Re: [PATCH] FRV: do_gettimeofday() should no longer use tickadj

john stultz
2006-09-06T01:47:10Z

On Tue, 2006-09-05 at 16:35 +0100, David Howells wrote:
> Stop do_gettimeofday() on FRV from using tickadj, and model it after ARM
> instead.
>
> This patch also provides a placeholder macro for getting hardware timer data to
> be filled in when such is available.

>From this patch it looks like the FRV arch could be trivially converted
to GENERIC_TIME.

Would you consider the following, totally untested patch?

Signed-off-by: John Stultz <johnstul@us.ibm.com>

Kconfig | 4 ++
kernel/time.c | 81 ----------------------------------------------------------
2 files changed, 4 insertions(+), 81 deletions(-)

diff --git a/arch/frv/Kconfig b/arch/frv/Kconfig
index 95a3892..a601a17 100644
--- a/arch/frv/Kconfig
+++ b/arch/frv/Kconfig
@@ -29,6 +29,10 @@ config GENERIC_HARDIRQS
bool
default n

+config GENERIC_TIME
+ bool
+ default y
+
config TIME_LOW_RES
bool
default y
diff --git a/arch/frv/kernel/time.c b/arch/frv/kernel/time.c
index d5b64e1..68a77fe 100644
--- a/arch/frv/kernel/time.c
+++ b/arch/frv/kernel/time.c
@@ -32,8 +32,6 @@

#define TICK_SIZE (tick_nsec / 1000)

-extern unsigned long wall_jiffies;
-
unsigned long __nongprelbss __clkin_clock_speed_HZ;
unsigned long __nongprelbss __ext_bus_clock_speed_HZ;
unsigned long __nongprelbss __res_bus_clock_speed_HZ;
@@ -145,85 +143,6 @@ void time_init(void)
}

/*
- * This version of gettimeofday has near microsecond resolution.
- */
-void do_gettimeofday(struct timeval *tv)
-{
- unsigned long seq;
- unsigned long usec, sec;
- unsigned long max_ntp_tick;
-
- do {
- unsigned long lost;
-
- seq = read_seqbegin(&xtime_lock);
-
- usec = 0;
- lost = jiffies - wall_jiffies;
-
- /*
- * If time_adjust is negative then NTP is slowing the clock
- * so make sure not to go into next possible interval.
- * Better to lose some accuracy than have time go backwards..
- */
- if (unlikely(time_adjust < 0)) {
- max_ntp_tick = (USEC_PER_SEC / HZ) - tickadj;
- usec = min(usec, max_ntp_tick);
-
- if (lost)
- usec += lost * max_ntp_tick;
- }
- else if (unlikely(lost))
- usec += lost * (USEC_PER_SEC / HZ);
-
- sec = xtime.tv_sec;
- usec += (xtime.tv_nsec / 1000);
- } while (read_seqretry(&xtime_lock, seq));
-
- while (usec >= 1000000) {
- usec -= 1000000;
- sec++;
- }
-
- tv->tv_sec = sec;
- tv->tv_usec = usec;
-}
-
-EXPORT_SYMBOL(do_gettimeofday);
-
-int do_settimeofday(struct timespec *tv)
-{
- time_t wtm_sec, sec = tv->tv_sec;
- long wtm_nsec, nsec = tv->tv_nsec;
-
- if ((unsigned long)tv->tv_nsec >= NSEC_PER_SEC)
- return -EINVAL;
-
- write_seqlock_irq(&xtime_lock);
- /*
- * This is revolting. We need to set "xtime" correctly. However, the
- * value in this location is the value at the most recent update of
- * wall time. Discover what correction gettimeofday() would have
- * made, and then undo it!
- */
- nsec -= 0 * NSEC_PER_USEC;
- nsec -= (jiffies - wall_jiffies) * TICK_NSEC;
-
- wtm_sec = wall_to_monotonic.tv_sec + (xtime.tv_sec - sec);
- wtm_nsec = wall_to_monotonic.tv_nsec + (xtime.tv_nsec - nsec);
-
- set_normalized_timespec(&xtime, sec, nsec);
- set_normalized_timespec(&wall_to_monotonic, wtm_sec, wtm_nsec);
-
- ntp_clear();
- write_sequnlock_irq(&xtime_lock);
- clock_was_set();
- return 0;
-}
-
-EXPORT_SYMBOL(do_settimeofday);
-
-/*
* Scheduler clock - returns current time in nanosec units.
*/
unsigned long long sched_clock(void)