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/config.h>
  14 #include <linux/sched.h>
  15 #include <asm/param.h>
  16
  17 extern unsigned long loops_per_jiffy;
  18
  19 /*
  20  * Use only for very small delays (< 1 msec).
  21  *
  22  * The active part of our cycle counter is only 32-bits wide, and
  23  * we're treating the difference between two marks as signed.  On
  24  * a 1GHz box, that's about 2 seconds.
  25  */
  26
  27 void __delay(int loops)
  28 {
  29         long long dummy;
  30         __asm__ __volatile__("gettr     tr0, %1\n\t"
  31                              "pta       $+4, tr0\n\t"
  32                              "addi      %0, -1, %0\n\t"
  33                              "bne       %0, r63, tr0\n\t"
  34                              "ptabs     %1, tr0\n\t":"=r"(loops),
  35                              "=r"(dummy)
  36                              :"0"(loops));
  37 }
  38
  39 void __udelay(unsigned long long usecs, unsigned long lpj)
  40 {
  41         usecs *= (((unsigned long long) HZ << 32) / 1000000) * lpj;
  42         __delay((long long) usecs >> 32);
  43 }
  44
  45 void __ndelay(unsigned long long nsecs, unsigned long lpj)
  46 {
  47         nsecs *= (((unsigned long long) HZ << 32) / 1000000000) * lpj;
  48         __delay((long long) nsecs >> 32);
  49 }
  50
  51 void udelay(unsigned long usecs)
  52 {
  53         __udelay(usecs, loops_per_jiffy);
  54 }
  55
  56 void ndelay(unsigned long nsecs)
  57 {
  58         __ndelay(nsecs, loops_per_jiffy);
  59 }
  60