Early pass on powerpc conversion to generic timekeeping. Signed-off-by: John Stultz arch/powerpc/Kconfig | 4 arch/powerpc/kernel/time.c | 272 +++++---------------------------------------- 2 files changed, 37 insertions(+), 239 deletions(-) linux-2.6.18-rc6_timeofday-arch-ppc_C6.patch ============================================ Index: work-powerpc.git/arch/powerpc/Kconfig =================================================================== --- work-powerpc.git.orig/arch/powerpc/Kconfig +++ work-powerpc.git/arch/powerpc/Kconfig @@ -21,6 +21,10 @@ config MMU bool default y +config GENERIC_TIME + bool + default y + config GENERIC_HARDIRQS bool default y Index: work-powerpc.git/arch/powerpc/kernel/time.c =================================================================== --- work-powerpc.git.orig/arch/powerpc/kernel/time.c +++ work-powerpc.git/arch/powerpc/kernel/time.c @@ -117,8 +117,6 @@ static u64 tb_to_ns_scale __read_mostly; static unsigned tb_to_ns_shift __read_mostly; static unsigned long boot_tb __read_mostly; -struct gettimeofday_struct do_gtod; - extern struct timezone sys_tz; static long timezone_offset; @@ -462,160 +460,6 @@ static __inline__ void timer_check_rtc(v } } -/* - * This version of gettimeofday has microsecond resolution. - */ -static inline void __do_gettimeofday(struct timeval *tv) -{ - unsigned long sec, usec; - u64 tb_ticks, xsec; - struct gettimeofday_vars *temp_varp; - u64 temp_tb_to_xs, temp_stamp_xsec; - - /* - * These calculations are faster (gets rid of divides) - * if done in units of 1/2^20 rather than microseconds. - * The conversion to microseconds at the end is done - * without a divide (and in fact, without a multiply) - */ - temp_varp = do_gtod.varp; - - /* Sampling the time base must be done after loading - * do_gtod.varp in order to avoid racing with update_gtod. - */ - data_barrier(temp_varp); - tb_ticks = get_tb() - temp_varp->tb_orig_stamp; - temp_tb_to_xs = temp_varp->tb_to_xs; - temp_stamp_xsec = temp_varp->stamp_xsec; - xsec = temp_stamp_xsec + mulhdu(tb_ticks, temp_tb_to_xs); - sec = xsec / XSEC_PER_SEC; - usec = (unsigned long)xsec & (XSEC_PER_SEC - 1); - usec = SCALE_XSEC(usec, 1000000); - - tv->tv_sec = sec; - tv->tv_usec = usec; -} - -void do_gettimeofday(struct timeval *tv) -{ - if (__USE_RTC()) { - /* do this the old way */ - unsigned long flags, seq; - 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_jiffy); - } while (read_seqretry_irqrestore(&xtime_lock, seq, flags)); - usec = nsec / 1000; - while (usec >= 1000000) { - usec -= 1000000; - ++sec; - } - tv->tv_sec = sec; - tv->tv_usec = usec; - return; - } - __do_gettimeofday(tv); -} - -EXPORT_SYMBOL(do_gettimeofday); - -/* - * There are two copies of tb_to_xs and stamp_xsec so that no - * lock is needed to access and use these values in - * do_gettimeofday. We alternate the copies and as long as a - * reasonable time elapses between changes, there will never - * be inconsistent values. ntpd has a minimum of one minute - * between updates. - */ -static inline void update_gtod(u64 new_tb_stamp, u64 new_stamp_xsec, - u64 new_tb_to_xs) -{ - unsigned temp_idx; - struct gettimeofday_vars *temp_varp; - - temp_idx = (do_gtod.var_idx == 0); - temp_varp = &do_gtod.vars[temp_idx]; - - temp_varp->tb_to_xs = new_tb_to_xs; - temp_varp->tb_orig_stamp = new_tb_stamp; - temp_varp->stamp_xsec = new_stamp_xsec; - smp_mb(); - do_gtod.varp = temp_varp; - do_gtod.var_idx = temp_idx; - - /* - * tb_update_count is used to allow the userspace gettimeofday code - * to assure itself that it sees a consistent view of the tb_to_xs and - * stamp_xsec variables. It reads the tb_update_count, then reads - * tb_to_xs and stamp_xsec and then reads tb_update_count again. If - * the two values of tb_update_count match and are even then the - * tb_to_xs and stamp_xsec values are consistent. If not, then it - * loops back and reads them again until this criteria is met. - * We expect the caller to have done the first increment of - * vdso_data->tb_update_count already. - */ - vdso_data->tb_orig_stamp = new_tb_stamp; - vdso_data->stamp_xsec = new_stamp_xsec; - vdso_data->tb_to_xs = new_tb_to_xs; - vdso_data->wtom_clock_sec = wall_to_monotonic.tv_sec; - vdso_data->wtom_clock_nsec = wall_to_monotonic.tv_nsec; - smp_wmb(); - ++(vdso_data->tb_update_count); -} - -/* - * When the timebase - tb_orig_stamp gets too big, we do a manipulation - * between tb_orig_stamp and stamp_xsec. The goal here is to keep the - * difference tb - tb_orig_stamp small enough to always fit inside a - * 32 bits number. This is a requirement of our fast 32 bits userland - * implementation in the vdso. If we "miss" a call to this function - * (interrupt latency, CPU locked in a spinlock, ...) and we end up - * with a too big difference, then the vdso will fallback to calling - * the syscall - */ -static __inline__ void timer_recalc_offset(u64 cur_tb) -{ - unsigned long offset; - u64 new_stamp_xsec; - u64 tlen, t2x; - u64 tb, xsec_old, xsec_new; - struct gettimeofday_vars *varp; - - if (__USE_RTC()) - return; - tlen = current_tick_length(); - offset = cur_tb - do_gtod.varp->tb_orig_stamp; - if (tlen == last_tick_len && offset < 0x80000000u) - 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; - - ++vdso_data->tb_update_count; - smp_mb(); - - /* - * Make sure time doesn't go backwards for userspace gettimeofday. - */ - tb = get_tb(); - varp = do_gtod.varp; - xsec_old = mulhdu(tb - varp->tb_orig_stamp, varp->tb_to_xs) - + varp->stamp_xsec; - xsec_new = mulhdu(tb - cur_tb, t2x) + new_stamp_xsec; - if (xsec_new < xsec_old) - new_stamp_xsec += xsec_old - xsec_new; - - update_gtod(cur_tb, new_stamp_xsec, t2x); -} - #ifdef CONFIG_SMP unsigned long profile_pc(struct pt_regs *regs) { @@ -670,11 +514,7 @@ static int __init iSeries_tb_recal(void) tb_ticks_per_sec = new_tb_ticks_per_sec; calc_cputime_factors(); div128_by_32( XSEC_PER_SEC, 0, tb_ticks_per_sec, &divres ); - do_gtod.tb_ticks_per_sec = tb_ticks_per_sec; tb_to_xs = divres.result_low; - do_gtod.varp->tb_to_xs = tb_to_xs; - vdso_data->tb_ticks_per_sec = tb_ticks_per_sec; - vdso_data->tb_to_xs = tb_to_xs; } else { printk( "Titan recalibrate: FAILED (difference > 4 percent)\n" @@ -870,70 +710,6 @@ unsigned long long sched_clock(void) return mulhdu(get_tb() - boot_tb, tb_to_ns_scale) << tb_to_ns_shift; } -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; - u64 new_xsec; - unsigned long tb_delta; - - if ((unsigned long)tv->tv_nsec >= NSEC_PER_SEC) - return -EINVAL; - - write_seqlock_irqsave(&xtime_lock, flags); - - /* - * Updating the RTC is not the job of this code. If the time is - * stepped under NTP, the RTC will be updated after STA_UNSYNC - * is cleared. Tools like clock/hwclock either copy the RTC - * to the system time, in which case there is no point in writing - * to the RTC again, or write to the RTC but then they don't call - * settimeofday to perform this operation. - */ - - /* Make userspace gettimeofday spin until we're done. */ - ++vdso_data->tb_update_count; - smp_mb(); - - /* - * Subtract off the number of nanoseconds since the - * beginning of the last tick. - */ - tb_delta = tb_ticks_since(tb_last_jiffy); - 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); - - set_normalized_timespec(&xtime, new_sec, new_nsec); - set_normalized_timespec(&wall_to_monotonic, wtm_sec, wtm_nsec); - - /* In case of a large backwards jump in time with NTP, we want the - * clock to be updated as soon as the PLL is again in lock. - */ - last_rtc_update = new_sec - 658; - - ntp_clear(); - - new_xsec = xtime.tv_nsec; - if (new_xsec != 0) { - new_xsec *= XSEC_PER_SEC; - do_div(new_xsec, NSEC_PER_SEC); - } - 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; - vdso_data->tz_dsttime = sys_tz.tz_dsttime; - - write_sequnlock_irqrestore(&xtime_lock, flags); - clock_was_set(); - return 0; -} - -EXPORT_SYMBOL(do_settimeofday); static int __init get_freq(char *name, int cells, unsigned long *val) { @@ -1102,20 +878,6 @@ void __init time_init(void) xtime.tv_sec = tm; xtime.tv_nsec = 0; - do_gtod.varp = &do_gtod.vars[0]; - do_gtod.var_idx = 0; - do_gtod.varp->tb_orig_stamp = tb_last_jiffy; - __get_cpu_var(last_jiffy) = tb_last_jiffy; - do_gtod.varp->stamp_xsec = (u64) xtime.tv_sec * XSEC_PER_SEC; - do_gtod.tb_ticks_per_sec = tb_ticks_per_sec; - do_gtod.varp->tb_to_xs = tb_to_xs; - do_gtod.tb_to_us = tb_to_us; - - 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; time_freq = 0; @@ -1139,7 +901,6 @@ void __init time_init(void) #endif } - #define FEBRUARY 2 #define STARTOFTIME 1970 #define SECDAY 86400L @@ -1284,3 +1045,36 @@ void div128_by_32(u64 dividend_high, u64 dr->result_low = ((u64)y << 32) + z; } + + +/* powerpc clocksource code */ + +#include +static cycle_t timebase_read(void) +{ + return (cycle_t)get_tb(); +} + +struct clocksource clocksource_timebase = { + .name = "timebase", + .rating = 200, + .read = timebase_read, + .mask = (cycle_t)-1, + .mult = 0, + .shift = 22, +}; + + +/* XXX - this should be calculated or properly externed! */ +static int __init init_timebase_clocksource(void) +{ + if (__USE_RTC()) + return -ENODEV; + + clocksource_timebase.mult = clocksource_hz2mult(tb_ticks_per_sec, + clocksource_timebase.shift); + return clocksource_register(&clocksource_timebase); +} + +module_init(init_timebase_clocksource); +