lkml.org 
[lkml]   [2013]   [Jul]   [3]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
    Patch in this message
    /
    From
    Subject[PATCH] clocksource/cadence_ttc: Reuse clocksource as sched_clock
    Date
    Reuse the TTC clocksource timer as sched clock, too. Since only a single
    sched clock is supported in Linux, this feature optional and can be
    selected through Kconfig.

    Signed-off-by: Soren Brinkmann <soren.brinkmann@xilinx.com>
    ---
    drivers/clocksource/Kconfig | 7 +++++++
    drivers/clocksource/cadence_ttc_timer.c | 18 ++++++++++++++++++
    2 files changed, 25 insertions(+)

    diff --git a/drivers/clocksource/Kconfig b/drivers/clocksource/Kconfig
    index 5871933..8dda767 100644
    --- a/drivers/clocksource/Kconfig
    +++ b/drivers/clocksource/Kconfig
    @@ -36,6 +36,13 @@ config VT8500_TIMER
    config CADENCE_TTC_TIMER
    bool

    +config CADENCE_TTC_TIMER_SCHED_CLOCK
    + bool "Cadence TTC Sched Clock"
    + depends on CADENCE_TTC_TIMER
    + help
    + Use the clocksource timer provided by the TTC as
    + sched clock, also.
    +
    config CLKSRC_NOMADIK_MTU
    bool
    depends on (ARCH_NOMADIK || ARCH_U8500)
    diff --git a/drivers/clocksource/cadence_ttc_timer.c b/drivers/clocksource/cadence_ttc_timer.c
    index 4cbe28c..ef0f52b 100644
    --- a/drivers/clocksource/cadence_ttc_timer.c
    +++ b/drivers/clocksource/cadence_ttc_timer.c
    @@ -22,6 +22,7 @@
    #include <linux/of_irq.h>
    #include <linux/slab.h>
    #include <linux/clk-provider.h>
    +#include <asm/sched_clock.h>

    /*
    * This driver configures the 2 16-bit count-up timers as follows:
    @@ -95,6 +96,10 @@ struct ttc_timer_clockevent {
    #define to_ttc_timer_clkevent(x) \
    container_of(x, struct ttc_timer_clockevent, ce)

    +#ifdef CONFIG_CADENCE_TTC_TIMER_SCHED_CLOCK
    +static void __iomem *ttc_sched_clock_val_reg;
    +#endif
    +
    /**
    * ttc_set_interval - Set the timer interval value
    *
    @@ -156,6 +161,13 @@ static cycle_t __ttc_clocksource_read(struct clocksource *cs)
    TTC_COUNT_VAL_OFFSET);
    }

    +#ifdef CONFIG_CADENCE_TTC_TIMER_SCHED_CLOCK
    +static u32 notrace ttc_sched_clock_read(void)
    +{
    + return __raw_readl(ttc_sched_clock_val_reg);
    +}
    +#endif
    +
    /**
    * ttc_set_next_event - Sets the time interval for next event
    *
    @@ -297,6 +309,12 @@ static void __init ttc_setup_clocksource(struct clk *clk, void __iomem *base)
    kfree(ttccs);
    return;
    }
    +
    +#ifdef CONFIG_CADENCE_TTC_TIMER_SCHED_CLOCK
    + ttc_sched_clock_val_reg = base + TTC_COUNT_VAL_OFFSET;
    + setup_sched_clock(ttc_sched_clock_read, 16,
    + clk_get_rate(ttccs->ttc.clk) / PRESCALE);
    +#endif
    }

    static int ttc_rate_change_clockevent_cb(struct notifier_block *nb,
    --
    1.8.3.2


    \
     
     \ /
      Last update: 2013-07-04 00:21    [W:3.278 / U:0.016 seconds]
    ©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site