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authorRussell King <rmk+kernel@arm.linux.org.uk>2010-12-15 16:49:42 -0500
committerRussell King <rmk+kernel@arm.linux.org.uk>2010-12-22 17:44:47 -0500
commite3f4c0ab916334e861fc49eeb2673a8c13e978e7 (patch)
treeb3275eb4e32b4d4037dc67ad380dfcdacc20750c /arch/arm/mach-tegra/timer.c
parent5094b92f1c7d0f21c5d4411ba7415bac0684210f (diff)
ARM: tegra: convert sched_clock() to use new infrastructure
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>
Diffstat (limited to 'arch/arm/mach-tegra/timer.c')
-rw-r--r--arch/arm/mach-tegra/timer.c23
1 files changed, 21 insertions, 2 deletions
diff --git a/arch/arm/mach-tegra/timer.c b/arch/arm/mach-tegra/timer.c
index c52bd84652e5..7b8ad1f98f44 100644
--- a/arch/arm/mach-tegra/timer.c
+++ b/arch/arm/mach-tegra/timer.c
@@ -26,10 +26,10 @@
26#include <linux/clocksource.h> 26#include <linux/clocksource.h>
27#include <linux/clk.h> 27#include <linux/clk.h>
28#include <linux/io.h> 28#include <linux/io.h>
29#include <linux/cnt32_to_63.h>
30 29
31#include <asm/mach/time.h> 30#include <asm/mach/time.h>
32#include <asm/localtimer.h> 31#include <asm/localtimer.h>
32#include <asm/sched_clock.h>
33 33
34#include <mach/iomap.h> 34#include <mach/iomap.h>
35#include <mach/irqs.h> 35#include <mach/irqs.h>
@@ -111,9 +111,25 @@ static struct clocksource tegra_clocksource = {
111 .flags = CLOCK_SOURCE_IS_CONTINUOUS, 111 .flags = CLOCK_SOURCE_IS_CONTINUOUS,
112}; 112};
113 113
114static DEFINE_CLOCK_DATA(cd);
115
116/*
117 * Constants generated by clocks_calc_mult_shift(m, s, 1MHz, NSEC_PER_SEC, 60).
118 * This gives a resolution of about 1us and a wrap period of about 1h11min.
119 */
120#define SC_MULT 4194304000u
121#define SC_SHIFT 22
122
114unsigned long long notrace sched_clock(void) 123unsigned long long notrace sched_clock(void)
115{ 124{
116 return cnt32_to_63(timer_readl(TIMERUS_CNTR_1US)) * 1000; 125 u32 cyc = timer_readl(TIMERUS_CNTR_1US);
126 return cyc_to_fixed_sched_clock(&cd, cyc, (u32)~0, SC_MULT, SC_SHIFT);
127}
128
129static void notrace tegra_update_sched_clock(void)
130{
131 u32 cyc = timer_readl(TIMERUS_CNTR_1US);
132 update_sched_clock(&cd, cyc, (u32)~0);
117} 133}
118 134
119static irqreturn_t tegra_timer_interrupt(int irq, void *dev_id) 135static irqreturn_t tegra_timer_interrupt(int irq, void *dev_id)
@@ -158,6 +174,9 @@ static void __init tegra_init_timer(void)
158 WARN(1, "Unknown clock rate"); 174 WARN(1, "Unknown clock rate");
159 } 175 }
160 176
177 init_fixed_sched_clock(&cd, tegra_update_sched_clock, 32,
178 1000000, SC_MULT, SC_SHIFT);
179
161 if (clocksource_register_hz(&tegra_clocksource, 1000000)) { 180 if (clocksource_register_hz(&tegra_clocksource, 1000000)) {
162 printk(KERN_ERR "Failed to register clocksource\n"); 181 printk(KERN_ERR "Failed to register clocksource\n");
163 BUG(); 182 BUG();