src/arch/i386/include/gpxe/bios_timer.h

   1 #ifndef _GPXE_BIOS_TIMER_H
   2 #define _GPXE_BIOS_TIMER_H
   3
   4 /** @file
   5  *
   6  * BIOS timer
   7  *
   8  */
   9
  10 FILE_LICENCE ( GPL2_OR_LATER );
  11
  12 #ifdef TIMER_PCBIOS
  13 #define TIMER_PREFIX_pcbios
  14 #else
  15 #define TIMER_PREFIX_pcbios __pcbios_
  16 #endif
  17
  18 #include <gpxe/timer2.h>
  19
  20 /**
  21  * Delay for a fixed number of microseconds
  22  *
  23  * @v usecs             Number of microseconds for which to delay
  24  */
  25 static inline __always_inline void
  26 TIMER_INLINE ( pcbios, udelay ) ( unsigned long usecs ) {
  27         /* BIOS timer is not high-resolution enough for udelay(), so
  28          * we use timer2
  29          */
  30         timer2_udelay ( usecs );
  31 }
  32
  33 /**
  34  * Get number of ticks per second
  35  *
  36  * @ret ticks_per_sec   Number of ticks per second
  37  */
  38 static inline __always_inline unsigned long
  39 TIMER_INLINE ( pcbios, ticks_per_sec ) ( void ) {
  40         /* BIOS timer ticks over at 18.2 ticks per second */
  41         return 18;
  42 }
  43
  44 #endif /* _GPXE_BIOS_TIMER_H */