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ARM: tegra: convert sched_clock() to use new infrastructure

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Convert tegra to use the new sched_clock() infrastructure for extending
32bit counters to full 64-bit nanoseconds.

Tested-by: Olof Johansson <olof@lixom.net>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
This commit is contained in:
Russell King 2010-12-15 21:49:42 +00:00
parent 5094b92f1c
commit e3f4c0ab91
2 changed files with 22 additions and 2 deletions
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1
arch/arm/Kconfig
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@ -570,6 +570,7 @@ config ARCH_TEGRA
select GENERIC_CLOCKEVENTS select GENERIC_CLOCKEVENTS
select GENERIC_GPIO select GENERIC_GPIO
select HAVE_CLK select HAVE_CLK
select HAVE_SCHED_CLOCK
select COMMON_CLKDEV select COMMON_CLKDEV
select ARCH_HAS_BARRIERS if CACHE_L2X0 select ARCH_HAS_BARRIERS if CACHE_L2X0
select ARCH_HAS_CPUFREQ select ARCH_HAS_CPUFREQ

23
arch/arm/mach-tegra/timer.c
View file

@ -26,10 +26,10 @@
#include <linux/clocksource.h> #include <linux/clocksource.h>
#include <linux/clk.h> #include <linux/clk.h>
#include <linux/io.h> #include <linux/io.h>
#include <linux/cnt32_to_63.h>
#include <asm/mach/time.h> #include <asm/mach/time.h>
#include <asm/localtimer.h> #include <asm/localtimer.h>
#include <asm/sched_clock.h>
#include <mach/iomap.h> #include <mach/iomap.h>
#include <mach/irqs.h> #include <mach/irqs.h>
@ -111,9 +111,25 @@ static struct clocksource tegra_clocksource = {
.flags = CLOCK_SOURCE_IS_CONTINUOUS, .flags = CLOCK_SOURCE_IS_CONTINUOUS,
}; };
static DEFINE_CLOCK_DATA(cd);
/*
* Constants generated by clocks_calc_mult_shift(m, s, 1MHz, NSEC_PER_SEC, 60).
* This gives a resolution of about 1us and a wrap period of about 1h11min.
*/
#define SC_MULT 4194304000u
#define SC_SHIFT 22
unsigned long long notrace sched_clock(void) unsigned long long notrace sched_clock(void)
{ {
return cnt32_to_63(timer_readl(TIMERUS_CNTR_1US)) * 1000; u32 cyc = timer_readl(TIMERUS_CNTR_1US);
return cyc_to_fixed_sched_clock(&cd, cyc, (u32)~0, SC_MULT, SC_SHIFT);
}
static void notrace tegra_update_sched_clock(void)
{
u32 cyc = timer_readl(TIMERUS_CNTR_1US);
update_sched_clock(&cd, cyc, (u32)~0);
} }
static irqreturn_t tegra_timer_interrupt(int irq, void *dev_id) static irqreturn_t tegra_timer_interrupt(int irq, void *dev_id)
@ -158,6 +174,9 @@ static void __init tegra_init_timer(void)
WARN(1, "Unknown clock rate"); WARN(1, "Unknown clock rate");
} }
init_fixed_sched_clock(&cd, tegra_update_sched_clock, 32,
1000000, SC_MULT, SC_SHIFT);
if (clocksource_register_hz(&tegra_clocksource, 1000000)) { if (clocksource_register_hz(&tegra_clocksource, 1000000)) {
printk(KERN_ERR "Failed to register clocksource\n"); printk(KERN_ERR "Failed to register clocksource\n");
BUG(); BUG();