From: Nicolai Stange <nicstange@gmail.com>
Date: Thu, 30 Mar 2017 20:04:58 +0000 (+0200)
Subject: x86/uv/time: Set ->min_delta_ticks and ->max_delta_ticks
X-Git-Tag: v4.12-rc1~157^2~7^2
X-Git-Url: https://git.karo-electronics.de/?a=commitdiff_plain;h=6fc46497a9fb283c4f8e8d04ae4f0bf3c0041f7e;p=karo-tx-linux.git

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>
---

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) {