From d54853ef8cb17296ac7bce9c77430fb7c80532d0 Mon Sep 17 00:00:00 2001 From: Martin Schwidefsky Date: Mon, 5 Feb 2007 21:18:19 +0100 Subject: [S390] ETR support. This patch adds support for clock synchronization to an external time reference (ETR). The external time reference sends an oscillator signal and a synchronization signal every 2^20 microseconds to keep the TOD clocks of all connected servers in sync. For availability two ETR units can be connected to a machine. If the clock deviates for more than the sync-check tolerance all cpus get a machine check that indicates that the clock is out of sync. For the lovely details how to get the clock back in sync see the code below. Signed-off-by: Martin Schwidefsky --- include/asm-s390/timex.h | 36 ++++++++++++++++++++++++++++++++++++ 1 file changed, 36 insertions(+) (limited to 'include/asm-s390/timex.h') diff --git a/include/asm-s390/timex.h b/include/asm-s390/timex.h index 9ee5d8013796..5cbd55cb40ce 100644 --- a/include/asm-s390/timex.h +++ b/include/asm-s390/timex.h @@ -11,6 +11,41 @@ #ifndef _ASM_S390_TIMEX_H #define _ASM_S390_TIMEX_H +/* Inline functions for clock register access. */ +static inline int set_clock(__u64 time) +{ + int cc; + + asm volatile( + " sck 0(%2)\n" + " ipm %0\n" + " srl %0,28\n" + : "=d" (cc) : "m" (time), "a" (&time) : "cc"); + return cc; +} + +static inline int store_clock(__u64 *time) +{ + int cc; + + asm volatile( + " stck 0(%2)\n" + " ipm %0\n" + " srl %0,28\n" + : "=d" (cc), "=m" (*time) : "a" (time) : "cc"); + return cc; +} + +static inline void set_clock_comparator(__u64 time) +{ + asm volatile("sckc 0(%1)" : : "m" (time), "a" (&time)); +} + +static inline void store_clock_comparator(__u64 *time) +{ + asm volatile("stckc 0(%1)" : "=m" (*time) : "a" (time)); +} + #define CLOCK_TICK_RATE 1193180 /* Underlying HZ */ typedef unsigned long long cycles_t; @@ -32,6 +67,7 @@ static inline cycles_t get_cycles(void) return (cycles_t) get_clock() >> 2; } +int get_sync_clock(unsigned long long *clock); void init_cpu_timer(void); #endif -- cgit v1.2.1