Andrew, All,
Here is an updated version of the smaller, reworked and
improved patchset I mailed out monday. Please consider for inclusion
into your tree.
Again, the majority of this new incremental design should be credited
to Roman Zippel, but it is my implementation, so he gets the credit and
I get the blame. :)
Summary:
This patchset provides a generic timekeeping infrastructure
that are independent of the timer interrupt. This allows for robust and
correct behavior in cases of late or lost ticks, avoids interpolation
errors, reduces duplication in arch specific code, and allows or
assists future changes such as high-res timers, dynamic ticks, or
realtime preemption. Additionally, it provides finer nanosecond
resolution values to the clock_gettime functions. The patchset also
converts the i386 arch to use this new infrastructure.
Changes since the C0 release:
o Cut out functions that are no longer used
o Re-arranged patch chunks so each patch makes more sense.
o Few small fixes.
o Improved comments.
On my TODO list:
o More attention on x86-64 and powerpc
o Re-add bits needed for inclusion into HRT and RT
o Try to restore cleanups via small patches
The patchset applies against the current 2.6.16-git.
The complete patchset can be found here:
http://sr71.net/~jstultz/tod/
I'd like to thank the following people who have contributed ideas,
criticism, testing and code that has helped shape this work:
George Anzinger, Nish Aravamudan, Max Asbock, Serge Belyshev,
Dominik Brodowski, Adrian Bunk, Thomas Gleixner, Darren Hart, Christoph
Lameter, Matt Mackal, Keith Mannthey, Ingo Molnar, Andrew Morton, Paul
Munt, Martin Schwidefsky, Frank Sorenson, Ulrich Windl, Jonathan
Woithe, Darrick Wong, Roman Zippel and any others whom I've
accidentally left off this list.
thanks
-john
This patch is just a simple cleanup for the i386 arch in
preparation of moving to the generic timeofday infrastructure. It
simply moves the PIT initialization code, locks, and other code we want
to keep from some code from timer_pit.c (which will be removed) to
i8253.c.
thanks
-john
Signed-off-by: John Stultz <[email protected]>
Makefile | 2 +-
i8253.c | 32 ++++++++++++++++++++++++++++++++
time.c | 5 -----
timers/timer_pit.c | 13 -------------
4 files changed, 33 insertions(+), 19 deletions(-)
linux-2.6.16_timeofday-arch-i386-part1_C1.patch
============================================
diff --git a/arch/i386/kernel/Makefile b/arch/i386/kernel/Makefile
index 65656c0..687a29b 100644
--- a/arch/i386/kernel/Makefile
+++ b/arch/i386/kernel/Makefile
@@ -7,7 +7,7 @@ extra-y := head.o init_task.o vmlinux.ld
obj-y := process.o semaphore.o signal.o entry.o traps.o irq.o \
ptrace.o time.o ioport.o ldt.o setup.o i8259.o sys_i386.o \
pci-dma.o i386_ksyms.o i387.o dmi_scan.o bootflag.o \
- quirks.o i8237.o topology.o
+ quirks.o i8237.o i8253.o topology.o
obj-y += cpu/
obj-y += timers/
diff --git a/arch/i386/kernel/i8253.c b/arch/i386/kernel/i8253.c
new file mode 100644
index 0000000..29cb2eb
--- /dev/null
+++ b/arch/i386/kernel/i8253.c
@@ -0,0 +1,32 @@
+/*
+ * i8253.c 8253/PIT functions
+ *
+ */
+#include <linux/spinlock.h>
+#include <linux/jiffies.h>
+#include <linux/sysdev.h>
+#include <linux/module.h>
+#include <linux/init.h>
+
+#include <asm/smp.h>
+#include <asm/delay.h>
+#include <asm/i8253.h>
+#include <asm/io.h>
+
+#include "io_ports.h"
+
+DEFINE_SPINLOCK(i8253_lock);
+EXPORT_SYMBOL(i8253_lock);
+
+void setup_pit_timer(void)
+{
+ unsigned long flags;
+
+ spin_lock_irqsave(&i8253_lock, flags);
+ outb_p(0x34,PIT_MODE); /* binary, mode 2, LSB/MSB, ch 0 */
+ udelay(10);
+ outb_p(LATCH & 0xff , PIT_CH0); /* LSB */
+ udelay(10);
+ outb(LATCH >> 8 , PIT_CH0); /* MSB */
+ spin_unlock_irqrestore(&i8253_lock, flags);
+}
diff --git a/arch/i386/kernel/time.c b/arch/i386/kernel/time.c
index 9d30747..796e5fa 100644
--- a/arch/i386/kernel/time.c
+++ b/arch/i386/kernel/time.c
@@ -82,11 +82,6 @@ extern unsigned long wall_jiffies;
DEFINE_SPINLOCK(rtc_lock);
EXPORT_SYMBOL(rtc_lock);
-#include <asm/i8253.h>
-
-DEFINE_SPINLOCK(i8253_lock);
-EXPORT_SYMBOL(i8253_lock);
-
struct timer_opts *cur_timer __read_mostly = &timer_none;
/*
diff --git a/arch/i386/kernel/timers/timer_pit.c b/arch/i386/kernel/timers/timer_pit.c
index b9b6bd5..44cbdf9 100644
--- a/arch/i386/kernel/timers/timer_pit.c
+++ b/arch/i386/kernel/timers/timer_pit.c
@@ -162,16 +162,3 @@ struct init_timer_opts __initdata timer_
.init = init_pit,
.opts = &timer_pit,
};
-
-void setup_pit_timer(void)
-{
- unsigned long flags;
-
- spin_lock_irqsave(&i8253_lock, flags);
- outb_p(0x34,PIT_MODE); /* binary, mode 2, LSB/MSB, ch 0 */
- udelay(10);
- outb_p(LATCH & 0xff , PIT_CH0); /* LSB */
- udelay(10);
- outb(LATCH >> 8 , PIT_CH0); /* MSB */
- spin_unlock_irqrestore(&i8253_lock, flags);
-}
Introduces clocksource switching code and the arch generic time
accessor functions that use the clocksource infrastructure.
Signed-off-by: John Stultz <[email protected]>
include/linux/time.h | 15 ++++
kernel/time.c | 2
kernel/timer.c | 170 +++++++++++++++++++++++++++++++++++++++++++++++++++
3 files changed, 187 insertions(+)
linux-2.6.16_timeofday-core4_C1.patch
============================================
diff --git a/include/linux/time.h b/include/linux/time.h
index 84cfa7b..fc06884 100644
--- a/include/linux/time.h
+++ b/include/linux/time.h
@@ -107,6 +107,7 @@ extern int do_getitimer(int which, struc
extern void getnstimeofday(struct timespec *tv);
extern struct timespec timespec_trunc(struct timespec t, unsigned gran);
+extern int timekeeping_is_continuous(void);
/**
* timespec_to_ns - Convert timespec to nanoseconds
@@ -149,6 +150,20 @@ extern struct timespec ns_to_timespec(co
*/
extern struct timeval ns_to_timeval(const nsec_t nsec);
+/**
+ * timespec_add_ns - Adds nanoseconds to a timespec
+ * @a: pointer to timespec to be incremented
+ * @ns: unsigned nanoseconds value to be added
+ */
+static inline void timespec_add_ns(struct timespec *a, u64 ns)
+{
+ ns += a->tv_nsec;
+ while(unlikely(ns >= NSEC_PER_SEC)) {
+ ns -= NSEC_PER_SEC;
+ a->tv_sec++;
+ }
+ a->tv_nsec = ns;
+}
#endif /* __KERNEL__ */
#define NFDBITS __NFDBITS
diff --git a/kernel/time.c b/kernel/time.c
index 8045391..526fbdb 100644
--- a/kernel/time.c
+++ b/kernel/time.c
@@ -550,6 +550,7 @@ EXPORT_SYMBOL(do_gettimeofday);
#else
+#ifndef CONFIG_GENERIC_TIME
/*
* Simulate gettimeofday using do_gettimeofday which only allows a timeval
* and therefore only yields usec accuracy
@@ -564,6 +565,7 @@ void getnstimeofday(struct timespec *tv)
}
EXPORT_SYMBOL_GPL(getnstimeofday);
#endif
+#endif
/* Converts Gregorian date to seconds since 1970-01-01 00:00:00.
* Assumes input in normal date format, i.e. 1980-12-31 23:59:59
diff --git a/kernel/timer.c b/kernel/timer.c
index 339d52f..0c1e184 100644
--- a/kernel/timer.c
+++ b/kernel/timer.c
@@ -806,6 +806,169 @@ u64 current_tick_length(long shift)
#include <linux/clocksource.h>
static struct clocksource *clock; /* pointer to current clocksource */
static cycle_t last_clock_cycle; /* cycle value at last update_wall_time */
+
+#ifdef CONFIG_GENERIC_TIME
+/**
+ * __get_nsec_offset - Returns nanoseconds since last call to periodic_hook
+ *
+ * private function, must hold xtime_lock lock when being
+ * called. Returns the number of nanoseconds since the
+ * last call to update_wall_time() (adjusted by NTP scaling)
+ */
+static inline s64 __get_nsec_offset(void)
+{
+ cycle_t cycle_now, cycle_delta;
+ s64 ns_offset;
+
+ /* read clocksource: */
+ cycle_now = read_clocksource(clock);
+
+ /* calculate the delta since the last update_wall_time: */
+ cycle_delta = (cycle_now - last_clock_cycle) & clock->mask;
+
+ /* convert to nanoseconds: */
+ ns_offset = cyc2ns(clock, cycle_delta);
+
+ return ns_offset;
+}
+
+/**
+ * __get_realtime_clock_ts - Returns the time of day in a timespec
+ * @ts: pointer to the timespec to be set
+ *
+ * Returns the time of day in a timespec. Used by
+ * do_gettimeofday() and get_realtime_clock_ts().
+ */
+static inline void __get_realtime_clock_ts(struct timespec *ts)
+{
+ unsigned long seq;
+ s64 nsecs;
+
+ do {
+ seq = read_seqbegin(&xtime_lock);
+
+ *ts = xtime;
+ nsecs = __get_nsec_offset();
+
+ } while (read_seqretry(&xtime_lock, seq));
+
+ timespec_add_ns(ts, nsecs);
+}
+
+/**
+ * get_realtime_clock_ts - Returns the time of day in a timespec
+ * @ts: pointer to the timespec to be set
+ *
+ * Returns the time of day in a timespec.
+ */
+void getnstimeofday(struct timespec *ts)
+{
+ __get_realtime_clock_ts(ts);
+}
+
+EXPORT_SYMBOL(getnstimeofday);
+
+/**
+ * do_gettimeofday - Returns the time of day in a timeval
+ * @tv: pointer to the timeval to be set
+ *
+ * NOTE: Users should be converted to using get_realtime_clock_ts()
+ */
+void do_gettimeofday(struct timeval *tv)
+{
+ struct timespec now;
+
+ __get_realtime_clock_ts(&now);
+ tv->tv_sec = now.tv_sec;
+ tv->tv_usec = now.tv_nsec/1000;
+}
+
+EXPORT_SYMBOL(do_gettimeofday);
+/**
+ * do_settimeofday - Sets the time of day
+ * @tv: pointer to the timespec variable containing the new time
+ *
+ * Sets the time of day to the new time and update NTP and notify hrtimers
+ */
+int do_settimeofday(struct timespec *tv)
+{
+ unsigned long flags;
+ 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_irqsave(&xtime_lock, flags);
+
+ nsec -= __get_nsec_offset();
+
+ 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_irqrestore(&xtime_lock, flags);
+
+ /* signal hrtimers about time change */
+ clock_was_set();
+
+ return 0;
+}
+
+EXPORT_SYMBOL(do_settimeofday);
+
+/**
+ * change_clocksource - Swaps clocksources if a new one is available
+ *
+ * Accumulates current time interval and initializes new clocksource
+ */
+static int change_clocksource(void)
+{
+ struct clocksource *new;
+ cycle_t now;
+ u64 nsec;
+ new = get_next_clocksource();
+ if (clock != new) {
+ now = read_clocksource(new);
+ nsec = __get_nsec_offset();
+ timespec_add_ns(&xtime, nsec);
+
+ clock = new;
+ last_clock_cycle = now;
+ printk(KERN_INFO "Time: %s clocksource has been installed.\n",
+ clock->name);
+ return 1;
+ } else if (clock->update_callback) {
+ return clock->update_callback();
+ }
+ return 0;
+}
+#else
+#define change_clocksource() (0)
+#endif
+
+/**
+ * timeofday_is_continuous - check to see if timekeeping is free running
+ */
+int timekeeping_is_continuous(void)
+{
+ unsigned long seq;
+ int ret;
+
+ do {
+ seq = read_seqbegin(&xtime_lock);
+
+ ret = clock->is_continuous;
+
+ } while (read_seqretry(&xtime_lock, seq));
+
+ return ret;
+}
+
/*
* timekeeping_init - Initializes the clocksource and common timekeeping values
*/
@@ -912,6 +1075,13 @@ static void update_wall_time(void)
/* store full nanoseconds into xtime */
xtime.tv_nsec = remainder_snsecs >> clock->shift;
remainder_snsecs -= (s64)xtime.tv_nsec << clock->shift;
+
+ /* check to see if there is a new clocksource to use */
+ if (change_clocksource()) {
+ error = 0;
+ remainder_snsecs = 0;
+ calculate_clocksource_interval(clock, tick_nsec);
+ }
}
/*
This converts the i386 arch to use the generic timeofday
subsystem. It enabled the GENERIC_TIME option, disables the timer_opts
code and other arch specific timekeeping code and reworks the delay
code.
While this patch enables the generic timekeeping, please note that this
patch does not provide any i386 clocksource. Thus only the jiffies
clocksource will be available. To get full replacements for the code
being disabled here, the timeofday-clocks-i386 patch will needed.
thanks
-john
Signed-off-by: John Stultz <[email protected]>
arch/i386/Kconfig | 4 +
arch/i386/kernel/Makefile | 1
arch/i386/kernel/time.c | 153 +++++-----------------------------------------
arch/i386/kernel/tsc.c | 3
arch/i386/lib/delay.c | 65 +++++++++++++++++--
include/asm-i386/delay.h | 2
include/asm-i386/timer.h | 57 -----------------
7 files changed, 84 insertions(+), 201 deletions(-)
linux-2.6.16_timeofday-arch-i386-part3_C1.patch
============================================
diff --git a/arch/i386/Kconfig b/arch/i386/Kconfig
index 5b1a7d4..5f125f4 100644
--- a/arch/i386/Kconfig
+++ b/arch/i386/Kconfig
@@ -14,6 +14,10 @@ config X86_32
486, 586, Pentiums, and various instruction-set-compatible chips by
AMD, Cyrix, and others.
+config GENERIC_TIME
+ bool
+ default y
+
config SEMAPHORE_SLEEPERS
bool
default y
diff --git a/arch/i386/kernel/Makefile b/arch/i386/kernel/Makefile
index 16a2420..1477e69 100644
--- a/arch/i386/kernel/Makefile
+++ b/arch/i386/kernel/Makefile
@@ -10,7 +10,6 @@ obj-y := process.o semaphore.o signal.o
quirks.o i8237.o i8253.o tsc.o topology.o
obj-y += cpu/
-obj-y += timers/
obj-y += acpi/
obj-$(CONFIG_X86_BIOS_REBOOT) += reboot.o
obj-$(CONFIG_MCA) += mca.o
diff --git a/arch/i386/kernel/time.c b/arch/i386/kernel/time.c
index 796e5fa..2a6ab86 100644
--- a/arch/i386/kernel/time.c
+++ b/arch/i386/kernel/time.c
@@ -82,7 +82,8 @@ extern unsigned long wall_jiffies;
DEFINE_SPINLOCK(rtc_lock);
EXPORT_SYMBOL(rtc_lock);
-struct timer_opts *cur_timer __read_mostly = &timer_none;
+/* XXX - necessary to keep things compiling. to be removed later */
+u32 pmtmr_ioport;
/*
* This is a special lock that is owned by the CPU and holds the index
@@ -113,99 +114,19 @@ void rtc_cmos_write(unsigned char val, u
}
EXPORT_SYMBOL(rtc_cmos_write);
-/*
- * This version of gettimeofday has microsecond resolution
- * and better than microsecond precision on fast x86 machines with TSC.
- */
-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 = cur_timer->get_offset();
- 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 -= cur_timer->get_offset() * 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);
-
static int set_rtc_mmss(unsigned long nowtime)
{
int retval;
-
- WARN_ON(irqs_disabled());
+ unsigned long flags;
/* gets recalled with irq locally disabled */
- spin_lock_irq(&rtc_lock);
+ /* XXX - does irqsave resolve this? -johnstul */
+ spin_lock_irqsave(&rtc_lock, flags);
if (efi_enabled)
retval = efi_set_rtc_mmss(nowtime);
else
retval = mach_set_rtc_mmss(nowtime);
- spin_unlock_irq(&rtc_lock);
+ spin_unlock_irqrestore(&rtc_lock, flags);
return retval;
}
@@ -213,16 +134,6 @@ static int set_rtc_mmss(unsigned long no
int timer_ack;
-/* monotonic_clock(): returns # of nanoseconds passed since time_init()
- * Note: This function is required to return accurate
- * time even in the absence of multiple timer ticks.
- */
-unsigned long long monotonic_clock(void)
-{
- return cur_timer->monotonic_clock();
-}
-EXPORT_SYMBOL(monotonic_clock);
-
#if defined(CONFIG_SMP) && defined(CONFIG_FRAME_POINTER)
unsigned long profile_pc(struct pt_regs *regs)
{
@@ -237,11 +148,21 @@ EXPORT_SYMBOL(profile_pc);
#endif
/*
- * timer_interrupt() needs to keep up the real-time clock,
- * as well as call the "do_timer()" routine every clocktick
+ * This is the same as the above, except we _also_ save the current
+ * Time Stamp Counter value at the time of the timer interrupt, so that
+ * we later on can estimate the time of day more exactly.
*/
-static inline void do_timer_interrupt(int irq, struct pt_regs *regs)
+irqreturn_t timer_interrupt(int irq, void *dev_id, struct pt_regs *regs)
{
+ /*
+ * Here we are in the timer irq handler. We just have irqs locally
+ * disabled but we don't know if the timer_bh is running on the other
+ * CPU. We need to avoid to SMP race with it. NOTE: we don' t need
+ * the irq version of write_lock because as just said we have irq
+ * locally disabled. -arca
+ */
+ write_seqlock(&xtime_lock);
+
#ifdef CONFIG_X86_IO_APIC
if (timer_ack) {
/*
@@ -274,27 +195,6 @@ static inline void do_timer_interrupt(in
irq = inb_p( 0x61 ); /* read the current state */
outb_p( irq|0x80, 0x61 ); /* reset the IRQ */
}
-}
-
-/*
- * This is the same as the above, except we _also_ save the current
- * Time Stamp Counter value at the time of the timer interrupt, so that
- * we later on can estimate the time of day more exactly.
- */
-irqreturn_t timer_interrupt(int irq, void *dev_id, struct pt_regs *regs)
-{
- /*
- * Here we are in the timer irq handler. We just have irqs locally
- * disabled but we don't know if the timer_bh is running on the other
- * CPU. We need to avoid to SMP race with it. NOTE: we don' t need
- * the irq version of write_lock because as just said we have irq
- * locally disabled. -arca
- */
- write_seqlock(&xtime_lock);
-
- cur_timer->mark_offset();
-
- do_timer_interrupt(irq, regs);
write_sequnlock(&xtime_lock);
@@ -375,7 +275,6 @@ void notify_arch_cmos_timer(void)
static long clock_cmos_diff, sleep_start;
-static struct timer_opts *last_timer;
static int timer_suspend(struct sys_device *dev, pm_message_t state)
{
/*
@@ -384,10 +283,6 @@ static int timer_suspend(struct sys_devi
clock_cmos_diff = -get_cmos_time();
clock_cmos_diff += get_seconds();
sleep_start = get_cmos_time();
- last_timer = cur_timer;
- cur_timer = &timer_none;
- if (last_timer->suspend)
- last_timer->suspend(state);
return 0;
}
@@ -410,10 +305,6 @@ static int timer_resume(struct sys_devic
jiffies_64 += sleep_length;
wall_jiffies += sleep_length;
write_sequnlock_irqrestore(&xtime_lock, flags);
- if (last_timer->resume)
- last_timer->resume();
- cur_timer = last_timer;
- last_timer = NULL;
touch_softlockup_watchdog();
return 0;
}
@@ -455,9 +346,6 @@ static void __init hpet_time_init(void)
printk("Using HPET for base-timer\n");
}
- cur_timer = select_timer();
- printk(KERN_INFO "Using %s for high-res timesource\n",cur_timer->name);
-
time_init_hook();
}
#endif
@@ -479,8 +367,5 @@ void __init time_init(void)
set_normalized_timespec(&wall_to_monotonic,
-xtime.tv_sec, -xtime.tv_nsec);
- cur_timer = select_timer();
- printk(KERN_INFO "Using %s for high-res timesource\n",cur_timer->name);
-
time_init_hook();
}
diff --git a/arch/i386/kernel/tsc.c b/arch/i386/kernel/tsc.c
index b1f588c..8a940b5 100644
--- a/arch/i386/kernel/tsc.c
+++ b/arch/i386/kernel/tsc.c
@@ -10,6 +10,7 @@
#include <linux/init.h>
#include <asm/tsc.h>
+#include <asm/delay.h>
#include <asm/io.h>
#include "mach_timer.h"
@@ -45,7 +46,6 @@ static int __init tsc_setup(char *str)
__setup("notsc", tsc_setup);
-
/*
* code to mark and check if the TSC is unstable
* due to cpufreq or due to unsynced TSCs
@@ -205,6 +205,7 @@ void tsc_init(void)
(unsigned long)cpu_khz % 1000);
set_cyc2ns_scale(cpu_khz);
+ use_tsc_delay();
}
#ifdef CONFIG_CPU_FREQ
diff --git a/arch/i386/lib/delay.c b/arch/i386/lib/delay.c
index c49a6ac..3c0714c 100644
--- a/arch/i386/lib/delay.c
+++ b/arch/i386/lib/delay.c
@@ -10,43 +10,92 @@
* we have to worry about.
*/
+#include <linux/module.h>
#include <linux/config.h>
#include <linux/sched.h>
#include <linux/delay.h>
-#include <linux/module.h>
+
#include <asm/processor.h>
#include <asm/delay.h>
#include <asm/timer.h>
#ifdef CONFIG_SMP
-#include <asm/smp.h>
+# include <asm/smp.h>
#endif
-extern struct timer_opts* timer;
+/* simple loop based delay: */
+static void delay_loop(unsigned long loops)
+{
+ int d0;
+
+ __asm__ __volatile__(
+ "\tjmp 1f\n"
+ ".align 16\n"
+ "1:\tjmp 2f\n"
+ ".align 16\n"
+ "2:\tdecl %0\n\tjns 2b"
+ :"=&a" (d0)
+ :"0" (loops));
+}
+
+/* TSC based delay: */
+static void delay_tsc(unsigned long loops)
+{
+ unsigned long bclock, now;
+
+ rdtscl(bclock);
+ do {
+ rep_nop();
+ rdtscl(now);
+ } while ((now-bclock) < loops);
+}
+
+/*
+ * Since we calibrate only once at boot, this
+ * function should be set once at boot and not changed
+ */
+static void (*delay_fn)(unsigned long) = delay_loop;
+
+void use_tsc_delay(void)
+{
+ delay_fn = delay_tsc;
+}
+
+int read_current_timer(unsigned long *timer_val)
+{
+ if (delay_fn == delay_tsc) {
+ rdtscl(*timer_val);
+ return 0;
+ }
+ return -1;
+}
void __delay(unsigned long loops)
{
- cur_timer->delay(loops);
+ delay_fn(loops);
}
inline void __const_udelay(unsigned long xloops)
{
int d0;
+
xloops *= 4;
__asm__("mull %0"
:"=d" (xloops), "=&a" (d0)
- :"1" (xloops),"0" (cpu_data[raw_smp_processor_id()].loops_per_jiffy * (HZ/4)));
- __delay(++xloops);
+ :"1" (xloops), "0"
+ (cpu_data[raw_smp_processor_id()].loops_per_jiffy * (HZ/4)));
+
+ __delay(++xloops);
}
void __udelay(unsigned long usecs)
{
- __const_udelay(usecs * 0x000010c7); /* 2**32 / 1000000 (rounded up) */
+ __const_udelay(usecs * 0x000010c7); /* 2**32 / 1000000 (rounded up) */
}
void __ndelay(unsigned long nsecs)
{
- __const_udelay(nsecs * 0x00005); /* 2**32 / 1000000000 (rounded up) */
+ __const_udelay(nsecs * 0x00005); /* 2**32 / 1000000000 (rounded up) */
}
EXPORT_SYMBOL(__delay);
diff --git a/include/asm-i386/delay.h b/include/asm-i386/delay.h
index 456db85..b1c7650 100644
--- a/include/asm-i386/delay.h
+++ b/include/asm-i386/delay.h
@@ -23,4 +23,6 @@ extern void __delay(unsigned long loops)
((n) > 20000 ? __bad_ndelay() : __const_udelay((n) * 5ul)) : \
__ndelay(n))
+void use_tsc_delay(void);
+
#endif /* defined(_I386_DELAY_H) */
diff --git a/include/asm-i386/timer.h b/include/asm-i386/timer.h
index aed1643..d0ebd05 100644
--- a/include/asm-i386/timer.h
+++ b/include/asm-i386/timer.h
@@ -3,68 +3,11 @@
#include <linux/init.h>
#include <linux/pm.h>
-/**
- * struct timer_ops - used to define a timer source
- *
- * @name: name of the timer.
- * @init: Probes and initializes the timer. Takes clock= override
- * string as an argument. Returns 0 on success, anything else
- * on failure.
- * @mark_offset: called by the timer interrupt.
- * @get_offset: called by gettimeofday(). Returns the number of microseconds
- * since the last timer interupt.
- * @monotonic_clock: returns the number of nanoseconds since the init of the
- * timer.
- * @delay: delays this many clock cycles.
- */
-struct timer_opts {
- char* name;
- void (*mark_offset)(void);
- unsigned long (*get_offset)(void);
- unsigned long long (*monotonic_clock)(void);
- void (*delay)(unsigned long);
- unsigned long (*read_timer)(void);
- int (*suspend)(pm_message_t state);
- int (*resume)(void);
-};
-
-struct init_timer_opts {
- int (*init)(char *override);
- struct timer_opts *opts;
-};
-
#define TICK_SIZE (tick_nsec / 1000)
-
-extern struct timer_opts* __init select_timer(void);
-extern void clock_fallback(void);
void setup_pit_timer(void);
-
/* Modifiers for buggy PIT handling */
-
extern int pit_latch_buggy;
-
-extern struct timer_opts *cur_timer;
extern int timer_ack;
-
-/* list of externed timers */
-extern struct timer_opts timer_none;
-extern struct timer_opts timer_pit;
-extern struct init_timer_opts timer_pit_init;
-extern struct init_timer_opts timer_tsc_init;
-#ifdef CONFIG_X86_CYCLONE_TIMER
-extern struct init_timer_opts timer_cyclone_init;
-#endif
-
-extern unsigned long calibrate_tsc(void);
-extern unsigned long read_timer_tsc(void);
-extern void init_cpu_khz(void);
extern int recalibrate_cpu_khz(void);
-#ifdef CONFIG_HPET_TIMER
-extern struct init_timer_opts timer_hpet_init;
-extern unsigned long calibrate_tsc_hpet(unsigned long *tsc_hpet_quotient_ptr);
-#endif
-#ifdef CONFIG_X86_PM_TIMER
-extern struct init_timer_opts timer_pmtmr_init;
-#endif
#endif
This patch modifies the update_wall_time function so it
increments time using the clocksource abstraction instead of jiffies.
Since the only clocksource driver currently provided is the jiffies
clocksource, this should result in no functional change. Additionally,
a timekeeping_init and timekeeping_resume function has been added to
initialize and maintain some of the new timekeping state.
Signed-off-by John Stultz <[email protected]>
include/linux/time.h | 2 +
init/main.c | 1
kernel/Makefile | 1
kernel/timer.c | 93 +++++++++++++++++++++++++++++++++++++++++++--------
4 files changed, 84 insertions(+), 13 deletions(-)
linux-2.6.16_timeofday-core1_C1.patch
============================================
diff --git a/include/linux/time.h b/include/linux/time.h
index d9cdba5..84cfa7b 100644
--- a/include/linux/time.h
+++ b/include/linux/time.h
@@ -83,6 +83,8 @@ extern struct timespec xtime;
extern struct timespec wall_to_monotonic;
extern seqlock_t xtime_lock;
+void timekeeping_init(void);
+
static inline unsigned long get_seconds(void)
{
return xtime.tv_sec;
diff --git a/init/main.c b/init/main.c
index 4c194c4..b26d42d 100644
--- a/init/main.c
+++ b/init/main.c
@@ -486,6 +486,7 @@ asmlinkage void __init start_kernel(void
hrtimers_init();
softirq_init();
time_init();
+ timekeeping_init();
/*
* HACK ALERT! This is early. We're enabling the console before
diff --git a/kernel/Makefile b/kernel/Makefile
index 4ae0fbd..219bbad 100644
--- a/kernel/Makefile
+++ b/kernel/Makefile
@@ -10,6 +10,7 @@ obj-y = sched.o fork.o exec_domain.o
kthread.o wait.o kfifo.o sys_ni.o posix-cpu-timers.o mutex.o \
hrtimer.o
+obj-y += time/
obj-$(CONFIG_DEBUG_MUTEXES) += mutex-debug.o
obj-$(CONFIG_FUTEX) += futex.o
obj-$(CONFIG_GENERIC_ISA_DMA) += dma.o
diff --git a/kernel/timer.c b/kernel/timer.c
index 2410c18..78a9d03 100644
--- a/kernel/timer.c
+++ b/kernel/timer.c
@@ -803,24 +803,93 @@ u64 current_tick_length(void)
return ((u64) delta_nsec << (SHIFT_SCALE - 10)) + time_adj;
}
+/* XXX - all of this timekeeping code should be later moved to time.c */
+#include <linux/clocksource.h>
+static struct clocksource *clock; /* pointer to current clocksource */
+static cycle_t last_clock_cycle; /* cycle value at last update_wall_time */
/*
- * Using a loop looks inefficient, but "ticks" is
- * usually just one (we shouldn't be losing ticks,
- * we're doing this this way mainly for interrupt
- * latency reasons, not because we think we'll
- * have lots of lost timer ticks
+ * timekeeping_init - Initializes the clocksource and common timekeeping values
*/
-static void update_wall_time(unsigned long ticks)
+void timekeeping_init(void)
{
- do {
- ticks--;
+ unsigned long flags;
+
+ write_seqlock_irqsave(&xtime_lock, flags);
+ clock = get_next_clocksource();
+ calculate_clocksource_interval(clock, tick_nsec);
+ last_clock_cycle = read_clocksource(clock);
+ ntp_clear();
+ write_sequnlock_irqrestore(&xtime_lock, flags);
+}
+
+
+/*
+ * timekeeping_resume - Resumes the generic timekeeping subsystem.
+ * @dev: unused
+ *
+ * This is for the generic clocksource timekeeping.
+ * xtime/wall_to_monotonic/jiffies/wall_jiffies/etc are
+ * still managed by arch specific suspend/resume code.
+ */
+static int timekeeping_resume(struct sys_device *dev)
+{
+ unsigned long flags;
+
+ write_seqlock_irqsave(&xtime_lock, flags);
+ /* restart the last cycle value */
+ last_clock_cycle = read_clocksource(clock);
+ write_sequnlock_irqrestore(&xtime_lock, flags);
+ return 0;
+}
+
+/* sysfs resume/suspend bits for timekeeping */
+static struct sysdev_class timekeeping_sysclass = {
+ .resume = timekeeping_resume,
+ set_kset_name("timekeeping"),
+};
+
+static struct sys_device device_timer = {
+ .id = 0,
+ .cls = &timekeeping_sysclass,
+};
+
+static int timekeeping_init_device(void)
+{
+ int error = sysdev_class_register(&timekeeping_sysclass);
+ if (!error)
+ error = sysdev_register(&device_timer);
+ return error;
+}
+
+device_initcall(timekeeping_init_device);
+
+/*
+ * update_wall_time - Uses the current clocksource to increment the wall time
+ *
+ * Called from the timer interrupt, must hold a write on xtime_lock.
+ */
+static void update_wall_time(void)
+{
+ cycle_t now, offset;
+
+ now = read_clocksource(clock);
+ offset = (now - last_clock_cycle)&clock->mask;
+
+ /* normally this loop will run just once, however in the
+ * case of lost or late ticks, it will accumulate correctly.
+ */
+ while (offset > clock->interval_cycles) {
+ /* accumulate one interval */
+ last_clock_cycle += clock->interval_cycles;
+ offset -= clock->interval_cycles;
+
update_wall_time_one_tick();
if (xtime.tv_nsec >= 1000000000) {
xtime.tv_nsec -= 1000000000;
xtime.tv_sec++;
second_overflow();
}
- } while (ticks);
+ }
}
/*
@@ -925,10 +994,8 @@ static inline void update_times(void)
unsigned long ticks;
ticks = jiffies - wall_jiffies;
- if (ticks) {
- wall_jiffies += ticks;
- update_wall_time(ticks);
- }
+ wall_jiffies += ticks;
+ update_wall_time();
calc_load(ticks);
}
This patch implements the time sources for i386 (acpi_pm,
cyclone, hpet, pit, and tsc). With this patch, the conversion of the
i386 arch to the generic timekeeping code should be complete.
The patch should be fairly straight forward, only adding the new
clocksources.
thanks
-john
Signed-off-by: John Stultz <[email protected]>
Signed-off-by: Adrian Bunk <[email protected]>
Signed-off-by: Paul Mundt <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>
Signed-off-by: John Stultz <[email protected]>
arch/i386/kernel/Makefile | 1
arch/i386/kernel/hpet.c | 67 +++++++++++++++++
arch/i386/kernel/i8253.c | 53 +++++++++++++
arch/i386/kernel/time.c | 3
arch/i386/kernel/tsc.c | 161 ++++++++++++++++++++++++++++++++++++++++++
drivers/Makefile | 1
drivers/clocksource/Makefile | 2
drivers/clocksource/acpi_pm.c | 89 +++++++++++++++++++++++
drivers/clocksource/cyclone.c | 119 +++++++++++++++++++++++++++++++
kernel/time/clocksource.c | 9 +-
10 files changed, 500 insertions(+), 5 deletions(-)
linux-2.6.16_timeofday-clocks-i386_C1.patch
============================================
diff --git a/arch/i386/kernel/Makefile b/arch/i386/kernel/Makefile
index 1477e69..3a6a01c 100644
--- a/arch/i386/kernel/Makefile
+++ b/arch/i386/kernel/Makefile
@@ -36,6 +36,7 @@ obj-$(CONFIG_EFI) += efi.o efi_stub.o
obj-$(CONFIG_DOUBLEFAULT) += doublefault.o
obj-$(CONFIG_VM86) += vm86.o
obj-$(CONFIG_EARLY_PRINTK) += early_printk.o
+obj-$(CONFIG_HPET_TIMER) += hpet.o
EXTRA_AFLAGS := -traditional
diff --git a/arch/i386/kernel/hpet.c b/arch/i386/kernel/hpet.c
new file mode 100644
index 0000000..91a5bdd
--- /dev/null
+++ b/arch/i386/kernel/hpet.c
@@ -0,0 +1,67 @@
+#include <linux/clocksource.h>
+#include <linux/errno.h>
+#include <linux/hpet.h>
+#include <linux/init.h>
+
+#include <asm/hpet.h>
+#include <asm/io.h>
+
+#define HPET_MASK 0xFFFFFFFF
+#define HPET_SHIFT 22
+
+/* FSEC = 10^-15 NSEC = 10^-9 */
+#define FSEC_PER_NSEC 1000000
+
+static void *hpet_ptr;
+
+static cycle_t read_hpet(void)
+{
+ return (cycle_t)readl(hpet_ptr);
+}
+
+static struct clocksource clocksource_hpet = {
+ .name = "hpet",
+ .rating = 250,
+ .read = read_hpet,
+ .mask = (cycle_t)HPET_MASK,
+ .mult = 0, /* set below */
+ .shift = HPET_SHIFT,
+ .is_continuous = 1,
+};
+
+static int __init init_hpet_clocksource(void)
+{
+ unsigned long hpet_period;
+ void __iomem* hpet_base;
+ u64 tmp;
+
+ if (!hpet_address)
+ return -ENODEV;
+
+ /* calculate the hpet address: */
+ hpet_base =
+ (void __iomem*)ioremap_nocache(hpet_address, HPET_MMAP_SIZE);
+ hpet_ptr = hpet_base + HPET_COUNTER;
+
+ /* calculate the frequency: */
+ hpet_period = readl(hpet_base + HPET_PERIOD);
+
+ /*
+ * hpet period is in femto seconds per cycle
+ * so we need to convert this to ns/cyc units
+ * aproximated by mult/2^shift
+ *
+ * fsec/cyc * 1nsec/1000000fsec = nsec/cyc = mult/2^shift
+ * fsec/cyc * 1ns/1000000fsec * 2^shift = mult
+ * fsec/cyc * 2^shift * 1nsec/1000000fsec = mult
+ * (fsec/cyc << shift)/1000000 = mult
+ * (hpet_period << shift)/FSEC_PER_NSEC = mult
+ */
+ tmp = (u64)hpet_period << HPET_SHIFT;
+ do_div(tmp, FSEC_PER_NSEC);
+ clocksource_hpet.mult = (u32)tmp;
+
+ return register_clocksource(&clocksource_hpet);
+}
+
+module_init(init_hpet_clocksource);
diff --git a/arch/i386/kernel/i8253.c b/arch/i386/kernel/i8253.c
index 29cb2eb..a276bce 100644
--- a/arch/i386/kernel/i8253.c
+++ b/arch/i386/kernel/i8253.c
@@ -2,6 +2,7 @@
* i8253.c 8253/PIT functions
*
*/
+#include <linux/clocksource.h>
#include <linux/spinlock.h>
#include <linux/jiffies.h>
#include <linux/sysdev.h>
@@ -30,3 +31,55 @@ void setup_pit_timer(void)
outb(LATCH >> 8 , PIT_CH0); /* MSB */
spin_unlock_irqrestore(&i8253_lock, flags);
}
+
+/*
+ * Since the PIT overflows every tick, its not very useful
+ * to just read by itself. So use jiffies to emulate a free
+ * running counter:
+ */
+static cycle_t pit_read(void)
+{
+ unsigned long flags;
+ int count;
+ u64 jifs;
+
+ spin_lock_irqsave(&i8253_lock, flags);
+ outb_p(0x00, PIT_MODE); /* latch the count ASAP */
+ count = inb_p(PIT_CH0); /* read the latched count */
+ count |= inb_p(PIT_CH0) << 8;
+
+ /* VIA686a test code... reset the latch if count > max + 1 */
+ if (count > LATCH) {
+ outb_p(0x34, PIT_MODE);
+ outb_p(LATCH & 0xff, PIT_CH0);
+ outb(LATCH >> 8, PIT_CH0);
+ count = LATCH - 1;
+ }
+ spin_unlock_irqrestore(&i8253_lock, flags);
+
+ jifs = jiffies_64;
+
+ jifs -= INITIAL_JIFFIES;
+ count = (LATCH-1) - count;
+
+ return (cycle_t)(jifs * LATCH) + count;
+}
+
+static struct clocksource clocksource_pit = {
+ .name = "pit",
+ .rating = 110,
+ .read = pit_read,
+ .mask = (cycle_t)-1,
+ .mult = 0,
+ .shift = 20,
+};
+
+static int __init init_pit_clocksource(void)
+{
+ if (num_possible_cpus() > 4) /* PIT does not scale! */
+ return 0;
+
+ clocksource_pit.mult = clocksource_hz2mult(CLOCK_TICK_RATE, 20);
+ return register_clocksource(&clocksource_pit);
+}
+module_init(init_pit_clocksource);
diff --git a/arch/i386/kernel/time.c b/arch/i386/kernel/time.c
index 2a6ab86..5f43d04 100644
--- a/arch/i386/kernel/time.c
+++ b/arch/i386/kernel/time.c
@@ -82,9 +82,6 @@ extern unsigned long wall_jiffies;
DEFINE_SPINLOCK(rtc_lock);
EXPORT_SYMBOL(rtc_lock);
-/* XXX - necessary to keep things compiling. to be removed later */
-u32 pmtmr_ioport;
-
/*
* This is a special lock that is owned by the CPU and holds the index
* register we are working with. It is required for NMI access to the
diff --git a/arch/i386/kernel/tsc.c b/arch/i386/kernel/tsc.c
index 8a940b5..eb5fa83 100644
--- a/arch/i386/kernel/tsc.c
+++ b/arch/i386/kernel/tsc.c
@@ -4,11 +4,14 @@
* See comments there for proper credits.
*/
+#include <linux/clocksource.h>
#include <linux/workqueue.h>
#include <linux/cpufreq.h>
#include <linux/jiffies.h>
#include <linux/init.h>
+#include <linux/dmi.h>
+#include <asm/delay.h>
#include <asm/tsc.h>
#include <asm/delay.h>
#include <asm/io.h>
@@ -315,3 +318,161 @@ static int __init cpufreq_tsc(void)
core_initcall(cpufreq_tsc);
#endif
+
+/* clock source code */
+
+static unsigned long current_tsc_khz = 0;
+static int tsc_update_callback(void);
+
+static cycle_t read_tsc(void)
+{
+ cycle_t ret;
+
+ rdtscll(ret);
+
+ return ret;
+}
+
+static struct clocksource clocksource_tsc = {
+ .name = "tsc",
+ .rating = 300,
+ .read = read_tsc,
+ .mask = (cycle_t)-1,
+ .mult = 0, /* to be set */
+ .shift = 22,
+ .update_callback = tsc_update_callback,
+ .is_continuous = 1,
+};
+
+static int tsc_update_callback(void)
+{
+ int change = 0;
+
+ /* check to see if we should switch to the safe clocksource: */
+ if (clocksource_tsc.rating != 50 && check_tsc_unstable()) {
+ clocksource_tsc.rating = 50;
+ reselect_clocksource();
+ change = 1;
+ }
+
+ /* only update if tsc_khz has changed: */
+ if (current_tsc_khz != tsc_khz) {
+ current_tsc_khz = tsc_khz;
+ clocksource_tsc.mult = clocksource_khz2mult(current_tsc_khz,
+ clocksource_tsc.shift);
+ change = 1;
+ }
+
+ return change;
+}
+
+static int __init dmi_mark_tsc_unstable(struct dmi_system_id *d)
+{
+ printk(KERN_NOTICE "%s detected: marking TSC unstable.\n",
+ d->ident);
+ mark_tsc_unstable();
+ return 0;
+}
+
+/* List of systems that have known TSC problems */
+static struct dmi_system_id __initdata bad_tsc_dmi_table[] = {
+ {
+ .callback = dmi_mark_tsc_unstable,
+ .ident = "IBM Thinkpad 380XD",
+ .matches = {
+ DMI_MATCH(DMI_BOARD_VENDOR, "IBM"),
+ DMI_MATCH(DMI_BOARD_NAME, "2635FA0"),
+ },
+ },
+ {}
+};
+
+#define TSC_FREQ_CHECK_INTERVAL (10*MSEC_PER_SEC) /* 10sec in MS */
+static struct timer_list verfiy_tsc_freq_timer;
+
+/* XXX - Probably should add locking */
+static void verify_tsc_freq(unsigned long unused)
+{
+ static u64 last_tsc;
+ static unsigned long last_jiffies;
+
+ u64 now_tsc, interval_tsc;
+ unsigned long now_jiffies, interval_jiffies;
+
+
+ if (check_tsc_unstable())
+ return;
+
+ rdtscll(now_tsc);
+ now_jiffies = jiffies;
+
+ if (!last_jiffies) {
+ goto out;
+ }
+
+ interval_jiffies = now_jiffies - last_jiffies;
+ interval_tsc = now_tsc - last_tsc;
+ interval_tsc *= HZ;
+ do_div(interval_tsc, cpu_khz*1000);
+
+ if (interval_tsc < (interval_jiffies * 3 / 4)) {
+ printk("TSC appears to be running slowly. "
+ "Marking it as unstable\n");
+ mark_tsc_unstable();
+ return;
+ }
+
+out:
+ last_tsc = now_tsc;
+ last_jiffies = now_jiffies;
+ /* set us up to go off on the next interval: */
+ mod_timer(&verfiy_tsc_freq_timer,
+ jiffies + msecs_to_jiffies(TSC_FREQ_CHECK_INTERVAL));
+}
+
+/*
+ * Make an educated guess if the TSC is trustworthy and synchronized
+ * over all CPUs.
+ */
+static __init int unsynchronized_tsc(void)
+{
+ /*
+ * Intel systems are normally all synchronized.
+ * Exceptions must mark TSC as unstable:
+ */
+ if (boot_cpu_data.x86_vendor == X86_VENDOR_INTEL)
+ return 0;
+
+ /* assume multi socket systems are not synchronized: */
+ return num_possible_cpus() > 1;
+}
+
+static int __init init_tsc_clocksource(void)
+{
+
+ if (cpu_has_tsc && tsc_khz && !tsc_disable) {
+ /* check blacklist */
+ dmi_check_system(bad_tsc_dmi_table);
+
+ if (unsynchronized_tsc()) /* mark unstable if unsynced */
+ mark_tsc_unstable();
+ current_tsc_khz = tsc_khz;
+ clocksource_tsc.mult = clocksource_khz2mult(current_tsc_khz,
+ clocksource_tsc.shift);
+ /* lower the rating if we already know its unstable: */
+ if (check_tsc_unstable())
+ clocksource_tsc.rating = 50;
+
+ init_timer(&verfiy_tsc_freq_timer);
+ verfiy_tsc_freq_timer.function = verify_tsc_freq;
+ verfiy_tsc_freq_timer.expires =
+ jiffies + msecs_to_jiffies(TSC_FREQ_CHECK_INTERVAL);
+ add_timer(&verfiy_tsc_freq_timer);
+
+ return register_clocksource(&clocksource_tsc);
+ }
+
+ return 0;
+}
+
+module_init(init_tsc_clocksource);
diff --git a/drivers/Makefile b/drivers/Makefile
index 5c69b86..55df79e 100644
--- a/drivers/Makefile
+++ b/drivers/Makefile
@@ -73,3 +73,4 @@ obj-$(CONFIG_SGI_SN) += sn/
obj-y += firmware/
obj-$(CONFIG_CRYPTO) += crypto/
obj-$(CONFIG_SUPERH) += sh/
+obj-$(CONFIG_GENERIC_TIME) += clocksource/
diff --git a/drivers/clocksource/Makefile b/drivers/clocksource/Makefile
new file mode 100644
index 0000000..be3511a
--- /dev/null
+++ b/drivers/clocksource/Makefile
@@ -0,0 +1,2 @@
+obj-$(CONFIG_X86_CYCLONE_TIMER) += cyclone.o
+obj-$(CONFIG_X86_PM_TIMER) += acpi_pm.o
diff --git a/drivers/clocksource/acpi_pm.c b/drivers/clocksource/acpi_pm.c
new file mode 100644
index 0000000..5440206
--- /dev/null
+++ b/drivers/clocksource/acpi_pm.c
@@ -0,0 +1,89 @@
+/*
+ * linux/drivers/clocksource/acpi_pm.c
+ *
+ * This file contains the ACPI PM based clocksource.
+ *
+ * This code was largely moved from the i386 timer_pm.c file
+ * which was (C) Dominik Brodowski <[email protected]> 2003
+ * and contained the following comments:
+ *
+ * Driver to use the Power Management Timer (PMTMR) available in some
+ * southbridges as primary timing source for the Linux kernel.
+ *
+ * Based on parts of linux/drivers/acpi/hardware/hwtimer.c, timer_pit.c,
+ * timer_hpet.c, and on Arjan van de Ven's implementation for 2.4.
+ *
+ * This file is licensed under the GPL v2.
+ */
+
+#include <linux/clocksource.h>
+#include <linux/errno.h>
+#include <linux/init.h>
+#include <asm/io.h>
+
+/* Number of PMTMR ticks expected during calibration run */
+#define PMTMR_TICKS_PER_SEC 3579545
+
+/*
+ * The I/O port the PMTMR resides at.
+ * The location is detected during setup_arch(),
+ * in arch/i386/acpi/boot.c
+ */
+u32 pmtmr_ioport;
+
+#define ACPI_PM_MASK 0xFFFFFF /* limit it to 24 bits */
+
+static inline u32 read_pmtmr(void)
+{
+ /* mask the output to 24 bits */
+ return inl(pmtmr_ioport) & ACPI_PM_MASK;
+}
+
+static cycle_t acpi_pm_read(void)
+{
+ return (cycle_t)read_pmtmr();
+}
+
+static struct clocksource clocksource_acpi_pm = {
+ .name = "acpi_pm",
+ .rating = 200,
+ .read = acpi_pm_read,
+ .mask = (cycle_t)ACPI_PM_MASK,
+ .mult = 0, /*to be caluclated*/
+ .shift = 22,
+ .is_continuous = 1,
+};
+
+static int __init init_acpi_pm_clocksource(void)
+{
+ u32 value1, value2;
+ unsigned int i;
+
+ if (!pmtmr_ioport)
+ return -ENODEV;
+
+ clocksource_acpi_pm.mult = clocksource_hz2mult(PMTMR_TICKS_PER_SEC,
+ clocksource_acpi_pm.shift);
+
+ /* "verify" this timing source: */
+ value1 = read_pmtmr();
+ for (i = 0; i < 10000; i++) {
+ value2 = read_pmtmr();
+ if (value2 == value1)
+ continue;
+ if (value2 > value1)
+ goto pm_good;
+ if ((value2 < value1) && ((value2) < 0xFFF))
+ goto pm_good;
+ printk(KERN_INFO "PM-Timer had inconsistent results: 0x%#x, 0x%#x - aborting.\n", value1, value2);
+ return -EINVAL;
+ }
+ printk(KERN_INFO "PM-Timer had no reasonable result: 0x%#x - aborting.\n", value1);
+ return -ENODEV;
+
+pm_good:
+
+ return register_clocksource(&clocksource_acpi_pm);
+}
+
+module_init(init_acpi_pm_clocksource);
diff --git a/drivers/clocksource/cyclone.c b/drivers/clocksource/cyclone.c
new file mode 100644
index 0000000..444eb11
--- /dev/null
+++ b/drivers/clocksource/cyclone.c
@@ -0,0 +1,119 @@
+#include <linux/clocksource.h>
+#include <linux/string.h>
+#include <linux/errno.h>
+#include <linux/timex.h>
+#include <linux/init.h>
+
+#include <asm/pgtable.h>
+#include <asm/io.h>
+
+#include "mach_timer.h"
+
+#define CYCLONE_CBAR_ADDR 0xFEB00CD0 /* base address ptr */
+#define CYCLONE_PMCC_OFFSET 0x51A0 /* offset to control register */
+#define CYCLONE_MPCS_OFFSET 0x51A8 /* offset to select register */
+#define CYCLONE_MPMC_OFFSET 0x51D0 /* offset to count register */
+#define CYCLONE_TIMER_FREQ 99780000 /* 100Mhz, but not really */
+#define CYCLONE_TIMER_MASK 0xFFFFFFFF /* 32 bit mask */
+
+int use_cyclone = 0;
+static void __iomem *cyclone_ptr;
+
+static cycle_t read_cyclone(void)
+{
+ return (cycle_t)readl(cyclone_ptr);
+}
+
+static struct clocksource clocksource_cyclone = {
+ .name = "cyclone",
+ .rating = 250,
+ .read = read_cyclone,
+ .mask = (cycle_t)CYCLONE_TIMER_MASK,
+ .mult = 10,
+ .shift = 0,
+ .is_continuous = 1,
+};
+
+static int __init init_cyclone_clocksource(void)
+{
+ unsigned long base; /* saved value from CBAR */
+ unsigned long offset;
+ u32 __iomem* volatile cyclone_timer; /* Cyclone MPMC0 register */
+ u32 __iomem* reg;
+ int i;
+
+ /* make sure we're on a summit box: */
+ if (!use_cyclone)
+ return -ENODEV;
+
+ printk(KERN_INFO "Summit chipset: Starting Cyclone Counter.\n");
+
+ /* find base address: */
+ offset = CYCLONE_CBAR_ADDR;
+ reg = ioremap_nocache(offset, sizeof(reg));
+ if (!reg) {
+ printk(KERN_ERR "Summit chipset: Could not find valid CBAR register.\n");
+ return -ENODEV;
+ }
+ /* even on 64bit systems, this is only 32bits: */
+ base = readl(reg);
+ if (!base) {
+ printk(KERN_ERR "Summit chipset: Could not find valid CBAR value.\n");
+ return -ENODEV;
+ }
+ iounmap(reg);
+
+ /* setup PMCC: */
+ offset = base + CYCLONE_PMCC_OFFSET;
+ reg = ioremap_nocache(offset, sizeof(reg));
+ if (!reg) {
+ printk(KERN_ERR "Summit chipset: Could not find valid PMCC register.\n");
+ return -ENODEV;
+ }
+ writel(0x00000001,reg);
+ iounmap(reg);
+
+ /* setup MPCS: */
+ offset = base + CYCLONE_MPCS_OFFSET;
+ reg = ioremap_nocache(offset, sizeof(reg));
+ if (!reg) {
+ printk(KERN_ERR "Summit chipset: Could not find valid MPCS register.\n");
+ return -ENODEV;
+ }
+ writel(0x00000001,reg);
+ iounmap(reg);
+
+ /* map in cyclone_timer: */
+ offset = base + CYCLONE_MPMC_OFFSET;
+ cyclone_timer = ioremap_nocache(offset, sizeof(u64));
+ if (!cyclone_timer) {
+ printk(KERN_ERR "Summit chipset: Could not find valid MPMC register.\n");
+ return -ENODEV;
+ }
+
+ /* quick test to make sure its ticking: */
+ for (i = 0; i < 3; i++){
+ u32 old = readl(cyclone_timer);
+ int stall = 100;
+
+ while (stall--)
+ barrier();
+
+ if (readl(cyclone_timer) == old) {
+ printk(KERN_ERR "Summit chipset: Counter not counting! DISABLED\n");
+ iounmap(cyclone_timer);
+ cyclone_timer = NULL;
+ return -ENODEV;
+ }
+ }
+ cyclone_ptr = cyclone_timer;
+
+ /* sort out mult/shift values: */
+ clocksource_cyclone.shift = 22;
+ clocksource_cyclone.mult = clocksource_hz2mult(CYCLONE_TIMER_FREQ,
+ clocksource_cyclone.shift);
+
+ return register_clocksource(&clocksource_cyclone);
+}
+
+module_init(init_cyclone_clocksource);
diff --git a/kernel/time/clocksource.c b/kernel/time/clocksource.c
index 954a61f..68c6aaf 100644
--- a/kernel/time/clocksource.c
+++ b/kernel/time/clocksource.c
@@ -335,8 +335,13 @@ __setup("clocksource=", boot_override_cl
*/
static int __init boot_override_clock(char* str)
{
- printk("Warning! clock= boot option is deprecated.\n");
-
+ if (!strcmp(str, "pmtmr")) {
+ printk("Warning: clock=pmtmr is depricated. "
+ "Use clocksource=acpi_pm.\n");
+ return boot_override_clocksource("acpi_pm");
+ }
+ printk("Warning! clock= boot option is deprecated. "
+ "Use clocksource=xyz\n");
return boot_override_clocksource(str);
}
As part of the i386 conversion to the generic timekeeping
infrastructure, this introduces a new tsc.c file. The code in this file
replaces the TSC initialization, management and access code currently
in timer_tsc.c (which will be removed) that we want to preserve.
The code also introduces the following functionality:
o tsc_khz: like cpu_khz but stores the TSC frequency on systems that do
not change TSC frequency w/ CPU frequency
o check/mark_tsc_unstable: accessor/modifier flag for TSC timekeeping
usability
o minor cleanups to calibration math.
This patch also includes a one line __cpuinitdata fix from Zwane
Mwaikambo.
thanks
-john
Signed-off-by: John Stultz <[email protected]>
arch/i386/kernel/Makefile | 2
arch/i386/kernel/numaq.c | 10
arch/i386/kernel/setup.c | 1
arch/i386/kernel/timers/timer_tsc.c | 178 ---------------
arch/i386/kernel/tsc.c | 316 ++++++++++++++++++++++++++++
drivers/acpi/processor_idle.c | 9
include/asm-i386/mach-default/mach_timer.h | 4
include/asm-i386/mach-summit/mach_mpparse.h | 3
include/asm-i386/timex.h | 34 ---
include/asm-i386/tsc.h | 49 ++++
10 files changed, 389 insertions(+), 217 deletions(-)
linux-2.6.16_timeofday-arch-i386-part2_C1.patch
============================================
diff --git a/arch/i386/kernel/Makefile b/arch/i386/kernel/Makefile
index 687a29b..16a2420 100644
--- a/arch/i386/kernel/Makefile
+++ b/arch/i386/kernel/Makefile
@@ -7,7 +7,7 @@ extra-y := head.o init_task.o vmlinux.ld
obj-y := process.o semaphore.o signal.o entry.o traps.o irq.o \
ptrace.o time.o ioport.o ldt.o setup.o i8259.o sys_i386.o \
pci-dma.o i386_ksyms.o i387.o dmi_scan.o bootflag.o \
- quirks.o i8237.o i8253.o topology.o
+ quirks.o i8237.o i8253.o tsc.o topology.o
obj-y += cpu/
obj-y += timers/
diff --git a/arch/i386/kernel/numaq.c b/arch/i386/kernel/numaq.c
index 5f5b075..0caf146 100644
--- a/arch/i386/kernel/numaq.c
+++ b/arch/i386/kernel/numaq.c
@@ -79,10 +79,12 @@ int __init get_memcfg_numaq(void)
return 1;
}
-static int __init numaq_dsc_disable(void)
+static int __init numaq_tsc_disable(void)
{
- printk(KERN_DEBUG "NUMAQ: disabling TSC\n");
- tsc_disable = 1;
+ if (num_online_nodes() > 1) {
+ printk(KERN_DEBUG "NUMAQ: disabling TSC\n");
+ tsc_disable = 1;
+ }
return 0;
}
-core_initcall(numaq_dsc_disable);
+arch_initcall(numaq_tsc_disable);
diff --git a/arch/i386/kernel/setup.c b/arch/i386/kernel/setup.c
index ab62a9f..1ac4963 100644
--- a/arch/i386/kernel/setup.c
+++ b/arch/i386/kernel/setup.c
@@ -1632,6 +1632,7 @@ void __init setup_arch(char **cmdline_p)
conswitchp = &dummy_con;
#endif
#endif
+ tsc_init();
}
#include "setup_arch_post.h"
diff --git a/arch/i386/kernel/timers/timer_tsc.c b/arch/i386/kernel/timers/timer_tsc.c
index 5e41ee2..243ec04 100644
--- a/arch/i386/kernel/timers/timer_tsc.c
+++ b/arch/i386/kernel/timers/timer_tsc.c
@@ -32,10 +32,6 @@ static unsigned long hpet_last;
static struct timer_opts timer_tsc;
#endif
-static inline void cpufreq_delayed_get(void);
-
-int tsc_disable __devinitdata = 0;
-
static int use_tsc;
/* Number of usecs that the last interrupt was delayed */
static int delay_at_last_interrupt;
@@ -144,30 +140,6 @@ static unsigned long long monotonic_cloc
return base + cycles_2_ns(this_offset - last_offset);
}
-/*
- * Scheduler clock - returns current time in nanosec units.
- */
-unsigned long long sched_clock(void)
-{
- unsigned long long this_offset;
-
- /*
- * In the NUMA case we dont use the TSC as they are not
- * synchronized across all CPUs.
- */
-#ifndef CONFIG_NUMA
- if (!use_tsc)
-#endif
- /* no locking but a rare wrong value is not a big deal */
- return jiffies_64 * (1000000000 / HZ);
-
- /* Read the Time Stamp Counter */
- rdtscll(this_offset);
-
- /* return the value in ns */
- return cycles_2_ns(this_offset);
-}
-
static void delay_tsc(unsigned long loops)
{
unsigned long bclock, now;
@@ -231,136 +203,6 @@ static void mark_offset_tsc_hpet(void)
}
#endif
-
-#ifdef CONFIG_CPU_FREQ
-#include <linux/workqueue.h>
-
-static unsigned int cpufreq_delayed_issched = 0;
-static unsigned int cpufreq_init = 0;
-static struct work_struct cpufreq_delayed_get_work;
-
-static void handle_cpufreq_delayed_get(void *v)
-{
- unsigned int cpu;
- for_each_online_cpu(cpu) {
- cpufreq_get(cpu);
- }
- cpufreq_delayed_issched = 0;
-}
-
-/* if we notice lost ticks, schedule a call to cpufreq_get() as it tries
- * to verify the CPU frequency the timing core thinks the CPU is running
- * at is still correct.
- */
-static inline void cpufreq_delayed_get(void)
-{
- if (cpufreq_init && !cpufreq_delayed_issched) {
- cpufreq_delayed_issched = 1;
- printk(KERN_DEBUG "Losing some ticks... checking if CPU frequency changed.\n");
- schedule_work(&cpufreq_delayed_get_work);
- }
-}
-
-/* If the CPU frequency is scaled, TSC-based delays will need a different
- * loops_per_jiffy value to function properly.
- */
-
-static unsigned int ref_freq = 0;
-static unsigned long loops_per_jiffy_ref = 0;
-
-#ifndef CONFIG_SMP
-static unsigned long fast_gettimeoffset_ref = 0;
-static unsigned int cpu_khz_ref = 0;
-#endif
-
-static int
-time_cpufreq_notifier(struct notifier_block *nb, unsigned long val,
- void *data)
-{
- struct cpufreq_freqs *freq = data;
-
- if (val != CPUFREQ_RESUMECHANGE)
- write_seqlock_irq(&xtime_lock);
- if (!ref_freq) {
- if (!freq->old){
- ref_freq = freq->new;
- goto end;
- }
- ref_freq = freq->old;
- loops_per_jiffy_ref = cpu_data[freq->cpu].loops_per_jiffy;
-#ifndef CONFIG_SMP
- fast_gettimeoffset_ref = fast_gettimeoffset_quotient;
- cpu_khz_ref = cpu_khz;
-#endif
- }
-
- if ((val == CPUFREQ_PRECHANGE && freq->old < freq->new) ||
- (val == CPUFREQ_POSTCHANGE && freq->old > freq->new) ||
- (val == CPUFREQ_RESUMECHANGE)) {
- if (!(freq->flags & CPUFREQ_CONST_LOOPS))
- cpu_data[freq->cpu].loops_per_jiffy = cpufreq_scale(loops_per_jiffy_ref, ref_freq, freq->new);
-#ifndef CONFIG_SMP
- if (cpu_khz)
- cpu_khz = cpufreq_scale(cpu_khz_ref, ref_freq, freq->new);
- if (use_tsc) {
- if (!(freq->flags & CPUFREQ_CONST_LOOPS)) {
- fast_gettimeoffset_quotient = cpufreq_scale(fast_gettimeoffset_ref, freq->new, ref_freq);
- set_cyc2ns_scale(cpu_khz);
- }
- }
-#endif
- }
-
-end:
- if (val != CPUFREQ_RESUMECHANGE)
- write_sequnlock_irq(&xtime_lock);
-
- return 0;
-}
-
-static struct notifier_block time_cpufreq_notifier_block = {
- .notifier_call = time_cpufreq_notifier
-};
-
-
-static int __init cpufreq_tsc(void)
-{
- int ret;
- INIT_WORK(&cpufreq_delayed_get_work, handle_cpufreq_delayed_get, NULL);
- ret = cpufreq_register_notifier(&time_cpufreq_notifier_block,
- CPUFREQ_TRANSITION_NOTIFIER);
- if (!ret)
- cpufreq_init = 1;
- return ret;
-}
-core_initcall(cpufreq_tsc);
-
-#else /* CONFIG_CPU_FREQ */
-static inline void cpufreq_delayed_get(void) { return; }
-#endif
-
-int recalibrate_cpu_khz(void)
-{
-#ifndef CONFIG_SMP
- unsigned int cpu_khz_old = cpu_khz;
-
- if (cpu_has_tsc) {
- local_irq_disable();
- init_cpu_khz();
- local_irq_enable();
- cpu_data[0].loops_per_jiffy =
- cpufreq_scale(cpu_data[0].loops_per_jiffy,
- cpu_khz_old,
- cpu_khz);
- return 0;
- } else
- return -ENODEV;
-#else
- return -ENODEV;
-#endif
-}
-EXPORT_SYMBOL(recalibrate_cpu_khz);
-
static void mark_offset_tsc(void)
{
unsigned long lost,delay;
@@ -451,9 +293,6 @@ static void mark_offset_tsc(void)
clock_fallback();
}
- /* ... but give the TSC a fair chance */
- if (lost_count > 25)
- cpufreq_delayed_get();
} else
lost_count = 0;
/* update the monotonic base value */
@@ -578,23 +417,6 @@ static int tsc_resume(void)
return 0;
}
-#ifndef CONFIG_X86_TSC
-/* disable flag for tsc. Takes effect by clearing the TSC cpu flag
- * in cpu/common.c */
-static int __init tsc_setup(char *str)
-{
- tsc_disable = 1;
- return 1;
-}
-#else
-static int __init tsc_setup(char *str)
-{
- printk(KERN_WARNING "notsc: Kernel compiled with CONFIG_X86_TSC, "
- "cannot disable TSC.\n");
- return 1;
-}
-#endif
-__setup("notsc", tsc_setup);
diff --git a/arch/i386/kernel/tsc.c b/arch/i386/kernel/tsc.c
new file mode 100644
index 0000000..b1f588c
--- /dev/null
+++ b/arch/i386/kernel/tsc.c
@@ -0,0 +1,316 @@
+/*
+ * This code largely moved from arch/i386/kernel/timer/timer_tsc.c
+ * which was originally moved from arch/i386/kernel/time.c.
+ * See comments there for proper credits.
+ */
+
+#include <linux/workqueue.h>
+#include <linux/cpufreq.h>
+#include <linux/jiffies.h>
+#include <linux/init.h>
+
+#include <asm/tsc.h>
+#include <asm/io.h>
+
+#include "mach_timer.h"
+
+/*
+ * On some systems the TSC frequency does not
+ * change with the cpu frequency. So we need
+ * an extra value to store the TSC freq
+ */
+unsigned int tsc_khz;
+
+int tsc_disable __cpuinitdata = 0;
+
+#ifdef CONFIG_X86_TSC
+static int __init tsc_setup(char *str)
+{
+ printk(KERN_WARNING "notsc: Kernel compiled with CONFIG_X86_TSC, "
+ "cannot disable TSC.\n");
+ return 1;
+}
+#else
+/*
+ * disable flag for tsc. Takes effect by clearing the TSC cpu flag
+ * in cpu/common.c
+ */
+static int __init tsc_setup(char *str)
+{
+ tsc_disable = 1;
+
+ return 1;
+}
+#endif
+
+__setup("notsc", tsc_setup);
+
+
+/*
+ * code to mark and check if the TSC is unstable
+ * due to cpufreq or due to unsynced TSCs
+ */
+static int tsc_unstable;
+
+static inline int check_tsc_unstable(void)
+{
+ return tsc_unstable;
+}
+
+void mark_tsc_unstable(void)
+{
+ tsc_unstable = 1;
+}
+EXPORT_SYMBOL_GPL(mark_tsc_unstable);
+
+/* Accellerators for sched_clock()
+ * convert from cycles(64bits) => nanoseconds (64bits)
+ * basic equation:
+ * ns = cycles / (freq / ns_per_sec)
+ * ns = cycles * (ns_per_sec / freq)
+ * ns = cycles * (10^9 / (cpu_khz * 10^3))
+ * ns = cycles * (10^6 / cpu_khz)
+ *
+ * Then we use scaling math (suggested by [email protected]) to get:
+ * ns = cycles * (10^6 * SC / cpu_khz) / SC
+ * ns = cycles * cyc2ns_scale / SC
+ *
+ * And since SC is a constant power of two, we can convert the div
+ * into a shift.
+ *
+ * We can use khz divisor instead of mhz to keep a better percision, since
+ * cyc2ns_scale is limited to 10^6 * 2^10, which fits in 32 bits.
+ * ([email protected])
+ *
+ * [email protected] "math is hard, lets go shopping!"
+ */
+static unsigned long cyc2ns_scale __read_mostly;
+
+#define CYC2NS_SCALE_FACTOR 10 /* 2^10, carefully chosen */
+
+static inline void set_cyc2ns_scale(unsigned long cpu_khz)
+{
+ cyc2ns_scale = (1000000 << CYC2NS_SCALE_FACTOR)/cpu_khz;
+}
+
+static inline unsigned long long cycles_2_ns(unsigned long long cyc)
+{
+ return (cyc * cyc2ns_scale) >> CYC2NS_SCALE_FACTOR;
+}
+
+/*
+ * Scheduler clock - returns current time in nanosec units.
+ */
+unsigned long long sched_clock(void)
+{
+ unsigned long long this_offset;
+
+ /*
+ * in the NUMA case we dont use the TSC as they are not
+ * synchronized across all CPUs.
+ */
+#ifndef CONFIG_NUMA
+ if (!cpu_khz || check_tsc_unstable())
+#endif
+ /* no locking but a rare wrong value is not a big deal */
+ return (jiffies_64 - INITIAL_JIFFIES) * (1000000000 / HZ);
+
+ /* read the Time Stamp Counter: */
+ rdtscll(this_offset);
+
+ /* return the value in ns */
+ return cycles_2_ns(this_offset);
+}
+
+static unsigned long calculate_cpu_khz(void)
+{
+ unsigned long long start, end;
+ unsigned long count;
+ u64 delta64;
+ int i;
+ unsigned long flags;
+
+ local_irq_save(flags);
+
+ /* run 3 times to ensure the cache is warm */
+ for (i = 0; i < 3; i++) {
+ mach_prepare_counter();
+ rdtscll(start);
+ mach_countup(&count);
+ rdtscll(end);
+ }
+ /*
+ * Error: ECTCNEVERSET
+ * The CTC wasn't reliable: we got a hit on the very first read,
+ * or the CPU was so fast/slow that the quotient wouldn't fit in
+ * 32 bits..
+ */
+ if (count <= 1)
+ goto err;
+
+ delta64 = end - start;
+
+ /* cpu freq too fast: */
+ if (delta64 > (1ULL<<32))
+ goto err;
+
+ /* cpu freq too slow: */
+ if (delta64 <= CALIBRATE_TIME_MSEC)
+ goto err;
+
+ delta64 += CALIBRATE_TIME_MSEC/2; /* round for do_div */
+ do_div(delta64,CALIBRATE_TIME_MSEC);
+
+ local_irq_restore(flags);
+ return (unsigned long)delta64;
+err:
+ local_irq_restore(flags);
+ return 0;
+}
+
+int recalibrate_cpu_khz(void)
+{
+#ifndef CONFIG_SMP
+ unsigned long cpu_khz_old = cpu_khz;
+
+ if (cpu_has_tsc) {
+ cpu_khz = calculate_cpu_khz();
+ tsc_khz = cpu_khz;
+ cpu_data[0].loops_per_jiffy =
+ cpufreq_scale(cpu_data[0].loops_per_jiffy,
+ cpu_khz_old, cpu_khz);
+ return 0;
+ } else
+ return -ENODEV;
+#else
+ return -ENODEV;
+#endif
+}
+
+EXPORT_SYMBOL(recalibrate_cpu_khz);
+
+void tsc_init(void)
+{
+ if (!cpu_has_tsc || tsc_disable)
+ return;
+
+ cpu_khz = calculate_cpu_khz();
+ tsc_khz = cpu_khz;
+
+ if (!cpu_khz)
+ return;
+
+ printk("Detected %lu.%03lu MHz processor.\n",
+ (unsigned long)cpu_khz / 1000,
+ (unsigned long)cpu_khz % 1000);
+
+ set_cyc2ns_scale(cpu_khz);
+}
+
+#ifdef CONFIG_CPU_FREQ
+
+static unsigned int cpufreq_delayed_issched = 0;
+static unsigned int cpufreq_init = 0;
+static struct work_struct cpufreq_delayed_get_work;
+
+static void handle_cpufreq_delayed_get(void *v)
+{
+ unsigned int cpu;
+
+ for_each_online_cpu(cpu)
+ cpufreq_get(cpu);
+
+ cpufreq_delayed_issched = 0;
+}
+
+/*
+ * if we notice cpufreq oddness, schedule a call to cpufreq_get() as it tries
+ * to verify the CPU frequency the timing core thinks the CPU is running
+ * at is still correct.
+ */
+static inline void cpufreq_delayed_get(void)
+{
+ if (cpufreq_init && !cpufreq_delayed_issched) {
+ cpufreq_delayed_issched = 1;
+ printk(KERN_DEBUG "Checking if CPU frequency changed.\n");
+ schedule_work(&cpufreq_delayed_get_work);
+ }
+}
+
+/*
+ * if the CPU frequency is scaled, TSC-based delays will need a different
+ * loops_per_jiffy value to function properly.
+ */
+static unsigned int ref_freq = 0;
+static unsigned long loops_per_jiffy_ref = 0;
+static unsigned long cpu_khz_ref = 0;
+
+static int
+time_cpufreq_notifier(struct notifier_block *nb, unsigned long val, void *data)
+{
+ struct cpufreq_freqs *freq = data;
+
+ if (val != CPUFREQ_RESUMECHANGE)
+ write_seqlock_irq(&xtime_lock);
+
+ if (!ref_freq) {
+ if (!freq->old){
+ ref_freq = freq->new;
+ goto end;
+ }
+ ref_freq = freq->old;
+ loops_per_jiffy_ref = cpu_data[freq->cpu].loops_per_jiffy;
+ cpu_khz_ref = cpu_khz;
+ }
+
+ if ((val == CPUFREQ_PRECHANGE && freq->old < freq->new) ||
+ (val == CPUFREQ_POSTCHANGE && freq->old > freq->new) ||
+ (val == CPUFREQ_RESUMECHANGE)) {
+ if (!(freq->flags & CPUFREQ_CONST_LOOPS))
+ cpu_data[freq->cpu].loops_per_jiffy =
+ cpufreq_scale(loops_per_jiffy_ref,
+ ref_freq, freq->new);
+
+ if (cpu_khz) {
+
+ if (num_online_cpus() == 1)
+ cpu_khz = cpufreq_scale(cpu_khz_ref,
+ ref_freq, freq->new);
+ if (!(freq->flags & CPUFREQ_CONST_LOOPS)) {
+ tsc_khz = cpu_khz;
+ set_cyc2ns_scale(cpu_khz);
+ /*
+ * TSC based sched_clock turns
+ * to junk w/ cpufreq
+ */
+ mark_tsc_unstable();
+ }
+ }
+ }
+end:
+ if (val != CPUFREQ_RESUMECHANGE)
+ write_sequnlock_irq(&xtime_lock);
+
+ return 0;
+}
+
+static struct notifier_block time_cpufreq_notifier_block = {
+ .notifier_call = time_cpufreq_notifier
+};
+
+static int __init cpufreq_tsc(void)
+{
+ int ret;
+
+ INIT_WORK(&cpufreq_delayed_get_work, handle_cpufreq_delayed_get, NULL);
+ ret = cpufreq_register_notifier(&time_cpufreq_notifier_block,
+ CPUFREQ_TRANSITION_NOTIFIER);
+ if (!ret)
+ cpufreq_init = 1;
+
+ return ret;
+}
+
+core_initcall(cpufreq_tsc);
+
+#endif
diff --git a/drivers/acpi/processor_idle.c b/drivers/acpi/processor_idle.c
index eb730a8..9a54eba 100644
--- a/drivers/acpi/processor_idle.c
+++ b/drivers/acpi/processor_idle.c
@@ -369,6 +369,11 @@ static void acpi_processor_idle(void)
t2 = inl(acpi_fadt.xpm_tmr_blk.address);
/* Get end time (ticks) */
t2 = inl(acpi_fadt.xpm_tmr_blk.address);
+
+#ifdef CONFIG_GENERIC_TIME
+ /* TSC halts in C2, so notify users */
+ mark_tsc_unstable();
+#endif
/* Re-enable interrupts */
local_irq_enable();
set_thread_flag(TIF_POLLING_NRFLAG);
@@ -409,6 +414,10 @@ static void acpi_processor_idle(void)
ACPI_MTX_DO_NOT_LOCK);
}
+#ifdef CONFIG_GENERIC_TIME
+ /* TSC halts in C3, so notify users */
+ mark_tsc_unstable();
+#endif
/* Re-enable interrupts */
local_irq_enable();
set_thread_flag(TIF_POLLING_NRFLAG);
diff --git a/include/asm-i386/mach-default/mach_timer.h b/include/asm-i386/mach-default/mach_timer.h
index 4b9703b..807992f 100644
--- a/include/asm-i386/mach-default/mach_timer.h
+++ b/include/asm-i386/mach-default/mach_timer.h
@@ -15,7 +15,9 @@
#ifndef _MACH_TIMER_H
#define _MACH_TIMER_H
-#define CALIBRATE_LATCH (5 * LATCH)
+#define CALIBRATE_TIME_MSEC 30 /* 30 msecs */
+#define CALIBRATE_LATCH \
+ ((CLOCK_TICK_RATE * CALIBRATE_TIME_MSEC + 1000/2)/1000)
static inline void mach_prepare_counter(void)
{
diff --git a/include/asm-i386/mach-summit/mach_mpparse.h b/include/asm-i386/mach-summit/mach_mpparse.h
index 1cce2b9..9426839 100644
--- a/include/asm-i386/mach-summit/mach_mpparse.h
+++ b/include/asm-i386/mach-summit/mach_mpparse.h
@@ -2,6 +2,7 @@
#define __ASM_MACH_MPPARSE_H
#include <mach_apic.h>
+#include <asm/tsc.h>
extern int use_cyclone;
@@ -29,6 +30,7 @@ static inline int mps_oem_check(struct m
(!strncmp(productid, "VIGIL SMP", 9)
|| !strncmp(productid, "EXA", 3)
|| !strncmp(productid, "RUTHLESS SMP", 12))){
+ mark_tsc_unstable();
use_cyclone = 1; /*enable cyclone-timer*/
setup_summit();
return 1;
@@ -42,6 +44,7 @@ static inline int acpi_madt_oem_check(ch
if (!strncmp(oem_id, "IBM", 3) &&
(!strncmp(oem_table_id, "SERVIGIL", 8)
|| !strncmp(oem_table_id, "EXA", 3))){
+ mark_tsc_unstable();
use_cyclone = 1; /*enable cyclone-timer*/
setup_summit();
return 1;
diff --git a/include/asm-i386/timex.h b/include/asm-i386/timex.h
index 292b5a6..ebcc74e 100644
--- a/include/asm-i386/timex.h
+++ b/include/asm-i386/timex.h
@@ -8,6 +8,7 @@
#include <linux/config.h>
#include <asm/processor.h>
+#include <asm/tsc.h>
#ifdef CONFIG_X86_ELAN
# define CLOCK_TICK_RATE 1189200 /* AMD Elan has different frequency! */
@@ -16,39 +17,6 @@
#endif
-/*
- * Standard way to access the cycle counter on i586+ CPUs.
- * Currently only used on SMP.
- *
- * If you really have a SMP machine with i486 chips or older,
- * compile for that, and this will just always return zero.
- * That's ok, it just means that the nicer scheduling heuristics
- * won't work for you.
- *
- * We only use the low 32 bits, and we'd simply better make sure
- * that we reschedule before that wraps. Scheduling at least every
- * four billion cycles just basically sounds like a good idea,
- * regardless of how fast the machine is.
- */
-typedef unsigned long long cycles_t;
-
-static inline cycles_t get_cycles (void)
-{
- unsigned long long ret=0;
-
-#ifndef CONFIG_X86_TSC
- if (!cpu_has_tsc)
- return 0;
-#endif
-
-#if defined(CONFIG_X86_GENERIC) || defined(CONFIG_X86_TSC)
- rdtscll(ret);
-#endif
- return ret;
-}
-
-extern unsigned int cpu_khz;
-
extern int read_current_timer(unsigned long *timer_value);
#define ARCH_HAS_READ_CURRENT_TIMER 1
diff --git a/include/asm-i386/tsc.h b/include/asm-i386/tsc.h
new file mode 100644
index 0000000..97b828c
--- /dev/null
+++ b/include/asm-i386/tsc.h
@@ -0,0 +1,49 @@
+/*
+ * linux/include/asm-i386/tsc.h
+ *
+ * i386 TSC related functions
+ */
+#ifndef _ASM_i386_TSC_H
+#define _ASM_i386_TSC_H
+
+#include <linux/config.h>
+#include <asm/processor.h>
+
+/*
+ * Standard way to access the cycle counter on i586+ CPUs.
+ * Currently only used on SMP.
+ *
+ * If you really have a SMP machine with i486 chips or older,
+ * compile for that, and this will just always return zero.
+ * That's ok, it just means that the nicer scheduling heuristics
+ * won't work for you.
+ *
+ * We only use the low 32 bits, and we'd simply better make sure
+ * that we reschedule before that wraps. Scheduling at least every
+ * four billion cycles just basically sounds like a good idea,
+ * regardless of how fast the machine is.
+ */
+typedef unsigned long long cycles_t;
+
+extern unsigned int cpu_khz;
+extern unsigned int tsc_khz;
+
+static inline cycles_t get_cycles(void)
+{
+ unsigned long long ret = 0;
+
+#ifndef CONFIG_X86_TSC
+ if (!cpu_has_tsc)
+ return 0;
+#endif
+
+#if defined(CONFIG_X86_GENERIC) || defined(CONFIG_X86_TSC)
+ rdtscll(ret);
+#endif
+ return ret;
+}
+
+extern void tsc_init(void);
+extern void mark_tsc_unstable(void);
+
+#endif
This patch removes the old timers/timer_opts infrastructure
which has been disabled. It is a fairly straightforward set of deletions
Note that this does not provide any i386 clocksources, so you will only
have the jiffies clocksource. To get full replacements for the code
being removed here, the timeofday-clocks-i386 patch will be needed.
thanks
-john
Signed-off-by: John Stultz <[email protected]>
Makefile | 9 -
common.c | 172 ---------------------
timer.c | 75 ---------
timer_cyclone.c | 259 ---------------------------------
timer_hpet.c | 217 ---------------------------
timer_none.c | 39 ----
timer_pit.c | 164 --------------------
timer_pm.c | 268 ----------------------------------
timer_tsc.c | 439 --------------------------------------------------------
9 files changed, 1642 deletions(-)
linux-2.6.16_timeofday-arch-i386-part4_C1.patch
============================================
diff --git a/arch/i386/kernel/timers/Makefile b/arch/i386/kernel/timers/Makefile
deleted file mode 100644
index 8fa12be..0000000
--- a/arch/i386/kernel/timers/Makefile
+++ /dev/null
@@ -1,9 +0,0 @@
-#
-# Makefile for x86 timers
-#
-
-obj-y := timer.o timer_none.o timer_tsc.o timer_pit.o common.o
-
-obj-$(CONFIG_X86_CYCLONE_TIMER) += timer_cyclone.o
-obj-$(CONFIG_HPET_TIMER) += timer_hpet.o
-obj-$(CONFIG_X86_PM_TIMER) += timer_pm.o
diff --git a/arch/i386/kernel/timers/common.c b/arch/i386/kernel/timers/common.c
deleted file mode 100644
index 8163fe0..0000000
--- a/arch/i386/kernel/timers/common.c
+++ /dev/null
@@ -1,172 +0,0 @@
-/*
- * Common functions used across the timers go here
- */
-
-#include <linux/init.h>
-#include <linux/timex.h>
-#include <linux/errno.h>
-#include <linux/jiffies.h>
-#include <linux/module.h>
-
-#include <asm/io.h>
-#include <asm/timer.h>
-#include <asm/hpet.h>
-
-#include "mach_timer.h"
-
-/* ------ Calibrate the TSC -------
- * Return 2^32 * (1 / (TSC clocks per usec)) for do_fast_gettimeoffset().
- * Too much 64-bit arithmetic here to do this cleanly in C, and for
- * accuracy's sake we want to keep the overhead on the CTC speaker (channel 2)
- * output busy loop as low as possible. We avoid reading the CTC registers
- * directly because of the awkward 8-bit access mechanism of the 82C54
- * device.
- */
-
-#define CALIBRATE_TIME (5 * 1000020/HZ)
-
-unsigned long calibrate_tsc(void)
-{
- mach_prepare_counter();
-
- {
- unsigned long startlow, starthigh;
- unsigned long endlow, endhigh;
- unsigned long count;
-
- rdtsc(startlow,starthigh);
- mach_countup(&count);
- rdtsc(endlow,endhigh);
-
-
- /* Error: ECTCNEVERSET */
- if (count <= 1)
- goto bad_ctc;
-
- /* 64-bit subtract - gcc just messes up with long longs */
- __asm__("subl %2,%0\n\t"
- "sbbl %3,%1"
- :"=a" (endlow), "=d" (endhigh)
- :"g" (startlow), "g" (starthigh),
- "0" (endlow), "1" (endhigh));
-
- /* Error: ECPUTOOFAST */
- if (endhigh)
- goto bad_ctc;
-
- /* Error: ECPUTOOSLOW */
- if (endlow <= CALIBRATE_TIME)
- goto bad_ctc;
-
- __asm__("divl %2"
- :"=a" (endlow), "=d" (endhigh)
- :"r" (endlow), "0" (0), "1" (CALIBRATE_TIME));
-
- return endlow;
- }
-
- /*
- * The CTC wasn't reliable: we got a hit on the very first read,
- * or the CPU was so fast/slow that the quotient wouldn't fit in
- * 32 bits..
- */
-bad_ctc:
- return 0;
-}
-
-#ifdef CONFIG_HPET_TIMER
-/* ------ Calibrate the TSC using HPET -------
- * Return 2^32 * (1 / (TSC clocks per usec)) for getting the CPU freq.
- * Second output is parameter 1 (when non NULL)
- * Set 2^32 * (1 / (tsc per HPET clk)) for delay_hpet().
- * calibrate_tsc() calibrates the processor TSC by comparing
- * it to the HPET timer of known frequency.
- * Too much 64-bit arithmetic here to do this cleanly in C
- */
-#define CALIBRATE_CNT_HPET (5 * hpet_tick)
-#define CALIBRATE_TIME_HPET (5 * KERNEL_TICK_USEC)
-
-unsigned long __devinit calibrate_tsc_hpet(unsigned long *tsc_hpet_quotient_ptr)
-{
- unsigned long tsc_startlow, tsc_starthigh;
- unsigned long tsc_endlow, tsc_endhigh;
- unsigned long hpet_start, hpet_end;
- unsigned long result, remain;
-
- hpet_start = hpet_readl(HPET_COUNTER);
- rdtsc(tsc_startlow, tsc_starthigh);
- do {
- hpet_end = hpet_readl(HPET_COUNTER);
- } while ((hpet_end - hpet_start) < CALIBRATE_CNT_HPET);
- rdtsc(tsc_endlow, tsc_endhigh);
-
- /* 64-bit subtract - gcc just messes up with long longs */
- __asm__("subl %2,%0\n\t"
- "sbbl %3,%1"
- :"=a" (tsc_endlow), "=d" (tsc_endhigh)
- :"g" (tsc_startlow), "g" (tsc_starthigh),
- "0" (tsc_endlow), "1" (tsc_endhigh));
-
- /* Error: ECPUTOOFAST */
- if (tsc_endhigh)
- goto bad_calibration;
-
- /* Error: ECPUTOOSLOW */
- if (tsc_endlow <= CALIBRATE_TIME_HPET)
- goto bad_calibration;
-
- ASM_DIV64_REG(result, remain, tsc_endlow, 0, CALIBRATE_TIME_HPET);
- if (remain > (tsc_endlow >> 1))
- result++; /* rounding the result */
-
- if (tsc_hpet_quotient_ptr) {
- unsigned long tsc_hpet_quotient;
-
- ASM_DIV64_REG(tsc_hpet_quotient, remain, tsc_endlow, 0,
- CALIBRATE_CNT_HPET);
- if (remain > (tsc_endlow >> 1))
- tsc_hpet_quotient++; /* rounding the result */
- *tsc_hpet_quotient_ptr = tsc_hpet_quotient;
- }
-
- return result;
-bad_calibration:
- /*
- * the CPU was so fast/slow that the quotient wouldn't fit in
- * 32 bits..
- */
- return 0;
-}
-#endif
-
-
-unsigned long read_timer_tsc(void)
-{
- unsigned long retval;
- rdtscl(retval);
- return retval;
-}
-
-
-/* calculate cpu_khz */
-void init_cpu_khz(void)
-{
- if (cpu_has_tsc) {
- unsigned long tsc_quotient = calibrate_tsc();
- if (tsc_quotient) {
- /* report CPU clock rate in Hz.
- * The formula is (10^6 * 2^32) / (2^32 * 1 / (clocks/us)) =
- * clock/second. Our precision is about 100 ppm.
- */
- { unsigned long eax=0, edx=1000;
- __asm__("divl %2"
- :"=a" (cpu_khz), "=d" (edx)
- :"r" (tsc_quotient),
- "0" (eax), "1" (edx));
- printk("Detected %u.%03u MHz processor.\n",
- cpu_khz / 1000, cpu_khz % 1000);
- }
- }
- }
-}
-
diff --git a/arch/i386/kernel/timers/timer.c b/arch/i386/kernel/timers/timer.c
deleted file mode 100644
index 7e39ed8..0000000
--- a/arch/i386/kernel/timers/timer.c
+++ /dev/null
@@ -1,75 +0,0 @@
-#include <linux/init.h>
-#include <linux/kernel.h>
-#include <linux/string.h>
-#include <asm/timer.h>
-
-#ifdef CONFIG_HPET_TIMER
-/*
- * HPET memory read is slower than tsc reads, but is more dependable as it
- * always runs at constant frequency and reduces complexity due to
- * cpufreq. So, we prefer HPET timer to tsc based one. Also, we cannot use
- * timer_pit when HPET is active. So, we default to timer_tsc.
- */
-#endif
-/* list of timers, ordered by preference, NULL terminated */
-static struct init_timer_opts* __initdata timers[] = {
-#ifdef CONFIG_X86_CYCLONE_TIMER
- &timer_cyclone_init,
-#endif
-#ifdef CONFIG_HPET_TIMER
- &timer_hpet_init,
-#endif
-#ifdef CONFIG_X86_PM_TIMER
- &timer_pmtmr_init,
-#endif
- &timer_tsc_init,
- &timer_pit_init,
- NULL,
-};
-
-static char clock_override[10] __initdata;
-
-static int __init clock_setup(char* str)
-{
- if (str)
- strlcpy(clock_override, str, sizeof(clock_override));
- return 1;
-}
-__setup("clock=", clock_setup);
-
-
-/* The chosen timesource has been found to be bad.
- * Fall back to a known good timesource (the PIT)
- */
-void clock_fallback(void)
-{
- cur_timer = &timer_pit;
-}
-
-/* iterates through the list of timers, returning the first
- * one that initializes successfully.
- */
-struct timer_opts* __init select_timer(void)
-{
- int i = 0;
-
- /* find most preferred working timer */
- while (timers[i]) {
- if (timers[i]->init)
- if (timers[i]->init(clock_override) == 0)
- return timers[i]->opts;
- ++i;
- }
-
- panic("select_timer: Cannot find a suitable timer\n");
- return NULL;
-}
-
-int read_current_timer(unsigned long *timer_val)
-{
- if (cur_timer->read_timer) {
- *timer_val = cur_timer->read_timer();
- return 0;
- }
- return -1;
-}
diff --git a/arch/i386/kernel/timers/timer_cyclone.c b/arch/i386/kernel/timers/timer_cyclone.c
deleted file mode 100644
index 13892a6..0000000
--- a/arch/i386/kernel/timers/timer_cyclone.c
+++ /dev/null
@@ -1,259 +0,0 @@
-/* Cyclone-timer:
- * This code implements timer_ops for the cyclone counter found
- * on IBM x440, x360, and other Summit based systems.
- *
- * Copyright (C) 2002 IBM, John Stultz ([email protected])
- */
-
-
-#include <linux/spinlock.h>
-#include <linux/init.h>
-#include <linux/timex.h>
-#include <linux/errno.h>
-#include <linux/string.h>
-#include <linux/jiffies.h>
-
-#include <asm/timer.h>
-#include <asm/io.h>
-#include <asm/pgtable.h>
-#include <asm/fixmap.h>
-#include <asm/i8253.h>
-
-#include "io_ports.h"
-
-/* Number of usecs that the last interrupt was delayed */
-static int delay_at_last_interrupt;
-
-#define CYCLONE_CBAR_ADDR 0xFEB00CD0
-#define CYCLONE_PMCC_OFFSET 0x51A0
-#define CYCLONE_MPMC_OFFSET 0x51D0
-#define CYCLONE_MPCS_OFFSET 0x51A8
-#define CYCLONE_TIMER_FREQ 100000000
-#define CYCLONE_TIMER_MASK (((u64)1<<40)-1) /* 40 bit mask */
-int use_cyclone = 0;
-
-static u32* volatile cyclone_timer; /* Cyclone MPMC0 register */
-static u32 last_cyclone_low;
-static u32 last_cyclone_high;
-static unsigned long long monotonic_base;
-static seqlock_t monotonic_lock = SEQLOCK_UNLOCKED;
-
-/* helper macro to atomically read both cyclone counter registers */
-#define read_cyclone_counter(low,high) \
- do{ \
- high = cyclone_timer[1]; low = cyclone_timer[0]; \
- } while (high != cyclone_timer[1]);
-
-
-static void mark_offset_cyclone(void)
-{
- unsigned long lost, delay;
- unsigned long delta = last_cyclone_low;
- int count;
- unsigned long long this_offset, last_offset;
-
- write_seqlock(&monotonic_lock);
- last_offset = ((unsigned long long)last_cyclone_high<<32)|last_cyclone_low;
-
- spin_lock(&i8253_lock);
- read_cyclone_counter(last_cyclone_low,last_cyclone_high);
-
- /* read values for delay_at_last_interrupt */
- outb_p(0x00, 0x43); /* latch the count ASAP */
-
- count = inb_p(0x40); /* read the latched count */
- count |= inb(0x40) << 8;
-
- /*
- * VIA686a test code... reset the latch if count > max + 1
- * from timer_pit.c - cjb
- */
- if (count > LATCH) {
- outb_p(0x34, PIT_MODE);
- outb_p(LATCH & 0xff, PIT_CH0);
- outb(LATCH >> 8, PIT_CH0);
- count = LATCH - 1;
- }
- spin_unlock(&i8253_lock);
-
- /* lost tick compensation */
- delta = last_cyclone_low - delta;
- delta /= (CYCLONE_TIMER_FREQ/1000000);
- delta += delay_at_last_interrupt;
- lost = delta/(1000000/HZ);
- delay = delta%(1000000/HZ);
- if (lost >= 2)
- jiffies_64 += lost-1;
-
- /* update the monotonic base value */
- this_offset = ((unsigned long long)last_cyclone_high<<32)|last_cyclone_low;
- monotonic_base += (this_offset - last_offset) & CYCLONE_TIMER_MASK;
- write_sequnlock(&monotonic_lock);
-
- /* calculate delay_at_last_interrupt */
- count = ((LATCH-1) - count) * TICK_SIZE;
- delay_at_last_interrupt = (count + LATCH/2) / LATCH;
-
-
- /* catch corner case where tick rollover occured
- * between cyclone and pit reads (as noted when
- * usec delta is > 90% # of usecs/tick)
- */
- if (lost && abs(delay - delay_at_last_interrupt) > (900000/HZ))
- jiffies_64++;
-}
-
-static unsigned long get_offset_cyclone(void)
-{
- u32 offset;
-
- if(!cyclone_timer)
- return delay_at_last_interrupt;
-
- /* Read the cyclone timer */
- offset = cyclone_timer[0];
-
- /* .. relative to previous jiffy */
- offset = offset - last_cyclone_low;
-
- /* convert cyclone ticks to microseconds */
- /* XXX slow, can we speed this up? */
- offset = offset/(CYCLONE_TIMER_FREQ/1000000);
-
- /* our adjusted time offset in microseconds */
- return delay_at_last_interrupt + offset;
-}
-
-static unsigned long long monotonic_clock_cyclone(void)
-{
- u32 now_low, now_high;
- unsigned long long last_offset, this_offset, base;
- unsigned long long ret;
- unsigned seq;
-
- /* atomically read monotonic base & last_offset */
- do {
- seq = read_seqbegin(&monotonic_lock);
- last_offset = ((unsigned long long)last_cyclone_high<<32)|last_cyclone_low;
- base = monotonic_base;
- } while (read_seqretry(&monotonic_lock, seq));
-
-
- /* Read the cyclone counter */
- read_cyclone_counter(now_low,now_high);
- this_offset = ((unsigned long long)now_high<<32)|now_low;
-
- /* convert to nanoseconds */
- ret = base + ((this_offset - last_offset)&CYCLONE_TIMER_MASK);
- return ret * (1000000000 / CYCLONE_TIMER_FREQ);
-}
-
-static int __init init_cyclone(char* override)
-{
- u32* reg;
- u32 base; /* saved cyclone base address */
- u32 pageaddr; /* page that contains cyclone_timer register */
- u32 offset; /* offset from pageaddr to cyclone_timer register */
- int i;
-
- /* check clock override */
- if (override[0] && strncmp(override,"cyclone",7))
- return -ENODEV;
-
- /*make sure we're on a summit box*/
- if(!use_cyclone) return -ENODEV;
-
- printk(KERN_INFO "Summit chipset: Starting Cyclone Counter.\n");
-
- /* find base address */
- pageaddr = (CYCLONE_CBAR_ADDR)&PAGE_MASK;
- offset = (CYCLONE_CBAR_ADDR)&(~PAGE_MASK);
- set_fixmap_nocache(FIX_CYCLONE_TIMER, pageaddr);
- reg = (u32*)(fix_to_virt(FIX_CYCLONE_TIMER) + offset);
- if(!reg){
- printk(KERN_ERR "Summit chipset: Could not find valid CBAR register.\n");
- return -ENODEV;
- }
- base = *reg;
- if(!base){
- printk(KERN_ERR "Summit chipset: Could not find valid CBAR value.\n");
- return -ENODEV;
- }
-
- /* setup PMCC */
- pageaddr = (base + CYCLONE_PMCC_OFFSET)&PAGE_MASK;
- offset = (base + CYCLONE_PMCC_OFFSET)&(~PAGE_MASK);
- set_fixmap_nocache(FIX_CYCLONE_TIMER, pageaddr);
- reg = (u32*)(fix_to_virt(FIX_CYCLONE_TIMER) + offset);
- if(!reg){
- printk(KERN_ERR "Summit chipset: Could not find valid PMCC register.\n");
- return -ENODEV;
- }
- reg[0] = 0x00000001;
-
- /* setup MPCS */
- pageaddr = (base + CYCLONE_MPCS_OFFSET)&PAGE_MASK;
- offset = (base + CYCLONE_MPCS_OFFSET)&(~PAGE_MASK);
- set_fixmap_nocache(FIX_CYCLONE_TIMER, pageaddr);
- reg = (u32*)(fix_to_virt(FIX_CYCLONE_TIMER) + offset);
- if(!reg){
- printk(KERN_ERR "Summit chipset: Could not find valid MPCS register.\n");
- return -ENODEV;
- }
- reg[0] = 0x00000001;
-
- /* map in cyclone_timer */
- pageaddr = (base + CYCLONE_MPMC_OFFSET)&PAGE_MASK;
- offset = (base + CYCLONE_MPMC_OFFSET)&(~PAGE_MASK);
- set_fixmap_nocache(FIX_CYCLONE_TIMER, pageaddr);
- cyclone_timer = (u32*)(fix_to_virt(FIX_CYCLONE_TIMER) + offset);
- if(!cyclone_timer){
- printk(KERN_ERR "Summit chipset: Could not find valid MPMC register.\n");
- return -ENODEV;
- }
-
- /*quick test to make sure its ticking*/
- for(i=0; i<3; i++){
- u32 old = cyclone_timer[0];
- int stall = 100;
- while(stall--) barrier();
- if(cyclone_timer[0] == old){
- printk(KERN_ERR "Summit chipset: Counter not counting! DISABLED\n");
- cyclone_timer = 0;
- return -ENODEV;
- }
- }
-
- init_cpu_khz();
-
- /* Everything looks good! */
- return 0;
-}
-
-
-static void delay_cyclone(unsigned long loops)
-{
- unsigned long bclock, now;
- if(!cyclone_timer)
- return;
- bclock = cyclone_timer[0];
- do {
- rep_nop();
- now = cyclone_timer[0];
- } while ((now-bclock) < loops);
-}
-/************************************************************/
-
-/* cyclone timer_opts struct */
-static struct timer_opts timer_cyclone = {
- .name = "cyclone",
- .mark_offset = mark_offset_cyclone,
- .get_offset = get_offset_cyclone,
- .monotonic_clock = monotonic_clock_cyclone,
- .delay = delay_cyclone,
-};
-
-struct init_timer_opts __initdata timer_cyclone_init = {
- .init = init_cyclone,
- .opts = &timer_cyclone,
-};
diff --git a/arch/i386/kernel/timers/timer_hpet.c b/arch/i386/kernel/timers/timer_hpet.c
deleted file mode 100644
index 17a6fe7..0000000
--- a/arch/i386/kernel/timers/timer_hpet.c
+++ /dev/null
@@ -1,217 +0,0 @@
-/*
- * This code largely moved from arch/i386/kernel/time.c.
- * See comments there for proper credits.
- */
-
-#include <linux/spinlock.h>
-#include <linux/init.h>
-#include <linux/timex.h>
-#include <linux/errno.h>
-#include <linux/string.h>
-#include <linux/jiffies.h>
-
-#include <asm/timer.h>
-#include <asm/io.h>
-#include <asm/processor.h>
-
-#include "io_ports.h"
-#include "mach_timer.h"
-#include <asm/hpet.h>
-
-static unsigned long hpet_usec_quotient __read_mostly; /* convert hpet clks to usec */
-static unsigned long tsc_hpet_quotient __read_mostly; /* convert tsc to hpet clks */
-static unsigned long hpet_last; /* hpet counter value at last tick*/
-static unsigned long last_tsc_low; /* lsb 32 bits of Time Stamp Counter */
-static unsigned long last_tsc_high; /* msb 32 bits of Time Stamp Counter */
-static unsigned long long monotonic_base;
-static seqlock_t monotonic_lock = SEQLOCK_UNLOCKED;
-
-/* convert from cycles(64bits) => nanoseconds (64bits)
- * basic equation:
- * ns = cycles / (freq / ns_per_sec)
- * ns = cycles * (ns_per_sec / freq)
- * ns = cycles * (10^9 / (cpu_khz * 10^3))
- * ns = cycles * (10^6 / cpu_khz)
- *
- * Then we use scaling math (suggested by [email protected]) to get:
- * ns = cycles * (10^6 * SC / cpu_khz) / SC
- * ns = cycles * cyc2ns_scale / SC
- *
- * And since SC is a constant power of two, we can convert the div
- * into a shift.
- *
- * We can use khz divisor instead of mhz to keep a better percision, since
- * cyc2ns_scale is limited to 10^6 * 2^10, which fits in 32 bits.
- * ([email protected])
- *
- * [email protected] "math is hard, lets go shopping!"
- */
-static unsigned long cyc2ns_scale __read_mostly;
-#define CYC2NS_SCALE_FACTOR 10 /* 2^10, carefully chosen */
-
-static inline void set_cyc2ns_scale(unsigned long cpu_khz)
-{
- cyc2ns_scale = (1000000 << CYC2NS_SCALE_FACTOR)/cpu_khz;
-}
-
-static inline unsigned long long cycles_2_ns(unsigned long long cyc)
-{
- return (cyc * cyc2ns_scale) >> CYC2NS_SCALE_FACTOR;
-}
-
-static unsigned long long monotonic_clock_hpet(void)
-{
- unsigned long long last_offset, this_offset, base;
- unsigned seq;
-
- /* atomically read monotonic base & last_offset */
- do {
- seq = read_seqbegin(&monotonic_lock);
- last_offset = ((unsigned long long)last_tsc_high<<32)|last_tsc_low;
- base = monotonic_base;
- } while (read_seqretry(&monotonic_lock, seq));
-
- /* Read the Time Stamp Counter */
- rdtscll(this_offset);
-
- /* return the value in ns */
- return base + cycles_2_ns(this_offset - last_offset);
-}
-
-static unsigned long get_offset_hpet(void)
-{
- register unsigned long eax, edx;
-
- eax = hpet_readl(HPET_COUNTER);
- eax -= hpet_last; /* hpet delta */
- eax = min(hpet_tick, eax);
- /*
- * Time offset = (hpet delta) * ( usecs per HPET clock )
- * = (hpet delta) * ( usecs per tick / HPET clocks per tick)
- * = (hpet delta) * ( hpet_usec_quotient ) / (2^32)
- *
- * Where,
- * hpet_usec_quotient = (2^32 * usecs per tick)/HPET clocks per tick
- *
- * Using a mull instead of a divl saves some cycles in critical path.
- */
- ASM_MUL64_REG(eax, edx, hpet_usec_quotient, eax);
-
- /* our adjusted time offset in microseconds */
- return edx;
-}
-
-static void mark_offset_hpet(void)
-{
- unsigned long long this_offset, last_offset;
- unsigned long offset;
-
- write_seqlock(&monotonic_lock);
- last_offset = ((unsigned long long)last_tsc_high<<32)|last_tsc_low;
- rdtsc(last_tsc_low, last_tsc_high);
-
- if (hpet_use_timer)
- offset = hpet_readl(HPET_T0_CMP) - hpet_tick;
- else
- offset = hpet_readl(HPET_COUNTER);
- if (unlikely(((offset - hpet_last) >= (2*hpet_tick)) && (hpet_last != 0))) {
- int lost_ticks = ((offset - hpet_last) / hpet_tick) - 1;
- jiffies_64 += lost_ticks;
- }
- hpet_last = offset;
-
- /* update the monotonic base value */
- this_offset = ((unsigned long long)last_tsc_high<<32)|last_tsc_low;
- monotonic_base += cycles_2_ns(this_offset - last_offset);
- write_sequnlock(&monotonic_lock);
-}
-
-static void delay_hpet(unsigned long loops)
-{
- unsigned long hpet_start, hpet_end;
- unsigned long eax;
-
- /* loops is the number of cpu cycles. Convert it to hpet clocks */
- ASM_MUL64_REG(eax, loops, tsc_hpet_quotient, loops);
-
- hpet_start = hpet_readl(HPET_COUNTER);
- do {
- rep_nop();
- hpet_end = hpet_readl(HPET_COUNTER);
- } while ((hpet_end - hpet_start) < (loops));
-}
-
-static struct timer_opts timer_hpet;
-
-static int __init init_hpet(char* override)
-{
- unsigned long result, remain;
-
- /* check clock override */
- if (override[0] && strncmp(override,"hpet",4))
- return -ENODEV;
-
- if (!is_hpet_enabled())
- return -ENODEV;
-
- printk("Using HPET for gettimeofday\n");
- if (cpu_has_tsc) {
- unsigned long tsc_quotient = calibrate_tsc_hpet(&tsc_hpet_quotient);
- if (tsc_quotient) {
- /* report CPU clock rate in Hz.
- * The formula is (10^6 * 2^32) / (2^32 * 1 / (clocks/us)) =
- * clock/second. Our precision is about 100 ppm.
- */
- { unsigned long eax=0, edx=1000;
- ASM_DIV64_REG(cpu_khz, edx, tsc_quotient,
- eax, edx);
- printk("Detected %u.%03u MHz processor.\n",
- cpu_khz / 1000, cpu_khz % 1000);
- }
- set_cyc2ns_scale(cpu_khz);
- }
- /* set this only when cpu_has_tsc */
- timer_hpet.read_timer = read_timer_tsc;
- }
-
- /*
- * Math to calculate hpet to usec multiplier
- * Look for the comments at get_offset_hpet()
- */
- ASM_DIV64_REG(result, remain, hpet_tick, 0, KERNEL_TICK_USEC);
- if (remain > (hpet_tick >> 1))
- result++; /* rounding the result */
- hpet_usec_quotient = result;
-
- return 0;
-}
-
-static int hpet_resume(void)
-{
- write_seqlock(&monotonic_lock);
- /* Assume this is the last mark offset time */
- rdtsc(last_tsc_low, last_tsc_high);
-
- if (hpet_use_timer)
- hpet_last = hpet_readl(HPET_T0_CMP) - hpet_tick;
- else
- hpet_last = hpet_readl(HPET_COUNTER);
- write_sequnlock(&monotonic_lock);
- return 0;
-}
-/************************************************************/
-
-/* tsc timer_opts struct */
-static struct timer_opts timer_hpet __read_mostly = {
- .name = "hpet",
- .mark_offset = mark_offset_hpet,
- .get_offset = get_offset_hpet,
- .monotonic_clock = monotonic_clock_hpet,
- .delay = delay_hpet,
- .resume = hpet_resume,
-};
-
-struct init_timer_opts __initdata timer_hpet_init = {
- .init = init_hpet,
- .opts = &timer_hpet,
-};
diff --git a/arch/i386/kernel/timers/timer_none.c b/arch/i386/kernel/timers/timer_none.c
deleted file mode 100644
index 4ea2f41..0000000
--- a/arch/i386/kernel/timers/timer_none.c
+++ /dev/null
@@ -1,39 +0,0 @@
-#include <linux/init.h>
-#include <asm/timer.h>
-
-static void mark_offset_none(void)
-{
- /* nothing needed */
-}
-
-static unsigned long get_offset_none(void)
-{
- return 0;
-}
-
-static unsigned long long monotonic_clock_none(void)
-{
- return 0;
-}
-
-static void delay_none(unsigned long loops)
-{
- int d0;
- __asm__ __volatile__(
- "\tjmp 1f\n"
- ".align 16\n"
- "1:\tjmp 2f\n"
- ".align 16\n"
- "2:\tdecl %0\n\tjns 2b"
- :"=&a" (d0)
- :"0" (loops));
-}
-
-/* none timer_opts struct */
-struct timer_opts timer_none = {
- .name = "none",
- .mark_offset = mark_offset_none,
- .get_offset = get_offset_none,
- .monotonic_clock = monotonic_clock_none,
- .delay = delay_none,
-};
diff --git a/arch/i386/kernel/timers/timer_pit.c b/arch/i386/kernel/timers/timer_pit.c
deleted file mode 100644
index 44cbdf9..0000000
--- a/arch/i386/kernel/timers/timer_pit.c
+++ /dev/null
@@ -1,164 +0,0 @@
-/*
- * This code largely moved from arch/i386/kernel/time.c.
- * See comments there for proper credits.
- */
-
-#include <linux/spinlock.h>
-#include <linux/module.h>
-#include <linux/device.h>
-#include <linux/sysdev.h>
-#include <linux/timex.h>
-#include <asm/delay.h>
-#include <asm/mpspec.h>
-#include <asm/timer.h>
-#include <asm/smp.h>
-#include <asm/io.h>
-#include <asm/arch_hooks.h>
-#include <asm/i8253.h>
-
-#include "do_timer.h"
-#include "io_ports.h"
-
-static int count_p; /* counter in get_offset_pit() */
-
-static int __init init_pit(char* override)
-{
- /* check clock override */
- if (override[0] && strncmp(override,"pit",3))
- printk(KERN_ERR "Warning: clock= override failed. Defaulting "
- "to PIT\n");
- init_cpu_khz();
- count_p = LATCH;
- return 0;
-}
-
-static void mark_offset_pit(void)
-{
- /* nothing needed */
-}
-
-static unsigned long long monotonic_clock_pit(void)
-{
- return 0;
-}
-
-static void delay_pit(unsigned long loops)
-{
- int d0;
- __asm__ __volatile__(
- "\tjmp 1f\n"
- ".align 16\n"
- "1:\tjmp 2f\n"
- ".align 16\n"
- "2:\tdecl %0\n\tjns 2b"
- :"=&a" (d0)
- :"0" (loops));
-}
-
-
-/* This function must be called with xtime_lock held.
- * It was inspired by Steve McCanne's microtime-i386 for BSD. -- jrs
- *
- * However, the pc-audio speaker driver changes the divisor so that
- * it gets interrupted rather more often - it loads 64 into the
- * counter rather than 11932! This has an adverse impact on
- * do_gettimeoffset() -- it stops working! What is also not
- * good is that the interval that our timer function gets called
- * is no longer 10.0002 ms, but 9.9767 ms. To get around this
- * would require using a different timing source. Maybe someone
- * could use the RTC - I know that this can interrupt at frequencies
- * ranging from 8192Hz to 2Hz. If I had the energy, I'd somehow fix
- * it so that at startup, the timer code in sched.c would select
- * using either the RTC or the 8253 timer. The decision would be
- * based on whether there was any other device around that needed
- * to trample on the 8253. I'd set up the RTC to interrupt at 1024 Hz,
- * and then do some jiggery to have a version of do_timer that
- * advanced the clock by 1/1024 s. Every time that reached over 1/100
- * of a second, then do all the old code. If the time was kept correct
- * then do_gettimeoffset could just return 0 - there is no low order
- * divider that can be accessed.
- *
- * Ideally, you would be able to use the RTC for the speaker driver,
- * but it appears that the speaker driver really needs interrupt more
- * often than every 120 us or so.
- *
- * Anyway, this needs more thought.... pjsg (1993-08-28)
- *
- * If you are really that interested, you should be reading
- * comp.protocols.time.ntp!
- */
-
-static unsigned long get_offset_pit(void)
-{
- int count;
- unsigned long flags;
- static unsigned long jiffies_p = 0;
-
- /*
- * cache volatile jiffies temporarily; we have xtime_lock.
- */
- unsigned long jiffies_t;
-
- spin_lock_irqsave(&i8253_lock, flags);
- /* timer count may underflow right here */
- outb_p(0x00, PIT_MODE); /* latch the count ASAP */
-
- count = inb_p(PIT_CH0); /* read the latched count */
-
- /*
- * We do this guaranteed double memory access instead of a _p
- * postfix in the previous port access. Wheee, hackady hack
- */
- jiffies_t = jiffies;
-
- count |= inb_p(PIT_CH0) << 8;
-
- /* VIA686a test code... reset the latch if count > max + 1 */
- if (count > LATCH) {
- outb_p(0x34, PIT_MODE);
- outb_p(LATCH & 0xff, PIT_CH0);
- outb(LATCH >> 8, PIT_CH0);
- count = LATCH - 1;
- }
-
- /*
- * avoiding timer inconsistencies (they are rare, but they happen)...
- * there are two kinds of problems that must be avoided here:
- * 1. the timer counter underflows
- * 2. hardware problem with the timer, not giving us continuous time,
- * the counter does small "jumps" upwards on some Pentium systems,
- * (see c't 95/10 page 335 for Neptun bug.)
- */
-
- if( jiffies_t == jiffies_p ) {
- if( count > count_p ) {
- /* the nutcase */
- count = do_timer_overflow(count);
- }
- } else
- jiffies_p = jiffies_t;
-
- count_p = count;
-
- spin_unlock_irqrestore(&i8253_lock, flags);
-
- count = ((LATCH-1) - count) * TICK_SIZE;
- count = (count + LATCH/2) / LATCH;
-
- return count;
-}
-
-
-/* tsc timer_opts struct */
-struct timer_opts timer_pit = {
- .name = "pit",
- .mark_offset = mark_offset_pit,
- .get_offset = get_offset_pit,
- .monotonic_clock = monotonic_clock_pit,
- .delay = delay_pit,
-};
-
-struct init_timer_opts __initdata timer_pit_init = {
- .init = init_pit,
- .opts = &timer_pit,
-};
diff --git a/arch/i386/kernel/timers/timer_pm.c b/arch/i386/kernel/timers/timer_pm.c
deleted file mode 100644
index 264edaa..0000000
--- a/arch/i386/kernel/timers/timer_pm.c
+++ /dev/null
@@ -1,268 +0,0 @@
-/*
- * (C) Dominik Brodowski <[email protected]> 2003
- *
- * Driver to use the Power Management Timer (PMTMR) available in some
- * southbridges as primary timing source for the Linux kernel.
- *
- * Based on parts of linux/drivers/acpi/hardware/hwtimer.c, timer_pit.c,
- * timer_hpet.c, and on Arjan van de Ven's implementation for 2.4.
- *
- * This file is licensed under the GPL v2.
- */
-
-
-#include <linux/kernel.h>
-#include <linux/module.h>
-#include <linux/device.h>
-#include <linux/init.h>
-#include <asm/types.h>
-#include <asm/timer.h>
-#include <asm/smp.h>
-#include <asm/io.h>
-#include <asm/arch_hooks.h>
-
-#include <linux/timex.h>
-#include "mach_timer.h"
-
-/* Number of PMTMR ticks expected during calibration run */
-#define PMTMR_TICKS_PER_SEC 3579545
-#define PMTMR_EXPECTED_RATE \
- ((CALIBRATE_LATCH * (PMTMR_TICKS_PER_SEC >> 10)) / (CLOCK_TICK_RATE>>10))
-
-
-/* The I/O port the PMTMR resides at.
- * The location is detected during setup_arch(),
- * in arch/i386/acpi/boot.c */
-u32 pmtmr_ioport = 0;
-
-
-/* value of the Power timer at last timer interrupt */
-static u32 offset_tick;
-static u32 offset_delay;
-
-static unsigned long long monotonic_base;
-static seqlock_t monotonic_lock = SEQLOCK_UNLOCKED;
-
-#define ACPI_PM_MASK 0xFFFFFF /* limit it to 24 bits */
-
-/*helper function to safely read acpi pm timesource*/
-static inline u32 read_pmtmr(void)
-{
- u32 v1=0,v2=0,v3=0;
- /* It has been reported that because of various broken
- * chipsets (ICH4, PIIX4 and PIIX4E) where the ACPI PM time
- * source is not latched, so you must read it multiple
- * times to insure a safe value is read.
- */
- do {
- v1 = inl(pmtmr_ioport);
- v2 = inl(pmtmr_ioport);
- v3 = inl(pmtmr_ioport);
- } while ((v1 > v2 && v1 < v3) || (v2 > v3 && v2 < v1)
- || (v3 > v1 && v3 < v2));
-
- /* mask the output to 24 bits */
- return v2 & ACPI_PM_MASK;
-}
-
-
-/*
- * Some boards have the PMTMR running way too fast. We check
- * the PMTMR rate against PIT channel 2 to catch these cases.
- */
-static int verify_pmtmr_rate(void)
-{
- u32 value1, value2;
- unsigned long count, delta;
-
- mach_prepare_counter();
- value1 = read_pmtmr();
- mach_countup(&count);
- value2 = read_pmtmr();
- delta = (value2 - value1) & ACPI_PM_MASK;
-
- /* Check that the PMTMR delta is within 5% of what we expect */
- if (delta < (PMTMR_EXPECTED_RATE * 19) / 20 ||
- delta > (PMTMR_EXPECTED_RATE * 21) / 20) {
- printk(KERN_INFO "PM-Timer running at invalid rate: %lu%% of normal - aborting.\n", 100UL * delta / PMTMR_EXPECTED_RATE);
- return -1;
- }
-
- return 0;
-}
-
-
-static int init_pmtmr(char* override)
-{
- u32 value1, value2;
- unsigned int i;
-
- if (override[0] && strncmp(override,"pmtmr",5))
- return -ENODEV;
-
- if (!pmtmr_ioport)
- return -ENODEV;
-
- /* we use the TSC for delay_pmtmr, so make sure it exists */
- if (!cpu_has_tsc)
- return -ENODEV;
-
- /* "verify" this timing source */
- value1 = read_pmtmr();
- for (i = 0; i < 10000; i++) {
- value2 = read_pmtmr();
- if (value2 == value1)
- continue;
- if (value2 > value1)
- goto pm_good;
- if ((value2 < value1) && ((value2) < 0xFFF))
- goto pm_good;
- printk(KERN_INFO "PM-Timer had inconsistent results: 0x%#x, 0x%#x - aborting.\n", value1, value2);
- return -EINVAL;
- }
- printk(KERN_INFO "PM-Timer had no reasonable result: 0x%#x - aborting.\n", value1);
- return -ENODEV;
-
-pm_good:
- if (verify_pmtmr_rate() != 0)
- return -ENODEV;
-
- init_cpu_khz();
- return 0;
-}
-
-static inline u32 cyc2us(u32 cycles)
-{
- /* The Power Management Timer ticks at 3.579545 ticks per microsecond.
- * 1 / PM_TIMER_FREQUENCY == 0.27936511 =~ 286/1024 [error: 0.024%]
- *
- * Even with HZ = 100, delta is at maximum 35796 ticks, so it can
- * easily be multiplied with 286 (=0x11E) without having to fear
- * u32 overflows.
- */
- cycles *= 286;
- return (cycles >> 10);
-}
-
-/*
- * this gets called during each timer interrupt
- * - Called while holding the writer xtime_lock
- */
-static void mark_offset_pmtmr(void)
-{
- u32 lost, delta, last_offset;
- static int first_run = 1;
- last_offset = offset_tick;
-
- write_seqlock(&monotonic_lock);
-
- offset_tick = read_pmtmr();
-
- /* calculate tick interval */
- delta = (offset_tick - last_offset) & ACPI_PM_MASK;
-
- /* convert to usecs */
- delta = cyc2us(delta);
-
- /* update the monotonic base value */
- monotonic_base += delta * NSEC_PER_USEC;
- write_sequnlock(&monotonic_lock);
-
- /* convert to ticks */
- delta += offset_delay;
- lost = delta / (USEC_PER_SEC / HZ);
- offset_delay = delta % (USEC_PER_SEC / HZ);
-
-
- /* compensate for lost ticks */
- if (lost >= 2)
- jiffies_64 += lost - 1;
-
- /* don't calculate delay for first run,
- or if we've got less then a tick */
- if (first_run || (lost < 1)) {
- first_run = 0;
- offset_delay = 0;
- }
-}
-
-static int pmtmr_resume(void)
-{
- write_seqlock(&monotonic_lock);
- /* Assume this is the last mark offset time */
- offset_tick = read_pmtmr();
- write_sequnlock(&monotonic_lock);
- return 0;
-}
-
-static unsigned long long monotonic_clock_pmtmr(void)
-{
- u32 last_offset, this_offset;
- unsigned long long base, ret;
- unsigned seq;
-
-
- /* atomically read monotonic base & last_offset */
- do {
- seq = read_seqbegin(&monotonic_lock);
- last_offset = offset_tick;
- base = monotonic_base;
- } while (read_seqretry(&monotonic_lock, seq));
-
- /* Read the pmtmr */
- this_offset = read_pmtmr();
-
- /* convert to nanoseconds */
- ret = (this_offset - last_offset) & ACPI_PM_MASK;
- ret = base + (cyc2us(ret) * NSEC_PER_USEC);
- return ret;
-}
-
-static void delay_pmtmr(unsigned long loops)
-{
- unsigned long bclock, now;
-
- rdtscl(bclock);
- do
- {
- rep_nop();
- rdtscl(now);
- } while ((now-bclock) < loops);
-}
-
-
-/*
- * get the offset (in microseconds) from the last call to mark_offset()
- * - Called holding a reader xtime_lock
- */
-static unsigned long get_offset_pmtmr(void)
-{
- u32 now, offset, delta = 0;
-
- offset = offset_tick;
- now = read_pmtmr();
- delta = (now - offset)&ACPI_PM_MASK;
-
- return (unsigned long) offset_delay + cyc2us(delta);
-}
-
-
-/* acpi timer_opts struct */
-static struct timer_opts timer_pmtmr = {
- .name = "pmtmr",
- .mark_offset = mark_offset_pmtmr,
- .get_offset = get_offset_pmtmr,
- .monotonic_clock = monotonic_clock_pmtmr,
- .delay = delay_pmtmr,
- .read_timer = read_timer_tsc,
- .resume = pmtmr_resume,
-};
-
-struct init_timer_opts __initdata timer_pmtmr_init = {
- .init = init_pmtmr,
- .opts = &timer_pmtmr,
-};
-
-MODULE_LICENSE("GPL");
-MODULE_AUTHOR("Dominik Brodowski <[email protected]>");
-MODULE_DESCRIPTION("Power Management Timer (PMTMR) as primary timing source for x86");
diff --git a/arch/i386/kernel/timers/timer_tsc.c b/arch/i386/kernel/timers/timer_tsc.c
deleted file mode 100644
index 243ec04..0000000
--- a/arch/i386/kernel/timers/timer_tsc.c
+++ /dev/null
@@ -1,439 +0,0 @@
-/*
- * This code largely moved from arch/i386/kernel/time.c.
- * See comments there for proper credits.
- *
- * 2004-06-25 Jesper Juhl
- * moved mark_offset_tsc below cpufreq_delayed_get to avoid gcc 3.4
- * failing to inline.
- */
-
-#include <linux/spinlock.h>
-#include <linux/init.h>
-#include <linux/timex.h>
-#include <linux/errno.h>
-#include <linux/cpufreq.h>
-#include <linux/string.h>
-#include <linux/jiffies.h>
-
-#include <asm/timer.h>
-#include <asm/io.h>
-/* processor.h for distable_tsc flag */
-#include <asm/processor.h>
-
-#include "io_ports.h"
-#include "mach_timer.h"
-
-#include <asm/hpet.h>
-#include <asm/i8253.h>
-
-#ifdef CONFIG_HPET_TIMER
-static unsigned long hpet_usec_quotient;
-static unsigned long hpet_last;
-static struct timer_opts timer_tsc;
-#endif
-
-static int use_tsc;
-/* Number of usecs that the last interrupt was delayed */
-static int delay_at_last_interrupt;
-
-static unsigned long last_tsc_low; /* lsb 32 bits of Time Stamp Counter */
-static unsigned long last_tsc_high; /* msb 32 bits of Time Stamp Counter */
-static unsigned long long monotonic_base;
-static seqlock_t monotonic_lock = SEQLOCK_UNLOCKED;
-
-/* Avoid compensating for lost ticks before TSCs are synched */
-static int detect_lost_ticks;
-static int __init start_lost_tick_compensation(void)
-{
- detect_lost_ticks = 1;
- return 0;
-}
-late_initcall(start_lost_tick_compensation);
-
-/* convert from cycles(64bits) => nanoseconds (64bits)
- * basic equation:
- * ns = cycles / (freq / ns_per_sec)
- * ns = cycles * (ns_per_sec / freq)
- * ns = cycles * (10^9 / (cpu_khz * 10^3))
- * ns = cycles * (10^6 / cpu_khz)
- *
- * Then we use scaling math (suggested by [email protected]) to get:
- * ns = cycles * (10^6 * SC / cpu_khz) / SC
- * ns = cycles * cyc2ns_scale / SC
- *
- * And since SC is a constant power of two, we can convert the div
- * into a shift.
- *
- * We can use khz divisor instead of mhz to keep a better percision, since
- * cyc2ns_scale is limited to 10^6 * 2^10, which fits in 32 bits.
- * ([email protected])
- *
- * [email protected] "math is hard, lets go shopping!"
- */
-static unsigned long cyc2ns_scale __read_mostly;
-#define CYC2NS_SCALE_FACTOR 10 /* 2^10, carefully chosen */
-
-static inline void set_cyc2ns_scale(unsigned long cpu_khz)
-{
- cyc2ns_scale = (1000000 << CYC2NS_SCALE_FACTOR)/cpu_khz;
-}
-
-static inline unsigned long long cycles_2_ns(unsigned long long cyc)
-{
- return (cyc * cyc2ns_scale) >> CYC2NS_SCALE_FACTOR;
-}
-
-static int count2; /* counter for mark_offset_tsc() */
-
-/* Cached *multiplier* to convert TSC counts to microseconds.
- * (see the equation below).
- * Equal to 2^32 * (1 / (clocks per usec) ).
- * Initialized in time_init.
- */
-static unsigned long fast_gettimeoffset_quotient;
-
-static unsigned long get_offset_tsc(void)
-{
- register unsigned long eax, edx;
-
- /* Read the Time Stamp Counter */
-
- rdtsc(eax,edx);
-
- /* .. relative to previous jiffy (32 bits is enough) */
- eax -= last_tsc_low; /* tsc_low delta */
-
- /*
- * Time offset = (tsc_low delta) * fast_gettimeoffset_quotient
- * = (tsc_low delta) * (usecs_per_clock)
- * = (tsc_low delta) * (usecs_per_jiffy / clocks_per_jiffy)
- *
- * Using a mull instead of a divl saves up to 31 clock cycles
- * in the critical path.
- */
-
- __asm__("mull %2"
- :"=a" (eax), "=d" (edx)
- :"rm" (fast_gettimeoffset_quotient),
- "0" (eax));
-
- /* our adjusted time offset in microseconds */
- return delay_at_last_interrupt + edx;
-}
-
-static unsigned long long monotonic_clock_tsc(void)
-{
- unsigned long long last_offset, this_offset, base;
- unsigned seq;
-
- /* atomically read monotonic base & last_offset */
- do {
- seq = read_seqbegin(&monotonic_lock);
- last_offset = ((unsigned long long)last_tsc_high<<32)|last_tsc_low;
- base = monotonic_base;
- } while (read_seqretry(&monotonic_lock, seq));
-
- /* Read the Time Stamp Counter */
- rdtscll(this_offset);
-
- /* return the value in ns */
- return base + cycles_2_ns(this_offset - last_offset);
-}
-
-static void delay_tsc(unsigned long loops)
-{
- unsigned long bclock, now;
-
- rdtscl(bclock);
- do
- {
- rep_nop();
- rdtscl(now);
- } while ((now-bclock) < loops);
-}
-
-#ifdef CONFIG_HPET_TIMER
-static void mark_offset_tsc_hpet(void)
-{
- unsigned long long this_offset, last_offset;
- unsigned long offset, temp, hpet_current;
-
- write_seqlock(&monotonic_lock);
- last_offset = ((unsigned long long)last_tsc_high<<32)|last_tsc_low;
- /*
- * It is important that these two operations happen almost at
- * the same time. We do the RDTSC stuff first, since it's
- * faster. To avoid any inconsistencies, we need interrupts
- * disabled locally.
- */
- /*
- * Interrupts are just disabled locally since the timer irq
- * has the SA_INTERRUPT flag set. -arca
- */
- /* read Pentium cycle counter */
-
- hpet_current = hpet_readl(HPET_COUNTER);
- rdtsc(last_tsc_low, last_tsc_high);
-
- /* lost tick compensation */
- offset = hpet_readl(HPET_T0_CMP) - hpet_tick;
- if (unlikely(((offset - hpet_last) > hpet_tick) && (hpet_last != 0))
- && detect_lost_ticks) {
- int lost_ticks = (offset - hpet_last) / hpet_tick;
- jiffies_64 += lost_ticks;
- }
- hpet_last = hpet_current;
-
- /* update the monotonic base value */
- this_offset = ((unsigned long long)last_tsc_high<<32)|last_tsc_low;
- monotonic_base += cycles_2_ns(this_offset - last_offset);
- write_sequnlock(&monotonic_lock);
-
- /* calculate delay_at_last_interrupt */
- /*
- * Time offset = (hpet delta) * ( usecs per HPET clock )
- * = (hpet delta) * ( usecs per tick / HPET clocks per tick)
- * = (hpet delta) * ( hpet_usec_quotient ) / (2^32)
- * Where,
- * hpet_usec_quotient = (2^32 * usecs per tick)/HPET clocks per tick
- */
- delay_at_last_interrupt = hpet_current - offset;
- ASM_MUL64_REG(temp, delay_at_last_interrupt,
- hpet_usec_quotient, delay_at_last_interrupt);
-}
-#endif
-
-static void mark_offset_tsc(void)
-{
- unsigned long lost,delay;
- unsigned long delta = last_tsc_low;
- int count;
- int countmp;
- static int count1 = 0;
- unsigned long long this_offset, last_offset;
- static int lost_count = 0;
-
- write_seqlock(&monotonic_lock);
- last_offset = ((unsigned long long)last_tsc_high<<32)|last_tsc_low;
- /*
- * It is important that these two operations happen almost at
- * the same time. We do the RDTSC stuff first, since it's
- * faster. To avoid any inconsistencies, we need interrupts
- * disabled locally.
- */
-
- /*
- * Interrupts are just disabled locally since the timer irq
- * has the SA_INTERRUPT flag set. -arca
- */
-
- /* read Pentium cycle counter */
-
- rdtsc(last_tsc_low, last_tsc_high);
-
- spin_lock(&i8253_lock);
- outb_p(0x00, PIT_MODE); /* latch the count ASAP */
-
- count = inb_p(PIT_CH0); /* read the latched count */
- count |= inb(PIT_CH0) << 8;
-
- /*
- * VIA686a test code... reset the latch if count > max + 1
- * from timer_pit.c - cjb
- */
- if (count > LATCH) {
- outb_p(0x34, PIT_MODE);
- outb_p(LATCH & 0xff, PIT_CH0);
- outb(LATCH >> 8, PIT_CH0);
- count = LATCH - 1;
- }
-
- spin_unlock(&i8253_lock);
-
- if (pit_latch_buggy) {
- /* get center value of last 3 time lutch */
- if ((count2 >= count && count >= count1)
- || (count1 >= count && count >= count2)) {
- count2 = count1; count1 = count;
- } else if ((count1 >= count2 && count2 >= count)
- || (count >= count2 && count2 >= count1)) {
- countmp = count;count = count2;
- count2 = count1;count1 = countmp;
- } else {
- count2 = count1; count1 = count; count = count1;
- }
- }
-
- /* lost tick compensation */
- delta = last_tsc_low - delta;
- {
- register unsigned long eax, edx;
- eax = delta;
- __asm__("mull %2"
- :"=a" (eax), "=d" (edx)
- :"rm" (fast_gettimeoffset_quotient),
- "0" (eax));
- delta = edx;
- }
- delta += delay_at_last_interrupt;
- lost = delta/(1000000/HZ);
- delay = delta%(1000000/HZ);
- if (lost >= 2 && detect_lost_ticks) {
- jiffies_64 += lost-1;
-
- /* sanity check to ensure we're not always losing ticks */
- if (lost_count++ > 100) {
- printk(KERN_WARNING "Losing too many ticks!\n");
- printk(KERN_WARNING "TSC cannot be used as a timesource. \n");
- printk(KERN_WARNING "Possible reasons for this are:\n");
- printk(KERN_WARNING " You're running with Speedstep,\n");
- printk(KERN_WARNING " You don't have DMA enabled for your hard disk (see hdparm),\n");
- printk(KERN_WARNING " Incorrect TSC synchronization on an SMP system (see dmesg).\n");
- printk(KERN_WARNING "Falling back to a sane timesource now.\n");
-
- clock_fallback();
- }
- } else
- lost_count = 0;
- /* update the monotonic base value */
- this_offset = ((unsigned long long)last_tsc_high<<32)|last_tsc_low;
- monotonic_base += cycles_2_ns(this_offset - last_offset);
- write_sequnlock(&monotonic_lock);
-
- /* calculate delay_at_last_interrupt */
- count = ((LATCH-1) - count) * TICK_SIZE;
- delay_at_last_interrupt = (count + LATCH/2) / LATCH;
-
- /* catch corner case where tick rollover occured
- * between tsc and pit reads (as noted when
- * usec delta is > 90% # of usecs/tick)
- */
- if (lost && abs(delay - delay_at_last_interrupt) > (900000/HZ))
- jiffies_64++;
-}
-
-static int __init init_tsc(char* override)
-{
-
- /* check clock override */
- if (override[0] && strncmp(override,"tsc",3)) {
-#ifdef CONFIG_HPET_TIMER
- if (is_hpet_enabled()) {
- printk(KERN_ERR "Warning: clock= override failed. Defaulting to tsc\n");
- } else
-#endif
- {
- return -ENODEV;
- }
- }
-
- /*
- * If we have APM enabled or the CPU clock speed is variable
- * (CPU stops clock on HLT or slows clock to save power)
- * then the TSC timestamps may diverge by up to 1 jiffy from
- * 'real time' but nothing will break.
- * The most frequent case is that the CPU is "woken" from a halt
- * state by the timer interrupt itself, so we get 0 error. In the
- * rare cases where a driver would "wake" the CPU and request a
- * timestamp, the maximum error is < 1 jiffy. But timestamps are
- * still perfectly ordered.
- * Note that the TSC counter will be reset if APM suspends
- * to disk; this won't break the kernel, though, 'cuz we're
- * smart. See arch/i386/kernel/apm.c.
- */
- /*
- * Firstly we have to do a CPU check for chips with
- * a potentially buggy TSC. At this point we haven't run
- * the ident/bugs checks so we must run this hook as it
- * may turn off the TSC flag.
- *
- * NOTE: this doesn't yet handle SMP 486 machines where only
- * some CPU's have a TSC. Thats never worked and nobody has
- * moaned if you have the only one in the world - you fix it!
- */
-
- count2 = LATCH; /* initialize counter for mark_offset_tsc() */
-
- if (cpu_has_tsc) {
- unsigned long tsc_quotient;
-#ifdef CONFIG_HPET_TIMER
- if (is_hpet_enabled() && hpet_use_timer) {
- unsigned long result, remain;
- printk("Using TSC for gettimeofday\n");
- tsc_quotient = calibrate_tsc_hpet(NULL);
- timer_tsc.mark_offset = &mark_offset_tsc_hpet;
- /*
- * Math to calculate hpet to usec multiplier
- * Look for the comments at get_offset_tsc_hpet()
- */
- ASM_DIV64_REG(result, remain, hpet_tick,
- 0, KERNEL_TICK_USEC);
- if (remain > (hpet_tick >> 1))
- result++; /* rounding the result */
-
- hpet_usec_quotient = result;
- } else
-#endif
- {
- tsc_quotient = calibrate_tsc();
- }
-
- if (tsc_quotient) {
- fast_gettimeoffset_quotient = tsc_quotient;
- use_tsc = 1;
- /*
- * We could be more selective here I suspect
- * and just enable this for the next intel chips ?
- */
- /* report CPU clock rate in Hz.
- * The formula is (10^6 * 2^32) / (2^32 * 1 / (clocks/us)) =
- * clock/second. Our precision is about 100 ppm.
- */
- { unsigned long eax=0, edx=1000;
- __asm__("divl %2"
- :"=a" (cpu_khz), "=d" (edx)
- :"r" (tsc_quotient),
- "0" (eax), "1" (edx));
- printk("Detected %u.%03u MHz processor.\n",
- cpu_khz / 1000, cpu_khz % 1000);
- }
- set_cyc2ns_scale(cpu_khz);
- return 0;
- }
- }
- return -ENODEV;
-}
-
-static int tsc_resume(void)
-{
- write_seqlock(&monotonic_lock);
- /* Assume this is the last mark offset time */
- rdtsc(last_tsc_low, last_tsc_high);
-#ifdef CONFIG_HPET_TIMER
- if (is_hpet_enabled() && hpet_use_timer)
- hpet_last = hpet_readl(HPET_COUNTER);
-#endif
- write_sequnlock(&monotonic_lock);
- return 0;
-}
-
-
-
-
-/************************************************************/
-
-/* tsc timer_opts struct */
-static struct timer_opts timer_tsc = {
- .name = "tsc",
- .mark_offset = mark_offset_tsc,
- .get_offset = get_offset_tsc,
- .monotonic_clock = monotonic_clock_tsc,
- .delay = delay_tsc,
- .read_timer = read_timer_tsc,
- .resume = tsc_resume,
-};
-
-struct init_timer_opts __initdata timer_tsc_init = {
- .init = init_tsc,
- .opts = &timer_tsc,
-};
Change the current_tick_length() function so it takes an
argument which specifies how much precision to return in shifted
nanoseconds. This provides a simple way to convert between NTPs
internal nanoseconds shifted by (SHIFT_SCALE - 10) to other shifted
nanosecond units that are used by the clocksource abstraction.
Signed-off-by John Stultz <[email protected]>
arch/powerpc/kernel/time.c | 2 +-
include/linux/timex.h | 2 +-
kernel/timer.c | 21 +++++++++++++++++----
3 files changed, 19 insertions(+), 6 deletions(-)
linux-2.6.16_timeofday-core2_C1.patch
============================================
diff --git a/arch/powerpc/kernel/time.c b/arch/powerpc/kernel/time.c
index 86f7e3d..08a53a4 100644
--- a/arch/powerpc/kernel/time.c
+++ b/arch/powerpc/kernel/time.c
@@ -315,7 +315,7 @@ static __inline__ void timer_recalc_offs
if (__USE_RTC())
return;
- tlen = current_tick_length();
+ tlen = current_tick_length(SHIFT_SCALE - 10);
offset = cur_tb - do_gtod.varp->tb_orig_stamp;
if (tlen == last_tick_len && offset < 0x80000000u)
return;
diff --git a/include/linux/timex.h b/include/linux/timex.h
index b7ca120..e239f2d 100644
--- a/include/linux/timex.h
+++ b/include/linux/timex.h
@@ -346,7 +346,7 @@ time_interpolator_reset(void)
#endif /* !CONFIG_TIME_INTERPOLATION */
/* Returns how long ticks are at present, in ns / 2^(SHIFT_SCALE-10). */
-extern u64 current_tick_length(void);
+extern u64 current_tick_length(long);
#endif /* KERNEL */
diff --git a/kernel/timer.c b/kernel/timer.c
index 78a9d03..dc9b4ec 100644
--- a/kernel/timer.c
+++ b/kernel/timer.c
@@ -791,16 +791,29 @@ static void update_wall_time_one_tick(vo
* Return how long ticks are at the moment, that is, how much time
* update_wall_time_one_tick will add to xtime next time we call it
* (assuming no calls to do_adjtimex in the meantime).
- * The return value is in fixed-point nanoseconds with SHIFT_SCALE-10
- * bits to the right of the binary point.
+ * The return value is in fixed-point nanoseconds shifted by the
+ * specified number of bits to the right of the binary point.
* This function has no side-effects.
*/
-u64 current_tick_length(void)
+u64 current_tick_length(long shift)
{
long delta_nsec;
+ u64 ret;
+ /* calculate the finest interval NTP will allow.
+ * ie: nanosecond value shifted by (SHIFT_SCALE - 10)
+ */
delta_nsec = tick_nsec + adjtime_adjustment() * 1000;
- return ((u64) delta_nsec << (SHIFT_SCALE - 10)) + time_adj;
+ ret = ((u64) delta_nsec << (SHIFT_SCALE - 10)) + time_adj;
+
+ /* convert from (SHIFT_SCALE - 10) to specified shift scale: */
+ shift = shift - (SHIFT_SCALE - 10);
+ if (shift < 0)
+ ret >>= -shift;
+ else
+ ret <<= shift;
+
+ return ret;
}
/* XXX - all of this timekeeping code should be later moved to time.c */
Instead of incrementing xtime by tick_nsec + ntp adjustments,
use the clocksource abstraction to increment and scale time. Using the
clocksource abstraction allows other clocksources to be used
consistently in the face of late or lost ticks, while preserving the
existing behavior via the jiffies clocksource.
This removes the need to keep time_phase adjustments as we just use the
current_tick_length() function as the NTP interface and accumulate time
using shifted nanoseconds.
The basics of this design was by Roman Zippel, however it is my own
interpretation and implementation, so the credit should go to him and
the blame to me.
Signed-off-by: John Stultz <[email protected]>
include/linux/clocksource.h | 98 ++++++++++++++++++++++++++++++++++++++++++++
kernel/timer.c | 47 ++++++++++++---------
2 files changed, 126 insertions(+), 19 deletions(-)
linux-2.6.16_timeofday-core3_C1.patch
============================================
diff --git a/include/linux/clocksource.h b/include/linux/clocksource.h
index c4187cd..9f1e576 100644
--- a/include/linux/clocksource.h
+++ b/include/linux/clocksource.h
@@ -173,6 +173,104 @@ static inline void calculate_clocksource
c->interval_snsecs = (u64)c->interval_cycles * c->mult;
}
+
+/**
+ * error_aproximation - calculates an error adjustment for a given error
+ *
+ * @error: Error value (unsigned)
+ * @unit: Adjustment unit
+ *
+ * For a given error value, this function takes the adjustment unit
+ * and uses binary approximation to return a power of two adjustment value.
+ *
+ * This function is only for use by the the make_ntp_adj() function
+ * and you must hold a write on the xtime_lock when calling.
+ */
+static inline int error_aproximation(u64 error, u64 unit)
+{
+ static int saved_adj = 0;
+ u64 adjusted_unit = unit << saved_adj;
+
+ if (error > (adjusted_unit * 2)) {
+ /* large error, so increment the adjustment factor */
+ saved_adj++;
+ } else if (error > adjusted_unit) {
+ /* just right, don't touch it */
+ } else if (saved_adj) {
+ /* small error, so drop the adjustment factor */
+ saved_adj--;
+ return 0;
+ }
+
+ return saved_adj;
+}
+
+
+/**
+ * make_ntp_adj - Adjusts the specified clocksource for a given error
+ *
+ * @clock: Pointer to clock to be adjusted
+ * @cycles_delta: Current unacounted cycle delta
+ * @error: Pointer to current error value
+ *
+ * Returns clock shifted nanosecond adjustment to be applied against
+ * the accumulated time value (ie: xtime).
+ *
+ * If the error value is large enough, this function calulates the
+ * (power of two) adjustment value, and adjusts the clock's mult and
+ * interval_snsecs values accordingly.
+ *
+ * However, since there may be some unaccumulated cycles, to avoid
+ * time inconsistencies we must adjust the accumulation value
+ * accordingly.
+ *
+ * This is not very intuitive, so the following proof should help:
+ * The basic timeofday algorithm: base + cycle * mult
+ * Thus:
+ * new_base + cycle * new_mult = old_base + cycle * old_mult
+ * new_base = old_base + cycle * old_mult - cycle * new_mult
+ * new_base = old_base + cycle * (old_mult - new_mult)
+ * new_base - old_base = cycle * (old_mult - new_mult)
+ * base_delta = cycle * (old_mult - new_mult)
+ * base_delta = cycle * (mult_delta)
+ *
+ * Where mult_delta is the adjustment value made to mult
+ *
+ * XXX - Hopefully gcc is smart enough to avoid the multiplies.
+ */
+static inline s64 make_ntp_adj(struct clocksource *clock,
+ cycles_t cycles_delta, s64* error)
+{
+ s64 ret = 0;
+ if (*error > ((s64)clock->interval_cycles+1)/2) {
+ /* calculate adjustment value */
+ int adjustment = 1 << error_aproximation(*error,
+ clock->interval_cycles);
+ /* adjust clock */
+ clock->mult += adjustment;
+ clock->interval_snsecs += clock->interval_cycles * adjustment;
+
+ /* adjust the base and error for the adjustment */
+ ret = -(cycles_delta * adjustment);
+ *error -= clock->interval_cycles * adjustment;
+ /* XXX adj error for cycle_delta offset? */
+ } else if ((-(*error)) > ((s64)clock->interval_cycles+1)/2) {
+ /* calculate adjustment value */
+ int adjustment = 1 << error_aproximation(-(*error),
+ clock->interval_cycles);
+ /* adjust clock */
+ clock->mult -= adjustment;
+ clock->interval_snsecs -= clock->interval_cycles * adjustment;
+
+ /* adjust the base and error for the adjustment */
+ ret = cycles_delta * adjustment;
+ *error += clock->interval_cycles * adjustment;
+ /* XXX adj error for cycle_delta offset? */
+ }
+ return ret;
+}
+
+
/* used to install a new clocksource */
int register_clocksource(struct clocksource*);
void reselect_clocksource(void);
diff --git a/kernel/timer.c b/kernel/timer.c
index dc9b4ec..339d52f 100644
--- a/kernel/timer.c
+++ b/kernel/timer.c
@@ -599,7 +599,6 @@ long time_tolerance = MAXFREQ; /* frequ
long time_precision = 1; /* clock precision (us) */
long time_maxerror = NTP_PHASE_LIMIT; /* maximum error (us) */
long time_esterror = NTP_PHASE_LIMIT; /* estimated error (us) */
-static long time_phase; /* phase offset (scaled us) */
long time_freq = (((NSEC_PER_SEC + HZ/2) % HZ - HZ/2) << SHIFT_USEC) / NSEC_PER_USEC;
/* frequency offset (scaled ppm)*/
static long time_adj; /* tick adjust (scaled 1 / HZ) */
@@ -758,27 +757,14 @@ static long adjtime_adjustment(void)
}
/* in the NTP reference this is called "hardclock()" */
-static void update_wall_time_one_tick(void)
+static void update_ntp_one_tick(void)
{
- long time_adjust_step, delta_nsec;
+ long time_adjust_step;
time_adjust_step = adjtime_adjustment();
if (time_adjust_step)
/* Reduce by this step the amount of time left */
time_adjust -= time_adjust_step;
- delta_nsec = tick_nsec + time_adjust_step * 1000;
- /*
- * Advance the phase, once it gets to one microsecond, then
- * advance the tick more.
- */
- time_phase += time_adj;
- if ((time_phase >= FINENSEC) || (time_phase <= -FINENSEC)) {
- long ltemp = shift_right(time_phase, (SHIFT_SCALE - 10));
- time_phase -= ltemp << (SHIFT_SCALE - 10);
- delta_nsec += ltemp;
- }
- xtime.tv_nsec += delta_nsec;
- time_interpolator_update(delta_nsec);
/* Changes by adjtime() do not take effect till next tick. */
if (time_next_adjust != 0) {
@@ -883,8 +869,13 @@ device_initcall(timekeeping_init_device)
*/
static void update_wall_time(void)
{
+ static s64 remainder_snsecs, error;
+ s64 snsecs_per_sec;
cycle_t now, offset;
+ snsecs_per_sec = (s64)NSEC_PER_SEC << clock->shift;
+ remainder_snsecs += (s64)xtime.tv_nsec << clock->shift;
+
now = read_clocksource(clock);
offset = (now - last_clock_cycle)&clock->mask;
@@ -892,17 +883,35 @@ static void update_wall_time(void)
* case of lost or late ticks, it will accumulate correctly.
*/
while (offset > clock->interval_cycles) {
+ /* get the ntp interval in clock shifted nanoseconds */
+ s64 ntp_snsecs = current_tick_length(clock->shift);
+
/* accumulate one interval */
+ remainder_snsecs += clock->interval_snsecs;
last_clock_cycle += clock->interval_cycles;
offset -= clock->interval_cycles;
- update_wall_time_one_tick();
- if (xtime.tv_nsec >= 1000000000) {
- xtime.tv_nsec -= 1000000000;
+ /* interpolator bits */
+ time_interpolator_update(clock->interval_snsecs
+ >> clock->shift);
+ /* increment the NTP state machine */
+ update_ntp_one_tick();
+
+ /* accumulate error between NTP and clock interval */
+ error += (ntp_snsecs - (s64)clock->interval_snsecs);
+
+ /* correct the clock when NTP error is too big */
+ remainder_snsecs += make_ntp_adj(clock, offset, &error);
+
+ if (remainder_snsecs >= snsecs_per_sec) {
+ remainder_snsecs -= snsecs_per_sec;
xtime.tv_sec++;
second_overflow();
}
}
+ /* store full nanoseconds into xtime */
+ xtime.tv_nsec = remainder_snsecs >> clock->shift;
+ remainder_snsecs -= (s64)xtime.tv_nsec << clock->shift;
}
/*
This introduces the clocksource management infrastructure. A
clocksource is a driver-like architecture generic abstraction of a
free-running counter. This code defines the clocksource structure, and
provides management code for registering, selecting, accessing and
scaling clocksources.
Additionally, this includes the trivial jiffies clocksource, a lowest
common denominator clocksource, provided mainly for use as an example.
Signed-off-by: John Stultz <[email protected]>
Signed-off-by: Ingo Molnar <[email protected]>
Signed-off-by: Paul Mundt <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>
Signed-off-by: John Stultz <[email protected]>
Documentation/kernel-parameters.txt | 14 +
include/linux/clocksource.h | 181 ++++++++++++++++++
kernel/time/Makefile | 1
kernel/time/clocksource.c | 343 ++++++++++++++++++++++++++++++++++++
kernel/time/jiffies.c | 73 +++++++
5 files changed, 608 insertions(+), 4 deletions(-)
linux-2.6.16_timeofday-clocksource-core_C1.patch
============================================
diff --git a/Documentation/kernel-parameters.txt b/Documentation/kernel-parameters.txt
index fc99075..bf5b337 100644
--- a/Documentation/kernel-parameters.txt
+++ b/Documentation/kernel-parameters.txt
@@ -52,6 +52,7 @@ restrictions referred to are that the re
MTD MTD support is enabled.
NET Appropriate network support is enabled.
NUMA NUMA support is enabled.
+ GENERIC_TIME The generic timeofday code is enabled.
NFS Appropriate NFS support is enabled.
OSS OSS sound support is enabled.
PARIDE The ParIDE subsystem is enabled.
@@ -329,10 +330,11 @@ running once the system is up.
Value can be changed at runtime via
/selinux/checkreqprot.
- clock= [BUGS=IA-32,HW] gettimeofday timesource override.
- Forces specified timesource (if avaliable) to be used
- when calculating gettimeofday(). If specicified
- timesource is not avalible, it defaults to PIT.
+ clock= [BUGS=IA-32, HW] gettimeofday clocksource override.
+ [Deprecated]
+ Forces specified clocksource (if avaliable) to be used
+ when calculating gettimeofday(). If specified
+ clocksource is not avalible, it defaults to PIT.
Format: { pit | tsc | cyclone | pmtmr }
disable_8254_timer
@@ -1579,6 +1581,10 @@ running once the system is up.
time Show timing data prefixed to each printk message line
+ clocksource= [GENERIC_TIME] Override the default clocksource
+ Override the default clocksource and use the clocksource
+ with the name specified.
+
tipar.timeout= [HW,PPT]
Set communications timeout in tenths of a second
(default 15).
diff --git a/include/linux/clocksource.h b/include/linux/clocksource.h
new file mode 100644
index 0000000..c4187cd
--- /dev/null
+++ b/include/linux/clocksource.h
@@ -0,0 +1,181 @@
+/* linux/include/linux/clocksource.h
+ *
+ * This file contains the structure definitions for clocksources.
+ *
+ * If you are not a clocksource, or timekeeping code, you should
+ * not be including this file!
+ */
+#ifndef _LINUX_CLOCKSOURCE_H
+#define _LINUX_CLOCKSOURCE_H
+
+#include <linux/types.h>
+#include <linux/timex.h>
+#include <linux/time.h>
+#include <linux/list.h>
+#include <asm/div64.h>
+#include <asm/io.h>
+
+/* clocksource cycle base type */
+typedef u64 cycle_t;
+
+/**
+ * struct clocksource - hardware abstraction for a free running counter
+ * Provides mostly state-free accessors to the underlying hardware.
+ *
+ * @name: ptr to clocksource name
+ * @list: list head for registration
+ * @rating: rating value for selection (higher is better)
+ * To avoid rating inflation the following
+ * list should give you a guide as to how
+ * to assign your clocksource a rating
+ * 1-99: Unfit for real use
+ * Only available for bootup and testing purposes.
+ * 100-199: Base level usability.
+ * Functional for real use, but not desired.
+ * 200-299: Good.
+ * A correct and usable clocksource.
+ * 300-399: Desired.
+ * A reasonably fast and accurate clocksource.
+ * 400-499: Perfect
+ * The ideal clocksource. A must-use where
+ * available.
+ * @read: returns a cycle value
+ * @mask: bitmask for two's complement
+ * subtraction of non 64 bit counters
+ * @mult: cycle to nanosecond multiplier
+ * @shift: cycle to nanosecond divisor (power of two)
+ * @update_callback: called when safe to alter clocksource values
+ * @is_continuous: defines if clocksource is free-running.
+ * @interval_cycles: Used internally by timekeeping core, please ignore.
+ * @interval_snsecs: Used internally by timekeeping core, please ignore.
+ */
+struct clocksource {
+ char *name;
+ struct list_head list;
+ int rating;
+ cycle_t (*read)(void);
+ cycle_t mask;
+ u32 mult;
+ u32 shift;
+ int (*update_callback)(void);
+ int is_continuous;
+
+ /* timekeeping specific data, ignore */
+ cycle_t interval_cycles;
+ u64 interval_snsecs;
+};
+
+
+/**
+ * clocksource_khz2mult - calculates mult from khz and shift
+ * @khz: Clocksource frequency in KHz
+ * @shift_constant: Clocksource shift factor
+ *
+ * Helper functions that converts a khz counter frequency to a timsource
+ * multiplier, given the clocksource shift value
+ */
+static inline u32 clocksource_khz2mult(u32 khz, u32 shift_constant)
+{
+ /* khz = cyc/(Million ns)
+ * mult/2^shift = ns/cyc
+ * mult = ns/cyc * 2^shift
+ * mult = 1Million/khz * 2^shift
+ * mult = 1000000 * 2^shift / khz
+ * mult = (1000000<<shift) / khz
+ */
+ u64 tmp = ((u64)1000000) << shift_constant;
+
+ tmp += khz/2; /* round for do_div */
+ do_div(tmp, khz);
+
+ return (u32)tmp;
+}
+
+/**
+ * clocksource_hz2mult - calculates mult from hz and shift
+ * @hz: Clocksource frequency in Hz
+ * @shift_constant: Clocksource shift factor
+ *
+ * Helper functions that converts a hz counter
+ * frequency to a timsource multiplier, given the
+ * clocksource shift value
+ */
+static inline u32 clocksource_hz2mult(u32 hz, u32 shift_constant)
+{
+ /* hz = cyc/(Billion ns)
+ * mult/2^shift = ns/cyc
+ * mult = ns/cyc * 2^shift
+ * mult = 1Billion/hz * 2^shift
+ * mult = 1000000000 * 2^shift / hz
+ * mult = (1000000000<<shift) / hz
+ */
+ u64 tmp = ((u64)1000000000) << shift_constant;
+
+ tmp += hz/2; /* round for do_div */
+ do_div(tmp, hz);
+
+ return (u32)tmp;
+}
+
+/**
+ * read_clocksource: - Access the clocksource's current cycle value
+ * @cs: pointer to clocksource being read
+ *
+ * Uses the clocksource to return the current cycle_t value
+ */
+static inline cycle_t read_clocksource(struct clocksource *cs)
+{
+ return cs->read();
+}
+
+/**
+ * cyc2ns - converts clocksource cycles to nanoseconds
+ * @cs: Pointer to clocksource
+ * @cycles: Cycles
+ *
+ * Uses the clocksource and ntp ajdustment to convert cycle_ts to nanoseconds.
+ *
+ * XXX - This could use some mult_lxl_ll() asm optimization
+ */
+static inline s64 cyc2ns(struct clocksource *cs, cycle_t cycles)
+{
+ u64 ret = (u64)cycles;
+ ret = (ret * cs->mult) >> cs->shift;
+ return ret;
+}
+
+/**
+ * calculate_clocksource_interval - Calculates a clocksource interval struct
+ *
+ * @c: Pointer to clocksource.
+ * @length_nsec: Desired interval length in nanoseconds.
+ *
+ * Calculates a fixed cycle/nsec interval for a given clocksource/adjustment
+ * pair and interval request.
+ *
+ * Unless you're the timekeeping code, you should not be using this!
+ */
+static inline void calculate_clocksource_interval(struct clocksource *c,
+ unsigned long length_nsec)
+{
+ u64 tmp;
+
+ /* XXX - All of this could use a whole lot of optimization */
+ tmp = length_nsec;
+ tmp <<= c->shift;
+ tmp += c->mult/2;
+ do_div(tmp, c->mult);
+
+ c->interval_cycles = (cycle_t)tmp;
+ if(c->interval_cycles == 0)
+ c->interval_cycles = 1;
+
+ c->interval_snsecs = (u64)c->interval_cycles * c->mult;
+}
+
+/* used to install a new clocksource */
+int register_clocksource(struct clocksource*);
+void reselect_clocksource(void);
+struct clocksource* get_next_clocksource(void);
+
+#endif /* _LINUX_CLOCKSOURCE_H */
diff --git a/kernel/time/Makefile b/kernel/time/Makefile
new file mode 100644
index 0000000..e1dfd8e
--- /dev/null
+++ b/kernel/time/Makefile
@@ -0,0 +1 @@
+obj-y += clocksource.o jiffies.o
diff --git a/kernel/time/clocksource.c b/kernel/time/clocksource.c
new file mode 100644
index 0000000..954a61f
--- /dev/null
+++ b/kernel/time/clocksource.c
@@ -0,0 +1,343 @@
+/*
+ * linux/kernel/time/clocksource.c
+ *
+ * This file contains the functions which manage clocksource drivers.
+ *
+ * Copyright (C) 2004, 2005 IBM, John Stultz ([email protected])
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
+ *
+ * TODO WishList:
+ * o Allow clocksource drivers to be unregistered
+ * o get rid of clocksource_jiffies extern
+ */
+
+#include <linux/clocksource.h>
+#include <linux/sysdev.h>
+#include <linux/init.h>
+#include <linux/module.h>
+
+/* XXX - Would like a better way for initializing curr_clocksource */
+extern struct clocksource clocksource_jiffies;
+
+/*[Clocksource internal variables]---------
+ * curr_clocksource:
+ * currently selected clocksource. Initialized to clocksource_jiffies.
+ * next_clocksource:
+ * pending next selected clocksource.
+ * clocksource_list:
+ * linked list with the registered clocksources
+ * clocksource_lock:
+ * protects manipulations to curr_clocksource and next_clocksource
+ * and the clocksource_list
+ * override_name:
+ * Name of the user-specified clocksource.
+ */
+static struct clocksource *curr_clocksource = &clocksource_jiffies;
+static struct clocksource *next_clocksource;
+static LIST_HEAD(clocksource_list);
+static DEFINE_SPINLOCK(clocksource_lock);
+static char override_name[32];
+static int finished_booting;
+
+/* clocksource_done_booting - Called near the end of bootup
+ *
+ * Hack to avoid lots of clocksource churn at boot time
+ */
+static int clocksource_done_booting(void)
+{
+ finished_booting = 1;
+ return 0;
+}
+
+late_initcall(clocksource_done_booting);
+
+/**
+ * get_next_clocksource - Returns the selected clocksource
+ *
+ */
+struct clocksource *get_next_clocksource(void)
+{
+ unsigned long flags;
+
+ spin_lock_irqsave(&clocksource_lock, flags);
+ if (next_clocksource && finished_booting) {
+ curr_clocksource = next_clocksource;
+ next_clocksource = NULL;
+ }
+ spin_unlock_irqrestore(&clocksource_lock, flags);
+
+ return curr_clocksource;
+}
+
+/**
+ * select_clocksource - Finds the best registered clocksource.
+ *
+ * Private function. Must hold clocksource_lock when called.
+ *
+ * Looks through the list of registered clocksources, returning
+ * the one with the highest rating value. If there is a clocksource
+ * name that matches the override string, it returns that clocksource.
+ */
+static struct clocksource *select_clocksource(void)
+{
+ struct clocksource *best = NULL;
+ struct list_head *tmp;
+
+ list_for_each(tmp, &clocksource_list) {
+ struct clocksource *src;
+
+ src = list_entry(tmp, struct clocksource, list);
+ if (!best)
+ best = src;
+
+ /* check for override: */
+ if (strlen(src->name) == strlen(override_name) &&
+ !strcmp(src->name, override_name)) {
+ best = src;
+ break;
+ }
+ /* pick the highest rating: */
+ if (src->rating > best->rating)
+ best = src;
+ }
+
+ return best;
+}
+
+/**
+ * is_registered_source - Checks if clocksource is registered
+ * @c: pointer to a clocksource
+ *
+ * Private helper function. Must hold clocksource_lock when called.
+ *
+ * Returns one if the clocksource is already registered, zero otherwise.
+ */
+static int is_registered_source(struct clocksource *c)
+{
+ int len = strlen(c->name);
+ struct list_head *tmp;
+
+ list_for_each(tmp, &clocksource_list) {
+ struct clocksource *src;
+
+ src = list_entry(tmp, struct clocksource, list);
+ if (strlen(src->name) == len && !strcmp(src->name, c->name))
+ return 1;
+ }
+
+ return 0;
+}
+
+/**
+ * register_clocksource - Used to install new clocksources
+ * @t: clocksource to be registered
+ *
+ * Returns -EBUSY if registration fails, zero otherwise.
+ */
+int register_clocksource(struct clocksource *c)
+{
+ int ret = 0;
+ unsigned long flags;
+
+ spin_lock_irqsave(&clocksource_lock, flags);
+ /* check if clocksource is already registered */
+ if (is_registered_source(c)) {
+ printk("register_clocksource: Cannot register %s. "
+ "Already registered!", c->name);
+ ret = -EBUSY;
+ } else {
+ /* register it */
+ list_add(&c->list, &clocksource_list);
+ /* scan the registered clocksources, and pick the best one */
+ next_clocksource = select_clocksource();
+ }
+ spin_unlock_irqrestore(&clocksource_lock, flags);
+ return ret;
+}
+
+EXPORT_SYMBOL(register_clocksource);
+
+/**
+ * reselect_clocksource - Rescan list for next clocksource
+ *
+ * A quick helper function to be used if a clocksource changes its
+ * rating. Forces the clocksource list to be re-scaned for the best
+ * clocksource.
+ */
+void reselect_clocksource(void)
+{
+ unsigned long flags;
+
+ spin_lock_irqsave(&clocksource_lock, flags);
+ next_clocksource = select_clocksource();
+ spin_unlock_irqrestore(&clocksource_lock, flags);
+}
+
+/**
+ * sysfs_show_current_clocksources - sysfs interface for current clocksource
+ * @dev: unused
+ * @buf: char buffer to be filled with clocksource list
+ *
+ * Provides sysfs interface for listing current clocksource.
+ */
+static ssize_t
+sysfs_show_current_clocksources(struct sys_device *dev, char *buf)
+{
+ char *curr = buf;
+
+ spin_lock_irq(&clocksource_lock);
+ curr += sprintf(curr, "%s ", curr_clocksource->name);
+ spin_unlock_irq(&clocksource_lock);
+
+ curr += sprintf(curr, "\n");
+
+ return curr - buf;
+}
+
+/**
+ * sysfs_override_clocksource - interface for manually overriding clocksource
+ * @dev: unused
+ * @buf: name of override clocksource
+ * @count: length of buffer
+ *
+ * Takes input from sysfs interface for manually overriding the default
+ * clocksource selction.
+ */
+static ssize_t sysfs_override_clocksource(struct sys_device *dev,
+ const char *buf, size_t count)
+{
+ size_t ret = count;
+ /* strings from sysfs write are not 0 terminated! */
+ if (count >= sizeof(override_name))
+ return -EINVAL;
+
+ /* strip of \n: */
+ if (buf[count-1] == '\n')
+ count--;
+ if (count < 1)
+ return -EINVAL;
+
+ spin_lock_irq(&clocksource_lock);
+
+ /* copy the name given: */
+ memcpy(override_name, buf, count);
+ override_name[count] = 0;
+
+ /* try to select it: */
+ next_clocksource = select_clocksource();
+
+ spin_unlock_irq(&clocksource_lock);
+
+ return ret;
+}
+
+/**
+ * sysfs_show_available_clocksources - sysfs interface for listing clocksource
+ * @dev: unused
+ * @buf: char buffer to be filled with clocksource list
+ *
+ * Provides sysfs interface for listing registered clocksources
+ */
+static ssize_t
+sysfs_show_available_clocksources(struct sys_device *dev, char *buf)
+{
+ struct list_head *tmp;
+ char *curr = buf;
+
+ spin_lock_irq(&clocksource_lock);
+ list_for_each(tmp, &clocksource_list) {
+ struct clocksource *src;
+
+ src = list_entry(tmp, struct clocksource, list);
+ curr += sprintf(curr, "%s ", src->name);
+ }
+ spin_unlock_irq(&clocksource_lock);
+
+ curr += sprintf(curr, "\n");
+
+ return curr - buf;
+}
+
+/*
+ * Sysfs setup bits:
+ */
+static SYSDEV_ATTR(current_clocksource, 0600, sysfs_show_current_clocksources,
+ sysfs_override_clocksource);
+
+static SYSDEV_ATTR(available_clocksource, 0600,
+ sysfs_show_available_clocksources, NULL);
+
+static struct sysdev_class clocksource_sysclass = {
+ set_kset_name("clocksource"),
+};
+
+static struct sys_device device_clocksource = {
+ .id = 0,
+ .cls = &clocksource_sysclass,
+};
+
+static int init_clocksource_sysfs(void)
+{
+ int error = sysdev_class_register(&clocksource_sysclass);
+
+ if (!error)
+ error = sysdev_register(&device_clocksource);
+ if (!error)
+ error = sysdev_create_file(
+ &device_clocksource,
+ &attr_current_clocksource);
+ if (!error)
+ error = sysdev_create_file(
+ &device_clocksource,
+ &attr_available_clocksource);
+ return error;
+}
+
+device_initcall(init_clocksource_sysfs);
+
+/**
+ * boot_override_clocksource - boot clock override
+ * @str: override name
+ *
+ * Takes a clocksource= boot argument and uses it
+ * as the clocksource override name.
+ */
+static int __init boot_override_clocksource(char* str)
+{
+ spin_lock_irq(&clocksource_lock);
+ if (str)
+ strlcpy(override_name, str, sizeof(override_name));
+ spin_unlock_irq(&clocksource_lock);
+ return 1;
+}
+
+__setup("clocksource=", boot_override_clocksource);
+
+/**
+ * boot_override_clock - Compatibility layer for deprecated boot option
+ * @str: override name
+ *
+ * DEPRECATED! Takes a clock= boot argument and uses it
+ * as the clocksource override name
+ */
+static int __init boot_override_clock(char* str)
+{
+ printk("Warning! clock= boot option is deprecated.\n");
+
+ return boot_override_clocksource(str);
+}
+
+__setup("clock=", boot_override_clock);
diff --git a/kernel/time/jiffies.c b/kernel/time/jiffies.c
new file mode 100644
index 0000000..1fe8376
--- /dev/null
+++ b/kernel/time/jiffies.c
@@ -0,0 +1,73 @@
+/***********************************************************************
+* linux/kernel/time/jiffies.c
+*
+* This file contains the jiffies based clocksource.
+*
+* Copyright (C) 2004, 2005 IBM, John Stultz ([email protected])
+*
+* This program is free software; you can redistribute it and/or modify
+* it under the terms of the GNU General Public License as published by
+* the Free Software Foundation; either version 2 of the License, or
+* (at your option) any later version.
+*
+* This program is distributed in the hope that it will be useful,
+* but WITHOUT ANY WARRANTY; without even the implied warranty of
+* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+* GNU General Public License for more details.
+*
+* You should have received a copy of the GNU General Public License
+* along with this program; if not, write to the Free Software
+* Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
+*
+************************************************************************/
+#include <linux/clocksource.h>
+#include <linux/jiffies.h>
+#include <linux/init.h>
+
+/* The Jiffies based clocksource is the lowest common
+ * denominator clock source which should function on
+ * all systems. It has the same coarse resolution as
+ * the timer interrupt frequency HZ and it suffers
+ * inaccuracies caused by missed or lost timer
+ * interrupts and the inability for the timer
+ * interrupt hardware to accuratly tick at the
+ * requested HZ value. It is also not reccomended
+ * for "tick-less" systems.
+ */
+#define NSEC_PER_JIFFY ((u32)((((u64)NSEC_PER_SEC)<<8)/ACTHZ))
+
+/* Since jiffies uses a simple NSEC_PER_JIFFY multiplier
+ * conversion, the .shift value could be zero. However
+ * this would make NTP adjustments impossible as they are
+ * in units of 1/2^.shift. Thus we use JIFFIES_SHIFT to
+ * shift both the nominator and denominator the same
+ * amount, and give ntp adjustments in units of 1/2^8
+ *
+ * The value 8 is somewhat carefully chosen, as anything
+ * larger can result in overflows. NSEC_PER_JIFFY grows as
+ * HZ shrinks, so values greater then 8 overflow 32bits when
+ * HZ=100.
+ */
+#define JIFFIES_SHIFT 8
+
+static cycle_t jiffies_read(void)
+{
+ return (cycle_t) jiffies;
+}
+
+struct clocksource clocksource_jiffies = {
+ .name = "jiffies",
+ .rating = 0, /* lowest rating*/
+ .read = jiffies_read,
+ .mask = 0xffffffff, /*32bits*/
+ .mult = NSEC_PER_JIFFY << JIFFIES_SHIFT, /* details above */
+ .shift = JIFFIES_SHIFT,
+ .is_continuous = 0, /* tick based, not free running */
+};
+
+static int __init init_jiffies_clocksource(void)
+{
+ return register_clocksource(&clocksource_jiffies);
+}
+
+module_init(init_jiffies_clocksource);
Hi,
On Wed, 22 Mar 2006, john stultz wrote:
> Andrew, All,
> Here is an updated version of the smaller, reworked and
> improved patchset I mailed out monday. Please consider for inclusion
> into your tree.
It looks pretty good already. :)
Give me a bit of time to rework the middle part a bit and if we can agree
to make the new gettimeofday functions optional for an arch, IMO it would
be ok for 2.6.17. I think the important part is to get the generic clock
infrastructure merged, so it can be used by other kernel parts, the
unification of performance sensitive parts can still be done on top of it
a bit later.
One general comment: Currently clock relevant source is scattered in
kernel/time/, drivers/clocksource and arch/... IMO it would be better to
keep at least the first two parts a bit closer, although I'm not sure how
to organize it better. I don't know if we can be so bold to add a toplevel
time/ (similiar to sound/) or maybe we organize a bit like drivers/ide/.
Anyway, maybe someone has a good idea to keep everything a bit closer
together.
bye, Roman
On Thu, 2006-03-23 at 13:48 +0100, Roman Zippel wrote:
> One general comment: Currently clock relevant source is scattered in
> kernel/time/, drivers/clocksource and arch/... IMO it would be better to
> keep at least the first two parts a bit closer, although I'm not sure how
> to organize it better. I don't know if we can be so bold to add a toplevel
> time/ (similiar to sound/) or maybe we organize a bit like drivers/ide/.
> Anyway, maybe someone has a good idea to keep everything a bit closer
> together.
IMO it makes completely sense to move the time/timer/clocks related
generic code into kernel/time.
drivers/clocksource holds drivers which can be shared between
architectures.
The other drivers really should stay in the architecture specific files
as they are often deeply embedded in the SoC or chipset support code.
tglx
Hi,
On Thu, 23 Mar 2006, Thomas Gleixner wrote:
> IMO it makes completely sense to move the time/timer/clocks related
> generic code into kernel/time.
Why? Currently it has two files: jiffies.c is a simple clocksource driver
and clocksource.c is the driver support code.
It's basically driver code, which only is used by some core kernel parts.
bye, Roman
On Thu, 2006-03-23 at 13:48 +0100, Roman Zippel wrote:
> Hi,
>
> On Wed, 22 Mar 2006, john stultz wrote:
>
> > Andrew, All,
> > Here is an updated version of the smaller, reworked and
> > improved patchset I mailed out monday. Please consider for inclusion
> > into your tree.
>
> It looks pretty good already. :)
</me rubs his eyes and reads that again>
> Give me a bit of time to rework the middle part a bit and if we can agree
> to make the new gettimeofday functions optional for an arch, IMO it would
> be ok for 2.6.17.
? The new gettimeofday functions are optional. Don't enable
CONFIG_GENERIC_TIME and you're good to go. Could you clarify what you
mean?
> I think the important part is to get the generic clock
> infrastructure merged, so it can be used by other kernel parts, the
> unification of performance sensitive parts can still be done on top of it
> a bit later.
Ok, I'm still not sure how you intend to you the clocksource bits
outside of timekeeping, but I'm interested in hearing about it.
thanks
-john