omap: i2c: add a timeout to the busy waiting

[linux-2.6/linux-acpi-2.6/ibm-acpi-2.6.git] / drivers / s390 / cio / cio.c

/*
 *  drivers/s390/cio/cio.c
 *   S/390 common I/O routines -- low level i/o calls
 *
 *    Copyright IBM Corp. 1999,2008
 *    Author(s): Ingo Adlung (adlung@de.ibm.com)
 *               Cornelia Huck (cornelia.huck@de.ibm.com)
 *               Arnd Bergmann (arndb@de.ibm.com)
 *               Martin Schwidefsky (schwidefsky@de.ibm.com)
 */

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

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

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

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 */
{
        int ccode;
        union orb *orb;

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

        orb = &to_io_private(sch)->orb;
        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 = sch->options.prefetch == 0;
        orb->cmd.spnd = sch->options.suspend;
        orb->cmd.ssic = sch->options.suspend && sch->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;
}

/**
 * cio_update_schib - Perform stsch and update schib if subchannel is valid.
 * @sch: subchannel on which to perform stsch
 * Return zero on success, -ENODEV otherwise.
 */
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);

/**
 * cio_enable_subchannel - enable a subchannel.
 * @sch: subchannel to be enabled
 * @intparm: interruption parameter to set
 */
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);

/**
 * cio_disable_subchannel - disable a subchannel.
 * @sch: subchannel to disable
 */
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);
}

/**
 * cio_validate_subchannel - basic validation of subchannel
 * @sch: subchannel structure to be filled out
 * @schid: subchannel id
 *
 * Find out subchannel type and initialize struct subchannel.
 * Return codes:
 *   0 on success
 *   -ENXIO for non-defined subchannels
 *   -ENODEV for invalid subchannels or blacklisted devices
 *   -EIO for subchannels in an invalid subchannel set
 */
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);
        s390_idle_check(regs, S390_lowcore.int_clock,
                        S390_lowcore.async_enter_timer);
        irq_enter();
        __get_cpu_var(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]++;
                /*
                 * Non I/O-subchannel thin interrupts are processed differently
                 */
                if (tpi_info->adapter_IO == 1 &&
                    tpi_info->int_type == IO_INTERRUPT_TYPE) {
                        do_adapter_IO(tpi_info->isc);
                        continue;
                }
                sch = (struct subchannel *)(unsigned long)tpi_info->intparm;
                if (!sch) {
                        /* Clear pending interrupt condition. */
                        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);
                }
                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 tpi to get a pending interrupt, call the interrupt handler and
 * return a pointer to the subchannel structure.
 */
static int cio_tpi(void)
{
        struct tpi_info *tpi_info;
        struct subchannel *sch;
        struct irb *irb;
        int irq_context;

        tpi_info = (struct tpi_info *)&S390_lowcore.subchannel_id;
        if (tpi(NULL) != 1)
                return 0;
        irb = (struct irb *)&S390_lowcore.irb;
        /* Store interrupt response block to lowcore. */
        if (tsch(tpi_info->schid, irb) != 0)
                /* Not status pending or not operational. */
                return 1;
        sch = (struct subchannel *)(unsigned long)tpi_info->intparm;
        if (!sch)
                return 1;
        irq_context = in_interrupt();
        if (!irq_context)
                local_bh_disable();
        irq_enter();
        spin_lock(sch->lock);
        memcpy(&sch->schib.scsw, &irb->scsw, sizeof(union scsw));
        if (sch->driver && sch->driver->irq)
                sch->driver->irq(sch);
        spin_unlock(sch->lock);
        irq_exit();
        if (!irq_context)
                _local_bh_enable();
        return 1;
}

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

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

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

        /* disable all but the console isc */
        __ctl_store (save_cr6, 6, 6);
        cr6 = 1UL << (31 - CONSOLE_ISC);
        __ctl_load (cr6, 6, 6);

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

static int
cio_test_for_console(struct subchannel_id schid, void *data)
{
        if (stsch_err(schid, &console_subchannel.schib) != 0)
                return -ENXIO;
        if ((console_subchannel.schib.pmcw.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 schid;

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

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

        schid = *(struct subchannel_id *)&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;
}

/**
 * cio_tm_start_key - perform start function
 * @sch: subchannel on which to perform the start function
 * @tcw: transport-command word to be started
 * @lpm: mask of paths to use
 * @key: storage key to use for storage access
 *
 * Start the tcw on the given subchannel. Return zero on success, non-zero
 * otherwise.
 */
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);
        }
}

/**
 * cio_tm_intrg - perform interrogate function
 * @sch - subchannel on which to perform the interrogate function
 *
 * If the specified subchannel is running in transport-mode, perform the
 * interrogate function. Return zero on success, non-zero otherwie.
 */
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;
        }
}