sh: rework clocksource and sched_clock

Rework and simplify the sched_clock and clocksource code. Instead
of registering the clocksource in a shared file we move it into the
tmu driver. Also, add code to handle sched_clock in the case of no
clocksource.

Signed-off-by: Magnus Damm <damm@igel.co.jp>
Signed-off-by: Paul Mundt <lethal@linux-sh.org>

3 files changed, 19 insertions, 54 deletions

diff --git a/arch/sh/include/asm/timer.h b/arch/sh/include/asm/timer.h
index a7ca3a195bb5..4c3b66e30af2 100644
--- a/arch/sh/include/asm/timer.h
+++ b/arch/sh/include/asm/timer.h
@@ -9,7 +9,6 @@ struct sys_timer_ops {
         int (*init)(void);
         int (*start)(void);
         int (*stop)(void);
-        cycle_t (*read)(void);
 #ifndef CONFIG_GENERIC_TIME
         unsigned long (*get_offset)(void);
 #endif
@@ -39,6 +38,7 @@ struct sys_timer *get_sys_timer(void);
 
 /* arch/sh/kernel/time.c */
 void handle_timer_tick(void);
-extern unsigned long sh_hpt_frequency;
+
+extern struct clocksource clocksource_sh;
 
 #endif /* __ASM_SH_TIMER_H */
diff --git a/arch/sh/kernel/time_32.c b/arch/sh/kernel/time_32.c
index 8457f83242c5..ca22eef669ae 100644
--- a/arch/sh/kernel/time_32.c
+++ b/arch/sh/kernel/time_32.c
@@ -41,14 +41,6 @@ static int null_rtc_set_time(const time_t secs)
         return 0;
 }
 
-/*
- * Null high precision timer functions for systems lacking one.
- */
-static cycle_t null_hpt_read(void)
-{
-        return 0;
-}
-
 void (*rtc_sh_get_time)(struct timespec *) = null_rtc_get_time;
 int (*rtc_sh_set_time)(const time_t) = null_rtc_set_time;
 
@@ -200,42 +192,21 @@ device_initcall(timer_init_sysfs);
 
 void (*board_time_init)(void);
 
-/*
- * Shamelessly based on the MIPS and Sparc64 work.
- */
-static unsigned long timer_ticks_per_nsec_quotient __read_mostly;
-unsigned long sh_hpt_frequency = 0;
-
-#define NSEC_PER_CYC_SHIFT      10
-
-static struct clocksource clocksource_sh = {
+struct clocksource clocksource_sh = {
         .name           = "SuperH",
-        .rating         = 200,
-        .mask           = CLOCKSOURCE_MASK(32),
-        .read           = null_hpt_read,
-        .shift          = 16,
-        .flags          = CLOCK_SOURCE_IS_CONTINUOUS,
 };
 
-static void __init init_sh_clocksource(void)
-{
-        if (!sh_hpt_frequency || clocksource_sh.read == null_hpt_read)
-                return;
-
-        clocksource_sh.mult = clocksource_hz2mult(sh_hpt_frequency,
-                                                  clocksource_sh.shift);
-
-        timer_ticks_per_nsec_quotient =
-                clocksource_hz2mult(sh_hpt_frequency, NSEC_PER_CYC_SHIFT);
-
-        clocksource_register(&clocksource_sh);
-}
-
 #ifdef CONFIG_GENERIC_TIME
 unsigned long long sched_clock(void)
 {
-        unsigned long long ticks = clocksource_sh.read();
-        return (ticks * timer_ticks_per_nsec_quotient) >> NSEC_PER_CYC_SHIFT;
+        unsigned long long cycles;
+
+        /* jiffies based sched_clock if no clocksource is installed */
+        if (!clocksource_sh.rating)
+                return (unsigned long long)jiffies * (NSEC_PER_SEC / HZ);
+
+        cycles = clocksource_sh.read();
+        return cyc2ns(&clocksource_sh, cycles);
 }
 #endif
 
@@ -260,16 +231,4 @@ void __init time_init(void)
          */
         sys_timer = get_sys_timer();
         printk(KERN_INFO "Using %s for system timer\n", sys_timer->name);
-
-
-        if (sys_timer->ops->read)
-                clocksource_sh.read = sys_timer->ops->read;
-
-        init_sh_clocksource();
-
-        if (sh_hpt_frequency)
-                printk("Using %lu.%03lu MHz high precision timer.\n",
-                       ((sh_hpt_frequency + 500) / 1000) / 1000,
-                       ((sh_hpt_frequency + 500) / 1000) % 1000);
-
 }
diff --git a/arch/sh/kernel/timers/timer-tmu.c b/arch/sh/kernel/timers/timer-tmu.c
index 0db3f9510336..33a24fcf0a1d 100644
--- a/arch/sh/kernel/timers/timer-tmu.c
+++ b/arch/sh/kernel/timers/timer-tmu.c
@@ -254,7 +254,14 @@ static int tmu_timer_init(void)
 
         _tmu_start(TMU1);
 
-        sh_hpt_frequency = clk_get_rate(&tmu1_clk);
+        clocksource_sh.rating = 200;
+        clocksource_sh.mask = CLOCKSOURCE_MASK(32);
+        clocksource_sh.read = tmu_timer_read;
+        clocksource_sh.shift = 10;
+        clocksource_sh.mult = clocksource_hz2mult(clk_get_rate(&tmu1_clk),
+                                                  clocksource_sh.shift);
+        clocksource_sh.flags = CLOCK_SOURCE_IS_CONTINUOUS;
+        clocksource_register(&clocksource_sh);
 
         tmu0_clockevent.mult = div_sc(frequency, NSEC_PER_SEC,
                                       tmu0_clockevent.shift);
@@ -274,7 +281,6 @@ static struct sys_timer_ops tmu_timer_ops = {
         .init           = tmu_timer_init,
         .start          = tmu_timer_start,
         .stop           = tmu_timer_stop,
-        .read           = tmu_timer_read,
 };
 
 struct sys_timer tmu_timer = {