include/asm-blackfin/delay.h

   1 #ifndef _BLACKFIN_DELAY_H
   2 #define _BLACKFIN_DELAY_H
   3
   4 static inline void __delay(unsigned long loops)
   5 {
   6
   7 /* FIXME: Currently the assembler doesn't recognize Loop Register Clobbers,
   8    uncomment this as soon those are implemented */
   9 /*
  10       __asm__ __volatile__ (  "\t LSETUP (1f,1f) LC0= %0\n\t"
  11                               "1:\t NOP;\n\t"
  12                               : :"a" (loops)
  13                               : "LT0","LB0","LC0");
  14
  15 */
  16
  17         __asm__ __volatile__("[--SP] = LC0;\n\t"
  18                              "[--SP] = LT0;\n\t"
  19                              "[--SP] = LB0;\n\t"
  20                              "LSETUP (1f,1f) LC0 = %0;\n\t"
  21                              "1:\t NOP;\n\t"
  22                              "LB0 = [SP++];\n\t"
  23                                 "LT0 = [SP++];\n\t"
  24                                 "LC0 = [SP++];\n"
  25                                 :
  26                                 :"a" (loops));
  27 }
  28
  29 #include <linux/param.h>        /* needed for HZ */
  30
  31 /*
  32  * Use only for very small delays ( < 1 msec).  Should probably use a
  33  * lookup table, really, as the multiplications take much too long with
  34  * short delays.  This is a "reasonable" implementation, though (and the
  35  * first constant multiplications gets optimized away if the delay is
  36  * a constant)
  37  */
  38 static inline void udelay(unsigned long usecs)
  39 {
  40         extern unsigned long loops_per_jiffy;
  41         __delay(usecs * loops_per_jiffy / (1000000 / HZ));
  42 }
  43
  44 #endif                          /* defined(_BLACKFIN_DELAY_H) */