From 6fc46497a9fb283c4f8e8d04ae4f0bf3c0041f7e Mon Sep 17 00:00:00 2001 From: Nicolai Stange Date: Thu, 30 Mar 2017 22:04:58 +0200 Subject: [PATCH] x86/uv/time: Set ->min_delta_ticks and ->max_delta_ticks In preparation for making the clockevents core NTP correction aware, all clockevent device drivers must set ->min_delta_ticks and ->max_delta_ticks rather than ->min_delta_ns and ->max_delta_ns: a clockevent device's rate is going to change dynamically and thus, the ratio of ns to ticks ceases to stay invariant. Currently, the x86's uv rtc clockevent device is initialized as follows: clock_event_device_uv.min_delta_ns = NSEC_PER_SEC / sn_rtc_cycles_per_second; clock_event_device_uv.max_delta_ns = clocksource_uv.mask * (NSEC_PER_SEC / sn_rtc_cycles_per_second); This translates to a ->min_delta_ticks value of 1 and a ->max_delta_ticks value of clocksource_uv.mask. Initialize ->min_delta_ticks and ->max_delta_ticks with these values respectively. This patch alone doesn't introduce any change in functionality as the clockevents core still looks exclusively at the (untouched) ->min_delta_ns and ->max_delta_ns. As soon as this has changed, a followup patch will purge the initialization of ->min_delta_ns and ->max_delta_ns from this driver. Cc: Ingo Molnar Cc: Thomas Gleixner Cc: Daniel Lezcano Cc: Richard Cochran Cc: Prarit Bhargava Cc: Stephen Boyd Cc: "H. Peter Anvin" Cc: x86@kernel.org Cc: Mike Travis Cc: Dimitri Sivanich Signed-off-by: Nicolai Stange Signed-off-by: John Stultz --- arch/x86/platform/uv/uv_time.c | 2 ++ 1 file changed, 2 insertions(+) diff --git a/arch/x86/platform/uv/uv_time.c b/arch/x86/platform/uv/uv_time.c index 2ee7632d4916..b082d71b08ee 100644 --- a/arch/x86/platform/uv/uv_time.c +++ b/arch/x86/platform/uv/uv_time.c @@ -390,9 +390,11 @@ static __init int uv_rtc_setup_clock(void) clock_event_device_uv.min_delta_ns = NSEC_PER_SEC / sn_rtc_cycles_per_second; + clock_event_device_uv.min_delta_ticks = 1; clock_event_device_uv.max_delta_ns = clocksource_uv.mask * (NSEC_PER_SEC / sn_rtc_cycles_per_second); + clock_event_device_uv.max_delta_ticks = clocksource_uv.mask; rc = schedule_on_each_cpu(uv_rtc_register_clockevents); if (rc) { -- 2.39.5