diff options
Diffstat (limited to 'arch/powerpc/kernel/time.c')
| -rw-r--r-- | arch/powerpc/kernel/time.c | 136 |
1 files changed, 3 insertions, 133 deletions
diff --git a/arch/powerpc/kernel/time.c b/arch/powerpc/kernel/time.c index 5adebaf47f13..ccb8759c8532 100644 --- a/arch/powerpc/kernel/time.c +++ b/arch/powerpc/kernel/time.c @@ -149,16 +149,6 @@ unsigned long tb_ticks_per_usec = 100; /* sane default */ EXPORT_SYMBOL(tb_ticks_per_usec); unsigned long tb_ticks_per_sec; EXPORT_SYMBOL(tb_ticks_per_sec); /* for cputime_t conversions */ -u64 tb_to_xs; -unsigned tb_to_us; - -#define TICKLEN_SCALE NTP_SCALE_SHIFT -static u64 last_tick_len; /* units are ns / 2^TICKLEN_SCALE */ -static 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); @@ -174,7 +164,6 @@ unsigned long ppc_proc_freq; EXPORT_SYMBOL(ppc_proc_freq); unsigned long ppc_tb_freq; -static u64 tb_last_jiffy __cacheline_aligned_in_smp; static DEFINE_PER_CPU(u64, last_jiffy); #ifdef CONFIG_VIRT_CPU_ACCOUNTING @@ -446,7 +435,6 @@ EXPORT_SYMBOL(profile_pc); static int __init iSeries_tb_recal(void) { - struct div_result divres; unsigned long titan, tb; /* Make sure we only run on iSeries */ @@ -477,10 +465,7 @@ static int __init iSeries_tb_recal(void) tb_ticks_per_jiffy = new_tb_ticks_per_jiffy; tb_ticks_per_sec = new_tb_ticks_per_sec; calc_cputime_factors(); - div128_by_32( XSEC_PER_SEC, 0, tb_ticks_per_sec, &divres ); - tb_to_xs = divres.result_low; vdso_data->tb_ticks_per_sec = tb_ticks_per_sec; - vdso_data->tb_to_xs = tb_to_xs; setup_cputime_one_jiffy(); } else { @@ -643,27 +628,9 @@ void timer_interrupt(struct pt_regs * regs) trace_timer_interrupt_exit(regs); } -void wakeup_decrementer(void) -{ - unsigned long ticks; - - /* - * The timebase gets saved on sleep and restored on wakeup, - * so all we need to do is to reset the decrementer. - */ - 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_SUSPEND -void generic_suspend_disable_irqs(void) +static void generic_suspend_disable_irqs(void) { - preempt_disable(); - /* Disable the decrementer, so that it doesn't interfere * with suspending. */ @@ -673,12 +640,9 @@ void generic_suspend_disable_irqs(void) set_dec(0x7fffffff); } -void generic_suspend_enable_irqs(void) +static void generic_suspend_enable_irqs(void) { - wakeup_decrementer(); - local_irq_enable(); - preempt_enable(); } /* Overrides the weak version in kernel/power/main.c */ @@ -698,23 +662,6 @@ void arch_suspend_enable_irqs(void) } #endif -#ifdef CONFIG_SMP -void __init smp_space_timers(unsigned int max_cpus) -{ - int i; - u64 previous_tb = per_cpu(last_jiffy, boot_cpuid); - - /* make sure tb > per_cpu(last_jiffy, cpu) for all cpus always */ - previous_tb -= tb_ticks_per_jiffy; - - for_each_possible_cpu(i) { - if (i == boot_cpuid) - continue; - per_cpu(last_jiffy, i) = previous_tb; - } -} -#endif - /* * Scheduler clock - returns current time in nanosec units. * @@ -1014,15 +961,13 @@ void secondary_cpu_time_init(void) /* This function is only called on the boot processor */ void __init time_init(void) { - unsigned long flags; struct div_result res; - u64 scale, x; + u64 scale; unsigned shift; if (__USE_RTC()) { /* 601 processor: dec counts down by 128 every 128ns */ ppc_tb_freq = 1000000000; - tb_last_jiffy = get_rtcl(); } else { /* Normal PowerPC with timebase register */ ppc_md.calibrate_decr(); @@ -1030,50 +975,15 @@ void __init time_init(void) ppc_tb_freq / 1000000, ppc_tb_freq % 1000000); printk(KERN_DEBUG "time_init: processor frequency = %lu.%.6lu MHz\n", ppc_proc_freq / 1000000, ppc_proc_freq % 1000000); - tb_last_jiffy = get_tb(); } tb_ticks_per_jiffy = ppc_tb_freq / 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); calc_cputime_factors(); setup_cputime_one_jiffy(); /* - * 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 - * which turns out to be N = 51 - SHIFT_HZ. - * This gives the result as a 0.64 fixed-point fraction. - * That value is reduced by an offset amounting to 1 xsec per - * 2^31 timebase ticks to avoid problems with time going backwards - * by 1 xsec when we do timer_recalc_offset due to losing the - * fractional xsec. That offset is equal to ppc_tb_freq/2^51 - * since there are 2^20 xsec in a second. - */ - div128_by_32((1ULL << 51) - ppc_tb_freq, 0, - tb_ticks_per_jiffy << SHIFT_HZ, &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. * The calibrate_decr() function has set tb_ticks_per_sec, * which is the timebase frequency. @@ -1094,21 +1004,14 @@ void __init time_init(void) /* Save the current timebase to pretty up CONFIG_PRINTK_TIME */ boot_tb = get_tb_or_rtc(); - 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; } - 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 = (u64) xtime.tv_sec * XSEC_PER_SEC; - vdso_data->tb_to_xs = tb_to_xs; - - write_sequnlock_irqrestore(&xtime_lock, flags); /* Start the decrementer on CPUs that have manual control * such as BookE @@ -1202,39 +1105,6 @@ void to_tm(int tim, struct rtc_time * tm) GregorianDay(tm); } -/* Auxiliary function to compute scaling factors */ -/* Actually the choice of a timebase running at 1/4 the of the bus - * frequency giving resolution of a few tens of nanoseconds is quite nice. - * It makes this computation very precise (27-28 bits typically) which - * is optimistic considering the stability of most processor clock - * oscillators and the precision with which the timebase frequency - * is measured but does not harm. - */ -unsigned mulhwu_scale_factor(unsigned inscale, unsigned outscale) -{ - unsigned mlt=0, tmp, err; - /* No concern for performance, it's done once: use a stupid - * but safe and compact method to find the multiplier. - */ - - for (tmp = 1U<<31; tmp != 0; tmp >>= 1) { - if (mulhwu(inscale, mlt|tmp) < outscale) - mlt |= tmp; - } - - /* We might still be off by 1 for the best approximation. - * A side effect of this is that if outscale is too large - * the returned value will be zero. - * Many corner cases have been checked and seem to work, - * some might have been forgotten in the test however. - */ - - err = inscale * (mlt+1); - if (err <= inscale/2) - mlt++; - return mlt; -} - /* * Divide a 128-bit dividend by a 32-bit divisor, leaving a 128 bit * result. |