drivers/s390/cio/cio.c

   1 // SPDX-License-Identifier: GPL-2.0
   2 /*
   3  *   S/390 common I/O routines -- low level i/o calls
   4  *
   5  *    Copyright IBM Corp. 1999, 2008
   6  *    Author(s): Ingo Adlung (adlung@de.ibm.com)
   7  *               Cornelia Huck (cornelia.huck@de.ibm.com)
   8  *               Arnd Bergmann (arndb@de.ibm.com)
   9  *               Martin Schwidefsky (schwidefsky@de.ibm.com)
  10  */
  11
  12 #define KMSG_COMPONENT "cio"
  13 #define pr_fmt(fmt) KMSG_COMPONENT ": " fmt
  14
  15 #include <linux/ftrace.h>
  16 #include <linux/module.h>
  17 #include <linux/init.h>
  18 #include <linux/slab.h>
  19 #include <linux/device.h>
  20 #include <linux/kernel_stat.h>
  21 #include <linux/interrupt.h>
  22 #include <linux/irq.h>
  23 #include <asm/cio.h>
  24 #include <asm/delay.h>
  25 #include <asm/irq.h>
  26 #include <asm/irq_regs.h>
  27 #include <asm/setup.h>
  28 #include <asm/ipl.h>
  29 #include <asm/chpid.h>
  30 #include <asm/airq.h>
  31 #include <asm/isc.h>
  32 #include <linux/sched/cputime.h>
  33 #include <asm/fcx.h>
  34 #include <asm/nmi.h>
  35 #include <asm/crw.h>
  36 #include "cio.h"
  37 #include "css.h"
  38 #include "chsc.h"
  39 #include "ioasm.h"
  40 #include "io_sch.h"
  41 #include "blacklist.h"
  42 #include "cio_debug.h"
  43 #include "chp.h"
  44 #include "trace.h"
  45
  46 debug_info_t *cio_debug_msg_id;
  47 debug_info_t *cio_debug_trace_id;
  48 debug_info_t *cio_debug_crw_id;
  49
  50 DEFINE_PER_CPU_ALIGNED(struct irb, cio_irb);
  51 EXPORT_PER_CPU_SYMBOL(cio_irb);
  52
  53 /*
  54  * Function: cio_debug_init
  55  * Initializes three debug logs for common I/O:
  56  * - cio_msg logs generic cio messages
  57  * - cio_trace logs the calling of different functions
  58  * - cio_crw logs machine check related cio messages
  59  */
  60 static int __init cio_debug_init(void)
  61 {
  62         cio_debug_msg_id = debug_register("cio_msg", 16, 1, 11 * sizeof(long));
  63         if (!cio_debug_msg_id)
  64                 goto out_unregister;
  65         debug_register_view(cio_debug_msg_id, &debug_sprintf_view);
  66         debug_set_level(cio_debug_msg_id, 2);
  67         cio_debug_trace_id = debug_register("cio_trace", 16, 1, 16);
  68         if (!cio_debug_trace_id)
  69                 goto out_unregister;
  70         debug_register_view(cio_debug_trace_id, &debug_hex_ascii_view);
  71         debug_set_level(cio_debug_trace_id, 2);
  72         cio_debug_crw_id = debug_register("cio_crw", 8, 1, 8 * sizeof(long));
  73         if (!cio_debug_crw_id)
  74                 goto out_unregister;
  75         debug_register_view(cio_debug_crw_id, &debug_sprintf_view);
  76         debug_set_level(cio_debug_crw_id, 4);
  77         return 0;
  78
  79 out_unregister:
  80         debug_unregister(cio_debug_msg_id);
  81         debug_unregister(cio_debug_trace_id);
  82         debug_unregister(cio_debug_crw_id);
  83         return -1;
  84 }
  85
  86 arch_initcall (cio_debug_init);
  87
  88 int cio_set_options(struct subchannel *sch, int flags)
  89 {
  90         struct io_subchannel_private *priv = to_io_private(sch);
  91
  92         priv->options.suspend = (flags & DOIO_ALLOW_SUSPEND) != 0;
  93         priv->options.prefetch = (flags & DOIO_DENY_PREFETCH) != 0;
  94         priv->options.inter = (flags & DOIO_SUPPRESS_INTER) != 0;
  95         return 0;
  96 }
  97
  98 static int
  99 cio_start_handle_notoper(struct subchannel *sch, __u8 lpm)
 100 {
 101         char dbf_text[15];
 102
 103         if (lpm != 0)
 104                 sch->lpm &= ~lpm;
 105         else
 106                 sch->lpm = 0;
 107
 108         CIO_MSG_EVENT(2, "cio_start: 'not oper' status for "
 109                       "subchannel 0.%x.%04x!\n", sch->schid.ssid,
 110                       sch->schid.sch_no);
 111
 112         if (cio_update_schib(sch))
 113                 return -ENODEV;
 114
 115         sprintf(dbf_text, "no%s", dev_name(&sch->dev));
 116         CIO_TRACE_EVENT(0, dbf_text);
 117         CIO_HEX_EVENT(0, &sch->schib, sizeof (struct schib));
 118
 119         return (sch->lpm ? -EACCES : -ENODEV);
 120 }
 121
 122 int
 123 cio_start_key (struct subchannel *sch,  /* subchannel structure */
 124                struct ccw1 * cpa,       /* logical channel prog addr */
 125                __u8 lpm,                /* logical path mask */
 126                __u8 key)                /* storage key */
 127 {
 128         struct io_subchannel_private *priv = to_io_private(sch);
 129         union orb *orb = &priv->orb;
 130         int ccode;
 131
 132         CIO_TRACE_EVENT(5, "stIO");
 133         CIO_TRACE_EVENT(5, dev_name(&sch->dev));
 134
 135         memset(orb, 0, sizeof(union orb));
 136         /* sch is always under 2G. */
 137         orb->cmd.intparm = (u32)(addr_t)sch;
 138         orb->cmd.fmt = 1;
 139
 140         orb->cmd.pfch = priv->options.prefetch == 0;
 141         orb->cmd.spnd = priv->options.suspend;
 142         orb->cmd.ssic = priv->options.suspend && priv->options.inter;
 143         orb->cmd.lpm = (lpm != 0) ? lpm : sch->lpm;
 144         /*
 145          * for 64 bit we always support 64 bit IDAWs with 4k page size only
 146          */
 147         orb->cmd.c64 = 1;
 148         orb->cmd.i2k = 0;
 149         orb->cmd.key = key >> 4;
 150         /* issue "Start Subchannel" */
 151         orb->cmd.cpa = (__u32) __pa(cpa);
 152         ccode = ssch(sch->schid, orb);
 153
 154         /* process condition code */
 155         CIO_HEX_EVENT(5, &ccode, sizeof(ccode));
 156
 157         switch (ccode) {
 158         case 0:
 159                 /*
 160                  * initialize device status information
 161                  */
 162                 sch->schib.scsw.cmd.actl |= SCSW_ACTL_START_PEND;
 163                 return 0;
 164         case 1:         /* status pending */
 165         case 2:         /* busy */
 166                 return -EBUSY;
 167         case 3:         /* device/path not operational */
 168                 return cio_start_handle_notoper(sch, lpm);
 169         default:
 170                 return ccode;
 171         }
 172 }
 173 EXPORT_SYMBOL_GPL(cio_start_key);
 174
 175 int
 176 cio_start (struct subchannel *sch, struct ccw1 *cpa, __u8 lpm)
 177 {
 178         return cio_start_key(sch, cpa, lpm, PAGE_DEFAULT_KEY);
 179 }
 180 EXPORT_SYMBOL_GPL(cio_start);
 181
 182 /*
 183  * resume suspended I/O operation
 184  */
 185 int
 186 cio_resume (struct subchannel *sch)
 187 {
 188         int ccode;
 189
 190         CIO_TRACE_EVENT(4, "resIO");
 191         CIO_TRACE_EVENT(4, dev_name(&sch->dev));
 192
 193         ccode = rsch (sch->schid);
 194
 195         CIO_HEX_EVENT(4, &ccode, sizeof(ccode));
 196
 197         switch (ccode) {
 198         case 0:
 199                 sch->schib.scsw.cmd.actl |= SCSW_ACTL_RESUME_PEND;
 200                 return 0;
 201         case 1:
 202                 return -EBUSY;
 203         case 2:
 204                 return -EINVAL;
 205         default:
 206                 /*
 207                  * useless to wait for request completion
 208                  *  as device is no longer operational !
 209                  */
 210                 return -ENODEV;
 211         }
 212 }
 213 EXPORT_SYMBOL_GPL(cio_resume);
 214
 215 /*
 216  * halt I/O operation
 217  */
 218 int
 219 cio_halt(struct subchannel *sch)
 220 {
 221         int ccode;
 222
 223         if (!sch)
 224                 return -ENODEV;
 225
 226         CIO_TRACE_EVENT(2, "haltIO");
 227         CIO_TRACE_EVENT(2, dev_name(&sch->dev));
 228
 229         /*
 230          * Issue "Halt subchannel" and process condition code
 231          */
 232         ccode = hsch (sch->schid);
 233
 234         CIO_HEX_EVENT(2, &ccode, sizeof(ccode));
 235
 236         switch (ccode) {
 237         case 0:
 238                 sch->schib.scsw.cmd.actl |= SCSW_ACTL_HALT_PEND;
 239                 return 0;
 240         case 1:         /* status pending */
 241         case 2:         /* busy */
 242                 return -EBUSY;
 243         default:                /* device not operational */
 244                 return -ENODEV;
 245         }
 246 }
 247 EXPORT_SYMBOL_GPL(cio_halt);
 248
 249 /*
 250  * Clear I/O operation
 251  */
 252 int
 253 cio_clear(struct subchannel *sch)
 254 {
 255         int ccode;
 256
 257         if (!sch)
 258                 return -ENODEV;
 259
 260         CIO_TRACE_EVENT(2, "clearIO");
 261         CIO_TRACE_EVENT(2, dev_name(&sch->dev));
 262
 263         /*
 264          * Issue "Clear subchannel" and process condition code
 265          */
 266         ccode = csch (sch->schid);
 267
 268         CIO_HEX_EVENT(2, &ccode, sizeof(ccode));
 269
 270         switch (ccode) {
 271         case 0:
 272                 sch->schib.scsw.cmd.actl |= SCSW_ACTL_CLEAR_PEND;
 273                 return 0;
 274         default:                /* device not operational */
 275                 return -ENODEV;
 276         }
 277 }
 278 EXPORT_SYMBOL_GPL(cio_clear);
 279
 280 /*
 281  * Function: cio_cancel
 282  * Issues a "Cancel Subchannel" on the specified subchannel
 283  * Note: We don't need any fancy intparms and flags here
 284  *       since xsch is executed synchronously.
 285  * Only for common I/O internal use as for now.
 286  */
 287 int
 288 cio_cancel (struct subchannel *sch)
 289 {
 290         int ccode;
 291
 292         if (!sch)
 293                 return -ENODEV;
 294
 295         CIO_TRACE_EVENT(2, "cancelIO");
 296         CIO_TRACE_EVENT(2, dev_name(&sch->dev));
 297
 298         ccode = xsch (sch->schid);
 299
 300         CIO_HEX_EVENT(2, &ccode, sizeof(ccode));
 301
 302         switch (ccode) {
 303         case 0:         /* success */
 304                 /* Update information in scsw. */
 305                 if (cio_update_schib(sch))
 306                         return -ENODEV;
 307                 return 0;
 308         case 1:         /* status pending */
 309                 return -EBUSY;
 310         case 2:         /* not applicable */
 311                 return -EINVAL;
 312         default:        /* not oper */
 313                 return -ENODEV;
 314         }
 315 }
 316 EXPORT_SYMBOL_GPL(cio_cancel);
 317
 318 /**
 319  * cio_cancel_halt_clear - Cancel running I/O by performing cancel, halt
 320  * and clear ordinally if subchannel is valid.
 321  * @sch: subchannel on which to perform the cancel_halt_clear operation
 322  * @iretry: the number of the times remained to retry the next operation
 323  *
 324  * This should be called repeatedly since halt/clear are asynchronous
 325  * operations. We do one try with cio_cancel, three tries with cio_halt,
 326  * 255 tries with cio_clear. The caller should initialize @iretry with
 327  * the value 255 for its first call to this, and keep using the same
 328  * @iretry in the subsequent calls until it gets a non -EBUSY return.
 329  *
 330  * Returns 0 if device now idle, -ENODEV for device not operational,
 331  * -EBUSY if an interrupt is expected (either from halt/clear or from a
 332  * status pending), and -EIO if out of retries.
 333  */
 334 int cio_cancel_halt_clear(struct subchannel *sch, int *iretry)
 335 {
 336         int ret;
 337
 338         if (cio_update_schib(sch))
 339                 return -ENODEV;
 340         if (!sch->schib.pmcw.ena)
 341                 /* Not operational -> done. */
 342                 return 0;
 343         /* Stage 1: cancel io. */
 344         if (!(scsw_actl(&sch->schib.scsw) & SCSW_ACTL_HALT_PEND) &&
 345             !(scsw_actl(&sch->schib.scsw) & SCSW_ACTL_CLEAR_PEND)) {
 346                 if (!scsw_is_tm(&sch->schib.scsw)) {
 347                         ret = cio_cancel(sch);
 348                         if (ret != -EINVAL)
 349                                 return ret;
 350                 }
 351                 /*
 352                  * Cancel io unsuccessful or not applicable (transport mode).
 353                  * Continue with asynchronous instructions.
 354                  */
 355                 *iretry = 3;    /* 3 halt retries. */
 356         }
 357         /* Stage 2: halt io. */
 358         if (!(scsw_actl(&sch->schib.scsw) & SCSW_ACTL_CLEAR_PEND)) {
 359                 if (*iretry) {
 360                         *iretry -= 1;
 361                         ret = cio_halt(sch);
 362                         if (ret != -EBUSY)
 363                                 return (ret == 0) ? -EBUSY : ret;
 364                 }
 365                 /* Halt io unsuccessful. */
 366                 *iretry = 255;  /* 255 clear retries. */
 367         }
 368         /* Stage 3: clear io. */
 369         if (*iretry) {
 370                 *iretry -= 1;
 371                 ret = cio_clear(sch);
 372                 return (ret == 0) ? -EBUSY : ret;
 373         }
 374         /* Function was unsuccessful */
 375         return -EIO;
 376 }
 377 EXPORT_SYMBOL_GPL(cio_cancel_halt_clear);
 378
 379 static void cio_apply_config(struct subchannel *sch, struct schib *schib)
 380 {
 381         schib->pmcw.intparm = sch->config.intparm;
 382         schib->pmcw.mbi = sch->config.mbi;
 383         schib->pmcw.isc = sch->config.isc;
 384         schib->pmcw.ena = sch->config.ena;
 385         schib->pmcw.mme = sch->config.mme;
 386         schib->pmcw.mp = sch->config.mp;
 387         schib->pmcw.csense = sch->config.csense;
 388         schib->pmcw.mbfc = sch->config.mbfc;
 389         if (sch->config.mbfc)
 390                 schib->mba = sch->config.mba;
 391 }
 392
 393 static int cio_check_config(struct subchannel *sch, struct schib *schib)
 394 {
 395         return (schib->pmcw.intparm == sch->config.intparm) &&
 396                 (schib->pmcw.mbi == sch->config.mbi) &&
 397                 (schib->pmcw.isc == sch->config.isc) &&
 398                 (schib->pmcw.ena == sch->config.ena) &&
 399                 (schib->pmcw.mme == sch->config.mme) &&
 400                 (schib->pmcw.mp == sch->config.mp) &&
 401                 (schib->pmcw.csense == sch->config.csense) &&
 402                 (schib->pmcw.mbfc == sch->config.mbfc) &&
 403                 (!sch->config.mbfc || (schib->mba == sch->config.mba));
 404 }
 405
 406 /*
 407  * cio_commit_config - apply configuration to the subchannel
 408  */
 409 int cio_commit_config(struct subchannel *sch)
 410 {
 411         int ccode, retry, ret = 0;
 412         struct schib schib;
 413         struct irb irb;
 414
 415         if (stsch(sch->schid, &schib) || !css_sch_is_valid(&schib))
 416                 return -ENODEV;
 417
 418         for (retry = 0; retry < 5; retry++) {
 419                 /* copy desired changes to local schib */
 420                 cio_apply_config(sch, &schib);
 421                 ccode = msch(sch->schid, &schib);
 422                 if (ccode < 0) /* -EIO if msch gets a program check. */
 423                         return ccode;
 424                 switch (ccode) {
 425                 case 0: /* successful */
 426                         if (stsch(sch->schid, &schib) ||
 427                             !css_sch_is_valid(&schib))
 428                                 return -ENODEV;
 429                         if (cio_check_config(sch, &schib)) {
 430                                 /* commit changes from local schib */
 431                                 memcpy(&sch->schib, &schib, sizeof(schib));
 432                                 return 0;
 433                         }
 434                         ret = -EAGAIN;
 435                         break;
 436                 case 1: /* status pending */
 437                         ret = -EBUSY;
 438                         if (tsch(sch->schid, &irb))
 439                                 return ret;
 440                         break;
 441                 case 2: /* busy */
 442                         udelay(100); /* allow for recovery */
 443                         ret = -EBUSY;
 444                         break;
 445                 case 3: /* not operational */
 446                         return -ENODEV;
 447                 }
 448         }
 449         return ret;
 450 }
 451 EXPORT_SYMBOL_GPL(cio_commit_config);
 452
 453 /**
 454  * cio_update_schib - Perform stsch and update schib if subchannel is valid.
 455  * @sch: subchannel on which to perform stsch
 456  * Return zero on success, -ENODEV otherwise.
 457  */
 458 int cio_update_schib(struct subchannel *sch)
 459 {
 460         struct schib schib;
 461
 462         if (stsch(sch->schid, &schib) || !css_sch_is_valid(&schib))
 463                 return -ENODEV;
 464
 465         memcpy(&sch->schib, &schib, sizeof(schib));
 466         return 0;
 467 }
 468 EXPORT_SYMBOL_GPL(cio_update_schib);
 469
 470 /**
 471  * cio_enable_subchannel - enable a subchannel.
 472  * @sch: subchannel to be enabled
 473  * @intparm: interruption parameter to set
 474  */
 475 int cio_enable_subchannel(struct subchannel *sch, u32 intparm)
 476 {
 477         int ret;
 478
 479         CIO_TRACE_EVENT(2, "ensch");
 480         CIO_TRACE_EVENT(2, dev_name(&sch->dev));
 481
 482         if (sch_is_pseudo_sch(sch))
 483                 return -EINVAL;
 484         if (cio_update_schib(sch))
 485                 return -ENODEV;
 486
 487         sch->config.ena = 1;
 488         sch->config.isc = sch->isc;
 489         sch->config.intparm = intparm;
 490
 491         ret = cio_commit_config(sch);
 492         if (ret == -EIO) {
 493                 /*
 494                  * Got a program check in msch. Try without
 495                  * the concurrent sense bit the next time.
 496                  */
 497                 sch->config.csense = 0;
 498                 ret = cio_commit_config(sch);
 499         }
 500         CIO_HEX_EVENT(2, &ret, sizeof(ret));
 501         return ret;
 502 }
 503 EXPORT_SYMBOL_GPL(cio_enable_subchannel);
 504
 505 /**
 506  * cio_disable_subchannel - disable a subchannel.
 507  * @sch: subchannel to disable
 508  */
 509 int cio_disable_subchannel(struct subchannel *sch)
 510 {
 511         int ret;
 512
 513         CIO_TRACE_EVENT(2, "dissch");
 514         CIO_TRACE_EVENT(2, dev_name(&sch->dev));
 515
 516         if (sch_is_pseudo_sch(sch))
 517                 return 0;
 518         if (cio_update_schib(sch))
 519                 return -ENODEV;
 520
 521         sch->config.ena = 0;
 522         ret = cio_commit_config(sch);
 523
 524         CIO_HEX_EVENT(2, &ret, sizeof(ret));
 525         return ret;
 526 }
 527 EXPORT_SYMBOL_GPL(cio_disable_subchannel);
 528
 529 /*
 530  * do_cio_interrupt() handles all normal I/O device IRQ's
 531  */
 532 static irqreturn_t do_cio_interrupt(int irq, void *dummy)
 533 {
 534         struct tpi_info *tpi_info;
 535         struct subchannel *sch;
 536         struct irb *irb;
 537
 538         set_cpu_flag(CIF_NOHZ_DELAY);
 539         tpi_info = (struct tpi_info *) &get_irq_regs()->int_code;
 540         trace_s390_cio_interrupt(tpi_info);
 541         irb = this_cpu_ptr(&cio_irb);
 542         sch = (struct subchannel *)(unsigned long) tpi_info->intparm;
 543         if (!sch) {
 544                 /* Clear pending interrupt condition. */
 545                 inc_irq_stat(IRQIO_CIO);
 546                 tsch(tpi_info->schid, irb);
 547                 return IRQ_HANDLED;
 548         }
 549         spin_lock(sch->lock);
 550         /* Store interrupt response block to lowcore. */
 551         if (tsch(tpi_info->schid, irb) == 0) {
 552                 /* Keep subchannel information word up to date. */
 553                 memcpy (&sch->schib.scsw, &irb->scsw, sizeof (irb->scsw));
 554                 /* Call interrupt handler if there is one. */
 555                 if (sch->driver && sch->driver->irq)
 556                         sch->driver->irq(sch);
 557                 else
 558                         inc_irq_stat(IRQIO_CIO);
 559         } else
 560                 inc_irq_stat(IRQIO_CIO);
 561         spin_unlock(sch->lock);
 562
 563         return IRQ_HANDLED;
 564 }
 565
 566 static struct irqaction io_interrupt = {
 567         .name    = "IO",
 568         .handler = do_cio_interrupt,
 569 };
 570
 571 void __init init_cio_interrupts(void)
 572 {
 573         irq_set_chip_and_handler(IO_INTERRUPT,
 574                                  &dummy_irq_chip, handle_percpu_irq);
 575         setup_irq(IO_INTERRUPT, &io_interrupt);
 576 }
 577
 578 #ifdef CONFIG_CCW_CONSOLE
 579 static struct subchannel *console_sch;
 580 static struct lock_class_key console_sch_key;
 581
 582 /*
 583  * Use cio_tsch to update the subchannel status and call the interrupt handler
 584  * if status had been pending. Called with the subchannel's lock held.
 585  */
 586 void cio_tsch(struct subchannel *sch)
 587 {
 588         struct irb *irb;
 589         int irq_context;
 590
 591         irb = this_cpu_ptr(&cio_irb);
 592         /* Store interrupt response block to lowcore. */
 593         if (tsch(sch->schid, irb) != 0)
 594                 /* Not status pending or not operational. */
 595                 return;
 596         memcpy(&sch->schib.scsw, &irb->scsw, sizeof(union scsw));
 597         /* Call interrupt handler with updated status. */
 598         irq_context = in_interrupt();
 599         if (!irq_context) {
 600                 local_bh_disable();
 601                 irq_enter();
 602         }
 603         kstat_incr_irq_this_cpu(IO_INTERRUPT);
 604         if (sch->driver && sch->driver->irq)
 605                 sch->driver->irq(sch);
 606         else
 607                 inc_irq_stat(IRQIO_CIO);
 608         if (!irq_context) {
 609                 irq_exit();
 610                 _local_bh_enable();
 611         }
 612 }
 613
 614 static int cio_test_for_console(struct subchannel_id schid, void *data)
 615 {
 616         struct schib schib;
 617
 618         if (stsch(schid, &schib) != 0)
 619                 return -ENXIO;
 620         if ((schib.pmcw.st == SUBCHANNEL_TYPE_IO) && schib.pmcw.dnv &&
 621             (schib.pmcw.dev == console_devno)) {
 622                 console_irq = schid.sch_no;
 623                 return 1; /* found */
 624         }
 625         return 0;
 626 }
 627
 628 static int cio_get_console_sch_no(void)
 629 {
 630         struct subchannel_id schid;
 631         struct schib schib;
 632
 633         init_subchannel_id(&schid);
 634         if (console_irq != -1) {
 635                 /* VM provided us with the irq number of the console. */
 636                 schid.sch_no = console_irq;
 637                 if (stsch(schid, &schib) != 0 ||
 638                     (schib.pmcw.st != SUBCHANNEL_TYPE_IO) || !schib.pmcw.dnv)
 639                         return -1;
 640                 console_devno = schib.pmcw.dev;
 641         } else if (console_devno != -1) {
 642                 /* At least the console device number is known. */
 643                 for_each_subchannel(cio_test_for_console, NULL);
 644         }
 645         return console_irq;
 646 }
 647
 648 struct subchannel *cio_probe_console(void)
 649 {
 650         struct subchannel_id schid;
 651         struct subchannel *sch;
 652         struct schib schib;
 653         int sch_no, ret;
 654
 655         sch_no = cio_get_console_sch_no();
 656         if (sch_no == -1) {
 657                 pr_warn("No CCW console was found\n");
 658                 return ERR_PTR(-ENODEV);
 659         }
 660         init_subchannel_id(&schid);
 661         schid.sch_no = sch_no;
 662         ret = stsch(schid, &schib);
 663         if (ret)
 664                 return ERR_PTR(-ENODEV);
 665
 666         sch = css_alloc_subchannel(schid, &schib);
 667         if (IS_ERR(sch))
 668                 return sch;
 669
 670         lockdep_set_class(sch->lock, &console_sch_key);
 671         isc_register(CONSOLE_ISC);
 672         sch->config.isc = CONSOLE_ISC;
 673         sch->config.intparm = (u32)(addr_t)sch;
 674         ret = cio_commit_config(sch);
 675         if (ret) {
 676                 isc_unregister(CONSOLE_ISC);
 677                 put_device(&sch->dev);
 678                 return ERR_PTR(ret);
 679         }
 680         console_sch = sch;
 681         return sch;
 682 }
 683
 684 int cio_is_console(struct subchannel_id schid)
 685 {
 686         if (!console_sch)
 687                 return 0;
 688         return schid_equal(&schid, &console_sch->schid);
 689 }
 690
 691 void cio_register_early_subchannels(void)
 692 {
 693         int ret;
 694
 695         if (!console_sch)
 696                 return;
 697
 698         ret = css_register_subchannel(console_sch);
 699         if (ret)
 700                 put_device(&console_sch->dev);
 701 }
 702 #endif /* CONFIG_CCW_CONSOLE */
 703
 704 /**
 705  * cio_tm_start_key - perform start function
 706  * @sch: subchannel on which to perform the start function
 707  * @tcw: transport-command word to be started
 708  * @lpm: mask of paths to use
 709  * @key: storage key to use for storage access
 710  *
 711  * Start the tcw on the given subchannel. Return zero on success, non-zero
 712  * otherwise.
 713  */
 714 int cio_tm_start_key(struct subchannel *sch, struct tcw *tcw, u8 lpm, u8 key)
 715 {
 716         int cc;
 717         union orb *orb = &to_io_private(sch)->orb;
 718
 719         memset(orb, 0, sizeof(union orb));
 720         orb->tm.intparm = (u32) (addr_t) sch;
 721         orb->tm.key = key >> 4;
 722         orb->tm.b = 1;
 723         orb->tm.lpm = lpm ? lpm : sch->lpm;
 724         orb->tm.tcw = (u32) (addr_t) tcw;
 725         cc = ssch(sch->schid, orb);
 726         switch (cc) {
 727         case 0:
 728                 return 0;
 729         case 1:
 730         case 2:
 731                 return -EBUSY;
 732         default:
 733                 return cio_start_handle_notoper(sch, lpm);
 734         }
 735 }
 736 EXPORT_SYMBOL_GPL(cio_tm_start_key);
 737
 738 /**
 739  * cio_tm_intrg - perform interrogate function
 740  * @sch: subchannel on which to perform the interrogate function
 741  *
 742  * If the specified subchannel is running in transport-mode, perform the
 743  * interrogate function. Return zero on success, non-zero otherwie.
 744  */
 745 int cio_tm_intrg(struct subchannel *sch)
 746 {
 747         int cc;
 748
 749         if (!to_io_private(sch)->orb.tm.b)
 750                 return -EINVAL;
 751         cc = xsch(sch->schid);
 752         switch (cc) {
 753         case 0:
 754         case 2:
 755                 return 0;
 756         case 1:
 757                 return -EBUSY;
 758         default:
 759                 return -ENODEV;
 760         }
 761 }
 762 EXPORT_SYMBOL_GPL(cio_tm_intrg);