diff options
author | Linus Torvalds <torvalds@ppc970.osdl.org> | 2005-04-16 15:20:36 -0700 |
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committer | Linus Torvalds <torvalds@ppc970.osdl.org> | 2005-04-16 15:20:36 -0700 |
commit | 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 (patch) | |
tree | 0bba044c4ce775e45a88a51686b5d9f90697ea9d /arch/s390/kernel/time.c |
Linux-2.6.12-rc2
Initial git repository build. I'm not bothering with the full history,
even though we have it. We can create a separate "historical" git
archive of that later if we want to, and in the meantime it's about
3.2GB when imported into git - space that would just make the early
git days unnecessarily complicated, when we don't have a lot of good
infrastructure for it.
Let it rip!
Diffstat (limited to 'arch/s390/kernel/time.c')
-rw-r--r-- | arch/s390/kernel/time.c | 382 |
1 files changed, 382 insertions, 0 deletions
diff --git a/arch/s390/kernel/time.c b/arch/s390/kernel/time.c new file mode 100644 index 00000000000..061e81138dc --- /dev/null +++ b/arch/s390/kernel/time.c @@ -0,0 +1,382 @@ +/* + * arch/s390/kernel/time.c + * Time of day based timer functions. + * + * S390 version + * Copyright (C) 1999 IBM Deutschland Entwicklung GmbH, IBM Corporation + * Author(s): Hartmut Penner (hp@de.ibm.com), + * Martin Schwidefsky (schwidefsky@de.ibm.com), + * Denis Joseph Barrow (djbarrow@de.ibm.com,barrow_dj@yahoo.com) + * + * Derived from "arch/i386/kernel/time.c" + * Copyright (C) 1991, 1992, 1995 Linus Torvalds + */ + +#include <linux/config.h> +#include <linux/errno.h> +#include <linux/module.h> +#include <linux/sched.h> +#include <linux/kernel.h> +#include <linux/param.h> +#include <linux/string.h> +#include <linux/mm.h> +#include <linux/interrupt.h> +#include <linux/time.h> +#include <linux/delay.h> +#include <linux/init.h> +#include <linux/smp.h> +#include <linux/types.h> +#include <linux/profile.h> +#include <linux/timex.h> +#include <linux/notifier.h> + +#include <asm/uaccess.h> +#include <asm/delay.h> +#include <asm/s390_ext.h> +#include <asm/div64.h> +#include <asm/irq.h> +#include <asm/timer.h> + +/* change this if you have some constant time drift */ +#define USECS_PER_JIFFY ((unsigned long) 1000000/HZ) +#define CLK_TICKS_PER_JIFFY ((unsigned long) USECS_PER_JIFFY << 12) + +/* + * Create a small time difference between the timer interrupts + * on the different cpus to avoid lock contention. + */ +#define CPU_DEVIATION (smp_processor_id() << 12) + +#define TICK_SIZE tick + +u64 jiffies_64 = INITIAL_JIFFIES; + +EXPORT_SYMBOL(jiffies_64); + +static ext_int_info_t ext_int_info_cc; +static u64 init_timer_cc; +static u64 jiffies_timer_cc; +static u64 xtime_cc; + +extern unsigned long wall_jiffies; + +/* + * Scheduler clock - returns current time in nanosec units. + */ +unsigned long long sched_clock(void) +{ + return ((get_clock() - jiffies_timer_cc) * 1000) >> 12; +} + +void tod_to_timeval(__u64 todval, struct timespec *xtime) +{ + unsigned long long sec; + + sec = todval >> 12; + do_div(sec, 1000000); + xtime->tv_sec = sec; + todval -= (sec * 1000000) << 12; + xtime->tv_nsec = ((todval * 1000) >> 12); +} + +static inline unsigned long do_gettimeoffset(void) +{ + __u64 now; + + now = (get_clock() - jiffies_timer_cc) >> 12; + /* We require the offset from the latest update of xtime */ + now -= (__u64) wall_jiffies*USECS_PER_JIFFY; + return (unsigned long) now; +} + +/* + * This version of gettimeofday has microsecond resolution. + */ +void do_gettimeofday(struct timeval *tv) +{ + unsigned long flags; + unsigned long seq; + unsigned long usec, sec; + + do { + seq = read_seqbegin_irqsave(&xtime_lock, flags); + + sec = xtime.tv_sec; + usec = xtime.tv_nsec / 1000 + do_gettimeoffset(); + } while (read_seqretry_irqrestore(&xtime_lock, seq, flags)); + + while (usec >= 1000000) { + usec -= 1000000; + sec++; + } + + tv->tv_sec = sec; + tv->tv_usec = usec; +} + +EXPORT_SYMBOL(do_gettimeofday); + +int do_settimeofday(struct timespec *tv) +{ + time_t wtm_sec, sec = tv->tv_sec; + long wtm_nsec, nsec = tv->tv_nsec; + + if ((unsigned long)tv->tv_nsec >= NSEC_PER_SEC) + return -EINVAL; + + write_seqlock_irq(&xtime_lock); + /* This is revolting. We need to set the xtime.tv_nsec + * correctly. However, the value in this location is + * is value at the last tick. + * Discover what correction gettimeofday + * would have done, and then undo it! + */ + nsec -= do_gettimeoffset() * 1000; + + wtm_sec = wall_to_monotonic.tv_sec + (xtime.tv_sec - sec); + wtm_nsec = wall_to_monotonic.tv_nsec + (xtime.tv_nsec - nsec); + + set_normalized_timespec(&xtime, sec, nsec); + set_normalized_timespec(&wall_to_monotonic, wtm_sec, wtm_nsec); + + time_adjust = 0; /* stop active adjtime() */ + time_status |= STA_UNSYNC; + time_maxerror = NTP_PHASE_LIMIT; + time_esterror = NTP_PHASE_LIMIT; + write_sequnlock_irq(&xtime_lock); + clock_was_set(); + return 0; +} + +EXPORT_SYMBOL(do_settimeofday); + + +#ifdef CONFIG_PROFILING +#define s390_do_profile(regs) profile_tick(CPU_PROFILING, regs) +#else +#define s390_do_profile(regs) do { ; } while(0) +#endif /* CONFIG_PROFILING */ + + +/* + * timer_interrupt() needs to keep up the real-time clock, + * as well as call the "do_timer()" routine every clocktick + */ +void account_ticks(struct pt_regs *regs) +{ + __u64 tmp; + __u32 ticks, xticks; + + /* Calculate how many ticks have passed. */ + if (S390_lowcore.int_clock < S390_lowcore.jiffy_timer) { + /* + * We have to program the clock comparator even if + * no tick has passed. That happens if e.g. an i/o + * interrupt wakes up an idle processor that has + * switched off its hz timer. + */ + tmp = S390_lowcore.jiffy_timer + CPU_DEVIATION; + asm volatile ("SCKC %0" : : "m" (tmp)); + return; + } + tmp = S390_lowcore.int_clock - S390_lowcore.jiffy_timer; + if (tmp >= 2*CLK_TICKS_PER_JIFFY) { /* more than two ticks ? */ + ticks = __div(tmp, CLK_TICKS_PER_JIFFY) + 1; + S390_lowcore.jiffy_timer += + CLK_TICKS_PER_JIFFY * (__u64) ticks; + } else if (tmp >= CLK_TICKS_PER_JIFFY) { + ticks = 2; + S390_lowcore.jiffy_timer += 2*CLK_TICKS_PER_JIFFY; + } else { + ticks = 1; + S390_lowcore.jiffy_timer += CLK_TICKS_PER_JIFFY; + } + + /* set clock comparator for next tick */ + tmp = S390_lowcore.jiffy_timer + CPU_DEVIATION; + asm volatile ("SCKC %0" : : "m" (tmp)); + +#ifdef CONFIG_SMP + /* + * Do not rely on the boot cpu to do the calls to do_timer. + * Spread it over all cpus instead. + */ + write_seqlock(&xtime_lock); + if (S390_lowcore.jiffy_timer > xtime_cc) { + tmp = S390_lowcore.jiffy_timer - xtime_cc; + if (tmp >= 2*CLK_TICKS_PER_JIFFY) { + xticks = __div(tmp, CLK_TICKS_PER_JIFFY); + xtime_cc += (__u64) xticks * CLK_TICKS_PER_JIFFY; + } else { + xticks = 1; + xtime_cc += CLK_TICKS_PER_JIFFY; + } + while (xticks--) + do_timer(regs); + } + write_sequnlock(&xtime_lock); +#else + for (xticks = ticks; xticks > 0; xticks--) + do_timer(regs); +#endif + +#ifdef CONFIG_VIRT_CPU_ACCOUNTING + account_user_vtime(current); +#else + while (ticks--) + update_process_times(user_mode(regs)); +#endif + + s390_do_profile(regs); +} + +#ifdef CONFIG_NO_IDLE_HZ + +#ifdef CONFIG_NO_IDLE_HZ_INIT +int sysctl_hz_timer = 0; +#else +int sysctl_hz_timer = 1; +#endif + +/* + * Stop the HZ tick on the current CPU. + * Only cpu_idle may call this function. + */ +static inline void stop_hz_timer(void) +{ + __u64 timer; + + if (sysctl_hz_timer != 0) + return; + + cpu_set(smp_processor_id(), nohz_cpu_mask); + + /* + * Leave the clock comparator set up for the next timer + * tick if either rcu or a softirq is pending. + */ + if (rcu_pending(smp_processor_id()) || local_softirq_pending()) { + cpu_clear(smp_processor_id(), nohz_cpu_mask); + return; + } + + /* + * This cpu is going really idle. Set up the clock comparator + * for the next event. + */ + timer = (__u64) (next_timer_interrupt() - jiffies) + jiffies_64; + timer = jiffies_timer_cc + timer * CLK_TICKS_PER_JIFFY; + asm volatile ("SCKC %0" : : "m" (timer)); +} + +/* + * Start the HZ tick on the current CPU. + * Only cpu_idle may call this function. + */ +static inline void start_hz_timer(void) +{ + if (!cpu_isset(smp_processor_id(), nohz_cpu_mask)) + return; + account_ticks(__KSTK_PTREGS(current)); + cpu_clear(smp_processor_id(), nohz_cpu_mask); +} + +static int nohz_idle_notify(struct notifier_block *self, + unsigned long action, void *hcpu) +{ + switch (action) { + case CPU_IDLE: + stop_hz_timer(); + break; + case CPU_NOT_IDLE: + start_hz_timer(); + break; + } + return NOTIFY_OK; +} + +static struct notifier_block nohz_idle_nb = { + .notifier_call = nohz_idle_notify, +}; + +void __init nohz_init(void) +{ + if (register_idle_notifier(&nohz_idle_nb)) + panic("Couldn't register idle notifier"); +} + +#endif + +/* + * Start the clock comparator on the current CPU. + */ +void init_cpu_timer(void) +{ + unsigned long cr0; + __u64 timer; + + timer = jiffies_timer_cc + jiffies_64 * CLK_TICKS_PER_JIFFY; + S390_lowcore.jiffy_timer = timer + CLK_TICKS_PER_JIFFY; + timer += CLK_TICKS_PER_JIFFY + CPU_DEVIATION; + asm volatile ("SCKC %0" : : "m" (timer)); + /* allow clock comparator timer interrupt */ + __ctl_store(cr0, 0, 0); + cr0 |= 0x800; + __ctl_load(cr0, 0, 0); +} + +extern void vtime_init(void); + +/* + * Initialize the TOD clock and the CPU timer of + * the boot cpu. + */ +void __init time_init(void) +{ + __u64 set_time_cc; + int cc; + + /* kick the TOD clock */ + asm volatile ("STCK 0(%1)\n\t" + "IPM %0\n\t" + "SRL %0,28" : "=r" (cc) : "a" (&init_timer_cc) + : "memory", "cc"); + switch (cc) { + case 0: /* clock in set state: all is fine */ + break; + case 1: /* clock in non-set state: FIXME */ + printk("time_init: TOD clock in non-set state\n"); + break; + case 2: /* clock in error state: FIXME */ + printk("time_init: TOD clock in error state\n"); + break; + case 3: /* clock in stopped or not-operational state: FIXME */ + printk("time_init: TOD clock stopped/non-operational\n"); + break; + } + jiffies_timer_cc = init_timer_cc - jiffies_64 * CLK_TICKS_PER_JIFFY; + + /* set xtime */ + xtime_cc = init_timer_cc + CLK_TICKS_PER_JIFFY; + set_time_cc = init_timer_cc - 0x8126d60e46000000LL + + (0x3c26700LL*1000000*4096); + tod_to_timeval(set_time_cc, &xtime); + set_normalized_timespec(&wall_to_monotonic, + -xtime.tv_sec, -xtime.tv_nsec); + + /* request the clock comparator external interrupt */ + if (register_early_external_interrupt(0x1004, 0, + &ext_int_info_cc) != 0) + panic("Couldn't request external interrupt 0x1004"); + + init_cpu_timer(); + +#ifdef CONFIG_NO_IDLE_HZ + nohz_init(); +#endif + +#ifdef CONFIG_VIRT_TIMER + vtime_init(); +#endif +} + |