]> git.proxmox.com Git - mirror_ubuntu-bionic-kernel.git/commit
clocksource/drivers/exynos_mct: Increase priority over ARM arch timer
authorMarek Szyprowski <m.szyprowski@samsung.com>
Thu, 30 May 2019 10:50:43 +0000 (12:50 +0200)
committerKleber Sacilotto de Souza <kleber.souza@canonical.com>
Wed, 14 Aug 2019 09:18:49 +0000 (11:18 +0200)
commitdb0d06e535619a270f3fa8750cf5becbeda2836c
treed1d76ff387e87abd8b4f1b4c8473a7eeb48c5b0f
parente442efba04b6963ee74b238498780a50e12c9c97
clocksource/drivers/exynos_mct: Increase priority over ARM arch timer

BugLink: https://bugs.launchpad.net/bugs/1839036
[ Upstream commit 6282edb72bed5324352522d732080d4c1b9dfed6 ]

Exynos SoCs based on CA7/CA15 have 2 timer interfaces: custom Exynos MCT
(Multi Core Timer) and standard ARM Architected Timers.

There are use cases, where both timer interfaces are used simultanously.
One of such examples is using Exynos MCT for the main system timer and
ARM Architected Timers for the KVM and virtualized guests (KVM requires
arch timers).

Exynos Multi-Core Timer driver (exynos_mct) must be however started
before ARM Architected Timers (arch_timer), because they both share some
common hardware blocks (global system counter) and turning on MCT is
needed to get ARM Architected Timer working properly.

To ensure selecting Exynos MCT as the main system timer, increase MCT
timer rating. To ensure proper starting order of both timers during
suspend/resume cycle, increase MCT hotplug priority over ARM Archictected
Timers.

Signed-off-by: Marek Szyprowski <m.szyprowski@samsung.com>
Reviewed-by: Krzysztof Kozlowski <krzk@kernel.org>
Reviewed-by: Chanwoo Choi <cw00.choi@samsung.com>
Signed-off-by: Daniel Lezcano <daniel.lezcano@linaro.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
Signed-off-by: Kamal Mostafa <kamal@canonical.com>
Signed-off-by: Khalid Elmously <khalid.elmously@canonical.com>
drivers/clocksource/exynos_mct.c
include/linux/cpuhotplug.h