diff options
Diffstat (limited to 'arch/arm/plat-nomadik')
| -rw-r--r-- | arch/arm/plat-nomadik/Kconfig | 1 | ||||
| -rw-r--r-- | arch/arm/plat-nomadik/timer.c | 76 |
2 files changed, 10 insertions, 67 deletions
diff --git a/arch/arm/plat-nomadik/Kconfig b/arch/arm/plat-nomadik/Kconfig index 5da3f97c537..187f4e84bb2 100644 --- a/arch/arm/plat-nomadik/Kconfig +++ b/arch/arm/plat-nomadik/Kconfig @@ -14,6 +14,7 @@ if PLAT_NOMADIK config HAS_MTU bool + select HAVE_SCHED_CLOCK help Support for Multi Timer Unit. MTU provides access to multiple interrupt generating programmable diff --git a/arch/arm/plat-nomadik/timer.c b/arch/arm/plat-nomadik/timer.c index c3b8a2246b9..41723402006 100644 --- a/arch/arm/plat-nomadik/timer.c +++ b/arch/arm/plat-nomadik/timer.c @@ -17,10 +17,9 @@ #include <linux/clk.h> #include <linux/jiffies.h> #include <linux/err.h> -#include <linux/cnt32_to_63.h> -#include <linux/timer.h> #include <linux/sched.h> #include <asm/mach/time.h> +#include <asm/sched_clock.h> #include <plat/mtu.h> @@ -53,81 +52,24 @@ static struct clocksource nmdk_clksrc = { * Override the global weak sched_clock symbol with this * local implementation which uses the clocksource to get some * better resolution when scheduling the kernel. - * - * Because the hardware timer period may be quite short - * (32.3 secs on the 133 MHz MTU timer selection on ux500) - * and because cnt32_to_63() needs to be called at least once per - * half period to work properly, a kernel keepwarm() timer is set up - * to ensure this requirement is always met. - * - * Also the sched_clock timer will wrap around at some point, - * here we set it to run continously for a year. */ -#define SCHED_CLOCK_MIN_WRAP 3600*24*365 -static struct timer_list cnt32_to_63_keepwarm_timer; -static u32 sched_mult; -static u32 sched_shift; +static DEFINE_CLOCK_DATA(cd); unsigned long long notrace sched_clock(void) { - u64 cycles; + u32 cyc; if (unlikely(!mtu_base)) return 0; - cycles = cnt32_to_63(-readl(mtu_base + MTU_VAL(0))); - /* - * sched_mult is guaranteed to be even so will - * shift out bit 63 - */ - return (cycles * sched_mult) >> sched_shift; + cyc = -readl(mtu_base + MTU_VAL(0)); + return cyc_to_sched_clock(&cd, cyc, (u32)~0); } -/* Just kick sched_clock every so often */ -static void cnt32_to_63_keepwarm(unsigned long data) +static void notrace nomadik_update_sched_clock(void) { - mod_timer(&cnt32_to_63_keepwarm_timer, round_jiffies(jiffies + data)); - (void) sched_clock(); -} - -/* - * Set up a timer to keep sched_clock():s 32_to_63 algorithm warm - * once in half a 32bit timer wrap interval. - */ -static void __init nmdk_sched_clock_init(unsigned long rate) -{ - u32 v; - unsigned long delta; - u64 days; - - /* Find the apropriate mult and shift factors */ - clocks_calc_mult_shift(&sched_mult, &sched_shift, - rate, NSEC_PER_SEC, SCHED_CLOCK_MIN_WRAP); - /* We need to multiply by an even number to get rid of bit 63 */ - if (sched_mult & 1) - sched_mult++; - - /* Let's see what we get, take max counter and scale it */ - days = (0xFFFFFFFFFFFFFFFFLLU * sched_mult) >> sched_shift; - do_div(days, NSEC_PER_SEC); - do_div(days, (3600*24)); - - pr_info("sched_clock: using %d bits @ %lu Hz wrap in %lu days\n", - (64 - sched_shift), rate, (unsigned long) days); - - /* - * Program a timer to kick us at half 32bit wraparound - * Formula: seconds per wrap = (2^32) / f - */ - v = 0xFFFFFFFFUL / rate; - /* We want half of the wrap time to keep cnt32_to_63 warm */ - v /= 2; - pr_debug("sched_clock: prescaled timer rate: %lu Hz, " - "initialize keepwarm timer every %d seconds\n", rate, v); - /* Convert seconds to jiffies */ - delta = msecs_to_jiffies(v*1000); - setup_timer(&cnt32_to_63_keepwarm_timer, cnt32_to_63_keepwarm, delta); - mod_timer(&cnt32_to_63_keepwarm_timer, round_jiffies(jiffies + delta)); + u32 cyc = -readl(mtu_base + MTU_VAL(0)); + update_sched_clock(&cd, cyc, (u32)~0); } /* Clockevent device: use one-shot mode */ @@ -237,7 +179,7 @@ void __init nmdk_timer_init(void) pr_err("timer: failed to initialize clock source %s\n", nmdk_clksrc.name); - nmdk_sched_clock_init(rate); + init_sched_clock(&cd, nomadik_update_sched_clock, 32, rate); /* Timer 1 is used for events */ |