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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 <mingo@redhat.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Daniel Lezcano <daniel.lezcano@linaro.org>
Cc: Richard Cochran <richardcochran@gmail.com>
Cc: Prarit Bhargava <prarit@redhat.com>
Cc: Stephen Boyd <sboyd@codeaurora.org>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: x86@kernel.org
Cc: Mike Travis <travis@sgi.com>
Cc: Dimitri Sivanich <sivanich@sgi.com>
Signed-off-by: Nicolai Stange <nicstange@gmail.com>
Signed-off-by: John Stultz <john.stultz@linaro.org>
hifive-unleashed-5.1
Nicolai Stange 2017-03-30 22:04:58 +02:00 committed by John Stultz
parent 16c125b6c2
commit 6fc46497a9
1 changed files with 2 additions and 0 deletions
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2
arch/x86/platform/uv/uv_time.c
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@ -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) {