From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: From: John Stultz Subject: [RFC][PATCH 1/3] clocksource: s390: Convert s390 to use clocksource_register_khz Date: Mon, 23 Jan 2012 16:05:48 -0800 Message-Id: <1327363550-19952-2-git-send-email-john.stultz@linaro.org> In-Reply-To: <1327363550-19952-1-git-send-email-john.stultz@linaro.org> References: <1327363550-19952-1-git-send-email-john.stultz@linaro.org> Sender: linux-kernel-owner@vger.kernel.org List-Archive: List-Post: To: lkml Cc: John Stultz , Martin Schwidefsky , linux-s390@vger.kernel.org List-ID: Converts s390 TOD clock to use clocksource_register_khz The tod freq I calculated seems a bit fast. Need someone to double check me here. CC: Martin Schwidefsky CC: linux-s390@vger.kernel.org Signed-off-by: John Stultz --- arch/s390/kernel/time.c | 13 ++++++++++--- 1 files changed, 10 insertions(+), 3 deletions(-) diff --git a/arch/s390/kernel/time.c b/arch/s390/kernel/time.c index fa02f44..37e8ec5 100644 --- a/arch/s390/kernel/time.c +++ b/arch/s390/kernel/time.c @@ -207,8 +207,6 @@ static struct clocksource clocksource_tod = { .rating = 400, .read = read_tod_clock, .mask = -1ULL, - .mult = 1000, - .shift = 12, .flags = CLOCK_SOURCE_IS_CONTINUOUS, }; @@ -267,7 +265,16 @@ void __init time_init(void) if (register_external_interrupt(0x1406, timing_alert_interrupt)) panic("Couldn't request external interrupt 0x1406"); - if (clocksource_register(&clocksource_tod) != 0) + /* s390 TOD apparently runs at 4,096,000,000 cycs/sec + * XXX - Brute forced tod freq from: + * 2^shift/mult * NSEC_PER_SEC = cyc/sec + * 2^12 / 1000 * 1000000000 = cyc/sec + * 2^12 * 1000000 = cyc/sec + * 2^12 * 1000 = kcyc/sec + * 1000<<12 = kcyc/sec + * Could be totally wrong. -johnstul + */ + if (clocksource_register_khz(&clocksource_tod, (1000<<12) ) != 0) panic("Could not register TOD clock source"); /* Enable TOD clock interrupts on the boot cpu. */ -- 1.7.3.2.146.gca209