include/asm-sparc64/timer.h

   1 /* $Id: timer.h,v 1.2 1998/03/15 17:23:52 ecd Exp $
   2  * timer.h: System timer definitions for sun5.
   3  *
   4  * Copyright (C) 1997 David S. Miller (davem@caip.rutgers.edu)
   5  */
   6
   7 #ifndef _SPARC64_TIMER_H
   8 #define _SPARC64_TIMER_H
   9
  10 /* How timers work:
  11  *
  12  * On uniprocessors we just use counter zero for the system wide
  13  * ticker, this performs thread scheduling, clock book keeping,
  14  * and runs timer based events.  Previously we used the Ultra
  15  * %tick interrupt for this purpose.
  16  *
  17  * On multiprocessors we pick one cpu as the master level 10 tick
  18  * processor.  Here this counter zero tick handles clock book
  19  * keeping and timer events only.  Each Ultra has it's level
  20  * 14 %tick interrupt set to fire off as well, even the master
  21  * tick cpu runs this locally.  This ticker performs thread
  22  * scheduling, system/user tick counting for the current thread,
  23  * and also profiling if enabled.
  24  */
  25
  26 /* Two timers, traditionally steered to PIL's 10 and 14 respectively.
  27  * But since INO packets are used on sun5, we could use any PIL level
  28  * we like, however for now we use the normal ones.
  29  *
  30  * The 'reg' and 'interrupts' properties for these live in nodes named
  31  * 'counter-timer'.  The first of three 'reg' properties describe where
  32  * the sun5_timer registers are.  The other two I have no idea. (XXX)
  33  */
  34 struct sun5_timer {
  35         u64     count0;
  36         u64     limit0;
  37         u64     count1;
  38         u64     limit1;
  39 };
  40
  41 #define SUN5_LIMIT_ENABLE       0x80000000
  42 #define SUN5_LIMIT_TOZERO       0x40000000
  43 #define SUN5_LIMIT_ZRESTART     0x20000000
  44 #define SUN5_LIMIT_CMASK        0x1fffffff
  45
  46 /* Given a HZ value, set the limit register to so that the timer IRQ
  47  * gets delivered that often.
  48  */
  49 #define SUN5_HZ_TO_LIMIT(__hz)  (1000000/(__hz))
  50
  51 #ifdef __SMP__
  52 extern unsigned long timer_tick_offset;
  53 extern void timer_tick_interrupt(struct pt_regs *);
  54 #endif
  55
  56 #endif /* _SPARC64_TIMER_H */