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