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-rw-r--r--arch/powerpc/kernel/time.c282
1 files changed, 99 insertions, 183 deletions
diff --git a/arch/powerpc/kernel/time.c b/arch/powerpc/kernel/time.c
index 1886045a2fd8f8..2a7ddc5793797e 100644
--- a/arch/powerpc/kernel/time.c
+++ b/arch/powerpc/kernel/time.c
@@ -50,6 +50,7 @@
#include <linux/security.h>
#include <linux/percpu.h>
#include <linux/rtc.h>
+#include <linux/jiffies.h>
#include <asm/io.h>
#include <asm/processor.h>
@@ -99,7 +100,15 @@ EXPORT_SYMBOL(tb_ticks_per_usec);
unsigned long tb_ticks_per_sec;
u64 tb_to_xs;
unsigned tb_to_us;
-unsigned long processor_freq;
+
+#define TICKLEN_SCALE (SHIFT_SCALE - 10)
+u64 last_tick_len; /* units are ns / 2^TICKLEN_SCALE */
+u64 ticklen_to_xs; /* 0.64 fraction */
+
+/* If last_tick_len corresponds to about 1/HZ seconds, then
+ last_tick_len << TICKLEN_SHIFT will be about 2^63. */
+#define TICKLEN_SHIFT (63 - 30 - TICKLEN_SCALE + SHIFT_HZ)
+
DEFINE_SPINLOCK(rtc_lock);
EXPORT_SYMBOL_GPL(rtc_lock);
@@ -113,10 +122,6 @@ extern unsigned long wall_jiffies;
extern struct timezone sys_tz;
static long timezone_offset;
-void ppc_adjtimex(void);
-
-static unsigned adjusting_time = 0;
-
unsigned long ppc_proc_freq;
unsigned long ppc_tb_freq;
@@ -178,8 +183,7 @@ static __inline__ void timer_check_rtc(void)
*/
if (ppc_md.set_rtc_time && ntp_synced() &&
xtime.tv_sec - last_rtc_update >= 659 &&
- abs((xtime.tv_nsec/1000) - (1000000-1000000/HZ)) < 500000/HZ &&
- jiffies - wall_jiffies == 1) {
+ abs((xtime.tv_nsec/1000) - (1000000-1000000/HZ)) < 500000/HZ) {
struct rtc_time tm;
to_tm(xtime.tv_sec + 1 + timezone_offset, &tm);
tm.tm_year -= 1900;
@@ -226,15 +230,14 @@ void do_gettimeofday(struct timeval *tv)
if (__USE_RTC()) {
/* do this the old way */
unsigned long flags, seq;
- unsigned int sec, nsec, usec, lost;
+ unsigned int sec, nsec, usec;
do {
seq = read_seqbegin_irqsave(&xtime_lock, flags);
sec = xtime.tv_sec;
nsec = xtime.tv_nsec + tb_ticks_since(tb_last_stamp);
- lost = jiffies - wall_jiffies;
} while (read_seqretry_irqrestore(&xtime_lock, seq, flags));
- usec = nsec / 1000 + lost * (1000000 / HZ);
+ usec = nsec / 1000;
while (usec >= 1000000) {
usec -= 1000000;
++sec;
@@ -248,23 +251,6 @@ void do_gettimeofday(struct timeval *tv)
EXPORT_SYMBOL(do_gettimeofday);
-/* Synchronize xtime with do_gettimeofday */
-
-static inline void timer_sync_xtime(unsigned long cur_tb)
-{
-#ifdef CONFIG_PPC64
- /* why do we do this? */
- struct timeval my_tv;
-
- __do_gettimeofday(&my_tv, cur_tb);
-
- if (xtime.tv_sec <= my_tv.tv_sec) {
- xtime.tv_sec = my_tv.tv_sec;
- xtime.tv_nsec = my_tv.tv_usec * 1000;
- }
-#endif
-}
-
/*
* There are two copies of tb_to_xs and stamp_xsec so that no
* lock is needed to access and use these values in
@@ -323,15 +309,30 @@ static __inline__ void timer_recalc_offset(u64 cur_tb)
{
unsigned long offset;
u64 new_stamp_xsec;
+ u64 tlen, t2x;
if (__USE_RTC())
return;
+ tlen = current_tick_length();
offset = cur_tb - do_gtod.varp->tb_orig_stamp;
- if ((offset & 0x80000000u) == 0)
- return;
- new_stamp_xsec = do_gtod.varp->stamp_xsec
- + mulhdu(offset, do_gtod.varp->tb_to_xs);
- update_gtod(cur_tb, new_stamp_xsec, do_gtod.varp->tb_to_xs);
+ if (tlen == last_tick_len && offset < 0x80000000u) {
+ /* check that we're still in sync; if not, resync */
+ struct timeval tv;
+ __do_gettimeofday(&tv, cur_tb);
+ if (tv.tv_sec <= xtime.tv_sec &&
+ (tv.tv_sec < xtime.tv_sec ||
+ tv.tv_usec * 1000 <= xtime.tv_nsec))
+ return;
+ }
+ if (tlen != last_tick_len) {
+ t2x = mulhdu(tlen << TICKLEN_SHIFT, ticklen_to_xs);
+ last_tick_len = tlen;
+ } else
+ t2x = do_gtod.varp->tb_to_xs;
+ new_stamp_xsec = (u64) xtime.tv_nsec * XSEC_PER_SEC;
+ do_div(new_stamp_xsec, 1000000000);
+ new_stamp_xsec += (u64) xtime.tv_sec * XSEC_PER_SEC;
+ update_gtod(cur_tb, new_stamp_xsec, t2x);
}
#ifdef CONFIG_SMP
@@ -462,13 +463,10 @@ void timer_interrupt(struct pt_regs * regs)
write_seqlock(&xtime_lock);
tb_last_jiffy += tb_ticks_per_jiffy;
tb_last_stamp = per_cpu(last_jiffy, cpu);
- timer_recalc_offset(tb_last_jiffy);
do_timer(regs);
- timer_sync_xtime(tb_last_jiffy);
+ timer_recalc_offset(tb_last_jiffy);
timer_check_rtc();
write_sequnlock(&xtime_lock);
- if (adjusting_time && (time_adjust == 0))
- ppc_adjtimex();
}
next_dec = tb_ticks_per_jiffy - ticks;
@@ -492,16 +490,18 @@ void timer_interrupt(struct pt_regs * regs)
void wakeup_decrementer(void)
{
- int i;
+ unsigned long ticks;
- set_dec(tb_ticks_per_jiffy);
/*
- * We don't expect this to be called on a machine with a 601,
- * so using get_tbl is fine.
+ * The timebase gets saved on sleep and restored on wakeup,
+ * so all we need to do is to reset the decrementer.
*/
- tb_last_stamp = tb_last_jiffy = get_tb();
- for_each_cpu(i)
- per_cpu(last_jiffy, i) = tb_last_stamp;
+ ticks = tb_ticks_since(__get_cpu_var(last_jiffy));
+ if (ticks < tb_ticks_per_jiffy)
+ ticks = tb_ticks_per_jiffy - ticks;
+ else
+ ticks = 1;
+ set_dec(ticks);
}
#ifdef CONFIG_SMP
@@ -541,8 +541,8 @@ int do_settimeofday(struct timespec *tv)
time_t wtm_sec, new_sec = tv->tv_sec;
long wtm_nsec, new_nsec = tv->tv_nsec;
unsigned long flags;
- long int tb_delta;
- u64 new_xsec, tb_delta_xs;
+ u64 new_xsec;
+ unsigned long tb_delta;
if ((unsigned long)tv->tv_nsec >= NSEC_PER_SEC)
return -EINVAL;
@@ -563,9 +563,19 @@ int do_settimeofday(struct timespec *tv)
first_settimeofday = 0;
}
#endif
+
+ /*
+ * Subtract off the number of nanoseconds since the
+ * beginning of the last tick.
+ * Note that since we don't increment jiffies_64 anywhere other
+ * than in do_timer (since we don't have a lost tick problem),
+ * wall_jiffies will always be the same as jiffies,
+ * and therefore the (jiffies - wall_jiffies) computation
+ * has been removed.
+ */
tb_delta = tb_ticks_since(tb_last_stamp);
- tb_delta += (jiffies - wall_jiffies) * tb_ticks_per_jiffy;
- tb_delta_xs = mulhdu(tb_delta, do_gtod.varp->tb_to_xs);
+ tb_delta = mulhdu(tb_delta, do_gtod.varp->tb_to_xs); /* in xsec */
+ new_nsec -= SCALE_XSEC(tb_delta, 1000000000);
wtm_sec = wall_to_monotonic.tv_sec + (xtime.tv_sec - new_sec);
wtm_nsec = wall_to_monotonic.tv_nsec + (xtime.tv_nsec - new_nsec);
@@ -580,12 +590,12 @@ int do_settimeofday(struct timespec *tv)
ntp_clear();
- new_xsec = 0;
- if (new_nsec != 0) {
- new_xsec = (u64)new_nsec * XSEC_PER_SEC;
+ new_xsec = xtime.tv_nsec;
+ if (new_xsec != 0) {
+ new_xsec *= XSEC_PER_SEC;
do_div(new_xsec, NSEC_PER_SEC);
}
- new_xsec += (u64)new_sec * XSEC_PER_SEC - tb_delta_xs;
+ new_xsec += (u64)xtime.tv_sec * XSEC_PER_SEC;
update_gtod(tb_last_jiffy, new_xsec, do_gtod.varp->tb_to_xs);
vdso_data->tz_minuteswest = sys_tz.tz_minuteswest;
@@ -671,7 +681,7 @@ void __init time_init(void)
unsigned long flags;
unsigned long tm = 0;
struct div_result res;
- u64 scale;
+ u64 scale, x;
unsigned shift;
if (ppc_md.time_init != NULL)
@@ -693,11 +703,36 @@ void __init time_init(void)
}
tb_ticks_per_jiffy = ppc_tb_freq / HZ;
- tb_ticks_per_sec = tb_ticks_per_jiffy * HZ;
+ tb_ticks_per_sec = ppc_tb_freq;
tb_ticks_per_usec = ppc_tb_freq / 1000000;
tb_to_us = mulhwu_scale_factor(ppc_tb_freq, 1000000);
- div128_by_32(1024*1024, 0, tb_ticks_per_sec, &res);
- tb_to_xs = res.result_low;
+
+ /*
+ * Calculate the length of each tick in ns. It will not be
+ * exactly 1e9/HZ unless ppc_tb_freq is divisible by HZ.
+ * We compute 1e9 * tb_ticks_per_jiffy / ppc_tb_freq,
+ * rounded up.
+ */
+ x = (u64) NSEC_PER_SEC * tb_ticks_per_jiffy + ppc_tb_freq - 1;
+ do_div(x, ppc_tb_freq);
+ tick_nsec = x;
+ last_tick_len = x << TICKLEN_SCALE;
+
+ /*
+ * Compute ticklen_to_xs, which is a factor which gets multiplied
+ * by (last_tick_len << TICKLEN_SHIFT) to get a tb_to_xs value.
+ * It is computed as:
+ * ticklen_to_xs = 2^N / (tb_ticks_per_jiffy * 1e9)
+ * where N = 64 + 20 - TICKLEN_SCALE - TICKLEN_SHIFT
+ * so as to give the result as a 0.64 fixed-point fraction.
+ */
+ div128_by_32(1ULL << (64 + 20 - TICKLEN_SCALE - TICKLEN_SHIFT), 0,
+ tb_ticks_per_jiffy, &res);
+ div128_by_32(res.result_high, res.result_low, NSEC_PER_SEC, &res);
+ ticklen_to_xs = res.result_low;
+
+ /* Compute tb_to_xs from tick_nsec */
+ tb_to_xs = mulhdu(last_tick_len << TICKLEN_SHIFT, ticklen_to_xs);
/*
* Compute scale factor for sched_clock.
@@ -724,6 +759,14 @@ void __init time_init(void)
tm = get_boot_time();
write_seqlock_irqsave(&xtime_lock, flags);
+
+ /* If platform provided a timezone (pmac), we correct the time */
+ if (timezone_offset) {
+ sys_tz.tz_minuteswest = -timezone_offset / 60;
+ sys_tz.tz_dsttime = 0;
+ tm -= timezone_offset;
+ }
+
xtime.tv_sec = tm;
xtime.tv_nsec = 0;
do_gtod.varp = &do_gtod.vars[0];
@@ -738,18 +781,11 @@ void __init time_init(void)
vdso_data->tb_orig_stamp = tb_last_jiffy;
vdso_data->tb_update_count = 0;
vdso_data->tb_ticks_per_sec = tb_ticks_per_sec;
- vdso_data->stamp_xsec = xtime.tv_sec * XSEC_PER_SEC;
+ vdso_data->stamp_xsec = (u64) xtime.tv_sec * XSEC_PER_SEC;
vdso_data->tb_to_xs = tb_to_xs;
time_freq = 0;
- /* If platform provided a timezone (pmac), we correct the time */
- if (timezone_offset) {
- sys_tz.tz_minuteswest = -timezone_offset / 60;
- sys_tz.tz_dsttime = 0;
- xtime.tv_sec -= timezone_offset;
- }
-
last_rtc_update = xtime.tv_sec;
set_normalized_timespec(&wall_to_monotonic,
-xtime.tv_sec, -xtime.tv_nsec);
@@ -759,126 +795,6 @@ void __init time_init(void)
set_dec(tb_ticks_per_jiffy);
}
-/*
- * After adjtimex is called, adjust the conversion of tb ticks
- * to microseconds to keep do_gettimeofday synchronized
- * with ntpd.
- *
- * Use the time_adjust, time_freq and time_offset computed by adjtimex to
- * adjust the frequency.
- */
-
-/* #define DEBUG_PPC_ADJTIMEX 1 */
-
-void ppc_adjtimex(void)
-{
-#ifdef CONFIG_PPC64
- unsigned long den, new_tb_ticks_per_sec, tb_ticks, old_xsec,
- new_tb_to_xs, new_xsec, new_stamp_xsec;
- unsigned long tb_ticks_per_sec_delta;
- long delta_freq, ltemp;
- struct div_result divres;
- unsigned long flags;
- long singleshot_ppm = 0;
-
- /*
- * Compute parts per million frequency adjustment to
- * accomplish the time adjustment implied by time_offset to be
- * applied over the elapsed time indicated by time_constant.
- * Use SHIFT_USEC to get it into the same units as
- * time_freq.
- */
- if ( time_offset < 0 ) {
- ltemp = -time_offset;
- ltemp <<= SHIFT_USEC - SHIFT_UPDATE;
- ltemp >>= SHIFT_KG + time_constant;
- ltemp = -ltemp;
- } else {
- ltemp = time_offset;
- ltemp <<= SHIFT_USEC - SHIFT_UPDATE;
- ltemp >>= SHIFT_KG + time_constant;
- }
-
- /* If there is a single shot time adjustment in progress */
- if ( time_adjust ) {
-#ifdef DEBUG_PPC_ADJTIMEX
- printk("ppc_adjtimex: ");
- if ( adjusting_time == 0 )
- printk("starting ");
- printk("single shot time_adjust = %ld\n", time_adjust);
-#endif
-
- adjusting_time = 1;
-
- /*
- * Compute parts per million frequency adjustment
- * to match time_adjust
- */
- singleshot_ppm = tickadj * HZ;
- /*
- * The adjustment should be tickadj*HZ to match the code in
- * linux/kernel/timer.c, but experiments show that this is too
- * large. 3/4 of tickadj*HZ seems about right
- */
- singleshot_ppm -= singleshot_ppm / 4;
- /* Use SHIFT_USEC to get it into the same units as time_freq */
- singleshot_ppm <<= SHIFT_USEC;
- if ( time_adjust < 0 )
- singleshot_ppm = -singleshot_ppm;
- }
- else {
-#ifdef DEBUG_PPC_ADJTIMEX
- if ( adjusting_time )
- printk("ppc_adjtimex: ending single shot time_adjust\n");
-#endif
- adjusting_time = 0;
- }
-
- /* Add up all of the frequency adjustments */
- delta_freq = time_freq + ltemp + singleshot_ppm;
-
- /*
- * Compute a new value for tb_ticks_per_sec based on
- * the frequency adjustment
- */
- den = 1000000 * (1 << (SHIFT_USEC - 8));
- if ( delta_freq < 0 ) {
- tb_ticks_per_sec_delta = ( tb_ticks_per_sec * ( (-delta_freq) >> (SHIFT_USEC - 8))) / den;
- new_tb_ticks_per_sec = tb_ticks_per_sec + tb_ticks_per_sec_delta;
- }
- else {
- tb_ticks_per_sec_delta = ( tb_ticks_per_sec * ( delta_freq >> (SHIFT_USEC - 8))) / den;
- new_tb_ticks_per_sec = tb_ticks_per_sec - tb_ticks_per_sec_delta;
- }
-
-#ifdef DEBUG_PPC_ADJTIMEX
- printk("ppc_adjtimex: ltemp = %ld, time_freq = %ld, singleshot_ppm = %ld\n", ltemp, time_freq, singleshot_ppm);
- printk("ppc_adjtimex: tb_ticks_per_sec - base = %ld new = %ld\n", tb_ticks_per_sec, new_tb_ticks_per_sec);
-#endif
-
- /*
- * Compute a new value of tb_to_xs (used to convert tb to
- * microseconds) and a new value of stamp_xsec which is the
- * time (in 1/2^20 second units) corresponding to
- * tb_orig_stamp. This new value of stamp_xsec compensates
- * for the change in frequency (implied by the new tb_to_xs)
- * which guarantees that the current time remains the same.
- */
- write_seqlock_irqsave( &xtime_lock, flags );
- tb_ticks = get_tb() - do_gtod.varp->tb_orig_stamp;
- div128_by_32(1024*1024, 0, new_tb_ticks_per_sec, &divres);
- new_tb_to_xs = divres.result_low;
- new_xsec = mulhdu(tb_ticks, new_tb_to_xs);
-
- old_xsec = mulhdu(tb_ticks, do_gtod.varp->tb_to_xs);
- new_stamp_xsec = do_gtod.varp->stamp_xsec + old_xsec - new_xsec;
-
- update_gtod(do_gtod.varp->tb_orig_stamp, new_stamp_xsec, new_tb_to_xs);
-
- write_sequnlock_irqrestore( &xtime_lock, flags );
-#endif /* CONFIG_PPC64 */
-}
-
#define FEBRUARY 2
#define STARTOFTIME 1970
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