From: Sebastian Ott <sebott@xxxxxxxxxxxxxxxxxx>
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: Sebastian Ott <sebott@xxxxxxxxxxxxxxxxxx>
Signed-off-by: Martin Schwidefsky <schwidefsky@xxxxxxxxxx>
---
drivers/s390/cio/Makefile | 4 +-
drivers/s390/cio/isc.c | 68 ++++++++++++++++++++++++++++++++++++++++++++++
include/asm-s390/isc.h | 6 ++++
3 files changed, 76 insertions(+), 2 deletions(-)
Index: quilt-2.6/drivers/s390/cio/isc.c
===================================================================
--- /dev/null
+++ quilt-2.6/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@xxxxxxxxxxxxxxxxxx>
+ */
+
+#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);
Index: quilt-2.6/drivers/s390/cio/Makefile
===================================================================
--- quilt-2.6.orig/drivers/s390/cio/Makefile
+++ quilt-2.6/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
Index: quilt-2.6/include/asm-s390/isc.h
===================================================================
--- quilt-2.6.orig/include/asm-s390/isc.h
+++ quilt-2.6/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 */
--
blue skies,
Martin.
"Reality continues to ruin my life." - Calvin.
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