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cio.c

/*
 *  drivers/s390/cio/cio.c
 *   S/390 common I/O routines -- low level i/o calls
 *
 *    Copyright (C) IBM Corp. 1999,2006
 *    Author(s): Ingo Adlung (adlung@de.ibm.com)
 *           Cornelia Huck (cornelia.huck@de.ibm.com)
 *           Arnd Bergmann (arndb@de.ibm.com)
 *           Martin Schwidefsky (schwidefsky@de.ibm.com)
 */

#include <linux/module.h>
#include <linux/init.h>
#include <linux/slab.h>
#include <linux/device.h>
#include <linux/kernel_stat.h>
#include <linux/interrupt.h>
#include <asm/cio.h>
#include <asm/delay.h>
#include <asm/irq.h>
#include <asm/irq_regs.h>
#include <asm/setup.h>
#include <asm/reset.h>
#include <asm/ipl.h>
#include <asm/chpid.h>
#include "airq.h"
#include "cio.h"
#include "css.h"
#include "chsc.h"
#include "ioasm.h"
#include "blacklist.h"
#include "cio_debug.h"
#include "chp.h"
#include "../s390mach.h"

debug_info_t *cio_debug_msg_id;
debug_info_t *cio_debug_trace_id;
debug_info_t *cio_debug_crw_id;

int cio_show_msg;

static int __init
cio_setup (char *parm)
{
      if (!strcmp (parm, "yes"))
            cio_show_msg = 1;
      else if (!strcmp (parm, "no"))
            cio_show_msg = 0;
      else
            printk(KERN_ERR "cio: cio_setup: "
                   "invalid cio_msg parameter '%s'", parm);
      return 1;
}

__setup ("cio_msg=", cio_setup);

/*
 * Function: cio_debug_init
 * Initializes three debug logs (under /proc/s390dbf) for common I/O:
 * - cio_msg logs the messages which are printk'ed when CONFIG_DEBUG_IO is on
 * - cio_trace logs the calling of different functions
 * - cio_crw logs the messages which are printk'ed when CONFIG_DEBUG_CRW is on
 * debug levels depend on CONFIG_DEBUG_IO resp. CONFIG_DEBUG_CRW
 */
static int __init
cio_debug_init (void)
{
      cio_debug_msg_id = debug_register ("cio_msg", 16, 4, 16*sizeof (long));
      if (!cio_debug_msg_id)
            goto out_unregister;
      debug_register_view (cio_debug_msg_id, &debug_sprintf_view);
      debug_set_level (cio_debug_msg_id, 2);
      cio_debug_trace_id = debug_register ("cio_trace", 16, 4, 16);
      if (!cio_debug_trace_id)
            goto out_unregister;
      debug_register_view (cio_debug_trace_id, &debug_hex_ascii_view);
      debug_set_level (cio_debug_trace_id, 2);
      cio_debug_crw_id = debug_register ("cio_crw", 4, 4, 16*sizeof (long));
      if (!cio_debug_crw_id)
            goto out_unregister;
      debug_register_view (cio_debug_crw_id, &debug_sprintf_view);
      debug_set_level (cio_debug_crw_id, 2);
      return 0;

out_unregister:
      if (cio_debug_msg_id)
            debug_unregister (cio_debug_msg_id);
      if (cio_debug_trace_id)
            debug_unregister (cio_debug_trace_id);
      if (cio_debug_crw_id)
            debug_unregister (cio_debug_crw_id);
      printk(KERN_WARNING"cio: could not initialize debugging\n");
      return -1;
}

arch_initcall (cio_debug_init);

int
cio_set_options (struct subchannel *sch, int flags)
{
       sch->options.suspend = (flags & DOIO_ALLOW_SUSPEND) != 0;
       sch->options.prefetch = (flags & DOIO_DENY_PREFETCH) != 0;
       sch->options.inter = (flags & DOIO_SUPPRESS_INTER) != 0;
       return 0;
}

/* FIXME: who wants to use this? */
int
cio_get_options (struct subchannel *sch)
{
       int flags;

       flags = 0;
       if (sch->options.suspend)
            flags |= DOIO_ALLOW_SUSPEND;
       if (sch->options.prefetch)
            flags |= DOIO_DENY_PREFETCH;
       if (sch->options.inter)
            flags |= DOIO_SUPPRESS_INTER;
       return flags;
}

/*
 * Use tpi to get a pending interrupt, call the interrupt handler and
 * return a pointer to the subchannel structure.
 */
static int
cio_tpi(void)
{
      struct tpi_info *tpi_info;
      struct subchannel *sch;
      struct irb *irb;

      tpi_info = (struct tpi_info *) __LC_SUBCHANNEL_ID;
      if (tpi (NULL) != 1)
            return 0;
      irb = (struct irb *) __LC_IRB;
      /* Store interrupt response block to lowcore. */
      if (tsch (tpi_info->schid, irb) != 0)
            /* Not status pending or not operational. */
            return 1;
      sch = (struct subchannel *)(unsigned long)tpi_info->intparm;
      if (!sch)
            return 1;
      local_bh_disable();
      irq_enter ();
      spin_lock(sch->lock);
      memcpy (&sch->schib.scsw, &irb->scsw, sizeof (struct scsw));
      if (sch->driver && sch->driver->irq)
            sch->driver->irq(&sch->dev);
      spin_unlock(sch->lock);
      irq_exit ();
      _local_bh_enable();
      return 1;
}

static int
cio_start_handle_notoper(struct subchannel *sch, __u8 lpm)
{
      char dbf_text[15];

      if (lpm != 0)
            sch->lpm &= ~lpm;
      else
            sch->lpm = 0;

      stsch (sch->schid, &sch->schib);

      CIO_MSG_EVENT(0, "cio_start: 'not oper' status for "
                  "subchannel 0.%x.%04x!\n", sch->schid.ssid,
                  sch->schid.sch_no);
      sprintf(dbf_text, "no%s", sch->dev.bus_id);
      CIO_TRACE_EVENT(0, dbf_text);
      CIO_HEX_EVENT(0, &sch->schib, sizeof (struct schib));

      return (sch->lpm ? -EACCES : -ENODEV);
}

int
cio_start_key (struct subchannel *sch,    /* subchannel structure */
             struct ccw1 * cpa,     /* logical channel prog addr */
             __u8 lpm,        /* logical path mask */
             __u8 key)                /* storage key */
{
      char dbf_txt[15];
      int ccode;

      CIO_TRACE_EVENT (4, "stIO");
      CIO_TRACE_EVENT (4, sch->dev.bus_id);

      /* sch is always under 2G. */
      sch->orb.intparm = (__u32)(unsigned long)sch;
      sch->orb.fmt = 1;

      sch->orb.pfch = sch->options.prefetch == 0;
      sch->orb.spnd = sch->options.suspend;
      sch->orb.ssic = sch->options.suspend && sch->options.inter;
      sch->orb.lpm = (lpm != 0) ? lpm : sch->lpm;
#ifdef CONFIG_64BIT
      /*
       * for 64 bit we always support 64 bit IDAWs with 4k page size only
       */
      sch->orb.c64 = 1;
      sch->orb.i2k = 0;
#endif
      sch->orb.key = key >> 4;
      /* issue "Start Subchannel" */
      sch->orb.cpa = (__u32) __pa (cpa);
      ccode = ssch (sch->schid, &sch->orb);

      /* process condition code */
      sprintf (dbf_txt, "ccode:%d", ccode);
      CIO_TRACE_EVENT (4, dbf_txt);

      switch (ccode) {
      case 0:
            /*
             * initialize device status information
             */
            sch->schib.scsw.actl |= SCSW_ACTL_START_PEND;
            return 0;
      case 1:           /* status pending */
      case 2:           /* busy */
            return -EBUSY;
      default:          /* device/path not operational */
            return cio_start_handle_notoper(sch, lpm);
      }
}

int
cio_start (struct subchannel *sch, struct ccw1 *cpa, __u8 lpm)
{
      return cio_start_key(sch, cpa, lpm, PAGE_DEFAULT_KEY);
}

/*
 * resume suspended I/O operation
 */
int
cio_resume (struct subchannel *sch)
{
      char dbf_txt[15];
      int ccode;

      CIO_TRACE_EVENT (4, "resIO");
      CIO_TRACE_EVENT (4, sch->dev.bus_id);

      ccode = rsch (sch->schid);

      sprintf (dbf_txt, "ccode:%d", ccode);
      CIO_TRACE_EVENT (4, dbf_txt);

      switch (ccode) {
      case 0:
            sch->schib.scsw.actl |= SCSW_ACTL_RESUME_PEND;
            return 0;
      case 1:
            return -EBUSY;
      case 2:
            return -EINVAL;
      default:
            /*
             * useless to wait for request completion
             *  as device is no longer operational !
             */
            return -ENODEV;
      }
}

/*
 * halt I/O operation
 */
int
cio_halt(struct subchannel *sch)
{
      char dbf_txt[15];
      int ccode;

      if (!sch)
            return -ENODEV;

      CIO_TRACE_EVENT (2, "haltIO");
      CIO_TRACE_EVENT (2, sch->dev.bus_id);

      /*
       * Issue "Halt subchannel" and process condition code
       */
      ccode = hsch (sch->schid);

      sprintf (dbf_txt, "ccode:%d", ccode);
      CIO_TRACE_EVENT (2, dbf_txt);

      switch (ccode) {
      case 0:
            sch->schib.scsw.actl |= SCSW_ACTL_HALT_PEND;
            return 0;
      case 1:           /* status pending */
      case 2:           /* busy */
            return -EBUSY;
      default:          /* device not operational */
            return -ENODEV;
      }
}

/*
 * Clear I/O operation
 */
int
cio_clear(struct subchannel *sch)
{
      char dbf_txt[15];
      int ccode;

      if (!sch)
            return -ENODEV;

      CIO_TRACE_EVENT (2, "clearIO");
      CIO_TRACE_EVENT (2, sch->dev.bus_id);

      /*
       * Issue "Clear subchannel" and process condition code
       */
      ccode = csch (sch->schid);

      sprintf (dbf_txt, "ccode:%d", ccode);
      CIO_TRACE_EVENT (2, dbf_txt);

      switch (ccode) {
      case 0:
            sch->schib.scsw.actl |= SCSW_ACTL_CLEAR_PEND;
            return 0;
      default:          /* device not operational */
            return -ENODEV;
      }
}

/*
 * Function: cio_cancel
 * Issues a "Cancel Subchannel" on the specified subchannel
 * Note: We don't need any fancy intparms and flags here
 *     since xsch is executed synchronously.
 * Only for common I/O internal use as for now.
 */
int
cio_cancel (struct subchannel *sch)
{
      char dbf_txt[15];
      int ccode;

      if (!sch)
            return -ENODEV;

      CIO_TRACE_EVENT (2, "cancelIO");
      CIO_TRACE_EVENT (2, sch->dev.bus_id);

      ccode = xsch (sch->schid);

      sprintf (dbf_txt, "ccode:%d", ccode);
      CIO_TRACE_EVENT (2, dbf_txt);

      switch (ccode) {
      case 0:           /* success */
            /* Update information in scsw. */
            stsch (sch->schid, &sch->schib);
            return 0;
      case 1:           /* status pending */
            return -EBUSY;
      case 2:           /* not applicable */
            return -EINVAL;
      default:    /* not oper */
            return -ENODEV;
      }
}

/*
 * Function: cio_modify
 * Issues a "Modify Subchannel" on the specified subchannel
 */
int
cio_modify (struct subchannel *sch)
{
      int ccode, retry, ret;

      ret = 0;
      for (retry = 0; retry < 5; retry++) {
            ccode = msch_err (sch->schid, &sch->schib);
            if (ccode < 0)    /* -EIO if msch gets a program check. */
                  return ccode;
            switch (ccode) {
            case 0: /* successfull */
                  return 0;
            case 1:     /* status pending */
                  return -EBUSY;
            case 2:     /* busy */
                  udelay (100);     /* allow for recovery */
                  ret = -EBUSY;
                  break;
            case 3:     /* not operational */
                  return -ENODEV;
            }
      }
      return ret;
}

/*
 * Enable subchannel.
 */
int
cio_enable_subchannel (struct subchannel *sch, unsigned int isc)
{
      char dbf_txt[15];
      int ccode;
      int retry;
      int ret;

      CIO_TRACE_EVENT (2, "ensch");
      CIO_TRACE_EVENT (2, sch->dev.bus_id);

      if (sch_is_pseudo_sch(sch))
            return -EINVAL;
      ccode = stsch (sch->schid, &sch->schib);
      if (ccode)
            return -ENODEV;

      for (retry = 5, ret = 0; retry > 0; retry--) {
            sch->schib.pmcw.ena = 1;
            sch->schib.pmcw.isc = isc;
            sch->schib.pmcw.intparm = (__u32)(unsigned long)sch;
            ret = cio_modify(sch);
            if (ret == -ENODEV)
                  break;
            if (ret == -EIO)
                  /*
                   * Got a program check in cio_modify. Try without
                   * the concurrent sense bit the next time.
                   */
                  sch->schib.pmcw.csense = 0;
            if (ret == 0) {
                  stsch (sch->schid, &sch->schib);
                  if (sch->schib.pmcw.ena)
                        break;
            }
            if (ret == -EBUSY) {
                  struct irb irb;
                  if (tsch(sch->schid, &irb) != 0)
                        break;
            }
      }
      sprintf (dbf_txt, "ret:%d", ret);
      CIO_TRACE_EVENT (2, dbf_txt);
      return ret;
}

/*
 * Disable subchannel.
 */
int
cio_disable_subchannel (struct subchannel *sch)
{
      char dbf_txt[15];
      int ccode;
      int retry;
      int ret;

      CIO_TRACE_EVENT (2, "dissch");
      CIO_TRACE_EVENT (2, sch->dev.bus_id);

      if (sch_is_pseudo_sch(sch))
            return 0;
      ccode = stsch (sch->schid, &sch->schib);
      if (ccode == 3)         /* Not operational. */
            return -ENODEV;

      if (sch->schib.scsw.actl != 0)
            /*
             * the disable function must not be called while there are
             *  requests pending for completion !
             */
            return -EBUSY;

      for (retry = 5, ret = 0; retry > 0; retry--) {
            sch->schib.pmcw.ena = 0;
            ret = cio_modify(sch);
            if (ret == -ENODEV)
                  break;
            if (ret == -EBUSY)
                  /*
                   * The subchannel is busy or status pending.
                   * We'll disable when the next interrupt was delivered
                   * via the state machine.
                   */
                  break;
            if (ret == 0) {
                  stsch (sch->schid, &sch->schib);
                  if (!sch->schib.pmcw.ena)
                        break;
            }
      }
      sprintf (dbf_txt, "ret:%d", ret);
      CIO_TRACE_EVENT (2, dbf_txt);
      return ret;
}

int cio_create_sch_lock(struct subchannel *sch)
{
      sch->lock = kmalloc(sizeof(spinlock_t), GFP_KERNEL);
      if (!sch->lock)
            return -ENOMEM;
      spin_lock_init(sch->lock);
      return 0;
}

/*
 * cio_validate_subchannel()
 *
 * Find out subchannel type and initialize struct subchannel.
 * Return codes:
 *   SUBCHANNEL_TYPE_IO for a normal io subchannel
 *   SUBCHANNEL_TYPE_CHSC for a chsc subchannel
 *   SUBCHANNEL_TYPE_MESSAGE for a messaging subchannel
 *   SUBCHANNEL_TYPE_ADM for a adm(?) subchannel
 *   -ENXIO for non-defined subchannels
 *   -ENODEV for subchannels with invalid device number or blacklisted devices
 */
int
cio_validate_subchannel (struct subchannel *sch, struct subchannel_id schid)
{
      char dbf_txt[15];
      int ccode;
      int err;

      sprintf (dbf_txt, "valsch%x", schid.sch_no);
      CIO_TRACE_EVENT (4, dbf_txt);

      /* Nuke all fields. */
      memset(sch, 0, sizeof(struct subchannel));

      sch->schid = schid;
      if (cio_is_console(schid)) {
            sch->lock = cio_get_console_lock();
      } else {
            err = cio_create_sch_lock(sch);
            if (err)
                  goto out;
      }
      mutex_init(&sch->reg_mutex);
      /* Set a name for the subchannel */
      snprintf (sch->dev.bus_id, BUS_ID_SIZE, "0.%x.%04x", schid.ssid,
              schid.sch_no);

      /*
       * The first subchannel that is not-operational (ccode==3)
       *  indicates that there aren't any more devices available.
       * If stsch gets an exception, it means the current subchannel set
       *  is not valid.
       */
      ccode = stsch_err (schid, &sch->schib);
      if (ccode) {
            err = (ccode == 3) ? -ENXIO : ccode;
            goto out;
      }
      /* Copy subchannel type from path management control word. */
      sch->st = sch->schib.pmcw.st;

      /*
       * ... just being curious we check for non I/O subchannels
       */
      if (sch->st != 0) {
            CIO_DEBUG(KERN_INFO, 0,
                    "cio: Subchannel 0.%x.%04x reports "
                    "non-I/O subchannel type %04X\n",
                    sch->schid.ssid, sch->schid.sch_no, sch->st);
            /* We stop here for non-io subchannels. */
            err = sch->st;
            goto out;
      }

      /* Initialization for io subchannels. */
      if (!sch->schib.pmcw.dnv) {
            /* io subchannel but device number is invalid. */
            err = -ENODEV;
            goto out;
      }
      /* Devno is valid. */
      if (is_blacklisted (sch->schid.ssid, sch->schib.pmcw.dev)) {
            /*
             * This device must not be known to Linux. So we simply
             * say that there is no device and return ENODEV.
             */
            CIO_MSG_EVENT(4, "Blacklisted device detected "
                        "at devno %04X, subchannel set %x\n",
                        sch->schib.pmcw.dev, sch->schid.ssid);
            err = -ENODEV;
            goto out;
      }
      if (cio_is_console(sch->schid))
            sch->opm = 0xff;
      else
            sch->opm = chp_get_sch_opm(sch);
      sch->lpm = sch->schib.pmcw.pam & sch->opm;

      CIO_DEBUG(KERN_INFO, 0,
              "cio: Detected device %04x on subchannel 0.%x.%04X"
              " - PIM = %02X, PAM = %02X, POM = %02X\n",
              sch->schib.pmcw.dev, sch->schid.ssid,
              sch->schid.sch_no, sch->schib.pmcw.pim,
              sch->schib.pmcw.pam, sch->schib.pmcw.pom);

      /*
       * We now have to initially ...
       *  ... set "interruption subclass"
       *  ... enable "concurrent sense"
       *  ... enable "multipath mode" if more than one
       *      CHPID is available. This is done regardless
       *      whether multiple paths are available for us.
       */
      sch->schib.pmcw.isc = 3;      /* could be smth. else */
      sch->schib.pmcw.csense = 1;   /* concurrent sense */
      sch->schib.pmcw.ena = 0;
      if ((sch->lpm & (sch->lpm - 1)) != 0)
            sch->schib.pmcw.mp = 1; /* multipath mode */
      /* clean up possible residual cmf stuff */
      sch->schib.pmcw.mme = 0;
      sch->schib.pmcw.mbfc = 0;
      sch->schib.pmcw.mbi = 0;
      sch->schib.mba = 0;
      return 0;
out:
      if (!cio_is_console(schid))
            kfree(sch->lock);
      sch->lock = NULL;
      return err;
}

/*
 * do_IRQ() handles all normal I/O device IRQ's (the special
 *        SMP cross-CPU interrupts have their own specific
 *        handlers).
 *
 */
void
do_IRQ (struct pt_regs *regs)
{
      struct tpi_info *tpi_info;
      struct subchannel *sch;
      struct irb *irb;
      struct pt_regs *old_regs;

      old_regs = set_irq_regs(regs);
      irq_enter();
      asm volatile ("mc 0,0");
      if (S390_lowcore.int_clock >= S390_lowcore.jiffy_timer)
            /**
             * Make sure that the i/o interrupt did not "overtake"
             * the last HZ timer interrupt.
             */
            account_ticks(S390_lowcore.int_clock);
      /*
       * Get interrupt information from lowcore
       */
      tpi_info = (struct tpi_info *) __LC_SUBCHANNEL_ID;
      irb = (struct irb *) __LC_IRB;
      do {
            kstat_cpu(smp_processor_id()).irqs[IO_INTERRUPT]++;
            /*
             * Non I/O-subchannel thin interrupts are processed differently
             */
            if (tpi_info->adapter_IO == 1 &&
                tpi_info->int_type == IO_INTERRUPT_TYPE) {
                  do_adapter_IO();
                  continue;
            }
            sch = (struct subchannel *)(unsigned long)tpi_info->intparm;
            if (sch)
                  spin_lock(sch->lock);
            /* Store interrupt response block to lowcore. */
            if (tsch (tpi_info->schid, irb) == 0 && sch) {
                  /* Keep subchannel information word up to date. */
                  memcpy (&sch->schib.scsw, &irb->scsw,
                        sizeof (irb->scsw));
                  /* Call interrupt handler if there is one. */
                  if (sch->driver && sch->driver->irq)
                        sch->driver->irq(&sch->dev);
            }
            if (sch)
                  spin_unlock(sch->lock);
            /*
             * Are more interrupts pending?
             * If so, the tpi instruction will update the lowcore
             * to hold the info for the next interrupt.
             * We don't do this for VM because a tpi drops the cpu
             * out of the sie which costs more cycles than it saves.
             */
      } while (!MACHINE_IS_VM && tpi (NULL) != 0);
      irq_exit();
      set_irq_regs(old_regs);
}

#ifdef CONFIG_CCW_CONSOLE
static struct subchannel console_subchannel;
static int console_subchannel_in_use;

/*
 * busy wait for the next interrupt on the console
 */
void
wait_cons_dev (void)
{
      unsigned long cr6      __attribute__ ((aligned (8)));
      unsigned long save_cr6 __attribute__ ((aligned (8)));

      /* 
       * before entering the spinlock we may already have
       * processed the interrupt on a different CPU...
       */
      if (!console_subchannel_in_use)
            return;

      /* disable all but isc 7 (console device) */
      __ctl_store (save_cr6, 6, 6);
      cr6 = 0x01000000;
      __ctl_load (cr6, 6, 6);

      do {
            spin_unlock(console_subchannel.lock);
            if (!cio_tpi())
                  cpu_relax();
            spin_lock(console_subchannel.lock);
      } while (console_subchannel.schib.scsw.actl != 0);
      /*
       * restore previous isc value
       */
      __ctl_load (save_cr6, 6, 6);
}

static int
cio_test_for_console(struct subchannel_id schid, void *data)
{
      if (stsch_err(schid, &console_subchannel.schib) != 0)
            return -ENXIO;
      if (console_subchannel.schib.pmcw.dnv &&
          console_subchannel.schib.pmcw.dev ==
          console_devno) {
            console_irq = schid.sch_no;
            return 1; /* found */
      }
      return 0;
}


static int
cio_get_console_sch_no(void)
{
      struct subchannel_id schid;
      
      init_subchannel_id(&schid);
      if (console_irq != -1) {
            /* VM provided us with the irq number of the console. */
            schid.sch_no = console_irq;
            if (stsch(schid, &console_subchannel.schib) != 0 ||
                !console_subchannel.schib.pmcw.dnv)
                  return -1;
            console_devno = console_subchannel.schib.pmcw.dev;
      } else if (console_devno != -1) {
            /* At least the console device number is known. */
            for_each_subchannel(cio_test_for_console, NULL);
            if (console_irq == -1)
                  return -1;
      } else {
            /* unlike in 2.4, we cannot autoprobe here, since
             * the channel subsystem is not fully initialized.
             * With some luck, the HWC console can take over */
            printk(KERN_WARNING "cio: No ccw console found!\n");
            return -1;
      }
      return console_irq;
}

struct subchannel *
cio_probe_console(void)
{
      int sch_no, ret;
      struct subchannel_id schid;

      if (xchg(&console_subchannel_in_use, 1) != 0)
            return ERR_PTR(-EBUSY);
      sch_no = cio_get_console_sch_no();
      if (sch_no == -1) {
            console_subchannel_in_use = 0;
            return ERR_PTR(-ENODEV);
      }
      memset(&console_subchannel, 0, sizeof(struct subchannel));
      init_subchannel_id(&schid);
      schid.sch_no = sch_no;
      ret = cio_validate_subchannel(&console_subchannel, schid);
      if (ret) {
            console_subchannel_in_use = 0;
            return ERR_PTR(-ENODEV);
      }

      /*
       * enable console I/O-interrupt subclass 7
       */
      ctl_set_bit(6, 24);
      console_subchannel.schib.pmcw.isc = 7;
      console_subchannel.schib.pmcw.intparm =
            (__u32)(unsigned long)&console_subchannel;
      ret = cio_modify(&console_subchannel);
      if (ret) {
            console_subchannel_in_use = 0;
            return ERR_PTR(ret);
      }
      return &console_subchannel;
}

void
cio_release_console(void)
{
      console_subchannel.schib.pmcw.intparm = 0;
      cio_modify(&console_subchannel);
      ctl_clear_bit(6, 24);
      console_subchannel_in_use = 0;
}

/* Bah... hack to catch console special sausages. */
int
cio_is_console(struct subchannel_id schid)
{
      if (!console_subchannel_in_use)
            return 0;
      return schid_equal(&schid, &console_subchannel.schid);
}

struct subchannel *
cio_get_console_subchannel(void)
{
      if (!console_subchannel_in_use)
            return NULL;
      return &console_subchannel;
}

#endif
static int
__disable_subchannel_easy(struct subchannel_id schid, struct schib *schib)
{
      int retry, cc;

      cc = 0;
      for (retry=0;retry<3;retry++) {
            schib->pmcw.ena = 0;
            cc = msch(schid, schib);
            if (cc)
                  return (cc==3?-ENODEV:-EBUSY);
            stsch(schid, schib);
            if (!schib->pmcw.ena)
                  return 0;
      }
      return -EBUSY; /* uhm... */
}

/* we can't use the normal udelay here, since it enables external interrupts */

static void udelay_reset(unsigned long usecs)
{
      uint64_t start_cc, end_cc;

      asm volatile ("STCK %0" : "=m" (start_cc));
      do {
            cpu_relax();
            asm volatile ("STCK %0" : "=m" (end_cc));
      } while (((end_cc - start_cc)/4096) < usecs);
}

static int
__clear_subchannel_easy(struct subchannel_id schid)
{
      int retry;

      if (csch(schid))
            return -ENODEV;
      for (retry=0;retry<20;retry++) {
            struct tpi_info ti;

            if (tpi(&ti)) {
                  tsch(ti.schid, (struct irb *)__LC_IRB);
                  if (schid_equal(&ti.schid, &schid))
                        return 0;
            }
            udelay_reset(100);
      }
      return -EBUSY;
}

static int pgm_check_occured;

static void cio_reset_pgm_check_handler(void)
{
      pgm_check_occured = 1;
}

static int stsch_reset(struct subchannel_id schid, volatile struct schib *addr)
{
      int rc;

      pgm_check_occured = 0;
      s390_base_pgm_handler_fn = cio_reset_pgm_check_handler;
      rc = stsch(schid, addr);
      s390_base_pgm_handler_fn = NULL;

      /* The program check handler could have changed pgm_check_occured. */
      barrier();

      if (pgm_check_occured)
            return -EIO;
      else
            return rc;
}

static int __shutdown_subchannel_easy(struct subchannel_id schid, void *data)
{
      struct schib schib;

      if (stsch_reset(schid, &schib))
            return -ENXIO;
      if (!schib.pmcw.ena)
            return 0;
      switch(__disable_subchannel_easy(schid, &schib)) {
      case 0:
      case -ENODEV:
            break;
      default: /* -EBUSY */
            if (__clear_subchannel_easy(schid))
                  break; /* give up... */
            stsch(schid, &schib);
            __disable_subchannel_easy(schid, &schib);
      }
      return 0;
}

static atomic_t chpid_reset_count;

static void s390_reset_chpids_mcck_handler(void)
{
      struct crw crw;
      struct mci *mci;

      /* Check for pending channel report word. */
      mci = (struct mci *)&S390_lowcore.mcck_interruption_code;
      if (!mci->cp)
            return;
      /* Process channel report words. */
      while (stcrw(&crw) == 0) {
            /* Check for responses to RCHP. */
            if (crw.slct && crw.rsc == CRW_RSC_CPATH)
                  atomic_dec(&chpid_reset_count);
      }
}

#define RCHP_TIMEOUT (30 * USEC_PER_SEC)
static void css_reset(void)
{
      int i, ret;
      unsigned long long timeout;
      struct chp_id chpid;

      /* Reset subchannels. */
      for_each_subchannel(__shutdown_subchannel_easy,  NULL);
      /* Reset channel paths. */
      s390_base_mcck_handler_fn = s390_reset_chpids_mcck_handler;
      /* Enable channel report machine checks. */
      __ctl_set_bit(14, 28);
      /* Temporarily reenable machine checks. */
      local_mcck_enable();
      chp_id_init(&chpid);
      for (i = 0; i <= __MAX_CHPID; i++) {
            chpid.id = i;
            ret = rchp(chpid);
            if ((ret == 0) || (ret == 2))
                  /*
                   * rchp either succeeded, or another rchp is already
                   * in progress. In either case, we'll get a crw.
                   */
                  atomic_inc(&chpid_reset_count);
      }
      /* Wait for machine check for all channel paths. */
      timeout = get_clock() + (RCHP_TIMEOUT << 12);
      while (atomic_read(&chpid_reset_count) != 0) {
            if (get_clock() > timeout)
                  break;
            cpu_relax();
      }
      /* Disable machine checks again. */
      local_mcck_disable();
      /* Disable channel report machine checks. */
      __ctl_clear_bit(14, 28);
      s390_base_mcck_handler_fn = NULL;
}

static struct reset_call css_reset_call = {
      .fn = css_reset,
};

static int __init init_css_reset_call(void)
{
      atomic_set(&chpid_reset_count, 0);
      register_reset_call(&css_reset_call);
      return 0;
}

arch_initcall(init_css_reset_call);

struct sch_match_id {
      struct subchannel_id schid;
      struct ccw_dev_id devid;
      int rc;
};

static int __reipl_subchannel_match(struct subchannel_id schid, void *data)
{
      struct schib schib;
      struct sch_match_id *match_id = data;

      if (stsch_reset(schid, &schib))
            return -ENXIO;
      if (schib.pmcw.dnv &&
          (schib.pmcw.dev == match_id->devid.devno) &&
          (schid.ssid == match_id->devid.ssid)) {
            match_id->schid = schid;
            match_id->rc = 0;
            return 1;
      }
      return 0;
}

static int reipl_find_schid(struct ccw_dev_id *devid,
                      struct subchannel_id *schid)
{
      struct sch_match_id match_id;

      match_id.devid = *devid;
      match_id.rc = -ENODEV;
      for_each_subchannel(__reipl_subchannel_match, &match_id);
      if (match_id.rc == 0)
            *schid = match_id.schid;
      return match_id.rc;
}

extern void do_reipl_asm(__u32 schid);

/* Make sure all subchannels are quiet before we re-ipl an lpar. */
void reipl_ccw_dev(struct ccw_dev_id *devid)
{
      struct subchannel_id schid;

      s390_reset_system();
      if (reipl_find_schid(devid, &schid) != 0)
            panic("IPL Device not found\n");
      do_reipl_asm(*((__u32*)&schid));
}

int __init cio_get_iplinfo(struct cio_iplinfo *iplinfo)
{
      struct subchannel_id schid;
      struct schib schib;

      schid = *(struct subchannel_id *)__LC_SUBCHANNEL_ID;
      if (!schid.one)
            return -ENODEV;
      if (stsch(schid, &schib))
            return -ENODEV;
      if (!schib.pmcw.dnv)
            return -ENODEV;
      iplinfo->devno = schib.pmcw.dev;
      iplinfo->is_qdio = schib.pmcw.qf;
      return 0;
}

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