H. Peter Anvin | 1965aae | 2008-10-22 22:26:29 -0700 | [diff] [blame] | 1 | #ifndef _ASM_X86_TIMER_H |
| 2 | #define _ASM_X86_TIMER_H |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 3 | #include <linux/init.h> |
Shaohua Li | c3c433e | 2005-09-03 15:57:07 -0700 | [diff] [blame] | 4 | #include <linux/pm.h> |
Guillaume Chazarain | 53d517c | 2008-01-30 13:30:06 +0100 | [diff] [blame] | 5 | #include <linux/percpu.h> |
Ingo Molnar | 8e6dafd | 2009-02-23 00:34:39 +0100 | [diff] [blame] | 6 | #include <linux/interrupt.h> |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 7 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 8 | #define TICK_SIZE (tick_nsec / 1000) |
Zachary Amsden | 6cb9a83 | 2007-03-05 00:30:35 -0800 | [diff] [blame] | 9 | |
Zachary Amsden | 6cb9a83 | 2007-03-05 00:30:35 -0800 | [diff] [blame] | 10 | unsigned long long native_sched_clock(void); |
Alok Kataria | e93ef94 | 2008-07-01 11:43:36 -0700 | [diff] [blame] | 11 | unsigned long native_calibrate_tsc(void); |
Zachary Amsden | 6cb9a83 | 2007-03-05 00:30:35 -0800 | [diff] [blame] | 12 | |
Jaswinder Singh | cc03849 | 2008-07-21 21:52:51 +0530 | [diff] [blame] | 13 | #ifdef CONFIG_X86_32 |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 14 | extern int timer_ack; |
Ingo Molnar | 8e6dafd | 2009-02-23 00:34:39 +0100 | [diff] [blame] | 15 | extern irqreturn_t timer_interrupt(int irq, void *dev_id); |
Jaswinder Singh | cc03849 | 2008-07-21 21:52:51 +0530 | [diff] [blame] | 16 | #endif /* CONFIG_X86_32 */ |
Stephen Rothwell | 25c1a41 | 2009-03-30 11:10:27 +1100 | [diff] [blame] | 17 | extern int recalibrate_cpu_khz(void); |
Jaswinder Singh | cc03849 | 2008-07-21 21:52:51 +0530 | [diff] [blame] | 18 | |
| 19 | extern int no_timer_check; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 20 | |
Zachary Amsden | 6cb9a83 | 2007-03-05 00:30:35 -0800 | [diff] [blame] | 21 | #ifndef CONFIG_PARAVIRT |
Alok Kataria | e93ef94 | 2008-07-01 11:43:36 -0700 | [diff] [blame] | 22 | #define calibrate_tsc() native_calibrate_tsc() |
Zachary Amsden | 6cb9a83 | 2007-03-05 00:30:35 -0800 | [diff] [blame] | 23 | #endif |
| 24 | |
Guillaume Chazarain | 53d517c | 2008-01-30 13:30:06 +0100 | [diff] [blame] | 25 | /* Accelerators for sched_clock() |
Jeremy Fitzhardinge | 688340e | 2007-07-17 18:37:04 -0700 | [diff] [blame] | 26 | * convert from cycles(64bits) => nanoseconds (64bits) |
| 27 | * basic equation: |
| 28 | * ns = cycles / (freq / ns_per_sec) |
| 29 | * ns = cycles * (ns_per_sec / freq) |
| 30 | * ns = cycles * (10^9 / (cpu_khz * 10^3)) |
| 31 | * ns = cycles * (10^6 / cpu_khz) |
| 32 | * |
| 33 | * Then we use scaling math (suggested by george@mvista.com) to get: |
| 34 | * ns = cycles * (10^6 * SC / cpu_khz) / SC |
| 35 | * ns = cycles * cyc2ns_scale / SC |
| 36 | * |
| 37 | * And since SC is a constant power of two, we can convert the div |
| 38 | * into a shift. |
| 39 | * |
Guillaume Chazarain | 53d517c | 2008-01-30 13:30:06 +0100 | [diff] [blame] | 40 | * We can use khz divisor instead of mhz to keep a better precision, since |
Jeremy Fitzhardinge | 688340e | 2007-07-17 18:37:04 -0700 | [diff] [blame] | 41 | * cyc2ns_scale is limited to 10^6 * 2^10, which fits in 32 bits. |
| 42 | * (mathieu.desnoyers@polymtl.ca) |
| 43 | * |
| 44 | * -johnstul@us.ibm.com "math is hard, lets go shopping!" |
| 45 | */ |
Guillaume Chazarain | 53d517c | 2008-01-30 13:30:06 +0100 | [diff] [blame] | 46 | |
| 47 | DECLARE_PER_CPU(unsigned long, cyc2ns); |
Peter Zijlstra | 84599f8 | 2009-06-16 12:34:17 -0700 | [diff] [blame^] | 48 | DECLARE_PER_CPU(unsigned long long, cyc2ns_offset); |
Jeremy Fitzhardinge | 688340e | 2007-07-17 18:37:04 -0700 | [diff] [blame] | 49 | |
| 50 | #define CYC2NS_SCALE_FACTOR 10 /* 2^10, carefully chosen */ |
| 51 | |
Guillaume Chazarain | 53d517c | 2008-01-30 13:30:06 +0100 | [diff] [blame] | 52 | static inline unsigned long long __cycles_2_ns(unsigned long long cyc) |
Jeremy Fitzhardinge | 688340e | 2007-07-17 18:37:04 -0700 | [diff] [blame] | 53 | { |
Peter Zijlstra | 84599f8 | 2009-06-16 12:34:17 -0700 | [diff] [blame^] | 54 | int cpu = smp_processor_id(); |
| 55 | unsigned long long ns = per_cpu(cyc2ns_offset, cpu); |
| 56 | ns += cyc * per_cpu(cyc2ns, cpu) >> CYC2NS_SCALE_FACTOR; |
| 57 | return ns; |
Jeremy Fitzhardinge | 688340e | 2007-07-17 18:37:04 -0700 | [diff] [blame] | 58 | } |
| 59 | |
Guillaume Chazarain | 53d517c | 2008-01-30 13:30:06 +0100 | [diff] [blame] | 60 | static inline unsigned long long cycles_2_ns(unsigned long long cyc) |
| 61 | { |
| 62 | unsigned long long ns; |
| 63 | unsigned long flags; |
| 64 | |
| 65 | local_irq_save(flags); |
| 66 | ns = __cycles_2_ns(cyc); |
| 67 | local_irq_restore(flags); |
| 68 | |
| 69 | return ns; |
| 70 | } |
Jeremy Fitzhardinge | 688340e | 2007-07-17 18:37:04 -0700 | [diff] [blame] | 71 | |
H. Peter Anvin | 1965aae | 2008-10-22 22:26:29 -0700 | [diff] [blame] | 72 | #endif /* _ASM_X86_TIMER_H */ |