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

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

Acked-by: Nicolas Pitre <nico@fluxnic.net>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
This commit is contained in:
Russell King 2010-12-15 21:55:06 +00:00
parent dc548fbbd2
commit f06a162462
2 changed files with 10 additions and 35 deletions
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1
arch/arm/Kconfig
View file

@ -997,6 +997,7 @@ config PLAT_IOP
config PLAT_ORION config PLAT_ORION
bool bool
select HAVE_SCHED_CLOCK
config PLAT_PXA config PLAT_PXA
bool bool

44
arch/arm/plat-orion/time.c
View file

@ -13,11 +13,11 @@
#include <linux/kernel.h> #include <linux/kernel.h>
#include <linux/sched.h> #include <linux/sched.h>
#include <linux/cnt32_to_63.h>
#include <linux/timer.h> #include <linux/timer.h>
#include <linux/clockchips.h> #include <linux/clockchips.h>
#include <linux/interrupt.h> #include <linux/interrupt.h>
#include <linux/irq.h> #include <linux/irq.h>
#include <asm/sched_clock.h>
#include <asm/mach/time.h> #include <asm/mach/time.h>
#include <mach/bridge-regs.h> #include <mach/bridge-regs.h>
#include <mach/hardware.h> #include <mach/hardware.h>
@ -44,52 +44,26 @@ static u32 ticks_per_jiffy;
/* /*
* Orion's sched_clock implementation. It has a resolution of * Orion's sched_clock implementation. It has a resolution of
* at least 7.5ns (133MHz TCLK) and a maximum value of 834 days. * at least 7.5ns (133MHz TCLK).
*
* Because the hardware timer period is quite short (21 secs if
* 200MHz TCLK) and because cnt32_to_63() needs to be called at
* least once per half period to work properly, a kernel timer is
* set up to ensure this requirement is always met.
*/ */
#define TCLK2NS_SCALE_FACTOR 8 static DEFINE_CLOCK_DATA(cd);
static unsigned long tclk2ns_scale;
unsigned long long notrace sched_clock(void) unsigned long long notrace sched_clock(void)
{ {
unsigned long long v = cnt32_to_63(0xffffffff - readl(TIMER0_VAL)); u32 cyc = 0xffffffff - readl(TIMER0_VAL);
return (v * tclk2ns_scale) >> TCLK2NS_SCALE_FACTOR; return cyc_to_sched_clock(&cd, cyc, (u32)~0);
} }
static struct timer_list cnt32_to_63_keepwarm_timer;
static void cnt32_to_63_keepwarm(unsigned long data) static void notrace orion_update_sched_clock(void)
{ {
mod_timer(&cnt32_to_63_keepwarm_timer, round_jiffies(jiffies + data)); u32 cyc = 0xffffffff - readl(TIMER0_VAL);
(void) sched_clock(); update_sched_clock(&cd, cyc, (u32)~0);
} }
static void __init setup_sched_clock(unsigned long tclk) static void __init setup_sched_clock(unsigned long tclk)
{ {
unsigned long long v; init_sched_clock(&cd, orion_update_sched_clock, 32, tclk);
unsigned long data;
v = NSEC_PER_SEC;
v <<= TCLK2NS_SCALE_FACTOR;
v += tclk/2;
do_div(v, tclk);
/*
* We want an even value to automatically clear the top bit
* returned by cnt32_to_63() without an additional run time
* instruction. So if the LSB is 1 then round it up.
*/
if (v & 1)
v++;
tclk2ns_scale = v;
data = (0xffffffffUL / tclk / 2 - 2) * HZ;
setup_timer(&cnt32_to_63_keepwarm_timer, cnt32_to_63_keepwarm, data);
mod_timer(&cnt32_to_63_keepwarm_timer, round_jiffies(jiffies + data));
} }
/* /*