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 unsigned long long native_sched_clock(void); 10 extern void recalibrate_cpu_khz(void); 11 12 extern int no_timer_check; 13 14 extern bool using_native_sched_clock(void); 15 16 /* 17 * We use the full linear equation: f(x) = a + b*x, in order to allow 18 * a continuous function in the face of dynamic freq changes. 19 * 20 * Continuity means that when our frequency changes our slope (b); we want to 21 * ensure that: f(t) == f'(t), which gives: a + b*t == a' + b'*t. 22 * 23 * Without an offset (a) the above would not be possible. 24 * 25 * See the comment near cycles_2_ns() for details on how we compute (b). 26 */ 27 struct cyc2ns_data { 28 u32 cyc2ns_mul; 29 u32 cyc2ns_shift; 30 u64 cyc2ns_offset; 31 }; /* 16 bytes */ 32 33 extern void cyc2ns_read_begin(struct cyc2ns_data *); 34 extern void cyc2ns_read_end(void); 35 36 #endif /* _ASM_X86_TIMER_H */ 37