[PATCH 2/3] Convert sh to use arch_getoffset() infrastructure

[john stultz <johnstul@us.ibm.com>]

Andrew, please consider for inclusion into -mm in preparation for 2.6.30

This patch converts sh to use GENERIC_TIME via the arch_getoffset()
infrastructure 

I do not have cross compilers for these architectures, and in some cases
the architectures can be compiles both with and without clocksources. So
I've taken my best swing at converting this, but I'm not confident I got
it right. Any assistance from arch maintainers or testers would be
great.

Signed-off-by: John Stultz <johnstul@us.ibm.com>
Acked-by: Paul Mundt <lethal@linux-sh.org>

diff --git a/arch/sh/Kconfig b/arch/sh/Kconfig
index ebabe51..c48ab20 100644
--- a/arch/sh/Kconfig
+++ b/arch/sh/Kconfig
@@ -72,7 +72,7 @@ config GENERIC_IOMAP
 	bool
 
 config GENERIC_TIME
-	def_bool n
+	def_bool y
 
 config GENERIC_CLOCKEVENTS
 	def_bool n
@@ -406,6 +406,10 @@ config SH_TMU
 	help
 	  This enables the use of the TMU as the system timer.
 
+config ARCH_USES_GETTIMEOFFSET
+	def_bool y
+	depends on !SH_TMU
+
 config SH_CMT
 	def_bool y
 	prompt "CMT timer support"
diff --git a/arch/sh/include/asm/timer.h b/arch/sh/include/asm/timer.h
index a7ca3a1..da122a3 100644
--- a/arch/sh/include/asm/timer.h
+++ b/arch/sh/include/asm/timer.h
@@ -10,7 +10,7 @@ struct sys_timer_ops {
 	int (*start)(void);
 	int (*stop)(void);
 	cycle_t (*read)(void);
-#ifndef CONFIG_GENERIC_TIME
+#ifdef CONFIG_ARCH_USES_GETTIMEOFFSET
 	unsigned long (*get_offset)(void);
 #endif
 };
@@ -27,7 +27,7 @@ struct sys_timer {
 extern struct sys_timer tmu_timer, cmt_timer, mtu2_timer;
 extern struct sys_timer *sys_timer;
 
-#ifndef CONFIG_GENERIC_TIME
+#ifdef CONFIG_ARCH_USES_GETTIMEOFFSET
 static inline unsigned long get_timer_offset(void)
 {
 	return sys_timer->ops->get_offset();
diff --git a/arch/sh/kernel/time_32.c b/arch/sh/kernel/time_32.c
index 8457f83..8e9827a 100644
--- a/arch/sh/kernel/time_32.c
+++ b/arch/sh/kernel/time_32.c
@@ -52,65 +52,12 @@ static cycle_t null_hpt_read(void)
 void (*rtc_sh_get_time)(struct timespec *) = null_rtc_get_time;
 int (*rtc_sh_set_time)(const time_t) = null_rtc_set_time;
 
-#ifndef CONFIG_GENERIC_TIME
-void do_gettimeofday(struct timeval *tv)
+#ifdef CONFIG_ARCH_USES_GETTIMEOFFSET
+u32 arch_gettimeoffset(void)
 {
-	unsigned long flags;
-	unsigned long seq;
-	unsigned long usec, sec;
-
-	do {
-		/*
-		 * Turn off IRQs when grabbing xtime_lock, so that
-		 * the sys_timer get_offset code doesn't have to handle it.
-		 */
-		seq = read_seqbegin_irqsave(&xtime_lock, flags);
-		usec = get_timer_offset();
-		sec = xtime.tv_sec;
-		usec += xtime.tv_nsec / NSEC_PER_USEC;
-	} while (read_seqretry_irqrestore(&xtime_lock, seq, flags));
-
-	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 -= get_timer_offset() * NSEC_PER_USEC;
-
-	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;
+	return get_timer_offset() * 1000;
 }
-EXPORT_SYMBOL(do_settimeofday);
-#endif /* !CONFIG_GENERIC_TIME */
+#endif /* CONFIG_ARCH_USES_GETTIMEOFFSET */
 
 #ifndef CONFIG_GENERIC_CLOCKEVENTS
 /* last time the RTC clock got updated */
@@ -231,7 +178,7 @@ static void __init init_sh_clocksource(void)
 	clocksource_register(&clocksource_sh);
 }
 
-#ifdef CONFIG_GENERIC_TIME
+#ifndef CONFIG_ARCH_USES_GETTIMEOFFSET
 unsigned long long sched_clock(void)
 {
 	unsigned long long ticks = clocksource_sh.read();
diff --git a/arch/sh/kernel/time_64.c b/arch/sh/kernel/time_64.c
index 59d2a03..cfd75d8 100644
--- a/arch/sh/kernel/time_64.c
+++ b/arch/sh/kernel/time_64.c
@@ -144,59 +144,10 @@ static unsigned long usecs_since_tick(void)
 	return result;
 }
 
-void do_gettimeofday(struct timeval *tv)
+u32 arch_gettimeoffset(void)
 {
-	unsigned long flags;
-	unsigned long seq;
-	unsigned long usec, sec;
-
-	do {
-		seq = read_seqbegin_irqsave(&xtime_lock, flags);
-		usec = usecs_since_tick();
-		sec = xtime.tv_sec;
-		usec += xtime.tv_nsec / 1000;
-	} while (read_seqretry_irqrestore(&xtime_lock, seq, flags));
-
-	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 -= 1000 * usecs_since_tick();
-
-	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;
+	return usecs_since_tick() * 1000;
 }
-EXPORT_SYMBOL(do_settimeofday);
 
 /* Dummy RTC ops */
 static void null_rtc_get_time(struct timespec *tv)
diff --git a/arch/sh/kernel/timers/timer-cmt.c b/arch/sh/kernel/timers/timer-cmt.c
index c127293..6c729db 100644
--- a/arch/sh/kernel/timers/timer-cmt.c
+++ b/arch/sh/kernel/timers/timer-cmt.c
@@ -178,7 +178,7 @@ static struct sys_timer_ops cmt_timer_ops = {
 	.init		= cmt_timer_init,
 	.start		= cmt_timer_start,
 	.stop		= cmt_timer_stop,
-#ifndef CONFIG_GENERIC_TIME
+#ifdef CONFIG_ARCH_USES_GETTIMEOFFSET
 	.get_offset	= cmt_timer_get_offset,
 #endif
 };
diff --git a/arch/sh/kernel/timers/timer-mtu2.c b/arch/sh/kernel/timers/timer-mtu2.c
index c3d237e..acf6a96 100644
--- a/arch/sh/kernel/timers/timer-mtu2.c
+++ b/arch/sh/kernel/timers/timer-mtu2.c
@@ -191,7 +191,7 @@ struct sys_timer_ops mtu2_timer_ops = {
 	.init		= mtu2_timer_init,
 	.start		= mtu2_timer_start,
 	.stop		= mtu2_timer_stop,
-#ifndef CONFIG_GENERIC_TIME
+#ifdef CONFIG_ARCH_USES_GETTIMEOFFSET
 	.get_offset	= mtu2_timer_get_offset,
 #endif
 };