s390/vtimer: rework virtual timer interface

The current virtual timer interface is inherently per-cpu and hard to
use. The sole user of the interface is appldata which uses it to execute
a function after a specific amount of cputime has been used over all cpus.

Rework the virtual timer interface to hook into the cputime accounting.
This makes the interface independent from the CPU timer interrupts, and
makes the virtual timers global as opposed to per-cpu.
Overall the code is greatly simplified. The downside is that the accuracy
is not as good as the original implementation, but it is still good enough
for appldata.

Reviewed-by: Jan Glauber <jang@linux.vnet.ibm.com>
Reviewed-by: Heiko Carstens <heiko.carstens@de.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>

1 files changed, 33 insertions, 0 deletions

diff --git a/arch/s390/include/asm/vtimer.h b/arch/s390/include/asm/vtimer.h
new file mode 100644
index 00000000000..bfe25d513ad
--- /dev/null
+++ b/arch/s390/include/asm/vtimer.h
@@ -0,0 +1,33 @@
+/*
+ *  Copyright IBM Corp. 2003, 2012
+ *  Virtual CPU timer
+ *
+ *  Author(s): Jan Glauber <jan.glauber@de.ibm.com>
+ */
+
+#ifndef _ASM_S390_TIMER_H
+#define _ASM_S390_TIMER_H
+
+#define VTIMER_MAX_SLICE (0x7fffffffffffffffULL)
+
+struct vtimer_list {
+	struct list_head entry;
+	u64 expires;
+	u64 interval;
+	void (*function)(unsigned long);
+	unsigned long data;
+};
+
+extern void init_virt_timer(struct vtimer_list *timer);
+extern void add_virt_timer(struct vtimer_list *timer);
+extern void add_virt_timer_periodic(struct vtimer_list *timer);
+extern int mod_virt_timer(struct vtimer_list *timer, u64 expires);
+extern int mod_virt_timer_periodic(struct vtimer_list *timer, u64 expires);
+extern int del_virt_timer(struct vtimer_list *timer);
+
+extern void init_cpu_vtimer(void);
+extern void vtime_init(void);
+
+extern void vtime_stop_cpu(void);
+
+#endif /* _ASM_S390_TIMER_H */