cio.c

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/*
 *   S/390 common I/O routines -- low level i/o calls
 *
 *    Copyright IBM Corp. 1999, 2008
 *    Author(s): Ingo Adlung ([email protected])
 *       Cornelia Huck ([email protected])
 *       Arnd Bergmann ([email protected])
 *       Martin Schwidefsky ([email protected])
 */

#define KMSG_COMPONENT "cio"
#define pr_fmt(fmt) KMSG_COMPONENT ": " fmt

#include <linux/ftrace.h>
#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 <asm/airq.h>
#include <asm/isc.h>
#include <asm/cputime.h>
#include <asm/fcx.h>
#include <asm/nmi.h>
#include <asm/crw.h>
#include "cio.h"
#include "css.h"
#include "chsc.h"
#include "ioasm.h"
#include "io_sch.h"
#include "blacklist.h"
#include "cio_debug.h"
#include "chp.h"

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

/*
 * Function: cio_debug_init
 * Initializes three debug logs for common I/O:
 * - cio_msg logs generic cio messages
 * - cio_trace logs the calling of different functions
 * - cio_crw logs machine check related cio messages
 */
static int __init cio_debug_init(void)
{
    cio_debug_msg_id = debug_register("cio_msg", 16, 1, 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, 1, 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", 16, 1, 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, 4);
    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);
    return -1;
}

arch_initcall (cio_debug_init);

int cio_set_options(struct subchannel *sch, int flags)
{
    struct io_subchannel_private *priv = to_io_private(sch);

    priv->options.suspend = (flags & DOIO_ALLOW_SUSPEND) != 0;
    priv->options.prefetch = (flags & DOIO_DENY_PREFETCH) != 0;
    priv->options.inter = (flags & DOIO_SUPPRESS_INTER) != 0;
    return 0;
}

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;

    CIO_MSG_EVENT(2, "cio_start: 'not oper' status for "
              "subchannel 0.%x.%04x!\n", sch->schid.ssid,
              sch->schid.sch_no);

    if (cio_update_schib(sch))
        return -ENODEV;

    sprintf(dbf_text, "no%s", dev_name(&sch->dev));
    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 */
{
    struct io_subchannel_private *priv = to_io_private(sch);
    union orb *orb = &priv->orb;
    int ccode;

    CIO_TRACE_EVENT(5, "stIO");
    CIO_TRACE_EVENT(5, dev_name(&sch->dev));

    memset(orb, 0, sizeof(union orb));
    /* sch is always under 2G. */
    orb->cmd.intparm = (u32)(addr_t)sch;
    orb->cmd.fmt = 1;

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

    /* process condition code */
    CIO_HEX_EVENT(5, &ccode, sizeof(ccode));

    switch (ccode) {
    case 0:
        /*
         * initialize device status information
         */
        sch->schib.scsw.cmd.actl |= SCSW_ACTL_START_PEND;
        return 0;
    case 1:     /* status pending */
    case 2:     /* busy */
        return -EBUSY;
    case 3:     /* device/path not operational */
        return cio_start_handle_notoper(sch, lpm);
    default:
        return ccode;
    }
}

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)
{
    int ccode;

    CIO_TRACE_EVENT(4, "resIO");
    CIO_TRACE_EVENT(4, dev_name(&sch->dev));

    ccode = rsch (sch->schid);

    CIO_HEX_EVENT(4, &ccode, sizeof(ccode));

    switch (ccode) {
    case 0:
        sch->schib.scsw.cmd.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)
{
    int ccode;

    if (!sch)
        return -ENODEV;

    CIO_TRACE_EVENT(2, "haltIO");
    CIO_TRACE_EVENT(2, dev_name(&sch->dev));

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

    CIO_HEX_EVENT(2, &ccode, sizeof(ccode));

    switch (ccode) {
    case 0:
        sch->schib.scsw.cmd.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)
{
    int ccode;

    if (!sch)
        return -ENODEV;

    CIO_TRACE_EVENT(2, "clearIO");
    CIO_TRACE_EVENT(2, dev_name(&sch->dev));

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

    CIO_HEX_EVENT(2, &ccode, sizeof(ccode));

    switch (ccode) {
    case 0:
        sch->schib.scsw.cmd.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)
{
    int ccode;

    if (!sch)
        return -ENODEV;

    CIO_TRACE_EVENT(2, "cancelIO");
    CIO_TRACE_EVENT(2, dev_name(&sch->dev));

    ccode = xsch (sch->schid);

    CIO_HEX_EVENT(2, &ccode, sizeof(ccode));

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


static void cio_apply_config(struct subchannel *sch, struct schib *schib)
{
    schib->pmcw.intparm = sch->config.intparm;
    schib->pmcw.mbi = sch->config.mbi;
    schib->pmcw.isc = sch->config.isc;
    schib->pmcw.ena = sch->config.ena;
    schib->pmcw.mme = sch->config.mme;
    schib->pmcw.mp = sch->config.mp;
    schib->pmcw.csense = sch->config.csense;
    schib->pmcw.mbfc = sch->config.mbfc;
    if (sch->config.mbfc)
        schib->mba = sch->config.mba;
}

static int cio_check_config(struct subchannel *sch, struct schib *schib)
{
    return (schib->pmcw.intparm == sch->config.intparm) &&
        (schib->pmcw.mbi == sch->config.mbi) &&
        (schib->pmcw.isc == sch->config.isc) &&
        (schib->pmcw.ena == sch->config.ena) &&
        (schib->pmcw.mme == sch->config.mme) &&
        (schib->pmcw.mp == sch->config.mp) &&
        (schib->pmcw.csense == sch->config.csense) &&
        (schib->pmcw.mbfc == sch->config.mbfc) &&
        (!sch->config.mbfc || (schib->mba == sch->config.mba));
}

/*
 * cio_commit_config - apply configuration to the subchannel
 */
int cio_commit_config(struct subchannel *sch)
{
    struct schib schib;
    int ccode, retry, ret = 0;

    if (stsch_err(sch->schid, &schib) || !css_sch_is_valid(&schib))
        return -ENODEV;

    for (retry = 0; retry < 5; retry++) {
        /* copy desired changes to local schib */
        cio_apply_config(sch, &schib);
        ccode = msch_err(sch->schid, &schib);
        if (ccode < 0) /* -EIO if msch gets a program check. */
            return ccode;
        switch (ccode) {
        case 0: /* successful */
            if (stsch_err(sch->schid, &schib) ||
                !css_sch_is_valid(&schib))
                return -ENODEV;
            if (cio_check_config(sch, &schib)) {
                /* commit changes from local schib */
                memcpy(&sch->schib, &schib, sizeof(schib));
                return 0;
            }
            ret = -EAGAIN;
            break;
        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;
}

int cio_update_schib(struct subchannel *sch)
{
    struct schib schib;

    if (stsch_err(sch->schid, &schib) || !css_sch_is_valid(&schib))
        return -ENODEV;

    memcpy(&sch->schib, &schib, sizeof(schib));
    return 0;
}
EXPORT_SYMBOL_GPL(cio_update_schib);

int cio_enable_subchannel(struct subchannel *sch, u32 intparm)
{
    int retry;
    int ret;

    CIO_TRACE_EVENT(2, "ensch");
    CIO_TRACE_EVENT(2, dev_name(&sch->dev));

    if (sch_is_pseudo_sch(sch))
        return -EINVAL;
    if (cio_update_schib(sch))
        return -ENODEV;

    sch->config.ena = 1;
    sch->config.isc = sch->isc;
    sch->config.intparm = intparm;

    for (retry = 0; retry < 3; retry++) {
        ret = cio_commit_config(sch);
        if (ret == -EIO) {
            /*
             * Got a program check in msch. Try without
             * the concurrent sense bit the next time.
             */
            sch->config.csense = 0;
        } else if (ret == -EBUSY) {
            struct irb irb;
            if (tsch(sch->schid, &irb) != 0)
                break;
        } else
            break;
    }
    CIO_HEX_EVENT(2, &ret, sizeof(ret));
    return ret;
}
EXPORT_SYMBOL_GPL(cio_enable_subchannel);

int cio_disable_subchannel(struct subchannel *sch)
{
    int retry;
    int ret;

    CIO_TRACE_EVENT(2, "dissch");
    CIO_TRACE_EVENT(2, dev_name(&sch->dev));

    if (sch_is_pseudo_sch(sch))
        return 0;
    if (cio_update_schib(sch))
        return -ENODEV;

    sch->config.ena = 0;

    for (retry = 0; retry < 3; retry++) {
        ret = cio_commit_config(sch);
        if (ret == -EBUSY) {
            struct irb irb;
            if (tsch(sch->schid, &irb) != 0)
                break;
        } else
            break;
    }
    CIO_HEX_EVENT(2, &ret, sizeof(ret));
    return ret;
}
EXPORT_SYMBOL_GPL(cio_disable_subchannel);

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;
}

static int cio_check_devno_blacklisted(struct subchannel *sch)
{
    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(6, "Blacklisted device detected "
                  "at devno %04X, subchannel set %x\n",
                  sch->schib.pmcw.dev, sch->schid.ssid);
        return -ENODEV;
    }
    return 0;
}

static int cio_validate_io_subchannel(struct subchannel *sch)
{
    /* Initialization for io subchannels. */
    if (!css_sch_is_valid(&sch->schib))
        return -ENODEV;

    /* Devno is valid. */
    return cio_check_devno_blacklisted(sch);
}

static int cio_validate_msg_subchannel(struct subchannel *sch)
{
    /* Initialization for message subchannels. */
    if (!css_sch_is_valid(&sch->schib))
        return -ENODEV;

    /* Devno is valid. */
    return cio_check_devno_blacklisted(sch);
}

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);

    /*
     * 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;

    switch (sch->st) {
    case SUBCHANNEL_TYPE_IO:
        err = cio_validate_io_subchannel(sch);
        break;
    case SUBCHANNEL_TYPE_MSG:
        err = cio_validate_msg_subchannel(sch);
        break;
    default:
        err = 0;
    }
    if (err)
        goto out;

    CIO_MSG_EVENT(4, "Subchannel 0.%x.%04x reports subchannel type %04X\n",
              sch->schid.ssid, sch->schid.sch_no, sch->st);
    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 __irq_entry 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();
    __this_cpu_write(s390_idle.nohz_delay, 1);
    if (S390_lowcore.int_clock >= S390_lowcore.clock_comparator)
        /* Serve timer interrupts first. */
        clock_comparator_work();
    /*
     * Get interrupt information from lowcore
     */
    tpi_info = (struct tpi_info *)&S390_lowcore.subchannel_id;
    irb = (struct irb *)&S390_lowcore.irb;
    do {
        kstat_cpu(smp_processor_id()).irqs[IO_INTERRUPT]++;
        if (tpi_info->adapter_IO) {
            do_adapter_IO(tpi_info->isc);
            continue;
        }
        sch = (struct subchannel *)(unsigned long)tpi_info->intparm;
        if (!sch) {
            /* Clear pending interrupt condition. */
            kstat_cpu(smp_processor_id()).irqs[IOINT_CIO]++;
            tsch(tpi_info->schid, irb);
            continue;
        }
        spin_lock(sch->lock);
        /* Store interrupt response block to lowcore. */
        if (tsch(tpi_info->schid, irb) == 0) {
            /* 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);
            else
                kstat_cpu(smp_processor_id()).irqs[IOINT_CIO]++;
        } else
            kstat_cpu(smp_processor_id()).irqs[IOINT_CIO]++;
        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_LPAR && tpi(NULL) != 0);
    irq_exit();
    set_irq_regs(old_regs);
}

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

/*
 * Use cio_tsch to update the subchannel status and call the interrupt handler
 * if status had been pending. Called with the console_subchannel lock.
 */
static void cio_tsch(struct subchannel *sch)
{
    struct irb *irb;
    int irq_context;

    irb = (struct irb *)&S390_lowcore.irb;
    /* Store interrupt response block to lowcore. */
    if (tsch(sch->schid, irb) != 0)
        /* Not status pending or not operational. */
        return;
    memcpy(&sch->schib.scsw, &irb->scsw, sizeof(union scsw));
    /* Call interrupt handler with updated status. */
    irq_context = in_interrupt();
    if (!irq_context) {
        local_bh_disable();
        irq_enter();
    }
    if (sch->driver && sch->driver->irq)
        sch->driver->irq(sch);
    else
        kstat_cpu(smp_processor_id()).irqs[IOINT_CIO]++;
    if (!irq_context) {
        irq_exit();
        _local_bh_enable();
    }
}

void *cio_get_console_priv(void)
{
    return &console_priv;
}

/*
 * busy wait for the next interrupt on the console
 */
void wait_cons_dev(void)
{
    if (!console_subchannel_in_use)
        return;

    while (1) {
        cio_tsch(&console_subchannel);
        if (console_subchannel.schib.scsw.cmd.actl == 0)
            break;
        udelay_simple(100);
    }
}

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.st == SUBCHANNEL_TYPE_IO) &&
        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_err(schid, &console_subchannel.schib) != 0 ||
            (console_subchannel.schib.pmcw.st != SUBCHANNEL_TYPE_IO) ||
            !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 */
        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;
        pr_warning("No CCW console was found\n");
        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
     */
    isc_register(CONSOLE_ISC);
    console_subchannel.config.isc = CONSOLE_ISC;
    console_subchannel.config.intparm = (u32)(addr_t)&console_subchannel;
    ret = cio_commit_config(&console_subchannel);
    if (ret) {
        isc_unregister(CONSOLE_ISC);
        console_subchannel_in_use = 0;
        return ERR_PTR(ret);
    }
    return &console_subchannel;
}

void
cio_release_console(void)
{
    console_subchannel.config.intparm = 0;
    cio_commit_config(&console_subchannel);
    isc_unregister(CONSOLE_ISC);
    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_err(schid, schib);
        if (cc)
            return (cc==3?-ENODEV:-EBUSY);
        if (stsch_err(schid, schib) || !css_sch_is_valid(schib))
            return -ENODEV;
        if (!schib->pmcw.ena)
            return 0;
    }
    return -EBUSY; /* uhm... */
}

static int
__clear_io_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 *)&S390_lowcore.irb);
            if (schid_equal(&ti.schid, &schid))
                return 0;
        }
        udelay_simple(100);
    }
    return -EBUSY;
}

static void __clear_chsc_subchannel_easy(void)
{
    /* It seems we can only wait for a bit here :/ */
    udelay_simple(100);
}

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, struct schib *addr)
{
    int rc;

    pgm_check_occured = 0;
    s390_base_pgm_handler_fn = cio_reset_pgm_check_handler;
    rc = stsch_err(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 */
        switch (schib.pmcw.st) {
        case SUBCHANNEL_TYPE_IO:
            if (__clear_io_subchannel_easy(schid))
                goto out; /* give up... */
            break;
        case SUBCHANNEL_TYPE_CHSC:
            __clear_chsc_subchannel_easy();
            break;
        default:
            /* No default clear strategy */
            break;
        }
        stsch_err(schid, &schib);
        __disable_subchannel_easy(schid, &schib);
    }
out:
    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.st == SUBCHANNEL_TYPE_IO) && 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 uninitialized_var(schid);

    s390_reset_system(NULL, NULL);
    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 *)&S390_lowcore.subchannel_id;
    if (!schid.one)
        return -ENODEV;
    if (stsch_err(schid, &schib))
        return -ENODEV;
    if (schib.pmcw.st != SUBCHANNEL_TYPE_IO)
        return -ENODEV;
    if (!schib.pmcw.dnv)
        return -ENODEV;
    iplinfo->devno = schib.pmcw.dev;
    iplinfo->is_qdio = schib.pmcw.qf;
    return 0;
}

int cio_tm_start_key(struct subchannel *sch, struct tcw *tcw, u8 lpm, u8 key)
{
    int cc;
    union orb *orb = &to_io_private(sch)->orb;

    memset(orb, 0, sizeof(union orb));
    orb->tm.intparm = (u32) (addr_t) sch;
    orb->tm.key = key >> 4;
    orb->tm.b = 1;
    orb->tm.lpm = lpm ? lpm : sch->lpm;
    orb->tm.tcw = (u32) (addr_t) tcw;
    cc = ssch(sch->schid, orb);
    switch (cc) {
    case 0:
        return 0;
    case 1:
    case 2:
        return -EBUSY;
    default:
        return cio_start_handle_notoper(sch, lpm);
    }
}

int cio_tm_intrg(struct subchannel *sch)
{
    int cc;

    if (!to_io_private(sch)->orb.tm.b)
        return -EINVAL;
    cc = xsch(sch->schid);
    switch (cc) {
    case 0:
    case 2:
        return 0;
    case 1:
        return -EBUSY;
    default:
        return -ENODEV;
    }
}