linux-kernel - [PATCH v3 05/13] ARM: dts: rockchip: disable arm-global-timer for rk3188

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Message-Id: <1480427118-5126-6-git-send-email-al.kochet@gmail.com>
Date:   Tue, 29 Nov 2016 16:45:10 +0300
From:   Alexander Kochetkov <al.kochet@...il.com>
To:     linux-kernel@...r.kernel.org, devicetree@...r.kernel.org,
        linux-arm-kernel@...ts.infradead.org,
        linux-rockchip@...ts.infradead.org
Cc:     Thomas Gleixner <tglx@...utronix.de>,
        Heiko Stuebner <heiko@...ech.de>,
        Mark Rutland <mark.rutland@....com>,
        Rob Herring <robh+dt@...nel.org>,
        Russell King <linux@...linux.org.uk>,
        Caesar Wang <wxt@...k-chips.com>,
        Huang Tao <huangtao@...k-chips.com>,
        Daniel Lezcano <daniel.lezcano@...aro.org>,
        Alexander Kochetkov <al.kochet@...il.com>
Subject: [PATCH v3 05/13] ARM: dts: rockchip: disable arm-global-timer for rk3188

arm-global-timer can provide clockevents, clocksource and shed_clock. But
on rk3188 platform it provide only clocksource and shed_clock. clockevents
from  arm-global-timer is not used by kernel because there is another
clockevent provider with higher rating (smp-twd).

My commit from the series implement clocksource and shed_clock using
rockchip_timer. But sched clock from rk_timer is not selected by kernel
due to lower frequency than arm-global-timer, and clocksource from
rk_timer is not selected by kernel due to lower rating than
arm-global-timer. And I don't want to increase clocksource rating
because ratings greater than 300 used for high frequency clocksources.

clocksource and shed_clock is quite unstable, because their rate depends
on cpu frequency. So disable arm-global-timer and use clocksource and
sched_clock from rockchip_timer.

Signed-off-by: Alexander Kochetkov <al.kochet@...il.com>
---
 arch/arm/boot/dts/rk3188.dtsi |    1 +
 1 file changed, 1 insertion(+)

diff --git a/arch/arm/boot/dts/rk3188.dtsi b/arch/arm/boot/dts/rk3188.dtsi
index 0dc52fe..44da3d42 100644
--- a/arch/arm/boot/dts/rk3188.dtsi
+++ b/arch/arm/boot/dts/rk3188.dtsi
@@ -546,6 +546,7 @@

 &global_timer {
 	interrupts = <GIC_PPI 11 0xf04>;
+	status = "disabled";
 };

 &local_timer {
-- 
1.7.9.5