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 --- arch/s390/kernel/s390_ext.c | 8 +++----- 1 file changed, 3 insertions(+), 5 deletions(-) (limited to 'arch/s390/kernel/s390_ext.c') diff --git a/arch/s390/kernel/s390_ext.c b/arch/s390/kernel/s390_ext.c index bc5beaa8f98..acf93dba772 100644 --- a/arch/s390/kernel/s390_ext.c +++ b/arch/s390/kernel/s390_ext.c @@ -125,14 +125,12 @@ void do_extint(struct pt_regs *regs, unsigned short code) * Make sure that the i/o interrupt did not "overtake" * the last HZ timer interrupt. */ - account_ticks(); + account_ticks(S390_lowcore.int_clock); kstat_cpu(smp_processor_id()).irqs[EXTERNAL_INTERRUPT]++; index = ext_hash(code); for (p = ext_int_hash[index]; p; p = p->next) { - if (likely(p->code == code)) { - if (likely(p->handler)) - p->handler(code); - } + if (likely(p->code == code)) + p->handler(code); } irq_exit(); set_irq_regs(old_regs); -- cgit v1.2.3