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authorRussell King <rmk+kernel@arm.linux.org.uk>2010-12-15 21:49:06 +0000
committerRussell King <rmk+kernel@arm.linux.org.uk>2010-12-22 22:44:46 +0000
commit5094b92f1c7d0f21c5d4411ba7415bac0684210f (patch)
treedd7ea2777e5c0470fe7c46c9b8ec3ed16885ddcb /arch/arm/mach-sa1100
parent7ce830188199c23aaeaf0c5ccc28b73c32b6df02 (diff)
downloadop-kernel-dev-5094b92f1c7d0f21c5d4411ba7415bac0684210f.zip
op-kernel-dev-5094b92f1c7d0f21c5d4411ba7415bac0684210f.tar.gz
ARM: sa1100: convert sched_clock() to use new infrastructure
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>
Diffstat (limited to 'arch/arm/mach-sa1100')
-rw-r--r--arch/arm/mach-sa1100/generic.c23
-rw-r--r--arch/arm/mach-sa1100/time.c30
2 files changed, 30 insertions, 23 deletions
diff --git a/arch/arm/mach-sa1100/generic.c b/arch/arm/mach-sa1100/generic.c
index 33b4969..fbc224d 100644
--- a/arch/arm/mach-sa1100/generic.c
+++ b/arch/arm/mach-sa1100/generic.c
@@ -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>
@@ -110,27 +108,6 @@ unsigned int sa11x0_getspeed(unsigned int cpu)
}
/*
- * 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
*/
static void sa1100_power_off(void)
diff --git a/arch/arm/mach-sa1100/time.c b/arch/arm/mach-sa1100/time.c
index 96154f5..ae4f3d8 100644
--- a/arch/arm/mach-sa1100/time.c
+++ b/arch/arm/mach-sa1100/time.c
@@ -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 =
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