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: 1.134 $
   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->irq, 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->irq, &sch->schib);
 167
 168         CIO_MSG_EVENT(0, "cio_start: 'not oper' status for "
 169                       "subchannel %04x!\n", sch->irq);
 170         sprintf(dbf_text, "no%s", sch->dev.bus_id);
 171         CIO_TRACE_EVENT(0, dbf_text);
 172         CIO_HEX_EVENT(0, &sch->schib, sizeof (struct schib));
 173
 174         return (sch->lpm ? -EACCES : -ENODEV);
 175 }
 176
 177 int
 178 cio_start_key (struct subchannel *sch,  /* subchannel structure */
 179                struct ccw1 * cpa,       /* logical channel prog addr */
 180                __u8 lpm,                /* logical path mask */
 181                __u8 key)                /* storage key */
 182 {
 183         char dbf_txt[15];
 184         int ccode;
 185
 186         CIO_TRACE_EVENT (4, "stIO");
 187         CIO_TRACE_EVENT (4, sch->dev.bus_id);
 188
 189         /* sch is always under 2G. */
 190         sch->orb.intparm = (__u32)(unsigned long)sch;
 191         sch->orb.fmt = 1;
 192
 193         sch->orb.pfch = sch->options.prefetch == 0;
 194         sch->orb.spnd = sch->options.suspend;
 195         sch->orb.ssic = sch->options.suspend && sch->options.inter;
 196         sch->orb.lpm = (lpm != 0) ? (lpm & sch->opm) : sch->lpm;
 197 #ifdef CONFIG_ARCH_S390X
 198         /*
 199          * for 64 bit we always support 64 bit IDAWs with 4k page size only
 200          */
 201         sch->orb.c64 = 1;
 202         sch->orb.i2k = 0;
 203 #endif
 204         sch->orb.key = key >> 4;
 205         /* issue "Start Subchannel" */
 206         sch->orb.cpa = (__u32) __pa (cpa);
 207         ccode = ssch (sch->irq, &sch->orb);
 208
 209         /* process condition code */
 210         sprintf (dbf_txt, "ccode:%d", ccode);
 211         CIO_TRACE_EVENT (4, dbf_txt);
 212
 213         switch (ccode) {
 214         case 0:
 215                 /*
 216                  * initialize device status information
 217                  */
 218                 sch->schib.scsw.actl |= SCSW_ACTL_START_PEND;
 219                 return 0;
 220         case 1:         /* status pending */
 221         case 2:         /* busy */
 222                 return -EBUSY;
 223         default:                /* device/path not operational */
 224                 return cio_start_handle_notoper(sch, lpm);
 225         }
 226 }
 227
 228 int
 229 cio_start (struct subchannel *sch, struct ccw1 *cpa, __u8 lpm)
 230 {
 231         return cio_start_key(sch, cpa, lpm, PAGE_DEFAULT_KEY);
 232 }
 233
 234 /*
 235  * resume suspended I/O operation
 236  */
 237 int
 238 cio_resume (struct subchannel *sch)
 239 {
 240         char dbf_txt[15];
 241         int ccode;
 242
 243         CIO_TRACE_EVENT (4, "resIO");
 244         CIO_TRACE_EVENT (4, sch->dev.bus_id);
 245
 246         ccode = rsch (sch->irq);
 247
 248         sprintf (dbf_txt, "ccode:%d", ccode);
 249         CIO_TRACE_EVENT (4, dbf_txt);
 250
 251         switch (ccode) {
 252         case 0:
 253                 sch->schib.scsw.actl |= SCSW_ACTL_RESUME_PEND;
 254                 return 0;
 255         case 1:
 256                 return -EBUSY;
 257         case 2:
 258                 return -EINVAL;
 259         default:
 260                 /*
 261                  * useless to wait for request completion
 262                  *  as device is no longer operational !
 263                  */
 264                 return -ENODEV;
 265         }
 266 }
 267
 268 /*
 269  * halt I/O operation
 270  */
 271 int
 272 cio_halt(struct subchannel *sch)
 273 {
 274         char dbf_txt[15];
 275         int ccode;
 276
 277         if (!sch)
 278                 return -ENODEV;
 279
 280         CIO_TRACE_EVENT (2, "haltIO");
 281         CIO_TRACE_EVENT (2, sch->dev.bus_id);
 282
 283         /*
 284          * Issue "Halt subchannel" and process condition code
 285          */
 286         ccode = hsch (sch->irq);
 287
 288         sprintf (dbf_txt, "ccode:%d", ccode);
 289         CIO_TRACE_EVENT (2, dbf_txt);
 290
 291         switch (ccode) {
 292         case 0:
 293                 sch->schib.scsw.actl |= SCSW_ACTL_HALT_PEND;
 294                 return 0;
 295         case 1:         /* status pending */
 296         case 2:         /* busy */
 297                 return -EBUSY;
 298         default:                /* device not operational */
 299                 return -ENODEV;
 300         }
 301 }
 302
 303 /*
 304  * Clear I/O operation
 305  */
 306 int
 307 cio_clear(struct subchannel *sch)
 308 {
 309         char dbf_txt[15];
 310         int ccode;
 311
 312         if (!sch)
 313                 return -ENODEV;
 314
 315         CIO_TRACE_EVENT (2, "clearIO");
 316         CIO_TRACE_EVENT (2, sch->dev.bus_id);
 317
 318         /*
 319          * Issue "Clear subchannel" and process condition code
 320          */
 321         ccode = csch (sch->irq);
 322
 323         sprintf (dbf_txt, "ccode:%d", ccode);
 324         CIO_TRACE_EVENT (2, dbf_txt);
 325
 326         switch (ccode) {
 327         case 0:
 328                 sch->schib.scsw.actl |= SCSW_ACTL_CLEAR_PEND;
 329                 return 0;
 330         default:                /* device not operational */
 331                 return -ENODEV;
 332         }
 333 }
 334
 335 /*
 336  * Function: cio_cancel
 337  * Issues a "Cancel Subchannel" on the specified subchannel
 338  * Note: We don't need any fancy intparms and flags here
 339  *       since xsch is executed synchronously.
 340  * Only for common I/O internal use as for now.
 341  */
 342 int
 343 cio_cancel (struct subchannel *sch)
 344 {
 345         char dbf_txt[15];
 346         int ccode;
 347
 348         if (!sch)
 349                 return -ENODEV;
 350
 351         CIO_TRACE_EVENT (2, "cancelIO");
 352         CIO_TRACE_EVENT (2, sch->dev.bus_id);
 353
 354         ccode = xsch (sch->irq);
 355
 356         sprintf (dbf_txt, "ccode:%d", ccode);
 357         CIO_TRACE_EVENT (2, dbf_txt);
 358
 359         switch (ccode) {
 360         case 0:         /* success */
 361                 /* Update information in scsw. */
 362                 stsch (sch->irq, &sch->schib);
 363                 return 0;
 364         case 1:         /* status pending */
 365                 return -EBUSY;
 366         case 2:         /* not applicable */
 367                 return -EINVAL;
 368         default:        /* not oper */
 369                 return -ENODEV;
 370         }
 371 }
 372
 373 /*
 374  * Function: cio_modify
 375  * Issues a "Modify Subchannel" on the specified subchannel
 376  */
 377 int
 378 cio_modify (struct subchannel *sch)
 379 {
 380         int ccode, retry, ret;
 381
 382         ret = 0;
 383         for (retry = 0; retry < 5; retry++) {
 384                 ccode = msch_err (sch->irq, &sch->schib);
 385                 if (ccode < 0)  /* -EIO if msch gets a program check. */
 386                         return ccode;
 387                 switch (ccode) {
 388                 case 0: /* successfull */
 389                         return 0;
 390                 case 1: /* status pending */
 391                         return -EBUSY;
 392                 case 2: /* busy */
 393                         udelay (100);   /* allow for recovery */
 394                         ret = -EBUSY;
 395                         break;
 396                 case 3: /* not operational */
 397                         return -ENODEV;
 398                 }
 399         }
 400         return ret;
 401 }
 402
 403 /*
 404  * Enable subchannel.
 405  */
 406 int
 407 cio_enable_subchannel (struct subchannel *sch, unsigned int isc)
 408 {
 409         char dbf_txt[15];
 410         int ccode;
 411         int retry;
 412         int ret;
 413
 414         CIO_TRACE_EVENT (2, "ensch");
 415         CIO_TRACE_EVENT (2, sch->dev.bus_id);
 416
 417         ccode = stsch (sch->irq, &sch->schib);
 418         if (ccode)
 419                 return -ENODEV;
 420
 421         for (retry = 5, ret = 0; retry > 0; retry--) {
 422                 sch->schib.pmcw.ena = 1;
 423                 sch->schib.pmcw.isc = isc;
 424                 sch->schib.pmcw.intparm = (__u32)(unsigned long)sch;
 425                 ret = cio_modify(sch);
 426                 if (ret == -ENODEV)
 427                         break;
 428                 if (ret == -EIO)
 429                         /*
 430                          * Got a program check in cio_modify. Try without
 431                          * the concurrent sense bit the next time.
 432                          */
 433                         sch->schib.pmcw.csense = 0;
 434                 if (ret == 0) {
 435                         stsch (sch->irq, &sch->schib);
 436                         if (sch->schib.pmcw.ena)
 437                                 break;
 438                 }
 439                 if (ret == -EBUSY) {
 440                         struct irb irb;
 441                         if (tsch(sch->irq, &irb) != 0)
 442                                 break;
 443                 }
 444         }
 445         sprintf (dbf_txt, "ret:%d", ret);
 446         CIO_TRACE_EVENT (2, dbf_txt);
 447         return ret;
 448 }
 449
 450 /*
 451  * Disable subchannel.
 452  */
 453 int
 454 cio_disable_subchannel (struct subchannel *sch)
 455 {
 456         char dbf_txt[15];
 457         int ccode;
 458         int retry;
 459         int ret;
 460
 461         CIO_TRACE_EVENT (2, "dissch");
 462         CIO_TRACE_EVENT (2, sch->dev.bus_id);
 463
 464         ccode = stsch (sch->irq, &sch->schib);
 465         if (ccode == 3)         /* Not operational. */
 466                 return -ENODEV;
 467
 468         if (sch->schib.scsw.actl != 0)
 469                 /*
 470                  * the disable function must not be called while there are
 471                  *  requests pending for completion !
 472                  */
 473                 return -EBUSY;
 474
 475         for (retry = 5, ret = 0; retry > 0; retry--) {
 476                 sch->schib.pmcw.ena = 0;
 477                 ret = cio_modify(sch);
 478                 if (ret == -ENODEV)
 479                         break;
 480                 if (ret == -EBUSY)
 481                         /*
 482                          * The subchannel is busy or status pending.
 483                          * We'll disable when the next interrupt was delivered
 484                          * via the state machine.
 485                          */
 486                         break;
 487                 if (ret == 0) {
 488                         stsch (sch->irq, &sch->schib);
 489                         if (!sch->schib.pmcw.ena)
 490                                 break;
 491                 }
 492         }
 493         sprintf (dbf_txt, "ret:%d", ret);
 494         CIO_TRACE_EVENT (2, dbf_txt);
 495         return ret;
 496 }
 497
 498 /*
 499  * cio_validate_subchannel()
 500  *
 501  * Find out subchannel type and initialize struct subchannel.
 502  * Return codes:
 503  *   SUBCHANNEL_TYPE_IO for a normal io subchannel
 504  *   SUBCHANNEL_TYPE_CHSC for a chsc subchannel
 505  *   SUBCHANNEL_TYPE_MESSAGE for a messaging subchannel
 506  *   SUBCHANNEL_TYPE_ADM for a adm(?) subchannel
 507  *   -ENXIO for non-defined subchannels
 508  *   -ENODEV for subchannels with invalid device number or blacklisted devices
 509  */
 510 int
 511 cio_validate_subchannel (struct subchannel *sch, unsigned int irq)
 512 {
 513         char dbf_txt[15];
 514         int ccode;
 515
 516         sprintf (dbf_txt, "valsch%x", irq);
 517         CIO_TRACE_EVENT (4, dbf_txt);
 518
 519         /* Nuke all fields. */
 520         memset(sch, 0, sizeof(struct subchannel));
 521
 522         spin_lock_init(&sch->lock);
 523
 524         /* Set a name for the subchannel */
 525         snprintf (sch->dev.bus_id, BUS_ID_SIZE, "0.0.%04x", irq);
 526
 527         /*
 528          * The first subchannel that is not-operational (ccode==3)
 529          *  indicates that there aren't any more devices available.
 530          */
 531         sch->irq = irq;
 532         ccode = stsch (irq, &sch->schib);
 533         if (ccode)
 534                 return -ENXIO;
 535
 536         /* Copy subchannel type from path management control word. */
 537         sch->st = sch->schib.pmcw.st;
 538
 539         /*
 540          * ... just being curious we check for non I/O subchannels
 541          */
 542         if (sch->st != 0) {
 543                 CIO_DEBUG(KERN_INFO, 0,
 544                           "Subchannel %04X reports "
 545                           "non-I/O subchannel type %04X\n",
 546                           sch->irq, sch->st);
 547                 /* We stop here for non-io subchannels. */
 548                 return sch->st;
 549         }
 550
 551         /* Initialization for io subchannels. */
 552         if (!sch->schib.pmcw.dnv)
 553                 /* io subchannel but device number is invalid. */
 554                 return -ENODEV;
 555
 556         /* Devno is valid. */
 557         if (is_blacklisted (sch->schib.pmcw.dev)) {
 558                 /*
 559                  * This device must not be known to Linux. So we simply
 560                  * say that there is no device and return ENODEV.
 561                  */
 562                 CIO_MSG_EVENT(0, "Blacklisted device detected "
 563                               "at devno %04X\n", sch->schib.pmcw.dev);
 564                 return -ENODEV;
 565         }
 566         sch->opm = 0xff;
 567         chsc_validate_chpids(sch);
 568         sch->lpm = sch->schib.pmcw.pim &
 569                 sch->schib.pmcw.pam &
 570                 sch->schib.pmcw.pom &
 571                 sch->opm;
 572
 573         CIO_DEBUG(KERN_INFO, 0,
 574                   "Detected device %04X on subchannel %04X"
 575                   " - PIM = %02X, PAM = %02X, POM = %02X\n",
 576                   sch->schib.pmcw.dev, sch->irq, sch->schib.pmcw.pim,
 577                   sch->schib.pmcw.pam, sch->schib.pmcw.pom);
 578
 579         /*
 580          * We now have to initially ...
 581          *  ... set "interruption subclass"
 582          *  ... enable "concurrent sense"
 583          *  ... enable "multipath mode" if more than one
 584          *        CHPID is available. This is done regardless
 585          *        whether multiple paths are available for us.
 586          */
 587         sch->schib.pmcw.isc = 3;        /* could be smth. else */
 588         sch->schib.pmcw.csense = 1;     /* concurrent sense */
 589         sch->schib.pmcw.ena = 0;
 590         if ((sch->lpm & (sch->lpm - 1)) != 0)
 591                 sch->schib.pmcw.mp = 1; /* multipath mode */
 592         return 0;
 593 }
 594
 595 /*
 596  * do_IRQ() handles all normal I/O device IRQ's (the special
 597  *          SMP cross-CPU interrupts have their own specific
 598  *          handlers).
 599  *
 600  */
 601 void
 602 do_IRQ (struct pt_regs *regs)
 603 {
 604         struct tpi_info *tpi_info;
 605         struct subchannel *sch;
 606         struct irb *irb;
 607
 608         irq_enter ();
 609         asm volatile ("mc 0,0");
 610         if (S390_lowcore.int_clock >= S390_lowcore.jiffy_timer)
 611                 /**
 612                  * Make sure that the i/o interrupt did not "overtake"
 613                  * the last HZ timer interrupt.
 614                  */
 615                 account_ticks(regs);
 616         /*
 617          * Get interrupt information from lowcore
 618          */
 619         tpi_info = (struct tpi_info *) __LC_SUBCHANNEL_ID;
 620         irb = (struct irb *) __LC_IRB;
 621         do {
 622                 kstat_cpu(smp_processor_id()).irqs[IO_INTERRUPT]++;
 623                 /*
 624                  * Non I/O-subchannel thin interrupts are processed differently
 625                  */
 626                 if (tpi_info->adapter_IO == 1 &&
 627                     tpi_info->int_type == IO_INTERRUPT_TYPE) {
 628                         do_adapter_IO();
 629                         continue;
 630                 }
 631                 sch = (struct subchannel *)(unsigned long)tpi_info->intparm;
 632                 if (sch)
 633                         spin_lock(&sch->lock);
 634                 /* Store interrupt response block to lowcore. */
 635                 if (tsch (tpi_info->irq, irb) == 0 && sch) {
 636                         /* Keep subchannel information word up to date. */
 637                         memcpy (&sch->schib.scsw, &irb->scsw,
 638                                 sizeof (irb->scsw));
 639                         /* Call interrupt handler if there is one. */
 640                         if (sch->driver && sch->driver->irq)
 641                                 sch->driver->irq(&sch->dev);
 642                 }
 643                 if (sch)
 644                         spin_unlock(&sch->lock);
 645                 /*
 646                  * Are more interrupts pending?
 647                  * If so, the tpi instruction will update the lowcore
 648                  * to hold the info for the next interrupt.
 649                  * We don't do this for VM because a tpi drops the cpu
 650                  * out of the sie which costs more cycles than it saves.
 651                  */
 652         } while (!MACHINE_IS_VM && tpi (NULL) != 0);
 653         irq_exit ();
 654 }
 655
 656 #ifdef CONFIG_CCW_CONSOLE
 657 static struct subchannel console_subchannel;
 658 static int console_subchannel_in_use;
 659
 660 /*
 661  * busy wait for the next interrupt on the console
 662  */
 663 void
 664 wait_cons_dev (void)
 665 {
 666         unsigned long cr6      __attribute__ ((aligned (8)));
 667         unsigned long save_cr6 __attribute__ ((aligned (8)));
 668
 669         /*
 670          * before entering the spinlock we may already have
 671          * processed the interrupt on a different CPU...
 672          */
 673         if (!console_subchannel_in_use)
 674                 return;
 675
 676         /* disable all but isc 7 (console device) */
 677         __ctl_store (save_cr6, 6, 6);
 678         cr6 = 0x01000000;
 679         __ctl_load (cr6, 6, 6);
 680
 681         do {
 682                 spin_unlock(&console_subchannel.lock);
 683                 if (!cio_tpi())
 684                         cpu_relax();
 685                 spin_lock(&console_subchannel.lock);
 686         } while (console_subchannel.schib.scsw.actl != 0);
 687         /*
 688          * restore previous isc value
 689          */
 690         __ctl_load (save_cr6, 6, 6);
 691 }
 692
 693 static int
 694 cio_console_irq(void)
 695 {
 696         int irq;
 697
 698         if (console_irq != -1) {
 699                 /* VM provided us with the irq number of the console. */
 700                 if (stsch(console_irq, &console_subchannel.schib) != 0 ||
 701                     !console_subchannel.schib.pmcw.dnv)
 702                         return -1;
 703                 console_devno = console_subchannel.schib.pmcw.dev;
 704         } else if (console_devno != -1) {
 705                 /* At least the console device number is known. */
 706                 for (irq = 0; irq < __MAX_SUBCHANNELS; irq++) {
 707                         if (stsch(irq, &console_subchannel.schib) != 0)
 708                                 break;
 709                         if (console_subchannel.schib.pmcw.dnv &&
 710                             console_subchannel.schib.pmcw.dev ==
 711                             console_devno) {
 712                                 console_irq = irq;
 713                                 break;
 714                         }
 715                 }
 716                 if (console_irq == -1)
 717                         return -1;
 718         } else {
 719                 /* unlike in 2.4, we cannot autoprobe here, since
 720                  * the channel subsystem is not fully initialized.
 721                  * With some luck, the HWC console can take over */
 722                 printk(KERN_WARNING "No ccw console found!\n");
 723                 return -1;
 724         }
 725         return console_irq;
 726 }
 727
 728 struct subchannel *
 729 cio_probe_console(void)
 730 {
 731         int irq, ret;
 732
 733         if (xchg(&console_subchannel_in_use, 1) != 0)
 734                 return ERR_PTR(-EBUSY);
 735         irq = cio_console_irq();
 736         if (irq == -1) {
 737                 console_subchannel_in_use = 0;
 738                 return ERR_PTR(-ENODEV);
 739         }
 740         memset(&console_subchannel, 0, sizeof(struct subchannel));
 741         ret = cio_validate_subchannel(&console_subchannel, irq);
 742         if (ret) {
 743                 console_subchannel_in_use = 0;
 744                 return ERR_PTR(-ENODEV);
 745         }
 746
 747         /*
 748          * enable console I/O-interrupt subclass 7
 749          */
 750         ctl_set_bit(6, 24);
 751         console_subchannel.schib.pmcw.isc = 7;
 752         console_subchannel.schib.pmcw.intparm =
 753                 (__u32)(unsigned long)&console_subchannel;
 754         ret = cio_modify(&console_subchannel);
 755         if (ret) {
 756                 console_subchannel_in_use = 0;
 757                 return ERR_PTR(ret);
 758         }
 759         return &console_subchannel;
 760 }
 761
 762 void
 763 cio_release_console(void)
 764 {
 765         console_subchannel.schib.pmcw.intparm = 0;
 766         cio_modify(&console_subchannel);
 767         ctl_clear_bit(6, 24);
 768         console_subchannel_in_use = 0;
 769 }
 770
 771 /* Bah... hack to catch console special sausages. */
 772 int
 773 cio_is_console(int irq)
 774 {
 775         if (!console_subchannel_in_use)
 776                 return 0;
 777         return (irq == console_subchannel.irq);
 778 }
 779
 780 struct subchannel *
 781 cio_get_console_subchannel(void)
 782 {
 783         if (!console_subchannel_in_use)
 784                 return 0;
 785         return &console_subchannel;
 786 }
 787
 788 #endif
 789 static inline int
 790 __disable_subchannel_easy(unsigned int schid, struct schib *schib)
 791 {
 792         int retry, cc;
 793
 794         cc = 0;
 795         for (retry=0;retry<3;retry++) {
 796                 schib->pmcw.ena = 0;
 797                 cc = msch(schid, schib);
 798                 if (cc)
 799                         return (cc==3?-ENODEV:-EBUSY);
 800                 stsch(schid, schib);
 801                 if (!schib->pmcw.ena)
 802                         return 0;
 803         }
 804         return -EBUSY; /* uhm... */
 805 }
 806
 807 static inline int
 808 __clear_subchannel_easy(unsigned int schid)
 809 {
 810         int retry;
 811
 812         if (csch(schid))
 813                 return -ENODEV;
 814         for (retry=0;retry<20;retry++) {
 815                 struct tpi_info ti;
 816
 817                 if (tpi(&ti)) {
 818                         tsch(schid, (struct irb *)__LC_IRB);
 819                         return 0;
 820                 }
 821                 udelay(100);
 822         }
 823         return -EBUSY;
 824 }
 825
 826 extern void do_reipl(unsigned long devno);
 827
 828 /* Clear all subchannels. */
 829 void
 830 clear_all_subchannels(void)
 831 {
 832         unsigned int schid;
 833
 834         local_irq_disable();
 835         for (schid=0;schid<=highest_subchannel;schid++) {
 836                 struct schib schib;
 837                 if (stsch(schid, &schib))
 838                         break; /* break out of the loop */
 839                 if (!schib.pmcw.ena)
 840                         continue;
 841                 switch(__disable_subchannel_easy(schid, &schib)) {
 842                 case 0:
 843                 case -ENODEV:
 844                         break;
 845                 default: /* -EBUSY */
 846                         if (__clear_subchannel_easy(schid))
 847                                 break; /* give up... jump out of switch */
 848                         stsch(schid, &schib);
 849                         __disable_subchannel_easy(schid, &schib);
 850                 }
 851         }
 852 }
 853
 854 /* Make sure all subchannels are quiet before we re-ipl an lpar. */
 855 void
 856 reipl(unsigned long devno)
 857 {
 858         clear_all_subchannels();
 859         do_reipl(devno);
 860 }