Contributors: 12
Author Tokens Token Proportion Commits Commit Proportion
Martin Schwidefsky 642 25.71% 5 11.36%
Sebastian Ott 558 22.35% 10 22.73%
Peter Oberparleiter 540 21.63% 11 25.00%
Cornelia Huck 388 15.54% 7 15.91%
Thomas Spatzier 106 4.25% 1 2.27%
Andrew Morton 92 3.68% 3 6.82%
Halil Pasic 76 3.04% 1 2.27%
Alexandra Winter 52 2.08% 1 2.27%
Peter Tiedemann 39 1.56% 1 2.27%
Greg Kroah-Hartman 2 0.08% 2 4.55%
Paul Gortmaker 1 0.04% 1 2.27%
Jan Höppner 1 0.04% 1 2.27%
Total 2497 44 


// SPDX-License-Identifier: GPL-1.0+
/*
 * Copyright IBM Corp. 2002, 2009
 *
 * Author(s): Martin Schwidefsky (schwidefsky@de.ibm.com)
 *	      Cornelia Huck (cornelia.huck@de.ibm.com)
 */
#include <linux/export.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 to be returned upon conclusion of csch
 *
 * 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_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).
 * The interruption handler will echo back the @intparm specified here, unless
 * another interruption parameter is specified by a subsequent invocation of
 * ccw_device_halt() or ccw_device_clear().
 * 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)
{
	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 = FAKE_CMD_IRB;
			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 exclude unusable paths. */
	if (lpm) {
		lpm &= sch->lpm;
		if (lpm == 0)
			return -EACCES;
	}
	ret = cio_start_key (sch, cpa, lpm, key);
	switch (ret) {
	case 0:
		cdev->private->intparm = intparm;
		if (expires)
			ccw_device_set_timeout(cdev, expires);
		break;
	case -EACCES:
	case -ENODEV:
		dev_fsm_event(cdev, DEV_EVENT_VERIFY);
		break;
	}
	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).
 * The interruption handler will echo back the @intparm specified here, unless
 * another interruption parameter is specified by a subsequent invocation of
 * ccw_device_halt() or ccw_device_clear().
 * 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)
{
	return ccw_device_start_timeout_key(cdev, cpa, intparm, lpm, key,
					    flags, 0);
}

/**
 * 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).
 * The interruption handler will echo back the @intparm specified here, unless
 * another interruption parameter is specified by a subsequent invocation of
 * ccw_device_halt() or ccw_device_clear().
 * 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).
 * The interruption handler will echo back the @intparm specified here, unless
 * another interruption parameter is specified by a subsequent invocation of
 * ccw_device_halt() or ccw_device_clear().
 * 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 to be returned upon conclusion of hsch
 *
 * ccw_device_halt() calls hsch on @cdev's subchannel.
 * The interruption handler will echo back the @intparm specified here, unless
 * another interruption parameter is specified by a subsequent invocation of
 * ccw_device_clear().
 * 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);
}

/**
 * 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->dma_area->senseid.ciw[ciw_cnt].ct == ct)
			return cdev->private->dma_area->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;
}

/**
 * ccw_device_get_chp_desc() - return newly allocated channel-path descriptor
 * @cdev: device to obtain the descriptor for
 * @chp_idx: index of the channel path
 *
 * On success return a newly allocated copy of the channel-path description
 * data associated with the given channel path. Return %NULL on error.
 */
struct channel_path_desc_fmt0 *ccw_device_get_chp_desc(struct ccw_device *cdev,
						       int chp_idx)
{
	struct subchannel *sch;
	struct chp_id chpid;

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

/**
 * ccw_device_get_util_str() - return newly allocated utility strings
 * @cdev: device to obtain the utility strings for
 * @chp_idx: index of the channel path
 *
 * On success return a newly allocated copy of the utility strings
 * associated with the given channel path. Return %NULL on error.
 */
u8 *ccw_device_get_util_str(struct ccw_device *cdev, int chp_idx)
{
	struct subchannel *sch = to_subchannel(cdev->dev.parent);
	struct channel_path *chp;
	struct chp_id chpid;
	u8 *util_str;

	chp_id_init(&chpid);
	chpid.id = sch->schib.pmcw.chpid[chp_idx];
	chp = chpid_to_chp(chpid);

	util_str = kmalloc(sizeof(chp->desc_fmt3.util_str), GFP_KERNEL);
	if (!util_str)
		return NULL;

	mutex_lock(&chp->lock);
	memcpy(util_str, chp->desc_fmt3.util_str, sizeof(chp->desc_fmt3.util_str));
	mutex_unlock(&chp->lock);

	return util_str;
}

/**
 * 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_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)
{
	struct subchannel *sch;
	int rc;

	sch = to_subchannel(cdev->dev.parent);
	if (!sch->schib.pmcw.ena)
		return -EINVAL;
	if (cdev->private->state == DEV_STATE_VERIFY) {
		/* Remember to fake irb when finished. */
		if (!cdev->private->flags.fake_irb) {
			cdev->private->flags.fake_irb = FAKE_TM_IRB;
			cdev->private->intparm = intparm;
			return 0;
		} else
			/* There's already a fake I/O around. */
			return -EBUSY;
	}
	if (cdev->private->state != DEV_STATE_ONLINE)
		return -EIO;
	/* Adjust requested path mask to exclude unusable paths. */
	if (lpm) {
		lpm &= sch->lpm;
		if (lpm == 0)
			return -EACCES;
	}
	rc = cio_tm_start_key(sch, tcw, lpm, key);
	if (rc == 0) {
		cdev->private->intparm = intparm;
		if (expires)
			ccw_device_set_timeout(cdev, expires);
	}
	return rc;
}
EXPORT_SYMBOL(ccw_device_tm_start_timeout_key);

/**
 * 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)
{
	return ccw_device_tm_start_timeout_key(cdev, tcw, intparm, lpm, key, 0);
}
EXPORT_SYMBOL(ccw_device_tm_start_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 value 0 indicates failure.
 */
int ccw_device_get_mdc(struct ccw_device *cdev, u8 mask)
{
	struct subchannel *sch = to_subchannel(cdev->dev.parent);
	struct channel_path *chp;
	struct chp_id chpid;
	int mdc = 0, 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];
		chp = chpid_to_chp(chpid);
		if (!chp)
			continue;

		mutex_lock(&chp->lock);
		if (!chp->desc_fmt1.f) {
			mutex_unlock(&chp->lock);
			return 0;
		}
		if (!chp->desc_fmt1.r)
			mdc = 1;
		mdc = mdc ? min_t(int, mdc, chp->desc_fmt1.mdc) :
			    chp->desc_fmt1.mdc;
		mutex_unlock(&chp->lock);
	}

	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);

/**
 * ccw_device_get_schid() - obtain a subchannel id
 * @cdev: device to obtain the id for
 * @schid: where to fill in the values
 */
void ccw_device_get_schid(struct ccw_device *cdev, struct subchannel_id *schid)
{
	struct subchannel *sch = to_subchannel(cdev->dev.parent);

	*schid = sch->schid;
}
EXPORT_SYMBOL_GPL(ccw_device_get_schid);

/**
 * ccw_device_pnso() - Perform Network-Subchannel Operation
 * @cdev:		device on which PNSO is performed
 * @pnso_area:		request and response block for the operation
 * @resume_token:	resume token for multiblock response
 * @cnc:		Boolean change-notification control
 *
 * pnso_area must be allocated by the caller with get_zeroed_page(GFP_KERNEL)
 *
 * Returns 0 on success.
 */
int ccw_device_pnso(struct ccw_device *cdev,
		    struct chsc_pnso_area *pnso_area,
		    struct chsc_pnso_resume_token resume_token,
		    int cnc)
{
	struct subchannel_id schid;

	ccw_device_get_schid(cdev, &schid);
	return chsc_pnso(schid, pnso_area, resume_token, cnc);
}
EXPORT_SYMBOL_GPL(ccw_device_pnso);

/*
 * Allocate zeroed dma coherent 31 bit addressable memory using
 * the subchannels dma pool. Maximal size of allocation supported
 * is PAGE_SIZE.
 */
void *ccw_device_dma_zalloc(struct ccw_device *cdev, size_t size)
{
	return cio_gp_dma_zalloc(cdev->private->dma_pool, &cdev->dev, size);
}
EXPORT_SYMBOL(ccw_device_dma_zalloc);

void ccw_device_dma_free(struct ccw_device *cdev, void *cpu_addr, size_t size)
{
	cio_gp_dma_free(cdev->private->dma_pool, cpu_addr, size);
}
EXPORT_SYMBOL(ccw_device_dma_free);

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_GPL(ccw_device_get_chp_desc);
EXPORT_SYMBOL_GPL(ccw_device_get_util_str);