aboutsummaryrefslogtreecommitdiffstats
path: root/arch
diff options
context:
space:
mode:
authorJohn Stultz <johnstul@us.ibm.com>2010-03-19 12:23:57 -0400
committerMatt Turner <mattst88@monolith.freenet-rz.de>2010-05-26 00:40:27 +0200
commit9ce34c8f4466608bc67630a42d04f4aaf0443d9b (patch)
tree6a5822670410f567ebef147c8a69c0c0b66d5b05 /arch
parentec96e2fe954c23a54bfdf2673437a39e193a1822 (diff)
downloadmrst-s0i3-test-9ce34c8f4466608bc67630a42d04f4aaf0443d9b.tar.gz
mrst-s0i3-test-9ce34c8f4466608bc67630a42d04f4aaf0443d9b.tar.xz
mrst-s0i3-test-9ce34c8f4466608bc67630a42d04f4aaf0443d9b.zip
Convert alpha to use clocksources instead of arch_gettimeoffset
Alpha has a tsc like rpcc counter that it uses to manage time. This can be converted to an actual clocksource instead of utilizing the arch_gettimeoffset method that is really only there for legacy systems with no continuous counter. Further cleanups could be made if alpha converted to the clockevent model. CC: Thomas Gleixner <tglx@linutronix.de> CC: Richard Henderson <rth@twiddle.net> Acked-by: Ivan Kokshaysky <ink@jurassic.park.msu.ru> Tested-by: Ivan Kokshaysky <ink@jurassic.park.msu.ru> Signed-off-by: Matt Turner <mattst88@gmail.com> Signed-off-by: John Stultz <johnstul@us.ibm.com>
Diffstat (limited to 'arch')
-rw-r--r--arch/alpha/Kconfig4
-rw-r--r--arch/alpha/kernel/time.c69
2 files changed, 31 insertions, 42 deletions
diff --git a/arch/alpha/Kconfig b/arch/alpha/Kconfig
index b7193986cbf..24efdfe277f 100644
--- a/arch/alpha/Kconfig
+++ b/arch/alpha/Kconfig
@@ -51,10 +51,6 @@ config GENERIC_TIME
bool
default y
-config ARCH_USES_GETTIMEOFFSET
- bool
- default y
-
config GENERIC_CMOS_UPDATE
def_bool y
diff --git a/arch/alpha/kernel/time.c b/arch/alpha/kernel/time.c
index 5465e932e56..1efbed82c0f 100644
--- a/arch/alpha/kernel/time.c
+++ b/arch/alpha/kernel/time.c
@@ -51,6 +51,7 @@
#include <linux/mc146818rtc.h>
#include <linux/time.h>
#include <linux/timex.h>
+#include <linux/clocksource.h>
#include "proto.h"
#include "irq_impl.h"
@@ -332,6 +333,34 @@ rpcc_after_update_in_progress(void)
return rpcc();
}
+#ifndef CONFIG_SMP
+/* Until and unless we figure out how to get cpu cycle counters
+ in sync and keep them there, we can't use the rpcc. */
+static cycle_t read_rpcc(struct clocksource *cs)
+{
+ cycle_t ret = (cycle_t)rpcc();
+ return ret;
+}
+
+static struct clocksource clocksource_rpcc = {
+ .name = "rpcc",
+ .rating = 300,
+ .read = read_rpcc,
+ .mask = CLOCKSOURCE_MASK(32),
+ .flags = CLOCK_SOURCE_IS_CONTINUOUS
+};
+
+static inline void register_rpcc_clocksource(long cycle_freq)
+{
+ clocksource_calc_mult_shift(&clocksource_rpcc, cycle_freq, 4);
+ clocksource_register(&clocksource_rpcc);
+}
+#else /* !CONFIG_SMP */
+static inline void register_rpcc_clocksource(long cycle_freq)
+{
+}
+#endif /* !CONFIG_SMP */
+
void __init
time_init(void)
{
@@ -385,6 +414,8 @@ time_init(void)
__you_loose();
}
+ register_rpcc_clocksource(cycle_freq);
+
state.last_time = cc1;
state.scaled_ticks_per_cycle
= ((unsigned long) HZ << FIX_SHIFT) / cycle_freq;
@@ -395,44 +426,6 @@ time_init(void)
}
/*
- * Use the cycle counter to estimate an displacement from the last time
- * tick. Unfortunately the Alpha designers made only the low 32-bits of
- * the cycle counter active, so we overflow on 8.2 seconds on a 500MHz
- * part. So we can't do the "find absolute time in terms of cycles" thing
- * that the other ports do.
- */
-u32 arch_gettimeoffset(void)
-{
-#ifdef CONFIG_SMP
- /* Until and unless we figure out how to get cpu cycle counters
- in sync and keep them there, we can't use the rpcc tricks. */
- return 0;
-#else
- unsigned long delta_cycles, delta_usec, partial_tick;
-
- delta_cycles = rpcc() - state.last_time;
- partial_tick = state.partial_tick;
- /*
- * usec = cycles * ticks_per_cycle * 2**48 * 1e6 / (2**48 * ticks)
- * = cycles * (s_t_p_c) * 1e6 / (2**48 * ticks)
- * = cycles * (s_t_p_c) * 15625 / (2**42 * ticks)
- *
- * which, given a 600MHz cycle and a 1024Hz tick, has a
- * dynamic range of about 1.7e17, which is less than the
- * 1.8e19 in an unsigned long, so we are safe from overflow.
- *
- * Round, but with .5 up always, since .5 to even is harder
- * with no clear gain.
- */
-
- delta_usec = (delta_cycles * state.scaled_ticks_per_cycle
- + partial_tick) * 15625;
- delta_usec = ((delta_usec / ((1UL << (FIX_SHIFT-6-1)) * HZ)) + 1) / 2;
- return delta_usec * 1000;
-#endif
-}
-
-/*
* In order to set the CMOS clock precisely, set_rtc_mmss has to be
* called 500 ms after the second nowtime has started, because when
* nowtime is written into the registers of the CMOS clock, it will