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Commit fcc6ab33 authored by Sebastian Ott's avatar Sebastian Ott Committed by Heiko Carstens
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[S390] cio: introduce isc_(un)register functions. 



This interface makes it easy for drivers to register usage of different
I/O interruption subclasses without needing to worry about possible
other users of the same isc.

Signed-off-by: default avatarSebastian Ott <sebott@linux.vnet.ibm.com>
Signed-off-by: default avatarMartin Schwidefsky <schwidefsky@de.ibm.com>
Signed-off-by: default avatarHeiko Carstens <heiko.carstens@de.ibm.com>
parent da7c5af8

drivers/s390/cio/Makefile

+2 −2
Original line number Diff line number Diff line
@@ -2,8 +2,8 @@ 
# Makefile for the S/390 common i/o drivers

#



obj-y += airq.o blacklist.o chsc.o cio.o css.o chp.o idset.o scsw.o fcx.o \

	 itcw.o

obj-y += airq.o blacklist.o chsc.o cio.o css.o chp.o idset.o isc.o scsw.o \

	fcx.o itcw.o

ccw_device-objs += device.o device_fsm.o device_ops.o

ccw_device-objs += device_id.o device_pgid.o device_status.o

obj-y += ccw_device.o cmf.o

drivers/s390/cio/isc.c

0 → 100644
+68 −0
Original line number Diff line number Diff line 
/*

 * Functions for registration of I/O interruption subclasses on s390.

 *

 * Copyright IBM Corp. 2008

 * Authors: Sebastian Ott <sebott@linux.vnet.ibm.com>

 */



#include <linux/spinlock.h>

#include <linux/module.h>

#include <asm/isc.h>



static unsigned int isc_refs[MAX_ISC + 1];

static DEFINE_SPINLOCK(isc_ref_lock);





/**

 * isc_register - register an I/O interruption subclass.

 * @isc: I/O interruption subclass to register

 *

 * The number of users for @isc is increased. If this is the first user to

 * register @isc, the corresponding I/O interruption subclass mask is enabled.

 *

 * Context:

 *   This function must not be called in interrupt context.

 */

void isc_register(unsigned int isc)

{

	if (isc > MAX_ISC) {

		WARN_ON(1);

		return;

	}



	spin_lock(&isc_ref_lock);

	if (isc_refs[isc] == 0)

		ctl_set_bit(6, 31 - isc);

	isc_refs[isc]++;

	spin_unlock(&isc_ref_lock);

}

EXPORT_SYMBOL_GPL(isc_register);



/**

 * isc_unregister - unregister an I/O interruption subclass.

 * @isc: I/O interruption subclass to unregister

 *

 * The number of users for @isc is decreased. If this is the last user to

 * unregister @isc, the corresponding I/O interruption subclass mask is

 * disabled.

 * Note: This function must not be called if isc_register() hasn't been called

 * before by the driver for @isc.

 *

 * Context:

 *   This function must not be called in interrupt context.

 */

void isc_unregister(unsigned int isc)

{

	spin_lock(&isc_ref_lock);

	/* check for misuse */

	if (isc > MAX_ISC || isc_refs[isc] == 0) {

		WARN_ON(1);

		goto out_unlock;

	}

	if (isc_refs[isc] == 1)

		ctl_clear_bit(6, 31 - isc);

	isc_refs[isc]--;

out_unlock:

	spin_unlock(&isc_ref_lock);

}

EXPORT_SYMBOL_GPL(isc_unregister);

include/asm-s390/isc.h

+6 −0
Original line number Diff line number Diff line 
#ifndef _ASM_S390_ISC_H

#define _ASM_S390_ISC_H



#include <linux/types.h>



/*

 * I/O interruption subclasses used by drivers.

 * Please add all used iscs here so that it is possible to distribute
@@ -15,4 +17,8 @@ 
/* Adapter interrupts. */

#define QDIO_AIRQ_ISC IO_SCH_ISC	/* I/O subchannel in qdio mode */



/* Functions for registration of I/O interruption subclasses */

void isc_register(unsigned int isc);

void isc_unregister(unsigned int isc);



#endif /* _ASM_S390_ISC_H */