x86_64: Add (not yet used) clock event functions

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Chris Wright <chrisw@sous-sol.org>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Arjan van de Ven <arjan@linux.intel.com>

1 files changed, 79 insertions, 0 deletions

diff --git a/arch/x86/kernel/apic_64.c b/arch/x86/kernel/apic_64.c
index 40938ef99dc2..2c2807abe1d4 100644
--- a/arch/x86/kernel/apic_64.c
+++ b/arch/x86/kernel/apic_64.c
@@ -25,6 +25,7 @@
 #include <linux/sysdev.h>
 #include <linux/module.h>
 #include <linux/ioport.h>
+#include <linux/clockchips.h>
 
 #include <asm/atomic.h>
 #include <asm/smp.h>
@@ -57,6 +58,77 @@ static struct resource lapic_resource = {
 
 static unsigned int calibration_result;
 
+static int lapic_next_event(unsigned long delta,
+                            struct clock_event_device *evt);
+static void lapic_timer_setup(enum clock_event_mode mode,
+                              struct clock_event_device *evt);
+
+static void lapic_timer_broadcast(cpumask_t mask);
+
+static void __setup_APIC_LVTT(unsigned int clocks, int oneshot, int irqen);
+
+static struct clock_event_device lapic_clockevent = {
+        .name           = "lapic",
+        .features       = CLOCK_EVT_FEAT_PERIODIC | CLOCK_EVT_FEAT_ONESHOT
+                        | CLOCK_EVT_FEAT_C3STOP | CLOCK_EVT_FEAT_DUMMY,
+        .shift          = 32,
+        .set_mode       = lapic_timer_setup,
+        .set_next_event = lapic_next_event,
+        .broadcast      = lapic_timer_broadcast,
+        .rating         = 100,
+        .irq            = -1,
+};
+static DEFINE_PER_CPU(struct clock_event_device, lapic_events);
+
+static int lapic_next_event(unsigned long delta,
+                            struct clock_event_device *evt)
+{
+        apic_write(APIC_TMICT, delta);
+        return 0;
+}
+
+static void lapic_timer_setup(enum clock_event_mode mode,
+                              struct clock_event_device *evt)
+{
+        unsigned long flags;
+        unsigned int v;
+
+        /* Lapic used as dummy for broadcast ? */
+        if (evt->features & CLOCK_EVT_FEAT_DUMMY)
+                return;
+
+        local_irq_save(flags);
+
+        switch (mode) {
+        case CLOCK_EVT_MODE_PERIODIC:
+        case CLOCK_EVT_MODE_ONESHOT:
+                __setup_APIC_LVTT(calibration_result,
+                                  mode != CLOCK_EVT_MODE_PERIODIC, 1);
+                break;
+        case CLOCK_EVT_MODE_UNUSED:
+        case CLOCK_EVT_MODE_SHUTDOWN:
+                v = apic_read(APIC_LVTT);
+                v |= (APIC_LVT_MASKED | LOCAL_TIMER_VECTOR);
+                apic_write(APIC_LVTT, v);
+                break;
+        case CLOCK_EVT_MODE_RESUME:
+                /* Nothing to do here */
+                break;
+        }
+
+        local_irq_restore(flags);
+}
+
+/*
+ * Local APIC timer broadcast function
+ */
+static void lapic_timer_broadcast(cpumask_t mask)
+{
+#ifdef CONFIG_SMP
+        send_IPI_mask(mask, LOCAL_TIMER_VECTOR);
+#endif
+}
+
 /*
  * cpu_mask that denotes the CPUs that needs timer interrupt coming in as
  * IPIs in place of local APIC timers
@@ -866,6 +938,13 @@ static void __init calibrate_APIC_clock(void)
         printk(KERN_INFO "Detected %d.%03d MHz APIC timer.\n",
                 result / 1000 / 1000, result / 1000 % 1000);
 
+        /* Calculate the scaled math multiplication factor */
+        lapic_clockevent.mult = div_sc(result, NSEC_PER_SEC, 32);
+        lapic_clockevent.max_delta_ns =
+                clockevent_delta2ns(0x7FFFFF, &lapic_clockevent);
+        lapic_clockevent.min_delta_ns =
+                clockevent_delta2ns(0xF, &lapic_clockevent);
+
         calibration_result = result / HZ;
 }