diff options
| -rw-r--r-- | drivers/s390/cio/Makefile | 4 | ||||
| -rw-r--r-- | drivers/s390/cio/isc.c | 68 | ||||
| -rw-r--r-- | include/asm-s390/isc.h | 6 |
3 files changed, 76 insertions, 2 deletions
diff --git a/drivers/s390/cio/Makefile b/drivers/s390/cio/Makefile index e199c927b7aa..6735ebb3c988 100644 --- a/drivers/s390/cio/Makefile +++ b/drivers/s390/cio/Makefile @@ -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 diff --git a/drivers/s390/cio/isc.c b/drivers/s390/cio/isc.c new file mode 100644 index 000000000000..c592087be0f1 --- /dev/null +++ b/drivers/s390/cio/isc.c @@ -0,0 +1,68 @@ +/* + * 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); diff --git a/include/asm-s390/isc.h b/include/asm-s390/isc.h index 533a1372234a..fe56f7b445ea 100644 --- a/include/asm-s390/isc.h +++ b/include/asm-s390/isc.h @@ -1,6 +1,8 @@ #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 */ |