arch/sh64/lib/udelay.c

   1 /*
   2  * arch/sh64/lib/udelay.c
   3  *
   4  * Delay routines, using a pre-computed "loops_per_jiffy" value.
   5  *
   6  * Copyright (C) 2000, 2001  Paolo Alberelli
   7  * Copyright (C) 2003, 2004  Paul Mundt
   8  *
   9  * This file is subject to the terms and conditions of the GNU General Public
  10  * License.  See the file "COPYING" in the main directory of this archive
  11  * for more details.
  12  */
  13 #include <linux/sched.h>
  14 #include <asm/param.h>
  15
  16 extern unsigned long loops_per_jiffy;
  17
  18 /*
  19  * Use only for very small delays (< 1 msec).
  20  *
  21  * The active part of our cycle counter is only 32-bits wide, and
  22  * we're treating the difference between two marks as signed.  On
  23  * a 1GHz box, that's about 2 seconds.
  24  */
  25
  26 void __delay(int loops)
  27 {
  28         long long dummy;
  29         __asm__ __volatile__("gettr     tr0, %1\n\t"
  30                              "pta       $+4, tr0\n\t"
  31                              "addi      %0, -1, %0\n\t"
  32                              "bne       %0, r63, tr0\n\t"
  33                              "ptabs     %1, tr0\n\t":"=r"(loops),
  34                              "=r"(dummy)
  35                              :"0"(loops));
  36 }
  37
  38 void __udelay(unsigned long long usecs, unsigned long lpj)
  39 {
  40         usecs *= (((unsigned long long) HZ << 32) / 1000000) * lpj;
  41         __delay((long long) usecs >> 32);
  42 }
  43
  44 void __ndelay(unsigned long long nsecs, unsigned long lpj)
  45 {
  46         nsecs *= (((unsigned long long) HZ << 32) / 1000000000) * lpj;
  47         __delay((long long) nsecs >> 32);
  48 }
  49
  50 void udelay(unsigned long usecs)
  51 {
  52         __udelay(usecs, loops_per_jiffy);
  53 }
  54
  55 void ndelay(unsigned long nsecs)
  56 {
  57         __ndelay(nsecs, loops_per_jiffy);
  58 }
  59