include/asm-generic/delay.h

   1 #ifndef __ASM_GENERIC_DELAY_H
   2 #define __ASM_GENERIC_DELAY_H
   3
   4 /* Undefined functions to get compile-time errors */
   5 extern void __bad_udelay(void);
   6 extern void __bad_ndelay(void);
   7
   8 extern void __udelay(unsigned long usecs);
   9 extern void __ndelay(unsigned long nsecs);
  10 extern void __const_udelay(unsigned long xloops);
  11 extern void __delay(unsigned long loops);
  12
  13 /*
  14  * The weird n/20000 thing suppresses a "comparison is always false due to
  15  * limited range of data type" warning with non-const 8-bit arguments.
  16  */
  17
  18 /* 0x10c7 is 2**32 / 1000000 (rounded up) */
  19 #define udelay(n)                                                       \
  20         ({                                                              \
  21                 if (__builtin_constant_p(n)) {                          \
  22                         if ((n) / 20000 >= 1)                           \
  23                                  __bad_udelay();                        \
  24                         else                                            \
  25                                 __const_udelay((n) * 0x10c7ul);         \
  26                 } else {                                                \
  27                         __udelay(n);                                    \
  28                 }                                                       \
  29         })
  30
  31 /* 0x5 is 2**32 / 1000000000 (rounded up) */
  32 #define ndelay(n)                                                       \
  33         ({                                                              \
  34                 if (__builtin_constant_p(n)) {                          \
  35                         if ((n) / 20000 >= 1)                           \
  36                                 __bad_ndelay();                         \
  37                         else                                            \
  38                                 __const_udelay((n) * 5ul);              \
  39                 } else {                                                \
  40                         __ndelay(n);                                    \
  41                 }                                                       \
  42         })
  43
  44 #endif /* __ASM_GENERIC_DELAY_H */