[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: Sebastian Ott <sebott@linux.vnet.ibm.com> Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com> Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com>

[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: Sebastian Ott <sebott@linux.vnet.ibm.com> Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com> Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com>
Sebastian Ott · Heiko Carstens
1 parent da7c5af828
Showing 3 changed files with 76 additions and 2 deletions Side-by-side Diff
drivers/s390/cio/Makefile
drivers/s390/cio/isc.c
include/asm-s390/isc.h
@@ -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
+/*
+ * 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);
 #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
@@ -14,6 +16,10 @@
 #define CONSOLE_ISC 1			/* console I/O subchannel */
 /* 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 */
...	...	@@ -2,8 +2,8 @@
2	2	# Makefile for the S/390 common i/o drivers
3	3	#
4	4
5		-obj-y += airq.o blacklist.o chsc.o cio.o css.o chp.o idset.o scsw.o fcx.o \
6		- itcw.o
	5	+obj-y += airq.o blacklist.o chsc.o cio.o css.o chp.o idset.o isc.o scsw.o \
	6	+ fcx.o itcw.o
7	7	ccw_device-objs += device.o device_fsm.o device_ops.o
8	8	ccw_device-objs += device_id.o device_pgid.o device_status.o
9	9	obj-y += ccw_device.o cmf.o
	1	+/*
	2	+ * Functions for registration of I/O interruption subclasses on s390.
	3	+ *
	4	+ * Copyright IBM Corp. 2008
	5	+ * Authors: Sebastian Ott <sebott@linux.vnet.ibm.com>
	6	+ */
	7	+
	8	+#include <linux/spinlock.h>
	9	+#include <linux/module.h>
	10	+#include <asm/isc.h>
	11	+
	12	+static unsigned int isc_refs[MAX_ISC + 1];
	13	+static DEFINE_SPINLOCK(isc_ref_lock);
	14	+
	15	+
	16	+/**
	17	+ * isc_register - register an I/O interruption subclass.
	18	+ * @isc: I/O interruption subclass to register
	19	+ *
	20	+ * The number of users for @isc is increased. If this is the first user to
	21	+ * register @isc, the corresponding I/O interruption subclass mask is enabled.
	22	+ *
	23	+ * Context:
	24	+ * This function must not be called in interrupt context.
	25	+ */
	26	+void isc_register(unsigned int isc)
	27	+{
	28	+ if (isc > MAX_ISC) {
	29	+ WARN_ON(1);
	30	+ return;
	31	+ }
	32	+
	33	+ spin_lock(&isc_ref_lock);
	34	+ if (isc_refs[isc] == 0)
	35	+ ctl_set_bit(6, 31 - isc);
	36	+ isc_refs[isc]++;
	37	+ spin_unlock(&isc_ref_lock);
	38	+}
	39	+EXPORT_SYMBOL_GPL(isc_register);
	40	+
	41	+/**
	42	+ * isc_unregister - unregister an I/O interruption subclass.
	43	+ * @isc: I/O interruption subclass to unregister
	44	+ *
	45	+ * The number of users for @isc is decreased. If this is the last user to
	46	+ * unregister @isc, the corresponding I/O interruption subclass mask is
	47	+ * disabled.
	48	+ * Note: This function must not be called if isc_register() hasn't been called
	49	+ * before by the driver for @isc.
	50	+ *
	51	+ * Context:
	52	+ * This function must not be called in interrupt context.
	53	+ */
	54	+void isc_unregister(unsigned int isc)
	55	+{
	56	+ spin_lock(&isc_ref_lock);
	57	+ /* check for misuse */
	58	+ if (isc > MAX_ISC \|\| isc_refs[isc] == 0) {
	59	+ WARN_ON(1);
	60	+ goto out_unlock;
	61	+ }
	62	+ if (isc_refs[isc] == 1)
	63	+ ctl_clear_bit(6, 31 - isc);
	64	+ isc_refs[isc]--;
	65	+out_unlock:
	66	+ spin_unlock(&isc_ref_lock);
	67	+}
	68	+EXPORT_SYMBOL_GPL(isc_unregister);
1	1	#ifndef _ASM_S390_ISC_H
2	2	#define _ASM_S390_ISC_H
3	3
	4	+#include <linux/types.h>
	5	+
4	6	/*
5	7	* I/O interruption subclasses used by drivers.
6	8	* Please add all used iscs here so that it is possible to distribute
...	...	@@ -14,6 +16,10 @@
14	16	#define CONSOLE_ISC 1 /* console I/O subchannel */
15	17	/* Adapter interrupts. */
16	18	#define QDIO_AIRQ_ISC IO_SCH_ISC /* I/O subchannel in qdio mode */
	19	+
	20	+/* Functions for registration of I/O interruption subclasses */
	21	+void isc_register(unsigned int isc);
	22	+void isc_unregister(unsigned int isc);
17	23
18	24	#endif /* _ASM_S390_ISC_H */