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 000000000000..061e81138dc2
--- /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
+}
+