sh: clockevent/clocksource/hrtimers/nohz TMU support.
This adds basic support for clockevents and clocksources,
presently only implemented for TMU-based systems (which
are the majority of SH-3 and SH-4 systems).
The old NO_IDLE_HZ implementation is also dropped completely,
the only users of this were on TMU-based systems anyways.
More work needs to be done to generalize the TMU handling,
in that the current implementation is rather tied to the
notion of TMU0 and TMU1 utilization.
Additionally, as more SH timers switch over to this scheme,
we'll be able to gut most of the remaining system timer
infrastructure that existed before.
Signed-off-by: Paul Mundt <lethal@linux-sh.org>
diff --git a/arch/sh/kernel/time.c b/arch/sh/kernel/time.c
index d47e775..a3a67d1 100644
--- a/arch/sh/kernel/time.c
+++ b/arch/sh/kernel/time.c
@@ -3,7 +3,7 @@
*
* Copyright (C) 1999 Tetsuya Okada & Niibe Yutaka
* Copyright (C) 2000 Philipp Rumpf <prumpf@tux.org>
- * Copyright (C) 2002 - 2006 Paul Mundt
+ * Copyright (C) 2002 - 2007 Paul Mundt
* Copyright (C) 2002 M. R. Brown <mrbrown@linux-sh.org>
*
* Some code taken from i386 version.
@@ -15,6 +15,7 @@
#include <linux/profile.h>
#include <linux/timex.h>
#include <linux/sched.h>
+#include <linux/clockchips.h>
#include <asm/clock.h>
#include <asm/rtc.h>
#include <asm/timer.h>
@@ -38,6 +39,14 @@
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;
@@ -101,6 +110,7 @@
EXPORT_SYMBOL(do_settimeofday);
#endif /* !CONFIG_GENERIC_TIME */
+#ifndef CONFIG_GENERIC_CLOCKEVENTS
/* last time the RTC clock got updated */
static long last_rtc_update;
@@ -138,6 +148,7 @@
last_rtc_update = xtime.tv_sec - 600;
}
}
+#endif /* !CONFIG_GENERIC_CLOCKEVENTS */
#ifdef CONFIG_PM
int timer_suspend(struct sys_device *dev, pm_message_t state)
@@ -168,108 +179,6 @@
.resume = timer_resume,
};
-#ifdef CONFIG_NO_IDLE_HZ
-static int timer_dyn_tick_enable(void)
-{
- struct dyn_tick_timer *dyn_tick = sys_timer->dyn_tick;
- unsigned long flags;
- int ret = -ENODEV;
-
- if (dyn_tick) {
- spin_lock_irqsave(&dyn_tick->lock, flags);
- ret = 0;
- if (!(dyn_tick->state & DYN_TICK_ENABLED)) {
- ret = dyn_tick->enable();
-
- if (ret == 0)
- dyn_tick->state |= DYN_TICK_ENABLED;
- }
- spin_unlock_irqrestore(&dyn_tick->lock, flags);
- }
-
- return ret;
-}
-
-static int timer_dyn_tick_disable(void)
-{
- struct dyn_tick_timer *dyn_tick = sys_timer->dyn_tick;
- unsigned long flags;
- int ret = -ENODEV;
-
- if (dyn_tick) {
- spin_lock_irqsave(&dyn_tick->lock, flags);
- ret = 0;
- if (dyn_tick->state & DYN_TICK_ENABLED) {
- ret = dyn_tick->disable();
-
- if (ret == 0)
- dyn_tick->state &= ~DYN_TICK_ENABLED;
- }
- spin_unlock_irqrestore(&dyn_tick->lock, flags);
- }
-
- return ret;
-}
-
-/*
- * Reprogram the system timer for at least the calculated time interval.
- * This function should be called from the idle thread with IRQs disabled,
- * immediately before sleeping.
- */
-void timer_dyn_reprogram(void)
-{
- struct dyn_tick_timer *dyn_tick = sys_timer->dyn_tick;
- unsigned long next, seq, flags;
-
- if (!dyn_tick)
- return;
-
- spin_lock_irqsave(&dyn_tick->lock, flags);
- if (dyn_tick->state & DYN_TICK_ENABLED) {
- next = next_timer_interrupt();
- do {
- seq = read_seqbegin(&xtime_lock);
- dyn_tick->reprogram(next - jiffies);
- } while (read_seqretry(&xtime_lock, seq));
- }
- spin_unlock_irqrestore(&dyn_tick->lock, flags);
-}
-
-static ssize_t timer_show_dyn_tick(struct sys_device *dev, char *buf)
-{
- return sprintf(buf, "%i\n",
- (sys_timer->dyn_tick->state & DYN_TICK_ENABLED) >> 1);
-}
-
-static ssize_t timer_set_dyn_tick(struct sys_device *dev, const char *buf,
- size_t count)
-{
- unsigned int enable = simple_strtoul(buf, NULL, 2);
-
- if (enable)
- timer_dyn_tick_enable();
- else
- timer_dyn_tick_disable();
-
- return count;
-}
-static SYSDEV_ATTR(dyn_tick, 0644, timer_show_dyn_tick, timer_set_dyn_tick);
-
-/*
- * dyntick=enable|disable
- */
-static char dyntick_str[4] __initdata = "";
-
-static int __init dyntick_setup(char *str)
-{
- if (str)
- strlcpy(dyntick_str, str, sizeof(dyntick_str));
- return 1;
-}
-
-__setup("dyntick=", dyntick_setup);
-#endif
-
static int __init timer_init_sysfs(void)
{
int ret = sysdev_class_register(&timer_sysclass);
@@ -277,27 +186,51 @@
return ret;
sys_timer->dev.cls = &timer_sysclass;
- ret = sysdev_register(&sys_timer->dev);
-
-#ifdef CONFIG_NO_IDLE_HZ
- if (ret == 0 && sys_timer->dyn_tick) {
- ret = sysdev_create_file(&sys_timer->dev, &attr_dyn_tick);
-
- /*
- * Turn on dynamic tick after calibrate delay
- * for correct bogomips
- */
- if (ret == 0 && dyntick_str[0] == 'e')
- ret = timer_dyn_tick_enable();
- }
-#endif
-
- return ret;
+ return sysdev_register(&sys_timer->dev);
}
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
+
+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;
+}
+#endif
+
void __init time_init(void)
{
if (board_time_init)
@@ -316,10 +249,15 @@
sys_timer = get_sys_timer();
printk(KERN_INFO "Using %s for system timer\n", sys_timer->name);
-#ifdef CONFIG_NO_IDLE_HZ
- if (sys_timer->dyn_tick)
- spin_lock_init(&sys_timer->dyn_tick->lock);
-#endif
+ 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);
#if defined(CONFIG_SH_KGDB)
/*