xref: /openbmc/linux/arch/x86/include/asm/timer.h (revision b2441318)
1 /* SPDX-License-Identifier: GPL-2.0 */
2 #ifndef _ASM_X86_TIMER_H
3 #define _ASM_X86_TIMER_H
4 #include <linux/pm.h>
5 #include <linux/percpu.h>
6 #include <linux/interrupt.h>
7 #include <linux/math64.h>
8 
9 #define TICK_SIZE (tick_nsec / 1000)
10 
11 unsigned long long native_sched_clock(void);
12 extern void recalibrate_cpu_khz(void);
13 
14 extern int no_timer_check;
15 
16 extern bool using_native_sched_clock(void);
17 
18 /*
19  * We use the full linear equation: f(x) = a + b*x, in order to allow
20  * a continuous function in the face of dynamic freq changes.
21  *
22  * Continuity means that when our frequency changes our slope (b); we want to
23  * ensure that: f(t) == f'(t), which gives: a + b*t == a' + b'*t.
24  *
25  * Without an offset (a) the above would not be possible.
26  *
27  * See the comment near cycles_2_ns() for details on how we compute (b).
28  */
29 struct cyc2ns_data {
30 	u32 cyc2ns_mul;
31 	u32 cyc2ns_shift;
32 	u64 cyc2ns_offset;
33 }; /* 16 bytes */
34 
35 extern void cyc2ns_read_begin(struct cyc2ns_data *);
36 extern void cyc2ns_read_end(void);
37 
38 #endif /* _ASM_X86_TIMER_H */
39