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From: Nicolai Stange <nicstange@gmail.com>
To: Mark Salter <msalter@redhat.com>, Aurelien Jacquiot <a-jacquiot@ti.com>
Cc: John Stultz <john.stultz@linaro.org>,
	linux-kernel@vger.kernel.org,
	Nicolai Stange <nicstange@gmail.com>,
	linux-c6x-dev@linux-c6x.org
Subject: [PATCH] c6x/timer64: set ->min_delta_ticks and ->max_delta_ticks
Date: Thu, 30 Mar 2017 21:42:20 +0200	[thread overview]
Message-ID: <20170330194220.6849-1-nicstange@gmail.com> (raw)
In-Reply-To: <20170326134403.16226-1-nicstange@gmail.com>

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.

Make the c6x arch's clockevent driver initialize these fields properly.

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.

Signed-off-by: Nicolai Stange <nicstange@gmail.com>
---

Notes:
    This prerequisite patch is part of a larger effort to feed NTP
    corrections into the clockevent devices' frequencies and thus
    avoiding their notion of time to diverge from the system's
    one. If you're interested, the current state of the whole series
    can be found at [1].
    
    If you haven't got any objections and these prerequisites get
    merged by 4.12 everywhere, I'll proceed with the remainder of
    this series in 4.13.
    
    Applicable to next-20170324 as well as to John' Stultz tree [2].
    
    [1]
      git://nicst.de/linux.git cev-freq-adj.v10.fortglx-4.12-time
      https://nicst.de/git/?p=linux.git;a=shortlog;h=refs/heads/cev-freq-adj.v10.fortglx-4.12-time
    
    [2]
      https://git.linaro.org/people/john.stultz/linux.git fortglx/4.12/time

 arch/c6x/platforms/timer64.c | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/arch/c6x/platforms/timer64.c b/arch/c6x/platforms/timer64.c
index c19901e5f055..0bd0452ded80 100644
--- a/arch/c6x/platforms/timer64.c
+++ b/arch/c6x/platforms/timer64.c
@@ -234,7 +234,9 @@ void __init timer64_init(void)
 	clockevents_calc_mult_shift(cd, c6x_core_freq / TIMER_DIVISOR, 5);
 
 	cd->max_delta_ns	= clockevent_delta2ns(0x7fffffff, cd);
+	cd->max_delta_ticks	= 0x7fffffff;
 	cd->min_delta_ns	= clockevent_delta2ns(250, cd);
+	cd->min_delta_ticks	= 250;
 
 	cd->cpumask		= cpumask_of(smp_processor_id());
 
-- 
2.12.0

  parent reply	other threads:[~2017-03-30 19:42 UTC|newest]

Thread overview: 54+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2017-03-26 13:44 [PATCH] x86/apic/timer: set ->min_delta_ticks and ->max_delta_ticks Nicolai Stange
2017-03-30 19:39 ` [PATCH] avr32/time: " Nicolai Stange
2017-04-03  6:42   ` Hans-Christian Noren Egtvedt
2017-03-30 19:41 ` [PATCH] blackfin: time-ts: " Nicolai Stange
2017-03-30 19:42 ` Nicolai Stange [this message]
2017-03-30 19:43 ` [PATCH] hexagon/time: " Nicolai Stange
2017-04-03 15:49   ` Richard Kuo
2017-03-30 19:44 ` [PATCH] m68k/coldfire/pit: " Nicolai Stange
2017-03-30 19:44   ` Nicolai Stange
2017-03-31  1:10   ` Greg Ungerer
2017-03-31  1:10   ` Greg Ungerer
2017-03-30 19:45 ` [PATCH] microblaze/timer: " Nicolai Stange
2017-04-07 13:14   ` Daniel Lezcano
2017-04-16  2:47     ` Nicolai Stange
2017-04-16  9:46       ` Daniel Lezcano
2017-05-29  9:03   ` Michal Simek
2017-03-30 19:47 ` [PATCH] MIPS: clockevent drivers: " Nicolai Stange
2017-04-12 20:10   ` Ralf Baechle
2017-03-30 19:48 ` [PATCH] mn10300/cevt-mn10300: " Nicolai Stange
2017-03-30 19:53 ` [PATCH] powerpc/time: " Nicolai Stange
2017-03-31  3:03   ` Michael Ellerman
2017-03-30 19:54 ` [PATCH] s390/time: " Nicolai Stange
2017-03-30 19:55 ` [PATCH] score/time: " Nicolai Stange
2017-03-30 19:56 ` [PATCH] sparc/time: " Nicolai Stange
2017-03-30 19:56   ` Nicolai Stange
2017-04-01 19:18   ` David Miller
2017-04-01 19:18     ` David Miller
2017-03-30 19:57 ` [PATCH] tile/time: " Nicolai Stange
2017-03-30 19:59 ` [PATCH] um/time: " Nicolai Stange
2017-03-30 20:01 ` [PATCH] unicore32/time: " Nicolai Stange
2017-03-31  1:59   ` Xuetao Guan
2017-03-30 20:03 ` [PATCH] x86/lguest/timer: " Nicolai Stange
2017-04-02  1:35   ` Rusty Russell
2017-03-30 20:04 ` [PATCH] x86/uv/time: " Nicolai Stange
2017-03-30 20:06 ` [PATCH] x86/xen/time: " Nicolai Stange
2017-03-30 20:06 ` Nicolai Stange
2017-03-30 22:59   ` Boris Ostrovsky
2017-03-30 22:59   ` Boris Ostrovsky
2017-04-06  9:11   ` Juergen Gross
2017-04-06  9:11   ` Juergen Gross
2017-04-11  5:09   ` Juergen Gross
2017-04-11  5:09   ` Juergen Gross
2017-03-30 20:07 ` [PATCH] clockevents/drivers/dw_apb: " Nicolai Stange
2017-04-07 13:20   ` Daniel Lezcano
2017-03-30 20:08 ` [PATCH] clockevents/drivers/metag: " Nicolai Stange
2017-04-07 13:20   ` Daniel Lezcano
2017-03-30 20:08 ` [PATCH] x86/numachip timer: " Nicolai Stange
2017-04-07 13:21   ` Daniel Lezcano
2017-03-30 20:09 ` [PATCH] clockevents/drivers/sh_cmt: " Nicolai Stange
2017-04-07 13:22   ` Daniel Lezcano
2017-03-30 20:10 ` [PATCH] clockevents/drivers/atlas7: " Nicolai Stange
2017-03-30 20:10   ` Nicolai Stange
2017-04-07 13:23   ` Daniel Lezcano
2017-04-07 13:23     ` Daniel Lezcano

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