diff options
author | Dave Kleikamp <shaggy@austin.ibm.com> | 2006-03-14 17:05:45 -0600 |
---|---|---|
committer | Dave Kleikamp <shaggy@austin.ibm.com> | 2006-03-14 17:05:45 -0600 |
commit | c5111f504d2a9b0d258d7c4752b4093523315989 (patch) | |
tree | 6a52864aff79691689aea21cb0cb928327d5de5b /arch/powerpc/kernel/time.c | |
parent | 69eb66d7da7dba2696281981347698e1693c2340 (diff) | |
parent | a488edc914aa1d766a4e2c982b5ae03d5657ec1b (diff) |
Merge with /home/shaggy/git/linus-clean/
Diffstat (limited to 'arch/powerpc/kernel/time.c')
-rw-r--r-- | arch/powerpc/kernel/time.c | 290 |
1 files changed, 103 insertions, 187 deletions
diff --git a/arch/powerpc/kernel/time.c b/arch/powerpc/kernel/time.c index c4a294d657b..2a7ddc57937 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; @@ -612,10 +622,10 @@ void __init generic_calibrate_decr(void) ppc_tb_freq = DEFAULT_TB_FREQ; /* hardcoded default */ node_found = 0; - if (cpu != 0) { + if (cpu) { fp = (unsigned int *)get_property(cpu, "timebase-frequency", NULL); - if (fp != 0) { + if (fp) { node_found = 1; ppc_tb_freq = *fp; } @@ -626,10 +636,10 @@ void __init generic_calibrate_decr(void) ppc_proc_freq = DEFAULT_PROC_FREQ; node_found = 0; - if (cpu != 0) { + if (cpu) { fp = (unsigned int *)get_property(cpu, "clock-frequency", NULL); - if (fp != 0) { + if (fp) { node_found = 1; ppc_proc_freq = *fp; } @@ -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 |