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    Subject[PATCH 4.4 050/101] clocksource: dw_apb_timer_of: Fix missing clockevent timers
    Date
    From: Serge Semin <Sergey.Semin@baikalelectronics.ru>

    [ Upstream commit 6d2e16a3181bafb77b535095c39ad1c8b9558c8c ]

    Commit 100214889973 ("clocksource: dw_apb_timer_of: use
    clocksource_of_init") replaced a publicly available driver
    initialization method with one called by the timer_probe() method
    available after CLKSRC_OF. In current implementation it traverses
    all the timers available in the system and calls their initialization
    methods if corresponding devices were either in dtb or in acpi. But
    if before the commit any number of available timers would be installed
    as clockevent and clocksource devices, after that there would be at most
    two. The rest are just ignored since default case branch doesn't do
    anything. I don't see a reason of such behaviour, neither the commit
    message explains it. Moreover this might be wrong if on some platforms
    these timers might be used for different purpose, as virtually CPU-local
    clockevent timers and as an independent broadcast timer. So in order
    to keep the compatibility with the platforms where the order of the
    timers detection has some meaning, lets add the secondly discovered
    timer to be of clocksource/sched_clock type, while the very first and
    the others would provide the clockevents service.

    Fixes: 100214889973 ("clocksource: dw_apb_timer_of: use clocksource_of_init")
    Signed-off-by: Serge Semin <Sergey.Semin@baikalelectronics.ru>
    Cc: Alexey Malahov <Alexey.Malahov@baikalelectronics.ru>
    Cc: Thomas Bogendoerfer <tsbogend@alpha.franken.de>
    Cc: Paul Burton <paulburton@kernel.org>
    Cc: Ralf Baechle <ralf@linux-mips.org>
    Cc: Alessandro Zummo <a.zummo@towertech.it>
    Cc: Alexandre Belloni <alexandre.belloni@bootlin.com>
    Cc: Arnd Bergmann <arnd@arndb.de>
    Cc: Rob Herring <robh+dt@kernel.org>
    Cc: linux-mips@vger.kernel.org
    Cc: linux-rtc@vger.kernel.org
    Cc: devicetree@vger.kernel.org
    Signed-off-by: Daniel Lezcano <daniel.lezcano@linaro.org>
    Link: https://lore.kernel.org/r/20200521204818.25436-7-Sergey.Semin@baikalelectronics.ru
    Signed-off-by: Sasha Levin <sashal@kernel.org>
    ---
    drivers/clocksource/dw_apb_timer_of.c | 6 ++----
    1 file changed, 2 insertions(+), 4 deletions(-)

    diff --git a/drivers/clocksource/dw_apb_timer_of.c b/drivers/clocksource/dw_apb_timer_of.c
    index a19a3f619cc7..99e5fd59964b 100644
    --- a/drivers/clocksource/dw_apb_timer_of.c
    +++ b/drivers/clocksource/dw_apb_timer_of.c
    @@ -134,16 +134,14 @@ static int num_called;
    static void __init dw_apb_timer_init(struct device_node *timer)
    {
    switch (num_called) {
    - case 0:
    - pr_debug("%s: found clockevent timer\n", __func__);
    - add_clockevent(timer);
    - break;
    case 1:
    pr_debug("%s: found clocksource timer\n", __func__);
    add_clocksource(timer);
    init_sched_clock();
    break;
    default:
    + pr_debug("%s: found clockevent timer\n", __func__);
    + add_clockevent(timer);
    break;
    }

    --
    2.25.1


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