include/asm-x86/tsc.h

   1 /*
   2  * x86 TSC related functions
   3  */
   4 #ifndef _ASM_X86_TSC_H
   5 #define _ASM_X86_TSC_H
   6
   7 #include <asm/processor.h>
   8
   9 #define NS_SCALE        10 /* 2^10, carefully chosen */
  10 #define US_SCALE        32 /* 2^32, arbitralrily chosen */
  11
  12 /*
  13  * Standard way to access the cycle counter.
  14  */
  15 typedef unsigned long long cycles_t;
  16
  17 extern unsigned int cpu_khz;
  18 extern unsigned int tsc_khz;
  19
  20 extern void disable_TSC(void);
  21 extern void enable_TSC(void);
  22
  23 static inline cycles_t get_cycles(void)
  24 {
  25         unsigned long long ret = 0;
  26
  27 #ifndef CONFIG_X86_TSC
  28         if (!cpu_has_tsc)
  29                 return 0;
  30 #endif
  31         rdtscll(ret);
  32
  33         return ret;
  34 }
  35
  36 static inline cycles_t vget_cycles(void)
  37 {
  38         /*
  39          * We only do VDSOs on TSC capable CPUs, so this shouldnt
  40          * access boot_cpu_data (which is not VDSO-safe):
  41          */
  42 #ifndef CONFIG_X86_TSC
  43         if (!cpu_has_tsc)
  44                 return 0;
  45 #endif
  46         return (cycles_t)__native_read_tsc();
  47 }
  48
  49 extern void tsc_init(void);
  50 extern void mark_tsc_unstable(char *reason);
  51 extern int unsynchronized_tsc(void);
  52 extern void init_tsc_clocksource(void);
  53 int check_tsc_unstable(void);
  54
  55 /*
  56  * Boot-time check whether the TSCs are synchronized across
  57  * all CPUs/cores:
  58  */
  59 extern void check_tsc_sync_source(int cpu);
  60 extern void check_tsc_sync_target(void);
  61
  62 extern void tsc_calibrate(void);
  63 extern int notsc_setup(char *);
  64
  65 #endif