arch/blackfin/include/asm/delay.h

   1 /*
   2  * U-boot - delay.h Routines for introducing delays
   3  *
   4  * Copyright (c) 2005-2007 Analog Devices Inc.
   5  *
   6  * SPDX-License-Identifier:     GPL-2.0+
   7  */
   8
   9 #ifndef _BLACKFIN_DELAY_H
  10 #define _BLACKFIN_DELAY_H
  11
  12 /*
  13  * Changes made by akbar.hussain@Lineo.com, for BLACKFIN
  14  * Copyright (C) 1994 Hamish Macdonald
  15  *
  16  * Delay routines, using a pre-computed "loops_per_second" value.
  17  */
  18
  19 extern __inline__ void __delay(unsigned long loops)
  20 {
  21         __asm__ __volatile__("1:\t%0 += -1;\n\t"
  22                              "cc = %0 == 0;\n\t"
  23                              "if ! cc jump 1b;\n":"=d"(loops)
  24                              :"0"(loops));
  25 }
  26
  27 /*
  28  * Use only for very small delays ( < 1 msec).  Should probably use a
  29  * lookup table, really, as the multiplications take much too long with
  30  * short delays.  This is a "reasonable" implementation, though (and the
  31  * first constant multiplications gets optimized away if the delay is
  32  * a constant)
  33  */
  34 extern __inline__ void __udelay(unsigned long usecs)
  35 {
  36         __delay(usecs);
  37 }
  38
  39 #endif