno)
 878 {
 879         clear_all_subchannels();
 880         do_reipl(devno);
 881 }