linux/drivers/s390/cio/device_ops.c

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/*
* 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 <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;
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;
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;
}
/**
* 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 ||
cdev->private->state == DEV_STATE_CLEAR_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)
{
struct subchannel *sch;
unsigned int stctl;
int ending_status;
sch = to_subchannel(cdev->dev.parent);
/*
* 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;
}
/*
* Try to break the lock on a boxed device.
*/
int
ccw_device_stlck(struct ccw_device *cdev)
{
void *buf, *buf2;
unsigned long flags;
struct subchannel *sch;
int ret;
if (!cdev)
return -ENODEV;
if (cdev->drv && !cdev->private->options.force)
return -EINVAL;
sch = to_subchannel(cdev->dev.parent);
CIO_TRACE_EVENT(2, "stl lock");
CIO_TRACE_EVENT(2, dev_name(&cdev->dev));
buf = kmalloc(32*sizeof(char), GFP_DMA|GFP_KERNEL);
if (!buf)
return -ENOMEM;
buf2 = kmalloc(32*sizeof(char), GFP_DMA|GFP_KERNEL);
if (!buf2) {
kfree(buf);
return -ENOMEM;
}
spin_lock_irqsave(sch->lock, flags);
ret = cio_enable_subchannel(sch, (u32)(addr_t)sch);
if (ret)
goto out_unlock;
/*
* Setup ccw. We chain an unconditional reserve and a release so we
* only break the lock.
*/
cdev->private->iccws[0].cmd_code = CCW_CMD_STLCK;
cdev->private->iccws[0].cda = (__u32) __pa(buf);
cdev->private->iccws[0].count = 32;
cdev->private->iccws[0].flags = CCW_FLAG_CC;
cdev->private->iccws[1].cmd_code = CCW_CMD_RELEASE;
cdev->private->iccws[1].cda = (__u32) __pa(buf2);
cdev->private->iccws[1].count = 32;
cdev->private->iccws[1].flags = 0;
ret = cio_start(sch, cdev->private->iccws, 0);
if (ret) {
cio_disable_subchannel(sch); //FIXME: return code?
goto out_unlock;
}
cdev->private->irb.scsw.cmd.actl |= SCSW_ACTL_START_PEND;
spin_unlock_irqrestore(sch->lock, flags);
wait_event(cdev->private->wait_q,
cdev->private->irb.scsw.cmd.actl == 0);
spin_lock_irqsave(sch->lock, flags);
cio_disable_subchannel(sch); //FIXME: return code?
if ((cdev->private->irb.scsw.cmd.dstat !=
(DEV_STAT_CHN_END|DEV_STAT_DEV_END)) ||
(cdev->private->irb.scsw.cmd.cstat != 0))
ret = -EIO;
/* Clear irb. */
memset(&cdev->private->irb, 0, sizeof(struct irb));
out_unlock:
kfree(buf);
kfree(buf2);
spin_unlock_irqrestore(sch->lock, flags);
return ret;
}
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_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);