uml: GENERIC_CLOCKEVENTS support
[linux-2.6.git] / arch / um / kernel / time.c
index 7678bcf..0167848 100644 (file)
@@ -3,6 +3,7 @@
  * Licensed under the GPL
  */
 
+#include "linux/clockchips.h"
 #include "linux/interrupt.h"
 #include "linux/jiffies.h"
 #include "linux/threads.h"
@@ -24,9 +25,10 @@ static unsigned long long prev_nsecs[NR_CPUS];
 static long long delta[NR_CPUS];               /* Deviation per interval */
 #endif
 
-void timer_irq(struct uml_pt_regs *regs)
+void timer_handler(int sig, struct uml_pt_regs *regs)
 {
        unsigned long long ticks = 0;
+       unsigned long flags;
 #ifdef CONFIG_UML_REAL_TIME_CLOCK
        int c = cpu();
        if (prev_nsecs[c]) {
@@ -47,89 +49,82 @@ void timer_irq(struct uml_pt_regs *regs)
 #else
        ticks = 1;
 #endif
+
+       local_irq_save(flags);
        while (ticks > 0) {
                do_IRQ(TIMER_IRQ, regs);
                ticks--;
        }
+       local_irq_restore(flags);
 }
 
-/* Protects local_offset */
-static DEFINE_SPINLOCK(timer_spinlock);
-static unsigned long long local_offset = 0;
-
-static inline unsigned long long get_time(void)
+static void itimer_set_mode(enum clock_event_mode mode,
+                           struct clock_event_device *evt)
 {
-       unsigned long long nsecs;
-       unsigned long flags;
-
-       spin_lock_irqsave(&timer_spinlock, flags);
-       nsecs = os_nsecs();
-       nsecs += local_offset;
-       spin_unlock_irqrestore(&timer_spinlock, flags);
-
-       return nsecs;
+       switch(mode) {
+       case CLOCK_EVT_MODE_PERIODIC:
+               set_interval();
+               break;
+
+       case CLOCK_EVT_MODE_SHUTDOWN:
+       case CLOCK_EVT_MODE_UNUSED:
+               disable_timer();
+               break;
+       case CLOCK_EVT_MODE_ONESHOT:
+               BUG();
+               break;
+
+       case CLOCK_EVT_MODE_RESUME:
+               break;
+       }
 }
 
-irqreturn_t um_timer(int irq, void *dev)
+static struct clock_event_device itimer_clockevent = {
+       .name           = "itimer",
+       .rating         = 250,
+       .cpumask        = CPU_MASK_ALL,
+       .features       = CLOCK_EVT_FEAT_PERIODIC,
+       .set_mode       = itimer_set_mode,
+       .set_next_event = NULL,
+       .shift          = 32,
+       .irq            = 0,
+};
+
+static irqreturn_t um_timer(int irq, void *dev)
 {
-       unsigned long long nsecs;
-       unsigned long flags;
-
-       write_seqlock_irqsave(&xtime_lock, flags);
-
-       do_timer(1);
-
-#ifdef CONFIG_UML_REAL_TIME_CLOCK
-       nsecs = get_time();
-#else
-       nsecs = (unsigned long long) xtime.tv_sec * BILLION + xtime.tv_nsec +
-               BILLION / HZ;
-#endif
-       xtime.tv_sec = nsecs / NSEC_PER_SEC;
-       xtime.tv_nsec = nsecs - xtime.tv_sec * NSEC_PER_SEC;
-
-       write_sequnlock_irqrestore(&xtime_lock, flags);
+       (*itimer_clockevent.event_handler)(&itimer_clockevent);
 
        return IRQ_HANDLED;
 }
 
-static void register_timer(void)
+static void __init setup_itimer(void)
 {
        int err;
 
-       timer_init();
-
        err = request_irq(TIMER_IRQ, um_timer, IRQF_DISABLED, "timer", NULL);
        if (err != 0)
                printk(KERN_ERR "register_timer : request_irq failed - "
                       "errno = %d\n", -err);
 
-       err = set_interval();
-       if (err != 0)
-               printk(KERN_ERR "register_timer : set_interval failed - "
-                      "errno = %d\n", -err);
+       itimer_clockevent.mult = div_sc(HZ, NSEC_PER_SEC, 32);
+       itimer_clockevent.max_delta_ns =
+               clockevent_delta2ns(60 * HZ, &itimer_clockevent);
+       itimer_clockevent.min_delta_ns =
+               clockevent_delta2ns(1, &itimer_clockevent);
+       clockevents_register_device(&itimer_clockevent);
 }
 
 extern void (*late_time_init)(void);
 
-void time_init(void)
+void __init time_init(void)
 {
        long long nsecs;
 
+       timer_init();
+
        nsecs = os_nsecs();
        set_normalized_timespec(&wall_to_monotonic, -nsecs / BILLION,
                                -nsecs % BILLION);
        set_normalized_timespec(&xtime, nsecs / BILLION, nsecs % BILLION);
-       late_time_init = register_timer;
-}
-
-void timer_handler(int sig, struct uml_pt_regs *regs)
-{
-       if (current_thread->cpu == 0)
-               timer_irq(regs);
-       local_irq_disable();
-       irq_enter();
-       update_process_times(regs->is_user);
-       irq_exit();
-       local_irq_enable();
+       late_time_init = setup_itimer;
 }