1 files changed, 88 insertions, 43 deletions

diff --git a/arch/powerpc/kernel/time.c b/arch/powerpc/kernel/time.c
index e71a0d8c597a..d20947cf1735 100644
--- a/arch/powerpc/kernel/time.c
+++ b/arch/powerpc/kernel/time.c
@@ -73,6 +73,7 @@
 
 /* powerpc clocksource/clockevent code */
 
+#include <linux/clockchips.h>
 #include <linux/clocksource.h>
 
 static cycle_t rtc_read(void);
@@ -97,6 +98,27 @@ static struct clocksource clocksource_timebase = {
         .read         = timebase_read,
 };
 
+#define DECREMENTER_MAX 0x7fffffff
+
+static int decrementer_set_next_event(unsigned long evt,
+                                      struct clock_event_device *dev);
+static void decrementer_set_mode(enum clock_event_mode mode,
+                                 struct clock_event_device *dev);
+
+static struct clock_event_device decrementer_clockevent = {
+       .name           = "decrementer",
+       .rating         = 200,
+       .shift          = 32,
+       .mult           = 0,     /* To be filled in */
+       .irq            = 0,
+       .set_next_event = decrementer_set_next_event,
+       .set_mode       = decrementer_set_mode,
+       .features       = CLOCK_EVT_FEAT_ONESHOT,
+};
+
+static DEFINE_PER_CPU(struct clock_event_device, decrementers);
+void init_decrementer_clockevent(void);
+
 #ifdef CONFIG_PPC_ISERIES
 static unsigned long __initdata iSeries_recal_titan;
 static signed long __initdata iSeries_recal_tb;
@@ -517,10 +539,12 @@ void __init iSeries_time_init_early(void)
 void timer_interrupt(struct pt_regs * regs)
 {
         struct pt_regs *old_regs;
-        int next_dec;
         int cpu = smp_processor_id();
-        unsigned long ticks;
-        u64 tb_next_jiffy;
+        struct clock_event_device *evt = &per_cpu(decrementers, cpu);
+
+        /* Ensure a positive value is written to the decrementer, or else
+         * some CPUs will continuue to take decrementer exceptions */
+        set_dec(DECREMENTER_MAX);
 
 #ifdef CONFIG_PPC32
         if (atomic_read(&ppc_n_lost_interrupts) != 0)
@@ -530,7 +554,6 @@ void timer_interrupt(struct pt_regs * regs)
         old_regs = set_irq_regs(regs);
         irq_enter();
 
-        profile_tick(CPU_PROFILING);
         calculate_steal_time();
 
 #ifdef CONFIG_PPC_ISERIES
@@ -538,44 +561,20 @@ void timer_interrupt(struct pt_regs * regs)
                 get_lppaca()->int_dword.fields.decr_int = 0;
 #endif
 
-        while ((ticks = tb_ticks_since(per_cpu(last_jiffy, cpu)))
-               >= tb_ticks_per_jiffy) {
-                /* Update last_jiffy */
-                per_cpu(last_jiffy, cpu) += tb_ticks_per_jiffy;
-                /* Handle RTCL overflow on 601 */
-                if (__USE_RTC() && per_cpu(last_jiffy, cpu) >= 1000000000)
-                        per_cpu(last_jiffy, cpu) -= 1000000000;
-
-                /*
-                 * We cannot disable the decrementer, so in the period
-                 * between this cpu's being marked offline in cpu_online_map
-                 * and calling stop-self, it is taking timer interrupts.
-                 * Avoid calling into the scheduler rebalancing code if this
-                 * is the case.
-                 */
-                if (!cpu_is_offline(cpu))
-                        account_process_time(regs);
-
-                /*
-                 * No need to check whether cpu is offline here; boot_cpuid
-                 * should have been fixed up by now.
-                 */
-                if (cpu != boot_cpuid)
-                        continue;
+        /*
+         * We cannot disable the decrementer, so in the period
+         * between this cpu's being marked offline in cpu_online_map
+         * and calling stop-self, it is taking timer interrupts.
+         * Avoid calling into the scheduler rebalancing code if this
+         * is the case.
+         */
+        if (!cpu_is_offline(cpu))
+                account_process_time(regs);
 
-                write_seqlock(&xtime_lock);
-                tb_next_jiffy = tb_last_jiffy + tb_ticks_per_jiffy;
-                if (__USE_RTC() && tb_next_jiffy >= 1000000000)
-                        tb_next_jiffy -= 1000000000;
-                if (per_cpu(last_jiffy, cpu) >= tb_next_jiffy) {
-                        tb_last_jiffy = tb_next_jiffy;
-                        do_timer(1);
-                }
-                write_sequnlock(&xtime_lock);
-        }
-        
-        next_dec = tb_ticks_per_jiffy - ticks;
-        set_dec(next_dec);
+        if (evt->event_handler)
+                evt->event_handler(evt);
+        else
+                evt->set_next_event(DECREMENTER_MAX, evt);
 
 #ifdef CONFIG_PPC_ISERIES
         if (firmware_has_feature(FW_FEATURE_ISERIES) && hvlpevent_is_pending())
@@ -795,6 +794,53 @@ void __init clocksource_init(void)
                clock->name, clock->mult, clock->shift);
 }
 
+static int decrementer_set_next_event(unsigned long evt,
+                                      struct clock_event_device *dev)
+{
+        set_dec(evt);
+        return 0;
+}
+
+static void decrementer_set_mode(enum clock_event_mode mode,
+                                 struct clock_event_device *dev)
+{
+        if (mode != CLOCK_EVT_MODE_ONESHOT)
+                decrementer_set_next_event(DECREMENTER_MAX, dev);
+}
+
+static void register_decrementer_clockevent(int cpu)
+{
+        struct clock_event_device *dec = &per_cpu(decrementers, cpu);
+
+        *dec = decrementer_clockevent;
+        dec->cpumask = cpumask_of_cpu(cpu);
+
+        printk(KERN_ERR "clockevent: %s mult[%lx] shift[%d] cpu[%d]\n",
+               dec->name, dec->mult, dec->shift, cpu);
+
+        clockevents_register_device(dec);
+}
+
+void init_decrementer_clockevent(void)
+{
+        int cpu = smp_processor_id();
+
+        decrementer_clockevent.mult = div_sc(ppc_tb_freq, NSEC_PER_SEC,
+                                             decrementer_clockevent.shift);
+        decrementer_clockevent.max_delta_ns =
+                clockevent_delta2ns(DECREMENTER_MAX, &decrementer_clockevent);
+        decrementer_clockevent.min_delta_ns = 1000;
+
+        register_decrementer_clockevent(cpu);
+}
+
+void secondary_cpu_time_init(void)
+{
+        /* FIME: Should make unrelatred change to move snapshot_timebase
+         * call here ! */
+        register_decrementer_clockevent(smp_processor_id());
+}
+
 /* This function is only called on the boot processor */
 void __init time_init(void)
 {
@@ -908,8 +954,7 @@ void __init time_init(void)
         if (!firmware_has_feature(FW_FEATURE_ISERIES))
                 clocksource_init();
 
-        /* Not exact, but the timer interrupt takes care of this */
-        set_dec(tb_ticks_per_jiffy);
+        init_decrementer_clockevent();
 }