include/asm-ia64/delay.h

   1 #ifndef _ASM_IA64_DELAY_H
   2 #define _ASM_IA64_DELAY_H
   3
   4 /*
   5  * Delay routines using a pre-computed "cycles/usec" value.
   6  *
   7  * Copyright (C) 1998, 1999 Hewlett-Packard Co
   8  * Copyright (C) 1998, 1999 David Mosberger-Tang <davidm@hpl.hp.com>
   9  * Copyright (C) 1999 VA Linux Systems
  10  * Copyright (C) 1999 Walt Drummond <drummond@valinux.com>
  11  * Copyright (C) 1999 Asit Mallick <asit.k.mallick@intel.com>
  12  * Copyright (C) 1999 Don Dugger <don.dugger@intel.com>
  13  */
  14
  15 #include <linux/config.h>
  16 #include <linux/kernel.h>
  17 #include <linux/sched.h>
  18 #include <linux/compiler.h>
  19
  20 #include <asm/processor.h>
  21
  22 static __inline__ void
  23 ia64_set_itm (unsigned long val)
  24 {
  25         __asm__ __volatile__("mov cr.itm=%0;; srlz.d;;" :: "r"(val) : "memory");
  26 }
  27
  28 static __inline__ unsigned long
  29 ia64_get_itm (void)
  30 {
  31         unsigned long result;
  32
  33         __asm__ __volatile__("mov %0=cr.itm;; srlz.d;;" : "=r"(result) :: "memory");
  34         return result;
  35 }
  36
  37 static __inline__ void
  38 ia64_set_itv (unsigned long val)
  39 {
  40         __asm__ __volatile__("mov cr.itv=%0;; srlz.d;;" :: "r"(val) : "memory");
  41 }
  42
  43 static __inline__ void
  44 ia64_set_itc (unsigned long val)
  45 {
  46         __asm__ __volatile__("mov ar.itc=%0;; srlz.d;;" :: "r"(val) : "memory");
  47 }
  48
  49 static __inline__ unsigned long
  50 ia64_get_itc (void)
  51 {
  52         unsigned long result;
  53
  54         __asm__ __volatile__("mov %0=ar.itc" : "=r"(result) :: "memory");
  55 #ifdef CONFIG_ITANIUM
  56         while (unlikely((__s32) result == -1))
  57                 __asm__ __volatile__("mov %0=ar.itc" : "=r"(result) :: "memory");
  58 #endif
  59         return result;
  60 }
  61
  62 static __inline__ void
  63 __delay (unsigned long loops)
  64 {
  65         unsigned long saved_ar_lc;
  66
  67         if (loops < 1)
  68                 return;
  69
  70         __asm__ __volatile__("mov %0=ar.lc;;" : "=r"(saved_ar_lc));
  71         __asm__ __volatile__("mov ar.lc=%0;;" :: "r"(loops - 1));
  72         __asm__ __volatile__("1:\tbr.cloop.sptk.few 1b;;");
  73         __asm__ __volatile__("mov ar.lc=%0" :: "r"(saved_ar_lc));
  74 }
  75
  76 static __inline__ void
  77 udelay (unsigned long usecs)
  78 {
  79         unsigned long start = ia64_get_itc();
  80         unsigned long cycles = usecs*local_cpu_data->cyc_per_usec;
  81
  82         while (ia64_get_itc() - start < cycles)
  83                 /* skip */;
  84 }
  85
  86 #endif /* _ASM_IA64_DELAY_H */