[PATCH v4 9/9] clocksource/drivers/rockchip_timer: implement clocksource timer
heiko at sntech.de
Mon Jan 23 09:09:41 PST 2017
Am Dienstag, 29. November 2016, 19:14:52 CET schrieb Alexander Kochetkov:
> The clock supplying the arm-global-timer on the rk3188 is coming from the
> the cpu clock itself and thus changes its rate everytime cpufreq adjusts
> the cpu frequency making this timer unsuitable as a stable clocksource
> and sched clock.
> The rk3188, rk3288 and following socs share a separate timer block already
> handled by the rockchip-timer driver. Therefore adapt this driver to also
> be able to act as clocksource and sched clock on rk3188.
> In order to test clocksource you can run following commands and check
> how much time it take in real. On rk3188 it take about ~45 seconds.
> cpufreq-set -f 1.6GHZ
> date; sleep 60; date
> In order to use the patch you need to declare two timers in the dts
> file. The first timer will be initialized as clockevent provider
> and the second one as clocksource. The clockevent must be from
> alive subsystem as it used as backup for the local timers at sleep
> The patch does not break compatibility with older device tree files.
> The older device tree files contain only one timer. The timer
> will be initialized as clockevent, as expected.
> rk3288 (and probably anything newer) is irrelevant to this patch,
> as it has the arch timer interface. This patch may be usefull
> for Cortex-A9/A5 based parts.
> Signed-off-by: Alexander Kochetkov <al.kochet at gmail.com>
> @@ -120,13 +161,46 @@ static irqreturn_t rk_timer_interrupt(int irq, void
> *dev_id) return IRQ_HANDLED;
> +static cycle_t rk_timer_clocksource_read(struct clocksource *cs)
../drivers/clocksource/rockchip_timer.c:164:8: error: unknown type name ‘cycle_t’
static cycle_t rk_timer_clocksource_read(struct clocksource *cs)
looks like something in clocksources changed since november
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