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