x86/unwinder: Handle stack overflows more gracefully

[linux/fpc-iii.git] / drivers / s390 / cio / device_fsm.c

/*
 * 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/module.h>
#include <linux/init.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 %llx, "
               "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,
                               (void *)(addr_t)orb->tm.tcw,
                               sizeof(struct tcw), 0);
        } else {
                printk(KERN_WARNING "cio: orb indicates command mode\n");
                if ((void *)(addr_t)orb->cmd.cpa == &private->sense_ccw ||
                    (void *)(addr_t)orb->cmd.cpa == cdev->private->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,
                               (void *)(addr_t)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.
 */
static void
ccw_device_timeout(unsigned long data)
{
        struct ccw_device *cdev;

        cdev = (struct ccw_device *) data;
        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) {
                del_timer(&cdev->private->timer);
                return;
        }
        if (timer_pending(&cdev->private->timer)) {
                if (mod_timer(&cdev->private->timer, jiffies + expires))
                        return;
        }
        cdev->private->timer.function = ccw_device_timeout;
        cdev->private->timer.data = (unsigned long) cdev;
        cdev->private->timer.expires = jiffies + expires;
        add_timer(&cdev->private->timer);
}

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->senseid.cu_type;
        cdev->id.cu_model  = cdev->private->senseid.cu_model;
        cdev->id.dev_type  = cdev->private->senseid.dev_type;
        cdev->id.dev_model = cdev->private->senseid.dev_model;
}

int ccw_device_test_sense_data(struct ccw_device *cdev)
{
        return cdev->id.cu_type == cdev->private->senseid.cu_type &&
                cdev->id.cu_model == cdev->private->senseid.cu_model &&
                cdev->id.dev_type == cdev->private->senseid.dev_type &&
                cdev->id.dev_model == cdev->private->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;
        }
        if (cdev->private->flags.resuming) {
                cdev->private->state = state;
                cdev->private->flags.recog_done = 1;
                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) {
                /* Reenable 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->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) (addr_t) 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) {
                        create_fake_irb(&cdev->private->irb,
                                        cdev->private->flags.fake_irb);
                        cdev->private->flags.fake_irb = 0;
                        if (cdev->handler)
                                cdev->handler(cdev, cdev->private->intparm,
                                              &cdev->private->irb);
                        memset(&cdev->private->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)(addr_t)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->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) (addr_t) 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->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->irb);

        memset(&cdev->private->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->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;
        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->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(-EIO));
}

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(-EIO));
}

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

        cdev->private->iretry = 255;
        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)(addr_t)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 shure 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);