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ARM: sa1100: convert sched_clock() to use new infrastructure

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Convert sa1100 to use the new sched_clock() infrastructure for extending
32bit counters to full 64-bit nanoseconds.

Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
This commit is contained in:
Russell King 2010-12-15 21:49:06 +00:00
parent 7ce8301881
commit 5094b92f1c
3 changed files with 31 additions and 23 deletions
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1
arch/arm/Kconfig
View File

@ -642,6 +642,7 @@ config ARCH_SA1100
select CPU_FREQ
select GENERIC_CLOCKEVENTS
select HAVE_CLK
select HAVE_SCHED_CLOCK
select TICK_ONESHOT
select ARCH_REQUIRE_GPIOLIB
help

23
arch/arm/mach-sa1100/generic.c
View File

@ -16,9 +16,7 @@
#include <linux/pm.h>
#include <linux/cpufreq.h>
#include <linux/ioport.h>
#include <linux/sched.h> /* just for sched_clock() - funny that */
#include <linux/platform_device.h>
#include <linux/cnt32_to_63.h>
#include <asm/div64.h>
#include <mach/hardware.h>
@ -109,27 +107,6 @@ unsigned int sa11x0_getspeed(unsigned int cpu)
return cclk_frequency_100khz[PPCR & 0xf] * 100;
}
/*
* This is the SA11x0 sched_clock implementation. This has
* a resolution of 271ns, and a maximum value of 32025597s (370 days).
*
* The return value is guaranteed to be monotonic in that range as
* long as there is always less than 582 seconds between successive
* calls to this function.
*
* ( * 1E9 / 3686400 => * 78125 / 288)
*/
unsigned long long notrace sched_clock(void)
{
unsigned long long v = cnt32_to_63(OSCR);
/* the <<1 gets rid of the cnt_32_to_63 top bit saving on a bic insn */
v *= 78125<<1;
do_div(v, 288<<1);
return v;
}
/*
* Default power-off for SA1100
*/

30
arch/arm/mach-sa1100/time.c
View File

@ -12,12 +12,39 @@
#include <linux/errno.h>
#include <linux/interrupt.h>
#include <linux/irq.h>
#include <linux/sched.h> /* just for sched_clock() - funny that */
#include <linux/timex.h>
#include <linux/clockchips.h>
#include <asm/mach/time.h>
#include <asm/sched_clock.h>
#include <mach/hardware.h>
/*
* This is the SA11x0 sched_clock implementation.
*/
static DEFINE_CLOCK_DATA(cd);
/*
* Constants generated by clocks_calc_mult_shift(m, s, 3.6864MHz,
* NSEC_PER_SEC, 60).
* This gives a resolution of about 271ns and a wrap period of about 19min.
*/
#define SC_MULT 2275555556u
#define SC_SHIFT 23
unsigned long long notrace sched_clock(void)
{
u32 cyc = OSCR;
return cyc_to_fixed_sched_clock(&cd, cyc, (u32)~0, SC_MULT, SC_SHIFT);
}
static void notrace sa1100_update_sched_clock(void)
{
u32 cyc = OSCR;
update_sched_clock(&cd, cyc, (u32)~0);
}
#define MIN_OSCR_DELTA 2
static irqreturn_t sa1100_ost0_interrupt(int irq, void *dev_id)
@ -96,6 +123,9 @@ static void __init sa1100_timer_init(void)
OIER = 0; /* disable any timer interrupts */
OSSR = 0xf; /* clear status on all timers */
init_fixed_sched_clock(&cd, sa1100_update_sched_clock, 32,
3686400, SC_MULT, SC_SHIFT);
ckevt_sa1100_osmr0.mult =
div_sc(3686400, NSEC_PER_SEC, ckevt_sa1100_osmr0.shift);
ckevt_sa1100_osmr0.max_delta_ns =