1 files changed, 99 insertions, 183 deletions

diff --git a/arch/powerpc/kernel/time.c b/arch/powerpc/kernel/time.c
index 1886045a2fd8..2a7ddc579379 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