Merge branch 'akpm'

[linux-2.6/next.git] / drivers / s390 / cio / device_ops.c

/*
 * Copyright IBM Corp. 2002, 2009
 *
 * Author(s): Martin Schwidefsky (schwidefsky@de.ibm.com)
 *            Cornelia Huck (cornelia.huck@de.ibm.com)
 */
#include <linux/module.h>
#include <linux/init.h>
#include <linux/errno.h>
#include <linux/slab.h>
#include <linux/list.h>
#include <linux/device.h>
#include <linux/delay.h>
#include <linux/completion.h>

#include <asm/ccwdev.h>
#include <asm/idals.h>
#include <asm/chpid.h>
#include <asm/fcx.h>

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

/**
 * ccw_device_set_options_mask() - set some options and unset the rest
 * @cdev: device for which the options are to be set
 * @flags: options to be set
 *
 * All flags specified in @flags are set, all flags not specified in @flags
 * are cleared.
 * Returns:
 *   %0 on success, -%EINVAL on an invalid flag combination.
 */
int ccw_device_set_options_mask(struct ccw_device *cdev, unsigned long flags)
{
       /*
        * The flag usage is mutal exclusive ...
        */
        if ((flags & CCWDEV_EARLY_NOTIFICATION) &&
            (flags & CCWDEV_REPORT_ALL))
                return -EINVAL;
        cdev->private->options.fast = (flags & CCWDEV_EARLY_NOTIFICATION) != 0;
        cdev->private->options.repall = (flags & CCWDEV_REPORT_ALL) != 0;
        cdev->private->options.pgroup = (flags & CCWDEV_DO_PATHGROUP) != 0;
        cdev->private->options.force = (flags & CCWDEV_ALLOW_FORCE) != 0;
        cdev->private->options.mpath = (flags & CCWDEV_DO_MULTIPATH) != 0;
        return 0;
}

/**
 * ccw_device_set_options() - set some options
 * @cdev: device for which the options are to be set
 * @flags: options to be set
 *
 * All flags specified in @flags are set, the remainder is left untouched.
 * Returns:
 *   %0 on success, -%EINVAL if an invalid flag combination would ensue.
 */
int ccw_device_set_options(struct ccw_device *cdev, unsigned long flags)
{
       /*
        * The flag usage is mutal exclusive ...
        */
        if (((flags & CCWDEV_EARLY_NOTIFICATION) &&
            (flags & CCWDEV_REPORT_ALL)) ||
            ((flags & CCWDEV_EARLY_NOTIFICATION) &&
             cdev->private->options.repall) ||
            ((flags & CCWDEV_REPORT_ALL) &&
             cdev->private->options.fast))
                return -EINVAL;
        cdev->private->options.fast |= (flags & CCWDEV_EARLY_NOTIFICATION) != 0;
        cdev->private->options.repall |= (flags & CCWDEV_REPORT_ALL) != 0;
        cdev->private->options.pgroup |= (flags & CCWDEV_DO_PATHGROUP) != 0;
        cdev->private->options.force |= (flags & CCWDEV_ALLOW_FORCE) != 0;
        cdev->private->options.mpath |= (flags & CCWDEV_DO_MULTIPATH) != 0;
        return 0;
}

/**
 * ccw_device_clear_options() - clear some options
 * @cdev: device for which the options are to be cleared
 * @flags: options to be cleared
 *
 * All flags specified in @flags are cleared, the remainder is left untouched.
 */
void ccw_device_clear_options(struct ccw_device *cdev, unsigned long flags)
{
        cdev->private->options.fast &= (flags & CCWDEV_EARLY_NOTIFICATION) == 0;
        cdev->private->options.repall &= (flags & CCWDEV_REPORT_ALL) == 0;
        cdev->private->options.pgroup &= (flags & CCWDEV_DO_PATHGROUP) == 0;
        cdev->private->options.force &= (flags & CCWDEV_ALLOW_FORCE) == 0;
        cdev->private->options.mpath &= (flags & CCWDEV_DO_MULTIPATH) == 0;
}

/**
 * ccw_device_is_pathgroup - determine if paths to this device are grouped
 * @cdev: ccw device
 *
 * Return non-zero if there is a path group, zero otherwise.
 */
int ccw_device_is_pathgroup(struct ccw_device *cdev)
{
        return cdev->private->flags.pgroup;
}
EXPORT_SYMBOL(ccw_device_is_pathgroup);

/**
 * ccw_device_is_multipath - determine if device is operating in multipath mode
 * @cdev: ccw device
 *
 * Return non-zero if device is operating in multipath mode, zero otherwise.
 */
int ccw_device_is_multipath(struct ccw_device *cdev)
{
        return cdev->private->flags.mpath;
}
EXPORT_SYMBOL(ccw_device_is_multipath);

/**
 * ccw_device_clear() - terminate I/O request processing
 * @cdev: target ccw device
 * @intparm: interruption parameter; value is only used if no I/O is
 *           outstanding, otherwise the intparm associated with the I/O request
 *           is returned
 *
 * ccw_device_clear() calls csch on @cdev's subchannel.
 * Returns:
 *  %0 on success,
 *  -%ENODEV on device not operational,
 *  -%EINVAL on invalid device state.
 * Context:
 *  Interrupts disabled, ccw device lock held
 */
int ccw_device_clear(struct ccw_device *cdev, unsigned long intparm)
{
        struct subchannel *sch;
        int ret;

        if (!cdev || !cdev->dev.parent)
                return -ENODEV;
        sch = to_subchannel(cdev->dev.parent);
        if (!sch->schib.pmcw.ena)
                return -EINVAL;
        if (cdev->private->state == DEV_STATE_NOT_OPER)
                return -ENODEV;
        if (cdev->private->state != DEV_STATE_ONLINE &&
            cdev->private->state != DEV_STATE_W4SENSE)
                return -EINVAL;

        ret = cio_clear(sch);
        if (ret == 0)
                cdev->private->intparm = intparm;
        return ret;
}

/**
 * ccw_device_start_key() - start a s390 channel program with key
 * @cdev: target ccw device
 * @cpa: logical start address of channel program
 * @intparm: user specific interruption parameter; will be presented back to
 *           @cdev's interrupt handler. Allows a device driver to associate
 *           the interrupt with a particular I/O request.
 * @lpm: defines the channel path to be used for a specific I/O request. A
 *       value of 0 will make cio use the opm.
 * @key: storage key to be used for the I/O
 * @flags: additional flags; defines the action to be performed for I/O
 *         processing.
 *
 * Start a S/390 channel program. When the interrupt arrives, the
 * IRQ handler is called, either immediately, delayed (dev-end missing,
 * or sense required) or never (no IRQ handler registered).
 * Returns:
 *  %0, if the operation was successful;
 *  -%EBUSY, if the device is busy, or status pending;
 *  -%EACCES, if no path specified in @lpm is operational;
 *  -%ENODEV, if the device is not operational.
 * Context:
 *  Interrupts disabled, ccw device lock held
 */
int ccw_device_start_key(struct ccw_device *cdev, struct ccw1 *cpa,
                         unsigned long intparm, __u8 lpm, __u8 key,
                         unsigned long flags)
{
        struct subchannel *sch;
        int ret;

        if (!cdev || !cdev->dev.parent)
                return -ENODEV;
        sch = to_subchannel(cdev->dev.parent);
        if (!sch->schib.pmcw.ena)
                return -EINVAL;
        if (cdev->private->state == DEV_STATE_NOT_OPER)
                return -ENODEV;
        if (cdev->private->state == DEV_STATE_VERIFY) {
                /* Remember to fake irb when finished. */
                if (!cdev->private->flags.fake_irb) {
                        cdev->private->flags.fake_irb = 1;
                        cdev->private->intparm = intparm;
                        return 0;
                } else
                        /* There's already a fake I/O around. */
                        return -EBUSY;
        }
        if (cdev->private->state != DEV_STATE_ONLINE ||
            ((sch->schib.scsw.cmd.stctl & SCSW_STCTL_PRIM_STATUS) &&
             !(sch->schib.scsw.cmd.stctl & SCSW_STCTL_SEC_STATUS)) ||
            cdev->private->flags.doverify)
                return -EBUSY;
        ret = cio_set_options (sch, flags);
        if (ret)
                return ret;
        /* Adjust requested path mask to excluded varied off paths. */
        if (lpm) {
                lpm &= sch->opm;
                if (lpm == 0)
                        return -EACCES;
        }
        ret = cio_start_key (sch, cpa, lpm, key);
        switch (ret) {
        case 0:
                cdev->private->intparm = intparm;
                break;
        case -EACCES:
        case -ENODEV:
                dev_fsm_event(cdev, DEV_EVENT_VERIFY);
                break;
        }
        return ret;
}

/**
 * ccw_device_start_timeout_key() - start a s390 channel program with timeout and key
 * @cdev: target ccw device
 * @cpa: logical start address of channel program
 * @intparm: user specific interruption parameter; will be presented back to
 *           @cdev's interrupt handler. Allows a device driver to associate
 *           the interrupt with a particular I/O request.
 * @lpm: defines the channel path to be used for a specific I/O request. A
 *       value of 0 will make cio use the opm.
 * @key: storage key to be used for the I/O
 * @flags: additional flags; defines the action to be performed for I/O
 *         processing.
 * @expires: timeout value in jiffies
 *
 * Start a S/390 channel program. When the interrupt arrives, the
 * IRQ handler is called, either immediately, delayed (dev-end missing,
 * or sense required) or never (no IRQ handler registered).
 * This function notifies the device driver if the channel program has not
 * completed during the time specified by @expires. If a timeout occurs, the
 * channel program is terminated via xsch, hsch or csch, and the device's
 * interrupt handler will be called with an irb containing ERR_PTR(-%ETIMEDOUT).
 * Returns:
 *  %0, if the operation was successful;
 *  -%EBUSY, if the device is busy, or status pending;
 *  -%EACCES, if no path specified in @lpm is operational;
 *  -%ENODEV, if the device is not operational.
 * Context:
 *  Interrupts disabled, ccw device lock held
 */
int ccw_device_start_timeout_key(struct ccw_device *cdev, struct ccw1 *cpa,
                                 unsigned long intparm, __u8 lpm, __u8 key,
                                 unsigned long flags, int expires)
{
        int ret;

        if (!cdev)
                return -ENODEV;
        ccw_device_set_timeout(cdev, expires);
        ret = ccw_device_start_key(cdev, cpa, intparm, lpm, key, flags);
        if (ret != 0)
                ccw_device_set_timeout(cdev, 0);
        return ret;
}

/**
 * ccw_device_start() - start a s390 channel program
 * @cdev: target ccw device
 * @cpa: logical start address of channel program
 * @intparm: user specific interruption parameter; will be presented back to
 *           @cdev's interrupt handler. Allows a device driver to associate
 *           the interrupt with a particular I/O request.
 * @lpm: defines the channel path to be used for a specific I/O request. A
 *       value of 0 will make cio use the opm.
 * @flags: additional flags; defines the action to be performed for I/O
 *         processing.
 *
 * Start a S/390 channel program. When the interrupt arrives, the
 * IRQ handler is called, either immediately, delayed (dev-end missing,
 * or sense required) or never (no IRQ handler registered).
 * Returns:
 *  %0, if the operation was successful;
 *  -%EBUSY, if the device is busy, or status pending;
 *  -%EACCES, if no path specified in @lpm is operational;
 *  -%ENODEV, if the device is not operational.
 * Context:
 *  Interrupts disabled, ccw device lock held
 */
int ccw_device_start(struct ccw_device *cdev, struct ccw1 *cpa,
                     unsigned long intparm, __u8 lpm, unsigned long flags)
{
        return ccw_device_start_key(cdev, cpa, intparm, lpm,
                                    PAGE_DEFAULT_KEY, flags);
}

/**
 * ccw_device_start_timeout() - start a s390 channel program with timeout
 * @cdev: target ccw device
 * @cpa: logical start address of channel program
 * @intparm: user specific interruption parameter; will be presented back to
 *           @cdev's interrupt handler. Allows a device driver to associate
 *           the interrupt with a particular I/O request.
 * @lpm: defines the channel path to be used for a specific I/O request. A
 *       value of 0 will make cio use the opm.
 * @flags: additional flags; defines the action to be performed for I/O
 *         processing.
 * @expires: timeout value in jiffies
 *
 * Start a S/390 channel program. When the interrupt arrives, the
 * IRQ handler is called, either immediately, delayed (dev-end missing,
 * or sense required) or never (no IRQ handler registered).
 * This function notifies the device driver if the channel program has not
 * completed during the time specified by @expires. If a timeout occurs, the
 * channel program is terminated via xsch, hsch or csch, and the device's
 * interrupt handler will be called with an irb containing ERR_PTR(-%ETIMEDOUT).
 * Returns:
 *  %0, if the operation was successful;
 *  -%EBUSY, if the device is busy, or status pending;
 *  -%EACCES, if no path specified in @lpm is operational;
 *  -%ENODEV, if the device is not operational.
 * Context:
 *  Interrupts disabled, ccw device lock held
 */
int ccw_device_start_timeout(struct ccw_device *cdev, struct ccw1 *cpa,
                             unsigned long intparm, __u8 lpm,
                             unsigned long flags, int expires)
{
        return ccw_device_start_timeout_key(cdev, cpa, intparm, lpm,
                                            PAGE_DEFAULT_KEY, flags,
                                            expires);
}


/**
 * ccw_device_halt() - halt I/O request processing
 * @cdev: target ccw device
 * @intparm: interruption parameter; value is only used if no I/O is
 *           outstanding, otherwise the intparm associated with the I/O request
 *           is returned
 *
 * ccw_device_halt() calls hsch on @cdev's subchannel.
 * Returns:
 *  %0 on success,
 *  -%ENODEV on device not operational,
 *  -%EINVAL on invalid device state,
 *  -%EBUSY on device busy or interrupt pending.
 * Context:
 *  Interrupts disabled, ccw device lock held
 */
int ccw_device_halt(struct ccw_device *cdev, unsigned long intparm)
{
        struct subchannel *sch;
        int ret;

        if (!cdev || !cdev->dev.parent)
                return -ENODEV;
        sch = to_subchannel(cdev->dev.parent);
        if (!sch->schib.pmcw.ena)
                return -EINVAL;
        if (cdev->private->state == DEV_STATE_NOT_OPER)
                return -ENODEV;
        if (cdev->private->state != DEV_STATE_ONLINE &&
            cdev->private->state != DEV_STATE_W4SENSE)
                return -EINVAL;

        ret = cio_halt(sch);
        if (ret == 0)
                cdev->private->intparm = intparm;
        return ret;
}

/**
 * ccw_device_resume() - resume channel program execution
 * @cdev: target ccw device
 *
 * ccw_device_resume() calls rsch on @cdev's subchannel.
 * Returns:
 *  %0 on success,
 *  -%ENODEV on device not operational,
 *  -%EINVAL on invalid device state,
 *  -%EBUSY on device busy or interrupt pending.
 * Context:
 *  Interrupts disabled, ccw device lock held
 */
int ccw_device_resume(struct ccw_device *cdev)
{
        struct subchannel *sch;

        if (!cdev || !cdev->dev.parent)
                return -ENODEV;
        sch = to_subchannel(cdev->dev.parent);
        if (!sch->schib.pmcw.ena)
                return -EINVAL;
        if (cdev->private->state == DEV_STATE_NOT_OPER)
                return -ENODEV;
        if (cdev->private->state != DEV_STATE_ONLINE ||
            !(sch->schib.scsw.cmd.actl & SCSW_ACTL_SUSPENDED))
                return -EINVAL;
        return cio_resume(sch);
}

/*
 * Pass interrupt to device driver.
 */
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;

        /* Clear pending timers for device driver initiated I/O. */
        if (ending_status)
                ccw_device_set_timeout(cdev, 0);
        /*
         * Now we are ready to call the device driver interrupt handler.
         */
        if (cdev->handler)
                cdev->handler(cdev, cdev->private->intparm,
                              &cdev->private->irb);

        /*
         * Clear the old and now useless interrupt response block.
         */
        memset(&cdev->private->irb, 0, sizeof(struct irb));

        return 1;
}

/**
 * ccw_device_get_ciw() - Search for CIW command in extended sense data.
 * @cdev: ccw device to inspect
 * @ct: command type to look for
 *
 * During SenseID, command information words (CIWs) describing special
 * commands available to the device may have been stored in the extended
 * sense data. This function searches for CIWs of a specified command
 * type in the extended sense data.
 * Returns:
 *  %NULL if no extended sense data has been stored or if no CIW of the
 *  specified command type could be found,
 *  else a pointer to the CIW of the specified command type.
 */
struct ciw *ccw_device_get_ciw(struct ccw_device *cdev, __u32 ct)
{
        int ciw_cnt;

        if (cdev->private->flags.esid == 0)
                return NULL;
        for (ciw_cnt = 0; ciw_cnt < MAX_CIWS; ciw_cnt++)
                if (cdev->private->senseid.ciw[ciw_cnt].ct == ct)
                        return cdev->private->senseid.ciw + ciw_cnt;
        return NULL;
}

/**
 * ccw_device_get_path_mask() - get currently available paths
 * @cdev: ccw device to be queried
 * Returns:
 *  %0 if no subchannel for the device is available,
 *  else the mask of currently available paths for the ccw device's subchannel.
 */
__u8 ccw_device_get_path_mask(struct ccw_device *cdev)
{
        struct subchannel *sch;

        if (!cdev->dev.parent)
                return 0;

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

struct stlck_data {
        struct completion done;
        int rc;
};

void ccw_device_stlck_done(struct ccw_device *cdev, void *data, int rc)
{
        struct stlck_data *sdata = data;

        sdata->rc = rc;
        complete(&sdata->done);
}

/*
 * Perform unconditional reserve + release.
 */
int ccw_device_stlck(struct ccw_device *cdev)
{
        struct subchannel *sch = to_subchannel(cdev->dev.parent);
        struct stlck_data data;
        u8 *buffer;
        int rc;

        /* Check if steal lock operation is valid for this device. */
        if (cdev->drv) {
                if (!cdev->private->options.force)
                        return -EINVAL;
        }
        buffer = kzalloc(64, GFP_DMA | GFP_KERNEL);
        if (!buffer)
                return -ENOMEM;
        init_completion(&data.done);
        data.rc = -EIO;
        spin_lock_irq(sch->lock);
        rc = cio_enable_subchannel(sch, (u32) (addr_t) sch);
        if (rc)
                goto out_unlock;
        /* Perform operation. */
        cdev->private->state = DEV_STATE_STEAL_LOCK,
        ccw_device_stlck_start(cdev, &data, &buffer[0], &buffer[32]);
        spin_unlock_irq(sch->lock);
        /* Wait for operation to finish. */
        if (wait_for_completion_interruptible(&data.done)) {
                /* Got a signal. */
                spin_lock_irq(sch->lock);
                ccw_request_cancel(cdev);
                spin_unlock_irq(sch->lock);
                wait_for_completion(&data.done);
        }
        rc = data.rc;
        /* Check results. */
        spin_lock_irq(sch->lock);
        cio_disable_subchannel(sch);
        cdev->private->state = DEV_STATE_BOXED;
out_unlock:
        spin_unlock_irq(sch->lock);
        kfree(buffer);

        return rc;
}

void *ccw_device_get_chp_desc(struct ccw_device *cdev, int chp_no)
{
        struct subchannel *sch;
        struct chp_id chpid;

        sch = to_subchannel(cdev->dev.parent);
        chp_id_init(&chpid);
        chpid.id = sch->schib.pmcw.chpid[chp_no];
        return chp_get_chp_desc(chpid);
}

/**
 * ccw_device_get_id - obtain a ccw device id
 * @cdev: device to obtain the id for
 * @dev_id: where to fill in the values
 */
void ccw_device_get_id(struct ccw_device *cdev, struct ccw_dev_id *dev_id)
{
        *dev_id = cdev->private->dev_id;
}
EXPORT_SYMBOL(ccw_device_get_id);

/**
 * ccw_device_tm_start_key - perform start function
 * @cdev: ccw device on which to perform the start function
 * @tcw: transport-command word to be started
 * @intparm: user defined parameter to be passed to the interrupt handler
 * @lpm: mask of paths to use
 * @key: storage key to use for storage access
 *
 * Start the tcw on the given ccw device. Return zero on success, non-zero
 * otherwise.
 */
int ccw_device_tm_start_key(struct ccw_device *cdev, struct tcw *tcw,
                            unsigned long intparm, u8 lpm, u8 key)
{
        struct subchannel *sch;
        int rc;

        sch = to_subchannel(cdev->dev.parent);
        if (!sch->schib.pmcw.ena)
                return -EINVAL;
        if (cdev->private->state != DEV_STATE_ONLINE)
                return -EIO;
        /* Adjust requested path mask to excluded varied off paths. */
        if (lpm) {
                lpm &= sch->opm;
                if (lpm == 0)
                        return -EACCES;
        }
        rc = cio_tm_start_key(sch, tcw, lpm, key);
        if (rc == 0)
                cdev->private->intparm = intparm;
        return rc;
}
EXPORT_SYMBOL(ccw_device_tm_start_key);

/**
 * ccw_device_tm_start_timeout_key - perform start function
 * @cdev: ccw device on which to perform the start function
 * @tcw: transport-command word to be started
 * @intparm: user defined parameter to be passed to the interrupt handler
 * @lpm: mask of paths to use
 * @key: storage key to use for storage access
 * @expires: time span in jiffies after which to abort request
 *
 * Start the tcw on the given ccw device. Return zero on success, non-zero
 * otherwise.
 */
int ccw_device_tm_start_timeout_key(struct ccw_device *cdev, struct tcw *tcw,
                                    unsigned long intparm, u8 lpm, u8 key,
                                    int expires)
{
        int ret;

        ccw_device_set_timeout(cdev, expires);
        ret = ccw_device_tm_start_key(cdev, tcw, intparm, lpm, key);
        if (ret != 0)
                ccw_device_set_timeout(cdev, 0);
        return ret;
}
EXPORT_SYMBOL(ccw_device_tm_start_timeout_key);

/**
 * ccw_device_tm_start - perform start function
 * @cdev: ccw device on which to perform the start function
 * @tcw: transport-command word to be started
 * @intparm: user defined parameter to be passed to the interrupt handler
 * @lpm: mask of paths to use
 *
 * Start the tcw on the given ccw device. Return zero on success, non-zero
 * otherwise.
 */
int ccw_device_tm_start(struct ccw_device *cdev, struct tcw *tcw,
                        unsigned long intparm, u8 lpm)
{
        return ccw_device_tm_start_key(cdev, tcw, intparm, lpm,
                                       PAGE_DEFAULT_KEY);
}
EXPORT_SYMBOL(ccw_device_tm_start);

/**
 * ccw_device_tm_start_timeout - perform start function
 * @cdev: ccw device on which to perform the start function
 * @tcw: transport-command word to be started
 * @intparm: user defined parameter to be passed to the interrupt handler
 * @lpm: mask of paths to use
 * @expires: time span in jiffies after which to abort request
 *
 * Start the tcw on the given ccw device. Return zero on success, non-zero
 * otherwise.
 */
int ccw_device_tm_start_timeout(struct ccw_device *cdev, struct tcw *tcw,
                               unsigned long intparm, u8 lpm, int expires)
{
        return ccw_device_tm_start_timeout_key(cdev, tcw, intparm, lpm,
                                               PAGE_DEFAULT_KEY, expires);
}
EXPORT_SYMBOL(ccw_device_tm_start_timeout);

/**
 * ccw_device_get_mdc - accumulate max data count
 * @cdev: ccw device for which the max data count is accumulated
 * @mask: mask of paths to use
 *
 * Return the number of 64K-bytes blocks all paths at least support
 * for a transport command. Return values <= 0 indicate failures.
 */
int ccw_device_get_mdc(struct ccw_device *cdev, u8 mask)
{
        struct subchannel *sch = to_subchannel(cdev->dev.parent);
        struct channel_path_desc_fmt1 desc;
        struct chp_id chpid;
        int mdc = 0, ret, i;

        /* Adjust requested path mask to excluded varied off paths. */
        if (mask)
                mask &= sch->lpm;
        else
                mask = sch->lpm;

        chp_id_init(&chpid);
        for (i = 0; i < 8; i++) {
                if (!(mask & (0x80 >> i)))
                        continue;
                chpid.id = sch->schib.pmcw.chpid[i];
                ret = chsc_determine_fmt1_channel_path_desc(chpid, &desc);
                if (ret)
                        return ret;
                if (!desc.f)
                        return 0;
                if (!desc.r)
                        mdc = 1;
                mdc = mdc ? min(mdc, (int)desc.mdc) : desc.mdc;
        }

        return mdc;
}
EXPORT_SYMBOL(ccw_device_get_mdc);

/**
 * ccw_device_tm_intrg - perform interrogate function
 * @cdev: ccw device on which to perform the interrogate function
 *
 * Perform an interrogate function on the given ccw device. Return zero on
 * success, non-zero otherwise.
 */
int ccw_device_tm_intrg(struct ccw_device *cdev)
{
        struct subchannel *sch = to_subchannel(cdev->dev.parent);

        if (!sch->schib.pmcw.ena)
                return -EINVAL;
        if (cdev->private->state != DEV_STATE_ONLINE)
                return -EIO;
        if (!scsw_is_tm(&sch->schib.scsw) ||
            !(scsw_actl(&sch->schib.scsw) & SCSW_ACTL_START_PEND))
                return -EINVAL;
        return cio_tm_intrg(sch);
}
EXPORT_SYMBOL(ccw_device_tm_intrg);

// FIXME: these have to go:

int
_ccw_device_get_subchannel_number(struct ccw_device *cdev)
{
        return cdev->private->schid.sch_no;
}


MODULE_LICENSE("GPL");
EXPORT_SYMBOL(ccw_device_set_options_mask);
EXPORT_SYMBOL(ccw_device_set_options);
EXPORT_SYMBOL(ccw_device_clear_options);
EXPORT_SYMBOL(ccw_device_clear);
EXPORT_SYMBOL(ccw_device_halt);
EXPORT_SYMBOL(ccw_device_resume);
EXPORT_SYMBOL(ccw_device_start_timeout);
EXPORT_SYMBOL(ccw_device_start);
EXPORT_SYMBOL(ccw_device_start_timeout_key);
EXPORT_SYMBOL(ccw_device_start_key);
EXPORT_SYMBOL(ccw_device_get_ciw);
EXPORT_SYMBOL(ccw_device_get_path_mask);
EXPORT_SYMBOL(_ccw_device_get_subchannel_number);
EXPORT_SYMBOL_GPL(ccw_device_get_chp_desc);