// SPDX-License-Identifier: GPL-2.0
/*
 * finite state machine for device handling
 *
 *    Copyright IBM Corp. 2002, 2008
 *    Author(s): Cornelia Huck (cornelia.huck@de.ibm.com)
 *   Martin Schwidefsky (schwidefsky@de.ibm.com)
 */

#include <linux/export.h>
#include <linux/module.h>
#include <linux/init.h>
#include <linux/io.h>
#include <linux/jiffies.h>
#include <linux/string.h>

#include <asm/ccwdev.h>
#include <asm/cio.h>
#include <asm/chpid.h>

#include "cio.h"
#include "cio_debug.h"
#include "css.h"
#include "device.h"
#include "chsc.h"
#include "ioasm.h"
#include "chp.h"

static int timeout_log_enabled;

static int __init ccw_timeout_log_setup(char *unused)
{
 timeout_log_enabled = 1;
 return 1;
}

__setup("ccw_timeout_log", ccw_timeout_log_setup);

static void ccw_timeout_log(struct ccw_device *cdev)
{
 struct schib schib;
 struct subchannel *sch;
 struct io_subchannel_private *private;
 union orb *orb;
 int cc;

 sch = to_subchannel(cdev->dev.parent);
 private = to_io_private(sch);
 orb = &private->orb;
 cc = stsch(sch->schid, &schib);

 printk(KERN_WARNING "cio: ccw device timeout occurred at %lx, "
        "device information:\n", get_tod_clock());
 printk(KERN_WARNING "cio: orb:\n");
 print_hex_dump(KERN_WARNING, "cio:  ", DUMP_PREFIX_NONE, 16, 1,
         orb, sizeof(*orb), 0);
 printk(KERN_WARNING "cio: ccw device bus id: %s\n",
        dev_name(&cdev->dev));
 printk(KERN_WARNING "cio: subchannel bus id: %s\n",
        dev_name(&sch->dev));
 printk(KERN_WARNING "cio: subchannel lpm: %02x, opm: %02x, "
        "vpm: %02x\n", sch->lpm, sch->opm, sch->vpm);

 if (orb->tm.b) {
  printk(KERN_WARNING "cio: orb indicates transport mode\n");
  printk(KERN_WARNING "cio: last tcw:\n");
  print_hex_dump(KERN_WARNING, "cio:  ", DUMP_PREFIX_NONE, 16, 1,
          dma32_to_virt(orb->tm.tcw),
          sizeof(struct tcw), 0);
 } else {
  printk(KERN_WARNING "cio: orb indicates command mode\n");
  if (dma32_to_virt(orb->cmd.cpa) ==
      &private->dma_area->sense_ccw ||
      dma32_to_virt(orb->cmd.cpa) ==
      cdev->private->dma_area->iccws)
   printk(KERN_WARNING "cio: last channel program "
          "(intern):\n");
  else
   printk(KERN_WARNING "cio: last channel program:\n");

  print_hex_dump(KERN_WARNING, "cio:  ", DUMP_PREFIX_NONE, 16, 1,
          dma32_to_virt(orb->cmd.cpa),
          sizeof(struct ccw1), 0);
 }
 printk(KERN_WARNING "cio: ccw device state: %d\n",
        cdev->private->state);
 printk(KERN_WARNING "cio: store subchannel returned: cc=%d\n", cc);
 printk(KERN_WARNING "cio: schib:\n");
 print_hex_dump(KERN_WARNING, "cio:  ", DUMP_PREFIX_NONE, 16, 1,
         &schib, sizeof(schib), 0);
 printk(KERN_WARNING "cio: ccw device flags:\n");
 print_hex_dump(KERN_WARNING, "cio:  ", DUMP_PREFIX_NONE, 16, 1,
         &cdev->private->flags, sizeof(cdev->private->flags), 0);
}

/*
 * Timeout function. It just triggers a DEV_EVENT_TIMEOUT.
 */
void
ccw_device_timeout(struct timer_list *t)
{
 struct ccw_device_private *priv = timer_container_of(priv, t, timer);
 struct ccw_device *cdev = priv->cdev;

 spin_lock_irq(cdev->ccwlock);
 if (timeout_log_enabled)
  ccw_timeout_log(cdev);
 dev_fsm_event(cdev, DEV_EVENT_TIMEOUT);
 spin_unlock_irq(cdev->ccwlock);
}

/*
 * Set timeout
 */
void
ccw_device_set_timeout(struct ccw_device *cdev, int expires)
{
 if (expires == 0)
  timer_delete(&cdev->private->timer);
 else
  mod_timer(&cdev->private->timer, jiffies + expires);
}

int
ccw_device_cancel_halt_clear(struct ccw_device *cdev)
{
 struct subchannel *sch;
 int ret;

 sch = to_subchannel(cdev->dev.parent);
 ret = cio_cancel_halt_clear(sch, &cdev->private->iretry);

 if (ret == -EIO)
  CIO_MSG_EVENT(0, "0.%x.%04x: could not stop I/O\n",
         cdev->private->dev_id.ssid,
         cdev->private->dev_id.devno);

 return ret;
}

void ccw_device_update_sense_data(struct ccw_device *cdev)
{
 memset(&cdev->id, 0, sizeof(cdev->id));
 cdev->id.cu_type = cdev->private->dma_area->senseid.cu_type;
 cdev->id.cu_model = cdev->private->dma_area->senseid.cu_model;
 cdev->id.dev_type = cdev->private->dma_area->senseid.dev_type;
 cdev->id.dev_model = cdev->private->dma_area->senseid.dev_model;
}

int ccw_device_test_sense_data(struct ccw_device *cdev)
{
 return cdev->id.cu_type ==
  cdev->private->dma_area->senseid.cu_type &&
  cdev->id.cu_model ==
  cdev->private->dma_area->senseid.cu_model &&
  cdev->id.dev_type ==
  cdev->private->dma_area->senseid.dev_type &&
  cdev->id.dev_model ==
  cdev->private->dma_area->senseid.dev_model;
}

/*
 * The machine won't give us any notification by machine check if a chpid has
 * been varied online on the SE so we have to find out by magic (i. e. driving
 * the channel subsystem to device selection and updating our path masks).
 */
static void
__recover_lost_chpids(struct subchannel *sch, int old_lpm)
{
 int mask, i;
 struct chp_id chpid;

 chp_id_init(&chpid);
 for (i = 0; i<8; i++) {
  mask = 0x80 >> i;
  if (!(sch->lpm & mask))
   continue;
  if (old_lpm & mask)
   continue;
  chpid.id = sch->schib.pmcw.chpid[i];
  if (!chp_is_registered(chpid))
   css_schedule_eval_all();
 }
}

/*
 * Stop device recognition.
 */
static void
ccw_device_recog_done(struct ccw_device *cdev, int state)
{
 struct subchannel *sch;
 int old_lpm;

 sch = to_subchannel(cdev->dev.parent);

 if (cio_disable_subchannel(sch))
  state = DEV_STATE_NOT_OPER;
 /*
  * Now that we tried recognition, we have performed device selection
  * through ssch() and the path information is up to date.
 */
 old_lpm = sch->lpm;

 /* Check since device may again have become not operational. */
 if (cio_update_schib(sch))
  state = DEV_STATE_NOT_OPER;
 else
  sch->lpm = sch->schib.pmcw.pam & sch->opm;

 if (cdev->private->state == DEV_STATE_DISCONNECTED_SENSE_ID)
  /* Force reprobe on all chpids. */
  old_lpm = 0;
 if (sch->lpm != old_lpm)
  __recover_lost_chpids(sch, old_lpm);
 if (cdev->private->state == DEV_STATE_DISCONNECTED_SENSE_ID &&
     (state == DEV_STATE_NOT_OPER || state == DEV_STATE_BOXED)) {
  cdev->private->flags.recog_done = 1;
  cdev->private->state = DEV_STATE_DISCONNECTED;
  wake_up(&cdev->private->wait_q);
  return;
 }
 switch (state) {
 case DEV_STATE_NOT_OPER:
  break;
 case DEV_STATE_OFFLINE:
  if (!cdev->online) {
   ccw_device_update_sense_data(cdev);
   break;
  }
  cdev->private->state = DEV_STATE_OFFLINE;
  cdev->private->flags.recog_done = 1;
  if (ccw_device_test_sense_data(cdev)) {
   cdev->private->flags.donotify = 1;
   ccw_device_online(cdev);
   wake_up(&cdev->private->wait_q);
  } else {
   ccw_device_update_sense_data(cdev);
   ccw_device_sched_todo(cdev, CDEV_TODO_REBIND);
  }
  return;
 case DEV_STATE_BOXED:
  if (cdev->id.cu_type != 0) { /* device was recognized before */
   cdev->private->flags.recog_done = 1;
   cdev->private->state = DEV_STATE_BOXED;
   wake_up(&cdev->private->wait_q);
   return;
  }
  break;
 }
 cdev->private->state = state;
 io_subchannel_recog_done(cdev);
 wake_up(&cdev->private->wait_q);
}

/*
 * Function called from device_id.c after sense id has completed.
 */
void
ccw_device_sense_id_done(struct ccw_device *cdev, int err)
{
 switch (err) {
 case 0:
  ccw_device_recog_done(cdev, DEV_STATE_OFFLINE);
  break;
 case -ETIME:  /* Sense id stopped by timeout. */
  ccw_device_recog_done(cdev, DEV_STATE_BOXED);
  break;
 default:
  ccw_device_recog_done(cdev, DEV_STATE_NOT_OPER);
  break;
 }
}

/**
  * ccw_device_notify() - inform the device's driver about an event
  * @cdev: device for which an event occurred
  * @event: event that occurred
  *
  * Returns:
  *   -%EINVAL if the device is offline or has no driver.
  *   -%EOPNOTSUPP if the device's driver has no notifier registered.
  *   %NOTIFY_OK if the driver wants to keep the device.
  *   %NOTIFY_BAD if the driver doesn't want to keep the device.
  */
int ccw_device_notify(struct ccw_device *cdev, int event)
{
 int ret = -EINVAL;

 if (!cdev->drv)
  goto out;
 if (!cdev->online)
  goto out;
 CIO_MSG_EVENT(2, "notify called for 0.%x.%04x, event=%d\n",
        cdev->private->dev_id.ssid, cdev->private->dev_id.devno,
        event);
 if (!cdev->drv->notify) {
  ret = -EOPNOTSUPP;
  goto out;
 }
 if (cdev->drv->notify(cdev, event))
  ret = NOTIFY_OK;
 else
  ret = NOTIFY_BAD;
out:
 return ret;
}

static void ccw_device_oper_notify(struct ccw_device *cdev)
{
 struct subchannel *sch = to_subchannel(cdev->dev.parent);

 if (ccw_device_notify(cdev, CIO_OPER) == NOTIFY_OK) {
  /* Re-enable channel measurements, if needed. */
  ccw_device_sched_todo(cdev, CDEV_TODO_ENABLE_CMF);
  /* Save indication for new paths. */
  cdev->private->path_new_mask = sch->vpm;
  return;
 }
 /* Driver doesn't want device back. */
 ccw_device_set_notoper(cdev);
 ccw_device_sched_todo(cdev, CDEV_TODO_REBIND);
}

/*
 * Finished with online/offline processing.
 */
static void
ccw_device_done(struct ccw_device *cdev, int state)
{
 struct subchannel *sch;

 sch = to_subchannel(cdev->dev.parent);

 ccw_device_set_timeout(cdev, 0);

 if (state != DEV_STATE_ONLINE)
  cio_disable_subchannel(sch);

 /* Reset device status. */
 memset(&cdev->private->dma_area->irb, 0, sizeof(struct irb));

 cdev->private->state = state;

 switch (state) {
 case DEV_STATE_BOXED:
  CIO_MSG_EVENT(0, "Boxed device %04x on subchannel %04x\n",
         cdev->private->dev_id.devno, sch->schid.sch_no);
  if (cdev->online &&
      ccw_device_notify(cdev, CIO_BOXED) != NOTIFY_OK)
   ccw_device_sched_todo(cdev, CDEV_TODO_UNREG);
  cdev->private->flags.donotify = 0;
  break;
 case DEV_STATE_NOT_OPER:
  CIO_MSG_EVENT(0, "Device %04x gone on subchannel %04x\n",
         cdev->private->dev_id.devno, sch->schid.sch_no);
  if (ccw_device_notify(cdev, CIO_GONE) != NOTIFY_OK)
   ccw_device_sched_todo(cdev, CDEV_TODO_UNREG);
  else
   ccw_device_set_disconnected(cdev);
  cdev->private->flags.donotify = 0;
  break;
 case DEV_STATE_DISCONNECTED:
  CIO_MSG_EVENT(0, "Disconnected device %04x on subchannel "
         "%04x\n", cdev->private->dev_id.devno,
         sch->schid.sch_no);
  if (ccw_device_notify(cdev, CIO_NO_PATH) != NOTIFY_OK) {
   cdev->private->state = DEV_STATE_NOT_OPER;
   ccw_device_sched_todo(cdev, CDEV_TODO_UNREG);
  } else
   ccw_device_set_disconnected(cdev);
  cdev->private->flags.donotify = 0;
  break;
 default:
  break;
 }

 if (cdev->private->flags.donotify) {
  cdev->private->flags.donotify = 0;
  ccw_device_oper_notify(cdev);
 }
 wake_up(&cdev->private->wait_q);
}

/*
 * Start device recognition.
 */
void ccw_device_recognition(struct ccw_device *cdev)
{
 struct subchannel *sch = to_subchannel(cdev->dev.parent);

 /*
  * We used to start here with a sense pgid to find out whether a device
  * is locked by someone else. Unfortunately, the sense pgid command
  * code has other meanings on devices predating the path grouping
  * algorithm, so we start with sense id and box the device after an
  * timeout (or if sense pgid during path verification detects the device
  * is locked, as may happen on newer devices).
 */
 cdev->private->flags.recog_done = 0;
 cdev->private->state = DEV_STATE_SENSE_ID;
 if (cio_enable_subchannel(sch, (u32)virt_to_phys(sch))) {
  ccw_device_recog_done(cdev, DEV_STATE_NOT_OPER);
  return;
 }
 ccw_device_sense_id_start(cdev);
}

/*
 * Handle events for states that use the ccw request infrastructure.
 */
static void ccw_device_request_event(struct ccw_device *cdev, enum dev_event e)
{
 switch (e) {
 case DEV_EVENT_NOTOPER:
  ccw_request_notoper(cdev);
  break;
 case DEV_EVENT_INTERRUPT:
  ccw_request_handler(cdev);
  break;
 case DEV_EVENT_TIMEOUT:
  ccw_request_timeout(cdev);
  break;
 default:
  break;
 }
}

static void ccw_device_report_path_events(struct ccw_device *cdev)
{
 struct subchannel *sch = to_subchannel(cdev->dev.parent);
 int path_event[8];
 int chp, mask;

 for (chp = 0, mask = 0x80; chp < 8; chp++, mask >>= 1) {
  path_event[chp] = PE_NONE;
  if (mask & cdev->private->path_gone_mask & ~(sch->vpm))
   path_event[chp] |= PE_PATH_GONE;
  if (mask & cdev->private->path_new_mask & sch->vpm)
   path_event[chp] |= PE_PATH_AVAILABLE;
  if (mask & cdev->private->pgid_reset_mask & sch->vpm)
   path_event[chp] |= PE_PATHGROUP_ESTABLISHED;
 }
 if (cdev->online && cdev->drv->path_event)
  cdev->drv->path_event(cdev, path_event);
}

static void ccw_device_reset_path_events(struct ccw_device *cdev)
{
 cdev->private->path_gone_mask = 0;
 cdev->private->path_new_mask = 0;
 cdev->private->pgid_reset_mask = 0;
}

static void create_fake_irb(struct irb *irb, int type)
{
 memset(irb, 0, sizeof(*irb));
 if (type == FAKE_CMD_IRB) {
  struct cmd_scsw *scsw = &irb->scsw.cmd;
  scsw->cc = 1;
  scsw->fctl = SCSW_FCTL_START_FUNC;
  scsw->actl = SCSW_ACTL_START_PEND;
  scsw->stctl = SCSW_STCTL_STATUS_PEND;
 } else if (type == FAKE_TM_IRB) {
  struct tm_scsw *scsw = &irb->scsw.tm;
  scsw->x = 1;
  scsw->cc = 1;
  scsw->fctl = SCSW_FCTL_START_FUNC;
  scsw->actl = SCSW_ACTL_START_PEND;
  scsw->stctl = SCSW_STCTL_STATUS_PEND;
 }
}

static void ccw_device_handle_broken_paths(struct ccw_device *cdev)
{
 struct subchannel *sch = to_subchannel(cdev->dev.parent);
 u8 broken_paths = (sch->schib.pmcw.pam & sch->opm) ^ sch->vpm;

 if (broken_paths && (cdev->private->path_broken_mask != broken_paths))
  ccw_device_schedule_recovery();

 cdev->private->path_broken_mask = broken_paths;
}

void ccw_device_verify_done(struct ccw_device *cdev, int err)
{
 struct subchannel *sch;

 sch = to_subchannel(cdev->dev.parent);
 /* Update schib - pom may have changed. */
 if (cio_update_schib(sch)) {
  err = -ENODEV;
  goto callback;
 }
 /* Update lpm with verified path mask. */
 sch->lpm = sch->vpm;
 /* Repeat path verification? */
 if (cdev->private->flags.doverify) {
  ccw_device_verify_start(cdev);
  return;
 }
callback:
 switch (err) {
 case 0:
  ccw_device_done(cdev, DEV_STATE_ONLINE);
  /* Deliver fake irb to device driver, if needed. */
  if (cdev->private->flags.fake_irb) {
   CIO_MSG_EVENT(2, "fakeirb: deliver device 0.%x.%04x intparm %lx type=%d\n",
          cdev->private->dev_id.ssid,
          cdev->private->dev_id.devno,
          cdev->private->intparm,
          cdev->private->flags.fake_irb);
   create_fake_irb(&cdev->private->dma_area->irb,
     cdev->private->flags.fake_irb);
   cdev->private->flags.fake_irb = 0;
   if (cdev->handler)
    cdev->handler(cdev, cdev->private->intparm,
           &cdev->private->dma_area->irb);
   memset(&cdev->private->dma_area->irb, 0,
          sizeof(struct irb));
  }
  ccw_device_report_path_events(cdev);
  ccw_device_handle_broken_paths(cdev);
  break;
 case -ETIME:
 case -EUSERS:
  /* Reset oper notify indication after verify error. */
  cdev->private->flags.donotify = 0;
  ccw_device_done(cdev, DEV_STATE_BOXED);
  break;
 case -EACCES:
  /* Reset oper notify indication after verify error. */
  cdev->private->flags.donotify = 0;
  ccw_device_done(cdev, DEV_STATE_DISCONNECTED);
  break;
 default:
  /* Reset oper notify indication after verify error. */
  cdev->private->flags.donotify = 0;
  ccw_device_done(cdev, DEV_STATE_NOT_OPER);
  break;
 }
 ccw_device_reset_path_events(cdev);
}

/*
 * Get device online.
 */
int
ccw_device_online(struct ccw_device *cdev)
{
 struct subchannel *sch;
 int ret;

 if ((cdev->private->state != DEV_STATE_OFFLINE) &&
     (cdev->private->state != DEV_STATE_BOXED))
  return -EINVAL;
 sch = to_subchannel(cdev->dev.parent);
 ret = cio_enable_subchannel(sch, (u32)virt_to_phys(sch));
 if (ret != 0) {
  /* Couldn't enable the subchannel for i/o. Sick device. */
  if (ret == -ENODEV)
   dev_fsm_event(cdev, DEV_EVENT_NOTOPER);
  return ret;
 }
 /* Start initial path verification. */
 cdev->private->state = DEV_STATE_VERIFY;
 ccw_device_verify_start(cdev);
 return 0;
}

void
ccw_device_disband_done(struct ccw_device *cdev, int err)
{
 switch (err) {
 case 0:
  ccw_device_done(cdev, DEV_STATE_OFFLINE);
  break;
 case -ETIME:
  ccw_device_done(cdev, DEV_STATE_BOXED);
  break;
 default:
  cdev->private->flags.donotify = 0;
  ccw_device_done(cdev, DEV_STATE_NOT_OPER);
  break;
 }
}

/*
 * Shutdown device.
 */
int
ccw_device_offline(struct ccw_device *cdev)
{
 struct subchannel *sch;

 /* Allow ccw_device_offline while disconnected. */
 if (cdev->private->state == DEV_STATE_DISCONNECTED ||
     cdev->private->state == DEV_STATE_NOT_OPER) {
  cdev->private->flags.donotify = 0;
  ccw_device_done(cdev, DEV_STATE_NOT_OPER);
  return 0;
 }
 if (cdev->private->state == DEV_STATE_BOXED) {
  ccw_device_done(cdev, DEV_STATE_BOXED);
  return 0;
 }
 if (ccw_device_is_orphan(cdev)) {
  ccw_device_done(cdev, DEV_STATE_OFFLINE);
  return 0;
 }
 sch = to_subchannel(cdev->dev.parent);
 if (cio_update_schib(sch))
  return -ENODEV;
 if (scsw_actl(&sch->schib.scsw) != 0)
  return -EBUSY;
 if (cdev->private->state != DEV_STATE_ONLINE)
  return -EINVAL;
 /* Are we doing path grouping? */
 if (!cdev->private->flags.pgroup) {
  /* No, set state offline immediately. */
  ccw_device_done(cdev, DEV_STATE_OFFLINE);
  return 0;
 }
 /* Start Set Path Group commands. */
 cdev->private->state = DEV_STATE_DISBAND_PGID;
 ccw_device_disband_start(cdev);
 return 0;
}

/*
 * Handle not operational event in non-special state.
 */
static void ccw_device_generic_notoper(struct ccw_device *cdev,
           enum dev_event dev_event)
{
 if (ccw_device_notify(cdev, CIO_GONE) != NOTIFY_OK)
  ccw_device_sched_todo(cdev, CDEV_TODO_UNREG);
 else
  ccw_device_set_disconnected(cdev);
}

/*
 * Handle path verification event in offline state.
 */
static void ccw_device_offline_verify(struct ccw_device *cdev,
          enum dev_event dev_event)
{
 struct subchannel *sch = to_subchannel(cdev->dev.parent);

 css_schedule_eval(sch->schid);
}

/*
 * Handle path verification event.
 */
static void
ccw_device_online_verify(struct ccw_device *cdev, enum dev_event dev_event)
{
 struct subchannel *sch;

 if (cdev->private->state == DEV_STATE_W4SENSE) {
  cdev->private->flags.doverify = 1;
  return;
 }
 sch = to_subchannel(cdev->dev.parent);
 /*
  * Since we might not just be coming from an interrupt from the
  * subchannel we have to update the schib.
 */
 if (cio_update_schib(sch)) {
  ccw_device_verify_done(cdev, -ENODEV);
  return;
 }

 if (scsw_actl(&sch->schib.scsw) != 0 ||
     (scsw_stctl(&sch->schib.scsw) & SCSW_STCTL_STATUS_PEND) ||
     (scsw_stctl(&cdev->private->dma_area->irb.scsw) &
      SCSW_STCTL_STATUS_PEND)) {
  /*
   * No final status yet or final status not yet delivered
   * to the device driver. Can't do path verification now,
   * delay until final status was delivered.
 */
  cdev->private->flags.doverify = 1;
  return;
 }
 /* Device is idle, we can do the path verification. */
 cdev->private->state = DEV_STATE_VERIFY;
 ccw_device_verify_start(cdev);
}

/*
 * Handle path verification event in boxed state.
 */
static void ccw_device_boxed_verify(struct ccw_device *cdev,
        enum dev_event dev_event)
{
 struct subchannel *sch = to_subchannel(cdev->dev.parent);

 if (cdev->online) {
  if (cio_enable_subchannel(sch, (u32)virt_to_phys(sch)))
   ccw_device_done(cdev, DEV_STATE_NOT_OPER);
  else
   ccw_device_online_verify(cdev, dev_event);
 } else
  css_schedule_eval(sch->schid);
}

/*
 * Pass interrupt to device driver.
 */
static int ccw_device_call_handler(struct ccw_device *cdev)
{
 unsigned int stctl;
 int ending_status;

 /*
  * we allow for the device action handler if .
  *  - we received ending status
  *  - the action handler requested to see all interrupts
  *  - we received an intermediate status
  *  - fast notification was requested (primary status)
  *  - unsolicited interrupts
 */
 stctl = scsw_stctl(&cdev->private->dma_area->irb.scsw);
 ending_status = (stctl & SCSW_STCTL_SEC_STATUS) ||
  (stctl == (SCSW_STCTL_ALERT_STATUS | SCSW_STCTL_STATUS_PEND)) ||
  (stctl == SCSW_STCTL_STATUS_PEND);
 if (!ending_status &&
     !cdev->private->options.repall &&
     !(stctl & SCSW_STCTL_INTER_STATUS) &&
     !(cdev->private->options.fast &&
       (stctl & SCSW_STCTL_PRIM_STATUS)))
  return 0;

 if (ending_status)
  ccw_device_set_timeout(cdev, 0);

 if (cdev->handler)
  cdev->handler(cdev, cdev->private->intparm,
         &cdev->private->dma_area->irb);

 memset(&cdev->private->dma_area->irb, 0, sizeof(struct irb));
 return 1;
}

/*
 * Got an interrupt for a normal io (state online).
 */
static void
ccw_device_irq(struct ccw_device *cdev, enum dev_event dev_event)
{
 struct irb *irb;
 int is_cmd;

 irb = this_cpu_ptr(&cio_irb);
 is_cmd = !scsw_is_tm(&irb->scsw);
 /* Check for unsolicited interrupt. */
 if (!scsw_is_solicited(&irb->scsw)) {
  if (is_cmd && (irb->scsw.cmd.dstat & DEV_STAT_UNIT_CHECK) &&
      !irb->esw.esw0.erw.cons) {
   /* Unit check but no sense data. Need basic sense. */
   if (ccw_device_do_sense(cdev, irb) != 0)
    goto call_handler_unsol;
   memcpy(&cdev->private->dma_area->irb, irb,
          sizeof(struct irb));
   cdev->private->state = DEV_STATE_W4SENSE;
   cdev->private->intparm = 0;
   return;
  }
call_handler_unsol:
  if (cdev->handler)
   cdev->handler (cdev, 0, irb);
  if (cdev->private->flags.doverify)
   ccw_device_online_verify(cdev, 0);
  return;
 }
 /* Accumulate status and find out if a basic sense is needed. */
 ccw_device_accumulate_irb(cdev, irb);
 if (is_cmd && cdev->private->flags.dosense) {
  if (ccw_device_do_sense(cdev, irb) == 0) {
   cdev->private->state = DEV_STATE_W4SENSE;
  }
  return;
 }
 /* Call the handler. */
 if (ccw_device_call_handler(cdev) && cdev->private->flags.doverify)
  /* Start delayed path verification. */
  ccw_device_online_verify(cdev, 0);
}

/*
 * Got an timeout in online state.
 */
static void
ccw_device_online_timeout(struct ccw_device *cdev, enum dev_event dev_event)
{
 int ret;

 ccw_device_set_timeout(cdev, 0);
 cdev->private->iretry = 255;
 cdev->private->async_kill_io_rc = -ETIMEDOUT;
 ret = ccw_device_cancel_halt_clear(cdev);
 if (ret == -EBUSY) {
  ccw_device_set_timeout(cdev, 3*HZ);
  cdev->private->state = DEV_STATE_TIMEOUT_KILL;
  return;
 }
 if (ret)
  dev_fsm_event(cdev, DEV_EVENT_NOTOPER);
 else if (cdev->handler)
  cdev->handler(cdev, cdev->private->intparm,
         ERR_PTR(-ETIMEDOUT));
}

/*
 * Got an interrupt for a basic sense.
 */
static void
ccw_device_w4sense(struct ccw_device *cdev, enum dev_event dev_event)
{
 struct irb *irb;

 irb = this_cpu_ptr(&cio_irb);
 /* Check for unsolicited interrupt. */
 if (scsw_stctl(&irb->scsw) ==
     (SCSW_STCTL_STATUS_PEND | SCSW_STCTL_ALERT_STATUS)) {
  if (scsw_cc(&irb->scsw) == 1)
   /* Basic sense hasn't started. Try again. */
   ccw_device_do_sense(cdev, irb);
  else {
   CIO_MSG_EVENT(0, "0.%x.%04x: unsolicited "
          "interrupt during w4sense...\n",
          cdev->private->dev_id.ssid,
          cdev->private->dev_id.devno);
   if (cdev->handler)
    cdev->handler (cdev, 0, irb);
  }
  return;
 }
 /*
  * Check if a halt or clear has been issued in the meanwhile. If yes,
  * only deliver the halt/clear interrupt to the device driver as if it
  * had killed the original request.
 */
 if (scsw_fctl(&irb->scsw) &
     (SCSW_FCTL_CLEAR_FUNC | SCSW_FCTL_HALT_FUNC)) {
  cdev->private->flags.dosense = 0;
  memset(&cdev->private->dma_area->irb, 0, sizeof(struct irb));
  ccw_device_accumulate_irb(cdev, irb);
  goto call_handler;
 }
 /* Add basic sense info to irb. */
 ccw_device_accumulate_basic_sense(cdev, irb);
 if (cdev->private->flags.dosense) {
  /* Another basic sense is needed. */
  ccw_device_do_sense(cdev, irb);
  return;
 }
call_handler:
 cdev->private->state = DEV_STATE_ONLINE;
 /* In case sensing interfered with setting the device online */
 wake_up(&cdev->private->wait_q);
 /* Call the handler. */
 if (ccw_device_call_handler(cdev) && cdev->private->flags.doverify)
  /* Start delayed path verification. */
  ccw_device_online_verify(cdev, 0);
}

static void
ccw_device_killing_irq(struct ccw_device *cdev, enum dev_event dev_event)
{
 ccw_device_set_timeout(cdev, 0);
 /* Start delayed path verification. */
 ccw_device_online_verify(cdev, 0);
 /* OK, i/o is dead now. Call interrupt handler. */
 if (cdev->handler)
  cdev->handler(cdev, cdev->private->intparm,
         ERR_PTR(cdev->private->async_kill_io_rc));
}

static void
ccw_device_killing_timeout(struct ccw_device *cdev, enum dev_event dev_event)
{
 int ret;

 ret = ccw_device_cancel_halt_clear(cdev);
 if (ret == -EBUSY) {
  ccw_device_set_timeout(cdev, 3*HZ);
  return;
 }
 /* Start delayed path verification. */
 ccw_device_online_verify(cdev, 0);
 if (cdev->handler)
  cdev->handler(cdev, cdev->private->intparm,
         ERR_PTR(cdev->private->async_kill_io_rc));
}

void ccw_device_kill_io(struct ccw_device *cdev)
{
 int ret;

 ccw_device_set_timeout(cdev, 0);
 cdev->private->iretry = 255;
 cdev->private->async_kill_io_rc = -EIO;
 ret = ccw_device_cancel_halt_clear(cdev);
 if (ret == -EBUSY) {
  ccw_device_set_timeout(cdev, 3*HZ);
  cdev->private->state = DEV_STATE_TIMEOUT_KILL;
  return;
 }
 /* Start delayed path verification. */
 ccw_device_online_verify(cdev, 0);
 if (cdev->handler)
  cdev->handler(cdev, cdev->private->intparm,
         ERR_PTR(-EIO));
}

static void
ccw_device_delay_verify(struct ccw_device *cdev, enum dev_event dev_event)
{
 /* Start verification after current task finished. */
 cdev->private->flags.doverify = 1;
}

static void
ccw_device_start_id(struct ccw_device *cdev, enum dev_event dev_event)
{
 struct subchannel *sch;

 sch = to_subchannel(cdev->dev.parent);
 if (cio_enable_subchannel(sch, (u32)virt_to_phys(sch)) != 0)
  /* Couldn't enable the subchannel for i/o. Sick device. */
  return;
 cdev->private->state = DEV_STATE_DISCONNECTED_SENSE_ID;
 ccw_device_sense_id_start(cdev);
}

void ccw_device_trigger_reprobe(struct ccw_device *cdev)
{
 struct subchannel *sch;

 if (cdev->private->state != DEV_STATE_DISCONNECTED)
  return;

 sch = to_subchannel(cdev->dev.parent);
 /* Update some values. */
 if (cio_update_schib(sch))
  return;
 /*
  * The pim, pam, pom values may not be accurate, but they are the best
  * we have before performing device selection :/
 */
 sch->lpm = sch->schib.pmcw.pam & sch->opm;
 /*
  * Use the initial configuration since we can't be sure that the old
  * paths are valid.
 */
 io_subchannel_init_config(sch);
 if (cio_commit_config(sch))
  return;

 /* We should also udate ssd info, but this has to wait. */
 /* Check if this is another device which appeared on the same sch. */
 if (sch->schib.pmcw.dev != cdev->private->dev_id.devno)
  css_schedule_eval(sch->schid);
 else
  ccw_device_start_id(cdev, 0);
}

static void ccw_device_disabled_irq(struct ccw_device *cdev,
        enum dev_event dev_event)
{
 struct subchannel *sch;

 sch = to_subchannel(cdev->dev.parent);
 /*
  * An interrupt in a disabled state means a previous disable was not
  * successful - should not happen, but we try to disable again.
 */
 cio_disable_subchannel(sch);
}

static void
ccw_device_change_cmfstate(struct ccw_device *cdev, enum dev_event dev_event)
{
 retry_set_schib(cdev);
 cdev->private->state = DEV_STATE_ONLINE;
 dev_fsm_event(cdev, dev_event);
}

static void ccw_device_update_cmfblock(struct ccw_device *cdev,
           enum dev_event dev_event)
{
 cmf_retry_copy_block(cdev);
 cdev->private->state = DEV_STATE_ONLINE;
 dev_fsm_event(cdev, dev_event);
}

static void
ccw_device_quiesce_done(struct ccw_device *cdev, enum dev_event dev_event)
{
 ccw_device_set_timeout(cdev, 0);
 cdev->private->state = DEV_STATE_NOT_OPER;
 wake_up(&cdev->private->wait_q);
}

static void
ccw_device_quiesce_timeout(struct ccw_device *cdev, enum dev_event dev_event)
{
 int ret;

 ret = ccw_device_cancel_halt_clear(cdev);
 if (ret == -EBUSY) {
  ccw_device_set_timeout(cdev, HZ/10);
 } else {
  cdev->private->state = DEV_STATE_NOT_OPER;
  wake_up(&cdev->private->wait_q);
 }
}

/*
 * No operation action. This is used e.g. to ignore a timeout event in
 * state offline.
 */
static void
ccw_device_nop(struct ccw_device *cdev, enum dev_event dev_event)
{
}

/*
 * device statemachine
 */
fsm_func_t *dev_jumptable[NR_DEV_STATES][NR_DEV_EVENTS] = {
 [DEV_STATE_NOT_OPER] = {
  [DEV_EVENT_NOTOPER] = ccw_device_nop,
  [DEV_EVENT_INTERRUPT] = ccw_device_disabled_irq,
  [DEV_EVENT_TIMEOUT] = ccw_device_nop,
  [DEV_EVENT_VERIFY] = ccw_device_nop,
 },
 [DEV_STATE_SENSE_ID] = {
  [DEV_EVENT_NOTOPER] = ccw_device_request_event,
  [DEV_EVENT_INTERRUPT] = ccw_device_request_event,
  [DEV_EVENT_TIMEOUT] = ccw_device_request_event,
  [DEV_EVENT_VERIFY] = ccw_device_nop,
 },
 [DEV_STATE_OFFLINE] = {
  [DEV_EVENT_NOTOPER] = ccw_device_generic_notoper,
  [DEV_EVENT_INTERRUPT] = ccw_device_disabled_irq,
  [DEV_EVENT_TIMEOUT] = ccw_device_nop,
  [DEV_EVENT_VERIFY] = ccw_device_offline_verify,
 },
 [DEV_STATE_VERIFY] = {
  [DEV_EVENT_NOTOPER] = ccw_device_request_event,
  [DEV_EVENT_INTERRUPT] = ccw_device_request_event,
  [DEV_EVENT_TIMEOUT] = ccw_device_request_event,
  [DEV_EVENT_VERIFY] = ccw_device_delay_verify,
 },
 [DEV_STATE_ONLINE] = {
  [DEV_EVENT_NOTOPER] = ccw_device_generic_notoper,
  [DEV_EVENT_INTERRUPT] = ccw_device_irq,
  [DEV_EVENT_TIMEOUT] = ccw_device_online_timeout,
  [DEV_EVENT_VERIFY] = ccw_device_online_verify,
 },
 [DEV_STATE_W4SENSE] = {
  [DEV_EVENT_NOTOPER] = ccw_device_generic_notoper,
  [DEV_EVENT_INTERRUPT] = ccw_device_w4sense,
  [DEV_EVENT_TIMEOUT] = ccw_device_nop,
  [DEV_EVENT_VERIFY] = ccw_device_online_verify,
 },
 [DEV_STATE_DISBAND_PGID] = {
  [DEV_EVENT_NOTOPER] = ccw_device_request_event,
  [DEV_EVENT_INTERRUPT] = ccw_device_request_event,
  [DEV_EVENT_TIMEOUT] = ccw_device_request_event,
  [DEV_EVENT_VERIFY] = ccw_device_nop,
 },
 [DEV_STATE_BOXED] = {
  [DEV_EVENT_NOTOPER] = ccw_device_generic_notoper,
  [DEV_EVENT_INTERRUPT] = ccw_device_nop,
  [DEV_EVENT_TIMEOUT] = ccw_device_nop,
  [DEV_EVENT_VERIFY] = ccw_device_boxed_verify,
 },
 /* states to wait for i/o completion before doing something */
 [DEV_STATE_TIMEOUT_KILL] = {
  [DEV_EVENT_NOTOPER] = ccw_device_generic_notoper,
  [DEV_EVENT_INTERRUPT] = ccw_device_killing_irq,
  [DEV_EVENT_TIMEOUT] = ccw_device_killing_timeout,
  [DEV_EVENT_VERIFY] = ccw_device_nop, //FIXME
 },
 [DEV_STATE_QUIESCE] = {
  [DEV_EVENT_NOTOPER] = ccw_device_quiesce_done,
  [DEV_EVENT_INTERRUPT] = ccw_device_quiesce_done,
  [DEV_EVENT_TIMEOUT] = ccw_device_quiesce_timeout,
  [DEV_EVENT_VERIFY] = ccw_device_nop,
 },
 /* special states for devices gone not operational */
 [DEV_STATE_DISCONNECTED] = {
  [DEV_EVENT_NOTOPER] = ccw_device_nop,
  [DEV_EVENT_INTERRUPT] = ccw_device_start_id,
  [DEV_EVENT_TIMEOUT] = ccw_device_nop,
  [DEV_EVENT_VERIFY] = ccw_device_start_id,
 },
 [DEV_STATE_DISCONNECTED_SENSE_ID] = {
  [DEV_EVENT_NOTOPER] = ccw_device_request_event,
  [DEV_EVENT_INTERRUPT] = ccw_device_request_event,
  [DEV_EVENT_TIMEOUT] = ccw_device_request_event,
  [DEV_EVENT_VERIFY] = ccw_device_nop,
 },
 [DEV_STATE_CMFCHANGE] = {
  [DEV_EVENT_NOTOPER] = ccw_device_change_cmfstate,
  [DEV_EVENT_INTERRUPT] = ccw_device_change_cmfstate,
  [DEV_EVENT_TIMEOUT] = ccw_device_change_cmfstate,
  [DEV_EVENT_VERIFY] = ccw_device_change_cmfstate,
 },
 [DEV_STATE_CMFUPDATE] = {
  [DEV_EVENT_NOTOPER] = ccw_device_update_cmfblock,
  [DEV_EVENT_INTERRUPT] = ccw_device_update_cmfblock,
  [DEV_EVENT_TIMEOUT] = ccw_device_update_cmfblock,
  [DEV_EVENT_VERIFY] = ccw_device_update_cmfblock,
 },
 [DEV_STATE_STEAL_LOCK] = {
  [DEV_EVENT_NOTOPER] = ccw_device_request_event,
  [DEV_EVENT_INTERRUPT] = ccw_device_request_event,
  [DEV_EVENT_TIMEOUT] = ccw_device_request_event,
  [DEV_EVENT_VERIFY] = ccw_device_nop,
 },
};

EXPORT_SYMBOL_GPL(ccw_device_set_timeout);