• Marek Szyprowski's avatar
    clocksource/drivers/exynos_mct: Increase priority over ARM arch timer · 6282edb7
    Marek Szyprowski authored
    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: default avatarMarek Szyprowski <m.szyprowski@samsung.com>
    Reviewed-by: default avatarKrzysztof Kozlowski <krzk@kernel.org>
    Reviewed-by: default avatarChanwoo Choi <cw00.choi@samsung.com>
    Signed-off-by: default avatarDaniel Lezcano <daniel.lezcano@linaro.org>
    6282edb7
exynos_mct.c 15.9 KB